Researchers found 90 genes involved in primates hibernation

A study including the Research Program on Biomedical Informatics (GRIB) joint research programme of the Hospital del Mar Medical Research Institute (IMIM) and the Department of Experimental and Health Sciences of the UPF (DCEXS), the Duke Lemur Center, and the Duke University has, for the first time, been looking at gene regulation in hibernating primates. They studied the fat-tailed dwarf lemur (Cheirogaleus medius). This is a very little-studied species and exceptional as it is the only primate capable of hibernating, subsisting on the lipids it has stored in its tail over the rest of the year. The project is also one of the few works on hibernation that uses a modern technique known as RNAseq which provides a global view of which genes are expressed and quantifies these. This is the first genomic data on this species.

The work involved studying a total of four individuals that live in the Duke Lemur Center: adipose tissue samples were taken from the tail at different times of the year, including while the animals were hibernating, and RNAseq was applied to find out which genes are involved in hibernation. Hibernation, despite its name, is not a response to cold, but to a lack of resources. These lemurs hibernate in Madagascar, which is almost tropical, and they do so during the dry season because they cannot find food.

The computation and data analysis was carried out at the GRIB by José Luis Villanueva-Cañas, a researcher in the Evolutionary Genomics group led by Mar Albà, and the animal monitoring, sample extraction, and experiments were the responsibility of Sheena Faherty, a researcher at Duke University in the group of Anne Yoder.

According to Villanueva-Cañas, currently a researcher at the Institute of Evolutionary Biology (UPF-CSIC) "Apart from the biological interest, studying hibernation is also fascinating from a medical point of view, as we are talking about animals that dramatically decrease their metabolism (temperature, breathing rate, food intake, brain activity, etc.) to levels that would be deadly to species without this adaptation." Villanueva added that "Since we find many mammals capable of hibernation, without any clear pattern involved, we believe that the common ancestor of all mammals might have had the ability to hibernate. This would mean that many of the genes involved are also present in humans and it is just a matter of finding out which they are and how to manipulate them for our interests". The researchers found 90 genes, including genes involved in lipid metabolism, that regulate appetite and biological rhythms.

Researchers who study this kind of unique species explain that it is important because they could disappear in the near future if the destruction of their habitat continues. These are amazing secrets of nature that die with species and can never be recovered. The fact that we can look at primates, which are much closer to us than other hibernating species, increases the chances of making long-term discoveries that can be translated to humans.

Even though these are just the first steps, the researchers believe that in the distant future, discoveries made in the field of hibernation could have surgical application. For example, it may be possible to decrease body temperature without causing tissue damage, giving doctors more time in emergency situations. It has even been suggested that this knowledge could be used by astronauts in short space flights, such as within the solar system, to save resources, reduce the problems of living in small spaces for months, and particularly with regard to the amount of room within the ships, which is very limited.

At the moment, the next steps involve conducting a similar study on closely related species but this time looking at them in the wild and not in captivity as was done in this study.

Image: Cheirogaleus medius. Source: Duke Lemur Center.

Reference work: "Gene expression profiling in the hibernating primate, Cheirogaleus medius" Sheena L. Faherty; José Luis Villanueva-Canas; Peter H. Klopfer; M. Mar Albà; Anne D. Yoder. Genome Biology and Evolution 2016; doi:10.1093/gbe/evw163