Observing force-regulated conformational changes and ligand dissociation from a single integrin on cells

As adhesion molecules, integrins connect a cell to its environment and transduce signals across the membrane. Their different functional states correspond to distinct conformations. Using a biomembrane force probe, we observed real-time reversible switches between bent and extended conformations of a single integrin, αLβ2, on the surface of a living cell by measuring its nanometer-scale headpiece displacements, bending and unbending frequencies, and molecular stiffness changes. We determined the stabilities of these conformations, their dynamic equilibrium, speeds and rates of conformational changes, and the impact of divalent cations and tensile forces. We quantified how initial and subsequent conformations of αLβ2 regulate the force-dependent kinetics of dissociation from intercellular adhesion molecule 1. Our findings provide new insights into how integrins function as nanomachines to precisely control cell adhesion and signaling.

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Atherogenic Lipoprotein(a) Increases Vascular Glycolysis, Thereby Facilitating Inflammation and Leukocyte Extravasation

Circulation Research ◽

10.1161/circresaha.119.316206 ◽

2020 ◽

Vol 126 (10) ◽

pp. 1346-1359 ◽

Cited By ~ 12

Author(s):

Johan G. Schnitzler ◽

Renate M. Hoogeveen ◽

Lubna Ali ◽

Koen H.M. Prange ◽

Farahnaz Waissi ◽

...

Keyword(s):

Endothelial Cells ◽

Transendothelial Migration ◽

Intercellular Adhesion Molecule ◽

Phospholipid Content ◽

Intercellular Adhesion Molecule 1 ◽

Lipoprotein A ◽

Positron Emission ◽

And Migration ◽

The Impact ◽

Arterial Endothelial Cells

Rationale: Patients with elevated levels of lipoprotein(a) [Lp(a)] are hallmarked by increased metabolic activity in the arterial wall on positron emission tomography/computed tomography, indicative of a proinflammatory state. Objective: We hypothesized that Lp(a) induces endothelial cell inflammation by rewiring endothelial metabolism. Methods and Results: We evaluated the impact of Lp(a) on the endothelium and describe that Lp(a), through its oxidized phospholipid content, activates arterial endothelial cells, facilitating increased transendothelial migration of monocytes. Transcriptome analysis of Lp(a)-stimulated human arterial endothelial cells revealed upregulation of inflammatory pathways comprising monocyte adhesion and migration, coinciding with increased 6-phophofructo-2-kinase/fructose-2,6-biphosphatase (PFKFB)-3–mediated glycolysis. ICAM (intercellular adhesion molecule)-1 and PFKFB3 were also found to be upregulated in carotid plaques of patients with elevated levels of Lp(a). Inhibition of PFKFB3 abolished the inflammatory signature with concomitant attenuation of transendothelial migration. Conclusions: Collectively, our findings show that Lp(a) activates the endothelium by enhancing PFKFB3-mediated glycolysis, leading to a proadhesive state, which can be reversed by inhibition of glycolysis. These findings pave the way for therapeutic agents targeting metabolism aimed at reducing inflammation in patients with cardiovascular disease.

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Effect of Divalent Metal Ion on the Structure, Stability and Function of Klebsiella pneumoniae Nicotinate-Nucleotide Adenylyltransferase: Empirical and Computational Studies

International Journal of Molecular Sciences ◽

10.3390/ijms23010116 ◽

2021 ◽

Vol 23 (1) ◽

pp. 116

Author(s):

Olamide Jeje ◽

Reabetswe Maake ◽

Ruan van Deventer ◽

Veruschka Esau ◽

Emmanuel Amarachi Iwuchukwu ◽

...

Keyword(s):

Klebsiella Pneumoniae ◽

Conformational Changes ◽

Metal Ion ◽

Therapeutic Potential ◽

Divalent Cations ◽

Homology Modelling ◽

Substrate Binding ◽

Structure Stability ◽

Atp Binding ◽

The Impact

The continuous threat of drug-resistant Klebsiella pneumoniae justifies identifying novel targets and developing effective antibacterial agents. A potential target is nicotinate nucleotide adenylyltransferase (NNAT), an indispensable enzyme in the biosynthesis of the cell-dependent metabolite, NAD+. NNAT catalyses the adenylation of nicotinamide/nicotinate mononucleotide (NMN/NaMN), using ATP to form nicotinamide/nicotinate adenine dinucleotide (NAD+/NaAD). In addition, it employs divalent cations for co-substrate binding and catalysis and has a preference for different divalent cations. Here, the biophysical structure of NNAT from K. pneumoniae (KpNNAT) and the impact of divalent cations on its activity, conformational stability and substrate-binding are described using experimental and computational approaches. The experimental study was executed using an enzyme-coupled assay, far-UV circular dichroism, extrinsic fluorescence spectroscopy, and thermal shift assays, alongside homology modelling, molecular docking, and molecular dynamic simulation. The structure of KpNNAT revealed a predominately α-helical secondary structure content and a binding site that is partially hydrophobic. Its substrates ATP and NMN share the same binding pocket with similar affinity and exhibit an energetically favourable binding. KpNNAT showed maximum activity and minimal conformational changes with Mg2+ as a cofactor compared to Zn2+, Cu2+ and Ni2+. Overall, ATP binding affects KpNNAT dynamics, and the dynamics of ATP binding depend on the presence and type of divalent cation. The data obtained from this study would serve as a basis for further evaluation towards designing structure-based inhibitors with therapeutic potential.

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Identification of the binding site in intercellular adhesion molecule 1 for its receptor, leukocyte function-associated antigen 1.

Molecular Biology of the Cell ◽

10.1091/mbc.8.3.501 ◽

1997 ◽

Vol 8 (3) ◽

pp. 501-515 ◽

Cited By ~ 31

Author(s):

K L Fisher ◽

J Lu ◽

L Riddle ◽

K J Kim ◽

L G Presta ◽

...

Keyword(s):

Monoclonal Antibodies ◽

Binding Site ◽

Adhesion Molecule ◽

Inflammatory Responses ◽

Direct Interaction ◽

Intercellular Adhesion ◽

Intercellular Adhesion Molecule ◽

Lymphocyte Function ◽

Intercellular Adhesion Molecule 1 ◽

A Cell

Intercellular adhesion molecule 1 (ICAM-1, CD54) is a member of the Ig superfamily and is a counterreceptor for the beta 2 integrins: lymphocyte function-associated antigen 1 (LFA-1, CD11a/CD18), complement receptor 1 (MAC-1, CD11b/CD18), and p150,95 (CD11c/CD18). Binding of ICAM-1 to these receptors mediates leukocyte-adhesive functions in immune and inflammatory responses. In this report, we describe a cell-free assay using purified recombinant extracellular domains of LFA-1 and a dimeric immunoadhesin of ICAM-1. The binding of recombinant secreted LFA-1 to ICAM-1 is divalent cation dependent (Mg2+ and Mn2+ promote binding) and sensitive to inhibition by antibodies that block LFA-1-mediated cell adhesion, indicating that its conformation mimics that of LFA-1 on activated lymphocytes. We describe six novel anti-ICAM-1 monoclonal antibodies, two of which are function blocking. Thirty-five point mutants of the ICAM-1 immunoadhesin were generated and residues important for binding of monoclonal antibodies and purified LFA-1 were identified. Nineteen of these mutants bind recombinant LFA-1 equivalently to wild type. Sixteen mutants show a 66-2500-fold decrease in LFA-1 binding yet, with few exceptions, retain binding to the monoclonal antibodies. These mutants, along with modeling studies, define the LFA-1 binding site on ICAM-1 as residues E34, K39, M64, Y66, N68, and Q73, that are predicted to lie on the CDFG beta-sheet of the Ig fold. The mutant G32A also abrogates binding to LFA-1 while retaining binding to all of the antibodies, possibly indicating a direct interaction of this residue with LFA-1. These data have allowed the generation of a highly refined model of the LFA-1 binding site of ICAM-1.

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The impact of ICAM-1, CCL2 and TGM2 gene polymorphisms on differentiation syndrome in acute promyelocytic leukemia

BMC Cancer ◽

10.1186/s12885-021-07783-y ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Zahra Mohammadzadeh ◽

Azadeh Omidkhoda ◽

Bahram Chahardouli ◽

Ghazaleh Hoseinzadeh ◽

Kamran Ali Moghaddam ◽

...

Keyword(s):

Acute Promyelocytic Leukemia ◽

Promyelocytic Leukemia ◽

Intercellular Adhesion Molecule ◽

Inflammatory Factors ◽

Nucleotide Polymorphisms ◽

Intercellular Adhesion Molecule 1 ◽

Differentiated Cells ◽

All Trans Retinoic Acid ◽

Haplotypic Association ◽

The Impact

Abstract Background Although arsenic trioxide (ATO) and all-trans retinoic acid (ATRA) are well-tolerated and effective treatments for Acute Promyelocytic Leukemia (APL), Differentiation Syndrome (DS) is a lethal side effect in some patients. The pathogenesis of DS is complex and not well understood; however, it is considered as an inflammatory response due to cytokines release of differentiated cells. Moreover, adhesion molecules that are widely expressed on the surface of differentiated cells and gene expression changes of transglutaminase2 (TGM2) are mechanisms involved in the development of DS. The purpose of this study was to assess the association of single nucleotide polymorphisms (SNP) of Intercellular Adhesion Molecule-1 (ICAM-1), chemokine (C-C motif) ligand 2 (CCL2) and TGM2 as inflammatory factors with differentiation syndrome susceptibility. Methods DNA was extracted from 133 APL patients and 100 normal controls. Assessment according to the PETHEMA criteria revealed that 13.5% of these patients experienced differentiation syndrome. Tetra-ARMS PCR and PCR-RFLP were done to amplify DNA fragments in APL patients with and without DS. Then DNA sequencing was done to validate the results. SNPStats, SPSS and Finch TV were used to analyze the results. Results A significant correlation was found between rs4811528 in the TGM2 gene and differentiation syndrome susceptibility (P = 0.002, 95% CI = 1.74–18.81, OR = 5.72) while rs5498 in ICAM-1, rs1024611 in CCL2, and rs7270785 in TGM2 genes showed no correlation with differentiation syndrome. The G allele of rs7270785 and rs4811528 showed a haplotypic association with differentiation syndrome (P = 0.03, 95% CI = 1.13–13.86, OR = 3.96). Conclusions AA genotype of the TGM2 SNP (rs4811528) may be a risk factor for development of DS in patients with APL following the use of ATRA/ATO.

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The Impact of Uremic Toxicity Induced Inflammatory Response on the Cardiovascular Burden in Chronic Kidney Disease

Toxins ◽

10.3390/toxins10100384 ◽

2018 ◽

Vol 10 (10) ◽

pp. 384 ◽

Cited By ~ 12

Author(s):

Ligia Claro ◽

Andrea Moreno-Amaral ◽

Ana Gadotti ◽

Carla Dolenga ◽

Lia Nakao ◽

...

Keyword(s):

Chronic Kidney Disease ◽

Kidney Disease ◽

Adhesion Molecule ◽

Cardiovascular Response ◽

Total Mortality ◽

Inflammatory Biomarkers ◽

Intercellular Adhesion Molecule ◽

Uremic Toxin ◽

Intercellular Adhesion Molecule 1 ◽

The Impact

Uremic toxin (UT) retention in chronic kidney disease (CKD) affects biological systems. We aimed to identify the associations between UT, inflammatory biomarkers and biomarkers of the uremic cardiovascular response (BUCVR) and their impact on cardiovascular status as well as their roles as predictors of outcome in CKD patients. CKD patients stages 3, 4 and 5 (n = 67) were recruited and UT (indoxyl sulfate/IS, p-cresil sulfate/pCS and indole-3-acetic acid/IAA); inflammatory biomarkers [Interleukin-6 (IL-6), high sensitivity C reactive protein (hsCRP), monocyte chemoattractant protein-1 (MCP-1), soluble vascular adhesion molecule-1 (sVCAM-1), soluble intercellular adhesion molecule-1 (sICAM-1) and soluble Fas (sFas)] and BUCVRs [soluble CD36 (sCD36), soluble receptor for advanced glycation end products (sRAGE), fractalkine] was measured. Patients were followed for 5.2 years and all causes of death was used as the primary outcome. Artery segments collected at the moment of transplantation were used for the immunohistochemistry analysis in a separate cohort. Estimated glomerular filtration rate (eGFR), circulating UT, plasma biomarkers of systemic and vascular inflammation and BUCVR were strongly interrelated. Patients with plaque presented higher signs of UT-induced inflammation and arteries from CKD patients presented higher fractalkine receptor (CX3CR1) tissue expression. Circulating IS (p = 0.03), pCS (p = 0.007), IL-6 (p = 0.026), sFas (p = 0.001), sCD36 (p = 0.01) and fractalkine (p = 0.02) were independent predictors of total mortality risk in CKD patients. Our results reinforce the important role of uremic toxicity in the pathogenesis of cardiovascular disease (CVD) in CKD patients through an inflammatory pathway.

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THP-1 Monocytes Up-Regulate Intercellular Adhesion Molecule 1 in Response to Pneumolysin from Streptococcus pneumoniae

Infection and Immunity ◽

10.1128/iai.73.10.6493-6498.2005 ◽

2005 ◽

Vol 73 (10) ◽

pp. 6493-6498 ◽

Cited By ~ 32

Author(s):

Justin Thornton ◽

Larry S. McDaniel

Keyword(s):

Cell Adhesion ◽

Streptococcus Pneumoniae ◽

Adhesion Molecule ◽

Cell Adhesion Molecule ◽

Intercellular Adhesion ◽

Single Amino Acid ◽

Intercellular Adhesion Molecule ◽

Wild Type ◽

Intercellular Adhesion Molecule 1 ◽

A Cell

ABSTRACT Pneumolysin (PLY) is a major virulence factor of Streptococcus pneumoniae that elicits a variety of proinflammatory responses from cells of the host immune system. Intercellular adhesion molecule 1 (ICAM-1) is a cell adhesion molecule involved in leukocyte trafficking toward inflammatory stimuli in extravascular sites. In this study, we evaluated the effect of PLY on expression of ICAM-1 in THP-1 monocytic cells exposed to S. pneumoniae. Exposure of cells to PLY-expressing S. pneumoniae strain WU2 for 6 h led to significantly higher levels of ICAM-1 message than those in cells exposed to either medium alone or ΔPLY1, a PLY-negative isogenic mutant of WU2. Cells exposed to purified recombinant PLY also showed a dose-dependent increase in ICAM-1 mRNA compared to cells exposed to medium alone. Exposure to recombinant PLY containing a single amino acid substitution (Trp433→Phe) that decreases cytolytic activity did not increase ICAM-1 mRNA to levels seen with wild-type PLY. In addition, THP-1 cells exposed to wild-type strain WU2 or D39 had increased ICAM-1 on their surface compared to cells exposed to medium alone or their PLY-negative isogenic mutants ΔPLY1 and ΔPLY2, respectively. These data indicate that PLY induces transcription and production of a cell adhesion molecule involved in the inflammatory response that may play a role in pneumococcal infection.

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Butyrate Decreases ICAM-1 Expression in Human Oral Squamous Cell Carcinoma Cells

International Journal of Molecular Sciences ◽

10.3390/ijms21051679 ◽

2020 ◽

Vol 21 (5) ◽

pp. 1679 ◽

Cited By ~ 3

Author(s):

Gabriel Leonardo Magrin ◽

Francesca Di Summa ◽

Franz-Josef Strauss ◽

Layla Panahipour ◽

Michael Mildner ◽

...

Keyword(s):

Epithelial Cells ◽

Nuclear Translocation ◽

Trichostatin A ◽

Interleukin 1 ◽

Intercellular Adhesion Molecule ◽

Intercellular Adhesion Molecule 1 ◽

Oral Epithelial Cells ◽

Oral Squamous Carcinoma ◽

Oral Epithelial ◽

The Impact

Short-chain fatty acids (SCFA) are bacterial metabolites that can be found in periodontal pockets. The expression of adhesion molecules such as intercellular adhesion molecule-1 (ICAM-1) within the epithelium pocket is considered to be a key event for the selective transmigration of leucocytes towards the gingival sulcus. However, the impact of SCFA on ICAM-1 expression by oral epithelial cells remains unclear. We therefore exposed the oral squamous carcinoma cell line HSC-2, primary oral epithelial cells and human gingival fibroblasts to SCFA, namely acetate, propionate and butyrate, and stimulated with known inducers of ICAM-1 such as interleukin-1-beta (IL1β) and tumor necrosis factor-alfa (TNFα). We report here that butyrate but not acetate or propionate significantly suppressed the cytokine-induced ICAM-1 expression in HSC-2 epithelial cells and primary epithelial cells. The G-protein coupled receptor-43 (GPR43/ FFAR2) agonist but not the histone deacetylase inhibitor, trichostatin A, mimicked the butyrate effects. Butyrate also attenuated the nuclear translocation of p65 into the nucleus on HSC-2 cells. The decrease of ICAM-1 was independent of Nrf2/HO-1 signaling and phosphorylation of JNK and p38. Nevertheless, butyrate could not reverse an ongoing cytokine-induced ICAM-1 expression in HSC-2 cells. Overall, these observations suggest that butyrate can attenuate cytokine-induced ICAM-1 expression in cells with epithelial origin.

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The impact of selectins on mortality in stable carotid atherosclerosis

Thrombosis and Haemostasis ◽

10.1160/th14-12-1014 ◽

2015 ◽

Vol 114 (09) ◽

pp. 632-638 ◽

Cited By ~ 9

Author(s):

Matthias Hoke ◽

Max-Paul Winter ◽

Oswald Wagner ◽

Markus Exner ◽

Martin Schillinger ◽

...

Keyword(s):

Adhesion Molecule ◽

Cardiovascular Mortality ◽

Carotid Atherosclerosis ◽

Leukocyte Adhesion ◽

Inflammatory Cells ◽

Endothelial Activation ◽

Cellular Adhesion ◽

Intercellular Adhesion Molecule ◽

Intercellular Adhesion Molecule 1 ◽

The Impact

SummaryCellular adhesion molecules also known as selectins promote recruitment of inflammatory cells into the arterial wall where they interact with lipid particles leading subsequently to plaque formation. The intercellular adhesion molecule-1 (ICAM-1), the vascular cell adhesion molecule-1 (VCAM-1) and the endothelial-leukocyte adhesion molecule 1 (ELAM-1) also known as E-selectin mediate the attachment of leukocytes and have been implicated in the destabilisation of atherosclerotic plaques. Therefore, we hypothesised that plasma selectin levels are associated with adverse clinical outcome. We prospectively studied 855 patients with sonographically confirmed carotid atherosclerosis. During a median follow-up of 6.2 years, corresponding to 5,551 overall person-years, 275 patients (26 %) died. We detected a significant association between cardiovascular mortality and ICAM-1 (adjusted hazard ratio [HR]: 3.43, 95 % confidence interval [CI] 2.00–5.88, p< 0.001) as well as VCAM-1 (adjusted HR: 2.51, 95 % CI 1.45–4.34, p=0.001) when comparing the fourth with the first quartile. Comparable results were obtained for all-cause mortality. In contrast, we could not detect a significant association between E-selectin and all-cause or cardiovascular mortality. We identified the selectins ICAM-1 and VCAM-1 as strong and independent predictors of all-cause and cardiovascular mortality in patients with stable carotid atherosclerosis. These molecules are elevated in states of endothelial activation and might assist to monitor anti-atherosclerotic therapy and select those patients with carotid atherosclerosis, who are at higher risk for cardiovascular events.

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Behavior of Primary Human Oral Keratinocytes Grown on Invisalign® SmartTrack® Material

Applied Sciences ◽

10.3390/app11062826 ◽

2021 ◽

Vol 11 (6) ◽

pp. 2826

Author(s):

Michael Nemec ◽

Hans Magnus Bartholomaeus ◽

Christian Wehner ◽

Christian Behm ◽

Hassan Ali Shokoohi-Tabrizi ◽

...

Keyword(s):

Gene Expression ◽

Control Cell ◽

World Market ◽

Cell Counting ◽

Intercellular Adhesion Molecule ◽

Oral Keratinocytes ◽

Intercellular Adhesion Molecule 1 ◽

Cellular Effects ◽

Clear Aligner ◽

Cells Cultured

Orthodontic clear aligner treatment is gaining tremendous popularity. The world market leader is Align Technology® and its product Invisalign®. Although numerous patients are treated with Invisalign® aligners, only little is known about the cellular effects of aligner material on oral epithelial cells. In the present study, we aimed to investigate the effects of SmartTrack® clear aligner material on directly cultured primary human oral keratinocytes (HOKs). Cell morphology and behavior were investigated by scanning electron microscopy and bright field microscopy. Aligner effects on viability were detected by cell-counting-kit (CCK)-8 and live/dead staining. Gene expression of several inflammatory and barrier proteins was assessed by qPCR. Cells cultured on tissue culture plastic served as control. Cell proliferation/viability was significantly lower in cells cultured on aligner material (p < 0.05) in comparison to control. Live/dead staining did not reveal an increase in the number of dead cells on aligner surfaces. After two and seven days of incubation, interleukin (IL)-6 expression decreased, and IL-8 expression increased in HOKs cultured on aligner surfaces. The expression of intercellular adhesion molecule 1 (ICAM-1) significantly decreased after seven days. Gene expression of epithelial barrier markers showed that integrin (ITG)-α6 significantly decreased after two and seven days. A significant decrease in ITG-β4 and E-cadherin expression levels compared to control could only be seen after seven days. We did not find any cytotoxic effect, but alterations in the cell’s barrier functions and inflammatory reaction were obvious. Clinical studies are required to give further insights into clinical reactions on the underlying aligner material of this quickly expanding orthodontic appliance.

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