Cigarette Smoking Increases Abdominal and Visceral Obesity but Not Overall Fatness: An Observational Study

Background

Cigarette smoking and obesity are leading public health concerns. Both increase the risk for cardiovascular disease, cancer, and metabolic abnormalities. This study was conducted to assess the association between cigarette smoking and different types of obesity.

Methodology/Principal Findings

Two hundred eighty-three visitors to university hospitals located in four main provinces of South Korea were participated. All participants were classified as either current/past or never smokers and were divided into quartiles according to the total pack-years. Body mass index, waist circumference, total body fat percentage, and area of visceral and abdominal subcutaneous fat were measured. These results of each groups were compared. Waist circumference, and visceral fat area showed a J- or U-shaped association with total smoking amount during a lifetime. After restricting the analyses to past/current smokers, we found significant dose-dependent associations of smoking pack-years with abdominal and visceral obesity. Overall obesity measured by body mass index and total body fat percentage did not show such associations. Although current smokers clearly showed significant associations, we could not demonstrate these in past smokers, possibly because of the limited sample size.

Conclusions/Significance

Although smokers did not show significant difference in mean body mass index than those who never smoked, they showed more metabolically adverse fat distributions with increasing smoking amounts. This finding suggests that smoking is not beneficial for weight control. Therefore, smoking cessation and avoidance of smoking commencement should be addressed as important public health issues in preventing obesity and related complications.     

Sequence analysis of the 5′-flanking region of the gene encoding human N-acetylglucosaminyltransferase III

We have isolated and characterized the immediate (1651 bp) 5′-flanking region of the gene (GnT-III) encoding N-acetylglucosaminyltransferase III (GnT-III) from a human placental genomic library. Analysis of promoter elements shows a similarity to the 5′-flanking region of murine 1,4-galactosyltransferase. The sequence lacks obvious TATA elements and CCAAT boxes; however, putative regulatory sites, including 2 potential cAMP-response regulatory elements (CRE), 11 insulin-response element consensus sequences (IRE), 7 potential AP-2-binding sites, 2 SP1 consensus sequences (GC boxes) and 2 sequences similar to the half-palindromic glucocorticoid-responsive element (GRE), are present.     

The Sulfonylurea Receptor 1 (Sur1)-Transient Receptor Potential Melastatin 4 (Trpm4) Channel

The sulfonylurea receptor 1 (Sur1)-NC_Ca-ATP channel plays a central role in necrotic cell death in central nervous system (CNS) injury, including ischemic stroke, and traumatic brain and spinal cord injury. Here, we show that Sur1-NC_Ca-ATP channels are formed by co-assembly of Sur1 and transient receptor potential melastatin 4 (Trpm4). Co-expression of Sur1 and Trpm4 yielded Sur1-Trpm4 heteromers, as shown in experiments with Förster resonance energy transfer (FRET) and co-immunoprecipitation. Co-expression of Sur1 and Trpm4 also yielded functional Sur1-Trpm4 channels with biophysical properties of Trpm4 and pharmacological properties of Sur1. Co-assembly with Sur1 doubled the affinity of Trpm4 for calmodulin and doubled its sensitivity to intracellular calcium. Experiments with FRET and co-immunoprecipitation showed de novo appearance of Sur1-Trpm4 heteromers after spinal cord injury in rats. Our findings depart from the long-held view of an exclusive association between Sur1 and K_ATP channels and reveal an unexpected molecular partnership with far-ranging implications for CNS injury.     

Inhibition of Janus Kinase 1 synergizes docetaxel sensitivity in prostate cancer cells

Prostate cancer (PCa) is the second most common malignancy and is the fifth leading cause of cancer mortality among men globally. Docetaxel-based therapy remains the first-line treatment for metastatic castration-resistant prostate cancer. However, dose-limiting toxicity including neutropenia, myelosuppression and neurotoxicity is the major reason for docetaxel dose reductions and fewer cycles administered, despite a recent study showing a clear survival benefit with increased total number of docetaxel cycles in PCa patients. Although previous studies have attempted to improve the efficacy and reduce docetaxel toxicity through drug combination, no drug has yet demonstrated improved overall survival in clinical trial, highlighting the challenges of improving the activity of docetaxel monotherapy in PCa. Herein, we identified 15 lethality hits for which inhibition could enhance docetaxel sensitivity in PCa cells via a high-throughput kinome-wide loss-of-function screen. Further drug-gene interactions analyses identified Janus kinase 1 (JAK1) as a viable druggable target with existing experimental inhibitors and FDA-approved drugs. We demonstrated that depletion of endogenous JAK1 enhanced docetaxel-induced apoptosis in PCa cells. Furthermore, inhibition of JAK1/2 by baricitinib and ruxolitinib synergizes docetaxel sensitivity in both androgen receptor (AR)–negative DU145 and PC3 cells, but not in the AR-positive LNCaP cells. In contrast, no synergistic effects were observed in cells treated with JAK2-specific inhibitor, fedratinib, suggesting that the synergistic effects are mainly mediated through JAK1 inhibition. In conclusion, the combination therapy with JAK1 inhibitors and docetaxel could be a useful therapeutic strategy in the treatment of prostate cancers.     

Pentabromopseudilin: a myosin V inhibitor suppresses TGF-β activity by recruiting the type II TGF-β receptor to lysosomal degradation

Pentabromopseudilin (PBrP) is a marine antibiotic isolated from the marine bacteria Pseudomonas bromoutilis and Alteromonas luteoviolaceus. PBrP exhibits antimicrobial, anti-tumour, and phytotoxic activities. In mammalian cells, PBrP is known to act as a reversible and allosteric inhibitor of myosin Va (MyoVa). In this study, we report that PBrP is a potent inhibitor of transforming growth factor-β (TGF-β) activity. PBrP inhibits TGF-β-stimulated Smad2/3 phosphorylation, plasminogen activator inhibitor-1 (PAI-1) protein production and blocks TGF-β-induced epithelial–mesenchymal transition in epithelial cells. PBrP inhibits TGF-β signalling by reducing the cell-surface expression of type II TGF-β receptor (TβRII) and promotes receptor degradation. Gene silencing approaches suggest that MyoVa plays a crucial role in PBrP-induced TβRII turnover and the subsequent reduction of TGF-β signalling. Because, TGF-β signalling is crucial in the regulation of diverse pathophysiological processes such as tissue fibrosis and cancer development, PBrP should be further explored for its therapeutic role in treating fibrotic diseases and cancer.