Trim47 is a critical regulator of cerebral ischemia-reperfusion injury through regulating apoptosis and inflammation

TRIM47-CDO1 axis dictates hepatocellular carcinoma progression by modulating ferroptotic cell death through the ubiquitin‒proteasome system

Hepatocellular carcinoma (HCC) is the predominant form of liver cancer, characterized by high morbidity and mortality rates, as well as unfavorable treatment outcomes. Tripartite motif-containing protein 47 (TRIM47) has been implicated in various diseases including tumor progression with the activity of E3 ubiquitin ligase. However, the precise regulatory mechanisms underlying the involvement of TRIM47 in HCC remain largely unexplored. Here, we provide evidence that TRIM47 exhibits heightened expression in tumor tissues, and its expression is in intimate association with clinical staging and patient prognosis. TRIM47 promotes HCC proliferation, migration, and invasion as an oncogene by in vitro gain- and loss-of-function experiments. TRIM47 knockdown results in HCC ferroptosis induction, primarily through CDO1 involvement to regulate GSH synthesis. Subsequent experiments confirm the interaction between TRIM47 and CDO1 dependent on B30.2 domain, wherein TRIM47 facilitates K48-linked ubiquitination, leading to a decrease in CDO1 protein abundance in HCC. Furthermore, CDO1 is able to counteract the promotional effect of TRIM47 on HCC biological functions. Overall, our research provides novel insight into the mechanism of TRIM47 in CDO1-mediated ferroptosis in HCC cells, highlighting its value as a potential target candidate for HCC therapeutic approaches.

RNA Sequencing Analyses Reveal the Potential Anti-Inflammatory Mechanisms of Acacetin Against ODG/R Injuries in Microglia

Background

Acacetin is a natural flavonoid known for its anti-tumor, antioxidant, and anti-inflammatory properties. Our previous studies have shown its protective effects against cerebral ischemia-reperfusion injury (IRI), but the underlying molecular mechanisms remain unclear.

Purpose

The study delves into acacetin's mechanism in mitigating cerebral IRI, with a focus on transcriptomic insights.

Methods

We established the oxygen-glucose deprivation/re-oxygenation (OGD/R) model in BV2 microglia, treating them with 10μM acacetin. Then we assessed cell proliferation using CCK-8 and measured Lactate Dehydrogenase (LDH) release. High-throughput RNA sequencing (RNA-seq) underpinned the analysis of differentially expressed genes (DEGs) and long non-coding RNAs (lncRNAs), functional enrichment, and alternative splicing events (ASEs), validated by reverse transcription-quantitative polymerase chain reaction (RT-qPCR).

Results

OGD/R injury significantly impaired cell proliferation and increased LDH release, effects mitigated by acacetin. RNA-seq identified 2148 upregulated and 2135 downregulated DEGs post-OGD/R. In contrast, the acacetin-treated group showed 248 upregulated and 240 downregulated DEGs compared to the OGD/R group. All DEGs were enriched in both Gene Ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. Overlapping analysis indicated that acacetin treatment reversed the expression of 203 genes affected by OGD/R, including inflammation-related genes such as Isg15, Fcgr1, Il1b, and Parp12. Moreover, the oxidative stress-related gene, Mt2, was downregulated post-OGD/R but upregulated following acacetin treatment. We further found that OGD/R and acacetin treatment could modulate gene splicing events, impacting cell apoptosis or inflammatory responses, such as the A3SS splicing event in the Trim47 gene. RNA-seq also highlighted differential expression of numerous lncRNAs, particularly the upregulation of lncRNA Rmrp and Terc post-OGD/R and their subsequent downregulation post-acacetin treatment. These lncRNAs might regulate cell proliferation through mediating target gene expressions. RT-qPCR validation confirmed these findings.

Conclusion

Significant upregulation of genes and ASEs linked to oxidative stress and inflammatory response is observed in cerebral IRI. Acacetin intervention reverses these effects, highlighting its mechanism in alleviating the injury by modulating gene expression and splicing events.

Synergistic effect of chrysin and kaempferol in ameliorating Cerebral Ischemic Reperfusion injury in rat by controlling expression of proinflammatory mediators NF-κB and STAT3

OBJECTIVES

The two flavonoids kaempferol and chrysin are known to possess anti-inflammatory and antioxidant activities. In addition, these two flavonoids were reported to display synergistic effects against inflammation. The present study aims to provide an analysis of the combined effects of kaempferol and chrysin on ischemic rat brain induced by endothelin-1.

METHODS

The neurological deficit score and infarct area of the brain were determined post drug treatment. Histopathological sections displayed the morphological changes in the brain tissue. The brain tissues were processed for assessing the antioxidant and anti-inflammatory activity by measuring superoxide dismutase activity, catalase activity, level of reduced glutathione, brain malondialdehyde, and amount of calcium. The expression level of inflammatory molecules was analyzed by western blotting and immunohistochemistry.

RESULTS

The infarct area, neurological score and NF-κB and STAT3 expression levels were significantly reduced.

DISCUSSION

The analysis of neuroprotective synergistic activity of kaempferol and chrysin indicated the therapeutic potential of the combination in alleviating cerebral ischemia by controlling expression of proinflammatory mediators.

TRIM47 promotes HDM-induced bronchial epithelial pyroptosis by regulating NEMO ubiquitination to activate NF-κB/NLRP3 signaling

Asthma is an inflammatory disease. Airway epithelial cell pyroptosis and cytokine secretion promote asthma progression. Tripartite motif 47 (TRIM47) belongs to the E3 ubiquitin ligase family and is associated with apoptosis and inflammation in a range of diseases. However, the role of TRIM47 in asthma has not been explored. In this study, the human bronchial epithelial cell line BEAS-2B was treated with house dust mite (HDM) and TRIM47 expression was detected by RT-qPCR and Western blot. After transfection with TRIM47 interfering and overexpressing plasmids, the synthesis and secretion of cytokines, as well as pyroptosis-related indicators, were examined. Nuclear factor kappa-B (NF-κB) pathway proteins and nod-like receptor protein 3 (NLRP3) inflammasome were measured to explore the mechanism of TRIM47 action. In addition, the effect of TRIM47 on the level of NF-κB essential modulator (NEMO) ubiquitination was detected by an immunoprecipitation assay. The results showed that TRIM47 was upregulated in HDM-induced BEAS-2B cells and that TRIM47 mediated HDM-induced BEAS-2B cell pyroptosis and cytokine secretion. Mechanistically, TRIM47 promoted the K63-linked ubiquitination of NEMO and facilitated NF-κB/NLRP3 pathway activation. In conclusion, TRIM47 may promote cytokine secretion mediating inflammation and pyroptosis in bronchial epithelial cells by activating the NF-κB/NLRP3 pathway. Therefore, TRIM47 may be a potential therapeutic target for HDM-induced asthma.

Ubiquitous regulation of cerebrovascular diseases by ubiquitin-modifying enzymes

Cerebrovascular diseases (CVDs) are a major threat to global health. Elucidation of the molecular mechanisms underlying the pathology of CVDs is critical for the development of efficacious preventative and therapeutic approaches. Accumulating studies have highlighted the significance of ubiquitin-modifying enzymes (UMEs) in the regulation of CVDs. UMEs are a group of enzymes that orchestrate ubiquitination, a post-translational modification tightly involved in CVDs. Functionally, UMEs regulate multiple pathological processes in ischemic and hemorrhagic stroke, moyamoya disease, and atherosclerosis. Considering the important roles of UMEs in CVDs, they may become novel druggable targets for these diseases. Besides, techniques applying UMEs, such as proteolysis-targeting chimera and deubiquitinase-targeting chimera, may also revolutionize the therapy of CVDs in the future.

Dietary Supplementation with Nervonic Acid Ameliorates Cerebral Ischemia-Reperfusion Injury by Modulating of Gut Microbiota Composition-Fecal Metabolites Interaction

SCOPE

Cerebral ischemia-reperfusion (IR) injury stands as a prominent global contributor to disability and mortality. Nervonic acid (NA), a bioactive elongated monounsaturated fatty acid, holds pivotal significance in human physiological well-being. This research aims to explore the prophylactic effects and fundamental mechanisms of NA in a rat model of cerebral IR injury.

METHODS AND RESULTS

Through the induction of middle cerebral artery occlusion, this study establishes a rat model of cerebral IR injury and comprehensively assesses the pharmacodynamic impacts of NA pretreatment. This evaluation involves behavioral analyses, histopathological examinations, and quantification of serum markers. Detailed mechanisms of nervonic acid's prophylactic effects are revealed through fecal metabolomics and 16S rRNA sequencing analyses. Our findings robustly support nervonic acid's capacity to ameliorate neurological impairments in rats afflicted with cerebral IR injury. Beyond its neurological benefits, NA demonstrates its potential by rectifying metabolic perturbations across diverse pathways, particularly those pertinent to unsaturated fatty acid metabolism. Additionally, NA emerges as a modulator of gut microbiota composition, notably by selectively enhancing vital genera like Lactobacillus.

CONCLUSION

These comprehensive findings highlight the potential of incorporating NA as a functional component in dietary interventions aimed at targeting cerebral IR injury.

It's a TRIM-endous view from the top: the varied roles of TRIpartite Motif proteins in brain development and disease

The tripartite motif (TRIM) protein family members have been implicated in a multitude of physiologies and pathologies in different tissues. With diverse functions in cellular processes including regulation of signaling pathways, protein degradation, and transcriptional control, the impact of TRIM dysregulation can be multifaceted and complex. Here, we focus on the cellular and molecular roles of TRIMs identified in the brain in the context of a selection of pathologies including cancer and neurodegeneration. By examining each disease in parallel with described roles in brain development, we aim to highlight fundamental common mechanisms employed by TRIM proteins and identify opportunities for therapeutic intervention.

The MEF2A transcription factor interactome in cardiomyocytes

Transcriptional regulators encoded by the Myocyte Enhancer Factor 2 (MEF2) gene family play a fundamental role in cardiac development, homeostasis and pathology. Previous studies indicate that MEF2A protein-protein interactions serve as a network hub in several cardiomyocyte cellular processes. Based on the idea that interactions with regulatory protein partners underly the diverse roles of MEF2A in cardiomyocyte gene expression, we undertook a systematic unbiased screen of the MEF2A protein interactome in primary cardiomyocytes using an affinity purification-based quantitative mass spectrometry approach. Bioinformatic processing of the MEF2A interactome revealed protein networks involved in the regulation of programmed cell death, inflammatory responses, actin dynamics and stress signaling in primary cardiomyocytes. Further biochemical and functional confirmation of specific protein-protein interactions documented a dynamic interaction between MEF2A and STAT3 proteins. Integration of transcriptome level data from MEF2A and STAT3-depleted cardiomyocytes reveals that the balance between MEF2A and STAT3 activity exerts a level of executive control over the inflammatory response and cardiomyocyte cell survival and experimentally ameliorates Phenylephrine induced cardiomyocyte hypertrophy. Lastly, we identified several MEF2A/STAT3 co-regulated genes, including the MMP9 gene. Herein, we document the cardiomyocyte MEF2A interactome, which furthers our understanding of protein networks involved in the hierarchical control of normal and pathophysiological cardiomyocyte gene expression in the mammalian heart.

Tripartite Motif Protein Family in Central Nervous System Diseases

Tripartite motif (TRIM) protein superfamily is a group of E3 ubiquitin ligases characterized by the conserved RING domain, the B-box domain, and the coiled-coil domain (RBCC). It is widely involved in various physiological and pathological processes, such as intracellular signal transduction, cell cycle regulation, oncogenesis, and innate immune response. Central nervous system (CNS) diseases are composed of encephalopathy and spinal cord diseases, which have a high disability and mortality rate. Patients are often unable to take care of themselves and their life quality can be seriously declined. Initially, the function research of TRIM proteins mainly focused on cancer. However, in recent years, accumulating attention is paid to the roles they play in CNS diseases. In this review, we integrate the reported roles of TRIM proteins in the pathological process of CNS diseases and related signaling pathways, hoping to provide theoretical bases for further research in treating CNS diseases targeting TRIM proteins. TRIM proteins participated in CNS diseases. TRIM protein family is characterized by a highly conserved RBCC domain, referring to the RING domain, the B-box domain, and the coiled-coil domain. Recent research has discovered the relations between TRIM proteins and various CNS diseases, especially Alzheimer's disease, Parkinson's disease, and ischemic stroke.

Downregulation of TNFAIP1 alleviates OGD/R‑induced neuronal damage by suppressing Nrf2/GPX4‑mediated ferroptosis

TNFα-induced protein 1 (TNFAIP1) serve a role in neurovascular disease. However, the potential role and molecular mechanism of TNFAIP1 in cerebral ischemia-reperfusion (I/R) remains elusive. In the present study, reverse transcription-quantitative PCR and western blotting were used to assess TNFAIP1 mRNA and protein expression levels in PC12 cells. Furthermore, using Cell Counting Kit-8, flow cytometry and western blotting, cell viability and apoptosis were evaluated. Oxidative stress was evaluated using DCFH-DA staining and ELISA was used for assessment of inflammatory factors. Expression of components in the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway and ferroptosis were assessed using western blotting analysis and an iron assay kit. TNFAIP1 expression was significantly upregulated in oxygen glucose deprivation and reperfusion (OGD/R)-injured PC12 cells. However, knocking down TNFAIP1 expression restored PC12 cell viability and decreased apoptosis following OGD/R-challenge. Furthermore, TNFAIP1 silencing significantly suppressed OGD/R-induced oxidative stress and inflammatory damage in PC12 cells. TNFAIP1 knockdown inhibited ferroptosis via activation of the Nrf2 signaling pathway in OGD/R-injured PC12 cells. Erastin treatment reversed the beneficial effects of TNFAIP1 knockdown on PC12 cell viability, apoptosis alleviation, oxidative stress and inflammation following OGD/R treatment. These results suggested that TNFAIP1 knockdown could alleviate OGD/R-induced neuronal cell damage by suppressing Nrf2-mediated ferroptosis, which might lay the foundation for the investigation of targeted-therapy for cerebral I/R injury in clinic.

Synaptic proteomics reveal distinct molecular signatures of cognitive change and C9ORF72 repeat expansion in the human ALS cortex

Increasing evidence suggests synaptic dysfunction is a central and possibly triggering factor in Amyotrophic Lateral Sclerosis (ALS). Despite this, we still know very little about the molecular profile of an ALS synapse. To address this gap, we designed a synaptic proteomics experiment to perform an unbiased assessment of the synaptic proteome in the ALS brain. We isolated synaptoneurosomes from fresh-frozen post-mortem human cortex (11 controls and 18 ALS) and stratified the ALS group based on cognitive profile (Edinburgh Cognitive and Behavioural ALS Screen (ECAS score)) and presence of a C9ORF72 hexanucleotide repeat expansion (C9ORF72-RE). This allowed us to assess regional differences and the impact of phenotype and genotype on the synaptic proteome, using Tandem Mass Tagging-based proteomics. We identified over 6000 proteins in our synaptoneurosomes and using robust bioinformatics analysis we validated the strong enrichment of synapses. We found more than 30 ALS-associated proteins in synaptoneurosomes, including TDP-43, FUS, SOD1 and C9ORF72. We identified almost 500 proteins with altered expression levels in ALS, with region-specific changes highlighting proteins and pathways with intriguing links to neurophysiology and pathology. Stratifying the ALS cohort by cognitive status revealed almost 150 specific alterations in cognitively impaired ALS synaptic preparations. Stratifying by C9ORF72-RE status revealed 330 protein alterations in the C9ORF72-RE +ve group, with KEGG pathway analysis highlighting strong enrichment for postsynaptic dysfunction, related to glutamatergic receptor signalling. We have validated some of these changes by western blot and at a single synapse level using array tomography imaging. In summary, we have generated the first unbiased map of the human ALS synaptic proteome, revealing novel insight into this key compartment in ALS pathophysiology and highlighting the influence of cognitive decline and C9ORF72-RE on synaptic composition.

TRIM47 is a novel endothelial activation factor that aggravates lipopolysaccharide-induced acute lung injury in mice via K63-linked ubiquitination of TRAF2

Endothelial activation plays an essential role in the pathogenesis of sepsis-induced acute lung injury, however, the detailed regulatory mechanisms remain largely unknown. Here, we reported that TRIM47, an E3 ubiquitin ligase of the tripartite motif-containing protein family, was highly expressed in vascular endothelial cells. TRIM47-deficient mice were effectively resistant to lipopolysaccharide (LPS)-induced acute lung injury and death by attenuating pulmonary inflammation. TRIM47 was upregulated during TNFα-induced endothelial activation in vitro. Knockdown of TRIM47 in endothelial cells inhibited the transcription of multiple pro-inflammatory cytokines, reduced monocyte adhesion and the expression of adhesion molecules, and suppressed the secretion of IL-1β and IL-6 in endothelial cells. By contrast, overexpression of TRIM47 promoted inflammatory response and monocyte adhesion upon TNFα stimulation. In addition, TRIM47 was able to activate the NF-κB and MAPK signaling pathways during endothelial activation. Furthermore, our experiments revealed that TRIM47 resulted in endothelial activation by promoting the K63-linked ubiquitination of TRAF2, a key component of the TNFα signaling pathway. Taken together, our studies demonstrated that TRIM47 as a novel activator of endothelial cells, promoted LPS-induced pulmonary inflammation and acute lung injury through potentiating the K63-linked ubiquitination of TRAF2, which in turn activates NF-κB and MAPK signaling pathways to trigger an inflammatory response in endothelial cells.

Gomisin J attenuates cerebral ischemia/reperfusion injury by inducing anti-apoptotic, anti-inflammatory, and antioxidant effects in rats

Ischemic stroke is one of the leading causes of morbidity and mortality in humans. Cerebral ischemia-reperfusion (CIR) injury serves as a leading cause of stroke. Schisandra chinensis is a well-known Chinese traditional medicine. In this study, we explored the role of Gomisin J (GJ), a compound of S. chinensis, in CIR using a middle cerebral artery occlusion/reperfusion rat model and the possible mechanisms. We identified that GJ reduced neurological scores, cerebral infarction, and water content in the I/R rat brain. Importantly, GJ rescued I/R treatment-reduced neuron survival in the hippocampus, inhibited apoptosis of ischemic tissues in I/R rats, increased B-cell lymphoma-extra-large (Bcl-XL) expression, and reduced the levels of cleaved caspase-3, Bax, cyclooxygenase-2, nuclear factor kappa-B, and nitric oxide in I/R rat brain tissues. Furthermore, GJ treatment enhanced nuclear factor E2 related factor 2 (Nrf2) translocation, heme oxygenase-1 (HO-1) expression, superoxide dismutase and glutathione peroxidase activities, and glutathione level. Overall, GJ treatment GJ attenuates CIR injury by inducing anti-apoptotic, antioxidant, and anti-inflammatory effects in vivo.

Chrysin, which targets PLAU, protects PC12 cells from OGD/R-stimulated damage through repressing the NF-κB signaling pathway

Cerebral ischemia reperfusion injury (CIRI) is a great challenge for the patients with brain ischemia, but its pathophysiological mechanism has not been clearly explored. This study aims to decipher the effect of chrysin and plasminogen activator urokinase (PLAU) in CIRI. The immune-related genes were collected from the ImmPort website, and the differentially expressed genes were determined based on the Gene Expression Omnibus (GEO) database. PC12 cells were used to establish an ischemic stroke model under the condition of oxygen-glucose deprivation and reoxygenation (OGD/R). Small interfering RNA strategy was employed to knock down the PLAU expression of PC12 cells. The proliferation and apoptosis rates of PC12 cells treated by OGD/R or/and chrysin were detected with Cell Counting Kit 8 (CCK-8) and flow cytometry. The protein and mRNA expressions were measured using western blotting and quantitative reverse transcription polymerase chain reaction (qRT-PCR). PLAU was identified as a candidate for CIRI treatment and expressed at higher levels in CIRI tissues compared with that in normal controls. Chrysin was determined as a crucial agent that could decrease the expression of PLAU. Chrysin significantly promoted the cell proliferation, inhibited the protein levels of PLAU, p–NF–κB, and p-IKκB in PC12 cells after OGD/R. Silencing of PLAU strengthened the protective effect of chrysin on PC12 cells treated by OGD/R, including the improvement of cell viability and suppression of apoptosis. Chrysin inactivated the NF-κB pathway via targeting PLAU in OGD/R-stimulated PC12 cells. Chrysin prevented PC12 cells from OGD/R-stimulated damage via decreasing PLAU expression and inactivating the NF-κB signaling pathway.

TRIM45 causes neuronal damage by aggravating microglia-mediated neuroinflammation upon cerebral ischemia and reperfusion injury

Excessive and unresolved neuroinflammation is a key component of the pathological cascade in brain injuries such as ischemic stroke. Tripartite motif-containing 45 (TRIM45) is a ubiquitin E3 ligase involved in various critical biological processes. However, the role of TRIM45 in cerebral ischemia remains unknown. Here, we found that the TRIM45 protein was highly expressed in the peri-infarct areas of mice subjected to cerebral ischemia and reperfusion injury induced by middle cerebral artery occlusion. This study systemically evaluated the putative role of TRIM45 in the regulation of neuroinflammation during ischemic injury and the potential underlying mechanisms. We found that TRIM45 knockdown significantly decreased proinflammatory cytokine and chemokine production in primary cultured microglia challenged with oxygen-glucose deprivation and reoxygenation (OGD/R) treatment. Mechanistically, we demonstrated that TRIM45 constitutively interacted with TAB2 and consequently facilitated the Lys-63-linked polyubiquitination of TAB2, leading to the formation of the TAB1-TAK1-TAB2 complex and activation of TAK1, which was ultimately followed by activation of the nuclear factor-kappa B (NF-κB) signaling pathway. In an in vitro coculture Transwell system, downregulation of TRIM45 expression also inhibited the OGD/R-induced activation of microglia and alleviated neuronal apoptosis. More importantly, microglia-specific knockdown of TRIM45 in mice significantly reduced the infarct size, mitigated neurological deficit scores, and improved cognitive function after ischemic stroke. Taken together, our study reveals that the TRIM45-TAB2 axis is a crucial checkpoint that controls NF-κB signaling in microglia during cerebral ischemia and reperfusion injury. Therefore, targeting TRIM45 may be an attractive therapeutic strategy.

CHIP ameliorates cerebral ischemia-reperfusion injury by attenuating necroptosis and inflammation

Blood reperfusion of ischemic cerebral tissue may cause cerebral ischemia-reperfusion (CIR) injury. Necroptosis and inflammation have been demonstrated to be involved in the disease-related process of CIR injury. The E3 ubiquitin ligase carboxyl terminus of Hsp70-interacting protein (CHIP) can modulate multiple cellular signaling processes, including necroptosis and inflammation. Numerous studies have demonstrated the neuroprotective effects of CHIP on multiple central nervous system (CNS) diseases. However, the effects of CHIP on CIR injury have not been fully explored. We hypothesize that CHIP can exert neuroprotective effects by attenuating necroptosis and inflammation during CIR injury. In the present study, adult wild-type (WT) C57BL/6 mice and CHIP knock-in (KI) mice with a C57BL/6 background and CHIP overexpression in neural tissue underwent middle cerebral artery occlusion (MCAO) surgery to simulate CIR onset. Our data indicated that CHIP expression in the peri-infarct tissue was markedly increased after MCAO surgery. Compared with WT mice, CHIP KI mice significantly improved neurological deficit scores, decreased cerebral infarct volume, and attenuated brain edema and neuronal damage. Meanwhile, CHIP overexpression attenuated necroptosis and inflammation induced by MCAO surgery. These findings indicated that overexpression of CHIP might exert neuroprotective effects by attenuating necroptosis and inflammation during CIR injury, and increasing CHIP levels may be a potential strategy in cerebrovascular disease therapy.

Long non-coding RNA LOC366613 alleviates the cerebral ischemic injury via regulating the miR-532-5p/phosphatase and tensin homolog axis

Cerebral infarction (CI) has become a leading cause of death in China. Long non-coding RNAs (lncRNAs) are intensively involved in the progression of CI. Here, we aimed to investigate the effects of lncRNA LOC366613 (LOC366613) on cerebral I/R injury, as well as its possible mechanism. Transient middle cerebral artery occlusion (MCAO) was used to establish a mouse model of cerebral I/R, and the PC12 cell line was used to establish an in vitro oxygen-glucose deprivation (OGD) injury model. The MTT assay was used to determine cell viability, and qRT-PCR was used to determine RNA levels. Western blotting was conducted to detect protein expression levels. The TUNEL assay and flow cytometry were used to measure cell apoptosis, and 2,3,5-triphenyltetrazolium chloride (TTC) was used to determine cerebral infarct volume. Finally, RNA pull-down and luciferase activity assays were used to examine interactions between miR-532-5p and LOC366613, as well as between miR-532-5p and phosphatase and tensin homolog (PTEN). LOC366613 was overexpressed in patients with cerebral I/R injury. In PC12 cells, knockdown of LOC366613 reduced the apoptosis rate and lactic acid dehydrogenase (LDH) expression, while increasing cell viability. Moreover, miR-532-5p was shown to be a target of LOC366613, as predicted. Downregulation of miR-532-5p reversed the effects of LOC366613 knockdown on PC12 cell apoptosis, LDH release, and cell viability. Finally, PTEN was verified as a target of miR-532-5p. LOC366613 participates in cerebral I/R injury by regulating the miR-532-5p/PTEN axis, potentially providing a new CI treatment target.

Downregulation of tripartite motif protein 11 attenuates cardiomyocyte apoptosis after ischemia/reperfusion injury via DUSP1-JNK1/2

Currently, the prevention of ischemic diseases such as myocardial infarction associated with ischemia/reperfusion (I/R) injury remains to be a challenge. Thus, this study was designed to explore the effects of tripartite motif protein 11 (TRIM11) on cardiomyocytes I/R injury and its underlying mechanism. Cardiomyocytes AC16 were used to establish an I/R injury cell model. After TRIM11 downregulation in I/R cells, cell proliferation (0, 12, 24, and 48 h) and apoptosis at 48 h as well as the related molecular changes in oxidative stress‐related pathways was detected. Further, after the treatment of TRIM11 overexpression, SP600125, or DUSP1 overexpression, cell proliferation, apoptosis, and related genes were detected again. As per our findings, it was determined that TRIM11 was highly expressed in the cardiomyocytes AC16 after I/R injury. Downregulation of TRIM11 was determined to have significantly reduced I/R‐induced proliferation suppression and apoptosis. Besides, I/R‐activated c‐Jun N‐terminal kinase (JNK) signaling and cleaved caspase 3 and Bax expression were significantly inhibited by TRIM11 downregulation. In addition, the overexpression of TRIM11 significantly promoted apoptosis in AC16 cells, and JNK1/2 inhibition and DUSP1 overexpression potently counteracted the induction of TRIM11 overexpression in AC16 cells. These suggested that the downregulation of TRIM11 attenuates apoptosis in AC16 cells after I/R injury probably through the DUSP1‐JNK1/2 pathways.

Combination of tetrandrine and 3-n-butylphthalide protects against cerebral ischemia-reperfusion injury via ATF2/TLR4 pathway

OBJECTIVE

Cerebral infarction (CI) is the mayor reason of death in China. Reperfusion is the only immediate treatment for acute cerebral infarction. However, blood reperfusion recovery may cause ischemia-reperfusion (I/R) injuries. The purpose of this study was to investigate the effects of Tetrandrine (TTD) and 3-n-Butylphthalide (NBP) on cerebral I/R injury.

MATERIALS AND METHODS

I/R was used to establish CI model in vivo. TTD was performed to analyze cerebral infarction volume. OGD was applied to establish CI model in vitro. Flow cytometry and TUNEL assays were utilized to determine the cell death. ELISA was conducted to determine the release of cytokines. mRNA and protein expressions were detected using qRT-PCR and western blot.

RESULTS

We found that NBP + TTD treatment significantly reduced cerebral infarction volume and inhibited the death of neurons in vivo. Moreover, NBP + TTD treatment suppressed the apoptosis and inflammatory response of neurons in vitro. Additionally, NBP + TTD suppressed the expression of activator transcription factor 2 (ATF2). However, overexpression of ATF2 contributed to the degeneration of neurons. Moreover, ATF2 transcriptionally activated Toll-like receptor 4 (TLR4). NBP + TTD inactivated ATF2/TLR4 signaling.

CONCLUSIONS

Taken together, TTD combined with NBP protected against cerebral infarction by inhibiting the inflammatory response and neuronal cell apoptosis via inactivating ATF2/TLR4 signaling pathways. This may provide an alternative for I/R injury.

Aloperine protects against cerebral ischemia/reperfusion injury via activating the PI3K/AKT signaling pathway in rats

Cerebral ischemia is among the leading causes of death and long-term disability worldwide. The aim of the present study was to investigate the effects of aloperine (ALO) on cerebral ischemia/reperfusion (I/R) injury in rats and elucidate the possible underlying mechanisms. Therefore, a rat model of reversible middle cerebral artery occlusion (MCAO) was established to induce cerebral I/R injury. Following pretreatment with different doses of ALO, the histopathological changes in the brain tissue were evaluated by hematoxylin and eosin staining. The degree of cerebral infarction was determined using by 2,3,5-triphenyltetrazolium chloride staining. Additionally, the levels of oxidative stress- and inflammation-related factors were measured using commercially available kits. Cell apoptosis was assessed by TUNEL staining, while the expression levels of apoptosis- and PI3K/AKT signaling pathway-related proteins were determined by western blot analysis. The results demonstrated that ALO alleviated histopathological injury in the brain tissue and the area of cerebral infarction in a dose-dependent manner. Furthermore, significantly reduced levels of reactive oxygen species and malondialdehyde were observed in the ALO-treated rats post-MCAO/reperfusion, accompanied by increased levels of superoxide dismutase, catalase and glutathione. Consistently, treatment with ALO notably decreased the concentration of inflammatory factors, including TNF-α, IL-1β and IL-6, in a dose-dependent manner. In addition, ALO attenuated neuronal cell apoptosis, downregulated the expression of Bax and upregulated that of Bcl-2. I/R markedly reduced the expression levels of phosphorylated (p-)PI3K and p-AKT, which were dose-dependently restored by ALO intervention. Collectively, the aforementioned findings indicated that ALO could improve cerebral I/R injury and alleviate oxidative stress, inflammation and cell apoptosis via activating the PI3K/AKT signaling pathway, thus supporting the therapeutic potential of ALO against cerebral I/R injury in ischemic stroke.

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.

Upregulated Tripartite Motif 47 Could Facilitate Glioma Cell Proliferation and Metastasis as a Tumorigenesis Promoter

Introduction

Tripartite motif 47 (TRIM47) belongs to a category of the TRIM family. It takes part in cancer tumorigenesis, thus demonstrating important functions across numerous carcinomas. Unfortunately, it is still elusive towards TRIM47 expression, characteristic, and biological function in brain gliomas.

Methods

Public database analysis was applied to analyze TRIM47 expression, and quantitative real-time PCR (qRT-PCR) was applied to detect the expression of TRIM47 in 9 paired tissues of glioma. The Cancer Genome Atlas (TCGA) and the Chinese Glioma Genome Atlas (CGGA) databases were applied to evaluate the overall survival (OS). Gene Ontology (GO) term and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were applied to analyze differentially expressed gene (DEG) functions. In vitro experiments were performed to validate TRIM47-mediated effects on glioma cell proliferation, migration, and invasion.

Results

Compared to that in normal tissues, TRIM47 expression was greatly higher in glioma tissues, and its expression level was associated with different grades of glioma. Our data indicated that highly expressed TRIM47 displayed an association with the poor prognosis of glioma patients. Ablating TRIM47 obviously impeded glioma cell invasion and migration.

Conclusion

TRIM47 could modulate glioma cell proliferation, invasion, and migration. Highly expressed TRIM47 exhibited a correlation with poor prognosis. All data imply that TRIM47 is a probable biomarker for glioma and has the potentiality to become a newly generated target for glioma treatment.

Inhibition of TRIM14 protects cerebral ischemia/reperfusion injury through regulating NF-κB/NLRP3 pathway-mediated inflammation and apoptosis

PURPOSE

Many proteins in tripartite motif (TRIM) family have been reported to play an important role in cerebral ischemia/reperfusion (I/R) injury. This study was designed to investigate the effect of TRIM14 on the cerebral I/R injury in rats.

METHODS

The rat model was constructed through inserting thread into the middle cerebral artery. The expression of TRIM14 was measured by qRT-PCR, immunoblotting, and immunofluorescence. The hippocampal sections were stained with 2,3,5-triphenyltetrazolium chloride (TTC) to determine infarct volume and used for measuring the neurologic deficit score and brain water content. The H&E staining was used for immunohistochemical (IHC) staining. The number of apoptotic cells was measured by fluorescence microscopy. The levels of IL-6, IL-1β, and TNFα were detected by qRT-PCR and ELISA. The swimming speed, latency time, and number of platform crossings were measured by the water maze test.

RESULTS

TRIM14 was significantly enhanced in rats with cerebral I/R injury compared to Sham rats, showing its highest level at 24 h after I/R. TRIM14 inhibition reduced ischemic brain injury, suppressed neuron apoptosis, suppressed inflammation, and improved cognitive dysfunction in rats with cerebral I/R injury. TRIM14 inhibition also suppressed the activation of NF-κB/NLRP3 pathway in rats with cerebral I/R injury.

CONCLUSION

In conclusion, the expression of TRIM14 was increased in rats with cerebral I/R injury, the protective effect of TRIM14 inhibitor on cerebral I/R injury in rats depends on its anti-apoptotic and anti-inflammatory effect. The underlying mechanism was, at least partially, through regulating NF-κB/NLRP3 pathway.

Tripartite Motif-Containing 27 Attenuates Liver Ischemia/Reperfusion Injury by Suppressing Transforming Growth Factor β-Activated Kinase 1 (TAK1) by TAK1 Binding Protein 2/3 Degradation

BACKGROUND AND AIMS

Hepatic ischemia-reperfusion (I/R) injury, which mainly involves inflammatory responses and apoptosis, is a common cause of organ dysfunction in liver transplantation (LT). As a critical mediator of inflammation and apoptosis in various cell types, the role of tripartite motif-containing (TRIM) 27 in hepatic I/R injury remains worthy of study.

APPROACH AND RESULTS

This study systemically evaluated the putative role of TRIM27/transforming growth factor β-activated kinase 1 (TAK1)/JNK (c-Jun N-terminal kinase)/p38 signaling in hepatic I/R injury. TRIM27 expression was significantly down-regulated in liver tissue from LT patients, mice subjected to hepatic I/R surgery, and hepatocytes challenged by hypoxia/reoxygenation (H/R) treatment. Subsequently, using global Trim27 knockout mice (Trim27-KO mice) and hepatocyte-specific Trim27 transgenic mice (Trim27-HTG mice), TRIM27 functions to ameliorate liver damage, reduce the inflammatory response, and prevent cell apoptosis. In parallel in vitro studies, activating TRIM27 also prevented H/R-induced hepatocyte inflammation and apoptosis. Mechanistically, TRIM27 constitutively interacted with the critical components, TAK1 and TAK1 binding protein 2/3 (TAB2/3), and promoted the degradation of TAB2/3, leading to inactivation of TAK1 and the subsequent suppression of downstream JNK/p38 signaling.

CONCLUSIONS

TRIM27 is a key regulator of hepatic I/R injury by mediating the degradation of TAB2/3 and suppression of downstream TAK1-JNK/p38 signaling. TRIM27 may be a promising approach to protect the liver against I/R-mediated hepatocellular damage in transplant recipients.

TRIM Proteins in Inflammation: from Expression to Emerging Regulatory Mechanisms

Inflammation is an immune response to exogenous or endogenous insults that helps to maintain the tissue homeostasis under stressful conditions. Depending on the differential types of insults, inflammation is classified into microbial, autoimmune, metabolic, allergic, and physical inflammation. With regard to its involvement in the pathogenesis of most of human diseases, dissecting the key molecules in the regulation of inflammatory process is vital for the prevention and therapeutics of human diseases. Tripartite motif (TRIM) proteins are a versatile family of E3 ligases, which are composed of > 80 distinct members in humans recognized for their roles in antiviral responses. Recently, a large number of studies have shown the regulatory roles of TRIM proteins in mediating the inflammation. Herein in this review, we discuss the aberrations of TRIM proteins in autoimmune and autoinflammatory diseases, with a focus on the regulation of different components of inflammatory process, including inflammasome, NF-κB signaling, type I IFN (interferon) production, and Th1/Th17 cell differentiation. Importantly, elucidation of the mechanism underlying the regulation of inflammation by TRIMs provides insights into the use of TRIMs as therapeutic targets for disease treatment.

S100a8 silencing attenuates inflammation, oxidative stress and apoptosis in BV2 cells induced by oxygen‑glucose deprivation and reoxygenation by upregulating GAB1 expression

S100a8 serves an important role in cell differentiation and is abnormally expressed in common tumors, but there are few studies on the association between S100a8 and brain I/R injury. The present study aimed to investigate the role of S100a8 in oxygen-glucose deprivation and reoxygenation (OGD/R)-induced BV2 microglia cell injury, and to elucidate the potential underlying molecular mechanisms. BV2 cells were exposed to OGD/R to mimic ischemia/reperfusion (I/R) injury in vitro. S100a8 expression was detected via reverse transcription-quantitative PCR and western blot analyses. Following transfection with short hairpin RNAs targeting S100a8, the levels of inflammatory cytokines and oxidative stress-related factors were determined using commercial kits. Apoptosis was assessed using flow cytometric analysis and the expression levels of apoptosis-related proteins were determined using western blot analysis. Subsequently, the mRNA and protein levels of Grb2-associated binder 1 (GAB1) were assessed following S100a8 silencing. Immunoprecipitation (IP) was performed to verify the association between S100a8 and GAB1. The levels of inflammation, oxidative stress and apoptosis were assessed following GAB1 silencing, along with S100a8 silencing in BV2 cells subjected to OGD/R. The results indicated that exposure to OGD/R markedly upregulated S100a8 expression in BV2 cells. S100a8 silencing inhibited inflammation, oxidative stress and apoptosis, accompanied by changes in the expression of related proteins. The IP assay revealed a strong interaction between GAB1 and S100a8. In addition, GAB1 silencing reversed the inhibitory effects of S100a8 silencing on inflammation, oxidative stress and apoptosis in OGD/R-stimulated BV2 cells. Taken together, the results of the present study demonstrated that S100a8 silencing alleviated inflammation, oxidative stress and the apoptosis of BV2 cells induced by OGD/R, partly by upregulating the expression of GAB1. Thus, these findings may potentially provide a novel direction to develop therapeutic strategies for cerebral I/R injury.