Increased agitation intensity increases CD13 receptor surface content and mRNA levels, and alters the metabolism of HL60 cells cultured in stirred tank bioreactors

Abstract

Flow cytometry and Northern blotting were used to examine the effects of hydrodynamic forces in stirred tank bioreactors on CD13 receptor surface content and mRNA levels of HL60 (human promyelocytic leukemia) cells. A step increase in agitation rate from 80 to 300 or 400 rpm reduced the apparent HL60 growth rate in a dose‐dependent manner. This step increase in agitation rate (to 300 or 400 rpm) also increased the CD13 receptor surface content on averge by 30% and 100%, respectively. This increase in CD13 receptor surface content was correlated with a 10% and a 60% increase in CD13 mRNA levels. We also observed a significant and very reproducible drop in CD13 expression over the course of a batch bioreactor run (80 rpm). Although we have no explanation for this, we show that the decrease in CD13 receptor surface content can be (at least partially, if not fully) explained by the corresponding decrease in CD13 mRNA. HL60 cell cultures agitated at 300 and 400 rpm exhibited glucose consumption and lactate production rates that were approximately 40% and 90% greater than values of the cultures agitated at 80 rpm. The physiological and practical implications of these results are discussed. © 1998 John Wiley & Sons, Inc. Biotechnol Bioeng 60: 239–250, 1998.

A comparative gene-expression analysis of CD34+ hematopoietic stem and progenitor cells grown in static and stirred culture systems

“…A low agitation rate has little effect on the expression of surface molecules and receptors on CD34 + HSPCs It was documented that the hydrodynamic forces produced by agitation influenced the transcriptional levels of cell surface receptors and changed the physiological response and proliferative potential, implying hydrodynamic force is an important operational parameter in the art of cell culture [5,6]. Furthermore, the proliferation of hematopoietic cells is dependent on the agitation rate and impellor configuration [2].…”

Decreasing Extracellular pH Increases CD13 Receptor Surface Content and Alters the Metabolism of HL60 Cells Cultured in Stirred Tank Bioreactors

“…Bioreactor Cultures. Bioreactor experiments were carried out in two Setric Genie 2‐L bioreactors (Setric Genie Industrial, Toulouse, France) as described in McDowell and Papoutsakis (24). Briefly, the reactors were seeded at an initial concentration of approximately (1.3−1.5) × 10 5 cells/mL, with an initial culture volume of 1.35 L, and grown at the nondamaging agitation rate of 80 rpm.…”

“…Additional samples were taken in parallel from the control and test cultures to determine nonspecific staining. Glucose and lactate concentrations of bioreactor samples were determined using a YSI model 2700 Biochemistry Analyzer (Yellow Springs Instrument Co., Yellow Springs, OH), as described in McDowell and Papoutsakis (24).…”

“…This work examines the effects of extracellular pH on the growth, viability, metabolism, and CD13 (aminopeptidase N) receptor surface content and mRNA levels of HL60 (promyelocytic leukemia) cells cultured under conditions of gentle agitation (80 rpm). This agitation intensity is necessary to achieve culture−pH homogeneity, yet gentle enough to avoid any detrimental effects on cells (23, 24). Duplicate paired‐bioreactor experiments, comparing extracellular pH 7.0 vs 7.4, and pH 7.2 vs 7.4 were performed.…”

“…However, CD13 is presumably not related to this differentiation. The choice of HL60 cells and the CD13 antigen as models for this research have been discussed (24).…”