Project description:Rational: Major depressive disorder (MDD) is a leading cause of disease burden worldwide. While the incidence, symptoms and treatment of MDD all point toward major sex differences, the molecular mechanisms underlying this sexual dimorphism remain largely unknown. Methods: Here, combining differential expression and gene coexpression network analyses, we provide a comprehensive characterization of male and female transcriptional profiles associated with MDD across 6 brain regions. We overlap our human profiles with those from a mouse model of chronic variable stress and capitalize on converging pathways to define molecular and physiological mechanisms underlying the expression of stress susceptibility in males and females. Results: Our results show a major rearrangement of transcriptional patterns in MDD, with limited overlap between males and females, an effect seen in depressed humans and in stressed mice. We identify key regulators of sex-specific gene networks underlying MDD and confirm their sex-specific impact as mediators of stress susceptibility. For example, downregulation of the female-specific hub gene DUSP6 in prefrontal cortex mimics stress susceptibility in females only by increasing ERK signaling and pyramidal neuron excitability. Such DUSP6 downregulation also recapitulates the transcriptional remodeling that occurs in PFC of depressed females. Conclusions: Together, our findings reveal dramatic sexual dimorphism at the transcriptional level in MDD and highlight the importance of studying sex-specific treatments for this disorder.
Project description:Depression is a common disorder that affects women at twice the rate of men. Here we report that long non-coding RNAs (lncRNAs), a recently discovered class of regulatory transcripts, represent about one-third of the differentially expressed genes in the brains of depressed humans, and display complex region- and sex-specific patterns of regulation. We identified the primate-specific, neuronal-enriched gene, linc00473, as downregulated in prefrontal cortex of depressed females but not males. Using viral-mediated gene transfer to express linc00473 in mouse prefrontal cortex neurons, we mirrored the human sex-specific phenotype by inducing stress resilience solely in female mice. This sex-specific phenotype was accompanied by changes in synaptic function and gene expression selectively in female mice and, along with studies of human neuron-like cells in culture, implicates linc00473 as a CREB effector. Together, our studies identify linc00473 as a female-specific driver of stress resilience that is aberrant in female depression.
Project description:Stress-related psychiatric disorders and the stress system show prominent differences between men and women. These sex differences are detectable at the transcriptional level but we lack cell-type specific information. Here, using single-cell transcriptomics, we identify cell-type-specific signatures of acute restraint stress in the paraventricular nucleus of the hypothalamus - a central hub of the stress response - in male and female mice. Further, we show that a history of chronic mild stress alters these acute stress signatures in a sex-specific way. Using this dataset, we identified oligodendrocytes as a major target for sex-specific effects of stress. This dataset provides the first molecular resource for an in-depth dissection of the interplay between cell types and sex on the mechanisms of the stress response, offering the transcriptomes of thousands of individual cells.
Project description:Bladder cancer (BLCA) is more common in men but more aggressive in women. A common model used to study sex-based differences in cancer biology is murine BLCA generated by N-butyl-N-(4-hydroxybutyl)-nitrosamine (BBN). While tumors in this model have been profiled, these profiles provided limited information on the tumor microenvironment. Hence, we applied single-cell RNA sequencing to characterize cell type specific transcriptional differences between male and female BBN induced tumors and then studied their human relevance. We found proportion and gene expression differences in the epithelial and non-epithelial subpopulations between male and female tumors. Of translational importance, expression of several genes was found to predict sex specific survival in several human BLCA datasets. We also noted a male biased CD8 T cell exhaustion program in this model that correlates highly with androgen receptor activity. Our study identified novel and clinically relevant sex specific transcriptional signatures and validates the relevance of the BBN model for studying sex differences in human BLCA. This work highlights the importance of considering sex as a biological variable in cancer marker development.
Project description:Neuropathic pain is a chronic debilitating condition with a high comorbidity with depression. Clinical reports and animal studies have suggested that both the medial prefrontal cortex (mPFC) and the anterior cingulate cortex (ACC) are critically implicated in regulating the affective symptoms of neuropathic pain. Neuropathic pain induces long-term structural, functional and biochemical changes in both regions, which are thought to be regulated by multiple waves of gene transcription. However, the similarity and differences in the transcriptomic profiles changed by neuropathic pain between these regions are largely unknown. Furthermore, women are more susceptible to pain and depression than men. The molecular mechanisms underlying this sexual dimorphism remain to be explored. Here, we performed RNA sequencing and analyzed the transcriptomic profiles of the mPFC and ACC of female and male mice at 2 weeks after spared nerve injury (SNI), an early time point when the mice began to show mild depressive symptoms. Our results show that the SNI-induced transcriptomic changes in female and male mice are largely distinct. Interestingly, the female mice exhibit more robust transcriptomic changes in the ACC than male, whereas the opposite pattern occurs in the mPFC. Cell type enrichment analyses reveal that the differentially expressed genes involve genes enriched in both neurons and various types of glia. We further performed Gene Set Enrichment Analysis (GSEA), which reveal significant de-enrichment of myelin sheath development in both female and male mPFC after SNI. In the female ACC, gene sets for synaptic organization and mitochondria function are enriched, and gene sets for extracellular matrix are de-enriched after SNI, while such signatures are absent in male ACC. Collectively, these findings reveal sexual dimorphism at the transcriptional level induced by neuropathic pain, and provide novel therapeutic targets for chronic pain and its associated affective disorders.
Project description:Major depressive disorder (MDD) is a pervasive and debilitating syndrome characterized by mood disturbances, anhedonia, and alterations in cognition. While the prevalence of MDD is twice as high for women compared to men, little is known about the molecular mechanisms that drive sex differences in depression susceptibility. We discovered that Slit Guidance Ligand 1 (SLIT1), a secreted protein essential for axonal navigation and molecular guidance in cellular migration, is downregulated in the ventromedial prefrontal cortex (vmPFC) of depressed women compared to healthy controls, but not depressed men. This sex-specific downregulation of Slit1 was also observed in the vmPFC of mice exposed to chronic variable stress. To identify a causal, sex-specific role for SLIT1 in depression-related behavioral abnormalities, we performed knockdown (KD) of Slit1 expression in the vmPFC of male and female mice. When combined with stress exposure, vmPFC Slit1 KD reflected the human condition by inducing a sex-specific increase in anxiety- and depression-like behavioral abnormalities in female mice with no effect seen in male mice. Further, we found that vmPFC Slit1 KD caused a pronounced reduction in dendritic arborization and concomitant alterations to electrophysiological properties of vmPFC pyramidal neurons in females. Additionally, RNA-sequencing analysis of the vmPFC following Slit1 KD in female mice revealed an augmented transcriptional stress signature. Together, our findings establish a crucial role for SLIT1 in regulating neurophysiological and transcriptional responses to stress within the vmPFC, and provide mechanistic insight into novel signaling pathways and molecular factors influencing sex differences in depression susceptibility.
Project description:Here, we selected >1000 variants from over 30 depression-associated loci using brain epigenomic data, and functionally assayed them using in vivo functional assays in the mouse brain to examine sex-by-genotype interactions. We identify extensive sex-by-allele effects in mature hippocampus, suggesting genetic risk and thus disease mechanisms may be distinct between the sexes. Unbiased informatics approaches indicated a role for nuclear hormone receptors, which was supported by . Further, comparative analysis of allelic function in the neonatal mouse brain, during a key between developmental neonates during the masculinizing testosterone surge, and in the adult hippocampus—a region of interest in depression pathology—but not at 10 days old, a older hormonally quiescent developmental stage juveniles. Our study provides novel insights into depression genetics as influenced by age, biological sex, and cell type, and provides a framework for in vivo parallel assays at a scale not previously shown possible to functionally define interactions between sex and disease variation.