PINK1/Parkin-Mediated Mitophagy Plays a Protective Role in the Bone Impairment Caused by Aluminum Exposure

mtROS-mediated mitophagy is involved in aflatoxin-B1 induced liver injury in ducks

Aflatoxin B1 (AFB1) is highly toxic to the liver and can cause excessive production of mitochondrial reactive oxygen species (mtROS) in hepatocytes, leading to oxidative stress, inflammation, fibrosis, cirrhosis, and even liver cancer. The overproduction of mtROS can induce mitophagy, but whether mtROS and mitophagy are involved in the liver injury induced by AFB1 in ducks remains unclear. In this study, we first demonstrated that overproduction of mtROS and mitophagy occurred during liver injury induced by AFB1 exposure in ducks. Then, by inhibiting mtROS and mitophagy, we found that the damage caused by AFB1 in ducks was significantly alleviated, and the overproduction of mtROS induced by AFB1 exposure could mediate the occurrence of mitophagy. These results suggested that mtROS-mediated mitophagy is involved in AFB1-induced duck liver injury, and they may be the prevention and treatment targets of AFB1 hepatotoxicity.

Bone protective effects of the polysaccharides from Grifola frondosa on ovariectomy-induced osteoporosis in mice via inhibiting PINK1/Parkin signaling, oxidative stress and inflammation

BACKGROUND

Polysaccharides from Grifola frondosa(GFP) have gained worldwide attention owing to their promising biological activities and potential health benefits.

PURPOSE

This study aimed to investigate the effects of GFP on alleviation of osteoporosis in ovariectomized (OVX) mice and examine the underlying mechanism.

METHOD

A mouse model of postmenopausal osteoporosis was established by OVX method, Forty eight C57BL/6 female mice were randomly divided into Normal group, OVX alone (Model group, n = 8), OVX + 10 mg/kg GFP (GFP-L group, n = 8), OVX + 20 mg/kg GFP (GFP-M group, n = 8), OVX + 40 mg/kg GFP (GFP-H group, n = 8), OVX + 10 mg/kg Estradiol valerate (Positive group, n = 8).

RESULTS

The results showed that compared with Model group, the concentrations of interleukin (IL)-1β, interleukin (IL)-6 and Tumor necrosis factor-α (TNF-α) were significantly reduced, the activity of superoxide dismutase (SOD) and glutathione (GSH) were significantly increased, the content of myeloperoxidase (MPO) and malondialdehyde (MDA) were significantly reduced, and the proteins levels of PINK1, Parkin, Beclin-1 and LC3-II were significantly decreased in the GFP groups.

CONCLUSION

This study demonstrates that GFP alleviates ovariectomy-induced osteoporosis via reduced secretion of inflammatory cytokines, improvement in the oxidative stress status in the body, and inhibition of the PINK1/Parkin signaling pathway.

Calcium supplementation attenuates fluoride-induced bone injury via PINK1/Parkin-mediated mitophagy and mitochondrial apoptosis in mice

Excessive consumption of fluoride can cause skeletal fluorosis. Mitophagy has been identified as a novel target for bone disorders. Meanwhile, calcium supplementation has shown great potential for mitigating fluoride-related bone damage. Hence, this study aimed to elucidate the association between mitophagy and skeletal fluorosis and the precise mechanisms through which calcium alleviates these injuries. A 100 mg/L sodium fluoride (NaF) exposure model in Parkin knockout (Parkin-/-) mice and a 100 mg/L NaF exposure mouse model with 1% calcium carbonate (CaCO3) intervention were established in the current study. Fluoride exposure caused the impairment of mitochondria and activation of PTEN-induced putative kinase1 (PINK1)/E3 ubiquitin ligase Park2 (Parkin)-mediated mitophagy and mitochondrial apoptosis in the bones, which were restored after blocking Parkin. Additionally, the intervention model showed fluoride-exposed mice exhibited abnormal bone trabecula and mechanical properties. Still, these bone injuries could be effectively attenuated by adding 1% calcium to their diet, which reversed fluoride-activated mitophagy and apoptosis. To summarize, fluoride can activate bone mitophagy through the PINK1/Parkin pathway and mitochondrial apoptosis. Parkin-/- and 1% calcium provide protection against fluoride-induced bone damage. Notably, this study provides theoretical bases for the prevention and therapy of animal and human health and safety caused by environmental fluoride contamination.

Acer truncatum Bunge seed oil ameliorated oxaliplatin-induced demyelination by improving mitochondrial dysfunction via the Pink1/Parkin mitophagy pathway

Dietary nutritional support for special populations is an effective and feasible method to improve the quality of life of patients and reduce medical pressure. Acer truncatum Bunge seed oil (ATSO) is widely recognized for its ability to promote nerve myelin regeneration. To evaluate the ameliorative effects of ATSO on chemotherapy-induced demyelination, a zebrafish model of chemotherapy-induced demyelination was established. The results showed that 100 μg mL-1 of ATSO reversed tail morphology damage, axon degeneration, touch response delay, ROS level upregulation and the expression of myelin basic protein decrease in chemotherapy-induced zebrafish. In addition, the expression of myelin markers (including sox10, krox20, and pmp22) in oxaliplatin-induced cells was markedly reversed by ATSO and its active components (gondoic acid, erucic acid, and nervonic acid). ATSO and its active components could reverse demyelination by ameliorating mitochondrial dysfunction. Conversely, linoleic acid and linolenic acid promoted demyelination by exacerbating mitochondrial dysfunction. Moreover, the Pink1/Parkin pathway was recognized as the main reason for ATSO and its active components improving mitochondrial function by activating mitophagy and restoring autophagic flow. Taken together, this study demonstrated that ATSO and its active components could be further developed as novel functional food ingredients to antagonize demyelination.

Aluminum-maltol induced oxidative stress and reduced AMPK activity via BCK-related energy supply failure in C6 cell

Aluminum (Al) exposure significantly interferes with the energy supply in astrocytes, which may be a potential mechanism of Al-induced neurotoxicity. This study was designed to explore the mechanisms of Al-induced energy supply impairment in rat C6 astroglioma cell line. Aluminum-maltolate (Al(mal)3) (0.1 mM, 24 h) exposure significantly decreased brain-type creatine kinase (BCK) co-localization with the endoplasmic reticulum (ER) and resulted in mitochondrial dysfunctions, accompanied by a decrease in AMPK phosphorylation. The results of molecular docking showed that Al(mal)3 increased BCK's hydrophobicity and hindered the localization movement of BCK between subcells·H2O2 co-administration was found to exacerbate mitochondrial dysfunction, Ca2+ dyshomeostasis, and apoptosis. After treated with Al(mal)3, additional oxidative stress contributed to BCK activity inhibition but did not promote a further decrease in AMPK phosphorylation. The activation of p-AMPK by its agonist can partially restore mitochondrial function, BCK activity, and ER-localized-BCK levels in Al(mal)3-treated astrocytes. In summary, Al exposure resulted in a sustained depletion of the mitochondrial and antioxidant systems, which was associated with reduced p-AMPK activity and decreased ER-localized-BCK levels in astrocytes. This study provides a theoretical basis for exploring the mechanisms of neurotoxicity induced by Al exposure.

Parkin-mediated mitophagy protects against aluminum trichloride-induced hippocampal apoptosis in mice via the mtROS-NLRP3 pathway

Aluminum is a neurotoxic food contaminant. Aluminum trichloride (AlCl3) causes hippocampal mitochondrial damage, leading to hippocampal injury. Damaged mitochondria can release mitochondrial reactive oxygen species (mtROS) and activate nucleotide-binding oligomerization domain-like receptor-containing 3 (NLRP3) inflammasomes and apoptosis. E3 ubiquitin ligase PARK2 (Parkin)-mediated mitophagy can attenuate mitochondrial damage. However, the role of mitophagy in AlCl3-induced mice hippocampal damage and its regulatory mechanism remain elusive. First, C57BL/6 N mice were treated with 0, 44.825, 89.65, and 179.3 mg/kg body weight AlCl3 drinking water for 90 d. Apoptosis, NLRP3-inflammasome activation and mitochondrial damage were increased in AlCl3-induced hippocampal damage. In addition, Parkin-mediated mitophagy peaked in the middle-dose group and was slightly attenuated in the high-dose group. Subsequently, we used wild-type and Parkin knockout (Parkin-/-) mice to investigate the AlCl3-induced hippocampal damage. The results showed that Parkin-/- inhibited mitophagy, and aggravated AlCl3-induced mitochondrial damage, NLRP3-inflammasome activation, apoptosis and hippocampal damage. Finally, we administered MitoQ (mtROS inhibitor) and MCC950 (NLRP3 inhibitor) to AlCl3-treated Parkin-/- mice to investigate the mechanism of Parkin-mediated mitophagy. The results showed that inhibition of mtROS and NLRP3 attenuated hippocampal NLRP3-inflammasome activation, apoptosis, and damage in AlCl3-treated Parkin-/- mice. These findings indicate that Parkin-mediated mitophagy protects against AlCl3-induced hippocampal apoptosis in mice via the mtROS-NLRP3 pathway.

Necroptosis and NLPR3 inflammasome activation mediated by ROS/JNK pathway participate in AlCl3-induced kidney damage

Aluminum (Al) is a common environmental pollutant that can induce kidney damage. However, the mechanism is not clear. In the present study, to explored the exact mechanism of AlCl₃-induced nephrotoxicity, C57BL/6 N male mice and HK-2 cells were used as experimental subjects. Our results showed that Al induced reactive oxygen species (ROS) overproduction, c-Jun N-terminal kinase (JNK) signaling activation, RIPK3-dependent necroptosis, NLRP3 inflammasome activation, and kidney damage. In addition, inhibiting JNK signaling could downregulate the protein expressions of necroptosis and NLRP3 inflammasome, thereby alleviating kidney damage. Meanwhile, clearing ROS effectively inhibited JNK signaling activation, which in turn inhibited necroptosis and NLRP3 inflammasome activation, ultimately alleviating kidney damage. In conclusion, these findings suggest that necroptosis and NLPR3 inflammasome activation mediated by ROS/JNK pathway participate in AlCl₃-induced kidney damage.

Mitophagy alleviates AIF-mediated spleen apoptosis induced by AlCl3 through Parkin stabilization in mice

Aluminium (Al) accumulates in the spleen and causes spleen apoptosis. Mitochondrial dyshomeostasis represents primary mechanisms of spleen apoptosis induced by Al. Apoptosis-inducing factor (AIF) is located in the gap of the mitochondrial membrane and can be released into the nucleus, leading to apoptosis. Phosphatase and tensin homolog (PTEN)-induced putative kinase1 (PINK1)/E3 ubiquitin ligase PARK2 (Parkin)-mediated mitophagy maintains mitochondrial homeostasis by removing damaged mitochondria, but its function in AIF-mediated spleen apoptosis induced by Al is not clear. In our study, aluminium trichloride (AlCl₃) was diluted in water for 90 d and administered to 75 male C57BL/6N mice at 0, 44.8, 59.8, 89.7, and 179.3 mg/kg body weight. AlCl₃ triggered PINK1/Parkin pathway-mediated mitophagy, induced AIF release and AIF-mediated spleen apoptosis. AlCl₃ was administered to sixty male C57BL/6N mice of wild type and Parkin knockout for 90 d at 0 and 179.3 mg/kg body weight. The results indicated that Parkin deficiency decreased mitophagy, aggravated mitochondrial damage, AIF release and AIF-mediated spleen apoptosis induced by AlCl₃. According to our results, PINK1/Parkin-mediated mitophagy and AIF-mediated spleen apoptosis are caused by AlCl₃, whereas mitophagy is protective in AIF-mediated apoptosis induced by AlCl₃.

Curcumin Alleviates Aflatoxin B1-Induced Liver Pyroptosis and Fibrosis by Regulating the JAK2/NLRP3 Signaling Pathway in Ducks

Aflatoxin B₁ (AFB₁) is a serious pollutant in feed and food which causes liver inflammation, fibrosis, and even cirrhosis. The Janus kinase 2 (JAK2)/signal transducers and activators of the transcription 3 (STAT3) signaling pathway is widely involved in inflammatory response and promotes the activation of nod-like receptor protein 3 (NLRP3) inflammasome, thus leading to pyroptosis and fibrosis. Curcumin is a natural compound with anti-inflammatory and anti-cancer properties. However, whether AFB₁ exposure leads to the activation of the JAK2/NLRP3 signaling pathway in the liver and whether curcumin can regulate this pathway to influence pyroptosis and fibrosis in the liver remains unclear. In order to clarify these problems, we first treated ducklings with 0, 30, or 60 µg/kg AFB₁ for 21 days. We found that AFB₁ exposure caused growth inhibition, liver structural and functional damage, and activated JAK2/NLRP3-mediated liver pyroptosis and fibrosis in ducks. Secondly, ducklings were divided into a control group, 60 µg/kg AFB₁ group, and 60 µg/kg AFB₁ + 500 mg/kg curcumin group. We found that curcumin significantly inhibited the activation of the JAK2/STAT3 pathway and NLRP3 inflammasome, as well as the occurrence of pyroptosis and fibrosis in AFB₁-exposed duck livers. These results suggested that curcumin alleviated AFB₁-induced liver pyroptosis and fibrosis by regulating the JAK2/NLRP3 signaling pathway in ducks. Curcumin is a potential agent for preventing and treating liver toxicity of AFB₁.

Selenium Improves Bone Microenvironment-Related Hematopoiesis and Immunity in T-2 Toxin-Exposed Mice

The T-2 toxin is one of the most frequent contaminants in the environment and agricultural production globally. It exerts a wide range of toxic effects. Selenium (Se), as an antioxidant, has the potential to be widely used to antagonize mycotoxin toxicity. To investigate the protective effects of Se on bone microenvironment (BM)-related hematopoiesis and immunity after T-2 toxin exposure, 36 male mice were treated with the T-2 toxin (1 mg/kg) and/or Se (0.2 mg/kg) by intragastric administration for 28 days. The results showed that Se alleviated T-2 toxin-induced cytopenia and splenic extramedullary hematopoiesis. Se also significantly relieved T-2 toxin-induced immunosuppression, as assessed by immune factors and lymphocytes. Furthermore, Se also attenuated oxidative stress and apoptosis and improved the BM in T-2 toxin-exposed mice. Therefore, Se improves BM-related hematopoiesis and immunity after T-2 toxin exposure. This study provides references for identifying the toxic mechanism and screening potential therapeutic drugs of the T-2 toxin.

T-2 toxin inhibits osteoblastic differentiation and mineralization involving mutual regulation between Wnt signaling pathway and autophagy

Mycotoxins are most frequent contaminants in environment and agricultural production globally. The T-2 toxin of Fusarium species is the most toxic type of A trichothecene mycotoxins. T-2 toxin can accumulate in bone and cause bone development disorders. Osteoblast is the functional cell responsible for bone formation. Whereas, the mechanism of T-2 toxin toxicity on osteoblast remains unknown. In present study, MC3T3-E1 cells were treated with 0, 2, 4, and 8 nM T-2 toxin for 24h to explore the effect of T-2 toxin on the differentiation and mineralization of osteoblasts. Subsequently, autophagy and Wnt intervention agents were used to explore the roles of autophagy and Wnt signaling pathway in T-2 toxin-induced osteoblastic differentiation and mineralization disorders, respectively. The results showed that 2 nM of T-2 toxin had no significant effect on cell vitality, but 4 and 8 nM of T-2 significantly inhibited cell viability. All doses of T-2 toxin inhibited both osteoblastic differentiation and mineralization, as assessed by alkaline phosphatase staining, Alizarin red S staining, and protein expressions of osteogenic proteins. In addition, the activation of Wnt signaling pathway mitigated T-2 toxin-induced osteoblast impairment, while the inhibition of autophagy exacerbated it. Our results also indicated that there was a positive feedback loop between the Wnt signaling pathway and autophagy.

Rapamycin regulates osteogenic differentiation through Parkin-mediated mitophagy in rheumatoid arthritis

Varying degrees of bone destruction and bone loss occur in the development of rheumatoid arthritis (RA). Nevertheless, the mechanism underlying osteoporosis in the development of RA is not completely elucidated. Recent evidence indicates that mitophagy may play a vital role in regulating the differentiation and function of preosteoblast. Parkin is associated with mitophagy and various inflammatory diseases, but the precise role of Parkin in the treatment of osteoporosis in RA is unclear. In the present study, we found that the abnormal bone metabolism of RA is related to the activation of the mechanistic targets of mTORC1 pathway, and chronic inflammation which regulates the differentiation of preosteoblast through mitophagy. In this study, we found that Parkin was upregulated, and the mitochondrion was damaged in tumor necrosis factor alpha (TNF-α) stimulated preosteoblasts. Rapamycin (RAPA, an mTORC1 pathway blocker) upregulation of Parkin-mediated mitophagy tends to attenuate mitochondrial impairment caused by TNF-α in preosteoblasts. Theexperimentinvivo demonstrated that the combination therapy with TNF-α neutralizing antibody and RAPA significantly reduced osteoporosis in AIA mice. Drug inhibition of this pathway can be a potential treatment for osteoporosis in patients with RA.

Effects of a Resistance Training Protocol on Physical Performance, Body Composition, Bone Metabolism, and Systemic Homeostasis in Patients Diagnosed with Parkinson's Disease: A Pilot Study

Parkinson's disease (PD) is a neurodegenerative disorder characterized by motor impairments and it is correlated with loss of bone mineral density. This study aimed to analyze the effects of resistance training on bone metabolism, systemic homeostasis, body composition, and physical performance in people with PD. Thirteen subjects (age 64.83 ± 5.70) with PD diagnosis were recruited. Participants performed neuromuscular tests, body composition assessment, and blood sample analysis at baseline, and after an 11 weeks-training period. Each training session lasted 90 min, three times a week. The participants had significant improvements in the timed up and go (p < 0.01), sit to stand (p < 0.01), dominant peg-board (p < 0.05), dominant foot-reaction time (p < 0.01), and functional reach tests (p < 0.05). They showed better pressure foot distributions in the left forefoot (p < 0.05) and hindfoot (p < 0.05) and increased cervical right lateral bending angle (p < 0.05). The protocol affects bone metabolism markers osteocalcin (p < 0.05), calcium (p < 0.01), PTH (p < 0.01), the C-terminal telopeptide (CTX) (p < 0.01), and vitamin D (p < 0.05). Eleven weeks of resistance training improved manual dexterity, static and dynamic balance, reaction time, cervical ROM, and reduced bone loss in people with PD.

Dibutyl phthalate causes MC3T3-E1 cell damage by increasing ROS to promote the PINK1/Parkin-mediated mitophagy

Dibutyl phthalate (DBP) is a plasticizer widely used in daily production, which causes serious environmental pollution, and damage to brain, liver, kidney, and lung by producing excessive reactive oxygen species (ROS) after entering the body. DBP can also cause skeletal dysplasia, but it is unclear whether ROS is involved. In addition, overproduction of ROS can activate mitophagy, which is an important mechanism for regulating mitochondrial quality and cell homeostasis. In order to investigate whether DBP can damage MC3T3-E1 cells (osteoblast cell line) and whether ROS and mitophagy are involved, DBP toxicity experiment, Parkin gene silencing experiment, and N-acetylcysteine (NAC) intervention experiment were performed on MC3T3-E1 cells in turn. First, we found that DBP caused MC3T3-E1 cell viability decline and osteogenic dysfunction, accompanied by the overproduction of ROS and the activation of mitophagy. Then, we found that silencing Parkin expression alleviated DBP-induced apoptosis and osteogenic dysfunction of MC3T3-E1 cells. In addition, NAC treatment inhibited the PINK1/Parkin-mediated mitophagy and alleviated the apoptosis and osteogenic dysfunction of MC3T3-E1 cells caused by DBP. Our research results showed that DBP could cause MC3T3-E1 cell damage by increasing ROS to promote the PINK1/Parkin-mediated mitophagy.

T-2 toxin-induced femur lesion is accompanied by autophagy and apoptosis associated with Wnt/β-catenin signaling in mice

T-2 toxin is one of the most common mycotoxins found in grain foods, animal feed, and other agricultural by-products causing food contamination and health threat. The skeletal system is the main target tissue for T-2 toxin. T-2 toxin exposure is also recognized as a potential contributor to multiple types of bone diseases, including Kashin-Beck disease. However, the mechanisms of T-2 toxin-induced bone toxicity remain unclear. In this study, 60 male C57BL/6 mice were exposed T-2 toxin with 0, 0.5, 1 or 2 mg/kg body weight by intragastric administration for 28 days, respectively. Femora were collected for the detections of femur lesion, bone formation factors, oxidative stress, autophagy, apoptosis, and Wnt/β-catenin signaling. Our research showed that T-2 toxin caused bone formation disorders, presenting as the reduction of the BMD and femur length, bone structure changes and abnormal bone formation proteins expressions, along with enhanced oxidative stress. Meanwhile, T-2 toxin increased expressions of autophagy-related proteins (Beclin 1, ATG5, p62, and LC3), and promoted apoptosis in mouse femur. Moreover, T-2 toxin suppressed the Wnt/β-catenin signaling and expressions of downstream target genes. Taken together, our data indicated T-2 toxin-induced femur lesion was accompanied by autophagy and apoptosis, which was associated with Wnt/β-catenin signaling.

PINK1/Parkin-mediated mitophagy is activated to protect against AFB1-induced kidney damage in mice

Aflatoxin B₁ (AFB₁) is a toxic food pollutant that has extensive deleterious impacts on the kidney. Oxidative stress represents the primary mechanism of AFB₁ nephrotoxicity and can also cause mitochondrial damage. Damaged mitochondria can trigger apoptosis leading to kidney injury. PINK1/Parkin-mediated mitophagy can alleviate mitochondrial injury to maintain cellular homeostasis, however, its role in AFB₁-induced kidney damage is unknown. To investigate the effect of PINK1/Parkin-mediated mitophagy on kidney impairment triggered by AFB₁, 40 male wild-type (WT) C57BL/6N mice were first assigned to 4 groups and orally exposed to AFB₁ at 0, 0.5, 0.75, and 1 mg/kg body weight (BW) for 28 days. The results revealed that AFB₁ induced kidney damage, oxidative stress, mitochondrial damage, apoptosis and activated PINK1/Parkin-mediated mitophagy with a dose-dependent effect. Then, 20 male WT C57BL/6N mice and 20 male Parkin knockout (Parkin^-/-) C57BL/6N mice were assigned to 4 groups and orally exposed to AFB₁ at 0, 1, 0, and 1 mg/kg BW for 28 days. The results revealed that Parkin^-/- suppressed mitophagy and exacerbated kidney damage, oxidative stress, mitochondrial damage, and apoptosis under AFB₁ exposure. The aforementioned evidences demonstrate that PINK1/Parkin-mediated mitophagy is activated by AFB₁ and protects against kidney damage in mice.

Activation of PINK1/Parkin-mediated mitophagy protects against apoptosis in kidney damage caused by aluminum

Aluminum (Al) induces apoptosis via oxidative stress and/or mitochondrial damage. Kidney is the main organ of Al excretion, but whether Al causes apoptosis in kidney of mice remains unclear. Mitophagy maintains cell homeostasis via clearing damaged mitochondria and reducing oxidative stress, but the role in kidney damage caused by Al has also not been investigated. In this study, firstly, forty wild type (WT) male C57 mice were randomly exposed to AlCl₃ at 0, 44.825, 89.65 or 179.3 mg/kg body weight in drinking water for 90 days, respectively. Our results confirmed that Al induced apoptosis, and activated PINK1 (phosphatase and tensin homolog (PTEN)-induced putative kinase1)/Parkin (E3 ubiquitin ligase PARK2)-mediated mitophagy with the dose increased. And secondly, to further assess the role of PINK1/Parkin-mediated mitophagy in Al-induced kidney damage, twenty Parkin knockout (Parkin^-/-) mice and twenty WT mice were divided into WT group, WT + Al group, Parkin^-/- group, and Parkin^-/- + Al group, and they were provided with AlCl₃ at a dose of 0 or 179.3 mg/kg body weight in drinking water for 90 days, respectively. The results showed that Parkin^-/- induced more severe kidney injury caused by Al. Besides, Parkin^-/- aggravated oxidative stress and apoptosis caused by Al. Overall, our findings indicate that the activation of PINK1/Parkin-mediated mitophagy protects against apoptosis in kidney damage caused by Al.

Parkinson's in the bone

Patients with Parkinson’s disease (PD) exhibit systemic deficits, including arthritis and osteoporosis-like symptoms. However, the questions, how the deficits in periphery organs or tissues occur in PD patients, and what are the relationship (s) of the periphery tissue deficits with the brain pathology (e.g., dopamine neuron loss), are at the beginning stage to be investigated. Notice that both PD and osteoporosis are the products of a complex interaction of genetic and environmental risk factors. Genetic mutations in numerous genes have been identified in patients either with recessive or autosomal dominant PD. Most of these PD risk genes are ubiquitously expressed; and many of them are involved in regulation of bone metabolism. Here, we review the functions of the PD risk genes in regulating bone remodeling and homeostasis. The knowledge gaps in our understanding of the bone-to-brain axis in PD development are also outlined.

ROS-mediated mitophagy and apoptosis are involved in aluminum-induced femoral impairment in mice

The problem of excessive aluminum (Al) content in food is widespread. After Al enters the body, it can cause mineral metabolism imbalance and reactive oxygen species (ROS) overproduction, which ultimately leads to bone impairment. ROS is mainly produced in mitochondria and acts on mitochondria. Mitochondrial damage is closely related to mitophagy and apoptosis. In order to clarify whether ROS-mediated mitophagy and apoptosis are involved in Al-induced femoral impairment, forty-eight male C57BL/6 N mice were exposed to AlCl₃ (179.3 mg/kg) and/or NAC (100 mg/kg) for 90 days. Our results showed that NAC inhibited the mitophagy and apoptosis, and alleviated growth inhibition, mineral metabolism imbalance, structural damage, decreased bone mineral density and decreased bone formation factor expressions in the femora of Al-treated mice. These results suggest that ROS-mediated mitophagy and apoptosis are involved in Al-induced femoral impairment in mice, exogenous ROS clearance is a potential strategy for the treatment of Al-induced bone impairment.

Parkin-mediated mitochondrial quality control protects against aluminum-induced liver damage in mice

Aluminum (Al) is known to be hepatotoxic. Oxidative stress is the main mechanism of liver injury caused by Al, and can also lead to mitochondrial damage. Mitochondrial damage is a prerequisite for mitochondrial quality control (MQC) dysregulation. Parkin can activate MQC and maintain mitochondrial homeostasis. However, the role of Parkin-mediated MQC in Al-induced liver damage has not been elucidated. In this study, forty male wild type (WT) C57BL/6N mice were treated with 0, 44.825, 89.65 or 179.3 mg/kg body weight AlCl₃ in drinking water for 90 days, respectively. We found that Al induced mitophagy and disrupted mitochondrial dynamics and mitochondrial biogenesis. Then, twenty male WT C57BL/6N mice and twenty male Parkin knockout (Parkin^-/-) C57BL/6N mice were divided into four groups and treated with 0, 89.65, 0, 89.65 mg/kg body weight AlCl₃ in drinking water for 90 days, respectively. We found that Parkin^-/- inhibited mitophagy and further disrupted mitochondrial dynamics and mitochondrial biogenesis. These results indicated that Parkin-mediated MQC could be disrupted by Al and protected against Al-induced liver damage.