Title: Constraints in protein biosynthesis of multi-functional fat body tissue lead to a trade-off between reproduction and immunity

Speaker: Dr. Vanika Gupta, Cornell University

Timing: 21 October 2021 6PM-8PM IST

Lab: http://www.lazzaro.entomology.cornell.edu/index.html

Abstract

The constraints imposed by using the same tissue for multiple purposes can result in sub-optimal performance of each process resulting in tradeoffs, and it is largely unknown how tissues balance their roles. The insect fat body tissue performs multiple functions overlapping with several mammalian tissues; especially immunity and reproduction which are often seen to be negatively correlated. We hypothesized that the fat body achieves its multiple functions through division of labor resulting in cellular subpopulations performing specific functions. We further hypothesized that physiological perturbations affect specific subsets of the tissue, including the robust systemic immune response triggered by bacterial infection. We sequenced individual nuclei from the dissected fat body tissues of Drosophila melanogaster females, experimentally manipulated to perform combinations of reproductive and immune functions. We used flies which were either challenged with a Gram-negative bacteria Providencia rettgeri or unchallenged, under both reproductively active and inactive conditions. We identified transcriptionally heterogeneous cell populations with most of the fat body tissue consisting of multi-tasking cells displaying physiology-dependent transcriptional response. Pseudo temporal analysis revealed that the fat body specifically undergo rapid transcriptional shifts in response to physiological perturbations. We found that the yolk proteins marked the most abundant fat body subpopulations across all treatments. Bacterial infection followed with increased yet heterogeneous expression of immunity genes including anti-microbial peptides, bomanins etc. While the mating response induced large metabolic changes in the tissue. The high expression of ribosomal biogenesis genes under un-induced physiological state suggested that the fat body tissue uses protein translation to control its various functions. We provide evidence that limited protein synthesis capacity of the multi-functional fat body cells under reproductively active condition leads to lower immunocompetence. Such internal physiological limitations could explain wide prevalence of tradeoffs such as reproduction-immunity tradeoff. Our results also highlight how translation control could be the key feature enabling multi-functional tissues to perform various functions.

It is a Zoom meeting.