The Nrf2-NLRP3-caspase-1 axis mediates the neuroprotective effects of Celastrol in Parkinson's disease

FOXA1 Suppresses Endoplasmic Reticulum Stress, Oxidative Stress, and Neuronal Apoptosis in Parkinson's Disease by Activating PON2 Transcription

Endoplasmic reticulum (ER) stress and oxidative stress (OS) are often related states in pathological conditions including Parkinson's disease (PD). This study investigates the role of anti-oxidant protein paraoxonase 2 (PON2) in ER stress and OS in PD, along with its regulatory molecule. PD was induced in C57BL/6 mice using 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine hydrochloride (MPTP) treatment and in SH-SY5Y cells using 1-methyl-4-phenylpyridinium. PON2 was found to be poorly expressed in the substantia nigra pars compacta (SNc) of PD mice, and its overexpression improved motor coordination of mice. Through the evaluation of tyrosine hydroxylase, dopamine transporter, reactive oxygen species (ROS), and C/EBP homologous protein (CHOP) levels and neuronal loss in mice, as well as the examination of CHOP, glucose-regulated protein 94 (GRP94), GRP78, caspase-12, sarco/endoplasmic reticulum calcium ATPase 2, malondialdehyde, and superoxide dismutase levels in SH-SY5Y cells, we observed that PON2 overexpression mitigated ER stress, OS, and neuronal apoptosis both in vivo and in vitro. Forkhead box A1 (FOXA1) was identified as a transcription factor binding to the PON2 promoter to activate its transcription. Upregulation of FOXA1 similarly protected against neuronal loss by alleviating ER stress and OS, while the protective roles were abrogated by additional PON2 silencing. In conclusion, this study demonstrates that FOXA1-mediated transcription of PON2 alleviates ER stress and OS, ultimately reducing neuronal apoptosis in PD.

Inhibitory mechanisms of decoy receptor 3 in cecal ligation and puncture-induced sepsis

Despite its high mortality, specific and effective drugs for sepsis are lacking. Decoy receptor 3 (DcR3) is a potential biomarker for the progression of inflammatory diseases. The recombinant human DcR3-Fc chimera protein (DcR3.Fc) suppresses inflammatory responses in mice with sepsis, which is critical for improving survival. The Fc region can exert detrimental effects on the patient, and endogenous peptides are highly conducive to clinical application. However, the mechanisms underlying the effects of DcR3 on sepsis are unknown. Herein, we aimed to demonstrate that DcR3 may be beneficial in treating sepsis and investigated its mechanism of action. Recombinant DcR3 was obtained in vitro. Postoperative DcR3 treatment was performed in mouse models of lipopolysaccharide- and cecal ligation and puncture (CLP)-induced sepsis, and their underlying molecular mechanisms were explored. DcR3 inhibited sustained excessive inflammation in vitro, increased the survival rate, reduced the proinflammatory cytokine levels, changed the circulating immune cell composition, regulated the gut microbiota, and induced short-chain fatty acid synthesis in vivo. Thus, DcR3 protects against CLP-induced sepsis by inhibiting the inflammatory response and apoptosis. Our study provides valuable insights into the molecular mechanisms associated with the protective effects of DcR3 against sepsis, paving the way for future clinical studies.

IMPORTANCE

Sepsis affects millions of hospitalized patients worldwide each year, but there are no sepsis-specific drugs, which makes sepsis therapies urgently needed. Suppression of excessive inflammatory responses is important for improving the survival of patients with sepsis. Our results demonstrate that DcR3 ameliorates sepsis in mice by attenuating systematic inflammation and modulating gut microbiota, and unveil the molecular mechanism underlying its anti-inflammatory effect.

Celastrol enhances the viability of random-pattern skin flaps by regulating autophagy through the AMPK-mTOR-TFEB axis

In reconstructive and plastic surgery, random-pattern skin flaps (RPSF) are often used to correct defects. However, their clinical usefulness is limited due to their susceptibility to necrosis, especially on the distal side of the RPSF. This study validates the protective effect of celastrol (CEL) on flap viability and explores in terms of underlying mechanisms of action. The viability of different groups of RPSF was evaluated by survival zone analysis, laser doppler blood flow, and histological analysis. The effects of CEL on flap angiogenesis, apoptosis, oxidative stress, and autophagy were evaluated by Western blot, immunohistochemistry, and immunofluorescence assays. Finally, its mechanistic aspects were explored by autophagy inhibitor and Adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) inhibitor. On the seventh day after surgery, the survival area size, blood supply, and microvessel count of RPSF were augmented following the administration of CEL. Additionally, CEL stimulated angiogenesis, suppressed apoptosis, and lowered oxidative stress levels immediately after elevated autophagy in ischemic regions; These effects can be reversed using the autophagy inhibitor chloroquine (CQ). Specifically, CQ has been observed to counteract the protective impact of CEL on the RPSF. Moreover, it has also been discovered that CEL triggers the AMPK-mTOR-TFEB axis activation in the area affected by ischemia. In CEL-treated skin flaps, AMPK inhibitors were demonstrated to suppress the AMPK-mTOR-TFEB axis and reduce autophagy levels. This investigation suggests that CEL benefits the survival of RPSF by augmenting angiogenesis and impeding oxidative stress and apoptosis. The results are credited to increased autophagy, made possible by the AMPK-mTOR-TFEB axis activation.

Celastrol inhibits oligodendrocyte and neuron ferroptosis to promote spinal cord injury recovery

BACKGROUND

Spinal cord injury (SCI) is a traumatic injury to the central nervous system and can cause lipid peroxidation in the spinal cord. Ferroptosis, an iron-dependent programmed cell death, plays a key role in the pathophysiology progression of SCI. Celastrol, a widely used antioxidant drug, has potential therapeutic value for nervous system.

PURPOSE

To investigate whether celastrol can be a reliable candidate for ferroptosis inhibitor and the molecular mechanism of celastrol in repairing SCI by inhibiting ferroptosis.

METHODS

First, a rat SCI model was constructed, and the recovery of motor function was observed after treatment with celastrol. The regulatory effect of celastrol on ferroptosis pathway Nrf2-xCT-GPX4 was detected by Western blot and immunofluorescence. Finally, the ferroptosis model of neurons and oligodendrocytes was constructed in vitro to further verify the mechanism of inhibiting ferroptosis by celastrol.

RESULTS

Our results demonstrated that celastrol promoted the recovery of spinal cord tissue and motor function in SCI rats. Further in vitro and in vivo studies showed that celastrol significantly inhibited ferroptosis in neurons and oligodendrocytes and reduced the accumulation of ROS. Finally, we found that celastrol could inhibit ferroptosis by up-regulating the Nrf2-xCT-GPX4 axis to repair SCI.

CONCLUSION

Celastrol effectively inhibits ferroptosis after SCI by upregulating the Nrf2-xCT-GPX4 axis, reducing the production of lipid ROS, protecting the survival of neurons and oligodendrocytes, and improving the functional recovery.

TMEM79 Ameliorates Cerebral Ischemia/Reperfusion Injury Through Regulating Inflammation and Oxidative Stress via the Nrf2/NLRP3 Pathway

BACKGROUND

Cerebral ischemia/reperfusion injury (CIRI) is still a complicated disease with high fatality rates worldwide. Transmembrane Protein 79 (TMEM79) regulates inflammation and oxidative stress in some other diseases.

METHODS

CIRI mouse model was established using C57BL/6J mice through middle cerebral artery occlusion-reperfusion (MCAO/R), and BV2 cells were subjected to oxygen and glucose deprivation/reoxygenation (OGD/R) to simulate CIRI. Brain tissue or BV2 cells were transfected or injected with lentivirus-carried TMEM79 overexpression vector. The impact of TMEM79 on CIRI-triggered oxidative stress was ascertained by dihydroethidium (DHE) staining and examination of oxidative stress indicators. Regulation of TMEM79 in neuronal apoptosis and inflammation was determined using TUNEL staining and ELISA.

RESULTS

TMEM79 overexpression mitigated neurological deficit induced by MCAO/R and decreased the extent of cerebral infarct. TMEM79 prevented neuronal death in brain tissue of MCAO/R mouse model and suppressed inflammatory response by reducing inflammatory cytokines levels. Moreover, TMEM79 significantly attenuated inflammation and oxidative stress caused by OGD/R in BV2 cells. TMEM79 facilitated the activation of Nrf2 and inhibited NLRP3 and caspase-1 expressions. Rescue experiments indicated that the Nrf2/NLRP3 signaling pathway mediated the mitigative effect of TMEM79 on CIRI in vivo and in vitro.

CONCLUSION

Overall, TMEM79 was confirmed to attenuate CIRI via regulating the Nrf2/NLRP3 signaling pathway.

Celastrol ameliorates hypoxic-ischemic brain injury in neonatal rats by reducing oxidative stress and inflammation

BACKGROUND

Hypoxic-ischemic encephalopathy (HIE) is caused by perinatal hypoxia and subsequent reductions in cerebral blood flow and is one of the leading causes of severe disability or death in newborns. Despite its prevalence, we currently lack an effective drug therapy to combat HIE. Celastrol (Cel) is a pentacyclic triterpene extracted from Tripterygium Wilfordi that can protect against oxidative stress, inflammation, and cancer. However, whether Cel can alleviate neonatal hypoxic-ischemic (HI) brain damage remains unclear.

METHODS

Here, we established both in vitro and in vivo models of HI brain damage using CoCl2-treated PC12 cells and neonatal rats, respectively, and explored the neuroprotective effects of Cel in these models.

RESULTS

Analyses revealed that Cel administration reduced brain infarction size, microglia activation, levels of inflammation factors, and levels of oxidative stress markers by upregulating levels of p-AMPKα, Nrf2, HO-1, and by downregulating levels of TXNIP and NLRP3. Conversely, these beneficial effects of Cel on HI brain damage were largely inhibited by AMPKα inhibitor Compound C and its siRNA.

CONCLUSIONS

We present compelling evidence that Cel decreases inflammation and oxidative stress through the AMPKα/Nrf2/TXNIP signaling pathway, thereby alleviating neonatal HI brain injury. Cel therefore represents a promising therapeutic agent for treating HIE.

IMPACT

We firstly report that celastrol can ameliorate neonatal hypoxic-ischemic brain injury both in in vivo and in vitro, which represents a promising therapeutic agent for treating related brain injuries. Celastrol activates the AMPKα/Nrf2/TXNIP signaling pathway to relieve oxidative stress and inflammation and thereby alleviates neonatal hypoxic-ischemic brain injury.

DDIT3 aggravates TMJOA cartilage degradation via Nrf2/HO-1/NLRP3-mediated autophagy

OBJECTIVE

DNA damage-inducible transcript 3 (DDIT3), as a downstream transcription factor of endoplasmic reticulum stress, is reported to regulate chondrogenic differentiation under physiological and pathological state. However, the specific involvement of DDIT3 in the degradation of condylar cartilage of temporomandibular joint osteoarthritis (TMJOA) is unclarified.

DESIGN

The expression patterns of DDIT3 in condylar cartilage from monosodium iodoacetate-induced TMJOA mice were examined to uncover the potential role of DDIT3 in TMJOA. The Ddit3 knockout (Ddit3-/-) mice and their wildtype littermates (Ddit3+/+) were used to clarify the effect of DDIT3 on cartilage degradation. Primary condylar chondrocytes and ATDC5 cells were applied to explore the mechanisms of DDIT3 on autophagy and extracellular matrix (ECM) degradation in chondrocytes. The autophagy inhibitor chloroquine (CQ) was used to determine the effect of DDIT3-inhibited autophagy in vivo.

RESULTS

DDIT3 were highly expressed in condylar cartilage from TMJOA mice. Ddit3 knockout alleviated condylar cartilage degradation and subchondral bone loss, compared with their wildtype littermates. In vitro study demonstrated that DDIT3 exacerbated ECM degradation in chondrocytes induced by TNF-α through inhibiting autophagy. The intraperitoneal injection of CQ further confirmed that Ddit3 knockout alleviated cartilage degradation in TMJOA through activating autophagy in vivo.

CONCLUSIONS

Our findings identified the crucial role of DDIT3-inhibited autophagy in condylar cartilage degradation during the development of TMJOA.

Mitochondrial dysfunction in chronic neuroinflammatory diseases (Review)

Chronic neuroinflammation serves a key role in the onset and progression of neurodegenerative disorders. Mitochondria serve as central regulators of neuroinflammation. In addition to providing energy to cells, mitochondria also participate in the immunoinflammatory response of neurodegenerative disorders including Alzheimer's disease, Parkinson's disease, multiple sclerosis and epilepsy, by regulating processes such as cell death and inflammasome activation. Under inflammatory conditions, mitochondrial oxidative stress, epigenetics, mitochondrial dynamics and calcium homeostasis imbalance may serve as underlying regulatory mechanisms for these diseases. Therefore, investigating mechanisms related to mitochondrial dysfunction may result in therapeutic strategies against chronic neuroinflammation and neurodegeneration. The present review summarizes the mechanisms of mitochondria in chronic neuroinflammatory diseases and the current treatment approaches that target mitochondrial dysfunction in these diseases.

Celastrol Ameliorates Neuronal Mitochondrial Dysfunction Induced by Intracerebral Hemorrhage via Targeting cAMP-Activated Exchange Protein-1

Mitochondrial dysfunction contributes to the development of secondary brain injury (SBI) following intracerebral hemorrhage (ICH) and represents a promising therapeutic target. Celastrol, the primary active component of Tripterygium wilfordii, is a natural product that exhibits mitochondrial and neuronal protection in various cell types. This study aims to investigate the neuroprotective effects of celastrol against ICH-induced SBI and explore its underlying mechanisms. Celastrol improves neurobehavioral and cognitive abilities in mice with autologous blood-induced ICH, reduces neuronal death in vivo and in vitro, and promotes mitochondrial function recovery in neurons. Single-cell nuclear sequencing reveals that the cyclic adenosine monophosphate (cAMP)/cAMP-activated exchange protein-1 (EPAC-1) signaling pathways are impacted by celastrol. Celastrol binds to cNMP (a domain of EPAC-1) to inhibit its interaction with voltage-dependent anion-selective channel protein 1 (VDAC1) and blocks the opening of mitochondrial permeability transition pores. After neuron-specific knockout of EPAC1, the neuroprotective effects of celastrol are diminished. In summary, this study demonstrates that celastrol, through its interaction with EPAC-1, ameliorates mitochondrial dysfunction in neurons, thus potentially improving SBI induced by ICH. These findings suggest that targeting EPAC-1 with celastrol can be a promising therapeutic approach for treating ICH-induced SBI.

Baohuoside I suppresses the NLRP3 inflammasome activation via targeting GPER to fight against Parkinson's disease

BACKGROUND

Accumulating evidence indicates the crucial role of microglia-mediated inflammation and the NLR family pyrin domain containing 3 (NLRP3) inflammasome-mediated pyroptosis in the pathogenesis of Parkinson's disease (PD). Baohuoside I, a natural flavonoid extracted from Herba Epimedii, has been shown to possess anti-inflammatory effects, but its potential neuroprotective effects and mechanism against PD have not been documented.

STUDY DESIGN AND METHODS

The anti-inflammatory effects of Baohuoside I were evaluated by LPS-induced BV2 cells or primary microglia isolated from wide type or G protein-coupled estrogen receptor (GPER) gene knockout mice. The underlying mechanism related to GPER-mediated NLRP3 inflammasome inhibition was further explored using LPS-induced GPER+/+ or GPER-/- mouse models of PD. The neuroprotective effects of Baohuoside I were detected through western blot analysis, real-time PCR, molecular docking, mouse behavioral tests, immunofluorescence, and immunohistochemistry.

RESULTS

Baohuoside I significantly alleviated LPS-induced neuroinflammation by inhibiting the activation of NF-κB signal and the increase of pyroptosis levels as evidenced by the downregulated expression of pyroptosis-related proteins (NLRP3, ASC, pro-Caspase-1, IL-1β) in microglia cells. Intragastric administration of Baohuoside I protected against LPS-induced motor dysfunction and loss of dopaminergic neurons, reduced pro-inflammatory cytokines expressions, and inhibited microglial (Iba-1) and astrocyte (GFAP) activation in the nigrostriatal pathway in LPS-induced mouse model of PD. Pretreatment with GPER antagonist G15 in microglia cells or GPER gene deletion in mice significantly blocked the inhibitory effects of Baohuoside I on LPS-induced neuroinflammation and activation of the NLRP3/ASC/Caspase-1 pathway. Molecular docking further indicated that Baohuoside I might bind to GPER directly with a binding energy of -10.4 kcal/mol.

CONCLUSION

Baohuoside I provides neuroprotective effects against PD by inhibiting the activation of the NF-κB signal and NLRP3/ASC/Caspase-1 pathway. The molecular target for its anti-inflammatory effects is proved to be GPER in the PD mouse model. Baohuoside I may be a valuable anti-neuroinflammatory agent and a drug with well-defined target for the treatment of PD.

Nrf2 activator Diethyl Maleate attenuates ROS mediated NLRP3 inflammasome activation in murine microglia

Microglia are the tissue-resident immune cells of the central nervous system. As a part of the innate immune response, NLR Family Pyrin Domain Containing Protein 3 (NLRP3) inflammasome activation leads to cleavage of caspase-1 and triggers secretion of proinflammatory cytokines and may also result in pyroptotic cell death. Inflammasome activation plays a crucial role in inflammatory conditions; aberrant activation of inflammasome contributes to the pathogenesis of neurodegenerative diseases. Diethyl Maleate (DEM) is a promising antiinflammatory chemical to alleviate inflammasome activation. In this study, NLRP3 inflammasome was activated in N9 murine microglia via 1 µg/ml LPS (Lipopolysaccharide) for 4 h and 5 mM ATP (Adenosine 5'-triphosphate) for 1 h, respectively. We demonstrated that 1 h pretreatment of DEM attenuated NLRP3 inflammasome activation in microglial cells. Besides, mitochondrial ROS decreased upon DEM pretreatment in inflammasome-induced cells. Likewise, it ameliorated pyroptotic cell death in microglia. DEM is a potent activator of Nrf2 transcription factor, the key regulator of the antioxidant response pathway. Nrf2 has been a significant target to decrease aberrant inflammasome activation through the antioxidant compounds, including DEM. Here, we have shown that DEM increased Nrf2 translocation to the nucleus, resulting in Nrf2 target gene expression in microglia. In conclusion, DEM is a promising protective agent against NLRP3 inflammasome activation.

Resveratrol Ameliorates Retinal Ischemia-Reperfusion Injury by Modulating the NLRP3 Inflammasome and Keap1/Nrf2/HO-1 Signaling Pathway

Glaucoma, as an ischemia-reperfusion (I/R) injury disease, leading irreversible blindness through the loss of retinal ganglion cells (RGCs), mediated by various pathways. Resveratrol (Res) is a polyphenolic compound that exerts protective effects against I/R injury in many tissues. This article aimed to expound the underlying mechanisms through which Res protects RGCs and reduces visual dysfunction in vivo. An experimental glaucoma model was created using 6-8-week wild-type male C57BL/6J mice. Res was injected intraperitoneally for 5 days. The mice were then grouped according to the number of days after surgery and whether Res treatment was administered. We applied the Brn3a-labeled immunofluorescence staining and flash electroretinography (ERG) to assess the survival of RGCs and visual function. The expression of components of the NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) inflammasome, the interleukin-1-beta (IL-1β), and vital indicators of kelch-like ECH-associated protein 1 (Keap1)/nuclear factor erythroid 2-related factor 2 (Nrf2)/heme-oxygenase 1 (HO-1) pathway at the protein and RNA levels were detected respectively. The survival of RGCs was reduced after surgery compared to controls, whereas Res application rescued RGCs and improved visual dysfunction. In conclusion, our results discovered that Res administration showed neuroprotective effects through inhibition of the NLRP3 inflammasome pathway and activation of Keap1/Nrf2/HO-1 pathway. Thus, we further elucidated the potential of Res in glaucoma therapy.

Platycodon D protects human nasal epithelial cells from pyroptosis through the Nrf2/HO-1/ROS signaling cascade in chronic rhinosinusitis

BACKGROUND

Pyroptosis has been demonstrated being closely associated with the inflammatory progression in chronic rhinosinusitis (CRS). However, platycodon D (PLD) has emerged as a key anti-inflammatory mediator in the inflammatory progression of various respiratory diseases. This study aims at investigating whether PLD could reduce inflammatory progression of CRS by inhibiting pyroptosis.

METHODS

Nasal mucosal tissues from patients with CRS and the control group (simple nasal septal deviation) were analyzed for morphological difference using hematoxylin & eosin staining and for the expression of pyroptosis-related makers by immunofluorescence (IF). Human nasal epithelial cells (HNEpCs) were cultured and co-stimulated with lipopolysaccharide (LPS)/adenosine triphosphate (ATP) to construct an in vitro cellular model simulating CRS. After pretreatment with PLD, EthD-I staining, TUNEL staining, transmission electron microscopy (TEM), and GSDMD-NT detection were performed to evaluate pyroptosis markers. The NLRP3 inflammasome was detected by IF and western blotting (WB). Reactive oxygen species (ROS) were detected by H2DCFDA staining, and mitochondrial membrane potential was evaluated by JC-1 staining. Mitochondrial morphology and structure were observed using TEM. The Nrf2/HO-1 antioxidant signaling pathway was detected using WB.

RESULTS

The nasal mucosa structure of patients with CRS exhibited significant damage, with a marked increase in the expression of pyroptosis-related proteins compared with the control group. LPS/ATP co-stimulation resulted in an increased expression of IL-18 and IL-1β in HNEpCs, causing significant damage to nuclear and cell membranes, GSDMD-NT accumulation around the cell membrane, and intracellular NLRP3 inflammasome activation. Furthermore, it led to increased ROS expression, significantly decreased mitochondrial membrane potential, and damaged mitochondrial structure. However, pretreatment with PLD significantly reversed the aforementioned trends and activated the Nrf2/HO-1 antioxidant signaling pathway.

CONCLUSIONS

The results of this study confirm that NLRP3-mediated pyroptosis plays a crucial role in the pathological process of nasal mucosal impairment in patients with CRS. PLD inhibits NLRP3-mediated pyroptosis, preventing inflammatory damage in HNEpCs of patients with CRS by activating the Nrf2/HO-1 antioxidant signaling pathway, which in turn reduces ROS production and ameliorates mitochondrial damage.

The cell-specific roles of Nrf2 in acute and chronic phases of ischemic stroke

Ischemic stroke refers to the sudden loss of blood flow in a specific area of the brain. It is the fifth leading cause of mortality and the leading cause of permanent disability. The transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) controls the production of several antioxidants and protective proteins and it has been investigated as a possible pharmaceutical target for reducing harmful oxidative events in brain ischemia. Each cell type exhibits different roles and behaviors in different phases post-stroke, which is comprehensive yet important to understand to optimize management strategies and goals for care for stroke patients. In this review, we comprehensively summarize the protective effects of Nrf2 in experimental ischemic stroke, emphasizing the role of Nrf2 in different cell types including neurons, astrocytes, oligodendrocytes, microglia, and endothelial cells during acute and chronic phases of stroke and providing insights on the neuroprotective role of Nrf2 on each cell type throughout the long term of stroke care. We also highlight the importance of targeting Nrf2 in clinical settings while considering a variety of important factors such as age, drug dosage, delivery route, and time of administration.

Interactions Between the Ubiquitin-Proteasome System, Nrf2, and the Cannabinoidome as Protective Strategies to Combat Neurodegeneration: Review on Experimental Evidence

Neurodegenerative disorders are chronic brain diseases that affect humans worldwide. Although many different factors are thought to be involved in the pathogenesis of these disorders, alterations in several key elements such as the ubiquitin-proteasome system (UPS), the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway, and the endocannabinoid system (ECS or endocannabinoidome) have been implicated in their etiology. Impairment of these elements has been linked to the origin and progression of neurodegenerative disorders, while their potentiation is thought to promote neuronal survival and overall neuroprotection, as proved with several experimental models. These key neuroprotective pathways can interact and indirectly activate each other. In this review, we summarize the neuroprotective potential of the UPS, ECS, and Nrf2 signaling, both separately and combined, pinpointing their role as a potential therapeutic approach against several hallmarks of neurodegeneration.

Celastrol ameliorates experimental autoimmune uveitis through STAT3 targeting and gut microenvironment reprofiling

BACKGROUND

Extensive research has revealed the favorable effects of celastrol (CEL) against various diseases, but the role of CEL in autoimmune uveitis remains unexplored.

METHODS

We first assessed the prophylactical and therapeutical effects of CEL on autoimmune uveitis via rat experimental autoimmune uveitis model. After network pharmacology, functional enrichment and molecular docking analyses, we predicted the potential target of CEL and validated its effect on EAU by clinical and histopathological scores, Evans blue staining, immunofluorescence assay and western blotting. Then we evaluated the role of CEL in the gut environment by 16S rRNA sequencing and untargeted metabolomic analysis.

RESULTS

We confirmed that CEL treatment suppressed the pathological TH17 response, inhibited the migration of inflammatory cells, and preserved the integrity of BRB via targeting STAT3-IL17 pathway. Furthermore, CEL was found to reduce the relative abundance of opportunistic pathogenic bacteria including Clostridium_sensu_stricto_1, Parasutterella and GCA-900066575, and enrich the relative abundance of beneficial Oscillospirales and Ruminococcus_torques_group in EAU rats by fecal 16S rRNA sequencing. Meanwhile, CEL treatment reshaped the gut metabolites in the EAU rats by increasing the relative concentrations of cholic acid, progesterone and guggulsterone, and decreasing the relative levels of isoproterenol, creatinine and phenylacetylglutamine.

CONCLUSIONS

CEL exerts its ameliorative effects on the experimental autoimmune uveitis through the dual mechanisms of targeting STAT3 and reprofiling the gut microenvironment.

Electroacupuncture Improves Neuronal Damage and Mitochondrial Dysfunction Through the TRPC1 and SIRT1/AMPK Signaling Pathways to Alleviate Parkinson's Disease in Mice

Parkinson's disease (PD) is a neurodegenerative disease that mainly manifests as cognitive decline and motor dysfunction, the treatment of which is still a major challenge in the clinical field. Acupuncture therapy has been shown in many studies to enhance the body's own immunity and disease resistance. This study mainly discusses the specific mechanism underlying electroacupuncture intervention in improving PD. Male C57BL/6 mice were intraperitoneally injected with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) to induce a mouse PD model, and the chorea trembling control area of the head of PD mice was treated by electroacupuncture. Western blotting was used to detect the expression of related proteins in mouse pathological samples; TUNEL measured neuronal apoptosis levels; Nissl staining observed neuronal damage; immunofluorescence and immunohistochemistry were used to detect the expression of Iba-1, TH, and α-syn in substantia nigra denser (SN). The expression levels of oxidative stress factors and inflammatory factors were measured by kits. Flow cytometry measured mitochondrial membrane potential and Ca2+ levels. MPTP intraperitoneal injection induced an increase in inflammatory factors in PD mice and promoted the oxidative stress response, and the inflammatory response was alleviated after electroacupuncture treatment. Electroacupuncture intervention effectively alters the decrease in oxidative stress levels and alleviates neuronal damage in PD mice. Electroacupuncture improves mitochondrial dysfunction induced by MPTP in PD mice by activating the SIRT1/AMPK signaling pathway. We also confirmed that knocking down TRPC1 can inhibit the SIRT1/AMPK signaling pathway, weaken the Ca2+ content in mouse neuronal tissue, and promote cell apoptosis. Electroacupuncture improves neuronal damage and alleviates PD in mice through the TRPC1 and SIRT1/AMPK signaling pathways. In addition, electroacupuncture therapy can improve MPTP-induced mitochondrial dysfunction in PD mice and alleviate the PD process.

Immunological dimensions of neuroinflammation and microglial activation: exploring innovative immunomodulatory approaches to mitigate neuroinflammatory progression

The increasing life expectancy has led to a higher incidence of age-related neurodegenerative conditions. Within this framework, neuroinflammation emerges as a significant contributing factor. It involves the activation of microglia and astrocytes, leading to the release of pro-inflammatory cytokines and chemokines and the infiltration of peripheral leukocytes into the central nervous system (CNS). These instances result in neuronal damage and neurodegeneration through activated nucleotide-binding domain and leucine-rich repeat containing (NLR) family pyrin domain containing protein 3 (NLRP3) and nuclear factor kappa B (NF-kB) pathways and decreased nuclear factor erythroid 2-related factor 2 (Nrf2) activity. Due to limited effectiveness regarding the inhibition of neuroinflammatory targets using conventional drugs, there is challenging growth in the search for innovative therapies for alleviating neuroinflammation in CNS diseases or even before their onset. Our results indicate that interventions focusing on Interleukin-Driven Immunomodulation, Chemokine (CXC) Receptor Signaling and Expression, Cold Exposure, and Fibrin-Targeted strategies significantly promise to mitigate neuroinflammatory processes. These approaches demonstrate potential anti-neuroinflammatory effects, addressing conditions such as Multiple Sclerosis, Experimental autoimmune encephalomyelitis, Parkinson's Disease, and Alzheimer's Disease. While the findings are promising, immunomodulatory therapies often face limitations due to Immune-Related Adverse Events. Therefore, the conduction of randomized clinical trials in this matter is mandatory, and will pave the way for a promising future in the development of new medicines with specific therapeutic targets.

Echinacoside exerts neuroprotection via suppressing microglial α-synuclein/TLR2/NF-κB/NLRP3 axis in parkinsonian models

BACKGROUND

Echinacoside (ECH), a natural active compound, was found to exert neuroprotection in Parkinson's disease (PD). However, the underlying molecular mechanisms remain controversial.

PURPOSE

This study aimed to explore the roles of ECH in PD and its engaged mechanisms.

CONCLUSION

In vivo, MPTP was adapted to construct subacute PD mouse model to explore the regulation of ECH on NLRP3 inflammasome. In vitro, α-synuclein (α-syn)/MPP+ was used to mediate the activation of NLRP3 inflammasome in BV2 cells, and the mechanism of ECH regulation of it was explored with molecular docking, immunofluorescence, Western blotting, and small molecule inhibitors.

CONCLUSION

The activation of microglial NLRP3 inflammasome could be evoked by MPTP in vitro, but its toxic metabolite MPP+ alone cannot trigger the activation of NLRP3 inflammasome in vitro, which requires α-synuclein (α-syn) priming. Exogenous α-syn could evoke microglial TLR2/NF-κB/NLRP3 axis, playing the priming role in MPP+ -mediated NLRP3 inflammasome activation. ECH can suppress the upregulation of α-syn in MPTP-treated mice and BV2 microglia. It can also suppress the activation of the TLR2/NF-κB/NLRP3 axis induced by α-syn.

CONCLUSION

ECH exerts neuroprotective effects by downregulating the TLR2/NF-κB/NLRP3 axis via reducing the expression of α-syn in the PD models.

Therapeutic considerations of bioactive compounds in Alzheimer's disease and Parkinson's disease: Dissecting the molecular pathways

Leading neurodegenerative diseases Alzheimer's disease (AD) and Parkinson's disease (PD) are characterized by the impairment of memory and motor functions, respectively. Despite several breakthroughs, there exists a lack of disease-modifying treatment strategies for these diseases, as the available drugs provide symptomatic relief and bring along side effects. Bioactive compounds are reported to bear neuroprotective properties with minimal toxicity, however, a detailed elucidation of their modes of neuroprotection is lacking. The review elucidates the neuroprotective mechanism(s) of some of the major phyto-compounds in pre-clinical and clinical studies of AD and PD to understand their potential in combating these diseases. Curcumin, eugenol, resveratrol, baicalein, sesamol and so on have proved efficient in countering the pathological hallmarks of AD and PD. Curcumin, resveratrol, caffeine and so on have reached the clinical phases of these diseases, while aromadendrin, delphinidin, cyanidin and xanthohumol are yet to be extensively explored in pre-clinical phases. The review highlights the need for extensive investigation of these compounds in the clinical stages of these diseases so as to utilize their disease-modifying abilities in the real field of treatment. Moreover, poor pharmacokinetic properties of natural compounds are constraints to their therapeutic yields and this review suggests a plausible contribution of nanotechnology in overcoming these limitations.

Celastrol as a candidate drug for silicosis: From bioinformatics and network pharmacology to experimental validation

Silicosis, a highly lethal occupational respiratory disease characterized by irreversible pulmonary fibrosis, remains challenging to treat due to its unclear pathogenesis. In this study, bioinformatics, network pharmacology, and experimental validation were combined to explore potential mechanisms and therapeutic drugs for silicosis. First, the differentially expressed genes（DEGs）and pathway enrichment in pulmonary fibrosis were identified by GO and KEGG analysis. Next, the differential genes were submitted to cMap database for drug prediction and celastrol stood out as the most promising candidate drug. Then, network pharmacology analysis identified pharmacological targets of celastrol and demonstrated that celastrol could regulate JAK-STAT, MAPK, and Toll-like receptor signaling pathways. Finally, we verified the therapeutic role and mechanism of celastrol on silicosis. In vivo, celastrol significantly ameliorated CS-induced inflammation and fibrosis in silicosis mice, including inflammatory cell infiltration, collagen fiber and extracellular matrix deposition, fibroblast activation and related factor expression. Moreover, it dramatically improved lung respiratory function of silicosis mice. In vitro, celastrol suppressed CS-induced cytokine expression, apoptosis of macrophages and activation of Stat3 and Erk1/2 signals. Overall, our research identified and verified celastrol as a novel and promising candidate drug for silicosis.

Pyroptosis in neurodegenerative diseases: from bench to bedside

The central nervous system regulates all aspects of physiology to some extent. Neurodegenerative diseases (NDDs) lead to the progressive loss and dysfunction of neurons, which are particularly evident in Alzheimer's disease, Parkinson's disease, and many other conditions. NDDs are multifactorial diseases with complex pathogeneses, and there has been a rapid increase in the prevalence of NDDs. However, none of these diseases can be cured, making the development of novel treatment strategies an urgent necessity. Numerous studies have indicated how pyroptosis induces inflammation and affects many aspects of NDD. Therefore, components related to pyroptosis are potential therapeutic candidates and are attracting increasing attention. Here, we review the role of pyroptosis in the pathogenesis of NDDs and potential treatment options. Additionally, several of the current drugs and relevant inhibitors are discussed. Through this article, we provide theoretical support for exploring new therapeutic targets and updating clinical treatment strategies for NDDs. Notably, pyroptosis, a recently widely studied mode of cell death, is still under-researched compared to other traditional forms of cell death. Moreover, the focus of research has been on the onset and progression of NDDs, and the lack of organ-specific target discovery and drug development is a common problem for many basic studies. This urgent problem requires scientists and companies worldwide to collaborate in order to develop more effective drugs against NDDs.

Emerging trends and hotspots of Nuclear factor erythroid 2-related factor 2 in nervous system diseases

BACKGROUND

The Nuclear factor erythroid 2-related factor 2 (NRF2) transcription factor has attracted much attention in the context of neurological diseases. However, none of the studies have systematically clarified this field's research hotspots and evolution rules.

AIM

To investigate the research hotspots, evolution patterns, and future research trends in this field in recent years.

METHODS

We conducted a comprehensive literature search in the Web of Science Core Collection database using the following methods: (((((TS=(NFE2 L2)) OR TS=(Nfe2 L2 protein, mouse)) OR TS=(NF-E2-Related Factor 2)) OR TS=(NRF2)) OR TS=(NFE2L2)) OR TS=(Nuclear factor erythroid2-related factor 2) AND (((((((TS=(neurological diseases)) OR TS=(neurological disorder)) OR TS=(brain disorder)) OR TS=(brain injury)) OR TS=(central nervous system disease)) OR TS=(CNS disease)) OR TS=(central nervous system disorder)) OR TS=(CNS disorder) AND Language = English from 2010 to 2022. There are just two forms of literature available: Articles and reviews. Data were processed with the software Cite-Space (version 6.1. R6).

RESULTS

We analyzed 1884 articles from 200 schools in 72 countries/regions. Since 2015, the number of publications in this field has increased rapidly. China has the largest number of publications, but the articles published in the United States have better centrality and H-index. Among the top ten authors with the most published papers, five of them are from China, and the author with the most published papers is Wang Handong. The institution with the most articles was Nanjing University. To their credit, three of the top 10 most cited articles were written by Chinese scholars. The keyword co-occurrence map showed that "oxidative stress", "NRF2", "activation", "expression" and "brain" were the five most frequently used keywords.

CONCLUSION

Research on the role of NRF2 in neurological diseases continues unabated. Researchers in developed countries published more influential papers, while Chinese scholars provided the largest number of articles. There have been numerous studies on the mechanism of NRF2 transcription factor in neurological diseases. NRF2 is also emerging as a potentially effective target for the treatment of neurological diseases. However, despite decades of research, our knowledge of NRF2 transcription factor in nervous system diseases is still limited. Further studies are needed in the future.

To re-examine the intersection of microglial activation and neuroinflammation in neurodegenerative diseases from the perspective of pyroptosis

Neurodegenerative diseases (NDs), such as Alzheimer's disease, Parkinson's disease, Huntington's disease, and motor neuron disease, are diseases characterized by neuronal damage and dysfunction. NDs are considered to be a multifactorial disease with diverse etiologies (immune, inflammatory, aging, genetic, etc.) and complex pathophysiological processes. Previous studies have found that neuroinflammation and typical microglial activation are important mechanisms of NDs, leading to neurological dysfunction and disease progression. Pyroptosis is a new mode involved in this process. As a form of programmed cell death, pyroptosis is characterized by the expansion of cells until the cell membrane bursts, resulting in the release of cell contents that activates a strong inflammatory response that promotes NDs by accelerating neuronal dysfunction and abnormal microglial activation. In this case, abnormally activated microglia release various pro-inflammatory factors, leading to the occurrence of neuroinflammation and exacerbating both microglial and neuronal pyroptosis, thus forming a vicious cycle. The recognition of the association between pyroptosis and microglia activation, as well as neuroinflammation, is of significant importance in understanding the pathogenesis of NDs and providing new targets and strategies for their prevention and treatment.

Development of novel celastrol-ligustrazine hybrids as potent peroxiredoxin 1 inhibitors against lung cancer

The disruption of oxidation-reduction equilibrium through inhibiting reactive oxygen species (ROS) clearance or enhancing ROS production has emerged as a novel and promising strategy for cancer therapy. Herein, a series of celastrol-ligustrazine hybrids were designed and synthesized as effective ROS promoters, and their biological activities were further evaluated. Among them, compound 7e stood out as the most potent peroxiredoxin 1 (PRDX1) inhibitor (IC50 = 0.164 μM), which was significant super to the recognized PRDX1 inhibitor Conoidin A (IC50 = 14.80 μM) and the control compound celastrol (IC50 = 1.622 μM). Furthermore, 7e dramatically promoted intracellular ROS accumulation, and inhibited the proliferation, invasion and migration of cancer cells besides inducing apoptosis in vitro. Additionally, 7e suppressed the key signaling pathways (AKT and ERK) and promoted the expression of apoptosis-related proteins (cleaved caspase-3/8 and cleaved PARP) in A549 cells, which resulted in the prevention of tumor progression. Most importantly, compound 7e (TGI = 77.47%) showed more considerable in vivo antitumor efficacy and less toxicity than celastrol (TGI = 71.00%). Overall, this work indicates 7e as the most potential PRDX1 inhibitor and may be a promising candidate for the therapy of lung cancer.

Biotin decorated celastrol-loaded ZIF-8 nano-drug delivery system targeted epithelial ovarian cancer therapy

Ovarian cancer (OC) stands as the second most prominent factor leading to cancer-related fatalities, characterized by a notably low five-year survival rate. The insidious onset of OC combined with its resistance to chemotherapy poses significant challenges in terms of treatment, emphasizing the utmost importance of developing innovative therapeutic agents. Despite its remarkable anti-tumor efficacy, celastrol (CEL) faces challenges regarding its clinical utilization in OC due to its restricted water solubility and notable side effects. In this study, celastrol (CEL) was encapsulated into Zeolitic imidazolate framework-8(ZIF-8) nanoparticle and grafted with biotin-conjugated polyethylene glycol (CEL@ZIF-8@PEG-BIO). Comprehensive comparisons of the physicochemical properties and anticancer activities of CEL and CEL@ZIF-8@PEG-BIO were conducted. Our findings revealed that CEL@ZIF-8@PEG-BIO exhibited favorable characteristics, including hydrodynamic diameters of 234.5 nm, excellent water solubility, high drug loading (31.60% ± 2.85), encapsulation efficiency (60.52% ± 2.79), and minimal side effects. Furthermore, CEL@ZIF-8@PEG-BIO can release chemicals in response to an acidic micro-environment, which is more likely a tumor micro-environment. In vitro, studies showed that CEL@ZIF-8@BIO inhibited cell proliferation, led to mitochondrial membrane potential (MMP) decline, and generated reactive oxygen species in OC cells. Both in vitro and in vivo experiments indicated that CEL@ZIF-8@PEG-BIO enhanced anti-tumor activity against OC via up-regulated apoptosis-promoting biomarkers and rendered cancer cell apoptosis via the P38/JNK MAPK signaling pathway. In conclusion, we have successfully developed a novel drug delivery system (CEL@ZIF-8@PEG-BIO), resulting in significant improvements in both water solubility and anti-tumor efficacy thereby providing valuable insights for future clinical drug development.

Research progress of NLRP3 inflammasome and its inhibitors with aging diseases

In recent years, a new target closely linked to a variety of diseases has appeared in the researchers' vision, which is the NLRP3 inflammasome. With the deepening of the study of NLRP3 inflammasome, it was found that it plays an extremely important role in a variety of physiological pathological processes, and NLRP3 inflammasome was also found to be associated with some age-related diseases. It is associated with the development of insulin resistance, Alzheimer's disease, Parkinson's, cardiovascular aging, hearing and vision loss. At present, the only clinical approach to the treatment of NLRP3 inflammasome-related diseases is to use anti-IL-1β antibodies, but NLRP3-specific inhibitors may be better than the IL-1β antibodies. This article reviews the relationship between NLRP3 inflammasome and aging diseases: summarizes some of the relevant experimental results reported in recent years, and introduces the biological signals or pathways closely related to the NLRP3 inflammasome in a variety of aging diseases, and also introduces some promising small molecule inhibitors of NLRP3 inflammasome for clinical treatment, such as: ZYIL1, DFV890 and OLT1177, they have excellent pharmacological effects and good pharmacokinetics.

The discovery of the new mechanism: Celastrol improves spinal cord injury by increasing cAMP through VIP-ADCYAP1R1-GNAS pathway

Spinal cord injury (SCI) is a debilitating condition that results in significant impairment of motor function and sensation. Despite the ongoing efforts to develop effective treatments, there are currently very limited options available for patients with SCI. Celastrol, a natural anti-inflammatory compound extracted from Tripterygium wilfordii, has been shown to exhibit anti-inflammatory and anti-apoptotic properties. In this study, we aimed to explore the therapeutic potential of celastrol for SCI and elucidate the underlying molecular mechanisms involved. We found that local tissue often experiences a significant decrease in cAMP content and occurrs apoptosis after SCI. However, the treatment of celastrol could promote the production of cAMP by up-regulating the VIP-ADCYAP1R1-GNAS pathway. This could effectively inhibit the phosphorylation of JNK and prevent apoptosis, ultimately improving the exercise ability after SCI. Together, our results reveal celastrol may be a promising therapeutic agent for the treatment of SCI.

IκB kinase β (IKKβ): Structure, transduction mechanism, biological function, and discovery of its inhibitors

The effective approach to discover innovative drugs will ask natural products for answers because of their complex and changeable structures and multiple biological activities. Inhibitory kappa B kinase beta (IKKβ), known as IKK2, is a key regulatory kinase responsible for the activation of NF-κB through its phosphorylation at Ser177 and Ser181 to promote the phosphorylation of inhibitors of kappa B (IκBs), triggering their ubiquitination and degradation to active the nuclear factor kappa-B (NF-κB) cascade. Chemical inhibition of IKKβ or its genetic knockout has become an effective method to block NF-κB-mediated proliferation and migration of tumor cells and inflammatory response. In this review, we summarized the structural feature and transduction mechanism of IKKβ and the discovery of inhibitors from natural resources (e.g. sesquiterpenoids, diterpenoids, triterpenoids, flavonoids, and alkaloids) and chemical synthesis (e.g. pyrimidines, pyridines, pyrazines, quinoxalines, thiophenes, and thiazolidines). In addition, the biosynthetic pathway of novel natural IKKβ inhibitors and their biological potentials were discussed. This review will provide inspiration for the structural modification of IKKβ inhibitors based on the skeleton of natural products or chemical synthesis and further phytochemistry investigations.

The central role of the NLRP3 inflammasome pathway in the pathogenesis of age-related diseases in the eye and the brain

With increasing age, structural changes occur in the eye and brain. Neuronal death, inflammation, vascular disruption, and microglial activation are among many of the pathological changes that can occur during ageing. Furthermore, ageing individuals are at increased risk of developing neurodegenerative diseases in these organs, including Alzheimer's disease (AD), Parkinson's disease (PD), glaucoma and age-related macular degeneration (AMD). Although these diseases pose a significant global public health burden, current treatment options focus on slowing disease progression and symptomatic control rather than targeting underlying causes. Interestingly, recent investigations have proposed an analogous aetiology between age-related diseases in the eye and brain, where a process of chronic low-grade inflammation is implicated. Studies have suggested that patients with AD or PD are also associated with an increased risk of AMD, glaucoma, and cataracts. Moreover, pathognomonic amyloid-β and α-synuclein aggregates, which accumulate in AD and PD, respectively, can be found in ocular parenchyma. In terms of a common molecular pathway that underpins these diseases, the nucleotide-binding domain, leucine-rich-containing family, and pyrin domain-containing-3 (NLRP3) inflammasome is thought to play a vital role in the manifestation of all these diseases. This review summarises the current evidence regarding cellular and molecular changes in the brain and eye with age, similarities between ocular and cerebral age-related diseases, and the role of the NLRP3 inflammasome as a critical mediator of disease propagation in the eye and the brain during ageing.

Celastrol relieves myocardial infarction-induced cardiac fibrosis by inhibiting NLRP3 inflammasomes in rats

BACKGROUND

Myocardial infarction (MI) triggers a strong inflammatory response mediating by NLRP3 inflammasome which is associated with cardiac fibrosis. The key players in this response are Interleukin (IL)-1 and IL-18, which are regulated by NLRP3 inflammasomes. Celastrol, a traditional Chinese medicine with strong anti-inflammatory activity, has recently reported as a cardioprotective agent. However, the mechanisms by which celastrol is cardioprotective in MI remain elusive. We hypothesized that Celastrol could reduce IL-1β and IL-18 expression and ameliorate myocardial fibrosis after myocardial infarction in rats, improve poor heart remodeling, and preserve heart function.

METHODS

Myocardial infarction (MI) was caused by ligating the left anterior descending of male SD rats. Celastrol (1 mg/kg) or saline was administered every other day for 4 weeks. Heart function and fibrosis were assessed. Inflammatory and fibrotic markers in the myocardia were evaluated with immunohistochemistry, western blot, and ELISA. Molecular docking was employed to predict Celastrol's binding to NLRP3 protein. The effects of Celastrol on the expression of NLRP3 inflammasome and myocardial fibrosis genes were then examined in vitro.

RESULTS

Celastrol maintained the left ventricular fractional shortening (FS) and ejection fraction (EF). Fibrosis was significantly reduced in animals treated with 1 mg/kg Celastrol (15.17 ± 1.82%) relative to controls (29.88 ± 4.28%). Celastrol also significantly reduced the NLRP3, IL-18, and IL-1β levels, together with macrophage and neutrophil infiltration in the myocardium. Molecular docking predicted that NLRP3 would bind tightly to Celastrol [Docking energy: -8.9 (kcal/mol)]. In vitro experiments showed reduced NLRP3 inflammasome and myocardial fibrosis-associated proteins expression in neonatal rat cardiac fibroblasts treated with Celastrol.

CONCLUSIONS

In post-MI rats, Celastrol, a naturally occurring active ingredient, was able to reduce myocardial fibrosis and improve cardiac function, according to our study. These effects may result from inhibiting the NLRP3 inflammasome and attenuating the early inflammatory storm after MI, suggesting that Celastrol may be useful in treating acute MI.

Celastrol as an emerging anticancer agent: Current status, challenges and therapeutic strategies

Celastrol is a pentacyclic triterpenoid extracted from the traditional Chinese medicine Tripterygium wilfordii Hook F., which has multiple pharmacological activities. In particular, modern pharmacological studies have demonstrated that celastrol exhibits significant broad-spectrum anticancer activities in the treatment of a variety of cancers, including lung cancer, liver cancer, colorectal cancer, hematological malignancies, gastric cancer, prostate cancer, renal carcinoma, breast cancer, bone tumor, brain tumor, cervical cancer, and ovarian cancer. Therefore, by searching the databases of PubMed, Web of Science, ScienceDirect and CNKI, this review comprehensively summarizes the molecular mechanisms of the anticancer effects of celastrol. According to the data, the anticancer effects of celastrol can be mediated by inhibiting tumor cell proliferation, migration and invasion, inducing cell apoptosis, suppressing autophagy, hindering angiogenesis and inhibiting tumor metastasis. More importantly, PI3K/Akt/mTOR, Bcl-2/Bax-caspase 9/3, EGFR, ROS/JNK, NF-κB, STAT3, JNK/Nrf2/HO-1, VEGF, AR/miR-101, HSF1-LKB1-AMPKα-YAP, Wnt/β-catenin and CIP2A/c-MYC signaling pathways are considered as important molecular targets for the anticancer effects of celastrol. Subsequently, studies of its toxicity and pharmacokinetic properties showed that celastrol has some adverse effects, low oral bioavailability and a narrow therapeutic window. In addition, the current challenges of celastrol and the corresponding therapeutic strategies are also discussed, thus providing a theoretical basis for the development and application of celastrol in the clinic.

Celastrol inhibits necroptosis by attenuating the RIPK1/RIPK3/MLKL pathway and confers protection against acute pancreatitis in mice

Necroptosis is a necrotic form of regulated cell death, which is primarily mediated by the receptor-interacting protein kinase 1 (RIPK1), RIPK3, and mixed lineage kinase domain-like (MLKL) pathway in a caspase-independent manner. Necroptosis has been found to occur in virtually all tissues and diseases evaluated, including pancreatitis. Celastrol, a pentacyclic triterpene extracted from the roots of Tripterygium wilfordii (thunder god vine), possesses potent anti-inflammatory and anti-oxidative activities. Yet, it is unclear whether celastrol has any effects on necroptosis and necroptotic-related diseases. Here we showed that celastrol significantly suppressed necroptosis induced by lipopolysaccharide (LPS) plus pan-caspase inhibitor (IDN-6556) or by tumor-necrosis factor-α in combination with LCL-161 (Smac mimetic) and IDN-6556 (TSI). In these in vitro cellular models, celastrol inhibited the phosphorylation of RIPK1, RIPK3, and MLKL and the formation of necrosome during necroptotic induction, suggesting its possible action on upstream signaling of the necroptotic pathway. Consistent with the known role of mitochondrial dysfunction in necroptosis, we found that celastrol significantly rescued TSI-induced loss of mitochondrial membrane potential. TSI-induced intracellular and mitochondrial reactive oxygen species (mtROS), which are involved in the autophosphorylation of RIPK1 and recruitment of RIPK3, were significantly attenuated by celastrol. Moreover, in a mouse model of acute pancreatitis that is associated with necroptosis, celastrol administration significantly reduced the severity of caerulein-induced acute pancreatitis accompanied by decreased phosphorylation of MLKL in pancreatic tissues. Collectively, celastrol can attenuate the activation of RIPK1/RIPK3/MLKL signaling likely by attenuating mtROS production, thereby inhibiting necroptosis and conferring protection against caerulein-induced pancreatitis in mice.

GSK-3β: An exuberating neuroinflammatory mediator in Parkinson's disease

Neuroinflammation is a critical degradative condition affecting neurons in the brain. Progressive neurodegenerative conditions such as Alzheimer's disease and Parkinson's disease (PD) have been strongly linked to neuroinflammation. The trigger point for inflammatory conditions in the cells and body is the physiological immune system. The immune response mediated by glial cells and astrocytes can rectify the physiological alterations occurring in the cell for the time being but prolonged activation leads to pathological progression. The proteins mediating such an inflammatory response, as per the available literature, are undoubtedly GSK-3β, NLRP3, TNF, PPARγ, and NF-κB, along with a few other mediatory proteins. NLRP3 inflammasome is undeniably a principal instigator of the neuroinflammatory response, but the regulatory pathways controlling its activation are still unclear, besides less clarity for the interplay between different inflammatory proteins. Recent reports have suggested the involvement of GSK-3β in regulating NLRP3 activation, but the exact mechanistic pathway remains vague. In the current review, we attempt to provide an elaborate description of crosstalk between inflammatory markers and GSK-3β mediated neuroinflammation progression, linking it to regulatory transcription factors and posttranslational modification of proteins. The recent clinical therapeutic advances targeting these proteins are also discussed in parallel to provide a comprehensive view of the progress made in PD management and lacunas still existing in the field.

Understanding the involvement of innate immunity and the Nrf2-NLRP3 axis on mitochondrial health in Parkinson's disease

Parkinson's disease (PD), a multifactorial movement disorder, is interlinked with numerous molecular pathways, including neuroinflammation, which is a critical factor in the development and progression of PD. Microglia play a central role in driving neuroinflammation through activation and overexpression of the M1 phenotype, which has a significant impact on mitochondria. Multiple regulators converge together, and among these, the NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasomes have been implicated in transmitting inflammatory and deleterious components to the mitochondria. Nuclear factor erythroid 2-related factor 2 (Nrf2) regulates the NLRP3 inflammasome and acts as the saviour of the mitochondria. Together, the NLRP3-Nrf2 axis functions in regulating mitochondrial function in the case of PD. It regulates fundamental processes such as oxidative stress, mitochondrial respiratory function, and mitochondrial dynamics. In this review, we discuss the contributions that a variety of miRNAs make to the regulation of the NLRP3 inflammasome and Nrf2, which can be used to target this important axis and contribute to the preservation of mitochondrial integrity. This axis may prove to be a crucial target for extending the lives of Parkinson's patients by deferring neuroinflammatory damage to mitochondria.

The Pharmacological Activity of Garlic (Allium sativum) in Parkinson's Disease: From Molecular Mechanisms to the Therapeutic Potential

Parkinson's disease (PD), one of the most common neurological diseases worldwide, is mainly characterized neuropathologically by the dopaminergic neurodegeneration in the substantia nigra pars compacta of the brainstem. Genetic and environmental factors contribute to PD pathophysiology through modulation of pleiotropic cellular mechanisms. The currently available treatment options focus only on replenishing dopamine and do not alter disease progression. Interestingly, garlic (Allium sativum), globally famed for its flavor and taste-enhancing properties, has shown protective activity in different PD models. Numerous chemical constituents of garlic, mainly the organosulfur compounds, have been shown to exhibit anti-Parkinsonian effects by targeting oxidative stress, mitochondrial impairment, and neuroinflammation-related signaling. However, despite its therapeutic potential against PD, the major bioactive components of garlic display some stability issues and some adverse effects. In the present review, we explore the therapeutic potential of garlic and its major constituents in PD, the molecular mechanisms responsible for its pharmaceutical activity, and the associated limitations that need to be overcome for its future potential use in clinical practice.

Surface-Modified Inhaled Microparticle-Encapsulated Celastrol for Enhanced Efficacy in Malignant Pleural Mesothelioma

Malignant pleural mesothelioma (MPM) is a rare and aggressive cancer affecting the pleural lining of the lungs. Celastrol (Cela), a pentacyclic triterpenoid, has demonstrated promising therapeutic potential as an antioxidant, anti-inflammatory, neuroprotective agent, and anti-cancer agent. In this study, we developed inhaled surface-modified Cela-loaded poly(lactic-co-glycolic) acid (PLGA) microparticles (Cela MPs) for the treatment of MPM using a double emulsion solvent evaporation method. The optimized Cela MPs exhibited high entrapment efficiency (72.8 ± 6.1%) and possessed a wrinkled surface with a mean geometric diameter of ~2 µm and an aerodynamic diameter of 4.5 ± 0.1 µm, suggesting them to be suitable for pulmonary delivery. A subsequent release study showed an initial burst release up to 59.9 ± 2.9%, followed by sustained release. The therapeutic efficacy of Cela MPs was evaluated against four mesothelioma cell lines, where Cela MP exhibited significant reduction in IC50 values, and blank MPs produced no toxicity to normal cells. Additionally, a 3D-spheroid study was performed where a single dose of Cela MP at 1.0 µM significantly inhibited spheroid growth. Cela MP was also able to retain the antioxidant activity of Cela only while mechanistic studies revealed triggered autophagy and an induction of apoptosis. Therefore, these studies highlight the anti-mesothelioma activity of Cela and demonstrate that Cela MPs are a promising inhalable medicine for MPM treatment.

Maresin1 can be a potential therapeutic target for nerve injury

Nerve injury significantly affects human motor and sensory function due to destruction of the integrity of nerve structure. In the wake of nerve injury, glial cells are activated, and synaptic integrity is destroyed, causing inflammation and pain hypersensitivity. Maresin1, an omega-3 fatty acid, is a derivative of docosahexaenoic acid. It has showed beneficial effects in several animal models of central and peripheral nerve injuries. In this review, we summarize the anti-inflammatory, neuroprotective and pain hypersensitivity effects of maresin1 in nerve injury and provide a theoretical basis for the clinical treatment of nerve injury using maresin1.

Phenolic and quinone methide nor-triterpenes as selective NLRP3 inflammasome inhibitors

Dysregulated inflammasome activity, particularly of the NLRP3 inflammasome, is associated with the development of several inflammatory diseases. The study of molecules directly targeting NLRP3 is an emerging field in the discovery of new therapeutic compounds for the treatment of inflammatory disorders. Friedelane triterpenes are biologically active phytochemicals having a wide range of activities including anti-inflammatory effects. In this work, we evaluated the potential anti-inflammatory activity of phenolic and quinonemethide nor-triterpenes (1-11) isolated from Maytenus retusa and some semisynthetic derivatives (12-16) through inhibition of the NLRP3 inflammasome in macrophages. Among them, we found that triterpenes 6 and 14 were the most potent, showing markedly reduced caspase-1 activity, IL-1β secretion (IC₅₀ = 1.15 µM and 0.19 µM, respectively), and pyroptosis (IC₅₀ = 2.21 µM and 0.13 µM, respectively). Further characterization confirmed their selective inhibition of NLRP3 inflammasome in both canonical and non-canonical activation pathways with no effects on AIM2 or NLRC4 inflammasome activation.

Signaling pathways in Parkinson's disease: molecular mechanisms and therapeutic interventions

Parkinson's disease (PD) is the second most common neurodegenerative disease worldwide, and its treatment remains a big challenge. The pathogenesis of PD may be related to environmental and genetic factors, and exposure to toxins and gene mutations may be the beginning of brain lesions. The identified mechanisms of PD include α-synuclein aggregation, oxidative stress, ferroptosis, mitochondrial dysfunction, neuroinflammation, and gut dysbiosis. The interactions among these molecular mechanisms complicate the pathogenesis of PD and pose great challenges to drug development. At the same time, the diagnosis and detection of PD are also one of obstacles to the treatment of PD due to its long latency and complex mechanism. Most conventional therapeutic interventions for PD possess limited effects and have serious side effects, heightening the need to develop novel treatments for this disease. In this review, we systematically summarized the pathogenesis, especially the molecular mechanisms of PD, the classical research models, clinical diagnostic criteria, and the reported drug therapy strategies, as well as the newly reported drug candidates in clinical trials. We also shed light on the components derived from medicinal plants that are newly identified for their effects in PD treatment, with the expectation to provide the summary and outlook for developing the next generation of drugs and preparations for PD therapy.

Targeting Mitochondrial Dysfunction in Neurodegenerative Diseases: Expanding the Therapeutic Approaches by Plant-Derived Natural Products

Mitochondria are the primary source of energy production in neurons, supporting the high energy consumption of the nervous system. Inefficient and dysfunctional mitochondria in the central nervous system have been implicated in neurodegenerative diseases. Therefore, targeting mitochondria offers a new therapeutic opportunity for neurodegenerative diseases. Many recent studies have proposed that plant-derived natural products, as pleiotropic, safe, and readily obtainable sources of new drugs, potentially treat neurodegenerative diseases by targeting mitochondria. In this review, we summarize recent advances in targeting mitochondria in neurotherapeutics by employing plant-derived natural products. We discuss the mechanism of plant-derived natural products according to their mechanism of action on mitochondria in terms of regulating biogenesis, fusion, fission, bioenergetics, oxidative stress, calcium homeostasis, membrane potential, and mitochondrial DNA stability, as well as repairing damaged mitochondria. In addition, we discuss the potential perspectives and challenges in developing plant-derived natural products to target mitochondria, highlighting the clinical value of phytochemicals as feasible candidates for future neurotherapeutics.

Celastrol targeting Nedd4 reduces Nrf2-mediated oxidative stress in astrocytes after ischemic stroke

Stroke is the second leading cause of death worldwide, and oxidative stress plays a crucial role. Celastrol exhibits strong antioxidant properties in several diseases; however, whether it can affect oxidation in cerebral ischemic-reperfusion injury (CIRI) remains unclear. This study aimed to determine whether celastrol could reduce oxidative damage during CIRI and to elucidate the underlying mechanisms. Here, we found that celastrol attenuated oxidative injury in CIRI by upregulating nuclear factor E2-related factor 2 (Nrf2). Using alkynyl-tagged celastrol and liquid chromatography-tandem mass spectrometry, we showed that celastrol directly bound to neuronally expressed developmentally downregulated 4 (Nedd4) and then released Nrf2 from Nedd4 in astrocytes. Nedd4 promoted the degradation of Nrf2 through K48-linked ubiquitination and thus contributed to astrocytic reactive oxygen species production in CIRI, which was significantly blocked by celastrol. Furthermore, by inhibiting oxidative stress and astrocyte activation, celastrol effectively rescued neurons from axon damage and apoptosis. Our study uncovered Nedd4 as a direct target of celastrol, and that celastrol exerts an antioxidative effect on astrocytes by inhibiting the interaction between Nedd4 and Nrf2 and reducing Nrf2 degradation in CIRI.

On the Chemical and Biological Characteristics of Multifunctional Compounds for the Treatment of Parkinson's Disease

Protein aggregation, mitochondrial dysfunction, iron dyshomeostasis, increased oxidative damage and inflammation are pathognomonic features of Parkinson's disease (PD) and other neurodegenerative disorders characterized by abnormal iron accumulation. Moreover, the existence of positive feed-back loops between these pathological components, which accelerate, and sometimes make irreversible, the neurodegenerative process, is apparent. At present, the available treatments for PD aim to relieve the symptoms, thus improving quality of life, but no treatments to stop the progression of the disease are available. Recently, the use of multifunctional compounds with the capacity to attack several of the key components of neurodegenerative processes has been proposed as a strategy to slow down the progression of neurodegenerative processes. For the treatment of PD specifically, the necessary properties of new-generation drugs should include mitochondrial destination, the center of iron-reactive oxygen species interaction, iron chelation capacity to decrease iron-mediated oxidative damage, the capacity to quench free radicals to decrease the risk of ferroptotic neuronal death, the capacity to disrupt α-synuclein aggregates and the capacity to decrease inflammatory conditions. Desirable additional characteristics are dopaminergic neurons to lessen unwanted secondary effects during long-term treatment, and the inhibition of the MAO-B and COMPT activities to increase intraneuronal dopamine content. On the basis of the published evidence, in this work, we review the molecular basis underlying the pathological events associated with PD and the clinical trials that have used single-target drugs to stop the progress of the disease. We also review the current information on multifunctional compounds that may be used for the treatment of PD and discuss the chemical characteristics that underlie their functionality. As a projection, some of these compounds or modifications could be used to treat diseases that share common pathology features with PD, such as Friedreich's ataxia, Multiple sclerosis, Huntington disease and Alzheimer's disease.

Acceleration of Oral Wound Healing under Diabetes Mellitus Conditions Using Bioadhesive Hydrogel

Oral wounds under diabetic conditions display a significant delay during the healing process, mainly due to oxidative stress-induced inflammatory status and abnormal immune responses. Besides, the wet and complicated dynamic environment of the oral cavity impedes stable treatment of oral wounds. To overcome these, a biomimetic hydrogel adhesive was innovatively developed based on a mussel-inspired multifunctional structure. The adhesive displays efficient adhesion and mechanical harmony on the oral mucosa through enhanced bonding in an acidic proinflammatory environment. The bioadhesive hydrogel exhibits excellent antioxidative properties by mimicking antioxidative enzymatic activities to reverse reactive oxygen species (ROS)-mediated immune disorders. Experiments on oral wounds of diabetic rats showed that this hydrogel adhesive could effectively protect against mucosal wounds and obviously shorten the inflammatory phase, thus promoting the wound-healing process. Therefore, this study offers a promising therapeutic choice with the potential to advance the clinical treatment of diabetic oral wounds.

Targeting the Nrf2 signaling pathway using phytochemical ingredients: A novel therapeutic road map to combat neurodegenerative diseases

BACKGROUND

Nuclear factor erythroid 2-related factor 2 (Nrf2) is a classical nuclear transcription factor that regulates the system's anti-oxidative stress response. The activation of Nrf2 induces the expression of antioxidant proteins and improves the system's anti-oxidative stress ability. Accumulating evidence suggests that Nrf2-centered signaling pathways may be a key pharmacological target for the treatment of neurodegenerative diseases (NDDs). However, phytochemicals as new therapeutic agents against NDDs have not been clearly delineated.

PURPOSE

To review the therapeutic effects of phytochemical ingredients on NDDs by activating Nrf2 and reducing oxidative stress injury.

METHODS

A comprehensive search of published articles was performed using various literature databases including PubMed, Google Scholar, and China National Knowledge Infrastructure. The search terms included "Nrf2", "phytochemical ingredients", "natural bioactive agents", "neurodegenerative diseases", "Antioxidant", "Alzheimer's disease", "Parkinson's disease", "Huntington's disease", "amyotrophic lateral sclerosis" "multiple sclerosis", "toxicity", and combinations of these keywords. A total of 769 preclinical studies were retrieved until August 2022, and we included 39 of these articless on phytochemistry, pharmacology, toxicology and other fields.

RESULTS

Numerous in vivo and in vitro studies showed that phytochemical ingredients could act as an Nrf2 activator in the treatment of NDDs through the antioxidant defense mechanism. These phytochemical ingredients, such as salidroside, naringenin, resveratrol, sesaminol, ellagic acid, ginsenoside Re, tanshinone I, sulforaphane, curcumin, naringin, tetramethylpyrazine, withametelin, magnolol, piperine, and myricetin, had the potential to improve Nrf2 signaling, thereby combatting NDDs.

CONCLUSION

As Nrf2 activators, phytochemical ingredients may provide a novel potential strategy for the treatment of NDDs. Here, we reviewed the interaction between phytochemical ingredients, Nrf2, and its antioxidant damaging pathway in NDDs and explored the advantages of phytochemical ingredients in anti-oxidative stress, which provides a reliable basis for improving the treatment of NDDs. However, further clinical trials are needed to determine the safety and efficacy of Nrf2 activators for NDDs.

HOTAIRM1 knockdown reduces MPP+-induced oxidative stress injury of SH-SY5Y cells by activating the Nrf2/HO-1 pathway

Objective

Parkinson's disease (PD) is the second most common neurodegenerative disease with complex pathogenesis. Although HOXA transcript antisense RNA myeloid-specific 1 (HOTAIRM1) is upregulated in PD, its exact role in HOTAIRM1 is seldom reported. The purpose of this study is to research the effect of HOTAIRM1 on 1-methyl-4-phenylpyridonium (MPP⁺)-induced cytotoxicity and oxidative stress in SH-SY5Y cells.

Methods

SH-SY5Y cells were treated with MPP⁺ at various concentrations or time points to induce SH-SY5Y cytotoxicity, so as to determine the optimal MPP⁺ concentration and time point. HOTAIRM1 expression upon MPP⁺ treatment was analyzed through qRT-PCR. Next, HOTAIRM1 was downregulated to observe the variance of SH-SY5Y cell viability, apoptosis, oxidative stress-related indexes, and protein levels of the Nrf2/HO-1 pathway. In addition, rescue experiments were carried out to assess the role of Nrf2 silencing in HOTAIRM1 knockdown on MPP⁺-induced oxidative stress in SH-SY5Y cells.

Results

MPP⁺ treatment-induced cytotoxicity and upregulated HOTAIRM1 expression in SH-SY5Y cells in a dose- and time-dependent manner. Mechanically, HOTAIRM1 knockdown enhanced cell viability, limited apoptosis, and oxidative stress, therefore protecting SH-SY5Y cells from MPP⁺-induced SH-SY5Y cytotoxicity. On the other hand, HOTAIRM1 knockdown activated the protein levels of Nrf2 and HO-1. Nrf2 silencing could counteract the neuroprotective effect of HOTAIRM1 knockdown on in vitro PD model.

Conclusion

Our data demonstrated that HOTAIRM1 knockdown could inhibit apoptosis and oxidative stress and activated the Nrf2/HO-1 pathway, therefore exerting neuroprotective effect on the PD cell model.

New models of Parkinson's like neuroinflammation in human microglia clone 3: Activation profiles induced by INF-γ plus high glucose and mitochondrial inhibitors

Microglia activation and neuroinflammation have been extensively studied in murine models of neurodegenerative diseases; however, to overcome the genetic differences between species, a human cell model of microglia able to recapitulate the activation profiles described in patients is needed. Here we developed human models of Parkinson's like neuroinflammation by using the human microglia clone 3 (HMC3) cells, whose activation profile in response to classic inflammatory stimuli has been controversial and reported only at mRNA levels so far. In fact, we showed the increased expression of the pro-inflammatory markers iNOS, Caspase 1, IL-1β, in response to IFN-γ plus high glucose, a non-specific disease stimulus that emphasized the dynamic polarization and heterogenicity of the microglial population. More specifically, we demonstrated the polarization of HMC3 cells through the upregulation of iNOS expression and nitrite production in response to the Parkinson's like stimuli, 6-hydroxidopamine (6-OHDA) and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), the latter depending on the NF-κB pathway. Furthermore, we identified inflammatory mediators that promote the pro-inflammatory activation of human microglia as function of different pathways that can simulate the phenotypic transition according to the stage of the pathology. In conclusion, we established and characterized different systems of HMC3 cells activation as in vitro models of Parkinson's like neuroinflammation.

Natural Products Targeting Hsp90 for a Concurrent Strategy in Glioblastoma and Neurodegeneration

Glioblastoma multiforme (GBM) is one of the most common aggressive, resistant, and invasive primary brain tumors that share neurodegenerative actions, resembling many neurodegenerative diseases. Although multiple conventional approaches, including chemoradiation, are more frequent in GBM therapy, these approaches are ineffective in extending the mean survival rate and are associated with various side effects, including neurodegeneration. This review proposes an alternative strategy for managing GBM and neurodegeneration by targeting heat shock protein 90 (Hsp90). Hsp90 is a well-known molecular chaperone that plays essential roles in maintaining and stabilizing protein folding to degradation in protein homeostasis and modulates signaling in cancer and neurodegeneration by regulating many client protein substrates. The therapeutic benefits of Hsp90 inhibition are well-known for several malignancies, and recent evidence highlights that Hsp90 inhibitors potentially inhibit the aggressiveness of GBM, increasing the sensitivity of conventional treatment and providing neuroprotection in various neurodegenerative diseases. Herein, the overview of Hsp90 modulation in GBM and neurodegeneration progress has been discussed with a summary of recent outcomes on Hsp90 inhibition in various GBM models and neurodegeneration. Particular emphasis is also given to natural Hsp90 inhibitors that have been evidenced to show dual protection in both GBM and neurodegeneration.

Therapeutic and Neuroprotective Effects of Bushen Jianpi Decoction on a Rotenone-Induced Rat Model of Parkinson’s Disease

Parkinson’s disease (PD) is an age-related neurodegenerative disorder characterized by the loss of dopaminergic neurons in the substantia nigra (SN) pars compacta. Dopamine (DA) replacement therapy is one of the most effective drug treatments for PD; however, long-term levodopa treatment can lead to various side effects that negatively impact the quality of life of patients. Therefore, finding safe and effective alternative drugs to treat PD is of clinical importance. The Bushen-Jianpi decoction (BSJPD) was derived from classic traditional Chinese medicine and has been shown to be effective in the treatment of PD. This study explored the effects and mechanisms of action of BSJPD in PD. In our study, rats were randomly divided into six groups: the vehicle group, rotenone (ROT) + Saline group, ROT + low-dose BSJPD group, ROT + high-dose BSJPD group, ROT + Madopar group, and ROT + low-dose BSJPD + Madopar group. Treatment was administered to the rats once a day for 28 days, and behavioral tests were assessed. Tyrosine hydroxylase (TH), catechol-O-methyltransferase (COMT), monoamine oxidase B (MAO-B), dopa decarboxylase (DDC), alpha-synuclein (α-syn), and heme oxygenase-1 (HO-1) levels were detected. Our results show that BSJPD increases the body weight of rats, improves their motor coordination, reverses decreasing TH levels in the SN, and increases the expression level of DDC and HO-1 in the striatum (ST), but it fails to affect TH levels in the ST in the PD model. In addition, BSJPD reduced the expression of MAO-B in the ST in the PD model, but it did not have a significant effect on COMT. Rather, COMT in the plasma and liver increased in the low-dose BSJPD treatment group. Upregulation of α-syn in the PD model was also observed, but BSJPD has shown no obvious effect to clear it. Our results suggest that BSJPD exhibits a therapeutic effect on PD and may play a neuroprotective role by regulating HO-1 expression and participating in the metabolic process of DA.

Mitochondrial glutamine transporter SLC1A5_var, a potential target to suppress astrocyte reactivity in Parkinson's Disease

SLC1A5 variant (SLC1A5_var) is identified as a mitochondrial glutamine transporter in cancer cells recently. However, the role of SLC1A5_var in Parkinson's disease (PD) is completely unknown. Here, we found the significant downregulation of SLC1A5_var in astrocytes and midbrain of mice treated with MPTP/MPP⁺ and LPS. Importantly, overexpression of SLC1A5_var ameliorated but knockdown of SLC1A5_var exacerbated MPTP/MPP⁺- and LPS-induced mitochondrial dysfunction. Consequently, SLC1A5_var provided beneficial effects on PD pathology including improvement of PD-like motor symptoms and rescue of dopaminergic (DA) neuron degeneration through maintaining mitochondrial energy metabolism. Moreover, SLC1A5_var reduced astrocyte reactivity via inhibition of A1 astrocyte conversion. Further investigation demonstrated that SLC1A5_var restrained the secretion of astrocytic pro-inflammatory cytokines by blunting TLR4-mediated downstream pathways. This is the first study to prove that astrocytic SLC1A5_var inhibits neuroinflammation, and rescues the loss of DA neurons and motor symptoms involved in PD progression, which provides a novel target for PD treatment.