Oxidized LDL induces vimentin secretion by macrophages and contributes to atherosclerotic inflammation.

Activated macrophages show increased expression of vimentin, an intermediate filament protein. Macrophages secrete vimentin into extracellular space; however, the functions of extracellular vimentin and the process of vimentin secretion are not clearly defined. We found that oxidized low-density lipoproteins (oxLDL) via CD36 induced vimentin secretion in macrophages. We also revealed that extracellular vimentin induced macrophages to release inflammatory cytokines and augmented oxLDL-induced release of TNF-α and IL-6. Extracellular vimentin activated NF-κB signaling via phosphorylation of focal adhesion kinase (p-FAK) and IκB kinase (p-IκK). Extracellular vimentin also amplified the oxLDL-induced p-IκK increase and IκB decrease. Vimentin-induced TNF-α release was not dependent on Dectin-1, which is known to bind vimentin. We measured serum vimentin concentrations and found that patients with atherosclerotic coronary artery disease had higher levels of serum vimentin than normal subjects. Circulating oxLDL and vimentin concentrations showed a high degree of correlation. In mouse experiments, vimentin concentration was higher in the sera of apoE null mice with western diet-induced atherosclerosis than in the sera of chow diet-fed apoE null mice without atherosclerosis. We concluded that vimentin is secreted by oxLDL/CD36 interaction in macrophages and extracellular vimentin promotes macrophage release of pro-inflammatory cytokines. This may contribute to atherosclerotic inflammation and based on our analysis of serum vimentin, we suggest serum vimentin as a predictive marker for atherosclerosis. KEY MESSAGES: OxLDL via CD36 induces secretion of vimentin, a cytoskeletal protein in macrophages. Extracellular vimentin induces macrophages to release proinflammatory cytokines such as tumor necrotizing factor-alpha (TNF-α) and this process is mediated by activation of focal adhesion kinase (FAK) and NF-ƙB signaling. Serum concentrations of vimentin in coronary artery disease patients are higher than that in control group. Vimentin concentration is strongly correlated with oxLDL concentration in serum.

Shockwaves Suppress Adipocyte Differentiation via Decrease in PPARγ.

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 ß-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 ß-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.

The Molecular Chaperone Heat Shock Protein 70 Controls Liver Cancer Initiation and Progression by Regulating Adaptive DNA Damage and Mitogen-Activated Protein Kinase/Extracellular Signal-Regulated Kinase Signaling Pathways.

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 mitogen-activated 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.

Corticotropin-Releasing Hormone (CRH) Promotes Macrophage Foam Cell Formation via Reduced Expression of ATP Binding Cassette Transporter-1 (ABCA1).

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.

Cerebral salt-wasting syndrome after hematopoietic stem cell transplantation in adolescents: 3 case reports.

Cerebral salt-wasting syndrome (CSWS) is a rare disease characterized by a extracellular volume depletion and hyponatremia induced by marked natriuresis. It is mainly reported in patients who experience a central nervous system insult, such as cerebral hemorrhage or encephalitis. The syndrome of inappropriate antidiuretic hormone secretion is a main cause of severe hyponatremia after hematopoietic stem cell transplantation, whereas CSWS is rarely reported. We report 3 patients with childhood acute leukemia who developed CSWS with central nervous system complication after hematopoietic stem cell transplantation. The diagnosis of CSW was made on the basis of severe hyponatremia accompanied by increased urine output with clinical signs of dehydration. All patients showed elevated natriuretic peptide and normal antidiuretic hormone. Aggressive water and sodium replacement treatment was instituted in all 3 patients and 2 of them were effectively recovered, the other one was required to add fludrocortisone administration.

Cushing syndrome secondary to CRH-producing Wilms tumor in a 6 year old.

Abstract Cushing syndrome is caused by prolonged exposure to elevated serum cortisol. It is uncommon in children, and etiology includes pituitary adenoma, adrenal tumor, and exogenous glucocorticoid administration. Rarely, it is paraneoplastic in origin. We present a case of paraneoplastic Cushing syndrome due to Wilms tumor that secreted corticotropin-releasing hormone (CRH). A 6-year-old male presented with polyphagia and weight gain. He showed Cushingoid appearance, hypertension, and palpable left flank mass. Serum cortisol and adrenocorticotropic hormone (ACTH) levels were elevated. Computed tomography showed a neoplasm originating from the left kidney. Pathologic diagnosis of Wilms tumor was made upon nephroureterectomy. Immunohistochemical staining was positive for CRH and negative for ACTH. All features of Cushing syndrome disappeared after surgery. This represents a rare case of Cushing syndrome secondary to Wilms tumor in which CRH production has been demonstrated.

Inactivation of heat shock factor Hsf4 induces cellular senescence and suppresses tumorigenesis in vivo.

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 ß-galactosidase (SA-ß-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-ß-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.

Primary ovarian dysfunction after hematopoietic stem cell transplantation during childhood: busulfan-based conditioning is a major concern.

We evaluated the incidence of patient/treatment factors associated with primary ovarian failure (POF) after hematopoietic stem cell transplantation (HSCT) during childhood. Fifty girls over 12 years of age (15.0 +/- 2.2) who were referred to the pediatric endocrinology clinic between March 2002 and March 2010 after HSCT at the Catholic HSCT center were enrolled in the study. In total, 36 (72%) out of 50 patients developed POF. Twenty-three patients were diagnosed and treated as chronic graft-versus-host disease. As preparative regimens for HSCT, 23 patients received total body irradiation (TBI)-based regimen, 19 received busulfan (BU)-based regimen, 4 received both BU- and TBI-based, and 4 received reduced intensity conditioning regimen. In a univariate logistic regression analysis, the BU-based regimen (p = 0.028) showed a strong relationship with POF. The incidence of POF according to the route of BU administration, between orally and intravenously, were not different (p = 0.435). These results emphasize the importance of monitoring these patients at regular intervals and the need to develop complementary HSCT protocols for preventing POF in children.