Department of Biochemistry, School of Life Science and Technology, China Pharmaceutical University, Nanjing, China.
Fraser Laboratories for Diabetes Research, Department of Medicine, McGill University Health Centre, Montreal, Canada.
Diabetes Obes Metab. 2019 May;21(5):1209-1222. doi: 10.1111/dom.13644. Epub 2019 Mar 1.
The potential effect of regenerating (Reg) proteins in the treatment of diabetes has been indicated in the past decade, but the clinical use of Reg proteins requires more advances in translational medicine. In the present study, we produced recombinant regenerating protein 2 (rReg2), to prove its protective effect against streptozocin (STZ)-induced diabetes in BALB/c mice.
rReg2 was administrated in STZ-induced diabetic mice. Blood glucose, body weight, serum insulin and islet β-cell loss were determined. However, Reg2 has also been reported to serve as an autoantigen that induces autoimmune attacks on islets and aggravates diabetic development in non-obese diabetic mice. To address this contradiction, complete Freund's adjuvant was injected to generate a model that was hypersensitive to Reg2. In this model, islet CD8 T-cell infiltration, serum Reg2 antibody and interleukin (IL)-4 and IL-10, and splenic CD4+/interferon (IFN)-γ+ T cells were determined.
Direct rReg2 pretreatment preserved islet β-cell mass against STZ and improved glycaemia, body weight and serum insulin content. The protection against cell death was further confirmed in cultured mouse islets and MIN6 cells. On the other hand, significant elevations of serum Reg2 antibody and splenic CD4+/IFN-γ+ T cells, and decreases in serum IL-4 and IL-10 were detected in rReg2-vaccinated mice, which may contribute to the accelerated diabetes. Interestingly, these mice, upon further rReg2 treatment, exhibited alleviated diabetic conditions with less islet CD8+ T-cell infiltration.
rReg2 treatment ameliorated STZ-induced diabetes in normal BALB/c mice. By contrast, rReg2 vaccination exacerbated, but further rReg2 treatment alleviated, the severity of STZ-induced diabetes. Thus, the protective effect of rReg2 is predominant over the autoantigenic β-cell destruction, supporting the potential of rReg2 in the clinical treatment of diabetes.
在过去的十年中，再生（Reg）蛋白在糖尿病治疗中的潜在作用已经得到了证实，但 Reg 蛋白的临床应用需要在转化医学方面取得更多进展。在本研究中，我们生产了重组再生蛋白 2（rReg2），以证明其对 BALB/c 小鼠链脲佐菌素（STZ）诱导型糖尿病的保护作用。
rReg2 被给予 STZ 诱导的糖尿病小鼠。测定血糖、体重、血清胰岛素和胰岛β细胞丢失。然而，Reg2 也被报道为一种自身抗原，它会引发对胰岛的自身免疫攻击，并加重非肥胖型糖尿病小鼠的糖尿病发展。为了解决这一矛盾，我们用完全弗氏佐剂注射来产生对 Reg2 高度敏感的模型。在该模型中，测定胰岛 CD8 T 细胞浸润、血清 Reg2 抗体和白细胞介素（IL）-4 和 IL-10 以及脾 CD4+/干扰素（IFN）-γ+T 细胞。
直接 rReg2 预处理可防止 STZ 引起的胰岛β细胞减少，并改善血糖、体重和血清胰岛素含量。这种对细胞死亡的保护作用在培养的小鼠胰岛和 MIN6 细胞中也得到了进一步证实。另一方面，在 rReg2 疫苗接种小鼠中，检测到血清 Reg2 抗体和脾 CD4+/IFN-γ+T 细胞显著升高，血清 IL-4 和 IL-10 降低，这可能有助于加速糖尿病的发展。有趣的是，这些小鼠在进一步接受 rReg2 治疗后，胰岛 CD8+T 细胞浸润减少，糖尿病病情得到缓解。
rReg2 治疗改善了正常 BALB/c 小鼠的 STZ 诱导型糖尿病。相比之下，rReg2 疫苗接种加重了 STZ 诱导型糖尿病的严重程度，但进一步的 rReg2 治疗减轻了这种严重程度。因此，rReg2 的保护作用超过了自身抗原性β细胞破坏，支持 rReg2 在糖尿病临床治疗中的潜力。
