SIRT3/SOD2 maintains osteoblast differentiation and bone formation by regulating mitochondrial stress

Redox signaling regulates the skeletal tissue development and regeneration

Skeletal tissue development and regeneration in mammals are intricate, multistep, and highly regulated processes. Various signaling pathways have been implicated in the regulation of these processes, including redox. Redox signaling is the signal transduction by electron transfer reactions involving free radicals or related species. Redox homeostasis is essential to cell metabolic states, as the ROS not only regulates cell biological processes but also mediates physiological processes. Following a bone fracture, redox signaling is also triggered to regulate bone healing and regeneration by targeting resident stromal cells, osteoblasts, osteoclasts and endothelial cells. This review will focus on how the redox signaling impact the bone development and bone regeneration.

Increased adrenal steroidogenesis and suppressed corticosteroid responsiveness in critical COVID-19

BACKGROUND

The effect of coronavirus disease 2019 (COVID-19) on adrenal endocrine metabolism in critically ill patients remains unclear. This study aimed to investigate the alterations in adrenal steroidogenic activity, elucidate underlying mechanisms, provide in situ histopathological evidence, and examine the clinical implications.

METHODS

The comparative analyses of the adrenal cortices from 24 patients with fatal COVID-19 and 20 matched controls were performed, excluding patients previously treated with glucocorticoids. SARS-CoV-2 and its receptors were identified and pathological alterations were examined. Furthermore, histological examinations, immunohistochemical staining and ultrastructural analyses were performed to assess corticosteroid biosynthesis. The zona glomerulosa (ZG) and zona fasciculata (ZF) were then dissected for proteomic analyses. The biological processes that affected steroidogenesis were analyzed by integrating histological, proteomic, and clinical data. Finally, the immunoreactivity and responsive genes of mineralocorticoid and glucocorticoid receptors in essential tissues were quantitatively measured to evaluate corticosteroid responsiveness.

FINDINGS

The demographic characteristics of COVID-19 patients were comparable with those of controls. SARS-CoV-2-like particles were identified in the adrenocortical cells of three patients; however, these particles did not affect cellular morphology or steroid synthesis compared with SARS-CoV-2-negative specimens. Although the adrenals exhibited focal necrosis, vacuolization, microthrombi, and inflammation, widespread degeneration was not evident. Notably, corticosteroid biosynthesis was significantly enhanced in both the ZG and ZF of COVID-19 patients. The increase in the inflammatory response and cellular differentiation in the adrenal cortices of patients with critical COVID-19 was positively correlated with heightened steroidogenic activity. Additionally, the appearance of more dual-ZG/ZF identity cells in COVID-19 adrenals was in accordance with the increased steroidogenic function. However, activated mineralocorticoid and glucocorticoid receptors and their responsive genes in vital tissues were markedly reduced in patients with critical COVID-19.

INTERPRETATION

Critical COVID-19 was characterized by potentiated adrenal steroidogenesis, associated with increased inflammation, enhanced differentiation and elevated dual-ZG/ZF identity cells, alongside suppressed corticosteroid responsiveness. These alterations implied the reduced effectiveness of conventional corticosteroid therapy and underscored the need for evaluation of the adrenal axis and corticosteroid sensitivity.

Inflammatory priming of human mesenchymal stem cells induces osteogenic differentiation via the early response gene IER3

Mesenchymal stem cells (MSCs) have gained tremendous interest due to their overall potent pro-regenerative and immunomodulatory properties. In recent years, various in vitro and preclinical studies have investigated different priming ("licensing") approaches to enhance MSC functions for specific therapeutic purposes. In this study, we primed bone marrow-derived human MSCs (hMSCs) with an inflammation cocktail designed to mimic the elevated levels of inflammatory mediators found in serum of patients with severe injuries, such as bone fractures. We observed a significantly enhanced osteogenic differentiation potential of primed hMSCs compared to untreated controls. By RNA-sequencing analysis, we identified the immediate early response 3 (IER3) gene as one of the top-regulated genes upon inflammatory priming. Small interfering RNA knockdown experiments established IER3 as a novel positive regulator of osteogenic differentiation. Mechanistic analysis further revealed that IER3 deletion significantly downregulated bone marrow stromal cell antigen 2 (BST2) expression and extracellular signal-related kinase 1/2 (ERK1/2) phosphorylation in hMSCs, suggesting that IER3 regulates osteogenic differentiation through BST2 and ERK1/2 signaling pathway activation. On the basis of these findings, we propose IER3 as a novel therapeutic target to promote hMSC osteoblastogenesis, which might be of high clinical relevance, for example, in patients with osteoporosis or compromised fracture healing.

Bilobalide ameliorates ovariectomy-induced osteoporosis by influencing SIRT3/NF-κB axis in osteoclast and promoting M2 polarization in macrophages

Osteoporosis is a systemic disease with complex etiology and high incidence, resulting in a huge economic burden. For a long time, the search of new therapeutic pharmaceuticals has never stopped. Bone loss is related to the imbalance between bone resorption via osteoclast and bone formation via osteoblast. In recent years, the role of immunity and inflammation in the development of osteoporosis has attracted wide attention. Different cytokines, chemokines and endocrine factors regulate osteoclastogenesis by activating different macrophage subtypes, including pro-inflammatory M1 and anti-inflammatory M2. Bilobalide (Bil), an active Ginkgo biloba ingredient, has aroused our great interest because of its antioxidant and anti-inflammatory activities. In this study, we confirmed that Bil attenuated osteoclasts generation induced by receptor activator of nuclear factor- kappa B ligand (RANKL) through upregulating sirtuin 3 (SIRT3) and negatively regulating NF-κB signaling. Furthermore, Bil promotes M2 polarization of macrophages in a dose-dependent manner. In vivo studies provided evidence that Bil is able to improve bone density in ovariectomized (OVX) mice models. Based on the above results, we have the reason to believe that Bil has potential therapeutic value in osteoclast-mediated osteoporosis and may have the potential as a therapeutic drug in the future.

Nanocarrier-Assisted Delivery of Berberine Promotes Diabetic Alveolar Bone Regeneration by Scavenging ROS and Improving Mitochondrial Dysfunction

Purpose

Oxidative stress and mitochondrial dysfunction are potential contributors to the compromised tissue regeneration capacity of alveolar bone in diabetic patients. Berberine, an active plant alkaloid, exhibits multiple pharmacological effects including antioxidation, blood glucose- and blood lipid-lowering properties. However, it remains uncertain whether berberine can improve impaired osteogenesis in type 2 diabetes mellitus (T2DM), and its poor solubility and oral bioavailability also constrain its applications in bone regeneration. Thus, our study aimed to probe the effects of berberine on bone marrow stem cells (BMSCs) in a diabetic microenvironment, with a greater emphasis on developing a suitable nano-delivery system for berberine and assessing its capability to repair diabetic alveolar bone defects.

Methods

Firstly, BMSCs were exposed to berberine within a high glucose and palmitate (HG+PA) environment. Reactive oxygen species levels, mitochondrial membrane potential, ATP generation, cell apoptosis, and osteogenic potential were subsequently assessed. Next, we explored the regulatory mechanism of autophagy flux in the positive effects of berberine. Furthermore, a nanocarrier based on emulsion electrospinning for sustained local delivery of berberine (Ber@SF/PCL) was established. We assessed its capacity to enhance bone healing in the alveolar bone defect of T2DM rats through micro-computed tomography and histology analysis.

Results

Berberine treatment could inhibit reactive oxygen species overproduction, mitochondrial dysfunction, apoptosis, and improve osteogenesis differentiation by restoring autophagy flux under HG+PA conditions. Notably, Ber@SF/PCL electrospun nanofibrous membrane with excellent physicochemical properties and good biological safety had the potential to promote alveolar bone remodeling in T2DM rats.

Conclusion

Our study shed new lights into the protective role of berberine on BMSCs under T2DM microenvironment. Furthermore, berberine-loaded composite electrospun membrane may serve as a promising approach for regenerating alveolar bone in diabetic patients.

Sirtuin 3-activated superoxide dismutase 2 mediates fluoride-induced osteoblastic differentiation in vitro and in vivo by down-regulating reactive oxygen species

Skeletal fluorosis is a chronic metabolic bone disease caused by long-term excessive fluoride intake. Abnormal differentiation of osteoblasts plays an important role in disease progression. Research on the mechanism of fluoride-mediated bone differentiation is necessary for the prevention and treatment of skeletal fluorosis. In the present study, a rat model of fluorosis was established by exposing it to drinking water containing 50 mg/L F-. We found that fluoride promoted Runt-related transcription factor 2 (RUNX2) as well as superoxide dismutase 2 (SOD2) and sirtuin 3 (SIRT3) expression in osteoblasts of rat bone tissue. In vitro, we also found that 4 mg/L sodium fluoride promoted osteogenesis-related indicators as well as SOD2 and SIRT3 expression in MG-63 and Saos-2 cells. In addition, we unexpectedly discovered that fluoride suppressed the levels of reactive oxygen species (ROS) and mitochondrial reactive oxygen species (mtROS) in osteoblasts. When SOD2 or SIRT3 was inhibited in MG-63 cells, fluoride-decreased ROS and mtROS were alleviated, which in turn inhibited fluoride-promoted osteogenic differentiation. In conclusion, our results suggest that SIRT3/SOD2 mediates fluoride-promoted osteoblastic differentiation by down-regulating reactive oxygen species.

Irisin-Encapsulated Mitochondria-Targeted Biomimetic Nanotherapeutics for Alleviating Acute Kidney Injury

Acute kidney injury (AKI) is the sudden decrease in renal function that can be attributed to dysregulated reactive oxygen species (ROS) production and impaired mitochondrial function. Irisin, a type I membrane protein secreted by skeletal muscles in response to physical activity, has been reported to alleviate kidney damage through regulation of mitochondrial biogenesis and oxidative metabolism. In this study, a macrophage membrane-coated metal-organic framework (MCM@MOF) is developed as a nanocarrier for encapsulating irisin to overcome the inherent characteristics of irisin, including a short circulation time, limited kidney-targeting ability, and low membrane permeability. The engineered irisin-mediated biomimetic nanotherapeutics have extended circulation time and enhanced targeting capability toward injured kidneys due to the preservation of macrophage membrane proteins. The irisin-encapsulated biomimetic nanotherapeutics effectively mitigate acute ischemia-reperfusion injury by protecting mitochondrial function and modulating SOD2 levels in renal tubular epithelial cells. The present study provides novel insights to advance the development of irisin as a potential therapeutic approach for AKI.

STING regulates aging-related osteoporosis by mediating the Hk2-Vdac1 mitochondrial axis

Metabolic abnormalities and mild inflammation are hallmarks of aging and major driving factors for aging-related damage and bone metabolic diseases. Mitochondria are crucial links in energy metabolism and immune homeostasis regulation. Mitochondrial dysfunction is considered one of the pathogenic factors of aging-related osteoporosis, but its mechanism of action needs further research. Here, we demonstrated that the interaction between stimulator of interferon genes (STING)-mediated regulation of hexokinase 2 (Hk2)-voltage-dependent anion channel-1 (Vdac1) is a critical factor contributing to mitochondrial dysfunction and osteogenic abnormalities during aging. As the aging process progresses, factors related to aging cause an increase in STING expression, which disrupts the interaction between Hk2 and Vdac1. Dissociation of Hk2 from Vadc1 triggered the opening of the mitochondrial inner mitochondrial permeability transition pore (mPTP), leading to mitochondrial dysfunction and abnormal osteogenic differentiation, thereby disrupting bone homeostasis. In brief, this study demonstrates that STING acts as an intracellular metabolic Checkpoint, influencing mitochondrial function to promote the development of osteoporosis. These findings significantly enhance the development of STING-targeted treatments for aging-related osteoporosis.

NQO1 promotes osteogenesis and suppresses angiogenesis in DPSCs via MAPK pathway modulation

BACKGROUND

Influence on stem cells' angiogenesis and osteogenesis of NAD(P)H Quinone Dehydrogenase 1(NQO1) has been established, but its impact on dental pulp stem cells (DPSCs) is unexplored. An important strategy for the treatment of arteriosclerosis is to inhibit calcium deposition and to promote vascular repair and angiogenesis. This study investigated the function and mechanism of NQO1 on angiogenesis and osteogenesis of DPSCs, so as to provide a new ideal for the treatment of arteriosclerosis.

METHODS

Co-culture of human DPSCs and human umbilical vein endothelial cells (HUVECs) was used to detect the angiogenesis ability. Alkaline phosphatase (ALP) activity, alizarin red staining (ARS), and transplantation of HA/tricalcium phosphate with DPSCs were used to detect osteogenesis.

RESULTS

NQO1 suppressed in vitro tubule formation, migration, chemotaxis, and in vivo angiogenesis, as evidenced by reduced CD31 expression. It also enhanced ALP activity, ARS, DSPP expression and osteogenesis and boosted mitochondrial function in DPSCs. CoQ10, an electron transport chain activator, counteracted the effects of NQO1 knockdown on these processes. Additionally, NQO1 downregulated MAPK signaling, which was reversed by CoQ10 supplementation in DPSCs-NQO1sh.

CONCLUSIONS

NQO1 inhibited angiogenesis and promoted the osteogenesis of DPSCs by suppressing MAPK signaling pathways and enhancing mitochondrial respiration.

The multifaceted roles of mitochondria in osteoblasts: from energy production to mitochondrial-derived vesicle secretion

Mitochondria in osteoblasts have been demonstrated to play multiple crucial functions in bone formation from intracellular adenosine triphosphate production to extracellular secretion of mitochondrial components. The present review explores the current knowledge about mitochondrial biology in osteoblasts, including mitochondrial biogenesis, bioenergetics, oxidative stress generation, and dynamic changes in morphology. Special attention is given to recent findings, including mitochondrial donut formation in osteoblasts, which actively generates mitochondrial-derived vesicles (MDVs), followed by extracellular secretion of small mitochondria and MDVs. We also discuss the therapeutic effects of targeting osteoblast mitochondria, highlighting their potential applications in improving bone health.

Sirtuin 1 as a potential biomarker of undernutrition in the elderly: a narrative review

Undernutrition and inflammatory processes are predictors of early mortality in the elderly and require a rapid and accurate diagnosis. Currently, there are laboratory markers for assessing nutritional status, but new markers are still being sought. Recent studies suggest that sirtuin 1 (SIRT1) has the potential to be a marker for undernutrition. This article summarizes available studies on the association of SIRT1 and undernutrition in older people. Possible associations between SIRT1 and the aging process, inflammation, and undernutrition in the elderly have been described. The literature suggests that low SIRT1 levels in the blood of older people may not be associated with physiological aging processes, but with an increased risk of severe undernutrition associated with inflammation and systemic metabolic changes.

Obesity induced caveolin-1 impairs osteogenesis via activating mitophagy and inhibiting Sirt1 signaling

Obesity has become a major global health problem and the effect on bone formation has received increasing attention. However, the interaction between obesity and bone metabolism is complex and still not fully understood. Here, we show that caveolin-1 (Cav1), a membrane scaffold protein involved in regulating a variety of cellular processes, plays a key regulatory role as a bridge connecting obesity and bone metabolism. High-fat diet (HFD)-induced obese C57BL/6J mouse displayed a significant increase in Cav1 expression and lower osteogenic activity; In vitro treatment of osteoblastic MC3T3-E1 cells with 1 mM free fatty acids (FFA) significantly promoted Cav1 expression and PINK1/Parkin regulated mitophagy, but inhibited the expression of osteogenic marker genes. Conversely, reduced expression of the Cav1 gene prevented these effects. Both endogenous oxidative stress and Sirt1 pathway were also significantly reduced after Cav1 knockdown in FFA-treated cells. Finally, Cav1-Sirt1 docking and co-immunoprecipitation results showed that Cav1 interacted with Sirt1 and FFA enhanced the interaction. Taken together, these results suggest that obesity impairs bone development and formation through up-regulation of the Cav1 gene, which lead to inhibition of Sirt1/FOXO1 and Sirt1/PGC-1α signaling pathways through interacting with Sirt1 molecule, and an increase of mitophagy level.

Cellular Senescence: The Driving Force of Musculoskeletal Diseases

The aging of the world population is closely associated with an increased prevalence of musculoskeletal disorders, such as osteoporosis, sarcopenia, and osteoarthritis, due to common genetic, endocrine, and mechanical risk factors. These conditions are characterized by degeneration of bone, muscle, and cartilage tissue, resulting in an increased risk of fractures and reduced mobility. Importantly, a crucial role in the pathophysiology of these diseases has been proposed for cellular senescence, a state of irreversible cell cycle arrest induced by factors such as DNA damage, telomere shortening, and mitochondrial dysfunction. In addition, senescent cells secrete pro-inflammatory molecules, called senescence-associated secretory phenotype (SASP), which can alter tissue homeostasis and promote disease progression. Undoubtedly, targeting senescent cells and their secretory profiles could promote the development of integrated strategies, including regular exercise and a balanced diet or the use of senolytics and senomorphs, to improve the quality of life of the aging population. Therefore, our review aimed to highlight the role of cellular senescence in age-related musculoskeletal diseases, summarizing the main underlying mechanisms and potential anti-senescence strategies for the treatment of osteoporosis, sarcopenia, and osteoarthritis.

Sirt1: An Increasingly Interesting Molecule with a Potential Role in Bone Metabolism and Osteoporosis

Osteoporosis (OP) is a common metabolic bone disease characterized by low bone mass, decreased bone mineral density, and degradation of bone tissue microarchitecture. However, our understanding of the mechanisms of bone remodeling and factors affecting bone mass remains incomplete. Sirtuin1 (SIRT1) is a nicotinamide adenine dinucleotide-dependent deacetylase that regulates a variety of cellular metabolisms, including inflammation, tumorigenesis, and bone metabolism. Recent studies have emphasized the important role of SIRT1 in bone homeostasis. This article reviews the role of SIRT1 in bone metabolism and OP and also discusses therapeutic strategies and future research directions for targeting SIRT1.

α-Ketoglutarate prevents hyperlipidemia-induced fatty liver mitochondrial dysfunction and oxidative stress by activating the AMPK-pgc-1α/Nrf2 pathway

α-Ketoglutarate (AKG), a crucial intermediate in the tricarboxylic acid cycle, has been demonstrated to mitigate hyperlipidemia-induced dyslipidemia and endothelial damage. While hyperlipidemia stands as a major trigger for non-alcoholic fatty liver disease, the protection of AKG on hyperlipidemia-induced hepatic metabolic disorders remains underexplored. This study aims to investigate the potential protective effects and mechanisms of AKG against hepatic lipid metabolic disorders caused by acute hyperlipidemia. Our observations indicate that AKG effectively alleviates hepatic lipid accumulation, mitochondrial dysfunction, and loss of redox homeostasis in P407-induced hyperlipidemia mice, as well as in palmitate-injured HepG2 cells and primary hepatocytes. Mechanistic insights reveal that the preventive effects are mediated by activating the AMPK-PGC-1α/Nrf2 pathway. In conclusion, our findings shed light on the role and mechanism of AKG in ameliorating abnormal lipid metabolic disorders in hyperlipidemia-induced fatty liver, suggesting that AKG, an endogenous mitochondrial nutrient, holds promising potential for addressing hyperlipidemia-induced fatty liver conditions.

Capsaicin attenuates Porphyromonas gingivalis-suppressed osteogenesis of periodontal ligament stem cells via regulating mitochondrial function and activating PI3K/AKT/mTOR pathway

BACKGROUND AND OBJECTIVE

Prevention of periodontal bone resorption triggered by Porphyromonas gingivalis (P. gingivalis) is crucial for dental stability. Capsaicin, known as the pungent ingredient of chili peppers, can activate key signaling molecules involved in osteogenic process. However, the effect of capsaicin on osteogenesis of periodontal ligament stem cells (PDLSCs) under inflammation remains elusive.

METHODS

P. gingivalis culture suspension was added to mimic the inflammatory status after capsaicin pretreatment. The effects of capsaicin on the osteogenesis of PDLSCs, as well as mitochondrial morphology, Ca2+ level, reactive oxygen species (ROS), mitochondrial membrane potential (MMP), and osteogenesis-regulated protein expression levels were analyzed. Furthermore, a mouse experimental periodontitis model was established to evaluate the effect of capsaicin on alveolar bone resorption and the expression of osteogenesis-related proteins.

RESULTS

Under P. gingivalis stimulation, capsaicin increased osteogenesis of PDLSCs. Not surprisingly, capsaicin rescued the damage to mitochondrial morphology, decreased the concentration of intracellular Ca2+ and ROS, enhanced MMP and activated phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway. The in vivo results showed that capsaicin significantly attenuated alveolar bone loss and augmented the expression of bone associated proteins.

CONCLUSION

Capsaicin increases osteogenesis of PDLSCs under inflammation and reduces alveolar bone resorption in mouse experimental periodontitis.

Fibroblast growth factor 23 inhibition attenuates steroid-induced osteonecrosis of the femoral head through pyroptosis

Steroid-induced osteonecrosis of the femoral head (SONFH) is the predominant cause of non-traumatic osteonecrosis of the femoral head (ONFH). Impaired blood supply and reduced osteogenic activity of the femoral head are the key pathogenic mechanisms of SONFH. Fibroblast growth factor 23 (FGF23) levels are not only a biomarker for early vascular lesions caused by abnormal mineral metabolism, but can also act directly on the peripheral vascular system, leading to vascular pathology. The aim of this study was to observe the role of FGF23 on bone microarchitecture and vascular endothelium, and to investigate activation of pyroptosis in SONFH. Lipopolysaccharide (LPS) combined with methylprednisolone (MPS) was applied for SONFH mouse models, and adenovirus was used to increase or decrease the level of FGF23. Micro-CT and histopathological staining were used to observe the structure of the femoral head, and immunohistochemical staining was used to observe the vascular density. The cells were further cultured in vitro and placed in a hypoxic environment for 12 h to simulate the microenvironment of vascular injury during SONFH. The effect of FGF23 on osteogenic differentiation was evaluated using alkaline phosphatase staining, alizarin red S staining and expression of bone formation-related proteins. Matrigel tube formation assay in vitro and immunofluorescence were used to detect the ability of FGF23 to affect endothelial cell angiogenesis. Steroids activated the pyroptosis signaling pathway, promoted the secretion of inflammatory factors in SONFH models, led to vascular endothelial dysfunction and damaged the femoral head structure. In addition, FGF23 inhibited the HUVECs angiogenesis and BMSCs osteogenic differentiation. FGF23 silencing attenuated steroid-induced osteonecrosis of the femoral head by inhibiting the pyroptosis signaling pathway, and promoting osteogenic differentiation of BMSCs and angiogenesis of HUVECs in vitro.

Application of Antioxidant Compounds in Bone Defect Repair

Bone defects caused by trauma, tumor resection, and infections are significant clinical challenges. Excessive reactive oxygen species (ROS) usually accumulate in the defect area, which may impair the function of cells involved in bone formation, posing a serious challenge for bone repair. Due to the potent ROS scavenging ability, as well as potential anti-inflammatory and immunomodulatory activities, antioxidants play an indispensable role in the maintenance and protection of bone health and have gained increasing attention in recent years. This narrative review aims to give an overview of the main research directions on the application of antioxidant compounds in bone defect repair over the past decade. In addition, the positive effects of various antioxidants and their biomaterial delivery systems in bone repair are summarized to provide new insights for exploring antioxidant-based strategies for bone defect repair.

Investigating the influence of titanium particle size and concentration on osteogenic response of human osteoblasts - in vitro study

Purpose

The purpose of this study was to investigate the correlation between the size and concentration of titanium particles and the osteogenic response of human osteoblasts (HOB).

Materials and Methods

Different concentrations of titanium dioxide nano- and micro-particles were prepared and their biocompatibility on HOBs was analyzed using XTT assay. The changes in the actin cytoskeletal organization were studied by confocal laser scanning microscopy. The generation of intracellular reactive oxygen species (ROS) by HOBs after exposure to titanium dioxide particles was analyzed using ROS assay. Besides, the osteogenic potential represented by alkaline phosphatase activity, osteoprotegerin, macrophage colony stimulating factor levels, and biomineralization were analyzed.

Results

Short-term interaction of titanium dioxide nano- and micro-particles did not induce toxicity to HOBs. However, cells treated with 100 μg/mL titanium dioxide nano- and micro-particles demonstrated higher ROS generation compared to control. Besides, cells treated with 100 μg/mL titanium dioxide nanoparticles showed higher alkaline phosphatase activity, osteoprotegerin, macrophage colony stimulating factor levels and biomineralization compared to titanium dioxide microparticles.

Conclusion

Collectively, the study found titanium dioxide nanoparticles to be more biocompatible than microparticles providing an insight into the capability of nanostructures in supporting osteoblast differentiation and its plausibility in biomedical applications.

Extracellular Vesicles Derived from Neutrophils Accelerate Bone Regeneration by Promoting Osteogenic Differentiation of BMSCs

The reconstruction of bone defects has been associated with severe challenges worldwide. Nowadays, bone marrow mesenchymal stem cell (BMSC)-based cell sheets have rendered this approach a promising way to facilitate osteogenic regeneration in vivo. Extracellular vesicles (EVs) play an essential role in intercellular communication and execution of various biological functions and are often employed as an ideal natural endogenous nanomedicine for restoring the structure and functions of damaged tissues. The perception of polymorphonuclear leukocytes (neutrophils, PMNs) as indiscriminate killer cells is gradually changing, with new evidence suggesting a role for these cells in tissue repair and regeneration, particularly in the context of bone healing. However, the role of EVs derived from PMNs (PMN-EVs) in bone regeneration remains largely unknown, with limited research being conducted on this aspect. In the current study, we investigated the effects of PMN-EVs on BMSCs and the underlying molecular mechanisms as well as the potential application of PMN-EVs in bone regeneration. Toward this end, BMSC-based cell sheets with integrated PMN-EVs (BS@PMN-EVs) were developed for bone defect regeneration. PMN-EVs were found to significantly enhance the proliferation and osteogenic differentiation of BMSCs in vitro. Furthermore, BS@PMN-EVs were found to significantly accelerate bone regeneration in vivo by enhancing the maturation of the newly formed bone in rat calvarial defects; this is likely attributable to the effect of PMN-EVs in promoting the expression of key osteogenic proteins such as SOD2 and GJA1 in BMSCs. In conclusion, our findings demonstrate the crucial role of PMN-EVs in promoting the osteogenic differentiation of BMSCs during bone regeneration. Furthermore, this study proposes a novel strategy for enhancing bone repair and regeneration via the integration of PMN-EVs with BMSC-based cell sheets.

Diacylglycerol O-acyltransferase (DGAT) isoforms play a role in peridroplet mitochondrial fatty acid metabolism in bovine liver

Hepatocellular lipid accumulation characterizes fatty liver in dairy cows. Lipid droplets (LD), specialized organelles that store lipids and maintain cellular lipid homeostasis, are responsible for the ectopic storage of lipids associated with several metabolic disorders. In recent years, non-ruminant studies have reported that LD-mitochondria interactions play an important role in lipid metabolism. Due to the role of diacylglycerol acyltransferase isoforms (DGAT1 and DGAT2) in LD synthesis, we explored mechanisms of mitochondrial fatty acid transport in ketotic cows using liver biopsies and isolated primary hepatocytes. Compared with healthy cows, cows with fatty liver had massive accumulation of LD and high protein expression of the triglyceride (TAG) synthesis-related enzymes DGAT1 and DGAT2, LD synthesis-related proteins perilipin 2 (PLIN2) and perilipin 5 (PLIN5), and the mitochondrial fragmentation-related proteins dynamin-related protein 1 (DRP1) and fission 1 (FIS1). In contrast, factors associated with fatty acid oxidation, mitochondrial fusion and mitochondrial electron transport chain complex were lower compared with those in the healthy cows. In addition, transmission electron microscopy revealed significant contacts between LD-mitochondria in liver tissue from cows with fatty liver. Compared with isolated cytoplasmic mitochondria, expression of carnitine palmitoyl transferase 1A (CPT1A) and DRP1 was lower, but mitofusin 2 (MFN2) and mitochondrial electron transport chain complex was greater in isolated peridroplet mitochondria from hepatic tissue of cows with fatty liver. In vitro data indicated that exogenous free fatty acids (FFA) induced hepatocyte LD synthesis and mitochondrial dynamics consistent with in vivo results. Furthermore, DGAT2 inhibitor treatment attenuated the FFA-induced upregulation of PLIN2 and PLIN5 and rescued the impairment of mitochondrial dynamics. Inhibition of DGAT2 also restored mitochondrial membrane potential and reduced hepatocyte reactive oxygen species production. The present in vivo and in vitro results indicated there are functional differences among different types of mitochondria in the liver tissue of dairy cows with ketosis. Activity of DGAT2 may play a key role in maintaining liver mitochondrial function and lipid homeostasis in dairy cows during the transition period.

Current understanding of the pathogenesis of placenta accreta spectrum disorder with focus on mitochondrial function

AIM

The refinement of assisted reproductive technology, including the development of cryopreservation techniques (vitrification) and ovarian stimulation protocols, makes frozen embryo transfer (FET) an alternative to fresh ET and has contributed to the success of assisted reproductive technology. Compared with fresh ET cycles, FET cycles were associated with better in vitro fertilization outcomes; however, the occurrence of pregnancy-induced hypertension, preeclampsia, and placenta accreta spectrum (PAS) was higher in FET cycles. PAS has been increasing steadily in incidence as a life-threatening condition along with cesarean rates worldwide. In this review, we summarize the current understanding of the pathogenesis of PAS and discuss future research directions.

METHODS

A literature search was performed in the PubMed and Google Scholar databases.

RESULTS

Risk factors associated with PAS incidence include a primary defect of the decidua basalis or scar dehiscence, aberrant vascular remodeling, and abnormally invasive trophoblasts, or a combination thereof. Freezing, thawing, and hormone replacement manipulations have been shown to affect multiple cellular pathways, including cell proliferation, invasion, epithelial-to-mesenchymal transition (EMT), and mitochondrial function. Molecules involved in abnormal migration and EMT of extravillous trophoblast cells are beginning to be identified in PAS placentas. Many of these molecules were also found to be involved in mitochondrial biogenesis and dynamics.

CONCLUSION

The etiology of PAS may be a multifactorial genesis with intrinsic predisposition (e.g., placental abnormalities) and certain environmental factors (e.g., defective decidua) as triggers for its development. A distinctive feature of this review is its focus on the potential factors linking mitochondrial function to PAS development.

SIRT3: A Potential Target of Different Types of Osteoporosis

Osteoporosis (OP) is a common age-related disease. OP is mainly a decrease in bone density and mass caused by the destruction of bone microstructure, which leads to an increase in bone fragility. SIRT3 is a mitochondrial deacetylase that plays critical roles in mitochondrial homeostasis, metabolic regulation, gene transcription, stress response, and gene stability. Studies have shown that the higher expression levels of SIRT3 are associated with decreased levels of oxidative stress in the body and may play important roles in the prevention of age-related diseases. SIRTs can enhance the osteogenic potential and osteoblastic activity of bone marrow mesenchymal stromal cells not only by enhancing PGC-1α, FOXO3, SOD2, and oxidative phosphorylation, but also by anti-aging and reducing mitochondrial autophagy. SIRT3 is able to upregulate antioxidant enzymes to exert an inhibitory effect on osteoclasts, however, it has been shown that the inflammatory cascade response can in turn increase SIRT3 and inhibit osteoclast differentiation through the AMPK-PGC-1β pathway. SIRT3 plays an important role in different types of osteoporosis by affecting osteoblasts, osteoclasts, and bone marrow mesenchymal cells. In this review, we discuss the classification and physiological functions of SIRTs, the effects of SIRT3 on OCs osteoblasts, and BMSCs, and the roles and mechanisms of SIRT3 in different types of OP, such as diabetic OP, glucocorticoid-induced OP, postmenopausal OP, and senile OP.

FNDC5 prevents oxidative stress and neuronal apoptosis after traumatic brain injury through SIRT3-dependent regulation of mitochondrial quality control

Mitochondrial dysfunction and oxidative stress are important mechanisms for secondary injury after traumatic brain injury (TBI), which result in progressive pathophysiological exacerbation. Although the Fibronectin type III domain-containing 5 (FNDC5) was reported to repress oxidative stress by retaining mitochondrial biogenesis and dynamics, its possible role in the secondary injury after TBI remain obscure. In present study, we observed that the level of serum irisin (the cleavage product of FNDC5) significantly correlated with the neurological outcomes of TBI patients. Knockout of FNDC5 increased the lesion volume and exacerbated apoptosis and neurological deficits after TBI in mice, while FNDC5 overexpression yielded a neuroprotective effect. Moreover, FNDC5 deficiency disrupted mitochondrial dynamics and function. Activation of Sirtuin 3 (SIRT3) alleviated FNDC5 deficiency-induced disruption of mitochondrial dynamics and bioenergetics. In neuron-specific SIRT3 knockout mice, FNDC5 failed to attenuate TBI-induced mitochondrial damage and brain injuries. Mechanically, FNDC5 deficiency led to reduced SIRT3 expression via enhanced ubiquitin degradation of transcription factor Nuclear factor erythroid 2-related factor 2 (NRF2), which contributed to the hyperacetylation and inactivation of key regulatory proteins of mitochondrial dynamics and function, including OPA1 and SOD2. Finally, engineered RVG29-conjugated nanoparticles were generated to selectively and efficiently deliver irisin to the brain of mice, which yielded a satisfactory curative effect against TBI. In conclusion, FNDC5/irisin exerts a protective role against acute brain injury by promoting SIRT3-dependent mitochondrial quality control and thus represents a potential target for neuroprotection after TBI.

Metformin induction of heat shock factor 1 activation and the mitochondrial unfolded protein response alleviate cardiac remodeling in spontaneously hypertensive rats

Heart failure and cardiac remodeling are both characterized by mitochondrial dysfunction. Healthy mitochondria are required for adequate contractile activity and appropriate regulation of cell survival. In the mammalian heart, enhancement of the mitochondrial unfolded protein response (UPRmt) is cardioprotective under pressure overload conditions. We explored the UPRmt and the underlying regulatory mechanism in terms of hypertension-induced cardiac remodeling and the cardioprotective effect of metformin. Male spontaneously hypertensive rats and angiotensin II-treated neonatal rat cardiomyocytes were used to induce cardiac hypertrophy. The results showed that hypertension induced the formation of aberrant mitochondria, characterized by a reduced mtDNA/nDNA ratio and swelling, as well as lower levels of mitochondrial complexes I to V and inhibition of the expression of one protein subunit of each of complexes I to IV. Such changes eventually enlarged cardiomyocytes and increased cardiac fibrosis. Metformin treatment increased the mtDNA/nDNA ratio and regulated the UPRmt, as indicated by increased expression of activating transcription factor 5, Lon protease 1, and heat shock protein 60, and decreased expression of C/EBP homologous protein. Thus, metformin improved mitochondrial ultrastructure and function in spontaneously hypertensive rats. In vitro analyses revealed that metformin reduced the high levels of angiotensin II-induced mitochondrial reactive oxygen species in such animals and stimulated nuclear translocation of heat shock factor 1 (HSF1). Moreover, HSF1 small-interfering RNA reduced the metformin-mediated improvements in mitochondrial morphology and the UPRmt by suppressing hypertrophic signals and cardiomyocyte apoptosis. These results suggest that HSF1/UPRmt signaling contributes to the beneficial effects of metformin. Metformin-mediated targeting of mitochondrial protein homeostasis and modulation of HSF1 levels have potential therapeutic implications in terms of cardiac remodeling.

Carnosol alleviates sepsis-induced pulmonary endothelial barrier dysfunction by targeting nuclear factor erythroid2-related factor 2/sirtuin-3 signaling pathway to attenuate oxidative damage

Excessive reactive oxygen species production during acute lung injury (ALI) will aggravate the inflammatory process and endothelial barrier dysfunction. Carnosol is a natural phenolic diterpene with antioxidant and anti-inflammatory properties, but its role in treating sepsis-induced ALI remains unclear. This study aims to explore the protective effects and underlying mechanisms of carnosol in sepsis-induced ALI. C57BL/6 mouse were preconditioned with carnosol for 1 h, then the model of lipopolysaccharide (LPS)-induced sepsis was established. The degree of pulmonary edema, oxidative stress, and inflammation were detected. Endothelial barrier function was evaluated by apoptosis and cell junctions. In vitro, Mito Tracker Green probe, JC-1 staining, and MitoSOX staining were conducted to investigate the effect of carnosol on mitochondria. Finally, we investigated the role of nuclear factor-erythroid 2-related factor (Nrf2)/sirtuin-3 (SIRT3) in carnosol against ALI. Carnosol alleviated LPS-induced pulmonary oxidative stress and inflammation by inhibiting excess mitochondrial reactive oxygen species production and maintaining mitochondrial homeostasis. Furthermore, carnosol also attenuated LPS-induced endothelial cell barrier damage by reducing vascular endothelial cell apoptosis and restoring occludin, ZO-1, and vascular endothelial-Cadherin expression in vitro and in vivo. In addition, carnosol increased Nrf2 nuclear translocation to promote SIRT3 expression. The protective effects of carnosol on ALI were largely abolished by inhibition of Nrf2/SIRT3. Our study has provided the first evidence that the Nrf2/SIRT3 pathway is a protective target of the endothelial barrier in ALI, and carnosol can serve as a potential therapeutic candidate for ALI by utilizing its ability to target this pathway.

Superoxide dismutase 2 scavenges ROS to promote osteogenic differentiation of human periodontal ligament stem cells by regulating Smad3 in alveolar bone-defective rats

BACKGROUND

Osteogenic differentiation of human periodontal ligament stem cells (hPDLSCs) is an essential event in alveolar bone regeneration. Oxidative stress may be the main inhibiting factor of hPDLSC osteogenesis. Superoxide dismutase 2 (SOD2) is a key antioxidant enzyme, but its effect on hPDLSC osteogenic differentiation is unclear.

METHODS

Several surface markers were detected by flow cytometry, and the differentiation potential of hPDLSCs was validated by alkaline phosphatase (ALP), Alizarin Red S, and Oil Red O staining. Osteogenic indicators of hPDLSCs were detected by real-time quantitative polymerase chain reaction (RT-qPCR), Western blotting, and ALP staining. Furthermore, alveolar bone defect rat models were analyzed through micro-CT, hematoxylin and eosin, and Masson staining. The intracellular reactive oxygen species (ROS) level was evaluated by a ROS assay kit. Finally, the expression of SOD2, Smad3, and p-Smad3 in hPDLSCs was detected by RT-qPCR and Western blotting (WB).

RESULTS

SOD2 positively regulated the gene and protein expressions of ALP, BMP6, and RUNX2 in hPDLSCs (p < 0.05). Ideal bone formation and continuous cortical bone were obtained by transplanting LV-SOD2 hPDLSCs (lentivirus vector for overexpressing SOD2 in hPDLSCs) in vivo. Exogenous H2O2 downregulated osteogenic indicators (ALP, BMP6, RUNX2) in hPDLSCs (p < 0.05); this was reversed by overexpression of SOD2. WB results showed that the Smad3 and p-Smad3 signaling pathways participated in the osteogenic process of SOD2 in hPDLSCs.

CONCLUSION

SOD2 positively regulated hPDLSC osteogenic differentiation in vitro and in vivo. Mechanistically, SOD2 promotes hPDLSC osteogenic differentiation by regulating the phosphorylation of Smad3 to scavenge ROS. This work provides a theoretical basis for the treatment of alveolar bone regeneration.

Defining the Most Potent Osteoinductive Culture Conditions for MC3T3-E1 Cells Reveals No Implication of Oxidative Stress or Energy Metabolism

The MC3T3-E1 preosteoblastic cell line is widely utilised as a reliable in vitro system to assess bone formation. However, the experimental growth conditions for these cells hugely diverge, and, particularly, the osteogenic medium (OSM)'s composition varies in research studies. Therefore, we aimed to define the ideal culture conditions for MC3T3-E1 subclone 4 cells with regard to their mineralization capacity and explore if oxidative stress or the cellular metabolism processes are implicated. Cells were treated with nine different combinations of long-lasting ascorbate (Asc) and β-glycerophosphate (βGP), and osteogenesis/calcification was evaluated at three different time-points by qPCR, Western blotting, and bone nodule staining. Key molecules of the oxidative and metabolic pathways were also assessed. It was found that sufficient mineral deposition was achieved only in the 150 μg.mL-1/2 mM Asc/βGP combination on day 21 in OSM, and this was supported by Runx2, Alpl, Bglap, and Col1a1 expression level increases. NOX2 and SOD2 as well as PGC1α and Tfam were also monitored as indicators of redox and metabolic processes, respectively, where no differences were observed. Elevation in OCN protein levels and ALP activity showed that mineralisation comes as a result of these differences. This work defines the most appropriate culture conditions for MC3T3-E1 cells and could be used by other research laboratories in this field.

TMEM135 maintains the equilibrium of osteogenesis and adipogenesis by regulating mitochondrial dynamics

BACKGROUND

Disturbance in the differentiation process of bone marrow mesenchymal stem cells (BMSCs) leads to osteoporosis. Mitochondrial dynamics plays a pivotal role in the metabolism and differentiation of BMSCs. However, the mechanisms underlying mitochondrial dynamics and their impact on the differentiation equilibrium of BMSCs remain unclear.

METHODS

We investigated the mitochondrial morphology and markers related to mitochondrial dynamics during BMSCs osteogenic and adipogenic differentiation. Bioinformatics was used to screen potential genes regulating BMSCs differentiation through mitochondrial dynamics. Subsequently, we evaluated the impact of Transmembrane protein 135 (TMEM135) deficiency on bone homeostasis by comparing Tmem135 knockout mice with their littermates. The mechanism of TMEM135 in mitochondrial dynamics and BMSCs differentiation was also investigated in vivo and in vitro.

RESULTS

Distinct changes in mitochondrial morphology were observed between osteogenic and adipogenic differentiation of BMSCs, manifesting as fission in the late stage of osteogenesis and fusion in adipogenesis. Additionally, we revealed that TMEM135, a modulator of mitochondrial dynamics, played a functional role in regulating the equilibrium between adipogenesis and osteogenesis. The TMEM135 deficiency impaired mitochondrial fission and disrupted crucial mitochondrial energy metabolism during osteogenesis. Tmem135 knockout mice showed osteoporotic phenotype, characterized by reduced osteogenesis and increased adipogenesis. Mechanistically, TMEM135 maintained intracellular calcium ion homeostasis and facilitated the dephosphorylation of dynamic-related protein 1 at Serine 637 in BMSCs.

CONCLUSIONS

Our findings underscore the significant role of TMEM135 as a modulator in orchestrating the differentiation trajectory of BMSCs and promoting a shift in mitochondrial dynamics toward fission. This ultimately contributes to the osteogenesis process. This work has provided promising biological targets for the treatment of osteoporosis.

Acetylated Histone Modifications: Intersection of Diabetes and Atherosclerosis

ABSTRACT

Worldwide, type 2 diabetes is predominant form of diabetes, and it is mainly affected by the environment. Furthermore, the offspring of patients with type 2 diabetes and metabolic disorder syndrome may have a higher risk of diabetes and cardiovascular disease, which indicates that the environmental impact on diabetes prevalence can be transmitted across generations. In the process of diabetes onset and intergenerational transmission, the genetic structure of the individual is not directly changed but is regulated by epigenetics. In this process, genes or histones are modified, resulting in selective expression of proteins. This modification will affect not only the onset of diabetes but also the related onset of atherosclerosis. Acetylation and deacetylation may be important regulatory factors for the above lesions. Therefore, in this review, based on the whole process of atherosclerosis evolution, we explored the possible existence of acetylation/deacetylation caused by diabetes. However, because of the lack of atherosclerosis-related acetylation studies directly based on diabetic models, we also used a small number of experiments involving nondiabetic models of related molecular mechanisms.

Identification and analysis of mitochondria-related central genes in steroid-induced osteonecrosis of the femoral head, along with drug prediction

Purpose

Steroid-induced osteonecrosis of the femoral head (SONFH) is a refractory orthopedic hip joint disease that primarily affects middle-aged and young individuals. SONFH may be caused by ischemia and hypoxia of the femoral head, where mitochondria play a crucial role in oxidative reactions. Currently, there is limited literature on whether mitochondria are involved in the progression of SONFH. Here, we aim to identify and validate key potential mitochondrial-related genes in SONFH through bioinformatics analysis. This study aims to provide initial evidence that mitochondria play a role in the progression of SONFH and further elucidate the mechanisms of mitochondria in SONFH.

Methods

The GSE123568 mRNA expression profile dataset includes 10 non-SONFH (non-steroid-induced osteonecrosis of the femoral head) samples and 30 SONFH samples. The GSE74089 mRNA expression profile dataset includes 4 healthy samples and 4 samples with ischemic necrosis of the femoral head. Both datasets were downloaded from the Gene Expression Omnibus (GEO) database. The mitochondrial-related genes are derived from MitoCarta3.0, which includes data for all 1136 human genes with high confidence in mitochondrial localization based on integrated proteomics, computational, and microscopy approaches. By intersecting the GSE123568 and GSE74089 datasets with a set of mitochondrial-related genes, we screened for mitochondrial-related genes involved in SONFH. Subsequently, we used the good Samples Genes method in R language to remove outlier genes and samples in the GSE123568 dataset. We further used WGCNA to construct a scale-free co-expression network and selected the hub gene set with the highest connectivity. We then intersected this gene set with the previously identified mitochondrial-related genes to select the genes with the highest correlation. A total of 7 mitochondrial-related genes were selected. Next, we performed Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis on the selected mitochondrial-related genes using R software. Furthermore, we performed protein network analysis on the differentially expressed proteins encoded by the mitochondrial genes using STRING. We used the GSEA software to group the genes within the gene set in the GSE123568 dataset based on their coordinated changes and evaluate their impact on phenotype changes. Subsequently, we grouped the samples based on the 7 selected mitochondrial-related genes using R software and observed the differences in immune cell infiltration between the groups. Finally, we evaluated the prognostic significance of these features in the two datasets, consisting of a total of 48 samples, by integrating disease status and the 7 gene features using the cox method in the survival R package. We performed ROC analysis using the roc function in the pROC package and evaluated the AUC and confidence intervals using the ci function to obtain the final AUC results.

Results

Identification and analysis of 7 intersecting DEGs (differentially expressed genes) were obtained among peripheral blood, cartilage samples, hub genes, and mitochondrial-related genes. These 7 DEGs include FTH1, LACTB, PDK3, RAB5IF, SOD2, and SQOR, all of which are upregulated genes with no intersection in the downregulated gene set. Subsequently, GO and KEGG pathway enrichment analysis revealed that the upregulated DEGs are primarily involved in processes such as oxidative stress, release of cytochrome C from mitochondria, negative regulation of intrinsic apoptotic signaling pathway, cell apoptosis, mitochondrial metabolism, p53 signaling pathway, and NK cell-mediated cytotoxicity. GSEA also revealed enriched pathways associated with hub genes. Finally, the diagnostic value of these key genes for hormone-related ischemic necrosis of the femoral head (SONFH) was confirmed using ROC curves.

Conclusion

BID, FTH1, LACTB, PDK3, RAB5IF, SOD2, and SQOR may serve as potential diagnostic mitochondrial-related biomarkers for SONFH. Additionally, they hold research value in investigating the involvement of mitochondria in the pathogenesis of ischemic necrosis of the femoral head.

Mitochondrial dysfunction and therapeutic perspectives in osteoporosis

Osteoporosis (OP) is a systemic skeletal disorder characterized by reduced bone mass and structural deterioration of bone tissue, resulting in heightened vulnerability to fractures due to increased bone fragility. This condition primarily arises from an imbalance between the processes of bone resorption and formation. Mitochondrial dysfunction has been reported to potentially constitute one of the most crucial mechanisms influencing the pathogenesis of osteoporosis. In essence, mitochondria play a crucial role in maintaining the delicate equilibrium between bone formation and resorption, thereby ensuring optimal skeletal health. Nevertheless, disruption of this delicate balance can arise as a consequence of mitochondrial dysfunction. In dysfunctional mitochondria, the mitochondrial electron transport chain (ETC) becomes uncoupled, resulting in reduced ATP synthesis and increased generation of reactive oxygen species (ROS). Reinforcement of mitochondrial dysfunction is further exacerbated by the accumulation of aberrant mitochondria. In this review, we investigated and analyzed the correlation between mitochondrial dysfunction, encompassing mitochondrial DNA (mtDNA) alterations, oxidative phosphorylation (OXPHOS) impairment, mitophagy dysregulation, defects in mitochondrial biogenesis and dynamics, as well as excessive ROS accumulation, with regards to OP (Figure 1). Furthermore, we explore prospective strategies currently available for modulating mitochondria to ameliorate osteoporosis. Undoubtedly, certain therapeutic strategies still require further investigation to ensure their safety and efficacy as clinical treatments. However, from a mitochondrial perspective, the potential for establishing effective and safe therapeutic approaches for osteoporosis appears promising.

Mangiferin attenuates osteoporosis by inhibiting osteoblastic ferroptosis through Keap1/Nrf2/SLC7A11/GPX4 pathway

BACKGROUND

Ferroptosis is a crucial contributor to impaired osteoblast function in osteoporosis. Mangiferin, a xanthonoid glucoside isolated from mangoes, exhibits anti-osteoporosis effects. However, its potential mechanism is not fully understood.

PURPOSE

This study explores the potencies of mangiferin on osteoblastic ferroptosis and deciphers its direct target in the context of solute carrier family 7-member 11 (SLC7A11)/glutathione peroxidases 4 (GPX4) pathway.

METHODS

In vivo models include bilateral ovariectomy induced osteoporosis mice, iron-dextran induced iron-overloaded mice, and nuclear factor-erythroid 2-related factor 2 (Nrf2)-knockout mice. Mice are orally administrated mangiferin (10, 50 or 100 mg.kg-1.d-1) for 12 weeks. In vitro osteoblast models include iron-dextran induced iron-overloaded cells, erastin induced ferroptosis cells, and gene knockout cells. RNA sequencing is applied for investigating the underlying mechanisms. The direct target of mangiferin is studied using a cellular thermal shift assay, silico docking, and surface plasmon resonance.

RESULTS

Mangiferin promotes bone formation and inhibits ferroptosis in vivo models (osteoporosis mice, iron-overloaded mice) and in vitro models (ferroptosis osteoblast, iron-overloaded osteoblasts). Mechanismly, mangiferin directly binds to the kelch-like ECH-associated protein 1 (Keap1) and activates the downstream Nrf2/SLC7A11/GPX4 pathway in both the in vivo and in vitro models. Mangiferin failed to restore the osteoporosis and ferroptosis in Nrf2-knockout mice. Silencing Nrf2, SLC7A11 or GPX4 abolished the anti-ferroptosis effect of mangiferin in erastin-induced cells. Addition of the ferroptosis agonist RSL-3 also blocked the protective effects of mangiferin on iron-overloaded cells. Furthermore, mangiferin had better effects on osteogenesis than the ferroptosis inhibitor (ferrostatin-1) and the Nrf2 agonists (sulforaphane, dimethyl fumarate, and bardoxolone).

CONCLUSIONS

We identify for the first time mangiferin as a ferroptosis inhibitor and a direct Keap1 conjugator that promotes bone formation and alleviates osteoporosis. This work also provides a potentially practical pharmacological approach for treating ferroptosis-driven diseases.

Dose-dependent exposure to indoxyl sulfate alters AHR signaling, sirtuins gene expression, oxidative DNA damage, and bone mineral status in rats

Indoxyl sulfate (IS), an agonist of aryl hydrocarbon receptors (AhR), can accumulate in patients with chronic kidney disease, but its direct effect on bone is not clear. The present study investigated the effect of chronic exposure to low (100 mg/kg b.w.; 100 IS) and high (200 mg/kg b.w.; 200 IS) dose of IS on bone AhR pathway, sirtuins (SIRTs) expression, oxidative DNA damage and bone mineral status in Wistar rats. The accumulation of IS was observed only in trabecular bone tissue in both doses. The differences were observed in the bone parameters, depending on the applied IS dose. The exposure to 100 IS increased AhR repressor (AhRR)-CYP1A2 gene expression, which was associated with SIRT-1, SIRT-3 and SIRT-7 expression. At the low dose group, the oxidative DNA damage marker was unchanged in the bone samples, and it was inversely related to the abovementioned SIRTs expression. In contrast, the exposure to 200 IS reduced the expression of AhRR, CYP1A, SIRT-3 and SIRT-7 genes compared to 100 IS. The level of oxidative DNA damage was higher in trabecular bone in 200 IS group. Femoral bone mineral density was decreased, and inverse relations were noticed between the level of trabecular oxidative DNA damage and parameters of bone mineral status. In conclusion, IS modulates AhR-depending signaling affecting SIRTs expression, oxidative DNA damage and bone mineral status in a dose dependent manner.

From drugs to biomaterials: a review of emerging therapeutic strategies for intervertebral disc inflammation

Chronic low back pain (LBP) is an increasingly prevalent issue, especially among aging populations. A major underlying cause of LBP is intervertebral disc degeneration (IDD), often triggered by intervertebral disc (IVD) inflammation. Inflammation of the IVD is divided into Septic and Aseptic inflammation. Conservative therapy and surgical treatment often fail to address the root cause of IDD. Recent advances in the treatment of IVD infection and inflammation range from antibiotics and small-molecule drugs to cellular therapies, biological agents, and innovative biomaterials. This review sheds light on the complex mechanisms of IVD inflammation and physiological and biochemical processes of IDD. Furthermore, it provides an overview of recent research developments in this area, intending to identify novel therapeutic targets and guide future clinical strategies for effectively treating IVD-related conditions.

Nicotinamide mononucleotide attenuates airway epithelial barrier dysfunction via inhibiting SIRT3 SUMOylation in asthma

Nicotinamide adenine dinucleotide (NAD+) is an essential element in cellular metabolism that regulates fundamental biological processes. Growing evidence suggests that a decline in NAD+ is a common pathological factor in various diseases and aging. However, its role in airway epithelial barrier function in response to asthma remains underexplored. The current study aims to explore the efficacy of restoring cellular NAD+ concentration through supplementation with the NAD+ precursor, nicotinamide mononucleotide (NMN), in the treatment of allergic asthma and to investigate the role of SIRT3 in mediating the effects of NAD+ precursors. In this research, NMN alleviated airway inflammation and reduced mucus secretion in house dust mite (HDM)-induced asthmatic mice. It also mitigated airway epithelial barrier disruption in HDM-induced asthma in vitro and in vivo. But inhibition of SIRT3 expression abolished the effects of NMN. Mechanistically, HDM induced SIRT3 SUMOylation and proteasomal degradation. Mutation of these two SIRT3 SUMO modification sites enhanced the stability of SIRT3. Additionally, SIRT3 was targeted by SENP1 which acted to de-conjugate SUMO. And down-regulation of SENP1 expression in HDM-induced models was reversed by NMN. Collectively, these findings suggest that NMN attenuates airway epithelial barrier dysfunction via inhibiting SIRT3 SUMOylation in asthma. Blockage of SIRT3 SUMOylation emerges as for the treatment of allergic asthma.

Bone-targeting engineered small extracellular vesicles carrying anti-miR-6359-CGGGAGC prevent valproic acid-induced bone loss

The clinical role and underlying mechanisms of valproic acid (VPA) on bone homeostasis remain controversial. Herein, we confirmed that VPA treatment was associated with decreased bone mass and bone mineral density (BMD) in both patients and mice. This effect was attributed to VPA-induced elevation in osteoclast formation and activity. Through RNA-sequencing, we observed a significant rise in precursor miR-6359 expression in VPA-treated osteoclast precursors in vitro, and further, a marked upregulation of mature miR-6359 (miR-6359) in vivo was demonstrated using quantitative real-time PCR (qRT-PCR) and miR-6359 fluorescent in situ hybridization (miR-6359-FISH). Specifically, the miR-6359 was predominantly increased in osteoclast precursors and macrophages but not in neutrophils, T lymphocytes, monocytes and bone marrow-derived mesenchymal stem cells (BMSCs) following VPA stimulation, which influenced osteoclast differentiation and bone-resorptive activity. Additionally, VPA-induced miR-6359 enrichment in osteoclast precursors enhanced reactive oxygen species (ROS) production by silencing the SIRT3 protein expression, followed by activation of the MAPK signaling pathway, which enhanced osteoclast formation and activity, thereby accelerating bone loss. Currently, there are no medications that can effectively treat VPA-induced bone loss. Therefore, we constructed engineered small extracellular vesicles (E-sEVs) targeting osteoclast precursors in bone and naturally carrying anti-miR-6359 by introducing of EXOmotif (CGGGAGC) in the 3'-end of the anti-miR-6359 sequence. We confirmed that the E-sEVs exhibited decent bone/osteoclast precursor targeting and exerted protective therapeutic effects on VPA-induced bone loss, but not on ovariectomy (OVX) and glucocorticoid-induced osteoporotic models, deepening our understanding of the underlying mechanism and treatment strategies for VPA-induced bone loss.

A review on SIRT3 and its natural small molecule activators as a potential Preventive and therapeutic target

Sirtuins (SIRTs) were originally characterized by yeast Sir2 as a lifespan regulator that is conserved in all three structural domains of bacteria, archaea and eukaryotes and belong to histone deacetylases consisting of seven members (SIRT1-SIRT7). Surprisingly, SIRTs have been shown to play important regulatory roles in almost all cellular functions, including mitochondrial biogenesis, oxidative stress, inflammation, cell growth, energy metabolism, neural function, and stress resistance. Among the SIRT members, sirtuin 3 (SIRT3) is one of the most important deacetylases that regulates the mitochondrial acetylation and plays a role in pathological processes, such as metabolism, DNA repair, oxidative stress, apoptosis and ferroptosis. Therefore, SIRT3 is considered as a potential target for the treatment of a variety of pathological diseases, including metabolic diseases, neurodegenerative diseases, age-related diseases and others. Furthermore, the isolation, screening, and development of SIRT3 signaling agonists, especially from natural products, have become a widely investigated objective. This paper describes the structure of SIRT3 protein, discusses the pathological process of SIRT3-mediated acetylation modification, and reviews the role of SIRT3 in diseases, SIRT3 activators and its related disease studies.

Sirtuins mediate mitochondrial quality control mechanisms: a novel therapeutic target for osteoporosis

Mitochondria plays a role in cell differentiation and apoptosis processes. Maintaining mitochondrial function is critical, and this involves various aspects of mitochondrial quality control such as protein homeostasis, biogenesis, dynamics, and mitophagy. Osteoporosis, a metabolic bone disorder, primarily arises from two factors: the dysregulation between lipogenic and osteogenic differentiation of aging bone marrow mesenchymal stem cells, and the imbalance between osteoblast-mediated bone formation and osteoclast-mediated bone resorption. Mitochondrial quality control has the potential to mitigate or even reverse the effects. Among the Sirtuin family, consisting of seven Sirtuins (SIRT1-7), SIRT1-SIRT6 play a crucial role in maintaining mitochondrial quality control. Additionally, SIRT1, SIRT3, SIRT6, and SIRT7 are directly involved in normal bone development and homeostasis by modulating bone cells. However, the precise mechanism by which these Sirtuins exert their effects remains unclear. This article reviews the impact of various aspects of mitochondrial quality control on osteoporosis, focusing on how SIRT1, SIRT3, and SIRT6 can improve osteoporosis by regulating mitochondrial protein homeostasis, biogenesis, and mitophagy. Furthermore, we provide an overview of the current state of clinical and preclinical drugs that can activate Sirtuins to improve osteoporosis. Specific Sirtuin-activating compounds are effective, but further studies are needed. The findings of this study may offer valuable insights for future research on osteoporosis and the development of clinical prevention and therapeutic target strategies.

KLF2/PPARγ axis contributes to trauma-induced heterotopic ossification by regulating mitochondrial dysfunction

Trauma-induced heterotopic ossification (HO) is a complex disorder after musculoskeletal injury and characterized by aberrant extraskeletal bone formation. Recent studies shed light on critical role of dysregulated osteogenic differentiation in aberrant bone formation. Krupel-like factor 2 (KLF2) and peroxisome proliferator-activated receptor gamma (PPARγ) are master adapter proteins that link cellular responses to osteogenesis; however, their roles and relationships in HO remain elusive. Using a murine burn/tenotomy model in vivo, we identified elevated KLF2 and reduced PPARγ levels in tendon stem/progenitor cells (TSPCs) during trauma-induced HO formation. Both KLF2 inhibition and PPARγ promotion reduced mature HO, whereas the effects of PPARγ promotion were abolished by KLF2 overexpression. Additionally, mitochondrial dysfunction and reactive oxygen species (ROS) production also increased after burn/tenotomy, and improvements in mitochondrial function (ROS scavenger) could alleviate HO formation, but were abolished by KLF2 activation and PPARγ suppression by affecting redox balance. Furthermore, in vitro, we found increased KLF2 and decreased PPARγ levels in osteogenically induced TSPCs. Both KLF2 inhibition and PPARγ promotion relieved osteogenesis by improving mitochondrial function and maintaining redox balance, and effects of PPARγ promotion were abolished by KLF2 overexpression. Our findings suggest that KLF2/PPARγ axis exerts regulatory effects on trauma-induced HO through modulation of mitochondrial dysfunction and ROS production in TSPCs by affecting redox balance. Targeting KLF2/PPARγ axis and mitochondrial dysfunction can represent attractive approaches to therapeutic intervention in trauma-induced HO.

Journey of Mineral Precursors in Bone Mineralization: Evolution and Inspiration for Biomimetic Design

Bone mineralization is a ubiquitous process among vertebrates that involves a dynamic physical/chemical interplay between the organic and inorganic components of bone tissues. It is now well documented that carbonated apatite, an inorganic component of bone, is proceeded through transient amorphous mineral precursors that transforms into the crystalline mineral phase. Here, the evolution on mineral precursors from their sources to the terminus in the bone mineralization process is reviewed. How organisms tightly control each step of mineralization to drive the formation, stabilization, and phase transformation of amorphous mineral precursors in the right place, at the right time, and rate are highlighted. The paradigm shifts in biomineralization and biomaterial design strategies are intertwined, which promotes breakthroughs in biomineralization-inspired material. The design principles and implementation methods of mineral precursor-based biomaterials in bone graft materials such as implant coatings, bone cements, hydrogels, and nanoparticles are detailed in the present manuscript. The biologically controlled mineralization mechanisms will hold promise for overcoming the barriers to the application of biomineralization-inspired biomaterials.

Melatonin rescues the mitochondrial function of bone marrow-derived mesenchymal stem cells and improves the repair of osteoporotic bone defect in ovariectomized rats

Osteoporotic bone defects, a severe complication of osteoporosis, are distinguished by a delayed bone healing process and poor repair quality. While bone marrow-derived mesenchymal stem cells (BMMSCs) are the primary origin of bone-forming osteoblasts, their mitochondrial function is impaired, leading to inadequate bone regeneration in osteoporotic patients. Melatonin is well-known for its antioxidant properties and regulation on bone metabolism. The present study postulated that melatonin has the potential to enhance the repair of osteoporotic bone defects by restoring the mitochondrial function of BMMSCs. In vitro administration of melatonin at varying concentrations (0.01, 1, and 100 μM) demonstrated a significant dose-dependent improvement in the mitochondrial function of BMMSCs obtained from ovariectomized rats (OVX-BMMSCs), as indicated by an elevation in mitochondrial membrane potential, adenosine triphosphate synthesis and expression of mitochondrial respiratory chain factors. Melatonin reduced the level of mitochondrial superoxide by activating the silent information regulator type 1 (SIRT1) and its downstream antioxidant enzymes, particularly superoxide dismutase 2 (SOD2). The protective effects of melatonin were found to be nullified upon silencing of Sirt1 or Sod2, underscoring the crucial role of the SIRT1-SOD2 axis in the melatonin-induced enhancement of mitochondrial energy metabolism in OVX-BMMSCs. To achieve a sustained and localized release of melatonin, silk fibroin scaffolds loaded with melatonin (SF@MT) were fabricated. The study involved the surgical creation of bilateral femur defects in OVX rats, followed by the implantation of SF@MT scaffolds. The results indicated that the application of melatonin partially restored the mitochondrial energy metabolism and osteogenic differentiation of OVX-BMMSCs by reinstating mitochondrial redox homeostasis. These findings suggest that the localized administration of melatonin through bone implants holds potential as a therapeutic approach for addressing osteoporotic bone defects.

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.

Retuning Mitochondrial Apoptosis/Mitophagy Balance via SIRT3-Energized and Microenvironment-Modulated Hydrogel Microspheres to Impede Osteoarthritis

Full-range therapeutic regimens for osteoarthritis (OA) should consider organs (joints)-tissues (cartilage)-cells (chondrocytes)-organelles cascade, of which the subcellular mitochondria dominate eukaryotic cells' fate, and thus causally influence OA progression. However, the dynamic regulation of mitochondrial rise and demise in impaired chondrocytes and the exact role of mitochondrial metronome sirtuins 3 (SIRT3) is not clarified. Herein, chondrocytes are treated with SIRT3 natural agonist dihydromyricetin (DMY) or chemical antagonist 3-TYP, respectively, to demonstrate the positive action of SIRT3 on preserving cartilage extracellular matrix (ECM). Molecular mechanical investigations disclose that SIRT3-induced chondroprotection depended on the repression of mitochondrial apoptosis (mtApoptosis) and the activation of mitophagy. Inspired by the high-level matrix proteinases and reactive oxygen species (ROS) in the OA environment, by anchoring gelatin methacrylate (GelMA) and benzenediboronic acid (PBA) to hyaluronic acid methacrylate (HAMA) with microfluidic technology, a dual-responsive hydrogel microsphere laden with DMY is tactfully fabricated and named as DMY@HAMA-GelMA-PBA (DMY@HGP). In vivo injection of DMY@HGP ameliorated cartilage abrasion and subchondral bone sclerosis, as well as promoted motor function recovery in post-traumatic OA (PTOA) model via recouping endogenous mtApoptosis and mitophagy balance. Overall, this study unveils a novel mitochondrial dynamic-oriented strategy, holding great promise for the precision treatment of OA.

The role of sirtuins in the regulatin of oxidative stress during the progress and therapy of type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disorder characterized by insulin resistance and impaired glucose homeostasis. Oxidative stress, arising from an imbalance between reactive oxygen species (ROS) production and antioxidant defense systems, plays a significant role in the development and progression of T2DM. The sirtuin family, particularly Sirt1, Sirt3, and Sirt6, have emerged as key regulators of oxidative stress in various cellular processes. This review aims to explore the role of the sirtuin family in oxidative stress during the progression of T2DM and their potential as therapeutic targets. We discussed the mechanisms through which sirtuins modulate oxidative stress, their impact on insulin sensitivity, and beta-cell function involved in T2DM. Furthermore, we highlight drugs targeting sirtuin activation and related complications in T2DM. This review summarizes the role as well as mechanism of sirtuins in the regulation of oxidative stress in T2DM and available drugs targeting sirtuins in clinic, which may provide novel insights into the mechanism and therapy of T2DM.

The miR-224-5p/SIRT3/AMPK/mTOR axis is involved in the melatonin-mediated inhibition of glucocorticoid-induced osteoporosis by activating autophagy

Melatonin has been shown to exert an inhibitory effect on osteoporosis. This study investigates the function of the miR-224-5p/SIRT3/AMPK/mTOR axis in melatonin-mediated effects against osteoporosis. Human bone marrow mesenchymal stem cells (hBMSCs) were treated with glucocorticoid dexamethasone to induce an in vitro osteoporosis model. After melatonin treatment, miR-224-5p and SIRT3 levels were measured by RT‒PCR. Transmission electron microscopy and immunofluorescence were conducted for evaluating autophagy. Western blotting was carried out to determine the expression of osteogenesis-related proteins (Runx2, OSX, OPN, and OCN), SIRT3-AMPK-mTOR axis, and autophagy-related markers (LC3 and p62). Alizarin red staining was used to measure matrix mineralization. The data showed that melatonin inhibited dexamethasone-induced osteoporosis in vitro, and enhanced autophagic levels (as indicated by increased LC3 puncta, LC3II/I ratio, and autophagic vacuoles). In terms of the mechanisms, melatonin decreased miR-224-5p expression and increased SIRT3. SRIT3 was shown to be a direct target of miR-224-5p. miR-224-5p upregulation or SIRT3 downregulation reversed the effects of melatonin on osteoporosis and suppressed autophagy. Additionally, miR-224-5p inhibited SIRT3 expression and AMPK pathway activation. In summary, we discovered that melatonin suppressed glucocorticoid-induced osteoporosis and autophagy inhibition via the miR-224-5p/SIRT3/AMPK/mTOR axis.

Zinc defends against Parthanatos and promotes functional recovery after spinal cord injury through SIRT3-mediated anti-oxidative stress and mitophagy

INTRODUCTION

Spinal cord injury (SCI) is a central nervous system injury that is primarily traumatic and manifests as motor, sensory, and autonomic dysfunction below the level of damage. Our previous studies confirmed the ability of zinc to protect mitochondria, protect neurons and promote spinal cord recovery. However, the role of zinc in Parthanatos is unknown.

AIM

We investigated the effects of zinc in Parthanatos from oxidative stress and mitophagy. We elucidated the role of SIRT3 in providing new ideas for treating spinal cord injury.

THE RESULTS

Zinc protected SCI mice by regulating Parthanatos. On the one hand, zinc eliminated ROS directly through SIRT3 deacetylation targeting SOD2 to alleviate Parthanatos. On the other hand, zinc eliminated ROS indirectly through SIRT3-mediated promotion of mitophagy to alleviate Parthanatos.

CONCLUSION

Zinc defends against Parthanatos and promotes functional recovery after spinal cord injury through SIRT3-mediated anti-oxidative stress and mitophagy.

Targeting Mitochondrial Sirtuins in Age-Related Neurodegenerative Diseases and Fibrosis

Aging is a natural and complex biological process that is associated with widespread functional declines in numerous physiological processes, terminally affecting multiple organs and tissues. Fibrosis and neurodegenerative diseases (NDs) often occur with aging, imposing large burdens on public health worldwide, and there are currently no effective treatment strategies for these diseases. Mitochondrial sirtuins (SIRT3-5), which are members of the sirtuin family of NAD+-dependent deacylases and ADP-ribosyltransferases, are capable of regulating mitochondrial function by modifying mitochondrial proteins that participate in the regulation of cell survival under various physiological and pathological conditions. A growing body of evidence has revealed that SIRT3-5 exert protective effects against fibrosis in multiple organs and tissues, including the heart, liver, and kidney. SIRT3-5 are also involved in multiple age-related NDs, including Alzheimer's disease, Parkinson's disease, and Huntington's disease. Furthermore, SIRT3-5 have been noted as promising targets for antifibrotic therapies and the treatment of NDs. This review systematically highlights recent advances in knowledge regarding the role of SIRT3-5 in fibrosis and NDs and discusses SIRT3-5 as therapeutic targets for NDs and fibrosis.

Oxidative stress as a key modulator of cell fate decision in osteoarthritis and osteoporosis: a narrative review

During aging and after traumatic injuries, cartilage and bone cells are exposed to various pathophysiologic mediators, including reactive oxygen species (ROS), damage-associated molecular patterns, and proinflammatory cytokines. This detrimental environment triggers cellular stress and subsequent dysfunction, which not only contributes to the development of associated diseases, that is, osteoporosis and osteoarthritis, but also impairs regenerative processes. To counter ROS-mediated stress and reduce the overall tissue damage, cells possess diverse defense mechanisms. However, cellular antioxidative capacities are limited and thus ROS accumulation can lead to aberrant cell fate decisions, which have adverse effects on cartilage and bone homeostasis. In this narrative review, we address oxidative stress as a major driver of pathophysiologic processes in cartilage and bone, including senescence, misdirected differentiation, cell death, mitochondrial dysfunction, and impaired mitophagy by illustrating the consequences on tissue homeostasis and regeneration. Moreover, we elaborate cellular defense mechanisms, with a particular focus on oxidative stress response and mitophagy, and briefly discuss respective therapeutic strategies to improve cell and tissue protection.

Heat-Killed Lactobacillus rhamnosus ATCC 7469 Improved UVB-Induced Photoaging Via Antiwrinkle and Antimelanogenesis Impacts

Exposure of ultraviolet B (UVB) radiation is the main factor from the environment to cause skin photoaging. Lactobacillus rhamnosus ATCC 7469, is a probiotic strain with a good track record for enhancing human health. The present study conducted the impacts of heat-killed L. rhamnosus ATCC 7469 (RL) on photoaging in vitro using mouse skin fibroblast (MSF) cells and human epidermal melanocytes (HEM) exposed to UVB. The results showed that (1) RL-protected UVB-induced cytotoxicity relating to absorb UVB and reduce DNA damage. (2) RL exerted the antiwrinkle impact involved in two aspects. Firstly, RL downregulated MMP-1, 2, 3 expressions associating with MAPK signaling, resulting in the increased the protein expression of COL1A1, further booting type I collagen abundant thereby promoting the antiwrinkle impact in MSF cells. Secondly, RL reduced ROS content, further decreasing oxidative damage relating to Nrf2/Sirt3/SOD2 signaling, thereby promoting the antiwrinkle impact in MSF cells. (3) RL suppressed tyrosinase and TYRP-2 activity and/or levels associating with PKA/CREB/MITF signaling, thereby promoting antimelanogenesis impact in HEM cells. In conclusion, our findings suggest that RL could reduce photoaging caused by UVB via antiwrinkle and antimelanogenesis properties and may be a potential antiphotoaging beneficial component, which is applied in the cosmetic industry.