MiR-337-3p improves metabolic-associated fatty liver disease through regulation of glycolipid metabolism

MicroRNAs in the Diagnosis of Digestive Diseases: A Comprehensive Review

MicroRNAs (miRNAs) have emerged as crucial regulators in digestive pathologies, including inflammatory bowel disease (miR-31, miR-155, and miR-21), colorectal cancer (miR-21, miR-598, and miR-494), and non-alcoholic fatty liver disease (miR-21, miR-192, and miR-122). Their capacity to modulate gene expression at the post-transcriptional level makes them highly promising candidates for biomarkers and therapeutic interventions. However, despite considerable progress, their clinical application remains challenging. Research has shown that miRNA expression is highly dynamic, varying across patients, disease stages, and different intestinal regions. Their dual function as both oncogenes and tumor suppressors further complicates their therapeutic use, as targeting miRNAs may yield unpredictable effects. Additionally, while miRNA-based therapies hold great potential, significant hurdles persist, including off-target effects, immune activation, and inefficiencies in delivery methods. The intricate interplay between miRNAs and gut microbiota adds another layer of complexity, influencing disease mechanisms and treatment responses. This review examined the role of miRNAs in digestive pathologies, emphasizing their diagnostic and therapeutic potential. While they offer new avenues for disease management, unresolved challenges underscore the need for further research to refine their clinical application.

miRNAs in umbilical Wharton's jelly in neonates with different birth weights: A pilot study

BACKGROUND

Birth weight is a critical indicator of perinatal health. miRNAs are small non-coding RNA molecules, ranging from 18 to 25 nucleotides in length, that regulate gene expression. Specific miRNAs have been implicated in metabolic pathways influencing fetal growth, and their dysregulation may contribute to variations in birth weight. Our objective was to isolate amplifiable miRNAs from umbilical cord tissue and compare their expression across three patient groups.

METHODS

The study sample comprised 23 patients: 8 small for gestational age (SGA), 10 large for gestational age (LGA), and 5 appropriate for gestational age (AGA). Umbilical cord tissue samples were collected immediately after childbirth, stored, and subsequently processed. The miRNA expression profile of these samples was analyzed using high-throughput sequencing, and the results were evaluated through bioinformatic analysis.

RESULTS

We identified significant differences in the expression levels of 6 miRNAs. miR-324-3p was downregulated in SGA compared to both AGA and LGA groups. Conversely, miR-337-3p was upregulated in LGA compared to both SGA and AGA. miR-760 was downregulated in LGA relative to SGA and AGA, while miR-4707-3p, miR-548a-3p, and miR-6733-5p were upregulated in both SGA and LGA compared to AGA. Most of these miRNAs appear to be associated with the transforming growth factor-beta signaling pathway.

CONCLUSIONS

This exploratory study suggests that miRNA expression in umbilical cord tissue is associated with birth weight. Notably, the downregulation of miR-324-3p in SGA newborns indicates that its decreased expression may be related to SGA conditions.

Excessive fatty acids activate PRMT5/MDM2/Drosha pathway to regulate miRNA biogenesis and lipid metabolism

BACKGROUND

Excessive fatty acids in the liver lead to the accumulation of lipotoxic lipids and then cellular stress to further evoke the related disease, like non-alcoholic fatty liver disease (NAFLD). As reported, fatty acid stimulation can cause some specific miRNA dysregulation, which caused us to investigate the relationship between miRNA biogenesis and fatty acid overload.

METHODS

Gene expression omnibus (GEO) dataset analysis, miRNA-seq, miRNA cleavage assay, RT-qPCR, western blotting, immunofluorescence and co-immunoprecipitation (co-IP) were used to reveal the change of miRNAs under pathological status and explore the relevant mechanism. High fat, high fructose, high cholesterol (HFHFrHC) diet-fed mice transfected with AAV2/8-shDrosha or AAV2/8-shPRMT5 were established to investigate the in vivo effects of Drosha or PRMT5 on NAFLD phenotype.

RESULTS

We discovered that the cleavage of miRNAs was inhibited by analysing miRNA contents and detecting some representative pri-miRNAs in multiple mouse and cell models, which was further verified by the reduction of the Microprocessor activity in the presence of palmitic acid (PA). In vitro, PA could induce Drosha, the core RNase III in the Microprocessor complex, degrading through the proteasome-mediated pathway, while in vivo, knockdown of Drosha significantly promoted NAFLD to develop to a more serious stage. Mechanistically, our results demonstrated that PA can increase the methyltransferase activity of PRMT5 to degrade Drosha through MDM2, a ubiquitin E3 ligase for Drosha. The above results indicated that PRMT5 may be a critical regulator in lipid metabolism during NAFLD, which was confirmed by the knocking down of PRMT5 improved aberrant lipid metabolism in vitro and in vivo.

CONCLUSIONS

We first demonstrated the relationship between miRNA dosage and NAFLD and proved that PA can activate the PRMT5-MDM2-Drosha signalling pathway to regulate miRNA biogenesis.