Bats are remarkable little creatures, with a long lifespan and an impressive resistance to both cancer and viral infection that has researchers very interested. So how have they managed to get blessed with these traits?
“In terms of the immune system, I want to be a bat,” said Dr Linfa Wang, professor in the emerging diseases program at Duke-NUS Medical School in Singapore and a founding adviser to biotech company Paratus Sciences Corp., in a statement. The flying mammals are “not that different from a human, but the things they can do we can only dream of,” Wang explained, being able to withstand “incredible” biological pressures.
A separate team of researchers recently sequenced the genomes of two bat species – the Jamaican fruit bat (Artibeus jamaicensis) and the Mesoamerican mustached bat (Pteronotus mesoamericanus) – to unlock their secrets.
“These investigations are the first step towards translating research on the unique biology of bats into insights relevant to understanding and treating aging and diseases, such as cancer, in humans,” lead author of the study, Dr Armin Scheben, said in a statement.
The authors of the study explain that the extraordinary immune systems and cancer resistance of bats “may have arisen as a result of coevolution of bats with viruses and that a need for enhanced DNA repair in the face of elevated reactive oxygen species (ROS) may have been a consequence of powered flight.”
The researchers compared bat genomes with those of humans, mice, dogs, pigs, and horses. They spotted 105 gene families that were smaller and 14 gene families that were larger in the most recent common ancestor of bats, with 39 of the 119 families being related to the immune system.
Proteins called interferons (IFNs) may have a key role, with the authors hypothesizing that “by relying on the potentially more potent IFN-ω rather than IFN-α, bats may further enhance their antiviral responses.”
Bats are also great at avoiding inflammation, with the paper noting that “a combination of expansions of antiviral genes and losses of proinflammatory genes may contribute to the dampened inflammatory response and viral tolerance in bats.” The switch to IFN-ω may help compensate for having less inflammation, which is usually a response to harmful things like pathogens. “If these properties of IFN-ω can be established, they may open the door to new therapeutic uses of IFN-ω,” the paper explains.
Genetic adaptations were also found in 46 cancer-related genes, and 33 tumor suppressors showed signs of positive selection, which the authors say suggests a “possible link to the unusually low incidence of cancer in bats.” They continue to explain that “cancer-related genes were enriched more than 2-fold among [positively selected genes] on the bat ancestral branch relative to a set of mammalian branches.”
The paper also explains that there is a lot of overlap when it comes to genes related to the immune system and cancer, with genes associated with the immune system suppressing tumors and being involved in cancer surveillance.
Bats also have incredibly good DNA repair, with six DNA repair genes also showing signs of positive selection. “Enhanced DNA repair has been proposed as a mechanism for longevity and cancer resistance in various mammals including bats,” the authors explain.
Understanding bats’ amazing genetic feats could bring many benefits to humanity, including a better understanding of how zoonotic diseases spread. Bats are both resistant to and hosts of many different viruses. “They seem to be genetically wired to support viruses,” Dr Thomas Zwaka, founder of Paratus and a stem cell researcher at the Icahn School of Medicine at Mount Sinai, said.
The study is published in the journal Genome Biology and Evolution.