Toll-like receptor 4 (TLR4) impairs nitric oxide contributing to Angiotensin II-induced cavernosal dysfunction

Kenia P. Nunes, Gisele F. Bomfim, Haroldo Alfredo Flores Toque, Theodora Szasz, R Clinton Webb

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Aim Angiotensin II (AngII), a corpus cavernosum (CC) constrictor peptide, modulates Toll like receptor (TLR) expression, a key element of the innate immune system, contributing to impaired vascular function in pathological conditions. However, it is unknown whether TLR4 is involved in AngII-induced erectile dysfunction. In this study, we investigated whether TLR4 plays a role in cavernosal dysfunction caused by AngII upregulation. Material and methods Cavernosal smooth muscle cells (CSMC) from C57/BL6 mice were treated with AngII (0.1 μM) or bacterial LPS (50 ng/ml) for 12–24 h and TLR4 expression was assessed. Mice were infused with AngII (90 ng/min, 28 days) and treated with anti-TLR4 antibody (0.1 mg/daily, i.p.) for the last 14 days of the treatment. CC tissue was used for functional studies and for Western blotting. Nitric Oxide Synthase (NOS) activity was measured by conversion of [3H]-L-arginine to [3H]-L-citrulline, systemic TNF-α levels by ELISA, and reactive oxygen species (ROS) by immunofluorescence. Key findings We report upregulation of TLR4 in CSMC following AngII or LPS stimulation. In AngII-infused mice, chronic treatment with anti-TLR4 antibody (28 ± 2.1%) attenuates adrenergic CC contraction, which also ameliorates nitrergic (68.90 ± 0.21 vs. 51.07 ± 0.63, 8 Hz, AngII-infused mice treated vs. non-treated). Decreased endothelial NOS expression, reduced NOS activity, and augmented levels of TNF-α, and ROS were found following AngII-infusion. These alterations were prevented, or at least decreased by anti-TLR4 antibody treatment. Significance Inhibition of TLR4 ameliorates AngII-impaired cavernosal relaxation, decreases TNF-α levels, and restores NO bioavailability, demonstrating that TLR4 partly mediates AngII-induced cavernosal dysfunction.

Original languageEnglish (US)
Pages (from-to)219-226
Number of pages8
JournalLife sciences
Volume191
DOIs
StatePublished - Dec 15 2017

Fingerprint

Toll-Like Receptor 4
Angiotensin II
Nitric Oxide
Nitric Oxide Synthase
Smooth Muscle Myocytes
Muscle
Antibodies
Reactive Oxygen Species
Up-Regulation
Citrulline
Nitric Oxide Synthase Type III
Immune system
Toll-Like Receptors
Erectile Dysfunction
Adrenergic Agents
Biological Availability
Fluorescent Antibody Technique
Blood Vessels
Arginine
Immune System

Keywords

  • Angiotensin-II
  • Nitric oxide
  • TLR4
  • TNF-α

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Pharmacology, Toxicology and Pharmaceutics(all)

Cite this

Toll-like receptor 4 (TLR4) impairs nitric oxide contributing to Angiotensin II-induced cavernosal dysfunction. / Nunes, Kenia P.; Bomfim, Gisele F.; Flores Toque, Haroldo Alfredo; Szasz, Theodora; Webb, R Clinton.

In: Life sciences, Vol. 191, 15.12.2017, p. 219-226.

Research output: Contribution to journalArticle

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abstract = "Aim Angiotensin II (AngII), a corpus cavernosum (CC) constrictor peptide, modulates Toll like receptor (TLR) expression, a key element of the innate immune system, contributing to impaired vascular function in pathological conditions. However, it is unknown whether TLR4 is involved in AngII-induced erectile dysfunction. In this study, we investigated whether TLR4 plays a role in cavernosal dysfunction caused by AngII upregulation. Material and methods Cavernosal smooth muscle cells (CSMC) from C57/BL6 mice were treated with AngII (0.1 μM) or bacterial LPS (50 ng/ml) for 12–24 h and TLR4 expression was assessed. Mice were infused with AngII (90 ng/min, 28 days) and treated with anti-TLR4 antibody (0.1 mg/daily, i.p.) for the last 14 days of the treatment. CC tissue was used for functional studies and for Western blotting. Nitric Oxide Synthase (NOS) activity was measured by conversion of [3H]-L-arginine to [3H]-L-citrulline, systemic TNF-α levels by ELISA, and reactive oxygen species (ROS) by immunofluorescence. Key findings We report upregulation of TLR4 in CSMC following AngII or LPS stimulation. In AngII-infused mice, chronic treatment with anti-TLR4 antibody (28 ± 2.1{\%}) attenuates adrenergic CC contraction, which also ameliorates nitrergic (68.90 ± 0.21 vs. 51.07 ± 0.63, 8 Hz, AngII-infused mice treated vs. non-treated). Decreased endothelial NOS expression, reduced NOS activity, and augmented levels of TNF-α, and ROS were found following AngII-infusion. These alterations were prevented, or at least decreased by anti-TLR4 antibody treatment. Significance Inhibition of TLR4 ameliorates AngII-impaired cavernosal relaxation, decreases TNF-α levels, and restores NO bioavailability, demonstrating that TLR4 partly mediates AngII-induced cavernosal dysfunction.",
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T1 - Toll-like receptor 4 (TLR4) impairs nitric oxide contributing to Angiotensin II-induced cavernosal dysfunction

AU - Nunes, Kenia P.

AU - Bomfim, Gisele F.

AU - Flores Toque, Haroldo Alfredo

AU - Szasz, Theodora

AU - Webb, R Clinton

PY - 2017/12/15

Y1 - 2017/12/15

N2 - Aim Angiotensin II (AngII), a corpus cavernosum (CC) constrictor peptide, modulates Toll like receptor (TLR) expression, a key element of the innate immune system, contributing to impaired vascular function in pathological conditions. However, it is unknown whether TLR4 is involved in AngII-induced erectile dysfunction. In this study, we investigated whether TLR4 plays a role in cavernosal dysfunction caused by AngII upregulation. Material and methods Cavernosal smooth muscle cells (CSMC) from C57/BL6 mice were treated with AngII (0.1 μM) or bacterial LPS (50 ng/ml) for 12–24 h and TLR4 expression was assessed. Mice were infused with AngII (90 ng/min, 28 days) and treated with anti-TLR4 antibody (0.1 mg/daily, i.p.) for the last 14 days of the treatment. CC tissue was used for functional studies and for Western blotting. Nitric Oxide Synthase (NOS) activity was measured by conversion of [3H]-L-arginine to [3H]-L-citrulline, systemic TNF-α levels by ELISA, and reactive oxygen species (ROS) by immunofluorescence. Key findings We report upregulation of TLR4 in CSMC following AngII or LPS stimulation. In AngII-infused mice, chronic treatment with anti-TLR4 antibody (28 ± 2.1%) attenuates adrenergic CC contraction, which also ameliorates nitrergic (68.90 ± 0.21 vs. 51.07 ± 0.63, 8 Hz, AngII-infused mice treated vs. non-treated). Decreased endothelial NOS expression, reduced NOS activity, and augmented levels of TNF-α, and ROS were found following AngII-infusion. These alterations were prevented, or at least decreased by anti-TLR4 antibody treatment. Significance Inhibition of TLR4 ameliorates AngII-impaired cavernosal relaxation, decreases TNF-α levels, and restores NO bioavailability, demonstrating that TLR4 partly mediates AngII-induced cavernosal dysfunction.

AB - Aim Angiotensin II (AngII), a corpus cavernosum (CC) constrictor peptide, modulates Toll like receptor (TLR) expression, a key element of the innate immune system, contributing to impaired vascular function in pathological conditions. However, it is unknown whether TLR4 is involved in AngII-induced erectile dysfunction. In this study, we investigated whether TLR4 plays a role in cavernosal dysfunction caused by AngII upregulation. Material and methods Cavernosal smooth muscle cells (CSMC) from C57/BL6 mice were treated with AngII (0.1 μM) or bacterial LPS (50 ng/ml) for 12–24 h and TLR4 expression was assessed. Mice were infused with AngII (90 ng/min, 28 days) and treated with anti-TLR4 antibody (0.1 mg/daily, i.p.) for the last 14 days of the treatment. CC tissue was used for functional studies and for Western blotting. Nitric Oxide Synthase (NOS) activity was measured by conversion of [3H]-L-arginine to [3H]-L-citrulline, systemic TNF-α levels by ELISA, and reactive oxygen species (ROS) by immunofluorescence. Key findings We report upregulation of TLR4 in CSMC following AngII or LPS stimulation. In AngII-infused mice, chronic treatment with anti-TLR4 antibody (28 ± 2.1%) attenuates adrenergic CC contraction, which also ameliorates nitrergic (68.90 ± 0.21 vs. 51.07 ± 0.63, 8 Hz, AngII-infused mice treated vs. non-treated). Decreased endothelial NOS expression, reduced NOS activity, and augmented levels of TNF-α, and ROS were found following AngII-infusion. These alterations were prevented, or at least decreased by anti-TLR4 antibody treatment. Significance Inhibition of TLR4 ameliorates AngII-impaired cavernosal relaxation, decreases TNF-α levels, and restores NO bioavailability, demonstrating that TLR4 partly mediates AngII-induced cavernosal dysfunction.

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