Deletion of the insulin receptor in sensory neurons increases pancreatic insulin levels

• Published in: Experimental neurology Vol. 305; pp. 97 - 107
• Main Authors: Grote, Caleb W., Wilson, Natalie M., Katz, Natalie K., Guilford, Brianne L., Ryals, Janelle M., Novikova, Lesya, Stehno-Bittel, Lisa, Wright, Douglas E.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-07-2018
• Subjects: Animals; Beta cell; Blood Glucose - metabolism; Dorsal root ganglia; Female; Gene Deletion; Insulin; Insulin - metabolism; Insulin receptor; Islet; Male; Mice; Mice, Knockout; Mice, Transgenic; Microfilament Proteins - biosynthesis; Microfilament Proteins - genetics; Mouse models; Neuropathy; Pancreas; Pancreas - cytology; Pancreas - metabolism; Receptor, Insulin - deficiency; Receptor, Insulin - genetics; Sensory neuron; Sensory Receptor Cells - metabolism; Dorsal root ganglia; Mouse models; Beta cell; Sensory neuron; Neuropathy; Islet; Insulin receptor; Pancreas; Gene deletion; Insulin
• ISSN: 0014-4886; 1090-2430; 1090-2430
• DOI: 10.1016/j.expneurol.2018.04.002

Insulin is known to have neurotrophic properties and loss of insulin support to sensory neurons may contribute to peripheral diabetic neuropathy (PDN). Here, genetically-modified mice were generated in which peripheral sensory neurons lacked the insulin receptor (SNIRKO mice) to determine whether disrupted sensory neuron insulin signaling plays a crucial role in the development of PDN and whether SNIRKO mice develop symptoms of PDN due to reduced insulin neurotrophic support. Our results revealed that SNIRKO mice were euglycemic and never displayed significant changes in a wide range of sensorimotor behaviors, nerve conduction velocity or intraepidermal nerve fiber density. However, SNIRKO mice displayed elevated serum insulin levels, glucose intolerance, and increased insulin content in the islets of Langerhans of the pancreas. These results contribute to the growing idea that sensory innervation of pancreatic islets is key to regulating islet function and that a negative feedback loop of sensory neuron insulin signaling keeps this regulation in balance. Our results suggest that a loss of insulin receptors in sensory neurons does not lead to peripheral nerve dysfunction. The SNIRKO mice will be a powerful tool to investigate sensory neuron insulin signaling and may give a unique insight into the role that sensory neurons play in modifying islet physiology.
•Mice were generated in which peripheral sensory neurons lacked the insulin receptor (SNIRKO mice).•A lack of insulin receptors on sensory neurons does not lead to peripheral nerve dysfunction.•SNIRKO mice display elevated insulin and impaired glucose tolerance.•Disruption of insulin signaling in sensory neurons may impact insulin and glucose regulation.