Dlx5 and Dlx6 expression in GABAergic neurons controls behavior, metabolism, healthy aging and lifespan.

ABSTRACT Dlx5 and Dlx6 encode two homeobox transcription factors expressed by developing and mature GABAergic interneurons. During development Dlx5/6 are important for the differentiation of Parvalbumin ( Pvalb )-expressing neurons. Perinatal lethality of homozygous mice in which Dlx5/6 have been constitutively deleted has, so far, hindered the study of the function of these genes in adult neurons. We first show that Dlx5 and Dlx6 are expressed by all subclasses of adult cortical GABAergic neurons. Then we analyse Vgat ΔDlx5-6 mice in which Dlx5 and Dlx6 are simultaneously inactivated in all GABAergic interneurons. Vgat ΔDlx5-6 mice present a behavioral pattern suggesting reduction of anxiety and obsessive-compulsive activities. They rapidly access and spend more time in the central region of an open field, bury few marbles in the marble burying test and show little interest in nest building. Male and female 20-month-old Vgat ΔDlx5-6 animals have the same size as their normal littermates, but present a 25% body weight reduction associated with a marked decline in white and brown adipose tissue. Remarkably, both Vgat ΔDlx5-6/+ and Vgat ΔDlx5-6 mice present a 33% longer median survival than their control littermates. Hallmarks of biological aging such as motility, adipose deposition and coat conditions are improved in mutant animals. Our data imply that GABAergic interneurons can regulate mammalian healthspan and lifespan through Dlx5/6 -dependent mechanisms. Understanding these regulations can be an entry point to unravel the processes through which the brain affects body homeostasis and, ultimately, longevity and healthy aging. SIGNIFICANCE STATEMENT Dlx5 and Dlx6 are transcription factors controlling several developmental processes, including GABAergic neuronal migration and differentiation. To study their function in adult brain, we selectively inactivated both genes in GABAergic interneurons ( Vgat ΔDlx5-6 mice). Mutant mice have reduced anxiety-like and obsessive-compulsive behaviors. Interestingly, Vgat ΔDlx5-6 mice have a 25% body weight reduction and about 70% less white and brown adipose tissue; their general health status is excellent. Vgat ΔDlx5-6 mice have a median survival about 33% longer than their control littermates and hallmarks of biological aging are improved. Dlx5/6-dependent regulations in GABAergic neurons could be an entry point to understand how the brain determines the psychophysiological status of the body and, ultimately, longevity and healthy aging.