Protein arginine methyltransferase 1 contributes to the development of allergic rhinitis by promoting the production of epithelial-derived cytokines

Oligomerization of protein arginine methyltransferase 1 and its effect on methyltransferase activity and substrate specificity

Proper protein arginine methylation by protein arginine methyltransferase 1 (PRMT1) is critical for maintaining cellular health, while dysregulation is often associated with disease. How the activity of PRMT1 is regulated is therefore paramount, but is not clearly understood. Several studies have observed higher order oligomeric species of PRMT1, but it is unclear if these exist at physiological concentrations and there is confusion in the literature about how oligomerization affects activity. We therefore sought to determine which oligomeric species of PRMT1 are physiologically relevant, and quantitatively correlate activity with specific oligomer forms. Through quantitative western blotting, we determined that concentrations of PRMT1 available in a variety of human cell lines are in the sub-micromolar to low micromolar range. Isothermal spectral shift binding data were modeled to a monomer/dimer/tetramer equilibrium with an EC50 for tetramer dissociation of ~20 nM. A combination of sedimentation velocity and Native polyacrylamide gel electrophoresis experiments directly confirmed that the major oligomeric species of PRMT1 at physiological concentrations would be dimers and tetramers. Surprisingly, the methyltransferase activity of a dimeric PRMT1 variant is similar to wild type, tetrameric PRMT1 with some purified substrates, but dimer and tetramer forms of PRMT1 show differences in catalytic efficiencies and substrate specificity for other substrates. Our results define an oligomerization paradigm for PRMT1, show that the biophysical characteristics of PRMT1 are poised to support a monomer/dimer/tetramer equilibrium in vivo, and suggest that the oligomeric state of PRMT1 could be used to regulate substrate specificity.

The role of protein arginine N-methyltransferases in inflammation

Protein arginine methyltransferases (PRMTs) promote the methylation of numerous proteins at their arginine residues. An increasing number of publications have suggested that dysregulation of PRMTs participates in various human diseases, such as cardiovascular diseases, cancer, diabetes and neurodegenerative disorders. Inflammation is one normal response to infection or injury by immune system, which can keep body homeostasis. Emerging data reveal that inflammation is associated with the development of numerous diseases. Moreover, accumulated evidence proves that PRMTs have been characterized to regulate inflammation in various diseases. In this review article, we delineate the function and molecular mechanism of PRMTs in regulation of inflammation in current literature. Moreover, we discuss that targeting PRMTs by its inhibitors and compounds could have therapeutic potential.

PRMT1 in human neoplasm: cancer biology and potential therapeutic target

Protein arginine methyltransferase 1 (PRMT1), the predominant type I protein arginine methyltransferase, plays a crucial role in normal biological functions by catalyzing the methylation of arginine side chains, specifically monomethylarginine (MMA) and asymmetric dimethylarginine (ADMA), within proteins. Recent investigations have unveiled an association between dysregulated PRMT1 expression and the initiation and progression of tumors, significantly impacting patient prognosis, attributed to PRMT1's involvement in regulating various facets of tumor cell biology, including DNA damage repair, transcriptional and translational regulation, as well as signal transduction. In this review, we present an overview of recent advancements in PRMT1 research across different tumor types, with a specific focus on its contributions to tumor cell proliferation, metastasis, invasion, and drug resistance. Additionally, we expound on the dynamic functions of PRMT1 during distinct stages of cancer progression, elucidating its unique regulatory mechanisms within the same signaling pathway and distinguishing between its promotive and inhibitory effects. Importantly, we sought to provide a comprehensive summary and analysis of recent research progress on PRMT1 in tumors, contributing to a deeper understanding of its role in tumorigenesis, development, and potential treatment strategies.

Hyperforin modulates MAPK/CCL11 signaling to reduce the inflammatory response of nasal mucosal epithelial cells caused by allergic rhinitis by targeting BCL6

Hyperforin is a type of bicyclic tetraketone with four isoprenoid chains extracted from Hypericum perforatum L. that has multiple biological activities such as anti-diabetes, antitumor and anti-inflammation. However, the role and potential mechanism of hyperforin in allergic rhinitis (AR) remains to be clarified. In the present study, cell viability was analyzed using Cell Counting Kit-8 assay, while inflammation was detected using ELISA and reverse transcription-quantitative PCR. Epithelial cell barrier damage was measured using western blotting and immunofluorescence staining. The expression levels of B-cell lymphoma 6 (BCL6) and the p38 MAPK/C-C motif chemokine 11 (CCL11) pathway were detected using western blotting. In addition, the association between hyperforin and BCL6 was analyzed by SWISS TargetPrediction, DisGeNET, Gene Ontology and Pathway databases. Molecular docking was performed using AutoDockTools 1.5.6 and Discovery Studio 4.5 software. The data demonstrated that there were 16 interlinking target genes of hyperforin with AR, in which BCL6 was the most relevant one with hyperforin in AR. The binding between hyperforin and BCL6 was verified, and molecular docking was modeled. The results revealed that hyperforin inhibited IL-13-induced nasal epithelial inflammatory cytokine release and repressed the damage to the cellular barrier from IL-13 stimulation. In addition, hyperforin activated BCL6 expression and significantly suppressed the expression of p38 MAPK/CCL11. Silencing of BCL6 reversed the effects of hyperforin on IL-13-induced inflammation and barrier damage. In summary, the present results revealed that hyperforin suppressed IL-13-induced nasal epithelial cell inflammation and barrier damage by targeting BCL6/p38 MAPK/CCL11, which may provide promising therapeutic targets for AR.

Protein arginine methyltransferase 1 upregulates matrix metalloproteinase-2/9 expression via Zeste Homolog 2 to promote human rheumatoid arthritis fibroblast-like synovial cell survival and metastasis

OBJECTIVE

To explore the role of protein arginine methyltransferase 1 (PRMT1) in the development of rheumatoid arthritis (RA).

METHODS

Fibroblast-like synoviocytes (FLS) were isolated from synovial tissues, cultured and transfected with plasmid vector or short hairpin RNA (shRNA). The morphology and surface markers of FLS were investigated by light microscopy and flow cytometry. The expression levels of PRMT1, Zeste Homolog 2 (EZH2), matrix metalloproteinase-2 (MMP-2) and MMP-9 were detected by real-time polymerase chain reaction and Western blotting. Cell viability was tested by MTT assay, cell proliferation was assessed by EdU assay, cell invasion was evaluated by Transwell invasion test, cell migration was detected by wound healing assay, and cell apoptosis was detected by flow cytometry.

RESULTS

The expression of PRMT1 was elevated in RA synovial tissues compared with control tissues. FLS from control tissues showed a lower level of PRMT1 than FLS from RA tissues, and FLS from RA tissues had a stronger ability of cell survival and metastasis than those from control tissues. When silencing PRMT1 expression, FLS from RA tissues showed a decreased ability of cell survival and metastasis. Additionally, FLS from RA tissues expressed a higher level of MMP-2 and MMP-9. When silencing PRMT1 expression, the expression of MMP-2 and MMP-9 of FLS was suppressed. Furthermore, the effect of PRMT1 on FLS was mediated by EZH2.

CONCLUSION

We found that PRMT1 had an overall effect on FLS via EZH2, which contributed to the development of RA. Hence, PRMT1 and EZH2 provide potential targets for RA treatment.

Identification of Potential Targets and Mechanisms of Sinomenine in Allergic Rhinitis Treatment Based on Network Pharmacology and Molecular Docking

This study aimed to investigate the potential targets and molecular mechanism of sinomenine in treating allergic rhinitis (AR) using network pharmacology and molecular docking. Relevant targets of sinomenine and AR were obtained from public databases, and differentially expressed genes (DEGs) for AR were identified in the Gene Expression Omnibus database. Using VennDiagram, we identified 22 potential targets of sinomenine against AR by crossing disease targets, drug targets, and DEGs. Functional analysis revealed that sinomenine may act via its anti-inflammatory and immunosuppressive effects, and its action pathways may include the MAPK, HIF-1, and JAK-STAT pathways. Furthermore, hub targets were identified using EPC, MCC, and MNC algorithms, and six hub targets (STAT3, EGFR, NFKB1, HIF1A, PTGS2, and JAK1) were selected by integrating the top 10 hub genes and 22 potential targets. Molecular docking analysis indicated that STAT3, EGFR, PTGS2, and JAK1 may be key targets of sinomenine against AR. Overall, our results suggest that sinomenine has potential therapeutic effects against AR, and its mechanism of action may involve the regulation of key targets and pathways related to inflammation and immunity.

Succinate and mitochondrial DNA trigger atopic march from atopic dermatitis to intestinal inflammation

BACKGROUND

Atopic march has long been recognized as the progression from atopic dermatitis (AD) to food allergy and asthma during infancy and childhood. However, effective blocking is hampered by the lack of specific biomarkers.

OBJECTIVES

We aimed to investigate the pathologic progression of atopic march trajectories from skin to gut.

METHODS

We built an atopic march mouse model by mechanical skin injury and percutaneous sensitization to peanut allergen. Anaphylaxis from the skin to the small intestine was then investigated by ELISA, RNA sequencing, quantitative real-time PCR, histopathologic analysis, and flow cytometry. The findings from the mice results were also verified by the serum samples of allergic pediatric patients.

RESULTS

After modeling, inflammation in the skin and small intestine manifested as a mixed type of T_H2 and T_H17. Further analysis identified elevated succinate in the circulation and expanded tuft cells with upregulated IL-25 in the small intestine, resulting in increased intestinal type 2 innate lymphoid cells and an enhanced type 2 inflammatory response. In addition, free mitochondrial DNA (mtDNA) released after tissue damage was also involved in inflammation march from injured skin to small intestine through the STING pathway. Analysis of clinical samples verified that serum concentrations of succinate and mtDNA were higher in AD allergic children than non-AD allergic children.

CONCLUSIONS

Succinate and mtDNA play key roles in skin-to-gut cross talk during the atopic march from AD to food allergy, and can be considered as biomarkers for risk assessment or targets for atopic march prevention strategies.

Genes related to allergen exposure in allergic rhinitis: a gene-chip-based study in a mouse model

BACKGROUND

The typical clinical symptoms of allergic rhinitis (AR) are known to be associated with allergen exposure; however, the underlying mechanisms are not fully understood. We wanted to gain a comprehensive view of the molecular mechanisms related to allergen exposure in a well-controlled mouse model of AR.

METHODS

An OVA-induced AR model was developed. Two hours and 4 weeks after the last OVA challenge, AR symptoms and local immune responses were assessed. At the same time, differentially expressed genes (DEG) in nasal mucosa were identified by gene expression microarray and further analyzed by bioinformatics methods. Verification of DEG was done by quantitative RT-PCR and immunohistochemistry.

RESULTS

The number of nasal rubbings and sneezes, serum OVA-specific IgE concentrations, and the number of neutrophils and eosinophils in the nasal mucosa were significantly increased at 2 h and decreased at 4 weeks after the last allergen challenge compared to controls. A total of 2119 DEG were identified, and their expression dynamics were clustered into 8 profiles. Enriched functions in Profile 5, which had a similar trend to clinical features, were mainly related to inflammatory and immune response to environmental factors, eosinophils and neutrophils chemotaxis, and cell migration. Gene co-expression Network for genes from profile 5 identified BCL3, NFKB2, SOCS3, and CD53 having a higher degree. Profile 6 showed persistence of inflammatory and immune response at 4 weeks after the last allergen challenge. Olfactory and coagulation functions were enriched mainly in profiles with downward trends.

CONCLUSIONS

A wide range of genes with sequential cooperative action were identified to be associated with allergen exposure in AR. BCL3 may be the most vital in symptoms manifestation. Moreover, some inflammatory responses persisted for a period after allergen exposure, supporting a new treatment strategy of targeting inflammation out of season. This study may contribute to a better understanding of AR pathogenesis and provide potential therapeutic targets for AR patients.

The potential roles of interleukin-25 in infectious diseases

Interleukin-25 (IL-25), also known as IL-17E, is a recently identified cytokine of the IL-17 family. Numerous studies illustrated that the expression of IL-25 is regulated by multiple pathogens, including parasitic, viral, and bacterial infections. IL-25 has a dual function in infectious diseases. On the one hand, IL-25 activates type 2 immunity via the relevant cytokines, including IL-4, IL-5, and IL-13, which are associated with the development of pathogenic infection-related allergic diseases. On the other hand, IL-25 involves in the recruitment of group 2 innate lymphoid cells (ILC2) to enhanced T helper 2 (Th2) cell differentiation, which are important to the clearance of pathogens. However, the precise roles of IL-25 in infectious diseases remain largely unknown. Thus, the current review will shed light on the pivotal roles of IL-25 in infectious diseases.

Cell-Type Specific Expression of Hyaluronan Synthases HAS2 and HAS3 Promotes Goblet Cell Hyperplasia in Allergic Airway Inflammation

Allergic rhinitis (AR) is a multifactorial airway disease characterized by basal and goblet cell hyperplasia. Hyaluronic acid (HA) is a major component of extracellular matrix and a critical contributor to tissue repair and remodeling after injury. We previously demonstrated that the intermediate progenitor cell (IPC) surface marker CD44v3 is upregulated in the basal and suprabasal layers of well-differentiated primary human nasal epithelial (HNE) cells after stimulation with the Th2 cytokine interleukin (IL)-4, and an antibody blocking the CD44v3-HA interaction suppressed IL-4-induced goblet cell hyperplasia. We now show that the expression of HA and two HA synthases, HAS2 and HAS3, was upregulated in both the nasal surface epithelium of subjects with AR and IL-4-stimulated HNE cells. Inhibition of HA synthesis by 4-methylumbelliferone (4-MU) suppressed IL-4-induced goblet cell hyperplasia. Moreover, HAS2 and HAS3 were expressed in IPCs depending on the differentiation events, as follows: the rapid, transient upregulation of HAS2 induced basal IPC proliferation and basal-to-suprabasal transition, whereas the delayed upregulation of HAS3 promoted the transition of suprabasal IPCs to a goblet cell fate. 4-MU treatment in house dust mite-induced murine AR model attenuated goblet cell metaplasia. Lastly, HA levels in nasal epithelial lining fluids from AR patients positively correlated with the levels of mediators causing allergic inflammation. These data suggest that HA produced following the sequential upregulation of HAS2 and HAS3 contributes to goblet cell hyperplasia in allergic airway inflammation and modulates disease progression.

Immune Activation in Functional Dyspepsia: Bystander Becoming the Suspect

Disorders of gut-brain interaction (DGBI), formerly termed functional gastrointestinal disorders (FGID), are highly prevalent although exact pathophysiological mechanisms remain unclear. Intestinal immune activation has been recognized, but increasing evidence supports a pivotal role for an active inflammatory state in these disorders. In functional dyspepsia (FD), marked eosinophil and mast cell infiltration has been repeatedly demonstrated and associations with symptoms emphasize the relevance of an eosinophil-mast cell axis in FD pathophysiology. In this Review, we highlight the importance of immune activation in DGBI with a focus on FD. We summarize eosinophil biology in both homeostasis and inflammatory processes. The evidence for immune activation in FD is outlined with attention to alterations on both cellular and molecular level, and how these may contribute to FD symptomatology. As DGBI are complex and multifactorial conditions, we shed light on factors associated to, and potentially influencing immune activation, including bidirectional gut-brain interaction, allergy and the microbiota. Crucial studies reveal a therapeutic benefit of treatments targeting immune activation, suggesting that specific anti-inflammatory therapies could offer renewed hope for at least a subset of DGBI patients. Lastly, we explore the future directions for DGBI research that could advance the field. Taken together, emerging evidence supports the recognition of FD as an immune-mediated organic-based disorder, challenging the paradigm of a strictly functional nature.

The effects and the mechanisms of naringenin from Artemisia ordosica Krasch on allergic rhinitis based on mast cell degranulation model and network pharmacology

OBJECTIVES

The ethyl acetate extraction of Artemisia ordosica Krasch (AOK) root showed anti-allergic rhinitis (AR) effect, while the active compounds and pharmacological targets were unknown.

METHODS

The P815 degranulation was established by cell counting kit 8 assay, β-hexosaminidase releasing assay and toluidine blue staining. The flavonoids were screened in vitro. Then toluidine blue staining and ELISA were carried out to investigate the anti-inflammatory effects of the active compound. Network pharmacology was implemented to explain the mechanisms of the active compound. iGEMDOCK was used to investigate the binding between active compound and hub targets.

KEY FINDINGS

C48/80 was the optimum reagent in triggering P815 degranulation. Naringenin could significantly decrease P815 degranulation. Meanwhile, naringenin could remarkably increase the IL-4 and decrease the tumour necrosis factor-α. The effect of naringenin on AR was achieved by regulating multiple targets (e.g. AKT1, MAPK3, VEGFA) and pathways (e.g. pathways in cancer, VEGF signalling pathway). Nine hub proteins were obtained by topological analysis. Multiple hydrogen bonds and van der Waals forces were formed between the naringenin and the residues of hub proteins.

CONCLUSIONS

Naringenin might be one of the effective ingredients of AOK against AR. And its effects could achieve through regulating multiple targets and pathways.

TSLP-induced collagen type-I synthesis through STAT3 and PRMT1 is sensitive to calcitriol in human lung fibroblasts

Airway wall remodeling, a main pathology of asthma was linked to vitamin-D deficiency and protein arginine methyltransferase-1 (PRMT1) expression in sub-epithelial cell layers. Calcitriol reduced remodeling in asthma model, but its mode of action is unclear. This study assessed the effect of calcitriol on PRMT1-dependent fibroblast remodeling in human lung fibroblasts, and allergen-induced asthma in E3-rats. Fibroblasts were activated with thymic stromal lymphopoietin (TLSP); asthma was induced by ovalbumin inhalation in rats. The airway structure was assessed by immunohistology. Protein expression in fibroblasts and activation of the mitogen activated protein kinases were detected by Western-blotting. Transcription factor activation was determined by luciferase reporter assay. PRMT1 action was blocked by siRNA and PRMT-inhibition. Ovalbumin upregulated the expression of TSLP, PRMT1, matrix metallopro-teinase-1 (MMP1), interleukin-25, and collagen type-I in sub-epithelial fibroblasts. In isolated fibroblasts, TSLP induced the same proteins, which were blocked by inhibition of Erk1/2 and p38. TLSP induced PRMT1 through activation of signal transducer and activator of transcription-3. PRMT1 inhibition reduced collagen type-I expression and suppressed MMP1. In fibroblasts, calcitriol supplementation over 12 days prevented TSLP-induced remodeling by blocking the PRMT1 levels. Interestingly, short-term calcitriol treatment had no such effect. The data support the beneficial role of calcitriol in asthma therapy.