Human osteoblast‐like cells and osteosarcoma cell lines synthesize macrophage inhibitory protein 1α in response to interleukin 1β and tumour necrosis factor α stimulation in vitro

Abstract

Recent investigations have demonstrated that macrophage inhibitory protein 1alpha (MIP-1alpha) plays a critical role in haematopoiesis. In part, MIP-1alpha limits the differentiation of early haematopoietic cells, thereby ensuring that sufficient quantities of blood precursors are available to meet haematopoietic demands. MIP-1alpha is produced by cells of the marrow microenvironment (marrow stromal cells) in response to a variety of stimuli, including interleukin 1beta (IL-1beta) and tumour necrosis factor alpha (TNF-alpha). Our recent investigations demonstrated that normal human osteoblast-like cells (HOBs) maintain the early phenotype of haematopoietic precursors, like other members of the bone marrow stroma. Although the precise molecular mechanisms for these observations have not been determined, the production of MIP-1alpha remains one such possibility. In the present study, we investigated whether cells of the osteoblast lineage under basal, IL-1beta and/or TNF-alpha stimulation produce MIP-1alpha. We observed that IL-1beta and TNF-alpha stimulated HOBs and human osteosarcoma cells to rapidly express MIP-1alpha mRNA and to secrete large quantities of the protein. MIP-1alpha mRNA and protein was not, however, detected under basal conditions. Perhaps more importantly, enriched human CD34+ bone marrow cells in co-culture may be capable of stimulating the expression of MIP-1alpha mRNA by HOBs in vitro. These findings suggest that human osteoblast-like cells may produce MIP-1alpha in vivo to support haematopoiesis at sites where osteoblasts and haematopoietic cells are closely associated.

Induction of the chemokine stromal-derived factor-1 following DNA damage improves human stem cell function

“…One hundred fifty micrograms per milliliter 5-FU (Sigma Chemical Co., St. Louis, Missouri, USA) was added to the cultures on day 10. On day 14, total cellular RNA was recovered, reverse transcribed, and PCR was performed at 94°C for 1 minute, 60°C for 1 minute, and 72°C for 1 minute for 27 or 35 cycles (semiquantitative and nonquantitative, respectively, followed by a 10-minute extension at 72°C (Cetus DNA thermal cycler; Perkin Elmer Applied Biosystems, Foster City, California, USA) as described previously with sense and antisense primers prepared by the oligonucleotide synthesis core at the University of Michigan (36).…”

Inflammatory Cytokines Stimulate Adrenomedullin Expression Through Nitric Oxide–Dependent and –Independent Pathways

“…ADM thus belongs to the recently discovered group of gene products, such as IL-8 or macrophage inflammatory protein-1␣, that are directly activated both by NO and by cytokines. [32][33][34][35] The pathways along which NO activates ADM gene expression remain to be elucidated. Our findings render an involvement of the classic cGMP signaling pathway rather unlikely, because a classic cGMP analog had no effect on ADM gene expression ( Figure 3, bottom) and because guanylate cyclase inhibition by ODQ could not attenuate the induction of ADM mRNA by NO (Figure 4).…”

The bone marrow niche: habitat to hematopoietic and mesenchymal stem cells, and unwitting host to molecular parasites

“…29 Since this time, our group has demonstrated that osteoblasts support hematopoietic progenitor and long-term culture-initiating cell (LTC-IC) activities in a human system. [30][31][32] Moreover, the proximity of CD34-positive bone marrow cells to osteoblasts can induce the synthesis of several cytokines, including interleukin (IL)-6, 33 leukemia inhibitory factor (LIF), 33 transforming growth factor-b1 (TGF-b1), 31 macrophage inhibitory protein-1a, 34 hepatocyte growth factor (HGF), 32 CXCL12, 35 and IL-7. 35 However, progenitor cells and LTC-IC survival on osteoblasts requires direct cell-to-cell contact, despite the elaboration of soluble cytokines that are necessary, but clearly not sufficient for maintenance of hematopoietic cells on osteoblasts.…”