EPRS Regulates Proline-rich Pro-fibrotic Protein Synthesis during Cardiac Fibrosis

Abstract

Rationale: Increased protein synthesis of pro-fibrotic genes is a common feature of cardiac fibrosis, a major manifestation of heart failure. Despite this important observation, critical factors and molecular mechanisms for translational control of pro-fibrotic genes during cardiac fibrosis remain unclear.Objective: This study aimed to test the hypothesis that cardiac stress-induced expression of a bifunctional aminoacyl-tRNA synthetase (ARS), glutamyl-prolyl-tRNA synthetase (EPRS), is preferentially required for the translation of proline codon-rich (PRR) pro-fibrotic mRNAs in cardiac fibroblasts during cardiac fibrosis. Methods and Results: By analyses of multiple available unbiased large-scale screening datasets of human and mouse heart failure, we have discovered that EPRS acts as an integrated node among all the ARSs in various cardiac pathogenic processes. We confirmed that EPRS was induced at both mRNA and protein level (~1.5-2.5 fold increase) in failing hearts compared with non-failing hearts using our cohort of human and mouse heart samples. Genetic knockout of one allele of Eprs globally (Eprs +/-) using CRISPR-Cas9 technology or in a myofibroblast-specific manner (Eprs flox/+ ; Postn MCM/+ ) strongly reduces cardiac fibrosis (~50% reduction) in isoproterenol-and transverse aortic constriction-induced heart failure mouse models. Inhibition of EPRS by a prolyl-tRNA synthetase (PRS)-specific inhibitor, halofuginone (Halo), significantly decreased the translation efficiency of proline-rich collagens in cardiac fibroblasts. Furthermore, using transcriptome-wide RNA-Seq and polysome profiling-Seq in Halo-treated fibroblasts, we identified multiple novel Pro-rich genes in addition to collagens, such as Ltbp2 and Sulf1, which are translationally regulated by EPRS. As a major EPRS downstream effector, SULF1 is highly enriched in human and mouse myofibroblast. siRNA-mediated knockdown of SULF1 attenuates cardiac myofibroblast activation and collagen deposition. Conclusions:Our results indicate that EPRS preferentially controls the translational activation of proline codon-rich pro-fibrotic genes in cardiac fibroblasts and augments pathological cardiac remodeling.

Core functional nodes and sex-specific pathways in human ischaemic and dilated cardiomyopathy

“…Serum amyloid A1 (SAA1) was the most downregulated protein in both ICM and DCM (see below). Osteoglycin (OGN), important in the extracellular matrix and contributing to collagen deposition and fibrillogenesis in the heart 22,23 , and pro-fibrotic proline-rich protein 12 (PRR12) 24 , were significantly upregulated in both ICM and DCM. Periostin (POST), associated with mesenchymal differentiation in the heart 25 , was also significantly upregulated in both ICM and DCM.…”

Targeting cardiac fibrosis in heart failure with preserved ejection fraction: mirage or miracle?

“…The mechanism underlying this effect is not yet clear, but there is evidence that IL11 stimulates downstream targets of ERK which activate translation, including 40S ribosomal protein S6 kinase and eukaryotic translation initiation factor 4E (Schafer et al, 2017). Glutamyl-prolyl-tRNA synthetase, which mediates translation of proline-rich proteins such as collagen (and IL11 itself), may also play a role in the post-transcriptional control mechanism (preprint: Wu et al, 2019).…”

IL‐11 in cardiac and renal fibrosis: Late to the party but a central player

“…Interestingly, STAT3—considered the canonical signalling pathway for IL‐11—is only mildly and transiently phosphorylated after IL‐11 stimulation in primary fibroblasts, and this has little measurable transcriptional consequences. Further insights into IL‐11 signalling mechanisms have recently been elucidated by a study suggesting that IL‐11 may mediate translation of proline‐rich proteins (such as collagen or IL‐11 itself) via activation of glutamyl‐prolyl‐tRNA synthetase (EPRS) (Wu, Subbaiah, Xie, Jiang, & Mickelsen, ).…”