Chronic dietary energy stress on white adipose tissue (WAT) promotes fat deposition in peripheral tissues, whichacceleratesinsulinresistanceandtype2diabetesmellitus(T2DM).RestoringthecapacityofWATto safelysequesterexcessenergypromotesinsulinsensitivityinthefaceofdiet-inducedobesity.Tothisend,we discovered that the microRNA miR-30a exhibits reduced expression in subcutaneous fat from diabetic mice andhumanscomparedtonormalcontrols.OurpreliminarystudiesestablishthatmiR-30aconfersuponWAT theabilitytowithstandthepressureofhighfatdietandpreventtheco-morbiditiesofobesity.Thesechanges result in improved whole-body insulin sensitivity coupled with muted WAT inflammation and reduced hepatic steatosis.TheeffectofmiR-30aonWATfunctioncoincideswithcompleteblockadeofSTAT1signaling,which is a key transducer of obesity-linked inflammatory cytokines. These exciting studies support the hypothesis that systemic insulin sensitivity is preserved by miR-30a repression of STAT1-mediated inflammation in adipocytes.Intriguingly,miR-30aconfersbeneficialeffectsonglucoseandlipidhomeostasiswithoutreducing body weight. The goal of this proposal is to critically test our hypothesis by challenging our genetic mouse models of miR-30a and STAT1 expression with diet-induced obesity.
In Aim 1, we will define the basis underpinningthemetaboliceffectsofmiR-30atransgenicexpressioninWAT.
Aim2 willevaluatetheroleof the inflammatory transcription factor STAT1 in mediating the metabolic effects of miR-30a expression in subcutaneous WAT. Lastly, Aim 3 will establish the mechanisms governing the transcriptional regulation of miR-30a.OurinvestigationofthebasisbywhichmiR-30acontrolsWATfunctionissignificantbecauseitwill expand our understanding of mechanisms that connect obesity with T2DM. At the completion of our studies, we will have identified mechanisms that might be exploited in therapies to manage insulin resistance and T2DM.

Public Health Relevance

Insulin resistance and T2DM are chronic health problems in the United States. Mechanisms that improve insulin sensitivity by restoring proper fat storage mechanisms representnewparadigmsforclinicalmanagementofobesity.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK114356-02
Application #
9547843
Study Section
Molecular and Cellular Endocrinology Study Section (MCE)
Program Officer
Abraham, Kristin M
Project Start
2017-08-18
Project End
2022-05-31
Budget Start
2018-06-01
Budget End
2019-05-31
Support Year
2
Fiscal Year
2018
Total Cost
Indirect Cost
Name
Baylor College of Medicine
Department
Anatomy/Cell Biology
Type
Schools of Medicine
DUNS #
051113330
City
Houston
State
TX
Country
United States
Zip Code
77030
Zhao, Na; Cao, Jin; Xu, Longyong et al. (2018) Pharmacological targeting of MYC-regulated IRE1/XBP1 pathway suppresses MYC-driven breast cancer. J Clin Invest 128:1283-1299
Koh, Eun-Hee; Chernis, Natasha; Saha, Pradip K et al. (2018) miR-30a Remodels Subcutaneous Adipose Tissue Inflammation to Improve Insulin Sensitivity in Obesity. Diabetes 67:2541-2553
Villanueva, Hugo; Grimm, Sandra; Dhamne, Sagar et al. (2018) The Emerging Roles of Steroid Hormone Receptors in Ductal Carcinoma in Situ (DCIS) of the Breast. J Mammary Gland Biol Neoplasia 23:237-248
Morriss, Ginny R; Rajapakshe, Kimal; Huang, Shixia et al. (2018) Mechanisms of skeletal muscle wasting in a mouse model for myotonic dystrophy type 1. Hum Mol Genet 27:2789-2804
Szwarc, Maria M; Kommagani, Ramakrishna; Putluri, Vasanta et al. (2018) Steroid Receptor Coactivator-2 Controls the Pentose Phosphate Pathway through RPIA in Human Endometrial Cancer Cells. Sci Rep 8:13134