Hedgehog interacting protein (HHIP) represses airway remodeling and metabolic reprogramming in COPD-derived airway smooth muscle cells

Yan Li,Taotao Lao,Betty Pham,Yuan Hao,Shuang Xu,Francesca Polverino,Feng Guo,Caroline A Owen,Li Zhang,Lijia Li,Xiaobo Zhou

doi:10.1038/s41598-021-88434-x

Abstract

Although HHIP locus has been consistently associated with the susceptibility to COPD including airway remodeling and emphysema in genome-wide association studies, the molecular mechanism underlying this genetic association remains incompletely understood. By utilizing Hhip+/- mice and primary human airway smooth muscle cells (ASMCs), here we aim to determine whether HHIP haploinsufficiency increases airway smooth muscle mass by reprogramming glucose metabolism, thus contributing to airway remodeling in COPD pathogenesis. The mRNA levels of HHIP were compared in normal and COPD-derived ASMCs. Mitochondrial oxygen consumption rate and lactate levels in the medium were measured in COPD-derived ASMCs with or without HHIP overexpression as readouts of glucose oxidative phosphorylation and aerobic glycolysis rates. The proliferation rate was measured in healthy and COPD-derived ASMCs treated with or without 2-DG. Smooth muscle mass around airways was measured by immunofluorescence staining for α-smooth muscle actin (α-SMA) in lung sections from Hhip+/- mice and their wild type littermates, Hhip+/+ mice. Airway remodeling was assessed in Hhip+/- and Hhip+/- mice exposed to 6 months of cigarette smoke. Our results show HHIP inhibited aerobic glycolysis and represses cell proliferation in COPD-derived ASMCs. Notably, knockdown of HHIP in normal ASMCs increased PKM2 activity. Importantly, Hhip+/- mice demonstrated increased airway remodeling and increased intensity of α-SMA staining around airways compared to Hhip+/+ mice. In conclusion, our findings suggest that HHIP represses aerobic glycolysis and ASMCs hyperplasia, which may contribute to the increased airway remodeling in Hhip+/- mice.

Highlights

Chronic obstructive pulmonary disease (COPD) ranks as the third leading cause of global d eath[1]
To examine the metabolic reprogramming from oxidative phosphorylation (OXPHOS) to aerobic glycolysis in COPD-derived airway smooth muscle cells (ASMCs), seahorse mitostress assay was performed, demonstrating decreased basal oxygen consumption rate (OCR) in COPD-derived ASMCs compared to normal ASMCs (Fig. 1A and B)
These results suggested the reprogramming of glucose metabolism from OXPHOS to aerobic glycolysis (Warburg effects) in COPD-derived ASMCs

Summary

Introduction

Chronic obstructive pulmonary disease (COPD) ranks as the third leading cause of global d eath[1]. Relatively few studies have been performed to investigate metabolic changes in COPD pathogenesis We showed another COPD GWAS gene, FAM13A, promoted fatty acid-oxidation in airway epithelial cells that might contribute to cigarette smoke-induced cell death during emphysema development[24], suggesting the importance of genetic factors in regulating cellular metabolism during COPD development. The correlation between this glucose metabolic shift from oxidative phosphorylation (OXPHOS) to aerobic glycolysis and increased proliferation in COPD-derived ASMCs have not been assessed. The current study investigates whether HHIP, the COPD GWAS gene, regulates glucose metabolic reprogramming and the biological consequence of such metabolic changes in ASMCs. we hypothesize that HHIP protects ASMCs from metabolic reprogramming towards aerobic glycolysis, preventing airway remodeling by inhibiting ASMC hyperplasia in COPD pathogenesis. Lower HHIP expression in COPD ASMCs are associated with increased aerobic glycolysis-mediated cell hyperproliferation

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