A Transgenic FOXJ1-Cre System for Gene Inactivation in Ciliated Epithelial Cells

Ciliated airway epithelial cells are critical for mucosal barrier function, including host defense against pathogens. This cell population is often the primary target and thereby the first line of defense against many common respiratory viruses. It is also the precursor for mucous cells and thereby promotes mucociliary clearance of infectious and other noxious agents. Cells with motile cilia in other organs (e.g., brain and reproductive organs) may also have roles in development and reproduction. However, definitive proof of ciliated cell function is hampered by the lack of strategies to specifically target this cell population for loss of function in vivo. To this end, cell type–specific gene promoters have been combined with the Cre/LoxP system to disrupt genes in airway and alveolar epithelial cell populations expressing surfactant protein C (SP-C) or Clara cell secretory protein (CCSP). By contrast, an analogous system to disrupt gene function in ciliated airway epithelial cells was still needed. Here we report the generation and analysis of mouse lines with a FOXJ1 promoter driving the Cre recombinase and show that this system mediates genomic recombination specifically in ciliated cells. The pattern of recombination recapitulates endogenous FOXJ1 promoter function, being restricted to ciliated cells present in pulmonary airways as well as choroid plexus, ependyma, oviduct, and testis. This transgenic mouse system thereby offers a new strategy for specific knockouts of genes in ciliated cells. It should prove extremely useful for defining ciliated cell function in airway mucosal immunity as well as development and reproduction

Chlorinated lipid species in activated human neutrophils: lipid metabolites of 2-chlorohexadecanal

Neutrophils are important in the host response against invading pathogens. One chemical defense mechanism employed by neutrophils involves the production of myeloperoxidase (MPO)-derived HOCl. 2-Chlorohexadecanal (2-ClHDA) is a naturally occurring lipid product of HOCl targeting the vinyl ether bond of plasmalogens. Previous studies have shown that exogenously-added 2-ClHDA is oxidized to 2-chlorohexadecanoic acid (2-ClHA) and reduced to 2-chlorohexadecanol (2-ClHOH) by endothelial cells. These studies show that both 2-ClHA and 2-ClHOH are produced in activated neutrophils in an MPO- and time-dependent manner and are released by neutrophils into media. 2-ClHDA levels peak following 30 min of phorbol 12-myristate-13-acetate stimulation. In contrast, 2-ClHA and 2-ClHOH levels steadily increased over 60 min, suggesting a precursor-product relationship between 2-ClHDA and both 2-ClHA and 2-ClHOH. Additional experiments using wild-type CHO.K1 and CHO.K1 cells deficient in fatty aldehyde dehydrogenase (FALDH), FAA.K1A, demonstrated that 2-ClHDA oxidation to 2-ClHA is dependent on FALDH activity. Furthermore, mice exposed to intranasal Sendai virus displayed lung neutrophil recruitment, as well as elevated 2-ClHA levels in plasma and bronchoalveolar lavage compared with control-treated mice. Taken together, these data demonstrate, for the first time, that metabolites of 2-ClHDA are produced both in vivo as well as in isolated human neutrophils