Rationale: Myocardial ischemia/reperfusion (I/R) injury leads to irreversible cardiomyocyte death and aggravates myocardial infarction. Deubiquitinating enzymes (DUBs) are essential for maintaining substrate protein stability and functionality, playing significant roles in cardiac pathophysiology. In this study, we aimed to clarify the regulatory role of a DUB, Myb-like, SWIRM, and MPN domains 1 protein (MYSM1), in myocardial I/R injury and explore the molecular mechanism behind. Methods and Results: Firstly, it was found that the expression of MYSM1 positively correlates with myocardial I/R injury. Genetic knockdown of MYSM1 significantly conferred protection against I/R injury in hearts. Correspondingly, AAV9-mediated cardiomyocyte-specific knockdown of MYSM1 had a therapeutic effect on myocardial I/R injury. Through a comprehensive proteome-wide quantitative analysis, we identified signal transducer and activator of transcription 1 (STAT1) as the direct substrate of MYSM1. Mechanistically, MYSM1 mediated the K63-linked deubiquitination and stabilization of STAT1 at position K379 via its MPN metalloprotease domain. Additionally, MYSM1 initiates the expression of necroptosis-related genes by promoting the transcription factor function of STAT1. Conclusion: This study illustrated a MYSM1-STAT1 axis in regulating myocardial I/R injury and identified MYSM1 as a pharmacological target for myocardial I/R injury.

Recent studies have shown the crucial role of podocyte injury in the development of diabetic kidney disease (DKD). Deubiquitinating modification of proteins is widely involved in the occurrence and development of diseases. Here, we explore the role and regulating mechanism of a deubiquitinating enzyme, OTUD5, in podocyte injury and DKD. RNA-seq analysis indicates a significantly decreased expression of OTUD5 in HG/PA-stimulated podocytes. Podocyte-specific Otud5 knockout exacerbates podocyte injury and DKD in both type 1 and type 2 diabetic mice. Furthermore, AVV9-mediated OTUD5 overexpression in podocytes shows a therapeutic effect against DKD. Mass spectrometry and co-immunoprecipitation experiments reveal an inflammation-regulating protein, TAK1, as the substrate of OTUD5 in podocytes. Mechanistically, OTUD5 deubiquitinates K63-linked TAK1 at the K158 site through its active site C224, which subsequently prevents the phosphorylation of TAK1 and reduces downstream inflammatory responses in podocytes. Our findings show an OTUD5-TAK1 axis in podocyte inflammation and injury and highlight the potential of OTUD5 as a promising therapeutic target for DKD. Deubiquitinating of key proteins may be involved in podocyte injury and diabetic kidney disease (DKD). Here, the authors show that OTUD5 in podocytes alleviates DKD through deubiquitinating TAK1 at the K158 site, preventing TAK1 phosphorylation and inflammatory responses in podocytes.

Macrophage is a vital factor in determining the fate of abdominal aortic aneurysm (AAA). The crosstalk between macrophage and other cells plays a crucial role in the development of aneurysm. Gasdermin D (GSDMD) is a vital executive protein of pyroptosis, which is a novel programmed cell death associated with inflammation. In this study, we identified aortic macrophage as the main expressing cell of GSDMD in AAA. Using Gsdmd-/-ApoE-/- mouse and AAV-F4/80-shGSDMD, we demonstrated the potential role of macrophage-derived GSDMD in AAA and aortic pyroptosis induced by Ang II in vivo. In vitro experiments showed that GSDMD promotes the pyroptosis of mouse primary peritoneal macrophages (MPMs), murine aortic vascular smooth muscle cells (MOVAS) and primary smooth muscle cells. Mechanistically, a mouse cytokine antibody array showed that Gsdmd-/- inhibited LPS + nigericin (LN)- induced secretion of multiple cytokines from MPMs. Furthermore, GSDMD is involved in the crosstalk between MPMs and MOVAS via cytokine secretion. This study provides a novel fundamental insight into macrophage-derived GSDMD in AAA and showed that GSDMD could be a promising therapeutic target for AAA.

Rationale: Cardiac hypertrophy is an important pathological basis for heart failure. Most physiological activities of cardiomyocytes are regulated by proteins and their post-translational modification. Deubiquitinating enzymes (DUBs) are involved in protein stability maintenance and closely related to myocardial hypertrophy. In this study, we aimed to clarify the regulatory role of a DUB, ubiquitin-specific peptidase 28 (USP28), in cardiac hypertrophy and explore the molecular mechanism behind. Methods: Transcriptome and single-cell mRNA sequencing was used to demonstrate the association of USP28 and cardiac hypertrophy. Cardiomyocyte-specific USP28 knockout mice (USP28CKO) were subjected to angiotensin II (Ang II) infusion or transverse aortic constriction (TAC) models. Coimmunoprecipitation combined mass spectrum analysis (Co-IP/MS) was applied to screen out the substrate of USP28. Results: We first showed the up-regulation of USP28 in cardiac hypertrophy, and its cellular localization of cardiomyocytes. USP28CKO protects mouse heart against Ang II- or TAC-induced cardiac dysfunction and hypertrophy. Mechanistically, we identified tripartite motif-containing protein 21 (TRIM21) as the potential substrate of USP28 by Co-IP/MS analysis. Cardiomyocyte USP28 deubiquitinates and stabilizes TRIM21 to negatively regulate nuclear factor erythroid 2-related factor 2 (Nrf2) antioxidant response, increasing oxidative stress in cardiomyocytes and promoting cardiac hypertrophy and injury. Finally, using a selective USP28 inhibitor Otilonium Bromide, we confirmed the therapeutic effect of pharmacological inhibition of USP28 against TAC-induced established hypertrophic heart failure. Conclusion: Our study illustrates a cardiomyocyte-specific USP28-TRIM21 axis in regulating hypertrophic cardiomyopathy and presents USP28 as a potential target for the treatment of cardiac hypertrophy.

Anthracycline antitumor drug doxorubicin (DOX) induces severe cardiotoxicity. Deubiquitinating enzymes (DUBs) are crucial for protein stability and function and play a significant role in cardiac pathophysiology. By comparing RNA sequencing datasets and conducting functional screening, we determined that Myb-like, SWIRM, and MPN domains 1 (MYSM1) is a key regulator of DOX-induced cardiotoxicity. In this study, we aimed to explore the function and regulatory mechanisms of MYSM1 in DOX-induced cardiotoxicity. Genetic knockdown of MYSM1 significantly mitigated DOX-induced cardiomyopathy. Correspondingly, cardiomyocyte-specific knockdown of MYSM1 by AAV9 protected the heart from DOX-induced cardiotoxicity. Gain- and loss-of-function analysis verified that MYSM1 mediated DOX-induced cardiomyocyte injury in vitro. Through a Co-IP combined with LC-MS/MS analysis, we discovered that MYSM1 directly interacted with tripartite motif-containing protein 21 (TRIM21). Mechanistic investigations revealed that MYSM1 regulates the deubiquitination and the stability of TRIM21 via its MPN domain. Furthermore, MYSM1 exacerbated DOX-induced cardiotoxicity by enhancing ferroptosis. This study identified MYSM1 as a potential therapeutic target for DOX-induced cardiotoxicity and illustrated a MYSM1-TRIM21-ferroptosis axis in regulating DOX-induced cardiotoxicity.

Chronic inflammation is a significant contributor to hypertensive heart failure. Carnosol (Car), primarily derived from the sage plant (Salvia carnosa), exhibits anti-inflammatory properties in a range of systems. Nevertheless, the influence of angiotensin II (Ang II) on cardiac remodeling remains uncharted. Car was shown to protect mice's hearts against Ang II-induced heart damage at dosages of 20 and 40 mg/kg/d. This protection was evident in a concentration-related decrease in the remodeling of the heart and dysfunction. Examination of the transcriptome revealed that the pivotal roles in mediating the protective effects of Car involved inhibiting Ang IIinduced inflammation and the activation of the mitogen-activated protein kinase (MAPK) pathway. Furthermore, Car was found to inhibit p38 phosphorylation, therefore reducing the level of inflammation in cultured cardiomyocytes and mouse hearts. This effect was attributed to the direct binding to p38 and inhibition of p38 protein phosphorylation by Car both in vitro and in vivo. In addition, the effects of Car on inflammation were neutralized when p38 was blocked in cardiomyocytes.

Background: Cardiac hypertrophy is a crucial pathological characteristic of hypertensive heart disease and subsequent heart failure. Deubiquitinating enzymes (DUBs) have been found to be involved in the regulation of myocardial hypertrophy. OTU Domain -Containing Protein 6a (OTUD6a) is a recently identified DUB. To date, the potential role of OTUD6a in myocardial hypertrophy has not yet been revealed. Methods and results: We examined the up -regulated level of OTUD6a in mouse or human hypertrophic heart tissues. Then, transverse aortic constriction (TAC)- or angiotensin II (Ang II)- induced ventricular hypertrophy and dysfunction were significantly attenuated in OTUD6a gene knockout mice (OTUD6a-/-). In mechanism, we identified that the Stimulator of Interferon Genes (STING) is a direct substrate protein of OTUD6a via immunoprecipitation assay and mass spectrometry. OTUD6a maintains STING stability via clearing the K48 -linked ubiquitin in cardiomyocytes. Subsequently, OTUD6a regulates the STING -downstream NF-kappa B signaling activation and inflammatory gene expression both in vivo and in vitro. Inhibition of STING blocked OTUD6a overexpression-induced inflammatory and hypertrophic responses in cardiomyocytes. Conclusion: This finding extends our understanding of the detrimental role of OTUD6a in myocardial hypertrophy and identifies STING as a deubiquinating substrate of OTUD6a, indicating that targeting OTUD6a could be a potential strategy for the treatment of cardiac hypertrophy.

Atherosclerosis is a common chronic inflammatory disease. Recent studies have highlighted the key role of macrophages and inflammation in process of atherosclerotic lesion formation. A natural product, tussilagone (TUS), has previously exhibited anti-inflammatory activities in other diseases. In this study, we explored the potential effects and mechanisms of TUS on the inflammatory atherosclerosis. Atherosclerosis was induced in ApoE-/- mice by feeding them with a high-fat diet (HFD) for 8 weeks, followed by administration of TUS (10, 20 mg ·kg-1·d-1, i.g.) for 8 weeks. We demonstrated that TUS alleviated inflammatory response and reduced atherosclerotic plaque areas in HFD-fed ApoE-/- mice. Pro-inflammatory factor and adhesion factors were inhibited by TUS treatment. In vitro, TUS suppressed foam cell formation and oxLDL-induced inflammatory response in MPMs. RNA-sequencing analysis indicated that MAPK pathway was related to the anti-inflammation and anti-atherosclerosis effects of TUS. We further confirmed that TUS inhibited MAPKs phosphorylation in plaque lesion of aortas and cultured macrophages. MAPK inhibition blocked oxLDL-induced inflammatory response and prevented the innately pharmacological effects of TUS. Our findings present a mechanistic explanation for the pharmacological effect of TUS against atherosclerosis and indicate TUS as a potentially therapeutic candidate for atherosclerosis.

Atherosclerosis is a chronic inflammatory disease with high morbidity and mortality rates worldwide. Doublecortin‐like kinase 1 (DCLK1), a microtubule‐associated protein kinase, is involved in neurogenesis and human cancers. However, the role of DCLK1 in atherosclerosis remains undefined. In this study, we identified upregulated DCLK1 in macrophages in atherosclerotic lesions of ApoE−/− mice fed an HFD and determined that macrophage‐specific DCLK1 deletion attenuates atherosclerosis by reducing inflammation in mice. Mechanistically, RNA sequencing analysis indicated that DCLK1 mediates oxLDL‐induced inflammation via NF‐κB signaling pathway in primary macrophages. Coimmunoprecipitation followed by LC–MS/MS analysis identified IKKβ as a binding protein of DCLK1. We confirmed that DCLK1 directly interacts with IKKβ and phosphorylates IKKβ at S177/181, thereby facilitating subsequent NF‐κB activation and inflammatory gene expression in macrophages. Finally, a pharmacological inhibitor of DCLK1 prevents atherosclerotic progression and inflammation both in vitro and in vivo. Our findings demonstrated that macrophage DCLK1 promotes inflammatory atherosclerosis by binding to IKKβ and activating IKKβ/NF‐κB. This study reports DCLK1 as a new IKKβ regulator in inflammation and a potential therapeutic target for inflammatory atherosclerosis.