Project description:Social status is one of the strongest predictors of disease risk and mortality in humans, and often influences Darwinian fitness in social mammals more generally. To understand the biological basis of these effects, we combined a functional genomics approach with sequential social status manipulations in rhesus macaques to investigate how social status alters immune function. We demonstrate causal, but largely plastic, effects of social status on immune cell proportions, cell type-specific gene expression levels, and the gene expression and cytokine response to infection. Further, we identify specific transcription factor signaling pathways that explain these differences, particularly status-associated polarization of the TLR4 signaling pathway towards pro-inflammatory versus anti-viral responses. Our findings provide an unprecedented level of insight into the direct biological effects of social inequality on immune function, thus contributing to an improved understanding of social gradients in health and the evolution of social hierarchies. For social status, please refer to table S1 in the manuscript.
Project description:Social status is one of the strongest predictors of disease risk and mortality in humans, and often influences Darwinian fitness in social mammals more generally. To understand the biological basis of these effects, we combined a functional genomics approach with sequential social status manipulations in rhesus macaques to investigate how social status alters immune function. We demonstrate causal, but largely plastic, effects of social status on immune cell proportions, cell type-specific gene expression levels, and the gene expression and cytokine response to infection. Further, we identify specific transcription factor signaling pathways that explain these differences, particularly status-associated polarization of the TLR4 signaling pathway towards pro-inflammatory versus anti-viral responses. Our findings provide an unprecedented level of insight into the direct biological effects of social inequality on immune function, thus contributing to an improved understanding of social gradients in health and the evolution of social hierarchies. For social status, please refer to table S1 in the manuscript.
Project description:Social status is one of the strongest predictors of disease risk and mortality in humans, and often influences Darwinian fitness in social mammals more generally. To understand the biological basis of these effects, we combined a functional genomics approach with sequential social status manipulations in rhesus macaques to investigate how social status alters immune function. We demonstrate causal, but largely plastic, effects of social status on immune cell proportions, cell type-specific gene expression levels, and the gene expression and cytokine response to infection. Further, we identify specific transcription factor signaling pathways that explain these differences, particularly status-associated polarization of the TLR4 signaling pathway towards pro-inflammatory versus anti-viral responses. Our findings provide an unprecedented level of insight into the direct biological effects of social inequality on immune function, thus contributing to an improved understanding of social gradients in health and the evolution of social hierarchies. For social status, please refer to table S1 in the manuscript.
Project description:Social experiences are an important predictor of disease susceptibility and survival in humans and other social mammals. Chronic social stress is thought to generate a pro-inflammatory state characterized by elevated antibacterial defenses and reduced investment in antiviral defense. Here, we manipulated long-term social status in female rhesus macaques to show that social subordination alters the gene expression response to ex vivo bacterial and viral challenge. As predicted by current models, bacterial lipopolysaccharide polarizes the immune response such that low status corresponds to higher expression of genes in NF-κB dependent pro-inflammatory pathways and lower expression of genes involved in the antiviral response and type I interferon (IFN) signaling (see Snyder-Mackler et al. Science, 2016 doi:10.1126/science.aah3580 and GSE83304). Here we show that, counter to predictions, low status drives more exaggerated expression of both NF-κB and IFN-associated genes after cells are exposed to the viral mimic Gardiquimod. Status-driven gene expression patterns are not only linked to social status at the time of sampling, but also to social history (i.e., past social status), especially in unstimulated cells. However, for a subset of genes, we observed interaction effects in which females who fell in rank were more strongly affected by current social status than those who climbed the social hierarchy. Together, our results indicate that the effects of social status on immune cell gene expression depend on pathogen exposure, pathogen type, and social history – in support of social experience-mediated biological embedding in adulthood, even in the conventionally memory-less innate immune system.
Project description:Autism spectrum disorder (ASD) is a heterogenous neurodevelopmental disorder with complex pathophysiology including both genetic and environmental factors. Recent evidence demonstrates the gut microbiome and its resultant metabolome can influence brain and behavior and have been implicated in ASD. To investigate gene by microbiome interactions in a model for genetic risk of ASD, we utilize mutant mice carrying a deletion of the ASD-associated Shank3 gene (Shank3KO). Shank3KO have altered microbiome composition and function at baseline in addition to social deficits. Further depletion of the microbiome with antibiotics exacerbates social deficits in Shank3KO, and results in transcriptional changes in the frontal cortex. Supplementation with the microbial metabolite acetate leads to reversal of social behavioral phenotypes even in mice with a depleted microbiome, and significantly alters transcriptional regulation in the prefrontal cortex. These results suggest a key role for the gut microbiome and the neuroactive metabolite acetate in regulating ASD-like behaviors.
Project description:Group-living individuals experience immense risk of disease transmission and parasite infection. In social and in some non-social insects, disease control with immunomodulation arises not only via individual immune defenses, but also via infochemicals such as contact cues and (defensive) volatiles to mount a group-level immunity. However, little is known about whether activation of the immune system elicits changes in chemical phenotypes, which may mediate these responses. We here asked whether individual immune experience resulting from wounding or injection of heat-killed Bacillus thuringiensis (priming) leads to changes in the chemical profiles of female and male adult red flour beetles, Tribolium castaneum, which are non-social but gregarious. We analyzed insect extracts using GC-FID to study the chemical composition of (1) cuticular hydrocarbons (CHCs) as candidates for the transfer of immunity-related information between individuals via contact, and (2) stink gland secretions, with analysis of benzoquinones as main active compounds regulating ‘external immunity’. Despite a pronounced sexual dimorphism in CHC profiles, wounding stimulation led to similar profile changes in males and females with increases in the proportion of methyl-branched alkanes compared to naïve beetles. While changes in the overall secretion profiles were less pronounced, absolute amounts of benzoquinones were transiently elevated in wounded compared to naïve females. Responses to priming were insignificant in CHCs and secretions. We suggest that changes in different infochemicals after wounding may mediate immune status signaling in the context of both internal and external immune responses in groups of this non-social insect, thus showing parallels to social immunity.
Project description:Sperm competition theory predicts that males should tailor ejaculates according to their social status. Here we test this in a model vertebrate, the house mouse (Mus musculus domesticus), combining experimental data with a quantitative proteomics analysis of seminal fluid composition. Our analyses reveal that both sperm production and the relative production of proteins found in seminal fluid differ according to social dominance. Notably, whereas dominant males produce and ejaculate more sperm, subordinate males produce greater relative amounts of key proteins used in the formation of copulatory plugs. These findings have important implications for understanding the dynamics and outcome of sperm competition.