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Transactivation of ErbB Family of Receptor Tyrosine Kinases Is Inhibited by Angiotensin-(1-7) via Its Mas Receptor.

Akhtar S, Chandrasekhar B, Attur S, Dhaunsi GS, Yousif MH, Benter IF - PLoS ONE (2015)

Bottom Line: In VSMCs cultured in high glucose (25 mM), Ang-(1-7) inhibited src-dependent ErbB2 transactivation that was opposed by the selective Mas receptor antagonist, D-Pro7-Ang-(1-7).Ang-(1-7) via Mas receptor also inhibited both Angiotensin II- and noradrenaline/norephinephrine-induced transactivation of ErbB2 and/or EGFR receptors.Further, hyperglycemia-induced transactivation of ErbB3 and ErbB4 receptors could be attenuated by Ang-(1-7) that could be prevented by D-Pro7-Ang-(1-7) in VSMC.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmacology and Toxicology, Faculty of Medicine, Kuwait University, Safat 13110, Kuwait.

ABSTRACT
Transactivation of the epidermal growth factor receptor (EGFR or ErbB) family members, namely EGFR and ErbB2, appears important in the development of diabetes-induced vascular dysfunction. Angiotensin-(1-7) [Ang-(1-7)] can prevent the development of hyperglycemia-induced vascular complications partly through inhibiting EGFR transactivation. Here, we investigated whether Ang-(1-7) can inhibit transactivation of ErbB2 as well as other ErbB receptors in vivo and in vitro. Streptozotocin-induced diabetic rats were chronically treated with Ang-(1-7) or AG825, a selective ErbB2 inhibitor, for 4 weeks and mechanistic studies performed in the isolated mesenteric vasculature bed as well as in cultured vascular smooth muscle cells (VSMCs). Ang-(1-7) or AG825 treatment inhibited diabetes-induced phosphorylation of ErbB2 receptor at tyrosine residues Y1221/22, Y1248, Y877, as well as downstream signaling via ERK1/2, p38 MAPK, ROCK, eNOS and IkB-α in the mesenteric vascular bed. In VSMCs cultured in high glucose (25 mM), Ang-(1-7) inhibited src-dependent ErbB2 transactivation that was opposed by the selective Mas receptor antagonist, D-Pro7-Ang-(1-7). Ang-(1-7) via Mas receptor also inhibited both Angiotensin II- and noradrenaline/norephinephrine-induced transactivation of ErbB2 and/or EGFR receptors. Further, hyperglycemia-induced transactivation of ErbB3 and ErbB4 receptors could be attenuated by Ang-(1-7) that could be prevented by D-Pro7-Ang-(1-7) in VSMC. These data suggest that Ang-(1-7) via its Mas receptor acts as a pan-ErbB inhibitor and might represent a novel general mechanism by which Ang-(1-7) exerts its beneficial effects in many disease states including diabetes-induced vascular complications.

No MeSH data available.


Related in: MedlinePlus

Ang-(1–7) via its Mas receptor inhibits NE-mediated transactivation of (A) ErbB2 and (B) EGFR receptors in VSMC.In both A) and B) panel (i) is a representative Western blot showing either the levels of total (t-) or phosphorylated (p-) ErbB2 receptor (Y1221/1222) or EGFR (Y1068) and total β-actin in VSMC grown in normal (5.5 mM) D-glucose (NG), or NG treated with NE (10-7M) or NE together with 1 micromolar Ang-(1–7) (+ A(1–7), or A(1–7) together with D-Pro7-Ang-(1–7) (lane labeled as + A(1–7) +D-Pro), AG1478 (1μM) or AG825 (0.1μM) or 1 micromolar Prazosin (labelled as NE 10−7 + PRAZ); Panels ii is the densitometry histogram showing ratio levels of stated phosphorylated to total proteins following normalization of each to actin and presented relative to control. N = 5; Mean ± SD. Asterisk (*) indicates significantly different (p<0.05) mean values from NG whereas hash (#) indicates significantly different mean values (p<0.05) from NG at 10-7M dose.
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pone.0141657.g008: Ang-(1–7) via its Mas receptor inhibits NE-mediated transactivation of (A) ErbB2 and (B) EGFR receptors in VSMC.In both A) and B) panel (i) is a representative Western blot showing either the levels of total (t-) or phosphorylated (p-) ErbB2 receptor (Y1221/1222) or EGFR (Y1068) and total β-actin in VSMC grown in normal (5.5 mM) D-glucose (NG), or NG treated with NE (10-7M) or NE together with 1 micromolar Ang-(1–7) (+ A(1–7), or A(1–7) together with D-Pro7-Ang-(1–7) (lane labeled as + A(1–7) +D-Pro), AG1478 (1μM) or AG825 (0.1μM) or 1 micromolar Prazosin (labelled as NE 10−7 + PRAZ); Panels ii is the densitometry histogram showing ratio levels of stated phosphorylated to total proteins following normalization of each to actin and presented relative to control. N = 5; Mean ± SD. Asterisk (*) indicates significantly different (p<0.05) mean values from NG whereas hash (#) indicates significantly different mean values (p<0.05) from NG at 10-7M dose.

Mentions: We next compared the effects of Ang-(1–7) on NE-mediated transactivation of ErbB2 and EGFR in VSMC. A dose dependent NE-mediated increase in phosphorylation of both ErbB2 and EGFR receptors was observed that was followed by a decrease at higher doses (Fig 7). At the optimal stimulatory concentration of NE (10-7M) for both receptors, NE-induced phosphorylation of ErbB2 and EGFR was blocked by the selective α-1-adrenoceptor antagonist, Prazosin (p<0.05; Fig 7). Furthermore, Ang-(1–7) significantly inhibited NE-mediated phosphorylation of both ErbB2 and EGFR receptors that could be significantly reversed by the selective Mas receptor antagonist, [D-Pro7Angiotensin- (1–7)]. In addition, NE-mediated phosphorylation of ErbB2 and EGFR receptors could be significantly attenuated by AG825 and AG1478 respectively as well as by Prazosin (p<0.05; Fig 8).


Transactivation of ErbB Family of Receptor Tyrosine Kinases Is Inhibited by Angiotensin-(1-7) via Its Mas Receptor.

Akhtar S, Chandrasekhar B, Attur S, Dhaunsi GS, Yousif MH, Benter IF - PLoS ONE (2015)

Ang-(1–7) via its Mas receptor inhibits NE-mediated transactivation of (A) ErbB2 and (B) EGFR receptors in VSMC.In both A) and B) panel (i) is a representative Western blot showing either the levels of total (t-) or phosphorylated (p-) ErbB2 receptor (Y1221/1222) or EGFR (Y1068) and total β-actin in VSMC grown in normal (5.5 mM) D-glucose (NG), or NG treated with NE (10-7M) or NE together with 1 micromolar Ang-(1–7) (+ A(1–7), or A(1–7) together with D-Pro7-Ang-(1–7) (lane labeled as + A(1–7) +D-Pro), AG1478 (1μM) or AG825 (0.1μM) or 1 micromolar Prazosin (labelled as NE 10−7 + PRAZ); Panels ii is the densitometry histogram showing ratio levels of stated phosphorylated to total proteins following normalization of each to actin and presented relative to control. N = 5; Mean ± SD. Asterisk (*) indicates significantly different (p<0.05) mean values from NG whereas hash (#) indicates significantly different mean values (p<0.05) from NG at 10-7M dose.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4633289&req=5

pone.0141657.g008: Ang-(1–7) via its Mas receptor inhibits NE-mediated transactivation of (A) ErbB2 and (B) EGFR receptors in VSMC.In both A) and B) panel (i) is a representative Western blot showing either the levels of total (t-) or phosphorylated (p-) ErbB2 receptor (Y1221/1222) or EGFR (Y1068) and total β-actin in VSMC grown in normal (5.5 mM) D-glucose (NG), or NG treated with NE (10-7M) or NE together with 1 micromolar Ang-(1–7) (+ A(1–7), or A(1–7) together with D-Pro7-Ang-(1–7) (lane labeled as + A(1–7) +D-Pro), AG1478 (1μM) or AG825 (0.1μM) or 1 micromolar Prazosin (labelled as NE 10−7 + PRAZ); Panels ii is the densitometry histogram showing ratio levels of stated phosphorylated to total proteins following normalization of each to actin and presented relative to control. N = 5; Mean ± SD. Asterisk (*) indicates significantly different (p<0.05) mean values from NG whereas hash (#) indicates significantly different mean values (p<0.05) from NG at 10-7M dose.
Mentions: We next compared the effects of Ang-(1–7) on NE-mediated transactivation of ErbB2 and EGFR in VSMC. A dose dependent NE-mediated increase in phosphorylation of both ErbB2 and EGFR receptors was observed that was followed by a decrease at higher doses (Fig 7). At the optimal stimulatory concentration of NE (10-7M) for both receptors, NE-induced phosphorylation of ErbB2 and EGFR was blocked by the selective α-1-adrenoceptor antagonist, Prazosin (p<0.05; Fig 7). Furthermore, Ang-(1–7) significantly inhibited NE-mediated phosphorylation of both ErbB2 and EGFR receptors that could be significantly reversed by the selective Mas receptor antagonist, [D-Pro7Angiotensin- (1–7)]. In addition, NE-mediated phosphorylation of ErbB2 and EGFR receptors could be significantly attenuated by AG825 and AG1478 respectively as well as by Prazosin (p<0.05; Fig 8).

Bottom Line: In VSMCs cultured in high glucose (25 mM), Ang-(1-7) inhibited src-dependent ErbB2 transactivation that was opposed by the selective Mas receptor antagonist, D-Pro7-Ang-(1-7).Ang-(1-7) via Mas receptor also inhibited both Angiotensin II- and noradrenaline/norephinephrine-induced transactivation of ErbB2 and/or EGFR receptors.Further, hyperglycemia-induced transactivation of ErbB3 and ErbB4 receptors could be attenuated by Ang-(1-7) that could be prevented by D-Pro7-Ang-(1-7) in VSMC.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmacology and Toxicology, Faculty of Medicine, Kuwait University, Safat 13110, Kuwait.

ABSTRACT
Transactivation of the epidermal growth factor receptor (EGFR or ErbB) family members, namely EGFR and ErbB2, appears important in the development of diabetes-induced vascular dysfunction. Angiotensin-(1-7) [Ang-(1-7)] can prevent the development of hyperglycemia-induced vascular complications partly through inhibiting EGFR transactivation. Here, we investigated whether Ang-(1-7) can inhibit transactivation of ErbB2 as well as other ErbB receptors in vivo and in vitro. Streptozotocin-induced diabetic rats were chronically treated with Ang-(1-7) or AG825, a selective ErbB2 inhibitor, for 4 weeks and mechanistic studies performed in the isolated mesenteric vasculature bed as well as in cultured vascular smooth muscle cells (VSMCs). Ang-(1-7) or AG825 treatment inhibited diabetes-induced phosphorylation of ErbB2 receptor at tyrosine residues Y1221/22, Y1248, Y877, as well as downstream signaling via ERK1/2, p38 MAPK, ROCK, eNOS and IkB-α in the mesenteric vascular bed. In VSMCs cultured in high glucose (25 mM), Ang-(1-7) inhibited src-dependent ErbB2 transactivation that was opposed by the selective Mas receptor antagonist, D-Pro7-Ang-(1-7). Ang-(1-7) via Mas receptor also inhibited both Angiotensin II- and noradrenaline/norephinephrine-induced transactivation of ErbB2 and/or EGFR receptors. Further, hyperglycemia-induced transactivation of ErbB3 and ErbB4 receptors could be attenuated by Ang-(1-7) that could be prevented by D-Pro7-Ang-(1-7) in VSMC. These data suggest that Ang-(1-7) via its Mas receptor acts as a pan-ErbB inhibitor and might represent a novel general mechanism by which Ang-(1-7) exerts its beneficial effects in many disease states including diabetes-induced vascular complications.

No MeSH data available.


Related in: MedlinePlus