Recent advances in methylation modifications of microRNA

Serine Hydroxymethyltransferase Modulates Midgut Physiology in Aedes aegypti Through miRNA Regulation: Insights from Small RNA Sequencing and Gene Expression Analysis

Aedes aegypti mosquitoes are critical vectors of arboviruses, responsible for transmitting pathogens that pose significant public health challenges. Serine hydroxymethyltransferase (SHMT), a key enzyme in one-carbon metabolism, plays a vital role in various biological processes, including DNA synthesis, energy metabolism, and cell proliferation. Although SHMT is expressed at low levels in the midgut of Aedes aegypti, its silencing has been shown to inhibit blood meal digestion. The precise mechanisms by which SHMT regulates midgut physiology in mosquitoes remain poorly understood. In this study, we employed small RNA sequencing and quantitative PCR to identify differentially expressed miRNAs (DEMs) following SHMT downregulation. We focused on a subset of DEMs-miR-2940-5p, miR-2940-3p, miR-2941, and miR-306-5p-to explore their potential biological functions. To further elucidate the molecular mechanisms underlying the miRNA response to SHMT downregulation, we analyzed the expression levels of key genes involved in the miRNA biogenesis pathway. Our results demonstrated that several critical enzymes, including Drosha, Dicer1, and AGO1, exhibited significant changes in expression upon SHMT silencing. This study provides new insights into the molecular mechanisms through which SHMT influences the biological functions and nutritional metabolism of the mosquito midgut. By linking SHMT activity to miRNA regulation, our findings highlight a potential pathway by which SHMT modulates midgut physiology, offering a foundation for future research into mosquito biology and vector control strategies.

The roles of LncRNA CARMN in cancers: biomarker potential, therapeutic targeting, and immune response

Long non-coding RNAs (LncRNAs) are crucial regulators of gene expression and cellular processes, with significant implications for cancer research. This review focuses on the role of LncRNA CARMN (Cardiac Arrest and Regulated Myocyte Nuclear Protein) in various cancers. CARMN, originally identified for its function in cardiac tissues, has shown dysregulated expression in several tumor types, including cervical, breast, colorectal, and esophageal cancers. Its altered expression often correlates with tumor progression, metastasis, and patient prognosis, suggesting its potential as both a biomarker and therapeutic target. In cervical cancer, CARMN's role as a tumor suppressor is highlighted by its ability to inhibit cell proliferation, migration, and invasion through interaction with the miR-92a-3p/BTG2 axis and modulation of the Wnt/β-catenin signaling pathway. In breast cancer, CARMN acts as an enhancer RNA, affecting epithelial-mesenchymal transition and metastasis by regulating MMP2 via DHX9. The downregulation of CARMN in triple-negative breast cancer is associated with enhanced sensitivity to chemotherapy. In colorectal cancer, CARMN's expression is regulated by m6A methylation and mutant p53, influencing tumor growth through miR-5683 and FGF2. Lastly, in esophageal cancer, genetic variations in CARMN affect cancer susceptibility, with certain SNPs and haplotypes associated with either increased or decreased risk. Additionally, the relationship between CARMN and immune cell dynamics highlights its potential role in cancer immune surveillance and therapy. Finally, we found that CARMN may regulate immune cell exhaustion in the tumor microenvironment by influencing the recruitment and activation of NK cells and T cells, as well as modulating macrophage polarization. This review emphasizes the diverse roles of CARMN across different cancers and its potential as a diagnostic and therapeutic tool. Future research should address the mechanistic details of CARMN's involvement in cancer, validate its clinical utility, and explore its therapeutic potential in combination with existing treatments.

Emerging Orchestrator of Ecological Adaptation: m6A Regulation of Post-Transcriptional Mechanisms

Genetic mechanisms have been at the forefront of our exploration into the substrate of adaptive evolution and phenotypic diversification. However, genetic variation only accounts for a fraction of phenotypic variation. In the last decade, the significance of RNA modification mechanisms has become more apparent in the context of organismal adaptation to rapidly changing environments. RNA m6A methylation, the most abundant form of RNA modification, is emerging as a potentially significant player in various biological processes. Despite its fundamental function to regulate other major post-transcriptional mechanisms such as microRNA and alternative splicing, its role in ecology and evolution has been understudied. This review highlights the potential importance of m6A RNA methylation in ecological adaptation, emphasising the need for further research, especially in natural systems. We focus on how m6A not only affects mRNA fate but also influences miRNA-mediated gene regulation and alternative splicing, potentially contributing to organismal adaptation. The aim of this review is to synthesise key background information to enhance our understanding of m6A mechanisms driving species survival in dynamic environments and motivate future research into the dynamics of adaptive RNA methylation.