Diagnostic and therapeutic potential of RNASET2 in Crohn's disease: Disease-risk polymorphism modulates allelic-imbalance in expression and circulating protein levels and recombinant-RNASET2 attenuates pro-inflammatory cytokine secretion

A broken network of susceptibility genes in the monocytes of Crohn's disease patients

Genome-wide association studies have identified over 200 genetic loci associated with inflammatory bowel disease; however, the mechanism of such a large amount of susceptibility genes remains uncertain. In this study, we integrated bioinformatics analysis and two independent single-cell transcriptome datasets to investigate the expression network of 232 susceptibility genes in Crohn's disease (CD) patients and healthy controls. The study revealed that most of the susceptibility genes are specifically and strictly expressed in the monocytes of the human intestinal tract. The susceptibility genes established a network within the monocytes of health control. The robustness of a gene network may prevent disease onset that is influenced by the genetic and environmental alteration in the expression of susceptibility genes. In contrast, we showed a sparse network in pediatric/adult CD patients, suggesting the broken network contributed to the CD etiology. The network status of susceptibility genes at the single-cell level of monocytes provided novel insight into the etiology.

Transcriptome-wide association studies associated with Crohn's disease: challenges and perspectives

Crohn's disease (CD) is regarded as a lifelong progressive disease affecting all segments of the intestinal tract and multiple organs. Based on genome-wide association studies (GWAS) and gene expression data, transcriptome-wide association studies (TWAS) can help identify susceptibility genes associated with pathogenesis and disease behavior. In this review, we overview seven reported TWASs of CD, summarize their study designs, and discuss the key methods and steps used in TWAS, which affect the prioritization of susceptibility genes. This article summarized the screening of tissue-specific susceptibility genes for CD, and discussed the reported potential pathological mechanisms of overlapping susceptibility genes related to CD in a certain tissue type. We observed that ileal lipid-related metabolism and colonic extracellular vesicles may be involved in the pathogenesis of CD by performing GO pathway enrichment analysis for susceptibility genes. We further pointed the low reproducibility of TWAS associated with CD and discussed the reasons for these issues, strategies for solving them. In the future, more TWAS are needed to be designed into large-scale, unified cohorts, unified analysis pipelines, and fully classified databases of expression trait loci.

Musashi-2 binds with Fbxo6 to induce Rnaset2 ubiquitination and chemokine signaling pathway during vascular smooth muscle cell phenotypic switch in atherosclerosis

OBJECTIVE

The objective of this study is to determine how Musashi-2 (MSI2) affects vascular smooth muscle cell (VSMC) phenotypic switch and contributes to atherosclerosis (AS).

METHODS

Primary mouse VSMCs were transfected with MSI2 specific siRNA and treated with platelet-derived growth factor-BB (PDGF-BB). The proliferation, cell-cycle, and migration of VSMCs were determined by CCK-8, flow cytometry, wound healing, and transwell assays. Western blot and qRT-PCR were conducted to analyze the protein and mRNA expression. Moreover, the correlation between MSI2, Fbxo6, Rnaset2, and chemokine signaling was predicted and verified using RNAct database, KEGG, wiki, RNA-binding protein immunoprecipitation and co-immunoprecipitation. Moreover, H&E and Oil Red O staining were employed for assessing necrotic core and lipid accumulation in AS mouse aorta tissues. The numbers of B lymphocytes and monocytes, and the levels of triglyceride (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDLC), and low-density lipoprotein cholesterol (LDL-C) in AS mice blood were investigated using flow cytometry and corresponding commercial kits, respectively.

RESULTS

MSI2 was up-regulated in the PDGF-BB-treated VSMCs. Knockdown of MSI2 inhibited VSMC proliferation, cell-cycle, and migration. Moreover, MSI2 regulated VSMC phenotypic switch through binding with Fbxo6 to induce Rnaset2 ubiquitination. MSI2 knockdown inhibited chemokine signaling via regulating Fbxo6/Rnaset2 axis. In AS mice, knockdown of MSI2 inhibited the formation of necrotic core and atherosclerotic plaque, and inhibited chemokine signaling via regulating Fbxo6/Rnaset2 axis.

CONCLUSION

Our findings demonstrated that MSI2 could bind with Fbxo6 to induce Rnaset2 ubiquitination and the activation of chemokine signaling pathway during VSMC phenotypic switch in AS.