Classical inhibitors of PDE4 lack subtype selectivity due to exact amino acid sequence conservation of the catalytic site,and consequently,development of these drugs has stalled due to dose-limiting side effects of na...Classical inhibitors of PDE4 lack subtype selectivity due to exact amino acid sequence conservation of the catalytic site,and consequently,development of these drugs has stalled due to dose-limiting side effects of nausea and emesis.While use of subtype-selective inhibitors(i.e.,for PDE4A,B,or D)could overcome this issue,conservation of the catalytic region,to which classical inhibitors bind,limits this approach.The present study examined the effects of BPN14770,an allosteric inhibitor of PDE4D,which binds to a primate-specific,N-terminal region,conferring greater than 260-fold selectivity for PDE4D.BPN14770 was 100-fold more potent for improving memory and cognition in humanized PDE4D(hPDE4D)mice,which expressed the primate-specific binding sequence,compared to wild-type mice;meanwhile,it exhibited low potency in a mouse surrogate model for emesis.The behavioral and matching neurochemical data presented established a relationship between PDE4D target engagement and effects on cognition for BPN14770.Furthermore,BPN14770 reversed memory and cognitive deficits induced byβ-amyloid peptide 1-42(Aβ42)in Morris water maze,Y maze and novel object recognition tests in the humanized PDE4D mice.The morphological analyses suggested that the number of dendrites and the dendritic length in the CA1 of hippocampus were significantly increased after the Aβ42-treated hPDE4D mice were administered of BPN14770 for two weeks.The neurochemical and molecular biological assays suggested that neuroplasticity-related proteins and neurotrophic factor BDNF in the hippocampus of hPDE4D mice were significantly increased after the hPDE4D mice were treated with BPN14770.These findings suggest clinical potential for PDE4D selective inhibitors in disorders with cognitive deficits such as Alzheimer’s disease,which affects approximately 20 million people worldwide and nearly 5 million people in the United States.展开更多
OBJECTIVE To examine whether long-form phosphodiesterase-4(PDE4)knockdown by lentiviral RNA construct containing a speci fi c micro RNA/mi RNAmir hairpin structure reversed depression-like symptoms caused by chronic u...OBJECTIVE To examine whether long-form phosphodiesterase-4(PDE4)knockdown by lentiviral RNA construct containing a speci fi c micro RNA/mi RNAmir hairpin structure reversed depression-like symptoms caused by chronic unpredictable mild stress(CUMS)in mice.METHODS In this research,the study was performed on adult male C57 mice,weighing(25±5)g,kept in a controlled environment.CUMS animal model was used recapitulate a multiple of behavioral characteristics and biochemical states of depression in human.The forced swimming test(FST)and the tail suspension test(TST)were used to detectthe state of depression.Western blotting analysis was used to assess protein levels of c AMP response element binding protein(CREB,unphosphorylated and phosphorylated[p CREB])to explore the neurochemical mechanisms.RESULTS CUMS decreased c AMP levels(P<0.01)and produced depression-like symptoms in FST(P<0.01)and TST(P<0.01).Microinfusions of lentiviruses reversed CUMS-induced c AMP decline(P<0.05)and depression-like symptoms.Moreover,CUMS caused a significant reduction in protein kinase A and CREB phosphorylation,and brain-derived neurotrophic factor transcription,both of which were partially attenuated by lentivirus-mediated knockdown of PDE4D.Also,the phosphorylation of extracellular signal-regulated kinase 1/2 was reduced in CUMS-exposed mice,which was reversed by 4Dmi RNA treatment.Taken together,this study demonstrated that PDE4Dmi RNA improved the CUMS-induced depressionlike symptoms that might be related to the increase in hippocampal c AMP and p CREB expression.CONCLUSION Hence,PDE4D inhibitors can serve as potential antidepressants,and their antidepressant activity is partially mediated by the activation of c AMP signaling pathway in the hippocampus.In other words,long-form PDE4D knockdown may offer a promising treatment for major depression disorder.展开更多
Cardiac Troponin I(cTnI)is a subunit of the thin filament involved in regulation of heart contraction.Mutated cTnI accounts for most genetic mutations associated with restric-tive cardiomyopathy(RCM).We previously fou...Cardiac Troponin I(cTnI)is a subunit of the thin filament involved in regulation of heart contraction.Mutated cTnI accounts for most genetic mutations associated with restric-tive cardiomyopathy(RCM).We previously found phosphodiesterase 4D(PDE4D)decreased in RCM mice with cTnIR193H mutation and the mutant cTnI might be involved in PDE4D reduction.This study aims to elucidate a novel role of cTnIR193H mutant as a gene regulator.Overexpres-sion of cTnIR193H mutant in cardiomyocytes showed decrease in PDED4D protein expression,while the enrichment of histone deacetylase 1(HDAC1)was increased along with decreases in acetylated lysine 4(acH3K4)and 9(acH3K9)levels in the PDE4D promoter.HDAC1 overex-pression could also downregulate PDE4D via reducing acH3K4 and acH3K9 levels.Co-IP assays showed that cTnIR193H mutant owed increased binding ability to HDAC1 compared with wild type cTnI.EGCG as a HDAC1 inhibitor could diminish the strength of cTnIR193H-HDAC1 inter-actions and alleviate the reduction in PDE4D expression.Together,our data indicated that cTnIR193H mutant could repress PDE4D expression in cardiomyocytes through HDAC1 associ-ated histone deacetylation modification.Unlike the typical function of cTnI in cytoplasm,our study suggested a novel role of cTnI mutants in nuclei in regulating gene expression.展开更多
文摘Classical inhibitors of PDE4 lack subtype selectivity due to exact amino acid sequence conservation of the catalytic site,and consequently,development of these drugs has stalled due to dose-limiting side effects of nausea and emesis.While use of subtype-selective inhibitors(i.e.,for PDE4A,B,or D)could overcome this issue,conservation of the catalytic region,to which classical inhibitors bind,limits this approach.The present study examined the effects of BPN14770,an allosteric inhibitor of PDE4D,which binds to a primate-specific,N-terminal region,conferring greater than 260-fold selectivity for PDE4D.BPN14770 was 100-fold more potent for improving memory and cognition in humanized PDE4D(hPDE4D)mice,which expressed the primate-specific binding sequence,compared to wild-type mice;meanwhile,it exhibited low potency in a mouse surrogate model for emesis.The behavioral and matching neurochemical data presented established a relationship between PDE4D target engagement and effects on cognition for BPN14770.Furthermore,BPN14770 reversed memory and cognitive deficits induced byβ-amyloid peptide 1-42(Aβ42)in Morris water maze,Y maze and novel object recognition tests in the humanized PDE4D mice.The morphological analyses suggested that the number of dendrites and the dendritic length in the CA1 of hippocampus were significantly increased after the Aβ42-treated hPDE4D mice were administered of BPN14770 for two weeks.The neurochemical and molecular biological assays suggested that neuroplasticity-related proteins and neurotrophic factor BDNF in the hippocampus of hPDE4D mice were significantly increased after the hPDE4D mice were treated with BPN14770.These findings suggest clinical potential for PDE4D selective inhibitors in disorders with cognitive deficits such as Alzheimer’s disease,which affects approximately 20 million people worldwide and nearly 5 million people in the United States.
基金The project supported by National Natural Science Foundation of China(81301099,81373384)Natural Science Foundation of Guangdong Province(S2013040014202)+1 种基金China Postdoctoral Science Foundation(2013M542192)National Science and Technology Major Projects for"Major New Drugs Innovation and Development"(2012ZX09J1211003C)
文摘OBJECTIVE To examine whether long-form phosphodiesterase-4(PDE4)knockdown by lentiviral RNA construct containing a speci fi c micro RNA/mi RNAmir hairpin structure reversed depression-like symptoms caused by chronic unpredictable mild stress(CUMS)in mice.METHODS In this research,the study was performed on adult male C57 mice,weighing(25±5)g,kept in a controlled environment.CUMS animal model was used recapitulate a multiple of behavioral characteristics and biochemical states of depression in human.The forced swimming test(FST)and the tail suspension test(TST)were used to detectthe state of depression.Western blotting analysis was used to assess protein levels of c AMP response element binding protein(CREB,unphosphorylated and phosphorylated[p CREB])to explore the neurochemical mechanisms.RESULTS CUMS decreased c AMP levels(P<0.01)and produced depression-like symptoms in FST(P<0.01)and TST(P<0.01).Microinfusions of lentiviruses reversed CUMS-induced c AMP decline(P<0.05)and depression-like symptoms.Moreover,CUMS caused a significant reduction in protein kinase A and CREB phosphorylation,and brain-derived neurotrophic factor transcription,both of which were partially attenuated by lentivirus-mediated knockdown of PDE4D.Also,the phosphorylation of extracellular signal-regulated kinase 1/2 was reduced in CUMS-exposed mice,which was reversed by 4Dmi RNA treatment.Taken together,this study demonstrated that PDE4Dmi RNA improved the CUMS-induced depressionlike symptoms that might be related to the increase in hippocampal c AMP and p CREB expression.CONCLUSION Hence,PDE4D inhibitors can serve as potential antidepressants,and their antidepressant activity is partially mediated by the activation of c AMP signaling pathway in the hippocampus.In other words,long-form PDE4D knockdown may offer a promising treatment for major depression disorder.
基金This study was supported by research grants from National Natural Science Foundation of China[grant number 81700214].
文摘Cardiac Troponin I(cTnI)is a subunit of the thin filament involved in regulation of heart contraction.Mutated cTnI accounts for most genetic mutations associated with restric-tive cardiomyopathy(RCM).We previously found phosphodiesterase 4D(PDE4D)decreased in RCM mice with cTnIR193H mutation and the mutant cTnI might be involved in PDE4D reduction.This study aims to elucidate a novel role of cTnIR193H mutant as a gene regulator.Overexpres-sion of cTnIR193H mutant in cardiomyocytes showed decrease in PDED4D protein expression,while the enrichment of histone deacetylase 1(HDAC1)was increased along with decreases in acetylated lysine 4(acH3K4)and 9(acH3K9)levels in the PDE4D promoter.HDAC1 overex-pression could also downregulate PDE4D via reducing acH3K4 and acH3K9 levels.Co-IP assays showed that cTnIR193H mutant owed increased binding ability to HDAC1 compared with wild type cTnI.EGCG as a HDAC1 inhibitor could diminish the strength of cTnIR193H-HDAC1 inter-actions and alleviate the reduction in PDE4D expression.Together,our data indicated that cTnIR193H mutant could repress PDE4D expression in cardiomyocytes through HDAC1 associ-ated histone deacetylation modification.Unlike the typical function of cTnI in cytoplasm,our study suggested a novel role of cTnI mutants in nuclei in regulating gene expression.
