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:Major depressive disorder is one of the most common mental health conditions. Meningeal lymphatics are essential for drainage of molecules in the cerebrospinal fluid to the peripheral immune system. Their potential role in depression-like behaviour has not been investigated. Here, we show in mice, sub-chronic variable stress as a model of depression-like behaviour impairs meningeal lymphatics in females but not in males. Manipulations of meningeal lymphatics regulate the sex difference in the susceptibility to stress-induced depression- and anxiety-like behaviors in mice, as well as alterations of the medial prefrontal cortex and the ventral tegmental area, brain regions critical for emotional regulation. Together, our findings suggest meningeal lymphatic impairment contributes to susceptibility to stress in mice, and that restoration of the meningeal lymphatics might have potential for modulation of depression-like behaviour.
Project description:Mental health disorders often arise as a combination of environmental and genetic factors. The FKBP5 gene, encoding the GR co-chaperone FKBP51, has been uncovered as a key genetic risk factor for stress related illness. However, the exact cell type and region-specific mechanisms by which FKBP51 contributes to stress resilience or susceptibility processes remain to be unravelled. FKBP51 functionality is known to interact with the environmental risk factors age and sex, but so far data on behavioral, structural and molecular consequences of these interactions are still largely unknown. Here we report the cell type- and sex-specific contribution of FKBP51 to stress susceptibility and resilience mechanisms under the high-risk environmental conditions of an older age, by using two conditional knockout models within glutamatergic (Fkbp5Nex) and GABAergic (Fkbp5Dlx) neurons of the forebrain. Specific manipulation of Fkbp5 in these two cell types led to opposing effects on behavior, brain structure and gene expression profiles in a highly sex-dependent fashion. The results emphasize the role of FKBP51 as a key player in stress-related illness and the need for more targeted and sex-specific treatment strategies.
Project description:Vitamin D3 (VitD) insufficiency is postulated to represent a major modifiable risk factor for multiple sclerosis (MS). While low VitD levels strongly correlate with higher MS risk in white populations, this is not the case for other ethnic groups, suggesting the existence of a genetic component. Moreover, VitD supplementation studies in MS so far have not shown a consistent benefit. We sought to determine whether direct manipulation of VitD levels modulates central nervous system (CNS) autoimmune disease in a sex-by-genotype-dependent manner. To this end, we used a dietary model of VitD modulation, together with the autoimmune animal model of MS, experimental autoimmune encephalomyelitis (EAE). To assess the impact of genotype-by-VitD interactions on EAE susceptibility, we utilized a chromosome substitution (consomic) mouse model that incorporates the genetic diversity of wild-derived PWD/PhJ mice. High VitD was protective in EAE in female, but not male C57BL/6J (B6) mice, and had no effect in EAE-resistant PWD/PhJ (PWD) mice. EAE protection was accompanied by sex- and genotype-specific suppression of proinflammatory transcriptional programs in effector CD4 T effector cells, but not CD4 Treg cells. Decreased expression of proinflammatory genes was observed with high VitD in female CD4 T cells, specifically implicating a key role of MHC class II genes, interferon gamma, and Th1 cell-mediated neuroinflammation. In consomic strains, effects of VitD on EAE were also sex- and genotype-dependent, whereby high VitD: 1) was protective, 2) had no effect, and, 3) unexpectedly had disease-exacerbating effects. Systemic levels of 25(OH)D differed across consomic strains, with higher levels associated with EAE protection only in females. Analysis of expression of key known VitD metabolism genes between B6 and PWD mice revealed that their expression is genetically determined and sex-specific, and implicated Cyp27b1 and Vdr as candidate genes responsible for differential EAE responses to VitD modulation. Taken together, our results support the observation that the association between VitD status and MS susceptibility is genotype-dependent, and suggest that the outcome of VitD status in MS is determined by gene-by-sex interactions.
Project description:Aortic stenosis (AS) is a degenerative valve disease characterized by active remodelling of valve leaflets. The main hallmarks of stenotic aortic valves (AVs) include fibrosis, inflammation, osteogenesis and angiogenesis. Men and women develop these mechanisms differently. Galectin-3 (Gal-3) is a pro-inflammatory and pro-osteogenic lectin with a prominent role in the progression of AS. In this work, we aim to analyze potential sex-differences in the impact of Gal-3 in AS. 226 patients (61.50% men) with severe AS undergoing surgical valve replacement were recruited. In AVs, Gal-3 expression and its relationship with inflammatory, osteogenic and angiogenic markers was assessed. Valve interstitial cells (VIC) derived from AV tissue were primary cultured to perform in vitro experiments. Proteomic analysis revealed that Gal-3 is over-expressed in VICs of male AS patients. Gal-3 secretion also showed to be higher in men’s VICs as compared to women. In human AV tissue, Gal-3 protein levels were significantly higher in men, with stronger immunostaining in VICs with myofibroblastic phenotype and valve endothelial cells. Gal-3 levels in AVs were positively correlated with inflammatory markers in both sexes. Gal-3 expression was also positively correlated with osteogenic markers mainly in men’s AV, and with angiogenic molecules only in this sex.
Project description:Adult women are twice as likely as men to suffer from affective and anxiety disorders, although the mechanisms underlying heightened female stress susceptibility are incompletely understood. Recent findings in mouse Nucleus Accumbens (NAc) suggest a role for DNA methyltransferase-driven sex differences in genome-wide transcriptional profiles. However, the role of another epigenetic process—microRNA (miR) regulation—has yet to be explored. We exposed male and female mice to Subchronic Variable Stress (SCVS), a stress paradigm that produces depression-like behavior in female, but not male, mice, and performed next-generation mRNA and miR sequencing on NAc tissue. We applied a combination of differential expression, miR-mRNA network and functional enrichment analyses to characterize the transcriptional and post-transcriptional landscape of sex differences in NAc stress response. We find that male and female mice exhibit largely non-overlapping miR and mRNA profiles following SCVS. The two sexes also show enrichment of different molecular pathways and functions. Collectively, our results suggest that males and females mount fundamentally different transcriptional and post-transcriptional responses to SCVS and engage sex-specific molecular processes following stress. These findings have implications for the pathophysiology and treatment of stress-related disorders in women.
Project description:Drosophila heterochromatin protein 1- HP11 is believed to be involved in active transcription, transcriptional gene silencing, and the formation of heterochromatin2-7. However, little is known about the function of HP1 during development. Using a Gal4-induced RNA interference system, we show that conditional depletion of HP1 in transgenic flies results in preferential lethality in male flies. Cytological analysis of mitotic chromosomes reveals that HP1 depletion causes sex-biased chromosomal defects, including telomere fusions. The global levels of specific histone modifications, particularly the hallmarks of active chromatin, are preferentially increased in males as well. Expression analysis revealed that approximately twice as many genes are specifically regulated by HP1 in males compared to females. Furthermore, HP1-regulated genes showed greater enrichment for HP1 binding in males. Taken together, these results reveal that HP1 modulates chromosomal integrity, histone modifications, and transcription in a sex-specific manner. Keywords: sex-specific, HP1, gender comparison
Project description:Our study demonstrates differential expression of numerous autosomal miRNAs between the male and female developing human lung. Additionally, the expression of some miRNAs are modified by age across the pseudoglandular stage in a sex-specific way. Some of these differences in miRNA expression may impact susceptibility to pulmonary disease later in life. Our results suggest that sex-specific miRNA expression during human lung development may be a potential mechanism to explain sex-specific differences in lung development and may impact subsequent disease susceptibility