No abstract

Studies suggest that Hsf4 expression correlates with its role in cell growth and differentiation. However, the role of Hsf4 in tumorigenesis in vivo remains unexplored. In this article, we provide evidence that absence of the Hsf4 gene suppresses evolution of spontaneous tumors arising in p53- or Arf-deficient mice. Furthermore, deletion of hsf4 alters the tumor spectrum by significantly inhibiting development of lymphomas that are normally observed in the majority of mice lacking p53 or Arf tumor suppressor genes. Using mouse embryo fibroblasts deficient in the hsf4 gene, we have found that these cells exhibit reduced proliferation that is associated with induction of senescence and senescence-associated β-galactosidase (SA-β-gal). Cellular senescence in hsf4-deficient cells is associated with the increased expression of the cyclin-dependent kinase inhibitors, p21 and p27 proteins. Consistent with the cellular senescence observed in vitro, specific normal tissues of hsf4−/− mice and tumors that arose in mice deficient in both hsf4 and p53 genes exhibit increased SA-β-gal activity and elevated levels of p27 compared with wild-type mice. These results suggest that hsf4 deletion-induced senescence is also present in vivo. Our results therefore indicate that Hsf4 is involved in modulation of cellular senescence, which can be exploited during cancer therapy.

Background: Obesity and type 2 diabetes mellitus are worldwide health problems, and lack of understanding of their linking mechanism is one reason for limited treatment options. We determined if genetic deletion of vimentin, a type 3 intermediate filament, affects obesity and type 2 diabetes mellitus. Methods: We fed vimentin-null (Vim −/−) mice and wild-type mice a high-fat diet (HFD) for 10 weeks and measured weight change, adiposity, blood lipids, and glucose. We performed intraperitoneal glucose tolerance tests and measured CD36, a major fatty acid translocase, and glucose transporter type 4 (GLUT4) in adipocytes from both groups of mice. Results: Vim −/− mice fed an HFD showed less weight gain, less adiposity, improved glucose tolerance, and lower serum level of fasting glucose. However, serum triglyceride and non-esterified fatty acid levels were higher in Vim −/− mice than in wild-type mice. Vimentin-null adipocytes showed 41.1% less CD36 on plasma membranes, 27% less uptake of fatty acids, and 50.3% less GLUT4, suggesting defects in intracellular trafficking of these molecules. Conclusion: We concluded that vimentin deficiency prevents obesity and insulin resistance in mice fed an HFD and suggest vimentin as a central mediator linking obesity and type 2 diabetes mellitus.

Atherosclerosis, the major pathology of cardiovascular disease, is caused by multiple factors involving psychological stress. Corticotropin-releasing hormone (CRH), which is released by neurosecretory cells in the hypothalamus, peripheral nerve terminals and epithelial cells, regulates various stress-related responses. Our current study aimed to verify the role of CRH in macrophage foam cell formation, the initial critical stage of atherosclerosis. Our quantitative real-time reverse transcriptase PCR (qRT-PCR), semi-quantitative reverse transcriptase PCR, and Western blot results indicate that CRH down-regulates ATP-binding cassette transporter-1 (ABCA1) and liver X receptor (LXR)-α, a transcription factor for ABCA1, in murine peritoneal macrophages and human monocyte-derived macrophages. Oil-red O (ORO) staining and intracellular cholesterol measurement of macrophages treated with or without oxidized LDL (oxLDL) and with or without CRH (10 nM) in the presence of apolipoprotein A1 (apoA1) revealed that CRH treatment promotes macrophage foam cell formation. The boron-dipyrromethene (BODIPY)-conjugated cholesterol efflux assay showed that CRH treatment reduces macrophage cholesterol efflux. Western blot analysis showed that CRH-induced down-regulation of ABCA1 is dependent on phosphorylation of Akt (Ser473) induced by interaction between CRH and CRH receptor 1(CRHR1). We conclude that activation of this pathway by CRH accelerates macrophage foam cell formation and may promote stress-related atherosclerosis.

Delineating the mechanisms that drive hepatic injury and hepatocellular carcinoma (HCC) progression is critical for development of novel treatments for recurrent and advanced HCC but also for the development of diagnostic and preventive strategies. Heat shock protein 70 (HSP70) acts in concert with several cochaperones and nucleotide exchange factors and plays an essential role in protein quality control that increases survival by protecting cells against environmental stressors. Specifically, the HSP70-mediated response has been implicated in the pathogenesis of cancer, but the specific mechanisms by which HSP70 may support malignant cell transformation remains to be fully elucidated. Here, we show that genetic ablation of HSP70 markedly impairs HCC initiation and progression by distinct but overlapping pathways. This includes the potentiation of the carcinogen-induced DNA damage response, at the tumor initiation stage, to increase the p53-dependent surveillance response leading to the cell cycle exit or death of genomically damaged differentiated pericentral hepatocytes, and this may also prevent their conversion into more proliferating HCC progenitor cells. Subsequently, activation of a mitogenactivated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) negative feedback pathway diminishes oncogenic signals, thereby attenuating premalignant cell transformation and tumor progression. Modulation of HSP70 function may be a strategy for interfering with oncogenic signals driving liver cell transformation and tumor progression, thus providing an opportunity for human cancer control.

Adipogenesis is a crucial cellular process that contributes to the expansion of adipose tissue in obesity. Shockwaves are mechanical stimuli that transmit signals to cause biological responses. The purpose of this study is to evaluate the effects of shockwaves on adipogenesis. We treated 3T3L-1 cells and human primary preadipocytes for differentiation with or without shockwaves. Western blots and quantitative real-time reverse transcriptase PCR (qRT-PCR) for adipocyte markers including peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT-enhancer-binding proteins (C/EBPα) were performed. Extracellular adenosine triphosphate (ATP) and intracellular cyclic adenosine monophosphate (cAMP) levels, which are known to affect adipocyte differentiation, were measured. Shockwave treatment decreased intracellular lipid droplet accumulation in primary human preadipocytes and 3T3-L1 cells after 11–12 days of differentiation. Levels of key adipogenic transcriptional factors PPARγ and/or C/EBPα were lower in shockwave-treated human primary preadipocytes and 3T3L-1 cells after 12–13 days of differentiation than in shockwave-untreated cells. Shockwave treatment induced release of extracellular ATP from preadipocytes and decreased intracellular cAMP levels. Shockwave-treated preadipocytes showed a higher level of β-catenin and less PPARγ expression than shockwave-untreated cells. Supplementation with 8-bromo-cAMP analog after shockwave treatment rescued adipocyte differentiation by preventing the effect of shockwaves on β-catenin, Wnt10b mRNA, and PPARγ expression. Low-energy shockwaves suppressed adipocyte differentiation by decreasing PPARγ. Our study suggests an insight into potential uses of shockwave-treatment for obesity.

Introduction: The clinical course of Graves’ disease (GD) treated with anti-thyroid drug (ATD) treatment were reviewed with the aim of establishing criteria able to predict intractable GD. Methods: The clinical course of 116 patients with GD who agreed to participate in this study between March 2009 and August 2019 in the pediatric endocrine clinic at Seoul St. Mary’s and St. Vincent’s Hospitals were reviewed. We defined an intractable as hyperthyroidism persistent over 2 years of ATD or relapsed after ATD withdrawal or had been treated ATD for at least 5 years [1-3]. Result: Of 116 patients diagnosed with GD, 37 patients (31.8%) had remission and 79 (68.2%) had intractable GD. Between intractable and remission GD group, there were no significant difference of female percentage, age at diagnosis, thyroid associated ophthalmopathy, serum levels of triiodothyronine (T3), free tetraiodothyronine (T4), Thyroid stimulating hormone (TSH) and positive rate of thyroid autoantibody (Thyroid peroxidase (TPO), Thyroglobulin (Tg), Thyroid stimulating hormone receptor (TSHR)). In intractable GD patients, the frequency of goiter at diagnosis is higher than remission group (89.9% [71/79] and 70.3% [26/37], P-value = 0.014). In correlation analysis, intractable GD showed positive correlation with goiter (R=0.247, P-value = 0.008). In multivariate logistic analyses, goiter is showed strong relationship with intractable GD (odds ratio, 3.793; 95% confidence interval, 1.367-10.524) after adjusting age and sex. Conclusion: Our study supported that goiter at initial presentation might be predicting factor for early onset intractable GD.

Vimentin is a type III intermediate filament protein expressed in cells of mesenchymal origin. Vimentin has been thought to function mainly as a structural protein and roles of vimentin in other cellular processes have not been extensively studied. Our current study aims to reveal functions of vimentin in macrophage foam cell formation, the critical stage of atherosclerosis. We demonstrated that vimentin null (Vim–/–) mouse peritoneal macrophages take up less oxidized LDL (oxLDL) than vimentin wild type (Vim+/+) macrophages. Despite less uptake of oxLDL in Vim–/– macrophages, Vim+/+ and Vim–/– macrophages did not show difference in expression of CD36 known to mediate oxLDL uptake. However, CD36 localized in plasma membrane was 50% less in Vim–/– macrophages than in Vim+/+ macrophages. OxLDL/CD36 interaction induced protein kinase A (PKA)-mediated vimentin (Ser72) phosphorylation. Cd36–/– macrophages did not exhibit vimentin phosphorylation (Ser72) in response to oxLDL. Experiments using phospho-mimetic mutation of vimentin revealed that macrophages with aspartate-substituted vimentin (V72D) showed more oxLDL uptake and membrane CD36. LDL receptor null (Ldlr–/–) mice reconstituted with Vim–/– bone marrow fed a western diet for 15 weeks showed 43% less atherosclerotic lesion formation than Ldlr–/– mice with Vim+/+ bone marrow. In addition, Apoe–/–Vim–/– (double null) mice fed a western diet for 15 weeks also showed 57% less atherosclerotic lesion formation than Apoe–/– and Vim+/+mice. We concluded that oxLDL via CD36 induces PKA-mediated phosphorylation of vimentin (Ser72) and phosphorylated vimentin (Ser72) directs CD36 trafficking to plasma membrane in macrophages. This study reveals a function of vimentin in CD36 trafficking and macrophage foam cell formation and may guide to establish a new strategy for the treatment of atherosclerosis.