Influence of Apoptotic Bodies and Apoptotic Microvesicles on NO Production in Macrophages.

We studied the effect of extracellular vesicular particles generated during apoptosis by macrophages of M0, M1 and M2 phenotypes on spontaneous and LPS-stimulated production of NO. The fractions of apoptotic bodies and apoptotic microvesicles were obtained in the primary cultures of peritoneal macrophages undergoing apoptosis. The effect of these microparticles on LPS-induced proinflammatory response of recipient macrophages critically depends on the initial phenotype of "donor" macrophages. Microvesicles and especially apoptotic bodies from M1 macrophages stimulate basal NO production. LPS stimulation of these macrophages preincubated with apoptotic bodies was not followed by further growth of NO production; in macrophages preincubated with microvesicles, LPS even suppressed NO production. Apoptotic microparticles obtained from M2 macrophages produced little effect on the basal production of NO. LPS stimulation of macrophages-recipients preincubated with microparticles from M2 macrophages did not enhance NO production. Incubation of macrophages with apoptotic microparticles induces the formation of endotoxic tolerance.

[Influence of cholesterol on macrophage foam cells formation at zymosan-induced inflammation of mice].

It has been shown recently that significant number (to 40% from total population) of macrophage foam cells (MFC) is formed during early time (24 h) of zymosan-induced peritonitis resolution and agonists of peroxisome proliferation activated receptors-α, -γ (PPAR-α, -γ) exert anti-inflammatory action, protecting their formation (Dushkin et al., 2007). The work is devoted to investigate of the influence of cholesterol-containing liposomes (CHL) on dinamic of zimozan-induced peritonitis in C57Bl/6 mice. The accumulation of cholesterol, the change of cytokine production, PPAR-γ activity and cholesterol efflux in macrophages of C57Bl/6 mice has been investigated. The infiltration of neutrophils, amounts of mononuclear cells and MFC formation were significantly increased in peritonel cavity of zymosan-induced mice that led to in expansion of the period of inflammatory resolution and of the period of MFC resolution. If macrophages obtained after zymosan injection mainly accumulated triglycerides (TG) and at high speed incorporated [1-14C]oleate into TG, the injection of CHL after zymosan-indused inflammation lead to dramatic promotion MFC containing primarily free cholesterol and Ch ethers and been aggravation of [1-14C]oleate incorporation into cholesterol ethers in macrophages (mainly for 2 days). It has to shown that CHL against a background of inflammation promoted reduction of fluorescent NBD-cholesterol efflux from macrophages throughout the studied period (5 days) whereas zymosan inhibited cholesterol efflux at the early stages of inflammation (1 and 2 days), then, on 3ed day, the cholesterol efflux was recovered and increased on day 5. At the same time CHL stimulated the production of TNFα and TGFß and inhibited the production of IL-10 and DNA-binding activity of PPAR-γ macrophages obtained at early as well as late stages of zymosan-induced peritonitis (compared with injection zymosan only). Thus, accumulation of cholesterol in inflammatory macrophages and promotion of MFC formation prolog timely resoluti- on of acute inflammation inducing alteration of pro- and anti-inflammatory cytokine balance and evoking the repression of macrophage DNA-binding activity of PPAR-γ and cholesterol efflux.