Previously, we have identified ZFAS1 as a potential new long non-coding RNA (lncRNA) biomarker of acute myocardial infarction (MI) and as a sarcoplasmic reticulum Ca²⁺-ATPase 2a (SERCA2a) inhibitor, causing intracellular Ca²⁺ overload and contractile dysfunction in a mouse model of MI. In the current study, we aimed to evaluate the effects of ZFAS1 on the apoptosis of cardiomyocytes in the MI mouse model. Knockdown of endogenous ZFAS1 by virus-mediated silencing shRNA or siZFAS1 partially abrogated the ischemia-induced apoptosis of cardiomyocytes. Overexpression of ZFAS1 in normal cardiomyocytes reduced the cell viability, similar to that observed in hypoxia-treated cardiomyocytes. Moreover, ZFAS1 cardiac-specific knock-in mice showed impaired cardiac function, adversely altered Ca²⁺ homeostasis, repressed expression and activities of SERCA2a, and increased apoptosis. At the subcellular level, ZFAS1 induced mitochondrial swelling and showed a pronounced decrease in mitochondrial membrane potential. At the molecular level, ZFAS1 activated the mitochondria apoptosis pathway, which could be nearly abolished by a calcium chelator. The effects of ZFAS1 were readily reversible upon knockdown of this lncRNA. Notably, ZFAS1-FD (only functional domain) mimicked the effects of full-length ZFAS1 in regulation of cardiomyocyte apoptosis. In conclusion, our study shows that ZFAS1, an endogenous SERCA2a inhibitor, induces mitochondria-mediated apoptosis via cytosolic Ca²⁺ overload. Therefore, anti-ZFAS1 might be considered a new therapeutic strategy for protecting cardiomyocytes from MI-induced apoptosis.

Neoantigens have emerged as ideal targets for personalized cancer immunotherapy. We depict the pan-cancer peptide atlas by comprehensively collecting immunopeptidomics from 531 samples across 14 cancer and 29 normal tissues, and identify 389,165 canonical and 70,270 noncanonical peptides. We reveal that noncanonical peptides exhibit comparable presentation levels as canonical peptides across cancer types. Tumor-specific peptides exhibit significantly distinct biochemical characteristics compared with those observed in normal tissues. We further propose an immunopeptidomic-guided machine learning-based neoantigen screening pipeline (MaNeo) to prioritize neo-peptides as immunotherapy targets. Benchmark analysis reveals MaNeo results in the accurate identification of shared and tumor-specific canonical and noncanonical neo-peptides. Last, we use MaNeo to detect and validate three neo-peptides in cancer cell lines, which can effectively induce increased proliferation of active T cells and T cell responses to kill cancer cells but not damage healthy cells. The pan-cancer peptide atlas and proposed MaNeo pipeline hold great promise for the discovery of canonical and noncanonical neoantigens for cancer immunotherapies.

• The increase of ZFAS1 expression in MIRI is an important cause of cardiomyocyte apoptosis and ROS production. • ZFAS1 can directly interact with the promoter region of Notch1, recruit DNMT3b to promote DNA methylation in the promoter region of Notch1, and trigger cardiomyocyte apoptosis and ROS production after MIRI. • Nicotinamide mononucleotide has the potential to attenuate the apoptosis of cardiomyocytes after MIRI by competitively binding to DNMT3b and inhibiting the DNA methylation of Notch1.