A Truncated IL-17RC Peptide Ameliorates Synovitis and Bone Destruction of Arthritic Mice

Mitochondrial-Targeted Ratiometric Near-Infrared Fluorescence Probe for Monitoring Nitric Oxide in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a destructive autoimmune disease, where nitric oxide (NO) is closely implicated in the inflammatory processes of RA. Therefore, direct visualization of NO is essential to assess the pathological changes in RA. Herein, a mitochondrial-targeted near-infrared ratiometric fluorescent probe (NFL-NH2), based on the intramolecular charge transfer effect, was synthesized and applied to monitor the changes of NO content in early RA. Specially, probe NFL-NH2 showed a 44-fold fluorescent intensity ratio (I705/I780) response toward NO with a detection limit of 0.536 nM, enabling qualitative and quantitative analysis of NO. Additionally, NFL-NH2 can accurately target mitochondria and sensitively detect exogenous and endogenous NO in RAW 264.7 cells. Notably, in vivo RA monitoring assays demonstrated that NFL-NH2 can rapidly detect NO levels associated with the inflammatory damage degree in RA mice models by ratiometric fluorescence imaging. These results validate that NFL-NH2 holds significant potential for diagnosing NO-mediated RA diseases.

Biomass-related PM2.5 induced inflammatory microenvironment via IL-17F/IL-17RC axis

Biomass exposure is a significant environmental risk factor for COPD, but the underlying mechanisms have not yet been fully elucidated. Inflammatory microenvironment has been shown to drive the development of many chronic diseases. Pollution exposure can cause increased levels of inflammatory factors in the lungs, leading to an inflammatory microenvironment which is prevalent in COPD. Our findings revealed that IL-17F was elevated in COPD, while exposure to biomass led to increased expression of IL-17F in both alveolar epithelial and macrophage cells in mice. Blocking IL-17F could alleviate the lung inflammation induced by seven days of biomass exposure in mice. We employed a transwell co-culture system to simulate the microenvironment and investigate the interactions between MLE-12 and MH-S cells. We demonstrated that anti-IL-17F antibody attenuated the inflammatory responses induced by BRPM2.5 in MLE-12 and MH-S co-cultured with BRPM2.5-MLE-12, which reduced inflammatory changes in microenvironment. We found that IL-17RC, an important receptor for IL-17F, played a key role in the interactions. Knockout of IL-17RC in MH-S resulted in inhibited IL-17F signaling and attenuated inflammatory response after MH-S co-culture with BRPM2.5-MLE-12. Our investigation suggests that BRPM2.5 induces lung epithelial-macrophage interactions via IL-17F/IL-17RC axis regulating the inflammatory response. These results may provide a novel strategy for effective prevention and treatment of biomass-related COPD.

Interleukin-17 receptor C is essential for the pro-inflammatory pathogenicity of granulocyte-macrophage-colony-stimulating factor-producing T helper cells in experimental autoimmune uveitis

Autoimmune uveitis is an inflammatory disorder of the eye triggered by the responses of autoreactive T cells to ocular autoantigens. This study aims to understand the role of granulocyte-macrophage-colony-stimulating factor (GM-CSF)-producing T helper (ThGM) cells in the pathophysiology of mouse experimental autoimmune uveitis (EAU). We established an EAU model by immunizing mice with interphotoreceptor retinoid-binding protein (IRBP) 651-670. Splenic or eye-infiltrating ThGM cells were analyzed and enriched by flow cytometry according to the levels of an array of surface markers, transcription factors, and cytokines. Lentiviral transduction was conducted to silence or overexpress the target gene in differentiated ThGM cells. The adoptive transfer was applied to determine the pathogenicity of ThGM cells in vivo. We found that ThGM cells were present in the spleen and the eye after EAU induction. Both splenic and eye-infiltrating ThGM cells were phenotypically CD4⁺CCR7^-CXCR3^-CCR6^-CCR10^hi. Eye-infiltrating ThGM cells up-regulated interleukin-1β (IL-1β), interleukin-6 (IL-6), and IL-17 receptor C (IL-17RC) relative to splenic ThGM cells. IL-17RC overexpression enabled interleukin-17A (IL-17A)-induced up-regulation of IL-1β and IL-6 production in ThGM cells. Adoptive transfer of IL-17RC overexpressing ThGM cells exacerbated EAU severity, as evidenced by a higher histology score as well as increased pro-inflammatory cytokines and inflammatory cells in the eye. However, IL-17RC-silenced ThGM cells did not impact EAU. Therefore, for the first time, this study unveils the essential pro-inflammatory role of IL-17RC-expressing ThGM cells in EAU pathophysiology. We discovered a novel mechanism underlying the pathophysiology of autoimmune uveitis.

Recent Advances in Nanomaterials for Asthma Treatment

Asthma is a chronic airway inflammatory disease with complex mechanisms, and these patients often encounter difficulties in their treatment course due to the heterogeneity of the disease. Currently, clinical treatments for asthma are mainly based on glucocorticoid-based combination drug therapy; however, glucocorticoid resistance and multiple side effects, as well as the occurrence of poor drug delivery, require the development of more promising treatments. Nanotechnology is an emerging technology that has been extensively researched in the medical field. Several studies have shown that drug delivery systems could significantly improve the targeting, reduce toxicity and improve the bioavailability of drugs. The use of multiple nanoparticle delivery strategies could improve the therapeutic efficacy of drugs compared to traditional delivery methods. Herein, the authors presented the mechanisms of asthma development and current therapeutic methods. Furthermore, the design and synthesis of different types of nanomaterials and micromaterials for asthma therapy are reviewed, including polymetric nanomaterials, solid lipid nanomaterials, cell membranes-based nanomaterials, and metal nanomaterials. Finally, the challenges and future perspectives of these nanomaterials are discussed to provide guidance for further research directions and hopefully promote the clinical application of nanotherapeutics in asthma treatment.

A Review of Non-Invasive Drug Delivery through Respiratory Routes

With rapid and non-invasive characteristics, the respiratory route of administration has drawn significant attention compared with the limitations of conventional routes. Respiratory delivery can bypass the physiological barrier to achieve local and systemic disease treatment. A scientometric analysis and review were used to analyze how respiratory delivery can contribute to local and systemic therapy. The literature data obtained from the Web of Science Core Collection database showed an increasing worldwide tendency toward respiratory delivery from 1998 to 2020. Keywords analysis suggested that nasal and pulmonary drug delivery are the leading research topics in respiratory delivery. Based on the results of scientometric analysis, the research hotspots mainly included therapy for central nervous systems (CNS) disorders (Parkinson's disease, Alzheimer's disease, depression, glioblastoma, and epilepsy), tracheal and bronchial or lung diseases (chronic obstructive pulmonary disease, asthma, acute lung injury or respiratory distress syndrome, lung cancer, and idiopathic pulmonary fibrosis), and systemic diseases (diabetes and COVID-19). The study of advanced preparations contained nano drug delivery systems of the respiratory route, drug delivery barriers investigation (blood-brain barrier, BBB), and chitosan-based biomaterials for respiratory delivery. These results provided researchers with future research directions related to respiratory delivery.

Identification of two interleukin 17 receptor C (IL-17RC) genes and their binding activities to three IL-17A/F ligands in the Japanese medaka, Oryzias latipes

In mammals, interleukin (IL)-17 receptor C (IL-17RC) and IL-17RA mediate IL-17A and IL-17F signaling to produce mucin, antimicrobial peptides, and maintain healthy intestinal flora. However, IL-17RC signaling in fish remains unclear. In this study, three il17rc transcripts (il17rca1, il17rca2, and il17rcb) from the Japanese medaka (Oryzias latipes) were cloned; il17rca1 and il17rca2 mRNAs were alternatively spliced from il17rca pre-mRNA as transcript variants. The il17rca and il17rcb genes were located on chromosomes 7 and 5, respectively. Teleost clades containing medaka il17rca and il17rcb clustered separately from the tetrapod clade. In adult tissues, il17rca1 expression was significantly higher than il17rca2 and il17rcb. Conversely, il17rcb expression was significantly higher in embryos and larvae. These expression patterns changed following infection with Edwardsiella piscicida and Aeromonas hydrophila. Furthermore, an immunoprecipitation assay using recombinant IL-17RCs and rIL-17A/Fs suggested that, in teleosts, three ligands could function in signaling through two IL-17RCs.

Self-assembled chitosan nanoparticles for intranasal delivery of recombinant protein interleukin-17 receptor C (IL-17RC): preparation and evaluation in asthma mice

Asthma is mentioned as a chronic airway inflammatory disease, whose pathogenesis is complicated. The promotion of inflammation in asthma by IL-17A and IL-17F has been confirmed. In addition to covalent homodimers, both cytokines are also able to form heterodimers, further inducing downstream pathways via binding to the IL-17RA and IL-17RC receptor complex. In recent years, IL-17RA and its signal transduction pathway have been extensively researched. IL-17RC, however, remains relatively unexplored. In the present study, we self-assembled chitosan (CS) nanoparticles for intranasal delivery of recombinant protein IL-17RC (rIL-17RC) and preliminarily investigated its effect on a murine model of allergic asthma induced by ovalbumin (OVA). rIL-17RC was produced by the prokaryotic expression system and encapsulated into the CS nanoparticles via ionic cross-linking technique. The results showed that CS-RC nanoparticles via intranasal intervention significantly caused inhibition of mucus secretion and airway inflammatory cell infiltration, and reduced IL-4, IL-17, IL-17F levels in BALF. Hence, delivering receptor proteins such as IL-17RC, through CS nanoparticles as a carrier, could be an attractive therapeutic intervention for asthma.

HIF1α inhibition facilitates Leflunomide-AHR-CRP signaling to attenuate bone erosion in CRP-aberrant rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory disorder characterized by progressive bone erosion. Leflunomide is originally developed to suppress inflammation via its metabolite A77 1726 to attenuate bone erosion. However, distinctive responsiveness to Leflunomide is observed among RA individuals. Here we show that Leflunomide exerts immunosuppression but limited efficacy in RA individuals distinguished by higher serum C-reactive protein (CRP^Higher, CRP^H), whereas the others with satisfactory responsiveness to Leflunomide show lower CRP (CRP^Lower, CRP^L). CRP inhibition decreases bone erosion in arthritic rats. Besides the immunomodulation via A77 1726, Leflunomide itself induces AHR-ARNT interaction to inhibit hepatic CRP production and attenuate bone erosion in CRP^L arthritic rats. Nevertheless, high CRP in CRP^H rats upregulates HIF1α, which competes with AHR for ARNT association and interferes Leflunomide-AHR-CRP signaling. Hepatocyte-specific HIF1α deletion or a HIF1α inhibitor Acriflavine re-activates Leflunomide-AHR-CRP signaling to inhibit bone erosion. This study presents a precision medicine-based therapeutic strategy for RA.

Leflunomide is used for the treatment of rheumatoid arthritis. Here, the authors show that effectiveness is limited in patients with higher levels of serum c-reactive protein (CRP). Using animal models, they show that higher CRP induces HIF1a expression, which in turn interferes with Leflunomide signalling, and that effectiveness of the drug is restored when HIF1a is pharmacologically inhibited.

IL17RC affects the predisposition to thoracic ossification of the posterior longitudinal ligament

Background

Thoracic ossification of the posterior longitudinal ligament (T-OPLL) can cause thoracic spinal stenosis, which results in intractable myelopathy and radiculopathy. The etiology of T-OPLL is unknown and the condition is difficult to treat surgically. Whole-genome sequencing identified a genetic variant at rs199772854 of the interleukin 17 receptor C (IL17RC) gene as a potentially pathogenic locus associated with T-OPLL. We aimed to determine whether the rs199772854A site mutation causes abnormal expression of the IL17RC in Han Chinese patients with T-OPLL and predict the possible pathogenic mechanisms of T-OPLL. Analyses were performed to determine whether IL17RC is involved in the pathogenicity of T-OPLL.

Methods

Peripheral blood and OPLL tissue were collected from a total of 72 patients with T-OPLL disease (36 patients carrying the rs199772854A site mutation in IL17RC and 36 wild-type patients). The expression of IL17RC was analyzed by enzyme-linked immunosorbent assay, reverse transcription-quantitative polymerase chain reaction, immunohistochemistry, and Western blotting.

Results

rs199772854A mutation resulted in markedly increased IL17RC gene expression levels in peripheral blood samples and the OPLL tissue obtained following clinical surgery (P < 0.05).

Conclusions

The results suggest that the rs199772854A site mutation of IL17RC can significantly increase the expression of IL17RC. The IL17RC gene rs199772854A site polymorphism is a potential pathogenic mutation in T-OPLL disease, which may be associated with the occurrence of T-OPLL.

Depleting the carboxy-terminus of human Wnt5a attenuates collagen-induced arthritis in DBA/1 mice

Wnt5a signalling plays pathological roles in synovial inflammation and bone destruction. In the present study, we designed four human Wnt5a-based DNA recombinants and detected their effects on immunogenicity and anti-rheumatism in a collagen-induced arthritis (CIA) model. Histomorphometry and micro-CT scanning showed that the phWnt5a-NL was superior to other recombinants because it resulted in decreased severity of arthritis, histopathological scores of synovial inflammation and bone erosion in CIA mice. In addition, ELISA and TRAP staining showed that the phWnt5a-NL-immunized CIA mice had reductions in the serum concentrations of the rheumatoid-associated cytokines IL-1β and RANKL and in osteoclastogenesis. Furthermore, flow cytometry showed that the phWnt5a-NL treatment increased the percentage of Treg cells. Finally, western blotting analysis showed that the phWnt5a-NL-immunization interrupted β-catenin and JNK expression in osteoclast precursors derived from the CIA mice. The results suggest that depleting the carboxy-terminus in hWnt5a-based DNA recombinants may be beneficial for the treatment of chronic inflammatory disorders involving bone resorption.