Regulation of collagen synthesis in mouse skin fibroblasts by distinct angiotensin II receptor subtypes.
We examined the possibility of whether angiotensin (Ang) II type 1 (AT1) and type 2 (AT2) receptor stimulation differentially regulates collagen production in mouse skin fibroblasts. Both AT1 and AT2 receptors were expressed in neonatal skin fibroblasts prepared from wild-type mice to a similar degree, and the AT1a receptor was exclusively expressed as opposed to the AT1b receptor. In wild-type fibroblasts, Ang II increased collagen synthesis accompanied by an increase in expression of tissue inhibitor of metalloproteinase (TIMP)-1, and these increases were inhibited by valsartan, an AT1 receptor blocker, but augmented by PD123319, an AT2 receptor antagonist. Ang II decreased basal and IGF-I-induced collagen production and inhibited TIMP-1 expression in neonatal skin fibroblasts prepared from AT1a knockout (KO) mice. These Ang II-mediated inhibitory effects on collagen production and TIMP-1 expression observed in AT1a KO fibroblasts were attenuated by the addition of PD123319 or a tyrosine phosphatase inhibitor, sodium orthovanadate, but not affected by a serine/threonine phosphatase inhibitor, okadaic acid. Moreover, we demonstrated that transfection of a catalytically inactive, dominant negative SHP-1 (Src homology 2-containing protein-tyrosine phosphatase-1) mutant inhibited the Ang II-mediated inhibitory effect on both collagen synthesis and TIMP-1 expression in AT1a KO fibroblasts. These results suggest that AT1a receptor stimulation increases collagen production in skin fibroblasts at least in part due to the inhibition of collagen degradation via the increase in TIMP-1 expression, whereas AT2 receptor stimulation exerts inhibitory effects on TIMP-1 expression, which is mediated at least partially by the activation of SHP-1, thereby possibly inhibiting collagen production.
Min
Li-Juan
LJ
Department of Medical Biochemistry, Ehime University Medical School, Onsen-gun, Ehime 791-0295, Japan.
Cui
Tai-Xing
TX
Yahata
Yoko
Y
Yamasaki
Kenshi
K
Shiuchi
Tetsuya
T
Liu
Hong-Wei
HW
Chen
Rui
R
Li
Jian-Mei
JM
Okumura
Midori
M
Jinno
Toyohisa
T
Wu
Lan
L
Iwai
Masaru
M
Nahmias
Clara
C
Hashimoto
Koji
K
Horiuchi
Masatsugu
M
D000818:Animals; D000831:Animals, Newborn; D002478:Cells, Cultured; D003094:Collagen / Q000235:genetics*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005347:Fibroblasts / Q000166:cytology / Q000502:physiology*; D015870:Gene Expression / Q000187:drug effects / Q000502:physiology; D047908:Intracellular Signaling Peptides and Proteins; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D019319:Okadaic Acid / Q000494:pharmacology; D054645:Protein Phosphatase 1; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases / Q000235:genetics; D044140:Receptor, Angiotensin, Type 1 / Q000235:genetics / Q000378:metabolism*; D044139:Receptor, Angiotensin, Type 2 / Q000378:metabolism*; D012867:Skin / Q000166:cytology; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000235:genetics; D014638:Vanadates / Q000494:pharmacology
D004791:Enzyme Inhibitors; D047908:Intracellular Signaling Peptides and Proteins; D044140:Receptor, Angiotensin, Type 1; D044139:Receptor, Angiotensin, Type 2; D019715:Tissue Inhibitor of Metalloproteinase-1; D019319:Okadaic Acid; D014638:Vanadates; D003094:Collagen; D054645:Protein Phosphatase 1; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases; C509248:Ptpn6 protein, mouse