Large‐scale genome sampling reveals unique immunity and metabolic adaptations in bats

Abstract

Comprising more than 1,400 species, bats possess adaptations unique among mammals including powered flight, unexpected longevity, and extraordinary immunity. Some of the molecular mechanisms underlying these unique adaptations includes DNA repair, metabolism and immunity. However, analyses have been limited to a few divergent lineages, reducing the scope of inferences on gene family evolution across the Order Chiroptera. We conducted an exhaustive comparative genomic study of 37 bat species, one generated in this study, encompassing a large number of lineages, with a particular emphasis on multi-gene family evolution across immune and metabolic genes. In agreement with previous analyses, we found lineage-specific expansions of the APOBEC3 and MHC-I gene families, and loss of the proinflammatory PYHIN gene family. We inferred more than 1,000 gene losses unique to bats, including genes involved in the regulation of inflammasome pathways such as epithelial defence receptors, the natural killer gene complex and the interferon-gamma induced

Lifespan Extension in Long-Lived Vertebrates Rooted in Ecological Adaptation

“…All organisms generate damage and also develop mechanisms that protect against this damage. The regulation of biological processes and pathways in extremely long-lived animals ( Moreno Santillán et al, 2021 ; Wilkinson et al, 2021 ) shows patterns of adaptation that are distinct from those of short-lived animals, and this is reflected in the damage that they produce ( Bundgaard et al, 2019 ; Kacprzyk et al, 2021 ). Accordingly, modulation of related pathways in short-lived species is known to extend the lifespan ( Leiser et al, 2013 ).…”

Induced bacterial sickness causes inflammation but not blood oxidative stress in Egyptian fruit bats (Rousettus aegyptiacus)

“…Bats are particularly special with respect to their pathogen load because they are reservoirs of many important zoonotic pathogens without developing any ostensible symptoms ( Baker et al , 2013 ; Mandl et al , 2018 ; Moreno Santillán et al , 2021 ; Wibbelt et al , 2010 ). Lack of clinical symptoms is particularly interesting in relation to a high number of viral strains and other intracellular pathogens they harbour, while, on the other hand, bats show standard-to-extreme pathology following infection with certain extracellular pathogens, such as bacteria and fungi ( Brook and Dobson, 2015 ).…”

Reservoir host immunology and life history shape virulence evolution in zoonotic viruses

“…where 𝛾 scales the rapidity of recovery with the immune cell density. We can then allow the virus to evolve its within-host growth rate (𝑟) to maximize its reproductive success at the invasion fitness ( [13] for the SIS model and [16] for the SIR model, above). In within-host terms, the invasion fitness takes on the following general form, under assumptions of constant tolerance:…”

“…This may be due, in part, to unique bat resistance mechanisms, which include constitutive expression of antiviral cytokines in some species 9 and enhanced autophagy 10 and heat-shock protein expression in others 11 . While these protracted inflammatory responses would be pathological in most mammals, bats have evolved unique mechanisms of mitigating inflammation, including loss of PYHIN 12,13 and downregulation of NLRP3 14 inflammasome-forming gene families, dampened STING-dependent interferon activation 15 , and diminished caspase-1 inflammatory signaling 16 . As an apparent by-product of these adaptations that enable flight, bats maintain long lifespans 17 and tolerate inflammation incurred by the recruitment of immune cells to viral infections 8 .…”