1 Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University , London, Canada .
2 Molecular Medicine Research Laboratories, Krembil Centre for Stem Cell Biology, Robarts Research Institute , London, Canada .
Stem Cells Dev. 2018 Oct 15;27(20):1449-1461. doi: 10.1089/scd.2018.0111. Epub 2018 Sep 5.
Islet regeneration is stimulated after transplantation of human umbilical cord blood (UCB) hematopoietic progenitor cells with high aldehyde dehydrogenase (ALDH)-activity into NOD/SCID mice with streptozotocin (STZ)-induced β cell ablation. ALDH progenitor cells represent a rare subset within UCB that will require expansion without the loss of islet regenerative functions for use in cell therapies. ALDH cells efficiently expand (>70-fold) under serum-free conditions; however, high ALDH-activity is rapidly diminished during culture coinciding with emergence of a committed megakaryocyte phenotype CD41+/CD42+/CD38+. ALDH-activity is also the rate-limiting step in retinoic acid (RA) production, a potent driver of hematopoietic differentiation. We have previously shown that inhibition of RA production during 9-day cultures, using diethylaminobenzaldehyde (DEAB) treatment, enhanced the expansion of ALDH cells (>20-fold) with vascular regenerative paracrine functions. Herein, we sought to determine if DEAB-treatment also expanded ALDH cells that retain islet regenerative function following intrapancreatic transplantation into hyperglycemic mice. After DEAB-treatment, expanded ALDH cell subset was enriched for CD34+/CD38- expression and demonstrated enhanced myeloid multipotency in vitro compared to the ALDH cell subset. Unfortunately, DEAB-treated ALDH cells did not support islet regeneration after transplantation. Conversely, expanded ALDH cells from DEAB-treated conditions reduced hyperglycemia, and increased islet number and cell proliferation in STZ-induced hyperglycemic NOD/SCID mice. DEAB-treated ALDH cells were largely committed to a CD41+/CD42+ megakaryocyte phenotype. Collectively, this study provides preliminary evidence that committed cells of the megakaryocyte-lineage support endogenous islet regeneration and/or function, and the retention of high ALDH-activity did not coincide with islet regenerative function after expansion under serum-free culture conditions.
人脐血（UCB）高醛脱氢酶（ALDH）-活性造血祖细胞移植到链脲佐菌素（STZ）诱导的β细胞消融的 NOD/SCID 小鼠中可刺激胰岛再生。ALDH 祖细胞是 UCB 中罕见的亚群，在用于细胞治疗之前，需要在不丧失胰岛再生功能的情况下进行扩增。ALDH 细胞在无血清条件下有效扩增（>70 倍）；然而，在培养过程中，高 ALDH 活性迅速降低，同时出现了一种定向的巨核细胞表型 CD41+/CD42+/CD38+。ALDH 活性也是视黄酸（RA）产生的限速步骤，RA 是造血分化的有力驱动因素。我们之前已经表明，使用二乙氨基苯甲醛（DEAB）处理，在 9 天的培养过程中抑制 RA 的产生，可以增强 ALDH 细胞的扩增（>20 倍），同时具有血管再生旁分泌功能。在此，我们试图确定 DEAB 处理是否也可以扩增在高血糖小鼠胰岛内移植后保留胰岛再生功能的 ALDH 细胞。经过 DEAB 处理后，扩增的 ALDH 细胞亚群富含 CD34+/CD38-表达，并在体外表现出增强的髓样多能性，与 ALDH 细胞亚群相比。不幸的是，DEAB 处理的 ALDH 细胞在移植后不能支持胰岛再生。相反，来自 DEAB 处理条件的扩增的 ALDH 细胞可降低高血糖，并增加 STZ 诱导的高血糖 NOD/SCID 小鼠中的胰岛数量和细胞增殖。DEAB 处理的 ALDH 细胞主要定向于 CD41+/CD42+巨核细胞表型。总的来说，这项研究提供了初步证据表明巨核细胞谱系的定向细胞支持内源性胰岛再生和/或功能，并且在无血清培养条件下扩增时，高 ALDH 活性的保留与胰岛再生功能不一致。
