Authors

Young Jong Ko, 1 , 2 , Hong Moon Sohn, 1 , 2 ,Yuria Jang, 1 , 2 Mineon Park, 1 , 2 Bora Kim, 1 , 2 Beomchang Kim, 1 , 2 Jae‐Il Park, 3 Hoon Hyun, 4 Byeongseok Jeong, 5 Chansik Hong, 5 and Wonbong Limcorresponding author 1 , 2 , 6

Affiliations

1 Laboratory of Orthopaedic Research, Chosun University Hospital, Dong‐Gu Gwangju, Republic of Korea,
2 Department of Orthopaedic Surgery, Chosun University Hospital, Dong‐Gu Gwangju, Republic of Korea,
3 Korea Basic Science Institute, Gwangju Center at Chonnam National University, Gwangju Republic of Korea,
4 Department of Biomedical Sciences Chonnam National University Medical School, Gwangju Republic of Korea,
5 Department of Physiology, School of Medicine, Chosun University, Gwangju Republic of Korea,
6 Department of Premedical Science, College of Medicine, Chosun University, Dong‐Gu Gwangju, Republic of Korea,

Topic

Calcium Imaging, Immunology, Medical Research

Abstract

Background
The discovery of receptor activator of nuclear factor‐ĸB ligand (RANKL) as the final effector in the pathogenesis of osteoporosis has led to a better understanding of bone remodeling. When RANKL binds to its receptor (RANK), osteoclastic differentiation and activation are initiated. Herein, we propose a strategy using a novel RANKL variant as a competitive inhibitor for RANKL. The RANKL variant activates LGR4 signaling, which competitively regulates RANK and acts as an immunogen that induces anti‐RANKL antibody production.

Methods
We modified the RANK‐binding site on RANKL using minimal amino acid changes in the RANKL complex and its counterpart receptor RANK and tried to evaluate the inhibitory effects on osteoclastogenesis.

Results
The novel RANKL variant did not bind RANK in osteoclast progenitor cells, but activated LGR4 through the GSK3‐β signaling pathway, thereby suppressing activated T cell cytoplasmic nuclear factor calcineurin‐dependent 1 (NFATc1) expression and activity during osteoclastogenesis. Our RANKL variant generated high levels of RANKL‐specific antibodies, blocked osteoclastogenesis, and inhibited osteoporosis in ovariectomized mouse models. Generated anti‐RANKL antibodies showed a high inhibitory effect on osteoclastogenesis in vivo and in vitro.

Conclusions
We observed that the novel RANKL indeed blocks RANKL via LGR4 signaling and generates anti‐RANKL antibodies, demonstrating an innovative strategy in the development of general immunotherapy.

DOI: https://dx.doi.org/10.1002%2Fctm2.368

Extract

Fluorescence was measured at 340/380 nm dual excitation and 510 nm emission using a pE‐340 Fura illuminator (CoolLED, UK).

Product Associated Features

The 340 nm and 380 nm LED illumination system provides the optimum excitation wavelengths for Fura-2-based calcium imaging, allowing high-precision, stable, high-throughput imaging with video-rate time resolution.

Product Type

pE-340fura

Journal

Clin. Transl. Med.

Year of Publication

2021

Country of Publication

South Korea