Expression of Phosphatonin-Related Genes in Sheep, Dog and Horse Kidneys Using Quantitative Reverse Transcriptase PCR.
Authors: Dittmer Keren E, Heathcott Rosemary W, Marshall Jonathan C, Azarpeykan Sara
Journal: Animals : an open access journal from MDPI
Summary
Phosphate regulation in the kidney involves a complex molecular pathway, yet comparative data across species remain limited—a gap this preliminary investigation addressed by measuring expression of nine key genes in the phosphatonin regulatory system across canine, equine and ovine kidneys using quantitative reverse transcriptase PCR. Post-mortem renal tissue from 10 horses, 10 sheep and 8 dogs was analysed for expression of FGFR1IIIc, three sodium-phosphate co-transporters (NPT1, NPT2a and NPT2c), PTH1R, klotho and the vitamin D-metabolising enzymes CYP27B1 and CYP24A1. Dogs demonstrated markedly elevated NPT2a expression relative to horses and sheep, whilst horses and sheep showed greater NPT1 expression; sheep displayed more balanced expression across all three NPT isoforms, and FGFR1IIIc showed minimal variation between species. Notably, klotho displayed unexpected positive correlation with NPT genes in all species, contrasting with the negative relationship observed between FGFR1IIIc and most NPT genes. These species-specific differences in phosphatonin pathway regulation have direct implications for understanding how chronic kidney disease develops differently across equine, canine and ovine patients, highlighting the importance of considering underlying molecular variations when interpreting clinical phosphate handling abnormalities and formulating treatment strategies tailored to each species.
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Practical Takeaways
- •Species-specific differences in phosphate-regulating gene expression must be considered when evaluating chronic kidney disease pathogenesis in horses, dogs, and sheep
- •Gene expression patterns in equine kidneys differ substantially from other species, suggesting equine-specific therapeutic approaches to phosphate regulation may be warranted
- •Further research into the phosphatonin pathway in horses could improve understanding of renal disease mechanisms and inform preventive strategies
Key Findings
- •NPT2a expression was significantly higher in dog kidneys compared to horse and sheep kidneys
- •NPT1 showed greatest expression in horses and sheep, with relatively similar expression across all three NPT types in sheep
- •FGFR1IIIc expression showed negative correlation with NPT genes (except NPT2a in sheep), while NPT genes were positively correlated with each other
- •Klotho demonstrated unexpected positive correlation with NPT genes across all three species, contrasting with established phosphatonin pathway understanding