Novel Regulators of Retina Neovascularization: A Proteomics Approach

The purpose of this study was to identify proteins that regulate vascular remodeling in an ROP mouse model. Pups were subjected to fluctuating oxygen levels and retinas sampled during vessel regression (PN12) or neovascularization (PN17) for comparative SWATH-MS proteomics using liquid chromatography-tandem mass spectrometry (LC-MS/MS). We developed a human retinal endothelial cell (HREC) ROP correlate to validate the expression of retina neovascular-specific markers. A total of 5191 proteins were identified in OIR retinas with 498 significantly regulated in elevated oxygen and 345 after a return to normoxia. A total of 122 proteins were uniquely regulated during vessel regression and 69 during neovascularization (FC ≥ 1.5; p ≤ 0.05), with several validated by western blot analyses. Expressions of 56/69 neovascular-specific proteins were confirmed in hypoxic HRECs with 23 regulated in the same direction as OIR neovascular retinas. These proteins control angiogenesis-related processes including matrix remodeling, cell migration, adhesion, and proliferation. RNAi and transfection overexpression studies confirmed that VASP and ECH1, showing the highest levels in hypoxic HRECs, promoted human umbilical vein (HUVEC) and HREC cell proliferation, while SNX1 and CD109, showing the lowest levels, inhibited their proliferation. These proteins are potential biomarkers and exploitable intervention tools for vascular-related disorders. The proteomics data set generated has been deposited to the ProteomeXchange/iProX Consortium with the Identifier:PXD029208.

Enoyl coenzyme A hydratase 1 alleviates nonalcoholic steatohepatitis in mice by suppressing hepatic ferroptosis

Nonalcoholic steatohepatitis (NASH) is a common metabolic disorder that is a major contributor to health care expenditures worldwide. Enoyl coenzyme A hydratase 1 (ECH1) is initially recognized as a key component in mitochondrial fatty acid β-oxidation, and subsequent studies have demonstrated that it regulates multiple pathophysiological processes. However, the relationship between ECH1 and NASH has remained largely unknown. Herein, we investigated the role of ECH1 in NASH progression. Adeno-associated virus-mediated genetic engineering was used to investigate the role of ECH1. Alterations in hepatic steatosis, inflammation, fibrogenesis, oxidative stress, apoptosis, and liver injury were monitored using liver or serum samples from mice. ECH1 expression was significantly higher in human NASH biopsy specimens and in methionine choline-deficient (MCD) diet-fed mice. ECH1 overexpression significantly alleviated hepatic steatosis, inflammation, fibrogenesis, apoptosis, and oxidative stress in livers of mice. In addition, ECH1 overexpression also reduced alanine aminotransferase and proinflammatory cytokine levels in serum and triglyceride levels in livers. Consistently, ECH1 knockdown suppressed this beneficial phenotype. Mechanistically, ECH1-knockdown mice treated with ferrostatin-1 (Fer-1) showed an alleviated NASH phenotype compared with the untreated knockdown mice. Meanwhile, we detected changes in Erk signaling pathway when ECH1 was overexpressed or knocked down, which may partially explain the potential mechanism of ECH1 regulation of ferroptosis.In summary, ECH1 may ameliorate steatohepatitis by inhibiting ferroptosis. Pharmacological or genetic ECH1 activation may have potential as a future therapy for NASH.NEW & NOTEWORTHY Enoyl coenzyme A hydratase 1 (ECH1) is a key component in mitochondrial fatty acid β-oxidation and is also a well-known enzyme for lipid metabolism. However, the biological role of ECH1 in the development of NASH is still unclear. Herein, we demonstrated that ECH1 inhibits NASH by inhibiting ferroptosis, thus providing a novel target for therapeutic intervention for future treatment of NASH.

Identification of autoantibodies to ECH1 and HNRNPA2B1 as potential biomarkers in the early detection of lung cancer

Identification of biomarkers for early detection of lung cancer (LC) is important, in turn leading to more effective treatment and reduction of mortality. Serological proteome analysis (SERPA) was used to identify proteins around 34 kD as ECH1 and HNRNPA2B1, which had been recognized by serum autoantibody from 25 LC patients. In the validation study, including 90 sera from LC patients and 89 sera from normal individuals, autoantibody to ECH1 achieved an area under the curve (AUC) of 0.799 with sensitivity of 62.2% and specificity of 95.5% in discriminating LC from normal individuals, and showed negative correlation with tumor size (r_s = -0.256, p = 0.023). Autoantibody to HNRNPA2B1 performed an AUC of 0.874 with sensitivity of 72.2% and specificity of 95.5%, and showed negative correlation with lymph node metastasis (r_s = -0.279, p = 0.012). By using longitudinal preclinical samples, autoantibody to ECH1 showed an AUC of 0.763 with sensitivity of 60.0% and specificity of 89.3% in distinguishing early stage LC from matched normal controls, and elevated autoantibody levels could be detected greater than 2 y before LC diagnosis. ECH1 and HNRNPA2B1 are autoantigens that elicit autoimmune responses in LC and their autoantibody can be the potential biomarkers for the early detection of LC.