Altered chromatin landscape in circulating T follicular helper and regulatory cells following grass pollen subcutaneous and sublingual immunotherapy

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Labeling of cells with ferumoxides-protamine sulfate complexes does not inhibit function or differentiation capacity of hematopoietic or mesenchymal stem cells

Two FDA-approved agents, ferumoxides (Feridex), a suspension of superparamagnetic iron oxide (SPIO) nanoparticles and protamine sulfate, a drug used to reverse heparin anticoagulation, can be complexed and used to label cells magnetically ex vivo. Labeling stem cells with ferumoxides-protamine sulfate (FePro) complexes allows for non-invasive monitoring by MRI. However, in order for stem cell trials or therapies to be effective, this labeling technique must not inhibit the ability of cells to differentiate. In this study, we examined the effect of FePro labeling on stem cell differentiation. Viability, phenotypic expression and differential capacity of FePro labeled CD34 + hematopoietic stem cells (HSC) and mesenchymal stem cells (MSC) were compared with unlabeled control cells. Colony-forming unit (CFU) assays showed that the capacity to differentiate was equivalent for labeled and unlabeled HSC. Furthermore, labeling did not alter expression of surface phenotypic markers (CD34, CD31, CXCR4, CD20, CD3 and CD14) on HSC, as measured by flow cytometry. SDF-1-induced HSC migration and HSC differentiation to dendritic cells were also unaffected by FePro labeling. Both FePro-labeled and unlabeled MSC were cultured in chondrogenesis-inducing conditions. Alcian blue staining for proteoglycans revealed similar chondrogenic differentiation for both FePro-labeled and unlabeled cells. Furthermore, collagen X proteins, indicators of cartilage formation, were detected at similar levels in both labeled and unlabeled cell pellets. Prussian blue staining confirmed that cells in labeled pellets contained iron oxide, whereas cells in unlabeled pellets did not. It is concluded that FePro labeling does not alter the function or differentiation capacity of HSC and MSC. These data increase confidence that MRI studies of FePro-labeled HSC or MSC will provide an accurate representation of in vivo trafficking of unlabeled cells.     

Metastatic Melanoma Presenting as Polymorphic Ventricular Tachycardia

A 41-year-old woman with metastatic melanoma was admitted to the hospital because of syncopal episodes, which had developed after the administration of an experimental chemotherapy agent that targeted Notch signaling, as part of a phase I clinical trial. Cardiac monitoring revealed recurrent episodes of polymorphic ventricular tachycardia correlating with the patient''s syncope. Investigations into the cause of the arrhythmia led to the discovery of metastatic lesions within the left ventricular myocardium. In presenting this case of polymorphic ventricular tachycardia as the antemortem clinical manifestation of metastatic melanoma involving the heart, we discuss the importance of recognizing that cardiac metastases can manifest themselves as arrhythmias in patients with malignant melanoma who are undergoing active anticancer treatment.Key words: Antineoplastic chemotherapy protocols/adverse effects, arrhythmias, cardiac/chemically induced/diagnosis/physiopathology/therapy, coronary disease/complications, heart neoplasms/pathology/secondary, melanoma/pathology, myocardium/pathology, receptors, notch/metabolism, recurrence/prevention & control, syncope/etiology, tachycardia, ventricular/chemically induced/etiologyA woman with metastatic melanoma was admitted to the hospital because of syncope and was diagnosed with episodes of polymorphic ventricular tachycardia (VT). The episodes developed after the administration of an experimental chemotherapy agent that targeted Notch signaling as part of a phase I clinical trial. The patient was found to have metastatic lesions in her myocardium. We present and discuss this case of polymorphic VT as a manifestation of cardiac metastasis in malignant melanoma in a patient who was undergoing active anticancer treatment.     

Regulation of EGFR Protein Stability by the HECT-type Ubiquitin Ligase SMURF2

Epidermal growth factor receptor (EGFR) is overexpressed in a variety of epithelial tumors and is considered to be an important therapeutic target. Although gene amplification is responsible for EGFR overexpression in certain human malignancies including lung and head and neck cancers, additional molecular mechanisms are likely. Here, we report a novel interaction of EGFR with an HECT-type ubiquitin ligase SMURF2, which can ubiquitinate, but stabilize EGFR by protecting it from c-Cbl-mediated degradation. Conversely, small interfering RNA (siRNA)-mediated knockdown of SMURF2 destabilized EGFR, induced an autophagic response and reduced the clonogenic survival of EGFR-expressing cancer cell lines, with minimal effects on EGFR-negative cancer cells, normal fibroblasts, and normal epithelial cells. UMSCC74B head and neck squamous cancer cells, which form aggressive tumors in nudemice, significantly lost in vivo tumor-forming ability on siRNA-mediated SMURF2 knockdown. Gene expressionmicroarray data from 443 lung adenocarcinoma patients, and tissue microarray data from 67 such patients, showed a strong correlation of expression between EGFR and SMURF2 at the messenger RNA and protein levels, respectively. Our findings suggest that SMURF2-mediated protective ubiquitination of EGFR may be responsible for EGFR overexpression in certain tumors and support targeting SMURF2-EGFR interaction as a novel therapeutic approach in treating EGFR-addicted tumors.     

Clinical and immunologic features of pediatric patients with common variable immunodeficiency and respiratory complications

BACKGROUND: Common variable immunodeficiency (CVID) is the term used to describe a heterogeneous group of B-cell deficiency syndromes characterized by hypogammaglobulinemia, impaired antibody production, and recurrent bacterial infections. OBJECTIVES: To determine the clinical manifestations and perform an immunological analysis of pediatric CVID patients suffering from respiratory complications. METHODS: The records of 10 patients with CVID who were followed up from 1992 to 2005 (6 males and 4 females) with a median (interquartile range) age of 13.9 (10.4-19.4) years were reviewed. All patients met the standard criteria set for CVID. RESULTS: Median total serum levels of immunoglobulin (Ig) G, IgM, and IgA in mg/dL were 383.5 (239.2-574.5), 32.5 (17.0-117.0), and 12.5 (5.0-30.7), respectively. Median age at the onset of symptoms, at CVID diagnosis, and on starting intravenous Ig therapy was 4.0 (0.8-6.2), 9.4 (6.7-11.3), and 9.1 (7.0-11.6) years, respectively. Associated disorders were recurrent infections (100%), bronchiectasis (90%), and growth failure (80%), whereas malabsorption, malignant neoplasm, inflammatory bowel disease, and autoimmune disorders were less common. All bronchiectatic patients had a low percentage of B cells, with an average of 4% (range, 1%-7%). The characteristic computed tomography finding in patients with CVID was a multilobar pattern. Malignant neoplasm developed an average of 11.5 (range, 6.5-20.2) years after the diagnosis of CVID was made. CONCLUSION: Recurrent respiratory infection should be evaluated to rule out CVID. Early diagnosis and intravenous Ig replacement therapy may reduce the frequency of respiratory infection. Low levels of serum Ig and percentage of B lymphocytes at diagnosis are important parameters for identifying patients at risk of structural lung damage.     

Non-Structural Proteins of Arthropod-Borne Bunyaviruses: Roles and Functions

Viruses within the Bunyaviridae family are tri-segmented, negative-stranded RNA viruses. The family includes several emerging and re-emerging viruses of humans, animals and plants, such as Rift Valley fever virus, Crimean-Congo hemorrhagic fever virus, La Crosse virus, Schmallenberg virus and tomato spotted wilt virus. Many bunyaviruses are arthropod-borne, so-called arboviruses. Depending on the genus, bunyaviruses encode, in addition to the RNA-dependent RNA polymerase and the different structural proteins, one or several non-structural proteins. These non-structural proteins are not always essential for virus growth and replication but can play an important role in viral pathogenesis through their interaction with the host innate immune system. In this review, we will summarize current knowledge and understanding of insect-borne bunyavirus non-structural protein function(s) in vertebrate, plant and arthropod.     

Heterozygotes of NOS3 polymorphisms contribute to reduced nitrogen oxides in high-altitude pulmonary edema

STUDY OBJECTIVES: High-altitude pulmonary edema (HAPE), which develops on exertion under hypoxic conditions, aggravates due to endothelial dysfunction. Repeat events of the disorder suggests of genetic susceptibility. Endothelial nitric oxide synthase gene (NOS3), a regulator of vasodilation, has emerged as a strong candidate marker. In the present study, we investigated G894T, 27-base-pair 4b/4a (variable number of tandem repeat), -922A/G, and -786T/C polymorphisms of NOS3, individually or in combination, for an association with HAPE. DESIGN: A cross-sectional case control study. SETTINGS: Blood samples of HAPE-resistant lowlanders (HAPE-r) were obtained at sea level, and blood samples of patients with HAPE (HAPE-p) were obtained at Sonam Norboo Memorial Hospital, Leh, at 3,500 m. PARTICIPANTS: The study groups consisted of 60 HAPE-r inducted two to three times to altitudes > 3,600 m; and 72 HAPE-p, who had HAPE on their first visit to high altitude. RESULTS: Nitrogen oxides (NOx) at 77.9 +/- 28.6 micromol/L were significantly elevated in HAPE-r as compared to 42.39 +/- 12.93 micromol/L in HAPE-p (p < 0.0001). Genotype distribution of G894T and 4b/4a polymorphisms was significantly different in the two groups (p = 0.001 and 0.009, respectively). Haplotype analysis revealed -922A/G and -786T/C polymorphisms in complete linkage disequilibrium. The wild-type haplotypes G-b (G894T, 4b/4a), G-A (G894T, -922A/G), and G-b-A (G894T, 4b/4a, -922A/G) were significantly overrepresented in HAPE-r (p < 0.0001, p = 0.03, and p = 0.02, respectively). The heterozygote genotype combination GTba as compared to wild-type combination GGbb was significantly higher in HAPE-p (chi2 = 18.62, p = 0.00009; odds ratio, 7.20; 95% confidence interval, 2.82 to 18.38). The combination of four heterozygotes GTbaAGTC was overrepresented in HAPE-p (p = 0.04), whereas the wild-type genotype combination GGbbAATT was overrepresented in HAPE-r (p = 0.002). Furthermore, the GGbb combination correlated with significantly elevated NOx as compared to remaining combinations as a whole in both HAPE-r and HAPE-p (p = 0.01 and 0.004, respectively). CONCLUSIONS: Reduced NOx and combination of heterozygotes associate with the susceptibility to HAPE. The study impels another step toward application of NOx as a diagnostic marker for HAPE. The NOS3 GTba and GTbaAGTC genotype combinations may find application as genetic markers for predicting the risk for HAPE.