Using Rotenone to Model Parkinson's Disease in Mice: A Review of the Role of Pharmacokinetics

Discovery of potential Leonurine-based therapeutic lead MJ210 attenuates Parkinson's disease pathogenesis via NF-κB and MAPK pathways: Mechanistic insights from in vitro and in vivo rotenone models

Parkinson's disease (PD) is a common neurodegenerative disease affecting motor and non-motor functions, with no effective treatment yet discovered. Neuroprotective compounds, both natural and synthetic, show promise but face challenges such as crossing the blood-brain barrier, limited serum stability, and higher toxicity. To tackle these obstacles, we have devised an innovative design strategy inspired by the neuroprotective properties of Leonurine, widely utilized in managing neurological disorders. Through rigorous screening of our compound library, we have identified a potent therapeutic molecule (MJ210) that exhibited remarkable efficacy in bolstering neuroprotection against rotenone-induced PD models, both in vitro and in vivo. Our findings revealed that administering MJ210 significantly increased neuronal survival in the SH-SY5Y model of PD. This was achieved by preventing apoptosis, reducing reactive oxygen species, mitigating mitochondrial dysfunction, and dampening neuroinflammation via ERK1/2-P38-JNK and P65-NFκB signaling pathways. In addition, MJ210 demonstrated remarkable neuroprotective abilities in vivo by significantly enhancing dopamine biosynthesis, alleviating motor dysfunction, improving balance and coordination, and reversing depression in rotenone-induced PD rats, even outperforming L-DOPA, the current gold standard treatment for PD. Therefore, MJ210 emerges as a significantly promising therapeutic candidate for PD, offering the potential for managing both the severity and progression of this disease.

Treadmill exercise mitigates rotenone-induced neuroinflammation and α-synuclein level in a mouse model of Parkinson's disease

Parkinson's disease (PD) is the second most common neurodegenerative disorder, affecting 7-10 million people globally. It presents with motor symptoms like bradykinesia, tremors, rigidity, and postural instability, along with non-motor issues such as anxiety and mood fluctuations. PD is characterized by the progressive loss of nigrostriatal neurons, α-synuclein protein aggregation, reduced tyrosine hydroxylase level, and impaired dopamine signaling. Neuroinflammation plays a key role in PD progression, with elevated pro-inflammatory cytokines promoting M1 microglial activation, which exacerbates neurodegeneration. Conversely, anti-inflammatory cytokines such as IL-10 and IL-4 help shift microglia to the neuroprotective M2 phenotype, reducing inflammation. Animal models show an imbalance with increased M1 and reduced M2 microglia. This study explored the neuroprotective effects of treadmill exercise in a rotenone-induced PD mouse model. After 21 days of exercise, behavioral impairments improved, as shown by open field tests, Rota-rod, and footprint analysis. Exercise also reduced pro-inflammatory cytokines; TNF-α, and IL-1β levels while increasing anti-inflammatory cytokines; IL-10, and IL-4. This shift correlated with decreased α-synuclein levels and increased tyrosine hydroxylase expression, indicating reduced neurodegeneration. These findings suggest that treadmill exercise can mitigate PD symptoms and pathology by modulating neuroinflammation and restoring dopaminergic function.

Procognitive Potential of Neuroprotective Triazine 5-HT6 Receptor Antagonists Tested on Chronic Activity In Vivo in Rats: Computer-Aided Insight into the Role of Chalcogen-Differences on the Pharmacological Profile

Among serotonin receptors, the 5-HT6 subtype is an important protein target and its ligands may play a key role in the innovative treatment of cognitive disorders. This study aimed to extend the body of preclinical research on two naphthyl-derived methylpiperazine-1,3,5-triazine analogues with thioether (WA-22) or Se-ether (PPK-32) linkers, the newly described compounds having high affinity and selectivity for 5-HT6 receptors and drug-like parameters in vitro. Thus, crystallography-supported deeper insight into their chemical properties, the comparison of their neuroprotective and pharmacokinetic profiles, and especially their impact on memory disturbances after chronic administration to rats were investigated. As a result, the chronic administration of WA-22 completely reversed (+)MK-801-induced memory disturbances evaluated in the novel object recognition test (NORT) in rats. The pharmacokinetic and biochemical results support the notion that this 1,3,5-triazine 5-HT6 receptor ligand could offer a promising therapeutic tool in CNS-related disorders. The selenium compound PPK-32, with a similar range of activity at acute administration, has shown even broader neuroprotective profiles, especially at the genetic level. However, for therapeutic use, its weaker pharmacokinetics (stability), which is a probable limit for action upon chronic administration, would require improvement, e.g., by an appropriate formulation.

The multiple biological activities of hyperoside: from molecular mechanisms to therapeutic perspectives in neoplastic and non-neoplastic diseases

In recent years, hyperoside (quercetin 3-O-β-D-galactopyranoside) has garnered significant attention due to its diverse biological effects, which include vasoprotective, antioxidant, anti-inflammatory, and anti-tumor properties. Notably, hyperoside has shown remarkable potential in cancer therapy by targeting multiple mechanisms; it induces apoptosis, inhibits proliferation, blocks angiogenesis, and reduces the metastatic potential of cancer cells. Furthermore, hyperoside enhances the sensitivity of cancer cells to chemotherapy by modulating key signaling pathways. Beyond neoplastic diseases, hyperoside also presents promising therapeutic applications in managing non-cancerous conditions such as diabetes, Alzheimer's disease, and pulmonary fibrosis. This review comprehensively examines the molecular mechanisms underlying hyperoside's anti-cancer effects and highlights its role in the treatment of cancers, including lung and colorectal cancers. Additionally, it explores the latest research on hyperoside's potential in addressing non-neoplastic conditions, such as pulmonary fibrosis, diabetes, and Parkinson's disease. By summarizing current findings, this review underscores the unique therapeutic value of hyperoside and its potential as a multifunctional treatment in both neoplastic and non-neoplastic contexts.

ECHS1-NOX4 interaction suppresses rotenone-induced dopaminergic neurotoxicity through inhibition of mitochondrial ROS production

BACKGROUND

Parkinson's disease (PD) is the most common neurodegenerative movement disorder with uncleared mechanisms. Short-chain enoyl-CoA hydratase 1 (ECHS1) is a mitochondrial enzyme critical for the β-oxidation of fatty acids and ATP production. This study aims to explore the roles of ECHS1 in PD by using rotenone-induced experimental PD models.

METHODS

To evaluate the role of ECHS1 in rotenone-induced dopaminergic neurodegeneration, adeno-associated virus (AAV)-ECHS1 was stereotactically injected into the substantia nigra region of mice to overexpress ECHS1. Motor function of mice among groups was detected by rotarod test and gait analysis. Neurodegeneration, mitochondrial dysfunction and apoptosis were determined by immunohistochemistry, immunofluorescence staining, Western blot or kits, respectively.

RESULTS

The expression and activity of ECHS1 were decreased in PD mice and positive correlations between ECHS1 reduction and dopaminergic neurodegeneration were observed. Overexpression of ECHS1 by AAV delivery attenuated loss of dopaminergic neuron and motor deficits in PD mice. Mechanistically, ECHS1 attenuated rotenone-induced mitochondrial swelling and loss of cristae as well as decrease of ATP production, mitochondrial membrane potential, complex I/IV activities and oxygen consumption rate (OCR). Mitochondrial ROS (mtROS)-targeted antioxidant mito-TEMPO prevented ECHS1 silence-mediated mitochondrial dysfunction. Furthermore, we found that ECHS1 interacted with NADPH oxidase 4 (NOX4), resulting in decrease of NOX4 activation and subsequent reduction of mtROS production and mitochondrial dysfunction. Finally, inhibition of NOX4 by GLX351322 or mtROS production by mito-TEMPO greatly reduced ECHS1 silence-mediated apoptosis in rotenone-treated SH-SY5Y cells.

CONCLUSIONS

ECHS1 counteracted dopaminergic neurodegeneration through inhibition of mtROS and restoration of mitochondrial function via interaction with NOX4. Given the central role of mitochondrial dysfunction in PD pathogenesis, elucidating the role of ECHS1 holds great promise for uncovering novel therapeutic targets.

Rotenone Induces Parkinsonism with Constipation Symptoms in Mice by Disrupting the Gut Microecosystem, Inhibiting the PI3K-AKT Signaling Pathway and Gastrointestinal Motility

Parkinson's disease (PD) is one of the most common neurodegenerative diseases. Constipation is a prodromal symptom of PD. It is important to investigate the pathogenesis of constipation symptoms in PD. Rotenone has been successfully used to establish PD animal models. However, the specific mechanism of rotenone-induced constipation symptoms is not well understood. In this work, we found that constipation symptoms appeared earlier than motor impairment in mice gavaged with a low dose of rotenone (30 mg/kg·BW). Rotenone not only caused loss of dopaminergic neurons and accumulation of α-synuclein, but also significantly reduced serum 5-HT levels and 5-HTR4 in the striatum and colon. The mRNA expression of aquaporins, gastrointestinal motility factors (c-Kit, Cx43, smMLCK and MLC-3) in mouse colon was also significantly regulated by rotenone. In addition, both colon and brain showed rotenone-induced inflammation and barrier dysfunction; the PI3K/AKT pathway in the substantia nigra and colon was also significantly inhibited by rotenone. Importantly, the structure, composition and function of the gut microbiota were also significantly altered by rotenone. Some specific taxa were closely associated with motor and constipation symptoms, inflammation, and gut and brain barrier status in PD mice. Akkermansia, Staphylococcus and Lachnospiraceae_UCG-006 may play a role in exacerbating constipation symptoms, whereas Acinetobacter, Lactobacillus, Bifidobacterium, Solibacillus and Eubacterium_xylanophilum_groups may be beneficial in stimulating gastrointestinal peristalsis, maintaining motor function and alleviating inflammation and barrier damage in mice. In conclusion, low-dose rotenone can cause parkinsonism with constipation symptoms in mice by disrupting the intestinal microecosystem and inhibiting the PI3K-AKT pathway and gastrointestinal motility.

Energy metabolism in health and diseases

Energy metabolism is indispensable for sustaining physiological functions in living organisms and assumes a pivotal role across physiological and pathological conditions. This review provides an extensive overview of advancements in energy metabolism research, elucidating critical pathways such as glycolysis, oxidative phosphorylation, fatty acid metabolism, and amino acid metabolism, along with their intricate regulatory mechanisms. The homeostatic balance of these processes is crucial; however, in pathological states such as neurodegenerative diseases, autoimmune disorders, and cancer, extensive metabolic reprogramming occurs, resulting in impaired glucose metabolism and mitochondrial dysfunction, which accelerate disease progression. Recent investigations into key regulatory pathways, including mechanistic target of rapamycin, sirtuins, and adenosine monophosphate-activated protein kinase, have considerably deepened our understanding of metabolic dysregulation and opened new avenues for therapeutic innovation. Emerging technologies, such as fluorescent probes, nano-biomaterials, and metabolomic analyses, promise substantial improvements in diagnostic precision. This review critically examines recent advancements and ongoing challenges in metabolism research, emphasizing its potential for precision diagnostics and personalized therapeutic interventions. Future studies should prioritize unraveling the regulatory mechanisms of energy metabolism and the dynamics of intercellular energy interactions. Integrating cutting-edge gene-editing technologies and multi-omics approaches, the development of multi-target pharmaceuticals in synergy with existing therapies such as immunotherapy and dietary interventions could enhance therapeutic efficacy. Personalized metabolic analysis is indispensable for crafting tailored treatment protocols, ultimately providing more accurate medical solutions for patients. This review aims to deepen the understanding and improve the application of energy metabolism to drive innovative diagnostic and therapeutic strategies.

Evaluating the efficacy of vatiquinone in preclinical models of Leigh syndrome and GPX4 deficiency

BACKGROUND

Genetic mitochondrial diseases are a major challenge in modern medicine. These impact ~ 1:4,000 individuals and there are currently no effective therapies. Leigh syndrome is the most common pediatric presentation of mitochondrial disease. In humans, patients are often treated with antioxidants, vitamins, and strategies targeting energetics. The vitamin-E related compound vatiquinone (EPI-743, α-tocotrienol quinone) has been the subject of at least 19 clinical trials in the US since 2012, but the effects of vatiquinone on an animal model of mitochondrial disease have not yet been reported. Here, assessed the impact of vatiquinone in cellular assays and animal models of mitochondrial disease.

METHODS

The efficacy of vatiquinone in vitro was assessed using human fibroblasts and HEK293 cells treated with the ferroptosis inducers RSL3 and BSO + Fe(III)Citrate, the mitochondrial oxidative stress inducer paraquat, and the electron transport chain complex I inhibitor rotenone. The therapeutic potential of vatiquinone in vivo was assessed using the tamoxifen-induced mouse model for GPX4 deficiency and the Ndufs4 knockout mouse model of Leigh syndrome.

RESULTS

Vatiquinone robustly prevented death in cultured cells induced by RSL3 or BSO/iron, but had no effect on paraquat induced cell death. Vatiquinone had no impact on disease onset, progression, or survival in either the tamoxifen-inducible GPX4 deficient model or the Ndufs4(-/-) mouse model, though the drug may have reduced seizure risk.

CONCLUSIONS

Vatiquinone prevents ferroptosis, but fails to attenuate cell death induced by paraquat or rotenone and provided no significant benefit to survival in two mouse models of disease. Vatiquinone may prevent seizures in the Ndufs4(-/-) model. Our findings are consistent with recent press statements regarding clinical trial results and have implications for drug trial design and reporting in patients with rare diseases.

Sox6 and ALDH1A1 Truncation by Asparagine Endopeptidase Defines Selective Neuronal Vulnerability in Parkinson's Disease

Dopaminergic neurons in the substantia nigra pars compacta (SNpc) demonstrate regionally selective susceptibility in Parkinson's disease (PD) compared to those in the ventral tegmental area (VTA). However, the molecular mechanism for this distinct vulnerability remains unclear. Here, it is shown that Legumain, also known as asparagine endopeptidase (AEP), is activated in a subgroup of SRY-box transcription factor 6 /Aldehyde dehydrogenase 1 family member A1, (Sox6+/ALDH1A1+) neurons in the ventral tier of the SNpc and cleaves Sox6 and ALDH1A1, leading to repression of Special AT-rich sequence binding protein 1 (Satb1) that is a dimeric/tetrameric transcription factor specifically binding to AT-rich DNA sequences, and toxic dopamine metabolite accumulation. AEP cuts Sox6 and ALDH1A1 in dopaminergic neurons that project to the locus coeruleus (LC), abolishing Sox6's transcriptive and ALDH1A1's enzymatic activities. Co-expressing AEP-truncated Sox6 and ALDH1A1 fragments in 3-month-old A53T SNCA transgenic mice accelerates dopamine degeneration, whereas expressing AEP-resistant Sox6 N336A/N446A and ALDH1A1 N220A mutants alleviates rotenone-induced PD pathologies. Hence, different circuitries and intrinsic properties of dopaminergic neurons in the SNpc and VTA render differential predispositions in PD.

The neuroprotective effect of 1,25-dyhydroxyvitamin D3 (calcitriol) and probiotics on the rotenone-induced neurotoxicity model in SH-SY5Y cells

This study aimed to investigate the neuroprotective role of probiotics and 1,25-dyhydroxyvitamin D3 (calcitriol) against neurotoxicity on rotenone-induced human neuroblastoma cell line SH-SY5Y. Rotenone was administered to induce neurotoxic effects in SH-SY5Y cells. Calcitriol and probiotics were administered at different concentrations as pre- and post-treatment. The thiazolyl blue tetrazolium bromide (MTT) assay was performed to measure cell viability. Intracellular protein levels of antioxidant enzymes (protein tyrosine kinase (PTK), superoxide dismutase (SOD), glutathione peroxidase (GSH), glutathione reductase (GSR), and catalase (CAT)) were determined by the enzyme-linked immunosorbent assay (ELISA). Rotenone (150 nM) reduced (p < 0.001) cell viability compared to control cells. Single and combined pretreatments with probiotics (0.01 mg/ml, 0.05 mg/ml, and 0.1 mg/ml) and calcitriol (1.25 µM, 2.5 µM, and 5 µM) increased (p < 0.05) cell viability compared to rotenone group. In the pre- and post-treatment design, all treatment groups increased the SOD and GSH levels and decreased the GSR levels compared to rotenone. None of the pretreatments reversed the PTK levels (except probiotics: 0.01 mg/ml). Calcitriol (2.5 µM) increased the CAT levels in pretreatment design, and probiotics (0.05 mg/ml and 0.1 mg/ml) increased CAT levels in post-treatment design compared to rotenone group. Calcitriol and probiotics protect against rotenone-induced neurotoxicity in SH-SY5Y cells by decreasing reactive oxygen species (ROS) and increasing antioxidant enzyme parameters. These neuroprotective effects of calcitriol and probiotics against rotenone-induced dopaminergic neurotoxicity provide an experimental basis for their potential clinical use in the treatment of Parkinson's disease (PD).

A Review on Current Aspects of Curcumin-Based Effects in Relation to Neurodegenerative, Neuroinflammatory and Cerebrovascular Diseases

Curcumin is among the most well-studied natural substances, known for its biological actions within the central nervous system, its antioxidant and anti-inflammatory properties, and human health benefits. However, challenges persist in effectively utilising curcumin, addressing its metabolism and passage through the blood-brain barrier (BBB) in therapies targeting cerebrovascular diseases. Current challenges in curcumin's applications revolve around its effects within neoplastic tissues alongside the development of intelligent formulations to enhance its bioavailability. Formulations have been discovered including curcumin's complexes with brain-derived phospholipids and proteins, or its liposomal encapsulation. These novel strategies aim to improve curcumin's bioavailability and stability, and its capability to cross the BBB, thereby potentially enhancing its efficacy in treating cerebrovascular diseases. In summary, this review provides a comprehensive overview of molecular pathways involved in interactions of curcumin and its metabolites, and brain vascular homeostasis. This review explores cellular and molecular current aspects, of curcumin-based effects with an emphasis on curcumin's metabolism and its impact on pathological conditions, such as neurodegenerative diseases, schizophrenia, and cerebral angiopathy. It also highlights the limitations posed by curcumin's poor bioavailability and discusses ongoing efforts to surpass these impediments to harness the full therapeutic potential of curcumin in neurological disorders.

Rotenone exposure causes features of Parkinson`s disease pathology linked with muscle atrophy in developing zebrafish embryo

Parkinson's disease (PD) is associated with both genetic and environmental factors; however, sporadic forms of PD account for > 90 % of cases, and PD prevalence has doubled in the past 25 years. Depending on the importance of the environmental factors, various neurotoxins are used to induce PD both in vivo and in vitro. Unlike other neurodegenerative diseases, PD can be induced in vivo using specific neurotoxic chemicals. However, no chemically induced PD model is available because of the sporadic nature of PD. Rotenone is a pesticide that accelerates the induction of PD and exhibits the highest toxicity in fish, unlike other pesticides. Therefore, in this study, we aimed to establish a model exhibiting PD pathologies such as dysfunction of DArgic neuron, aggregation of ɑ-synuclein, and behavioral abnormalities, which are known features of PD pathology, by rotenone exposure at an environmentally relevant concentration (30 nM) in developing zebrafish embryos. Our results provide direct evidence for the association between PD and muscle degeneration by confirming rotenone-induced muscle atrophy. Therefore, we conclude that the rotenone-induced model presents non-motor and motor defects with extensive studies related to muscle atrophy.

Ferulic acid mitigated rotenone toxicity -Evoked Parkinson in rat model by featuring apoptosis, oxidative stress, and neuroinflammation signaling

Over time, Parkinson disease (PD) develops as a neurological illness. The goal of this study was to see whether ferulic acid has any neuroprotective benefits on the cerebellum of rats that have Parkinson's disease brought on by rotenone poisoning. A total of twenty-four male albino rats, in good condition, weighed between 200 and 250 g and nine to ten weeks old, were employed in the investigation. The control group received 1 ml of sunflower oil intraperitoneally (i.p.) each day. Rats' motor performance was considerably worse when given rotenone than it was in the control group. Rats given Ferulic Acid (FA) showed a substantial drop in the amount of glutathione (GSH) in the cerebellum. Moreover, the injection of FA resulted in a significant reduction in the optical density (OD) of the immune-positive reaction for α-synuclein, and the area percentage of BCL-2 and NF-kB immunological positive response. FA therapy, surprisingly, enhanced the OD of TH immunopositive response and apoptotic regulators (BCL2) in the cerebellum. Furthermore, FA boosted BCL2 expression, confirming the antiapoptotic effects of FA. Based on these results, FA is probably a good candidate to treat neurodegenerative diseases brought on by long-term exposure to rotenone.

Fucoidan ameliorates rotenone-induced Parkinsonism in mice by regulating the microbiota-gut-brain axis

Microbiota-gut-brain axis, the bidirectional relationship between the gut microbiota and the brain, has been increasingly appreciated in the pathogenesis of Parkinson's disease (PD). Fucoidan, a sulphate-rich polysaccharide, has been shown to be neuroprotective by reducing oxidative stress in PD models. However, the role of microbiota-gut-brain axis in the neuroprotective activity of fucoidan has not been revealed. In this study, the therapeutic effects of fucoidan and involvement of microbiota-gut-brain axis in rotenone (ROT)-induced PD were investigated. The results showed that fucoidan gavage attenuated neuroinflammation, dopamine neuronal damage and motor dysfunction in ROT-induced PD mice. In addition, fucoidan treatment ameliorated gut dysfunction, intestinal inflammation and disruption of the intestinal barrier in PD mice. Fucoidan also affected the composition of gut microbiota in PD mice, indicated particularly by decreased abundance of Akkermansia muciniphila and Lactobacillus johnsonii and increased abundance of Lactobacillus murinus. Mechanistic studies showed that fecal microbiota transplantation (FMT) from the fucoidan-treated mice and probiotic Lactobacillus murinus supplement are as potent as fucoidan treatment in attenuating peripheral and central inflammation and ameliorating dopamine neuronal damage, which might be attributed to the downregulation of LPS/TLR4/NF-κB signaling pathway. Our study suggests that fucoidan might be potential candidates for the treatment of PD.

Levodopa Impairs Lysosomal Function in Sensory Neurons In Vitro

Parkinson's disease (PD) is the second-most common neurodegenerative disease worldwide. Patients are diagnosed based upon movement disorders, including bradykinesia, tremor and stiffness of movement. However, non-motor signs, including constipation, rapid eye movement sleep behavior disorder, smell deficits and pain are well recognized. Peripheral neuropathy is also increasingly recognized, as the vast majority of patients show reduced intraepidermal nerve fibers, and sensory nerve conduction and sensory function is also impaired. Many case studies in the literature show that high-dose levodopa may induce or exacerbate neuropathy in PD, which is thought to involve levodopa's metabolism to homocysteine. Here, we treated primary cultures of dorsal root ganglia and a sensory neuronal cell line with levodopa to examine effects on cell morphology, mitochondrial content and physiology, and lysosomal function. High-dose levodopa reduced mitochondrial membrane potential. At concentrations observed in the patient, levodopa enhanced immunoreactivity to beta III tubulin. Critically, levodopa reduced lysosomal content and also reduced the proportion of lysosomes that were acidic, thereby impairing their function, whereas homocysteine tended to increase lysosome content. Levodopa is a critically important drug for the treatment of PD. However, our data suggest that at concentrations observed in the patient, it has deleterious effects on sensory neurons that are not related to homocysteine.

Pharmacological activities and therapeutic potential of Hyperoside in the treatment of Alzheimer's and Parkinson's diseases: A systemic review

Alzheimer's disease (AD) and Parkinson's disease (PD) are neurodegenerative disorders that significantly impact well-being. Hyperoside (HYP), a flavonoid found in various plant species, particularly within the genus Hypericin, exhibits diverse pharmacological properties. However, the precise mechanisms underlying the anti-AD and anti-PD effects of HYP remain unclear. This systematic review consolidated existing preclinical research on HYP by conducting a comprehensive literature survey and analysis. The objective was to corroborate the therapeutic efficacy of HYP in AD and PD models and to synthesize its potential therapeutic mechanisms. Searches were conducted in the PubMed, CNKI, and Web of Science databases. Reliability assessment of the 17 included studies confirmed the credibility of the mechanisms of action of HYP against AD and PD. We systematically assessed the neuroprotective potential of HYP in in vivo and in vitro models of AD and PD. Our findings indicated that HYP can mitigate, intervene in, and treat AD and PD animal models and associated cells through various mechanisms, including anti-oxidative, anti-inflammatory, anti-apoptotic, anti-Aβ aggregation, and cholinesterase inhibitory activities. Therefore, HYP potentially exerts anti-AD and anti-PD effects through diverse mechanisms, making it a promising candidate for therapeutic intervention in both AD and PD.

The potential of natural products to inhibit abnormal aggregation of α-Synuclein in the treatment of Parkinson's disease

Parkinson's disease (PD), as a refractory neurological disorder with complex etiology, currently lacks effective therapeutic agents. Natural products (NPs), derived from plants, animals, or microbes, have shown promising effects in PD models through their antioxidative and anti-inflammatory properties, as well as the enhancement of mitochondrial homeostasis and autophagy. The misfolding and deposition of α-Synuclein (α-Syn), due to abnormal overproduction and impaired clearance, being central to the death of dopamine (DA) neurons. Thus, inhibiting α-Syn misfolding and aggregation has become a critical focus in PD discovery. This review highlights NPs that can reduce α-Syn aggregation by preventing its overproduction and misfolding, emphasizing their potential as novel drugs or adjunctive therapies for PD treatment, thereby providing further insights for clinical translation.

The Interplay of Mitochondrial Bioenergetics and Dopamine Agonists as an Effective Disease-Modifying Therapy for Parkinson's Disease

Parkinson's disease (PD) is a progressive neurological ailment with a slower rate of advancement that is more common in older adults. The biggest risk factor for PD is getting older, and those over 60 have an exponentially higher incidence of this condition. The failure of the mitochondrial electron chain, changes in the dynamics of the mitochondria, and abnormalities in calcium and ion homeostasis are all symptoms of Parkinson's disease (PD). Increased mitochondrial reactive oxygen species (mROS) and an energy deficit are linked to these alterations. Levodopa (L-DOPA) is a medication that is typically used to treat most PD patients, but because of its negative effects, additional medications have been created utilizing L-DOPA as the parent molecule. Ergot and non-ergot derivatives make up most PD medications. PD is successfully managed with the use of dopamine agonists (DA). To get around the motor issues produced by L-DOPA, these dopamine derivatives can directly excite DA receptors in the postsynaptic membrane. In the past 10 years, two non-ergoline DA with strong binding properties for the dopamine D2 receptor (D2R) and a preference for the dopamine D3 receptor (D3R) subtype, ropinirole, and pramipexole (PPx) have been developed for the treatment of PD. This review covers the most recent research on the efficacy and safety of non-ergot drugs like ropinirole and PPx as supplementary therapy to DOPA for the treatment of PD.

Identification of Potential Therapeutics for Infantile Hemangioma via in silico Investigation and in vitro Validation

Introduction

Infantile Hemangioma (IH) is a prevalent benign vascular tumor affecting approximately 5-10% of infants. Its underlying pathogenesis remains enigmatic, and current therapeutic approaches show limited effectiveness. Our study aimed to discover potential IH-associated therapeutics through a transcriptomic, computational drug repurposing methodology.

Methods

Utilizing the IH-specific dataset GSE127487 from the Gene Expression Omnibus, we identified differentially expressed genes (DEGs) and conducted weighted gene coexpression network analysis (WGCNA). Subsequently, a protein-protein interaction (PPI) network was constructed to obtain the top 100 hub genes. Drug candidates were sourced from the Connectivity Map (CMap) and Comparative Toxicogenomics Database (CTD).

Results

Our analysis revealed 1203 DEGs and a significant module of 1780 mRNAs strongly correlated with IH. These genes were primarily enriched in the PI3K/AKT/MTOR, RAS/MAPK, and CGMP/PKG signaling pathway. After creating a PPI network of overlapping genes, we filtered out the top 100 hub genes. Ultimately, 44 non-toxic drugs were identified through the CMap and CTD databases. Twelve molecular-targeting agents (belinostat, chir 99021, dasatinib, entinostat, panobinostat, sirolimus, sorafenib, sunitinib, thalidomide, U 0126, vorinostat, and wortmannin) may be potential candidates for IH therapy. Moreover, in vitro experiments demonstrated that entinostat, sorafenib, dasatinib, and sirolimus restricted the proliferation and migration and initiated apoptosis in HemEC cells, thereby underscoring their potential therapeutic value.

Conclusion

Our investigation revealed that the pathogenic mechanism underlying IH might be closely associated with the PI3K/AKT/MTOR, RAS/MAPK, and CGMP/PKG signaling pathways. Furthermore, we identified twelve molecular-targeting agents among the predicted drugs that show promise as therapeutic candidates for IH.

Repurposing ezetimibe as a neuroprotective agent in a rotenone-induced Parkinson's disease model in rats: Role of AMPK/SIRT-1/PGC-1α signaling and autophagy

As a severe neurological disorder, Parkinson's disease (PD) is distinguished by dopaminergic neuronal degeneration in the substantia nigra (SN), culminating in motor impairments. Several studies have shown that activation of the AMPK/SIRT1/PGC1α pathway contributes to an increase in mitochondrial biogenesis and is a promising candidate for the management of PD. Furthermore, turning on the AMPK/SIRT1/PGC1α pathway causes autophagy activation, which is fundamental for maintaining neuronal homeostasis. Interestingly, ezetimibe is an antihyperlipidemic agent that was recently reported to possess pleiotropic properties in neurology by triggering the phosphorylation and activation of AMPK. Thus, our study aimed to investigate the neuroprotective potential of ezetimibe in rats with rotenone-induced PD by activating AMPK. Adult male Wistar rats received rotenone (1.5 mg/kg, s.c.) every other day for 21 days to induce experimental PD. Rats were treated with ezetimibe (5 mg/kg/day, i.p.) 1 h before rotenone. Ezetimibe ameliorated the motor impairments in open field, rotarod and grip strength tests, restored striatal dopamine and tyrosine hydroxylase in the SN, up-regulated p-AMPK, SIRT1, and PGC1α striatal expression, upsurged the expression of ULK1, beclin1, and LC3II/I, reduced Bax/Bcl2 ratio, and alleviated rotenone-induced histopathological changes in striatum and SN. Our findings also verified the contribution of AMPK activation to the neuroprotective effect of ezetimibe by using the AMPK inhibitor dorsomorphin. Together, this work revealed that ezetimibe exerts a neuroprotective impact in rotenone-induced PD by activating AMPK/SIRT-1/PGC-1α signaling, enhancing autophagy, and attenuating apoptosis. Thus, ezetimibe's activation of AMPK could hold significant therapeutic promise for PD management.

AR71, Histamine H3 Receptor Ligand-In Vitro and In Vivo Evaluation (Anti-Inflammatory Activity, Metabolic Stability, Toxicity, and Analgesic Action)

The future of therapy for neurodegenerative diseases (NDs) relies on new strategies targeting multiple pharmacological pathways. Our research led to obtaining the compound AR71 [(E)-3-(3,4,5-trimethoxyphenyl)-1-(4-(3-(piperidin-1-yl)propoxy)phenyl)prop-2-en-1-one], which has high affinity for human H3R (Ki = 24 nM) and selectivity towards histamine H1 and H4 receptors (Ki > 2500 nM), and showed anti-inflammatory activity in a model of lipopolysaccharide-induced inflammation in BV-2 cells. The presented tests confirmed its antagonist/inverse agonist activity profile and good metabolic stability while docking studies showed the binding mode to histamine H1, H3, and H4 receptors. In in vitro tests, cytotoxicity was evaluated at three cell lines (neuroblastoma, astrocytes, and human peripheral blood mononuclear cells), and a neuroprotective effect was observed in rotenone-induced toxicity. In vivo experiments in a mouse neuropathic pain model demonstrated the highest analgesic effects of AR71 at the dose of 20 mg/kg body weight. Additionally, AR71 showed antiproliferative activity in higher concentrations. These findings suggest the need for further evaluation of AR71's therapeutic potential in treating ND and CNS cancer using animal experimental models.

Syagrus coronata fixed oil prevents rotenone-induced movement disorders and oxidative stress in Drosophila melanogaster

One prominent aspect of Parkinson's disease (PD) is the presence of elevated levels of free radicals, including reactive oxygen species (ROS). Syagrus coronata (S. coronata), a palm tree, exhibits antioxidant activity attributed to its phytochemical composition, containing fatty acids, polyphenols, and flavonoids. The aim of this investigation was to examine the potential neuroprotective effects of S. coronata fixed oil against rotenone-induced toxicity using Drosophila melanogaster. Young Drosophila specimens (3-4 d old) were exposed to a diet supplemented with rotenone (50 µM) for 7 d with and without the inclusion of S. coronata fixed oil (0.2 mg/g diet). Data demonstrated that rotenone exposure resulted in significant locomotor impairment and increased mortality rates in flies. Further, rotenone administration reduced total thiol levels but elevated lipid peroxidation, iron (Fe) levels, and nitric oxide (NO) levels while decreasing the reduced capacity of mitochondria. Concomitant administration of S. coronata exhibited a protective effect against rotenone, as evidenced by a return to control levels of Fe, NO, and total thiols, lowered lipid peroxidation levels, reversed locomotor impairment, and enhanced % cell viability. Molecular docking of the oil lipidic components with antioxidant enzymes showed strong binding affinity to superoxide dismutase (SOD) and glutathione peroxidase (GPX1) enzymes. Overall, treatment with S. coronata fixed oil was found to prevent rotenone-induced movement disorders and oxidative stress in Drosophila melanogaster.

Toxic interactions between dopamine, α-synuclein, monoamine oxidase, and genes in mitochondria of Parkinson's disease

Parkinson's disease is characterized by its distinct pathological features; loss of dopamine neurons in the substantia nigra pars compacta and accumulation of Lewy bodies and Lewy neurites containing modified α-synuclein. Beneficial effects of L-DOPA and dopamine replacement therapy indicate dopamine deficit as one of the main pathogenic factors. Dopamine and its oxidation products are proposed to induce selective vulnerability in dopamine neurons. However, Parkinson's disease is now considered as a generalized disease with dysfunction of several neurotransmitter systems caused by multiple genetic and environmental factors. The pathogenic factors include oxidative stress, mitochondrial dysfunction, α-synuclein accumulation, programmed cell death, impaired proteolytic systems, neuroinflammation, and decline of neurotrophic factors. This paper presents interactions among dopamine, α-synuclein, monoamine oxidase, its inhibitors, and related genes in mitochondria. α-Synuclein inhibits dopamine synthesis and function. Vice versa, dopamine oxidation by monoamine oxidase produces toxic aldehydes, reactive oxygen species, and quinones, which modify α-synuclein, and promote its fibril production and accumulation in mitochondria. Excessive dopamine in experimental models modifies proteins in the mitochondrial electron transport chain and inhibits the function. α-Synuclein and familiar Parkinson's disease-related gene products modify the expression and activity of monoamine oxidase. Type A monoamine oxidase is associated with neuroprotection by an unspecific dose of inhibitors of type B monoamine oxidase, rasagiline and selegiline. Rasagiline and selegiline prevent α-synuclein fibrillization, modulate this toxic collaboration, and exert neuroprotection in experimental studies. Complex interactions between these pathogenic factors play a decisive role in neurodegeneration in PD and should be further defined to develop new therapies for Parkinson's disease.

Investigating the role of rotenone on human blood platelets: Molecular insights into abnormal platelet functions in Parkinson's disease

Parkinson's disease (PD) is a predominant neuromotor disorder characterized by the selective death of dopaminergic neurons in the midbrain. The majority of PD cases are sporadic or idiopathic, with environmental toxins and pollutants potentially contributing to its development or exacerbation. However, clinical PD patients are often associated with a reduced stroke frequency, where circulating blood platelets are indispensable. Although platelet structural impairment is evident in PD, the platelet functional alterations and their underlying molecular mechanisms are still obscure. Therefore, we investigated rotenone (ROT), an environmental neurotoxin that selectively destroys dopaminergic neurons mimicking PD, on human blood platelets to explore its impact on platelet functions, thus replicating PD conditions in vitro. Our study deciphered that ROT decreased thrombin-induced platelet functions, including adhesion, activation, secretion, and aggregation in human blood platelets. As ROT is primarily responsible for generating intracellular reactive oxygen species (ROS), and ROS is a key player regulating the platelet functional parameters, we went on to check the effect of ROT on platelet ROS production. In our investigation, it became evident that ROT treatment resulted in the stimulation of ROS production in human blood platelets. Additionally, we discovered that ROT induced ROS production by augmenting Ca2+ mobilization from inositol 1,4,5-trisphosphate receptor. Apart from this, the treatment of ROT triggers protein kinase C associated NADPH oxidase-mediated ROS production in platelets. In summary, this research, for the first time, highlights ROT-induced abnormal platelet functions and may provide a mechanistic insight into the altered platelet activities observed in PD patients.

No Evidence of Sensory Neuropathy in a Traditional Mouse Model of Idiopathic Parkinson's Disease

Parkinson's disease (PD) is the second-most common neurodegenerative disorder worldwide and is diagnosed based on motor impairments. Non-motor symptoms are also well-recognised in this disorder, and peripheral neuropathy is a frequent but poorly appreciated non-motor sign. Studying how central and peripheral sensory systems are affected can contribute to the development of targeted therapies and deepen our understanding of the pathophysiology of PD. Although the cause of sporadic PD is unknown, chronic exposure to the pesticide rotenone in humans increases the risk of developing the disease. Here, we aimed to investigate whether peripheral neuropathy is present in a traditional model of PD. Mice receiving intrastriatal rotenone showed greatly reduced dopamine terminals in the striatum and a reduction in tyrosine hydroxylase-positive neurons in the Substantia nigra pars compacta and developed progressive motor impairments in hindlimb stepping and rotarod but no change in spontaneous activity. Interestingly, repeated testing using gold-standard protocols showed no change in gut motility, a well-known non-motor symptom of PD. Importantly, we did not observe any change in heat, cold, or touch sensitivity, again based upon repeated testing with well-validated protocols that were statistically well powered. Therefore, this traditional model fails to replicate PD, and our data again reiterate the importance of the periphery to the disorder.

Rotenone-induced PINK1/Parkin-mediated mitophagy: establishing a silkworm model for Parkinson's disease potential

Parkinson's disease (PD), ranking as the second most prevalent neurodegenerative disorder globally, presents a pressing need for innovative animal models to deepen our understanding of its pathophysiology and explore potential therapeutic interventions. The development of such animal models plays a pivotal role in unraveling the complexities of PD and investigating promising treatment avenues. In this study, we employed transcriptome sequencing on BmN cells treated with 1 μg/ml rotenone, aiming to elucidate the underlying toxicological mechanisms. The investigation brought to light a significant reduction in mitochondrial membrane potential induced by rotenone, subsequently triggering mitophagy. Notably, the PTEN induced putative kinase 1 (PINK1)/Parkin pathway emerged as a key player in the cascade leading to rotenone-induced mitophagy. Furthermore, our exploration extended to silkworms exposed to 50 μg/ml rotenone, revealing distinctive motor dysfunction as well as inhibition of Tyrosine hydroxylase (TH) gene expression. These observed effects not only contribute valuable insights into the impact and intricate mechanisms of rotenone exposure on mitophagy but also provide robust scientific evidence supporting the utilization of rotenone in establishing a PD model in the silkworm. This comprehensive investigation not only enriches our understanding of the toxicological pathways triggered by rotenone but also highlights the potential of silkworms as a valuable model organism for PD research.

Gastrointestinal dysmotility in rodent models of Parkinson's disease

Multiple studies describe prodromal, nonmotor dysfunctions that affect the quality of life of patients who subsequently develop Parkinson's disease (PD). These prodromal dysfunctions comprise a wide array of autonomic issues, including severe gastrointestinal (GI) motility disorders such as dysphagia, delayed gastric emptying, and chronic constipation. Indeed, strong evidence from studies in humans and animal models suggests that the GI tract and its neural, mainly vagal, connection to the central nervous system (CNS) could have a major role in the etiology of PD. In fact, misfolded α-synuclein aggregates that form Lewy bodies and neurites, i.e., the histological hallmarks of PD, are detected in the enteric nervous system (ENS) before clinical diagnosis of PD. The aim of the present review is to provide novel insights into the pathogenesis of GI dysmotility in PD, focusing our attention on functional, neurochemical, and molecular alterations in animal models.

Cajanus cajan (L) Millsp seeds extract prevents rotenone-induced motor- and non-motor features of Parkinson disease in mice: Insight into mechanisms of neuroprotection

ETHNOPHARMACOLOGICAL RELEVANCE

Cajanus cajan (L) Millsp (Fabaceae) seed decoction is used by traditional healers in Nigeria as nerve tonic, hence, could be beneficial in the treatment of Parkinson's disease (PD), a progressive and debilitating neurodegenerative disease that imposes great burden on the healthcare system globally.

AIM OF THE STUDY

This study aimed at investigating the neuroprotective effect of ethanol seed extract of Cajanus cajan (CC) in the treatment of rotenone-induced motor symptoms and non-motor symptoms associated with PD.

MATERIALS AND METHODS

To assess the protective action of CC on rotenone-induced motor- and non-motor symptoms of PD, mice were first pretreated with CC (50, 100 or 200 mg/kg, p.o.) an hour before oral administration of rotenone (1 mg/kg, p.o, 0.5% in carboxyl-methylcellulose) for 28 consecutive days and weekly behavioural tests including motor assessment (open field test (OFT), rotarod, pole and cylinder tests) and non-motor assessment (novel object recognition (NOR), Y-maze test (YM), forced swim and tail suspension, gastric emptying and intestinal fluid accumulation tests) were carried out. The animals were euthanized on day 28 followed by the collection of brain for assessment of oxidative stress, inflammatory markers and immunohistochemical analysis of the striatum (STR) and substantia nigra (SN). Phytochemicals earlier isolated from CC were docked with protein targets linked with PD pathology such as; catechol-O-methyltransferase (COMT), tyrosine hydroxylase (TH) and Leucine rich receptor kinase (LRRK).

RESULTS

this study showed that CC significantly reduced rotenone-induced spontaneous motor impairment in OFT, pole, cylinder and rotarod tests in mice as well as significant improvement in non-motor features (significant reversal of rotenone-induced deficits discrimination index and spontaneous alternation behaviour in NORT and YM test, respectively, reduction in immobility time in forced swim/tail suspension test, gastrointestinal disturbance in intestinal transit time in mice. Moreso, rotenone-induced neurodegeneration, oxidative stress and neuroinflammation were significantly attenuated by CC administration. In addition, docking analysis showed significant binding affinity of CC phytochemicals with COMT, TH and LRRK2 receptors.

CONCLUSION

Cajanus cajan seeds extract prevented both motor and non-motor features of Parkinson disease in mice through its antioxidant and anti-inflammatory effects. Hence, could be a potential phytotherapeutic adjunct in the management of Parkinson disease.

Electroacupuncture at ST25 corrected gut microbial dysbiosis and SNpc lipid peroxidation in Parkinson's disease rats

Introduction

Parkinson's disease (PD) remains one kind of a complex, progressive neurodegenerative disease. Levodopa and dopamine agonists as widely utilized PD therapeutics have not shown significant positive long-term outcomes. Emerging evidences indicate that electroacupuncture (EA) have potential effects on the therapy of nervous system disorders, particularly PD, but its specific underlying mechanism(s) remains poorly understood, leading to the great challenge of clinical application and management. Previous study has shown that acupuncture ameliorates PD motor symptoms and dopaminergic neuron damage by modulating intestinal dysbiosis, but its intermediate pathway has not been sufficiently investigated.

Methods

A rat model of PD was induced using rotenone. The therapeutic effect of EA on PD was assessed using the pole and rotarod tests and immunohistostaining for tyrosine hydroxylase (TH) in the substantia nigra (SN) of brain. The role of gut microbiota was explored using 16S rRNA gene sequencing and metabonomic analysis. PICRUSt2 analysis, lipidomic analysis, LPS and inflammatory factor assays were used for subsequent exploration and validation. Correlation analysis was used to identify the key bacteria that EA regulates lipid metabolism to improve PD.

Results

The present study firstly reappeared the effects of EA on protecting motor function and dopaminergic neurons and modulation of gut microbial dysbiosis in rotenone-induced PD rat model. EA improved motor dysfunction (via the pole and rotarod tests) and protected TH+ neurons in PD rats. EA increased the abundance of beneficial bacteria such as Lactobacillus, Dubosiella and Bifidobacterium and decreased the abundance of Escherichia-Shigella and Morganella belonging to Pseudomonadota, suggesting that the modulation of gut microbiota by EA improving the symptoms of PD motility via alleviating LPS-induced inflammatory response and oxidative stress, which was also validated by various aspects such as microbial gene functional analysis, fecal metabolomics analysis, LPS and inflammatory factor assays and SNpc lipidomics analysis. Moreover, correlation analyses also verified strong correlations of Escherichia-Shigella and Morganella with motor symptoms and SNpc lipid peroxidation, explicating targets and intermediate pathways through which EA improve PD exercise symptom.

Conclusion

Our results indicate that the improvement of motor function in PD model by EA may be mediated in part by restoring the gut microbiota, which intermediate processes involve circulating endotoxins and inflammatory mediators, SNpc oxidative stress and lipid peroxidation. The gut-microbiome - brain axis may be a potential mechanism of EA treatment for the PD.

The potential role of glucose metabolism, lipid metabolism, and amino acid metabolism in the treatment of Parkinson's disease

PURPOSE OF REVIEW

Parkinson's disease (PD) is a common neurodegenerative disease, which can cause progressive deterioration of motor function causing muscle stiffness, tremor, and bradykinesia. In this review, we hope to describe approaches that can improve the life of PD patients through modifications of energy metabolism.

RECENT FINDINGS

The main pathological features of PD are the progressive loss of nigrostriatal dopaminergic neurons and the production of Lewy bodies. Abnormal aggregation of α-synuclein (α-Syn) leading to the formation of Lewy bodies is closely associated with neuronal dysfunction and degeneration. The main causes of PD are said to be mitochondrial damage, oxidative stress, inflammation, and abnormal protein aggregation. Presence of abnormal energy metabolism is another cause of PD. Many studies have found significant differences between neurodegenerative diseases and metabolic decompensation, which has become a biological hallmark of neurodegenerative diseases.

SUMMARY

In this review, we highlight the relationship between abnormal energy metabolism (Glucose metabolism, lipid metabolism, and amino acid metabolism) and PD. Improvement of key molecules in glucose metabolism, fat metabolism, and amino acid metabolism (e.g., glucose-6-phosphate dehydrogenase, triglycerides, and levodopa) might be potentially beneficial in PD. Some of these metabolic indicators may serve well during the diagnosis of PD. In addition, modulation of these metabolic pathways may be a potential target for the treatment and prevention of PD.

Rotenone impairs brain glial energetics and locomotor behavior in bumblebees

Bumblebees are essential pollinators of both wildflowers and crops and face multiple anthropogenic stressors, particularly the utilization of pesticides. Rotenone is an extensively applied neurotoxic pesticide that possesses insecticidal activities against a wide range of pests. However, whether environmentally realistic exposure levels of rotenone can damage neurons in bumblebee brains is still uncertain. Using single-cell RNA-seq, we revealed that rotenone induced cell-specific responses in bumblebee brains, emphasizing the disruption of energy metabolism and mitochondrial dysfunction in glial cells. Correspondingly, the gene regulatory network associated with neurotransmission was also suppressed. Notably, rotenone could specially reduce the number of dopaminergic neurons, impairing bumblebee's ability to fly and crawl. We also found impaired intestinal motility in rotenone-treated bumblebees. Finally, we demonstrated that many differentially expressed genes in our snRNA-seq data overlapped with rotenone-induced Parkinson's disease risk genes, especially in glial cells. Although rotenone is widely used owing to its hypotoxicity, we found that environmentally realistic exposure levels of rotenone induced disturbed glial energetics and locomotor dysfunction in bumblebees, which may lead to an indirect decline in this essential pollinator.

Geniposide protects against neurotoxicity in mouse models of rotenone-induced Parkinson's disease involving the mTOR and Nrf2 pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Fructus Gardeniae, with the effects of discharging fire, eliminating vexation, reducing fever and causing diuresis, and cooling blood to remove apthogentic heat, could be used to treat Parkinson's disease (PD). Geniposide, as the main active ingredient of Fructus Gardeniae, has been shown to have neuroprotective effects in several rodent models. Rotenone, a commonly used neurotoxin, induced PD model progresses slowly, but simulates the pathological changes of PD's slow progression.

AIM OF THE STUDY

Herein, we mainly investigated the neuroprotective effects of geniposide on rotenone-induced mouse model of PD and the underlined mechanism.

MATERIALS AND METHODS

C57BL/6 mice were treated with rotenone (30 mg/kg, p. o.) daily for 60 days. Geniposide (25 and 50 mg/kg, p. o.) were administered at alterative day 30 min before rotenone. On day 60, the challenging beam, spontaneous activity, and adhesive removal tests were performed to evaluate the motor activity. Dopamine, DOPAC and HVA levels were detected by UPLC-MS/MS methods. Dopaminergic neurodegeneration was assessed using immunohistochemistry staining. ROS production, MDA level and GSH: GSSG ratio were measured to analyze oxidative stress. Cleavage of PARP and caspase-3 were detected to assess neuronal apoptosis. The expression of Nrf2 and mTOR signaling were detected using Western blot.

RESULTS

Geniposide improved motor dysfunction, restored neurotransmitters levels, and attenuated dopaminergic neurodegeneration induced by rotenone in mice. Geniposide suppressed rotenone-induced neuronal oxidative damage associated with Nrf2 signaling, and neuronal apoptosis involving mTOR pathway.

CONCLUSIONS

Geniposide may exert a neuroprotective effect in a mouse model of PD by rotenone, and this effect might be relevant to Nrf2 associated antioxidant signaling and mTOR involved anti-apoptosis pathway.

Sesamol: A Phenolic Compound of Health Benefits and Therapeutic Promise in Neurodegenerative Diseases

Sesamol, one of the key bioactive ingredients of sesame seeds (Sesamum indicum L.), is responsible for many of its possible nutritional benefits. Both the Chinese and Indian medical systems have recognized the therapeutic potential of sesame seeds. It has been shown to have significant therapeutic potential against oxidative stress, inflammatory diseases, metabolic syndrome, neurodegeneration, and mental disorders. Sesamol is a benign molecule that inhibits the expression of inflammatory indicators like numerous enzymes responsible for inducing inflammation, protein kinases, cytokines, and redox status. This review summarises the potential beneficial effects of sesamol against neurological diseases including Alzheimer's disease (AD), Parkinson's disease (PD), and Huntington's disease (HD). Recently, sesamol has been shown to reduce amyloid peptide accumulation and attenuate cognitive deficits in AD models. Sesamol has also been demonstrated to reduce the severity of PD and HD in animal models by decreasing oxidative stress and inflammatory pathways. The mechanism of sesamol's pharmacological activities against neurodegenerative diseases will also be discussed in this review.

Pathogenic Impact of Fatty Acid-Binding Proteins in Parkinson's Disease-Potential Biomarkers and Therapeutic Targets

Parkinson's disease is a neurodegenerative condition characterized by motor dysfunction resulting from the degeneration of dopamine-producing neurons in the midbrain. This dopamine deficiency gives rise to a spectrum of movement-related symptoms, including tremors, rigidity, and bradykinesia. While the precise etiology of Parkinson's disease remains elusive, genetic mutations, protein aggregation, inflammatory processes, and oxidative stress are believed to contribute to its development. In this context, fatty acid-binding proteins (FABPs) in the central nervous system, FABP3, FABP5, and FABP7, impact α-synuclein aggregation, neurotoxicity, and neuroinflammation. These FABPs accumulate in mitochondria during neurodegeneration, disrupting their membrane potential and homeostasis. In particular, FABP3, abundant in nigrostriatal dopaminergic neurons, is responsible for α-synuclein propagation into neurons and intracellular accumulation, affecting the loss of mesencephalic tyrosine hydroxylase protein, a rate-limiting enzyme of dopamine biosynthesis. This review summarizes the characteristics of FABP family proteins and delves into the pathogenic significance of FABPs in the pathogenesis of Parkinson's disease. Furthermore, it examines potential novel therapeutic targets and early diagnostic biomarkers for Parkinson's disease and related neurodegenerative disorders.

Tephrosin Suppresses the Chemoresistance of Paclitaxel-Resistant Ovarian Cancer via Inhibition of FGFR1 Signaling Pathway

Ovarian cancer is the leading cause of death among gynecologic cancers. Paclitaxel is used as a standard first-line therapeutic agent for ovarian cancer. However, chemotherapeutic resistance and high recurrence rates are major obstacles to treating ovarian cancer. We have found that tephrosin, a natural rotenoid isoflavonoid, can resensitize paclitaxel-resistant ovarian cancer cells to paclitaxel. Cell viability, immunoblotting, and a flow cytometric analysis showed that a combination treatment made up of paclitaxel and tephrosin induced apoptotic death. Tephrosin inhibited the phosphorylation of AKT, STAT3, ERK, and p38 MAPK, all of which simultaneously play important roles in survival signaling pathways. Notably, tephrosin downregulated the phosphorylation of FGFR1 and its specific adapter protein FRS2, but it had no effect on the phosphorylation of the EGFR. Immunoblotting and a fluo-3 acetoxymethyl assay showed that tephrosin did not affect the expression or function of P-glycoprotein. Additionally, treatment with N-acetylcysteine did not restore cell cytotoxicity caused by a treatment combination made up of paclitaxel and tephrosin, showing that tephrosin did not affect the reactive oxygen species scavenging pathway. Interestingly, tephrosin reduced the expression of the anti-apoptotic factor XIAP. This study demonstrates that tephrosin is a potent antitumor agent that can be used in the treatment of paclitaxel-resistant ovarian cancer via the inhibition of the FGFR1 signaling pathway.

Flavonoids in Combination with Stem Cells for the Treatment of Neurological Disorders

Neurological disorders are the leading cause of disability and the world's second leading cause of death. Despite the availability of significant knowledge to reduce the burden of some neurological disorders, various studies are exploring more effective treatment options. While the human body can repair and regenerate damaged tissue through stem cell recruitment, nerve regeneration in case of injury is minimal due to the restriction on the location of nerve stem cells. Recently, different types of stem cells extracted from various tissues have been used in combination with natural stimuli to treat neurologic disorders in neuronal tissue engineering. Flavonoids are polyphenolic compounds that can induce the differentiation of stem cells into neurons and stimulate stem cell proliferation, migration, and survival. They can also increase the secretion of nutritional factors from stem cells. In addition to the effects that flavonoids can have on stem cells, they can also have beneficial therapeutic effects on the nervous system alone. Therefore, the simultaneous use of these compounds and stem cells can multiply the therapeutic effect. In this review, we first introduce flavonoid compounds and provide background information on stem cells. We then compile available reports on the effects of flavonoids on stem cells for the treatment of neurological disorders.

Transformable nano-antibiotics for mechanotherapy and immune activation against drug-resistant Gram-negative bacteria

The dearth of antibiotic candidates against Gram-negative bacteria and the rise of antibiotic resistance create a global health concern. The challenge lies in the unique Gram-negative bacterial outer membrane that provides the impermeable barrier for antibiotics and sequesters antigen presentation. We designed a transformable nano-antibiotics (TNA) that can transform from nontoxic nanoparticles to bactericidal nanofibrils with reasonable rigidity (Young's modulus, 21.6 ± 5.9 MPa) after targeting β-barrel assembly machine A (BamA) and lipid polysaccharides (LPSs) of Gram-negative bacteria. After morphological transformation, the TNA can penetrate and damage the bacterial envelope, disrupt electron transport and multiple conserved biosynthetic and metabolic pathways, burst bacterial antigen release from the outer membrane, and subsequently activate the innate and adaptive immunity. TNA kills Gram-negative bacteria in vitro and in vivo with undetectable resistance through multiple bactericidal modes of action. TNA treatment-induced vaccination results in rapid and long-lasting immune responses, protecting against lethal reinfections.

Experimental models of gut-first Parkinson's disease: A systematic review

BACKGROUND

There is strong support from studies in humans and in animal models that Parkinson's disease (PD) may begin in the gut. This brings about a unique opportunity for researchers in the field of neurogastroenterology to contribute to advancing the field and making contributions that could lead to the ability to diagnose and treat PD in the premotor stages. Lack of familiarity with some of the aspects of the experimental approaches used in these studies may present a barrier for neurogastroenterology researchers to enter the field. Much remains to be understood about intestinal-specific components of gut-first PD pathogenesis and the field would benefit from contributions of enteric and central nervous system neuroscientists.

PURPOSE

To address these issues, we have conducted a systematic review of the two most frequently used experimental models of gut-first PD: transneuronal propagation of α-synuclein preformed fibrils and oral exposure to environmental toxins. We have reviewed the details of these studies and present methodological considerations for the use of these models. Our aim is that this review will serve as a framework and useful reference for neuroscientists, gastroenterologists, and neurologists interested in applying their expertise to advancing our understanding of gut-first PD.

EP1 receptor: Devil in emperors coat

EP1 receptor belongs to prostanoid receptors and is activated by prostaglandin E2. The receptor performs contrasting functions in central nervous system (CNS) and other tissues. Although the receptor is neurotoxic and proapoptotic in CNS, it has also been reported to act in an antiapoptotic manner by modulating cell survival, proliferation, invasion, and migration in different types of cancers. The receptor mediates its neurotoxic effects by increasing cytosolic Ca2+ levels, leading to the activation of its downstream target, protein kinase C, in different neurological disorders including Alzheimer's disease, Parkinson's disease, stroke, amyotrophic lateral sclerosis, and epilepsy. Antagonists ONO-8713, SC51089, and SC51322 against EP1 receptor ameliorate the neurotoxic effect by attenuating the neuroinflammation. The receptor also shows increased expression in different types of cancers and has been found to activate different signaling pathways, which lead to the development, progression, and metastasis of different cancers. The receptor stimulates the cell survival pathway by phosphorylating the AKT and PTEN (phosphatase and tensin homolog deleted on chromosome 10) signaling pathways. Although there are limited studies about this receptor and not a single clinical trial has been targeting the EP1 receptor for different neurological disorders or cancer, the receptor is appearing as a potential candidate for therapeutic targets. The aim of this article is to review the recent progress in understanding the pathogenic roles of EP1 receptors in different pathological conditions.

Mitochondrial Bioenergy in Neurodegenerative Disease: Huntington and Parkinson

Strong evidence suggests a correlation between degeneration and mitochondrial deficiency. Typical cases of degeneration can be observed in physiological phenomena (i.e., ageing) as well as in neurological neurodegenerative diseases and cancer. All these pathologies have the dyshomeostasis of mitochondrial bioenergy as a common denominator. Neurodegenerative diseases show bioenergetic imbalances in their pathogenesis or progression. Huntington's chorea and Parkinson's disease are both neurodegenerative diseases, but while Huntington's disease is genetic and progressive with early manifestation and severe penetrance, Parkinson's disease is a pathology with multifactorial aspects. Indeed, there are different types of Parkinson/Parkinsonism. Many forms are early-onset diseases linked to gene mutations, while others could be idiopathic, appear in young adults, or be post-injury senescence conditions. Although Huntington's is defined as a hyperkinetic disorder, Parkinson's is a hypokinetic disorder. However, they both share a lot of similarities, such as neuronal excitability, the loss of striatal function, psychiatric comorbidity, etc. In this review, we will describe the start and development of both diseases in relation to mitochondrial dysfunction. These dysfunctions act on energy metabolism and reduce the vitality of neurons in many different brain areas.

Developmental origins of Parkinson disease: Improving the rodent models

Numerous pesticides are inhibitors of the oxidative phosphorylation system. Oxidative phosphorylation dysfunction adversely affects neurogenesis and often accompanies Parkinson disease. Since brain development occurs mainly in the prenatal period, early exposure to pesticides could alter the development of the nervous system and increase the risk of Parkinson disease. Different rodent models have been used to confirm this hypothesis. However, more precise considerations of the selected strain, the xenobiotic, its mode of administration, and the timing of animal analysis, are necessary to resemble the model to the human clinical condition and obtain more reliable results.

Rotenone-Induced Model of Parkinson's Disease: Beyond Mitochondrial Complex I Inhibition

Parkinson's disease (PD) is usually diagnosed through motor symptoms that make the patient incapable of carrying out daily activities; however, numerous non-motor symptoms include olfactory disturbances, constipation, depression, excessive daytime sleepiness, and rapid eye movement at sleep; they begin years before motor symptoms. Therefore, several experimental models have been studied to reproduce several PD functional and neurochemical characteristics; however, no model mimics all the PD motor and non-motor symptoms to date, which becomes a limitation for PD study. It has become increasingly relevant to find ways to study the disease from its slowly progressive nature. The experimental models most frequently used to reproduce PD are based on administering toxic chemical compounds, which aim to imitate dopamine deficiency. The most used toxic compounds to model PD have been 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and 6-hydroxydopamine (6-OHDA), which inhibit the complex I of the electron transport chain but have some limitations. Another toxic compound that has drawn attention recently is rotenone, the classical inhibitor of mitochondrial complex I. Rotenone triggers the progressive death of dopaminergic neurons and α-synuclein inclusions formation in rats; also, rotenone induces microtubule destabilization. This review presents information about the experimental model of PD induced by rotenone, emphasizing its molecular characteristics beyond the inhibition of mitochondrial complex I.

Monoterpenoid Epoxidiol Ameliorates the Pathological Phenotypes of the Rotenone-Induced Parkinson’s Disease Model by Alleviating Mitochondrial Dysfunction

Parkinson’s disease is the second most common neurodegenerative disease. Unfortunately, there is still no definitive disease-modifying therapy. In our work, the antiparkinsonian potential of trans-epoxide (1S,2S,3R,4S,6R)-1-methyl-4-(prop-1-en-2-yl)-7-oxabicyclo [4.1.0]heptan-2,3-diol (E-diol) was analyzed in a rotenone-induced neurotoxicity model using in vitro, in vivo and ex vivo approaches. It was conducted as part of the study of the mitoprotective properties of the compound. E-diol has been shown to have cytoprotective properties in the SH-SY5Y cell line exposed to rotenone, which is associated with its ability to prevent the loss of mitochondrial membrane potential and restore the oxygen consumption rate after inhibition of the complex I function. Under the conditions of rotenone modeling of Parkinson’s disease in vivo, treatment with E-diol led to the leveling of both motor and non-motor disorders. The post-mortem analysis of brain samples from these animals demonstrated the ability of E-diol to prevent the loss of dopaminergic neurons. Moreover, that substance restored functioning of the mitochondrial respiratory chain complexes and significantly reduced the production of reactive oxygen species, preventing oxidative damage. Thus, E-diol can be considered as a new potential agent for the treatment of Parkinson’s disease.

Neuroprotective Effect of Propolis Polyphenol-Based Nanosheets in Cellular and Animal Models of Rotenone-Induced Parkinson's Disease

Considering the central role of oxidative stress in the onset and progress of Parkinson's diseases (PD), search for compounds with antioxidant properties has attracted a growing body of attention. Here, we compare the neuroprotective effect of bulk and nano forms of the polyphenolic fraction of propolis (PFP) against rotenone-induced cellular and animal models of PD. Mass spectrometric analysis of PFP confirmed the presence of multiple polyphenols including kaempferol, naringenin, coumaric acid, vanillic acid, and ferulic acid. In vitro cellular experiments indicate the improved efficiency of the nano form, compared to the bulk form, of PFP in attenuating rotenone-induced cytotoxicity characterized by a decrease in cell viability, release of lactate dehydrogenase, increased ROS generation, depolarization of the mitochondrial membrane, decreased antioxidant enzyme activity, and apoptosis induction. In vivo experiments revealed that while no significant neuroprotection was observed relating to the bulk form, PFP nanosheets were very effective in protecting animals, as evidenced by the improved behavioral and neurochemical parameters, including decreased lipid peroxidation, increased GSH content, and antioxidant enzyme activity enhancement. We suggest that improved neuroprotective effects of PFP nanosheets may be attributed to their increased water solubility and enrichment with oxygen-containing functional groups (such as OH and COOH), leading to increased antioxidant activity of these compounds.

Linagliptin counteracts rotenone's toxicity in non-diabetic rat model of Parkinson's disease: Insights into the neuroprotective roles of DJ-1, SIRT-1/Nrf-2 and implications of HIF1-α

While all current therapies' main focus is enhancing dopaminergic effects and remission of symptoms, delaying Parkinson's disease (PD) progression remains a challenging mission. Linagliptin, a Dipeptidyl Peptidase-4 (DPP-4) Inhibitor, exhibited neuroprotection in various neurodegenerative diseases. This study aims to evaluate the neuroprotective effects of Linagliptin in a rotenone-induced rat model of PD and investigate the possible underlying mechanisms of Linagliptin's actions. The effects of two doses of Linagliptin (5 and 10 mg/kg) on spontaneous locomotion, catalepsy, coordination and balance, and histology were assessed. Then, after Linagliptin showed promising results, it was further tested for its potential anti-inflammatory, antiapoptotic effects, and different pathways for oxidative stress. Linagliptin prevented rotenone-induced motor deficits and histological damage. Besides, it significantly inhibited the rotenone-induced increase in pro-inflammatory cytokines: Tumor Necrosis Factor-α (TNF-α) and Interleukin-6 (IL-6) and decrease in caspase 3 levels. These effects were associated with induction in the levels of Protein deglycase also known as DJ-1, Hypoxia-inducible factor 1-alpha (HIF-1α), potentiation in the Sirtuin 1 (SIRT-1)/Nuclear factor erythroid-2-related factor 2 (Nrf-2)/Heme oxygenase-1 (HO-1) pathway, and an increase in the antioxidant activity of catalase which provided neuroprotection to the neurons from rotenone-induced PD. Collectively, these results suggest that Linagliptin might be a suitable candidate for the management of PD.

Repaglinide Elicits a Neuroprotective Effect in Rotenone-Induced Parkinson's Disease in Rats: Emphasis on Targeting the DREAM-ER Stress BiP/ATF6/CHOP Trajectory and Activation of Mitophagy

Repaglinide, a meglitinide insulinotropic antidiabetic, was unraveled as a promising therapeutic agent for Huntington's disease by targeting the neuronal calcium sensor downstream regulatory element antagonist modulator (DREAM). However, its mechanistic profile in Parkinson's disease (PD) especially its impact on endoplasmic reticulum (ER) stress, mitophagy, and their interconnections is poorly elucidated. This study is the first to examine the neuroprotective potential of repaglinide in rotenone-induced PD in rats by exploring its effects on DREAM, BiP/ATF6/CHOP ER stress pathway, apoptosis, mitophagy/autophagy, oxidative stress, astrogliosis/microgliosis, and neuroinflammation. Male Wistar rats were randomly assigned to four groups: groups 1 and 2 received the vehicle or repaglinide (0.5 mg/kg/day p.o). Groups 3 and 4 received rotenone (1.5 mg/kg/48 h s.c) for 21 days; meanwhile, group 4 additionally received repaglinide (0.5 mg/kg/day p.o) for 15 days starting from day 11. Interestingly, repaglinide lessened striatal ER stress and apoptosis as evidenced by reduced BiP/ATF6/CHOP and caspase-3 levels; however, it augmented striatal DREAM mRNA expression. Repaglinide triggered the expression of the mitophagy marker PINK1 and the autophagy protein beclin1 and alleviated striatal oxidative stress through escalating catalase activity. In addition, repaglinide halted astrocyte/microglial activation and neuroinflammation in the striatum as expressed by reducing glial fibrillary acidic protein (GFAP) and ionized calcium-binding adaptor protein 1 (Iba1) immunostaining and decreasing interleukin (IL)-6 and IL-1β levels. Repaglinide restored striatum morphological alterations, intact neuron count, and neurobehavioral motor performance in rats examined by an open field, grip strength, and footprint gait analysis. Conclusively, repaglinide modulates the DREAM-ER stress BiP/ATF6/CHOP cascade, increases mitophagy/autophagy, inhibits apoptosis, and lessens oxidative stress, astrocyte/microglial activation, and neuroinflammation in PD.

«One Small Step for Mouse»: High CO2 Inhalation as a New Therapeutic Strategy for Parkinson's Disease

Parkinson's disease (PD) is a ubiquitous neurodegenerative disorder for which no effective treatment strategies are available. Existing pharmacotherapy is aimed only at correcting symptoms and slowing the progression of the disease, mainly by replenishing dopamine deficiency. It is assumed that mitochondrial dysfunction plays a key role in the pathogenesis of PD. It has been suggested that activation of specific degradation of damaged mitochondria (mitophagy) may prevent cell death. An almost exclusive way to initiate mitophagy is acidification of intracellular pH. We attempted to implement transient brain acidification using two experimental therapy strategies: forced moderate physical activity and high CO2 inhalation. The beneficial effects of CO2 supplementation on behavioral aspects were demonstrated in a rotenone-induced PD model. Mice treated with CO2 restored their exploratory behavior and total locomotor activity lost after rotenone administration. Additionally, this treatment enabled the removal of impaired coordination. We have illustrated this therapeutic strategy using histological studies of brain sections to confirm the survival of nigrostriatal areas. These findings suggest that high CO2 inhalation presumably initiates mitophagy via transient brain acidification, and can treat PD-like symptoms in a rodent rotenone model of PD.

Non-Reproducibility of Oral Rotenone as a Model for Parkinson's Disease in Mice

Oral rotenone has been proposed as a model for Parkinson’s disease (PD) in mice. To establish the model in our lab and study complex behavior we followed a published treatment regimen. C57BL/6 mice received 30 mg/kg body weight of rotenone once daily via oral administration for 4 and 8 weeks. Motor functions were assessed by RotaRod running. Immunofluorescence studies were used to analyze the morphology of dopaminergic neurons, the expression of alpha-Synuclein (α-Syn), and inflammatory gliosis or infiltration in the substantia nigra. Rotenone-treated mice did not gain body weight during treatment compared with about 4 g in vehicle-treated mice, which was however the only robust manifestation of drug treatment and suggested local gut damage. Rotenone-treated mice had no deficits in motor behavior, no loss or sign of degeneration of dopaminergic neurons, no α-Syn accumulation, and only mild microgliosis, the latter likely an indirect remote effect of rotenone-evoked gut dysbiosis. Searching for explanations for the model failure, we analyzed rotenone plasma concentrations via LC-MS/MS 2 h after administration of the last dose to assess bioavailability. Rotenone was not detectable in plasma at a lower limit of quantification of 2 ng/mL (5 nM), showing that oral rotenone had insufficient bioavailability to achieve sustained systemic drug levels in mice. Hence, oral rotenone caused local gastrointestinal toxicity evident as lack of weight gain but failed to evoke behavioral or biological correlates of PD within 8 weeks.

Assessing the Neurotoxicity of a Sub-Optimal Dose of Rotenone in Zebrafish (Danio rerio) and the Possible Neuroactive Potential of Valproic Acid, Combination of Levodopa and Carbidopa, and Lactic Acid Bacteria Strains

Parkinson’s disease (PD) is an enigmatic neurodegenerative disorder that is currently the subject of extensive research approaches aiming at deepening the understanding of its etiopathophysiology. Recent data suggest that distinct compounds used either as anticonvulsants or agents usually used as dopaminergic agonists or supplements consisting of live active lactic acid bacteria strains might alleviate and improve PD-related phenotypes. This is why we aimed to elucidate how the administration of rotenone (ROT) disrupts homeostasis and the possible neuroactive potential of valproic acid (VPA), antiparkinsonian agents (levodopa and carbidopa – LEV+CARB), and a mixture of six Lactobacillus and three Bifidobacterium species (PROBIO) might re-establish the optimal internal parameters. ROT causes significant changes in the central nervous system (CNS), notably reduced neurogenesis and angiogenesis, by triggering apoptosis, reflected by the increased expression of PARKIN and PINK1 gene(s), low brain dopamine (DA) levels, and as opposed to LRRK2 and SNCA compared with healthy zebrafish. VPA, LEV/CARB, and PROBIO sustain neurogenesis and angiogenesis, manifesting a neuroprotective role in diminishing the effect of ROT in zebrafish. Interestingly, none of the tested compounds influenced oxidative stress (OS), as reflected by the level of malondialdehyde (MDA) level and superoxide dismutase (SOD) enzymatic activity revealed in non-ROT-exposed zebrafish. Overall, the selected concentrations were enough to trigger particular behavioral patterns as reflected by our parameters of interest (swimming distance (mm), velocity (mm/s), and freezing episodes (s)), but sequential testing is mandatory to decipher whether they exert an inhibitory role following ROT exposure. In this way, we further offer data into how ROT may trigger a PD-related phenotype and the possible beneficial role of VPA, LEV+CARB, and PROBIO in re-establishing homeostasis in Danio rerio.

Targeting the inflammasome in Parkinson's disease

Parkinson's disease (PD) is one of the most common neurodegenerative diseases in which neuroinflammation plays pivotal roles. An important mechanism of neuroinflammation is the NLRP3 inflammasome activation that has been implicated in PD pathogenesis. In this perspective, we will discuss the relationship of some key PD-associated proteins including α-synuclein and Parkin and their contribution to inflammasome activation. We will also review promising inhibitors of NLRP3 inflammasome pathway that have potential as novel PD therapeutics. Finally, we will provide a summary of current and potential in vitro and in vivo models that are available for therapeutic discovery and development.