In vitro and in vivo susceptibility of mouse megakaryocytic progenitors to strain i of parvovirus minute virus of mice.
OBJECTIVE
Intranasal inoculation of the i strain of the parvovirus minute virus of mice (MVMi) into immunodeficient SCID mice induces suppression of myeloid and erythroid progenitors in the bone marrow (BM) and lethal leukopenia. In the present study, we investigated whether the mouse megakaryocytic lineage was susceptible to MVMi.


METHODS
In vitro and in vivo infections with purified MVMi were conducted and their effects on the megakaryocytic lineage studied.


RESULTS
In vitro infection of BM cells showed a multiplicity of infection-dependent inhibition in the colony-forming ability of megakaryocytic progenitors (colony-forming unit megakaryocyte [CFU-MK]). Neutralization or heat inactivation of the virus abrogated this inhibition. Expression of the MVMi nonstructural-1 protein was detected in the in vitro infected and cultured megakaryocytic cells. In vivo, intranasal inoculation of a lethal dose of virus was incapable of producing significant thrombocytopenia, although an increase in mean platelet volume was observed. Significantly, in the BM of these animals, a progressive decrease in CFU-MK was noted from day 14 postinfection, with survival rates less than 1% by day 35 postinfection. At day 35 postinfection, intermediate megakaryocytic differentiation stages showed maintenance of the proportion and ploidy of cells and a moderate decrease in the total number of these cells per femoral BM.


CONCLUSIONS
The results demonstrate that MVMi is capable of inhibiting the proliferative capacity of megakaryocytic committed progenitors both in vitro and in vivo. Moreover, the in vivo data show that depletion of BM CFU-MK is compensated by the system, and platelet counts in the peripheral blood are maintained close to normal values.
Lamana
M L
ML
Department of Molecular and Cellular Biology and Gene Therapy, CIEMAT, Av. Complutense, 22, 28040 Madrid, Spain.
Albella
B
B
Bueren
J A
JA
Segovia
J C
JC
D000281:Administration, Intranasal; D000818:Animals; D001792:Blood Platelets / Q000473:pathology; D001853:Bone Marrow / Q000473:pathology; D002452:Cell Count; D002454:Cell Differentiation; D002461:Cell Line, Transformed; D019070:Cell Lineage; D003114:Colony-Forming Units Assay; D003433:Crosses, Genetic; D005856:Germ-Free Life; D006801:Humans; D016399:Lymphoma, T-Cell / Q000473:pathology; D008533:Megakaryocytes / Q000473:pathology / Q000821:virology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D016513:Mice, SCID; D008915:Minute Virus of Mice / Q000302:isolation & purification / Q000502:physiology*; D023421:Models, Animal; D022423:Myeloid Cells / Q000821:virology; D010322:Parvoviridae Infections / Q000097:blood / Q000662:veterinary* / Q000821:virology; D011123:Polyploidy; D012376:Rodent Diseases / Q000097:blood / Q000821:virology*; D013921:Thrombocytopenia / Q000209:etiology; D014407:Tumor Cells, Cultured; D017361:Viral Nonstructural Proteins / Q000096:biosynthesis
C081367:NS1 protein, minute virus of mice; D017361:Viral Nonstructural Proteins