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Abstract The neurons of the melanocortin system regulate feeding and energy homeostasis through a combination of electrical and endocrine mechanisms. However, the molecular basis for this functional heterogeneity is poorly understood. Here, a voltage‐gated potassium (Kv+) channel named KCNB1 (alias Kv2.1) forms stable complexes with the leptin receptor (LepR) in a subset of hypothalamic neurons including proopiomelanocortin (POMC) expressing neurons of the Arcuate nucleus (ARHPOMC). Mice lacking functional KCNB1 channels (NULL mice) have less adipose tissue and circulating leptin than WT animals and are insensitive to anorexic stimuli induced by leptin administration. NULL mice produce aberrant amounts of POMC at any developmental stage. Canonical LepR‐STAT3 signaling—which underlies POMC production—is impaired, whereas non‐canonical insulin receptor substrate PI3K/Akt/FOXO1 and ERK signaling are constitutively upregulated in NULL hypothalami. The levels of proto‐oncogene c‐Fos—that provides an indirect measure of neuronal activity—are higher in arcuate NULL neurons compared to WT and most importantly do not increase in the former upon leptin stimulation. Hence, a Kv channel provides a molecular link between neuronal excitability and endocrine function in hypothalamic neurons.
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Integrin-KCNB1 potassium channel complexes regulate neocortical neuronal development and are implicated in epilepsy
Abstract Potassium (K+) channels are robustly expressed during prenatal brain development, including in progenitor cells and migrating neurons, but their function is poorly understood. Here, we investigate the role of voltage-gated K+channel KCNB1 (Kv2.1) in neocortical development. Neuronal migration of glutamatergic neurons was impaired in the neocortices of KCNB1 null mice. Migratory defects persisted into the adult brains, along with disrupted morphology and synaptic connectivity. Mice developed seizure phenotype, anxiety, and compulsive behavior. To determine whether defective KCNB1 can give rise to developmental channelopathy, we constructed Knock In (KI) mice, harboring the gene variantKcnb1R312H(R312H mice) found in children with developmental and epileptic encephalopathies (DEEs). The R312H mice exhibited a similar phenotype to the null mice. Wild type (WT) and R312H KCNB1 channels made complexes with integrins α5β5 (Integrin_K+channel_Complexes, IKCs), whose biochemical signaling was impaired in R312H brains. Treatment with Angiotensin II in vitro, an agonist of Focal Adhesion kinase, a key component of IKC signaling machinery, corrected the neuronal abnormalities. Thus, a genetic mutation in a K+channel induces severe neuromorphological abnormalities through non-conducting mechanisms, that can be rescued by pharmacological intervention. This underscores a previously unknown role of IKCs as key players in neuronal development, and implicate developmental channelopathies in the etiology of DEEs.
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- Award ID(s):
- 2030348
- PAR ID:
- 10373068
- Publisher / Repository:
- Nature Publishing Group
- Date Published:
- Journal Name:
- Cell Death & Differentiation
- Volume:
- 30
- Issue:
- 3
- ISSN:
- 1350-9047
- Format(s):
- Medium: X Size: p. 687-701
- Size(s):
- p. 687-701
- Sponsoring Org:
- National Science Foundation
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