System-wide molecular dynamics of endothelial dysfunction in Gram-negative sepsis

Abstract

Background Inflammation affecting whole organism vascular networks plays a central role in the progression and establishment of several human diseases, including Gram-negative sepsis. Although the molecular mechanisms that control inflammation of specific vascular beds have been partially defined, knowledge lacks on the impact of these on the molecular dynamics of whole organism vascular beds. In this study, we have generated an in vivo model by coupling administration of lipopolysaccharide with stable isotope labeling in mammals to mimic vascular beds inflammation in Gram-negative sepsis and to evaluate its effects on the proteome molecular dynamics. Proteome molecular dynamics of individual vascular layers (glycocalyx (GC), endothelial cells (EC), and smooth muscle cells (SMC)) were then evaluated by coupling differential systemic decellularization in vivo with unbiased systems biology proteomics. Results Our data confirmed the presence of sepsis-induced disruption of the glycocalyx, and we show for the first time the downregulation of essential molecular maintenance processes in endothelial cells affecting this apical vascular coating. Similarly, a novel catabolic phenotype was identified in the newly synthesized EC proteomes that involved the impairment of protein synthesis, which affected multiple cellular mechanisms, including oxidative stress, the immune system, and exacerbated EC-specific protein turnover. In addition, several endogenous molecular protective mechanisms involving the synthesis of novel antithrombotic and anti-inflammatory proteins were also identified as active in EC. The molecular dynamics of smooth muscle cells in whole organism vascular beds revealed similar patterns of impairment as those identified in EC, although this was observed to a lesser extent. Furthermore, the dynamics of protein posttranslational modifications showed disease-specific phosphorylation sites in the EC proteomes. Conclusions Together, the novel findings reported here provide a broader picture of the molecular dynamics that take place in whole organism vascular beds in Gram-negative sepsis inflammation. Similarly, the obtained data can pave the way for future therapeutic strategies aimed at intervening in specific protein synthesis mechanisms of the vascular unit during acute inflammatory processes.

Omics of endothelial cell dysfunction in sepsis

“…None of these studies report KEGG pathways and/or GO hits that are downregulated. Consistent with genomic studies, proteins expressed correlate with the upregulation of KEGG pathways and GO hits related to coagulation, cell adhesion and immune response (56,57,58,59,60,61,62). Thus, proteins correspond with gene expression to determine final cellular pathways and biological processes overexpressed in septic-like conditions.…”

“…Other than causing differential regulation of coagulation, cell adhesion and immune response proteins in ECs, sepsis has been shown to affect the glycocalyx (a gel-like layer composed of proteoglycans coating ECs) and vascular smooth muscle cells (VSMCs) (7,58). The synthesis of new peptides in response to sepsis related to lipid transport (e.g.…”

“…The synthesis of new peptides in response to sepsis related to lipid transport (e.g. Apo family), immunity or oxidative stress (C7) is all downregulated in the glycocalyx (58). Thus, designing studies investigating potential proteins that shed from the glycocalyx during sepsis would be beneficial.…”

ER stress induced immunopathology involving complement in CADASIL: implications for therapeutics

“…For protein identification precursor mass tolerance was set at 10 ppm and a reporter ion integrated tolerance at 20 ppm. Label-free quantification of proteins was based on spectral count as previously reported [ 16 ]. The most abundant proteins identified (spectral count > 20) were included in the performed analyses as indicated in Supplementary Table 1.…”

Oral Microbiota, Its Equilibrium and Implications in the Pathophysiology of Human Diseases: A Systematic Review

“…It has also been demonstrated that administration in mice of P. gingivalis , one of the main pathogenic bacteria present in periodontitis, increases intestinal permeability and, as a consequence, facilitates the transfer of LPS through the intestinal barrier [ 48 , 128 ]. This leakage of LPS leads to upregulated serum LPS levels, which in turn have been demonstrated to trigger systemic inflammation [ 48 , 128 , 129 ]. Repeated oral application of P. gingivalis induces neurodegeneration and the formation of extracellular Aβ42 in young adult wild type mice, strongly suggesting that low grade chronic periodontal infection with this pathogen can result in the development of neuropathology consistent with that of AD [ 130 ].…”