ChGn-2 Plays a Cardioprotective Role in Heart Failure Caused by Acute Pressure Overload

Differential expression profiles and bioinformatics analysis of tRNA-derived small RNAs in epicardial fat of patients with atrial fibrillation

The exact processes underlying atrial fibrillation (AF) are still unclear. It has been suggested that epicardial adipose tissue (EAT) may contribute to arrhythmias and can release various bioactive molecules, including exosomes containing tRNA-derived small RNAs (tsRNAs). Numerous studies have indicated that these tsRNAs can significantly affect key cellular functions. However, there is currently no research investigating the relationship between tsRNAs from EAT and AF. In order to explore the regulatory mechanisms of tsRNAs from EAT associated with AF, we conducted RNA-sequencing analysis on EAT samples collected from 6 AF patients and 6 control subjects with sinus rhythm. Our analysis revealed an upregulation of 146 tsRNAs and a downregulation of 126 tsRNAs in AF. Furthermore, we randomly selected four tsRNAs (tRF-SeC-TCA-001, tiRNA-Gly-CCC-003, tRF-Gly-GCC-002, and tRF-Tyr-GTA-007) for validation using quantitative reverse transcription-polymerase chain reaction. Following this, bioinformatic analyses revealed that the target genes of these tsRNAs were prominently involved in the regulation of cell adhesion and various cellular processes mediated by plasma membrane adhesion molecules. Additionally, based on KEGG analysis, it was suggested that the majority of these target genes might contribute to the pathogenesis of AF through processes such as glycosaminoglycan biosynthesis, AMP-activated protein kinase activity, and the insulin signaling pathway. Our results elucidate changes in the expression profiles of tsRNAs within EAT samples obtained from AF patients, and they forecast potential target genes and interactions between tsRNAs and mRNA within EAT that could contribute to the pathogenesis of AF.

Fibroblasts and immune cells: at the crossroad of organ inflammation and fibrosis

The immune and fibrotic responses have evolved to work in tandem to respond to pathogen clearance and promote tissue repair. However, excessive immune and fibrotic responses lead to chronic inflammation and fibrosis, respectively, both of which are key pathological drivers of organ pathophysiology. Fibroblasts and immune cells are central to these responses, and evidence of these two cell types communicating through soluble mediators or adopting functions from each other through direct contact is constantly emerging. Here, we review complex junctions of fibroblast-immune cell cross talk, such as immune cell modulation of fibroblast physiology and fibroblast acquisition of immune cell-like functions, as well as how these systems of communication contribute to organ pathophysiology. We review the concept of antigen presentation by fibroblasts among different organs with different regenerative capacities, and then focus on the inflammation-fibrosis axis in the heart in the complex syndrome of heart failure. We discuss the need to develop anti-inflammatory and antifibrotic therapies, so far unsuccessful to date, that target novel mechanisms that sit at the crossroads of the fibrotic and immune responses.