Comparison of multipotency and molecular profile of MSCs between CKD and healthy rats
HUMAN CELL
Authors: Yamada, Akifumi; Yokoo, Takashi; Yokote, Shinya; Yamanaka, Shuichiro; Izuhara, Luna; Katsuoka, Yuichi; Shimada, Yohta; Shukuya, Akinori; Okano, Hirotaka James; Ohashi, Toya; Ida, Hiroyuki
Abstract
We previously showed that mesenchymal stem cells (MSCs) can differentiate into a functional miniature kidney, suggesting that MSCs may be a cell source for kidney regeneration. However, MSCs from long-term dialysis patients, which have been exposed to uremic toxin, can exhibit reduced viability. Therefore, the aim of this study was to examine the gene expression profiles and differentiation capabilities of bone marrow- and adipose-derived MSCs from chronic kidney disease (CKD) model rats. CKD was induced in rats by adenine feeding, and then MSCs were isolated from bone marrow (BMSCs) and adipose tissue (ASCs). After confirming MSC surface marker expression, comprehensive gene expression profiles were obtained by RT-PCR array. MSCs were differentiated into adipocytes, osteoblasts, and chondrocytes, and histological and/or functional assays were performed. Tgfb3 expression was up-regulated, while Bmp6, Gdf15, Mmp2, and Vegfa were down-regulated in CKD-ASCs compared with Control-ASCs. There were no significant differences in the gene expression of stemness markers, and the morphology of cells that underwent adipogenesis, osteogenesis, and chondrogenesis, or GPDH activity between CKD and control groups. Comparing BMSCs with ASCs, gene expression of Bglap, Bmp4, Igf1, Itgax, Pparg, Ptprc, and Tnf were up-regulated, while Col1a1, Mmp2, Sox9, and Vegfa were down-regulated in both CKD and control groups. Uremic toxin in CKD rats had a small effect on the gene expression and differentiation of MSCs. However, long-term exposure to uremic toxin and the differences in gene expression of MSCs derived from bone marrow or adipose tissue may affect renal regeneration.
Islet amyloid formation is an important determinant for inducing islet inflammation in high-fat-fed human IAPP transgenic mice
DIABETOLOGIA
Authors: Meier, Daniel T.; Morcos, Mary; Samarasekera, Thanya; Zraika, Sakeneh; Hull, Rebecca L.; Kahn, Steven E.
Abstract
Aims/hypothesis Amyloid deposition and inflammation are characteristic of islet pathology in type 2 diabetes. The aim of this study was to determine whether islet amyloid formation is required for the development of islet inflammation in vivo. Methods Human islet amyloid polypeptide transgenic mice and non-transgenic littermates (the latter incapable of forming islet amyloid) were fed a low-fat (10%) or high-fat (60%) diet for 12 months; high-fat feeding induces islet amyloid formation in transgenic mice. At the conclusion of the study, glycaemia, beta cell function, islet amyloid deposition, markers of islet inflammation and islet macrophage infiltration were measured. Results Fasting plasma glucose levels did not differ by diet or genotype. Insulin release in response to i.v. glucose was significantly greater in both high vs low fat groups, and significantly lower in both transgenic compared with non-transgenic groups. Only high-fat-fed transgenic mice developed islet amyloid and showed a trend towards reduced beta cell area. Compared with islets from low-fat-fed transgenic or high-fat-fed non-transgenic mice, islets of high-fat-fed transgenic mice displayed a significant increase in the expression of genes encoding chemokines (Ccl2, Cxcl1), macrophage/dendritic cell markers (Emr1, Itgax), NACHT, LRR and PYD domains-containing protein 3 (NLRP3) inflammasome components (Nlrp3, Pycard, Casp1) and proinflammatory cytokines (Il1b, Tnf, Il6), as well as increased F4/80 staining, consistent with increased islet inflammation and macrophage infiltration. Conclusions/interpretation Our results indicate that islet amyloid formation is required for the induction of islet inflammation in this long-term high-fat-diet model, and thus could promote beta cell dysfunction in type 2 diabetes via islet inflammation.