Caveolin-1 scaffolding domain peptide regulates glucose metabolism in lung fibrosis
Venkadesaperumal Gopu, Liang Fan, Rashmi S. Shetty, M.R. Nagaraja, Sreerama Shetty
Venkadesaperumal Gopu, Liang Fan, Rashmi S. Shetty, M.R. Nagaraja, Sreerama Shetty
View: Text | PDF
Research Article Pulmonology

Caveolin-1 scaffolding domain peptide regulates glucose metabolism in lung fibrosis

Abstract

Increased metabolism distinguishes myofibroblasts or fibrotic lung fibroblasts (fLfs) from the normal lung fibroblasts (nLfs). The mechanism of metabolic activation in fLfs has not been fully elucidated. Furthermore, the antifibrogenic effects of caveolin-1 scaffolding domain peptide CSP/CSP7 involving metabolic reprogramming in fLfs are unclear. We therefore analyzed lactate and succinate levels, as well as the expression of glycolytic enzymes and hypoxia inducible factor-1α (HIF-1α). Lactate and succinate levels, as well as the basal expression of glycolytic enzymes and HIF-1α, were increased in fLfs. These changes were reversed following restoration of p53 or its transcriptional target microRNA-34a (miR-34a) expression in fLfs. Conversely, inhibition of basal p53 or miR-34a increased glucose metabolism, glycolytic enzymes, and HIF-1α in nLfs. Treatment of fLfs or mice having bleomycin- or Ad-TGF-β1–induced lung fibrosis with CSP/CSP7 reduced the expression of glycolytic enzymes and HIF-1α. Furthermore, inhibition of p53 or miR-34a abrogated CSP/CSP7-mediated restoration of glycolytic flux in fLfs in vitro and in mice with pulmonary fibrosis and lacking p53 or miR-34a expression in fibroblasts in vivo. Our data indicate that dysregulation of glucose metabolism in fLfs is causally linked to loss of basal expression of p53 and miR-34a. Treatment with CSP/CSP7 constrains aberrant glucose metabolism through restoration of p53 and miR-34a.

Authors

Venkadesaperumal Gopu, Liang Fan, Rashmi S. Shetty, M.R. Nagaraja, Sreerama Shetty

×

Figure 3

Regulation of glucose metabolism by miR-34a in fLfs.

Options: View larger image (or click on image) Download as PowerPoint
Regulation of glucose metabolism by miR-34a in fLfs. (A) hfLfs were tran...
(A) hfLfs were transduced with lentivirus-expressing empty vector (Lv-Ev) or –precursor–miR-34a (Lv–Pre–miR-34a) to overexpress miR-34a. Naive hnLfs and hfLfs were used as controls. After 48 hours of infection, total cell extracts were analyzed for HK2, PFKP, PKM, PFKFB3, and HIF-1α by immunoblotting. Images are representative of 2 independent experiments. (B) Total RNA isolated from n = 4 naive hnLf and hfLfs, or hfLfs transduced with Lv-Ev or Lv–Pre–miR-34a as in A, was analyzed for HK2, PFKP, PKM, PFKFB3, and HIF1A by qPCR (n = 4). (C) hnLfs were transduced with Lv-Ev or Lv-expressing miR-34a antisense (Lv–miR-34a–As). Naive hnLfs and hfLfs were used as controls. After 48 hours of infection, the cell lysates were analyzed for the expression of HK2, PFKP, PKM, PFKFB3, and HIF-1α by Western blotting. The representative images of 2 independent experiments are shown. (D) Total RNA isolated from n = 4 naive hnLfs or hfLfs, or hnLfs transduced with Lv-Ev or Lv–miR-34a–As as in C, was tested for HK2, PFKP, PKM, PFKFB3, and HIF1A mRNA by qPCR (n = 4). Data represented as mean ± SD were analyzed by 1-way ANOVA followed by Tukey’s post hoc test. **P < 0.01, ***P < 0.001, ****P < 0.0001.