Bats’ ability to host deadly viruses without getting sick could help shed light on inflammation and ageing in humans.
Bats live very long and host numerous viruses, such as the Ebola virus, Nipah virus, severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) coronaviruses, that are extremely harmful when they infect humans and other animals.
They harbour so many of these pathogens without suffering from diseases. An international research team led by Duke-NUS Medical School, Singapore, has identified molecular and genetic mechanisms that allow bats to stay healthy while hosting viruses that kill other animals, according to a new study published in Nature Microbiology.
The secret is in the bat’s ability to limit inflammation.
Bats do not react to infection with the typical inflammatory response that often leads to pathological damage.
In humans, while the inflammatory response helps fight infection when properly controlled, it has also been shown to contribute to the damage caused by infectious diseases, as well as ageing and age-related diseases when it goes into overdrive.
The researchers found that the inflammation sensor that normally triggers the body’s response to fight off stress and infection, a protein called NLRP3, barely reacts in bats compared to humans and mice, even in the presence of high viral loads.
They also found unique variants of NLRP3 only present in bats that render the proteins less active in bats than in other species. These variations were observed in two very distinct species of bats – Pteropus alecto, a large fruit bat known as the Black Flying Fox, and Myotis davadii, a tiny vesper bat from China – indicating that they have been genetically conserved through evolution.
Further analysis comparing 10 bat and 17 non-bat mammalian NLRP3 gene sequences confirmed that these adaptations appear to be bat-specific.
What this implies, is that rather than having a better ability to fight infection, bats have a much higher tolerance for it. The dampening of the inflammatory response actually enables them to survive. [APBN]
Source: Ahn M, Anderson DE, Zhang Q, Tan CW, Lim BL, Luko K, Wen M, Chia WN, Mani S, Wang LC, Ng JHJ, Sobota RM, Dutertre CA, Ginhoux F, Shi ZL, Irving AT, Wang LF (2019). Dampened NLRP3-mediated inflammation in bats and implications for a special viral reservoir host. Nature Microbiology. DOI: 10.1038/s41564-019-0371-3