New α-Granule Biology Reveals How Platelets May Regulate Angiogenesis

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. SCI-35-SCI-35
Author(s):  
Joseph E. Italiano ◽  
Elisabeth M. Battinelli
Keyword(s):  
Molecular Basis ◽  
Conflicts Of Interest ◽  
Local Environment ◽  
Regulatory Proteins ◽  
Angiogenic Potential ◽  
Angiogenic Response ◽  
Filament Assembly ◽  
Activated Platelets ◽  
Vessel Growth ◽  
New Form

Abstract Abstract SCI-35 In addition to their “classic” role in hemostasis, platelets are now known to be major contributors in wound healing, tumor growth, and angiogenesis. Stored within the α-granules is an array of angiogenic regulatory proteins, which are deposited by the secretion reaction of surface-activated platelets into the local environment of a tumor or wound. Despite the recognized importance of platelets in regulating new blood vessel growth, our understanding of how platelets modulate the angiogenic response remains unclear. Here, we consider how new α-granule biology may provide insights into how platelets regulate angiogenesis. First, we will present data on a new form of α-granule movement. We will show that actin filament assembly can power the propulsion of α-granule movement, and this may be a novel mechanism underlying the secretion reaction. Second, we show that one mechanism by which anticoagulants may impact malignancy is by disrupting the tumor cells' ability to hijack the angiogenic potential of platelets. Third, we will review the molecular basis of transport and delivery of α-granules to assembling platelets. Finally, we will discuss the concept of using “designer platelets” as a drug delivery system for targeted agents. Disclosures: No relevant conflicts of interest to declare.

Anti-Coagulation Agents Provide a Mechanism to Inhibit Tumor Cells From Hijacking the Angiogenic Potential of Platelets

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 1149-1149
Author(s):  
Elisabeth M. Battinelli ◽  
Beth Markens ◽  
Joseph E. Italiano
Keyword(s):  
Blood Vessel ◽  
Cancer Patients ◽  
Tumor Cells ◽  
Conflicts Of Interest ◽  
Tumor Cell Line ◽  
Regulatory Proteins ◽  
Endothelial Cell Migration ◽  
Angiogenic Potential ◽  
Vessel Growth ◽  
Mcf 7

Abstract Abstract 1149 While an association between cancer and platelets has been long recognized, the cause and effect relationship linking the two remains unclear. Provocatively, recent studies suggest that anti-platelet agents can increase overall survival and decrease metastatic disease in cancer patients. Because angiogenesis is crucial for tumor growth beyond 1–2 mm3, one view is that platelets may regulate new blood vessel growth through release of the vast array of angiogenesis promoters and stimulators stored in platelet alpha granules. We previously demonstrated that physiological agonists as well as tumor cells (MCF-7 breast cancer cells) could direct the preferential release of pro-angiogenic regulatory proteins from platelets, providing a mechanism for how tumor cells may promote new blood vessel growth in the tumor microenvironment (Battinelli et. al Blood, 2011). In line with these observations, we recently showed that the pro-angiogenic potential of platelets could be attenuated by the anti-platelet agent aspirin providing one mechanism by which platelet inhibitors may attenuate metastatic spread. These observations motivated the hypothesis that agents with anti-thrombotic effects, including LMWH, may also alter the release of angiogenesis regulatory proteins from platelets. Our results reveal that platelets pretreated with daltaparin (a LMWH) showed significant decreases in the amount of VEGF released in response to activation by either the platelet agonist ADP (0.633+/−0.63 with dalteparin vs. 55.71+/−13.92 without dalteparin, p<0.05) or the MCF-7 tumor cell line (28.89+/−0.389 with dalteparin vs. 114.0+/− 38.38 without dalteparin, p<0.05). The angiogenic potential of the releasate generated from ADP was significantly decreased as measured by endothelial cell migration (81.25 +/− 8.6 without dalteparin and 0.5 +/− 0.2 with dalteparin). Similar results were observed for the releasate generated from MCF-7 cell exposure (106.6 +/− 14.7 without dalteparin and 2.33 +/− 0.8 with dalteparin). The angiogenic response of the releasate generated from ADP was also significantly decreased as measured by capillary tube formation assay (155.3 +/− 8.9 without dalteparin vs. 38.5 +/− 4.1 with dalteparin). Comparable results were observed for the releasate generated from MCF-7 cell exposure (138.5 +/− 10.6 without dalteparin vs. 23.00 +/− 5.0 with dalteparin). Other anti-coagulants including fondaparinux and unfractionated heparin also produced profound blockade of the platelet angiogenic potential. Taken together, these data underscore the pivotal role of platelets in regulating tumor angiogenesis. Attenuation of platelet angiogenic potential by anti-thrombotic agents may be a mechanism underlying their effects on the improved survival and the decreased metastasis in cancer patients. This study may provide a rationale to search for new cancer drugs by their effects on platelet-mediated angiogenic potential. Disclosures: No relevant conflicts of interest to declare.

Organization and Physiologically Mediated Differential Release of Angiogenic Regulatory Proteins From Distinct Platelet Alpha Granules.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 3045-3045
Author(s):  
Elisabeth Battinelli ◽  
Joseph Italiano
Keyword(s):  
Tumor Metastasis ◽  
Conflicts Of Interest ◽  
Human Platelets ◽  
Angiogenic Factors ◽  
Regulatory Proteins ◽  
Angiogenic Balance ◽  
Angiogenic Proteins ◽  
Vessel Growth ◽  
Proteinase Activated Receptors ◽  
Immunofluorescence Labeling

Abstract 3045 Poster Board II-1021 In addition to their primary roles in hemostasis and thrombosis, platelets have been reported to participate in other physiological and pathological processes, including but not limited to inflammation, wound healing, and tumor metastasis. Although platelets are presumed to contribute to new blood vessel growth by providing numerous pro-and anti-angiogenic factors, the cellular and molecular basis by which platelets regulate angiogenesis is poorly understood. Previously we have shown that platelets differentially package angiogenic regulatory proteins in their alpha granules. More recently, we have further defined the organization of angiogenic proteins within platelet alpha granules using immunofluorescence and immunogold labeling experiments and have uncovered at least three distinct types of alpha granules. These granules were found to contain selective members of pro- and anti-angiogenic regulatory proteins, respectively. In addition, we have analyzed platelets from nine patients with metastatic renal cell carcinoma using immunofluorescence labeling for VEGF and endostatin. In comparison to volunteer control platelets without known malignancy, there is a significant increase in granules containing VEGF in patients with metastatic disease, strongly suggesting a shift of the angiogenic balance towards a more pro-angiogenic environment in the platelets from patients with malignancy. Previously we have shown that differentially packaged alpha granules are susceptible to selective release in response to proteinase-activated receptors. To explore whether selective release also occurred in physiologic conditions, we activated human platelets with known platelet agonists and looked for evidence of selective release. We have demonstrated that differential release of VEGF can be physiologically regulated by activation with ADP. Human platelets exposed to 50uM ADP result in release of VEGF and retention of endostatin, both by immunofluorecence labeling and by ELISA assay. This study provides mechanistic evidence to support an interplay between tumor cells and platelets, by illustrating a key role for platelets in tumor angiogenesis through the delivery of specific angiogenic factors. This work has implications beyond basic platelet biology as it provides a model for the platelet as a delivery system, with important clinical implications. Disclosures No relevant conflicts of interest to declare.

scholarly journals The cryo-EM structure of the bacterial flagellum cap complex suggests a molecular mechanism for filament elongation

2019 ◽  
Author(s):  
Natalie S. Al-Otaibi ◽  
Aidan J. Taylor ◽  
Daniel P. Farrell ◽  
Svetomir B. Tzokov ◽  
Frank DiMaio ◽  
...  
Keyword(s):  
Molecular Mechanism ◽  
Campylobacter Jejuni ◽  
Bacterial Cell ◽  
Molecular Basis ◽  
Molecular Model ◽  
Molecular Motor ◽  
Terminal Region ◽  
Bacterial Flagellum ◽  
Filament Assembly ◽  
Oligomeric Assembly

AbstractThe bacterial flagellum is a remarkable molecular motor, present at the surface of many bacteria, whose primary function is to allow motility through the rotation of a long filament protruding from the bacterial cell. A cap complex, consisting of an oligomeric assembly of the protein FliD, is localized at the tip of the flagellum, and is essential for filament assembly, as well as adherence to surfaces in some bacteria. However, the structure of the intact cap complex, and the molecular basis for its interaction with the filament, remains elusive. Here we report the cryo-EM structure of the Campylobacter jejuni cap complex. This structure reveals that FliD is pentameric, with the N-terminal region of the protomer forming an unexpected extensive set of contacts across several subunits, that contribute to FliD oligomerization. We also demonstrate that the native C. jejuni flagellum filament is 11-stranded and propose a molecular model for the filament-cap interaction.

Two Alleles with RHCE*nt818C>T Change Encode the Low Prevalence Rh Antigen STEM.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 3159-3159 ◽  
Author(s):  
Christine Halter-Hipsky ◽  
Kim Hue-Roye ◽  
Gail Coghlan ◽  
Christine Lomas-Francis ◽  
Marion E. Reid
Keyword(s):  
South African ◽  
Molecular Basis ◽  
Index Case ◽  
Conflicts Of Interest ◽  
Direct Sequencing ◽  
Molecular Testing ◽  
Variable Expression ◽  
New Findings ◽  
Low Prevalence ◽  
Original Index

Abstract Abstract 3159 Poster Board III-96 Background According to the original (and only) report, the low prevalence Rh antigen, STEM, is associated with an altered e phenotype. Approximately 65% of hrS– and 30% of hrB– RBCs from South African donors are STEM+. STEM has a variable expression, which is an inherited characteristic. Anti-STEM has induced mild HDFN (Marais, et al., Transf Med 1993;3:35-41). The purpose of this study was to determine the molecular basis associated with STEM expression. Material and Methods Blood samples and reagents were from our collections. Hemagglutination and DNA extraction were performed by standard methods. Molecular testing included direct sequencing and cloning of cDNA, AS-PCR, PCR-FRLP, and sequencing specific exons of gDNA. Results Three STEM+ samples (including the original index case) had RHCE*ceBI [ce 48C (16C), 712G (238V), 818T (273V), 1132G (378V)] (Noizat-Pirenne, et al., Blood 2002;100:4223-31) and 6 had a new allele, which we name RHCE*ceSM (ce 48C, 712G, 818T). In contrast, 8 STEM– samples (which included hrS– and hrB– samples) did not have the RHCE*818C>T change. RBCs with the ceBI phenotype expressed STEM more strongly than those with the ceSM phenotype. Conclusions The previously reported allele RHCE*ceBI and a new allele, RHCE*ceSM, encode the STEM antigen. This study also revealed other new findings: (i) ceSM encodes a weaker expression of STEM than does ceBI, which explains the previously reported variable expression, (ii) provides an explanation for why not all hrS– and hrB– RBCs express STEM. RBCs with ceAR, ceMO, and ceEK, phenotypes are hrS– STEM–, and RBCs with ceS phenotypes type hrB–, STEM–, (iii) ceBI and ceSM do not express hrS but do express hrB. It is likely that anti-hrS made by hrS– STEM– people (ceAR, ceMO, ceEK) will be incompatible with hrS– STEM+ RBCs, and vice versa. Our findings provide a means to positively identify the STEM+ phenotypes, which, by hemagglutination, is virtually impossible due to the dearth of anti-STEM. Further, it provides a tool to provide suitable antigen-negative RBC products to a patient who has made an ‘e-like’ antibody. Disclosures No relevant conflicts of interest to declare.

Iron Regulatory Proteins in Systemic Iron Metabolism and Erythropoiesis

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. SCI-22-SCI-22
Author(s):  
Matthias W. Hentze
Keyword(s):  
Iron Metabolism ◽  
Iron Homeostasis ◽  
Mutant Mouse ◽  
Conflicts Of Interest ◽  
Regulatory Proteins ◽  
Iron Regulatory Proteins ◽  
Cellular Iron ◽  
Regulatory Systems ◽  
Biology I ◽  
Mouse Lines

Abstract Abstract SCI-22 Imbalances of iron homeostasis account for some of the most common human diseases. Pathologies can result from both iron deficiency or overload. The hepcidin/ferroportin and the IRE/IRP regulatory systems balance systemic and cellular iron metabolism, respectively, and understanding their points of intersection and crosstalk represents a major challenge in iron biology. I will discuss an emerging picture from studies with different mutant mouse lines according to which the “cellular” IRE/IRP system determines “set points” via its targets (including ferroportin and HIF2α). These are then subject to modulation via hepcidin in response to systemic cues. Disclosures: No relevant conflicts of interest to declare.

Inhibition of Platelet-Prothrombianse by a Covalent Antithrombin-Heparin Complex.

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 2212-2212
Author(s):  
Ivan Stevic ◽  
Howard H.W. Chan ◽  
Ankush Chander ◽  
Leslie R. Berry ◽  
Anthony K.C. Chan
Keyword(s):  
Thrombin Generation ◽  
Conflicts Of Interest ◽  
Anticoagulant Activity ◽  
Calcium Ionophore ◽  
Thrombin Inhibitor ◽  
Ionophore A23187 ◽  
Specific Substrate ◽  
Prothrombinase Complex ◽  
Activated Platelets

Abstract Abstract 2212 Introduction: Factor Xa is protected within the prothrombinase complex from inhibition by heparin. We have developed a covalent antithrombin-heparin complex (ATH) with enhanced anticoagulant activity. Previously, we have shown that ATH is able to inhibit coagulation enzymes much more efficiently than regular antithrombin+heparin (AT+UFH). For example, ATH inhibited TF/VIIa ∼30-fold faster compared to AT+UFH. Furthermore, we have also demonstrated that ATH is capable of inhibiting Xa within a prothrombinase complex assembled on synthetic phospholipid vesicles better than AT+UFH. However, ATH's effect on prothrombinase when the complex is formed on a more native system such as platelets has never been explored. Thus, the objective of the present study is to determine the ability of ATH vs AT+UFH to inhibit Xa within the prothrombinase complex when the enzyme complex is assembled on the platelet system. Methods: Discontinuous second order rate constant assays were performed to obtain k2-values for inhibition of free or prothrombinase-bound Xa by AT+UFH or ATH. Freshly prepared resting platelets were subjected to inhibition analysis by first incubating them with Xa, Va, Ca2+ and pefabloc®-TH (thrombin inhibitor) in different wells of a 96-well plate for 3 min at 37 °C. Prothrombin was then simultaneously added to all wells to initiate thrombin generation, followed by addition of AT+UFH or ATH inhibitors to each well at specific time intervals. Reactions were neutralized by simultaneous addition of polybrene, Na2EDTA and Xa-specific substrate S-2222™ in buffer. The remaining Xa enzyme activity was obtained and final k2-values calculated. For experiments requiring activated platelets, freshly isolated platelets were activated with 5 μM calcium ionophore A23187 + 4 mM CaCl2 for 15 min at room temperature. The activated platelets were then tested in inhibition assays as described above. To investigate the roles of individual components of the prothrombinase complex on the anticoagulant effects of AT+UFH and ATH, additional experiments were performed where components of the complex (prothrombin, activated platelets or Va) were omitted prior to reaction with inhibitors. Thrombin generation was used to assess functionality of the activated platelet-prothrombinase system in the presence of inhibitors using a thrombin-specific substrate S-2238™. Results: The k2-values (×108M−1min−1) for inhibition of free Xa or resting platelet-prothrombinase were similar for both inhibitors, although the overall inhibition rates achieved by the ATH were 2-fold faster than AT+UFH (p<0.001). Since activated platelets are required for enhanced prothrombinase function, we then compared inhibition of free vs activated platelet-prothrombinase by the two inhibitors (platelet activation was confirmed with flow cytometry using an anti CD-41 antibody). No differences were observed in the k2-values between free Xa (3.96±0.23) and activated platelet prothrombinase (3.83±0.39) for ATH reactions. However, the k2-values for inhibition of free Xa by AT+UFH was 2.37±0.32, and assembly of Xa within the activated platelet-prothrombinase resulted in a reduction in the k2-values to 0.99±0.22 (p<0.001), thus confirming a moderate 60% protection of Xa by the prothrombinase components. However, omitting the components (prothrombin, activated platelets or Va) from the complex resulted in higher k2-values (1.76±0.37, 2.29±0.26 and 2.52±0.32, respectively p<0.01) for AT+UFH, and as expected, no net effect was observed for ATH. Thrombin generation was inhibited significantly by both AT+UFH and ATH compared to the control (p<0.001), but further analysis of thrombin potential yielded greater inhibition by ATH compared to AT+UFH (p<0.05). Conclusion: In this study, we report inhibition of the prothrombinase complex on the surface of resting and activated platelets. Consistent with previous investigations, a moderate protection of Xa was observed when the activated platelet-prothrombinase was inhibited by AT+UFH. ATH on the other hand, targets and inhibits prothrombinase complexed-Xa as fast as free Xa, and at inhibition rates that were significantly faster than AT+UFH. Thus, overall the covalent conjugate enhances anticoagulation of surface-bound enzymes and offers advantages over conventional heparin for the treatment of cell-based coagulation in vivo. Disclosures: No relevant conflicts of interest to declare.

Platelets Protect From Lipopolysaccharide-Induced Lethal Endotoxemia by Inhibiting Macrophage-Dependent Inflammation Via the Cyclooxygenase 1 (COX1) Signaling Pathway

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 93-93
Author(s):  
Binggang Xiang ◽  
Guoying Zhang ◽  
Xiang-An Li ◽  
Andrew J. Morris ◽  
Alan Daugherty ◽  
...  
Keyword(s):  
Septic Shock ◽  
Platelet Transfusion ◽  
Conflicts Of Interest ◽  
Plasma Concentrations ◽  
Platelet Inhibition ◽  
Severe Thrombocytopenia ◽  
Wild Type ◽  
Activated Platelets ◽  
Platelet Depletion

Abstract Abstract 93 Sepsis is a tremendous burden for health-care systems. Patients with sepsis often have low platelet counts, and septic patients with severe thrombocytopenia have a poor prognosis and higher mortality. However, the role of platelets in the pathogenesis of sepsis has not been well elucidated. We investigated the role of platelets in septic shock using a mouse model of lipopolysaccharide (LPS)-induced endotoxemia. Depletion of platelets by intraperitoneal injection of a rat anti-mouse GPIb monoclonal antibody increased mortality and aggravated organ failure in endotoxemic mice as evident by increases in plasma aminotransferase (ALT), aspartate aminotransferase (AST), Lactate dehydrogenase (LDH), and Creatine kinase (CK) concentrations, while transfusion of platelets reduced mortality. Increases in mortality rate in thrombocytopenic mice by LPS challenge was not due to inflammatory hemorrhage, because there was no significantly hemorrhage observed in brains and lungs from mice pre-treated with either control IgG or the anti-GPIba antibody and blood RBC and Hb concentrations between IgG pre-treated mice and the anti-GPIba antibody pre-treated mice were similar. TNF-a, which is produced mainly by macrophages in vivo, plays critical roles in the development of disseminated intravascular coagulation, acute respiratory distress syndrome and shock in sepsis. Our data indicate that plasma concentrations of proinflammatory cytokines, TNF-a and IL-6, were markedly increased by platelet depletion and decreased by platelet transfusion in the mice challenged with LPS. Effects of platelet depletion on TNF-a production were eliminated in the mice that macrophages were pre-depleted. Furthermore, LPS- or thrombin-activated platelets or releasates from activated platelets inhibited TNF-a and IL-6 production in macrophages in vitro. Inhibition of TNF-a and IL-6 production in macrophages by activated platelets was prevented by pre-incubation of platelets with a COX1 inhibitor aspirin. Moreover, platelets from wild type mice but not COX1 deficient mice inhibited LPS-induced TNF-a and IL-6 production in macrophages. Transfusion of COX1 deficient platelets failed to protect against endotoxemia. Washed platelets from wild-type mice or platelet releasates from thrombin-activated wild-type mice inhibited LPS-induced TNF-a and IL-6 production in macrophages lacking TXA2 receptor, TP, suggesting that a metabolite other than TXA2 is responsible for platelet inhibition of macrophage function. We found that stimulation of platelets with thrombin or LPS induced PGE2 production and pre-incubation of macrophages with an antagonist of PGE2 receptor EP4 reversed platelet inhibition on TNF-a and IL-6 production in macrophages. Our results indicate that platelets protect against septic shock by inhibiting macrophage-dependent inflammatory response via the COX1/PGE2/EP4 dependent pathway. Thus, these findings demonstrate a previously unappreciated role for platelets in septic shock and suggest that platelet transfusion may be effective in treating septic patients. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Characterization of Patients with Glanzmann Thrombasthenia and Identification of 17 Novel Mutations

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 1460-1460
Author(s):  
Kirstin Sandrock-Lang ◽  
Johannes Oldenburg ◽  
Verena Wiegering ◽  
Susan Halimeh ◽  
Sentot Santoso ◽  
...  
Keyword(s):  
Conflicts Of Interest ◽  
Regulatory Element ◽  
Molecular Genetic ◽  
Compound Heterozygous ◽  
Glanzmann Thrombasthenia ◽  
Platelet Protein ◽  
Activated Platelets ◽  
Platelet Spreading ◽  
Willebrand Factor

Abstract Background: Glanzmann thrombasthenia (GT) is an autosomal recessive bleeding disorder. Platelets from patients with GT show quantitative and/or qualitative defects of the platelet membrane glycoprotein (GP) IIb/IIIa complex, also called integrin αIIbβ3. On activated platelets the αIIbβ3 binds von fibrinogen and Willebrand factor which leads to platelet spreading and formation of platelet-platelet protein bridges. Patients: In this study, 18 patients with GT were investigated with molecular genetic analyses. The patients presented with bleeding symptoms such as epistaxis, mucocutaneous bleeding, haematomas, petechiae, gastrointestinal bleeding, and menorrhagia. Methods and Results: As cause of GT in the patients homozygous or compound heterozygous mutations in ITGA2B or ITGB3 were identified through sequencing of genomic DNA. All exons including exon/intron boundaries of both genes were analyzed. In summary, 16 of 18 patients revealed 27 different mutations (ITGA2B: n = 17, ITGB3: n = 10). Of these mutations, 17 have not been published yet. Conclusion: In 16 patients mutations in ITGA2B or ITGB3 were identified as cause of GT. A total of 27 mutations including 17 novel missense, nonsense, frameshift and splice site mutations were detected. None of these mutations were present more than once in unrelated patients. In addition, 2 patients were without molecular genetic findings in ITGA2B or ITGB3 that could explain the suspected diagnosis of GT. We hypothesize that these patients may harbour defects in a regulatory element affecting the transcription of these genes or there may exist other proteins important for the activation of the αIIbβ3 complex that could be affected. Disclosures No relevant conflicts of interest to declare.

scholarly journals Biophysical properties governing septin assembly

2021 ◽  
Author(s):  
Benjamin L Woods ◽  
Ian L Seim ◽  
Jessica Liu ◽  
Grace McLaughlin ◽  
Kevin S. Cannon ◽  
...  
Keyword(s):  
Physical Model ◽  
Yeast Extract ◽  
Cell Membranes ◽  
Regulatory Proteins ◽  
Biophysical Properties ◽  
Regulatory Mutants ◽  
Filament Assembly ◽  
Pure Protein ◽  
Crowded Environments ◽  
Septin Filament

Septin filaments build structures such as rings, lattices and gauzes that serve as platforms for localizing signaling and organizing cell membranes. How cells control the geometry of septin assemblies in poorly understood. We show here that septins are isodesmic polymers, in contrast to cooperative polymerization exhibited by F-actin and microtubules. We constructed a physical model to analyze and interpret how septin assemblies change in the presence of regulators in yeast extracts. Notably filaments differ in length and curvature in yeast extract compared to pure protein indicating cellular regulators modulate intrinsic biophysical features. Combining analysis of extracts from regulatory mutants with simulations, we found increased filament flexibility and reduced filament fragmentation promote assembly of septin rings, whereas reduced flexibility in crowded environments promotes local filament alignment. This work demonstrates how tuning of intrinsic features of septin filament assembly by regulatory proteins yields a diverse array of structures observed in cells.

scholarly journals Transcriptional and Metabolomic Analysis of L-Arginine/Nitric Oxide Pathway in Inflammatory Bowel Disease and Its Association with Local Inflammatory and Angiogenic Response: Preliminary Findings

2020 ◽  
Vol 21 (5) ◽  
pp. 1641 ◽  
Author(s):  
Małgorzata Krzystek-Korpacka ◽  
Mariusz G. Fleszar ◽  
Iwona Bednarz-Misa ◽  
Łukasz Lewandowski ◽  
Izabela Szczuka ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Small Bowel ◽  
Metabolomic Analysis ◽  
Symmetric Dimethylarginine ◽  
Dimethylarginine Dimethylaminohydrolase ◽  
Angiogenic Potential ◽  
Angiogenic Response ◽  
Inflammatory Bowel ◽  
Irritable Bowel ◽  
Nitric Oxide Pathway

L-arginine/nitric oxide pathway in Crohn’s disease (CD) and ulcerative colitis (UC) is poorly investigated. The aim of current study is to quantify pathway serum metabolites in 52 CD (40 active), 48 UC (33 active), and 18 irritable bowel syndrome patients and 40 controls using mass spectrometry and at determining mRNA expression of pathway-associated enzymes in 91 bowel samples. Arginine and symmetric dimethylarginine decreased (p < 0.05) in active-CD (129 and 0.437 µM) compared to controls (157 and 0.494 µM) and active-UC (164 and 0.52 µM). Citrulline and dimethylamine increased (p < 0.05) in active-CD (68.7 and 70.9 µM) and active-UC (65.9 and 73.9 µM) compared to controls (42.7 and 50.4 µM). Compared to normal, CD-inflamed small bowel had downregulated (p < 0.05) arginase-2 by 2.4-fold and upregulated dimethylarginine dimethylaminohydrolase (DDAH)-2 (1.5-fold) and arginine N-methyltransferase (PRMT)-2 (1.6-fold). Quiescent-CD small bowel had upregulated (p < 0.05) arginase-2 (1.8-fold), DDAH1 (2.9-fold), DDAH2 (1.5-fold), PRMT1 (1.5-fold), PRMT2 (1.7-fold), and PRMT5 (1.4-fold). Pathway enzymes were upregulated in CD-inflamed/quiescent and UC-inflamed colon as compared to normal. Compared to inflamed, quiescent CD-colon had upregulated DDAH1 (5.7-fold) and ornithine decarboxylase (1.6-fold). Concluding, the pathway is deregulated in CD and UC, also in quiescent bowel, reflecting inflammation severity and angiogenic potential. Functional analysis of PRMTs and DDAHs as potential targets for therapy is warranted.

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