No abstract

The rotavirus infection mechanism seems to be a multi-step process which is still not fully understood. The heat shock cognate protein hsc70 has been proposed as being a co-receptor molecule for rotavirus entry into susceptible cells. In this work, an attempt was made to determine the existence of possible domains for VP4 and VP6 binding to hsc70. We selected amino acid sequences 531-554 from VP4 and 280-297 from VP6 on the basis of already recognized sequences for binding to hsc70. This study determined that DLPs and synthetic peptides from VP6 (aa 280-297) and VP4 (aa 531-554), individually or in combination, inhibited rotavirus RRV, YM and WA entry into MA104 and Caco-2 cells in an additive and dose-dependent manner. Hyperimmune sera against these synthetic peptides blocked infection by infectious TLPs. Capture ELISA results showed that DLPs interact with hsc70, probably through VP6 as the specific interaction between hcs70 and DLPs was disrupted by a VP6 peptide. These results suggest that VP6 takes part during rotavirus cell entry by binding to hsc70. This, as well as previous work, provides insight concerning the function of hsc70 within a multi-step model of rotavirus entry.

These results suggest Aa-induced proinflammatory endothelial responses are regulated by rosuvastatin in a mechanism that appears to involve KLF2 activation. Use of rosuvastatin to prevent cardiovascular disease may reduce risk of endothelial activation by bacterial antigens.

Eikenella corrodens is a gram‐negative bacterium, and although primarily associated with periodontal infections or infective endocarditis, it has been identified in coronary atheromatous plaques. The effect of its lipopolysaccharide (LPS) on human coronary artery endothelial cells (HCAECs) is unknown. Our aim was to examine the mechanism underlying the inflammatory response in HCAECs stimulated with E. corrodens‐LPS and to evaluate monocyte adhesion. Endothelial responses were determined by measuring the levels of chemokines and cytokines using flow cytometry. The surface expression of intercellular adhesion molecule 1 (ICAM‐1) was determined using a cell‐based ELISA, and the adhesion of THP‐1 monocytes to HCAECs was also monitored. The involvement of toll‐like receptors (TLRs) 2 and 4 was examined using TLR‐neutralizing antibodies, and activation of extracellular signal‐regulated kinase (ERK)1/2 and nuclear factor‐kappa B (NF‐κB) p65 were measured by western blotting and ELISA, respectively. Eikenella corrodens‐LPS increased secretion of interleukin‐8 (IL‐8), monocyte chemotactic protein 1 (MCP‐1), and granulocyte–macrophage colony‐stimulating factor (GM‐CSF), and expression of ICAM‐1 on the surface of HCAECs, consistent with the increased adhesion of THP‐1 cells. Moreover, E. corrodens‐LPS interacted with TLR4, a key receptor able to maintain the levels of IL‐8, MCP‐1, and GM‐CSF in HCAECs. Phosphorylation of ERK1/2 and activation of NF‐κB p65 were also increased. The results indicate that E. corrodens‐LPS activates HCAECs through TLR4, ERK, and NF‐κB p65, triggering a pro‐atherosclerotic endothelial response and enhancing monocyte adhesion.

Studies have been conducted on the pathogenicity of periodontopathogens in cultures of endothelial cells on two‐dimensional (2D) polystyrene surfaces, where the monolayer formed is not exposed to proteins of the subendothelial matrix. In this work, we developed a culture system by seeding human coronary artery endothelial cells (HCAECs) onto three‐dimensional (3D) scaffolds of collagen type I, a subendothelial protein. The inflammatory responses of the HCAEC monolayers, formed either on 3D scaffolds or directly on a 2D polystyrene plate, to lipopolysaccharide (LPS) from Aggregatibacter actinomycetemcomitans (Aa) and Porphyromonas gingivalis (Pg) were evaluated. The transcription of 3 genes, the secretion of 40 cytokines and 2 prostanoids, and the adhesion of monocytes to 2D and 3D cultures with or without exposure to lipopolysaccharides (control) were assessed. HCAECs exhibited differences in transcriptional and secretory profiles between the 3D and 2D models. In addition, the inflammatory responses of HCAEC to Aa‐LPS and Pg‐LPS differed between the two models. In 3D cultures treated with Aa‐LPS, the levels of IL‐8, RANTES, G‐CSF, ICAM‐1, IL‐6, and TXA2 were significantly higher than those in the controls. In 2D cultures treated with Aa‐LPS, IL‐8, RANTES, G‐CSF, ICAM‐1, TNF‐RI, PGI2, and TXA2 levels were significantly higher than those in their controls. In the presence of Aa‐LPS, monocyte adhesion did not differ between treated and control 3D cultures but was significantly higher in treated 2D cultures than in the controls. In response to Pg‐LPS, cytokine‐prostaglandin secretion and monocyte adhesion did not differ between 3D and 2D cultures. These data indicate that HCAECs respond differently to these two types of LPS.