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  • Role of 2',3'-cyclic nucleotide 3'-phosphodiesterase in the renal 2',3'-cAMP-adenosine pathway.

Role of 2',3'-cyclic nucleotide 3'-phosphodiesterase in the renal 2',3'-cAMP-adenosine pathway.

American journal of physiology. Renal physiology (2014-05-09)
Edwin K Jackson, Delbert G Gillespie, Zaichuan Mi, Dongmei Cheng, Rashmi Bansal, Keri Janesko-Feldman, Patrick M Kochanek
ABSTRACT

Energy depletion increases the renal production of 2',3'-cAMP (a positional isomer of 3',5'-cAMP that opens mitochondrial permeability transition pores) and 2',3'-cAMP is converted to 2'-AMP and 3'-AMP, which in turn are metabolized to adenosine. Because the enzymes involved in this "2',3'-cAMP-adenosine pathway" are unknown, we examined whether 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNPase) participates in the renal metabolism of 2',3'-cAMP. Western blotting and real-time PCR demonstrated expression of CNPase in rat glomerular mesangial, preglomerular vascular smooth muscle and endothelial, proximal tubular, thick ascending limb and collecting duct cells. Real-time PCR established the expression of CNPase in human glomerular mesangial, proximal tubular and vascular smooth muscle cells; and the level of expression of CNPase was greater than that for phosphodiesterase 4 (major enzyme for the metabolism of 3',5'-cAMP). Overexpression of CNPase in rat preglomerular vascular smooth muscle cells increased the metabolism of exogenous 2',3'-cAMP to 2'-AMP. Infusions of 2',3'-cAMP into isolated CNPase wild-type (+/+) kidneys increased renal venous 2'-AMP, and this response was diminished by 63% in CNPase knockout (-/-) kidneys, whereas the conversion of 3',5'-cAMP to 5'-AMP was similar in CNPase +/+ vs. -/- kidneys. In CNPase +/+ kidneys, energy depletion (metabolic poisons) increased kidney tissue levels of adenosine and its metabolites (inosine, hypoxanthine, xanthine, and uric acid) without accumulation of 2',3'-cAMP. In contrast, in CNPase -/- kidneys, energy depletion increased kidney tissue levels of 2',3'-cAMP and abolished the increase in adenosine and its metabolites. In conclusion, kidneys express CNPase, and renal CNPase mediates in part the renal 2',3'-cAMP-adenosine pathway.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Adenosine
Supelco
Adenosine, Pharmaceutical Secondary Standard; Certified Reference Material
Sigma-Aldrich
Adenosine, ≥99%
Sigma-Aldrich
Adenosine, suitable for cell culture, BioReagent
Sigma-Aldrich
Adenosine 3′,5′-cyclic monophosphate, ≥98.5% (HPLC), powder
Sigma-Aldrich
Adenosine 2′(3′)-monophosphate mixed isomers
Adenosine, European Pharmacopoeia (EP) Reference Standard
Sigma-Aldrich
Adenosine 3′,5′-cyclic monophosphate sodium salt monohydrate, ≥98.0% (HPLC), powder