Irsogladine maleate potentiates the effects of nitric oxide on activation of cAMP signalling pathways and suppression of mesangial cell mitogenesis.
OBJECTIVE
Deficiency in nitric oxide (NO) is a major factor leading to deterioration and progression of certain glomerular diseases. Agents enhancing NO availability and potentiality are renoprotective. Irsogladine maleate (IM), an anti-ulcer drug, is reported to improve gastric blood flow via NO-dependent mechanisms. We, therefore, asked whether and how IM interacted with NO on glomerular mesangial cells.


METHODS
Mesangial cells were exposed to IM and NO donors. Activation of cAMP signalling pathways was assessed by intracellular cAMP, phosphorylation of VASP, activation of the cAMP response element (CRE) and expression of CRE-regulated proteins.


RESULTS
IM alone did not affect cell proliferation. However, it greatly enhanced the growth-inhibitory effect of NO donor S-nitroso-N-acetylpenicillamine (SNAP). IM acted synergistically with NO on suppression of mitogen-activated protein kinase activation, induction of gap junction protein connexin43, increase of intracellular cAMP, and phosphorylation of VASP. With the use of the CRE-SEAP-based reporting system, IM and SNAP cooperatively activated cAMP response elements (CRE). A similar activation of cAMP was induced by IM with two different NO donors, the sGC activator Bay 41-2272 and the cGMP analogue 8-bromo-cGMP. The effects of SNAP and IM on cAMP activation were mimicked by phosphodiesterase 3 (PDE3) and PDE4 inhibitors. In addition, IM markedly augmented cytokine-induced expression of iNOS, production of NO and activation of CRE.


CONCLUSIONS
The effects of NO were greatly potentiated by IM through synergistic activation of cAMP pathway. Combined therapy with IM and NO may be developed for certain renal diseases.
Yao
J
J
Department of Molecular Signaling, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Yamanashi, Japan. yao@yamanashi.ac.jp
Zhu
Y
Y
Sun
W
W
Sawada
N
N
Hiramatsu
N
N
Takeda
M
M
Kitamura
M
M
D015105:3',5'-Cyclic-AMP Phosphodiesterases / Q000037:antagonists & inhibitors; D000818:Animals; D000897:Anti-Ulcer Agents / Q000494:pharmacology*; D049109:Cell Proliferation / Q000187:drug effects; D018031:Connexin 43 / Q000502:physiology; D000242:Cyclic AMP / Q000502:physiology*; D054684:Cyclic Nucleotide Phosphodiesterases, Type 3; D054703:Cyclic Nucleotide Phosphodiesterases, Type 4; D004357:Drug Synergism; D008297:Male; D050527:Mesangial Cells / Q000166:cytology / Q000187:drug effects*; D009569:Nitric Oxide / Q000096:biosynthesis; D020030:Nitric Oxide Donors / Q000494:pharmacology*; D052247:Nitric Oxide Synthase Type II / Q000235:genetics; D010396:Penicillamine / Q000031:analogs & derivatives / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects*; D014227:Triazines / Q000494:pharmacology*
D000897:Anti-Ulcer Agents; D018031:Connexin 43; D020030:Nitric Oxide Donors; C110881:S-nitro-N-acetylpenicillamine; D014227:Triazines; D009569:Nitric Oxide; D000242:Cyclic AMP; D052247:Nitric Oxide Synthase Type II; D015105:3',5'-Cyclic-AMP Phosphodiesterases; D054684:Cyclic Nucleotide Phosphodiesterases, Type 3; D054703:Cyclic Nucleotide Phosphodiesterases, Type 4; D010396:Penicillamine; C041836:irsogladine