The TRIM21-FOXD1-BCL-2 axis underlies hyperglycaemic cell death and diabetic tissue damage

TRIM21 knockout alleviates renal fibrosis by promoting autophagic degradation of mature TGF-β1

Renal fibrosis is a common feature of chronic kidney disease, in which transforming growth factor-β1 (TGF-β1) plays an important role. Tripartite motif-containing 21 (TRIM21), an E3 ubiquitin ligase, has been studied for its role in acute kidney injury, but its role in renal fibrosis has not been reported. We analyzed public RNA-seq data of unilateral ureteral obstruction (UUO), ischemia-reperfusion injury (I/R), and aristolochic acid (AA)-induced renal fibrosis and found that TRIM21 expression was significantly elevated in fibrotic kidneys, which was verified by Western blot results corresponding to the mouse models. Similarly, TRIM21 expression was significantly elevated and negatively correlated with renal function in human fibrotic kidneys. We showed that TRIM21 knockout alleviated renal fibrosis in UUO mice. In vitro, TRIM21 knockout reduced TGF-β1-induced expression of mature TGF-β1 in HK-2 cells and primary renal tubular cells (PTECs), and this process was reversed by the autophagy inhibitor bafilomycin A1 (Baf-A1). Specifically, TRIM21 promoted K63-linked ubiquitination of p62, inhibited its oligomerization and thus its aggregation and segregation functions, and suppressed autophagic degradation of TGF-β1. Meanwhile, in the UUO mouse model, TRIM21 knockout promoted autophagy levels, and reduced the protein levels of mature TGF-β1 and the phosphorylation levels of SMAD2/3. In conclusion, our study demonstrates that TRIM21 knockdown alleviates renal fibrosis by promoting autophagic degradation of mature TGF-β1 and provides an insight into TRIM21 as a potential therapeutic target for the treatment of kidney fibrosis.

Screening and identification of key biomarkers associated with endometriosis using bioinformatics and next-generation sequencing data analysis

Background

Endometriosis is a common cause of endometrial-type mucosa outside the uterine cavity with symptoms such as painful periods, chronic pelvic pain, pain with intercourse and infertility. However, the early diagnosis of endometriosis is still restricted. The purpose of this investigation is to identify and validate the key biomarkers of endometriosis.

Methods

Next-generation sequencing dataset GSE243039 was obtained from the Gene Expression Omnibus database, and differentially expressed genes (DEGs) between endometriosis and normal control samples were identified. After screening of DEGs, gene ontology (GO) and REACTOME pathway enrichment analyses were performed. Furthermore, a protein–protein interaction (PPI) network was constructed and modules were analyzed using the Human Integrated Protein–Protein Interaction rEference database and Cytoscape software, and hub genes were identified. Subsequently, a network between miRNAs and hub genes, and network between TFs and hub genes were constructed using the miRNet and NetworkAnalyst tool, and possible key miRNAs and TFs were predicted. Finally, receiver operating characteristic curve analysis was used to validate the hub genes.

Results

A total of 958 DEGs, including 479 upregulated genes and 479 downregulated genes, were screened between endometriosis and normal control samples. GO and REACTOME pathway enrichment analyses of the 958 DEGs showed that they were mainly involved in multicellular organismal process, developmental process, signaling by GPCR and muscle contraction. Further analysis of the PPI network and modules identified 10 hub genes, including vcam1, snca, prkcb, adrb2, foxq1, mdfi, actbl2, prkd1, dapk1 and actc1. Possible target miRNAs, including hsa-mir-3143 and hsa-mir-2110, and target TFs, including tcf3 (transcription factor 3) and clock (clock circadian regulator), were predicted by constructing a miRNA-hub gene regulatory network and TF-hub gene regulatory network.

Conclusions

This investigation used bioinformatics techniques to explore the potential and novel biomarkers. These biomarkers might provide new ideas and methods for the early diagnosis, treatment and monitoring of endometriosis.

Degradation meets development: Implications in β-cell development and diabetes

Pancreatic development is orchestrated by timely synthesis and degradation of stage-specific transcription factors (TFs). The transition from one stage to another stage is dependent on the precise expression of the developmentally relevant TFs. Persistent expression of particular TF would impede the exit from the progenitor stage to the matured cell type. Intracellular protein degradation-mediated protein turnover contributes to a major extent to the turnover of these TFs and thereby dictates the development of different tissues. Since even subtle changes in the crucial cellular pathways would dramatically impact pancreatic β-cell performance, it is generally acknowledged that the biological activity of these pathways is tightly regulated by protein synthesis and degradation process. Intracellular protein degradation is executed majorly by the ubiquitin proteasome system (UPS) and Lysosomal degradation pathway. As more than 90% of the TFs are targeted to proteasomal degradation, this review aims to examine the crucial role of UPS in normal pancreatic β-cell development and how dysfunction of these pathways manifests in metabolic syndromes such as diabetes. Such understanding would facilitate designing a faithful approach to obtain a therapeutic quality of β-cells from stem cells.