Involvement of Osteocytes in the Action of Pasteurella multocida Toxin.

Abstract

Pasteurella multocida toxin (PMT) causes progressive atrophic rhinitis with severe turbinate bone degradation in pigs. It has been reported that the toxin deamidates and activates heterotrimeric G proteins, resulting in increased differentiation of osteoclasts and blockade of osteoblast differentiation. So far, the action of PMT on osteocytes, which is the most abundant cell type in bone tissue, is not known. In MLO-Y4 osteocytes, PMT deamidated heterotrimeric G proteins, resulting in loss of osteocyte dendritic processes, stress fiber formation, cell spreading and activation of RhoC but not of RhoA. Moreover, the toxin caused processing of membrane-bound receptor activator of NF-κB ligand (RANKL) to release soluble RANKL and enhanced the secretion of osteoclastogenic TNF-α. In a co-culture model of osteocytes and bone marrow cells, PMT-induced osteoclastogenesis was largely increased as compared to the mono-culture model. The enhancement of osteoclastogenesis observed in the co-culture was blocked by sequestering RANKL with osteoprotegerin and by an antibody against TNF-α indicating involvement of release of the osteoclastogenic factors from osteocytes. Data support the crucial role of osteocytes in bone metabolism and osteoclastogenesis and identify osteocytes as important target cells of PMT in progressive atrophic rhinitis.

• Authors: Hannah Heni, Julia K Ebner, Gudula Schmidt, Klaus Aktories, Joachim H C Orth
• Journal: Toxins (Toxins (Basel)) Vol. 10 Issue 8 (08 13 2018) ISSN: 2072-6651 [Electronic] Switzerland
• PMID: 30104531 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Bacterial Proteins
• Bacterial Toxins
• Pasteurella multocida toxin
• RANK Ligand
• Tnfsf11 protein, mouse
• Tumor Necrosis Factor-alpha
• GTP-Binding Proteins

Topics

• Animals
• Bacterial Proteins (toxicity)
• Bacterial Toxins (toxicity)
• Cell Line
• Coculture Techniques
• Female
• GTP-Binding Proteins (metabolism)
• Macrophages (drug effects, physiology)
• Mice, Inbred C57BL
• Osteocytes (drug effects, physiology)
• Osteogenesis (drug effects)
• RANK Ligand (metabolism)
• Tumor Necrosis Factor-alpha (metabolism)