Functional interrogation of a SARS-CoV-2 host protein interactome identifies unique and shared coronavirus host factors

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Role of iron in transferrin-dependent lymphocyte mitogenesis in serum-free medium

Transferrin can partially replace serum requirement for the mitogenic activity of both PHA and the oxidizing mitogen, neuraminidase and galactose oxidase, whereas several other proteins are inactive. Catalase enhances the potentiating effect of transferrin, indicating that transferrin stimulates hydrogen peroxide production by the cell preparations. Iron is required for transferrin to replace serum, since prior addition of desferrioxamine to medium or cell cultures eliminates the potentiating effect of transferrin on lymphocyte mitogenesis. In addition to the possibility that iron is required for nutritional purposes, transferrin-mediated activation of oxidative metabolism may have a stimulatory effect on lymphocyte activation.     

Ferro-mitogens: iron-containing compounds with lymphocyte-stimulatory properties

Ferric ammonium citrate (FAC) is nonmitogenic for human peripheral blood mononuclear cells (PBM) but has a potent mitogenic activity in the presence of IL-2. FAC in the presence of IL-2 increases the number of human peripheral blood mononuclear cells (PBM) expressing receptors for IL-2 and transferrin. FAC also markedly stimulates human PBM treated with supraoptimal, nonmitogenic concentrations of Con A. FAC, in the presence of IL-2, is a T-cell mitogen with a stringent requirement for macrophages. FAC stimulates the production of TNF-alpha and IFN-gamma in human PBM, and this effect is potentiated by IL-2. Thiourea and 3-amino-1,2,4-triazole selectively inhibit mitogenesis induced by FAC, indicating that oxygen radicals or peroxidase may mediate the triggering signal induced by this mitogen. In addition to hemin, as we have previously reported, and FAC, a variety of iron-containing proteins have lymphocyte stimulatory properties in combination with IL-2. They include horseradish peroxidase, cytochrome c, myoglobin, and transferrin. We have given the name ferro-mitogens to this group of compounds.     

Inhibition of β-adrenergic stimulation of lymphocyte adenylate cyclase by phorbol myristate acetate is mediated by activated macrophages

Phorbol myristate acetate, a tumor promoter and lymphocyte mitogen, inhibits isoproterenol-stimulated adenylate cyclase in human peripheral blood mononuclear cells. Catalase and superoxide dismutase and depletion of macrophages from the cell preparations reversed this inhibitory effect. Phorbol myristate acetate did not inhibit isoproterenol-stimulated adenylate cyclase in purified T-cells or in membrane preparation from turkey erythrocytes. Thus, inhibition of adenylate cyclase activity by phorbol myristate acetate in human peripheral blood mononuclear cells is an indirect effect resulting from production of oxy radicals by activated macrophages.     

Varying course of pancytopenia after busulfan treatment of chronic myelocytic leukemia (CML)]

In 84 patients with chronic myeloid leukaemia receiving a cytostatic monotherapy with busulfan, an aplastic syndrome developed which was confirmed by a biopsy of the pelvis crest and examination of the sternal marrow. The time interval until pancytopenia was detected varied considerably in each case, ranging between 6 and 126 months. There are no correlations to the initial doses of busulfan. 3 patients died of the immediate effects of the bone-marrow damage caused by busulfan. In 4 from 6 of the following pancytopenic patients the leukocyte values lay between 12,800/microliter and 80,400 microliter when busulfan adminstration was interrupted. Thus, it is scarcely possible to give any reliable informations about a leukocyte limit value as a standard for an interruption of therapy in order to prevent bone-marrow aplasia. Taking this into account, the conclusion may be drawn that relatively short control intervals have to be made in this monochemotherapy of CML which often can be used successfully for many years.     

Altered nucleic acid contents of mononuclear cells in blood of renal allograft recipients

The DNA and RNA contents of blood mononuclear cell populations of 29 cadaver renal allograft recipients and 49 blood donors (controls) were estimated by acridine orange flow cytometry (AO FCM) to assess their cell cycle status. All patients received azathioprine and prednisone for immunosuppression. The patients represented three clinical categories: clinically stable patients, those with acute rejections (clinically overt or impending), and those with infections. Three cell cycle compartments were analyzed for percentage (%) and RNA content (R) of cells: G0/1, consisting of all cells with diploid DNA content; 2 S.D., consisting of cells with diploid DNA content and RNA content 2 standard deviations above the mean RNA content of controls; and SG2M, consisting of cells with a DNA content higher than that of G0/1 cells. The relative coefficient of variation (rCV) of the DNA distribution of G0/1 cells was also determined. In such cell cycle evaluations, the means of rCV and SG2M% of stable recipients were significantly different from those of blood donors. Multivariate analysis of the variables of the three categories of patients resulted in the tentative formulation of two simple logistic equations: one that differentiates stable patients from those with impending or overt rejections based on 2SD% and another one that distinguishes infected patients from those with impending or overt rejections based on SG2M% and RG0/1.     

Ultrastructural variation of Blastocystis hominis stocks in culture

An ultrastructural study of 10 different Blastocystis hominis stocks was undertaken. Three distinct morphological forms, vacuolar, granular and amoeboid, were distinguished. Numerous variations in the organelles and general cell structure were observed between stocks. B. hominis displayed considerable size variation in the vacuolar forms, ranging from 4 to 63 micron. Thickness and density of the surface coat varied between different stocks. Beneath the surface coat the bilaminar cell membrane displayed electron-dense pits. The nature and quantity of the vacuolar contents varied, and in the granular form four morphologically different inclusions were seen. The organelles which showed the greatest variation between stocks were the mitochondria, varying in shape, electron-density, type of cristae and presence of inclusions. There was minimal variation between stocks with regard to endoplasmic reticulum, Golgi complex and nuclei. Budding of material between the cytoplasm and central vacuole was observed in some stocks. Indications of phagocytic behaviour of B. hominis were seen in the amoeboid form and in the vacuolar form of one stock.     

Dissection of corticotropin‐releasing factor system involvement in locomotor sensitivity to methamphetamine

Sensitivity to the euphoric and locomotor‐activating effects of drugs of abuse may contribute to risk for excessive use and addiction. Repeated administration of psychostimulants such as methamphetamine (MA) can result in neuroadaptive consequences that manifest behaviorally as a progressive escalation of locomotor activation, termed psychomotor sensitization. The present studies addressed the involvement of specific components of the corticotropin‐releasing factor (CRF) system in locomotor activation and psychomotor sensitization induced by MA (1, 2 mg/kg) by utilizing pharmacological approaches, as well as a series of genetic knockout (KO) mice, each deficient for a single component of the CRF system: CRF‐R1, CRF‐R2, CRF, or the CRF‐related peptide Urocortin 1 (Ucn1). CRF‐R1 KO mice did not differ from wild‐type mice in sensitization to MA, and pharmacological blockade of CRF‐R1 with CP‐154,526 (15, 30 mg/kg) in DBA/2J mice did not selectively attenuate either the acquisition or expression of MA‐induced sensitization. Deletion of either of the endogenous ligands of CRF‐R1 (CRF, Ucn1) either enhanced or had no effect on MA‐induced sensitization, providing further evidence against a role for CRF‐R1 signaling. Interestingly, deletion of CRF‐R2 attenuated MA‐induced locomotor activation, elucidating a novel contribution of the CRF system to MA sensitivity, and suggesting the participation of the endogenous urocortin peptides Ucn2 and Ucn3. Immunohistochemistry for Fos was used to visualize neural activation underlying CRF‐R2‐dependent sensitivity to MA, identifying the basolateral and central nuclei of the amygdala as neural substrates involved in this response. Our results support further examination of CRF‐R2 involvement in neural processes associated with MA addiction.     

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