Directed Differentiation Of Human Induced Pluripotent Stem Cell And The Therapeutic Effects On Alzheimer Transgenic Mice

Background: Degenerative disease occurs in the neural network in the AD brain and there are reports of loss of different types of neurons in some brain areas(controversial)or dysfunction(such as GABAergic,cholinergic).Due to the non-renewability of most brain regions and most types of neurons,it can be expected that traditional drug therapy will have very limited effects in replenishing lost neurons and reconstructing degenerated neural networks.Inducing the regeneration of specific types of neurons in AD diseased brain regions is a potential treatment strategy.Compared with the use of drugs,behavior,neurostimulation and other methods to enhance endogenous hippocampal neurogenesis(limited to the dentate gyrus,the number is too small,and only granular cells can be produced),through transplantation of neural stem cells,iPSCs,and induced differentiation Neural precursor cells,embryonic neurons,etc.,exogenous means to induce neurogenesis and neural network reconstruction have more room for manipulation in terms of brain area,neuron type and number,and transplantation time.There have been many research attempts to treat AD through cell transplantation,including transplantation of embryonic stem cells,human or murine neural stem cells,mesenchymal stem cells(including a phase Ⅰ clinical trial),iPSC,and iPSC-induced neural precursor cells,IPSC-induced cholinergic neurons,GABAergic neural precursor cells;transplantation methods include direct intracerebral injection,intravenous injection or intranasal injection,etc.These studies have reported that cell transplantation has a certain alleviating effect on AD,including alleviating inflammation,reducing Aβ,and improving learning and memory.However,the current level of research on cell replacement therapy for AD is uneven.At least in animal experiments,there is still a long way to go before the neural network can be reconstructed through cell transplantation.Recent studies of our group have found that the accumulation of tau protein in GABAergic interneurons in the hippocampal dentate gyrus can lead to neurogenesis disorders,and supplementation of GABA or GABAergic agonists(Gaboxadol hydrochloride,THIP)can rescue the hippocampus caused by tau protein aggregation.Objective: This study aims to optimize the differentiation and maturation steps of stem cells,so that pluripotent stem cells can differentiate into specific neuron types(GABAergic neurons),to improve the method of transplanting neurons into the brain of AD mice and to ensure that the transplanted cells are normal survival,explore the cognitive and behavioral changes of AD mice after stem cell transplantation and provide evidence support for stem cell treatment of AD.Methods: By adjusting the small molecules and/or protein components of the culture medium,the stem cells were induced to differentiate into GABAergic neurons;GABAergic neurons were transplanted into the hippocampal CA1 area of AD model mice or GABAergic neurons by stereotaxic transplantation and THIP combined with stereotactic injection;using open field experiment,new object recognition experiment,situational fear,water maze and other techniques to detect the learning and memory ability of AD model mice.Results: The steps for the directed differentiation of human induced pluripotent stem cells into GABAergic interneurons were simplified;GABAergic interneurons transplanted for 1 week could not be judged whether they were alive,and transplanted GABAergic interneurons could successfully survive and survive 6 weeks later Integrated into the hippocampal CA1 area of APP/PS1 mice;THIP combined with transplantation of neural stem cells can improve the memory of APP/PS1 mice.Conclusion: GABAergic interneurons can survive and integrate into the neural network of mice,which can improve the learning and memory impairment of AD mice to a certain extent.THIP combined with stem cell transplantation can accelerate the improvement of memory impairment in AD mice.