SP21
THE EXPRESSION OF KEY AUTOPHAGY GENES IS REDUCED IN THE HEARTS OF
URAEMIC RATS
White W, Kieswich J, Harwood S, Yaqoob M
William Harvey Research Institute, Bart’s & The London, Queen Mary School of Medicine &
Dentistry
INTRODUCTION
Autophagy is the process by which cells remove and recycle unwanted structures. This contributes to
cellular homeostasis and serves as an energy source. Autophagy has an important role in ischaemia
protection, the immune response, the regulation of the inflammatory response, and the prevention of
malignant transformation. A decrease in autophagy is central to physiological and pathological aging.
Observational data suggests these processes may be disordered in patients with chronic kidney
disease. We sought to establish whether, and how, autophagy is altered at a transcriptional level in
uraemia.
METHODS
Rats were rendered uraemic using an adenine diet. RNA was purified from these and from age and
sex matched controls and reverse transcribed. Real-time PCR was performed using a commercially
available array of 84 key autophagy-related genes. RNA quality, reverse transcription and PCR
efficiency, and genomic contamination were all assessed prior to data analysis. Fold-change in gene
expression between control and uraemic groups was calculated using the 2 (-∆∆Ct) method.
RESULTS
The expression of 14 genes was ≥ 3 fold down-regulated in the uraemic compared to the control group
(n=3). Key genes involved in autophagy induction Ambra1 and ULK1, autophagy-regulating genes
Cxcr4, Dapk1, NFKB1, Park2, Pink1, Prkaa1, Rgs19, Tgfb1, Tm9sf1 and Tp53, and lysosomal genes
Cln3 and Ctsd, were all ≥ 3 fold down-regulated. All data included in this analysis passed the
stringent quality control measures outlined in the methods section.
CONCLUSION
These preliminary investigations suggest the expression of several key autophagy-related genes may
be reduced in the hearts of uraemic rats. Previous studies have demonstrated that changes in mRNA
levels of autophagy-related genes are associated with changes in autophagy activity. Thus autophagy
may be impaired in chronic kidney disease, and this may be in part responsible for the uraemic
phenotype. Therapies targeted at stimulating autophagy may therefore be of value in the treatment of
pathological processes associated with chronic kidney disease.