ABSTRACT
ObjectiveTo construct a neural network-like tissue with the potential of synaptic formation in vitro by seeding human induced pluripotent stem cell-derived neural precursor cells （hiPSC-NPCs） on decellularized optic nerve （DON）， so as to provide a promising approach for repair of nerve tissue injury. MethodsThrough directional induction and tissue engineering technology， human induced pluripotent stem cells （hiPSCs） and 3D DON scaffolds were combined to construct neural network-like tissues. Then the hiPSCs were directionally induced into human neural precursor cells （hNPCs） and neurons. Immunofluorescence staining was used to identify cell differentiation efficiency. 3D DON scaffolds were prepared. Morphology and cytocompatibility of scaffolds were identified by scanning electron microscopy and Tunnel staining. Induced hiPSC-NPCs were seeded on DON scaffolds. Immunofluorescence staining， scanning electron microscopy， transmission electron microscopy and patch clamp were used to observe the morphology and functional identification of constructed neural network tissues. Results①The results of immunofluorescence staining suggested that most of hiPSC-NPCs differentiated into neurons in vitro. We had successfully constructed a neural network dominated by neurons. ② The results of scanning electron microscopy and immunohistochemistry suggested that a neural network-like tissue with predominating excitatory neurons in vitro was successfully constructed. ③The results of immunohistochemical staining， transmission electron microscopy and patch clamp indicated that the neural network-like tissue had synaptic transmission function. ConclusionA neural network-like tissue mainly composed of excitatory neurons has been constructed by the combination of natural uniform-channel DON scaffold and hiPSC-NPCs， which has the function of synaptic transmission. This neural network plays a significant role in stem cell derived replacement therapy， and offers a promising prospect for repair of spinal cord injury （SCI） and other neural tissue injuries.
ABSTRACT
Anxiety disorders are currently a major psychiatric and social problem, the mechanisms of which have been only partially elucidated. The hippocampus serves as a major target of stress mediators and is closely related to anxiety modulation. Yet so far, its complex anatomy has been a challenge for research on the mechanisms of anxiety regulation. Recent advances in imaging, virus tracking, and optogenetics/chemogenetics have permitted elucidation of the activity, connectivity, and function of specific cell types within the hippocampus and its connected brain regions, providing mechanistic insights into the elaborate organization of the hippocampal circuitry underlying anxiety. Studies of hippocampal neurotransmitter systems, including glutamatergic, GABAergic, cholinergic, dopaminergic, and serotonergic systems, have contributed to the interpretation of the underlying neural mechanisms of anxiety. Neuropeptides and neuroinflammatory factors are also involved in anxiety modulation. This review comprehensively summarizes the hippocampal mechanisms associated with anxiety modulation, based on molecular, cellular, and circuit properties, to provide tailored targets for future anxiety treatment.
Subject(s)
Humans , Hippocampus/physiology , Anxiety , Anxiety Disorders , Neurotransmitter Agents , NeuropeptidesABSTRACT
OBJECTIVE: To observe the effect of electroacupuncture (EA) stimulation of "Zusanli"(ST36)on gastric function (food consumption and gastric emptying rate) and excitability of hippocampal glutamatergic neurons in mice, so as to explore its mechanism underlying enhancing gastrointestinal function. METHODS: The present study includes 2 parts. 1) C57BL/6 mice were randomly divided into normal and EA groups (n=12 in each group). EA (2 Hz/15 Hz, 1-3 mA) was applied to bilateral ST36 for 20 min, once daily for 7 days. In each group, 6 mice were used to measure the food consumption and gastric emptying rate, and the other 6 mice used to detect the hippocampal glutamate secretion content by using in vivo microdialysis and high performance liquid chromatography. 2) Thirty CaMKIIα-Cre mice received microinjection of a recombinant adeno-associated viral vector containing inhibitory designer receptor exclusively activated by a designer drug (DREADD, AAV-DIO-hM4Di-eYFP) into the hippocampus. Twenty-one days later, 3 mice were selected to observe the expression of eYFP-labeled hM4Di by immunohistochemistry, and 15 mice employed to observe the electrical activities of hM4Di-eYFP positive neurons exposed in chemogenetic activating drug Clozapine N-oxide (CNO) perfusion conditions (n=3) and without CNO in the recording chamber (n=6 in the control and EA groups) by using whole cell patch clamp. The rest 12 CaMKII-Cre mice were equally randomized into AAV-DIO-hM4Di-eYFP+CNO group and AAV-DIO-hM4Di-eYFP+CNO+EA group, and CNO was given by intraperitoneal injection for observing the effect of EA on gastric function. RESULTS: 1) In C57BL/6 mice, compared with the normal group, the food consumption, gastric emptying rate, and the glutamate content in the hippocampus were obviously increased in the EA group (P0.05), suggesting an elimination of EA effect after acute DREADD-mediated activation of the CaMKIIα-positive hippocampal excitatory neurons. CONCLUSION: EA at ST36 can promote food intake and gastric emptying in normal mice but not in CaMKIIα-Cre mice with activated hippocampal hM4Di receptors，suggesting a contribution of the CaMKIIα-positive hippocampal excitatory neurons (glutamatergic neurons in particular) to the enhanced gastrointestinal function of EA at ST36.