Dlx5andDlx6expression 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 VgatΔDlx5-6 mice in which Dlx5 and Dlx6 are simultaneously inactivated in all GABAergic interneurons. VgatΔDlx5-6 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 VgatΔDlx5-6 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 VgatΔDlx5-6/+ and VgatΔDlx5-6 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 STATEMENTDlx5 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 (VgatΔDlx5-6 mice). Mutant mice have reduced anxiety-like and obsessive-compulsive behaviors. Interestingly, VgatΔDlx5-6 mice have a 25% body weight reduction and about 70% less white and brown adipose tissue; their general health status is excellent. VgatΔDlx5-6 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.

DLX5/6GABAergic expression affects social vocalization: implications for human evolution

“…Furthermore, we identify a DLX5/6-Neanderthalderived haplotype present in up to 8% of non-African alleles that includes enhancers controlling gene expression in the central nervous system (Fazel Darbandi, et al 2016) and sequences associated to either hyper-or hypo-socialization/vocalization pathologies such as Williams-Buren syndrome (Poitras, et al 2010) or ASDs (Gandal, et al 2018). Interestingly the DLX5/6-N-Haplotype is underrepresented in the genomes of healthy semi-supercentenarians suggesting an association between DLX5/6 brain expression and healthy aging reminiscent of what has been shown in mouse models (de Lombares, et al 2019).…”

“…This observation could be related to the 33% lifespan extension described for Dlx5/6 VgatCre mice, suggesting that the DLX5/6-N-Haplotype could regulate DLX5/6 neuronal expression (de Lombares, et al 2019). These data on semi-supercentenarians could be seen in the light of George Williams antagonistic pleiotropy theory (Williams 1957) who proposes that genes controlling more than one phenotypic trait can have been positively selected being favourable early in life and in adulthood but can become detrimental later in life (old age and extreme longevity), phases of life subjected to weaker evolutionary pressures (Williams 1957;De Benedictis and Franceschi 2006;Giuliani, et al 2017).…”

“…AHP, Anterior hypothalamic area; cc, corpus callosum; cx, cortex; DM, Dorsomedial hypothalamus; PVN, para-ventricular nucleus; SCh, suprachiasmatic nucleus; VMH, ventro medial hypothalamus). The social interaction behaviour of Dlx5/6 VgatCre/+ (n=10), Dlx5/6 VgatCre (n=9) and control (n=15) mice placed in the same cage with a control visitor was monitored using a protocol de Lombares, et al 2019) which associates computer vision and artificial intelligence to identify and categorize individual social interactions.…”

“…One of the targets of Foxp2 is the Dlx5/6 locus: the mouse line Foxp2-S321X, which does not produce Foxp2 protein, displays a more than 200-fold increased expression of Dlx6as1 (also known as Evf1/2 or Shhrs) (Vernes, et al 2006) a long noncoding RNA generated from the Dlx5/6 locus known to play a central role in the control of Dlx gene expression (Faedo, et al 2004;Feng, et al 2006). DLX5/6 are pleiotropic genes that control multiple aspects of embryonic development (Merlo, et al 2000), including limb, craniofacial and laryngeal morphogenesis (Beverdam, et al 2002;Depew, et al 2002;Robledo, et al 2002;Conte, et al 2016) and GABAergic neuronal differentiation and function (Perera, et al 2004;Wang, et al 2010;Cho, et al 2015;de Lombares, et al 2019).…”

“…Recently, by crossing Dlx5/6 flox mice with Vgat cre transgenic animals in which the "Cre-recombinase" gene is expressed selectively by GABAergic neurons, we have generated mice in which the Dlx5/6 DNA-binding capacity is reduced (Dlx5/6 VgatCre/+ ) or suppressed (Dlx5/6 VgatCre ) only in GABAergic neurons (de Lombares, et al 2019). Dlx5/6 VgatCre/+ and Dlx5/6 VgatCre mice present reduced anxiety, compulsivity and adiposity associated to a 33% life expectancy extension (de Lombares, et al 2019). In this study we show that Dlx5/6 VgatCre/+ and Dlx5/6 VgatCre mice present also different social behaviours and vocalization patterns when compared to their littermates.…”