Mechanisms facilitating microbial co-inheritance - PROJECT SUMMARY Eukaryotic cells are home to a diversity of organelles, symbionts, and pathogens that are often co-inherited across cell lineages and from parent to progeny. Across humans, animal models, and arthropod vectors of pathogens, intracellular microbial community dynamics are associated with numerous effects on host physiology that ultimately result in disease. These include mitochondrial diseases, exacerbated clinical symptoms of co-acquired pathogens, altered transmission dynamics of vector-borne pathogens, interactive effects on host immunity and metabolism, and even dysbiosis of the host gut microbiome. There is great interest in defining the factors that promote or inhibit co-inheritance of intracellular bacteria due to the combination of their direct and indirect effects on animal health and for their potential use as anti-pathogen agents. We propose to use a suite of insect models to investigate the factors that regulate co-inheritance of intracellular microbes with a focus on Wolbachia: alpha-proteobacteria, related to the intracellular human pathogens Anaplasma, Rickettsia, and Ehrlichia. Unlike their close relatives, Wolbachia inhabit the cells of arthropods and nematodes and manipulate host biology to facilitate vertical transmission via the maternal germline. The consequences of Wolbachia infections are diverse and include reproductive isolation between host populations, matriline sweeps, protection against secondary infections with pathogens, and even host speciation. Furthermore, some arthropods harbor multiple, stably co-transmitted strains of Wolbachia that must compete for host resources and space in the germline. Importantly, these Wolbachia-mediated phenotypes are currently being applied to manage vector-borne pathogens, and, there is significant applied interest in leveraging coinfections of Wolbachia to fine-tune and expand management programs. Given the applied interest in Wolbachia and its broad success as an endosymbiont of ecdysozoans, they are an attractive model for understanding the mechanisms of coinfection. Our long-term goals are to define the mechanisms behind host-microbe and microbe-microbe interactions that ultimately determine inheritance and evolution of these associations. This proposal derives from our published work and preliminary data that has given us techniques to manipulate and track intracellular infections, our ability to perturb a naturally stable coinfection, and our discovery that intra-organismal niche partitioning plays a key role in coinfection stability. We propose to use a combination of techniques including high throughput analysis of transcriptomes, multiplexing spectral microscopy, and molecular and cell biology approaches to accomplish the following Specific Aims: (1) Define factors that facilitate co-establishment of intracellular microbes, (2) Identify features of stable coinfections that facilitate evolutionary stability. We anticipate this work will identify conserved mechanisms that regulate intracellular infections, as well as provide foundational knowledge to support the development of therapeutic strategies focused on intracellular microbes.
