The amazing relationship of bats with viruses

A stem cell study reveals that bats have developed mechanisms of tolerance to viruses, a finding that could shed light on the unique properties of bats in relation to their remarkable response against aging and cancer.

The team that carried out the study is led by Marion Déjosez and Arturo Marin, both from the Icahn School of Medicine, attached to the Mount Sinai Medical Center in the US city of New York.

Understanding crucial and unique aspects of bat life has so far been limited by the absence of cellular models for study. Researchers from the Doñana Biological Station (EBD), belonging to the Higher Council for Scientific Research (CSIC) in Spain, have participated in this study, which has made it possible to generate the first induced pluripotent cells (iPSC) from bats. In addition, this new methodology has revealed the close evolutionary relationship between bats and viruses. In fact, it opens the door to study how viruses survive, spread and evade the immune system through molecular adaptations to their hosts.

The findings of the EBD team, in collaboration with a group attached to the Mount Sinai Medical Center in the US city of New York led by researchers Thomas Zwaka and Adolfo García-Sastre, may help to clarify the properties of the bats that allow them to have such a remarkable response against aging and cancer.

Based on the inventories of refuges carried out in collaboration with the Junta de Andalucía, researchers Javier Juste and Carlos Ibáñez, from the EBD, selected the species (Rhinolophus ferrumequinum) and the most suitable bat colony for the study. With the collaboration of different institutions, it was possible to obtain samples and send the base material for the study in record time, despite the extreme difficulties of confinement in the first phase of the COVID-19 pandemic.

“Our study suggests that bats have evolved mechanisms to tolerate a large number of viral sequences, and may be more closely related to viruses than previously thought,” said lead author Thomas Zwaka. “This takes on new relevance as many bat species have been shown to tolerate and survive groups of viruses that cause high mortality rates in humans. The reason could be a modulation of the innate immune response of bats, which makes them virus-tolerant and asymptomatic hosts,” he adds.

Close-up of the face of a bat, in profile. (Photo: NPS)

A new methodology

Until now, there were no reliable cellular models to study the biology of bats or their responses to viral infections, making it difficult to understand their genomic adaptations. The new methodology developed in this work has made it possible to obtain induced pluripotent cells from tissue samples of the great horseshoe bat (Rhinolophus ferrumequinum) provided by the CSIC team. This species was selected because it belongs to a group of bats that are typically asymptomatic carriers of coronaviruses, including some closely related to SARS-CoV-2.

According to Adolfo García-Sastre, “the most extraordinary finding has been the presence of large vesicles in bat stem cells filled with viruses belonging to the main viral families, including coronaviruses, without compromising the cells’ ability to proliferate and grow. This could suggest a new paradigm for virus tolerance, as well as a symbiotic relationship between bats and viruses, or if viruses are serving as agents and editors in aspects of host biology in ways that influence their patterns. evolutionary.”

For their part, researchers from the Doñana Biological Station, Javier Juste and Carlos Ibáñez, announce that they hope that “bats, unfairly reviled by society, help us understand and use the special mechanisms of tolerance to viral infections that they have developed , and its response to the tactics employed by viruses to evade the immune system” in our own response to viral infections.

The study is titled “Bat pluripotent stem cells reveal unusual entanglement between host and viruses”. And it has been published in the academic journal Cell. (Source: Erika López / CSIC)