Different Requirements for GFR alpha 2-Signaling in Three Populations of Cutaneous Sensory Neurons

作者：Kupari Jussi; Airaksinen Matti S^*

来源：PLos One, 2014, 9(8): e104764.

DOI：10.1371/journal.pone.0104764

Many primary sensory neurons in mouse dorsal root ganglia (DRG) express one or several GFR alpha's, the ligand-binding receptors of the GDNF family, and their common signaling receptor Ret. GFR alpha 2, the principal receptor for neurturin, is expressed in most of the small nonpeptidergic DRG neurons, but also in some large DRG neurons that start to express Ret earlier. Previously, GFR alpha 2 has been shown to be crucial for the soma size of small nonpeptidergic nociceptors and for their target innervation of glabrous epidermis. However, little is known about this receptor in other Ret-expressing DRG neuron populations. Here we have investigated two populations of Ret-positive low-threshold mechanoreceptors that innervate different types of hair follicles on mouse back skin: the small C-LTMRs and the large A beta-LTMRs. Using GFR alpha 2-KO mice and immunohistochemistry we found that, similar to the nonpeptidergic nociceptors, GFR alpha 2 controls the cell size but not the survival of both C-LTMRs and A beta-LTMRs. In contrast to the nonpeptidergic neurons, GFR alpha 2 is not required for the target innervation of C-LTMRs and A beta-LTMRs in the back skin. These results suggest that different factors drive target innervation in these three populations of neurons. In addition, the observation that the large Ret-positive DRG neurons lack GFR alpha 2 immunoreactivity in mature animals suggests that these neurons switch their GFR alpha signaling pathways during postnatal development.

• 出版日期2014-8-11