Anti-Na+/K+-ATPase immunotherapy ameliorates α-synuclein pathology through activation of Na+/K+-ATPase α1-dependent autophagy

Na+/K+-ATPase: ion pump, signal transducer, or cytoprotective protein, and novel biological functions

Na+/K+-ATPase is a transmembrane protein that has important roles in the maintenance of electrochemical gradients across cell membranes by transporting three Na+ out of and two K+ into cells. Additionally, Na+/K+-ATPase participates in Ca2+-signaling transduction and neurotransmitter release by coordinating the ion concentration gradient across the cell membrane. Na+/K+-ATPase works synergistically with multiple ion channels in the cell membrane to form a dynamic network of ion homeostatic regulation and affects cellular communication by regulating chemical signals and the ion balance among different types of cells. Therefore, it is not surprising that Na+/K+-ATPase dysfunction has emerged as a risk factor for a variety of neurological diseases. However, published studies have so far only elucidated the important roles of Na+/K+-ATPase dysfunction in disease development, and we are lacking detailed mechanisms to clarify how Na+/K+-ATPase affects cell function. Our recent studies revealed that membrane loss of Na+/K+-ATPase is a key mechanism in many neurological disorders, particularly stroke and Parkinson's disease. Stabilization of plasma membrane Na+/K+-ATPase with an antibody is a novel strategy to treat these diseases. For this reason, Na+/K+-ATPase acts not only as a simple ion pump but also as a sensor/regulator or cytoprotective protein, participating in signal transduction such as neuronal autophagy and apoptosis, and glial cell migration. Thus, the present review attempts to summarize the novel biological functions of Na+/K+-ATPase and Na+/K+-ATPase-related pathogenesis. The potential for novel strategies to treat Na+/K+-ATPase-related brain diseases will also be discussed.

Toxic mechanisms of nanoplastics exposure at environmental concentrations on juvenile red swamp crayfish (Procambarus clarkii): From multiple perspectives

Nanoplastics pollution has emerged as a global issue due to its widespread potential toxicity. This study delved in to toxic effects of nanoplastics on juvenile P. clarkii and molecular mechanisms from perspectives of growth, biochemical, histopathological analysis and transcriptome level for the first time. The findings of this study indicated that nanoplastics of different concentrations have varying influence mechanisms on juvenile P. clarkii. Nanoplastics have inhibitory effects on growth of juvenile P. clarkii, can induce oxidative stress. The biochemical analysis and transcriptome results indicated that 10 mg/L nanoplastics can activate the antioxidant defense system and non-specific immune system in juvenile P. clarkii, and affect energy metabolism and oxidative phosphorylation. While 20 mg/L and 40 mg/L have a destructive influence on the immune function in juvenile P. clarkii, leading to lipid peroxidation and oxidative damage, and induce apoptosis, can affect ion transport and osmotic pressure regulation. The findings of this study can offer foundational data for delving further into impacts of nanoplastics on crustaceans and toxicity mechanism.

JWA binding to NCOA4 alleviates degeneration in dopaminergic neurons through suppression of ferritinophagy in Parkinson's disease

Parkinson's disease (PD) poses a significant challenge in neurodegenerative disorders, characterized by the progressive loss of dopaminergic (DA) neurons in the substantia nigra pars compacta (SNc). The intricate mechanisms orchestrating DA neurodegeneration in PD are not fully understood, necessitating the exploration of innovative therapeutic approaches. Recent studies have implicated ferroptosis as a major contributor to the loss of DA neurons, revealing a complex interplay between iron accumulation and neurodegeneration. However, the sophisticated nature of this process challenges the conventional belief that mere iron removal could effectively prevent DA neuronal ferroptosis. Here, we report JWA, alternatively referred to as ARL6IP5, as a negative regulator of ferroptosis, capable of ameliorating DA neuronal loss in the context of PD. In this study, synchronized expression patterns of JWA and tyrosine hydroxylase (TH) in PD patients and mice were observed, underscoring the importance of JWA for DA neuronal survival. Screening of ferroptosis-related genes unraveled the engagement of iron metabolism in the JWA-dependent inhibition of DA neuronal ferroptosis. Genetic manipulation of JWA provided compelling evidence linking its neuroprotective effects to the attenuation of NCOA4-mediated ferritinophagy. Molecular docking, co-immunoprecipitation, and immunofluorescence studies confirmed that JWA mitigated DA neuronal ferroptosis by occupying the ferritin binding site of NCOA4. Moreover, the JWA-activating compound, JAC4, demonstrated promising neuroprotective effects in cellular and animal PD models by elevating JWA expression, offering a potential avenue for neuroprotection in PD. Collectively, our work establishes JWA as a novel regulator of ferritinophagy, presenting a promising therapeutic target for addressing DA neuronal ferroptosis in PD.

Vagus nerve stimulation as a promising neuroprotection for ischemic stroke via α7nAchR-dependent inactivation of microglial NLRP3 inflammasome

Ischemic stroke is a major cause of disability and death worldwide, and its management requires urgent attention. Previous studies have shown that vagus nerve stimulation (VNS) exerts neuroprotection in ischemic stroke by inhibiting neuroinflammation and apoptosis. In this study, we evaluated the timing for VNS intervention in ischemic stroke, and the underlying mechanisms  of VNS-induced neuroprotection. Mice were subjected to transient middle cerebral artery occlusion (tMCAO) for 60 min. The left vagus nerve at cervical level was exposed and attached to an electrode connected to a low-frequency electrical stimulator. Vagus nerve stimulation (VNS) was given for 60 min before, during and after tMCAO (Pre-VNS, Dur-VNS, Post-VNS). Neurological function was assessed 24 h after reperfusion. We found that all the three VNS significantly protected against the tMCAO-induced injury evidenced by improved neurological function and reduced infarct volume. Moreover, the Pre-VNS was the most effective against the ischemic injury. We found that tMCAO activated microglia in the ischemic core and penumbra regions of the brain, followed by the NLRP3 inflammasome activation-induced neuroinflammation, which finally triggered neuronal death. VNS treatment preserved α7nAChR expression in the penumbra regions, inhibited NLRP3 inflammasome activation and ensuing neuroinflammation, rescuing cerebral neurons. The role of α7nAChR in microglial NLRP3 inflammasome activation in ischemic stroke was further validated using genetic manipulations, including Chrna7 knockout mice and microglial Chrna7 overexpression mice, as well as pharmacological interventions using the α7nAChR inhibitor methyllycaconitine and agonist PNU-282987. Collectively, this study demonstrates the potential of VNS as a safe and effective strategy to treat ischemic stroke, and presents a new approach targeting microglial NLRP3 inflammasome, which might be therapeutic for other inflammation-related diseases.

Targeting NKAα1 to treat Parkinson's disease through inhibition of mitophagy-dependent ferroptosis

Dysfunction of the Na+/K+-ATPase (NKA) has been documented in various neurodegenerative diseases, yet the specific role of NKAα1 in Parkinson's disease (PD) remains incompletely understood. In this investigation, we utilized NKAα1 haploinsufficiency (NKAα1+/-) mice to probe the influence of NKAα1 on dopaminergic (DA) neurodegeneration induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Our findings reveal that NKAα1+/- mice displayed a heightened loss of DA neurons and more pronounced motor dysfunction compared to the control group when exposed to MPTP. Intriguingly, this phenomenon coincided with the activation of ferroptosis and impaired mitophagy both in vivo and in vitro. To scrutinize the role and underlying mechanism of NKAα1 in PD, we employed DR-Ab, an antibody targeting the DR-region of the NKA α subunit. Our study demonstrates that the administration of DR-Ab effectively reinstated the membrane abundance of NKAα1, thereby mitigating MPTP-induced DA neuron loss and subsequent improvement in behavioral deficit. Mechanistically, DR-Ab heightened the formation of the surface NKAα1/SLC7A11 complex, inhibiting SLC7A11-dependent ferroptosis. Moreover, DR-Ab disrupted the cytosolic interaction between NKAα1 and Parkin, facilitating the translocation of Parkin to mitochondria and enhancing the process of mitophagy. In conclusion, this study establishes NKAα1 as a key regulator of ferroptosis and mitophagy, identifying its DR-region as a promising therapeutic target for PD.

Disruption of the Na+/K+-ATPase-purinergic P2X7 receptor complex in microglia promotes stress-induced anxiety

Na+/K+-ATPase (NKA) plays an important role in the central nervous system. However, little is known about its function in the microglia. Here, we found that NKAα1 forms a complex with the purinergic P2X7 receptor (P2X7R), an adenosine 5'-triphosphate (ATP)-gated ion channel, under physiological conditions. Chronic stress or treatment with lipopolysaccharide plus ATP decreased the membrane expression of NKAα1 in microglia, facilitated P2X7R function, and promoted microglia inflammatory activation via activation of the NLRP3 inflammasome. Accordingly, global deletion or conditional deletion of NKAα1 in microglia under chronic stress-induced aggravated anxiety-like behavior and neuronal hyperexcitability. DR5-12D, a monoclonal antibody that stabilizes membrane NKAα1, improved stress-induced anxiety-like behavior and ameliorated neuronal hyperexcitability and neurogenesis deficits in the ventral hippocampus of mice. Our results reveal that NKAα1 limits microglia inflammation and may provide a target for the treatment of stress-related neuroinflammation and diseases.

Deleting IP6K1 stabilizes neuronal sodium-potassium pumps and suppresses excitability

Inositol pyrophosphates are key signaling molecules that regulate diverse neurobiological processes. We previously reported that the inositol pyrophosphate 5-InsP7, generated by inositol hexakisphosphate kinase 1 (IP6K1), governs the degradation of Na+/K+-ATPase (NKA) via an autoinhibitory domain of PI3K p85α. NKA is required for maintaining electrochemical gradients for proper neuronal firing. Here we characterized the electrophysiology of IP6K1 knockout (KO) neurons to further expand upon the functions of IP6K1-regulated control of NKA stability. We found that IP6K1 KO neurons have a lower frequency of action potentials and a specific deepening of the afterhyperpolarization phase. Our results demonstrate that deleting IP6K1 suppresses neuronal excitability, which is consistent with hyperpolarization due to an enrichment of NKA. Given that impaired NKA function contributes to the pathophysiology of various neurological diseases, including hyperexcitability in epilepsy, our findings may have therapeutic implications.

Caprin-1 influences autophagy-induced tumor growth and immune modulation in pancreatic cancer

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is characterized by rapid progression and poor prognosis. Understanding the genetic mechanisms that affect cancer properties and reprogram tumor immune microenvironment will develop new strategies to maximize the benefits for cancer therapies.

METHODS

Gene signatures and biological processes associated with advanced cancer and unfavorable outcome were profiled using bulk RNA sequencing and spatial transcriptome sequencing, Caprin-1 was identified as an oncogenesis to expedite pancreatic cancer growth by activating autophagy. The mechanism of Caprin-1 inducing autophagy activation was further explored in vitro and in vivo. In addition, higher level of Caprin-1 was found to manipulate immune responses and inflammatory-related pathways. The immune profiles associated with increased levels of Caprin-1 were identified in human PDAC samples. The roles of CD4+T cells, CD8+T cells and tumor associated macrophages (TAMs) on clinical outcomes prediction were investigated.

RESULTS

Caprin-1 was significantly upregulated in advanced PDAC and correlated with poor prognosis. Caprin-1 interacted with both ULK1 and STK38, and manipulated ULK1 phosphorylation which activated autophagy and exerted pro-tumorigenic phenotypes. Additionally, the infiltrated CD4+T cells and tumor associated macrophages (TAMs) were increased in Caprin-1High tissues. The extensive CD4+T cells determined poor clinical outcome in Caprin-1high patients, arguing that highly expressed Caprin-1 may assist cancer cells to escape from immune surveillance.

CONCLUSIONS

Our findings establish causal links between the upregulated expression of Caprin-1 and autophagy activation, which may manipulate immune responses in PDAC development. Our study provides insights into considering Caprin-1 as potential therapeutic target for PDAC treatment.

Purple pitanga extract (Eugenia uniflora) attenuates oxidative stress induced by MPTP

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) has been widely used due to its specific and reproducible neurotoxic effect on the nigrostriatal system, being considered a convenient model of dopaminergic neurodegeneration to study interventions therapeutics. The purple pitanga (Eugenia uniflora) is a polyphenol-rich fruit with antioxidant and antidepressant properties, among others. Therefore, this study investigated the effect of purple pitanga extract (PPE) on acute early oxidative stress induced by intranasal 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) administration in rats. Male Wistar rats were pre-treated orally with PPE (1000 mg/kg) or vehicle. After 24 h, MPTP (0.1 mg/10µL/nostril) or vehicle was administered bilaterally into the animal's nostrils, and 6 h later, the olfactory bulb (OB), striatum (ST), and substantia nigra (SN) were collected to evaluate the oxidative stress parameters. Our findings revealed that OB and SN were the most affected areas after 6 h of MPTP infusion; an early increase in reactive oxygen species (ROS) levels was observed, while pretreatment with a single dose of PPE prevented this increment. No differences in thiobarbituric acid reactive species (TBARS) and 3-nitrotyrosine (3-NT) formation were observed, although 4-hydroxy-2-nonenal (4-HNE) levels increased, which is the most toxic form of lipid peroxidation, in the MPTP group. The PPE pretreatment could prevent this increase by increasing the NPSH levels previously decreased by MPTP. Furthermore, PPE prevents the Na+/K + ATPase strongly inhibited by MPTP, showing the neuroprotective capacity of the PPE by inhibiting the MPTP-generated oxidation. Thus, we demonstrated for the first time the antioxidant and neuroprotective effects of PPE against the early MPTP neurotoxicity.

Targeting the Na+/K+ ATPase DR-region with DR-Ab improves doxorubicin-induced cardiotoxicity

Doxorubicin (DOX) is a potent chemotherapeutic drug for various cancers. Yet, the cardiotoxic side effects limit its application in clinical uses, in which ferroptosis serves as a crucial pathological mechanism in DOX-induced cardiotoxicity (DIC). A reduction of Na+/K + ATPase (NKA) activity is closely associated with DIC progression. However, whether abnormal NKA function was involved in DOX-induced cardiotoxicity and ferroptosis remains unknown. Here, we aim to decipher the cellular and molecular mechanisms of dysfunctional NKA in DOX-induced ferroptosis and investigate NKA as a potential therapeutic target for DIC. A decrease activity of NKA further aggravated DOX-triggered cardiac dysfunction and ferroptosis in NKAα1 haploinsufficiency mice. In contrast, antibodies against the DR-region of NKAα-subunit (DR-Ab) attenuated the cardiac dysfunction and ferroptosis induced by DOX. Mechanistically, NKAα1 interacted with SLC7A11 to form a novel protein complex, which was directly implicated in the disease progression of DIC. Furthermore, the therapeutic effect of DR-Ab on DIC was mediated by reducing ferroptosis by promoting the association of NKAα1/SLC7A11 complex and maintaining the stability of SLC7A11 on the cell surface. These results indicate that antibodies targeting the DR-region of NKA may serve as a novel therapeutic strategy to alleviate DOX-induced cardiotoxicity.

Anti-Na+/K+-ATPase DR antibody attenuates UUO-induced renal fibrosis through inhibition of Na+/K+-ATPase α1-dependent HMGB1 release

Reduced Na⁺/K⁺-ATPase (NKA) activity and NKAα1 expression are engaged in the pathologies of renal diseases. NKA-mediated Src activation is not the only reason for NKA-related renal fibrosis. In this study, we found that genetic reduction of NKAα1 exhibited exacerbated tubulointerstitial lesions and fibrosis in the UUO mice model. Activation of NKAα1 with an antibody against the extracellular DR region of the NKAα1 subunit (DRm217) prevented UUO-induced tubulointerstitial lesions, preserved kidney function, and decrease renal fibrosis. Further studies revealed that NKAα1 deficiency mice exhibited high inflammation factors expression when they suffered UUO surgery, compared with NKAα1^+/+ (WT) mice. DRm217 alleviated inflammatory cell infiltration, suppress NF-κB phosphorylation, and decreased inflammatory factors expression in the UUO mice model. Released HMGB1 can trigger the inflammatory response and contribute to renal fibrosis. Knockdown of NKA in renal tubular cells or in NKAα1^+/- mice was associated with more susceptibility to HMGB1 release in the UUO mice model. DRm217 exerted its antifibrotic effect via inhibiting HMGB1 release. Furthermore, AMPK activation participates in the effect of DRm217 on inhibiting HMGB1 release. Our findings suggest that NKAα1 is a regulator of renal fibrosis and its DR-region is a novel target on it.

An update on the molecular mechanism and pharmacological interventions for Ischemia-reperfusion injury by regulating AMPK/mTOR signaling pathway in autophagy

AMP-activated protein kinase (5'-adenosine monophosphate-activated protein kinase, AMPK)/mammalian target of rapamycin (mTOR) is an important signaling pathway maintaining normal cell function and homeostasis in vivo. The AMPK/mTOR pathway regulates cellular proliferation, autophagy, and apoptosis. Ischemia-reperfusion injury (IRI) is secondary damage that frequently occurs clinically in various disease processes and treatments, and the exacerbated injury during tissue reperfusion increases disease-associated morbidity and mortality. IRI arises from multiple complex pathological mechanisms, among which cell autophagy is a focus of recent research and a new therapeutic target. The activation of AMPK/mTOR signaling in IRI can modulate cellular metabolism and regulate cell proliferation and immune cell differentiation by adjusting gene transcription and protein synthesis. Thus, the AMPK/mTOR signaling pathway has been intensively investigated in studies focused on IRI prevention and treatment. In recent years, AMPK/mTOR pathway-mediated autophagy has been found to play a crucial role in IRI treatment. This article aims to elaborate the action mechanisms of AMPK/mTOR signaling pathway activation in IRI and summarize the progress of AMPK/mTOR-mediated autophagy research in the field of IRI therapy.

Therapeutic modulation of JAK-STAT, mTOR, and PPAR-γ signaling in neurological dysfunctions

The cytokine-activated Janus kinase (JAK)-signal transducer and activator of transcription (STAT) cascade is a pleiotropic pathway that involves receptor subunit multimerization. The mammalian target of rapamycin (mTOR) is a ubiquitously expressed serine-threonine kinase that perceives and integrates a variety of intracellular and environmental stimuli to regulate essential activities such as cell development and metabolism. Peroxisome proliferator-activated receptor-gamma (PPARγ) is a prototypical metabolic nuclear receptor involved in neural differentiation and axon polarity. The JAK-STAT, mTOR, and PPARγ signaling pathways serve as a highly conserved signaling hub that coordinates neuronal activity and brain development. Additionally, overactivation of JAK/STAT, mTOR, and inhibition of PPARγ signaling have been linked to various neurocomplications, including neuroinflammation, apoptosis, and oxidative stress. Emerging research suggests that even minor disruptions in these cellular and molecular processes can have significant consequences manifested as neurological and neuropsychiatric diseases. Of interest, target modulators have been proven to alleviate neuronal complications associated with acute and chronic neurological deficits. This research-based review explores the therapeutic role of JAK-STAT, mTOR, and PPARγ signaling modulators in preventing neuronal dysfunctions in preclinical and clinical investigations.

Recent Advances in the Study of Na+/K+-ATPase in Neurodegenerative Diseases

Na⁺/K⁺-ATPase (NKA), a large transmembrane protein, is expressed in the plasma membrane of most eukaryotic cells. It maintains resting membrane potential, cell volume and secondary transcellular transport of other ions and neurotransmitters. NKA consumes about half of the ATP molecules in the brain, which makes NKA highly sensitive to energy deficiency. Neurodegenerative diseases (NDDs) are a group of diseases characterized by chronic, progressive and irreversible neuronal loss in specific brain areas. The pathogenesis of NDDs is sophisticated, involving protein misfolding and aggregation, mitochondrial dysfunction and oxidative stress. The protective effect of NKA against NDDs has been emerging gradually in the past few decades. Hence, understanding the role of NKA in NDDs is critical for elucidating the underlying pathophysiology of NDDs and identifying new therapeutic targets. The present review focuses on the recent progress involving different aspects of NKA in cellular homeostasis to present in-depth understanding of this unique protein. Moreover, the essential roles of NKA in NDDs are discussed to provide a platform and bright future for the improvement of clinical research in NDDs.

Neuroprotective Mechanism of Icariin on Hypoxic Ischemic Brain Damage in Neonatal Mice

Objective. Our previous results showed that icariin (ICA) could inhibit apoptosis and provide neuroprotection against hypoxic-ischemic brain damage (HIBD) in neonatal mice, but the specific mechanism of its neuroprotective effect remains unknown. This study aims at exploring whether ICA plays a neuroprotective role in apoptosis inhibition by regulating autophagy through the estrogen receptor α (ERα)/estrogen receptor β (ERβ) pathway in neonatal mice with HIBD. Methods. A neonatal mouse model of HIBD was constructed in vivo, and an oxygen and glucose deprivation (OGD) model in HT22 cells from the hippocampal neuronal system was constructed in vitro. The effects of ICA pretreatment on autophagy and the expression of ERα and ERβ were detected in vitro and in vivo, respectively. ICA pretreatment was also supplemented with the autophagy inhibitor 3-methyladenine (3-MA), ERα inhibitor methylpiperidino pyrazole (MPP), and ERβ inhibitor 4-(2-phenyl-5,7-bis (trifluoromethyl) pyrazolo [1,5-a] pyramidin-3-yl) phenol (PHTPP) to further detect whether ICA pretreatment can activate the ERα/ERβ pathway to promote autophagy and reduce HIBD-induced apoptosis to play a neuroprotective role against HIBD in neonatal mice. Results. ICA pretreatment significantly promoted autophagy in HIBD mice. Treatment with 3-MA significantly inhibited the increase in autophagy induced by ICA pretreatment, reversed the neuroprotective effect of ICA pretreatment, and promoted apoptosis. Moreover, ICA pretreatment significantly increased the expression levels of the ERα and ERβ proteins in HIBD newborn mice. Both MPP and PHTPP administration significantly inhibited the expression levels of the ERα and ERβ proteins activated by ICA pretreatment, reversed the neuroprotective effects of ICA pretreatment, inhibited the increase in autophagy induced by ICA pretreatment, and promoted apoptosis. Conclusion. ICA pretreatment may promote autophagy by activating the ERα and ERβ pathways, thus reducing the apoptosis induced by HIBD and exerting a neuroprotective effect on neonatal mice with HIBD.

Role of Ubiquitin-Proteasome and Autophagy-Lysosome Pathways in α-Synuclein Aggregate Clearance

Synuclein aggregation in neuronal cells is the primary underlying cause of synucleinopathies. Changes in gene expression patterns, structural modifications, and altered interactions with other cellular proteins often trigger aggregation of α-synuclein, which accumulates as oligomers or fibrils in Lewy bodies. Although fibrillar forms of α-synuclein are primarily considered pathological, recent studies have revealed that even the intermediate states of aggregates are neurotoxic, complicating the development of therapeutic interventions. Autophagy and ubiquitin-proteasome pathways play a significant role in maintaining the soluble levels of α-synuclein inside cells; however, the heterogeneous nature of the aggregates presents a significant bottleneck to its degradation by these cellular pathways. With studies focused on identifying the proteins that modulate synuclein aggregation and clearance, detailed mechanistic insights are emerging about the individual and synergistic effects of these degradation pathways in regulating soluble α-synuclein levels. In this article, we discuss the impact of α-synuclein aggregation on autophagy-lysosome and ubiquitin-proteasome pathways and the therapeutic strategies that target various aspects of synuclein aggregation or degradation via these pathways. Additionally, we also highlight the natural and synthetic compounds that have shown promise in alleviating the cellular damage caused due to synuclein aggregation.

A breakdown in microglial metabolic reprogramming causes internalization dysfunction of α-synuclein in a mouse model of Parkinson’s disease

Background

The α-synuclein released by neurons activates microglia, which then engulfs α-synuclein for degradation via autophagy. Reactive microglia are a major pathological feature of Parkinson’s disease (PD), although the exact role of microglia in the pathogenesis of PD remains unclear. Transient receptor potential vanilloid type 1 (TRPV1) channels are nonselective cation channel protein that have been proposed as neuroprotective targets in neurodegenerative diseases.

Methods

Using metabolic profiling, microglia energy metabolism was measured including oxidative phosphorylation and aerobic glycolysis. The mRFP-GFP-tagged LC3 reporter was introduced to characterize the role of TRPV1 in microglial autophagy. α-synuclein preformed fibril (PFF) TRPV1^flox/flox; Cx3cr1^Cre mouse model of sporadic PD were employed to study the capacity of TRPV1 activation to attenuate neurodegeneration process.

Results

We found that acute exposure to PFF caused microglial activation as a result of metabolic reprogramming from oxidative phosphorylation to aerobic glycolysis via the AKT–mTOR–HIF-1α pathway. Activated microglia eventually reached a state of chronic PFF-tolerance, accompanied by broad defects in energy metabolism. We showed that metabolic boosting by treatment with the TRPV1 agonist capsaicin rescued metabolic impairments in PFF-tolerant microglia and also defects in mitophagy caused by disruption of the AKT–mTOR–HIF-1α pathway. Capsaicin attenuated phosphorylation of α-synuclein in primary neurons by boosting phagocytosis in PFF-tolerant microglia in vitro. Finally, we found that behavioral deficits and loss of dopaminergic neurons were accelerated in the PFF TRPV1^flox/flox; Cx3cr1^Cre mouse model of sporadic PD. We identified defects in energy metabolism, mitophagy and phagocytosis of PFF in microglia from the substantia nigra pars compacta of TRPV1^flox/flox; Cx3cr1^Cre mice.

Conclusion

The findings suggest that modulating microglial metabolism might be a new therapeutic strategy for PD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-022-02484-0.

A Balance Between Autophagy and Other Cell Death Modalities in Cancer

Autophagy is an intracellular self-digestive process involved in catabolic degradation of damaged proteins, and organelles, and the elimination of cellular pathogens. Initially, autophagy was considered as a prosurvival mechanism, but the following insights shed light on its prodeath function. Nowadays, autophagy is established as a crucial player in the development of various diseases through interaction with other molecular pathways within a cell. Additionally, disturbance in autophagy is one of the main pathological alterations that lead to resistance of cancer cells to treatment. These autophagy-related pathologies gave rise to the development of new therapeutic drugs. Here, we summarize the current knowledge on the autophagic role in disease pathogenesis, particularly in cancer, and the interplay between autophagy and other cell death modalities in order to combat cancer.

Role of Na+/K+-ATPase in ischemic stroke: in-depth perspectives from physiology to pharmacology

Na⁺/K⁺-ATPase (NKA) is a large transmembrane protein expressed in all cells. It is well studied for its ion exchanging function, which is indispensable for the maintenance of electrochemical gradients across the plasma membrane and herein neuronal excitability. The widely recognized pump function of NKA closely depends on its unique structure features and conformational changes upon binding of specific ions. Various Na⁺-dependent secondary transport systems are rigorously controlled by the ionic gradients generated by NKA and are essential for multiple physiological processes. In addition, roles of NKA as a signal transducer have also been unveiled nowadays. Plethora of signaling cascades are defined including Src-Ras-MAPK signaling, IP3R-mediated calcium oscillation, inflammation, and autophagy though most underlying mechanisms remain elusive. Ischemic stroke occurs when the blood flow carrying nutrients and oxygen into the brain is disrupted by blood clots, which is manifested by excitotoxicity, oxidative stress, inflammation, etc. The protective effect of NKA against ischemic stress is emerging gradually with the application of specific NKA inhibitor. However, NKA-related research is limited due to the opposite effects caused by NKA inhibitor at lower doses. The present review focuses on the recent progression involving different aspects about NKA in cellular homeostasis to present an in-depth understanding of this unique protein. Moreover, essential roles of NKA in ischemic pathology are discussed to provide a platform and bright future for the improvement in clinical research on ischemic stroke.

Idebenone-Activating Autophagic Degradation of α-Synuclein via Inhibition of AKT-mTOR Pathway in a SH-SY5Y-A53T Model of Parkinson's Disease: A Network Pharmacological Approach

Background

Parkinson's disease (PD) is the second most common neurodegenerative disease worldwide, which currently lacks disease-modifying therapy to slow down its progression. Idebenone, a coenzyme Q10 (CQ10) analogue, is a well-known antioxidant and has been used to treat neurological disorders. However, the mechanism of Idebenone on PD has not been fully elucidated. This study aims to predict the potential targets of Idebenone and explore its therapeutic mechanism against PD.

Method

We obtained potential therapeutic targets through database prediction, followed by Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis. Next, we constructed and analyzed a protein-protein interaction network (PPI) and a drug-target-pathway-disease network. A molecular docking test was conducted to identify the interactions between Idebenone and potential targets. Lastly, a PD cell line of SH-SY5Y overexpressing mutant α-synuclein was used to validate the molecular mechanism.

Result

A total of 87 targets were identified based on network pharmacology. The enrichment analysis highlighted manipulation of MAP kinase activity and the PI3K-AKT signaling pathway as potential pharmacological targets for Idebenone against PD. Additionally, molecular docking showed that AKT and MAPK could bind tightly with Idebenone. In the cell model of PD, Idebenone activated autophagy and promoted α-synuclein degradation by suppressing the AKT/mTOR pathway. Pretreating cells with chloroquine (CQ) to block autophagic flux could diminish the pharmacological effect of Idebenone to clear α-synuclein.

Conclusion

This study demonstrated that Idebenone exerts its anti-PD effects by enhancing autophagy and clearance of α-synuclein, thus providing a theoretical and experimental basis for Idebenone therapy against PD.