Christian M. Nefzger 1,2,3, Thierry Jardé1,3,5, Katja Horvay1,3,5, Akanksha Srivastava4, Fernando J. Rossello1,2, Mirsada Prasko1,3,5, Anja S. Knaupp1,2,3, Jacob M. Paynter1,2,3, Bo Sun1, Jinhua Li1, Ryan Lister4, Helen E. Abud*1,3,5 and Jose M Polo*1,2,3


1) Department of Anatomy and Developmental Biology, Monash University
2) Australian Regenerative Medicine Institute,
 Monash University
3) Development and Stem Cells Program, Monash Biomedicine Discovery Institute
4) ARC Centre of Excellence in Plant Energy Biology, The University of Western Australia
5) Cancer Program, Monash Biomedicine Discovery Institute


Aging is associated with a decline in intestinal function characterised by a reduced capacity to absorb nutrients, susceptibility to infection and old age colitis. Moreover, the incidence of colorectal cancer dramatically increases with age. While age-related changes in Wnt signalling have been implicated to contribute to these changes, alterations in metabolism and the epigenome, detected during ageing of other organs, have only been poorly characterized. To investigate the full repertoire of age associated changes we examined tissue from young (2mth) and old (22mth) mice. Initial characterisation of the aged intestinal epithelium showed significant changes in the cellular composition and increased vulnerability to damage induced by chemotherapeutic agent 5-FU. To study the underlying mechanisms, we developed a novel FACS isolation strategy that allowed us to extract pure ISCs from wild type animals uncompromised by Lgr5 haploinsufficiency. RNA sequencing of ISCs and Paneth cells (a key component of the niche) revealed that the transcriptional signature of young and old ISCs were distinct and largely associated with changes in metabolism, while the signatures of young and old Paneth cells were similar. Epigenome profiling of ISCs revealed age related changes in DNA methylation status associated with key transcription factors that correlated with regulation at the RNA level, implying a causal relationship. Functional experiments demonstrated that purified ISCs from old animals produced less organoid colonies compared to young mice, a phenotype that could be ameliorated by modulation of metabolic state. Overall, our studies show that metabolic and epigenetic age-related changes appear to be key factors that impact on aging of the intestinal epithelium with the potential for therapeutic intervention.


AEB 301