B lymphocytes express and lose syndecan at specific stages of differentiation.

Abstract

Lymphopoietic cells require interactions with bone marrow stroma for normal maturation and show changes in adhesion to matrix during their differentiation. Syndecan, a heparan sulfate-rich integral membrane proteoglycan, functions as a matrix receptor by binding cells to interstitial collagens, fibronectin, and thrombospondin. Therefore, we asked whether syndecan was present on the surface of lymphopoietic cells. In bone marrow, we find syndecan only on precursor B cells. Expression changes with pre-B cell maturation in the marrow and with B-lymphocyte differentiation to plasma cells in interstitial matrices. Syndecan on B cell precursors is more heterogeneous and slightly larger than on plasma cells. Syndecan 1) is lost immediately before maturation and release of B lymphocytes into the circulation, 2) is absent on circulating and peripheral B lymphocytes, and 3) is reexpressed upon their differentiation into immobilized plasma cells. Thus, syndecan is expressed only when and where B lymphocytes associate with extracellular matrix. These results indicate that B cells differentiating in vivo alter their matrix receptor expression and suggest a role for syndecan in B cell stage-specific adhesion.

Plasma cell purification from murine bone marrow using a two-step isolation approach

“…Lack of identifying cell surface molecules makes it difficult to isolate a pure population of plasma cells. One unique feature of plasma cells is the expression of relatively high levels of CD138 (Syndecan-1), which has proven to be an effective means of identifying antibody secreting cells in vivo in both humans and mouse (Sanderson et al, 1989;Luque et al, 1998). Using CD138 expression has been less successful for purifying plasma cells directly from bone marrow for use ex vivo because the frequency of plasma cells is rare.…”

Syndecans: multifunctional cell-surface co-receptors

“…During embryonic development syndecan-1 is also expressed by various mesenchymal cells, especially during periods of critical epithelium-mesenchyme interactions [42][43][44][45][46]. Syndecan-1 has been shown to be expressed by pre-B-cells in the bone marrow, but expression is lost immediately before the mature B-cells are released into the circulation [47]. This modulation of syndecan-1 expression has been suggested to be important for regulating interactions of these cells with extracellular matrix.…”

“…In at least one case there is direct evidence demonstrating a role for syndecans in cell-cell adhesion. Some lymphoid cells express syndecan-1 [47]. It has been shown that certain human myeloma cell lines have lost their ability to synthesize syndecan-1.…”

Analysis of MUM1/IRF4 Protein Expression Using Tissue Microarrays and Immunohistochemistry

“…Two such markers, CD138 and VS38, are currently used in paraffin sections. CD138, a member of the syndecan family of integral membrane proteoglycans, is thought to orchestrate cytoadhesive signaling and plays a role in the pathogenesis of multiple myeloma and in the detection of plasmacytic differentiation (17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30). VS38 recognizes a transmembrane protein, p63, which resides in the rough endoplasmic reticulum and mediates increased secretory function (31)(32)(33).…”