Recent results in our laboratories have revealed a new and unexpected relationship between the complement system and post-menopausal bone loss, which has the potential to lead to new therapies for osteoporosis. These studies revealed that mice lacking the C3 component of the complement system were protected from bone loss after ovariectomy (OVX), as shown by micro-computed tomography (microCT) analysis. Our in vitro studies revealed that bone marrow cells from complement receptor-deficient mice had decreased capacity to differentiate into functional osteoclasts. Further, inhibition of complement signaling suppressed human osteoclast differentiation from hematopoietic progenitors. Based on these results, it is hypothesized that the complement system is a key regulator of bone balance and a potential target for the treatment of osteoporosis. To address this hypothesis, two Aims are proposed.
Aim 1 will examine which complement activation pathway is involved, and how complement and complement receptor deficiency impact in vivo bone turnover by assessing bone structure in several OVXed complement knockout mice (Factor D-/-, C1q-/-, MBL-/-, C3-/-, C3aR-/- ,C5aR-/-, and C3aR-/-C5aR-/-) and wild type (WT) controls; microCT and bone histomorphometry will be the primary readouts.
Aim 1 also will examine the role of local complement production in the regulation of bone balance using cross-implantation studies where mesenchymal stem cells (MSC) form ectopic bone in porous ceramic carriers.
Aim 2 will test the use of complement receptor inhibitors as a means of preventing osteoporosis both in WT mice and humanized mice. WT (C57BL/6) mice, human umbilical cord blood stem cell-implanted NSG (NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ) mice, human MSC-implanted NSG mice, and both human umbilical cord blood stem cell and MSC-implanted NSG mice will be OVXed, treated, and assessed by microCT and bone histomorphometry. A novel aspect of the Aim 1 studies is the use of ectopically formed bone from MSCs isolated from the knockout mice that are then implanted into WT mice, and vice versa, which are then assayed for histomorphometric bone parameters - this allows for determination of the role of local complement deficiency of the MSCs on bone formation and loss, and also probes the effect of complement deficiency in hematopoietic cells when WT MSCs are implanted into the complement knockout mice. The complement receptor antagonists treatment experiments in Aim 2 using WT mice and different humanized mice are the most clinically relevant, and will address the potential of using these inhibitors for treating or preventing osteoporosis in humans. These studies will clarify how diminished complement signaling affects osteoblast and osteoclast differentiation in estrogen deprivation induced bone loss. The long-term goal of these studies is to develop new therapies to treat or prevent osteoporosis.

Public Health Relevance

This project will study the role of complement in regulating bone turnover in osteoporosis, which has the potential of opening up complement as a new target for developing novel, effective therapies against osteoporosis.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Research Project (R01)
Project #
5R01AR061564-04
Application #
8913671
Study Section
Innate Immunity and Inflammation Study Section (III)
Program Officer
Chen, Faye H
Project Start
2012-09-15
Project End
2017-08-31
Budget Start
2015-09-01
Budget End
2017-08-31
Support Year
4
Fiscal Year
2015
Total Cost
Indirect Cost
Name
Cleveland Clinic Lerner
Department
Other Basic Sciences
Type
Schools of Medicine
DUNS #
135781701
City
Cleveland
State
OH
Country
United States
Zip Code
44195
MacKay, Danielle L; Kean, Thomas J; Bernardi, Kristina G et al. (2018) Reduced bone loss in a murine model of postmenopausal osteoporosis lacking complement component 3. J Orthop Res 36:118-128
Enyindah-Asonye, Gospel; Li, Yan; Ruth, Jeffrey H et al. (2017) CD318 is a ligand for CD6. Proc Natl Acad Sci U S A 114:E6912-E6921
Enyindah-Asonye, Gospel; Li, Yan; Xin, Wei et al. (2017) CD6 Receptor Regulates Intestinal Ischemia/Reperfusion-induced Injury by Modulating Natural IgM-producing B1a Cell Self-renewal. J Biol Chem 292:661-671
Zhang, Lingjun; Qiu, Wen; Crooke, Stephen et al. (2017) Development of Autologous C5 Vaccine Nanoparticles to Reduce Intravascular Hemolysis in Vivo. ACS Chem Biol 12:539-547
Li, Yan; Fung, John; Lin, Feng (2016) Local Inhibition of Complement Improves Mesenchymal Stem Cell Viability and Function After Administration. Mol Ther 24:1665-74
Zhang, Lingjun; Bell, Brent A; Yu, Minzhong et al. (2016) Complement anaphylatoxin receptors C3aR and C5aR are required in the pathogenesis of experimental autoimmune uveitis. J Leukoc Biol 99:447-54
Li, Yan; Lu, Lina; Qian, Shiguang et al. (2016) Hepatic Stellate Cells Directly Inhibit B Cells via Programmed Death-Ligand 1. J Immunol 196:1617-25
Li, Yan; Qiu, Wen; Zhang, Lingjun et al. (2016) Painting factor H onto mesenchymal stem cells protects the cells from complement- and neutrophil-mediated damage. Biomaterials 102:209-19
Li, Yan; Kim, Byung-Gyu; Qian, Shiguang et al. (2015) Hepatic Stellate Cells Inhibit T Cells through Active TGF-?1 from a Cell Surface-Bound Latent TGF-?1/GARP Complex. J Immunol 195:2648-56
Li, Yan; Tu, Zhidan; Qian, Shiguang et al. (2014) Myeloid-derived suppressor cells as a potential therapy for experimental autoimmune myasthenia gravis. J Immunol 193:2127-34

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