Saxagliptin suppresses degradation of type II collagen and aggrecan in primary human chondrocytes: a therapeutic implication in osteoarthritis

Targeting FAP-positive chondrocytes in osteoarthritis: a novel lipid nanoparticle siRNA approach to mitigate cartilage degeneration

BACKGROUND

Osteoarthritis (OA) is a common joint disease that leads to chronic pain and functional limitations. Recent research has revealed soluble fibroblast activation protein (FAP) secreted from OA synovium could degrade type II collagen (Col2) in cartilage to promote the progression of OA. This study aimed to reveal the role of FAP from chondrocytes in OA and develop a novel lipid nanoparticle (LNP)-FAP siRNA delivery system for OA treatment.

METHODS

The expression of FAP in the cartilage of knee OA patients was investigated using [68 Ga]Ga-FAPI-04 PET in vivo and immunofluorescence, western blotting, and RT-qPCR in vitro. Cell senescence was determined by senescence-associated β-galactosidase (SA-β-Gal) assay after FAP overexpressing or knockdown in chondrocytes. An OA model with chondrocyte-specific FAP knockout mice was applied to investigate the role of FAP in chondrocyte senescence and OA development. The therapeutic effects of lipid nanoparticle (LNP) @FAP siRNA on cartilage degeneration were evaluated in the rat OA model.

RESULTS

Our study found that higher [68 Ga]Ga-FAPI-04 uptake was detected in knee OA patients by PET/CT scan. FAP mRNA and protein levels were highly expressed in OA-damaged cartilage. Moreover, we found that overexpression of FAP promotes chondrocyte senescence, and the genetic knockout of FAP in chondrocytes alleviates OA. Knockdown FAP by siRNA could alleviate chondrocyte senescence and suppress the NF-κB pathway to reduce the senescence-associated secretory phenotype (SASP). In the rat model of OA, intraarticular injection of LNP@FAP siRNA can reduce senescent cells and ameliorate cartilage destruction.

CONCLUSION

FAP-positive chondrocytes play a significant role in the pathogenesis of OA. Targeting these cells selectively has the potential to mitigate the progression of the disease. Our study provides valuable insights into the intraarticular injection of LNP@FAP siRNA as a promising strategy for the treatment of OA.

Efficacy, Safety, and Tolerability of a Very Low-Calorie Ketogenic Diet in Women with Obesity and Symptomatic Knee Osteoarthritis: A Pilot Interventional Study

BACKGROUND/OBJECTIVES

Obesity is a major risk factor for knee osteoarthritis (OA), and weight loss is crucial for its management. This pilot study explores the effects of a Very Low-Calorie Ketogenic Diet (VLCKD) in women with obesity and symptomatic knee OA.

METHODS

Women with symptomatic knee OA and obesity, defined as a body mass index (BMI) ≥ 30 kg/m2, were eligible for the VLCKD protocol. The intervention included a ketogenic phase from baseline (T0) to the 8th week (T8), followed by a progressive reintroduction of carbohydrates over the next 12 weeks, ending at the 20th week (T20). Body mass index (BMI), the Western Ontario and McMaster Universities (WOMAC) Osteoarthritis Index, the EuroQol 5D (EQ-5D), and the 36-item Short Form Health Survey (SF-36) were assessed at all time points. Generalized estimating equations were used to analyze the association between BMI and patient-reported outcomes across the study period.

RESULTS

Twenty participants started the study, but four discontinued the intervention, with two of these being due to adverse effects. The mean age of the 16 patients who completed the 20-week program was 57.3 ± 5.5 years, and their mean BMI was 40.0 ± 4.8 kg/m2. The mean BMI significantly decreased to 37.5 ± 4.5 at T4, 36.3 ± 4.6 at T8, and 34.8 ± 4.8 at T20 (all p < 0.001 compared to baseline). The total WOMAC score improved from a mean of 43.6 ± 16.9 at T0 to 30.2 ± 12.8 at T4 (p = 0.005) and further to 24.7 ± 10.6 at T8 (p = 0.001) and to 24.8 ± 15.9 at T20 (p = 0.005). The reduction in BMI was significantly correlated with the improvements in WOMAC, EQ-5D, and SF-36 over time. No major adverse effects were observed.

CONCLUSIONS

A 20-week VLCKD in women with obesity and knee OA significantly reduced their weight and improved their outcomes, warranting further research. This trial is registered with number NCT05848544 on ClinicalTrials.gov.

Liensinine inhibits IL-1β-stimulated inflammatory response in chondrocytes and attenuates papain-induced osteoarthritis in rats

Osteoarthritis (OA) is a joint disease caused by inflammation of cartilage and synovial tissue. Suppressing the process of inflammatory reaction and the generation of oxidative stress is an effective strategy to alleviate the progression of OA. Liensinine is one of the main components of lotus seeds, which has anti-hypertensive and anti-arrhythmia activities. In this study, we aimed to determine the anti-inflammatory effect of liensinine in an OA. Here, we found that liensinine significantly inhibited the inflammatory response of SW1353 cells and primary chondrocytes by inhibiting the release of inflammatory cytokines and oxidative stress. Moreover, we showed that liensinine was able to inhibit the activation of the NF-κB signaling pathway in IL-1β-induced SW1353 cells. Lastly, we found that liensinine significantly ameliorated cartilage damage and inflammatory response in papain-induced rats. Our study demonstrated a significant protective effect of liensinine against OA, which might be by inhibiting the activation of the NF-κB signaling pathway, and provide a new insight for the treatment of OA using liensinine.

Repurposing drugs for the treatment of osteoarthritis

OBJECTIVE

Currently, no disease-modifying therapies for osteoarthritis (OA) exist, and attempts to identify novel cellular targets have been challenging. Risk factors for OA include advanced age, obesity, and metabolic syndrome. This creates an attractive opportunity to repurpose existing drugs that are used to treat comorbidities commonly encountered in patients with OA, if those drugs possess OA disease modifying properties.

METHODS

This narrative review incorporates findings from knee or hand OA randomized clinical trials, post-hoc clinical trial analyses, prospective cohort studies, and observational data.

RESULTS

Drugs used for the treatment of rheumatoid arthritis (methotrexate; TNFa, IL-1, and IL-6 pathway inhibitors; hydroxychloroquine), atopic/allergic disease (anti-histamines), osteoporosis (bisphosphonates and vitamin D), type 2 diabetes (metformin and GLP-1 agonists), and cardiovascular disease (atorvastatin, fish oil, and beta blockers) were reviewed for their potential benefit in OA. This review outlines the successful attributes of repurposed drugs, the challenges in repurposing drugs, and strategies for future clinical trials to support OA drug repurposing. Potential drug candidates for OA may be identified through the use of existing datasets and via collaborations with researchers in other fields to include OA endpoints in future clinical trials.

CONCLUSION

Given the association of OA with several commonly treated comorbidities, drug repurposing is an appealing approach that could provide a favorable benefit-to-risk ratio for chronic OA treatment.

Surface functionalization of exosomes for chondrocyte-targeted siRNA delivery and cartilage regeneration

Osteoarthritis (OA) is the most prevalent degenerative cartilage disease, but no effective treatment is currently available to ameliorate the dysregulation of cartilage catabolism. Cartilage degeneration is closely related to the change in the physiology of chondrocytes: for example, chondrocytes of the OA patients overexpress matrix metallopeptidase 13 (MMP13), a.k.a. collagenase 3, which damages the extracellular matrix (ECM) of the cartilage and deteriorate the disease progression. Inhibiting MMP13 has shown to be beneficial for OA treatments, but delivering therapeutics to the chondrocytes embedded in the dense cartilage is a challenge. Here, we engineered the exosome surface with the cartilage affinity peptide (CAP) through lipid insertion to give chondrocyte-targeting exosomes, CAP-Exo, which was then loaded with siRNA against MMP13 (siMMP13) in the interior to give CAP-Exo/siMMP13. Intra-articular administration of CAP-Exo/siMMP13 reduced the MMP13 level and increased collagen COL2A1 and proteoglycan in cartilage in a rat model of anterior cruciate ligament transection (ACLT)-induced OA. Proteomic analysis showed that CAP-Exo/siMMP13 treatment restored the altered protein levels in the IL-1β-treated chondrocytes. Taken together, a facile exosome engineering method enabled targeted delivery of siRNA to chondrocytes and chondrocyte-specific silencing of MMP13 to attenuate cartilage degeneration.

Undenatured type II collagen and its role in improving osteoarthritis

Osteoarthritis (OA) is a degenerative joint disease, affecting 32.5 million US adults or 242 million people worldwide. There is no cure for OA. Many animal and clinical trials showed that oral administration of undenatured type II collagen could significantly reduce the incidence of OA or alleviate the symptoms of articular cartilage. Type II collagen is an important component of cartilage matrix. This article reviewed research progress of undenatured type II collagen including its methods of extraction and preparation, structure and characterization, solubility, thermal stability, gastrointestinal digestive stability, its role in improving OA, and the mechanism of its action in improving OA. Type II collagen has been extensively explored for its potential in improving arthritis. Methods of extraction of type II collagen are inefficient and tedious. The method of limited enzymatic hydrolysis is mainly used to prepare soluble undenatured type II collagen (SC II). The solubility, thermal and gastrointestinal digestive stability of SC II are affected by the sources of raw material, pH, salt ions, and temperature. Oral administration of undenatured type II collagen improves OA, whereas its activity is affected by the sources, degree of denaturalization, intervention methods and doses. However, the influence of the structure of undenatured type II collagen on its activity and the mechanism are unclear. The findings in this review support that undenatured type II collagen can be used in the intervention or auxiliary intervention of patients with OA.

Senescence in osteoarthritis: from mechanism to potential treatment

Osteoarthritis (OA) is an age-related cartilage degenerative disease, and chondrocyte senescence has been extensively studied in recent years. Increased numbers of senescent chondrocytes are found in OA cartilage. Selective clearance of senescent chondrocytes in a post-traumatic osteoarthritis (PTOA) mouse model ameliorated OA development, while intraarticular injection of senescent cells induced mouse OA. However, the means and extent to which senescence affects OA remain unclear. Here, we review the latent mechanism of senescence in OA and propose potential therapeutic methods to target OA-related senescence, with an emphasis on immunotherapies. Natural killer (NK) cells participate in the elimination of senescent cells in multiple organs. A relatively comprehensive discussion is presented in that section. Risk factors for OA are ageing, obesity, metabolic disorders and mechanical overload. Determining the relationship between known risk factors and senescence will help elucidate OA pathogenesis and identify optimal treatments.

Sappanone A Alleviated IL-1β-Induced Inflammation in OA Chondrocytes through Modulating the NF-κB and Nrf2/HO-1 Pathways

Objective

This study was to examine the anti-inflammatory effect of sappanone A on interleukin- (IL-) 1β-stimulated osteoarthritis (OA) chondrocytes.

Methods

Chondrocytes were pretreated with sappanone A for 2 h before subsequent IL-1β stimulation. The mRNA expression levels of iNOs, COX-2, aggrecan, and collagen-II were measured with qRT-PCR. The levels of TNF-α, IL-6, IL-8, MMP-3, and MMP-13 were determined by ELISA. The protein levels of iNOs, COX-2, ADAMTS-4, ADAMTS-5, aggrecan, collagen-II, p-p65, p65, IκBα, Nrf2, and HO-1 were assessed by Western blot.

Results

Sappanone A inhibited the IL-1β-stimulated production of NO, PGE2, iNOS, COX-2, TNF-α, IL-6, and IL-8 in OA chondrocytes. In addition, sappanone A suppressed the expression of MMP-3, MMP-13, ADAMTS-4, and ADAMTS-5 in IL-1β-stimulated OA chondrocytes. The degradation of ECM components was reversed by sappanone A. Sappanone A prevented NF-κB activation while enhanced Nrf2/HO-1 activation in IL-1β-treated chondrocytes.

Conclusion

Sappanone A may be a potent therapeutic agent for OA.

The Role Played by Ferroptosis in Osteoarthritis: Evidence Based on Iron Dyshomeostasis and Lipid Peroxidation

Ferroptosis, a recently discovered regulated cell death modality, is characterised by iron-dependent accumulation of lipid hydroperoxides, which can reach lethal levels but can be specifically reversed by ferroptosis inhibitors. Osteoarthritis (OA), the most common degenerative joint disease, is characterised by a complex pathogenesis involving mechanical overload, increased inflammatory mediator levels, metabolic alterations, and cell senescence and death. Since iron accumulation and oxidative stress are the universal pathological features of OA, the role played by ferroptosis in OA has been extensively explored. Increasing evidence has shown that iron dyshomeostasis and lipid peroxidation are closely associated with OA pathogenesis. Therefore, in this review, we summarize recent evidence by focusing on ferroptotic mechanisms and the role played by ferroptosis in OA pathogenesis from the perspectives of clinical findings, animal models, and cell research. By summarizing recent research advances that characterize the relationship between ferroptosis and OA, we highlight avenues for further research and potential therapeutic targets.

The effects of metformin in the treatment of osteoarthritis: Current perspectives

Osteoarthritis is a chronic and irreversible disease of the locomotor system which is closely associated with advancing age. Pain and limited mobility frequently affect the quality of life in middle-aged and older adults. With a global population of more than 350 million, osteoarthritis is becoming a health threat alongside cancer and cardiovascular disease. It is challenging to find effective treatments to promote cartilage repair and slow down disease progression. Metformin is the first-line drug for patients with type 2 diabetes, and current perspectives suggest that it cannot only lower glucose but also has anti-inflammatory and anti-aging properties. Experimental studies applying metformin for the treatment of osteoarthritis have received much attention in recent years. In our review, we first presented the history of metformin and the current status of osteoarthritis, followed by a brief review of the mechanism that metformin acts, involving AMPK-dependent and non-dependent pathways. Moreover, we concluded that metformin may be beneficial in the treatment of osteoarthritis by inhibiting inflammation, modulating autophagy, antagonizing oxidative stress, and reducing pain levels. Finally, we analyzed the relevant evidence from animal and human studies. The potential of metformin for the treatment of osteoarthritis deserves to be further explored.

Ketogenic diet ameliorates inflammation by inhibiting the NLRP3 inflammasome in osteoarthritis

BACKGROUND

The nucleotide-binding domain, leucine-rich repeat, and pyrin domain-containing protein 3 (NLRP3) inflammasome has been reported to be involved in the pathological process of osteoarthritis (OA) inflammation. Here, we investigated the ketogenic diet (KD), which has been previously demonstrated to inhibit NLRP3 inflammasome activation, to elucidate its protective mechanism against OA in rats.

METHODS

Anterior cruciate ligament transaction (ACLT) together with partial medial meniscectomy was used to create a rat knee joint OA model. After treatment with KD or standard diet (SD) for 8 weeks, the knee specimens were obtained for testing.

RESULTS

The KD significantly increased the content of β-hydroxybutyrate (βOHB) in rats. Compared to the SD group, the KD significantly reduced the damage caused by OA in the articular cartilage and subchondral bone. The NLRP3 inflammasome and inflammatory cytokines interleukin-1 β (IL-1β) and IL-18 were significantly increased in the SD group compared with the sham group, while their expression was significantly decreased in rats treated with the KD. In addition, MMP13 was significantly decreased in the KD group compared to that in the SD group, while COL2 was significantly increased.

CONCLUSIONS

KD can protect the articular cartilage and subchondral bone in a rat OA model by inhibiting NLRP3 inflammasome activation and reducing the OA inflammatory response.

Emerging Role of Dipeptidyl Peptidase-4 in Autoimmune Disease

Dipeptidyl-peptidase IV (DPP4), originally identified as an aminopeptidase in 1960s, is an ubiquitously expressed protease presented as either a membrane-bound or soluble form. DPP4 cleaves dipeptide off from the N-terminal of its substrates, altering the bioactivity of its substrates. Subsequent studies reveal that DPP4 is also involved in various cellular processes by directly binding to a number of ligands, including adenosine deaminase, CD45, fibronectin, plasminogen, and caveolin-1. In recent years, many novel functions of DPP4, such as promoting fibrosis and mediating virus entry, have been discovered. Due to its implication in fibrotic response and immunoregulation, increasing studies are focusing on the potential role of DPP4 in inflammatory disorders. As a moonlighting protein, DPP4 possesses multiple functions in different types of cells, including both enzymatic and non-enzymatic functions. However, most of the review articles on the role of DPP4 in autoimmune disease were focused on the association between DPP4 enzymatic inhibitors and the risk of autoimmune disease. An updated comprehensive summary of DPP4’s immunoregulatory actions including both enzymatic dependent and independent functions is needed. In this article, we will review the recent advances of DPP4 in immune regulation and autoimmune rheumatic disease.

Hsa_circ_0032131 knockdown inhibits osteoarthritis progression via the miR-502-5p/PRDX3 axis

Osteoarthritis (OA) is a chronic disease characterized by progressive loss of cartilage and failure of the diarthrodial joint. Circular RNAs (circRNAs) are known to participate in the pathogenesis of multiple diseases, including OA. We investigated the functions of hsa_circ_0032131, a circRNA upregulated in OA, using CHON-001 cells and an in vivo OA rat model. CHON-001 cells were treated with interleukin (IL)-1β to mimic OA in vitro. IL-1β-induced inhibition of CHON-001 growth was reversed by silencing hsa_circ_0032131. In addition, hsa_circ_0032131 knockdown reversed IL-1β-induced activation of Trx1, Cyclin D and PRDX3, whereas overexpression of PRDX3, a direct target of miR-502-5p, reversed this effect. Hsa_circ_0032131 served as a competing endogenous RNA for miR-502-5p. Moreover, knockdown of hsa_circ_0032131 attenuated OA symptoms in vivo by inactivating the STAT3 signaling pathway. Thus, silencing of hsa_circ_0032131 inhibited the progression of OA by inactivating the miR-502-5p/PRDX3/Trx1/STAT3 axis, which highlights its potential as a therapeutic target for OA.

Insulin Signaling in Arthritis

Inflammatory arthritis is burdened by an increased risk of metabolic disorders. Cytokines and other mediators in inflammatory diseases lead to insulin resistance, diabetes and hyperlipidemia. Accumulating evidence in the field of immunometabolism suggests that the cause-effect relationship between arthritis and metabolic abnormalities might be bidirectional. Indeed, the immune response can be modulated by various factors such as environmental agents, bacterial products and hormones. Insulin is produced by pancreatic cells and regulates glucose, fat metabolism and cell growth. The action of insulin is mediated through the insulin receptor (IR), localized on the cellular membrane of hepatocytes, myocytes and adipocytes but also on the surface of T cells, macrophages, and dendritic cells. In murine models, the absence of IR in T-cells coincided with reduced cytokine production, proliferation, and migration. In macrophages, defective insulin signaling resulted in enhanced glycolysis affecting the responses to pathogens. In this review, we focalize on the bidirectional cause-effect relationship between impaired insulin signaling and arthritis analyzing how insulin signaling may be involved in the aberrant immune response implicated in arthritis and how inflammatory mediators affect insulin signaling. Finally, the effect of glucose-lowering agents on arthritis was summarized.

Modified Simiaowan prevents articular cartilage injury in experimental gouty arthritis by negative regulation of STAT3 pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Modified Simiaowan (MSW) is a traditional Chinese medicine formula that is composed of six herbs. It has been widely used in the treatment of gouty arthritis.

AIM OF THE STUDY

This study was designed to investigate the effect of MSW on gouty arthritis and explore the possible mechanisms.

MATERIAL AND METHODS

The rat gouty arthritis model was established by intra-articular injection of Monosodium Urate (MSU) crystal, and then treated with MSW for 5 days. The perimeter of the knee joints was measured in a time-dependent manner and serum samples were collected for the detection of TNF-α, IL-1β, and IL-6 protein levels by ELISA. The protein expressions of MMP-3, TIMP-3, STAT3, and p-STAT3 in cartilage tissues and C28/I2 cells were detected by Western blot, and the levels of proteoglycan in primary chondrocytes and cartilage tissues were determined by toluidine blue staining. In addition, AG490 and IL-6 were used in vitro to explore the function of IL-6/STAT3 pathway in the protective effect of MSU.

RESULTS

MSW reduced the joint swelling rate in gouty arthritis model and inhibited MSU induced up-regulation of IL-1β, TNF-α, and IL-6 protein levels in serum and synovial fluid. IL-1β induced an increase in p-STAT3 and MMP-3 protein expression in C28/I2 cells, as well as a decrease in TIMP-3. MSW serum inhibited the protein expression changes induced by IL-1β in vitro. Furthermore, inhibition of STAT3 signaling negated the effect of MSW serum on p-STAT3, MMP-3, and TIMP-3 protein levels in C28/I2 cells. MSW also increased the content of proteoglycan significantly both in vivo and in vitro.

CONCLUSION

Our data indicated that MSW protected rats from MSU-induced experimental gouty arthritis and IL-1β/IL-6/STAT3 pathway played an essential role in the protective effect of MSU against GA.

Advanced glycation end products in musculoskeletal system and disorders

The human population is ageing globally, and the number of old people is increasing yearly. Diabetes is common in the elderly, and the number of diabetic patients is also increasing. Elderly and diabetic patients often have musculoskeletal disorder, which are associated with advanced glycation end products (AGEs). AGEs are heterogeneous molecules derived from non-enzymatic products of the reaction of glucose or other sugar derivatives with proteins or lipids, and many different types of AGEs have been identified. AGEs are a biomarker for ageing and for evaluating disease conditions. Fluorescence, spectroscopy, mass spectrometry, chromatography, and immunological methods are commonly used to measure AGEs, but there is no standardized evaluation method because of the heterogeneity of AGEs. The formation of AGEs is irreversible, and they accumulate in tissue, eventually causing damage. AGE accumulation has been confirmed in neuromusculoskeletal tissues, including bones, cartilage, muscles, tendons, ligaments, and nerves, where they adversely affect biomechanical properties by causing charge changes and forming cross-linkages. AGEs also bind to receptors, such as the receptor for AGEs (RAGE), and induce inflammation by intracellular signal transduction. These mechanisms cause many varied aging and diabetes-related pathological conditions, such as osteoporosis, osteoarthritis, sarcopenia, tendinopathy, and neuropathy. Understanding of AGEs related pathomechanism may lead to develop novel methods for the prevention and therapy of such disorders which affect patients' quality of life. Herein, we critically review the current methodology used for detecting AGEs, and present potential mechanisms by which AGEs cause or exacerbate musculoskeletal disorders.

Evaluation of Long-Time Decoction-Detoxicated Hei-Shun-Pian (Processed Aconitum carmichaeli Debeaux Lateral Root With Peel) for Its Acute Toxicity and Therapeutic Effect on Mono-Iodoacetate Induced Osteoarthritis

Background

As a degenerative joint disease with severe cartilage destruction and pain, osteoarthritis (OA) has no satisfactory therapy to date. In traditional Chinese medicine (TCM), Aconitum carmichaeli Debeaux derived Hei-shun-pian (Hsp) has been developed for joint pain treatment. However, it causes adverse events in OA patients. Long-time decoction has been traditionally applied to reduce the aconite toxicity of Hsp and other aconite herbs, but its detoxifying effect is uncertain.

Methods

Hsp was extracted with dilute decoction times (30, 60, and 120 min) and evaluated by toxicological, chemical, pharmacological assays. Acute toxicity assay and chemical analysis were employed to determine the toxicity and chemoprofile of Hsp extracts, respectively. Since the detoxified Hsp (dHsp) was defined, its therapeutic effect was evaluated by using an OA rat model induced by monosodium iodoacetate. dHsp at 14 g/kg was orally administered for 28 days, and the pain assessments (mechanical withdrawal threshold and thermal withdrawal latency) and histopathological analyses (HE and safranin-O staining) were performed. Real-time PCR (qPCR) was applied to determine the molecular actions of dHsp on cartilage tissue and on chondrocytes. MTT assay was conducted to evaluate the effect of dHsp on the cell viability of chondrocytes. The cellular and molecular assays were also conducted to analyze the functions of chemical components in dHsp.

Results

The chemoprofile result showed that the contents of toxic alkaloids (aconitine, mesaconitine, and hypaconitine) were decreased but that of non-toxic alkaloids (benzoylaconitine, benzoylmesaconitine, and benzoylhypaconitine) were increased with increasing decoction time. Acute toxicity assay showed that only Hsp extract with 120 min decoction was non-toxic within the therapeutic dose range. Thus, it was defined as dHsp for further experiment. In OA experiment, dHsp significantly attenuated joint pain and prevented articular degeneration from MIA attack. qPCR data showed that dHsp restored the abnormal expressions of Col10, Mmp2, Sox5, Adamts4/5/9, and up-regulated Col2 expression in rat cartilage. In vitro, dHsp-containing serum significantly proliferated rat chondrocytes and regulated the gene expressions of Col2, Mmp1, Adamts9, and Aggrecan in a similar way as the in vivo data. Moreover, aconitine, mesaconitine, and hypaconitine exerted cytotoxic effects on chondrocytes, while benzoylaconitine and benzoylhypaconitine except benzoylmesaconitine exhibited similar molecular actions to dHsp, indicating contributions of benzoylaconitine and benzoylhypaconitine to dHsp.

Conclusions

This study defined dHsp and demonstrated dHsp as a potential analgesic and disease modifying agent against OA with molecular actions on the suppression of chondrocyte hypertrophy and extracellular matrix degradation, providing a promising TCM candidate for OA therapy.

Insulin Resistance in Osteoarthritis: Similar Mechanisms to Type 2 Diabetes Mellitus

Osteoarthritis (OA) and type 2 diabetes mellitus (T2D) are two of the most widespread chronic diseases. OA and T2D have common epidemiologic traits, are considered heterogenic multifactorial pathologies that develop through the interaction of genetic and environmental factors, and have common risk factors. In addition, both of these diseases often manifest in a single patient. Despite differences in clinical manifestations, both diseases are characterized by disturbances in cellular metabolism and by an insulin-resistant state primarily associated with the production and utilization of energy. However, currently, the primary cause of OA development and progression is not clear. In addition, although OA is manifested as a joint disease, evidence has accumulated that it affects the whole body. As pathological insulin resistance is viewed as a driving force of T2D development, now, we present evidence that the molecular and cellular metabolic disturbances associated with OA are linked to an insulin-resistant state similar to T2D. Moreover, the alterations in cellular energy requirements associated with insulin resistance could affect many metabolic changes in the body that eventually result in pathology and could serve as a unified mechanism that also functions in many metabolic diseases. However, these issues have not been comprehensively described. Therefore, here, we discuss the basic molecular mechanisms underlying the pathological processes associated with the development of insulin resistance; the major inducers, regulators, and metabolic consequences of insulin resistance; and instruments for controlling insulin resistance as a new approach to therapy.

Ameliorative effect of naringin against thiram-induced tibial dyschondroplasia in broiler chicken

Tetramethyl thiuram disulfide (thiram) is widely used in agricultural production as an insecticide and fungicide, which can also lead to tibial dyschondroplasia (TD) in poultry. TD is characterized by leg disorders and growth performance retardation, and no targeted drugs have been found to treat TD until now. Therefore, the objective of the present study was to explore the ameliorative effect of traditional Chinese medicine naringin on thiram-induced TD chickens. A total of 180 one-day-old Arbor Acres (AA) broiler chickens were randomly divided into three equal groups (n = 60): control group (standard diet), thiram-induced group (thiram 50 mg/kg from day 3 to day 7), and naringin-treated group (naringin 30 mg/kg from day 8 to day 18). During the 18-day experiment, the growth performance, tibial bone parameters, antioxidant property of liver, serum biochemical changes and clinical symptoms were recorded to evaluate the protective effect of naringin in thiram-induced TD broiler chickens. Additionally, mRNA expressions and protein levels of Ihh and PTHrP genes were determined via quantitative real-time polymerase chain reaction and western blot. Administration of naringin showed significant results by alleviating lameness, increased growth performance, recuperated growth plate (GP) width, and improved functions and antioxidant enzyme level of liver in broilers affected by TD. Moreover, naringin treatment restored the development of damaged tibia bone via downregulating Ihh and upregulating PTHrP mRNA and protein expressions. In conclusion, our study determines naringin could be used as an effective medicine to treat TD.

Where ferroptosis inhibitors and paraquat detoxification mechanisms intersect, exploring possible treatment strategies

Paraquat (PQ) is a fast-acting and effective herbicide that is used throughout the world to eliminate weeds. Over the past years, PQ was considered one of the most popular poisoning substances for suicide, and PQ poisoning accounts for about one-third of suicides around the world. Poisoning with PQ may cause multiorgan failure, pulmonary fibrosis, and ultimately death. Exposure to PQ results in the accumulation of PQ in the lungs, causing severe damage and, eventually, fibrosis. Until now, no effective antidote has been found to treat poisoning with PQ. In general, the toxicity of PQ is due to the formation of high energy oxygen free radicals and the peroxidation of unsaturated lipids in the cell. Ferroptosis is the result of the loss of glutathione peroxidase 4 (GPX4) activity that transforms iron-dependent lipid hydroperoxides to lipid alcohols, which are inert in the biological environment. Impaired iron metabolism and lipid peroxidation are increasingly known as the driving agents of ferroptosis. The contribution of ferroptosis to the development of cell death during poisoning with PQ has not yet been addressed. There is growing evidence about the relationship between PQ poisoning and ferroptosis. This raises the possibility of using ferroptosis inhibitors for the treatment of PQ poisoning. In this hypothesis-driven review article, we elaborated how ferroptosis inhibitors might circumvent the toxicity induced by PQ and may be potentially useful for the treatment of PQ toxicity.

Saxagliptin protects against hypoxia-induced damage in H9c2 cells

Type II diabetes is recognized as a major risk factor for death due to cardiovascular complications such as coronary heart disease (CHD), but the complex interplay between these two diseases remains poorly understood. Suppression of oxidative stress, apoptosis, and inflammation of endothelial cells is a valuable treatment strategy to prevent or halt the progression of CHD. In the present study, we used real-time polymerase chain reaction (PCR), Western blot analysis, and enzyme linked immunosorbent assay (ELISA) to investigate the effects of saxagliptin on hypoxia-inducible factors. Our findings demonstrate that saxagliptin can significantly improve cell viability in H9c2 cells as well as reduce hypoxia-induced oxidative damage and loss of mitochondrial membrane potential. Saxagliptin reduced hypoxia-induced NADPH oxidase 4 (NOX 4). We also show that saxagliptin can reduce the expression of matrix metallopeptidase-2 (MMP-2) and matrix metallopeptidase-9 (MMP-9), two important degradative enzymes. Saxagliptin also suppressed hypoxia-induced expression of high mobility group box-1 protein (HMGB1), a key inflammatory cytokine. Finally, we show that saxagliptin can exert atheroprotective effects by reducing the expression of myeloid differential protein-88 (MyD88) and increasing the expression of nuclear factor erythroid-2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1). Thus, saxagliptin shows promise as a treatment against diabetes-associated CHD.