Microglial glutaminase 1 mediates chronic restraint stress-induced depression-like behaviors and synaptic damages

Dear Editor,Major depressive disorder(MDD)is one of the most common psychiatric illnesses that significantly increase the risk of suicide.1 Stress-triggered dysfunctions of microglia have been identified as a commonly occurred pathological feature of MDD.1–3 Microglial dysfunction contributes to the pathogenesis of MDD via immunoresponses/neuroinflammation-mediated neural damage and pathological synapse loss-mediated neural circuit disruption.1 Although the involvement of microglia in MDD has been widely investigated,the molecular mechanisms underlying microglial dysfunction remain largely unknown.Recently,we identified glutaminase 1(Gls1)as one key protein that participates in microglial dysfunction.4–6 Gls1 catalyzes the hydrolysis of glutamine to produce glutamate in the brain.4 Besides its well-known role in excitatory neurotoxicity,we found Gls1 up-regulation in microglia in animal models of Alzheimer’s disease and ischemic stroke.4,7 Gls1 activates microglia to overproduce cytokines and release inflammatory extracellular vesicles,therefore leading to neuroinflammation in animal models of Alzheimer’s disease and ischemic stroke.4–6 More importantly,Gls1 has been found to be up-regulated in the brains of MDD patients,and microglial Gls1 deficiency mitigated LPS-induced depression-like behaviors.8 However,LPS exposure is not an appropriate model to mimic MDD phenotypes,leaving the involvement of Gls1 in MDD an undetermined question.

Neural stem cell-derived extracellular vesicles mitigate Alzheimer’s disease-like phenotypes in a preclinical mouse model

Dear Editor,Alzheimer’s disease(AD)is the most common neurodegenerative disorder and the No.1 cause of dementia in elderly with no effective treatments.1 The application of stem cell-derived extracellular vesicles(EVs)has emerged as a promising therapeutic strategy for AD.2 EVs are small bilipid layer-enclosed vesicles that display blood-brain barrier(BBB)penetrating ability and similar potency to their parental cells.

Organosilicon polymer-derived ceramics: An overview

Polymer-derived ceramics(PDCs) strategy shows a great deal of advantages for the fabrication of advanced ceramics. Organosilicon polymers facilitate the shaping process and different silicon-based ceramics with controllable components can be fabricated by modifying organosilicon polymers or adding fillers. It is worth noting that silicate ceramics can also be fabricated from organosilicon polymers by the introduction of active fillers, which could react with the produced silica during pyrolysis. The organosilicon polymer-derived ceramics show many unique properties, which have attracted many attentions in various fields. This review summarizes the typical organosilicon polymers and the processing of organosilicon polymers to fabricate silicon-based ceramics, especially highlights the three-dimensional(3 D) printing technique for shaping the organosilicon polymerderived ceramics, which makes the possibility to fabricate silicon-based ceramics with complex structure. More importantly, the recent studies on fabricating typical non-oxide and silicate ceramics derived from organosilicon polymers and their biomedical applications are highlighted.