The Hemodynamically-Regulated Vascular Microenvironment Promotes Migration of the Steroidogenic Tissue during Its Interaction with Chromaffin Cells in the Zebrafish Embryo

PLOS ONE, Dec 2019

Background While the endothelium-organ interaction is critical for regulating cellular behaviors during development and disease, the role of blood flow in these processes is only partially understood. The dorsal aorta performs paracrine functions for the timely migration and differentiation of the sympatho-adrenal system. However, it is unclear how the adrenal cortex and medulla achieve and maintain specific integration and whether hemodynamic forces play a role. Methodology and Principal Findings In this study, the possible modulation of steroidogenic and chromaffin cell integration by blood flow was investigated in the teleostean counterpart of the adrenal gland, the interrenal gland, in the zebrafish (Danio rerio). Steroidogenic tissue migration and angiogenesis were suppressed by genetic or pharmacologic inhibition of blood flow, and enhanced by acceleration of blood flow upon norepinephrine treatment. Repressed steroidogenic tissue migration and angiogenesis due to flow deficiency were recoverable following restoration of flow. The regulation of interrenal morphogenesis by blood flow was found to be mediated through the vascular microenvironment and the Fibronectin-phosphorylated Focal Adhesion Kinase (Fn-pFak) signaling. Moreover, the knockdown of krüppel-like factor 2a (klf2a) or matrix metalloproteinase 2 (mmp2), two genes regulated by the hemodynamic force, phenocopied the defects in migration, angiogenesis, the vascular microenvironment, and pFak signaling of the steroidogenic tissue observed in flow-deficient embryos, indicating a direct requirement of mechanotransduction in these processes. Interestingly, epithelial-type steroidogenic cells assumed a mesenchymal-like character and downregulated β-Catenin at cell-cell junctions during interaction with chromaffin cells, which was reversed by inhibiting blood flow or Fn-pFak signaling. Blood flow obstruction also affected the migration of chromaffin cells, but not through mechanosensitive or Fn-pFak dependent mechanisms. Conclusions and Significance These results demonstrate that hemodynamically regulated Fn-pFak signaling promotes the migration of steroidogenic cells, ensuring their interaction with chromaffin cells along both sides of the midline during interrenal gland development.

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The Hemodynamically-Regulated Vascular Microenvironment Promotes Migration of the Steroidogenic Tissue during Its Interaction with Chromaffin Cells in the Zebrafish Embryo

Liu Y-W (2014) The Hemodynamically-Regulated Vascular Microenvironment Promotes Migration of the Steroidogenic Tissue during Its Interaction with Chromaffin Cells in the Zebrafish Embryo. PLoS ONE 9(9): e107997. doi:10.1371/journal.pone.0107997 The Hemodynamically-Regulated Vascular Microenvironment Promotes Migration of the Steroidogenic Tissue during Its Interaction with Chromaffin Cells in the Zebrafish Embryo Chih-Wei Chou 0 You-Lin Zhuo 0 Zhe-Yu Jiang 0 Yi-Wen Liu 0 Sheng-Ping Lucinda Hwang, Institute of Cellular and Organismic Biology, Taiwan 0 Department of Life Science, Tunghai University , Taichung , Taiwan Background: While the endothelium-organ interaction is critical for regulating cellular behaviors during development and disease, the role of blood flow in these processes is only partially understood. The dorsal aorta performs paracrine functions for the timely migration and differentiation of the sympatho-adrenal system. However, it is unclear how the adrenal cortex and medulla achieve and maintain specific integration and whether hemodynamic forces play a role. Methodology and Principal Findings: In this study, the possible modulation of steroidogenic and chromaffin cell integration by blood flow was investigated in the teleostean counterpart of the adrenal gland, the interrenal gland, in the zebrafish (Danio rerio). Steroidogenic tissue migration and angiogenesis were suppressed by genetic or pharmacologic inhibition of blood flow, and enhanced by acceleration of blood flow upon norepinephrine treatment. Repressed steroidogenic tissue migration and angiogenesis due to flow deficiency were recoverable following restoration of flow. The regulation of interrenal morphogenesis by blood flow was found to be mediated through the vascular microenvironment and the Fibronectin-phosphorylated Focal Adhesion Kinase (Fn-pFak) signaling. Moreover, the knockdown of kruppel-like factor 2a (klf2a) or matrix metalloproteinase 2 (mmp2), two genes regulated by the hemodynamic force, phenocopied the defects in migration, angiogenesis, the vascular microenvironment, and pFak signaling of the steroidogenic tissue observed in flow-deficient embryos, indicating a direct requirement of mechanotransduction in these processes. Interestingly, epithelial-type steroidogenic cells assumed a mesenchymal-like character and downregulated b-Catenin at cell-cell junctions during interaction with chromaffin cells, which was reversed by inhibiting blood flow or Fn-pFak signaling. Blood flow obstruction also affected the migration of chromaffin cells, but not through mechanosensitive or Fn-pFak dependent mechanisms. Conclusions and Significance: These results demonstrate that hemodynamically regulated Fn-pFak signaling promotes the migration of steroidogenic cells, ensuring their interaction with chromaffin cells along both sides of the midline during interrenal gland development. - Data Availability: The authors confirm that all data underlying the findings are fully available without restriction. All relevant data are within the paper and its Supporting Information files. Funding: CWC, YLZ, ZYJ, and YWL were supported by Ministry of Science and Technology (http://web1.most.gov.tw/) grants (101-2313-B-029-001, 102-2628-B029-002-MY3 and 102-2321-B-400-018). The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: The authors have declared that no competing interests exist. Although blood vessels have long been known to respond to hemodynamic forces through mechanotransduction, only recently have researchers begun to understand the influence of hemodynamics on organogenesis through modulation of cellular behaviors, the extracellular matrix (ECM) microenvironment, as well as cell signaling events [1]. The early zebrafish embryo does not rely on blood circulation to transport oxygen [2], making it an excellent in vivo model for studying the effect of blood flow on development. Various genetic and pharmacological approaches have been developed in the zebrafish model, which have revealed the crucial role of hemodynamics in the morphogenesis of heart, kidney, and brain vasculature [3,4,5,6]. Moreover, it is possible to study the role of hemodynamics in establishing the architecture of endocrine tissues in the zebrafish embryo, since the specification and differentiation of a variety of endocrine cells proceed even in the complete absence of vasculature [7,8,9,10,11]. How the adrenal cortex and medullaarising because of distinct cell fate decisions in physically separated precursor cells assemble to form the adrenal gland remains incompletely understood. The adrenal cortex is comprised of steroidogenic cells differentiated from the intermediate mesoderm, while the medulla contains chromaffin cells that originate from the neural crest and are subsequently segregated from the sympatho-adrenal lineage [12]. Mice deficient in the transcription fa (...truncated)


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Chih-Wei Chou, You-Lin Zhuo, Zhe-Yu Jiang, Yi-Wen Liu. The Hemodynamically-Regulated Vascular Microenvironment Promotes Migration of the Steroidogenic Tissue during Its Interaction with Chromaffin Cells in the Zebrafish Embryo, PLOS ONE, 2014, 9, DOI: 10.1371/journal.pone.0107997