Hemodynamic forces regulate vascular functions. Disturbed flow (DF) occurs in arterial bifurcations and curvatures, activates endothelial cells (ECs), and results in vascular inflammation and ultimately atherosclerosis. However, how DF alters EC metabolism, and whether resulting metabolic changes induce EC activation, is unknown. Using transcriptomics and bioenergetic analysis, we discovered that DF induces glycolysis and reduces mitochondrial respiratory capacity in human aortic ECs. DF-induced metabolic reprogramming required hypoxia inducible factor-1α (HIF-1α), downstream of NAD(P)H oxidase-4 (NOX4)-derived reactive oxygen species (ROS). HIF-1α increased glycolytic enzymes and pyruvate dehydrogenase kinase-1 (PDK-1), which reduces mitochondrial respiratory capacity. Swine aortic arch endothelia exhibited elevated ROS, NOX4, HIF-1α, and glycolytic enzyme and PDK1 expression, suggesting that DF leads to metabolic reprogramming in vivo. Inhibition of glycolysis reduced inflammation suggesting a causal relationship between flow-induced metabolic changes and EC activation. These findings highlight a previously uncharacterized role for flow-induced metabolic reprogramming and inflammation in ECs.DOI: http://dx.doi.org/10.7554/eLife.25217.001

IntroductionSeptic shock syndrome resulting from excessive host immune responses induced by infectious organisms is a leading cause of death in hospitalized patients. [1][2][3] Pathophysiologic changes in sepsis involve the pathogen-induced uncontrolled release from immune cells, particularly monocytes and macrophages, of proinflammatory mediators. 4 Gram-negative bacterial infection is one of the major causes of systemic bacterial sepsis. 5 Lipopolysaccharide (LPS), a constituent of the Gram-negative outer membrane, is the leading cause of sepsis. LPS induces a rapid increase of proinflammatory mediators, leading to lethal systemic tissue damage and multiple organ failure, which mimics the inflammatory responses of septic syndrome. 6 In mammals, membrane-bound CD14 and toll-like receptor 4 (TLR4)-MD-2 participate in cellular recognition of LPS. 7 Binding of LPS to TLR4 triggers the activation of members of the mitogen-activated protein kinase (MAPK) pathway including p38, p42/p44 extracellular signal-regulated kinase (ERK1/2), and c-Jun N-terminal kinase (JNK). 8 In resting unstimulated cells, nuclear factor-B (NF-B), a heterodimeric complex composed of 50-and 65-kDa (p50/p65) protein subunits, 9 retains as an inactive complex bound to inhibitory B␣ (IB␣) in the cytoplasm. While the cells are under proinflammatory stimulation by LPS, phosphorylation and degradation of IB␣ permit NF-B nuclear translocation and promote the expression of inflammatory genes including inducible nitric oxide synthase (iNOS), tumor necrosis factor-␣ (TNF-␣), and others. 9Thrombomodulin (TM) is a 557 amino acid type I glycosylated transmembrane protein 10 with an NH 2 -terminal lectinlike region (domain 1; D1) followed by 6 epidermal growth factor (EGF)-like structures (domain 2; D2), an O-glycosylation site-rich domain (domain 3; D3), a transmembrane domain (domain 4; D4), and a cytoplasmic tail domain (domain 5; D5). TM domain 2 (TMD2) EGF-like structures are responsible for the anticoagulant activity of TM via the alteration of thrombin substrate specificity. TMD2-thrombin complex sequentially activates anticoagulant protein C inactivating procoagulant cofactors Va and VIIIa. 11 TM expression also occurs in keratinocytes, 12 polymorphonuclear neutrophils (PMNs), 13 monocytes, 14 and endothelial cells, 15 indicating additional functions of TM besides anticoagulation. 16 Indeed TM domains function as an adhesion molecule, 17 an angiogenic factor, 18 and an anti-inflammatory agent through protein C-dependent and -independent mechanisms. 16,19 Recently, anti-inflammatory activity of TM domain 1 (TMD1) was implied by observing that mice with a deleted TM lectinlike domain (TM LeD/LeD ) become more sensitive to LPS challenge through the suppressed expression of adhesion molecules via NFB and MAPK signaling pathways. 20 Moreover, mice with a mutation in the TM gene (TM pro/pro ) strongly reduce the capacity to generate activated protein C, an anti-inflammatory agent in treatment of sepsis. 21 Mice harboring the latter mutation display an u...

Tumor endothelial marker 1 (TEM1), also named endosialin and CD248, is a type I transmembrane glycoprotein containing a C‐type lectin‐like domain. TEM1 is highly expressed on tumor‐associated fibroblasts, stromal cells, pericytes, and dermal fibroblasts. Dermal fibroblasts play a pivotal role in cutaneous wound healing which occurs in three dynamic and overlapping but distinct stages, including inflammatory phase, proliferation phase, and remodeling phase. However, the physiological function of TEM1 in wound healing is still unknown. In wound healing process both TEM1 and platelet‐derived growth factor receptor α (PDGFRα) expressions were highly upregulated in myofibroblasts. The cell activation, proliferation, and collagen deposition in granulation tissues were decreased and slower wound healing was found in TEM1‐deleted mice. In addition, the cell migration, adhesion and proliferation in NIH3T3 cells were decreased when TEM1 expression was knockdown by shRNA. The downstream signaling, mitogenic, and chemoattractive effects of platelet‐derived growth factor‐BB‐treated NIH3T3 cells were inhibited by knockdown of TEM1. TEM1 and PDGFRα were co‐localized in sub‐cellular organelles in fibroblasts and could be co‐immunoprecepitated. Based on these results we proposed that TEM1 in combination with PDGFRα plays a critical role in wound healing by enhancing the mitogenic and chemoattractive effects of platelet‐derived growth factor‐BB and collagen deposition in myofibroblasts. Support or Funding Information This work was supported by a grant from the Ministry of Science and Technology, Executive Yuan, Taiwan. (MOST 105‐2320‐B‐006 ‐039 ‐MY3 to Hua‐Lin Wu) This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Monocyte chemoattractant protein-1 (MCP-1) stimulates the migration of monocytes to inflammatory sites, leading to the progression of many diseases. Recently, we described a monocyte-targeting peptide amphiphile micelle (MCP-1 PAM) incorporated with the chemokine receptor CCR2 binding motif of MCP-1, which has a high affinity for monocytes in atherosclerotic plaques. We further report here the biomimetic components of MCP-1 PAMs and the influence of the nanoparticle upon binding to monocytes. We report that MCP-1 PAMs have enhanced secondary structure compared to the MCP-1 peptide. As a result, MCP-1 PAMs displayed improved binding and chemoattractant properties to monocytes, which upregulated the inflammatory signaling pathways responsible for monocyte migration. Interestingly, when MCP-1 PAMs were incubated in the presence of prostate cancer cells in vitro, the particle displayed anticancer efficacy by reducing CCR2 expression. Given that monocytes play an important role in tumor cell migration and invasion, our results demonstrate that PAMs can improve the native biofunctional properties of the peptide and may be used as an effective inhibitor to prevent chemokine–receptor interactions that promote disease progression.

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