Intracellular localisation of galectin-3 has a protective role in chondrocyte survival
Résumé
Objective: Although galectin-3 (gal-3) is expressed
during arthritic disorders, the part it plays has never been
described. The aim of the study was to determine the
intracellular roles of gal-3 in chondrocytes and cartilage.
Methods: Following treatment with sodium nitroprusside,
a cell death inducer, intracellular levels of total and
phosphorylated gal-3 were measured by immunoblots in
human osteoarthritic (OA) chondrocytes. Cell viability was
also assessed by the lactate dehydrogenase activity in
conditioned media from OA chondrocytes or from ATDC5
cells transfected with a gal-3-expressing vector. After
generating an OA model by intra-articular injection of
0.5% mono-iodoacetate (MIA), histological evaluation of
articular cartilage and subchondral bone was performed in
wild-type (WT) and gal-3 knockout (KO) mice aged
6 weeks and 4 months.
Results: In vitro experiments demonstrated that intracellular
gal-3 had a protective role in chondrocyte survival,
which involved its phosphorylation. In contrast to 6-weekold
mice, 4-month-old gal-3 KO mice, compared with WT
mice, presented OA-like cartilage modifications. OA
induction via MIA injection in WT mice generated
cartilage lesions similar to those found in gal-3 KO
animals. Moreover, OA induction showed a significant
decrease in subchondral bone surface in the gal-3 KO
mice in contrast to the WT group.
Conclusions: Altogether these findings indicate that
intracellular gal-3 has a beneficial effect in articular cells,
as its absence in KO mice led to cartilage lesions.