Changes in phosphorylated heat-shock protein 27 in response to acute ureteral obstruction in rats

AIM

In vivo, renal medullary interstitial cells (RMICs) and collecting duct principal cells (mpkCCD cells) are subjected to inflammatory, oxidative and mechanical stress as a result of unilateral ureteral obstruction (UUO). Because heat-shock protein (HSP) 27 and HSP70 are induced by cellular stresses and play a role in cytoprotection, we hypothesized that HSP27 and HSP70 are increased in rats subjected to acute UUO and in RMICs and mpkCCD cells exposed to inflammatory, oxidative or mechanical stress.

METHODS

Rats were subjected to acute UUO for 6 h and 12 h. To examine the expression of HSP27, phosphorylated HSP27 (pHSP27) and HSP70 in response to inflammatory, oxidative and mechanical stress in vitro, we exposed RMICs and mpkCCD cells to interleukin 1β (IL-1β), hydrogen peroxide (H2 O2 ), and stretch stimulation over time.

RESULTS

The phosphorylated form of HSP27 (pHSP27) was increased in the renal inner medulla (IM) after 6-h and 12-h UUO, while HSP27 and HSP70 were unchanged. Furthermore, after 6 h and 12 h of UUO, the expression of inflammatory (IL-1β) and oxidative [haem oxygenase 1 (HO-1)] markers was induced. Exposure to inflammatory, oxidative and mechanical stress changed HSP27 and pHSP27 expression in RMICs but not in mpkCCD cells, while HSP70 was not affected by any of the stress conditions. Exposure of RMICs to oxidative and mechanical stress induced HSP27 phosphorylation via a p38-dependent mechanism.

CONCLUSION

These data demonstrate that, in response to acute UUO, different forms of cellular stresses modulate HSP27 expression and phosphorylation in RMICs. This may affect the ability of renal cells to mount an effective cytoprotective response.

Modulatory function on autologous myeloid progenitor cells of clonal T-lymphocytes following autologous bone marrow transplantation

We have studied the regulatory capacity of clonal T-lymphocytes from patients undergoing autologous bone marrow transplantation (ABMT) on the generation of CFU-GM from their harvest marrow preparations. To this end, T-lymphocytes from peripheral blood from 5 patients undergoing ABMT isolated 10 d before and 7, 14 and 28 d post-ABMT were placed in limiting dilution conditions (384 wells for each patient at each time point) and polyclonally stimulated. From more than 1600 wells with growth from the 5 patients, preparations from more than 900 wells could be expanded (range between patients 33-452) and identified by immunophenotyping (IP) and flow cytometry (FCM) by their exclusive expression of CD4 or CD8. This was significantly fewer than seen in normal donors, especially so at d 7 and 14 post-ABMT The ratio between CD4+ and CD8+ clones varied between 0.6 and 2.8 (median 1.3) and was significantly lower in the patients compared to normal donors (median 3.1; range 3.0-6.5). When the clonal T-cell preparations were co-cultured with autologous bone marrow cells obtained at the time of harvest and depleted for T-lymphocytes, the vast majority of both CD4+ and CD8+ clones exerted a clear enhancement on the CFU-GM growth with no relation to time of blood sampling in its the magnitude. Moreover, a trend seen in the normal donors towards CD4+ clones being more effective in this enhancement was not observed in ABMT patients. We conclude that clonal T-cells from ABMT patients, irrespective of their phenotype and time of isolation, exert an enhancement on the growth of autologous CFU-GM, which is equal to that seen in normal donors.

Delineation of erythropoiesis in normal and malignant bone marrow using monoclonal antibody AS-E1 directed against transferrin receptors (CD71)

We have delineated the erythropoietic compartment in normal and malignant bone marrow (BM) by using the monoclonal antibody (mAb) AS-E1 directed against the transferrin receptor by flow cytometric (FCM) analysis. In normal BM we found a bimodal expression in antigen density with a minor subset (approximately 3%) expressing AS-E1high and a larger subset (approximately 15%) expressing AS-E1low. By fluorescence activated cell sorting, morphological examination of smears stained by immunocytochemistry and by BFU-E assays the AS-E1high fraction was shown to contain cells of erythroid origin (proerythroblasts, basophilic erythroblasts and polychromatic erythroblasts), whereas the AS-E1low fraction consisted mainly of promyelocytes and myelocytes. In patients with malignant hematological disorders we found a more pronounced heterogeneity in the density and the degree of AS-E1low expression compared to normal BM, and to further characterize the AS-E1low cells in patients and to exclude that this broad reactivity interfered with the identification of the AS-E1high cells, we employed triple-color FCM assays with mAbs directed against the myeloid surface markers CD13 and CD66 in addition to AS-E1. In all patients we found that 80-90% of the AS-E1low cells co-expressed CD13 and/or CD66 and thus were of myeloid origin. Finally, we evaluated 2 methods for determination of the AS-E1high subset and found an assay involving forward light scatter and logAS-E1 density to be sufficient. We conclude that AS-E1high is a valid FCM marker for the normal erythropoiesis.

[Experience with special classes for mildly brain-damaged children with behavior disorders]

Within the framework of a large-scale medical and pedagogical experiment conducted at Rostock, two special education classes for second graders were set up at the start of the 1965/66 school year in an attempt to prevent children with cerebral lesions from failing to pass courses already in the lower grades at elementary schools. As a result of this experiment, it was decided to start a school for special education children, and this school now has two parallel classes each for second, third, and fourth graders as well as one additional class in which pupils are prepared for the fifth normal education school grade. Psychological tests made as part of a longitudinal study in which 48 children who had been to this school from 1965, 1966, and 1967 were included and which spread over years including the 1971/72 school years, showed an improvement in motor development with slightly retarded intellectual development and unchanged lack of concentration power. Average attainments in the various subjects improved while pupils were attending special education classes and did not, after reintegration of such children into normal schools (fifth grade), drop below the general level of proficiency.