MicroRNA-146a reduces MHC-II expression via targeting JAK/STAT signaling in dendritic cells after stem cell transplantation.

Acute Graft-versus-host disease (GVHD) is a major immunological complication after allogeneic hematopoietic cell transplantation and a better understanding of the molecular regulation of the disease could help to develop novel targeted therapies. Here we found that a G/C polymorphism within the human microRNA-146a (miR-146a) gene of transplant recipients, which causes reduced miR-146a levels, was strongly associated with the risk of developing severe acute GVHD (n=289). In mice, deficiency of miR-146a in the hematopoietic system or transfer of recipient-type miR-146a-/- dendritic cells (DCs) enhanced GVHD, while miR-146a mimic-transfected DCs ameliorated disease. Mechanistically, lack of miR-146a enhanced JAK2-STAT1 pathway activity, which led to higher expression of class II-transactivator (CIITA) and consecutively increased MHCII-levels on DCs. Inhibition of JAK1/2 or CIITA knockdown in DCs prevented miR-146a-/- DC-induced GVHD exacerbation. Consistent with our findings in mice, patients with the miR-146a polymorphism rs2910164 in hematopoietic cells displayed higher MHCII levels on monocytes, which could be targeted by JAK1/2 inhibition. Our findings indicate that the miR-146a polymorphism rs2910164 identifies patients at high risk for GVHD before allo-HCT. Functionally we show that miR-146a acts as a central regulator of recipient-type DC activation during GVHD by dampening the pro-inflammatory JAK-STAT/CIITA/MHCII axis, which provides a scientific rationale for early JAK1/2 inhibition in selected patients.

[Observational study of the tolerance and effectiveness of cefpodoxim-proxetil in general practice]. / Beobachtungsstudie zur Verträglichkeit und Wirksamkeit von Cefpodoxim-Proxetil in der Praxis.

BACKGROUND, OUTCOME AND METHODS: Observational study of the clinical efficacy and tolerance of the cefpodoxime proxetil preparation, Podomexef. The study was conducted from August 1996 to April 1997. A total of 549 practitioners participated, 2,734 patients were recruited, and the data of 2714 patients were analyzed. DOSAGE: Podomexef 200 film tablets, 2x daily. INDICATION: Bacterial infections of the upper and lower airways and ENT infections. RESULTS: Global clinical efficacy was assessed by the physicians to be "very good" and "good" in 96.4% of the cases. With regard to tolerance, the physicians' assessment was "very good" and "good" in 96.3%. In 51 patients (1.9%), 70 adverse drug reactions involving the gastrointestinal tract, CNS and skin occurred. CONCLUSION: Under day-to-day doctor's office conditions, Podomexef 200 film tablets are both effective and well tolerated in the treatment of bacterial infections of the airways and ENT infections.

cAMP and Ca(2+)-mediated secretion in parotid acinar cells is associated with reversible changes in the organization of the cytoskeleton.

The potential involvement of actin and fodrin (brain spectrin) in secretory events has been assessed in primary cultured guinea pig parotid acinar cells, using as a tool affinity purified anti-alpha-fodrin antibody, phalloidin, and immunofluorescence techniques. In resting parotid acinar cells fodrin and actin appeared as a continuous ring under the plasma membrane of most of the cells. Upon stimulation with secretagogues fodrin and actin labeling at the level of the plasma membrane disappeared almost completely. To establish a correlation between secretion and cytoskeletal changes at the individual cell level, anti-alpha-amylase-antibodies were used to label secreted amylase exposed at the surface of secreting cells. The number of cells expressing alpha-amylase on their surface followed bulk secretion of alpha-amylase. A strict correlation between secretion and alteration of the actin-fodrin labeling was observed at the individual cell level. The cytoskeletal changes occurred in parallel with secretion independently of the secretagogue used (carbamoylcholine in the presence of Ca2+, isoproterenol in presence or absence of Ca2+, forskolin, or dibutyryl-cyclic-AMP). The changes were reversible upon removal of the secretagogue. Since Ca2+, as well as cAMP-mediated secretion, was associated with the same kind of cytoskeletal changes, a reorganization of the cytoskeleton may play an essential part in regulated secretion.

Postural variations of intraocular pressure--preflight experiments for the D1-mission.

Specific alterations in systemic circulation due to fluid shift in microgravity may lead to a rise in intraocular pressure (IOP). This situation can be simulated by head-down tilt. Several series of tonometry were performed using a handheld applanation tonometer: (1) Short time postural changes up to -90 degrees head down and back. (2) A period of 2 h in -10 degrees head down. (3) Repetition of series 2 after dehydration of the subjects. (4) Seven-day bedrest study in -7 degrees head-down tilt. (5) A period of lower body negative pressure (LBNP). (6) Valsalva maneuver. Immediately on tilting, the IOP rises with hydrostatic pressure and returns to normal again after about 1 h. The IOP seems to change parallel to venous pressure. Further experiments are planned for Spacelab missions.

Detection of simian virus 40 T-antigen-related antigens by a 125I-protein A-binding assay and by immunofluorescence microscopy on the surface of SV40-transformed monolayer cells.

Simian virus 40 (SV40)-transformed cells express the SV40-specific tumour transplantation antigen (TSTA) on the cell surface and the SV40-coded tumour antigen in their nuclei. TSTA is defined by SV40-specific transplantation immunity, whereas T-antigen (T-Ag) can be detected serologically by indirect immunofluorescence. Both antigens, however, are derived from the A gene of SV40. We therefore analysed SV40-transformed cells for the presence of serologically detectable T-Ag-related molecules. Such antigens could not be detected on the surface of living SV40-transformed cells in monolayers. However, after a short formaldehyde fixation it was possible to stain the cell surfaces of SV40-transformed cells with sera from rabbits immunized with purified SDS-denatured T-Ag, but not with sera from hamsters bearing SV40-induced tumours. T-Ag-related antigens could be detected with both types of antisera by applying a more sensitive 125I-protein A assay. The T-Ag specificity of the binding of hamster SV40 tumour sera was demonstrated be a 125I-IgG-blocking assay in which preincubation of formaldehyde-fixed SV40-transformed cells with rabbiet anti-SDS-T-Ag serum inhibited the binding of hamster SV40 tumour serum by about 70%. The localization of T-Ag-related antigens on the outside of plasma membranes of formaldehyde-fixed cells was shown by an anti-SDS-T-Ag serum-specific binding of fluorescein isothiocyanate-labelled Staphylococcus aureus to the cell surface. Out results are consistent with the hypothesis that SV40 T-Ag-related antigens are involved in the formation of TSTA.

Simian virus 40 T-antigen-related cell surface antigen: serological demonstration on simian virus 40-transformed monolayer cells in situ.

Simian virus 40 (SV40)-transformed monolayer cells were analyzed in situ by indirect immunofluorescence microscopy for the postulated cell surface location of SV40 T-antigen-related molecules. With antisera prepared against purified, sodium dodecyl sulfate-denatured SV40 T-antigen, positive surface staining was obtained when the cells had been treated with formaldehyde before immunofluorescence analysis. In contrast, living SV40-transformed cells analyzed in monolayer were surface fluorescence negative. The fixation procedure developed in this study combined with a double staining immunofluorescence technique allowed the simultaneous analysis of the same cells for the expression of both SV40 T-antigen-related surface antigen and nuclear T-antigen. The localization of SV40 T-antigen-related surface antigen on the outer surface of the plasma membrane of formaldehyde-fixed SV40-transformed cells was demonstrated directly by the protein A-mediated binding of Staphylococcus aureus bacteria on formaldehyde-fixed SV40-transformed cells precoated with antiserum against sodium dodecyl sulfate-denatured T-antigen. Both cell surface staining and S. aureus binding were found to be highly specific for SV40 T-antigen-related binding sites. These results indicate that T-antigen-related molecules in a cryptic form are located on the surface of SV40-transformed monolayer cells and can be detected in situ after modification of the cell surface architecture.