Activation of ephrinb1/EPHB2/MAP-2/NMDAR Mediates Hippocampal Neurogenesis Promoted by Transcranial Direct Current Stimulation in Cerebral-Ischemic Mice

Synthesis and biological evaluation of novel pyrrolo[2,3-b]pyridine derivatives as potent GSK-3β inhibitors for treating Alzheimer's disease

The development of potent glycogen synthase kinase-3β (GSK-3β) inhibitor has been increasingly recognized as the candidate treatment against the multifactorial pathogenic mechanism of Alzheimer's disease (AD). This study prepared various new pyrrolo[2,3-b]pyridine derivatives, evaluated the anti-AD activities and detected the security based on the structure-guided rational design. Our results indicated that many pyrrolo[2,3-b]pyridine derivatives had strong GSK-3β inhibitory activities, particularly compounds 41, 46 and 54, with the half maximal inhibitory concentrations (IC50) of 0.22, 0.26 and 0.24 nM, respectively, and each of them generally possessed GSK-3β selectivity over 24 structurally similar kinases. In addition, further targeting studies at the cellular level revealed that compound 41 increased GSK-3β phosphorylation at Ser9 site dose-dependently for inhibiting GSK-3β activity, therefore inhibiting the hyperphosphorylation of tau protein by decreasing the p-tau-Ser396 abundance. Moreover, 41 up-regulated β-catenin and neurogenesis-related markers (GAP43 and MAP-2), thereby promoting neurite outgrowth of neurons in SH-SY5Y cells. According to the in vitro cells assay, 41 showed the lower cytotoxicity to SH-SY5Y cells with a survival rate of over 70 % at the concentration of 100 μM. In vivo efficacy and acute toxicity experiments showed that, 41 effectively ameliorated the dyskinesia in AlCl3-induced zebrafish AD models and exhibited its low-toxicity nature in C57BL/6 mice. Overall, the pyrrolo[2,3-b]pyridine derivative 41 could serve as a promising GSK-3β inhibitor for treating AD.

Emerging Pro-neurogenic Therapeutic Strategies for Neurodegenerative Diseases: A Review of Pre-clinical and Clinical Research

The neuroscience community has largely accepted the notion that functional neurons can be generated from neural stem cells in the adult brain, especially in two brain regions: the subventricular zone of the lateral ventricles and the subgranular zone in the dentate gyrus of the hippocampus. However, impaired neurogenesis has been observed in some neurodegenerative diseases, particularly in Alzheimer's, Parkinson's, and Huntington's diseases, and also in Lewy Body dementia. Therefore, restoration of neurogenic function in neurodegenerative diseases emerges as a potential therapeutic strategy to counteract, or at least delay, disease progression. Considering this, the present study summarizes the different neuronal niches, provides a collection of the therapeutic potential of different pro-neurogenic strategies in pre-clinical and clinical research, providing details about their possible modes of action, to guide future research and clinical practice.

Non-invasive brain stimulation for functional recovery in animal models of stroke: A systematic review

Motor and cognitive dysfunction occur frequently after stroke, severely affecting a patient´s quality of life. Recently, non-invasive brain stimulation (NIBS) has emerged as a promising treatment option for improving stroke recovery. In this context, animal models are needed to improve the therapeutic use of NIBS after stroke. A systematic review was conducted based on the PRISMA statement. Data from 26 studies comprising rodent models of ischemic stroke treated with different NIBS techniques were included. The SYRCLE tool was used to assess study bias. The results suggest that both repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) improved overall neurological, motor, and cognitive functions and reduced infarct size both in the short- and long-term. For tDCS, it was observed that either ipsilesional inhibition or contralesional stimulation consistently led to functional recovery. Additionally, the application of early tDCS appeared to be more effective than late stimulation, and tDCS may be slightly superior to rTMS. The optimal stimulation protocol and the ideal time window for intervention remain unresolved. Future directions are discussed for improving study quality and increasing their translational potential.

Salidroside Alleviates Diabetic Cognitive Dysfunction Via B3galt2/F3/Contactin Signaling Pathway in Mice

Diabetes is frequently accompanied by cognitive impairment with insidious onset, and progressive cognitive and behavioral changes. β-1, 3-galactosyltransferase 2 (B3galt2) contributes to glycosylation, showing a clue for neuronal apoptosis, proliferation and differentiation. However, the role of B3galt2 in diabetic cognitive dysfunction (DCD) has not been investigated. In the present study, we aimed to explore the role of B3galt2 in DCD. Additionally, the potential therapeutic effects of salidroside on DCD was also explored. Diabetic C57BL/6J mice showed cognitive dysfunction together with down-regulated B3galt2. Overexpression of B3galt2 reversed the cognitive decline of diabetic C57BL/6J. Moreover, cognitive impairment was aggravated in B3galt2^+/- diabetic mice compared with C57BL/6J diabetic mice. Immunohistochemistry fluorescence indicated that B3galt2 and F3/Contactin were co-localized in the hippocampal regions. Importantly, the expression of F3/Contactin can be regulated by the manipulation of B3galt2, overexpression of which assuaged hippocampal neuronal damage, protected the synapsin, and reduced neuronal apoptosis in diabetic mice. Interestingly, SAL alleviated DCD and reversed the expression of B3galt2 in diabetic C57BL/6J mice. These findings indicate that inhibition of B3galt2/F3/Contactin pathway contributes to DCD, and participates in SAL reversed DCD.

Combination effects of mesenchymal stem cells transplantation and anodal transcranial direct current stimulation on a cuprizone-induced mouse model of multiple sclerosis

Multiple sclerosis (MS) has no absolute treatment, and researchers are still exploring to introduce promising therapy for MS. Transcranial direct current stimulation (tDCS), is a safe, non-invasive procedure for brain stimulating which can enhance working memory, cognitive neurohabitation and motor recovery. Here, we evaluated the effects of tDCS treatment and Mesenchymal stem cells (MSCs) transplantation on remyelination ability of a Cuprizone (CPZ)-induced demyelination mouse model. tDCS significantly increased the motor coordination and balance abilities in CPZ + tDCS and CPZ + tDCS + MSCs mice in comparison to the CPZ mice. Luxol fast blue (LFB) staining showed that tDCS and MSCs transplantation could increase remyelination capacity in CPZ + tDCS and CPZ + MSCs mice compared to the CPZ mice. But, the effect of tDCS with MSCs transplantation on remyelination process was larger than each of treatment alone. Immunofluorescence technique indicated that the numbers of Olig2⁺ cells were increased by tDCS and MSCs transplantation in CPZ + tDCS and CPZ + MSCs mice compared to the CPZ mice. Interestingly, the combination effect of tDCS and MSCs was larger than each of treatment alone on Oligodendrocytes population. MSCs transplantation significantly decreased the TUNEL⁺ cells in CPZ + MSCs and CPZ + tDCS + MSCs mice in comparison to the CPZ mice. Also, the combination effects of tDCS and MSCs transplantation was much larger than each of treatment alone on increasing the mRNA expression of BDNF and Sox2, while decreasing P53 as compared to CPZ mice. It can be concluded that the combination usage of tDCS and MSCs transplantation enhance remyelination process in CPZ-treated mice by increasing transplanted stem cell homing, oligodendrocyte generation and decreasing apoptosis.

Vitamin D as a modifiable risk factor, predictor, and theoretical therapeutic agent for vasospasm in spontaneous subarachnoid hemorrhage

Delayed deterioration associated with cerebral vasospasm (CVS) is a feared complication after spontaneous subarachnoid hemorrhage (SAH) and is one of the leading causes of death in patients with intracranial hemorrhage. The pathophysiology of vasospasm is complex and not fully understood, involving multiple inflammatory pathways in addition to vasoconstriction induced ischemia. Current treatment with anti-inflammatory or vasodilatory medications has been met with limited success and has not led to a decrease in vasospastic associated mortality prompting continued investigation of potential treatment options. The active form of vitamin D, 1,25-dihydroxyvitamin D₃ (1,25-VitD3), is a hormone with downstream effects that induce anti-inflammatory pathways, promote nitric oxide (NO) induced vasodilation, and lead to neuroprotective-gene expression, which may be useful in mitigating the vascular pathogenesis associated with CVS. A high prevalence of vitamin D deficiency has been identified in patients admitted with SAH. Low vitamin D levels in patients, as determined by time of year, has also been correlated to an increased incidence and severity of CVS. Further, the therapeutic usefulness of 1,25-VitD3 has been demonstrated in animal models leading to a decreased incidence of CVS but has yet to be thoroughly investigated in human studies. In this review, we will discuss the findings that suggest the potential of utilizing vitamin D as a predictive indicator, method of prevention, and or treatment option for CVS in patients following spontaneous SAH.

Roles of N-Methyl-D-Aspartate Receptors (NMDARs) in Epilepsy

Epilepsy is one of the most common neurological disorders characterized by recurrent seizures. The mechanism of epilepsy remains unclear and previous studies suggest that N-methyl-D-aspartate receptors (NMDARs) play an important role in abnormal discharges, nerve conduction, neuron injury and inflammation, thereby they may participate in epileptogenesis. NMDARs belong to a family of ionotropic glutamate receptors that play essential roles in excitatory neurotransmission and synaptic plasticity in the mammalian CNS. Despite numerous studies focusing on the role of NMDAR in epilepsy, the relationship appeared to be elusive. In this article, we reviewed the regulation of NMDAR and possible mechanisms of NMDAR in epilepsy and in respect of onset, development, and treatment, trying to provide more evidence for future studies.