Effect of BIS depletion on HSF1-dependent transcriptional activation in A549 non-small cell lung cancer cells

The expression of BCL-2 interacting cell death suppressor (BIS), an anti-stress or anti-apoptotic protein, has been shown to be regulated at the transcriptional level by heat shock factor 1 (HSF1) upon various stresses. Recently, HSF1 was also shown to bind to BIS, but the significance of these protein-protein interactions on HSF1 activity has not been fully defined. In the present study, we observed that complete depletion of BIS using a CRISPR/Cas9 system in A549 non-small cell lung cancer did not affect the induction of heat shock protein (HSP) 70 and HSP27 mRNAs under various stress conditions such as heat shock, proteotoxic stress, and oxidative stress. The lack of a functional association of BIS with HSF1 activity was also demonstrated by transient downregulation of BIS by siRNA in A549 and U87 glioblastoma cells. Endogenous BIS mRNA levels were significantly suppressed in BIS knockout (KO) A549 cells compared to BIS wild type (WT) A549 cells at the constitutive and inducible levels. The promoter activities of BIS and HSP70 as well as the degradation rate of BIS mRNA were not influenced by depletion of BIS. In addition, the expression levels of the mutant BIS construct, in which 14 bp were deleted as in BIS-KO A549 cells, were not different from those of the WT BIS construct, indicating that mRNA stability was not the mechanism for autoregulation of BIS. Our results suggested that BIS was not required for HSF1 activity, but was required for its own expression, which involved an HSF1-independent pathway.

ERK-mediated phosphorylation of BIS regulates nuclear translocation of HSF1 under oxidative stress

B-cell lymphoma (BCL)-2-interacting cell death suppressor (BIS) has diverse cellular functions depending on its binding partners. However, little is known about the effects of biochemical modification of BIS on its various activities under oxidative stress conditions. In this study, we showed that H₂O₂ reduced BIS mobility on SDS–polyacrylamide gels in a time-dependent manner via the activation of extracellular signaling-regulated kinase (ERK). The combined results of mass spectroscopy and computational prediction identified Thr285 and Ser289 in BIS as candidate residues for phosphorylation by ERK under oxidative stress conditions. Deletion of these sites resulted in a partial reduction in the H₂O₂-induced mobility shift relative to that of the wild-type BIS protein; overexpression of the deletion mutant sensitized A172 cells to H₂O₂-induced cell death without increasing the level of intracellular reactive oxygen species. Expression of the BIS deletion mutant decreased the level of heat shock protein (HSP) 70 mRNA following H₂O₂ treatment, which was accompanied by impaired nuclear translocation of heat shock transcription factor (HSF) 1. Co-immunoprecipitation assays revealed that the binding of wild-type BIS to HSF1 was decreased by oxidative stress, while the binding of the BIS deletion mutant to HSF1 was not affected. These results indicate that ERK-dependent phosphorylation of BIS has a role in the regulation of nuclear translocation of HSF1 likely through modulation of its interaction affinity with HSF1, which affects HSP70 expression and sensitivity to oxidative stress.

Pharmaco-mechanical Thrombectomy and Stent Placement in Patients with May-Thurner Syndrome and Lower Extremity Deep Venous Thrombosis / 대한흉부외과학회지

BACKGROUND: Compression of the left common iliac vein by the overriding common iliac artery is frequently combined with acute deep vein thrombosis in patients with May-Thurner Syndrome. We evaluate the results of treatment with thrombolysis and thrombectomy followed by stenting in 34 patients with May-Thurner Syndrome combined with lower extremity deep venous thrombosis. MATERIAL AND METHOD: The authors retrospectively reviewed the records of 34 patients (mean age: 65+/-14 year old) who had undergone stent insertion for acute deep vein thrombosis that was caused by May-Thurner syndrome. After thrombectomy and thrombolysis, insertion of a wall stent and balloon angioplasty were performed to relieve the compression of the left common iliac vein. Urokinase at a rate of 80,000 to 120,000 U/hour was infused into the thrombosed vein via a multi-side hole thrombolysis catheter. A retrieval inferior vena cava (IVC) filter was placed to protect against pulmonary embolism in 30 patients (88%). Oral anticoagulation with warfarin was maintained for 3 months, and follow-up Multi Detector Computerized Tomography (MDCT) angiography was done at the date of the patients' hospital discharge and at the 6 months follow-up. RESULT: The symptoms of deep venous thrombosis disappeared in two patients (4%), and there was clinical improvement within 48 hours in twenty eight patients (82%), but there was no improvement in four patients (8%). The MDCT angiography at discharge showed no thrombus in 9 patients (26%) and partial thrombus in 21 (62%), whereas the follow-up MDCT at 6.4+/-5.5 months (32 patients) revealed no thrombus in 23 patients (72%), and partial thrombus in 9 patients (26%). Two patients (6%) had recurrence of DVT, so they underwent retreatment. CONCLUSION: Stent insertion with catheter-directed thrombolysis and thrombectomy is an effective treatment for May-Thurner syndrome combined with acute deep vein thrombosis in the lower extremity.

Glycobiology of Selectin / 한국유방암학회지

Selectins, carbohydrate-binding molecules, bind to fucosylated and sialylated glycoprotein ligands, and are found on endothelial cells, leukocytes and platelets. They can be classified into E-, L- and P-selectins, and are involved in trafficking of cells of the innate immune system, T lymphocytes and platelets via binding with specific ligands. An absence of selectins or selectin ligands has serious consequences in mice or humans, leading to recurrent bacterial infections and persistent disease. Selectins are involved in constitutive lymphocyte homing and chronic and acute inflammation processes, including post-ischemic inflammation in muscle, kidney, heart, skin inflammation, atherosclerosis, glomerulonephritis and lupus erythematosus. Selectin-neutralizing monoclonal antibodies, recombinant soluble P-selectin glycoprotein ligand 1 and small-molecule inhibitors of selectins have been tested in clinical trials on patients with multiple trauma, cardiac indications and pediatric asthma, respectively. Anti-selectin antibodies have also been successfully used in preclinical models to deliver imaging contrast agents and therapeutics to sites of inflammation. The contributions of selectins and selectin ligands to signalling deserve further study, which will allow a much more detailed analysis of the contributions of selectins in models of inflammation, haemostasis, haematopoiesis, wound healing, atherogenesis, and tumor metastasis.

Sarcoidosis with cardiac involvement

Patients with significant cardiac sarcoidosis are at increased risk of sudden death from ventricular dysrhythmias or conduction disturbances. We report a patient in whom there was radiographic and histologic evidence of systemic sarcoidosis; though histologic confirmation of involvement of heart by sarcoidosis is lacking, the clinical manifestations, radionuclide image findings, rhythm disturbances, and the response to steroid therapy are strong evidence in favor of myocardial involvement by the granulomatous process.