Nav1.7 as a chondrocyte regulator and therapeutic target for osteoarthritis.

Osteoarthritis (OA) is the most common joint disease. Currently there are no effective methods that simultaneously prevent joint degeneration and reduce pain1. Although limited evidence suggests the existence of voltage-gated sodium channels (VGSCs) in chondrocytes2, their expression and function in chondrocytes and in OA remain essentially unknown. Here we identify Nav1.7 as an OA-associated VGSC and demonstrate that human OA chondrocytes express functional Nav1.7 channels, with a density of 0.1 to 0.15 channels per µm2 and 350 to 525 channels per cell. Serial genetic ablation of Nav1.7 in multiple mouse models demonstrates that Nav1.7 expressed in dorsal root ganglia neurons is involved in pain, whereas Nav1.7 in chondrocytes regulates OA progression. Pharmacological blockade of Nav1.7 with selective or clinically used pan-Nav channel blockers significantly ameliorates the progression of structural joint damage, and reduces OA pain behaviour. Mechanistically, Nav1.7 blockers regulate intracellular Ca2+ signalling and the chondrocyte secretome, which in turn affects chondrocyte biology and OA progression. Identification of Nav1.7 as a novel chondrocyte-expressed, OA-associated channel uncovers a dual target for the development of disease-modifying and non-opioid pain relief treatment for OA.

Weighted gene co-expression network analysis and machine learning identified the lipid metabolism-related gene LGMN as a novel biomarker for keloid.

The aetiology of keloid formation remains unclear, and existing treatment modalities have not definitively established a successful approach. Therefore, it is necessary to identify reliable and novel keloid biomarkers as potential targets for therapeutic interventions. In this study, we performed differential expression analysis and functional enrichment analysis on the keloid related datasets, and found that multiple metabolism-related pathways were associated with keloid formation. Subsequently, the differentially expressed genes (DEGs) were intersected with the results of weighted gene co-expression network analysis (WGCNA) and the lipid metabolism-related genes (LMGs). Then, three learning machine algorithms (SVM-RFE, LASSO and Random Forest) together identified legumain (LGMN) as the most critical LMGs. LGMN was overexpressed in keloid and had a high diagnostic performance. The protein-protein interaction (PPI) network related to LGMN was constructed by GeneMANIA database. Functional analysis of indicated PPI network was involved in multiple immune response-related biological processes. Furthermore, immune infiltration analysis was conducted using the CIBERSORT method. M2-type macrophages were highly infiltrated in keloid tissues and were found to be significantly and positively correlated with LGMN expression. Gene set variation analysis (GSVA) indicated that LGMN may be related to promoting fibroblast proliferation and inhibiting their apoptosis. Moreover, eight potential drug candidates for keloid treatment were predicted by the DSigDB database. Western blot, qRT-PCR and immunohistochemistry staining results confirmed that LGMN was highly expressed in keloid. Collectively, our findings may identify a new biomarker and therapeutic target for keloid and contribute to the understanding of the potential pathogenesis of keloid.

IUPHAR ECR review: The cGAS-STING pathway: Novel functions beyond innate immune and emerging therapeutic opportunities.

Stimulator of interferon genes (STING) is a crucial innate immune sensor responsible for distinguishing pathogens and cytosolic DNA, mediating innate immune signaling pathways to defend the host. Recent studies have revealed additional regulatory functions of STING beyond its innate immune-related activities, including the regulation of cellular metabolism, DNA repair, cellular senescence, autophagy and various cell deaths. These findings highlight the broader implications of STING in cellular physiology beyond its role in innate immunity. Currently, approximately 10 STING agonists have entered the clinical stage. Unlike inhibitors, which have a maximum inhibition limit, agonists have the potential for infinite amplification. STING signaling is a complex process that requires precise regulation of STING to ensure balanced immune responses and prevent detrimental autoinflammation. Recent research on the structural mechanism of STING autoinhibition and its negative regulation by adaptor protein complex 1 (AP-1) provides valuable insights into its different effects under physiological and pathological conditions, offering a new perspective for developing immune regulatory drugs. Herein, we present a comprehensive overview of the regulatory functions and molecular mechanisms of STING beyond innate immune regulation, along with updated details of its structural mechanisms. We discuss the implications of these complex regulations in various diseases, emphasizing the importance and feasibility of targeting the immunity-dependent or immunity-independent functions of STING. Moreover, we highlight the current trend in drug development and key points for clinical research, basic research, and translational research related to STING.

Safety, pharmacokinetics and pharmacodynamics of HRS-7535, a novel oral small molecule glucagon-like peptide-1 receptor agonist, in healthy participants: A phase 1, randomized, double-blind, placebo-controlled, single- and multiple-ascending dose, and food effect trial.

AIM: To assess the safety, tolerability, pharmacokinetics (PKs) and pharmacodynamics of HRS-7535, a novel glucagon-like peptide-1 receptor agonist (GLP-1RA), in healthy participants. MATERIALS AND METHODS: This phase 1 trial consisted of single-ascending dose (SAD), food effect (FE) and multiple-ascending dose (MAD) parts. In the SAD part, participants were randomized (6:2) to receive HRS-7535 (at doses of 15, 60 and 120 mg; administered orally once daily) or placebo. In the FE part, participants were randomized (8:2) to receive a single dose of 90-mg HRS-7535 or placebo, in both fed and fasted states. In the MAD part, participants were randomized (18:6) to receive daily HRS-7535 (120 mg [30/60/90/120-mg titration scheme]) or placebo for 28 days. The primary endpoints were safety and tolerability. RESULTS: Nausea and vomiting were the most frequently reported AEs across all three parts. In the SAD part, the median Tmax was 5.98-5.99 hours and the geometric mean t1/2 was 5.28-9.08 hours across the HRS-7535 dosing range. In the MAD part, the median Tmax was 5.98-10.98 hours and the geometric mean t1/2 was 6.48-8.42 hours on day 28 in participants on HRS-7535. PKs were approximately dose-proportional. On day 29 in the MAD part, the mean (percentage) reduction in body weight from baseline was 4.38 kg (6.63%) for participants who received HRS-7535, compared with 0.8 kg (1.18%) for those participants who received a placebo. CONCLUSIONS: HRS-7535 exhibited a safety and tolerability profile consistent with other GLP-1RAs and showed PKs suitable for once-daily dosing. These findings support further clinical development of HRS-7535 for type 2 diabetes.

Macrophage membrane-camouflaged biomimetic nanoparticles for rheumatoid arthritis treatment via modulating macrophage polarization.

Rheumatoid arthritis (RA) is a debilitating autoimmune disease characterized by chronic joint inflammation and cartilage damage. Current therapeutic strategies often result in side effects, necessitating the development of targeted and safer treatment options. This study introduces a novel nanotherapeutic system, 2-APB@DGP-MM, which utilizes macrophage membrane (MM)-encapsulated nanoparticles (NPs) for the targeted delivery of 2-Aminoethyl diphenylborinate (2-APB) to inflamed joints more effectively. The NPs are designed with a matrix metalloproteinase (MMP)-cleavable peptide, allowing for MMP-responsive drug release within RA microenvironment. Comprehensive in vitro and in vivo assays confirmed the successful synthesis and loading of 2-APB into the DSPE-GPLGVRGC-PEG (DGP) NPs, as well as their ability to repolarize macrophages from a pro-inflammatory M1 to an anti-inflammatory M2 phenotype. The NPs demonstrated high biocompatibility, low cytotoxicity, and enhanced cellular uptake. In a collagen-induced arthritis (CIA) mouse model, intra-articular injection of 2-APB@DGP-MM significantly reduced synovial inflammation and cartilage destruction. Histological analysis corroborated these findings, demonstrating marked improvements in joint structure and delayed disease progression. Above all, the 2-APB@DGP-MM nanotherapeutic system offers a promising and safe approach for RA treatment by modulating macrophage polarization and delivering effective agents to inflamed joints.

A suprapubic refractory skin ulcer following keloid radiotherapy: from hyper-proliferation to hypo-proliferation.

Radiation-induced skin ulcer following cancer and/or tumour is well-documented in the literature. However, radiation-induced skin ulcer following the excision of keloid is yet to be reported. Here, we report the case of a 33-year-old female patient with a suprapubic skin ulcer of five months' duration following keloid treatment with electron beam therapy at recommended dosage. Various examinations, including a skin biopsy, metagenomic sequencing, magnetic resonance imaging and immunochemistry, indicated that the skin ulcer was induced by radiotherapy. While postoperative radiotherapy has been recommended immediately following keloid excision to reduce the risk of recurrence, the present case highlights the risk of skin refractory ulcer following keloid radiotherapy.

A Three-Step Approach (MUC) for Umbilicoplasty: Creating a Deep Umbilical Depression in Lipoabdominoplasty.

BACKGROUND: Various methods of umbilicoplasty have been proposed to create an aesthetically pleasing umbilicus. However, following conventional lipoabdominoplasty, some patients, particularly those with a thin layer of abdominal fat, may exhibit a shallow navel. METHODS: A modified umbilicoplasty with a three-step approach was performed between Jan 2019 and Mar 2023. The three-step procedure included multiple plications, umbilical stalk fixation, umbilical insertion and central gathering (MUC). Patients were followed up for at least 6 months. Umbilical depth and complications were recorded. RESULTS: A total of 36 patients were performed with MUC umbilicoplasty, with a mean age of 36.1 years. Patients were satisfied with umbilical appearance. The average depth of the navel after MUC procedure was 1.8±0.3 cm. A patient developed a hypertrophic scar in the umbilicus, which was treated with an intralesional injection of triamcinolone acetonide. No other complications were observed. CONCLUSION: The MUC approach to umbilicoplasty provides a deep umbilical depression with minimal scars. This three-step procedure is particularly beneficial for patients with a thin layer of abdominal fat. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Shear Wave Elastography for Assessment of Changes in Abdominal Soft Tissues after Lipoabdominoplasty.

BACKGROUND: The changes in the elasticity of the abdominal skin, subcutaneous tissues and muscles after lipoabdominoplasty are still unknown. The aim of this study was to provide an objective assessment of tissue elasticity after lipoabdominoplasty using ultrasound elastography. METHODS: A total of 21 female patients (31-41 years old) who underwent lipoabdominoplasty from Oct 2019 to Mar 2022 were included in this retrospective study. The elastography values of the skin, subcutaneous tissues and abdominal muscles were obtained with the ultrasound shear wave elasticity imaging system pre-operation (Pre) and 6 months post-operation (Post) at four different points. RESULTS: Twenty-one female patients were included. The elasticity of the abdominal skin, subcutaneous tissues, rectus abdominis and external oblique abdominis significantly increased at 6 months post-operation. The improvements in abdominal soft tissue elasticity were not uniform across the examined points. CONCLUSIONS: Significant changes in the elasticity of the abdominal skin, subcutaneous tissues and muscles were observed after lipoabdominoplasty. Ultrasound elastographic assessment was objective and feasible for evaluating the effect of lipoabdominoplasty on abdominal soft tissue. LEVEL OF EVIDENCE III: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

LC-MS/MS determination of HY072808, a novel candidate for treating atopic dermatitis, and its active metabolite: Application to a first-in-human pharmacokinetic study.

HY072808 is a novel phosphodiesterase 4 inhibitor currently under clinical development to treat atopic dermatitis. The first step is to address the pharmacokinetics and safety after topical administration of HY072808 ointments in healthy humans. In this study, we developed a highly sensitive liquid chromatography-tandem mass spectrometry method to determine plasma HY072808 and its active metabolite, ZZ24, in tiny amounts. The plasma samples were prepared using a simple liquid-liquid extraction method. Liquid chromatographic separation was achieved by gradient elution. The MS/MS quantification was performed in positive ion mode via multiple reaction monitoring. The method showed satisfactory linearity from 10 to 4,000 pg/ml for HY072808 and ZZ24. There was no significant interference from blank plasma. The method was validated for accuracy and precision, matrix effect and extraction recovery, dilution integrity, injection carryover and stability according to the related guidelines of the regulatory authorities. The HY072808 and ZZ24 concentrations in human plasma from a clinical trial were determined using this method. In conclusion, the validated method was robust and could be utilized to support the clinical development of HY072808.

Hybrid Autologous Costal Cartilage Grafting for Augmentation Rhinoplasty in Asian Patients.

BACKGROUND: Autologous costal cartilage has been used for augmentation rhinoplasty in Asia for many years. This study aimed to assess the effectiveness and safety of hybrid grafting of costal cartilage for dorsal augmentation, septal reconstruction, and tip augmentation for Asian patients. METHODS: A surgical technique was introduced and patients having rhinoplasty using this technique from April 2020 to March 2021 were retrospectively studied. In this technique, costal cartilage was meticulously carved or diced and grafted in various ways mainly based on the anatomic characteristics of nasal skin and subcutaneous soft tissues as well as bone and cartilage framework. The surgical outcomes, patient satisfaction, and complications retrieved from the documented medical records were reviewed and analyzed. RESULTS: Twenty-five patients having rhinoplasty with the proposed technique were followed up from 6 months to 12 months. As for cosmetic outcomes, 21 patients were graded as good, 3 patients were graded as fair, and only 1 patient was graded as poor. Those patients who were not graded as good had over-rotated tips, insufficient dorsal augmentation, or asymmetry of nostrils and soft tissue contracture. The overall patient satisfaction was as high as 96.0%. Local infection occurred in 1 patient and hematoma was not observed. Warping and visibility of costal cartilage were not observed in any patients. Slight displacement of diced cartilages was found in 2 patients near the radix 1 week postoperatively. CONCLUSIONS: Hybrid autologous costal cartilage grafts can be used for both tip refinement and dorsal augmentation for East Asian patients and achieve an outcome of a natural-looking nose with minimal complications. LEVEL OF EVIDENCE: Level IV.

Cartilage-Related Collagens in Osteoarthritis and Rheumatoid Arthritis: From Pathogenesis to Therapeutics.

Collagens serve essential mechanical functions throughout the body, particularly in the connective tissues. In articular cartilage, collagens provide most of the biomechanical properties of the extracellular matrix essential for its function. Collagen plays a very important role in maintaining the mechanical properties of articular cartilage and the stability of the ECM. Noteworthily, many pathogenic factors in the course of osteoarthritis and rheumatoid arthritis, such as mechanical injury, inflammation, and senescence, are involved in the irreversible degradation of collagen, leading to the progressive destruction of cartilage. The degradation of collagen can generate new biochemical markers with the ability to monitor disease progression and facilitate drug development. In addition, collagen can also be used as a biomaterial with excellent properties such as low immunogenicity, biodegradability, biocompatibility, and hydrophilicity. This review not only provides a systematic description of collagen and analyzes the structural characteristics of articular cartilage and the mechanisms of cartilage damage in disease states but also provides a detailed characterization of the biomarkers of collagen production and the role of collagen in cartilage repair, providing ideas and techniques for clinical diagnosis and treatment.

Immunomodulatory functions of TRPM7 and its implications in autoimmune diseases.

An autoimmune disease is an inappropriate response to one's tissues due to a break in immune tolerance and exposure to self-antigens. It often leads to structural and functional damage to organs and systemic disorders. To date, there are no effective interventions to prevent the progression of autoimmune diseases. Hence, there is an urgent need for new treatment targets. TRPM7 is an enzyme-coupled, transient receptor ion channel of the subfamily M that plays a vital role in pathologic and physiologic conditions. While TRPM7 is constitutively activated under certain conditions, it can regulate cell migration, polarization, proliferation and cytokine secretion. However, a growing body of evidence highlights the critical role of TRPM7 in autoimmune diseases, including rheumatoid arthritis, multiple sclerosis and diabetes. Herein, we present (a) a review of the channel kinase properties of TRPM7 and its pharmacological properties, (b) discuss the role of TRPM7 in immune cells (neutrophils, macrophages, lymphocytes and mast cells) and its upstream immunoreactive substances, and (c) highlight TRPM7 as a potential therapeutic target for autoimmune diseases.

Systemic pharmacological verification of Baixianfeng decoction regulating TNF-PI3K-Akt-NF-κB pathway in treating rheumatoid arthritis.

Traditional Chinese medicine has a long history of treating complex diseases, especially for the conditioning of systemic diseases. It has been reported that Baixianfeng (BXF) decoction used to treat rheumatoid arthritis (RA) may be due to its systemic regulatory effect, but the specific mechanism still remains to be elucidated. The research philosophy and methods of systemic pharmacology were used to explore the mechanism of BXF decoction in treating RA in this study. TCMSP database was used to search the ingredients of BXF decoction and screen the ADME parameters. The parameter index was set as OB ≥ 30%, DL ≥ 0.18, HL ≥ 4 h. The targets of the screened compounds were searched and predicted by TCMSP and Target-Prediction platforms. The disease targets of RA were obtained through the DisGeNET, OMIM, and PharmGkb databases. A series of network construction and analysis relied on Cytoscape 3.2.1 software, and the DAVID database was used for pathway enrichment. The adjuvant arthritis rat model was used for the verification of animal experiments to verify the predicted pathway results in terms of pathological phenotype, inflammatory factors, and pathway protein expression. The results showed that the related targets of 81 active ingredients in the drug crossed 56 targets of RA, and these common targets were enriched in 83 significant pathways, among which the TNF signaling pathway had research significance. Animal experiments have proved that BXF decoction was effective in treating adjuvant arthritis rats. The drug relieved the pathological phenotype of rats in dose-dependent. It reduced the serum content of TNF-α and IL-1ß, and reduced the gene expression of TNF-α and IL-6 in spleen tissue. In the cartilage tissue protein of rats, it inhibited the degradation of collagen Ⅱ protein. Further, BXF decoction reduced the activation of p-PI3K, p-Akt, and p-P65 protein, and decreased the overexpression of apoptotic proteins such as cleaved-caspase8 and cleaved-caspase3 in cartilage tissue. Meanwhile, it inhibited the protein expression of MMP9, TNF-α, IL-6, and IL-1ß. In conclusion, this study successfully practiced the combination of systemic pharmacology and experimental verification, and clarified that BXF decoction inhibited the progression of adjuvant arthritis rats through the TNF-PI3K-Akt-NF-κB signal axis. It provides new evidence for the study of the mechanism of BXF decoction in treating RA.

Association of novel MUC16, MAP3K15 and ABCA1 mutation with giant congenital melanocytic nevus.

BACKGROUND: Giant congenital melanocytic nevus (GCMN) is the benign nevomelanocytic proliferation. Mutations in NRAS have been previously detected in GCMN, but mutations in BRAF are generally lacking in the Chinese population. Mutated genes in this disease can estimate the risk of malignant transformation in GCMN. Therefore, it is worth investigating the genetic information of GCMN. METHODS: Here, we presented two cases of GCMN of the upper extremities. The clinical and histological data were analyzed. The whole exome sequencing (WES) was performed to investigate the mutational profile of peripheral venous blood (PB), normal skin (NS), small melanocytic nevus (SMN), deep penetrating and non-penetrating GCMN (dPGCMN and nPGCMN). RESULTS: We showed a reduction in the circumference of involved upper extremities in both patients. The clinical and histopathological data indicated the reduction of adipose tissue associated with the invasion of GCMN. The WES data revealed that MUC16, MAP3K15 and ABCA1 were novel potential candidate genes for the disease as well as biomarkers for predicting malignant transformation. CONCLUSION: The MUC16, MAP3K15 and ABCA1 may serve as novel biomarkers for predicting malignant transformation and targets for the diagnoses and therapy for the GCMN.

Curcumin ameliorates IL-1ß-induced apoptosis by activating autophagy and inhibiting the NF-κB signaling pathway in rat primary articular chondrocytes.

Articular cartilage damage and chondrocyte apoptosis are common features of rheumatoid arthritis and osteoarthritis. Recently, curcumin has been reported to exhibit protective effects on degeneration in articular cartilage diseases. However, the effects and mechanisms of curcumin on articular chondrocyte injury remain to be elucidated. The aim of the present study is to investigate the chondroprotective mechanisms of curcumin on interleukin-1ß (IL-1ß)-induced chondrocyte apoptosis in vitro. The results revealed that IL-1ß decreased cell viability and induced apoptosis in primary articular chondrocytes. Curcumin pretreatment reduced IL-1ß-induced articular chondrocyte apoptosis. In addition, treatment with curcumin increased autophagy in articular chondrocytes and protected against IL-1ß-induced apoptosis. The curcumin-mediated protection against IL-1ß induced apoptosis was abolished when cells were treated with the autophagy inhibitor 3-methyladenine or transfected with Beclin-1 small interfering RNA. Furthermore, IL-1ß stimulation significantly increased the phosphorylation levels of nuclear factor (NF)-κB p65 and glycogen synthase kinase-3ß, and decreased the phosphorylation levels of ß-catenin in articular chondrocytes, and these alterations to the phosphorylation levels were partly reversed by treatment with curcumin. Dual-luciferase and electrophoretic mobility shift assays demonstrated that IL-1ß increased NF-κB p65 promoter activity in chondrocytes, and this was also reversed by curcumin. Pretreatment with the NF-κB inhibitor pyrrolidine dithiocarbamate enhanced the protective effects of curcumin on chondrocyte apoptosis, but Wnt/ß-catenin inhibitor, XAV-939, did not exhibit this effect. Molecular docking and dynamic simulation studies results showed that curcumin could bound to RelA (p65) protein. These results indicate that curcumin may suppress IL-1ß-induced chondrocyte apoptosis through activating autophagy and restraining NF-κB signaling pathway.

Blockade of lncRNA-ASLNCS5088-enriched exosome generation in M2 macrophages by GW4869 dampens the effect of M2 macrophages on orchestrating fibroblast activation.

In hypertrophic scar (HS) formation, the type 2 immune response induces the alternatively activated macrophages (M2), which manipulate fibroblasts to differentiate into myofibroblasts with active biologic functions and proliferation. Myofibroblasts express α-smooth muscle actin (α-SMA) and synthesize and produce additional collagen type I and collagen type III, inducing HS formation. However, studies on the mechanism of M2 macrophage modulation are only based on the recognition of profibrotic factors such as TGF-ß1 secreted by macrophages. The influence of exosomes from M2 macrophages on scar formation is still unknown. Both M2 macrophages and myofibroblasts highly express glutaminases (GLSs). GLS is a critical enzyme in glutaminolysis and is important for M2 macrophage and fibroblast polarization. In this study, we found that in a TGF-ß1-stimulated coculture system, a long noncoding RNA (lncRNA) named lncRNA-ASLNCS5088 was enriched in M2 macrophage-derived exosomes. This lncRNA could be transferred with high efficiency to fibroblasts and acted as an endogenous sponge to adsorb microRNA-200c-3p, resulting in increased GLS and α-SMA expression. Pretreatment with GW4869, which impairs M2 macrophage exosome synthesis, ameliorated these pathologic changes in fibroblasts in vitro. Local injection in the late scar formation period with GW4869 reduced α-SMA+ fibroblasts and alleviated the fibrosis of tissue after wound healing in vivo.-Chen, J., Zhou, R., Liang, Y., Fu, X., Wang, D., Wang, C. Blockade of lncRNA-ASLNCS5088-enriched exosome generation in M2 macrophages by GW4869 dampens the effect of M2 macrophages on orchestrating fibroblast activation.

Acid-sensing ion channel 1a mediates acid-induced pyroptosis through calpain-2/calcineurin pathway in rat articular chondrocytes.

The pyroptosis is a causative agent of rheumatoid arthritis, a systemic autoimmune disease merged with degenerative articular cartilage. Nevertheless, the precise mechanism of extracellular acidosis on chondrocyte pyroptosis is largely unclear. Acid-sensing ion channels (ASICs) belong to an extracellular H+ -activated cation channel family. Accumulating evidence has highlighted activation of ASICs induced by extracellular acidosis upregulate calpain and calcineurin expression in arthritis. In the present study, to investigate the expression and the role of acid-sensing ion channel 1a (ASIC1a), calpain, calcineurin, and NLRP3 inflammasome proteins in regulating acid-induced articular chondrocyte pyroptosis, primary rat articular chondrocytes were subjected to different pH, different time, and different treatments with or without ASIC1a, calpain-2, and calcineurin, respectively. Initially, the research results showed that extracellular acidosis-induced the protein expression of ASIC1a in a pH- and time-dependent manner, and the messenger RNA and protein expressions of calpain, calcineurin, NLRP3, apoptosis-associated speck-like protein, and caspase-1 were significantly increased in a time-dependent manner. Furthermore, the inhibition of ASIC1a, calpain-2, or calcineurin, respectively, could decrease the cell death accompanied with the decreased interleukin-1ß level, and the decreased expression of ASIC1a, calpain-2, calcineurin, and NLRP3 inflammasome proteins. Taken together, these results indicated the activation of ASIC1a induced by extracellular acidosis could trigger pyroptosis of rat articular chondrocytes, the mechanism of which might partly be involved with the activation of calpain-2/calcineurin pathway.

Pharmacokinetics and bioequivalence of two oral formulations of canagliflozin after single-dose administration in healthy Chinese subjects
.

OBJECTIVE: This study was conducted to evaluate the pharmacokinetic properties and bioequivalence of two oral formulations of canagliflozin: a newly developed generic formulation (test) and a branded formulation (reference). MATERIALS AND METHODS: A randomized, open-label, two-way crossover study was conducted in 55 healthy Chinese subjects. They were randomized to receive a single oral dose of 100 mg of test or reference canagliflozin tablets according to an open crossover design under fasting and fed states. Plasma canagliflozin concentrations were determined by liquid chromatography-tandem mass spectrometry, and the pharmacokinetic parameters maximum concentration (Cmax) and area under the concentration-time curve (AUC0-t and AUC0-∞) were used to evaluate bioequivalence. RESULTS: The geometric mean ratio 90% confidence intervals for fasting Cmax, AUC0-t, and AUC0-∞ were 85.14 - 114.40%, 102.14 - 106.51%, and 102.21 - 106.85%, respectively, and fed Cmax, AUC0-t, and AUC0-∞ were 90.15 - 107.17%, 97.38 - 102.19%, and 96.78 - 101.92%, respectively. The mean values of tmax were prolonged in the test compared with the reference formulations. In addition, the mean values of tmax and Cmax for both formulations were significantly different under fed compared with fasting conditions, while there was no significant difference in AUC0-t or AUC0-∞. CONCLUSION: The two types of canagliflozin tablets were bioequivalent under both fasting and fed states, and both were generally well tolerated.

Effects of autophagy on apoptosis of articular chondrocytes in adjuvant arthritis rats.

Rheumatoid arthritis (RA) is a chronic, systemic autoimmune disease that eventually leads to joint deformities and loss of joint function. Previous studies have demonstrated a close relationship between autophagy and the development of RA. Although autophagy and apoptosis are two different forms of programmed death, the relationship between them in relation to RA remains unclear. In this study, we explored the effect of autophagy on apoptosis of articular chondrocytes in vivo and in vitro. Adjuvant arthritis (AA) and acid-induced primary articular chondrocyte apoptosis were used as in vivo and in vitro models, respectively. Articular chondrocyte autophagy and apoptosis were both observed dynamically in AA rat articular cartilage at different stages (15 days, 25 days and 35 days). Moreover, chondrocyte apoptosis and articular cartilage injury in AA rats were increased by the autophagy inhibitor 3-methyladenine (3-MA) and decreased by the autophagy activator rapamycin. In addition, pre-treatment with 3-MA increased acid-induced chondrocyte apoptosis, while pre-treatment with rapamycin reduced acid-induced chondrocyte apoptosis in vitro. These results suggest that autophagy might be a potential target for the treatment of RA.

ß-Estradiol Protects Against Acidosis-Mediated and Ischemic Neuronal Injury by Promoting ASIC1a (Acid-Sensing Ion Channel 1a) Protein Degradation.

Background and Purpose- Sex differences in the incidence and outcome of stroke have been well documented. The severity of stroke in women is, in general, significantly lower than that in men, which is mediated, at least in part, by the protective effects of ß-estradiol. However, the detailed mechanisms underlying the neuroprotection by ß-estradiol are still elusive. Recent studies have demonstrated that activation of ASIC1a (acid-sensing ion channel 1a) by tissue acidosis, a common feature of brain ischemia, plays an important role in ischemic brain injury. In the present study, we assessed the effects of ß-estradiol on acidosis-mediated and ischemic neuronal injury both in vitro and in vivo and explored the involvement of ASIC1a and underlying mechanism. Methods- Cultured neurons and NS20Y cells were subjected to acidosis-mediated injury in vitro. Cell viability and cytotoxicity were measured by methylthiazolyldiphenyl-tetrazolium bromide and lactate dehydrogenase assays, respectively. Transient (60 minutes) focal ischemia in mice was induced by suture occlusion of the middle cerebral artery in vivo. ASIC currents were recorded using whole-cell patch-clamp technique while intracellular Ca2+ concentration was measured with fluorescence imaging using Fura-2. ASIC1a expression was detected by Western blotting and quantitative real-time polymerase chain reaction. Results- Treatment of neuronal cells with ß-estradiol decreased acidosis-induced cytotoxicity. ASIC currents and acid-induced elevation of intracellular Ca2+ were all attenuated by ß-estradiol treatment. In addition, we showed that ß-estradiol treatment reduced ASIC1a protein expression, which was mediated by increased protein degradation, and that estrogen receptor α was involved. Finally, we showed that the level of ASIC1a protein expression in brain tissues and the degree of neuroprotection by ASIC1a blockade were lower in female mice, which could be attenuated by ovariectomy. Conclusions- ß-estradiol can protect neurons against acidosis-mediated neurotoxicity and ischemic brain injury by suppressing ASIC1a protein expression and channel function. Visual Overview- An online visual overview is available for this article.