Autophagy in Alzheimer's disease and promising modulatory effects of herbal medicine

Therapeutic Potential of MCC950 in Restoring Autophagy and Cognitive Function in STZ-Induced Rat Model of Alzheimer's Disease

Alzheimer's disease (AD) is currently the seventh leading cause of death worldwide. In this study, we explored the critical role of autophagy in AD pathology using a streptozotocin (STZ)-induced AD model in Wistar rats. The experimental groups included sham, STZ-induced AD, and STZ + MCC950-treated animals. Our findings revealed that administering two doses of STZ (3 mg/kg) intracerebroventricular at the interval of 48 h (on days 0 and 2), triggered autophagy, as evidenced by elevated levels of autophagy markers such as LC3II, ULK1, Beclin1, Ambra1, Cathepsin B, and a reduction in p62 levels. Behavioral assessments, including the water maze and novel object recognition tests, confirmed cognitive deficits and memory impairment, while the open-field test indicated increased anxiety in STZ-induced AD rats. In particular, treating the STZ-induced AD group with MCC950 (50 mg/kg) decreased the overexpression of autophagy-related proteins, which was consistent with better behavioral outcomes and lower anxiety. Overall, this study highlights new insights into AD pathophysiology and suggests potential therapeutic avenues.

The Potential Role of Phytochemicals in Alzheimer's Disease

Alzheimer's disease (AD) is a neurodegenerative condition characterised by memory loss and cognitive disorders. The disease has been related to the presence of so-called senile plaques forming due to the buildup of amyloid β in the hippocampus. The AD therapies developed to date continue to prove insufficient, while long-term exposure to synthetic drugs tends to lead to serious side effects, which is why potential herbal treatments are generally preferable to conventional drug regimens and, as such, have been under considerable research scrutiny in recent years. There are a number of herbs, e.g., lavender Ginkgo biloba, that are already commonly employed in alleviating the symptoms of certain neurological disorders. In light of the above, the aim of the following paper is to discuss the importance of medicinal herbs, their neuroprotective properties, and their mechanisms of activity. The article presents a review of the identified therapeutic properties of phytomedicines that exhibit strong anti-Alzheimer's disease (AD) activity.

Ferroptosis: A new strategy for targeting Alzheimer's disease

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by a complex pathogenesis, which involves the formation of amyloid plaques and neurofibrillary tangles. Many recent studies have revealed a close association between ferroptosis and the pathogenesis of AD. Factors such as ferroptosis-associated iron overload, lipid peroxidation, disturbances in redox homeostasis, and accumulation of reactive oxygen species have been found to contribute to the pathological progression of AD. In this review, we explore the mechanisms underlying ferroptosis, describe the link between ferroptosis and AD, and examine the reported efficacy of ferroptosis inhibitors in treating AD. Finally, we discuss the potential challenges to ferroptosis inhibitors use in the clinic, enabling their faster use in clinical treatment.

AdipoRon promotes amyloid-β clearance through enhancing autophagy via nuclear GAPDH-induced sirtuin 1 activation in Alzheimer's disease

BACKGROUND AND PURPOSE

Amyloid-β (Aβ) peptide is one of the more important pathological markers in Alzheimer's disease (AD). The development of AD impairs autophagy, which results in an imbalanced clearance of Aβ. Our previous research demonstrated that AdipoRon, an agonist of adiponectin receptors, decreased the deposition of Aβ and enhanced cognitive function in AD. However, the exact mechanisms by which AdipoRon affects Aβ clearance remain unclear.

EXPERIMENTAL APPROACH

We studied how AdipoRon affects autophagy in HT22 cells and APP/PS1 transgenic mice. We also investigated the signalling pathway involved and used pharmacological inhibitors to examine the role of autophagy in this process.

KEY RESULTS

AdipoRon promotes Aβ clearance by activating neuronal autophagy in the APP/PS1 transgenic mice. Interestingly, we found that AdipoRon induces the nuclear translocation of GAPDH, where it interacts with the SIRT1/DBC1 complex. This interaction then leads to the release of DBC1 and the activation of SIRT1, which in turn activates autophagy. Importantly, we found that inhibiting either GAPDH or SIRT1 to suppress the activity of SIRT1 counteracts the elevated autophagy and decreased Aβ deposition caused by AdipoRon. This suggests that SIRT1 plays a critical role in the effect of AdipoRon on autophagic induction in AD.

CONCLUSION AND IMPLICATIONS

AdipoRon promotes the clearance of Aβ by enhancing autophagy through the AdipoR1/AMPK-dependent nuclear translocation of GAPDH and subsequent activation of SIRT1. This novel molecular pathway sheds light on the modulation of autophagy in AD and may lead to the development of new therapeutic strategies targeting this pathway.

Pongamol Alleviates Neuroinflammation and Promotes Autophagy in Alzheimer's Disease by Regulating the Akt/mTOR Signaling Pathway

Alzheimer's disease (AD), one of the neurodegenerative disorders, is highly correlated with the abnormal hyperphosphorylation of Tau and aggregation of β-amyloid (Aβ). Oxidative stress, neuroinflammation, and abnormal autophagy are key drivers of AD and how they contribute to neuropathology remains largely unknown. The flavonoid compound pongamol is reported to possess a variety of pharmacological activities, such as antioxidant, antibacterial, and anti-inflammatory. This study investigated the neuroprotective effect and its mechanisms of pongamol in lipopolysaccharide (LPS)-induced BV2 cells, d-galactose/sodium nitrite/aluminum chloride (d-gal/NaNO2/AlCl3)-induced AD mice, and Caenorhabditis elegans models. Our research revealed that pongamol reduced the release of inflammatory factors IL-1β, TNF-α, COX-2, and iNOS in LPS-induced BV2 cells. Pongamol also protected neurons and significantly restored memory function, inhibited Tau phosphorylation, downregulated Aβ aggregation, and increased oxidoreductase activity in the hippocampus of AD mice. In addition, pongamol reversed the nuclear transfer of NF-κB and increased the levels of Beclin 1 and LC3 II/LC3 I. Most importantly, the anti-inflammatory and promoter autophagy effects of pongamol may be related to the regulation of the Akt/mTOR signaling pathway. In summary, these results showed that pongamol has a potential neuroprotective effect, which greatly enriched the research on the pharmacological activity of pongamol for improving AD.

Simple model systems reveal conserved mechanisms of Alzheimer's disease and related tauopathies

The lack of effective therapies that slow the progression of Alzheimer's disease (AD) and related tauopathies highlights the need for a more comprehensive understanding of the fundamental cellular mechanisms underlying these diseases. Model organisms, including yeast, worms, and flies, provide simple systems with which to investigate the mechanisms of disease. The evolutionary conservation of cellular pathways regulating proteostasis and stress response in these organisms facilitates the study of genetic factors that contribute to, or protect against, neurodegeneration. Here, we review genetic modifiers of neurodegeneration and related cellular pathways identified in the budding yeast Saccharomyces cerevisiae, the nematode Caenorhabditis elegans, and the fruit fly Drosophila melanogaster, focusing on models of AD and related tauopathies. We further address the potential of simple model systems to better understand the fundamental mechanisms that lead to AD and other neurodegenerative disorders.

Detection of early proteomic alterations in 5xFAD Alzheimer's disease neonatal mouse model via MALDI-MSI

Alzheimer's disease (AD) is a debilitating neurodegenerative disorder, characterized by memory deficit and dementia. AD is considered a multifactorial disorder where multiple processes like amyloid-beta and tau accumulation, axonal degeneration, synaptic plasticity, and autophagic processes plays an important role. In this study, the spatial proteomic differences in the neonatal 5xFAD brain tissue were investigated using MALDI-MSI coupled to LC-MS/MS, and the statistically significantly altered proteins were associated with AD. Thirty-five differentially expressed proteins (DEPs) between the brain tissues of neonatal 5xFAD and their littermate mice were detected via MALDI-MSI technique. Among the 35 proteins identified, 26 of them were directly associated with AD. Our results indicated a remarkable resemblance in the protein expression profiles of neonatal 5xFAD brain when compared to AD patient specimens or AD mouse models. These findings showed that the molecular alterations in the AD brain existed even at birth and that some proteins are neurodegenerative presages in neonatal AD brain. HIGHLIGHTS: Spatial proteomic alterations in the 5xFAD mouse brain compared to the littermate. 26 out of 35 differentially expressed proteins associated with Alzheimer's disease (AD). Molecular alterations and neurodegenerative presages in neonatal AD brain. Alterations in the synaptic function an early and common neurobiological thread.

Paeoniflorin, ferulic acid, and atractylenolide III improved LPS-induced neuroinflammation of BV2 microglia cells by enhancing autophagy

Microglia hyperactivation is an important cause of neuroinflammation in Alzheimer's disease (AD). Paeoniflorin (PF), ferulic acid (FA), and atractylenolide III (ATL) are potent in anti-inflammation and neuroprotection. Multiple components can act on different targets simultaneously to exert synergistic therapeutic effects and exploring the synergistic potential between compounds is an important area of research. We investigated the effects of PF, FA, and ATL, alone or in combination, on LPS-induced neuroinflammation and autophagy in BV2 microglia cells. We found that PF, FA, and ATL, alone or in combination, significantly reduced the production of inflammatory factors such as IL-6, IL-1β, and TNF-α, especially in the PF + FA + ATL group, which performed the best. In addition, the combination of PF, FA, and ATL significantly increased the expression of autophagy-related proteins p-AMPK, p-ULK1, Beclin1, LC3, and TFEB and decreased the expression of p62. Moreover, the restoration of autophagic flux by the combination of PF, FA, and ATL was abrogated by the addition of the autophagy inhibitor Wortmannin. In conclusion, PF, FA, and ATL have a synergistic effect in reducing LPS-induced inflammatory factor release from BV2 microglia cells, and its protective effect may be through activation of the AMPK/ULK1/TFEB autophagic signaling pathway.

Role of microglia autophagy and mitophagy in age-related neurodegenerative diseases

Microglia, characterized by responding to damage, regulating the secretion of soluble inflammatory mediators, and engulfing specific segments in the central nervous system (CNS), function as key immune cells in the CNS. Emerging evidence suggests that microglia coordinate the inflammatory responses in CNS system and play a pivotal role in the pathogenesis of age-related neurodegenerative diseases (NDDs). Remarkably, microglia autophagy participates in the regulation of subcellular substances, which includes the degradation of misfolded proteins and other harmful constituents produced by neurons. Therefore, microglia autophagy regulates neuronal homeostasis maintenance and process of neuroinflammation. In this review, we aimed at highlighting the pivotal role of microglia autophagy in the pathogenesis of age-related NDDs. Besides the mechanistic process and the co-interaction between microglia autophagy and different kinds of NDDs, we also emphasized potential therapeutic agents and approaches that could be utilized at the onset and progression of these diseases through modulating microglia autophagy, including promising nanomedicines. Our review provides a valuable reference for subsequent studies focusing on treatments of neurodegenerative disorders. The exploration of microglia autophagy and the development of nanomedicines greatly enhances current understanding of NDDs.

Mechanisms of manganese-induced neurotoxicity and the pursuit of neurotherapeutic strategies

Chronic exposure to elevated levels of manganese via occupational or environmental settings causes a neurological disorder known as manganism, resembling the symptoms of Parkinson's disease, such as motor deficits and cognitive impairment. Numerous studies have been conducted to characterize manganese's neurotoxicity mechanisms in search of effective therapeutics, including natural and synthetic compounds to treat manganese toxicity. Several potential molecular targets of manganese toxicity at the epigenetic and transcriptional levels have been identified recently, which may contribute to develop more precise and effective gene therapies. This review updates findings on manganese-induced neurotoxicity mechanisms on intracellular insults such as oxidative stress, inflammation, excitotoxicity, and mitophagy, as well as transcriptional dysregulations involving Yin Yang 1, RE1-silencing transcription factor, transcription factor EB, and nuclear factor erythroid 2-related factor 2 that could be targets of manganese neurotoxicity therapies. This review also features intracellular proteins such as PTEN-inducible kinase 1, parkin, sirtuins, leucine-rich repeat kinase 2, and α-synuclein, which are associated with manganese-induced dysregulation of autophagy/mitophagy. In addition, newer therapeutic approaches to treat manganese's neurotoxicity including natural and synthetic compounds modulating excitotoxicity, autophagy, and mitophagy, were reviewed. Taken together, in-depth mechanistic knowledge accompanied by advances in gene and drug delivery strategies will make significant progress in the development of reliable therapeutic interventions against manganese-induced neurotoxicity.

Analysis of the Effects of Curculin on Neuronal Cells, Glutamate Transporter Solute Carrier Family 1, Learning and Memory in Alzheimer’s Disease Rats

Our study assessed curculin’s effects on neurons, GLT-1, and behavioral learning ability of AD rats. 40 rats were divided randomly into low curculoside group (CAS1 group), high curculoside group (CAS2 group), normal group (WG group) and model group (GS group) (stereotactic injection of Aβ into hippocampus) followed by analysis of learning ability by Y-maze, GLT-1 level by immunofluorescence histochemistry, neuron morphology by HE staining, GLU content by HPLC, GLT-1 level by western blot, and apoptosis by TUNEL assay. Compared with WG group, GS group had significantly elevated number of exercises and wrong actions, total reaction time and Glu content (20.52±2.09 μmol/L versus 7.51±1.21 μmol/L) and reduced GLT-1 level (0.47±0.06 versus 1.23±0.07) (P < 0.01). In addition, increased apoptosis rate was found in GS group (69.78±9.97) compared to WG group (8.42±2.13) (P < 0.01). Compared with GS group, CAS1 and CAS2 groups had improved changes (P < 0.01) with more improvement in CAS2 group than CAS1 group. In conclusion, curculoside can inhibit GLU expression, reduce neuronal cell apoptosis, and improve the learning ability of AD rats, which may be related to the inhibition of GLT-1 in AD rats.

Chinese Herbal Medicine Adjusting Brain Microenvironment via Mediating Central Nervous System Lymphatic Drainage in Alzheimer's Disease

Due to its complex pathogenesis and lack of effective therapeutic methods, Alzheimer's disease (AD) has become a severe public health problem worldwide. Recent studies have discovered the function of central nervous system lymphatic drainage, which provides a new strategy for the treatment of AD. Chinese herbal medicine (CHM) has been considered as a cure for AD for hundreds of years in China, and its effect on scavenging β-amyloid protein in the brain of AD patients has been confirmed. In this review, the mechanism of central nervous system lymphatic drainage and the regulatory functions of CHM on correlation factors were briefly summarized. The advances in our understanding regarding the treatment of AD via regulating the central lymphatic system with CHM will promote the clinical application of CHM in AD patients and the discovery of new therapeutic drugs.

Protein degradation-associated mechanisms that are affected in Alzheimer´s disease

Alzheimer's disease (AD) is the most common type of dementia associated with age-related neurodegeneration. Alteration of several molecular mechanisms has been correlated with the progression of AD. In recent years, dysregulation of proteostasis-associated pathways has emerged as a potential risk factor for neurodegenerative diseases. This review investigated the ubiquitin-proteasome system, lysosome-associated degradation, endoplasmic-reticulum-associated degradation, and the formation of advanced glycation end products. These pathways involved in proteostasis have been reported to be altered in AD, suggesting that their study may be critical for identifying new biomarkers and target molecules for AD.

Exploring the Mechanism of Panax notoginseng Saponins against Alzheimer's Disease by Network Pharmacology and Experimental Validation

Background

Panax notoginseng saponins (PNS) have been used for neurodegenerative disorders such as cerebral ischemia and Alzheimer's disease (AD). Although increasing evidences show the neuron protective effects of PNS, the vital compounds and their functional targets remain elusive. To explore the potential functional ingredients of PNS for the AD treatment and their molecular mechanisms, an in vitro neuron injured model induced by Aβ was investigated, and the potential mechanism was predicted by network pharmacology approach and validated by molecular biology methods.

Methods

Network pharmacology approach was used to reveal the relationship between ingredient-target disease and function-pathway of PNS on the treatment of AD. The active ingredients of PNS were collected from TCMSP, PubChem database, and literature mining in PubMed database. DrugBank and GeneCards database were used to predict potential targets for AD. The STRING database was performed to reveal enrichment of these target proteins, protein-protein interactions, and related pathways. Networks were visualized by utilizing Cytoscape software. The enrichment analysis was performed by the DAVID database. Finally, neuroprotective effect and predictive mechanism of PNS were investigated in an in vitro AD model established by Aβ_25–35-treated PC12 cells.

Results

An ingredient-target disease and function-pathway network demonstrated that 38 active ingredients were derived from PNS modulated 364 common targets shared by PNS and AD. GO and KEGG analysis, further clustering analysis, showed that mTOR signaling targets were associated with the neuroprotective effects of PNS. In Aβ-treated PC12 cells, PNS treatment improved neuroprotective effect, including mTOR inhibition and autophagy activation.

Conclusions

Collectively, the protective effects of PNS on AD-neuron injury are related to the inhibition of mTOR and autophagy activation.

Targeting autophagy in ethnomedicine against human diseases

ETHNOPHARMACOLOGICAL RELEVANCE

In the past five years, ethnopharmacy-based drugs have been increasingly used in clinical practice. It has been reported that hundreds of ethnopharmacy-based drugs can modulate autophagy to regulate physiological and pathological processes, and ethnomedicines also have certain therapeutic effects on illnesses, revealing the important roles of these medicines in regulating autophagy and treating diseases.

AIM OF THE STUDY

This study reviews the regulatory effects of natural products on autophagy in recent years, and discusses their pharmacological effects and clinical applications in the process of diseases. It provides a preliminary literature basis and reference for the research of plant drugs in the regulation of autophagy.

MATERIALS AND METHODS

A comprehensive systematic review in the fields of relationship between autophagy and ethnomedicine in treating diseases from PubMed electronic database was performed. Information was obtained from documentary sources.

RESULTS

We recorded some illnesses associated with autophagy, then classified them into different categories reasonably. Based on the uses of these substances in different researches of diseases, a total of 80 active ingredients or compound preparations of natural drugs were searched. The autophagy mechanisms of these substances in the treatments of divers diseases have been summarized for the first time, we also looked forward to the clinical application of some of them.

CONCLUSIONS

Autophagy plays a key function in lots of illnesses, the regulation of autophagy has become one of the important means to prevent and treat these diseases. About 80 compounds and preparations involved in this review have been proved to have therapeutic effects on related diseases through the mechanism of autophagy. Experiments in vivo and in vitro showed that these compounds and preparations could treat these diseases by regulating autophagy. The typical natural products curcumin and tripterine have powerful roles in regulating autophagy and show good and diversified curative effects.

Impacts of oxidants and antioxidants on the emergence and progression of Alzheimer's disease

The brain shows a high sensitivity to oxidative stress (OS). Thus, the maintenance of homeostasis of the brain regarding the reduction-oxidation (redox) situation is crucial for the regular function of the central nervous systems (CNS). The imbalance between the reactive oxygen species (ROS) and the cellular mechanism might lead to the emergence of OS, causing profound cell death as well as tissue damages and initiating neurodegenerative disorders (NDDs). Characterized by the cytoplasmic growth of neurofibrillary tangles and extracellular β-amyloid plaques, Alzheimer's disease (AD) is a complex NDD that causes dementia in adult life with severe manifestations. Nuclear factor erythroid 2-related factor 2 (NRF2) is a key transcription factor that regulates the functional expression of OS-related genes and the functionality of endogenous antioxidants. In the case of oxidative damage, NRF2 is transferred to the nucleus and attached to the antioxidant response element (ARE) that enhances the sequence to initiate transcription of the cell-protecting genes. This review articulates various mechanisms engaged with the generation of active and reactive species of endogenous and exogenous oxidants and focuses on the antioxidants as a body defense system regarding the NRF2-ARE signaling path in the CNS.

The N-Formyl Peptide Receptor 2 (FPR2) Agonist MR-39 Improves Ex Vivo and In Vivo Amyloid Beta (1-42)-Induced Neuroinflammation in Mouse Models of Alzheimer's Disease

The major histopathological hallmarks of Alzheimer's disease (AD) include β-amyloid (Aβ) plaques, neurofibrillary tangles, and neuronal loss. Aβ 1-42 (Aβ1-42) has been shown to induce neurotoxicity and secretion of proinflammatory mediators that potentiate neurotoxicity. Proinflammatory and neurotoxic activities of Aβ1-42 were shown to be mediated by interactions with several cell surface receptors, including the chemotactic G protein-coupled N-formyl peptide receptor 2 (FPR2). The present study investigated the impact of a new FPR2 agonist, MR-39, on the neuroinflammatory response in ex vivo and in vivo models of AD. To address this question, organotypic hippocampal cultures from wild-type (WT) and FPR2-deficient mice (knockout, KO, FPR2-/-) were treated with fibrillary Aβ1-42, and the effect of the new FPR2 agonist MR-39 on the release of pro- and anti-inflammatory cytokines was assessed. Similarly, APP/PS1 double-transgenic AD mice were treated for 20 weeks with MR-39, and immunohistological staining was performed to assess neuronal loss, gliosis, and Aβ load in the hippocampus and cortex. The data indicated that MR-39 was able to reduce the Aβ1-42-induced release of proinflammatory cytokines and to improve the release of anti-inflammatory cytokines in mouse hippocampal organotypic cultures. The observed effect was apparently related to the inhibition of the MyD88/TRAF6/NFкB signaling pathway and a decrease in NLRP3 inflammasome activation. Administration of MR-39 to APP/PS1 mice improved neuronal survival and decreased microglial cell density and plaque load.These results suggest that FPR2 may be a promising target for alleviating the inflammatory process associated with AD and that MR-39 may be a useful therapeutic agent for AD.

A multitude of signaling pathways associated with Alzheimer's disease and their roles in AD pathogenesis and therapy

The exact molecular mechanisms associated with Alzheimer's disease (AD) pathology continue to represent a mystery. In the past decades, comprehensive data were generated on the involvement of different signaling pathways in the AD pathogenesis. However, the utilization of signaling pathways as potential targets for the development of drugs against AD is rather limited due to the immense complexity of the brain and intricate molecular links between these pathways. Therefore, finding a correlation and cross-talk between these signaling pathways and establishing different therapeutic targets within and between those pathways are needed for better understanding of the biological events responsible for the AD-related neurodegeneration. For example, autophagy is a conservative cellular process that shows link with many other AD-related pathways and is crucial for maintenance of the correct cellular balance by degrading AD-associated pathogenic proteins. Considering the central role of autophagy in AD and its interplay with many other pathways, the finest therapeutic strategy to fight against AD is the use of autophagy as a target. As an essential step in this direction, this comprehensive review represents recent findings on the individual AD-related signaling pathways, describes key features of these pathways and their cross-talk with autophagy, represents current drug development, and introduces some of the multitarget beneficial approaches and strategies for the therapeutic intervention of AD.

High-throughput virtual screening and microsecond MD simulations to identify potential sugar mimic of the solute-binding protein BlAXBP of the ABC transporter from Bifidobacterium animalis subsp. Lactis

Xylotetraose is a prebiotic oligosaccharide can be utilized by the ABC transporter of the gut microbiota Bifidobacteria. BlAXBP is the solute binding protein of the ABC transporter, and its complex with xylotetraose has been solved by X-ray crystallography. Here, we have identified novel sugar mimic of BlAXBP by applying a high-throughput virtual screening of ZINC database containing a huge library with ∼22 M compounds. To begin with, we identified 18,571 ligands by a ligand-based virtual screening. Further, a total of 3968 compounds were selected for molecular docking due to their Tanimoto coefficient's value were larger than a cutoff of 0.08. The molecular mechanics-generalized born surface area was used to evaluate the binding free energies, and the top 10 ligands with free energies below an energy threshold of -35.22 kcal/mol were selected. ZINC13783511 formed the most stable complex with BlAXBP and its recognition mechanism were further explored by microsecond MD simulations in explicit solvent. Free energy landscapes were used to evaluate conformational changes of BlAXBP in its ligand free and binding states. Collectively, this work identified potential novel sugar mimics to BlAXBP, providing novel atomic-level understanding of the binding mechanism.

Role of amber extract in protecting SHSY5Y cells against amyloid β1-42-induced neurotoxicity

Alzheimer disease (AD) is an irreversible, progressive brain disease. Amyloid β plays a critical role in AD development. Some Chinese traditional medicines, such as the fossilized plant resin, amber, have been applied as mental stabilizers. However, the effects of amber on AD pathogenesis remain unknown. Therefore, we aimed to determine the potential of amber extract for treating AD by evaluating its effects on amyloid-β (1-42) (Aβ (1-42))-induced neuronal cell death. We measured levels of ROS, Bcl-2, and Bax mRNA, and found that amber extract decreased Aβ (1-42)-induced cell apoptosis via the reactive oxygen species (ROS)-mediated mitochondrial pathway. Amber extract also decreased β-site amyloid precursor protein cleaving enzyme 1 (BACE1) and increased microtubule-associated proteins 1A/1B light chain 3B (LC3II) and Beclin 1. These findings suggested that amber extract protects neuronal cells against Aβ (1-42)-induced cell apoptosis by upregulating autophagy and downregulating BACE1.

Current Quest in Natural Bioactive Compounds for Alzheimer's Disease: Multi-Targeted-Designed-Ligand Based Approach with Preclinical and Clinical Based Evidence

Alzheimer's disease is a common and most chronic neurological disorder (NDs) associated with cognitive dysfunction. Pathologically, Alzheimer's disease (AD) is characterized by the presence of β-amyloid (Aβ) plaques, hyper-phosphorylated tau proteins, and neurofibrillary tangles, however, persistence oxidative-nitrative stress, endoplasmic reticulum stress, mitochondrial dysfunction, inflammatory cytokines, pro-apoptotic proteins along with altered neurotransmitters level are common etiological attributes in its pathogenesis. Rivastigmine, memantine, galantamine, and donepezil are FDA approved drugs for symptomatic management of AD, whereas tacrine has been withdrawn because of hepatotoxic profile. These approved drugs only exert symptomatic relief and exhibit poor patient compliance. In the current scenario, the number of published evidence shows the neuroprotective potential of naturally occurring bioactive molecules via their antioxidant, anti-inflammatory, antiapoptotic and neurotransmitter modulatory properties. Despite their potent therapeutic implications, concerns have arisen in context to their efficacy and probable clinical outcome. Thus, to overcome these glitches, many heterocyclic and cyclic hydrocarbon compounds inspired by natural sources have been synthesized and showed improved therapeutic activity. Computational studies (molecular docking) have been used to predict the binding affinity of these natural bioactive as well as synthetic compounds derived from natural sources for the acetylcholine esterase, α/β secretase Nuclear Factor kappa- light-chain-enhancer of activated B cells (NF-kB), Nuclear factor erythroid 2-related factor 2(Nrf2) and other neurological targets. Thus, in this review, we have discussed the molecular etiology of AD, focused on the pharmacotherapeutics of natural products, chemical and pharmacological aspects and multi-targeted designed ligands (MTDLs) of synthetic and semisynthetic molecules derived from the natural sources along with some important on-going clinical trials.

Alzheimer's Disease Pathogenesis: Role of Autophagy and Mitophagy Focusing in Microglia

Alzheimer's disease (AD) is a debilitating neurological disorder, and currently, there is no cure for it. Several pathologic alterations have been described in the brain of AD patients, but the ultimate causative mechanisms of AD are still elusive. The classic hallmarks of AD, including amyloid plaques (Aβ) and tau tangles (tau), are the most studied features of AD. Unfortunately, all the efforts targeting these pathologies have failed to show the desired efficacy in AD patients so far. Neuroinflammation and impaired autophagy are two other main known pathologies in AD. It has been reported that these pathologies exist in AD brain long before the emergence of any clinical manifestation of AD. Microglia are the main inflammatory cells in the brain and are considered by many researchers as the next hope for finding a viable therapeutic target in AD. Interestingly, it appears that the autophagy and mitophagy are also changed in these cells in AD. Inside the cells, autophagy and inflammation interact in a bidirectional manner. In the current review, we briefly discussed an overview on autophagy and mitophagy in AD and then provided a comprehensive discussion on the role of these pathways in microglia and their involvement in AD pathogenesis.

Activation of CREB-mediated autophagy by thioperamide ameliorates β-amyloid pathology and cognition in Alzheimer's disease

Alzheimer's disease (AD) is an age-related neurodegenerative disease, and the imbalance between production and clearance of β-amyloid (Aβ) is involved in its pathogenesis. Autophagy is an intracellular degradation pathway whereby leads to removal of aggregated proteins, up-regulation of which may be a plausible therapeutic strategy for the treatment of AD. Histamine H3 receptor (H3R) is a presynaptic autoreceptor regulating histamine release via negative feedback way. Our previous study showed that thioperamide, as an antagonist of H3R, enhances autophagy and protects against ischemic injury. However, the effect of thioperamide on autophagic function and Aβ pathology in AD remains unknown. In this study, we found that thioperamide promoted cognitive function, ameliorated neuronal loss, and Aβ pathology in APP/PS1 transgenic (Tg) mice. Interestingly, thioperamide up-regulated autophagic level and lysosomal function both in APP/PS1 Tg mice and in primary neurons under Aβ-induced injury. The neuroprotection by thioperamide against AD was reversed by 3-MA, inhibitor of autophagy, and siRNA of Atg7, key autophagic-related gene. Furthermore, inhibition of activity of CREB, H3R downstream signaling, by H89 reversed the effect of thioperamide on promoted cell viability, activated autophagic flux, and increased autophagic-lysosomal proteins expression, including Atg7, TFEB, and LAMP1, suggesting a CREB-dependent autophagic activation by thioperamide in AD. Taken together, these results suggested that H3R antagonist thioperamide improved cognitive impairment in APP/PS1 Tg mice via modulation of the CREB-mediated autophagy and lysosomal pathway, which contributed to Aβ clearance. This study uncovered a novel mechanism involving autophagic regulating behind the therapeutic effect of thioperamide in AD.

Beyond Antioxidant Effects: Nature-Based Templates Unveil New Strategies for Neurodegenerative Diseases

The complex network of malfunctioning pathways occurring in the pathogenesis of neurodegenerative diseases (NDDs) represents a huge hurdle in the development of new effective drugs to be used in therapy. In this context, redox reactions act as crucial regulators in the maintenance of neuronal microenvironment homeostasis. Particularly, their imbalance results in the severe compromising of organism’s natural defense systems and subsequently, in the instauration of deleterious OS, that plays a fundamental role in the insurgence and progress of NDDs. Despite the huge efforts in drug discovery programs, the identification process of new therapeutic agents able to counteract the relentless progress of neurodegenerative processes has produced low or no effective therapies. Consequently, a paradigm-shift in the drug discovery approach for these diseases is gradually occurring, paving the way for innovative therapeutical approaches, such as polypharmacology. The aim of this review is to provide an overview of the main pharmacological features of most promising nature-based scaffolds for a possible application in drug discovery, especially for NDDs, highlighting their multifaceted effects against OS and neuronal disorders.

Alzheimer's disease treatment: The share of herbal medicines

One of the most frequent forms of dementia in neurological disorders is Alzheimer's disease (AD). It is a chronic neurodegenerative disease characterized by impaired learning and memory. Pathological symptoms as extracellular amyloid-beta (Aβ) plaques and intracellular accumulation of neurofibrillary tangles occur in AD. Due to the aging of the population and increased prevalence of AD, discovery of new therapeutic agents with the highest effectiveness and fewer side effect seems to be necessary. Numerous synthetic medicines such as tacrine, donepezil, galantamine, rivastigmine, memantine, glutathione, ascorbic acid, ubiquinone, ibuprofen, and ladostigil are routinely used for reduction of the symptoms and prevention of disease progression. Nowadays, herbal medicines have attracted popular attention for numerous beneficial effects with little side effects. Lavandula angustifolia, Ginkgo biloba, Melissa officinalis, Crocus sativus, Ginseng, Salvia miltiorrhiza, and Magnolia officinalis have been widely used for relief of symptoms of some neurological disorders. This paper reviews the therapeutic effects of phytomedicines with prominent effects against various factors implicated in the emergence and progression of AD.

Essential Oil of Acorus tatarinowii Schott Ameliorates Aβ-Induced Toxicity in Caenorhabditis elegans through an Autophagy Pathway

Background

Acorus tatarinowii Schott [Shi Chang Pu in Chinese (SCP)] is a traditional Chinese medicine frequently used in the clinical treatment of dementia, amnesia, epilepsy, and other mental disorders. Previous studies have shown the potential efficacy of SCP against Alzheimer's disease (AD). Nevertheless, the active constituents and the modes of action of SCP in AD treatment have not been fully elucidated.

Purpose

The aim of this study was to investigate the protective effects of SCP on abnormal proteins and clarify its molecular mechanisms in the treatment of AD by using a Caenorhabditis elegans (C. elegans) model.

Methods

This study experimentally assessed the effect of SCP-Oil in CL4176 strains expressing human Aβ in muscle cells and CL2355 strains expressing human Aβ in pan-neurons. Western blotting, qRT-PCR, and fluorescence detection were performed to determine the oxidative stress and signaling pathways affected by SCP-Oil in nematodes.

Results

SCP-Oil could significantly reduce the deposition of misfolded Aβ and polyQ proteins and improved serotonin sensitivity and olfactory learning skill in worms. The analysis of pharmacological action mechanism of SCP-Oil showed that its maintaining protein homeostasis is dependent on the autophagy pathway regulated partly by hsf-1 and sir-2.1 genes.

Conclusion

Our results provide new insights to develop treatment strategy for AD by targeting autophagy, and SCP-Oil could be an alternative drug for anti-AD.

Neurodegenerative Pathways in Alzheimer's Disease: A Review

Alzheimer's disease (AD) is a complex neurodegenerative disease that leads to insidious deterioration of brain functions and is considered the sixth leading cause of death in the world. Alzheimer's patients suffer from memory loss, cognitive deficit and behavioral changes; thus, they eventually follow a low-quality life. AD is considered as a multifactorial disorder involving different neuropathological mechanisms. Recent research has identified more than 20 pathological factors that are promoting disease progression. Three significant hypotheses are said to be the root cause of disease pathology, which include acetylcholine deficit, the formation of amyloid-beta senile plaques and tau protein hyperphosphorylation. Apart from these crucial factors, pathological factors such as apolipoprotein E (APOE), glycogen synthase kinase 3β, notch signaling pathway, Wnt signaling pathway, etc., are considered to play a role in the advancement of AD and therefore could be used as targets for drug discovery and development. As of today, there is no complete cure or effective disease altering therapies for AD. The current therapy is assuring only symptomatic relief from the disease, and progressive loss of efficacy for these symptomatic treatments warrants the discovery of newer drugs by exploring these novel drug targets. A comprehensive understanding of these therapeutic targets and their neuropathological role in AD is necessary to identify novel molecules for the treatment of AD rationally.

Modulatory Effects of Autophagy on APP Processing as a Potential Treatment Target for Alzheimer's Disease

Alzheimer’s disease (AD) is characterized by the formation of intracellular aggregate composed of heavily phosphorylated tau protein and extracellular deposit of amyloid-β (Aβ) plaques derived from proteolysis cleavage of amyloid precursor protein (APP). Autophagy refers to the lysosomal-mediated degradation of cytoplasmic constituents, which plays a critical role in maintaining cellular homeostasis. Importantly, recent studies reported that dysregulation of autophagy is associated in the pathogenesis of AD, and therefore, autophagy modulation has gained attention as a promising approach to treat AD pathogenesis. In AD, both the maturation of autolysosomes and its retrograde transports have been obstructed, which causes the accumulation of autophagic vacuoles and eventually leads to degenerating and dystrophic neurites function. However, the mechanism of autophagy modulation in APP processing and its pathogenesis have not yet been fully elucidated in AD. In the early stage of AD, APP processing and Aβ accumulation-mediated autophagy facilitate the removal of toxic protein aggregates via mTOR-dependent and -independent pathways. In addition, a number of autophagy-related genes (Atg) and APP are thought to influence the development of AD, providing a bidirectional link between autophagy and AD pathology. In this review, we summarized the current observations related to autophagy regulation and APP processing in AD, focusing on their modulation associated with the AD progression. Moreover, we emphasizes the application of small molecules and natural compounds to modulate autophagy for the removal and clearance of APP and Aβ deposits in the pathological condition of AD.

Autophagy and metabolism

Metabolism consists of diverse life-sustaining chemical reactions in living organisms. Autophagy is a highly conservative process that responds to various internal and external stresses. Both processes utilize surrounding resources to provide energy and nutrients for the cell. Autophagy progression may proceed to the degradative or secretory pathway determined by Rab family proteins. The former is a degradative and lysosome-dependent catabolic process that produces energy and provides nutrients for the synthesis of essential proteins. The degradative pathway also balances the energy source of the cell and regulates tissue homeostasis. The latter is a newly discovered pathway in which the autophagosome is fused with the plasma membrane. Secretory autophagy participates in diverse functions and diseases ranging from the spread of viral particles to cancer and neurodegenerative diseases. Aberrant metabolism in the body causes various metabolic syndromes. This review explores the relationships among autophagy, metabolism, and related diseases.

Natural Compounds and Autophagy: Allies Against Neurodegeneration

Prolonging the healthy life span and limiting neurological illness are imperative goals in gerontology. Age-related neurodegeneration is progressive and leads to severe diseases affecting motility, memory, cognitive function, and social life. To date, no effective treatments are available for neurodegeneration and irreversible neuronal loss. Bioactive phytochemicals could represent a natural alternative to ensure active aging and slow onset of neurodegenerative diseases in elderly patients. Autophagy or macroautophagy is an evolutionarily conserved clearing process that is needed to remove aggregate-prone proteins and organelles in neurons and glia. It also is crucial in synaptic plasticity. Aberrant autophagy has a key role in aging and neurodegeneration. Recent evidence indicates that polyphenols like resveratrol and curcumin, flavonoids, like quercetin, polyamine, like spermidine and sugars, like trehalose, limit brain damage in vitro and in vivo. Their common mechanism of action leads to restoration of efficient autophagy by dismantling misfolded proteins and dysfunctional mitochondria. This review focuses on the role of dietary phytochemicals as modulators of autophagy to fight Alzheimer's and Parkinson's diseases, fronto-temporal dementia, amyotrophic lateral sclerosis, and psychiatric disorders. Currently, most studies have involved in vitro or preclinical animal models, and the therapeutic use of phytochemicals in patients remains limited.

Boosting the autophagy-lysosomal pathway by phytochemicals: A potential therapeutic strategy against Alzheimer's disease

The lysosome is a membrane-enclosed organelle in eukaryotic cells, which has basic pattern recognition for nutrient-dependent signal transduction. In Alzheimer's disease, the already declining autophagy-lysosomal function is exacerbated by an increased need for clearance of damaged proteins and organelles in aged cells. Recent evidence suggests that numerous diseases are linked to impaired autophagy upstream of lysosomes. In this way, a comprehensive survey on the pathophysiology of the disease seems necessary. Hence, in the first section of this review, we will discuss the ultimate findings in lysosomal signaling functions and how they affect cellular metabolism and trafficking under neurodegenerative conditions, specifically Alzheimer's disease. In the second section, we focus on how natural products and their derivatives are involved in the regulation of inflammation and lysosomal dysfunction pathways, including how these should be considered a crucial target for Alzheimer's disease therapeutics.

p62: Friend or Foe? Evidences for OncoJanus and NeuroJanus Roles

p62 is a versatile protein involved in the delicate balance between cell death and survival, which is fundamental for cell fate decision in the context of both cancer and neurodegenerative diseases. As an autophagy adaptor, p62 recognizes polyubiquitin chains and interacts with LC3, thereby targeting the selected cargo to the autophagosome with consequent autophagic degradation. Beside this function, p62 behaves as an interactive hub in multiple signalling including those mediated by Nrf2, NF-κB, caspase-8, and mTORC1. The protein is thus crucial for the control of oxidative stress, inflammation and cell survival, apoptosis, and metabolic reprogramming, respectively. As a multifunctional protein, p62 falls into the category of those factors that can exert opposite roles in the cells. Chronic p62 accumulation was found in many types of tumors as well as in stress granules present in different forms of neurodegenerative diseases. However, the protein seems to have a Janus behaviour since it may also serve protective functions against tumorigenesis or neurodegeneration. This review describes the diversified roles of p62 through its multiple domains and interactors and specifically focuses on its oncoJanus and neuroJanus roles.

Interplay Between Mitochondrial Oxidative Disorders and Proteostasis in Alzheimer's Disease

Although the basis of Alzheimer’s disease (AD) etiology remains unknown, oxidative stress (OS) has been recognized as a prodromal factor associated to its progression. OS refers to an imbalance between oxidant and antioxidant systems, which usually consist in an overproduction of reactive oxygen species (ROS) and reactive nitrogen species (RNS) which overwhelms the intrinsic antioxidant defenses. Due to this increased production of ROS and RNS, several biological functions such as glucose metabolism or synaptic activity are impaired. In AD, growing evidence links the ROS-mediated damages with molecular targets including mitochondrial dynamics and function, protein quality control system, and autophagic pathways, affecting the proteostasis balance. In this scenario, OS should be considered as not only a major feature in the pathophysiology of AD but also a potential target to combat the progression of the disease. In this review, we will discuss the role of OS in mitochondrial dysfunction, protein quality control systems, and autophagy associated to AD and suggest innovative therapeutic strategies based on a better understanding of the role of OS and proteostasis.

Protocatechuic acid attenuates β‑secretase activity and okadaic acid‑induced autophagy via the Akt/GSK‑3β/MEF2D pathway in PC12 cells

Okadaic acid (OA) can be used to induce an Alzheimer's disease (AD) model characterized by tau hyperphosphorylation, the formation of neurofibrillary tangles formation and β‑amyloid (Aβ) deposition. Previous studies have shown that the upregulation of Beclin‑1‑dependent autophagy may contribute to the elimination of aggregated Aβ. However, the effects of protocatechuic acid (PA) on the levels of Aβ42, phosphorylated (p)‑tau and β‑secretase in OA‑induced cell injury are unclear, and little is known concerning the role of the PA signaling pathway in the regulation of autophagy. The present study aimed to determine whether PA protects cells from OA‑induced cytotoxicity via the regulation of Beclin‑1‑dependent autophagy and its regulatory signaling pathway. PC12 cells were treated with OA with or without PA for 24 h. Enzymatic assays were performed to measure p‑tau, Aβ42 and β‑secretase activity. Western blotting was performed to detect p‑Akt, p‑glycogen synthase kinase‑3β (p‑GSK‑3β), Akt, GSK‑3β, myocyte enhancer factor 2D (MEF2D) and Beclin‑1 protein expression levels. Immunofluorescence and immunocytochemistry were used to measure Beclin‑1 expression levels. The results from this study showed that PA could increase cell viability and significantly decrease the levels of Aβ42, p‑tau, β‑secretase and Beclin‑1. PA can also promote the expression of p‑Akt and MEF2D while suppressing the expression of p‑GSK‑3β. These results indicated that PA protects PC12 cells from OA‑induced cytotoxicity, and attenuates autophagy via regulation of the Akt/GSK‑3β/MEF2D pathway, therefore potentially contributing to the neuroprotective effects of PA against OA toxicity. These findings suggested that PA may have potential as a drug candidate in preventative AD therapy.

A Network Pharmacology Approach to Reveal the Underlying Mechanisms of Paeonia lactiflora Pall. On the Treatment of Alzheimer's Disease

OBJECTIVE

To investigate the potential active compounds and underlying mechanisms of Paeonia lactiflora Pall. (PLP) on the treatment of Alzheimer's disease (AD) based on network pharmacology.

METHODS

The active components of PLP were collected from Traditional Chinese Medicine System Pharmacology (TCMSP) database, and their possible target proteins were predicted using TCMSP, SwissTargetPrediction, and STITCH databases. The putative AD-related target proteins were identified from Therapeutic Target Database (TTD), GeneCards, and MalaCards database. The compound-target-disease network interactions were established to obtain the key targets about PLP acting on AD by network topology analysis. Then, the function annotation and signaling pathways of key targets were performed by GO and KEGG enrichment analysis using DAVID tools. Finally, the binding capacity between active ingredients and key targets was validated by molecular docking using SystemsDock tools.

RESULTS

There were 7 active compounds involving in 151 predicted targets identified in PLP. Besides, a total of 160 AD-related targets were identified. Among these targets, 30 shared targets of PLP and AD were acquired. After topological analysis of the PLP potential target-AD target network, 33 key targets that were highly responsible for the therapeutic effects of PLP on AD were obtained. Further GO and KEGG enrichment analysis showed that these key targets were significantly involved in multiple biological processes and pathways which participated in cell apoptosis and inflammatory response and maintained the function of neurons to accomplish the anti-AD activity. The molecular docking analysis verified that the 7 active compounds had definite affinity with the key targets.

CONCLUSIONS

The ameliorative effects of PLP on AD were predicted to be associated with regulating neural cell apoptosis, inflammatory response, and neurotrophy via various pathways such as PI3K-Akt signaling pathway, MAPK signaling pathway, and neurotrophin signaling pathway.

Hochu-Ekki-To Improves Motor Function in an Amyotrophic Lateral Sclerosis Animal Model

Hochu-ekki-to (Bojungikgi-Tang (BJIGT) in Korea; Bu-Zhong-Yi-Qi Tang in Chinese), a traditional herbal prescription, has been widely used in Asia. Hochu-ekki-to (HET) is used to enhance the immune system in respiratory disorders, improve the nutritional status associated with chronic diseases, enhance the mucosal immune system, and improve learning and memory. Amyotrophic lateral sclerosis (ALS) is pathologically characterized by motor neuron cell death and muscle paralysis, and is an adult-onset motor neuron disease. Several pathological mechanisms of ALS have been reported by clinical and in vitro/in vivo studies using ALS models. However, the underlying mechanisms remain elusive, and the critical pathological target needs to be identified before effective drugs can be developed for patients with ALS. Since ALS is a disease involving both motor neuron death and skeletal muscle paralysis, suitable therapy with optimal treatment effects would involve a motor neuron target combined with a skeletal muscle target. Herbal medicine is effective for complex diseases because it consists of multiple components for multiple targets. Therefore, we investigated the effect of the herbal medicine HET on motor function and survival in hSOD1^G93A transgenic mice. HET was orally administered once a day for 6 weeks from the age of 2 months (the pre-symptomatic stage) of hSOD1^G93A transgenic mice. We used the rota-rod test and foot printing test to examine motor activity, and Western blotting and H&E staining for evaluation of the effects of HET in the gastrocnemius muscle and lumbar (L4–5) spinal cord of mice. We found that HET treatment dramatically inhibited inflammation and oxidative stress both in the spinal cord and gastrocnemius of hSOD1^G93A transgenic mice. Furthermore, HET treatment improved motor function and extended the survival of hSOD1^G93A transgenic mice. Our findings suggest that HET treatment may modulate the immune reaction in muscles and neurons to delay disease progression in a model of ALS.

A combined molecular biology and network pharmacology approach to investigate the multi-target mechanisms of Chaihu Shugan San on Alzheimer's disease

Chaihu Shugan San (CSS) is a well-known herbal formula used to nourish liver and blood, promote blood circulation and Qi flow in Traditional Chinese Medicine. Modern pharmacological studies and clinical uses showed that CSS could ameliorate cognitive dysfunction of Alzheimer's disease (AD). The present study aimed to elucidate the multi-target mechanisms of CSS on AD using network pharmacology analysis and verify its effect by biological experiments. Firstly, a total of 152 active compounds in CSS, 520 predicted biological targets and 160 AD-related targets were identified. Subsequently, the networks including herb-compound-target network, AD-target network, and CSS potential target-AD target network were constructed. 60 key targets highly responsible for the beneficial effect of CSS on AD were identified by central network topological analysis. They were significantly characterized as nuclear or cytoplasmic proteins with molecular function of protein binding. They were also enriched in various biological processes through PI3K-Akt signaling pathway, MAPK signaling pathway and HIF signaling pathway by GO function and KEGG pathway enrichment analysis. Pretreatment with CSS ameliorated Aβ-induced neural cell death and reduced the number of apoptotic cells in differentiated PC12 cells. Moreover, increased phosphorylation of Akt accompanied with decreased Bax expression was found after CSS pretreatment, suggesting that Akt signaling pathway was involved in the protective effect of CSS against neural cells death. The present study systematically revealed the multi-target mechanisms of CSS on AD using network pharmacology approach, as well as validated the protective effect of CSS against Aβ-induced neural cells death through Akt signaling pathway. It provided indications for further mechanistic studies and also for the development of CSS as a potential treatment for AD patients.

Effects of newly introduced antidiabetic drugs on autophagy

Diabetes mellitus is a chronic metabolic disorder that has a complex molecular and cellular pathophysiology, resulting in its dynamic progression and that may show differing responses to therapy. The incidence of diabetes mellitus increases with age and requires additive therapeutic agents for its management. SGLT2i and DPP-4 inhibitors and GLP-1 receptor agonists (GLP-1RA) are newly introduced antidiabetic drugs that work through differing mechanisms; DPP-4 inhibitors maintain the endogenous level of GLP1; GLP-1RA result in pharmacological levels of GLP1, whilst SGLT2i act on the proximal tubules of the kidney. They have shown efficacy in the management of diabetes and in contrast to other antidiabetic drugs, do not inherently cause hypoglycemia in therapeutic doses. Autophagy as a highly conserved mechanism to maintain cell survival and homeostasis by degradation of damaged or aged organelles and components, and recognised to be increasingly important in diabetes. In the present review, we discuss the modulatory effects of these newly introduced antidiabetic drugs on the autophagy process.