Related Experiment Videos
Detection of measles virus nucleocapsid transcripts in circulating blood cells from patients with Paget disease
S V Reddy1, F R Singer, L Mallette
1Department of Medicine/Hematology, University of Texas Health Science Center, San Antonio, USA.
Abstract:
Paget disease of bone is characterized by abnormalities in all phases of bone remodeling, but the fundamental cellular abnormality resides in the osteoclast (OCL). Osteoclasts in bone involved by Paget disease contain viral-like nuclear and cytoplasmic inclusions that react with antibodies directed against paramyxovirus nucleocapsid proteins, such as measles virus, respiratory syncytial virus, or canine distemper virus. However, the identity of the virus or the mechanisms responsible for its persistence or pathologic role in Paget disease is unclear. Furthermore, although Paget disease persists for many years, it remains a highly localized process with new lesions rarely if ever developing in previously unaffected bones. Since osteoclasts are formed by fusion of mononuclear precursors derived from colony forming unit-granulocyte macrophage (CFU-GM), the granulocyte-macrophage progenitor, we used reverse transcriptase polymerase chain reaction (RT-PCR) analysis to determine if CFU-GM, more differentiated osteoclast precursors, and peripheral blood cells derived from CFU-GM express measles virus nucleocapsid (MV-N) transcripts. We found that osteoclast precursors, as well as peripheral blood mononuclear cells, express MV transcripts in 9 of 13 patients. Sequence analysis of the PCR amplified products confirmed nucleotide identity of MV-N transcripts expressed in peripheral blood and bone marrow-derived cells from the same patient. In contrast, MV-N transcripts were not detected in OCL precursors or the peripheral blood from 10 normal subjects. In situ hybridization studies using 35S-labeled antisense riboprobes to MV-N transcripts further confirmed the expression of MV transcripts in these cells. Sequence analysis of the PCR amplified product from one of these patients also identified a novel mutation that converted lysine441 to glutamic acid441 in the MV-N transcript. These data demonstrate that OCL precursors and circulating peripheral blood cells also express MV transcripts in patients with Paget disease and suggest that the pagetic marrow microenvironment plays a critical role in maintaining the highly localized nature of the lesions in Paget disease.
Insights
Paget disease of bone involves abnormal osteoclasts potentially linked to measles virus (MV). Researchers found MV transcripts in osteoclast precursors and blood cells of affected patients, suggesting a role in the disease localized to specific bone areas.
Area of Science:
- Bone Biology
- Virology
- Genetics
Background:
- Paget disease of bone is characterized by abnormal bone remodeling, with osteoclasts (OCLs) showing viral-like inclusions.
- These inclusions react with antibodies against paramyxovirus nucleocapsid proteins, but the specific virus and its role remain unclear.
- The disease is highly localized, with new lesions rarely developing in unaffected bones.
Purpose of the Study:
- To investigate the presence of measles virus (MV) nucleocapsid (MV-N) transcripts in osteoclast precursors and peripheral blood cells from Paget disease patients.
- To determine if MV transcripts are expressed in cells involved in osteoclast formation, such as colony forming unit-granulocyte macrophage (CFU-GM).
Main Methods:
- Reverse transcriptase polymerase chain reaction (RT-PCR) was used to detect MV-N transcripts.
- In situ hybridization with labeled antisense riboprobes confirmed transcript presence.
- Sequence analysis was performed on amplified PCR products.
Main Results:
- MV transcripts were detected in osteoclast precursors and peripheral blood mononuclear cells of 9 out of 13 Paget disease patients.
- MV transcripts were not found in precursors or blood cells of normal subjects.
- Sequence analysis confirmed the identity of MV-N transcripts and identified a novel mutation in one patient.
Conclusions:
- Osteoclast precursors and circulating peripheral blood cells express MV transcripts in Paget disease patients.
- These findings suggest a potential role for MV in Paget disease pathogenesis.
- The pagetic marrow microenvironment may be crucial in maintaining the localized nature of the disease.