新生小牛脑蛋白对小鼠Astroglial细胞的作用

从新生小牛脑经提取、DEAE-Sephadex A-50和Sephadex G-100纯化,得到二个蛋白质(CBP_1和CBP_2),经SDS聚丙烯酰胺凝胶电泳测得其分子量分别为4.1万和2.4万。观察了CBP_1和CBP_2对体外培养的静止期Astroglial细胞的作用,结果表明,CBP_1和CBP_2均有刺激静止期Astroglial细胞增殖的作用,其中以CBP_2的作用更强,CBP_2的最佳刺激浓度为100μg/ml。CBP_2还能刺激该细胞DNA的合成,其DNA合成高峰在24h。

Disintegration of the Astroglial Domain Organization May Underlie the Loss of Reality Comprehension in Schizophrenia: A Hypothetical Model

A pathophysiological model of the loss of reality comprehension in schizophrenia is proposed. Based on a formalism it is hypothesized that astroglial domains exert an information-categorizing function which becomes progressively lost in the schizophrenic process, caused by functional and structural disintegration of astroglial domains. Unconstrained synaptic neurotransmission functionally disintegrates the astroglial domains. Microdomains located between perisynaptic astroglial processes and the synaptic membrane are interpreted as elementary functional units categorizing synaptic information processing. Unconstrained diffusion of neurotransmitters into the extrasynaptic space leads to the dysfunction of microdomain formation. In parallel, atrophic processes of astroglia progressively break up the connectivity between synaptic and extrasynaptic compartments disrupting astroglial domains. Basically, the organization of astroglia into definite functional and structural units (modules) of astroglial-synaptic information processing may enable the brain to comprehend ontological realms such as subjects and objects in the environment and their distinct qualities. This fundamental capability of cognition is lost in schizophrenia. It is suggested that this ontological confusion of astroglial domain boundaries progressively disorganizes reality comprehension and may represent the basic pathology in schizophrenia underlying the main symptoms of the disorder. Finally, the testing of the model is shortly discussed.

Emerging roles of astrocytes in blood-brain barrier disruption upon amyloid-beta insults in Alzheimer's disease

Blood-brain barrier disruption occurs in the early stages of Alzheimer’s disease.Recent studies indicate a link between blood-brain barrier dysfunction and cognitive decline and might accelerate Alzheimer’s disease progression.Astrocytes are the most abundant glial cells in the central nervous system with important roles in the structural and functional maintenance of the blood-brain barrier.For example,astrocytic cove rage around endothelial cells with perivascular endfeet and secretion of homeostatic soluble factors are two major underlying mechanisms of astrocytic physiological functions.Astrocyte activation is often observed in Alzheimer’s disease patients,with astrocytes expressing a high level of glial fibrillary acid protein detected around amyloid-beta plaque with the elevated phagocytic ability for amyloid-beta.Structural alte rations in Alzheimer’s disease astrocytes including swollen endfeet,somata shrinkage and possess loss contribute to disruption in vascular integrity at capillary and arte rioles levels.In addition,Alzheimer’s disease astrocytes are skewed into proinflammatory and oxidative profiles with increased secretions of vasoactive mediators inducing endothelial junction disruption and immune cell infiltration.In this review,we summarize the findings of existing literature on the relevance of astrocyte alte ration in response to amyloid pathology in the context of blood-brain barrier dysfunction.First,we briefly describe the physiological roles of astrocytes in blood-brain barrier maintenance.Then,we review the clinical evidence of astrocyte pathology in Alzheimer’s disease patients and the preclinical evidence in animal and cellular models.We further discuss the structural changes of blood-brain barrier that correlates with Alzheimer’s disease astrocyte.Finally,we evaluate the roles of soluble factors secreted by Alzheimer’s disease astrocytes,providing potential molecular mechanisms underlying blood-brain barrier modulation.We conclude with a perspective on investigating the therapeutic potential of targeting astrocytes for blood-brain barrier protection in Alzheimer’s disease.

Simulating traumatic brain injury in vitro:developing high throughput models to test biomaterial based therapies

Traumatic brain injuries are serious clinical incidents associated with some of the poorest outcomes in neurological practice.Coupled with the limited regenerative capacity of the brain,this has significant implications for patients,carers,and healthcare systems,and the requirement for life-long care in some cases.Clinical treatment currently focuses on limiting the initial neural damage with longterm care/support from multidisciplinary teams.Therapies targeting neuroprotection and neural regeneration are not currently available but are the focus of intensive research.Biomaterial-based interventions are gaining popularity for a range of applications including biomolecule and drug delive ry,and to function as cellular scaffolds.Experimental investigations into the development of such novel therapeutics for traumatic brain injury will be critically underpinned by the availability of appropriate high thro ughput,facile,ethically viable,and pathomimetic biological model systems.This represents a significant challenge for researchers given the pathological complexity of traumatic brain injury.Specifically,there is a concerted post-injury response mounted by multiple neural cell types which includes microglial activation and astroglial scarring with the expression of a range of growth inhibito ry molecules and cytokines in the lesion environment.Here,we review common models used for the study of traumatic brain injury(ranging from live animal models to in vitro systems),focusing on penetrating traumatic brain injury models.We discuss their relative advantages and drawbacks for the developmental testing of biomaterial-based therapies.

Immortalized hippocampal astrocytes from 3xTg-AD mice,a new model to study disease-related astrocytic dysfunction:a comparative review

Alzheimer's disease(AD)is characterized by complex etiology,long-lasting pathogenesis,and celltype-specific alterations.Currently,there is no cure for AD,emphasizing the urgent need for a comprehensive understanding of cell-specific pathology.Astrocytes,principal homeostatic cells of the central nervous system,are key players in the pathogenesis of neurodegenerative diseases,including AD.Cellular models greatly facilitate the investigation of cell-specific pathological alterations and the dissection of molecular mechanisms and pathways.Tumor-derived and immortalized astrocytic cell lines,alongside the emerging technology of adult induced pluripotent stem cells,are widely used to study cellular dysfunction in AD.Surprisingly,no stable cell lines were available from genetic mouse AD models.Recently,we established immortalized hippocampal astroglial cell lines from amyloid-βprecursor protein/presenilin-1/Tau triple-transgenic(3xTg)-AD mice(denominated as wild type(WT)-and 3Tg-iAstro cells)using retrovirus-mediated transduction of simian virus 40 large T-antigen and propagation without clonal selection,thereby maintaining natural heterogeneity of primary cultures.Several groups have successfully used 3Tg-iAstro cells for single-cell and omics approaches to study astrocytic AD-related alterations of calcium signaling,mitochondrial dysfunctions,disproteostasis,altered homeostatic and signaling support to neurons,and blood-brain barrier models.Here we provide a comparative overview of the most used models to study astrocytes in vitro,such as primary culture,tumor-derived cell lines,immortalized astroglial cell lines,and induced pluripotent stem cell-derived astrocytes.We conclude that immortalized WT-and 3Tg-iAstro cells provide a noncompetitive but complementary,low-cost,easy-to-handle,and versatile cellular model for dissection of astrocyte-specific AD-related alterations and preclinical drug discovery.