Evaluation of the effects of the T-type calcium channel enhancer SAK3 in a rat model of TAF1 deficiency.

The TATA-box binding protein associated factor 1 (TAF1) is part of the TFIID complex that plays a key role during the initiation of transcription. Variants of TAF1 are associated with neurodevelopmental disorders. Previously, we found that CRISPR/Cas9 based editing of the TAF1 gene disrupts the morphology of the cerebral cortex and blunts the expression as well as the function of the CaV3.1 (T-type) voltage gated calcium channel. Here, we tested the efficacy of SAK3 (ethyl 8'-methyl-2', 4-dioxo-2-(piperidin-1-yl)-2'H-spiro [cyclopentane-1, 3'-imidazo [1, 2-a] pyridine]-2-ene-3-carboxylate), a T-type calcium channel enhancer, in an animal model of TAF1 intellectual disability (ID) syndrome. At post-natal day 3, rat pups were subjected to intracerebroventricular (ICV) injection of either gRNA-control or gRNA-TAF1 CRISPR/Cas9 viruses. At post-natal day 21, the rat pups were given SAK3 (0.25 mg/kg, p.o.) or vehicle for 14 days (i.e. till post-natal day 35) and then subjected to behavioral, morphological, and molecular studies. Oral administration of SAK3 (0.25 mg/kg, p.o.) significantly rescued locomotion abnormalities associated with TAF1 gene editing. SAK3 treatment prevented the loss of cortical neurons and GFAP-positive astrocytes observed after TAF1 gene editing. In addition, SAK3 protected cells from apoptosis. SAK3 also restored the Brain-derived neurotrophic factor/protein kinase B/Glycogen Synthase Kinase 3 Beta (BDNF/AKT/GSK3ß) signaling axis in TAF1 edited animals. Finally, SAK3 normalized the levels of three GSK3ß substrates - CaV3.1, FOXP2, and CRMP2. We conclude that the T-type calcium channel enhancer SAK3 is beneficial against the deleterious effects of TAF1 gene-editing, in part, by stimulating the BDNF/AKT/GSK3ß signaling pathway.

Neuroprotective effect of Demethoxycurcumin, a natural derivative of Curcumin on rotenone induced neurotoxicity in SH-SY 5Y Neuroblastoma cells.

BACKGROUND: Mitochondrial dysfunction and oxidative stress are the main toxic events leading to dopaminergic neuronal death in Parkinson's disease (PD) and identified as vital objective for therapeutic intercession. This study investigated the neuro-protective effects of the demethoxycurcumin (DMC), a derivative of curcumin against rotenone induced neurotoxicity. METHODS: SH-SY5Y neuroblastoma cells are divided into four experimental groups: untreated cells, cells incubated with rotenone (100 nM), cells treated with DMC (50 nM) + rotenone (100 nM) and DMC alone treated. 24 h after treatment with rotenone and 28 h after treatment with DMC, cell viability was assessed using the MTT assay, and levels of ROS and MMP, plus expression of apoptotic protein were analysed. RESULTS: Rotenone induced cell death in SH-SY5Y cells was significantly reduced by DMC pretreatment in a dose-dependent manner, indicating the potent neuroprotective effects of DMC. Rotenone treatment significantly increases the levels of ROS, loss of MMP, release of Cyt-c and expression of pro-apoptotic markers and decreases the expression of anti-apoptotic markers. CONCLUSIONS: Even though the results of the present study indicated that the DMC may serve as a potent therapeutic agent particularly for the treatment of neurodegenerative diseases like PD, further pre-clinical and clinical studies are required.

Chronic mild stress augments MPTP induced neurotoxicity in a murine model of Parkinson's disease.

Depression is frequently encountered during Parkinson's disease (PD) as a non-motor feature, which has been reported to cause and exaggerate motor deficits and neurodegenerative events in experimental PD models. We studied the effect of chronic mild stress (CMS) (pre, post and pre & post) exposure mediated depression on motor and non-motor symptoms, oxidative stress, inflammation and brain derived neurotrophic factor (BDNF) levels and its related signalling molecules against the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine/probenecid (MPTP/p) induced neurotoxicity in mice. CMS and MPTP/p-coexposed C57BL/6 mice exhibited low neuromuscular strength and stride length with enhanced oxidative stress and inflammation as compared to CMS or MPTP/p alone exposed mice. Coexposure diminished the levels of BDNF and expressions of p-TrkB, p-ERK/ERK, p-AKT/AKT and p-CREB in nigrostriatal regions as compared to those of the alone exposure. CMS alone exposed mice showed more anxiety related behaviour with diminished expression of serotonin transporter as compared to MPTP/p alone injected group. Post-stress exposure to MPTP/p mice exhibited lowest motor and reflecting higher anxiety state with greatest enhancement in inflammation and reduction in the protein expression of stress and cell signalling markers as compared to pre and pre & post stress exposed PD mice. However, pre- and pre & post CMS exposed PD animals are more vulnerable to oxidative stress as compared with post-stress experienced MPTP/p mice. CMS mediated depression exacerbates motor/non-motor symptoms in MPTP/p-PD animals by modulating oxidative stress and various signalling molecules. Our results suggested that stress induced NMS can accelerate neurodegenerative processes in the PD in a progressive or expedited manner.

Neurosupportive Role of Vanillin, a Natural Phenolic Compound, on Rotenone Induced Neurotoxicity in SH-SY5Y Neuroblastoma Cells.

Vanillin, a phenolic compound, has been reported to offer neuroprotection against experimental Huntington's disease and global ischemia by virtue of its antioxidant, anti-inflammatory, and antiapoptotic properties. The present study aims to elucidate the underlying neuroprotective mechanism of vanillin in rotenone induced neurotoxicity. Cell viability was assessed by exposing SH-SY5Y cells to various concentrations of rotenone (5-200 nM) for 24 h. The therapeutic effectiveness of vanillin against rotenone was measured by pretreatment of vanillin at various concentrations (5-200 nM) and then incubation with rotenone (100 nM). Using effective dose of vanillin (100 nM), mitochondrial membrane potential, levels of reactive oxygen species (ROS), and expression patterns of apoptotic markers were assessed. Toxicity of rotenone was accompanied by the loss of mitochondrial membrane potential, increased ROS generation, release of cyt-c, and enhanced expressions of proapoptotic and downregulation of antiapoptotic indices via the upregulation of p38 and JNK-MAPK pathway proteins. Our results indicated that the pretreatment of vanillin attenuated rotenone induced mitochondrial dysfunction, oxidative stress, and apoptosis. Thus, vanillin may serve as a potent therapeutic agent in the future by virtue of its multiple pharmacological properties in the treatment of neurodegenerative diseases including PD.

Dietary Supplementation of Walnut Partially Reverses 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine Induced Neurodegeneration in a Mouse Model of Parkinson's Disease.

Numerous studies indicating that natural plant sources and their active phytochemicals offer protection to the pathological processes related to the development of neurogenerative diseases including Parkinson's disease (PD). In the present study, the neuro protective efficacy of dietary supplementation of walnut (6 %) for 28 days was examined in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) (i.p., 20 mg/kg body weight/day) for last four consecutive days. MPTP injection diminished the levels of GSH, dopamine and metabolites along with decreased activities of GPx and mitochondrial complex I. Further, the levels of TBARS and enzymatic antioxidants such as SOD and catalase, MAO-B activities were enhanced by MPTP treatment. Behavioral deficits and lowered TH expression are also proved MPTP induced neurotoxicity. Dietary supplementation of walnut attenuated MPTP-induced impairment in PD mice might be by its MAO-B inhibitory, antioxidant and mitochondrial protective actions. To find out the exact mechanism of action walnut on PD mice warrants further extensive studies.

CNB-001, a novel pyrazole derivative mitigates motor impairments associated with neurodegeneration via suppression of neuroinflammatory and apoptotic response in experimental Parkinson's disease mice.

Parkinson's disease (PD) is characterized by the progressive degeneration via apoptosis of nigrostriatal dopaminergic neurons associated with inflammation, resulting in behavioral anomalies. Therefore, an anti-apoptotic and anti-inflammatory regimen may be useful in treatment of PD. CNB-001, a novel pyrazole derivative of curcumin and cyclohexyl bisphenol A has superior biological properties than its parental compounds. The present study utilizes a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) model of PD to investigate anti-inflammatory and anti-apoptotic mediated neuroprotection of CNB-001. The administration of MPTP (30 mg/kg for four successive days) significantly induced motor impairments as determined by behavioral studies (narrow beam test, catalepsy and akinesia), lowered dopamine levels and up-regulated the expressions of the inflammatory and apoptotic markers (tumor necrosis factor-alpha, interleukin-1ß, interleukin-6, inducible nitric oxide synthase, glial fibrillary acidic protein, cyclooxygenase-2 and Bax). Moreover, MPTP treatment attenuated Bcl-2 and nigrostriatal dopamine transporter expression and also increased total nitrite and citrulline levels in comparison to the control group. However, co-treatment with CNB-001 significantly attenuated motor impairments and pathological changes caused by MPTP administration. Collectively, our results demonstrate that CNB-001 is neuroprotective through its anti-inflammatory and anti-apoptotic properties. Thus, CNB-001 has potential to be further developed as a therapeutic candidate for treatment of PD.