👤 Wenfeng Shangguan

Atrial fibrosis serves as a key pathological basis for atrial fibrillation, significantly elevating the risk of cardiovascular events. However, its molecular mechanisms remain incompletely understood. N⁶-methyladenosine (m6A) modifications have been proven to involve in the pathological processes of cardiovascular diseases, yet its role in atrial fibrosis remains unclear. m6A plays an important role in disease pathogenesis via mRNA modification. This study aimed to define the role of m6A modifications in the fibrotic atria of rats with chronic intermittent hypoxia (CIH). A CIH model was established using rats living in an intermittent hypoxia simulation chamber filled with oxygen and nitrogen. Myocardial function and atrial fibrosis were examined by echocardiography, electrophysiology, and histopathology. Methylated RNA immunoprecipitation sequencing (MeRIP-Seq) and mRNA sequencing (mRNA-Seq) were performed on atria from control and CIH rats to identify differential m6A methylated genes and transcripts and further analyze their coexistence. Functional enrichment of the conjoint genes was analyzed using Gene Ontology and Kyoto Encyclopedia of Genes and Genomes assays. m6A distribution of the conjoint gene ANGPTL4 (angiopoietin like 4) was also observed. ANGPTL4 and m6A-related gene expression levels were determined by quantitative real-time polymerase chain reaction. CIH led to electrical conduction dysfunction and abnormal expression of fibrosis-associated proteins, indicating successful atrial fibrosis. Conjoint analysis identified 10 genes with upregulated m6A peaks and transcripts and 24 genes with downregulated m6A peaks and transcripts. These genes were functionally enriched in the calcium ion transport-related and fibrosis pathways (extracellular matrix receptor interaction). The m6A modification level of ANGPTL4 mRNA and the expression of four m6A regulatory enzymes were significantly different between control and CIH rats. Our results revealed that m6A modification plays a crucial role in atrial fibrosis and may provide new therapeutic strategies for this disease. Show less

To investigate the effect of tannic acid (TA) on the growth, disease resistance, and intestinal health of Chinese soft-shelled turtles, individual turtles were fed with 0 g/kg (CG), 0.5 g/kg, 1 g/kg, 2 g/kg, and 4 g/kg TA diets for 98 days. Afterwards, the turtles' disease resistance was tested using Show less

The uptake of modified lipoproteins by macrophages to form foam cells is a crucial step in atherosclerosis (AS) development. N7-methylguanosine (m7G) is frequently methylated internally in eukaryotic RNA transcripts and plays a crucial role in various processes. This study aimed to investigate the m7G RNA methylation profile in AS. We employed high-throughput sequencing to analyze the m7G methylome in foam cells induced by ox-LDL, using an in vitro AS model. Then, m7G-seq, RNA-seq, bioinformatic analysis, cell biological analyses, followed by qRT-PCR were performed. Additionally, the roles of SCARB2 and RASSF8 were investigated in an in vivo AS mouse model, and cells with SCARB2/RASSF8 overexpression/knockdown. In vitro and in vivo oil red O staining confirmed the successful establishment of the atherosclerotic foam cell and mouse models. We identified 1197 m7G peaks and 430 differentially expressed mRNAs during foam cell formation. Bioinformatics analyses revealed different m7G peaks associated with the gonadotropin-releasing hormone (GnRH) signaling pathway, cytoskeleton-dependent intracellular transport, and mitochondrial organization, regulating the processes of macrophage foaminess. Moreover, 28 key differentially expressed methylated genes were identified. m7G methyltransferases (WDR4, METTL1, WBSCR22) were upregulated in the AS cell model, and m7G modification genes (SCARB2 and RASSF8) associated with pathological processes were confirmed. Immunofluorescence staining showed that RASSF8 and SCARB2 were both expressed in AS mice plaque tissues. Finally, RASSF8/SCARB2 overexpression could promote apoptosis and lipid accumulation of ox-LDL-induced RAW264.7 cells. An m7G transcriptome-wide map of AS in vitro was created, and the differentially m7G methylated genes SCARB2 and RASSF8 may be crucial in macrophage foaminess. Our findings offer novel insights into the underlying mechanisms and potential treatments for AS. Show less

ObjectiveFibroblast growth factor receptor 1 (FGFR1) inhibitors are considered effective for treating 8p11 myeloproliferative syndrome. However, targeting FGFR1 alone may be inadequate for patients with translocated promoter region (TPR)-FGFR1 rearrangement.MethodsIn this study, we established TPR-FGFR1-expressing BaF3 cells and performed RNA sequencing analysis. Then, western blot analysis was performed to evaluate the protein expression levels of FGFR1 and phosphorylation of protein kinase B. Furthermore, flow cytometric analysis (fluorescence-activated cell sorting) was used to assess apoptosis levels.ResultsRNA sequencing analysis revealed that TPR-FGFR1-related genes are mainly involved in the epidermal growth factor receptor pathway. Gene set enrichment analysis highlighted the enrichment of genes in the phosphoinositide 3-kinase/protein kinase B pathway. FGFR1 inhibitor alone inhibited the phosphorylation of FGFR1 but not that of downstream protein kinase B. Combined FGFR1 inhibitor and protein kinase B inhibitor treatment simultaneously suppressed FGFR1 and protein kinase B phosphorylation. Fluorescence-activated cell sorting showed that combination therapy significantly increased apoptosis levels compared with FGFR1 inhibitor monotherapy.ConclusionsWe found that epidermal growth factor receptor is another activation mechanism of the protein kinase B pathway in TPR-FGFR1-expressing BaF3 cells. Furthermore, co-treatment with FGFR1 inhibitor and protein kinase B inhibitor inhibited the phosphorylation of FGFR1 and protein kinase B. Dual FGFR1 and protein kinase B inhibition enhances apoptosis, supporting dual targeting therapy for TPR-FGFR1-rearranged 8p11 myeloproliferative syndrome, offering a novel treatment direction. Show less