Ephrin-B3 decreases the survival of adult rat spinal cord-derived neural stem/progenitor cells in vitro and after transplantation into the injured rat spinal cord

Blood vessels guide Schwann cell migration in the adult demyelinated CNS through Eph/ephrin signaling

Schwann cells (SC) enter the central nervous system (CNS) in pathophysiological conditions. However, how SC invade the CNS to remyelinate central axons remains undetermined. We studied SC migratory behavior ex vivo and in vivo after exogenous transplantation in the demyelinated spinal cord. The data highlight for the first time that SC migrate preferentially along blood vessels in perivascular extracellular matrix (ECM), avoiding CNS myelin. We demonstrate in vitro and in vivo that this migration route occurs by virtue of a dual mode of action of Eph/ephrin signaling. Indeed, EphrinB3, enriched in myelin, interacts with SC Eph receptors, to drive SC away from CNS myelin, and triggers their preferential adhesion to ECM components, such as fibronectin via integrinβ1 interactions. This complex interplay enhances SC migration along the blood vessel network and together with lesion-induced vascular remodeling facilitates their timely invasion of the lesion site. These novel findings elucidate the mechanism by which SC invade and contribute to spinal cord repair.

Electroacupuncture at Baihui (DU20) acupoint up-regulates mRNA expression of NeuroD molecules in the brains of newborn rats suffering in utero fetal distress

NeuroD plays a key regulatory effect on differentiation of neural stem cells into mature neurons in the brain. Thus, we assumed that electroacupuncture at Baihui (DU20) acupoint in newborn rats exposed to in utero fetal distress would influence expression of NeuroD. Electroacupuncture at Baihui was performed for 20 minutes on 3-day-old (Day 3) newborn Sprague-Dawley rats exposed to in utero fetal distress; electroacupuncture parameters consisted of sparse and dense waves at a frequency of 2–10 Hz. Real-time fluorescent quantitative PCR results demonstrated that mRNA expression of NeuroD, a molecule that indicates NeuroD, increased with prolonged time in brains of newborn rats, and peaked on Day 22. The level of mRNA expression was similar between Day 16 and Day 35. These findings suggest that electro acupuncture at Baihui acupoint could effectively increase mRNA expression of molecules involved in NeuroD in the brains of newborn rats exposed to in utero fetal distress.

Over-expression of hNGF in adult human olfactory bulb neural stem cells promotes cell growth and oligodendrocytic differentiation

The adult human olfactory bulb neural stem/progenitor cells (OBNC/PC) are promising candidate for cell-based therapy for traumatic and neurodegenerative insults. Exogenous application of NGF was suggested as a promising therapeutic strategy for traumatic and neurodegenerative diseases, however effective delivery of NGF into the CNS parenchyma is still challenging due mainly to its limited ability to cross the blood-brain barrier, and intolerable side effects if administered into the brain ventricular system. An effective method to ensure delivery of NGF into the parenchyma of CNS is the genetic modification of NSC to overexpress NGF gene. Overexpression of NGF in adult human OBNSC is expected to alter their proliferation and differentiation nature, and thus might enhance their therapeutic potential. In this study, we genetically modified adult human OBNS/PC to overexpress human NGF (hNGF) and green fluorescent protein (GFP) genes to provide insight about the effects of hNGF and GFP genes overexpression in adult human OBNS/PC on their in vitro multipotentiality using DNA microarray, immunophenotyping, and Western blot (WB) protocols. Our analysis revealed that OBNS/PC-GFP and OBNS/PC-GFP-hNGF differentiation is a multifaceted process involving changes in major biological processes as reflected in alteration of the gene expression levels of crucial markers such as cell cycle and survival markers, stemness markers, and differentiation markers. The differentiation of both cell classes was also associated with modulations of key signaling pathways such MAPK signaling pathway, ErbB signaling pathway, and neuroactive ligand-receptor interaction pathway for OBNS/PC-GFP, and axon guidance, calcium channel, voltage-dependent, gamma subunit 7 for OBNS/PC-GFP-hNGF as revealed by GO and KEGG. Differentiated OBNS/PC-GFP-hNGF displayed extensively branched cytoplasmic processes, a significant faster growth rate and up modulated the expression of oligodendroglia precursor cells markers (PDGFRα, NG2 and CNPase) respect to OBNS/PC-GFP counterparts. These findings suggest an enhanced proliferation and oligodendrocytic differentiation potential for OBNS/PC-GFP-hNGF as compared to OBNS/PC-GFP.