Size matters for potential diagnostic tool

Dr Michael Gantier

Significant research over the past decade has shown that small molecules known as microRNAs could be used to detect illness, with many scientists excited about its potential for use in early diagnostic tests.

MicroRNAs can be detected in small quantities in fluids like blood and urine, which could make them particularly useful for detecting blood-based illnesses such as bacterial-driven septicaemia, as recently suggested in a Nature publication (Seeley et al., Nature 2018).

However, an extended study by Hudson Institute scientist Dr Michael Gantier has shown some of these discoveries around microRNAs as biomarkers of septicaemia could be compromised because some microRNA sequences are modified when a patient has an active immune system.

Dr Gantier investigated the impact of an active immune system on the length of microRNAs and found that immune activation upon bacterial infection results in a reduction in the size of selected microRNAs.

“This is a critical finding, since the techniques currently used to detect microRNAs are affected by their length.”

Effectively, immune activation induced by many pathogens could lead to a misrepresentation of microRNA quantification in some cases. Our analyses reinforces the need to account for length variations before study of their use,” Dr Gantier said.

With so much excitement around the use of microRNAs to diagnose disease, Dr Gantier said this finding needs to be considered when evaluating the research in this area.

“In line with our previous findings, we found that immune activation had a profound impact on the length of microRNAs – with most being shortened,” Dr Gantier said.

What are microRNAs?

MicroRNAs are small molecules found in plants, animals and some viruses. They are involved in switching on and off different genes. The first microRNA was discovered in the early 1990s, with research in the field increasing significantly over the past decade (with more than 80,000 publications on the topic)

Collaborators:

Katherine Pillman, Gregory Goodall and Cameron Bracken (University of South Australia).