Faculty of Natural Sciences

TY - JOUR

T1 - A top-down approach to uncover the hidden ligandome of low-density lipoprotein receptor-related protein 1 in cartilage

AU - Yamamoto, Kazuhiro

AU - Scavenius, Carsten

AU - Meschis, Maria M.

AU - Gremida, Abdulrahman M.E.

AU - Mogensen, Emilie H.

AU - Thøgersen, Ida B.

AU - Bonelli, Simone

AU - Scilabra, Simone D.

AU - Jensen, Anders

AU - Santamaria, Salvatore

AU - Ahnström, Josefin

AU - Bou-Gharios, George

AU - Enghild, Jan J.

AU - Nagase, Hideaki

N1 - Publisher Copyright: © 2022

PY - 2022/9

Y1 - 2022/9

N2 - The low-density lipoprotein receptor-related protein 1 (LRP1) is a cell-surface receptor ubiquitously expressed in various tissues. It plays tissue-specific roles by mediating endocytosis of a diverse range of extracellular molecules. Dysregulation of LRP1 is involved in multiple conditions including osteoarthritis (OA) but little information is available about the specific profile of direct binding partners of LRP1 (ligandome) for each tissue, which would lead to a better understanding of its role in disease states. Here, we investigated adult articular cartilage where impaired LRP1-mediated endocytosis leads to tissue destruction. We used a top-down approach involving proteomic analysis of the LRP1 interactome in human chondrocytes, direct binding assays using purified LRP1 and ligand candidates, and validation in LRP1-deficient fibroblasts and human chondrocytes, as well as a novel Lrp1 conditional knockout (KO) mouse model. We found that inhibition of LRP1 and ligand interaction results in cell death, alteration of the entire secretome and transcriptional modulations in human chondrocytes. We identified a chondrocyte-specific LRP1 ligandome consisting of more than 50 novel ligand candidates. Surprisingly, 23 previously reported LRP1 ligands were not regulated by LRP1-mediated endocytosis in human chondrocytes. We confirmed direct LRP1 binding of HGFAC, HMGB1, HMGB2, CEMIP, SLIT2, ADAMTS1, TSG6, IGFBP7, SPARC and LIF, correlation between their affinity for LRP1 and the rate of endocytosis, and some of their intracellular localization. Moreover, a conditional LRP1 KO mouse model demonstrated a critical role of LRP1 in regulating the high-affinity ligands in cartilage in vivo. This systematic approach revealed the specificity and the extent of the chondrocyte LRP1 ligandome and identified potential novel therapeutic targets for OA.

AB - The low-density lipoprotein receptor-related protein 1 (LRP1) is a cell-surface receptor ubiquitously expressed in various tissues. It plays tissue-specific roles by mediating endocytosis of a diverse range of extracellular molecules. Dysregulation of LRP1 is involved in multiple conditions including osteoarthritis (OA) but little information is available about the specific profile of direct binding partners of LRP1 (ligandome) for each tissue, which would lead to a better understanding of its role in disease states. Here, we investigated adult articular cartilage where impaired LRP1-mediated endocytosis leads to tissue destruction. We used a top-down approach involving proteomic analysis of the LRP1 interactome in human chondrocytes, direct binding assays using purified LRP1 and ligand candidates, and validation in LRP1-deficient fibroblasts and human chondrocytes, as well as a novel Lrp1 conditional knockout (KO) mouse model. We found that inhibition of LRP1 and ligand interaction results in cell death, alteration of the entire secretome and transcriptional modulations in human chondrocytes. We identified a chondrocyte-specific LRP1 ligandome consisting of more than 50 novel ligand candidates. Surprisingly, 23 previously reported LRP1 ligands were not regulated by LRP1-mediated endocytosis in human chondrocytes. We confirmed direct LRP1 binding of HGFAC, HMGB1, HMGB2, CEMIP, SLIT2, ADAMTS1, TSG6, IGFBP7, SPARC and LIF, correlation between their affinity for LRP1 and the rate of endocytosis, and some of their intracellular localization. Moreover, a conditional LRP1 KO mouse model demonstrated a critical role of LRP1 in regulating the high-affinity ligands in cartilage in vivo. This systematic approach revealed the specificity and the extent of the chondrocyte LRP1 ligandome and identified potential novel therapeutic targets for OA.

KW - Cartilage

KW - Chondrocyte

KW - Endocytosis

KW - Extracellular matrix

KW - Interactome

KW - LRP1

KW - Osteoarthritis

UR - http://www.scopus.com/inward/record.url?scp=85137616621&partnerID=8YFLogxK

U2 - 10.1016/j.matbio.2022.08.007

DO - 10.1016/j.matbio.2022.08.007

M3 - Journal article

C2 - 36028175

AN - SCOPUS:85137616621

VL - 112

SP - 190

EP - 218

JO - Matrix Biology

JF - Matrix Biology

SN - 0945-053X

ER -