TRIM8: Making the Right Decision between the Oncogene and Tumour Suppressor Role

TRIM8 Promotes Proliferation, Invasion, and Migration of Cervical Cancer Cells by Ubiquitinating and Degrading SOCS1

Cervical cancer (CC) is a malignant tumor primarily caused by the persistent infection with high-risk strains of human papillomavirus. This study investigates the aberrant expression of Tripartite Motif Containing 8 (TRIM8) in CC and its impact on cell proliferation, invasion, and migration. Expression levels of TRIM8, Proliferating Cell Nuclear Antigen, and Suppressor of Cytokine Signaling 1 (SOCS1) were assessed in CC cell lines. CC cells were transfected with si-TRIM8, followed by cell counting kit-8 (CCK-8) assay, colony formation assay, and Transwell assay. Protein immunoprecipitation assay was employed to examine TRIM8's binding with SOCS1, and the ubiquitination level of SOCS1 was determined after MG132 treatment. Rescue experiments were conducted using si-SOCS1 and si-TRIM8 in combination. Results indicate upregulation of TRIM8 in CC cells. Inhibition of TRIM8 suppressed cell viability, proliferation, invasion, and migration. TRIM8 promoted CC cell proliferation, invasion, and migration of CC cells through ubiquitination-mediated degradation of SOCS1. Inhibition of SOCS1 partially reversed the inhibitory effects of si-TRIM8 on the proliferation, invasion, and migration of CC cells. In conclusion, TRIM8 enhances CC cell proliferation, invasion, and migration via ubiquitination-mediated degradation of SOCS1.

TRIM8 promotes ovarian cancer proliferation and migration by targeting VDAC2 for ubiquitination and degradation

BACKGROUND

Ovarian cancer is a common gynecological tumor with high malignant potential and poor prognosis. TRIM8, is involved in the development of various tumors, but its precise regulatory role in ovarian cancer is still unknown.

AIMS

The aim of this study was to explore the specific mechanism by which TRIM8 regulates ovarian cancer.

MATERIALS AND METHODS

We used bioinformatics analysis to screen for high expression of TRIM8 in ovarian cancer. The expression of TRIM8 in healthy and cancerous ovarian tissues was assessed by immunofluorescence. TRIM8 was silenced or overexpressed in ovarian cancer cell lines, with cell proliferation and migration evaluated by CCK8, transwell and clonal formation assays. The effect of TRIM8 on ovarian cancer cells in vivo was assessed by subcutaneous tumor formation experiments in nude mice. The potential interacting protein VDAC2 was identified by mass spectrometry. The mechanism underlying TRIM8 regulation of VDAC2 was evaluated by co-immunoprecipitation and western blotting.

RESULTS

TRIM8 was overexpressed in ovarian cancer. TRIM8 promoted the proliferation and migration of ovarian cancer cells in vitro and the growth of subcutaneous tumors in mice in vivo. TRIM8 interacted with VDAC2, weakened the stability of the protein, and promoted its polyubiquitination and subsequent degradation. Knockdown of VDAC2 increased the resistance of ovarian cancer cells to iron death, whereas overexpression of VDAC2 attenuated ovarian cancer progression induced by TRIM8 overexpression.

DISCUSSION

TRIM8 promotes ovarian cancer proliferation and migration by targeting VDAC2 for ubiquitination and degradation, these finding may provide new targets for the treatment of ovarian cancer.

CONCLUSION

TRIM8 degraded VDAC2 through the ubiquitination pathway, increased the resistance of ovarian cancer cells to iron death, and promoted the proliferation and migration of ovarian cancer.

Mutual regulation between TRIM21 and TRIM8 via K48-linked ubiquitination

Tripartite motif (TRIM)-containing proteins, one of the largest subfamilies of the RING type E3 ubiquitin ligases, control important biological processes such as cell apoptosis, autophagy, signal transduction, innate immunity and tumorigenesis. So far, the mutual regulation between TRIM family members has rarely been reported. Here, we found for the first time that there was a direct mutual regulation between TRIM21 and TRIM8 in lung and renal cancer cells, mechanistically by activating their proteasome pathway via Lys48 (K48)- linked ubiquitination. Subsequent studies verified that negatively correlated expressions existed in clinical non-small cell lung cancer (NSCLC) and renal cell carcinoma (RCC) tissues, which were closely related to tumor progression. Our findings highlighted a possible homeostasis between TRIM21 and TRIM8 that might possibly affect cell stemness and was expected to provide a new idea for cancer therapy.

De novo truncating variants of TRIM8 and atypical neuro-renal syndrome: a case report and literature review

BACKGROUND

The TRIM8 gene encodes a protein that participates in various biological processes. TRIM8 variants can lead to early termination of protein translation, which can cause a rare disease called neuro-renal syndrome. This syndrome is characterized by epilepsy, psychomotor retardation, and focal segmental glomerulosclerosis. However, we found that some patients may not present the above typical triad, and the reason may be related to their variant sites.

CASE PRESENTATION

We report a case of a 6-year-old boy with nephrotic-range proteinuria as the first prominent manifestation of TRIM8 variant. He had stage 3 chronic kidney disease at the time of presentation, specific facial features, and a neurogenic bladder. He had not experienced seizures previously. There were no apparent abnormalities in his growth, intelligence, or motor development. The results of whole exome sequencing showed a TRIM8 variant. Renal biopsy revealed focal segmental glomerulosclerosis and renal tubular cystic dilatation. He did not respond to hormone and angiotensin-converting enzyme inhibitor treatment; however, the symptoms of neurogenic bladder were relieved after treatment with Solifenacin.

CONCLUSION

In this case, renal disease was the prominent manifestation; the patient had no other obvious neurological symptoms except a neurogenic bladder. Notably, the variant site is the closest to the C-terminal to date. Based on the analysis of previously reported cases, we found that as the TRIM8 variant became closer to the C-terminal, the renal lesions became more prominent, and there were fewer neurologic lesions. Our findings provide a new understanding of neuro-renal syndrome caused by TRIM8 variant. Patients may only have kidney disease as a prominent manifestation. At the same time, we found that we should also pay attention to the eye lesions of these patients. Therefore, gene analysis is helpful in identifying the etiology and guiding the prognosis of patients with hormone-resistant proteinuria. We suggest that TRIM8 should be included in gene panels designed for the genetic evaluation of hormone-resistant proteinuria.

Knockdown of TRIM8 alleviates dextran sulfate sodium-induced colitis in mice by inhibiting the NF-κB signaling pathway

BACKGROUND

Although TRIpartite Motif containing 8 (TRIM8) gene plays an important role in a number of biological processes, such as inflammation, its function and mechanism in ulcerative colitis (UC) remain unknown.

METHODS

The UC model was established by feeding mice with 3.5% dextran sulfate sodium (DSS). The animals were divided into the following four groups: control group, DSS group, DSS+short hairpin (sh)-NC group, and DSS+sh-TRIM8 group. Changes in body weight and disease activity index (DAI) score of mice in all the groups were recorded for 7 days. The animals were executed at the end of the experiment, and the expression of TRIM8 in colon tissue was detected by polymerase chain reaction and Western blot assays. The length of colon was measured, and the histopathological changes in mice colon were examined by hematoxylin and eosin staining. The expression of pro-inflammatory factors in mice serum and colonic tissue homogenate was detected by enzyme-linked-immunosorbent serologic assay. The expression of nuclear factor kappa B (NF-κB) pathway-related proteins in colonic tissues was detected by Western-blot analysis.

RESULTS

TRIM8 was highly expressed in the colonic tissues of UC mice. Knockdown of TRIM8 improved DSS-induced weight loss, increased DAI score, shortened colon length, and alleviated colonic injury and inflammation in mice. Western-blot experiments showed that knockdown of TRIM8 inhibited DSS-induced phosphorylation of p65 and nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha (IκBα) protein but increased IκBα expression.

CONCLUSION

Knockdown of TRIM8 inhibits UC injury and inflammatory response caused by DSS. This could be related to the regulation of NF-κB signaling pathway by TRIM8 protein.

Identification and validation of novel biomarker TRIM8 related to cervical cancer

Background

Cervical cancer, as a common gynecological disease, endangers female health. Give the lack of effective biomarkers for the diagnosis and treatment of cervical cancer, this paper aims to analyze the Gene Expression Omnibus (GEO) data sets using comprehensive bioinformatics tools, and to identify biomarkers associated with the cancer in patient samples.

Methods

The bioinformatics methods were used to extract genes related to cervical cancer from GSE39001, while the GEO2R online tool to elaborate on differentially expressed genes (DEGs) in normal and cancer samples, and to clarify related genes and functions. The results were verified by IHC, WB, CCK-8, clone formation and flow cytometry experiments.

Results

A total of 2,859 DEGs were identified in the GEO microarray dataset. We extracted genes associated with both ubiquitination and autophagy from the key modules of weighted gene co-expression network analysis (WGCNA), and the analysis showed that TRIM8 was of great significance for the diagnosis and prognosis of cervical cancer. Besides, experimental validation showed the high TRIM8 expression in cervical cancer, as well as its involvement in the proliferation of cervical cancer cells.

Conclusion

We identified a biomarker (TRIM8) that may be related to cervical cancer through a series of analyses on the GEO dataset. Experimental verification confirmed the inhibition of cervical cancer cells proliferation by lowering TRIM8 expression. Therefore, TRIM8 can be adopted as a new biomarker of cervical cancer to develop new therapeutic targets.

Knockdown of TRIM8 Protects HK-2 Cells Against Hypoxia/Reoxygenation-Induced Injury by Inhibiting Oxidative Stress-Mediated Apoptosis and Pyroptosis via PI3K/Akt Signal Pathway

Background

Acute kidney injury (AKI) emerges as an acute and critical disease. Tripartite motif 8 (TRIM8), one number of the TRIM protein family, is proved to participate in ischemia/reperfusion (I/R) injury. However, whether TRIM8 is involved in renal I/R injury and the associated mechanisms are currently unclear.

Purpose

This study aimed to investigate the precise role of TRIM8 and relevant mechanisms in renal I/R injury.

Materials and Methods

In this study, human renal proximal tubular epithelial cells (HK-2 cells) underwent 12 hours of hypoxia and 2 h, 3 h or 4 h of reoxygenation to establish an in vitro hypoxia/reoxygenation (H/R) model. The siRNAs specific to TRIM8 (si-TRIM8) were transfected into HK-2 cells to knockdown TRIM8. The cell H/R model included various groups including Control, H/R, H/R+DMSO, H/R+NAC, si-NC+H/R, si-TRIM8+H/R and si-TRIM8+LY294002+H/R. The cell viability and levels of reactive oxygen species (ROS), hydrogen peroxide (H₂O₂), mRNA, apoptotic proteins, pyroptosis-related proteins and PI3K/AKT pathway-associated proteins were assessed.

Results

In vitro, realtime-quantitative PCR and western-blot analysis showed that the mRNA and protein expression of TRIM8 were obviously upregulated after H/R treatment in HK-2 cells. Compared with the H/R model group, knockdown of TRIM8 significantly increased cell viability and reduced the levels of ROS, H₂O₂, apoptotic proteins (Cleaved caspasebase-3 and BAX) and pyroptosis-related proteins (NLRP3, ASC, Caspase-1, Caspase-11, IL-1β and GSDMD-N). Western-blot analysis also authenticated that PI3K/AKT pathway was activated after TRIM8 inhibition. The application of 5 mM N-acetyl-cysteine, one highly efficient ROS inhibitor, significantly suppressed the expression of apoptotic proteins and pyroptosis-related proteins. Moreover, the combined treatment of TRIM8 knockdown and LY294002 reversed the effects of inhibiting oxidative stress.

Conclusion

Knockdown of TRIM8 can alleviate H/R-induced oxidative stress by triggering the PI3K/AKT pathway, thus attenuating pyropyosis and apoptosis in vitro.

Integrated genomics point to immune vulnerabilities in pleural mesothelioma

Pleural mesothelioma is an aggressive malignancy with limited effective therapies. In order to identify therapeutic targets, we integrated SNP genotyping, sequencing and transcriptomics from tumours and low-passage patient-derived cells. Previously unrecognised deletions of SUFU locus (10q24.32), observed in 21% of 118 tumours, resulted in disordered expression of transcripts from Hedgehog pathways and the T-cell synapse including VISTA. Co-deletion of Interferon Type I genes and CDKN2A was present in half of tumours and was a predictor of poor survival. We also found previously unrecognised deletions in RB1 in 26% of cases and show sub-micromolar responses to downstream PLK1, CHEK1 and Aurora Kinase inhibitors in primary mesothelioma cells. Defects in Hippo pathways that included RASSF7 amplification and NF2 or LATS1/2 mutations were present in 50% of tumours and were accompanied by micromolar responses to the YAP1 inhibitor Verteporfin. Our results suggest new therapeutic avenues in mesothelioma and indicate targets and biomarkers for immunotherapy.

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

Osteoarthritis (OA) is a degenerative joint disease associated with inflammatory response. Tripartite motif 8 (TRIM8) is a member of TRIM family that has been found to regulate inflammation. The present study was aimed to evaluate the role of TRIM8 in OA chondrocytes. Our results showed that TRIM8 expression was significantly increased in interleukin 1 beta (IL-1β)-stimulated OA chondrocytes. To knock down the TRIM8 expression in chondrocytes, the chondrocytes were transfected with si-TRIM8. Knockdown of TRIM8 attenuated IL-1β-induced production of inflammatory mediators including nitric oxide and prostaglandin E₂. The increased expression levels of inducible nitric oxide synthase and cyclooxygenase-2 in IL-1β-induced chondrocytes were suppressed by TRIM8 knockdown. The IL-1β-induced production of proinflammatory cytokines including TNF-α and IL-6 was significantly decreased after transfection with si-TRIM8. Besides, knockdown of TRIM8 mitigated the IL-1β-induced decrease in aggrecan and collagen-II proteins expression and increase in matrix-degrading enzymes in chondrocytes. Furthermore, TRIM8 knockdown prevented IL-1β-induced nuclear factor kappa B (NF-κB) activation in chondrocytes. Taken together, these findings indicated that knockdown of TRIM8 attenuates IL-1β-induced inflammatory response in OA chondrocytes through the inactivation of NF-κB pathway. Thus, targeting TRIM8 might provide therapeutic treatment for OA.

Knockdown of Tripartite Motif 8 Protects H9C2 Cells Against Hypoxia/Reoxygenation-Induced Injury Through the Activation of PI3K/Akt Signaling Pathway

Tripartite motif 8 (TRIM8) is a member of the TRIM protein family that has been found to be implicated in cardiovascular disease. However, the role of TRIM8 in myocardial ischemia/reperfusion (I/R) has not been investigated. We aimed to explore the effect of TRIM8 on cardiomyocyte H9c2 cells exposed to hypoxia/reoxygenation (H/R). We found that TRIM8 expression was markedly upregulated in H9c2 cells after stimulation with H/R. Gain- and loss-of-function assays proved that TRIM8 knockdown improved cell viability of H/R-stimulated H9c2 cells. In addition, TRIM8 knockdown suppressed reactive oxygen species production and elevated the levels of superoxide dismutase and glutathione peroxidase. Knockdown of TRIM8 suppressed the caspase-3 activity, as well as caused significant increase in bcl-2 expression and decrease in bax expression. Furthermore, TRIM8 overexpression exhibited apposite effects with knockdown of TRIM8. Finally, knockdown of TRIM8 enhanced the activation of PI3K/Akt signaling pathway in H/R-stimulated H9c2 cells. Inhibition of PI3K/Akt by LY294002 reversed the effects of TRIM8 knockdown on cell viability, oxidative stress, and apoptosis of H9c2 cells. These present findings defined TRIM8 as a therapeutic target for attenuating and preventing myocardial I/R injury.

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.

TRIM Proteins in Colorectal Cancer: TRIM8 as a Promising Therapeutic Target in Chemo Resistance

Colorectal cancer (CRC) represents one of the most widespread forms of cancer in the population and, as all malignant tumors, often develops resistance to chemotherapies with consequent tumor growth and spreading leading to the patient’s premature death. For this reason, a great challenge is to identify new therapeutic targets, able to restore the drugs sensitivity of cancer cells. In this review, we discuss the role of TRIpartite Motifs (TRIM) proteins in cancers and in CRC chemoresistance, focusing on the tumor-suppressor role of TRIM8 protein in the reactivation of the CRC cells sensitivity to drugs currently used in the clinical practice. Since the restoration of TRIM8 protein levels in CRC cells recovers chemotherapy response, it may represent a new promising therapeutic target in the treatment of CRC.

TRIM8 inhibits breast cancer proliferation by regulating estrogen signaling

Breast cancer (BC) is the most common female malignancy worldwide, and 70% of which are estrogen receptor α (ERα) positive. Endocrine treatment, such as tamoxifen, is a primary adjuvant therapy for patients with ER-positive BC. However, some patients will develop acquired resistance following long-time treatment. Further research on estrogen signaling is important to improve the therapy of these patients. In this study, we report that the E3 ubiquitin ligase tripartite motif 8 (TRIM8) acts as a novel regulator of ERα signaling. TRIM8 is downregulated in BC and is associated with poor prognosis. In addition, the protein level of TRIM8 is negatively correlated with ERα. RNA sequencing revealed that estrogen signaling maybe a potential target of TRIM8. Moreover, knockdown of TRIM8 can significantly enhance BC cell proliferation and migration both in vitro and in vivo. And this effect can be reversed by ERα depletion. Further mechanistic studies showed that TRIM8 interacts with AF1 domain of ERα via its RING domain in the cytoplasm and increases poly-ubiquitination of the ERα protein. In conclusion, our study reveals an interesting post-translational mechanism between ERα and TRIM8 in ER-positive BC, which suggests that TRIM8 may be a potential therapeutic target in the treatment of BC.

MuRF1/TRIM63, Master Regulator of Muscle Mass

The E3 ubiquitin ligase MuRF1/TRIM63 was identified 20 years ago and suspected to play important roles during skeletal muscle atrophy. Since then, numerous studies have been conducted to decipher the roles, molecular mechanisms and regulation of this enzyme. This revealed that MuRF1 is an important player in the skeletal muscle atrophy process occurring during catabolic states, making MuRF1 a prime candidate for pharmacological treatments against muscle wasting. Indeed, muscle wasting is an associated event of several diseases (e.g., cancer, sepsis, diabetes, renal failure, etc.) and negatively impacts the prognosis of patients, which has stimulated the search for MuRF1 inhibitory molecules. However, studies on MuRF1 cardiac functions revealed that MuRF1 is also cardioprotective, revealing a yin and yang role of MuRF1, being detrimental in skeletal muscle and beneficial in the heart. This review discusses data obtained on MuRF1, both in skeletal and cardiac muscles, over the past 20 years, regarding the structure, the regulation, the location and the different functions identified, and the first inhibitors reported, and aim to draw the picture of what is known about MuRF1. The review also discusses important MuRF1 characteristics to consider for the design of future drugs to maintain skeletal muscle mass in patients with different pathologies.

Rise of TRIM8: A Molecule of Duality

The human tripartite motif containing protein 8 (TRIM8), a member of TRIM family proteins, is known to play a dual role as both tumor suppressor and oncogene, and to function at the crosstalk of cancer and innate immunity. In this review, in addition to accumulating recent corroborations that endorse this dual character of TRIM8, we appraise the game-changing capacity of TRIM8 under stress conditions against the backdrop of cell proliferation, apoptosis, and cancer, and also highlight the duality of TRIM8 in multiple contexts like cellular localization, stress-induced conditions, and E3 ubiquitin ligase activity. Finally, we discuss the emerging role of TRIM8 during bipolar spindle formation and mitotic progression, and its growing sphere of influence across multiple human cancers and pathologies, and suggest TRIM8-linked axes that can be modulated further for anti-cancer therapeutics development.

Focal segmental glomerulosclerosis and mild intellectual disability in a patient with a novel de novo truncating TRIM8 mutation

Mutations in the TRIM8 gene have been described in patients with severe developmental delay, intellectual disability and epilepsy. Only six patients have been described to date. All the previous mutations were truncating variants clustered in the C-terminus of the protein. A previous patient with TRIM8-related epileptic encephalopathy was reported to have nephrotic syndrome. Here we describe the clinical, radiological and histological features of an 8-year-old male patient with a TRIM8 mutation who, in contrast to previous patients, had only mild intellectual disability and well-controlled epilepsy. The patient was found to have proteinuria at 2 years of age. Renal biopsy findings were suggestive of focal segmental glomerulosclerosis. His kidney function declined and peritoneal dialysis was started at 5 years of age. He underwent renal transplant at 7 years of age. Trio-based whole genome sequencing identified a novel de novo heterozygous frameshift mutation in TRIM8 (NM_030912.2) c.1198_1220del, p.(Tyr400ArgfsTer2). This patient is further evidence that TRIM8 mutations cause a syndrome with both neurological and renal features. Our findings suggest the spectrum of TRIM8-related disease may be wider than previously thought with the possibility of milder neurodevelopmental problems and/or a more severe, progressive renal phenotype. We highlight the need for proteinuria screening in patients with TRIM8 mutations.

MicroRNA-665-3p attenuates oxygen-glucose deprivation-evoked microglial cell apoptosis and inflammatory response by inhibiting NF-κB signaling via targeting TRIM8

Microglial inflammation induced by ischemic stroke aggravates brain damage. MicroRNAs (miRNAs) have emerged as pivotal regulators in ischemic stroke-induced inflammation in microglial cells. miR-665-3p has been reported as a critical inflammation-associated miRNA. However, whether miR-665-3p participates in regulating microglial inflammation during ischemic stroke is underdetermined. This study investigated the potential role of miR-665-3p in stroke-induced inflammation in microglial cells using a cellular model of oxygen-glucose deprivation (OGD)-stimulated microglial cells in vitro. We found that miR-665-3p expression was decreased in microglial cells exposed to OGD treatment. Functional experiments demonstrated that the overexpression of miR-665-3p attenuated OGD-induced apoptosis and inflammation in microglial cells. Notably, tripartite motif 8 (TRIM8) was identified as a target gene of miR-665-3p. TRIM8 expression was induced by OGD treatment in microglial cells and the knockdown of TRIM8 protected microglial cells from OGD -induced cytotoxicity and inflammation. Moreover, TRIM8 knockdown or miR-665-3p overexpression blocked OGD-induced activation of nuclear factor (NF)-κB signaling in microglial cells. In addition, TRIM8 overexpression partially reversed the miR-665-3p overexpression-mediated inhibitory effect on OGD-induced inflammation in microglial cells. Taken together, these results indicate that miR-665-3p up-regulation protects microglial cells from OGD-induced apoptosis and inflammatory response by targeting TRIM8 to inhibit NF-κB signaling.

Suppression of TRIM8 by microRNA-182-5p restricts tumor necrosis factor-α-induced proliferation and migration of airway smooth muscle cells through inactivation of NF-Κb

MicroRNAs (miRNAs) have emerged as critical modulators involved in the regulation of airway remodeling in asthma. MicroRNA-182-5p (miR-182-5p) has been reported as a key miRNA in regulating the proliferation and migration of various cell types, and its dysfunction contributes is implicated in a wide range of pathological processes. Yet, it remains unknown whether miR-182-5p modulates the proliferation and migration of airway smooth muscle (ASM) cells during asthma. In the present study, we aimed to determine the potential role of miR-182-5p in regulating the proliferation and migration of ASM cells induced by tumor necrosis factor (TNF)-α in vitro. We found that TNF-α stimulation markedly reduced miR-182-5p expression in ASM cells. Gain-of-function experiments showed that miR-182-5p upregulation suppressed the proliferation and migration of ASM cells induced by TNF-α. By contrast, miR-182-5p inhibition had the opposite effect. Notably, tripartite motif 8 (TRIM8) was identified as a target gene of miR-182-5p. TRIM8 expression was induced by TNF-α stimulation, and TRIM8 knockdown markedly impeded TNF-α-induced ASM cell proliferation and migration. Moreover, miR-182-5p overexpression or TRIM8 knockdown significantly downregulated the activation of nuclear factor-κB (NF-κB) induced by TNF-α. However, TRIM8 restoration partially reversed the miR-182-5p-mediated inhibitory effect on TNF-α-induced ASM cell proliferation and migration. In conclusion, our study indicates that miR-182-5p restricts TNF-α-induced ASM cell proliferation and migration through downregulation of NF-κB activation via targeting TRIM8. The results of our study highlight the potential importance of the miR-182-5p/TRIM8/NF-κB axis in the airway remodeling of asthma.

Tripartite-motif family genes associated with cancer stem cells affect tumor progression and can assist in the clinical prognosis of kidney renal clear cell carcinoma

Ubiquitination is presently a hot topic in the field of oncology. The tripartite-motif (TRIM) family of proteins represents one of the largest classes of putative single protein RING-finger E3 ubiquitin ligases, which play an essential role in the ubiquitination of proteins in the body. At the same time, research related to cancer stem cells (CSCs) is increasing in popularity in the field of oncology. CSCs are potentially chemically resistant and can be selectively enriched in patients receiving chemotherapy, ultimately leading to adverse outcomes, such as treatment failure and cancer recurrence. There is a close relationship between multiple TRIM family genes and CSCs. Accumulating evidence suggests that TRIM family proteins are expressed in diverse human cancers and act as regulators of oncoproteins or tumor suppressor proteins. In this study, we used biological information to explore the potential function of TRIM family genes related to CSCs in the development of pan-cancer. Kidney renal clear cell carcinoma (KIRC) is one of the deadliest malignant tumors in the world. Owing to its complex molecular and cellular heterogeneity, the effectiveness of existing KIRC-related risk prediction models is not satisfactory at present. Therefore, we focused on the potential role of these TRIM family genes in KIRC and used seven TRIM family genes to establish a prognostic risk model. This model includes TRIM16, TRIM32, TRIM24, TRIM8, TRIM27, PML, and TRIM11. In conclusion, this study provides further insight into the prognosis of KIRC, which may guide treatment.

TRIM8 is required for virus-induced IFN response in human plasmacytoid dendritic cells

Plasmacytoid dendritic cells (pDCs) play a crucial role in antiviral innate immunity through their unique capacity to produce large amounts of type I interferons (IFNs) upon viral detection. Tripartite motif (TRIM) proteins have recently come forth as important modulators of innate signaling, but their involvement in pDCs has not been investigated. Here, we performed a rationally streamlined small interfering RNA (siRNA)-based screen of TRIM proteins in human primary pDCs to identify those that are critical for the IFN response. Among candidate hits, TRIM8 emerged as an essential regulator of IFN regulatory factor 7 (IRF7) function. Mechanistically, TRIM8 protects phosphorylated IRF7 (pIRF7) from proteasomal degradation in an E3 ubiquitin ligase-independent manner by preventing its recognition by the peptidyl-prolyl isomerase Pin1. Our findings uncover a previously unknown regulatory mechanism of type I IFN production in pDCs by which TRIM8 and Pin1 oppositely regulate the stability of pIRF7.

Tripartite Motif 8 Deficiency Relieves Hepatic Ischaemia/reperfusion Injury via TAK1-dependent Signalling Pathways

Tripartite motif (Trim) 8 is an E3 ubiquitin ligase, interacting with and ubiquitinating diverse substrates, and is closely involved in innate immunity. However, the function of Trim8 in hepatic ischaemia/reperfusion (I/R) injury remains largely unknown. The aim of this study is to explore the role of Trim8 in hepatic I/R injury. Trim8 gene knockout mice and primary hepatocytes were used to construct hepatic I/R models. The effect of Trim8 on hepatic I/R injury was analysed via pathological and molecular analyses. The results indicated that Trim8 was significantly upregulated in liver of mice subjected to hepatic I/R injury. Trim8 knockout relieved hepatocyte injury triggered by I/R. Silencing of Trim8 expression alleviated hepatic inflammation responses and inhibited apoptosis in vitro and in vivo. Mechanistically, our study suggests that Trim8 deficiency may elicit hepatic protective effects by inhibiting the activation of transforming growth factor β-activated kinase 1 (TAK1)-p38/JNK signalling pathways. TAK1 was required for Trim8 function in hepatic I/R injury as TAK1 activation abolished Trim8 function in vitro. In conclusion, our study demonstrates that Trim8 deficiency plays a protective role in hepatic I/R injury by inhibiting the activation of TAK1-dependent signalling pathways.

Targeting Chemoresistant Tumors: Could TRIM Proteins-p53 Axis Be a Possible Answer?

Chemosensitivity is a crucial feature for all tumours so that they can be successfully treated, but the huge heterogeneity of these diseases, to be intended both inter- and intra-tumour, makes it a hard-to-win battle. Indeed, this genotypic and phenotypic variety, together with the adaptability of tumours, results in a plethora of chemoresistance acquisition mechanisms strongly affecting the effectiveness of treatments at different levels. Tripartite motif (TRIM) proteins are shown to be involved in some of these mechanisms thanks to their E3-ubiquitin ligase activity, but also to other activities they can exert in several cellular pathways. Undoubtedly, the ability to regulate the stability and activity of the p53 tumour suppressor protein, shared by many of the TRIMs, represents the preeminent link between this protein family and chemoresistance. Indeed, they can modulate p53 degradation, localization and subset of transactivated target genes, shifting the cellular response towards a cytoprotective or cytotoxic reaction to whatever damage induced by therapy, sometimes in a cellular-dependent way. The involvement in other chemoresistance acquisition mechanisms, independent by p53, is known, affecting pivotal processes like PI3K/Akt/NF-κB signalling transduction or Wnt/beta catenin pathway, to name a few. Hence, the inhibition or the enhancement of TRIM proteins functionality could be worth investigating to better understand chemoresistance and as a strategy to increase effectiveness of anticancer therapies.

The Mutant p53-Targeting Compound APR-246 Induces ROS-Modulating Genes in Breast Cancer Cells

TP53 is the most frequently mutated gene in human cancer and thus an attractive target for novel cancer therapy. Several compounds that can reactive mutant p53 protein have been identified. APR-246 is currently being tested in a phase II clinical trial in high-grade serous ovarian cancer. We have used RNA-seq analysis to study the effects of APR-246 on gene expression in human breast cancer cell lines. Although the effect of APR-246 on gene expression was largely cell line dependent, six genes were upregulated across all three cell lines studied, i.e., TRIM16, SLC7A11, TXNRD1, SRXN1, LOC344887, and SLC7A11-AS1. We did not detect upregulation of canonical p53 target genes such as CDKN1A (p21), 14-3-3σ, BBC3 (PUMA), and PMAIP1 (NOXA) by RNA-seq, but these genes were induced according to analysis by qPCR. Gene ontology analysis showed that APR-246 induced changes in pathways such as response to oxidative stress, gene expression, cell proliferation, response to nitrosative stress, and the glutathione biosynthesis process. Our results are consistent with the dual action of APR-246, i.e., reactivation of mutant p53 and modulation of redox activity. SLC7A11, TRIM16, TXNRD1, and SRXN1 are potential new pharmacodynamic biomarkers for assessing the response to APR-246 in both preclinical and clinical studies.