The association of serum ferritin and transferrin receptor concentrations with mortality in women with human immunodeficiency virus infection.

BACKGROUND AND OBJECTIVES: Whether degree of iron stores influences progression of human immunodeficiency virus (HIV) disease is controversial. We studied the relationship of indirect measures of iron stores with mortality in highly active antiretroviral therapy (HAART)-naive participants from the Women's Interagency HIV Study. DESIGN AND METHODS: One hundred and fifty-eight HIV-infected women who died before July 1996 were individually matched by CD4+ cell count (within +/- 50 cells/mL) and HIV RNA level (within +/- 0.50 log10 copies/mL) to 154 controls. Serum ferritin and transferrin receptor concentrations were measured in 151 pairs of women. Results. Using multivariable conditional logistic regression models that were adjusted for self-reported antiretroviral therapy use, age, smoking status, ethnicity, hemoglobin concentration, C-reactive protein and aspartate amino transferase, a log10 increase in baseline serum ferritin concentration was associated with a 1.67-fold increase in the odds of death (95% CI: 0.98, 2.86) and a one-unit decrease in transferrin receptor to log10 ferritin ratio was associated with a 1.12-fold (95% CI: 1.01, 1.23) increase in the odds of death. INTERPRETATIONS AND CONCLUSIONS: In this study, higher indirect measures of iron status were associated with reduced survival among HAART-naive HIV-infected women. Additional prospective studies with data on direct measures of iron status along with randomized trials are needed to elucidate the current equipoise over whether iron supplementation is beneficial by preventing anemia or harmful by increasing iron stores in HIV-infected women.

HIV-1 Tat interacts with LIS1 protein.

BACKGROUND: HIV-1 Tat activates transcription of HIV-1 viral genes by inducing phosphorylation of the C-terminal domain (CTD) of RNA polymerase II (RNAPII). Tat can also disturb cellular metabolism by inhibiting proliferation of antigen-specific T lymphocytes and by inducing cellular apoptosis. Tat-induced apoptosis of T-cells is attributed, in part, to the distortion of microtubules polymerization. LIS1 is a microtubule-associated protein that facilitates microtubule polymerization. RESULTS: We identified here LIS1 as a Tat-interacting protein during extensive biochemical fractionation of T-cell extracts. We found several proteins to co-purify with a Tat-associated RNAPII CTD kinase activity including LIS1, CDK7, cyclin H, and MAT1. Tat interacted with LIS1 but not with CDK7, cyclin H or MAT1 in vitro. LIS1 also co-immunoprecipitated with Tat expressed in HeLa cells. Further, LIS1 interacted with Tat in a yeast two-hybrid system. CONCLUSION: Our results indicate that Tat interacts with LIS1 in vitro and in vivo and that this interaction might contribute to the effect of Tat on microtubule formation.

Nuclear protein phosphatase-1 regulates HIV-1 transcription.

We recently reported that protein phosphatase 1 (PP1) dephosphorylates RNA polymerase II C-terminal repeats and regulates HIV-1 transcription in vitro. Here we provide evidence that PP1 is also required for Tat-induced HIV-1 transcription and for viral replication in cultured cells. Inhibition of PP1 by overexpression of nuclear inhibitor of PP1 (NIPP1) inhibited Tat-induced HIV-1 transcription in transient transfection assays. A mutant of NIPP1 that was defective in binding to PP1 did not have this effect. Also the co-expression of PP1 gamma reversed the inhibitory effect of NIPP1. Adeno-associated virus-mediated delivery of NIPP1 significantly reduced HIV-1 transcription induced by Tat-expressing adenovirus in CD4+ HeLa cells that contained an integrated HIV-1 promoter (HeLa MAGI cells). In addition, infection of HeLa MAGI cells with adeno-associated virus-NIPP1 prior to the infection with HIV-1 significantly reduced the level of HIV-1 replication. Our results indicate that PP1 might be a host cell factor that is required for HIV-1 viral transcription. Therefore, nuclear PP1 may represent a novel target for anti-HIV-1 therapeutics.

Congenital disorder of oxygen sensing: association of the homozygous Chuvash polycythemia VHL mutation with thrombosis and vascular abnormalities but not tumors.

Adaptation to hypoxia is critical for survival and regulates multiple processes, including erythropoiesis and vasculogenesis. Chuvash polycythemia is a hypoxia-sensing disorder characterized by homozygous mutation (598C>T) of von Hippel-Lindau gene (VHL), a negative regulator of hypoxia sensing. Although endemic to the Chuvash population of Russia, this mutation occurs worldwide and originates from a single ancient event. That VHL 598C>T homozygosity causes elevated normoxic levels of the transcription factor hypoxia inducible factor-1alpha (HIF-1alpha), serum erythropoietin and hemoglobin is known, but the disease phenotype has not been documented in a controlled manner. In this matched cohort study, VHL 598C>T homozygosity was associated with vertebral hemangiomas, varicose veins, lower blood pressures, and elevated serum vascular endothelial growth factor (VEGF) concentrations (P <.0005), as well as premature mortality related to cerebral vascular events and peripheral thrombosis. Spinocerebellar hemangioblastomas, renal carcinomas, and pheochromocytomas typical of classical VHL syndrome were not found, suggesting that overexpression of HIF-1alpha and VEGF is not sufficient for tumorigenesis. Although hemoglobin-adjusted serum erythropoietin concentrations were approximately 10-fold higher in VHL 598C>T homozygotes than in controls, erythropoietin response to hypoxia was identical. Thus, Chuvash polycythemia is a distinct VHL syndrome manifested by thrombosis, vascular abnormalities, and intact hypoxic regulation despite increased basal expression of hypoxia-regulated genes.