Mistry S K, Chatterjee P K, Weerackody R P, Hawksworth G M, Knott R M, McLay J S
Department of Medicine, Aberdeen University Medical School, UK.
Exp Nephrol. 1998 Mar-Apr;6(2):104-11. doi: 10.1159/000020512.
Culture and natriuretic peptide dependent changes in the expression of the natriuretic peptides atrial natriuretic factor (ANF), brain natriuretic peptide (BNP), and C-type natriuretic peptide (CNP) and the natriuretic peptide receptors A, B, and C in primary cultures of rat proximal tubular cells were demonstrated using polymerase chain reaction analysis and cyclic guanosine monophosphate response to ANF and CNP. Freshly isolated cells expressed mRNA coding for the natriuretic peptide receptor C only, with no expression of the natriuretic peptides or the natriuretic peptide receptors A or B. At confluence natriuretic peptide receptor C expression was lost, while mRNA transcripts for both ANF and BNP and the A and B receptors became apparent. The appearance of mRNA transcripts for the natriuretic peptide receptors A and B during cell growth correspond with a significant increase in the cyclic guanosine monophosphate response to both ANF and CNP, confirming the presence of functionally active guanylate cyclase linked A and B natriuretic peptide receptors. The observed changes in peptide receptor expression during culture were preceded by changes in natriuretic peptide mRNA expression, suggesting the possibility that natriuretic peptide receptor subtype switching may be under the control of endogenous peptide release. Incubation of freshly isolated proximal tubular cells with ANF, BNP, or CNP for 3 h induced similar changes in receptor expression. Incubation with ANF induced expression of the natriuretic peptide receptor B and CNP while inhibiting natriuretic peptide receptor C. Incubation with BNP induced expression of the natriuretic peptide receptor B and CNP. Incubation with CNP induced expression of the natriuretic peptide receptors A and B and CNP. These results suggest that primary cultures of rat proximal tubular cells may experience natriuretic peptide and natriuretic peptide receptor subtype switching as they approach confluence under the control of endogenously expressed natriuretic peptides.
利用聚合酶链反应分析以及心房钠尿肽（ANF）和C型钠尿肽（CNP）的环磷酸鸟苷反应，证实了大鼠近端肾小管细胞原代培养物中，钠尿肽心房钠尿肽因子（ANF）、脑钠尿肽（BNP）和C型钠尿肽（CNP）以及钠尿肽受体A、B和C的表达受培养环境和钠尿肽的影响。刚分离出的细胞仅表达编码钠尿肽受体C的mRNA，而不表达钠尿肽或钠尿肽受体A或B。汇合时，钠尿肽受体C的表达消失，而ANF和BNP以及A和B受体的mRNA转录本变得明显。在细胞生长过程中，钠尿肽受体A和B的mRNA转录本的出现与对ANF和CNP的环磷酸鸟苷反应的显著增加相对应，证实了存在功能活跃的与鸟苷酸环化酶相连的A和B钠尿肽受体。在培养过程中观察到的肽受体表达变化之前，钠尿肽mRNA表达发生了变化，这表明钠尿肽受体亚型转换可能受内源性肽释放控制。将刚分离的近端肾小管细胞与ANF、BNP或CNP孵育3小时，可诱导受体表达发生类似变化。与ANF孵育可诱导钠尿肽受体B和CNP的表达，同时抑制钠尿肽受体C。与BNP孵育可诱导钠尿肽受体B和CNP的表达。与CNP孵育可诱导钠尿肽受体A、B和CNP的表达。这些结果表明，大鼠近端肾小管细胞原代培养物在接近汇合时，可能在内源性表达的钠尿肽控制下经历钠尿肽和钠尿肽受体亚型转换。
