Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama City University, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004, Japan.
Islet Cell and Regenerative Biology, Joslin Diabetes Center, Department of Medicine, Brigham and Women's Hospital, Harvard Stem Cell Institute, Harvard Medical School, Boston, MA, USA.
Diabetologia. 2020 Mar;63(3):577-587. doi: 10.1007/s00125-019-05071-w. Epub 2020 Jan 3.
AIMS/HYPOTHESIS: Sodium-glucose cotransporter 2 (SGLT2) inhibitors, which prevent the renal reabsorption of glucose, decrease blood glucose levels in an insulin-independent manner. We previously reported creating a mouse model of systemic inhibition of target receptors for both insulin and IGF-1 by treating animals with OSI-906, a dual insulin/IGF-1 receptor inhibitor, for 7 days. The OSI-906-treated mice exhibited an increased beta cell mass, hepatic steatosis and adipose tissue atrophy, accompanied by hyperglycaemia and hyperinsulinaemia. In the present study, we investigated the effects of an SGLT2 inhibitor, luseogliflozin, on these changes in OSI-906-treated mice.
We treated C57BL/6J male mice either with vehicle, luseogliflozin, OSI-906 or OSI-906 plus luseogliflozin for 7 days, and phenotyping was performed to determine beta cell mass and proliferation. Subsequently, we tested whether serum-derived factors have an effect on beta cell proliferation in genetically engineered beta cells, mouse islets or human islets.
SGLT2 inhibition with luseogliflozin significantly ameliorated hyperglycaemia, but not hyperinsulinaemia, in the OSI-906-treated mice. Liver steatosis and adipose tissue atrophy induced by OSI-906 were not altered by treatment with luseogliflozin. Beta cell mass and proliferation were further increased by SGLT2 inhibition with luseogliflozin in the OSI-906-treated mice. Luseogliflozin upregulated gene expression related to the forkhead box M1 (FoxM1)/polo-like kinase 1 (PLK1)/centromere protein A (CENP-A) pathway in the islets of OSI-906-treated mice. The increase in beta cell proliferation was recapitulated in a co-culture of Irs2 knockout and Insr/IR knockout (βIRKO) beta cells with serum from both luseogliflozin- and OSI-906-treated mice, but not after SGLT2 inhibition in beta cells. Circulating factors in both luseogliflozin- and OSI-906-treated mice promoted beta cell proliferation in both mouse islets and cadaveric human islets.
CONCLUSIONS/INTERPRETATION: These results suggest that luseogliflozin can increase beta cell proliferation through the activation of the FoxM1/PLK1/CENP-A pathway via humoral factors that act in an insulin/IGF-1 receptor-independent manner.
目的/假设：钠-葡萄糖共转运蛋白 2（SGLT2）抑制剂可阻止葡萄糖在肾脏中的重吸收，以不依赖胰岛素的方式降低血糖水平。我们之前曾报道过，通过用双重胰岛素/IGF-1 受体抑制剂 OSI-906 治疗动物 7 天，可创建一种系统抑制胰岛素和 IGF-1 靶受体的小鼠模型。用 OSI-906 治疗的小鼠表现出β细胞质量增加、肝脂肪变性和脂肪组织萎缩，伴有高血糖和高胰岛素血症。在本研究中，我们研究了 SGLT2 抑制剂 luseogliflozin 对 OSI-906 治疗小鼠这些变化的影响。
我们用载体、luseogliflozin、OSI-906 或 OSI-906 加 luseogliflozin 处理 C57BL/6J 雄性小鼠 7 天，并进行表型分析以确定β细胞质量和增殖。随后，我们测试了血清来源的因子是否对基因工程化的β细胞、小鼠胰岛或人胰岛中的β细胞增殖有影响。
用 luseogliflozin 抑制 SGLT2 可显著改善 OSI-906 治疗小鼠的高血糖症，但不能改善高胰岛素血症。OSI-906 诱导的肝脂肪变性和脂肪组织萎缩未被 luseogliflozin 治疗改变。在 OSI-906 治疗的小鼠中，用 luseogliflozin 抑制 SGLT2 进一步增加了β细胞质量和增殖。Luseogliflozin 上调了 OSI-906 治疗小鼠胰岛中与叉头框 M1（FoxM1）/丝氨酸/苏氨酸激酶 1（PLK1）/着丝粒蛋白 A（CENP-A）途径相关的基因表达。在 Irs2 敲除和 Insr/IR 敲除（βIRKO）β细胞与来自 luseogliflozin 和 OSI-906 治疗小鼠的血清的共培养中，β细胞增殖增加，但在β细胞中抑制 SGLT2 则不然。来自 luseogliflozin 和 OSI-906 治疗小鼠的循环因子可促进小鼠胰岛和尸体供体人胰岛中的β细胞增殖。
结论/解释：这些结果表明，luseogliflozin 可以通过激活 FoxM1/PLK1/CENP-A 途径增加β细胞增殖，这种途径通过以胰岛素/IGF-1 受体非依赖的方式发挥作用的体液因子来实现。
