Jiménez-Palomares Margarita, López-Acosta José Francisco, Villa-Pérez Pablo, Moreno-Amador José Luis, Muñoz-Barrera Jennifer, Fernández-Luis Sara, Heras-Pozas Blanca, Perdomo Germán, Bernal-Mizrachi Ernesto, Cózar-Castellano Irene
Division of Metabolism, Endocrinology and Diabetes, University of Michigan, Ann Arbor, Michigan;
Instituto de Genética y Biología Molecular, Universidad de Valladolid-CSIC, Valladolid, Spain;
Am J Physiol Endocrinol Metab. 2015 Mar 15;308(6):E450-9. doi: 10.1152/ajpendo.00260.2014. Epub 2015 Jan 6.
Activation of pancreatic β-cell proliferation has been proposed as an approach to replace reduced functional β-cell mass in diabetes. Quiescent fibroblasts exit from G0 (quiescence) to G1 through pRb phosphorylation mediated by cyclin C/cdk3 complexes. Overexpression of cyclin D1, D2, D3, or cyclin E induces pancreatic β-cell proliferation. We hypothesized that cyclin C overexpression would induce β-cell proliferation through G0 exit, thus being a potential therapeutic target to recover functional β-cell mass. We used isolated rat and human islets transduced with adenovirus expressing cyclin C. We measured multiple markers of proliferation: [(3)H]thymidine incorporation, BrdU incorporation and staining, and Ki67 staining. Furthermore, we detected β-cell death by TUNEL, β-cell differentiation by RT-PCR, and β-cell function by glucose-stimulated insulin secretion. Interestingly, we have found that cyclin C increases rat and human β-cell proliferation. This augmented proliferation did not induce β-cell death, dedifferentiation, or dysfunction in rat or human islets. Our results indicate that cyclin C is a potential target for inducing β-cell regeneration.
激活胰腺β细胞增殖已被提议作为一种在糖尿病中替代功能减退的β细胞量的方法。静止的成纤维细胞通过细胞周期蛋白C/细胞周期蛋白依赖性激酶3（cdk3）复合物介导的视网膜母细胞瘤蛋白（pRb）磷酸化从G0期（静止期）进入G1期。细胞周期蛋白D1、D2、D3或细胞周期蛋白E的过表达可诱导胰腺β细胞增殖。我们假设细胞周期蛋白C的过表达将通过退出G0期诱导β细胞增殖，因此是恢复功能性β细胞量的一个潜在治疗靶点。我们使用了用表达细胞周期蛋白C的腺病毒转导的分离的大鼠和人类胰岛。我们测量了多种增殖标志物：[³H]胸腺嘧啶核苷掺入、5-溴脱氧尿嘧啶核苷（BrdU）掺入和染色以及Ki67染色。此外，我们通过末端脱氧核苷酸转移酶介导的缺口末端标记法（TUNEL）检测β细胞死亡，通过逆转录聚合酶链反应（RT-PCR）检测β细胞分化，通过葡萄糖刺激的胰岛素分泌检测β细胞功能。有趣的是，我们发现细胞周期蛋白C可增加大鼠和人类β细胞的增殖。这种增强的增殖并未在大鼠或人类胰岛中诱导β细胞死亡、去分化或功能障碍。我们的结果表明，细胞周期蛋白C是诱导β细胞再生的一个潜在靶点。
