Ubiquitin-Specific Protease 22 Promotes Neural Stem Cells Stemness Maintenance and Adult Hippocampal Neurogenesis, Contributing to Cognitive Recovery Following Traumatic Brain Injury

USP22 enhances atherosclerotic plaque stability and macrophage efferocytosis by stabilizing PPARγ

Atherosclerosis is a chronic inflammatory disease that strongly threatens human health, and macrophages play a pivotal role in its pathogenesis. Ubiquitin-specific peptidase 22 (USP22) is involved in the regulation of macrophage inflammation. However, its role in the atherosclerotic microenvironment remains unclear. In this study, we found that USP22 overexpression in macrophages alleviated atherosclerosis progression in ApoE-/- mice. In vitro, USP22 silencing enhanced macrophage inflammation and foam cell formation, and macrophage efferocytosis was significantly impaired. Mechanistically, USP22 bound to peroxisome proliferator-activated receptor γ (PPARγ) and inhibited its ubiquitination, thereby stabilizing PPARγ and promoting efferocytosis. In addition, intraperitoneal injection of the USP22 inhibitor USP22i-S02 exacerbated atherosclerosis in ApoE-/- mice. In summary, these findings indicate that USP22 may be a potential therapeutic target for the treatment of atherosclerosis.

USP22 promotes gefitinib resistance and inhibits ferroptosis in non-small cell lung cancer by deubiquitination of MDM2

BACKGROUND

The emergence of chemoresistance markedly compromised the treatment efficiency of human cancer, including non-small cell lung cancer (NSCLC). In the present study, we aimed to explore the effects of ubiquitin-specific peptidase 22 (USP22) and murine double minute 2 (MDM2) in gefitinib resistance in NSCLC.

METHODS

Immunohistochemistry (IHC) assay, quantitative real-time polymerase chain reaction (qRT-PCR) assay and western blot assay were carried out to determine the expression of USP22 and MDM2. Transwell assay and flow cytometry analysis were performed to evaluate cell migration and apoptosis. Cell Counting Kit-8 (CCK-8) assay was employed to assess gefitinib resistance. The phenomenon of ferroptosis was estimated by related commercial kits. The oxidized C11-BODIPY fluorescence intensity by C11-BODIPY staining. The relation between USP22 and MDM2 was analyzed by ubiquitination assay and co-immunoprecipitation (Co-IP) assay.

RESULTS

USP22 was abnormally upregulated in NSCLC tissues and cells, and USP22 silencing markedly repressed NSCLC cell migration and facilitated apoptosis and ferroptosis. Moreover, our results indicated that ferroptosis could enhance the suppressive effect of gefitinib on NSCLC cells. Besides, USP22 overexpression enhanced gefitinib resistance and ferroptosis protection in NSCLC cells. Mechanically, USP22 stabilized MDM2 and regulated MDM2 expression through deubiquitination of MDM2. MDM2 deficiency partially restored the effects of USP22 on gefitinib resistance and ferroptosis in NSCLC cells. Of note, we validated the promotional effect of USP22 on gefitinib resistance in NSCLC in vivo through establishing the murine xenograft model.

CONCLUSION

USP22/MDM2 promoted gefitinib resistance and inhibited ferroptosis in NSCLC, which might offer a novel strategy for overcoming gefitinib resistance in NSCLC.

USP22 is required for human endometrial stromal cell proliferation and decidualization by deubiquitinating FoxM1

Despite significant advances in assisted reproductive technology (ART), recurrent implantation failure (RIF) still occurs in some patients. Poor endometrial receptivity and abnormal human endometrial stromal cell (HESC) proliferation and decidualization have been identified as the major causes. Ubiquitin-specific protease 22 (USP22) has been reported to participate in the decidualization of endometrial stromal cells in mice. However, the role of USP22 in HESC function and RIF development remains unknown. In this study, clinical endometrial tissue samples were gathered to investigate the involvement of USP22 in RIF, and HESCs were utilized to examine the molecular mechanisms of USP22 and Forkhead box M1 (FoxM1). The findings indicated a high expression of USP22 in the secretory phase of the endometrium. Knockdown of USP22 led to a notable reduction in the proliferation and decidualization of HESCs, along with a decrease in FoxM1 expression, while overexpression of USP22 yielded opposite results. Furthermore, USP22 was found to deubiquitinate FoxM1 in HESCs. Moreover, both USP22 and FoxM1 were downregulated in the endometria of patients with RIF. In conclusion, these results suggest that USP22 may have a significant impact on HESCs proliferation and decidualization through its interaction with FoxM1, potentially contributing to the underlying mechanisms of RIF pathogenesis.

Itaconate alleviates anesthesia/surgery-induced cognitive impairment by activating a Nrf2-dependent anti-neuroinflammation and neurogenesis via gut-brain axis

BACKGROUND

Postoperative cognitive dysfunction (POCD) is a common neurological complication of anesthesia and surgery in aging individuals. Neuroinflammation has been identified as a hallmark of POCD. However, safe and effective treatments of POCD are still lacking. Itaconate is an immunoregulatory metabolite derived from the tricarboxylic acid cycle that exerts anti-inflammatory effects by activating the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway. In this study, we investigated the effects and underlying mechanism of 4-octyl itaconate (OI), a cell-permeable itaconate derivative, on POCD in aged mice.

METHODS

A POCD animal model was established by performing aseptic laparotomy in 18-month-old male C57BL/6 mice under isoflurane anesthesia while maintaining spontaneous ventilation. OI was intraperitoneally injected into the mice after surgery. Primary microglia and neurons were isolated and treated to lipopolysaccharide (LPS), isoflurane, and OI. Cognitive function, neuroinflammatory responses, as well as levels of gut microbiota and their metabolites were evaluated. To determine the mechanisms underlying the therapeutic effects of OI in POCD, ML385, an antagonist of Nrf2, was administered intraperitoneally. Cognitive function, neuroinflammatory responses, endogenous neurogenesis, neuronal apoptosis, and Nrf2/extracellular signal-related kinases (ERK) signaling pathway were evaluated.

RESULTS

Our findings revealed that OI treatment significantly alleviated anesthesia/surgery-induced cognitive impairment, concomitant with reduced levels of the neuroinflammatory cytokines IL-1β and IL-6, as well as suppressed activation of microglia and astrocytes in the hippocampus. Similarly, OI treatment inhibited the expression of IL-1β and IL-6 in LPS and isoflurane-induced primary microglia in vitro. Intraperitoneal administration of OI led to alterations in the gut microbiota and promoted the production of microbiota-derived metabolites associated with neurogenesis. We further confirmed that OI promoted endogenous neurogenesis and inhibited neuronal apoptosis in the hippocampal dentate gyrus of aged mice. Mechanistically, we observed a decrease in Nrf2 expression in hippocampal neurons both in vitro and in vivo, which was reversed by OI treatment. We found that Nrf2 was required for OI treatment to inhibit neuroinflammation in POCD. The enhanced POCD recovery and promotion of neurogenesis triggered by OI exposure were, at least partially, mediated by the activation of the Nrf2/ERK signaling pathway.

CONCLUSIONS

Our findings demonstrate that OI can attenuate anesthesia/surgery-induced cognitive impairment by stabilizing the gut microbiota and activating Nrf2 signaling to restrict neuroinflammation and promote neurogenesis. Boosting endogenous itaconate or supplementation with exogenous itaconate derivatives may represent novel strategies for the treatment of POCD.

Genetically engineered neural stem cells (NSCs) therapy for neurological diseases; state-of-the-art

Neural stem cells (NSCs) are multipotent stem cells with remarkable self-renewal potential and also unique competencies to differentiate into neurons, astrocytes, and oligodendrocytes (ODCs) and improve the cellular microenvironment. In addition, NSCs secret diversity of mediators, including neurotrophic factors (e.g., BDNF, NGF, GDNF, CNTF, and NT-3), pro-angiogenic mediators (e.g., FGF-2 and VEGF), and anti-inflammatory biomolecules. Thereby, NSCs transplantation has become a reasonable and effective treatment for various neurodegenerative disorders by their capacity to induce neurogenesis and vasculogenesis and dampen neuroinflammation and oxidative stress. Nonetheless, various drawbacks such as lower migration and survival and less differential capacity to a particular cell lineage concerning the disease pathogenesis hinder their application. Thus, genetic engineering of NSCs before transplantation is recently regarded as an innovative strategy to bypass these hurdles. Indeed, genetically modified NSCs could bring about more favored therapeutic influences post-transplantation in vivo, making them an excellent option for neurological disease therapy. This review for the first time offers a comprehensive review of the therapeutic capability of genetically modified NSCs rather than naïve NSCs in neurological disease beyond brain tumors and sheds light on the recent progress and prospect in this context.