A hedgehog homolog regulates gut formation in leech (Helobdella)
Developmental biology published in Development (2003)
Abstract
Signaling by the hedgehog (hh)-class gene pathway is essential for embryogenesis in organisms ranging from Drosophila to human. We have isolated a hh homolog (Hro-hh) from a lophotrochozoan species, the glossiphoniid leech, Helobdella robusta, and examined its expression by reverse transcription polymerase chain reaction (RT-PCR) and whole-mount in situ hybridization. The peak of Hro-hh expression occurs during organogenesis (stages 10-11). No patterned expression was detected within the segmented portion of the germinal plate during the early stages of segmentation. In stage 10-11 embryos, Hro-hh is expressed in body wall, foregut, anterior and posterior midgut, reproductive organs and in a subset of ganglionic neurons. Evidence that Hro-hh regulates gut formation was obtained using the steroidal alkaloid cyclopamine, which specifically blocks HH signaling. Cyclopamine induced malformation of both foregut and anterior midgut in Helobdella embryos, and no morphologically recognizable gonads were seen. In contrast, no gross abnormalities were observed in the posterior midgut. Segmental ectoderm developed normally, as did body wall musculature and some other mesodermal derivatives, but the mesenchymal cells that normally come to fill most of the coelomic cavities failed to develop. Taken with data from Drosophila and vertebrates, our data suggest that the role of hh-class genes in gut formation and/or neural differentiation is ancestral to the bilaterians, whereas their role in segmentation evolved secondarily within the Ecdysozoa.
Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.
Resumen
Hro-hh, a hedgehog homolog in Helobdella robusta, regulates body-wall, foregut, anterior/posterior midgut, reproductive organs, and ganglionic neuron development. Cyclopamine inhibition disrupts foregut and anterior midgut formation.
Por qué esto importa para la hirudoterapia
This study isolated and characterized a hedgehog (hh) homolog (Hro-hh) from the glossiphoniid leech Helobdella robusta, examining its expression during embryogenesis and its role in gut formation using cyclopamine to block HH signaling. The findings indicate that Hro-hh regulates foregut and anterior midgut development, with blocked signaling causing malformations in these structures as well as loss of gonads and coelomic mesenchymal cells. This work is purely developmental biology concerning a non-medicinal leech species and has no direct relevance to hirudotherapy, the leech secretome, or clinical ASH interests. It provides basic science insight into conserved signaling pathways across bilaterians but offers nothing applicable to therapeutic leech practice.
Citación
A hedgehog homolog regulates gut formation in leech (Helobdella).
Kang D et al. · Development (Cambridge, England), 2003
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Añadido a la biblioteca ASH: May 26, 2026 · Última actualización del sitio: June 18, 2026