Angiogenin as a Possible Mediator of Macrophage-Mediated Regulation of Fibroblast Functions.

We studied angiogenin production by human macrophages and evaluated the role of this factor in the macrophage-mediated regulation of fibroblasts. All macrophage subtypes, and especially the efferocytosis-polarized macrophages, M2(LS), actively produced angiogenin. Exogenous recombinant angiogenin dose-dependently enhanced the proliferation and differentiation of dermal fibroblasts. The addition of the angiogenin inhibitor to fibroblasts cultures suppressed the stimulating effect of exogenous angiogenin or M2(LS) conditioned media. These findings indicate the involvement of angiogenin in the macrophage-mediated paracrine regulation of skin fibroblasts.

Influence of Secretome of Different Functional Phenotypes of Macrophages on Proliferation, Differentiation, and Collagen-Producing Activity of Dermal Fibroblasts In Vitro.

We studied the effect of conditioned media of GM-CSF-differentiated human macrophages polarized in M1(LPS), M2a(IL-4), M2c(dexamethasone), and M2(low serum) phenotypes on proliferation, differentiation, and collagen-producing activity of dermal fibroblasts. It was found that M1(LPS) and M2a(IL-4) were characterized by moderate influence on functional activity of fibroblasts. At the same time, soluble factors of M2c(dexamethasone) significantly enhanced the proliferative response of fibroblasts, but not their differentiation and type I collagen production. On the contrary, M2(low serum) generated under conditions of growth factors deficiency had a pronounced stimulating effect on the differentiation of fibroblasts and production of type I collagen by these cells, but moderately stimulated the fibroblast proliferation. Thus, the secretory activity of various functional phenotypes of macrophages is an important mechanism of fibrogenesis regulation.

Effect of M2 Macrophage-Derived Soluble Factors on Proliferation and Apoptosis of SH-SY5Y Cells.

Macrophages play the key role in the regulation of neuroregeneration. For evaluation of the neuroregenerative potential of M2 macrophages, we studied the effect of macrophages polarized with IL-4 (M2a (IL-4)) and by efferocytosis under conditions of serum deprivation (LS, Low Serum; M2(LS)) on proliferative activity and apoptosis of SH-SY5Y cells under conditions of deficiency of growth/serum factors. Conditioned media of both M2(LS) and M2a(IL-4) stimulated proliferation of SH-SY5Y cells. Moreover, soluble factors of M2(LS) and M2a(IL-4) reduced the degree of early apoptosis of SH-SY5Y cells and the protective effect of M2(LS) was observed at earlier terms of culturing. Our findings suggest that M2 macrophages have high neuroregenerative potential that is mediated through soluble factors and manifests itself both in stimulation of proliferation and inhibition of apoptosis of SH-SY5Y cells.

Efferocytosis Modulates Arginase-1 and Tyrosine Kinase Mer Expression in GM-CSF-Differentiated Human Macrophages.

We studied the expression of arginase-1 (Arg1) and tyrosine kinase Mer (MerTK) in GMCSF-differentiated human macrophage populations М0, М1(IFNγ), М2а(IL-4), and М2(low serum) generated under conditions of growth/serum factor deficiency. The maximum relative content of Arg1+ and MerTK+ cells was found in М2 macrophage populations: М2а(IL-4) and М2(low serum). As the uptake of apoptotic cells is the key mechanism of M2 polarization during M2(low serum) generation, we performed a special series of experiments and showed that incubation with allogeneic apoptotic neutrophils significantly increased the percentages of CD206+ macrophages co-expressing Arg1 and MerTK.

Comparison of iron-bearing minerals in ordinary chondrites from H, L and LL groups using Mössbauer spectroscopy with a high velocity resolution.

Ordinary chondrites from H, L and LL groups were studied using Mössbauer spectroscopy with a high velocity resolution. Mössbauer parameters of spectral components were obtained using new fitting model excluding the effect of previous misfits of troilite component. Obtained parameters were related to corresponding iron-bearing minerals in ordinary chondrites. The differences of these minerals content as well as small differences in the hyperfine parameters of the same iron-bearing minerals were revealed for different meteorites. The temperatures of equilibrium cations distribution in silicates were estimated and suitable parameters for classification of H, L and LL chondrites were supposed using Mössbauer parameters.