Neoepitope fragments as biomarkers for different phenotypes of intervertebral disc degeneration

Shangbin Cui; Wenyue Li; Graciosa Q Teixeira; Cornelia Neidlinger-Wilke; Hans-Joachim Wilke; Lisbet Haglund; Hongwei Ouyang; R Geoff Richards; Sibylle Grad; Mauro Alini; Zhen Li

doi:10.1002/jsp2.1215

Neoepitope fragments as biomarkers for different phenotypes of intervertebral disc degeneration

JOR Spine. 2022 Jul 6;5(3):e1215. doi: 10.1002/jsp2.1215. eCollection 2022 Sep.

Authors

Shangbin Cui^{1

2}, Wenyue Li^{1

3}, Graciosa Q Teixeira⁴, Cornelia Neidlinger-Wilke⁴, Hans-Joachim Wilke⁴, Lisbet Haglund⁵, Hongwei Ouyang³, R Geoff Richards^{1

2}, Sibylle Grad¹, Mauro Alini¹, Zhen Li¹

Affiliations

¹ AO Research Institute Davos Davos Switzerland.
² Guangdong Provincial Key Laboratory of Orthopedics and Traumatology The First Affiliated Hospital of Sun Yat-Sen University Guangzhou China.
³ Zhejiang University-University of Edinburgh Institute (ZJU-UoE Institute) Zhejiang University Haining China.
⁴ Institute of Orthopedic Research and Biomechanics, Centre for Trauma Research Ulm (ZTF Ulm) Ulm University Ulm Germany.
⁵ Department of Surgery and Shriners Hospital for Children McGill University Montreal Canada.

Abstract

Background: During the intervertebral disc (IVD) degeneration process, initial degenerative events occur at the extracellular matrix level, with the appearance of neoepitope peptides formed by the cleavage of aggrecan and collagen. This study aims to elucidate the spatial and temporal alterations of aggrecan and collagen neoepitope level during IVD degeneration.

Methods: Bovine caudal IVDs were cultured under four different conditions to mimic different degenerative situations. Samples cultured after 1- or 8-days were collected for analysis. Human IVD samples were obtained from patients diagnosed with lumbar disc herniation (LDH) or adolescent idiopathic scoliosis (AIS). After immunohistochemical (IHC) staining of Aggrecanase Cleaved C-terminus Aggrecan Neoepitope (NB100), MMP Cleaved C-terminus Aggrecan Neoepitope (MMPCC), Collagen Type 1α1 1/4 fragment (C1α1) and Collagenase Cleaved Type I and II Collagen Neoepitope (C1,2C), staining optical density (OD)/area in extracellular matrix (OECM) and pericellular zone (OPCZ) were analyzed. Conditioned media of the bovine IVD was collected to measure protein level of inflammatory cytokines and C1,2C.

Results: For the bovine IVD sections, the aggrecan MMPCC neoepitope was accumulated in nucleus pulposus (NP) and cartilage endplate (EP) regions following mechanical overload in the one strike model after long-term culture; as for the TNF-α induced degeneration, the OECM and OPCZ of collagen C1,2C neoepitope was significantly increased in the outer AF region after long-term culture; moreover, the C1,2C was only detected in conditioned medium from TNF-α injection + Degenerative loading group after 8 days of culture. LDH patients showed higher MMPCC OECM in NP and higher C1,2C OECM in AF region compared with AIS patients.

Conclusions: In summary, aggrecan and collagen neoepitope profiles showed degeneration induction trigger- and region-specific differences in the IVD organ culture models. Different IVD degeneration types are correlated with specific neoepitope expression profiles. These neoepitopes may be helpful as biomarkers of ECM degradation in early IVD degeneration and indicators of different degeneration phenotypes.

Keywords: biomarker; bioreactor; intervertebral disc degeneration; neoepitope; organ culture model.