Novel approach to anti-microbial host defense with molecular shields with EPA and DHA analogs

#During both acute and chronic inflammatory processes, epithelial cells coordinate mucosal responses to infection. For this reason, much recent attention has been paid to understanding innate, anti-inflammatory pathways utilized by mucosal epithelial cells. Of particular interest are small molecules that exhibit anti-inflammatory activity.

#The initial encounter of microbes with human tissues and cells occurs at the level of mucosal tissues. Epithelial cells line all mucosal organs, and thus, the epithelium is the key interface for microbial interactions. Importantly, microorganisms which interact with mucosal surfaces may be beneficial (e.g. normal flora) or pathogenic (e.g. infectious agents), and as a result, epithelial cells have adapted mechanisms to selectively kill or inactivate invading microorganisms. As part of this arsenal, epithelial cells express antimicrobial peptides whose primary function includes killing of invading microorganisms. This family of unrelated peptides includes peroxidase, lactoferrin, lysozyme, phospholipase A2, secretory leukoprotease inhibitor (SLPI), and defensins (1). Among the innate anti-inflammatory and/or anti-infective defense molecules of humans is the bactericidal/permeability-increasing protein (BPI), a 55-60 kDa protein found in neutrophil azuorphilc granules, on the neutrophil cell surface, and to a lesser extent, in specific granules of eosinophils(2-4). BPI selectively exerts multiple anti-infective actions against gram-negative bacteria, including cytotoxicity through damage to bacterial inner/outer membranes, neutralization of bacterial lipopolysaccharide (endotoxin), as well as serving as an opsonin for phagocytosis of gram-negative bacteria by neutrophils (3, 5). Structural characterization of BPI reveals a symmetrical bipartite molecule containing a cationic N-terminal region for antibacterial and endotoxin neutralization and a C-terminal motif necessary for bacterial opsonization (6).

#Therefore, a need exists for the stimulation, production, and/or release of BPI from body tissues to help combat, for example, bacterial invasion and/or infection.

#The invention will be more fully understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

#FIG. 1 depicts localization of BPI to the cell surface. BPI was localized by confocal microscopy in non-permeabilized OKF6 or Caco2 cells, as indicated. Shown in FIG. 2 are confocal sections through the mid-zone, sub-junctional portion of epithelial monolayers. Also shown is a control section omitting the primary Ab. Representative experiment from n=2.

#FIG. 2 depicts the role of epithelial BPI in bacterial killing. In panel A, adherent Caco2 cells were incubated with S. typhimurium at a ratio of 50 bacteria per epithelial cell and examined for killing over a 90 min period. Shown in FIG. 2 are pooled results from three experiments. In panel B, the role of BPI in Caco2 killing of S. typhimurium over a 60 min period was assessed by incubation of cells (Cell Assoc.) or supernatants with anti-BPI or NGS. The bacterial control omitting epithelial cells is also shown. Double asterix (**) indicates significantly different from anti-BPI, p<0.01).

#The features and other details of the invention will now be more particularly described and pointed out in the claims. It will be understood that the particular embodiments of the invention are shown by way of illustration and not as limitations of the invention. The principle features of this invention can be employed in various embodiments without departing from the scope of the invention.

#Abbreviations used throughout the present application include the following and are included here for convenience. ATLM, aspirin-triggered lipid mediators; COX, cyclooxygenase I, II (isoforms); EC, endothelial cells; LC/MS/MS, liquid chromatography tandem mass spectrometry; LO, lipoxygenase; LT, leukotriene; PG, prostaglandins; PMN, polymorphonuclear leukocyte; EPA eicosapentaenoic acid; HEPE, hydroxyeicosapentaenoic acid; C20:5 (eicosapentanoic acid, EPA, an ω-3 fatty acid); and C22:6 (docosahexaenoic acid, DHA, ω-3 fatty acid).

#It has been surprisingly discovered that eicosapentaenoic acid (EPA) analogs and docosahexaenoic acid (DHA) analogs of the invention, discussed infra, can be utilized for the stimulation, release and increased secretion of bactericidal permeability increasing protein (BPI) from various tissues, i.e., mucosal cells, epithelial cells, for combating infection and/or the invasion of bacteria in a subject. Consequently, the compounds disclosed herein are useful for the treatment and prevention of infection in a subject.