Myocardial infarction drives trained immunity of monocytes, accelerating atherosclerosis.

BACKGROUND AND AIMS: Survivors of acute coronary syndromes face an elevated risk of recurrent atherosclerosis-related vascular events despite advanced medical treatments. The underlying causes remain unclear. This study aims to investigate whether myocardial infarction (MI)-induced trained immunity in monocytes could sustain proatherogenic traits and expedite atherosclerosis. METHODS: Apolipoprotein-E deficient (ApoE-/-) mice and adoptive bone marrow transfer chimeric mice underwent MI or myocardial ischaemia-reperfusion (IR). A subsequent 12-week high-fat diet (HFD) regimen was implemented to elucidate the mechanism behind monocyte trained immunity. In addition, classical monocytes were analysed by flow cytometry in the blood of enrolled patients. RESULTS: In MI and IR mice, blood monocytes and bone marrow-derived macrophages exhibited elevated spleen tyrosine kinase (SYK), lysine methyltransferase 5A (KMT5A), and CCHC-type zinc finger nucleic acid-binding protein (CNBP) expression upon exposure to a HFD or oxidized LDL (oxLDL) stimulation. MI-induced trained immunity was transmissible by transplantation of bone marrow to accelerate atherosclerosis in naive recipients. KMT5A specifically recruited monomethylation of Lys20 of histone H4 (H4K20me) to the gene body of SYK and synergistically transactivated SYK with CNBP. In vivo small interfering RNA (siRNA) inhibition of KMT5A or CNBP potentially slowed post-MI atherosclerosis. Sympathetic denervation with 6-hydroxydopamine reduced atherosclerosis and inflammation after MI. Classical monocytes from ST-elevation MI (STEMI) patients with advanced coronary lesions expressed higher SYK and KMT5A gene levels. CONCLUSIONS: The findings underscore the crucial role of monocyte trained immunity in accelerated atherosclerosis after MI, implying that SYK in blood classical monocytes may serve as a predictive factor for the progression of atherosclerosis in STEMI patients.

NLRC5, a valuable marker for the diagnosis and prognostic assessment of hepatocellular carcinoma.

BACKGROUND: NLR family CARD domain containing 5 (NLRC5) is involved the initiation and progression of several cancers. However, its role in hepatocellular carcinoma (HCC) is still unclear. This study aimed to explore the expression, clinical significance, and regulated gene sets of NLRC5 in HCC. METHODS: Data related to NLRC5 was extracted from The Cancer Genome Atlas (TCGA) database and analyzed. Quantitative real-time polymerase chain reaction (qRT-PCR) was conducted to verify the NLRC5 mRNA expression in HCC. Immunohistochemistry (IHC) and western blot were performed to detect the NLRC5 protein level in HCC. The clinical significance of NLRC5 was investigated after separating patients into NLRC5-positive and NLRC5-negative groups based on the IHC results. Gene set enrichment analysis (GSEA) was performed to detect gene sets regulated by NLRC5 in HCC. RESULTS: Increased NLRC5 mRNA and protein expression were found in HCC tissues compared to paracancerous tissues. Moreover, enhanced NLRC5 protein expression was associated with a higher presence rate of cirrhosis, a higher TNM stage, and a shorter 3-year overall survival (OS) of HCC participants. Finally, gene sets related to cancer metastasis were up-regulated in the NLRC5 high phenotype. CONCLUSIONS: NLRC5 is a potential marker for the diagnosis and prognostic assessment of HCC.