Evitar (l-Alanyl-l-Glutamine) Regulates Key Signaling Molecules in the Pathogenesis of Postoperative Tissue Fibrosis

2018 ◽  
Vol 26 (6) ◽  
pp. 724-733 ◽  
Author(s):  
Lynne M. Robertson ◽  
Nicole M. Fletcher ◽  
Michael P. Diamond ◽  
Ghassan M. Saed
Keyword(s):  
Cellular Response ◽  
Type I Collagen ◽  
Primary Cultures ◽  
Hypoxia Inducible Factor ◽  
Enzyme Linked Immunosorbent Assay ◽  
Type I ◽  
Dependent Manner ◽  
Tissue Fibrosis ◽  
Hypoxia Inducible Factor 1Α ◽  
Episodic Hypoxia

Aims:Hypoxia and the resulting oxidative stress play a major role in postoperative tissue fibrosis. The objective of this study was to determine the effect of l-alanyl-l-glutamine (Ala-Gln) on key markers of postoperative tissue fibrosis: hypoxia-inducible factor (HIF) 1α and type I collagen.Methods:Primary cultures of human normal peritoneal fibroblasts (NPF) established from normal peritoneal tissue were treated with increasing doses of Ala-Gln (0, 1, 2, or 10 mM) with hypoxia ([2% O2] 0-48 hours; continuous hypoxia) or after hypoxia (0.5, 1, 2, 4 hours) and restoration of normoxia (episodic hypoxia) with immediate treatment with Ala-Gln. Hypoxia-inducible factor 1α and type 1 collagen levels were determined by enzyme-linked immunosorbent assay. Data were analyzed with 1-way analysis of variance followed by Tukey tests with Bonferroni correction.Results:Hypoxia-inducible factor 1α and type I collagen levels increased in untreated controls by 3- to 4-fold in response to continuous and episodic hypoxia in human NPF. Under continuous hypoxia, HIF-1α and type I collagen levels were suppressed by Ala-Gln in a dose-dependent manner. l-alanyl-l-glutamine treatment after episodic hypoxia also suppressed HIF-1α and type I collagen levels for up to 24 hours for all doses and up to 48 hours at the highest dose, regardless of exposure time to hypoxia.Conclusions:l-alanyl-l-glutamine significantly suppressed hypoxia-induced levels of key tissue fibrosis (adhesion) phenotype markers under conditions of continuous as well as episodic hypoxia in vitro. This effect of glutamine on molecular events involved in the cellular response to insult or injury suggests potential therapeutic value for glutamine in the prevention of postoperative tissue fibrosis.

scholarly journals Binding of Brucella protein, Bp26, to select extracellular matrix molecules

2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Yasmin ElTahir ◽  
Amna Al-Araimi ◽  
Remya R. Nair ◽  
Kaija J. Autio ◽  
Hongmin Tu ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Type I Collagen ◽  
Host Cells ◽  
Mouse Serum ◽  
Enzyme Linked Immunosorbent Assay ◽  
Target Cells ◽  
Type I ◽  
Dependent Manner ◽  
Biolayer Interferometry

Abstract Background Brucella is a facultative intracellular pathogen responsible for zoonotic disease brucellosis. Little is known about the molecular basis of Brucella adherence to host cells. In the present study, the possible role of Bp26 protein as an adhesin was explored. The ability of Brucella protein Bp26 to bind to extracellular matrix (ECM) proteins was determined by enzyme-linked immunosorbent assay (ELISA) and biolayer interferometry (BLI). Results ELISA experiments showed that Bp26 bound in a dose-dependent manner to both immobilized type I collagen and vitronectin. Bp26 bound weakly to soluble fibronectin but did not bind to immobilized fibronectin. No binding to laminin was detected. Biolayer interferometry showed high binding affinity of Bp26 to immobilized type I collagen and no binding to fibronectin or laminin. Mapping of Bp26 antigenic epitopes by biotinylated overlapping peptides spanning the entire sequence of Bp26 using anti Bp26 mouse serum led to the identification of five linear epitopes. Collagen and vitronectin bound to peptides from several regions of Bp26, with many of the binding sites for the ligands overlapping. The strongest binding for anti-Bp26 mouse serum, collagen and vitronectin was to the peptides at the C-terminus of Bp26. Fibronectin did not bind to any of the peptides, although it bound to the whole Bp26 protein. Conclusions Our results highlight the possible role of Bp26 protein in the adhesion process of Brucella to host cells through ECM components. This study revealed that Bp26 binds to both immobilized and soluble type I collagen and vitronectin. It also binds to soluble but not immobilized fibronectin. However, Bp26 does not bind to laminin. These are novel findings that offer insight into understanding the interplay between Brucella and host target cells, which may aid in future identification of a new target for diagnosis and/or vaccine development and prevention of brucellosis.

scholarly journals Reduced liver fibrosis in hypoxia-inducible factor-1α-deficient mice

2009 ◽  
Vol 296 (3) ◽  
pp. G582-G592 ◽  
Author(s):  
Jeon-OK Moon ◽  
Timothy P. Welch ◽  
Frank J. Gonzalez ◽  
Bryan L. Copple
Keyword(s):  
Liver Fibrosis ◽  
Type I Collagen ◽  
Smooth Muscle Actin ◽  
Hypoxia Inducible Factor ◽  
Type I ◽  
Mrna Levels ◽  
Chronic Injury ◽  
Hypoxia Inducible Factor 1Α ◽  
Duct Ligation ◽  
Deficient Mice

Liver fibrosis is characterized by excessive deposition of extracellular matrix in the liver during chronic injury. During early stages of this disease, cells begin to synthesize and secrete profibrotic proteins that stimulate matrix production and inhibit matrix degradation. Although it is clear that these proteins are important for development of fibrosis, what remains unknown is the mechanism by which chronic liver injury stimulates their production. In the present study, the hypothesis was tested that hypoxia-inducible factor-1α (HIF-1α) is activated in the liver during chronic injury and regulates expression of profibrotic proteins. To investigate this hypothesis, mice were subjected to bile duct ligation (BDL), an animal model of liver fibrosis. HIF-1α protein was increased in the livers of mice subjected to BDL by 3 days after surgery. To test the hypothesis that HIF-1α is required for the development of fibrosis, control and HIF-1α-deficient mice were subjected to BDL. Levels of type I collagen and α-smooth muscle actin mRNA and protein were increased in control mice by 14 days after BDL. These levels were significantly reduced in HIF-1α-deficient mice. Next, the levels of several profibrotic mediators were measured to elucidate the mechanism by which HIF-1α promotes liver fibrosis. Platelet-derived growth factor (PDGF)-A, PDGF-B, and plasminogen activator inhibitor-1 mRNA levels were increased to a greater extent in control mice subjected to BDL compared with HIF-1α-deficient mice at 7 and 14 days after BDL. Results from these studies suggest that HIF-1α is a critical regulator of profibrotic mediator production during the development of liver fibrosis.

scholarly journals Gujiansan Ameliorates Avascular Necrosis of the Femoral Head by Regulating Autophagy via the HIF-1α/BNIP3 Pathway

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Jie Han ◽  
Yuan Chai ◽  
Xiao-yun Zhang ◽  
Feng Chen ◽  
Zhi-wei Xu ◽  
...  
Keyword(s):  
Femoral Head ◽  
Avascular Necrosis ◽  
Rat Model ◽  
Type I Collagen ◽  
Hypoxia Inducible Factor ◽  
Time Dependent ◽  
Tartrate Resistant Acid Phosphatase ◽  
Type I ◽  
Dependent Manner ◽  
Bone Specific Alkaline Phosphatase

Background. Clinically, the traditional Chinese medicine compound Gujiansan has been widely used in the treatment of steroid-induced avascular necrosis of the femoral head (SANFH). The present study aimed to investigate the mechanisms underlying the therapeutic effect of Gujiansan. Methods. A rat model of SANFH was established by the injection of dexamethasone (DEX) at a high dosage of 25 mg/kg/d. Then, Gujiansan was intragastrically administered for 2 weeks, 4 weeks, and 8 weeks, and histological examination of the femoral head was performed. The expression levels of related mRNAs and proteins were analyzed by qRT-PCR, Western blotting, and immunohistochemistry, and the levels of bone biochemical markers and cytokines were detected with ELISA kits. Results. Gujiansan administration ameliorated SANFH and induced the expression of hypoxia-inducible factor-1α (HIF-1α), Bcl-2/adenovirus E1B 19 kDa interacting protein 3 (BNIP3), LC3, and Beclin-1 in the rat model in a dose- and time-dependent manner, and Gujiansan promoted osteocalcin secretion at the femoral head. In addition, Gujiansan increased the levels of bone formation- and bone resorption-specific markers (osteocalcin (OC), bone-specific alkaline phosphatase (BAP), tartrate resistant acid phosphatase-5b (TRACP-5b), N-terminal telopeptides of type I collagen (NTX-1), and C-terminal telopeptide of type I collagen (CTX-1)) and decreased the levels of proinflammatory cytokines (TNF-α, IL-6, and CRP) in a dose- and time-dependent manner. Conclusions. Gujiansan accelerates the formation of a new bone, promotes the absorption of the damaged bone, inhibits the inflammatory response, induces autophagy of the femoral head via the HIF-1α/BNIP3 pathway, and ultimately ameliorates SANFH.

scholarly journals SAT0298 IS INTERLEUKIN 6 A FACTOR OF FIBROGENESIS IN DERMAL FIBROBLASTS?

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 1094.1-1094
Author(s):  
A. S. Siebuhr ◽  
P. Juhl ◽  
M. Karsdal ◽  
A. C. Bay-Jensen
Keyword(s):  
Gene Expression ◽  
Type I Collagen ◽  
Collagen Type ◽  
Collagen Type I ◽  
Dermal Fibroblasts ◽  
Type I ◽  
Dependent Manner ◽  
Full Time ◽  
Collagen Formation ◽  
Type Iii

Background:Interleukin 6 (IL-6) is known to have both pro- and anti-inflammatory properties, depending on the receptor activation. The classical IL-6 signaling via the membrane bound receptor is mainly anti-inflammatory, whereas signaling through the soluble receptor (sIL-6R) is pro-inflammatory/pro-fibrotic. However, the direct fibrotic effect of IL-6 stimulation on dermal fibroblasts is unknown.Objectives:We investigated the fibrotic effect of IL-6 + sIL-6R in a dermal fibroblast model and assessed fibrosis by neo-epitope biomarkers of extracellular matrix proteins.Methods:Primary healthy human dermal fibroblasts were grown for up to 17 days in DMEM medium with 0.4% fetal calf serum, ficoll (to produce a crowded environment) and ascorbic acid. IL-6 [1-90 nM]+sIL-6R [0.1-9 nM] alone or in combination with TGFβ [1 nM] were tested in three different donors. TGFβ [1 nM], PDGF-AB [3 nM] and non-stimulated cells (w/o) were used as controls. Tocilizumab (TCZ) with TGFβ + IL-6 + sIL-6R stimulation was tested in one donor. Collagen type I, III and VI formation (PRO-C1, PRO-C3 and PRO-C6) and fibronectin (FBN-C) were evaluated by validated ELISAs (Nordic Bioscience). Western blot analysis investigated signal cascades. Gene expression of selected ECM proteins was analyzed. Statistical analyses included One-way and 2-way ANOVA and area under the curve analysis.Results:formation by the end of the culture period. The fibronectin and collagen type VI signal were consistent between the three tested donors, whereas the formation of type III collagen was only increased in one donor, but in several trials. Type I collagen formation was unchanged by IL-6 + sIL-6R stimulation. The gene expression of type I collagen was induced by IL-6 + sIL-6R. Western blot analysis validated trans-signaling by the IL-6+sIL-6R stimulation as expected.IL-6 + sIL-6R stimulation in combination with TGFβ decreased fibronectin levels compared to TGFβ alone but did not reach the level of unstimulated fibroblasts. The formation of collagen type IV was generally unchanged with IL-6 + sIL-6R + TGFβ compared to TGFβ alone. Collagen type I and III formation was more scattered in the signals when IL-6 + sIL-6R was in combination with TGFβ, as the biomarker level could be either decreased or increased compared to TGFβ alone. In two studies the type I collagen level was synergistic increased by IL-6 + sIL-6R + TGFβ, whereas another study found the level to be decreased compared to TGFβ alone. The gene expression of fibronectin and type I collagen was increased with TGFβ +IL-6+sIL-6R compared to TGFβ alone.Inhibition of IL-6R by TCZ in combination with IL-6 + sIL-6R did only decrease the fibronectin level with the lowest TCZ concentration (p=0.03). TCZ alone decreased the fibronectin level in a dose-dependent manner (One-way ANOVA p=0.0002).Conclusion:We investigated the fibrotic response of dermal fibroblasts to IL-6 + sIL-6R stimulation. IL-6 modulated the fibronectin level and modulated the collagen type III formation level in a somewhat dose-dependent manner. In combination with TGFβ, IL-6 decreased collagen type I and IV formation and fibronectin. However, in this study inhibition of IL-6R by TCZ did not change the fibrotic response of the dermal fibroblasts. This study indicated that IL-6 did not induce collagen formation in dermal fibroblasts, except type III collagen formation with high IL-6 concentration.Figure:Disclosure of Interests:Anne Sofie Siebuhr Employee of: Nordic Bioscience, Pernille Juhl Employee of: Nordic Bioscience, Morten Karsdal Shareholder of: Nordic Bioscience A/S., Employee of: Full time employee at Nordic Bioscience A/S., Anne-Christine Bay-Jensen Shareholder of: Nordic Bioscience A/S, Employee of: Full time employee at Nordic Bioscience A/S.

scholarly journals Differential bioactivity of four BMP-family members as function of biomaterial stiffness

2021 ◽  
Author(s):  
Adrià Sales ◽  
Valia Khodr ◽  
Paul Machillot ◽  
Laure Fourel ◽  
Amaris Guevara-Garcia ◽  
...  
Keyword(s):  
Cellular Response ◽  
Cell Spreading ◽  
Cell Number ◽  
Type I ◽  
Dependent Manner ◽  
Bone Differentiation ◽  
Bmp Receptors ◽  
Smad Phosphorylation ◽  
Matrix Bound ◽  
Automated Screening

ABSTRACTWhereas soft biomaterial is not able to induce cell spreading, BMP-2 presented by a soft film has been described to be sufficient to trigger cell spreading, migration and downstream BMP-2 signaling. Based on thin polyelectrolyte films of controlled stiffness, we investigated whether the presentation of four BMP members (2, 4, 7, 9) in a matrix-bound manner may differentially impact cell adhesion and bone differentiation of skeletal progenitors. We performed high content and automated screening of cellular responses, including cell number, cell spreading area, SMAD phosphorylation and alkaline phosphatase activity. The basolateral presentation of the different BMPs allowed us to discriminate the specificity of cellular response and the role of BMP receptors type I, type II, as well as three β integrins, in a BMP type and stiffness-dependent manner.

scholarly journals Role of cyclic nucleotides in rapid platelet adhesion to collagen

Blood ◽  
1994 ◽  
Vol 83 (9) ◽  
pp. 2508-2515 ◽  
Author(s):  
R Polanowska-Grabowska ◽  
AR Gear
Keyword(s):  
Cyclic Nucleotides ◽  
Platelet Adhesion ◽  
Type I Collagen ◽  
Arterial Flow ◽  
Type I ◽  
Dependent Manner ◽  
Flow Conditions ◽  
Nucleotide Synthesis ◽  
Cyclic Monophosphate ◽  
Beta 1 Integrin

Abstract Adhesion of human platelets to type I collagen under arterial flow conditions is extremely fast, being mediated primarily by the alpha 2 beta 1 integrin (glycoprotein Ia/IIa). We have investigated the involvement of cyclic nucleotides in platelet adhesion to soluble native collagen immobilized on Sepharose beads using a new microadhesion assay under arterial flow conditions. To prevent platelet stimulation by thromboxanes and adenosine diphosphate (ADP), experiments were performed with aspirin-treated platelets in the presence of ADP-removing enzyme systems such as creatine phosphate/creatine phosphokinase or apyrase. Rapid reciprocal changes in platelet adenosine 3′5′-cyclic monophosphate (cAMP) and guanosine 3′5′-cyclic monophosphate (cGMP) occurred during adhesion. cAMP levels in adherent platelets were 2.4-fold lower than in effluent platelets or in static controls, whereas cGMP levels were increased 2.4-fold. These results suggest that contact between platelets and collagen stimulates guanylate cyclase and inhibits adenylate cyclase. This occurs in the absence of the platelet release reaction. We also studied short-term effects of agents that regulate cyclic nucleotide synthesis, prostaglandin E1 (PGE1) and sodium nitroprusside (SNP). After only 3.8 seconds at 10 to 30 dyne/cm2, PGE1 (10 mumol/L) increased cAMP 16.4- fold, whereas SNP (50 mumol/L) increased cGMP ninefold and caused a 3.2- fold increase in cAMP. Both PGE1 and SNP rapidly (< 5 seconds) inhibited platelet adhesion in a dose-dependent manner that was correlated with the increase in cyclic nucleotides. Our data suggest that cAMP and cGMP play a regulatory role in the initial phases of platelet adhesion to collagen mediated by the alpha 2 beta 1 integrin receptor.

scholarly journals A study of the interaction in vitro between type I collagen and a small dermatan sulphate proteoglycan

1988 ◽  
Vol 251 (3) ◽  
pp. 643-648 ◽  
Author(s):  
N Uldbjerg ◽  
C C Danielsen
Keyword(s):  
Steady State ◽  
Binding Sites ◽  
Type I Collagen ◽  
Enzyme Linked Immunosorbent Assay ◽  
Side Chains ◽  
Type I ◽  
Dermatan Sulphate ◽  
Collagen Fibrillogenesis ◽  
High Affinity ◽  
Sulphate Proteoglycan

The interaction between a small dermatan sulphate proteoglycan isolated from human uterine cervix and collagen type I from human and rat skin was investigated by collagen-fibrillogenesis experiments. Collagen fibrillogenesis was initiated by elevation of temperature and pH after addition of proteoglycan, chondroitinase-digested proteoglycan or isolated side chains, and monitored by turbidimetry. Collagen-associated and unbound proteoglycan was determined by enzyme-linked immunosorbent assay after aggregation was complete. (1) The binding of proteoglycan to collagen could be explained by the presence of two mutually non-interacting binding sites, with Ka1 = 1.3 x 10(8) M-1 and Ka2 = 1.3 x 10(6) M-1. The number of binding sites per tropocollagen molecule was n1 = 0.11 and n2 = 1.1. The 0.1 high-affinity binding site per tropocollagen molecule indicates that the strong interaction between proteoglycan and collagen results from a concerted action of tropocollagen molecules in fibrils. Digestion of the proteoglycan with chondroitinase ABC did not affect these binding characteristics. (2) Proteoglycan did not affect the rate of fibrillogenesis, but increased the steady-state A400 by up to 90%. This increase was directly proportional to the saturation of the high-affinity type of binding sites. Neither isolated core protein nor isolated side chains induced a similar high increase in steady-state A400. (3) Electron micrographs showed that the fibril diameter was affected only to a minor extent, if at all, by the proteoglycan, whereas bundles of laterally aligned fibrils were common in the presence of proteoglycan. (4) Results obtained with human and rat collagen were similar.

scholarly journals Salivary Melatonin and the Severity of Attachment Loss: A Case-Control Study

2014 ◽  
Vol 2014 ◽  
pp. 1-4
Author(s):  
Leila Golpasand-Hagh ◽  
Faramarz Zakavi ◽  
Arash Daraeighadikolaei ◽  
Akram Ahangarpour ◽  
Sara Hajati ◽  
...  
Keyword(s):  
Chronic Periodontitis ◽  
Healthy Subjects ◽  
Type I Collagen ◽  
Periodontal Diseases ◽  
Protective Role ◽  
Enzyme Linked Immunosorbent Assay ◽  
Blood Levels ◽  
Melatonin Level ◽  
Type I ◽  
Salivary Melatonin

Background. Melatonin (MT: N-acetyl-5-methoxytryptamine) is a neuroendocrine hormone secreted mainly by the pineal gland in the brain. MT is produced with a circadian rhythm characterized by elevated blood levels during the night. In healthy individuals, maximal secretion of MT occurs between midnight and 2:00 am, whereas the minimal production occurs during the day. MT can be determined by repeated measurement of plasma or salivary MT or urine sulfatoxy-melatonin. Melatonin has powerful antioxidant effects, has an immunomodulatory role, stimulates the synthesis of type I collagen fibers, and promotes bone formation. Melatonin is also secreted in the saliva, although its role in the mouth is not known well. The purpose of this study was to examine the correlation between salivary melatonin level and periodontal diseases. Methods. Fifty subjects by mean age of 40.44±6.38 years were equally divided into 5 groups: 10 healthy subjects, 10 subjects with gingivitis, 10 subjects with localized moderate chronic periodontitis, 10 subjects with generalized moderate chronic periodontitis, and 10 subjects with generalized severe chronic periodontitis. Saliva samples were collected from all the subjects and melatonin levels were determined using an enzyme-linked immunosorbent assay. Two-way and one-way ANOVA and Tukey test were used to analyze relationships among variables. Results. Healthy subjects had significantly higher salivary melatonin level (5.29±0.50 pg/mL) compared to patients with gingivitis (4.35±0.30 pg/mL) (P<0.001). The difference between salivary melatonin level in patients with gingivitis and periodontitis was significant (P<0.001). Level of melatonin in patients with generalized severe chronic periodontitis (3.39±0.10 pg/mL) was significantly lower than that in other groups (P<0.01). Conclusions. This study determined that salivary melatonin level in patients with periodontal diseases is lower than that in healthy subjects. Consequently we conclude that there is a negative correlation between melatonin level and the severity of disease, suggesting that melatonin might have a protective role against periodontal diseases, although further research is required to validate this hypothesis.

scholarly journals Expression of Cytokine and Chemokine Genes by Human Middle Ear Epithelial Cells Induced by Influenza A Virus and Streptococcus pneumoniae Opacity Variants

2003 ◽  
Vol 71 (8) ◽  
pp. 4289-4296 ◽  
Author(s):  
H. H. Tong ◽  
J. P. Long ◽  
P. A. Shannon ◽  
T. F. DeMaria
Keyword(s):  
Streptococcus Pneumoniae ◽  
Mrna Expression ◽  
Influenza A Virus ◽  
Middle Ear ◽  
Influenza A ◽  
Primary Cultures ◽  
Enzyme Linked Immunosorbent Assay ◽  
Dependent Manner ◽  
Tnf Α ◽  
Human Middle Ear

ABSTRACT Real-time PCR and enzyme-linked immunosorbent assay were used to evaluate the ability of influenza A virus and Streptococcus pneumoniae opacity variants, either alone or in combination, to induce cytokine and chemokine genes in primary cultures of human middle ear epithelial (HMEE) cells. Following treatment with influenza A virus, the induction of gene expression, which occurred in a dose- and time-dependent manner, was strong for macrophage inflammatory protein 1α (MIP-1α) and MIP-1β; moderate for tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), and IL-8; and weak for IL-1β and monocyte chemotactic peptide 1 (MCP-1). Except for TNF-α, all the gene products were detected in the cell culture supernatants. In contrast, infection of HMEE cells with S. pneumoniae alone induced low levels of mRNA expression of MIP-1α and MIP-1β and did not significantly induce the transcription of the other cytokines and chemokines examined. However, both S. pneumoniae opacity variants increased mRNA expression of MIP-1α, MIP-1β, IL-6, and MCP-1 in HMEE cells activated by a prior influenza A virus infection compared to levels in cells treated with either agent alone. Up-regulation of IL-6, IL-8, and MCP-1 mRNA expression and production by the virus in combination with opaque S. pneumoniae was two- to threefold higher than that induced by the virus combined with the transparent S. pneumoniae variant. These data indicate that the activation of HMEE cells by influenza A virus enhances the induction of cytokine and chemokine gene transcripts by S. pneumoniae and that this effect appears to be most pronounced when S. pneumoniae is in the opaque phase.

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