title: Human Eosinophil Leukocytes Express Protein Disulfide Isomerase in Secretory Granules and Vesicles: Ultrastructural Studies.
abstract: Protein disulfide isomerase (PDI) has fundamental roles in the oxidative folding of proteins in the endoplasmic reticulum (ER) of eukaryotic cells. The study of this molecule has been attracting considerable attention due to its association with other cell functions and human diseases. In leukocytes, such as neutrophils, PDI is involved with cell adhesion, signaling and inflammation. However, the expression of PDI in other leukocytes, such as eosinophils, important cells in inflammatory, allergic and immunomodulatory responses, remains to be defined. Here we used different approaches to investigate PDI expression within human eosinophils. Western blotting and flow cytometry demonstrated high PDI expression in both unstimulated and CCL11/eotaxin-1-stimulated eosinophils, with similar levels in both conditions. By using an immunogold electron microscopy technique that combines better epitope preservation and secondary Fab-fragments of antibodies linked to 1.4-nm gold particles for optimal access to microdomains, we identified different intracellular sites for PDI. In addition to predictable strong PDI labeling at the nuclear envelope, other unanticipated sites, such as secretory granules, lipid bodies and vesicles, including large transport vesicles (eosinophil sombrero vesicles), were also labeled. Thus, we provide the first identification of PDI in human eosinophils, suggesting that this molecule may have additional/specific functions in these leukocytes.
authors.affiliation: Laboratory of Cellular Biology, Department of Biology, Federal University of Juiz de Fora, UFJF, Juiz de Fora, MG, Brazil (FFD,KBA,LASC,RCNM)Department of Pathology (AMD)Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts (RS,PFW,RCNM).
authors.forename: Felipe F
authors.initials: FF
authors.lastname: Dias
authors.affiliation: Laboratory of Cellular Biology, Department of Biology, Federal University of Juiz de Fora, UFJF, Juiz de Fora, MG, Brazil (FFD,KBA,LASC,RCNM)Department of Pathology (AMD)Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts (RS,PFW,RCNM).
authors.forename: Kátia B
authors.initials: KB
authors.lastname: Amaral
authors.affiliation: Laboratory of Cellular Biology, Department of Biology, Federal University of Juiz de Fora, UFJF, Juiz de Fora, MG, Brazil (FFD,KBA,LASC,RCNM)Department of Pathology (AMD)Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts (RS,PFW,RCNM).
authors.forename: Lívia A S
authors.initials: LA
authors.lastname: Carmo
authors.affiliation: Laboratory of Cellular Biology, Department of Biology, Federal University of Juiz de Fora, UFJF, Juiz de Fora, MG, Brazil (FFD,KBA,LASC,RCNM)Department of Pathology (AMD)Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts (RS,PFW,RCNM).
authors.forename: Revital
authors.initials: R
authors.lastname: Shamri
authors.affiliation: Laboratory of Cellular Biology, Department of Biology, Federal University of Juiz de Fora, UFJF, Juiz de Fora, MG, Brazil (FFD,KBA,LASC,RCNM)Department of Pathology (AMD)Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts (RS,PFW,RCNM).
authors.forename: Ann M
authors.initials: AM
authors.lastname: Dvorak
authors.affiliation: Laboratory of Cellular Biology, Department of Biology, Federal University of Juiz de Fora, UFJF, Juiz de Fora, MG, Brazil (FFD,KBA,LASC,RCNM)Department of Pathology (AMD)Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts (RS,PFW,RCNM).
authors.forename: Peter F
authors.initials: PF
authors.lastname: Weller
authors.affiliation: Laboratory of Cellular Biology, Department of Biology, Federal University of Juiz de Fora, UFJF, Juiz de Fora, MG, Brazil (FFD,KBA,LASC,RCNM)Department of Pathology (AMD)Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts (RS,PFW,RCNM) rossana.melo@ufjf.edu.br.
authors.forename: Rossana C N
authors.initials: RC
authors.lastname: Melo
keywords: cell activation; endoplasmic reticulum; human eosinophils; immunonanogold electron microscopy; lipid bodies; protein disulfide isomerase; secretory granules; transmission electron microscopy; vesicular traffic