Knockdown of TRIM8 Attenuates IL-1β-induced Inflammatory Response in Osteoarthritis Chondrocytes Through the Inactivation of NF-κB Pathway

TRIM8 enhances chondrocyte ferroptosis by inhibiting YTHDF2-m6A mediated SREBF2 mRNA degradation to promote OA progression

Chondrocyte ferroptosis plays a crucial role in osteoarthritis (OA) progression. Our previous study demonstrated that TRIM8 knockdown alleviated IL-1β-induced chondrocyte injury. However, the involvement of TRIM8 in regulating OA progression through ferroptosis remains unclear. In this study, human OA and normal cartilage samples were collected to examine ferroptosis and TRIM8 expression. We found that both ferroptosis markers and TRIM8 protein levels were elevated in OA cartilage compared to controls. An OA cell model was established by stimulating chondrocytes with IL-1β. TRIM8 knockdown mitigated IL-1β-induced ferroptosis, extracellular matrix (ECM) degradation, and inflammation in chondrocytes. Mechanistically, TRIM8 facilitated the ubiquitylation of YTHDF2 via its RING domain, promoting YTHDF2 protein degradation. This inhibited YTHDF2-m6A-induced SREBF2 mRNA degradation, thereby upregulating SREBF2 expression and enhancing chondrocyte ferroptosis. As expected, SREBF2 overexpression reversed the protective effect of TRIM8 silencing on IL-1β-induced chondrocyte injury. An OA mouse model was established using destabilized medial meniscus surgery, and TRIM8 deficiency alleviated cartilage degradation and synovial inflammation. In conclusion, TRIM8 promotes chondrocyte ferroptosis by suppressing YTHDF2-m6A mediated SREBF2 mRNA degradation, thereby accelerating OA progression.

E3 ligase TRIM8 suppresses lung cancer metastasis by targeting MYOF degradation through K48-linked polyubiquitination

Ubiquitination is a posttranslational modification that regulates tumour progression-associated proteins through the ubiquitin‒proteasome system, making E3 ligases potential antitumour targets. Here, we report that TRIM8, a member of the TRIM family and an E3 ligase, can act as a tumour suppressor in non-small cell lung cancer (NSCLC). Both gain- and loss-of-function experiments revealed that TRIM8 inhibits the proliferation, colony formation, migration and invasion of NSCLC cells. Experiments with a xenograft model showed that TRIM8 expression suppresses tumour metastasis in vivo. Moreover, low expression of TRIM8 was associated with poor overall survival in both the Taiwanese and GEO lung cancer cohorts. TRIM8 overexpression in lung cancer cells reduced MYOF expression, and restoring MYOF rescued cell migration in TRIM8-overexpressing cells. TRIM8 targeted MYOF for K48-linked ubiquitination, facilitating proteasome-mediated degradation and subsequently suppressing the extracellular secretion of MMPs. Our results provide new insights into the contribution of TRIM8 to lung cancer progression, suggesting that TRIM8 is a new biomarker and a novel therapeutic target for lung cancer.

The critical role of TRIM protein family in intervertebral disc degeneration: mechanistic insights and therapeutic perspectives

Intervertebral disc degeneration (IVDD) is a leading cause of chronic back pain, contributing significantly to reduced quality of life and global public health burdens. The TRIM (Tripartite Motif-containing) protein family, with its diverse regulatory roles, has emerged as a key player in critical cellular processes such as inflammation, cell death, and extracellular matrix (ECM) metabolism. Recent findings underscore the involvement of TRIM proteins in IVDD pathogenesis, where they regulate stress responses, maintain cellular homeostasis, and influence the functional integrity of nucleus pulposus (NP) and annulus fibrosus (AF) cells. This review explores the multifaceted roles of TRIM proteins in IVDD, highlighting their contributions to pathological pathways and their potential as therapeutic targets. Advancing our understanding of TRIM protein-mediated mechanisms may pave the way for innovative and precise therapeutic strategies to combat IVDD.

Mesoscale landscaping of the TRIM protein family reveals a novel human condensatopathy

The mesoscale organization of cells is central to cellular physiology and pathology. Cellular condensates often form via biomolecular phase separation, mediated by intrinsically disordered regions (IDRs) and represent a key mechanism for mesoscale organization. The TRI-partite Motif (TRIM) family of ubiquitin ligases is implicated in diverse cellular functions and disease, yet the role of biomolecular condensation in TRIM family organization remains understudied. Here, we systematically investigate the mesoscale localization of 72 TRIM proteins, revealing that a majority form condensates in distinct cellular compartments. IDR content correlates with dynamic condensate formation, suggesting a critical role in mesoscale organization. Focusing on TRIM8, associated with a neuro-renal disorder, we demonstrate that disease-causing truncations of the TRIM8 C-terminal IDR result in a condensatopathy , characterized by disrupted condensation, proteasomal regulation, and TAK1/NFκB signaling. Functional assays in cellular and animal models link these disruptions to podocyte dysfunction and impaired response to injury. Our findings establish a framework for understanding condensatopathies and the mesoscale principles governing TRIM family organization and function.

Silencing TRIM8 alleviates allergic asthma and suppressing Th2 differentiation through inhibiting NF-κB/NLRP3 signaling pathway

BACKGROUND AND AIM

Allergic asthma is a primary type of asthma and characterized by T helper 2 (Th2) cells -mediated inflammation. Tripartite motif containing 8 (TRIM8) protein is involved in immunoreaction and inflammatory response in many diseases. However, its role in allergic asthma remains unclear. Medical databank showed that TRIM8 was increased in lung of ovalbumin (OVA)-challenged mice. This study aimed to elucidate the effects of TRIM8 on allergic asthma and Th2 development.

METHODS

Asthma were induced by OVA challenge in mice, and the adenovirus vector loaded with TRIM8 knockdown sequence was delivered into asthma mice by nasal inhalation. The percentage of Th2 cells in lung was assessed by flow cytometric analysis, and the contents of Th2 cytokines (interleukin (IL)-4, IL-5 and IL-13) in bronchoalveolar lavage fluid (BALF) were assessed with ELISA. In vitro Th2 induction was performed in CD4+ cells from mouse spleen, the expression of Th2 molecules (IL-4, IL-5 and GATA binding protein 3 (GATA3)) were measured by real-time PCR. In addition, the nuclear factor-kappa B (NF-κB)/nucleotide-binding oligomerization domain, leucine rich repeat and pyrin domain containing 3 (NLRP3) signaling was determined.

RESULTS

TRIM8 was highly expressed in the lung tissues of asthmatic mice and Th2-induced CD4+ cells. OVA challenge-induced Th2 development and Th2 cytokine secretion were restrained by silencing of TRIM8 in vivo. Similarly, the Th2 differentiation in vitro was also suppressed by TRIM8 knockdown. TRIM8 inhibited the NF-κB/NLRP3 activity by blocking transforming growth factor-beta-activated kinase 1 (TAK1), and the effects of TRIM8 were abrogated by overexpression of NLRP3.

CONCLUSIONS

Silencing TRIM8 relieved the asthmatic injury in mice and excessive Th2 development via inhibiting the NF-κB/NLRP3 pathway. It is indicated that TRIM8 may contribute to the airway inflammation in allergic asthma via activating the NF-κB/NLRP3 signaling pathway. The current study provided a novel potential target for allergic asthma treatment.

[Xinfeng Capsule alleviates interleukin-1β-induced chondrocyte inflammation and extracellular matrix degradation by regulating the miR-502-5p/TRAF2/NF-κB axis]

OBJECTIVE

To investigate the mechanism that mediates the inhibitory effect of Xinfeng Capsule (XFC) on interleukin (IL)-1β-induced impairment of chondrocytes.

METHODS

XFC-medicated serum was collected from SD rats with XFC gavage, and its optimal concentration for chondrocyte treatment was determined using Cell Counting Kit-8 assay and flow cytometry. Dual luciferase reporter analysis was performed to analyze the targeting relationship between miR-502-5p and TRAF2. In cultured human chondrocytes induced with IL-1β, the effects of transfection with miR-502-5p inhibitor and XFC-medicated serum, alone or in combination, on expression levels of IL-1β, tumor necrosis factor-α (TNF-α), IL-4, and IL-10 were examined with ELISA, and the changes in the expressions of collagen type Ⅱ alpha 1 (COL2A1), matrix metalloproteinase 13 (MMP13), adisintegrin and metalloproteinase with thrombospondin motifs 5 (ADAMTS5), and miR-502-5p/TRAF2/NF-κB axis gene expression were detected using RT-qPCR, Western blotting, and immunofluorescence assay.

RESULTS

In cultured human chondrocytes, treatment with IL-1β significantly decreased the cell viability, increased cell apoptosis rate, lowered miR-502-5p, IL-4, IL-10, and COL2A1 expressions, and enhanced IL-1β, TNF-α, ADAMTS5, MMP13, TRAF2, and NF-κB p65 expressions (P < 0.05), and these changes were significantly improved by treatment with XFC-medicated serum at the optimal concentration of 20% (P < 0.05). Transfection of the chondrocytes with miR-502-5p inhibitor resulted in elevated expressions of IL-1β, TNF-α, ADAMTS5, MMP13, TRAF2, and NF-κB p65 and lowered expressions of miR-502-5p, IL-4, IL-10, and COL2A1, and XFC-medicated serum obviously reversed the effects of miR-502-5p inhibitor.

CONCLUSION

XFC can inhibit IL-1β-induced inflammatory response and ECM degradation in cultured human chondrocytes possibly by regulating the miR-502-5p/TRAF2/NF-κB axis.

Emerging Roles of TRIM8 in Health and Disease

The superfamily of TRIM (TRIpartite Motif-containing) proteins is one of the largest groups of E3 ubiquitin ligases. Among them, interest in TRIM8 has greatly increased in recent years. In this review, we analyze the regulation of TRIM8 gene expression and how it is involved in many cell reactions in response to different stimuli such as genotoxic stress and attacks by viruses or bacteria, playing a central role in the immune response and orchestrating various fundamental biological processes such as cell survival, carcinogenesis, autophagy, apoptosis, differentiation and inflammation. Moreover, we show how TRIM8 functions are not limited to ubiquitination, and contrasting data highlight its role either as an oncogene or as a tumor suppressor gene, acting as a “double-edged weapon”. This is linked to its involvement in the selective regulation of three pivotal cellular signaling pathways: the p53 tumor suppressor, NF-κB and JAK-STAT pathways. Lastly, we describe how TRIM8 dysfunctions are linked to inflammatory processes, autoimmune disorders, rare developmental and cardiovascular diseases, ischemia, intellectual disability and cancer.