Network Monitoring of Adhesion/Growth‐Regulatory Galectins: Localization of the Five Canonical Chicken Proteins in Embryonic and Maturing Bone and Cartilage and Their Introduction as Histochemical Tools

Abstract

Divergence from an ancestral gene leads to a family of homologous proteins. Whether they are physiologically distinct, similar, or even redundant is an open question in each case. Defining profiles of tissue localization is a step toward giving diversity a functional meaning. Due to the significance of endogenous sugar receptors (lectins) as effectors for a wide range of cellular activities we have focused on galectins. The comparatively low level of network complexity constituted by only five canonical proteins makes chicken galectins (CGs) an attractive choice to perform comprehensive analysis, here studied on bone/cartilage as organ system. Galectin expression was monitored by Western blotting and immunohistochemistry using non-cross-reactive antibodies. Overall, three galectins (CG-1B, CG-3, CG-8) were present with individual expression patterns, one was found exclusively in the mesenchyme (CG-1A), the fifth (CG-2) not being detectable. The documented extents of separation are a sign for functional divergence; in cases with overlapping stainings, as for example in the osteoprogenitor layer or periosteum, cooperation may also be possible. Recombinant production enabled the introduction of the endogenous lectins as tools for binding-site localization. Their testing revealed developmental regulation and cell-type-specific staining. Of relevance for research on mammalian galectins, this study illustrates that certain cell types can express more than one galectin, letting functional

Galectin-8 induces functional disease markers in human osteoarthritis and cooperates with galectins-1 and -3

“…4 a, were obtained by recombinant production and purified by affinity chromatography of lactose-presenting resin as crucial step, using one- and two-dimensional gel electrophoresis and gel filtration to ascertain purity [ 36 , 59 , 61 ]. Labeling by commercial fluorescent dyes was performed under activity-preserving conditions as described [ 52 ]. The antibody preparation was checked by systematic ELISAs for cross-reactivity against other human galectins, and cross-reactive material was removed chromatographically using protein-loaded beads [ 28 , 30 , 31 ].…”

“…In the case of B cells, Gal-8 positively affects plasma cell formation and antibody production [ 48 ]. Beyond immune cells, the versatility of Gal-8 is underscored by recent findings of (i) osteoclastogenic efficiency through increasing RANKL availability, when adding Gal-8 to co-cultures of murine osteoblasts and bone marrow cells, flanked by in vivo work using overexpressing transgenic and knock-out mice [ 49 , 50 ] and (ii) its involvement in early stages of avian limb morphogenesis where chicken Gal-8 was first detectable in condensing precartilage mesenchyme, later present in the osteoprogenitor layer and eventually in osteoblasts [ 51 , 52 ].…”

Galectin-3 Induces a Pro-degradative/inflammatory Gene Signature in Human Chondrocytes, Teaming Up with Galectin-1 in Osteoarthritis Pathogenesis

“…Fluorescent galectins were prepared under activity-preserving conditions and rigorously checked for maintained activity as described57.…”

Galectin-related protein: An integral member of the network of chicken galectins

“…Evidently, C-GRP was present in this organ at its stage of full maturation. In contrast to the canonical CGs, which are expressed in various adult organs with individual distribution profiles (for overview, please see [7,36]), immunohistochemistry with this antibody preparation detected no evidence for C-GRP positivity in any other tested tissue. Having obtained signals for the mRNAs of the five canonical CGs, the next question to address was the representation of canonical CGs in this tissue and its B cells.…”