IL-1β and IL-17 in cutaneous lupus erythematous skin biopsies: could immunohistochemicals indicate a tendency towards systemic involvement?

BACKGROUND

Only a fraction of patients with cutaneous lupus erythematosus (CLE) will eventually progress toward systemic disease (SLE).

OBJECTIVE

To find inflammatory biomarkers which could predict the progression of cutaneous lupus erythematosus (CLE) into systemic lupus erythematosus (SLE) using immunohistochemical (IHC) assays.

METHODS

Immunohistochemical markers for cytotoxic, inflammatory, and anti-inflammatory responses and morphometric methods were applied to routine paraffin sections of skin biopsies, taken from lesions of 59 patients with discoid lupus, subacute lupus, and lupus tumidus. For the diagnosis of SLE, patients were classified by both the American College of Rheumatology (ACR-82) and the Systemic Lupus International Collaborating Clinics (SLICC-12) systems.

RESULTS

Skin samples from CLE/SLE+patients presented higher expression of IL-1β (ARC-82: p=0.024; SLICC-12: p=0.0143) and a significantly higher number of cells marked with granzyme B and perforin (ARC: p=0.0097; SLICC-12: p=0.0148). Biopsies from CLE/SLE- individuals had higher expression of IL-17 (ARC-82: p=0.0003; SLICC-12: p=0.0351) and presented a positive correlation between the density of granzyme A+and FoxP3+ cells (ARC-82: p=0.0257; SLICC-12: p=0.0285) and CD8+ cells (ARC-82: p=0.0075; SLICC-12: p=0.0102), as well as between granulysin-positive and CD8+ cells (ARC-82: p=0.0024; SLICC-12: p=0.0116).

STUDY LIMITATIONS

Patients were evaluated at a specific point in their evolution and according to the presence or not of systemic disease. The authors cannot predict how many more, from each group, would have evolved towards SLE in the following years.

CONCLUSIONS

In this cohort, immunohistochemical findings suggested that patients with a tendency to systemic disease will show strong reactivity for IL-1β, while those with purely cutaneous involvement will tend to express IL-17 more intensely.

Identification of PANoptosis-related biomarkers and immune infiltration characteristics in psoriasis

BACKGROUND

PANoptosis may play a vital role in psoriasis. We investigated the relationship between PANoptosis in psoriasis.

METHODS

Genes information was mainly obtained from GeneCards and the gene expression omnibus database. Genefunctions identification was based on gene ontology and Kyoto Encyclopedia of Genes and Genomes analyses. Gene set enrichment analysis was used to identify enriched signaling pathways in psoriasis. We constructed PPI networks using the search tool for the retrieval of interacting genes database and Cytoscape and explored mRNA-miRNA, mRNA-TF, and mRNA-drug interaction networks. Receiver operating characteristic curves were performed to screen potential biomarkers among these hub genes. Immune cell infiltration was analyzed using the Pearson algorithm, and the correlation between immune-cell abundance and PANoptosis-related differentially expressed gene (PDGs) was investigated.

RESULTS

We identified 10 PDGs, which were mainly involved in pyroptosis, cytokine-mediated signaling pathways, Salmonella infection and NOD-like receptor signaling pathway. The activated pathways were mostly proinflammatory and immunoregulatory pathways between immune cells. BAK1, CASP4, IL18, and IRF1 were identified as hub genes in the mRNA-miRNA network, and BAK1, IRF1, and PYCARD were hub genes in the mRNA-TF network. CASP1 was found to be the most targeted gene by drugs or molecular compounds. We found PDGs were positively associated with proinflammatory immune cell infiltration and negatively associated with anti-inflammatory or regulatory immune cells.

CONCLUSION

We confirmed the role of PANoptosis in psoriasis for the first time and predicted hub genes and immune characteristics, which provides new ideas for further investigation of psoriasis on pathogenic mechanisms and therapeutic strategies.

Construction of regulatory network for alopecia areata progression and identification of immune monitoring genes based on multiple machine-learning algorithms

Objectives

Alopecia areata (AA) is an autoimmune-related non-cicatricial alopecia, with complete alopecia (AT) or generalized alopecia (AU) as severe forms of AA. However, there are limitations in early identification of AA, and intervention of AA patients who may progress to severe AA will help to improve the incidence rate and prognosis of severe AA.

Methods

We obtained two AA-related datasets from the gene expression omnibus database, identified the differentially expressed genes (DEGs), and identified the module genes most related to severe AA through weighted gene co-expression network analysis. Functional enrichment analysis, construction of a protein-protein interaction network and competing endogenous RNA network, and immune cell infiltration analysis were performed to clarify the underlying biological mechanisms of severe AA. Subsequently, pivotal immune monitoring genes (IMGs) were screened through multiple machine-learning algorithms, and the diagnostic effectiveness of the pivotal IMGs was validated by receiver operating characteristic.

Results

A total of 150 severe AA-related DEGs were identified; the upregulated DEGs were mainly enriched in immune response, while the downregulated DEGs were mainly enriched in pathways related to hair cycle and skin development. Four IMGs (LGR5, SHISA2, HOXC13, and S100A3) with good diagnostic efficiency were obtained. As an important gene of hair follicle stem cells stemness, we verified in vivo that LGR5 downregulation may be an important link leading to severe AA.

Conclusion

Our findings provide a comprehensive understanding of the pathogenesis and underlying biological processes in patients with AA, and identification of four potential IMGs, which is helpful for the early diagnosis of severe AA.

Role of the granzyme family in rheumatoid arthritis: Current Insights and future perspectives

Rheumatoid arthritis (RA) is a complex autoimmune disease characterized by chronic inflammation that affects synovial tissues of multiple joints. Granzymes (Gzms) are serine proteases that are released into the immune synapse between cytotoxic lymphocytes and target cells. They enter target cells with the help of perforin to induce programmed cell death in inflammatory and tumor cells. Gzms may have a connection with RA. First, increased levels of Gzms have been found in the serum (GzmB), plasma (GzmA, GzmB), synovial fluid (GzmB, GzmM), and synovial tissue (GzmK) of patients with RA. Moreover, Gzms may contribute to inflammation by degrading the extracellular matrix and promoting cytokine release. They are thought to be involved in RA pathogenesis and have the potential to be used as biomarkers for RA diagnosis, although their exact role is yet to be fully elucidated. The purpose of this review was to summarize the current knowledge regarding the possible role of the granzyme family in RA, with the aim of providing a reference for future research on the mechanisms of RA and the development of new therapies.

Targeting interleukin-17 enhances tumor response to immune checkpoint inhibitors in colorectal cancer

Although immune checkpoint inhibitors (ICIs) have gained much attention in managing cancer, only a minority of patients, especially those with tumors that have been classified as immunologically "cold" such as microsatellite stable (MSS) colorectal cancers (CRC), experience clinical benefit from ICIs. Surprisingly, interleukin-17 (IL-17) and its primary source Th17 are enriched in CRC and inversely associated with patient outcome. Our previous study revealed that IL-17A could upregulate programmed death-ligand 1 (PD-L1) expression and impede the efficacy of immunotherapy. IL-17, therefore, can be a possible target to sensitize tumor cells to ICIs. The detailed clinical results from our trial, which is the first to show the benefits of the combination of anti-PD-1 with anti-IL-17 therapy for MSS CRC, have also been presented. In this review, we highlight the role of IL-17 in ICIs resistance and summarize the current clinical evidence for the use of combination therapy. Directions for future strategies to warm up immunologically "cold" MSS CRCs have also been proposed.

Expression and activity of IL-17 receptor subunits in human cutaneous cells as targets for anti-IL-17 therapeutic antibodies

The key players in different chronic inflammatory skin diseases are cytokines belonging to the IL-17 group, IL-17 receptors and a T helper cell population, Th17 cells. Successful therapeutic strategies that target either IL-17 or the major IL-17 receptor IL-17RA have confirmed the immune-pathogenic pathway. To study the IL-17-ligand - receptor axis at the molecular level, a number of cutaneous cell types from healthy human subjects has been cultured and analyzed for the expression of IL-17 receptors. IL-17RA was the most abundantly expressed receptor type in keratinocytes, epidermal stem cells, fibroblasts, mesenchymal stem cells, hemo- and lymphovascular endothelial cells. IL-17RC and IL-17RD showed moderate expression, while the genes for IL-17RB and IL-17RE were poorly expressed. In none of the investigated cell types, IL-17 ligands caused an increased expression level of the five receptor types in time- and dose-dependent experiments. No evidence for IL-17A, -C, -E or -F induced signal transduction cascades could be obtained by a qRT-PCR and western blot analyses. Further studies are necessary to identify relevant co-stimulating factors from IL-17 subtypes under physiological and pathophysiological conditions.

Osteocyte-Related Cytokines Regulate Osteoclast Formation and Bone Resorption

The process of bone remodeling is the result of the regulated balance between bone cell populations, namely bone-forming osteoblasts, bone-resorbing osteoclasts, and the osteocyte, the mechanosensory cell type. Osteoclasts derived from the hematopoietic stem cell lineage are the principal cells involved in bone resorption. In osteolytic diseases such as rheumatoid arthritis, periodontitis, and osteoporosis, the balance is lost and changes in favor of bone resorption. Therefore, it is vital to elucidate the mechanisms of osteoclast formation and bone resorption. It has been reported that osteocytes express Receptor activator of nuclear factor κΒ ligand (RANKL), an essential factor for osteoclast formation. RANKL secreted by osteocytes is the most important factor for physiologically supported osteoclast formation in the developing skeleton and in pathological bone resorption such as experimental periodontal bone loss. TNF-α directly enhances RANKL expression in osteocytes and promotes osteoclast formation. Moreover, TNF-α enhances sclerostin expression in osteocytes, which also increases osteoclast formation. These findings suggest that osteocyte-related cytokines act directly to enhance osteoclast formation and bone resorption. In this review, we outline the most recent knowledge concerning bone resorption-related cytokines and discuss the osteocyte as the master regulator of bone resorption and effector in osteoclast formation.

Granzyme A in Chikungunya and Other Arboviral Infections

Granzyme A (GzmA) is secreted by cytotoxic lymphocytes and has traditionally been viewed as a mediator of cell death. However, a growing body of data suggests the physiological role of GzmA is promotion of inflammation. Here, we show that GzmA is significantly elevated in the sera of chikungunya virus (CHIKV) patients and that GzmA levels correlated with viral loads and disease scores in these patients. Serum GzmA levels were also elevated in CHIKV mouse models, with NK cells the likely source. Infection of mice deficient in type I interferon responses with CHIKV, Zika virus, or dengue virus resulted in high levels of circulating GzmA. We also show that subcutaneous injection of enzymically active recombinant mouse GzmA was able to mediate inflammation, both locally at the injection site as well as at a distant site. Protease activated receptors (PARs) may represent targets for GzmA, and we show that treatment with PAR antagonist ameliorated GzmA- and CHIKV-mediated inflammation.

Increased frequency of activated CD8+ T cell effectors in patients with psoriatic arthritis

The aim of this study is to identify subsets of T cells differentially represented in the circulation of patients with psoriatic arthritis and to evaluate the possibility that they can recirculate between peripheral blood and the inflamed joints. We analyzed the phenotype and cytokine expression in circulating CD8+ and CD4+ T cells in 69 subjects: 28 with cutaneous psoriasis, 15 patients with psoriatic arthritis, and 26 healthy subjects. In the circulation, the percentage of each subset was compared among the groups and correlation was calculated with the serum concentration of C-reactive protein. To investigate the migration of T cells towards the inflamed joints, we performed a transwell migration assay towards patient serum and synovial fluid. In selected patients we analyzed in parallel T cells from peripheral blood and from synovial fluid. In the circulation, we found increased percentage of CD8+ CCR6+ T cell effectors expressing CD69 and of IL-17-producing T cells in patients with psoriatic arthritis. CD8+ effector/effector memory T cells showed increased migration towards synovial fluid. Finally, in synovial fluid we found accumulation of CXCR3+ CD8+ T cells and CD69+ cells. CD4+ T cells in the two compartments shared many similarities with CD8+ T cells. The results indicate a role for memory T cell effectors in systemic and joint manifestations of psoriatic arthritis.

A skewed pool of resident T cells triggers psoriasis-associated tissue responses in never-lesional skin from patients with psoriasis

BACKGROUND

Resident T cells are implicated in the maintenance and recurrence of psoriatic lesions. Whether skin that has not yet experienced psoriasis in patients with established disease harbors pathogenic T cells is less investigated.

OBJECTIVE

We sought to analyze the composition of resident T cells and T cell-driven tissue responses in skin never affected by psoriasis from patients with mild disease.

METHODS

Never-lesional skin from patients with psoriasis (NLP) was collected from those with mild disease. T-cell profiles were assessed by using confocal imaging and flow cytometry. Tissue responses to T-cell stimulation were measured by using multiplex and NanoString technology.

RESULTS

T-cell activation ex vivo triggered psoriasiform and type I interferon tissue responses in NLP psoriasis. Accordingly, keratinocytes from NLP responded to IFN-γ stimulation with myxovirus 1 (MX1) expression and IFN-α release. Additionally, CCR6-expressing resident T cells poised to produce IFN-γ and IL-17 were enriched in epidermis from NLP, whereas dermal tissue responses and T-cell compositions were similar to those in healthy skin. Finally, keratinocytes from NLP exposed to IL-17 and skin explants exposed to common fungal antigens responded with upregulation of the CCR6 ligand CCL20.

CONCLUSION

Epidermal resident T cells capable of triggering psoriasiform tissue responses accumulate in epidermis from NLP. Our global analysis of NLP reveals that microbial interplay with genetically predisposed keratinocytes might shape the local pool of resident T cells.

Resident T Cells in Resolved Psoriasis Steer Tissue Responses that Stratify Clinical Outcome

Psoriasis is driven by focal disruptions of the immune-homeostasis in human skin. Local relapse following cessation of therapy is common and unpredictable, which complicates clinical management of psoriasis. We have previously shown that pathogenic resident T cells accumulate in active and resolved psoriasis, but whether these cells drive psoriasiform tissue reactions is less clear. Here, we activated T cells within skin explants using the pan-T cell activating antibody OKT-3. To explore if T cells induced different tissue response patterns in healthy and psoriasis afflicted skin, transcriptomic analyses were performed with RNA-sequencing and Nanostring. Core tissue responses dominated by IFN-induced pathways were triggered regardless of the inflammatory status of the skin. In contrast, pathways induced by IL-17A, including Defensin beta 2 and keratinocyte differentiation markers, were activated in psoriasis samples. An integrated analysis of IL-17A and IFN-related responses revealed that IL-17 dominated tissue response correlated with early relapse following UVB treatment. Stratification of tissue responses to T cell activation in resolved lesions could potentially offer individualized prediction of disease relapse during long-term immunomodulatory treatment.

Human Langerhans Cells with Pro-inflammatory Features Relocate within Psoriasis Lesions

Psoriasis is a common skin disease that presents with well-demarcated patches of inflammation. Recurrent disease in fixed areas of the skin indicates a localized disease memory that is preserved in resolved lesions. In line with such concept, the involvement of tissue-resident immune cells in psoriasis pathology is increasingly appreciated. Langerhans cells (LCs) are perfectly placed to steer resident T cells and local tissue responses in psoriasis. Here, we present an overview of the current knowledge of LCs in human psoriasis, including findings that highlight pro-inflammatory features of LCs in psoriasis lesions. We also review the literature on conflicting data regarding LC localization and functionality in psoriasis. Our review highlights that further studies are needed to elucidate the molecular mechanisms that drive LCs functionality in inflammatory diseases.