Tsuboi Y, Shankland S J, Grande J P, Walker H J, Johnson R J, Dousa T P
Renal Pathophysiology Laboratory, Department of Physiology and Biophysics, Mayo Clinic and Mayo Medical School, Rochester, Minnesota 55905, USA.
J Clin Invest. 1996 Jul 15;98(2):262-70. doi: 10.1172/JCI118788.
Excessive mesangial cell (MC) proliferation is a hallmark of many glomerulopathies. In our recent study on cultured rat MC (Matousovic, K., J.P. Grande, C.C.S. Chini, E.N. Chini, and T.P. Dousa. 1995. J. Clin. Invest. 96:401-410) we found that inhibition of isozyme cyclic-3',5'-nucleotide phosphodiesterase (PDE) type III (PDE-III) suppressed MC mitogenesis by activating cAMP-dependent protein kinase (PKA) and by decreasing activity of mitogen-activated protein kinase (MAPK). We also found that inhibition of another PDE isozyme, PDE-IV, suppresses superoxide generation in glomeruli (Chini, C.C.S., E.N. Chini, J.M. Williams, K. Matousovic, and T.P. Dousa. 1994. Kidney Int. 46:28-36). We thus explored whether administration in vivo of the selective PDE-III antagonist, lixazinone (LX), together with the specific PDE-IV antagonist, rolipram (RP), can attenuate development of mesangioproliferative glomerulonephritis (MSGN) induced in rats by anti-rat thymocyte serum (ATS). Unlike the vehicle-treated MSGN rats, rats with MSGN treated with LX and RP did not develop proteinuria and maintained normal renal function when examined 5 d after injection of ATS. In PAS-stained kidneys from PDE-antagonists-treated MSGN-rats the morphology of glomeruli showed a reduction in cellularity compared with control rats with ATS. Compared with MSGN rats receiving vehicle, the MSGN rats receiving PDE-antagonists had less glomerular cell proliferation (PCNA delta -65%), a significantly lesser macrophage infiltration (delta -36% ED-1) and a significant reduction of alpha-smooth muscle actin expression by activated MC; in contrast, immunostaining for platelet antigens and laminin were not different. The beneficial effect of PDE inhibitors was not due to a moderate decrease (approximately -20%) in systolic blood pressure (SBP); as a similar decrease in SBP due to administration of hydralazine, a drug devoid of PDE inhibitory effect, did not reduce severity of MSGN in ATS-injected rats. We conclude that antagonists of PDE-III and PDE-IV administered in submicromolar concentrations in vivo to ATS-injected rats can decrease the activation and proliferation of MC, inhibit the macrophage accumulation, and prevent proteinuria in the acute phase of MSGN. We propose that PDE isozyme inhibitors act to block (negative "crosstalk") the mitogen-stimulated intracellular signaling pathway which controls MC proliferation due to activating of the cAMP-PKA pathway. These results suggest that antagonists of PDE-111 and IV may have a suppressive effect in acute phases or relapses of glomerulopathies associated with MC proliferations.
系膜细胞（MC）过度增殖是许多肾小球疾病的一个标志。在我们最近对培养的大鼠MC的研究中（Matousovic, K., J.P. Grande, C.C.S. Chini, E.N. Chini, and T.P. Dousa. 1995. J. Clin. Invest. 96:401 - 410），我们发现抑制同工酶环3',5'-核苷酸磷酸二酯酶（PDE）III型（PDE-III）可通过激活cAMP依赖性蛋白激酶（PKA）并降低丝裂原活化蛋白激酶（MAPK）的活性来抑制MC的有丝分裂。我们还发现抑制另一种PDE同工酶PDE-IV可抑制肾小球中超氧化物的产生（Chini, C.C.S., E.N. Chini, J.M. Williams, K. Matousovic, and T.P. Dousa. 1994. Kidney Int. 46:28 - 36）。因此，我们探讨了在体内给予选择性PDE-III拮抗剂利扎嗪酮（LX）与特异性PDE-IV拮抗剂咯利普兰（RP），是否能减轻抗大鼠胸腺细胞血清（ATS）诱导的大鼠系膜增生性肾小球肾炎（MSGN）的发展。与给予赋形剂处理的MSGN大鼠不同，用LX和RP处理的MSGN大鼠在注射ATS后5天检查时未出现蛋白尿，并维持了正常的肾功能。在PDE拮抗剂处理的MSGN大鼠的PAS染色肾脏中，与接受ATS的对照大鼠相比，肾小球形态显示细胞数量减少。与接受赋形剂的MSGN大鼠相比，接受PDE拮抗剂的MSGN大鼠肾小球细胞增殖较少（PCNA降低-65%），巨噬细胞浸润明显减少（ED-1降低-36%），活化的MC中α-平滑肌肌动蛋白表达显著降低；相反，血小板抗原和层粘连蛋白的免疫染色没有差异。PDE抑制剂的有益作用并非由于收缩压（SBP）适度降低（约-20%）；因为给予无PDE抑制作用的药物肼屈嗪导致的SBP类似降低并未减轻注射ATS的大鼠中MSGN的严重程度。我们得出结论，体内以亚微摩尔浓度给予注射ATS的大鼠PDE-III和PDE-IV拮抗剂可减少MC的活化和增殖，抑制巨噬细胞积聚，并预防MSGN急性期的蛋白尿。我们提出PDE同工酶抑制剂通过激活cAMP-PKA途径来阻断（负性“串扰”）控制MC增殖的丝裂原刺激的细胞内信号通路。这些结果表明，PDE-III和IV的拮抗剂可能对与MC增殖相关的肾小球疾病的急性期或复发具有抑制作用。
