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Abstract: SA-OR030

Dysregulated Translation and Differential p53 Isoform Expression in the Kidney during Diabetes

Session Information

Category: Diabetic Kidney Disease

  • 601 Diabetic Kidney Disease: Basic

Authors

  • Maier, Bernhard, Indiana University School of Medicine, Indianapolis, Indiana, United States
  • Hato, Takashi, Indiana University School of Medicine, Indianapolis, Indiana, United States
  • Sutton, Timothy A., Indiana University School of Medicine, Indianapolis, Indiana, United States
  • Dagher, Pierre C., Indiana University School of Medicine, Indianapolis, Indiana, United States
Background

Over 30 million people in the US have diabetes and it remains the leading cause of ESRD. Critically missing from investigation into the pathogenesis of diabetic nephropathy (DN) is the detailed examination of translation, the fundamental process linking gene expression to the synthesis of functional proteins. In this study we use a mouse model of diabetes to examine differential and sequential changes in global translation as well as expression of p53, an important regulator of transcription and translation during cell stress, in the kidney.

Methods

Transcriptional (RNA-seq) and translational (polysome, Ribo-seq) profiling are used to study changes in the translatome during progression of diabetes in the kidney of db/db (B6.BKS(D)-Lepr db/J) mice. p53 isoform expression is examined by biochemical, proteomic, and translational profiling in db/db mice and nondiabetic background (WT) mice.

Results

Transcriptional profiling reveals that pathways regulating translation are the most differentially altered in the kidney of db/db mice as the diabetic state progresses from 8 weeks to 12 weeks old. Significant changes are observed broadly across ribosomal proteins and regulators of both ribosomal biogenesis and translation. Direct analysis of translation by polysome profiling demonstrates translational activity is increased by 50% in 12 week-old compared to 8 week-old db/db mice. In addition, Ribo-seq confirms the increase in translational activity in the kidney from db/db mice as compared to WT mice. Further analysis of Ribo-seq data reveals four general variations of ribosomal kinetics in the kidney of db/db mice as compared to WT mice. Given the relationship between cell stress and altered translation, we examined p53 isoform expression in the kidney of db/db mice. Immunoblotting reveals the presence of a ~44kDa band consistent with ΔNp53, a translationally-regulated (IRES-mediated) p53 isoform modulating aging and metabolism, in the kidney of db/db mice that is absent in WT mice. Proteomic analysis and ribosome footprint profiling (Ribo-seq), an indispensable method to examine IRES-mediated generation of proteins, further substantiate the differential generation of ΔNp53 in the kidney of db/db mice.

Conclusion

Dysregulated translation in the diabetic state is associated with ΔNp53 expression that can in turn alter translation and contribute to DN.

Funding

  • NIDDK Support