The deltaccr5 mutation conferring protection against HIV-1 in Caucasian populations has a single and recent origin in Northeastern Europe

The chemokine receptor CCR5 is encoded by the CMKBR5 gene located on the p21.3 region of human chromosome 3, and constitutes the major co- receptor for the macrophage-tropic strains of HIV-1. A mutant allele of the CCR5 gene, Delta ccr5 , was shown to provide to homozygotes with a strong resistance against infection by HIV. The frequency of the Delta ccr5 allele was investigated in 18 European populations. A North to South gradient was found, with the highest allele frequencies in Finnish and Mordvinian populations (16%), and the lowest in Sardinia (4%). Highly polymorphic microsatellites (IRI3.1, D3S4579 and IRI3.2, D3S4580 ) located respectively 11 kb upstream and 68 kb downstream of the CCR5 gene deletion were used to determine the haplotype of the chromosomes carrying the Delta ccr5 variant. A strong linkage disequilibrium was found between Delta ccr5 and specific alleles of the IRI3.1 and IRI3.2 microsatellites: >95% of the Delta ccr5 chromosomes carried the IRI3.1-0 allele, while 88% carried the IRI3.2-0 allele. These alleles were found respectively in only 2 or 1.5% of the chromosomes carrying a wild-type CCR5 gene. From these data, it was inferred that most, if not all Delta ccr5 alleles originate from a single mutation event, and that this mutation event probably took place a few thousand years ago in Northeastern Europe. The high frequency of the Delta ccr5 allele in Caucasian populations cannot be explained easily by random genetic drift, suggesting that a selection advantage is or has been associated with homo- or heterozygous carriers of the Delta ccr5 allele.      

12-Lipoxygenases and 12(S)-HETE: role in cancer metastasis

Arachidonic acid metabolites have been implicated in multiple steps of carcinogenesis. Their role in tumor cell metastasis, the ultimate challenge for the treatment of cancer patients, are however not well-documented. Arachidonic acid is primarily metabolized through three pathways, i.e., cyclooxygenase, lipoxygenase, and P450-dependent monooxygenase. In this review we focus our attention on one specific lipoxygenase, i.e., 12-lipoxygenase, and its potential role in modulating the metastatic process. In mammalian cells there exist three types of 12-lipoxygenases which differ in tissue distribution, preferential substrates, and profile of their metabolites. Most of these 12-lipoxygenases have been cloned and sequenced, and the molecular and biochemical determinants responsible for catalysis of specific substrates characterized. Solid tumor cells express 12-lipoxygenase mRNA, possess 12-lipoxygenase protein, and biosynthesize 12(S)-HETE [12(S)-hydroxyeicosatetraenoic acid], as revealed by numerous experimental approaches. The ability of tumor cells to generate 12(S)-HETE is positively correlated to their metastatic potential. A large collection of experimental data suggest that 12(S)-HETE is a crucial intracellular signaling molecule that activates protein kinase C and mediates the biological functions of many growth factors and cytokines such as bFGF, PDGF, EGF, and AMF. 12(S)-HETE plays a pivotal role in multiple steps of the metastatic cascade encompassing tumor cell-vasculature interactions, tumor cell motility, proteolysis, invasion, and angiogenesis. The fact that 12-lipoxygenase is expressed in a wide diversity of tumor cell lines and 12(S)-HETE is a key modulatory molecule in metastasis provides the rationale for targeting these molecules in anti-cancer and anti-metastasis therapeutic protocols.     

Adaption of Sprague Dawley rats to long-term feeding of high fat of high fructose diets

Summary Background Present animal models used to emulate type 2 diabetes may not accurately reflect the metabolic changes that occur in humans. Aims of the study The purpose of this research was to evaluate diets reported to induce insulin resistance and impaired glucose metabolism in rats as a potentially useful model for studying type 2 diabets. Methods Three groups of male Sprague Dawley rats (n=7) were fed either a control diet, based on AIN recommendations (53% cornstarch, 10% sucrose and 7% soybean oil), a high fat diet (25% soybean oil, 35% cornstarch) or a high fructose diet (53% fructose, 10% sucrose) for a 3 month period. Glucose tolerance tests were carried out in week 3 and week 9 of the experiment. At the termination of the experiment, serum insulin, glucose, cholesterol and triacylglycerols were measured. Glucose incorporation into glycogen and glycogen synthase activity were measured in soleus muscles. Results Similar weight gain was observed for all three groups of rats. Glucose tolerance curves and fasting glucose levels were not significantly different at any time point in the experiment. Insulin levels were unchanged for the controls (171±21 pM), high fructose (164±16 pM) and high fat (181±30 pM) diets. Fasting serum triacylglycerols and cholesterol levels were not significantly elevated by dietary treatment. In soleus muscles, rats on all three diets had a significant increase in glycogen synthesis in response to insulin, but synthesis was similar in all three groups. Glycogen synthase activity was also not significantly affected by long-term dietary intervention. Conclusions In this study, healthy Sprague Dawley rats fed high fat or high fructose diets for 3 months adapted to the nutritional intervention without developing classical signs of insulin resistance and impaired glucose tolerance. Received: 17 May 2000, Accepted: 31 August 2000     

Interactions of exogenous heparan sulfate with tumor cells of different metastatic phenotype

Heparan sulfate (HS) enhanced the growth of the highly metastatic (HM) 3LL cell line, but not that of the low metastatic (LM) counterpart, in a dose-dependent way. Heparin, chondroitin sulfate, hyaluronate did not produce this effect. At 4 degrees C both cell lines exhibited high affinity binding sites (Kd 10(-8) M) for exogenous HS. Unlike LM cells, the HM ones lost half of the surface-bound HS during the 24-hour incubation at 37 degrees C. HM cells in the exponential growth phase took up the bound HS at lower rate than the LM counterparts. Both cell lines fragmented the exogenous HS intracellularly, but only the HM cells were able to degrade it at the cell surface. The HM cells contained much more heparin-binding proteins--especially in the cell membrane and nuclear fraction--than the LM ones. These results clearly demonstrate that the interactions of tumor cells with exogenous HS are influenced by the invasive phenotype. We suggest also that there could be a correlation between the surface degradation, the slow uptake and the growth-promoting effect of the exogenous HS.     

Circulating endothelial progenitor cells and depression: a possible novel link between heart and soul

Although depression is known to be an independent risk factor for cardiovascular disorders, the mechanisms behind this connection are not well understood. However, the reduction in the number of endothelial progenitor cells (EPCs) in patients with cardiovascular risk factors has led us to hypothesize that depression influences the number of EPCs. EPCs labeled with CD34, CD133 and vascular endothelial growth factor receptor-2 (VEGFR2) antibodies were counted by flow cytometry in the peripheral blood (PB) of 33 patients with a current episode of major depression and of 16 control subjects. Mature (CD34+/VEGFR2+) and immature (CD133+/VEGFR2+) EPC counts were decreased in patients (vs controls; P<0.01 for both comparisons), and there was a significant inverse relationship between EPC levels and the severity of depressive symptoms (P<0.01 for both EPC phenotypes). Additionally, we assayed the plasma levels of VEGF, C-reactive protein (CRP) and tumor necrosis factor (TNF)-alpha and observed significantly elevated TNF-alpha concentrations in patients (vs controls; P<0.05) and, moreover, a significant inverse correlation between TNF-alpha and EPC levels (P<0.05). Moreover, by means of a quantitative RT-PCR approach, we measured CD34, CD133 and VEGFR2 mRNA levels of PB samples and found a net trend toward a decrease in all the investigated EPC-specific mRNA levels in patients as compared with controls. However, statistical significance was reached only for VEGFR2 and CD133 levels (P<0.01 for both markers). This is the first paper that demonstrates evidence of decreased numbers of circulating EPCs in patients with a current episode of major depression.     

12(S)-hydroxyeicosatetraenoic acid and 13(S)-hydroxyoctadecadienoic acid regulation of protein kinase C-alpha in melanoma cells: role of receptor-mediated hydrolysis of inositol phospholipids.

Protein kinase C (PKC) isoenzymes are essential components of cell signaling. In this study, we investigated the regulation of PKC-alpha in murine B16 amelanotic melanoma (B16a) cells by the monohydroxy fatty acids 12(S)-hydroxyeicosatetraenoic acid [12(S)-HETE] and 13(S)-hydroxyoctadecadienoic acid [13(S)-HODE]. 12(S)-HETE induced a translocation of PKC-alpha to the plasma membrane and focal adhesion plaques, leading to enhanced adhesion of B16a cells to the matrix protein fibronectin. However, 13(S)-HODE inhibited these 12(S)-HETE effects on PKC-alpha. A receptor-mediated mechanism of action for 12(S)-HETE and 13(S)-HODE is supported by the following findings. First, 12(S)-HETE triggered a rapid increase in cellular levels of diacylglycerol and inositol trisphosphate in B16a cells. 13(S)-HODE blocked the 12(S)-HETE-induced bursts of both second messengers. Second, the 12(S)-HETE-increased adhesion of B16a cells to fibronectin was sensitive to inhibition by a phospholipase C inhibitor and pertussis toxin. Finally, a high-affinity binding site (Kd = 1 nM) for 12(S)-HETE was detected in B16a cells, and binding of 12(S)-HETE to B16a cells was effectively inhibited by 13(S)-HODE (IC50 = 4 nM). In summary, our data provide evidence that regulation of PKC-alpha by 12(S)-HETE and 13(S)-HODE may be through a guanine nucleotide-binding protein-linked receptor-mediated hydrolysis of inositol phospholipids.     

The evidence for and against different modes of tumour cell extravasation in the lung: diapedesis,capillary destruction,necroptosis, and endothelialization

The development of lung metastasis is a significant negative prognostic factor for cancer patients. The extravasation phase of lung metastasis involves interactions of tumour cells with the pulmonary endothelium. These interactions may have broad biological and medical significance, with potential clinical implications ranging from the discovery of lung metastasis biomarkers to the identification of targets for intervention in preventing lung metastases. Because of the potential significance, the mechanisms of tumour cell extravasation require cautious, systematic studies. Here, we discuss the literature pertaining to the proposed mechanisms of extravasation and critically compare a recently proposed mechanism (tumour cell‐induced endothelial necroptosis) with the already described extravasation mechanisms in the lung. We also provide novel data that may help to explain the underlying physiological basis for endothelialization as a mechanism of tumour cell extravasation in the lung. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.