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imilar to mesenchymal stem cells after one week in culture. Thesexpanded cells were further characterized by FACS analysis withSC specific markers such as CD 29 (88.5%) and CD 105 (87%) indi-

ating their MSC lineage. These primary UCB-MSCs were exposedo neuronal differentiation condition and found that they coulde very easily differentiated into neurons whereas the RCB 2080UCB-MSC cell line and other MSCs isolated from UCB had to bexposed to a series of growth factors to attain neurogenic poten-ial. We also found a consistent expression of pluripotent markersuch as Oct4, Nanog, Sox2, ABCG2 and neuro-ectodermal marker,estin in freshly isolated as well as proliferating MSCs indicating

he presence of neural stem cell like properties within the popula-ion of MSCs. The neurogenic potential of different UCB-MSCs alsoaries from each other. Therefore, these results indicate that it is themall population of cells with inherent neurogenic potential that isifferentiating into neurons in addition to trans-differentiation ofSCs. From these preliminary results we conclude that there existsself-renewing neural stem cell like populations in umbilical cordlood which needs to be further characterized.

Supported by funding from Dept. of Biotechnology & ICMR, Govt. ofndia.

oi:10.1016/j.ijdevneu.2012.03.260

ate specific differentiation of neural stem cells maintained byifferential Hes-1 expression

.B. Dhanesh, C. Subashini, T.S. Divya, Jackson James ∗

Neuro-stem Cell Biology Lab, Neurobiology Division, Rajiv Gandhi Cen-re for Biotechnology, Trivandrum, Kerala, India

Notch signaling, one of the most important signaling pathwaysuring embryogenesis, plays a key role in neural progenitor main-enance, proliferation and differentiation during mammalian CNSevelopment. Even though both Hes-1 and Hes-5 are the princi-al target genes of canonical Notch signaling, Hes-1 is not alwaysnder the strict control of Notch. It was shown that indeed neu-al progenitors comprise both Notch dependent and independentopulations and the Notch independent population is maintainedhrough the activation of Hes-1 by basic Fibroblast Growth FactorbFGF), and mediated through JNK-Activating transcription factor

(ATF2) signaling. Existence of such a subset of neural progeni-ors with Notch independent Hes-1 expression will have a lot ofignificance since these cells do not depend on interactions fromeighboring cells through classical Notch activation. The consistentxpression of Hes-1 can lead to exponential expansion of neuralrogenitors that are required during development. Based on thesendings, we further characterized the CBF1 independent progen-

tors having differential Hes-1 gene expression with respect to itsroliferation and fate specific differentiation in vitro.

Acknowledgement: Supported by grants from DBT & CSIR, Govt.f India.

oi:10.1016/j.ijdevneu.2012.03.261

dentification of microRNA involved in development andifferentiation of Retinal Ganglion Cells

.T. Abdul Rasheed, Jackson James ∗

Neuro-Stem Cell Biology Laboratory, Neurobiology Division, Rajivandhi Centre for Biotechnology, Trivandrum, Kerala, India

Retinal Ganglion Cell (RGC) is a highly specialized neuron in theetina with a distinct profile of genes that determines their devel-pment, structurally and functionally. Information regarding their

uroscience 30 (2012) 640–671 651

molecular composition and characteristics remains incomplete.Recent studies focus on unveiling the detailed molecular mech-anism underlying RGC genesis and development. UnderstandingRGC fate specification and development may help in designingstrategies to prevent or treat loss of vision such as those in retinaldegenerative diseases like glaucoma. Studies suggest that miR-NAs may play a vital role in the regulation of eye development.Identification and characterization of RGC specific miRNAs could beimportant in understanding the molecular and cellular processesinvolved in the differentiation of RGCs and for developing bettertherapeutic strategies. Shedding light into these complex molecu-lar mechanisms, which may involve microRNAs would be relevantin understanding the development and differentiation of RGCs. Thepresent study includes predicting and validating those miRNAs thatmay interact with RGC-specific regulators including Brn3b, Ath5,Wt1, etc. From the software prediction, Mir374 was found to havebinding sites in 3′UTRs of Brn3b and Ath5 while mir-669f, 323-3pwould bind to 3′UTRs of Brn3b and Wt1. The interactions of themiRNAs to their respective UTRs were validated in HEK293T cells,RGC-5 cells and mice retinal primary cultures by cloning of the pre-dicted miRNAs and their target 3′UTR regions to specific vectors.Preliminary data suggests that miR374, 669f and 23a can bind toBrn3b 3′UTR and may regulate the differentiation of RGCs.

Supported by grants from DBT & CSIR, Govt. of India.

doi:10.1016/j.ijdevneu.2012.03.262

Differential roles for ionic and metabolic glucosensing in a min-imal model of VMH glucose-excited neurons

Neelima Sharma a,∗, Pranay Goel b, Arthur Sherman c

a NCBS, Bangalore, Indiab IISER, Pune, Indiac N.I.H.-N.I.D.D.K.-L.B.M, Bethesda, USA

Ventromedial hypothalamic (VMH) neurons show excitatory orinhibitory electrical response towards changing extracellular glu-cose concentration. Glucose excitatory neurons (GE) increase theirfiring rate with increasing glucose and by far the most popularmodel of GE neurons is inspired by the consensus model of thepancreatic beta-cell. An alternative mechanism of glucose sensingis believed to involve an ion channel like Sodium Glucose con-transporter (SGLT) that directly senses glucose. Most efforts atdiscriminating two mechanisms have been indirect.

We construct two minimal mathematical models of GE neu-rons: one in which the mechanism of glucose excitation isvia glucose-induced changes in the ATP–ADP ratio, called the‘metabolic model’; another in which SGLT channels on the mem-brane monitors extracellular glucose, termed the ‘ionic model’.The mathematical model assigns two separate roles to ionic andmetabolic mechanism and these results can be used to designexperiments to reveal the actual mechanism of glucose sensing.According to the model, cell dominated by an ionic mechanismshould saturate in its glucose response for lower values of glucose ascompared to a cell involving glycolytic mechanism. Another markerfor distinguishing ionic and metabolic models is the timescale onwhich they respond to glucose pulses. Ionic sensing mechanism isextremely responsive to changes in glucose concentrations withimmediate attainment of asymptotic state while metabolic modelfeatures a time lag.

We have also demonstrated that GE cells might sense glucosevia both ionic and metabolic mechanisms, i.e. both pathways are

included in the same cell. Such hybrid models seem to includethe favorable characteristics of both ionic and metabolic models:they are able to sense changes in glucose concentrations relatively