TRIM32 Deficiency Impairs Synaptic Plasticity by Excitatory-Inhibitory Imbalance via Notch Pathway

The Notch Signaling Pathway: A Potential Target for Mental Disorders

The highly conserved Notch signaling pathway plays a critical role in cell fate determination during metazoan development through cell-to-cell communication. The classical pathway consists of Notch receptors, ligands, intracellular effectors, DNA-binding proteins, and other regulatory molecules. Recent research has highlighted its involvement in the pathogenesis of several diseases. In autism, bipolar disorder, and schizophrenia, the Notch signaling pathway is implicated in key processes such as neuronal development and synaptic plasticity. Furthermore, it has been shown to play significant roles in other mental health conditions, including anxiety, depression, post-traumatic stress disorder, and neurocognitive disorders. However, the precise mechanisms underlying the contribution of Notch to these conditions remain poorly understood. This review examines the current understanding of the Notch signaling pathway in mental disorders, highlighting its role in their pathophysiology and summarizing therapeutic strategies aimed at modulating this pathway to improve mental health outcomes.

A Homozygous ATP2A2 Variant Alters Sarcoendoplasmic Reticulum Ca2+-ATPase 2 Function in Skeletal Muscle and Causes a Novel Vacuolar Myopathy

AIMS

Sarcoendoplasmic reticulum Ca2+-ATPase 2 (SERCA2), encoded by ATP2A2, is a key protein involved in intracellular Ca2+ homeostasis. The SERCA2a isoform is predominantly expressed in cardiomyocytes and type I myofibres. Variants in this gene are related to Darier disease, an autosomal dominant dermatologic disorder, but have never been linked to myopathy. We describe four patients suffering from a novel myopathy caused by a homozygous missense variant in ATP2A2.

METHODS

We studied a family with four individuals suffering from an adult-onset skeletal myopathy. We evaluated the clinicopathological phenotype, muscle imaging, and genetic workup including whole genome sequencing and segregation analysis. SERCA2 expression in skeletal muscle was assessed. Functional studies to evaluate Ca2+ handling in patient myotubes in response to electrical stimulation or caffeine exposure were performed.

RESULTS

Four sisters developed slowly progressive proximal weakness in adulthood. Biopsy findings showed small vacuoles restricted to type I myofibres. Ultrastructural analysis showed sarcotubular dilation and autophagic vacuoles. Genome sequencing revealed a homozygous variant in ATP2A2 (c.1117G > A, p.(Glu373Lys)) which segregated with the disease. Immunohistochemistry suggested that there was SERCA2 mislocalisation in patient myofibres. Western blotting did not show changes in the amount of protein. In vitro functional studies revealed delayed sarcoendoplasmic reticulum Ca2+ reuptake in patient myotubes, consistent with an altered pumping capacity of SERCA2 after cell stimulation.

CONCLUSIONS

We report a novel adult-onset vacuolar myopathy caused by a homozygous variant in ATP2A2. Biopsy findings and functional studies demonstrating an impaired function of SERCA2 and consequent Ca2+ dysregulation in slow-twitch skeletal myofibres highly support the pathogenicity of the variant.

TRIM32 Inhibits NEK7 Ubiquitylation-Dependent Microglia Pyroptosis After Spinal Cord Injury

Spinal cord injury (SCI) is a disabling disease associated with microglial activation. Tripartite motif containing 32 (TRIM32) is an E3 ubiquitin ligase that plays a role in SCI. This study aimed to explore the role of TRIM32 in SCI and its potential mechanisms. We established an SCI mouse model to assess the function of TRIM32 using quantitative real-time polymerase chain reaction (qPCR), and hematoxylin and eosin staining. Additionally, a lipopolysaccharides (LPS)-induced cell injury model was generated to explore the impact of TRIM32 on pyroptosis using qPCR, propidium iodide staining, and western blotting. The ubiquitylation of NEK7 was analyzed using western blotting, co-immunoprecipitation, and immunofluorescence staining. The results showed that TRIM32 expression was increased in SCI mice and LPS-induced BV-2 cells. Overexpression of TRIM32 ameliorated SCI in mice and suppressed pyroptosis in LPS-treated BV-2 cells. Additionally, the E3 ligase TRIM32 promoted the ubiquitylation of NEK7 at the K64 site, leading to the downregulation of NEK7 levels. Inhibiting NEK7 ubiquitylation reversed the suppression of pyroptosis by TRIM32. In conclusion, TRIM32 inhibits microglia pyroptosis by facilitating the ubiquitylation of NEK7 at the K64 site, thereby alleviating the progression of SCI. The findings suggest that TRIM32 has the potential to be a therapeutic target of SCI.

Congenital myopathies: pathophysiological mechanisms and promising therapies

Congenital myopathies (CMs) are a kind of non-progressive or slow-progressive muscle diseases caused by genetic mutations, which are currently defined and categorized mainly according to their clinicopathological features. CMs exhibit pleiotropy and genetic heterogeneity. Currently, supportive treatment and pharmacological remission are the mainstay of treatment, with no cure available. Some adeno-associated viruses show promising prospects in the treatment of MTM1 and BIN1-associated myopathies; however, such gene-level therapeutic interventions target only specific mutation types and are not generalizable. Thus, it is particularly crucial to identify the specific causative genes. Here, we outline the pathogenic mechanisms based on the classification of causative genes: excitation-contraction coupling and triadic assembly (RYR1, MTM1, DNM2, BIN1), actin-myosin interaction and production of myofibril forces (NEB, ACTA1, TNNT1, TPM2, TPM3), as well as other biological processes. Furthermore, we provide a comprehensive overview of recent therapeutic advancements and potential treatment modalities of CMs. Despite ongoing research endeavors, targeted strategies and collaboration are imperative to address diagnostic uncertainties and explore potential treatments.

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.

Tripartite Motif-Containing Protein 32 (TRIM32): What Does It Do for Skeletal Muscle?

Tripartite motif-containing protein 32 (TRIM32) is a member of the tripartite motif family and is highly conserved from flies to humans. Via its E3 ubiquitin ligase activity, TRIM32 mediates and regulates many physiological and pathophysiological processes, such as growth, differentiation, muscle regeneration, immunity, and carcinogenesis. TRIM32 plays multifunctional roles in the maintenance of skeletal muscle. Genetic variations in the TRIM32 gene are associated with skeletal muscular dystrophies in humans, including limb-girdle muscular dystrophy type 2H (LGMD2H). LGMD2H-causing genetic variations of TRIM32 occur most frequently in the C-terminal NHL (ncl-1, HT2A, and lin-41) repeats of TRIM32. LGMD2H is characterized by skeletal muscle dystrophy, myopathy, and atrophy. Surprisingly, most patients with LGMD2H show minimal or no dysfunction in other tissues or organs, despite the broad expression of TRIM32 in various tissues. This suggests more prominent roles for TRIM32 in skeletal muscle than in other tissues or organs. This review is focused on understanding the physiological roles of TRIM32 in skeletal muscle, the pathophysiological mechanisms mediated by TRIM32 genetic variants in LGMD2H patients, and the correlations between TRIM32 and Duchenne muscular dystrophy (DMD).

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.

AQP4 Aggravates Cognitive Impairment in Sepsis-Associated Encephalopathy through Inhibiting Nav 1.6-Mediated Astrocyte Autophagy

The pathology of sepsis-associated encephalopathy (SAE) is related to astrocyte-inflammation associated with aquaporin-4 (AQP4). The aim here is to investigate the effects of AQP4 associated with SAE and reveal its underlying mechanism causing cognitive impairment. The in vivo experimental results reveal that AQP4 in peripheral blood of patients with SAE is up-regulated, also the cortical and hippocampal tissue of cecal ligation and perforation (CLP) mouse brain has significant rise in AQP4. Furthermore, the data suggest that AQP4 deletion could attenuate learning and memory impairment, attributing to activation of astrocytic autophagy, inactivation of astrocyte and downregulate the expression of proinflammatory cytokines induced by CLP or lipopolysaccharide (LPS). Furthermore, the activation effect of AQP4 knockout on CLP or LPS-induced PPAR-γ inhibiting in astrocyte is related to intracellular Ca2+ level and sodium channel activity. Learning and memory impairment in SAE mouse model are attenuated by AQP4 knockout through activating autophagy, inhibiting neuroinflammation leading to neuroprotection via down-regulation of Nav 1.6 channels in the astrocytes. This results in the reduction of Ca2+ accumulation in the cell cytosol furthermore activating the inhibition of PPAR-γ signal transduction pathway in astrocytes.

Roles of the Notch signaling pathway and microglia in autism

The Notch signaling pathway is mainly involved in the regulation of neural stem cell proliferation, survival and differentiation during the development of the central nervous system. As a neurodevelopmental disorder, autism is associated with an abnormal increase in the number of microglia in several brain regions. These findings suggest that the pathogenesis of autism may be related to the Notch signaling pathway and microglia. In this review, we discuss how Notch pathway activity leads to behavioral abnormalities such as learning and memory impairment by influencing neuronal biological activities. An increase in microglial protein synthesis and abnormal autophagy can affect synaptic development and lead to behavioral abnormalities, and all of these changes can lead to autism. Furthermore, the Notch signaling pathway regulates the activation and differentiation of microglia and promotes inflammatory responses, leading to the occurrence of autism. When excessive reactive oxygen species (ROS) secreted by microglia cannot be cleared by autophagy in a timely manner, Notch signaling pathway activity is affected, possibly further increasing susceptibility to autism. This review reveals the mechanism underlying the role of the Notch signaling pathway, microglia and their interaction in the pathogenesis of autism and provides a theoretical reference for targeted clinical therapies for autism.

The Notch signaling pathway in skeletal muscle health and disease

The Notch signaling pathway is a key regulator of skeletal muscle development and regeneration. Over the past decade, the discoveries of three new muscle disease genes have added a new dimension to the relationship between the Notch signaling pathway and skeletal muscle: MEGF10, POGLUT1, and JAG2. We review the clinical syndromes associated with pathogenic variants in each of these genes, known molecular and cellular functions of their protein products with a particular focus on the Notch signaling pathway, and potential novel therapeutic targets that may emerge from further investigations of these diseases. The phenotypes associated with two of these genes, POGLUT1 and JAG2, clearly fall within the realm of muscular dystrophy, whereas the third, MEGF10, is associated with a congenital myopathy/muscular dystrophy overlap syndrome classically known as early-onset myopathy, areflexia, respiratory distress, and dysphagia. JAG2 is a canonical Notch ligand, POGLUT1 glycosylates the extracellular domain of Notch receptors, and MEGF10 interacts with the intracellular domain of NOTCH1. Additional genes and their encoded proteins relevant to muscle function and disease with links to the Notch signaling pathway include TRIM32, ATP2A1 (SERCA1), JAG1, PAX7, and NOTCH2NLC. There is enormous potential to identify convergent mechanisms of skeletal muscle disease and new therapeutic targets through further investigations of the Notch signaling pathway in the context of skeletal muscle development, maintenance, and disease.

The roles and targeting options of TRIM family proteins in tumor

Tripartite motif (TRIM) containing proteins are a class of E3 ubiquitin ligases, which are critically implicated in the occurrence and development of tumors. They can function through regulating various aspects of tumors, such as tumor proliferation, metastasis, apoptosis and the development of drug resistance during tumor therapy. Some members of TRIM family proteins can mediate protein ubiquitination and chromosome translocation via modulating several signaling pathways, like p53, NF-κB, AKT, MAPK, Wnt/β-catenin and other molecular regulatory mechanisms. The multi-domain nature/multi-functional biological role of TRIMs implies that blocking just one function or one domain might not be sufficient to obtain the desired therapeutic outcome, therefore, a detailed and systematic understanding of the biological functions of the individual domains of TRIMs is required. This review mainly described their roles and underlying mechanisms in tumorigenesis and progression, and it might shade light on a potential targeting strategy for TRIMs in tumor treatment, especially using PROTACs.

Two-hour acute restraint stress facilitates escape behavior and learning outcomes through the activation of the Cdk5/GR P S211 pathway in male mice

Acute stress exerts pleiotropic actions on learning behaviors. The induced negative effects are sometimes adopted to measure the efficacy of particular drugs. Until now, there are no detailed experimental data on the time-gradient effects of acute stress. Here, we developed the time gradient acute restraint stress (ARS) model to precisely assess the roles of different restrain times on inducing acute stress. Time gradient ARS facilitates escape behaviors and learning outcomes, peaking at 2 h-ARS and then declining to baseline at 3.5 h-ARS as confirmed by time gradient post-stress data. Furthermore, time gradient ARS activates glucocorticoid receptor (GR) phosphorylation site at Serine211 (P S221) as an inverted V-shaped pattern peaking at 2 h-ARS, whereas that of the GR phosphorylation site at Serine226 (P S226) from 2 h-ARS to 3.5 h-ARS. The 2 h-ARS but not 3.5 h-ARS enhances synaptic plasticity and genes transcription associated with learning and memory in the hippocampus of male mice. The Cdk5 inhibitor, roscovitine, blocks this facilitation effect by intervening in GR phosphorylation at Serine211 in the 2 h-ARS mice. Altogether, these findings show that the time gradient ARS selectively activates GR phospho-isoforms and differentially influences the behaviors along with maintaining a relationship between 2 h-ARS and Cdk5/GR P S211-mediated transcriptional activity.

The E3 ligase Thin controls homeostatic plasticity through neurotransmitter release repression

Synaptic proteins and synaptic transmission are under homeostatic control, but the relationship between these two processes remains enigmatic. Here, we systematically investigated the role of E3 ubiquitin ligases, key regulators of protein degradation-mediated proteostasis, in presynaptic homeostatic plasticity (PHP). An electrophysiology-based genetic screen of 157 E3 ligase-encoding genes at the Drosophila neuromuscular junction identified thin, an ortholog of human tripartite motif-containing 32 (TRIM32), a gene implicated in several neurological disorders, including autism spectrum disorder and schizophrenia. We demonstrate that thin functions presynaptically during rapid and sustained PHP. Presynaptic thin negatively regulates neurotransmitter release under baseline conditions by limiting the number of release-ready vesicles, largely independent of gross morphological defects. We provide genetic evidence that thin controls release through dysbindin, a schizophrenia-susceptibility gene required for PHP. Thin and Dysbindin localize in proximity within presynaptic boutons, and Thin degrades Dysbindin in vitro. Thus, the E3 ligase Thin links protein degradation-dependent proteostasis of Dysbindin to homeostatic regulation of neurotransmitter release.

Integrative analysis of expression profile indicates the ECM receptor and LTP dysfunction in the glioma-related epilepsy

Background

Seizures are a common symptom in glioma patients, and they can cause brain dysfunction. However, the mechanism by which glioma-related epilepsy (GRE) causes alterations in brain networks remains elusive.

Objective

To investigate the potential pathogenic mechanism of GRE by analyzing the dynamic expression profiles of microRNA/ mRNA/ lncRNA in brain tissues of glioma patients.

Methods

Brain tissues of 16 patients with GRE and 9 patients with glioma without epilepsy (GNE) were collected. The total RNA was dephosphorylated, labeled, and hybridized to the Agilent Human miRNA Microarray, Release 19.0, 8 × 60 K. The cDNA was labeled and hybridized to the Agilent LncRNA + mRNA Human Gene Expression Microarray V3.0, 4 × 180 K. The raw data was extracted from hybridized images using Agilent Feature Extraction, and quantile normalization was performed using the Agilent GeneSpring. P-value < 0.05 and absolute fold change > 2 were considered the threshold of differential expression data. Data analyses were performed using R and Bioconductor.

Results

We found that 3 differentially expressed miRNAs (miR-10a-5p, miR-10b-5p, miR-629-3p), 6 differentially expressed lncRNAs (TTN-AS1, LINC00641, SNHG14, LINC00894, SNHG1, OIP5-AS1), and 49 differentially expressed mRNAs play a vitally critical role in developing GRE. The expression of GABARAPL1, GRAMD1B, and IQSEC3 were validated more than twofold higher in the GRE group than in the GNE group in the validation cohort. Pathways including ECM receptor interaction and long-term potentiation (LTP) may contribute to the disease’s progression. Meanwhile, We built a lncRNA-microRNA-Gene regulatory network with structural and functional significance.

Conclusion

These findings can offer a fresh perspective on GRE-induced brain network changes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-022-08665-8.

Ppp4r3a deficiency leads to depression-like behaviors in mice by modulating the synthesis of synaptic proteins

Chronic stress is one of the main risk factors for the onset of major depressive disorder. Chronic unpredictable mild stress results in reduced expression of synaptic proteins and depression-like behaviors in rodent models. However, the upstream molecule that senses the demand for synaptic proteins and initiates their synthesis under chronic stress remains unknown. In this study, chronic unpredictable mild stress reduced the expression of PPP4R3A in the prefrontal cortex and hippocampus in mice. Selective knockout of Ppp4r3a in the cortex and hippocampus mimicked the depression- and anxiety-like behavioral effects of chronic stress in mice. Notably, Ppp4r3a deficiency led to downregulated mTORC1 signaling, which resulted in reduced synthesis of synaptic proteins and impaired synaptic functions. By contrast, overexpression of Ppp4r3a in the cortex and hippocampus protected against behavioral and synaptic deficits induced by chronic stress in a PPP4R3A-mTORC1-dependent manner. Rapamycin treatment of Ppp4r3a-overexpressing neurons blocked the regulatory effect of Ppp4r3a on the synthesis of synaptic proteins by directly inhibiting mTORC1. Overall, our results reveal a regulatory role of Ppp4r3a in driving synaptic protein synthesis in chronic stress.

Reducing Nav1.6 expression attenuates the pathogenesis of Alzheimer's disease by suppressing BACE1 transcription

Aberrant increases in neuronal network excitability may contribute to cognitive deficits in Alzheimer's disease (AD). However, the mechanisms underlying hyperexcitability of neurons are not fully understood. Voltage‐gated sodium channels (VGSC or Nav), which are involved in the formation of excitable cell's action potential and can directly influence the excitability of neural networks, have been implicated in AD‐related abnormal neuronal hyperactivity and higher incidence of spontaneous non‐convulsive seizures. Here, we have shown that the reduction of VGSC α‐subunit Nav1.6 (by injecting adeno‐associated virus (AAV) with short hairpin RNA (shRNA) into the hippocampus) rescues cognitive impairments and attenuates synaptic deficits in APP/PS1 transgenic mice. Concurrently, amyloid plaques in the hippocampus and levels of soluble Aβ are significantly reduced. Interfering with Nav1.6 reduces the transcription level of β‐site APP‐cleaving enzyme 1 (BACE1), which is Aβ‐dependent. In the presence of Aβ oligomers, knockdown of Nav1.6 reduces intracellular calcium overload by suppressing reverse sodium–calcium exchange channel, consequently increasing inactive NFAT1 (the nuclear factor of activated T cells) levels and thus reducing BACE1 transcription. This mechanism leads to a reduction in the levels of Aβ in APP/PS1 transgenic mice, alleviates synaptic loss, improves learning and memory disorders in APP/PS1 mice after downregulating Nav1.6 in the hippocampus. Our study offers a new potential therapeutic strategy to counteract hippocampal hyperexcitability and subsequently rescue cognitive deficits in AD by selective blockade of Nav1.6 overexpression and/or hyperactivity.

Fluoxetine attenuates apoptosis in early brain injury after subarachnoid hemorrhage through Notch1/ASK1/p38 MAPK signaling pathway

Subarachnoid hemorrhage (SAH) is a severe brain condition associated with a significantly high incidence and mortality. As a consequence of SAH, early brain injury (EBI) may contribute to poor SAH patient outcomes. Apoptosis is a signaling pathway contributing to post-SAH early brain injury and the diagnosis of the disease. Fluoxetine is a well-studied serotonin selective reuptake inhibitor (SSRI). However, its role in apoptosis has not been clearly understood. The present investigation assessed the effects of Fluoxetine in apoptosis and the potential Notch1/ASK1/p38 MAPK signaling pathway in EBI after SAH. Adult C57BL/6 J mice were subjected to SAH. Study mice (56) were randomly divided into 4 groups: the surgery without SAH (sham (n = 8), SAH+ vehicle; (SAH+V) (n = 16), surgery+ Fluoxetine (Fluox), (n = 16) and SAH+ Fluoxetine (n = 16). Various parameters were investigated 12, 24, 48, and 72 h after induction of SAH. Western blot analysis, terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL) staining, Immunohistochemistry (IHC), and flow cytometry were carried out in every experimental group. According to the findings, the SAH downregulated NOTCH1 signaling pathway, Jlk6 inhibited Notch1, Notch1 inactivation increased apoptotic protein expression and suppressed Bax, and cytochrome C. Fluoxetine reversed the effects of notch1 inhibition in SAH. The Neuroprotective Fluoxetine effects involved suppression of apoptosis post-SAH. In summary, early Fluoxetine treatment significantly attenuates apoptosis and the expression of apoptosis-related proteins after 72 h post-SAH. Fluoxetine may ameliorate early brain injury after subarachnoid hemorrhage through anti-apoptotic effects and Notch1/ASK1/p38 MAPK signaling pathway.

TRIM32 Deficiency Impairs the Generation of Pyramidal Neurons in Developing Cerebral Cortex

Excitatory-inhibitory imbalance (E/I) is a fundamental mechanism underlying autism spectrum disorders (ASD). TRIM32 is a risk gene genetically associated with ASD. The absence of TRIM32 causes impaired generation of inhibitory GABAergic interneurons, neural network hyperexcitability, and autism-like behavior in mice, emphasizing the role of TRIM32 in maintaining E/I balance, but despite the description of TRIM32 in regulating proliferation and differentiation of cultured mouse neural progenitor cells (NPCs), the role of TRIM32 in cerebral cortical development, particularly in the production of excitatory pyramidal neurons, remains unknown. The present study observed that TRIM32 deficiency resulted in decreased numbers of distinct layer-specific cortical neurons and decreased radial glial cell (RGC) and intermediate progenitor cell (IPC) pool size. We further demonstrated that TRIM32 deficiency impairs self-renewal of RGCs and IPCs as indicated by decreased proliferation and mitosis. A TRIM32 deficiency also affects or influences the formation of cortical neurons. As a result, TRIM32-deficient mice showed smaller brain size. At the molecular level, RNAseq analysis indicated reduced Notch signalling in TRIM32-deficient mice. Therefore, the present study indicates a role for TRIM32 in pyramidal neuron generation. Impaired generation of excitatory pyramidal neurons may explain the hyperexcitability observed in TRIM32-deficient mice.

TRIM32 Inhibition Attenuates Apoptosis, Oxidative Stress, and Inflammatory Injury in Podocytes Induced by High Glucose by Modulating the Akt/GSK-3β/Nrf2 Pathway

Hyperglycemia-induced oxidative stress in podocytes exerts a major role in the pathological process of diabetic nephropathy. Tripartite motif-containing protein 32 (TRIM32) has been reported to be a key protein in the modulation of cellular apoptosis and oxidative stress under various pathological processes. However, whether TRIM32 participates in the regulation of high glucose (HG)-induced injury in podocytes has not been investigated. This work aimed to assess the possible role of TRIM32 in mediating HG-induced apoptosis, oxidative stress, and inflammatory response in podocytes in vitro. Our results showed a marked increase in TRIM32 expression in HG-exposed podocytes and the glomeruli of diabetic mice. Loss-of-function experiments showed that TRIM32 knockdown improves the viability of HG-stimulated podocytes and suppresses HG-induced apoptosis, oxidative stress, and inflammatory responses in podocytes. Further investigation revealed that TRIM32 inhibition enhances the activation of nuclear factor erythroid 2-related factor 2 (Nrf2) signaling, which is associated with the modulation of the Akt/glycogen synthase kinase-3β (GSK-3β) axis in podocytes following HG exposure. However, Akt suppression abrogated the TRIM32 knockdown-mediated activation of Nrf2 in HG-exposed podocytes. Nrf2 knockdown also markedly abolished the protective effects induced by TRIM32 inhibition o in HG-exposed podocytes. In summary, this work demonstrated that TRIM32 inhibition protects podocytes from HG-induced injury by potentiating Nrf2 signaling through modulation of Akt/GSK-3β signaling. The findings reveal the potential role of TRIM32 in mediating podocyte injury during the progression of diabetic nephropathy.