The role of SIRT3-mediated mitochondrial homeostasis in osteoarthritis

Mitochondrial quality control dysfunction in osteoarthritis: Mechanisms, therapeutic strategies & future prospects

Osteoarthritis (OA) is a prevalent chronic joint disease characterized by articular cartilage degeneration, pain, and disability. Emerging evidence indicates that mitochondrial quality control dysfunction contributes to OA pathogenesis. Mitochondria are essential organelles to generate cellular energy via oxidative phosphorylation and regulate vital processes. Impaired mitochondria can negatively impact cellular metabolism and result in the generation of harmful reactive oxygen species (ROS). Dysfunction in mitochondrial quality control mechanisms has been increasingly linked to OA onset and progression. This review summarizes current knowledge on the role of mitochondrial quality control disruption in OA, highlighting disturbed mitochondrial dynamics, impaired mitochondrial biogenesis, antioxidant defenses and mitophagy. The review also discusses potential therapeutic strategies targeting mitochondrial Quality Control in OA, offering future perspectives on advancing OA therapeutic strategies.

Bu zhong Yiqi Decoction ameliorates mild cognitive impairment by improving mitochondrial oxidative stress damage via the SIRT3/MnSOD/OGG1 pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Bu-Zhong-Yi-Qi Decoction(BZYQD) is a traditional formula commonly used in China, known for its effects in tonifying Qi and raising Yang. It can relieve symptoms of cognitive impairment such as forgetfulness and lack of concentration caused by qi deficiency, which is common in aging and debilitating. However, much of the current research on BZYQD has been focused on its impact on the digestive system, leaving its molecular mechanisms in improving cognitive function largely unexplored.

AIM OF THE STUDY

Cognitive decline in the aging central nervous system is intrinsically linked to oxidative damage. This study aims to investigate the therapeutic mechanism of BZYQD in treating mild cognitive impairment caused by qi deficiency, particularly through repair of mitochondrial oxidative damage.

MATERIALS AND METHODS

A rat model of mild cognitive impairment (MCI) was established by administering reserpine subcutaneously for two weeks, followed by a two-week treatment with BZYQD/GBE. In vitro experiments were conducted to assess the effects of BZYQD on neuronal cells using a H2O2-induced oxidative damage model in PC12 cells. The open field test and the Morris water maze test evaluated the cognitive and learning memory abilities of the rats. HE staining and TEM were employed to observe morphological changes in the hippocampus and its mitochondria. Mitochondrial activity, ATP levels, and cellular viability were measured using assay kits. Protein expression in the SIRT3/MnSOD/OGG1 pathway was analyzed in tissues and cells through western blotting. Levels of 8-OH-dG in mitochondria extracted from tissues and cells were quantified using ELISA. Mitochondrial morphology in PC12 cells was visualized using Mito Red, and mitochondrial membrane potential was assessed using the JC-1 kit.

RESULTS

BZYQD treatment significantly improved cognitive decline caused by reserpine in rats, as well as enhanced mitochondrial morphology and function in the hippocampus. Our findings indicate that BZYQD mitigates mtDNA oxidative damage in rats by modulating the SIRT3/MnSOD/OGG1 pathway. In PC12 cells, BZYQD reduced oxidative damage to mitochondria and mtDNA in H2O2-induced conditions and was associated with changes in the SIRT3/MnSOD/OGG1 pathway.

CONCLUSION

BZYQD effectively counteracts reserpine-induced mild cognitive impairment and ameliorates mitochondrial oxidative stress damage through the SIRT3/MnSOD/OGG1 pathway.

The Changes of Mitochondria during Aging and Regeneration

Aging and regeneration are opposite cellular processes. Aging refers to progressive dysfunction in most cells and tissues, and regeneration refers to the replacement of damaged or dysfunctional cells or tissues with existing adult or somatic stem cells. Various studies have shown that aging is accompanied by decreased regenerative abilities, indicating a link between them. The performance of any cellular process needs to be supported by the energy that is majorly produced by mitochondria. Thus, mitochondria may be a link between aging and regeneration. It should be interesting to discuss how mitochondria behave during aging and regeneration. The changes of mitochondria in aging and regeneration discussed in this review can provide a timely and necessary study of the causal roles of mitochondrial homeostasis in longevity and health.

Advances in SIRT3 involvement in regulating autophagy-related mechanisms

The silencing regulatory factor 2-like protein 3 (SIRT3) is a nicotinamide adenine dinucleotide (NAD+) dependent deacetylase located primarily in the mitochondria. This protein plays an important role in oxidative stress, energy metabolism, and autophagy in multicellular organisms. Autophagy (macroautophagy) is primarily a cytoprotective mechanism necessary for intracellular homeostasis and the synthesis, degradation, and recycling of cellular products. Autophagy can influence the progression of several neural, cardiac, hepatic, and renal diseases and can also contribute to the development of fibrosis, diabetes, and many types of cancer. Recent studies have shown that SIRT3 has an important role in regulating autophagy. Therefore in this study, we aimed to perform a literature review to summarize the role of SIRT3 in the regulation of cellular autophagy. The findings of this study could be used to identify new drug targets for SIRT3-related diseases. Methods: A comprehensive literature review of the mechanism involved behind SIRT3 and autophagy-related diseases was performed. Relevant literature published in Pubmed and Web of Science up to July 2023 was identified using the keywords "silencing regulatory factor 2-like protein 3", "SIRT3" and "autophagy".

Protective effects of baicalin against phenylarsine oxide-induced cytotoxicity in human skin keratinocytes

Phenylarsine oxide (PAO) is a known environmental pollutant and skin keratinocytes are most seriously affected. Baicalin (BCN) was reported to have antioxidant and anti-inflammatory effects, but its protective effect against PAO toxicity is unknown. This study aimed at exploring whether baicalin can reverse the toxicity of human epidermal keratinocytes that are subjected to PAO exposure and underlying mechanisms. In silico analysis from a publicly accessible HaCaT cell transcriptome dataset exposed to chronic Arsenic showed significant differential expression of several genes, including the genes related to DNA replication. Later, we performed in vitro experiments, in which HaCaT cells were exposed to PAO (500 nM) in the existence of BCN (10-50 µM). Treatment of PAO alone induces the JNK, p38 and caspase-3 activation, which were engaged in the apoptosis induction, while the activity of AKT was significantly inhibited, which was engaged in the suppression of apoptosis. PAO suppressed SIRT3 expression and induced intracellular reactive oxygen species (ROS), causing a marked reduce in cell viability and apoptosis. However, BCN treatment restored the PAO-induced suppression of SIRT3 and AKT expression, reduced intracellular ROS generation, and markedly suppressed both caspase-3 activation and apoptosis induction. However, the protective effect of BCN was significantly attenuated after pretreatment with nicotinamide, an inhibitor of SIRT3. These findings indicate that BCN protects against cell death induced by PAO via inhibiting excessive intracellular ROS generation via restoring SIRT3 activity and reactivating downstream AKT pathway. In this study, we firstly shown that BCN is an efficient drug to prevent PAO-induced skin cytotoxicity, and these findings need to be confirmed by in vivo and clinical investigations.

Mitochondria-Related Gene MAOB is a Key Biomarker of Osteoarthritis and Inhibition of Its Expression Reduces LPS-induced Chondrocyte Damage

The mitochondria are an important organelle in cells responsible for producing energy, and its abnormal function is closely related to the occurrence and development of osteoarthritis. Finding key genes associated with mitochondrial dysfunction in osteoarthritis can provide new ideas for the study of its pathogenesis. Firstly, 371 differential expressed genes (DEGs) were obtained through bioinformatics analysis of the GSE12021 and GSE55235 datasets in the GEO database, and 24 mitochondria-related DEGs (Mito-DEGs) were obtained by crossing differential genes with mitochondrial related genes. Next, KEGG and GO analysis of Mito-DEGs showed that upregulated Mito-DEGs were mainly enriched in small molecule catabolic process and tryptophan metabolism, while downregulated Mito-DEGs were mainly enriched in acetyl-CoA metabolic process and fatty acid biosynthesis. Furthermore, the key genes ME2 and MAOB were obtained through protein-protein interaction network analysis and lasso cox analysis of the 24 Mito-DEGs. In addition, the comparison results of immune cell scores showed differences between T cells CD4 memory resting, T cells regulatory (Tregs), Mast cells resting, and Mast cells activated in the OA group and the control group. More importantly, the potential regulatory mechanisms of key genes were studied through GSEA analysis and their correlation with immune infiltrating cells, immune checkpoints, m6A, and ferroptosis. Finally, in LPS-induced C28/I2 cells, silencing MAOB reduced inflammation injury and inhibited mitochondrial damage. Our research findings suggest that MAOB may hold potential as a target for the diagnosis and treatment of osteoarthritis.

Acupotomy alleviates knee osteoarthritis in rabbit by regulating chondrocyte mitophagy Pink1-Parkin pathway

OBJECTIVE

To investigate the effect of acupotomy, on mitophagy and the Pink1-Parkin pathway in chondrocytes from rabbits with knee osteoarthritis (KOA).

METHODS

A KOA model was established via the modified Videman method. Rabbits were randomly divided into a control group (CON), KOA group and KOA + acupotomy group (Acu). Rabbits in the acupotomy group were subjected to acupotomy for 4 weeks after model establishment. The behavior of the rabbits before and after intervention was recorded. Cartilage degeneration was evaluated by optical microscopy and fluorescence microscopy. The level of mitophagy was evaluated by transmission electron microscopy, immunofluorescence and enzyme-linked immunosorbent assay (ELISA). The expression of phosphatase and tensin homolog (PTEN)-induced kinase 1 (Pink1)-Parkin mitophagy pathway components was evaluated by immunofluorescence, Western blotting and real-time polymerase chain reaction.

RESULTS

In rabbits with KOA, joint pain, mobility disorders and cartilage degeneration were observed, the Mankin score was increased, collagen type Ⅱ (Col-Ⅱ) expression was significantly decreased, mitophagy was inhibited, mitochondrial function was impaired, and factors associated with the Pink1-Parkin pathway were inhibited. Acupotomy regulated the expression of Pink1-Parkin pathway-related proteins, the mitophagy-related protein microtubule-associated protein-1 light chain-3, the translocase of the outer membrane, and the inner mitochondrial membrane 23; increased the colocalization of mitochondria and autophagosomes; promoted the removal of damaged mitochondria; restored mitochondrial adenosine-triphosphate (ATP) production; and alleviated cartilage degeneration in rabbits with KOA.

CONCLUSIONS

Acupotomy played a role in alleviating KOA in rabbits by activating mitophagy in chondrocytes via the regulation of proteins that are related to the Pink1-Parkin pathway.

Intrauterine hyperglycemia induces SIRT3-mediated mitochondrial dysfunction: the fetal origin pathogenesis of precocious osteoarthritis

OBJECTIVE

Diabetes and other metabolic and inflammatory comorbidities are highly associated with osteoarthritis (OA). However, whether early-life hyperglycemia exposure affects susceptibility to long-term OA is still unknown. The purpose of this study was to explore the fetal origins of OA and provide insights into early-life safeguarding for individual health.

METHOD

This study utilized streptozotocin to induce intrauterine hyperglycemia and performed destabilization of the medial meniscus surgery on the knee joints of the offspring mice to induce accelerated OA. Cartilage degeneration-related markers, as well as the expression levels of mitochondrial respiratory chain complexes and mitophagy genes in the adult offspring mice, were investigated. In vitro, mitochondrial function and mitophagy of chondrocyte C28/I2 cells stimulated under high glucose conditions were also evaluated. The methylation levels of the sirt3 gene promoter region in the articular cartilage of intrauterine hyperglycemia-exposed offspring mice were further analyzed.

RESULTS

In this study, we found that the intrauterine hyperglycemic environment could lead to an increase in individual susceptibility to OA in late adulthood, mainly due to persistently low levels of Sirt3 expression. Downregulation of Sirt3 causes impaired mitophagy in chondrocytes and abnormal mitochondrial respiratory function due to a failure to clear aged and damaged mitochondria in a timely manner. Overexpressing Sirt3 at the cellular level or using Sirt3 agonists like Honokiol in mouse models can partially rescue mitophagy disorders caused by the hyperglycemic environment and thus alleviate the progression of OA.

CONCLUSION

Our study revealed a significantly increased susceptibility to OA in the gestational diabetes mellitus offspring, which is partly attributed to exposure to adverse factors in utero and ultimately to the onset of disease via epigenetic modulation.

SIRT1 restores mitochondrial structure and function in rats by activating SIRT3 after cerebral ischemia/reperfusion injury

Mitochondrial dysfunction contributes to cerebral ischemia-reperfusion (CI/R) injury, which can be ameliorated by Sirtuin-3 (SIRT3). Under stress conditions, the SIRT3-promoted mitochondrial functional recovery depends on both its activity and expression. However, the approach to enhance SIRT3 activity after CI/R injury remains unelucidated. In this study, Sprague-Dawley (SD) rats were intracranially injected with either adeno-associated viral Sirtuin-1 (AAV-SIRT1) or AAV-sh_SIRT1 before undergoing transient middle cerebral artery occlusion (tMCAO). Primary cortical neurons were cultured and transfected with lentiviral SIRT1 (LV-SIRT1) and LV-sh_SIRT1 respectively before oxygen-glucose deprivation/reoxygenation (OGD/R). Afterwards, rats and neurons were respectively treated with a selective SIRT3 inhibitor, 3-(1H-1,2,3-triazol-4-yl) pyridine (3-TYP). The expression, function, and related mechanism of SIRT1 were investigated by Western Blot, flow cytometry, immunofluorescence staining, etc. After CI/R injury, SIRT1 expression decreased in vivo and in vitro. The simulation and immune-analyses reported strong interaction between SIRT1 and SIRT3 in the cerebral mitochondria before and after CI/R. SIRT1 overexpression enhanced SIRT3 activity by increasing the deacetylation of SIRT3, which ameliorated CI/R-induced cerebral infarction, neuronal apoptosis, oxidative stress, neurological and motor dysfunction, and mitochondrial respiratory chain dysfunction, promoted mitochondrial biogenesis, and retained mitochondrial integrity and mitochondrial morphology. Meanwhile, SIRT1 overexpression alleviated OGD/R-induced neuronal death and mitochondrial bioenergetic deficits. These effects were reversed by AAV-sh_SIRT1 and the neuroprotective effects of SIRT1 were partially offset by 3-TYP. These results suggest that SIRT1 restores the structure and function of mitochondria by activating SIRT3, offering neuroprotection against CI/R injury, which signifies a potential approach for the clinical management of cerebral ischemia.

TGF-β3 mediates mitochondrial dynamics through the p-Smad3/AMPK pathway

It is well recognized that mitochondrial dynamics plays a vital role in cartilage physiology. Any perturbation in mitochondrial dynamics could cause disorders in cartilage metabolism and even lead to the occurrence of cartilage diseases such as osteoarthritis (OA). TGF-β3, as an important growth factor that appears in the joints of OA disease, shows its great potential in chondrocyte growth and metabolism. Nevertheless, the role of TGF-β3 on mitochondrial dynamics is still not well understood. Here we aimed to investigate the effect of TGF-β3 on mitochondrial dynamics of chondrocytes and reveal its underlying bio-mechanism. By using transmission electron microscopy (TEM) for the number and morphology of mitochondria, western blotting for the protein expressions, immunofluorescence for the cytoplasmic distributions of proteins, and RNA sequencing for the transcriptome changes related to mitochondrial dynamics. We found that TGF-β3 could increase the number of mitochondria in chondrocytes. TGF-β3-enhanced mitochondrial number was via promoting the mitochondrial fission. The mitochondrial fission induced by TGF-β3 was mediated by AMPK signaling. TGF-β3 activated canonical p-Smad3 signaling and resultantly mediated AMPK-induced mitochondrial fission. Taken together, these results elucidate an understanding of the role of TGF-β3 on mitochondrial dynamics in chondrocytes and provide potential cues for therapeutic strategies in cartilage injury and OA disease in terms of energy metabolism.

MSRB2 Ameliorates H2O2-induced Chondrocyte Oxidative Stress and Suppresses Apoptosis in Osteoarthritis

BACKGROUND

Chondrocyte oxidative stress and apoptosis are critical factors contributing to the pathogenesis of osteoarthritis (OA). Methionine sulfoxide reductase B2 (MSRB2) is a mitochondrial protein that protects cells from oxidative stress and is involved in apoptosis. This study aimed to investigated the expression of MSRB2 in articular cartilage tissues and elucidated its effect on H2O2-stimulated chondrocytes.

METHODS

Human chondrocytes were cultured in Dulbecco's modified Eagle's medium (DMEM)/F12. MSRB2 overexpression in chondrocytes was achieved by transfecting with an MSRB2 overexpression plasmid. Western blot, quantitative RT-PCR, Immunofluorescence staining, and TUNEL assay were employed in this study.

RESULTS

MSRB2 expression was found to be reduced in OA patients. Furthermore, overexpression of MSRB2 in H2O2-induced chondrocytes mitigated apoptosis and enhanced cell viability. Elevated MSRB2 expression diminished chondrocyte ROS contents, decreased cytochrome C (Cyc) in the cytoplasm, and regulated mitochondrial membrane potential to maintain mitochondrial homeostasis. Interestingly, knockdown of charged multivesicular body protein 5 (CHMP5) led to a decreased inMSRB2 expression in chondrocytes. Additionally, protein levels of CHMP5 and MSRB2 were reduced in H2O2-stimulated chondrocytes, and silencing CHMP5 reduced MSRB2 expression. Knockdown of CHMP5 increased cleaved caspase-3 expression in H2O2-induced chondrocytes and elevated TUNEL-positive chondrocytes.

CONCLUSION

MSRB2 decreased in OA, and overexpression of MSRB2 alleviated oxidative stress and apoptosis of chondrocyte.

Interplay between lipid dysregulation and ferroptosis in chondrocytes and the targeted therapy effect of metformin on osteoarthritis

INTRODUCTION

Osteoarthritis (OA) is a devastating whole-joint disease affecting a large population worldwide; the role of lipid dysregulation in OA and mechanisms underlying targeted therapy effect of lipid-lowering metformin on OA remains poorly defined.

OBJECTIVES

To investigate the effects of lipid dysregulation on OA progression and to explore lipid dysregulation-targeting OA treatment of metformin.

METHODS

RNA-Seq data, biochemical, and histochemical assays in human and murine OA cartilage as well as primary chondrocytes were utilized to determine lipid dysregulation. Effects of metformin, a potent lipid-lowering medication, on ACSL4 expression and chondrocyte metabolism were determined. Further molecular experiments, including RT-qPCR, western blotting, flow cytometry, and immunofluorescence staining, were performed to investigate underlying mechanisms. Mice with intra-articular injection of metformin were utilized to determine the effects on ACLT-induced OA progression.

RESULTS

ACSL4 and 4-HNE expressions were elevated in human and ACLT-induced mouse OA cartilage and IL-1β-treated chondrocytes (P < 0.05). Ferrostatin-1 largely rescued IL-1β-induced MDA, lipid peroxidation, and ferroptotic mitochondrial morphology (P < 0.05). Metformin decreased the levels of OA-related genes (P < 0.05) and increased the levels of p-AMPK and p-ACC in IL-1β-treated chondrocytes. Intra-articular injection of metformin alleviated ACLT-induced OA lesions in mice, and reverted the percentage of chondrocytes positive for MMP13, Col2a1, ACSL4 and 4-HNE in ACLT mice (P < 0.05). Ferroptotic chondrocytes promoted the recruitment and chemotaxis of RAW264.7 cells via CCL2, which was blocked by metformin in vitro (P < 0.05).

CONCLUSION

We establish a critical role of polyunsaturated fatty acids metabolic process in OA cartilage degradation and define metformin as a potential OA treatment. Metformin reshapes lipid availability and ameliorates chondrocyte ferroptosis sensitivity via the AMPK/ACC pathway. In the future, gene-edited animals and extensive omics technologies will be utilized to reveal detailed lipids' involvement in cartilage lesions.

The protective mechanism of SIRT3 and potential therapy in acute kidney injury

Acute kidney injury (AKI) is a complex clinical syndrome with a poor short-term prognosis, which increases the risk of the development of chronic kidney diseases and end-stage kidney disease. However, the underlying mechanism of AKI remains to be fully elucidated, and effective prevention and therapeutic strategies are still lacking. Given the enormous energy requirements for filtration and absorption, the kidneys are rich in mitochondria, which are unsurprisingly involved in the onset or progression of AKI. Accumulating evidence has recently documented that Sirtuin 3 (SIRT3), one of the most prominent deacetylases highly expressed in the mitochondria, exerts a protective effect on AKI. SIRT3 protects against AKI by regulating energy metabolism, inhibiting oxidative stress, suppressing inflammation, ameliorating apoptosis, inhibiting early-stage fibrosis and maintaining mitochondrial homeostasis. Besides, a number of SIRT3 activators have exhibited renoprotective properties both in animal models and in vitro experiments, but have not yet been applied to clinical practice, indicating a promising therapeutic approach. In this review, we unravel and summarize the recent advances in SIRT3 research and the potential therapy of SIRT3 activators in AKI.

SIRT3 alleviates high glucose-induced chondrocyte injury through the promotion of autophagy and suppression of apoptosis in osteoarthritis progression

A growing amount of epidemiological evidence proposes diabetes mellitus (DM) to be an independent risk factor for osteoarthritis (OA). Sirtuin 3 (SIRT3), which is mainly located in mitochondria, belongs to the family of nicotinamide adenine dinucleotide (NAD+)-dependent protein deacetylases and is involved in the physiological and pathological processes of cell regulation. The aim of this study was to investigate the effects of SIRT3 on diabetic OA and underlying mechanisms in the prevention of type 2 DM (T2DM)-induced articular cartilage damage. High-fat and high-sugar diets combined with streptozotocin (STZ) injection were used for establishing an experimental T2DM rat model. The destabilization of medial meniscus (DMM) surgery was applied to induce the rat OA model. Primary rat chondrocytes were cultivated with a concentration of gradient glucose. Treatment with intra-articular injection of SIRT3 overexpression lentivirus was achieved in vivo, and intervention with SIRT3 knockdown was performed using siRNA transfection in vitro. High glucose content was found to activate inflammatory response, facilitate apoptosis, downregulate autophagy, and exacerbate mitochondrial dysfunction in a dose-dependent manner in rat chondrocytes, which can be deteriorated by SIRT3 knockdown. In addition, articular cartilage damage was found to be more severe in T2DM-OA rats than in DMM-induced OA rats, which can be mitigated by the intra-articular injection of SIRT3 overexpression lentivirus. Targeting SIRT3 is a potential therapeutic strategy for the alleviation of diabetic OA.

The dysregulated autophagy in osteoarthritis: Revisiting molecular profile

The risk factors of osteoarthritis (OA) are different and obesity, lifestyle, inflammation, cell death mechanisms and diabetes mellitus are among them. The changes in the biological mechanisms are considered as main regulators of OA pathogenesis. The dysregulation of autophagy is observed in different human diseases. During the pathogenesis of OA, the autophagy levels (induction or inhibition) change. The supportive and pro-survival function of autophagy can retard the progression of OA. The protective autophagy prevents the cartilage degeneration. Moreover, autophagy demonstrates interactions with cell death mechanisms and through inhibition of apoptosis and necroptosis, it improves OA. The non-coding RNA molecules can regulate autophagy and through direct and indirect control of autophagy, they dually delay/increase OA pathogenesis. The mitochondrial integrity can be regulated by autophagy to alleviate OA. Furthermore, therapeutic compounds, especially phytochemicals, stimulate protective autophagy in chondrocytes to prevent cell death. The protective autophagy has ability of reducing inflammation and oxidative damage, as two key players in the pathogenesis of OA.

Quercetin-3-O-β-D-glucuronide attenuates osteoarthritis by inhibiting cartilage extracellular matrix degradation and inflammation

Objective

Osteoarthritis (OA) is a chronic degenerative joint disease characterized by cartilage damage. In order to find a safer and more effective drug to treat OA, we investigated the role of quercetin-3-O-β-D-glucuronide (Q3GA) in OA.

Methods

We used qRT-PCR and western blots to detect the effects of Q3GA on extracellular matrix (ECM) and inflammation related genes and proteins in interleukin-1β (IL-1β) induced chondrocytes. We determined the effect of Q3GA on the NF-κB pathway using western blots and immunofluorescence. Moreover, the effect of Q3GA on the Nrf2 pathway was evaluated through molecular docking, western blots, and immunofluorescence experiments and further validated by transfection with Nrf2 siRNA. Subsequently, we established a rat model of OA and injected Q3GA into the joint cavity for treatment. After 5 weeks of Q3GA administration, samples were obtained for micro-computed tomography scanning and histopathological staining to determine the effects of Q3GA on OA rats.

Results

We found that Q3GA reduced the degradation of ECM and the expression of inflammatory related proteins and genes in primary chondrocytes of rats induced by IL-1β, as well as the expression of nitric oxide (NO) and reactive oxygen species (ROS). It inhibited the activation of the NF-κB pathway by increasing the expression of Nrf2 in the nucleus. In addition, Q3GA inhibited cartilage degradation in OA rats and promoted cartilage repair.

Conclusion

Q3GA attenuates OA by inhibiting ECM degradation and inflammation via the Nrf2/NF-κB axis.

The translational potential of this article

The results of our study demonstrate the promising potential of Q3GA as a candidate drug for the treatment of OA and reveal its key mechanisms.

Inhibition of Sirt3 activates the cGAS-STING pathway to aggravate hepatocyte damage in hepatic ischemia-reperfusion injury mice

Hepatic ischemia-reperfusion injury (IRI) typically manifests during subtotal hepatectomy and inflicts substantial damage to liver function in the perioperative period. Although the central role of cGAS-STING-mediated immune inflammation in hepatocyte damage during hepatic IRI is acknowledged, the precise regulatory mechanisms remain elusive. The current study aims to elucidate how Sirt3 inhibition activates the cGAS-STING pathway and exacerbates hepatocyte damage in hepatic IRI. We established both in vivo and in vitro models by creating hepatic IRI mice model and subjecting AML-12 hepatocyte cell lines to oxygen-glucose deprivation/reperfusion (OGD/R). Hepatic IRI compromised liver and mitochondrial function while elevating cytosolic mitochondrial DNA (mtDNA) levels in hepatocytes. Additionally, both in vivo hepatic IRI and in vitro OGD/R induced increased phosphorylation and activation of cGAS, STING, and IRF3, accompanied by heightened levels of pro-inflammatory factors, including TNF-α, IL-1β, and type I interferon (IFN-β). Importantly, knockdown of cGAS or STING through siRNA effectively attenuated hepatic IRI-induced inflammation and ameliorated liver function in both experimental settings, underscoring the dynamic involvement of the cGAS-STING pathway in hepatic IRI-induced inflammation. Furthermore, we observed a significant reduction in Sirt3 expression following hepatic IRI, both in vivo and in vitro. Then we generated Sirt3-deficient mice and applied Sirt3 knockdown in AML-12 hepatocytes. Notably, Sirt3 deficiency led to increased phosphorylation and activation of cGAS, STING, and IRF3, coupled with elevated TNF-α, IL-1β, and IFN-β levels in both in vivo and in vitro conditions. Moreover, upon silencing various downstream targets of Sirt3, such as transcription factors Sp1, Pu1, and p65, we observed that specifically knocking down p65 in AML-12 hepatocytes reduced cGAS mRNA levels. Co-immunoprecipitation assays confirmed a direct interaction between Sirt3 and p65. The absence of Sirt3 significantly increased nuclear translocation of p65 in mice, whereas Sirt3 knockdown in AML-12 hepatocytes heightened nuclear translocation of p65. ChIP-PCR assays demonstrated that Sirt3 deficiency notably enhanced the binding of p65 to two cGAS promoters, ultimately promoting cGAS transcription. Collectively, our results underscored that inhibition of Sirt3 activates the cGAS-STING pathway to aggravate hepatocyte damage by increasing cytosolic mtDNA and promoting nuclear translocation of p65 to promote cGAS transcription in hepatic IRI. These findings hold promise for potential therapeutic interventions in hepatic IRI by targeting the Sirt3-cGAS-STING axis, offering new avenues for the development of clinical strategies to mitigate liver damage during the perioperative period.

Association between niacin intake and knee osteoarthritis pain and function: a longitudinal cohort study

BACKGROUND

This research investigates the relationship between niacin intake and knee osteoarthritis (OA) severity, focusing on pain and functional ability due to niacin's role as a NAD(P)+ precursor, promoting cellular energy, and offering anti-inflammatory, analgesic, and antioxidant effects.

METHODS

The population-based Osteoarthritis Initiative (OAI) cohort with radiographically confirmed knee OA was analyzed through a Food Frequency Questionnaire determining niacin intake and scores from the Knee Injury and Osteoarthritis Outcome Score (KOOS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), using generalized additive mixed models.

RESULTS

A significant correlation was pinpointed in 2375 OA patients (1001 men and 1374 women; 55.96% aged between 45 and 65 and 44.04% aged ≥65) between niacin intake and reduced knee pain and functional degrees after a 48-month follow-up, evident in improved KOOS and WOMAC scores (P < 0.05). The fully adjusted models estimated a decrease of 0.26 points for every additional 1 unit of Ln-niacin intake of daily niacin intake on the WOMAC pain subscale, 0.83 points on the WOMAC function subscale, and an increase of 1.71 and 1.58 on the KOOS pain and quality of life score. Strikingly, subgroups including middle-aged individuals, women, white race, obese individuals, and those with specific dietary habits showed a more substantial improvement with increased niacin.

CONCLUSION

The association between increased niacin intake and reduced pain and function scores, as well improved quality of life in knee OA patients, is significant. Certain cohorts, according to a stratified analysis, could see more considerable benefits with increased niacin consumption.

HIGHLIGHTS

• Increased niacin intake is linked to reduced knee pain and better function in OA patients. • Specific subgroups, such as middle-aged individuals, women, and those with certain dietary habits, benefit more from increased niacin consumption. • Niacin shows promise for enhancing the quality of life in knee OA patients by reducing pain and improving function.

Anti-osteoarthritis, Bone Protective and Antiinflammatory Effect of Lusianthridin against Monosodium Iodoacetate Induced Osteoarthritis via Suppression of Inflammatory Pathway

Osteoarthritis (OA) is characterized by the gradual deterioration and worsening of the knee joint, leading to both pain and deformity. The current research exhibited the anti-osteoarthritis effect of lusianthridin against monosodium iodoacetate (MIA) induced OA in rats. RAW cells were used for the cell viability. The inflammatory cytokines and mediators were estimated in the cell lines after the lipopolysaccharide (LPS) treatment. For the in vivo study, the rats were received the intraperitoneal administration of MIA (3 mg/kg) for the induction of OA. The rats were received the oral administration of lusianthridin (5, 10 and 20 mg/kg) and the body and organ weight estimated. Antioxidant, cytokines, inflammatory and matrix metalloproteinases (MMP) level were also estimated. The mRNA expression of MMP were also estimated. The lusianthridin treatment remarkably suppressed the cell viability. LPS induced RAW cell suppressed the level of nitrate, tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), cyclooxygenase-2 (COX-2), prostaglandin (PGE2), MMP-2 and MMP-9 level. Lusianthridin remarkably altered the level of body weight and organ weight (liver, spleen, renal and heart weight). lusianthridin suppressed the oxidative stress via altered the level of antioxidant parameters. Lusianthridin significantly (p < 0.001) decreased the level of cartilage oligometrix matrix protein (COMP) and c-reactive protein (CRP); cytokines such as TNF-α, IL-1β, IL-6, IL-10; inflammatory parameters include 5- Lipoxygenase (5-LOX), COX-2, leukotriene B4 (LTB4), PGE2; transforming growth factor beta (TGF-β); MMP level like MMP-1, 3, 9, 13, respectively. Lusianthridin significantly suppressed the mRNA expression of MMP. Collectively, the result of the study showed that antiosteoarthritis effect of lusianthridin via suppression of inflammatory parameters.

Role of SIRT3 in bone homeostasis and its application in preventing and treating bone diseases

Bone homeostasis refers to the balance between osteoblast-mediated bone formation and osteoclast-mediated bone resorption and the maintenance of stable bone mass. SIRT3 is a class of mitochondrial protein deacetylase that influences various mitochondrial functions and is involved in the mechanisms underlying resistance to aging; regulation of bone marrow mesenchymal stem cells, osteoblasts, and osteoclasts; and development of osteoporosis, osteoarthritis, and other bone diseases. Moreover, exercise affects bones through SIRT3. Thus, studies on SIRT3 may provide insights for the treatment of bone diseases. Although SIRT3 can exert multiple effects on bone, the specific mechanism by which it regulates bone homeostasis remains unclear. By evaluating the relevant literature, this review discusses the structure and function of SIRT3, reveals the role and associated mechanisms of SIRT3 in regulating bone homeostasis and mediating bone health during exercise, and highlights the potential pharmacological value of SIRT3 in treating bone diseases.

Tetrahydrocurcumin ameliorates postinfarction cardiac dysfunction and remodeling by inhibiting oxidative stress and preserving mitochondrial function via SIRT3 signaling pathway

BACKGROUND

Myocardial infarction (MI) often leads to sudden cardiac death. Persistent myocardial ischemia increases oxidative stress and impairs mitochondrial function, contributing significantly to postinfarction cardiac dysfunction and remodeling, and the subsequent progression to heart failure (HF). Tetrahydrocurcumin (THC), isolated from the rhizome of turmeric, has antioxidant properties and has been shown to protect against cardiovascular diseases. However, its effects on HF after MI are poorly understood.

PURPOSE

The objective was the investigation of the pharmacological effects of THC and its associated mechanisms in the pathogenesis of HF after MI.

METHODS

A total of 120 mice (C57BL/6, male) were used for the in vivo experiments. An MI mouse model was created by permanent ligation of the left anterior descending coronary artery. The mice received oral dose of THC at 120 mg/kg/d and the effects on MI-induced myocardial injury were evaluated by assessment of cardiac function, histopathology, myocardial oxidative levels, and mitochondrial function. Molecular mechanisms were investigated by intraperitoneal injection of 50 mg/kg of the SIRT3 selective inhibitor 3-TYP. Meanwhile, mouse neonatal cardiomyocytes were isolated and cultured in a hypoxic incubator to verify the effects of THC in vitro. Lastly, SIRT3 and Nrf2 were silenced using siRNAs to further explore the regulatory mechanism of key molecules in this process.

RESULTS

The mouse hearts showed significant impairment in systolic function after MI, together with enlarged infarct size, increased myocardial fibrosis, cardiac hypertrophy, and apoptosis of cardiomyocytes. A significant reversal of these changes was seen after treatment with THC. Moreover, THC markedly reduced reactive oxygen species generation and protected mitochondrial function, thus mitigating oxidative stress in the post-MI myocardium. Mechanistically, THC counteracted reduced Nrf2 nuclear accumulation and SIRT3 signaling in the MI mice while inhibition of Nrf2 or SIRT3 reversed the effects of THC. Cell experiments showed that Nrf2 silencing markedly reduced SIRT3 levels and deacetylation activity while inhibition of SIRT3 signaling had little impact on Nrf2 expression.

CONCLUSION

This is the first demonstration that THC protects against the effects of MI. THC reduced both oxidative stress and mitochondrial damage by regulating Nrf2-SIRT3 signaling. The results suggest the potential of THC in treating myocardial ischemic diseases.

PM2.5 contributed to pulmonary epithelial senescence and ferroptosis by regulating USP3-SIRT3-P53 axis

Pulmonary epithelial cells act as the first line of defense against various air pollutant particles. Previous studies have reported that particulate matter 2.5 (PM2.5) could trigger pulmonary inflammation and fibrosis by inducing pulmonary epithelial senescence and ferroptosis. Sirtuin 3 (SIRT3) is one of critical the mitochondrial NAD+-dependent deacetylases, exerting antioxidant and anti-aging effects in multiple diseases. The present study aimed to explore the role of SIRT3 in PM2.5-induced lung injury as well as possible mechanisms. The role of SIRT3 in PM2.5-induced lung injury was investigated by SIRT3 genetic depletion, adenovirus-mediated overexpression in type II alveolar epithelial (AT2) cells, and pharmacological activation by melatonin. The protein level and activity of SIRT3 in lung tissues and AT2 cells were significantly downregulated after PM2.5 stimulation. SIRT3 deficiency in AT2 cells aggravated inflammatory response and collagen deposition in PM2.5-treated lung tissues. RNA-sequence and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that the differentially expressed genes (DEGs) between SIRT3 flox and SIRT3 CKO mice were mainly enriched in ferroptosis and cellular longevity. Western blot further showed that SIRT3 deficiency in AT2 cells significantly upregulated the proteins associated with ferroptosis and cell senescence in PM2.5-treated lung tissues. In vitro experiments also showed that SIRT3 overexpression could decrease the levels of ferroptosis and cell senescence in PM2.5-treated AT2 cells. In addition, we found that PM2.5 could increase the acetylation of P53 via triggering DNA damage in AT2 cells. And SIRT3 could deacetylate P53 at lysines 320 (K320), thus reducing its transcriptional activity. PM2.5 decreased the protein level of SIRT3 by inducing proteasome pathway through downregulating USP3. Finally, we found that SIRT3 agonist, melatonin treatment could alleviate PM2.5-induced senescence and ferroptosis in mice. In conclusion, targeting USP3-SIRT3-P53 axis may be a novel therapeutic strategy against PM2.5-induced pulmonary inflammation and fibrosis by decreasing pulmonary epithelial senescence and ferroptosis.

A Genome-Wide Association Study Meta-Analysis of Alpha Angle Suggests Cam-Type Morphology May Be a Specific Feature of Hip Osteoarthritis in Older Adults

OBJECTIVE

To examine the genetic architecture of cam morphology using alpha angle (AA) as a proxy measure and conduct an AA genome-wide association study (GWAS) followed by Mendelian randomization (MR) to evaluate its causal relationship with hip osteoarthritis (OA).

METHODS

Observational analyses examined associations between AA measurements derived from hip dual x-ray absorptiometry (DXA) scans from the UK Biobank study and radiographic hip OA outcomes and subsequent total hip replacement. Following these analyses, an AA GWAS meta-analysis was performed (N = 44,214) using AA measurements previously derived in the Rotterdam Study. Linkage disequilibrium score regression assessed the genetic correlation between AA and hip OA. Genetic associations considered significant (P < 5 × 10-8 ) were used as AA genetic instrument for 2-sample MR analysis.

RESULTS

DXA-derived AA showed expected associations between AA and radiographic hip OA (adjusted odds ratio [OR] 1.63 [95% confidence interval (95% CI) 1.58, 1.67]) and between AA and total hip replacement (adjusted hazard ratio 1.45 [95% CI 1.33, 1.59]) in the UK Biobank study cohort. The heritability of AA was 10%, and AA had a moderate genetic correlation with hip OA (rg  = 0.26 [95% CI 0.10, 0.43]). Eight independent genetic signals were associated with AA. Two-sample MR provided weak evidence of causal effects of AA on hip OA risk (inverse variance weighted OR 1.84 [95% CI 1.14, 2.96], P = 0.01). In contrast, genetic predisposition for hip OA had stronger evidence of a causal effect on increased AA (inverse variance weighted β = 0.09 [95% CI 0.04, 0.13], P = 4.58 × 10-5 ).

CONCLUSION

Expected observational associations between AA and related clinical outcomes provided face validity for the DXA-derived AA measurements. Evidence of bidirectional associations between AA and hip OA, particularly for risk of hip OA on AA, suggests that hip shape modeling secondary to a genetic predisposition to hip OA contributes to the well-established relationship between hip OA and cam morphology in older adults.

Research progress and hot spot analysis related to oxidative stress and osteoarthritis: a bibliometric analysis

BACKGROUND

Osteoarthritis, a common degenerative osteochondral disease, has a close relationship between its mechanism of occurrence and oxidative stress. However, there are relatively few relevant studies in this field, and a more mature research system has not yet been formed.

METHODS

By searching the Web of Science (WOS) database, we obtained 1 412 publications in the field of osteoarthritis and oxidative stress. The search results were then analyzed bibliometrically using Citespace and VOSviewer, including a study of publication trends in the field, analysis of core authors, analysis of countries and institutions with high contributions, analysis of core journals, and to identify research trends and hot spots in the field, we performed keyword clustering.

RESULTS

We collected 1 412 publications on the field of osteoarthritis and oxidative stress from 1998-2022. By analyzing the publication trends in the field, we noted an exponential increase in the number of publications per year since 2014. We then identified the core authors in the field (Blanco, Francisco J., Loeser, Richard F., Vaamonde-garcia, et.al) as well as the countries (China, USA, Italy et.al) and institutions (Xi An Jiao Tong Univ, Wenzhou Med Univ, Zhejiang Univ et.al). The OSTEOARTHRITIS AND CARTILAGE and INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES contain a large number of research papers in this field, and through keyword co-occurrence analysis, we counted 3 227 keywords appearing in the field of osteoarthritis and oxidative stress. These keywords were clustered into 9 groups, representing 9 different research hotspots.

CONCLUSIONS

Research in the field of osteoarthritis and oxidative stress has been developing since 1998 and is now maturing, but there is an urgent need to strengthen international academic exchanges and discuss the future focus of research development in the field of osteoarthritis and oxidative stress.

HIF-1α Mediates Arsenic-Induced Metabolic Reprogramming in Lung Bronchial Epithelial Cells

Arsenic is a common environmental pollutant that can cause damage to multiple systems and organs in the body. The lungs are particularly sensitive to arsenic exposure, and respiratory disease is thought to be the leading cause of death from arsenic poisoning. Our previous study found that human bronchial epithelial (HBE) cells treated with NaAsO₂ exhibited mitochondrial dysfunction accompanied by elevated HIF-1α; however, the molecular mechanism was unclear. The aim of the current study was to confirm the role of HIF-1α in arsenic-induced mitochondrial damage. The results of this study indicated that NaAsO₂ treatment induced mitochondrial ultrastructure impairment and depolarization of the mitochondrial membrane potential. Furthermore, NaAsO₂ induced a significant decrease in basal respiration, maximal respiration, spare respiratory capacity, ATP (adenosine-triphosphate)-associated mitochondrial respiration and proton leakage in HBE cells (P < 0.05), while promoting an increase in ECAR (extracellular acidification rate) values. To clarify the role of HIF-1α, the effect of HIF-1α siRNA on NaAsO₂-induced glycolysis in HBE cells was examined, and the results showed that HIF-1α siRNA reversed the NaAsO₂-induced elevation in PKM2 (Tyr105), HIF-1α, GLUT1 and HK2 protein expression and decreased the NaAsO₂-mediated glycolysis level, glycolytic capacity and glycolytic reserve. These findings suggest that targeting metabolic dysregulation has significant implications for targeting arsenic-induced lung injury and that HIF-1α is an exciting new therapeutic target for the treatment of arsenic-induced lung injury.

Sirtuin-3: A potential target for treating several types of brain injury

Sirtuin-3 (SIRT3) is responsible for maintaining mitochondrial homeostasis by deacetylating substrates in an NAD+-dependent manner. SIRT3, the primary deacetylase located in the mitochondria, controls cellular energy metabolism and the synthesis of essential biomolecules for cell survival. In recent years, increasing evidence has shown that SIRT3 is involved in several types of acute brain injury. In ischaemic stroke, subarachnoid haemorrhage, traumatic brain injury, and intracerebral haemorrhage, SIRT3 is closely related to mitochondrial homeostasis and with the mechanisms of pathophysiological processes such as neuroinflammation, oxidative stress, autophagy, and programmed cell death. As SIRT3 is the driver and regulator of a variety of pathophysiological processes, its molecular regulation is significant. In this paper, we review the role of SIRT3 in various types of brain injury and summarise SIRT3 molecular regulation. Numerous studies have demonstrated that SIRT3 plays a protective role in various types of brain injury. Here, we present the current research available on SIRT3 as a target for treating ischaemic stroke, subarachnoid haemorrhage, traumatic brain injury, thus highlighting the therapeutic potential of SIRT3 as a potent mediator of catastrophic brain injury. In addition, we have summarised the therapeutic drugs, compounds, natural extracts, peptides, physical stimuli, and other small molecules that may regulate SIRT3 to uncover additional brain-protective mechanisms of SIRT3, conduct further research, and provide more evidence for clinical transformation and drug development.

Gastrodin alleviates rat chondrocyte senescence and mitochondrial dysfunction through Sirt3

Several researchers have focused on understanding the pathogenesis and treatment strategies for osteoarthritis (OA). Gastrodin (GAS) is a potential anti-inflammatory agent. In this study, we constructed an in vitro OA chondrocyte model by treating chondrocytes with IL-1β. Next, we determined the expression of aging-related markers and mitochondrial functions in chondrocytes treated with GAS. Further, we constructed a "drug-component-target-pathway-disease" interactive network and determined the effect of GAS on the functions and pathways related to OA. Finally, we constructed the OA rat model by removing the medial meniscus of the right knee and transection of the anterior cruciate ligament. The results revealed that GAS reduced senescence and improved mitochondrial functions in OA chondrocytes. We used network pharmacology and bioinformatics to screen for key molecules Sirt3 and the PI3K-AKT pathway involved in regulating the effect of GAS on OA. Further studies showed an increase in SIRT3 expression and reduced chondrocyte aging, mitochondrial damage, and the phosphorylation of the PI3K-AKT pathway. The results showed that GAS ameliorates pathological changes related to aging, increases SIRT3 expression, and protects the ECM in the OA rat model. These results were consistent with our bioinformatics results and previous studies. In summary, GAS slows down the aging of chondrocytes and mitochondrial damage in OA by regulating the phosphorylation of the PI3K-AKT pathway via SIRT3.

Aging-Related Ovarian Failure and Infertility: Melatonin to the Rescue

Aging has a major detrimental effect on the optimal function of the ovary with changes in this organ preceding the age-related deterioration in other tissues, with the middle-aged shutdown leading to infertility. Reduced fertility and consequent inability to conceive by women in present-day societies who choose to have children later in life leads to increased frustration. Melatonin is known to have anti-aging properties related to its antioxidant and anti-inflammatory actions. Its higher follicular fluid levels relative to blood concentrations and its likely synthesis in the oocyte, granulosa, and luteal cells suggest that it is optimally positioned to interfere with age-associated deterioration of the ovary. Additionally, the end of the female reproductive span coincides with a significant reduction in endogenous melatonin levels. Thus, the aims are to review the literature indicating melatonin production in mitochondria of oocytes, granulosa cells, and luteal cells, identify the multiple processes underlying changes in the ovary, especially late in the cessation of the reproductive life span, summarize the physiological and molecular actions of melatonin in the maintenance of normal ovaries and in the aging ovaries, and integrate the acquired information into an explanation for considering melatonin in the treatment of age-related infertility. Use of supplemental melatonin may help preserve fertility later in life and alleviate frustration in women delaying childbearing age, reduce the necessity of in vitro fertilization–embryo transfer (IVF-ET) procedures, and help solve the progressively increasing problem of non-aging-related infertility in women throughout their reproductive life span. While additional research is needed to fully understand the effects of melatonin supplementation on potentially enhancing fertility, studies published to date suggest it may be a promising option for those struggling with infertility.

Isorhynchophylline alleviates cartilage degeneration in osteoarthritis by activating autophagy of chondrocytes

CONTEXT

Osteoarthritis is a common degenerative disease, the cause of it is still unknown, and the treatment mainly focuses on improving symptoms. Studies have found that Isorhynchophylline (Isorhy) has antioxidant, anti-inflammatory, antiproliferative and neuroprotective effects.

OBJECTIVE

This study investigates the role and mechanism of Isorhy in OA.

METHODS

The destabilized medial meniscus model was used to mimic OA. Fifteen male Sprague Dawley rats were partitioned into three portions: Normal group, OA group (surgery; normal saline treatment) and OA + Isorhy group (surgery; 50 μM Isorhy treatment) were performed on the first day of every week from the 5th to the 8th week after surgery. After 4 weeks of drug treatment, the rats have been processed without debridement of the knee specimens and fixed using 4% paraformaldehyde for two days. The morphological analysis was performed by H&E, Safranin O-Fast green staining and micro-CT analysis. The specimens were researched employing Micro-CT. In the part of the aggregate methods that were evaluated by qRT-PCR and western blot of the following proteins LC3II/LC3I, Beclin-1, ATG5, ATG7, MMP3 andMMP13. Akt/PI3K signaling related proteins (p-AKT, AKT, p-PI3K, PI3K, p-mTOR, mTOR) were detected by Western blot. BECLIN1 and MMP3 were detected by Immunofluorescence assay.

RESULTS

In this present research, it was proved that autophagy-related and cartilage matrix-related proteins in osteoarthritis could be regulated by Isorhynchophylline treatment. The transcriptome sequencing results suggested the regulation was closely associated with PI3K/AKT/mTOR pathway, thereby alleviating osteoarticular inflammation. In-depth study showed that Isorhy could also affect OA in rat OA models, that was indicated by H&E, Safranin O-Fast green staining, and also micro-CT analysis.

CONCLUSION

Our findings indicated that Isorhy could be regarded as a prospective candidate for OA treatment.

Role of reactive oxygen species and mitochondrial damage in rheumatoid arthritis and targeted drugs

Rheumatoid arthritis (RA) is an autoimmune disease characterized by synovial inflammation, pannus formation, and bone and cartilage damage. It has a high disability rate. The hypoxic microenvironment of RA joints can cause reactive oxygen species (ROS) accumulation and mitochondrial damage, which not only affect the metabolic processes of immune cells and pathological changes in fibroblastic synovial cells but also upregulate the expression of several inflammatory pathways, ultimately promoting inflammation. Additionally, ROS and mitochondrial damage are involved in angiogenesis and bone destruction, thereby accelerating RA progression. In this review, we highlighted the effects of ROS accumulation and mitochondrial damage on inflammatory response, angiogenesis, bone and cartilage damage in RA. Additionally, we summarized therapies that target ROS or mitochondria to relieve RA symptoms and discuss the gaps in research and existing controversies, hoping to provide new ideas for research in this area and insights for targeted drug development in RA.

The role of Sirt3-induced autophagy in renal structural damage caused by periodontitis in rats

OBJECTIVE

This research aimed to explore the effect of periodontitis on renal tissues injury in rats and the role of Sirtuin3 (Sirt3) and its regulation of autophagy in this progression.

MATERIAL AND METHODS

Thirty Wistar rats were assigned into three groups: control, periodontitis (P), and periodontitis with gavage administration of Sirt3 activator resveratrol (P + RSV). To induce periodontitis, the wire ligature was placed around the cervical region of the rat maxillary first molar. After 8 weeks, micro-computed tomography (Micro-CT) and hematoxylin and eosin (HE) were used to evaluate the alveolar bone resorption and periodontal inflammation. Serum and urine biochemical indicators were measured to assess renal function. The pathological changes of the kidney were observed via HE and periodic acid Schiff (PAS) staining. Autophagosome was viewed by transmission electron microscopy (TEM). Real-time PCR and western blot were used to test expressions of Sirt3 and autophagy indicators in renal and periodontal tissues, including mammalian target of rapamycin (mTOR), phosphor-mTOR (p-mTOR), BECN1 (Beclin-1), and microtubule-associated protein 1 light chain 3 (LC3).

RESULTS

Alveolar bone destruction, resorption, and periodontal inflammation were observed in the P group (compared with the control group), and the above indexes were significantly improved after RSV intervention; the obvious changes in renal tissue structure in the P group were partially recovered after RSV intervention, while renal functional status was not affected (among the three groups); in addition, the levels of Sirt3 and autophagy in kidney and periodontal tissues of P group were inhibited, manifested as a decrease in the number of autophagosomes (renal tissue) and expressions of autophagy marker Beclin-1 and LC3 conversion rate and an increase in the expression of p-mTOR. After Sirt3 activation (RSV), the above indicators were significantly improved.

CONCLUSION

Periodontitis causes renal structural damage in rats, which may be connected to the effect of Sirt3-induced autophagy.

Sirtuins in osteoarthritis: current understanding

Osteoarthritis (OA) is a common disease characterized by severe chronic joint pain, that imposes a large burden on elderly people. OA is a highly heterogeneous disease, and multiple etiologies contribute to its progression. Sirtuins (SIRTs) are Class III histone deacetylases (HDACs) that regulate a comprehensive range of biological processes such as gene expression, cell differentiation, and organism development, and lifespan. Over the past three decades, increasing evidence has revealed that SIRTs are not only important energy sensors but also protectors against metabolic stresses and aging, and an increasing number of studies have focused on the functions of SIRTs in OA pathogenesis. In this review, we illustrate the biological functions of SIRTs in OA pathogenesis from the perspectives of energy metabolism, inflammation, autophagy and cellular senescence. Moreover, we offer insights into the role played by SIRTs in regulating circadian rhythm, which has recently been recognized to be crucial in OA development. Here, we provide the current understanding of SIRTs in OA to guide a new direction for OA treatment exploration.

Methyl gallate prevents oxidative stress induced apoptosis and ECM degradation in chondrocytes via restoring Sirt3 mediated autophagy and ameliorates osteoarthritis progression

Osteoarthritis (OA) is a common age-related degenerative disease involving various pathological processes, among which apoptosis in chondrocyte and extracellular matrix (ECM) degradation are the main pathologies. Previous studies have shown that autophagy has a protective effect on apoptosis and ECM degradation in chondrocytes. Methyl gallate (MG) is a natural polyphenol from various medicinal and edible plants. Moreover, several studies have demonstrated that MG exerts multiple pharmacological effects in various diseases, including anti-inflammatory, antioxidant, and anti-apoptosis. Hence, in this study, we investigate the protective effect of MG on the pathological process of OA in cellular and mice OA model to elucidate the underlying molecular mechanism. In vitro, MG treatment inhibits the expression of pro-apoptotic proteins and promotes the expression of anti-apoptotic proteins under TBHP stimulation. Meanwhile, MG treatment promotes the expression of Collagen II and Aggrecan and inhibits the expression of matrix-degrading enzymes thrombospondin motifs 5 (ADAMTS5) and matrix metalloproteinase-13 (MMP13), which lead to ECM degradation. Furthermore, in terms of mechanism, MG treatment enhances autophagy by upregulating SIRT3 expression, and inhibition of autophagy could eliminate the protective effect of MG on chondrocytes in terms of anti-apoptosis and ECM synthesis. The protective effect of MG on OA has also been observed in mice OA model. In brief, our study suggests that MG could be a potential candidate for the treatment of 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.

Sirt3 mitigates LPS-induced mitochondrial damage in renal tubular epithelial cells by deacetylating YME1L1

Acute kidney injury (AKI) is often secondary to sepsis. Increasing evidence suggests that mitochondrial dysfunction contributes to the pathological process of AKI. In this study, we aimed to examine the regulatory roles of Sirt3 in Lipopolysaccharide (LPS)-induced mitochondrial damage in renal tubular epithelial cells (TECs). Sirt3 knockout mice were intraperitoneally injected with LPS, and cultured TECs were stimulated with LPS to evaluate the effects of Sirt3 on mitochondrial structure and function in TECs. Electron microscopy was used to assess mitochondrial morphology. Immunofluorescence staining was performed to detect protein expression and examine mitochondrial morphology. Western blotting was used to quantify protein expression. We observed that LPS increased apoptosis, induced disturbances in mitochondrial function and dynamics, and downregulated Sirt3 expression in a sepsis-induced AKI mouse model and human proximal tubular (HK-2) cells in vitro. Sirt3 deficiency further exacerbated LPS-induced renal pathological damage, apoptosis and disturbances in mitochondrial function and dynamics. On the contrary, Sirt3 overexpression in HK-2 cells alleviated these lesions. Functional studies revealed that Sirt3 overexpression alleviated LPS-induced mitochondrial damage and apoptosis in TECs by promoting OPA1-mediated mitochondrial fusion through the deacetylation of i-AAA protease (YME1L1), an upstream regulatory molecule of OPA1. Our study has identified Sirt3 as a vital factor that protects against LPS-induced mitochondrial damage and apoptosis in TECs via the YME1L1-OPA1 signaling pathway.

Mitophagy—A New Target of Bone Disease

Bone diseases are usually caused by abnormal metabolism and death of cells in bones, including osteoblasts, osteoclasts, osteocytes, chondrocytes, and bone marrow mesenchymal stem cells. Mitochondrial dysfunction, as an important cause of abnormal cell metabolism, is widely involved in the occurrence and progression of multiple bone diseases, including osteoarthritis, intervertebral disc degeneration, osteoporosis, and osteosarcoma. As selective mitochondrial autophagy for damaged or dysfunctional mitochondria, mitophagy is closely related to mitochondrial quality control and homeostasis. Accumulating evidence suggests that mitophagy plays an important regulatory role in bone disease, indicating that regulating the level of mitophagy may be a new strategy for bone-related diseases. Therefore, by reviewing the relevant literature in recent years, this paper reviews the potential mechanism of mitophagy in bone-related diseases, including osteoarthritis, intervertebral disc degeneration, osteoporosis, and osteosarcoma, to provide a theoretical basis for the related research of mitophagy in bone diseases.

The Role of Mitochondrial Quality Control in Anthracycline-Induced Cardiotoxicity: From Bench to Bedside

Cardiotoxicity is the major side effect of anthracyclines (doxorubicin, daunorubicin, epirubicin, and idarubicin), though being the most commonly used chemotherapy drugs and the mainstay of therapy in solid and hematological neoplasms. Advances in the field of cardio-oncology have expanded our understanding of the molecular mechanisms underlying anthracycline-induced cardiotoxicity (AIC). AIC has a complex pathogenesis that includes a variety of aspects such as oxidative stress, autophagy, and inflammation. Emerging evidence has strongly suggested that the loss of mitochondrial quality control (MQC) plays an important role in the progression of AIC. Mitochondria are vital organelles in the cardiomyocytes that serve as the key regulators of reactive oxygen species (ROS) production, energy metabolism, cell death, and calcium buffering. However, as mitochondria are susceptible to damage, the MQC system, including mitochondrial dynamics (fusion/fission), mitophagy, mitochondrial biogenesis, and mitochondrial protein quality control, appears to be crucial in maintaining mitochondrial homeostasis. In this review, we summarize current evidence on the role of MQC in the pathogenesis of AIC and highlight the therapeutic potential of restoring the cardiomyocyte MQC system in the prevention and intervention of AIC.

Mitochondria-Targeted Antioxidant Mitoquinone Maintains Mitochondrial Homeostasis through the Sirt3-Dependent Pathway to Mitigate Oxidative Damage Caused by Renal Ischemia/Reperfusion

Mitochondrial dysfunction is a critical factor contributing to oxidative stress and apoptosis in ischemia-reperfusion (I/R) diseases. Mitoquinone (MitoQ) is a mitochondria-targeted antioxidant whose potent anti-I/R injury capacity has been demonstrated in organs such as the heart and the intestine. In the present study, we explored the role of MitoQ in maintaining mitochondrial homeostasis and attenuating oxidative damage in renal I/R injury. We discovered that the decreased renal function and pathological damage caused by renal I/R injury were significantly ameliorated by MitoQ. MitoQ markedly reversed mitochondrial damage after I/R injury and inhibited renal reactive oxygen species production. In vitro, hypoxia/reoxygenation resulted in increased mitochondrial fission and decreased mitochondrial fusion in human renal tubular epithelial cells (HK-2), which were partially prevented by MitoQ. MitoQ treatment inhibited oxidative stress and reduced apoptosis in HK-2 cells by restoring mitochondrial membrane potential, promoting ATP production, and facilitating mitochondrial fusion. Deeply, renal I/R injury led to a decreased expression of sirtuin-3 (Sirt3), which was recovered by MitoQ. Moreover, the inhibition of Sirt3 partially eliminated the protective effect of MitoQ on mitochondria and increased oxidative damage. Overall, our data demonstrate a mitochondrial protective effect of MitoQ, which raises the possibility of MitoQ as a novel therapy for renal I/R.

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

Osteoarthritis (OA), a chronic degenerative disease with heterogeneous properties, is difficult to cure due to its complex pathogenesis. Curcumin possesses excellent anti-inflammatory and antioxidant properties and may have potential therapeutic value in OA. In this study, we investigated the action targets of curcumin and identified potential anti-OA targets for curcumin. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) signaling pathway analyses were performed to evaluate these targets. Furthermore, we established a sodium monoiodoacetate-induced rat knee OA model and IL-1β induced OA chondrocyte model to verify the effect and mechanism of curcumin against OA. The GO and KEGG analyses screened seven hub genes involved in metabolic processes and the AMPK signaling pathway. Curcumin can significantly attenuate OA characteristics according to Osteoarthritis Research Society International (OARSI) and Mankin scores in OA rats. Additionally, curcumin is notably employed as an activator of mitophagy in maintaining mitochondrial homeostasis (ROS, Ca²⁺, ATP production, and mitochondrial membrane potential). The expression levels of mitophagy-related proteins were increased not only in articular cartilage but also in chondrocytes with curcumin intervention. Combining validation experiments and network pharmacology, we identified the importance of mitophagy in the curcumin treatment of OA. The chondroprotective effects of curcumin against OA are mediated by the AMPK/PINK1/Parkin pathway, and curcumin may serve as a potential novel drug for OA management.

Hydrogel platform with tunable stiffness based on magnetic nanoparticles cross-linked GelMA for cartilage regeneration and its intrinsic biomechanism

Cartilage injury affects numerous individuals, but the efficient repair of damaged cartilage is still a problem in clinic. Hydrogel is a potent scaffold candidate for tissue regeneration, but it remains a big challenge to improve its mechanical property and figure out the interaction of chondrocytes and stiffness. Herein, a novel hybrid hydrogel with tunable stiffness was fabricated based on methacrylated gelatin (GelMA) and iron oxide nanoparticles (Fe₂O₃) through chemical bonding. The stiffness of Fe₂O₃/GelMA hybrid hydrogel was controlled by adjusting the concentration of magnetic nanoparticles. The hydrogel platform with tunable stiffness modulated its cellular properties including cell morphology, microfilaments and Young's modulus of chondrocytes. Interestingly, Fe₂O₃/GelMA hybrid hydrogel promoted oxidative phosphorylation of mitochondria and facilitated catabolism of lipids in chondrocytes. As a result, more ATP and metabolic materials generated for cellular physiological activities and organelle component replacements in hybrid hydrogel group compared to pure GelMA hydrogel. Furthermore, implantation of Fe₂O₃/GelMA hybrid hydrogel in the cartilage defect rat model verified its remodeling potential. This study provides a deep understanding of the bio-mechanism of Fe₂O₃/GelMA hybrid hydrogel interaction with chondrocytes and indicates the hydrogel platform for further application in tissue engineering.

Potential Methods of Targeting Cellular Aging Hallmarks to Reverse Osteoarthritic Phenotype of Chondrocytes

Osteoarthritis (OA) is a chronic degenerative joint disease that causes pain, physical disability, and life quality impairment. The pathophysiology of OA remains largely unclear, and currently no FDA-approved disease-modifying OA drugs (DMOADs) are available. As has been acknowledged, aging is the primary independent risk factor for OA, but the mechanisms underlying such a connection are not fully understood. In this review, we first revisit the changes in OA chondrocytes from the perspective of cellular hallmarks of aging. It is concluded that OA chondrocytes share many alterations similar to cellular aging. Next, based on the findings from studies on other cell types and diseases, we propose methods that can potentially reverse osteoarthritic phenotype of chondrocytes back to a healthier state. Lastly, current challenges and future perspectives are summarized.

The Role of Mitochondrial Metabolism, AMPK-SIRT Mediated Pathway, LncRNA and MicroRNA in Osteoarthritis

Osteoarthritis (OA) is the most common joint disease characterized by degeneration of articular cartilage and causes severe joint pain, physical disability, and impaired quality of life. Recently, it was found that mitochondria not only act as a powerhouse of cells that provide energy for cellular metabolism, but are also involved in crucial pathways responsible for maintaining chondrocyte physiology. Therefore, a growing amount of evidence emphasizes that impairment of mitochondrial function is associated with OA pathogenesis; however, the exact mechanism is not well known. Moreover, the AMP-activated protein kinase (AMPK)–Sirtuin (SIRT) signaling pathway, long non-coding RNA (lncRNA), and microRNA (miRNA) are important for regulating the physiological and pathological processes of chondrocytes, indicating that these may be targets for OA treatment. In this review, we first focus on the importance of mitochondria metabolic dysregulation related to OA. Then, we show recent evidence on the AMPK-SIRT mediated pathway associated with OA pathogenesis and potential treatment options. Finally, we discuss current research into the effects of lncRNA and miRNA on OA progression or inhibition.

Dietary Choline Alleviates High-Fat Diet-Induced Hepatic Lipid Dysregulation via UPRmt Modulated by SIRT3-Mediated mtHSP70 Deacetylation

The mitochondrial unfolded protein response (UPRmt) is known as a conservative mechanism in response to mitochondrial dysfunction. Thus, based on UPRmt, this study was conducted to determine the mechanism of a high-fat diet (HFD) inducing mitochondrial dysfunction and its role in stimulating hepatic lipid dysregulation. The choline-activated alleviating effect was also evaluated. In vivo, yellow catfish were fed three diets (control, HFD, and HFD + choline diet) for 10 weeks. In vitro, hepatocytes isolated from yellow catfish and the HepG2 cell line were cultured and incubated with fatty acid (FA) for 48 h. (1) HFD-induced mitochondrial dysfunction via SIRT3/mtHSP70-mediated UPRmt. HFD inhibited the subcellular localization of SIRT3 into the mitochondrion, resulting in the up-regulating of mtHSP70 acetylation via lysine residues 493 and 507. The mtHSP70 acetylation promoted the stability of mtHSP70, which then led to the UPRmt and further mitochondrial dysfunction. (2) SIRT3/mtHSP70-mediated UPRmt regulated HFD/FA-induced hepatic lipid dysregulation. SIRT3/mtHSP70-mediated UPRmt reduced FA ß-oxidation via mitochondrial dysfunction and then led to lipid dysregulation. Additionally, the mtHSP70-ACOX1 interaction was confirmed. (3) Choline alleviated HFD-induced UPRmt via up-regulating the localization of SIRT3 into the mitochondrion, which in turn led to the subsequent ameliorating effect on HFD-induced hepatic lipid dysregulation. Through SIRT3-mediated mtHSP70 deacetylation, dietary choline alleviates HFD-induced hepatic lipid dysregulation via UPRmt. This provides the first proof of acetylation regulating UPRmt and the crosstalk between UPRmt and FA ß-oxidation.

Mitochondrial quality control in cartilage damage and osteoarthritis: new insights and potential therapeutic targets

Osteoarthritis (OA) is a multifactorial arthritic disease of weight-bearing joints concomitant with chronic and intolerable pain, loss of locomotion and impaired quality of life in the elderly population. Although the prevalence of OA increases with age, its specific mechanisms have not been elucidated and effective therapeutic disease-modifying drugs have not been developed. As essential organelles in chondrocytes, mitochondria supply energy and play vital roles in cellular metabolism, proliferation and apoptosis. Mitochondrial quality control (MQC) is the key mechanism to coordinate various mitochondrial biofunctions, primarily through mitochondrial biogenesis, dynamics, autophagy and the newly discovered mitocytosis. An increasing number of studies have revealed that a loss of MQC homeostasis contributes to the cartilage damage during the occurrence and development of OA. Several master MQC-associated signaling pathways and regulators exert chondroprotective roles in OA, while cartilage damage-related molecular mechanisms have been partially identified. In this review, we summarized known mechanisms mediated by dysregulated MQC in the pathogenesis of OA and latent bioactive ingredients and drugs for the prevention and treatment of OA through the maintenance of MQC.

[The role of chondrocyte mitochondrial biogenesis in the pathogenesis of osteoarthritis]

OBJECTIVE

To summarize the role of chondrocytes mitochondrial biogenesis in the pathogenesis of osteoarthritis (OA), and analyze the applications in the treatment of OA.

METHODS

A review of recent literature was conducted to summarize the changes in mitochondrial biogenesis in the course of OA, the role of major signaling molecules in OA chondrocytes, and the prospects for OA therapeutic applications.

RESULTS

Recent studies reveales that mitochondria are significant energy metabolic centers in chondrocytes and its dysfunction has been considered as an essential mechanism in the pathogenesis of OA. Mitochondrial biogenesis is one of the key processes maintaining the normal quantity and function of mitochondria, and peroxisome proliferator-activated receptor-gamma coactivator 1 alpha (PGC-1α) is the central regulator of this process. A regulatory network of mitochondrial biogenesis with PGC-1α as the center, adenosine monophosphate-activated protein kinase, sirtuin1/3, and cyclic adenosine monophosphate response element-binding protein as the main upstream regulatory molecules, and nuclear respiratory factor 1, estrogen-related receptor α, and nuclear respiratory factor 2 as the main downstream regulatory molecules has been reported. However, the role of mitochondrial biogenesis in OA chondrocytes still needs further validation and in-depth exploration. It has been demonstrated that substances such as puerarin and omentin-1 can retard the development of OA by activating the damaged mitochondrial biogenesis in OA chondrocytes, which proves the potential to be used in the treatment OA.

CONCLUSION

Mitochondrial biogenesis in chondrocytes plays an important role in the pathogenesis of OA, and further exploring the related mechanisms is of great clinical significance.

The Role of SIRT3 in the Osteoporosis

SIRT3 is an NAD⁺-dependent deacetylase in the mitochondria with an extensive ability to regulate mitochondrial morphology and function. It has been reported that SIRT3 participates in the occurrence and development of many aging-related diseases. Osteoporosis is a common aging-related disease characterized by decreased bone mass and fragility fractures, which has caused a huge burden on society. Current research shows that SIRT3 is involved in the physiological processes of senescence of bone marrow mesenchymal stem cells (BMSCs), differentiation of BMSCs and osteoclasts. However, the specific effects and mechanisms of SIRT3 in osteoporosis are not clear. In the current review, we elaborated on the physiological functions of SIRT3, the cell types involved in bone remodeling, and the role of SIRT3 in osteoporosis. Furthermore, it also provided a theoretical basis for SIRT3 as a therapeutic target for osteoporosis.

Hyaluronic Acid Modified Curcumin-Loaded Chitosan Nanoparticles Inhibit Chondrocyte Apoptosis to Attenuate Osteoarthritis via Upregulation of Activator Protein 1 and RUNX Family Transcription Factor 2

Hyaluronic acid (HA) and curcumin (CUR) have been previously utilized for osteoarthritis (OA) treatment. CUR-loaded chitosan nanoparticles (CUR@CS NPs) and HA CUR@CS NPs were synthesized in our research to ascertain the synergistic impacts of HA and CUR-loaded NPs on OA treatment. CUR@CS NPs and HA CUR@CS NPs were synthesized with evaluation of their particle size, potential, PDI, encapsulation efficiency, drug loading and surface coating as well as HA binding rate. The in vitro CUR release curve and stability of HA-CUR@CS NPs were measured. Chondrocytes were isolated from the cartilages of OA patients, followed by cell uptake assay. The chondrocyte viability and apoptosis were determined. Subsequently, the knee OA model was established, followed by H&E, Safranin O/Fast green staining and micro-CT. HA CUR@CS NPs improved CUR stability and bioavailability. CUR@CS NPs and HA-CUR@CS NPs were successfully characterized and could further be internalized by chondrocytes. CUR@CS NPs promoted tBHP-induced chondrocyte viability and inhibited chondrocyte apoptosis. HA-CUR@CS NPs upregulated the AP-1 and RUNX2 transcription levels to activate Hedgehog pathway, which subsequently blocked the Notch pathway. Mechanically, HA-CUR@CS NPs sustained release and long-lasting effect and long-term retention in the joint cavity and downregulated the expression of several pro-inflammatory cytokines in vivo. HA-CUR@CS NPs exhibited superior effects in the preceding experiments than CUR@CS NPs. Altogether, HA-CUR@CS NPs may restrict inflammation and chondrocyte apoptosis in OA through upregulation of AP-1 and RUNX2.

Autophagy and Polyphenols in Osteoarthritis: A Focus on Epigenetic Regulation

Autophagy is an intracellular mechanism that maintains cellular homeostasis in different tissues. This process declines in cartilage due to aging, which is correlated with osteoarthritis (OA), a multifactorial and degenerative joint disease. Several studies show that microRNAs regulate different steps of autophagy but only a few of them participate in OA. Therefore, epigenetic modifications could represent a therapeutic opportunity during the development of OA. Besides, polyphenols are bioactive components with great potential to counteract diseases, which could reverse altered epigenetic regulation and modify autophagy in cartilage. This review aims to analyze epigenetic mechanisms that are currently associated with autophagy in OA, and to evaluate whether polyphenols are used to reverse the epigenetic alterations generated by aging in the autophagy pathway.

Role of mitochondrial sirtuins in rheumatoid arthritis

AIM

Current study is intended to evaluate the expression and epigenetic variations of mitochondrial situins in 306 rheumatoid arthritis (RA) cases and compared with age/gender matched controls.

MATERIALS AND METHODS

The expression level was measured using the quantitative Real time PCR (qPCR) and epigenetic analysis was performed by measuring deacetylation activity. Oxidative stress was also measured in present study using the enzyme linked immunoassay (ELISA). The obtained results were evaluated by means of the student t-test, spearman correlation and ROC curve analysis.

RESULTS

Expression analysis showed the significant downregulation of SIRT3 (p < 0.0001), SIRT4 (p < 0.0001) and SIRT5 (p < 0.0001) in RA cases when compared with controls. Downregulation of mitochondrial sirtuins was significantly associated with positive anti-CCP status, increased ESR level and with increased CRP levels. Epigenetic analysis showed significant increased histone deacetylation in RA patients compared to controls. Co-expression analysis showed the significant negative association between expression level of mitochondrial sirtuins and deacytylation level (SIRT3 r = -0.438, p < 0.0001; SIRT4 r = -0.424, p < 0.0001; SIRT5 r = -0.282, p < 0.0001). ROC curve analysis exhibited that downregulation of mitochondrial sirtuins (SIRT3 AUC = 0.91, p < 0.001; SIRT4 AUC = 0.92, p < 0.001; SIRT5 AUC = 0.85, p < 0.001) was act as the good diagnostic marker for detection/diagnosis of arthritis.

CONCLUSIONS

The results show that significant deregulation of mitochondrial sirtuins was associated with increased arthritis risk and can be act as an indicator of advance clinical outcome.

The effect of lactoferrin in aging: role and potential

Aging is frequently accompanied by various types of physiological deterioration, which increases the risk of human pathologies. Global public health efforts to increase human lifespan have increasingly focused on lowering the risk of aging-related diseases, such as diabetes, neurodegenerative diseases, cardiovascular disease, and cancers. Dietary intervention is a promising approach to maintaining human health during aging. Lactoferrin (LF) is known for its physiologically pleiotropic properties. Anti-aging interventions of LF have proven to be safe and effective for various pharmacological activities, such as anti-oxidation, anti-cellular senescence, anti-inflammation, and anti-carcinogenic. Moreover, LF has a pivotal role in modulating the major signaling pathways that influence the longevity of organisms. Thus, LF is expected to be able to attenuate the process of aging and greatly ameliorate its effects.