A mechanism of self-lipid endocytosis mediated by the receptor Mincle.

Cellular lipid uptake (through endocytosis) is a basic physiological process. Dysregulation of this process underlies the pathogenesis of diseases such as atherosclerosis, obesity, diabetes, and cancer. However, to date, only some mechanisms of lipid endocytosis have been discovered. Here, we show a previously unknown mechanism of lipid cargo uptake into cells mediated by the receptor Mincle. We found that the receptor Mincle, previously shown to be a pattern recognition receptor of the innate immune system, tightly binds a range of self-lipids. Moreover, we revealed the minimal molecular motif in lipids that is sufficient for Mincle recognition. Superresolution microscopy showed that Mincle forms vesicles in cytoplasm and colocalizes with added fluorescent lipids in endothelial cells but does not colocalize with either clathrin or caveolin-1, and the added lipids were predominantly incorporated in vesicles that expressed Mincle. Using a model of ganglioside GM3 uptake in brain vessel endothelial cells, we show that the knockout of Mincle led to a dramatic decrease in lipid endocytosis. Taken together, our results have revealed a fundamental lipid endocytosis pathway, which we call Mincle-mediated endocytosis (MiME), and indicate a prospective target for the treatment of disorders of lipid metabolism, which are rapidly increasing in prevalence.

Forces of interaction of red blood cells and endothelial cells at different concentrations of fibrinogen: Measurements with laser tweezers in vitro.

Blood microrheology depends on the constituents of blood plasma, the interaction between blood cells resulting in red blood cell (RBC) and platelets aggregation, and adhesion of RBC, platelets and leukocytes to vascular endothelium. The main plasma protein molecule -actuator of RBC aggregation is fibrinogen. In this paper the effect of interaction between the endothelium and RBC at different fibrinogen concentrations on the RBC microrheological properties was investigated in vitro. Laser tweezers were used to measure the RBC-endothelium interaction forces. It was shown for the first time that the interaction forces between RBC and endothelium are comparable with the RBC aggregation forces, they increase with fibrinogen concentration and reach the saturation level of about 4 pN at the concentration of 4 mg/ml. These results are important for better understanding the mechanisms of RBC and endothelium interaction and developing the novel therapeutic protocols of the microrheology correction in different pathologies.

Novel Cationic Meso-Arylporphyrins and Their Antiviral Activity against HSV-1.

This work is devoted to the search for new antiherpes simplex virus type 1 (HSV-1) drugs among synthetic tetrapyrroles and to an investigation of their antiviral properties under nonphotodynamic conditions. In this study, novel amphiphilic 5,10,15,20-tetrakis(4-(3-pyridyl-n-propanoyl)oxyphenyl)porphyrin tetrabromide (3a), 5,10,15,20-tetrakis(4-(6-pyridyl-n-hexanoyl)oxyphenyl)porphyrin tetrabromide (3b) and known 5,10,15,20-tetrakis(1-methyl-4-pyridinio)porphyrin tetraiodide (TMePyP) were synthesized, and their dark antiviral activity in vitro against HSV-1 was studied. The influence of porphyrin's nanosized delivery vehicles based on Pluronic F127 on anti-HSV-1 activity was estimated. All the received compounds 3a, 3b and TMePyP showed virucidal efficiency and had an effect on viral replication stages. The new compound 3b showed the highest antiviral activity, close to 100%, with the lowest concentration, while the maximum TMePyP activity was observed with a high concentration; porphyrin 3a was the least active. The inclusion of the synthesized compounds in Pluronic F-127 polymeric micelles had a noticeable effect on antiviral activity only at higher porphyrin concentrations. Action of the received compounds differs by influence on the early or later reproduction stages. While 3a and TMePyP acted on all stages of the viral replication cycle, porphyrin 3b inhibited viral replication during the early stages of infection. The resulting compounds are promising for the development of utilitarian antiviral agents and, possibly, medical antiviral drugs.

Topical treatment with the bacterium-derived c-Met agonist InlB321/15 accelerates healing in the abrasion wound mouse model.

Studies of factors affecting wound-healing rates are encouraged by a critical need for new treatments to manage an increasing burden of non-healing wounds. The InlB protein produced by the Gram-positive bacterium Listeria monocytogenes is an agonist of the tyrosine kinase receptor c-Met and a functional analog of the hepatocyte growth factor (HGF), which is a mammalian ligand of c-Met. The recombinant InlB321 protein, which is the c-Met-binding InlB domain (amino acids 31-321), was cloned from the L. monocytogenes serovar 4b clinical strain VIMHA015 and serovar 1/2a strain EGDe (InlB321/15 and InlB321/EGDe, respectively). Both InlB321 variants stimulated proliferation of endothelial HUVEC cells. InlB321/15 was more active in Erk1/2 phosphorylation assay, and more potent than InlB321/EGDe in the 2D-scratch wound-healing assay. Scratch closure reached 86%, 29% and 72% for InlB321/15, InlB321/EGDe and HGF, respectively, 72 h post-wounding (p < 0.05). Topically applied glycerol-mixed InlB321/15 (300 µg ml- 1) increased abrasion wound-healing rates in mice. The 50% wound closing time (CT50) was reduced by InlB321/15 (4.18 ± 0.91 days; CI: 3.05; 5.31) compared with control animals (5.51 ± 1.21 days; CI: 4.01; 7.01; p < 0.05). Taken together, obtained results suggested a potential of InlB321/15 as a means of accelerating wound healing.

The Effect of Smooth Muscle Cells and Leukocytes on HSV-1 Reproduction in Cultured Human Endothelial Cells.

The ability of intima smooth muscle cells (SMCs) and blood leukocytes to control the development of Herpes simplex type 1 virus (HSV-1) infection in human vascular endothelial cells (ECs) was studied under a co-culture conditions. It was shown that cultured ECs supported HSV-1 reproduction followed by cytopathogenic effect (CPE) and accumulation of infectious virus in the cell culture medium. At the multiplicity of infection (MOI) ranging from 1 to 0.1 TCID(50), co-culture of ECs with SMCs growing in TransWell inserts significantly delayed the development of signs of virus reproduction. Similar effect was found, when after infection ECs were cultured in SMC-conditioned medium. At a MOI 0.001, SMC-conditioned media completely abrogated both CPE and virus accumulation, and leaded to the establishment of latent infection: this infection could persist in a subculture of infected cells and be reactivated after substitution of conditioned medium by standard EC growing medium. The decrease of virus infection in ECs was also observed, when the cells were cultured in medium conditioned by human peripheral blood leukocytes, containing numerous cytokines (but not IFN). At a MOI 0.001 we have found neither visual signs of infection, nor virus reproduction; the PCR analyses were also negative. The results obtained suggest that resident cellular components of the vascular intima (SMCs) and leukocytes may be involved in the mechanism of endothelium-virus interaction and modify the pathogenesis of HSV-1 disease.

Herpes simplex type I virus infected human vascular endothelial cells induce the production of anti-viral and proinflammatory factors by peripheral blood leukocytes in vitro.

Viral infection of the vascular wall cellular elements is involved in development of several pathophysiological events, including vasculitis, transplant rejection, and atherosclerosis. Previously, we have shown that cultured human vascular endothelial cells (ECs) may be effectively infected with herpes simplex type I virus (HSV-1), and this cultural model could be a useful tool for the explanation of many aspects of viral disease. In this study, we investigated the effects of conditioned media (CM) of peripheral blood mononuclear cells (PBMCs) on HSV-1 reproduction and cell adhesion molecule expression in cultured ECs. PBMC-CM induced the delay of virus reproduction or inhibition of virus reproduction. Effects of CM correlated with multiplicity of infection used for EC, time of PBMC contact with infected and glutaraldehyde-fixed endothelium, and the level of IFNs and cytokine production. Passages of and CM-treated and infected cells without signs of virus reproduction were, sometimes, followed by virus reactivation. However, at a low level of infection of CM-treated ECs the virus reactivation was not observed even after 2-3 cell passages. Neutralizing antibodies against IFN-alpha, IFN-gamma, and TNF-alpha, used separately or together, significantly abrogated the delaying and/or inhibiting action of CM. Additionally, PBMC-CM significantly increased the expression of ICAM-1 and VCAM-1 on cultured ECs. The strongest cell activation was induced by CM obtained from PBMCs co-incubated with virus-infected endothelium. Obtained results suggest that primed leukocytes produce soluble factors with either anti-viral or pro-inflammatory activity, and the effect of PBMC-CM may have a bi-directional action. On the one hand, due to production of interferons and several cytokines CM sets up HSV-1 latency or virus elimination from cultured cells. On the other, the same cytokines act on infected and/or neighboring ECs and initiate the cascade of inflammatory reactions in the vascular wall.

Herpes Simplex Type I Virus Infection of Cultured Human Vascular Endothelial Cells: Expression of Cell Adhesion Molecules and Induction of Interferon and Cytokine Production by Blood Mononuclear Cells.

The expression of cell adhesion molecules, P- and E-selectins, ICAM-1, and VCAM-1, was studied in cultured human vascular endothelial cells (ECs) infected by herpes simplex type I virus (HSV-1). It was shown that ECs without any signs of the cytopathogenic effect (CPE) expressed on their surface P- and E-selectins as soon as 24 h after infection. No appearance of VCAM-1 or increase in ICAM-1 expression was detected. Peripheral blood mononuclear cells (PBMCs) isolated by gradient centrifugation adhered preferentially with HSV-1-infected morphologically unchanged ECs but not with cells modified in result of CPE. The interferon and cytokine production by PBMCs was assayed after their contact with infected and glutaraldehyde-fixed ECs. The secretion of IFN-alpha, IFN-gamma, IL-1, IL-6, and TNF-alpha (but not of IL-4) was found to be inducible and correlated with the multiplicity of infection. Obtained results allow to consider a described cell culture system as a model for further investigation of initial stages of HSV-1 infection and of pathogenesis of vascular disease.

TNF-alpha and gamma-irradiation induced activation of the Salmonella typhimurium reproduction in the organs of infected animals.

The goal of the current work is to determine the role of the TNF-alpha on the activation of the bacterial growth in an in vivo system. In order to reach this goal we studied the dynamics of the reproduction of vegetative forms of Salmonella and the recultivation of non-cultivating forms of Salmonella in infected animals. Experiments have been conducted both on animals that had been injected with exogenous TNF together with bacterial suspension and on animals that had been exposed to gamma-radiation before infection, since it is known that irradiation increases the secretion of TNF. We demonstrate that in all cases the increase in the level of TNF-alpha in animals leads to the activation of the Salmonella growth. Moreover, in this paper we present the data obtained by the method of molecular display on the identification of genes that are highly expressed in the Salmonella cells cultivated in vitro in the presence of TNF.