Differentiation of IL-26+ TH17 intermediates into IL-17A producers via epithelial crosstalk in psoriasis

Emerging Techniques in Spatial Multiomics: Fundamental Principles and Applications to Dermatology

Molecular pathology, such as high-throughput genomic and proteomic profiling, identifies precise disease targets from biopsies but require tissue dissociation, losing valuable histologic and spatial context. Emerging spatial multi-omic technologies now enable multiplexed visualization of genomic, proteomic, and epigenomic targets within a single tissue slice, eliminating the need for labeling multiple adjacent slices. Although early work focused on RNA (spatial transcriptomics), spatial technologies can now concurrently capture DNA, genome accessibility, histone modifications, and proteins with spatially-resolved single-cell resolution. This review outlines the principles, advantages, limitations, and potential for spatial technologies to advance dermatologic research. By jointly profiling multiple molecular channels, spatial multiomics enables novel studies of copy number variations, clonal heterogeneity, and enhancer dysregulation, replete with spatial context, illuminating the skin's complex heterogeneity.

Psoriasis: A Multidimensional Review of Onset, Progression, Treatment, and the Evolution of Disease Models

Psoriasis is a widespread chronic inflammatory skin disease. Recent advances in the molecular mechanisms of psoriasis have unveiled numerous potential therapeutic targets. However, the complex nature of psoriasis, coupled with the limitations of current research methodologies, diagnostic techniques, and gaps in knowledge, contributes to the variability in treatment efficacy among patients, recurrence following drug cessation, and therapeutic failures. Emerging technologies, including artificial intelligence, multi-omics approaches, novel modeling systems such as skin organoids, and precision medicine, are being explored to address these challenges. This review explores the latest findings in genetics, cytology, microbiology, metabolism, and molecular biology related to psoriasis pathogenesis, development, and recurrence to improve the understanding of psoriasis and find new therapeutic directions and targets. It updates the psoriasis models, diagnostic methods, and treatment while comparing their characteristics and limitations. It also provides new biomarkers and indicators to assist diagnosis and treatment. Along with traditional drugs, it explores emerging targeted drugs, cell therapies, nutrition management, microbial therapy, and traditional Chinese medicine in advancing personalized, precision medicine for psoriasis.

Understanding psoriatic disease at single-cell resolution: an update

PURPOSE OF REVIEW

This review examines recent advancements in psoriasis research through single-cell technologies, including single-cell RNA sequencing (scRNA-seq) and spatial transcriptomics. These methods have uncovered the cellular diversity underlying psoriasis, identifying immune cell, keratinocyte, and fibroblast subtypes that play pivotal roles in disease progression. Such insights are vital for addressing the complexity and heterogeneity of psoriasis, paving the way for targeted therapies.

RECENT FINDINGS

Recent studies emphasize the roles of IL-17-producing T cells (T17), keratinocytes, and fibroblasts in driving inflammation. T-cell cytokines, including IL-17A and IL-17F, induce keratinocyte hyperproliferation and amplify inflammation through an IL-36 feed-forward loop. Fibroblast subsets, such as SFRP2+ and WNT5A+/IL24+ fibroblasts, contribute to extracellular matrix remodeling and cytokine release, worsening the inflammatory environment. These studies also reveal the intricate fibroblast-keratinocyte crosstalk via the IL-17/IL-36 and PRSS3-F2R pathways. More recently, advancement with spatial transcriptomics has uncovered metabolic dysregulation in psoriatic keratinocytes, highlighting HIF1α-driven glycolysis and lactate production as critical in sustaining chronic inflammation. Furthermore, nonlesional skin from severe psoriasis patients exhibits transcriptomic changes resembling lesional skin, suggesting systemic "prelesional" state with the upregulation of lipid metabolism genes.

SUMMARY

These discoveries have significant clinical implications. Integrating single-cell and spatial technologies into psoriasis research offers promising avenues for developing tailored treatments and improving patient outcomes. Specifically, with spatial transcriptomics revealing immune signatures and cell-cell colocalization that may serve as early indicators of disease severity and systemic involvement. Targeting metabolic pathways in keratinocytes and localized immune microenvironments may enhance precision therapies for psoriasis.

How Can Spatial Transcriptomic Profiling Advance Our Understanding of Skin Diseases?

Spatial transcriptomic (ST) profiling is the mapping of gene expression within cell populations with preservation of positional context and represents an exciting new approach to develop our understanding of local and regional influences upon skin biology in health and disease. With the ability to probe from a few hundred transcripts to the entire transcriptome, multiple ST approaches are now widely available. In this paper, we review the ST field and discuss its application to dermatology. Its potential to advance our understanding of skin biology in health and disease is highlighted through the illustrative examples of 3 research areas: cutaneous aging, tumorigenesis, and psoriasis.

Techniques and analytic workflow for spatial transcriptomics and its application to allergy and inflammation

Spatial profiling, through single-cell gene-level expression data paired with cell localization, offers unprecedented biologic insights within the intact spatial context of cells in healthy and diseased tissue, adding a novel dimension to data interpretation. This review summarizes recent developments in this field, its application to allergy and inflammation, and recent single-cell resolution platforms designed for spatial transcriptomics with a focus on data processing and analyses for efficient biologic interpretation of data. By preserving spatial context, these technologies provide critical insights into tissue architecture and cellular interactions that are unattainable with traditional transcriptomics methods, such as revealing localized inflammatory cell network in atopic dermatitis and T-cell interactions in the lung in chronic obstructive pulmonary disease. Spatial profiling offers opportunities for discovering novel biomarkers, defining compartmentalization of immune responses within tissues and individual diseases, and accelerating novel discoveries toward a greater understanding of fundamental disease mechanisms and, eventually, toward the development of future targeted therapies.

Staphylococcus aureus-specific TIGIT+ Treg are present in the blood of healthy subjects - a hurdle for vaccination?

Staphylococcus aureus poses an enormous burden of morbidity and mortality worldwide. Making an efficacious vaccine has however proven extremely challenging. Due to colonizing interactions, pre-existing S. aureus-specific CD4+ T cells are often found in the human population and yet a detailed characterization of their phenotypes and how they might in turn impact vaccine efficacy are thus far unknown. Using an activation induced marker assay to sort for S. aureus-specific CD4+ T cells in an effector function-independent manner, single cell transcriptomic analysis was conducted. Remarkably, S. aureus-specific CD4+ T cells consisted not only of a broader spectrum of conventional T cells (Tcon) than previously described but also of regulatory T cells (Treg). As compared to polyclonally-activated CD4+ T cells, S. aureus-specific Tcon were enriched for the expression of the Th17-type cytokine genes IL17A, IL22 and IL26, while higher percentages of S. aureus-specific Treg expressed the T Cell Immunoreceptor with Ig and ITIM domains (TIGIT), a pleiotropic immune checkpoint. Notably, the antagonistic anti-TIGIT mAb Tiragolumab increased IL-1β production in response to S. aureus in vitro. Therefore, these results uncover the presence of S. aureus-specific TIGIT+ Treg in the blood of healthy subjects that could blunt responses to vaccination and indicate TIGIT as a potential targetable biomarker to overcome pre-exposure-induced immunosuppression.

MiR-223 within neutrophil axis promotes Th17 expansion by PI3K-AKT pathway in systemic lupus erythematosus

INTRODUCTION

Further investigation is required to determine the etiology of systemic lupus erythematosus (SLE). The aim of this study is to assess the presence of miR-223 within neutrophils in SLE and investigate its impact on the expansion of Th17 cells.

METHODS

Experiments were performed in MRL/lpr mice, which were divided into control and miR-223 knockdown (miR-223-) group. We assessed miR-223 expression within neutrophils and Th17 expansion in MRL/lpr mice and patients with SLE using RT-PCR, luciferase reporter assay, Elisa, flow cytometry analysis. Signaling pathway, RT-PCR and western blot were conducted to elucidate the mechanism by which miR-223 within neutrophils expands Th17.

RESULTS

We initially identified miR-223 as a pivotal factor in the pathogenesis of SLE in both MRL/lpr mice and SLE patients. Subsequently, knockdown of miR-223 led to a significant reduction in Th17 expansion in MRL/lpr mice. Moreover, inhibition of miR-223 effectively attenuated the recruitment and activation of neutrophils in SLE. Furthermore, we found rb6-8c5 treatment alleviated lupus symptoms of MRL/lpr mice and reduce the level of Th17. Finally, we elucidated that neutrophils potentiate the induction of Th17 through the activation of thePI3K-AKT pathway mediated by miR-223 during SLE-associated Th17 expansion.

CONCLUSION

MiR-223 within neutrophil axis contributes to Th17 expansion by PI3K-AKT pathway in SLE, and miR-223 could be a therapeutic target of SLE.

Single-cell sequencing delineates T-cell clonality and pathogenesis of the parapsoriasis disease group

BACKGROUND

Mycosis fungoides (MF), the most common cutaneous T-cell lymphoma, is often underdiagnosed in early stages because of similarities with benign dermatoses such as atopic dermatitis (AD). Furthermore, the delineation from what is called "parapsoriasis en plaque", a disease that can appear either in a small- or large-plaque form, is still controversial.

OBJECTIVE

We sought to characterize the parapsoriasis disease spectrum.

METHODS

We performed single-cell RNA sequencing of skin biopsies from patients within the parapsoriasis-to-early-stage MF spectrum, stratified for small and large plaques, and compared them to AD, psoriasis, and healthy control skin.

RESULTS

Six of 8 large-plaque lesions harbored either an expanded alpha/beta or gamma/delta T-cell clone with downregulation of CD7 expression, consistent with a diagnosis of early-stage MF. In contrast, 6 of 7 small-plaque lesions were polyclonal in nature, thereby lacking a lymphomatous phenotype, and also revealed a less inflammatory microenvironment than early-stage MF or AD. Of note, polyclonal small- and large-plaque lesions characteristically harbored a population of NPY+ innate lymphoid cells and displayed a stromal signature of complement upregulation and antimicrobial hyperresponsiveness in fibroblasts and sweat gland cells, respectively. These conditions were clearly distinct from AD or psoriasis, which uniquely harbored CD3+CRTH2+ IL-13 expressing "TH2A" cells, or strong type 17 inflammation, respectively.

CONCLUSION

These data position polyclonal small- and large-plaque parapsoriasis lesions as a separate disease entity that characteristically harbors a so far undescribed innate lymphoid cell population. We thus propose a new term, "polyclonal parapsoriasis en plaque", for this kind of lesion because they can be clearly differentiated from early- and advanced-stage MF, psoriasis, and AD on several cellular and molecular levels.

Skin immune-mesenchymal interplay within tertiary lymphoid structures promotes autoimmune pathogenesis in hidradenitis suppurativa

Hidradenitis suppurativa (HS) is a chronic, debilitating inflammatory skin disease characterized by keratinized epithelial tunnels that grow deeply into the dermis. Here, we examined the immune microenvironment within human HS lesions. Multi-omics profiling and multiplexed imaging identified tertiary lymphoid structures (TLSs) near HS tunnels. These TLSs were enriched with proliferative T cells, including follicular helper (Tfh), regulatory (Treg), and pathogenic T cells (IL17A+ and IFNG+), alongside extensive clonal expansion of plasma cells producing antibodies reactive to keratinocytes. HS fibroblasts express CXCL13 or CCL19 in response to immune cytokines. Using a microfluidic system to mimic TLS on a chip, we found that HS fibroblasts critically orchestrated lymphocyte aggregation via tumor necrosis factor alpha (TNF-α)-CXCL13 and TNF-α-CCL19 feedback loops with B and T cells, respectively; early TNF-α blockade suppressed aggregate initiation. Our findings provide insights into TLS formation in the skin, suggest therapeutic avenues for HS, and reveal mechanisms that may apply to other autoimmune settings, including Crohn's disease.

Skin-resident T Cells Contribute to the Dynamic Disease Manifestations of Psoriasis

The human skin forms a dynamic barrier to physical injuries and microbial invasion. Constant interactions between stroma and tissue-confined immune cells maintain skin homeostasis. However, the cellular interactions that maintain skin health also contribute to focal immunopathology. Psoriasis is a common disease that manifests with focal pathology induced by environmental triggers in genetically susceptible individuals. Within psoriasis plaques, cross-talk between skin-resident T cells and stroma cells leads to chronic inflammation. Inflammatory cytokines such as TNF-α, IL-17, IL-22, and IL-23 amplify the local chronic inflammation and sustain the well-demarcated thick and scaly plaques that characterize the disease. In resolved lesions, T cells remain poised for IL-17 and IL-22 production, and postinflammatory epigenetic modifications lower the threshold for initiation of local relapse. This review focuses on how tissue-resident memory T cells contribute to the onset, maintenance, resolution, and relapse of psoriasis.

The Central Roles of Keratinocytes in Coordinating Skin Immunity

The function of keratinocytes (KCs) to form a barrier and produce cytokines is well-known, but recent progress has revealed many different roles for KCs in regulation of skin immunity. In this review, we provide an update on the current understanding of how KCs communicate with microbes, immunocytes, neurons, and other cells to form an effective immune barrier. We catalog the large list of genes and metabolites of KCs that participate in host defense and discuss the mechanisms of immune crosstalk, addressing how KCs simultaneously form a physical barrier, communicate with fibroblasts, and control immune signals. Overall, the signals sent and received by KCs are an exciting group of therapeutic targets to explore in the treatment of dermatologic disorders.

Interleukin-26 expression in tuberculosis disease and its regulatory effect in macrophage polarization and intracellular elimination of Mycobacterium tuberculosis

Tuberculosis(TB), an infectious disease caused by Mycobacterium tuberculosis (Mtb) infections, remains the leading cause of mortality from a single infectious agent globally. The progression of tuberculosis disease is contingent upon the complex interplay between the host's immune system and the pathogen Mtb. Interleukin-26 (IL-26), the most recently identified cytokine belonging to the IL-10 family, exhibits both extracellular antimicrobial properties and pro-inflammatory functions. However, the precise role of IL-26 in the host immune defense against Mtb infections and intracellular killing remains largely unexplored. In this study, we observed significantly elevated IL-26 mRNA expression in peripheral blood mononuclear cells of active-TB patients compared to healthy individuals. Conversely, circulating IL-26 levels in the plasma of adult TB patients were markedly lower than those of healthy cohorts. We purified recombinant IL-26 from an E. coli expression system using the Ni-NTA resin. Upon stimulations with the recombinant IL-26, human THP1 cells exhibited rapid morphological changes characterized by increased irregular spindle shape and formation of granular structures. Treating THP1 cells with IL-26 can also lead to heightened expressions of CD80, TNF-α, and iNOS but not CD206 and Arg1 in these cells, indicating an M1 macrophage differentiation phenotype. Furthermore, our investigations revealed a dose-dependent escalation of reactive oxygen species production, decreased mitochondrial membrane potential, and enhanced autophagy flux activity in THP1 macrophages following IL-26 treatment. Moreover, our results demonstrated that IL-26 contributed to the elimination of intracellular Mycobacterium tuberculosis via orchestrated ROS production. In conclusion, our findings elucidated the role of IL-26 in the development of tuberculosis and its contributions to intracellular bacilli killing by macrophages through the induction of M1-polarization and ROS production. These insights may have significant implications for understanding the pathogenesis of tuberculosis and developing novel therapeutic strategies.

Advances in Psoriatic Disease Research: Insights From GRAPPA Pilot Research Awardees

Research progress from the Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA) pilot award program was presented and discussed at the GRAPPA 2023 annual meeting. Topics included identification of protein biomarkers associated with enthesitis in psoriatic arthritis (PsA), the role of HLA-B27 on gut microbial dysbiosis in PsA, single-cell profiling of synovial fluid vs psoriatic skin lesions in PsA, and the role of mechanotransduction in hyperactivation of transforming growth factor-β via αVβ6 integrin in psoriatic epidermis.

Skin in the game: a review of single-cell and spatial transcriptomics in dermatological research

Single-cell RNA sequencing (scRNA-seq) and spatial transcriptomics (ST) are two emerging research technologies that uniquely characterize gene expression microenvironments on a cellular or subcellular level. The skin, a clinically accessible tissue composed of diverse, essential cell populations, serves as an ideal target for these high-resolution investigative approaches. Using these tools, researchers are assembling a compendium of data and discoveries in healthy skin as well as a range of dermatologic pathophysiologies, including atopic dermatitis, psoriasis, and cutaneous malignancies. The ongoing advancement of single-cell approaches, coupled with anticipated decreases in cost with increased adoption, will reshape dermatologic research, profoundly influencing disease characterization, prognosis, and ultimately clinical practice.

A Comprehensive Network Map of Interleukin-26 Signaling Pathway

Interleukin-26 (IL-26) is a cytokine that belongs to the IL-20 subfamily and is primarily expressed in T helper 1 cells and Th17 memory CD4+ cells. Its receptor complex, consisting of IL-20R1 and IL-10R2, activates a signaling pathway involving several proteins such as Janus kinase 1 and tyrosine-protein kinase, signal transducer and activator of transcription (STAT) 1, and STAT3. This leads to the initiation of downstream signaling cascades that play a crucial role in various biological processes, including inflammation, immune response regulation, atopic dermatitis, macrophage differentiation, osteoclastogenesis, antibacterial host defense, anti-apoptosis, and tumor growth. In this study, we curated literature data pertaining to IL-26 signaling. The curated map includes a total of seven activation/inhibition events, 16 catalysis events, 33 gene regulation events, 25 protein expression types, two transport events, and three molecular associations.

Alterations in the Skin Microbiome in Dermatologic Diseases and with External Exposures: CME Part 2

In Part I of our CME we reviewed the skin microbiome in healthy individuals. Part II reviews the evolving understanding of alterations in the skin microbiome in specific human diseases. We also discuss how the skin microbiome can change with environmental exposures and medications such as antibiotics as well as ongoing research on microbiome-based interventions.

Single-cell technologies in psoriasis

Psoriasis is a chronic and recurrent inflammatory skin disorder. The primary manifestation of psoriasis arises from disturbances in the cutaneous immune microenvironment, but the specific functions of the cellular components within this microenvironment remain unknown. Recent advancements in single-cell technologies have enabled the detection of multi-omics at the level of individual cells, including single-cell transcriptome, proteome, and metabolome, which have been successfully applied in studying autoimmune diseases, and other pathologies. These techniques allow the identification of heterogeneous cell clusters and their varying contributions to disease development. Considering the immunological traits of psoriasis, an in-depth exploration of immune cells and their interactions with cutaneous parenchymal cells can markedly advance our comprehension of the mechanisms underlying the onset and recurrence of psoriasis. In this comprehensive review, we present an overview of recent applications of single-cell technologies in psoriasis, aiming to improve our understanding of the underlying mechanisms of this disorder.

Cytokines in psoriasis: From pathogenesis to targeted therapy

Psoriasis is a multifactorial disease that affects 0.84% of the global population and it can be associated with disabling comorbidities. As patients present with thick scaly lesions, psoriasis was long believed to be a disorder of keratinocytes. Psoriasis is now understood to be the outcome of the interaction between immunological and environmental factors in individuals with genetic predisposition. While it was initially thought to be solely mediated by cytokines of type-1 immunity, namely interferon-γ, interleukin-2, and interleukin-12 because it responds very well to cyclosporine, a reversible IL-2 inhibitor; the discovery of Th-17 cells advanced the understanding of the disease and helped the development of biological therapy. This article aims to provide a comprehensive review of the role of cytokines in psoriasis, highlighting areas of controversy and identifying the connection between cytokine imbalance and disease manifestations. It also presents the approved targeted treatments for psoriasis and those currently under investigation.

IL-26 Potentiates Type 2 Skin Inflammation in the Presence of IL-1β

Atopic dermatitis (AD) is a debilitating inflammatory skin disorder. Biologics targeting the IL-4/IL-13 axis are effective in AD, but there is still a large proportion of patients who do not respond to IL-4R blockade. Further exploration of potentially pathogenic T-cell-derived cytokines in AD may lead to new effective treatments. This study aimed to investigate the downstream effects of IL-26 on skin in the context of type 2 skin inflammation. We found that IL-26 alone exhibited limited inflammatory activity in the skin. However, in the presence of IL-1β, IL-26 potentiated the secretion of TSLP, CXCL1, and CCL20 from human epidermis through Jak/signal transducer and activator of transcription signaling. Moreover, in an in vivo AD-like skin inflammation model, IL-26 exacerbated skin pathology and locally increased type 2 cytokines, most notably of IL13 in skin T helper cells. Neutralization of IL-1β abrogated IL-26-mediated effects, indicating that the presence of IL-1β is required for full IL-26 downstream action in vivo. These findings suggest that the presence of IL-1β enables IL-26 to be a key amplifier of inflammation in the skin. As such, IL-26 may contribute to the development and pathogenesis of inflammatory skin disorders such as AD.

Immunobiology of IL-26

T helper 17 (Th17) cells produce a set of cytokines that include IL-17 family members, IL-21, IL-22, and IL-26. These cytokines all contribute to the classic function of Th17 cells in combatting extracellular infection and promoting inflammation in autoimmune diseases. However, of the Th17 cytokines, only IL-26 has direct antimicrobial activity against microbes and can activate a broad range of immune cells through its ability to bind DNA and trigger pattern recognition receptors. It is noteworthy that IL-26 is produced by mammalian cells, including human Th17 cells, but is absent in rodents. As such, IL-26 is a potential therapeutic target to augment host immune responses against microbial pathogens but also to prevent inflammation and tissue damage in a variety of autoimmune diseases.

Identification of Critical Immune Regulators and Potential Interactions of IL-26 in Riemerella anatipestifer-Infected Ducks by Transcriptome Analysis and Profiling

Riemerella anatipestifer (RA) is an economically important pathogen in the duck industry worldwide that causes high mortality and morbidity in infected birds. We previously found that upregulated IL-17A expression in ducks infected with RA participates in the pathogenesis of the disease, but this mechanism is not linked to IL-23, which primarily promotes Th17 cell differentiation and proliferation. RNA sequencing analysis was used in this study to investigate other mechanisms of IL-17A upregulation in RA infection. A possible interaction of IL-26 and IL-17 was discovered, highlighting the potential of IL-26 as a novel upstream cytokine that can regulate IL-17A during RA infection. Additionally, this process identified several important pathways and genes related to the complex networks and potential regulation of the host immune response in RA-infected ducks. Collectively, these findings not only serve as a roadmap for our understanding of RA infection and the development of new immunotherapeutic approaches for this disease, but they also provide an opportunity to understand the immune system of ducks.

Increased interleukin-26 in the peripheral joints of patients with axial spondyloarthritis and psoriatic arthritis, co-localizing with CD68-positive synoviocytes

Objectives

IL26 levels are elevated in the blood and synovial fluid of patients with inflammatory arthritis. IL26 can be produced by Th17 cells and locally within joints by tissue-resident cells. IL26 induces osteoblast mineralization in vitro. As osteoproliferation and Th17 cells are important factors in the pathogenesis of axial spondyloarthritis (axSpA), we aimed to clarify the cellular sources of IL26 in spondyloarthritis.

Methods

Serum, peripheral blood mononuclear cells (n = 15-35) and synovial tissue (n = 3-9) of adult patients with axSpA, psoriatic arthritis (PsA) and rheumatoid arthritis (RA) and healthy controls (HCs, n = 5) were evaluated by ELISA, flow cytometry including PrimeFlow assay, immunohistochemistry and immunofluorescence and quantitative PCR.

Results

Synovial tissue of axSpA patients shows significantly more IL26-positive cells than that of HCs (p < 0.01), but numbers are also elevated in PsA and RA patients. Immunofluorescence shows co-localization of IL26 with CD68, but not with CD3, SMA, CD163, cadherin-11, or CD90. IL26 is elevated in the serum of RA and PsA (but not axSpA) patients compared with HCs (p < 0.001 and p < 0.01). However, peripheral blood CD4+ T cells from axSpA and PsA patients show higher positivity for IL26 in the PrimeFlow assay compared with HCs. CD4+ memory T cells from axSpA patients produce more IL26 under Th17-favoring conditions (IL-1β and IL-23) than cells from PsA and RA patients or HCs.

Conclusion

IL26 production is increased in the synovial tissue of SpA and can be localized to CD68+ macrophage-like synoviocytes, whereas circulating IL26+ Th17 cells are only modestly enriched. Considering the osteoproliferative properties of IL26, this offers new therapeutic options independent of Th17 pathways.

Neutrophil IL-26 fuels autoinflammation

Pustular psoriasis is an inflammatory skin disease with features of neutrophil-mediated sterile autoinflammation. In this issue of JEM, Baldo et al. (https://doi.org/10.1084/jem.20231464) show that this autoinflammation is driven by a vicious cycle through neutrophil-derived IL-26.

Theoretical Studies of DNA Microarray Present Potential Molecular and Cellular Interconnectivity of Signaling Pathways in Immune System Dysregulation

Autoimmunity is defined as the inability to regulate immunological activities in the body, especially in response to external triggers, leading to the attack of the tissues and organs of the host. Outcomes include the onset of autoimmune diseases whose effects are primarily due to dysregulated immune responses. In past years, there have been cases that show an increased susceptibility to other autoimmune disorders in patients who are already experiencing the same type of disease. Research in this field has started analyzing the potential molecular and cellular causes of this interconnectedness, bearing in mind the possibility of advancing drugs and therapies for the treatment of autoimmunity. With that, this study aimed to determine the correlation of four autoimmune diseases, which are type 1 diabetes (T1D), psoriasis (PSR), systemic sclerosis (SSc), and systemic lupus erythematosus (SLE), by identifying highly preserved co-expressed genes among datasets using WGCNA. Functional annotation was then employed to characterize these sets of genes based on their systemic relationship as a whole to elucidate the biological processes, cellular components, and molecular functions of the pathways they are involved in. Lastly, drug repurposing analysis was performed to screen candidate drugs for repositioning that could regulate the abnormal expression of genes among the diseases. A total of thirteen modules were obtained from the analysis, the majority of which were associated with transcriptional, post-transcriptional, and post-translational modification processes. Also, the evaluation based on KEGG suggested the possible role of TH17 differentiation in the simultaneous onset of the four diseases. Furthermore, clomiphene was the top drug candidate for regulating overexpressed hub genes; meanwhile, prilocaine was the top drug for regulating under-expressed hub genes. This study was geared towards utilizing transcriptomics approaches for the assessment of microarray data, which is different from the use of traditional genomic analyses. Such a research design for investigating correlations among autoimmune diseases may be the first of its kind.

Transdermal delivery of Fn14 siRNA using a novel composite ionic liquid for treatment of psoriasis-like skin lesions

Psoriasis is a chronic inflammatory skin disease characterised by the abnormal proliferation of keratinocytes and dysregulation of immune cells. The upregulation of fibroblast growth factor-inducible molecule 14 (Fn14) in psoriatic lesions has been linked to the development of psoriasis. Transdermal delivery of siRNAs for Fn14 inhibition is challenging. In this study, we developed a composite ionic liquid (CIL) for the transdermal delivery of Fn14 siRNA (siFn14) into keratinocytes, with the aim of modulating the inflammatory response associated with psoriasis. The results showed that CIL-siFn14 effectively suppressed Fn14 expression, resulting in a reduction in both the Psoriasis Area and Severity Index (PASI) score and skin thickness. Furthermore, CIL-siFn14 effectively inhibited the abnormal proliferation of keratinocytes, decreased the production of inflammatory factors associated with psoriasis, prevented the over-activation of CD4+ and CD8+ T cells, and restored the balance of Type 1 T helper (Th1), Th2, Th17 and Treg cells. In conclusion, our findings unveiled the critical role of Fn14 in the pathogenesis of psoriasis and demonstrated the potential of CIL-siFn14 as a novel and effective topical treatment for its management.

Disentangling the complexity of psoriasis in the post-genome-wide association era

In recent years, genome-wide association studies (GWAS) have been instrumental in unraveling the genetic architecture of complex diseases, including psoriasis. The application of large-scale GWA studies in psoriasis has illustrated several associated loci that participate in the cutaneous inflammation, however explaining a fraction of the disease heritability. With the advent of high-throughput sequencing technologies and functional genomics approaches, the post-GWAS era aims to unravel the functional mechanisms underlying the inter-individual variability in psoriasis patients. In this review, we present the key advances of psoriasis GWAS in under-represented populations, rare, non-coding and structural variants and epistatic phenomena that orchestrate the interplay between different cell types. We further review the gene-gene and gene-environment interactions contributing to the disease predisposition and development of comorbidities through Mendelian randomization studies and pleiotropic effects of psoriasis-associated loci. We finally examine the holistic approaches conducted in psoriasis through system genetics and state-of-the-art transcriptomic analyses, discussing their potential implication in the expanding field of precision medicine and characterization of comorbidities.