Barrett’s Esophagus is considered to be a precursor to adenocarcinoma and the information on VDR expression in normal and Barrett’s esophagus is significantly lacking. In this study, we examined the expression of VDR in the lower esophagus and gastric cardia of normal and Barrett’s esophagus by immunofluorescence. Columnar mucosa but not squamous mucosa at the gastroesophageal junction showed positive immunofluorescence to VDR. Submucosal glands and ducts deep to the normal squamous mucosa stained positive for VDR and localized in the cytoplasm and perinuclear regions with no nuclear staining. Interestingly, the Barrett’s mucosa stained strongly positive for VDR. Glandular structures in the mucosal layer were far less abundant in the Barrett’s mucosa than in the normal gastric mucosa. As a result, fewer structures deep to the Barrett’s epithelial layer stained positive for VDR when compared to normal gastric mucosa. These findings suggest that in normal esophagus VDR expression is restricted to columnar epithelium and glandular structures. Furthermore, strong VDR expression in Barrett’s mucosa may indicate an increased sensitivity of this tissue to endogenous or therapeutic effects of Vitamin D.
Barrett’s esophagus; Epithelium; Gastroesophageal junction; Vitamin D; Vitamin D receptor
A potent immunomodulatory role of Vitamin D in both innate and adaptive immunity has recently been appreciated. In allergic asthma, activation of NF-κB induces transcription of various cytokines and chemokines involved in allergic airway inflammation. The nuclear import of activated NF-κB p50/RelA subunit is dependent on importin α3 (KPNA4) and importin α4 (KPNA3). In this study, we examined the role of importin α3 in immunomodulatory effect of calcitriol in human bronchial smooth muscle cells (HBSMCs).
Cultured HBSMCs were stimulated with calcitriol in the presence and absence of cytokines, TNF-α, IL-1β, and IL-10. The mRNA transcripts of importin α3 and α4 were analyzed using qPCR while protein expression of importin α3, α4 and nuclear RelA was analyzed by immunoblotting.
Calcitriol significantly decreased mRNA and protein expression of importin α3 as well as nuclear protein expression of NF-κB p65 (RelA). The decreased activation of RelA by calcitriol was confirmed by decreased release of RelA-inducible molecules, including IL-5, IL-6 and IL-8, by HBSMCs upon calcitriol treatment. Calcitriol attenuated the effect of TNF-α and IL-1β to upregulate mRNA and protein expression of importin α3. IL-10 significantly decreased the TNF-α induced expression of importin α3 and this effect was further potentiated by calcitriol.
These data suggest that under inflammatory conditions, calcitriol decreases the expression of importin α3 resulting in decreased nuclear import of activated RelA. This could be a novel mechanism by which calcitriol could exert its immunomodulatory effects to reduce allergic airway inflammation and thus may alleviate the symptoms in allergic asthma.
Active vitamin D; Allergic airway inflammation; Asthma; Bronchial smooth muscle cells; Calcitriol; Importinα3 (KPNA4); Importinα4 (KPNA3); NF-κB; Vitamin D receptor (VDR)
Esophageal adenocarcinoma carries a poor prognosis. Tumor response to neoadjuvant therapy is a key prognostic factor in patients with adenocarcinoma of the esophagus, but is inconsistent. Identifying tumor characteristics that portend a favorable response to neoadjuvant therapy would be a valuable clinical tool. The anticancer actions of vitamin D and its receptor may have implications. In this study, 15 biopsy specimens were procured retrospectively from patients being treated for adenocarcinoma of the esophagus. The tissue was immunostained for the vitamin D receptor and compared on the basis of response to neoadjuvant therapy. Tumors that did not respond to neoadjuvant therapy had greater expression of VDR than tumors that responded completely. Expression of VDR declined with tumor de-differentiation. The data suggest that a relationship between vitamin D receptor expression and response to neoadjuvant therapy is plausible.
Adenocarcinoma; Esophageal cancer; Neoadjuvant therapy; Vitamin D; Vitamin D receptor
Asthma is one of the most common chronic inflammatory diseases of the airways. Calcitriol exerts its action through Vitamin D receptor (VDR), which is a high affinity nuclear receptor. VDR is a transcription factor that alters the transcription of target genes which are involved in a wide spectrum of biological responses. Lower serum vitamin D levels are associated with airway hyperresponsiveness and increased asthma severity. Prohibitin is a ubiquitously expressed protein localized to the cell and mitochondrial membranes and the nucleus.
Methods and results
HBSMCs were cultured and treated with calcitriol and/or TNF-α. The mRNA and protein expression of prohibitin and VDR were analyzed using qPCR and immunoblotting, respectively. In the in vivo studies, female BALB/c mice were fed with special vitamin D-deficient or 2,000 IU/kg of vitamin D-supplemented diet for 13 weeks. Mouse model of allergic airway inflammation was developed by OVA-sensitization and challenge. The expression pattern of TNF-α, prohibitin and VDR in the lung of OVA-sensitized mice was analyzed using immunofluorescence. Calcitriol significantly increased and TNF-α decreased the protein and mRNA expression of prohibitin and VDR in HBSMCs. There was significantly increased expression of TNF-α and decreased expression of VDR and prohibitin in the lung of vitamin D-deficient mouse model of allergic airway inflammation.
These results suggest that under inflammatory conditions there is decreased expression of VDR resulting in decreased expression of prohibitin, which is a vitamin D target gene. Vitamin D deficiency causes increase in the expression of TNF-α, thereby increasing inflammation and decreases the expression of VDR and prohibitin. Supplementation with vitamin D reduces the levels of TNF-α, thereby increasing the expression of VDR and prohibitin that could be responsible for reducing allergic airway inflammation.
Allergic airway inflammation; Asthma; Human Bronchial Smooth Cells; Inflammation; Prohibitin; TNF-α; Vitamin D receptor; Vitamin D
Vitamin D is a sectosteroid that functions through Vitamin D receptor (VDR), a transcription factor, which controls the transcription of many targets genes. Vitamin D deficiency has been linked with cardiovascular diseases, including heart failure and coronary artery disease. Suppressor of cytokine signaling (SOCS)3 regulates different biological processes such as inflammation and cellular differentiation and is an endogenous negative regulator of cardiac hypertrophy.
The purpose of this study was to test the hypothesis that vitamin D deficiency causes cardiomyocyte hypertrophy and increased proinflammatory profile in epicardial adipose tissue(EAT), and this correlates with decreased expression of SOCS3 in cardiomyocytes and EAT.
Eight female Yucatan miniswine were fed vitamin D-sufficient (900 IU/d) or vitamin D-deficient hypercholesterolemic diet. Lipid profile, metabolic panel, and serum 25(OH)D levels were regularly measured. After 12 months animals were euthanized and histological, immunohistochemical and qPCR studies were performed on myocardium and epicardial fat.
Histological studies showed cardiac hypertrophy, as judged by cardiac myocyte cross sectional area, in vitamin D-deficient group. Immunohistochemical and qPCR analyses showed significantly decreased mRNA and protein expression of VDR and SOCS3 in cardiomyocytes of vitamin D-deficient animals. EAT from vitamin D-deficient group had significantly higher expression of TNF-α, IL-6, MCP-1, and decreased adiponectin in association with increased inflammatory cellular infiltrate. Interestingly, EAT from vitamin D-deficient group had significantly decreased expression of SOCS3.
These data suggest that vitamin D deficiency induces hypertrophy in cardiomyocytes which is associated with decreased expression of VDR and SOCS3. Vitamin D deficiency is also associated with increased inflammatory markers in EAT. Activity of VDR in the body is controlled through regulation of vitamin D metabolites. Therefore, restoration of VDR function by supplementation of VDR ligands in vitamin D- deficient population might be helpful in reducing inflammation and cardiovascular risk.
Cardiac Hypertrophy; Coronary Artery Disease; Epicardial Fat; Inflammation; Vitamin D
Gene therapy has attracted attention for its potential to treat several cardiovascular diseases. The use of adeno-associated viral (AAV) vectors to facilitate therapeutic gene transfer to suppress intimal hyperplasia is a promising concept. The objective of this study was to analyze the in vivo transduction of a novel recombinant AAV-2/9 vector with SM22α promoter, containing β-galactosidase gene (Lac Z) or green fluorescent protein (GFP) as reporter genes, to the medial layer smooth muscle cells (SMCs) of swine coronary and peripheral arteries.
The AAV2/9 vector containing SM22α (1×1013 pfu) were administered into carotid/femoral/coronary arteries of domestic swine using irrigating balloon catheter-based gene delivery. Following gene transfer, cryosections of arteries were processed for X-Gal and GFP analysis. Fluorescence microscopy and Western blotting were done to analyze the GFP expression in the SMCs.
LacZ mRNA expression was visualized in the medial layer 7 days after vector administration. The GFP expression was detected at 7th day and lasted for at least 2 months showing the longer-lasting expression of the AAV2/9-vector. Control arteries did not show any expression of GFP or LacZ. There was no significant effect of AAV2/9 viral transduction on serum amylase, fibrinogen and serum CRP levels.
These finding support the use of AAV2/9 as a vector to effectively transduce a gene in SMCs of coronary and peripheral arteries without causing inflammation.
Adeno-associated virus; Gene therapy; Intimal hyperplasia; Restenosis; Vascular smooth muscle cells; Vector
Migration to draining lymph nodes is a critical requirement for dendritic cells (DCs) to control T-cell–mediated immunity. The calcium-activated potassium channel KCa3.1 has been shown to be involved in regulating cell migration in multiple cell types. In this study, KCa3.1 expression and its functional role in lung DC migration were examined. Fluorescence-labeled antigen was intranasally delivered into mouse lungs to label lung Ag-carrying DCs. Lung CD11chighCD11blow and CD11clowCD11bhigh DCs from PBS-treated and ovalbumin (OVA)-sensitized mice were sorted using MACS and FACS. Indo-1 and DiBAC4(3) were used to measure intracellular Ca2+ and membrane potential, respectively. The mRNA expression of KCa3.1 was examined using real-time PCR. Expression of KCa3.1 protein and CCR7 was measured using flow cytometry. Migration of two lung DC subsets to lymphatic chemokines was examined using TransWell in the absence or presence of the KCa3.1 blocker TRAM-34. OVA sensitization up-regulated mRNA and protein expression of KCa3.1 in lung DCs, with a greater response by the CD11chighCD11blow than CD11clowCD11bhigh DCs. Although KCa3.1 expression in Ag-carrying DCs was higher than that in non–Ag-carrying DCs in OVA-sensitized mice, the difference was not as prominent. However, Ag-carrying lung DCs expressed significantly higher CCR7 than non–Ag-carrying DCs. CCL19, CCL21, and KCa3.1 activator 1-EBIO induced an increase in intracellular calcium in both DC subsets. In addition, 1-EBIO–induced calcium increase was suppressed by TRAM-34. In vitro blockade of KCa3.1 with TRAM-34 impaired CCL19/CCL21-induced transmigration. In conclusion, KCa3.1 expression in lung DCs is up-regulated by OVA sensitization in both lung DC subsets, and KCa3.1 is involved in lung DC migration to lymphatic chemokines.
allergic airway inflammation; antigen uptake; asthma; calcium-activated potassium channel; dendritic cell
Leukemia/lymphoma related factor/POK erythroid myeloid ontogenic factor (LRF/Pokemon) is a member of the POK family of proteins that promotes oncogenesis in several forms of cancer. Recently, we found higher LRF expression in human breast and prostate carcinomas compared to the corresponding normal tissues. The aim of this study was to examine the regulation of LRF expression in human prostate cells. Epidermal growth factor (EGF) and its receptors mediate several tumorigenic cascades that regulate cell differentiation, proliferation, migration and survival of prostate cancer cells. There was significantly higher level of LRF expression in the nucleus of LNCaP and PC-3 cells than RWPE-1 cells. A significant increase in LRF expression was observed with increasing doses of EGF in more aggressive and androgen-sensitive prostate cancer cells suggesting that EGF signaling pathway is critical in upregulating the expression of LRF/Pokemon to promote oncogenesis.
prostate cancer; Pokemon; EGF; LRF; ZBTB7
Vascular restenosis following coronary artery bypass graft can cause major clinical complications due to intimal hyperplasia in venous conduits. However, the precise underlying mechanisms of intimal hyperplasia are still unclear. We have recently reported that increased expression of connexin43 (Cx43) is involved in the proliferation of vascular smooth muscle cells (SMCs) in human saphenous vein (SV). In this study, we investigated the signaling transduction pathway involved in Cx43 expression and SV SMC proliferation. Angiotensin-II (AT-II, 100ng/ml) increased angiotensin II receptor 1 (AT-1R) protein expression and insulin-like growth factor-1 (IGF-1) (100ng/ml) upregulated IGF-1 receptor (IGF-1R) protein expression in SV SMCs. Interestingly, AT-1R expression was also increased by IGF-1 treatment, and IGF-1R expression was increased by AT-II treatment, which was blocked by siRNA-IGF-1R and siRNA-AT-1R respectively. Furthermore, the effect of AT-II and IGF-1 signal cross-talk inducing upregulation of their reciprocal receptors was blocked by siRNA against extracellular signal–regulated kinases 1/2 (Erk 1/2) in SMCs of saphenous vein. Moreover, AT-II and IGF-1 induced Cx43 expression via phosphorylation of Erk 1/2 and activation of transcription factor activator protein 1 (AP-1) through their reciprocal receptors in SV SMCs. These data demonstrate a cross-talk between IGF-1R and AT-1R in AT-II and IGF-1-induced Cx43 expression in SV SMCs involving Erk 1/2 and downstream activation of the AP-1 transcription factor.
Angiotensin II; Connexins; Intimal Hyperplasia; Restenosis; Vascular Smooth Muscle Cells; Vein Graft Disease
The growth and differentiation of cells is regulated by cytokines by binding to cell-surface receptors and activating intracellular signal transduction cascade. Suppressor of cytokine signaling (SOCS)-3 is a negative regulator of cytokines. In this study we examined the expression of SOCS3 in porcine coronary artery smooth muscle cells (PCASMCs) in vitro and in proliferating smooth muscle cells of neointimal lesions after coronary artery intervention in a swine model.
Methods and Results
PCASMCs were cultured and stimulated with TNF-α and/or IGF-1 individually or in combination. Protein expression of SOCS-3 was examined using Western blot. For in vivo studies, six female Yucatan miniswine were fed with special high cholesterol diet for 8 months. At 4 months of high cholesterol diet, animals underwent coronary balloon angioplasty. At the end of 8 months animals were euthanized, coronary arteries were isolated and morphological and histological studies were performed. Western blot data revealed significantly high SOCS-3 expression in PCASMCs in the presence of either TNF-α or IGF-1 (5–6 fold) alone. However, in the presence of both TNF-α and IGF-1 the SOCS-3 expression was significantly decreased (4–5 fold). Results from morphological studies including, H&E and Masson’s trichrome stain showed typical lesions with significant neointimal proliferation. Histological evaluation showed expression of smooth muscle α-actin and significantly increased proliferating cell nuclear antigen (PCNA) in neointimal lesion. Interestingly, there was significantly decreased expression of SOCS3 in smooth muscle cells of neointima as compared to control.
These data suggest that SOCS3 expression is decreased in proliferating smooth muscle cells of neointimal lesions. This leads to uncontrolled growth of vascular smooth muscle cells in injured arteries leading to restenosis. Therefore, local delivery of SOCS3 gene at the site of injury after coronary artery intervention could regulate the proliferation of vascular smooth muscle cells and help in preventing the neointimal hyperplasia and restenosis.
Angioplasty; Coronary Intervention; Inflammation; Intimal Hyperplasia; Restenosis; Suppressor of cytokine signaling-3
Cytokines released by the immune cells at the site of plaque milieu induce smooth muscle cell apoptosis to promote plaque instability. But, neuropeptide Y (NPY), a pleotropic factor, may modulate the effects of cytokines in atherosclerotic plaques of patients with carotid stenosis. Our aim was to investigate the relative expression of NPY-Y1, NPY-Y2 and NPY-Y5 receptors on carotid plaque vascular smooth muscle cells (pVSMCs) of symptomatic (S) and asymptomatic (AS) patients and examine the effect of inflammatory cytokines on the expression of NPY receptors, that may attenuate plaque rupture.
Methods and Results
In healthy carotid artery, there was significantly increased immunopositivity and increased mRNA transcripts of NPY-Y1 and NPY-Y5 receptors in thin sections and isolated VSMCs, respectively, compared to S and AS plaques. However, the NPY-Y2 expression was higher in S and AS pVSMCs than controls. Stimulation of the cells with TNF-α, IL-12 or IFN-γ (50 ng/ml) decreased mRNA transcripts of NPY-Y1 and NPY-Y5 and increased NPY-Y2 mRNAs in VSMCs of healthy carotid artery. The effect of the cytokines on mRNA transcripts of NPY-Y5 and NPY-Y2 in pVSMCs of S and AS patients was similar to healthy VSMCs, but with variable effect on NPY-Y1.
Increased expression of NPY-Y2 receptors in symptomatic pVSMCs than in healthy and asymptomatic subjects suggests a potential role of NPY-Y2 in plaque instability. This is further supported by the pronounced effect of atheroma-associated cytokines to increase NPY-Y2 mRNA transcripts in pVSMCs of patients with carotid stenosis.
Atheromatous cytokines; Atherosclerosis; Carotid plaque; Carotid stenosis; Neuropeptide Y; Smooth muscle cells
Angiopoietin (Ang)1 and Ang2 are ligands for Tie2 tyrosine kinase receptor (Tie2). Elevated levels of Ang1 and Ang2 in induced sputum of patients with asthma have been reported, with a positive correlation of Ang2 levels with the severity of airway occlusion. Although studies have shown Tie2-mediated regulation of nonvascular cells in some pathological conditions, current knowledge on Tie2 signaling in asthma is limited to the vasculature. We examined the expression pattern of Ang1, Ang2, vascular endothelial growth factor (VEGF), and Tie2 and their correlation with the degree of airway remodeling in the lung of ovalbumin (OVA)-sensitized and OVA-challenged mice with airway hyperresponsiveness. Lung tissues were isolated from Balb/c mice after OVA sensitization and challenge. Hematoxylin and eosin, periodic acid-Schiff, and trichrome staining were used to show the lung pathology. The expression of Ang1, Ang2, VEGF, and Tie2 was examined using immunofluorescence, Western blot, ELISA, and real-time PCR. In the lung of normal mice, Tie2 expression was detected only in the blood vessels. However, in the lung of OVA-sensitized and OVA-challenged mice, Tie2 was abundantly expressed in airway epithelial cells and in a subset of macrophages in addition to constitutive expression in pulmonary vessels. The increase in Tie2 expression correlated with the severity of airway remodeling. Macrophages and airway epithelial cells express Ang2 and VEGF only in allergic models. Ang1 was constitutively expressed, with a decrease in mRNA level in allergic models. In conclusion, increased expression of Tie2 and Ang2 in allergic airway epithelium and alveolar macrophages correlates with the severity of airway remodeling.
airway epithelial cells; airway remodeling; angiopoietins; Tie2 tyrosine kinase receptor; vascular endothelial growth factor
Apoptosis of vascular smooth muscle cells (SMCs) is controlled by a balance between the effect of growth factors and cytokines, and is involved in plaque instability in advanced atherosclerotic lesions. Recently, we reported high levels of atheroma-associated cytokines, including tumor necrosis factor-α (TNF-α), in carotid plaques of symptomatic patients. These cytokines induce apoptosis of vascular SMCs, and thus could be responsible for plaque rupture, a clinically devastating event. In this study, we examined the effect of TNF-α on the cell cycle inhibitor p27kip and apoptosis of SMCs in human carotid plaques, and the underlying mechanism. Both Forkhead box subclass o1 (FoxO1) and p27kip were more strongly expressed in symptomatic than asymptomatic atherosclerotic plaques. TNF-α significantly induced the expression of FoxO1 in asymptomatic plaque SMCs in a dose- and time-dependent manner via JNK signaling pathway. TNF-α also induced phosphorylation of FoxO1, resulting in its cytoplasmic translocation/nuclear exclusion of transcription factors. The effect of TNF-α was blocked by the PI3K inhibitor, LY294002. Meanwhile, TNF-α not only induced the p27kip expression and cell cycle arrest in G0–G1 phase, but also enhanced caspase-3 activity and induced apoptosis in SMCs of asymptomatic plaques. However, the potential effect of TNF-α on the cell cycle inhibitor p27kip and apoptosis of SMCs was inhibited by siRNA against FoxO1 in asymptomatic patients. These data suggest the involvement of FoxO1 transcription factor in TNF-α-induced expression of a cell cycle regulatory protein and apoptosis of SMCs, thus regulating the stability of atherosclerotic plaques with carotid stenosis.
Apoptosis; Atherosclerosis; Forkhead Transcription Factor; Plaque Stability; Vascular Smooth Muscle Cell
We previously reported that Fms-like tyrosine kinase 3 ligand (Flt3-L) reversed airway hyperresponsiveness (AHR) and airway inflammation, and increased the number of regulatory CD11chighCD8αhighCD11blow dendritic cells and CD4+CD25+ICOS+Foxp3+IL-10+ T-regulatory cells in the lung of allergen-sensitized and -challenged mice. In this study, we evaluated the effect of Flt3-L on Th17 cells and expression of suppressors of cytokine signaling (SOCS) proteins in the lungs of house dust mite (HDM)–sensitized and –challenged mice. BALB/c mice were sensitized and challenged with HDM, and AHR to methacholine was established. Mice were treated with Flt3-L (5 μg, intraperitoneal) daily for 10 days. Levels of IL-4, -5, -6, -8, and -13, and transforming growth factor (TGF)–β in the bronchoalveolar lavage fluid (BALF) were examined by ELISA. Flt3-L treatment reversed existing AHR to methacholine and substantially decreased eosinophils, neutrophils, IL-5, -6, -8, and IL-13, and TGF-β levels in the BALF. HDM-sensitized and -challenged mice showed a significant increase in lung CD4+IL-17+IL-23R+CD25− T cells with high expression of retinoic acid–related orphan receptor (ROR)–γt transcripts. However, administration of Flt3-L substantially decreased the number of lung CD4+IL-17+IL-23R+CD25− T cells, with significantly decreased expression of ROR-γt mRNA in these cells. HDM sensitization caused a significant increase in the expression of SOCS-1, -3, and -5 in the lung. Flt3-L treatment abolished the increase in SOCS-1 and SOCS-3 proteins, whereas SOCS-5 expression was significantly reduced. These data suggest that the therapeutic effect of Flt3-L in reversing the hallmarks of allergic asthma in a mouse model is mediated by decreasing IL-6 and TGF-β levels in the BALF, which, in turn, decrease CD4+IL-17+IL-23R+ROR-γt+CD25− T cells and the expression of SOCS-1 and SOCS-3 in the lung of HDM-sensitized and -challenged mice.
airway hyperresponsiveness; house dust mite; retinoic acid–related orphan receptor–γt; suppressors of cytokine signaling; T helper cell type 17
We recently reported that the adoptive transfer of T-regulatory cells (Tregs) isolated from lung and spleen tissue of green fluorescent protein–transgenic mice reversed airway hyperresponsiveness and airway inflammation. Because Programmed Death-1 (PD-1) is a pivotal receptor regulating effector T-cell activation by Tregs, we evaluated whether PD-1 is involved in the therapeutic effect of naturally occurring Tregs (NTregs) and inducible Tregs (iTregs) in cockroach (CRA)-sensitized and challenged mice. The CD4+CD25+ NTregs and CD4+CD25− iTregs isolated from the lungs and spleens of BALB/c mice were adoptively transferred into CRA-sensitized and CRA-challenged mice with and without anti–PD-1 antibody (100 μg/mice). The CD4+CD25+ T cells in the lung were phenotyped after adoptive transfer. Concentrations of IL-4, IL-5, IL-10, IFN-γ, and IL-13 in bronchoalveolar lavage fluid (BALF) were measured using ELISA. The NTregs and iTregs from either lung or spleen tissue reversed airway hyperresponsiveness for at least 4 wk. However, the therapeutic effect was blocked by administering the anti–PD-1 antibody. The administration of Tregs-recipient mice with anti–PD-1 antibody significantly decreased cytotoxic T-lymphocyte antigen-4 expression, with low concentrations of Forkhead-winged transcriptional factor box 3 (Foxp3) mRNA transcripts in lung CD4+CD25+ T cells. These mice had substantially higher concentrations of BALF IL-4, IL-5, and IL-13, but significantly decreased levels of BALF IL-10. Adoptive therapy recipients without the anti–PD-1 antibody exhibited high levels of CTLA-4 expression and Foxp3 transcripts in lung CD4+CD25+ T cells, with a significant decrease in BALF IL-4, IL-5, and IL-13 concentrations and a substantial increase in BALF IL-10 concentrations. These data suggest that the reversal of airway hyperresponsiveness and airway inflammation by Tregs is mediated in part by PD-1, because other costimulatory molecules (e.g., inducible costimulatory molecule [ICOS] or CTLA-4) have been shown to play a role in Treg-mediated suppression.
airway hyperresponsiveness; airway inflammation; anti–PD-1 antibody; cockroach antigen; Forkhead-winged transcriptional factor box P3
Coronary revascularization by coronary artery bypass grafting (CABG) is recommended in patients with recurrent myocardial ischemia. However, the long-term results of CABG using saphenous vein (SV) graft, compared to internal mammary artery (IMA) graft, have not been satisfactory. The SV graft failure is due to development of intimal hyperplasia, a process characterized by abnormal migration and proliferation of smooth muscle cells (SMCs) in the intimal layer of the vein graft. Insulin growth factor 1 (IGF-1) is a major mitogenic growth factor released at the site of the shear stress-induced graft injury. This study, for the first time, compares the extent of IGF-1-PI3K-Akt activation in isolated human by pass graft conduits. Human SV and IMA vessels were collected and SMCs isolated and cultured. In cultured SMCs, effect of IGF-1 was examined on total and phosphorylated PI3K, Akt and IGF-1R by Western blot analysis. Cell proliferation was measured using BrdU ELISA. There was no significant difference in the basal expression of phosphorylated PI3K, Akt and IGF-1R in SV and IMA SMCs from human bypass conduits. However, we observed an upregulation of IGF-1 receptors in the SV SMCs in response to IGF-1 stimulation with no effect in IMA SMCs. Furthermore, the immunoblotting and cellular activation of signaling ELISA (CASE) assay demonstrated a significantly higher activity of both PI3K and Akt in IGF-1-stimulated SV SMCs than IMA. This was inhibited by an IGF-1R blocking antibody. IGF-1 induced proliferation in both SV and IMA SMCs was inhibited by a PI3K inhibitor, wortmannin. These data demonstrate differential activity of IGF-1-induced PI3K-Akt activation, which was quantitatively and temporally greater in SV SMCs than in the IMA. This, at least in part, could explain the greater propensity of the SV conduits than the IMA to undergo intimal hyperplasia following CABG.
Coronary artery bypass graft; IGF-1; Internal mammary artery; Intimal hyperplasia; PI3K; Akt/PKB; Proliferation; Restenosis; Saphenous vein; Vascular smooth muscle cells
We previously reported in an ovalbumin-induced model of allergic asthma that Fms-like tyrosine kinase 3 ligand (Flt3-L) reversed airway hyperresponsiveness (AHR) and airway inflammation, and increased the number of regulatory CD11chighCD8αhighCD11blow dendritic cells in the lung. In this study, we investigated the effect of Flt3-L in a clinically relevant aeroallergen-induced asthma on the phenotypic expression of lung T cells. Balb/c mice were sensitized and challenged with cockroach antigen (CRA), and AHR to methacholine was established. These mice received three intraperitoneal injections of anti-CD25 antibody (PC61; 250 μg) and Flt3-L (3 μg) daily for 10 days. Cytokines and Ig levels in the serum were measured and differential bronchoalveolar lavage fluid (BALF) cell counts were examined. Flt3-L reversed AHR to methacholine to the control level. Flt3-L significantly decreased levels of BALF IL-5, IFN-γ, eosinophilia and substantially increased IL-10 and the number of CD4+CD25+ Forkhead winged helix transcription factor box P3 (Foxp3+) IL-10+ T cells in the lung. Administration of PC61 antibody blocked the effect of Flt3-L and substantially increased AHR, eosinophilia, and BALF IL-5 and IFN-γ levels, and decreased BALF IL-10 levels and the number of CD4+CD25+Foxp3+IL-10+ T cells. Flt3-L significantly decreased CD62-L, but increased inducible costimulatory molecule and Foxp3 mRNA expression in the CD4+CD25+ T cells isolated from lungs of Flt3-L–treated, CRA-sensitized mice compared to CRA-sensitized mice without Flt3-L treatment and PBS control group. Flt3-L significantly inhibited the effect of CRA sensitization and challenge to increase GATA3 expression in lung CD4+CD25+ T cells. Collectively, these data suggest that the therapeutic effect of Flt3-L is mediated by increased density of naturally occurring CD4+CD25+Foxp3+IL-10+ICOS+ T-regulatory cells in the lung. Flt3-L could be a therapeutic strategy for the management and prevention of allergic asthma.
airway hyperresponsiveness; anti-CD25 antibody; Fms-like tyrosine kinase 3 ligand; Forkhead winged helix transcription factor box P3; naturally occurring CD4+CD25+ T-regulatory cells
Rationale: T-regulatory cells (Tregs) are potent immunomodulators in allergic asthma.
Objectives: We evaluated the functional effects of Tregs by adoptively transferring naturally occurring CD4+CD25+ Tregs (NTregs) and CD4+CD25− inducible Tregs (iTregs) from lung and spleens of green fluorescent protein (GFP)-transgenic Balb/c mice into cockroach-sensitized and -challenged mice.
Methods: GFP-labeled NTregs and iTregs were adoptively transferred into cockroach-sensitized and -challenged mice. Airway hyperresponsiveness (AHR) to methacholine was examined using a single-chamber, whole-body plethysmograph and invasive tracheostomy.
Measurements and Main Results: Adoptive transfer of either NTregs or iTregs from lung or spleen reversed airway inflammation and AHR to methacholine, and the effect lasted for at least 4 weeks. GFP-labeled iTregs up-regulated CD25 and forkhead-winged transcriptional factor box protein 3 and migrated to lymph node and lung. Lung CD4+CD25+ T cells isolated from each group of recipient mice were inducible costimulatory molecule–high and programmed death (PD)-1–positive; however, higher expression of PD-1 was found in the spleen iTregs (S25−) and lung iTregs (L25−) groups. Higher levels of transforming growth factor–β and IL-10 mRNA transcripts and bronchoalveolar lavage fluid IL-10 and INF-γ levels were observed in lung CD4+CD25+ cells from the L25− and S25− cell-recipient mice than from lung NTregs (L25+) and spleen NTregs (S25+) cell-recipient mice. Adoptive transfer of either cell type significantly reduced bronchoalveolar lavage fluid IL-4, IL-5, and IL-13 levels.
Conclusions: Tregs reverse AHR and airway inflammation; however iTregs that differentiated into IL-10–producing CD4+ type 1 cells in the lung exert their suppressive activity likely by higher levels of transforming growth factor–β, IL-10, IFN-γ, and elevated levels of PD-1 compared with NTregs. Hence, PD-1 may be a conduit for reversing AHR by Tregs and a plausible target for treating asthma.
airway hyperresponsiveness; forkhead winged helix transcription factor box P3; inducible CD4+ CD25− T-regulatory cells; naturally occurring CD4+CD25+ T-regulatory cells; programmed death-1
Dendritic cell subsets display different functional role in regulating immune response and lead to various outcomes including Th1 versus Th2 or regulatory versus immunologic response. Administration of Flt3-Ligand prevents and reverses allergic airway inflammation and airway hyperresponsiveness in a mouse model. However, the underlying mechanisms are unclear.
We characterized and examined the role of lung dendritic cell subsets in the therapeutic effect of Flt3-Ligand.
Dendritic cells were isolated from the lungs of OVA-sensitized and challenged mice treated with rhFlt3-Ligand. Two populations of CD11c+ cells labeled with fluorochrome-conjugated antibodies were sorted. The ability of the purified cells to stimulate T cell proliferation and cytokine secretion pattern by different DC subsets was examined. Also, dendritic cells were adoptively transferred in mice to examine their effect on pulmonary function.
Two dendritic cell populations, CD11chighCD11blow and CD11clowCD11bhigh, were identified in the lungs of naïve and OVA-sensitized and challenged mice with and without treatment with Flt3-Ligand. The expression levels of CD8α, B220, CD19, F4/80, MHC II, CCR7, CD40, PDL1, PDL2, CD80, and CD86 were distinctly different between the two DC populations, which supports the notion that, CD11chighCD11blow and CD11clowCD11bhigh dendritic cells, potentially have regulatory and immunogenic properties, respectively. Administration of Flt3-Ligand increased the dendritic cells with regulatory potential in the lungs of antigen-sensitized mice, and CD11chighCD11blow dendritic cells acquired a maximum degree of regulatory capacity after Flt3-Ligand treatment.
These data suggest that Flt3-Ligand reverses airway hyperresponsiveness by regulating the function of lung dendritic cells in a mouse model of allergic airway inflammation.
Flt3-Ligand could be a potential immunomodulator in the treatment of established asthma.
Adoptive transfer; Airway hyperresponsiveness; Asthma; Dendritic cells; Flt3-Ligand; Mouse model; T cell Proliferation; Regulatory dendritic cells
Vascular remodeling and atheromatous lesion formation are determined in part by the balance between apoptosis and survival of vascular smooth muscle cells (VSMCs). In the chronic stages, apoptosis of VSMCs in the atherosclerotic plaques contributes to the weakening and potential rupture of the plaque causing pathologies such as acute coronary syndrome. The higher incidence of apoptosis in the plaques of symptomatic than in asymptomatic patients has been demonstrated, but the expression of survival proteins, including the inhibitor of apoptosis proteins (IAPs), has not been thoroughly examined. The aim of this study was to investigate the immunohistochemical expression of cellular inhibitor of apoptosis protein-2 (cIAP2), x-linked inhibitor of apoptosis protein (XIAP), and survivin in normal carotid arteries, and carotid endarterectomy specimens of symptomatic and asymptomatic patients with carotid stenosis. The results demonstrated stronger immunopositivity to smooth muscle myosin heavy chain antigen (SM-MHC) (sm2), proliferating cell nuclear antigen (PCNA), and p50 subunit of NF-κβ in the asymptomatic plaques than in symptomatic plaques. Furthermore, there was higher expression of cIAP2, XIAP, and survivin in the symptomatic than in the asymptomatic plaques and this paralleled caspase-3 expression. The increased expression of IAPs in symptomatic plaques could be due to endogenous defense mechanism to protect against the pro-apoptotic effect of the inflammatory stimuli that are released in the plaques. This could be involved in the stabilization of symptomatic atheromatous plaques and may prove a potential therapeutic target.
Apoptosis; Atherosclerosis; Carotid plaque; Carotid endarterectomy; Inhibitors of apoptosis; PCNA; Vascular smooth muscle cell
Dendritic cells (DCs) are unique antigen presenting cells that are immature prior to their encounter with an antigen. Exposure to allergens induces the maturation of DCs with changes in morphology and presence of dendrites. Here, we demonstrate that the DCs in the lungs of ovalbumin (OVA)-sensitized and challenged mice are more mature owing to their pronounced dendrites than the DCs in the lungs and spleen of PBS-treated mice, which are immature and possess cytoplasmic veils. Intermediate to these two groups are the DCs in the Flt3 ligand-treated group that exhibit comparatively fewer dendrites and cytoplasmic veils and hence are classified as semimature. Presence of large numbers of well developed mitochondria and rough endoplasmic reticulum in myeloid DCs from both lungs and spleen of OVA-sensitized and challenged mice indicate greater functional activity. Additionally, DCs from the OVA-sensitized and challenged mice also exhibit fat and glycogen stores, which are indicative of a mature population. In addition, treatment of the animals with Flt3 ligand attenuated airway hyperresponsiveness to methacholine in OVA-sensitized and challenged mice. These data suggest that morphological features could be indicative of the maturation and distinct functional state of DCs, and this could be associated with underlying mechanisms of Flt3 ligand-induced immunomodulation in allergic asthma.
Airway hyperresponsiveness; Allergy; Asthma; Cytoplasmic veils; Dendritic cells; Flt3 ligand; Immunomodulation; Morphology of dendritic cells
Ceramide, a sphingosine-based lipid molecule, has emerged as a key regulator of a wide spectrum of biological processes such as cellular differentiation, proliferation, apoptosis and senescence. Sphingomyelinase-dependent hydrolysis of sphingomyelin, and de novo synthesis involving the coordinated action of serinepalmitoyl transferase and ceramide synthase, are the two major pathways involved in ceramide synthesis. Clustering of plasma membrane rafts into ceramide enriched platforms serves as an important transmembrane signaling mechanism for cell surface receptors. Ceramides have been implicated in apoptosis, stress-signaling cascades as well as ion channels. There is accumulating evidence that targeted manipulation of ceramide metabolism pathway has immense therapeutic potential and may eventually prove to be a boon in the design of novel strategies and development of innovative treatments for diverse conditions including cardiovascular diseases, cancer and Alzheimer’s disease. As yet uncharacterized natural ceramide analogs and novel inhibitors of ceramide metabolism might prove to be potent drugs. In this review, we discuss significant advances that continue to provide intriguing insights into the complex cellular and molecular mechanisms underlying ceramide-mediated signaling cascades.
Apoptosis; Atherosclerosis; Cancer; Cardiovascular diseases; Ceramide; Ion channels; Neurodegeneration; Raft; Sphingomyelinase
The existence of Cl- channels in vascular smooth muscle cells (VSMCs) has been increasingly investigated, but the biological functions are not yet clear. Insulin-like growth factor (IGF)-I affects proliferation and migration of VSMCs, and dysregulation of this axis may be involved in atherogenesis and intimal hyperplasia. We examined the effects of Cl- channel blockers on IGF-I-induced proliferation in porcine VSMCs. The siRNA approach was used to support the role of ClC-2, a member of the volume-regulated Cl- channel family, in cell proliferation of VSMCs.
Method and Results
The IGF-I-induced VSMC proliferation was significantly suppressed by the Cl- channel blockers NPPB and IAA94 but not by DIDS. IGF-I-induced cell proliferation parallel a significant increase in the endogenous expression of ClC-2 mRNA and protein. Inhibitors of PI 3-kinase, LY294002 and wortmannin, significantly attenuated the IGF-I-upregulated ClC-2 expression and cell proliferation. We observed ClC-2-like Cl- current, and this current was augmented by IGF-I. SiRNA specifically targeted to ClC-2 abolished IGF-I-induced cell proliferation.
Our data demonstrate that ClC-2 plays a role in IGF-1-induced regulation of VSMC proliferation in cardiovascular diseases.
Atherosclerosis; voltage-gated Cl- channels; Cl- channel blocker; Proliferation; Vascular Smooth Muscle Cells
The POK family of proteins plays an important role in not only embryonic development and cell differentiation, but also in oncogenesis. Leukemia/lymphoma-related factor (LRF) belongs to the POK family of transcriptional repressors and is also known as POK erythroid myeloid ontogenic factor (POKEMON), which binds to short transcripts of HIV-1 (FBI-1) and TTF-1 interacting peptide (TIP21). Its oncogenic role is known only in lymphoma, non-small cell lung carcinoma, and malignant gliomas. The functional expression of LRF in human breast carcinoma has not yet been confirmed. The aim of this study was to investigate and compare the expression of LRF in human breast cancer tissues and other human tumors. The expression of LRF mRNA transcripts and protein was observed in twenty human benign and malignant breast biopsy tissues. Expression of LRF was observed in several formalin-fixed tissues by immunohistochemistry and immunofluorescence. All malignant breast tissues expressed mRNA transcripts and protein for LRF. However, 40% and 15% benign breast biopsy tissues expressed LRF mRNA transcripts and protein, respectively. The overall expression of LRF mRNA transcripts and total protein was significantly more in malignant breast tissues than the benign breast tissues. LRF expression was also observed in the nuclei of human colon, renal, lung, hepatocellular carcinomas and thymoma tumor cells. In general, a significantly higher expression of LRF was seen in malignant tissues than in the corresponding benign or normal tissue. Further studies are warranted to determine the malignant role of LRF in human breast carcinoma.
Breast Cancer; Pokemon; LRF; ZBTB7; POK
Advances have been made in defining the mechanisms for the control of allergic airway inflammation in response to inhaled antigens. Several genes, including ADAM33, DPP10, PHF11, GPRA, TIM-1, PDE4D, OPN3, and ORMDL3 have been implicated in the pathogenesis and susceptibility to atopy and asthma. Growing evidence associates asthma with a systemic propensity for allergic type 2 T-cell cytokines. Disordered coagulation and fibrinolysis also exacerbate asthma symptoms. Balance among functionally distinct dendritic cell subsets contribute to the outcome of T cell-mediated immunity. Allergen-specific T-regulatory cells play a pivotal role of in the development of tolerance to allergens and immune suppression. Major emphasis on immunotherapy for asthma during the past decade has been to direct the immune response to a type 1 response or immune tolerance. In this review article, we discuss the current information on the pathogenesis of allergic airway inflammation and potential immunotherapy, which could be beneficial in the treatment of airway inflammation, allergy, and asthma.