Differential expression of galectin‐1 and its interactions with cells and laminins in the intervertebral disc

Abstract

Galectin-1 (Gal-1), an endogenous β-galactoside-binding protein, binds to laminins, which are highly expressed in the nucleus pulposus (NP) of the intervertebral disc (IVD). The objective of this study is to evaluate the expression of Gal-1 protein in IVD tissues during aging and the effect of Gal-1 on IVD cell adhesion to laminins. Tissues from rat, porcine and human (scoliosis or disc degeneration) IVDs were used to evaluate Gal-1 expression via immunostaining, RT-PCR and Western Blot analysis. Attachment of isolated IVD cells (porcine and human) on select laminin isoforms (LM-111 and LM-511) was compared with/without pre-incubation with exogenous Gal-1. A biotinylated Gal-1(B-Gal-1) was used to evaluate for binding to IVD cells and to select for IVD cells by magnetic activated cell sorting (MACS). NP cells expressed high levels of Gal-1 protein as compared to anulus fibrosus (AF) cells in immature tissues, while exogenous Gal-1 increased both NP and AF cell attachment to laminins and exhibited a similar binding to both cell types in vitro. With aging, Gal-1 levels in NP tissue appeared to decrease. In addition, incubation with B-Gal-1 was able to promote the retention of more than 50% of IVD cells via MACS. Our results provide new findings for the presence and functional role of Gal-1 within IVDs. Similar staining patterns for Gal-1 and LM-511 in IVD tissue suggest that Gal-1 may serve as an adhesion molecule to interact with both cells and laminins. This MACS protocol may be useful for selecting pure IVD cells from mixed cells of pathological tissue.

Changes in the Molecular Phenotype of Nucleus Pulposus Cells with Intervertebral Disc Aging

“…As shown in Table 1, results confirmed higher mRNA expression levels in immature rat NP as compared to AF for several cell surface receptors CD239 (Lu), CD151 (PETA-3), CD24, CD54 (ICAM), CD325 (CDH2) and galectin-1(GAL-1) identified in previous studies of rat, porcine, bovine or human IVDs [27], [30], [33], [37], [38]. mRNA levels for other receptors highly expressed in NP tissues were ALCAM (CD166), TNFRSF12A, PVR (CD155), IGF-1R (CD221), DDR1(CD167), SDC4, RHAMM (CD168) and LAMP1(CD107a).…”

Galectins‐1 and ‐3 in Human Intervertebral Disc Degeneration: Non‐Uniform Distribution Profiles and Activation of Disease Markers Involving NF‐κB by Galectin‐1

“…41 Whereas chondrocytes of the EP were rarely positive for Gal-1, comparable extent of Gal-1 presence was found in cells of the AF and NP. Our data thus extend a previous report on Gal-1 localization in IVDs of lumbar spine of a human adult with no spinal pathology (age: 35 years), 25 by considering degenerated tissues and a comprehensive analysis of all IVD compartments.…”

“…Thus, Gal‐3—alone or in combination with CD24 and carbonic anhydrase 12—has acquired the status of an NP cell marker . Gal‐1 presence was reported in human, porcine and rat IVDs in NP and anulus fibrosus (AF) cells, in which its distribution pattern was similar to that of the matrix glycoprotein laminin (isoform LM‐511), a known counterreceptor of Gal‐1 and ‐3 . Functionally, Gal‐3 presence has been assumed to affect NP cell survival or “the destructive potential” of NP cells .…”

Galectin-1 Couples Glycobiology to Inflammation in Osteoarthritis through the Activation of an NF-κB–Regulated Gene Network

“…In porcine articular chondrocytes, Galectin-1 modulates cellular interactions with constituents of the natural extracellular matrix as well as with an artificial matrix (12,13), and, obviously relevant for degeneration, Galectin-1-dependent signaling upregulates .100-fold matrix metalloproteinase (MMP)-13 gene transcription while at the same time downmodulating type II collagen (COL2A1) gene transcription (13). Reactivity to laminin, a well-known galectin counterreceptor in the extracellular matrix (14,15), was documented for Galectin-1 in the intervertebral disc (16), and a positive Galectin-1 gradient from the proliferative to the hypertrophic zone was reported in growth-plate cartilage (13).…”