Browsing by Subject "NEURAL STEM-CELLS"
Now showing items 1-7 of 7
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(2017)The purpose of this study was to examine the neurorestorative effect of delayed 9 cis retinoic acid (9cRA) treatment for stroke. Adult male rats received a 90-min right distal middle cerebral artery occlusion (dMCAo). Animals were separated into two groups with similar infarction sizes, based on magnetic resonance imaging on day 2 after dMCAo. 9cRA or vehicle was given via an intranasal route daily starting from day 3. Stroke rats receiving 9cRA post-treatment showed an increase in brain 9cRA levels and greater recovery in motor function. 9cRA enhanced the proliferation of bromodeoxyuridine (+) cells in the subventricular zone (SVZ) and lesioned cortex in the stroke brain. Using subventricular neurosphere and matrigel cultures, we demonstrated that proliferation and migration of SVZ neuroprogenitor cells were enhanced by 9cRA. Our data support a delayed and non-invasive drug therapy for stroke. Intranasal 9cRA can facilitate the functional recovery and endogenous repair in the ischemic brain.
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(2020)Liposome is one of the most commonly used drug delivery systems in the world, due to its excellent biocompatibility, satisfactory ability in controlling drug release, and passive targeting capability. However, some drawbacks limit the application of liposomes in clinical, such as problems in transporting, storing, and difficulties in maintaining the drug concentration in the local area. Scaffolds usually are used as implants to supply certain mechanical supporting to the defective area or utilized as diagnosis and imaging methods. But, in general, unmodified scaffolds show limited abilities in promoting tissue regeneration and treating diseases. Therefore, liposome-scaffold composite systems are designed to take advantages of both liposomes’ biocompatibility and scaffolds’ strength to provide a novel system that is more suitable for clinical applications. This review introduces and discusses different types of liposomes and scaffolds, and also the application of liposome-scaffold composite systems in different diseases, such as cancer, diabetes, skin-related diseases, infection and human immunodeficiency virus, and in tissue regeneration like bone, teeth, spinal cord and wound healing.
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(2021)Cystatin B (CSTB) acts as an inhibitor of cysteine proteases of the cathepsin family and loss-of-function mutations result in human brain diseases with a genotype-phenotype correlation. In the most severe case, CSTB-deficiency disrupts brain development, and yet the molecular basis of this mechanism is missing. Here, we establish CSTB as a regulator of chromatin structure during neural stem cell renewal and differentiation. Murine neural precursor cells (NPCs) undergo transient proteolytic cleavage of the N-terminal histone H3 tail by cathepsins B and L upon induction of differentiation into neurons and glia. In contrast, CSTB-deficiency triggers premature H3 tail cleavage in undifferentiated self-renewing NPCs and sustained H3 tail proteolysis in differentiating neural cells. This leads to significant transcriptional changes in NPCs, particularly of nuclear-encoded mitochondrial genes. In turn, these transcriptional alterations impair the enhanced mitochondrial respiration that is induced upon neural stem cell differentiation. Collectively, our findings reveal the basis of epigenetic regulation in the molecular pathogenesis of CSTB deficiency.
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(2020)Generation of new neurons by utilizing the regenerative potential of adult neural stem cells (NSCs) and neuroblasts is an emerging therapeutic strategy to treat various neurodegenerative diseases, including neuronal loss after stroke. Committed to neuronal lineages, neuroblasts are differentiated from NSCs and have a lower proliferation rate. In stroke the proliferation of the neuroblasts in the neurogenic areas is increased, but the limiting factor for regeneration is the poor survival of migrating neuroblasts. Survival of neuroblasts can be promoted by small molecules; however, new drug delivery methods are needed to specifically target these cells. Herein, to achieve specific targeting, we have engineered biofunctionalized porous silicon nanoparticles (PSi NPs) conjugated with a specific antibody against polysialylated neural cell adhesion molecule (PSA-NCAM). The PSi NPs loaded with a small molecule drug, SC-79, were able to increase the activity of the Akt signaling pathway in doublecortin positive neuroblasts both in cultured cells and in vivo in the rat brain. This study opens up new possibilities to target drug effects to migrating neuroblasts and facilitate differentiation, maturation and survival of developing neurons. The conjugated PSi NPs are a novel tool for future studies to develop new therapeutic strategies aiming at regenerating functional neurocircuitry after stoke.
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(2020)New neurons are generated in the postnatal rodent hypothalamus, with a subset of tanycytes in the third ventricular (3V) wall serving as neural stem/progenitor cells. However, the precise stem cell niche organization, the intermediate steps and the endogenous regulators of postnatal hypothalamic neurogenesis remain elusive. Quantitative lineage-tracing in vivo revealed that conditional deletion of fibroblast growth factor 10 (Fgf10) from Fgf10-expressing beta-tanycytes at postnatal days (P)4-5 results in the generation of significantly more parenchymal cells by P28, composed mostly of ventromedial and dorsomedial neurons and some glial cells, which persist into adulthood. A closer scrutiny in vivo and ex vivo revealed that the 3V wall is not static and is amenable to cell movements. Furthermore, normally beta-tanycytes give rise to parenchymal cells via an intermediate population of alpha-tanycytes with transient amplifying cell characteristics. Loss of Fgf10 temporarily attenuates the amplification of beta-tanycytes but also appears to delay the exit of their alpha-tanycyte descendants from the germinal 3V wall. Our findings suggest that transience of cells through the alpha-tanycyte domain is a key feature, and Fgf10 is a negative regulator of postnatal hypothalamic neurogenesis.
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(2021)Neurogenesis in the adult hippocampus declines with age, a process that has been implicated in cognitive and emotional impairments. However, the mechanisms underlying this decline have remained elusive. Here, we show that the age-dependent downregulation of lamin B1, one of the nuclear lamins in adult neural stem/progenitor cells (ANSPCs), underlies age-related alterations in adult hippocampal neurogenesis. Our results indicate that higher levels of lamin B1 in ANSPCs safeguard against premature differentiation and regulate the maintenance of ANSPCs. However, the level of lamin B1 in ANSPCs declines during aging. Precocious loss of lamin B1 in ANSPCs transiently promotes neurogenesis but eventually depletes it. Furthermore, the reduction of lamin B1 in ANSPCs recapitulates age-related anxiety-like behavior in mice. Our results indicate that the decline in lamin B1 underlies stem cell aging and impacts the homeostasis of adult neurogenesis and mood regulation.
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(2020)Different types of carbon materials are biocompatible with neural cells and can promote maturation. The mechanism of this effect is not clear. Here we have tested the capacity of a carbon material composed of amorphous sp3 carbon backbone, embedded with a percolating network of sp2 carbon domains to sustain neuronal cultures. We found that cortical neurons survive and develop faster on this novel carbon material. After 3 days in culture, there is a precocious increase in the frequency of neuronal activity and in the expression of maturation marker KCC2 on carbon films as compared to a commonly used glass surface. Accelerated development is accompanied by a dramatic increase in neuronal dendrite arborization. The mechanism for the precocious maturation involves the activation of intracellular calcium oscillations by the carbon material already after 1 day in culture. Carbon-induced oscillations are independent of network activity and reflect intrinsic spontaneous activation of developing neurons. Thus, these results reveal a novel mechanism for carbon material-induced neuronal survival and maturation.
