Iron plays a critical role in immune responses. However, its role in T helper cell differentiation and function remains poorly understood. In this study, it is shown that the restraint of iron availability through blocking CD71-mediated iron endocytosis impaired the differentiation and pathogenicity of T_H 17 cells. Administrations of anti-CD71 mAb could relieve the development of experimental autoimmune encephalomyelitis (EAE). Mechanistically, the iron deficiency due to the blocking of CD71 enhanced IL-2 expression, which further restrained the differentiation of T_H 17 cells. Meanwhile, CD71 blockade impaired histone modifications of Il17 gene and reduced the recruitment of RORγt to Il17a locus. In sum, the findings reveal that iron plays a pivotal role in regulating T_H 17 cell differentiation and function in autoimmune diseases.

Keywords: IL-2; TH17 cells; anti-CD71 mAb; autoimmune diseases; histone modifications; iron.

Elderly patients are prone to cognitive impairment and memory loss after surgical operations. This perioperative cerebral damage, named postoperative cognitive dysfunction (POCD), is profoundly affected by anesthesia. N6-methyladenosine (m6A) RNA methylation is a widely-studied epigenetic modification to regulate gene expression; however, is has never been studied in POCD. In the present study, elderly POCD mouse models were constructed using sevoflurane, and we observed a compromised global m6A RNA methylation in the mice's hippocampuses compared with the control. Our RIP-Seq data suggested that 1244 genes (SOX2, SYN1, and BDNF) showed m6A RNA methylation in their 5'UTRs, which was significantly lower than that in the control; while only 56 genes (BACE1 and IL17A) showed m6A RNA methylation in their 5'UTRs, which was significantly higher than that in the control. Unexpectedly, m6A RNA methylation with significant differences in exons, introns, or 3'UTRs was observed in only few genes. Although we failed to find any differences in the expression of m6A-associated proteins, such as m6A "writers", "erasers", and "readers", between the sevoflurane treatment and control groups, RIP-qPCR assays indicated that the binding affinity of METTL3 on mRNA 5'UTRs was particularly weakened in target genes by sevoflurane. Finally, we found that phosphorylation of METTL3 could be reduced by sevoflurane because of the inactivation of the MAPK/ERK pathway. Overall, our study determined that the inactivation of METTL3 in the mouse hippocampus, induced by sevoflurane-mediated MAPK/ERK suppression in vivo, resulted in a perturbation in m6A RNA methylation signals in the pathogenesis of POCD.

Keywords: METTL3; POCD; hippocampus; m6A methylation; sevoflurane.

Background: Coronavirus disease 2019 is characterized by the elevation of a broad spectrum of inflammatory mediators associated with poor disease outcomes. We aimed at an in-silico analysis of regulatory microRNA and their transcription factors (TF) for these inflammatory genes that may help to devise potential therapeutic strategies in the future.

Methods: The cytokine regulating immune-expressed genes (CRIEG) were sorted from literature and the GEO microarray dataset. Their co-differentially expressed miRNA and transcription factors were predicted from publicly available databases. Enrichment analysis was done through mienturnet, MiEAA, Gene Ontology, and pathways predicted by KEGG and Reactome pathways. Finally, the functional and regulatory features were analyzed and visualized through Cytoscape.

Results: Sixteen CRIEG were observed to have a significant protein-protein interaction network. The ontological analysis revealed significantly enriched pathways for biological processes, molecular functions, and cellular components. The search performed in the miRNA database yielded ten miRNAs that are significantly involved in regulating these genes and their transcription factors.

Conclusion: An in-silico representation of a network involving miRNAs, CRIEGs, and TF, which take part in the inflammatory response in COVID-19, has been elucidated. Thus, these regulatory factors may have potentially critical roles in the inflammatory response in COVID-19 and may be explored further to develop targeted therapeutic strategies and mechanistic validation.

Keywords: AHR, Aryl hydrocarbon receptor; ARDS, acute respiratory distress syndrome; BAL, Bronchoalveolar Lavage; CC, Cellular components; CCL, Chemokine (C-C motif) ligands; CCL2, C-C motif chemokine 2; CCL3, C-C motif chemokine 3; CCL4, C-C motif chemokine 4; CCR, CC chemokine receptor; CEBPA, CCAAT/enhancer-binding protein alpha; COVID-19; COVID-19, Coronavirus Disease 2019; CREM, cAMP responsive element modulator; CRIEGs, Cytokine regulating immune expressed genes; CSF2, Granulocyte-macrophage colony-stimulating factor; CSF3, Granulocyte colony-stimulating factor; CXCL10, C-X-C motif chemokine 10; CXCL2, Chemokine (C-X-C motif) ligand 2; CXCL8, Interleukin-8; CXCR, C-X-C chemokine receptor; Cytokine storm; Cytokines; DDIT3, DNA damage-inducible transcript 3 protein; DEGs, Differentially expressed genes; E2F1, Transcription factor E2F1; EGR1, Early growth response protein 1; EP300, Histone acetyltransferase p300; ESR1, Estrogen receptor, Nuclear hormone receptor; ETS2, Protein C-ets-2; FOXP3, Forkhead box protein P3; GO, Gene Ontology; GSEs, Gene Series Expressions; HDAC1, Histone deacetylase 1; HDAC2, Histone deacetylase 2; HSF1, Heat shock factor protein 1; IL-6, interleukin-6; IL10, Interleukin-10; IL17A, Interleukin-17A; IL1B, Interleukin-1; IL2, Interleukin-2; IL6, Interleukin-6; IL7, Interleukin-7; IL9, Interleukin-9; IP-10, Interferon-Inducible Protein 10; IRF1, Interferon regulatory factor 1; Immuno-interactomics; JAK-STAT, Janus kinase (JAK)-signal transducer and activator; JAK2, Tyrosine-protein kinase JAK2; JUN, Transcription factor AP-1; KEGG, Kyoto Encyclopedia of Genes and Genomes; KLF4, Krueppel-like factor 4; MicroRNA, SARS-CoV-2; NF-κB, nuclear factor kappa-light-chain-enhancer of activated B cells; NFAT5, Nuclear factor of activated T-cells 5; NFKB1, Nuclear factor NF-kappa-B p105 subunit; NFKBIA, NF-kappa-B inhibitor alpha; NR1I2, Nuclear receptor subfamily 1 group I member 2; PDM, peripheral blood mononuclear cell; REL, Proto-oncogene c-Rel; RELA, Transcription factor p65; RUNX1, Runt-related transcription factor 1; SARS-CoV-2, Severe Acute Respiratory Syndrome Coronavirus 2; SIRT1, NAD-dependent protein deacetylase sirtuin-1; SP1, Transcription factor Sp1; SPI1, Transcription factor PU.1; STAT1, Signal transducer and activator of transcription 1-alpha/beta; STAT3, Signal transducer and activator of transcription 3; TLR3, Toll-like receptor 3 (TLR3); TNF, Tumor necrosis factor; TNF-α, Tumor Necrosis Factor-Alpha; VDR, Vitamin D3 receptor; XBP1, X-box-binding protein 1; ZFP36, mRNA decay activator protein ZFP36; ZNF300, Zinc finger protein 300, heme oxygenase-1 (HO-1); miEAA, miRNA Enrichment Analysis and Annotation t.

Angiogenesis is an essential physiological process and hallmark of cancer. Currently, antiangiogenic therapy, mostly targeting the vascular endothelial growth factor (VEGF)/VEGFR2 signaling axis, is commonly used in the clinic for solid tumors. However, antiangiogenic therapies for breast cancer patients have produced limited survival benefits since cancer cells rapidly resistant to anti-VEGFR2 therapy. We applied the low-dose and high-dose VEGFR2 mAb or VEGFR2-tyrosine kinase inhibitor (TKI) agents in multiple breast cancer mouse models and found that low-dose VEGFR2 mAb or VEGFR2-TKI achieved good effects in controlling cancer progression, while high-dose treatment was not effective. To further investigate the mechanism involved in regulating the drug resistance, we found that high-dose anti-VEGFR2 treatment elicited IL17A expression in γδ T cells via VEGFR1-PI3K-AKT pathway activation and then promoted N2-like neutrophil polarization, thus inducing CD8⁺ T cell exhaustion to shape an immunosuppressive microenvironment. Combining anti-VEGFR2 therapy with immunotherapy such as IL17A, PD-1 or Ly-6G mAb therapy, which targeting the immunomodulatory axis of "γδT17 cells-N2 neutrophils" in vivo, showed promising therapeutic effects in breast cancer treatment. This study illustrates the potential mechanism of antiangiogenic therapy resistance in breast cancer and provides synergy treatment for cancer.

Keywords: IL17A; anti-VEGFR2 therapy; breast cancer; neutrophil; therapy resistance; γδT cell.

The pathogenic hyper-inflammatory response has been revealed as the major cause of the severity and death of the Corona Virus Disease 2019 (COVID-19). Xuanfei Baidu Decoction (XFBD) as one of the "three medicines and three prescriptions" for the clinically effective treatment of COVID-19 in China, shows unique advantages in the control of symptomatic transition from moderate to severe disease states. However, the roles of XFBD to against hyper-inflammatory response and its mechanism remain unclear. Here, we established acute lung injury (ALI) model induced by lipopolysaccharide (LPS), presenting a hyperinflammatory process to explore the pharmacodynamic effect and molecular mechanism of XFBD on ALI. The in vitro experiments demonstrated that XFBD inhibited the secretion of IL-6 and TNF-α and iNOS activity in LPS-stimulated RAW264.7 macrophages. In vivo, we confirmed that XFBD improved pulmonary injury via down-regulating the expression of proinflammatory cytokines such as IL-6, TNF-α and IL1-β as well as macrophages and neutrophils infiltration in LPS-induced ALI mice. Mechanically, we revealed that XFBD treated LPS-induced acute lung injury through PD-1/IL17A pathway which regulates the infiltration of neutrophils and macrophages. Additionally, one major compound from XFBD, i.e. glycyrrhizic acid, shows a high binding affinity with IL17A. In conclusion, we demonstrated the therapeutic effects of XFBD, which provides the immune foundations of XFBD and fatherly support its clinical applications.

Keywords: Acteoside (PubChem CID: 5281800); Acute lung injury; Amygdalin (PubChem CID: 656516); COVID-19; Ephedrine (PubChem CID: 9294); Glycyrrhizic acid (PubChem CID: 14982); Hastatoside (PubChem CID: 92043450); Liquiritin (PubChem CID: 503737); Naringin (PubChem CID: 442428); PD-1/IL17A pathway; Polydatin (PubChem CID: 5281718); Sinapine (PubChem CID: 5280385); Systematic network pharmacological analysis; Verbenalin (PubChem CID: 73467); Xuanfei Baidu Decoction.

Itch is one of the major clinical manifestations of psoriasis, which is closely related with neurogenic inflammation and difficult to control. Colquhounia Root (CR) is a Chinese herb exhibiting broad bioactivities on anti-inflammation. This study was designed to explore the antipsoriatic and anti-itch potential of CR and its underlying mechanisms. Mice in a model of imiquimod-induced psoriasiform dermatitis were treated topically with CR for 7 days, and the severity of skin lesions and itch was significantly ameliorated. CR reduced the inflammatory cell infiltration, as well as mast cells in skins. Particularly, the expression of inflammatory cytokines and chemokine including Il17a, Il22, and Ccl20 and itch-related molecules such as SP, CGRP, and NGF in lesions were decreased in diseased mice upon application with CR. The normal human epidermal keratinocytes were stimulated with the M5 cytokine cocktail, the mixture of IL-17A, IL-22, Oncostatin M, IL-1α, and TNF-α, and cell viability and mRNA expression levels of inflammatory factors and itch-related molecules were measured after being treated with CR. We found that CR inhibited both cell hyperproliferation and overexpression of inflammatory cytokines and itch-related molecules in vitro. Altogether, we conclude that CR relieves psoriatic lesions and itch via controlling immunological and neurogenic inflammation.

Mesenchymal stem cells (MSCs) immunomodulate inflammatory responses through paracrine signalling, including via secretion of extracellular vesicles (EVs) in the cell secretome. We evaluated the therapeutic potential of MSCs-derived small EVs in an antigen-induced model of arthritis (AIA). EVs isolated from MSCs cultured normoxically (21% O₂, 5% CO₂), hypoxically (2% O₂, 5% CO₂) or with a pro-inflammatory cytokine cocktail were applied into the AIA model. Disease pathology was assessed post-arthritis induction through swelling and histopathological analysis of synovial joint structure. Activated CD4+ T cells from healthy mice were cultured with EVs or MSCs to assess deactivation capabilities prior to application of standard EVs in vivo to assess T cell polarisation within the immune response to AIA. All EVs treatments reduced knee-joint swelling whilst only normoxic and pro-inflammatory primed EVs improved histopathological outcomes. In vitro culture with EVs did not achieve T cell deactivation. Polarisation towards CD4+ helper cells expressing IL17a (Th17) was reduced when normoxic and hypoxic EV treatments were applied in vitro. Normoxic EVs applied into the AIA model reduced Th17 polarisation and improved Regulatory T cell (Treg):Th17 homeostatic balance. Normoxic EVs present the optimal strategy for broad therapeutic benefit. EVs present an effective novel technology with the potential for cell-free therapeutic translation.

Keywords: extracellular vesicles; immunomodulation; inflammation; mesenchymal stem cells; rheumatoid arthritis.

Vitiligo is an autoimmune skin disorder defined by the destruction of functional epidermal melanocytes. It is a multifactorial and polygenic disorder caused due to oxidative stress, endoplasmic reticulum (ER) stress, and autoimmunity, among other factors. In the present study, we aimed to investigate the association of X-box Binding Protein 1 (XBP1) and Interleukin-17A (IL-17A) polymorphisms and monitor their systemic as well as skin expression levels in vitiligo patients from Gujarat population in India. XBP1 rs2269577 G/C, IL17A rs2275913 G/A and IL17A rs8193036 C/T polymorphisms were genotyped by Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) method in 312 controls and 276 vitiligo patients. Transcript levels of spliced (sXBP1), unspliced XBP1 (uXBP1) and IL17A from peripheral blood mononuclear cells (PBMCs) as well as spliced and unspliced XBP1 from skin samples were analyzed by qPCR. IL-17A protein levels in suction-induced blister fluid (SBF) from the skin of study subjects were estimated by ELISA. The results revealed that genotype (p=0.010) and allele (p=0.014) frequencies of XBP1 rs2269577 G/C polymorphism were significantly different, however, no significant difference was observed in frequencies of IL17A rs2275913 G/A and IL17A rs8193036 C/T polymorphisms in control and patient population. Gene expression analysis revealed that sXBP1 and IL17A levels were significantly higher in PBMCs of generalized (p=0.030 and p=0.039, respectively) and active (p=0.024 and p=0.017, respectively) vitiligo patients. Moreover, we observed a significantly elevated sXBP1 expression (p=0.037) as well as IL-17A protein levels (p=0.009) in perilesional skin of vitiligo patients as compared to controls. Overall, these findings suggest XBP1 and IL17A play an important role in vitiligo and further substantiate the involvement of ER stress in exacerbating immune-mediated vitiligo pathogenesis.

Keywords: autoimmunity; cytokines; endoplasmic reticulum stress (ER stress); genetic polymorphisms and disease association; interleukin; vitiligo.

Streptococcus suis (S. suis) is an emerging zoonotic agent that can cause meningitis in humans with high mortality and morbidity. Meningitic S. suis can induce higher level of IL-17 than non-meningitic S. suis. Besides, IL-17A plays various roles on bacterial clearance or disruption of blood-CNS barriers through the downregulation and reorganization of tight junction (TJ) molecules. However, it remains to be elucidated for the role of IL-17A on the infection with meningitic S. suis. Here, we found that meningitic S. suis infection could not only cause acute death due to the damage of multiple organs, but also cause meningitis and clinical nervous signs since 60 h of post-infection due to the penetration of blood-CNS barriers after lasting bacteremia. In contrast, the mice with deficiency of il17a gene could not significantly change the acute inflammatory response and acute death, but it could not show obvious meningitis and clinical nervous signs caused by the meningitic S. suis infection. In addition, we also found that IL-17A could inhibit the transcription and expression of TJ proteins that facilitated the leakage of blood-CNS barriers since 60 h of post-infection during meningitic S. suis infection. Thus, our findings demonstrated that IL-17A could downregulate TJ proteins, which undoubtedly facilitated the leakage of blood-CNS barriers for bacterial invasion and then caused S. suis meningitis, providing potential targets for future prevention and treatment of this disease.

Keywords: Blood-CNS barriers; Interleukin-17A; Meningitis; Streptococcus suis; Tight junction proteins.

Background: Peripheral spondyloarthritis is a chronic inflammatory disease in which clinical presentation is related to the presence of arthritis, enthesitis and/or dactylitis. This term is used interchangeably with some of its subtypes such as psoriatic arthritis, reactive arthritis, and undifferentiated spondyloarthritis.

Objective: To develop and formulate a set of specific recommendations based on the best available evidence for the diagnosis, treatment and monitoring of adult patients with peripheral spondyloarthritis.

Methods: A working group was established, clinical questions were formulated, outcomes were graded, and a systematic search for evidence was conducted. The guideline panel was multidisciplinary (including patient representatives) and balanced. Following the formal expert consensus method, the GRADE methodology "Grading of Recommendations Assessment, Development and Evaluation" was used to assess the quality of the evidence and generate the recommendations. The Clinical Practice Guideline includes ten recommendations; related to monitoring of disease activity (n = 1) and treatment (n = 9).

Results: In patients with peripheral spondyloarthritis, the use of methotrexate or sulfasalazine as the first line of treatment is suggested, and local injections of glucocorticoids is recommended conditionally. In patients with failure to cDMARDs, an anti TNFα or an anti IL17A is recommended. In case of failure to bDMARDs, it is suggested to use another bDMARD or JAK inhibitor. In patients with peripheral spondyloarthritis associated to inflammatory bowel disease, it is recommended to start treatment with cDMARDs; in the absence of response, the use of an anti TNFα over an anti-IL-17 or an anti-IL-12-23 is recommended as a second line of treatment. In patients with psoriatic arthritis, the combined use of methotrexate with bDMARD is conditionally recommended for optimization of dosing. To assess disease activity in Psoriatic Arthritis, the use of DAPSA or MDA is suggested for patient monitoring.

Conclusions: This set of recommendations provides an updated guide on the diagnosis and treatment of peripheral spondyloarthritis.

Keywords: Clinical practice guideline; Espondiloartritis; Guía de práctica clínica; Monitoring; Seguimiento; Spondyloarthritis; Tratamiento; Treatment.

An intact and fully functional immune system plays a crucial role in the prevention of several infectious diseases. Interleukin (IL)17 is significantly involved in oral mucosa immunity against several antigens and microorganisms, including Candida albicans (CA). Herein, we present three cases of oral candidiasis (OC) related to the use of an IL17A inhibitor for psoriasis. Three psoriatic individuals presented for evaluation of widespread symptomatic oral lesions temporally correlated with the onset of IL17A inhibitors (secukinumab in two patients and brodalumab in one patient). Clinical examination revealed either partially removable white plaques in an erythematous background (case #1) or diffuse erythematous lesions (cases #2 and 3) involving several areas of the oral mucosa. Cytology smear, accompanied by histopathologic examination in case #1, confirmed the clinical impression of OC in all three cases. All patients received antifungal therapy with satisfactory clinical response. No discontinuation of the antipsoriatic regimen was recommended, but all patients were advised to remain under monitoring for possible OC relapses. During the last few years, new systemic biologic agents targeting IL17 have been used for the management of variable immune-mediated diseases. Few clinical trials and scarce case reports have shown that these medications place individuals at high risk of developing candidiasis. We propose that patients treated with these medications should be at close monitoring for the development of OC and, if it occurs, receive appropriate management.

Keywords: brodalumab; inhibitor; interleukin 17; oral candidiasis; psoriasis; secukinumab; type 17 immunity.

Background and aims: Ileocolonic resection is frequently needed in the course of Crohn's disease (CD) and post-operative recurrence is extremely common. Our main objective was to analyze gene expression in the mucosa of CD patients at time of surgery and post-operative endoscopy, in order to identify predictors and mechanisms of early endoscopic recurrence.

Methods: We conducted transcriptome analyses on ileal mucosa samples collected from inflamed sections of the surgical specimens (n=200), from ileal resection margins (n=149) and in the neo-terminal ileum 6 months after surgery (n=122); with non-IBD controls (n=25). The primary endpoint was post-operative endoscopic recurrence at month 6. We applied regression models to identify gene signatures predicting endoscopic recurrence.

Results: Chronic inflammation was associated with strong expression of inflammatory genes (IL-6, IL-8, IL-1B) and decreased expression of genes involved in metabolic processes, but with a high inter-individual heterogeneity. Gene signatures associated with early endoscopic recurrence was mainly characterized by upregulation of TNFα, IFNγ, IL23A, and IL17A. Pathway analyses showed that upregulation of mitochondrial dysfunction within the inflammation and the JAK/STAT at the ileal margin were predictive of post-operative recurrence. A combined model integrating these top pathway signatures improved the prediction of endoscopic recurrence (AUC of 0.79). STAT3 phosphorylation at the surgical ileal margin was associated with severe recurrence at six months.

Conclusion: We identify several biological pathways in the surgical specimen associated with an increased risk of disease recurrence. Integration of JAK/STAT and mitochondrial dysfunction pathways in the clinical model improved the prediction of post-operative recurrence.

Clec1A, a member of C-type lectin receptor family, has a carbohydrate recognition domain in its extracellular region, but no known signaling motif in the cytoplasmic domain. Clec1a is highly expressed in endothelial cells and weakly in dendritic cells. Although this molecule was reported to play an important role in the host defense against Aspergillus fumigatus by recognizing 1,8-dihydroxynaphthalene-melanin on the fungal surface, the roles of this molecule in un-infected animals remain to be elucidated. In this study, we found that Clec1a^-/-mice develop milder symptoms upon induction of experimental autoimmune encephalomyelitis (EAE), an animal model for multiple sclerosis. The maximum disease score was significantly lower, and demyelination and inflammation of the spinal cord were much milder in Clec1a^-/- mice compared to wild-type mice. No abnormality was detected in the immune cell composition in the draining lymph nodes and spleen on day 10 and 16 after EAE induction. Recall memory T cell proliferation after restimulation with myelin oligodendrocyte glycoprotein peptide (MOG_35-55) in vitro was decreased in Clec1a^-/- mice, and antigen presenting ability of Clec1a^-/- dendritic cells was impaired. Interestingly, RNA-Seq and RT-qPCR analyses clearly showed that the expression of inflammatory cytokines including Il17a, Il6 and Il1b was greatly decreased in Clec1a^-/-mice after induction of EAE, suggesting that this reduced cytokine production is responsible for the amelioration of EAE in Clec1a^-/-mice. These observations suggest a novel function of Clec1A in the immune system.

Keywords: C-type lectin receptor; Clec1a; IL-17; experimental autoimmune encephalomyelitis.

Objective: The aim of this study was to systematically update the evidence for associations between host genetic variants and subgingival microbial detection and counts.

Materials and methods: Following a previous systematic review (Nibali et al. J Clin Periodontol 43(11): 889-900, 15), an update of a systematic search of the literature was conducted in Ovid Medline, Embase, LILACS, and Cochrane Library for studies reporting data on host genetic variants and detection of microbes subgingivally published in the last 6 years.

Results: A total of 19 studies were included in the review, from an initial search of 2797 titles. Studies consisted mainly of candidate gene studies and of one genome-wide analysis. A total of 62 studies were considered for summary findings, including 43 identified in the previous systematic review of studies published up to 2015. Meta-analyses were done when appropriate including both papers in the original review and in the update. Meta-analyses revealed lack of associations between IL1 composite genotype and subgingival detection of Aggregatibacter acinomycetemcomitans, Poprhyromonas gingivalis, Tannerella forsythia, Treponema denticola, and Prevotella intermedia. Promising evidence is emerging from other genetic variants and from sub-analyses of data from genome-association studies. Among other studies with candidate-gene, target SNPs were mainly within the IL10, IL6, IL4, IL8, IL17A, and VDR gene.

Conclusions: IL1 composite genotype does not seem to be associated with subgingival microbial detection. Promising associations should be pursued by future studies, including studies employing -OMICS technologies.

Clinical relevance: A better knowledge of which host genetic variant predispose to subgingival microbial colonization and to the development of progression of periodontal disease could potentially help to better understand periodontal disease pathogenesis and help with its management.

Keywords: Bacteria; Genetic; Infectogenomics; Periodontitis.