Many Faces of TRIM Proteins on the Road from Pluripotency to Neurogenesis

Trim47 prevents hematopoietic stem cell exhaustion during stress by regulating MAVS-mediated innate immune pathway

The maintenance of hematopoietic stem cell (HSC) functional integrity is essential for effective hematopoietic regeneration when suffering from injuries. Studies have shown that the innate immune pathways play crucial roles in the stress response of HSCs, whereas how to precisely modulate these pathways is not well characterized. Here, we identify the E3 ubiquitin ligase tripartite motif-containing 47 (Trim47) as a negative regulator of the mitochondrial antiviral-signaling protein (MAVS)-mediated innate immune pathway in HSCs. We find that Trim47 is predominantly enriched in HSCs, and its deficiency impairs the function and survival of HSCs after exposure to 5-flurouracil (5-FU) and irradiation (IR). Mechanistically, Trim47 impedes the excessive activation of the innate immune signaling and inflammatory response via K48-linked ubiquitination and degradation of MAVS. Collectively, our findings demonstrate a role of Trim47 in preventing stress-induced hematopoietic failure and thus provide a promising avenue for treatment of related diseases in the clinic.

Multi-Directional Mechanisms of Participation of the TRIM Gene Family in Response of Innate Immune System to Bacterial Infections

The multigene TRIM family is an important component of the innate immune system. For a long time, the main function of the genes belonging to this family was believed to be an antiviral defense of the host organism. The issue of their participation in the immune system response to bacterial invasion has been less studied. This review is the first comprehensive analysis of the mechanisms of functioning of the TRIM family genes in response to bacterial infections, which expands our knowledge about the role of TRIM in the innate immune system. When infected with different types of bacteria, individual TRIM proteins regulate inflammatory, interferon, and other responses of the immune system in the cells, and also affect autophagy and apoptosis. Functioning of TRIM proteins in response to bacterial infection, as well as viral infection, often includes ubiquitination and various protein-protein interactions with both bacterial proteins and host cell proteins. At the same time, some TRIM proteins, on the contrary, contribute to the infection development. Different members of the TRIM family possess similar mechanisms of response to viral and bacterial infection, and the final impact of these proteins could vary significantly. New data on the effect of TRIM proteins on bacterial infections make an important contribution to a more detailed understanding of the innate immune system functioning in animals and humans when interacting with pathogens. This data could also be used for the search of new targets for antibacterial defense.

Curcumol, a major terpenoid from Curcumae Rhizoma, attenuates human uterine leiomyoma cell development via the p38MAPK/NF-κB pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Uterine fibroids (UFs) are the most common benign tumors in women of reproductive age. Curcumae Rhizoma, the main essential oil component of which is curcumol, is widely used for the treatment of phymatosis in China due to its antitumor, anti-inflammatory, antithrombin, anti-tissue fibrosis and anti-oxygen pharmacological activities, but its potential for the treatment of UFs has not been evaluated.

AIM OF THE STUDY

This study aimed to investigate the effects and mechanisms of curcumol intervention in human uterine leiomyoma cells (UMCs).

MATERIALS AND METHODS

Putative targets of curcumol intervention in UFs were identified using network pharmacology strategies. Molecular docking was performed to assess the binding affinity of curcumol to core targets. A concentration gradient of curcumol (0, 50, 100, 200, 300, 400 and 500 μM) or RU-486 (mifepristone, 0, 10, 20, 40, 50, and 100 μM) was applied to UMCs, and cell viability was detected by the CCK-8 assay. Cell apoptosis and cell cycle were examined by flow cytometry, and cell migration was assessed by a wound-healing assay. Additionally, the mRNA and protein expression levels of critical pathway components were evaluated by RT‒PCR and western blotting. Finally, the actions of curcumol on different tumor cell lines were summarized.

RESULTS

Network pharmacology predicted 62 genes with roles in the treatment of UFs with curcumol, and MAPK14 (p38MAPK) displayed a higher interaction degree. GO enrichment and KEGG analyses revealed that the core genes were abundantly enriched in the MAPK signaling pathway. The molecular binding of curcumol to core targets was relatively stable. In UMCs, 200, 300 and 400 μM curcumol treatment for 24 h decreased cell viability compared with that in the control group, and the greatest effect was detected at 48 h and maintained until 72 h. Curcumol arrested cells in the G0/G1 phase and subsequently suppressed mitosis, promoted early apoptosis and reduced the degree of wound healing in a concentration-dependent manner in UMCs. Furthermore, 200 μM curcumol decreased the mRNA and protein expression of p38MAPK, the mRNA expression of NF-κB, and the protein expression of Ki-67 and increased the mRNA and protein expression of Caspase 9. Curcumol (300 and 400 μM) decreased the mRNA and protein expression of p38MAPK, NF-κB, and Ki-67 and increased the protein expression of Caspase 9 in UMCs. Curcumol was demonstrated to treat tumor cell lines, including breast cancer, ovarian cancer, lung cancer, gastric cancer, liver cancer and nasopharyngeal carcinoma, but its effects on benign tumors have not yet been reported.

CONCLUSION

Curcumol suppresses cell proliferation and cell migration while arresting the cell cycle in the G0/G1 phase and inducing cell apoptosis in UMCs via a mechanism related to p38MAPK/NF-κB pathway regulation. Curcumol may be a potential therapeutic and preventive agent in the treatment of benign tumors such as UFs.

Emerging Roles of TRIM Family Proteins in Gliomas Pathogenesis

Simple Summary

Gliomas remain challenging tumors due to their increased heterogeneity, complex molecular profile, and infiltrative phenotype that are often associated with a dismal prognosis. In a constant search for molecular changes and associated mechanisms, the TRIM protein family has emerged as an important area of investigation because of the regulation of vital cellular processes involved in brain pathophysiology that may possibly lead to brain tumor development. Herein, we discuss the diverse role of TRIM proteins in glioma progression, aiming to detect potential targets for future intervention.

Abstract

Gliomas encompass a vast category of CNS tumors affecting both adults and children. Treatment and diagnosis are often impeded due to intratumor heterogeneity and the aggressive nature of the more malignant forms. It is therefore essential to elucidate the molecular mechanisms and explore the intracellular signaling pathways underlying tumor pathology to provide more promising diagnostic, prognostic, and therapeutic tools for gliomas. The tripartite motif-containing (TRIM) superfamily of proteins plays a key role in many physiological cellular processes, including brain development and function. Emerging evidence supports the association of TRIMs with a wide variety of cancers, exhibiting both an oncogenic as well as a tumor suppressive role depending on cancer type. In this review, we provide evidence of the pivotal role of TRIM proteins in gliomagenesis and exploit their potential as prognostic biomarkers and therapeutic targets.

SANA: cross-species prediction of Gene Ontology GO annotations via topological network alignment

Topological network alignment aims to align two networks node-wise in order to maximize the observed common connection (edge) topology between them. The topological alignment of two protein-protein interaction (PPI) networks should thus expose protein pairs with similar interaction partners allowing, for example, the prediction of common Gene Ontology (GO) terms. Unfortunately, no network alignment algorithm based on topology alone has been able to achieve this aim, though those that include sequence similarity have seen some success. We argue that this failure of topology alone is due to the sparsity and incompleteness of the PPI network data of almost all species, which provides the network topology with a small signal-to-noise ratio that is effectively swamped when sequence information is added to the mix. Here we show that the weak signal can be detected using multiple stochastic samples of "good" topological network alignments, which allows us to observe regions of the two networks that are robustly aligned across multiple samples. The resulting network alignment frequency (NAF) strongly correlates with GO-based Resnik semantic similarity and enables the first successful cross-species predictions of GO terms based on topology-only network alignments. Our best predictions have an AUPR of about 0.4, which is competitive with state-of-the-art algorithms, even when there is no observable sequence similarity and no known homology relationship. While our results provide only a "proof of concept" on existing network data, we hypothesize that predicting GO terms from topology-only network alignments will become increasingly practical as the volume and quality of PPI network data increase.

The genetic architecture of structural left-right asymmetry of the human brain

Left-right hemispheric asymmetry is an important aspect of healthy brain organization for many functions including language, and it can be altered in cognitive and psychiatric disorders. No mechanism has yet been identified for establishing the human brain's left-right axis. We performed multivariate genome-wide association scanning of cortical regional surface area and thickness asymmetries, and subcortical volume asymmetries, using data from 32,256 participants from the UK Biobank. There were 21 significant loci associated with different aspects of brain asymmetry, with functional enrichment involving microtubule-related genes and embryonic brain expression. These findings are consistent with a known role of the cytoskeleton in left-right axis determination in other organs of invertebrates and frogs. Genetic variants associated with brain asymmetry overlapped with those associated with autism, educational attainment and schizophrenia. Comparably large datasets will likely be required in future studies, to replicate and further clarify the associations of microtubule-related genes with variation in brain asymmetry, behavioural and psychiatric traits.

TRIMming Down Hormone-Driven Cancers: The Biological Impact of TRIM Proteins on Tumor Development, Progression and Prognostication

The tripartite motif (TRIM) protein family is attracting increasing interest in oncology. As a protein family based on structure rather than function, a plethora of biological activities are described for TRIM proteins, which are implicated in multiple diseases including cancer. With hormone-driven cancers being among the leading causes of cancer-related death, TRIM proteins have been described to portrait tumor suppressive or oncogenic activities in these tumor types. This review describes the biological impact of TRIM proteins in relation to hormone receptor biology, as well as hormone-independent mechanisms that contribute to tumor cell biology in prostate, breast, ovarian and endometrial cancer. Furthermore, we point out common functions of TRIM proteins throughout the group of hormone-driven cancers. An improved understanding of the biological impact of TRIM proteins in cancer may pave the way for improved prognostication and novel therapeutics, ultimately improving cancer care for patients with hormone-driven cancers.

Human TRIM14 protects transgenic mice from influenza A viral infection without activation of other innate immunity pathways

TRIM14 is an important component of innate immunity that defends organism from various viruses. It was shown that TRIM14 restricted influenza A virus (IAV) infection in cell cultures in an interferon-independent manner. However, it remained unclear whether TRIM14 affects IAV reproduction and immune system responses upon IAV infection in vivo. In order to investigate the effects of TRIM14 at the organismal level we generated transgenic mice overexpressing human TRIM14 gene. We found that IAV reproduction was strongly inhibited in lungs of transgenic mice, resulting in the increased survival of transgenic animals. Strikingly, upon IAV infection, the transcription of genes encoding interferons, IL-6, IL-1β, and TNFα was notably weaker in lungs of transgenic animals than that in control mice, thus indicating the absence of significant induction of interferon and inflammatory responses. In spleen of transgenic mice, where TRIM14 was unexpectedly downregulated, upon IAV infection the transcription of genes encoding interferons was oppositely increased. Therefore, we demonstrated the key role of TRIM14 in anti-IAV protection in the model organism that is realized without noticeable activation of other innate immune system pathways.

TRIM28 functions as a negative regulator of aggresome formation

Selective recognition and elimination of misfolded polypeptides are crucial for protein homeostasis. When the ubiquitin-proteasome system is impaired, misfolded polypeptides tend to form small cytosolic aggregates and are transported to the aggresome and eventually eliminated by the autophagy pathway. Despite the importance of this process, the regulation of aggresome formation remains poorly understood. Here, we identify TRIM28/TIF1β/KAP1 (tripartite motif containing 28) as a negative regulator of aggresome formation. Direct interaction between TRIM28 and CTIF (cap binding complex dependent translation initiation factor) leads to inefficient aggresomal targeting of misfolded polypeptides. We also find that either treatment of cells with poly I:C or infection of the cells by influenza A viruses triggers the phosphorylation of TRIM28 at S473 in a way that depends on double-stranded RNA-activated protein kinase. The phosphorylation promotes association of TRIM28 with CTIF, inhibits aggresome formation, and consequently suppresses viral proliferation. Collectively, our data provide compelling evidence that TRIM28 is a negative regulator of aggresome formation.AbbreviationsBAG3: BCL2-associated athanogene 3; CTIF: CBC-dependent translation initiation factor; CED: CTIF-EEF1A1-DCTN1; DCTN1: dynactin subunit 1; EEF1A1: eukaryotic translation elongation factor 1 alpha 1; EIF2AK2: eukaryotic translation initiation factor 2 alpha kinase 2; HDAC6: histone deacetylase 6; IAV: influenza A virus; IP: immunoprecipitation; PLA: proximity ligation assay; polypeptidyl-puro: polypeptidyl-puromycin; qRT-PCR: quantitative reverse-transcription PCR; siRNA: small interfering RNA.

TRIM9 overexpression promotes uterine leiomyoma cell proliferation and inhibits cell apoptosis via NF-κB signaling pathway

AIMS

Uterine leiomyoma (UM) is the most common benign gynecological tumor and the leading indication for hysterectomy. Our study explored the roles of TRIM9 in leiomyoma formation and investigated the underlying molecular mechanisms.

MATERIAL AND METHODS

The relationship between TRIM9 expression and fibroids formation was deciphered from the GEO database after bioinformatics analysis and identified by qPCR in human leiomyoma tissues. Both TRIM9 mRNA and protein expression were further detected in primary cultured uterine leiomyoma cells (UMC). The tumorigenesis potentials of TRIM9 in cell proliferation, cell cycle, cell apoptosis; cyclin D1, survivin and cleaved-caspase 3 protein expressions in primary UMC with TRIM9 overexpression (UMC-oeTRIM9); and uterine smooth muscle cells (SMC) with TRIM9 knockdown (SMC-siTRIM9) were evaluated in vitro. NF-κB p65 and its phosphorylation were further examined by western blotting, and rescue experiments on cell proliferation, cell cycle and cell apoptosis were conducted.

KEY FINDINGS

TRIM9 showed higher expression in UM tissue and UMC compared with normal myometrium. The overexpression of TRIM9 in UMC notably promoted UM growth via enhancement of cell proliferation, reduction of cell apoptosis, and regulation of cyclin D1, survivin, cleaved-caspase 3, and nuclear NF-κB expression, which were reversed in SMC-siTRIM9 and PDTC (an NF-κB inhibitor) intervention in UMC-oeTRIM9.

SIGNIFICANCE

To our knowledge, this was the first study demonstrating the roles of TRIM9 in cell growth progression of UM development. TRIM9 may be a potential therapeutic target for UM, by promoting leiomyoma cell proliferation and reducing cell apoptosis via activation of the NF-κB pathway.