Yamaguchi T, Pelling J C, Ramaswamy N T, Eppler J W, Wallace D P, Nagao S, Rome L A, Sullivan L P, Grantham J J
Department of Medicine, Kansas University Medical Center, Kansas City, Kansas, USA.
Kidney Int. 2000 Apr;57(4):1460-71. doi: 10.1046/j.1523-1755.2000.00991.x.
: Cellular proliferation is a key factor in the enlargement of renal cysts in autosomal dominant polycystic kidney disease (ADPKD). We determined the extent to which adenosine 3':5'-cyclic monophosphate (cAMP) may regulate the in vitro proliferation of cyst epithelial cells derived from human ADPKD cysts.
: Epithelial cells from cysts of individuals with ADPKD and from normal human kidney cortex (HKC) of individuals without ADPKD were cultured. The effects of agonists and inhibitors on the rate of cellular proliferation and the activation of extracellular signal-regulated kinase (ERK1/2) were determined.
: 8-Br-cAMP (100 micromol/L) stimulated the proliferation of cells from eight different ADPKD subjects to 99.0% above baseline; proliferation was inhibited by protein kinase A (PKA) antagonists H-89 (97%) and Rp-cAMP (90%). Forskolin (10 micromol/L), which activates adenylyl cyclase, increased proliferation 124%, and receptor-mediated agonists arginine vasopressin, desmopressin, secretin, vasoactive intestinal polypeptide, and prostaglandin E2 stimulated proliferation 54.2, 56.3, 46.7, 37.1, and 48.3%, respectively. The mitogen extracellular kinase (MEK) inhibitor PD98059 completely inhibited ADPKD cell proliferation in response to cAMP agonists, but genistein, a receptor tyrosine kinase inhibitor, did not block cAMP-dependent proliferation. cAMP agonists increased the activity of ERK above control levels within five minutes. In contrast to ADPKD, proliferation and ERK activity of cells derived from normal HKC were not stimulated by cAMP agonists, although electrogenic Cl- secretion was increased by these agonists in both ADPKD and HKC cell monolayers.
: We conclude that cAMP agonists stimulate the proliferation of ADPKD but not HKC epithelial cells through PKA activation of the ERK pathway at a locus distal to receptor tyrosine kinase. We suggest that the adenylyl cyclase signaling pathway may have a unique role in determining the rate of cyst enlargement in ADPKD through its actions to stimulate cellular proliferation and transepithelial solute and fluid secretion.
细胞增殖是常染色体显性多囊肾病（ADPKD）中肾囊肿增大的关键因素。我们确定了3':5'-环磷酸腺苷（cAMP）在体外调节源自人类ADPKD囊肿的囊肿上皮细胞增殖的程度。
培养来自ADPKD个体囊肿的上皮细胞以及来自无ADPKD个体的正常人肾皮质（HKC）的上皮细胞。确定激动剂和抑制剂对细胞增殖速率以及细胞外信号调节激酶（ERK1/2）激活的影响。
8-溴-cAMP（100微摩尔/升）将来自8名不同ADPKD受试者的细胞增殖刺激至比基线高99.0%；蛋白激酶A（PKA）拮抗剂H-89（97%）和Rp-cAMP（90%）抑制了增殖。激活腺苷酸环化酶的福斯可林（10微摩尔/升）使增殖增加124%，受体介导的激动剂精氨酸加压素、去氨加压素、促胰液素、血管活性肠肽和前列腺素E2分别刺激增殖54.2%、56.3%、46.7%、37.1%和48.3%。丝裂原细胞外激酶（MEK）抑制剂PD98059完全抑制了ADPKD细胞对cAMP激动剂的增殖反应，但受体酪氨酸激酶抑制剂染料木黄酮并未阻断cAMP依赖性增殖。cAMP激动剂在5分钟内使ERK活性高于对照水平。与ADPKD相反，尽管这些激动剂在ADPKD和HKC细胞单层中均增加了电致性Cl-分泌，但来自正常HKC的细胞增殖和ERK活性并未受到cAMP激动剂的刺激。
我们得出结论，cAMP激动剂通过在受体酪氨酸激酶远端位点激活ERK途径来刺激ADPKD而非HKC上皮细胞的增殖。我们认为腺苷酸环化酶信号通路可能通过刺激细胞增殖以及跨上皮溶质和液体分泌，在决定ADPKD囊肿增大速率方面具有独特作用。
