Patterning mechanisms of branched organs - PubMed (original) (raw)

Review

Patterning mechanisms of branched organs

Pengfei Lu et al. Science. 2008.

Abstract

Branching morphogenesis is one of the earliest events essential for the success of metazoans. By branching out and forming cellular or tissue extensions, cells can maximize their surface area and overcome space constraints posed by organ size. Over the past decade, tremendous progress has been made toward understanding the branching mechanisms of various invertebrate and vertebrate organ systems. Despite their distinct origins, morphologies and functions, different cell and tissue types use a remarkably conserved set of tools to undergo branching morphogenesis. Recent studies have shed important light on the basis of molecular conservation in the formation of branched structures in diverse organs.

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Figures

Fig. 1

Branching morphogenesis in mouse organs. (A to C) Immunofluorescent staining of E-cadherin in the branching epithelium of whole-mount salivary gland (A), lung (B) and kidney (C) from embryos at E13.5 to E15. (D) Branches of mammary epithelium derived from progenitors that were marked by expression of green and red fluorescent proteins as described previously (32).

Fig. 2

Anatomy of the branching “engine.” A schematic presentation of various branched tissues: neuron (A), vasculature (B), Drosophila trachea (C) and air sacs (D), and mammary gland (E). Note the finger-like projections of the neuronal growth cone (A) and those of tip cells (green) of endothelium during angiogenesis (B) and Drosophila air sacs during larval development (D). To become tip cells, cells inhibit each other to take the leading position. In endothelium (B) and Drosophila trachea (C), mutual inhibition depends on Notch signaling. In the mammary gland, mutual inhibition depends on TGF-β signaling (E).

Fig. 3

Communication between epithelium, nerves, and blood vessels. Epithelium secretes NGF and VEGF (green) to attract nerves and vessels, respectively. Nerves also secrete VEGF (blue) to attract small arteries to track alongside nerve fibers. Blood vessels produce artemin and neurotrophin-3 (not shown), neurotrophic guidance signals, to guide neuronal axons.

Fig. 4

Stroma role in development of vertebrate branched organs. A schematic presentation of the epithelium and stroma during mammary gland development. Stroma, which has a heterogeneous cell population, plays an important role in determining branching patterns (blue arrows and bars indicate stimulatory and inhibitory cues acting on the epithelium). Stroma also regulates biology of stem cells by contributing to a presumptive stem cell “niche.”

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Patterning mechanisms of branched organs - PubMed (original) (raw)