Retinoic Acid and Human Olfactory Ensheathing Cells Cooperate to Promote Neural Induction From Human Bone Marrow Stromal Stem Cells

The generation of induced neuronal cells from human bone marrow stromal stem cells (hBMSCs) provides new avenues for basic research and potential transplantation therapies for nerve injury and neurological disorders. However, clinical application must seriously consider the risk of tumor formation by hBMSCs, neural differentiation efficiency and biofunctions resembling neurons. Here, we co-cultured hBMSCs exposed to retinoic acid (RA) with human olfactory ensheathing cells (hOECs) to stimulate its differentiation into neural cells, and found that hBMSCs following 1 and 2 weeks of stimulation promptly lost their immunophenotypical profiles, and gradually acquired neural cell characteristics, as shown by a remarkable up-regulation of expression of neural-specific markers (Tuj-1, GFAP and Galc) and down-regulation of typical hBMSCs markers (CD44 and CD90), as well as a rapid morphological change. Concomitantly, in addition to a drastic decrease in the number of BrdU incorporated cells, there was a more elevated synapse formation (a hallmark for functional neurons) in the differentiated hBMSCs. Compared with OECs alone, this specific combination of RA and hOECs was significantly potentiated neuronal differentiation of hBMSCs. The results suggest that RA can enhance and orchestrate hOECs to neural differentiation of hBMSCs. Therefore, these findings may provide an alternative strategy for the repair of traumatic nerve injury and neurological diseases with application of the optimal combination of RA and OECs for neuronal differentiation of hBMSCs.     

Lentivirus carrying the Atoh1 gene infects normal rat cochlea

Lentivirus carrying the Atoh1 gene can infect Corti’s organ and express a hair-like cell surface marker in the supporting cell area. However, expression of the gene carried by adenovirus is instantaneous, which undoubtedly limits its clinical application. Lentivirus acts as a carrier that can stably and continuously express genes. In this study, the cochlear structure and hearing level were not affected, and Atoh1 gene carried by lentivirus promoted the production of hair-like cells in the cochlear supporting cell area. This led to expression of the hair-like cell surface marker myosin 7a 30 days after lentivirus carrying Atoh1 was microinjected into the cochlear round window of rats.     

Ginkgo biloba leaf extract improves the cognitive abilities of rats with D-galactose induced dementia

Standardized Ginkgo biloba leaf extract has been used in clinical trials for its beneficial effects on brain functions,particularly in dementia.Substantial experimental evidences indicated that Ginkgo biloba leaf extract (EGB) protected neuronal cells from a variety of insults.We investigated the effect of EGB on cognitive ability and protein kinase B (PKB) activity in hippocampal neuronal cells of dementia model rats.Rats received an intraperitoneal injection of D-galactose to induce dementia.Forty-eight Spraque-Dawley rats were randomly divided into six groups,including the control group,D-galactose group (Gal),low-dose EGB group (EGB-L),mid-dose EGB group (EGB-M),high-dose EGB group (EGB-H) and treatment group.The EGB-L,EGB-M and EGB-H groups were administered with EGB and D-galactose simultaneously.Y-maze,cresyl violet staining,TUNEL assays and immunohistochemistry staining were performed to detect learning and memory abilities,morphological changes in the hippocampus,neuronal apoptosis and the expressing level of phospho-PKB,respectively.Rats in the Gal group showed decreased abilities of learning and memory,and hippocampal pyramidal cell layer was damaged,while EGB administration improved learning and memory abilities.The Gal group exhibited many stained,condensed nuclei and micronuclei,either isolated or within the cytoplasm of cells (39.5±1.4).Apoptotic cells decreased in the groups of EGB-L (35.9±0.9),EGB-M (16.8±1.0) and EGB-H (10.1±0.8),and there were statistical significances compared with the Gal group.Immunoreactivity of phospho-PKB was localized diffusely throughout the cytosol of cells in all groups,while the immunoreactivity of the Gal group was weak.EGB significantly attenuated learning and memory impairment in a dose-dependent manner,while it could decrease the nmber of TUNEL-positive cells,and increase the activity of PKB.Our results demonstrated that EGB attenuated memory impairment and cell apoptosis in galactose-induced dementia model rats by activating PKB.     

Generation of human neutralizing monoclonal antibodies against the 2009 pandemic H1N1 virus from peripheral blood memory B lymphocytes

The 2009 H1N1 influenza pandemic demonstrated the significance of a global health threat to human beings. Although pandemic H1N1 vaccines have been rapidly developed, passive serotherapy may offer superior immediate protection against infections in children, the elderly and immune-compromised patients during an influenza pandemic. Here, we applied a novel strategy based on Epstein–Barr virus (EBV)-immortalized peripheral blood memory B cells to screen high viral neutralizing monoclonal antibodies (MAbs) from individuals vaccinated with the 2009 pandemic H1N1 vaccine PANFLU.1. Through a massive screen of 13 090 immortalized memory B-cell clones from three selected vaccinees, seven MAbs were identified with both high viral neutralizing capacities and hemagglutination inhibition (HAI) activities against the 2009 pandemic H1N1 viruses. These MAbs may have important clinical implications for passive serotherapy treatments of infected patients with severe respiratory syndrome, especially children, the elderly and immunodeficient individuals. Our successful strategy for generating high-affinity MAbs from EBV-immortalized peripheral blood memory B cells may also be applicable to other infectious or autoimmune diseases.     

Role of Akt signaling pathway in delayed cerebral vasospasm after subarachnoid hemorrhage in rats

Background

Akt plays an important role in cell survival, proliferation, apoptosis and other activities. It also has been involved in maintaining smooth muscle cell contraction phenotypes in vitro and in vivo. Recent studies have focused on the inhibition of Akt in acute vasospasm and neuronal apoptosis after subarachnoid hemorrhage (SAH). However, its role in delayed cerebral vasospasm (DCVS) has not been reported.

Methods

In this study, using a “two-hemorrhage” rat model of SAH, we examined the expression of p-Akt and the formation of vasospasm in the basilar arteries. To investigate the possible role of Akt in phenotypic switching, we performed immunohistochemical staining to examine expressions of SMα-actin and proliferating cell nuclear antigen (PCNA), markers of smooth muscle phenotypic switching.

Results

We found that the basilar arteries exhibited vasospasm after SAH and that vasospasm became most severe on day 7 after SAH. Elevated protein expression of p-Akt was detected 4 days after SAH induction, peaked on day 7, and recovered on day 21, which was in a parallel time course to the development of DCVS. Moreover, results of immunohistochemical staining revealed enhanced expression of PCNA but gradual reduction in expression of SMα-actin from day 1 to day 7 after SAH; then, the expressions of PCNA and SMα-actin gradually recovered until day 21.

Conclusions

These results support a novel mechanism in which the Akt signaling pathway plays an important role in the proliferation of smooth muscle cells (SMCs) rather than inducing phenotype switching in basilar arteries, which promotes the development of DCVS after SAH.