757 miR-98 Regulates GH Pathway during Stress-Impaired Wound Healing

Friday, March 23, 2012: 10:45 a.m. - 12:15 p.m.
Presentation Type: Oral Session
S.D. TYMEN1, Z.J. FANG1, Y. ZHAO1, S. JAHEDI2, and P. MARUCHA1, 1Periodontics, Center for Wound Healing and Tissue Regeneration, University of Illinois - Chicago, Chicago, IL, 2University of Illinois - Chicago, Chicago, IL

Stress delays wound healing and impairs bacterial clearance at the wound site, increasing the risk of opportunistic infection. The growth hormone receptor (GHR), a key element of the GH signaling pathway, is important in bacterial clearance, inflammation and tissue growth, and is a potential target of miR-98.  We hypothesize that stress induces differential expression of miR-98 that regulate GH pathway contributing to impaired inflammation and bacterial clearance and leading to poor tissue repair during wound healing.


SKH-1 mice were either food-and-water deprived (FWD) to serve as controls or stressed by restraint (RST) 12h/day for 3 days prior and 5 days post–wounding. Two punch biopsy wounds of 3.5mm were created on their backs. Wound sites were either non-treated or treated with 1uM LNA miR-98 inhibitor or scrambled sequence prior to and the day of surgery. Pictures of the wounds were taken every day for photoplanimetry. Wounds were harvested for each condition 0, 1 and 5 days post-wounding and processed for qRT-PCR (n=20) to determine the expression of miR-98, its mRNA target GHR and down-stream genes activated by GH pathway such as IGF-1.


We observed that stress up-regulated miR-98 levels at D1 by 38 fold (p<0.05) and D5 (p=0.058), which was associated with lower expression of GHR by 3 fold (p<0.1) and IGF-1 by 3 fold (p<0.05) at D1. Inhibition of miR-98 with LNA-miR-98 ameliorated wound closure (p<0.05), decreased miR-98 level to 3 folds and augmented gene expression of GHR and IGF-1. 


Our study suggests that miR-98 overexpression by RST inhibits GH pathway through down-regulation of GHR. Inhibition of miR-98 improved stress-impaired wound healing and reestablished the gene expression of GHR demonstrating GH as a pathway important in regulating wound healing and the therapeutical potential for miR-98 inhibitor.

This abstract is based on research that was funded entirely or partially by an outside source: NIH/NIDCR R01 DE017686

Keywords: Hormones and growth factors, Inflammation, Stress, Wound healing and miR-98