Network pharmacology analysis and experimental validation of Xiao-Qing-Long-Tang's therapeutic effects against neutrophilic asthma

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.

[Effect of LAG3 deficiency on natural killer cell function and hepatic fibrosis in mice infected with Echinococcus multilocularis]

OBJECTIVE

To investigate the effect of LAG-3 deficiency (LAG3-/-) on natural killer (NK) cell function and hepatic fibrosis in mice infected with Echinococcus multilocularis.

METHODS

C57BL/6 mice, each weighing (20 ± 2) g, were divided into the LAG3-/- and wild type (WT) groups, and each mouse in both groups was inoculated with 3 000 E. multilocularis protoscoleces via the hepatic portal vein. Mouse liver and spleen specimens were collected 12 weeks post-infection, sectioned and stained with sirius red, and the hepatic lesions and fibrosis were observed. Mouse hepatic and splenic lymphocytes were isolated, and flow cytometry was performed to detect the proportions of hepatic and splenic NK cells, the expression of CD44, CD25 and CD69 molecules on NK cell surface, and the secretion of interferon γ (IFN-γ), tumor necrosis factor α (TNF-α), interleukin (IL)-4, IL-10 and IL-17A.

RESULTS

Sirius red staining showed widening of inflammatory cell bands and hyperplasia of fibrotic connective tissues around mouse hepatic lesions, as well as increased deposition of collagen fibers in the LAG3-/-group relative to the WT group. Flow cytometry revealed lower proportions of mouse hepatic (6.29% ± 1.06% vs. 11.91% ± 1.85%, P < 0.000 1) and splenic NK cells (4.44% ± 1.22% vs. 5.85% ± 1.10%, P > 0.05) in the LAG3-/- group than in the WT group, and the mean fluorescence intensity of CD44 was higher on the surface of mouse hepatic NK cells in the LAG3-/- group than in the WT group (t = -3.234, P < 0.01), while no significant differences were found in the mean fluorescence intensity of CD25 or CD69 on the surface of mouse hepaticNK cells between the LAG3-/- and WT groups (both P values > 0.05). There were significant differences between the LAG3-/- and WT groups in terms of the percentages of IFN-γ (t = -0.723, P > 0.05), TNF-α (t = -0.659, P > 0.05), IL-4 (t = -0.263, P > 0.05), IL-10 (t = -0.455, P > 0.05) or IL-17A secreted by mouse hepatic NK cells (t = 0.091, P > 0.05), and the percentage of IFN-γ secreted by mouse splenic NK cells was higher in the LAG3-/- group than in the WT group (58.40% ± 1.64% vs. 50.40% ± 4.13%; t = -4.042, P < 0.01); however, there were no significant differences between the two groups in terms of the proportions of TNF-α (t = -1.902, P > 0.05), IL-4 (t = -1.333, P > 0.05), IL-10 (t = -1.356, P > 0.05) or IL-17A secreted by mouse splenic NK cells (t = 0.529, P > 0.05).

CONCLUSIONS

During the course of E. multilocularis infections, LAG3-/- promotes high-level secretion of IFN-γ by splenic NK cells, which may participate in the reversal the immune function of NK cells, resulting in aggravation of hepatic fibrosis.

Vascular dysfunction and arterial hypertension in experimental celiac disease are mediated by gut-derived inflammation and oxidative stress

AIMS

We examined the cardiovascular effects of celiac disease (CeD) in a humanized mouse model, with a focus on vascular inflammation, endothelial dysfunction, and oxidative stress.

METHODS AND RESULTS

NOD.DQ8 mice genetically predisposed to CeD were subjected to a diet regime and oral gavage to induce the disease (gluten group vs. control). We tested vascular function, confirmed disease indicators, and evaluated inflammation and oxidative stress in various tissues. Plasma proteome profiling was also performed. CeD markers were confirmed in the gluten group, indicating increased blood pressure and impaired vascular relaxation. Pro-inflammatory genes were upregulated in this group, with increased CD11b+ myeloid cell infiltration and oxidative stress parameters observed in aortic and heart tissue. However, heart function remained unaffected. Plasma proteomics suggested the cytokine interleukin-17A (IL-17A) as a link between gut and vascular inflammation. Cardiovascular complications were reversed by adopting a gluten-free diet.

CONCLUSION

Our study sheds light in the heightened cardiovascular risk associated with active CeD, revealing a gut-to-cardiovascular inflammatory axis potentially mediated by immune cell infiltration and IL-17A. These findings augment our understanding of the link between CeD and cardiovascular disease providing clinically relevant insight into the underlying mechanism. Furthermore, our discovery that cardiovascular complications can be reversed by a gluten-free diet underscores a critical role for dietary interventions in mitigating cardiovascular risks associated with CeD.

Oleuropein Has Modulatory Effects on Systemic Lipopolysaccharide-Induced Neuroinflammation in Male Rats

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.

Effect of IL-17 on pulmonary artery smooth muscle cells and connective tissue disease-associated pulmonary arterial hypertension

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.

Fecal microbiota transplantation regulates the microbiota-gut-spinal cord axis to promote recovery after spinal cord injury

Spinal cord injury (SCI) is devastating for patients, and currently lacks effective treatments. Dysbiosis commonly occurs after SCI and has significant immunomodulatory effects, but its impact on recovery remains unclear. The current study investigated the effects and mechanisms of fecal microbiota transplantation (FMT) in SCI. FMT was administered in a rat model of SCI and spinal pathology, inflammatory cytokines, and gut microbiome composition were assessed. Flow cytometry identified a source of interleukin (IL)-17 in spinal cord tissues, and carboxyfluorescein succimidyl ester labeling tracked γδ T cell migration. In vitro coculture was used to analyze the regulatory mechanisms of γδ T cells. Seahorse analysis was used to profile dendritic cell (DC) metabolism. Here we show that FMT improved spinal pathology and dampened post-injury inflammation. It also corrected post-SCI dysbiosis, increasing levels of the beneficial bacterium Akkermansia. The therapeutic effects of FMT were mediated by IL-17 produced by γδ T cells. FMT regulated γδ T cells via DC-T regulatory cell interaction, and induced metabolic reprogramming in DCs. These findings suggest that FMT represents a promising therapeutic approach for SCI, with potential to target IL-17+ γδ T cells. Elucidating the interconnected pathways between microbiota, immunity, and the spinal cord may facilitate novel treatment strategies.

KRT6A Inhibits IL-1β-Mediated Pyroptosis of Keratinocytes via Blocking IL-17 Signaling

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.

Prostaglandin E2 promotes Th17 differentiation induces corneal epithelial cell apoptosis and participates in the progression of dry eye

This study is mainly based on T helper type 17 (Th17) cells analysis of the mechanism of prostaglandin E2 (PGE2) promoting the progression of dry eye (DE). Scopolamine and dry environment were used to induce mice DE model. Celecoxib was used to inhibit PGE2. Corneal epithelial cells and CD4+ T cells were used to construct a co-culture system. The osmotic pressure was increased by adding NaCl to simulate DE in vitro. AH6809 and E7046 were used to pre-culture to inhibit EP2/4 in T cells to verify the effect of exogenous PGE2 on Th17 cell differentiation and corneal epithelial cell apoptosis. The function of Th17 cells was analyzed by detecting RORγt and interleukin-17 (IL-17). PGE2 was instilled on the ocular surface to induce DE symptoms of mice. AH6809 and E7046 were used to inhibit EP2/4. The corneal epithelial cell apoptosis was observed by TUNEL. The proportion of Th17 cells in corneal tissue and draining lymph nodes (DLNs) was detected by flow cytometry. In DE mice, the concentration of PGE2 and IL-17 increased in tears, and the proportion of Th17 increased, while inhibition of PGE2 alleviated the symptoms of DE and inhibited Th17 differentiation. Hypertonic environment induces corneal epithelial cells to secrete PGE2. PGE2 promoted the expression of EP2/4 and the differentiation of Th17 cells in vitro. The hypertonic environment promoted PGE2 level and the apoptosis of corneal epithelial cells in the co-culture system. PGE2 alone did not cause corneal epithelial cell apoptosis, while PGE2 promoted apoptosis by promoting Th17. Blocking EP2/4 reduced the induction of Th17 differentiation by PGE2 and the promoted corneal epithelial cell apoptosis. Animal experiments showed that exogenous PGE2 induced DE symptoms. Blocking EP2/4 not only inhibited the proportion of Th17, but also alleviated the apoptosis of corneal epithelial cells caused by PGE2. PGE2 induces aggravation of inflammation by promoting the level of Th17 in the ocular surface, and causes corneal epithelial cell apoptosis, thereby participating in the progression of DE.

Transcriptomic profiling of lipopolysaccharide-challenged bovine mammary epithelial cells treated with forsythoside A

Mastitis is usually caused by a variety of pathogenic bacteria that seriously impact the health and milk-production ability of dairy cows, with consequent, economically detrimental effects on the dairy industry. Forsythoside A (FTA), isolated from the fruit and leaves of Forsythia suspensa (Thunb.) Vahl (Oleaceae), has been reported to have significant antioxidant, anti-inflammatory, and antibacterial effects. However, it is not clear whether FTA exerts a protective effect against lipopolysaccharide (LPS)-induced bovine mastitis and its potential gene signature. In this study, high-throughput sequencing technology was performed to analyze the differences between the mRNA and enrichment pathway of bovine mammary epithelial cells of the control, LPS, and LPS + FTA groups. The results showed that there were 139 differentially expressed genes (DEGs) (p-value < 0.05, |log2FoldChange| > 1, FPKM > 1) in the LPS group compared with the control group, including 121 up-regulated genes and 18 down-regulated genes, which were mainly enriched in the cellular response to lipopolysaccharide, cytokine activity, protein binding, and IL-17 signaling pathway based on Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, respectively. Compared with the control group and LPS + FTA group, there were 349 DEGs, including 322 up-regulated genes and 27 down-regulated genes. They were mainly enriched in protein localization to organelles, centrosomes, binding, and the IL-17 signaling pathway, based on GO and KEGG analysis. Compared to the LPS group, the LPS + FTA group had 272 DEGs, including 259 up-regulated genes and 13 down-regulated genes, which were mainly enriched in RNA processing, IL-6 receptor binding, and the lysosome pathway, based on GO and KEGG analyses. It can be seen that LPS stimulation induced the expression of inflammation-related genes, IL-17 and IL-6, whereas FTA treatment promoted the expression of the spliceosome-, lysosome-, and oxidative stress-related genes HSP70, HSPA8, and PARP2. The study utilized RNA-sequencing analysis of FTA against LPS-challenged bovine mammary epithelial cells to explore key mRNA findings that may be strongly associated with inflammation and oxidative stress, and provides a theoretical reference for further elucidation of molecular mechanisms of bovine mastitis and therapeutic effects of FTA against bovine mastitis.

Gut microbiota-derived 12-ketolithocholic acid suppresses the IL-17A secretion from colonic group 3 innate lymphoid cells to prevent the acute exacerbation of ulcerative colitis

Intestinal microbiota dysbiosis and metabolic disruption are well-known as the primary triggers of ulcerative colitis (UC). However, their role in regulating the group 3 innate lymphoid cells (ILC3s), which are essential for intestinal health, remains unexplored during the development of disease severity. Here, our results showed that the microbiota structure of patients with severe UC (SUCs) differed from those with mild UC (MiUCs), moderate UC (MoUCs), and healthy controls (HCs). Microbes producing secondary bile acids (SBAs) and SBAs decreased with the aggravation of UC, and a strong positive correlation existed between them. Next, fecal microbiota transfer was used to reproduce the human-derived microbiota in mice and decipher the microbiota-mediated inflammatory modulation during an increase in disease severity. Mice receiving SUC-derived microbiota exhibited enhancive inflammation, a lowered percentage of ILC3s, and the down-regulated expressions of bile acid receptors, including vitamin D receptor (VDR) and pregnane X receptor (PXR), in the colon. Similar to clinical results, SBA-producing microbes, deoxycholic acids (DCA), and 12-ketolithocholic acids (12-KLCA) were diminished in the intestine of these recipients. Finally, we compared the therapeutic potential of DCA and 12-KLCA in preventing colitis and the regulatory mechanisms mediated by ILC3s. 12-KLCA but not DCA represented a strong anti-inflammatory effect associated with the higher expression of VDR and the lower secretion of IL-17A from colonic ILC3s. Collectively, these findings provide new signatures for monitoring the acute deterioration of UC by targeting gut microbiota and bile acid metabolism and demonstrate the therapeutic and preventive potential of a novel microbiota-derived metabolite, 12-KLCA.

Melittin inhibits tumor cell migration and enhances cisplatin sensitivity by suppressing IL-17 signaling pathway gene LCN2 in castration-resistant prostate cancer

BACKGROUND

Melittin is a small molecule polypeptide extracted from the abdominal cavity of bees, which is used to treat inflammatory diseases and relieve pain. However, the antitumor effect of melittin and its mechanisms remain unclear, especially in castration-resistant prostate cancer (CRPC).

METHODS

Through CCK-8 assay, colony formation assay, wound healing assay and Transwell migration assay, we explored the effect of melittin on CRPC cell lines. In addition, with microarray analysis, gene ontology analysis and kyoto encyclopedia of genes and genomes analysis, this study identified key genes and signaling pathways that influence the growth of PC-3 cells. Meanwhile, the effect of melittin on CRPC was also verified through subcutaneous tumor formation experiments. Finally, we also tested the relevant indicators of human prostate cancer (PCa) specimens through immunohistochemistry and H＆E stating.

RESULTS

Here, melittin was verified to inhibit the cell proliferation and migration of CPRC. Moreover, RNA-sequence analysis demonstrated that Interleukin-17 (IL-17) signaling pathway gene Lipocalin-2 (LCN2) was downregulated by melittin treatment in CRPC. Further investigation revealed that overexpression of LCN2 was able to rescue tumor suppression and cisplatin sensitivity which melittin mediated. Interestingly, the expression of LCN2 is highly related to metastasis in PCa.

CONCLUSIONS

In brief, our study indicates that LCN2 plays an oncogenic role in CRPC and melittin may be selected as an attractive candidate for CRPC therapy.

Avian safety guardian: Luteolin restores Mycoplasma gallisepticum-induced immunocompromise to improve production performance via inhibiting the IL-17/NF-kB pathway

Mycoplasma gallisepticum (MG) is a major pathogen causing chronic respiratory disease (CRD) in chickens. Exposure to MG poses a constant threat to chicken health and causes substantial economic losses. Antibiotics are the main treatment for MG infections, but have to struggle with antibiotic residues and MG resistance. To date, no safe and more effective prevention or treatment for MG infections has been identified. Luteolin (Lut) is a natural flavonoid compound known for its excellent anti-viral, anti-bacterial, immunoregulatory, and anti-inflammatory pharmacological activities. Herein, we established an MG-infected model using partridge shank chickens and chicken-like macrophages (HD11 cells) to investigate the effect and potential mechanism of Lut against MG-induced immune damage. According to our findings, Lut significantly inhibited the expression of MG adhesion protein (pMGA1.2) in vivo and in vitro. Lut effectively mitigated the MG-induced decrease in body weight gain, feed conversion ratio, survival rate, and serum IgG and IgA levels. Lut directly repaired MG-induced spleen and thymus damage by histopathological analysis. Furthermore, network pharmacology analysis revealed that Lut most probably resisted MG infection through the IL-17/NF-kB pathway. In vivo and in vitro experiments, Lut significantly suppressed the increase in key protein IL-17A, TRAF6, p-p65, and p-IkBα in the IL-17/NF-kB pathway. Meanwhile, Lut markedly alleviated MG-induced the increase of pro-inflammatory cytokines TNF-α, IL-6, IL-1β, pro-apoptotic genes caspase3 and caspase9, while promoting the expression of anti-apoptotic genes Bcl-2 and Bcl-XL. In summary, Lut effectively suppressed MG colonization, alleviated MG-induced the production performance degradation, inflammatory responses, and immune damage by inhibiting the IL-17/ NF-kB pathway. This study indicates Lut can serve as a safe and effective antibiotic alternative drug for preventing and treating MG-induced CRD. It also provides new evidence to explore the molecular mechanisms of MG infection.

Notopterol Suppresses IL-17-Induced Proliferation and Invasion of A549 Lung Adenocarcinoma Cells via Modulation of STAT3, NF-κB, and AP-1 Activation

Interleukine-17 is a proinflammatory cytokine that promotes lung cancer growth and progression though the activation of the STAT3, NF-κB, and AP-1 signaling pathways. Therefore, blocking the IL-17-induced oncogenic pathway is a new strategy for the treatment of lung cancer. Notopterol, a furanocoumarin, has demonstrated anti-tumor effects in several types of tumors. However, its molecular function in relation to the IL-17-induced proliferation and invasion of A549 lung adenocarcinoma cells remains unknown. Here, notopterol exhibited an inhibitory effect on IL-17-promoted A549 cell proliferation and induced G0/G1 cell cycle arrest. Western blot analysis revealed that notopterol inhibited the expression of cell-cycle-regulatory proteins, including cyclin D1, cyclin E, CDK4, and E2F. Moreover, notopterol blocked IL-17-induced A549 cell migration and invasion by regulating the epithelial-mesenchymal transition (EMT) and reducing the expression of extracellular degradation enzymes. At the molecular level, notopterol treatment significantly down-regulated the IL-17-activated phosphorylation of Akt, JNK, ERK1/2, and STAT3, leading to a reduced level of transcriptional activity of NF-κB and AP-1. Collectively, our results suggest that notopterol blocks IL-17-induced A549 cell proliferation and invasion through the suppression of the MAPK, Akt, STAT3, AP-1, and NF-κB signaling pathways, as well as modulating EMT.

Enhanced Innate and Acquired Immune Responses in Systemic Sclerosis Primary Peripheral Blood Mononuclear Cells (PBMCs)

Chronic immune activation in systemic sclerosis is supported by the production of a plethora of cytokines with proven regulatory activities of the immune responses. This study aimed to explore PBMCs' cytokine profiles in SSc patients versus controls, as well as to investigate the balance between pro- and anti-inflammatory cytokines in association with disease duration. PBMCs were isolated from 18 SSc patients and 17 controls and further subjected to in vitro stimulation with lipopolysaccharide and heat-killed Candida albicans. Cytokine production was measured after 24 h and 7 days, respectively, using ELISA kits for interleukin (IL)-1β, IL-1 receptor antagonist (IL-1Ra), IL-6, tumor necrosis factor (TNF), IL-10, IL-17, and interferon-gamma (IFN-gamma). IL-1 β, IL-6, and TNF levels were increased in SSc patients compared with healthy volunteers irrespective of the stimulus used. IL-1Ra and Il-17 concentrations were not statistically different between groups, even though a trend toward higher levels in patients compared with their matched controls was also observed. Most cytokines demonstrated a stable course with disease progression, except for IL-10 levels, which declined over time. In conclusion, the results of this pilot study reveal that in patients with SSc a persistently enhanced immune response is established and maintained regardless of stimulus or disease duration.

Punicalagin alleviates the hyperproliferation of keratinocytes in psoriasis through inhibiting SKP2 expression

Psoriasis is a chronic inflammatory skin disorder characterized by abnormal keratinocytes proliferation and multiple immune cells infiltration in the dermis and epidermis. Although most psoriasis-related researches have been concentrated on the interleukin-23 (IL-23)/interleukin-17 (IL-17) axis, new data suggest that keratinocytes also play a pivotal role in psoriasis. Previously, we found that punicalagin (PUN), a bioactive ellagitannin extracted from Pericarpium Granati (the pericarpium of Punica granatum L.), exerts a therapeutic effect on psoriasis. However, the underlying mechanism, especially its potential modulatory effect on keratinocytes, remains obscure. Our study aims to reveal the potential regulatory effect and its underlying cellular mechanism of PUN on the hyperproliferation of keratinocytes. We used tumor necrosis factor α (TNF-α), IL-17A and interleukin-6 (IL-6) to induce abnormal proliferation of HaCaT cells (Human Keratinocytes Cells) in vitro. Then, we evaluated the effects of PUN through MTT assay, EdU staining and cell cycle detection. Finally, we explored the underlying cellular mechanisms of PUN via RNA-sequencing, WB in vitro and in vivo. Here, we found that PUN can directly and dose-dependently decrease TNF-α, IL-17A and IL-6-induced abnormal proliferation of HaCaT cells in vitro. Mechanically, PUN suppresses the hyperproliferation of keratinocytes through repressing S-phase kinase-associated protein 2 (SKP2) expression in vitro and in vivo. Moreover, overexpression of SKP2 can partly abolish PUN-mediated inhibition of aberrantly proliferative keratinocytes. These results illustrate that PUN can reduce the severity of psoriasis through directly repressing SKP2-mediated abnormal proliferation of keratinocytes, which gives new insight into the therapeutic mechanism of PUN on psoriasis. Moreover, these findings imply that PUN might be a promising drug candidate for the treatment of psoriasis.

Chronic treatment with IL-25 increases renal M2 macrophages and reduces renal injury in obese Dahl salt-sensitive rats during the prepubescent stage

Recently, we have reported that the early progression of proteinuria in the obese Dahl salt-sensitive (SS) leptin receptor mutant (SSLepRmutant) 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 SSLepRmutant 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 SSLepRmutant rats were treated with either control (IgG) or IL-25 (1 µg/day ip every other day) for 4 wk. The kidneys from SSLepRmutant 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 SSLepRmutant 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 SSLepRmutant strain. Although the administration of IL-25 did not change total renal macrophage infiltration in both SS and SSLepRmutant rats, IL-25 increased M2a by >50% and reduced M1 by 60% in the kidneys of SSLepRmutant rats. Overall, these data indicate that IL-25 reduces the early progression of renal injury in SSLepRmutant 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.

Aerosolized nicotine from e-cigarettes alters gene expression, increases lung protein permeability, and impairs viral clearance in murine influenza infection

E-cigarette use has rapidly increased as an alternative means of nicotine delivery by heated aerosolization. Recent studies demonstrate nicotine-containing e-cigarette aerosols can have immunosuppressive and pro-inflammatory effects, but it remains unclear how e-cigarettes and the constituents of e-liquids may impact acute lung injury and the development of acute respiratory distress syndrome caused by viral pneumonia. Therefore, in these studies, mice were exposed one hour per day over nine consecutive days to aerosol generated by the clinically-relevant tank-style Aspire Nautilus aerosolizing e-liquid containing a mixture of vegetable glycerin and propylene glycol (VG/PG) with or without nicotine. Exposure to the nicotine-containing aerosol resulted in clinically-relevant levels of plasma cotinine, a nicotine-derived metabolite, and an increase in the pro-inflammatory cytokines IL-17A, CXCL1, and MCP-1 in the distal airspaces. Following the e-cigarette exposure, mice were intranasally inoculated with influenza A virus (H1N1 PR8 strain). Exposure to aerosols generated from VG/PG with and without nicotine caused greater influenza-induced production in the distal airspaces of the pro-inflammatory cytokines IFN-γ, TNFα, IL-1β, IL-6, IL-17A, and MCP-1 at 7 days post inoculation (dpi). Compared to the aerosolized carrier VG/PG, in mice exposed to aerosolized nicotine there was a significantly lower amount of Mucin 5 subtype AC (MUC5AC) in the distal airspaces and significantly higher lung permeability to protein and viral load in lungs at 7 dpi with influenza. Additionally, nicotine caused relative downregulation of genes associated with ciliary function and fluid clearance and an increased expression of pro-inflammatory pathways at 7 dpi. These results show that (1) the e-liquid carrier VG/PG increases the pro-inflammatory immune responses to viral pneumonia and that (2) nicotine in an e-cigarette aerosol alters the transcriptomic response to pathogens, blunts host defense mechanisms, increases lung barrier permeability, and reduces viral clearance during influenza infection. In conclusion, acute exposure to aerosolized nicotine can impair clearance of viral infection and exacerbate lung injury, findings that have implications for the regulation of e-cigarette products.

IL-17A regulates autophagy and promotes osteoclast differentiation through the ERK/mTOR/Beclin1 pathway

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.

The lncRNA HOTAIR via miR-17-5p is involved in arsenite-induced hepatic fibrosis through regulation of Th17 cell differentiation

Arsenic compounds are toxins that are widely distributed in the environment. Chronic exposure to low levels of these compounds can cause hepatic fibrosis and other damage. Th17 differentiation of CD4⁺ T cells and the secretion of IL-17 activates hepatic stellate cells (HSCs), which are involved in hepatic fibrosis, but their mechanisms in arsenic-induced hepatic fibrosis are unclear. We found, in arsenite-induced fibrotic livers of mice, increases of CD4⁺ T cell infiltration, Th17 cell nuclear receptor retinoic acid receptor-related orphan receptor γt (RORγt), and secretion of the pro-inflammatory cytokine IL-17. There were also elevated levels of the lncRNA, HOTAIR. For Jurkat cells, arsenite elevated levels of HOTAIR and protein levels of RORγt and IL-17A, decreased miR-17-5p, promoted Th17 cell differentiation, and released IL-17. The culture medium of arsenite-treated Jurkat cells activated LX-2 cells. Down-regulation of HOTAIR or up-regulation of miR-17-5p blocked arsenite-induced Th17 cell differentiation, which inhibited the LX-2 cell activation. However, down-regulation of HOTAIR and miR-17-5p reversed this inhibitory effect. For mice, silencing of HOTAIR diminished the hepatic levels of RORγt and IL-17A and alleviated arsenite-induced hepatic fibrosis. These results demonstrate that, for CD4⁺ T cells, arsenite promotes RORγt-mediated Th17 cell differentiation through HOTAIR down-regulation of miR-17-5p, and increases the secretion of cytokine IL-17A, which activates HSCs; the activated HSCs facilitate hepatic fibrosis. The findings reveal a new mechanism and a potential therapeutic target for arsenite-induced hepatic fibrosis.

Silence of S1PR4 Represses the Activation of Fibroblast-like Synoviocytes by Regulating IL-17/STAT3 Signaling Pathway

Rheumatoid arthritis (RA) is a chronic inflammatory disease with persistent inflammation and progressive joint damage. However, the underlying pathological mechanisms of RA are still unclear. Fibroblast‑like synoviocytes (FLSs) play an important role in the pathogenesis of RA by the regulation of proliferation and apoptosis, and the release of multiple pro-inflammatory factors. The lipid mediator sphingosine-1-phosphate receptor 4 (S1PR4) is one of the sphingolipid sphingosine-1-phosphate (S1P) receptors, which affects the function of immune cells. However, the role of S1PR4 in the activation of FLSs and the development of RA is unknown. In this study, we found that the expression of S1PR4 was significantly increased in RA-FLSs. The silence of S1PR4 decreases the proliferation, migration, proinflammation, and promotes the apoptosis of RA-FLSs, accompanied with repressing interleukin-17 (IL-17)/signal transducer and activator of transcription 3 (STAT3) signal pathway. However, the regulatory effects of S1PR4 silencing on RA-FLSs were partly abolished by additional recombinant human (rh) IL-17A treatment. Therefore, our study demonstrated that S1PR4 silencing might inhibit proliferation, migration, proinflammation, and promote apoptosis of RA-FLSs partly by repressing IL-17, which suggests that inhibitors for S1PR4 might be a potentially promising strategy for the treatment of RA.

[Effect of dragon's blood extract on periodontal tissue repair and TLR4/NF-κB signal pathway]

PURPOSE

To discuss the effects of dragon's blood extract, a Chinese herb, on periodontal tissue repair and toll like receptor 4/nuclear transcription factor kappa B(TLR4/NF-κB) in gingivitis rats.

METHODS

Sixty rats were randomly divided into control group, gingivitis group and low, medium and high dose groups of dragon's blood extract, with 10 rats in each group. Except the control group, the gingivitis rat model was established by silk thread ligation in other groups. The model was established successfully. The low, medium and high dose groups rats were given 150, 300 and 600 mg·kg^-1·d^-1 dragon's blood extract successively by gavage (once a day for 4 weeks). Rats in the model group and the control group were given the same amount of normal saline by gavage at the same time. After the rats were sacrificed under anesthesia, the jaw tissue of the left maxillary second molar was stained with methylene blue to observe and measure the loss of alveolar bone (ABL), H-E staining was used to observe the pathological changes of periodontal tissue (jaw tissue). The levels of IL-17 and IL-4 in periodontal tissue (jaw tissue) of rats in each group were detected by enzyme-linked immunosorbent assay (ELISA). Bone morphogenetic protein-2(BMP-2), TLR4 and NF-κB p65 protein level in rat periodontal tissue were detected by Western blot. SPSS 19.0 software package was used to analyze the data.

RESULTS

Compared with the control group, IL-17, IL-4, TLR4 and NF-κB p65 protein and ABL in jaw tissue of model group were significantly increased (P＜0.05), and the level of BMP-2 protein in jaw tissue significantly decreased (P＜0.05). Compared with the model group, IL-17, IL-4, TLR4 and NF-κB p65 protein and ABL in jaw tissue of rats in low, medium and high dose groups of dragon's blood extract were significantly increased, and the level of BMP-2 protein significantly decreased(P＜0.05).

CONCLUSIONS

Dragon's blood extract can inhibit TLR4/NF- κB. Activation of B pathway inhibits inflammatory response and promotes periodontal tissue repair in gingivitis rats.

VR-10 polypeptide interacts with CD36 to induce cell apoptosis and autophagy in choroid-retinal endothelial cells: Identification of VR-10 as putative novel therapeutic agent for choroid neovascularization (CNV) treatment

Choroid neovascularization (CNV) is important adverse pathological changes that contributes to the aggravation of hypoxic-ischemic eye diseases, and our preliminary work evidences that the thrombospondin-1 (TSP-1) synthetic polypeptide VR-10 may be the candidate therapeutic agent for the treatment of CNV, but its detailed effects and molecular mechanisms are not fully delineated. In this study, the CNV models in BN rats were established by using the laser photocoagulation method, which were further subjected to VR-10 peptide treatment. The RNA-seq and bioinformatics analysis suggested that VR-10 peptide significantly altered the expression patterns of genes in the rat ocular tissues, and the changed genes were especially enriched in the CD36-associated signal pathways. Next, by performing the Real-Time qPCR and Western Blot analysis, we expectedly found that VR-10 upregulated the anti-angiogenesis biomarker (PEDF) and downregulated pro-angiogenesis biomarkers (VEGF, HIF-1 and IL-17) in rat tissues. In addition, we evidenced that VR-10 downregulated CDK2, CDK4, CDK6, Cyclin D1 and Cyclin D2 to induce cell cycle arrest, upregulated cleaved Caspase-3, Bax and downregulated Bcl-2 to promote cell apoptosis, and increased LC3B-II/I ratio and facilitate p62 degradation to promote cell autophagy in RF/6A cells, which were all reversed by knocking down CD36. Moreover, VR-10 upregulated PEDF, and decreased the expression levels of VEGF, HIF-1 and IL-17 to block angiogenesis of RF/6A cells in a CD36-dependent manner. Taken together, VR-10 peptide interacts with its receptor CD36 to regulate the biological functions of RF/6A cells, and these data suggest that VR-10 peptide may be the putative therapeutic drug for the treatment of CNV in clinic.

The Effects of Combuxil and Leizumab on Retinal Function and Serum Interleukin-17A in Premature Infants with Retinopathy

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.

Effects of Boric Acid Gel on Vaginal Candida albicans Infections and the Local Immune System in Mice

The objective was to determine the effect of 5% boric acid gel on vaginal Candida albicans (CA) infections in mice and its effect on the local immune system (i.e., Th1, Th2, and Th17). Female mice were divided into four groups, with 10 mice in each group. Mycelial suspensions were administered into the vaginal lumen close to the cervix in groups B, F, and M. Mice in group B were given boric acid gel, and group F was treated with fluconazole gel for 30 min every 12 h. Group M was treated with sterile water, and group N was not given treatment. After the seventh day of treatment, each group was observed with the naked eye, and vaginal lavage fluid and vaginal tissue were collected. Expression levels of cytokines were measured using enzyme-linked immunosorbent assays (ELISA) and immunohistochemistry. Periodic acid Schiff (PAS) staining was used to measure the fungi in vaginal tissues. There were no significant changes in group M. In groups B and F, there was less vaginal injury and less exudate, with group B doing better than group F. The numbers of CA colonies were higher in groups B, F, and M than in group N (P < 0.01). There was less vaginal colonization of CA in group B than in group F (P < 0.01). After the seventh day of treatment, levels of IFN-γ, IL-17, IL-6, TGF-β, IL-4, and IL-10 were significantly greater in groups B, F, and M than in group N (P < 0.001); levels of IFN-γ, IL-17, IL-6, and TGF-β in groups B and F were higher than those of group M (P < 0.01), while IL-4 and IL-10 levels were significantly lower (P < 0.001). The trends of cytokine increases and decreases were more significant in group B than in group F (P < 0.05). Immunohistochemical results were similar to ELISA results. PAS staining revealed that boric acid inhibited hyphal reproduction. The boric acid significantly reduced the symptoms associated with CA vaginal infection. It inhibited the CA growth, prevented vaginal lesions, promoted the secretion of Th1 and Th17 cytokines, and reduced Th2 cytokines.

Human IL-17 and TNF-α Additively or Synergistically Regulate the Expression of Proinflammatory Genes, Coagulation-Related Genes, and Tight Junction Genes in Porcine Aortic Endothelial Cells

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.

[miR-328-3p down-regulates FOXP3 to inhibit IL-17-induced invasion and migration of Caco-2 human colorectal cancer cells]

Objective To investigate the effect of miR-328-3p on the invasion and migration of colorectal cancer cells induced by interleukin-17 (IL-17) and its mechanism. Methods Real-time quantitative PCR was used to detect the expressions of miR-328-3p, FOXP3, and IL-17 mRNA in FHC colorectal epithelial cells and colorectal cancer cells (HCT116, Caco-2, and LoVo). Transwell^TM assay was used to detect cell invasion and migration, and gelatin zymography assay to detect the activities of matrix metalloproteinases 2 (MMP2) and MMP9. Dual luciferase reporter assay was conducted to detect the targeted regulation relationship between miR-328-3p and FOXP3. The level of FOXP3 protein in Caco-2 cells was detected by Western blot analysis. Results Compared with those in colorectal epithelial cells, the expression level of miR-328-3p in colorectal cancer cells decreased, while the levels of FOXP3 and IL-17 increased. Transfection of miR-328-3p mimics inhibited the invasion and migration ability of IL-17-induced Caco-2 cells and the activities of MMP2 and MMP9 in the cells. miR-328-3p directly targeted and inhibited the protein level of FOXP3 in Caco-2 cells. Overexpression of FOXP3 partly reversed the effect of miR-328-3p mimics on the invasion and migration ability of IL-17-induced Caco-2 cells and the activities of MMP2 and MMP9 in the cells. Conclusion miR-328-3p inhibits the invasion and migration of IL-17-induced Caco-2 cells by down-regulating FOXP3.

A Recombinant Dimethylarginine Dimethylaminohydrolase-1-Based Biotherapeutics to Pharmacologically Lower Asymmetric Dimethyl Arginine, thus Improving Postischemic Cardiac Function and Cardiomyocyte Mitochondrial Activity

High serum levels of asymmetric dimethyl arginine (ADMA) are associated with cardiovascular disease and mortality. Pharmacological agents to specifically lower ADMA and their potential impact on cardiovascular complications are not known. In this study, we aimed to investigate the effect of specific lowering of ADMA on myocardial response to ischemia-reperfusion injury (I/R) and direct effects on cardiomyocyte function. Effects of recombinant dimethylarginine dimethylaminohydrolase (rDDAH)-1 on I/R injury were determined using isolated mouse heart preparation. Respiration capacity and mitochondrial reactive oxygen species (ROS) generation were determined on mouse cardiomyocytes. Our results show that lowering ADMA by rDDAH-1 treatment resulted in improved recovery of cardiac function and reduction in myocardial infarct size in mouse heart response to I/R injury (control 22.24 ±4.60% versus rDDAH-1 15.90 ±4.23%, P < 0.01). In mouse cardiomyocytes, rDDAH-1 treatment improved ADMA-induced dysregulation of respiration capacity and decreased mitochondrial ROS. Furthermore, in human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes with impaired contractility under hypoxia and high ADMA, rDDAH-1 treatment improved recovery and beating frequency (P < 0.05). rDDAH-1 treatment selectively modified I/R-induced myocardial cytokine expression, resulting in reduction in proinflammatory cytokine IL-17A (P < 0.001) and increased expression of anti-inflammatory cytokines IL-10 and IL-13 (P < 0.01). Further in vitro studies showed that IL-17A was the predominant and common cytokine modulated by ADMA-DDAH pathway in heart, cardiomyocytes, and endothelial cells. These studies show that lowering ADMA by pharmacological treatment with rDDAH-1 reduced I/R injury, improved cardiac function, and ameliorated cardiomyocyte bioenergetics and beating activity. These effects may be attributable to ADMA lowering in cardiomyocytes and preservation of cardiomyocyte mitochondrial function. SIGNIFICANCE STATEMENT: The pathological role of asymmetric dimethyl arginine (ADMA) has been demonstrated by its association with cardiovascular disease and mortality. Currently, pharmacological drugs to specifically lower ADMA are not available. The present study provides the first evidence that lowering of ADMA by recombinant recombinant dimethylarginine dimethylaminohydrolase (rDDAH)-1 improved postischemic cardiac function and cardiomyocyte bioenergetics and beating activity. Our studies suggest that lowering of ADMA by pharmacologic treatment offers opportunity to develop new therapies for the treatment of cardiovascular and renal disease.

Hypoxia-Inducible Factor-2 Alpha Regulates the Migration of Fibroblast-like Synoviocytes via Oxidative Stress-Induced CD70 Expression in Patients with Rheumatoid Arthritis

This study aimed to examine the role of CD70, which is highly expressed on fibroblast-like synoviocytes (FLS), in rheumatoid arthritis (RA) patients. FLS isolated from RA (n = 14) and osteoarthritis (OA, n = 4) patients were stimulated with recombinant interleukin-17 (IL-17; 5 ng/mL) and tumor necrosis factor alpha (TNF-α; 5 ng/mL) for 24 h. Expression of CD70, CD27/soluble CD27 (sCD27), and hypoxia-inducible factor-2 alpha (HIF-2α) was analyzed by RT-qPCR, flow cytometry, and ELISA assays, respectively. Reactive oxygen species (ROS) expression and cell migration were also examined. The HIF-2α inhibitor PT-2385 and CD70 inhibitor BU69 were used to specifically suppress these pathways. Stimulation with IL-17 and TNF-α significantly induced CD70 expression in RA FLS. Although the synovial fluids from patients with RA contained high levels of sCD27, surface expression of CD27, a ligand of CD70, was rarely detected in RA FLS. Cytokine-induced CD70 expression was significantly decreased following antioxidant treatment. Following HIF-2α inhibition, RA FLS had decreased expression of CD70 and ROS levels. Migration of RA FLS was also inhibited by inhibition of CD70 or HIF-2α. The surface expression of CD70 is regulated by HIF-2α and ROS levels and is a key contributor to cytokine-enhanced migration in RA FLS.

Profilin-1 prevents psoriasis pathogenesis through IκBζ regulation

Profilin-1 (PFN-1) is an actin-binding protein that regulates actin polymerization, cell proliferation, apoptosis, angiogenesis, and carcinogenesis. Its dysregulation has been reported in diverse pathologic diseases; however, the role of PFN-1 in psoriasis has not yet been elucidated. In this study, we demonstrate that PFN-1 expression is increased in both skin and serum of patients with psoriasis. PFN-1 was markedly expressed in the epidermis of psoriatic lesions and its expression positively correlated with psoriasis severity. IL-17A treatment of keratinocytes increased the PFN-1 expression, whereas TNF-α induced the PFN-1 expression and secretion. In addition, knockdown of PFN-1 with shRNA resulted in an altered expression of psoriasis-associated inflammatory markers, HBD-2, S100A7, S100A9, and Ki67, and recombinant PFN-1 suppressed the IL-17A-induced inflammatory response in keratinocytes. Interestingly, recombinant PFN-1 also suppressed IL-17A-induced IκBζ, an important player in immune response in psoriasis. Collectively, our results show that PFN-1 acts as a negative regulator of psoriatic inflammation through suppression of IκBζ, and the balanced level of PFN-1 is important for the IκBζ regulation. Thus, the expression of PFN-1 can be used as a biomarker for psoriasis severity, and it can be considered as a possible target for the treatment of psoriasis.

IL-17RA-signaling in Lgr5+ intestinal stem cells induces expression of transcription factor ATOH1 to promote secretory cell lineage commitment

The Th17 cell-lineage-defining cytokine IL-17A contributes to host defense and inflammatory disease by coordinating multicellular immune responses. The IL-17 receptor (IL-17RA) is expressed by diverse intestinal cell types, and therapies targeting IL-17A induce adverse intestinal events, suggesting additional tissue-specific functions. Here, we used multiple conditional deletion models to identify a role for IL-17A in secretory epithelial cell differentiation in the gut. Paneth, tuft, goblet, and enteroendocrine cell numbers were dependent on IL-17A-mediated induction of the transcription factor ATOH1 in Lgr5+ intestinal epithelial stem cells. Although dispensable at steady state, IL-17RA signaling in ATOH1+ cells was required to regenerate secretory cells following injury. Finally, IL-17A stimulation of human-derived intestinal organoids that were locked into a cystic immature state induced ATOH1 expression and rescued secretory cell differentiation. Our data suggest that the cross talk between immune cells and stem cells regulates secretory cell lineage commitment and the integrity of the mucosa.

Interleukin-17 promotes proliferation, migration, and invasion of trophoblasts via regulating PPAR-γ/RXR-α/Wnt signaling

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.

The attenuation of Th1 and Th17 responses via autophagy protects against methicillin-resistant Staphylococcus aureus-induced sepsis

Whether autophagy affects methicillin-resistant Staphylococcus aureus (MRSA)-induced sepsis and the associated mechanisms are largely unknown. This study investigated the role of autophagy in MRSA-induced sepsis. The levels of microtubule-associated protein light chain 3 (LC3)-II/I, Beclin-1 and p62 after USA300 infection were examined by Western blotting and immunohistochemical staining. Bacterial burden analysis, hematoxylin-eosin staining, and Kaplan-Meier analysis were performed to evaluate the effect of autophagy on MRSA-induced sepsis. IFN-γ and IL-17 were analyzed by ELISA, and CD4⁺ T cell differentiation was assessed by flow cytometry. Our results showed that LC3-II/I and Beclin-1 were increased, while p62 was decreased after infection. Survival rates were decreased in the LC3B^-/- and Beclin-1^+/- groups, accompanied by worsened organ injuries and increased IFN-γ and IL-17 levels, whereas rapamycin alleviated organ damage, decreased IFN-γ and IL-17 levels, and improved the survival rate. However, there was no significant difference in bacterial burden. Flow cytometric analysis showed that rapamycin treatment decreased the frequencies of Th1 and Th17 cells, whereas these cells were upregulated in the LC3B^-/- and Beclin-1^+/- groups. Therefore, autophagy plays a protective role in MRSA-induced sepsis, which may be partly associated with the alleviation of organ injuries via the downregulation of Th1 and Th17 responses. These results provide a nonantibiotic treatment strategy for sepsis.

Interleukin-17A Triggers the Release of Platelet-Derived Factors Driving Vascular Endothelial Cells toward a Pro-Angiogenic State

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.

Interleukin-17 induces hypertension but does not impair cerebrovascular function in pregnant rats

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.

Interleukin-17A promotes the differentiation of bone marrow mesenchymal stem cells into neuronal cells

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.

IL-17 Induced Stromal Cell-Derived Factor-1 and Profibrotic Factor in Keloid-Derived Skin Fibroblasts via the STAT3 Pathway

The pathogenesis of keloids has not been elucidated, and the disease is thought to be caused by abnormal secretion of proinflammatory mediators and irregular responses to other inflammatory signals mediated by keloid fibroblasts (KFs). In this study, we investigated whether a local increase in interleukin IL-17 in keloid tissues stimulates the production of stromal cell–derived factor-1 (SDF-1) in KFs causing further recruitment of IL-17-producing T helper 17 (Th17) cells, which subsequently creates a positive feedback loop. Histological assessment was performed and the change in the expression of IL-17, IL-1β, IL-6, and TNF-α which of fibrosis and inflammation associated markers was examined. In addition, fibroblasts were treated with IL-17 in the presence or absence of STAT3 inhibitor STA-21; SDF-1 levels and fibrosis genes were measured. Our results showed that fibrotic reaction and expression of proinflammatory cytokines including IL-17 were most prominent in the growing margin (perilesional area) of keloid tissue and Th17 cells significantly infiltrated the perilesional area. In addition, IL-17 upregulated the expression of SDF-1, collagen, and α-SMA in KFs. Finally, STA-21 decreased SDF-1α expression and the expression of fibrosis genes in KFs even after IL-17 stimulation. Our study demonstrated that a local increase in IL-17 in keloid tissues stimulates the production of SDF-1 in KFs causing further recruitment of IL-17-producing T helper 17 (Th17) cells, which subsequently creates a positive feedback loop. These findings suggest that STAT3 inhibition can be used to treat keloid scars by reversing the vicious cycle between Th17 cells and KFs.

IL-17A and TNF Modulate Normal Human Spinal Entheseal Bone and Soft Tissue Mesenchymal Stem Cell Osteogenesis, Adipogenesis, and Stromal Function

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.

The SGLT2 inhibitor Empagliflozin attenuates interleukin-17A-induced human aortic smooth muscle cell proliferation and migration by targeting TRAF3IP2/ROS/NLRP3/Caspase-1-dependent IL-1β and IL-18 secretion

Chronic inflammation and persistent oxidative stress contribute to the development and progression of vascular proliferative diseases. We hypothesized that the proinflammatory cytokine interleukin (IL)-17A induces oxidative stress and amplifies inflammatory signaling in human aortic smooth muscle cells (SMC) via TRAF3IP2-mediated NLRP3/caspase-1-dependent mitogenic and migratory proinflammatory cytokines IL-1β and IL-18. Further, we hypothesized that these maladaptive changes are prevented by empagliflozin (EMPA), an SGLT2 (Sodium/Glucose Cotransporter 2) inhibitor. Supporting our hypotheses, exposure of cultured SMC to IL-17A promoted proliferation and migration via TRAF3IP2, TRAF3IP2-dependent superoxide and hydrogen peroxide production, NLRP3 expression, caspase-1 activation, and IL-1β and IL-18 secretion. Furthermore, NLRP3 knockdown, caspase-1 inhibition, and pretreatment with IL-1β and IL-18 neutralizing antibodies and IL-18BP, each attenuated IL-17A-induced SMC migration and proliferation. Importantly, SMC express SGLT2, and pre-treatment with EMPA attenuated IL-17A/TRAF3IP2-dependent oxidative stress, NLRP3 expression, caspase-1 activation, IL-1β and IL-18 secretion, and SMC proliferation and migration. Importantly, silencing SGLT2 attenuated EMPA-mediated inhibition of IL-17A-induced cytokine secretion and SMC proliferation and migration. EMPA exerted these beneficial antioxidant, anti-inflammatory, anti-mitogenic and anti-migratory effects under normal glucose conditions and without inducing cell death. These results suggest the therapeutic potential of EMPA in vascular proliferative diseases.

[IL-17A activates mouse lung fibroblasts through promoting chemokine CXCL12 secretion]

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.

IL-23 modulates histamine-evoked itch and responses of pruriceptors in mice

Accumulating evidence has highlighted the essential roles of cytokines in itch processing. Although IL-23 and Th17 cytokines are elevated in inflammatory skin disorders, their role in itch is unknown. Here, we investigated the role of IL-23 and IL-17A in itch response using an in vitro calcium imaging of mouse dorsal root ganglion (DRG) neurons and an in vivo behaviour test. Calcium imaging studies revealed that a few DRG neurons (~5%) responded to either IL-23 or IL-17A. Pretreatment cells with IL-23 significantly reduced calcium responses to histamine and capsaicin but not chloroquine. Behaviour experiments showed neither IL-23 nor IL-17A evoked scratching. IL-23 significantly decreased histamine-evoked scratching without affecting chloroquine-evoked scratching. There was no difference in scratching between IL-17A- and vehicle-treated groups. These results indicate that IL-23 might play a role in regulating histaminergic itch via modulation of TRPV1 activity.

Ikaros antagonizes DNA binding by STAT5 in pre-B cells

The IKZF1 gene, which encodes the Ikaros transcription factor, is frequently deleted or mutated in patients with B-cell precursor acute lymphoblastic leukemias that express oncogenes, like BCR-ABL, which activate the JAK-STAT5 pathway. Ikaros functionally antagonizes the transcriptional programs downstream of IL-7/STAT5 during B cell development, as well as STAT5 activity in leukemic cells. However, the mechanisms by which Ikaros interferes with STAT5 function is unknown. We studied the genomic distribution of Ikaros and STAT5 on chromatin in a murine pre-B cell line, and found that both proteins colocalize on >60% of STAT5 target regions. Strikingly, Ikaros activity leads to widespread loss of STAT5 binding at most of its genomic targets within two hours of Ikaros induction, suggesting a direct mechanism. Ikaros did not alter the level of total or phosphorylated STAT5 proteins, nor did it associate with STAT5. Using sequences from the Cish, Socs2 and Bcl6 genes that Ikaros and STAT5 target, we show that both proteins bind overlapping sequences at GGAA motifs. Our results demonstrate that Ikaros antagonizes STAT5 DNA binding, in part by competing for common target sequences. Our study has implications for understanding the functions of Ikaros and STAT5 in B cell development and transformation.

Interleukin-17A up-regulates thymic stromal lymphopoietin production by nasal fibroblasts from patients with allergic rhinitis

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.

Soluble CD14 Induces Pro-inflammatory Cytokines in Rheumatoid Arthritis Fibroblast-Like Synovial Cells via Toll-Like Receptor 4

Objectives: Synovial fluids of rheumatoid arthritis (RA) patients commonly contain high concentrations of soluble CD14 (sCD14). To investigate its potential role in RA pathogenesis, we tested whether sCD14 binding transmits a signal to fibroblast-like synoviocytes from RA patients (RA-FLS). Methods: The induction of pro-inflammatory cytokines, chemokines, and mediators by sCD14 stimulation of RA-FLS was quantified by real-time PCR and ELISA. Cell proliferation was assessed by the BrdU assay. LPS-RS, a Toll-like receptor 4 (TLR-4) antagonist, was used to block TLR-4 signaling. Results: Soluble CD14 induced the expression of IL-6 mRNA and secretion of the protein. The expression of other pro-inflammatory cytokines and mediators, such as TNF-α, IL-8, intercellular adhesion molecule-1 (ICAM-1), MMP-3, and RANK ligand (RANKL), was also induced by sCD14. In addition, sCD14 stimulation promoted RA-FLS proliferation. LPS-RS abolished IL-6, IL-8, and ICAM-1 mRNA induction by sCD14 in RA-FLS. On the other hand, TNF-α and IL-17A increased TLR-4 expression by RA-FLS and amplified their sCD14-induced IL-6 expression. Conclusions: Soluble CD14 transmits inflammatory signals to RA-FLS via TLR-4. The effects of sCD14 may be augmented in inflammatory milieu. Our results suggest that sCD14 is involved in the pathogenesis of RA and may be a novel therapeutic target.

Control of neutrophil influx during peritonitis by transcriptional cross-regulation of chemokine CXCL1 by IL-17 and IFN-γ

Neutrophil infiltration is a hallmark of peritoneal inflammation, but mechanisms regulating neutrophil recruitment in patients with peritoneal dialysis (PD)-related peritonitis are not fully defined. We examined 104 samples of PD effluent collected during acute peritonitis for correspondence between a broad range of soluble parameters and neutrophil counts. We observed an association between peritoneal IL-17 and neutrophil levels. This relationship was evident in effluent samples with low but not high IFN-γ levels, suggesting a differential effect of IFN-γ concentration on neutrophil infiltration. Surprisingly, there was no association of neutrophil numbers with the level of CXCL1, a key IL-17-induced neutrophil chemoattractant. We investigated therefore the production of CXCL1 by human peritoneal mesothelial cells (HPMCs) under in vitro conditions mimicking clinical peritonitis. Stimulation of HPMCs with IL-17 increased CXCL1 production through induction of transcription factor SP1 and activation of the SP1-binding region of the CXCL1 promoter. These effects were amplified by TNFα. In contrast, IFN-γ dose-dependently suppressed IL-17-induced SP1 activation and CXCL1 production through a transcriptional mechanism involving STAT1. The SP1-mediated induction of CXCL1 was also observed in HPMCs exposed to PD effluent collected during peritonitis and containing IL-17 and TNFα, but not IFN-γ. Supplementation of the effluent with IFN-γ led to a dose-dependent activation of STAT1 and a resultant inhibition of SP1-induced CXCL1 expression. Transmesothelial migration of neutrophils in vitro increased upon stimulation of HPMCs with IL-17 and was reduced by IFN-γ. In addition, HPMCs were capable of binding CXCL1 at their apical cell surface. These observations indicate that changes in relative peritoneal concentrations of IL-17 and IFN-γ can differently engage SP1-STAT1, impacting on mesothelial cell transcription of CXCL1, whose release and binding to HPMC surface may determine optimal neutrophil recruitment and retention during peritonitis. © 2020 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Interleukin-22 orchestrates a pathological endoplasmic reticulum stress response transcriptional programme in colonic epithelial cells

OBJECTIVE

The functional role of interleukin-22 (IL22) in chronic inflammation is controversial, and mechanistic insights into how it regulates target tissue are lacking. In this study, we evaluated the functional role of IL22 in chronic colitis and probed mechanisms of IL22-mediated regulation of colonic epithelial cells.

DESIGN

To investigate the functional role of IL22 in chronic colitis and how it regulates colonic epithelial cells, we employed a three-dimentional mini-gut epithelial organoid system, in vivo disease models and transcriptomic datasets in human IBD.

RESULTS

As well as inducing transcriptional modules implicated in antimicrobial responses, IL22 also coordinated an endoplasmic reticulum (ER) stress response transcriptional programme in colonic epithelial cells. In the colon of patients with active colonic Crohn's disease (CD), there was enrichment of IL22-responsive transcriptional modules and ER stress response modules. Strikingly, in an IL22-dependent model of chronic colitis, targeting IL22 alleviated colonic epithelial ER stress and attenuated colitis. Pharmacological modulation of the ER stress response similarly impacted the severity of colitis. In patients with colonic CD, antibody blockade of IL12p40, which simultaneously blocks IL12 and IL23, the key upstream regulator of IL22 production, alleviated the colonic epithelial ER stress response.

CONCLUSIONS

Our data challenge perceptions of IL22 as a predominantly beneficial cytokine in IBD and provide novel insights into the molecular mechanisms of IL22-mediated pathogenicity in chronic colitis. Targeting IL22-regulated pathways and alleviating colonic epithelial ER stress may represent promising therapeutic strategies in patients with colitis.

TRIAL REGISTRATION NUMBER

NCT02749630.

Bidirectional Cross-Talk between Biliary Epithelium and Th17 Cells Promotes Local Th17 Expansion and Bile Duct Proliferation in Biliary Liver Diseases

There is no effective treatment for autoimmune biliary diseases. Therefore, understanding their immunopathology is crucial. The biliary epithelial cells (BEC), expressing TLR-4, are constantly exposed to gut microbes and bacterial wall LPS, and in settings of inflammation, the immune infiltrate is dense within the peribiliary region of human liver. By dual immunohistochemistry, we affirm human intrahepatic T cell infiltrate includes CCR6+CD4+ and AhR+CD4+ T cells with potential for plasticity to Th17 phenotype. Mechanistically, we demonstrate that Th1 and Th17 inflammatory cytokines and LPS enhance human primary BEC release of the CCR6 ligand CCL20 and BEC secretion of Th17-polarizing cytokines IL-6 and IL-1β. Cell culture assays with human BEC secretome showed that secretome polarizes CD4 T cells toward a Th17 phenotype and supports the survival of Th17 cells. BEC secretome did not promote Th1 cell generation. Additionally, we give evidence for a mutually beneficial feedback of the type 17 cell infiltrate on BEC, showing that treatment with type 17 cytokines increases BEC proliferation, as monitored by Ki67 and activation of JAK2-STAT3 signaling. This study identifies human BEC as active players in determining the nature of the intrahepatic immune microenvironment. In settings of inflammation and/or infection, biliary epithelium establishes a prominent peribiliary type 17 infiltrate via recruitment and retention and enhances polarization of intrahepatic CD4 cells toward Th17 cells via type 17 cytokines, and, reciprocally, Th17 cells promote BEC proliferation for biliary regeneration. Altogether, we provide new insight into cross-talk between Th17 lymphocytes and human primary biliary epithelium in biliary regenerative pathologies.

Antagonistic Effects of IL-4 on IL-17A-Mediated Enhancement of Epidermal Tight Junction Function

Atopic dermatitis (AD) is the most common chronic and relapsing inflammatory skin disease. AD is typically characterized by skewed T helper (Th) 2 inflammation, yet other inflammatory profiles (Th1, Th17, Th22) have been observed in human patients. How cytokines from these different Th subsets impact barrier function in this disease is not well understood. As such, we investigated the impact of the canonical Th17 cytokine, IL-17A, on barrier function and protein composition in primary human keratinocytes and human skin explants. These studies demonstrated that IL-17A enhanced tight junction formation and function in both systems, with a dependence on STAT3 signaling. Importantly, the Th2 cytokine, IL-4 inhibited the barrier-enhancing effect of IL-17A treatment. These observations propose that IL-17A helps to restore skin barrier function, but this action is antagonized by Th2 cytokines. This suggests that restoration of IL-17/IL-4 ratio in the skin of AD patients may improve barrier function and in so doing improve disease severity.

LL-37 alone and in combination with IL17A enhances proinflammatory cytokine expression in parallel with hyaluronan metabolism in human synovial sarcoma cell line SW982-A step toward understanding the development of inflammatory arthritis

LL-37 is the only human cathelicidin-family host defense peptide and has been reported to interact with invading pathogens causing inflammation at various body sites. Recent studies showed high levels of LL-37 in the synovial-lining membrane of patients with rheumatoid arthritis, a common type of inflammatory arthritis. The present study aims to investigate the role of LL-37 on mechanisms associated with pathogenesis of inflammatory arthritis. The effects of LL-37 on the expression of proinflammatory cytokines, hyaluronan (HA) metabolism-related genes, cell death-related pathways, and cell invasion were investigated in SW982, a human synovial sarcoma cell line. Time-course measurements of proinflammatory cytokines and mediators showed that LL-37 significantly induced IL6 and IL17A mRNA levels at early time points (3–6 hr). HA-metabolism-related genes (i.e., HA synthase 2 (HAS2), HAS3, hyaluronidase 1 (HYAL1), HYAL2, and CD44) were co-expressed in parallel. In combination, LL-37 and IL17A significantly enhanced PTGS2, TNF, and HAS3 gene expression concomitantly with the elevation of their respective products, PGE2, TNF, and HA. Cell invasion rates and FN1 gene expression were also significantly enhanced. However, LL-37 alone or combined with IL17A did not affect cell mortality or cell cycle. Treatment of SW982 cells with both LL-37 and IL17A significantly enhanced IKK and p65 phosphorylation. These findings suggest that the chronic production of a high level of LL-37 may synchronize with its downstream proinflammatory cytokines, especially IL17A, contributing to the co-operative enhancement of pathogenesis mechanisms of inflammatory arthritis, such as high production of proinflammatory cytokines and mediators together with the activation of HA-metabolism-associated genes and cell invasion.

[IL-17 regulates the expression of RANKL and OPG in human periodontal ligament fibroblasts by activating p38MAPK signaling pathway]

Objective To illuminate whether IL-17 regulates receptor activator of NF-κB ligand (RANKL) and osteoprotegerin (OPG) expression in human periodontal ligament fibroblasts (HPDLFs) via p38MAPK signaling pathway. Methods HPDLFs were incubated in the presence of 20 ng/mL IL-17 for 0, 20, 40, 60 and 80 minutes. HPDLFs were divided randomly into 6 groups: control group, dimethyl sulfoxide (DMSO) group, p38MAPK pathway inhibitor SB203580 group, IL-17 group, IL-17 combined with DMSO group and IL-17 combined with SB203580 group. SB203580 (10 μmol/L) and IL-17 (20 ng/mL) were added to the corresponding groups. Real-time quantitative PCR was used to detect the expression of RANKL and OPG mRNAs in HPDLFs. The levels of phospho-p38MAPK (p-p38MAPK) and RANKL protein were measured using Western blot analysis. The protein level of OPG was detected by ELISA. Results After IL-17 stimulation, the expression level of p-p38MAPK protein gradually increased starting from 0 minute and reached its highest level at 60 minutes. It started to decline at 80 minutes. Stimulation with IL-17 could increase the mRNA and protein expression level of RANKL but decrease the mRNA and protein expression level of OPG. Nevertheless, unlike the IL-17 group, IL-17 combined with inhibitor SB203580 decreased the expression of RANKL mRNA and protein and increased OPG mRNA. Conclusion IL-17 can enhance the expression of RANKL in human periodontal fibroblasts and inhibit the expression of OPG mRNA through the p38MAPK signal transduction pathways.