Biology subjects

Ibarra-Garcia-Padilla, R.

Publications and source records attributed to Ibarra-Garcia-Padilla, R..

3 recordsLinked to original sources

bioRxiv2024

Expansion of a neural crest gene signature following ectopic MYCN expression in sympathoadrenal lineage cells in vivo

Neural crest cells (NCC) are multipotent migratory stem cells which originate from the neural tube during early vertebrate embryogenesis. NCC give rise to a variety of cell types within the developing organism, including neurons and glia of the sympathetic nervous system. It has been suggested that failure in correct NCC differentiation leads to several diseases, including neuroblastoma (NB). During normal NCC development, MYCN is transiently expressed to promote NCC migration, and its downregulation precedes neuronal differentiation. Overexpression of MYCN has been linked to high-risk and aggressive NB progression. For this reason, understanding the effect overexpression of this oncogene has on development of NCC-derived sympathoadrenal progenitors (SAP), which later give rise to sympathetic nerves, will help elucidate the developmental mechanisms that may prime the onset of NB. Here, we found that overexpressing human EGFP-MYCN within SAP lineage cells in zebrafish led to the transient formation of an abnormal SAP population which displayed expanded and elevated expression of NCC markers, while paradoxically also co-expressing SAP and neuronal differentiation markers. The aberrant NCC signature was corroborated with in vivo time lapse confocal imaging in zebrafish larvae, which revealed transient expansion of sox10 reporter expression in MYCN overexpressing SAPs during the early stages of SAP development. In these aberrant MYCN overexpressing SAP cells, we also found evidence of dampened BMP signaling activity, indicating that BMP signaling disruption occurs following elevated MYCN expression, and suggesting BMP is functionally important for the NCC to SAP differentiation transition. In agreement, we discovered that pharmacological inhibition of BMP signaling was sufficient to create an aberrant NCC gene signature in SAP cells, phenocopying MYCN overexpression. Together, our results suggest that MYCN overexpression in SAPs disrupts their differentiation by eliciting abnormal NCC gene expression programs, and dampening BMP signaling response, having developmental implications for the priming of NB in vivo.

developmental biology↗

bioRxiv2022

In Toto imaging of early Enteric Nervous System Development reveals that gut colonization is tied to proliferation downstream of Ret

The enteric nervous system (ENS) is a vast intrinsic network of neurons and glia within the gastrointestinal tract and is largely derived from enteric neural crest cells (ENCCs) that emigrate into the gut during vertebrate embryonic development. Study of ENCC migration dynamics and their genetic regulators provides great insights into fundamentals of collective cell migration and nervous system formation, and are a pertinent subject for study due to their relevance to the human congenital disease, Hirschsprung disease (HSCR). For the first time, we performed in toto gut imaging and single-cell generation tracing of ENCC migration in WT and a novel ret heterozygous background zebrafish (retwmr1/+) to gain insight into ENCC dynamics in vivo. We observed that retwmr1/+ zebrafish produced fewer ENCCs while localized along the gut, which failed to reach the hindgut, resulting in HSCR-like phenotypes. Specifically, we observed a proliferation dependent migration mechanism, where cell divisions were associated with inter-cell distances and migration speed. Lastly, we detected a premature neuronal differentiation gene expression signature in retwmr1/+ ENCCs, collectively suggesting that Ret signaling may function to regulate maintenance of a stem-state in ENCCs.

developmental biology↗

bioRxiv2020

An atlas of neural crest lineages along the posterior developing zebrafish at single-cell resolution

Neural crest cells (NCCs) are vertebrate stem cells that give rise to various cell types throughout the developing body in early life. Here, we utilized single-cell transcriptomic analyses to delineate NCC-derivatives along the posterior developing vertebrate, zebrafish, during the late embryonic to early larval stage, a period when NCCs are actively differentiating into distinct cellular lineages. We identified several major NCC/NCC-derived cell-types including mesenchyme, neural crest, neural, neuronal, glial, and pigment, from which we resolved over three dozen cellular subtypes. We dissected gene expression signatures of pigment progenitors delineating into chromatophore lineages, mesenchyme subtypes, and enteric NCCs transforming into enteric neurons. Global analysis of NCC derivatives revealed they were demarcated by combinatorial hox gene codes, with distinct profiles within neuronal cells. From these analyses, we present a comprehensive cell-type atlas that can be utilized as a valuable resource for further mechanistic and evolutionary investigations of NCC differentiation.

developmental biology↗