Involvement of PGC-1α in the formation and maintenance of neuronal dendritic spines

Regulating peroxisome proliferator activated receptor gamma coactivator-1alpha (PGC-1α): A potential role in neurological disorder and treatment

Neurological disorders are catastrophic and challenging conditions that affect central nervous system. They constitute a major health problem worldwide and place a huge economic burden on society and individuals. Extensive evidence has shown that peroxisome proliferator-activated receptor gamma coactivator-1alpha (PGC-1α) is an essential macromolecule that could be targeted to ameliorate the pathology of neurological disorders. This review is the first to summarize studies that have used therapeutics targeted to influence PGC-1α transcription and/or protein abundance/stability to treat neurological diseases. Moreover, the therapeutic target role of PGC-1α has been clarified in neurological disorders from the potential therapeutic agent that targets PGC-1α, for example, chemical agents, proteins and peptides, nucleic acids, and natural extracts. The scientific evidence summarized in this review demonstrates that targeting PGC-1α is an effective strategy for the treatment of neurological disorders. Moreover, PGC-1α could be used as a target to screen or discover new safe and effective natural products, chemical compounds, nucleic acids, or proteins for treating neurological disorders. This review provides new insights that targeting PGC-1α is an efficient strategy for the therapy of neurological disorders and providing key protein target for developing and screening new, safe, and effective PGC-1α agonists against neurological disorders.

The effects of risperidone and voluntary exercise intervention on synaptic plasticity gene expressions in the hippocampus and prefrontal cortex of juvenile female rats

BACKGROUND

Psychiatric disorders and antipsychotics are associated with impaired neuroplasticity, while physical exercise has been reported to enhance neuroplasticity and improve cognitive and affective processes. Therefore, this study hypothesizes that voluntary exercise can enhance synaptic plasticity in juvenile rats disrupted by risperidone, a commonly prescribed antipsychotic for pediatric patients.

METHODS

Thirty-two juvenile female rats were randomly assigned to Vehicle+Sedentary, Risperidone (0.9mg/kg; b.i.d)+Sedentary, Vehicle+Exercise (three hours daily access to running wheels), and Risperidone+Exercise groups for four week treatment. Brains were collected for further analysis.

RESULTS

In the hippocampus, the mRNA expressions of Bdnf, Ntrk2, and Grin2b were increased by risperidone and exercise intervention. Exercise upregulated expression of Grin1 and Grin2a. Syn1 and Syp mRNA expression were enhanced by exercise in the risperidone-treated group. The expression of both Mfn1 and Drp1 mRNA were decreased by risperidone-only treatment. In the prefrontal cortex, Bdnf and Dlg4 expression was upregulated by exercise, while the Ntrk2 expression was reduced by risperidone and reversed by exercise. The Mfn1 mRNA expression was decreased by risperidone with or without voluntary exercise. The risperidone-decreased Ppargc1α gene expression was enhanced by exercise.

CONCLUSION

Risperidone affects synaptic plasticity through a complex mechanism in female juvenile rats: enhancing certain key genes in the hippocampus while inhibiting genes essential for mitochondrial function. In line with our hypothesis, voluntary exercise promotes genes beneficial for synaptic plasticity and enhances specific genes reduced by risperidone, in female juvenile rats.

Withania somnifera Regulates Mitochondrial Biogenesis and Energetics in Rat Cortical Neurons: Role of BDNF and SIRT1

Withania somnifera, a psychoactive plant with putative neuroprotective actions, is used in Indian traditional medicine for the treatment of neuropsychiatric and neurodegenerative disorders. However, the key mechanisms underlying the pleiotropic actions of Withania somnifera on the nervous system remain poorly understood. Given converging evidence suggests a critical role for mitochondrial dysfunction in the pathophysiology of neuropsychiatric and neurodegenerative diseases, we hypothesized that Withania somnifera may exert pleiotropic effects via targeting mitochondria. Treatment with Withania somnifera root extract (RE) or the withanolide-withanoside rich fraction (WLS) enhanced cellular ATP levels in rat cortical neurons in vitro and in the neocortex in vivo. In vivo respirometry performed on mitochondria isolated from the neocortex following RE or WLS treatment revealed increased mitochondrial respiration and OxPhos efficiency. Furthermore, WLS treatment evoked increases in mitochondrial mass, and RE and WLS treatments enhanced expression of brain derived neurotrophic factor (BDNF) and Sirtuin 1 (SIRT1), both in vitro and in vivo. Pharmacological inhibitor studies support an important role for BDNF and SIRT1 in the mitochondrial effects of Withania somnifera. Experiments with distinct phytochemical components of WLS identified withanolide A and withanoside IV as key constituents that enhance mitochondrial biogenesis and neuroenergetics. The neuroprotective actions of WLS, withanolide A and withanoside IV against corticosterone-induced neuronal cell death in vitro, required signaling via BDNF and SIRT1. Collectively, these results indicate that Withania somnifera root extract and specific phytochemical constituents robustly influence mitochondria in cortical neurons, contributing to stress adaptation and neuroprotection via BDNF and SIRT1 signaling.

Antioxidant and Anti-Inflammatory Defenses in Huntington's Disease: Roles of NRF2 and PGC-1α, and Therapeutic Strategies

Huntington's disease (HD) is a detrimental neurodegenerative disease caused by the expansion of a CAG triplet in the HTT gene. This mutation leads to the production of mutant Huntingtin (Htt) protein with toxic gain-of-function. The mHtt is responsible in several ways for the establishment of an intricate pathogenetic scenario in affected cells, particularly in HD neurons. Among the features of HD, oxidative stress plays a relevant role in the progression of the disease at the cellular level. Mitochondrial dysfunction, bioenergetic deficits, Reactive Oxygen Species (ROS) production, neuroinflammation, and general reduction of antioxidant levels are all involved in the promotion of a toxic oxidative environment, eventually causing cell death. Nonetheless, neuronal cells exert antioxidant molecules to build up defense mechanisms. Key components of these defensive mechanisms are the nuclear factor erythroid 2-related factor 2 (NRF2) and peroxisome proliferator-activated receptor gamma coactivator-1 α (PGC-1α). Thus, this review aims to describe the involvement of oxidative stress in HD by exploring the roles of NRF2 and PGC-1α, crucial actors in this play. Finally, antioxidant therapeutic strategies targeting such markers are discussed.

Cognitive impairment following maternal separation in rats mediated by the NAD+/SIRT3 axis via modulation of hippocampal synaptic plasticity

Maternal separation (MS) during early life can induce behaviors in adult animals that resemble those seen in schizophrenia, manifesting cognitive deficits. These cognitive deficits may be indicative of oxidative stress linked to mitochondrial dysfunction. However, there is limited understanding of the molecular mechanisms regulating mitochondria in neural circuits that govern cognitive impairment relevant to schizophrenia, and their impact on neuronal structure and function. A 24-h MS rat model was utilized to simulate features associated with schizophrenia. Schizophrenia-associated behaviors and cognitive impairment were assessed using the open field test, pre-pulse inhibition, novel object recognition test, and Barnes maze test. The levels of mitochondrial proteins were measured using western blot analysis. Additionally, alterations in mitochondrial morphology, reduced hippocampal neuronal spine density, and impaired LTP in the hippocampus were observed. Nicotinamide (NAM) supplementation, administration of honokiol (HNK) (a SIRT3 activator), or overexpression of SIRT3 could inhibit cognitive deficits and cellular dysfunction. Conversely, administration of 3-TYP (a SIRT3 inhibitor) or knocking down SIRT3 expression in control rats led to deficits in behavioral and hippocampal neuronal phenotype. Our results suggest a causal role for the NAD+/SIRT3 axis in modulating cognitive behaviors via effects on hippocampal neuronal synaptic plasticity. The NAD+/SIRT3 axis could be a promising therapeutic target for addressing cognitive dysfunctions, such as those seen in schizophrenia.

Neuron-specific isoform of PGC-1α regulates neuronal metabolism and brain aging

The brain is a high-energy tissue, and although aging is associated with dysfunctional inflammatory and neuron-specific functional pathways, a direct connection to metabolism is not established. Here, we show that isoforms of mitochondrial regulator PGC-1α are driven from distinct brain cell-type specific promotors, repressed with aging, and integral in coordinating metabolism and growth signaling. Transcriptional and proteomic profiles of cortex from male adult, middle age, and advanced age mice reveal an aging metabolic signature linked to PGC-1α. In primary culture, a neuron-exclusive promoter produces the functionally dominant isoform of PGC-1α. Using growth repression as a challenge, we find that PGC-1α is regulated downstream of GSK3β independently across promoters. Broad cellular metabolic consequences of growth inhibition observed in vitro are mirrored in vivo, including activation of PGC-1α directed programs and suppression of aging pathways. These data place PGC-1α centrally in a growth and metabolism network directly relevant to brain aging.

Study insights in the role of PGC-1α in neurological diseases: mechanisms and therapeutic potential

Peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α), which is highly expressed in the central nervous system, is known to be involved in the regulation of mitochondrial biosynthesis, metabolic regulation, neuroinflammation, autophagy, and oxidative stress. This knowledge indicates a potential role of PGC-1α in a wide range of functions associated with neurological diseases. There is emerging evidence indicating a protective role of PGC-1α in the pathogenesis of several neurological diseases. As such, a deeper and broader understanding of PGC-1α and its role in neurological diseases is urgently needed. The present review provides a relatively complete overview of the current knowledge on PGC-1α, including its functions in different types of neurons, basic structural characteristics, and its interacting transcription factors. Furthermore, we present the role of PGC-1α in the pathogenesis of various neurological diseases, such as intracerebral hemorrhage, ischemic stroke, Alzheimer's disease, Parkinson's disease, Amyotrophic lateral sclerosis, Huntington's disease, and other PolyQ diseases. Importantly, we discuss some compounds or drug-targeting strategies that have been studied to ameliorate the pathology of these neurological diseases and introduce the possible mechanistic pathways. Based on the available studies, we propose that targeting PGC-1α could serve as a promising novel therapeutic strategy for one or more neurological diseases.

Unveiling new perspectives about the onset of neurological and cognitive deficits in cerebral malaria: exploring cellular and neurochemical mechanisms

Cerebral malaria is the most severe and lethal complication caused by Plasmodium falciparum infection, leading to critical neurological impairments and long-term cognitive, behavioral, and neurological sequelae in survivors, particularly affecting children under the age of five. Various hypotheses have been proposed to explain the neurological syndrome associated to cerebral malaria condition, including vascular occlusion and sequestration, cytokine storm or inflammatory response, or a combination of these mechanisms and despite extensive research and a growing range of scientific information, the precise pathophysiological mechanism remains poorly understood. In this sense, this review aims to explore the neurological impairment in cerebral malaria and elucidate novel mechanisms to explain the severity of this disease. Recent evidence implicates glutamate and glutamatergic pathways in the onset of cerebral malaria, alongside the impairments in the metabolic activity of other molecules such as dopamine and kynurenic acid. These neurotransmitters pathways may play a crucial role in the pathogenesis of cerebral malaria, potentially interacting with other molecular players. By enhancing our understanding in the pathophysiology of cerebral malaria, this article seeks to explore new hypotheses regarding the involvement of neurotransmitters and their interactions with other molecular targets, thereby contributing to the overall pathology of cerebral malaria.

BDNF-TrkB Signaling in Mitochondria: Implications for Neurodegenerative Diseases

Brain-derived neurotrophic factor (BDNF) plays a pivotal role in neuronal development, synaptic plasticity, and overall neuronal health by binding to its receptor, tyrosine receptor kinase B (TrkB). This review delves into the intricate mechanisms through which BDNF-TrkB signaling influences mitochondrial function and potentially influences pathology in neurodegenerative diseases. This review highlights the BDNF-TrkB signaling pathway which regulates mitochondrial bioenergetics, biogenesis, and dynamics, mitochondrial processes vital for synaptic transmission and plasticity. Furthermore, we explore how the BDNF-TrkB-PKA signaling in the cytosol and in mitochondria affects mitochondrial transport and distribution and mitochondrial content, which is crucial for supporting the energy demands of synapses. The dysregulation of this signaling pathway is linked to various neurodegenerative diseases, including Alzheimer's and Parkinson's disease, which are characterized by mitochondrial dysfunction and reduced BDNF expression. By examining seminal studies that have characterized this signaling pathway in health and disease, the present review underscores the potential of enhancing BDNF-TrkB signaling to mitigate mitochondrial dysfunction in neurodegenerative diseases, offering insights into therapeutic strategies to enhance neuronal resilience and function.

Study on the role of Dihuang Yinzi in regulating the AMPK/SIRT1/PGC-1α pathway to promote mitochondrial biogenesis and improve Alzheimer's disease

ETHNOPHARMACOLOGICAL RELEVANCE

Dihuang Yinzi (DHYZ) is a classic prescription in traditional Chinese medicine. Its therapeutic effect on Alzheimer's disease (AD) has been widely validated. However, the underlying molecular mechanisms of DHYZ in AD treatment remain unclear and require further research.

AIM OF THE STUDY

Elucidating DHYZ's promotion of mitochondrial biogenesis through the AMPK/SIRT1/PGC-1α pathway improves neuronal loss, mitochondrial damage, and memory deficits in AD.

MATERIALS AND METHODS

Administering DHYZ by gavage to SAMP8 mice, after completing behavioral tests, the effects of DHYZ on hippocampal neuron loss and mitochondrial structural damage in AD model mice were assessed using Nissl staining and transmission electron microscopy. Western blot was used to detect the expression of mitochondrial biogenesis-related proteins PGC-1α, CREB, mitochondrial fusion protein MFN2, and mitochondrial fission proteins DRP1 and FIS1. At the same time, immunofluorescence (IF) was employed to measure the relative fluorescence intensity of mitochondrial fusion protein MFN1. After determining the optimal dose of DYHZ for treating AD, we conducted mechanistic studies. By intraperitoneally injecting SAMP8 mice with the AMPK inhibitor (Compound C) to inhibit AMPK protein expression and subsequently treating them with DHYZ, the impact of DHYZ on hippocampal neurons in AD model mice was evaluated using Nissl and hematoxylin-eosin staining. Western blot was used to detect the protein expression of AMPK, p-AMPK, SIRT1, PGC-1α, NRF1, and TFAM. In contrast, IF was used to measure the relative fluorescence intensity of PGC-1α, NRF1, and TFAM proteins in the hippocampal CA1 region.

RESULTS

DHYZ significantly improved AD model mice's cognitive impairment and memory deficits and mitigated hippocampal neuron loss and degeneration. Additionally, it ameliorated mitochondrial morphological structures. DHYZ upregulated the protein expression of mitochondrial biogenesis-related proteins PGC-1α, CREB, and mitochondrial fusion proteins MFN1 and MFN2 while inhibiting the expression of mitochondrial fission proteins DRP1 and FIS1. Further studies revealed that DHYZ could upregulate the expression of the AMPK/SIRT1/PGC-1α pathway proteins and their downstream proteins NRF1 and TFAM.

CONCLUSION

DHYZ promotes mitochondrial biogenesis by activating the AMPK/SIRT1/PGC-1α signaling pathway, thereby improving memory deficits, neuronal loss, and mitochondrial dysfunction in AD.

The E3-ligase Siah2 activates mitochondrial quality control in neurons to maintain energy metabolism during ischemic brain tolerance

Mitochondrial quality control is crucial for the homeostasis of the mitochondrial network. The balance between mitophagy and biogenesis is needed to reduce cerebral ischemia-induced cell death. Ischemic preconditioning (IPC) represents an adaptation mechanism of CNS that increases tolerance to lethal cerebral ischemia. It has been demonstrated that hypoxia-induced Seven in absentia Homolog 2 (Siah2) E3-ligase activation influences mitochondrial dynamics promoting the degradation of mitochondrial proteins. Therefore, in the present study, we investigated the role of Siah2 in the IPC-induced neuroprotection in in vitro and in vivo models of IPC. To this aim, cortical neurons were exposed to 30-min oxygen and glucose deprivation (OGD, sublethal insult) followed by 3 h OGD plus reoxygenation (lethal insult). Our results revealed that the mitochondrial depolarization induced by hypoxia activates Siah2 at the mitochondrial level and increases LC3-II protein expression, a marker of mitophagy, an effect counteracted by the reoxygenation phase. By contrast, hypoxia reduced the expression of peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), a marker of mitochondrial biogenesis, whereas its expression was increased after reoxygenation thus improving mitochondrial membrane potential, mitochondrial calcium content, and mitochondrial morphology, hence leading to neuroprotection in IPC. Furthermore, Siah2 silencing confirmed these results. Collectively, these findings indicate that the balance between mitophagy and mitochondrial biogenesis, due to the activation of the Siah2-E3-ligase, might play a role in IPC-induced neuroprotection.

Reversal of neuronal tau pathology via adiponectin receptor activation

Changes in brain mitochondrial metabolism are coincident with functional decline; however, direct links between the two have not been established. Here, we show that mitochondrial targeting via the adiponectin receptor activator AdipoRon (AR) clears neurofibrillary tangles (NFTs) and rescues neuronal tauopathy-associated defects. AR reduced levels of phospho-tau and lowered NFT burden by a mechanism involving the energy-sensing kinase AMPK and the growth-sensing kinase GSK3b. The transcriptional response to AR included broad metabolic and functional pathways. Induction of lysosomal pathways involved activation of LC3 and p62, and restoration of neuronal outgrowth required the stress-responsive kinase JNK. Negative consequences of NFTs on mitochondrial activity, ATP production, and lipid stores were corrected. Defects in electrophysiological measures (e.g., resting potential, resistance, spiking profiles) were also corrected. These findings reveal a network linking mitochondrial function, cellular maintenance processes, and electrical aspects of neuronal function that can be targeted via adiponectin receptor activation.

Mechanisms of time-restricted feeding-induced neuroprotection and neuronal plasticity in ischemic stroke as a function of circadian rhythm

Time-restricted feeding (TRF) is known to promote longevity and brain function, and potentially prevent neurological diseases. Animal studies show that TRF enhances brain-derived neurotrophic factor (BDNF) signaling and regulates autophagy and neuroinflammation, supporting synaptic plasticity, neurogenesis and neuroprotection. Feeding/fasting paradigms influence the circadian cycle, with TRF aligning circadian cycle-related gene expression, and thus altering physiological processes. Emerging evidence highlights the role of gut microbiota in neuronal plasticity, based on the observation that TRF significantly alters gut microbiota composition. Hence, the gut-brain axis may be crucial for maintaining cognitive functions and presents a potential therapeutic target for TRF-mediated neuroprotection. In the context of ischemic stroke where neuronal damage is extensive, TRF can be a preconditioning strategy to enhance synaptic plasticity and neuronal resilience, thus improving outcomes after stroke. This review discussed the link between TRF and circadian regulation in neuronal plasticity and its implications for recovery after stroke.

Consequences of Early Maternal Deprivation on Neuroinflammation and Mitochondrial Dynamics in the Central Nervous System of Male and Female Rats

Early life stress (ELS) is associated with an increased risk for neuropsychiatric disorders, and both neuroinflammation and mitochondrial dysfunction seem to be central to mental health. Herein, using an animal model of ELS, a single episode of maternal deprivation (MD, 24 h on pnd 9) extensively documented to elicit behavioural anomalies in male and female Wistar rats, we investigated its consequences in terms of neuroinflammation and mitochondrial dynamics in the prefrontal cortex (PFC) and the hippocampal formation (HCF). MD differentially affected the brain content of cytokines: MD induced a transient increase in pro-inflammatory cytokines (IL-1β and IL-6) in the PFC, as well as in the levels of the anti-inflammatory cytokine IL-10 in the HCF. MD also induced a significant decrease mitochondria citrate synthase activity, but MD did not exert significant changes in mitochondria Complex IV activity, revealing a generalized decrease in mitochondrial density without any change in mitochondrial respiration. In the present study, we demonstrate that MD induces neuroinflammatory processes in specific brain regions. Additional research is needed to better understand the temporal pattern of such changes, their impact on the developing brain, and their participation in the already well-known behavioural consequences of MD.

The catabolic - anabolic cycling hormesis model of health and resilience

A major goal of aging research is to identify ways of extending productive and disease-free lifespans. Here we present the catabolic - anabolic cycling hormesis (CACH) model for optimizing health. The CACH model is based on the concept that cells and organ systems respond to catabolic challenges in ways that bolster their resilience and that an anabolic recovery period is required to effectuate the benefits of the catabolic challenge. As two prominent real-world examples we highlight the literature on the molecular and cellular mechanisms by which physical exercise and intermittent fasting bolster cellular and organismal performance and resilience, and suppress disease processes. Over periods of weeks and months the CACH of exercise and fasting promote optimal health. The hormesis concept is integral to the CACH model and predicts an upper limit to the beneficial effects of catabolic - anabolic cycling that reflects a limit of biological plasticity. This paper extends the hormesis model of health by proposing that 1) it is comprised of two complementary phases: catabolic (adaptive stress responses and conservation of resources) and anabolic (growth and plasticity) and, 2) that CACH is metabolically integrated, quantitatively flexible and dynamically regulated. This model has important implications for future basic and translational research in the fields of aging and related disease processes.

Effects of Caloric Restriction and Intermittent Fasting and Their Combined Exercise on Cognitive Functioning: A Review

PURPOSE OF REVIEW

The impact of dietary habits on cognitive function is increasingly gaining attention. The review is to discuss how caloric restriction (CR) and intermittent fasting (IF) can enhance cognitive function in healthy states through multiple pathways that interact with one another. Secondly, to explore the effects of CR and IF on cognitive function in conditions of neurodegenerative diseases, obesity diabetes and aging, as well as potential synergistic effects in combination with exercise to prevent cognitively related neurodegenerative diseases.

RECENT FINDINGS

With age, the human brain ages and develops corresponding neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, and epilepsy, which in turn trigger cognitive impairment. Recent research indicates that the impact of diet and exercise on cognitive function is increasingly gaining attention. The benefits of exercise for cognitive function and brain plasticity are numerous, and future research can examine the efficacy of particular dietary regimens during physical activity when combined with diet which can prevent cognitive decline.

Effect of bioactive extracts from Eucalyptus globulus leaves in experimental models of Alzheimer's disease

Current therapies for Alzheimer's disease (AD) do not delay its progression, therefore, novel disease-modifying strategies are urgently needed. Recently, an increasing number of compounds from natural origin with protective properties against AD have been identified. Mixtures or extracts obtained from natural products containing several bioactive compounds have multifunctional properties and have drawn the attention because multiple AD pathways can be simultaneously modulated. This study evaluated the in vitro and in vivo effect of the essential oil (EO) obtained from the hydrodistillation of Eucalyptus globulus leaves, and an extract obtained from the hydrodistillation residual water (HRW). It was observed that EO and HRW have anti-inflammatory effect in brain immune cells modeling AD, namely lipopolysaccharide (LPS)- and amyloid-beta (Aβ)-stimulated microglia. In cell models that mimic AD-related neuronal dysfunction, HRW attenuated Aβ secretion and Aβ-induced mitochondrial dysfunction. Since the HRW's major components did not cross the blood-brain barrier, both EO and HRW were administered to the APP/PS1 transgenic AD mouse model by an intranasal route, which reduced cortical and hippocampal Aβ levels, and to rescue memory deficits and anxiety-like behaviors. Finally, HRW and EO were found to regulate cholesterol levels in aged mice after intranasal administration, suggesting that these extracts can reduce hypercholesterolemia and avoid risk for AD development. Overall, findings support a protective role of E. globulus extracts against AD‑like pathology and cognitive impairment highlighting the underlying mechanisms. These extracts obtained from underused forest biomass could be useful to develop nutraceutical supplements helpful to avoid AD risk and to prevent its progression.

Impact of Physical Activity on Cellular Metabolism Across Both Neurodegenerative and General Neurological Conditions: A Narrative Review

BACKGROUND

Regular physical activity plays a crucial role in modulating cellular metabolism and mitigating the progression of neurodegenerative diseases such as Alzheimer's, Parkinson's, and Multiple Sclerosis.

OBJECTIVE

The objective of this review is to evaluate the molecular mechanisms by which exercise influences cellular metabolism, with a focus on its potential as a therapeutic intervention for neurological disorders.

METHODS

A comprehensive literature review was conducted using peer-reviewed scientific articles, with a focus on the period between 2015 and 2024, to analyze the effects of exercise on mitochondrial function, oxidative stress, and metabolic health.

RESULTS

The findings indicate that exercise promotes mitochondrial biogenesis, enhances oxidative phosphorylation, and reduces reactive oxygen species, contributing to improved energy production and cellular resilience. These metabolic adaptations are associated with delayed disease progression and reduced symptoms in patients with neurodegenerative conditions. Additionally, integrating exercise with nutritional strategies may further enhance therapeutic outcomes by addressing metabolic disturbances comprehensively.

CONCLUSIONS

This review concludes that personalized exercise protocols should be developed to optimize metabolic benefits for patients with neurological diseases, while future research should focus on biomarker development for individualized treatment approaches. These findings highlight the importance of non-pharmacological interventions in managing neurodegenerative diseases.

Unraveling the role and mechanism of mitochondria in postoperative cognitive dysfunction: a narrative review

Postoperative cognitive dysfunction (POCD) is a frequent neurological complication encountered during the perioperative period with unclear mechanisms and no effective treatments. Recent research into the pathogenesis of POCD has primarily focused on neuroinflammation, oxidative stress, changes in neural synaptic plasticity and neurotransmitter imbalances. Given the high-energy metabolism of neurons and their critical dependency on mitochondria, mitochondrial dysfunction directly affects neuronal function. Additionally, as the primary organelles generating reactive oxygen species, mitochondria are closely linked to the pathological processes of neuroinflammation. Surgery and anesthesia can induce mitochondrial dysfunction, increase mitochondrial oxidative stress, and disrupt mitochondrial quality-control mechanisms via various pathways, hence serving as key initiators of the POCD pathological process. We conducted a review on the role and potential mechanisms of mitochondria in postoperative cognitive dysfunction by consulting relevant literature from the PubMed and EMBASE databases spanning the past 25 years. Our findings indicate that surgery and anesthesia can inhibit mitochondrial respiration, thereby reducing ATP production, decreasing mitochondrial membrane potential, promoting mitochondrial fission, inducing mitochondrial calcium buffering abnormalities and iron accumulation, inhibiting mitophagy, and increasing mitochondrial oxidative stress. Mitochondrial dysfunction and damage can ultimately lead to impaired neuronal function, abnormal synaptic transmission, impaired synthesis and release of neurotransmitters, and even neuronal death, resulting in cognitive dysfunction. Targeted mitochondrial therapies have shown positive outcomes, holding promise as a novel treatment for POCD.

Mitochondrial dynamics and psychiatric disorders: The missing link

Elucidating the molecular mechanisms of psychopathology is crucial for optimized diagnosis and treatment. Accumulating data have underlined how mitochondrial bioenergetics affect major psychiatric disorders. However, how mitochondrial dynamics, a term addressing mitochondria quality control, including mitochondrial fission, fusion, biogenesis and mitophagy, is implicated in psychopathologies remains elusive. In this review, we summarize the existing literature on mitochondrial dynamics perturbations in psychiatric disorders/neuropsychiatric phenotypes. We include preclinical/clinical literature on mitochondrial dynamics recalibrations in anxiety, depression, post-traumatic stress disorder (PTSD), bipolar disorder and schizophrenia. We discuss alterations in mitochondrial network, morphology and shape, molecular markers of the mitochondrial dynamics machinery and mitochondrial DNA copy number (mtDNAcn) in animal models and human cohorts in brain and peripheral material. By looking for common altered mitochondrial dynamics patterns across diagnoses/phenotypes, we highlight mitophagy and biogenesis as regulators of anxiety and depression pathophysiology, respectively, as well as the fusion mediator dynamin-like 120 kDa protein (Opa1) as a molecular hub contributing to psychopathology. Finally, we comment on limitations and future directions in this novel neuropsychiatry field.

Mitochondrial Dynamics and mRNA Translation: A Local Synaptic Tale

Mitochondria are dynamic organelles that can adjust and respond to different stimuli within a cell. This plastic ability allows them to effectively coordinate several cellular functions in cells and becomes particularly relevant in highly complex cells such as neurons. An imbalance in mitochondrial dynamics can disrupt mitochondrial function, leading to abnormal cellular function and ultimately to a range of diseases, including neurodegenerative disorders. Regulation of mRNA transport and local translation inside neurons is crucial for maintaining the proteome of distal mitochondria, which is vital for energy production and synaptic function. A significant portion of the axonal transcriptome is dedicated to mRNAs for mitochondrial proteins, emphasizing the importance of local translation in sustaining mitochondrial function in areas far from the cell body. In neurons, local translation and the regulation of mRNAs encoding mitochondrial-shaping proteins could be essential for synaptic plasticity and neuronal health. The dynamics of these mRNAs, including their transport and local translation, may influence the morphology and function of mitochondria, thereby affecting the overall energy status and responsiveness of synapses. Comprehending the mitochondria-related mRNA regulation and local translation, as well as its influence on mitochondrial morphology near the synapses will help to better understand neuronal physiology and neurological diseases where mitochondrial dysfunction and impaired synaptic plasticity play a central role.

Molecular mechanisms of mitochondrial homeostasis regulation in neurons and possible therapeutic approaches for Alzheimer's disease

Alzheimer's disease (AD) is a neurological disease with memory loss and cognitive decline, which affects a large proportion of the aging population. Regrettably, there are no drug to reverse or cure AD and drug development for the primary theory of amyloid beta deposition has mostly failed. Therefore, there is an urgent need to investigate novel strategies for preventing AD. Recent studies demonstrate that imbalance of mitochondrial homeostasis is a driver in Aβ accumulation, which can lead to the occurrence and deterioration of cognitive impairment in AD patients. This suggests that regulating neuronal mitochondrial homeostasis may be a new strategy for AD. We summarize the importance of mitochondrial homeostasis in AD neuron and its regulatory mechanisms in this review. In addition, we summarize the results of studies indicating mitochondrial dysfunction in AD subjects, including impaired mitochondrial energy production, oxidative stress, imbalance of mitochondrial protein homeostasis, imbalance of fusion and fission, imbalance of neuronal mitochondrial biogenesis and autophagy, and altered mitochondrial motility, in hope of providing possible therapeutic approaches for AD.

Mitochondrial regulation of adult hippocampal neurogenesis: Insights into neurological function and neurodevelopmental disorders

Mitochondria are essential regulators of cellular energy metabolism and play a crucial role in the maintenance and function of neuronal cells. Studies in the last decade have highlighted the importance of mitochondrial dynamics and bioenergetics in adult neurogenesis, a process that significantly influences cognitive function and brain plasticity. In this review, we examine the mechanisms by which mitochondria regulate adult neurogenesis, focusing on the impact of mitochondrial function on the behavior of neural stem/progenitor cells and the maturation and plasticity of newborn neurons in the adult mouse hippocampus. In addition, we explore the link between mitochondrial dysfunction, adult hippocampal neurogenesis and genes associated with cognitive deficits in neurodevelopmental disorders. In particular, we provide insights into how alterations in the transcriptional regulator NR2F1 affect mitochondrial dynamics and may contribute to the pathophysiology of the emerging neurodevelopmental disorder Bosch-Boonstra-Schaaf optic atrophy syndrome (BBSOAS). Understanding how genes involved in embryonic and adult neurogenesis affect mitochondrial function in neurological diseases might open new directions for therapeutic interventions aimed at boosting mitochondrial function during postnatal life.

Myokines: A central point in managing redox homeostasis and quality of life

Redox homeostasis is a crucial phenomenon that is obligatory for maintaining the healthy status of cells. However, the loss of redox homeostasis may lead to numerous diseases that ultimately result in a compromised quality of life. Skeletal muscle is an endocrine organ that secretes hundreds of myokines. Myokines are peptides and cytokines produced and released by muscle fibers. Skeletal muscle secreted myokines act as a robust modulator for regulating cellular metabolism and redox homeostasis which play a prime role in managing and improving metabolic function in multiple organs. Further, the secretory myokines maintain redox homeostasis not only in muscles but also in other organs of the body via stabilizing oxidants and antioxidant levels. Myokines are also engaged in maintaining mitochondrial dynamics as mitochondria is a central point for the generation of reactive oxygen species (ROS). Ergo, myokines also act as a central player in communicating signals to other organs, including the pancreas, gut, liver, bone, adipose tissue, brain, and skin via their autocrine, paracrine, or endocrine effects. The present review provides a comprehensive overview of skeletal muscle-secreted myokines in managing redox homeostasis and quality of life. Additionally, probable strategies will be discussed that provide a solution for a better quality of life.

MicroRNA-455-3P as a peripheral biomarker and therapeutic target for mild cognitive impairment and Alzheimer's disease

MicroRNAs are small non-coding RNAs evolutionary conserved molecules. They regulate cellular processes, including RNA silencing, post-translational gene expression and neurodegeneration. MicroRNAs are involved with human diseases such as cancer, Alzheimer's disease (AD) and others. Interestingly, cerebrospinal fluids (CSF) and the blood of AD patients have altered expressions of many RNAs, which may serve as potential peripheral biomarkers. The intensive investigation from our lab revealed that microRNA-455-3 P (miR-455-3p) is a strong candidate as a potential biomarker and therapeutic target for AD. Several genes implicated in the pathogenesis of AD are directly targeted by miR-455-3p. Several years of our lab research revealed that miR-455-3p regulates important physiological processes associated with AD, such as the processing of the amyloid precursor protein (APP), TGF-β signaling, the regulation of oxidative stress, mitochondrial biogenesis, and synaptic damages. The expression of miR-455-3p in mild cognitive impaired subjects and AD patients pointed out its involvement in AD progression. Recently, our lab generated both transgenic and knockout mice for miR-455-3p. Interestingly miR-455-3p transgenic mice showed superior cognitive learning, improved memory and extended lifespan compared to age matched wild-type mice, whereas miR-455-3-p knockout mice showed cognitive decline and reduced lifespan. Information derived from mouse models further demonstrated the advantageous impact of miR-455-3p on dendritic growth, synaptogenesis, and mitochondrial biogenesis in preventing the onset and progression of AD. The identification of miR-455-3p as a biomarker was suggested by its presence in postmortem AD brains, B-lymphocytes, and fibroblasts. Our hypothesis that miR-455-3p could be a peripheral biomarker and therapeutic target for AD.

The interplay between BDNF and PGC-1 alpha in maintaining brain health: role of exercise

Throughout our evolutionary history, physical activity has played a significant role in shaping our physiology. Advances in exercise science have further reinforced this concept by highlighting how exercise can change gene expression and molecular signaling to achieve various beneficial outcomes. Several studies have shown that exercise can alter neuronal functions to prevent neurodegenerative conditions like Parkinson's and Alzheimer's diseases. However, individual genotypes, phenotypes, and varying exercise protocols hinder the prescription of exercise as standard therapy. Moreover, exercise-induced molecular signaling targets can be double-edged swords, making it difficult to use exercise as the primary candidate for beneficial effects. For example, activating PGC-1 alpha and BDNF through exercise could produce several benefits in maintaining brain health, such as plasticity, neuronal survival, memory formation, cognition, and synaptic transmission. However, higher expression of BDNF might play a negative role in bipolar disorder. Therefore, further understanding of a specific mechanistic approach is required. This review focuses on how exercise-induced activation of these molecules could support brain health and discusses the potential underlying mechanisms of the effect of exercise-induced PGC-1 alpha and BDNF on brain health.

Excitotoxicity, Oxytosis/Ferroptosis, and Neurodegeneration: Emerging Insights into Mitochondrial Mechanisms

Mitochondrial dysfunction plays a pivotal role in the development of age-related diseases, particularly neurodegenerative disorders. The etiology of mitochondrial dysfunction involves a multitude of factors that remain elusive. This review centers on elucidating the role(s) of excitotoxicity, oxytosis/ferroptosis and neurodegeneration within the context of mitochondrial bioenergetics, biogenesis, mitophagy and oxidative stress and explores their intricate interplay in the pathogenesis of neurodegenerative diseases. The effective coordination of mitochondrial turnover processes, notably mitophagy and biogenesis, is assumed to be critically important for cellular resilience and longevity. However, the age-associated decrease in mitophagy impedes the elimination of dysfunctional mitochondria, consequently impairing mitochondrial biogenesis. This deleterious cascade results in the accumulation of damaged mitochondria and deterioration of cellular functions. Both excitotoxicity and oxytosis/ferroptosis have been demonstrated to contribute significantly to the pathophysiology of neurodegenerative diseases, including Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's Disease (HD), Amyotrophic Lateral Sclerosis (ALS) and Multiple Sclerosis (MS). Excitotoxicity, characterized by excessive glutamate signaling, initiates a cascade of events involving calcium dysregulation, energy depletion, and oxidative stress and is intricately linked to mitochondrial dysfunction. Furthermore, emerging concepts surrounding oxytosis/ferroptosis underscore the importance of iron-dependent lipid peroxidation and mitochondrial engagement in the pathogenesis of neurodegeneration. This review not only discusses the individual contributions of excitotoxicity and ferroptosis but also emphasizes their convergence with mitochondrial dysfunction, a key driver of neurodegenerative diseases. Understanding the intricate crosstalk between excitotoxicity, oxytosis/ferroptosis, and mitochondrial dysfunction holds potential to pave the way for mitochondrion-targeted therapeutic strategies. Such strategies, with a focus on bioenergetics, biogenesis, mitophagy, and oxidative stress, emerge as promising avenues for therapeutic intervention.

PGC-1α agonism induces fetal hemoglobin and exerts antisickling effects in sickle cell disease

Sickle cell disease is a growing health burden afflicting millions around the world. Clinical observation and laboratory studies have shown that the severity of sickle cell disease is ameliorated in individuals who have elevated levels of fetal hemoglobin. Additional pharmacologic agents to induce sufficient fetal hemoglobin to diminish clinical severity is an unmet medical need. We recently found that up-regulation of peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) can induce fetal hemoglobin synthesis in human primary erythroblasts. Here, we report that a small molecule, SR-18292, increases PGC-1α leading to enhanced fetal hemoglobin expression in human erythroid cells, β-globin yeast artificial chromosome mice, and sickle cell disease mice. In SR-18292-treated sickle mice, sickled red blood cells are significantly reduced, and disease complications are alleviated. SR-18292, or agents in its class, could be a promising additional therapeutic for sickle cell disease.

Effects of a Muscle Relaxation Technique on Catatonia Symptoms Associated With Schizophrenia: A Case Report

Catatonia is characterized by the loss of voluntary control over the workings of the mind and body. It disrupts daily life by manifesting as idle posture, heightened muscle tone, and repetitive purposeless movements. However, specific physiotherapy methods addressing these symptoms are yet to be established. This case report describes a 63-year-old man hospitalized for schizophrenia who was then diagnosed with stuporous catatonia based on the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR) criteria, characterized by catalepsy, mutism, and difficulty performing daily activities. This case report aimed to evaluate the effectiveness of a specific muscle relaxation technique, squeeze-hold (SH), in treating catatonia associated with schizophrenia and its impact on daily activities. The patient exhibited catalepsy, mutism, and difficulty in performing daily activities. The SH technique employed temporarily obstructs muscle blood flow to induce ischemia, resulting in the relaxation of vascular smooth muscle due to CO2 retention. Furthermore, shear stress upon reperfusion stimulates nitric oxide production in the vascular endothelium, enhancing blood flow. Following weekly SH on the bilateral thighs, the muscle tone in the lower extremities was alleviated within two weeks, and the patient no longer required a wheelchair by the eighth week. In addition, responsiveness to verbal commands improved. As muscle tone in the lower limbs improved, the patient regained ambulation, and his improved responsiveness facilitated independent eating during activities of daily living (ADLs), potentially enhancing motivation and spontaneity. These findings suggest that muscle tone relaxation due to enhanced blood flow and increased CO2 concentration from blood flow restriction may have promoted β-endorphin secretion, thereby improving symptoms via brain-derived neurotrophic factor expression through PGC-1α activation. In conclusion, the SH muscle relaxation technique effectively alleviated catatonic symptoms, and improved muscle tone and daily functioning in patients with schizophrenia-associated catatonia. These findings suggest that this physiotherapy approach may be a valuable addition to catatonia treatment, potentially contributing to physical and psychiatric rehabilitation. This case report illustrates the efficacy of a muscle-tone-focused treatment approach in physical therapy for catatonia and posits its contribution to the reacquisition of psychiatric function and ADLs.

Aging-associated decrease of PGC-1α promotes pain chronification

Aging is generally associated with declining somatosensory function, which seems at odds with the high prevalence of chronic pain in older people. This discrepancy is partly related to the high prevalence of degenerative diseases such as osteoarthritis in older people. However, whether aging alters pain processing in the primary somatosensory cortex (S1), and if so, whether it promotes pain chronification is largely unknown. Herein, we report that older mice displayed prolonged nociceptive behavior following nerve injury when compared with mature adult mice. The expression of peroxisome proliferator-activated receptor-gamma coactivator-1α (PGC-1α) in S1 was decreased in older mice, whereas PGC-1α haploinsufficiency promoted prolonged nociceptive behavior after nerve injury. Both aging and PGC-1α haploinsufficiency led to abnormal S1 neural dynamics, revealed by intravital two-photon calcium imaging. Manipulating S1 neural dynamics affected nociceptive behavior after nerve injury: chemogenetic inhibition of S1 interneurons aggravated nociceptive behavior in naive mice; chemogenetic activation of S1 interneurons alleviated nociceptive behavior in older mice. More interestingly, adeno-associated virus-mediated expression of PGC-1α in S1 interneurons ameliorated aging-associated chronification of nociceptive behavior as well as aging-related S1 neural dynamic changes. Taken together, our results showed that aging-associated decrease of PGC-1α promotes pain chronification, which might be harnessed to alleviate the burden of chronic pain in older individuals.

The relevance of BDNF for neuroprotection and neuroplasticity in multiple sclerosis

Background

Neuroplasticity as a mechanism to overcome central nervous system injury resulting from different neurological diseases has gained increasing attention in recent years. However, deficiency of these repair mechanisms leads to the accumulation of neuronal damage and therefore long-term disability. To date, the mechanisms by which remyelination occurs and why the extent of remyelination differs interindividually between multiple sclerosis patients regardless of the disease course are unclear. A member of the neurotrophins family, the brain-derived neurotrophic factor (BDNF) has received particular attention in this context as it is thought to play a central role in remyelination and thus neuroplasticity, neuroprotection, and memory.

Objective

To analyse the current literature regarding BDNF in different areas of multiple sclerosis and to provide an overview of the current state of knowledge in this field.

Conclusion

To date, studies assessing the role of BDNF in patients with multiple sclerosis remain inconclusive. However, there is emerging evidence for a beneficial effect of BDNF in multiple sclerosis, as studies reporting positive effects on clinical as well as MRI characteristics outweighed studies assuming detrimental effects of BDNF. Furthermore, studies regarding the Val66Met polymorphism have not conclusively determined whether this is a protective or harmful factor in multiple sclerosis, but again most studies hypothesized a protective effect through modulation of BDNF secretion and anti-inflammatory effects with different effects in healthy controls and patients with multiple sclerosis, possibly due to the pro-inflammatory milieu in patients with multiple sclerosis. Further studies with larger cohorts and longitudinal follow-ups are needed to improve our understanding of the effects of BDNF in the central nervous system, especially in the context of multiple sclerosis.

Electron Microscopic Mapping of Mitochondrial Morphology in the Cochlear Nerve Fibers

To enable nervous system function, neurons are powered in a use-dependent manner by mitochondria undergoing morphological-functional adaptation. In a well-studied model system-the mammalian cochlea, auditory nerve fibers (ANFs) display distinct electrophysiological properties, which is essential for collectively sampling acoustic information of a large dynamic range. How exactly the associated mitochondrial networks are deployed in functionally differentiated ANFs remains scarcely interrogated. Here, we leverage volume electron microscopy and machine-learning-assisted image analysis to phenotype mitochondrial morphology and distribution along ANFs of full-length in the mouse cochlea inner spiral bundle. This reveals greater variance in mitochondrial size with increased ANF habenula to terminal path length. Particularly, we analyzed the ANF terminal-residing mitochondria, which are critical for local calcium uptake during sustained afferent activities. Our results suggest that terminal-specific enrichment of mitochondria, in addition to terminal size and overall mitochondrial abundance of the ANF, correlates with heterogenous mitochondrial contents of the terminal.

Integrating analysis of mRNA expression profiles indicates Sgk1 as a key mediator in muscle-brain crosstalk during resistance exercise

Abundant evidence has shown the protective effect of aerobic exercise on central neuronal system, however, research about resistance exercise remains limited. To evaluate the effect and potential molecular mechanisms of resistance exercise in improving cognition and mental health, three-month-old male C57BL/6J mice underwent resistance training for five weeks. Body parameters, cognitive performance and synaptic plasticity were then assessed. In both groups, total RNA from the frontal cortex, hippocampus and gastrocnemius was isolated and sequenced, GO term and KEGG analysis were performed to identify molecular mechanisms. The results from RNA sequencing were then verified by RT-PCR. Our data found that mice in training group showed reduced anxiety-like behavior and better spatial memory. Accordingly, resistance exercise specifically increased the number of thin spines without affecting the number of other kind of spines. mRNA sequence analysis showed that resistance exercise induced differential expression of hundreds of genes in the above three tissues. KEGG analysis indicated the FoxO signaling pathway the most significant changed pathway throughout the brain and muscle. GO terms analysis showed that Sgk1 was enriched in the three key cognition related BP, including long-term memory, learning or memory and memory, and the expression level of Sgk1 was positive related with cognitive performance in the water maze. In conclusion, resistance exercise improved the mental health, cognition and synaptic plasticity of mice. Integrating analysis of mRNA expression profiles in frontal cortex, hippocampus and muscle reveals Sgk1 as the key mediator in brain-muscle crosstalk.

Activation of GPER1 by G1 prevents PTSD-like behaviors in mice: Illustrating the mechanisms from BDNF/TrkB to mitochondria and synaptic connection

BACKGROUND

G1 is a specific agonist of G protein-coupled estrogen receptor 1 (GPER1), which binds and activates GPER1 to exert various neurological functions. However, the preventive effect of G1 on post-traumatic stress disorder (PTSD) and its mechanisms are unclear.

OBJECTIVE

To evaluate the protective effect of G1 against synaptic and mitochondrial impairments and to investigate the mechanism of G1 to improve PTSD from brain-derived neurotrophic factor (BDNF)/tyrosine kinase receptor B (TrkB) signaling.

METHODS

This study initially detected GPER1 expression in the hippocampus of single prolonged stress (SPS) mice, utilizing both Western blot and immunofluorescence staining. Subsequently, the effects of G1 on PTSD-like behaviors, synaptic, and mitochondrial functions in SPS mice were investigated. Additionally, the involvement of BDNF/TrkB signaling involved in the protection was further confirmed using GPER1 antagonist and TrkB inhibitor, respectively.

RESULTS

The expression of GPER1 was reduced in the hippocampus of SPS mice, and G1 treatment given for 14 consecutive days significantly improved PTSD-like behaviors in SPS mice compared with model group. Electrophysiological local field potential (LFP) results showed that G1 administration for 14 consecutive days could reverse the abnormal changes in the gamma oscillation in the CA1 region of SPS mice. Meanwhile, G1 administration for 14 consecutive days could significantly improve the abnormal expression of synaptic proteins, increase the expression of mitochondria-related proteins, increase the number of synapses in the hippocampus, and ameliorate the damage of hippocampal mitochondrial structure in SPS mice. In addition, G15 (GPER1 inhibitor) and ANA-12 (TrkB inhibitor) blocked the ameliorative effects of G1 on PTSD-like behaviors and aberrant expression of hippocampal synaptic and mitochondrial proteins in SPS mice and inhibited the reparative effects of G1 on structural damage to hippocampal mitochondria, respectively.

CONCLUSION

G1 improved PTSD-like behaviors in SPS mice, possibly by increasing hippocampal GPER1 expression and promoting BDNF/TrkB signaling to repair synaptic and mitochondrial functional impairments. This study would provide critical mechanism for the prevention and treatment of PTSD.

Mitochondrial mechanisms in Cerebral Ischemia-Reperfusion Injury: Unravelling the intricacies

Cerebral ischemic stroke is a major contributor to physical impairments and premature death worldwide. The available reperfusion therapies for stroke in the form of mechanical thrombectomy and intravenous thrombolysis increase the risk of cerebral ischemia-reperfusion (I-R) injury due to sudden restoration of blood supply to the ischemic region. The injury is manifested by hemorrhagic transformation, worsening of neurological impairments, cerebral edema, and progression to infarction in surviving patients. A complex network of multiple pathological processes has been known to be involved in the pathogenesis of I-R injury. Primarily, 3 major contributors namely oxidative stress, neuroinflammation, and mitochondrial failure have been well studied in I-R injury. A transcription factor, Nrf2 (Nuclear factor erythroid 2-related factor 2) plays a crucial defensive role in resisting the deleterious effects of I-R injury and potentiating the cellular protective mechanisms. In this review, we delve into the critical function of mitochondria and Nrf2 in the context of cerebral I-R injury. We summarized how oxidative stress, neuroinflammation, and mitochondrial anomaly contribute to the pathophysiology of I-R injury and further elaborated the role of Nrf2 as a pivotal guardian of cellular integrity. The review further highlighted Nrf2 as a putative therapeutic target for mitochondrial dysfunction in cerebral I-R injury management.

PGC-1α in the hippocampus mediates depressive-like and stress-coping behaviours and regulates excitatory synapses in the dentate gyrus in mice

Decreased hippocampal synaptic plasticity is an important pathological change in stress-related mood disorders, including major depressive disorder. However, the underlying mechanism is unclear. PGC-1α, a transcriptional coactivator, is a key factor in synaptic plasticity. We investigated the relationships between changes in hippocampal PGC-1α expression and depressive-like and stress-coping behaviours, and whether they are related to hippocampal synapses. Adeno-associated virus was used to alter hippocampal PGC-1α expression in male C57BL/6 mice. The sucrose preference test and forced swimming test were used to assess their depressive-like and stress-coping behaviours, respectively. Immunohistochemistry and stereology were used to calculate the total number of excitatory synapses in each hippocampal subregion (the cornu ammonis (CA) 1, CA3, and dentate gyrus). Immunofluorescence was used to visualize the changes in dendritic structure. Western blotting was used to detect the expression of hippocampal PGC-1α and mitochondrial-associated proteins, such as UCP2, NRF1 and mtTFAs. Our results showed that mice with downregulated PGC-1α expression in the hippocampus exhibited depressive-like and passive stress-coping behaviours, while mice with upregulated PGC-1α in the hippocampus exhibited increased stress-coping behaviours. Moreover, the downregulation of hippocampal PGC-1α expression resulted in a decrease in the number of excitatory synapses in the DG and in the protein expression of UCP2 in the hippocampus. Alternatively, upregulation of hippocampal PGC-1α yielded the opposite results. This suggests that hippocampal PGC-1α is involved in regulating depressive-like and stress-coping behaviours and modulating the number of excitatory synapses in the DG. This provides new insight for the development of antidepressants.

Exploring exercise-driven exerkines: unraveling the regulation of metabolism and inflammation

Exercise has many beneficial effects that provide health and metabolic benefits. Signaling molecules are released from organs and tissues in response to exercise stimuli and are widely termed exerkines, which exert influence on a multitude of intricate multi-tissue processes, such as muscle, adipose tissue, pancreas, liver, cardiovascular tissue, kidney, and bone. For the metabolic effect, exerkines regulate the metabolic homeostasis of organisms by increasing glucose uptake and improving fat synthesis. For the anti-inflammatory effect, exerkines positively influence various chronic inflammation-related diseases, such as type 2 diabetes and atherosclerosis. This review highlights the prospective contribution of exerkines in regulating metabolism, augmenting the anti-inflammatory effects, and providing additional advantages associated with exercise. Moreover, a comprehensive overview and analysis of recent advancements are provided in this review, in addition to predicting future applications used as a potential biomarker or therapeutic target to benefit patients with chronic diseases.

Neuroprotective Effects of Intermittent Fasting in the Aging Brain

BACKGROUND

A major risk factor for neurodegenerative disorders is old age. Nutritional interventions that delay aging, such as calorie restriction (CR) and intermittent fasting (IF), as well as pharmaceuticals that affect the pathways linking nutrition and aging processes, have been developed in recent decades and have been shown to alleviate the effects of aging on the brain.

SUMMARY

CR is accomplished by alternating periods of ad libitum feeding and fasting. In animal models, IF has been shown to increase lifespan and slow the progression and severity of age-related pathologies such as cardiovascular and neurodegenerative diseases and cancer. According to recent research, dietary changes can help older people with dementia retain brain function. However, the mechanisms underlying the neuroprotective effect of IF on the aging brain and related questions in this area of study (i.e., the potential of IF to treat neurodegenerative disorders) remain to be examined.

KEY MESSAGES

This review addresses the hypothesis that IF may have translational potential in protecting the aged brain while summarizing the research supporting the putative neuroprotective mechanisms of IF in animal models. Additionally, given the emerging understanding of the connection between aging and dementia, our investigations may offer a fresh perspective on the use of dietary interventions for enhancing brain function and preventing dementia in elderly individuals. Finally, the absence of guidelines regarding the application of IF in patients hampers its broad utilization in clinical practice, and further studies are needed to improve our knowledge of the long-term effects of IF on dementia before it can be widely prescribed. In conclusion, IF may be an ancillary intervention for preserving memory and cognition in elderly individuals.

Focusing on mitochondria in the brain: from biology to therapeutics

Mitochondria have multiple functions such as supplying energy, regulating the redox status, and producing proteins encoded by an independent genome. They are closely related to the physiology and pathology of many organs and tissues, among which the brain is particularly prominent. The brain demands 20% of the resting metabolic rate and holds highly active mitochondrial activities. Considerable research shows that mitochondria are closely related to brain function, while mitochondrial defects induce or exacerbate pathology in the brain. In this review, we provide comprehensive research advances of mitochondrial biology involved in brain functions, as well as the mitochondria-dependent cellular events in brain physiology and pathology. Furthermore, various perspectives are explored to better identify the mitochondrial roles in neurological diseases and the neurophenotypes of mitochondrial diseases. Finally, mitochondrial therapies are discussed. Mitochondrial-targeting therapeutics are showing great potentials in the treatment of brain diseases.

Exploring the effect of Anshen Dingzhi prescription on hippocampal mitochondrial signals in single prolonged stress mouse model

HEADINGS ETHNOPHARMACOLOGICAL RELEVANCE

Anshen Dingzhi prescription (ADP), which was first published in the masterpiece of traditional Chinese Medicine in the Qing Dynasty, "Yi Xue Xin Wu" (1732 CE), is documented to interrupt panic-related disorders. However, the mechanism of its action is still not clear.

AIM OF THE STUDY

This study aims to investigate the effects of ADP on post-traumatic stress disorder (PTSD)-like behaviors and explore the mechanism from perspective of sirtuin1 (SIRT1)-peroxisome proliferator-activated receptor gamma co-activator 1 alpha (PGC-1α)-dependent mitochondrial function.

MATERIALS AND METHODS

The changes of SIRT1-PGC-1α signal and mitochondrial function were evaluated in the hippocampus of mice receiving single prolonged stress (SPS). Later, the roles of this signaling pathway played in fear memory generalization and anxiety-like behavior in SPS mice was investigated using two agonists of this signaling pathway. On this basis, the effects of ADP (36.8 mg/kg) with definite therapeutic effects, on mitochondrial function were investigated and further confirmed by a SIRT1 inhibitor. Finally, the possible components of ADP targeting PGC-1α were monitored through bioinformatics.

RESULTS

Compared with control mice, SIRT1-PGC-1α signal in the hippocampus was impaired in SPS mice, accompanied with dysfunction of mitochondria and abnormal expression of synaptic proteins. The agonists of SIRT1-PGC-1α signal, ZLN005, as well as resveratrol improved the behavioral changes of mice caused by SPS, reversed the decline of proteins in SIRT1-PGC-1α signal, mitochondrial dysfunction, and the abnormal expression of synaptic proteins. The fingerprint was established for the quality control of ADP. At a dose of 36.8 mg/kg, ADP could prevent fear memory generalization and anxiety-like behavior in SPS mice. Mechanically, ADP promoted SIRT1-PGC-1α signal and repaired mitochondrial function. Importantly, SIRT1 inhibitor, selisistat eliminated the ameliorative effects of ADP on behavioral and mitochondrial function. Through molecular docking simulation, the brain-entering components of ADP, including malkangunin, Rg5, fumarine, frutinone A, celabenzine, and inermin had high binding energy with PGC-1α.

CONCLUSION

Dysfunction of SIRT1-PGC-1α-dependent mitochondrial function is attributed to SPS-triggered fear generalization and anxiety-like behavior, and ADP could improve PTSD-like behaviors likely through activating this signaling pathway.

Tetramethylpyrazine Nitrone Promotes the Clearance of Alpha-Synuclein via Nrf2-Mediated Ubiquitin-Proteasome System Activation

Aggregation of α-synuclein (α-syn) and α-syn cytotoxicity are hallmarks of sporadic and familial Parkinson's disease (PD). Nuclear factor (erythroid-derived 2)-like 2 (Nrf2)-dependent enhancement of the expression of the 20S proteasome core particles (20S CPs) and regulatory particles (RPs) increases proteasome activity, which can promote α-syn clearance in PD. Activation of peroxisome proliferator-activated receptor γ co-activator 1α (PGC-1α) may reduce oxidative stress by strongly inducing Nrf2 gene expression. In the present study, tetramethylpyrazine nitrone (TBN), a potent-free radical scavenger, promoted α-syn clearance by the ubiquitin-proteasome system (UPS) in cell models overexpressing the human A53T mutant α-syn. In the α-syn transgenic mice model, TBN improved motor impairment, decreased the products of oxidative damage, and down-regulated the α-syn level in the serum. TBN consistently up-regulated PGC-1α and Nrf2 expression in tested models of PD. Additionally, TBN similarly enhanced the proteasome 20S subunit beta 8 (Psmb8) expression, which is linked to chymotrypsin-like proteasome activity. Furthermore, TBN increased the mRNA levels of both the 11S RPs subunits Pa28αβ and a proteasome chaperone, known as the proteasome maturation protein (Pomp). Interestingly, specific siRNA targeting of Nrf2 blocked TBN's effects on Psmb8, Pa28αβ, Pomp expression, and α-syn clearance. In conclusion, TBN promotes the clearance of α-syn via Nrf2-mediated UPS activation, and it may serve as a potentially disease-modifying therapeutic agent for PD.

Dietary fasting and time-restricted eating in Huntington's disease: therapeutic potential and underlying mechanisms

Huntington's disease (HD) is a devastating neurodegenerative disorder caused by aggregation of the mutant huntingtin (mHTT) protein, resulting from a CAG repeat expansion in the huntingtin gene HTT. HD is characterized by a variety of debilitating symptoms including involuntary movements, cognitive impairment, and psychiatric disturbances. Despite considerable efforts, effective disease-modifying treatments for HD remain elusive, necessitating exploration of novel therapeutic approaches, including lifestyle modifications that could delay symptom onset and disease progression. Recent studies suggest that time-restricted eating (TRE), a form of intermittent fasting involving daily caloric intake within a limited time window, may hold promise in the treatment of neurodegenerative diseases, including HD. TRE has been shown to improve mitochondrial function, upregulate autophagy, reduce oxidative stress, regulate the sleep-wake cycle, and enhance cognitive function. In this review, we explore the potential therapeutic role of TRE in HD, focusing on its underlying physiological mechanisms. We discuss how TRE might enhance the clearance of mHTT, recover striatal brain-derived neurotrophic factor levels, improve mitochondrial function and stress-response pathways, and synchronize circadian rhythm activity. Understanding these mechanisms is critical for the development of targeted lifestyle interventions to mitigate HD pathology and improve patient outcomes. While the potential benefits of TRE in HD animal models are encouraging, future comprehensive clinical trials will be necessary to evaluate its safety, feasibility, and efficacy in persons with HD.

Exercise-induced BDNF promotes PPARδ-dependent reprogramming of lipid metabolism in skeletal muscle during exercise recovery

Post-exercise recovery is essential to resolve metabolic perturbations and promote long-term cellular remodeling in response to exercise. Here, we report that muscle-generated brain-derived neurotrophic factor (BDNF) elicits post-exercise recovery and metabolic reprogramming in skeletal muscle. BDNF increased the post-exercise expression of the gene encoding PPARδ (peroxisome proliferator-activated receptor δ), a transcription factor that is a master regulator of lipid metabolism. After exercise, mice with muscle-specific Bdnf knockout (MBKO) exhibited impairments in PPARδ-regulated metabolic gene expression, decreased intramuscular lipid content, reduced β-oxidation, and dysregulated mitochondrial dynamics. Moreover, MBKO mice required a longer period to recover from a bout of exercise and did not show increases in exercise-induced endurance capacity. Feeding naïve mice with the bioavailable BDNF mimetic 7,8-dihydroxyflavone resulted in effects that mimicked exercise-induced adaptations, including improved exercise capacity. Together, our findings reveal that BDNF is an essential myokine for exercise-induced metabolic recovery and remodeling in skeletal muscle.

Peroxisome proliferator-activated receptor gamma coactivator-1 (PGC-1) family in physiological and pathophysiological process and diseases

Peroxisome proliferator-activated receptor gamma coactivator-1 (PGC-1) family (PGC-1s), consisting of three members encompassing PGC-1α, PGC-1β, and PGC-1-related coactivator (PRC), was discovered more than a quarter-century ago. PGC-1s are essential coordinators of many vital cellular events, including mitochondrial functions, oxidative stress, endoplasmic reticulum homeostasis, and inflammation. Accumulating evidence has shown that PGC-1s are implicated in many diseases, such as cancers, cardiac diseases and cardiovascular diseases, neurological disorders, kidney diseases, motor system diseases, and metabolic disorders. Examining the upstream modulators and co-activated partners of PGC-1s and identifying critical biological events modulated by downstream effectors of PGC-1s contribute to the presentation of the elaborate network of PGC-1s. Furthermore, discussing the correlation between PGC-1s and diseases as well as summarizing the therapy targeting PGC-1s helps make individualized and precise intervention methods. In this review, we summarize basic knowledge regarding the PGC-1s family as well as the molecular regulatory network, discuss the physio-pathological roles of PGC-1s in human diseases, review the application of PGC-1s, including the diagnostic and prognostic value of PGC-1s and several therapies in pre-clinical studies, and suggest several directions for future investigations. This review presents the immense potential of targeting PGC-1s in the treatment of diseases and hopefully facilitates the promotion of PGC-1s as new therapeutic targets.

Reversal of neuronal tau pathology, metabolic dysfunction, and electrophysiological defects via adiponectin pathway-dependent AMPK activation

Changes in brain mitochondrial metabolism are coincident with functional decline; however, direct links between the two have not been established. Here, we show that mitochondrial targeting via the adiponectin receptor activator AdipoRon (AR) clears neurofibrillary tangles (NFTs) and rescues neuronal tauopathy-associated defects. AR reduced levels of phospho-tau and lowered NFT burden by a mechanism involving the energy-sensing kinase AMPK and the growth-sensing kinase GSK3b. The transcriptional response to AR included broad metabolic and functional pathways. Induction of lysosomal pathways involved activation of LC3 and p62, and restoration of neuronal outgrowth required the stress-responsive kinase JNK. Negative consequences of NFTs on mitochondrial activity, ATP production, and lipid stores were corrected. Defects in electrophysiological measures (e.g., resting potential, resistance, spiking profiles) were also corrected. These findings reveal a network linking mitochondrial function, cellular maintenance processes, and electrical aspects of neuronal function that can be targeted via adiponectin receptor activation.

The hormesis principle of neuroplasticity and neuroprotection

Animals live in habitats fraught with a range of environmental challenges to their bodies and brains. Accordingly, cells and organ systems have evolved stress-responsive signaling pathways that enable them to not only withstand environmental challenges but also to prepare for future challenges and function more efficiently. These phylogenetically conserved processes are the foundation of the hormesis principle, in which single or repeated exposures to low levels of environmental challenges improve cellular and organismal fitness and raise the probability of survival. Hormetic principles have been most intensively studied in physical exercise but apply to numerous other challenges known to improve human health (e.g., intermittent fasting, cognitive stimulation, and dietary phytochemicals). Here we review the physiological mechanisms underlying hormesis-based neuroplasticity and neuroprotection. Approaching natural resilience from the lens of hormesis may reveal novel methods for optimizing brain function and lowering the burden of neurological disorders.

A mitochondrial nexus in major depressive disorder: Integration with the psycho-immune-neuroendocrine network

Nervous system processes, including cognition and affective state, fundamentally rely on mitochondria. Impaired mitochondrial function is evident in major depressive disorder (MDD), reflecting cumulative detrimental influences of both extrinsic and intrinsic stressors, genetic predisposition, and mutation. Glucocorticoid 'stress' pathways converge on mitochondria; oxidative and nitrosative stresses in MDD are largely mitochondrial in origin; both initiate cascades promoting mitochondrial DNA (mtDNA) damage with disruptions to mitochondrial biogenesis and tryptophan catabolism. Mitochondrial dysfunction facilitates proinflammatory dysbiosis while directly triggering immuno-inflammatory activation via released mtDNA, mitochondrial lipids and mitochondria associated membranes (MAMs), further disrupting mitochondrial function and mitochondrial quality control, promoting the accumulation of abnormal mitochondria (confirmed in autopsy studies). Established and putative mechanisms highlight a mitochondrial nexus within the psycho-immune neuroendocrine (PINE) network implicated in MDD. Whether lowering neuronal resilience and thresholds for disease, or linking mechanistic nodes within the MDD pathogenic network, impaired mitochondrial function emerges as an important risk, a functional biomarker, providing a therapeutic target in MDD. Several treatment modalities have been demonstrated to reset mitochondrial function, which could benefit those with MDD.

Common and divergent molecular mechanisms of fasting and ketogenic diets

Intermittent short-term fasting (ISTF) and ketogenic diets (KDs) exert overlapping but not identical effects on cell metabolism, function, and resilience. Whereas health benefits of KD are largely mediated by the ketone bodies (KBs), ISTF engages additional adaptive physiological responses. KDs act mainly through inhibition of histone deacetylases (HDACs), reduction of oxidative stress, improvement of mitochondria efficiency, and control of inflammation. Mechanisms of action of ISTF include stimulation of autophagy, increased insulin and leptin sensitivity, activation of AMP-activated protein kinase (AMPK), inhibition of the mechanistic target of rapamycin (mTOR) pathway, bolstering mitochondrial resilience, and suppression of oxidative stress and inflammation. Frequent switching between ketogenic and nonketogenic states may optimize health by increasing stress resistance, while also enhancing cell plasticity and functionality.

Mitophagy in intracerebral hemorrhage: a new target for therapeutic intervention

Intracerebral hemorrhage is a life-threatening condition with a high fatality rate and severe sequelae. However, there is currently no treatment available for intracerebral hemorrhage, unlike for other stroke subtypes. Recent studies have indicated that mitochondrial dysfunction and mitophagy likely relate to the pathophysiology of intracerebral hemorrhage. Mitophagy, or selective autophagy of mitochondria, is an essential pathway to preserve mitochondrial homeostasis by clearing up damaged mitochondria. Mitophagy markedly contributes to the reduction of secondary brain injury caused by mitochondrial dysfunction after intracerebral hemorrhage. This review provides an overview of the mitochondrial dysfunction that occurs after intracerebral hemorrhage and the underlying mechanisms regarding how mitophagy regulates it, and discusses the new direction of therapeutic strategies targeting mitophagy for intracerebral hemorrhage, aiming to determine the close connection between mitophagy and intracerebral hemorrhage and identify new therapies to modulate mitophagy after intracerebral hemorrhage. In conclusion, although only a small number of drugs modulating mitophagy in intracerebral hemorrhage have been found thus far, most of which are in the preclinical stage and require further investigation, mitophagy is still a very valid and promising therapeutic target for intracerebral hemorrhage in the long run.

Humanin ameliorates TBI-related cognitive impairment by attenuating mitochondrial dysfunction and inflammation

Traumatic brain injury (TBI) often results in a reduction of the capacity of cells to sustain energy demands, thus, compromising neuronal function and plasticity. Here we show that the mitochondrial activator humanin (HN) counteracts a TBI-related reduction in mitochondrial bioenergetics, including oxygen consumption rate. HN normalized the disruptive action of TBI on memory function, and restored levels of synaptic proteins (synapsin 1 and p-CREB). HN also counteracted TBI-related elevations of pro-inflammatory cytokines in plasma (TNF-α, INF-y, IL 17, IL 5, MCP 5, GCSF, RANNETS, sTNFRI) as well as in the hippocampus (gp-130 and p-STAT3). Gp-130 is an integral part of cytokine receptor impinging on STAT3 (Tyr-705) signaling. Furthermore, HN reduced astrocyte proliferation in TBI. The overall evidence suggests that HN plays an integral role in normalizing fundamental aspects of TBI pathology which are central to energy balance, brain function, and plasticity.