Background: Heme oxygenase-1 (HO-1) is an inducible enzyme that affords cytoprotection in reaction to cellular stress and tissue damage. To study the in vivo regulation of human HO-1 gene expression at the molecular level, our laboratory previously generated HO-1 transgenic (hBAC mice) mice that lack murine HO-1 gene and overexpress a human HO-1 transgene on a BAC or bacterial artificial chromosome. The human HO-1 levels in the basal state in various tissues including the kidneys were significantly elevated in hBAC mice compared to HO-1 wild type (WT) mice. Previously, microRNAs or miRNAs have been reported to be involved in the regulation of HO-1 by binding to the 3’ untranslated region or UTR of the gene. In our current study, we sought to examine the role of miRNAs in the regulation HO-1 expression in primary proximal tubule cells (PTCs) isolated from the kidneys of hBAC mice. Methods: Primary PTCs were isolated from the kidneys of hBAC mice and treated with four different miRNAs predicted by online web algorithms to bind to the 3’ UTR of HO-1. We used bioinformatics analyses, real time polymerase chain reaction (PCR) and western blot protein analyses to examine the regulation of HO-1 expression by miRNAs in hBAC PTCs. Results: miRNAs 217, 377, 485, and 873 were predicted to bind to the 3’ UTR of the human HO-1 gene. No significant differences were found in HO-1 mRNA levels in PTCs that were isolated from hBAC mice and treated with these miRNA mimics. This indicates that these miRNAs do not affect the stability of mRNA transcripts of HO-1.miR-217 significantly reduced HO-1 protein expression levels in PTCs isolated from hBAC mice. Conclusion: These studies indicate that miRNAs regulate the expression of HO-1 in PTCs and suggest that these mice represent an important tool for elucidating the mechanisms that control HO-1 expression in pathological conditions including acute kidney injury (AKI) to potentiate its protective effects.
Boddu, Ravindra; Hull, Travis D.; Joseph, Reny; Traylor, Amie M.; and Agarwal, Anupam
"miR-217 Regulates Heme Oxygenase-1 Expression in ‘Humanized’ Renal Proximal Tubular Cells,"
Manipal Journal of Medical Sciences: Vol. 1
, Article 2.
Available at: https://impressions.manipal.edu/mjms/vol1/iss1/2