METHODS AND RESULTS: We investigated steady-state messenger RNA levels of 84 histone-modifying enzymes and related regulators in colony-stimulating factor-1 differentiated primary human macrophages using quantitative polymerase chain reaction. IFN-γ or IL-4 treatment for 6-48 h changed 11 mRNAs significantly. IFN-γ increased CIITA, KDM6B, and NCOA1, and IL-4 also increased KDM6B by 6 h. However, either cytokine decreased AURKB, ESCO2, SETD6, SUV39H1, and WHSC1, whereas IFN-γ alone decreased KAT2A, PRMT7, and SMYD3 mRNAs only after 18 h, which coincided with decreased cell proliferation. Rendering macrophages quiescent by growth factor starvation or adenovirus-mediated overexpression of p27(kip1) inhibited expression of AURKB, ESCO2, SUV39H1, and WHSC1, and mRNA levels were restored by overexpressing the S-phase transcription factor E2F1, implying their expression, at least partly, depended on proliferation. However, CIITA, KDM6B, NCOA1, KAT2A, PRMT7, SETD6, and SMYD3 were regulated independently of effects on proliferation. Silencing KDM6B, the only transcriptional activator upregulated by both IFN-γ and IL-4, pharmacologically or with short hairpin RNA, blunted a subset of responses to each cytokine.
CONCLUSION: These findings demonstrate that IFN-γ or IL-4 can regulate the expression of histone acetyl transferases and histone methyl transferases independently of effects on proliferation and that upregulation of the histone demethylase, KDM6B, assists phenotypic polarization by both cytokines.
METHODS: We conducted a comprehensive search across PubMed, Embase, and Web of Science until November 10 2024, selecting studies based on pre-defined criteria that involve adults with AF and measurements of VEGF levels. The selected studies included observational and experimental designs, excluding non-English and methodologically insufficient publications. Narrative synthesis was used for summarising the results.
RESULTS: Eight studies met the inclusion criteria. The studies show a general trend of elevated VEGF levels in AF patients compared to controls, with significant heterogeneity in findings across studies. VEGF subtypes such as VEGF-A and VEGF-D demonstrated stronger associations with AF risk compared to VEGF-C. These variations point to the complex role of VEGF in AF, influencing factors like angiogenesis, endothelial function, and inflammatory responses.
CONCLUSION: VEGF is potentially a significant contributor to AF pathophysiology, with its levels reflecting disease activity. The variability observed across studies suggests a need for standardized measurement approaches and further investigation into VEGF subtypes. Future research should focus on longitudinal studies to better understand the causal relationships and the potential of VEGF as a therapeutic target and biomarker in AF management.
CLINICAL TRIAL NUMBER: Not applicable.