Evaluation of Potential Neuroprotective Effects of Vanillin Against MPP+/MPTP-Induced Dysregulation of Dopaminergic Regulatory Mechanisms in SH-SY5Y Cells and a Mouse Model of Parkinson's Disease

Brazilin-Rich Extract from Caesalpinia sappan L. Attenuated the Motor Deficits and Neurodegeneration in MPTP/p-Induced Parkinson's Disease Mice by Regulating Gut Microbiota and Inhibiting Inflammatory Responses

Parkinson's disease (PD) is a complicated neurological disease with an unclear pathogenesis. However, dysregulation of gut microbiota and inflammation response play crucial roles in the progression of PD. Caesalpinia sappan L., a traditional medicinal plant containing brazilin as its primary active compound, is known for its anti-inflammatory and neuroprotective properties. However, the impact of C. sappan L. extract (SE) on PD through the regulation of the microbiota-gut-brain axis remains unclear. This study investigated the effects and mechanisms of a 91.23% brazilin-enriched SE on MPTP/p-induced PD mice. Results showed that SE significantly ameliorated motor deficits and protected dopaminergic neurons in PD mice. Additionally, SE reduced oxidative stress and inflammation in the brain. SE also restored gut microbiota by increasing Firmicutes and decreasing Bacteroidetes, alongside enhancing the production of short-chain fatty acids (SCFAs) like butyric acid. Furthermore, SE mitigated intestinal barrier damage by enhancing the expression of ZO-1 and occludin, thereby decreasing lipopolysaccharide leakage and inflammatory factor release. Molecular simulations suggested that butyric acid may maintain intestinal integrity by stabilizing ZO-I and occludin conformations. In conclusion, SE exhibited a protective effect on motor deficits and neurodegeneration in PD by regulating gut microbiota and SCFAs, repairing the intestinal barrier, and mitigating inflammatory responses.

Phosphinothio(seleno)ation of alkynes/olefins and application on the late-stage functionalization of natural products

Non-metallic catalysis has been known as a remarkable development strategy for hydrofunctionalization of unsaturated hydrocarbons. Herein, we report a unique chemically active method of BF3·OEt2 promoted multi-component, highly regioselective, and chemoselective hydrothio(seleo)phosphonylation of unsaturated hydrocarbons, which exhibits high yield and good substrate universality. The reaction mechanism was further elucidated to be Markovnikov addition by controlling experiments, 31P and 19F NMR spectra tracking experiments, X-ray diffraction analysis, and DFT calculations. Furthermore, the gram-scale attempt and the application of the reaction on the derivatization of natural products have been successfully conducted, leading to the discovery of 3as with potential anti-Parkinson's disease (PD) activities at 1 μM. This streamlined and efficient methodology has established a new platform for non-metallic Lewis acids-promoted hydrofunctionalization of unsaturated hydrocarbons and its application on new drug research.

SHANK2-AS3: A potential biomarker for Parkinson's disease and its role in neuronal apoptosis via NF-κB signaling in SH-SY5Y cells

Parkinson's disease (PD) is a progressive neurodegenerative disorder primarily driven by the degeneration of dopaminergic neurons, manifesting as hallmark symptoms such as muscle rigidity, tremors, and motor dysfunction, all of which severely compromise patients' quality of life. Increasing evidence highlights the critical role of long non-coding RNAs (lncRNAs) in PD pathogenesis. However, the specific involvement of SHANK2-AS3 in PD remains unclear. By reanalyzing the dysregulated lncRNAs from the GSE22491 dataset, we identified a significant upregulation of SHANK2-AS3 in PD patients compared to healthy controls. This finding was further validated in a new cohort of PD patients, where SHANK2-AS3 expression was notably elevated in peripheral blood samples. Additionally, we observed a marked increase in SHANK2-AS3 expression in MPTP-treated SH-SY5Y cells, a commonly used in vitro PD model. Functional assays demonstrated that SHANK2-AS3 knockdown attenuated MPTP-induced apoptosis, reduced reactive oxygen species (ROS) accumulation, and improved mitochondrial function. In contrast, SHANK2-AS3 overexpression exacerbated neuronal apoptosis. RNA sequencing and Western blot analyses revealed that the NF-κB signaling pathway is involved in SHANK2-AS3-mediated neuronal apoptosis. In summary, our findings suggest that SHANK2-AS3 plays a critical role in PD pathogenesis and represents a potential therapeutic target for mitigating neuronal damage in PD.

Coumarin-chalcone derivatives as dual NLRP1 and NLRP3 inflammasome inhibitors targeting oxidative stress and inflammation in neurotoxin-induced HMC3 and BE(2)-M17 cell models of Parkinson's disease

Background

In Parkinson's disease (PD) brains, microglia are activated to release inflammatory factors to induce the production of reactive oxygen species (ROS) in neuron, and vice versa. Moreover, neuroinflammation and its synergistic interaction with oxidative stress contribute to the pathogenesis of PD.

Methods

In this study, we investigated whether in-house synthetic coumarin-chalcone derivatives protect human microglia HMC3 and neuroblastoma BE(2)-M17 cells against 1-methyl-4-phenyl pyridinium (MPP+)-induced neuroinflammation and associated neuronal damage.

Results

Treatment with MPP+ decreased cell viability as well as increased the release of inflammatory mediators including cytokines and nitric oxide in culture medium, and enhanced expression of microglial activation markers CD68 and MHCII in HMC3 cells. The protein levels of NLRP3, CASP1, iNOS, IL-1β, IL-6, and TNF-α were also increased in MPP+-stimulated HMC3 cells. Among the four tested compounds, LM-016, LM-021, and LM-036 at 10 μM counteracted the inflammatory action of MPP+ in HMC3 cells. In addition, LM-021 and LM-036 increased cell viability, reduced lactate dehydrogenase release, ameliorated cellular ROS production, decreased caspase-1, caspase-3 and caspase-6 activities, and promoted neurite outgrowth in MPP+-treated BE(2)-M17 cells. These protective effects were mediated by down-regulating inflammatory NLRP1, IL-1β, IL-6, and TNF-α, as well as up-regulating antioxidative NRF2, NQO1, GCLC, and PGC-1α, and neuroprotective CREB, BDNF, and BCL2.

Conclusion

The study results strengthen the involvement of neuroinflammation and oxidative stress in PD pathogenic mechanisms, and indicate the potential use of LM-021 and LM-036 as dual inflammasome inhibitors in treating both NLRP1- and NLRP3-associated PD.

Medicinal herbal remedies in neurodegenerative diseases: an update on antioxidant potential

It has been widely documented that medicinal herbal remedies are effective, have fewer side effects than conventional medicine, and have a synergistic effect on health collaborations in the fight against complicated diseases. Traditional treatments for neurological problems in ancient times sometimes involved the use of herbal remedies and conventional methods from East Asian countries including India, Japan, China, and Korea. We collected and reviewed studies on plant-derived neuroprotective drugs and tested them in neurotoxic models. Basic research, preclinical and clinical transgene research can benefit from in silico, in vitro, and in vivo investigations. Research, summaries of the extracts, fractions, and herbal ingredients were compiled from popular scientific databases, which were then examined according to origin and bioactivity. Given the complex and varied causes of neurodegeneration, it may be beneficial to focus on multiple mechanisms of action and a neuroprotection approach. This approach aims to prevent cell death and restore function to damaged neurons, offering promising strategies for preventing and treating neurodegenerative diseases. Neurodegenerative illnesses can potentially be treated with natural compounds that have been identified as neuroprotective agents. To gain deeper insights into the neuropharmacological mechanisms underlying the neuroprotective and therapeutic properties of naturally occurring antioxidant phytochemical compounds in diverse neurodegenerative diseases, this study aims to comprehensively review such compounds, focusing on their modulation of apoptotic markers such as caspase, Bax, Bcl-2, and proinflammatory markers. In addition, we delve into a range of efficacies of antioxidant phytochemical compounds as neuroprotective agents in animal models. They reduce the oxidative stress of the brain and have been shown to have anti-apoptotic effects. Many researches have demonstrated that plant extracts or bioactive compounds can fight neurodegenerative disorders. Herbal medications may offer neurodegenerative disease patients' new treatments. This may be a cheaper and more culturally appropriate alternative to standard drugs for millions of people with age-related NDDs.

MiR-29a efficiently suppresses the generation of reactive oxygen species and α-synuclein in a cellular model of Parkinson's disease by potentially targeting GSK-3β

MicroRNA-29a (miR-29a) has been suggested to serve a potential protective function against Parkinson's disease (PD); however, the exact molecular mechanisms remain elusive. This study explored the protective role of miR-29a in a cellular model of PD using SH-SY5Y cell lines through iTRAQ-based quantitative proteomic and biochemistry analysis. The findings showed that using a miR-29a mimic in SH-SY5Y cells treated with 1-methyl-4-phenylpyridinium (MPP+) significantly decreased cell death and increased mitochondrial membrane potential. It also reduced mitochondrial reactive oxygen species (ROS) and the production of α-synuclein. Subsequent heatmap analysis using iTRAQ-based quantitative proteomics revealed remarkably contrasting protein expression profiles for 882 genes when comparing the groups treated with miR-29a mimic plus MPP + against the control group treated solely with MPP+. The KEGG pathway analysis of these 882 genes indicated the substantial role of miR-29a in the PD pathway (P = 1.58x10-5) and highlighted its function in mitochondrial genes. Furthermore, treatment with a miR-29a mimic in SH-SY5Y cells reduced the levels of GSK-3β, phosphorylated GSK-3β, and cleaved caspase-7 following exposure to MPP+. The miR-29a mimic also upregulated the expressions of α-synuclein clearance proteins FYCO1 and Rab7 in this cellular PD model, thereby inhibiting the production of α-synuclein. Luciferase activity analysis confirmed the specific binding of miR-29a to the 3' untranslated region (3'UTR) of GSK-3β, leading to its repression. Our findings demonstrated miR-29a's neuroprotective role in mitochondrial function and highlighted its potential to inhibit ROS and α-synuclein production, offering possible therapeutic avenues for PD treatment.

Functional modification of recombinant brain-derived neurotrophic factor and its protective effect against neurotoxicity

Brain-derived neurotrophic factor (BDNF) is a neurotrophic protein that promotes neuronal survival, increases neurotransmitter synthesis, and has potential therapeutic effects in neurodegenerative and psychiatric diseases, but its drug development has been limited by the fact that recombinant proteins of BDNF are unstable and do not penetrate the blood-brain barrier (BBB). In this study, we fused a TAT membrane-penetrating peptide with BDNF to express a recombinant protein (TBDNF), which was then PEG-modified to P-TBDNF. Protein characterization showed that P-TBDNF significantly improved the stability of the recombinant protein and possessed the ability to penetrate the BBB, and in cellular experiments, P-TBDNF prevented MPTP-induced nerve cell oxidative stress damage, apoptosis and inflammatory response, and its mechanism of action was closely related to the activation of tyrosine kinase B (TrkB) receptor and inhibition of microglia activation. In animal experiments, P-TBDNF improved motor and cognitive deficits in MPTP mice and inhibited pathological changes in Parkinson's disease (PD). In conclusion, this paper is expected to reveal the mechanism of action of P-TBDNF in inhibiting neurotoxicity, provide a new way for treating PD, and lay the foundation for the future development of recombinant P-TBDNF.

Neuroprotection of Andrographolide against Neurotoxin MPP+-Induced Apoptosis in SH-SY5Y Cells via Activating Mitophagy, Autophagy, and Antioxidant Activities

Parkinson's disease (PD) is associated with dopaminergic neuron loss and alpha-synuclein aggregation caused by ROS overproduction, leading to mitochondrial dysfunction and autophagy impairment. Recently, andrographolide (Andro) has been extensively studied for various pharmacological properties, such as anti-diabetic, anti-cancer, anti-inflammatory, and anti-atherosclerosis. However, its potential neuroprotective effects on neurotoxin MPP⁺-induced SH-SY5Y cells, a cellular PD model, remain uninvestigated. In this study, we hypothesized that Andro has neuroprotective effects against MPP⁺-induced apoptosis, which may be mediated through the clearance of dysfunctional mitochondria by mitophagy and ROS by antioxidant activities. Herein, Andro pretreatment could attenuate MPP⁺-induced neuronal cell death that was reflected by reducing mitochondrial membrane potential (MMP) depolarization, alpha-synuclein, and pro-apoptotic proteins expressions. Concomitantly, Andro attenuated MPP⁺-induced oxidative stress through mitophagy, as indicated by increasing colocalization of MitoTracker Red with LC3, upregulations of the PINK1-Parkin pathway, and autophagy-related proteins. On the contrary, Andro-activated autophagy was compromised when pretreated with 3-MA. Furthermore, Andro activated the Nrf2/KEAP1 pathway, leading to increasing genes encoding antioxidant enzymes and activities. This study elucidated that Andro exhibited significant neuroprotective effects against MPP⁺-induced SH-SY5Y cell death in vitro by enhancing mitophagy and clearance of alpha-synuclein through autophagy, as well as increasing antioxidant capacity. Our results provide evidence that Andro could be considered a potential supplement for PD prevention.