目的研究B型利钠肽(BNP)对醛固酮(Ald)诱导的肾小管上皮细胞(RTEC)中利钠肽受体A(NPR-A)表达的影响,探寻肾脏发生BNP抵抗的机制。方法将正常状态的RTEC按BNP刺激浓度依次分为10-7 M BNP组、10-6 M BNP组和10-5 M BNP组;将Ald诱导的RTEC...目的研究B型利钠肽(BNP)对醛固酮(Ald)诱导的肾小管上皮细胞(RTEC)中利钠肽受体A(NPR-A)表达的影响,探寻肾脏发生BNP抵抗的机制。方法将正常状态的RTEC按BNP刺激浓度依次分为10-7 M BNP组、10-6 M BNP组和10-5 M BNP组;将Ald诱导的RTEC按BNP刺激浓度依次分为Ald+10-7 M BNP组、Ald+10-6 M BNP组和Ald+10-5 M BNP组。通过实时定量聚合酶链反应检测RTEC上NPR-A的转录水平,蛋白质印迹法、免疫荧光染色技术及质膜蛋白分离技术检测NPR-A的蛋白表达水平,酶联免疫吸附法检测环磷酸鸟苷(cGMP)含量。结果在正常RTEC中,随着BNP刺激浓度的升高,NPR-A的mRNA含量、蛋白表达量及cGMP含量均呈先增加后减少的趋势,高浓度BNP会抑制NPR-A的基因转录和蛋白表达,降低cGMP含量。在Ald诱导的RTEC中,随着BNP刺激浓度的升高,NPR-A的mRNA含量、蛋白表达量及cGMP含量均在轻微增加后急剧减少,高浓度BNP会明显抑制NPR-A的基因转录和蛋白表达,减少cGMP生成。当受到相同浓度BNP刺激时,Ald诱导的RTEC上NPR-A的转录水平及cGMP生成量均低于相应的正常RTEC。结论在正常/Ald诱导的RTEC中,胞膜和胞质上NPR-A的蛋白表达水平的变化趋势与总蛋白水平相一致,即呈先升后降的动态变化特点,高浓度BNP会下调NPR-A水平,减少cGMP生成。心力衰竭时发生的BNP抵抗现象与肾脏NPR-A的变化密切相关,RTEC纤维化可能是BNP抵抗的机制之一。展开更多
AIM: To study the sensitivity of gastric smooth muscle to C-type natriuretic peptide (CNP) in streptozotocin (STZ)-induced diabetic rats. METHODS: The spontaneous contraction of a gastric smooth muscle strip was recor...AIM: To study the sensitivity of gastric smooth muscle to C-type natriuretic peptide (CNP) in streptozotocin (STZ)-induced diabetic rats. METHODS: The spontaneous contraction of a gastric smooth muscle strip was recorded by using physiological methods in rats. The expressions of CNP and natriuretic peptide receptor-B (NPR-B) in gastric tissue were examined by using immunohistochemistry techniques in the diabetic rat. RESULTS: At 4 wk after injection of STZ and vehicle, the frequency of spontaneous contraction of gastric smooth muscle was significantly reduced in diabetic rats, and the frequency was decreased from 3.10 ± 0.14 cycle/min in controls to 2.23 ± 0.13 cycle/min (n = 8, P < 0.01). However, the amplitude of spontaneous contraction was not significant different from the normal rat. CNP significantly inhibited spontaneous contraction of gastric smooth muscle in normal and diabetic rats, but the inhibitory effect was significantly potentiated in the diabetic rats. The amplitudes of spontaneous contraction were suppressed by 75.15% ± 0.71% and 58.92% ± 1.32% while the frequencies were decreased by 53.33% ± 2.03% and 26.95% ± 2.82% in diabetic and normal rats, respectively (n = 8, P < 0.01). The expression of CNP in gastric tissue was not changed in diabetic rats, however the expression of NPR-B was significantly increased in diabetic rats, and the staining indexes of NPR-B were 30.67 ± 1.59 and 17.63 ± 1.49 in diabetic and normal rat, respectively (n = 8, P < 0.01).CONCLUSION: The results suggest that CNP induced an inhibitory effect on spontaneous contraction of gastric smooth muscle, potentiated in diabetic rat via up-regulation of the natriuretic peptides-NPR-B-particulate guanylyl cyclase-cyclic GMP signal pathway.展开更多
C-type natriuretic peptide (CNP) is a 22-amino acid peptide and act as a local paracrine or autocrine regulator. There is growing evidence that ChIP is involved in male reproductive processes. To investigate the rol...C-type natriuretic peptide (CNP) is a 22-amino acid peptide and act as a local paracrine or autocrine regulator. There is growing evidence that ChIP is involved in male reproductive processes. To investigate the role of CNPduring spermatogenesis, we measured the mRNA expression of CNPand its specific membrane-bound natriuretic peptide receptor-B (NPR-B) using real-time RT-PCR in the testes of normal rats on different postnatal days. After that spermatogenesis dysfunction model induced by ornidazole was established with the aim to study the correlation of CNPwith spermatogenic dysfunction. Then, Sertoli cells from 18- to 22-day-old healthy male rats were cultured in the presence of different CNPconcentrations (1 ×10-6, 1×10-7 and1×10-8 mol l-1), and the mRNA expression levels of androgen.binding protein, inhibin B and transferrin were examined at 0 min, 30 min, 1 h, 2 h, 4 h, 8 h, 12 h, 24 h and 48 h. During the postnatal development of rat testes, the highest mRNA expression levels of CNPand NPR-B were found at postnatal Do, and the levels then declined gradually, with a second ChIPpeak at postnatal D35. In the ornidazole-induced infertile rat testes, CIVPgene expression was lower than in the uninduced rats (P〈0.05), while IVPR-Bgene expression was greater (P〈0.05). In cultured Sertoli cells, supplementation with CNP stimulated the gene expression of androgen-binding pmteirginhibin B/transferrin, particularly at 12 h, and 1× 10-7 mol l-1 CNP had the highest upregulation effect. The gene expression levels of CNPIIVPR-B in rat testes at different postnatal stages and in infertile rat testes indicated that CNP may participate in the physiology and/or pathology related to spermatogenesis. Moreover, ChIP regulated endocrine function in Sertoli cells. Taken together, these results showed that CNP is closely tied to spermatogenesis.展开更多
The present study investigated a possible mechanism for endogenous endothelin-1 (ET-1) regulation of atrial natriuretic peptide (ANP) secretion in isolated perfused acute hypoxic rabbit atria. Acute hypoxia significan...The present study investigated a possible mechanism for endogenous endothelin-1 (ET-1) regulation of atrial natriuretic peptide (ANP) secretion in isolated perfused acute hypoxic rabbit atria. Acute hypoxia significantly enhanced the release of ET-1 and the expression of the ET receptor (ETR) type A and B (ETR<sub>A</sub> and ETR<sub>B</sub>) in atrial tissues, with a concomitant increase in ANP secretion. The ETR<sub>A</sub> or ETR<sub>B</sub> antagonist, BQ123 (0.3 μmol/L) or BQ788 (0.3 μmol/L), respectively attenuated hypoxia-induced ANP secretion. Both antagonists significantly attenuated the levels of hypoxiainduced atrial phosphorylated (p)-extracellular signal-regulated kinase (ERK) and p-protein kinase B (Akt). The ERK and Akt inhibitors, PD098059 (30 μmol/L) and LY294002 (30 μmol/L), respectively mimicked the effect of the ETR antagonists. These results demonstrated that acute hypoxia- mediated atrial ET-1 regulated ANP secretion through ETR and the subsequent mitogenactivated protein kinase (MAPK)/ERK and ETR-phosphatidylinositol-3-kinase (PI3K)/Akt signaling pathways. These pathways may mediate atrial endocrine functions under hypoxic conditions.展开更多
Heart failure(HF)is a clinical syndrome that results from a structural or functional cardiac disorder that reduces the ability of the ventricle of the heart to fill with,or eject,blood.It is a multifaceted clinical co...Heart failure(HF)is a clinical syndrome that results from a structural or functional cardiac disorder that reduces the ability of the ventricle of the heart to fill with,or eject,blood.It is a multifaceted clinical condition that affects up to 2%of the population in the developed world,and is linked to significant morbidity and mortality;it is therefore considered a major concern for public health.Regarding the mechanism of HF,three neurohumoral factors-the reninangiotensin-aldosterone system,the sympathetic nervous system,and natriuretic peptides—are related to the pathology of chronic HF(CHF),and the targets of treatment.Angiotensin receptor blocker and neprilysin inhibitor(angiotensinreceptor neprilysin inhibitor),namely sacubitril/valsartan(SAC/VAL),has been introduced as a treatment for CHF.SAC/VAL is an efficacious,safe,and costeffective therapy that improves quality of life and longevity in patients with HF with reduced ejection fraction(HFrEF),and reduces hospital admissions.An inhospital initiation strategy offers a potential new avenue to improve the clinical uptake of SAC/VAL.In the last five years,SAC/VAL has been established as a cornerstone component of comprehensive disease-modifying medical therapy in the management of chronic HFrEF.On the other hand,further work,with carefully designed and controlled preclinical studies,is necessary for understanding the molecular mechanisms,effects,and confirmation of issues such as long-term safety in both human and animal models.展开更多
文摘目的研究B型利钠肽(BNP)对醛固酮(Ald)诱导的肾小管上皮细胞(RTEC)中利钠肽受体A(NPR-A)表达的影响,探寻肾脏发生BNP抵抗的机制。方法将正常状态的RTEC按BNP刺激浓度依次分为10-7 M BNP组、10-6 M BNP组和10-5 M BNP组;将Ald诱导的RTEC按BNP刺激浓度依次分为Ald+10-7 M BNP组、Ald+10-6 M BNP组和Ald+10-5 M BNP组。通过实时定量聚合酶链反应检测RTEC上NPR-A的转录水平,蛋白质印迹法、免疫荧光染色技术及质膜蛋白分离技术检测NPR-A的蛋白表达水平,酶联免疫吸附法检测环磷酸鸟苷(cGMP)含量。结果在正常RTEC中,随着BNP刺激浓度的升高,NPR-A的mRNA含量、蛋白表达量及cGMP含量均呈先增加后减少的趋势,高浓度BNP会抑制NPR-A的基因转录和蛋白表达,降低cGMP含量。在Ald诱导的RTEC中,随着BNP刺激浓度的升高,NPR-A的mRNA含量、蛋白表达量及cGMP含量均在轻微增加后急剧减少,高浓度BNP会明显抑制NPR-A的基因转录和蛋白表达,减少cGMP生成。当受到相同浓度BNP刺激时,Ald诱导的RTEC上NPR-A的转录水平及cGMP生成量均低于相应的正常RTEC。结论在正常/Ald诱导的RTEC中,胞膜和胞质上NPR-A的蛋白表达水平的变化趋势与总蛋白水平相一致,即呈先升后降的动态变化特点,高浓度BNP会下调NPR-A水平,减少cGMP生成。心力衰竭时发生的BNP抵抗现象与肾脏NPR-A的变化密切相关,RTEC纤维化可能是BNP抵抗的机制之一。
基金Supported by The National Natural Science Foundation of China, No. 30760068
文摘AIM: To study the sensitivity of gastric smooth muscle to C-type natriuretic peptide (CNP) in streptozotocin (STZ)-induced diabetic rats. METHODS: The spontaneous contraction of a gastric smooth muscle strip was recorded by using physiological methods in rats. The expressions of CNP and natriuretic peptide receptor-B (NPR-B) in gastric tissue were examined by using immunohistochemistry techniques in the diabetic rat. RESULTS: At 4 wk after injection of STZ and vehicle, the frequency of spontaneous contraction of gastric smooth muscle was significantly reduced in diabetic rats, and the frequency was decreased from 3.10 ± 0.14 cycle/min in controls to 2.23 ± 0.13 cycle/min (n = 8, P < 0.01). However, the amplitude of spontaneous contraction was not significant different from the normal rat. CNP significantly inhibited spontaneous contraction of gastric smooth muscle in normal and diabetic rats, but the inhibitory effect was significantly potentiated in the diabetic rats. The amplitudes of spontaneous contraction were suppressed by 75.15% ± 0.71% and 58.92% ± 1.32% while the frequencies were decreased by 53.33% ± 2.03% and 26.95% ± 2.82% in diabetic and normal rats, respectively (n = 8, P < 0.01). The expression of CNP in gastric tissue was not changed in diabetic rats, however the expression of NPR-B was significantly increased in diabetic rats, and the staining indexes of NPR-B were 30.67 ± 1.59 and 17.63 ± 1.49 in diabetic and normal rat, respectively (n = 8, P < 0.01).CONCLUSION: The results suggest that CNP induced an inhibitory effect on spontaneous contraction of gastric smooth muscle, potentiated in diabetic rat via up-regulation of the natriuretic peptides-NPR-B-particulate guanylyl cyclase-cyclic GMP signal pathway.
文摘C-type natriuretic peptide (CNP) is a 22-amino acid peptide and act as a local paracrine or autocrine regulator. There is growing evidence that ChIP is involved in male reproductive processes. To investigate the role of CNPduring spermatogenesis, we measured the mRNA expression of CNPand its specific membrane-bound natriuretic peptide receptor-B (NPR-B) using real-time RT-PCR in the testes of normal rats on different postnatal days. After that spermatogenesis dysfunction model induced by ornidazole was established with the aim to study the correlation of CNPwith spermatogenic dysfunction. Then, Sertoli cells from 18- to 22-day-old healthy male rats were cultured in the presence of different CNPconcentrations (1 ×10-6, 1×10-7 and1×10-8 mol l-1), and the mRNA expression levels of androgen.binding protein, inhibin B and transferrin were examined at 0 min, 30 min, 1 h, 2 h, 4 h, 8 h, 12 h, 24 h and 48 h. During the postnatal development of rat testes, the highest mRNA expression levels of CNPand NPR-B were found at postnatal Do, and the levels then declined gradually, with a second ChIPpeak at postnatal D35. In the ornidazole-induced infertile rat testes, CIVPgene expression was lower than in the uninduced rats (P〈0.05), while IVPR-Bgene expression was greater (P〈0.05). In cultured Sertoli cells, supplementation with CNP stimulated the gene expression of androgen-binding pmteirginhibin B/transferrin, particularly at 12 h, and 1× 10-7 mol l-1 CNP had the highest upregulation effect. The gene expression levels of CNPIIVPR-B in rat testes at different postnatal stages and in infertile rat testes indicated that CNP may participate in the physiology and/or pathology related to spermatogenesis. Moreover, ChIP regulated endocrine function in Sertoli cells. Taken together, these results showed that CNP is closely tied to spermatogenesis.
文摘The present study investigated a possible mechanism for endogenous endothelin-1 (ET-1) regulation of atrial natriuretic peptide (ANP) secretion in isolated perfused acute hypoxic rabbit atria. Acute hypoxia significantly enhanced the release of ET-1 and the expression of the ET receptor (ETR) type A and B (ETR<sub>A</sub> and ETR<sub>B</sub>) in atrial tissues, with a concomitant increase in ANP secretion. The ETR<sub>A</sub> or ETR<sub>B</sub> antagonist, BQ123 (0.3 μmol/L) or BQ788 (0.3 μmol/L), respectively attenuated hypoxia-induced ANP secretion. Both antagonists significantly attenuated the levels of hypoxiainduced atrial phosphorylated (p)-extracellular signal-regulated kinase (ERK) and p-protein kinase B (Akt). The ERK and Akt inhibitors, PD098059 (30 μmol/L) and LY294002 (30 μmol/L), respectively mimicked the effect of the ETR antagonists. These results demonstrated that acute hypoxia- mediated atrial ET-1 regulated ANP secretion through ETR and the subsequent mitogenactivated protein kinase (MAPK)/ERK and ETR-phosphatidylinositol-3-kinase (PI3K)/Akt signaling pathways. These pathways may mediate atrial endocrine functions under hypoxic conditions.
文摘Heart failure(HF)is a clinical syndrome that results from a structural or functional cardiac disorder that reduces the ability of the ventricle of the heart to fill with,or eject,blood.It is a multifaceted clinical condition that affects up to 2%of the population in the developed world,and is linked to significant morbidity and mortality;it is therefore considered a major concern for public health.Regarding the mechanism of HF,three neurohumoral factors-the reninangiotensin-aldosterone system,the sympathetic nervous system,and natriuretic peptides—are related to the pathology of chronic HF(CHF),and the targets of treatment.Angiotensin receptor blocker and neprilysin inhibitor(angiotensinreceptor neprilysin inhibitor),namely sacubitril/valsartan(SAC/VAL),has been introduced as a treatment for CHF.SAC/VAL is an efficacious,safe,and costeffective therapy that improves quality of life and longevity in patients with HF with reduced ejection fraction(HFrEF),and reduces hospital admissions.An inhospital initiation strategy offers a potential new avenue to improve the clinical uptake of SAC/VAL.In the last five years,SAC/VAL has been established as a cornerstone component of comprehensive disease-modifying medical therapy in the management of chronic HFrEF.On the other hand,further work,with carefully designed and controlled preclinical studies,is necessary for understanding the molecular mechanisms,effects,and confirmation of issues such as long-term safety in both human and animal models.