Tetrahydroxy stilbene glycoside alleviated inflammatory damage by mitophagy via AMPK related PINK1/Parkin signaling pathway

Mitophagy in Neurodegenerative Diseases: Mechanisms of Action and the Advances of Drug Discovery

Neurodegenerative diseases (NDDs), such as Parkinson's disease (PD) and Alzheimer's disease (AD), are devastating brain diseases and are incurable at the moment. Increasing evidence indicates that NDDs are associated with mitochondrial dysfunction. Mitophagy removes defective or redundant mitochondria to maintain cell homeostasis, whereas deficient mitophagy accelerates the accumulation of damaged mitochondria to mediate the pathologies of NDDs. Therefore, targeting mitophagy has become a valuable therapeutic pathway for the treatment of NDDs. Several mitophagy modulators have been shown to ameliorate neurodegeneration in PD and AD. However, it remains to be further investigated for other NDDs. Here, we describe the mechanism and key signaling pathway of mitophagy and summarize the roles of defective mitophagy on the pathogenesis of NDDs. Further, we underline the development advances of mitophagy modulators for PD and AD therapy, discuss the therapeutic challenges and limitations of the existing modulators, and provide guidelines for mitophagy mechanism exploration and drug design.

Unraveling mitochondrial dysfunction: comprehensive perspectives on its impact on neurodegenerative diseases

Neurodegenerative diseases represent a significant challenge to modern medicine, with their complex etiology and progressive nature posing hurdles to effective treatment strategies. Among the various contributing factors, mitochondrial dysfunction has emerged as a pivotal player in the pathogenesis of several neurodegenerative disorders. This review paper provides a comprehensive overview of how mitochondrial impairment contributes to the development of neurodegenerative diseases including Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis, driven by bioenergetic defects, biogenesis impairment, alterations in mitochondrial dynamics (such as fusion or fission), disruptions in calcium buffering, lipid metabolism dysregulation and mitophagy dysfunction. It also covers current therapeutic interventions targeting mitochondrial dysfunction in these diseases.

Stilbene glycosides alleviate atherosclerosis partly by promoting lipophagy of dendritic cells

Atherosclerosis (AS) is a chronic inflammatory disease resulting from lipid metabolism disorders and immune imbalances. Dendritic cells (DCs) are key cells that regulate adaptive and adaptive immunity. When DCs engulf excessive amounts lipids, their function is altered, thereby, accelerating the inflammatory process of AS. Cellular lipophagy serves to reduce lipid accumulation and maintain cellular lipid metabolism balance. In this study, we investigated the effectiveness of 2,3,5,4'-tetrahydroxystilbene 2-O-β-D-glucoside (TSG) in intervening in the promotion of DCs lipid accumulation by ox-LDL, as well as its role in downregulating lipophagy. Our findings indicate that TSG reduces the maturity of DCs and promotes the differentiation of T cells towards Treg, thereby correcting the imbalanced Treg/Th17. These effects of TSG are closely associated with its inhibition of the PI3K-AKT-mTOR signaling pathway. After administering TSG to ApoE-/- mice that were fed a high-fat diet, there was a noticeable decrease in harmful blood lipids found in the serum. Additionally, the imbalanced Treg/Th17 levels in the spleen were restored, and the levels of pro-inflammatory factor IL-6 and IL-17A in the serum decreased, while the level of anti-inflammatory factor IL-10 increased. Furthermore, the arterial DCs showed a decrease in P62 content. Ultimately, these changes resulted in a reduction in plaque area. It is worth noting that the autophagy inhibitor chloroquine significantly altered the effects of TSG on ApoE-/- mice. In conclusion, this study reveals that TSG can alleviate AS. This is partly achieved through the activation of autophagy in DCs. By intervening in the lipophagy of DCs, it is possible to regulate the immune function of these cells, which in turn helps control the inflammation associated with AS. This presents a potential method for intervening in AS.

Therapeutic potential of Parkin and its regulation in Parkinson's disease

Parkinson's disease (PD) is a debilitating neurodegenerative disorder characterized by the progressive loss of dopaminergic neurons in the midbrain substantia nigra, resulting in motor and non-motor symptoms. While the exact etiology of PD remains elusive, a growing body of evidence suggests that dysfunction in the parkin protein plays a pivotal role in the pathogenesis of the disease. Parkin is an E3 ubiquitin ligase that ubiquitinates substrate proteins to control a number of crucial cellular processes including protein catabolism, immune response, and cellular apoptosis.While autosomal recessive mutations in the PARK2 gene, which codes for parkin, are linked to an inherited form of early-onset PD, heterozygous mutations in PARK2 have also been reported in the more commonly occurring sporadic PD cases. Impairment of parkin's E3 ligase activity is believed to play a pathogenic role in both familial and sporadic forms of PD.This article provides an overview of the current understanding of the mechanistic basis of parkin's E3 ligase activity, its major physiological role in controlling cellular functions, and how these are disrupted in familial and sporadic PD. The second half of the manuscript explores the currently available and potential therapeutic strategies targeting parkin structure and/or function in order to slow down or mitigate the progressive neurodegeneration in PD.

Tetrahydroxy Stilbene Glucoside Promotes Mitophagy and Ameliorates Neuronal Injury after Cerebral Ischemia Reperfusion via Promoting USP10-Mediated YBX1 Stability

Tetrahydroxy stilbene glucoside (TSG) from Polygonum multiflorum exerts neuroprotective effects after ischemic stroke. We explored whether TSG improved ischemic stroke injury via PTEN-induced kinase 1 (PINK1)/Parkin-mediated mitophagy. Oxygen glucose deprivation/reoxygenation (OGD/R) in vitro model and middle cerebral artery occlusion (MCAO) rat model were established. Cerebral injury was assessed by neurological score, hematoxylin and eosin staining, 2,3,5-triphenyltetrazolium chloride staining, and brain water content. Apoptosis, cell viability, and mitochondrial membrane potential were assessed by flow cytometry, cell counting kit-8, and JC-1 staining, respectively. Colocalization of LC3-labeled autophagosomes with lysosome-associated membrane glycoprotein 2-labeled lysosomes or translocase of outer mitochondrial membrane 20-labeled mitochondria was observed with fluorescence microscopy. The ubiquitination level was determined using ubiquitination assay. The interaction between molecules was validated by coimmunoprecipitation and glutathione S-transferase pull-down. We found that TSG promoted mitophagy and improved cerebral ischemia/reperfusion damage in MCAO rats. In OGD/R-subjected neurons, TSG promoted mitophagy, repressed neuronal apoptosis, upregulated Y-box binding protein-1 (YBX1), and activated PINK1/Parkin signaling. TSG upregulated ubiquitin-specific peptidase 10 (USP10) to elevate YBX1 protein. Furthermore, USP10 inhibited ubiquitination-dependent YBX1 degradation. USP10 overexpression activated PINK1/Parkin signaling and promoted mitophagy, which were reversed by YBX1 knockdown. Moreover, TSG upregulated USP10 to promote mitophagy and inhibited neuronal apoptosis. Collectively, TSG facilitated PINK1/Parkin pathway-mediated mitophagy by upregulating USP10/YBX1 axis to ameliorate ischemic stroke.

Phytochemicals targeting mitophagy: Therapeutic opportunities and prospects for treating Alzheimer's disease

Alzheimer's disease (AD) is a prevalent neurodegenerative disorder and the leading cause of age-related cognitive decline. Recent studies have established a close relationship between mitophagy and the pathogenesis of AD. Various phytochemicals have shown promising therapeutic effects in mitigating the onset and progression of AD. This review offers a comprehensive overview of the typical features of mitophagy and the underlying mechanisms leading to its occurrence in AD, highlighting its significance in the disease's pathogenesis and progression. Additionally, we examine the therapeutic mechanisms of synthetic drugs that induce mitophagy in AD. Finally, we summarize recent advances in research on phytochemicals that regulate mitophagy in the treatment of AD, potentially guiding the development of new anti-AD drugs.

THSG alleviates cerebral ischemia/reperfusion injury via the GluN2B-CaMKII-ERK1/2 pathway

BACKGROUND

The potential therapeutic targeting of PINK1-PARK2-mediated mitophagy against cerebral ischemia/reperfusion (CI/R) injury involves the pathophysiological processes of neurovascular unit (NVU) and is closely associated with N-methyl-D-aspartate receptors (NMDARs) commonly expressed in NVU. 2,3,5,4'-Tetrahydroxy-stilbene-2-O-β-D-glucoside (THSG), a compound derived from the traditional Chinese medicine Polygonum multiflorum Thunb., has demonstrated notable neuroprotective properties against CI/R injury. However, it remains unclear whether THSG exerts its protective effects through GluN2B related PINK1/ PARK2 pathway.

PURPOSE

This study aims to explore the pharmacological effects of THSG on alleviating CI/R injury via the GluN2B-CaMKII-ERK1/2 pathway.

METHODS

THSG neuroprotection against CI/R injury was studied in transient middle cerebral artery occlusion/reversion (tMCAO/R) model rats and in oxygen and glucose deprivation/ reoxygenation (OGD/R) induced neurons. PINK1-PARK2-mediated mitophagy involvement in the protective effect of THSG was investigated in tMCAO/R rats and OGD/R-induced neurons via THSG and 3-methyladenine (3-MA) treatment. Furthermore, the beneficial role of GluN2B in reperfusion and its contribution to the THSG effect via CaMKII-ERK1/2 and PINK1-PARK2-mediated mitophagy was explored using the GluN2B-selective antagonist Ro 25-6981 both in vivo and in vitro. Finally, the interaction between THSG and GluN2B was evaluated using molecular docking.

RESULTS

THSG significantly reduced infarct volume, neurological deficits, penumbral neuron structure, and functional damage, upregulated the inhibitory apoptotic marker Bcl-2, and suppressed the increase of pro-apoptotic proteins including cleaved caspase-3 and Bax in tMCAO/R rats. THSG (1 μM) markedly improved the neuronal survival under OGD/R conditions. Furthermore, THSG promoted PINK1 and PARK2 expression and increased mitophagosome numbers and LC3-II-LC3-I ratio both in vivo and in vitro. The effects of THSG were considerably abrogated by the mitophagy inhibitor 3-MA in OGD/R-induced neurons. Inhibiting GluN2B profoundly decreased mitophagosome numbers and OGD/R-induced neuronal viability. Specifically, inhibiting GluN2B abolished the protection of THSG against CI/R injury and reversed the upregulation of PINK1-PARK2-mediated mitophagy by THSG. Inhibiting GluN2B eliminated THSG upregulation of ERK1/2 and CaMKII phosphorylation. The molecular docking analysis results demonstrated that THSG bound to GluN2B (binding energy: -5.2 ± 0.11 kcal/mol).

CONCLUSIONS

This study validates the premise that THSG alleviates CI/R injury by promoting GluN2B expression, activating CaMKII and ERK1/2, and subsequently enhancing PINK1-PARK2-mediated mitophagy. This work enlightens the potential of THSG as a promising candidate for novel therapeutic strategies for treating ischemic stroke.

Preclinical Evidence and Underlying Mechanisms of Polygonum multiflorum and Its Chemical Constituents Against Cognitive Impairments and Alzheimer's Disease

Objectives

Cognitive impairments, ranging from mild to severe, adversely affect daily functioning, quality of life, and work capacity. Despite significant efforts in the past decade, more than 200 promising drug candidates have failed in clinical trials. Herbal remedies are gaining interest as potential treatments for dementia due to their long history and safety, making them valuable for drug development. This review aimed to examine the mechanisms behind the effect of Polygonum multiflorum on cognitive function.

Methods

This study focused primarily on the effects of Polygonum multiflorum and its chemical constituents on cognitive behavioral outcomes including the Morris water maze, the passive avoidance test, and the Y maze, as well as pathogenic targets of cognitive impairment and Alzheimer's disease (AD) like amyloid deposition, amyloid precursor protein, tau hyperphosphorylation, and cognitive decline. Additionally, a thorough evaluation of the mechanisms behind Polygonum multiflorum's impact on cognitive function was conducted. We reviewed the most recent data from preclinical research done on experimental models, particularly looking at Polygonum multiflorum's effects on cognitive decline and AD.

Results

According to recent research, Poligonum multiflorum and its bioactive components, stilbene, and emodin, influence cognitive behavioral results and regulate the pathological target of cognitive impairment and AD. Their mechanisms of action include reducing oxidative and mitochondrial damage, regulating neuroinflammation, halting apoptosis, and promoting increased neurogenesis and synaptogenesis.

Conclusion

This review serves as a comprehensive compilation of current experiments on AD and other cognitive impairment models related to the therapeutic effects of Polygonum multiflorum. We believe that these findings can serve as a basis for future clinical trials and have potential applications in the treatment of human neurological disorders.

Phytochemicals targeting Alzheimer's disease via the AMP-activated protein kinase pathway, effects, and mechanisms of action

Alzheimer's disease (AD), characterized by cognitive dysfunction and other behavioral abnormalities, is a progressive neurodegenerative disease that occurs due to aging. Currently, effective drugs to mitigate or treat AD remain unavailable. AD is associated with several abnormalities in neuronal energy metabolism, such as decreased glucose uptake, mitochondrial dysfunction, and defects in cholesterol metabolism. Amp-activated protein kinase (AMPK) is an important serine/threonine protein kinase that regulates the energy status of cells. AMPK is widely present in eukaryotic cells and can sense and regulate energy metabolism to maintain energy supply and demand balance, making it a promising target for energy metabolism-based AD therapy. Therefore, this review aimed to discuss the molecular mechanism of AMPK in the pathogenesis of AD to provide a theoretical basis for the development of new anti-AD drugs. To review the mechanisms of phytochemicals in the treatment of AD via AMPK pathway regulation, we searched PubMed, Google Scholar, Web of Science, and Embase databases using specific keywords related to AD and phytochemicals in September 2023. Phytochemicals can activate AMPK or regulate the AMPK pathway to exert therapeutic effects in AD. The anti-AD mechanisms of these phytochemicals include inhibiting Aβ aggregation, preventing Tau hyperphosphorylation, inhibiting inflammatory response and glial activation, promoting autophagy, and suppressing anti-oxidative stress. Additionally, several AMPK-related pathways are involved in the anti-AD mechanism, including the AMPK/CaMKKβ/mTOR, AMPK/SIRT1/PGC-1α, AMPK/NF-κB/NLRP3, AMPK/mTOR, and PERK/eIF2α pathways. Notably, urolithin A, artemisinin, justicidin A, berberine, stigmasterol, arctigenin, and rutaecarpine are promising AMPK agonists with anti-AD effects. Several phytochemicals are effective AMPK agonists and may have potential applications in AD treatment. Overall, phytochemical-based drugs may overcome the barriers to the effective treatment of neurodegenerative diseases.

Research Progress of Mitophagy in Alzheimer's Disease

The prevalence of Alzheimer's disease (AD) is increasing as the elderly population, which hurts elderly people's cognition and capacity for self-care. The process of mitophagy involves the selective clearance of ageing and impaired mitochondria, which is required to preserve intracellular homeostasis and energy metabolism. Currently, it has been discovered that mitophagy abnormalities are intimately linked to the beginning and progression of AD. This article discusses the mechanism of mitophagy, abnormal mitophagy, and therapeutic effects in AD. The purpose is to offer fresh perspectives on the causes and remedies of AD.

Stabilization of mitochondrial function by chlorogenic acid protects against kainic acid-induced seizures and neuronal cell death in rats

The current study investigated the effect of chlorogenic acid, a polyphenolic compound found in numerous plant products, on a kainic acid-induced seizure rat model and its potential mechanism. Rats were administered chlorogenic acid (10 and 50 mg/kg) intraperitoneally for 30 min before kainic acid (15 mg/kg) intraperitoneal administration. Pretreatment with chlorogenic acid decreased the seizure score, increased the latency to onset of the first seizure, and decreased the mortality rate. Chlorogenic acid pretreatment also resulted in a significant reduction in glutamate elevation and neuronal death in the hippocampus of kainic acid-treated rats. In addition, electron microscopy revealed that kainic acid-induced changes in hippocampal mitochondrial structure were prevented by chlorogenic acid pretreatment. Additionally, the levels of mitochondrial function-related proteins, including sirtuin 3, Complex I, glutamate dehydrogenase 1 and ATP synthase, were increased, and the level of the mitochondrial damage marker cytochrome C was decreased in the hippocampus of chlorogenic acid/kainic acid rats. Furthermore, the expression of mitochondrial biogenesis-related proteins [AMP-activated protein kinase (AMPK), sirtuin1, and peroxisome proliferator-activated receptor γ-coactivator-1α (PGC-1α)] and mitophagy-related proteins [phosphatase and tensin homolog (PTEN)-induced putative kinase 1 (PINK1), Parkin, and microtubule-associated protein 1 light chain 3 (LC3)] was decreased in the hippocampus of kainic acid-treated rats, which was reversed by chlorogenic acid pretreatment. These observations reveal the marked neuroprotective potential of chlorogenic acid against kainic acid-induced neurotoxicity and seizures through prevention of glutamate increase and preservation of AMPK/sirtuin 1/PGC-1α-mediated mitochondrial biogenesis and PINK1/Parkin-induced mitophagy to maintain adequate mitochondrial homeostasis and function.

Targeting mitophagy for neurological disorders treatment: advances in drugs and non-drug approaches

Mitochondria serve as a vital energy source for nerve cells. The mitochondrial network also acts as a defense mechanism against external stressors that can threaten the stability of the nervous system. However, excessive accumulation of damaged mitochondria can lead to neuronal death. Mitophagy is an essential pathway in the mitochondrial quality control system and can protect neurons by selectively removing damaged mitochondria. In most neurological disorders, dysfunctional mitochondria are a common feature, and drugs that target mitophagy can improve symptoms. Here, we reviewed the role of mitophagy in Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, Huntington's disease, stroke, and traumatic brain injuries. We also summarized drug and non-drug approaches to promote mitophagy and described their therapeutic role in neurological disorders in order to provide valuable insight into the potential therapeutic agents available for neurological disease treatment. However, most studies on mitophagy regulation are based on preclinical research using cell and animal models, which may not accurately reflect the effects in humans. This poses a challenge to the clinical application of drugs targeting mitophagy. Additionally, these drugs may carry the risk of intolerable side effects and toxicity. Future research should focus on the development of safer and more targeted drugs for mitophagy.

Review of PINK1-Parkin-mediated mitochondrial autophagy in Alzheimer's disease

Mitochondrial autophagy plays an important role in maintaining the complexity of mitochondrial functions and removing damaged mitochondria, of which the PINK1-Parkin signal pathway is one of the most classical pathways. Thus, a comprehensive and in-depth interpretation of the PINK1-Parkin signal pathway might deepen our understanding on the impacts of mitochondrial autophagy. Alzheimer's disease (AD) is a classical example of neurodegenerative disease. Research on the pathogenesis and treatments of AD has been a focus of scientific research because of its complexity and the limitations of current drug therapies. It was reported that the pathogenesis of AD might be related to mitochondrial autophagy due to excessive deposition of Aβ protein and aggravation of the phosphorylation of Tau protein. Two key proteins in the PINK1-Parkin signaling pathway, PINK1 and Parkin, have important roles in the folding and accumulation of Aβ protein and the phosphorylation of Tau protein. In addition, the intermediate signal molecules in the PINK1-Parkin signal pathway also have certain effects on AD. In this paper, we first described the role of PINK1-Parkin signal pathway on mitochondrial autophagy, then discussed and analyzed the effect of the PINK1-Parkin signal pathway in AD and other metabolic diseases. Our aim was to provide a theoretical direction to further elucidate the pathogenesis of AD and highlight the key molecules related to AD that could be important targets used for AD drug development.

Inflammatory signaling pathways in the treatment of Alzheimer's disease with inhibitors, natural products and metabolites (Review)

The intricate nature of Alzheimer's disease (AD) pathogenesis poses a persistent obstacle to drug development. In recent times, neuroinflammation has emerged as a crucial pathogenic mechanism of AD, and the targeting of inflammation has become a viable approach for the prevention and management of AD. The present study conducted a comprehensive review of the literature between October 2012 and October 2022, identifying a total of 96 references, encompassing 91 distinct pharmaceuticals that have been investigated for their potential impact on AD by inhibiting neuroinflammation. Research has shown that pharmaceuticals have the potential to ameliorate AD by reducing neuroinflammation mainly through regulating inflammatory signaling pathways such as NF‑κB, MAPK, NLRP3, PPARs, STAT3, CREB, PI3K/Akt, Nrf2 and their respective signaling pathways. Among them, tanshinone IIA has been extensively studied for its anti‑inflammatory effects, which have shown significant pharmacological properties and can be applied clinically. Thus, it may hold promise as an effective drug for the treatment of AD. The present review elucidated the inflammatory signaling pathways of pharmaceuticals that have been investigated for their therapeutic efficacy in AD and elucidates their underlying mechanisms. This underscores the auspicious potential of pharmaceuticals in ameliorating AD by impeding neuroinflammation.

Mitochondrial dysfunction and inflammasome activation in neurodegenerative diseases: Mechanisms and therapeutic implications

Impaired mitochondrial function is crucial to the pathogenesis of several neurodegenerative diseases. It causes the release of mitochondrial DNA (mtDNA), mitochondrial reactive oxygen species (mtROS), ATP, and cardiolipin, which activate the nucleotide-binding oligomerization domain (NOD)-like receptor protein 3 (NLRP3) inflammasome. NLRP3 inflammasome is an important innate immune system element contributing to neuroinflammation and neurodegeneration. Therefore, targeting the NLRP3 inflammasome has become an interesting therapeutic approach for treating neurodegenerative diseases. This review describes the role of mitochondrial abnormalities and over-activated inflammasomes in the progression of neurodegenerative diseases such as Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), Multiple sclerosis (MS), Amyotrophic lateral sclerosis (ALS), and Friedrich ataxia (FRDA). We also discuss the therapeutic strategies focusing on signaling pathways associated with inflammasome activation, which potentially alleviate neurodegenerative symptoms and impede disease progression.

Tetrahydroxy stilbene glycoside ameliorates neuroinflammation for Alzheimer's disease via cGAS-STING

Alzheimer's disease (AD), also known as senile dementia, is the most common degenerative disease of the central nervous system. Neuroinflammation is currently believed to be a crucial factor in the progression of AD, while its exact mechanism remains unclear. In this study, we demonstrated that AD transgenic mice exhibited cognitive deficits accompanied by the elevated serum and brain inflammation. Treating with a natural active ingredient tetrahydroxy stilbene glucoside (TSG) from the Chinese herb Polygonum multiflorum that has been well known for its unique anti-aging effect, learning-memory ability of AD mice was distinctly improved. Meanwhile, it was observed that the expressions of serum inflammatory cytokines and the activation of microglia in cerebral cortex and hippocampus were suppressed after TSG treatment, which was probably attributable to the decrease of cyclic GMP-AMP synthase (cGAS) and stimulator of interferon genes (STING) triggered immune response and NLRP3 inflammasome activation. Furthermore, cell culture experiments employing LPS combined with IFN-γ induced microglia activation showed that TSG reversed the polarization status of M1-type microglia to restore the quiescence, and cGAS-STING elevation was observed in the activated microglia and normalized by TSG incubation. In addition, TSG suppressed the production of inflammatory cytokines such as IL-1β, IL-6, TNF-α, IFN-α and IFN-β, as well as the expression of IFN regulatory proteins such as IFIT1 and IRF7 in the LPS/IFN-γ-stimulated inflammatory response in BV2 cell. Finally, it was also verified that TSG are, in part, through a cGAS-STING dependent pathway and triggered NLRP3 inflammasome activation to inhibit neuroinflammation through interfering with cGAS-STING inhibitors. Taken together, our findings highlight the health benefits of TSG and its potential application in preventing cognitive disorders by inhibiting neuroinflammation through cGAS-STING signaling pathway in AD.

Stilbenes, a Versatile Class of Natural Metabolites for Inflammation-An Overview

Stilbenes are polyphenolic allelochemicals synthesized by plants, especially grapes, peanuts, rhubarb, berries, etc., to defend themselves under stressful conditions. They are now exploited in medicine for their antioxidant, anti-proliferative and anti-inflammatory properties. Inflammation is the immune system's response to invading bacteria, toxic chemicals or even nutrient-deprived conditions. It is characterized by the release of cytokines which can wreak havoc on healthy tissues, worsening the disease condition. Stilbenes modulate NF-κB, MAPK and JAK/STAT pathways, and reduce the transcription of inflammatory factors which result in maintenance of homeostatic conditions. Resveratrol, the most studied stilbene, lowers the Michaelis constant of SIRT1, and occupies the substrate binding pocket. Gigantol interferes with the complement system. Besides these, oxyresveratrol, pterostilbene, polydatin, viniferins, etc., are front runners as drug candidates due to their diverse effects from different functional groups that affect bioavailability and molecular interactions. However, they each have different thresholds for toxicity to various cells of the human body, and thus a careful review of their properties must be conducted. In animal models of autoinflammatory diseases, the mode of application of stilbenes is important to their absorption and curative effects, as seen with topical and microemulsion gel methods. This review covers the diversity seen among stilbenes in the plant kingdom and their mechanism of action on the different inflammatory pathways. In detail, macrophages' contribution to inflamed conditions in the liver, the cardiac, connective and neural tissues, in the nephrons, intestine, lungs and in myriad other body cells is explored, along with detailed explanation on how stilbenes alleviate the symptoms specific to body site. A section on the bioavailability of stilbenes is included for understanding the limitations of the natural compounds as directly used drugs due to their rapid metabolism. Current delivery mechanisms include sulphonamides, or using specially designed synthetic drugs. It is hoped that further research may be fueled by this comprehensive work that makes a compelling argument for the exploitation of these compounds in medicine.

The Role of Mitochondrial Dysfunction in Alzheimer's: Molecular Defects and Mitophagy-Enhancing Approaches

Alzheimer's disease (AD), a progressive and chronic neurodegenerative syndrome, is categorized by cognitive and memory damage caused by the aggregations of abnormal proteins, specifically including Tau proteins and β-amyloid in brain tissue. Moreover, mitochondrial dysfunctions are the principal causes of AD, which is associated with mitophagy impairment. Investigations exploring pharmacological therapies alongside AD have explicitly concentrated on molecules accomplished in preventing/abolishing the gatherings of the abovementioned proteins and mitochondria damages. Mitophagy is the removal of dead mitochondria by the autophagy process. Damages in mitophagy, the manner of diversified mitochondrial degeneracy by autophagy resulting in an ongoing aggregation of malfunctioning mitochondria, were also suggested to support AD. Recently, plentiful reports have suggested a link between defective mitophagy and AD. This treaty highlights updated outlines of modern innovations and developments on mitophagy machinery dysfunctions in AD brains. Moreover, therapeutic and nanotherapeutic strategies targeting mitochondrial dysfunction are also presented in this review. Based on the significant role of diminished mitophagy in AD, we suggest that the application of different therapeutic approaches aimed at stimulating mitophagy in AD would be beneficial for targeting or reducing the mitochondrial dysfunction induced by AD.

Mitophagy in Alzheimer's disease: Molecular defects and therapeutic approaches

Mitochondrial dysfunctions are central players in Alzheimer's disease (AD). In addition, impairments in mitophagy, the process of selective mitochondrial degradation by autophagy leading to a gradual accumulation of defective mitochondria, have also been reported to occur in AD. We provide an updated overview of the recent discoveries and advancements on mitophagic molecular dysfunctions in AD-derived fluids and cells as well as in AD brains. We discuss studies using AD cellular and animal models that have unraveled the contribution of relevant AD-related proteins (Tau, Aβ, APP-derived fragments and APOE) in mitophagy failure. In accordance with the important role of impaired mitophagy in AD, we report on various therapeutic strategies aiming at stimulating mitophagy in AD and we summarize the benefits of these potential therapeutic strategies in human clinical trials.

Ac-YVAD-cmk ameliorated sevoflurane-induced cognitive dysfunction and revised mitophagy impairment

It is common for elderly patients to develop postoperative cognitive dysfunction (POCD), but the pathophysiological mechanisms have not yet been fully explored. NLRP3 inflammasome activation and mitophagy impairment was involved in neurodegenerative disease. This study investigated the interaction of NLRP3 inflammasome and mitophagy in sevoflurane-induced cognitive dysfunction. We found that sevoflurane induced cleaved caspase-1 level, IL-1β and IL-18 maturation, and activated NLRP3 inflammasome in aged mice and the primary hippocampus neuron. The cleaved caspase-1 was demonstrated in microglia of hippocampus. Ac-YVAD-cmk, a selected caspase-1 inhibitor, reduced the expression of cleaved caspase-1, IL-1β, IL-18 and NLRP3 inflammasome activation induced by sevoflurane. Ac-YVAD-cmk ameliorated learning ability impairment in aged mice induced by sevoflurane using Morris water maze. Moreover, Ac-YVAD-cmk reversed the mitophagy flux dysfunction induced by sevoflurane in aged mice by western blotting, immunostaining and mt-Keima reporters. For the first time, we found caspase-1 inhibitor mitigated mitochondria dysfunction and revised mitophagy impairment induced by sevoflurane.

Targeting autophagy process in center nervous trauma

The central nervous system (CNS) is the primary regulator of physiological activity, and when CNS is compromised, its physical functions are affected. Spinal cord injury (SCI) and traumatic brain injury (TBI) are common trauma in CNS that are difficult to recover from, with a higher global disability and mortality rate. Autophagy is familiar to almost all researchers due to its role in regulating the degradation and recycling of cellular defective or incorrect proteins and toxic components, maintaining body balance and regulating cell health and function. Emerging evidence suggests it has a broad and long-lasting impact on pathophysiological process such as oxidative stress, inflammation, apoptosis, and angiogenesis, involving the alteration of autophagy marker expression and function recovery. Changes in autophagy level are considered a potential therapeutic strategy and have shown promising results in preclinical studies for neuroprotection following traumatic brain injury. However, the relationship between upward or downward autophagy and functional recovery following SCI or TBI is debatable. This article reviews the regulation and role of autophagy in repairing CNS trauma and the intervention effects of autophagy-targeted therapeutic agents to find more and better treatment options for SCI and TBI patients.

Role of Mitophagy in neurodegenerative Diseases and potential tagarts for Therapy

Mitochondria dysfunction has been defined as one of the hallmarks of aging-related diseases as is characterized by the destroyed integrity, abnormal distribution and size, insufficient ATP supply, increased ROS production, and subsequently damage and oxidize the proteins, lipids and nucleic acid. Mitophagy, an efficient way of removing damaged or defective mitochondria by autophagy, plays a pivotal role in maintaining the mitochondrial quantity and quality control enabling the degradation of unwanted mitochondria, and thus rescues cellular homeostasis in response to stress. Accumulating evidence demonstrates that impaired mitophagy has been associated with many neurodegenerative diseases, such as Alzheimer's disease (AD), Parkinson's disease (PD) and Huntington's disease (HD), amyotrophic lateral sclerosis (ALS) in a variety of patients and disease models with neural death, oxidative stress and disturbed metabolism, either as the cause or consequence. These findings suggest that modulation of mitophagy may be considered as a valid therapeutic strategy in neurodegenerative diseases. In this review, we summarize recent findings on the mechanisms of mitophagy and its role in neurodegenerative diseases, with a particular focus on mitochondrial proteins acting as receptors that mediate mitophagy in these diseases.

Activating Parkin-dependent mitophagy alleviates oxidative stress, apoptosis, and promotes random-pattern skin flaps survival

The random-pattern skin flap is a crucial technique in reconstructive surgery and flap necrosis caused by ischemia/reperfusion injury is a major postoperative complication. Herein, we investigated the mechanism of mitophagy induced by Melatonin (ML) and its effect on the survival of skin flaps. Our results demonstrated that ML could activate mitophagy, ameliorate oxidative stress and alleviate apoptosis in Tert-Butyl hydroperoxide solution (TBHP)-stimulated human umbilical vein endothelial cells in vitro. Inhibiting ML-induced mitophagy considerably abolished its protective effects. Moreover, knockdown of Parkin by siRNA inhibited ML-induced mitophagy, and subsequently exacerbated oxidative stress and apoptosis. Further study demonstrated that inhibition of AMPK reversed these protective effects of ML and downregulated the expression of TFEB. In the vivo study, ML effectively promoted flap survival by activating mitophagy and subsequently ameliorating oxidative stress and mitigating apoptosis. These results established that ML is a potent agent capable for increasing random-pattern skin flap survival by activating Parkin-dependent mitophagy through the AMPK-TFEB signaling pathway.

Mitochondrial DNA Efflux Maintained in Gingival Fibroblasts of Patients with Periodontitis through ROS/mPTP Pathway

Mitochondria have their own mitochondrial DNA (mtDNA). Aberrant mtDNA is associated with inflammatory diseases. mtDNA is believed to induce inflammation via the abnormal mtDNA release. Periodontitis is an infectious, oral inflammatory disease. Human gingival fibroblasts (HGFs) from patients with chronic periodontitis (CP) have shown to generate higher reactive oxygen species (ROS) that cause oxidative stress and have decreased mtDNA copy number. Firstly, cell-free mtDNA was identified in plasma from CP mice through qRT-PCR. Next, we investigated whether mtDNA efflux was maintained in primary cultures of HGFs from CP patients and the possible underlying mechanisms using adenovirus-mediated transduction live cell imaging and qRT-PCR analysis. Here, we reported that mtDNA was increased in plasma from the CP mice. Additionally, we confirmed that CP HGFs had significant mtDNA efflux from mitochondria compared with healthy HGFs. Furthermore, lipopolysaccharide (LPS) from Porphyromonas gingivalis can also cause mtDNA release in healthy HGFs. Mechanistically, LPS upregulated ROS levels and mitochondrial permeability transition pore (mPTP) opening by inhibition of pyruvate dehydrogenase kinase (PDK)2 expression, resulting in mtDNA release. Importantly, mtDNA efflux was even persistent in HGFs after LPS was removed and cells were passaged to the next three generations, indicating that mtDNA abnormalities were retained in HGFs in vitro, similar to the primary hosts. Taken together, our results elucidate that mtDNA efflux was maintained in HGFs from periodontitis patients through abnormal ROS/mPTP activity. Therefore, our work indicates that persistent mtDNA efflux may be a possible diagnostic and therapeutic target for patients with periodontitis.

Pink1 promotes cell proliferation and affects glycolysis in breast cancer

Phosphatase and tensin homolog (PTEN)-induced kinase 1 (Pink1) is regarded as a tumor suppressor and plays an important role in cancer cell biology, while relatively few studies have examined Pink1 in breast cancer, especially in vivo. The aims of this study were to investigate Pink1 expression in different subtypes of breast cancer tissues and cell lines and explore the effect of Pink1 protein on breast cancer. In these experiments, Pink1 expression was investigated using the tissue microarray immunohistochemistry (TMA-IHC) method in 150 samples of breast cancer tissues with different subtypes, and strong staining of Pink1 was significantly correlated with the histological grade of breast cancer (p = 0.015). In addition, Pink1 messenger RNA (mRNA) displayed much higher expression levels in breast cancer cell lines than in MCF-10A breast epithelial cells. Moreover, proteomic data obtained by isobaric tags for relative and absolute quantification (iTRAQ) showed that Pink1 deletion induced a distinct proteomic profile in MDA-MB-231 cells, and enrichment analysis showed that the differential proteins were concentrated mainly in energy metabolism-related pathways. Moreover, Seahorse XF analysis showed that Pink1 knockout reduced the glycolytic ability of MDA-MB-231 cells. Our findings indicated that Pink1 may be an indicator of malignancy in breast cancer and that it presents oncogenic properties in breast cancer, which raises another perspective for understanding the regulatory role of Pink1 in breast cancer.

The Role of NLRP3 Inflammasome in Alzheimer’s Disease and Potential Therapeutic Targets

Alzheimer’s disease (AD) is a common age-related neurodegenerative disease characterized by progressive cognitive dysfunction and behavioral impairment. The typical pathological characteristics of AD are extracellular senile plaques composed of amyloid ß (Aβ) protein, intracellular neurofibrillary tangles formed by the hyperphosphorylation of the microtubule-associated protein tau, and neuron loss. In the past hundred years, although human beings have invested a lot of manpower, material and financial resources, there is no widely recognized drug for the effective prevention and clinical cure of AD in the world so far. Therefore, evaluating and exploring new drug targets for AD treatment is an important topic. At present, researchers have not stopped exploring the pathogenesis of AD, and the views on the pathogenic factors of AD are constantly changing. Multiple evidence have confirmed that chronic neuroinflammation plays a crucial role in the pathogenesis of AD. In the field of neuroinflammation, the nucleotide-binding oligomerization domain-like receptor pyrin domain-containing 3 (NLRP3) inflammasome is a key molecular link in the AD neuroinflammatory pathway. Under the stimulation of Aβ oligomers and tau aggregates, it can lead to the assembly and activation of NLRP3 inflammasome in microglia and astrocytes in the brain, thereby causing caspase-1 activation and the secretion of IL-1β and IL-18, which ultimately triggers the pathophysiological changes and cognitive decline of AD. In this review, we summarize current literatures on the activation of NLRP3 inflammasome and activation-related regulation mechanisms, and discuss its possible roles in the pathogenesis of AD. Moreover, focusing on the NLRP3 inflammasome and combining with the upstream and downstream signaling pathway-related molecules of NLRP3 inflammasome as targets, we review the pharmacologically related targets and various methods to alleviate neuroinflammation by regulating the activation of NLRP3 inflammasome, which provides new ideas for the treatment of AD.

Polygala saponins inhibit NLRP3 inflammasome-mediated neuroinflammation via SHP-2-Mediated mitophagy

Activation of the NLRP3 inflammasome and its mediated neuroinflammation are implicated in neurodegenerative diseases, while mitophagy negatively regulates NLRP3 inflammasome activation. SHP-2, a protein-tyrosine phosphatase, is critical for NLRP3 inflammasome regulation and inflammatory responses. In this study, we investigated whether triterpenoid saponins in Radix Polygalae inhibit the NLRP3 inflammasome via mitophagy induction. First, we isolated the active fraction (polygala saponins (PSS)) and identified 17 saponins by ultra-performance liquid chromatography coupled with diode-array detection and tandem quadrupole time-of-flight mass spectrometry (UHPLC-DAD-Q/TOF-MS). In microglial BV-2 cells, PSS induced mitophagy as evidenced by increased co-localization of LC3 and mitochondria, as well as an increased number of autophagic vacuoles surrounding the mitochondria. Furthermore, the mechanistic study found that PSS activated the AMPK/mTOR and PINK1/parkin signaling pathways via the upregulation of SHP-2. In Aβ(1-42)-, A53T-α-synuclein-, or Q74-induced BV-2 cells, PSS significantly inhibited NLRP3 inflammasome activation, which was attenuated by bafilomycin A1 (an autophagy inhibitor) and SHP099 (an SHP-2 inhibitor). In addition, the co-localization of LC3 and ASC revealed that PSS promoted the autophagic degradation of the NLRP3 inflammasome. Moreover, PSS decreased apoptosis in conditioned medium-induced PC-12 cells. In APP/PS1 mice, PSS improved cognitive function, ameliorated Aβ pathology, and inhibited neuronal death. Collectively, the present study, for the first time, shows that PSS inhibit the NLRP3 inflammasome via SHP-2-mediated mitophagy in vitro and in vivo, which strongly suggests the therapeutic potential of PSS in various neurodegenerative diseases.

A Review of Pharmacology, Toxicity and Pharmacokinetics of 2,3,5,4'-Tetrahydroxystilbene-2-O-β-D-Glucoside

Polygonum multiflorum Thunb. (He-shou-wu in Chinese), a Chinese botanical drug with a long history, is widely used to treat a variety of chronic diseases in clinic, and has been given the reputation of “rejuvenating and prolonging life” in many places. 2,3,4′,5-tetrahydroxystilbene-2-O-β-D-glucoside (TSG, C₂₀H₂₂O₉) is the main and unique active ingredient isolated from Polygonum multiflorum Thunb., which has extensive pharmacological activities. Modern pharmacological studies have confirmed that TSG exhibits significant activities in treating various diseases, including inflammatory diseases, neurodegenerative diseases, cardiovascular diseases, hepatic steatosis, osteoporosis, depression and diabetic nephropathy. Therefore, this review comprehensively summarizes the pharmacological and pharmacokinetic properties of TSG up to 2021 by searching the databases of Web of Science, PubMed, ScienceDirect and CNKI. According to the data, TSG shows remarkable anti-inflammation, antioxidation, neuroprotection, cardiovascular protection, hepatoprotection, anti-osteoporosis, enhancement of memory and anti-aging activities through regulating multiple molecular mechanisms, such as NF-κB, AMPK, PI3K-AKT, JNK, ROS-NO, Bcl-2/Bax/Caspase-3, ERK1/2, TGF-β/Smad, Nrf2, eNOS/NO and SIRT1. In addition, the toxicity and pharmacokinetics of TSG are also discussed in this review, which provided direction and basis for the further development and clinical application of TSG.

Alliin alleviates LPS-induced pyroptosis via promoting mitophagy in THP-1 macrophages and mice

Pyroptosis is a new type of programmed cell death associated with inflammation. Excessive pyroptosis can cause body damage. Alliin is an organosulfur compound extracted from garlic, bearing anti-oxidation and anti-inflammatory properties. In this study, we revealed that alliin alleviated LPS-induced macrophage pyroptosis by detecting PI staining, IL-1β and IL-18 release in vitro and in vivo. In the study of mechanism, we found that alliin might reduce the activation of NLRP3 inflammosome by decreasing intracellular ROS generation. Subsequently, we detected the effect of alliin on mitophagy which degraded damaged mitochondria. The results showed that alliin promoted PINK 1/Parkin-mediated mitophagy. After adding the mitophagy inhibitor CsA, the alleviating effect of alliin on mitochondrial damage and mitochondrial ROS were reversed and the relieving effect of alliin on LPS-induced pyroptosis was inhibited. These results suggested that alliin might reduce intracellular ROS production by promoting mitophagy, thus alleviating LPS-induced macrophages pyroptosis. Our study provides a new perspective and theoretical basis for alliin to alleviate pyroptosis which could further induce body damage.

Pharmacological modulation of autophagy for Alzheimer’s disease therapy: Opportunities and obstacles

Alzheimer's disease (AD) is a prevalent and deleterious neurodegenerative disorder characterized by an irreversible and progressive impairment of cognitive abilities as well as the formation of amyloid β (Aβ) plaques and neurofibrillary tangles (NFTs) in the brain. By far, the precise mechanisms of AD are not fully understood and no interventions are available to effectively slow down progression of the disease. Autophagy is a conserved degradation pathway that is crucial to maintain cellular homeostasis by targeting damaged organelles, pathogens, and disease-prone protein aggregates to lysosome for degradation. Emerging evidence suggests dysfunctional autophagy clearance pathway as a potential cellular mechanism underlying the pathogenesis of AD in affected neurons. Here we summarize the current evidence for autophagy dysfunction in the pathophysiology of AD and discuss the role of autophagy in the regulation of AD-related protein degradation and neuroinflammation in neurons and glial cells. Finally, we review the autophagy modulators reported in the treatment of AD models and discuss the obstacles and opportunities for potential clinical application of the novel autophagy activators for AD therapy.

Neuroprotective effects of tetrahydroxystilbene glucoside against rotenone-induced toxicity in PC12 cells

To investigate the mechanism of the protective effect of tetrahydroxystilbene glucoside (TSG) on nerve cells, an injury model induced by rotenone in PC12 cells was constructed. Cell viability was detected by using CCK8 assay. Apoptosis was detected by using flow cytometry. The mitochondrial membrane potential (MMP) was detected by using the fluorescent probe JC-1. Generation of reactive oxygen species (ROS) in PC12 cells was determined using the CM-H₂DCFDA probe. Protein expression in PC12 cells was detected using western blotting. The results showed that TSG (20-100 μM) attenuated the cytotoxic effects of rotenone on PC12 cells. TSG pretreatment attenuated the apoptosis rate, the degradation of PARP and the activation of cleaved caspase 3, which was induced by rotenone. TSG can significantly reduce the effect of rotenone on the reduction of MMP and the expression of cytoC in the cytosolic fraction. TSG attenuated rotenone-induced de-phosphorylation and mitochondrial translocation of cofilin, as well as rotenone-induced accumulation of ROS. The western blot results showed that ROT could decrease the expression level of p-GSK-3β and p-AKT, and TSG could weaken these effects of rotenone. In addition, TSG increased the expression level of Nrf2 in the nuclear fraction. These results suggest that TSG could protect PC12 cells against rotenone through multiple pathways. Thus, TSG has the potential to become a novel neuroprotective agent.

Insights Into Parkin-Mediated Mitophagy in Alzheimer's Disease: A Systematic Review

Background: Parkin-mediated mitophagy is the dominant mitophagy pathway of neural cells. Its restoration will result in prevention of cognitive decline, including Alzheimer's disease (AD). The role of this mitophagy pathway in neurodegenerative diseases has drawn attention in recent years. The two main pathological proteins in AD, amyloid β (Aβ) and human Tau (hTau), interfere with mitochondrial dynamics through several pathways. However, taking into consideration the specific interactions between Aβ/hTau and Parkin, special focus is required on this mitophagy pathway and AD. In this review, these interactions are fully discussed, and an overview of the neuroprotective drugs that enhance Parkin-mediated mitophagy is presented. Methods: This systematic review was performed according to PRISMA guidelines, and a comprehensive literature search was done in the electronic databases up to September 2020, using search terms in the titles and abstracts to identify relevant studies. One hundred eighty-six articles were found, and 113 articles were screened by title and abstract. Finally, 25 articles were included in this systematic review according to our inclusion and exclusion criteria. Results: Accumulation of Aβ and hTau affects mitophagy, including Parkin-mediated. Tau seems to prevent Parkin translocation directly. A Parkin level in the cell appears to be of importance in determining the damage caused by Aβ and hTau and in the future therapeutic approaches. Parkin controls the PINK1 level via the presenillins, suggesting that mutations in presenillins affect Parkin mitophagy. Significance: Parkin mitophagy is a process affected by several AD pathological events multidimensionally.

Activation of NLRP3 Inflammasome and Onset of Alzheimer's Disease

The nucleotide-binding domain leucine-rich repeat and pyrin domain containing receptor protein 3 (NLRP3) is an important pattern recognition receptor in human innate immunity. Activation of the NLRP3 inflammasome play a key role in the pathogenesis of Alzheimer’s disease (AD). Theories explaining activation of the NLRP3 inflammasome include the reactive oxygen species theory, the lysosomal damage theory and the mitochondrial DNA theory. The NLRP3 activation promotes occurrence of AD by producing IL-1β, IL-18 and other cytokines, and then by affecting the deposition of Aβ and tau proteins. Over-activated NLRP3 inflammasome often impair cell function and induces immune-related diseases. Some mechanisms have been found to negatively regulate activation of the NLRP3 inflammasome, which may be through receptor binding blocking mechanism, autophagy related mechanism, abnormal cytokine secretion mechanism, or interference related gene expression regulation mechanism. In this review, we summarize the possible mechanisms by which the activation of NLRP3 inflammasomes affects the pathogenesis of AD, and the recent advances in the prevention and treatment of AD by controlling the activation of NLRP3 inflammasomes. By researching the activation or inactivation of NLRP3 inflammasome, it is possible to reveal the pathogenesis of AD from a new perspective and provide a new idea for the prevention and treatment of AD.

Fingerprinting and Determination of Hepatotoxic Constituents in Polygoni Multiflori Radix Praeparata of Different Producing Places by HPLC

Polygoni Multiflori Radix Praeparata (PMRP) is used as Chinese herbal medicine with long history. However, reports about PMRP hepatotoxicity have increased recently, and producing area might be one reason. This article aims to figure out the relationship between producing area and hepatotoxic ingredients in PMRP. HPLC fingerprint for PMRP was established and the contents of gallic acid, trans-stilbene glycoside (TSG), emodin-8-O-β-D-glucoside (EG), emodin and physcion were determined. Clustering heatmap was implemented by TCMNPAS software，and principal component analysis was implemented by SPSS and SIMCA-P software. Hepatotoxic constituents' contents of PMRP from separate producing area were different. PMRP from Guangxi had the highest content of gallic acid, TSG, EG, emodin and physcion, followed by Hubei, Guangdong, Guizhou, Yunnan. PMRP from Henan had the lowest contents of hepatotoxic components. Hepatotoxic components' contents of PMRP in southern were higher than central China. This study carried out a preliminary qualitative and quantitative investigation on the PMRP from different producing places, which provided a basis for safe medication of PMRP.

Natural products as pharmacological modulators of mitochondrial dysfunctions for the treatments of Alzheimer's disease: A comprehensive review

Alzheimer's disease (AD) is the most common progressive neurodegenerative disorder characterized by neuronal loss and cognitive impairment that harshly affect the elderly individuals. Currently, the available anti-AD pharmacological approaches are purely symptomatic to alleviate AD symptoms, and the curative effects of novel anti-AD drugs focused on Aβ target are disappointing. Hence, there is a tremendous need to adjust AD therapeutic targets and discover novel anti-AD agents. In AD, mitochondrial dysfunction gradually triggers neuronal death from different aspects and worsens the occurrence and progress of AD. Consequently, it has been proposed that the intervention of impaired mitochondria represents an attractive breakthrough point for AD treatments. Due to chemical diversity, poly-pharmacological activities, few adverse effects and multiple targeting, natural products (NPs) have been identified as a valuable treasure for drug discovery and development. Multiple lines of studies have scientifically proven that NPs display ameliorative benefits in AD treatment in relation to mitochondrial dysfunction. This review surveys the complicated implications for mitochondrial dysregulation and AD, and then summarizes the potentials of NPs and their underlying molecular mechanisms against AD via reducing or improving mitochondrial dysfunction. It is expected that this work may open the window to speed up the development of innovative anti-AD drugs originated from NPs and improve upcoming AD therapeutics.

Inflammasome and Mitophagy Connection in Health and Disease

The inflammasome is a large intracellular protein complex that activates inflammatory caspase-1 and induces the maturation of interleukin (IL)-1β and IL-18. Mitophagy plays an essential role in the maintenance of mitochondrial homeostasis during stress. Previous studies have indicated compelling evidence of the crosstalk between inflammasome and mitophagy. Mitophagy regulation of the inflammasome, or vice versa, is crucial for various biological functions, such as controlling inflammation and metabolism, immune and anti-tumor responses, and pyroptotic cell death. Uncontrolled regulation of the inflammasome often results in pathological inflammation and pyroptosis, and causes a variety of human diseases, including metabolic and inflammatory diseases, infection, and cancer. Here, we discuss how improved understanding of the interactions between inflammasome and mitophagy can lead to novel therapies against various disease pathologies, and how the inflammasome-mitophagy connection is currently being targeted pharmacologically by diverse agents and small molecules. A deeper understanding of the inflammasome-mitophagy connection will provide new insights into human health and disease through the balance between mitochondrial clearance and pathology.