Gut-derived signals regulate metabolism, appetite, and behaviors important for mental health. We have performed a large-scale multidimensional screen to identify gut hormones and nutrient-sensing mechanisms in the intestine that regulate metabolism and behavior in the fruit fly Drosophila. We identified several gut hormones that affect fecundity, stress responses, metabolism, feeding, and sleep behaviors, many of which seem to act sex-specifically. We show that in response to nutrient intake, the enteroendocrine cells (EECs) of the adult Drosophila midgut release hormones that act via inter-organ relays to coordinate metabolism and feeding decisions. These findings suggest that crosstalk between the gut and other tissues regulates food choice according to metabolic needs, providing insight into how that intestine processes nutritional inputs and into the gut-derived signals that relay information regulating nutrient-specific hungers to maintain metabolic homeostasis.

Dysregulation of protein synthesis both globally and locally in neurons and astrocytes is a key feature of neurodegenerative diseases. Aberrant signalling through the Unfolded Protein Response (UPR) and related Integrated Stress Response (ISR) have become major targets for neuroprotection in these disorders. In addition, other homeostatic mechanisms and stress responses, including the cold shock response, appear to regulate local translation and RNA splicing to control synapse maintenance and regeneration and can also be targeted therapeutically for neuroprotection. We have defined the role of UPR/ISR and the cold-shock response in neurodegenerative disorders and have developed translational strategies targeting them for new treatments for dementia.

Major depressive disorder (MDD) is a sexually dimorphic disease. This sexual dimorphism is believed to result from sex-specific molecular alterations affecting functional pathways regulating the capacity of men and women to cope with daily life stress differently. Transcriptional changes associated with epigenetic alterations have been observed in the brain of men and women with depression and similar changes have been reported in different animal models of stress-induced depressive-like behaviors. In fact, most of our knowledge of the biological basis of MDD is derived from studies of chronic stress models in rodents. However, while these models capture certain aspects of the features of MDD, the extent to which they reproduce the molecular pathology of the human syndrome remains unknown and the functional consequences of these changes on the neuronal networks controlling stress responses are poorly understood. During this presentation, we will first address the extent by which transcriptional signatures associated with MDD compares in men and women. We will then transition to the capacity of different mouse models of chronic stress to recapitulate some of the transcriptional alterations associated with the expression of MDD in both sexes. Finally, we will briefly elaborate on the functional consequences of these changes at the neuronal level and conclude with an integrative perspective on the contribution of sex-specific transcriptional profiles on the expression of stress responses and MDD in men and women.