Adult Mouse Subventricular Zone Stem and Progenitor Cells Are Sessile and Epidermal Growth Factor Receptor Negatively Regulates Neuroblast Migration

Background: The adult subventricular zone (SVZ) contains stem and progenitor cells that generate neuroblasts throughout life. Although it is well accepted that SVZ neuroblasts are migratory, recent evidence suggests their progenitor cells may also exhibit motility. Since stem and progenitor cells are proliferative and multipotential, if they were also able to move would have important implications for SVZ neurogenesis and its potential for repair. Methodology/Principal Findings: We studied whether SVZ stem and/or progenitor cells are motile in transgenic GFP+ slices with two photon time lapse microscopy and post hoc immunohistochemistry. We found that stem and progenitor cells; mGFAP-GFP+ cells, bright nestin-GFP+ cells and Mash1+ cells were stationary in the SVZ and rostral migratory stream (RMS). In our search for motile progenitor cells, we uncovered a population of motile bIII-tubulin+ neuroblasts that expressed low levels of epidermal growth factor receptor (EGFr). This was intriguing since EGFr drives proliferation in the SVZ and affects migration in other systems. Thus we examined the potential role of EGFr in modulating SVZ migration. Interestingly, EGFr low neuroblasts moved slower and in more tortuous patterns than EGFr-negative neuroblasts. We next questioned whether EGFr stimulation affects SVZ cell migration by imaging Gad65-GFP+ neuroblasts in the presence of transforming growth factor alpha (TGF-a), an EGFr-selective agonist. Indeed, acute exposure to TGF-a decreased the percentage of motile cells by approximately 40%

The role of inflammation in subventricular zone cancer

The adult subventricular zone (SVZ) stem cell niche has proven vital for discovering neurodevelopmental mechanisms and holds great potential in medicine for neurodegenerative diseases. Yet the SVZ holds a dark side - it can become tumorigenic. Glioblastomas can arise from the SVZ via cancer stem cells (CSCs). Glioblastoma and other brain cancers often have dismal prognoses since they are resistant to treatment. In this review we argue that the SVZ is susceptible to cancer because it contains stem cells, migratory progenitors and unusual inflammation. Theoretically, SVZ stem cells can convert to CSCs more readily than can postmitotic neural cells. Additionally, the robust long-distance migration of SVZ progenitors can be subverted upon tumorigenesis to an infiltrative phenotype. There is evidence that the SVZ, even in health, exhibits chronic low-grade cellular and molecular inflammation. Its inflammatory response to brain injuries and disease differs from that of other brain regions. We hypothesize that the SVZ inflammatory environment can predispose cells to novel mutations and exacerbate cancer phenotypes. This can be studied in animal models in which human mutations related to cancer are knocked into the SVZ to induce tumorigenesis and the CSC immune interactions that precede full-blown cancer. Importantly inflammation can be pharmacologically modulated providing an avenue to brain cancer management and treatment. The SVZ is accessible by virtue of its location surrounding the lateral ventricles and CSCs in the SVZ can be targeted with a variety of pharmacotherapies. Thus, the SVZ can yield aggressive tumors but can be targeted via several strategies

3,4,5-Tricaffeoylquinic acid induces adult neurogenesis and improves deficit of learning and memory in aging model senescence-accelerated prone 8 mice

Caffeoylquinic acid (CQA) is a natural polyphenol with evidence of antioxidant and neuroprotective effects and prevention of deficits in spatial learning and memory. We studied the cognitive-enhancing effect of 3,4,5-tricaffeoylquinic acid (TCQA) and explored its cellular and molecular mechanism in the senescence-accelerated mouse prone 8 (SAMP8) model of aging and Alzheimer’s disease as well as in human neural stem cells (hNSCs). Mice were fed with 5 mg/kg of TCQA for 30 days and were tested in the Morris water maze (MWM). Brain tissues were collected for immunohistochemical detection of bromodeoxyuridine (BrdU) to detect activated stem cells and newborn neurons. TCQA-treated SAMP8 exhibited significantly improved cognitive performance in MWM compared to water-treated SAMP8. TCQA-treated SAMP8 mice also had significantly higher numbers of BrdU+/glial fibrillary acidic protein (GFAP+) and BrdU+/Neuronal nuclei (NeuN+) cells in the dentate gyrus (DG) neurogenic niche compared with untreated SAMP8. In hNSCs, TCQA induced cell cycle arrest at G0/G1, actin cytoskeleton organization, chromatin remodeling, neuronal differentiation, and bone morphogenetic protein signaling. The neurogenesis promoting effect of TCQA in the DG of SAMP8 mice might explain the cognition-enhancing influence of TCQA observed in our study, and our hNSCs in aggregate suggest a therapeutic potential for TCQA in aging-associated diseases

3,4,5-Tricaffeoylquinic acid induces adult neurogenesis and improves deficit of learning and memory in aging model senescence-accelerated prone 8 mice

Caffeoylquinic acid (CQA) is a natural polyphenol with evidence of antioxidant and neuroprotective effects and prevention of deficits in spatial learning and memory. We studied the cognitive-enhancing effect of 3,4,5-tricaffeoylquinic acid (TCQA) and explored its cellular and molecular mechanism in the senescence-accelerated mouse prone 8 (SAMP8) model of aging and Alzheimer’s disease as well as in human neural stem cells (hNSCs). Mice were fed with 5 mg/kg of TCQA for 30 days and were tested in the Morris water maze (MWM). Brain tissues were collected for immunohistochemical detection of bromodeoxyuridine (BrdU) to detect activated stem cells and newborn neurons. TCQA-treated SAMP8 exhibited significantly improved cognitive performance in MWM compared to water-treated SAMP8. TCQA-treated SAMP8 mice also had significantly higher numbers of BrdU+/glial fibrillary acidic protein (GFAP+) and BrdU+/Neuronal nuclei (NeuN+) cells in the dentate gyrus (DG) neurogenic niche compared with untreated SAMP8. In hNSCs, TCQA induced cell cycle arrest at G0/G1, actin cytoskeleton organization, chromatin remodeling, neuronal differentiation, and bone morphogenetic protein signaling. The neurogenesis promoting effect of TCQA in the DG of SAMP8 mice might explain the cognition-enhancing influence of TCQA observed in our study, and our hNSCs in aggregate suggest a therapeutic potential for TCQA in aging-associated diseases

High-Resolution Patterned Cellular Constructs by Droplet-Based 3D Printing

AbstractBioprinting is an emerging technique for the fabrication of living tissues that allows cells to be arranged in predetermined three-dimensional (3D) architectures. However, to date, there are limited examples of bioprinted constructs containing multiple cell types patterned at high-resolution. Here we present a low-cost process that employs 3D printing of aqueous droplets containing mammalian cells to produce robust, patterned constructs in oil, which were reproducibly transferred to culture medium. Human embryonic kidney (HEK) cells and ovine mesenchymal stem cells (oMSCs) were printed at tissue-relevant densities (107 cells mL−1) and a high droplet resolution of 1 nL. High-resolution 3D geometries were printed with features of ≤200 μm; these included an arborised cell junction, a diagonal-plane junction and an osteochondral interface. The printed cells showed high viability (90% on average) and HEK cells within the printed structures were shown to proliferate under culture conditions. Significantly, a five-week tissue engineering study demonstrated that printed oMSCs could be differentiated down the chondrogenic lineage to generate cartilage-like structures containing type II collagen.</jats:p

Expression of <i>Idh1</i>^R132H in the murine subventricular zone stem cell niche recapitulates features of early gliomagenesis

Isocitrate dehydrogenase 1 mutations drive human gliomagenesis, probably through neomorphic enzyme activity that produces D-2-hydroxyglutarate. To model this disease, we conditionally expressed Idh1(R132H) in the subventricular zone (SVZ) of the adult mouse brain. The mice developed hydrocephalus and grossly dilated lateral ventricles, with accumulation of 2-hydroxyglutarate and reduced α-ketoglutarate. Stem and transit amplifying/progenitor cell populations were expanded, and proliferation increased. Cells expressing SVZ markers infiltrated surrounding brain regions. SVZ cells also gave rise to proliferative subventricular nodules. DNA methylation was globally increased, while hydroxymethylation was decreased. Mutant SVZ cells overexpressed Wnt, cell-cycle and stem cell genes, and shared an expression signature with human gliomas. Idh1(R132H) mutation in the major adult neurogenic stem cell niche causes a phenotype resembling gliomagenesis

Proliferation but Not Migration Is Associated with Blood Vessels during Development of the Rostral Migratory Stream

Blood vessels play a critical role in regulating neural stem cell proliferation and migration. We show here that blood vessels became progressively aligned in the direction of the rostral migratory stream (RMS) from embryonic day 14 to postnatal day 4. Dividing cells revealed by phosphohistone H3+ immunoreactivity were statistically closer to isolectin B4+ blood vessels than predicted by chance in the emerging RMS. The close proximity of blood vessels and H3+ cells was consistent regardless of the age of the RMS and was strikingly similar to the embryonic cerebral cortex. In contrast to the adult RMS, we found no evidence for preferential juxtaposition of migratory doublecortin-positive neuroblasts and vasculature in the neonatal RMS. Our work provides an important framework for understanding the precise mechanism behind regulation of proliferation

Subventricular zone cell migration: lessons from quantitative 2-photon microscopy

Neuroblasts born in the adult subventricular zone (SVZ) migrate long distances in the rostral migratory stream (RMS) to the olfactory bulbs where they integrate into circuitry as functional interneurons. As very little was known about the dynamic parameters of SVZ neuroblast migration, we used two-photon time-lapse microscopy to analyze migration in acute slices. This involved analyzing 3-dimensional stacks of images over time and uncovered several novel aspects of SVZ migration: chains remain stable, cells can be immotile for extensive periods, morphology does not necessarily correlate with motility, neuroblasts exhibit local exploratory motility, dorsoventral migration occurs throughout the striatal SVZ and neuroblasts turn at distinctive angles. We investigated these novel findings in the SVZ and RMS from the population to the single cell level. In this review we also discuss some technical considerations when setting up a two-photon microscopic imaging system. Throughout the review we identify several unsolved questions about SVZ neuroblast migration that might be addressed with current or emerging techniques