Eosinophil Development, Regulation of Eosinophil-Specific Genes, and Role of Eosinophils in the Pathogenesis of Asthma

Abstract

Eosinophils arise from hematopoietic CD34+ stem cells in the bone marrow. They acquire IL-5Rα on their surface at a very early stage during eosinophilopoiesis, and differentiate under the strong influence of interleukin (IL)-5. They then exit to the bloodstream, and enter the lung upon exposure to airway inflammatory signals, including eotaxins. In inflamed tissues, eosinophils act as key mediators of terminal effector functions and innate immunity and in linking to adaptive immune responses. Transcription factors GATA-1, CCAAT/enhancer-binding protein, and PU.1 play instructive roles in eosinophil specification from multipotent stem cells through a network of cooperative and antagonistic interactions. Not surprisingly, the interplay of these transcription factors is instrumental in forming the regulatory circuit of expression of eosinophil-specific genes, encoding eosinophil major basic protein and neurotoxin, CC chemokine receptor 3 eotaxin receptor, and IL-5 receptor alpha. Interestingly, a common feature is that the critical cis-acting elements for these transcription factors are clustered in exon 1 and intron 1 of these genes rather than their promoters. Elucidation of the mechanism of eosinophil development and activation may lead to selective elimination of eosinophils in animals and human subjects. Furthermore, availability of a range of genetically modified mice lacking or overproducing eosinophil-specific genes will facilitate evaluation of the roles of eosinophils in the pathogenesis of asthma. This review summarizes eosinophil biology, focusing on development and regulation of eosinophil-specific genes, with a heavy emphasis on the causative link between eosinophils and pathological development of asthma using genetically modified mice as models of asthma.

Comparative phenotypic profile of subpopulations of peripheral blood leukocytes in European (Bos taurus taurus) and Zebu cattle (Bos taurus indicus)

“…Eosinophils are multifunctional leukocytes that play a role in several disease processes, particularly in allergic diseases and parasitic infections (Gleich and Loegering, 1984;Gleich and Adolphson, 1986;Uhm et al, 2012). Higher numbers of eosinophils in Zebu cattle may be associated with a general increased resistance to parasites compared to European cattle, although a clear cause and effect analysis was beyond the scope of this study.…”

Feasibility Study on Blood Cell Counting Using Mobile Phone-Based Portable Microscope

“…As "Foldscope" use ball lens for convenient use and its magnification capacity is 140x and the resolution of the "Foldscope" is 2 µm. The image and observation acquired in this study, reveals that this magnification is feasible to the histopathological investigation of human blood sample, as human RBC diameter is 6.2- 8.2 µm [6], eosinophil diameter is 12-17 µm [7] and neutrophils average diameter is 8.85 µm [8]. Among several human histopathological procedures [9], blood histological investigations are critical and frequently their essence is very urgent in point of care medical sites, especially in the low resource-setting area [10].…”

The Role of Cytokines in the Pathogenesis of Bronchial Asthma and the Possibilities of Anti-Cytokine Therapy

“…The maturation, mobilization and survival of eosinophils in the airways is determined by IL-3 and GM-CSF, but especially by IL-5, which plays a key role in mediating between eosinophils and other cells in the airways, and the formation of eosinophilic inflammation in patients with BA [15]. IL -5, IL-3 and GM-CSF promote the formation of eosinophils from CD34 hematopoietic progenitor cells, although only IL-5 has a specific effect on eosinophils during development and differentiation [6].…”