The role and mechanism of cathepsin G in dermatomyositis

Update on protease-activated receptor 2 in inflammatory and autoimmune dermatological diseases

Protease-activated receptor 2 (PAR2) is a cell-surface receptor expressed in various cell types, including keratinocytes, neurons, immune and inflammatory cells. Activation of PAR2, whether via its canonical or biased pathways, triggers a series of signaling cascades that mediate numerous functions. This review aims to highlight the emerging roles and interactions of PAR2 in different skin cells. It specifically summarizes the latest insights into the roles of PAR2 in skin conditions such as atopic dermatitis (AD), psoriasis, vitiligo and melasma. It also considers these roles from the perspective of the cutaneous microenvironment in relation to other inflammatory and autoimmune dermatological disorders. Additionally, the review explores PAR2's involvement in associated comorbidities from both cutaneous and extracutaneous diseases. Therefore, PAR2 may serve as a key target for interactions among various cells within the local skin environment.

CTSG may inhibit disease progression in HIV-related lung cancer patients by affecting immunosuppression

OBJECTIVES

Lung cancer is an independent risk factor for pulmonary complications following HIV infection. This study aimed to examine the expression and clinical significance of Cathepsin G (CTSG) protein in both non-HIV and HIV-related lung cancers.

METHODS

The data related to lung adenocarcinoma (LUAD) and lung squamous carcinoma (LUSC) in the TCGA dataset and the data related to healthy individuals in the GTEx dataset, the GEPIA2 database was used to excavate the distinction in the expression of CTSG protein in non-small cell lung cancer (NSCLC) tissues versus normal non-cancerous tissues. The Ualcan database was used to compare the differences in CTSG expression at different stages of LUAD and LUSC. Immunohistochemistry (IHC) was used to detect the expression of CTSG proteins in the pathological tissues of patients with HIV-related lung cancer and patients with lung cancer without co-infection, the Kaplan-Meier method was used for survival analysis.

RESULTS

We observed that CTSG expression in NSCLC is lower compared to adjacent non-tumor tissues and correlates with NSCLC clinical stage. CTSG protein expression in HIV-related lung cancer tissues was lower than in adjacent tissues and lower than in lung cancer tissues without HIV infection, with a statistically significant difference (P < 0.05). It correlated with CD4 + T cell count and CD4+/CD8 + T cell ratio, as well as with the pathological type, distant metastasis, and clinical stage of HIV-related lung cancer, all with statistical significance (P < 0.05).

CONCLUSIONS

CTSG could potentially mitigate disease advancement in HIV-related lung cancer patients by inhibiting immune depletion, serving as a prospective immunotherapeutic target for both non-HIV and HIV-associated lung cancers.

Epigenetic mechanisms driving the pathogenesis of systemic lupus erythematosus, systemic sclerosis and dermatomyositis

Autoimmune connective tissue disorders, including systemic lupus erythematosus, systemic sclerosis (SSc) and dermatomyositis (DM), often manifest with debilitating cutaneous lesions and can result in systemic organ damage that may be life-threatening. Despite recent therapeutic advancements, many patients still experience low rates of sustained remission and significant treatment toxicity. While genetic predisposition plays a role in these connective tissue disorders, the relatively low concordance rates among monozygotic twins (ranging from approximately 4% for SSc to about 11%-50% for SLE) have prompted increased scrutiny of the epigenetic factors contributing to these diseases. In this review, we explore some seminal studies and key findings to provide a comprehensive understanding of how dysregulated epigenetic mechanisms can contribute to the development of SLE, SSc and DM.

The role and mechanism of myeloperoxidase in dermatomyositis

OBJECTIVE

Dermatomyositis (DM) is the best known subtype of idiopathic inflammatory myopathies. The hallmarks of DM muscle pathology including microangiopathy, inflammatory infiltration, and perifascicular atrophy. Recent findings have revealed pathogenetic effects of myeloperoxidase (MPO) by causing oxidative damage and regulating abnormal immunity in multiple disease conditions. In this study, we aimed to explore the role of MPO in the pathogenesis of DM.

METHODS

The peripheral blood mononuclear cell (PBMC) mRNA expression and DNA methylation of MPO were verified using real-time qPCR and bisulfite pyrosequencing, respectively. Plasma MPO levels were measured with enzyme-linked immunosorbent assay, and their relationships with clinical characteristics were analyzed. The expression and distribution of MPO in muscle were tested by immunofluorescence. Purified human native MPO protein was used to stimulate human dermal microvascular endothelial cells (HDMECs) and skeletal muscle myotubes. The cell viability, tube forming capacity, permeability, adhesion molecule expressions in HDMECs, and atrophy and programmed cell death pathways in myotubes were then observed.

RESULTS

MPO gene methylation was decreased, while mRNA expression and plasma levels were increased in DM. Plasma MPO of DM patients was positively correlated with serum creatine kinase (CK). MPO mainly distributed around endomysia capillaries and perifascicular atrophy in DM muscle biopsies, and was co-localized with CD4+, CD8+ T cells and CD19+ B cells. MPO not only could influence the cell viability, tube forming capacity, permeability and expression of adhesion molecules (including ICAM 1, VCAM 1 and E-selectin) of HDMECs, but also could cause atrophy of myotubes.

CONCLUSIONS

Our study disclosed, for the first time, that MPO plays an important role in promoting inflammatory infiltration and inducing muscle damage in DM patients. MPO may be a potential biomarker for DM muscle involvement and MPO targeted drugs may be promising in DM treatment.

Single-cell analysis reveals melanocytes may promote inflammation in chronic wounds through cathepsin G

During acute wound (AW) healing, a series of proper communications will occur between different epidermal cells at precise temporal stages to restore the integrity of the skin. However, it is still unclear what variation happened in epidermal cell interaction in the chronic wound environment. To provide new insights into chronic wound healing, we reconstructed the variations in the epidermal cell-cell communication network that occur in chronic wound healing via single-cell RNA-seq (scRNA-seq) data analysis. We found that the intricate cellular and molecular interactions increased in pressure ulcer (PU) compared to AW, especially the PARs signaling pathways were significantly upregulated. It shows that the PARs signaling pathways' main source was melanocytes and the CTSG-F2RL1 ligand-receptor pairs were its main contributor. Cathepsin G (CatG or CTSG) is a serine protease mainly with trypsin- and chymotrypsin-like specificity. It is synthesized and secreted by some immune or non-immune cells. Whereas, it has not been reported that melanocytes can synthesize and secrete the CTSG. F2R Like Trypsin Receptor 1 (F2RL1) is a member of proteinase-activated receptors (PARs) that are irreversibly activated by proteolytic cleavage and its stimulation can promote inflammation and inflammatory cell infiltration. In this study, we found that melanocytes increased in pressure ulcers, melanocytes can synthesize and secrete the CTSG and may promote inflammation in chronic wounds through CTSG-F2RL1 pairs, which may be a novel potential target and a therapeutic strategy in the treatment of chronic wounds.

Novel role of long non-coding RNAs in autoimmune cutaneous disease

Systemic autoimmune rheumatic diseases (SARDs) are a heterogeneous group of chronic multisystem inflammatory disorders that are thought to have a complex pathophysiology, which is not yet fully understood. Recently, the role of non-coding RNAs, including long non-coding RNA (lncRNA), has been of particular interest in the pathogenesis of SARDs. We aimed to summarize the potential roles of lncRNA in SARDs affecting the skin including, systemic sclerosis (SSc), dermatomyositis (DM) and cutaneous lupus erythematosus (CLE). We conducted a narrative review summarizing original articles published until July 19, 2021, regarding lncRNA associated with SSc, DM, and CLE. Several lncRNAs were hypothesized to play an important role in disease pathogenesis of SSc, DM and CLE. In SSc, Negative Regulator of IFN Response (NRIR) was thought to modulate Interferon (IFN) response in monocytes, anti-sense gene to X-inactivation specific transcript (TSIX) to regulate increased collagen stability, HOX transcript antisense RNA (HOTAIR) to increase numbers of myofibroblasts, OTUD6B-Anti-Sense RNA 1 to decrease fibroblast apoptosis, ncRNA00201 to regulate pathways in SSc pathogenesis and carcinogenesis, H19X potentiating TGF-β-driven extracellular matrix production, and finally PSMB8-AS1 potentiates IFN response. In DM, linc-DGCR6-1 expression was hypothesized to target the USP18 protein, a type 1 IFN-inducible protein that is considered a key regulator of IFN signaling. Additionally, AL136018.1 is suggested to regulate the expression Cathepsin G, which increases the permeability of vascular endothelial cells and the chemotaxis of inflammatory cells in peripheral blood and muscle tissue in DM. Lastly, lnc-MIPOL1-6 and lnc-DDX47-3 in discoid CLE were thought to be associated with the expression of chemokines, which are significant in Th1 mediated disease. In this review, we summarize the key lncRNAs that may drive pathogenesis of these connective tissue diseases and could potentially serve as therapeutic targets in the future.

Exploring the Mechanism of Aspirin in the Treatment of Kawasaki Disease Based on Molecular Docking and Molecular Dynamics

Purpose

The research aims to investigate the mechanism of action of aspirin in the treatment of Kawasaki disease.

Methods

We predicted the targets of aspirin with the help of the Drugbank and PharmMapper databases, the target genes of Kawasaki disease were mined in the GeneCards and Disgenet databases, the intersection targets were processed in the Venny database, and the gene expression differences were observed in the GEO database. The Drugbank and PharmMapper databases were used to predict the target of aspirin, and the target genes of Kawasaki disease were explored in the GeneCards and Disgenet databases, and the Venny was used for intersection processing. We observed the gene expression differences in the GEO database. The disease-core gene target-drug network was established and molecular docking was used for verification. Molecular dynamics simulation verification was carried out to combine the active ingredient and the target with a stable combination. The supercomputer platform was used to measure and analyze the binding free energy, the number of hydrogen bonds, the stability of the protein target at the residue level, the radius of gyration, and the solvent accessible surface area.

Results

Aspirin had 294 gene targets, Kawasaki disease had 416 gene targets, 42 intersecting targets were obtained, we screened 13 core targets by PPI; In the GO analysis, we learned that the biological process of Kawasaki disease involved the positive regulation of chemokine biosynthesis and inflammatory response; pathway enrichment involved PI3K-AKT signaling pathway, tumor necrosis factor signaling pathway, etc. After molecular docking, the data showed that CTSG, ELANE, and FGF1 had the best binding degree to aspirin. Molecular dynamics was used to prove and analyze the binding stability of active ingredients and protein targets, and Aspirin/ELANE combination has the strongest binding energy.

Conclusion

In the treatment of Kawasaki disease, aspirin may regulate inflammatory response and vascular remodeling through CTSG, ELANE, and FGF1.

The Role of Immune Cells in the Pathogenesis of Idiopathic Inflammatory Myopathies

Idiopathic inflammatory myopathies (IIMs) are chronic autoimmune disorders involving multiple organs, such as the muscle, skin, lungs and joints. Although the detailed pathogenesis of IIMs remains unclear, immune mechanisms have long been recognised as of key importance. Immune cells contribute to many inflammatory processes via intercellular interactions and secretion of inflammatory factors, and many studies have demonstrated the participation of a variety of immune cells, such as T cells and B cells, in the development of IIMs. Here, we summarise the current knowledge regarding immune cells in IIM patients and discuss their potential roles in IIM pathogenesis.

Role of DNA methylation on human CTSG in dermatomyositic myoideum

Dermatomyositis (DM) is a multifactorial chronic autoimmune disorder with characteristic skin and muscle pathological changes and involvement of other organ systems. Cathepsin G (CTSG) contributes to the risk of developing DM, which is likely to be associated with inflammatory cytokines. Differential DNA methylation on CTSG has been determined to be implicated in DM in vivo. However, the underlying mechanism of this epigenetic regulation on CTST in DM is poorly explored. In this study, we investigated DNA methylation signature on CTSG at single-nucleotide resolution in quadriceps femoris of six DM patients and paracancerous muscles of three patients with rhabdomyosarcoma on inner thigh using pyrosequencing and observed that the overall DNA methylation level of CTSG was increased in DM compared with control, in which CpG loci at third and fourth exons but not promoter contributed to the significant hypermethylation. Furthermore, we observed that transcription and DNA methylation of CTSG were both declined in DNMT3a knockdown compared with DNMT1 and DNMT3b knockdown in human skeletal muscle SJCRH30 and A-204 cell lines exposed to tumor necrosis factor-α. Furthermore, Bortezomib (NF-κB inhibitor) and Brevilin A (JAK/STAT inhibitor) were employed to treat SJCRH30 and A-204 cells, respectively, and we observed that CTSG was hypomethylated and silenced after Bortezomib treatment compared with untreatment and Brevilin A. Finally, chromatin immunoprecipitation-quantitative polymerase chain reaction indicated that DNMT3a could bind to the coding regions of CTSG and the interaction was dependent on NF-κB activity. Taken together, our results determined a novel regulatory mechanism of DNA methylation on CTSG in DM.

Ammonia-triggered apoptosis via immune function and metabolic process in the thymuses of chickens by proteomics analysis

Ammonia (NH₃), an environmental pollutant with a pungent odor, is not only an important volatile in fertilizer production and ranching, but also main basic component of haze. In present study, we found that ultrastructural changes and 3167 differentially expressed proteins (DEPs) using proteomics analysis in the thymuses of chickens exposed to NH₃ on day 42. Obtained DEPs were enriched using GO and KEGG; and 66 DEPs took part in immune function, metabolic process, and apoptosis in the thymuses of chickens treated with NH₃. 9 genes of DEPs were validated using qRT-PCR, and mRNA expression of 2 immune-related genes (CTSG and NFATC2), 3 metabolic process-related genes (APOA1, GOT1, and GOLGA3), and 4 apoptosis-related genes (PIK3CD, CTSS, CAMP, and NSD2) were consistent with DEPs in chicken thymuses. Our results indicated that excess NH₃ led to immunosuppression, metabolic disorder, and apoptosis in chicken thymuses. Present study gives a novel insight into the mechanism of NH₃ toxicity and demonstrated that immune response, metabolism process, and apoptosis were important in the mechanism of NH₃ toxicity of chicken exposure to high concentration of NH₃.

Correlation of PMN elastase and PMN elastase-to-neutrophil ratio with disease activity in patients with myositis

Background

Polymorphonuclear (PMN) elastase plays an important role in a variety of inflammatory disorders. Our aim was to analyse PMN elastase in idiopathic inflammatory myopathies (IIMs) and its association with disease activity.

Methods

PMN elastase levels were measured using enzyme-linked immunosorbent assay in serum samples obtained from 74 patients with myositis (58 with dermatomyositis [DM] and 16 with polymyositis [PM]) and 22 healthy controls. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the discriminant capacity of PMN elastase level and PMN elastase-to-neutrophil ratio (ENR) in patients with active and remission myositis. The association of serum PMN elastase level and ENR with disease variables was evaluated in patients with IIMs. The disease specificity of PMN elastase level and ENR was further examined in 60 patients with other systemic autoimmune diseases.

Results

PMN elastase level and ENR were significantly higher in patients with active IIMs, DM, and PM than in patients with remission. ROC curve analysis revealed that PMN elastase level and ENR both outperformed creatine kinase (CK), the currently used laboratory marker, and strongly discriminated patients with active disease and those with remission of IIMs, DM, and PM (area under the ROC curve [AUC] 0.9, 0.9, and 0.88 for PMN elastase; AUC 0.96, 0.96, and 1.0 for ENR; AUC 0.72, 0.70, and 0.80 for CK, respectively). PMN elastase level and ENR were positively correlated with myositis disease activity assessment, CK, lactate dehydrogenase, aspartate aminotransferase, alanine aminotransferase, C-reactive protein, and erythrocyte sedimentation rate. PMN elastase level and ENR were higher in the anti-PM-Scl positive myositis group than those in the anti-PM-Scl negative myositis group. Nevertheless, PMN elastase was not a specific disease marker for IIMs when compared with other autoimmune diseases.

Conclusions

PMN elastase, particularly ENR, were significantly correlated with disease activity and could serve as useful biochemical markers for evaluating the disease activity of patients with IIMs. Thus, they are potentially helpful in monitoring disease progression and guiding treatment.

Association of autoimmunity and cancer: An emphasis on proteolytic enzymes

Cancer and autoimmune diseases are the two devastating conditions that together constitute a leading health problem worldwide. The rising burden of these disorders in the developing world demands a multifaceted approach to address the challenges it poses. Understanding the root causes and specific molecular mechanisms by which the progression of the diseases takes place is need of the hour. A strong inflammatory background and common developmental pathways, such as activation of immune cells, proliferation, increased cell survival and migration which are controlled by growth factors and inflammatory cytokines have been considered as the critical culprits in the progression and complications of these disorders. Enzymes are the potential immune modulators which regulate various inflammatory events and can break the circulating immune complexes via macrophages production. In the current manuscript, we have uncovered the possible role of proteolytic enzymes in the pathogenesis and progression of cancer and autoimmune diseases. In the light of the available scientific literature, we advocate in-depth comprehensive studies which will shed light towards the role of proteolytic enzymes in the modulation of inflammatory responses in cancer and autoimmune diseases together.

Global analysis of protein expression in muscle tissues of dermatomyositis/polymyosisits patients demonstrated an association between dysferlin and human leucocyte antigen A

OBJECTIVES

DM and PM are characterized by myofibre damage with inflammatory cell infiltration due to the strong expressions of MHC class I HLA-A and monocyte chemoattractant protein-1 (MCP-1). Dysferlin (DYSF) is a transmembrane glycoprotein that anchors in the sarcolemma of myofibres. DYSF mutation is closely associated with inherited myopathies. This study aimed to determine the role of DYSF in the development of DM/PM.

METHODS

Mass spectrometry was performed in muscle tissues from DM/PM patients and controls. The DYSF levels in muscle tissue, peripheral blood cells and serum were detected by Western blotting, IF, flow cytometry or ELISA. Double IF and co-immunoprecipitation were used to investigate the relationship between DYSF and HLA-A.

RESULTS

Mass spectrometry and bioinformatics analysis findings suggested the dysregulated proteins in DM/PM patients participated in common biological processes and pathways, such as the generation of precursor metabolites and energy. DYSF was upregulated in the muscle tissue and serum of DM/PM patients. DYSF was mainly expressed in myofibres and co-localized with HLA-A and MCP-1. DYSF and HLA-A expressions were elevated in myocytes and endothelial cells after being stimulated by patient serum and IFN-β. However, no direct interactions were found between DYSF and HLA-A by co-immunoprecipitation.

CONCLUSION

Our study revealed the dysregulated proteins involved in common and specific biological processes in DM/PM patient samples. DYSF is upregulated and exhibits a potential role along with that of HLA-A and MCP-1 in inflammatory cell infiltration and muscle damage during the development of DM/PM.

Integrated comparison of the miRNAome and mRNAome in muscles of dermatomyositis and polymyositis reveals common and specific miRNA–mRNAs

Aim: Dermatomyositis (DM) and polymyositis (PM) are refractory systemic autoimmune diseases with unknown pathogenesis. miRNAs is an important epigenetic mechanism to regulate gene expression. Methods: We performed whole miRNAs analysis, transcription analysis and the association between miRNAome and mRNAome. Results: For transcription and miRNAs analysis, there were common and specific mRNAs and miRNAs in the muscles of DM and PM. Among them, the expression levels of miR-196a-5p and CPM were negatively correlated in PM, miR-193b-3p and NECAP2 were negatively correlated in DM and PM. Protein carboxypeptidase M (CPM) plays roles in the degradation of extracellular proteins and in the migration and invasion of cancer cells, and protein NECAP2 plays roles in adaptor protein AP-1-mediated fast recycling from early endosomes. The functions of them in the pathogenesis of DM/PM need further studies. Conclusion: Our study identified and confirmed differentially miRNAs and mRNAs in DM and PM. Our observations have laid the groundwork for further diagnostic and mechanistic studies of DM and PM.

The roles of neutrophil serine proteinases in idiopathic inflammatory myopathies

Background

Dermatomyositis and polymyositis are the best known idiopathic inflammatory myopathies (IIMs). Classic histopathologic findings include the infiltration of inflammatory cells into muscle tissues. Neutrophil serine proteinases (NSPs) are granule-associated enzymes and play roles in inflammatory cell migration by increasing the permeability of vascular endothelial cells. In this study, we aimed to find the roles of NSPs in pathogenesis of IIMs.

Methods

RNA and DNA were isolated to measure the relative expression of NSPs and their methylation levels. The expression of NSPs in serum and muscle tissues was tested by enzyme-linked immunosorbent assay, immunohistochemistry, and immunofluorescence, respectively. Serum from patients was used to culture the human dermal microvascular endothelial cells (HDMECs), and then we observed the influence of serum on expression of VE-cadherin, endothelial cell tube formation, and transendothelial migration of peripheral blood mononuclear cells (PBMCs).

Results

We found that the expression of NSPs was increased in PBMCs, serum, and muscle tissues of IIM patients; these NSPs were hypomethylated in the PBMCs of patients. Serum NSPs were positively correlated with clinical indicators of IIM patients, including lactic dehydrogenase, erythrocyte sedimentation rate, C-reactive protein, immunoglobulin G, immunoglobulin M, and immunoglobulin A. Patients with anti-Jo-1, with anti-Ro-52, or without interstitial lung disease had lower levels of proteinase 3. Serum NSPs degraded the VE-cadherin of HDMECs, and serum NSP application increased the permeability of HDMECs.

Conclusions

Our studies indicate, for the first time, that NSPs play an important role in muscle inflammatory cell infiltration by increasing the permeability of vascular endothelial cells in IIM patients.

Electronic supplementary material

The online version of this article (10.1186/s13075-018-1632-x) contains supplementary material, which is available to authorized users.

Cathepsin G and Its Role in Inflammation and Autoimmune Diseases

Cathepsin G belongs to the neutrophil serine proteases family, known for its function in killing pathogens. Studies over the past several years indicate that cathepsin G has important effects on inflammation and immune reaction, and may be a key factor in the pathogenesis of some autoimmune diseases. In this article, we discuss the roles of cathepsin G in inflammation, immune reaction, and autoimmune diseases. To our knowledge, this is the first study providing important information about cathepsin G in the pathogenesis of autoimmune diseases and suggesting that cathepsin G may be a new biomarker or treatment target.