Strating the activities of the host and sustaining homeostasis. The plasticity of hematopoietic progenitor cells in the BM bestows upon them the ultimate power to restore homeostasis. Infectious agents are a type of stimulation that likely disturb the equilibrium, requiring BM progenitors to respond to re-establish order. Dengue is one of the most important vector-borne diseases in humans. Although the disease predominantly circulates in tropical and subtropical zones, it has recently been acknowledged as a potential public health threat in several other locations around the world. The majority of those infections remain asymptomatic, but many experience dengue fever (DF) that is a self-limited illness. Only a small percentage of affected subjects progress to the very severe and DprE1-IN-2 life-threatening clinical form termed dengue hemorrhagic fever (DHF) accompanied with shock syndrome (DSS), which is characterized by increased vascular permeability, plasma leakage and internal bleeding. The degree of thrombocytopenia has been demonstrated to significantly correlate with the severity of the disease. Understanding the mechanisms accounting for the drop in platelet counts has been one of the central themes for several decades. The following processes, acting successively or in combination, have been demonstrated to interfere with the number of platelets in the peripheral blood of dengue patients: reduced platelet production through early transient marrow suppression with damage to megakaryocytes [9,15]; platelet aggregation with endothelial cells upon dengue virus activation [16,17]; hemo-phagocytosis [18,19]; and finally, immune destruction of platelets displaying dengue-antibody complexes on their membranes [20]. Profound hematopoietic suppression has been noted to occur in dengue virus infected patients early 16574785 abstract’ target=’resource_window’>18325633 post infection occurring prior to hospital admission [5?]. Thus, direct suppressive action of the virus on megakaryocytes was suggested as a mechanism contributing to thrombocytopenia long ago [21], however this hypothesis was never properly evaluated and remained un-confirmed. We first observed that unfractionated BM cultures are highly permissive for dengue virus infection relative to purified populations of BM mononuclear cells. A requirement for the presence of other cell lineages for optimum growth and survival of megakaryocytes and/or that the Ficoll-Paque gradient separation procedure may serve to shear critical cell surface molecules required for optimal infection and thus account for the difference. Results obtained using a combination of immunohistochemical staining and electron microscopy JSI124 web imaging techniques authenticate that multi-lobulated megakaryocytes are highly permissive for dengue virus infection in vitro. This can be inferred from previous findings indicating that hematopoietic cells other than megakaryocytes are very seldom polyploid in healthy BM [22?4]. Productive infection of these megakaryocytic cells likely plays an important part in the development of thrombocytopenia characteristic of dengue infected patients. Megakaryocytes are one of the most unique cells in the mammalian system, accounting for only 1 of healthy BM. They express all proteins required for cell division and yet never divide to generate daughter cells. The surface area of the cell membrane progressively expands to an enormous size, which then, via internal operational signaling, extends itself into a demarcation membrane that sheds to produce pl.Strating the activities of the host and sustaining homeostasis. The plasticity of hematopoietic progenitor cells in the BM bestows upon them the ultimate power to restore homeostasis. Infectious agents are a type of stimulation that likely disturb the equilibrium, requiring BM progenitors to respond to re-establish order. Dengue is one of the most important vector-borne diseases in humans. Although the disease predominantly circulates in tropical and subtropical zones, it has recently been acknowledged as a potential public health threat in several other locations around the world. The majority of those infections remain asymptomatic, but many experience dengue fever (DF) that is a self-limited illness. Only a small percentage of affected subjects progress to the very severe and life-threatening clinical form termed dengue hemorrhagic fever (DHF) accompanied with shock syndrome (DSS), which is characterized by increased vascular permeability, plasma leakage and internal bleeding. The degree of thrombocytopenia has been demonstrated to significantly correlate with the severity of the disease. Understanding the mechanisms accounting for the drop in platelet counts has been one of the central themes for several decades. The following processes, acting successively or in combination, have been demonstrated to interfere with the number of platelets in the peripheral blood of dengue patients: reduced platelet production through early transient marrow suppression with damage to megakaryocytes [9,15]; platelet aggregation with endothelial cells upon dengue virus activation [16,17]; hemo-phagocytosis [18,19]; and finally, immune destruction of platelets displaying dengue-antibody complexes on their membranes [20]. Profound hematopoietic suppression has been noted to occur in dengue virus infected patients early 16574785 abstract’ target=’resource_window’>18325633 post infection occurring prior to hospital admission [5?]. Thus, direct suppressive action of the virus on megakaryocytes was suggested as a mechanism contributing to thrombocytopenia long ago [21], however this hypothesis was never properly evaluated and remained un-confirmed. We first observed that unfractionated BM cultures are highly permissive for dengue virus infection relative to purified populations of BM mononuclear cells. A requirement for the presence of other cell lineages for optimum growth and survival of megakaryocytes and/or that the Ficoll-Paque gradient separation procedure may serve to shear critical cell surface molecules required for optimal infection and thus account for the difference. Results obtained using a combination of immunohistochemical staining and electron microscopy imaging techniques authenticate that multi-lobulated megakaryocytes are highly permissive for dengue virus infection in vitro. This can be inferred from previous findings indicating that hematopoietic cells other than megakaryocytes are very seldom polyploid in healthy BM [22?4]. Productive infection of these megakaryocytic cells likely plays an important part in the development of thrombocytopenia characteristic of dengue infected patients. Megakaryocytes are one of the most unique cells in the mammalian system, accounting for only 1 of healthy BM. They express all proteins required for cell division and yet never divide to generate daughter cells. The surface area of the cell membrane progressively expands to an enormous size, which then, via internal operational signaling, extends itself into a demarcation membrane that sheds to produce pl.
