Protein Arginine Methyltransferase Research Articles

Prmt5 is essential for intestinal stem cell maintenance and homeostasis

Intestinal homeostasis relies on the continuous renewal of intestinal stem cells (ISCs), which could be epigenetically regulated. While protein arginine methyltransferase 5 (Prmt5) is known to play a key role in multiple organs as an epigenetic modifier, its specific function in maintaining intestinal homeostasis remains to be elucidated. Here, we show that Prmt5 is highly expressed in mouse crypts. The deletion of Prmt5 results in ISCs deficiency, ectopic localization of Paneth cells, and spontaneous colitis. Mechanistically, Prmt5 sustains a high level of H3K27ac accumulation by inhibiting Hdac9 expression in the intestinal epithelium, and maintains the stemness of ISCs in a cell-autonomous manner. Notably, inhibition of histone deacetylases can rescue both self‐renewal and differentiation capacities of Prmt5‐depleted ISCs. These findings highlight Prmt5 as a critical regulator in intestinal epithelium development and tissue homeostasis.

Assessment of PRMT6-dependent alternative splicing in pluripotent and differentiating NT2/D1 cells.

Protein arginine methyltransferase 6 (PRMT6) is a well-characterized epigenetic regulator that methylates histone H3 at arginine 2 (H3R2me2a) in both promoter and enhancer regions, thereby modulating transcriptional initiation. We report here that PRMT6 also regulates gene expression at the post-transcriptional level in the neural pluripotent state and during neuronal differentiation of NT2/D1 cells. PRMT6 knockout causes widespread alternative splicing changes in NT2/D1 cells, most frequently cassette exon alterations. Most of the PRMT6-dependent splicing targets are not transcriptionally affected by the enzyme and regulated in an H3R2me2a-independent manner. However, for a small subset of splicing events, the PRMT6-mediated deposition of H3R2me2a overlaps with the splice site, suggesting a potential dual function in both transcriptional and co-/post-transcriptional regulation. The splicing targets of PRMT6 include ribosomal proteins, splicing factors, and chromatin-modifying enzymes such as PRMT4, DNMT3B, and ASH2L, some of which are associated with differentiation decisions. Taken together, our results in NT2/D1 cells show that PRMT6 exerts predominantly H3R2me2a-independent functions in RNA splicing, which may contribute to pluripotency and neuronal identity.

Arginine methyltransferase PRMT1 promotes ferroptosis through EGR1/GLS2 axis in sepsis-related acute lung injury

Acute lung injury (ALI), a frequent and severe complication of sepsis, is associated with significant mortality rates. Previous studies indicated that GLS2 plays a key role in promoting ferroptosis. However, its underlying mechanisms remain unclear. Here we show, there were elevated ferroptosis and increased expression levels of protein arginine methyltransferase 1 (PRMT1), early growth response 1 (EGR1), and glutaminase 2 (GLS2) in both in vitro and in vivo ALI models. Additionally, EGR1 was found to induce the transcription of GLS2, thereby promoting ferroptosis. We also discovered that the protein level of EGR1 was increased through enhanced stability, facilitated by PRMT1-mediated arginine methylation, and reduced ubiquitination degradation regulated by neural precursor cell expressed developmentally down-regulated protein 4 like (NEDD4L). The in vivo results confirmed that the knockdown of PRMT1 suppressed ferroptosis via the EGR1/GLS2 axis. Our findings suggest that PRMT1-mediated stabilization of EGR1 promoted sepsis induced ALI via GLS2, highlighting the therapeutic potential of targeting PRMT1 or EGR1 in the treatment of sepsis-induced ALI.

PRMT5 Maintains Homeostasis of the Intestinal Epithelium by Modulating Cell Proliferation and Survival.

Intestinal homeostasis is sustained by self-renewal of intestinal stem cells, which continuously divide and produce proliferative transit-amplifying (TA) and progenitor cells. Protein arginine methyltransferases 5 (PRMT5) plays a crucial role in regulating homeostasis of various mammalian tissues. However, its function in intestinal homeostasis remains elusive. In this study, conditional knockout of Prmt5 in the mouse intestinal epithelium leads to a reduction in stem cell population, suppression of cell proliferation, and increased cell apoptosis within the intestinal crypts, accompanied with shortened gut length, decreased mouse body weight, and eventual animal mortality. Additionally, Prmt5 deletion or its enzymatic inhibition in intestinal organoids in vitro also shows resembling cellular phenotypes. Methylome profiling identifies 90 potential Prmt5 substrates, which are involved in RNA-related biological processes and cell division. Consistently, Prmt5 depletion in intestinal organoids leads to aberrant alternative splicing in a subset of genes related to the mitotic cell cycle. Furthermore, Prmt5 loss triggers p53-mediated apoptosis in the intestinal epithelium. Collectively, the findings uncover an indispensable role of PRMT5 in promoting cell proliferation and survival, as well as maintaining stem cells in the gut epithelium.

PRMT5 Inhibition Enhances Therapeutic Efficacy of Cisplatin via Mediating miR-29b-3p-Mcl-1 Expression in Lung Adenocarcinoma.

Cisplatin is one of the front-line therapeutic agents used to treat cancers, while drug resistance is a great obstacle to anti-tumor efficiency. Protein arginine methyltransferase 5 (PRMT5) has been identified as a promoter of tumorigenesis, motility, and invasion. Inhibiting PRMT5 reduced hypoxia-induced carboplatin resistance in lung adenocarcinoma (LUAD). However, the specific relationship between PRMT5 and cisplatin (CDDP) warrants further investigation. Our research revealed that PRMT5 inhibitor C9 enhanced CDDP chemosensitivity by suppressing proliferation and promoting apoptosis in LUAD cells. Through examining pro-apoptotic proteins regulated by PRMT5, we identified that Mcl-1 played a significant role in PRMT5-mediated CDDP chemosensitivity. Furthermore, PRMT5 regulated Mcl-1 expression through mediating miR-29b-3p. In vivo, our research presented that C9 increased CDDP chemosensitivity in LUAD xenografts. All in all, our data raised an interesting possibility that epigenetic reprogramming was associated with chemosensitivity. PRMT5 inhibitor C9 improved CDDP effectiveness in LUAD cells by inhibiting Mcl-1 expression via miR-29b-3p, thereby modulating cellular proliferation and apoptosis.

Protein arginine methyltransferase 7 linked to schizophrenia through regulation of neural progenitor cell proliferation and differentiation

Protein arginine methyltransferase 7 linked to schizophrenia through regulation of neural progenitor cell proliferation and differentiation

Targeting Protein Arginine Methyltransferases in Breast Cancer: Promising Strategies

Targeting Protein Arginine Methyltransferases in Breast Cancer: Promising Strategies

Protein Arginine Methyltransferase 1: A Multi-Purpose Player in the Development of Cancer and Metabolic Disease

Protein arginine methyltransferase 1 (PRMT1) is the main PRMT family member involved in the formation of monomethylarginine and asymmetric dimethylarginine on its protein substrates. Many protein substrates of PRMT1 are key mediators of cell proliferation and oncogenesis. As such, the function of PRMT1 has been most prominently investigated in the context of cancer development. However, recent in vitro and in vivo studies have highlighted that PRMT1 may also promote metabolic disorders. With the current review, we aim to present an in-depth overview of how PRMT1 influences epigenetic modulation, transcriptional regulation, DNA damage repair, and signal transduction in cancer. Furthermore, we summarize the current knowledge regarding the role of PRMT1 in metabolic reprogramming, lipid metabolism, and glucose metabolism and describe the association of PRMT1 with numerous metabolic pathologies such as obesity, liver disease, and type 2 diabetes. It has become apparent that inhibiting the function of PRMT1 will likely serve as the most beneficial therapeutic approach, since several PRMT1 inhibitors have already been shown to exert positive effects on both cancer and metabolic disease in preclinical settings. However, pharmacological PRMT1 inhibition has not yet been shown to be therapeutically effective in clinical studies.

Phase Ib study of PRT543, an oral protein arginine methyltransferase 5 (PRMT5) inhibitor, in patients with advanced splicing factor-mutant myeloid malignancies.

Phase Ib study of PRT543, an oral protein arginine methyltransferase 5 (PRMT5) inhibitor, in patients with advanced splicing factor-mutant myeloid malignancies.

Nutrient control of splice site selection contributes to methionine addiction of cancer.

Many cancer cells depend on exogenous methionine for proliferation, whereas non-tumorigenic cells can divide in media supplemented with the metabolic precursor homocysteine. This phenomenon is known as methionine dependence of cancer or methionine addiction. The underlying mechanisms driving this cancer-specific metabolic addiction are poorly understood. Here we find that methionine dependence is associated with severe dysregulation of pre-mRNA splicing. We used triple-negative breast cancer cells and their methionine-independent derivatives R8 to compare RNA expression profiles in methionine and homocysteine growth media. The data set was also analyzed for alternative splicing. When tumorigenic cells were cultured in homocysteine medium, cancer cells failed to efficiently methylate the spliceosomal snRNP component SmD1, which resulted in reduced binding to the Survival-of-Motor-Neuron protein SMN leading to aberrant splicing. These effects were specific for cancer cells as neither Sm protein methylation nor splicing fidelity was affected when non-tumorigenic cells were cultured in homocysteine medium. Sm protein methylation is catalyzed by Protein Arginine Methyl Transferase 5 (Prmt5). Reducing methionine concentrations in the culture medium sensitized cancer cells to Prmt5 inhibition supporting a mechanistic link between methionine dependence of cancer and splicing. Our results link nutritional demands to splicing changes and thereby provide a link between the cancer-specific metabolic phenomenon, described as methionine addiction over 40 years ago, with a defined cellular pathway that contributes to cancer cell proliferation.

Blockade of A2AR improved brain perfusion and cognitive function in a mouse model of Alzheimer's disease.

Alzheimer's disease (AD) is a neurodegenerative disorder that affects more than 6.2 million Americans aged 65 and older, particularly women. Along with AD's main hallmarks (formation of β-amyloid plaques and tau neurofibrillary tangles), there are vascular alterations that occurs in AD pathology. Adenosine A2 receptor (A2AR) is one of the key factors of brain vascular autoregulation and is overexpressed in AD patients. Our previous findings suggest that protein arginine methyltransferase 4 (PRMT4) is overexpressed in AD, which leads to decrease in cerebral blood flow in aged female 3xTg mice. We aimed to investigate the mechanism behind A2AR signaling in the regulation of brain perfusion and blood-brain barrier integrity in age and sex-dependent 3xTg mice, and if it is related to PRMT4. Istradefylline, a highly selective A2AR antagonist, was used to modulate A2AR signaling. Aged female 3xTg and C57BL/6J mice were evaluated for brain perfusion (via laser speckle) and cognitive function (via open field, T-maze and novel object recognition). Our results suggest that modulation of A2AR signaling in aged female 3xTg increased cerebral perfusion by decreasing PRMT4 expression, restored the levels of APP and tau, maintained blood-brain barrier integrity by maintaining the expression of tight junction proteins, and preserved functional learning/memory.

Discovery of novel PRMT1 inhibitors: a combined approach using AI classification model and traditional virtual screening.

Protein arginine methyltransferases (PRMTs) play crucial roles in gene regulation, signal transduction, mRNA splicing, DNA repair, cell differentiation, and embryonic development. Due to its significant impact, PRMTs is a target for the prevention and treatment of various diseases. Among the PRMT family, PRMT1 is the most abundant and ubiquitously expressed in the human body. Although extensive research has been conducted on PRMT1, the reported inhibitors have not successfully passed clinical trials. In this study, deep learning was employed to analyze the characteristics of existing PRMTs inhibitors and to construct a classification model for PRMT1 inhibitors. Through a classification model and molecular docking, a series of potential PRMT1 inhibitors were identified. The representative compound (compound 156) demonstrates stable binding to the PRMT1 protein by molecular hybridization, molecular dynamics simulations, and binding free energy analyses. The study discovered novel scaffolds for potential PRMT1 inhibitors.

PRMT5 Inhibition Reduces Hyperinflammation in a Murine Model of Secondary Hemophagocytic Lymphohistiocytosis (HLH).

Hemophagocytic lymphohistiocytosis (HLH) is a rare but aggressive and potentially lethal hyperinflammatory syndrome characterized by pathologic immune activation and excessive production of proinflammatory cytokines leading to tissue damage and multisystem organ failure. There is an urgent need for the discovery of novel targets and development of therapeutic strategies to treat this rare but deadly syndrome. Protein Arginine Methyltransferase 5 (PRMT5) mediates T cell-based inflammatory responses, making it a potential actionable target for the treatment of HLH. Using CPG-1826 and anti-IL10R antibody, we induced murine secondary HLH in vivo with a marked expansion of splenic myeloid cell subsets and concurrent reduction of T and NK cell populations. PRMT5 expression was significantly upregulated in splenic T and NK lymphocytes as well as monocytes and dendritic cells in mice with HLH (p<0.05). Treatment with PRT382, a potent and selective PRMT5 inhibitor, significantly reduced physical signs of secondary HLH, including splenomegaly, hepatomegaly and anemia (p<0.0001 in each case), when compared to untreated mice. Inflammatory cytokines known to drive hyperinflammation in HLH, including IFNγ and IL-6 were reduced to healthy levels with PRT382 treatment (p>0.999 for both). PRT382 treatment also reduced the expansion of myeloid cell populations (p<0.0001) in mice with HLH, compared to untreated mice, while restoring T and NK cell numbers (p<0.001 for both). These results identify PRMT5 as a promising target for the management of secondary HLH and justify further exploration in this and other models of hyperinflammation.

Update on the Progress of Musashi-2 in Malignant Tumors.

Since the discovery of the Musashi (MSI) protein, its ability to affect the mitosis of Drosophila progenitor cells has garnered significant interest among scientists. In the following 20 years, it has lived up to expectations. A substantial body of evidence has demonstrated that it is closely related to the development, metastasis, migration, and drug resistance of malignant tumors. In recent years, research on the MSI protein has advanced, and many novel viewpoints and drug resistance attempts have been derived; for example, tumor protein p53 mutations and MSI-binding proteins lead to resistance to protein arginine N-methyltransferase 5-targeted therapy in lymphoma patients. Moreover, the high expression of MSI2 in pancreatic cancer might suppress its development and progression. As a significant member of the MSI family, MSI2 is closely associated with multiple malignant tumors, including hematological disorders, common abdominal tumors, and other tumor types (e.g., glioblastoma, breast cancer). MSI2 is highly expressed in the majority of tumors and is related to a poor disease prognosis. However, its specific expression levels and regulatory mechanisms may differ based on the tumor type. This review summarizes the research progress related to MSI2 in recent years, including its occurrence, migration mechanism, and drug resistance, as well as the prospect of developing tumor immunosuppressants and biomarkers.

PRMT6 promotes colorectal cancer progress via activating MYC signaling

Colorectal cancer (CRC) remains a major global health challenge, with high rates of incidence and mortality. This study investigates the role of protein arginine methyltransferase 6 (PRMT6) as an oncogene in CRC and its mechanistic involvement in tumor progression. We found that PRMT6 is significantly overexpressed in CRC tissues compared to adjacent normal tissues and is associated with poorer patient survival. Functional assays demonstrated that PRMT6 promotes CRC cell proliferation, migration, and invasion. Mechanistically, PRMT6 enhances MYC signaling by stabilizing c-MYC through mono-methylation at arginine 371, which inhibits c-MYC poly-ubiquitination and subsequent degradation. This post-translational modification is crucial for PRMT6-induced cancer cell proliferation. Xenograft models further validated that PRMT6 knockdown results in reduced tumor growth and decreased c-MYC levels. Our findings highlight PRMT6 as a key regulator of c-MYC stability and CRC progression, suggesting that targeting PRMT6 or its effects on c-MYC could offer a promising strategy for CRC treatment.

Biomedical Effects of Protein Arginine Methyltransferase Inhibitors.

Protein arginine methyltransferases (PRMTs) are enzymes that catalyze the methylation of arginine residues in eukaryotic proteins, playing critical roles in modulating diverse cellular processes. The importance of PRMTs in the incidence and progression of a wide range of diseases, particularly cancers, such as breast, liver, lung, colorectal cancer, lymphoma, leukemia, and acute myeloid leukemia (AML) is increasingly recognized. This underscores the critical need for the development of effective PRMT inhibitors as therapeutic intervention. The field of PRMT inhibitors is in the rapidly growing phase and it is necessary to conduct a summative review of how the so-far developed inhibitors impact PRMT functions and cellular physiology. Our review aims to summarize molecular action mechanisms of these PRMT inhibitors and particularly elaborate their triggered biomedical effects. We delineate the cellular phenotype consequences of select PRMT inhibitors across various disease models, thereby providing an understanding of the pharmacological mechanisms underpinning PRMT inhibition. The promising effects of PRMT5 inhibitors in targeted therapy of MTAP-deleted cancers is particularly highlighted. At last, we provide a perspective on the challenges and further opportunities of developing and applying novel PRMT inhibitors for clinical advancement.

Baicalein attenuates ovalbumin-induced allergic rhinitis through the activation of nuclear receptor subfamily 4 group a member 1.

Baicalein, one of the major active flavonoids found in Scutellaria baicalensis, has been revealed to exhibit potent anti-inflammatory properties in allergic airway inflammation. This study aimed to explore the role of baicalein and its relevant mechanism in the treatment of allergic rhinitis (AR). The bioinformatics tools were used to predict the targets of baicalein and AR-related genes. AR mice were induced by ovalbumin (OVA) and treated with lentivirus-encapsulated knockdown of nuclear receptor subfamily 4 group A member 1 (NR4A1) or protein arginine N-methyltransferase 1 (PRMT1) plasmids and baicalein. IL-4/IL-13-induced human nasal mucosal epithelial cells (HNEpC) were transfected with knockdown of NR4A1 or PRMT1 plasmids and baicalein treatment. Baicalein alleviated AR-like symptoms and reduced the levels of immunoglobulin E, histamine, and LTC4 in serum and IL-4, IL-25, and IL-33 concentrations in nasal lavage fluids of mice induced with OVA by increasing NR4A1 expression. NR4A1 blocked the NFκB/p65 pathway by mediating transcriptional repression of PRMT1. Knockdown of PRMT1 overturned the effects of NR4A1 knockdown on IL-4/IL-13-induced HNEpC and OVA-induced mice. Collectively, these findings provide evidence that baicalein activation of NR4A1 mediates transcriptional repression of PRMT1 and relieves AR in mice by blocking the NFκB/p65 pathway.

PRMT5 inhibition has a potent anti-tumor activity against adenoid cystic carcinoma of salivary glands

BackgroundAdenoid cystic carcinoma (ACC) is a rare glandular malignancy, commonly originating in salivary glands of the head and neck. Given its protracted growth, ACC is usually diagnosed in advanced stage. Treatment of ACC is limited to surgery and/or adjuvant radiotherapy, which often fails to prevent disease recurrence, and no FDA-approved targeted therapies are currently available. As such, identification of new therapeutic targets specific to ACC is crucial for improved patients’ outcomes.MethodsAfter thoroughly evaluating the gene expression and signaling patterns characterizing ACC, we applied PandaOmics (an AI-driven software platform for novel therapeutic target discovery) on the unique transcriptomic dataset of 87 primary ACCs. Identifying protein arginine methyl transferase 5 (PRMT5) as a putative candidate with the top-scored druggability, we next determined the applicability of PRMT5 inhibitors (PRT543 and PRT811) using ACC cell lines, organoids, and patient derived xenograft (PDX) models. Molecular changes associated with response to PRMT5 inhibition and anti-proliferative effect of the combination therapy with lenvatinib was then analyzed.ResultsUsing a comprehensive AI-powered engine for target identification, PRMT5 was predicted among potential therapeutic target candidates for ACC. Here we show that monotherapy with selective PRMT5 inhibitors induced a potent anti-tumor activity across several cellular and animal models of ACC, which was paralleled by downregulation of genes associated with ACC tumorigenesis, including MYB and MYC (the recognized drivers of ACC progression). Furthermore, as a subset of genes targeted by lenvatinib is upregulated in ACC, we demonstrate that addition of lenvatinib enhanced the growth inhibitory effect of PRMT5 blockade in vitro, suggesting a potential clinical benefit for patients expressing lenvatinib favorable molecular profile.ConclusionTaken together, our study underscores the role of PRMT5 in ACC oncogenesis and provides a strong rationale for the clinical development of PRMT5 inhibitors as a targeted monotherapy or combination therapy for treatment of patients with this rare disease, based on the analysis of their underlying molecular profile.

Discovery of Potent, Highly Selective, and Orally Bioavailable MTA Cooperative PRMT5 Inhibitors with Robust In Vivo Antitumor Activity.

Protein arginine methyltransferase 5 (PRMT5), which catalyzes the symmetric dimethylation of arginine residues on target proteins, plays a critical role in gene expression regulation, RNA processing, and signal transduction. Aberrant PRMT5 activity has been implicated in cancers and other diseases, making it a potential therapeutic target. Here, we report the discovery of a methylthioadenosine (MTA) cooperative PRMT5 inhibitor. Compound 20 exhibited strong antiproliferation activity in multiple MTAP-deleted cancer cell lines, excellent selectivity over MTAP wild-type cell lines, as well as satisfactory oral pharmacokinetic properties over various preclinical species. Notably, compound 20 demonstrated a dose-dependent reduction of symmetric dimethylarginine (SDMA) expression in the LU99 cell line and robust in vivo antitumor activity in the LU99 subcutaneous model.

Substrate adaptors are flexible tethering modules that enhance substrate methylation by the arginine methyltransferase PRMT5.

Protein arginine methyltransferase (PRMT) 5 is an essential arginine methyltransferase responsible for the majority of cellular symmetric dimethyl-arginine (SDMA) marks. PRMT5 uses substrate adaptors such as pICln, RIOK1, and COPR5, to recruit and methylate a wide range of substrates. Although the substrate adaptors play important roles in substrate recognition, how they direct PRMT5 activity towards specific substrates remains incompletely understood. Using biochemistry and cryogenic electron microscopy (cryo-EM), we show that these adaptors compete for the same binding site on PRMT5. We find that substrate adaptor and substrate complexes are bound to PRMT5 through two peptide motifs, enabling these adaptors to act as flexible tethering modules to enhance substrate methylation. Taken together, our results shed structural and mechanistic light on the PRMT5 substrate adaptor function and the biochemical nature of PRMT5 interactors.