Alteration of nociceptive Schwann cells in a mouse model of peripheral neuropathy in prediabetic condition
Diabetic peripheral neuropathy (DPN) characterized by progressive and symmetrical sensory abnormalities is one of the earliest and main complications of diabetes. DPN is characterized by heterogeneous sensory symptoms such as chronic pain, tingling, burning or loss of sensation. Nociceptive Schwann cells (nSCs), a recently identified subtypes of dermal Schwann cells support terminal nerve fibers in mouse skin and contribute to mechanical sensation and neuropathic pain. While terminal nerve fibers density is basically evaluated in DPN models, there is currently few data about nSCs number and integrity during early stage of DPN. In the present study, we used a mouse model of prediabetes by using high-fat diet (HFD) fed mice to determine if there are quantitative differences in terminal nerve fiber density, nSCs number and cellular extensions between control and prediabetic neuropathic mice. In this study, we identified L1CAM as a reliable marker of nSCs currently characterized by the expression of S100beta and Sox10. Interestingly, we observed a decrease in intraepidermal nerve fiber density (IENFD) associated to a significant reduction of nSCs in the glabrous foot skin of neuropathic mice. Overall, this study identifies L1CAM as a new marker of nSCs and indicates that these cells are impaired during prediabetic peripheral neuropathy.