scholarly journals Platelets Are Critical Key Players in Sepsis

2019 ◽  
Vol 20 (14) ◽  
pp. 3494 ◽  
Author(s):  
Fanny Vardon-Bounes ◽  
Stéphanie Ruiz ◽  
Marie-Pierre Gratacap ◽  
Cédric Garcia ◽  
Bernard Payrastre ◽  
...  

Host defense against infection is based on two crucial mechanisms: the inflammatory response and the activation of coagulation. Platelets are involved in both hemostasis and immune response. These mechanisms work together in a complex and synchronous manner making the contribution of platelets of major importance in sepsis. This is a summary of the pathophysiology of sepsis-induced thrombocytopenia, microvascular consequences, platelet-endothelial cells and platelet–pathogens interactions. The critical role of platelets during sepsis and the therapeutic implications are also reviewed.

2019 ◽  
Vol 18 (1) ◽  
pp. 78-87 ◽  
Author(s):  
Jian-kai Yang ◽  
Hong-jiang Liu ◽  
Yuanyu Wang ◽  
Chen Li ◽  
Ji-peng Yang ◽  
...  

Background and Objective: Exosomes communicate inter-cellularly and miRNAs play critical roles in this scenario. MiR-214-5p was implicated in multiple tumors with diverse functions uncovered. However, whether miR-214-5p is mechanistically involved in glioblastoma, especially via exosomal pathway, is still elusive. Here we sought to comprehensively address the critical role of exosomal miR-214-5p in glioblastoma (GBM) microenvironment.Methods:The relative expression of miR-214-5p was determined by real-time PCR. Cell viability and migration were measured by MTT and transwell chamber assays, respectively. The secretory cytokines were measured with ELISA kits. The regulatory effect of miR-214-5p on CXCR5 expression was interrogated by luciferase reporter assay. Protein level was analyzed by Western blot.Results:We demonstrated that miR-214-5p was aberrantly overexpressed in GBM and associated with poorer clinical prognosis. High level of miR-214-5p significantly contributed to cell proliferation and migration. GBM-derived exosomal miR-214-5p promoted inflammatory response in primary microglia upon lipopolysaccharide challenge. We further identified CXCR5 as the direct target of miR-214- 5p in this setting.Conclusion:Overexpression of miR-214-5p in GBM modulated the inflammatory response in microglia via exosomal transfer.


Cancers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2999
Author(s):  
Deborah Reynaud ◽  
Roland Abi Nahed ◽  
Nicolas Lemaitre ◽  
Pierre-Adrien Bolze ◽  
Wael Traboulsi ◽  
...  

The inflammatory gene NLRP7 is the major gene responsible for recurrent complete hydatidiform moles (CHM), an abnormal pregnancy that can develop into gestational choriocarcinoma (CC). However, the role of NLRP7 in the development and immune tolerance of CC has not been investigated. Three approaches were employed to define the role of NLRP7 in CC development: (i) a clinical study that analyzed human placenta and sera collected from women with normal pregnancies, CHM or CC; (ii) an in vitro study that investigated the impact of NLRP7 knockdown on tumor growth and organization; and (iii) an in vivo study that used two CC mouse models, including an orthotopic model. NLRP7 and circulating inflammatory cytokines were upregulated in tumor cells and in CHM and CC. In tumor cells, NLRP7 functions in an inflammasome-independent manner and promoted their proliferation and 3D organization. Gravid mice placentas injected with CC cells invalidated for NLRP7, exhibited higher maternal immune response, developed smaller tumors, and displayed less metastases. Our data characterized the critical role of NLRP7 in CC and provided evidence of its contribution to the development of an immunosuppressive maternal microenvironment that not only downregulates the maternal immune response but also fosters the growth and progression of CC.


2018 ◽  
Vol 315 (5) ◽  
pp. H1477-H1485 ◽  
Author(s):  
Kimiko Yamamoto ◽  
Hiromi Imamura ◽  
Joji Ando

Vascular endothelial cells (ECs) sense and transduce hemodynamic shear stress into intracellular biochemical signals, and Ca2+ signaling plays a critical role in this mechanotransduction, i.e., ECs release ATP in the caveolae in response to shear stress and, in turn, the released ATP activates P2 purinoceptors, which results in an influx into the cells of extracellular Ca2+. However, the mechanism by which the shear stress evokes ATP release remains unclear. Here, we demonstrated that cellular mitochondria play a critical role in this process. Cultured human pulmonary artery ECs were exposed to controlled levels of shear stress in a flow-loading device, and changes in the mitochondrial ATP levels were examined by real-time imaging using a fluorescence resonance energy transfer-based ATP biosensor. Immediately upon exposure of the cells to flow, mitochondrial ATP levels increased, which was both reversible and dependent on the intensity of shear stress. Inhibitors of the mitochondrial electron transport chain and ATP synthase as well as knockdown of caveolin-1, a major structural protein of the caveolae, abolished the shear stress-induced mitochondrial ATP generation, resulting in the loss of ATP release and influx of Ca2+ into the cells. These results suggest the novel role of mitochondria in transducing shear stress into ATP generation: ATP generation leads to ATP release in the caveolae, triggering purinergic Ca2+ signaling. Thus, exposure of ECs to shear stress seems to activate mitochondrial ATP generation through caveola- or caveolin-1-mediated mechanisms. NEW & NOTEWORTHY The mechanism of how vascular endothelial cells sense shear stress generated by blood flow and transduce it into functional responses remains unclear. Real-time imaging of mitochondrial ATP demonstrated the novel role of endothelial mitochondria as mechanosignaling organelles that are able to transduce shear stress into ATP generation, triggering ATP release and purinoceptor-mediated Ca2+ signaling within the cells.


2020 ◽  
Vol 1 (9) ◽  
pp. 64-71
Author(s):  
E. A. Klimov ◽  
◽  
E. K. Novitskaya ◽  
S. N. Koval’chuk ◽  
◽  
...  

Intercellular adhesion molecule CD209 (DC-SIGN) is a membrane C-type lectin receptor expressed on the surface of dendritic cells and macrophages. CD209 plays an important role in innate immunity. Many studies have shown the possibility of interaction of the CD209 molecule with a number of dangerous pathogens of humans and animals. This review summarizes information on the structure of the CD209 gene and its product, describes the role of the CD209 protein in the immune response, in the migration of dendritic cells from the blood to the tissue, and their interaction with neutrophils. The currently known signaling pathway of activation through the CD209 inflammatory response is presented. The role of CD209 as an endocytic antigen receptor and the participation of the protein in immune evasion of pathogens are discussed. The mechanisms known to date for the development of infections caused by pathogens of various nature in animals are described.


2020 ◽  
Vol 26 (1) ◽  
Author(s):  
Zhimin Zhang ◽  
Mingzhu Lv ◽  
Xiang Wang ◽  
Zheng Zhao ◽  
Daolong Jiang ◽  
...  

Abstract Background The oncogenic role of the newly identified lncRNA LUADT1 has been revealed in lung adenocarcinoma. It was reported that LUADT1 plays a critical role in multiple human diseases. This study was carried out to investigate the role of LUADT1 in sepsis. Methods Sixty patients with sepsis and sixty healthy volunteers were recruited for this study. Plasma samples were collected from all participants. Human primary coronary artery endothelial cells were also used in this study. The expression of Pim-1, miR-195 and LUADT1 were detected by RT-qPCR. The interaction between miR-195 and LUADT1 was determined by overexpression experiments and luciferase activity assay. Cell apoptosis was detected by flow cytometry. The expression of apoptosis-related protein was detected by Western blotting. Results Bioinformatics analysis revealed the potential interaction between LUADT1 and miR-195, which was confirmed by dual luciferase reporter assay. LUADT1 was downregulated in patients with sepsis. Moreover, LPS treatment downregulated the expression of LUADT1 in primary cardiac endothelial cells. Overexpression of LUADT1 and miR-195 did not affect the expression of each other in primary cardiac endothelial cells. Interestingly, overexpression of LUADT1 was found to upregulate the expression of Pim-1, a target of miR-195. In addition, it was found that overexpression of LUADT1 and Pim-1 reduced the enhancement effects of miR-195 on LPS-induced cardiac endothelial cell apoptosis. Conclusion In summary, LUADT1 may protect cardiac endothelial cells against apoptosis in sepsis by regulating the miR-195/Pim-1 axis.


2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Paul T. King

Bronchiectasis is a prevalent respiratory condition characterised by permanent and abnormal dilation of the lung airways (bronchi). There are a large variety of causative factors that have been identified for bronchiectasis; all of these compromise the function of the immune response to fight infection. A triggering factor may lead to the establishment of chronic infection in the lower respiratory tract. The bacteria responsible for the lower respiratory tract infection are usually found as commensals in the upper respiratory tract microbiome. The consequent inflammatory response to infection is largely responsible for the pathology of this condition. Both innate and adaptive immune responses are activated. The literature has highlighted the central role of neutrophils in the pathogenesis of bronchiectasis. Proteases produced in the lung by the inflammatory response damage the airways and lead to the pathological dilation that is the pathognomonic feature of bronchiectasis. The small airways demonstrate infiltration with lymphoid follicles that may contribute to localised small airway obstruction. Despite aggressive treatment, most patients will have persistent disease. Manipulating the immune response in bronchiectasis may potentially have therapeutic potential.


2015 ◽  
Vol 396 (11) ◽  
pp. 1181-1197 ◽  
Author(s):  
Yi Wu ◽  
Lawrence A. Potempa ◽  
Driss El Kebir ◽  
János G. Filep

Abstract The prototypic acute-phase reactant C-reactive protein (CRP) has long been recognized as a useful marker and gauge of inflammation. CRP also plays an important role in host defense against invading pathogens as well as in inflammation. CRP consists of five identical subunits arranged as a cyclic pentamer. CRP exists in at least two conformationally distinct forms, i.e. native pentameric CRP (pCRP) and modified/monomeric CRP (mCRP). These isoforms bind to distinct receptors and lipid rafts, and exhibit distinct functional properties. Dissociation of pCRP into its subunits occurs within the inflammatory microenvironment and newly formed mCRP may then contribute to localizing the inflammatory response. Accumulating evidence indicates that pCRP possesses both pro- and anti-inflammatory actions in a context-dependent manner, whereas mCRP exerts potent pro-inflammatory actions on endothelial cells, endothelial progenitor cells, leukocytes and platelets, and thus may amplify inflammation. Here, we review recent advances that may explain how conformational changes in CRP contribute to shaping the inflammatory response and discuss CRP isomers as potential therapeutic targets to dampen inflammation.


2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Xianfeng Yan ◽  
Bin Xie ◽  
Guihai Wu ◽  
Jing Hu ◽  
Di Wang ◽  
...  

Interleukin-37 (IL-37) is unique in the IL-1 family since it broadly suppresses innate immunity and elevates in humans with inflammatory and autoimmune diseases. IL-37 shows definite groups and transcripts for human IL37 gene, but it is still not completely understood the effect and mechanisms of inflammatory response in endothelial cells. It is well accepted that endothelial dysfunction caused by inflammation is a key initiating event in atherosclerotic plaque formation, which leads to the occurrence and development of the cardiovascular adverse events in clinical since the inflammatory responses of endothelial cells could induce and enhance the deposition of extensive lipid and the formation of atherosclerotic plaque in the intima. Thus, it is essential to investigate the role and potential mechanisms in endothelial inflammatory response to prevent the formation and development of many cardiovascular diseases including atherosclerosis. So far, the recent studies have revealed that IL-37 is able to inhibit inflammatory response by suppressing the TLR2-NF-κB-ICAM-1 pathway intracellularly in human coronary artery endothelial cells (HCAECs). Further, the role of IL-37 may be related to the IL-18 pathway extracellularly and involved in the adhesion and transmigration of neutrophils in HCAECs.


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