PGC-1α sparks the fire of neuroprotection against neurodegenerative disorders

A promising drug repurposing approach for Alzheimer's treatment: Givinostat improves cognitive behavior and pathological features in APP/PS1 mice

Alzheimer's disease (AD) is the most common neurodegenerative disease, characterized by memory loss, speech and motor defects, personality changes, and psychological disorders. The exact cause of AD remains unclear. Current treatments focus on maintaining neurotransmitter levels or targeting β-amyloid (Aβ) protein, but these only alleviate symptoms and do not reverse the disease. Developing new drugs is time-consuming, costly, and has a high failure rate. Utilizing multi-omics for drug repositioning has emerged as a new strategy. Based on transcriptomic perturbation data of over 40,000 drugs in human cells from the LINCS-L1000 database, our study employed the Jaccard index and hypergeometric distribution test for reverse transcriptional feature matching analysis, identifying Givinostat as a potential treatment for AD. Our research found that Givinostat improved cognitive behavior and brain pathology in models and enhanced hippocampal synaptic plasticity. Transcriptome sequencing revealed increased expression of mitochondrial respiratory chain complex proteins in the brains of APP/PS1 mice after Givinostat treatment. Functionally, Givinostat restored mitochondrial membrane potential, reduced reactive oxygen species, and increased ATP content in Aβ-induced HT22 cells. Additionally, it improved mitochondrial morphology and quantity in the hippocampus of APP/PS1 mice and enhanced brain glucose metabolic activity. These effects are linked to Givinostat promoting mitochondrial biogenesis and improving mitochondrial function. In summary, Givinostat offers a promising new strategy for AD treatment by targeting mitochondrial dysfunction.

Potential effect of acupuncture on mitochondrial biogenesis, energy metabolism and oxidation stress in MCAO rat via PGC-1α/NRF1/TFAM pathway

PURPOSE

To explore possible mechanism(s) underlying beneficial effects of acupuncture treatment for alleviating focal cerebral infarction-induced neuronal injury, mitochondrial biogenesis, energy metabolism, oxidative stress and dendrite regeneration were evaluated in rats with experimentally induced cerebral ischemia and dendron reperfusion.

MATERIALS AND METHODS

Rats were randomly assigned to three groups (sham-operated, operated group without acupuncture, operated group with acupuncture). RT-PCR and Western blotting were used to assess variations of hippocampal cell mitochondrial DNA (mtDNA) copy number and mRNA and protein expression levels associated with key mitochondrial biogenesis proteins, namely peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α), nuclear respiration factor 1 (NRF-1) and mitochondrial transcription factor A (TFAM). To evaluate mitochondrial oxidative phosphorylation and respiratory function in ischemic tissues, oxidative phosphorylation protein complex expression levels were assessed via Western blot analysis, mitochondrial membrane potential (MMP) was assessed via confocal microscopy and flow cytometry and adenosine triphosphate (ATP) concentration was assessed using an enzymatic fluorescence-based assay. Immunofluorescence staining was used to evaluate the expression of the neuronal dendron formation marker-Microtubule Associated Protein 2 (MAP2). Additionally, oxidative stress levels were assessed based on superoxide dismutase (SOD) activity, lipid oxidation levels (malondialdehyde, MDA) and glutathione (GSH) levels. Meanwhile, 2,3,5-triphenyltetrazolium chloride (TTC) staining, Nissl staining, transmission electron microscopy observation and neuro behavioral status were used to determine cerebral infarction volume and extent of brain injury.

RESULTS

Acupuncture treatment effectively stimulated mRNA-level and protein-level expression associated with PGC-1α, NRF-1 and TFAM and increased levels of electron transport chain complexes I, IV and V, thereby increasing the ATP concentration, maintaining mitochondrial membrane potential, and promoting dendron regeneration levels. Meanwhile, in hippocampal neurons SOD activity and the glutathione/glutathione disulfide (GSH/GSSG) ratio increased and MDA level decreased.

CONCLUSION

Acupuncture treatment after ischemic injury promoted mitochondrial biogenesis, as reflected by beneficially increased mitochondrial oxidative phosphorylation complex protein levels and brain tissue energy supply, while preventing oxidative stress injury. These results should guide future explorations to elucidate acupuncture-based mechanisms for alleviating neuronal injury triggered by acute cerebral ischemia.

Novel PPAR-γ agonists as potential neuroprotective agents against Alzheimer's disease: rational design, synthesis, in silico evaluation, PPAR-γ binding assay and transactivation and expression studies

Alzheimer's disease (AD) is a neurological disorder. It is caused by accumulation of amyloid beta (Aβ) plaques and tau tangles, which gradually leads to cognitive decline and memory loss. Peroxisome proliferator-activated receptor gamma (PPAR-γ), a nuclear receptor, plays a significant role in regulating genes responsible for metabolism and inflammation. Studies have shown that PPAR-γ activation has neuroprotective effects, can potentially reduce inflammation and oxidative stress, and stimulates mitochondrial biogenesis. Current study presents the design, synthesis and in vitro evaluation of PPAR-γ agonists for AD that are tailored to optimize binding with the PPAR-γ receptor. The compounds 4a, 4h and 4j exhibited notable binding affinities towards PPAR-γ LBD, with IC50 values of 8.607, 9.242, and 5.974 μM, respectively, in TR-FRET binding assay. These compounds were cell proliferative and non-cytotoxic in a neuroblastoma cell line (SH-SY5Y). They also demonstrated dose-dependent PPAR-γ activation in transactivation assay. Their neuroprotective effect was studied based on their anti-inflammatory and anti-oxidant potential by reducing the levels of proinflammatory markers (TNF-α, IL-6 and IL-1β) and ROS in Aβ-induced SH-SY5Y neuroblastoma cells using a flow cytometry method. The synthesized compounds also showed interactions in molecular docking study with the PPAR-γ receptor and demonstrated good stability in MD simulation. Our results highlight that through activation of PPAR-γ, the compounds 4a, 4h and 4j offer neuroprotective effects by reducing neuroinflammation and oxidative stress, and hence, they may be considered lead molecules for treating AD.

SIRT1 Regulates Mitochondrial Damage in N2a Cells Treated with the Prion Protein Fragment 106-126 via PGC-1α-TFAM-Mediated Mitochondrial Biogenesis

Mitochondrial damage is an early and key marker of neuronal damage in prion diseases. As a process involved in mitochondrial quality control, mitochondrial biogenesis regulates mitochondrial homeostasis in neurons and promotes neuron health by increasing the number of effective mitochondria in the cytoplasm. Sirtuin 1 (SIRT1) is a NAD+-dependent deacetylase that regulates neuronal mitochondrial biogenesis and quality control in neurodegenerative diseases via deacetylation of a variety of substrates. In a cellular model of prion diseases, we found that both SIRT1 protein levels and deacetylase activity decreased, and SIRT1 overexpression and activation significantly ameliorated mitochondrial morphological damage and dysfunction caused by the neurotoxic peptide PrP106-126. Moreover, we found that mitochondrial biogenesis was impaired, and SIRT1 overexpression and activation alleviated PrP106-126-induced impairment of mitochondrial biogenesis in N2a cells. Further studies in PrP106-126-treated N2a cells revealed that SIRT1 regulates mitochondrial biogenesis through the PGC-1α-TFAM pathway. Finally, we showed that resveratrol resolved PrP106-126-induced mitochondrial dysfunction and cell apoptosis by promoting mitochondrial biogenesis through activation of the SIRT1-dependent PGC-1α/TFAM signaling pathway in N2a cells. Taken together, our findings further describe SIRT1 regulation of mitochondrial biogenesis and improve our understanding of mitochondria-related pathogenesis in prion diseases. Our findings support further investigation of SIRT1 as a potential target for therapeutic intervention of prion diseases.

Baicalein: A potential GLP-1R agonist improves cognitive disorder of diabetes through mitophagy enhancement

There is increasing evidence that the activation of glucagon-like peptide-1 receptor (GLP-1R) can be used as a therapeutic intervention for cognitive disorders. Here, we have screened GLP-1R targeted compounds from Scutellaria baicalensis, which revealed baicalein is a potential GLP-1R small-molecule agonist. Mitophagy, a selective autophagy pathway for mitochondrial quality control, plays a neuroprotective role in multiple cognitive impairment diseases. We noticed that Glp1r knock-out (KO) mice present cognitive impairment symptoms and appear worse in spatial learning memory and learning capacity in Morris water maze (MWM) test than their wide-type (WT) counterparts. Our mechanistic studies revealed that mitophagy is impaired in hippocampus tissue of diabetic mice and Glp1r KO mice. Finally, we verified that the cognitive improvement effects of baicalein on diabetic cognitive dysfunction occur through the enhancement of mitophagy in a GLP-1R-dependent manner. Our findings shed light on the importance of GLP-1R for cognitive function maintenance, and revealed the vital significance of GLP-1R for maintaining mitochondrial homeostasis. Furthermore, we identified the therapeutic potential of baicalein in the treatment of cognitive disorder associated with diabetes.

Methylated urolithin A, mitigates cognitive impairment by inhibiting NLRP3 inflammasome and ameliorating mitochondrial dysfunction in aging mice

Effective therapeutic interventions for elderly patients are lacking, despite advances in pharmacotherapy. Methylated urolithin A (mUro A), a modified ellagitannin (ET)-derived metabolite, exhibits anti-inflammatory, antioxidative, and anti-apoptotic effects. Current research has primarily investigated the neuroprotective effects of mUroA in aging mice and explored the underlying mechanisms. Our study used an in vivo aging model induced by d-galactose (D-gal) to show that mUro A notably improved learning and memory, prevented synaptic impairments by enhancing synaptic protein expression and increasing EPSCs, and reduced oxidative damage in aging mice. mUro A alleviated the activation of the NOD-like receptor thermal protein domain-associated protein 3 (NLRP3) inflammasome, leading to reduced glial cell activity and neuroinflammation in both accelerated aging and naturally senescent mouse models. Moreover, mUroA enhanced the activity of TCA cycle enzymes (PDH, CS, and OGDH), decreased 8-OHdG levels, and raised ATP and NAD+ levels within the mitochondria. At the molecular level, mUro A decreased phosphorylated p53 levels and increased the expression of peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α), thus enhancing mitochondrial function. In conclusion, mUro A alleviates cognitive impairment in aging mice by suppressing neuroinflammation through NLRP3 inflammasome inhibition and restoring mitochondrial function via the p53-PGC-1α pathway. This suggests its potential therapeutic agent for brain aging and aging-related diseases.

Unveiling the interplay of AMPK/SIRT1/PGC-1α axis in brain health: Promising targets against aging and NDDs

The escalating prevalence of neurodegenerative diseases (NDDs) within an aging global population presents a pressing challenge. The multifaceted pathophysiological mechanisms underlying these disorders, including oxidative stress, mitochondrial dysfunction, and neuroinflammation, remain complex and elusive. Among these, the AMPK/SIRT1/PGC-1α pathway emerges as a pivotal network implicated in neuroprotection against these destructive processes. This review sheds light on the potential therapeutic implications of targeting this axis, specifically emphasizing the promising role of flavonoids in mitigating NDD-related complications. Expanding beyond conventional pharmacological approaches, the exploration of non-pharmacological interventions such as exercise and calorie restriction (CR), coupled with the investigation of natural compounds, offers a beacon of hope. By strategically elucidating the intricate connections within these pathways, this review aims to pave the ways for novel multi-target agents and interventions, fostering a renewed optimism in the quest to combat and manage the debilitating impacts of NDDs on global health and well-being.

Diagnostic value of plasma SIRT1 levels and whole-brain gray matter volume in Parkinson's disease patients with cognitive impairment

OBJECTIVE

This study was designed to investigate the diagnostic value of plasma SIRT1 levels and whole-brain gray matter (GM) volume in Parkinson's disease (PD) patients with cognitive impairment.

METHODS

Automated enzymatic analysis was performed to measure plasma SIRT1 levels in 80 healthy controls and 77 PD patients. Motor symptoms and nonmotor symptoms in PD patients were assessed using the corresponding scales. A Siemens MAGNETOM Prisma 3 T MRI scanner was used to acquire images in 35 of 77 PD patients.

RESULTS

Plasma SIRT1 levels in PD patients were lower than those in healthy controls. Plasma SIRT1 levels were negatively correlated with the age, Unified Parkinson's Disease Rating Scale Part III (UPDRS-III) scores, anxiety, depression, excessive daytime sleepiness (EDS), quality of life, and especially cognitive impairment. Thus, it showed that plasma SIRT1 levels were relevant to visuospatial/executive function, memory, and language. Receiver-operating characteristic (ROC) analysis confirmed that plasma SIRT1 levels had good diagnostic accuracy for PD with anxiety and EDS. Furthermore, plasma SIRT1 levels had a significant positive correlation with GM volume in the whole brain, and ROC analysis confirmed that plasma SIRT1 levels and the total GM volume had good diagnostic accuracy for PD with cognitive impairment.

CONCLUSIONS

This study showed that plasma SIRT1 levels were correlated with the nonmotor symptoms of anxiety, depression, EDS, and especially cognitive impairment as well as the total GM volume. Furthermore, the combination of plasma SIRT1 levels and the total GM volume had good diagnostic accuracy for PD with cognitive impairment.

Daucosterol confers protection against T-2 toxin induced blood-brain barrier toxicity through the PGC-1α-mediated defensive response in vitro and in vivo

T-2 toxin is a common environmental pollutant and contaminant in food and animal feed that represents a great challenge to human and animal' health throughout the world. Using natural compounds to prevent the detrimental effects of T-2 toxin represents an attractive strategy. Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) is a critical regulator in various cellular processes. Recently, PGC-1α activation has been reported to confer protection against neurological injuries. We aimed to identify a potent PGC-1α activator from plants as a chemopreventive compound and to demonstrate the efficacy of the compound in attenuating T-2 toxin-induced blood-brain barrier (BBB) toxicity. We identified daucosterol, which binds directly to the 71-74 (-1100 to -1000 bp) position of the second promoter of human PGC-1α by hydrogen bonding. An in vitro and in vivo T-2 toxin induced BBB injury model revealed that this compound can protect against this injury by increasing transepithelial/transendothelial electrical resistance, reducing sodium fluorescein (NaF) infiltration and increasing the expression of tight junction-related proteins (zonula occludens-1 (ZO-1), occludin (OCLN), claudin-5 (CLDN5)) expression. In conclusion, we identified daucosterol as representing a novel of PGC-1α activators and illustrated the mechanism of specific binding site. Furthermore, we have demonstrated the feasibility of using natural compounds targeting PGC-1α as a therapeutic approach to protect humans from environmental insults that may occur daily such as lipopolysaccharide.

Peroxisom proliferator-activated receptor-γ coactivator-1α in neurodegenerative disorders: A promising therapeutic target

Neurodegenerative disorders (NDDs) are characterized by progressive loss of selectively vulnerable neuronal populations and myelin sheath, leading to behavioral and cognitive dysfunction that adversely affect the quality of life. Identifying novel therapies that attenuate the progression of NDDs would be of significance. Peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α), a widely expressed transcriptional regulator, modulates the expression of genes engaged in mitochondrial biosynthesis, metabolic regulation, and oxidative stress (OS). Emerging evidences point to the strong connection between PGC-1α and NDDs, suggesting its positive impaction on the progression of NDDs. Therefore, it is urgent to gain a deeper and broader understanding between PGC-1α and NDDs. To this end, this review presents a comprehensive overview of PGC-1α, including its basic characteristics, the post-translational modulations, as well as the interacting transcription factors. Secondly, the pathogenesis of PGC-1α in various NDDs, such as Alzheimer's (AD), Parkinson's (PD), and Huntington's disease (HD) is briefly discussed. Additionally, this study summarizes the underlying mechanisms that PGC-1α is neuroprotective in NDDs via regulating neuroinflammation, OS, and mitochondrial dysfunction. Finally, we briefly outline the shortcomings of current NDDs drug therapy, and summarize the functions and potential applications of currently available PGC-1α modulators (activator or inhibitors). Generally, this review updates our insight of the important role of PGC-1α on the development of NDDs, and provides a promising therapeutic target/ drug for the treatment of NDDs.

Protective effect of resveratrol on mitochondrial biogenesis during hyperoxia-induced brain injury in neonatal pups

BACKGROUND

Neonatal hyperoxic brain injury is caused by exposure to hyperphysiological oxygen content during the period of incomplete development of the oxidative stress defence system, resulting in a large number of reactive oxygen species (ROS) and causing damage to brain tissue. Mitochondrial biogenesis refers to the synthesis of new mitochondria from existing mitochondria, mostly through the PGC-1α/Nrfs/TFAM signalling pathway. Resveratrol (Res), a silencing information regulator 2-related enzyme 1 (Sirt1) agonist, has been shown to upregulate the level of Sirt1 and the expression of peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α). We speculate that Res has a protective effect on hyperoxia-induced brain injury through mitochondrial biogenesis.

METHODS

Sprague-Dawley (SD) pups were randomly divided into the nonhyperoxia (NN) group, the nonhyperoxia with dimethyl sulfoxide (ND) group, the nonhyperoxia with Res (NR) group, the hyperoxia (HN) group, the hyperoxia with dimethyl sulfoxide (HD) group, and the hyperoxia with Res (HR) group within 12 h after birth. The HN, HD, and HR groups were placed in a high-oxygen environment (80‒85%), and the other three groups were placed in the standard atmosphere. The NR and HR groups were given 60 mg/kg Res every day, the ND and HD groups were given the same dose of dimethyl sulfoxide (DMSO) every day, and the NN and HN groups were given the same dose of normal saline every day. On postnatal day (PN) 1, PN7, and PN14, brain samples were acquired for HE staining to assess pathology, TUNEL to detect apoptosis, and real-time quantitative polymerase chain reaction and immunoblotting to detect the expression levels of Sirt1, PGC-1α, nuclear respiratory factor 1 (Nrf1), nuclear respiratory factor 2 (Nrf2) and mitochondrial transcription factor A (TFAM) in brain tissue.

RESULTS

Hyperoxia induced brain tissue injury; increased brain tissue apoptosis; inhibited Sirt1, PGC-1α, Nrf1, Nrf2, TFAM mRNA expression in mitochondria; diminished the ND1 copy number and ND4/ND1 ratio; and decreased Sirt1, PGC-1α, Nrf1, Nrf2, and TFAM protein levels in the brain. In contrast, Res reduced brain injury and attenuated brain tissue apoptosis in neonatal pups and increased the levels of the corresponding indices.

CONCLUSION

Res has a protective effect on hyperoxia-induced brain injury in neonatal SD pups by upregulating Sirt1 and stimulating the PGC-1α/Nrfs/TFAM signalling pathway for mitochondrial biogenesis.

FGF19 improves sevoflurane-induced cognitive dysfunction in rats through the PGC-1α/BDNF/FNDC5 pathway

Postoperative cognitive dysfunction (POCD) is a serious central nervous system complication characterized by impaired memory, reduced information processing ability, and anxiety. Recently, the role of FGF19 in neurological diseases has been reported. However, the effect and mechanisms of FGF19 in improving symptoms of POCD remain unknown. This study aimed to identify the role and exploring the underlying mechanisms of FGF19 in POCD. Here, rats were separated into four different groups, including control, sevoflurane (sev), sev + AAV-empty, and sev + AAV-FGF19 group. Then, the Morris water maze (MWM) test was applied to identify the effect of FGF19 on POCD rats. The result proved that FGF19 improved sevoflurane induced cognitive dysfunction in rats. Subsequently, the expressions of TNF-α, IL-6, IL-1β, and IL-10 were detected to verify the anti-neuroinflammatory effects of FGF19 in POCD rats. Furthermore, DHE fluorescent staining assay showed that FGF19 could inhibit sevoflurane-induced oxidative stress in POCD rats. Besides, NISSL staining and TUNEL assay were applied to reveal that FGF19 could alleviate hippocampal neuron injury induced by sevoflurane in rats. Moreover, mechanistic studies confirmed that FGF19 improved symptoms of POCD by mediated PGC-1α/BDNF/FNDC5 pathway. Together, these results suggested that FGF19 improves sevoflurane-induced POCD in rats through the PGC-1α/BDNF/FNDC5 pathway.

Peroxisome proliferator-activated receptor (PPAR) agonists as a potential therapy for inherited metabolic disorders

Inherited metabolic disorders (IMDs) are genetic disorders that cause a disruption of a specific metabolic pathway leading to biochemical, clinical and pathophysiological sequelae. While the metabolite abnormalities in body fluids and tissues can usually be defined by directed or broad-spectrum metabolomic analysis, the pathophysiology of these changes is often not obvious. Mounting evidence has revealed that secondary mitochondrial dysfunction, mainly oxidative phosphorylation impairment and elevated reactive oxygen species, plays a pivotal role in many disorders. Peroxisomal proliferator-activated receptors (PPARs) consist of a group of nuclear hormone receptors (PPARα, PPARβ/δ, and PPARγ) that regulate multiple cellular functions and processes, including response to oxidative stress, inflammation, lipid metabolism, and mitochondrial bioenergetics and biogenesis. In this context, the activation of PPARs has been shown to stimulate oxidative phosphorylation and reduce reactive species levels. Thus, pharmacological treatment with PPAR activators, such as fibrates, has gained much attention in the last 15 years. This review summarizes preclinical (animal models and patient-derived cells) and clinical data on the effect of PPARs in IMDs.

Competing endogenous RNA (ceRNA) networks in Parkinson's disease: A systematic review

Parkinson's disease (PD) is a distinctive clinical syndrome with several causes and clinical manifestations. Aside from an infectious cause, PD is a rapidly developing neurological disorder with a global rise in frequency. Notably, improved knowledge of molecular pathways and the developing novel diagnostic methods may result in better therapy for PD patients. In this regard, the amount of research on ceRNA axes is rising, highlighting the importance of these axes in PD. CeRNAs are transcripts that cross-regulate one another via competition for shared microRNAs (miRNAs). These transcripts may be either coding RNAs (mRNAs) or non-coding RNAs (ncRNAs). This research used a systematic review to assess validated loops of ceRNA in PD. The Prisma guideline was used to conduct this systematic review, which entailed systematically examining the articles of seven databases. Out of 309 entries, forty articles met all criteria for inclusion and were summarized in the appropriate table. CeRNA axes have been described through one of the shared vital components of the axes, including lncRNAs such as NEAT1, SNHG family, HOTAIR, MALAT1, XIST, circRNAs, and lincRNAs. Understanding the multiple aspects of this regulatory structure may aid in elucidating the unknown causal causes of PD and providing innovative molecular therapeutic targets and medical fields.

Apelin-13 Improves Cognitive Impairment and Repairs Hippocampal Neuronal Damage by Activating PGC-1α/PPARγ Signaling

Alzheimer's disease (AD) is a complex neurodegenerative disease that is prevalent around the world. Both Apelin-13 and proliferator-activated receptor-γ (PPARγ)/PPARγ co-activator 1α (PGC-1α) are regarded as candidate targets for treating AD. The investigation examined whether Apelin-13 exerts neuroprotective effects via PGC-1α/PPARγ signaling. In this study, Apelin-13 improved cognitive deficits in AD mice, while SR-18,292 (a PGC-1α inhibitor) interfered with the therapeutic effects of Apelin-13. Mechanistically, Apelin-13, PGC-1α and PPARγ were decreased in AD mice and oxygen-glucose deprivation (OGD)-induced neuronal cells. Apelin-13 bound to PGC-1α and negatively regulated the expression of PGC-1α and PPARγ. In turn, PGC-1α accelerated the accumulation of Apelin-13 and PPARγ. Additionally, neuronal apoptosis was inhibited, and the abundance of apoptosis-related proteins (Bax, Bcl-2, and cleaved caspase 3) was induced. The content of reactive oxygen species (ROS), malondialdehyde (MDA) and superoxide dismutase (SOD) fluctuated. The level of inflammatory factors (interleukin-6, IL-6, IL-10, tumor necrosis factor-α, TNF-α) was regulated. In short, Apelin-13 exerted anti-apoptosis, anti-oxidant stress and anti-inflammatory effects. Interestingly, PGC-1α silencing promoted neuronal apoptosis, oxidant stress and inflammation, and overexpression of PGC-1α exhibited the opposite. More importantly, inhibition of PGC-1α attenuated Apelin-13-enhanced cognitive impairment and neuronal damage. Therefore, our findings suggested that Apelin-13 exerted neuroprotective effects in part via the PGC-1α/PPARγ pathway.

Mechanisms of mitochondrial respiratory adaptation

Mitochondrial energetic adaptations encompass a plethora of conserved processes that maintain cell and organismal fitness and survival in the changing environment by adjusting the respiratory capacity of mitochondria. These mitochondrial responses are governed by general principles of regulatory biology exemplified by changes in gene expression, protein translation, protein complex formation, transmembrane transport, enzymatic activities and metabolite levels. These changes can promote mitochondrial biogenesis and membrane dynamics that in turn support mitochondrial respiration. The main regulatory components of mitochondrial energetic adaptation include: the transcription coactivator peroxisome proliferator-activated receptor-γ (PPARγ) coactivator 1α (PGC1α) and associated transcription factors; mTOR and endoplasmic reticulum stress signalling; TOM70-dependent mitochondrial protein import; the cristae remodelling factors, including mitochondrial contact site and cristae organizing system (MICOS) and OPA1; lipid remodelling; and the assembly and metabolite-dependent regulation of respiratory complexes. These adaptive molecular and structural mechanisms increase respiration to maintain basic processes specific to cell types and tissues. Failure to execute these regulatory responses causes cell damage and inflammation or senescence, compromising cell survival and the ability to adapt to energetically demanding conditions. Thus, mitochondrial adaptive cellular processes are important for physiological responses, including to nutrient availability, temperature and physical activity, and their failure leads to diseases associated with mitochondrial dysfunction such as metabolic and age-associated diseases and cancer.

Apelin-13 attenuates depressive-like behaviors induced by chronic unpredictable mild stress via activating AMPK/PGC-1α/FNDC5/BDNF pathway

Chronic stress induces neuronal death and impairs hippocampal neurogenesis, thus leading to cognitive deficits and depressive-like behaviors. Our previous studies found that apelin-13, a novel neuropeptide, and its receptors can improve cognitive impairment and depressive-like behaviors in rats, but its mechanism remains unknown. The study aims to evaluate the underlying mechanism of apelin-13 on cognitive impairment and depressive-like behaviors. A 4-week chronic unpredictable mild stress (CUMS) is used to establish a rat model of depression. Apelin-13(2 ug/day) is administered daily to the rats during the last 1 week. Depressive-like behaviors, including tail suspension test (TST) and sucrose preference test (SPT), are performed. The cognitive functions are established by identify index of novel objects recognition test (NORT) and the number of crossing hidden platform in morris water maze (MWM). The neuronal death is measured by popidium iodide (PI) and flow cytometry. The activity of superoxide dismutase (SOD) and glutathione-peroxidase (GSH-PX) in the hippocampus are determined. The protein expressions of p-AMPK, AMPK, BDNF, FNDC5 and PGC-1α are examined. Golgi staining observed the spine dendritic arborization of the hippocampal cornu ammonis 1 (CA1) subregion. Results showed that apelin-13 improves cognitive impairment and ameliorates depressive-like behaviors. Moreover, apelin-13 significantly inhibits neuronal death via AMPK/PGC-1α/FNDC5/BDNF pathway. Taken together, apelin-13 could exert antidepressant effects via protecting neuron functions, which might be related to the activation of AMPK/PGC-1α/FNDC5/BDNF pathway.

Neuroprotective Function of Rasagiline and Selegiline, Inhibitors of Type B Monoamine Oxidase, and Role of Monoamine Oxidases in Synucleinopathies

Synucleinopathies are a group of neurodegenerative disorders caused by the accumulation of toxic species of α-synuclein. The common clinical features are chronic progressive decline of motor, cognitive, behavioral, and autonomic functions. They include Parkinson’s disease, dementia with Lewy body, and multiple system atrophy. Their etiology has not been clarified and multiple pathogenic factors include oxidative stress, mitochondrial dysfunction, impaired protein degradation systems, and neuroinflammation. Current available therapy cannot prevent progressive neurodegeneration and “disease-modifying or neuroprotective” therapy has been proposed. This paper presents the molecular mechanisms of neuroprotection by the inhibitors of type B monoamine oxidase, rasagiline and selegiline. They prevent mitochondrial apoptosis, induce anti-apoptotic Bcl-2 protein family, and pro-survival brain- and glial cell line-derived neurotrophic factors. They also prevent toxic oligomerization and aggregation of α-synuclein. Monoamine oxidase is involved in neurodegeneration and neuroprotection, independently of the catalytic activity. Type A monoamine oxidases mediates rasagiline-activated signaling pathways to induce neuroprotective genes in neuronal cells. Multi-targeting propargylamine derivatives have been developed for therapy in various neurodegenerative diseases. Preclinical studies have presented neuroprotection of rasagiline and selegiline, but beneficial effects have been scarcely presented. Strategy to improve clinical trials is discussed to achieve disease-modification in synucleinopathies.

Downstream Effects of Mutations in SOD1 and TARDBP Converge on Gene Expression Impairment in Patient-Derived Motor Neurons

Amyotrophic Lateral Sclerosis (ALS) is a progressive and fatal neurodegenerative disease marked by death of motor neurons (MNs) present in the spinal cord, brain stem and motor cortex. Despite extensive research, the reason for neurodegeneration is still not understood. To generate novel hypotheses of putative underlying molecular mechanisms, we used human induced pluripotent stem cell (hiPSCs)-derived motor neurons (MNs) from SOD1- and TARDBP (TDP-43 protein)-mutant-ALS patients and healthy controls to perform high-throughput RNA-sequencing (RNA-Seq). An integrated bioinformatics approach was employed to identify differentially expressed genes (DEGs) and key pathways underlying these familial forms of the disease (fALS). In TDP43-ALS, we found dysregulation of transcripts encoding components of the transcriptional machinery and transcripts involved in splicing regulation were particularly affected. In contrast, less is known about the role of SOD1 in RNA metabolism in motor neurons. Here, we found that many transcripts relevant for mitochondrial function were specifically altered in SOD1-ALS, indicating that transcriptional signatures and expression patterns can vary significantly depending on the causal gene that is mutated. Surprisingly, however, we identified a clear downregulation of genes involved in protein translation in SOD1-ALS suggesting that ALS-causing SOD1 mutations shift cellular RNA abundance profiles to cause neural dysfunction. Altogether, we provided here an extensive profiling of mRNA expression in two ALS models at the cellular level, corroborating the major role of RNA metabolism and gene expression as a common pathomechanism in ALS.

Estrogen-related receptor gamma regulates mitochondrial and synaptic genes and modulates vulnerability to synucleinopathy

Many studies implicate mitochondrial dysfunction as a key contributor to cell loss in Parkinson disease (PD). Previous analyses of dopaminergic (DAergic) neurons from patients with Lewy-body pathology revealed a deficiency in nuclear-encoded genes for mitochondrial respiration, many of which are targets for the transcription factor estrogen-related receptor gamma (Esrrg/ERRγ). We demonstrate that deletion of ERRγ from DAergic neurons in adult mice was sufficient to cause a levodopa-responsive PD-like phenotype with reductions in mitochondrial gene expression and number, that partial deficiency of ERRγ hastens synuclein-mediated toxicity, and that ERRγ overexpression reduces inclusion load and delays synuclein-mediated cell loss. While ERRγ deletion did not fully recapitulate the transcriptional alterations observed in postmortem tissue, it caused reductions in genes involved in synaptic and mitochondrial function and autophagy. Altogether, these experiments suggest that ERRγ-deficient mice could provide a model for understanding the regulation of transcription in DAergic neurons and that amplifying ERRγ-mediated transcriptional programs should be considered as a strategy to promote DAergic maintenance in PD.

SUMO-specific protease SENP3 enhances MDM2-mediated ubiquitination of PARIS/ZNF746 in HeLa cells

The transcriptional repressor PARIS, a substrate of the ubiquitin E3 ligase parkin, represses the expression of the transcriptional co-activator, PGC-1α gene, and is involved in several pathological processes, including neurodegenerative disease and cancers. We have previously shown that SUMOylation of PARIS play an important role in its transcriptional repression activity. In addition, RNF4-mediated ubiquitination of SUMO2/3-conjugated PARIS is required for the control of PARIS-mediated transcriptional repression in HeLa cells that lack parkin expression. However, little is known about how PARIS ubiquitination and degradation are regulated in parkin-deficient cells. Here, we report that the deSUMOylase SENP3 interacted with PARIS and enhanced the ubiquitination of PARIS independently of its SUMOylation in HeLa cells. SENP3-enhanced PARIS ubiquitination mainly contributed to its proteasomal degradation, and required the oncogenic E3 ubiquitin ligase MDM2. MDM2 knockdown by small interfering RNA or expression of a dominant-negative MDM2 mutant inhibited the ubiquitination of PARIS. We further found that MDM2 activation via the PI3K/AKT pathway was involved in PARIS ubiquitination. Taken together, these results suggest that PARIS ubiquitination through SENP3-mediated MDM2 activation may control its functions in parkin-deficient cells.

Novel role of COX6c in the regulation of oxidative phosphorylation and diseases

Cytochrome c oxidase subunit VIc (COX6c) is one of the most important subunits of the terminal enzyme of the respiratory chain in mitochondria. Numerous studies have demonstrated that COX6c plays a critical role in the regulation of oxidative phosphorylation (OXPHOS) and energy production. The release of COX6c from the mitochondria may be a hallmark of the intrinsic apoptosis pathway. Moreover, The changes in COX6c expression are widespread in a variety of diseases and can be chosen as a potential biomarker for diagnosis and treatment. In light of its exclusive effects, we present the elaborate roles that COX6c plays in various diseases. In this review, we first introduced basic knowledge regarding COX6c and its functions in the OXPHOS and apoptosis pathways. Subsequently, we described the regulation of COX6c expression and activity in both positive and negative ways. Furthermore, we summarized the elaborate roles that COX6c plays in various diseases, including cardiovascular disease, kidney disease, brain injury, skeletal muscle injury, and tumors. This review highlights recent advances and provides a comprehensive summary of COX6c in the regulation of OXPHOS in multiple diseases and may be helpful for drug design and the prediction, diagnosis, treatment, and prognosis of diseases.

Metabolomic Assay, Computational Screening, and Pharmacological Evaluation of Caulerpa racemosa as an Anti-obesity With Anti-aging by Altering Lipid Profile and Peroxisome Proliferator-Activated Receptor-γ Coactivator 1-α Levels

Obesity is associated with an accelerated aging process, which prevents healthy aging. Both obesity and aging were manifested in the peroxisome proliferator-activated receptor-γ coactivator α (PGC-1α) level. These studies fulfill the scientific gap in assembled pharmacological activity assay of Caulerpa racemosa done in a previous preclinical trial. Six major compounds from sea grape (C. racemosa) extract were evaluated using an in silico approach against human pancreatic lipase, a-glucosidase, and a-amylase to predict prospective anti-obesity candidates. The lipase inhibitory activity of the extract reached 90.30 ± 0.40%, 1.75% lower than orlistat. The a-amylase inhibitory assay of the extract was 84.07 ± 5.28%, while the inhibitory activity against a-glucosidase was 81.67 ± 1.54%; both were lower than acarbose. We observe the effect of C. racemosa extract as anti-obesity with anti-aging by evaluating the obesity parameters in the human body for a 4-week period. There was a significant decrease in blood glucose, total cholesterol, low-density lipoprotein (LDL), triglycerides (TG), waist circumference, waist-hip ratio, and body weight (p < 0.05); PGC-1α and high-density lipoprotein (HDL) increased significantly (p = 0.000), in Group B when compared with Group A. Our study revealed that sea grape extract is a potent anti-obesity with an anti-aging reagent that does not produce any significant adverse effects.

Berberine Ameliorates Cognitive Disorder via GSK3β/PGC-1α Signaling in APP/PS1 Mice

Previous studies have revealed that Berberine (BBR) had therapeutic effects on Alzheimer's disease (AD). However, the underlying mechanism of BBR in the treatment of AD is unclear. The study was to investigate whether berberine ameliorates cognitive disorder in AD by regulating on GSK3β/PGC-1α signaling pathway. APP/PS1 mice were treated with BBR (50 mg/kg and 100 mg/kg) for 4 mo, and the cognitive function of mice was tested by Morris water maze. The levels of inflammatory cytokines IL-1β, TNF-α, and IL-6 in hippocampus of mice were detected by ELISA kits. The damage of neuronal in hippocampal CA1 was detected by Nissl staining. The tau and GSK3β protein were detected by western blot. The results showed that BBR treatment obviously improved spatial cognitive function of APP/PS1 mice. Meanwhile, the pro-inflammatory cytokines were decreased in hippocampus by the administration of BBR. Additionally, BBR significantly alleviated neuronal damage and reduced the levels of hyperphosphorylated tau at sites of Thr205 and Thr231 in hippocampus. Importantly, BBR inhibited the activity of GSK3β and increased the expression of PGC-1α. Consequently, our results demonstrates that BBR could improve the cognitive function by inhibiting the tau hyperphosphorylation and neuroinflammation. These beneficial effects of BBR may be attributed to the regulation of GSK3β/PGC-1α signaling pathway in APP/PS1 mice. These findings reveal a vital role for GSK3β/PGC-1α signaling pathway in retarding cognitive disorder, indicating that PGC-1α might be a potential target for the treatment of AD.

Molecular Pathophysiological Mechanisms in Huntington's Disease

Huntington’s disease is an inherited neurodegenerative disease described 150 years ago by George Huntington. The genetic defect was identified in 1993 to be an expanded CAG repeat on exon 1 of the huntingtin gene located on chromosome 4. In the following almost 30 years, a considerable amount of research, using mainly animal models or in vitro experiments, has tried to unravel the complex molecular cascades through which the transcription of the mutant protein leads to neuronal loss, especially in the medium spiny neurons of the striatum, and identified excitotoxicity, transcriptional dysregulation, mitochondrial dysfunction, oxidative stress, impaired proteostasis, altered axonal trafficking and reduced availability of trophic factors to be crucial contributors. This review discusses the pathogenic cascades described in the literature through which mutant huntingtin leads to neuronal demise. However, due to the ubiquitous presence of huntingtin, astrocytes are also dysfunctional, and neuroinflammation may additionally contribute to Huntington’s disease pathology. The quest for therapies to delay the onset and reduce the rate of Huntington’s disease progression is ongoing, but is based on findings from basic research.

Sphingosine-1-phosphate in mitochondrial function and metabolic diseases

Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid metabolite. The past decade has witnessed exponential growth in the field of S1P research, partly attributed to drugs targeting its receptors or kinases. Accumulating evidence indicates that changes in the S1P axis (i.e., S1P production, transport, and receptors) may modify metabolism and eventually mediate metabolic diseases. Dysfunction of the mitochondria on a master monitor of cellular metabolism is considered the leading cause of metabolic diseases, with aberrations typically induced by abnormal biogenesis, respiratory chain complex disorders, reactive oxygen species overproduction, calcium deposition, and mitophagy impairment. Accordingly, we discuss decades of investigation into changes in the S1P axis and how it controls mitochondrial function. Furthermore, we summarize recent scientific advances in disorders associated with the S1P axis and their involvement in the pathogenesis of metabolic diseases in humans, including type 2 diabetes mellitus and cardiovascular disease, from the perspective of mitochondrial function. Finally, we review potential challenges and prospects for S1P axis application to the regulation of mitochondrial function and metabolic diseases; these data may provide theoretical guidance for the treatment of metabolic diseases.

Circular RNAs: Emblematic Players of Neurogenesis and Neurodegeneration

In the fascinating landscape of non-coding RNAs (ncRNAs), circular RNAs (circRNAs) are peeping out as a new promising and appreciated class of molecules with great potential as diagnostic and prognostic biomarkers. They come from circularization of single-stranded RNA molecules covalently closed and generated through alternative mRNA splicing. Dismissed for many years, similar to aberrant splicing by-products, nowadays, their role has been regained. They are able to regulate the expression of linear mRNA transcripts at different levels acting as miRNA sponges, interacting with ribonucleoproteins or exerting a control on gene expression. On the other hand, being extremely conserved across phyla and stable, cell and tissue specific, mostly abundant than the linear RNAs, it is not surprising that they should have critical biological functions. Curiously, circRNAs are particularly expressed in brain and they build up during aging and age-related diseases. These extraordinary peculiarities make circRNAs potentially suitable as promising molecular biomarkers, especially of aging and neurodegenerative diseases. This review aims to explore new evidence on circRNAs, emphasizing their role in aging and pathogenesis of major neurodegenerative disorders, Alzheimer's disease, frontotemporal dementia, and Parkinson's diseases with a look toward their potential usefulness in biomarker searching.

Sodium butyrate attenuates rotenone-induced toxicity by activation of autophagy through epigenetically regulating PGC-1α expression in PC12 cells

Short-chain fatty acids (SCFAs) are considered the key molecular link between gut microbiota and pathogenesis of Parkinson's disease (PD). However, the role of SCFAs in PD pathogenesis is controversial. Autophagy is important for the degradation of α-synuclein, which is critical to the development of PD. However, whether SCFAs can regulate autophagy in PD remains unknown. We aimed to investigate the role of SCFAs and explore the potential mechanisms in rat dopaminergic PC12 cells treated with rotenone. Expression levels of α-synuclein, peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) and microtubule-associated protein 1 light chain 3 beta (LC3B)-II were detected by Western blot. Histone acetylation levels at PGC-1α promoter region were measured using chromatin immunoprecipitation-quantitative polymerase chain reaction (ChIP-qPCR). Among the three SCFAs, sodium butyrate (NaB) protected against rotenone-induced toxicity. NaB activated autophagy pathway and reduced rotenone-induced α-synuclein expression through the activation of autophagy. Notably, NaB activated autophagy pathway through upregulating PGC-1α expression. More importantly, NaB promoted the levels of histone 3 lysine 9 acetylation (H3K9Ac) and histone 3 lysine 27 acetylation (H3K27Ac) at PGC-1α promoter region, indicating that NaB promotes PGC-1α expression via histone acetylation modification. In conclusion, NaB can protect against rotenone-induced toxicity through activation of the autophagy pathway by upregulating PGC-1α expression via epigenetic modification.

Glitazone Treatment Rescues Phenotypic Deficits in a Fly Model of Gaucher/Parkinson's Disease

Parkinson’s Disease (PD) is the most common movement disorder, and the strongest genetic risk factor for PD is mutations in the glucocerebrosidase gene (GBA). Mutations in GBA also lead to the development of Gaucher Disease (GD), the most common type of lysosomal storage disorder. Current therapeutic approaches fail to address neurological GD symptoms. Therefore, identifying therapeutic strategies that improve the phenotypic traits associated with GD/PD in animal models may provide an opportunity for treating neurological manifestations of GD/PD. Thiazolidinediones (TZDs, also called glitazones) are a class of compounds targeted for the treatment of type 2 diabetes, and have also shown promise for the treatment of neurodegenerative disease, including PD. Here, we tested the efficacy of glitazone administration during development in a fly GD model with deletions in the GBA homolog, dGBA1b (GBA1^ΔTT/ΔTT). We observed an optimal dose of pioglitazone (PGZ) at a concentration of 1 μM that reduced sleep deficits, locomotor impairments, climbing defects, and restoration of normal protein levels of Ref(2)P, a marker of autophagic flux, in GBA1^ΔTT/ΔTT mutant flies, compared to GBA1^+/+ control flies. These data suggest that PGZ may represent a potential compound with which to treat GD/PD by improving function of lysosomal-autophagy pathways, a cellular process that removes misfolded or aggregated proteins.

Recent advances in lentiviral vectors for gene therapy

Lentiviral vectors (LVs), derived from human immunodeficiency virus, are powerful tools for modifying the genes of eukaryotic cells such as hematopoietic stem cells and neural cells. With the extensive and in-depth studies on this gene therapy vehicle over the past two decades, LVs have been widely used in both research and clinical trials. For instance, third-generation and self-inactive LVs have been used to introduce a gene with therapeutic potential into the host genome and achieve targeted delivery into specific tissue. When LVs are employed in leukemia, the transduced T cells recognize and kill the tumor B cells; in β-thalassemia, the transduced CD34⁺ cells express normal β-globin; in adenosine deaminase-deficient severe combined immunodeficiency, the autologous CD34⁺ cells express adenosine deaminase and realize immune reconstitution. Overall, LVs can perform significant roles in the treatment of primary immunodeficiency diseases, hemoglobinopathies, B cell leukemia, and neurodegenerative diseases. In this review, we discuss the recent developments and therapeutic applications of LVs. The safe and efficient LVs show great promise as a tool for human gene therapy.

Glitazones Activate PGC-1α Signaling via PPAR-γ: A Promising Strategy for Antiparkinsonism Therapeutics

Understanding various aspects of Parkinson's disease (PD) by researchers could lead to a better understanding of the disease and provide treatment alternatives that could significantly improve the quality of life of patients suffering from neurodegenerative disorders. Significant progress has been made in recent years toward this goal, but there is yet no available treatment with confirmed neuroprotective effects. Recent studies have shown the potential of PPARγ agonists, which are the ligand activated transcriptional factor of the nuclear hormone superfamily, as therapeutic targets for various neurodegenerative disorders. The activation of central PGC-1α mediates the potential role against neurogenerative diseases like PD, Huntington's disease, Alzheimer's disease, and amyotrophic lateral sclerosis. Further understanding the mechanism of neurodegeneration and the role of glitazones in the activation of PGC-1α signaling could lead to a novel therapeutic interventions against PD. Keeping this aspect in focus, the present review highlights the pathogenic mechanism of PD and the role of glitazones in the activation of PGC-1α via PPARγ for the treatment of neurodegenerative disorders.

Medioresinol as a novel PGC-1α activator prevents pyroptosis of endothelial cells in ischemic stroke through PPARα-GOT1 axis

AIM

Brain microvascular endothelial cells (BMVECs), as the important structure of blood-brain barrier (BBB), play a vital role in ischemic stroke. Pyroptosis of different cells in the brain may aggravate cerebral ischemic injury, and PGC-1α plays a major role in pyroptosis. However, it is not known whether BMVECs undergo pyroptosis after ischemic stroke and whether PGC-1α activator Medioresinol (MDN) we discovered may be useful against pyroptosis of endothelial cells and ischemic brain injury.

METHODS

For in vitro experiments, the bEnd.3 cells and BMVECs under oxygen and glucose-deprivation (OGD) were treated with or without MDN, and the LDH release, tight junction protein degradation, GSDMD-NT membrane location and pyroptosis-associated proteins were evaluated. For in vivo experiments, mice underwent transient middle cerebral artery occlusion (tMCAO) for ischemia model, and the neuroprotective effects of MDN were measured by infarct volume, the permeability of BBB and pyroptosis of BMVECs. For mechanistic study, effects of MDN on the accumulation of phenylalanine, mitochondrial reactive oxygen species (mtROS) were tested by untargeted metabolomics and MitoSOX Red probe, respectively.

RESULTS

BMVECs underwent pyroptosis after ischemia. MDN dose-dependently activated PGC-1α, significantly reduced pyroptosis, mtROS and the expressions of pyroptosis-associated proteins (NLRP3, ASC, cleaved caspase-1, IL-1β, GSDMD-NT), and increased ZO-1 and Occludin protein expressions in BMVECs. In tMCAO mice, MDN remarkably reduced brain infarct volume and the permeability of BBB, inhibited pyroptosis of BMVECs, and promoted long-term neurobehavioral functional recovery. Mechanistically, MDN promoted the interaction of PGC-1α with PPARα to increase PPARα nuclear translocation and transcription activity, further increased the expression of GOT1 and PAH, resulting in enhanced phenylalanine metabolism to reduce the ischemia-caused phenylalanine accumulation and mtROS and further ameliorate pyroptosis of BMVECs.

CONCLUSION

In this study, we for the first time discovered that pyroptosis of BMVECs was involved in the pathogenesis of ischemic stroke and MDN as a novel PGC-1α activator could ameliorate the pyroptosis of endothelial cells and ischemic brain injury, which might attribute to reduction of mtROS through PPARα/GOT1 axis in BMVECs. Taken together, targeting endothelial pyroptosis by MDN may provide alternative therapeutics for brain ischemic stroke.

Metformin prevents stroke damage in non-diabetic female mice with chronic kidney disease

Chronic kidney disease (CKD) worsens ischemic stroke severity in both patients and animals. In mice, these poorer functional outcomes are associated with decreased brain activity of AMP-activated protein kinase (AMPK), a molecule that recently emerged as a potential therapeutic target for ischemic stroke. The antidiabetic drug metformin, a well-known activator of AMPK, has improved stroke outcomes in diabetic patients with normal renal function. We investigated whether chronic metformin pre-conditioning can rescue AMPK activity and prevent stroke damage in non-diabetic mice with CKD. Eight-week-old female C57BL/6J mice were assigned to CKD or SHAM groups. CKD was induced through right kidney cortical electrocautery, followed by left total nephrectomy. Mice were then allocated to receive metformin (200 mg/kg/day) or vehicle for 5 weeks until stroke induction by transient middle cerebral artery occlusion (tMCAO). The infarct volumes were lower in CKD mice exposed to metformin than in vehicle-treated CKD mice 24 h after tMCAO. Metformin pre-conditioning of CKD mice improved their neurological score, grip strength, and prehensile abilities. It also enhanced AMPK activation, reduced apoptosis, increased neuron survival and decreased microglia/macrophage M1 signature gene expression as well as CKD-induced activation of the canonical NF-κB pathway in the ischemic lesions of CKD mice.

Dysiarenone from Marine Sponge Dysidea arenaria Attenuates ROS and Inflammation via Inhibition of 5-LOX/NF-κB/MAPKs and Upregulation of Nrf-2/OH-1 in RAW 264.7 Macrophages

Background

Marine natural products harbor a variety of pharmacological activities, and the sea species have been becoming a main source of new drug candidate. In pursuit of safer and more effective anti-inflammation drug, the anti-inflammatory activities, anti-oxygenation effects and underlying molecular mechanisms of compound dysiarenone from Dysidea arenaria were investigated via LPS-induced RAW 264.7 cell model.

Methods

Firstly, RAW 264.7 cells have been stimulated with LPS and treated with dysiarenone, and the cell viability of the LPS-treated RAW 264.7 cells was examined. One-step method, DCFH-DA fluorescence probe method was used to detect reactive oxygen species (ROS). The modulation of dysiarenone on anti-inflammation was detected by enzyme-linked immunosorbent assay by measuring the release of inflammatory cytokines (TNF-α and IL-6), and inflammatory mediators (LTB4). Further, the underlying anti-inflammatory mechanism of dysiarenone was explored by determining the expression of inducible 5-LOX, MAPKs, p-Akt, and p-NF-κB p65. Oxidative stress is tightly connected with inflammation, which was also evaluated through nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (OH-1) signaling pathway.

Results

Our study unraveled that dysiarenone between 2 and 8 µM reduces the inflammation responses via suppressing the production of inflammatory cytokines (TNF-α and IL-6) and inflammatory mediators (LTB₄). Dysiarenone down-regulated the protein levels of inducible 5-LOX via the inhibition of phosphorylation of MAPKs (including p38, ERK), Akt and NF-κB p65. Additionally, dysiarenone decreases ROS accumulation by upregulating HO-1 expression via nuclear translocation of Nrf2.

Conclusion

In conclusion, we demonstrated that dysiarenone possesses anti-inflammation and anti-oxidation activity via inhibiting 5-LOX/NF-κB/MAPK and Nrf2/HO-1 signaling pathway. Dysiarenone might be a promising lead compound for inflammatory diseases.

PGC-1α protects from myocardial ischaemia-reperfusion injury by regulating mitonuclear communication

The recovery of blood supply after a period of myocardial ischaemia does not restore the heart function and instead results in a serious dysfunction called myocardial ischaemia‐reperfusion injury (IRI), which involves several complex pathophysiological processes. Mitochondria have a wide range of functions in maintaining the cellular energy supply, cell signalling and programmed cell death. When mitochondrial function is insufficient or disordered, it may have adverse effects on myocardial ischaemia‐reperfusion and therefore mitochondrial dysfunction caused by oxidative stress a core molecular mechanism of IRI. Peroxisome proliferator‐activated receptor gamma co‐activator 1α (PGC‐1α) is an important antioxidant molecule found in mitochondria. However, its role in IRI has not yet been systematically summarized. In this review, we speculate the role of PGC‐1α as a key regulator of mitonuclear communication, which may interacts with nuclear factor, erythroid 2 like ‐1 and ‐2 (NRF‐1/2) to inhibit mitochondrial oxidative stress, promote the clearance of damaged mitochondria, enhance mitochondrial biogenesis, and reduce the burden of IRI.

Competing Endogenous RNA Networks as Biomarkers in Neurodegenerative Diseases

Protein aggregation is classically considered the main cause of neuronal death in neurodegenerative diseases (NDDs). However, increasing evidence suggests that alteration of RNA metabolism is a key factor in the etiopathogenesis of these complex disorders. Non-coding RNAs are the major contributor to the human transcriptome and are particularly abundant in the central nervous system, where they have been proposed to be involved in the onset and development of NDDs. Interestingly, some ncRNAs (such as lncRNAs, circRNAs and pseudogenes) share a common functionality in their ability to regulate gene expression by modulating miRNAs in a phenomenon known as the competing endogenous RNA mechanism. Moreover, ncRNAs are found in body fluids where their presence and concentration could serve as potential non-invasive biomarkers of NDDs. In this review, we summarize the ceRNA networks described in Alzheimer's disease, Parkinson's disease, multiple sclerosis, amyotrophic lateral sclerosis and spinocerebellar ataxia type 7, and discuss their potential as biomarkers of these NDDs. Although numerous studies have been carried out, further research is needed to validate these complex interactions between RNAs and the alterations in RNA editing that could provide specific ceRNET profiles for neurodegenerative disorders, paving the way to a better understanding of these diseases.

The Critical Role of SIRT1 in Parkinson's Disease: Mechanism and Therapeutic Considerations

Silence information regulator 1 (SIRT1), a member of the sirtuin family, targets histones and many non-histone proteins and participates in various physiological functions. The enzymatic activity of SIRT1 is decreased in patients with Parkinson’s disease (PD), which may reduce their ability to resist neuronal damage caused by various neurotoxins. As far as we know, SIRT1 can induce autophagy by regulating autophagy related proteins such as AMP-activated protein kinase, light chain 3, mammalian target of rapamycin, and forkhead transcription factor 1. Furthermore, SIRT1 can regulate mitochondrial function and inhibit oxidative stress mainly by maintaining peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) in a deacetylated state and thus maintaining a constant level of PGC-1α. Other studies have demonstrated that SIRT1 may play a role in the pathophysiology of PD by regulating neuroinflammation. SIRT1 deacetylases nuclear factor-kappa B and thus reduces its transcriptional activity, inhibits inducible nitric oxide synthase expression, and decreases tumor necrosis factor-alpha and interleukin-6 levels. SIRT1 can also upregulate heat shock protein 70 by deacetylating heat shock factor 1 to increase the degradation of α-synuclein oligomers. Few studies have focused on the relationship between SIRT1 single nucleotide polymorphisms and PD risk, so this topic requires further research. Based on the neuroprotective effects of SIRT1 on PD, many in vitro and in vivo experiments have demonstrated that some SIRT1 activators, notably resveratrol, have potential neuroprotective effects against dopaminergic neuronal damage caused by various neurotoxins. Thus, SIRT1 plays a critical role in PD development and might be a potential target for PD therapy.

Pretreatment of Ascorbic Acid Inhibits MPTP-Induced Astrocytic Oxidative Stress through Suppressing NF-κB Signaling

Astrocytes are a major constituent of the central nervous system (CNS). Astrocytic oxidative stress contributes to the development of Parkinson's disease (PD). Maintaining production of antioxidant and detoxification of reactive oxygen and nitrogen species (ROS/RNS) in astrocytes is critical to prevent PD. Study has illuminated that ascorbic acid (AA) stimulates dopamine synthesis and expression of tyrosine hydroxylase in human neuroblastoma cells. However, the role and regulatory mechanisms of AA on detoxification of astrocytes are still unclear. The purpose of our study is in-depth study of the regulatory mechanism of AA on detoxification of astrocytes. We found that AA pretreatment decreased the expression of ROS and inducible nitric oxide synthase (iNOS) in MPP⁺-treated astrocytes. In contrast, the expression levels of antioxidative substances—including superoxide dismutase (SOD), glutathione (GSH), and glutamate-cysteine ligase modifier (GCLM) subunit—were upregulated after AA pretreatment in MPP⁺-treated astrocytes. However, inhibition of NF-κB prevented such AA induced increases in antioxidative substances following MPP⁺ treatment in astrocytes, suggesting that AA improved antioxidative function of astrocytes through inhibiting NF-κB-mediated oxidative stress. Furthermore, in vivo studies revealed that AA preadministration also suppressed NF-κB and upregulated the expression levels of antioxidative substances in the midbrain of MPTP-treated mice. Additionally, pretreatment of AA alleviated MPTP-induced PD-like pathology in mice. Taken together, our results demonstrate that preadministration of AA improves the antioxidative function of astrocytes through suppressing NF-κB signaling, following alleviated the pathogenesis of PD which induced by MPTP. Hence, our findings elucidate a novel protective mechanism of AA in astrocytes.

Mitochondrial Markers in Aging and Primary Open-Angle Glaucoma

This review focuses on recent progress in understanding the role of mitochondrial markers in the context of mitochondrial dysfunction in glaucoma and discussing new therapeutic approaches to modulate mitochondrial function and potentially lead to improved outcomes in glaucoma.

A natural product solution to aging and aging-associated diseases

Aging is a natural biological progress accompanied by the gradual decline in physiological functions, manifested by its close association with an increased incidence of human diseases and higher vulnerability to death. Those diseases include neurological disorders, cardiovascular diseases, diabetes, and cancer, many of which are currently without effective cures. Even though aging is inevitable, there are still interventions that can be developed to prevent/delay the onset and progression of those aging-associated diseases and extend healthspan and/or lifespan. Here, we review decades of research that reveals the molecular pathways underlying aging and forms the biochemical basis for anti-aging drug development. Importantly, due to the vast chemical space of natural products and the rich history of herb medicines in treating human diseases documented in different cultures, natural products have played essential roles in aging research. Using several of the most promising natural products and their derivatives as examples, we discuss how natural products serve as an inspiration resource that helped the identification of key components/pathways underlying aging, their mechanisms of action inside the cell, and the functional scaffolds or targeting mechanisms that can be learned from natural products for drug engineering and optimization. We argue that natural products might eventually provide a solution to aging and aging-associated diseases.

Urban particulate matter disturbs the equilibrium of mitochondrial dynamics and biogenesis in human vascular endothelial cells

Since ambient particulate matter (APM) is closely related to cardiovascular damage with mitochondria being its potential targets, this study was designed to explore the impact of APM on mitochondrial homeostasis, especially on mitochondrial dynamics and biogenesis in human vascular endothelial cells, using a kind of standard material, PM SRM1648a. As a result, internalized particles lead to mitochondrial dysfunction in EA.hy926 human endothelial cells, including mitochondrial reactive oxygen species (mtROS) overproduction, mitochondrial membrane potential (MMP) reduction and adenosine triphosphate (ATP) inhibition, coupled with additional release of mitochondrial DNA (mtDNA) into the cytosol. Moreover, morphological and structural changes in mitochondria are observed in response to PM SRM1648a. In that aspect, according to the evidence of shorter fragmented mitochondria dispersed throughout the cytoplasm, along with aberrant upregulation of fission-related mRNAs/proteins, the mitochondria exhibit a fission phenotype shifting from intact reticular network to fragmentized punctate shapes. Mechanistically, PM SRM1648a facilitates phosphorylation of DRP1 at Ser616 in HUVECs, and triggers its dephosphorylation at Ser637 residue in both EA.hy926 and HUVECs, which are supportive events for mitochondrial fission during particle exposure. Additionally, suppression of a master energy modulator, PGC-1α, reveals that PM SRM1648a has the ability to impair mitochondrial biogenesis. Collectively, it could be well concluded that PM SRM1648a interferes with the equilibrium of mitochondrial dynamics and biogenesis, which is likely to play a pivotal role in mitochondrial dysfunction driven by particles, eventually contributing to endothelial cell damage. Of note, it is more reasonable to conduct risk assessment from both cellular level and subcellular structures, among which mitochondria-targeted toxicity supplements more comprehensive understanding of APM inducible vascular toxicity.

Neuroprotective and neuro-survival properties of safinamide against methamphetamine-induced neurodegeneration: Hypothetic possible role of BDNF/TrkB/PGC-1α signaling pathway and mitochondrial uncoupling protein -2(UCP-2)

Methamphetamine is a behavioral psychostimulant that has a high potential for misuse and induction of neurotoxicity. Safinamide is a novel inhibitor of monoamine oxidase B (MAOB) with neuroprotective properties. Methamphetamine abuse causes dysfunction in the respiratory chain of the mitochondria, but the specific signaling mechanism and role of the uncoupling protein-2(UCP-2) remain unclear. As we know, some indirect evidence indicates that neurodegeneration can be caused by inhibition of the brain-derived neurotrophic factor (BDNF) receptor, TrkB and its downstream signaling pathway, such as the PGC-1α protein. Neuroprotective strategies and approaches to the management, treatment or prevention of methamphetamine-induced neurodegeneration by modulating BDNF / TrkB / PGC-1α-UCP-2 can be considered as novel therapeutic approaches to these psychostimulant neurochemical and neurobehavioral approaches. Previous studies have shown that safinamide, a monoamine oxidase-B (MAOB) inhibitor, can function as a neuroprotective agent and inhibit the neurodegenerative process especially in Parkinson's disease but its impact on other neurodegenerative processes and drug-induced neurotoxicity remain unclear. Although there is some evidence that BDNF / TrkB / PGC-1α-UCP-2 signaling pathway and mitochondrial UCP-2 mediated safinamide induced neuroprotection but it's exact and precise mechanism of action and neuroprotective effects in neurodegenerative disorder and the protective properties against methamphetamine induced neurodegeneration and the role of BDNF / TrkB / PGC-1α signaling pathway and role of mitochondrial UCP-2 in this process have not yet been clarified. Therefore, in subjects addicted to methamphetamine, we hypothesized that safinamide will provide neuroprotection against methamphetamine-prompted neurodegeneration, and it appears that BDNF / TrkB / PGC-1α signaling pathway and mitochondrial UCP-2 are likely to play a critical role.

RNF4-mediated SUMO-targeted ubiquitination relieves PARIS/ZNF746-mediated transcriptional repression

The transcriptional repressor PARIS, which is a substrate of the ubiquitin E3 ligase parkin, represses the expression of the transcriptional co-activator, PGC-1α. However, little is known about how its repression activity is regulated. We have previously shown that PARIS is SUMOylated, and this SUMOylation plays an important role in regulating its transcriptional repression activity. In this study, we demonstrated that PARIS SUMOylation induced its ubiquitination and subsequent proteasomal degradation, which was mediated by the SUMO-targeted ubiquitin ligase RNF4. Reporter gene assays revealed that co-expression of SUMO3 and RNF4 relieved PARIS-mediated transcriptional repression. Conversely, the SUMO E3 ligase PIASy inhibited the RNF4-mediated ubiquitination of PARIS and blocked the RNF4-mediated relief of PARIS-mediated transcriptional repression. These results suggest that RNF4 regulates PARIS ubiquitination to control its transcriptional repression activity.

The Novel Role of PPAR Alpha in the Brain: Promising Target in Therapy of Alzheimer's Disease and Other Neurodegenerative Disorders

Peroxisome proliferator activated receptor alpha (PPAR-α) belongs to the family of ligand-regulated nuclear receptors (PPARs). These receptors after heterodimerization with retinoid X receptor (RXR) bind in promotor of target genes to PPAR response elements (PPREs) and act as a potent transcription factors. PPAR-α and other receptors from this family, such as PPAR-β/δ and PPAR-γ are expressed in the brain and other organs and play a significant role in oxidative stress, energy homeostasis, mitochondrial fatty acids metabolism and inflammation. PPAR-α takes part in regulation of genes coding proteins that are involved in glutamate homeostasis and cholinergic/dopaminergic signaling in the brain. Moreover, PPAR-α regulates expression of genes coding enzymes engaged in amyloid precursor protein (APP) metabolism. It activates gene coding of α secretase, which is responsible for non-amyloidogenic pathway of APP degradation. It also down regulates β secretase (BACE-1), the main enzyme responsible for amyloid beta (Aβ) peptide release in Alzheimer Diseases (AD). In AD brain expression of genes of PPAR-α and PPAR-γ coactivator-1 alpha (PGC-1α) is significantly decreased. PPARs are altered not only in AD but in other neurodegenerative/neurodevelopmental and psychiatric disorder. PPAR-α downregulation may decrease anti-oxidative and anti-inflammatory processes and could be responsible for the alteration of fatty acid transport, lipid metabolism and disturbances of mitochondria function in the brain of AD patients. Specific activators of PPAR-α may be important for improvement of brain cells metabolism and cognitive function in neurodegenerative and neurodevelopmental disorders.

Transcriptional re-programming in rat central nervous system two weeks after burn trauma: the impact of nephrilin treatment on the expression of oxidative stress-related genes

INTRODUCTION

Survivors of severe burns suffer lifetime neuroinflammatory consequences manifested by higher incidence of major depression and neurodegenerative disease. In a scald model, nephrilin peptide has previously been shown to protect rats from loss of lean body mass, kidney function and glycaemic control, complications that have also been shown to endure in burn patient populations. Nephrilin's mechanism of action has been suggested to involve protection from excessive oxidative stress.

METHODS

Using quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) amplification of transcripts in total RNA extracted from dorsal root ganglia of male rats 14 days after exposure to thermal insult, we query the relative levels of expression of 34 genes believed to be associated with oxidative stress biology in the central nervous system (CNS). We use these data to explore the central role of oxidative stress in astrogliosis, immunosuppression and mitochondrial homeostasis.

RESULTS AND DISCUSSION

Rats that received nephrilin treatment (4 mg/kg by subcutaneous bolus injection once daily for seven days after scald injury) showed significantly reduced elevations in gene expression of some key genes such as NOX2, GFAP, AQP4 and RAC1, but not of others such as NOX4, STEAP4, ARG1 and CCL2.

CONCLUSION

The implications of these data with reference to nephrilin's potential clinical utility for mitigating the enduring effects of burn trauma on the CNS are discussed. Nephrilin reduces the expression of some genes implicated in neurodegeneration after burn insult.

LAY SUMMARY

Nephrilin peptide is a novel treatment for short- and long-term systemic effects of burn trauma. This study measures the capability of nephrilin to address post-traumatic neurodegenerative disease by looking at the expression of genes in the central nervous system, in a rat scald model. Nephrilin appears to have beneficial effects by reducing the expression of some key genes known to be relevant in neurodegenerative processes, but not others.

Circular RNA circDLGAP4 exerts neuroprotective effects via modulating miR-134-5p/CREB pathway in Parkinson's disease

Parkinson's disease (PD) is a neurodegenerative disease which is characterized by the substantia nigra dopaminergic neurons denatured. Circular RNA (circRNA) DLGAP4 (circDLGAP4) was found to have neuroprotective effect. In this study, we aimed to investigate whether circDLGAP4 participates in the progression of PD. Here, our results showed that circDLGAP4 expression was decreased in MPTP-induced PD mouse model and MPP⁺-induced PD cell models. In vitro study revealed that circDLGAP4 could promote viability, reduce apoptosis, decrease mitochondrial damage, enhance autophagy and thereby attenuated the neurotoxic effects of MPP⁺ in SH-SY5Y and MN9D cells. Further research suggested that circDLGAP4 exerted its functions via regulating miR-134-5p. Moreover, we demonstrated that CREB was a target of miR-134-5p and CREB expression could be regulated by circDLGAP4/miR-134-5p axis. CircDLGAP4/miR-134-5p could also modulate the activation of CREB signaling and thereby influence the expression of CREB target genes including BDNF, Bcl-2 and PGC-1α in SH-SY5Y and MN9D cells. In all, our study identifies that circDLGAP4 exerts neuroprotective effects via modulating miR-134-5p/CREB pathway both in human and mouse.

Effects of thymosin β4 on neuronal apoptosis in a rat model of cerebral ischemia‑reperfusion injury

The aim of the present study was to investigate the protective effects of thymosin β4 (Tβ4) on neuronal apoptosis in rat middle cerebral artery occlusion ischemia/reperfusion (MCAO I/R) injury, and determine the mechanisms involved in this process. Forty-eight adult male Sprague-Dawley rats were randomly divided into three groups (n=16 per group): A sham control group, an ischemia/reperfusion group (I/R group), and a Tβ4 group. The focal cerebral I/R model was established by blocking the right MCA for 2 h, followed by reperfusion for 24 h. The Zea-Longa method was used to assess neurological deficits. Cerebral infarct volume was assessed using 2,3,5-triphenyltetrazolium chloride staining, and pathological changes were observed via hematoxylin and eosin staining. The terminal dexynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) assay was used to detect apoptosis. The expression of glucose-regulated protein 78 (GRP78), C/EBP homologous protein (CHOP), and caspase-12 (CASP12) protein was assessed using immunohistochemistry and western blotting 24 h after reperfusion. Infarct volume and neuronal damage in the I/R and Tβ4 groups were significantly greater than those observed in the sham group. The Zea-Longa score, neuronal apoptosis, and expression of GRP78, CHOP, and CASP12 in the I/R and Tβ4 groups were significantly higher than those reported in the sham group. However, the Longa score and neuronal apoptosis were lower in the Tβ4 group compared to the I/R group. The expression of GRP78 was significantly increased, whereas that of CHOP and CASP12 was significantly decreased in the Tβ4 group compared to the I/R group. The present data revealed that Tβ4 can inhibit neuronal apoptosis by upregulating GRP78 and downregulating CHOP and CASP12, thereby reducing cerebral I/R injury.