Biology subjects

Selmanovic, D.

Publications and source records attributed to Selmanovic, D..

4 recordsLinked to original sources

bioRxiv2025

Single-Cell Resolution of Individual Variation in Hypothalamic Neurons Allows Targeted Manipulation Affecting Social Motivation

Despite decades of research, connecting molecular and cellular phenotypes to complex behavioral traits remains an elusive goal1. Social motivation exhibits individual trait variation2, which we hypothesize is mediated by molecular and cellular variability across hypothalamic neurons. To test this, we generated single-nucleus RNA-sequencing profiles3,4 of >120,000 neurons from tuberal hypothalamus and adjacent thalamus in 36 mice, balanced across sex and autism-associated mutation5, with all mice assessed for social motivation2. First, we show that molecular activation patterns predict behavior across individuals: specifically, activation of paraventricular Agtr1a+ (angiotensin receptor 1a) neurons predicted reduced social behavior. Subsequent inhibition of AGTR1A with telmisartan--an FDA-approved antihypertensive6--improved social orienting. Second, we show natural variation in neuronal proportions--likely arising from stochastic developmental events7--is sufficient to shape adult behavior even among genetically-identical individuals: we identified multiple neuronal populations whose relative abundance predicted social reward-seeking behavior. Chemogenetic inhibition of one such population, Nxph4+ neurons of the postero-lateral hypothalamus8, suppressed multiple aspects of social motivation. This work establishes proof-of-principle for an approach where single-cell genomics precisely maps neural substrates governing behavior. This approach revealed that stochastic variations in neuronal architecture deterministically influence social motivation, and enabled identification of therapeutically-actionable targets with immediate translational potential for disorders with social deficits.

genetics↗

bioRxiv2024

A survey of hypothalamic phenotypes identifies molecular and behavioral consequences of MYT1L haploinsufficiency in male and female mice.

The transcription factor MYT1L supports proper neuronal differentiation and maturation during brain development. MYT1L haploinsufficiency results in a neurodevelopmental disorder characterized by intellectual disability, developmental delay, autism, behavioral disruptions, aggression, obesity and epilepsy. While MYT1L is expressed throughout the brain, how it supports proper neuronal function in distinct regions has not been assessed. Some features of MYT1L Neurodevelopmental Syndrome suggest disruption of hypothalamic function, such as obesity and endocrine issues, and previous research showed changes in hypothalamic neuropeptide expression following knockdown in zebrafish. Here, we leveraged our heterozygous Myt1l mutant, previously shown to recapitulate aspects of the human syndrome such as hyperactivity, social challenges, and obesity, to examine the impact of MYT1L loss on hypothalamic function. Examining the molecular profile of the MYT1L haploinsufficient hypothalamus revealed a similar scale of disruption to previously studied brain regions, yet with region-specific roles for MYT1L, including regulation of neuropeptide systems. Alterations in oxytocin and arginine vasopressin cell numbers were also found. Behaviors studied included maternal care, social group hierarchies, and aggression, all of which were unchanged. Feeding and metabolic markers were also largely unchanged in MYT1L haploinsufficient mice, yet an interaction was observed between diet and MYT1L genotype on weight gain. Our findings here suggest that gross endocrine function was not altered by MYT1L haploinsufficiency, and that key sex-specific behaviors related to proper hypothalamic function remain intact. Further study is needed to understand the functional impact of the altered hypothalamic molecular profile and changes in neuropeptide cell numbers that result from MYT1L haploinsufficiency.

animal behavior and cognition↗

bioRxiv2024

Chromosomal and gonadal sex have differing effects on social motivation in mice

Plain English SummaryAs our brain develops, many factors influence how we behave later in life. The brain forms differently in males and females, potentially leading to sex variation seen in many behaviors including sociability. In addition, conditions defined by differences in social behaviors, such as autism, are diagnosed more in males than females. However, researchers dont know exactly how distinct sex factors, such as hormones and sex chromosome genes, lead to different behaviors in males and females. In this study, we used mouse models and tests of mouse behavior to explore these differences. Results show that sex hormones primarily contributed to differences in social motivation between sexes. Yet when we repeated these same assays in a mouse model of genetic liability for a human neurodevelopmental syndrome, we found that sex chromosome genes rather than sex hormones played a larger role in the behavioral consequences of impaired neurodevelopment. These insights can inform future research on the biological mechanisms of social behavior in the context of genetic liability for neurodevelopmental disorders. HighlightsO_LIFour-core genotype mouse model crossed with MYT1L heterozygous mouse revealed independent effects of chromosomal and gonadal sex on social motivation. C_LIO_LIMyt1l haploinsufficiency was associated with increased activity in both males and females. C_LIO_LIWhile females are more active, contributions of chromosomes and gonadal hormones to this sex effect are environment dependent. C_LIO_LIPresence of ovaries was associated with increased measures of social seeking and orienting regardless of genotype. C_LIO_LIChromosomal sex interacted with MYT1L genotype, with increased social orienting and seeking specifically in XX MYT1L heterozygous mice. C_LI BackgroundSex differences in brain development are thought to lead to sex variation in social behavior. Sex differences are fundamentally driven by both gonadal (i.e., hormonal) and chromosomal sex, yet little is known about the independent effects of each on social behavior. Further, mouse models of the genetic liability for the neurodevelopmental disorder MYT1L Syndrome have shown sex specific deficits in social motivation. In this study, we aimed to determine if hormonal or chromosomal sex primarily mediate the sex differences seen in mouse social behavior, both at baseline and in the context of Myt1l haploinsufficiency. MethodsFour-core genotype (FCG) mice, which uncouple gonadal and chromosomal sex, were crossed with MYT1L heterozygous mice to create eight different groups with unique combinations of sex factors and MYT1L genotype. A total of 131 mice from all eight groups were assayed for activity and social behavior via the open field and social operant paradigms. Measures of social seeking and orienting were analyzed for main effects of chromosome, gonads, and their interactions with Myt1l mutation. ResultsThe FCGxMYT1L cross revealed independent effects of both gonadal and chromosomal sex on activity and social behavior. Specifically, the presence of ovaries, and by extension the presence of ovarian hormones, increased overall activity, social seeking, and social orienting regardless of genotype. In contrast, sex chromosomes affected social behavior mainly in the MYT1L heterozygous group, with XX sex karyotype when combined with MYT1L genotype contributing to increased social orienting and seeking. ConclusionsGonadal and chromosomal sex have independent mechanisms of driving increased social motivation in females. Additionally, sex chromosomes may interact with neurodevelopmental mutations to influence sex variation in atypical social behavior.

animal behavior and cognition↗

bioRxiv2021

Sex significantly impacts the function of major depression-linked variants in vivo

Genome-wide association studies have discovered blocks of common variants--likely transcriptional-regulatory--associated with major depressive disorder (MDD), though the functional subset and their biological impacts remain unknown. Likewise, why depression occurs in females more frequently than males is unclear. We therefore tested the hypothesis that risk-associated functional variants interact with sex and produce greater impact in female brains. We developed methods to directly measure regulatory variant activity and sex interactions using massively parallel reporter assays (MPRAs) in the mouse brain in vivo, in a cell type-specific manner. We measured activity of >1,000 variants from >30 MDD loci, identifying extensive sex-by-allele effects in mature hippocampal neurons and suggesting sex-differentiated impacts of genetic risk may underlie sex bias in disease. Unbiased informatics approaches indicated that functional MDD variants recurrently disrupt sex hormone receptor binding sequences. We confirmed this with MPRAs in neonatal brains, comparing brains undergoing the masculinizing hormone surge to hormonally-quiescent juveniles. Our study provides novel insights into the influence of age, biological sex, and cell type on regulatory-variant function, and provides a framework for in vivo parallel assays to functionally define interactions between organismal variables like sex and regulatory variation. One-Sentence SummaryMassively parallel assays in vivo identified extensive functional and sex-interacting common variants in depression risk loci.

genetics↗