Tripartite Motif 38 Attenuates Cardiac Fibrosis after Myocardial Infarction by Suppressing TAK1 Activation via TAB2/3 Degradation

Trim38 attenuates pressure overload‑induced cardiac hypertrophy by suppressing the TAK1/JNK/P38 signaling pathway

Pathological cardiac hypertrophy is a major contributor to heart failure (HF), resulting in high mortality rates worldwide; therefore, identifying key molecules in pathological cardiac hypertrophy is of critical importance for preventing or reversing HF. Tripartite motif 38 (Trim38) is an E3 ubiquitin ligase that serves a pivotal role in various diseases. The present study aimed to elucidate the regulatory role of Trim38 in pressure overload‑induced pathological cardiac hypertrophy and to explore its underlying molecular mechanisms. The expression of Trim38 was decreased in hypertrophic heart tissues from a murine model of transverse aortic constriction (TAC) and in neonatal rat cardiomyocytes (NRCMs) treated with phenylephrine (PE). Furthermore, Trim38 knockout (Trim38‑KO) aggravated cardiac hypertrophy after TAC, and Trim38 knockdown in cardiomyocytes increased cell cross section area, and upregulated the expression of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) following treatment with PE. Ubiquitinomics analysis revealed that the MAPK signaling pathway was regulated by Trim38. Furthermore, western blotting confirmed that Trim38‑KO activated TAK1 and JNK/P38. By contrast, Trim38 overexpression in NRCMs suppressed the JNK/P38 signaling pathway and inhibited the phosphorylation of TAK1. Furthermore, Trim38 knockdown resulted in a marked enhancement of TAK1 phosphorylation, concomitant with an augmentation of cardiomyocyte area and a significant upregulation of the hypertrophic biomarkers ANP and BNP. By contrast, infection with an adenovirus containing dominant‑negative TAK1 inhibited TAK1 activity, which attenuated Trim38 knockdown‑induced cardiomyocyte hypertrophy, confirming that TAK1 is a key molecule involved in the protective effects of Trim38 on cardiomyocytes. In conclusion, to the best of our knowledge, the present study is the first to reveal that Trim38 confers protection against pathological cardiac hypertrophy by inhibiting the TAK1/JNK/P38 signaling pathway; therefore, Trim38 may be a promising target for treating cardiac hypertrophy.

PANoptosis: a potential target of atherosclerotic cardiovascular disease

PANoptosis is a newly discovered cell death pathway triggered by the innate immunizer, which in turn promotes the assembly of the PANoptosome and activates downstream effectors. As a special cell death mode, it is characterized by apoptosis, pyroptosis, and necroptosis at the same time; therefore, it is not feasible to inhibit PANoptosis by suppressing a single cell death pathway. However, active ingredients targeting the PANoptosome can effectively inhibit PANoptosis.Given the importance of cell death in disease, targeting PANoptosis would be an important therapeutic tool. Previous studies have focused more on infectious diseases and cancer, and the role of PANoptosis in the cardiovascular field has not been comprehensively addressed. While ASCVD is the number one killer of cardiovascular diseases, it is important to explore new targets to determine future research directions. Therefore, this review focuses on the assembly of PANoptosome, the molecular mechanism of PANoptosis, and the related mechanisms of PANoptosis leading to ASCVD such as myocardial infarction, ischemic cardiomyopathy and ischemic stroke, in order to provide a new perspective for the prevention and treatment of ASCVD.

TRIM38 Suppresses the Progression of Colorectal Cancer via Enhancing CCT6A Ubiquitination to Inhibit the MYC Pathway

Emerging evidence reveals the pivotal function of tripartite motif protein (TRIM) in colorectal cancer (CRC). However, the precise function of TRIM38 and its underlying mechanism in CRC remains to be elucidated, especially regarding its putative ubiquitination function. Here, it is identified that TRIM38 is downregulated in CRC tissues by DNA hypermethylation of its promoter. Further analysis demonstrates that decreased TRIM38 is correlated with unfavorable clinical features and poor prognosis. Moreover, TRIM38 functions as a tumor suppressor by inhibiting cell proliferation, metastasis, and AOM/DSS-induced tumorigenesis in CRC cells. Mechanistically, TRIM38 binds to the substrate protein CCT6A, leading to the degradation and K48-linked ubiquitination of CCT6A at the K127/K138 residues. The elevation of CCT6A protein level caused by TRIM38 downregulation diminishes the degradation of c-Myc protein, thereby activating the MYC pathway. The study elucidates a novel mechanism of TRIM38/CCT6A/c-Myc axis regulating CRC, potentially offering a new therapeutic target for its treatment.

Primary culture of endometrial mesenchymal stem cells derived from ectopic lesions of patients with adenomyosis

PURPOSE

This study aimed to establish a protocol for efficiently isolating and expanding adenomyotic lesion-derived endometrial mesenchymal stem cells (A-eMSCs) in vitro.

METHODS

Three different methods-namely, the enzymatic method, the explant method, and the enzymatic explant method-were employed to isolate A-eMSCs. The isolation and expansion efficiencies of these three methods were subsequently compared. The enzymatic explant method was then used, and the transforming growth factor beta type I receptor (TGF-βR1) inhibitor A83-01 was added to the culture medium to evaluate its impact on the isolation and expansion efficiencies of A-eMSCs.

RESULTS

The enzymatic explant method resulted in improved morphology, shorter cell confluence time, and greater SUSD2 enrichment in the isolation of primary endometrial cells compared to the other two methods. The proliferation and differentiation potential of A-eMSCs obtained by sorting primary endometrial cells via the enzymatic explant method were significantly higher than those obtained via the other two methods in vitro. Using the enzymatic explant method, culture medium containing A83-01 further reduced the confluence time of the cells and increased A-eMSCs enrichment during the primary endometrial cell isolation stage. Furthermore, A83-01 enhanced the proliferation and maintained the differentiation potential of A-eMSCs during the cell expansion stage.

CONCLUSION

Our study identified a robust, cost-effective, and efficient protocol for isolating and expanding A-eMSCs and providing an important foundation for further research on the pathogenesis and clinical treatment of AM.

Silencing DOCK2 Attenuates Cardiac Fibrosis Following Myocardial Infarction in Mice Via Targeting PI3K/Akt and Wnt/β-Catenin Pathways

Cardiac fibrosis following myocardial infarction (MI) seriously affects the prognosis and survival rate of patients. This study aimed to determine the effect and regulation mechanism of the dedicator of cytokinesis 2 (DOCK2) during this process. Experiments were carried out in mice in vivo, and in Ang II treated cardiac fibroblasts (CFs) in vitro. DOCK2 was increased in mouse myocardial tissues after MI and Ang II-treated CFs. In MI mice, DOCK2 silencing improved cardiac function, and ameliorated cardiac fibrosis. DOCK2 knockdown suppressed the activation of CFs and decreased the expression of α-SMA, collagen I, and collagen III. Suppression of DOCK2 mitigated Ang II induced migration of CFs. DOCK2 inhibition reduced the activity of the PI3K/Akt and Wnt/β-catenin pathways, while this change could be reversed by the pathway activators, SC79 and SKL2001. In summary, DOCK2 suppression improves cardiac dysfunction and attenuates cardiac fibrosis after MI via attenuating PI3K/Akt and Wnt/β-catenin pathways.

TRIM35 triggers cardiac remodeling by regulating SLC7A5-mediated amino acid transport and mTORC1 activation in fibroblasts

BACKGROUND

Cardiac maladaptive remodeling is one of the leading causes of heart failure with highly complicated pathogeneses. The E3 ligase tripartite motif containing 35 (TRIM35) has been identified as a crucial regulator governing cellular growth, immune responses, and metabolism. Nonetheless, the role of TRIM35 in fibroblasts in cardiac remodeling remains elusive.

METHODS

Heart tissues from human donors were used to verify tissue-specific expression of TRIM35. Fibroblast-specific Trim35 gene knockout mice (Trim35cKO) were used to investigate the function of TRIM35 in fibroblasts. Cardiac function, morphology, and molecular changes in the heart tissues were analyzed after transverse aortic constriction (TAC) surgery. The mechanisms by which TRIM35 regulates fibroblast phenotypes were elucidated using liquid chromatography-tandem mass spectrometry (LC-MS/MS) and RNA sequencing (RNA-Seq). These findings were further validated through the use of adenoviral and adeno-associated viral transfection systems, as well as the mTORC1 inhibitor Rapamycin.

RESULTS

TRIM35 expression is primarily up-regulated in cardiac fibroblasts in both murine and human fibrotic hearts, and responds to TGF-β1 stimulation. Specific deletion of TRIM35 in cardiac fibroblasts significantly improves cardiac fibrosis and hypertrophy. Consistently, the overexpression of TRIM35 promotes fibroblast proliferation, migration, and differentiation. Through paracrine signaling, it induces hypertrophic growth of cardiomyocytes. Mechanistically, we found that TRIM35 interacts with, ubiquitinates, and up-regulates the amino acid transporter SLC7A5, which enhances amino acid transport and activates the mTORC1 signaling pathway. Furthermore, overexpression of SLC7A5 significantly reverses the reduced cardiac fibrosis and hypertrophy caused by conditional knockout of TRIM35.

CONCLUSION

Our findings demonstrate a novel role of fibroblast-TRIM35 in cardiac remodeling and uncover the mechanism underlying SLC7A5-mediated amino acid transport and mTORC1 activation. These results provide a potential novel therapeutic target for treating cardiac remodeling.

Crosstalk of ubiquitin system and non-coding RNA in fibrosis

Chronic tissue injury triggers changes in the cell type and microenvironment at the site of injury and eventually fibrosis develops. Current research suggests that fibrosis is a highly dynamic and reversible process, which means that human intervention after fibrosis has occurred has the potential to slow down or cure fibrosis. The ubiquitin system regulates the biological functions of specific proteins involved in the development of fibrosis, and researchers have designed small molecule drugs to treat fibrotic diseases on this basis, but their therapeutic effects are still limited. With the development of molecular biology technology, researchers have found that non-coding RNA (ncRNA) can interact with the ubiquitin system to jointly regulate the development of fibrosis. More in-depth explorations of the interaction between ncRNA and ubiquitin system will provide new ideas for the clinical treatment of fibrotic diseases.

Cellular and molecular mechanisms driving cardiac tissue fibrosis: On the precipice of personalized and precision medicine

Cardiac fibrosis is a significant contributor to heart failure, a condition that continues to affect a growing number of patients worldwide. Various cardiovascular comorbidities can exacerbate cardiac fibrosis. While fibroblasts are believed to be the primary cell type underlying fibrosis, recent and emerging data suggest that other cell types can also potentiate or expedite fibrotic processes. Over the past few decades, clinicians have developed therapeutics that can blunt the development and progression of cardiac fibrosis. While these strategies have yielded positive results, overall clinical outcomes for patients suffering from heart failure continue to be dire. Herein, we overview the molecular and cellular mechanisms underlying cardiac tissue fibrosis. To do so, we establish the known mechanisms that drive fibrosis in the heart, outline the diagnostic tools available, and summarize the treatment options used in contemporary clinical practice. Finally, we underscore the critical role the immune microenvironment plays in the pathogenesis of cardiac fibrosis.

Upregulation of TRIM16 mitigates doxorubicin-induced cardiotoxicity by modulating TAK1 and YAP/Nrf2 pathways in mice

The clinic application of doxorubicin (DOX) is severely limited by its severe cardiotoxicity. Tripartite motif-containing protein 16 (TRIM16) has E3 ubiquitin ligase activity and is upregulated in cardiomyocytes under pathological stress, yet its role in DOX-induced cardiotoxicity remains elusive. This study aims to investigate the role and mechanism of TRIM16 in DOX cardiotoxicity. Following TRIM16 overexpression in hearts with AAV9-TRIM16, mice were intravenously administered DOX at a dose of 4 mg/kg/week for 4 weeks to assess the impact of TRIM16 on doxorubicin-induced cardiotoxicity. Transfection of OE-TRIM16 plasmids and siRNA-TRIM16 was performed in neonatal rat cardiomyocytes (NRCMs). Our results revealed that DOX challenge elicited a significant upregulation of TRIM16 proteins in cardiomyocytes. TRIM16 overexpression efficiently ameliorated cardiac function while suppressing inflammation, ROS generation, apoptosis and fibrosis provoked by DOX in the myocardium. TRIM16 knockdown exacerbated these alterations caused by DOX in NRCMs. Mechanistically, OE-TRIM16 augmented the ubiquitination and degradation of p-TAK1, thereby arresting JNK and p38MAPK activation evoked by DOX in cardiomyocytes. Furthermore, DOX enhanced the interaction between p-TAK1 and YAP1 proteins, resulting in a reduction in YAP and Nrf2 proteins in cardiomyocytes. OE-TRIM16 elevated YAP levels and facilitated its nuclear translocation, thereby promoting Nrf2 expression and mitigating oxidative stress and inflammation. This effect was nullified by siTRIM16 or TAK1 inhibitor Takinib. Collectively, the current study elaborates that upregulating TRIM16 mitigates DOX-induced cardiotoxicity through anti-inflammation and anti-oxidative stress by modulating TAK1-mediated p38 and JNK as well as YAP/Nrf2 pathways, and targeting TRIM16 may provide a novel strategy to treat DOX-induced cardiotoxicity.

TRIM44 aggravates cardiac fibrosis after myocardial infarction via TAK1 stabilization

Myocardial infarction (MI) is one of the most dangerous cardiovascular events. Cardiac fibrosis is a common pathological feature of remodeling after injury that is related to adverse clinical results with no effective treatment. Previous studies have confirmed that TRIM44, an E3 ligase, can promote the proliferation and migration of various tumor cells. However, the role of TRIM44 in cardiac fibrosis remains unknown. Models of TGF-β1 stimulation and MI-induced fibrosis were established to investigate the role and potential underlying mechanism of TRIM44 in cardiac fibrosis. The results showed that cardiac fibrosis was significantly inhibited after TRIM44 knockdown in a mouse model of MI, while it was enhanced when TRIM44 was overexpressed. Furthermore, in vitro studies showed that fibrosis markers were significantly reduced in cardiac fibroblasts (CFs) with TRIM44 knockdown, whereas TRIM44 overexpression promoted the expression of fibrosis markers. Mechanistically, TRIM44 maintains TAK1 stability by inhibiting the degradation of k48-linked polyubiquitination-mediated ubiquitination, thereby increasing phosphorylated TAK1 expression in the fibrotic environment and activating MAPKs to promote fibrosis. Pharmacological inhibition of TAK1 phosphorylation reversed the fibrogenic effects of TRIM44 overexpression. Combined, these results suggest that TRIM44 is a potential therapeutic target for cardiac fibrosis.

Tripartite motif 38 alleviates the pathological process of NAFLD/NASH by promoting TAB2 degradation

Nonalcoholic fatty liver disease (NAFLD) has become the most prevalent chronic liver disease worldwide, without any FDA-approved pharmacological intervention in clinic. The TRIM (tripartite motif-containing) family plays essential roles in innate immune and hepatic inflammation. TRIM38, as one of the important members in TRIM family, was largely reported to be involved in the regulation of innate immune and inflammatory responses. However, the functional roles of TRIM38 in NAFLD remains largely unknown. Here, the expression of TRIM38 was first detected in liver samples of both NAFLD mice model and patients diagnosed with NAFLD. We found TRIM38 expression was downregulated in NAFLD liver tissues compared with normal liver tissues. Genetic TRIM38 knockout in vivo showed that TRIM38 depletion deteriorated the HFD and HFHC diet-induced hepatic steatosis and HFHC diet-induced liver inflammation and fibrosis. In particular, we found that the effects of hepatocellular lipid accumulation and inflammation induced by palmitic acid and oleic acid (PA+OA) was aggravated by TRIM38 depletion but mitigated by TRIM38 overexpression in vitro. Mechanically, RNA-seq analysis demonstrated that TRIM38 ameliorated NASH progression by attenuating the activating of mitogen-activated protein kinase (MAPK) signaling pathway. We further found that TRIM38 interacted with TGF-β-activated kinase 1 (TAK1) binding protein 2 (TAB2) and promoted its protein degradation, thus inhibiting the TAK1-MAPK signal cascades. In summary, our study revealed that TRIM38 could suppress hepatic steatosis, inflammatory and fibrosis in NAFLD via promoting TAB2 degradation. TRIM38 could be a potential target for NAFLD treatment.