Local action of endogenous renal tubular atrial natriuretic peptide.
Up-regulation of atrial natriuretic peptide (ANP) mRNA in the kidneys in several disorders has been demonstrated; however, evidence that ANP synthesized by the kidney exerts a local function has never been produced. Therefore, we investigated whether endogenous ANP could modulate high glucose-stimulated TGF-beta1, collagen type I and nuclear factor-kappaB (NF-kappaB) in NRK-52E cells using transfection of ANP and ANP small interfering RNA (siANP). NRK-52E cells were grown with or without transfection with ANP plasmid; cells were also transfected with ANP siRNA or control siRNA. These cells were then stimulated with a high glucose concentration to modulate ANP, TGF-beta1, collagen type I, NF-kappaB and IkappaB-alpha, and the results showed that ANP, TGF-beta1, collagen type I and NF-kappaB significantly increased in untransfected cells, and the transfection of ANP significantly attenuated high glucose-activated TGF-beta1, collagen I and NF-kappaB expression. ANP siRNA knocked-down ANP but significantly increased TGF-beta1 and collagen I under normal glucose conditions; ANP siRNA decreased IkappaB-alpha but strongly enhanced high glucose-activated TGF-beta1, collagen type I and NF-kappaB. In contrast, medium from ANP-transfected cells attenuated high glucose-activated TGF-beta1 and collagen type I expression in NRK-52E cells transfected with siANP. In conclusion, our results demonstrated that siANP increased activation of TGF-beta1, collagen type I and NF-kappaB in NRK-52E cells under high glucose conditions, and medium from ANP-transfected cells attenuated high glucose-activated TGF-beta1 and collagen type I. This is the first study to demonstrate the auto/paracrine action of endogenous ANP in renal tubular cells on the attenuation of hyperglycemia-activated TGF-beta1 and NF-kappaB expression. J. Cell. Physiol. 219: 776-786, 2009. (c) 2009 Wiley-Liss, Inc.
Lo
Chao-Sheng
CS
Graduate Institute of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
Chen
Chao-Hung
CH
Hsieh
Tusty-Jiuan
TJ
Lin
Kun-Der
KD
Hsiao
Pi-Jung
PJ
Shin
Shyi-Jang
SJ
D000818:Animals; D009320:Atrial Natriuretic Factor / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D002460:Cell Line; D024042:Collagen Type I / Q000235:genetics / Q000378:metabolism; D017077:Culture Media, Conditioned; D017931:DNA Primers / Q000235:genetics; D015870:Gene Expression / Q000187:drug effects; D020868:Gene Silencing; D005947:Glucose / Q000494:pharmacology; D007684:Kidney Tubules / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D051381:Rats; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D014162:Transfection; D053773:Transforming Growth Factor beta1 / Q000235:genetics / Q000378:metabolism
D024042:Collagen Type I; D017077:Culture Media, Conditioned; D017931:DNA Primers; D016328:NF-kappa B; D034741:RNA, Small Interfering; D011994:Recombinant Proteins; D053773:Transforming Growth Factor beta1; C472610:atrial natriuretic peptide, rat; D009320:Atrial Natriuretic Factor; D005947:Glucose