CRP and TNF-α Induce PAPP-A Expression in Human Peripheral Blood Mononuclear Cells

Objective. The effects of C-reactive protein (CRP) and tumor necrosis factor-α(TNF-α) on pregnancy-associated plasma protein-A (PAPP-A) expression in human peripheral blood mononuclear cells (PBMCs) require further investigation.Methods. The PAPP-A levels in culture supernatants, PAPP-A mRNA expression, and cellular PAPP-A expression were measured in human PBMCs isolated from fresh blood donations provided by 6 healthy volunteers (4 donations per volunteer). Analyses were conducted by ultrasensitive ELISA, western blotting, and RT-PCR following stimulation with CRP or TNF-αcytokines.Results. PAPP-A mRNA and protein levels after CRP stimulation peaked at 24 hours, whereas peak PAPP-A mRNA and protein levels were achieved after TNF-αstimulation at only 2 and 8 hours, respectively. These findings indicate the dose-dependent effect of CRP and TNF-αstimulation. Actinomycin D treatment completely prevented CRP and TNF-αinduction of PAPP-A mRNA and protein expression. Additionally, nuclear factor- (NF-)κB inhibitor (BAY11-7082) potently inhibited both CRP and TNF-αstimulated PAPP-A mRNA and protein expression.Conclusions. Human PBMCs are capable of expressing PAPP-Ain vitro, expression that may be regulated by CRP and TNF-αthrough the NF-κB pathway. This mechanism may play a significant role in the observed increase of serum PAPP-A levels in acute coronary syndrome (ACS).

Download Full-text

Mycoplasma fermentans infection promotes immortalization of human peripheral blood mononuclear cells in culture

Blood ◽

10.1182/blood-2004-04-1245 ◽

2004 ◽

Vol 104 (13) ◽

pp. 4252-4259 ◽

Cited By ~ 22

Author(s):

Shimin Zhang ◽

Shien Tsai ◽

Timothy T. Wu ◽

Bingjie Li ◽

James W.-K. Shih ◽

...

Keyword(s):

B Lymphocytes ◽

Peripheral Blood Mononuclear Cells ◽

Peripheral Blood ◽

Mononuclear Cells ◽

Human Peripheral Blood ◽

Human Pbmcs ◽

Peripheral Blood Mononuclear ◽

Mycoplasma Fermentans ◽

Cells In Culture ◽

Blood Mononuclear Cells

Abstract Chronic infection or colonization by mycoplasma(s) could gradually and significantly alter many biologic properties of mammalian host cells in culture, including induction of malignant transformation. We examined effects of Mycoplasma fermentans infection on the continuing survival and immortality of human peripheral blood mononuclear cells (PBMCs) from healthy blood donors. Without specific supplemental growth factors, human PBMCs normally die rapidly, with few cells other than macrophages/monocytes surviving after 2 weeks in cultures. Only occasional Epstein-Barr virus (EBV)–positive B lymphocytes would continue to proliferate and undergo spontaneous immortalization. Our present study revealed that infection of human PBMCs in culture with the incognitus and PG18 strains of M fermentans, but surprisingly not with some other strains tested in parallel, markedly enhanced the rate of EBV-positive B lymphocytes to undergo immortalization (74% vs 17%). Compared with spontaneously immortalized PBMCs, the PBMCs immortalized in cultures infected with the mycoplasmas often had prominent karyotype changes with chromosomal loss, gain, or translocations. Furthermore, many of these immortalized B lymphocytes were found to be monoclonal in nature. The in vitro findings would be of relevance to lymphoproliferative disorders that occurred in patients with immune suppression. The mycoplasma-mediated promotional effect in cell immortalization and its potential clinical implications warrant further study.

Download Full-text