Injured inflammatory environment overrides the TET2 shaped epigenetic landscape of pluripotent stem cell derived human neural stem cells.

Spinal cord injury creates an inflammatory microenvironment that regulates the capacity of transplanted human Neural Stem Cells (hNSC) to migrate, differentiate, and repair injury. Despite similarities in gene expression and markers detected by immunostaining, hNSC populations exhibit heterogeneous therapeutic potential. This heterogeneity derives in part from the epigenetic landscape in the hNSC genome, specifically methylation (5mC) and hydroxymethylation (5hmC) state, which may affect the response of transplanted hNSC in the injury microenvironment and thereby modulate repair capacity.

Individual longitudinal changes in DNA-methylome identify signatures of early-life adversity and correlate with later outcome.

Adverse early-life experiences (ELA) affect a majority of the world's children. Whereas the enduring impact of ELA on cognitive and emotional health is established, there are no tools to predict vulnerability to ELA consequences in an individual child. Epigenetic markers including peripheral-cell DNA-methylation profiles may encode ELA and provide predictive outcome markers, yet the interindividual variance of the human genome and rapid changes in DNA methylation in childhood pose significant challenges.

Inhibition of Neuron-Restrictive Silencing Factor (REST/NRSF) Chromatin Binding Attenuates Epileptogenesis.

The mechanisms by which brain insults lead to subsequent epilepsy remain unclear. Insults including trauma, stroke, infections, and long seizures (status epilepticus, SE) increase the nuclear expression and chromatin binding of the neuron-restrictive silencing factor/RE-1 silencing transcription factor (NRSF/REST). REST/NRSF orchestrates major disruption of the expression of key neuronal genes, including ion channels and neurotransmitter receptors, potentially contributing to epileptogenesis.

Within-subject changes in methylome profile identify individual signatures of early-life adversity, with a potential to predict neuropsychiatric outcome.

Background: Adverse early-life experiences (ELA), including poverty, trauma and neglect, affect a majority of the world's children. Whereas the impact of ELA on cognitive and emotional health throughout the lifespan is well-established, it is not clear how distinct types of ELA influence child development, and there are no tools to predict for an individual child their vulnerability or resilience to the consequences of ELAs. Epigenetic markers including DNA-methylation profiles of peripheral cells may encode ELA and provide a predictive outcome marker.

Single-Cell Transcriptional Changes in Hypothalamic Corticotropin-Releasing Factor-Expressing Neurons After Early-Life Adversity Inform Enduring Alterations in Vulnerabilities to Stress.

Background: Mental health and vulnerabilities to neuropsychiatric disorders involve the interplay of genes and environment, particularly during sensitive developmental periods. Early-life adversity (ELA) and stress promote vulnerabilities to stress-related affective disorders, yet it is unknown how transient ELA dictates lifelong neuroendocrine and behavioral reactions to stress. The population of hypothalamic corticotropin-releasing factor (CRF)-expressing neurons that regulate stress responses is a promising candidate to mediate the long-lasting influences of ELA on stress-related behavioral and hormonal responses via enduring transcriptional and epigenetic mechanisms.

Unexpected Transcriptional Programs Contribute to Hippocampal Memory Deficits and Neuronal Stunting after Early-Life Adversity.

Early-life adversity (ELA) is associated with lifelong memory deficits, yet the responsible mechanisms remain unclear. We impose ELA by rearing rat pups in simulated poverty, assess hippocampal memory, and probe changes in gene expression, their transcriptional regulation, and the consequent changes in hippocampal neuronal structure. ELA rats have poor hippocampal memory and stunted hippocampal pyramidal neurons associated with ~140 differentially expressed genes.

Intra-individual methylomics detects the impact of early-life adversity.

Genetic and environmental factors interact during sensitive periods early in life to influence mental health and disease via epigenetic processes such as DNA methylation. However, it is not known if DNA methylation changes outside the brain provide an "epigenetic signature" of early-life experiences. Here, we used a novel intra-individual approach by testing DNA methylation from buccal cells of individual rats before and immediately after exposure to one week of typical or adverse life experience.

Increasing Human Neural Stem Cell Transplantation Dose Alters Oligodendroglial and Neuronal Differentiation after Spinal Cord Injury.

Multipotent human central nervous system-derived neural stem cells transplanted at doses ranging from 10,000 (low) to 500,000 (very high) cells differentiated predominantly into the oligodendroglial lineage. However, while the number of engrafted cells increased linearly in relationship to increasing dose, the proportion of oligodendrocytic cells declined. Increasing dose resulted in a plateau of engraftment, enhanced neuronal differentiation, and increased distal migration caudal to the transplantation sites.

CD133-enriched Xeno-Free human embryonic-derived neural stem cells expand rapidly in culture and do not form teratomas in immunodeficient mice.

Common methods for the generation of human embryonic-derived neural stem cells (hNSCs) result in cells with potentially compromised safety profiles due to maintenance of cells in conditions containing non-human proteins (e.g. in bovine serum or on mouse fibroblast feeders).

Induction of early neural precursors and derivation of tripotent neural stem cells from human pluripotent stem cells under xeno-free conditions.

Human embryonic stem cells (hESC) and induced pluripotent stem cells (hiPSC) can differentiate into many cell types and are important for regenerative medicine; however, further work is needed to reliably differentiate hESC and hiPSC into neural-restricted multipotent derivatives or specialized cell types under conditions that are free from animal products. Toward this goal, we tested the transition of hESC and hiPSC lines onto xeno-free (XF) / feeder-free conditions and evaluated XF substrate preference, pluripotency, and karyotype. Critically, XF transitioned H9 hESC, Shef4 hESC, and iPS6-9 retained pluripotency (Oct-4 and NANOG), proliferation (MKI67 and PCNA), and normal karyotype.

Immunosuppressants affect human neural stem cells in vitro but not in an in vivo model of spinal cord injury.

Clinical immunosuppression protocols use calcineurin inhibitors, such as cyclosporine A (CsA) or tacrolimus (FK506), or mammalian target of rapamycin (mTOR) inhibitors, such as sirolimus (rapamycin). These compounds alter immunophilin ligand signaling pathways, which are known to interact downstream with mediators for human neural stem cell (hNSC) differentiation and proliferation, suggesting that immunosuppressants may directly alter hNSC properties. We investigated whether immunosuppressants can exert direct effects on the differentiation, proliferation, survival, and migration of human central nervous system-derived stem cells propagated as neurospheres (hCNS-SCns) in vitro and in an in vivo model of spinal cord injury.

Egg and sperm recognition systems during fertilization.

Fertilization is a programmed process that has many molecules and sequential events amenable to study. The biochemistry of fertilization has identified cellular and acellular components fundamental to the interactions between sperm and egg. Recent studies highlight the molecular details of the species-specificity of fertilization that involve protein-protein and protein-carbohydrate interactions.

The species-specific egg receptor for sea urchin sperm adhesion is EBR1,a novel ADAMTS protein.

Species-specific adhesion of sperm to the egg during sea urchin fertilization involves the interaction of the sperm adhesive protein,bindin, and a complementary receptor on the egg surface,and serves to restrict the gene pool to individuals of the same species. We used PCR representation difference analysis to clone the species-specific egg receptor for bindin, EBR1, from Strongylocentrotus franciscanus (Sf) and S. purpuratus (Sp).