Regulatory role of miR-146a in corneal epithelial wound healing via its inflammatory targets in human diabetic cornea.
Adam J Poe, Ruchi Shah, Drirh Khare, Mangesh Kulkarni, Hong Phan, Sean Ghiam, Vasu Punj, Alexander V Ljubimov, Mehrnoosh Saghizadeh
Author Information
Adam J Poe: Eye Program, Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA.
Ruchi Shah: Eye Program, Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA.
Drirh Khare: Eye Program, Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA.
Mangesh Kulkarni: Eye Program, Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA.
Hong Phan: Eye Program, Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA; David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
Sean Ghiam: Eye Program, Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA; David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
Vasu Punj: Department of Medicine, University of Southern California, Los Angeles, CA, USA.
Alexander V Ljubimov: Eye Program, Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA; Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA; David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
Mehrnoosh Saghizadeh: Eye Program, Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA; Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA; David Geffen School of Medicine at UCLA, Los Angeles, CA, USA. Electronic address: ghiamm@cshs.org.
PURPOSE: MiR-146a upregulated in limbus vs. central cornea and in diabetic vs. non-diabetic limbus has emerged as an important immune and inflammatory signaling mediator in corneal epithelial wound healing. Our aim was to investigate the potential inflammation-related miR-146a target genes and their roles in normal and impaired diabetic corneal epithelial wound healing. METHODS: Our previous data from RNA-seq combined with quantitative proteomics of limbal epithelial cells (LECs) transfected with miR-146a mimic vs. mimic control were analyzed. Western blot and immunostaining were used to confirm the expression of miR-146a inflammatory target proteins in LECs and organ-cultured corneas. Luminex assay was performed on conditioned media at 6- and 20-h post-wounding in miR-146a mimic/inhibitor transfected normal and diabetic cultured LECs. RESULTS: Overexpression of miR-146a decreased the expression of pro-inflammatory TRAF6 and IRAK1 and downstream target NF-κB after challenge with lipopolysaccharide (LPS) or wounding. Additionally, miR-146a overexpression suppressed the production of downstream inflammatory mediators including secreted cytokines IL-1α, IL-1β, IL-6 and IL-8, and chemokines CXCL1, CXCL2 and CXCL5. These cytokines and chemokines were upregulated in normal but not in diabetic LEC during wounding. Furthermore, we achieved normalized levels of altered secreted cytokines and chemokines in diabetic wounded LEC via specific inhibition of miR-146a. CONCLUSION: Our study documented significant impact of miR-146a on the expression of inflammatory mediators at the mRNA and protein levels during acute inflammatory responses and wound healing, providing insights into the regulatory role of miR-146a in corneal epithelial homeostasis in normal and diabetic conditions.
