Several recent reports support the hypothesis that apoptosis occurring in leukocytes of human immunodeficiency virus type 1 (HIV-1)-infected individuals is important in progression to AIDS. Specifically, apoptosis of uninfected bystander cells appears critical in the pathogenesis of disease. Here, we present evidence that protease-defective, gp120-containing HIV-1 (L-2) particle preparations sp...

Phagocytic cells, including normal human blood neutrophils and monocytes, metabolize 25-hydroxyvitamin D3 in vitro to more polar metabolites. Cells of the human monoblastic cell line U937 produced three metabolites when incubated with 25-hydroxyvitamin D3. One of these metabolites, previously designated peak III, has its maximal absorbance at 310 nm. Mass spectral analysis of the trimethylsilyl...

U937 monocytic cells are shown here to express a range of PDE4, cAMP-specific phosphodiesterase (PDE) isoenzymes: the long isoenzymes, PDE4A4, PDE4D5 and PDE4D3, plus the short isoenzyme, PDE4B2. These isoenzymes provide around 76% of the total cAMP PDE activity of U937 cells. The specific activities of the total PDE4A, PDE4B and PDE4D activities were 0.63+/-0.09, 8.8+/-0.2 and 34.4+/-2.9 pmol/...

The immunomodulatory hormone 1.25-dihydroxyvitamin D3 (1,25-(OH)2D3) has been shown to suppress T-cell proliferation and interleukin-2 synthesis as well as 6-cell immunoglobulin synthesis, while stimulating many macrophage functions. We have previously shown increased synthesis of interleukin-1f3 in lipopolysaccharide (LPS)-stimulated U937 cells after pretreatment with 10 nmol/L 1,25-(0H)2D~. W...

TNF-alpha transduces signals of survival or death via its two receptors, R1/p55/p60 and RII/p80/p75. The role of caspases as effectors of cell death is universally accepted, although caspase inhibitors may potentiate TNF cytotoxicity in some instances. In conditions when macromolecular synthesis is blocked, caspases are part of the machinery that executes TNF-triggered apoptotic death in U937, ...

The inhibition of transcription factor functions was used to define their role in phorbol ester-induced cellular differentiation of a monocytic cell line, U937. We demonstrate a differential effect on cell adhesion and differentiation: antisense or competitive binding with double-stranded oligonucleotides antagonized the functions of AP-1, NF-kappaB, and PU.1 transcriptional factors. In the pre...

AIM Dietary supplements in polyunsaturated fatty acids (PUFA), particularly omega-3, are well known for their beneficial effects in preventing cardiovascular diseases (CVD). The aim of this study was to determine the role of PUFA on the modulation of apoptosis induced by hypochlorous acidoxidized LDL (HOCl-oxLDL) in U937 cells. METHODS We tested the effect of monocyte cell line U937 supplemen...