Interleukin-31 promotes fibrosis and T helper 2 polarization in systemic sclerosis

Regulation of inflammatory cytokines and activation of PI3K/Akt pathway by Yiqi Jiedu Formula in recurrent Herpes Simplex Keratitis: Experimental and network pharmacology evidence

OBJECTIVE

This study investigates the therapeutic effects of the Yiqi Jiedu (YQJD) formula on Herpes Simplex Keratitis (HSK) induced by herpes simplex virus type 1 (HSV-1) and elucidates its mechanisms of action through experimental and network pharmacology approaches.

METHODS

Active ingredients of the YQJD formula were identified using UPLC-HRMS. Network pharmacology was employed to predict shared targets between YQJD and HSK, focusing on the PI3K/Akt signaling pathway. Molecular docking was performed to assess the interaction between key ingredients and targets. In vivo, an HSK mouse model was used to evaluate the YQJD formula's impact on corneal lesions and inflammatory factors. In vitro, human corneal epithelial cells (HCECs) were infected with HSV-1 to assess the formula's effect on IL-4 expression.

RESULTS

UPLC-HRMS identified 34 compounds in YQJD, with Isovitexin and Formononetin exhibiting high oral bioavailability. Network analysis revealed 97 intersecting targets, implicating the PI3K/Akt pathway in YQJD's mechanism. Molecular docking showed strong affinities between IL-4, IL-6, and YQJD compounds. In vivo, YQJD significantly improved corneal lesions and modulated the expression of IL-4, IL-6, and AKT. In vitro, YQJD-containing serum regulated IL-4 expression in HCECs post-HSV-1 infection.

CONCLUSION

The YQJD formula ameliorates Herpes Simplex Keratitis by regulating inflammatory cytokines and activating the PI3K/Akt pathway, offering a potential therapeutic strategy for HSK.

Prevalence and Mechanisms of Itch in Chronic Wounds: A Narrative Review

Itch is a commonly experienced problem by individuals with chronic wounds and greatly compromises their quality of life. Scratching can further hinder the wound healing process. Despite this being a clinically recognized issue, our knowledge of its exact prevalence in chronic wounds of different types and the molecular mechanisms driving it is limited. The multifactorial nature of wound itch makes its characterization particularly challenging. The present review is based on a thorough PubMed search, and it aims to provide an overview of existing evidence on the epidemiology, impact, and pathophysiology of wound itch, along with general recommendations on its management. Importantly, our work highlights the merit of screening chronic wound patients for associated pruritus and incorporating anti-itch measures in mainstream wound care.

A review of recent studies on the pathogenesis of Systemic Sclerosis: focus on fibrosis pathways

Systemic Sclerosis (SSc) is a systemic autoimmune disease of unknown etiology characterized by the development of frequently progressive cutaneous and internal organ fibrosis accompanied by severe vascular alterations. The pathogenesis of SSc is highly complex and, despite extensive investigation, has not been fully elucidated. Numerous studies have suggested that unknown etiologic factors cause multiple alterations in genetically receptive hosts, leading to SSc development and progression. These events may be functionally and pathologically interconnected and include: 1) Structural and functional microvascular and endothelial cell abnormalities; 2) Severe oxidative stress and high reactive oxygen species (3); Frequently progressive cutaneous and visceral fibrosis; 4) Transdifferentiation of various cell types into activated myofibroblasts, the cells ultimately responsible for the fibrotic process; 5) Establishment of a chronic inflammatory process in various affected tissues; 6) Release of cytokines, chemokines, and growth factors from the inflammatory cells; 7) Abnormalities in humoral and cellular immunity with the production of specific autoantibodies; and 8) Epigenetic alterations including changes in multiple non-coding RNAs. These events manifest with different levels of intensity in the affected organs and display remarkable individual variability, resulting in a wide heterogeneity in the extent and severity of clinical manifestations. Here, we will review some of the recent studies related to SSc pathogenesis.

Pathogenesis of systemic sclerosis: an integrative review of recent advances

Systemic sclerosis (SSc), or scleroderma, is a complex autoimmune connective tissue disease characterized by autoimmunity, vasculopathy, and progressive organ fibrosis, leading to severe organ dysfunction. The disease begins with a vascular injury triggered by autoimmune responses and environmental factors against a backdrop of genetic predisposition. This injury impairs angiogenesis and vasculogenesis, resulting in capillary loss and arteriolar constriction, which promotes immune cell infiltration and sustained inflammation within affected tissues. These vascular anomalies cause severe complications, including pulmonary artery hypertension, scleroderma renal crisis, and skin ulcers. Chronic inflammation fosters persistent fibroblast activation, resulting in extensive fibrosis that defines SSc. This review synthesizes the latest research on pathogenesis of SSc, highlighting the shift from fundamental research to a precision therapeutic approach. It explores the potential of technologies like flow cytometry and single-cell RNA sequencing to investigate pathogenic cell subtypes. These platforms integrate transcriptomic, genomic, proteomic, and epigenomic data to uncover insights into the underlying mechanisms of SSc pathogenesis. This review advocates for a multidisciplinary, patient-centric approach that harnesses recent scientific advances, directing future SSc research toward personalized and precise interventions.

A phase 2a trial of brepocitinib for cicatricial alopecia

BACKGROUND

Cicatricial alopecias are chronic, progressive scarring hair-loss conditions. Molecular dysregulation is not fully understood, hindering treatment development. Th1/IFNγ signaling and Janus kinase dysregulation has shown involvement, providing rationale for this phase 2a trial with Tyrosine kinase 2/Janus kinase 1 inhibitor brepocitinib.

METHODS

Randomized, placebo-controlled phase 2a trial spanning 52 weeks. Adults (≥18 years of age) with lichen planopilaris, frontal fibrosing alopecia, or central centrifugal cicatricial alopecia diagnosis were randomized 3:1 to brepocitinib 45 mg daily or placebo for 24 weeks, after which all patients received brepocitinib for another 24 weeks, with a safety follow up 4 weeks later. Lesional scalp biopsies were collected at baseline, week 24, and week 48. Coprimary endpoints were changes in lesional expression of C-C motif chemokine ligand (CCL5), changes in lesional expression of fibrosis-related markers, and safety at week 24.

RESULTS

Patients receiving brepocitinib showed significant downregulation in CCL5 expression at week 24 (P = .004). Enrichment analysis of a subset of fibrosis markers showed trending upregulation in placebo patients (P < .1). Brepocitinib was well tolerated and improved clinical severity scores.

LIMITATIONS

Single-dose regimen, small placebo group.

CONCLUSION

Brepocitinib significantly reduces CCL5 expression and was well tolerated at week 24, meeting coprimary endpoints. Brepocitinib reduces inflammatory biomarker expression and improves clinical severity, while maintaining favorable safety profile.

Topical Application of Nitrate Ameliorates Skin Fibrosis by Regulating ST2+CD4+ T Cells in Systemic Sclerosis Mouse Model

Systemic sclerosis (SSc) is characterized by intractable multiorgan fibrosis caused by vascular and immune dysfunction. Currently, effective therapeutic options for patients with SSc are limited. Nitrate, an abundant nutrient in the diet, has been demonstrated to be preventative and therapeutic for several diseases. To determine whether nitrate can slow or reverse SSc progression, topical application of nitrate delivered by dissolving microneedles was used to treat a bleomycin-induced dermal fibrosis mouse model. In this study, nitrate considerably attenuated dermal thickness, stiffness, and collagen deposition. Bulk RNA sequencing of skin revealed that Cd4 was a key hub gene in SSc nitrate therapy. In addition, bleomycin-induced cytokines and chemokines were inhibited by nitrate, and CD4+ T cells infiltration markedly declined. Il4, Il6, Il13, and Tgfb expressions in CD4+ T cells isolated from skin biopsies also significantly decreased. Mechanistically, Il1rl1, a type 2 immune response inducer, was markedly repressed in isolated CD4+ T cells and dermal tissues after nitrate treatment. Remarkably, compared with wild-type mice, mice lacking Il1rl1 showed impaired transcriptional profiles after intradermal bleomycin injection. Adoptive transfer of ST2+CD4+ T cells promoted bleomycin-induced Rag2-/- mice dermal fibrosis. Collectively, these findings demonstrate that nitrate targeting ST2+CD4+ T cells is an effective therapeutic option for SSc.

Inhibition of CD226 co-stimulation suppresses diabetes development in the NOD mouse by augmenting regulatory T cells and diminishing effector T cell function

AIMS/HYPOTHESIS

Immunotherapeutics targeting T cells are crucial for inhibiting autoimmune disease progression proximal to disease onset in type 1 diabetes. There is an outstanding need to augment the durability and effectiveness of T cell targeting therapies by directly restraining proinflammatory T cell subsets, while simultaneously augmenting regulatory T cell (Treg) activity. Here, we present a novel strategy for preventing diabetes incidence in the NOD mouse model using a blocking monoclonal antibody targeting the type 1 diabetes risk-associated T cell co-stimulatory receptor, CD226.

METHODS

Female NOD mice were treated with anti-CD226 at 7-8 weeks of age and then monitored for diabetes incidence and therapeutic mechanism of action.

RESULTS

Compared with isotype-treated controls, anti-CD226-treated NOD mice showed reduced insulitis severity (0.84-fold, p=0.0002) at 12 weeks and decreased disease incidence (HR 0.41, p=0.015) at 30 weeks. Flow cytometric analysis performed 5 weeks post treatment demonstrated reduced proliferation of conventional CD4+ T cells (0.87-fold, p=0.030) and CD8+ (0.78-fold, p=0.0018) effector memory T cells in spleens of anti-CD226-treated mice. Phenotyping of pancreatic Tregs revealed increased CD25 expression (2.05-fold, p=0.0073) and signal transducer and activator of transcription 5 (STAT5) phosphorylation (1.39-fold, p=0.0007) following anti-CD226, with splenic Tregs displaying augmented suppression of CD4+ responder T cells (Tresps) (1.49-fold, p=0.0008, 1:2 Treg:Tresp) in vitro. Anti-CD226-treated mice exhibited reduced frequencies of islet-specific glucose-6-phosphatase catalytic subunit-related protein (IGRP)-reactive CD8+ T cells in the pancreas, using both ex vivo tetramer staining (0.50-fold, p=0.0317) and single-cell T cell receptor sequencing (0.61-fold, p=0.022) approaches. 51Cr-release assays demonstrated reduced cell-mediated lysis of beta cells (0.61-fold, p<0.0001, 1:1 effector:target) by anti-CD226-treated autoreactive cytotoxic T lymphocytes.

CONCLUSIONS/INTERPRETATION

CD226 blockade reduces T cell cytotoxicity and improves Treg function, representing a targeted and rational approach for restoring immune regulation in type 1 diabetes.

Aberrant Chitinase 3-Like 1 Expression in Basal Cells Contributes to Systemic Sclerosis Fibrosis

Systemic sclerosis (SSc) is an autoimmune disease characterized by extensive skin and internal organ fibrosis. However, the mechanism underlying fibrosis remains unclear, and effective treatments for halting or reversing fibrosis are lacking. In this study, single-cell RNA sequencing is used to obtain a comprehensive overview of skin cells from patients with SSc and healthy controls. A subset of basal cells with high chitinase 3-like 1 (Chi3L1) expression, which potentially plays an important role in fibroblast activation, is identified in SSc. Subsequently, patients with SSc are present with increased expression of Chi3L1 in the skin and serum, and elevated serum levels are associated with skin induration and pulmonary function. Furthermore, Chi3L1 promoted the differentiation of SSc dermal fibroblasts into myofibroblasts, and Chi3L1-deficient (Chi3L1-/-) mice showed amelioration of fibrosis in a bleomycin-induced SSc (BLM-SSc) model. Mechanistically, Chi3L1 mediates fibroblast activation primarily by interacting with interleukin-17 receptor A (IL-17RA), thereby initiating downstream nuclear factor kappa B and mitogen-activated protein kinases signaling pathways. Moreover, the anti-fibrotic effect of IL-17RA antagonists in BLM-SSc mice is demonstrated. In conclusion, Chi3L1 is a potential biomarker for the degree of fibrosis in SSc. Chi3L1 and its receptor, IL-17RA, are promising therapeutic targets for patients with SSc.

Translating tissue expression of STAT 1, 3 and 6 in prurigo nodularis to clinical efficacy of oral tofacitinib - A prospective single-arm investigational study

Background Interleukin (IL)-4, IL-13, IL-17, IL-22 and IL-3 are overexpressed in prurigo nodularis (PN). They mediate their action via the Janus Kinase (JAK) Signal transducer and activator of transcription (STAT) pathway. Objectives Our aim was to study the expression of tissue STAT1, STAT3, and STAT6, as well as the efficacy of the JAK-STAT inhibitor, tofacitinib, in PN. Methods A prospective study was conducted in a tertiary care hospital. Patients with PN were recruited after excluding secondary causes. Pruritus was graded using Pruritus Grading System Score (PGSS). All cases underwent histological assessment using immunohistochemical markers for STAT1, STAT3, and STAT6 in both lesional and perilesional skin. Tofacitinib was initiated at a dose of 5 mg twice daily or 11 mg once daily and then tapered to a maintenance dose. The final PGSS at the time of data evaluation, as well as the occurrence of remissions and relapses, was assessed. Results The majority of the 17 patients included in the study had moderate to severe disease. Immunohistochemical analysis revealed marked tissue expression of STAT6 in 13 and STAT3 in 10 patients, while STAT1 expression was seen in only 4 patients [p < 0.05], suggesting a Th2/Th17 tissue response. The mean onset of action of tofacitinib was 11.2 ± 6.44 days and the mean duration of treatment was 5.6 ± 2.2 months. A significant reduction in PGSS was noted after treatment (66.1%, P value 0.0004). Fourteen of the patients maintained remission on low-dose therapy (5 mg OD or A/D) while one patient experienced a relapse. No serious adverse effects were noted. Limitation We could not study the tissue cytokines and the expression of STATs after achieving clinical response on oral tofacitinib. Conclusion The efficacy of tofacitinib in PN is based on its inhibitory effect on Th2 and Th17 cytokines, which is dependent on STAT6 and STAT3.

Efficient topical treatments of cutaneous lupus erythematosus: a systematic review and network -meta-analysis

Although topical agents have been used to treat cutaneous lupus erythematosus (CLE), there was previously no high-quality evidence of which agents were most effective and which clinical scores were most suitable. On 22 December 2023, a search was conducted across five databases to identify randomized controlled trials (RCTs) for CLE. Two authors independently screened the titles and abstracts of articles based on predetermined criteria. Selected articles were then assessed for inclusion in a blinded manner, with any disagreements resolved through consensus. Data were abstracted in duplicate, and a random-effects model was utilized for network meta-analysis. The certainty of the evidence was evaluated according to the PRISMA guidelines, using the GRADE approach. The analysis was finalized in January 2024, with the primary outcome focused on the change in Cutaneous Lupus Erythematosus Disease Area and Severity Index (CLASI) from baseline. Seven RCTs involving 231 participants were analysed. The network meta-analysis revealed that nicotinamide 4% demonstrated the highest probability of achieving the intended outcomes, with a mean difference (MD) of 3.10 and a 95% confidence interval (CI) of 1.99-4.21. Additionally, clobetasol 0.05%, nicotinamide 2% and tacrolimus 0.1% also exhibited statistically significant differences, with MDs of 2.30 (95% CI of 0.73-3.88), 2.30 (95% CI 0.97-3.63) and 1.30 (95% CI 0.03-2.57), respectively. This NMA demonstrates with a high level of evidence that nicotinamide 4%, clobetasol 0.05%, nicotinamide 2% and tacrolimus 0.1% are statistically significant topical agents for CLE. CLASI may be an appropriate outcome to evaluate drug efficacy in CLE.

Fibrosis mechanisms in systemic sclerosis and new potential therapies

Systemic sclerosis is a rare rheumatic disease characterized by immune cell activation, tissue fibrosis, and endothelial dysfunction. Extracellular matrix synthesis disorder causes widespread fibrosis, primarily in skin and internal organs. Various factors such as TGFβ, VEGF, Galectin-3, and signaling pathways like Wnt/β-catenin are involved in pathophysiological processes. Treatment lacks a unified approach but combines diverse modalities tailored to disease subtype and progression. Current therapeutic strategies include biologics, JAK inhibitors, and IL-6 pathway modulators. Monoclonal antibodies and hypomethylating agents demonstrate potential in fibrosis inhibition. This review focuses on emerging therapeutic evidence regarding drugs targeting collagen, cytokines, and cell surface molecules in systemic sclerosis, aiming to provide insight into potential innovative treatment strategies.

Reassuring humoral and cellular immune responses to SARS-CoV-2 vaccination in participants with systemic sclerosis

Individuals with systemic sclerosis (SSc) are particularly susceptible to SARS-CoV-2 infections, yet it remains to be determined if they generate humoral and cellular responses comparable to controls following SARS-CoV-2 vaccinations. Herein, we collected blood and serum after second, third, and fourth SARS-CoV-2 vaccinations in patients with SSc and controls. Following each dose, participants with SSc mounted comparable serum anti-RBD IgG, anti-RBD IgA, and spike-specific CD4+ and CD8+T cell responses to those found in controls. At 3 months post dose 2, the frequencies of Th1, Th2, Th17, and Treg spike-specific CD4+T cells in participants with SSc did not differ from controls. At 2-6 weeks post dose 3, participants with SSc displayed reduced frequencies, but not numbers, of Th17-polarized spike-specific CD4+T cells. Thus, participants with SSc did not display significantly weaker humoral or cellular responses to SARS-CoV-2 vaccination than controls, enabling reassurance of vaccine immunogenicity in participants with SSc.

Unraveling the Pathogenesis of Calcinosis in Systemic Sclerosis: A Molecular and Clinical Insight

Dystrophic calcinosis, which is the accumulation of insoluble calcified crystalline materials within tissues with normal circulating calcium and phosphorus levels, is a frequent finding in systemic sclerosis (SSc) and represents a major burden for patients. In SSc, calcinosis poses significant challenges in management due to the associated risk of severe complications such as infection, ulceration, pain, reduction in functional capacity and quality of life, and lack of standardized treatment choices. The exact pathogenesis of calcinosis is still unknown. There are multifaceted factors contributing to calcinosis development, including osteogenic differentiation of cells, imbalance between promoter and inhibitors of mineralization, local disturbance in calcium and phosphate levels, and extracellular matrix as a template for mineralization. Several pathophysiological changes observed in SSc such as ischemia, exacerbated production of excessive reactive oxygen species, inflammation, production of inflammatory cytokines, acroosteolysis, and increased extracellular matrix production may promote the development of calcinosis in SSc. Furthermore, mitochondrial dynamics, particularly fission function through the activity of dynamin-related protein-1, may have an effect on the dystrophic calcinosis process. In-depth investigations of cellular mechanisms and microenvironmental influences can offer valuable insights into the complex pathogenesis of calcinosis in SSc, providing potential targeting pathways for calcinosis treatment.

Single cell analysis in systemic sclerosis - A systematic review

In recent years, rapid advances in research methods have made single cell analysis possible. Systemic sclerosis (SSc), a disease characterized by the triad of immune abnormalities, fibrosis, and vasculopathy, has also been the subject of various analyses. To summarize the results of single cell analysis in SSc accumulated to date and to deepen our understanding of SSc. Four databases were used to perform a database search on 23rd June 2023. Assessed Grading of Recommendations Assessment, Development and Evaluation certainty of evidence were performed according to PRISMA guidelines. The analysis was completed on July 2023. 17 studies with 358 SSc patients were included. Three studies used PBMCs, six used skin, nine used lung with SSc-interstitial lung diseases (ILDs), and one used lung with SSc-pulmonary arterial hypertension (PAH). The cells studied included immune cells such as T cells, natural killer cells, monocytes, macrophages, and dendritic cells, as well as endothelial cells, fibroblasts, keratinocytes, alveolar type I cells, basal epithelial cells, smooth muscle cells, mesothelial cells, etc. This systematic review revealed the results of single cell analysis, suggesting that PBMCs, skin, SSc-ILD, and SSc-PAH show activation and dysfunction of cells associated with immune-abnormalities, fibrosis, and vasculopathy, respectively.

Inhibition of CD226 Co-Stimulation Suppresses Diabetes Development in the NOD Mouse by Augmenting Tregs and Diminishing Effector T Cell Function

Aims/hypothesis

Immunotherapeutics targeting T cells are crucial for inhibiting autoimmune disease progression proximal to disease onset in type 1 diabetes. A growing number of T cell-directed therapeutics have demonstrated partial therapeutic efficacy, with anti-CD3 (α-CD3) representing the only regulatory agency-approved drug capable of slowing disease progression through a mechanism involving the induction of partial T cell exhaustion. There is an outstanding need to augment the durability and effectiveness of T cell targeting by directly restraining proinflammatory T helper type 1 (Th1) and type 1 cytotoxic CD8+ T cell (Tc1) subsets, while simultaneously augmenting regulatory T cell (Treg) activity. Here, we present a novel strategy for reducing diabetes incidence in the NOD mouse model using a blocking monoclonal antibody targeting the type 1 diabetes-risk associated T cell co-stimulatory receptor, CD226.

Methods

Female NOD mice were treated with anti-CD226 between 7-8 weeks of age and then monitored for diabetes incidence and therapeutic mechanism of action.

Results

Compared to isotype-treated controls, anti-CD226 treated NOD mice showed reduced insulitis severity at 12 weeks and decreased disease incidence at 30 weeks. Flow cytometric analysis performed five weeks post-treatment demonstrated reduced proliferation of CD4+ and CD8+ effector memory T cells in spleens of anti-CD226 treated mice. Phenotyping of pancreatic Tregs revealed increased CD25 expression and STAT5 phosphorylation following anti-CD226, with splenic Tregs displaying augmented suppression of CD4+ T cell responders in vitro. Anti-CD226 treated mice exhibited reduced frequencies of islet-specific glucose-6-phosphatase catalytic subunit related protein (IGRP)-reactive CD8+ T cells in the pancreas, using both ex vivo tetramer staining and single-cell T cell receptor sequencing (scTCR-seq) approaches. 51Cr-release assays demonstrated reduced cell-mediated lysis of beta-cells by anti-CD226-treated autoreactive cytotoxic T lymphocytes.

Conclusions/interpretation

CD226 blockade reduces T cell cytotoxicity and improves Treg function, representing a targeted and rational approach for restoring immune regulation in type 1 diabetes.

Efficacy and safety of nemolizumab and topical corticosteroids for prurigo nodularis: results from a randomized double-blind placebo-controlled phase II/III clinical study in patients aged ≥ 13 years

BACKGROUND

Prurigo nodularis (PN), a chronic inflammatory skin condition, adversely affects the quality of life of affected individuals. Current treatment options for PN in Japan are limited.

OBJECTIVES

To evaluate the optimal dose, efficacy and safety of long-term treatment with nemolizumab in patients with PN in Japan.

METHODS

In a 16-week double-blind phase II/III study, patients aged ≥ 13 years with PN were randomly assigned (1 : 1 : 1) to nemolizumab 30-mg, 60-mg or placebo groups, with concomitant topical corticosteroids, every 4 weeks. The primary efficacy endpoint was the percentage change in the weekly mean Peak Pruritus Numerical Rating Scale (PP-NRS) score (range 0-10, with higher scores indicating worse itching) from baseline to week 16. Secondary efficacy endpoints assessed the impact of treatment on pruritus, PN severity, sleep and quality of life.

RESULTS

At week 16, the least-squares mean percentage change from baseline in the PP-NRS score was -61.1% in the nemolizumab 30-mg group (n = 77), -56.0% in the 60-mg group (n = 76), and -18.6% in the placebo group (n = 76). Differences between both nemolizumab groups and placebo were significant; the difference between the 30-mg and placebo groups was -42.5% [95% confidence interval (CI) -51.9 to -33.1; P < 0.0001], and between the 60-mg and placebo groups was -37.4% (95% CI -46.7 to -28.1; P < 0.0001). Patients treated with nemolizumab also had greater improvements in the number and severity of prurigo nodules, and in sleep and quality of life compared with the placebo group. Both nemolizumab doses were well tolerated.

CONCLUSIONS

Improvements in PN were greater following nemolizumab treatment, despite continuation of topical corticosteroids in both groups.

The role of B cells in systemic sclerosis

Systemic sclerosis (SSc) is a rare and refractory systemic disease characterized by fibrosis and vasculopathy in the presence of autoimmune abnormalities. While the exact cause of SSc is incompletely understood, the specific autoantibodies identified in SSc are closely linked to disease severity and prognosis, indicating a significant role of autoimmune abnormalities in the pathogenesis of SSc. Although the direct pathogenic mechanisms of autoantibodies in SSc are not fully elucidated, numerous prior investigations have demonstrated the involvement of B cells in the pathogenesis of SSc through various mechanisms. Additionally, several clinical trials have explored the efficacy of B-cell depletion therapy for SSc, with many reporting positive outcomes. However, the role of B cells in SSc pathogenesis is multifaceted, as they can both promote inflammation and exert inhibitory functions. This article provides an overview of the involvement of B cells in SSc development, incorporating the latest research findings.

Cannabinoid receptor 2 selective agonist alleviates systemic sclerosis by inhibiting Th2 differentiation through JAK/SOCS3 signaling

Systemic sclerosis (SSc) poses a significant challenge in autoimmunology, characterized by the development of debilitating fibrosis of skin and internal organs. The pivotal role of dysregulated T cells, notably the skewed polarization toward Th2 cells, has been implicated in the vascular damage and progressive fibrosis observed in SSc. In this study, we explored the underlying mechanisms by which cannabinoid receptor 2 (CB2) highly selective agonist HU-308 restores the imbalance of T cells to alleviate SSc. Using a bleomycin-induced SSc (BLM-SSc) mouse model, we demonstrated that HU-308 effectively attenuates skin and lung fibrosis by specifically activating CB2 on CD4+ T cells to inhibit the polarization of Th2 cells in BLM-SSc mice, which was validated by Cnr2-specific-deficient mice. Different from classical signaling downstream of G protein-coupled receptors (GPCRs), HU-308 facilitates the expression of SOCS3 protein and subsequently impedes the IL2/STAT5 signaling pathway during Th2 differentiation. The deficiency of SOCS3 partially mitigated the impact of HU-308. Analysis of a cohort comprising 80 SSc patients and 82 healthy controls revealed an abnormal elevation in the Th2/Th1 ratio in SSc patients. The proportion of Th2 cells showed a significant positive correlation with mRSS score and positivity of anti-Scl-70. Administration of HU-308 to PBMCs and peripheral CD4+ T cells from SSc patients led to the upregulation of SOCS3, which effectively suppressed the aberrantly activated STAT5 signaling pathway and the proportion of CD4+IL4+ T cells. In conclusion, our findings unveil a novel mechanism by which the CB2 agonist HU-308 ameliorates fibrosis in SSc by targeting and reducing Th2 responses. These insights provide a foundation for future therapeutic approaches in SSc by modulating Th2 responses.

Fibroblast: A Novel Target for Autoimmune and Inflammatory Skin Diseases Therapeutics

Fibroblasts are crucial components of the skin structure. They were traditionally believed to maintain the skin's structure by producing extracellular matrix and other elements. Recent research illuminated that fibroblasts can respond to external stimuli and exhibit diverse functions, such as the secretion of pro-inflammatory factors, adipogenesis, and antigen presentation, exhibiting remarkable heterogeneity and plasticity. This revelation positions fibroblasts as active contributors to the pathogenesis of skin diseases, challenging the traditional perspective that views fibroblasts solely as structural entities. Based on their diverse functions, fibroblasts can be categorized into six subtypes: pro-inflammatory fibroblasts, myofibroblasts, adipogenic fibroblasts, angiogenic fibroblasts, mesenchymal fibroblasts, and antigen-presenting fibroblasts. Cytokines, metabolism, and epigenetics regulate functional abnormalities in fibroblasts. The dynamic changes fibroblasts exhibit in different diseases and disease states warrant a comprehensive discussion. We focus on dermal fibroblasts' aberrant manifestations and pivotal roles in inflammatory and autoimmune skin diseases, including psoriasis, vitiligo, lupus erythematosus, scleroderma, and atopic dermatitis, and propose targeting aberrantly activated fibroblasts as a potential therapeutic strategy for inflammatory and autoimmune skin diseases.

Alterations in peripheral T- and B-cell subsets in patients with systemic sclerosis

OBJECTIVES

To determine the alteration of peripheral T and B cell subsets in patients with systemic sclerosis (SSc) and to evaluate their correlation with the progression of SSc.

METHODS

We recruited 47 SSc patients and 45 healthy controls (HCs) in this study. Demographic and clinical data were then collected. Flow cytometry was used to detect the proportions of 44 different T and B cell subsets in circulating blood.

RESULTS

The proportion of total B cells (p = .043) decreased in SSc patients, together with similar frequencies of total T cells, CD4+ T cells, and CD8+ T cells in both groups. Several subsets of T and B cells differed significantly between these two groups. Follicular helper T cells-1 (Tfh1) (p < .001), helper T cells-1 (Th1) (p = .001), regulatory T cells (Treg) (p = .004), effector memory CD8+ T cells (p = .041), and cytotoxic T cells-17 (Tc17) (p = .01) were decreased in SSc patients. Follicular helper T cells-2 (Tfh2) (p = .001) and, helper T cells-2 (Th2) (p = .001) levels increased in the SSc group. Regulatory B cells (Breg) (p = .015) were lower in the SSc group, together with marginal zone (MZ) B cells (p < .001), memory B cells (p = .001), and non-switched B cells (p = .005). The modified Rodnan skin score (mRSS) correlated with helper T cells-17 (Th17) (r = -.410, p = .004), Tfh1 (r = -.321, p = .028), peripheral helper T cells (Tph) (r = -.364, p = .012) and plasma cells (r = -.312, p = .033).

CONCLUSIONS

The alterations in T and B cells implied immune dysfunction, which may play an essential role in systemic sclerosis.

Novel and potential future therapeutic options in systemic autoimmune diseases

Autoimmune inflammation is caused by the loss of tolerance to specific self-antigens and can result in organ-specific or systemic disorders. Systemic autoimmune diseases affect a significant portion of the population with an increasing rate of incidence, which means that is essential to have effective therapies to control these chronic disorders. Unfortunately, several patients with systemic autoimmune diseases do not respond at all or just partially respond to available conventional synthetic disease-modifying antirheumatic drugs and targeted therapies. However, during the past few years, some new medications have been approved and can be used in real-life clinical settings. Meanwhile, several new candidates appeared and can offer promising novel treatment options in the future. Here, we summarize the newly available medications and the most encouraging drug candidates in the treatment of systemic lupus erythematosus, rheumatoid arthritis, Sjögren's disease, systemic sclerosis, systemic vasculitis, and autoimmune myositis.

Cannabinoids for the treatment of autoimmune and inflammatory skin diseases: A systematic review

In recent years, the medical use of cannabinoids has attracted growing attention worldwide. In particular, anti-inflammatory properties of cannabinoids led to their emergence as potential therapeutic options for autoimmune and inflammatory disorders. Recent studies have also shown that cannabinoid receptors are widely expressed and have endogenous ligands in the skin, suggesting that the skin has its own endocannabinoid system. The aim of this review is to discuss the potential therapeutic effects of cannabinoids in autoimmune and inflammatory skin diseases. Following an overview of cannabinoids and the endocannabinoid system, we describe the cellular and molecular mechanisms of cannabinoids in skin health and disease. We then review the clinical studies of cannabinoids in autoimmune and inflammatory skin diseases including systemic sclerosis (SSc), dermatomyositis (DM), psoriasis (Pso) and atopic dermatitis (AD). A primary literature search was conducted in July 2023, using PubMed and Web of Science. A total of 15 articles were included after excluding reviews, non-human studies and in vitro studies from 389 non-duplicated articles. Available evidence suggests that cannabinoids may be beneficial for SSc, DM, Pso and AD. However, further studies, ideally randomized controlled trials, are needed to further evaluate the use of cannabinoids in autoimmune and inflammatory skin diseases.

[Skin fibrosis : Novel insights in pathophysiology and treatment]

The pathogenesis of fibrosing alterations in the skin and other organ systems is not yet sufficiently understood and current therapeutic options are limited. Fibrosing diseases of the skin lead to a loss of function, which can subsequently be accompanied by serious impairments in quality of life, increased morbidity and ultimately increased mortality. There are currently only a few pharmacological and therapeutic approaches approved to prevent or ameliorate fibrosing diseases. Furthermore, tissue-specific versus common, non-organ-specific pathophysiological cellular and molecular mechanisms are not resolved. The development of new, cause-based and therefore likely more efficient therapeutic approaches is urgently needed. This represents a major challenge, but also opens up the opportunity for special contributions to improve this medically unsolved problem. Here we present important findings from recent years with a focus on the role of the immune response in fibrogenesis.

Serum IL-31 is related to the severity and 3-month prognosis of patients with Intracerebral hemorrhage

Interleukin (IL)-31/IL-33 axis has been proved to play an important role in the regulation of inflammation, and serum IL-33 was found to be a novel serum prognostic marker of intracerebral hemorrhage (ICH), while the value of serum IL-31 levels on prognosis in patients with ICH remains unknown. The present study was designed to study the value of serum IL-31 levels on prognosis in ICH patients. A total of 200 ICH patients and 50 healthy people were included in this study. We collected clinical data such as demographic data, laboratory data, admission disease scores and medical histories of these participants. We measured serum IL-31 levels using enzyme-linked immunosorbent assay, and assessed the prognosis of ICH patients 3 months after onset by mRS scale, and mRS > 2 was defined as a 3-month poor outcome. The level of IL-31 in ICH patients were significantly higher than that in healthy control people (211.91 ± 61.61 vs 167.64 ± 27.45 pg/mL, P < .001), and levels of IL-31 in ICH patients with 3-month good outcome were significantly lower than that in ICH patients with 3-month poor outcome (196.09 ± 50.84 vs 248.05 ± 41.41 pg/mL, P < .001). Results of correlation analysis suggested that the level of serum IL-31 was positively related to admission NIHSS score (r = 0.627, P < .001), hematoma volume (r = 0.352, P < .001), mRS score (r = 0.515, P < .001), high-density lipoprotein-cholesterol (r = 0.177, P = .012), serum C-reactive protein levels (r = 0.483, P < .001), and serum tumor necrosis factor α levels (r = 0.389, P < .001) in ICH patients, while the level of serum IL-31 was negatively related to the admission GCS score (r = -0.518, P < .001) and triglycerides (r = -0.147, P = .038). Results of multivariate regression analysis shows that serum IL-31 levels are an independent risk factor affecting NIHSS scores (OR = 1.023, 95% CI = 1.010-2.036) and 3-month prognosis (OR = 1.023, 95% CI = 0.982-1.747) in ICH patients. The receiver operating characteristic curve analysis showed that the sensitivity and specificity of serum IL-31 level in evaluating the prognosis of ICH were 85.2% and 76.7%, respectively. A cutoff value of serum IL-31 level > 185.30 pg/mL may indicate a poor prognosis for ICH. Serum IL-31 levels on admission in ICH patients are associated with patient prognosis, and higher serum IL-31 levels are associated with a higher risk of poor prognosis in ICH patients.

Optimal treatments and outcome measures of palmoplantar pustulosis: A systematic review and network meta-analysis-based comparison of treatment efficacy

Few studies have made direct comparisons between treatments for palmoplantar pustulosis (PPP); therefore, it is difficult to select the best treatment for each patient. To determine the best therapy and to compare reported measures of efficacy in clinical trials of systemic treatments for PPP in this systematic review and network meta-analysis. Six databases were used to perform database search on 10 July 2022. Randomized controlled trials (RCTs) were identified through a systematic literature search. The titles and abstracts of articles were initially screened for inclusion by two authors independently using our predetermined criteria. The full texts of selected articles were then independently assessed for inclusion in a blinded fashion. Disagreement between the authors was resolved by consensus. Data were abstracted in duplicate. Random-effects model was accepted to perform network meta-analysis. Assessed Grading of Recommendations Assessment, Development and Evaluation certainty of evidence were performed according to the PRISMA guidelines. The analysis was completed in July 2022. The primary outcome was the change of PPP Area and Severity Index (PPPASI) from baseline and the secondary outcome was the achievement of PPPASI-50 response. Seven RCTs with 567 patients were included. Guselkumab 100 mg was the one with the highest probability of reaching the proposed outcomes (mean difference [MD], -8.00; 95% confidence interval [CI], 4.88-11.11), while the achievement of PPPASI-50 response did not show a significant difference (odds ratio [OR], 3.79; 95% CI, 0.51-28.37). Guselkumab 200 mg was next to 100 mg of reaching the proposed outcomes (MD, -4.71; 95% CI, 2.12-7.30), while the achievement of PPPASI-50 response did not show a significant difference (OR, 2.34; 95% CI, 0.48-11.43). Network meta-analysis showed guselkumab 100 mg was the treatment with the highest probability of reaching both PPPASI and PPPASI-50 outcomes. Absolute PPPASI may be more appropriate as an outcome than PPPASI-50.

Immunotherapy Strategy for Systemic Autoimmune Diseases: Betting on CAR-T Cells and Antibodies

Systemic autoimmune diseases (SAIDs), such as systemic lupus erythematosus (SLE), systemic sclerosis (SSc) and rheumatoid arthritis (RA), are fully related to the unregulated innate and adaptive immune systems involved in their pathogenesis. They have similar pathogenic characteristics, including the interferon signature, loss of tolerance to self-nuclear antigens, and enhanced tissue damage like necrosis and fibrosis. Glucocorticoids and immunosuppressants, which have limited specificity and are prone to tolerance, are used as the first-line therapy. A plethora of novel immunotherapies have been developed, including monoclonal and bispecific antibodies, and other biological agents to target cellular and soluble factors involved in disease pathogenesis, such as B cells, co-stimulatory molecules, cytokines or their receptors, and signaling molecules. Many of these have shown encouraging results in clinical trials. CAR-T cell therapy is considered the most promising technique for curing autoimmune diseases, with recent successes in the treatment of SLE and SSc. Here, we overview novel therapeutic approaches based on CAR-T cells and antibodies for targeting systemic autoimmune diseases.

Interleukin 31 receptor α promotes smooth muscle cell contraction and airway hyperresponsiveness in asthma

Asthma is a chronic inflammatory airway disease characterized by airway hyperresponsiveness (AHR), inflammation, and goblet cell hyperplasia. Multiple cytokines, including IFNγ, IL-4, and IL-13 are associated with asthma; however, the mechanisms underlying the effects of these cytokines remain unclear. Here, we report a significant increase in the expression of IL-31RA, but not its cognate ligand IL-31, in mouse models of allergic asthma. In support of this, IFNγ, IL-4, and IL-13 upregulated IL-31RA but not IL-31 in both human and mice primary airway smooth muscle cells (ASMC) isolated from the airways of murine and human lungs. Importantly, the loss of IL-31RA attenuated AHR but had no effect on inflammation and goblet cell hyperplasia in mice challenged with allergens or treated with IL-13 or IFNγ. We show that IL-31RA functions as a positive regulator of muscarinic acetylcholine receptor 3 expression, augmenting calcium levels and myosin light chain phosphorylation in human and murine ASMC. These findings identify a role for IL-31RA in AHR that is distinct from airway inflammation and goblet cell hyperplasia in asthma.

Type 2 cytokines and scleroderma interstitial lung disease

Interstitial lung disease (ILD) is a life-threatening complication of systemic sclerosis (SSc). Type 2 (Th2) cytokines play a pivotal role in airway disease. Study aim was to evaluate serum level of Th2 interleukin (IL) and chemokine in SSc-ILD. Serum levels of IL-4, IL-5, IL-11, IL-13, IL-21, IL-31 and CXCL-13 were measured by Bio-Plex Multiplex Immunoassays in 60 SSc patients and 20 healthy controls (HC). Pulmonary function tests with diffusion lung capacity for carbon monoxide (DLco) and high resolution computed tomography (HRCT) were performed in SSc patients. ILD is defined as fibrotic changes (ground glass, reticular and honeycombing), assessed by Computer-Aided Lung Informatics for Pathology Evaluation and Ratings (CALIPER) software, affecting at least 10% of the lungs. Serum levels of Th2 cytokines were higher in SSc patients than HC. A linear correlation was observed between ground glass and IL-13 (r = 0.342, p < 0.01), IL-21 (r = 0.345, p < 0.01), IL-31 (r = 0.473, p < 0.001), IL-4 (r = 0.863, p < 0.001), IL-5 (r = 0.249, p < 0.05) and peripheral blood eosinophils (r = 0.463, p < 0.001). We found a negative correlation between DLco and IL-4 (r =  - 0.511, p < 0.001) and peripheral blood eosinophils (r =  - 0.446, p < 0.001). In the logistic regression analysis, IL-4 is associated with DLco ≤ 60% of the predicted [OR 1.039 (CI 95%: 1.015-1.064), p < 0.001], whilst mRSS [OR 1.138 (CI 95%: 1.023-1.266), p < 0.05] and IL-4 [OR 1.017 (CI 95%: 1-1.034), p < 0.05] were associated with ILD. Th2 inflammation could play a key role in early phase of SSc-ILD.

Comprehensive autoantibody profiling in systemic autoimmunity by a highly-sensitive multiplex protein array

Comprehensive autoantibody evaluation is essential for the management of autoimmune disorders. However, conventional methods suffer from poor sensitivity, low throughput, or limited availability. Here, using a proteome-wide human cDNA library, we developed a novel multiplex protein assay (autoantibody array assay; A-Cube) covering 65 antigens of 43 autoantibodies that are associated with systemic sclerosis (SSc) and polymyositis/dermatomyositis (PM/DM). The performance of A-Cube was validated against immunoprecipitation and established enzyme-linked immunosorbent assay. Further, through an evaluation of serum samples from 357 SSc and 172 PM/DM patients, A-Cube meticulously illustrated a diverse autoantibody landscape in these diseases. The wide coverage and high sensitivity of A-Cube also allowed the overlap and correlation analysis between multiple autoantibodies. Lastly, reviewing the cases with distinct autoantibody profiles by A-Cube underscored the importance of thorough autoantibody detection. Together, these data highlighted the utility of A-Cube as well as the clinical relevance of autoantibody profiles in SSc and PM/DM.

TRP (transient receptor potential) ion channel family: structures, biological functions and therapeutic interventions for diseases

Transient receptor potential (TRP) channels are sensors for a variety of cellular and environmental signals. Mammals express a total of 28 different TRP channel proteins, which can be divided into seven subfamilies based on amino acid sequence homology: TRPA (Ankyrin), TRPC (Canonical), TRPM (Melastatin), TRPML (Mucolipin), TRPN (NO-mechano-potential, NOMP), TRPP (Polycystin), TRPV (Vanilloid). They are a class of ion channels found in numerous tissues and cell types and are permeable to a wide range of cations such as Ca²⁺, Mg²⁺, Na⁺, K⁺, and others. TRP channels are responsible for various sensory responses including heat, cold, pain, stress, vision and taste and can be activated by a number of stimuli. Their predominantly location on the cell surface, their interaction with numerous physiological signaling pathways, and the unique crystal structure of TRP channels make TRPs attractive drug targets and implicate them in the treatment of a wide range of diseases. Here, we review the history of TRP channel discovery, summarize the structures and functions of the TRP ion channel family, and highlight the current understanding of the role of TRP channels in the pathogenesis of human disease. Most importantly, we describe TRP channel-related drug discovery, therapeutic interventions for diseases and the limitations of targeting TRP channels in potential clinical applications.

Drug development and novel therapeutics to ensure a personalized approach in the treatment of systemic sclerosis

INTRODUCTION

Systemic sclerosis (SSc) is a systemic disease encompassing autoimmunity, vasculopathy, and fibrosis. SSc is still burdened by high mortality and morbidity rates. Recent advances in understanding the pathogenesis of SSc have identified novel potential therapeutic targets. Several clinical trials have been subsequently designed to evaluate the efficacy of a number of new drugs. The aim of this review is to provide clinicians with useful information about these novel molecules.

AREA COVERED

In this narrative review, we summarize the available evidence regarding the most promising targeted therapies currently under investigation for the treatment of SSc. These medications include kinase inhibitors, B-cell depleting agents, and interleukin inhibitors.

EXPERT OPINION

Over the next five years, several new, targeted drugs will be introduced in clinical practice for the treatment of SSc. Such pharmacological agents will expand the existing pharmacopoeia and enable a more personalized and effective approach to patients with SSc. Thus, it will not only possible to target a specific disease domain, but also different stages of the disease.

An up-to-date review of approved and emerging antibody therapies for idiopathic pulmonary fibrosis

INTRODUCTION

The use of pirfenidone and nintedanib in treating Idiopathic Pulmonary Fibrosis (IPF) has shown significant slowing down of the progressive functional decline in these patients. In recent times, antibody-based therapies with precise molecular targets have also been explored as alternative treatments to IPF.

AREAS COVERED

This review aims to summarize the available updates regarding monoclonal antibodies that have been tested in IPF. The drugs describedare developed to antagonize inflammation,immunity pathways and fibrogenesis. Currently, the anti-CTGF pamrevlumab has demonstrated a significant reduction in functional decline as compared to placebo and is undergoing the last stages of phase 3 trial.

EXPERT OPINION

Although antibody-based therapies for IPF have had unsatisfactory results in most trials in the last few years, the pursuit of therapeutic development in this field should continue to deliver a more personalized treatment approach in the future, which is currently not available with existing treatment options. However, several molecules are still under study and some have shown encouraging results in the early phases of clinical trials. Future investigations need to be more carefully designed and valid predictive markers of response to treatment should be used to enhance the effectiveness of future trials.

Functional heterogeneity of human skin-resident memory T cells in health and disease

The human skin is populated by a diverse pool of memory T cells, which can act rapidly in response to pathogens and cancer antigens. Tissue-resident memory T cells (TRM ) have been implicated in range of allergic, autoimmune and inflammatory skin diseases. Clonal expansion of cells with TRM properties is also known to contribute to cutaneous T-cell lymphoma. Here, we review the heterogeneous phenotypes, transcriptional programs, and effector functions of skin TRM . We summarize recent studies on TRM formation, longevity, plasticity, and retrograde migration and contextualize the findings to skin TRM and their role in maintaining skin homeostasis and altered functions in skin disease.

Investigational drugs for the treatment of scleroderma: what's new?

INTRODUCTION

Systemic sclerosis (SSc) is an orphan, chronic, autoimmune, fibrotic disease with unknown etiology characterized by progressive fibrosis of the skin and internal organs. SSc has the highest mortality, the deadliest among the connective tissue diseases, despite the introduction of new treatment options in the past decades.

AREAS COVERED

The aim of the current systematic review was to investigate new targeted therapy and their impact on disease progression, mainly focusing on phase I and II clinical trials within the past three years.

EXPERT OPINION

Despite recent groundbreaking advancements in understanding SSc pathophysiology, early diagnosis and early introduction of effective targeted treatments within the optimal window of opportunity to prevent irreversible disease damage still represents a significant clinical challenge. Ongoing significant research for new molecular and epigenetics pathways is of fundamental importance to offer new perspectives on disease phenotype and for the development of personalized treatment strategies.

Impaired Regulation by IL-35 in Systemic Sclerosis

This study investigated the role of IL-35 in systemic sclerosis (SSc) patients, focusing on CD4+ T cell response and immunomodulatory cytokine production. By comparing the cytokine levels in healthy donors (HD) and SSc patients using ELISAs, we found a significantly lower plasma IL-35 concentration in the SSc patients (52.1 ± 5.6 vs. 143 ± 11.1, p < 0.001). Notably, the IL-35 levels showed a negative correlation with TGF-β (p < 0.001) and IL-17 (p = 0.04). Assessing the IL-35R expression across cell types in the SSc patients and HDs via flow cytometry, we found higher levels on monocytes (40.7 + 5.7 vs. 20.3 ± 1.9, p < 0.001) and lower levels on CD8+ T cells (61.8 ± 9.2 vs. 83.4 ± 0.8, p < 0.05) in the SSc patients. The addition of recombinant IL-35 to stimulated peripheral blood mononuclear cells reduced the IL-17+CD4+ T cell percentage (9.0 ± 1.5 vs. 4.8 ± 0.7, p < 0.05) and increased the IL-35+CD4+ T percentage (4.1 ± 2.3 vs. 10.2 ± 0.8, p < 0.001). In a Treg:Tresponder cell Sco-culture assay with HD and SSc samples, rIL35 decreased the cell proliferation and levels of IL-17A (178.2 ± 30.5 pg/mL vs. 37.4 ± 6.4 pg/mL, p < 0.001) and TGF-β (4194 ± 777 pg/mL vs. 2413 ± 608 pg/mL, p < 0.01). Furthermore, we observed a positive correlation between the modified Rodnan skin score (mRSS) and TGF-β (p < 0.001), while there was a negative correlation between mRSS and IL-35 (p = 0.004). Interestingly, higher levels of plasmatic IL-35 were detected in individuals with limited disease compared to those with diffuse disease (60.1 ± 8.0 vs. 832.3 ± 4.1, p < 0.05). These findings suggest that IL-35 exhibits anti-inflammatory properties in SSc and it may serve as a marker for disease severity and a therapeutic target.

Umbilical-Cord-Derived Mesenchymal Stromal Cells Modulate 26 Out of 41 T Cell Subsets from Systemic Sclerosis Patients

Systemic sclerosis (SSc) is an immune-mediated disease wherein T cells are particularly implicated, presenting a poor prognosis and limited therapeutic options. Thus, mesenchymal-stem/stromal-cell (MSC)-based therapies can be of great benefit to SSc patients given their immunomodulatory, anti-fibrotic, and pro-angiogenic potential, which is associated with low toxicity. In this study, peripheral blood mononuclear cells from healthy individuals (HC, n = 6) and SSc patients (n = 9) were co-cultured with MSCs in order to assess how MSCs affected the activation and polarization of 58 different T cell subsets, including Th1, Th17, and Treg. It was found that MSCs downregulated the activation of 26 out of the 41 T cell subsets identified within CD4+, CD8+, CD4+CD8+, CD4-CD8-, and γδ T cells in SSc patients (HC: 29/42) and affected the polarization of 13 out of 58 T cell subsets in SSc patients (HC: 22/64). Interestingly, SSc patients displayed some T cell subsets with an increased activation status and MSCs were able to downregulate all of them. This study provides a wide-ranging perspective of how MSCs affect T cells, including minor subsets. The ability to inhibit the activation and modulate the polarization of several T cell subsets, including those implicated in SSc's pathogenesis, further supports the potential of MSC-based therapies to regulate T cells in a disease whose onset/development may be due to immune system's malfunction.

Autoantibodies against PIP4K2B and AKT3 Are Associated with Skin and Lung Fibrosis in Patients with Systemic Sclerosis

Systemic sclerosis (SSc) is a rare autoimmune systemic disease that leads to decreased survival and quality of life due to fibrosis, inflammation, and vascular damage in the skin and/or vital organs. Early diagnosis is crucial for clinical benefit in SSc patients. Our study aimed to identify autoantibodies in the plasma of SSc patients that are associated with fibrosis in SSc. Initially, we performed a proteome-wide screening on sample pools from SSc patients by untargeted autoantibody screening on a planar antigen array (including 42,000 antigens representing 18,000 unique proteins). The selection was complemented with proteins reported in the literature in the context of SSc. A targeted antigen bead array was then generated with protein fragments representing the selected proteins and used to screen 55 SSc plasma samples and 52 matched controls. We found eleven autoantibodies with a higher prevalence in SSc patients than in controls, eight of which bound to proteins associated with fibrosis. Combining these autoantibodies in a panel could lead to the subgrouping of SSc patients with fibrosis. Anti-Phosphatidylinositol-5-phosphate 4-kinase type 2 beta (PIP4K2B)- and anti-AKT Serine/Threonine Kinase 3 (AKT3)-antibodies should be further explored to confirm their association with skin and lung fibrosis in SSc patients.

Myocardial Milieu Favors Local Differentiation of Regulatory T Cells

BACKGROUND

In the past years, several studies investigated how distinct immune cell subsets affects post-myocardial infarction repair. However, whether and how the tissue environment controls these local immune responses has remained poorly understood. We sought to investigate how antigen-specific T-helper cells differentiate under myocardial milieu's influence.

METHODS

We used a transgenic T cell receptor (TCR-M) model and major histocompatibility complex-II tetramers, both myosin-specific, combined with single-cell transcriptomics (single-cell RNA sequencing [scRNA-seq]) and functional phenotyping to elucidate how the antigen-specific CD4+ T cells differentiate in the murine infarcted myocardium and influence tissue repair. Additionally, we transferred proinflammatory versus regulatory predifferentiated TCR-M-cells to dissect how they specially contribute to post-myocardial infarction inflammation.

RESULTS

Flow cytometry and scRNA-/TCR-seq analyses revealed that transferred TCR-M cells acquired an induced regulatory phenotype (induced regulatory T cell) in the infarcted myocardium and blunted local inflammation. Myocardial TCR-M cells differentiated into 2 main lineages enriched with either cell activation and profibrotic transcripts (eg, Tgfb1) or suppressor immune checkpoints (eg, Pdcd1), which we also found in human myocardial tissue. These cells produced high levels of LAP (latency-associated peptide) and inhibited IL-17 (interleukin-17) responses. Endogenous myosin-specific T-helper cells, identified using genetically barcoded tetramers, also accumulated in infarcted hearts and exhibited a regulatory phenotype. Notably, TCR-M cells that were predifferentiated toward a regulatory phenotype in vitro maintained stable in vivo FOXP3 (Forkhead box P3) expression and anti-inflammatory activity whereas TH17 partially converted toward a regulatory phenotype in the injured myocardium. Overall, the myosin-specific Tregs dampened post-myocardial infarction inflammation, suppressed neighboring T cells, and were associated with improved cardiac function.

CONCLUSIONS

These findings provide novel evidence that the heart and its draining lymph nodes actively shape local immune responses by promoting the differentiation of antigen-specific Tregs poised with suppressive function.

Interleukin 31 receptor alpha augments muscarinic acetylcholine receptor 3-driven calcium signaling and airway hyperresponsiveness in asthma

Asthma is a chronic inflammatory airway disease characterized by airway hyperresponsiveness (AHR), inflammation, and goblet cell hyperplasia. Both Th1 and Th2 cytokines, including IFN-γ, IL-4, and IL-13 have been shown to induce asthma; however, the underlying mechanisms remain unclear. We observed a significant increase in the expression of IL-31RA, but not its cognate ligand IL-31 during allergic asthma. In support of this, IFN-γ and Th2 cytokines, IL-4 and IL-13, upregulated IL-31RA but not IL-31 in airway smooth muscle cells (ASMC). Importantly, the loss of IL-31RA attenuated AHR but had no effects on inflammation and goblet cell hyperplasia in allergic asthma or mice treated with IL-13 or IFN-γ. Mechanistically, we demonstrate that IL-31RA functions as a positive regulator of muscarinic acetylcholine receptor 3 expression and calcium signaling in ASMC. Together, these results identified a novel role for IL-31RA in AHR distinct from airway inflammation and goblet cell hyperplasia in asthma.

Comprehensive single-cell transcriptional profiling defines shared and unique epithelial injury responses during kidney fibrosis

The underlying cellular events driving kidney fibrogenesis and metabolic dysfunction are incompletely understood. Here, we employed single-cell combinatorial indexing RNA sequencing to analyze 24 mouse kidneys from two fibrosis models. We profiled 309,666 cells in one experiment, representing 50 cell types/states encompassing epithelial, endothelial, immune, and stromal populations. Single-cell analysis identified diverse injury states of the proximal tubule, including two distinct early-phase populations with dysregulated lipid and amino acid metabolism, respectively. Lipid metabolism was defective in the chronic phase but was transiently activated in the very early stages of ischemia-induced injury, where we discovered increased lipid deposition and increased fatty acid β-oxidation. Perilipin 2 was identified as a surface marker of intracellular lipid droplets, and its knockdown in vitro disrupted cell energy state maintenance during lipid accumulation. Surveying epithelial cells across nephron segments identified shared and unique injury responses. Stromal cells exhibited high heterogeneity and contributed to fibrogenesis by epithelial-stromal crosstalk.

SARA suppresses myofibroblast precursor transdifferentiation in fibrogenesis in a mouse model of scleroderma

We previously reported that Smad anchor for receptor activation (SARA) plays a critical role in maintaining epithelial cell phenotype. Here, we show that SARA suppressed myofibroblast precursor transdifferentiation in a mouse model of scleroderma. Mice overexpressing SARA specifically in PDGFR-β+ pericytes and pan-leukocytes (SARATg) developed significantly less skin fibrosis in response to bleomycin injection compared with wild-type littermates (SARAWT). Single-cell RNA-Seq analysis of skin PDGFR-β+ cells implicated pericyte subsets assuming myofibroblast characteristics under fibrotic stimuli, and SARA overexpression blocked the transition. In addition, a cluster that expresses molecules associated with Th2 cells and macrophage activation was enriched in SARAWT mice, but not in SARATg mice, after bleomycin treatment. Th2-specific Il-31 expression was increased in skin of the bleomycin-treated SARAWT mice and patients with scleroderma (or systemic sclerosis, SSc). Receptor-ligand analyses indicated that lymphocytes mediated pericyte transdifferentiation in SARAWT mice, while with SARA overexpression the myofibroblast activity of pericytes was suppressed. Together, these data suggest a potentially novel crosstalk between myofibroblast precursors and immune cells in the pathogenesis of SSc, in which SARA plays a critical role.

Interrelationship and Sequencing of Interleukins4, 13, 31, and 33 - An Integrated Systematic Review: Dermatological and Multidisciplinary Perspectives

The interrelations and sequencing of interleukins are complex (inter)actions where each interleukin can stimulate the secretion of its preceding interleukin. In this paper, we attempt to summarize the currently known roles of IL-4, IL-13, IL-31, and IL-33 from a multi-disciplinary perspective. In order to conduct a comprehensive review of the current literature, a search was conducted using PubMed, Google Scholar, Medscape, UpToDate, and Key Elsevier for keywords. The results were compiled from case reports, case series, letters, and literature review papers, and analyzed by a panel of multi-disciplinary specialist physicians for relevance. Based on 173 results, we compiled the following review of interleukin signaling and its clinical significance across a multitude of medical specialties. Interleukins are at the bed rock of a multitude of pathologies across different organ systems and understanding their role will likely lead to novel treatments and better outcomes for our patients. New interleukins are being described, and the role of this inflammatory cascade is still coming to light. We hope this multi-discipline review on the role interleukins play in current pathology assists in this scope.

The Role of T Cells in Systemic Sclerosis: An Update

Systemic sclerosis (SSc) is a chronic disease characterized by microvasculopathy, autoantibodies (autoAbs), and fibrosis. The pathogenesis of the disease is incompletely understood. Microvasculopathy and autoAbs appear very early in the disease process. AutoAbs, such as those directed against DNA topoisomerase I (Topo I), are disease specific and associated with disease manifestations, and indicate activation of the adaptive immune system. B cells are involved in fibrosis in SSc. T cells are also involved in disease pathogenesis. T cells show signs of antigen-induced activation; T cells of TH2 type are increased and produce profibrotic cytokines interleukin (IL)-4, IL-13, and IL-31; CD4+ cytotoxic T lymphocytes are increased in skin lesions, and cause fibrosis and endothelial cell apoptosis; circulating T follicular helper (TFH) cells are increased in SSc produce IL-21 and promote plasmablast antibody production. On the other hand, regulatory T cells are impaired in SSc. These findings provide strong circumstantial evidence for T cell implication in SSc pathogenesis and encourage new T cell-directed therapeutic strategies for the disease.

T cell abnormalities in systemic sclerosis

Systemic sclerosis (SSc) is an autoimmune disease with a poor prognosis. To date, the pathogenesis of SSc is still unclear; moreover, its pathological conditions include microvascular damage, inflammation, and immune abnormalities. Different types of T cells may cause vasculitis and fibrosis in SSc by means of up- and down-regulation of cell surface molecules, abnormal release of pro-fibrotic or pro-inflammatory cytokines and direct contact with fibroblasts. These T cells, which are mainly CD4 + T cells, include the subtypes, T follicular helper (Tfh) cells, regulatory T Cells (Treg), interleukin-17 (IL-17)-producing Th17 cells, CD4⁺ cytotoxic T lymphocytes (CTLs), and angiogenic T (Tang) cells. In addition to the Th1/Th2 imbalance, which has long been established, there is also a Th17/Treg imbalance in SSc. This imbalance may be closely related to the abnormal immune status of SSc. There is mounting evidence that suggest T cell abnormalities may be crucial to the pathogenesis of SSc. In terms of treatment, existing therapies that target T cells, such as immunosuppressive therapy (tacrolimus), Janus kinase(JAK) inhibitors, and biologics(abatacept), have had some success. Other non-drug therapies, including Mesenchymal stem cells (MSCs), have extensive and complex mechanisms of action actually including T cell regulation. Based on the current evidence, we believe that the study of T cells will further our understanding of the pathogenesis of SSc, and may lead to more targeted treatment optionsfor patients with SSc.

Involvement of B cells in the development of systemic sclerosis

Systemic sclerosis (SSc) is a rare intractable systemic disease that causes fibrosis and vasculopathy against a background of autoimmune abnormalities. Although the etiology is not yet fully understood, the type of autoantibodies detected in SSc is closely associated with disease severity and prognosis, supporting that those autoimmune abnormalities play an important role in the pathogenesis of SSc. Although the direct pathogenicity of autoantibodies found in SSc is unknown, many previous studies have shown that B cells are involved in the development of SSc through a variety of functions. Furthermore, a number of clinical studies have been conducted in which B-cell depletion therapy has been tried for SSc, and many of these studies have found B-cell depletion therapy to be effective for SSc. However, the involvement of B cells in pathogenesis is complex, as they not only promote inflammation but also play an inhibitory role. This article outlines the role of B cells in the development of SSc, including the latest research.

Involvement of Molecular Mechanisms between T/B Cells and IL-23: From Palmoplantar Pustulosis to Autoimmune Diseases

Palmoplantar pustulosis (PPP) is a disease that causes recurrent blisters and aseptic pustules on the palms and soles. It has been suggested that both innate and acquired immunity are involved. In particular, based on the tonsils and basic experiments, it has been assumed that T and B cells are involved in its pathogenesis. In addition, the results of clinical trials have suggested that IL-23 is closely related to the pathogenesis. This review describes PPP and the genetic background, the factors involved in the onset and exacerbation of disease and its relation to the molecular mechanism. In addition, we describe the usefulness of biological therapy and its implications in relation to the importance in pathology, the pathogenesis of PPP, the importance of the role of the IL-23-Th17 axis and IL-36 in PPP. Furthermore, we describe an animal experimental model of PPP, the efficacy and mechanism of action of guselkumab, an anti-IL-23 antibody, the latest research, and finally the possibility for it to be effective for other autoimmune diseases.

Nemolizumab: First Approval

Nemolizumab is a subcutaneously administered humanized anti-interleukin-31 (IL-31) receptor A (IL-31RA) monoclonal antibody that is being developed by Chugai Pharmaceutical Co. Ltd, Maruho Co. Ltd and Galderma Pharma S.A. for the treatment of skin diseases, including atopic dermatitis (AD), AD associated pruritus (ADaP), prurigo nodularis (PN), chronic kidney disease associated pruritus (CKDaP) and systemic sclerosis (SSc). IL-31 is a neuroimmune cytokine that induces itch, inflammation, keratinocyte differentiation and fibroblast activation in chronic pruritic skin diseases. Nemolizumab (Mitchga^® Syringes) was approved in Japan on 28 March 2022 for use in adults and children over the age of 13 years for the treatment of itch associated with AD (only when existing treatment is insufficiently effective). This article summarizes the milestones in the development of nemolizumab leading to this first approval.