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Maston LD, Jones DT, Giermakowska W, Resta TC, Ramiro-Diaz J, Howard TA, Jernigan NL, Herbert L, Maurice AA, Gonzalez Bosc LV. Interleukin-6 trans-signaling contributes to chronic hypoxia-induced pulmonary hypertension. Pulm Circ 2018; 8:2045894018780734. [PMID: 29767573 PMCID: PMC6055240 DOI: 10.1177/2045894018780734] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Interleukin-6 (IL-6) is a pleotropic cytokine that signals through the
membrane-bound IL-6 receptor (mIL-6R) to induce anti-inflammatory
(“classic-signaling”) responses. This cytokine also binds to the soluble IL-6R
(sIL-6R) to promote inflammation (“trans-signaling”). mIL-6R expression is
restricted to hepatocytes and immune cells. Activated T cells release sIL-6R
into adjacent tissues to induce trans-signaling. These cellular actions require
the ubiquitously expressed membrane receptor gp130. Reports show that IL-6 is
produced by pulmonary arterial smooth muscle cells (PASMCs) exposed to hypoxia
in culture as well as the medial layer of the pulmonary arteries in mice exposed
to chronic hypoxia (CH), and IL-6 knockout mice are protected from CH-induced
pulmonary hypertension (PH). IL-6 has the potential to contribute to a broad
array of downstream effects, such as cell growth and migration. CH-induced PH is
associated with increased proliferation and migration of PASMCs to previously
non-muscularized vessels of the lung. We tested the hypothesis that IL-6
trans-signaling contributes to CH-induced PH and arterial remodeling. Plasma
levels of sgp130 were significantly decreased in mice exposed to CH (380 mmHg)
for five days compared to normoxic control mice (630 mmHg), while sIL-6R levels
were unchanged. Consistent with our hypothesis, mice that received the IL-6
trans-signaling-specific inhibitor sgp130Fc, a fusion protein of the soluble
extracellular portion of gp130 with the constant portion of the mouse IgG1
antibody, showed attenuation of CH-induced increases in right ventricular
systolic pressure, right ventricular and pulmonary arterial remodeling as
compared to vehicle (saline)-treated control mice. In addition, PASMCs cultured
in the presence of IL-6 and sIL-6R showed enhanced migration but not
proliferation compared to those treated with IL-6 or sIL-6R alone or in the
presence of sgp130Fc. These results indicate that IL-6 trans-signaling
contributes to pulmonary arterial cell migration and CH-induced PH.
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Affiliation(s)
- Levi D Maston
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - David T Jones
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Wieslawa Giermakowska
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Thomas C Resta
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Juan Ramiro-Diaz
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Tamara A Howard
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Nikki L Jernigan
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Lindsay Herbert
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Anna A Maurice
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Laura V Gonzalez Bosc
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
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