Caveolin-1 Autonomously Regulates Hippocampal Neurogenesis Via Mitochondrial Dynamics

The mechanisms underlying adult hippocampal neurogenesis (AHN) are not fully understood. AHN plays instrumental roles in learning and memory. Understanding the signals that regulate AHN has implications for brain function and therapy. Here we show that Caveolin-1 (Cav-1), a protein that is highly enriched in endothelial cells and the principal component of caveolae, autonomously regulates AHN. Conditional deletion of Cav-1 in adult neural progenitor cells (nestin +) led to increased neurogenesis and enhanced performance of mice in contextual discrimination. Proteomic analysis revealed that Cav-1 plays a role in mitochondrial pathways in neural progenitor cells. Importantly, Cav-1 was localized to the mitochondria in neural progenitor cells and modulated mitochondrial fission-fusion, a critical process in neurogenesis. These results suggest that Cav-1 is a novel regulator of AHN and underscore the impact of AHN on cognition.

NBP Cytoprotective Effects Promoting Neuronal Differentiation in BMSCs by Inhibiting the p65/Hes1 Pathway

Background

Bone marrow-derived mesenchymal stem cell (BMSC) transplantation has become an effective method for treating neurodegenerative diseases.

Objectives

This study investigated the effect of 3-N-butylphthalide (NBP) on the neuronal differentiation of BMSCs and its potential mechanism.

Methods

In this study, a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was performed to detect cell proliferation and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) staining was conducted to detect the apoptosis of BMSCs. Quantitative real-time polymerase chain reaction (RT-qPCR) and Western blot analysis were performed to detect the messenger RNA (mRNA) and protein expression levels, respectively. An enzyme-linked immunosorbent serologic assay assessed the levels of interleukin-1β, tumor necrosis factor-α, and cyclic adenosine monophosphate (cAMP). Moreover, a flow cytometry assay was used to detect the proportion of active β-tubulin III (TUJ-1) cells, and TUJ-1 expression was observed by immunofluorescence assay.

Results

The results showed that a low concentration of NBP promoted the proliferation and induction of BMSC neuronal differentiation while inhibiting apoptosis, the production of inflammatory factors, and p65 expression. Compared with differentiation induction alone, combined NBP treatment increased the levels of nestin, neuron-specific enolase (NSE), TUJ-1, and microtubule-associated protein 2 (MAP2) protein, as well as the ratio of TUJ-1-positive cells and cAMP expression. Furthermore, p65 overexpression weakened the effect of NBP, and the overexpression of hairy and enhancer of split homolog-1 (HES1) reversed the effect of NBP in the induction of BMSC neuronal differentiation in vitro.

Conclusions

We confirmed that NBP exhibited potential therapeutic properties in the stem cell transplantation treatment of neurodegenerative diseases by protecting cells and promoting BMSC neuronal differentiation by inhibiting the p65/HES 1 pathway.

A MYT1L syndrome mouse model recapitulates patient phenotypes and reveals altered brain development due to disrupted neuronal maturation

Human genetics have defined a new neurodevelopmental syndrome caused by loss-of-function mutations in MYT1L, a transcription factor known for enabling fibroblast-to-neuron conversions. However, how MYT1L mutation causes intellectual disability, autism, ADHD, obesity, and brain anomalies is unknown. Here, we developed a Myt1l haploinsufficient mouse model that develops obesity, white-matter thinning, and microcephaly, mimicking common clinical phenotypes. During brain development we discovered disrupted gene expression, mediated in part by loss of Myt1l gene-target activation, and identified precocious neuronal differentiation as the mechanism for microcephaly. In contrast, in adults we discovered that mutation results in failure of transcriptional and chromatin maturation, echoed in disruptions in baseline physiological properties of neurons. Myt1l haploinsufficiency also results in behavioral anomalies, including hyperactivity, muscle weakness, and social alterations, with more severe phenotypes in males. Overall, our findings provide insight into the mechanistic underpinnings of this disorder and enable future preclinical studies.

Mouse Enteric Neuronal Cell Culture

In the enteric nervous system, there exist a huge number of local intrinsic neurons, which control the gastrointestinal functions. Culture of enteric neurons provides a good model system for physiological, electrophysiological, and pharmacological studies. Here, we describe two methods to obtain sufficient enteric neurons from mouse myenteric plexuses by directly culturing primary neurons or inducing neuronal differentiation of enteric neural stem/progenitor cells.

Inducible TDG knockout models to study epigenetic regulation

Mechanistic and functional studies by gene disruption or editing approaches often suffer from confounding effects like compensatory cellular adaptations generated by clonal selection. These issues become particularly relevant when studying factors directly involved in genetic or epigenetic maintenance. To provide a genetic tool for functional and mechanistic investigation of DNA-repair mediated active DNA demethylation, we generated experimental models in mice and murine embryonic stem cells (ESCs) based on a minigene of the thymine-DNA glycosylase (TDG). The loxP-flanked miniTdg is rapidly and reliably excised in mice and ESCs by tamoxifen-induced Cre activation, depleting TDG to undetectable levels within 24 hours. We describe the functionality of the engineered miniTdg in mouse and ESCs (TDGiKO ESCs) and validate the pluripotency and differentiation potential of TDGiKO ESCs as well as the phenotype of induced TDG depletion. The controlled and rapid depletion of TDG allows for a precise manipulation at any point in time of multistep experimental procedures as presented here for neuronal differentiation in vitro. Thus, we provide a tested and well-controlled genetic tool for the functional and mechanistic investigation of TDG in active DNA (de)methylation and/or DNA repair with minimal interference from adaptive effects and clonal selection.

Inducible TDG knockout models to study epigenetic regulation

Mechanistic and functional studies by gene disruption or editing approaches often suffer from confounding effects like compensatory cellular adaptations generated by clonal selection. These issues become particularly relevant when studying factors directly involved in genetic or epigenetic maintenance. To provide a genetic tool for functional and mechanistic investigation of DNA-repair mediated active DNA demethylation, we generated experimental models in mice and murine embryonic stem cells (ESCs) based on a minigene of the thymine-DNA glycosylase (TDG). The loxP-flanked miniTdg is rapidly and reliably excised in mice and ESCs by tamoxifen-induced Cre activation, depleting TDG to undetectable levels within 24 hours. We describe the functionality of the engineered miniTdg in mouse and ESCs (TDGiKO ESCs) and validate the pluripotency and differentiation potential of TDGiKO ESCs as well as the phenotype of induced TDG depletion. The controlled and rapid depletion of TDG allows for a precise manipulation at any point in time of multistep experimental procedures as presented here for neuronal differentiation in vitro. Thus, we provide a tested and well-controlled genetic tool for the functional and mechanistic investigation of TDG in active DNA (de)methylation and/or DNA repair with minimal interference from adaptive effects and clonal selection.

The Effects of Embryonic Cerebrospinal Fluid on The Viability and Neuronal Differentiation of Adipose Tissue-Derived Stem Cells in Wistar Rats

Objective

The embryonic cerebrospinal fluid (e-CSF) contains various growth factors and morphogens. Recent studies showed that e-CSF plays significant roles in embryonic brain development. Adipose tissue-derived stem cells (ADSCs) have a mesodermal origin that can be differentiated into mesodermal and ectodermal lineages. This study aimed to evaluate the effects of e-CSF on the proliferation, viability, and neural differentiation of ADSCs in rats.

Materials and Methods

In this experimental study, adipose tissue was dissected out from the inguinal region of adult male rats. Then, ADSCs were isolated by enzymatic digestion from adipose tissues and mesenchymal cells were confirmed using the flow cytometry analysis that measured the cell surface markers including CD90, CD44, CD73, CD105, CD34, CD45, and CD11b. The multi-potential characteristics of ADSCs were assessed by osteogenic and adipogenic potentials of these cells. Under suitable in vitro conditions, ADSCs were cultured in DMEM supplemented with and without additional 10% e-CSF. These fluids were collected from Wistar rats at the E17, E18, and E19 gestational ages. Cellular proliferation and viability were determined using the MTT assay. Immunocytochemistry was used to study the expression of β-III tubulin in ADSCs. The neurite outgrowth of cultured cells was assessed using the ImageJ software.

Result

The results of the present study demonstrated that the viability of ADSCs in cell culture conditioned with E17 and E18 e-CSF were significantly increased in comparison with controls. Cultured cells treated with e-CSF from E18 and E19 established neuronal-like cells bearing long process, whereas no process was observed in the control groups or cultured cells treated with E17 e-CSF.

Conclusion

This study showed that e-CSF has the ability to induce neuronal differentiation and viability in ADSCs. Our data support a significant role of e-CSF as a therapeutic strategy for the treatment of neurodegenerative diseases.

Hypothesis: A Challenge of Overexpression Zfp521 in Neural Tendency of Derived Dental Pulp Stem Cells

Neurodegenerative diseases have now become a major challenge, especially in aged societies. Most of the traditional strategies used for treatment of these diseases are untargeted and have little efficiency. Developments in stem cell investigations have given much attention to cell therapy as an alternative concept in the regeneration of neural tissues. Dental pulp stem cells (DPSCs) can be readily obtained by noninvasive procedures and have been shown to possess properties similar to well-known mesenchymal stem cells. Furthermore, based on their neural crest origin, DPSCs are considered to have a good potential to differentiate into neural cells. Zfp521 is a transcription factor that regulates expression of many genes, including ones involved in the neural differentiation process. Therefor based on neural crest origin of the cell and high expression of neural progenitor markers, we speculate that sole overexpression of Zfp521 protein can facilitate differentiation of dental stem cells to neural cells and researchers may find these cells suitable for therapeutic treatment of neurodegenerative diseases.

Identification of a dithiol-disulfide switch in collapsin response mediator protein 2 (CRMP2) that is toggled in a model of neuronal differentiation

Vertebrate-specific glutaredoxin 2 (Grx2) is expressed in at least two isoforms, mitochondrial Grx2a and cytosolic Grx2c. We have previously shown that cytosolic Grx2 is essential for embryonic development of the brain. In particular, we identified collapsin response mediator protein 2 (CRMP2/DPYSL2), a mediator of the semaphorin-plexin signaling pathway, as redox-regulated target of Grx2c and demonstrated that this regulation is required for normal axonal outgrowth. In this study, we demonstrate the molecular mechanism of this regulation, a specific and reversible intermolecular Cys-504-Cys-504 dithiol-disulfide switch in homotetrameric CRMP2. This switch determines two conformations of the quaternary CRMP2 complex that controls axonal outgrowth and thus neuronal development.

Fate of transplanted bone marrow derived mesenchymal stem cells following spinal cord injury in rats by transplantation routes

This research was performed to investigate the differences of the transplanted cells' survival and differentiation, and its efficacy according to the delivery routes following spinal cord injury. Allogenic mesenchymal stem cells (MSCs) were transplanted intravenously (IV group) or intralesionally (IL group) at post-injury 1 day in rats. Behavioral improvement, engraftment and differentiation of the transplanted cells and the expression of neurotrophic factors of the transplanted groups were analyzed and compared with those of the control group. At 6 weeks post-injury, the mean BBB motor scales in the control, IV and IL groups were 6.5 ± 1.8, 11.1 ± 2.1, and 8.5 ± 2.8, respectively. Regardless of the delivery route, the MSCs transplantation following spinal cord injuries presented better behavioral improvement. The differentiations of the engrafted cells were different according to the delivery routes. The engrafted cells predominantly differentiated into astrocytes in the IV group and on the other hand, engrafted cells of the IL group demonstrated relatively even neural and glial differentiation. The expressions of neuronal growth factor were significantly higher in the IL group (mean relative optical density, 2.4 ± 0.15) than those in the control (2.16 ± 0.04) or IV group (1.7 ± 0.23). Transplantation of MSCs in the early stage of spinal cord injury gives a significant clinical improvement. However, the fate of the transplanted MSCs and expression of neuronal growth factors are different along the transplantation route.