The regulation of TNF receptor mRNA synthesis, membrane expression, and release by PMA- and LPS-stimulated human monocytic THP-1 cells in vitro

Tetsuya Gatanaga,Chenduen Hwang,Maki Gatanaga,Fabio Cappuccini,Robert S Yamamoto,Gale A Granger

doi:10.1016/0008-8749(91)90127-w

Tetsuya Gatanaga, Chenduen Hwang + Show 4 more

Open Access

https://doi.org/10.1016/0008-8749(91)90127-w

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Abstract

The regulation of the 55-kDa TNF receptor (TNF-R) mRNA synthesis, membrane expression, and TNF binding factor (BF) release was examined in resting and activated human monocytic THP-1 and human promyelocytic leukemia HL-60 cells in vitro. Cells were activated with phorbol myristate acetate (PMA) and bacterial lipopolysaccharide (LPS). TNFα cytolytic activity in the supernatant of THP-1 cells stimulated by PMA began to appear at 4 hr, reached a peak at 8 hr, and declined by 12 hr. For THP-1 cells stimulated with LPS, the peak of TNFα activity appeared at 4 hr and then declined. TNFα-binding sites on the cell membrane were down-regulated within 1 hr after PMA and LPS treatment and then reappeared 12 hr later. Fifty-five-kilodalton TNF-R mRNA expression during this time period did not correlate with the level of membrane TNF-binding site expression. Additional studies indicated the presence of a 30-kDa TNF-BF in the supernatants which appeared after 24 hr. These data suggest that activated THP-1 and HL-60 cells are capable of releasing TNF-BF into the supernatant and this material may be involved in the control of secreted TNFα activities.

Highlights

Native tumor necrosis factor (TNFa) is a 55,000-MW trimer comprised of 17,350 MW peptides [1]
HL-60 cellsproduced TNFcr after treatment with an optimal dose of phorbol myristate acetate (PMA) (Fig. 1A, inset), but did not produce TNFa when stimulated with the levels of LPS we employed in thesestudies(data not shown)
As described under Materials and Methods, we examined whether the levels of mRNA transcript for 55-kDa TNF-R is affected when stimulated with PMA or LPS

Summary

INTRODUCTION

Native tumor necrosis factor (TNFa) is a 55,000-MW trimer comprised of 17,350 MW peptides [1]. Other groups have identified cell surface receptors in biological fluids that are released and bind to other biological response modifiers such as IL-2, IL-4, and growth factors [24,25,26] These studies have led to the concept that release of soluble receptors may represent a new mechanism to control cytokine activity. This concept is supported by the recent report of Gatanaga et al [23] that human soluble TNF-R can block the anti-tumor activity of recombinant human TNFa when injected into Meth-A tumor-bearing BALB/c mice. The present study was initiated to examine some of the stages in the synthesis of TNF-R message, membrane expression, and release of TNF-BF in the LPS- and PMA-stimulated macrophagelike cell lines THP- 1 and HL-60

MATERIALS AND METHODS

RESULTS

DISCUSSION