Ion Channel and Transporter Involvement in Chemotherapy-Induced Peripheral Neurotoxicity.

The peripheral nervous system can encounter alterations due to exposure to some of the most commonly used anticancer drugs (platinum drugs, taxanes, vinca alkaloids, proteasome inhibitors, thalidomide), the so-called chemotherapy-induced peripheral neurotoxicity (CIPN). CIPN can be long-lasting or even permanent, and it is detrimental for the quality of life of cancer survivors, being associated with persistent disturbances such as sensory loss and neuropathic pain at limb extremities due to a mostly sensory axonal polyneuropathy/neuronopathy. In the state of the art, there is no efficacious preventive/curative treatment for this condition. Among the reasons for this unmet clinical and scientific need, there is an uncomplete knowledge of the pathogenetic mechanisms. Ion channels and transporters are pivotal elements in both the central and peripheral nervous system, and there is a growing body of literature suggesting that they might play a role in CIPN development. In this review, we first describe the biophysical properties of these targets and then report existing data for the involvement of ion channels and transporters in CIPN, thus paving the way for new approaches/druggable targets to cure and/or prevent CIPN.

Exploring Cr(VI)-induced blood-brain barrier injury and neurotoxicity in zebrafish and snakehead fish, and inhibiting toxic effects of astaxanthin.

Cr(VI) is a common hazardous heavy metal contaminant that seriously endangers human and aquatic animal health. GPX4 was the key enzyme that reduces heavy metal toxicity through inhibiting ferroptosis pathway. Astaxanthin was GPX4 activator that can weaken biological toxicity induced by Cr(VI) exposure. The present study was conducted to evaluate the major role of GPX4 in astaxanthin protects Cr(VI)-induced oxidative damage, blood-brain barrier injury and neurotoxicity in brain-liver axis through inhibiting ferroptosis pathway. In the current study, astaxanthin intervention can effectively alleviate Cr(VI)-induced oxidative stress, blood-brain barrier damage, and neurotoxicity. GPX4 plays a major role in mediating astaxanthin nutritional intervention to reduce ROS and liver non-heme iron accumulation, which would contribute to the reduction of ferroptosis. Meanwhile, astaxanthin maintains the stability of transport receptors and protein macromolecules such as TMEM163, SLC7A11, SLC3A2, FPN1 and GLUT1 in the brain liver axis, promoting substance exchange and energy supply. Moreover, astaxanthin alleviates Cr(VI)-induced neurotoxicity by promoting tight protein expression and reducing blood-brain barrier permeability.

An exploratory study on the ability of manganese to supplement rotenone neurotoxicity in rats.

Parkinson's disease (PD) is a complex disorder, primarily of idiopathic origin, with environmental stressors like rotenone and manganese linked to its development. This study explores their potential interaction and resulting neurotoxicity, aiming to understand how environmental factors contribute to PD. In an eight-day experiment, male Wistar rats weighing 280-300 g were subjected to rotenone, manganese, or a combination of both. Various parameters were assessed, including body weight, behavior, serum markers, tissue damage, protein levels (tyrosine hydroxylase, Dopamine- and cAMP-regulated neuronal phosphoprotein -DARPP-32-, and α-synuclein), and mitochondrial function. Manganese heightened rotenone's impact on reducing food intake without causing kidney or liver dysfunction. However, the combined exposure intensified neurotoxicity, which was evident in augmented broken nuclei and decreased tyrosine hydroxylase and DARPP-32 levels in the striatum. While overall mitochondrial function was preserved, co-administration reduced complex IV activity in the midbrain and liver. In conclusion, our findings revealed a parallel toxic effect induced by rotenone and manganese. Notably, while these substances do not target the same dopaminergic regions, a notable escalation in toxicity is evident in the striatum, the brain region where their toxic effects converge. This study highlights the need for further exploration regarding the interaction of environmental factors and their possible impact on the etiology of PD.

The potential role of Tirzepatide as adjuvant therapy in countering colistin-induced nephro and neurotoxicity in rats via modulation of PI3K/p-Akt/GSK3-ß/NF-kB p65 hub, shielding against oxidative and endoplasmic reticulum stress, and activation of p-CREB/BDNF/TrkB cascade.

Although colistin has a crucial antibacterial activity in treating multidrug-resistant gram-negative bacteria strains; it exhibited renal and neuronal toxicities rendering its use a challenge. Previous studies investigated the incretin hormones either glucose-dependent insulinotropic polypeptide (GIP) or glucagonlike peptide-1 (GLP-1) for their neuroprotective and nephroprotective effectiveness. The present study focused on investigating Tirzepatide (Tirze), a dual GLP-1/GIP agonist, as an adjuvant therapy in the colistin treatment protocol for attenuating its renal and neuronal complications. Rats were divided into; The normal control group, the colistin-treated group received colistin (300,000 IU/kg/day for 7 days; i.p.). The Tirze-treated group received Tirze (1.35 mg/kg on the 1,4,7thdays; s.c.) and daily colistin. Tirze effectively enhanced histopathological alterations, renal function parameters, and locomotor activity in rats. Tirze mechanistically acted via modulating various signaling axes evolved under the insult of phosphatidylinositol 3-kinases (PI3K)/phosphorylated protein kinase-B (p-Akt)/ glycogen synthase kinase (GSK)3-ß hub causing mitigation of nuclear factor (NF)-κB (NF-κB) / tumor necrosis factor-α (TNF-α), increment of nuclear factor erythroid 2-related factor 2 (Nrf2)/ glutathione (GSH), downregulation of ER stress-related biomarkers (activation transcription factor 4 (ATF4) and C/EBP homologous protein (CHOP)), antiapoptotic effects coupling with reduction of glial fibrillary acidic protein (GFAP) immunoreactivity and enhancement of phosphorylated c-AMP response element-binding (p-CREB) / brain-derived neurotrophic factor (BDNF)/tyrosine kinase B (TrkB) neuroprotective pathway. Briefly, Tirze exerts a promising role as adjuvant therapy in the colistin treatment protocol for protection against colistin's nephro- and neurotoxicity according to its anti-inflammatory, antioxidant, and antiapoptotic impacts besides its ability to suppress ER stress-related biomarkers.

Metabolomics analysis reveals characteristic metabolites in different levels of oxaliplatin-induced neurotoxicity.

Oxaliplatin (L-OHP), a third-generation platinum-based anti-tumor drug, finds widespread application in the first-line treatment of metastatic colorectal cancer. Despite its efficacy, the drug's usage is curtailed by a litany of side effects, with L-OHP-induced peripheral neuropathy (OIPN) being the most debilitating. This condition can be classified into varying degrees of severity. Employing serum metabolomics, a high-sensitivity, high-throughput technique, holds promise as a method to identify biomarkers for clinical assessment and monitoring of OIPN patients across different severity levels. In our study, we analyzed serum metabolites in patients with different OIPN levels using ultra-performance liquid chromatography-high resolution mass spectrometry. By employing statistical analyses and pathway enrichment studies, we aimed to identify potential biomarkers and metabolic pathways. Our findings characterized the serum metabolic profiles of patients with varying OIPN levels. Notably, pathway analysis revealed a significant correlation with lipid metabolism, amino acid metabolism, and energy metabolism. Multivariate statistical analysis and receiver operator characteristic curve evaluation pointed to anhalamine and glycochenodeoxycholic acid as potential biomarkers for OIPN C and A, which suggest that serum metabolomics may serve as a potent tool for exploring the metabolic status of patients suffering from diverse diseases and for discovering novel biomarkers.

Glycyrrhizic Acid Alleviates Semen Strychni-Induced Neurotoxicity Through the Inhibition of HMGB1 Phosphorylation and Inflammatory Responses.

The neurotoxicity of Semen Strychni has been reported recently in several clinical cases. Therefore, this study was conducted to investigate the role of HMGB1 in a model of neurotoxicity induced by Semen Strychni and to assess the potential alleviating effects of glycyrrhizic acid (GA), which is associated with the regulation of HMGB1 release. Forty-eight SD rats were intraperitoneally injected with Semen Strychni extract (175 mg/kg), followed by oral administration of GA (50 mg/kg) for four days. After treatment of SS and GA, neuronal degeneration, apoptosis, and necrosis were observed via histopathological examination. Inflammatory cytokines (TNF-α and IL-1ß), neurotransmitter associated enzymes (MAO and AChE), serum HMGB1, nuclear and cytoplasmic HMGB1/ph-HMGB1, and the interaction between PP2A, PKC, and HMGB1 were evaluated. The influence of the MAPK pathway was also examined. As a result, this neurotoxicity was characterized by neuronal degeneration and apoptosis, the induction of pro-inflammatory cytokines, and a reduction in neurotransmitter-metabolizing enzymes. In contrast, GA treatment significantly ameliorated the abovementioned effects and alleviated nerve injury. Furthermore, Semen Strychni promoted HMGB1 phosphorylation and its translocation between the nucleus and cytoplasm, thereby activating the NF-κB and MAPK pathways, initiating various inflammatory responses. Our experiments demonstrated that GA could partially reverse these effects. In summary, GA acid alleviated Semen Strychni-induced neurotoxicity, possibly by inhibiting HMGB1 phosphorylation and preventing its release from the cell.

Relationship between the cGAS-STING and NF-κB pathways-role in neurotoxicity.

Neurotoxicity can cause a range of symptoms and disorders in humans, including neurodegenerative diseases, neurodevelopmental disorders, nerve conduction abnormalities, neuroinflammation, autoimmune disorders, and cognitive deficits. The cyclic guanosine-adenosine synthase (cGAS)-stimulator of interferon genes (STING) pathway and NF-κB pathway are two important signaling pathways involved in the innate immune response. The cGAS-STING pathway is activated by the recognition of intracellular DNA, which triggers the production of type I interferons and pro-inflammatory cytokines, such as tumor necrosis factor, IL-1ß, and IL-6. These cytokines play a role in oxidative stress and mitochondrial dysfunction in neurons. The NF-κB pathway is activated by various stimuli, such as bacterial lipopolysaccharide, viral particle components, and neurotoxins. NF-κB activation may lead to the production of pro-inflammatory cytokines, which promote neuroinflammation and cause neuronal damage. A potential interaction exists between the cGAS-STING and NF-κB pathways, and NF-κB activation blocks STING degradation by inhibiting microtubule-mediated STING transport. This review examines the progress of research on the roles of these pathways in neurotoxicity and their interrelationships. Understanding the mechanisms of these pathways will provide valuable therapeutic insights for preventing and controlling neurotoxicity.

Sevoflurane causes neurotoxicity and cognitive impairment by regulating Hippo signaling pathway-mediated ferroptosis via upregulating PRKCD.

BACKGROUND: Sevoflurane (SEV) has been found to induce neurotoxicity and cognitive impairment, leading to the development of degenerative diseases. Protein kinase C delta (PRKCD) is upregulated in the hippocampus of SEV-treated mice and may be related to SEV-related neurotoxicity. However, the underlying molecular mechanisms by which SEV mediates neurotoxicity via PRKCD remain unclear. METHODS: Normal mice and PRKCD knockout (KO) mice were exposed to SEV. Hippocampal neurons were isolated from mice hippocampal tissues. H&E staining was used for pathological morphology of hippocampal tissues, and NISSL staining was used to analyze the number of hippocampal neurons. The mRNA and protein levels were determined using quantitative real-time PCR, western blot, immunofluorescence staining and immunohistochemical staining. The mitochondrial microstructure was observed by transmission electron microscopy. Cell viability was detected by cell counting kit 8 assay, and ferroptosis was assessed by detecting related marker levels. The cognitive ability of mice was assessed by morris water maze test. And the protein levels of PRKCD, ferroptosis-related markers and Hippo pathway-related markers were examined by western bolt. RESULTS: SEV increased PRKCD expression and ferroptosis in hippocampal tissues of mice. Also, SEV promoted mouse hippocampal neuron injury by inducing ferroptosis via upregulating PRKCD expression. Knockout of PRKCD alleviated SEV-induced neurotoxicity and cognitive impairment in mice, and relieved SEV-induced ferroptosis in hippocampal neurons. PRKCD could inhibit the activity of Hippo pathway, and its knockdown also overturned SEV-mediated ferroptosis by activating Hippo pathway. CONCLUSION: SEV could induce neurotoxicity and cognitive impairment by promoting ferroptosis via inactivating Hippo pathway through increasing PRKCD expression.

Quetiapine attenuates cadmium neurotoxicity by suppressing oxidative stress, inflammation, and pyroptosis.

BACKGROUND: Cadmium (Cd) is a heavy metal with extremely harmful toxic effects on the brain. Quetiapine (QTP) has unique neuroprotective effects with anti-inflammatory and antioxidant actions. However, its neuroprotective effect against Cd-induced neurotoxicity has not been previously studied. METHODS: QTP was administered in 10 and 20 mg/kg doses, while Cd was given in a dose of 6.5 mg/kg. RESULTS: In our study, QTP dose-dependently attenuated neuronal injury by downregulating p-tau and ß-amyloid. QTP potently attenuates histological abrasions induced by Cd. QTP counteracted oxidative injury by decreasing neuronal MDA and increased GSH levels mediated by downregulating Keap1 and upregulating Nrf2 and HO-1. QTP mitigated inflammation by decreasing MPO and NO2 and neuronal cytokines TNF-α and IL-1ß and upregulating IL-10 levels mediated by NF-κB downregulation. Additionally, QTP counteracted Cd-induced pyroptosis by downregulating caspase-1, ASC, and NLRP3 protein levels. CONCLUSION: In conclusion, QTP mitigates neurotoxicity induced by Cd through suppression of inflammation, pyroptosis, and oxidative stress by controlling the NF-κB, Keap1/Nrf2, and pyroptosis signals.

ZLN005 alleviates PBDE-47 induced impairment of mitochondrial translation and neurotoxicity through PGC-1α/ERRα axis.

Recent studies are identified the mitochondria as critical targets of 2, 2', 4, 4'-tetrabromodiphenyl ether (PBDE-47) induced neurotoxicity. This study aimed at examining the impact of PBDE-47 exposure on mitochondrial translation, and its subsequent effect on PBDE-47 neurotoxicity. The Sprague-Dawley (SD) rat model and neuroendocrine pheochromocytoma (PC12) cells were adopted for the measurements of mitochondrial ATP levels, mitochondrial translation products, and expressions of important mitochondrial regulators, such as required meiotic nuclear division 1 (RMND1), estrogen-related receptor α (ERRα), and peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α). To delve into the role of PGC-1α/ERRα axis in mitochondrial translation, 2-(4-tert-butylphenyl) benzimidazole (ZLN005) was employed. Both cellular and animal model results shown that PBDE-47 impeded PGC-1α/ERRα axis and mitochondrial translation. PBDE-47 suppressed mitochondrial function in rat hippocampus and PC12 cells by decreasing relative mitochondrial DNA (mtDNA) content, mitochondrial translation products, and mitochondrial ATP levels. Particularly, ZLN005 reversed PBDE-47 neurotoxicity by enhancing mitochondrial translation through activation of PGC-1α/ERRα axis, yet suppressing PGC-1α with siRNA attenuates its neuroprotective effect in vitro. In conclusion, this work highlights the importance of mitochondrial translation in PBDE-47 neurotoxicity by presenting results from cellular and animal models and suggests a potential therapeutic approach through activation of PGC-1α/ERRα axis. ENVIRONMENTAL IMPLICATION: PBDEs have attracted extensive attention because of their high lipophilicity, persistence, and detection levels in various environmental media. Increasing evidence has shown that neurodevelopmental disorders in children are associated with PBDE exposure. Several studies have also found that perinatal PBDE exposure can cause long-lasting neurobehavioral abnormalities in experimental animals. Our recent studies have also demonstrated the impact of PBDE-47 exposure on mitochondrial biogenesis and dynamics, leading to memory and neurobehavioral deficits. Therefore, we explore whether the pathological mechanism of PBDE-47-induced neurotoxicity involves the regulation of mitochondrial translation through the PGC-1α/ERRα axis.

Decoding the neurotoxic effects of propofol: insights into the RARα-Snhg1-Bdnf regulatory cascade.

The potential neurotoxic effects of propofol, an extensively utilized anesthetic, underline the urgency to comprehend its influence on neuronal health. Insights into the role of the retinoic acid receptor-α, small nucleolar RNA host gene 1, and brain-derived neurotrophic factor (RARα-Snhg1-Bdnf) network can offer significant advancements in minimizing these effects. The study targets the exploration of the RARα and Snhg1 regulatory network's influence on Bdnf expression in the realm of propofol-induced neurotoxicity. Harnessing the Gene Expression Omnibus (GEO) database and utilizing JASPAR and RNA-Protein Interaction Prediction (RPISeq) database for projections, the study embarks on an in-depth analysis employing both in vitro and in vivo models. The findings draw a clear link between propofol-induced neurotoxicity and the amplification of RAR signaling pathways, impacting hippocampal development and apoptosis and leading to increased RARα and Snhg1 and decreased Bdnf. Propofol is inferred to accentuate neurotoxicity by heightening RARα and Snhg1 interactions, culminating in Bdnf suppression.NEW & NOTEWORTHY This study aimed to decode propofol's neurotoxic effects on the regulatory cascade, provide insights into the RARα-Snhg1-Bdnf interaction, apply extensive validation techniques, provide a detailed analysis and exploration of propofol's neurotoxicity, and offer a comprehensive approach to understanding molecular interactions.

TXNIP knockdown protects rats against bupivacaine-induced spinal neurotoxicity via the inhibition of oxidative stress and apoptosis.

Bupivacaine (BUP) is an anesthetic commonly used in clinical practice that when used for spinal anesthesia, might exert neurotoxic effects. Thioredoxin-interacting protein (TXNIP) is a member of the α-arrestin protein superfamily that binds covalently to thioredoxin (TRX) to inhibit its function, leading to increased oxidative stress and activation of apoptosis. The role of TXNIP in BUP-induced oxidative stress and apoptosis remains to be elucidated. In this context, the present study aimed to explore the effects of TXNIP knockdown on BUP-induced oxidative stress and apoptosis in the spinal cord of rats and in PC12 cells through the transfection of adeno-associated virus-TXNIP short hairpin RNA (AAV-TXNIP shRNA) and siRNA-TXNIP, respectively. In vivo, a rat model of spinal neurotoxicity was established by intrathecally injecting rats with BUP. The BUP + TXNIP shRNA and the BUP + Control shRNA groups of rats were injected with an AAV carrying the TXNIP shRNA and the Control shRNA, respectively, into the subarachnoid space four weeks prior to BUP treatment. The Basso, Beattie & Bresnahan (BBB) locomotor rating score, % MPE of TFL, H&E staining, and Nissl staining analyses were conducted. In vitro, 0.8 mM BUP was determined by CCK-8 assay to establish a cytotoxicity model in PC12 cells. Transfection with siRNA-TXNIP was carried out to suppress TXNIP expression prior to exposing PC12 cells to BUP. The results revealed that BUP effectively induced neurological behavioral dysfunction and neuronal damage and death in the spinal cord of the rats. Similarly, BUP triggered cytotoxicity and apoptosis in PC12 cells. In addition, treated with BUP both in vitro and in vivo exhibited upregulated TXNIP expression and increased oxidative stress and apoptosis. Interestingly, TXNIP knockdown in the spinal cord of rats through transfection of AAV-TXNIP shRNA exerted a protective effect against BUP-induced spinal neurotoxicity by ameliorating behavioral and histological outcomes and promoting the survival of spinal cord neurons. Similarly, transfection with siRNA-TXNIP mitigated BUP-induced cytotoxicity in PC12 cells. In addition, TXNIP knockdown mitigated the upregulation of ROS, MDA, Bax, and cleaved caspase-3 and restored the downregulation of GSH, SOD, CAT, GPX4, and Bcl2 induced upon BUP exposure. These findings suggested that TXNIP knockdown protected against BUP-induced spinal neurotoxicity by suppressing oxidative stress and apoptosis. In summary, TXNIP could be a central signaling hub that positively regulates oxidative stress and apoptosis during neuronal damage, which renders TXNIP a promising target for treatment strategies against BUP-induced spinal neurotoxicity.

Elevated intracellular Ca2+ functions downstream of mitodysfunction to induce Wallerian-like degeneration and necroptosis in organophosphorus-induced delayed neuropathy.

Neurotoxic organophosphorus compounds can induce a type of delayed neuropathy in humans and sensitive animals, known as organophosphorus-induced delayed neuropathy (OPIDN). OPIDN is characterized by axonal degeneration akin to Wallerian-like degeneration, which is thought to be caused by increased intra-axonal Ca2+ concentrations. This study was designed to investigate that deregulated cytosolic Ca2+ may function downstream of mitodysfunction in activating Wallerian-like degeneration and necroptosis in OPIDN. Adult hens were administrated a single dosage of 750 mg/kg tri-ortho-cresyl phosphate (TOCP), and then sacrificed at 1 day, 5 day, 10 day and 21 day post-exposure, respectively. Sciatic nerves and spinal cords were examined for pathological changes and proteins expression related to Wallerian-like degeneration and necroptosis. In vitro experiments using differentiated neuro-2a (N2a) cells were conducted to investigate the relationship among mitochondrial dysfunction, Ca2+ influx, axonal degeneration, and necroptosis. The cells were co-administered with the Ca2+-chelator BAPTA-AM, the TRPA1 channel inhibitor HC030031, the RIPK1 inhibitor Necrostatin-1, and the mitochondrial-targeted antioxidant MitoQ along with TOCP. Results demonstrated an increase in cytosolic calcium concentration and key proteins associated with Wallerian degeneration and necroptosis in both in vivo and in vitro models after TOCP exposure. Moreover, co-administration with BATPA-AM or HC030031 significantly attenuated the loss of NMNAT2 and STMN2 in N2a cells, as well as the upregulation of SARM1, RIPK1 and p-MLKL. In contrast, Necrostatin-1 treatment only inhibited the TOCP-induced elevation of p-MLKL. Notably, pharmacological protection of mitochondrial function with MitoQ effectively alleviated the increase in intracellular Ca2+ following TOCP and mitigated axonal degeneration and necroptosis in N2a cells, supporting mitochondrial dysfunction as an upstream event of the intracellular Ca2+ imbalance and neuronal damage in OPIDN. These findings suggest that mitochondrial dysfunction post-TOCP intoxication leads to an elevated intracellular Ca2+ concentration, which plays a pivotal role in the initiation and development of OPIDN through inducing SARM1-mediated axonal degeneration and activating the necroptotic signaling pathway.

Nanoplastics aggravated TDCIPP-induced transgenerational developmental neurotoxicity in zebrafish depending on the involvement of the dopamine signaling pathway.

Plastics pose a hazard to the environment. Although plastics have toxicity, microplastics (MPs) and nanoplastics (NPs) are capable of interacting with the rest pollutants in the environment, so they serve as the carriers and interact with organic pollutants to modulate their toxicity, thus resulting in unpredictable ecological risks. PS-NPs and TDCIPP were used expose from 2 h post-fertilization (hpf) to 150 days post-fertilization (dpf) to determine the bioaccumulation of tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) and its potential effects on neurodevelopment in F1 zebrafish (Danio rerio) offspring under the action of polystyrene nano plastics (PS-NPs). The exposure groups were assigned to TDCIPP (0, 0.4, 2 or 10 µg/L) alone group and the PS-NPs (100 µg/L) and TDCIPP co-exposed group. F1 embryos were collected and grown in clean water to 5 dpf post-fertilization. PS-NPs facilitated the bioaccumulation of TDCIPP in the gut, gill, head，gonad and liver of zebrafish in a sex-dependent manner and promoted the transfer of TDCIPP to their offspring, thus contributing to PS-NPs aggravated the inhibition of offspring development and neurobehavior of TDCIPP-induced. In comparison with TDCIPP exposure alone, the combination could notably down-regulate the levels of the dopamine neurotransmitter, whereas the levels of serotonin or acetylcholine were not notably different. This result was achieved probably because PS-NPs interfered with the TDCIPP neurotoxic response of zebrafish F1 offspring not through the serotonin or acetylcholine neurotransmitter pathway. The increased transfer of TDCIPP to the offspring under the action of PS-NPs increased TDCIPP-induced transgenerational developmental neurotoxicity, which was proven by a further up-regulation/down-regulation the key gene and protein expression related to dopamine synthesis, transport, and metabolism in F1 larvae, in contrast to TDCIPP exposure alone. The above findings suggested that dopaminergic signaling involvement could be conducive to the transgenerational neurodevelopmental toxicity of F1 larval upon parental early co-exposure to PS-NPs and TDCIPP.

Polyglutamine disorders: Pathogenesis and potential drug interventions.

Polyglutamine/poly(Q) diseases are a group nine hereditary neurodegenerative disorders caused due to abnormally expanded stretches of CAG trinucleotide in functionally distinct genes. All human poly(Q) diseases are characterized by the formation of microscopically discernable poly(Q) positive aggregates, the inclusion bodies. These toxic inclusion bodies are responsible for the impairment of several cellular pathways such as autophagy, transcription, cell death, etc., that culminate in disease manifestation. Although, these diseases remain largely without treatment, extensive research has generated mounting evidences that various events of poly(Q) pathogenesis can be developed as potential drug targets. The present review article briefly discusses the key events of disease pathogenesis, model system-based investigations that support the development of effective therapeutic interventions against pathogenesis of human poly(Q) disorders, and a comprehensive list of pharmacological and bioactive compounds that have been experimentally shown to alleviate poly(Q)-mediated neurotoxicity. Interestingly, due to the common cause of pathogenesis, all poly(Q) diseases share etiology, thus, findings from one disease can be potentially extrapolated to other poly(Q) diseases as well.

Parkinson's disease-derived α-synuclein assemblies combined with chronic-type inflammatory cues promote a neurotoxic microglial phenotype.

Parkinson's disease (PD) is a common age-related neurodegenerative disorder characterized by the aggregation of α-Synuclein (αSYN) building up intraneuronal inclusions termed Lewy pathology. Mounting evidence suggests that neuron-released αSYN aggregates could be central to microglial activation, which in turn mounts and orchestrates neuroinflammatory processes potentially harmful to neurons. Therefore, understanding the mechanisms that drive microglial cell activation, polarization and function in PD might have important therapeutic implications. Here, using primary microglia, we investigated the inflammatory potential of pure αSYN fibrils derived from PD patients. We further explored and characterized microglial cell responses to a chronic-type inflammatory stimulation combining PD patient-derived αSYN fibrils (FPD), Tumor necrosis factor-α (TNFα) and prostaglandin E2 (PGE2) (TPFPD). We showed that FPD hold stronger inflammatory potency than pure αSYN fibrils generated de novo. When combined with TNFα and PGE2, FPD polarizes microglia toward a particular functional phenotype departing from FPD-treated cells and featuring lower inflammatory cytokine and higher glutamate release. Whereas metabolomic studies showed that TPFPD-exposed microglia were closely related to classically activated M1 proinflammatory cells, notably with similar tricarboxylic acid cycle disruption, transcriptomic analysis revealed that TPFPD-activated microglia assume a unique molecular signature highlighting upregulation of genes involved in glutathione and iron metabolisms. In particular, TPFPD-specific upregulation of Slc7a11 (which encodes the cystine-glutamate antiporter xCT) was consistent with the increased glutamate response and cytotoxic activity of these cells toward midbrain dopaminergic neurons in vitro. Together, these data further extend the structure-pathological relationship of αSYN fibrillar polymorphs to their innate immune properties and demonstrate that PD-derived αSYN fibrils, TNFα and PGE2 act in concert to drive microglial cell activation toward a specific and highly neurotoxic chronic-type inflammatory phenotype characterized by robust glutamate release and iron retention.

Benefits of rutin on mitochondrial function and inflammation in an aluminum-induced neurotoxicity rat model: Potential interest for the prevention of neurodegeneration.

Rutin, a phenolic compound, exhibits a diverse range of biological properties, including antioxidant, anti-inflammatory, and antimicrobial effects. In this study, we aimed to investigate the potential of rutin, a naturally occurring plant bioactive molecule, to mitigate the neurotoxic effects induced by aluminum chloride (AlCl3). Over a period of 6 weeks, rats were intraperitoneally injected with AlCl3 at a weekly dose of 60 mg/kg, while rutin treatment was administered orally via gavage at a daily dose of 30 mg/kg. AlCl3 exposure resulted in a significant increase lipid peroxidation (LPO) by 316.24%, nitrate levels by 504.14%, and tumor necrosis factor-alpha (TNF-α) levels by 93.82% in brain mitochondria. Additionally, AlCl3 exposure led to a reduction in glutathione levels and the activity of antioxidant enzymes, including superoxide dismutase (SOD) by 19.74%, glutathione peroxidase (GPx) by 44.76%, and catalase by 50.50%. There was also a significant decline in the activity of mitochondrial complex enzymes. In contrast, rutin treatment significantly enhanced the activity of antioxidant enzymes while concurrently reducing lipid peroxidation levels in rats. Specifically, rutin administration exerted a modulatory effect on the inflammatory response triggered by aluminum exposure, effectively suppressing the excessive production of nitrate and TNF-α. These findings highlight the potential of rutin as an effective therapeutic strategy in mitigating and combating neuro-inflammation and oxidative stress associated with aluminum-induced toxicity, thereby effectively restoring mitochondrial function.

Metabolomic modelling and neuroprotective effects of carvacrol against acrylamide toxicity in rat's brain and sciatic nerve.

The study aimed to investigate the harmful effects of acrylamide (AA), which forms in carbohydrate-rich foods at temperatures above 120°C, on the central and peripheral nervous systems and to evaluate the potential neuroprotective effects of carvacrol (CRV). Male Wistar Albino rats were subjected to AA (40 mg/kg/bw/day) and CRV (50 mg/kg/bw/day) for 15 days. Following the last administration, evaluations revealed disrupted gait, heightened thermal sensitivity and altered paw withdrawal thresholds in AA-exposed rats. Notably, AA reduced glutathione (GSH) and raised malondialdehyde (MDA) levels in both brain and sciatic nerve tissues. AA raised nuclear factor erythroid 2-related factor 2 (Nrf2), caspase 3 and nuclear factor κB (NF-κB) gene expressions while decreasing NR4A2. CRV co-administration mitigated gait abnormalities, elevated GSH levels and lowered MDA levels in both tissues. CRV also modulated gene expression, reducing Nrf2 and NF-κB while increasing NR4A2. Histopathological signs of AA-induced neurodegeneration and elevated glial fibrillary acidic protein levels observed in brain and sciatic nerve tissues were rectified with simultaneous administration of CRV, thereby demonstrating neuroprotective efficacy in both regions. This study is pioneering in demonstrating CRV's neuroprotective potential against AA-induced neurotoxicity in both central and peripheral nervous systems, effectively addressing limitations in the literature. In conclusion, the study revealed AA-induced neurodegeneration in the brain and sciatic nerve, with CRV significantly mitigating this neurotoxicity. This novel research underscores CRV's promise as a neuroprotective agent against AA-induced adverse effects in both the central and peripheral nervous systems.

BDNF specifically expressed in hippocampal neurons is involved in methylmercury neurotoxicity resistance.

Methylmercury (MeHg) causes selective neuronal damage to cerebrocortical neurons (CCNs) in the central nervous system, but not to hippocampal neurons (HiNs), which are highly vulnerable to neurodegenerative diseases. In our previous study using cultured rat neurons, we performed a comprehensive gene expression analysis and found that the brain-derived neurotrophic factor (BDNF), a neurotrophin (NT), was specifically expressed in HiNs. Therefore, to elucidate the causal factors of MeHg toxicity resistance in HiNs, we conducted a comparative study of the protein expression and function of several NTs, including BDNF, using CCNs showing vulnerability to MeHg toxicity and HiNs showing resistance. BDNF was specifically expressed in HiNs, whereas nerve growth factor was barely detectable in either neuron type. In addition, other NTs, NT3 and NT4/5, were expressed in small but nearly equal amounts in both neuron types. Furthermore, among the various pathways involved in MeHg neurotoxicity, the p44/42 MAPK pathway was specifically activated in HiNs, even without MeHg treatment. siRNAs were used to reduce NTs in both neuron types. Only a specific reduction in BDNF attenuated the resistance to MeHg toxicity and p44/42 MAPK activation in HiNs. In addition, the external addition of BDNF and NT4/5, which act on the same tyrosine receptor kinase (Trk), TrkB, suppressed MeHg neurotoxicity in both neuron types. These results suggest that BDNF, expressed specifically in HiNs, is involved in the resistance to MeHg neurotoxicity via TrkB. Additionally, the activation of the p44/42 MAPK pathway may contribute to the inhibitory effect of BDNF on MeHg neurotoxicity.

Notoginsenoside R1 attenuates bupivacaine induced neurotoxicity by activating Jak1/Stat3/Mcl1 pathway.

Bupivacaine, a common amide local anesthetic, can provide effective analgesia or pain relief but can also cause neurotoxicity, which remains a mounting concern in clinic and animal care. However, the precise underlying mechanisms have not been fully elucidated. A natural compound, notoginsenoside R1 (NG-R1) has been reported to exhibit a neuroprotective role in stress conditions. In this study, we explored the function and mechanism of NG-R1 in alleviating bupivacaine-induced neurotoxicity in mouse hippocampal neuronal (HT-22) and mouse neuroblastoma (Neuro-2a) cell lines. Our results exhibited that NG-R1 treatment can significantly rescue the decline of cell survival induced by bupivacaine. Tunel staining and western blotting showed that NG-R1 could attenuate BPV­induced cell apoptosis. Besides, we focused on Mcl1 as a potential target as it showed opposite expression tendency in response to NG-R1 and bupivacaine exposure. Mcl1 knockdown blocked the inhibitory effect of NG-R1 on cell apoptosis against bupivacaine treatment. Intriguingly, we found that NG-R1 can upregulate Mcl1 transcription by activating Stat3 and promote its nuclear translocation. In addition, NG-R1 can also promote Jak1 phosphorylation and docking analysis provide a predicted model for interaction between NG-R1 and phosphorylated Jak1. Taken together, our results demonstrated that NG-R1 can attenuate bupivacaine induced neurotoxicity by activating Jak1/Stat3/Mcl1 pathway.