Don Rix Protein Identification Facility, Department of Biochemistry, Schulich School of Medicine & Dentistry, Western University, London, Ontario, Canada.
Krembil Centre for Stem Cell Biology, Molecular Medicine Research Laboratories, Robarts Research Institute, London, Ontario, Canada.
Stem Cells. 2019 Apr;37(4):516-528. doi: 10.1002/stem.2976. Epub 2019 Jan 30.
Human multipotent stromal cells (hMSC) can induce islet regeneration after transplantation via the secretion of proteins that establish an islet regenerative niche. However, the identity of hMSC-secreted signals and the mechanisms by which pancreatic islet regeneration is induced remain unknown. Recently, mammalian pancreatic α-cells have been shown to possess considerable plasticity, and differentiate into β-like cells after near complete β-cell loss or overexpression of key transcriptional regulators. These studies have generated new excitement that islet regeneration during diabetes may be possible if we can identify clinically applicable stimuli to modulate these key regulatory pathways. Herein, we demonstrate that intrapancreatic-injection of concentrated hMSC-conditioned media (CM) stimulated islet regeneration without requiring cell transfer. hMSC CM-injection significantly reduced hyperglycemia, increased circulating serum insulin concentration, and improved glucose tolerance in streptozotocin-treated mice. The rate and extent of endogenous β-cell mass recovery was dependent on total protein dose administered and was further augmented by the activation of Wnt-signaling using GSK3-inhibition during CM generation. Intrapancreatic hMSC CM-injection immediately set in motion a cascade of regenerative events that included the emergence of proliferating insulin clusters adjacent to ducts, NKX6.1 expression in glucagon cells at days 1-4 suggesting the acquisition of β-cell phenotype by α-cells, and accelerated β-cell maturation with increased MAFA-expression for >1 month postinjection. Discovery and validation of islet regenerative hMSC-secreted protein may lead to the development of cell-free regenerative therapies able to tip the balance in favor of β-cell regeneration versus destruction during diabetes. Stem Cells 2019;37:516-528.
人多能基质细胞（hMSC）可通过分泌建立胰岛再生龛位的蛋白来诱导移植后的胰岛再生。然而，hMSC 分泌的信号的身份以及诱导胰岛再生的机制仍不清楚。最近，哺乳动物胰腺α细胞已被证明具有相当大的可塑性，并且在β细胞几乎完全丢失或关键转录调节因子过表达后分化为β样细胞。这些研究产生了新的兴奋，即在糖尿病期间，如果我们能够确定可用于调节这些关键调节途径的临床适用刺激物，那么胰岛再生可能是可能的。在此，我们证明，在胰腺内注射浓缩的 hMSC 条件培养基（CM）可刺激胰岛再生，而无需细胞转移。hMSC CM 注射可显著降低高血糖，增加循环血清胰岛素浓度，并改善链脲佐菌素处理的小鼠的葡萄糖耐量。内源性β细胞质量恢复的速度和程度取决于给予的总蛋白剂量，并且在 CM 生成过程中使用 GSK3 抑制激活 Wnt 信号进一步增强。胰腺内 hMSC CM 注射立即引发了一系列再生事件，包括在导管附近出现增殖的胰岛素簇，在第 1-4 天在胰高血糖素细胞中表达 NKX6.1，提示α细胞获得β细胞表型，以及加速β细胞成熟，MAFA 表达增加超过 1 个月。发现和验证胰岛再生 hMSC 分泌蛋白可能导致开发无细胞再生治疗方法，能够在糖尿病期间有利于β细胞再生而不是破坏的平衡。干细胞 2019;37:516-528.
