Dendrite intercalation between epidermal cells tunes nociceptor sensitivity to mechanical stimuli in < i > Drosophila < /i > larvae

by Kory P. Luedke, Jiro Yoshino, Chang Yin, Nan Jiang, Jessica M. Huang, Kevin Huynh, Jay Z. Parrish An animal ’s skin provides a first point of contact with the sensory environment, including noxious cues that elicit protective behavioral responses. Nociceptive somatosensory neurons densely innervate and intimately interact with epidermal cells to receive these cues, however the mechanisms by which epider mal interactions shape processing of noxious inputs is still poorly understood. Here, we identify a role for dendrite intercalation between epidermal cells in tuning sensitivity ofDrosophila larvae to noxious mechanical stimuli. In wild-type larvae, dendrites of nociceptive class IV da neurons intercalate between epidermal cells at apodemes, which function as body wall muscle attachment sites, but not at other sites in the epidermis. From a genetic screen we identifiedmiR-14 as a regulator of dendrite positioning in the epidermis:miR-14 is expressed broadly in the epidermis but not in apodemes, andmiR-14 inactivation leads to excessive apical dendrite intercalation between epidermal cells. We found thatmiR-14 regulates expression and distribution of the epidermal Innexins ogre and Inx2 and that these epidermal gap junction proteins restrict epidermal dendrite intercalation. Finally, we found that altering the extent of epidermal dendrite intercalation had corresponding effects on nociception: increasing epidermal intercalation sensitized larvae to noxious mechanical inpu...
Source: PLoS Genetics - Category: Genetics & Stem Cells Authors: Source Type: research