An Immortal Flatworm May Aid In The Fight Against Deadly Diseases
Genetic similarities between humans and planarians, flatworms that are famously "immortal," may be the key to resisting the agents of diseases such as tuberculosis and a deadly strain of staph infection. An international research collaboration has produced a paper that details the asexual flatworms' significance in identifying natural human resistance to disease.
In 2012, molecular biologist Dr Aziz Aboobaker from the University of Nottingham published research which stated that planarians are able to bypass the aging process, and are therefore essentially immortal. Humans age as a result of the shortening of telomeres, which are nucleotide sequences that become eroded during the DNA replication process in cell division. The erosion of telomeres causes cell death, senescence, and cancer. Planarians are able to regenerate their telomeres during the fission process, while humans can only lengthen their telomeres through sexual reproduction. This maintenance of telomere length affords planarians remarkable regenerative properties; if they are cut in half, then its head will grow a new tail and its tail will grow a new head. Even more notably, they cannot die of old age.
Although we haven't been able to replicate their regenerative properties yet, we have been using their unique anatomical properties to discover new methods of fighting disease. When faced with pathogens such as tuberculosis, staph, and Legionnaire's disease, the flatworm's immune system is able to eliminate all of the bacteria. The researchers studied which genes were active in the immune response, and found that several of them, including a gene dubbed MORN2, are present in the human genome. They then stimulated human macrophages (white blood cells that digest pathogens) to over-express this gene. After this alteration, the macrophages were able to eliminate all of the pathogens.
This research not only has the potential to illuminate inherent genetic resistance to diseases, but could also tell us more about the nature of the diseases themselves. During this study, the researchers found that the agent of tuberculosis is able to remain in a latent state and attack when the immune system is weakened. This discovery, and others like it, may aid in the fight against antibiotic-resistant strains of TB.