A full-length cDNA encoding fructose-6-phosphate, 2-kinase/fructose-2,6-bisphosphatase from maize (Zea mays L.) was cloned by the methods of reverse transcription-polymerase chain reaction (RT-PCR) and rapid amplifica...A full-length cDNA encoding fructose-6-phosphate, 2-kinase/fructose-2,6-bisphosphatase from maize (Zea mays L.) was cloned by the methods of reverse transcription-polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE), and designated as mF2KP. The encoded protein is composed of two regions. Its COOH-terminal region is catalytic region and homologous to the enzymes from other eukaryotes; and its NH 2-terminal region is common and special region only in plant. A truncated fragment of mF2KP covering integrated catalytic region was expressed in Escherichia coli. The fusion protein had the activities of fructose-6-phosphate, 2-kinase as well as fructose-2,6-bisphosphatase. Northern blot showed that the transcript level of mF2KP in seedlings initiated from strong-vigor seeds is lower than that from weak-vigor seeds.展开更多
Background The present study aimed to investigate the detailed mode and specific sites for their binding as well as the functional relevance of this binding in the phenotypic proliferation of vascular smooth muscle ce...Background The present study aimed to investigate the detailed mode and specific sites for their binding as well as the functional relevance of this binding in the phenotypic proliferation of vascular smooth muscle cells(SMCs). Methods CREG knocked-down SMCs were employed to evaluate the biological activity of wtCREG and mCREG.Expressions of SMC differentiation markers SM myosin heavy chain(SM-MHC),SM-actin,heavy caldesmon and myocardin were determined by Western blotting using specific antibodies. Cellular growth of SMCs was assessed by bromide dewuridine (BrdU) incorporation and cell cycle analysis on fluorescence-activated cell sorting(FACS).A solid-phase binding assay was used to study the binding of CREG to extracellular domains of M6P/IGF2R.The cellular co-localization of the two recombinant CREGs with M6P/IGF2R was detected on SMC surface by immunoprecipitation and immunofluorescence analysis.Results The molecular weight of wtCREG was around 30 kD while that of the mCREG was～25 kD.Treatment of wtCREG with PNGase F reduced its molecular weight from～30 kD to～25 kD,whereas PNGase F treatment had no effect on the molecular weight of mCREG.Both wtCREG and mCREG proteins enhanced SMC differentiation,inhibited BrdU incorporation,and arrested cell cycle progression when added to the culture medium.In CREG knocked-down SMCs,the amount of CREG detected by immunoblotting in M6P/IGF2R immunoprecipitates was significantly reduced when compared to normal cells.Both recombinant CREGs co-immunoprecipitated with M6P/IGF2R, although slightly reduced amount of the mutant CREG was detected in M6P/IGF2R immunoprecipitates.Immunostaining revealed that His-tagged CREGs co-localized with IGF2R on the cell surface in a glycosylation-independent manner.In vitro binding assay showed that CREGs bound to M6P/ IGF2R extracellular domains 7-10 and 11-13 in a glycosylation -dependent and -independent manner,respectively.Further blocking experiments using soluble M6P/IGF2R fragments and M6P/IGF2R neutralizing antibody indicated that the biological activities of recombinant CREGs in SMC growth and the up-regulation of SMC differentiation markers were all abolished by treatment with the M6P/IGF2R neutralizing antibody. However,although the growth inhibitory effect of wtCREG was nearly abolished by D7-10 or D11-13,the effect of mCREG was only reversed by Dll-13,indicating that the binding to domains 11-13 is required for CREG to modulate the proliferation of SMCs.Conclusions These data suggest that solubleCREG proteins can exert their biological function via binding to the extracellular domains 7-10 and 11-13 of cell surface M6P/IGF2R in both a glycosylation-dependent and -independent manner.展开更多
Objective:Cardiac remodeling is a common pathological change in various cardiovascular diseases and can ultimately result in heart failure.Thus,there is an urgent need for more effective strategies to aid in cardiac p...Objective:Cardiac remodeling is a common pathological change in various cardiovascular diseases and can ultimately result in heart failure.Thus,there is an urgent need for more effective strategies to aid in cardiac protection.Our previous work found that sphingosine-1-phosphate(S1P)could ameliorate cardiac hypertrophy.In this study,we aimed to investigate whether S1P could prevent cardiac fibrosis and the associated mechanisms in cardiac remodeling.Methods:Eight-week-old male C57BL/6 mice were randomly divided into a sham,transverse aortic constriction(TAC)or a TAC+S1P treatment group.Results:We found that S1P treatment improved cardiac function in TAC mice and that the cardiac fibrosis ratio in the TAC+S1P group was significantly lower and was accompanied by a decrease inα-smooth muscle actin(α-SMA)and collagen type I(COL I)expression compared with the TAC group.We also found that one of the key S1P enzymes,sphingosine kinase 2(SphK2),which was mainly distributed in cytoblasts,was downregulated in the cardiac remodeling case and recovered after S1P treatment in vivo and in vitro.In addition,our in vitro results showed that S1P treatment activated extracellular regulated protein kinases(ERK)phosphorylation mainly through the S1P receptor 2(S1PR2)and spurred p-ERK transposition from the cytoplasm to cytoblast in H9c2 cells exposed to phenylephrine.Conclusion:These findings suggest that SphK2 and the S1PR2/ERK pathway may participate in the anti-remodeling effect of S1P on the heart.This work therefore uncovers a novel potential therapy for the prevention of cardiac remodeling.展开更多
In this study, the effect of ascorbic acid 2-phosphate (Asc2P) was tested on porcine and rat mature hepatocytes in vitro. a). Asc2P increased the porcine, but not rat, albumin secretion and mRNA expression. The enhanc...In this study, the effect of ascorbic acid 2-phosphate (Asc2P) was tested on porcine and rat mature hepatocytes in vitro. a). Asc2P increased the porcine, but not rat, albumin secretion and mRNA expression. The enhancing effect of Asc2P on porcine C/EBP alpha mRNA was observed in porcine mature hepatocytes. These data suggested that Asc2P played an important role in the regulation of porcine albumin mRNA level. b). The enhancing effect of Asc2P on ammonium metabolic activity was also observed in porcine, but not rat, mature hepatocytes. The porcine ornithine transcarbamylase (OTC) and arginase mRNAs were augmented by Asc2P, indicating that Asc2P had a direct effect on the urea cycle. c). The porcine collagen type I and type III mRNA, but not type XII mRNA, were detected as well, sugessting that Asc2P did not have the effect on the non-parenchymal hepatocytes to induce collagen type I and III mRNA expression. d). Our RT-PCR analysis demonstrated that the porcine hepatocytes expressed the sodium-ascorbate co-transporters SVCT1 and SVCT2, however, the intensities of porcine sodium-ascorbate co-transporters SVCT1 and SVCT2 bands were not changed markedly. These findings indicated that the Asc2P had no effect on SVCT1 and SVCT2 mRNA expression. e). The enhancing effect of Asc2P on porcine albumin mRNA was inhibited by staurosporine, a portein kinase inhibitor. We conclude that the enhanced albumin mRNA by Asc2P might be due to activation of tyrosine protein kinase and/or PKC and the Asc2P enhanced porcine albumin mRNA mainly at the transcriptional step.展开更多
Degradation of oxidized or oxidatively modified proteins is an essential part of the cellular antioxidant defense system. 4-Hydroxy-2-nonenal (HNE), a major reactive aldehyde formed by lipid peroxidation, causes many ...Degradation of oxidized or oxidatively modified proteins is an essential part of the cellular antioxidant defense system. 4-Hydroxy-2-nonenal (HNE), a major reactive aldehyde formed by lipid peroxidation, causes many types of cellular damage. HNE-modified proteins are degraded by the ubiquitin-proteasome pathway or the lysosomal pathway. However, our previous studies using U937 cells showed that HNE-modified glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is degraded by cathepsin G. In the present study, we examined whether GAPDH in U937 cells treated with HNE in culture is degraded similarly to that incubated with HNE and U937 cell extract. Treatment with HNE for 10 min in culture decreased GAPDH activity in a concentration dependent manner, but did not affect GAPDH degradation. The proteasome activities were not affected by HNE, but culturing with HNE decreased cathepsin G activity and protein level in a concentration dependent manner. These results suggest that HNE-induced oxidative stress leads to decreased cathepsin G activity and results in the loss of GAPDH degradation. Taken together, our findings indicate that cathepsin G has an important role in the degradation of oxidatively modified GAPDH in U937 cells.展开更多
We recently reported that L-ascorbic acid 2-phosphate (AP) stimulates the growth of human dermal papilla (DP) cells, induces secretion of IGF-1 from the DP cells to promote hair shafts elongation in cultured human hai...We recently reported that L-ascorbic acid 2-phosphate (AP) stimulates the growth of human dermal papilla (DP) cells, induces secretion of IGF-1 from the DP cells to promote hair shafts elongation in cultured human hair follicles, and triggers early progression from the telogen to anagen phase in mice. Since the magnesium salt of AP (APMg) is a highly hydrophilic ionic molecule, it is not easy to deliver this reagent to the skin or hair follicles by topical application alone. In order to enhance skin penetration of APMg without changing any molecular properties, a non-invasive iontophoretic delivery method was introduced. Iontophoresis of the negatively charged APMg under the electrode bearing same charge (cathode) significantly enhanced the in vitro penetration of APMg into a Franz cell equipped with mouse dorsal skin. In contrast, iontophoretic movement with the anode inhibited APMg penetration achieved with passive diffusion alone. The effect of iontophoresis on enhancing the penetration of APMg was also found to be much higher in the skin of hairy mice (3 - 8 times) compared to hairless mice (1.5 - 2.5 times). These findings indicated that iontophoretic movement induced the transfollicular pathway more strongly and effectively than the transdermal pathway. This phenomena was also demonstrated by the in vivo iontophoretic delivery of sodium fluorescein using hairy and hairless mice. The degree of iontophoretic enhancement during APMg penetration was also dependent on various conditions such as current density and application duration.展开更多
The main active components of ginseng are ginsenosides,which play significant roles in treating cardiovascular diseases,cancer,and providing antioxidant effects.Ginsenosides are primarily synthesized through the mevalo...The main active components of ginseng are ginsenosides,which play significant roles in treating cardiovascular diseases,cancer,and providing antioxidant effects.Ginsenosides are primarily synthesized through the mevalo-nate pathway and the methylerythritol phosphate pathway.Many key enzyme genes involved in this biosynthetic process have been cloned and validated,yet the regulatory functions of transcription factors remain unclear.The C_(2)H_(2)-type zincfinger protein family,one of the largest families of transcription factors,is crucial in plant growth and development,response to biotic and abiotic stresses,and regulation of secondary metabolism.This study,based on the ginseng transcriptome database from Jilin,conducted a correlation analysis between the expression levels of PgZFPs genes in the Jilin ginseng C_(2)H_(2)-type zincfinger protein family and ginsenoside content,a gen-ome-wide association study of PgZFPs,and co-expression analysis of PgZFPs with validated key enzyme genes.Ultimately,five candidate genes involved in ginsenoside biosynthesis were identified.The involvement of PgZFP27 and PgZFP-59-02 genes from the PgZFPs family in the biosynthesis of ginsenosides was validated through in vitro methyl jasmonate(MeJA)induction experiments.This result provides new genetic resources for the biosynthesis of ginsenosides.展开更多
Colonic mucus and gut microbiota closely linked through mutual regulatory effect.While their alterations during sepsis and whether glutamine can maintain the colonic mucus barrier and gut microbiota stability are uncl...Colonic mucus and gut microbiota closely linked through mutual regulatory effect.While their alterations during sepsis and whether glutamine can maintain the colonic mucus barrier and gut microbiota stability are unclear.Cecal ligation and puncture-induced sepsis in mice was utilized to observe changes in colonic mucus,gut microbiota,and their interaction with glutamine intervention.Our findings indicated that glutamine mitigated sepsis-induced intestinal damage and restores colonic mucus barrier function by augmenting mucin synthesis.Further analysis revealed that goblet cells were under oxidative stress after sepsis,resulting in anterior gradient-2(AGR2),the key mucin-modifying enzyme,being dissynthesized,and inhibiting mucin 2(MUC2)maturation.Glutamine could ameliorates this situation by promoting the key enzyme glucose-6-phosphate dehydrogenase(G6PD)glycosylation in the pentose phosphate pathway,increasing the reduced nicotinamide adenine dinucleotide phosphate(NADPH)synthesis,reducing endoplasmic reticulum stress,and accelerating AGR2 synthesis and MUC2 maturation.Additionally,glutamine aided in maintaining gut microbiota stability during sepsis,up-regulating mucin-associated bacteria such as Akkermansia and Alistipes.These bacteria,intimately linked to mucin synthesis and degradation,may impact intestinal mucus stability.In conclusion,glutamine can maintain goblet cell redox balance,promotes AGR2 synthesis and MUC2 maturation,shields the mucus barrier,and potentially maintains gut microbiota stability by regulating the interaction between bacteria and mucus,thus alleviating sepsis-induced intestinal damage.展开更多
AIM:To investigate the relationship between loss of heterozygosity (LOH) for mannose 6-phosphate/insulin- like growth factor 2 receptor (M6P/IGF2R) and the outcomes for primary HCC patients treated with partial hepate...AIM:To investigate the relationship between loss of heterozygosity (LOH) for mannose 6-phosphate/insulin- like growth factor 2 receptor (M6P/IGF2R) and the outcomes for primary HCC patients treated with partial hepatectomy. METHODS: The LOH for M6P/IGF2R in primary HCC patients was assessed using six different gene-specific nucleotide polymorphisms. The patients studied were enrolled to undergo partial hepatectomy. RESULTS: M6P/IGF2R was found to be polymorphic in 73.3% (22/30) of the patients, and of these patients, 50.0% (11/22) had tumors showing LOH in M6P/IGF2R. Loss of heterozygosity in M6P/IGF2R was associated with significant reductions in the two year overall survival rate (24.9% vs 65.5%; P = 0.04) and the disease-free survival rate (17.8% vs 59.3%; P = 0.03). CONCLUSION: These results show M6P/IGF2R LOH predicts poor clinical outcomes in surgically resected primary HCC patients.展开更多
AIM: To examine the expression of SphK1, an oncogenic kinase that produces sphingosine 1-phosphate (S1P), and its correlation with the expression of LPAR2, a major lysophosphatidic acid (LPA) receptor overexpressed in...AIM: To examine the expression of SphK1, an oncogenic kinase that produces sphingosine 1-phosphate (S1P), and its correlation with the expression of LPAR2, a major lysophosphatidic acid (LPA) receptor overexpressed in various cancers, in human colorectal cancer.METHODS: Real-time reverse-transcription polymerase chain reaction was used to measure the mRNA expression of SphK1, LPAR2, and the three major S1P receptors in 27 colorectal cancer samples and corresponding normal tissue samples. We also examined the correlation between the expression of SphK1 and LPAR2.RESULTS: Colorectal cancer tissue in 22 of 27 patients had higher levels of SphK1 mRNA than in normal tissue. In two-thirds of the samples, SphK1 mRNA expression was more than two-fold higher than in normal tissue. Consistent with previous reports, LPAR2 mRNA expression in 20 of 27 colorectal cancer tissue samples was higher compared to normal tissue samples. Expression profiles of all three major S1P receptors, S1PR1, S1PR2, and S1PR3, varied without any trend, with no significant difference in expression between cancer and normal tissues. A highly significant positive correlation was found between SphK1 and LPAR2 expression [Pearson’s correlation coefficient (r) = 0.784 and P < 0.01]. The mRNA levels of SphK1 and LPAR2 did not correlate with TNM stage.CONCLUSION: Our findings suggest that S1P and LPA may play important roles in the development of colorectal cancer via the upregulation of SphK1 and LPAR2, both of which could serve as new therapeutic targets in the treatment of colorectal cancer.展开更多
Galactosemia is an autosomal recessive disorder caused by deficient or absent activities of one of the three enzymes involved in the galactose metabolic pathway. The predominant form is classic type galactosemia cause...Galactosemia is an autosomal recessive disorder caused by deficient or absent activities of one of the three enzymes involved in the galactose metabolic pathway. The predominant form is classic type galactosemia caused by severe reduction or absence of the galactose- 1-phosphate uridyl transferase (GALT) enzyme. Coexistence of extrahepatic biliary atresia (EHBA) with Duarte 1 and 2 variants of galactosemia has not been described earlier. Here we report a case of EHBA with concordant Duarte 1 and 2 variants of galactosemia in an infant with cholestasis. Genetic analysis of the index patient for galactosemia revealed presence of Duarte 1/Duarte 2 variants of galactosemia with genotype N314D-L218L/N314D-G1105C-GI391A- G1323A-5’UTR-119delGTCA. Clinical evaluation of the patient showed the presence of EHBA. Henceforth, it may be hypothesized that EHBA may have a genetic basis with simultaneous involvement of the GALT gene.展开更多
Objective Glutamine fructose-6-phosphate transaminase 2(GFPT2)is involved in a wide range of biological functions in human cancer.However,few studies have comprehensively analyzed the correlation between GFPT2 and dif...Objective Glutamine fructose-6-phosphate transaminase 2(GFPT2)is involved in a wide range of biological functions in human cancer.However,few studies have comprehensively analyzed the correlation between GFPT2 and different cancer prognoses and tumor microenvironments(TMEs).Methods We evaluated the expression level and prognostic value of GFPT2 using updated public databases and multiple comprehensive bioinformatics analysis methods and explored the relationship between GFPT2 expression and immune infiltration,immune neoantigens,tumor mutational burden(TMB),and microsatellite instability in pan-cancer.Results GFPT2 was highly expressed in five cancers.GFPT2 expression correlates with the prognosis of several cancers from The Cancer Genome Atlas(TCGA)and is significantly associated with stromal and immune scores in pan-cancer.High GFPT2 expression in BLCA,BRCA,and CHOL was positively correlated with the infiltration of immune cells,such as B-cells,CD4+T,CD8+T cells,dendritic cells,neutrophils,and macrophages.Conclusion High GFPT2 expression may modify the outcomes of patients with BLCA,BRCA,or CHOL cancers by increasing immune cell infiltration.These findings may provide insights for further investigation into GFPT2 as a potential target in pan-cancer.展开更多
Plant isoprenoids are formed from precursors synthesized by the mevalonate （MVA） pathway in the cytosol or by the methyl-D-erythritol 4-phosphate （MEP） pathway in plastids. Although some exchange of precursors occ...Plant isoprenoids are formed from precursors synthesized by the mevalonate （MVA） pathway in the cytosol or by the methyl-D-erythritol 4-phosphate （MEP） pathway in plastids. Although some exchange of precursors occurs, cytosolic sesquiterpenes are assumed to derive mainly from MVA, while plastidial monoterpenes are produced preferentially from MEP precursors. Additional complexity arises in the first step of the MEP pathway, which is typically catalyzed by two divergent 1-deoxy-D-xylulose 5-phosphate synthase isoforms （DXS1, DXS2）. In tomato （Solanum lycopersicum）, the SIDXS1 gene is ubiquitously expressed with highest levels during fruit ripening, whereas SIDXS2 transcripts are abundant in only few tissues, including young leaves, petals, and isolated trichomes. Specific down-regulation of SIDXS2 expression was performed by RNA interference in transgenic plants to investigate feedback mechanisms. SIDXS2 down-regulation led to a decrease in the monoterpene β-phellandrene and an increase in two sesquiterpenes in trichomes. Moreover, incorporation of MVA-derived precursors into residual monoterpenes and into sesquiterpenes was elevated as determined by comparison of ^13C to ^12C natural isotope ratios. A compensatory up-regulation of SIDXS1 was not observed. Down-regulated lines also exhibited increased trichome density and showed less damage by leaf-feeding Spodoptera littoralis caterpillars. The results reveal novel, non-redundant roles of DXS2 in modulating isoprenoid metabolism and a pronounced plasticity in isoprenoid precursor allocation.展开更多
Genome-wide and candidate gene association studies have identified several variants that predispose indi- viduals to developing nonalcoholic fatty liver disease （NAFLD）. However, the gene that has been consis- tentl...Genome-wide and candidate gene association studies have identified several variants that predispose indi- viduals to developing nonalcoholic fatty liver disease （NAFLD）. However, the gene that has been consis- tently involved in the genetic susceptibility of NAFLD in humans is patatin-like phospholipase domain contain- ing 3 （PNPLA3, also known as adiponutrin）. A nonsyn- onymous single nucleotide polymorphism in PNPLA3 （rs738409 C/G, a coding variant that encodes an amino acid substitution I148M） is significantly associated with fatty liver and histological disease severity, not only in adults but also in children. Nevertheless, how PNPLA3 influences the biology of fatty liver disease is still an open question. A recent article describes new aspects about PNPLA3 gene/protein function and suggests that the I148M variant promotes hepatic lipid synthesis due to a gain of function. We revise here the published data about the role of the I148M variant in lipogen- esis/lipolysis, and suggest putative areas of future research. For instance we explored in silico whether the rs738409 C or G alleles have the ability to modify miRNA binding sites and miRNA gene regulation, and we found that prediction of PNPLA3 target miRNAs shows two miRNAs potentially interacting in the 3＇ UTR region （hsa-miR-769-3p and hsa-miR-516a-3p）. In addition, interesting unanswered questions remain to be explored. For example, PNPLA3 lies between two CCCTC-binding factor-bound sites that could be tested for insulator activity, and an intronic histone 3 lysine 4 trimethylation peak predicts an enhancer element, cor- roborated by the DNase I hypersensitivity site peak. Finally, an interaction between PNPLA3 and glycerol- 3-phosphate acyltransferase 2 is suggested by data miming.展开更多
The liver is the central organ involved in lipid metabolism and the gastrointestinal(GI)tract is responsible for nutrient absorption and partitioning.Obesity,dyslipidemia and metabolic disorders are of increasing publ...The liver is the central organ involved in lipid metabolism and the gastrointestinal(GI)tract is responsible for nutrient absorption and partitioning.Obesity,dyslipidemia and metabolic disorders are of increasing public health concern worldwide,and novel therapeutics that target both the liver and the GI tract(gut-liver axis)are much needed.In addition to aiding fat digestion,bile acids act as important signaling molecules that regulate lipid,glucose and energy metabolism via activating nuclear receptor,G protein-coupled receptors(GPCRs),Takeda G protein receptor 5(TGR5)and sphingosine-1-phosphate receptor 2(S1PR2).Sphingosine-1-phosphate(S1P)is synthesized by two sphingosine kinase isoforms and is a potent signaling molecule that plays a critical role in various diseases such as fatty liver,in-flammatory bowel disease(IBD)and colorectal cancer.In this review,we will focus on recent findings related to the role of S1P-mediated signaling pathways in the gut-liver axis.展开更多
Mangoes (Mangifera indica L.) are one of the most important tropical foods. The seed is one of the main by-products of mango processing. Therefore, it is important to find an economically viable use for this waste (e....Mangoes (Mangifera indica L.) are one of the most important tropical foods. The seed is one of the main by-products of mango processing. Therefore, it is important to find an economically viable use for this waste (e.g., as a food additive or supplement with high nutraceutical value). We investigated the anti-obesity effects of mango seed kernel extract with hot water (MSKE-W) in 3T3-L1 adipocytes and in a high fat diet (HFD)-induced obesity rat model. MSKE-W caused a significant decrease in the activity of glycerol 2-phosphate dehydrogenase in 3T3-L1 adipocytes without eliciting cell cytotoxicity and inhibited cellular lipid accumulation through down-regulation of transcription factors such as PPARγ and C/EBPα. In the animal model, rats fed an HFD containing 1% MSKE-W gained less weight than rats fed an HFD alone. The visceral fat mass in rats fed an HFD containing 1% MSKE-W tended to be lower than that in rats fed an HFD alone. Furthermore, histological examination of rat livers from an HFD showed steatohepatitis. However, rats on an HFD containning 1% MSKE-W showed no histopathological changes in liver tissue. Our results indicate that MSKE-W influences anti-obesity effects, both in vitro and in vivo, and suggest that MSKE-W provides a novel preventive potential against obesity.展开更多
The mechanisms underlying autophagic defects in nonalcoholic steatohepatitis(NASH)remain largely unknown.We aimed to elucidate the roles of hepatic cyclooxygenase 1(COX1)in autophagy and the pathogenesis of diet-induc...The mechanisms underlying autophagic defects in nonalcoholic steatohepatitis(NASH)remain largely unknown.We aimed to elucidate the roles of hepatic cyclooxygenase 1(COX1)in autophagy and the pathogenesis of diet-induced steatohepatitis in mice.Human nonalcoholic fatty liver disease(NAFLD)liver samples were used to examine the protein expression of COX1 and the level of autophagy.Cox1^(Δhepa)mice and their wildtype littermates were generated and fed with 3 different NASH models.We found that hepatic COX1 expression was increased in patients with NASH and diet induced NASH mice models accompanied by impaired autophagy.COX1 was required for basal autophagy in hepatocytes and liver specific COX1 deletion exacerbated steatohepatitis by inhibiting autophagy.Mechanistically,COX1 directly interacted with WD repeat domain,phosphoinositide interacting 2(WIPI2),which was crucial for autophagosome maturation.Adeno-associated virus(AAV)-mediated rescue of WIPI2 reversed the impaired autophagic flux and improved NASH phenotypes in Cox1^(Δhepa)mice,indicating that COX1 deletion-mediated steatohepatitis was partially dependent on WIPI2-mediated autophagy.In conclusion,we demonstrated a novel role of COX1 in hepatic autophagy that protected against NASH by interacting with WIPI2.Targeting the COX1 WIPI2 axis may be a novel therapeutic strategy for NASH.展开更多
Bile acids(BA)are synthesized from cholesterol in the liver.They are essential for promotion of the absorption of lipids,cholesterol,and lipid-soluble vitamins from the intestines.BAs are hormones that regulate nutrie...Bile acids(BA)are synthesized from cholesterol in the liver.They are essential for promotion of the absorption of lipids,cholesterol,and lipid-soluble vitamins from the intestines.BAs are hormones that regulate nutrient metabolism by activating nuclear receptors(farnesoid X receptor(FXR),pregnane X receptor,vitamin D)and G protein-coupled receptors(e.g.,TGR5,sphingosine-1-phosphate receptor 2(S1PR2))in the liver and intestines.In the liver,S1PR2 activation by conjugated BAs activates the extracellular signal-regulated kinase 1/2 and AKT signaling pathways,and nuclear sphingosine kinase 2.The latter produces sphingosine-1-phosphate(S1P),an inhibitor of histone deacetylases 1/2,which allows for the differential up-regulation of expression of genes involved in the metabolism of sterols and lipids.We discuss here the emerging concepts of the interactions of BAs,FXR,insulin,S1P signaling and nutrient metabolism.展开更多
Over 20%of mortality during acute liver failure is associated with the development of hepatic encephalopathy(HE).Thus,HE is a complication of acute liver failure with a broad spectrum of neuropsychiatric abnormalities...Over 20%of mortality during acute liver failure is associated with the development of hepatic encephalopathy(HE).Thus,HE is a complication of acute liver failure with a broad spectrum of neuropsychiatric abnormalities ranging from subclinical alterations to coma.HE is caused by the diversion of portal blood into systemic circulation through portosystemic collateral vessels.Thus,the brain is exposed to intestinal-derived toxic substances.Moreover,the strategies to prevent advancement and improve the prognosis of such a liver-brain disease rely on intestinal microbial modulation.This is supported by the findings that antibiotics such as rifaximin and laxative lactulose can alleviate hepatic cirrhosis and/or prevent HE.Together,the significance of the gut-liver-brain axis in human health warrants attention.This review paper focuses on the roles of bacteria metabolites,mainly ammonia and bile acids(BAs)as well as BA receptors in HE.The literature search conducted for this review included searches for phrases such as BA receptors,BAs,ammonia,farnesoid X receptor(FXR),G protein-coupled bile acid receptor 1(GPBAR1 or TGR5),sphingosine-1-phosphate receptor 2(S1PR2),and cirrhosis in conjunction with the phrase hepatic encephalopathy and portosystemic encephalopathy.PubMed,as well as Google Scholar,was the search engines used to find relevant publications.展开更多
文摘A full-length cDNA encoding fructose-6-phosphate, 2-kinase/fructose-2,6-bisphosphatase from maize (Zea mays L.) was cloned by the methods of reverse transcription-polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE), and designated as mF2KP. The encoded protein is composed of two regions. Its COOH-terminal region is catalytic region and homologous to the enzymes from other eukaryotes; and its NH 2-terminal region is common and special region only in plant. A truncated fragment of mF2KP covering integrated catalytic region was expressed in Escherichia coli. The fusion protein had the activities of fructose-6-phosphate, 2-kinase as well as fructose-2,6-bisphosphatase. Northern blot showed that the transcript level of mF2KP in seedlings initiated from strong-vigor seeds is lower than that from weak-vigor seeds.
文摘Background The present study aimed to investigate the detailed mode and specific sites for their binding as well as the functional relevance of this binding in the phenotypic proliferation of vascular smooth muscle cells(SMCs). Methods CREG knocked-down SMCs were employed to evaluate the biological activity of wtCREG and mCREG.Expressions of SMC differentiation markers SM myosin heavy chain(SM-MHC),SM-actin,heavy caldesmon and myocardin were determined by Western blotting using specific antibodies. Cellular growth of SMCs was assessed by bromide dewuridine (BrdU) incorporation and cell cycle analysis on fluorescence-activated cell sorting(FACS).A solid-phase binding assay was used to study the binding of CREG to extracellular domains of M6P/IGF2R.The cellular co-localization of the two recombinant CREGs with M6P/IGF2R was detected on SMC surface by immunoprecipitation and immunofluorescence analysis.Results The molecular weight of wtCREG was around 30 kD while that of the mCREG was～25 kD.Treatment of wtCREG with PNGase F reduced its molecular weight from～30 kD to～25 kD,whereas PNGase F treatment had no effect on the molecular weight of mCREG.Both wtCREG and mCREG proteins enhanced SMC differentiation,inhibited BrdU incorporation,and arrested cell cycle progression when added to the culture medium.In CREG knocked-down SMCs,the amount of CREG detected by immunoblotting in M6P/IGF2R immunoprecipitates was significantly reduced when compared to normal cells.Both recombinant CREGs co-immunoprecipitated with M6P/IGF2R, although slightly reduced amount of the mutant CREG was detected in M6P/IGF2R immunoprecipitates.Immunostaining revealed that His-tagged CREGs co-localized with IGF2R on the cell surface in a glycosylation-independent manner.In vitro binding assay showed that CREGs bound to M6P/ IGF2R extracellular domains 7-10 and 11-13 in a glycosylation -dependent and -independent manner,respectively.Further blocking experiments using soluble M6P/IGF2R fragments and M6P/IGF2R neutralizing antibody indicated that the biological activities of recombinant CREGs in SMC growth and the up-regulation of SMC differentiation markers were all abolished by treatment with the M6P/IGF2R neutralizing antibody. However,although the growth inhibitory effect of wtCREG was nearly abolished by D7-10 or D11-13,the effect of mCREG was only reversed by Dll-13,indicating that the binding to domains 11-13 is required for CREG to modulate the proliferation of SMCs.Conclusions These data suggest that solubleCREG proteins can exert their biological function via binding to the extracellular domains 7-10 and 11-13 of cell surface M6P/IGF2R in both a glycosylation-dependent and -independent manner.
基金supported by the National Natural Science Foundation of China(No.81873505).
文摘Objective:Cardiac remodeling is a common pathological change in various cardiovascular diseases and can ultimately result in heart failure.Thus,there is an urgent need for more effective strategies to aid in cardiac protection.Our previous work found that sphingosine-1-phosphate(S1P)could ameliorate cardiac hypertrophy.In this study,we aimed to investigate whether S1P could prevent cardiac fibrosis and the associated mechanisms in cardiac remodeling.Methods:Eight-week-old male C57BL/6 mice were randomly divided into a sham,transverse aortic constriction(TAC)or a TAC+S1P treatment group.Results:We found that S1P treatment improved cardiac function in TAC mice and that the cardiac fibrosis ratio in the TAC+S1P group was significantly lower and was accompanied by a decrease inα-smooth muscle actin(α-SMA)and collagen type I(COL I)expression compared with the TAC group.We also found that one of the key S1P enzymes,sphingosine kinase 2(SphK2),which was mainly distributed in cytoblasts,was downregulated in the cardiac remodeling case and recovered after S1P treatment in vivo and in vitro.In addition,our in vitro results showed that S1P treatment activated extracellular regulated protein kinases(ERK)phosphorylation mainly through the S1P receptor 2(S1PR2)and spurred p-ERK transposition from the cytoplasm to cytoblast in H9c2 cells exposed to phenylephrine.Conclusion:These findings suggest that SphK2 and the S1PR2/ERK pathway may participate in the anti-remodeling effect of S1P on the heart.This work therefore uncovers a novel potential therapy for the prevention of cardiac remodeling.
文摘In this study, the effect of ascorbic acid 2-phosphate (Asc2P) was tested on porcine and rat mature hepatocytes in vitro. a). Asc2P increased the porcine, but not rat, albumin secretion and mRNA expression. The enhancing effect of Asc2P on porcine C/EBP alpha mRNA was observed in porcine mature hepatocytes. These data suggested that Asc2P played an important role in the regulation of porcine albumin mRNA level. b). The enhancing effect of Asc2P on ammonium metabolic activity was also observed in porcine, but not rat, mature hepatocytes. The porcine ornithine transcarbamylase (OTC) and arginase mRNAs were augmented by Asc2P, indicating that Asc2P had a direct effect on the urea cycle. c). The porcine collagen type I and type III mRNA, but not type XII mRNA, were detected as well, sugessting that Asc2P did not have the effect on the non-parenchymal hepatocytes to induce collagen type I and III mRNA expression. d). Our RT-PCR analysis demonstrated that the porcine hepatocytes expressed the sodium-ascorbate co-transporters SVCT1 and SVCT2, however, the intensities of porcine sodium-ascorbate co-transporters SVCT1 and SVCT2 bands were not changed markedly. These findings indicated that the Asc2P had no effect on SVCT1 and SVCT2 mRNA expression. e). The enhancing effect of Asc2P on porcine albumin mRNA was inhibited by staurosporine, a portein kinase inhibitor. We conclude that the enhanced albumin mRNA by Asc2P might be due to activation of tyrosine protein kinase and/or PKC and the Asc2P enhanced porcine albumin mRNA mainly at the transcriptional step.
文摘Degradation of oxidized or oxidatively modified proteins is an essential part of the cellular antioxidant defense system. 4-Hydroxy-2-nonenal (HNE), a major reactive aldehyde formed by lipid peroxidation, causes many types of cellular damage. HNE-modified proteins are degraded by the ubiquitin-proteasome pathway or the lysosomal pathway. However, our previous studies using U937 cells showed that HNE-modified glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is degraded by cathepsin G. In the present study, we examined whether GAPDH in U937 cells treated with HNE in culture is degraded similarly to that incubated with HNE and U937 cell extract. Treatment with HNE for 10 min in culture decreased GAPDH activity in a concentration dependent manner, but did not affect GAPDH degradation. The proteasome activities were not affected by HNE, but culturing with HNE decreased cathepsin G activity and protein level in a concentration dependent manner. These results suggest that HNE-induced oxidative stress leads to decreased cathepsin G activity and results in the loss of GAPDH degradation. Taken together, our findings indicate that cathepsin G has an important role in the degradation of oxidatively modified GAPDH in U937 cells.
文摘We recently reported that L-ascorbic acid 2-phosphate (AP) stimulates the growth of human dermal papilla (DP) cells, induces secretion of IGF-1 from the DP cells to promote hair shafts elongation in cultured human hair follicles, and triggers early progression from the telogen to anagen phase in mice. Since the magnesium salt of AP (APMg) is a highly hydrophilic ionic molecule, it is not easy to deliver this reagent to the skin or hair follicles by topical application alone. In order to enhance skin penetration of APMg without changing any molecular properties, a non-invasive iontophoretic delivery method was introduced. Iontophoresis of the negatively charged APMg under the electrode bearing same charge (cathode) significantly enhanced the in vitro penetration of APMg into a Franz cell equipped with mouse dorsal skin. In contrast, iontophoretic movement with the anode inhibited APMg penetration achieved with passive diffusion alone. The effect of iontophoresis on enhancing the penetration of APMg was also found to be much higher in the skin of hairy mice (3 - 8 times) compared to hairless mice (1.5 - 2.5 times). These findings indicated that iontophoretic movement induced the transfollicular pathway more strongly and effectively than the transdermal pathway. This phenomena was also demonstrated by the in vivo iontophoretic delivery of sodium fluorescein using hairy and hairless mice. The degree of iontophoretic enhancement during APMg penetration was also dependent on various conditions such as current density and application duration.
基金This work was supported by the Department of Science and Technology of Jilin Province(20240101227JC,20210402043GH,20200801063GH,20190201264JC,20190103104JH,20180414077GH,and 20180101027JC)the Development and Reform Commission of Jilin Province(2016C064 and 2018C047-3).
文摘The main active components of ginseng are ginsenosides,which play significant roles in treating cardiovascular diseases,cancer,and providing antioxidant effects.Ginsenosides are primarily synthesized through the mevalo-nate pathway and the methylerythritol phosphate pathway.Many key enzyme genes involved in this biosynthetic process have been cloned and validated,yet the regulatory functions of transcription factors remain unclear.The C_(2)H_(2)-type zincfinger protein family,one of the largest families of transcription factors,is crucial in plant growth and development,response to biotic and abiotic stresses,and regulation of secondary metabolism.This study,based on the ginseng transcriptome database from Jilin,conducted a correlation analysis between the expression levels of PgZFPs genes in the Jilin ginseng C_(2)H_(2)-type zincfinger protein family and ginsenoside content,a gen-ome-wide association study of PgZFPs,and co-expression analysis of PgZFPs with validated key enzyme genes.Ultimately,five candidate genes involved in ginsenoside biosynthesis were identified.The involvement of PgZFP27 and PgZFP-59-02 genes from the PgZFPs family in the biosynthesis of ginsenosides was validated through in vitro methyl jasmonate(MeJA)induction experiments.This result provides new genetic resources for the biosynthesis of ginsenosides.
基金supported by the National Natural Science Foundation of China(82172202)Innovative Leading Talents Project of Chongqing(cstc2022ycjh-bgzxm0148)+1 种基金the Project of NINGBO Leading Medical&Health Discipline(2022-F17)Ningbo Top Medical and Health Research Program(2023030615).
文摘Colonic mucus and gut microbiota closely linked through mutual regulatory effect.While their alterations during sepsis and whether glutamine can maintain the colonic mucus barrier and gut microbiota stability are unclear.Cecal ligation and puncture-induced sepsis in mice was utilized to observe changes in colonic mucus,gut microbiota,and their interaction with glutamine intervention.Our findings indicated that glutamine mitigated sepsis-induced intestinal damage and restores colonic mucus barrier function by augmenting mucin synthesis.Further analysis revealed that goblet cells were under oxidative stress after sepsis,resulting in anterior gradient-2(AGR2),the key mucin-modifying enzyme,being dissynthesized,and inhibiting mucin 2(MUC2)maturation.Glutamine could ameliorates this situation by promoting the key enzyme glucose-6-phosphate dehydrogenase(G6PD)glycosylation in the pentose phosphate pathway,increasing the reduced nicotinamide adenine dinucleotide phosphate(NADPH)synthesis,reducing endoplasmic reticulum stress,and accelerating AGR2 synthesis and MUC2 maturation.Additionally,glutamine aided in maintaining gut microbiota stability during sepsis,up-regulating mucin-associated bacteria such as Akkermansia and Alistipes.These bacteria,intimately linked to mucin synthesis and degradation,may impact intestinal mucus stability.In conclusion,glutamine can maintain goblet cell redox balance,promotes AGR2 synthesis and MUC2 maturation,shields the mucus barrier,and potentially maintains gut microbiota stability by regulating the interaction between bacteria and mucus,thus alleviating sepsis-induced intestinal damage.
基金The Special Clinical Fund of Gyeongsang National University Hospital
文摘AIM:To investigate the relationship between loss of heterozygosity (LOH) for mannose 6-phosphate/insulin- like growth factor 2 receptor (M6P/IGF2R) and the outcomes for primary HCC patients treated with partial hepatectomy. METHODS: The LOH for M6P/IGF2R in primary HCC patients was assessed using six different gene-specific nucleotide polymorphisms. The patients studied were enrolled to undergo partial hepatectomy. RESULTS: M6P/IGF2R was found to be polymorphic in 73.3% (22/30) of the patients, and of these patients, 50.0% (11/22) had tumors showing LOH in M6P/IGF2R. Loss of heterozygosity in M6P/IGF2R was associated with significant reductions in the two year overall survival rate (24.9% vs 65.5%; P = 0.04) and the disease-free survival rate (17.8% vs 59.3%; P = 0.03). CONCLUSION: These results show M6P/IGF2R LOH predicts poor clinical outcomes in surgically resected primary HCC patients.
基金Supported by Grant 2010 from Tokyo MetropolisJapan
文摘AIM: To examine the expression of SphK1, an oncogenic kinase that produces sphingosine 1-phosphate (S1P), and its correlation with the expression of LPAR2, a major lysophosphatidic acid (LPA) receptor overexpressed in various cancers, in human colorectal cancer.METHODS: Real-time reverse-transcription polymerase chain reaction was used to measure the mRNA expression of SphK1, LPAR2, and the three major S1P receptors in 27 colorectal cancer samples and corresponding normal tissue samples. We also examined the correlation between the expression of SphK1 and LPAR2.RESULTS: Colorectal cancer tissue in 22 of 27 patients had higher levels of SphK1 mRNA than in normal tissue. In two-thirds of the samples, SphK1 mRNA expression was more than two-fold higher than in normal tissue. Consistent with previous reports, LPAR2 mRNA expression in 20 of 27 colorectal cancer tissue samples was higher compared to normal tissue samples. Expression profiles of all three major S1P receptors, S1PR1, S1PR2, and S1PR3, varied without any trend, with no significant difference in expression between cancer and normal tissues. A highly significant positive correlation was found between SphK1 and LPAR2 expression [Pearson’s correlation coefficient (r) = 0.784 and P < 0.01]. The mRNA levels of SphK1 and LPAR2 did not correlate with TNM stage.CONCLUSION: Our findings suggest that S1P and LPA may play important roles in the development of colorectal cancer via the upregulation of SphK1 and LPAR2, both of which could serve as new therapeutic targets in the treatment of colorectal cancer.
文摘Galactosemia is an autosomal recessive disorder caused by deficient or absent activities of one of the three enzymes involved in the galactose metabolic pathway. The predominant form is classic type galactosemia caused by severe reduction or absence of the galactose- 1-phosphate uridyl transferase (GALT) enzyme. Coexistence of extrahepatic biliary atresia (EHBA) with Duarte 1 and 2 variants of galactosemia has not been described earlier. Here we report a case of EHBA with concordant Duarte 1 and 2 variants of galactosemia in an infant with cholestasis. Genetic analysis of the index patient for galactosemia revealed presence of Duarte 1/Duarte 2 variants of galactosemia with genotype N314D-L218L/N314D-G1105C-GI391A- G1323A-5’UTR-119delGTCA. Clinical evaluation of the patient showed the presence of EHBA. Henceforth, it may be hypothesized that EHBA may have a genetic basis with simultaneous involvement of the GALT gene.
基金Supported by a grant from the National Natural Science Foundation of China(No.81700256).
文摘Objective Glutamine fructose-6-phosphate transaminase 2(GFPT2)is involved in a wide range of biological functions in human cancer.However,few studies have comprehensively analyzed the correlation between GFPT2 and different cancer prognoses and tumor microenvironments(TMEs).Methods We evaluated the expression level and prognostic value of GFPT2 using updated public databases and multiple comprehensive bioinformatics analysis methods and explored the relationship between GFPT2 expression and immune infiltration,immune neoantigens,tumor mutational burden(TMB),and microsatellite instability in pan-cancer.Results GFPT2 was highly expressed in five cancers.GFPT2 expression correlates with the prognosis of several cancers from The Cancer Genome Atlas(TCGA)and is significantly associated with stromal and immune scores in pan-cancer.High GFPT2 expression in BLCA,BRCA,and CHOL was positively correlated with the infiltration of immune cells,such as B-cells,CD4+T,CD8+T cells,dendritic cells,neutrophils,and macrophages.Conclusion High GFPT2 expression may modify the outcomes of patients with BLCA,BRCA,or CHOL cancers by increasing immune cell infiltration.These findings may provide insights for further investigation into GFPT2 as a potential target in pan-cancer.
文摘Plant isoprenoids are formed from precursors synthesized by the mevalonate （MVA） pathway in the cytosol or by the methyl-D-erythritol 4-phosphate （MEP） pathway in plastids. Although some exchange of precursors occurs, cytosolic sesquiterpenes are assumed to derive mainly from MVA, while plastidial monoterpenes are produced preferentially from MEP precursors. Additional complexity arises in the first step of the MEP pathway, which is typically catalyzed by two divergent 1-deoxy-D-xylulose 5-phosphate synthase isoforms （DXS1, DXS2）. In tomato （Solanum lycopersicum）, the SIDXS1 gene is ubiquitously expressed with highest levels during fruit ripening, whereas SIDXS2 transcripts are abundant in only few tissues, including young leaves, petals, and isolated trichomes. Specific down-regulation of SIDXS2 expression was performed by RNA interference in transgenic plants to investigate feedback mechanisms. SIDXS2 down-regulation led to a decrease in the monoterpene β-phellandrene and an increase in two sesquiterpenes in trichomes. Moreover, incorporation of MVA-derived precursors into residual monoterpenes and into sesquiterpenes was elevated as determined by comparison of ^13C to ^12C natural isotope ratios. A compensatory up-regulation of SIDXS1 was not observed. Down-regulated lines also exhibited increased trichome density and showed less damage by leaf-feeding Spodoptera littoralis caterpillars. The results reveal novel, non-redundant roles of DXS2 in modulating isoprenoid metabolism and a pronounced plasticity in isoprenoid precursor allocation.
基金Supported by Grants PICT 2008-1521 and PICT 2010 0441,from National Agency for Science and TechnologyUBACYT CM04,from Universidad de Buenos AiresSookoian S and Pirola CJ belong to National Council of Scientific and Technical Research
文摘Genome-wide and candidate gene association studies have identified several variants that predispose indi- viduals to developing nonalcoholic fatty liver disease （NAFLD）. However, the gene that has been consis- tently involved in the genetic susceptibility of NAFLD in humans is patatin-like phospholipase domain contain- ing 3 （PNPLA3, also known as adiponutrin）. A nonsyn- onymous single nucleotide polymorphism in PNPLA3 （rs738409 C/G, a coding variant that encodes an amino acid substitution I148M） is significantly associated with fatty liver and histological disease severity, not only in adults but also in children. Nevertheless, how PNPLA3 influences the biology of fatty liver disease is still an open question. A recent article describes new aspects about PNPLA3 gene/protein function and suggests that the I148M variant promotes hepatic lipid synthesis due to a gain of function. We revise here the published data about the role of the I148M variant in lipogen- esis/lipolysis, and suggest putative areas of future research. For instance we explored in silico whether the rs738409 C or G alleles have the ability to modify miRNA binding sites and miRNA gene regulation, and we found that prediction of PNPLA3 target miRNAs shows two miRNAs potentially interacting in the 3＇ UTR region （hsa-miR-769-3p and hsa-miR-516a-3p）. In addition, interesting unanswered questions remain to be explored. For example, PNPLA3 lies between two CCCTC-binding factor-bound sites that could be tested for insulator activity, and an intronic histone 3 lysine 4 trimethylation peak predicts an enhancer element, cor- roborated by the DNase I hypersensitivity site peak. Finally, an interaction between PNPLA3 and glycerol- 3-phosphate acyltransferase 2 is suggested by data miming.
基金This work was supported by the USA National Institutes of Health(NIH)grants R01 DK104893 and R01DK-057543VA Merit Award I01BX004033 and 1I01BX001390Research Career Scientist Award(IK6BX004477)from the Department of Veterans Affairs.
文摘The liver is the central organ involved in lipid metabolism and the gastrointestinal(GI)tract is responsible for nutrient absorption and partitioning.Obesity,dyslipidemia and metabolic disorders are of increasing public health concern worldwide,and novel therapeutics that target both the liver and the GI tract(gut-liver axis)are much needed.In addition to aiding fat digestion,bile acids act as important signaling molecules that regulate lipid,glucose and energy metabolism via activating nuclear receptor,G protein-coupled receptors(GPCRs),Takeda G protein receptor 5(TGR5)and sphingosine-1-phosphate receptor 2(S1PR2).Sphingosine-1-phosphate(S1P)is synthesized by two sphingosine kinase isoforms and is a potent signaling molecule that plays a critical role in various diseases such as fatty liver,in-flammatory bowel disease(IBD)and colorectal cancer.In this review,we will focus on recent findings related to the role of S1P-mediated signaling pathways in the gut-liver axis.
文摘Mangoes (Mangifera indica L.) are one of the most important tropical foods. The seed is one of the main by-products of mango processing. Therefore, it is important to find an economically viable use for this waste (e.g., as a food additive or supplement with high nutraceutical value). We investigated the anti-obesity effects of mango seed kernel extract with hot water (MSKE-W) in 3T3-L1 adipocytes and in a high fat diet (HFD)-induced obesity rat model. MSKE-W caused a significant decrease in the activity of glycerol 2-phosphate dehydrogenase in 3T3-L1 adipocytes without eliciting cell cytotoxicity and inhibited cellular lipid accumulation through down-regulation of transcription factors such as PPARγ and C/EBPα. In the animal model, rats fed an HFD containing 1% MSKE-W gained less weight than rats fed an HFD alone. The visceral fat mass in rats fed an HFD containing 1% MSKE-W tended to be lower than that in rats fed an HFD alone. Furthermore, histological examination of rat livers from an HFD showed steatohepatitis. However, rats on an HFD containning 1% MSKE-W showed no histopathological changes in liver tissue. Our results indicate that MSKE-W influences anti-obesity effects, both in vitro and in vivo, and suggest that MSKE-W provides a novel preventive potential against obesity.
基金partly supported by National Natural Science Foundation of China(82125026 and 82122009)Natural Science Foundation of Shandong Province(ZR2022QH241 and ZR2020ZD11,China)Seed Fund for Basic Research of University Research Committee of The University of Hong Kong(20161159263,Hong Kong,China)。
文摘The mechanisms underlying autophagic defects in nonalcoholic steatohepatitis(NASH)remain largely unknown.We aimed to elucidate the roles of hepatic cyclooxygenase 1(COX1)in autophagy and the pathogenesis of diet-induced steatohepatitis in mice.Human nonalcoholic fatty liver disease(NAFLD)liver samples were used to examine the protein expression of COX1 and the level of autophagy.Cox1^(Δhepa)mice and their wildtype littermates were generated and fed with 3 different NASH models.We found that hepatic COX1 expression was increased in patients with NASH and diet induced NASH mice models accompanied by impaired autophagy.COX1 was required for basal autophagy in hepatocytes and liver specific COX1 deletion exacerbated steatohepatitis by inhibiting autophagy.Mechanistically,COX1 directly interacted with WD repeat domain,phosphoinositide interacting 2(WIPI2),which was crucial for autophagosome maturation.Adeno-associated virus(AAV)-mediated rescue of WIPI2 reversed the impaired autophagic flux and improved NASH phenotypes in Cox1^(Δhepa)mice,indicating that COX1 deletion-mediated steatohepatitis was partially dependent on WIPI2-mediated autophagy.In conclusion,we demonstrated a novel role of COX1 in hepatic autophagy that protected against NASH by interacting with WIPI2.Targeting the COX1 WIPI2 axis may be a novel therapeutic strategy for NASH.
基金This work was supported by the US National Institutes of Health(grants R01DK57543 and R01DK104893).
文摘Bile acids(BA)are synthesized from cholesterol in the liver.They are essential for promotion of the absorption of lipids,cholesterol,and lipid-soluble vitamins from the intestines.BAs are hormones that regulate nutrient metabolism by activating nuclear receptors(farnesoid X receptor(FXR),pregnane X receptor,vitamin D)and G protein-coupled receptors(e.g.,TGR5,sphingosine-1-phosphate receptor 2(S1PR2))in the liver and intestines.In the liver,S1PR2 activation by conjugated BAs activates the extracellular signal-regulated kinase 1/2 and AKT signaling pathways,and nuclear sphingosine kinase 2.The latter produces sphingosine-1-phosphate(S1P),an inhibitor of histone deacetylases 1/2,which allows for the differential up-regulation of expression of genes involved in the metabolism of sterols and lipids.We discuss here the emerging concepts of the interactions of BAs,FXR,insulin,S1P signaling and nutrient metabolism.
基金the USA National Institutes of Health(NIH)R01CA222490.
文摘Over 20%of mortality during acute liver failure is associated with the development of hepatic encephalopathy(HE).Thus,HE is a complication of acute liver failure with a broad spectrum of neuropsychiatric abnormalities ranging from subclinical alterations to coma.HE is caused by the diversion of portal blood into systemic circulation through portosystemic collateral vessels.Thus,the brain is exposed to intestinal-derived toxic substances.Moreover,the strategies to prevent advancement and improve the prognosis of such a liver-brain disease rely on intestinal microbial modulation.This is supported by the findings that antibiotics such as rifaximin and laxative lactulose can alleviate hepatic cirrhosis and/or prevent HE.Together,the significance of the gut-liver-brain axis in human health warrants attention.This review paper focuses on the roles of bacteria metabolites,mainly ammonia and bile acids(BAs)as well as BA receptors in HE.The literature search conducted for this review included searches for phrases such as BA receptors,BAs,ammonia,farnesoid X receptor(FXR),G protein-coupled bile acid receptor 1(GPBAR1 or TGR5),sphingosine-1-phosphate receptor 2(S1PR2),and cirrhosis in conjunction with the phrase hepatic encephalopathy and portosystemic encephalopathy.PubMed,as well as Google Scholar,was the search engines used to find relevant publications.
