Citations

Background— Mutations in genes including SCN5A encoding the α-subunit of the cardiac sodium channel (hNav1.5) cause Brugada syndrome via altered function of cardiac ion channels, but more than two-thirds of Brugada syndrome remains pathogenetically elusive. T-tubules and sarcoplasmic reticulum are essential in excitation of cardiomyocytes, and sarcolemmal membrane-associated protein (SLMAP) is a protein of unknown function localizing at T-tubules and sarcoplasmic reticulum. Methods and Results— We analyzed 190 unrelated Brugada syndrome patients for mutations in SLMAP . Two missense mutations, Val269Ile and Glu710Ala, were found in heterozygous state in 2 patients but were not found in healthy individuals. Membrane surface expression of hNav1.5 in the transfected cells was affected by the mutations, and silencing of mutant SLMAP by small interfering RNA rescued the surface expression of hNav1.5. Whole-cell patch-clamp recordings of hNav1.5-expressing cells transfected with mutant SLMAP confirmed the reduced hNav1.5 current. Conclusions— The mutations in SLMAP may cause Brugada syndrome via modulating the intracellular trafficking of hNav1.5 channel.

Abstract Even though mutations in epigenetic regulators frequently occur in myeloproliferative neoplasms, their effects on the epigenome have not been well studied. Furthermore, even though primary myelofibrosis (PMF) has a markedly worse prognosis than essential thrombocytosis or polycythemia vera, the molecular distinctions between these subgroups are not well elucidated. We conducted the HELP (HpaII tiny fragment enriched by LM-PCR) assay to study genome-wide methylation in polycythemia vera, essential thrombocytosis, and PMF samples compared with healthy controls. We determined that polycythemia vera and essential thrombocytosis are characterized by aberrant promoter hypermethylation, whereas PMF is an epigenetically distinct subgroup characterized by both aberrant hyper- and hypomethylation. Aberrant hypomethylation in PMF was seen to occur in non-CpG island loci, showing further qualitative differences between the disease subgroups. The differentially methylated genes in polycythemia vera and essential thrombocytosis were involved predominantly in cell signaling pathways and were enriched for binding sites of GATA1 and other transcription factors. In contrast, aberrantly methylated genes in PMF were involved in inflammatory pathways and were enriched for NF1, LEF1, and other transcription factors. Within the PMF subgroup, cases with ASXL1 disruptions formed an epigenetically distinct subgroup with relatively increased methylation. Cases of myeloproliferative neoplasms (MPN) with TET2 mutations showed decreased levels of hydroxymethylation and distinct set of hypermethylated genes. In contrast, the JAK2V617F mutation did not drive epigenetic clustering within MPNs. Finally, the significance of aberrant methylation was shown by sensitivity of MPN-derived cell lines to decitabine. These results show epigenetic differences between PMF and polycythemia vera/essential thrombocytosis and reveal methylomic signatures of ASXL1 and TET2 mutations. Cancer Res; 73(3); 1076–85. ©2012 AACR.

AbstractAimCurrent recommendations regarding the triage of patients with acute diverticulitis for inpatient or outpatient treatment are vague. We hypothesized that a significant number of patients treated as an inpatient could be managed as an outpatient.MethodA retrospective cohort study was carried out of 639 patients admitted for a first episode of diverticulitis. The diagnosis of acute diverticulitis was confirmed by computed tomography (CT). The endpoints included length of stay, need for surgery, percutaneous drainage and mortality. Patients were considered to have had a minimal hospitalization, defined as survival to discharge without needing a procedure, hospitalization of ≤ 3 days and no readmission for diverticulitis within 30 days after discharge.ResultsOf 639 patients, 368 (57.6%) had a minimal hospitalization. Female gender and CT scan findings of free air/fluid were negatively associated with the likelihood of minimal hospitalization. The presence of an abscess < 3 cm and stranding on CT did not predict the need for a higher level of care. Despite the statistical significance of several patient‐level predictors, the model did not identify patients likely to need only minimal hospitalization.ConclusionMost patients admitted with acute diverticulitis are discharged after minimal hospitalization. Free air/liquid in a patient admitted for acute diverticulitis indicates a more severe clinical course.

Bone marrow‐derived macrophages (BMMs) treated with granulocyte‐macrophage colony‐stimulating factor (GM‐CSF) or macrophage colony‐stimulating factor (M‐CSF), differentiate into GM‐CSF‐induced mouse bone marrow‐derived macrophages (GM‐BMMs) or M‐CSF‐induced mouse bone marrow‐derived macrophages (M‐BMMs), which have an M1 or M2 profile, respectively. GM‐BMMs produce large amounts of proinflammatory cytokines and mediate resistance to pathogens, whereas M‐BMMs produce antiinflammatory cytokines that contribute to tissue repair and remodeling. M‐BMMs stimulated with lipopolysaccharide (LPS) are in an antiinflammatory state, with an IL‐12lowIL‐10high phenotype. However, the regulation of this process remains unclear. Klf10 belongs to the family of Krüppel‐like transcription factors and was initially described as a TGF‐β inducible early gene 1. IL‐12p40 is upregulated in LPS‐stimulated M‐BMMs from Klf10‐deficient mice, but downregulated during Klf10 overexpression. Klf11, another member of the Krüppel‐like factor family, can also repress the production of IL‐12p40. Furthermore, Klf10 binds to the CACCC element of the IL‐12p40 promoter and inhibits its transcription. We have therefore identified Klf10 as a transcription factor that regulates the expression of IL‐12p40 in M‐BMMs.

AbstractBackgroundTransforming growth factor (TGF)‐β1 produced in airway epithelia has been suggested as a contributor to the airway remodeling observed in asthma patients. The protein tyrosine phosphatase SHP2 is a demonstrable modulator of TGF‐β1 production and thus a potential regulator of airway remodeling.ObjectivesTo define the signal event by which SHP2 regulates asthmatic responses in airway epithelial cells by using a mouse model of experimental OVA‐induced airway remodeling.MethodsThe airways of Shp2flox/flox mice were infected with recombinant adenovirus vectors expressing a Cre recombinase–green fluorescence protein (GFP) fusion protein as part of allergen provocation studies using mice sensitized with ovalbumin (OVA) and repeatedly challenged with OVA. Several endpoint pathologies were assessed, including airway hyper‐responsiveness (AHR), lung inflammatory score, peribronchial collagen deposition, and α‐smooth muscle actin (SMA) hyperplasia. In vitro studies using airway epithelial cells (BEAS‐2B) were used to investigate the role of SHP2 in the regulation of pulmonary remodeling events, including the expression of collagen, α‐SMA, and TGF‐β1.ResultsChronic OVA challenges in wild‐type mice resulted in airway remodeling and lung dysfunction (e.g., increased inflammatory scores, collagen deposition (fibrosis), smooth muscle hyperplasia, and a significant increase in AHR). These endpoint pathology metrics were each significantly attenuated by conditional shp2 gene knockdown in airway epithelia. In vitro studies using BEAS‐2B cells also demonstrated that the level of TGF‐β1 production by these cells correlated with the extent of shp2 gene expression.ConclusionsSHP2 activities in airway epithelial cells appear to modulate TGF‐β1 production and, in turn, regulate allergic airway remodeling following allergen provocation.Clinical ImplicationsOur findings identify SHP2 as a previously underappreciated contributor to the airway remodeling and lung dysfunction associated with allergen challenge. As such, SHP2 represents a potentially novel therapeutic target for the treatment of asthmatics.Capsule summaryAirway epithelial protein tyrosine phosphatase SHP2 appears to modulate TGF‐β1 activities as part of one or more cellular pathways leading to regulating the airway remodeling and lung dysfunction occurring in mouse models of allergic respiratory inflammation.