Rapid up-regulation of alpha4 integrin-mediated leukocyte adhesion by transforming growth factor-beta1

Salivary Biomarkers for Diagnosis of Inflammatory Bowel Diseases: A Systematic Review

Saliva as a biological fluid has a remarkable potential in the non-invasive diagnostics of several systemic disorders. Inflammatory bowel diseases are chronic inflammatory disorders of the gastrointestinal tract. This systematic review was designed to answer the question “Are salivary biomarkers reliable for the diagnosis of inflammatory bowel diseases?”. Following the inclusion and exclusion criteria, eleven studies were included (according to PRISMA statement guidelines). Due to their heterogeneity, the potential salivary markers for IBD were divided into four groups: oxidative status markers, inflammatory cytokines, microRNAs and other biomarkers. Active CD patients manifest decreased activity of antioxidants (e.g., glutathione, catalase) and increased lipid peroxidation. Therefore, malondialdehyde seems to be a good diagnostic marker of CD. Moreover, elevated concentrations of proinflammatory cytokines (such as interleukin 1β, interleukin 6 or tumour necrosis factor α) are associated with the activity of IBD. Additionaly, selected miRNAs are altered in saliva (overexpressed miR-101 in CD; overexpressed miR-21, miR-31, miR-142-3p and underexpressed miR-142-5p in UC). Among other salivary biomarkers, exosomal PSMA7, α-amylase and calprotectin are detected. In conclusion, saliva contains several biomarkers which can be used credibly for the early diagnosis and regular monitoring of IBD. However, further investigations are necessary to validate these findings, as well as to identify new reliable salivary biomarkers.

GDF-15 inhibits integrin activation and mouse neutrophil recruitment through the ALK-5/TGF-βRII heterodimer

A classical TGF-β receptor pair counteracts extravasation of myeloid cells by rapidly interfering with integrin activation. GDF-15 and TGF-β1 inhibit leukocyte integrin activation by targeting the Rap-1 GTPase exchange factor CalDAG-GEF1.

VCAM-1 is a TGF-β1 inducible gene upregulated in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic lethal interstitial lung disease of unknown etiology. We previously reported that high plasma levels of vascular cell adhesion molecule 1 (VCAM-1) predict mortality in IPF subjects. Here we investigated the cellular origin and potential role of VCAM-1 in regulating primary lung fibroblast behavior. VCAM-1 mRNA was significantly increased in lungs of subjects with IPF compared to lungs from control subjects (p=0.001), and it negatively correlated with two markers of lung function, forced vital capacity (FVC) and pulmonary diffusion capacity for carbon monoxide (DLCO). VCAM-1 protein levels were highly expressed in IPF subjects where it was detected in fibrotic foci and blood vessels of IPF lung. Treatment of human lung fibroblasts with TGF-β1 significantly increased steady-state VCAM1 mRNA and protein levels without affecting VCAM1 mRNA stability. Further, cellular depletion of VCAM-1 inhibited fibroblast cell proliferation and reduced G2/M and S phases of the cell cycle suggestive of cell cycle arrest. These effects on cell cycle progression triggered by VCAM1 depletion were associated with reductions in levels of phosphorylated extracellular regulated kinase 1/2 and cyclin D1. Thus, these observations suggest that VCAM-1 is a TGF-β1 responsive mediator that partakes in fibroblast proliferation in subjects with IPF.

The role of laquinimod in modulation of the immune response in relapsing-remitting multiple sclerosis: Lessons from gene expression signatures

Laquinimod, is a potential oral immunomodulatory drug, for relapsing-remitting multiple sclerosis (RRMS). We analyzed the blood-transcriptional changes in RRMS patients (who participated in the ALLEGRO clinical trial) at one and six months after laquinimod treatment using gene expression microarrays. The molecular effects of laquinimod were enhanced by duration of treatment and showed down-regulation of inflammatory responses mainly via TGFb signaling, and of pro-inflammatory cytokines as well as of cellular movement, including adhesion, migration and leukocyte extravasation signaling. Our results demonstrate that laquinimod suppresses inflammation through down-regulation of inflammatory cytokines and arrest of leukocyte extravasation and thereby could attenuate disease activity in RRMS patients.

Predictive markers of clinical outcome in the GRMD dog model of Duchenne muscular dystrophy

In the translational process of developing innovative therapies for DMD (Duchenne muscular dystrophy), the last preclinical validation step is often carried out in the most relevant animal model of this human disease, namely the GRMD (Golden Retriever muscular dystrophy) dog. The disease in GRMD dogs mimics human DMD in many aspects, including the inter-individual heterogeneity. This last point can be seen as a drawback for an animal model but is inherently related to the disease in GRMD dogs closely resembling that of individuals with DMD. In order to improve the management of this inter-individual heterogeneity, we have screened a combination of biomarkers in sixty-one 2-month-old GRMD dogs at the onset of the disease and a posteriori we addressed their predictive value on the severity of the disease. Three non-invasive biomarkers obtained at early stages of the disease were found to be highly predictive for the loss of ambulation before 6 months of age. An elevation in the number of circulating CD4⁺CD49d^hi T cells and a decreased stride frequency resulting in a reduced spontaneous speed were found to be strongly associated with the severe clinical form of the disease. These factors can be used as predictive tests to screen dogs to separate them into groups with slow or fast disease progression before their inclusion into a therapeutic preclinical trial, and therefore improve the reliability and translational value of the trials carried out on this invaluable large animal model. These same biomarkers have also been described to be predictive for the time to loss of ambulation in boys with DMD, strengthening the relevance of GRMD dogs as preclinical models of this devastating muscle disease.

PDE8 regulates rapid Teff cell adhesion and proliferation independent of ICER

BACKGROUND

Abolishing the inhibitory signal of intracellular cAMP by phosphodiesterases (PDEs) is a prerequisite for effector T (Teff) cell function. While PDE4 plays a prominent role, its control of cAMP levels in Teff cells is not exclusive. T cell activation has been shown to induce PDE8, a PDE isoform with 40- to 100-fold greater affinity for cAMP than PDE4. Thus, we postulated that PDE8 is an important regulator of Teff cell functions.

METHODOLOGY/PRINCIPAL FINDINGS

We found that Teff cells express PDE8 in vivo. Inhibition of PDE8 by the PDE inhibitor dipyridamole (DP) activates cAMP signaling and suppresses two major integrins involved in Teff cell adhesion. Accordingly, DP as well as the novel PDE8-selective inhibitor PF-4957325-00 suppress firm attachment of Teff cells to endothelial cells. Analysis of downstream signaling shows that DP suppresses proliferation and cytokine expression of Teff cells from Crem-/- mice lacking the inducible cAMP early repressor (ICER). Importantly, endothelial cells also express PDE8. DP treatment decreases vascular adhesion molecule and chemokine expression, while upregulating the tight junction molecule claudin-5. In vivo, DP reduces CXCL12 gene expression as determined by in situ probing of the mouse microvasculature by cell-selective laser-capture microdissection.

CONCLUSION/SIGNIFICANCE

Collectively, our data identify PDE8 as a novel target for suppression of Teff cell functions, including adhesion to endothelial cells.

alpha3beta1 integrin-controlled Smad7 regulates reepithelialization during wound healing in mice

Effective reepithelialization after injury is essential for correct wound healing. The upregulation of keratinocyte alpha3beta1 integrin during reepithelialization suggests that this adhesion molecule is involved in wound healing; however, its precise role in this process is unknown. We have shown here that retarded reepithelialization in Itga3(-/-) mouse skin wounds is due predominantly to repressed TGF-beta1-mediated responses. Specifically, expression of the inhibitor of TGF-beta1-signaling Smad7 was elevated in Itga3(-/-) keratinocytes. Indeed, in vivo blockade of Smad7 increased the rate of reepithelialization in Itga3(-/-) and WT wounds to similar levels. Our data therefore indicate that the function of alpha3beta1 integrin as a mediator of keratinocyte migration is not essential for reepithelialization but suggest instead that alpha3beta1 integrin has a major new in vivo role as an inhibitor of Smad7 during wound healing. Moreover, our study may identify a previously undocumented function for Smad7 as a regulator of reepithelialization in vivo and implicates Smad7 as a potential novel target for the treatment of cutaneous wounds.

Pleomorphic adenoma and adenoid cystic carcinoma: in vitro study of the impact of TGFbeta1 on the expression of integrins and cytoskeleton markers of cell differentiation

Pleomorphic adenoma (PA) and adenoid cystic carcinoma (ACC) are the commonest benign and malignant salivary gland tumours respectively. Interactions between cells and extracellular matrix of PA and ACC, partially mediated by integrins, are important in their biology. The expression of integrins is regulated by numerous factors, amongst them, transforming growth factor beta1 (TGFbeta1). Our study investigated the effects of TGFbeta1 on the expression of integrin beta subunits in vitro and on the expression of cytoskeletal proteins of cells derived from PA and ACC. The expression of cytoskeletal differentiation markers and integrins was assessed using immunofluorescence. ELISA assays were employed to quantitate the expression integrins and MTT assays evaluated the mitochondrial activity of cells stimulated with TGFbeta1. PA cells showed increased expression of integrins and de novo expression of differentiation markers upon TGFbeta1 stimulation. ACC cells were less responsive to such stimulation. This may reflect important differences in the biological behaviour of benign and malignant cells.

Association and interaction of the TNF-alpha gene with other pro- and anti-inflammatory cytokine genes and HLA genes in patients with type 1 diabetes from North India

Type 1 diabetes (T1D) is a multifactorial autoimmune disorder where major histocompatibility complex (MHC) genes and the insulin-linked polymorphic region have been shown to play major roles. We report here an integrated effect of tumor necrosis factor (TNF) alpha with other cytokine genes. The TNF-alpha-308 GA and AA (high secretor) polymorphisms were significantly increased in the patients with T1D (n = 235) [P < 7 x 10(-6), odds ratio (OR) = 3.04, 95% confidence interval (CI) = 1.8-5.3] compared with the controls (n= 128). The variants of interferon-gamma (IFN-gamma) (A(+874)T), interleukin (IL)-6 (G(-174)C), IL-10 (A(-1082)G, T(-819)C, C(-592)A) and transforming growth factor (TGF) beta1 (T(cdn10)C, G(cdn25)C) did not show a significant difference between patients and controls. However, simultaneous presence of TNF-alpha-308 GA+AA along with both high and low secretor genotypes of IFN-gamma (P < 0.003) was significantly increased in patients. Simultaneous presence of TNF-alpha-308 GA + AA along with high secretor genotypes of IL-6 (P < 0.0001, OR = 2.61, 95% CI = 1.5-4.56), IL-10 (P < 0.0001, OR = 4.26, 95% CI = 1.9-10.1) and TGF-beta1 (P < 0.00004, OR = 2.8, 95% CI = 1.6-4.86) was also significantly increased in patients with T1D. Low secretor genotype of TNF-alpha-308 GG along with low secretor genotypes of IFN-gamma (P < 0.001, OR = 0.465, 95% CI = 0.28-0.77), high secretor genotypes of IL-6 (P < 0.000004, OR = 0.76, 95% CI = 0.227-0.621) and TGF-beta1 (P < 0.000006, OR = 0.336, 95% CI = 0.198-0.568) was protective. The TNF-alpha-308 G allele was in linkage disequilibrium (LD) with the human leukocyte antigen (HLA)-B*0801-DRB1*0301 haplotype, while TNF-alpha-308 A allele was in LD with the HLA-B*5001-DRB1*0301 and B*5801-DRB1*0301 haplotypes, suggesting that the effect of TNF-alpha -308 A allele is not because of its being in LD with any HLA alleles, but because of its functional role and its integrated effect with other cytokines.

Intracellular signaling required for CCL25-stimulated T cell adhesion mediated by the integrin alpha4beta1

The alpha4beta1 integrin is expressed on thymocytes and mediates cell attachment to its ligands CS-1/fibronectin (CS-1/FN) and VCAM-1 in the thymus. The chemokine CCL25 is highly expressed in the thymus, where it binds to its receptor CCR9 on thymocytes promoting migration and activation. We show here that alpha4beta1 and CCR9 are coexpressed mainly on double- and single-positive thymocytes and that CCL25 strongly stimulates CD4(+)CD8(+) and CD4(+)CD8(-) adhesion to CS-1/FN and VCAM-1. CCL25 rapidly activated the GTPases Rac and Rap1 on thymocytes, and this activation was required for stimulation of adhesion, as detected using the CCR9(+)/alpha4beta1(+) human T cell line Molt-4. To study the role on CCL25-stimulated adhesion of the Rac downstream effector Wiskott-Aldrich syndrome protein family verproline-homologous protein 2 (WAVE2) as well as of Rap1-GTP-interacting proteins, regulator of adhesion and cell polarization enriched in lymphoid tissues (RAPL) and Rap1-GTP-interacting adapter molecule (RIAM), we knocked down their expression and tested transfectant attachment to alpha4beta1 ligands. We found that WAVE2 and RAPL but not RIAM were required for efficient triggering by CCL25 of T cell adhesion to CS-1/FN and VCAM-1. Although Rac and Rap1 activation was required during early steps of T cell adhesion stimulated by CCL25, WAVE2 was needed for the development of actin-dependent T cell spreading subsequent to adhesion strengthening but not during initial alpha4beta1-ligand interactions. These results suggest that regulation by CCL25 of adhesion of thymocyte subpopulations mediated by alpha4beta1 could contribute to control their trafficking in the thymus during maturation, and identify Rac-WAVE2 and Rap1-RAPL as pathways whose activation is required in inside-out signaling, leading to stimulated adhesion.

Study on the Correlations among Disease Activity Index and Salivary Transforming Growth Factor-beta1 and Nitric Oxide in Ulcerative Colitis Patients

Growth factors and nitric oxide (NO) play a major role in dysregulated immune response in ulcerative colitis (UC). Recent evidence has shown increased levels of transforming growth factor-beta(1) (TGF-beta(1)) in UC and suggested an anti-inflammatory effect for this factor. Based on our recent study, dysfunctional immunoregulation is present in saliva of UC patients, we hypothesized that salivary level of NO and TGF-beta(1) may differ by severity of UC and be useful to determine the activity of the disease. Thirty-seven UC patients and 15 healthy controls were enrolled and saliva samples were obtained. Truelove-Witts severity index and modified Truelove-Witts severity index were used to determine the severity of the disease. NO and TGF-beta(1) levels were detected in saliva of all patients and control subjects using enzyme-linked immunosorbent assay. A total of 21 patients had mild disease while 8 had moderate and 8 had severe colitis. Adjusted for baseline characteristics, the levels of NO and TGF-beta(1) in different groups were compared. Salivary NO and TGF-beta(1) levels were higher in UC patients comparing to controls (P < 0.00005 and P = 0.005, respectively). The levels of NO and TGF-beta(1) showed no significant differences among the severity groups (P = 0.46 and P = 0.23, respectively). NO levels linearly increased by age (Coeff = 1.5, r = 0.38, P = 0.02). Gender, extension of disease, and medical treatment did not affect NO and TGF-beta(1) levels. Although UC patients have abnormal amounts of NO and TGF-beta(1) in their saliva, their disease activity cannot be predicted by these factors, which may indicate a pathophysiologic role rather than being nonspecific inflammatory markers for TGF-beta(1) and NO.

Alterations in Salivary Antioxidants, Nitric Oxide, and Transforming Growth Factor-β1in Relation to Disease Activity in Crohn's Disease Patients

It has been postulated that oxidative stress, nitric oxide (NO), and transforming growth factor beta(1) (TGF- beta(1)) have major roles in the pathophysiology of Crohn's disease (CD). The aim of this study was to determine the salivary levels of total antioxidant capacity (TAC), specific antioxidants (i.e., uric acid, albumin, transferrin, and thiol molecules), lipid peroxidation (LPO), NO, and TGF- beta(1) in CD patients and control subjects and to also investigate their correlation with activity of the disease. Twenty-eight patients with confirmed diagnosis of CD were enrolled and whole saliva samples were obtained. Smokers, diabetics, those who suffered from periodontitis, and those who were consuming antioxidant supplements were excluded from the study. The Crohn's Disease Activity Index (CDAI) was used to determine the severity of the disease. Twenty healthy subjects were also recruited. In CD patients significant reductions in salivary levels of TAC (0.248 +/- 0.145 vs. 0.342 +/- 0.110 mmol/L), albumin (1.79 +/- 0.42 vs. 2.3 +/- 0.2 microg/mL), and uric acid (3.1 +/- 1.4 vs. 4.1 +/- 2.0 mg/dL) were found. TGF-beta(1) was significantly increased in CD patients compared to healthy subjects (3.02 +/- 1.54 vs. 2.36 +/- 0.52 ng/mL). A fourfold increase in NO levels (198.8 +/- 39.9 vs. 50.2 +/- 21.3 micromol/L) along with a fivefold increase in LPO concentration (0.146 +/- 0.064 vs. 0.027 +/- 0.019 micromol/L) was documented in CD patients in comparison to the control group. CDAI significantly correlated with the TAC, LPO, and the interaction between TAC and LPO (r(2) = 0.625, r(2) = 0.8, F-test's P < 0.00005). Saliva of CD patients exhibits an abnormal feature with respect to oxidative stress, NO, and TGF-beta(1). TAC and LPO modify the effect of each other in determination of CD severity, which underlines the importance of oxidative stress in the pathogenesis of CD.

DOCK2 is Required for Chemokine-Promoted Human T Lymphocyte Adhesion Under Shear Stress Mediated by the Integrin α4β1

The alpha4beta1 integrin is an essential adhesion molecule for recruitment of circulating lymphocytes into lymphoid organs and peripheral sites of inflammation. Chemokines stimulate alpha4beta1 adhesive activity allowing lymphocyte arrest on endothelium and subsequent diapedesis. Activation of the GTPase Rac by the guanine-nucleotide exchange factor Vav1 promoted by CXCL12 controls T lymphocyte adhesion mediated by alpha4beta1. In this study, we investigated the role of DOCK2, a lymphocyte guanine-nucleotide exchange factor also involved in Rac activation, in CXCL12-stimulated human T lymphocyte adhesion mediated by alpha4beta1. Using T cells transfected with DOCK2 mutant forms defective in Rac activation or with DOCK2 small interfering RNA, we demonstrate that DOCK2 is needed for efficient chemokine-stimulated lymphocyte attachment to VCAM-1 under shear stress. Flow chamber, soluble binding, and cell spreading assays identified the strengthening of alpha4beta1-VCAM-1 interaction, involving high affinity alpha4beta1 conformations, as the adhesion step mainly controlled by DOCK2 activity. The comparison of DOCK2 and Vav1 involvement in CXCL12-promoted Rac activation and alpha4beta1-dependent human T cell adhesion indicated a more prominent role of Vav1 than DOCK2. These results suggest that DOCK2-mediated signaling regulates chemokine-stimulated human T lymphocyte alpha4beta1 adhesive activity, and that cooperation with Vav1 might be required to induce sufficient Rac activation for efficient adhesion. In contrast, flow chamber experiments using lymph node and spleen T cells from DOCK2(-/-) mice revealed no significant alterations in CXCL12-promoted adhesion mediated by alpha4beta1, indicating that DOCK2 activity is dispensable for triggering of this adhesion in mouse T cells, and suggesting that Rac activation plays minor roles in this process.

TGFbeta1-induced aortic endothelial morphogenesis requires signaling by small GTPases Rac1 and RhoA

TGFbeta is a potent regulator of cell differentiation in many cell types. On aortic endothelial cells, TGFbeta1 displays angiogenic properties in inducing capillary-like tube formation in collagen I gels, in vitro. We investigated cytoskeletal changes that precede tube formation and related these alterations to the effects of TGFbeta1 on the activation state of members of the RhoGTPase family. TGFbeta1 promotes cell elongation and stress fiber formation in aortic endothelial cells. Using cell lines with inducible expression of Rac1 mutants, we show that these events are mimicked by expression of dominant-negative Rac1 whereas the constitutively active mutant prevents the TGFbeta1-mediated change of phenotype. Although TGFbeta1 induces an initial rise in the Rac1-GTP content, this phase is followed by a prolonged loss of the active form. In contrast, RhoA activity increases progressively and reaches a plateau when Rac1-GTP is no longer detectable. Prolonged inhibition of Rac1 appears necessary and sufficient for the increase in RhoA-GTP. In situ examination of Rho activity in TGFbeta1-treated cells provides evidence that active RhoA relocalizes to the tips of elongated cells. Inhibiting the Rho effector ROCK abrogates tube formation. Thus, Rac1 and RhoA are regulated by TGFbeta1 in the process of endothelial tube formation in collagen I gels.

TGF-beta1-mediated activations of c-Src and Rac1 modulate levels of cyclins and p27(Kip1) CDK inhibitor in hepatoma cells replated on fibronectin

Integrin-mediated cell adhesion transduces signals to regulate actin cytoskeleton and cell proliferation. While understanding how integrin signals cross-talk with the TGF-beta1 pathways, we observed lamellipodia formation and cyclin regulation in Hep3B cells, following TGF-beta1 treatment. To answer if integrin signaling via actin organization might regulate cell cycle progression after TGF-beta1 treatment, we analyzed cross-talk between the two receptor-mediated pathways in hepatoma cells on specific ECMs. We found that basal and TGF-beta1-mediated activation of c-Src and Rac1, expression of cyclins E and A, and suppression of p27Kip1 were significant in cells replated on fibronectin, but not in cells on collagen I, indicating a different integrin-mediated cellular response to TGF-beta1 treatment. Levels of tyrosine phosphorylation and actin-enriched lamellipodia on fibronectin were also more prominent than in cells on collagen I. Studies using pharmacological inhibitors or transient transfections revealed that the preferential TGF-beta1 effects in cells on fibronectin required c-Src family kinase activity. These observations suggest that a specific cross-talk between TGF-beta1 and fibronectin-binding integrin signal pathways leads to the activation of c-Src/Rac1/actin-organization, leading to changes in cell cycle regulator levels in hepatoma cells. Therefore, this study represents another mechanism to regulate cell cycle regulators when integrin signaling is collaborative with TGF-beta1 pathways.

Vav1 and Rac control chemokine-promoted T lymphocyte adhesion mediated by the integrin alpha4beta1

The chemokine CXCL12 promotes T lymphocyte adhesion mediated by the integrin alpha4beta1. CXCL12 activates the GTPase Rac, as well as Vav1, a guanine-nucleotide exchange factor for Rac, concomitant with up-regulation of alpha4beta1-dependent adhesion. Inhibition of CXCL12-promoted Rac and Vav1 activation by transfection of dominant negative Rac or Vav1 forms, or by transfection of their siRNA, remarkably impaired the increase in T lymphocyte attachment to alpha4beta1 ligands in response to this chemokine. Importantly, inhibition of Vav1 expression by RNA interference resulted in a blockade of Rac activation in response to CXCL12. Adhesions in flow chambers and soluble binding assays using these transfectants indicated that initial ligand binding and adhesion strengthening mediated by alpha4beta1 were dependent on Vav1 and Rac activation by CXCL12. Finally, CXCL12-promoted T-cell transendothelial migration involving alpha4beta1-mediated adhesion was notably inhibited by expression of dominant negative Vav1 and Rac. These results indicate that activation of Vav1-Rac signaling pathway by CXCL12 represents an important inside-out event controlling efficient up-regulation of alpha4beta1-dependent T lymphocyte adhesion.

Transforming growth factor-{beta}1 modulates responses of CD34+ cord blood cells to stromal cell-derived factor-1/CXCL12

Disruption of stromal cell-derived factor-1 (SDF-1/CXCL12 [CXC chemokine ligand 12]) interaction leads to mobilization of stem/progenitor cells from bone marrow to circulation. However, prolonged exposure of CD34+ cells to SDF-1 desensitizes them to SDF-1. So how do cells remain responsive to SDF-1 in vivo when they are continuously exposed to SDF-1? We hypothesized that one or more mechanisms mediated by cytokines exist that could modulate SDF-1 responsiveness of CD34+ cells and the desensitization process. We considered transforming growth factor-beta1 (TGF-beta1) a possible candidate, since TGF-beta1 has effects on CD34+ cells and is produced by stromal cells, which provide niches for maintenance and proliferation of stem/progenitor cells. TGF-beta1 significantly restored SDF-1-induced chemotaxis and sustained adhesion responses in cord blood CD34+ cells preexposed to SDF-1. Effects of TGF-beta1 were dependent on the dose and duration of TGF-beta1 pretreatment. Phosphorylation of extracellular signal-regulated kinase 1 (Erk1)/Erk2 was implicated in TGF-beta1 modulation of migratory and adhesion responses to SDF-1. Our results indicate that low levels of TGF-beta1 can modulate SDF-1 responsiveness of CD34+ cells and thus may facilitate SDF-1-mediated retention and nurturing of stem/progenitor cells in bone marrow.

Protein microarray analysis of disease activity in pediatric inflammatory bowel disease demonstrates elevated serum PLGF, IL-7, TGF-beta1, and IL-12p40 levels in Crohn's disease and ulcerative colitis patients in remission versus active disease

OBJECTIVES

Cytokines and growth factors play a major role in the dysregulated immune response in inflammatory bowel disease (IBD). We hypothesized that significant differences exist between the serum cytokine and growth factor profiles of pediatric IBD patients with active disease (AD) and those in remission, and that levels of some of these soluble mediators may be used to define regulators in IBD and determine disease activity.

METHODS

Eighty-eight consecutive patients with confirmed Crohn's disease (CD) and ulcerative colitis (UC) seen at the Duke Children's Hospital were prospectively enrolled and a serum sample was obtained. Data were recorded at the time of serum collection to calculate disease activity indices. The relative expression of 78 cytokines, growth factors, and soluble receptors was determined using proprietary antibody-based protein microarrays amplified by rolling circle amplification. SPSS 8 (SPSS Inc., Chicago, IL) was used to compare protein profiles for CD and UC patients in clinical remission (CR) versus AD.

RESULTS

Sixty-five CD patients and 23 UC patients were enrolled. Forty-one CD patients had available samples and PCDAI results. Twenty-two patients were in remission PCDAI < or = 12.5 (median 5), 19 patients had disease activity >15 (median 30). Univariate analysis revealed that PLGF, IL-7, IL-12p40, and TGF-beta1 cytokine levels were significantly elevated for patients in CR versus AD (p < 0.01). Twelve UC serum samples had Seo/Truelove Witt AI for analysis. Five patients were in remission by TW AI and Seo AI < or =110 and 7 patients had active mild-to-severe disease by TW and Seo AI >110. Only one cytokine, IL12p40, showed significance between CR versus AD (p < 0.02).

CONCLUSIONS

Surprisingly, we found no differences in circulating levels of proinflammatory cytokines but found that pediatric IBD patients in remission compared to those with AD had higher levels of specific circulating cytokines, including the regulatory cytokines IL-12p40 and TGF-beta1. It may be that these cytokines directly regulate intestinal inflammation in IBD or reflect the activity of T regulatory cells in negatively regulating the inflammatory response. Further studies will be needed to validate our results to define the molecular pathways involved in the intestinal immune response in man.

Protein microarray analysis of disease activity in pediatric inflammatory bowel disease demonstrates elevated serum PLGF, IL-7, TGF-beta1, and IL-12p40 levels in Crohn's disease and ulcerative colitis patients in remission versus active disease

OBJECTIVES

Cytokines and growth factors play a major role in the dysregulated immune response in inflammatory bowel disease (IBD). We hypothesized that significant differences exist between the serum cytokine and growth factor profiles of pediatric IBD patients with active disease (AD) and those in remission, and that levels of some of these soluble mediators may be used to define regulators in IBD and determine disease activity.

METHODS

Eighty-eight consecutive patients with confirmed Crohn's disease (CD) and ulcerative colitis (UC) seen at the Duke Children's Hospital were prospectively enrolled and a serum sample was obtained. Data were recorded at the time of serum collection to calculate disease activity indices. The relative expression of 78 cytokines, growth factors, and soluble receptors was determined using proprietary antibody-based protein microarrays amplified by rolling circle amplification. SPSS 8 (SPSS Inc., Chicago, IL) was used to compare protein profiles for CD and UC patients in clinical remission (CR) versus AD.

RESULTS

Sixty-five CD patients and 23 UC patients were enrolled. Forty-one CD patients had available samples and PCDAI results. Twenty-two patients were in remission PCDAI < or = 12.5 (median 5), 19 patients had disease activity >15 (median 30). Univariate analysis revealed that PLGF, IL-7, IL-12p40, and TGF-beta1 cytokine levels were significantly elevated for patients in CR versus AD (p < 0.01). Twelve UC serum samples had Seo/Truelove Witt AI for analysis. Five patients were in remission by TW AI and Seo AI < or =110 and 7 patients had active mild-to-severe disease by TW and Seo AI >110. Only one cytokine, IL12p40, showed significance between CR versus AD (p < 0.02).

CONCLUSIONS

Surprisingly, we found no differences in circulating levels of proinflammatory cytokines but found that pediatric IBD patients in remission compared to those with AD had higher levels of specific circulating cytokines, including the regulatory cytokines IL-12p40 and TGF-beta1. It may be that these cytokines directly regulate intestinal inflammation in IBD or reflect the activity of T regulatory cells in negatively regulating the inflammatory response. Further studies will be needed to validate our results to define the molecular pathways involved in the intestinal immune response in man.

TGF-beta1 enhances betaig-h3-mediated keratinocyte cell migration through the alpha3beta1 integrin and PI3K

betaig-h3 is an extracellular matrix (ECM) protein whose expression is highly induced by transforming growth factor beta1 (TGF-beta1). We previously demonstrated that betaig-h3 has two alpha3beta1 integrin-interacting motifs, which promote adhesion, migration, and proliferation of human keratinocytes. Both betaig-h3 and TGF-beta1 have been suggested to play important roles in the healing of skin wounds. In this study, we demonstrate that TGF-beta1 enhances keratinocyte adhesion and migration toward betaig-h3 through the alpha3beta1 integrin. TGF-beta1 did not increase the amount of the alpha3beta1 integrin on the cell surface, but rather increased its affinity for betaig-h3. LY294002, an inhibitor of PI3K, blocked the basal and TGF-beta1-enhanced cell migration but not adhesion to betaig-h3. A constitutively active mutant of PI3K stimulated cell migration but not adhesion to betaig-h3. The PI3K pathway is also not associated with the affinity of the alpha3beta1 integrin to betaig-h3. TGF-beta1 induced phosphorylation of AKT and FAK. Taken together, these data suggest that TGF-beta1 increases affinity of the alpha3beta1 integrin to betaig-h3, resulting in enhanced adhesion and migration of keratinocytes toward betaig-h3. TGF-beta1 also enhances migration through PI3K, but PI3K is not associated with either the binding affinity of the alpha3beta1 integrin or its adhesion to betaig-h3.