Neuropeptides and their functions in Hydra

Area of Science:

• Developmental Biology
• Neuroscience
• Marine Biology

Background:

• The freshwater cnidarian, Hydra magnipapillata, serves as a model organism for studying fundamental biological processes.
• Understanding peptide signaling is crucial for elucidating the regulation of development and physiology in simple metazoans.
• The 'primitive' nervous system of Hydra is often underestimated in its complexity and functional diversity.

Purpose of the Study:

• To systematically screen for and identify novel peptide signaling molecules in Hydra.
• To investigate the roles of identified neuropeptides in regulating developmental and physiological processes.
• To characterize the functions of specific peptide families, including LWamides and FRamides.

Main Methods:

• Initiation of the Hydra Peptide Project, a systematic peptide screening initiative.
• Identification and characterization of twelve neuropeptides, including members of the LWamide and FRamide families.
• Functional assays to determine the effects of neuropeptides on metamorphosis, budding, neuronal differentiation, and muscle contraction.

Main Results:

• Seven members of the LWamide family, sharing a GLWamide C-terminal motif, were identified; they induce metamorphosis in Hydractinia and bud detachment in Hydra.
• Neuropeptide Hym-355 was found to enhance neuronal differentiation by directing interstitial stem cells into the neuron pathway.
• Myoactive neuropeptide Hym-176 induces specific, reversible contraction of the ectodermal muscle in Hydra, even in nerve-cell-lacking epithelial regions. Two FRamides exhibit opposing myoactive functions.

Conclusions:

• The Hydra Peptide Project has identified novel neuropeptides with significant regulatory roles in development and physiology.
• Identified neuropeptides like LWamides, Hym-355, and Hym-176 demonstrate complex functions, including induction of metamorphosis, bud detachment, neuronal differentiation, and muscle contraction.
• The findings suggest that the nervous system of Hydra is more complex than previously assumed, highlighting sophisticated signaling mechanisms in this 'primitive' metazoan.