“Eat me” imaging and therapy

Abstract

Clearance of apoptotic debris is a vital role of the innate immune system. Drawing upon principles of apoptotic clearance, convenient delivery vehicles including intrinsic anti-inflammatory characteristics and specificity to immune cells can be engineered to aid in drug delivery. In this article, we examine the use of phosphatidylserine (PtdSer), the well-known “eat-me” signal, in nanoparticle-based therapeutics making them highly desirable “meals” for phagocytic immune cells. Use of PtdSer facilitates engulfment of nanoparticles allowing for imaging and therapy in various pathologies and may result in immunomodulation. Furthermore, we discuss the targeting of the macrophages and other cells at sites of inflammation in disease. A thorough understanding of the immunobiology of “eat-me” signals is requisite for the successful application of “eat-me”-bearing materials in biomedical applications.

Liposomes used as a vaccine adjuvant-delivery system: From basics to clinical immunization

“…It should be noted that different PS receptors on different immune cells (not only APCs), upon PS ligation, will manifest different functions, including, particularly, the anti-inflammatory and even tolerogenic effects. These effects, on one hand, are in good accommodation to PS role in inducing rapid phagocytic clearance of dying cells in silence to avoid autoimmunity, but, on the other hand, count obviously against establishing the anti-pathogen immunity [93,94].…”

Ca2+ Flux: Searching for a Role in Efferocytosis of Apoptotic Cells in Atherosclerosis

“…Recently, several studies have shown that synthetic ACs, as examples of non-cell-based therapies, might be used to enhance efferocytosis. An example of such synthetic ACs are the PtdSer-decorated nanoparticles which mimic ACs [171,172]. Hosseini et al showed in apoE-KO mice that PtdSer liposomes, which mimic ACs, effectively reduce atherosclerotic lesions by inducing poly-reactive IgM producing B1a lymphocytes [173].…”

Modulation of the anti‐inflammatory effects of phosphatidylserine‐containing liposomes by PEGylation

“…The incorporation of TRITC-DHPE-labeled PSLs into cells was assessed using fluorescence microscopy. The cell membranes were stained with 250 nM 3,3 0 -dioctadecyloxacarbocyanine perchlorate (DiOC18 [3]) (Invitrogen, Carlsbad, CA) for 20 min prior to PSL treatment. DiOC18(3)-stained cells were incubated with TRITC-DHPE-labeled PSLs for 3 h. Two-channel fluorescence images were obtained using a confocal laser scanning microscope (LSM 700, Carl Zeiss, Germany) at a magnification of 4003.…”