Collectin-11 regulates osteoclastogenesis and bone maintenance via a complement-dependent mechanism

M Mark C. Howard (Medical Research Council Centre for Transplantation, Peter Gorer Department of Immunobiology, School of Immunology & Microbial Sciences, King’s College London) C Conrad A. Farrar (Peter Gorer Department of Immunobiology, School of Immunology and Microbial Sciences, King’s College) C Christopher L. Nauser (Medical Research Council Centre for Transplantation, Peter Gorer Department of Immunobiology, School of Immunology & Microbial Sciences, King’s College London) Y Yusun Jeon (Peter Gorer Department of Immunobiology, School of Immunology and Microbial Sciences, King’s College) A Anastasia Polycarpou (Peter Gorer Department of Immunobiology, School of Immunology and Microbial Sciences, King’s College) D Dorota Smolarek (Peter Gorer Department of Immunobiology, School of Immunology and Microbial Sciences, King’s College) R Roseanna Greenlaw (Peter Gorer Department of Immunobiology, School of Immunology and Microbial Sciences, King’s College) M Martyn Foster (Experimental Pathology Consultancy) P Peter Garred (Consultant Laboratory of Molecular Medicine, Department of Clinical Immunology Section 7631, Rigshospitalet, University of Copenhagen) D Daniela A. Vizitiu (Medical Research Council Centre for Transplantation, Peter Gorer Department of Immunobiology, School of Immunology & Microbial Sciences, King’s College London) S Subhankar Mukhopadhyay (Medical Research Council Centre for Transplantation, Peter Gorer Department of Immunobiology, School of Immunology & Microbial Sciences, King’s College London) S Steven H. Sacks (Peter Gorer Department of Immunobiology, School of Immunology and Microbial Sciences, King’s College)

Abstract

The human developmental disorder 3MC syndrome (Malpuech, Michels, Mingarelli, and Carnevale) features skeletal deformities associated with a deficiency of the pattern recognition molecule collectin-11 (CL-11), yet the underlying molecular and cellular mechanisms remain uncertain. Here, we demonstrate that CL-11 deletion alone does not produce skeletal abnormalities in mice; however, combined deficiencies of CL-11 with complement components MASP-2 (lectin pathway), complement factors B, or C3 (alternative pathway amplification) result in marked vertebral bone loss and spinal curvature by 12 wk of age. Ex vivo osteoclast (OCL) differentiation from bone marrow–derived cells of these double-knockout mice was profoundly impaired but was substantially restored by CL-11 supplementation. This dependence on CL-11 and complement was recapitulated in human OCLs derived from induced pluripotent stem cell lines. CL-11 and the membrane attack complex (C5b-9) colocalized to OCLs and their precursors in normal bone from embryonic development through to adulthood. Together, these findings identify CL-11 as a key regulator of osteoclastogenesis and bone homeostasis acting in concert with complement-mediated signaling, and they nominate CL-11 as a potential therapeutic target in conditions involving dysregulated osteoclast function and bone remodeling.

Article Details

Volume / Issue Vol. 123, Issue 10
Published March 10, 2026
ISSN 0027-8424
Publisher National Academy of Sciences

Authors (12)

M

Mark C. Howard

Medical Research Council Centre for Transplantation, Peter Gorer Department of Immunobiology, School of Immunology & Microbial Sciences, King’s College London

C

Conrad A. Farrar

Peter Gorer Department of Immunobiology, School of Immunology and Microbial Sciences, King’s College

C

Christopher L. Nauser

Medical Research Council Centre for Transplantation, Peter Gorer Department of Immunobiology, School of Immunology & Microbial Sciences, King’s College London

Y

Yusun Jeon

Peter Gorer Department of Immunobiology, School of Immunology and Microbial Sciences, King’s College

A

Anastasia Polycarpou

Peter Gorer Department of Immunobiology, School of Immunology and Microbial Sciences, King’s College

D

Dorota Smolarek

Peter Gorer Department of Immunobiology, School of Immunology and Microbial Sciences, King’s College

R

Roseanna Greenlaw

Peter Gorer Department of Immunobiology, School of Immunology and Microbial Sciences, King’s College

M

Martyn Foster

Experimental Pathology Consultancy

P

Peter Garred

Consultant Laboratory of Molecular Medicine, Department of Clinical Immunology Section 7631, Rigshospitalet, University of Copenhagen

D

Daniela A. Vizitiu

Medical Research Council Centre for Transplantation, Peter Gorer Department of Immunobiology, School of Immunology & Microbial Sciences, King’s College London

S

Subhankar Mukhopadhyay

Medical Research Council Centre for Transplantation, Peter Gorer Department of Immunobiology, School of Immunology & Microbial Sciences, King’s College London

S

Steven H. Sacks

Peter Gorer Department of Immunobiology, School of Immunology and Microbial Sciences, King’s College