Dual Role of Autophagy in Diseases of the Central Nervous System

Hydroxychloroquine alleviates maternal separation-induced schizophrenia-like behaviors by preventing autophagic degradation of TRPV1

Previous studies have shown that schizophrenia is closely related to transient receptor potential vanilloid1 (TRPV1). It is reported that downregulation of TRPV1 occurs in animals undergoing maternal separation (MS) which can induce behaviors and pathology reminiscent of schizophrenia. In vitro, cortisol was found to degrade TRPV1 via autophagy induction. Hydroxychloroquine (HCQ), an autophagy inhibitor, is recognized as an effective treatment to lower the risk of central nervous system degenerative diseases. This study aimed to explore whether HCQ can alleviate schizophrenia-like behaviors by modulating TRPV1 in a MS induced schizophrenia model. HCQ was administered at a dose of 2 mg/kg to rats just before MS on postnatal day 9 (PND9). Behavioral tests and measurements of biological markers were undertaken on PND10 and in adulthood. Furthermore, autophagy and TRPV1 levels were detected in the HT22 cells model. The results showed that autophagy levels increased in the hippocampus and prefrontal cortex of PND10 in MS rats, accompanied by decreased TRPV1. MS rats in adulthood showed impaired autophagy function and neuronal apoptosis in the hippocampus and prefrontal cortex, accompanied by schizophrenia-like behaviors. Early treatment with HCQ reverses these changes in MS rats and alleviates behavioral abnormalities. Our findings in the HT22 cells model confirmed the link between TRPV1 and autophagy. In summary, our findings suggest that HCQ prevents TRPV1 degradation via autophagy, alleviating MS-induced neurobiological and behavioral alterations.

FHL2 deteriorates IL-1β induced inflammation, apoptosis, and extracellular matrix degradation in chondrocyte-like ATDC5 cells by mTOR and NF-ĸB pathways

BACKGROUND

The role of nuclear translocation in osteoarthritis (OA) pathogenesis has garnered increasing attention in recent years. Extensive research has demonstrated that FHL2 acts as a nuclear transmitter through interactions with other nuclear transcription factors. We aimed to investigate the role of FHL2 in an osteoarthritis cell model.

METHODS

OA cartilage model was established by chondrocyte-like ATDC5 cells induced by 1% insulin-transferrin-selenium and then treated with interleukin-1β (IL-1β, 10 ng/mL). Lentivirus transfection was employed to suppress the expression of FHL2. Immunofluorescence and flow cytometry were used to examine nuclear transcription and apoptosis, respectively. Western blotting was performed to analyze the expression of metabolism-related proteins, autophagy-related proteins, apoptosis-related proteins, as well as proteins associated with the NF-ĸB and mTOR pathways.

RESULTS

The elevated expression of FHL2 occurred in both the cytoplasm and the nucleus. Knockdown of FHL2 could inhibit IL-1β-induced phosphorylation of NF-ĸB p65 and stabilize the extracellular matrix (ECM) by decreasing MMP-3 and MMP-13 expression, to suppress COL II degradation in chondrocyte-like ATDC5 cells. Meanwhile, the knockdown of FHL2-activated autophagy in IL-1β-treated chondrocytes through mTOR signaling, characterized by an increased LC3-II/LC3-I ratio and Beclin-1. FHL2 downregulation inhibited IL-1β-induced apoptosis by suppressing BAX and Caspase-3 expression, while enhancing BCL-2 protein levels. This mechanism may involve AKT phosphorylation and decreased expression of p-NF-ĸB p65.

CONCLUSIONS

FHL2 knockdown activated autophagy while suppressing inflammation, apoptosis, and ECM degradation. The mechanism underlying these processes may involve the inhibition of the mTOR and NF-ĸB signaling pathways.

The Association Among Bipolar Disorder, Mitochondrial Dysfunction, and Reactive Oxygen Species

Mitochondria, often known as the cell's powerhouses, are primarily responsible for generating energy through aerobic oxidative phosphorylation. However, their functions extend far beyond just energy production. Mitochondria play crucial roles in maintaining calcium balance, regulating apoptosis (programmed cell death), supporting cellular signaling, influencing cell metabolism, and synthesizing reactive oxygen species (ROS). Recent research has highlighted a strong link between bipolar disorder (BD) and mitochondrial dysfunction. Mitochondrial dysfunction contributes to oxidative stress, particularly through the generation of ROS, which are implicated in the pathophysiology of BD. Oxidative stress arises when there is an imbalance between the production of ROS and the cell's ability to neutralize them. In neurons, excessive ROS can damage various cellular components, including proteins in neuronal membranes and intracellular enzymes. Such damage may interfere with neurotransmitter reuptake and the function of critical enzymes, potentially affecting brain regions involved in mood regulation and emotional control, which are key aspects of BD. In this review, we will explore how various types of mitochondrial dysfunction contribute to the production of ROS. These include disruptions in energy metabolism, impaired ROS management, and defects in mitochondrial quality control mechanisms such as mitophagy (the process by which damaged mitochondria are selectively degraded). We will also examine how abnormalities in calcium signaling, which is crucial for synaptic plasticity, can lead to mitochondrial dysfunction. Additionally, we will discuss the specific mitochondrial dysfunctions observed in BD, highlighting how these defects may contribute to the disorder's pathophysiology. Finally, we will identify potential therapeutic targets to improve mitochondrial function, which could pave the way for new treatments to manage or mitigate symptoms of BD.

Explore autophagy-related lncRNA-miRNA-mRNA ceRNA networks for diagnosis of early-onset schizophrenia through transcriptome analysis

Background

The severe functional impairment and poor prognosis of early-onset schizophrenia (EOS) create a great need to identify effective biomarkers for early diagnosis in young psychiatric patients. Current research indicates a potential link between loss of autophagy function and emotional and behavioral abnormalities in individuals with psychiatric disorders.

Materials and Methods

This study aimed to explore diagnostic autophagy-related endogenous competitive RNA (ceRNA) networks for EOS patients. The messenger RNAs (mRNAs) and long non-coding RNAs (lncRNAs) expression profiles were obtained from peripheral blood mononuclear cells of 18 EOS patients and 12 healthy controls (HC). A co-expression analysis was performed between 365 core lncRNAs and 55 differentially expressed autophagy-related genes (ARGs) to identify differentially expressed autophagy-related lncRNAs. Subsequently, five diagnostic autophagy-related lncRNAs were identified as candidate genes to construct a ceRNA regulatory network using least absolute shrinkage and selection operator (LASSO) Cox regression, and receiver operating characteristic (ROC) curve analysis was performed to evaluate their predictive accuracy. Then, putative interactions among lncRNA-microRNAs (miRNAs)-mRNA were determined based on the lncRNASNP2 and TarBase databases.

Results

Three lncRNAs, twenty miRNAs, and ten mRNAs were selected to construct an autophagy-associated ceRNA network associated with EOS occurrence. Through protein-protein interaction network analysis, five hub mRNAs were identified, which exhibited good predictive ability in distinguishing EOS patients from healthy individuals. ROC curve analysis demonstrated that integrating three diagnostic lncRNAs (RP1-135L22.1, RP5-884C9.2, RP11-390F4.3) along with five hub mRNAs (EIF4G1, AKT1, BAX, WIPI2, MAPT) appeared to yield better diagnostic accuracy compared to using either lncRNAs or mRNAs alone. Furthermore, all three diagnostic lncRNAs and five hub mRNAs were positively correlated with at least two types of immune infiltration.

Conclusion

Through transcriptome analysis, we searched for diagnostic autophagy-related ceRNA networks, which provided valuable candidates for the early diagnosis of EOS.

Combining Chemotherapy Agents and Autophagy Modulators for Enhanced Breast Cancer Cell Death

Purpose

Autophagy, governed by genes with dual roles in cell death and survival, plays a crucial role in cancer persistence. Arsenic trioxide (ATO), carboplatin (CP), and cyclophosphamide (CY) are used to treat various cancers. ATO impedes cell proliferation and triggers apoptosis in cancer cells. CP, a platinum-based drug, damages cancer cell DNA, while CY acts as an alkylating agent, disrupting cell proliferation. This study investigates the combined effects of ATO, CP, and CY on inducing apoptosis and modulating autophagy in triple-negative breast cancer (TNBC) cell lines, BT-20 and MDA-MB-231.

Methods

The cytotoxic effects of ATO, CP, and CY, alone and in combination, were evaluated using the MTT assay on BT-20 and MDA-MB-231 cells. Apoptosis and cell cycle progression were analyzed by annexin-V FITC/PI staining and flow cytometry. Gene expression of autophagy-and apoptosis-related markers, including Beclin 1, LC3, caspase 3, and BCL2, was quantified using RT-PCR. Data were analyzed using GraphPad Prism 4.0 with one-way ANOVA followed by Dunnett's test.

Results

The combination of ATO, CP, and CY significantly reduced cell viability and enhanced apoptosis, evidenced by increased caspase-3 activity and reduced BCL2 expression. Cell cycle arrest in the G1 phase was observed, alongside elevated autophagy markers Beclin 1 and LC3.

Conclusion

The combination of ATO, CP, and CY induces synergistic effects in promoting apoptosis and autophagy in TNBC cell lines. These findings suggest that this combination therapy could be a promising approach to enhancing treatment efficacy in aggressive breast cancers, offering new insights into potential therapeutic strategies.

Ischemic Stroke Induces ROS Accumulation, Maladaptive Mitophagy, and Neuronal Apoptosis in Minipigs

Reactive oxygen species (ROS)-induced adaptive/maladaptive mitophagy plays an essential role in the pathophysiology of acute ischemic stroke (AIS). However, most studies have been conducted using rodent models, which limits their clinical application. In this study, we aimed to develop porcine models of permanent stroke and observe the pathophysiological alterations caused by acute ischemic stroke, focusing on ROS-induced mitophagy. Miniature pigs were subjected to lateral frontotemporal electrocoagulation, which resulted in permanent middle cerebral artery occlusion. We investigated global brain damage and mechanisms of adaptive/maladaptive mitophagy caused by ROS and global brain inflammation after AIS. An early neuroinflammatory response was observed in the ipsilateral hemisphere. ROS levels were significantly elevated in the ipsilateral hemisphere and slightly elevated in the contralateral hemisphere. ROS accumulation may be attributed to the increased production and impaired elimination of ROS. In addition, mitophagy and apoptosis were detected in the ischemic core, which may be attributed to ROS accumulation. We propose "distinct-area targeting" interventions aimed at maladaptive mitophagy within the ischemic core of the infarct hemisphere, which may provide new therapeutic targets for the treatment of AIS.

Lipids associated with autophagy: mechanisms and therapeutic targets

Autophagy is a molecular process essential for maintaining cellular homeostasis, with its impairment or dysregulation linked to the progression of various diseases in mammals. Specific lipids, including phosphoinositides, sphingolipids, and oxysterols, play pivotal roles in inducing and regulating autophagy, highlighting their significance in this intricate process. This review focuses on the critical involvement of these lipids in autophagy and lipophagy, providing a comprehensive overview of the current understanding of their functions. Moreover, we delve into how abnormalities in autophagy, influenced by these lipids, contribute to the pathogenesis of various diseases. These include age-related conditions such as cardiovascular diseases, neurodegenerative disorders, type 2 diabetes, and certain cancers, as well as inflammatory and liver diseases, skeletal muscle pathologies and age-related macular degeneration (AMD). This review aims to highlight function of lipids and their potential as therapeutic targets in treating diverse human pathologies by elucidating the specific roles of phosphoinositides, sphingolipids, and oxysterols in autophagy.

The autophagy paradox: A new hypothesis in neurodegenerative disorders

A recent study showed that while autophagy is usually tied to protein and organelle turnover, it can also play dual roles in neurodegenerative diseases. Traditionally, autophagy was seen as protective since it removes damaged proteins and organelles. but new data suggests autophagy can sometimes promote neuron death. and This review tackles autophagy's seemingly contradictory effects in neurodegeneration, or the "autophagy paradox. " It offers a framework for understanding autophagy in neurodegenerative research and the cellular processes involved. In short, our data uncovers a harmful autophagy role in certain situations, conflicting the view that it's always beneficial. We describe the distinct, disease-specific autophagy pathways functioning in various neurodegenerative diseases. Part two concerns potential therapeutic implications of manipulating autophagy and current strategies targeting the autophagic system, suggesting interesting areas for future research into tailored modulators. This could eventually enable activating or controlling specific autophagy pathways and aid in developing more effective treatments. Researchers believe more molecular-level research is needed so patient-tailored autophagy-modulating therapeutics can be developed given this dilemma. Moreover, research must translate faster into effective neurodegenerative disease treatment options. This article aims to provide a wholly new perspective on autophagy's classically described role in these severe diseases, challenging current dogma and opening new therapeutic avenue options.

Autophagy-associated biomarkers ULK2, UVRAG, and miRNAs miR-21, miR-126, and miR-374: Prognostic significance in glioma patients

As the pioneering study from Pakistan, our research distinctly focuses on validating the roles of autophagy-associated genes and MicroRNAs (miRs) in the unique context of our population for glioma prognosis. The study delves into the nuanced interplay of autophagy within a miR-modulated environment, prompting an exploration of its potential impact on glioma development and survival. Employing real-time PCR (qPCR), we meticulously assessed the expression profiles of autophagy genes and miRs in glioma tissues, complemented by immunohistochemistry on Formalin-fixed paraffin-embedded tissues from the same patients. Our comprehensive statistical analyses, including the data normality hypothesis Shapiro-Wilk test, the Mann-Whitney U-test, Spearman correlation test, and Kaplan-Meier survival analysis, were tailored to unravel the intricate associations specific to low- and high-grade glioma within our population. Clinicopathological analysis revealed a predominance of male patients (66%) with a median age of 35 years. Glioblastoma (32%) and Astrocytoma (36%) were the most prevalent histopathological subtypes. Molecular analysis showed significant correlations between prognostic markers (Ki-67, IDH-1, p53) and clinicopathological factors, including age, histological type, radiotherapy, and chemotherapy. In high-grade glioma, increased expression of AKT and miR-21, coupled with reduced ULK2 and LC3 expression was distinctly observed. While correlation analysis identified a strong positive correlation between ULK2 and UVRAG, PTEN, miR-7, and miR-100 in low-grade glioma, unveiling distinctive molecular signatures unique to our study. Furthermore, a moderate positive correlation emerged between ULK2 and mTOR, miR-7, miR-30, miR-100, miR-204, and miR-374, also between miR-21 and miR-126. Similarly, a positive correlation appeared between ULK2 and AKT, LC3, PI3K, PTEN, ULK1, VPS34, mTOR, Beclin1, UVRAG, miR-7 and miR-374. AKT positively correlated with LC3, PI3K, PTEN, ULK1, VPS34, mTOR, Beclin1, UVRAG, miR-7, miR-30, miR-204, miR-374, miR-126 and miR-21 weakly correlated with AKT and miR-30 in high-grade glioma, providing further insights into the autophagy pathway within our population. The enrichment analysis for miR-21, miR-126, and miR-374 showed MAPK pathway as a common pathway along with Ras, PI3K, and mTOR pathway. The low ULK2, UVRAG, and miR-374 expression group exhibited significantly poor overall survival in glioma, while miR-21 over-expression indicated a poor prognosis in glioma patients, validating it in our population. This study provides comprehensive insights into the molecular landscape of gliomas, highlighting the dysregulation of autophagy genes ULK2, and UVRAG and the associated miR-21, miR-126 and miR-374 as potential prognostic biomarkers and emphasizing their unique significance in shaping survival outcomes in gliomas within the specific context of the Pakistani population.

Autophagy defects at weaning impair complement-dependent synaptic pruning and induce behavior deficits

Autophagy is crucial for synaptic plasticity and the architecture of dendritic spines. However, the role of autophagy in schizophrenia (SCZ) and the mechanisms through which it affects synaptic function remain unclear. In this study, we identified 995 single nucleotide polymorphisms (SNPs) across 19 autophagy-related genes that are associated with SCZ. Gene Set Enrichment Analysis (GSEA) of data from the Gene Expression Omnibus public database revealed defective autophagy in patients with SCZ. Using a maternal immune activation (MIA) rat model, we observed that autophagy was downregulated during the weaning period, and early-life activation of autophagy with rapamycin restored abnormal behaviors and electrophysiological deficits in adult rats. Additionally, inhibition of autophagy with 3-Methyladenine (3-MA) during the weaning period resulted in aberrant behaviors, abnormal electrophysiology, increased spine density, and reduced microglia-mediated synaptic pruning. Furthermore, 3-MA treatment significantly decreased the expression and synaptosomal content of complement, impaired the recognition of C3b and CR3, indicating that autophagy deficiency disrupts complement-mediated synaptic pruning. Our findings provide evidence for a significant association between SCZ and defective autophagy, highlighting a previously underappreciated role of autophagy in regulating the synaptic and behavioral deficits induced by MIA.

Genetic associations between ULK3 and epilepsy: a two-sample Mendelian randomization study

Background and objectives

Observational studies have suggested that a multitude of pathological processes and biomolecules are involved in the initiation and development of epilepsy, and ULK3 is linked to the nervous system. However, it remains uncertain whether this association between ULK3 and epilepsy is causal and the direction of any causal relationship. This study employs a two-sample Mendelian randomization (MR) method to investigate the relationship between ULK3 and the risk of epilepsy.

Methods

We analyzed genome-wide association study (GWAS) summary statistics for ULK3 (sample size = 3,301), focal epilepsy (sample size = 39,348), and generalized epilepsy (sample size = 33,446). Bidirectional MR analyses were conducted to explore these relationships. We selected a set of single nucleotide polymorphisms (SNPs) with an association threshold of less than 1 × 10-5 as instrumental variables for further analysis. Various MR methods, including Inverse Variance Weighted, Weighted Median, MR-Egger Regression, Simple Model, Weighted Model, and Robust Adjustment Profile Score were used. Sensitivity analyses were performed to ensure the robustness of the results.

Results

Our MR analyses revealed a causal relationship where an increased level of ULK3 was associated with a decreased risk of focal epilepsy (odds ratio = 0.92, 95% confidence interval: 0.86-1.00, p = 0.041). No significant heterogeneity (Q = 7.85, p = 0.165) or horizontal pleiotropy (Egger regression intercept = 0.0191, p = 0.415) was detected. However, in the reverse analysis, we found no significant causal effect of focal epilepsy on ULK3 (p > 0.05). Furthermore, no significant causation was identified between ULK3 and generalized epilepsy (p > 0.05).

Conclusion

This study suggests a causal relationship between ULK3 and the risk of focal epilepsy from a genetic perspective. Nevertheless, further investigation is needed to understand the role of ULK3 in epilepsy fully.

Propolis as an autophagy modulator in relation to its roles in redox balance and inflammation regulation

Autophagy is a degradation process that is evolutionarily conserved and is essential in maintaining cellular and physiological homeostasis through lysosomal removal and elimination of damaged peptides, proteins and cellular organelles. The dysregulation of autophagy is implicated in various diseases and disorders, including cancers, infection-related, and metabolic syndrome-related diseases. Propolis has been demonstrated in various studies including many human clinical trials to have antimicrobial, antioxidant, anti-inflammatory, immune-modulator, neuro-protective, and anti-cancer. Nevertheless, the autophagy modulation properties of propolis have not been extensively studied and explored. The role of propolis and its bioactive compounds in modulating cellular autophagy is possibly due to their dual role in redox balance and inflammation. The present review attempts to discuss the activities of propolis as an autophagy modulator in biological models in relation to various diseases/disorders which has implications in the development of propolis-based nutraceuticals, functional foods, and complementary therapies.

Exploring neuroadaptive cellular pathways in chronic morphine exposure: An in-vitro analysis of cabergoline and Mdivi-1 co-treatment effects on the autophagy-apoptosis axis

The complex impacts of prolonged morphine exposure continue to be a significant focus in the expanding area of addiction studies. This research investigates the effectiveness of a combined treatment using Cabergoline and Mdivi-1 to counteract the neuroadaptive changes caused by in vitro morphine treatment. The impact of Methadone, Cabergoline, and a combination of Cabergoline and Mdivi-1 on the cellular and molecular responses associated with Morphine-induced changes was studied in human Neuroblastoma (SK-N-MC) and Glioblastoma (U87-MG) cell lines that were exposed to prolong Morphine treatment. Cabergoline and Mdivi-1 combined treatment effectively influenced the molecular alterations associated with neuroadaptation in chronic morphine-exposed neural cells. This combination therapy normalized autophagy and reduced oxidative stress by enhancing total-antioxidant capacity, mitigating apoptosis, restoring BDNF expression, and balancing apoptotic elements. Our research outlines morphine's dual role in modulating mitochondrial dynamics via the dysregulation of the autophagy-apoptosis axis. This emphasizes the significant involvement of DRP1 activity in neurological adaptation processes, as well as disturbances in the dopaminergic pathway during in vitro chronic exposure to morphine in neural cells. This study proposes a novel approach by recommending the potential effectiveness of combining Cabergoline and Mdivi-1 to modulate the neuroadaptations caused by morphine. Additionally, we identified BDNF and PCNA in neural cells as potential neuroprotective markers for assessing the effectiveness of drugs against opioid toxicity, emphasizing the need for further validation. The study uncovers diverse effects observed in pretreated morphine glioblastoma cells under treatment with Cabergoline and methadone. This highlights the potential for new treatments in the DRD2 pathway and underscores the importance of investigating the interplay between autophagy and apoptosis to advance research in managing cancer-related pain. The study necessitates an in-depth investigation into the relationship between autophagy and apoptosis, with a specific emphasis on protein interactions and the dynamics of cell signaling.

New Advances in the Pharmacology and Toxicology of Lithium: A Neurobiologically Oriented Overview

Over the last six decades, lithium has been considered the gold standard treatment for the long-term management of bipolar disorder due to its efficacy in preventing both manic and depressive episodes as well as suicidal behaviors. Nevertheless, despite numerous observed effects on various cellular pathways and biologic systems, the precise mechanism through which lithium stabilizes mood remains elusive. Furthermore, there is recent support for the therapeutic potential of lithium in other brain diseases. This review offers a comprehensive examination of contemporary understanding and predominant theories concerning the diverse mechanisms underlying lithium's effects. These findings are based on investigations utilizing cellular and animal models of neurodegenerative and psychiatric disorders. Recent studies have provided additional support for the significance of glycogen synthase kinase-3 (GSK3) inhibition as a crucial mechanism. Furthermore, research has shed more light on the interconnections between GSK3-mediated neuroprotective, antioxidant, and neuroplasticity processes. Moreover, recent advancements in animal and human models have provided valuable insights into how lithium-induced modifications at the homeostatic synaptic plasticity level may play a pivotal role in its clinical effectiveness. We focused on findings from translational studies suggesting that lithium may interface with microRNA expression. Finally, we are exploring the repurposing potential of lithium beyond bipolar disorder. These recent findings on the therapeutic mechanisms of lithium have provided important clues toward developing predictive models of response to lithium treatment and identifying new biologic targets. SIGNIFICANCE STATEMENT: Lithium is the drug of choice for the treatment of bipolar disorder, but its mechanism of action in stabilizing mood remains elusive. This review presents the latest evidence on lithium's various mechanisms of action. Recent evidence has strengthened glycogen synthase kinase-3 (GSK3) inhibition, changes at the level of homeostatic synaptic plasticity, and regulation of microRNA expression as key mechanisms, providing an intriguing perspective that may help bridge the mechanistic gap between molecular functions and its clinical efficacy as a mood stabilizer.

Antioxidants activities of phytochemicals perspective modulation of autophagy and apoptosis to treating cancer

The study of chemicals extracted from natural sources should be encouraged due to the significant number of cancer deaths each year and the financial burden imposed by this disease on society. The causes of almost all cancers involve a combination of lifestyle, environmental factors, and genetic and inherited factors. Modern medicine researchers are increasingly interested in traditional phytochemicals as they hold potential for new bioactive compounds with medical applications. Recent publications have provided evidence of the antitumor properties of phytochemicals, a key component of traditional Chinese medicine, thereby opening new avenues for their use in modern medicine. Various studies have demonstrated a strong correlation between apoptosis and autophagy, two critical mechanisms involved in cancer formation and regulation, indicating diverse forms of crosstalk between them. Phytochemicals have the ability to activate both pro-apoptotic and pro-autophagic pathways. Therefore, understanding how phytochemicals influence the relationship between apoptosis and autophagy is crucial for developing a new cancer treatment strategy that targets these molecular mechanisms. This review aims to explore natural phytochemicals that have demonstrated anticancer effects, focusing on their role in regulating the crosstalk between apoptosis and autophagy, which contributes to uncontrolled tumor cell growth. Additionally, the review highlights the limitations and challenges of current research methodologies while suggesting potential avenues for future research in this field.

Autophagy in Its (Proper) Context: Molecular Basis, Biological Relevance, Pharmacological Modulation, and Lifestyle Medicine

Autophagy plays a critical role in maintaining cellular homeostasis and responding to various stress conditions by the degradation of intracellular components. In this narrative review, we provide a comprehensive overview of autophagy's cellular and molecular basis, biological significance, pharmacological modulation, and its relevance in lifestyle medicine. We delve into the intricate molecular mechanisms that govern autophagy, including macroautophagy, microautophagy and chaperone-mediated autophagy. Moreover, we highlight the biological significance of autophagy in aging, immunity, metabolism, apoptosis, tissue differentiation and systemic diseases, such as neurodegenerative or cardiovascular diseases and cancer. We also discuss the latest advancements in pharmacological modulation of autophagy and their potential implications in clinical settings. Finally, we explore the intimate connection between lifestyle factors and autophagy, emphasizing how nutrition, exercise, sleep patterns and environmental factors can significantly impact the autophagic process. The integration of lifestyle medicine into autophagy research opens new avenues for promoting health and longevity through personalized interventions.

Autophagy dysregulation via the USP20-ULK1 axis in the HERC2-related neurodevelopmental disorder

Sequence variants in the HERC2 gene are associated with a significant reduction in HERC2 protein levels and cause a neurodevelopmental disorder known as the HERC2-related disorder, which shares clinical features with Angelman syndrome, including global developmental delay, intellectual disability, autism, and movement disorders. Remarkably, the HERC2 gene is commonly deleted in individuals with Angelman syndrome, suggesting a potential contribution of HERC2 to the pathophysiology of this disease. Given the known critical role of autophagy in brain development and its implication in neurodevelopmental diseases, we undertook different experimental approaches to monitor autophagy in fibroblasts derived from individuals affected by the HERC2-related disorder. Our findings reveal alterations in the levels of the autophagy-related protein LC3. Furthermore, experiments with lysosomal inhibitors provide confirmation of an upregulation of the autophagy pathway in these patient-derived cells. Mechanistically, we corroborate an interaction between HERC2 and the deubiquitylating enzyme USP20; and demonstrate that HERC2 deficiency leads to increased USP20 protein levels. Notably, USP20 upregulation correlates with enhanced stability of the autophagy initiating kinase ULK1, highlighting the role of HERC2 as an autophagy regulator factor through the USP20-ULK1 axis. Moreover, we show that p38 acts as a modulator of this pathway, since p38 activation disrupts HERC2-USP20 interaction, leading to increased USP20 and LC3-II protein levels. Together, these findings uncover a previously unknown role for HERC2 in autophagy regulation and provide insights into the pathomolecular mechanisms underlying the HERC2-related disorder and Angelman syndrome.

Targeting ERS-mitophagy in hippocampal neurons to explore the improvement of memory by tea polyphenols in aged type 2 diabetic rats

Increasing evidence demonstrated that mitophagy and endoplasmic reticulum stress (ERS) was closely associated with memory decline in elderly type 2 diabetes mellitus (T2DM). Tea polyphenols (TP), an excellent natural antioxidant, has been reported to have neuroprotective properties in aging and diabetes, but the underlying mechanisms are still not fully understood. This study targets ERS-mitophagy in hippocampal neurons to investigate the improvement effect of memory in aged T2DM rats by TP. Rats were randomly divided into the control group, the aged group, the aged T2DM model group, the TP 75, 150, 300 mg/kg groups. TP 300 mg/kg ameliorated mitophagy by decreasing the levels of p-mTOR (S2448), P62 and HSP60 and increasing the levels of PINK1 and Parkin, the ratio of LC3Ⅱ/LC3Ⅰ, co-localization of LC3 and HSP60 and the number of autophagosomes and autolysosomes. TP 300 mg/kg attenuated ERS by downregulating the levels of p-PERK, p-eIF2α, ATF4, GRP78 and restoring the ER structure. To further verify epigallocatechin gallate (EGCG), which is the main active component of TP, enhanced mitophagy by inhibiting ERS, PC12 cells were pretreated with ERS activator tunicamycin (TM) or ERS inhibitor 4-phenylbutyric acid (4-PBA). The results showed that the improvement of mitophagy by EGCG was inhibited by TM and promoted by 4-PBA. Collectively, ERS-mitophagy in hippocampal neurons plays a key role in the improvement of memory by TP in aged T2DM rats. This study will provide a new perspective and strategy for the prevention of memory decline in elderly with T2DM.

The Multiple Roles of Autophagy in Neural Function and Diseases

Autophagy involves the sequestration and delivery of cytoplasmic materials to lysosomes, where proteins, lipids, and organelles are degraded and recycled. According to the way the cytoplasmic components are engulfed, autophagy can be divided into macroautophagy, microautophagy, and chaperone-mediated autophagy. Recently, many studies have found that autophagy plays an important role in neurological diseases, including Alzheimer's disease, Parkinson's disease, Huntington's disease, neuronal excitotoxicity, and cerebral ischemia. Autophagy maintains cell homeostasis in the nervous system via degradation of misfolded proteins, elimination of damaged organelles, and regulation of apoptosis and inflammation. AMPK-mTOR, Beclin 1, TP53, endoplasmic reticulum stress, and other signal pathways are involved in the regulation of autophagy and can be used as potential therapeutic targets for neurological diseases. Here, we discuss the role, functions, and signal pathways of autophagy in neurological diseases, which will shed light on the pathogenic mechanisms of neurological diseases and suggest novel targets for therapies.

Methyl vinyl ketone and its analogs covalently modify PI3K and alter physiological functions by inhibiting PI3K signaling

Reactive carbonyl species (RCS), which are abundant in the environment and are produced in vivo under stress, covalently bind to nucleophilic residues such as Cys in proteins. Disruption of protein function by RCS exposure is predicted to play a role in the development of various diseases such as cancer and metabolic disorders, but most studies on RCS have been limited to simple cytotoxicity validation, leaving their target proteins and resulting physiological changes unknown. In this study, we focused on methyl vinyl ketone (MVK), which is one of the main RCS found in cigarette smoke and exhaust gas. We found that MVK suppressed PI3K-Akt signaling, which regulates processes involved in cellular homeostasis, including cell proliferation, autophagy, and glucose metabolism. Interestingly, MVK inhibits the interaction between the epidermal growth factor receptor and PI3K. Cys656 in the SH2 domain of the PI3K p85 subunit, which is the covalently binding site of MVK, is important for this interaction. Suppression of PI3K-Akt signaling by MVK reversed epidermal growth factor-induced negative regulation of autophagy and attenuated glucose uptake. Furthermore, we analyzed the effects of the 23 RCS compounds with structures similar to MVK and showed that their analogs also suppressed PI3K-Akt signaling in a manner that correlated with their similarities to MVK. Our study demonstrates the mechanism of MVK and its analogs in suppressing PI3K-Akt signaling and modulating physiological functions, providing a model for future studies analyzing environmental reactive species.

Pharmacological induction of autophagy reduces inflammation in macrophages by degrading immunoproteasome subunits

Defective autophagy is linked to proinflammatory diseases. However, the mechanisms by which autophagy limits inflammation remain elusive. Here, we found that the pan-FGFR inhibitor LY2874455 efficiently activated autophagy and suppressed expression of proinflammatory factors in macrophages stimulated by lipopolysaccharide (LPS). Multiplex proteomic profiling identified the immunoproteasome, which is a specific isoform of the 20s constitutive proteasome, as a substrate that is degraded by selective autophagy. SQSTM1/p62 was found to be a selective autophagy-related receptor that mediated this degradation. Autophagy deficiency or p62 knockdown blocked the effects of LY2874455, leading to the accumulation of immunoproteasomes and increases in inflammatory reactions. Expression of proinflammatory factors in autophagy-deficient macrophages could be reversed by immunoproteasome inhibitors, confirming the pivotal role of immunoproteasome turnover in the autophagy-mediated suppression on the expression of proinflammatory factors. In mice, LY2874455 protected against LPS-induced acute lung injury and dextran sulfate sodium (DSS)-induced colitis and caused low levels of proinflammatory cytokines and immunoproteasomes. These findings suggested that selective autophagy of the immunoproteasome was a key regulator of signaling via the innate immune system.

Autophagy-related gene model as a novel risk factor for schizophrenia

Autophagy, a cellular process where cells degrade and recycle their own components, has garnered attention for its potential role in psychiatric disorders, including schizophrenia (SCZ). This study aimed to construct and validate a new autophagy-related gene (ARG) risk model for SCZ. First, we analyzed differential expressions in the GSE38484 training set, identifying 4,754 differentially expressed genes (DEGs) between SCZ and control groups. Using the Human Autophagy Database (HADb) database, we cataloged 232 ARGs and pinpointed 80 autophagy-related DEGs (AR-DEGs) after intersecting them with DEGs. Subsequent analyses, including metascape gene annotation, pathway and process enrichment, and protein-protein interaction enrichment, were performed on the 80 AR-DEGs to delve deeper into their biological roles and associated molecular pathways. From this, we identified 34 candidate risk AR-DEGs (RAR-DEGs) and honed this list to final RAR-DEGs via a constructed and optimized logistic regression model. These genes include VAMP7, PTEN, WIPI2, PARP1, DNAJB9, SH3GLB1, ATF4, EIF4G1, EGFR, CDKN1A, CFLAR, FAS, BCL2L1 and BNIP3. Using these findings, we crafted a nomogram to predict SCZ risk for individual samples. In summary, our study offers deeper insights into SCZ's molecular pathogenesis and paves the way for innovative approaches in risk prediction, gene-targeted diagnosis, and community-based SCZ treatments.

The PB1 and the ZZ domain of the autophagy receptor p62/SQSTM1 regulate the interaction of p62/SQSTM1 with the autophagosome protein LC3B

Autophagy is a highly conserved cellular process that allows degradation of large macromolecules. p62/SQSTM1 is a key adaptor protein that interacts both with material to be degraded and with LC3 at the autophagosome, enabling degradation of cargos such as protein aggregates, lipid droplets and damaged organelles by selective autophagy. Dysregulation of autophagy contributes to the pathogenesis of many diseases. In this study, we investigated if the interaction of p62/SQSTM1 with LC3B could be regulated. We purified full-length p62/SQSTM1 and established an in vitro assay that measures the interaction with LC3B. We used the assay to determine the role of the different domains of p62/SQSTM1 in the interaction with LC3B. We identified a mechanism of regulation of p62/SQSTM1 where the ZZ and the PB1 domains regulate the exposure of the LIR-sequence to enable or inhibit the interaction with LC3B. A mutation to mimic the phosphorylation of a site on the ZZ domain leads to increased interaction with LC3B. Also, a small compound that binds to the ZZ domain enhances interaction with LC3B. Dysregulation of these mechanisms in p62/SQSTM1 could have implications for diseases where autophagy is affected. In conclusion, our study highlights the regulated nature of p62/SQSTM1 and its ability to modulate the interaction with LC3B through a LIR-sequence Accessibility Mechanism (LAM). Furthermore, our findings suggest the potential for pharmacological modulation of the exposure of LIR, paving the way for future therapeutic strategies.

Hypoxia and interleukin-1-primed mesenchymal stem/stromal cells as novel therapy for stroke

Promising preclinical stroke research has not yielded meaningful and significant success in clinical trials. This lack of success has prompted the need for refinement of preclinical studies with the intent to optimize the chances of clinical success. Regenerative medicine, especially using mesenchymal stem/stromal cells (MSCs), has gained popularity in the last decade for treating many disorders, including central nervous system (CNS), such as stroke. In addition to less stringent ethical constraints, the ample availability of MSCs also makes them an attractive alternative to totipotent and other pluripotent stem cells. The ability of MSCs to differentiate into neurons and other brain parenchymal and immune cells makes them a promising therapy for stroke. However, these cells also have some drawbacks that, if not addressed, will render MSCs unfit for treating ischaemic stroke. In this review, we highlighted the molecular and cellular changes that occur following an ischaemic stroke (IS) incidence and discussed the physiological properties of MSCs suitable for tackling these changes. We also went further to discuss the major drawbacks of utilizing MSCs in IS and how adequate priming using both hypoxia and interleukin-1 can optimize the beneficial properties of MSCs while eliminating these drawbacks.

The Role of Resveratrol on Spinal Cord Injury: from Bench to Bedside

Spinal cord injury (SCI) is a severe and disabling injury of the central nervous system, with complex pathological mechanisms leading to sensory and motor dysfunction. Pathological processes, such as oxidative stress, inflammatory response, apoptosis, and glial scarring are important factors that aggravate SCI. Therefore, the inhibition of these pathological processes may contribute to the treatment of SCI. Currently, the pathogenesis of SCI remains under investigation as SCI treatment has not progressed considerably. Resveratrol, a natural polyphenol with anti-inflammatory and antioxidant properties, is considered a potential therapeutic drug for various diseases and plays a beneficial role in nerve damage. Preclinical studies have confirmed that signaling pathways are closely related to the pathological processes in SCI, and resveratrol is believed to exert therapeutic effects in SCI by activating the related signaling pathways. Based on current research on the pathways of resveratrol and its role in SCI, resveratrol may be a potentially effective treatment for SCI. This review summarizes the role of resveratrol in promoting the recovery of nerve function by regulating oxidative stress, inflammation, apoptosis, and glial scar formation in SCI through various mechanisms and pathways, as well as the deficiency of resveratrol in SCI research and the current and anticipated research trends of resveratrol. In addition, this review provides a background for further studies on the molecular mechanisms of SCI and the development of potential therapeutic agents. This information could also help clinicians understand the known mechanisms of action of resveratrol and provide better treatment options for patients with SCI.

Serum HMGB1 and Beclin 1 Levels in Patients with a Diagnosis of Schizophrenia

OBJECTIVE

It is known that inflammation plays a role in the etiopathogenesis of schizophrenia. In this study, we examined high mobility group box 1 protein (HMGB1) and Beclin 1 levels and their relationship with clinical variables in patients with schizophrenia.

METHOD

Forty-three patients with schizophrenia and 43 healthy controls were included in this study. The patients were administered sociodemographic data form, the Positive Negative Symptoms Assessment Scale (PANSS) and the Clinical Global Impressions (CGI) scale. After the scales were filled, venous blood samples were taken from both the patient and control groups to measure serum HMGB1 and Beclin 1 levels. Serum samples obtained at the end of centrifugation were measured by Enzyme-Linked ImmunoSorbent Assay (ELISA) method.

RESULTS

The mean serum HMGB1 levels were significantly increased and the mean serum Beclin 1 levels were significantly decreased in the schizophrenia group compared to the control group. In addition, a negative correlation was found between HMGB1 and Beclin 1 levels.

CONCLUSION

In conclusion, current research shows that HMGB1 is increased and Beclin 1 is decreased in patients with schizophrenia, and these findings may contribute to the role of autophagy in the pathogenesis of schizophrenia.

The Analgesia Effect of Aucubin on CFA-Induced Inflammatory Pain by Inhibiting Glial Cells Activation-Mediated Inflammatory Response via Activating Mitophagy

BACKGROUND

Inflammatory pain, characterized by sustained nociceptive hypersensitivity, represents one of the most prevalent conditions in both daily life and clinical settings. Aucubin, a natural plant iridoid glycoside, possesses potent biological effects, encompassing anti-inflammatory, antioxidant, and neuroprotective properties. However, its impact on inflammatory pain remains unclear. The aim of this study is to investigate the therapeutic effects and underlying mechanism of aucubin in addressing inflammatory pain induced by complete Freund's adjuvant (CFA).

METHODS

The CFA-induced inflammatory pain model was employed to assess whether aucubin exerts analgesic effects and its potential mechanisms. Behavioral tests evaluated mechanical and thermal hyperalgesia as well as anxiety-like behaviors in mice. The activation of spinal glial cells and the expression of pro-inflammatory cytokines were examined to evaluate neuroinflammation. Additionally, RNA sequencing was utilized for the identification of differentially expressed genes (DEGs). Molecular biology experiments were conducted to determine the levels of the PINK1 gene and autophagy-related genes, along with PINK1 distribution in neural cells. Furthermore, mitophagy induced by carbonyl cyanide m-chlorophenylhydrazone (CCCP) was employed to examine the roles of PINK1 and mitophagy in pain processing.

RESULTS

Aucubin significantly ameliorated pain and anxiety-like behaviors induced by CFA in mice and reduced spinal inflammation. RNA sequencing indicated PINK1 as a pivotal gene, and aucubin treatment led to a significant downregulation of PINK1 expression. Further GO and KEGG analyses suggested the involvement of mitochondrial function in the therapeutic regulation of aucubin. Western blotting revealed that aucubin markedly decreased PINK1, Parkin, and p62 levels while increasing LC3B expression. Immunofluorescence showed the predominant co-localization of PINK1 with neuronal cells. Moreover, CCCP-induced mitophagy alleviated mechanical and thermal hyperalgesia caused by CFA and reversed CFA-induced mitochondrial dysfunction.

CONCLUSIONS

In summary, our data suggest that aucubin effectively alleviates CFA-induced inflammatory pain, potentially through triggering the PINK1 pathway, promoting mitophagy, and suppressing inflammation. These results provide a novel theoretical foundation for addressing the treatment of inflammatory pain.

An Overview of Recent Advances in the Neuroprotective Potentials of Fisetin against Diverse Insults in Neurological Diseases and the Underlying Signaling Pathways

The nervous system plays a leading role in the regulation of physiological functions and activities in the body. However, a variety of diseases related to the nervous system have a serious impact on human health. It is increasingly clear that neurological diseases are multifactorial pathological processes involving multiple cellular systems, and the onset of these diseases usually involves a diverse array of molecular mechanisms. Unfortunately, no effective therapy exists to slow down the progression or prevent the development of diseases only through the regulation of a single factor. To this end, it is pivotal to seek an ideal therapeutic approach for challenging the complicated pathological process to achieve effective treatment. In recent years, fisetin, a kind of flavonoid widely existing in fruits, vegetables and other plants, has shown numerous interesting biological activities with clinical potentials including anti-inflammatory, antioxidant and neurotrophic effects. In addition, fisetin has been reported to have diverse pharmacological properties and neuroprotective potentials against various neurological diseases. The neuroprotective effects were ascribed to its unique biological properties and multiple clinical pharmacological activities associated with the treatment of different neurological disorders. In this review, we summarize recent research progress regarding the neuroprotective potential of fisetin and the underlying signaling pathways of the treatment of several neurological diseases.

Dissecting the multifaced function of transcription factor EB (TFEB) in human diseases: From molecular mechanism to pharmacological modulation

The transcription factor EB (TFEB) is a transcription factor of the MiT/TFE family that translocations from the cytoplasm to the nucleus in response to various stimuli, including lysosomal stress and nutrient starvation. By activating genes involved in lysosomal function, autophagy, and lipid metabolism, TFEB plays a crucial role in maintaining cellular homeostasis. Dysregulation of TFEB has been implicated in various diseases, including cancer, neurodegenerative diseases, metabolic diseases, cardiovascular diseases, infectious diseases, and inflammatory diseases. Therefore, modulating TFEB activity with agonists or inhibitors may have therapeutic potential. In this review, we reviewed the recently discovered regulatory mechanisms of TFEB and their impact on human diseases. Additionally, we also summarize the existing TFEB inhibitors and agonists (targeted and non-targeted) and discuss unresolved issues and future research directions in the field. In summary, this review sheds light on the crucial role of TFEB, which may pave the way for its translation from basic research to practical applications, bringing us closer to realizing the full potential of TFEB in various fields.

Autophagy may protect the brain against prolonged consequences of headache attacks: A narrative/hypothesis review

OBJECTIVE

To assess the potential of autophagy in migraine pathogenesis.

BACKGROUND

The interplay between neurons and microglial cells is important in migraine pathogenesis. Migraine-related effects, such as cortical spreading depolarization and release of calcitonin gene-related peptide, may initiate adenosine triphosphate (ATP)-mediating pro-nociceptive signaling in the meninges causing headaches. Such signaling may be induced by the interaction of ATP with purinergic receptor P2X 7 (P2X7R) on microglial cells leading to a Ca2+ -mediated pH increase in lysosomes and release of autolysosome-like vehicles from microglial cells indicating autophagy impairment.

METHODS

A search in PubMed was conducted with the use of the terms "migraine," "autophagy," "microglia," and "degradation" in different combinations.

RESULTS

Impaired autophagy in microglia may activate secretory autophagy and release of specific proteins, including brain-derived neurotrophic factor (BDNF), which can be also released through the pores induced by P2X7R activation in microglial cells. BDNF may be likewise released from microglial cells upon ATP- and Ca2+ -mediated activation of another purinergic receptor, P2X4R. BDNF released from microglia might induce autophagy in neurons to clear cellular debris produced by oxidative stress, which is induced in the brain as the response to migraine-related energy deficit. Therefore, migraine-related signaling may impair degradative autophagy, stimulate secretory autophagy in microglia, and degradative autophagy in neurons. These effects are mediated by purinergic receptors P2X4R and P2X7R, BDNF, ATP, and Ca2+ .

CONCLUSION

Different effects of migraine-related events on degradative autophagy in microglia and neurons may prevent prolonged changes in the brain related to headache attacks.

HSPB2 facilitates neural regeneration through autophagy for sensorimotor recovery after traumatic brain injury

Autophagy is a promising target for promoting neural regeneration, which is essential for sensorimotor recovery following traumatic brain injury (TBI). Whether neuronal heat shock protein B2 (HSPB2), a small molecular heat shock protein, reduces injury and promotes recovery following TBI remains unclear. In this study, we demonstrated that HSPB2 was significantly increased in the neurons of a TBI mouse model, patients, and primary neuron cultures subjected to oxygen/glucose deprivation and reperfusion treatment. Upon creating a tamoxifen-induced neuron-specific HSPB2 overexpression transgenic mouse model, we found that elevated HSPB2 levels promoted long-term sensorimotor recovery and alleviated tissue loss after TBI. We also demonstrated that HSPB2 enhanced white matter structural and functional integrity, promoted central nervous system (CNS) plasticity, and accelerated long-term neural remodeling. Moreover, we found that autophagy occurred around injured brain tissues in patients, and the pro-regenerative effects of HSPB2 relied on its autophagy-promoting function. Mechanistically, HSPB2 may regulate autophagy possibly by forming the HSPB2/BCL2-associated athanogene 3/sequestosome-1 complex to facilitate the clearance of erroneously accumulated proteins in the axons. Treatment with the autophagy inhibitor chloroquine during the acute stage or delayed induction of HSPB2 remarkably impeded HSPB2's long-term reparative function, indicating the importance of acute-stage autophagy in long-term neuro-regeneration. Our findings highlight the beneficial role of HSPB2 in neuro-regeneration and functional recovery following acute CNS injury, thereby emphasizing the therapeutic potential of autophagy regulation for enhancing neuro-regeneration.

Dimethyl fumarate ameliorates Parkinsonian pathology by modulating autophagy and apoptosis via Nrf2-TIGAR-LAMP2/Cathepsin D axis

Mounting evidence suggests a role for oxidative stress and accumulation of dysfunctional organelle and misfolded proteins in PD. Autophagosomes mediate the clearance of these cytoplasmic proteins via delivery to lysosomes to form autophagolysosomes, followed by degradation of the protein by lysosomal enzymes. In PD, autophagolysosome accumulation occurs initiating a plethora of events resulting in neuronal death by apoptosis. This study evaluated the effect of Dimethylfumarate (DMF), an Nrf2 activator in the rotenone-induced mouse PD model. In PD mice, there was decreased expression of LAMP2 and LC3, which resulted in inhibition of autophagic flux and increased expression of cathepsin D, which mediated apoptosis. The role of Nrf2 activation in alleviating oxidative stress is well known. Our study elucidated the novel mechanism underlying the neuroprotective effect of DMF. The loss of dopaminergic neurons induced by rotenone was lessened to a significant extent by pre-treatment with DMF. DMF promoted autophagosome formation and inhibited apoptosis by removing the inhibitory effect of p53 on TIGAR. TIGAR expression upregulated LAMP2 expression and downregulated Cathepsin D, promoting autophagy and inhibiting apoptosis. Thus, it was proved that DMF confers neuroprotection against rotenone-induced dopaminergic neurodegeneration and could be used as a potential therapeutic agent for PD and its progression.

Common Signaling Pathways Involved in Alzheimer's Disease and Stroke: Two Faces of the Same Coin

Alzheimer's disease (AD) and stroke are two interrelated neurodegenerative disorders which are the leading cause of death and affect the neurons in the brain and central nervous system. Although amyloid-β aggregation, tau hyperphosphorylation, and inflammation are the hallmarks of AD, the exact cause and origin of AD are still undefined. Recent enormous fundamental discoveries suggest that the amyloid hypothesis of AD has not been proven and anti-amyloid therapies that remove amyloid deposition have not yet slowed cognitive decline. However, stroke, mainly ischemic stroke (IS), is caused by an interruption in the cerebral blood flow. Significant features of both disorders are the disruption of neuronal circuitry at different levels of cellular signaling, leading to the death of neurons and glial cells in the brain. Therefore, it is necessary to find out the common molecular mechanisms of these two diseases to understand their etiological connections. Here, we summarized the most common signaling cascades including autotoxicity, ApoE4, insulin signaling, inflammation, mTOR-autophagy, notch signaling, and microbiota-gut-brain axis, present in both AD and IS. These targeted signaling pathways reveal a better understanding of AD and IS and could provide a distinguished platform to develop improved therapeutics for these diseases.

Role of Macroautophagy in Mammalian Male Reproductive Physiology

Physiologically, autophagy is an evolutionarily conserved and self-degradative process in cells. Autophagy carries out normal physiological roles throughout mammalian life. Accumulating evidence shows autophagy as a mechanism for cellular growth, development, differentiation, survival, and homeostasis. In male reproductive systems, normal spermatogenesis and steroidogenesis need a balance between degradation and energy supply to preserve cellular metabolic homeostasis. The main process of autophagy includes the formation and maturation of the phagophore, autophagosome, and autolysosome. Autophagy is controlled by a group of autophagy-related genes that form the core machinery of autophagy. Three types of autophagy mechanisms have been discovered in mammalian cells: macroautophagy, microautophagy, and chaperone-mediated autophagy. Autophagy is classified as non-selective or selective. Non-selective macroautophagy randomly engulfs the cytoplasmic components in autophagosomes that are degraded by lysosomal enzymes. While selective macroautophagy precisely identifies and degrades a specific element, current findings have shown the novel functional roles of autophagy in male reproduction. It has been recognized that dysfunction in the autophagy process can be associated with male infertility. Overall, this review provides an overview of the cellular and molecular basics of autophagy and summarizes the latest findings on the key role of autophagy in mammalian male reproductive physiology.

In vitro methods in autophagy research: Applications in neurodegenerative diseases and mood disorders

Background

Autophagy is a conserved physiological intracellular mechanism responsible for the degradation and recycling of cytoplasmic constituents (e.g., damaged organelles, and protein aggregates) to maintain cell homeostasis. Aberrant autophagy has been observed in neurodegenerative diseases, including Alzheimer's Disease (AD), Parkinson's Disease (PD), Amyotrophic Lateral Sclerosis (ALS), and Huntington's Disease (HD), and recently aberrant autophagy has been associated with mood disorders, such as depression. Several in vitro methods have been developed to study the complex and tightly regulated mechanisms of autophagy. In vitro methods applied to autophagy research are used to identify molecular key players involved in dysfunctional autophagy and to screen autophagy regulators with therapeutic applications in neurological diseases and mood disorders. Therefore, the aims of this narrative review are (1) to compile information on the cell-based methods used in autophagy research, (2) to discuss their application, and (3) to create a catalog of traditional and novel in vitro methods applied in neurodegenerative diseases and depression.

Methods

Pubmed and Google Scholar were used to retrieve relevant in vitro studies on autophagy mechanisms in neurological diseases and depression using a combination of search terms per mechanism and disease (e.g., "macroautophagy" and "Alzheimer's disease"). A total of 37 studies were included (14 in PD, 8 in AD, 5 in ALS, 5 in %, and 5 in depression).

Results

A repertoire of traditional and novel approaches and techniques was compiled and discussed. The methods used in autophagy research focused on the mechanisms of macroautophagy, microautophagy, and chaperone-mediated autophagy. The in vitro tools presented in this review can be applied to explore pathophysiological mechanisms at a molecular level and to screen for potential therapeutic agents and their mechanism of action, which can be of great importance to understanding disease biology and potential therapeutic options in the context of neurodegenerative disorders and depression.

Conclusion

This is the first review to compile, discuss, and provide a catalog of traditional and novel in vitro models applied to neurodegenerative disorders and depression.

Autophagy and neurodegeneration: Unraveling the role of C9ORF72 in the regulation of autophagy and its relationship to ALS-FTD pathology

The proper functioning of the cell clearance machinery is critical for neuronal health within the central nervous system (CNS). In normal physiological conditions, the cell clearance machinery is actively involved in the elimination of misfolded and toxic proteins throughout the lifetime of an organism. The highly conserved and regulated pathway of autophagy is one of the important processes involved in preventing and neutralizing pathogenic buildup of toxic proteins that could eventually lead to the development of neurodegenerative diseases (NDs) such as Alzheimer’s disease or Amyotrophic lateral sclerosis (ALS). The most common genetic cause of ALS and frontotemporal dementia (FTD) is a hexanucleotide expansion consisting of GGGGCC (G4C2) repeats in the chromosome 9 open reading frame 72 gene (C9ORF72). These abnormally expanded repeats have been implicated in leading to three main modes of disease pathology: loss of function of the C9ORF72 protein, the generation of RNA foci, and the production of dipeptide repeat proteins (DPRs). In this review, we discuss the normal physiological role of C9ORF72 in the autophagy-lysosome pathway (ALP), and present recent research deciphering how dysfunction of the ALP synergizes with C9ORF72 haploinsufficiency, which together with the gain of toxic mechanisms involving hexanucleotide repeat expansions and DPRs, drive the disease process. This review delves further into the interactions of C9ORF72 with RAB proteins involved in endosomal/lysosomal trafficking, and their role in regulating various steps in autophagy and lysosomal pathways. Lastly, the review aims to provide a framework for further investigations of neuronal autophagy in C9ORF72-linked ALS-FTD as well as other neurodegenerative diseases.

Lithium engages autophagy for neuroprotection and neuroplasticity: translational evidence for therapy

Here an overview is provided on therapeutic/neuroprotective effects of Lithium (Li⁺) in neurodegenerative and psychiatric disorders focusing on the conspicuous action of Li⁺ through autophagy. The effects on the autophagy machinery remain the key molecular mechanisms to explain the protective effects of Li⁺ for neurodegenerative diseases, offering potential therapeutic strategies for the treatment of neuropsychiatric disorders and emphasizes a crossroad linking autophagy, neurodegenerative disorders, and mood stabilization. Sensitization by psychostimulants points to several mechanisms involved in psychopathology, most also crucial in neurodegenerative disorders. Evidence shows the involvement of autophagy and metabotropic Glutamate receptors-5 (mGluR5) in neurodegeneration due to methamphetamine neurotoxicity as well as in neuroprotection, both in vitro and in vivo models. More recently, Li⁺ was shown to modulate autophagy through its action on mGluR5, thus pointing to an additional way of autophagy engagement by Li⁺ and to a substantial role of mGluR5 in neuroprotection related to neural e neuropsychiatry diseases. We propose Li⁺ engagement of autophagy through the canonical mechanisms of autophagy machinery and through the intermediary of mGluR5.

Depletion of the RNA-binding protein PURA triggers changes in posttranscriptional gene regulation and loss of P-bodies

The RNA-binding protein PURA has been implicated in the rare, monogenetic, neurodevelopmental disorder PURA Syndrome. PURA binds both DNA and RNA and has been associated with various cellular functions. Only little is known about its main cellular roles and the molecular pathways affected upon PURA depletion. Here, we show that PURA is predominantly located in the cytoplasm, where it binds to thousands of mRNAs. Many of these transcripts change abundance in response to PURA depletion. The encoded proteins suggest a role for PURA in immune responses, mitochondrial function, autophagy and processing (P)-body activity. Intriguingly, reduced PURA levels decrease the expression of the integral P-body components LSM14A and DDX6 and strongly affect P-body formation in human cells. Furthermore, PURA knockdown results in stabilization of P-body-enriched transcripts, whereas other mRNAs are not affected. Hence, reduced PURA levels, as reported in patients with PURA Syndrome, influence the formation and composition of this phase-separated RNA processing machinery. Our study proposes PURA Syndrome as a new model to study the tight connection between P-body-associated RNA regulation and neurodevelopmental disorders.

Manganese-induced neuronal apoptosis: new insights into the role of endoplasmic reticulum stress in regulating autophagy-related proteins

Manganese (Mn) is an essential trace element that participates in various physiological and pathological processes. However, epidemiological observations indicate that overexposure to Mn is strongly associated with neurodegenerative disorders and has been recognized as a potential risk factor of neuronal apoptosis. Many mechanisms are involved in the pathogenesis of Mn-induced neuronal apoptosis, such as reactive oxygen species generation, neuroinflammation reactions, protein accumulation, endoplasmic reticulum stress (ER stress), and autophagy, all of which collectively accelerate the process of nerve cell damage. As sophisticated cellular processes for maintaining intracellular homeostasis, ER-mediated unfolded protein response and autophagy both play bilateral roles including cell protection and cell injury under pathophysiological conditions, which might interact with each other. Although emerging evidence suggests that ER stress is involved in regulating the compensatory activation of autophagy to promote cell survival, the inherent relationship between ER stress and autophagy on Mn-induced neurotoxicity remains obscure. Here, our review focuses on discussing the existing mechanisms and connections between ER stress, autophagy, and apoptosis, which provide a new perspective on Mn-induced neuronal apoptosis, and the pathogenesis of neurodegenerative diseases.

CTB-targeted protocells enhance ability of lanthionine ketenamine analogs to induce autophagy in motor neuron-like cells

Impaired autophagy, a cellular digestion process that eliminates proteins and damaged organelles, has been implicated in neurodegenerative diseases, including motor neuron disorders. Motor neuron targeted upregulation of autophagy may serve as a promising therapeutic approach. Lanthionine ketenamine (LK), an amino acid metabolite found in mammalian brain tissue, activates autophagy in neuronal cell lines. We hypothesized that analogs of LK can be targeted to motor neurons using nanoparticles to improve autophagy flux. Using a mouse motor neuron-like hybrid cell line (NSC-34), we tested the effect of three different LK analogs on autophagy modulation, either alone or loaded in nanoparticles. For fluorescence visualization of autophagy flux, we used a mCherry-GFP-LC3 plasmid reporter. We also evaluated protein expression changes in LC3-II/LC3-I ratio obtained by western blot, as well as presence of autophagic vacuoles per cell obtained by electron microscopy. Delivering LK analogs with targeted nanoparticles significantly enhanced autophagy flux in differentiated motor neuron-like cells compared to LK analogs alone, suggesting the need of a delivery vehicle to enhance their efficacy. In conclusion, LK analogs loaded in nanoparticles targeting motor neurons constitute a promising treatment option to induce autophagy flux, which may serve to mitigate motor neuron degeneration/loss and preserve motor function in motor neuron disease.

Neuroplasticity to autophagy cross-talk in a therapeutic effect of physical exercises and irisin in ADHD

Adaptive neuroplasticity is a pivotal mechanism for healthy brain development and maintenance, as well as its restoration in disease- and age-associated decline. Management of mental disorders such as attention deficit hyperactivity disorder (ADHD) needs interventions stimulating adaptive neuroplasticity, beyond conventional psychopharmacological treatments. Physical exercises are proposed for the management of ADHD, and also depression and aging because of evoked brain neuroplasticity. Recent progress in understanding the mechanisms of muscle-brain cross-talk pinpoints the role of the myokine irisin in the mediation of pro-cognitive and antidepressant activity of physical exercises. In this review, we discuss how irisin, which is released in the periphery as well as derived from brain cells, may interact with the mechanisms of cellular autophagy to provide protein recycling and regulation of brain-derived neurotrophic factor (BDNF) signaling via glia-mediated control of BDNF maturation, and, therefore, support neuroplasticity. We propose that the neuroplasticity associated with physical exercises is mediated in part by irisin-triggered autophagy. Since the recent findings give objectives to consider autophagy-stimulating intervention as a prerequisite for successful therapy of psychiatric disorders, irisin appears as a prototypic molecule that can activate autophagy with therapeutic goals.

Does treatment with autophagy-enhancers and/or ROS-scavengers alleviate behavioral and neurochemical consequences of low-dose rotenone-induced mild mitochondrial dysfunction in mice?

Bipolar-disorder's pathophysiology and the mechanism by which medications exert their beneficial effect is yet unknown, but others' and our data implicate patients' brain mitochondrial-dysfunction and its amendment by mood-stabilizers. We recently designed a novel mouse bipolar-disorder-like model using chronic administration of a low-dose of the oxidative-phosphorylation complex I inhibitor, rotenone. Four and eight weeks rotenone treatment induced manic- and depressive-like behavior, respectively, accompanied by mood-related neurochemical changes. Here we aimed to investigate whether each of the autophagy-enhancers lithium (a mood-stabilizer), trehalose and resveratrol and/or each of the reactive oxygen species (ROS)-scavengers, resveratrol and N-acetylcystein and/or the combinations lithium+resveratrol or trehalose+N-acetylcystein, can ameliorate behavioral and neurochemical consequences of neuronal mild mitochondrial-dysfunction. We observed that lithium, trehalose and N-acetylcystein reversed rotenone-induced manic-like behavior as well as deviations in protein levels of mitochondrial complexes and the autophagy marker LC3-II. This raises the possibility that mild mitochondrial-dysfunction accompanied by impaired autophagy and a very mild increase in ROS levels are related to predisposition to manic-like behavior. On the other hand, although, as expected, most of the drugs tested eliminated the eight weeks rotenone-induced increase in protein levels of all hippocampal mitochondrial complexes, only lithium ubiquitously ameliorated the depressive-like behaviors. We cautiously deduce that aberrant autophagy and/or elevated ROS levels are not involved in predisposition to the depressive phase of bipolar-like behavior. Rather, that amending the depressive-like characteristics requires different mitochondria-related interventions. The latter might be antagonizing N-methyl-D-aspartate receptors (NMDARs), thus protecting from disruption of mitochondrial calcium homeostasis and its detrimental consequences. In conclusion, our findings suggest that by-and-large, among the autophagy-enhancers and ROS-scavengers tested, lithium is the most effective in counteracting rotenone-induced changes. Trehalose and N-acetylcystein may also be effective in attenuating manic-like behavior.

Age-related changes in tau and autophagy in human brain in the absence of neurodegeneration

Tau becomes abnormally hyper-phosphorylated and aggregated in tauopathies like Alzheimers disease (AD). As age is the greatest risk factor for developing AD, it is important to understand how tau protein itself, and the pathways implicated in its turnover, change during aging. We investigated age-related changes in total and phosphorylated tau in brain samples from two cohorts of cognitively normal individuals spanning 19-74 years, without overt neurodegeneration. One cohort utilised resected tissue and the other used post-mortem tissue. Total soluble tau levels declined with age in both cohorts. Phosphorylated tau was undetectable in the post-mortem tissue but was clearly evident in the resected tissue and did not undergo significant age-related change. To ascertain if the decline in soluble tau was correlated with age-related changes in autophagy, three markers of autophagy were tested but only two appeared to increase with age and the third was unchanged. This implies that in individuals who do not develop neurodegeneration, there is an age-related reduction in soluble tau which could potentially be due to age-related changes in autophagy. Thus, to explore how an age-related increase in autophagy might influence tau-mediated dysfunctions in vivo, autophagy was enhanced in a Drosophila model and all age-related tau phenotypes were significantly ameliorated. These data shed light on age-related physiological changes in proteins implicated in AD and highlights the need to study pathways that may be responsible for these changes. It also demonstrates the therapeutic potential of interventions that upregulate turnover of aggregate-prone proteins during aging.

Transcription factor EB as a key molecular factor in human health and its implication in diseases

Transcription factor EB, as a component of the microphthalmia family of transcription factors, has been demonstrated to be a key controller of autophagy-lysosomal biogenesis. Transcription factor EB is activated by stressors such as nutrition and deprivation of growth factors, hypoxia, lysosomal stress, and mitochondrial injury. To achieve the ultimate functional state, it is controlled in a variety of modes, such as in its rate of transcription, post-transcriptional control, and post-translational alterations. Due to its versatile role in numerous signaling pathways, including the Wnt, calcium, AKT, and mammalian target of rapamycin complex 1 signaling pathways, transcription factor EB-originally identified to be an oncogene-is now well acknowledged as a regulator of a wide range of physiological systems, including autophagy-lysosomal biogenesis, response to stress, metabolism, and energy homeostasis. The well-known and recently identified roles of transcription factor EB suggest that this protein might play a central role in signaling networks in a number of non-communicable illnesses, such as cancer, cardiovascular disorders, drug resistance mechanisms, immunological disease, and tissue growth. The important developments in transcription factor EB research since its first description are described in this review. This review helps to advance transcription factor EB from fundamental research into therapeutic and regenerative applications by shedding light on how important a role it plays in human health and disease at the molecular level.

Dietary Tyrosine Intake (FFQ) Is Associated with Locus Coeruleus, Attention and Grey Matter Maintenance: An MRI Structural Study on 398 Healthy Individuals of the Berlin Aging Study-II

BACKGROUND AND OBJECTIVE

It is documented that low protein and amino-acid dietary intake is related to poorer cognitive health and increased risk of dementia. Degradation of the neuromodulatory pathways, (comprising the cholinergic, dopaminergic, serotoninergic and noradrenergic systems) is observed in neurodegenerative diseases and impairs the proper biosynthesis of key neuromodulators from micro-nutrients and amino acids. How these micro-nutrients are linked to neuromodulatory pathways in healthy adults is less studied. The Locus Coeruleus-Noradrenergic System (LC-NA) is the earliest subcortical structure affected in Alzheimer's disease, showing marked neurodegeneration, but is also sensitive for age-related changes. The LC-NA system is critical for supporting attention and cognitive control, functions that are enhanced both by tyrosine administration and chronic tyrosine intake. The purpose of this study was to 1) investigate whether the dietary intake of tyrosine, the key precursor for noradrenaline (NA), is related to LC signal intensity 2) whether LC mediates the reported association between tyrosine intake and higher cognitive performance (measured with Trail Making Test - TMT), and 3) whether LC signal intensity relates to an objective measure of brain maintenance (BrainPAD).

METHODS

The analyses included 398 3T MRIs of healthy participants from the Berlin Aging Study II to investigate the relationship between LC signal intensity and habitual dietary tyrosine intake-daily average (HD-Tyr-IDA - measured with Food Frequency Questionnaire - FFQ). As a control procedure, the same analyses were repeated on other main seeds of the neuromodulators' subcortical system (Dorsal and Medial Raphe, Ventral Tegmental Area and Nucleus Basalis of Meynert). In the same way, the relationships between the five nuclei and BrainPAD were tested.

RESULTS

Results show that HD-Tyr-IDA is positively associated with LC signal intensity. Similarly, LC disproportionally relates to better brain maintenance (BrainPAD). Mediation analyses reveal that only LC, relative to the other nuclei tested, mediates the relationship between HD-Tyr-IDA I and performance in the TMT and between HD-Tyr-IDA and BrainPAD.

CONCLUSIONS

These findings provide the first evidence linking tyrosine intake with LC-NA system signal intensity and its correlation with neuropsychological performance. This study strengthens the role of diet for maintaining brain and cognitive health and supports the noradrenergic theory of cognitive reserve. Within this framework, adequate tyrosine intake might increase the resilience of LC-NA system functioning, by preventing degeneration and supporting noradrenergic metabolism required for LC function and neuropsychological performance.

cGAS-STING pathway aggravates early cerebral ischemia-reperfusion injury in mice by activating NCOA4-mediated ferritinophagy

Stroke patients are often complicated by cerebral ischemia-reperfusion injury (CIRI) after the restoration of cerebral perfusion, and how to prevent CIRI at an early stage has received close attention. The imbalance of iron metabolism is one of the essential factors in the aggravation of CIRI, and NCOA4-mediated ferritinophagy, as a critical pathway to regulate iron metabolism, is expected to be an effective intervention target. We established a mouse model of cerebral ischemia-reperfusion (CIR) with NCOA4 silencing. We found that activation of NCOA4-mediated ferritinophagy atthe early stage of CIR mediated the onset of oxidative stress and contributed to autophagy and apoptosis, and eventually resulted in increased brain injury. This suggests that NCOA4-mediated ferritinophagy plays a vital role in early CIR and can be an effective target to prevent and treat CIRI. We next explored the upstream regulatory targets of NCOA4-mediated ferritinophagy. The previous evidence for the cGAS-STING pathway's importance during CIR and its strong relationship with autophagy attracted our attention. To investigate whether the cGAS-STING pathway regulates NCOA4-mediated ferritinophagy, we further administered a cGAS inhibitor to mice with CIR and overexpressed NCOA4. Along with the inhibition of the cGAS-STING pathway, ferritinophagy, oxidative stress, autophagy, and apoptosis were inhibited, and CIRI was ameliorated, which was attenuated by NCOA4 overexpression. In conclusion, our results suggest that activation of the cGAS-STING pathway exacerbates CIRI at the early stage of CIR, which may be achieved by mediating NCOA4-mediated ferritinophagy.

Branched-chain amino acids (BCAA) administration increases autophagy and the autophagic pathway in brain tissue of rats submitted to a Maple Syrup Urine Disease (MSUD) protocol

Maple Syrup Urine Disease (MSUD) is an inborn error of metabolism (EIM) biochemically characterized by the tissue accumulation of branched-chain amino acids (BCAA) and their branched-chain alpha-keto acids. The mechanisms by which BCAA and their branched-chain alpha-keto acids lead to the neurological damage observed in MSUD are poorly understood. Mounting evidence has demonstrated that BCAA induce the overproduction of reactive oxygen species, which may modulate several important signaling pathways necessary for cellular homeostasis maintenance, such as autophagy. Taking this into account, we evaluated the effects of BCAA on the autophagic pathway in brain structures of rats submitted to the administration of these amino acids (animal model of MSUD). Our findings showed that BCAA significantly increased the levels of Beclin-1, ATG7, and ATG5 in the cerebral cortex of rats. In addition, BCAA augmented ATG12 levels in the striatum and ATG5 and LC3 I-II in the hippocampus. Therefore, our work demonstrates that the administration of BCAA increases autophagy and autophagic cell death, possibly mediated by the elevated levels of reactive species generated by BCAA.

Non-SUMOylated alternative spliced isoforms of alpha-synuclein are more aggregation-prone and toxic

The exon skipping of α-Synuclein (α-Syn), the main constituent of the abnormal protein aggregation in Lewy bodies of Parkinson's disease (PD), forms four isoforms. In contrast to the full length α-Syn (α-Syn 140), little is known about the splice isoforms' properties and functions. SUMOylation, a post-translational modification, regulates α-Syn function, aggregation, and degradation, but information about α-Syn isoforms and the effect of SUMOylation on them is unknown. Therefore, this study aims to characterize the SUMOylation of α-Syn isoforms and its impact on cell death and α-Syn aggregation. In a cellular model of PD induced by rotenone, cell toxicity, SUMOylation, and α-Syn aggregation with or without isoforms overexpression were evaluated. First, rotenone induced cell toxicity and α-Syn aggregation, with a significant reduction of SUMOylation and autophagy. Boosting SUMOylation prevented α-Syn aggregation, phosphorylation and recovery of autophagy. Moreover, α-Syn 140 and α-Syn 126 were SUMOylated while the other two isoforms, α-Syn 112 and 98 were not and their overexpression showed that were more toxic and induced more α-Syn aggregation. Rotenone increased their toxicity that was not affected by boosting SUMOylation. These results may indicate a role of SUMOylation in modulating α-Syn aggregation, inducing to understanding more about the behavior of α-Syn isoforms.

A Review on Autophagy in Orofacial Neuropathic Pain

Orofacial neuropathic pain indicates pain caused by a lesion or diseases of the somatosensory nervous system. It is challenging for the clinician to diagnose and manage orofacial neuropathic pain conditions due to the considerable variability between individual clinical presentations and a lack of understanding of the mechanisms underlying the etiology and pathogenesis. In the last few decades, researchers have developed diagnostic criteria, questionnaires, and clinical assessment methods for the diagnosis of orofacial neuropathic pain. Recently, researchers have observed the role of autophagy in neuronal dysfunction as well as in the modulation of neuropathic pain. On this basis, in the present review, we highlight the characteristics, classification, and clinical assessment of orofacial neuropathic pain. Additionally, we introduce autophagy and its potential role in the modulation of orofacial neuropathic pain, along with a brief overview of the pathogenesis, which in future may reveal new possible targets for treating this condition.