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.

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.

Hesperidin ameliorates cognitive dysfunction, oxidative stress and apoptosis against aluminium chloride induced rat model of Alzheimer's disease.

BACKGROUND/AIMS: Deregulation of metal ion homeostasis has been assumed as one of the key factors in the progression of neurodegenerative diseases. Aluminium (Al) has been believed as a major risk factor for the cause and progression of Alzheimer's disease (AD). In our lab, we have previously reported that hesperidin, a citrus bioflavonoid reversed memory loss caused by aluminium intoxication through attenuating acetylcholine esterase activity and the expression of Amyloid ß biosynthesis related markers. Al has been reported to cause oxidative stress associated apoptotic neuronal loss in the brain. So in the present study, protective effect of hesperidin against aluminium chloride (AlCl3) induced cognitive impairment, oxidative stress and apoptosis was studied. METHODS: Male Wistar rats were divided into control, AlCl3 treated (100 mg/kg., b.w.), AlCl3 and hesperidin (100 mg/kg., b.w.) co-treated and hesperidin alone treated groups. In control and experimental rats, learning and memory impairment were measured by radial arm maze, elevated plus maze and passive avoidance tests. In addition, oxidative stress and expression of pro and anti-apoptotic markers were also evaluated. RESULTS: Intraperitoneal injection of AlCl3 (100 mg/kg., b.w.) for 60 days significantly enhanced the learning and memory deficits, levels of thiobarbituric acid reactive substances and the expression of Bax and diminished the levels of reduced glutathione, activities of enzymatic antioxidants and the expression of B-cell lymphoma-2 (Bcl-2) as compared to control group in the hippocampus, cortex, and cerebellum. Coadministration of hesperidin (100 mg/kg., b.w. oral) for 60 days prevented the cognitive deficits, biochemical anomalies and apoptosis induced by AlCl3 treatment. CONCLUSION: Results of the present study demonstrated that hesperidin could be a potential therapeutic agent in the treatment of oxidative stress and apoptosis associated neurodegenerative diseases including AD.