Activated rho kinase mediates diabetes-induced elevation of vascular arginase activation and contributes to impaired corpora cavernosa relaxation: Possible involvement of p38 MAPK activation

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Abstract

Introduction.: Activated RhoA/Rho kinase (ROCK) has been implicated in diabetes-induced erectile dysfunction. Earlier studies have demonstrated involvement of ROCK pathway in the activation of arginase in endothelial cells. However, signaling pathways activated by ROCK in the penis remain unclear. Aim.: We tested whether ROCK and p38 MAPK are involved in the elevation of arginase activity and subsequent impairment of corpora cavernosal (CC) relaxation in diabetes. Methods.: Eight weeks after streptozotocin-induced diabetes, vascular functional studies, arginase activity assay, and protein expression of RhoA, ROCK, phospho-p38 MAPK, p38 MAPK, phospho-MYPT-1Thr850, MYPT-1 and arginase levels were assessed in CC tissues from nondiabetic wild type (WT), diabetic (D) WT (WT+D), partial ROCK 2+/- knockout (KO), and ROCK 2+/- KO+D mice. Main Outcome Measures.: The expression of RhoA, ROCK 1 and 2, phosphorylation of MYPT-1Thr850 and p38 MAPK, arginase activity/expression, endothelial- and nitrergic-dependent relaxation of CC was assayed. Results.: Diabetes significantly reduced maximum relaxation (Emax) to both endothelium-dependent acetylcholine (WT+D: Emax; 61±4% vs. WT: Emax; 75±2%) and nitrergic nerve stimulation. These effects were associated with increased expression of active RhoA, ROCK 2, phospho-MYPT-1Thr850, phospho-p38 MAPK, arginase II, and activity of corporal arginase (1.6-fold) in WT diabetic CC. However, this impairment in CC of WT+D mice was absent in heterozygous ROCK 2+/- KO+D mice for acetylcholine (Emax: 80±5%) and attenuated for nitrergic nerve-induced relaxation. CC of ROCK 2+/- KO+D mice showed much less ROCK activity, did not exhibit p38 MAPK activation, and had reduced arginase activity and arginase II expression. These findings indicate that ROCK 2 mediates diabetes-induced elevation of arginase activity. Additionally, pretreatment of WT diabetic CC with inhibitors of arginase (ABH) or p38 MAPK (SB203580) partially prevented impairment of ACh- and nitrergic nerve-induced relaxation and elevation of arginase activity. Conclusion.: ROCK 2, p38 MAPK and arginase play key roles in diabetes-induced impairment of CC relaxation.

Original languageEnglish (US)
Pages (from-to)1502-1515
Number of pages14
JournalJournal of Sexual Medicine
Volume10
Issue number6
DOIs
StatePublished - Jan 1 2013

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Arginase
rho-Associated Kinases
p38 Mitogen-Activated Protein Kinases
Blood Vessels
Nitrergic Neurons
Knockout Mice
Acetylcholine
rhoA GTP-Binding Protein
Experimental Diabetes Mellitus
Penis
Erectile Dysfunction
Endothelium

Keywords

  • Arginase
  • Diabetes
  • P38 MAPK
  • Rho Kinase

ASJC Scopus subject areas

  • Reproductive Medicine
  • Obstetrics and Gynecology
  • Urology

Cite this

@article{1de8cf7f92c54ea49c5c1ce3d29e2afe,
title = "Activated rho kinase mediates diabetes-induced elevation of vascular arginase activation and contributes to impaired corpora cavernosa relaxation: Possible involvement of p38 MAPK activation",
abstract = "Introduction.: Activated RhoA/Rho kinase (ROCK) has been implicated in diabetes-induced erectile dysfunction. Earlier studies have demonstrated involvement of ROCK pathway in the activation of arginase in endothelial cells. However, signaling pathways activated by ROCK in the penis remain unclear. Aim.: We tested whether ROCK and p38 MAPK are involved in the elevation of arginase activity and subsequent impairment of corpora cavernosal (CC) relaxation in diabetes. Methods.: Eight weeks after streptozotocin-induced diabetes, vascular functional studies, arginase activity assay, and protein expression of RhoA, ROCK, phospho-p38 MAPK, p38 MAPK, phospho-MYPT-1Thr850, MYPT-1 and arginase levels were assessed in CC tissues from nondiabetic wild type (WT), diabetic (D) WT (WT+D), partial ROCK 2+/- knockout (KO), and ROCK 2+/- KO+D mice. Main Outcome Measures.: The expression of RhoA, ROCK 1 and 2, phosphorylation of MYPT-1Thr850 and p38 MAPK, arginase activity/expression, endothelial- and nitrergic-dependent relaxation of CC was assayed. Results.: Diabetes significantly reduced maximum relaxation (Emax) to both endothelium-dependent acetylcholine (WT+D: Emax; 61±4{\%} vs. WT: Emax; 75±2{\%}) and nitrergic nerve stimulation. These effects were associated with increased expression of active RhoA, ROCK 2, phospho-MYPT-1Thr850, phospho-p38 MAPK, arginase II, and activity of corporal arginase (1.6-fold) in WT diabetic CC. However, this impairment in CC of WT+D mice was absent in heterozygous ROCK 2+/- KO+D mice for acetylcholine (Emax: 80±5{\%}) and attenuated for nitrergic nerve-induced relaxation. CC of ROCK 2+/- KO+D mice showed much less ROCK activity, did not exhibit p38 MAPK activation, and had reduced arginase activity and arginase II expression. These findings indicate that ROCK 2 mediates diabetes-induced elevation of arginase activity. Additionally, pretreatment of WT diabetic CC with inhibitors of arginase (ABH) or p38 MAPK (SB203580) partially prevented impairment of ACh- and nitrergic nerve-induced relaxation and elevation of arginase activity. Conclusion.: ROCK 2, p38 MAPK and arginase play key roles in diabetes-induced impairment of CC relaxation.",
keywords = "Arginase, Diabetes, P38 MAPK, Rho Kinase",
author = "{Flores Toque}, {Haroldo Alfredo} and Nunes, {Kenia P.} and Lin Yao and Liao, {James K.} and Webb, {R Clinton} and Caldwell, {Ruth B} and Caldwell, {Robert William}",
year = "2013",
month = "1",
day = "1",
doi = "10.1111/jsm.12134",
language = "English (US)",
volume = "10",
pages = "1502--1515",
journal = "Journal of Sexual Medicine",
issn = "1743-6095",
publisher = "Wiley-Blackwell",
number = "6",

}

TY - JOUR

T1 - Activated rho kinase mediates diabetes-induced elevation of vascular arginase activation and contributes to impaired corpora cavernosa relaxation

T2 - Possible involvement of p38 MAPK activation

AU - Flores Toque, Haroldo Alfredo

AU - Nunes, Kenia P.

AU - Yao, Lin

AU - Liao, James K.

AU - Webb, R Clinton

AU - Caldwell, Ruth B

AU - Caldwell, Robert William

PY - 2013/1/1

Y1 - 2013/1/1

N2 - Introduction.: Activated RhoA/Rho kinase (ROCK) has been implicated in diabetes-induced erectile dysfunction. Earlier studies have demonstrated involvement of ROCK pathway in the activation of arginase in endothelial cells. However, signaling pathways activated by ROCK in the penis remain unclear. Aim.: We tested whether ROCK and p38 MAPK are involved in the elevation of arginase activity and subsequent impairment of corpora cavernosal (CC) relaxation in diabetes. Methods.: Eight weeks after streptozotocin-induced diabetes, vascular functional studies, arginase activity assay, and protein expression of RhoA, ROCK, phospho-p38 MAPK, p38 MAPK, phospho-MYPT-1Thr850, MYPT-1 and arginase levels were assessed in CC tissues from nondiabetic wild type (WT), diabetic (D) WT (WT+D), partial ROCK 2+/- knockout (KO), and ROCK 2+/- KO+D mice. Main Outcome Measures.: The expression of RhoA, ROCK 1 and 2, phosphorylation of MYPT-1Thr850 and p38 MAPK, arginase activity/expression, endothelial- and nitrergic-dependent relaxation of CC was assayed. Results.: Diabetes significantly reduced maximum relaxation (Emax) to both endothelium-dependent acetylcholine (WT+D: Emax; 61±4% vs. WT: Emax; 75±2%) and nitrergic nerve stimulation. These effects were associated with increased expression of active RhoA, ROCK 2, phospho-MYPT-1Thr850, phospho-p38 MAPK, arginase II, and activity of corporal arginase (1.6-fold) in WT diabetic CC. However, this impairment in CC of WT+D mice was absent in heterozygous ROCK 2+/- KO+D mice for acetylcholine (Emax: 80±5%) and attenuated for nitrergic nerve-induced relaxation. CC of ROCK 2+/- KO+D mice showed much less ROCK activity, did not exhibit p38 MAPK activation, and had reduced arginase activity and arginase II expression. These findings indicate that ROCK 2 mediates diabetes-induced elevation of arginase activity. Additionally, pretreatment of WT diabetic CC with inhibitors of arginase (ABH) or p38 MAPK (SB203580) partially prevented impairment of ACh- and nitrergic nerve-induced relaxation and elevation of arginase activity. Conclusion.: ROCK 2, p38 MAPK and arginase play key roles in diabetes-induced impairment of CC relaxation.

AB - Introduction.: Activated RhoA/Rho kinase (ROCK) has been implicated in diabetes-induced erectile dysfunction. Earlier studies have demonstrated involvement of ROCK pathway in the activation of arginase in endothelial cells. However, signaling pathways activated by ROCK in the penis remain unclear. Aim.: We tested whether ROCK and p38 MAPK are involved in the elevation of arginase activity and subsequent impairment of corpora cavernosal (CC) relaxation in diabetes. Methods.: Eight weeks after streptozotocin-induced diabetes, vascular functional studies, arginase activity assay, and protein expression of RhoA, ROCK, phospho-p38 MAPK, p38 MAPK, phospho-MYPT-1Thr850, MYPT-1 and arginase levels were assessed in CC tissues from nondiabetic wild type (WT), diabetic (D) WT (WT+D), partial ROCK 2+/- knockout (KO), and ROCK 2+/- KO+D mice. Main Outcome Measures.: The expression of RhoA, ROCK 1 and 2, phosphorylation of MYPT-1Thr850 and p38 MAPK, arginase activity/expression, endothelial- and nitrergic-dependent relaxation of CC was assayed. Results.: Diabetes significantly reduced maximum relaxation (Emax) to both endothelium-dependent acetylcholine (WT+D: Emax; 61±4% vs. WT: Emax; 75±2%) and nitrergic nerve stimulation. These effects were associated with increased expression of active RhoA, ROCK 2, phospho-MYPT-1Thr850, phospho-p38 MAPK, arginase II, and activity of corporal arginase (1.6-fold) in WT diabetic CC. However, this impairment in CC of WT+D mice was absent in heterozygous ROCK 2+/- KO+D mice for acetylcholine (Emax: 80±5%) and attenuated for nitrergic nerve-induced relaxation. CC of ROCK 2+/- KO+D mice showed much less ROCK activity, did not exhibit p38 MAPK activation, and had reduced arginase activity and arginase II expression. These findings indicate that ROCK 2 mediates diabetes-induced elevation of arginase activity. Additionally, pretreatment of WT diabetic CC with inhibitors of arginase (ABH) or p38 MAPK (SB203580) partially prevented impairment of ACh- and nitrergic nerve-induced relaxation and elevation of arginase activity. Conclusion.: ROCK 2, p38 MAPK and arginase play key roles in diabetes-induced impairment of CC relaxation.

KW - Arginase

KW - Diabetes

KW - P38 MAPK

KW - Rho Kinase

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UR - http://www.scopus.com/inward/citedby.url?scp=84878736457&partnerID=8YFLogxK

U2 - 10.1111/jsm.12134

DO - 10.1111/jsm.12134

M3 - Article

C2 - 23566117

AN - SCOPUS:84878736457

VL - 10

SP - 1502

EP - 1515

JO - Journal of Sexual Medicine

JF - Journal of Sexual Medicine

SN - 1743-6095

IS - 6

ER -