Identification and Functional Characterization of Hypoxia-Induced Endoplasmic Reticulum Stress Regulating lncRNA (HypERlnc)in Pericytes
Rationale: Pericytes are essential for vessel maturation and endothelial barrier function. Long non-coding RNAs (lncRNAs) regulate many cellular functions, but their role in pericyte biology remains unexplored.
Objective: Here we investigate the effect of Hypoxia-Induced Endoplasmic Reticulum Stress Regulating lncRNA (HypERlnc, also known as ENSG00000262454) on pericyte function in vitro and its regulation in human heart failure and idiopathic pulmonary arterial hypertension.
Methods and Results: RNA sequencing in human primary pericytes (hPCs) identified hypoxia regulated lncRNAs, including HypERlnc. Silencing of HypERlnc decreased cell viability, proliferation and resulted in pericyte de-differentiation, which went along with increased endothelial permeability in co-cultures consisting of hPC and human coronary microvascular endothelial cells. Consistently, Cas9-based transcriptional activation of HypERlnc was associated with increased expression of pericyte marker genes. Moreover, HypERlnc knockdown reduced endothelial-hPC recruitment in matrigel assays (P<0.05). Mechanistically, transcription factor reporter arrays demonstrated that endoplasmic reticulum stress related transcription factors were prominently activated upon HypERlnc knockdown, which was confirmed via immunoblotting for the endoplasmic reticulum stress markers IRE1α (P<0.001), ATF6 (P<0.01) and soluble BiP (P<0.001). Kyoto encyclopedia of genes and gene ontology pathway analyses of RNA sequencing experiments following HypERlnc knockdown indicate a role in cardiovascular disease states. Indeed, HypERlnc expression was significantly reduced in human cardiac tissue from heart failure patients (P<0.05, n=19) compared to controls. In addition, HypERlnc expression significantly correlated with pericyte markers in human lungs derived from patients diagnosed with idiopathic pulmonary arterial hypertension and from donor lungs (n=14).
Conclusions: Here we show that HypERlnc regulates human pericyte function and the endoplasmic reticulum stress response. In addition, RNA sequencing analyses in conjunction with reduced expression of HypERlnc in heart failure and correlation with pericyte markers in idiopathic pulmonary arterial hypertension indicate a role of HypERlnc in human cardiopulmonary disease.
- ER stress
- long non-coding RNA
- cardiovascular disease
- vascular biology
- cardiac disease
- pulmonary heart disease
- Received December 22, 2016.
- Revision received May 27, 2017.
- Accepted June 12, 2017.