Gut symbionts alleviate MASH through a secondary bile acid biosynthetic pathway.

The gut microbiota has been found to play an important role in the progression of metabolic dysfunction-associated steatohepatitis (MASH), but the mechanisms have not been established. Here, by developing a click-chemistry-based enrichment strategy, we identified several microbial-derived bile acids, including the previously uncharacterized 3-succinylated cholic acid (3-sucCA), which is negatively correlated with liver damage in patients with liver-tissue-biopsy-proven metabolic dysfunction-associated fatty liver disease (MAFLD). By screening human bacterial isolates, we identified Bacteroides uniformis strains as effective producers of 3-sucCA both in vitro and in vivo. By activity-based protein purification and identification, we identified an enzyme annotated as ß-lactamase in B. uniformis responsible for 3-sucCA biosynthesis. Furthermore, we found that 3-sucCA is a lumen-restricted metabolite and alleviates MASH by promoting the growth of Akkermansia muciniphila. Together, our data offer new insights into the gut microbiota-liver axis that may be leveraged to augment the management of MASH.

Interleukin-38 promotes skin tumorigenesis in an IL-1Rrp2-dependent manner.

Interleukin-38 (IL-38) is strongly associated with chronic inflammatory diseases; however, its role in tumorigenesis is poorly understood. We demonstrated that expression of IL-38, which exhibits high expression in the skin, is downregulated in human cutaneous squamous cell carcinoma and 7,12-dimethylbenzanthracene/12-O-tetradecanoyl phorbol-13-acetate-induced mouse skin tumorigenesis. IL-38 keratinocyte-specific knockout mice displayed suppressed skin tumor formation and malignant progression. Keratinocyte-specific deletion of IL-38 was associated with reduced expression of inflammatory cytokines, leading to reduced myeloid cell infiltration into the local tumor microenvironment. IL-38 is dispensable for epidermal mutagenesis, but IL-38 keratinocyte-specific deletion reduces proliferative gene expression along with epidermal cell proliferation and hyperplasia. Mechanistically, we first demonstrated that IL-38 activates the c-Jun N-terminal kinase (JNK)/activator protein 1 signal transduction pathway to promote the expression of cancer-related inflammatory cytokines and proliferation and migration of tumor cells in an IL-1 receptor-related protein 2 (IL-1Rrp2)-dependent manner. Our findings highlight the role of IL-38 in the regulation of epidermal cell hyperplasia and pro-tumorigenic microenvironment through IL-1Rrp2/JNK and suggest IL-38/IL-1Rrp2 as a preventive and potential therapeutic target in skin cancer.

Akkermansia muciniphila plays critical roles in host health.

Akkermansia muciniphila, an intestinal microorganism, belongs to Verrucomicrobia, one of the most abundant microorganisms in the mammalian gut. It is a mucin-degrading bacterium that can colonise intestines of mammals such as humans and mice by utilising mucin as the only nitrogen and carbon source. When A. muciniphila colonises the intestine, its metabolites interact with the intestinal barrier, affecting host health by consolidating the intestinal barrier, regulating metabolic functions of the intestinal and circulatory systems, and regulating immune functions. This review summarised the mechanisms of A. muciniphila-host interactions that are relevant to host health. We focussed on characteristics of A. muciniphila in relation to its metabolites to provide a comprehensive understanding of A. muciniphila and its effects on host health and disease processes.

Serum lncRNA THRIL predicts benign and malignant pulmonary nodules and promotes the progression of pulmonary malignancies.

BACKGROUND: This project aimed to research the significance of THRIL in the diagnosis of benign and malignant solitary pulmonary nodules (SPNs) and to investigate the role of THRIL/miR-99a in malignant SPNs. METHODS: The study groups consisted of 169 patients with SPN and 74 healthy subjects. The differences in THRIL levels were compared between the two groups and the healthy group. The receiver operating characteristic curve (ROC) was utilized to analyze the THRIL's significance in detecting benign and malignant SPN. Pearson correlation and binary regression coefficients represented the association between THRIL and SPN. CCK-8 assay, Transwell assay, and flow cytometry were utilized to detect the regulatory effect of THRIL silencing. The interaction between THRIL, miR-99a, and IGF1R was confirmed by the double luciferase reporter gene. RESULTS: There were differences in THRIL expression in the healthy group, benign SPN group, and malignant SPN group. High accuracy of THRIL in the diagnosis of benign SPN and malignant SPN was observed. THRIL was associated with the development of SPN. The expression of THRIL was upregulated and miR-99a was downregulated in lung cancer cells. The double luciferase report experiment confirmed the connections between THRIL/miR-99a/IGF1R. Silencing THRIL could suppress cell proliferation, migration, and invasion and promote cell apoptosis by binding miR-99a. CONCLUSION: The detection of THRIL in serum is useful for the assessment of malignant SPN. THRIL can regulate the expression of IGF1R through miR-99a, thereby promoting the growth of lung cancer cells and inhibiting apoptosis.

Pathogenesis, multi-omics research, and clinical treatment of psoriasis.

Psoriasis is a common inflammatory skin disease involving interactions between keratinocytes and immune cells that significantly affects the quality of life. It is characterized by hyperproliferation and abnormal differentiation of keratinocytes and excessive infiltration of immune cells in the dermis and epidermis. The immune mechanism underlying this disease has been elucidated in the past few years. Research shows that psoriasis is regulated by the complex interactions among immune cells, such as keratinocytes, dendritic cells, T lymphocytes, neutrophils, macrophages, natural killer cells, mast cells, and other immune cells. An increasing number of signaling pathways have been found to be involved in the pathogenesis of psoriasis, which has prompted the search for new treatment targets. In the past decades, studies on the pathogenesis of psoriasis have focused on the development of targeted and highly effective therapies. In this review, we have discussed the relationship between various types of immune cells and psoriasis and summarized the major signaling pathways involved in the pathogenesis of psoriasis, including the PI3K/AKT/mTOR, JAK-STAT, JNK, and WNT pathways. In addition, we have discussed the results of the latest omics research on psoriasis and the epigenetics of the disease, which provide insights regarding its pathogenesis and therapeutic prospects; we have also summarized its treatment strategies and observations of clinical trials. In this paper, the various aspects of psoriasis are described in detail, and the limitations of the current treatment methods are emphasized. It is necessary to improve and innovate treatment methods from the molecular level of pathogenesis, and further provide new ideas for the treatment and research of psoriasis.

PKCα replaces AMPK to regulate mitophagy: Another PEDF role on ischaemic cardioprotection.

Both decreased autophagy positive regulator AMP activated protein kinase (AMPK) level and promoted mitophagy are observed in oxygen-glucose deprivation (OGD) cardiomyocytes treated with pigment epithelium-derived factor (PEDF). This contradictory phenomenon and its underlying mechanisms have not been thoroughly elucidated. Our previous study reveals that PEDF increases the protein kinase Cα (PKCα) and phospho-PKCα (p-PKCα) contents to promote mitophagy. Thus, we investigated the association between PKCα and mitophagy. Here we identify an interaction between PKCα and Unc-51-like kinase 1 (ULK1), essential component of mitophagy. Further analyses show this is a direct interaction within a domain of ULK1 that termed the serine/threonine-rich domain (S/T domain). Notably, a deletion mutant ULK1 that lacks the binding domain is defective in mediating PEDF-induced mitophagy. Furthermore, we demonstrate that ULK1 is phosphorylated at Ser317/555/777 and Raptor is also phosphorylated by phospho-PKCα. Phospho-ULK1 (p-ULK1) at these sites are all essential for PEDF-induced mitophagy and reduce the release of mitochondrial ROS and DNA. This study therefore identifies a previously uncharacterized interaction between the ULK1 and PKCα that can replace the AMPK-dependent mitophagy processes.

Chronic Stress Dampens Lactobacillus Johnsonii-Mediated Tumor Suppression to Enhance Colorectal Cancer Progression.

Colorectal cancer development and outcome are impacted by modifiable risk factors, including psychologic stress. The gut microbiota has also been shown to be linked to psychologic factors. Here, we found a marked deteriorative effect of chronic stress in multiple colorectal cancer models, including chemically induced (AOM/DSS), genetically engineered (APCmin/+), and xenograft tumor mouse models. RNA sequencing data from colon tissues revealed that expression of stemness-related genes was upregulated in the stressed colorectal cancer group by activated ß-catenin signaling, which was further confirmed by results from ex vivo organoid analyses as well as in vitro and in vivo cell tumorigenicity assays. 16S rRNA sequencing of the gut microbiota showed that chronic stress disrupted gut microbes, and antibiotic treatment and fecal microbiota transplantation abolished the stimulatory effects of chronic stress on colorectal cancer progression. Stressed colorectal cancer mice displayed a significant decrease in Lactobacillus johnsonii (L. johnsonii) abundance, which was inversely correlated with tumor load. Moreover, protocatechuic acid (PCA) was identified as a beneficial metabolite produced by L. johnsonii based on metabolome sequencing and LC/MS-MS analysis. Replenishment of L. johnsonii or PCA blocked chronic stress-induced colorectal cancer progression by decreasing ß-catenin expression. Furthermore, PCA activated the cGMP pathway, and the cGMP agonist sildenafil abolished the effects of chronic stress on colorectal cancer. Altogether, these data identify that stress impacts the gut microbiome to support colorectal cancer progression. SIGNIFICANCE: Chronic stress stimulates cancer stemness by reducing the intestinal abundance of L. johnsonii and its metabolite PCA to enhance ß-catenin signaling, forming a basis for potential strategies to circumvent stress-induced cancer aggressiveness. See related commentary by McCollum and Shah, p. 645.

EDIL3 alleviates Mannan-induced psoriatic arthritis by slowing the intracellular glycolysis process in mononuclear-derived dendritic cells.

Psoriatic arthritis (PsA) is an immune-mediated, chronic inflammatory joint disease that commonly occurs as a complication of psoriasis. EGF-like repeats and discoidal I-like domain 3 (EDIL3) is a secreted protein with multiple structural domains and associated with various physiological functions. In this study, we employed a mannan-induced psoriatic arthritis model to investigate the impact of EDIL3 on PsA pathogenesis. Notably, a downregulation of EDIL3 expression was observed in the PsA model, which correlated with increased disease severity. EDIL3 knockout mice exhibited a more severe phenotype of PsA, which was ameliorated upon re-infusion of recombinant EDIL3 protein. The mitigation effect of EDIL3 on PsA depends on its regulation of the activation of monocyte-derived DCs (MoDCs) and T-help 17 cells (Th17). After inhibiting the function of MoDCs and Th17 cells with neutralizing antibodies, the beneficial effects of EDIL3 on PsA were lost. By inducing adenosine monophosphate (AMP)-activated protein kinase (AMPK) phosphorylation and suppressing protein kinase B (AKT) phosphorylation, EDIL3 attenuates intracellular glycolysis in MoDCs stimulated by glucose, thereby impeding their maturation and differentiation. Moreover, it diminishes the differentiation of Th17 cells and decelerates the progression of PsA. In conclusion, our findings elucidate the role and mechanism of EDIL3 in the development of PsA, providing a new target for clinical diagnosis and treatment.

IL-38 Aggravates Atopic Dermatitis via Facilitating Migration of Langerhans cells.

Atopic dermatitis (AD) is a common inflammation skin disease that involves dysregulated interplay between immune cells and keratinocytes. Interleukin-38 (IL-38), a poorly characterized IL-1 family cytokine, its role and mechanism in the pathogenesis of AD is elusive. Here, we show that IL-38 is mainly secreted by epidermal keratinocytes and highly expressed in the skin and downregulated in AD lesions. We generated IL-38 keratinocyte-specific knockout mice (K14Cre/+-IL-38f/f ) and induced AD models by 2,4-dinitrofluorobenzene (DNFB). Unexpectedly, after treatment with DNFB, K14Cre/+-IL-38f/f mice were less susceptible to cutaneous inflammation of AD. Moreover, keratinocyte-specific deletion of IL-38 suppressed the migration of Langerhans cells (LCs) into lymph nodes which results in disturbed differentiation of CD4+T cells and decreased the infiltration of immune cells into AD lesions. LCs are a type of dendritic cell that reside specifically in the epidermis and regulate immune responses. We developed LC-like cells in vitro from mouse bone marrow (BM) and treated with recombined IL-38. The results show that IL-38 depended on IL-36R, activated the phosphorylated expression of IRAK4 and NF-κB P65 and upregulated the expression of CCR7 to promoting the migration of LCs, nevertheless, the upregulation disappeared with the addition of IL-36 receptor antagonist (IL-36RA), IRAK4 or NF-κB P65 inhibitor. Furthermore, after treatment with IRAK4 inhibitors, the experimental AD phenotypes were alleviated and so IRAK4 is considered a promising target for the treatment of inflammatory diseases. Overall, our findings indicated a potential pathway that IL-38 depends on IL-36R, leading to LCs migration to promote AD by upregulating CCR7 via IRAK4/NF-κB and implied the prevention and treatment of AD, supporting potential clinical utilization of IRAK4 inhibitors in AD treatment.

Current and promising therapies based on the pathogenesis of Graves' ophthalmopathy.

Graves' ophthalmopathy (GO) is a hyperthyroidism-related and immune-mediated disease that poses a significant threat to human health. The pathogenesis of GO primarily involves T cells, B cells, and fibroblasts, suggesting a pivotal role for the thyrotropin-antibody-immunocyte-fibroblast axis. Traditional treatment approaches for Graves' disease (GD) or GO encompass antithyroid drugs (ATDs), radioactive iodine, and beta-blockers. However, despite decades of treatment, there has been limited improvement in the global incidence of GO. In recent years, promising therapies, including immunotherapy, have emerged as leading contenders, demonstrating substantial benefits in clinical trials by inhibiting the activation of immune cells like Th1 and B cells. Furthermore, the impact of diet, gut microbiota, and metabolites on GO regulation has been recognized, suggesting the potential of non-pharmaceutical interventions. Moreover, as traditional Chinese medicine (TCM) components have been extensively explored and have shown effective results in treating autoimmune diseases, remarkable progress has been achieved in managing GO with TCM. In this review, we elucidate the pathogenesis of GO, summarize current and prospective therapies for GO, and delve into the mechanisms and prospects of TCM in its treatment.

TRPC absence induces pro-inflammatory macrophages and gut microbe disorder, sensitizing mice to colitis.

The transient receptor potential canonical (TRPC) channels, encoded in seven non-allelic genes, are important contributors to calcium fluxes, are strongly associated with various diseases. Here we explored the consequences of ablating all seven TRPCs in mice focusing on colitis. We discovered that absence of all seven TRPC proteins in mice (TRPC HeptaKO mice) promotes the development of dextran sulfate sodium (DSS)-induced colitis. RNA-sequence analysis highlighted an extremely pro-inflammatory profile in colons of DSS-treated TRPC HeptaKO mice, with an amount of increased pro-inflammatory cytokines and chemokines. Flow cytometry analysis showed that the infiltration of Ly6Chi monocytes and neutrophils in colonic lamina propria was significantly increased in DSS-treated TRPC HeptaKO mice. Results also revealed that macrophages from TRPC HeptaKO mice exhibited M1 polarization and enhanced secretion of pro-inflammatory factors. In addition, the composition of gut microbiota was markedly disturbed in DSS-treated TRPC HeptaKO mice. However, upon antibiotic cocktail (Abx)-treatment, TRPC HeptaKO mice showed no significant differences with WT mice in disease severity. Collectively, these data suggest that ablation of all TRPCs promotes the development of DSS-induced colitis by inducing pro-inflammatory macrophages and gut microbiota disorder.

Beta-adrenergic receptor blocker propranolol triggers anti-tumor immunity and enhances irinotecan therapy in mice colorectal cancer.

Colorectal cancer (CRC) stands as the second leading cause of cancer-related deaths worldwide with limited available medicines. While drug repurposing comes as a promising strategy for cancer treatment, we discovered that propranolol (Prop), a non-selective ß1 and ß2 adrenergic receptor blocker, significantly inhibited the development of subcutaneous CT26 CRC and AOM/DSS-induced CRC models. The RNA-seq analysis highlighted the activated immune pathways after Prop treatment, with KEGG analysis enriched in T-cell differentiation. Routine analyses of blood revealed a decrease in neutrophil to lymphocyte ratio, a biomarker of systemic inflammation, and a prognostic indicator in the Prop-treated groups in both CRC models. Analysis of the tumor-infiltrating immune cells exhibited that Prop regressed the exhaustion of CD4+ and CD8+ T cells in the CT26-derived graft models, which was further corroborated in the AOM/DSS-induced models. Furthermore, bioinformatic analysis fitted well with the experimental data, showing that ß2 adrenergic receptor (ADRB2) was positively correlated with T-cell exhaustion signature in various tumors. The in vitro experiment showed no direct effect of Prop on CT26 cell viability, while T cells were activated with significantly-upregulated production of IFN-γ and Granzyme B. Consistently, Prop was unable to restrain CT26 tumor growth in nude mice. At last, the combination of Prop and the chemotherapeutic drug Irinotecan acted out the strongest inhibition in CT26 tumor progress. Collectively, we repurpose Prop as a promising and economical therapeutic drug for CRC treatment and highlight T-cell as its target.

Intestinal dysbiosis exacerbates the pathogenesis of psoriasis-like phenotype through changes in fatty acid metabolism.

The intestinal microbiota has been associated with host immunity as well as psoriasis; however, the mechanism of intestinal microbiota regulating psoriasis needs to be demonstrated systematically. Here, we sought to examine its role and mechanism of action in the pathogenesis of psoriasis. We found that the severity of psoriasis-like skin phenotype was accompanied by changes in the composition of the intestinal microbiota. We performed co-housing and fecal microbial transplantation (FMT) experiments using the K14-VEGF transgenic mouse model of psoriasis and demonstrated that the transfer of intestinal microbiota from mice with severe psoriasis-like skin phenotype exacerbated psoriasiform skin inflammation in mice with mild symptoms, including increasing the infiltration and differentiation of Th17, and increased the abundance of Prevotella, while decreasing that of Parabacteroides distasonis, in the colon. These alterations affected fatty acid metabolism, increasing the abundance of oleic and stearic acids. Meanwhile, gentamicin treatment significantly reduced the abundance of Prevotella and alleviated the psoriasis-like symptoms in both K14-VEGF mice and imiquimod (IMQ)-induced psoriasis-like mice. Indeed, administration of oleic and stearic acids exacerbated psoriasis-like symptoms and increased Th17 and monocyte-derived dendritic cell infiltration in the skin lesion areas in vivo, as well as increased the secretion of IL-23 by stimulating DCs in vitro. At last, we found that, treatment of PDE-4 inhibitor alleviated psoriasis-like phenotype of K14-VEGF mice accompanied by the recovery of intestinal microbiota, including the decrease of Prevotella and increase of Parabacteroides distasonis. Overall, our findings reveal that the intestinal microbiota modulates host metabolism and psoriasis-like skin inflammation in mice, suggesting a new target for the clinical diagnosis and treatment of psoriasis.

Interleukin-37 promotes DMBA/TPA skin cancer through SIGIRR-mediated inhibition of glycolysis in CD103+DC cells.

Interleukin 37 (IL-37), a member of the IL-1 family, is considered a suppressor of innate and adaptive immunity and, hence is a regulator of tumor immunity. However, the specific molecular mechanism and role of IL-37 in skin cancer remain unclear. Here, we report that IL-37b-transgenic mice (IL-37tg) treated with the carcinogenic 7,12-dimethylbenzoanthracene (DMBA)/12-o-tetradecylphorbol-13-acetate (TPA) exhibited enhanced skin cancer and increased tumor burden in the skin by inhibiting the function of CD103+ dendritic cells (DCs). Notably, IL-37 induced rapid phosphorylation of adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK), and via single immunoglobulin IL-1-related receptor (SIGIRR), inhibited the long-term Akt activation. Specifically, by affecting the SIGIRR-AMPK-Akt signaling axis, which is related to the regulation of glycolysis in CD103+DCs, IL-37 inhibited their anti-tumor function. Our results show that a marked correlation between the CD103+DC signature (IRF8, FMS-like tyrosine kinase 3 ligand, CLEC9A, CLNK, XCR1, BATF3, and ZBTB46) and chemokines C-X-C motif chemokine ligand 9, CXCL10, and CD8A in a mouse model with DMBA/TPA-induced skin cancer. In a word, our results highlight that IL-37 as an inhibitor of tumor immune surveillance through modulating CD103+DCs and establishing an important link between metabolism and immunity as a therapeutic target for skin cancer.

Gut Microbiota Dysbiosis and Altered Bile Acid Catabolism Lead to Metabolic Disorder in Psoriasis Mice.

Patients with psoriasis tend to have significant comorbidities, such as hyperlipemia, diabetes mellitus, and obesity, which belong to metabolic disorders. The specific mechanism through which psoriasis increases the metabolic disorder risk is uncertain. In this study, we demonstrated that the dysbiotic gut microbiota of 6-month-old psoriasis-like model mice (K14-VEGF-A-transgenic) exacerbated psoriasis disease and induced metabolic disorder when transferred into 2-month-old mice. By 16S rRNA gene sequencing, we confirmed that the Parabacteroides distasonis decreased with age in K14-VEGF mice, and P. distasonis also decreased in the transferred mice. Metabolomic screening identified an altered bile acid profile, including a decrease in chenodeoxycholic acid (CDCA) in the feces of transferred mice. Additionally, CDCA supplements prevented metabolic disorders in K14-VEGF-A-transgenic mice. Consequently, we found that aberrant bile acid metabolism may contribute to metabolic disorder in K14-VEGF-A-transgenic mice, indicating the possibility to prevent and treat the metabolic disorder in psoriasis mice by targeting gut microbial metabolites.

ACSL4 deficiency confers protection against ferroptosis-mediated acute kidney injury.

The term ferroptosis coined in 2012 causes acute kidney injury (AKI). However, its pathway mechanism in AKI is poorly understood. In this study, we conducted an RNA-sequence analysis of kidneys in AKI and normal mice to explore the pathway mechanism of ferroptosis. Consequently, differentially expressed genes highlighted Acyl-CoA synthetase long-chain family (ACSL4), a known promotor for ferroptosis. Besides, RT-PCR, Western blot, and immunohistochemical analyses confirmed its upregulation. HIF-1α was downregulated in I/R-AKI mice, and in vitro studies confirmed a negative regulation of HIF-1α on ACSL4. To explore the role of ACSL4 in AKI, we constructed ACSL4 knockout in kidney tubules of mice-as Cdh16Cre-ACSL4F/F mice. Results revealed that ACSL4 knockout significantly reduced ferroptosis and inhibited the functional and pathological injury of AKI mice. Meanwhile, the kidneys of Cdh16Cre-ACSL4F/F mice demonstrated a significantly decreased inflammation and macrophage infiltration. Further, additional explorations were explored to decipher a more thorough understanding of ferroptotic immunogenicity. As a result, neutrophils were not directly recruited by ferroptotic cells, but by ferroptotic cell-induced macrophages. Further, ACSL4 inhibitor rosiglitazone significantly inhibited AKI. Collectively, these data provide novel insights into the AKI pathogenesis, and defined ACSL4 as an effective target in AKI.

A role for whey acidic protein four-disulfide-core 12 (WFDC12) in the pathogenesis and development of psoriasis disease.

Whey acidic protein four-disulfide core domain protein 12 (WFDC12) has been implicated in the pathogenesis of psoriasis but the specific molecular mechanism is not clearly defined. In this study, we found the expression of WFDC12 protein closely correlated with psoriasis. WFDC12 in keratinocyte might increase infiltration of Langerhans cells (LCs) and monocyte-derived dendritic cells (moDDCs), up-regulating the co-stimulation molecular CD40/CD86. Th1 cells in lymph nodes were higher in K14-WFDC12 transgenic psoiasis-like mice. Meanwhile, the mRNA of IL-12 and IFN-γ in the lesion skin was significantly increased in transgenic mice. Moreover, we found that the expression of the proteins that participated in the retinoic acid-related pathway and immune signaling pathway was more changed in the lesion skin of K14-WFDC12 transgenic psoriasis-like mice. Collectively, the results implied that WFDC12 might affect the activation of the retinoic acid signaling pathway and regulate the infiltration of DC cells in the skin lesions and lymph nodes, thereby inducing Th1 cells differentiation and increasing the secretion of IFN-γ to exacerbate psoriasis in mice.

SerpinB7 deficiency contributes to development of psoriasis via calcium-mediated keratinocyte differentiation dysfunction.

Defective execution of proteases and protease inhibitors that mediate abnormal signaling cascades is emerging as a key contributor to skin diseases, such as psoriasis. SerpinB7 is identified as a skin-specific endogenous protease inhibitor, but the role and underlying mechanism in psoriasis are poorly understood. Here we found that SerpinB7 is highly expressed in psoriatic keratinocytes of patients and imiquimod-induced psoriatic lesions in mice. SerpinB7-/- mice showed abnormal epidermal barrier integrity and skin architecture in homeostasis, and aggravated psoriatic lesion with inhibiting terminal differentiation and increasing inflammatory cells infiltration compared to SerpinB7+/+ mice after Imiquimod treatment. Mechanistically, SerpinB7 deficiency results in excessive proliferation and impaired differentiation, as well as increased chemokines and antimicrobial peptide expression in normal human epidermal keratinocyte and mouse primary keratinocyte. Transcriptomics and proteomics results showed that the SeprinB7 deficiency affected keratinocyte differentiation and proinflammatory cytokines, possibly by affecting the calcium ion channel-related proteins. Notably, we demonstrated that SerpinB7 deficiency prevented the increase in intracellular Ca2+ influx, which was partly eliminated by the intracellular Ca2+ chelator BAPTA-AM. Our findings first described the critical role of SerpinB7 in the regulation of keratinocyte differentiation and psoriatic microenvironment mediated via keratinocytes' intracellular calcium flux, proposing a new candidate for therapeutic targets in psoriasis.

Interleukin-37 promotes colitis-associated carcinogenesis via SIGIRR-mediated cytotoxic T cells dysfunction.

Interleukin-37b (hereafter called IL-37) was identified as fundamental inhibitor of natural and acquired immunity. The molecular mechanism and function of IL-37 in colorectal cancer (CRC) has been elusive. Here, we found that IL-37 transgenic (IL-37tg) mice were highly susceptible to colitis-associated colorectal cancer (CAC) and suffered from dramatically increased tumor burdens in colon. Nevertheless, IL-37 is dispensable for intestinal mutagenesis, and CRC cell proliferation, apoptosis, and migration. Notably, IL-37 dampened protective cytotoxic T cell-mediated immunity in CAC and B16-OVA models. CD8+ T cell dysfunction is defined by reduced retention and activation as well as failure to proliferate and produce cytotoxic cytokines in IL-37tg mice, enabling tumor evasion of immune surveillance. The dysfunction led by IL-37 antagonizes IL-18-induced proliferation and effector function of CD8+ T cells, which was dependent on SIGIRR (single immunoglobulin interleukin-1 receptor-related protein). Finally, we observed that IL-37 levels were significantly increased in CRC patients, and positively correlated with serum CRC biomarker CEA levels, but negatively correlated with the CD8+ T cell infiltration in CRC patients. Our findings highlight the role of IL-37 in harnessing antitumor immunity by inactivation of cytotoxic T cells and establish a new defined inhibitory factor IL-37/SIGIRR in cancer-immunity cycle as therapeutic targets in CRC.

Metabolic Syndrome and Psoriasis: Mechanisms and Future Directions.

Psoriasis is an immune-mediated systemic disease with associated comorbidities, including metabolic syndrome (MetS) which contributes substantially to premature mortality in patients with psoriasis. However, the pathological mechanisms underlying this comorbidity are unclear. Studies have shown that the pathological parameters of psoriasis mediate the development of MetS. We reviewed the potential mechanisms which mediate the association between psoriasis and MetS, including endoplasmic reticulum stress, pro-inflammatory cytokine releases, excess production of reactive oxygen species, alterations in adipocytokine levels and gut microbiota dysbiosis. Here, we highlight important research questions regarding this association and offer insights into MetS research and treatment.