Mechanosensitive TRPV4 is required for crystal-induced inflammation

A comprehensive analysis of TRP-related gene signature, and immune infiltration in patients with colorectal cancer

BACKGROUND

Transient receptor potential (TRP) channels are involved in the development and progression of tumors. However, their role in colorectal cancer (CRC) remains unclear, and this study aims to investigate the role of TRP-related genes in CRC.

METHODS

Data was obtained from The Cancer Genome Atlas (TCGA) database, and analyses were conducted on the GSE14333 and GSE38832 datasets to assess the prognosis and mark TRP-related genes (TRGs). Subsequently, clustering analysis and immune infiltration analysis were performed to explore the relevant TRGs. In vitro validation of key TRGs' gene and protein expression was conducted using human colon cancer cells.

RESULTS

Compared to normal tissues, 8 TRGs were significantly upregulated in CRC, while 11 were downregulated. TRPA1 was identified as a protective prognostic factor, whereas TRPM5 (HR = 1.349), TRPV4 (HR = 1.289), and TRPV3 (HR = 1.442) were identified as prognostic risk factors. Receiver operating characteristic (ROC) curves and Kaplan-Meier (KM) analyses yielded similar results. Additionally, lower expression of TRPA1 and higher expression of TRPV4 and TRPM5 were negatively correlated with patient prognosis, and experimental validation confirmed the underexpression of TRPA1 and overexpression of TRPV4 and TRPM5 in CRC cell lines.

CONCLUSION

This study identifies a TRP channel-related prognosis in CRC, providing a novel approach to stratifying CRC prognosis.

Recent advances in the treatment of gout with NLRP3 inflammasome inhibitors

Gout is an autoinflammatory disorder characterized by the accumulation of monosodium urate crystals in joints and other tissues, representing the predominant type of inflammatory arthritis with a notable prevalence and propensity for severe outcomes. The NLRP3 inflammasome, a member of the pyrin domain-containing NOD-like receptor family, exerts a substantial impact on both innate and adaptive immune responses and serves as a pivotal factor in the pathogenesis of gout. In recent years, there has been significant academic and industrial interest in the development of NLRP3-targeted small molecule inhibitors as a promising therapeutic approach for gout. To assess the advancements in NLRP3 inflammasome inhibitors for gout treatment, this review offers a comprehensive analysis and evaluation of current clinical candidates and other inhibitors targeting NLRP3 inflammasome from a chemical structure standpoint, with the goal of identifying more efficacious options for clinical management of gout.

Piper longum L. ameliorates gout through the MAPK/PI3K-AKT pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Gout, a painful joint disease with a prevalence ranging from 0.86% to 2.2% in China over the past decade. Traditional medicine has long utilized the medicinal and edible Piper longum L. (PL) fruit spikes for treating gout and other joint conditions like rheumatoid arthritis. However, the exact mechanisms behind its effectiveness remain unclear.

AIM OF THE STUDY

This study aimed to investigate the potential of alcoholic extracts from PL fruit spikes as a safe and effective treatment for gout. We used a combined network pharmacology and experimental validation approach to evaluate the mechanisms behind the anti-gout properties of PL.

MATERIALS AND METHODS

UPLC-Q/TOF-MS analysis determined the major components of PL. Subsequently, network pharmacology analysis predicted potential molecular targets and related signaling pathways for the anti-gout activity of PL. Molecular docking simulations further explored the interactions between PL compounds and proteins and characterized the properties of potential bioactive secondary metabolites. Mouse models of air pouch inflammation and hyperuricemia were further established, and the anti-gout mechanism of PL was confirmed by examining the expression of proteins related to the MAPK and PI3K-AKT pathways in the tissue.

RESULTS

Our analysis revealed 220 bioactive secondary metabolites within PL extracts. Network pharmacology and molecular docking results indicated that these metabolites primarily combat gout by modulating the PI3K-AKT and MAPK signaling pathways. In vivo experiments have also proven that PL at a dose of 100 mg/kg can optimally reduce acute inflammation of gout and kidney damage caused by high uric acid. The anti-gout mechanism involves the PI3K-AKT/MAPK signaling pathway and its downstream NF-κB pathway.

CONCLUSION

This study provides compelling evidence for PL's therapeutic potential in gout management by modulating key inflammatory pathways. The findings offer a strong foundation for future clinical exploration of PL as a gout treatment option.

Transient receptor potential melastatin 8 contributes to the interleukin-33-mediated cold allodynia in a mouse model of neuropathic pain

ABSTRACT

Cold allodynia is a common complaint of patients suffering from neuropathic pain initiated by peripheral nerve injury. However, the mechanisms that drive neuropathic cold pain remain elusive. In this study, we show that the interleukin (IL)-33/ST2 signaling in the dorsal root ganglion (DRG) is a critical contributor to neuropathic cold pain by interacting with the cold sensor transient receptor potential melastatin 8 (TRPM8). By using the St2-/- mice, we demonstrate that ST2 is required for the generation of nociceptor hyperexcitability and cold allodynia in a mouse model of spared nerve injury (SNI). Moreover, the selective elimination of ST2 function from the Nav1.8-expressing nociceptor markedly suppresses SNI-induced cold allodynia. Consistent with the loss-of-function studies, intraplantar injection of recombinant IL-33 (rIL-33) is sufficient to induce cold allodynia. Mechanistically, ST2 is co-expressed with TRPM8 in both mouse and human DRG neurons and rIL-33-induced Ca2+ influx in mouse DRG neurons through TRPM8. Co-immunoprecipitation assays further reveal that ST2 interacts with TRPM8 in DRG neurons. Importantly, rIL-33-induced cold allodynia is abolished by pharmacological inhibition of TRPM8 and genetic ablation of the TRPM8-expressing neurons. Thus, our findings suggest that the IL-33/ST2 signaling mediates neuropathic cold pain through downstream cold-sensitive TRPM8 channels, thereby identifying a potential analgesic target for the treatment of neuropathic cold pain.

LPS exacerbates TRPV4-mediated itch through the intracellular TLR4-PI3K signalling

Pruritus is often accompanied with bacterial infections, but the underlying mechanism is not fully understood. Although previous studies revealed that lipopolysaccharides (LPS) could directly activate TRPV4 channel and TRPV4 is involved in the generation of both acute itch and chronic itch, whether and how LPS affects TRPV4-mediated itch sensation remains unclear. Here, we showed that LPS-mediated TRPV4 sensitization exacerbated GSK101-induced scratching behaviour in mice. Moreover, this effect was compromised in TLR4-knockout mice, suggesting LPS acted through a TLR4-dependent mechanism. Mechanistically, LPS enhanced GSK101-evoked calcium influx in mouse ear skin cells and HEK293T cells transfected with TRPV4. Further, LPS sensitized TRPV4 channel through the intracellular TLR4-PI3K-AKT signalling. In summary, our study found a modulatory role of LPS in TRPV4 function and highlighted the TLR4-TRPV4 interaction in itch signal amplification.

Sirt1 inhibits macrophage polarization and inflammation in gouty arthritis by inhibiting the MAPK/NF-κB/AP-1 pathway and activating the Nrf2/HO-1 pathway

OBJECTIVE AND DESIGN

To elucidate Sirt1's role in gouty arthritis inflammation and its potential mechanisms.

MATERIAL

Constructed murine models of gouty arthritis and conducted THP-1 cell experiments.

TREATMENT

1 mg of MSU crystals injected into mice ankle joints for a 72-h intervention. After a 3-h pre-treatment with Sirt1-specific inhibitor (EX527) and agonist (SRT2104), inflammation was induced for 21 h using lipopolysaccharide (LPS) plus MSU crystals.

METHODS

We assessed gouty arthritis severity through joint inflammation index, swelling, and hematoxylin and eosin (H&E) staining, and measured CD68 mononuclear macrophages and Sirt1 expression in synovial tissue via immunohistochemistry. ELISA, NO assay, RT-qPCR, Flow cytometry, and Western blot were utilized to examine macrophage inflammatory factors, polarization, reactive oxygen species(ROS), MAPK/NF-κB/AP-1 and Nrf2/HO-1 pathways proteins.

RESULTS

Significant joint swelling, synovial tissue edema, and inflammatory cell infiltration were observed. CD68 mononuclear macrophages and Sirt1 expression were elevated in synovium. Sirt1 activation decreased inflammatory factors, M1 polarization, and ROS generation. Sirt1 activation reduced p38/JNK phosphorylation, thereby inhibiting downstream NF-κB p65/AP-1 and enhancing Nrf2/HO-1, thus suppressing inflammation.

CONCLUSIONS

Sirt1 alleviates M1 macrophage polarization and inflammation in gouty arthritis by inhibiting the MAPK/NF-κB/AP-1 pathway and activating the Nrf2/HO-1 pathway. Thus, activating Sirt1 may provide a new therapeutic target for gouty arthritis.

Pathology of pain and its implications for therapeutic interventions

Pain is estimated to affect more than 20% of the global population, imposing incalculable health and economic burdens. Effective pain management is crucial for individuals suffering from pain. However, the current methods for pain assessment and treatment fall short of clinical needs. Benefiting from advances in neuroscience and biotechnology, the neuronal circuits and molecular mechanisms critically involved in pain modulation have been elucidated. These research achievements have incited progress in identifying new diagnostic and therapeutic targets. In this review, we first introduce fundamental knowledge about pain, setting the stage for the subsequent contents. The review next delves into the molecular mechanisms underlying pain disorders, including gene mutation, epigenetic modification, posttranslational modification, inflammasome, signaling pathways and microbiota. To better present a comprehensive view of pain research, two prominent issues, sexual dimorphism and pain comorbidities, are discussed in detail based on current findings. The status quo of pain evaluation and manipulation is summarized. A series of improved and innovative pain management strategies, such as gene therapy, monoclonal antibody, brain-computer interface and microbial intervention, are making strides towards clinical application. We highlight existing limitations and future directions for enhancing the quality of preclinical and clinical research. Efforts to decipher the complexities of pain pathology will be instrumental in translating scientific discoveries into clinical practice, thereby improving pain management from bench to bedside.

Phenolic acids from Chicory roots ameliorate dextran sulfate sodium-induced colitis in mice by targeting TRP signaling pathways and the gut microbiota

BACKGROUND

Inflammatory bowel disease (IBD) is a type of immune-mediated condition associated with intestinal homeostasis. Our preliminary studies disclosed that Cichorium intybus L., a traditional medicinal plant, also known as Chicory in Western countries, contained substantial phenolic acids displaying significant anti-inflammatory activities. We recognized the potential of harnessing Chicory for the treatment of IBD, prompting a need for in-depth investigation into the underlying mechanisms.

METHODS

On the third day, mice were given 100, 200 mg/kg of total phenolic acids (PA) from Chicory and 200 mg/kg of sulfasalazine (SASP) via gavage, while dextran sodium sulfate (DSS) concentration was 2.5 % for one week. The study measured and evaluated various health markers including body weight, disease activity index (DAI), colon length, spleen index, histological score, serum concentrations of myeloperoxidase (MPO), nitric oxide (NO), superoxide dismutase (SOD), lipid oxidation (MDA), and inflammatory factors. We evaluated the TRP family and the NLRP3 inflammatory signaling pathways by Western blot, while 16S rDNA sequencing was used to track the effects of PA on gut microbes.

RESULTS

It was shown that PA ameliorated the weight loss trend, attenuated inflammatory damage, regulated oxidative stress levels, and repaired the intestinal barrier in DSS mice. Analyses of Western blots demonstrated that PA suppressed what was expressed of transient receptor potential family TRPV4, TRPA1, and the expression of NLRP3 inflammatory signaling pathway, NLRP3 and GSDMD. In addition, PA exerted therapeutic effects on IBD by regulating gut microbiota richness and diversity. Meanwhile, the result of the KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway enrichment analysis showed that gut microbiota was mainly related to Membrane Transport, Replication and Repair, Carbohydrate Metabolism and Amino Acid Metabolism.

CONCLUSION

PA derived from Chicory may have therapeutic effects on IBD by regulating the TRPV4/NLRP3 signaling pathway and gut microbiome. This study provides new insights into the effects of phenolic acids from Chicory on TRP ion channels and gut microbiota, revealing previously unexplored modes of action.

Metabolite-derived damage-associated molecular patterns in immunological diseases

Damage-associated molecular patterns (DAMPs) are typically derived from the endogenous elements of necrosis cells and can trigger inflammatory responses by activating DAMPs-sensing receptors on immune cells. Failure to clear DAMPs may lead to persistent inflammation, thereby contributing to the pathogenesis of immunological diseases. This review focuses on a newly recognized class of DAMPs derived from lipid, glucose, nucleotide, and amino acid metabolic pathways, which are then termed as metabolite-derived DAMPs. This review summarizes the reported molecular mechanisms of these metabolite-derived DAMPs in exacerbating inflammation responses, which may attribute to the pathology of certain types of immunological diseases. Additionally, this review also highlights both direct and indirect clinical interventions that have been explored to mitigate the pathological effects of these DAMPs. By summarizing our current understanding of metabolite-derived DAMPs, this review aims to inspire future thoughts and endeavors on targeted medicinal interventions and the development of therapies for immunological diseases.

CXCL5 activates CXCR2 in nociceptive sensory neurons to drive joint pain and inflammation in experimental gouty arthritis

Gouty arthritis evokes joint pain and inflammation. Mechanisms driving gout pain and inflammation remain incompletely understood. Here we show that CXCL5 activates CXCR2 expressed on nociceptive sensory neurons to drive gout pain and inflammation. CXCL5 expression was increased in ankle joints of gout arthritis model mice, whereas CXCR2 showed expression in joint-innervating sensory neurons. CXCL5 activates CXCR2 expressed on nociceptive sensory neurons to trigger TRPA1 activation, resulting in hyperexcitability and pain. Neuronal CXCR2 coordinates with neutrophilic CXCR2 to contribute to CXCL5-induced neutrophil chemotaxis via triggering CGRP- and substance P-mediated vasodilation and plasma extravasation. Neuronal Cxcr2 deletion ameliorates joint pain, neutrophil infiltration and gait impairment in model mice. We confirmed CXCR2 expression in human dorsal root ganglion neurons and CXCL5 level upregulation in serum from male patients with gouty arthritis. Our study demonstrates CXCL5-neuronal CXCR2-TRPA1 axis contributes to gouty arthritis pain, neutrophil influx and inflammation that expands our knowledge of immunomodulation capability of nociceptive sensory neurons.

Microglial Nrf2/HO-1 signaling gates remifentanil-induced hyperalgesia via suppressing TRPV4-mediated M1 polarization

Remifentanil-induced hyperalgesia (RIH) represents a significant clinical challenge due to the widespread use of opioids in pain management. However, the molecular and cellular mechanisms underlying RIH remain elusive. This study aimed to unravel the role of spinal cord microglia, focusing on the Nrf2/HO-1 signaling pathway and TRPV4 channels in the development of RIH. We used both in vivo and in vitro models to investigate the activation state of spinal cord microglia, the expression of TRPV4 channels, and the modulation of the Nrf2/HO-1 pathway under remifentanil exposure. In addition, we evaluated the potential therapeutic effects of dexmedetomidine, a perioperative α2-adrenergic agonist, on RIH and its related molecular pathways. Our results revealed a prominent role of spinal cord microglia in RIH, demonstrating an apparent microglial M1 polarization and increased TRPV4 channel expression. A notable observation was the downregulation of the Nrf2/HO-1 pathway, which was associated with increased neuroinflammation and mechanical allodynia. By upregulating or overexpressing Nrf2, we confirmed its ability to inhibit TRPV4 and thereby attenuate RIH-associated mechanical allodynia, M1 polarization, and neuroinflammation. Encouragingly, dexmedetomidine demonstrated therapeutic potential by positively modulating the Nrf2-TRPV4 nexus, attenuating mechanical allodynia, and reducing microglial inflammation. Our research highlights the critical role of spinal cord microglia in RIH mediated by the Nrf2-TRPV4 axis. The ability of dexmedetomidine to modulate this axis suggests its potential as an adjunctive therapy to remifentanil in mitigating RIH. Further studies are imperative to explore the broader implications and practical applicability of our findings.

Establishing an ANO1-Based Cell Model for High-Throughput Screening Targeting TRPV4 Regulators

Transient receptor potential vanilloid 4 (TRPV4) is a widely expressed cation channel that plays an important role in many physiological and pathological processes. However, most TRPV4 drugs carry a risk of side effects. Moreover, existing screening methods are not suitable for the high-throughput screening (HTS) of drugs. In this study, a cell model and HTS method for targeting TRPV4 channel drugs were established based on a calcium-activated chloride channel protein 1 Anoctamin 1 (ANO1) and a double mutant (YFP-H148Q/I152L) of the yellow fluorescent protein (YFP). Patch-clamp experiments and fluorescence quenching kinetic experiments were used to verify that the model could sensitively detect changes in intracellular Ca2+ concentration. The functionality of the TRPV4 cell model was examined through temperature variations and different concentrations of TRPV4 modulators, and the performance of the model in HTS was also evaluated. The model was able to sensitively detect changes in the intracellular Ca2+ concentration and also excelled at screening TRPV4 drugs, and the model was more suitable for HTS. We successfully constructed a drug cell screening model targeting the TRPV4 channel, which provides a tool to study the pathophysiological functions of TRPV4 in vitro.

Gut-immunity-joint axis: a new therapeutic target for gouty arthritis

Gouty arthritis (GA) is an inflammatory disease characterized by pain. The primary goal of current treatment strategies during GA flares remains the reduction of inflammation and pain. Research suggests that the gut microbiota and microbial metabolites contribute to the modulation of the inflammatory mechanism associated with GA, particularly through their effect on macrophage polarization. The increasing understanding of the gut-joint axis emphasizes the importance of this interaction. The primary objective of this review is to summarize existing research on the gut-immune-joint axis in GA, aiming to enhance understanding of the intricate processes and pathogenic pathways associated with pain and inflammation in GA, as documented in the published literature. The refined comprehension of the gut-joint axis may potentially contribute to the future development of analgesic drugs targeting gut microbes for GA.

Nod-like receptors in inflammatory arthritis

Nod-like receptors (NLRs) are innate immune receptors that play a key role in sensing components from pathogens and from damaged cells or organelles. NLRs form signaling complexes that can lead to activation of transcription factors or effector caspases - by means of inflammasome activation -Inflammatory arthritis (IA) culminating in promoting inflammation. An increasing body of research supports the role of NLRs in driving pathogenesis of IA, a collection of diseases that include rheumatoid arthritis (RA), psoriatic arthritis (PsA), ankylosing spondylitis, and pediatric arthritis. In this review, we briefly discuss the main drivers of IA diseases and dive into the evidence for - and against - various NLRs in driving these diseases. We also review the studies examining the use of NLR and inflammasome inhibitors as potential therapies for IA.

Activation of Nrf2 antioxidant signaling alleviates gout arthritis pain and inflammation

Excessive deposition of monosodium urate (MSU) crystal in the joint results in gout arthritis, which triggers severe pain and affects life quality. Oxidative stress is a pivotal mechanism that contributes to etiology of gout pain and inflammation. Here we investigated whether activating Nrf2, which plays important roles in regulating endogenous antioxidant response, would attenuate gout arthritis via promoting antioxidant signaling in joint tissues. Gout arthritis model was established by intra-articular injection of MSU (500 μg/ankle) into the right ankle joint of mouse. Pharmacologically activating Nrf2 by activator oltipraz (50, 100 or 150 mg/kg, intraperitoneal) at 1 h before and 5, 23, 47 h after model establishment dose-dependently inhibited joint inflammation, mechanical and heat hypersensitivities in model mice. Oltipraz (100 mg/kg) reversed gait impairments without altering locomotor activity and reduced neutrophil infiltrations in ankle joints. In vitro studies revealed oltipraz (25 μM) inhibited MSU-induced ROS production in mouse macrophages and improved mitochondrial bioenergetics impairments caused by MSU. In vivo ROS imaging combined with biochemical assays confirmed the antioxidant effects of oltipraz on model mice. Nrf2 activation inhibited pro-inflammatory cytokine overproduction in ankle joint and attenuated the overexpression and enhancement in TRPV1 channel in DRG neurons innervating hind limb. Therapeutic effects of oltipraz were abolished by inhibiting Nrf2 or in Nrf2 knockout mice. These results suggest pharmacologically activating Nrf2 alleviates gout pain, gait impairments, inflammation and peripheral sensitization via Nrf2-dependent antioxidant mechanism. Targeting Nrf2 may represent a novel treatment option for gout arthritis.

KCNN4 links PIEZO-dependent mechanotransduction to NLRP3 inflammasome activation

Immune cells sense the microenvironment to fine-tune their inflammatory responses. Patients with cryopyrin-associated periodic syndrome (CAPS), caused by mutations in the NLRP3 gene, develop autoinflammation triggered by nonantigenic cues such as from the environment. However, the underlying mechanisms are poorly understood. Here, we uncover that KCNN4, a calcium-activated potassium channel, links PIEZO-mediated mechanotransduction to NLRP3 inflammasome activation. Yoda1, a PIEZO1 agonist, lowered the threshold for NLRP3 inflammasome activation. PIEZO-mediated sensing of stiffness and shear stress increased NLRP3-dependent inflammation. Myeloid-specific deletion of PIEZO1/2 protected mice from gouty arthritis. Mechanistically, activation of PIEZO1 triggers calcium influx, which activates KCNN4 to evoke potassium efflux and promotes NLRP3 inflammasome activation. Activation of PIEZO signaling was sufficient to activate the inflammasome in cells expressing CAPS-causing NLRP3 mutants via KCNN4. Last, pharmacological inhibition of KCNN4 alleviated autoinflammation in cells of patients with CAPS and in mice bearing a CAPS mutation. Thus, PIEZO-dependent mechanical inputs boost inflammation in NLRP3-dependent diseases, including CAPS.

Effects of spray cryotherapy on cough receptors and airway microenvironment in a canine model of chronic bronchitis

The aim of this study was to explore the effects of spray cryotherapy (SCT) on cough receptors and airway microenvironment in a canine model of chronic bronchitis. We examined the expression of transient receptor potential vanilloid 1/4 (TRPV1/4) and the neuropeptides substance P (SP) and calcitonin gene-related peptide (CGRP) at the gene and protein levels before and after SCT. In addition, we explored whether TRPV1/4 could regulate inflammatory factors via mediator adenosine triphosphate (ATP). The levels of ATP and cytokines in alveolar lavage fluid and cell supernatant were measured using ELISA. SCT effectively downregulated the expression of TRPV1/4 and SP/CGRP in canine airway tissues with chronic bronchitis and reduced the levels of inflammatory mediators and cytokines that affect cough receptor sensitivity, achieving cough relief. TRPV1/4 - ATP - inflammatory cytokines axis has been demonstrated at the cellular level, which in turn modulate the milieu of the airways and promote the formation of a cough feedback loop. Our study has fully revealed the specific mechanism of SCT in treating cough in a canine model of chronic bronchitis, providing a solid theoretical basis for future clinical treatment.

Association between the dietary inflammatory index and gout in the National Health and Nutrition Examination Survey 2007-2018

Objective

The aim of our study was to investigate whether the Dietary Inflammatory Index (DII) correlated with gout in American adults.

Method

The study used data from the 2007-2018 National Health and Nutrition Examination Survey, with 27,710 adults participating. Initially, multivariable analysis was performed, with controls for covariates, to assess the link of DII and gout. Then, restricted cubic splines (RCS) were applied to model the nonlinear relationship of DII and gout. Furthermore, propensity score matching (PSM) as a further study of potential relationships was established. Eventually, subgroup analysis was performed.

Result

Participants within the highest DII quartile would be more susceptible to increased risk of gout in the univariate regression model (Q4 vs. Q1, OR = 1.31, CI: 1.05-1.63). Additionally, a positive correlation was detected between gout risk and DII after adjusting on drinking, smoking, gender, race, age, and BMI. Based on RCS analysis, we observed that the risk of gout raised sharply as DII values increased, then flattened, and increased sharply again when the DII was greater than approximately 2.5. After performing the PSM, it was observed that DII correlated in a positive way to the presence of gout on a fully adjusted multivariable model. Subgroup analysis revealed that the link of DII and gout showed no statistical significance in females, blacks, Mexicans, nor in the population that smoked.

Conclusion

Greater degrees of pro-inflammation correlate with a higher risk of gout and might be a predisposing factor for gout. Hence, tactics fostering an anti-inflammatory diet for preventing and improving gout in adults should be regarded.

The value of preoperative neutrophil/lymphocyte ratio in predicting the severity of cholecystolithiasis with cholecystitis in elderly patients

BACKGROUND

This study aims to assess the effectiveness of neutrophil/lymphocyte ratio (NLR) and C-reactive protein (CRP) in diagnosing cholecystolithiasis with cholecystitis in elderly patients. Additionally, the study seeks to determine the predictive value of preoperative NLR in determining the severity of the condition in this population.

METHODS

This study is a retrospective cohort study, including 160 elderly patients with cholecystolithiasis with cholecystitis (45 cases of simple cholecystitis, 58 cases of suppurative cholecystitis, 57 cases of gangrenous cholecystitis) and 60 cases of normal gallbladder histology. The study collected clinical data of the patients detected the preoperative CRP content, neutrophil, and lymphocyte levels through blood routine tests, and calculated the NLR value. The diagnostic value of NLR and CRP was determined by using the Receiver Operating Characteristic Curve (ROC), and the optimal value of preoperative NLR related to the severity of elderly patients with cholecystolithiasis with cholecystitis was identified.

RESULTS

This study found that for elderly patients with cholecystolithiasis with cholecystitis, preoperative NLR and CRP levels can be used to distinguish the condition. The critical value for NLR was found to be 2.995 (95% CI, 0.9465-0.9853; P < 0.001) with an area under the ROC curve of 0.9659, while the critical value for CRP was 13.05 (95% CI, 0.9284-0.9830; P < 0.001) with an area under the ROC curve of 0.9557. Both NLR and CRP were found to have equivalent diagnostic abilities. Additionally, the study found that there were significant differences in neutrophil and lymphocyte levels in elderly patients with different severity levels, with NLR increasing as severity increased (P < 0.001). The study identified cut-off values for preoperative NLR that could distinguish Simple cholecystitis and Purulent cholecystitis, as well as Purulent cholecystitis and Gangrenous cholecystitis in elderly patients with cholecystolithiasis, with respective AUCs of 0.8441 (95% CI: 0.7642-0.9239; P < 0.001) and 0.7886(95% CI: 0.7050-0.8721, P < 0.001), sensitivities of 91.38% and 87.72%, and specificities of 73.33% and 63.79%.

CONCLUSIONS

Preoperative NLR and CRP values can serve as indicators to detect cholecystolithiasis with cholecystitis in elderly patients. Additionally, NLR has been recognized as a potential tool to differentiate the severity of cholecystolithiasis with cholecystitis in the elderly population.

[Sevoflurane alleviates ventilator-induced lung injury in rats by down-regulating the TRPV4/C-PLA2 signaling pathway]

OBJECTIVE

To explore the mechanism underlying the protective effect of sevoflurane against ventilator-induced lung injury (VILI).

METHODS

Thirty-two SD rats were randomized into mechanical ventilation (MV) group, MV+sevoflurane group (MS group), MV+sevoflurane+transient receptor potential vanillate subtype 4 (TRPV4) agonist group (MST group) and MV+ sevoflurane + vehicle group (MSV group). Arachidonic acid (AA) in the lung tissues was quantified with ELISA. TRPV4, cytoplasmic phospholipase A2 (C-PLA2) and myosin light chain kinase (MLCK) protein expressions were detected by Western blotting. Lung injury in the rats was evaluated by assessing MLCK protein expression level, pulmonary permeability index, lung wet/dry ratio, leukocyte count in the bronchoalveolar lavage fluid (BALF), myeloperoxidase content in lung tissue, and histological score of the lungs.

RESULTS

The rats in MV group showed significantly increased TRPV4 and C-PLA2 expression levels in the lung tissues with increased lung permeability and obvious lung inflammation compared with those in the other 3 groups (P < 0.05). No significant differences were found in the parameters associated with lung injuries between MS group and MSV group. Compared with those in MST group, the rats in MS group and MSV group showed significantly reduced AA production and TRPV4 and C-PLA2 expressions in the lungs (P < 0.05) with alleviated lung hyper-permeability and inflammation (P < 0.05).

CONCLUSION

Sevoflurane protects against VILI in rats by down-regulating the TRPV4/C-PLA2 signaling pathway.

Transient receptor potential vanilloid 4 (TRPV4) in neutrophils enhances myocardial ischemia/reperfusion injury

The Ca2+-permeable TRPV4 cation channel is expressed in neutrophils and contributes to myocardial ischemia/reperfusion injury. Here we tested the hypotheses that TRPV4 promotes neutrophil activation and subsequently aggregates myocardial ischemia/reperfusion injury. TRPV4 protein was confirmed in neutrophils, and its function was assessed by the current and intracellular Ca2+ concentration elevations evoked by TRPV4 agonists. Furthermore, TRPV4 agonists dose-dependently promoted migration toward fMLP, reactive oxygen species production, and myeloperoxidase release, which were prevented by pretreatment with a selective TRPV4 antagonist, in neutrophils from TRPV4 knockout mice, Ca2+-free medium, or BAPTA-AM + Ca2+-free medium. Blockade of TRPV4 also inhibited the effects of commonly used neutrophil activators fMLP and PMA. Mechanically, TRPV4 regulated neutrophil activation, particularly reactive oxygen species production, by affecting PKCα, P38, and AKT via Ca2+ signaling. In addition, isolated hearts infused with neutrophils from wild-type mice showed additional myocardial ischemia/reperfusion injuries but not those infused with TRPV4 knockout. Our study reveals that TRPV4-mediated neutrophil activation enhances myocardial ischemia/reperfusion injury, and it might be a novel therapeutic target for myocardial ischemia/reperfusion injury and other neutrophil-mediated inflammatory diseases.

Multimodal roles of transient receptor potential channel activation in inducing pathological tissue scarification

Transient receptor potential (TRP) channels are a class of transmembrane proteins that can sense a variety of physical/chemical stimuli, participate in the pathological processes of various diseases and have attracted increasing attention from researchers. Recent studies have shown that some TRP channels are involved in the development of pathological scarification (PS) and directly participate in PS fibrosis and re-epithelialization or indirectly activate immune cells to release cytokines and neuropeptides, which is subdivided into immune inflammation, fibrosis, pruritus and mechanical forces increased. This review elaborates on the characteristics of TRP channels, the mechanism of PS and how TRP channels mediate the development of PS, summarizes the important role of TRP channels in the different pathogenesis of PS and proposes that therapeutic strategies targeting TRP will be important for the prevention and treatment of PS. TRP channels are expected to become new targets for PS, which will make further breakthroughs and provide potential pharmacological targets and directions for the in-depth study of PS.

Electroacupuncture improves gout arthritis pain via attenuating ROS-mediated NLRP3 inflammasome overactivation

BACKGROUND

Gout results from disturbed uric acid metabolism, which causes urate crystal deposition in joints and surrounding tissues. Gout pain management is largely limited to colchicine and nonsteroidal anti-inflammatory drugs. Constant usage of these medications leads to severe side effects. We previously showed electroacupuncture (EA) is effective for relieving pain in animal model of gout arthritis. Here we continued to study the mechanisms underlying how EA alleviates gout pain.

METHODS

Monosodium urate was injected into ankle joint to establish gout arthritis model in mice. EA or sham EA was applied at ST36 and BL60 acupoints of model animals. Biochemical assays, immunostaining, live cell Ca²⁺ imaging and behavioral assays were applied.

RESULTS

Model mice displayed obvious mechanical allodynia, accompanied with gait impairments. EA attenuated mechanical hypersensitivities and improved gait impairments. EA reduced the overexpression of NLRP3 inflammasome signaling molecules in ankle joints of model animals. EA-induced anti-allodynia, as well as inhibition on NLRP3 inflammasome, were mimicked by antagonizing but abolished by activating NLRP3 inflammasome via pharmacological methods. EA attenuated oxidative stress, an upstream signaling of NLRP3 inflammasome in ankle joints of model mice. Exogenously increasing oxidative stress abolished EA's inhibitory effect on NLRP3 inflammasome and further reversed EA's anti-allodynic effect. EA reduced neutrophil infiltrations in ankle joint synovium, a major mechanism contributing to oxidative stress in gout. Pharmacological blocking NLRP3 inflammasome or EA reduced TRPV1 channel overexpression in dorsal root ganglion (DRG) neurons. Ca²⁺ imaging confirmed that EA could reduce functional enhancement in TRPV1 channel in DRG neurons during gout.

CONCLUSIONS

Our results demonstrate that EA reduces gout pain possibly through suppressing ROS-mediated NLRP3 inflammasome activation in inflamed ankle joints and TRPV1 upregulation in sensory neurons, supporting EA as a treatment option for gout pain.

New drug targets for the treatment of gout arthritis: what's new?

INTRODUCTION

Gout arthritis (GA) is an intermittent inflammatory disease affecting approximately 10% of the worldwide population. Symptomatic phases (acute flares) are timely spaced by asymptomatic periods. During an acute attack, redness, joint swelling, limited movement, and excruciating pain are common symptoms. However, the current available therapies are not fully effective in reducing symptoms and offer numerous side effects. Therefore, unveiling new drug targets and effector molecules are required in developing novel GA therapeutics.

AREAS COVERED

This review discusses the pathophysiological mechanisms of GA and explores potential pharmacological targets to ameliorate disease outcome. In addition, we listed promising pre-clinical studies demonstrating effector molecules with therapeutical potential. Among those, we emphasized the importance of natural products, including traditional Chinese medicine formulas and their multitarget mechanisms of action.

EXPERT OPINION

In our search, we observed that there is a massive gap between pre-clinical and clinical knowledge. Only a minority (4.4%) of clinical trials aimed to intervene by applying natural products or current hot targets described herein. In this sense, we envisage four possibilities for GA therapeutics, which include the repurposing of existing therapies, ALX/FPR2 agonism for improvement in disease outcome, the use of multitarget drugs (e.g. natural products), and targeting the neuroinflammatory component of GA.

Immune and inflammatory mechanisms and therapeutic targets of gout: An update

Gout is an autoimmune disease characterized by acute or chronic inflammation and damage to bone joints induced due to the precipitation of monosodium urate (MSU) crystals. In recent years, with the continuous development of animal models and ongoing clinical investigations, more immune cells and inflammatory factors have been found to play roles in gouty inflammation. The inflammatory network involved in gout has been discovered, providing a new perspective from which to develop targeted therapy for gouty inflammation. Studies have shown that neutrophil macrophages and T lymphocytes play important roles in the pathogenesis and resolution of gout, and some inflammatory cytokines, such as those in the interleukin-1 (IL-1) family, have been shown to play anti-inflammatory or proinflammatory roles in gouty inflammation, but the mechanisms underlying their roles are unclear. In this review, we explore the roles of inflammatory cytokines, inflammasomes and immune cells in the course of gout development and the research status of therapeutic drugs used for inflammation to provide insights into future targeted therapy for gouty inflammation and the direction of gout pathogenesis research.

Uric acid en route to gout

Gout and hyperuricemia (HU) have generated immense attention due to increased prevalence. Gout is a multifactorial metabolic and inflammatory disease that occurs when increased uric acid (UA) induce HU resulting in monosodium urate (MSU) crystal deposition in joints. However, gout pathogenesis does not always involve these events and HU does not always cause a gout flare. Treatment with UA-lowering therapeutics may not prevent or reduce the incidence of gout flare or gout-associated comorbidities. UA exhibits both pro- and anti-inflammation functions in gout pathogenesis. HU and gout share mechanistic and metabolic connections at a systematic level, as shown by studies on associated comorbidities. Recent studies on the interplay between UA, HU, MSU and gout as well as the development of HU and gout in association with metabolic syndromes, non-alcoholic fatty liver disease (NAFLD), and cardiovascular, renal and cerebrovascular diseases are discussed. This review examines current and potential therapeutic regimens and illuminates the journey from disrupted UA to gout.

Role of pyroptosis in the pathogenesis and treatment of diseases

Programmed cell death (PCD) is regarded as a pathological form of cell death with an intracellular program mediated, which plays a pivotal role in maintaining homeostasis and embryonic development. Pyroptosis is a new paradigm of PCD, which has received increasing attention due to its close association with immunity and disease. Pyroptosis is a form of inflammatory cell death mediated by gasdermin that promotes the release of proinflammatory cytokines and contents induced by inflammasome activation. Recently, increasing evidence in studies shows that pyroptosis has a crucial role in inflammatory conditions like cardiovascular diseases (CVDs), cancer, neurological diseases (NDs), and metabolic diseases (MDs), suggesting that targeting cell death is a potential intervention for the treatment of these inflammatory diseases. Based on this, the review aims to identify the molecular mechanisms and signaling pathways related to pyroptosis activation and summarizes the current insights into the complicated relationship between pyroptosis and multiple human inflammatory diseases (CVDs, cancer, NDs, and MDs). We also discuss a promising novel strategy and method for treating these inflammatory diseases by targeting pyroptosis and focus on the pyroptosis pathway application in clinics.

Macrophage pyroptosis promotes synovial fibrosis through the HMGB1/TGF- β1 axis: an in vivo and in vitro study

Macrophages and fibroblasts are the main effector cells in synovial tissue in the knee joint. Our previous studies showed that there was synovial macrophage pyroptosis in knee osteoarthritis (KOA) and that inhibiting this pyroptosis could alleviate synovial fibrosis. In the present study, we aimed to elucidate the mechanism by which macrophage pyroptosis affects synovial fibrosis. We established an LPS/ATP-induced model in macrophages that mimicked the inflammatory environment of KOA and induced macrophage pyroptosis. The TGF-β1, SMAD3, and P-SMAD3, and the synovial fibrosis markers (Collagen I, TIMP1, Vimentin, and TGF-β1) were significantly decreased after fibroblasts were cultured with RAGE inhibitors and SMAD3 inhibitors. Moreover, ELISA and immunofluorescence analysis showed that macrophage pyroptosis induced the release of IL-1β, IL-18, and HMGB1 and caused the translocation of HMGB1 from the fibroblast nucleus to the cell membrane, where it could bind with RAGE. Subsequently, in the synovial tissue of KOA model rats, we observed that inhibiting HMGB1, RAGE, and SMAD3 could alleviate the expression of synovial fibrosis markers (Collagen I, TIMP1, Vimentin, and TGF-β1) at both the mRNA and protein levels. Besides, HE and Sirius Red staining were used to observe the transverse diameter of the right knee. In conclusion, macrophage pyroptosis induced IL-1β, IL-18, and HMGB1, which could be caused HMGB1 to translocate from the fibroblast nucleus and bind with RAGE, activating the TGF-β1/SMAD3 signaling pathway and affecting synovial fibrosis.

A review on gout: Looking back and looking ahead

Gout is a metabolic disease caused by the deposition of monosodium urate (MSU) crystals inside joints, which leads to inflammation and tissue damage. Increased concentration of serum urate is an essential step in the development of gout. Serum urate is regulated by urate transporters in the kidney and intestine, especially GLUT9 (SLC2A9), URAT1 (SLC22A12) and ABCG. Activation of NLRP3 inflammasome bodies and subsequent release of IL-1β by monosodium urate crystals induce the crescendo of acute gouty arthritis, while neutrophil extracellular traps (NETs) are considered to drive the self-resolving of gout within a few days. If untreated, acute gout may eventually develop into chronic tophaceous gout characterized by tophi, chronic gouty synovitis, and structural joint damage, leading the crushing burden of treatment. Although the research on the pathological mechanism of gout has been gradually deepened in recent years, many clinical manifestations of gout are still unable to be fully elucidated. Here, we reviewed the molecular pathological mechanism behind various clinical manifestations of gout, with a view to making contributions to further understanding and treatment.

Role of NLRP3 in the pathogenesis and treatment of gout arthritis

Gout arthritis (GA) is a common and curable type of inflammatory arthritis that has been attributed to a combination of genetic, environmental and metabolic factors. Chronic deposition of monosodium urate (MSU) crystals in articular and periarticular spaces as well as subsequent activation of innate immune system in the condition of persistent hyperuricemia are the core mechanisms of GA. As is well known, drugs for GA therapy primarily consists of rapidly acting anti-inflammatory agents and life-long uric acid lowering agents, and their therapeutic outcomes are far from satisfactory. Although MSU crystals in articular cartilage detected by arthrosonography or in synovial fluid found by polarization microscopy are conclusive proofs for GA, the exact molecular mechanism of NLRP3 inflammasome activation in the course of GA still remains mysterious, severely restricting the early diagnosis and therapy of GA. On the one hand, the activation of Nod-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome requires nuclear factor kappa B (NF-κB)-dependent transcriptional enhancement of NLRP3, precursor (pro)-caspase-1 and pro-IL-1β, as well as the assembly of NLRP3 inflammasome complex and sustained release of inflammatory mediators and cytokines such as IL-1β, IL-18 and caspase-1. On the other hand, NLRP3 inflammasome activated by MSU crystals is particularly relevant to the initiation and progression of GA, and thus may represent a prospective diagnostic biomarker and therapeutic target. As a result, pharmacological inhibition of the assembly and activation of NLRP3 inflammasome may also be a promising avenue for GA therapy. Herein, we first introduced the functional role of NLRP3 inflammasome activation and relevant biological mechanisms in GA based on currently available evidence. Then, we systematically reviewed therapeutic strategies for targeting NLRP3 by potentially effective agents such as natural products, novel compounds and noncoding RNAs (ncRNAs) in the treatment of MSU-induced GA mouse models. In conclusion, our present review may have significant implications for the pathogenesis, diagnosis and therapy of GA.

A mechanically tough and ultra-swellable microneedle for acute gout arthritis

Acute gout arthritis (AGA) remains the fundamental research focus in the entire medical field. Hydrogel microneedles (HMNs) loaded with therapeutic molecules such as colchicine (Col) have been developed as a new tool for the management of AGA in a minimally invasive manner. However, the incompatible mechanical and swelling properties of HMNs limited the diffusion of the drug from the HMN system, which remains a challenge for practical use. Here, a mechanically tough (11.53 N per needle) and super-swelling (2708%) hydrogel microneedle (HMNs) composed of a uniform network structure was developed using a UV-responsive crosslinker through in situ photopolymerization for percutaneous delivery of Col. Such HMNs and Col loaded HMNs (Col-HMNs) present excellent biocompatibility. Moreover, Col-HMNs present considerable anti-inflammatory effects in vivo through down-regulated inflammatory responses such as related cytokines IL-1β, IL-6, and TNF-α. These results demonstrated that the mechanically tough and super-swelling HMNs could be a promising tool for effective Col delivery to relieve AGA.

Piezo2 channels expressed by colon-innervating TRPV1-lineage neurons mediate visceral mechanical hypersensitivity

Inflammatory and functional gastrointestinal disorders such as irritable bowel syndrome (IBS) and obstructive bowel disorder (OBD) underlie the most prevalent forms of visceral pain. Although visceral pain can be generally provoked by mechanical distension/stretch, the mechanisms that underlie visceral mechanosensitivity in colon-innervating visceral afferents remain elusive. Here, we show that virally mediated ablation of colon-innervating TRPV1-expressing nociceptors markedly reduces colorectal distention (CRD)-evoked visceromotor response (VMR) in mice. Selective ablation of the stretch-activated Piezo2 channels from TRPV1 lineage neurons substantially reduces mechanically evoked visceral afferent action potential firing and CRD-induced VMR under physiological conditions, as well as in mouse models of zymosan-induced IBS and partial colon obstruction (PCO). Collectively, our results demonstrate that mechanosensitive Piezo2 channels expressed by TRPV1-lineage nociceptors powerfully contribute to visceral mechanosensitivity and nociception under physiological conditions and visceral hypersensitivity under pathological conditions in mice, uncovering potential therapeutic targets for the treatment of visceral pain.

TRPV4 is not the molecular sensor for bacterial lipopolysaccharides-induced calcium signaling

Lipopolysaccharides (LPS) is one of the most potent pathogen-associated signals for the immune system of vertebrates. In addition to the canonical pathway of LPS detection mediated by toll-like receptor 4 (TLR4) signaling pathway, TRP channel-mediated pathways endow sensory neurons and epithelial cells with the ability to detect and react to bacterial endotoxins. Previous work revealed that LPS triggers TRPV4-dependent calcium influx in urothelial cells (UCs) and mouse tracheobronchial epithelial cells (mTEC). In marked contrast, here we show that most subtypes of LPS could not directly activate TRPV4 channel. Although LPS from Salmonella enterica serotype Minnesota evoked a [Ca²⁺]_i response in freshly isolated human bronchial epithelial cells (ECs), freshly isolated mouse ear skin single-cell suspensions, or HEK293T cells transiently transfected with mTRPV4, this activation occurred in a TRPV4-independent manner. Additionally, LPS from either E. coli strains or Salmonella enterica serotype Minnesota did not evoke significant difference in inflammation and pain hyperalgesia between wild type and TRPV4 deficient mice. In summary, our results demonstrate that in vitro and in vivo effects induced by LPS are independent of TRPV4, thus providing a clarity to the questioned role of LPS in TRPV4 activation.

Chronic kidney disease and NLRP3 inflammasome: Pathogenesis, development and targeted therapeutic strategies

Chronic kidney disease (CKD) is a global health concern and public health priority. The condition often involves inflammation due to the accumulation of toxins and the reduced clearance of inflammatory cytokines, leading to gradual loss of kidney function. Because of the tremendous burden of CKD, finding effective treatment strategies against inflammation is crucial. Substantial evidence suggests an association between kidney disease and the inflammasome. As a well-known multiprotein signaling complex, the NLR family pyrin domain containing 3 (NLRP3) inflammasome plays an important role in inducing renal inflammation and fibrosis. Small molecule inhibitors targeting the NLRP3 inflammasome are potential agents for the treatment of CKD.The NLRP3 inflammasome activation amplifies the inflammation response, promoting pyroptotic cell death. Thus, it may contribute to the onset and progression of CKD, but the mechanism behind inflammasome activation in CKD remains obscure.In this review, we summarized recent findings on the role of the NLRP3 inflammasome in CKD and new strategies targeting the NLRP3 inflammasome.

Lipoxin A4 attenuates MSU-crystal-induced NLRP3 inflammasome activation through suppressing Nrf2 thereby increasing TXNRD2

Gout is a common inflammatory disease. The activation of NLRP3 inflammasome induced by monosodium urate (MSU) crystals has a critical role in gout, and its prevention is beneficial for patients. Lipoxin A4 (LXA4) is an endogenous lipoxygenase-derived eicosanoid mediator with powerful anti-inflammatory properties. However, whether LXA4 can suppress NLRP3 inflammasome activation induced by MSU crystals remains unclear. This study aimed to investigate the protective effect of LXA4 on MSU-crystal-induced NLRP3 inflammasome activation and its underlying molecular mechanisms. We found that LXA4 inhibited MSU-crystal-induced NLRP3 inflammasome activation, interleukin (IL)-1β maturation, and pyroptosis. More specifically, LXA4 suppressed the assembly of the NLRP3 inflammasome, including oligomerization and speck formation of ASC, and ASC-NLRP3 interaction. Furthermore, LXA4 suppressed oxidative stress, the upstream events for NLRP3 inflammasome activation, as evidenced by the fact that LXA4 eliminated total reactive oxygen species (ROS) generation and alleviated nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activation and mitochondrial dysfunction. However, LXA4 also depressed the Nrf2 activation, a critical molecule in the antioxidant pathway, and then exerted an inhibitory impact on Klf9 expression and promotional impact on TXNRD2 expression, two molecules located downstream of Nrf2 in sequence. Knockdown of TXNRD2 reversed the LXA4-induced depression of ROS and NLRP3 inflammasome. Moreover, LXA4 alleviated joint inflammation and decreased the production of cleaved caspase-1 and matured IL-1β in gouty arthritis rats. Taken together, our findings demonstrate that LXA4 can attenuate MSU-crystal-induced NLRP3 inflammasome activation, probably through suppressing Nrf2 activation to increase TXNRD2 expression. The present study highlights the potential of LXA4 as an attractive new gout treatment candidate.

Recent Insights Into the Role of Macrophages in Acute Gout

Gout is a common type of inflammatory arthritis characterized by the presence of monosodium urate crystals (MSU) in the joints. Macrophages are believed to be involved in gout flares. It has long been recognized that resident macrophage and monocyte derived macrophages are distinct subsets and there have been attempts to investigate their roles in acute gout, respectively. Previous studies revealed that resident macrophages initiate and drive the inflammation, while monocyte derived macrophages differentiated into M1-like macrophages in response to MSU crystals. With the advancement of technologies, subpopulations of synovial resident macrophages have been defined with the characteristics more accurately described. Resident macrophages in the synovial lining layer showed an anti-inflammatory effect in rheumatoid arthritis, but specific Trpv4 depletion of them reduced MSU crystals induced murine arthritis. CD14+ monocytes in the synovial fluid from patients with gout exhibit phenotypes of anti-inflammatory as well as pro-inflammatory characteristics. Here, we review the main aspects of macrophages in the initiation and resolution of acute gout and try to clarify the specific role of each subpopulation. Building a reliable diagram of the effect of monocytes and macrophages during MSU crystals induced arthritis will bring us closer to targeting macrophages for improving the management of gout.

Inflammatory Response to Regulated Cell Death in Gout and Its Functional Implications

Gout, a chronic inflammatory arthritis disease, is characterized by hyperuricemia and caused by interactions between genetic, epigenetic, and metabolic factors. Acute gout symptoms are triggered by the inflammatory response to monosodium urate crystals, which is mediated by the innate immune system and immune cells (e.g., macrophages and neutrophils), the NACHT, LRR, and PYD domains-containing protein 3 (NLRP3) inflammasome activation, and pro-inflammatory cytokine (e.g., IL-1β) release. Recent studies have indicated that the multiple programmed cell death pathways involved in the inflammatory response include pyroptosis, NETosis, necroptosis, and apoptosis, which initiate inflammatory reactions. In this review, we explore the correlation and interactions among these factors and their roles in the pathogenesis of gout to provide future research directions and possibilities for identifying potential novel therapeutic targets and enhancing our understanding of gout pathogenesis.

The Emerging Pro-Algesic Profile of Transient Receptor Potential Vanilloid Type 4

Transient receptor potential vanilloid type 4 (TRPV4) channels are Ca²⁺-permeable non-selective cation channels which mediate a wide range of physiological functions and are activated and modulated by a diverse array of stimuli. One of this ion channel's least discussed functions is in relation to the generation and maintenance of certain pain sensations. However, in the two decades which have elapsed since the identification of this ion channel, considerable data has emerged concerning its function in mediating pain sensations. TRPV4 is a mediator of mechanical hyperalgesia in the various contexts in which a mechanical stimulus, comprising trauma (at the macro-level) or discrete extracellular pressure or stress (at the micro-level), results in pain. TRPV4 is also recognised as constituting an essential component in mediating inflammatory pain. It also plays a role in relation to many forms of neuropathic-type pain, where it functions in mediating mechanical allodynia and hyperalgesia.Here, we review the role of TRPV4 in mediating pain sensations.

Targeted Therapy for Primary Sjögren's Syndrome: Where are We Now?

Primary Sjögren's syndrome (pSS) is an autoimmune exocrinopathy characterized by dryness symptoms. This review briefly describes recent advances in the targeted therapies for pSS. Biologics evaluated for pSS treatment mainly include B cell-depleting agents, inhibitors of B cell activation, and agents that target co-signaling molecules or proinflammatory cytokines. Small molecule inhibitors that target signaling pathways have also been evaluated. However, current evidence for the efficacy of targeted therapies in pSS is still sparse. Although ianalumab (an anti-B cell-activating factor [BAFF]-receptor antibody) and iscalimab (an anti-CD40 antibody) are promising biologics for pSS, their efficacy still needs to be evaluated in larger clinical trials. For other biologics, clinical trials have found no differences versus placebo in the change from baseline in European League Against Rheumatism Sjögren's Syndrome Disease Activity Index (ESSDAI) score and fatigue score. Possible causes of the disappointing outcomes mainly include the inefficacy of those evaluated biologics in treating pSS, the high heterogeneous nature of pSS, irreversible exocrine glandular failure at advanced disease stages, inappropriate recruitment strategy in clinical trials, and outcome measures. Early diagnosis and glandular function-centered outcome measures may help to improve the current situation in the systemic therapy of pSS.

A systematic review of clinical and preclinical evidences for Janus kinase inhibitors in large vessel vasculitis

Corticosteroid-sparing disease-modifying anti-rheumatic drugs are an area of active exploration in large vessel vasculitis (LVV), i.e., Takayasu arteritis (TAK) and Giant Cell Arteritis (GCA). The role of Janus kinase (JAK) inhibitors has been recently identified in different inflammatory rheumatic diseases. We conducted a systematic review of the use of JAK inhibitors in LVV across MEDLINE, Scopus, Web of Science, EMBASE, PubMed Central, Cochrane database of controlled trials, clinicaltrials.gov, and major recent international conferences. We identified four cohort studies and ten case reports. The JAK inhibitors used in these studies were tofacitinib, baricitinib, and ruxolitinib. A cohort study in TAK compared 27 patients treated with tofacitinib with 26 others treated with methotrexate, with better clinical outcomes with tofacitinib but similar angiographic stabilization, relapses, corticosteroid-sparing effect, and adverse events in both groups. Most of the other studies favored clinical responses with JAK inhibitors in LVV but with a paucity of data on other outcomes. Most of the included studies were of moderate quality. Evidence from pre-clinical models of LVV as well as limited in vivo data in patients with TAK appears to suggest that JAK inhibition reduces adventitial fibrosis, intimal proliferation, and inflammatory T lymphocyte infiltration in the media as well as reduces resident memory T cells in the vascular wall (which are otherwise resistant to corticosteroids). Ongoing clinical trials of tofacitinib, baricitinib, and upadacitinib in LVV shall help to further clarify the potential promise of JAK inhibitors for LVV (PROSPERO registration number CRD42021273359). KEY POINTS : •Tofacitinib appeared to associate with better clinical outcomes than methotrexate in TAK. •JAKinibs reduce adventitial fibrosis, intimal proliferation, and inflammatory vascular infiltrate in pre-clinical models of LVV. •Tofacitinib downregulates resident memory vascular T lymphocytes in pre-clinical models of LVV.