Protein Arginine Methyltransferase Research Articles

Mechanistic safety assessment via multi-omic characterisation of systemic pathway perturbations following in vivo MAT2A inhibition

The tumour suppressor p16/CDKN2A and the metabolic gene, methyl-thio-adenosine phosphorylase (MTAP), are frequently co-deleted in some of the most aggressive and currently untreatable cancers. Cells with MTAP deletion are vulnerable to inhibition of the metabolic enzyme, methionine-adenosyl transferase 2A (MAT2A), and the protein arginine methyl transferase (PRMT5). This synthetic lethality has paved the way for the rapid development of drugs targeting the MAT2A/PRMT5 axis. MAT2A and its liver- and pancreas-specific isoform, MAT1A, generate the universal methyl donor S-adenosylmethionine (SAM) from ATP and methionine. Given the pleiotropic role SAM plays in methylation of diverse substrates, characterising the extent of SAM depletion and downstream perturbations following MAT2A/MAT1A inhibition (MATi) is critical for safety assessment. We have assessed in vivo target engagement and the resultant systemic phenotype using multi-omic tools to characterise response to a MAT2A inhibitor (AZ’9567). We observed significant SAM depletion and extensive methionine accumulation in the plasma, liver, brain and heart of treated rats, providing the first assessment of both global SAM depletion and evidence of hepatic MAT1A target engagement. An integrative analysis of multi-omic data from liver tissue identified broad perturbations in pathways covering one-carbon metabolism, trans-sulfuration and lipid metabolism. We infer that these pathway-wide perturbations represent adaptive responses to SAM depletion and confer a risk of oxidative stress, hepatic steatosis and an associated disturbance in plasma and cellular lipid homeostasis. The alterations also explain the dramatic increase in plasma and tissue methionine, which could be used as a safety and PD biomarker going forward to the clinic.

Regulation of RORα Stability through PRMT5-Dependent Symmetric Dimethylation.

Retinoic acid receptor-related orphan receptor alpha (RORα), a candidate tumor suppressor, is prevalently downregulated or lost in malignant breast cancer cells. However, the mechanisms of how RORα expression is regulated in breast epithelial cells remain incompletely understood. Protein arginine N-methyltransferase 5 (PRMT5), a type II methyltransferase catalyzing the symmetric methylation of the amino acid arginine in target proteins, was reported to regulate protein stability. To study whether and how PRMT5 regulates RORα, we examined the direct interaction between RORα and PRMT5 by immunoprecipitation and GST pull-down assays. The results showed that PRMT5 directly bound to RORα, and PRMT5 mainly symmetrically dimethylated the DNA-binding domain (DBD) but not the ligand-binding domain (LBD) of RORα. To investigate whether RORα protein stability is regulated by PRMT5, we transfected HEK293FT cells with RORα and PRMT5-expressing or PRMT5-silencing (shPRMT5) vectors and then examined RORα protein stability by a cycloheximide chase assay. The results showed that PRMT5 increased RORα protein stability, while silencing PRMT5 accelerated RORα protein degradation. In PRMT5-silenced mammary epithelial cells, RORα protein expression was decreased, accompanied by an enhanced epithelial-mesenchymal transition morphology and cell invasion and migration abilities. In PRMT5-overexpressed mammary epithelial cells, RORα protein was accumulated, and cell invasion was suppressed. These findings revealed a novel mechanism by which PRMT5 regulates RORα protein stability.

Role of protein arginine methyltransferase 1 in obesity-related metabolic disorders: Research progress and implications.

Obesity has become a major global problem that significantly confers an increased risk of developing life-threatening complications, including type 2 diabetes mellitus, fatty liver disease and cardiovascular diseases. Protein arginine methyltransferases (PRMTs) are enzymes that catalyse the methylation of target proteins. They are ubiquitous in eukaryotes and regulate transcription, splicing, cell metabolism and RNA biology. As a key, epigenetically modified enzyme, protein arginine methyltransferase 1 (PRMT1) is involved in obesity-related metabolic processes, such as lipid metabolism, the insulin signalling pathway, energy balance and inflammation, and plays an important role in the pathology of obesity-related metabolic disorders. This review summarizes recent research on the role of PRMT1 in obesity-related metabolic disorders. The primary objective was to comprehensively elucidate the functional role and regulatory mechanisms of PRMT1. Moreover, this study attempts to review the pathogenesis of PRMT1-mediated obesity-related metabolic disorders, thereby offering pivotal information for further studies and clinical treatment.

Association between protein arginine N-methyltransferase 1 polymorphism and overt diabetic nephropathy: Role of asymmetric dimethylarginine in vascular tone

Backgroundω-NG,NG-asymmetric dimethylarginine (ADMA) regulates vascular tone and may participate in the pathogenesis of diabetic nephropathy (DN). ObjectiveTo investigate whether single-nucleotide polymorphisms (SNPs) around the protein arginine N-methyltransferase 1 gene (PRMT1) influence ADMA dynamics and DN incidence and severity. MethodsThis study utilized a hospital-based database containing 310 Japanese patients with type 2 diabetes mellitus (T2DM). The association of PRMT1-related tagged SNPs with DN stage distribution was examined using a dominant model of minor alleles. PRMT1 mRNA, serum ADMA, reactive hyperemia-peripheral arterial tonometry index (RHI), and brachial-ankle pulse wave velocity (baPWV) were compared between the genotype-based subgroups of causal SNP, and correlations between these variables were evaluated. ResultsThe composition of DN stages significantly differed between the GG and GA + AA subgroups of rs892151 (p = 0.026). In a propensity-matching cohort of rs892151, the GA + AA subgroup had an increased incidence of overt DN (odds ratio 2.92, 95 % confidence interval 1.12–7.62, p = 0.028), along with higher PRMT1 mRNA, serum ADMA levels, and baPWV than the GG subgroup (p < 0.001, p = 0.023 and 0.047, respectively). There were correlations between PRMT1 mRNA and serum ADMA levels, between serum ADMA levels and RHI, and between baPWV and urinary albumin excretion (r = 0.335, p < 0.001, r = -0.221, p = 0.029, and r = 0.254, p = 0.004, respectively). ConclusionsT2DM patients carrying the PRMT1-related variant rs892151 were susceptible to overt DN. ADMA-mediated endothelial dysfunction and arterial stiffness may be involved in the variant-related pathogenesis of overt DN.

Discovery of a first-in-class degrader for the protein arginine methyltransferase 6 (PRMT6)

PRMT6 is a member of the protein arginine methyltransferase family, which participates in a variety of physical processes and plays an important role in the occurrence and development of tumors. Using small molecules to design and synthesize targeted protein degraders is a new strategy for drug development. Here, we report the first-in-class degrader SKLB-0124 for PRMT6 based on the hydrophobic tagging (HyT) method.Importantly, SKLB-0124 induced proteasome dependent degradation of PRMT6 and significantly inhibited the proliferation of HCC827 and MDA-MB-435 cells. Moreover, SKLB-0124 effectively induced apoptosis and cell cycle arrest in these two cell lines. Our data clarified that SKLB-0124 is a promising selective PRMT6 degrader for cancer therapy which is worthy of further evaluation.

A CARM1 Inhibitor Potently Suppresses Breast Cancer Both In Vitro and In Vivo.

CARM1, belonging to the protein arginine methyltransferase (PRMT) family, is intricately associated with the progression of cancer and is viewed as a promising target for both cancer diagnosis and therapy. However, the number of specific and potent CARM1 inhibitors is limited. We herein discovered a CARM1 inhibitor, iCARM1, that showed better specificity and activity toward CARM1 compared to the known CARM1 inhibitors, EZM2302 and TP-064. Similar to CARM1 knockdown, iCARM1 suppressed the expression of oncogenic estrogen/ERα-target genes, whereas activated type I interferon (IFN) and IFN-induced genes (ISGs) in breast cancer cells. Consequently, iCARM1 potently suppressed breast cancer cell growth both in vitro and in vivo. The combination of iCARM1 with either endocrine therapy drugs or etoposide demonstrated synergistic effects in inhibiting the growth of breast tumors. In summary, targeting CARM1 by iCARM1 effectively suppresses breast tumor growth, offering a promising therapeutic approach for managing breast cancers in clinical settings.

Protective role of 17β-estradiol in alcohol-associated liver fibrosis is mediated by suppression of integrin signaling.

Alcohol-associated liver disease is a complex disease regulated by genetic and environmental factors such as diet and sex. The combination of high-fat diet and alcohol consumption has synergistic effects on liver disease progression. Female sex hormones are known to protect females from liver disease induced by high-fat diet. In contrast, they promote alcohol-mediated liver injury. We aimed to define the role of female sex hormones on liver disease induced by a combination of high-fat diet and alcohol. Wild-type and protein arginine methyltransferase (Prmt)6 knockout female mice were subjected to gonadectomy (ovariectomy, OVX) or sham surgeries and then fed western diet and alcohol in the drinking water. We found that female sex hormones protected mice from western diet/alcohol-induced weight gain, liver steatosis, injury, and fibrosis. Our data suggest that these changes are, in part, mediated by estrogen-mediated induction of arginine methyltransferase PRMT6. Liver proteome changes induced by OVX strongly correlated with changes induced by Prmt6 knockout. Using Prmt6 knockout mice, we confirmed that OVX-mediated weight gain, steatosis, and injury are PRMT6 dependent, while OVX-induced liver fibrosis is PRMT6 independent. Proteomic and gene expression analyses revealed that estrogen signaling suppressed the expression of several components of the integrin pathway, thus reducing integrin-mediated proinflammatory (Tnf, Il6) and profibrotic (Tgfb1, Col1a1) gene expression independent of PRMT6 levels. Integrin signaling inhibition using Arg-Gly-Asp peptides reduced proinflammatory and profibrotic gene expression in mice, suggesting that integrin suppression by estrogen is protective against fibrosis development. Taken together, estrogen signaling protects mice from liver disease induced by a combination of alcohol and high-fat diet through upregulation of Prmt6 and suppression of integrin signaling.

Induced Ablation of Prmt1 in Endothelial Cells Causes Endothelial Dysfunction Associated with Pulmonary Thromboembolic Hypertension

Endothelial cells (ECs) play vital roles in regulation of vascular homeostasis, vascular tone, leukocyte traffcking, and barrier function to ensure pulmonary function. Endothelial dysfunction is a key factor for the progression of pulmonary pathogenesis. Protein arginine methyltransferase 1 (Prmt1) catalyzes asymmetric di-methylation of substrates on arginine residues and is implicated in a variety of cellular processes, including cardiovascular function. In the current study, we examined the role of Prmt1 in endothelial function by using tamoxifen-inducible EC-specific Prmt1 ablation (KO) mice. EC-specific Prmt1 ablation in adult mice (KO) for 8 weeks led to lethality, concurrent with pulmonary hypertension and thromboembolism. The lung bulk RNA sequencing and single EC RNA sequencing analyses revealed that Prmt1 ablation increased inflammation, endothelial junction disruption, apoptosis, and fibrosis. Comprehensive analysis through bulk RNA and single cell RNA sequencing revealed that Prmt1 ablation in ECs triggers homeostatic disturbance accompanied by inflammation and endothelial dysfunction, associated with hyperactivation of NFkB and Stat signaling. In conclusion, the current study suggests that Prmt1 plays a key role in pulmonary endothelial function and vascular homeostasis via the suppression of NFkB-induced endothelial dysfunction. The National Research Foundation Grant funded by the Korean Government (MIST) (NRF-2022R1A2B5B02001482). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

PRMT1 promotes epigenetic reprogramming associated with acquired chemoresistance in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) carries a dismal prognosis due to therapeutic resistance. We show that PDAC cells undergo global epigenetic reprogramming to acquire chemoresistance, a process that is driven at least in part by protein arginine methyltransferase 1 (PRMT1). Genetic or pharmacological PRMT1 inhibition impairs adaptive epigenetic reprogramming and delays acquired resistance to gemcitabine and other common chemo drugs. Mechanistically, gemcitabine treatment induces translocation of PRMT1 into the nucleus, where its enzymatic activity limits the assembly of chromatin-bound MAFF/BACH1 transcriptional complexes. Cut&Tag chromatin profiling of H3K27Ac, MAFF, and BACH1 suggests a pivotal role for MAFF/BACH1 in global epigenetic response to gemcitabine, which is confirmed by genetically silencing MAFF. PRMT1 and MAFF/BACH1 signature genes identified by Cut&Tag analysis distinguish gemcitabine-resistant from gemcitabine-sensitive patient-derived xenografts of PDAC, supporting the PRMT1-MAFF/BACH1 epigenetic regulatory axis as a potential therapeutic avenue for improving the efficacy and durability of chemotherapies in patients of PDAC.

CARM1 hypermethylates the NuRD chromatin remodeling complex to promote cell cycle gene expression and breast cancer development.

Protein arginine methyltransferase CARM1 has been shown to methylate a large number of non-histone proteins, and play important roles in gene transcriptional activation, cell cycle progress, and tumorigenesis. However, the critical substrates through which CARM1 exerts its functions remain to be fully characterized. Here, we reported that CARM1 directly interacts with the GATAD2A/2B subunit in the nucleosome remodeling and deacetylase (NuRD) complex, expanding the activities of NuRD to include protein arginine methylation. CARM1 and NuRD bind and activate a large cohort of genes with implications in cell cycle control to facilitate the G1 to S phase transition. This gene activation process requires CARM1 to hypermethylate GATAD2A/2B at a cluster of arginines, which is critical for the recruitment of the NuRD complex. The clinical significance of this gene activation mechanism is underscored by the high expression of CARM1 and NuRD in breast cancers, and the fact that knockdown CARM1 and NuRD inhibits cancer cell growth in vitro and tumorigenesis in vivo. Targeting CARM1-mediated GATAD2A/2B methylation with CARM1 specific inhibitors potently inhibit breast cancer cell growth in vitro and tumorigenesis in vivo. These findings reveal a gene activation program that requires arginine methylation established by CARM1 on a key chromatin remodeler, and targeting such methylation might represent a promising therapeutic avenue in the clinic.

Identification of protein methyltransferases 5 associated with ferroptosis and immune cell infiltration of head and neck squamous cell carcinoma.

Head and neck tumors are malignant tumors that appear in the head and neck. Although much progress has been made in the treatment of head and neck tumors, many challenges remain. The prognosis of some advanced cases remains poor and survival and quality of life after treatment face certain limitations. Therefore, further research into the pathogenesis and treatment options for head and neck tumors is important in order to improve the prognosis and quality of life of patients. The Protein Arginine Methyltransferase (PRMT) family is a class of enzymes that are responsible for adding methyl groups to arginine residues in proteins. PRMT family members play important roles in regulating many cellular processes, such as transcriptional regulation, signaling, and cell cycle regulation. Recent studies have shown that the PRMT family also plays an important function in tumorigenesis and development. Here, we found that PRMT family members are significantly overexpressed in head and neck tumors and that PRMT5 may serve as an independent prognostic factor in head and neck tumors. We found that PRMT5-regulated differential genes were significantly enriched in tumor-associated signaling pathways such as IL-17 and p53. And we also found that the expression of PRMT5 in head and neck tumors was significantly correlated with immune cell infiltration, m6A as well as the expression of ferroptosis-related genes, and drug sensitivity. These results suggest that PRMT may play an important role in the development of head and neck tumors.

Tyrosine phosphorylation of CARM1 promotes its enzymatic activity and alters its target specificity

An important epigenetic component of tyrosine kinase signaling is the phosphorylation of histones, and epigenetic readers, writers, and erasers. Phosphorylation of protein arginine methyltransferases (PRMTs), have been shown to enhance and impair their enzymatic activity. In this study, we show that the hyperactivation of Janus kinase 2 (JAK2) by the V617F mutation phosphorylates tyrosine residues (Y149 and Y334) in coactivator-associated arginine methyltransferase 1 (CARM1), an important target in hematologic malignancies, increasing its methyltransferase activity and altering its target specificity. While non-phosphorylatable CARM1 methylates some established substrates (e.g. BAF155 and PABP1), only phospho-CARM1 methylates the RUNX1 transcription factor, on R223 and R319. Furthermore, cells expressing non-phosphorylatable CARM1 have impaired cell-cycle progression and increased apoptosis, compared to cells expressing phosphorylatable, wild-type CARM1, with reduced expression of genes associated with G2/M cell cycle progression and anti-apoptosis. The presence of the JAK2-V617F mutant kinase renders acute myeloid leukemia (AML) cells less sensitive to CARM1 inhibition, and we show that the dual targeting of JAK2 and CARM1 is more effective than monotherapy in AML cells expressing phospho-CARM1. Thus, the phosphorylation of CARM1 by hyperactivated JAK2 regulates its methyltransferase activity, helps select its substrates, and is required for the maximal proliferation of malignant myeloid cells.

Inhibition of PRMT5-mediated regulation of DKK1 sensitizes colorectal cancer cells to chemotherapy

The Dickkopf family proteins (DKKs) are strong Wnt signaling antagonists that play a significant role in colorectal cancer (CRC) development and progression. Recent work has shown that DKKs, mainly DKK1, are associated with the induction of chemoresistance in CRC and that DKK1 expression in cancer cells correlates with that of protein arginine N-methyltransferase 5 (PRMT5). This points to the presence of a regulatory loop between DKK1 and PRMT5. Herein, we addressed the question of whether PRMT5 contributes to DKK1 expression in CRC and hence CRC chemoresistance. Both in silico and in vitro approaches were used to explore the relationship between PRMT5 and different DKK members. Our data demonstrated that DKK1 expression is significantly upregulated in CRC clinical samples, KRAS-mutated CRC in particular and that the levels of DKK1 positively correlate with PRMT5 activation. Chromatin immunoprecipitation (ChIP) data indicated a possible epigenetic role of PRMT5 in regulating DKK1, possibly through the symmetric dimethylation of H3R8. Knockdown of DKK1 or treatment with the PRMT5 inhibitor CMP5 in combination with doxorubicin yielded a synergistic anti-tumor effect in KRAS mutant, but not KRAS wild-type, CRC cells. These findings suggest that PRMT5 regulates DKK1 expression in CRC and that inhibition of PRMT5 modulates DKK1 expression in such a way that reduces CRC cell growth.

Development of (2-(Benzyloxy)phenyl)methanamine Derivatives as Potent and Selective Inhibitors of CARM1 for the Treatment of Melanoma.

Coactivator-associated arginine methyltransferase 1 (CARM1), an important member of type I protein arginine methyltransferases (PRMTs), has emerged as a promising therapeutic target for various cancer types. In our previous study, we have identified a series of type I PRMT inhibitors, among which ZL-28-6 (6) exhibited increased activity against CARM1 while displaying decreased potency against other type I PRMTs. In this work, we conducted chemical modifications on compound 6, resulting in a series of (2-(benzyloxy)phenyl)methanamine derivatives as potent inhibitors of CARM1. Among them, compound 17e displayed remarkable potency and selectivity for CARM1 (IC50 = 2 ± 1 nM), along with notable antiproliferative effects against melanoma cell lines. Cellular thermal shift assay and western blot experiments confirmed that compound 6 effectively targets CARM1 within cells. Furthermore, compound 17e displayed good antitumor efficacy in a melanoma xenograft model, indicating that this compound warrants further investigation as a potential anticancer agent.

PRMT4 interacts with NCOA4 to inhibit ferritinophagy in cisplatin-induced acute kidney injury.

Cisplatin-induced acute kidney injury (AKI) is commonly seen in the clinical practice, and ferroptosis, a type of non-apoptotic cell death, plays a pivotal role in it. Previous studies suggested that protein arginine methyltransferase 4 (PRMT4) was incorporated in various bioprocesses, but its role in renal injuries has not been investigated. Our present study showed that PRMT4 was highly expressed in renal proximal tubular cells, and it was downregulated in cisplatin-induced AKI. Besides, genetic disruption of PRMT4 exacerbated, while its overexpression attenuated, cisplatin-induced redox injuries in renal proximal epithelia. Mechanistically, our work showed that PRMT4 interacted with NCOA4 to inhibit ferritinophagy, a type of selective autophagy favoring lipid peroxidation to accelerate ferroptosis. Taken together, our study demonstrated that PRMT4 interacted with NCOA4 to attenuate ferroptosis in cisplatin-induced AKI, suggesting that PRMT4 might present as a new therapeutic target for cisplatin-related nephropathy.

Protein Arginine Methyltransferases in Pancreatic Ductal Adenocarcinoma: New Molecular Targets for Therapy.

Pancreatic ductal adenocarcinoma (PDAC) is a lethal malignant disease with a low 5-year overall survival rate. It is the third-leading cause of cancer-related deaths in the United States. The lack of robust therapeutics, absence of effective biomarkers for early detection, and aggressive nature of the tumor contribute to the high mortality rate of PDAC. Notably, the outcomes of recent immunotherapy and targeted therapy against PDAC remain unsatisfactory, indicating the need for novel therapeutic strategies. One of the newly described molecular features of PDAC is the altered expression of protein arginine methyltransferases (PRMTs). PRMTs are a group of enzymes known to methylate arginine residues in both histone and non-histone proteins, thereby mediating cellular homeostasis in biological systems. Some of the PRMT enzymes are known to be overexpressed in PDAC that promotes tumor progression and chemo-resistance via regulating gene transcription, cellular metabolic processes, RNA metabolism, and epithelial mesenchymal transition (EMT). Small-molecule inhibitors of PRMTs are currently under clinical trials and can potentially become a new generation of anti-cancer drugs. This review aims to provide an overview of the current understanding of PRMTs in PDAC, focusing on their pathological roles and their potential as new therapeutic targets.

Loss-of-function mutation in PRMT9 causes abnormal synapse development by dysregulation of RNA alternative splicing

Protein arginine methyltransferase 9 (PRMT9) is a recently identified member of the PRMT family, yet its biological function remains largely unknown. Here, by characterizing an intellectual disability associated PRMT9 mutation (G189R) and establishing a Prmt9 conditional knockout (cKO) mouse model, we uncover an important function of PRMT9 in neuronal development. The G189R mutation abolishes PRMT9 methyltransferase activity and reduces its protein stability. Knockout of Prmt9 in hippocampal neurons causes alternative splicing of ~1900 genes, which likely accounts for the aberrant synapse development and impaired learning and memory in the Prmt9 cKO mice. Mechanistically, we discover a methylation-sensitive protein–RNA interaction between the arginine 508 (R508) of the splicing factor 3B subunit 2 (SF3B2), the site that is exclusively methylated by PRMT9, and the pre-mRNA anchoring site, a cis-regulatory element that is critical for RNA splicing. Additionally, using human and mouse cell lines, as well as an SF3B2 arginine methylation-deficient mouse model, we provide strong evidence that SF3B2 is the primary methylation substrate of PRMT9, thus highlighting the conserved function of the PRMT9/SF3B2 axis in regulating pre-mRNA splicing.

PRMT-7/PRMT7 activates HLH-30/TFEB to guard plasma membrane integrity compromised by bacterial pore-forming toxins

ABSTRACT Bacterial pore-forming toxins (PFTs) that disrupt host plasma membrane integrity (PMI) significantly contribute to the virulence of various pathogens. However, how host cells protect PMI in response to PFT perforation in vivo remains obscure. Previously, we demonstrated that the HLH-30/TFEB-dependent intrinsic cellular defense (INCED) is elicited by PFT to maintain PMI in Caenorhabditis elegans intestinal epithelium. Yet, the molecular mechanism for the full activation of HLH-30/TFEB by PFT remains elusive. Here, we reveal that PRMT-7 (protein arginine methyltransferase-7) is indispensable to the nuclear transactivation of HLH-30 elicited by PFTs. We demonstrate that PRMT-7 participates in the methylation of HLH-30 on its RAG complex binding domain to facilitate its nuclear localization and activation. Moreover, we showed that PRMT7 is evolutionarily conserved to regulate TFEB cellular localization and repair plasma damage caused by PFTs in human intestinal cells. Together, our observations not only unveil a novel PRMT-7/PRMT7-dependent post-translational regulation of HLH-30/TFEB but also shed insight on the evolutionarily conserved mechanism of the INCED against PFT in metazoans.

The antidepressant effects of protein arginine methyltransferase 2 involve neuroinflammation

Protein arginine methyltransferase (PRMT) 2 catalyzes the methylation of arginine residues in histones. Depression is associated with histone methylation; however, more comprehensive research is needed on how PRMT2 regulates depression. The present study aimed to investigate the effects and possible mechanism(s) of PRMT2 overexpression on depression-like behavior induced by chronic unpredictable mild stress (CUMS) in rats, and whether lentivirus-mediated PRMT2 overexpression in the hippocampus suppresses depression-like behavior. Furthermore, the PRMT2 inhibitor MS023 was administered to the animals to investigate whether the antidepressant effect of PRMT2 overexpression could be reversed. Behavioral experiments were performed to detect depression-like behavior in rats. Western blotting was used to determine protein expression levels of PRMT2, histone H3R8 asymmetric dimethylation (H3R8me2a), inducible nitric oxide synthase (iNOS), and arginase 1 (Arg1) in rat hippocampal tissues. Hippocampal microglia and PRMT2 were stained using immunofluorescence techniques. Enzyme-linked immunosorbent assay was used to determine the levels of various inflammatory factors in rat hippocampal tissue. Results of analysis revealed that PRMT2 overexpression in the hippocampus exerted an antidepressant effect. PRMT2 overexpression in the hippocampus reduced the proportion of activated microglia in the hippocampus, upregulated Arg1 and H3R8me2a expression, and downregulated iNOS expression. PRMT2 overexpression in the hippocampus inhibited the release of pro-inflammatory factors and promoted the release of anti-inflammatory factors. In summary, PRMT2 overexpression in the hippocampus promoted the conversion of microglia from the M1 to M2 type, resulting in an antidepressant effect. These results suggest that PRMT2 may be a potential therapeutic target to prevent and treat depression.

EGR3 reduces podocyte inflammatory damage in obesity related glomerulopathy by inhibiting the PRMT1/p-STAT3 pathway.

Obesity related glomerulopathy (ORG) is induced by obesity, but the pathogenesis remains unclear. This study aims to investigate the expression of early growth response protein 3 (EGR3) in the renal cortex tissues of ORG patients and high-fat diet-induced obese mice, and to further explore the molecular mechanism of EGR3 in inhibiting palmitic acid (PA) induced human podocyte inflammatory damage. Renal cortex tissues were collected from ORG patients (n=6) who have been excluded from kidney damage caused by other diseases and confirmed by histopathology, and from obese mice induced by high-fat diet (n=10). Human and mouse podocytes were intervened with 150 μmol/L PA for 48 hours. EGR3 was overexpressed or silenced in human podocytes. Enzyme linked immunosorbent assay (ELISA) was used to detcet the levels of interleukin-6 (IL-6) and interleukin-1β (IL-1β). Real-time RT-PCR was used to detect the mRNA expressions of EGR3, podocytes molecular markers nephrosis 1 (NPHS1), nephrosis 2 (NPHS2), podocalyxin (PODXL), and podoplanin (PDPN). RNA-seq was performed to detect differentially expressed genes (DEGs) after human podocytes overexpressing EGR3 and treated with 150 μmol/L PA compared with the control group. Co-immunoprecipitation (Co-IP) combined with liquid chromatography tandem mass spectrometry (LC-MS) was used to detect potential interacting proteins of EGR3 and the intersected with the RNA-seq results. Co-IP confirmed the interaction between EGR3 and protein arginine methyltransferases 1 (PRMT1), after silencing EGR3 and PRMT1 inhibitor intervention, the secretion of IL-6 and IL-1β in PA-induced podocytes was detected. Western blotting was used to detect the expression of phosphorylated signal transducer and activator of transcription 3 (p-STAT3) after overexpression or silencing of EGR3. EGR3 was significantly upregulated in renal cortex tissues of ORG patients and high-fat diet-induced obese mice (both P<0.01). In addition, after treating with 150 μmol/L PA for 48 hours, the expression of EGR3 in human and mouse podocytes was significantly upregulated (both P<0.05). Overexpression or silencing of EGR3 in human podocytes inhibited or promoted the secretion of IL-6 and IL-1β in the cell culture supernatant after PA intervention, respectively, and upregulated or downregulated the expression of NPHS1, PODXL, NPHS2,and PDPN (all P<0.05). RNA-seq showed a total of 988 DEGs, and Co-IP+LC-MS identified a total of 238 proteins that may interact with EGR3. Co-IP confirmed that PRMT1 was an interacting protein with EGR3. Furthermore, PRMT1 inhibitors could partially reduce PA-induced IL-6 and IL-1β secretion after EGR3 silencing in human podocytes (both P<0.05). Overexpression or silencing of EGR3 negatively regulated the expression of PRMT1 and p-STAT3. EGR3 may reduce ORG podocyte inflammatory damage by inhibiting the PRMT1/p-STAT3 pathway.