Investigating the molecular and neural mechanisms mediating social stress

Abstract

Maintaining an optimal social density is essential for the physical and mental health of humans and many other organisms. Stress caused by extreme social densities (ESD), including social isolation and crowding, can lead to different mental and physical health issues such as anxiety, depression, addiction and neurodegenerative diseases. However, the underlying molecular and neural mechanisms mediating the ESD-induced stress is poorly understood. In addition, it is also unclear about how the body senses and adapts to the long-term effects of ESD, including the associated behavioral and physiological changes. Drosophila melanogaster has been shown to be a versatile tool to study the neural circuits mediating social dynamics among individuals of the same species. Previous studies have shown that social isolation alters the behaviors in male flies, and our preliminary study on female flies also demonstrated that chronic ESD has altered behaviors including mating, feeding, and social spacing, as well as the level of major metabolites. To further understand the molecular mechanisms underlying how ESD affects female Drosophila, we have identified multiple differentially expressed genes (DEGs) associated with ESD using RNA-Sequencing. The DEGs are involved in pathways essential for cellular metabolism, oxidative stress, olfactory sensory pathways and neuronal protection. Based on our preliminary findings, we hypothesize that ESD systematically alters the physiology and behavior of Drosophila through a complex of molecular and sensory mechanisms. My study sheds light on how social density is perceived and processed by the brain and in turn regulates individual’s behavior and physiology and therefore provide insights into potential therapeutic targets of social stress related illnesses.