Lysophosphatidic acid(LPA)is a pleiotropic lipid agonist essential for functions of the central nervous system(CNS).It is abundant in the developing and adult brain while its concentration in biological fluids,includi...Lysophosphatidic acid(LPA)is a pleiotropic lipid agonist essential for functions of the central nervous system(CNS).It is abundant in the developing and adult brain while its concentration in biological fluids,including cerebrospinal fluid,varies significantly(Figure 1Α;Yung et al.,2014).LPA actually corresponds to a variety of lipid species that include different stereoisomers with either saturated or unsaturated fatty acids bearing likely differentiated biological activities(Figure 1Α;Yung et al.,2014;Hernández-Araiza et al.,2018).展开更多
BACKGROUND Hepatocellular carcinoma(HCC)is a difficult cancer to manage due to its highly invasive and metastatic nature.AIM To investigate the molecular function of transmembrane channel-like 5(TMC5)in vitro and in v...BACKGROUND Hepatocellular carcinoma(HCC)is a difficult cancer to manage due to its highly invasive and metastatic nature.AIM To investigate the molecular function of transmembrane channel-like 5(TMC5)in vitro and in vivo,with the objective of identifying novel diagnosis and treatment targets for HCC.METHODS The expression of TMC in cancer and normal tissues,along with its correlation with HCC prognosis,was analyzed using the GENT2,GEPIA database,and Human Protein Atlas.COX analysis was conducted to assess the relationship between TMC5 expression and overall survival in TCGA-LIHC patients.Further experiments were conducted to investigate the effect of TMC5 in cancer progression through loss-and gain-of-function assays in vitro and in vivo.RESULTS Bioinformatics revealed that TMC5 expression was generally higher in tumors than in normal tissues,and its expression was associated with poorer patient survival outcomes.TMC5 expression in HCC tissues and cells was consistent with the results of the bioinformatics analysis.Suppression of TMC5 expression reduced migration,invasion,and proliferation,while also decreasing the expression of epithelial-mesenchymal transition(EMT)-associated molecules in MHCC97-LM3 cells.Conversely,higher TMC5 expression significantly increased cell migration,invasion,proliferation,and EMT in MHCC97 L cells.TMC5 knockdown significantly decreased both the formation and spread of nodules in liver tissue,whereas TMC5 overexpression promoted them.CONCLUSION Our study provides compelling evidence that TMC5 is highly expressed in HCC and drives cancer progression through the activation of EMT-mediated invasion.TMC5 could represent a valuable molecular target for the diagnosis and treatment of HCC.展开更多
BACKGROUND Although transmembrane protein 106C(TMEM106C)has been elucidated to be overexpressed in cancers,its underlying mechanisms have not yet been fully understood.AIM To investigate the expression levels and mole...BACKGROUND Although transmembrane protein 106C(TMEM106C)has been elucidated to be overexpressed in cancers,its underlying mechanisms have not yet been fully understood.AIM To investigate the expression levels and molecular mechanisms of TMEM106C across 34 different cancer types,including liver hepatocellular carcinoma(LIHC).METHODS We analyzed TMEM106C expression patterns in pan-cancers using microenvironment cell populations counter to evaluate its association with the tumor microenvironment.Gene set enrichment analysis was conducted to identify molecular pathways related to TMEM106C.Chromatin immunoprecipitation followed by sequencing(ChIP-seq)analysis was conducted to identify upstream transcriptional regulators of TMEM106C.In LIHC,we examined mRNA profiles,performed in-house quantitative polymerase chain reaction,immunohistochemistry,and constructed a co-expression gene network.Functional assays,including cell counting kit-8,cell cycle,apoptosis,migration,and invasion,were conducted.The effect of nitidine chloride(NC)on LIHC xenograft was evaluated through RNA sequencing and molecular docking.Finally,potential therapeutic agents targeting TMEM106C were predicted.RESULTS TMEM106C was significantly overexpressed in 27 different cancer types and presaged poor prognosis in four of these types,including LIHC.Across pan-cancers,TMEM106C was inversely correlated to the abundances of immune and stromal cells.Furthermore,TMEM106C was significantly linked to cell cycle and DNA replication pathways in pan-cancers.ChIP-seq analysis predicted CCCTC-binding factor as a pivotal transcriptional factor targeting the TMEM106C gene in pan-cancers.Integrated analysis showed that TMEM106C was upregulated in 4657 LIHC compared with 3652 normal liver tissue[combined standardized mean difference=1.31(1.09,1.52)].Inhouse LIHC samples verified the expression status of TMEM106C.Higher TMEM106C expression signified worse survival conditions in LIHC patients treated with sorafenib,a tyrosine kinase inhibitor(TKI).Co-expressed analysis revealed that TMEM106C were significantly enriched in the cell cycle pathway.Knockout experiments demonstrated that TMEM106C plays a crucial role in LIHC cell proliferation,migration,and invasion,with cell cycle arrest occurring at the DNA synthesis phase,and increased apoptosis.Notably,TMEM106C upregulation was attenuated by NC treatment.Finally,TMEM106C expression levels were significantly correlated with the drug sensitivity of anti-hepatocellular carcinoma agents,including JNJ-42756493,a TKI agent.CONCLUSION Overexpressed TMEM106C was predicted as an oncogene in pan-cancers,which may serve as a promising therapeutic target for various cancers,including LIHC.Targeting TMEM106C could potentially offer a novel direction in overcoming TKI resistance specifically in LIHC.Future research directions include in-depth experimental validation and exploration of TMEM106C’s role in other cancer types.展开更多
According to the second law of thermodynamics,spontaneous chemical processes will ultimately reach the equilibrium state with the lowest energy.However,in biological systems,there are numerous highenergy states far fr...According to the second law of thermodynamics,spontaneous chemical processes will ultimately reach the equilibrium state with the lowest energy.However,in biological systems,there are numerous highenergy states far from equilibrium.One typical example is the transmembrane ion-concentration gradient,which plays crucial roles in maintaining homeostasis,regulating cell volume,and enabling cell signaling.Transmembrane ion-concentration gradient is achieved by an active transport process that requires the input of energy and the action of pump proteins.Replicating this process with synthetic supramolecular systems is particularly challenging,requiring both the input of energy and very specific,spatiotemporal control over ion uptake and release.In nature,pump proteins,such as protein-based ion channels,have evolved highly intricate architectures to perform this function.In contrast,Aprahamian and coworkers recently developed a much simpler smallmolecule system that functions as a molecular ion pump,utilizing light energy to pump chloride ions across a hydrophobic barrier against the concentration gradient[1].展开更多
With the global advancement of the circular economy,integrating reverse osmosis(RO)or forward osmosis(FO)with anaerobic membrane bioreactor(AnMBR)offers a promising approach to simultaneously generate high-grade recla...With the global advancement of the circular economy,integrating reverse osmosis(RO)or forward osmosis(FO)with anaerobic membrane bioreactor(AnMBR)offers a promising approach to simultaneously generate high-grade reclaimed water,produce energy,and preserve valuable nutrients from municipal wastewater.However,the selectivity of these osmotic membranes towards ammonia nitrogen,a major component in municipal wastewater and anaerobic effluent,remains unsatisfactory due to its similar polarity and hydraulic radius to water molecules.Therefore,enhancing the ammonia nitrogen rejection of osmotic membranes is imperative to maximize the quality of reclaimed water and minimize the loss of ammonia nitrogen resources.Unfortunately,the current understanding of the mapping relationship between ammonia nitrogen transmembrane diffusion and the micro/nano-structure of osmotic membranes is not systematic,making precise optimization of the membranes challenging.Hence,this review comprehensively analyzed the diffusion behavior of ammonia nitrogen through osmotic membranes to lay the foundation for targeted regulation of membrane fine structure.Initially,the desire for ammonia/ammonium-rejecting membranes was highlighted by introducing current and promising osmotic membrane-based applications in municipal wastewater reclamation processes.Subsequently,the connection between the micro/nano-structure of osmotic membranes and the transmembrane diffusion behavior of ammonia nitrogen was explored by analyzing the effects of membrane characteristics on ammonia nitrogen transport using the DSPM-DE model.Finally,precise methods for modifying membranes to enhance ammonia nitrogen rejection were proposed.This review aims to offer theoretical insights guiding the development of RO and FO membranes with superior ammonia nitrogen rejection for efficient reclamation of municipal wastewater.展开更多
BACKGROUND Activation of the epithelial-mesenchymal transition(EMT),a pivotal process in tumor metastasis and evasion,as well as the NLRP3 inflammasome,both promote colorectal cancer(CRC)progression.Recent studies hav...BACKGROUND Activation of the epithelial-mesenchymal transition(EMT),a pivotal process in tumor metastasis and evasion,as well as the NLRP3 inflammasome,both promote colorectal cancer(CRC)progression.Recent studies have shown that Transmembrane protein 176B(TMEM176B)regulates NLRP3 and promotes CRC malignant phenotypes.AIM To investigate the role of TMEM176B in modulating NLRP3 inflammasome and its implications on EMT and tumor progression in CRC.METHODS CRC in situ mouse and co-cultured cell models were established using CT26 cells,BALB/c mice,and primary cultured mouse natural killer(NK)cells.Short hairpin RNA knocked down TMEM176B and NLRP3 expression in CT26 cells.Fluorescence imaging,Terminal deoxynucleotidyl transferase dUTP nick end labeling assays,immunohistochemistry staining,flow cytometry,and molecular assays were used to investigate the effects of TMEM176B knockdown on the NLRP3 inflammasome in NK cells to assess tumor metastasis,apoptosis,and EMT indicators.RESULTS Silencing TMEM176B in CRC mice significantly reduced tumor metastasis,proliferation,and EMT,while activating apoptosis,NLRP3 inflammasome,and NK cell activity.Furthermore,silencing TMEM176B in co-cultured cell models inhibited cell migration and invasion,and promoted apoptosis.The interference of NLRP3 reversed these effects by modulating key proteins such as phosphorylated nuclear factor kappa B subunit 1 p65,matrix metallopeptidase 9,and transforming growth factor-β.CONCLUSION This study highlights the critical role of TMEM176B/NLRP3 in CRC progression and provides a basis for targeting this axis as a novel therapeutic approach to manage CRC progression and metastasis.展开更多
Crimean-Congo hemorrhagic fever(CCHF)is a hemorrhagic fever caused by infection with the CCHF virus(CCHFV)and has a mortality rate of up to 30%.Thrombocytopenia is a hallmark of CCHF;however,the mechanisms underlying ...Crimean-Congo hemorrhagic fever(CCHF)is a hemorrhagic fever caused by infection with the CCHF virus(CCHFV)and has a mortality rate of up to 30%.Thrombocytopenia is a hallmark of CCHF;however,the mechanisms underlying this manifestation remain poorly understood.In addition to hemostasis,platelets play a crucial role in recognizing pathogens and mediating immune responses.We investigated the mechanisms underlying thrombocytopenia associated with CCHFV infection by analyzing the platelet transcriptome in mice.Interferon-induced transmembrane protein 3(IFITM3),a known antiviral factor,was significantly upregulated.The role of IFITM3 in response to CCHFV infection was characterized using the human megakaryoblast cell line MEG-01,considered a parental cell line of platelets.Although the CCHFV infection rate was limited,MEG-01 cells maintained the infection and replication of CCHFV,leading to increased IFITM3 protein expression.We demonstrated that IFITM3 overexpression efficiently inhibited CCHFV infection,whereas IFITM3 knockout promoted viral infection.An interaction between IFITM3 and the CCHFV glycoprotein Gc was identified,which suppressed CCHFV entry into cells.The IFITM3 CIL-TMD domain is critical for this interaction.These results suggest that IFITM3 is a restriction factor and plays an antiviral role during CCHFV infection.Elevated expression of IFITM3 in platelets indicates that this could be a common mechanism by which platelets protect against viruses,including CCHFV,which may reduce platelet consumption and destruction caused by CCHFV infection.These findings provide valuable insights into the pathogenesis of CCHF-associated thrombocytopenia and offer foundational theoretical support for future therapeutic strategies.展开更多
[Objective] The research aimed to construct the prokaryotic expression vector of VP5 protein of IBDV.The transmembrane region sequence of VP5 protein was knocked out.Moreover,the expression,separation and purification...[Objective] The research aimed to construct the prokaryotic expression vector of VP5 protein of IBDV.The transmembrane region sequence of VP5 protein was knocked out.Moreover,the expression,separation and purification of objective protein were carried out.[Method] PCR technology was used to respectively amplify the extracellular and intracellular fragments of VP5 gene of IBDV.Then,the two fragments were simultaneously linked to pET-28b（＋）,and it was the vector-intracellular fragment-extracellular fragment-vector.The recombinant expression plasmid pET-VP5-FC and the improved pET-VP5-SC of VP5 whose transmembrane region gene fragment was knocked out were constructed.Then,the expression plasmid was transformed into BL21（DE3）.After IPTG induction,the recombinant protein was purified by Ni affinity chromatography and the gel filtration chromatography.[Result] The soluble expressed VP5 of IBDV was obtained.[Conclusion] The research laid the foundation for further studying the structure and function of VP5 protein.展开更多
[Objective] To investigate the effect of quercetin on the proliferation and mitochondrial transmembrane potential of CBRH-7919 cells. [Method] The CBRH-7919 cells of hepatocarcinoma were cultured in vitro. After treat...[Objective] To investigate the effect of quercetin on the proliferation and mitochondrial transmembrane potential of CBRH-7919 cells. [Method] The CBRH-7919 cells of hepatocarcinoma were cultured in vitro. After treated with different concentrations of quercetin, the OD405 nm of CBRH-7919 cells was detected by using the acid phosphatase assy （APA）; morphologic changes of the cells were observed under inverted microscope; the mitochondrial transmembrane potential （△ψm） intensity changes of CBRH-7919 cells were analyzed by flow cytometry after stained with Rhodamine 123. [Result] Quercetin inhibited the proliferation of CBRH-7919 cells significantly, and the growth inhibitory effect presented time- and dose-dependent relationship. Typical decrease of cell density was observed by optical microscopy on the quercetin-treated cells. With the effect of 10 μg/ml quercetin on CBRH-7919 cells for 12, 24 and 48 h, the percentage of Rhodamine 123 stained hypofluorescence cells increased, while the mitochondrial transmembrane potential（△ψm） intensity of CBRH-7919 cells decreased. [Conclusion] Quercetin could inhibit the proliferation of CBRH-7919 cells in vitro, causing the decrease in mitochondrial transmembrane potential.展开更多
Tmnsmembrane（TM） protein plays an important role in the life activity of the cells, and the prediction of transmembrane helical segments （TMHs） is an important subject in the bioinformatics research. Thus far, sev...Tmnsmembrane（TM） protein plays an important role in the life activity of the cells, and the prediction of transmembrane helical segments （TMHs） is an important subject in the bioinformatics research. Thus far, several prediction methods have been reported, but there are some deficiencies in prediction accuracy and adaptability in these methods. In this paper, a method based on discrete wavelet transform （DWT） was developed to predict the TMHs. Two sets of test data sets containing total 60 protein sequences were utilized to access the effect of the method. Compared with the prediction results of TMHMM2.0 and MEMSAT, the obtained results indicate that the presented method has high prediction accuracy.展开更多
A new artificial transmembrane channel molecule bearing dihydrogen phosphate groups has been synthesized.The terminal dihydrogen phosphate groups enable the channel to be highly negatively charged at both ends of the ...A new artificial transmembrane channel molecule bearing dihydrogen phosphate groups has been synthesized.The terminal dihydrogen phosphate groups enable the channel to be highly negatively charged at both ends of the channel structures.The artificial channel could incorporate into the lipid bilayer efficiently under low concentration.The channel displays high NH4+/K+selectivity due to the electrostatic interaction and hydrogen bonding between NH4+and the terminal dihydrogen phosphate groups.展开更多
Interferon-inducible transmembrane protein 3(IFITM3)inhibits influenza virus infection by blocking viral membrane fusion,but the exact mechanism remains elusive.Here,we investigated the function and key region of IFIT...Interferon-inducible transmembrane protein 3(IFITM3)inhibits influenza virus infection by blocking viral membrane fusion,but the exact mechanism remains elusive.Here,we investigated the function and key region of IFITM3 in blocking influenza virus entry mediated by hemagglutinin(HA).The restriction of IFITM3 on HAmediated viral entry was confirmed by pseudovirus harboring HA protein from H5 and H7 influenza viruses.Subcellular co-localization and immunocoprecipitation analyses revealed that IFITM3 partially co-located with the full-length HA protein and could directly interact with HA_(2) subunit but not HA_(1) subunit of H5 and H7 virus.Truncated analyses showed that the transmembrane domain of the IFITM3 and HA_(2) subunit might play an important role in their interaction.Finally,this interaction of IFITM3 was also verified with HA_(2) subunits from other subtypes of influenza A virus and influenza B virus.Overall,our data demonstrate for the first time a direct interaction between IFITM3 and influenza HA protein via the transmembrane domain,providing a new perspective for further exploring the biological significance of IFITM3 restriction on influenza virus infection or HA-mediated antagonism or escape.展开更多
Objective To determine the region of human transmembrane tumor necrosis factor-alpha (TM-TNFa) , essential for cytotoxic activity a-gainst human breast cancer cell line MCF-7.Methods Single amino-acid-substituted TM-T...Objective To determine the region of human transmembrane tumor necrosis factor-alpha (TM-TNFa) , essential for cytotoxic activity a-gainst human breast cancer cell line MCF-7.Methods Single amino-acid-substituted TM-TNFa mutant proteins (muteins) were produced by in vitro transcription linked translation techniques. The cDNA of TM-TNFa was site-directed mutagenized by recombinant PCR.Results 13 single ammo-acid substituted TM-TNFa muteins were generated and assayed for cytotoxic activity. The cytotoxic activities of TM-TNFa muteins, eg, TM-TNFa -71/Lys, -28/Phe and 117/Leu were significantly decreased (P < 0.01) compared to that of parent TM-TNFa, 143/Tyr decreased 4-folds, and -17/Thr, -39/Ser, 119/His, 35/Gly, 95/Cys and 147/Phe decreased 1.5-2.5-folds, respectively. However, the cytotoxic activities of TM-TNFa-8/Arg, 31/Gly and 87/Phe showed no significant change. Conclusion These results indicate that the regions associated with cytotoxic-activity of TM-TNFa are different with that of secretory TNF-alpha (S-TNFa) . The inner cell region and transmembrane region of TM-TNFa are related to the cytotoxic activity of TM-TNFa.展开更多
Numerous membrane proteins are cleaved by tumor necrosis factor-α converting enzyme （TACE）, which causes the release of their ectodomains. An ADAM （a disintegrin and metalloprotease domain） family member, TACE co...Numerous membrane proteins are cleaved by tumor necrosis factor-α converting enzyme （TACE）, which causes the release of their ectodomains. An ADAM （a disintegrin and metalloprotease domain） family member, TACE contains several noncatalytic domains whose roles in ectodomain shedding have yet to be fully resolved. Here, we have explored the function of the transmembrane domain （TM） of TACE by coupling molecular engineering and functional analysis. A TM-free TACE construct that is anchored to the plasma membrane by a glycosylphosphatidylinositol （GPI）-binding polypeptide failed to restore shedding of transforming growth factor-or （TGF-α）, tumor necrosis factor-α （TNF-α） and L-selectin in cells lacking endogenous TACE activity. Substitution of the TACE TM with that of the prolactin receptor or platelet-derived growth factor receptor （PDGFR） also resulted in severe loss of TGF-α shedding, but had no effects on the cleavage of TNF-α and L-selectin. Replacement of the TM in TGF-α with that of L-selectin enabled TGF-α shedding by the TACE mutants carrying the TM of prolactin receptor and PDGFR. Taken together, our observations suggest that anchorage of TACE to the lipid bilayer through a TM is required for efficient cleavage of a broad spectrum of substrates, and that the amino-acid sequence of TACE TM may play a role in regulatory specificity among TACE substrates.展开更多
The salt-secreting mangrove, Avicennia marina, and non-salt-secreting mangrove, Kandelia candel were cultivated in sand with various salinities(0‰, 10‰, 20‰, 30‰, 40‰) for 60 d. Plasma membrane vesicles of high-p...The salt-secreting mangrove, Avicennia marina, and non-salt-secreting mangrove, Kandelia candel were cultivated in sand with various salinities(0‰, 10‰, 20‰, 30‰, 40‰) for 60 d. Plasma membrane vesicles of high-purity in leaves and roots of A.marina and K. candel seedlings were obtained by two-phase partitioning. The function of the plasma membranes, the activity of ATPase, membrane potential and transmembrane proton gradient, at various salinities were investigated. The results showed that within a certain range of salinity(A. marina and roots of K. candel: 0—30‰; leaves of K.candel: 0—20‰), the activity of ATPase increased with increasing salinity, while high salinity(above 30‰ or 20‰) inhibited ATPase activity. In comparison with A. marina, K. candel appeared to be more sensitive to salinity. The dynamics of membrane potential and transmembrane proton gradient in leaves and roots of A. marina and K. candel seedlings were similar to that of ATPase. When treated directly by NaCl all the indexes were inhibited markedly: there was a little increase within 0—10‰(K. candel) or 0—20‰(A. marina) followed by sharp declining. It indicated that the structure and function of plasma membrane was damaged severely.展开更多
AIM： To investigate the effect of tetramethylpyrazine （TMP）, an active compound from Ligustium Wollichii Franchat, on electrolyte transport across the distal colon of rodents and the mechanism involved.METHODS： Th...AIM： To investigate the effect of tetramethylpyrazine （TMP）, an active compound from Ligustium Wollichii Franchat, on electrolyte transport across the distal colon of rodents and the mechanism involved.METHODS： The short-circuit current （Isc） technique in conjunction with pharmacological agents and specific inhibitors were used in analyzing the electrolyte transport across the distal colon of rodents. The underlying cellular signaling mechanism was investigated by radioimmunoassay analysis （RIA） and a special mouse model of cystic fibrosis.RESULTS： IMP stimulated a conoentration-dependent rise in ISCl, which was dependent on both Cl^- and HCO3^-, and inhibited by apical application of diphenylamine-2,2＇-dicarboxylic acid （DPC） and glibenclamide, but resistant to 4,4＇-diisothiocyanatostilbene-2,2＇-disulfonic acid disodium salt hydrate （DIDS）. Removal of Na^＋ from basolateral solution almost completely abolished the Isc response to TMP, but it was insensitive to apical Na^＋ replacement or apical Na^＋ channel blocker, amiloride. Pretreatment of colonic mucosa with BAPTA-AM, a membrane-permeable selective Ca2＋ chelator, did not significantly alter the TMP-induced Iso No additive effect of forskolin and 3-isobutyl-l-methylxanthine （[BMX） was observed on the TMP-induced Isc, but it was significantly reduced by a protein kinase A inhibitor, H89.RIA results showed that TMP （1 mmol/L） elicited a significant increase in cellular cAMP production, which was similar to that elicited by the adenylate cyclase activator, forskolin （10μmol/L）. The TMP-elicited Isc as well as forskolin- or IBMX-induced Isc were abolished in mice with homozygous mutation of the cystic fibrosis transmembrane conductance regulator （CFTR） presenting defective CFTR functions and secretions.CONCLUSION： TMP may stimulate cAMP-dependent and CFTR-mediated Cl^- and HCO3^- secretion. This may have implications in the future development of alternative treatment for constipation.展开更多
Dysfunction of the cystic fibrosis transmembrane con-ductance regulator(CFTR) chloride channel causes cys-tic fibrosis, while inappropriate activity of this channeloccurs in secretory diarrhea and polycystic kidney di...Dysfunction of the cystic fibrosis transmembrane con-ductance regulator(CFTR) chloride channel causes cys-tic fibrosis, while inappropriate activity of this channeloccurs in secretory diarrhea and polycystic kidney dis-ease. Drugs that interact directly with CFTR are there-fore of interest in the treatment of a number of diseasestates. This review focuses on one class of small mol-ecules that interacts directly with CFTR, namely inhibi-tors that act by directly blocking chloride movementthrough the open channel pore. In theory such com-pounds could be of use in the treatment of diarrheaand polycystic kidney disease, however in practice allknown substances acting by this mechanism to inhibitCFTR function lack either the potency or specificity forin vivo use. Nevertheless, this theoretical pharmaco-logical usefulness set the scene for the developmentof more potent, specific CFTR inhibitors. Biophysically,open channel blockers have proven most useful as ex-perimental probes of the structure and function of theCFTR chloride channel pore. Most importantly, the useof these blockers has been fundamental in developing afunctional model of the pore that includes a wide innervestibule that uses positively charged amino acid sidechains to attract both permeant and blocking anionsfrom the cell cytoplasm. CFTR channels are also subjectto this kind of blocking action by endogenous anionspresent in the cell cytoplasm, and recently this blocking effect has been suggested to play a role in the physio-logical control of CFTR channel function, in particular as a novel mechanism linking CFTR function dynamically to the composition of epithelial cell secretions. It has also been suggested that future drugs could target this same pathway as a way of pharmacologically increasing CFTR activity in cystic fibrosis. Studying open channel blockers and their mechanisms of action has resulted in significant advances in our understanding of CFTR as a pharmacological target in disease states, of CFTR chan-nel structure and function, and of how CFTR activity is controlled by its local environment.展开更多
Cystic fibrosis transmembrane conductance regulator(CFTR), a glycoprotein with 1480 amino acids, has been well established as a chloride channel mainly expressed in the epithelial cells of various tissues and organs s...Cystic fibrosis transmembrane conductance regulator(CFTR), a glycoprotein with 1480 amino acids, has been well established as a chloride channel mainly expressed in the epithelial cells of various tissues and organs such as lungs, sweat glands, gastrointestinal system, and reproductive organs. Although defective CFTR leads to cystic fibrosis, a common genetic disorder in the Caucasian population, there is accumulating evidence that suggests a novel role of CFTR in various cancers, especially in gastroenterological cancers, such as pancreatic cancer and colon cancer. In this review, we summarize the emerging findings that link CFTR with various cancers, with focus on the association between CFTR defects and gastrointestinal cancers as well as the underlying mechanisms. Further study of CFTR in cancer biology may help pave a new way for the diagnosis and treatment of gastrointestinal cancers.展开更多
Membrane proteins are an important kind of proteins embedded in the membranes of cells and play crucial roles in living organisms, such as ion channels,transporters, receptors. Because it is difficult to determinate t...Membrane proteins are an important kind of proteins embedded in the membranes of cells and play crucial roles in living organisms, such as ion channels,transporters, receptors. Because it is difficult to determinate the membrane protein's structure by wet-lab experiments,accurate and fast amino acid sequence-based computational methods are highly desired. In this paper, we report an online prediction tool called Mem Brain, whose input is the amino acid sequence. Mem Brain consists of specialized modules for predicting transmembrane helices, residue–residue contacts and relative accessible surface area of a-helical membrane proteins. Mem Brain achieves aprediction accuracy of 97.9% of ATMH, 87.1% of AP,3.2 ± 3.0 of N-score, 3.1 ± 2.8 of C-score. Mem BrainContact obtains 62%/64.1% prediction accuracy on training and independent dataset on top L/5 contact prediction,respectively. And Mem Brain-Rasa achieves Pearson correlation coefficient of 0.733 and its mean absolute error of13.593. These prediction results provide valuable hints for revealing the structure and function of membrane proteins.Mem Brain web server is free for academic use and available at www.csbio.sjtu.edu.cn/bioinf/Mem Brain/.展开更多
Remifentanil is widely used to control intraoperative pain. However, its analgesic effect is limited by the generation of postoperative hyperalgesia. In this study, we investigated whether the impairment of transmembr...Remifentanil is widely used to control intraoperative pain. However, its analgesic effect is limited by the generation of postoperative hyperalgesia. In this study, we investigated whether the impairment of transmembrane protein 16C(TMEM16C)/Slack is required for a-amino-3-hydroxy-5-methyl-4-isoxazolepropionic receptor(AMPAR) activation in remifentanil-induced postoperative hyperalgesia. Remifentanil anesthesia reduced the paw withdrawal threshold from 2 h to 48 h postoperatively,with a decrease in the expression of TMEM16C and Slack in the dorsal root ganglia(DRG) and spinal cord.Knockdown of TMEM16C in the DRG reduced the expression of Slack and elevated the basal peripheral sensitivity and AMPAR expression and function. Overexpression of TMEM16C in the DRG impaired remifentanilinduced ERK1/2 phosphorylation and behavioral hyperalgesia. AMPAR-mediated current and neuronal excitability were downregulated by TMEM16C overexpression in the spinal cord. Taken together, these findings suggest that TMEM16C/Slack regulation of excitatory synaptic plasticity via GluA1-containing AMPARs is critical in the pathogenesis of remifentanil-induced postoperative hyperalgesia in rats.展开更多
基金supported by the Hellenic Foundation for Research and Innovation,HFRI,“2nd Call for HFRI Research Projects to support Faculty Members&Researchers”Project 02667 to GL.
文摘Lysophosphatidic acid(LPA)is a pleiotropic lipid agonist essential for functions of the central nervous system(CNS).It is abundant in the developing and adult brain while its concentration in biological fluids,including cerebrospinal fluid,varies significantly(Figure 1Α;Yung et al.,2014).LPA actually corresponds to a variety of lipid species that include different stereoisomers with either saturated or unsaturated fatty acids bearing likely differentiated biological activities(Figure 1Α;Yung et al.,2014;Hernández-Araiza et al.,2018).
基金Supported by the Yunnan Provincial Department of Science and Technology-Kunming Medical University Joint Special Project on Applied Basic Research,No.202401AY070001-132the Yunnan Provincial Science Foundation,No.2018FE001(-287)+1 种基金National Natural Science Foundation of China,No.81460443the Ten Thousand People Plan of Yunnan Province,No.KH-SWR-MY-2020-002.
文摘BACKGROUND Hepatocellular carcinoma(HCC)is a difficult cancer to manage due to its highly invasive and metastatic nature.AIM To investigate the molecular function of transmembrane channel-like 5(TMC5)in vitro and in vivo,with the objective of identifying novel diagnosis and treatment targets for HCC.METHODS The expression of TMC in cancer and normal tissues,along with its correlation with HCC prognosis,was analyzed using the GENT2,GEPIA database,and Human Protein Atlas.COX analysis was conducted to assess the relationship between TMC5 expression and overall survival in TCGA-LIHC patients.Further experiments were conducted to investigate the effect of TMC5 in cancer progression through loss-and gain-of-function assays in vitro and in vivo.RESULTS Bioinformatics revealed that TMC5 expression was generally higher in tumors than in normal tissues,and its expression was associated with poorer patient survival outcomes.TMC5 expression in HCC tissues and cells was consistent with the results of the bioinformatics analysis.Suppression of TMC5 expression reduced migration,invasion,and proliferation,while also decreasing the expression of epithelial-mesenchymal transition(EMT)-associated molecules in MHCC97-LM3 cells.Conversely,higher TMC5 expression significantly increased cell migration,invasion,proliferation,and EMT in MHCC97 L cells.TMC5 knockdown significantly decreased both the formation and spread of nodules in liver tissue,whereas TMC5 overexpression promoted them.CONCLUSION Our study provides compelling evidence that TMC5 is highly expressed in HCC and drives cancer progression through the activation of EMT-mediated invasion.TMC5 could represent a valuable molecular target for the diagnosis and treatment of HCC.
基金Supported by the National Natural Science Foundation of China,No.NSFC82160762,No.NSFC82460783Natural Science Foundation of Guangxi,No.2022GXNSFBA035657Innovation Project of Guangxi Graduate Education,No.JGY2023068,No.YCSW2023220.
文摘BACKGROUND Although transmembrane protein 106C(TMEM106C)has been elucidated to be overexpressed in cancers,its underlying mechanisms have not yet been fully understood.AIM To investigate the expression levels and molecular mechanisms of TMEM106C across 34 different cancer types,including liver hepatocellular carcinoma(LIHC).METHODS We analyzed TMEM106C expression patterns in pan-cancers using microenvironment cell populations counter to evaluate its association with the tumor microenvironment.Gene set enrichment analysis was conducted to identify molecular pathways related to TMEM106C.Chromatin immunoprecipitation followed by sequencing(ChIP-seq)analysis was conducted to identify upstream transcriptional regulators of TMEM106C.In LIHC,we examined mRNA profiles,performed in-house quantitative polymerase chain reaction,immunohistochemistry,and constructed a co-expression gene network.Functional assays,including cell counting kit-8,cell cycle,apoptosis,migration,and invasion,were conducted.The effect of nitidine chloride(NC)on LIHC xenograft was evaluated through RNA sequencing and molecular docking.Finally,potential therapeutic agents targeting TMEM106C were predicted.RESULTS TMEM106C was significantly overexpressed in 27 different cancer types and presaged poor prognosis in four of these types,including LIHC.Across pan-cancers,TMEM106C was inversely correlated to the abundances of immune and stromal cells.Furthermore,TMEM106C was significantly linked to cell cycle and DNA replication pathways in pan-cancers.ChIP-seq analysis predicted CCCTC-binding factor as a pivotal transcriptional factor targeting the TMEM106C gene in pan-cancers.Integrated analysis showed that TMEM106C was upregulated in 4657 LIHC compared with 3652 normal liver tissue[combined standardized mean difference=1.31(1.09,1.52)].Inhouse LIHC samples verified the expression status of TMEM106C.Higher TMEM106C expression signified worse survival conditions in LIHC patients treated with sorafenib,a tyrosine kinase inhibitor(TKI).Co-expressed analysis revealed that TMEM106C were significantly enriched in the cell cycle pathway.Knockout experiments demonstrated that TMEM106C plays a crucial role in LIHC cell proliferation,migration,and invasion,with cell cycle arrest occurring at the DNA synthesis phase,and increased apoptosis.Notably,TMEM106C upregulation was attenuated by NC treatment.Finally,TMEM106C expression levels were significantly correlated with the drug sensitivity of anti-hepatocellular carcinoma agents,including JNJ-42756493,a TKI agent.CONCLUSION Overexpressed TMEM106C was predicted as an oncogene in pan-cancers,which may serve as a promising therapeutic target for various cancers,including LIHC.Targeting TMEM106C could potentially offer a novel direction in overcoming TKI resistance specifically in LIHC.Future research directions include in-depth experimental validation and exploration of TMEM106C’s role in other cancer types.
基金financial supports of National Natural Science Foundation of China(22171226)Natural Science Basic Research Program of Shaanxi(2022JC-06).
文摘According to the second law of thermodynamics,spontaneous chemical processes will ultimately reach the equilibrium state with the lowest energy.However,in biological systems,there are numerous highenergy states far from equilibrium.One typical example is the transmembrane ion-concentration gradient,which plays crucial roles in maintaining homeostasis,regulating cell volume,and enabling cell signaling.Transmembrane ion-concentration gradient is achieved by an active transport process that requires the input of energy and the action of pump proteins.Replicating this process with synthetic supramolecular systems is particularly challenging,requiring both the input of energy and very specific,spatiotemporal control over ion uptake and release.In nature,pump proteins,such as protein-based ion channels,have evolved highly intricate architectures to perform this function.In contrast,Aprahamian and coworkers recently developed a much simpler smallmolecule system that functions as a molecular ion pump,utilizing light energy to pump chloride ions across a hydrophobic barrier against the concentration gradient[1].
基金supported by National Natural Science Foundation of China(No.52200051)Harbin Institute of Technology(No.HC202236)Outstanding Youth Fund of Heilongjiang Natural Science Foundation(No.YQ2023E021)。
文摘With the global advancement of the circular economy,integrating reverse osmosis(RO)or forward osmosis(FO)with anaerobic membrane bioreactor(AnMBR)offers a promising approach to simultaneously generate high-grade reclaimed water,produce energy,and preserve valuable nutrients from municipal wastewater.However,the selectivity of these osmotic membranes towards ammonia nitrogen,a major component in municipal wastewater and anaerobic effluent,remains unsatisfactory due to its similar polarity and hydraulic radius to water molecules.Therefore,enhancing the ammonia nitrogen rejection of osmotic membranes is imperative to maximize the quality of reclaimed water and minimize the loss of ammonia nitrogen resources.Unfortunately,the current understanding of the mapping relationship between ammonia nitrogen transmembrane diffusion and the micro/nano-structure of osmotic membranes is not systematic,making precise optimization of the membranes challenging.Hence,this review comprehensively analyzed the diffusion behavior of ammonia nitrogen through osmotic membranes to lay the foundation for targeted regulation of membrane fine structure.Initially,the desire for ammonia/ammonium-rejecting membranes was highlighted by introducing current and promising osmotic membrane-based applications in municipal wastewater reclamation processes.Subsequently,the connection between the micro/nano-structure of osmotic membranes and the transmembrane diffusion behavior of ammonia nitrogen was explored by analyzing the effects of membrane characteristics on ammonia nitrogen transport using the DSPM-DE model.Finally,precise methods for modifying membranes to enhance ammonia nitrogen rejection were proposed.This review aims to offer theoretical insights guiding the development of RO and FO membranes with superior ammonia nitrogen rejection for efficient reclamation of municipal wastewater.
基金Ministry of Education Industry-University Co-operation Collaborative Education Project,No.202102242020.
文摘BACKGROUND Activation of the epithelial-mesenchymal transition(EMT),a pivotal process in tumor metastasis and evasion,as well as the NLRP3 inflammasome,both promote colorectal cancer(CRC)progression.Recent studies have shown that Transmembrane protein 176B(TMEM176B)regulates NLRP3 and promotes CRC malignant phenotypes.AIM To investigate the role of TMEM176B in modulating NLRP3 inflammasome and its implications on EMT and tumor progression in CRC.METHODS CRC in situ mouse and co-cultured cell models were established using CT26 cells,BALB/c mice,and primary cultured mouse natural killer(NK)cells.Short hairpin RNA knocked down TMEM176B and NLRP3 expression in CT26 cells.Fluorescence imaging,Terminal deoxynucleotidyl transferase dUTP nick end labeling assays,immunohistochemistry staining,flow cytometry,and molecular assays were used to investigate the effects of TMEM176B knockdown on the NLRP3 inflammasome in NK cells to assess tumor metastasis,apoptosis,and EMT indicators.RESULTS Silencing TMEM176B in CRC mice significantly reduced tumor metastasis,proliferation,and EMT,while activating apoptosis,NLRP3 inflammasome,and NK cell activity.Furthermore,silencing TMEM176B in co-cultured cell models inhibited cell migration and invasion,and promoted apoptosis.The interference of NLRP3 reversed these effects by modulating key proteins such as phosphorylated nuclear factor kappa B subunit 1 p65,matrix metallopeptidase 9,and transforming growth factor-β.CONCLUSION This study highlights the critical role of TMEM176B/NLRP3 in CRC progression and provides a basis for targeting this axis as a novel therapeutic approach to manage CRC progression and metastasis.
基金supported by the the National Key R&D Program of China(2024YFC2310000)the Key Project of Key Laboratory of VirologyBiosafety in the Wuhan Institute of Virology,Chinese Academy of Sciences(2024JZZD-02),the Youth Project of the Wuhan Institute of Virology,Chinese Academy of Sciences(2023QNTJ-03)+2 种基金the"Open Competition for Selecting the Best Candidates"Project of the Wuhan East Lake New Technology Development Zone(2022KJB117)the Natural Science Foundation of Hubei Province(2024AFB986)the Medical Science Research Project of Wuhan Health Commission(WX23B09).
文摘Crimean-Congo hemorrhagic fever(CCHF)is a hemorrhagic fever caused by infection with the CCHF virus(CCHFV)and has a mortality rate of up to 30%.Thrombocytopenia is a hallmark of CCHF;however,the mechanisms underlying this manifestation remain poorly understood.In addition to hemostasis,platelets play a crucial role in recognizing pathogens and mediating immune responses.We investigated the mechanisms underlying thrombocytopenia associated with CCHFV infection by analyzing the platelet transcriptome in mice.Interferon-induced transmembrane protein 3(IFITM3),a known antiviral factor,was significantly upregulated.The role of IFITM3 in response to CCHFV infection was characterized using the human megakaryoblast cell line MEG-01,considered a parental cell line of platelets.Although the CCHFV infection rate was limited,MEG-01 cells maintained the infection and replication of CCHFV,leading to increased IFITM3 protein expression.We demonstrated that IFITM3 overexpression efficiently inhibited CCHFV infection,whereas IFITM3 knockout promoted viral infection.An interaction between IFITM3 and the CCHFV glycoprotein Gc was identified,which suppressed CCHFV entry into cells.The IFITM3 CIL-TMD domain is critical for this interaction.These results suggest that IFITM3 is a restriction factor and plays an antiviral role during CCHFV infection.Elevated expression of IFITM3 in platelets indicates that this could be a common mechanism by which platelets protect against viruses,including CCHFV,which may reduce platelet consumption and destruction caused by CCHFV infection.These findings provide valuable insights into the pathogenesis of CCHF-associated thrombocytopenia and offer foundational theoretical support for future therapeutic strategies.
基金Supported by the National Natural Science Fundation Item of China(30970578,31070651)"Excellent Talent Support Plan in NewCentury"of Ministry of Education(NECT-08-0731)~~
文摘[Objective] The research aimed to construct the prokaryotic expression vector of VP5 protein of IBDV.The transmembrane region sequence of VP5 protein was knocked out.Moreover,the expression,separation and purification of objective protein were carried out.[Method] PCR technology was used to respectively amplify the extracellular and intracellular fragments of VP5 gene of IBDV.Then,the two fragments were simultaneously linked to pET-28b（＋）,and it was the vector-intracellular fragment-extracellular fragment-vector.The recombinant expression plasmid pET-VP5-FC and the improved pET-VP5-SC of VP5 whose transmembrane region gene fragment was knocked out were constructed.Then,the expression plasmid was transformed into BL21（DE3）.After IPTG induction,the recombinant protein was purified by Ni affinity chromatography and the gel filtration chromatography.[Result] The soluble expressed VP5 of IBDV was obtained.[Conclusion] The research laid the foundation for further studying the structure and function of VP5 protein.
基金Supported by the Natural Science Foundation of Shandong Province(ZR2011CM021)the Science and Technology Plan of Binzhou Medical University(BY2010KJ087)~~
文摘[Objective] To investigate the effect of quercetin on the proliferation and mitochondrial transmembrane potential of CBRH-7919 cells. [Method] The CBRH-7919 cells of hepatocarcinoma were cultured in vitro. After treated with different concentrations of quercetin, the OD405 nm of CBRH-7919 cells was detected by using the acid phosphatase assy （APA）; morphologic changes of the cells were observed under inverted microscope; the mitochondrial transmembrane potential （△ψm） intensity changes of CBRH-7919 cells were analyzed by flow cytometry after stained with Rhodamine 123. [Result] Quercetin inhibited the proliferation of CBRH-7919 cells significantly, and the growth inhibitory effect presented time- and dose-dependent relationship. Typical decrease of cell density was observed by optical microscopy on the quercetin-treated cells. With the effect of 10 μg/ml quercetin on CBRH-7919 cells for 12, 24 and 48 h, the percentage of Rhodamine 123 stained hypofluorescence cells increased, while the mitochondrial transmembrane potential（△ψm） intensity of CBRH-7919 cells decreased. [Conclusion] Quercetin could inhibit the proliferation of CBRH-7919 cells in vitro, causing the decrease in mitochondrial transmembrane potential.
基金Project supported by National High-Technology Research andDevelopment Program of China (Grant No .2002AA234021)
文摘Tmnsmembrane（TM） protein plays an important role in the life activity of the cells, and the prediction of transmembrane helical segments （TMHs） is an important subject in the bioinformatics research. Thus far, several prediction methods have been reported, but there are some deficiencies in prediction accuracy and adaptability in these methods. In this paper, a method based on discrete wavelet transform （DWT） was developed to predict the TMHs. Two sets of test data sets containing total 60 protein sequences were utilized to access the effect of the method. Compared with the prediction results of TMHMM2.0 and MEMSAT, the obtained results indicate that the presented method has high prediction accuracy.
基金the National Natural Science Foundation of China (Nos.21725202,21572035)the National R&D Program of China (No.2017YFA0206901)STCSM (Nos.18XD1400800, 18JC1411600) for financial support
文摘A new artificial transmembrane channel molecule bearing dihydrogen phosphate groups has been synthesized.The terminal dihydrogen phosphate groups enable the channel to be highly negatively charged at both ends of the channel structures.The artificial channel could incorporate into the lipid bilayer efficiently under low concentration.The channel displays high NH4+/K+selectivity due to the electrostatic interaction and hydrogen bonding between NH4+and the terminal dihydrogen phosphate groups.
基金supported by the National Natural Science Foundation of China (31702210, 31972719)the CAMS Innovation Fund for Medical Sciences (2020–12M-5-001)
文摘Interferon-inducible transmembrane protein 3(IFITM3)inhibits influenza virus infection by blocking viral membrane fusion,but the exact mechanism remains elusive.Here,we investigated the function and key region of IFITM3 in blocking influenza virus entry mediated by hemagglutinin(HA).The restriction of IFITM3 on HAmediated viral entry was confirmed by pseudovirus harboring HA protein from H5 and H7 influenza viruses.Subcellular co-localization and immunocoprecipitation analyses revealed that IFITM3 partially co-located with the full-length HA protein and could directly interact with HA_(2) subunit but not HA_(1) subunit of H5 and H7 virus.Truncated analyses showed that the transmembrane domain of the IFITM3 and HA_(2) subunit might play an important role in their interaction.Finally,this interaction of IFITM3 was also verified with HA_(2) subunits from other subtypes of influenza A virus and influenza B virus.Overall,our data demonstrate for the first time a direct interaction between IFITM3 and influenza HA protein via the transmembrane domain,providing a new perspective for further exploring the biological significance of IFITM3 restriction on influenza virus infection or HA-mediated antagonism or escape.
文摘Objective To determine the region of human transmembrane tumor necrosis factor-alpha (TM-TNFa) , essential for cytotoxic activity a-gainst human breast cancer cell line MCF-7.Methods Single amino-acid-substituted TM-TNFa mutant proteins (muteins) were produced by in vitro transcription linked translation techniques. The cDNA of TM-TNFa was site-directed mutagenized by recombinant PCR.Results 13 single ammo-acid substituted TM-TNFa muteins were generated and assayed for cytotoxic activity. The cytotoxic activities of TM-TNFa muteins, eg, TM-TNFa -71/Lys, -28/Phe and 117/Leu were significantly decreased (P < 0.01) compared to that of parent TM-TNFa, 143/Tyr decreased 4-folds, and -17/Thr, -39/Ser, 119/His, 35/Gly, 95/Cys and 147/Phe decreased 1.5-2.5-folds, respectively. However, the cytotoxic activities of TM-TNFa-8/Arg, 31/Gly and 87/Phe showed no significant change. Conclusion These results indicate that the regions associated with cytotoxic-activity of TM-TNFa are different with that of secretory TNF-alpha (S-TNFa) . The inner cell region and transmembrane region of TM-TNFa are related to the cytotoxic activity of TM-TNFa.
文摘Numerous membrane proteins are cleaved by tumor necrosis factor-α converting enzyme （TACE）, which causes the release of their ectodomains. An ADAM （a disintegrin and metalloprotease domain） family member, TACE contains several noncatalytic domains whose roles in ectodomain shedding have yet to be fully resolved. Here, we have explored the function of the transmembrane domain （TM） of TACE by coupling molecular engineering and functional analysis. A TM-free TACE construct that is anchored to the plasma membrane by a glycosylphosphatidylinositol （GPI）-binding polypeptide failed to restore shedding of transforming growth factor-or （TGF-α）, tumor necrosis factor-α （TNF-α） and L-selectin in cells lacking endogenous TACE activity. Substitution of the TACE TM with that of the prolactin receptor or platelet-derived growth factor receptor （PDGFR） also resulted in severe loss of TGF-α shedding, but had no effects on the cleavage of TNF-α and L-selectin. Replacement of the TM in TGF-α with that of L-selectin enabled TGF-α shedding by the TACE mutants carrying the TM of prolactin receptor and PDGFR. Taken together, our observations suggest that anchorage of TACE to the lipid bilayer through a TM is required for efficient cleavage of a broad spectrum of substrates, and that the amino-acid sequence of TACE TM may play a role in regulatory specificity among TACE substrates.
文摘The salt-secreting mangrove, Avicennia marina, and non-salt-secreting mangrove, Kandelia candel were cultivated in sand with various salinities(0‰, 10‰, 20‰, 30‰, 40‰) for 60 d. Plasma membrane vesicles of high-purity in leaves and roots of A.marina and K. candel seedlings were obtained by two-phase partitioning. The function of the plasma membranes, the activity of ATPase, membrane potential and transmembrane proton gradient, at various salinities were investigated. The results showed that within a certain range of salinity(A. marina and roots of K. candel: 0—30‰; leaves of K.candel: 0—20‰), the activity of ATPase increased with increasing salinity, while high salinity(above 30‰ or 20‰) inhibited ATPase activity. In comparison with A. marina, K. candel appeared to be more sensitive to salinity. The dynamics of membrane potential and transmembrane proton gradient in leaves and roots of A. marina and K. candel seedlings were similar to that of ATPase. When treated directly by NaCl all the indexes were inhibited markedly: there was a little increase within 0—10‰(K. candel) or 0—20‰(A. marina) followed by sharp declining. It indicated that the structure and function of plasma membrane was damaged severely.
基金Supported by the Innovation and Technology Fund of Hong Kong, China
文摘AIM： To investigate the effect of tetramethylpyrazine （TMP）, an active compound from Ligustium Wollichii Franchat, on electrolyte transport across the distal colon of rodents and the mechanism involved.METHODS： The short-circuit current （Isc） technique in conjunction with pharmacological agents and specific inhibitors were used in analyzing the electrolyte transport across the distal colon of rodents. The underlying cellular signaling mechanism was investigated by radioimmunoassay analysis （RIA） and a special mouse model of cystic fibrosis.RESULTS： IMP stimulated a conoentration-dependent rise in ISCl, which was dependent on both Cl^- and HCO3^-, and inhibited by apical application of diphenylamine-2,2＇-dicarboxylic acid （DPC） and glibenclamide, but resistant to 4,4＇-diisothiocyanatostilbene-2,2＇-disulfonic acid disodium salt hydrate （DIDS）. Removal of Na^＋ from basolateral solution almost completely abolished the Isc response to TMP, but it was insensitive to apical Na^＋ replacement or apical Na^＋ channel blocker, amiloride. Pretreatment of colonic mucosa with BAPTA-AM, a membrane-permeable selective Ca2＋ chelator, did not significantly alter the TMP-induced Iso No additive effect of forskolin and 3-isobutyl-l-methylxanthine （[BMX） was observed on the TMP-induced Isc, but it was significantly reduced by a protein kinase A inhibitor, H89.RIA results showed that TMP （1 mmol/L） elicited a significant increase in cellular cAMP production, which was similar to that elicited by the adenylate cyclase activator, forskolin （10μmol/L）. The TMP-elicited Isc as well as forskolin- or IBMX-induced Isc were abolished in mice with homozygous mutation of the cystic fibrosis transmembrane conductance regulator （CFTR） presenting defective CFTR functions and secretions.CONCLUSION： TMP may stimulate cAMP-dependent and CFTR-mediated Cl^- and HCO3^- secretion. This may have implications in the future development of alternative treatment for constipation.
文摘Dysfunction of the cystic fibrosis transmembrane con-ductance regulator(CFTR) chloride channel causes cys-tic fibrosis, while inappropriate activity of this channeloccurs in secretory diarrhea and polycystic kidney dis-ease. Drugs that interact directly with CFTR are there-fore of interest in the treatment of a number of diseasestates. This review focuses on one class of small mol-ecules that interacts directly with CFTR, namely inhibi-tors that act by directly blocking chloride movementthrough the open channel pore. In theory such com-pounds could be of use in the treatment of diarrheaand polycystic kidney disease, however in practice allknown substances acting by this mechanism to inhibitCFTR function lack either the potency or specificity forin vivo use. Nevertheless, this theoretical pharmaco-logical usefulness set the scene for the developmentof more potent, specific CFTR inhibitors. Biophysically,open channel blockers have proven most useful as ex-perimental probes of the structure and function of theCFTR chloride channel pore. Most importantly, the useof these blockers has been fundamental in developing afunctional model of the pore that includes a wide innervestibule that uses positively charged amino acid sidechains to attract both permeant and blocking anionsfrom the cell cytoplasm. CFTR channels are also subjectto this kind of blocking action by endogenous anionspresent in the cell cytoplasm, and recently this blocking effect has been suggested to play a role in the physio-logical control of CFTR channel function, in particular as a novel mechanism linking CFTR function dynamically to the composition of epithelial cell secretions. It has also been suggested that future drugs could target this same pathway as a way of pharmacologically increasing CFTR activity in cystic fibrosis. Studying open channel blockers and their mechanisms of action has resulted in significant advances in our understanding of CFTR as a pharmacological target in disease states, of CFTR chan-nel structure and function, and of how CFTR activity is controlled by its local environment.
基金Supported by American Cancer Society Institutional Research to Li C,No.11-053-01-IRGNational Institutes of Health grant HL128647
文摘Cystic fibrosis transmembrane conductance regulator(CFTR), a glycoprotein with 1480 amino acids, has been well established as a chloride channel mainly expressed in the epithelial cells of various tissues and organs such as lungs, sweat glands, gastrointestinal system, and reproductive organs. Although defective CFTR leads to cystic fibrosis, a common genetic disorder in the Caucasian population, there is accumulating evidence that suggests a novel role of CFTR in various cancers, especially in gastroenterological cancers, such as pancreatic cancer and colon cancer. In this review, we summarize the emerging findings that link CFTR with various cancers, with focus on the association between CFTR defects and gastrointestinal cancers as well as the underlying mechanisms. Further study of CFTR in cancer biology may help pave a new way for the diagnosis and treatment of gastrointestinal cancers.
基金supported by the National Natural Science Foundation of China(Nos.61671288,91530321,61603161)Science and Technology Commission of Shanghai Municipality(Nos.16JC1404300,17JC1403500,16ZR1448700)
文摘Membrane proteins are an important kind of proteins embedded in the membranes of cells and play crucial roles in living organisms, such as ion channels,transporters, receptors. Because it is difficult to determinate the membrane protein's structure by wet-lab experiments,accurate and fast amino acid sequence-based computational methods are highly desired. In this paper, we report an online prediction tool called Mem Brain, whose input is the amino acid sequence. Mem Brain consists of specialized modules for predicting transmembrane helices, residue–residue contacts and relative accessible surface area of a-helical membrane proteins. Mem Brain achieves aprediction accuracy of 97.9% of ATMH, 87.1% of AP,3.2 ± 3.0 of N-score, 3.1 ± 2.8 of C-score. Mem BrainContact obtains 62%/64.1% prediction accuracy on training and independent dataset on top L/5 contact prediction,respectively. And Mem Brain-Rasa achieves Pearson correlation coefficient of 0.733 and its mean absolute error of13.593. These prediction results provide valuable hints for revealing the structure and function of membrane proteins.Mem Brain web server is free for academic use and available at www.csbio.sjtu.edu.cn/bioinf/Mem Brain/.
基金supported by the National Natural Science Foundation of China (82071243, 81801107, 81772043, and 81400908)Tianjin Natural Science Foundation (20JCYBJC00460)Young Elite Scientists Sponsorship Program by Tianjin Municipality, China (TJSQNTJ-2020-10)。
文摘Remifentanil is widely used to control intraoperative pain. However, its analgesic effect is limited by the generation of postoperative hyperalgesia. In this study, we investigated whether the impairment of transmembrane protein 16C(TMEM16C)/Slack is required for a-amino-3-hydroxy-5-methyl-4-isoxazolepropionic receptor(AMPAR) activation in remifentanil-induced postoperative hyperalgesia. Remifentanil anesthesia reduced the paw withdrawal threshold from 2 h to 48 h postoperatively,with a decrease in the expression of TMEM16C and Slack in the dorsal root ganglia(DRG) and spinal cord.Knockdown of TMEM16C in the DRG reduced the expression of Slack and elevated the basal peripheral sensitivity and AMPAR expression and function. Overexpression of TMEM16C in the DRG impaired remifentanilinduced ERK1/2 phosphorylation and behavioral hyperalgesia. AMPAR-mediated current and neuronal excitability were downregulated by TMEM16C overexpression in the spinal cord. Taken together, these findings suggest that TMEM16C/Slack regulation of excitatory synaptic plasticity via GluA1-containing AMPARs is critical in the pathogenesis of remifentanil-induced postoperative hyperalgesia in rats.
