Background:Atrial natriuretic peptide(ANP)and its natriuretic peptide receptors A(NPR-A)and C(NPR-C)are involved in the regulation of physiological and pathophysiological process of blood pressure.The present study ai...Background:Atrial natriuretic peptide(ANP)and its natriuretic peptide receptors A(NPR-A)and C(NPR-C)are involved in the regulation of physiological and pathophysiological process of blood pressure.The present study aimed to determine the role of NPR-C in the development of salt-sensitive hypertension.Methods::The Dahl salt-sensitive(DS)and salt-resistant(DR)rats were used in this study.Animals were matched according to their age and weight,and then placed on either a high-salt(HS,8%)or a normal-salt(NS,0.4%)diet for 6 weeks randomly using random number table.The systolic blood pressure(SBP),plasmatic sodium concentration(PL Na),urinary sodium excretion(UV Na),and serum creatinine concentration(Scr)were measured.The concentration of ANP in blood and tissues(heart and kidney)was detected by enzyme-linked immunosorbent assay.The expression of ANP,NPR-A,and NPR-C in kidney was evaluated with western blot analysis.Regarding renal redox state,the concentration changes in malondialdehyde(MDA),lipofuscin,nicotinamide adenine dinucleotide phosphate(NADPH)oxidase(Nox),and nitric oxide synthase(NOS)in kidney were detected by a spectrophotometric method.The kidney damage was evaluated using pathological techniques and the succinodehydrogenase(SDHase)examination.Furthermore,after an intra-peritoneal injection of C-atrial natriuretic peptide(ANP)4-23(C-ANP 4-23),an NPR-C receptor agonist,the SBP,biochemical values in blood and urine,and renal redox state were evaluated.The paired Student’s t test and analysis of variance followed by the Bonferroni test were performed for statistical analyses of the comparisons between two groups and multiple groups,respectively.Results::The baseline SBP in all groups was within the normal range.At the end of the 6-week experiment,HS diet significantly increased the SBP in DS rats from 116.63±2.90 mmHg to 162.25±2.15 mmHg(t=-10.213,P<0.001).The changes of SBP were not significant in DS rats on an NS diet and DR rats on an NS diet or on an HS diet(all P>0.05).The significant increase of PL Na,UV Na,and Scr related to an HS diet was found in both DS and DR rats(all P<0.05).However,significant changes in the concentration(t=-21.915,P<0.001)and expression of renal ANP(t=-3.566,P=0.016)and the expression of renal NPR-C(t=5.864,P=0.002)were only observed in DS hypertensive rats.The significantly higher desmin immunochemical staining score(t=-5.715,P=0.005)and mitochondrial injury score(t=-6.325,P=0.003)accompanied by the lower SDHase concentration(t=3.972,P=0.017)revealed mitochondrial pathologic abnormalities in podocytes in DS rats with an HS diet.The distinct increases of MDA(t=-4.685,P=0.009),lipofuscin(t=-8.195,P=0.001),and Nox(t=-12.733,P<0.001)but not NOS(t=-0.328,P=0.764)in kidneys were also found in DS hypertensive rats.C-ANP 4-23 treatment significantly decreased the SBP induced by HS in DS rats(P<0.05),which was still higher than NS groups with the vehicle or C-ANP 4-23 treatment(P<0.05).Moreover,the HS-induced increase of MDA,lipofuscin,Nox concentrations,and Nox4 expression in DS rats was significantly attenuated by C-ANP 4-23 treatment as compared with those with HS diet and vehicle injection(all P<0.05).Conclusions::The results indicated that the renal NPR-C might be involved in the salt-sensitive hypertension through the damage of mitochondria in podocytes and the reduction of the anti-oxidative function.Hence,C-ANP 4-23 might serve as a therapeutic agent in treating salt-sensitive hypertension.展开更多
基金This study was supported by grants from Natural Science Foundation of Shandong Province(Nos.BS2014YY004 and ZR2014HQ064)National Natural Science Foundation of China(No.81500413)Key Research and Development Program of Shandong Province(No.2017GSF218032).
文摘Background:Atrial natriuretic peptide(ANP)and its natriuretic peptide receptors A(NPR-A)and C(NPR-C)are involved in the regulation of physiological and pathophysiological process of blood pressure.The present study aimed to determine the role of NPR-C in the development of salt-sensitive hypertension.Methods::The Dahl salt-sensitive(DS)and salt-resistant(DR)rats were used in this study.Animals were matched according to their age and weight,and then placed on either a high-salt(HS,8%)or a normal-salt(NS,0.4%)diet for 6 weeks randomly using random number table.The systolic blood pressure(SBP),plasmatic sodium concentration(PL Na),urinary sodium excretion(UV Na),and serum creatinine concentration(Scr)were measured.The concentration of ANP in blood and tissues(heart and kidney)was detected by enzyme-linked immunosorbent assay.The expression of ANP,NPR-A,and NPR-C in kidney was evaluated with western blot analysis.Regarding renal redox state,the concentration changes in malondialdehyde(MDA),lipofuscin,nicotinamide adenine dinucleotide phosphate(NADPH)oxidase(Nox),and nitric oxide synthase(NOS)in kidney were detected by a spectrophotometric method.The kidney damage was evaluated using pathological techniques and the succinodehydrogenase(SDHase)examination.Furthermore,after an intra-peritoneal injection of C-atrial natriuretic peptide(ANP)4-23(C-ANP 4-23),an NPR-C receptor agonist,the SBP,biochemical values in blood and urine,and renal redox state were evaluated.The paired Student’s t test and analysis of variance followed by the Bonferroni test were performed for statistical analyses of the comparisons between two groups and multiple groups,respectively.Results::The baseline SBP in all groups was within the normal range.At the end of the 6-week experiment,HS diet significantly increased the SBP in DS rats from 116.63±2.90 mmHg to 162.25±2.15 mmHg(t=-10.213,P<0.001).The changes of SBP were not significant in DS rats on an NS diet and DR rats on an NS diet or on an HS diet(all P>0.05).The significant increase of PL Na,UV Na,and Scr related to an HS diet was found in both DS and DR rats(all P<0.05).However,significant changes in the concentration(t=-21.915,P<0.001)and expression of renal ANP(t=-3.566,P=0.016)and the expression of renal NPR-C(t=5.864,P=0.002)were only observed in DS hypertensive rats.The significantly higher desmin immunochemical staining score(t=-5.715,P=0.005)and mitochondrial injury score(t=-6.325,P=0.003)accompanied by the lower SDHase concentration(t=3.972,P=0.017)revealed mitochondrial pathologic abnormalities in podocytes in DS rats with an HS diet.The distinct increases of MDA(t=-4.685,P=0.009),lipofuscin(t=-8.195,P=0.001),and Nox(t=-12.733,P<0.001)but not NOS(t=-0.328,P=0.764)in kidneys were also found in DS hypertensive rats.C-ANP 4-23 treatment significantly decreased the SBP induced by HS in DS rats(P<0.05),which was still higher than NS groups with the vehicle or C-ANP 4-23 treatment(P<0.05).Moreover,the HS-induced increase of MDA,lipofuscin,Nox concentrations,and Nox4 expression in DS rats was significantly attenuated by C-ANP 4-23 treatment as compared with those with HS diet and vehicle injection(all P<0.05).Conclusions::The results indicated that the renal NPR-C might be involved in the salt-sensitive hypertension through the damage of mitochondria in podocytes and the reduction of the anti-oxidative function.Hence,C-ANP 4-23 might serve as a therapeutic agent in treating salt-sensitive hypertension.
文摘目的:分析趋化因子受体8(C⁃C motif chemokine receptor 8,CCR8)在卵巢癌肿瘤浸润性调节性T细胞(regulatory T cell,Treg)中的表达,探讨CCR8对Treg分化的作用。方法:构建C57BL/6小鼠卵巢癌细胞ID8荷瘤模型;流式细胞术检测小鼠肿瘤组织、脾脏和外周血中Treg上CCR8的表达比例,CCR8^(+)Treg上免疫检查点相关蛋白程序性细胞死亡蛋白1(programmed cell death protein 1,PD⁃1)、细胞素性T淋巴细胞抗原4(cytotoxic T⁃lymphocyte antigen 4,CTLA⁃4)、可诱导的T细胞共刺激分子(inducible T cell costimulators,ICOS)、淋巴细胞激活基因3(lymphocyte activation gene 3,LAG⁃3)的表达;流式细胞术检测CCR8变构抑制剂AZ084加入前后对C57BL/6小鼠脾脏中初始CD4^(+)T细胞向Treg分化的影响。结果:卵巢癌荷瘤小鼠肿瘤中Treg上的CCR8表达相比脾脏、外周血的Treg显著增高;相比CCR8^(-)Treg,CCR8^(+)Treg上免疫检查点相关蛋白表达更高;AZ084有效抑制小鼠脾脏中初始CD4^(+)T细胞向Treg的分化。结论:CCR8^(+)Treg在肿瘤浸润性Treg中占主要比例,CCR8作为卵巢癌浸润性Treg的主要标志物,变构CCR8蛋白可以抑制Treg的分化。靶向消除CCR8^(+)Treg可为改善卵巢癌肿瘤微环境的免疫抑制状态提供新思路。
