Background and aim:Glucocorticoids are the only first-line drugs for severe alcoholic hepatitis(AH),with limited efficacy and various side effects on extrahepatic tissues.Liver-targeting glucocorticoid therapy may hav...Background and aim:Glucocorticoids are the only first-line drugs for severe alcoholic hepatitis(AH),with limited efficacy and various side effects on extrahepatic tissues.Liver-targeting glucocorticoid therapy may have multiple advantages over systemic glucocorticoid for AH.The aim of this study was to determine the role of hepatocellular glucocorticoid receptor(GR)in alcohol-associated steatosis(AS)and AH.Materials and methods:AS was induced by a high-fat diet plus binge alcohol in adult male and female mice with liver-specific knockout(LKO)and heterozygote of GR.AH was induced by chronic-plus-binge in middle-aged male mice with liver-specific knockin of GR.Changes in hepatic mRNA and protein expression were determined by quantitative real-time polymerase chain reaction and Western blot.Results:GR-LKO aggravated steatosis and decreased hepatic expression and circulating levels of albumin in both genders of AS mice but only increased markers of liver injury in male AS mice.Marked steatosis in GR-LKO mice was associated with induction of lipogenic genes and down-regulation of bile acid synthetic genes.Hepatic protein levels of GR,hepatocyte nuclear factor 4 alpha,and phosphorylated signal transducer and activator of transcription 3 were gene-dosage-dependently decreased,whereas that of lipogenic ATP citrate lyase was increased in male GR heterozygote and LKO mice.Interestingly,hepatic expression of estrogen receptor alpha(ERα)was induced,and the essential estrogen-inactivating enzyme sulfotransferase 1e1 was gene-dosage-dependently down-regulated in GR heterozygote and knockout AS mice,which was associated with induction of ERα-target genes.Liver-specific knockin of GR protected against liver injury and steatohepatitis in middle-aged AH mice.Conclusions:Hepatic GR deficiency plays a crucial role in the pathogenesis of AS induced by high-fat diet plus binge,and liver-specific overexpression/activation of GR protects against chronic-plus-binge-induced AH in middle-aged mice.Hepatocellular GR is important for protection against AS and AH.展开更多
The zebrafish has become a popular vertebrate animal model in biomedical research.However,it is still challenging to make conditional gene knockout(CKO)models in zebrafish due to the low efficiency of homologous recom...The zebrafish has become a popular vertebrate animal model in biomedical research.However,it is still challenging to make conditional gene knockout(CKO)models in zebrafish due to the low efficiency of homologous recombination(HR).Here we report an efficient non-HR-based method for generating zebrafish carrying a CKO and knockin(KI)switch(zCKOIS)coupled with dual-color fluorescent reporters.Using this strategy,we generated hey2^zCKOIS which served as a hey2 KI reporter with EGFP expression.Upon Cre induction in targeted cells,the hey2^zCKOIS was switched to a non-functional CKO allele hey2^zCKOIS-inv associated with Tag RFP expression,enabling visualization of the CKO alleles.Thus,simplification of the design,and the visibility and combination of both CKO and KI alleles make our z CKOIS strategy an applicable CKO approach for zebrafish.展开更多
Background:The GGGGCC(G4C2)repeat expansion in the human open reading frame 72 on chromosome 9,C9orf72,is the most common cause of amyotrophic lateral sclerosis(ALS).Studies in transgenic mouse models have linked the ...Background:The GGGGCC(G4C2)repeat expansion in the human open reading frame 72 on chromosome 9,C9orf72,is the most common cause of amyotrophic lateral sclerosis(ALS).Studies in transgenic mouse models have linked the pathogenic mechanism of G4C2 repeat expansion to RNA foci or the accumulation of unnatural dipeptide repeats in neurons.However,only one of the existing transgenic mouse lines developed typical ALS.Methods:C9orf72 knockin rats were generated by knockin of 80 G4C2 repeats with human flanking fragments within exon1a and exon1b at the rat C9orf72 locus.Protein expression was detected by western blot.Motor coordination and grip force were measured using a Rotarod test and a grip strength test.Neurodegeneration was assessed by Nissl staining with cresyl violet.Results:C9orf72 haploinsufficiency reduced C9orf72 protein expression 40%in the cerebrum,cerebellum and spinal cords from knockin rats(P<.05).The knockin(KI)rats developed motor deficits from 4 months of age.Their falling latencies and grip force were decreased by 67%(P<.01)and 44%(P<.01),respectively,at 12 months of age compared to wild-type(WT)mice.The knockin of the hexanucleotide repeat expansion(HRE)caused a 47%loss of motor neurons in the spinal cord(P<.001)and 25%(5/20)of female KI rats developed hind limb paralysis at 13 to 24 months.Conclusion:Motor defects in KI rats may result from neurotoxicity caused by HRE and the resulting reduction in C9orf72 protein due to haploinsufficiency.These KI rats could be a useful model for investigating the contributions of loss-of-function to neurotoxicity in C9orf72-related ALS.展开更多
The electrogenic Na+-HCO3– cotransporter NBCe1 encoded by SLC4A4 gene plays essential roles in the regulation of intracellular/extracellular pH. Three NBCe1 variants are thought to mediate distinct physiological role...The electrogenic Na+-HCO3– cotransporter NBCe1 encoded by SLC4A4 gene plays essential roles in the regulation of intracellular/extracellular pH. Three NBCe1 variants are thought to mediate distinct physiological roles with different modes of transport stoichiometry. Homozygous inactivating mutations in NBCe1 cause the isolated proximal renal tubular acidosis (pRTA) invariably associated with ocular abnormalities. Functional analyses indicate that more than 50% reduction in NBCe1 activity may be required to induce severe acidemia. Some of the pRTA- related NBCe1 mutations, which show defective me-mbrane expression in mammalian cells, are also associated with migraine. Dysregulation of local pH in brain due to the loss of NBCe1 activity in astrocytes may underlie this association. Two types of NBCe1 deficient animals, NBCe1 knockout and W516X knockin mice, have been reported. Both of them show severe acidemia and early lethality unless they are treated with alkali. In isolated renal proximal tubules from W516X knockin mice, both NBCe1 activity and the rate of bicarbonate absorption are severely reduced, confirming the essential role of NBCe1 in bicarbonate absorption from this nephron segment. In this review, we summarize the recent data about physiological and pathophysiological roles of NBCe1 in health and diseases.展开更多
Mdm2 and Mdm4 are two key negative regulators of the tumor suppressor p53.Deletion of either Mdm2 or Mdm4 induces p53-dependent early embryonic lethality in knockout mouse models.The tissuespecific deletion of Mdm2 in...Mdm2 and Mdm4 are two key negative regulators of the tumor suppressor p53.Deletion of either Mdm2 or Mdm4 induces p53-dependent early embryonic lethality in knockout mouse models.The tissuespecific deletion of Mdm2 induces p53-dependent apoptosis,whereas the deletion of Mdm4 induces both p53-dependent apoptosis and cell cycle arrest.Compared to Mdm4 deletion,Mdm2 deletion causes more severe phenotypic defects.Disrupting the Mdm2 and Mdm4 interaction using knockin mice models causes embryonic lethality that can be completely rescued by the concomitant loss of p53,suggesting that Mdm2 and Mdm4 heterodimerization is critical to inhibit p53 activity during embryogenesis.Overexpression of Mdm2 and Mdm4 in mice induces spontaneous tumorigenesis,which clearly indicates that Mdm2 and Mdm4 are bona fide oncogenes.Studies from these mouse models strongly suggest that blocking Mdm2and Mdm4-mediated p53 inhibition is an appealing therapeutic strategy for cancer patients with wild-type p53 alleles.展开更多
基金supported by the National Institutes of Health(grant R21AA027349).
文摘Background and aim:Glucocorticoids are the only first-line drugs for severe alcoholic hepatitis(AH),with limited efficacy and various side effects on extrahepatic tissues.Liver-targeting glucocorticoid therapy may have multiple advantages over systemic glucocorticoid for AH.The aim of this study was to determine the role of hepatocellular glucocorticoid receptor(GR)in alcohol-associated steatosis(AS)and AH.Materials and methods:AS was induced by a high-fat diet plus binge alcohol in adult male and female mice with liver-specific knockout(LKO)and heterozygote of GR.AH was induced by chronic-plus-binge in middle-aged male mice with liver-specific knockin of GR.Changes in hepatic mRNA and protein expression were determined by quantitative real-time polymerase chain reaction and Western blot.Results:GR-LKO aggravated steatosis and decreased hepatic expression and circulating levels of albumin in both genders of AS mice but only increased markers of liver injury in male AS mice.Marked steatosis in GR-LKO mice was associated with induction of lipogenic genes and down-regulation of bile acid synthetic genes.Hepatic protein levels of GR,hepatocyte nuclear factor 4 alpha,and phosphorylated signal transducer and activator of transcription 3 were gene-dosage-dependently decreased,whereas that of lipogenic ATP citrate lyase was increased in male GR heterozygote and LKO mice.Interestingly,hepatic expression of estrogen receptor alpha(ERα)was induced,and the essential estrogen-inactivating enzyme sulfotransferase 1e1 was gene-dosage-dependently down-regulated in GR heterozygote and knockout AS mice,which was associated with induction of ERα-target genes.Liver-specific knockin of GR protected against liver injury and steatohepatitis in middle-aged AH mice.Conclusions:Hepatic GR deficiency plays a crucial role in the pathogenesis of AS induced by high-fat diet plus binge,and liver-specific overexpression/activation of GR protects against chronic-plus-binge-induced AH in middle-aged mice.Hepatocellular GR is important for protection against AS and AH.
基金supported by the Young Scientists Fund of the National Natural Science Foundation of China(31500849)Shanghai Municipal Science and Technology Major Project(18JC1410100,2018SHZDZX05)+3 种基金the Key Research Program of Frontier Sciences(QYZDY-SSW-SMC028)the Strategic Priority Research Program(XDB32010200)of Chinese Academy of Sciencesthe International Partnership Program,Bureau of International Co-operation of Chinese Academy of Sciences(153D31KYSB20170059)China Wan-Ren Program,and Shanghai Leading Scientist Program
文摘The zebrafish has become a popular vertebrate animal model in biomedical research.However,it is still challenging to make conditional gene knockout(CKO)models in zebrafish due to the low efficiency of homologous recombination(HR).Here we report an efficient non-HR-based method for generating zebrafish carrying a CKO and knockin(KI)switch(zCKOIS)coupled with dual-color fluorescent reporters.Using this strategy,we generated hey2^zCKOIS which served as a hey2 KI reporter with EGFP expression.Upon Cre induction in targeted cells,the hey2^zCKOIS was switched to a non-functional CKO allele hey2^zCKOIS-inv associated with Tag RFP expression,enabling visualization of the CKO alleles.Thus,simplification of the design,and the visibility and combination of both CKO and KI alleles make our z CKOIS strategy an applicable CKO approach for zebrafish.
基金National Natural Science Foundation of China(81571222),CAMS Innovation Fund for Medical Sciences(CIFMS,2016-I2M-1-004)Beijing Municipal Natural Science Foundation(7172135)。
文摘Background:The GGGGCC(G4C2)repeat expansion in the human open reading frame 72 on chromosome 9,C9orf72,is the most common cause of amyotrophic lateral sclerosis(ALS).Studies in transgenic mouse models have linked the pathogenic mechanism of G4C2 repeat expansion to RNA foci or the accumulation of unnatural dipeptide repeats in neurons.However,only one of the existing transgenic mouse lines developed typical ALS.Methods:C9orf72 knockin rats were generated by knockin of 80 G4C2 repeats with human flanking fragments within exon1a and exon1b at the rat C9orf72 locus.Protein expression was detected by western blot.Motor coordination and grip force were measured using a Rotarod test and a grip strength test.Neurodegeneration was assessed by Nissl staining with cresyl violet.Results:C9orf72 haploinsufficiency reduced C9orf72 protein expression 40%in the cerebrum,cerebellum and spinal cords from knockin rats(P<.05).The knockin(KI)rats developed motor deficits from 4 months of age.Their falling latencies and grip force were decreased by 67%(P<.01)and 44%(P<.01),respectively,at 12 months of age compared to wild-type(WT)mice.The knockin of the hexanucleotide repeat expansion(HRE)caused a 47%loss of motor neurons in the spinal cord(P<.001)and 25%(5/20)of female KI rats developed hind limb paralysis at 13 to 24 months.Conclusion:Motor defects in KI rats may result from neurotoxicity caused by HRE and the resulting reduction in C9orf72 protein due to haploinsufficiency.These KI rats could be a useful model for investigating the contributions of loss-of-function to neurotoxicity in C9orf72-related ALS.
文摘The electrogenic Na+-HCO3– cotransporter NBCe1 encoded by SLC4A4 gene plays essential roles in the regulation of intracellular/extracellular pH. Three NBCe1 variants are thought to mediate distinct physiological roles with different modes of transport stoichiometry. Homozygous inactivating mutations in NBCe1 cause the isolated proximal renal tubular acidosis (pRTA) invariably associated with ocular abnormalities. Functional analyses indicate that more than 50% reduction in NBCe1 activity may be required to induce severe acidemia. Some of the pRTA- related NBCe1 mutations, which show defective me-mbrane expression in mammalian cells, are also associated with migraine. Dysregulation of local pH in brain due to the loss of NBCe1 activity in astrocytes may underlie this association. Two types of NBCe1 deficient animals, NBCe1 knockout and W516X knockin mice, have been reported. Both of them show severe acidemia and early lethality unless they are treated with alkali. In isolated renal proximal tubules from W516X knockin mice, both NBCe1 activity and the rate of bicarbonate absorption are severely reduced, confirming the essential role of NBCe1 in bicarbonate absorption from this nephron segment. In this review, we summarize the recent data about physiological and pathophysiological roles of NBCe1 in health and diseases.
文摘Mdm2 and Mdm4 are two key negative regulators of the tumor suppressor p53.Deletion of either Mdm2 or Mdm4 induces p53-dependent early embryonic lethality in knockout mouse models.The tissuespecific deletion of Mdm2 induces p53-dependent apoptosis,whereas the deletion of Mdm4 induces both p53-dependent apoptosis and cell cycle arrest.Compared to Mdm4 deletion,Mdm2 deletion causes more severe phenotypic defects.Disrupting the Mdm2 and Mdm4 interaction using knockin mice models causes embryonic lethality that can be completely rescued by the concomitant loss of p53,suggesting that Mdm2 and Mdm4 heterodimerization is critical to inhibit p53 activity during embryogenesis.Overexpression of Mdm2 and Mdm4 in mice induces spontaneous tumorigenesis,which clearly indicates that Mdm2 and Mdm4 are bona fide oncogenes.Studies from these mouse models strongly suggest that blocking Mdm2and Mdm4-mediated p53 inhibition is an appealing therapeutic strategy for cancer patients with wild-type p53 alleles.
