Curcumin exerts chondroprotective effects against osteoarthritis by promoting AMPK/PINK1/Parkin-mediated mitophagy

Mitophagy in acute central nervous system injuries: regulatory mechanisms and therapeutic potentials

Acute central nervous system injuries, including ischemic stroke, intracerebral hemorrhage, subarachnoid hemorrhage, traumatic brain injury, and spinal cord injury, are a major global health challenge. Identifying optimal therapies and improving the long-term neurological functions of patients with acute central nervous system injuries are urgent priorities. Mitochondria are susceptible to damage after acute central nervous system injury, and this leads to the release of toxic levels of reactive oxygen species, which induce cell death. Mitophagy, a selective form of autophagy, is crucial in eliminating redundant or damaged mitochondria during these events. Recent evidence has highlighted the significant role of mitophagy in acute central nervous system injuries. In this review, we provide a comprehensive overview of the process, classification, and related mechanisms of mitophagy. We also highlight the recent developments in research into the role of mitophagy in various acute central nervous system injuries and drug therapies that regulate mitophagy. In the final section of this review, we emphasize the potential for treating these disorders by focusing on mitophagy and suggest future research paths in this area.

Suppressive effect of curcumin on apoptosis of articular chondrocytes via regulation on NF-κB pathway and NLRP3 inflammasome

Our study probed into how curcumin modulates NF-κB pathway to regulate articular chondrocytes. ATDC5 cells were exposed to varying concentrations of curcumin (0, 10, 20, 50, or 100 μM) for 48 h, followed by an assessment of curcumin's cytotoxicity. Cells were also treated with 10 ng/ml IL-1β, curcumin, 5 μg/L NF-κB inhibitor (PDTC), and 5 μM NLRP3 inflammasome inducer (nigericin) for 48 h, before cell viability, apoptosis, NF-κB pathway-related proteins, NLRP3 inflammasome-related proteins and inflammatory cytokines were detected. IL-1β treatment notably diminished chondrocyte viability and increased apoptosis, evidenced by elevated level of Bax and cleaved caspase-3, and reduced level of Bcl2, while such expression patterns were reversed by curcumin treatment in a concentration-dependent fashion. Additionally, NF-κB pathway and NLRP3 inflammasome in chondrocytes were activated by IL-1β treatment, but can also be suppressed following curcumin intervention. Furthermore, inhibition of NF-κB pathway curtailed the NLRP3 inflammasome activation and chondrocyte apoptosis, while activation of the NLRP3 inflammasome partially reversed the protective impacts of curcumin against chondrocyte apoptosis. Curcumin inhibits NF-κB pathway, thereby preventing the NLRP3 inflammasome activation and ameliorating IL-1β-induced apoptosis in articular chondrocytes.

Intra-articular injection of inorganic pyrophosphate improves IL-1β-induced cartilage damage in rat model of knee osteoarthritis in vivo

Objective

Osteoarthritis (OA) is the most common form of chronic joint disease, affecting mainly the elderly population. This disorder is caused by cartilage degeneration with complex changes in the chondrocyte phenotype. Inorganic pyrophosphate (PPi) was shown to counteract the detrimental effect of interleukin (IL)-1β challenging in an in vitro OA model based on rat articular chondrocytes. It also maintained the differentiated articular phenotype, mostly by down regulating wingless-related integration site (Wnt)-5a secretion. These observations suggest a PPi protective role for chondrocyte in vitro.

Methods

To address this hypothesis in vivo, we investigated the impact on knee joint of three intra-articular injection (IAI) of PPi in a rat model of cartilage damage induced by IAI of IL-1β, where cartilage degradation and synovial inflammation are similar to that observed in OA. Cartilage and synovial membrane were collected after 7 days of challenge by IL-1β.

Results

PPi was able to reduce the deleterious effect of IL-1β. This effect was observable on the expression of cartilage extracellular matrix metabolism markers and confirmed by histology with safranin O and hematoxylin-eosin-saffron (HES) staining. Inorganic pyrophosphate also repressed the Wnt5a expression induced by IL-1β. No effect was observed on the inflammatory response of the synovial membrane.

Conclusion

These results demonstrate that PPi improves IL-1β-induced cartilage damage in rat but not the associated inflammation of synovial membrane. Thus, PPi could become a molecule of interest to restrict the progression of this disorder.

sdRNA-D43 derived from small nucleolar RNA snoRD43 improves chondrocyte senescence and osteoarthritis progression by negatively regulating PINK1/Parkin-mediated mitophagy pathway via dual-targeting NRF1 and WIPI2

BACKGROUND

Chondrocyte senescence play an essential role in osteoarthritis (OA) progression. Recent studies have shown that snoRNA-derived RNA fragments (sdRNAs) are novel regulators of post-transcriptional gene expression. However, the expression profiles and their role in post-transcriptional gene regulation in chondrocyte senescence and OA progression is unknown. Here, we determined sdRNAs expression profile and explored sdRNA-D43 role in OA and its mechanism.

METHODS

We used qPCR arrays to determine sdRNAs expression in the chondrocytes of areas undamaged and damaged of the three knee OA samples. SdRNA-D43 expression was determined using quantitative reverse transcription-polymerase chain reaction and in situ hybridization. Then, bioinformatics analysis was conducted on the target genes that might be silenced by sdRNA-D43. Primary chondrocytes of damaged regions of knee OA samples were transfected with a sdRNA-D43 inhibitor or mimic to determine their functions, including in relation to mitophagy and chondrocyte senescence. Argonaute2-RNA immunoprecipitation and luciferase reporter assays were conducted to determine the target gene of sdRNA-D43. In a rat OA model induced by monosodium iodoacetate, adeno-associated virus sh-rat-sdRNA-D43 was injected into the knee joint cavity to assess its in vivo effects.

RESULTS

sdRNA-D43 expression were upregulated in damaged areas of knee OA cartilage with increased senescent chondrocytes. sdRNA-D43 inhibited mitophagy and promoted chondrocytes senescence during OA progression. Mechanistically, sdRNA-D43 silenced the expression of both NRF1 and WIPI2 by binding to their 3'-UTR in an Argonaute2‑dependent manner, which inhibited PINK1/Parkin-mediated pathway. Additionally, injection of AAV-sh-sdRNA-D43 alleviated the progression of OA in a monosodium iodoacetate-induced rat model.

CONCLUSION

Our results reveal an important role for a novel sdRNA-D43 in OA progression. sdRNA-D43 improves chondrocyte senescence by negatively regulating PINK1/Parkin-mediated mitophagy pathway via dual-targeting NRF1 and WIPI2, which provide a potential therapeutic strategy for OA treatment.

Efficacy and Safety of a Novel Low-Dose Water-Dispersible Turmeric Extract in the Management of Knee Osteoarthritis: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial

Purpose

Turmeric extract is a well-known nutraceutical ingredient recognized for its benefits in managing musculoskeletal health. This study evaluated the efficacy and safety of a novel low-dose water-dispersible turmeric extract containing 60% natural curcuminoids (WDTE60N) in participants with mild-to-moderate knee osteoarthritis.

Patients and Methods

This double-blind, randomized, placebo-controlled trial was conducted at two orthopedic centers in Uttar Pradesh, India (July 2023-November 2023). Participants aged 45-75 years with unilateral or bilateral OA of the knee for >3 months were randomized in 1:1 ratio to receive WDTE60N (250 mg) or placebo capsules once daily for three months. Study endpoints included assessment of changes from baseline to day 90 in pain intensity (visual analog scale [VAS], knee injury and osteoarthritis outcome score [KOOS]), inflammatory biomarkers, and safety profile. Data were analyzed using independent t-test, chi-square test, and analysis of co-variance test.

Results

In total, 139 participants (WDTE60N, n = 70; placebo, n = 69) with mean age and BMI of 56.35 years and 23.89 kg/m2, respectively, were included. The mean reduction (95% CI) in VAS score from baseline to day 90 was significantly higher in the WDTE60N group than in the placebo group (14.41 [13.08, 15.75] vs 6.02 [5.00, 7.05]; p < 0.0001). In the WDTE60N group, the mean change in VAS scores was significantly reduced from as early as day 07 (p = 0.0076), which continued until day 90 (p < 0.0001), compared to the placebo group. Improvement in the mean KOOS scores (baseline-Day 90) was evident, with significantly higher mean scores for each domain (pain, symptoms, activities of daily living, function in sport and recreation, and knee-related quality of life [QoL]) on Day 90 in the WDTE60N group than in the placebo group (p < 0.05). Inflammatory biomarkers (hsCRP, TNF-α, IL-6, and IL-1β) were significantly reduced from baseline to day 90 in the WDTE60N group compared to the placebo group (p < 0.0001). Four mild adverse events were reported during the study period.

Conclusion

Supplementation with the low-dose water-dispersible turmeric extract containing 60% natural curcuminoids for three months was safe and effective in alleviating pain, improving functional status and quality of life and reducing inflammation in participants with mild-to-moderate knee osteoarthritis.

CTRI Registration Number

CTRI/2023/07/055411.

NLRP3 Inflammasome-Mediated Osteoarthritis: The Role of Epigenetics

The prevalence of osteoarthritis (OA) notably surges with age and weight gain. The most common clinical therapeutic drugs are painkillers, yet they cannot impede the deteriorating course of OA. Thus, understanding OA's pathogenesis and devising effective therapies is crucial. It is generally recognized that inflammation, pyroptosis, and OA progression are tightly linked. The activation of NLRP3 inflammasome can lead to the discharge of the pro-inflammatory cytokines Interleukin-1β and IL-18, intensifying subsequent inflammatory reactions and promoting OA development. Conversely, the imbalance caused by deacetylase-regulated NLRP3 inflammasome underlies the chronic mild inflammation related to degenerative diseases. Therefore, this article expounds on the mechanism of OA pathogenesis and the role of histone deacetylases (HDACs) in NLRP3 inflammasome-triggered OA, and illustrates the application of HDAC inhibitors in OA, striving to provide more insights into novel OA treatment approaches.

A potential therapeutic approach for ulcerative colitis: targeted regulation of mitochondrial dynamics and mitophagy through phytochemicals

Mitochondria are important organelles that regulate cellular energy and biosynthesis, as well as maintain the body's response to environmental stress. Their dynamics and autophagy influence occurrence of cellular function, particularly under stressful conditions. They can generate reactive oxygen species (ROS) which is a major contributor to inflammatory diseases such as ulcerative colitis (UC). In this review, we discuss the key effects of mitochondrial dynamics and mitophagy on the pathogenesis of UC, with a particular focus on the cellular energy metabolism, oxidative stress, apoptosis, and immunoinflammatory activities. The therapeutic efficacy of existing drugs and phytochemicals targeting the mitochondrial pathway are discussed to reveal important insights for developing therapeutic strategies for treating UC. In addition, new molecular checkpoints with therapeutic potential are identified. We show that the integration of mitochondrial biology with the clinical aspects of UC may generate ideas for enhancing the clinical management of UC.

Development of novel osteoarthritis therapy by targeting AMPK-β-catenin-Runx2 signaling

Osteoarthritis (OA) is a debilitating chronic joint disease affecting large populations of patients, especially the elderly. The pathological mechanisms of OA are currently unknown. Multiple risk factors are involved in OA development. Among these risk factors, alterations of mechanical loading in the joint leading to changes in biological signaling pathways have been known as a key event in OA development. The importance of AMPK-β-catenin-Runx2 signaling in the initiation and progression of OA has been recognized in recent years. In this review, we discuss the recent progress in understanding the role of this signaling pathway and the underlying interaction mechanisms during OA development. We also discuss the drug development aiming to target this signaling pathway for OA treatment.

Molecular mechanism of geniposide against ANIT-induced intrahepatic cholestasis by integrative analysis of transcriptomics and metabolomics

Geniposide (GE), a bioactive compound extracted from the fruit of Gardenia jasminoides Ellis, has attracted significant attention for its hepatoprotective therapeutic applications. Although GE displays a protective effect on treating intrahepatic cholestasis (IC), the underlying mechanism remains elusive. In this study, we aimed to elucidate the pharmacological mechanisms of GE in treating IC by an integrated analysis of transcriptomics and metabolomics. Firstly, we evaluated the hepatoprotective effect of GE in α-naphthylisothiocyanate (ANIT)-induced IC rats by examining biochemical indices, inflammatory factors, and oxidative stress levels. Secondly, by transcriptomics and serum metabolomics, we identified differentially expressed genes and metabolites, revealing phenotype-related metabolic pathways and gene functions. Lastly, we screened the core targets of GE in the treatment of IC by integrating transcriptomic and metabolomic data and validated these targets using western blotting. The results indicated that GE improved serum indexes and alleviated inflammation reactions and oxidative stress in the liver. The transcriptomics analysis revealed 739 differentially expressed genes after GE treatment, mainly enriched in retinol metabolism, steroid hormone synthesis, PPAR signal transduction, bile secretion metabolism, and other pathways. The metabolomics analysis identified 98 differential metabolites and 10 metabolic pathways. By constructing a "genes-targets-pathways-compounds" network, we identified two pathways: the bile secretion pathway and the glutathione pathway. Within these pathways, we discovered nine crucial targets that were subsequently validated through western blotting. The results revealed that the GE group significantly increased the expression of ABCG5, NCEH1, OAT3, and GST, compared with the ANIT group. We speculate that GE has a therapeutic effect on IC by modulating the bile secretion pathway and the glutathione pathway and regulating the expression of ABCG5, NCEH1, OAT3, and GST.

The effect of Miya on skeletal muscle changes by regulating gut microbiota in rats with osteoarthritis through AMPK pathway

BACKGROUND

The study aimed to explore whether Miya (MY), a kind of Clostridium butyricum, regulated osteoarthritis (OA) progression through adenosine 5'-monophosphate-activated protein kinase (AMPK) pathway.

METHODS

The OA rats were orally given MY daily for 4 weeks and were intramuscularly injected with AMPK inhibitor once a week for 4 weeks. Hematoxylin eosin (HE) staining was used to observe the histological morphology of the knee joint. The levels of succinate dehydrogenase (SDH) and muscle glycogen (MG) in the tibia muscle of rats were detected by the corresponding kits, as well as the expression of related genes/proteins were assessed by real-time quantitative PCR (RT-qPCR) and western blot.

RESULTS

HE staining suggested that MY suppressed the symptoms of OA, which was abolished by AMPK inhibitor. Furthermore, the SDH and MG contents in the OA + MY + AMPK inhibitor group were lower than in the OA + MY group. At last, the levels of AMPK, PI3K, AKT1, Ldh, Myod, Chrna1, and Chrnd were notably decreased after AMPK inhibitor treatment, while the levels of Lcad and Mcad were up-regulated by AMPK inhibitor. Furthermore, their protein expression levels detected by western blot were consistent with those from RT-qPCR.

CONCLUSION

MY may partially regulate skeletal muscle changes and prevente OA development through the AMPK pathway.

Curcumin liposomes alleviate senescence of bone marrow mesenchymal stem cells by activating mitophagy

The senescence of mesenchymal stem cells (MSCs) is closely related to aging and degenerative diseases. Curcumin exhibits antioxidant and anti-inflammatory effects and has been extensively used in anti-cancer and anti-aging applications. Studies have shown that curcumin can promote osteogenic differentiation, autophagy and proliferation of MSCs. Liposome, as a nano-carrier, provides a feasible strategy for improving the bioavailability and controlled-release profile of curcumin.This study aimed to evaluate the effects of curcumin liposomes (Cur-Lip) on the senescence of rat bone marrow mesenchymal stem cells (rBMSCs). Based on network pharmacology, we predicted the targets and mechanisms of curcumin on senescence of MSC. 23 key targets of Cur were associated with MSC senescence were screened out and mitophagy signaling was significantly enriched. Cur-Lip treatment alleviated senescence of D-galactose (D-gal)-induced rBMSCs, protected mitochondrial function, and activated mitophagy, which may be related to mitochondrial fission. Inhibition of mitophagy attenuated the protective effects of Cur-lip on mitochondrial function and senescence of rBMSCs. Our findings suggested that Cur-Lip could alleviate senescence of rBMSC and improve mitochondrial function by activating mitophagy.

Targeted non-invasive Metformin-Curcumin co-loaded nanohyaluosomes halt osteoarthritis progression and improve articular cartilage structure: A preclinical study

Osteoarthritis (OA) is a degenerative disease that affects the quality of life in elderly and young populations. Current therapies using corticosteroids and non-steroidal anti-inflammatory drugs via parenteral or oral routes show limited ability to retard progression of the disease and achieve long term effectiveness and safety. Herein, the potential of MT-Cur combinatorial nano-formulations in OA management was explored for the first time. MT-Cur loaded nanohyaluosomes (MT-Cur-HL1) were designed for topical administration of the combined therapy in OA. The optimized MT-Cur-HL1 showed particle size 247.7 ± 3.7 nm, zeta potential -37.3 ± 0.4 mV; and entrapment efficiency (%EE) 70.22 %±0.303 and 76.7 %±0.077 for MT and Cur, respectively. MT-Cur-HL1 exhibited sustained drug release over 24 h and were stable over 3 months at 4 °C in terms of P.S., ZP and %EE. A detailed preclinical study, using MIA-induced osteoarthritis rat model, revealed the most significant anti-arthritic effect and halted OA progression of MT-Cur-HL1. This was proved to be mainly through the potentiation of p-AMPK signaling that ultimately led to suppression of its downstream TLR4/ NF-κB signaling pathway with subsequent reduction in MMP13 and ADAMTS5 induced chondrocytes degeneration. This study proved that this trajectory effectively promotes a significant improvement in the articular cartilage structure and reinforcement of joint mobility with an efficient antinociceptive effect. In conclusion, the novel MT-Cur coloaded nanohyaluosomes offer a promising non-invasive approach for the local management of OA.

Astaxanthin mediated repair of tBHP-Induced cellular injury in chondrocytes

OBJECTIVE

This study investigates how astaxanthin (AST) counters tert-butyl hydroperoxide (tBHP)-induced cellular damage in C28/I2 chondrocytes, focusing on the circ-HP1BP3/miR-139-5p/SOD1 signaling pathway and its use in sustained-release microspheres for osteoarthritis treatment.

METHODS

We employed a variety of techniques including real-time quantitative PCR, Western blot, ELISA, and dual-luciferase reporter gene assays to explore AST's molecular effects. Additionally, the efficacy of AST-loaded sustained-release microspheres was evaluated in vitro and in a mouse model of osteoarthritis.

RESULTS

AST significantly enhanced SOD1 expression, reducing apoptosis and inflammation in damaged cells. The AST-loaded microspheres showed promising in vitro drug release, improved cell viability, and reduced oxidative stress. In the osteoarthritis mouse model, they effectively decreased joint inflammation and increased the expression of chondrocyte markers.

CONCLUSION

Astaxanthin effectively mitigates oxidative stress and inflammation in chondrocytes via the circ-HP1BP3/miR-139-5p/SOD1 pathway. The development of AST-loaded microspheres offers a novel and promising approach for osteoarthritis therapy, potentially extending to osteoarthritis treatment.

Mitochondria in skeletal system-related diseases

Skeletal system-related diseases, such as osteoporosis, arthritis, osteosarcoma and sarcopenia, are becoming major public health concerns. These diseases are characterized by insidious progression, which seriously threatens patients' health and quality of life. Early diagnosis and prevention in high-risk populations can effectively prevent the deterioration of these patients. Mitochondria are essential organelles for maintaining the physiological activity of the skeletal system. Mitochondrial functions include contributing to the energy supply, modulating the Ca2+ concentration, maintaining redox balance and resisting the inflammatory response. They participate in the regulation of cellular behaviors and the responses of osteoblasts, osteoclasts, chondrocytes and myocytes to external stimuli. In this review, we describe the pathogenesis of skeletal system diseases, focusing on mitochondrial function. In addition to osteosarcoma, a characteristic of which is active mitochondrial metabolism, mitochondrial damage occurs during the development of other diseases. Impairment of mitochondria leads to an imbalance in osteogenesis and osteoclastogenesis in osteoporosis, cartilage degeneration and inflammatory infiltration in arthritis, and muscle atrophy and excitationcontraction coupling blockade in sarcopenia. Overactive mitochondrial metabolism promotes the proliferation and migration of osteosarcoma cells. The copy number of mitochondrial DNA and mitochondria-derived peptides can be potential biomarkers for the diagnosis of these disorders. High-risk factor detection combined with mitochondrial component detection contributes to the early detection of these diseases. Targeted mitochondrial intervention is an effective method for treating these patients. We analyzed skeletal system-related diseases from the perspective of mitochondria and provided new insights for their diagnosis, prevention and treatment by demonstrating the relationship between mitochondria and the skeletal system.

Parkin deficiency aggravates inflammation-induced acute lung injury by promoting necroptosis in alveolar type II cells

Background

Necroptosis is a form of programmed cell death resulting in tissue inflammation due to the release of intracellular contents. Its role and regulatory mechanism in the context of acute lung injury (ALI) are unclear. Parkin (Prkn), an E3 ubiquitin ligase, has recently been implicated in the regulation of necroptosis. In this study, we aimed to investigate the role and mechanism of Parkin in the process of ALI.

Methods

Lipopolysaccharides (LPS)-induced mouse ALI model was utilized, and the pathological changes in lung tissues were characterized. To elucidate the roles of Parkin and necroptosis in this context, mixed lineage kinase domain-like (Mlkl) knockout mice, Prkn conditional knockout mice, and the necroptosis inhibitor were employed. Additionally, alveolar type 2 (AT2) cell-specific Parkin deletion and lineage-tracing mice were introduced to explore the specific roles and mechanisms of Parkin in AT2 cells.

Results

A dose-dependent increase in Parkin expression in mouse lung tissues following LPS administration was observed, correlating with a shift from epithelial apoptosis to necroptosis. Notably, depletion of MLKL significantly mitigated the pathological changes associated with ALI, particularly the inflammatory response. Conversely, the deletion of Parkin exacerbated the injury pathology, significantly enhancing necroptosis, particularly in AT2 cells. This led to increased inflammation and post-LPS fibrosis. However, treatment with GSK872, a necroptosis inhibitor, substantially mitigated the phenotype induced by Parkin deletion. Importantly, Parkin deletion impaired the proliferation and differentiation of AT2 cells into AT1 cells.

Conclusions

These findings underscore the multifaceted role of Parkin in the progression of lung injury, inflammation, and fibrosis through the regulation of AT2 cell necroptosis. Therefore, Parkin may hold potential as a therapeutic target for managing lung injury and fibrosis.

Identification of mitophagy-related biomarkers in osteoarthritis

BACKGROUND

Osteoarthritis (OA) is a common joint disease, and existing drugs cannot cure OA, so there is an urgent need to identify new targets. Mitophagy plays an important role in OA; however, the role of mitophagy in the OA immune system is not yet clear.

METHODS

In this study, differential analysis and enrichment analysis were used to identify mitophagy-related genes (MRGs) with differential expression in OA and the functional pathways involved in OA. Subsequently, two machine learning methods, RF and LASSO, were used to screen MRGs with diagnostic value and construct nomograms. At the same time, the relationship between mitophagy and OA immune response was explored by immunoinfiltration analysis.

RESULTS

Forty-three differentially MRGs were identified in OA, of which six MRGs (GABARAPL2, PARL, GABARAPL1, JUN, RRAS, and SNX7) were associated with the diagnosis of OA. The ROC analysis results show that these 6 MRGs have high predictive accuracy in the diagnosis of OA. In immune infiltration analysis, we found that the abundance of significantly different immune cells in OA was mostly upregulated. In addition, the expression of diagnostic-related MRGs is correlated with changes in the abundance of immune cells in OA.

CONCLUSION

This study demonstrates that six MRGs can be used as diagnostic biomarkers. The expression of diagnostic-related MRGs is correlated with changes in the abundance of immune cells in OA. At the same time, mitophagy may affect the immune microenvironment of OA by regulating immune cells, ultimately leading to the progression of OA.

Therapeutic potential of Parkin and its regulation in Parkinson's disease

Parkinson's disease (PD) is a debilitating neurodegenerative disorder characterized by the progressive loss of dopaminergic neurons in the midbrain substantia nigra, resulting in motor and non-motor symptoms. While the exact etiology of PD remains elusive, a growing body of evidence suggests that dysfunction in the parkin protein plays a pivotal role in the pathogenesis of the disease. Parkin is an E3 ubiquitin ligase that ubiquitinates substrate proteins to control a number of crucial cellular processes including protein catabolism, immune response, and cellular apoptosis.While autosomal recessive mutations in the PARK2 gene, which codes for parkin, are linked to an inherited form of early-onset PD, heterozygous mutations in PARK2 have also been reported in the more commonly occurring sporadic PD cases. Impairment of parkin's E3 ligase activity is believed to play a pathogenic role in both familial and sporadic forms of PD.This article provides an overview of the current understanding of the mechanistic basis of parkin's E3 ligase activity, its major physiological role in controlling cellular functions, and how these are disrupted in familial and sporadic PD. The second half of the manuscript explores the currently available and potential therapeutic strategies targeting parkin structure and/or function in order to slow down or mitigate the progressive neurodegeneration in PD.

PINK1/Parkin-Mediated Mitophagy Ameliorates Mitochondrial Dysfunction in Lacrimal Gland Acinar Cells During Aging

Purpose

Aging alters the function of the lacrimal gland and disrupts the balance of the microenvironment on the ocular surface, eventually leading to aqueous-tear-deficient dry eye. Mitophagy has been reported to play an important role in aging, but the underlying mechanism remains unclear.

Methods

The young (6 weeks) and middle-aged (12 months) male C57BL/6J mice were used in this study, and mitophagy agonist rapamycin and inhibitor Mdivi-1 were used in in vivo experiments. Hematoxylin and eosin, Masson, Oil Red O, and reactive oxygen species (ROS) staining were used to detect histological changes and lipids in lacrimal gland. Changes in the expression of proteins were identified by Western blotting of lacrimal gland lysates. Transmission electron microscopy and immunofluorescence staining were used to assess mitophagy. The single-cell RNA sequencing (scRNA-seq) and bioinformatics analyses were used to detect transcription signature changes during aging.

Results

In this study, we discovered that aging increased oxidative stress, which increased apoptosis, and generated ROS in acinar epithelial cells. Furthermore, activation of PINK1/Parkin-mediated mitophagy by rapamycin reduced lacrimal gland ROS concentrations and prevented aging-induced apoptosis of acinar cells, thereby causing histological alterations, microstructural degradation, and increasing tear secretion associated with ROS accumulation. By contrast, Mdivi-1 aggregates mitochondrial function and thereafter leads to lacrimal gland function impairment by inhibiting mitochondrial fission and giving rise to mitophagy.

Conclusions

Overall, our findings suggested that aging could impair mitochondrial function of acinar cells, and age-related alterations may be treated with therapeutic approaches that enhance mitophagy while maintaining mitochondrial function.

Novel formulations ameliorate osteoarthritis in rats by inhibiting inflammation and oxidative stress

The study tested new oral plant-based formulations (F) on rats with monosodium iodoacetate (MIA)-induced osteoarthritis, measuring inflammation, antioxidant levels, paw size, stride, and analyzing knee joint images. Fifty-six female Sprague Dawley rats were allocated into 8 groups: (1) Control, (2) MIA (OA induced with MIA), (3) MIA + F1 [curcuminoids+gingerols+acetyl-11-keto-β boswellic acid (AKBA)], (4) MIA + F2 (curcuminoids+Withania glycosides+AKBA), (5) MIA + F3 (curcuminoids+total withanolides+AKBA), (6) MIA + F4 (curcuminoids, AKBA), (7) MIA + UCII (type II collagen), and (8) MIA + GCHON (Glucosamine Chondroitin). Treatments F1 to F4 reduced right joint diameter and improved stride length and paw area in OA rats. Despite improvements with treatments F1 to F4, there was no significant difference between these groups (p > .05). In OA animals, F1 to F4 treatments decreased MDA levels and increased antioxidant enzymes activities (p < .001). This was done by reducing levels of inflammatory markers and enzymes like IL-1β, IL-6, MMP-8, TNF-α, CRP, COMP, and LOX-5, while increasing the anti-inflammatory cytokine IL-10. In conclusion, these plant-based treatments significantly reduced osteoarthritis severity, slowed disease progression by reducing inflammation, and protected joints from damage, showing a protective effect in rats with induced osteoarthritis, likely due to their anti-inflammatory and antioxidant properties.

New insights into the mechanisms and therapeutic strategies of chondrocyte autophagy in osteoarthritis

Osteoarthritis (OA) is a chronic joint disease with an unclear cause characterized by secondary osteophytes and degenerative changes in the articular cartilage. More than 250 million people are expected to be affected by it by 2050, putting a tremendous socioeconomic strain on the entire world. OA cannot currently be treated with any effective medications that change the illness. Over time, chondrocytes undergo gradual metabolic, structural, and functional changes as a result of aging or abuse. The degenerative progression of osteoarthritis is significantly influenced by the imbalance of chondrocyte homeostasis. By continuously recycling and rebuilding macromolecules or organelles, autophagy functions as a crucial regulatory system to maintain homeostasis during an individual's growth and development. This review uses chondrocytes as its starting point and establishes a strong connection between autophagy and osteoarthritis in order to thoroughly examine the mechanisms behind chondrocyte autophagy in osteoarthritis. Biomarkers of chondrocyte autophagy will be identified, and prospective targeted medications and novel treatment approaches for slowing or preventing the course of OA will be developed based on chondrocyte senescence, autophagy, and apoptosis in OA. KEY MESSAGES: Currently, OA has not been treated with any drugs that can effectively cure it. We hope that by exploring specific targets in the course of osteoarthritis, we can promote the progress of treatment strategies. The degenerative progression of osteoarthritis is significantly influenced by the imbalance of chondrocyte balance. Through the continuous recovery and reconstruction of macromolecules or organelles, autophagy is an important regulatory system for maintaining homeostasis during individual growth and development. In this paper, the close relationship between autophagy and osteoarthritis was established with chondrocytes as the starting point, in order to further explore the mechanism of chondrocyte autophagy in osteoarthritis. The development process of osteoarthritis was studied from the perspective of chondrocytes, and the change of autophagy level had a significant impact on osteoarthritis. Chondrocyte autophagy is mainly determined by intracellular mitochondrial autophagy, so we are committed to finding relevant molecules. Through PI3K/AKT- and MAPK-related pathways, the biomarkers of chondrocyte autophagy were identified, and chondrocyte senescence, autophagy, and apoptosis based on osteoarthritis provided a constructive idea for the development of prospective targeted drugs and new therapies to slow down or prevent the progression of osteoarthritis.

Integrating network pharmacology and experimental validation to explore the mitophagy-associated pharmacological mechanism of modified Shisiwei Jianzhong decoction against aplastic anemia

The aim of this work was to investigate the therapeutic effect of modified Shisiwei Jianzhong Decoction (SJD) on aplastic anemia (AA) and its potential pharmacological mechanism from the perspective of mitophagy. A comprehensive approach combining network pharmacology, mendelian randomization, molecular docking and animal experiments was applied to evaluate the properties of SJD against AA. By integrating multiple databases, it was determined that SJD exerted its therapeutic effect on AA by targeting three key targets [mammalian target of rapamycin (MTOR), poly(ADP-ribose) polymerase 1 (PARP1) and Sirtuin 1 (SIRT1)] through four core compounds (quercetin, resveratrol, genistein and curcumin). Mendelian randomization analysis identified MTOR as a risk factor for AA occurrence while PARP1 was a protective factor. Results of animal experiments showed that SJD improved peripheral blood counts and promoted the proliferation of hematopoietic stem cells. Mechanistically, SJD, especially at high dose, played a therapeutic role in AA by activating mitophagy-related proteins PTEN induced kinase 1 (PINK1)/Parkin and inhibiting the phosphatidylinositol 3-kinase (PI3K)/protein kinase (AKT)/MTOR pathway. This study revealed for the first time the core chemical composition of SJD and its pharmacological effects against AA, which can restore hematopoietic function by activating mitophagy. The results provide inspiration for the clinical application of traditional Chinese medicine in AA treatment.

Natural Autophagy Activators to Fight Age-Related Diseases

The constant increase in the elderly population presents significant challenges in addressing new social, economic, and health problems concerning this population. With respect to health, aging is a primary risk factor for age-related diseases, which are driven by interconnected molecular hallmarks that influence the development of these diseases. One of the main mechanisms that has attracted more attention to aging is autophagy, a catabolic process that removes and recycles damaged or dysfunctional cell components to preserve cell viability. The autophagy process can be induced or deregulated in response to a wide range of internal or external stimuli, such as starvation, oxidative stress, hypoxia, damaged organelles, infectious pathogens, and aging. Natural compounds that promote the stimulation of autophagy regulatory pathways, such as mTOR, FoxO1/3, AMPK, and Sirt1, lead to increased levels of essential proteins such as Beclin-1 and LC3, as well as a decrease in p62. These changes indicate the activation of autophagic flux, which is known to be decreased in cardiovascular diseases, neurodegeneration, and cataracts. The regulated administration of natural compounds offers an adjuvant therapeutic alternative in age-related diseases; however, more experimental evidence is needed to support and confirm these health benefits. Hence, this review aims to highlight the potential benefits of natural compounds in regulating autophagy pathways as an alternative approach to combating age-related diseases.

Exploring the impact of curcumin on osteoarthritis symptomatology: correlations and insights from a Bulgarian cohort

INTRODUCTION

Osteoarthritis is a prevalent degenerative joint disorder associated with pain and functional impairment. Curcumin, a natural anti-inflammatory compound, has garnered attention for its potential therapeutic benefits in osteoarthritis management.

Ferulic acid restores mitochondrial dynamics and autophagy via AMPK signaling pathway in a palmitate-induced hepatocyte model of metabolic syndrome

Mitochondrial dysfunction, characterized by elevated oxidative stress, impaired energy balance, and dysregulated mitochondrial dynamics, is a hallmark of metabolic syndrome (MetS) and its comorbidities. Ferulic acid (FA), a principal phenolic compound found in whole grains, has demonstrated potential in ameliorating oxidative stress and preserving energy homeostasis. However, the influence of FA on mitochondrial health within the context of MetS remains unexplored. Moreover, the impact of FA on autophagy, which is essential for maintaining energy homeostasis and mitochondrial integrity, is not fully understood. Here, we aimed to study the mechanisms of action of FA in regulating mitochondrial health and autophagy using palmitate-treated HepG2 hepatocytes as a MetS cell model. We found that FA improved mitochondrial health by restoring redox balance and optimizing mitochondrial dynamics, including biogenesis and the fusion/fission ratio. Additionally, FA was shown to recover autophagy and activate AMPK-related cell signaling. Our results provide new insights into the therapeutic potential of FA as a mitochondria-targeting agent for the prevention and treatment of MetS.

Human adipose and synovial-derived MSCs synergistically attenuate osteoarthritis by promoting chondrocyte autophagy through FoxO1 signaling

BACKGROUND

Human adipose-derived stem cells (ADSCs) exert a strong anti-inflammatory effect, and synovium-derived stem cells (SDSCs) have high chondrogenic potential. Thus, this study aims to investigate whether a combination of human ADSCs and SDSCs will have a synergistic effect that will increase the chondrogenic potential of osteoarthritis (OA) chondrocytes in vitro and attenuate the cartilage degeneration of early and advanced OA in vitro.

METHODS

ADSCs, SDSCs, and chondrocytes were isolated from OA patients who underwent total knee arthroplasty. The ADSCs-SDSCs mixed cell ratios were 1:0 (ADSCs only), 8:2, 5:5 (5A5S), 2:8, and 0:1 (SDSCs only). The chondrogenic potential of the OA chondrocytes was evaluated in vitro with a transwell assay or pellet culture with various mixed cell groups. The mixed cell group with the highest chondrogenic potential was then selected and injected into the knee joints of nude rats of early and advanced OA stages in vivo. The animals were then evaluated 12 and 20 weeks after surgery through gait analysis, von frey test, microcomputed tomography, MRI, and immunohistochemical and histological analyses. Finally, the mechanisms underlying these findings were investigated through the RNA sequencing of tissue samples in vivo and Western blot of the OA chondrocyte autophagy pathway.

RESULTS

Among the MSCs treatment groups, 5A5S had the greatest synergistic effect that increased the chondrogenic potential of OA chondrocytes in vitro and inhibited early and advanced OA in vivo. The 5A5S group significantly reduced cartilage degeneration, synovial inflammation, pain sensation, and nerve invasion in subchondral nude rat OA, outperforming both single-cell treatments. The underlying mechanism was the activation of chondrocyte autophagy via the FoxO1 signaling pathway.

CONCLUSION

A combination of human ADSCs and SDSCs demonstrated higher potential than a single type of stem cell, demonstrating potential as a novel treatment for OA.

Mycoplasma pneumoniae-induced Kawasaki disease via PINK1/Parkin-mediated mitophagy

Kawasaki disease (KD) is a systemic vasculitis with an unknown cause that primarily affects children. The objective of this study was to explore the function and underlying mechanism of mitophagy in Mycoplasma pneumoniae (MP)-induced KD. To create MP-induced KD models, Human coronary endothelial cells (HCAECs) and DBA/2 mice were employed and treated with Mp-Lipid-associated membrane proteins （LAMPs）. Lactate dehydrogenase (LDH) levels were tested to determine cellular damage or death. The inflammatory cytokines tumor necrosis factor (TNF)--α and interleukin (IL)-6 were measured using the Enzyme-Linked Immunosorbent Assay (ELISA) method. RT-qPCR and Western blotting were used to determine the expression of Intercellular Adhesion Molecule(ICAM)-1, vascular cell adhesion molecule (VCAM)-1, inducible nitric oxide synthase(iNOS), LC3, p62, PINK1(a mitochondrial serine/threonine-protein kinase), and PARKIN(a cytosolic E3-ubiquitin ligase). The adenosine triphosphate （ATP）, reactive oxygen species （ROS）, and mitochondrial membrane potential（MMP） levels were measured to determine mitochondrial function. Mitophagy was investigated using immunofluorescence and a mitophagy detection test. Autophagosome and mitochondrial morphology were examined using transmission electron microscopy. To identify inflammatory cell infiltration, hematoxylin and eosin staining was utilized. Mp-LAMPs increased the levels of TNF-α, IL-6, ICAM-1, VCAM-1, and iNOS in an HCAEC cell model, along with LDH release. After Mp-LAMPs exposure, there was a rise in LC3 and a reduction in p62. Meanwhile, the expression of PINK1 and Parkin was increased. Cyclosporin A dramatically increased ATP synthesis and MMP in HCAEC cells treated with Mp-LAMPs, while suppressing ROS generation, demonstrating excessive mitophagy-related mitochondrial dysfunction. Additionally, neither body weight nor artery tissue were affected due to PINK1 and Parkin suppression Cyclosporin A in Mp-LAMPs-treated mice. These findings indicated that PINK1/Parkin-mediated mitophagy inhibition may be a therapeutic target for MP-induced KD.

The Emerging Role of the Mitochondrial Respiratory Chain in Skeletal Aging

Maintenance of mitochondrial homeostasis is crucial for ensuring healthy mitochondria and normal cellular function. This process is primarily responsible for regulating processes that include mitochondrial OXPHOS, which generates ATP, as well as mitochondrial oxidative stress, apoptosis, calcium homeostasis, and mitophagy. Bone mesenchymal stem cells express factors that aid in bone formation and vascular growth. Positive regulation of hematopoietic stem cells in the bone marrow affects the differentiation of osteoclasts. Furthermore, the metabolic regulation of cells that play fundamental roles in various regions of the bone, as well as interactions within the bone microenvironment, actively participates in regulating bone integrity and aging. The maintenance of cellular homeostasis is dependent on the regulation of intracellular organelles, thus understanding the impact of mitochondrial functional changes on overall bone metabolism is crucially important. Recent studies have revealed that mitochondrial homeostasis can lead to morphological and functional abnormalities in senescent cells, particularly in the context of bone diseases. Mitochondrial dysfunction in skeletal diseases results in abnormal metabolism of bone-associated cells and a secondary dysregulated microenvironment within bone tissue. This imbalance in the oxidative system and immune disruption in the bone microenvironment ultimately leads to bone dysplasia. In this review, we examine the latest developments in mitochondrial respiratory chain regulation and its impacts on maintenance of bone health. Specifically, we explored whether enhancing mitochondrial function can reduce the occurrence of bone cell deterioration and improve bone metabolism. These findings offer prospects for developing bone remodeling biology strategies to treat age-related degenerative diseases.

Curcuminoid PBPD induces cuproptosis and endoplasmic reticulum stress in cervical cancer via the Notch1/RBP-J/NRF2/FDX1 pathway

Curcumin has been shown to have antitumor properties, but its low potency and bioavailability has limited its clinical application. We designed a novel curcuminoid, [1-propyl-3,5-bis(2-bromobenzylidene)-4-piperidinone] (PBPD), which has higher antitumor strength and improves bioavailability. Cell counting kit-8 was used to detect cell activity. Transwell assay was used to detect cell invasion and migration ability. Western blot and quantitative polymerase chain reaction were used to detect protein levels and their messenger RNA expression. Immunofluorescence was used to detect the protein location. PBPD significantly inhibited the proliferation of cervical cancer cells, with an IC50 value of 4.16 μM for Hela cells and 3.78 μM for SiHa cells, leading to the induction of cuproptosis. Transcriptome sequencing analysis revealed that PBPD significantly inhibited the Notch1/Recombination Signal Binding Protein for Immunoglobulin kappa J Region (RBP-J) and nuclear factor erythroid 2-related factor 2 (NRF2) signaling pathways while upregulating ferredoxin 1 (FDX1) expression. Knockdown of Notch1 or RBP-J significantly inhibited NRF2 expression and upregulated FDX1 expression, leading to the inhibition of nicotinamide adenine dinucleotide phosphate activity and the induction of oxidative stress, which in turn activated endoplasmic reticulum stress and induced cell death. The overexpression of Notch1 or RBP-J resulted in the enrichment of RBP-J within the NRF2 promoter region, thereby stimulating NRF2 transcription. NRF2 knockdown resulted in increase in FDX1 expression, leading to cuproptosis. In addition, PBPD inhibited the acidification of tumor niche and reduced cell metabolism to inhibit cervical cancer cell invasion and migration. In conclusion, PBPD significantly inhibits the proliferation, invasion, and migration of cervical cancer cells and may be a novel potential drug candidate for treatment of cervical cancer.

Recent advances in anti-inflammation via AMPK activation

Inflammation is a complex physiological phenomenon, which is the body's defensive response, but abnormal inflammation can have adverse effects, and many diseases are related to the inflammatory response. AMPK, as a key sensor of cellular energy status, plays a crucial role in regulating cellular energy homeostasis and glycolipid metabolism. In recent years, the anti-inflammation effect of AMPK and related signalling cascade has begun to enter everyone's field of vision - not least the impact on metabolic diseases. A great number of studies have shown that anti-inflammatory drugs work through AMPK and related pathways. Herein, this article summarises recent advances in compounds that show anti-inflammatory effects by activating AMPK and attempts to comment on them.

Research progresses on mitochondrial-targeted biomaterials for bone defect repair

In recent years, the regulation of the cell microenvironment has opened up new avenues for bone defect repair. Researchers have developed novel biomaterials to influence the behavior of osteoblasts and immune cells by regulating the microenvironment, aiming to achieve efficient bone repair. Mitochondria, as crucial organelles involved in energy conversion, biosynthesis and signal transduction, play a vital role in maintaining bone integrity. Dysfunction of mitochondria can have detrimental effects on the transformation of the immune microenvironment and the differentiation of stem cells, thereby hindering bone tissue regeneration. Consequently, targeted therapy strategies focusing on mitochondria have emerged. This approach offers a wide range of applications and reliable therapeutic effects, thereby providing a new treatment option for complex and refractory bone defect diseases. In recent studies, more biomaterials have been used to restore mitochondrial function and promote positive cell differentiation. The main directions are mitochondrial energy metabolism, mitochondrial biogenesis and mitochondrial quality control. In this review, we investigated the biomaterials used for mitochondria-targeted treatment of bone defect repair in recent years from the perspective of progress and strategies. We also summarized the micro-molecular mechanisms affected by them. Through discussions on energy metabolism, oxidative stress regulation and autophagy regulation, we emphasized the opportunities and challenges faced by mitochondria-targeted biomaterials, providing vital clues for developing a new generation of bone repair materials.

Pyroptosis: A spoiler of peaceful coexistence between cells in degenerative bone and joint diseases

BACKGROUND

As people age, degenerative bone and joint diseases (DBJDs) become more prevalent. When middle-aged and elderly people are diagnosed with one or more disorders such as osteoporosis (OP), osteoarthritis (OA), and intervertebral disc degeneration (IVDD), it often signals the onset of prolonged pain and reduced functionality. Chronic inflammation has been identified as the underlying cause of various degenerative diseases, including DBJDs. Recently, excessive activation of pyroptosis, a form of programed cell death (PCD) mediated by inflammasomes, has emerged as a primary driver of harmful chronic inflammation. Consequently, pyroptosis has become a potential target for preventing and treating DBJDs.

AIM OF REVIEW

This review explored the physiological and pathological roles of the pyroptosis pathway in bone and joint development and its relation to DBJDs. Meanwhile, it elaborated the molecular mechanisms of pyroptosis within individual cell types in the bone marrow and joints, as well as the interplay among different cell types in the context of DBJDs. Furthermore, this review presented the latest compelling evidence supporting the idea of regulating the pyroptosis pathway for DBJDs treatment, and discussed the potential, limitations, and challenges of various therapeutic strategies involving pyroptosis regulation.

KEY SCIENTIFIC CONCEPTS OF REVIEW

In summary, an interesting identity for the unregulated pyroptosis pathway in the context of DBJDs was proposed in this review, which was undertaken as a spoiler of peaceful coexistence between cells in a degenerative environment. Over the extended course of DBJDs, pyroptosis pathway perpetuated its activity through crosstalk among pyroptosis cascades in different cell types, thus exacerbating the inflammatory environment throughout the entire bone marrow and joint degeneration environment. Correspondingly, pyroptosis regulation therapy emerged as a promising option for clinical treatment of DBJDs.

The role and intervention of mitochondrial metabolism in osteoarthritis

Osteoarthritis (OA), a prevalent degenerative joint disease, affects a substantial global population. Despite the elusive etiology of OA, recent investigations have implicated mitochondrial dysfunction as a significant factor in disease pathogenesis. Mitochondria, pivotal cellular organelles accountable for energy production, exert essential roles in cellular metabolism. Hence, mitochondrial dysfunction can exert broad-ranging effects on various cellular processes implicated in OA development. This comprehensive review aims to provide an overview of the metabolic alterations occurring in OA and elucidate the diverse mechanisms through which mitochondrial dysfunction can contribute to OA pathogenesis. These mechanisms encompass heightened oxidative stress and inflammation, perturbed chondrocyte metabolism, and compromised autophagy. Furthermore, this review will explore potential interventions targeting mitochondrial metabolism as means to impede or decelerate the progression of OA. In summary, this review offers a comprehensive understanding of the involvement of mitochondrial metabolism in OA and underscores prospective intervention strategies.

Mini-encyclopedia of mitochondria-relevant nutraceuticals protecting health in primary and secondary care-clinically relevant 3PM innovation

Despite their subordination in humans, to a great extent, mitochondria maintain their independent status but tightly cooperate with the "host" on protecting the joint life quality and minimizing health risks. Under oxidative stress conditions, healthy mitochondria promptly increase mitophagy level to remove damaged "fellows" rejuvenating the mitochondrial population and sending fragments of mtDNA as SOS signals to all systems in the human body. As long as metabolic pathways are under systemic control and well-concerted together, adaptive mechanisms become triggered increasing systemic protection, activating antioxidant defense and repair machinery. Contextually, all attributes of mitochondrial patho-/physiology are instrumental for predictive medical approach and cost-effective treatments tailored to individualized patient profiles in primary (to protect vulnerable individuals again the health-to-disease transition) and secondary (to protect affected individuals again disease progression) care. Nutraceuticals are naturally occurring bioactive compounds demonstrating health-promoting, illness-preventing, and other health-related benefits. Keeping in mind health-promoting properties of nutraceuticals along with their great therapeutic potential and safety profile, there is a permanently growing demand on the application of mitochondria-relevant nutraceuticals. Application of nutraceuticals is beneficial only if meeting needs at individual level. Therefore, health risk assessment and creation of individualized patient profiles are of pivotal importance followed by adapted nutraceutical sets meeting individual needs. Based on the scientific evidence available for mitochondria-relevant nutraceuticals, this article presents examples of frequent medical conditions, which require protective measures targeted on mitochondria as a holistic approach following advanced concepts of predictive, preventive, and personalized medicine (PPPM/3PM) in primary and secondary care.

Mitochondrial quality control in human health and disease

Mitochondria, the most crucial energy-generating organelles in eukaryotic cells, play a pivotal role in regulating energy metabolism. However, their significance extends beyond this, as they are also indispensable in vital life processes such as cell proliferation, differentiation, immune responses, and redox balance. In response to various physiological signals or external stimuli, a sophisticated mitochondrial quality control (MQC) mechanism has evolved, encompassing key processes like mitochondrial biogenesis, mitochondrial dynamics, and mitophagy, which have garnered increasing attention from researchers to unveil their specific molecular mechanisms. In this review, we present a comprehensive summary of the primary mechanisms and functions of key regulators involved in major components of MQC. Furthermore, the critical physiological functions regulated by MQC and its diverse roles in the progression of various systemic diseases have been described in detail. We also discuss agonists or antagonists targeting MQC, aiming to explore potential therapeutic and research prospects by enhancing MQC to stabilize mitochondrial function.

Matrix stiffening promotes chondrocyte senescence and the osteoarthritis development through downregulating HDAC3

Extracellular matrix (ECM) stiffening is a typical characteristic of cartilage aging, which is a quintessential feature of knee osteoarthritis (KOA). However, little is known about how ECM stiffening affects chondrocytes and other molecules downstream. This study mimicked the physiological and pathological stiffness of human cartilage using polydimethylsiloxane (PDMS) substrates. It demonstrated that epigenetic Parkin regulation by histone deacetylase 3 (HDAC3) represents a new mechanosensitive mechanism by which the stiffness matrix affected chondrocyte physiology. We found that ECM stiffening accelerated cultured chondrocyte senescence in vitro, while the stiffness ECM downregulated HDAC3, prompting Parkin acetylation to activate excessive mitophagy and accelerating chondrocyte senescence and osteoarthritis (OA) in mice. Contrarily, intra-articular injection with an HDAC3-expressing adeno-associated virus restored the young phenotype of the aged chondrocytes stimulated by ECM stiffening and alleviated OA in mice. The findings indicated that changes in the mechanical ECM properties initiated pathogenic mechanotransduction signals, promoted the Parkin acetylation and hyperactivated mitophagy, and damaged chondrocyte health. These results may provide new insights into chondrocyte regulation by the mechanical properties of ECM, suggesting that the modification of the physical ECM properties may be a potential OA treatment strategy.

Potential application of traditional Chinese medicine in age-related macular degeneration-focusing on mitophagy

Retinal pigment epithelial cell and neuroretinal damage in age-related macular degeneration (AMD) can lead to serious visual impairments and blindness. Studies have shown that mitophagy, a highly specialized cellular degradation system, is implicated in the pathogenesis of AMD. Mitophagy selectively eliminates impaired or non-functioning mitochondria via several pathways, such as the phosphatase and tensin homolog-induced kinase 1/Parkin, BCL2-interacting protein 3 and NIP3-like protein X, FUN14 domain-containing 1, and AMP-activated protein kinase pathways. This has a major impact on the maintenance of mitochondrial homeostasis. Therefore, the regulation of mitophagy could be a promising therapeutic strategy for AMD. Traditional Chinese medicine (TCM) uses natural products that could potentially prevent and treat various diseases, such as AMD. This review aims to summarize recent findings on mitophagy regulation pathways and the latest progress in AMD treatment targeting mitophagy, emphasizing methods involving TCM.

Novel insights into the role of ubiquitination in osteoarthritis

Ubiquitination (Ub) and deubiquitination are crucial post-translational modifications (PTMs) that precisely regulate protein degradation. Under the catalysis of a cascade of E1-E2-E3 ubiquitin enzymes, ubiquitination extensively regulates protein degradation exerting direct impact on various cellular processes, while deubiquitination opposes the effect of ubiquitination and prevents proteins from degradation. Notably, such dynamic modifications have been widely investigated to be implicated in cell cycle, transcriptional regulation, apoptosis and so on. Therefore, dysregulation of ubiquitination and deubiquitination could lead to certain diseases through abnormal protein accumulation and clearance. Increasing researches have revealed that the dysregulation of catalytic regulators of ubiquitination and deubiquitination triggers imbalance of cartilage homeostasis that promotes osteoarthritis (OA) progression. Hence, it is now believed that targeting on Ub enzymes and deubiquitinating enzymes (DUBs) would provide potential therapeutic pathways. In the following sections, we will summarize the biological role of Ub enzymes and DUBs in the development and progression of OA by focusing on the updating researches, with the aim of deepening our understanding of the underlying molecular mechanism of OA pathogenesis concerning ubiquitination and deubiquitination, so as to explore novel potential therapeutic targets of OA treatment.

Network pharmacology mechanisms and experimental verification of licorice in the treatment of ulcerative colitis

ETHNOPHARMACOLOGICAL RELEVANCE

Licorice is widely used in the treatment of ulcerative colitis (UC) and has good antioxidant and anti-inflammatory effects, but its specific active ingredients and mechanisms of action are still unknown.

THE PURPOSE OF THE STUDY

To elucidate the specific molecular mechanisms of licorice in the treatment of UC and to experimentally verify its activity.

METHODS

Through network pharmacology, the active ingredients of licorice and the molecular targets of UC were identified. A traditional Chinese medicine (TCM)-components-target-disease network diagram was established, and the binding energies of the active ingredient and targets of licorice were verified by molecular docking. A BALB/c mice model of UC was established by treatment with 3% dextran sulfate sodium (DSS). The effect of licorice on colon tissue injury was histologically assessed. The expression of IL-6 and IL-17 in colon tissue was detected by immunohistochemistry (IHC). Transmission electron microscopy (TEM) was used to observe morphological changes in mitochondria in the colon. Caco2 cells were treated with lipopolysaccharide (LPS) for 24 h to establish the cell inflammatory damage model, and cells were exposed to different concentrations of drug-containing serum of Licorice (DCSL) for 24 h. In cells treated with the drug, the contents of oxidation markers were measured and ELISA was used to determine the levels of inflammatory factors in the cells. TEM was used to observe morphological changes in mitochondria. ZO-1 and occludin were detected by Western blotting. DCSL effects on autophagy were evaluated by treating cells with DCSL and autophagy inhibitor for 24 h after LPS injection. Small interfering ribonucleic acid (si-RNA) was used to silence Nrf2 gene expression in Caco2 cells to observe the effects of DCSL on autophagy through the Nrf2/PINK1 pathway. Nrf2, PINK1, HO-1, Parkin, P62, and LC3 were detected by Western blotting.

RESULTS

Ninety-one active ingredients and 339 action targets and 792 UC disease targets were identified, 99 of which were overlapping targets. Molecular docking was used to analyze the binding energies of liquiritin, liquiritigenin, glycyrrhizic acid, and glycyrrhetinic acid to the targets, with glycyrrhetinic acid having the strongest binding energy. In the UC mouse model, licorice improved colon histopathological changes, reduced levels of IL-6 and IL-17 and repaired mitochondrial damage. In the LPS-induced inflammation model of Caco2 cells, DCSL decreased MDA, IL-1β, Il-6, and TNF-α levels and increased those of Superoxide Dismutase (SOD), glutathione peroxidase (GSH-PX), and IL-10, and improved the morphological changes of mitochondria. Increased expression of Nrf2, PINK1, Parkin, HO-1, ZO-1, occludin, P62, and LC3 promoted autophagy and reduced inflammation levels.

CONCLUSION

Licorice improves UC, which may be related to the activation of the Nrf2/PINK1 signaling pathway that regulates autophagy.

Mechanisms of chondrocyte regulated cell death in osteoarthritis: Focus on ROS-triggered ferroptosis, parthanatos, and oxeiptosis

Osteoarthritis (OA) is a common chronic inflammatory degenerative disease. Since chondrocytes are the only type of cells in cartilage, their survival is critical for maintaining cartilage morphology. This review offers a comprehensive analysis of how reactive oxygen species (ROS), including superoxide anions, hydrogen peroxide, hydroxyl radicals, nitric oxide, and their derivatives, affect cartilage homeostasis and trigger several novel modes of regulated cell death, including ferroptosis, parthanatos, and oxeiptosis, which may play roles in chondrocyte death and OA development. Moreover, we discuss potential therapeutic strategies to alleviate OA by scavenging ROS and provide new insight into the research and treatment of the role of regulated cell death in OA.

Curcumin regulates autophagy through SIRT3-SOD2-ROS signaling pathway to improve quadriceps femoris muscle atrophy in KOA rat model

Knee osteoarthritis (KOA) usually leads to quadriceps femoris atrophy, which in turn can further aggravate the progression of KOA. Curcumin (CUR) has anti-inflammatory and antioxidant effects and has been shown to be a protective agent for skeletal muscle. CUR has been shown to have a protective effect on skeletal muscle. However, there are no studies related to whether CUR improves KOA-induced quadriceps femoris muscle atrophy. We established a model of KOA in rats. Rats in the experimental group were fed CUR for 5 weeks. Changes in autophagy levels, reactive oxygen species (ROS) levels, and changes in the expression of the Sirutin3 (SIRT3)-superoxide dismutase 2 (SOD2) pathway were detected in the quadriceps femoris muscle of rats. KOA led to quadriceps femoris muscle atrophy, in which autophagy was induced and ROS levels were increased. CUR increased SIRT3 expression, decreased SOD2 acetylation and ROS levels, inhibited the over-activation of autophagy, thereby alleviating quadriceps femoris muscle atrophy and improving KOA. CUR has a protective effect against quadriceps femoris muscle atrophy, and KOA is alleviated after improvement of quadriceps femoris muscle atrophy, with the possible mechanism being the reduction of ROS-induced autophagy via the SIRT3-SOD2 pathway.

Efficacy and Safety of Two Chondroprotective Supplements in Patients With Knee Osteoarthritis: A Randomized, Single-Blind, Pilot Study

Background: Hyaluronic acid (HA), glucosamine (Glc), and chondroitin sulfate (CS) are key ingredients commonly incorporated into dietary chondroprotective supplements for the management of osteoarthritis (OA). Despite their widespread use, there is a paucity of published data regarding their efficacy and safety, necessitating rigorous investigation in clinical settings. To address this knowledge gap, we conducted a randomized, single-blind pilot study to evaluate the effects of two commercially available multi-ingredient supplements on patients with mild-to-moderate knee OA. Methods: A total of 51 patients diagnosed with mild-to-moderate knee OA were enrolled in a four-week randomized study and allocated equally (1:1:1 ratio) into three groups: a control group (n = 17) that received no treatment, an HA group (n = 17) given Syalox® 300 Plus (1 tablet/day) containing HA (300 mg) and Boswellia serrata extract (100 mg), and a Glc + CS group (n = 17) given Cartijoint® Forte (1 tablet/day) containing Glc (415 mg), CS (400 mg), and curcuminoids from rhizomes of Curcuma longa L (50 mg).Physicians conducting evaluations were blinded to group assignments, whereas patients were not. All participants underwent assessments of pain relief, functional capacity improvement, and serum adropin levels, an emerging biomarker of knee OA, at baseline and after the four-week intervention period. Results: Both the HA and the Glc + CS groups exhibited improvements at the end of the study relative to baseline, with statistically significant differences (p < 0.05) observed in pain at rest, pain during movement, range of motion, and the overall Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores, including its pain, stiffness, and physical function subscales. Notably, the HA group outperformed the Glc + CS group in the alleviation of pain at rest, pain during movement, and on the WOMAC pain subscale, with all differences being statistically significant (p < 0.05). Additionally, both groups showed a significant elevation in serum adropin levels from baseline (p < 0.05), with the HA group experiencing a more substantial increase when compared to the Glc + CS group (p < 0.05). Both supplements showed a limited number of treatment-emergent adverse events. Conclusion: Oral supplementation with either HA or Glc + CS demonstrated potential benefits for managing symptoms of mild-to-moderate knee OA. Notably, HA supplementation was associated with greater improvements in pain relief and higher elevations in serum adropin levels compared to Glc + CS supplementation. However, larger-scale and longer-term studies are necessary to further evaluate the safety and efficacy of these dietary supplements within the clinical management arsenal for knee OA.

Sirtuin 1 in osteoarthritis: Perspectives on regulating glucose metabolism

Osteoarthritis (OA) is a degenerative disease characterised by articular cartilage destruction, and its complex aetiology contributes to suboptimal clinical treatment outcomes. A close association exists between glucose metabolism dysregulation and OA pathogenesis. Owing to the unique environment of low oxygen and glucose concentrations, chondrocytes rely heavily on their glycolytic capacity, exhibiting distinct spatiotemporal differences. However, under pathological stimulation, chondrocytes undergo excessive glycolytic activity while mitochondrial respiration and other branches of glucose metabolism are compromised. This metabolic change induces cartilage degeneration by reprogramming the inflammatory responses. Sirtuins, a highly conserved family of nicotinamide adenine dinucleotide (NAD+)-dependent deacetylases, regulate glucose metabolism in response to energy fluctuations in different cellular compartments，alleviating metabolic stress. SIRT1, the most extensively studied sirtuin, participates in maintaining glucose homeostasis in almost all key metabolic tissues. While actively contributing to the OA progression and displaying diverse biological effects in cartilage protection, SIRT1's role in regulating glucose metabolism in chondrocytes has not received sufficient attention. This review focuses on discussing the beneficial role of SIRT1 in OA progression from a metabolic regulation perspective based on elucidating the primary characteristics of chondrocyte glucose metabolism. We also summarise the potential mechanisms and therapeutic strategies targeting SIRT1 in chondrocytes to guide clinical practice and explore novel therapeutic directions.

WITHDRAWN: The dysregulated autophagy in osteoarthritis: Revisiting molecular profile

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α-Solanine attenuates chondrocyte pyroptosis to improve osteoarthritis via suppressing NF-κB pathway

α-Solanine has been shown to exhibit anti-inflammatory and anti-tumour properties; however, its efficacy in treating osteoarthritis (OA) remains ambiguous. The study aimed to evaluate the therapeutic effects of α-solanine on OA development in a mouse OA model. The OA mice were subjected to varying concentrations of α-solanine, and various assessments were implemented to assess OA progression. We found that α-solanine significantly reduced osteophyte formation, subchondral sclerosis and OARSI score. And it decreased proteoglycan loss and calcification in articular cartilage. Specifically, α-solanine inhibited extracellular matrix degradation by downregulating collagen 10, matrix metalloproteinase 3 and 13, and upregulating collagen 2. Importantly, α-solanine reversed chondrocyte pyroptosis phenotype in articular cartilage of OA mice by inhibiting the elevated expressions of Caspase-1, Gsdmd and IL-1β, while also mitigating aberrant angiogenesis and sensory innervation in subchondral bone. Mechanistically, α-solanine notably hindered the early stages of OA progression by reducing I-κB phosphorylation and nuclear translocation of p65, thereby inactivating NF-κB signalling. Our findings demonstrate the capability of α-solanine to disrupt chondrocyte pyroptosis and sensory innervation, thereby improving osteoarthritic pathological progress by inhibiting NF-κB signalling. These results suggest that α-solanine could serve as a promising therapeutic agent for OA treatment.

A Lightweight Browser-Based Tool for Collaborative and Blinded Image Analysis

Collaborative manual image analysis by multiple experts in different locations is an essential workflow in biomedical science. However, sharing the images and writing down results by hand or merging results from separate spreadsheets can be error-prone. Moreover, blinding and anonymization are essential to address subjectivity and bias. Here, we propose a new workflow for collaborative image analysis using a lightweight online tool named Tyche. The new workflow allows experts to access images via temporarily valid URLs and analyze them blind in a random order inside a web browser with the means to store the results in the same window. The results are then immediately computed and visible to the project master. The new workflow could be used for multi-center studies, inter- and intraobserver studies, and score validations.

Moxibustion ameliorates osteoarthritis by regulating gut microbiota via impacting cAMP-related signaling pathway

BACKGROUND

Osteoarthritis (OA) is a prevalent progressive disorder. Moxibustion has found widespread use in clinical practice for OA, while its underlying mechanism remains elusive.

OBJECTIVE

To investigate whether moxibustion can ameliorate OA by influencing the metabolic processes in OA and to elucidate the specific metabolic mechanisms involved.

METHODS

C57BL/6J WT mice were randomly assigned to one of three groups: the SHAM group, the ACLT group, and the ACLT+M group. In the ACLT+M group, mice underwent moxibustion treatment at acupoints Shenshu (BL23) and Zusanli (ST36) for a continuous period of 28 days, with each session lasting 20 min. We conducted a comprehensive analysis to assess the impact of moxibustion on OA, focusing on pathological changes, intestinal flora composition, and serum metabolites.

RESULTS

Moxibustion treatment effectively mitigated OA-related pathological changes. Specifically, moxibustion treatment resulted in the amelioration of articular cartilage damage, synovial inflammation, subchondral bone sclerosis when compared to the ACLT group. Moreover, 16S rDNA sequencing analysis revealed that moxibustion treatment positively influenced the composition of the flora, making it more similar to that of the SHAM group. Notably, moxibustion treatment led to a reduction in the abundance of Ruminococcus and Proteobacteria in the intestine. In addition, non-targeted metabolomics analysis identified 254 significantly different metabolites between the groups. Based on KEGG pathway analysis and the observed impact of moxibustion on OA-related inflammation, moxibustion therapy is closely associated with the cAMP-related signaling pathway.

CONCLUSION

Moxibustion can relieve OA by regulating intestinal flora and via impacting cAMP-related signaling pathway.

Targeting ROS in osteoclasts within the OA environment: A novel therapeutic strategy for osteoarthritis management

This study investigated the therapeutic potential of a manganese dioxide-polymer dot (MnO2-PD)-incorporated hydrogel, designated as M-PD hydrogel, for modulating reactive oxygen species (ROS) within the osteoarthritis (OA) environment. Our research highlights the ability of the hydrogel to scavenge ROS, thereby influencing the differentiation of osteoclasts and protecting chondrocytes, offering a novel approach to osteoarthritis (OA) management. Our results indicated that the M-PD hydrogel increased electrical resistance and fluorescence recovery in the presence of osteoclasts, correlating with decreased ROS levels and suppressed expression of osteoclast differentiation markers. Coculture experiments revealed the protective effects of the hydrogel on chondrocytes by reducing the expression of matrix-degrading enzymes. In vivo application in burr holes and/or OA-induced mice revealed a significant reduction in osteoclast formation and cartilage destruction, suggesting the dual therapeutic action of the hydrogel in altering the joint microenvironment. These findings highlight the potential of targeting ROS in osteoclasts as a comprehensive therapeutic approach, offering not only symptomatic relief but also targeting the underlying mechanisms of disease progression in OA.

Neuron-targeted overexpression of caveolin-1 alleviates diabetes-associated cognitive dysfunction via regulating mitochondrial fission-mitophagy axis

BACKGROUND

Type 2 diabetes mellitus (T2DM) induced diabetes-associated cognitive dysfunction (DACD) that seriously affects the self-management of T2DM patients, is currently one of the most severe T2DM-associated complications, but the mechanistic basis remains unclear. Mitochondria are highly dynamic organelles, whose function refers to a broad spectrum of features such as mitochondrial dynamics, mitophagy and so on. Mitochondrial abnormalities have emerged as key determinants for cognitive function, the relationship between DACD and mitochondria is not well understood.

METHODS

Here, we explored the underlying mechanism of mitochondrial dysfunction of T2DM mice and HT22 cells treated with high glucose/palmitic acid (HG/Pal) focusing on the mitochondrial fission-mitophagy axis with drug injection, western blotting, Immunofluorescence, and electron microscopy. We further explored the potential role of caveolin-1 (cav-1) in T2DM induced mitochondrial dysfunction and synaptic alteration through viral transduction.

RESULTS

As previously reported, T2DM condition significantly prompted hippocampal mitochondrial fission, whereas mitophagy was blocked rather than increasing, which was accompanied by dysfunctional mitochondria and impaired neuronal function. By contrast, Mdivi-1 (mitochondrial division inhibitor) and urolithin A (mitophagy activator) ameliorated mitochondrial and neuronal function and thereafter lead to cognitive improvement by inhibiting excessive mitochondrial fission and giving rise to mitophagy, respectively. We have previously shown that cav-1 can significantly improve DACD by inhibiting ferroptosis. Here, we further demonstrated that cav-1 could not only inhibit mitochondrial fission via the interaction with GSK3β to modulate Drp1 pathway, but also rescue mitophagy through interacting with AMPK to activate PINK1/Parkin and ULK1-dependent signlings.

CONCLUSIONS

Overall, our data for the first time point to a mitochondrial fission-mitophagy axis as a driver of neuronal dysfunction in a phenotype that was exaggerated by T2DM, and the protective role of cav-1 in DACD. Graphic Summary Illustration. In T2DM, excessive mitochondrial fission and impaired mitophagy conspire to an altered mitochondrial morphology and mitochondrial dysfunction, with a consequent neuronal damage, overall suggesting an unbalanced mitochondrial fission-mitophagy axis. Upon cav-1 overexpression, GSK3β and AMPK are phosphorylated respectively to activate Drp1 and mitophagy-related pathways (PINK1 and ULKI), ultimately inhibits mitochondrial fission and enhances mitophagy. In the meantime, the mitochondrial morphology and neuronal function are rescued, indicating the protective role of cav-1 on mitochondrial fission-mitophagy axis. Video Abstract.

New insight of the pathogenesis in osteoarthritis: the intricate interplay of ferroptosis and autophagy mediated by mitophagy/chaperone-mediated autophagy

Ferroptosis, characterized by iron accumulation and lipid peroxidation, is a form of iron-driven cell death. Mitophagy is a type of selective autophagy, where degradation of damaged mitochondria is the key mechanism for maintaining mitochondrial homeostasis. Additionally, Chaperone-mediated autophagy (CMA) is a biological process that transports individual cytoplasmic proteins to lysosomes for degradation through companion molecules such as heat shock proteins. Research has demonstrated the involvement of ferroptosis, mitophagy, and CMA in the pathological progression of Osteoarthritis (OA). Furthermore, research has indicated a significant correlation between alterations in the expression of reactive oxygen species (ROS), adenosine monophosphate (AMP)-activated protein kinase (AMPK), and hypoxia-inducible factors (HIFs) and the occurrence of OA, particularly in relation to ferroptosis and mitophagy. In light of these findings, our study aims to assess the regulatory functions of ferroptosis and mitophagy/CMA in the pathogenesis of OA. Additionally, we propose a mechanism of crosstalk between ferroptosis and mitophagy, while also examining potential pharmacological interventions for targeted therapy in OA. Ultimately, our research endeavors to offer novel insights and directions for the prevention and treatment of OA.