Congress Abstracts - Society for Developmental Biology

NPCs blunted proliferation in the SGZ. Using functional genomics, we identified potential downstream target genes of Sox11.
Conclusions: Taken together, our work provides evidence that Sox11 is required for both embryonic and adult neurogenesis.
Program/Abstract # 544
Expression of histamine receptors during midbrain development of rat embryos
Vargas Romero, Fernanda; Escobedo Avila, Itzel; Velasco Velazquez, Ivan (UNAM, Mexico)
During formation of the midbrain (Mb) one key event is differentiation of neurons, which takes place between embryonic days 12 to
16 (E12-E16). Histamine (HA) is one of the first neurotransmitters synthesized in the developing brain. Particularly, in the Mb region,
the highest concentration of HA is found at E14-16, which coincides with neurogenesis in this cerebral region. Our group has shown
that HA induces neuronal differentiation of cortical neural progenitors into FOXP2 neurons, an effect that is due to activation of HA
receptor type 1 (HR 1 ). In the central nervous system, HA acts through activation of G-coupled protein receptors (HR 1 -HR 3 ).
Hybridization studies have shown that these HA receptors are expressed in the developing brain. However, the identity of the cells that
express such receptors is unknown. In this work, we aimed to characterize the expression HR 1 and HR 2 during de first stages of Mb
neurogenesis. We found that expression of HR 1 is homogeneous at E12 on Nestin-positive neural progenitors, and as development
proceeds this expression is limited to the ventral-most region of the Mb. No co-expression of this receptor with Tuj1+ differentiated
neurons was found. On the other hand, although the expression of HR 2 at E12 is found throughout the Mb in Nestin+ cells, as
development proceeds, HR 2 is just expressed on the dorsal Mb. These results constitute a starting point to explore HA actions during
Mb formation.
Program/Abstract # 545
Characterization of Medulloblastoma and Glioblastoma Variants with Molecular Markers of Neural Stem Cells
Toledo Hernández, Diana; Ponce Regalado, María Dolores; Lira Díaz, Eduardo; Stephenson Gussinyé, Tania; Esquivel Estudillo,
Joel; Jaimes Jiménez, Venus Deyanira; Tenorio Mina, Andrea (UNAM-Cuernavaca, Mexico); Rembao Bojórquez, Jesús Daniel
(UNAM, Mexico); Ocampo Roosens, Valeria; Ontiveros Nevares, Patricia (UNAM-Cuernavaca, Mexico); Pérez González, Oscar A.
(UNAM, Mexico); Galvez Molina, Yolanda; Contreras Florencia, Armando; Santa Olalla Tapia, Jesús (UNAM-Cuernavaca, Mexico)
Medulloblastoma (MB) and Glioblastoma (GB) are the most aggressive and common of the Central Nervous System (CNS) tumors in
children and adults, respectively. At present, there are some difficulties in establishing an accurate diagnosis of these neoplasms, due
to their heterogeneous cell morphology and distinct histological patterns. On the other hand, tumors recurrences have shown
conventional therapies to be ineffective, because they are not able to remove infiltrating or quiescent cells. There is evidence that has
helped to explain therapeutic failures and recurrences of tumors. It demonstrates the existence of Brain Tumor Stem Cells (BTSCs),
which were identified by Neural Stem Cell (NSC) markers. These BTSCs are capable of generating MB and GB, when transplanted
into immunodeficient mice. We propose that BTSCs acquire features from NSCs that have been described during nervous system
development. It is known these NSCs possess different proliferation rates and differentiation potentials that may be recreated by
BTSCs, and have been identified by molecular markers that include growth factor receptors. Therefore, identifying these cells will
allow determining the aggressiveness of MB and GB variants. This knowledge will be useful to establish a more accurate diagnosis; it
will also help to propose novel therapeutic targets. We have already standardized and established immunohistochemical procedures to
detect NSCs markers, such as Sox1, Sox2, LIFR, FGFR1, EGFR1 and BLBP. We have detected LIFR, FGFR1, EGFR1 and BLBP on
three MB variants, and found different expression patterns between LIFR and FGFR1, on the most aggressive histological variants,
which may correlate with poor clinical outcome.
Program/Abstract # 546
Transcriptomes of Proliferating Neural Stem Cells, Differentiating Progenitors and Newborn Neurons Identify Long Non-
Coding RNAs as Novel Players in Corticogenesis
Perez, Julieta Aprea; Prenninger, Silvia; Wessendorf, Elke (CRT-Dresden, Germany); Ghosh, Tanay (Paris, France); Alexopoulou,
Dimitra; Lesche, Mathias; Dahl, Andreas (CRT-Dresden, Germany); Groszer, Matthias (École des Neurosciences Paris, France);
Hiller, Michael; Calegari, Federico (CRT-Dresden, Germany)
Transcriptome analysis of somatic stem cells and their progeny is fundamental to identify the molecular mechanisms regulating the
transition from proliferation to differentiation. However, analysing transcriptomes of individual cell types in complex tissues remains
a challenge. We generated a RFP/GFP double-reporter mouse line to isolate proliferating neural stem cells, differentiating progenitors
and newborn neurons that coexist as intermingled cell populations in the developing cortex. Transcriptome sequencing of these three
cell types revealed numerous uncharacterized protein-coding genes and several long non-coding (lnc)RNAs with highly specific and
transient expression patterns. Most identified lncRNAs overlapped genes implicated in neurogenesis and shared with them a nearly
identical expression pattern suggesting that lncRNAs control neural stem cell differentiation by regulating the expression of cell fate
determinants. Finally, we investigated the function of one lncRNA during cortical development and found that it is involved in
neurogenic commitment of neural progenitors as well as survival of newborn neurons. Our study provides the most comprehensive
and quantitative transcriptome resource during the switch of neural stem from proliferation to differentiation to date and identifies
crucial roles of lncRNAs during mammalian corticogenesis.
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