Researchers use open-access genetic data to reveal a unique picture of ageing
Using publicly available datasets, researchers have found that genes involved in infections and inflammatory responses are highly expressed with age, suggesting links between infection/inflammation and the ageing process.
What happens to our bodies as we age, and why? On the face of it, the answers may seem obvious, but the biological mechanisms involved in ageing are not yet completely understood. These questions are more pertinent than ever, as improvements in healthcare mean that the human population is ageing rapidly, but frailty and chronic illness still frequently accompany old age. Uncovering the mysteries of ageing will help researchers to understand the relationship between ageing and disease, paving the way for people to be healthier during their final years.
With this in mind, a group of researchers in India and the United States has investigated gene expression during ageing in a new study published in the open-access journal 4Open. The study reveals age-related changes in genes involved in immunity, typically indicating a decline in immune function. However, genes involved in inflammation and the body’s response to specific infections also change with age. This implies that elderly people might have dysregulations in inflammatory processes and in dealing with infections.
Open-access data, open-access publication
To study gene expression activity in youth and old age, the research team used freely available microarray datasets, generated when previous researchers assessed genetic differences in large groups of people. “Working in India, with limited experimental resources, we wanted to show that interesting biological questions can be asked and meaningful answers obtained using only open-source tools and data,” explains Dr Bibhu Prasad Parida of Fakir Mohan University, India, principal author on the study. Fittingly, the authors chose to publish their study, which benefitted from open-access data, in 4Open, a multidisciplinary open-access journal.
Ageing and our response to disease
The researchers analysed genetic data covering almost 250 individuals, who they classified as ‘young’ (under 30 years) or 'older' (over 30 years). Using bioinformatics techniques, they compared gene expression in the 'young' and 'older' groups and identified 185 genes with age-related altered expression.
The altered genes are involved in a wide variety of biological processes, but some patterns did emerge from the expression data. The older group showed changes in genes linked to immune function, many of which suggested impaired immunity. Strikingly, this group also showed changes in genes involved in inflammation, and in immune responses to infection with specific pathogens such as Staph or Salmonella. This suggests that inflammation and opportunistic infections are hallmarks of ageing.
The team’s results suggest that the multitude of infections we are exposed to throughout our lives, our susceptibility to infection and changes in how our body responds to infection, are key characteristics of ageing.
Conclusions and the future
“Immune system and infection-mediated effects in ageing have been demonstrated before,” says co-author Dr Biswapriya Biswavas Misra, of Wake Forest School of Medicine, Winston-Salem, North Carolina, United States. “However, by pooling the results of previous studies, we revealed a unique immunopathological picture, where the interaction between inflammation, immune function and response to infections forms a clear hallmark of ‘inflamageing’.”
As the study was performed using computer simulations, further experiments in the lab are needed to validate the findings. However, the study shows what researchers can achieve using open-access tools and a little foresight. These results have increased our understanding of ageing and could pave the way for future interventions targeting age-related disease.
Parida, B.P., Misra, B.B., Misra, A.N.: “Visual gene network analysis of aging-specific gene co-expression in human indicates overlaps with immuno-pathological regulations”, 4Open (2018)