Protease activated receptor 2 (PAR2) expression in the myeloid compartment impacts osteoclastogenesis

John Lockhart; Sarah  McGrath; Leif Hultin; Carl Goodyear

doi:10.1136/annrheumdis-2018-EWRR2018.43

Abstract

Introduction: Protease activated receptor 2 (PAR2) is a G protein coupled receptor responsive to serine proteases, which plays a key role in inflammation and pain reception. Rheumatoid arthritis (RA) patients have up-regulated surface expression of PAR2 in circulating monocytes which correlates with disease activity. We have previously demonstrated that Par2 -/- mice are protected from inflammation, bone erosion, and cartilage destruction in a Freund’s Complete Adjuvant (FCA) induced arthritis model. However, it is unclear how PAR2 affects the composition of the myeloid compartment and osteoclastogenesis.

Objectives: The aim of this study was to evaluate the impact of loss of PAR2 on the myeloid compartment and osteoclastogenesis.

Methods: Bone marrow (BM) from 6–10 week old Par2 -/- and control C57BL/6 mice was cultured in pro-osteoclastogenic media for 5 days and the generated mature osteoclasts, tartrate-resistant acid phosphatase positive (TRAP) multinucleated cells, were counted. The resorption potential of these cells was assessed using osteolysis plates and the total osteo-resorption quantified after 7–14 days of culture. BM was also collected for flow cytometric analysis of the haematopoietic cellular composition (with the following markers: CD3, B220, CD11b, Ly6C, Ly6G, CD115, and CD117) and assessed for osteoclast precursors.

Results: In vitro osteoclastogenesis revealed an increase in numbers of mature osteoclasts from Par2 -/- BM compared to WT, corresponding with increased levels of resorption. Flow cytometry of BM from both WT and Par2 -/- mice showed 3 distinct monocyte populations defined by the cell surface expression levels of CD11b and Ly6C. The overall ratio of these populations was not altered in Par2 -/- animals.

Conclusions: BM from Par2 -/- mice has increased osteoclastogenic potential and overall resorptive activity. We propose that this is not due to differences in bone marrow residing osteoclast pre-cursor numbers. This study indicates a potential role for PAR2 in osteoclast differentiation and bone remodelling.

Original language	English
Article number	P018
Pages (from-to)	A21
Number of pages	1
Journal	Annals of the Rheumatic Diseases
Volume	77
Issue number	Supplement 1
DOIs	https://doi.org/10.1136/annrheumdis-2018-EWRR2018.43
Publication status	Published - 21 Feb 2018
Event	European Workshop for Rheumatology Research - Geneva, Switzerland Duration: 22 Feb 2018 → 24 Feb 2018 Conference number: 38

Keywords

PAR2
Osteoarthritis
Medical Research Scotland
Osteoclasts
myeloid

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10.1136/annrheumdis-2018-EWRR2018.43

Glasgow academics awarded grant to research new treatments for osteoarthritis
Lockhart, J.
1/03/13
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£1.2m grant for Osteoarthritis research
Lockhart, J.
1/01/13
1 item of Media coverage
Press/Media: Research
£1.2m to research new treatments for Osteoarthritis
Lockhart, J.
1/01/13
1 item of Media coverage
Press/Media: Research

Cite this

@article{7a6041d3b8ac49d3b6311030e63c876b,

title = "Protease activated receptor 2 (PAR2) expression in the myeloid compartment impacts osteoclastogenesis",

abstract = "Introduction: Protease activated receptor 2 (PAR2) is a G protein coupled receptor responsive to serine proteases, which plays a key role in inflammation and pain reception. Rheumatoid arthritis (RA) patients have up-regulated surface expression of PAR2 in circulating monocytes which correlates with disease activity. We have previously demonstrated that Par2 -/- mice are protected from inflammation, bone erosion, and cartilage destruction in a Freund{\textquoteright}s Complete Adjuvant (FCA) induced arthritis model. However, it is unclear how PAR2 affects the composition of the myeloid compartment and osteoclastogenesis. Objectives: The aim of this study was to evaluate the impact of loss of PAR2 on the myeloid compartment and osteoclastogenesis. Methods: Bone marrow (BM) from 6–10 week old Par2 -/- and control C57BL/6 mice was cultured in pro-osteoclastogenic media for 5 days and the generated mature osteoclasts, tartrate-resistant acid phosphatase positive (TRAP) multinucleated cells, were counted. The resorption potential of these cells was assessed using osteolysis plates and the total osteo-resorption quantified after 7–14 days of culture. BM was also collected for flow cytometric analysis of the haematopoietic cellular composition (with the following markers: CD3, B220, CD11b, Ly6C, Ly6G, CD115, and CD117) and assessed for osteoclast precursors. Results: In vitro osteoclastogenesis revealed an increase in numbers of mature osteoclasts from Par2 -/- BM compared to WT, corresponding with increased levels of resorption. Flow cytometry of BM from both WT and Par2 -/- mice showed 3 distinct monocyte populations defined by the cell surface expression levels of CD11b and Ly6C. The overall ratio of these populations was not altered in Par2 -/- animals. Conclusions: BM from Par2 -/- mice has increased osteoclastogenic potential and overall resorptive activity. We propose that this is not due to differences in bone marrow residing osteoclast pre-cursor numbers. This study indicates a potential role for PAR2 in osteoclast differentiation and bone remodelling.",

keywords = "PAR2, Osteoarthritis, Medical Research Scotland, Osteoclasts, myeloid",

author = "John Lockhart and Sarah McGrath and Leif Hultin and Carl Goodyear",

year = "2018",

month = feb,

day = "21",

doi = "10.1136/annrheumdis-2018-EWRR2018.43",

language = "English",

volume = "77",

pages = "A21",

journal = "Annals of the Rheumatic Diseases",

issn = "0003-4967",

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note = "European Workshop for Rheumatology Research, EWRR 2018 ; Conference date: 22-02-2018 Through 24-02-2018",

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TY - JOUR

T1 - Protease activated receptor 2 (PAR2) expression in the myeloid compartment impacts osteoclastogenesis

AU - Lockhart, John

AU - McGrath, Sarah

AU - Hultin, Leif

AU - Goodyear, Carl

N1 - Conference code: 38

PY - 2018/2/21

Y1 - 2018/2/21

N2 - Introduction: Protease activated receptor 2 (PAR2) is a G protein coupled receptor responsive to serine proteases, which plays a key role in inflammation and pain reception. Rheumatoid arthritis (RA) patients have up-regulated surface expression of PAR2 in circulating monocytes which correlates with disease activity. We have previously demonstrated that Par2 -/- mice are protected from inflammation, bone erosion, and cartilage destruction in a Freund’s Complete Adjuvant (FCA) induced arthritis model. However, it is unclear how PAR2 affects the composition of the myeloid compartment and osteoclastogenesis. Objectives: The aim of this study was to evaluate the impact of loss of PAR2 on the myeloid compartment and osteoclastogenesis. Methods: Bone marrow (BM) from 6–10 week old Par2 -/- and control C57BL/6 mice was cultured in pro-osteoclastogenic media for 5 days and the generated mature osteoclasts, tartrate-resistant acid phosphatase positive (TRAP) multinucleated cells, were counted. The resorption potential of these cells was assessed using osteolysis plates and the total osteo-resorption quantified after 7–14 days of culture. BM was also collected for flow cytometric analysis of the haematopoietic cellular composition (with the following markers: CD3, B220, CD11b, Ly6C, Ly6G, CD115, and CD117) and assessed for osteoclast precursors. Results: In vitro osteoclastogenesis revealed an increase in numbers of mature osteoclasts from Par2 -/- BM compared to WT, corresponding with increased levels of resorption. Flow cytometry of BM from both WT and Par2 -/- mice showed 3 distinct monocyte populations defined by the cell surface expression levels of CD11b and Ly6C. The overall ratio of these populations was not altered in Par2 -/- animals. Conclusions: BM from Par2 -/- mice has increased osteoclastogenic potential and overall resorptive activity. We propose that this is not due to differences in bone marrow residing osteoclast pre-cursor numbers. This study indicates a potential role for PAR2 in osteoclast differentiation and bone remodelling.

AB - Introduction: Protease activated receptor 2 (PAR2) is a G protein coupled receptor responsive to serine proteases, which plays a key role in inflammation and pain reception. Rheumatoid arthritis (RA) patients have up-regulated surface expression of PAR2 in circulating monocytes which correlates with disease activity. We have previously demonstrated that Par2 -/- mice are protected from inflammation, bone erosion, and cartilage destruction in a Freund’s Complete Adjuvant (FCA) induced arthritis model. However, it is unclear how PAR2 affects the composition of the myeloid compartment and osteoclastogenesis. Objectives: The aim of this study was to evaluate the impact of loss of PAR2 on the myeloid compartment and osteoclastogenesis. Methods: Bone marrow (BM) from 6–10 week old Par2 -/- and control C57BL/6 mice was cultured in pro-osteoclastogenic media for 5 days and the generated mature osteoclasts, tartrate-resistant acid phosphatase positive (TRAP) multinucleated cells, were counted. The resorption potential of these cells was assessed using osteolysis plates and the total osteo-resorption quantified after 7–14 days of culture. BM was also collected for flow cytometric analysis of the haematopoietic cellular composition (with the following markers: CD3, B220, CD11b, Ly6C, Ly6G, CD115, and CD117) and assessed for osteoclast precursors. Results: In vitro osteoclastogenesis revealed an increase in numbers of mature osteoclasts from Par2 -/- BM compared to WT, corresponding with increased levels of resorption. Flow cytometry of BM from both WT and Par2 -/- mice showed 3 distinct monocyte populations defined by the cell surface expression levels of CD11b and Ly6C. The overall ratio of these populations was not altered in Par2 -/- animals. Conclusions: BM from Par2 -/- mice has increased osteoclastogenic potential and overall resorptive activity. We propose that this is not due to differences in bone marrow residing osteoclast pre-cursor numbers. This study indicates a potential role for PAR2 in osteoclast differentiation and bone remodelling.

KW - PAR2

KW - Osteoarthritis

KW - Medical Research Scotland

KW - Osteoclasts

KW - myeloid

U2 - 10.1136/annrheumdis-2018-EWRR2018.43

DO - 10.1136/annrheumdis-2018-EWRR2018.43

M3 - Meeting Abstract

SN - 0003-4967

VL - 77

SP - A21

JO - Annals of the Rheumatic Diseases

JF - Annals of the Rheumatic Diseases

IS - Supplement 1

M1 - P018

T2 - European Workshop for Rheumatology Research

Y2 - 22 February 2018 through 24 February 2018

ER -

Protease activated receptor 2 (PAR2) expression in the myeloid compartment impacts osteoclastogenesis

Abstract

Keywords

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Glasgow academics awarded grant to research new treatments for osteoarthritis

£1.2m grant for Osteoarthritis research

£1.2m to research new treatments for Osteoarthritis

Cite this