USP13 reduces septic mediated cardiomyocyte oxidative stress and inflammation by inducing Nrf2

Ubiquitin-specific protease 13 regulates FcεRI-mediated mast cell activation and allergic inflammation via SYK protein modulation

Mast cells (MCs) are therapeutic targets for high-affinity IgE Fc receptors (FcεRI)-mediated allergic responses. Deubiquitinating enzymes (DUBs), including ubiquitin-specific protease 13 (USP13), are involved in multiple inflammatory processes. This study aims to reveal USP13's role in FcεRI-mediated MC activation and its underlying mechanisms. Our results showed USP10/13 inhibitor spautin-1 inhibited IgE-mediated MC activation, as evidenced by a reduction in the release of β-hexosaminidase (β-hex) and histamine and decreased expression and secretion of inflammatory cytokines. Spautin-1 also attenuated inflammatory processes in IgE-mediated passive cutaneous anaphylaxis (PCA) and ovalbumin (OVA)-induced active systemic anaphylaxis (ASA) models. Furthermore, knockdown of USP13 by short hairpin (sh)RNA diminished IgE-induced MC activation. Protein-protein interactions assays showed that USP13 interacted with the co-immunoprecipitated protein spleen tyrosine kinase (SYK) and deubiquitinated SYK. USP13 bound the kinase domain of SYK and removed its K63-linked polyubiquitination chain, yielding a more stable SYK protein. Importantly, 2-methoxyestradiol (2-Meth) was identified as a potential inhibitor of USP13 and inhibited FcεRI-mediated MC activation effectively in vitro and in vivo. In conclusion, it elucidated the molecular mechanism by which USP13 regulated SYK stability in MCs. The USP13-SYK axis may serve as a therapeutic target for treating FcεRI-mediated activation of MCs and associated inflammatory responses.

USP13 overexpression in BMSCs enhances anti-apoptotic ability and guards against methylprednisolone-induced osteonecrosis in rats

Methylprednisolone (MPS) use is linked to increased cases of osteonecrosis of the femoral head (ONFH). Bone marrow mesenchymal stem cells (BMSCs) have shown potential for treating MPS-induced ONFH, but their effectiveness is limited by high apoptosis rates post-transplantation. We developed a pretreatment strategy for BMSCs to improve their viability. In a rat model of MPS-induced ONFH, we evaluated the effects of USP13 overexpression in BMSCs through micro-CT, HE staining, and TUNEL staining. USP13-overexpressing BMSCs significantly reduced ONFH severity compared to plain BMSCs and direct lentivirus injection. USP13 also protected BMSCs from MPS-induced apoptosis by modulating PTEN and reducing AKT phosphorylation. This led to decreased expression of apoptotic genes and proteins in USP13-overexpressing BMSCs. Our findings highlight USP13 as a promising target for enhancing BMSC survival and efficacy in treating MPS-induced ONFH.

miR-361-3p overexpression promotes apoptosis and inflammation by regulating the USP49/IκBα/NF-κB pathway to aggravate sepsis-induced myocardial injury

Background

Sepsis is a major cause of in-hospital death, particularly in the intensive care unit. A huge amount of effort has been put into identifying reliable biomarkers to improve the prognosis of patients with sepsis. Among the numerous candidates, microRNAs have attracted attention because of their promising prognostic value. Multiple miRNAs have been suggested to play vital roles in manipulating the nuclear factor-kappa B (NF-κB) pathway, a key factor involved in sepsis. In this study, we attempted to elucidate the potential functions of miR-361-3p in sepsis-induced myocardial injury in vivo and in vitro.

Methods

A sepsis model was established by cecal ligation and puncture (CLP) in rats and by lipopolysaccharide (LPS) in H9c2 cells. The functions of miR-361-3p were revealed by assessing the level of biomarkers of myocardial injury and inflammation by Enzyme-linked immunosorbent assay, as well as the apoptosis by terminal deoxynucleotidyl transferase dUTP nick-end labeling staining and flow cytometry. Binding of miR-361-3p and the 3' untranslated region of ubiquitin-specific peptidase 49 (Usp49) was revealed by Dual luciferase reporter gene assay. The interaction of USP49 and its downstream target NF-κB inhibitor alpha (IκBα) was revealed by Co-immunoprecipitation and western blot analysis.

Results

miR-361-3p antagomir inhibited myocardial injury and inflammation in CLP-induced rats, as evidenced by a decrease in the serum levels of cardiac troponin I, creatine kinase-MB, interleukin-1 beta (IL-1β), IL-6, and tumor necrosis factor-alpha and cell apoptosis. However, miR-361-3p agomir aggravated sepsis-induced myocardial injury. Moreover, miR-361-3p inhibition induced the inhibition of LPS-induced apoptosis and inflammation in H9c2 cells. miR-361-3p could inhibit the expression of Usp49 by binding to its 3' untranslated region. Furthermore, we demonstrated that Usp49 binds to IκBα and mediates its deubiquitination, leading to the stabilization of IκBα, which results in the cytoplasmic accumulation of NF-κB and eventually the suppression of NF-κB activity.

Conclusion

Taken together, our data demonstrate that miR-361-3p overexpression promotes apoptosis and inflammation by regulating the USP49/IκBα/NF-κB pathway to aggravate sepsis-induced myocardial injury.

USP13 regulates ferroptosis in chicken follicle granulosa cells by deubiquitinating ATG7

The development and maturation of follicles are intricately linked to egg production and reproductive performance of chickens. Granulosa cells death directly affects the development and maturation of follicles, thereby impacting the reproductive performance of hens. Ferroptosis is a new type of cell death, it is unknown how it affects the growth and development of chicken follicles. In this study, RNA-seq analysis revealed significant differences in the expression of ferroptosis-related genes between normal follicles and atretic follicles, suggesting a potential role for ferroptosis in follicle growth and development. In addition, we found that ubiquitin-specific protease 13 (USP13) was significantly upregulated in atrophic follicles. Overexpression of USP13 results in depletion of glutathione (GSH), peroxidation of lipids, accumulation of iron, and activation of ferroptosis in chicken granulosa cells. In contrast, USP13 knockdown significantly inhibited ferroptosis events. Mechanistically, USP13 prevents the degradation of autophagy related 7 (ATG7) by deubiquitinating it, thereby enhancing the stability of ATG7 protein and ultimately promoting ferroptosis. In conclusion, this study elucidates the crucial role of the USP13-ATG7 axis in regulating ferroptosis in chicken follicle granulosa cells, thereby presenting a novel avenue for molecular breeding research in chickens.

LncRNA FRMD6-AS1/miR-491-5p/USP13 pathway attenuated ferroptosis and contributed to liver fibrosis

Liver fibrosis is an invertible pathophysiologic process featured by excessive accumulation of extracellular matrix (ECM) which injures liver cells and activates hepatic stellate cells (HSCs). Besides, inducing ferroptosis in activated HSCs can alleviate liver fibrosis. LncRNAs modulate ferroptosis in activated HSCs and ECM deposition in liver fibrosis. However, the role of lncRNA FRMD6-AS1 in liver fibrosis is not discovered. In this study, lncRNA FRMD6-AS1 was dramatically up-regulated in activated HSCs. Knockdown of FRMD6-AS1 markedly increased iron ion, ROS and MDA levels, decreased GSH level, SLC7A11 and GPX4 protein expressions in activated HSCs. In addition, HSCs activation markers α-SMA and COL1α1 expressions were up-regulated in activated HSCs; knockdown of FRMD6-AS1 markedly down-regulated α-SMA and COL1α1 expressions in HSCs. Besides, lncRNA FRMD6-AS1 could interact with miR-491-5p, and negatively modulate miR-491-5p expression. USP13 was a target of miR-491-5p, and could be negatively modulated by miR-491-5p. Moreover, FRMD6-AS1 knockdown increased iron ion and ROS levels, decreased SLC7A11 and GPX4 protein expressions, facilitated HSCs viability, and up-regulated α-SMA and COL1α1 expressions via miR-491-5p/USP13 pathway. Finally, FRMD6-AS1 knockdown restored liver tissue structure and abrogated fibrosis in livers in a CCL4 liver fibrosis mouse model. Hence, lncRNA FRMD6-AS1/miR-491-5p/USP13 pathway repressed ferroptosis, promoted ECM deposition and facilitated liver fibrosis in vitro and in vivo models.