BNIP3L/NIX-mediated mitophagy protects against glucocorticoid-induced synapse defects

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

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

HUWE1-mediated ubiquitination and degradation of oxidative damage repair gene ATM maintains mitochondrial quality control system in lens epithelial cells

Mitochondrial dysfunction, resulting from a diminished oxidative damage repair capacity of mitochondrial DNA (mtDNA) in peripheral lens epithelial cells (LECs), is a key pathogenic mechanism in age-related cortical cataract (ARCC). This study aims to investigate the potential role of the E3 ligase HUWE1 and its ubiquitination substrate, the oxidative damage repair gene ATM, in the pathogenesis of ARCC. Our findings reveal that ATM protein expression is downregulated in human peripheral lens epithelial cells and the turbid cortex, correlating with increased expression of HUWE1. Overexpression of ATM is shown to repair damaged mtDNA, protect mitochondria in LECs from oxidative damage, inhibit mitochondrial fission, enhance mitochondrial biogenesis and mitophagy, and prevent LECs apoptosis. Conversely, overexpression of HUWE1 may negate the protective effects of ATM via the ubiquitination pathway, promote oxidative stress-induced mitochondrial damage, increase the expression of mitochondrial fission proteins Drp1/Fis1, lead to mitochondrial network fragmentation and LECs apoptosis. In a SD rat lens model ex vitro, the ATM inhibitor AZD0156 exacerbated lens opacity, whereas the mitochondrial fission inhibitor Mdivi-1 restored lens transparency. These results suggest that modulating key molecules involved in oxidative damage repair and mitochondrial fission pathways could enhance mitochondrial quality control, paving the way for the development of targeted molecular therapies for the prevention and treatment of ARCC.

Paeonol regulates autophagy through the PI3K-AKT-mTOR signaling pathway to inhibit apoptosis of osteocytes

Osteoporosis is the most common complication of glucocorticoids and predisposes to fractures. Excessive apoptosis of osteocytes is the pathological feature of glucocorticoid-induced osteoporosis. Paeonol, an effective component of Traditional Chinese Medicine Cortex Moutan, known for its anti-inflammatory and analgesic properties, has a long clinical application history. However, the regulatory effect of paeonol on the fate of osteocytes under excessive glucocorticoid remains unclear. The present study aimed to investigate the effect of paeonol against osteocyte death and osteoporosis induced by glucocorticoid and to explore the underlying mechanisms. We found that paeonol not only improved the low proliferation rate of osteocytes induced by dexamethasone but also weakened the dexamethasone-induced apoptosis of osteocytes by stimulating cytoprotective autophagy. Subsequently, proteomic sequencing identified the phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K) - protein kinase B (AKT) signaling pathway as the potential target of paeonol in attenuating dexamethasone-induced osteocyte injury, and the PI3K activator and inhibitor confirmed this hypothesis. In vivo, paeonol alleviated glucocorticoid-induced osteoporosis, promoted autophagy and inhibited apoptosis of osteocytes by regulating PI3K phosphorylation. In brief, paeonol protects osteocytes from dexamethasone-derived apoptosis by increasing protective autophagy, further inhibiting osteoporosis. Its autophagy-promoting effect was associated with inhibition of PI3K-AKT-mechanistic target of rapamycin (mTOR) of osteocytes.

TBK1 alleviates triptolide-induced nephrotoxic injury by up-regulating mitophagy in HK2 cells

Tripterygium wilfordii has been used for a long time to treat autoimmune diseases. Its toxic side effects limit its clinical application. Mitophagy plays a protective role in various diseases. TANK-binding kinase 1 (TBK1) is a mitophagy-promoting molecule. This study aimed to investigate whether TBK1 could alleviate triptolide (TP)-induced nephrotoxicity by regulating mitophagy. To establish TP-induced nephrotoxic injury in animal model, 16 Sprague-Dawley rats were administered with TP by gavage, then renal tissues were collected for hematoxylin and eosin (HE) staining, western blotting and immunofluorescence analysis. To investigate whether up-regulation of TBK1 could alleviate TP-induced nephrotoxic injury and the specific mechanism, HK-2 cells were cultured in vitro, transfected with TBK1-overexpression recombinant lentivirus, then treated with TP. Western blotting, immunofluorescence, flow cytometry, multifunctional microplate detector were used to detect the relevant molecules. Here we found that TP caused kidney function damage, declined mitophagy levels, decreased the expression of TBK1 and mitophagy-related proteins in rats. TP stimulation decreased cell viability, mitochondrial membrane potential, mitophagy-protein, the formation of mito-autophagosomes and mito-autophagolysosomes in HK-2 cells. Upregulating TBK1 could reverse these damages. In summary, TP-induced cell injury had decreased mitophagy levels. Up-regulating TBK1 could increase mitophagy and further alleviate TP-induced cell injury.

Iron Metabolism and Muscle Aging: Where Ferritinophagy Meets Mitochondrial Quality Control

In older adults with reduced physical performance, an increase in the labile iron pool within skeletal muscle is observed. This accumulation is associated with an altered expression of mitochondrial quality control (MQC) markers and increased mitochondrial DNA damage, supporting the hypothesis that impaired MQC contributes to muscle dysfunction during aging. The autophagy-lysosome system plays a critical role in MQC by tagging and engulfing proteins and organelles for degradation in lysosomes. The endolysosomal system is also instrumental in transferrin recycling, which, in turn, regulates cellular iron uptake. In the neuromuscular system, the autophagy-lysosome system supports the structural integrity of neuromuscular junctions, and its dysfunction contributes to muscle atrophy. While MQC was thought to protect against iron-induced cell death, the discovery of ferroptosis, a form of iron-dependent cell death, has highlighted a complex interplay between MQC and iron-inflicted damage. Ferritinophagy, the autophagic degradation of ferritin, if overactivated, can induce ferroptosis. Alternatively, aging may impair ferritinophagy, leading to ferritin accumulation and the release of toxic labile iron under stress, exacerbating oxidative damage and cellular senescence. Physical activity supports muscle health also by preserving mitochondrial quantity and quality and enhancing bioenergetics. However, therapeutic strategies for preventing or reversing physical function decline in aging are still lacking due to the insufficient understanding of the underlying mechanisms. Unveiling how disruptions in iron homeostasis impact muscle quality in older adults may allow for the development of therapeutic strategies targeting iron handling to alleviate age-associated muscle decline.

The effect of mitochondrial-associated endoplasmic reticulum membranes (MAMs) modulation: New insights into therapeutic targets for depression

Depression is a prevalent mental disorder with high morbidity and mortality and its pathogenesis remains exactly unclarified. However, mitochondria and endoplasmic reticulum (ER) are two highly dynamic organelles that perform an indispensable role in the development of depression. Mitochondrial dysfunction and ER stress are recognized as vital pathological hallmarks in depression. The changes of intracellular activities such as mitochondrial dynamics, mitophagy, energy metabolism and ER stress are closely correlated with the progression of depression. Moreover, organelles interactions are conducive to homeostasis and cellular functions, and mitochondrial-associated endoplasmic reticulum membranes (MAMs) serve as signaling hubs of the two organelles and the coupling of the pathological progression. The main roles of MAMs are involved in metabolism, signal transduction, lipid transport, and maintenance of its structure and function. At present, accumulating studies elucidated that MAMs have gradually become a novel therapeutic target in treatment of depression. In the review, we focus on influence of mitochondria dysfunction and ER stress on depression. Furthermore, we discuss the underlying role of MAMs in depression and highlight natural products targeting MAMs as potential antidepressants to treat depression.

Mechanism of arsenic regulation of mitochondrial damage and autophagy induced synaptic damage through SIRT1 and protective effect of melatonin in HT22 cell

Arsenic (As), a widespread environmental pollutant, can induce severe neurological damage worldwide; however, the underlying mechanisms remain unclear. Sirtuin 1 (SIRT1) has been reported to exert neuroprotective effects against various neurological diseases by resisting mitochondrial damage and autophagy through deacetylation. In this study, we established a model of HT22 cells exposed to NaAsO2 and examined the levels of mitochondrial, autophagy, and synaptic damage in HT22 cells and HT22 cells with high expression of SIRT1 (pre-treated with the agonist SRT1720) 24 h after exposure. Our results suggest that NaAsO2 exposure induces down-regulation of SIRT1, causing mitochondrial damage and activation of autophagy, which in turn leads to synaptic damage. Notably, melatonin (Mel) intervention upregulated SIRT1 and attenuated mitochondrial damage and autophagy, restoring synaptic damage. In conclusion, the results of the present study indicate that As causes neurotoxicity by decreasing SIRT1 production, causing mitochondrial damage and activating autophagy, which provides fundamental data for further study of arsenic neurotoxicity. In addition, blocking this pathway attenuated the synaptic damage of arsenic exposure, which provides a new therapeutic avenue for arsenic neurotoxicity.

From energy metabolism to mood regulation: The rise of lactate as a therapeutic target

BACKGROUND

Disruption of cerebral energy metabolism is increasingly recognized as a key factor in the pathophysiology of mood disorders. Lactate, beyond its role as a metabolic byproduct, is now understood to be a critical player in brain energy homeostasis and a modulator of neuronal function. Recent advances in understanding lactate shuttling between astrocytes and neurons have opened new avenues for exploring its multifaceted roles in mood regulation. Exercise, known to modulate brain lactate levels, further underscores the potential of lactate as a therapeutic target in mood disorders.

AIM OF REVIEW

This review delves into the alterations in cerebral lactate associated with mood disorders, emphasizing their implications for brain energy dynamics and signaling pathways. Additionally, we discuss the therapeutic potential of lactate in mood disorders, particularly through its capacity to remodel cerebral function. We conclude by assessing the promise of exercise-induced lactate production as a novel strategy for mood disorder treatment.

KEY SCIENTIFIC CONCEPTS OF THE REVIEW

Alterations in brain lactate may contribute to the pathogenesis of mood disorders. In several studies, lactate is not only a substrate for brain energy metabolism, but also a molecule that triggers signaling cascades. Specifically, lactate is involved in the regulation of neurogenesis, neuroplasticity, endothelial cell function, and microglia lysosomal acidification, therefore improving mood disorders. Meanwhile, exercise as a low-risk intervention strategy can improve mood disorders through lactate regulation. Thus, the evidence from this review supports that lactate could be a potential therapeutic target for mood disorder, contributing to a deeper understanding of mood disorder pathogenesis and intervention.

Shen-fu Injection Modulates HIF- 1α/BNIP3-Mediated Mitophagy to Alleviate Myocardial Ischemia-Reperfusion Injury

Coronary reperfusion therapy is the most common surgical treatment for myocardial infarction, but it can further induce myocardial ischemia-reperfusion injury (MIRI). Therefore, MIRI following coronary intervention is a challenging clinical issue. This study aims to investigate the involvement of HIF- 1α/BNIP3-mediated mitophagy in the protective effects of Shen-fu Injection (SFI) on MIRI in rats. Key targets and signaling pathways of myocardial MIRI were analyzed using high-throughput transcriptome data from the GSE240842 dataset in the GEO database.To establish the MIRI rat model, the left anterior descending coronary artery was ligated for 30 min, followed by reperfusion for 120 min. Hypoxia/reoxygenation (H/R) in neonatal rat primary cardiomyocytes was induced by oxygen-glucose deprivation for 4 h, followed by reoxygenation for 2 h. Two hours after reperfusion, assessments included myocardial infarction area, CK-MB, CTnI, HE staining, TUNEL, mitochondrial ultrastructure and autophagosomes, HIF- 1α, BNIP3, LC3B-II, LC3B-I protein expression, immunofluorescence, and qRT-PCR. Cardiac function was also evaluated using M-mode ultrasound 2 h after reperfusion. In cardiomyocytes, CCK- 8, EdU cell proliferation levels, scratch assay, mitochondrial membrane potential, ROS levels, cardiomyocyte apoptosis, protein expression levels, and immunofluorescence were assessed 2 h after reoxygenation. Our results indicate that HIF- 1α and BNIP3 are key targets in MIRI. SFI upregulates HIF- 1α expression, promoting moderate mitophagy. This process clears excessively damaged mitochondria, reduces cardiomyocyte apoptosis, and decreases myocardial injury. Additionally, SFI reduces autophagosome accumulation, lowers ROS production, and stabilizes membrane potential. Consequently, the area of myocardial infarction is reduced, and cardiac function is improved. SFI activates the HIF- 1α/BNIP3 pathway to mediate moderate mitophagy, effectively reducing cardiomyocyte apoptosis and alleviating myocardial ischemia-reperfusion injury, thereby protecting cardiomyocytes.

Aging and autophagic phenotypic changes in bone marrow mesenchymal stem cells in glucocorticoid-induced osteonecrosis

BACKGROUND

Glucocorticoid (GC) overuse is the main cause of osteonecrosis of the femoral head (ONFH). The dysfunction of bone marrow mesenchymal stem cells (BMSCs) plays an important role in ONFH pathogenesis. Physiological concentrations of GCs can induce the osteogenic differentiation of BMSCs; however, intervention with high concentrations of GC may lead to changes in aging and autophagy in certain cell types.

METHODS

We generated an ONFH mouse model by injecting C57BL/6 J mice with MPS. BMSCs were harvested from the femora and tibiae of mice and were analyzed for osteogenesis, adipogenesis, senescence, and cell proliferation. In vitro, BMSCs were treated with different concentrations of GC for 48 h, followed by functional analyses to identify differentially expressed genes (DEGs) associated with ONFH. Additionally, various bioinformatics analyses were performed to identify differentially expressed genes in ONFH.

RESULTS

BMSCs from ONFH mice showed signs of aging, as indicated by increased SA-β-gal positive cells (4.4-fold) and upregulated p53 (2.6-fold) and p21 (2.0-fold) protein expression. It is also accompanied by changes in osteogenic/lipogenic differentiation ability. Bioinformatics analysis further verified these findings. High-dose GC stimulation significantly induced cellular senescence of BMSCs, as indicated by an increase in SA-β-gal positive cells (6.2-fold) and a decrease in autophagy levels. GC stimulation changes the differentiation fate of BMSCs.

CONCLUSIONS

Our results indicated that GC-induced ONFH was associated with changes in aging and autophagy in BMSCs. GC not only directly affected the osteogenic differentiation of BMSCs but also indirectly affected their differentiation fate through aging and autophagy changes.

Restoration of Miro1's N-terminal GTPase function alleviates prenatal stress-induced mitochondrial fission via Drp1 modulation

BACKGROUND

Prenatal stress exposure irreversibly impairs mitochondrial dynamics, including mitochondrial trafficking and morphology in offspring, leading to neurodevelopmental and neuropsychiatric disorders in adulthood. Thus, understanding the molecular mechanism controlling mitochondrial dynamics in differentiating neurons is crucial to prevent the prenatal stress-induced impairments in behavior. We investigated the interplay between mitochondrial transport and fusion/fission in differentiating neurons exposed to prenatal stress, leading to ensuing behavior impairments, and then tried to identify the primary regulator that modulates both phenomena.

METHODS

We used primary hippocampal neurons of mice exposed to prenatal stress and human induced-pluripotent stem cell (hiPSC)-derived neurons, for investigating the impact of glucocorticoid on mitochondrial dynamics during differentiation. For constructing mouse models, we used AAV vectors into mouse pups exposed to prenatal stress to regulate protein expressions in hippocampal regions.

RESULTS

We first observed that prenatal exposure to glucocorticoids induced motility arrest and fragmentation of mitochondria in differentiating neurons derived from mouse fetuses (E18) and human induced pluripotent stem cells (hiPSCs). Further, glucocorticoid exposure during neurogenesis selectively downregulated Miro1 and increased Drp1 phosphorylation (Ser616). MIRO1 overexpression restored mitochondrial motility and increased intramitochondrial calcium influx through ER-mitochondria contact (ERMC) formation. Furthermore, we determined that the N-terminal GTPase domain of Miro1 plays a critical role in ERMC formation, which then decreased Drp1 phosphorylation (Ser616). Similarly, prenatal corticosterone exposure led to impaired neuropsychiatric and cognitive function in the offspring by affecting mitochondrial distribution and synaptogenesis, rescued by Miro1WT, but not N-terminal GTPase active form Miro1P26V, expression.

CONCLUSION

Prenatal glucocorticoid-mediated Miro1 downregulation contributes to dysfunction in mitochondrial dynamics through Drp1 phosphorylation (Ser616) in differentiating neurons.

A vascular endothelial cell, neuron, and microglia tri-culture model to study hypertension-related depression

Hypertension-related Depression (HD) is a complex mental disorder that exerts a significant negative impact on patients' quality of life. Previous studies have demonstrated that damages to vascular endothelial and hippocampus are the primary pathological features in HD rats. Under hypertensive conditions, inflammatory cytokines in peripheral blood vessels can induce central nervous system inflammation through penetration of a damaged blood-brain barrier, peripheral immune cells, and neural pathways, damaging the brain and triggering HD. Therefore, interactions between vascular endothelial cells, neurons, and glial cells are critical for the understanding of HD. However, in vivo animal models are often limited by the complexity of intrinsic systems, high inter-individual variability, and stringent ethical regulations. A reliable model that could be easily manipulated is needed for investigating the mechanisms involved in communication between vascular endothelial cells, neurons, and glial cells in HD. We therefore aimed to create a composite tri-culture model consisting of rat aortic endothelial cells (RAECs), neurons, and microglia to study HD. First, RAECs were stimulated with lipopolysaccharide to mimic endothelial injury under hypertensive conditions. Vascular endothelial function and inflammatory levels were assessed using fluorescent probes and enzyme-linked immunosorbent assays. RAECs treated with 1 μg/ml LPS for 24 h had reduced levels of nitric oxide, increased levels of endothelin-1 and inflammatory mediators. These findings are consistent with the endothelial dysfunction and inflammatory responses observed in spontaneously hypertensive rats, which suggests that the lipopolysaccharide-induced RAECs model effectively mimics key pathological features of hypertension-related endothelial injury. Subsequently, the supernatants from lipopolysaccharide-induced RAECs were combined with 200 μM corticosterone and transferred to neuron-microglia co-cultures to simulate damages to hippocampal neuron under HD conditions. To evaluate the features of cells, neuronal viability was measured by CCK-8 and live-dead assays. Nissl staining was used to assess neuronal Nissl bodies, while the levels of inflammatory factors and monoamine neurotransmitters in the culture supernatants were evaluated by enzyme-linked immunosorbent assays. Reactive oxygen species in neurons were visualized by a fluorescent probe, apoptosis was detected using TUNEL assays, and immunofluorescence was used to assess microglial phenotypes and the levels of TLR4 and NF-κB. It was found that neurons in the tri-culture model had reduced viability, higher levels of apoptosis, fewer Nissl bodies, increased inflammation, and reduced levels of monoamine neurotransmitters. Additionally, the number of M1 microglia was increased, along with elevated levels of TLR4 and NF-κB proteins. These findings were similar to damages of hippocampal neuron, abnormal levels of monoamine neurotransmitters, microglia polarization, and hippocampal inflammatory response observed in the HD rat model. In conclusion, our findings indicate that the tri-culture model can effectively simulate the pathological characteristics of HD, especially in vascular endothelial damage, neuroinflammation, monoamine neurotransmitters disorders. Therefore, the tri-culture model would provides a reliable and invaluable experimental tool for further research on the pathogenesis and treatment of HD.

Targeted activation of ErbB4 receptor ameliorates neuronal deficits and neuroinflammation in a food-borne polystyrene microplastic exposed mouse model

The impact of polystyrene microplastics (PS-MPs) on the nervous system has been documented in the literature. Numerous studies have demonstrated that the activation of the epidermal growth factor receptor 4 (ErbB4) is crucial in neuronal injury and regeneration processes. This study investigated the role of targeted activation of ErbB4 receptor through a small molecule agonist, 4-bromo-1-hydroxy-2-naphthoic acid (C11H7BrO3, E4A), in mitigating PS-MPs-induced neuronal injury. The findings revealed that targeted activation of ErbB4 receptor significantly ameliorated cognitive behavioral deficits in mice exposed to PS-MPs. Furthermore, E4A treatment upregulated the expression of dedicator of cytokinesis 3 (DOCK3) and Sirtuin 3 (SIRT3) and mitigated mitochondrial and synaptic dysfunction within the hippocampus of PS-MPs-exposed mice. E4A also diminished the activation of the TLR4-NF-κB-NLRP3 signaling pathway, consequently reducing neuroinflammation. In vitro experiments demonstrated that E4A partially alleviated PS-MPs-induced hippocampal neuronal injury and its effects on microglial inflammation. In conclusion, the findings of this study indicate that targeted activation of ErbB4 receptor may mitigate neuronal damage and subsequent neuroinflammation, thereby alleviating hippocampal neuronal injury induced by PS-MPs exposure and ameliorating cognitive dysfunction. These results offer valuable insights for the development of potential therapeutic strategies.

Activating autophagy to eliminate toxic protein aggregates with small molecules in neurodegenerative diseases

Neurodegenerative diseases (NDs), such as Alzheimer disease, Parkinson disease, Huntington disease, amyotrophic lateral sclerosis, and frontotemporal dementia, are well known to pose formidable challenges for their treatment due to their intricate pathogenesis and substantial variability among patients, including differences in environmental exposures and genetic predispositions. One of the defining characteristics of NDs is widely reported to be the buildup of misfolded proteins. For example, Alzheimer disease is marked by amyloid beta and hyperphosphorylated Tau aggregates, whereas Parkinson disease exhibits α-synuclein aggregates. Amyotrophic lateral sclerosis and frontotemporal dementia exhibit TAR DNA-binding protein 43, superoxide dismutase 1, and fused-in sarcoma protein aggregates, and Huntington disease involves mutant huntingtin and polyglutamine aggregates. These misfolded proteins are the key biomarkers of NDs and also serve as potential therapeutic targets, as they can be addressed through autophagy, a process that removes excess cellular inclusions to maintain homeostasis. Various forms of autophagy, including macroautophagy, chaperone-mediated autophagy, and microautophagy, hold a promise in eliminating toxic proteins implicated in NDs. In this review, we focus on elucidating the regulatory connections between autophagy and toxic proteins in NDs, summarizing the cause of the aggregates, exploring their impact on autophagy mechanisms, and discussing how autophagy can regulate toxic protein aggregation. Moreover, we underscore the activation of autophagy as a potential therapeutic strategy across different NDs and small molecules capable of activating autophagy pathways, such as rapamycin targeting the mTOR pathway to clear α-synuclein and Sertraline targeting the AMPK/mTOR/RPS6KB1 pathway to clear Tau, to further illustrate their potential in NDs' therapeutic intervention. Together, these findings would provide new insights into current research trends and propose small-molecule drugs targeting autophagy as promising potential strategies for the future ND therapies. SIGNIFICANCE STATEMENT: This review provides an in-depth overview of the potential of activating autophagy to eliminate toxic protein aggregates in the treatment of neurodegenerative diseases. It also elucidates the fascinating interrelationships between toxic proteins and the process of autophagy of "chasing and escaping" phenomenon. Moreover, the review further discusses the progress utilizing small molecules to activate autophagy to improve the efficacy of therapies for neurodegenerative diseases by removing toxic protein aggregates.

Copper aggravated synaptic damage after traumatic brain injury by downregulating BNIP3-mediated mitophagy

Synaptic damage is a crucial pathological process in traumatic brain injury. However, the mechanisms driving this process remain poorly understood. In this report, we demonstrate that the accumulation of damaged mitochondria, resulting from impaired mitphagy, plays a significant role in causing synaptic damage. Moreover, copper induced downregulation of BNIP3 is a key player in regulating mitophagy. DMSA alleviates synaptic damage and mitochondrial dysfunction by promoting urinary excretion of copper. Mechanistically, we find that copper downregulate BNIP3 by increasing the nuclear translocation of NFKB, which is triggered by TRIM25-mediated ubiquitination-dependent degradation of NFKBIA. Our study underscores the importance of copper accumulation in the regulation of BNIP3-mediated mitophagy and suggests that therapeutic targeting of the copper-TRIM25-NFKB-BNIP3 axis holds promise to attenuate synaptic damage after traumatic brain injury.

Effect of Supplementation of Quercetagetin on the Antioxidant Function, Liver Mitochondrial Function and Gut Microbiota of Broilers at High Stocking Density

This study investigates the effects of quercetagetin (QG) supplementation on the antioxidant capacity, liver mitochondrial function, and cecal microbiota of broilers raised under high-density conditions. A 2 × 2 factorial design with 144 one-day-old WOD168 broilers, which were allocated to two stocking densities (LD: 4 birds per cage, equivalent to 11.1 birds per square meter; HD: eight birds per cage, equivalent to 22.2 birds per square meter) and two levels of dietary supplementation of QG (0 and 20 mg/kg). At the conclusion of day 21, broilers of similar body weights were randomly allocated into four groups (22 to 42 d): control (CON), QG treatment (QG), high stocking density (HSD), and high stocking density with QG supplementation (H_QG). The results demonstrated that HD groups significantly reduced broiler growth performance, including body weight (BW), average daily gain (ADG), and average daily feed intake (ADFI) (p < 0.05). Additionally, HD groups increased serum stress hormone levels (CORT and ACTH), pro-inflammatory cytokines (IL-1β and IL-6) (p < 0.05), while decreasing liver antioxidant enzyme activities (GSH-Px, T-SOD), serum CAT and T-SOD activities, and mitochondrial function (GSH, complex I-III, ATP contents) (p < 0.05). However, dietary supplementation with 20 mg/kg QG significantly alleviated the negative effects induced by HSD, restoring growth performance, stress hormone levels, immune parameters, and liver antioxidant and mitochondrial function. Moreover, QG supplementation markedly improved cecal microbiota composition, enhancing gut health. Correlation analysis revealed a strong association between microbial composition and overall broiler health, indicating that gut microbiota plays a critical role in mediating these beneficial effects. In conclusion, QG exhibits protective effects against oxidative stress, mitochondrial dysfunction, and gut microbiota imbalance induced by high-density rearing, suggesting its potential as a functional feed additive to improve broiler health under intensive farming conditions.

The role of HIF-1α/BNIP3/mitophagy in acrylonitrile-induced neuronal death in HT22 cells and mice: A potential neuroprotection target

Acrylonitrile (AN) is a widely utilized organic compound in the production of diverse industrial synthetic materials. While acute exposure to AN can cause neurotoxicity, the precise mechanism remains unclear. Hypoxia-inducible factor 1 alpha (HIF-1α) is a pivotal transcription factor that coordinates and orchestrates multiple physiological processes to adapt to hypoxic conditions, ensuring cellular survival and homeostasis. In this study, we used in vitro (cultured mouse hippocampal neuronal cell line, HT22) and in vivo (AN exposed mice) approaches to investigate the potential modulator effects of HIF-1α in AN-induced neurotoxicity. In vitro, AN exposure caused concentration-dependent toxicity in HT22 cells, which was paralleled by increased Bax levels while decreasing Bcl-2. Exposure to AN resulted in reduced protein levels of HIF-1α, Bcl-2 19-kDa interacting protein 3 (BNIP3), microtubule-associated protein 1 light chain 3 beta (LC3B) and Beclin1, while increased the protein levels of the translocase of outer mitochondrial membrane 20 (TOM20). Furthermore, mitochondrial morphology and function were compromised, suggesting that AN impaired HIF-1α/BNIP3-mediated mitochondrial autophagy and promoted apoptosis. Treatment with a HIF-1α activator, cobalt chloride (CoCl2), reversed these effects, while pretreatment with a HIF-1α inhibitor, 2-methoxyestradiol (2-MeOE2), augmented them. In BNIP3 overexpressing HT22 cells, enhanced cell viability and reduced apoptosis rates were observed. Furthermore, the HIF-1α/BNIP3 pathway was activated by the prolyl hydroxylase (PHD2) inhibitor, deferoxamine (DFO), which increased HT22 cell viability. Similarly, the activation of HIF-1α by administering 20 mg/kg of CoCl2 was found to alleviate neurotoxicity in mice. This treatment enhanced elevations of autophagy protein expression and co-localization of BNIP3 and LC3B. In summary, under normoxia, AN induced neurotoxicity by promoting PHD2-mediated HIF-1α degradation, disrupted the BNIP3-mediated mitophagy pathway, and enhanced apoptosis. Our findings underscore the effect of the HIF-1α/BNIP3-mediated mitochondrial autophagy in AN-induced neurotoxicity and suggest potential therapeutic strategies involving HIF-1α activation or BNIP3 overexpression for AN poisoning treatment.

Mitophagy in ischemic heart disease: molecular mechanisms and clinical management

The influence of the mitochondrial control system on ischemic heart disease has become a major focus of current research. Mitophagy, as a very crucial part of the mitochondrial control system, plays a special role in ischemic heart disease, unlike mitochondrial dynamics. The published reviews have not explored in detail the unique function of mitophagy in ischemic heart disease, therefore, the aim of this paper is to summarize how mitophagy regulates the progression of ischemic heart disease. We conclude that mitophagy affects ischemic heart disease by promoting cardiomyocyte hypertrophy and fibrosis, the progression of oxidative stress, the development of inflammation, and cardiomyocyte death, and that the specific mechanisms of mitophagy are worthy of further investigation.

Chronic unpredictable stress induces anxiety-like behavior and oxidative stress, leading to diminished ovarian reserve

Chronic stress can adversely affect the female reproductive endocrine system, potentially leading to disorders and impairments in ovarian function. However, current research lacks comprehensive understanding regarding the biochemical characteristics and underlying mechanisms of ovarian damage induced by chronic stress. We established a stable chronic unpredictable stress (CUS)-induced diminished ovarian reserve (DOR) animal model. Our findings demonstrated that prolonged CUS treatment over eight weeks resulted in increased atresia follicles in female mice. This atresia was accompanied by decreased AMH and increased FSH levels. Furthermore, we observed elevated levels of corticosterone both in the peripheral blood and within the ovary. Additionally, we detected abnormalities in ATP metabolism within the ovarian tissue. CUS exposure led to oxidative stress in the ovaries, fostering a microenvironment characterized by oxidative damage to mouse ovarian granulosa cells (mGCs) and heightened levels of reactive oxygen species. Furthermore, CUS prompted mGCs to undergo apoptosis via the mitochondrial pathway. These findings indicate a direct association between the fundamental physiological alterations leading to DOR and the oxidative phosphorylation processes within mGCs. The diminished ATP production by mGCs, triggered by CUS, emerges as a pivotal indicator of CUS-induced DOR. Our study establishes an animal model to investigate the impact of chronic stress on ovarian reserve function and sheds light on potential mechanisms underlying this phenomenon.

Baicalin attenuates corticosterone-induced hippocampal neuronal injury by activating mitophagy in an AMPK-dependent manner

Defective mitophagy is closely related to the neuronal dysfunction and major depressive disorder (MDD). Our previous study found that baicalin could enhance nip-like protein (NIX)-mediated mitophagy and exhibit antidepressant effects, and predicted that AMPK may be the pharmacological target of baicalin. However, validated experiments are lacking. In the present study, we first demonstrated the effect of baicalin on hippocampal NIX-mediated mitophagy in CORT-induced depressive mice. Secondly, we transfected siRNA to knockdown AMPK, PGC-1α, and NIX respectively in HT22 cells, and detected the effects of baicalin on mitochondrial function, AMPK/PGC-1α/NIX pathway protein expression and mitophagy levels. Finally, AAV-shAMPKα was injected into hippocampal CA3 to knockdown AMPK in mice to validate the antidepressant effects of baicalin in vivo. The results showed that CORT induced depressive-like behaviors, accompanied with neuronal damage, mitochondrial injury, and inhibited mitophagy in the hippocampus, which were prevented by baicalin (20 mg/kg) treatment. In HT22 cells, baicalin remarkably ameliorated mitochondrial dysfunction and mitophagy disturbance induced by CORT, and these protective effects of baicalin were blocked by knockdown of AMPK, PGC-1α and NIX. Moreover, the beneficial effects of baicalin on depressive-like behaviors and NIX-mediated mitophagy were suppressed by knockdown of AMPKα in mice. Our present results further demonstrated that baicalin promotes NIX-mediated mitophagy and improves depression in an AMPK-dependent manner.

Natural products that alleviate depression: The putative role of autophagy

Major depressive disorder (MDD) is a common mental disorder that severely disrupts psychosocial function and decreases the quality of life. Although the pathophysiological mechanism underlying MDD is complex and remains unclear, emerging evidence suggests that autophagy dysfunction plays a role in MDD occurrence and progression. Natural products serve as a major source of drug discovery and exert tremendous potential in developing antidepressants. Recently published reports are paying more attention on the autophagy regulatory effect of antidepressant natural products. In this review, we comprehensively discuss the abnormal changes occurred in multiple autophagy stages in MDD patients, and animal and cell models of depression. Importantly, we emphasize the regulatory mechanism of antidepressant natural products on disturbed autophagy, including monomeric compounds, bioactive components, crude extracts, and traditional Chinese medicine formulae. Our comprehensive review suggests that enhancing autophagy might be a novel approach for MDD treatment, and natural products restore autophagy homeostasis to facilitate the renovation of mitochondria, impede neuroinflammation, and enhance neuroplasticity, thereby alleviating depression.

Gnetupendin A protects against ischemic stroke through activating the PI3K/AKT/mTOR-dependent autophagy pathway

BACKGROUND

Autophagy has been recently emerged as a prominent factor in the pathogenesis of ischemic stroke (IS) and is increasingly being considered as a potential therapeutic target for IS. Gnetum parvifolium has been identified as a potential therapeutic agent for inflammatory diseases such as rheumatism and traumatic injuries. However, the pharmacological effects of Gnetupindin A (GA), a stilbene compound isolated from Gnetum parvifolium, have not been fully elucidated until now.

OBJECTIVE

Here we identified the therapeutic potential of GA for IS, deeply exploring the possible mechanisms related to its regulation of autophagy.

METHODS

The mouse model of middle cerebral artery occlusion-reperfusion (MCAO/R) and the oxygen-glucose deprivation reperfusion (OGD/R)-exposed cells served as models to study the protection of GA against IS. The adeno-associated virus (AAV) encoding shAtg5, in conjunction with autophagy inhibitor 3-Methyladenine (3-MA) were utilized to explore the role of GA in regulating autophagy following IS. Molecular docking, CETSA, and DARTS were used to identify the specific therapeutic target of GA. PI3K inhibitor LY294002 was employed to test the participation of PI3K in GA-mediated autophagy and neuroprotective effects following IS.

RESULTS

Our findings revealed that treatment with GA significantly alleviated the brain infract volume, edema, improved neurological deficits and attenuated apoptosis. Mechanistically, we found that GA promoted autophagic flow both in vivo and in vitro after IS. Notably, neural-targeted knockdown of Atg5 abolished the neuroprotective effects mediated by GA. Inhibition of autophagy using 3-MA blocked the attenuation on apoptosis induced by GA. Moreover, molecular docking, CETSA, and DARTS analysis demonstrated that GA specifically targeted PI3K and further inhibited the activation of PI3K/AKT/mTOR signaling pathway. LY294002, which inhibits PI3K, reversed GA-induced autophagy and neuroprotective effects on OGD/R-treated cells.

CONCLUSION

We demonstrated, for the first time, that GA protects against IS through promoting the PI3K/AKT/mTOR-dependent autophagy pathway. Our findings provide a novel mechanistic insight into the anti-IS effect of GA in regulating autophagy.

KPNB1-ATF4 induces BNIP3-dependent mitophagy to drive odontoblastic differentiation in dental pulp stem cells

BACKGROUND

Differentiating dental pulp stem cells (DPSCs) into odontoblasts is a critical process for tooth self-repair and dentine‒pulp engineering strategies in the clinic. However, the mechanism underlying the regulation of DPSC odontoblastic differentiation remains largely unknown. Here, we demonstrated that BCL-2 interacting protein 3 (BNIP3)-dependent mitophagy is associated with importin subunit beta-1 (KPNB1)-activating transcription factor 4 (ATF4), which promotes DPSC odontoblastic differentiation.

METHODS

The key genes involved in DPSC odontogenic differentiation were identified via bioinformatics. Stable silencing or overexpression of BNIP3 was performed to investigate its impact on DPSC differentiation in vitro (n ≥ 3). To explore the role of BNIP3 in vivo, tooth root fragments loaded with the hydrogel-transfected DPSC complex were implanted into nude mice (n ≥ 6). Dual-luciferase reporter assays and chromatin immunoprecipitation (ChIP) polymerase chain reaction (PCR) were conducted to explore the binding site of ATF4 to the BNIP3 promoter (n ≥ 3). Mitochondrial function experiments were performed to investigate the impact of ATF4-BNIP3 on mitochondria (n ≥ 3). Immunoprecipitation (IP) mass spectrometry (MS) was used to investigate the interaction between ATF4 and its binding protein, KPNB1. Plasmids containing wild-type (WT)/mutant (MUT)-nuclear localization signal (NLS) forms of ATF4 were constructed to determine the specific amino acid residues recognized by KPNB1 and their effects on DPSC odontoblastic differentiation (n ≥ 3).

RESULTS

Compared with those in the control group, the levels of autophagy and mitophagy, especially BNIP3-dependent mitophagy, were greater in the DPSC odontoblastic differentiation group (P < 0.05). Genetic silencing or overexpression of BNIP3 demonstrated that BNIP3 expression was positively correlated with the transition of DPSCs into odontoblasts both in vitro and in vivo (P < 0.05). ATF4 regulates the expression of BNIP3 by directly binding to approximately -1292 to -1279 bp and approximately -1185 to -1172 bp within the BNIP3 promoter region, which is associated with mitophagy and mitochondrial reactive oxygen species (mtROS) levels (P < 0.05). Moreover, ATF4 increased mitophagy, mitochondrial function, and cell differentiation potential via BNIP3 (P < 0.05). Mechanistically, KPNB1 is a novel interacting protein of ATF4 that specifically recognizes amino acids (aa) 280-299 within ATF4 to control its translocation into the nucleus and subsequent transcription and differentiation processes (P < 0.05).

CONCLUSIONS

We reported that the critical role of KPNB1/ATF4/BNIP3 axis-dependent mitophagy could provide new cues for the regeneration of the dental pulp‒dentin complex in DPSCs.

Targeting selective autophagy in CNS disorders by small-molecule compounds

Autophagy functions as the primary cellular mechanism for clearing unwanted intracellular contents. Emerging evidence suggests that the selective elimination of intracellular organelles through autophagy, compared to the increased bulk autophagic flux, is crucial for the pathological progression of central nervous system (CNS) disorders. Notably, autophagic removal of mitochondria, known as mitophagy, is well-understood in an unhealthy brain. Accumulated data indicate that selective autophagy of other substrates, including protein aggregates, liposomes, and endoplasmic reticulum, plays distinctive roles in various pathological stages. Despite variations in substrates, the molecular mechanisms governing selective autophagy can be broadly categorized into two types: ubiquitin-dependent and -independent pathways, both of which can be subjected to regulation by small-molecule compounds. Notably, natural products provide the remarkable possibility for future structural optimization to regulate the highly selective autophagic clearance of diverse substrates. In this context, we emphasize the selectivity of autophagy in regulating CNS disorders and provide an overview of chemical compounds capable of modulating selective autophagy in these disorders, along with the underlying mechanisms. Further exploration of the functions of these compounds will in turn advance our understanding of autophagic contributions to brain disorders and illuminate precise therapeutic strategies for these diseases.

The multiple roles of chronic stress and glucocorticoids in Alzheimer's disease pathogenesis

Chronic stress and the accompanying long-term elevation of glucocorticoids (GCs), the stress hormones of the body, increase the risk and accelerate the progression of Alzheimer's disease (AD). Signatures of AD include intracellular tau (MAPT) tangles, extracellular amyloid β (Aβ) plaques, and neuroinflammation. A growing body of work indicates that stress and GCs initiate cellular processes underlying these pathologies through dysregulation of protein homeostasis and trafficking, mitochondrial bioenergetics, and response to damage-associated stimuli. In this review, we integrate findings from mechanistic studies in rodent and cellular models, wherein defined chronic stress protocols or GC administration have been shown to elicit AD-related pathology. We specifically discuss the effects of chronic stress and GCs on tau pathogenesis, including hyperphosphorylation, aggregation, and spreading, amyloid precursor protein (APP) processing and trafficking culminating in Aβ production, immune priming by proinflammatory cytokines and disease-associated molecular patterns, and alterations to glial cell and blood-brain barrier (BBB) function.

METTL3 prevents granulosa cells mitophagy by regulating YTHDF2-mediated BNIP3 mRNA degradation due to arsenic exposure

The ovary is an important reproductive and endocrine organ for the continuation of the species and the homeostasis of the body's internal environment. Arsenic exposure is a global public health problem. However, the damage to the ovaries caused by exposure to arsenic-contaminated drinking water from neonatal mice period remains unclear. Here, we showed that arsenic exposure resulted in reduced granulosa cell proliferation, diminished ovarian reserve, decreased oogenesis, and endocrine disruption in mice. Mechanistically, arsenic exposure decreased the protein level of METTL3 in granulosa cells. The m6A modification levels of mitophagy regulated gene BNIP3 in 3'UTR region was decreased in arsenic exposed granulosa cells. Meanwhile, YTHDF2, which decays mRNA, bound to the 3'UTR region of BNIP3 was also decreased in arsenic exposed ovarian granulosa cells. Thus, BNIP3 mRNA becames more stable, and mitophagy was increased. The excessive mitophagy in granulosa cells led to endocrine disruption, follicular atresia and diminished ovarian reserve. In summary, our study reveals that METTL3-dependent m6A modification regulates granulosa cell mitophagy and follicular atresia by targeting BNIP3 which are induced by arsenic exposure.

Mitophagy-associated programmed neuronal death and neuroinflammation

Mitochondria are crucial organelles that play a central role in cellular metabolism and programmed cell death in eukaryotic cells. Mitochondrial autophagy (mitophagy) is a selective process where damaged mitochondria are encapsulated and degraded through autophagic mechanisms, ensuring the maintenance of both mitochondrial and cellular homeostasis. Excessive programmed cell death in neurons can result in functional impairments following cerebral ischemia and trauma, as well as in chronic neurodegenerative diseases, leading to irreversible declines in motor and cognitive functions. Neuroinflammation, an inflammatory response of the central nervous system to factors disrupting homeostasis, is a common feature across various neurological events, including ischemic, infectious, traumatic, and neurodegenerative conditions. Emerging research suggests that regulating autophagy may offer a promising therapeutic avenue for treating certain neurological diseases. Furthermore, existing literature indicates that various small molecule autophagy regulators have been tested in animal models and are linked to neurological disease outcomes. This review explores the role of mitophagy in programmed neuronal death and its connection to neuroinflammation.

Parkin, a Parkinson's disease-associated protein, mediates the mitophagy that plays a vital role in the pathophysiology of major depressive disorder

Depression is a complex mood disorder with multifactorial etiology and is also the most frequent non-motor symptom of Parkinson's disease. Emerging research suggests a potential link between mitochondrial dysfunction and the pathophysiology of major depressive disorder. By synthesizing current knowledge and research findings, this review sheds light on the intricate relationship between Parkin, a protein classically associated with Parkinson's disease, and mitochondrial quality control mechanisms (e.g., mitophagy, mitochondrial biogenesis, and mitochondrial dynamic), specifically focusing on their relevance in the context of depression. Additionally, the present review discusses therapeutic strategies targeting Parkin-medicated mitophagy and calls for further research in this field. These findings suggest promise for the development of novel depression treatments through modulating Parkin-mediated mitophagy.

The Potential Role of Artemisinins Against Neurodegenerative Diseases

Artemisinin (ART) and its derivatives, collectively referred to as artemisinins (ARTs), have been approved for the treatment of malaria for decades. ARTs are converted into dihydroartemisinin (DHA), the only active form, which is reductive in vivo. In this review, we provide a brief overview of the neuroprotective potential of ARTs and the underlying mechanisms on several of the most common neurodegenerative diseases, particularly considering their potential application in those associated with cognitive and motor impairments including Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), and amyotrophic lateral sclerosis (ALS). ARTs act as autophagy balancers to alleviate AD and PD. They inhibit neuroinflammatory responses by regulating phosphorylation of signal transduction proteins, such as AKT, PI3K, ERK, NF-κB, p38 MAPK, IκBα. In addition, ARTs regulate GABAergic signaling in a dose-dependent manner. Although they competitively inhibit the binding of gephyrin to GABAergic receptors, low doses of ARTs enhance GABAergic signaling. ARTs can also inhibit ferroptosis, activate the Akt/Bcl-2, AMPK, or ERK/CREB pathways to reduce oxidative stress, and maintain mitochondrial homeostasis, protecting neurons from oxidative stress injury. More importantly, ARTs structurally combine with and suppress β-Amyloid (A[Formula: see text]-induced neurotoxicity, reduce P-tau, and maintain O-GlcNAcylation/Phosphorylation balance, leading to relieved pathological changes in neurodegenerative diseases. Collectively, these natural properties endow ARTs with unique potential for application in neurodegenerative diseases.

Direct targets of MEF2C are enriched for genes associated with schizophrenia and cognitive function and are involved in neuron development and mitochondrial function

Myocyte Enhancer Factor 2C (MEF2C) is a transcription factor that plays a crucial role in neurogenesis and synapse development. Genetic studies have identified MEF2C as a gene that influences cognition and risk for neuropsychiatric disorders, including autism spectrum disorder (ASD) and schizophrenia (SCZ). Here, we investigated the involvement of MEF2C in these phenotypes using human-derived neural stem cells (NSCs) and glutamatergic induced neurons (iNs), which represented early and late neurodevelopmental stages. For these cellular models, MEF2C function had previously been disrupted, either by direct or indirect mutation, and gene expression assayed using RNA-seq. We integrated these RNA-seq data with MEF2C ChIP-seq data to identify dysregulated direct target genes of MEF2C in the NSCs and iNs models. Several MEF2C direct target gene-sets were enriched for SNP-based heritability for intelligence, educational attainment and SCZ, as well as being enriched for genes containing rare de novo mutations reported in ASD and/or developmental disorders. These gene-sets are enriched in both excitatory and inhibitory neurons in the prenatal and adult brain and are involved in a wide range of biological processes including neuron generation, differentiation and development, as well as mitochondrial function and energy production. We observed a trans expression quantitative trait locus (eQTL) effect of a single SNP at MEF2C (rs6893807, which is associated with IQ) on the expression of a target gene, BNIP3L. BNIP3L is a prioritized risk gene from the largest genome-wide association study of SCZ and has a function in mitophagy in mitochondria. Overall, our analysis reveals that either direct or indirect disruption of MEF2C dysregulates sets of genes that contain multiple alleles associated with SCZ risk and cognitive function and implicates neuron development and mitochondrial function in the etiology of these phenotypes.

ROS-mediated lysosomal membrane permeabilization and autophagy inhibition regulate bleomycin-induced cellular senescence

Bleomycin exhibits effective chemotherapeutic activity against multiple types of tumors, and also induces various side effects, such as pulmonary fibrosis and neuronal defects, which limit the clinical application of this drug. Macroautophagy/autophagy has been recently reported to be involved in the functions of bleomycin, and yet the mechanisms of their crosstalk remain insufficiently understood. Here, we demonstrated that reactive oxygen species (ROS) produced during bleomycin activation hampered autophagy flux by inducing lysosomal membrane permeabilization (LMP) and obstructing lysosomal degradation. Exhaustion of ROS with N-acetylcysteine relieved LMP and autophagy defects. Notably, we observed that LMP and autophagy blockage preceded the emergence of cellular senescence during bleomycin treatment. In addition, promoting or inhibiting autophagy-lysosome degradation alleviated or exacerbated the phenotypes of senescence, respectively. This suggests the alternation of autophagy activity is more a regulatory mechanism than a consequence of bleomycin-induced cellular senescence. Taken together, we reveal a specific role of bleomycin-induced ROS in mediating defects of autophagic degradation and further regulating cellular senescence in vitro and in vivo. Our findings, conversely, indicate the autophagy-lysosome degradation pathway as a target for modulating the functions of bleomycin. These provide a new perspective for optimizing bleomycin as a clinically applicable chemotherapeutics devoid of severe side-effects.Abbreviations: AT2 cells: type II alveolar epithelial cells; ATG7: autophagy related 7; bEnd.3: mouse brain microvascular endothelial cells; BNIP3L: BCL2/adenovirus E1B interacting protein 3-like; CCL2: C-C motif chemokine ligand 2; CDKN1A: cyclin dependent kinase inhibitor 1A; CDKN2A: cyclin dependent kinase inhibitor 2A; FTH1: ferritin heavy polypeptide 1; γ-H2AX: phosphorylated H2A.X variant histone; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; HUVEC: human umbilical vein endothelial cells; HT22: hippocampal neuronal cell lines; Il: interleukin; LAMP: lysosomal-associated membrane protein; LMP: lysosome membrane permeabilization; MTORC1: mechanistic target of rapamycin kinase complex 1; NAC: N-acetylcysteine; NCOA4: nuclear receptor coactivator 4; PI3K: phosphoinositide 3-kinase; ROS: reactive oxygen species; RPS6KB/S6K: ribosomal protein S6 kinase; SA-GLB1/β-gal: senescence-associated galactosidase, beta 1; SAHF: senescence-associated heterochromatic foci; SASP: senescence-associated secretory phenotype; SEC62: SEC62 homolog, preprotein translocation; SEP: superecliptic pHluorin; SQSTM1/p62: sequestosome 1; TFEB: transcription factor EB.

The interplay between mitophagy and mitochondrial ROS in acute lung injury

Mitochondria orchestrate the production of new mitochondria and the removal of damaged ones to dynamically maintain mitochondrial homeostasis through constant biogenesis and clearance mechanisms. Mitochondrial quality control particularly relies on mitophagy, defined as selective autophagy with mitochondria-targeting specificity. Most ROS are derived from mitochondria, and the physiological concentration of mitochondrial ROS (mtROS) is no longer considered a useless by-product, as it has been proven to participate in immune and autophagy pathway regulation. However, excessive mtROS appears to be a pathogenic factor in several diseases, including acute lung injury (ALI). The interplay between mitophagy and mtROS is complex and closely related to ALI. Here, we review the pathways of mitophagy, the intricate relationship between mitophagy and mtROS, the role of mtROS in the pathogenesis of ALI, and their effects and related progression in ALI induced by different conditions.

Diverse effects of synthetic glucocorticoid species on cell viability and stress response of neuroblastoma cells

Glucocorticoids (GCs) are widely used as powerful anti-inflammatory and immunosuppressive therapeutics in multiple pathological conditions. However, compelling evidence indicates that they might promote neurodegeneration by altering mitochondrial homeostatic processes. Although the effect of dexamethasone on cell survival and homeostasis has been widely investigated, the effect of other glucocorticoids needs to be explored in more detail. In this report, we have compared the neurotoxicity induced by dexamethasone, prednisolone, betamethasone, and hydrocortisone in cultured neuroblastoma cells, through the analysis of several parameters such as cell viability, ER stress, oxidative stress, and mitochondrial fusion and fission markers. Interestingly, we have found that synthetic glucocorticoids may impact neuronal viability by affecting different cellular responses, suggesting that their therapeutic use should be consciously decided after careful consideration of benefits and detrimental effects.

The therapeutic potential of traditional Chinese medicine in depression: focused on the modulation of neuroplasticity

Depression, a mood disorder characterized by a persistent low mood and lack of enjoyment, is considered the leading cause of non-fatal health losses worldwide. Neuroplasticity refers to the brain's ability to adapt to external or internal stimuli, resulting in functional and structural changes. This process plays a crucial role in the development of depression. Traditional Chinese Medicine (TCM) shows significant potential as a complementary and alternative therapy for neurological diseases, including depression. However, there has been no systematic summary of the role of neuroplasticity in the pathological development of depression and TCM Interventions currently. This review systematically summarized recent literature on changes in neuroplasticity in depression and analyzed the regulatory mechanisms of active metabolites in TCM and TCM formulas on neuroplasticity in antidepressant treatment. Additionally, this review discussed the limitations of current research and the application prospects of TCM in regulating neuroplasticity in antidepressant research.

Construction of a mitophagy-related prognostic signature for predicting prognosis and tumor microenvironment in lung adenocarcinoma

Background

Mitophagy is the selective degradation of mitochondria by autophagy. It becomes increasingly clear that mitophagy pathways are important for cancer cells to adapt to their high-energy needs. However, which genes associated with mitophagy could be used to prognosis cancer is unknown.

Methods

We created a clinical prognostic model using mitophagy-related genes (MRGs) in lung adenocarcinoma (LUAD) patients for the first time, and we employed bioinformatics methods to search for biomarkers that affect the progression and prognosis of LUAD. Transcriptome data for LUAD were obtained from The Cancer Genome Atlas (TCGA) database, and additional expression data from LUAD patients were sourced from the Gene Expression Omnibus (GEO) database. Furthermore, 25 complete MRGs were identified based on annotations from the MSigDB database.

Results

A comparison of the mitophagy scores between the groups with high and low scores was done using receiver operating characteristic (ROC) curves, which also revealed the differential gene expression patterns between the two groups. Using Kaplan-Meier analysis, two prognostic MRGs from the groups with high and low mitophagy scores were identified: TOMM40 and VDAC1. Using univariate and multivariate Cox regression, the relationship between the expression levels of these two genes and prognostic clinical features of LUAD was examined further.The prognosis of LUAD patients was shown to be significantly correlated (P < 0.05) with the expression levels of these two genes.

Conclusions

Our prognostic model would improve the prognosis of LUAD and guide clinical treatments.

Mitochondria in Aging and Alzheimer's Disease: Focus on Mitophagy

Alzheimer's disease (AD) is characterized by the accumulation of amyloid β and phosphorylated τ protein aggregates in the brain, which leads to the loss of neurons. Under the microscope, the function of mitochondria is uniquely primed to play a pivotal role in neuronal cell survival, energy metabolism, and cell death. Research studies indicate that mitochondrial dysfunction, excessive oxidative damage, and defective mitophagy in neurons are early indicators of AD. This review article summarizes the latest development of mitochondria in AD: 1) disease mechanism pathways, 2) the importance of mitochondria in neuronal functions, 3) metabolic pathways and functions, 4) the link between mitochondrial dysfunction and mitophagy mechanisms in AD, and 5) the development of potential mitochondrial-targeted therapeutics and interventions to treat patients with AD.

Amplifying hepatic L-aspartate levels suppresses CCl4-induced liver fibrosis by reversing glucocorticoid receptor β-mediated mitochondrial malfunction

Liver fibrosis is a determinant-stage process of many chronic liver diseases and affected over 7.9 billion populations worldwide with increasing demands of ideal therapeutic agents. Discovery of active molecules with anti-hepatic fibrosis efficacies presents the most attacking filed. Here, we revealed that hepatic L-aspartate levels were decreased in CCl4-induced fibrotic mice. Instead, supplementation of L-aspartate orally alleviated typical manifestations of liver injury and fibrosis. These therapeutic efficacies were alongside improvements of mitochondrial adaptive oxidation. Notably, treatment with L-aspartate rebalanced hepatic cholesterol-steroid metabolism and reduced the levels of liver-impairing metabolites, including corticosterone (CORT). Mechanistically, L-aspartate treatment efficiently reversed CORT-mediated glucocorticoid receptor β (GRβ) signaling activation and subsequent transcriptional suppression of the mitochondrial genome by directly binding to the mitochondrial genome. Knockout of GRβ ameliorated corticosterone-mediated mitochondrial dysfunction and hepatocyte damage which also weakened the improvements of L-aspartate in suppressing GRβ signaling. These data suggest that L-aspartate ameliorates hepatic fibrosis by suppressing GRβ signaling via rebalancing cholesterol-steroid metabolism, would be an ideal candidate for clinical liver fibrosis treatment.

Fusion-fission-mitophagy cycling and metabolic reprogramming coordinate nerve growth factor (NGF)-dependent neuronal differentiation

Neuronal differentiation is regulated by nerve growth factor (NGF) and other neurotrophins. We explored the impact of NGF on mitochondrial dynamics and metabolism through time-lapse imaging, metabolomics profiling, and computer modeling studies. We show that NGF may direct differentiation by stimulating fission, thereby causing selective mitochondrial network fragmentation and mitophagy, ultimately leading to increased mitochondrial quality and respiration. Then, we reconstructed the dynamic fusion-fission-mitophagy cycling of mitochondria in a computer model, integrating these processes into a single network mechanism. Both the computational model and the simulations are able to reproduce the proposed mechanism in terms of mitochondrial dynamics, levels of reactive oxygen species (ROS), mitophagy, and mitochondrial quality, thus providing a computational tool for the interpretation of the experimental data and for future studies aiming to detail further the action of NGF on mitochondrial processes. We also show that changes in these mitochondrial processes are intertwined with a metabolic function of NGF in differentiation: NGF directs a profound metabolic rearrangement involving glycolysis, TCA cycle, and the pentose phosphate pathway, altering the redox balance. This metabolic rewiring may ensure: (a) supply of both energy and building blocks for the anabolic processes needed for morphological reorganization, as well as (b) redox homeostasis.

18β-Glycyrrhetinic acid protects against deoxynivalenol-induced liver injury via modulating ferritinophagy and mitochondrial quality control

Deoxynivalenol (DON), a widespread mycotoxin, represents a substantial public health hazard due to its propensity to contaminate agricultural produce, leading to both acute and chronic health issues in humans and animals upon consumption. The role of ferroptosis in DON-induced hepatic damage remains largely unexplored. This study investigates the impact of 18β-glycyrrhetinic acid (GA), a prominent constituent of glycyrrhiza, on DON hepatotoxicity and elucidates the underlying mechanisms. Our results indicate that GA effectively attenuates liver injury inflicted by DON. This was achieved by inhibiting nuclear receptor coactivator 4 (NCOA4)-mediated ferritinophagy and ferroptosis, as well as by adjusting mitochondrial quality control (MQC). Specifically, GA curtails ferritinophagy by diminishing NCOA4 expression without affecting the autophagic flux. At a molecular level, GA binds to and stabilizes programmed cell death protein 4 (PDCD4), thereby inhibiting its ubiquitination and subsequent degradation. This stabilization of PDCD4 leads to the downregulation of NCOA4 via the JNK-Jun-NCOA4 axis. Knockdown of PDCD4 weakened GA's protective action against DON exposure. Furthermore, GA improved mitochondrial function and limited excessive mitophagy and mitochondrial division induced by DON. Disrupting GA's modulation of MQC nullified its anti-ferroptosis effects. Overall, GA offers protection against DON-induced ferroptosis by blocking ferritinophagy and managing MQC. ENVIRONMENTAL IMPLICATION: Food contamination from mycotoxins, is a problem for agricultural and food industries worldwide. Deoxynivalenol (DON), the most common mycotoxins in cereal commodities. A survey in 2023 showed that the positivity rate for DON contamination in food reached more than 70% globally. DON can damage the health of humans whether exposed to high doses for short periods of time or low doses for long periods of time. We have discovered 18β-Glycyrrhetinic acid (GA), a prominent constituent of glycyrrhiza. Liver damage caused by low-dose DON can be successfully treated with GA. This study will support the means of DON control, including antidotes.

RN0D, a galactoglucan from Panax notoginseng flower induces cancer cell death via PINK1/Parkin mitophagy

Metabolic alterations within mitochondria, encompassing processes such as autophagy and energy metabolism, play a pivotal role in facilitating the swift proliferation, invasion, and metastasis of cancer cells. Despite this, there is a scarcity of currently available medications with proven anticancer efficacy through the modulation of mitochondrial dysfunction in a clinical setting. Here, we introduce the structural characteristics of RN0D, a galactoglucan isolated and purified from Panax notoginseng flowers, mainly composed of β-1,4-galactan and β-1,3/1,6-glucan. RN0D demonstrates the capacity to induce mitochondrial impairment in cancer cells, leading to the accumulation of reactive oxygen species, initiation of mitophagy, and reduction in both mitochondrial number and size. This sequence of events ultimately results in the inhibition of mitochondrial and glycolytic bioenergetics, culminating in the demise of cancer cells due to adenosine triphosphate (ATP) deprivation. Notably, the observed bioactivity is attributed to RN0D's direct targeting of Galectin-3, as affirmed by surface plasmon resonance studies. Furthermore, RN0D is identified as an activator of the PTEN-induced kinase 1 (PINK1)/Parkin pathway, ultimately instigating cytotoxic mitophagy in tumor cells. This comprehensive study substantiates the rationale for advancing RN0D as a potentially efficacious anticancer therapeutic.

PGC-1a mediated mitochondrial biogenesis promotes recovery and survival of neuronal cells from cellular degeneration

Neurodegenerative disorders are characterized by the progressive loss of structure and function of neurons, often including the death of the neuron. Previously, we reported that, by removing the cell death stimulus, dying/injured neurons could survive and recover from the process of regulated cell death, even if the cells already displayed various signs of cellular damage. Now we investigated the role of mitochondrial dynamics (fission/fusion, biogenesis, mitophagy) in both degeneration and in recovery of neuronal cells. In neuronal PC12 cells, exposure to ethanol (EtOH) induced massive neurite loss along with widespread mitochondrial fragmentation, mitochondrial membrane potential loss, reduced ATP production, and decreased total mitochondrial volume. By removing EtOH timely all these mitochondrial parameters recovered to normal levels. Meanwhile, cells regrew neurites and survived. Study of the mitochondrial dynamics showed that autophagy was activated only during the cellular degeneration phase (EtOH treatment) but not in the recovery phase (EtOH removed), and it was not dependent on the Parkin/PINK1 mediated mitophagy pathway. Protein expression of key regulators of mitochondrial fission, phospho-Drp1Ser616 and S-OPA1, increased during EtOH treatment and recovered to normal levels after removing EtOH. In addition, the critical role of PGC-1α mediated mitochondrial biogenesis in cellular recovery was revealed: inhibition of PGC-1α using SR-18292 after EtOH removal significantly impeded recovery of mitochondrial damage, regeneration of neurites, and cell survival in a concentration-dependent manner. Taken together, our study showed reversibility of mitochondrial morphological and functional damage in stressed neuronal cells and revealed that PGC-1α mediated mitochondrial biogenesis played a critical role in the cellular recovery. This molecular mechanism could be a target for neuroprotection and neurorescue in neurodegenerative diseases.

Ubiquitinome Analysis Uncovers Alterations in Synaptic Proteins and Glucose Metabolism Enzymes in the Hippocampi of Adolescent Mice Following Cold Exposure

Cold exposure exerts negative effects on hippocampal nerve development in adolescent mice, but the underlying mechanisms are not fully understood. Given that ubiquitination is essential for neurodevelopmental processes, we attempted to investigate the effects of cold exposure on the hippocampus from the perspective of ubiquitination. By conducting a ubiquitinome analysis, we found that cold exposure caused changes in the ubiquitination levels of a variety of synaptic-associated proteins. We validated changes in postsynaptic density-95 (PSD-95) ubiquitination levels by immunoprecipitation, revealing reductions in both the K48 and K63 polyubiquitination levels of PSD-95. Golgi staining further demonstrated that cold exposure decreased the dendritic-spine density in the CA1 and CA3 regions of the hippocampus. Additionally, bioinformatics analysis revealed that differentially ubiquitinated proteins were enriched in the glycolytic, hypoxia-inducible factor-1 (HIF-1), and 5'-monophosphate (AMP)-activated protein kinase (AMPK) pathways. Protein expression analysis confirmed that cold exposure activated the mammalian target of rapamycin (mTOR)/HIF-1α pathway. We also observed suppression of pyruvate kinase M2 (PKM2) protein levels and the pyruvate kinase (PK) activity induced by cold exposure. Regarding oxidative phosphorylation, a dramatic decrease in mitochondrial respiratory-complex I activity was observed, along with reduced gene expression of the key subunits NADH: ubiquinone oxidoreductase core subunit V1 (Ndufv1) and Ndufv2. In summary, cold exposure negatively affects hippocampal neurodevelopment and causes abnormalities in energy homeostasis within the hippocampus.

Activation of innate immune receptor TLR9 by mitochondrial DNA plays essential roles in the chemical long-term depression of hippocampal neurons

Synaptic plasticity is believed to be the cellular basis for experience-dependent learning and memory. Although long-term depression (LTD), a form of synaptic plasticity, is caused by the activity-dependent reduction of cell surface α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA)-type glutamate receptors (AMPA receptors) at postsynaptic sites, its regulation by neuronal activity is not completely understood. In this study, we showed that the inhibition of toll-like receptor-9 (TLR9), an innate immune receptor, suppresses N-methyl-d-aspartate (NMDA)-induced reduction of cell surface AMPA receptors in cultured hippocampal neurons. We found that inhibition of TLR9 also blocked NMDA-induced activation of caspase-3, which plays an essential role in the induction of LTD. siRNA-based knockdown of TLR9 also suppressed the NMDA-induced reduction of cell surface AMPA receptors, although the scrambled RNA had no effect on the NMDA-induced trafficking of AMPA receptors. Overexpression of the siRNA-resistant form of TLR9 rescued the AMPA receptor trafficking abolished by siRNA. Furthermore, NMDA stimulation induced rapid mitochondrial morphological changes, mitophagy, and the binding of mitochondrial DNA (mtDNA) to TLR9. Treatment with dideoxycytidine and mitochondrial division inhibitor-1, which block mtDNA replication and mitophagy, respectively, inhibited NMDA-dependent AMPA receptor internalization. These results suggest that mitophagy induced by NMDA receptor activation releases mtDNA and activates TLR9, which plays an essential role in the trafficking of AMPA receptors during the induction of LTD.

Downregulation of VEGFA accelerates AGEs-mediated nucleus pulposus degeneration through inhibiting protective mitophagy in high glucose environments

Intervertebral disc degeneration (IVDD) contributes largely to low back pain. Recent studies have highlighted the exacerbating role of diabetes mellitus (DM) in IVDD, mainly due to the influence of hyperglycemia (HG) or the accumulation of advanced glycation end products (AGEs). Vascular endothelial growth factor A (VEGFA) newly assumed a distinct impact in nonvascular tissues through mitophagy regulation. However, the combined actions of HG and AGEs on IVDD and the involved role of VEGFA remain unclear. We confirmed the potential relation between VEGFA and DM through bioinformatics and biological specimen detection. Then we observed that AGEs induced nucleus pulposus (NP) cell degeneration by upregulating cellular reactive oxygen species (ROS), and HG further aggravated ROS level through breaking AGEs-induced protective mitophagy. Furthermore, this adverse effect could be strengthened by VEGFA knockdown. Importantly, we identified that the regulation of VEGFA and mitophagy were vital mechanisms in AGEs-HG-induced NP cell degeneration through Parkin/Akt/mTOR and AMPK/mTOR pathway. Additionally, VEGFA overexpression through local injection with lentivirus carrying VEGFA plasmids significantly alleviated NP degeneration and IVDD in STZ-induced diabetes and puncture rat models. In conclusion, the findings first confirmed that VEGFA protects against AGEs-HG-induced IVDD, which may represent a therapeutic strategy for DM-related IVDD.

LncRNA LBX2-AS1 promotes proliferation and migratory capacity of clear cell renal cell carcinoma through mitophagy

BACKGROUND

Long non-coding RNAs (lncRNAs) have been extensively investigated in the field of cancer, among which, lncRNA ladybird homeobox 2-antisense RNA 1 (LBX2-AS1) has been demonstrated to exert carcinogenic effects on a variety of malignancies. However, the biological functions of LBX2-AS1 in clear cell renal cell carcinoma (ccRCC) have not been explicitly elucidated.

METHODS

Arraystar lncRNA chip and qRT-PCR verify the expression of LncRNA LBX2-AS1 in ccRCC. CCK-8 assay and cell cloning assay were used to assess the proliferative capacity of ccRCC cells. Migration abilities were quantified by scratch assay and transwell assay. Potential molecular signaling pathways were determined by high-throughput whole transcriptomics analysis. WB analysis was performed to validate the relationship between LBX2-AS1 and key molecules of mitophagy pathway. The effect of LBX2-AS1 on mitophagy was observed by laser confocal microscopy. Rescue experiments further validated the role of downstream gene FOXO3A in the LBX2-AS1 signaling pathway. Finally, the authentic effect of LBX2-AS1 was verified in vivo.

RESULTS

LncRNA LBX2-AS1 was over expressed in ccRCC tissues and could enhance the proliferation and migration of ccRCC cells. Autophagic pathway was identified as a possible mechanism involved in the oncogenic effect of LBX2-AS1. Mitophagy levels were observed in LBX2-AS1 low-expressing cells through laser confocal microscopy. Knockdown of LBX2-AS1 significantly elevated mitophagy levels as observed using laser confocal microscopy and led to FOXOA3 decreasing in and BNIP3L and LC3 enrichment. Meanwhile, LBX2-AS1 knocking down dampened the proliferation of ccRCC cells in vivo.

Mitochondria in depression: The dysfunction of mitochondrial energy metabolism and quality control systems

BACKGROUND

Depression is the most disabling neuropsychiatric disorder, causing difficulties in daily life activities and social interactions. The exact mechanisms of depression remain largely unclear. However, some studies have shown that mitochondrial dysfunction would play a crucial role in the occurrence and development of depression.

AIMS

To summarize the known knowledge about the role of mitochondrial dysfunction in the pathogenesis of depression.

METHODS

We review the recent literature， including 105 articles, to summarize the mitochondrial energy metabolism and quality control systems in the occurrence and development of depression. Some antidepressants which may exert their effects by improving mitochondrial function are also discussed.

RESULTS

Impaired brain energy metabolism and (or) damaged mitochondrial quality control systems have been reported not only in depression patients but in animal models of depression. Although the classical antidepressants have not been specially designed to target mitochondria, the evidence suggests that many antidepressants may exert their effects by improving mitochondrial function.

CONCLUSIONS

This brief review focuses on the findings that implicate mitochondrial dysfunction and the quality control systems as important etiological factors in the context of depressive disorders. It will help us to understand the various concepts of mitochondrial dysfunction in the pathogenesis of depression, and to explore novel and more targeted therapeutic approaches for depression.

Advancements in the study of synaptic plasticity and mitochondrial autophagy relationship

Synapses serve as the points of communication between neurons, consisting primarily of three components: the presynaptic membrane, synaptic cleft, and postsynaptic membrane. They transmit signals through the release and reception of neurotransmitters. Synaptic plasticity, the ability of synapses to undergo structural and functional changes, is influenced by proteins such as growth-associated proteins, synaptic vesicle proteins, postsynaptic density proteins, and neurotrophic growth factors. Furthermore, maintaining synaptic plasticity consumes more than half of the brain's energy, with a significant portion of this energy originating from ATP generated through mitochondrial energy metabolism. Consequently, the quantity, distribution, transport, and function of mitochondria impact the stability of brain energy metabolism, thereby participating in the regulation of fundamental processes in synaptic plasticity, including neuronal differentiation, neurite outgrowth, synapse formation, and neurotransmitter release. This article provides a comprehensive overview of the proteins associated with presynaptic plasticity, postsynaptic plasticity, and common factors between the two, as well as the relationship between mitochondrial energy metabolism and synaptic plasticity.

Functional properties of ATPIF1 in the orange-spotted grouper (Epinephelus coioides) in response to viral infection

ATP synthase inhibitory factor 1 (ATPIF1) can activate mitochondrial autophagic pathway and mediates immune response by regulating ATP synthase activity. However, the role of fish ATPIF1 on viral infection is still unknown. In this study, we identified an ATPIF1 homolog (Ec-ATPIF1) from orange-spotted grouper (Epinephelus coioides). Ec-ATPIF1 is mainly expressed in the kidney and liver. The expression of Ec-ATPIF1 was significantly up-regulated after RGNNV stimulation in vitro. Further experiments showed that overexpression of Ec-ATPIF1 inhibited the expression of viral genes (CP and RdRp) and intracellular ATP synthesis. Ec-ATPIF1 overexpression also promoted the expression of mitophagy related genes (PINK1, Parkin, BNIP3, NIX, FUNDC1, LC3), inflammation-related factors (IL-1β, IL-6, IL-8, IL-10, TNF-α, TLR2) and interferon pathway factors (IRF1, IRF3, IRF7, MX1, ISG15, ISG56, MDA5, TRIF). While the knockdown of Ec-ATPIF1 exhibited the opposite effects on the expression of viral genes and immune-related factors above. These data suggest that Ec-ATPIF1 can impact viral infection by regulating mitophagy, ATP synthesis, the expression of inflammatory factors and interferon pathway factors. These findings will be beneficial to better explore the immune regulatory mechanisms of fish respond to viral infection.

Dapagliflozin improves diabetic cognitive impairment via indirectly modulating the mitochondria homeostasis of hippocampus in diabetic mice

Cognitive impairment is increasingly recognized as an important comorbidity of diabetes progression; however, the underlying molecular mechanism is unclear. Dapagliflozin, an inhibitor of sodium-glucose co-transporter 2 (SGLT2), has shown promising effects against diabetes in rodent experiments and human clinical assays. This study aimed to determine the underlying mechanism and examine the effect of dapagliflozin on diabetic cognitive impairment. To create an in vivo model of diabetic cognitive impairment, streptozotocin (STZ)-induced diabetic mice were used. Dapagliflozin was administered to mice for 8 weeks. The context fear condition and Morris water maze test was used to evaluate mice's behavioral change. Western blotting was used to evaluate protein expression. Hematoxylin and eosin (HE) and Nissl staining were applied to monitor morphological and structural changes. Congo red staining was performed to identify the formation of senile plaques. Mitochondria morphology was examined using a transmission electron microscope, and blood flow in the mouse cerebral cortex was measured using a laser Doppler imaging assay. Comparison to the diabetes mellitus (DM) group, the dapagliflozin group had lower glucose levels. Behavioral studies have shown that dapagliflozin can restore memory deficits in diabetic mice. The murky cell membrane edges and Nissl bodies more difficult to identify in the DM group were revealed by HE and Nissl staining, which were both improved by dapagliflozin treatment. Dapagliflozin inhibited the progression of Aβ generation and the reduced cerebral blood flow in the DM group was rescued. After dapagliflozin treatment, damaged mitochondria and lack of SGLT2 in the hippocampus and cortex of diabetic mice were repaired. Diabetes-induced cognitive dysfunction was attenuated by dapagliflozin and the effect was indirect rather than direct.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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