采用扫描电镜观察了不同碱度(0、2、4 g/L Na HCO_3)胁迫对尼罗罗非鱼(Oreochromis niloticus)鳃离子细胞形态变化的影响,并采用免疫组化技术观察了鳃、肾、肠中4个HCO_3^-转运因子碳酸酐酶(CAⅡ、CAⅣ)、碳酸氢钠协同转运载体(SLC4A4)...采用扫描电镜观察了不同碱度(0、2、4 g/L Na HCO_3)胁迫对尼罗罗非鱼(Oreochromis niloticus)鳃离子细胞形态变化的影响,并采用免疫组化技术观察了鳃、肾、肠中4个HCO_3^-转运因子碳酸酐酶(CAⅡ、CAⅣ)、碳酸氢钠协同转运载体(SLC4A4)、Cl^-/HCO_3^-离子交换体(SLC26A6)的阳性反应变化。扫描电镜结果表明,鳃离子细胞分布在鳃小片基部。根据其表面开孔形状和尺寸,可分为Ⅰ型、Ⅱ型、Ⅲ型和Ⅳ型4种亚型,各亚型离子细胞的开孔尺寸随碱度胁迫强度增高呈正比增大,Ⅲ型离子细胞开孔尺寸变化最明显(P<0.01);离子细胞总数目也随碱度升高而增加,Ⅲ型离子细胞数目上升最为显著(P<0.01)。免疫组化结果表明,在淡水、碱水组中,CAⅡ、CAⅣ、SLC4A4、SLC26A6在鳃小片基部和肾中均有阳性反应,且随着碱度升高,阳性反应增强,但在肠道中未观察到阳性反应。本研究结果初步表明,尼罗罗非鱼可通过鳃离子细胞形态和数量调节适应碱度变化,鳃和肾为主要应答调节器官。展开更多
AIM To investigate the hypothesis that cardiomyocytespecific loss of the electrogenic NBCe1 Na^+-HCO3^- cotransporter is cardioprotective during in vivo ischemiareperfusion(IR)injury.METHODS An NBCe1 (Slc4a4 gene) con...AIM To investigate the hypothesis that cardiomyocytespecific loss of the electrogenic NBCe1 Na^+-HCO3^- cotransporter is cardioprotective during in vivo ischemiareperfusion(IR)injury.METHODS An NBCe1 (Slc4a4 gene) conditional knockout mouse(KO)model was prepared by gene targeting.Cardiovascular performance of wildtype (WT) and cardiac-specific NBCe1 KO mice was analyzed by intraventricular pressure measurements,and changes in cardiac gene expression were determined by RNA Seq analysis.Response to in vivo IR injury was analyzed after 30 min occlusion of the left anterior descending artery followed by 3 h of reperfusion. RESULTS Loss of NBCe1 in cardiac myocytes did not impair cardiac contractility or relaxation under basal conditions or in response toβ-adrenergic stimulation,and caused only limited changes in gene expression patterns,such as those for electrical excitability.However,following ischemia and reperfusion,KO heart sections exhibited significantly fewer apoptotic nuclei than WT sections.CONCLUSION These studies indicate that cardiac-specific loss of NBCe1 does not impair cardiovascular performance,causes only minimal changes in gene expression patterns,and protects against IR injury in vivo.展开更多
Nicotinamide adenine dinucleotide(NAD)is well known as a coenzyme involved in many redox reactions in cellular energy metabolism,or as a substrate for many NAD+-consuming enzymes,including those that generate the seco...Nicotinamide adenine dinucleotide(NAD)is well known as a coenzyme involved in many redox reactions in cellular energy metabolism,or as a substrate for many NAD+-consuming enzymes,including those that generate the second messenger cyclic ADP-ribose or deacetylate proteins(e.g.,histones).The role of NAD in non-catalytic proteins is poorly understood.IRBIT and L-IRBIT(the IRBITs)are two cytosolic proteins that are structurally related to dehydrogenases but lack catalytic activity.Instead,by interacting directly with their targets,the IRBITs modulate the function of numerous proteins with important roles,ranging from Ca2+signaling and intracellular pH(pHi)regulation to DNA metabolism to autophagy.Among the targets of the IRBITs is the Na+-HCO3−cotransporter NBCe1-B,which plays a central role in intracellular pH(pHi)regulation and epithelial electrolyte transport.Here,we demonstrate that NAD modulates NBCe1-B activation by serving as a cofactor of IRBIT or L-IRBIT.Blocking NAD salvage pathway greatly decreases NBCe1-B activation by the IRBITs.Administration of the oxidized form NAD+enhances,whereas the reduced form NADH decreases NBCe1-B activity.Our study represents the first example in which the redox state of NAD,via IRBIT or L-IRBIT,modulates the function of a membrane transport protein.Our findings reveal a new role of NAD and greatly expand our understanding of NAD biology.Because the NAD redox state fluctuates greatly with metabolic status,our work provides insight into how,via the IRBITs,energy metabolism could affect pHi regulation and many other IRBIT-dependent processes.展开更多
文摘采用扫描电镜观察了不同碱度(0、2、4 g/L Na HCO_3)胁迫对尼罗罗非鱼(Oreochromis niloticus)鳃离子细胞形态变化的影响,并采用免疫组化技术观察了鳃、肾、肠中4个HCO_3^-转运因子碳酸酐酶(CAⅡ、CAⅣ)、碳酸氢钠协同转运载体(SLC4A4)、Cl^-/HCO_3^-离子交换体(SLC26A6)的阳性反应变化。扫描电镜结果表明,鳃离子细胞分布在鳃小片基部。根据其表面开孔形状和尺寸,可分为Ⅰ型、Ⅱ型、Ⅲ型和Ⅳ型4种亚型,各亚型离子细胞的开孔尺寸随碱度胁迫强度增高呈正比增大,Ⅲ型离子细胞开孔尺寸变化最明显(P<0.01);离子细胞总数目也随碱度升高而增加,Ⅲ型离子细胞数目上升最为显著(P<0.01)。免疫组化结果表明,在淡水、碱水组中,CAⅡ、CAⅣ、SLC4A4、SLC26A6在鳃小片基部和肾中均有阳性反应,且随着碱度升高,阳性反应增强,但在肠道中未观察到阳性反应。本研究结果初步表明,尼罗罗非鱼可通过鳃离子细胞形态和数量调节适应碱度变化,鳃和肾为主要应答调节器官。
基金supported by the National Natural Science Foundation of China (No.3100051730900513)+2 种基金the Fundamental Research Funds for the Central UniversitiesMinistry of EducationChina (No.HUST: 2011TS099)
基金Supported by NIH grants,No.HL061974(to Gary E Shull),No.R01HL136025(to Yigang Wang),No.P30ES006096(to Mario Medvedovic)funds from the Center for Clinical and Translational Science and Training,University of Cincinnati(to Gary E Shull)a Research Innovation Seed Grant from the University of Cincinnati(to Gary E Shull and John N Lorenz)
文摘AIM To investigate the hypothesis that cardiomyocytespecific loss of the electrogenic NBCe1 Na^+-HCO3^- cotransporter is cardioprotective during in vivo ischemiareperfusion(IR)injury.METHODS An NBCe1 (Slc4a4 gene) conditional knockout mouse(KO)model was prepared by gene targeting.Cardiovascular performance of wildtype (WT) and cardiac-specific NBCe1 KO mice was analyzed by intraventricular pressure measurements,and changes in cardiac gene expression were determined by RNA Seq analysis.Response to in vivo IR injury was analyzed after 30 min occlusion of the left anterior descending artery followed by 3 h of reperfusion. RESULTS Loss of NBCe1 in cardiac myocytes did not impair cardiac contractility or relaxation under basal conditions or in response toβ-adrenergic stimulation,and caused only limited changes in gene expression patterns,such as those for electrical excitability.However,following ischemia and reperfusion,KO heart sections exhibited significantly fewer apoptotic nuclei than WT sections.CONCLUSION These studies indicate that cardiac-specific loss of NBCe1 does not impair cardiovascular performance,causes only minimal changes in gene expression patterns,and protects against IR injury in vivo.
基金supported by the National Natural Science Foundation of China(32271195)Shenzhen Science and Technology Program(JCYJ20220530161011025 and GJHZ20240218114705011)the National Institutes of Health,USA(R01-DK128315 to Walter F.Boron).
文摘Nicotinamide adenine dinucleotide(NAD)is well known as a coenzyme involved in many redox reactions in cellular energy metabolism,or as a substrate for many NAD+-consuming enzymes,including those that generate the second messenger cyclic ADP-ribose or deacetylate proteins(e.g.,histones).The role of NAD in non-catalytic proteins is poorly understood.IRBIT and L-IRBIT(the IRBITs)are two cytosolic proteins that are structurally related to dehydrogenases but lack catalytic activity.Instead,by interacting directly with their targets,the IRBITs modulate the function of numerous proteins with important roles,ranging from Ca2+signaling and intracellular pH(pHi)regulation to DNA metabolism to autophagy.Among the targets of the IRBITs is the Na+-HCO3−cotransporter NBCe1-B,which plays a central role in intracellular pH(pHi)regulation and epithelial electrolyte transport.Here,we demonstrate that NAD modulates NBCe1-B activation by serving as a cofactor of IRBIT or L-IRBIT.Blocking NAD salvage pathway greatly decreases NBCe1-B activation by the IRBITs.Administration of the oxidized form NAD+enhances,whereas the reduced form NADH decreases NBCe1-B activity.Our study represents the first example in which the redox state of NAD,via IRBIT or L-IRBIT,modulates the function of a membrane transport protein.Our findings reveal a new role of NAD and greatly expand our understanding of NAD biology.Because the NAD redox state fluctuates greatly with metabolic status,our work provides insight into how,via the IRBITs,energy metabolism could affect pHi regulation and many other IRBIT-dependent processes.
