AIM： To investigate the regulation of activin receptor-interacting protein 2 （ARIP2） expression and its possible relationships with collagen type Ⅳ （collagen Ⅳ） in mouse hepatoma cell line Hepal-6 cells. METHOD...AIM： To investigate the regulation of activin receptor-interacting protein 2 （ARIP2） expression and its possible relationships with collagen type Ⅳ （collagen Ⅳ） in mouse hepatoma cell line Hepal-6 cells. METHODS： The ARIP2 mRNA expression kinetics in Hepal-6 cells was detected by RT-PCR, and its regulation factors were analyzed by treatment with signal transduction activators such as phorbol 12-myristate 13-acetate （PMA）, forskolin and A23187. After pcDNA3- ARIP2 was transfected into Hepal-6 cells, the effects of ARIP2 overexpression on activin type Ⅱ receptor （ActRⅡ） and collagen Ⅳ expression were evaluated. RESULTS： The expression levels of ARIP2 mRNA in Hapel-6 cells were elevated in time-dependent manner 12 h after treatment with activin A and endotoxin LPS, but not changed evidently in the early stage of stimulation （2 or 4 h）. The ARIP2 mRNA expression was increased after stimulated with signal transduction activators such as PMA and forskolin in Hepal-6 cells, whereas decreased after treatment with A23187 （25.3% ± 5.7% vs 48.1% ± 3.6%, P 〈 0.01）. ARIP2 overexpression could remarkably suppress the expression of ActRⅡA mRNA in dose-dependent manner, but has no effect on ActRⅡB in Hepal-6 cells induced by activin A. Furthermore, we have found that overexpression of ARIP2 could inhibit collagen Ⅳ mRNA and protein expressions induced by activin A in Hapel-6 cells. CONCLUSION： These findings suggest that ARIP2 expression can be influenced by various factors. ARIP2 may participate in the negative feedback regulation of signal transduction in the late stage by affecting the expression of ActRIIA and play an important role in regulation of development of liver fibrosis induced by activin.展开更多
Overexpression of receptor-interacting protein 140（RIP140） promotes neuronal differentiation of N2 a cells via extracellular regulated kinase 1/2（ERK1/2） signaling.However,involvement of RIP140 in human neural dif...Overexpression of receptor-interacting protein 140（RIP140） promotes neuronal differentiation of N2 a cells via extracellular regulated kinase 1/2（ERK1/2） signaling.However,involvement of RIP140 in human neural differentiation remains unclear.We found both RIP140 and ERK1/2 expression increased during neural differentiation of H1 human embryonic stem cells.Moreover,RIP140 negatively correlated with stem cell markers Oct4 and Sox2 during early stages of neural differentiation,and positively correlated with the neural stem cell marker Nestin during later stages.Thus,ERK1/2 signaling may provide the molecular mechanism by which RIP140 takes part in neural differentiation to eventually affect the number of neurons produced.展开更多
Background：Abnormal neuronal differentiation plays an important role in central nervous system （CNS） development abnormalities such as Down syndrome （DS）,a disorder that results directly from overexpression of ge...Background：Abnormal neuronal differentiation plays an important role in central nervous system （CNS） development abnormalities such as Down syndrome （DS）,a disorder that results directly from overexpression of genes in trisomic cells.Receptor-interacting protein 140 （RIP 140） is significantly upregulated in DS brains,suggesting its involvement in DS CNS development abnormalities.However,the role of RIP140 in neuronal differentiation is still not clear.The current study aimed to investigate the effect of RIP 140 overexpression on the differentiation of neuro-2a （N2a） neuroblastoma cells,in vitro.Methods：Stably RIP 140-overexpressing N2a （N2a-RIP140） cells were used as a neurodevelopmental model,and were constructed by lipofection and overexpression validated by real-time polymerase chain reaction and Western blot.Retinoic acid （RA） was used to stimulate N2a differentiation.Combining the expression of Tuj 1 at the mRNA and protein levels,the percentage of cells baring neurites,and the number of neurites per cell body was semi-quantified to determine the effect of RIP 140 on differentiation of N2a cells.Furthermore,western blot and the ERK1/2 inhibitor U0126 were used to identify the specific signaling pathway by which RIP 140 induces differentiation of N2a cells.Statistical significance of the differences between groups was determined by one-way analysis of variance followed by the Dunnett test.Results：Compared to untransfected N2a cells RIP140 expression in N2a-RIP 140 cells was remarkably upregulated at both the mRNA and protein levels.N2a-RIP 140 cells had a significantly increased percentage of cells baring neurites,and numbers of neurites per cell,as compared to N2a cells,in the absence and presence of RA （P 〈 0.05）.In addition,Tuj l,a neuronal biomarker,was strongly upregulated in N2a-RIP140 cells （P 〈 0.05） and phosphorylated ERK1/2 （p-ERK1/2） levels in N2a-RIP140 cells were dramatically increased,while differentiation was inhibited by the ERK 1/2-specific inhibitor U0126.Conclusions：RIP140 overexpression promotes N2a cell neuronal differentiation by activating the ERK1/2 pathway.展开更多
This study aims to demonstrate that blocking the receptor-interacting protein2(Rip2)expression can decrease inflammatory cytokine production by macrophage and protect mice from endotoxin lethality.Murine Rip2 small in...This study aims to demonstrate that blocking the receptor-interacting protein2(Rip2)expression can decrease inflammatory cytokine production by macrophage and protect mice from endotoxin lethality.Murine Rip2 small interfering RNA(siRNA)plasmids were constructed and transfected into macrophage and Rip2 expression was detected with reverse transcription-polymerase chain reaction(RT-PCR)and western blot.Cell proliferation was assayed withMTT.TNF-a concentration was assayed with ELISA and high-mobility group box 1 protein(HMGB1)level with semi-quantitative western blot after lipopolysaccharide(LPS)stimulation.LPS challenge was given after the plasmids were injected into mice and the survival rate was calculated.Rip2 siRNA plasmid could block the mRNA and protein expression of Rip2 and promote cell proliferation.Blocking Rip2 could attenuate LPS-induced TNF-a and HMGB1 production.The HMGB1 expression in the liver decreased to(40.21±11.03)pg/g,and serum TNF-a level decreased to(300.43±59.26)ng/L(P<0.05).The survival rate of mice from endotoxemia was also improved(P<0.05).The results demonstrate that Rip2 siRNA plasmid can block the expression of Rip2,decrease the production of TNF-a and HMGB1 and protect mice from fatal endotoxemia.展开更多
The incidence and mortality rate of lung cancer rank among the highest worldwide,severely endangering human health and life.Metformin,an anti-diabetes drug,has been shown to elicit anticancer activities in various tum...The incidence and mortality rate of lung cancer rank among the highest worldwide,severely endangering human health and life.Metformin,an anti-diabetes drug,has been shown to elicit anticancer activities in various tumors.However,its underlying mechanisms remain elusive.In this work,we explore the role of receptor-interacting protein 1(RIP1)which plays a crucial role in the process of cell death,in metformin-induced anticancer activities in lung cancer.Metformin inhibits lung cancer cell proliferation in a dose-dependent manner and promotes apoptotic cell death,as evidenced by metformin-induced PARP and caspase cleavage.Furthermore,the pan-caspase inhibitor z-VAD-fmk reverses metformin-induced cell death.Western blot and qPCR results suggest that metformin markedly downregulates RIP1 expression without affecting its mRNA and ubiquitination levels(0 vs 80 mmol/L,100%vs 20%,100%vs 15%).Additionally,co-immunoprecipitation and immunofluorescence results reveal that metformin may suppress RIP1 expression in an Hsp70-dependent manner,as metformin promotes Hsp70 degradation,and Hsp70 endogenously interacts with RIP1.Subsequent CCK-8,flow cytometry,and Western blot analyses suggest that metformin decreases Hsp70/RIP1 expression through AMPK/PKA/GSK-3βaxis.Consistently,results from a subcutaneous transplant tumor model indicate that metformin retards tumor growth without affecting mouse body weight.Collectively,these data highlight the part of RIP1 in metformin-induced anticancer activities in lung cancer in vitro and in vivo,providing novel strategy for lung cancer administration.展开更多
OBJECTIVE To explore the effect of ligustroflavone on ischemic brain injury in stroke rat and the under⁃lying mechanisms.METHODS A rat model of ischemic stroke was established by middle cerebral artery occlusion(MCAO)...OBJECTIVE To explore the effect of ligustroflavone on ischemic brain injury in stroke rat and the under⁃lying mechanisms.METHODS A rat model of ischemic stroke was established by middle cerebral artery occlusion(MCAO).Administration of ligustroflavone(10,30,60 mg·kg-1,ig)15 min before ischemia,after which neurological deficit score and infarct volume were detected by longa score and TTC stain.The cell viability and necrosis rate of hypoxia-cultured PC12 cells(O2/N2/CO2,1:94:5,8 h)were evaluated by MTS and LDH release rate.Flow cytometry further verified the mortality rate of PC12 cells.Necroptosis-associated proteins(RIPK1,RIPK3 and MLKL/p-MLKL)were detected by Western blotting.The interaction between RIPK3 and RIPK1 or MLKL were confirmed by immunoprecipitation.Operating Environ⁃ment(MOE)program demonstrated the possible combination of ligustroflavone with RIPK1,RIPK3 and MLKL.RESULTS Ischemic injury(increase in neurological deficit score and infarct volume)and upregulation of necroptosis-associated proteins were showed in rat MCAO model.Administration of ligustroflavone(30 mg·kg^-1,ig)evidently improved neurological func⁃tion,reduced infarct volume,and decreased the levels of necroptosis-associated proteins except the RIPK1.Consistently,hypoxia-cultured PC12 cells caused cellular injury(LDH release and necroposis)concomitant with up-regulation of necroptosis-associated proteins,and these phenomena were blocked in the presence of ligustroflavone(25μmol·L^-1)except the elevated RIPK1 levels.Using the Molecular Operating Environment(MOE)program,we identified RIPK1,RIPK3,and MLKL as potential targets of ligustroflavone.Further studies showed that the interaction between RIPK3 and RIPK1 or MLKL was significantly enhanced,which was blocked in the presence of ligustroflavone.CONCLUSION Ligus⁃troflavone protects rat brain from ischemic injury,and its beneficial effect is related to the prevention of necroptosis through a mechanism involving targeting RIPK1,RIPK3,and/or MLKL.展开更多
Ischemic brain injury triggers neuronal cell death by apoptosis via caspase activation and by necroptosis through activation of the receptor-interacting protein kinases （RIPK） associated with the tumor necrosis fact...Ischemic brain injury triggers neuronal cell death by apoptosis via caspase activation and by necroptosis through activation of the receptor-interacting protein kinases （RIPK） associated with the tumor necrosis factor-alpha （TNF-a）/death receptor. Recent evidence shows RIPK inhibitors are neuroprotective and al- leviate ischemic brain injury in a number of animal models, however, most have not yet undergone clinical trials and safety in humans remains in question. Dabrafenib, originally identified as a B-raf inhibitor that is currently used to treat melanoma, was later revealed to be a potent RIPK3 inhibitor at micromolar con- centrations. Here, we investigated whether Dabrafenib would show a similar neuroprotective effect in mice subjected to ischemic brain injury by photothrombosis. Dabrafenib administered intraperitoneally at 10 mg/ kg one hour after photothrombosis-induced focal ischemic injury significantly reduced infarct lesion size in C57BL6 mice the following day, accompanied by a markedly attenuated upregulation of TNF-u. However, subsequent lower doses （5 mg/kg/day） failed to sustain this neuroprotective effect after 4 days. Dabrafenib bl ocked lipopolysaccharides-induced activation of TNF-ct in bone marrow-derived macrophages, suggesting that Dabrafenib may attenuate TNF-ct-induced necroptotic pathway after ischemic brain injury. Since Dab- rafenib is already in clinical use for the treatment of melanoma, it might be repurposed for stroke therapy.展开更多
PANoptosis is a newly identified type of regulated cell death that consists of pyroptosis,apoptosis,and nec roptosis,which simultaneously occur during the pathophysiological process of infectious and inflammatory dise...PANoptosis is a newly identified type of regulated cell death that consists of pyroptosis,apoptosis,and nec roptosis,which simultaneously occur during the pathophysiological process of infectious and inflammatory diseases.Although our previous lite rature mining study suggested that PANoptosis might occur in neuronal ischemia/repe rfusion injury,little experimental research has been reported on the existence of PANoptosis.In this study,we used in vivo and in vitro retinal neuronal models of ischemia/repe rfusion injury to investigate whether PAN optosis-like cell death(simultaneous occurrence of pyroptosis,apo ptosis,and necroptosis)exists in retinal neuronal ischemia/repe rfusion injury.Our results showed that ischemia/repe rfusion injury induced changes in morphological features and protein levels that indicate PANoptosis-like cell death in retinal neurons both in vitro and in vivo.Ischemia/repe rfusion inju ry also significantly upregulated caspase-1,caspase-8,and NLRP3 expression,which are important components of the PANoptosome.These results indicate the existence of PANoptosis-like cell death in ischemia/reperfusion injury of retinal neurons and provide preliminary experimental evidence for future study of this new type of regulated cell death.展开更多
Methamphetamine is one of the most prevalent drugs abused in the world.Methamphetamine abusers usually present with hyperpyrexia (39℃),hallucination and other psychiatric symptoms.However,the detailed mechanism under...Methamphetamine is one of the most prevalent drugs abused in the world.Methamphetamine abusers usually present with hyperpyrexia (39℃),hallucination and other psychiatric symptoms.However,the detailed mechanism underlying its neurotoxic action remains elusive.This study investigated the effects of methamphetamine + 39℃ on primary cortical neurons from the cortex of embryonic Sprague-Dawley rats.Primary cortex neurons were exposed to 1 mM methamphetamine + 39℃.Propidium iodide staining and lactate dehydrogenase release detection showed that methamphetamine + 39℃ triggered obvious necrosis-like death in cultured primary cortical neurons,which could be partially inhibited by receptor-interacting protein-1 (RIP1) inhibitor Necrostatin-1 partially.Western blot assay results showed that there were increases in the expressions of receptor-interacting protein-3 (RIP3) and mixed lineage kinase domain-like protein (MLKL) in the primary cortical neurons treated with 1 mM methamphetamine + 39℃ for 3 hours.After pre-treatment with RIP3 inhibitor GSK’872,propidium iodide staining and lactate dehydrogenase release detection showed that neuronal necrosis rate was significantly decreased;RIP3 and MLKL protein expression significantly decreased.Immunohistochemistry staining results also showed that the expressions of RIP3 and MLKL were up-regulated in brain specimens from humans who had died of methamphetamine abuse.Taken together,the above results suggest that methamphetamine + 39℃ can induce RIP3/MLKL regulated necroptosis,thereby resulting in neurotoxicity.The study protocol was approved by the Medical Ethics Committee of the Third Xiangya Hospital of Central South University,China (approval numbers: 2017-S026 and 2017-S033) on March 7,2017.展开更多
Oligodencrocytes（OLs） are the main glial cells of the central nervous system involved in myelination of axons. In multiple sclerosis（MS）, there is an imbalance between demyelination and remyelination processes, th...Oligodencrocytes（OLs） are the main glial cells of the central nervous system involved in myelination of axons. In multiple sclerosis（MS）, there is an imbalance between demyelination and remyelination processes, the last one performed by oligodendrocyte progenitor cells（OPCs） and OLs, resulting into a permanent demyelination, axonal damage and neuronal loss. In MS lesions, astrocytes and microglias play an important part in permeabilization of blood-brain barrier and initiation of OPCs proliferation. Migration and differentiation of OPCs are influenced by various factors and the process is finalized by insufficient acummulation of OLs into the MS lesion. In relation to all these processes, the author will discuss the potential targets for remyelination strategies.展开更多
Emerging studies of treating spinal cord injury （SCI） with adult stem cells led us to evaluate the effects of transplantation of hair follicle stem cells in rats with a compression-induced spinal cord lesion. Here, ...Emerging studies of treating spinal cord injury （SCI） with adult stem cells led us to evaluate the effects of transplantation of hair follicle stem cells in rats with a compression-induced spinal cord lesion. Here, we proposed a hypothesis that rat hair follicle stem cell transplantation can promote the recovery of injured spinal cord. Compression-induced spinal cord injury was induced in Wistar rats in this study. The bulge area of the rat vibdssa follicles was isolated, cultivated and characterized with nestin as a stem cell marker. 5-Bromo-2＇-deoxyuridine （BrdU） labeled bulge stem cells were transplanted into rats with spinal cord injury. Immunohistochemical staining results showed that some of the grafted cells could survive and differentiate into oligodendrocytes （receptor-interacting protein positive cells） and neuronal-like cells （~lll-tubulin positive cells） at 3 weeks after transplantation. In addition, recovery of hind limb locomotor function in spinal cord injury rats at 8 weeks following cell transplantation was assessed using the Basso, Beattie and Bresnahan （BBB） locomotor rating scale. The results demon- strate that the grafted hair follicle stem cells can survive for a long time period in vivo and differentiate into neuronal- and glial-like cells. These results suggest that hair follicle stem cells can promote the recovery of spinal cord injury.展开更多
Necroptosis is a tightly regulated form of necrosis that requires the activation of receptor-interacting protein(RIP)kinases RIPK1 and RIPK3,as well as the RIPK3 substrate mixed lineage kinase domain-like protein(MLKL...Necroptosis is a tightly regulated form of necrosis that requires the activation of receptor-interacting protein(RIP)kinases RIPK1 and RIPK3,as well as the RIPK3 substrate mixed lineage kinase domain-like protein(MLKL).Because of membrane rupture,necroptotic cells release damage-associated molecular patterns(DAMPs)that evoke immune responses.Necroptosis is emerging as an important cellular response in the modulation of cancer initiation,progression,and metastasis.Necroptosis of cancer cells is considered to be an immunogenic cell death capable of activating anti-tumor immunity.Necroptosis also participates in the promotion of myeloid cell-induced adaptive immune suppression and thus contributes to oncogenesis.In addition,necroptosis of endothelial cells and tumor cells is conducive to tumor metastasis.In this review,we summarize the current knowledge of the complex role of necroptosis in cancer and discuss the potential of targeting necroptosis components for cancer therapies.展开更多
Background:Receptor-interacting protein kinase 1(RIPK1),a serine/threonine protein kinase,is mainly activated by pro-inflammatory cytokines and pathogens,including severe acute respiratory syndrome coronavirus 2(SARS-...Background:Receptor-interacting protein kinase 1(RIPK1),a serine/threonine protein kinase,is mainly activated by pro-inflammatory cytokines and pathogens,including severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),and its activation could result in apoptosis,necroptosis,or inflammation.This study was conducted to evaluate the safety and efficacy of a potent and selective inhibitor of RIPK1,SIR1-365,in hospitalized patients with severe coronavirus disease 2019(COVID-19).Methods:This multicenter,randomized,double-blind,phase 1b study screened patients from December 18,2020 until November 27,2021.Adults hospitalized with severe COVID-19(diagnosed≤2 weeks before screening)were randomized 1:1 to receive oral placebo or SIR1-365100 mg three times daily for≤14 consecutive days,with standard-of-care.The primary objective was to evaluate SIR1-365 safety and tolerability.Secondary objectives included an assessment of SIR1-365 efficacy.Descriptive statistics were used to summarize safety.The study was not powered for efficacy testing.Relevant inferential statistical tests were used to aid interpretation of differences in clinical efficacy.Results:Forty-five patients were randomized,42 were treated.Eighteen patients experienced treatment-emergent adverse events(TEAEs)and 7 patients were≥grade 3.Fewer SIR1-365-treated vs.placebo-treated patients experienced TEAEs(30.4%vs.57.9%)and serious TEAEs(13.0%vs.26.3%)within 28 days of the first dose.There were no serious treatment-related TEAEs or deaths.Compare to placebo,SIR1-365 significantly increased arterial oxygenation from baseline to day 7(least-squares mean change[standard error]:109.4[26.4]vs.-24.2[23.6];P=0.0095),significantly reduced hospitalization duration after treatment(mean±standard deviation:[4.7±3.7]days vs.[8.6±5.6]days;P=0.0145)and respiratory failure incidence(8.3%vs.38.1%;two-sided P=0.0291)during the study,and numerically shortened the time to clinical improvement in World Health Organization ordinal scale(median:5.0 days vs.9.0 days,P=0.0766).Conclusions:SIR1-365 was well tolerated and demonstrated a trend toward quicker recovery than placebo in hospitalized patients with severe COVID-19.Trial Registration ClinicalTrials.gov number:NCT04622332.展开更多
Background:Osteoarthritis(OA)is a debilitating joint disorder characterized by pro-gressive cartilage degeneration.During OA,subchondral bone undergoes micro-structural and molecular changes that precede cartilage deg...Background:Osteoarthritis(OA)is a debilitating joint disorder characterized by pro-gressive cartilage degeneration.During OA,subchondral bone undergoes micro-structural and molecular changes that precede cartilage degradation.However,spe-cific mechanisms underlying metabolic dysregulation of the bone-cartilage unit remain unclear.This study aims to investigate the role of receptor-interacting protein kinase-3(RIP3)in OA progression,focusing on bone-cartilage metabolic homeostasis.Methods:RIP3-mediated pathological and metabolic alterations in chondrocytes,os-teoblasts,and bone marrow-derived macrophages(BMMs)were evaluated.RIP3-mediated OA manifestations in cartilage and,more importantly,subchondral bone were determined by intra-articular overexpression of RIP3 in rats.The protective effect of RIP3 deficiency on the bone-cartilage unit during OA was systematically investigated using Rip3 knockout mice.The CMap database was used to screen for compounds that abrogate RIP3-induced OA pathological changes.Results:RIP3 was upregulated in the cartilage and subchondral bone of OA patients and post-traumatic OA mouse model.RIP3 overexpression not only inhibited extra-cellular matrix(ECM)anabolism in chondrocytes but also attenuated osteoblast differentiation,whereas RIP3 deficiency blunted receptor activator of NF-kappaB ligand-mediated osteoclastogenesis of BMMs.Intra-articular RIP3 overexpression induced the imbalance of SP7+osteoblasts/tartrate-resistant acid phosphatase(TRAP)+osteoclasts within the subchondral bone in addition to cartilage degen-eration in rats,while Rip3 deletion significantly improved structural outcomes of the bone-cartilage unit,and achieved pain relief as well as functional improvement in surgery-induced and spontaneous OA mouse models.Mechanistically,RIP3 initiates OA by perturbing critical events,including cartilage metabolism,inflammatory re-sponses,senescence,and osteoclast differentiation.Clofibrate,a hypolipidemic drug,was identified as a novel RIP3 inhibitor that reverses ECM catabolism in OA.Conclusions:RIP3 is an essential governor of whole joint metabolic homeostasis by regulating both cartilage metabolism and subchondral bone remodeling.Reconstruction of the bone-cartilage unit by targeting RIP3 might provide a two-birds-one-stone approach for the development of future OA therapies.展开更多
基金Supported by the National Natural Science Foundation of China, No. 30170478 and 30571688Science Projects of Jilin Province of China, No. 20060928-01
文摘AIM： To investigate the regulation of activin receptor-interacting protein 2 （ARIP2） expression and its possible relationships with collagen type Ⅳ （collagen Ⅳ） in mouse hepatoma cell line Hepal-6 cells. METHODS： The ARIP2 mRNA expression kinetics in Hepal-6 cells was detected by RT-PCR, and its regulation factors were analyzed by treatment with signal transduction activators such as phorbol 12-myristate 13-acetate （PMA）, forskolin and A23187. After pcDNA3- ARIP2 was transfected into Hepal-6 cells, the effects of ARIP2 overexpression on activin type Ⅱ receptor （ActRⅡ） and collagen Ⅳ expression were evaluated. RESULTS： The expression levels of ARIP2 mRNA in Hapel-6 cells were elevated in time-dependent manner 12 h after treatment with activin A and endotoxin LPS, but not changed evidently in the early stage of stimulation （2 or 4 h）. The ARIP2 mRNA expression was increased after stimulated with signal transduction activators such as PMA and forskolin in Hepal-6 cells, whereas decreased after treatment with A23187 （25.3% ± 5.7% vs 48.1% ± 3.6%, P 〈 0.01）. ARIP2 overexpression could remarkably suppress the expression of ActRⅡA mRNA in dose-dependent manner, but has no effect on ActRⅡB in Hepal-6 cells induced by activin A. Furthermore, we have found that overexpression of ARIP2 could inhibit collagen Ⅳ mRNA and protein expressions induced by activin A in Hapel-6 cells. CONCLUSION： These findings suggest that ARIP2 expression can be influenced by various factors. ARIP2 may participate in the negative feedback regulation of signal transduction in the late stage by affecting the expression of ActRIIA and play an important role in regulation of development of liver fibrosis induced by activin.
基金supported by the National Natural Science Foundation of China,No.31340024
文摘Overexpression of receptor-interacting protein 140（RIP140） promotes neuronal differentiation of N2 a cells via extracellular regulated kinase 1/2（ERK1/2） signaling.However,involvement of RIP140 in human neural differentiation remains unclear.We found both RIP140 and ERK1/2 expression increased during neural differentiation of H1 human embryonic stem cells.Moreover,RIP140 negatively correlated with stem cell markers Oct4 and Sox2 during early stages of neural differentiation,and positively correlated with the neural stem cell marker Nestin during later stages.Thus,ERK1/2 signaling may provide the molecular mechanism by which RIP140 takes part in neural differentiation to eventually affect the number of neurons produced.
基金This research was supported by the grants from the National Natural Science Foundation of China （No. 30872792） and Chief Funds of the National Natural Science Foundation of China （No. 31340024）.
文摘Background：Abnormal neuronal differentiation plays an important role in central nervous system （CNS） development abnormalities such as Down syndrome （DS）,a disorder that results directly from overexpression of genes in trisomic cells.Receptor-interacting protein 140 （RIP 140） is significantly upregulated in DS brains,suggesting its involvement in DS CNS development abnormalities.However,the role of RIP140 in neuronal differentiation is still not clear.The current study aimed to investigate the effect of RIP 140 overexpression on the differentiation of neuro-2a （N2a） neuroblastoma cells,in vitro.Methods：Stably RIP 140-overexpressing N2a （N2a-RIP140） cells were used as a neurodevelopmental model,and were constructed by lipofection and overexpression validated by real-time polymerase chain reaction and Western blot.Retinoic acid （RA） was used to stimulate N2a differentiation.Combining the expression of Tuj 1 at the mRNA and protein levels,the percentage of cells baring neurites,and the number of neurites per cell body was semi-quantified to determine the effect of RIP 140 on differentiation of N2a cells.Furthermore,western blot and the ERK1/2 inhibitor U0126 were used to identify the specific signaling pathway by which RIP 140 induces differentiation of N2a cells.Statistical significance of the differences between groups was determined by one-way analysis of variance followed by the Dunnett test.Results：Compared to untransfected N2a cells RIP140 expression in N2a-RIP 140 cells was remarkably upregulated at both the mRNA and protein levels.N2a-RIP 140 cells had a significantly increased percentage of cells baring neurites,and numbers of neurites per cell,as compared to N2a cells,in the absence and presence of RA （P 〈 0.05）.In addition,Tuj l,a neuronal biomarker,was strongly upregulated in N2a-RIP140 cells （P 〈 0.05） and phosphorylated ERK1/2 （p-ERK1/2） levels in N2a-RIP140 cells were dramatically increased,while differentiation was inhibited by the ERK 1/2-specific inhibitor U0126.Conclusions：RIP140 overexpression promotes N2a cell neuronal differentiation by activating the ERK1/2 pathway.
文摘This study aims to demonstrate that blocking the receptor-interacting protein2(Rip2)expression can decrease inflammatory cytokine production by macrophage and protect mice from endotoxin lethality.Murine Rip2 small interfering RNA(siRNA)plasmids were constructed and transfected into macrophage and Rip2 expression was detected with reverse transcription-polymerase chain reaction(RT-PCR)and western blot.Cell proliferation was assayed withMTT.TNF-a concentration was assayed with ELISA and high-mobility group box 1 protein(HMGB1)level with semi-quantitative western blot after lipopolysaccharide(LPS)stimulation.LPS challenge was given after the plasmids were injected into mice and the survival rate was calculated.Rip2 siRNA plasmid could block the mRNA and protein expression of Rip2 and promote cell proliferation.Blocking Rip2 could attenuate LPS-induced TNF-a and HMGB1 production.The HMGB1 expression in the liver decreased to(40.21±11.03)pg/g,and serum TNF-a level decreased to(300.43±59.26)ng/L(P<0.05).The survival rate of mice from endotoxemia was also improved(P<0.05).The results demonstrate that Rip2 siRNA plasmid can block the expression of Rip2,decrease the production of TNF-a and HMGB1 and protect mice from fatal endotoxemia.
文摘The incidence and mortality rate of lung cancer rank among the highest worldwide,severely endangering human health and life.Metformin,an anti-diabetes drug,has been shown to elicit anticancer activities in various tumors.However,its underlying mechanisms remain elusive.In this work,we explore the role of receptor-interacting protein 1(RIP1)which plays a crucial role in the process of cell death,in metformin-induced anticancer activities in lung cancer.Metformin inhibits lung cancer cell proliferation in a dose-dependent manner and promotes apoptotic cell death,as evidenced by metformin-induced PARP and caspase cleavage.Furthermore,the pan-caspase inhibitor z-VAD-fmk reverses metformin-induced cell death.Western blot and qPCR results suggest that metformin markedly downregulates RIP1 expression without affecting its mRNA and ubiquitination levels(0 vs 80 mmol/L,100%vs 20%,100%vs 15%).Additionally,co-immunoprecipitation and immunofluorescence results reveal that metformin may suppress RIP1 expression in an Hsp70-dependent manner,as metformin promotes Hsp70 degradation,and Hsp70 endogenously interacts with RIP1.Subsequent CCK-8,flow cytometry,and Western blot analyses suggest that metformin decreases Hsp70/RIP1 expression through AMPK/PKA/GSK-3βaxis.Consistently,results from a subcutaneous transplant tumor model indicate that metformin retards tumor growth without affecting mouse body weight.Collectively,these data highlight the part of RIP1 in metformin-induced anticancer activities in lung cancer in vitro and in vivo,providing novel strategy for lung cancer administration.
基金National Natural Science Foundation of China(8157343081872873)Hunan Provincial Natural Science Foundation of China(2015JJ2156)
文摘OBJECTIVE To explore the effect of ligustroflavone on ischemic brain injury in stroke rat and the under⁃lying mechanisms.METHODS A rat model of ischemic stroke was established by middle cerebral artery occlusion(MCAO).Administration of ligustroflavone(10,30,60 mg·kg-1,ig)15 min before ischemia,after which neurological deficit score and infarct volume were detected by longa score and TTC stain.The cell viability and necrosis rate of hypoxia-cultured PC12 cells(O2/N2/CO2,1:94:5,8 h)were evaluated by MTS and LDH release rate.Flow cytometry further verified the mortality rate of PC12 cells.Necroptosis-associated proteins(RIPK1,RIPK3 and MLKL/p-MLKL)were detected by Western blotting.The interaction between RIPK3 and RIPK1 or MLKL were confirmed by immunoprecipitation.Operating Environ⁃ment(MOE)program demonstrated the possible combination of ligustroflavone with RIPK1,RIPK3 and MLKL.RESULTS Ischemic injury(increase in neurological deficit score and infarct volume)and upregulation of necroptosis-associated proteins were showed in rat MCAO model.Administration of ligustroflavone(30 mg·kg^-1,ig)evidently improved neurological func⁃tion,reduced infarct volume,and decreased the levels of necroptosis-associated proteins except the RIPK1.Consistently,hypoxia-cultured PC12 cells caused cellular injury(LDH release and necroposis)concomitant with up-regulation of necroptosis-associated proteins,and these phenomena were blocked in the presence of ligustroflavone(25μmol·L^-1)except the elevated RIPK1 levels.Using the Molecular Operating Environment(MOE)program,we identified RIPK1,RIPK3,and MLKL as potential targets of ligustroflavone.Further studies showed that the interaction between RIPK3 and RIPK1 or MLKL was significantly enhanced,which was blocked in the presence of ligustroflavone.CONCLUSION Ligus⁃troflavone protects rat brain from ischemic injury,and its beneficial effect is related to the prevention of necroptosis through a mechanism involving targeting RIPK1,RIPK3,and/or MLKL.
基金supported by grants from the Heart and Stroke Foundation of Canada(HHC,AFRS)the Canadian Institutes of Health Research(to HHC and AFRS)supported by a Mid-Career Investigator Award from the Heart and Stroke Foundation of Ontario
文摘Ischemic brain injury triggers neuronal cell death by apoptosis via caspase activation and by necroptosis through activation of the receptor-interacting protein kinases （RIPK） associated with the tumor necrosis factor-alpha （TNF-a）/death receptor. Recent evidence shows RIPK inhibitors are neuroprotective and al- leviate ischemic brain injury in a number of animal models, however, most have not yet undergone clinical trials and safety in humans remains in question. Dabrafenib, originally identified as a B-raf inhibitor that is currently used to treat melanoma, was later revealed to be a potent RIPK3 inhibitor at micromolar con- centrations. Here, we investigated whether Dabrafenib would show a similar neuroprotective effect in mice subjected to ischemic brain injury by photothrombosis. Dabrafenib administered intraperitoneally at 10 mg/ kg one hour after photothrombosis-induced focal ischemic injury significantly reduced infarct lesion size in C57BL6 mice the following day, accompanied by a markedly attenuated upregulation of TNF-u. However, subsequent lower doses （5 mg/kg/day） failed to sustain this neuroprotective effect after 4 days. Dabrafenib bl ocked lipopolysaccharides-induced activation of TNF-ct in bone marrow-derived macrophages, suggesting that Dabrafenib may attenuate TNF-ct-induced necroptotic pathway after ischemic brain injury. Since Dab- rafenib is already in clinical use for the treatment of melanoma, it might be repurposed for stroke therapy.
基金supported by the National Natural Science Foundation of China,Nos.81772134,81971891,82172196,81571939(ail to KX)the Key Laboratory of Emergency and Trauma(Hainan Medical University)of Ministry of Education,No.KLET-202108(to KX)+1 种基金the Fundamental Research Funds for the Central Universities of Central South University of China,No.2020zzts218(to WTY)Hunan Provincial Innovation Foundation for Postgraduate of China,No.CX20200116(to WTY)。
文摘PANoptosis is a newly identified type of regulated cell death that consists of pyroptosis,apoptosis,and nec roptosis,which simultaneously occur during the pathophysiological process of infectious and inflammatory diseases.Although our previous lite rature mining study suggested that PANoptosis might occur in neuronal ischemia/repe rfusion injury,little experimental research has been reported on the existence of PANoptosis.In this study,we used in vivo and in vitro retinal neuronal models of ischemia/repe rfusion injury to investigate whether PAN optosis-like cell death(simultaneous occurrence of pyroptosis,apo ptosis,and necroptosis)exists in retinal neuronal ischemia/repe rfusion injury.Our results showed that ischemia/repe rfusion injury induced changes in morphological features and protein levels that indicate PANoptosis-like cell death in retinal neurons both in vitro and in vivo.Ischemia/repe rfusion inju ry also significantly upregulated caspase-1,caspase-8,and NLRP3 expression,which are important components of the PANoptosome.These results indicate the existence of PANoptosis-like cell death in ischemia/reperfusion injury of retinal neurons and provide preliminary experimental evidence for future study of this new type of regulated cell death.
基金funded by the National Natural Science Foundation of China,No.81971891(to KX),81571939(to KX),81772134(to KX),81772024(to JY),and 81860781(to FXL)the Key Research and Development Program of Hunan Province of China,No.2018SK2091(to KX)+1 种基金the Natural Science Foundation of Hunan Province of China,No.2017JJ2339(to JY)the Wu Jie-Ping Medical Foundation of the Minister of Health of China,No.320.6750.14118(to KX)
文摘Methamphetamine is one of the most prevalent drugs abused in the world.Methamphetamine abusers usually present with hyperpyrexia (39℃),hallucination and other psychiatric symptoms.However,the detailed mechanism underlying its neurotoxic action remains elusive.This study investigated the effects of methamphetamine + 39℃ on primary cortical neurons from the cortex of embryonic Sprague-Dawley rats.Primary cortex neurons were exposed to 1 mM methamphetamine + 39℃.Propidium iodide staining and lactate dehydrogenase release detection showed that methamphetamine + 39℃ triggered obvious necrosis-like death in cultured primary cortical neurons,which could be partially inhibited by receptor-interacting protein-1 (RIP1) inhibitor Necrostatin-1 partially.Western blot assay results showed that there were increases in the expressions of receptor-interacting protein-3 (RIP3) and mixed lineage kinase domain-like protein (MLKL) in the primary cortical neurons treated with 1 mM methamphetamine + 39℃ for 3 hours.After pre-treatment with RIP3 inhibitor GSK’872,propidium iodide staining and lactate dehydrogenase release detection showed that neuronal necrosis rate was significantly decreased;RIP3 and MLKL protein expression significantly decreased.Immunohistochemistry staining results also showed that the expressions of RIP3 and MLKL were up-regulated in brain specimens from humans who had died of methamphetamine abuse.Taken together,the above results suggest that methamphetamine + 39℃ can induce RIP3/MLKL regulated necroptosis,thereby resulting in neurotoxicity.The study protocol was approved by the Medical Ethics Committee of the Third Xiangya Hospital of Central South University,China (approval numbers: 2017-S026 and 2017-S033) on March 7,2017.
文摘Oligodencrocytes（OLs） are the main glial cells of the central nervous system involved in myelination of axons. In multiple sclerosis（MS）, there is an imbalance between demyelination and remyelination processes, the last one performed by oligodendrocyte progenitor cells（OPCs） and OLs, resulting into a permanent demyelination, axonal damage and neuronal loss. In MS lesions, astrocytes and microglias play an important part in permeabilization of blood-brain barrier and initiation of OPCs proliferation. Migration and differentiation of OPCs are influenced by various factors and the process is finalized by insufficient acummulation of OLs into the MS lesion. In relation to all these processes, the author will discuss the potential targets for remyelination strategies.
基金financially supported by a grant from Iran University of Medical Sciences(Tehran–Iran),No.531
文摘Emerging studies of treating spinal cord injury （SCI） with adult stem cells led us to evaluate the effects of transplantation of hair follicle stem cells in rats with a compression-induced spinal cord lesion. Here, we proposed a hypothesis that rat hair follicle stem cell transplantation can promote the recovery of injured spinal cord. Compression-induced spinal cord injury was induced in Wistar rats in this study. The bulge area of the rat vibdssa follicles was isolated, cultivated and characterized with nestin as a stem cell marker. 5-Bromo-2＇-deoxyuridine （BrdU） labeled bulge stem cells were transplanted into rats with spinal cord injury. Immunohistochemical staining results showed that some of the grafted cells could survive and differentiate into oligodendrocytes （receptor-interacting protein positive cells） and neuronal-like cells （~lll-tubulin positive cells） at 3 weeks after transplantation. In addition, recovery of hind limb locomotor function in spinal cord injury rats at 8 weeks following cell transplantation was assessed using the Basso, Beattie and Bresnahan （BBB） locomotor rating scale. The results demon- strate that the grafted hair follicle stem cells can survive for a long time period in vivo and differentiate into neuronal- and glial-like cells. These results suggest that hair follicle stem cells can promote the recovery of spinal cord injury.
基金supported by the National Natural Science Foundation of China(Nos.31671436,31600133,31771533,and 31830051)the Priority Academic Program Development of Jiangsu Higher Education Institutions,the Natural Science Foundation of Jiangsu Province(No.BK20160314)+1 种基金the Fok Ying Tung Education Foundation for Young Teachers(No.151020)the Non-profit Central Research Institute Fund of Chinese Academy of Medical Sciences(Nos.2017NL31002 and 2017NL31004)
文摘Necroptosis is a tightly regulated form of necrosis that requires the activation of receptor-interacting protein(RIP)kinases RIPK1 and RIPK3,as well as the RIPK3 substrate mixed lineage kinase domain-like protein(MLKL).Because of membrane rupture,necroptotic cells release damage-associated molecular patterns(DAMPs)that evoke immune responses.Necroptosis is emerging as an important cellular response in the modulation of cancer initiation,progression,and metastasis.Necroptosis of cancer cells is considered to be an immunogenic cell death capable of activating anti-tumor immunity.Necroptosis also participates in the promotion of myeloid cell-induced adaptive immune suppression and thus contributes to oncogenesis.In addition,necroptosis of endothelial cells and tumor cells is conducive to tumor metastasis.In this review,we summarize the current knowledge of the complex role of necroptosis in cancer and discuss the potential of targeting necroptosis components for cancer therapies.
文摘Background:Receptor-interacting protein kinase 1(RIPK1),a serine/threonine protein kinase,is mainly activated by pro-inflammatory cytokines and pathogens,including severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),and its activation could result in apoptosis,necroptosis,or inflammation.This study was conducted to evaluate the safety and efficacy of a potent and selective inhibitor of RIPK1,SIR1-365,in hospitalized patients with severe coronavirus disease 2019(COVID-19).Methods:This multicenter,randomized,double-blind,phase 1b study screened patients from December 18,2020 until November 27,2021.Adults hospitalized with severe COVID-19(diagnosed≤2 weeks before screening)were randomized 1:1 to receive oral placebo or SIR1-365100 mg three times daily for≤14 consecutive days,with standard-of-care.The primary objective was to evaluate SIR1-365 safety and tolerability.Secondary objectives included an assessment of SIR1-365 efficacy.Descriptive statistics were used to summarize safety.The study was not powered for efficacy testing.Relevant inferential statistical tests were used to aid interpretation of differences in clinical efficacy.Results:Forty-five patients were randomized,42 were treated.Eighteen patients experienced treatment-emergent adverse events(TEAEs)and 7 patients were≥grade 3.Fewer SIR1-365-treated vs.placebo-treated patients experienced TEAEs(30.4%vs.57.9%)and serious TEAEs(13.0%vs.26.3%)within 28 days of the first dose.There were no serious treatment-related TEAEs or deaths.Compare to placebo,SIR1-365 significantly increased arterial oxygenation from baseline to day 7(least-squares mean change[standard error]:109.4[26.4]vs.-24.2[23.6];P=0.0095),significantly reduced hospitalization duration after treatment(mean±standard deviation:[4.7±3.7]days vs.[8.6±5.6]days;P=0.0145)and respiratory failure incidence(8.3%vs.38.1%;two-sided P=0.0291)during the study,and numerically shortened the time to clinical improvement in World Health Organization ordinal scale(median:5.0 days vs.9.0 days,P=0.0766).Conclusions:SIR1-365 was well tolerated and demonstrated a trend toward quicker recovery than placebo in hospitalized patients with severe COVID-19.Trial Registration ClinicalTrials.gov number:NCT04622332.
基金supported by the National Natural Science Foundation of China(32000923,82072486,and 81972101)Beijing Municipal Natural Science Foundation(7214304)Peking University Third Hospital Clinical Key Project Talent Program(BYSYZD2021039).
文摘Background:Osteoarthritis(OA)is a debilitating joint disorder characterized by pro-gressive cartilage degeneration.During OA,subchondral bone undergoes micro-structural and molecular changes that precede cartilage degradation.However,spe-cific mechanisms underlying metabolic dysregulation of the bone-cartilage unit remain unclear.This study aims to investigate the role of receptor-interacting protein kinase-3(RIP3)in OA progression,focusing on bone-cartilage metabolic homeostasis.Methods:RIP3-mediated pathological and metabolic alterations in chondrocytes,os-teoblasts,and bone marrow-derived macrophages(BMMs)were evaluated.RIP3-mediated OA manifestations in cartilage and,more importantly,subchondral bone were determined by intra-articular overexpression of RIP3 in rats.The protective effect of RIP3 deficiency on the bone-cartilage unit during OA was systematically investigated using Rip3 knockout mice.The CMap database was used to screen for compounds that abrogate RIP3-induced OA pathological changes.Results:RIP3 was upregulated in the cartilage and subchondral bone of OA patients and post-traumatic OA mouse model.RIP3 overexpression not only inhibited extra-cellular matrix(ECM)anabolism in chondrocytes but also attenuated osteoblast differentiation,whereas RIP3 deficiency blunted receptor activator of NF-kappaB ligand-mediated osteoclastogenesis of BMMs.Intra-articular RIP3 overexpression induced the imbalance of SP7+osteoblasts/tartrate-resistant acid phosphatase(TRAP)+osteoclasts within the subchondral bone in addition to cartilage degen-eration in rats,while Rip3 deletion significantly improved structural outcomes of the bone-cartilage unit,and achieved pain relief as well as functional improvement in surgery-induced and spontaneous OA mouse models.Mechanistically,RIP3 initiates OA by perturbing critical events,including cartilage metabolism,inflammatory re-sponses,senescence,and osteoclast differentiation.Clofibrate,a hypolipidemic drug,was identified as a novel RIP3 inhibitor that reverses ECM catabolism in OA.Conclusions:RIP3 is an essential governor of whole joint metabolic homeostasis by regulating both cartilage metabolism and subchondral bone remodeling.Reconstruction of the bone-cartilage unit by targeting RIP3 might provide a two-birds-one-stone approach for the development of future OA therapies.
