Project description:Bats are increasingly studied as model systems for longevity and as natural hosts to some virulent viruses. Yet our ability to characterize immune mechanisms of viral tolerance and to quantify infection dynamics in wild bats is often limited by small sample volumes and few species-specific reagents. To address this, we demonstrate how proteomics can overcome these limitations by using data-independent acquisition-based shotgun proteomics (i.e., bottom-up proteomics) to survey the serum proteome of 17 vampire bats (Desmodus rotundus) from Belize. We focused this work on vampire bats, a species that has an obligate diet of blood and feeds on prey as diverse as sea lions, tapirs, livestock, and even humans, providing numerous opportunities for transmission of viruses (e.g., rabies virus, adenovirus, herpesvirus) to and from these recipient hosts. Using just 2 μL of sample and relatively short separations of undepleted serum digests, we identified 361 proteins across five orders of magnitude. We also used known bat virus proteomes to identify Rh186 from Macacine herpesvirus 3 and ORF1a from Middle East respiratory syndrome-related coronavirus, indicating that mass spectrometry-based techniques show promise for pathogen detection. Our results demonstrate the feasibility and capabilities of serum proteomic analyses in wild bats, including possibilities to simultaneously detect host immunological components and viral infection as well as to establish preliminary ranges of vampire bat proteins for comparison with other mammalian blood proteomes. Overall, these results can be used to design targeted mass-spectrometry assays to quantify immunological markers and detect pathogens. More broadly, our findings also highlight the application of proteomics in advancing wildlife immunology and pathogen surveillance.
Project description:Bats are natural reservoirs for a large range of emerging viruses that cause lethal diseases in humans and domestic animals, but remain asymptomatic in bats. Understanding the host-pathogen interactions relies on the availability of relevant models including susceptible cells, derived from viral target tissues. To obtain bat cell types pertinent for the study of viral infection, we applied somatic reprogramming approach to Pteropus primary cells as initial substrates. Using the novel combination of three transcription factors: ESRRB, CDX2 and c-MYC, we generated reprogrammed cells exhibiting stem cells features.
Project description:To examine the fundamental immunity in bats, particularly the status of their innate immune system in the basal healthy state, we profile Pteropus alecto bat tissue with Deep NGS coverage. This is coupled to a paired experiment where bats were stimulated in vivo with various PRR ligands to activate immune pathways.
Project description:To examine the fundamental immunity in bats, particularly the status of their innate immune system in the basal healthy state, we profile Eonycteris spelaea bat tissue with Deep NGS coverage. This is coupled to a paired experiment where bats were stimulated in vivo with various PRR ligands to activate immune pathways.
Project description:Background: Coevolution between pathogens and their hosts decreases host morbidity and mortality. Bats can tolerate viruses which can be lethal to other vertebrate orders, including humans. Bat adaptations to infection include localized immune response, early pathogen sensing, high interferon expression without pathogen stimulation, and regulated inflammatory response. The immune reaction is costly, and bats suppress high-cost metabolism during torpor. In the temperate zone, bats hibernate in winter, utilizing a specific behavioural adaptation to survive detrimental environmental conditions and lack of energy resources. Hibernation torpor involves major physiological changes that pose an additional challenge to bat-pathogen coexistence. Here, we compared bat cellular reaction to viral challenge under conditions simulating hibernation, evaluating the changes between torpor and euthermia. Results: We infected the olfactory nerve-derived cell culture of Myotis myotis with an endemic bat pathogen, European bat lyssavirus 1 (EBLV-1). After infection, the bat cells were cultivated at two different temperatures – 37 ◦ C and 5 ◦ C - to examine the cell response during conditions simulating euthermia and torpor, respectively. The mRNA isolated from the cells was sequenced and analysed for differential gene expression attributable to the temperature and/or infection treatment. In conditions simulating euthermia, infected bat cells produce an excess signalling by multitude of pathways involved in apoptosis and immune regulation influencing proliferation of regulatory cell types which can, in synergy with other produced cytokines, contribute to viral tolerance. We found no up- or downregulated genes expressed in infected cells cultivated at conditions simulating torpor compared to non-infected cells cultivated under the same conditions. When studying the reaction of uninfected cells to the temperature treatment, bat cells show an increased production of heat shock proteins (HSPs) with chaperone activity, improving the bat’s ability to repair molecular structures damaged due to the stress related to the temperature change. Conclusions: The lack of bat cell reaction to infection in conditions simulating hibernation may contribute to the virus tolerance or persistence in bats. Together with the cell damage repair mechanisms induced in response to hibernation, the immune regulation may promote bats’ ability to act as reservoirs of zoonotic viruses such as lyssaviruses.
Project description:Hearing mediates many behaviors critical for survival in echolocating bats, including foraging and navigation. Although most mammals are susceptible to progressive age-related hearing loss, the evolution of biosonar, which requires the ability to hear low-intensity echoes from outgoing sonar signals, may have selected against the development of hearing deficits in bats. Many echolocating bats exhibit exceptional longevity and rely on acoustic behaviors for survival to old age; however relatively little is known about the aging bat auditory system. In this study, we used DNA methylation to estimate the ages of wild-caught big brown bats (Eptesicus fuscus) and measured hearing sensitivity in young and aging bats using auditory brainstem responses (ABRs) and distortion product otoacoustic emissions (DPOAEs). We found no evidence for hearing deficits in bats up to 12.5 years of age, demonstrated by comparable thresholds and similar ABR and DPOAE amplitudes across age groups. We additionally found no significant histological evidence for cochlear aging, with similar hair cell counts, afferent, and efferent innervation patterns in young and aging bats. Here we demonstrate that big brown bats show minimal evidence for age-related hearing loss and therefore represent informative models for investigating mechanisms that may preserve hearing function over a long lifetime.
Project description:Bats can harbor many pathogens without showing disease. However, the mechanisms by which bats resolve these infections or limit pathology remain unclear. To illuminate the bat immune response to coronaviruses, viruses with high public health significance, we will use serum proteomics to assess broad differences in immune proteins of uninfected and infected vampire bats (Desmodus rotundus). In contrast to global profiling techniques of blood such as transcriptomics, proteomics provides a unique perspective into immunology, as the serum proteome includes proteins from not only blood but also those secreted from proximal tissues. Here, we expand our recent work on the serum proteome of wild vampire bats (Desmodus rotundus) to better understand CoV pathogenesis. Across 19 bats sampled in 2019 in northern Belize with available sera, we detected CoVs in oral or rectal swabs from four individuals. We used data independent acquisition-based mass spectrometry to profile and compare the undepleted serum proteome of these 19 bats. These results will provide much needed insight into changes in the bat serum proteome in response to coronavirus infection.
Project description:Bats harbor high-impact zoonotic viruses in absence of clinical disease, which has been recently associated with unique features of their immune system. They seem to restrict inflammation and possibly limit disease manifestation to a minimum. In-depth characterization of cellular immunity in bats is yet largely missing, and imprinting of age and development on immune cell compartments remains unexplored. We employed single-cell transcriptomics and established immunostaining panels to investigate the immune cell populations peripheral blood for juvenile and adult Egyptian Rousette bats (ERB).