Scuto Maria, Trovato Salinaro Angela, Modafferi Sergio, Polimeni Alessandra, Pfeffer Tilman, Weigand Tim, Calabrese Vittorio, Schmitt Claus Peter, Peters Verena
Department of Biomedical and Biotechnological Sciences, University of Catania, 95124 Catania, Italy.
Centre for Pediatric and Adolescent Medicine, University of Heidelberg, 69117 Heidelberg, Germany.
Biomedicines. 2020 Jun 26;8(6):177. doi: 10.3390/biomedicines8060177.
Carnosine improves diabetic complications, including diabetic nephropathy, in in vivo models. To further understand the underlying mechanism of nephroprotection, we studied the effect of carnosine under glucose-induced stress on cellular stress response proteins in murine immortalized podocytes, essential for glomerular function. High-glucose stress initiated stress response by increasing intracellular heat shock protein 70 (Hsp70), sirtuin-1 (Sirt-1), thioredoxin (Trx), glutamate-cysteine ligase (gamma-glutamyl cysteine synthetase; γ-GCS) and heme oxygenase-1 (HO-1) in podocytes by 30-50% compared to untreated cells. Carnosine (1 mM) also induced a corresponding upregulation of these intracellular stress markers, which was even more prominent compared to glucose for Hsp70 (21%), γ-GCS and HO-1 (13% and 20%, respectively; all < 0.001). Co-incubation of carnosine (1 mM) and glucose (25 mM) induced further upregulation of Hsp70 (84%), Sirt-1 (52%), Trx (35%), γ-GCS (90%) and HO-1 (73%) concentrations compared to untreated cells (all < 0.001). The glucose-induced increase in 4-hydroxy--2-nonenal (HNE) and protein carbonylation was reduced dose-dependently by carnosine by more than 50% ( < 0.001). Although podocytes tolerated high carnosine concentrations (10 mM), high carnosine levels only slightly increased Trx and γ-GCS (10% and 19%, respectively, compared to controls; < 0.001), but not Hsp70, Sirt-1 and HO-1 proteins ( not significant), and did not modify the glucose-induced oxidative stress response. In podocytes, carnosine induced cellular stress tolerance and resilience pathways and was highly effective in reducing high-glucose-induced glycative and lipoperoxidative stress. Carnosine in moderate concentrations exerted a direct podocyte molecular protective action.
肌肽可改善体内模型中的糖尿病并发症，包括糖尿病肾病。为了进一步了解肾脏保护的潜在机制，我们研究了在葡萄糖诱导的应激条件下肌肽对小鼠永生化足细胞中细胞应激反应蛋白的影响，足细胞对肾小球功能至关重要。与未处理的细胞相比，高糖应激通过使足细胞内的热休克蛋白70（Hsp70）、沉默调节蛋白1（Sirt-1）、硫氧还蛋白（Trx）、谷氨酸-半胱氨酸连接酶（γ-谷氨酰半胱氨酸合成酶；γ-GCS）和血红素加氧酶-1（HO-1）增加30%-50%来引发应激反应。肌肽（1 mM）也诱导了这些细胞内应激标志物的相应上调，与葡萄糖相比，Hsp70（21%）、γ-GCS和HO-1（分别为13%和20%；均P<0.001）的上调更为显著。与未处理细胞相比，肌肽（1 mM）和葡萄糖（25 mM）共同孵育诱导Hsp70（84%）、Sirt-1（52%）、Trx（35%）、γ-GCS（90%）和HO-1（73%）浓度进一步上调（均P<0.001）。肌肽以剂量依赖性方式将葡萄糖诱导的4-羟基-2-壬烯醛（HNE）和蛋白质羰基化增加降低了50%以上（P<0.001）。尽管足细胞能够耐受高浓度的肌肽（10 mM），但高浓度的肌肽仅轻微增加Trx和γ-GCS（与对照组相比分别增加10%和19%；P<0.001），而不增加Hsp70、Sirt-1和HO-1蛋白（无显著性差异），并且不会改变葡萄糖诱导的氧化应激反应。在足细胞中，肌肽诱导细胞应激耐受和恢复途径，并且在减轻高糖诱导的糖基化和脂质过氧化应激方面非常有效。中等浓度的肌肽对足细胞发挥直接的分子保护作用。
