Refractory wounds in diabetic patients often result in amputation. Endothelial progenitors cells (EPC) actively participate in wound repair through angiogenesis after homing to the wounding site. However, EPC functions are impaired in diabetes with mechanisms poorly understood. Our pilot studies demonstrate a reduced activity of an important ER sensor ER sensor, Inositol requiring enzyme 1 (IRE1), and a decreased expression of a potent angiogenic factor angiopoietin-1 (ANGPT1) in EPCs from human and mice with type 2 diabetes, contribute to EPC dysfunction. Most importantly, our preliminary studies show that IRE1? suppresses a subset of microRNA (miR) clusters known to be detrimental to angiogenesis. We speculate that this suppression is due to IRE1?'s direct splicing activity to precursor miRs (pre-miRs), resulting in depletion of functional miRs. Of particular interest, our preliminary data demonstrate that IRE1? deficiency significantly increased miR-200 family in EPCs from diabetic mice, leading to down-regulation of one of their target genes - ANGPT1. Yet how IRE1 regulates EPC function and wound repair in diabetes is unknown. Therefore, the objective in this proposal is to determine the mechanisms of IRE1 regulation of angiogenesis and wound repair. The hypothesis, built upon our extensive preliminary studies and published work, is that deficiency in IRE1?, leads to insufficient degradation of pre-miRNA in diabetes, resulting in impaired endothelial progenitor cell (EPC) angiogenesis and delayed wound healing. Our hypothesis will be tested in three specific aims: 1) Determine the molecular mechanisms underlying the essential role of IRE1? in maintaining EPC function in diabetes in vitro; 2) Determine how IRE1?-targeted pre-miR modulates EPC function in vitro; 3) Determine how IRE1? improves wound healing in diabetes in vivo. Our approaches encompass in vitro and in vivo studies utilizing adenovirus-mediated gene manipulations, whole genome RNA profiling, IRE1? floxed mice and newly generated endothelium-specific IRE1? knockout mice. Furthermore, human EPCs will be obtained from type 2 diabetic patients and healthy subjects in order to determine the levels of IRE1? pathway and miRs. The proposed study is significant, because it will uncover a previously unrecognized role of the ER stress response in impaired angiogenesis and wound healing in diabetes at the translational level. The investigation of IRE1?-mediated regulation of stress miRs will open a new paradigm for the study of the molecular mechanisms responsible for pathogenesis of refractory wounds, which will enable future development of therapeutics for this devastating situation affecting millions of Americans.

Public Health Relevance

The proposed research is relevant to public healthy because it explores a novel regulatory role of stress response protein in new vessel formation that critically contributes to tissue repair in type 2 diabetics. The expectant outcome from this study may provide an important knowledge basis to stimulate the progenitor cell- based therapy in treating wounds under diabetic conditions, and ultimately protecting and improving health of millions of Americans.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK109036-02
Application #
9222758
Study Section
Surgery, Anesthesiology and Trauma Study Section (SAT)
Program Officer
Jones, Teresa L Z
Project Start
2016-03-01
Project End
2021-02-28
Budget Start
2017-03-01
Budget End
2018-02-28
Support Year
2
Fiscal Year
2017
Total Cost
$311,850
Indirect Cost
$109,350
Name
Wayne State University
Department
Genetics
Type
Schools of Medicine
DUNS #
001962224
City
Detroit
State
MI
Country
United States
Zip Code
48202
Farooq, Shukkur M; Hou, Yuning; Li, Hainan et al. (2018) Disruption of GPR35 Exacerbates Dextran Sulfate Sodium-Induced Colitis in Mice. Dig Dis Sci 63:2910-2922
Wang, Jie-Mei; Qiu, Yining; Yang, Zhao et al. (2018) IRE1? prevents hepatic steatosis by processing and promoting the degradation of select microRNAs. Sci Signal 11:
Wang, Jie-Mei; Qiu, Yining; Yang, Zeng-Quan et al. (2017) Inositol-Requiring Enzyme 1 Facilitates Diabetic Wound Healing Through Modulating MicroRNAs. Diabetes 66:177-192
Li, Hainan; Liu, Jenny; Wang, Yihan et al. (2017) MiR-27b augments bone marrow progenitor cell survival via suppressing the mitochondrial apoptotic pathway in Type 2 diabetes. Am J Physiol Endocrinol Metab 313:E391-E401
Wang, Jie-Mei; Chen, Alex F; Zhang, Kezhong (2016) Isolation and Primary Culture of Mouse Aortic Endothelial Cells. J Vis Exp :