Expression of a heat-inducible gene of the HSP70 family in human myelomonocytic cells: regulation by bacterial products and cytokines

Abstract

In this study we have examined the expression of a heat-shock protein (HSP) 70 gene in normal human peripheral blood leukocytes. Northern blot analysis showed that appreciable levels of hsp70 mRNA are present in monocytes and granulocytes, whereas transcript levels were barely detectable or absent in lymphocytes. Monocytes functionally activated by bacterial lipopolysaccharide (LPS) showed an early (15 minutes) increase of hsp70 transcripts that was shown, by actinomycin D blocking and nuclear run-off experiments, to be dependent on transcriptional activation of the gene. LPS did not appreciably affect the hsp70 mRNA half-life. Monocytes exposed to inactivated streptococci, phorbol-12- myristate-13-acetate, and tumor necrosis factor showed augmented levels of hsp70 transcripts, whereas interferon-gamma and monocyte, granulocyte, and granulocyte-monocyte colony-stimulating factors had no effect. Adherence to plastic augmented hsp70 expression in monocytes. S1 protection analysis indicated that the gene expressed in monocytes is indeed a heat-inducible member of the hsp70 gene family rather than a constitutively expressed heat-shock cognate gene. Western blot analysis showed that a heat-inducible HSP72 was present in monocytes and, at augmented levels, in LPS-treated monocytes. LPS-activated monocytes were more resistant to heat shock than unstimulated cells. These data indicate that a heat-inducible hsp70 gene can be efficiently expressed in myelomonocytic cells at physiologic temperatures. Expression of hsp70 genes in monocytes suggests a possible role of heat- inducible genes in the differentiation and/or functional activation of terminally differentiated nonproliferating elements of the myelomonocytic lineage.

Glutamine depletion impairs cellular stress response in human leucocytes

“…We found a rather low constitutive HSP70 expression in these cells. This is in accordance with mRNA data that show that HSP70 mRNA is barely detectable in unstressed human lymphocytes (Fincato et al 1991). Heat treatment at 428C, a temperature which is reached during a Fig.…”

Expression levels of hsc70 and hsp60 are developmentally regulated during B‐cell maturation and not associated to childhood c‐ALL at presentation or relapse

“… 2 Major heat shock inducible hsp70 (hsx70) previously identified in a similar 2‐D PAGE system using non hematopoietic cells (39), however, only barely detectable or absent in non‐stressed lymphoid cells (40) and not immunoprecipitated in non heat shocked leukemic BCPs (Fig. 3A, compare with Fig.…”

The Endosymbiotie Bacterium Holospora obtusa Enhances Heat‐Shock Gene Expression of the Host Paramecium caudatum

“…data). In mammals, expression of hsp70 and hsp‐related proteins are induced by bacterial glycoproteins, and they are thought to be the principal mediators of protection against endotoxemia (Fincato et al 1991; Heine et al 1999; Flohe et al 1999; Lau et al 2000). Thus, the glycoprotein se creted by Holospora might function as a stress factor for the host cell.…”