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Pro-inflammatory cytokines are emerging as neuroinflammatory mediators in Parkinson's disease (PD) due to their ability to act through neuronal cytokine receptors. Critical questions persist regarding the role of cytokines in neuronal dysfunction and their contribution to PD pathology. Specifically, the potential synergy of the hallmark PD protein alpha-synuclein (α-syn) with cytokines is of interest. We therefore investigated the direct impact of pro-inflammatory cytokines on neurons and hypothesized that α-syn pathology exacerbates cytokine-induced neuronal deficits in PD. iPSC-derived cortical neurons (CNs) from healthy controls and patients with α-syn gene locus duplication (SNCA dupl) were stimulated with IL-17A, TNF-α, IFN-γ, or a combination thereof. For rescue experiments, CNs were pre-treated with α-syn anti-oligomerisation compound NPT100-18A prior to IL-17A stimulation. Cytokine receptor expression, microtubule cytoskeleton, axonal transport and neuronal activity were assessed. SNCA dupl CNs displayed an increased IL-17A receptor expression and impaired IL-17A-mediated cytokine receptor regulation. Cytokines exacerbated the altered distribution of tubulin post-translational modifications in SNCA dupl neurites, with SNCA dupl-specific IL-17A effects. Tau pathology in SNCA dupl CNs was also aggravated by IL-17A and cytokine mix. Cytokines slowed down mitochondrial axonal transport, with IL-17A-mediated retrograde slowing in SNCA dupl only. The pre-treatment of SNCA dupl CNs with NPT100-18A prevented the IL-17A-induced functional impairments in axonal transport and neural activity. Our work elucidates the detrimental effects of pro-inflammatory cytokines, particularly IL-17A, on human neuronal structure and function in the context of α-syn pathology, suggesting that cytokine-mediated inflammation represents a second hit to neurons in PD which is amenable to disease modifying therapies that are currently in clinical trials., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

In response to pro-inflammatory cytokines such as interleukin (IL)-1β, dental pulp fibroblasts produce various inflammatory mediators, including IL-6, IL-8, CC chemokine ligand 20 (CCL20), and CXC chemokine ligand 10 (CXCL10), leading to the progression of pulpitis. IL-17/IL-17A (IL-17A) is a pro-inflammatory cytokine secreted by T helper (Th) 17 cells following their recruitment to inflamed sites; however, the roles of IL-17A during pulpitis remain unclear. The purpose of this study was to investigate the effect of IL-17A on IL-6, IL-8, CCL20 and CXCL10 production by human dental pulp fibroblasts (HDPFs) in vitro. IL-17A at a concentration of 100 ng/ml induced the production of 10 times more IL-8 and 4 times more CXCL10, but not IL-6 and CCL20, compared to controls. Co-stimulation of HDPFs with IL-17A and IL-1β synergistically enhanced the production of IL-6, CCL20, IL-8 and CXCL10. IL-1β increased expression of IL-17 receptor/IL-17RA (IL-17R) on HDPFs. Moreover, the cell signal pathways of p38 mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) were more potently activated by simultaneous stimulation with IL-17A and IL-1β. These findings suggest that IL-17A participates in the progression of dental pulp inflammation through the enhanced production of inflammatory mediators in HDPFs., (© 2024 Scandinavian Division of the International Association for Dental Research. Published by John Wiley & Sons Ltd.)

IL-15 is a homeostatic cytokine for human T and NK cells. However, whether other cytokines influence the effect of IL-15 is not known. We studied the impact that IL-10, TGF-β, IL-17A, and IFN-γ have on the IL-15-induced proliferation of human T cells and the expression of HLA class I (HLA-I) molecules. Peripheral blood lymphocytes (PBLs) were labeled with CFSE and stimulated for 12 days with IL-15 in the absence or presence of the other cytokines. The proportion of proliferating T cells and the expression of cell surface HLA-I molecules were analyzed using flow cytometry. The IL-15-induced proliferation of T cells was paralleled by an increase in the expression of HC-10-reactive HLA-I molecules, namely on T cells that underwent ≥5-6 cycles of cell division. It is noteworthy that the IL-15-induced proliferation of T cells was potentiated by IL-10 and TGF-β but not by IL-17 or IFN-γ and was associated with a decrease in the expression of HC-10-reactive molecules. The cytokines IL-10 and TGF-β potentiate the proliferative capacity that IL-15 has on human T cells in vitro, an effect that is associated with a reduction in the amount of HC-10 reactive HLA class I molecules induced by IL-15.

Interleukin 17A (IL-17A) is a key cytokine promoting osteoblast formation, which contributes to osteogenesis. IL-17A functions in autophagy inhibition within osteoblasts. Metallothionein-2 (MT-2), as an important reactive oxygen species (ROS)-scavenging molecule, prevents oxidative stress from damaging osteoblast formation. The relationship between IL-17A-regulated autophagy and MT-2 production under oxidative stress deserves further exploration. In this study, we first investigated the roles of IL-17A in osteoblastic differentiation and ROS production in osteoblast precursors in the presence of hydrogen peroxide (H 2 O 2 ). Next, we explored the effects of IL-17A on autophagic activity and MT-2 protein expression in osteoblast precursors in the presence of H 2 O 2 . Ultimately, by using autophagic pharmacological agonist (rapamycin) and lentiviral transduction technology, the relationship between autophagy, IL-17A-regulated MT-2 protein expression and IL-17A-regulated ROS production was further elucidated. Our results showed that in the presence of H 2 O 2 , IL-17A promoted osteoblastic differentiation and inhibited ROS production. Moreover, in the presence of H 2 O 2 , IL-17A inhibited autophagic activity and promoted MT-2 protein expression in osteoblast precursors. Importantly, IL-17A-promoted MT-2 protein levels and -inhibited ROS production were reversed by autophagy activation with rapamycin. Furthermore, IL-17A-inhibited ROS production were blocked by MT-2 silencing. In conclusion, IL-17A promotes ROS clearance by inhibiting autophagic degradation of MT-2, thereby protecting osteoblast formation from oxidative stress.

Background: Xiao-Qing-Long-Tang (XQLT), a classical Chinese herbal medicine formula, has been extensively used for allergic asthma treatment. However, there is limited research on its anti-inflammatory effects and mechanisms specifically in neutrophilic asthma (NA)., Purpose: This study aims to investigate the potential therapeutic effects of XQLT against NA using a combination of network pharmacology and experimental validation., Study Design: By utilizing traditional Chinese medicine and disease databases, we constructed an XQLT-asthma network to identify potential targets of XQLT for NA. In the experimental phase, we utilized an ovalbumin (OVA)/lipopolysaccharide (LPS)-induced model for neutrophilic asthma and examined the therapeutic effects of XQLT., Results: Our research identified 174 bioactive components within XQLT and obtained 140 target genes of XQLT against asthma. Functional enrichment analysis revealed that these target genes were primarily associated with inflammation and cytokines. In the experimental validation, mice induced with OVA-LPS showcased eosinophilic and neutrophilic cell infiltration in peri-bronchial areas, elevated levels of IL-4 and IL-17 in both serum and lung, increased percentages of Th2 and Th17 cells in the spleen, as well as elevated levels of CD11b+ and CD103+ dendritic cells (DCs) within the lung. Treatment with XQLT effectively reduced IL-4 and IL-17 levels, decreased the percentages of Th2, Th17, CD11b+, and CD103+ DCs, and improved inflammatory cell infiltrations in lung tissues. These findings serve as a foundation for the potential clinical application of XQLT in neutrophilic asthma., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: The pathogenesis of primary sclerosing cholangitis (PSC) is unclear, although studies implicate IL-17A as an inflammatory mediator in this disease. However, a direct assessment of IL-17 signaling in PSC cholangiocytes is lacking. In this study, we aimed to investigate and characterize the response of PSC extrahepatic cholangiocyte organoids (ECO) to IL-17A stimulation., Methods: Cholangiocytes obtained from patients with PSC and without PSC by endoscopic retrograde cholangiography were cultured as ECO. The ECO were treated with vehicle or IL-17A and assessed by transcriptomics, secretome analysis, and genome sequencing., Results: Unsupervised clustering of all integrated single-cell RNA sequencing data identified 8 cholangiocyte clusters that did not differ between PSC and non-PSC ECO. However, PSC ECO cells demonstrated a robust response to IL-17 treatment, as noted by an increased number of differentially expressed genes by transcriptomics and more abundant chemokine and cytokine expression and secretion. After rigorous filtering, genome sequencing identified candidate somatic variants shared among PSC ECO from unrelated individuals. However, no candidate rare variants in genes regulating the IL-17 pathway were identified, but rare variants regulating the MAPK signaling pathway were present in all PSC ECO., Conclusions: PSC and non-PSC patient-derived ECO respond differently to IL-17 stimulation, implicating this pathway in the pathogenesis of PSC., (Copyright © 2024 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Association for the Study of Liver Diseases.)

Objective: To explore the role of interleukin (IL)-17 in connective tissue disease-associated pulmonary arterial hypertension (CTD-PAH) and to investigate its possible mechanism on pulmonary artery smooth muscle cells (PASMCs)., Methods: Enzyme-linked immunosorbent assay (ELISA) were used to compare levels of serum IL-17 in patients with CTD-PAH and healthy controls (HCs). After treatment for 3 months, the serum IL-17 levels were tested in CTD-PAH. ELISA and immunohistochemistry were used to compare levels of serum IL-17 and numbers of pulmonary artery IL-17 + cells, respectively, in a rat model of monocrotaline-induced PAH and untreated rats. Proliferation, migration, and inflammatory factors expression of PASMCs were assessed after stimulation with different concentrations of IL-17 for various time periods. Proteins in the mitogen-activated protein kinase (MAPK) pathway were examined by western blot., Results: Levels of IL-17 were upregulated in patients with CTD-PAH compared to HCs. After 3 months of treatment, serum IL-17 levels were downregulated with pulmonary artery pressure amelioration. Moreover, serum IL-17 levels and numbers of IL-17 + cells infiltrating lung arterioles were increased in PAH model rats. IL-17 could dose- and time-dependently promote proliferation and migration of PASMCs as well as time-dependently induce IL-6 and intercellular cell adhesion molecule-1 (ICAM-1) expression. The levels of MKK6 increased after IL-17 treatment. Inhibition of MAPK decreased proliferation of PASMCs., Conclusion: Levels of IL-17 may increase in CTD-PAH, and IL-17 promotes proliferation, migration, and secretion of IL-6 and ICAM in PASMCs, respectively, which likely involves the p-38 MAPK pathway., (© 2024 The Authors. Immunity, Inflammation and Disease published by John Wiley & Sons Ltd.)

Background: Neuroinflammation induced by systemic inflammation is a risk factor for developing chronic neurologic disorders. Oleuropein (OLE) has antioxidant and anti-inflammatory properties; however, its effect on systemic inflammation-related neuroinflammation is unknown., Objectives: This study aimed to determine whether OLE protects against systemic lipopolysaccharide (LPS)-induced neuroinflammation in rats., Methods: Six-wk-old Wistar rats were randomly assigned to 1 of the following 5 groups: 1) control, 2) OLE-only, 3) LPS + vehicle, 4) OLE+LPS (O-LPS), and 5) a single-dose OLE + LPS (SO-LPS group). OLE 200 mg/kg or saline as a vehicle was administered via gavage for 7 d. On the seventh day, 2.5 mg/kg LPS was intraperitoneally administered. The rats were decapitated after 24 h of LPS treatment, and serum collection and tissue dissection were performed. The study assessed astrocyte and microglial activation using glial fibrillary acidic protein (GFAP) and CD11b immunohistochemistry, nod-like receptor protein-3, interleukin (IL)-1β, IL-17A, and IL-4 concentrations in prefrontal and hippocampal tissues via enzyme-linked immunosorbent assay, and total antioxidant/oxidant status (TAS/TOS) in serum and tissues via spectrophotometry., Results: In both the O-LPS and SO-LPS groups, LPS-related activation of microglia and astrocytes was suppressed in the cortex and hippocampus (P < 0.001), excluding cortical astrocyte activation, which was suppressed only in the SO-LPS group (P < 0.001). Hippocampal GFAP immunoreactivity and IL-17A concentrations in the dentate gyrus were higher in the OLE group than those in the control group, but LPS-related increases in these concentrations were suppressed in the O-LPS group. The O-LPS group had higher cortical TAS and IL-4 concentrations., Conclusions: OLE suppressed LPS-related astrocyte and microglial activation in the hippocampus and cortex. The OLE-induced increase in cortical IL-4 concentrations indicates the induction of an anti-inflammatory phenotype of microglia. OLE may also modulate astrocyte and IL-17A functions, which could explain its opposing effects on hippocampal GFAP immunoreactivity and IL-17A concentrations when administered with or without LPS., (Copyright © 2024 American Society for Nutrition. Published by Elsevier Inc. All rights reserved.)

Keratin 6A (KRT6A) is involved in the pathogenesis of various skin diseases. However, the reports on the roles of KRT6A in atopic dermatitis (AD) are limited. This study aimed to investigate the potentials of KRT6A in AD. mRNA levels were detected by RT-PCR. Cytokine release was determined by ELISA. Protein expression was determined using Western blot. Cell viability was determined by CCK-8. Cytotoxicity was detected by LDH assay. Cell death was determined by TUNEL. The pyroptosis of keratinocytes was detected using flow cytometry. We found that KRT6A was overexpressed in AD patients. Moreover, KRT6A was stimulated after exposed to proinflammatory cytokines. Overexpressed KRT6A suppressed inflammatory response, while KRT6A knockdown exerted the opposite effects. Overexpressed KRT6A suppressed inflammation-induced pyroptosis of keratinocytes. Additionally, KRT6A negatively regulated interleukin-17a (IL-17a) expression, blocking IL-17 signaling. IL-17a overexpression antagonized the effects of KRT6A and promoted pyroptosis of keratinocytes. In conclusion, KRT6A exerted protective functions in AD via regulating IL-17 signaling. This KRT6A/IL-17 may be a novel target for AD.

Interleukin-17A (IL-17A) is a pro-inflammatory cytokine implicated in diverse autoimmune and inflammatory disorders such as psoriasis and Kawasaki disease. Mature IL-17A is a homodimer that binds to the extracellular type-III fibronectin D1:D2-dual domain of its cognate IL-17 receptor A (IL-17RA). In this study, we systematically examined the structural basis, thermodynamics property, and dynamics behavior of IL-17RA/IL-17A interaction and computationally identified two continuous hotspot regions separately from different monomers of IL-17A homodimer that contribute significantly to the interaction, namely I-shaped and U-shaped segments, thus rendered as a peptide-mediated protein-protein interaction (PmPPI). Self-inhibitory peptides (SIPs) are derived from the two segments to disrupt IL-17RA/IL-17A interaction by competitively rebinding to the IL-17A-binding pocket on IL-17RA surface, which, however, only have a weak affinity and low specificity for IL-17RA due to lack of the context support of intact IL-17A protein, thus exhibiting a large flexibility and intrinsic disorder when splitting from the protein context and incurring a considerable entropy penalty when rebinding to IL-17RA. The U-shaped segment is further extended, mutated and stapled by a disulfide bridge across its two strands to obtain a number of double-stranded cyclic SIPs, which are partially ordered and conformationally similar to their native status at IL-17RA/IL-17A complex interface. Experimental fluorescence polarization assays substantiate that the stapling can moderately or considerably improve the binding affinity of U-shaped segment-derived peptides by 2-5-fold. In addition, computational structural modeling also reveals that the stapled peptides can bind in a similar mode with the native crystal conformation of U-shaped segment in IL-17RA pocket, where the disulfide bridge is out of the pocket for avoiding intervene of the peptide binding., (© 2023 John Wiley & Sons Ltd.)

Recently, we have reported that the early progression of proteinuria in the obese Dahl salt-sensitive (SS) leptin receptor mutant (SS LepR mutant) strain was associated with increased renal macrophage infiltration before puberty. Macrophages can be divided into two distinct phenotypes: M1 (proinflammatory) and M2 (anti-inflammatory). Moreover, previous studies have demonstrated that interleukin (IL)-25 converts resting macrophages and M1 into M2. Therefore, the present study examined whether treatment with IL-25 would reduce the early progression of renal injury in SS LepR mutant rats by increasing renal M2. We also investigated the impact of IL-25 on M2 subtypes: M2a (wound healing/anti-inflammatory), M2b (immune mediated/proinflammatory), M2c (regulatory/anti-inflammatory), and M2d (tumor associated/proangiogenic). Four-wk-old SS and SS LepR mutant rats were treated with either control (IgG) or IL-25 (1 µg/day ip every other day) for 4 wk. The kidneys from SS LepR mutant rats displayed progressive proteinuria and renal histopathology versus SS rats. IL-25 treatment had no effect on these parameters in SS rats. However, in the SS LepR mutant strain, proteinuria was markedly reduced after IL-25 treatment. Chronic treatment with IL-25 significantly decreased glomerular and tubular injury and renal fibrosis in the SS LepR mutant strain. Although the administration of IL-25 did not change total renal macrophage infiltration in both SS and SS LepR mutant rats, IL-25 increased M2a by >50% and reduced M1 by 60% in the kidneys of SS LepR mutant rats. Overall, these data indicate that IL-25 reduces the early progression of renal injury in SS LepR mutant rats by inducing M2a and suppressing M1 and suggest that IL-25 may be a therapeutic target for renal disease associated with obesity. NEW & NOTEWORTHY For the past few decades, immune cells and inflammatory cytokines have been demonstrated to play an important role in the development of renal disease. The present study provides strong evidence that interleukin-25 slows the early progression of renal injury in obese Dahl salt-sensitive rats before puberty by increasing systemic anti-inflammatory cytokines and renal M2a macrophages.

Objective: To explore the effect of interleukin-17A (IL-17A) on liver and kidney injury and prognosis in septic mice., Methods: A total of 84 SPF male C57BL/6 mice were randomly divided into sham operation group (Sham group), cecal ligation and puncture (CLP) induced sepsis model group (CLP group), and IL-17A intervention group. IL-17A intervention group were then divided into five subgroups according to the dose of IL-17A (0.25, 0.5, 1, 2, 4 μg). Mice in the IL-17A intervention group were intraperitoneally injected with the corresponding dose of IL-17A 100 μL immediately after surgery. The other groups were intraperitoneally injected with 100 μL phosphate buffer solution (PBS). The survival rate of mice was observed at 7 days, and peripheral blood and liver, kidney and spleen tissues were collected. According to the 7-day survival, another 18 mice were randomly divided into Sham group, CLP group, and 1 μg IL-17A intervention group. Peripheral blood samples were collected at 12 hours and 24 hours after CLP, and the mice were sacrificed to obtain liver, kidney, and spleen tissues. The behavior and abdominal cavity of each group were observed. The levels of peripheral blood liver and kidney function indexes and inflammatory factors were detected. The histopathological changes of liver and kidney were observed under light microscope. The peripheral blood and spleen tissues were inoculated in the medium, the number of bacterial colonies was calculated, and the bacterial migration of each group was evaluated in vitro., Results: Except for the Sham group, the 7-day survival rate of mice in the 1 μg IL-17A intervention group was the highest (75.0%), so this condition was selected as the intervention condition for the subsequent study. Compared with Sham group, the liver and kidney functions of CLP group were significantly damaged at each time point after operation. Alanine aminotransferase (ALT), aspartate aminotransferase (AST), blood urea nitrogen (BUN) and serum creatinine (SCr) reached the peak at 24 hours after operation, and the liver and kidney pathological scores reached the peak at 7 days after operation, the levels of inflammatory cytokines interleukin (IL-17A, IL-6, IL-10) reached the peak at 12 hours after operation, and tumor necrosis factor-α (TNF-α) reached the peak at 24 hours after operation. In addition, a large number of bacteria proliferated in the peripheral blood and spleen, which reached the peak on day 7. Compared with the CLP group, exogenous administration of 1 μg IL-17A significantly delayed the rising trend of each index in the early stage of sepsis [24-hour ALT (U/L): 166.95±5.20 vs. 271.30±6.11, 24-hour AST (U/L): 599.42±7.25 vs. 1 013.27±3.37, 24-hour BUN (mg/L): 815.4±26.3 vs. 1 191.2±39.4, 24-hour SCr (μmol/L): 29.34±0.87 vs. 60.75±3.83, 7-day liver pathological score: 2.50 (2.00, 3.00) vs. 9.00 (8.50, 9.00), 7-day kidney pathological score: 1.00 (1.00, 2.00) vs. 5.00 (4.50, 5.00), 12-hour IL-17A (ng/L): 105.21±0.31 vs. 111.28±1.37, 12-hour IL-6 (ng/L): 83.22±1.01 vs. 108.88±0.99, 12-hour IL-10 (ng/L): 731.54±3.04 vs. 790.25±2.54, 24-hour TNF-α (μg/L): 454.67±0.66 vs. 576.18±0.76, 7-day peripheral blood colony count (CFU/mL): 600 (400, 600) vs. 4 200 (4 200, 4 300), 7-day spleen tissue colony count (CFU/g): 4 600 (4 400, 4 600) vs. 23 400 (23 200, 23 500), all P < 0.05]., Conclusions: Appropriate dose (1 μg) of exogenous IL-17A can reduce the lethal inflammatory response induced by CLP and improve the ability of bacterial clearance, thereby alleviating liver and kidney injury and improving the 7-day survival rate of septic mice.

Dynamic Network Analysis (DyNA) and Dynamic Hypergraphs (DyHyp) were used to define protein-level inflammatory networks at the local (wound effluent) and systemic circulation (serum) levels from 140 active-duty, injured service members (59 with TBI and 81 non-TBI). Interleukin (IL)-17A was the only biomarker elevated significantly in both serum and effluent in TBI vs. non-TBI casualties, and the mediator with the most DyNA connections in TBI wounds. DyNA combining serum and effluent data to define cross-compartment correlations suggested that IL-17A bridges local and systemic circulation at late time points. DyHyp suggested that systemic IL-17A upregulation in TBI patients was associated with tumor necrosis factor-α, while IL-17A downregulation in non-TBI patients was associated with interferon-γ. Correlation analysis suggested differential upregulation of pathogenic Th17 cells, non-pathogenic Th17 cells, and memory/effector T cells. This was associated with reduced procalcitonin in both effluent and serum of TBI patients, in support of an antibacterial effect of Th17 cells in TBI patients. Dysregulation of Th17 responses following TBI may drive cross-compartment inflammation following combat injury, counteracting wound infection at the cost of elevated systemic inflammation., (© 2023. The Author(s).)

Rheumatoid arthritis (RA) is an autoimmune disease with chronic inflammation, bone erosion, and joint deformation. Synovial tissue in RA patients is full of proinflammatory cytokines and infiltrated immune cells, such as T help (Th) 9, Th17, macrophages, and osteoclasts. Recent reports emphasized a new member of the interleukin (IL)-10 family, IL-26, an inducer of IL-17A that is overexpressed in RA patients. Our previous works found that IL-26 inhibits osteoclastogenesis and conducts monocyte differentiation toward M1 macrophages. In this study, we aimed to clarify the effect of IL-26 on macrophages linking to Th9 and Th17 in IL-9 and IL-17 expression and downstream signal transduction. Murine and human macrophage cell lines and primary culture cells were used and stimulated by IL26. Cytokines expressions were evaluated by flow cytometry. Signal transduction and transcription factors expression were detected by Western blot and real time-PCR. Our results show that IL-26 and IL-9 colocalized in macrophage in RA synovium. IL-26 directly induces macrophage inflammatory cytokines IL-9 and IL-17A expression. IL-26 increases the IL-9 and IL-17A upstream mechanisms IRF4 and RelB expression. Moreover, the AKT-FoxO1 pathway is also activated by IL-26 in IL-9 and IL-17A expressing macrophage. Blockage of AKT phosphorylation enhances IL-26 stimulating IL-9-producing macrophage cells. In conclusion, our results support that IL-26 promotes IL-9- and IL-17-expressing macrophage and might initiate IL-9- and IL-17-related adaptive immunity in rheumatoid arthritis. Targeting IL-26 may a potential therapeutic strategy for rheumatoid arthritis or other IL-9 plus IL-17 dominant diseases.

The inflammatory cytokine IL-17A is known to have the capacity to promote osteoclastogenesis, thereby enhancing bone loss. Moreover, IL-17A can promote the expression of RANKL in osteoblasts, contributing to its pro-osteoclastogenic effect. IL-17A is an autophagy regulator, which is also responsible for its regulation on RANKL expression. However, the specific role of autophagy in IL-17A-regulated RANKL expression and the underlying mechanism of IL-17A-regulated osteoblast autophagy remain unclear. IL-17A is known to inhibit autophagy by preventing BCL2 degradation. This study aimed to explore the significance of BCL2-dependent autophagy in IL-17A-regulated RANKL expression. Our results showed that IL-17A at 50 ng/mL could inhibit autophagic activity and promote RANKL protein expression in MC3T3-E1 osteoblast line. Moreover, the corresponding concentration of IL-17A could enhance BCL2 protein expression and the protein interaction between BCL2 and Beclin1 in MC3T3-E1 cells. However, the protein expression of RANKL and BCL2 promoted by 50 ng/mL of IL-17A was blocked by autophagy activation with Beclin1 pharmacological upregulation. Furthermore, RANKL protein expression promoted by 50 ng/mL of IL-17A was also reversed by autophagy activation with BCL2 knockdown. Importantly, the supernatant from osteoblasts treated with 50 ng/mL of IL-17A made osteoclast precursors (OCPs) form larger osteoclasts, which was reversed by BCL2 knockdown in osteoblasts. In conclusion, high levels of IL-17A prevent the degradation of RANKL by inhibiting BCL2-Beclin1-autophagy activation signal transduction in osteoblasts, thereby indirectly promoting osteoclastogenesis., (© 2023. The Society for In Vitro Biology.)

Bone is a frequent target of tumor metastasis, with high incidence rate and poor prognosis. Osteoclasts play a key role in the process of tumor bone metastasis. Interleukin-17A (IL-17A) is an inflammatory cytokine, highly expressed in a variety of tumor cells, that can alter the autophagic activity of other cells, thereby causing corresponding lesions. Previous studies have shown that low concentration IL-17A can promote osteoclastogenesis. The aim of this study was to clarify the mechanism of low concentration IL-17A promoting osteoclastogenesis by regulating autophagic activity. The results of our study showed that IL-17A could promote the differentiation of osteoclast precursors (OCPs) into osteoclasts in the presence of RANKL, and increase the mRNA levels of osteoclast-specific genes. Moreover, IL-17A increased the expression of Beclin1 by inhibiting the phosphorylation of ERK and mTOR, leading to enhanced autophagy of OCPs, accompanied by decreased OCP apoptosis. Furthermore, knockdown of Beclin1 and suppression of autophagy by 3-methyladenine (3-MA) significantly attenuated the enhanced osteoclastogenesis induced by IL-17A. In summary, these results indicate that low concentration IL-17A enhances the autophagic activity of OCPs through the ERK/mTOR/Beclin1 pathway during osteoclastogenesis, and further promotes osteoclast differentiation, suggesting that IL-17A may serve as a potential therapeutic target for cancer-related bone resorption in cancer patients., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Tang et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Endothelial aging is a sign of vascular aging that predisposes patients to vascular disease. We explored the effects of IL-17A on endothelial cell aging and determined the potential underlying mechanisms. In human umbilical vein endothelial cells, IL-17A promoted senescence, evidenced as increased positive staining of senescence-associated β-galactosidase, increased proportion of cells arrested at G0/G1 stage, and upregulated p21 and p16 expression. IL-17A increased the expression of the m6A methylase FTO. We then investigated the relationship between FTO and endothelial cell aging. After interfering with FTO expression by siRNA, we observed that FTO induced endothelial cell aging. An increase in the expression of p-Jun N-terminal kinases (JNK) increased after IL-17A treatment indicated, that the JNK signaling pathway affected FTO expression. Moreover, the addition of the JNK signaling pathway inhibitor SP600125 blocked the effect of IL-17A on FTO expression. In conclusion, our findings revealed that IL-17A can promote endothelial cell aging by activating the JNK signaling pathway and upregulating FTO expression. This discovery can help in the identification of new therapeutic targets against endothelial cell aging and related vascular complications., (© 2022. The Author(s), under exclusive licence to Springer Nature B.V.)

Psoriasis is a chronic multisystemic inflammatory disease with inflammatory cell infiltration, hyperproliferation of keratinocytes in skin lesions, and epidermal barrier dysfunction. Normal human epidermal keratinocytes (NHEKs) were stimulated with interleukin 17A (IL-17A). The expression levels of sirtuin-5 (SIRT5) were analyzed by RT-qPCR and western blot assay. The proliferation levels of NHEKs were assessed by EdU staining. The expression of ELOVL1 and ELOVL4 was analyzed by RT-Qpcr, and the expression levels of filaggrin, loricrin, and aquaporin-3 were analyzed by RT-qPCR and western blot. Extracellular signal-regulated kinase 1/2 (ERK1/2) activator t-butylhydroquinone was used to activate ERK1/2. Here, we show that SIRT5 overexpression reduces cell viability and cell proliferation, and improves barrier dysfunction in IL-17A-treated human epidermal keratinocytes, this effect of which is significantly blunted by the ERK1/2 activator. In epidermal keratinocytes, SIRT5 decreases cell proliferation and inflammation and improves barrier dysfunction via ERK/STAT3. This study reveals the role of SIRT5 in the pathogenesis of psoriasis, epidermal hyperplasia, keratinocyte-mediated inflammatory responses, and barrier dysfunction, the role of which is mediated by ERK/STAT3.

This study aimed to investigate the effects of interleukin-25, which belongs to the interleukin-17 family, on short-term high-fructose diet-induced hepatic triacylglycerol accumulation. Rats were fed a high-starch (control) or high-fructose diet for 7 d, with or without intraperitoneal administration of recombinant interleukin-25 from days 3-7. Treatment with interleukin-25 significantly reduced the mRNA levels and activity of fatty acid synthesis enzymes and caused a nominal reduction in hepatic triacylglycerol levels in rats fed a high-fructose diet but not in those fed a control diet. Interleukin-25 treatment did not affect the mRNA levels of β-oxidation enzymes in either the control or fructose-fed rats. These results suggest that treatment with interleukin-25 suppresses short-term high-fructose diet-induced fatty acid synthesis and leads to the alleviation of triacylglycerol accumulation in the liver.

Objective: To investigate the effects of Compaximab and raizumab on retinal function and serum interleukin-17A level in retinopathy of prematurity., Methods: Sixty cases of retinopathy of prematurity treated in our hospital from February 2019 to April 2021 were selected. The patients were randomly divided into control group ( n = 30) and research group ( n = 30). The control group was treated with Compaq and the research group was treated with razumab. The curative effect, retinal function, incidence of complications, intraocular pressure at different time, and the level of serum interleukin-17A were compared., Results: Compared with the two groups, the curative effect of the research group 93.33% (28/30) was greater than that of the control group 66.67% (20/30), and the difference was statistically significant ( P < 0.05). Compared with the incidence of complications, the incidence of corneal opacity, lens opacity, preretinal and vitreous hemorrhage, endophthalmitis, and traction retinal detachment in the research group was greatly lower, and the difference was statistically significant ( P < 0.05). Following the therapy, the IOP of the two groups decreased at different times. The IOP of 1 min, 10 min, and 30 min in the research group was obviously lower, and the difference was statistically significant ( P < 0.05). Following treatments, the levels of serum IL-17A were decreased. Compared with the control group, the level of serum IL-17A in the research group was greatly downregulated, and the difference was statistically significant ( P < 0.05)., Conclusion: Intravitreal injection of razumab is an effective treatment for retinopathy of prematurity, which can effectively improve the retinal function of infants. The level of serum interleukin-17A can be reduced and intraocular pressure can be regulated, which is safe and effective., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2022 Huixuan Ren et al.)

Psoriasis is a recurrent inflammatory skin disorder characterized by epidermal hyperplasia, which is primarily driven by IL-17A. The Hippo-YAP signaling pathway plays a vital role in cell survival and tissue growth, and its target gene, AREG, has been reported to promote the development of psoriasis. However, whether IL-17A promotes keratinocyte proliferation through regulating Hippo-YAP signaling has not been explored. In this study, we show that the YAP-AREG pathway is activated in human psoriatic skin and is suppressed by IL-17A antagonist secukinumab and that imiquimod and IL-17A administration activates the YAP-AREG axis in mice epidermis. In vitro studies using HaCaT and normal human epidermal keratinocyte cells suggest that IL-17A enhances AREG expression and keratinocyte proliferation by activating Hippo-YAP signaling. Mechanistically, IL-17A stimulates the recruitment of MST1 to ACT1 in keratinocytes, which leads to reduced MST1-LATS1 interaction and YAP dephosphorylation. Together, our findings reveal a previously unknown mechanism in which IL-17A promotes keratinocyte proliferation in psoriasis, namely through activating YAP-AREG signaling., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Psoriasis is an immune-mediated inflammatory skin disease, in which an interplay between infiltrating immune cells and keratinocytes sustains chronic skin inflammation. Interleukin (IL)-17A is a key inflammatory cytokine in psoriasis and its main cellular targets are keratinocytes., Objectives: To explore the role of miR-378a in psoriasis., Methods: Keratinocytes obtained from psoriatic skin and healthy epidermis were separated by magnetic sorting, and the expression of miR-378a was analysed by quantitative polymerase chain reaction. The regulation and function of miR-378a was studied using primary human keratinocytes. The expression of miR-378a was modulated by synthetic mimics, and nuclear factor kappa B (NF-κB) activity and transcriptomic changes were studied. Synthetic miR-378a was delivered to mouse skin in conjunction with induction of psoriasiform skin inflammation by imiquimod., Results: We show that miR-378a is induced by IL-17A in keratinocytes through NF-κB, C/EBP-β and IκBζ and that it is overexpressed in psoriatic epidermis. In cultured keratinocytes, ectopic expression of miR-378a resulted in the nuclear translocation of p65 and enhanced NF-κB-driven promoter activity even in the absence of inflammatory stimuli. Moreover, miR-378a potentiated the effect of IL-17A on NF-κB nuclear translocation and downstream activation of the NF-κB pathway. Finally, injection of miR-378a into mouse skin augmented psoriasis-like skin inflammation with increased epidermal proliferation and induction of inflammatory mediators. Mechanistically, miR-378a acts as a suppressor of NFKBIA/IκBζ, an important negative regulator of the NF-κB pathway in keratinocytes., Conclusions: Collectively, our findings identify miR-378a as an amplifier of IL-17A-induced NF-κB signalling in keratinocytes and suggest that increased miR-378a levels contribute to the amplification of IL-17A-driven skin inflammation in psoriasis., (© 2022 The Authors. British Journal of Dermatology published by John Wiley & Sons Ltd on behalf of British Association of Dermatologists.)

IL-17 cytokines are expressed by numerous cells (e.g., gamma delta (γδ) T, innate lymphoid (ILC), Th17, epithelial cells). They contribute to the elimination of bacteria through the induction of cytokines and chemokines which mediate the recruitment of inflammatory cells to the site of infection. However, IL-17-driven inflammation also likely promotes the progression of chronic lung diseases, such as chronic obstructive pulmonary disease (COPD), lung cancer, cystic fibrosis, and asthma. In this review, we highlight the role of IL-17 cytokines in chronic lung diseases.

Asthma is a common heterogeneous respiratory disease characterized by airway inflammation and airway hyperresponsiveness (AHR) which is associated with abnormality in smooth muscle contractility. The epithelial cell-derived cytokine IL-25 is implicated in type 2 immune pathology including asthma, whereas the underlying mechanisms have not been fully elucidated. This study aims to investigate the effects of IL-25 on mouse tracheal smooth muscle contractility and elucidate the cellular mechanisms. Incubation with IL-25 augmented the contraction of mouse tracheal smooth muscles, which could be suppressed by the L-type voltage-dependent Ca 2+ channel (L-VDCC) blocker nifedipine. Furthermore, IL-25 enhanced the cytosolic Ca 2+ signals and triggered the upregulation of α1C L-VDCC (Ca V 1.2) in primary cultured mouse tracheal smooth muscle cells. Knocking down IL-17RA/IL-17RB receptors or inhibiting the transforming growth factor-β-activated kinase 1 (TAK1)-tumor progression locus 2 (TPL2)-MAPK kinase 1/2 (MEK1/2)-ERK1/2-activating protein-1 (AP-1) signaling pathways suppressed the IL-25-elicited upregulation of Ca V 1.2 and hyperreactivity in tracheal smooth muscles. Moreover, inhibition of TPL2, ERK1/2 or L-VDCC alleviated the AHR symptom induced by IL-25 in a murine model. This study revealed that IL-25 potentiated the contraction of tracheal smooth muscle and evoked AHR via activation of TPL2-ERK1/2-Ca V 1.2 signaling, providing novel targets for the treatment of asthma with a high-IL-25 phenotype.

Background: Angiogenesis associates with chondrocytes differentiation in inflammatory arthritis. Interleukin (IL)- 1β stimulated SW1353 cells have a phenotype similar to this kind of chondrocytes. IL-17A, a target in T helper 17 (Th17)/IL-17 signaling pathways, was expressed by SW1353 cells. The study aimed to explore the role of IL-35 on angiogenesis in IL-1β stimulated SW1353 cells and its related signaling pathways., Methods: Microarray dataset was downloaded from the Gene Expression Omnibus database of arthritis cartilage. The protein-protein interaction (PPI) was analyzed for IL-35, pro-angiogenic factors and the differentially expressed genes (DEGs). We studied the effects of IL-35 on proliferation and apoptosis in IL-1β stimulated SW1353 cells using cell counting kit-8 (CCK-8) assay and flow cytometry. The expression of pro-angiogenic factors and IL-17A were assessed by western blot and real-time PCR. Added plumbagin (inhibitor of IL-17A) to repeat the above experiment. The secretion of IL-17A was assessed by ELISA., Results: IL-35, pro-angiogenic factors interacted with DEGs to affect the function of arthritis chondrocytes. IL-35 promoted IL-1β-stimulated SW1353 cells proliferation, inhibited apoptosis, and decreased pro-angiogenic molecules and IL-17A expression in a concentration dependent manner. IL-35 inhibited IL-17A secretion in the supernatants of these cells. Blocking the Th17/IL-17 related pathways with plumbagin abolished the effects of IL-35 on IL-1β-stimulated SW1353 cells., Conclusion: These results suggested that IL-35 regulated differentiation and pro-angiogenic molecules expression in IL-1β stimulated SW1353 cells via Th17/IL-17 related signaling pathways. Our findings may reveal the mechanisms of novel angiogenesis molecules in inflammatory chondrocyte lesion., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Immune rejection is the major limitation for porcine xenograft survival in primate recipients. Proinflammatory cytokines play important roles in immune rejection and have been found to mediate the pathological effects in various clinical and experimental transplantation trials. IL-17 and TNF-α play critical pathological roles in immune disorders, such as psoriasis and rheumatoid arthritis. However, the pathological roles of human IL-17 (hIL-17) and human TNF-α (hTNF-α) in xenotransplantation remain unclear. Here we found that hIL-17 and hTNF-α additively or synergistically regulate the expression of 697 genes in porcine aortic endothelial cells (PAECs). Overall, 415 genes were found to be synergistically regulated, while 282 genes were found to be additively regulated. Among these, 315 genes were upregulated and 382 genes were downregulated in PAECs. Furthermore, we found that hIL-17 and hTNF-α additively or synergistically induced the expression of various proinflammatory cytokines and chemokines ( e . g ., IL1α, IL6, and CXCL8) and decreased the expression of certain anti-inflammatory genes ( e . g ., IL10). Moreover, hIL-17 plus hTNF-α increased the expression of IL1R1 and IL6ST, receptors for IL1 and IL6, respectively, and decreased anti-inflammatory gene receptor expression (IL10R). hIL-17 and hTNF-α synergistically or additively induced CXCL8 and CCL2 expression and consequently promoted primary human neutrophil and human leukemia monocytic cell migration, respectively. In addition, hIL-17 and hTNF-α induced pro-coagulation gene (SERPINB2 and F3) expression and decreased anti-coagulation gene (TFPI, THBS1, and THBD) expression. Additionally, hIL-17 and hTNF-α synergistically decreased occludin expression and consequently promoted human antibody-mediated complement-dependent cytotoxicity. Interestingly, hTNF-α increased swine leukocyte antigen (SLA) class I expression; however, hIL-17 decreased TNF-α-mediated SLA-I upregulation. We concluded that hIL-17 and hTNF-α likely promote the inflammatory response, coagulation cascade, and xenoantibody-mediated cell injury. Thus, blockade of hIL-17 and hTNF-α together might be beneficial for xenograft survival in recipients., Competing Interests: The authors declare that this research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Li, Chen, Zhao, Cao, Hu, Pan, Sun, Huang, Wu, Song, Zhong, Mou, Luan, Chen and Gao.)

Asthmatics have elevated levels of IL-17A compared to healthy controls. IL-17A is likely to contribute to reduced corticosteroid sensitivity of human airway epithelium. Here, we aimed to investigate the mechanistic underpinnings of this reduced sensitivity in more detail. Differentiated primary human airway epithelial cells (hAECs) were exposed to IL-17A in the absence or presence of dexamethasone. Cells were then collected for RNA sequencing analysis or used for barrier function experiments. Mucus was collected for volume measurement and basal medium for cytokine analysis. 2861 genes were differentially expressed by IL-17A (Padj < 0.05), of which the majority was not sensitive to dexamethasone (< 50% inhibition). IL-17A did inhibit canonical corticosteroid genes, such as HSD11B2 and FKBP5 (p < 0.05). Inflammatory and goblet cell metaplasia markers, cytokine secretion and mucus production were all induced by IL-17A, and these effects were not prevented by dexamethasone. Dexamethasone did reverse IL-17A-stimulated epithelial barrier disruption, and this was associated with gene expression changes related to cilia function and development. We conclude that IL-17A induces function-specific corticosteroid-insensitivity. Whereas inflammatory response genes and mucus production in primary hAECs in response to IL-17A were corticosteroid-insensitive, corticosteroids were able to reverse IL-17A-induced epithelial barrier disruption., (© 2022. The Author(s).)

Background: Vascular calcification is characterized by mineral deposition in the vasculature, which is triggered by chronic systemic inflammation, including psoriasis. Psoriasis is an IL-17A-mediated inflammatory skin disease that is associated with exacerbated vascular calcification and high cardiovascular mortality. Although previous studies have shown that IL-17A induces vascular dysfunction in murine psoriasis models, it has not been clarified whether IL-17A induces vascular calcification. In this study, we investigated the potential vascular calcification-inducing effect of IL-17A in an ex vivo culture system., Methods: Thoracic and abdominal aortas from mice were cultured in a medium supplemented with inorganic phosphate and were treated with inflammatory cytokines (IL-1β, TNF-α, IL-6, and IL-17A). Vascular calcification was determined using micro-computed tomography (CT) and histological analyses., Results: IL-1β, TNF-α, and IL-6 did not significantly promote vascular calcification, whereas IL-17A significantly accelerated vascular calcification of the aorta, as indicated by the increased mineralized volume based on micro-CT analysis. Micro-CT and histological analyses also revealed that the promoting effect of IL-17A on vascular calcification was concentration dependent., Conclusions: IL-17A significantly promoted vascular calcification in ex vivo cultured aortas, which suggests that this mechanism is involved in the increased risk of cardiovascular events in IL-17A-mediated inflammatory diseases., Competing Interests: Declaration of competing interest S.H.A., T.A., S.F., K.N., and Y.M. received scholarship donations from AbbVie, Asahi Kasei, Ayumi, and Chugai. The other authors declare no conflicts of interest., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Rationale: Non-allergic asthma is driven by multiple endotypes of which neutrophilic and pauci-granulocytic asthma have been best established. However, it is still puzzling what drives inflammation and airway hyperreactivity (AHR) in these patients and how it can be treated effectively. Recently, a potential role of the innate immune system and especially the innate lymphoid cells (ILC) has been proposed., Objective: In this study, we investigated the effects of LPS inhalation on airway inflammation and AHR as a potential model for elucidating the pathogenesis of non-allergic asthma., Methods: Wild-type (BALB/c), SCID, IL-17A -/- , and Rag2 -/- γC -/- mice were endonasally exposed to lipopolysaccharide (LPS, 2 µg) on four consecutive days. Twenty-four hours after the last exposure, AHR to methacholine was assessed. Cytokine levels and ILC subpopulations were determined in lung tissue. Cellular differential analysis was performed in BAL fluid., Main Results: In this study, we developed a murine model for non-allergic neutrophilic asthma. We found that repeated endonasal applications of low-dose LPS in BALB/c mice led to AHR, BAL neutrophilia, and a significant increase in lung ILC3 as well as a significant increase in lung chemokines KC and MIP-2 and cytokines IL-1β, IL-17A, IL-22, and TNF. The adoptive transfer of ILC in Rag2 -/- γC -/- mice showed that ILC played a causal role in the induction of AHR in this model. Antagonising IL-1β, but not IL-17A or neutrophils, resulted in a partial reduction in LPS-induced AHR., Conclusion: In conclusion, we report here a murine model for neutrophilic asthma where ILC are required to induce airway hyperreactivity., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Jonckheere, Seys, Steelant, Decaesteker, Dekoster, Cremer, Dilissen, Schols, Iwakura, Vande Velde, Breynaert, Schrijvers, Vanoirbeek, Ceuppens, Dupont and Bullens.)

To investigate the effect of Interleukin 17 (IL-17) on the invasive capacity of trophoblast cells and the underlying mechanism, we collected placental tissues samples from pregnant women with preeclampsia (PE) and healthy pregnant women. The expression levels of IL-17 mRNA and protein in tissue samples were determined using qRT-PCR and Western blot, respectively. Cell viability and cell proliferation was determined using CCK-8 assay, and colony formation assay, respectively. Cell migration and invasion capacity were determined using transwell cell migration assay. Our results showed that the mRNA expression of IL-17 was significantly increased in PE patients and may be used as a sensitive biomarker for PE ( P < 0.01). IL-17 overexpression promoted cell viability, migration, and invasion of human extravillous trophoblast cell line, HTR8/SVneo; however, IL-17 knockdown inhibited these effects. Additionally, IL-17 activated PPAR-γ/RXR-α signaling pathway, which promoted proliferation, migration, and invasion of trophoblast cells. Moreover, PPAR-γ/RXR-α heterodimers activated Wnt signaling. In conclusion, our study provides evidence that IL-17 is overexpressed in PE and promotes proliferation, migration and invasion of trophoblast cells via activating PPAR-γ/RXR-α/Wnt signaling.

DNA methylation is an epigenetic mechanism controlling gene expression, and reduced methylation is associated with increased gene expression. We hypothesized that IL-17 cytokines are regulated by DNA methylation, are elevated in the circulation of preeclamptic women, and stimulate vascular neutrophil chemokine expression, which could account for vascular infiltration of neutrophils in preeclampsia. We found significantly reduced DNA methylation of IL17A, IL17E, and IL17F genes in omental arteries of preeclamptic women, significantly reduced methylation of IL2, which regulates IL-17-producing T-lymphocytes, and significantly reduced methylation of genes encoding neutrophil chemokines and TNFα receptors related to lymphocyte function. Maternal plasma levels of IL-17A were significantly elevated in the second trimester of preeclamptic pregnancy as compared to normal pregnancy. To test if methylation regulates IL-17 cytokines, a lymphocyte cell line (Jurkat) was cultured with a hypomethylating agent. Hypomethylation increased expression of IL17E (aka IL25), IL17F, and IL2. IL17A was not expressed by Jurkat cells. To test the potential role of IL-17 cytokines in vascular neutrophil infiltration associated with preeclampsia, human vascular smooth muscle cells were cultured with IL-17 cytokines. IL-17A, but not IL-17E or IL-17F, increased gene expression of neutrophil chemokines (IL-8, CXCL5, and CXCL6) that are increased in vascular smooth muscle of preeclamptic women. The monocyte chemokine, CCL-2, was not increased. TNFα also increased neutrophil chemokines. IL-17 cytokines are regulated by DNA methylation; IL-17A is elevated in preeclampsia and stimulates expression of neutrophil chemokines in vascular smooth muscle. IL-17A could be responsible for vascular infiltration of neutrophils in preeclampsia., (© 2021. Society for Reproductive Investigation.)

Interleukin (IL)-25 is a cytokine released by airway epithelial cells responding to pathogens. Excessive production of reactive oxygen species (ROS) leads to airway inflammation and remodeling in asthma. Mitochondria are the major source of ROS. After stress, defective mitochondria often undergo selective degradation, known as mitophagy. In this study, we examined the effects of IL-25 on ROS production and mitophagy and investigated the underlying mechanisms. The human monocyte cell line was pretreated with IL-25 at different time points. ROS production was measured by flow cytometry. The involvement of mitochondrial activity in the effects of IL-25 on ROS production and subsequent mitophagy was evaluated by enzyme-linked immunosorbent assay, Western blotting, and confocal microscopy. IL-25 stimulation alone induced ROS production and was suppressed by N-acetylcysteine, vitamin C, antimycin A, and MitoTEMPO. The activity of mitochondrial complex I and complex II/III and the levels of p-AMPK and the mitophagy-related proteins were increased by IL-25 stimulation. The CCL-22 secretion was increased by IL-25 stimulation and suppressed by mitophagy inhibitor treatment and PINK1 knockdown. The Th2-like cytokine IL-25 can induce ROS production, increase mitochondrial respiratory chain complex activity, subsequently activate AMPK, and induce mitophagy to stimulate M2 macrophage polarization in monocytes.

The recent advances in our understanding of the host factors in orchestrating qualitatively different immune responses against influenza Type A virus (IAV) have changed the perception of conventional approaches for controlling avian influenza virus (AIV) infection in chickens. Given that infection-induced pathogenicity and replication of influenza virus largely rely on regulating host immune responses, immunoregulatory cytokine profiles often determine the disease outcomes. However, in contrast to the function of other inflammatory cytokines, interleukin-17A (IL-17A) has been described as a 'double-edged sword', indicating that in addition to antiviral host responses, IL-17A has a distinct role in promoting viral infection. Therefore, in the present study, we investigated the chicken IL-17A mediated antiviral immune effects on IAVs infection in primary chicken embryo fibroblasts cells (CEFs). To this end, we first bioengineered a food-grade Lactic Acid Producing Bacteria (LAB), Lactococcus lactis (L. lactis), secreting bioactive recombinant chicken IL-17A (sChIL-17A). Next, the functionality of sChIL-17A was confirmed by transcriptional upregulation of several genes associated with antiviral host responses, including granulocyte-monocyte colony-stimulating factor (GM-CSF) (CSF3 in the chickens), interleukin-6 (IL-6), interferon-α (IFN-α), -β and -γ genes in primary CEFs cells. Consistent with our hypothesis that such a pro-inflammatory state may translate to immunoprotection against IAVs infection, we observed that sChIL-17A pre-treatment could significantly limit the viral replication and protect the primary CEFs cells against two heterotypic IAVs such as A/turkey/Wisconsin/1/1966(H9N2) and A/PR/8/1934(H1N1). Together, the data presented in this work suggest that exogenous application of sChIL-17A secreted by modified LAB vector may represent an alternative strategy for improving antiviral immunity against avian influenza virus infection in chickens., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

[Figure: see text].

Mesenchymal stem cells (MSCs) have been identified within dental pulp tissues of exfoliated deciduous (SHEDs) and permanent (DPSCs) teeth. Although differences in their proliferative and differentiation properties were revealed, variability in SHEDs and DPSCs responsiveness to growth factors and cytokines have not been studied before. Here, we investigated the influence of interleukin-17 (IL-17) and basic fibroblast growth factor (bFGF) on stemness features of SHEDs and DPSCs by analyzing their proliferation, clonogenicity, cell cycle progression, pluripotency markers expression and differentiation after 7-day treatment. Results indicated that IL-17 and bFGF differently affected SHEDs and DPSCs proliferation and clonogenicity, since bFGF increased proliferative and clonogenic potential of both cell types, while IL-17 similarly affected SHEDs, exerting no effects on adult counterparts DPSCs. In addition, both factors stimulated NANOG, OCT4, and SOX2 pluripotency markers expression in SHEDs and DPSCs showing diverse intracellular expression patterns dependent on MSCs type. As for the differentiation capacity, both factors displayed comparable effects on SHEDs and DPSCs, including stimulatory effect of IL-17 on early osteogenesis in contrast to the strong inhibitory effect showed for bFGF, while having no impact on SHEDs and DPSCs chondrogenesis. Moreover, bFGF combined with IL-17 reduced CD90 and stimulated CD73 expression on both types of MSCs, whereas each factor induced IL-6 expression indicating its' role in IL-17/bFGF-modulated properties of SHEDs and DPSCs. All these data demonstrated that dental pulp MSCs from primary and permanent teeth exert intrinsic features, providing novel evidence on how IL-17 and bFGF affect stem cell properties important for regeneration of dental pulp at different ages., (© 2021 Wiley Periodicals LLC.)

Mycoplasma pneumoniae-induced pneumonia (MPP) is a common cause of community-acquired respiratory tract infections, increasing risk of morbidity and mortality, in children. However, diagnosing early-stage MPP is difficult owing to the lack of good diagnostic methods. Here, we examined the protein profile of bronchoalveolar lavage fluid (BALF) and found that S100A8/A9 was highly expressed. Enzyme-linked immunosorbent assays used to assess protein levels in serum samples indicated that S100A8/A9 concentrations were also increased in serum obtained from children with MPP, with no change in S100A8/A9 levels in children with viral or bacterial pneumonia. In vitro, S100A8/A9 treatment significantly increased apoptosis in a human alveolar basal epithelial cell line (A549 cells). Bioinformatics analyses indicated that up-regulated S100A8/A9 proteins participated in the interleukin (IL)-17 signaling pathway. The origin of the increased S100A8/A9 was investigated in A549 cells and in neutrophils obtained from children with MPP. Treatment of neutrophils, but not of A549 cells, with IL-17A released S100A8/A9 into the culture medium. In summary, we demonstrated that S100A8/A9, possibly released from neutrophils, is a new potential biomarker for the clinical diagnosis of children MPP and involved in the development of this disease through enhancing apoptosis of alveolar basal epithelial cells., (Copyright © 2021 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

Although sex dimorphism is increasingly recognized as an important factor in pain, female-specific pain signaling is not well studied. Here we report that administration of IL-23 produces mechanical pain (mechanical allodynia) in female but not male mice, and chemotherapy-induced mechanical pain is selectively impaired in female mice lacking Il23 or Il23r. IL-23-induced pain is promoted by estrogen but suppressed by androgen, suggesting an involvement of sex hormones. IL-23 requires C-fiber nociceptors and TRPV1 to produce pain but does not directly activate nociceptor neurons. Notably, IL-23 requires IL-17A release from macrophages to evoke mechanical pain in females. Low-dose IL-17A directly activates nociceptors and induces mechanical pain only in females. Finally, deletion of estrogen receptor subunit α (ERα) in TRPV1 + nociceptors abolishes IL-23- and IL-17-induced pain in females. These findings demonstrate that the IL-23/IL-17A/TRPV1 axis regulates female-specific mechanical pain via neuro-immune interactions. Our study also reveals sex dimorphism at both immune and neuronal levels., Competing Interests: Declaration of interests R.-R.J. is a consultant of Boston Scientific and received research grant from the company. These activities are not related to this study. The other authors declare no competing interests., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Reactive astrocytes are a hallmark of neurodegenerative disease including multiple sclerosis. It is widely accepted that astrocytes may adopt alternative phenotypes depending on a combination of environmental cues and intrinsic features in a highly plastic and heterogeneous manner. However, we still lack a full understanding of signals and associated signaling pathways driving astrocyte reaction and of the mechanisms by which they drive disease. We have previously shown in the experimental autoimmune encephalomyelitis mouse model that deficiency of the molecular adaptor Rai reduces disease severity and demyelination. Moreover, using primary mouse astrocytes, we showed that Rai contributes to the generation of a pro-inflammatory central nervous system (CNS) microenvironment through the production of nitric oxide and IL-6 and by impairing CD39 activity in response to soluble factors released by encephalitogenic T cells. Here, we investigated the impact of Rai expression on astrocyte function both under basal conditions and in response to IL-17 treatment using a proteomic approach. We found that astrocytes and astrocyte-derived extracellular vesicles contain a set of proteins, to which Rai contributes, that are involved in the regulation of oligodendrocyte differentiation and myelination, nitrogen metabolism, and oxidative stress. The HIF-1α pathway and cellular energetic metabolism were the most statistically relevant molecular pathways and were related to ENOA and HSP70 dysregulation.

Platelets comprise a highly interactive immune cell subset of the circulatory system traditionally known for their unique haemostatic properties. Although platelets are considered as a vault of growth factors, cytokines and chemokines with pivotal role in vascular regeneration and angiogenesis, the exact mechanisms by which they influence vascular endothelial cells (ECs) function remain underappreciated. In the present study, we examined the role of human IL-17A/IL-17RA axis in platelet-mediated pro-angiogenic responses. We reveal that IL-17A receptor (IL-17RA) mRNA is present in platelets transcriptome and a profound increase is documented on the surface of activated platelets. By quantifying the protein levels of several factors, involved in angiogenesis, we identified that IL-17A/IL17RA axis selectively induces the release of vascular endothelial growth factor, interleukin -2 and -4, as well as monocyte chemoattractant protein -1 from treated platelets. However, IL-17A exerted no effect on the release of IL-10, an anti-inflammatory factor with potentially anti-angiogenic properties, from platelets. Treatment of human endothelial cell two-dimensional tubule networks or three-dimensional spheroid and mouse aortic ring structures with IL-17A-induced platelet releasate evoked pro-angiogenic responses of ECs. Our findings suggest that IL-17A may critically affect platelet release of pro-angiogenic factors driving ECs towards a pro-angiogenic state.

Objective: Interleukin-17 (lL-17), a pro-inflammatory cytokine produced by Th17 cells, is also considered to play an important role in bone metabolism, but the exact mechanism of bone destruction remains unclear. In this study, we explored whether IL-17 could induce osteoblasts pyroptosis in vitro., Methods: The murine primary osteoblasts were isolated from the calvarial bones of mice. The proliferation of osteoblasts was evaluated by cell counting kit-8 (CCK-8) assay. The mRNA levels of NOD-like receptor family pyrin domain containing 3 (NLRP3), apoptosis associated speck like protein containing a card (ASC), caspase-1, gasdermin-D (GSDMD), IL-1β and receptor activator of nuclear factor-kappa B ligand (RANKL) were measured by real-time quantitative PCR. Pyroptosis after IL-17 treatment was evaluated by lactate dehydrogenase (LDH) Release Assay Kit and the morphological characteristics of osteoblasts were observed via Scanning Electron Microscopy (SEM). Pyroptosis associated proteins, cleaved IL-1β and RANKL were evaluated through western blot. The release of IL-1β and RANKL was measured by ELISA. In addition, calcium nodule was tested by alizarin red staining., Results: High concentration IL-17 (100 ng/mL) could affect the proliferation of osteoblasts, promote the gene expression of NLRP3, caspase-1, GSDMD, IL-1β and RANKL. In contrast to control group, osteoblasts treated with IL-17 had the appearance of numerous pores, swelling and rupture. Also, the release of LDH, IL-1β and RANKL increased in the presence of IL-17. However, inhibition of NLRP3 prevented activation of the NLRP3 inflammasome, thereby restoring osteoblasts morphology and function., Conclusion: IL-17 induced osteoblasts pyroptosis, and the pyroptosis of osteoblasts may prompt the release of IL-1β and RANKL,which may further contribute to disruption of bone metabolism. Besides, the NLRP3 inflammasome pathway was involved in the pyroptosis of osteoblasts., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Oral tongue squamous cell carcinoma (OTSCC) is one of the most common cancers worldwide and is characterized by early metastasis and poor prognosis. Recently, we reported that extracellular interleukin-17F (IL-17F) correlates with better disease-specific survival in OTSCC patients and has promising anticancer effects in vitro. Vasculogenic mimicry (VM) is the formation of an alternative vasculogenic system by aggressive tumor cells, which is implicated in treatment failure and poor survival of cancer patients. We sought to confirm the formation of VM in OTSCC and to investigate the effect of IL-17F on VM formation. Here, we showed that highly invasive OTSCC cells (HSC-3 and SAS) form tube-like VM on Matrigel similar to those formed by human umbilical vein endothelial cells. Interestingly, the less invasive cells (SCC-25) did not form any VM structures. Droplet-digital PCR, FACS, and immunofluorescence staining revealed the presence of CD31 mRNA and protein in OTSCC cells. Additionally, in a mouse orthotopic model, HSC-3 cells expressed VE-cadherin (CD144) but lacked Von Willebrand Factor. We identified different patterns of VM structures in patient samples and in an orthotopic OTSCC mouse model. Similar to the effect produced by the antiangiogenic drug sorafenib, IL-17F inhibited the formation of VM structures in vitro by HSC-3 and reduced almost all VM-related parameters. In conclusion, our findings indicate the presence of VM in OTSCC and the antitumorigenic effect of IL-17F through its effect on the VM. Therefore, targeting IL-17F or its regulatory pathways may lead to promising therapeutic strategies in patients with OTSCC., (© 2021 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.)

Background: Interleukin (IL)-17A possesses biological activities to promote vascular endothelial cell migration and microvessel development., Objective: To clarify which angiogenic factors are involved in IL-17A-modified angiogenesis-related functions of vascular endothelial cell migration and microtube development or not., Methods: The potential contribution of various angiogenic stimulators to in vitro angiogenic activities of IL-17A was assessed with both modified Boyden Chemotaxicell chamber assay and in vitro angiogenesis assay., Results: The addition of a neutralizing antibody (Ab) for hepatocyte growth factor (HGF), basic fibroblast growth factor (bFGF) or vascular endothelial growth factor (VEGF)-A to the upper and lower compartments in a modified Boyden Chemotaxicell chamber significantly attenuated human dermal microvascular endothelial cell (HMVEC) migration elicited by IL-17A. Moreover, IL-17A-induced capillary-like microvessel development in human umbilical vein endothelial cell (HUVEC) and human dermal fibroblast (HDF) co-culture system was significantly impaired by a neutralizing Ab against HGF, bFGF, VEGF-A, cysteine-x-cysteine ligand 8 (CXCL8)/IL-8 or cysteine-x-cysteine (CXC) chemokine receptor (CXCR)-2., Conclusion: Our findings demonstrate the involvement of HGF, bFGF, VEGF-A and/or CXCL8/IL-8, to various degrees, in migration and microvessel development of vascular endothelial cells mediated by IL-17A.

Preeclampsia affects 5-8% of pregnancies and is characterized by hypertension, placental ischemia, neurological impairment, and an increase in circulating inflammatory cytokines, including Interleukin-17 (IL17). While placental ischemia has also been shown to impair cerebrovascular function, it is not known which placental-associated factor(s) drive this effect. The purpose of this study was to examine the effects of IL17 on cerebrovascular function during pregnancy. To achieve this goal, pregnant rats were infused with either IL17 (150 pg/day, 5 days, osmotic minipump), or vehicle (saline/0.7% BSA osmotic minipump) starting at gestational day (GD) 14. On GD 19, the cerebral blood flow (CBF) response to increases in mean arterial pressure (MAP) was measured in vivo, and myogenic constrictor responses of the middle cerebral artery (MCA) were assessed ex vivo. IL17 increased MAP but impaired CBF responses only at the highest arterial pressure measured (190 mmHg). Myogenic constrictor responses overall were mostly unaffected by IL17 infusion; however, the intraluminal pressure at which peak myogenic tone was generated was lower in the IL17 infused group (120 vs 165 mm Hg), suggesting maximal tone is exerted at lower intraluminal pressures in IL17-treated pregnant rats. Consistent with the lack of substantial change in overall myogenic responsiveness, there was no difference in cerebral vessel expression of putative mechanosensitive protein βENaC, but a tendency towards a decrease in ASIC2 (p = 0.067) in IL17 rats. This study suggests that infusion of IL17 independent of other placental ischemia-associated factors is insufficient to recapitulate the features of impaired cerebrovascular function during placental ischemia. Further studies to examine of the role of other pro-inflammatory cytokines, individually or a combination, are necessary to determine mechanisms of cerebral vascular dysfunction during preeclampsia., (Copyright © 2021. Published by Elsevier B.V.)

Increased interleukin (IL)-17A has been identified in joints affected by osteoarthritis (OA), but it is unclear how IL-17A, and its family members IL-17AF and IL-17F, can contribute to human OA pathophysiology. Therefore, we aimed to evaluate the gene expression and signalling pathway activation effects of the different IL-17 family members in chondrocytes and synovial fibroblasts derived from cartilage and synovium of patients with end-stage knee OA. Immunohistochemistry staining confirmed that IL-17 receptor A (IL-17RA) and IL-17RC are expressed in end-stage OA-derived cartilage and synovium. Chondrocytes and synovial fibroblasts derived from end-stage OA patients were treated with IL-17A, IL-17AF, or IL-17F, and gene expression was assessed with bulk RNA-Seq. Hallmark pathway analysis showed that IL-17 cytokines regulated several OA pathophysiology-related pathways including immune-, angiogenesis-, and complement-pathways in both chondrocytes and synovial fibroblasts derived from end-stage OA patients. While overall IL-17A induced the strongest transcriptional response, followed by IL-17AF and IL-17F, not all genes followed this pattern. Disease-Gene Network analysis revealed that IL-17A-related changes in gene expression in these cells are associated with experimental arthritis, knee arthritis, and musculoskeletal disease gene-sets. Western blot analysis confirmed that IL-17A significantly activates p38 and p65 NF-κB. Incubation of chondrocytes and synovial fibroblasts with anti-IL-17A monoclonal antibody secukinumab significantly inhibited IL-17A-induced gene expression. In conclusion, the association of IL-17-induced transcriptional changes with arthritic gene-sets supports a role for IL-17A in OA pathophysiology. Future studies should further investigate the role of IL-17A in the OA joint to establish whether anti-IL-17 treatment could be a potential therapeutic option in OA patients with an inflammatory phenotype., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Mimpen, Baldwin, Cribbs, Philpott, Carr, Dakin and Snelling.)

Ischemia or hemorrhagic stroke is one of the leading causes of death and permanent disability in the worldwide population. As a consequence of the potential increasing in stroke, stem cell therapy is currently an area of intense focus. However, there are less data available regarding the promotion of healing efficacy after stroke. The present study aimed to investigate whether the cytokine interleukin-17A (IL-17A) could have a role in promoting the neuronal differentiation of mesenchymal stem cells (MSCs) and to investigate the associated molecular mechanism. Firstly, different concentration of IL-17A at range from 5-40 ng/mL was applied to stimulate bone marrow MSCs (BMSCs) during the course of neurogenic differentiation. Then reverse transcription-PCR, histological analyses and immunofluorescence assays were used to determine the optimum concentration of IL-17A in promoting the neuronal differentiation of BMSCs, which was 20 ng/mL. Mechanistically, Wnt signaling pathway was activated and Notch signaling pathway was suppressed. In addition, there were antergic effect of these two signaling pathways modulating the neurogenic differentiation of BMSCs induced by IL-17A. The present study demonstrated the potential role of IL-17A-based BMSCs strategy for promoting neuronal differentiation in vitro. However, the treatment efficacy could be considerably confirmed in animals with ischemia stroke. Therefore, a more sophisticated strategy that addresses the complicated treatment associated with stroke is needed., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

N -Glycosylation represents an essential type of posttranslational modification for proteins. However, deciphering the functions of N -glycosylation remains a challenge due to the lack of analytical and biochemical methods to accurately differentiate the protein glycoforms with various intact glycans. Here we report our synthesis and evaluation of homogeneously glycosylated interleukin-17A (IL-17A), based on a synthetic approach combining solid-phase synthesis of (glyco)peptides, chemoenzymatic glycan modification on segments, and chemical ligations. The obtained homogeneous glycoproteins allow for the demonstration of the stabilizing role of N -glycans during the folding step. A comparison of three IL-17A glycoforms in a normal human dermal fibroblast (NHDF) assay reveals dose-dependent interleukin-6-inducing activities in all cases, wherein the glycoform with sialyl undecasaccharides displays much weaker stimulatory effect than that of the GlcNAc- or GlcNAc(β 1→4 )GlcNAc-modified proteins. Further surface plasmon resonance (SPR) and hydrogen/deuterium exchange mass spectroscopic experiments confirm that the evaluated complex type N -glycan impedes the binding between IL-17A and its receptor IL-17RA. This structure-activity relationship study on glycoproteins highlights the viability of applying the de novo approach to probe the roles of N -glycans.

Objective: The spondylarthritides (SpA) are intimately linked to new bone formation and IL-17A and TNF pathways. We investigated spinal soft tissue and bone mesenchymal stem cell (MSC) responses to IL-17A and TNF, including their osteogenesis, adipogenesis, and stromal supportive function and ability to support lymphocyte recruitment., Methods: Normal spinal peri-entheseal bone (PEB) and entheseal soft tissue (EST) were characterized for MSCs by immunophenotypic, osteogenic, chondrogenic, and adipogenic differentiation criteria. Functional and gene transcriptomic analysis was carried out on undifferentiated, adipo- differentiated, and osteo-differentiated MSCs. The enthesis C-C Motif Chemokine Ligand 20-C-C Motif Chemokine Receptor 6 (CCL20-CCR6) axis was investigated at transcript and protein levels to ascertain whether entheseal MSCs influence local immune cell populations., Results: Cultured MSCs from both PEB and EST displayed a tri-lineage differentiation ability. EST MSCs exhibited 4.9-fold greater adipogenesis ( p < 0.001) and a 3-fold lower osteogenic capacity ( p < 0.05). IL-17A induced greater osteogenesis in PEB MSCs compared to EST MSCs. IL-17A suppressed adipogenic differentiation, with a significant decrease in fatty acid-binding protein 4 ( FABP4 ), peroxisome proliferator-activated receptor gamma ( PPARγ ), Cell Death Inducing DFFA Like Effector C ( CIDEC ), and Perilipin-1 ( PLIN1 ). IL-17A significantly increased the CCL20 transcript ( p < 0.01) and protein expression ( p < 0.001) in MSCs supporting a role in type 17 lymphocyte recruitment., Conclusions: Normal spinal enthesis harbors resident MSCs with different in vitro functionalities in bone and soft tissue, especially in response to IL-17A, which enhanced osteogenesis and CCL20 production and reduced adipogenesis compared to unstimulated MSCs. This MSC-stromal-enthesis immune system may be a hitherto unappreciated mechanism of "fine tuning" tissue repair responses at the enthesis in health and could be relevant for SpA understanding.

Otitis media (OM) is a common inflammatory disease of the middle ear cavity and mainly occurs in children. As a critical regulator of inflammation response, the nuclear factor kappa B (NF- κ B) pathway has been found to play an essential role in the pathogenesis of various human diseases. The aim of this study was to explore the potential mechanism under the inflammatory response of human middle ear epithelial cells (HMEECs). We established in vitro models of OM by treating HMEECs with lipopolysaccharide (LPS) or interleukin 17A (IL-17A). Enzyme-linked immunosorbent assay and western blot analysis were used to measure the inflammatory response of HMEECs under LPS or IL-17A stimulation. The results revealed that the concentrations of proinflammatory cytokines ( p < 0.001) and protein levels of mucin (MUC) (for MUC5AC, p = 0.002, p = 0.004; for MUC8, p = 0.004, p < 0.001) were significantly elevated by LPS or IL-17A stimulation in HMEECs. Moreover, we found that LPS or IL-17A treatment promoted the phosphorylation of I κ B α (for p-I κ B α , p = 0.018, p = 0.002; for I κ B α , p = 0.238, p = 0.057) and the translocation of p65 from cytoplasm to nucleus in HMEECs (for nucleus p65, p = 0.01; for cytoplasm p65, p < 0.001). In addition, RT-qPCR analysis revealed that long noncoding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) was verified to be upregulated in LPS- or IL-17A-stimulated HMEECs ( p < 0.001). Western blot analysis and immunofluorescence staining assay revealed that that MALAT1 knockdown significantly suppressed the activation of the NF- κ B pathway by reducing phosphorylated I κ B α levels and inhibiting the nuclear translocation of p65 ( p < 0.001) in LPS- or IL-17A-stimulated HMEECs (for p-I κ B α , p < 0.001; for I κ B α , p = 0.242, p = 0.647). Silence of MALAT1 decreased the proinflammatory cytokine production and MUC protein levels ( p < 0.001). Furthermore, rescue assays revealed that the increase of proinflammatory cytokine production (for TNF- α , p = 0.002, p = 0.015; for IL-1 β , p < 0.001, p = 0.006; for IL-6, p = 0.002, p < 0.001) and MUC protein levels (for MUC5AC, p = 0.001, p < 0.001; for MUC8, p < 0.001, p = 0.001) induced by MALAT1 overexpression was neutralized by 4-N-[2-(4-phenoxyphenyl) ethyl] quinazoline-4, 6-diamine (QNZ) treatment in LPS- or IL-17A-stimulated HMEECs. In conclusion, MALAT1 promotes inflammatory response in LPS- or IL-17A- stimulated HMEECs via the NF- κ B signaling pathway, which may provide a potential novel insight for the treatment of OM., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2021 Xiangru Yang et al.)

Purpose: Emerging evidence has shown that interleukin (IL)-17A is implicated in the pathogenesis of allergic rhinitis (AR). Thymic stromal lymphopoietin (TSLP) orchestrates the immune response toward a Th2 phenotype. Although increased TSLP is found in AR, the contribution of IL-17A in TSLP production by nasal fibroblasts is not well understood. We aimed to investigate the effect and mechanism of IL-17A on TSLP production by human nasal fibroblasts (HNFs) from AR patients., Methods: HNFs from AR patients were cultured and stimulated with IL-17A in the absence or presence of a Janus kinase (JAK) 2 or JAK1/3 inhibitor. Western blotting was used to assay phosphorylated signal transducer and activator of transcription 3 (p-STAT3) and nuclear factor-kappa B (NF-κB) p65 in HNFs. The TSLP expression in the cells and culture supernatants was evaluated by real-time polymerase chain reaction and enzyme-linked immunoassay., Results: Stimulation with IL-17A induced STAT3 phosphorylation, which was inhibited by the pretreatment with JAK2 inhibitor AZD1480 or JAK1/3 inhibitor tofacitinib. IL-17A promoted the nuclear translocation of NF-κBp65 protein, leading to increased TSLP production, while the pre-incubation with AZD1480 prior to IL-17A attenuated these effects. However, the pre-incubation with tofacitinib before IL-17A stimulation had no impact on the expression of NF-κBp65 and TSLP., Conclusions: IL-17A up-regulated TSLP production by HNFs through JAK2/NF-κB pathway. Although IL-17A induced STAT3 activation through JAK1/2/3, IL-17A-mediated TSLP expression was not dependent on STAT3 signaling. These observations would provide mechanistic insight into therapeutic strategies to improve the immune and inflammation associated with Th17A in the management of AR.

Objective: To investigate the role of IL-17A in promoting the activation of lung fibroblasts and the secretion of chemokine CXCL12, and to explore the possible mechanism., Methods: Lung tissues of BALB/c mice were collected after intraperitoneal injection of recombinant mouse IL-17A (rmIL-17A). Real-time RT-PCR and Western blotting were used to detect the expression levels of α-smooth muscle actin (α-SMA) and collagen I in lung tissues, and immunohistochemical staining and real-time RT-PCR were used to determine the expression of CXCL12. Normal mouse primary lung fibroblasts were isolated and cultured, and identified by immunofluorescence staining with optical microscopy. Cells and supernatant of culture medium were collected after stimulation with rmIL-17A at different concentrations. mRNA levels of α-SMA, collagen I, and CXCL12 in the cells were determined by real-time RT-PCR, and the levels of collagen I and CXCL12 in the supernatant of culture medium were determined by ELISA., Results: The mRNA and protein levels of α-SMA and collagen I in the lung tissue of mice injected with rmIL-17A were significantly increased compared with the control group (all P <0.01). The mRNA levels of α-SMA, collagen I and CXCL12 in mice primary lung fibroblasts were increased after stimulation of rmIL-17A at different concentrations (all P <0.01), and the concentration of collagen Ⅰ and CXCL12 in the supernatants of culture medium were also increased in a dose-dependent manner (all P <0.01)., Conclusions: s: IL-17A can promote the activation of lung fibroblasts and translation into myofibroblast. The secretion of collagen is increased, which promote the deposition of extracullular matrix, and leads to the occurrence and development of lung fibrosis. CXCL12, a chemokine secreted by activated fibroblasts, may be involved in this process.