Purification and characterization of glutathione S-transferases of rat uterus

Characterization of the uterine phenotype during the peri-implantation period for LIF-null, MF1 strain mice

Leukemia inhibitory factor plays a major role in the uterus and in its absence embryos fail to implant. Our knowledge of the targets for LIF and the consequences of its absence is still very incomplete. In this study, we have examined the ultrastructure of the potential implantation site in LIF-null MF1 female mice compared to that of wild type animals. We also compared expression of proteins associated with implantation in luminal epithelium and stroma. Luminal epithelial cells (LE) of null animals failed to develop apical pinopods, had increased glycocalyx, and retained a columnar shape during the peri-implantation period. Stromal cells of LIF-null animals showed no evidence of decidual giant cell formation even by day 6 of pregnancy. A number of proteins normally expressed in decidualizing stroma did not increase in abundance in the LIF-null animals including desmin, tenascin, Cox-2, bone morphogenetic protein (BMP)-2 and -7, and Hoxa-10. In wild type animals, the IL-6 family member Oncostatin M (OSM) was found to be transiently expressed in the luminal epithelium on late day 4 and then in the stroma at the attachment site on days 5-6 of pregnancy, with a similar but not identical pattern to that of Cox-2. In the LIF-null animals, no OSM protein was detected in either LE or stroma adjacent to the embryo, indicating that expression requires uterine LIF in addition to a blastocyst signal. Fucosylated epitopes: the H-type-1 antigen and those recognized by lectins from Ulex europaeus-1 and Tetragonolobus purpureus were enhanced on apical LE on day 4 of pregnancy. H-type-1 antigen remained higher on day 5, and was not reduced even by day 6 in contrast to wild type uterus. These data point to a profound disturbance of normal luminal epithelial and stromal differentiation during early pregnancy in LIF-nulls. On this background, we also obtained less than a Mendelian ratio of null offspring suggesting developmental failure.

Marked expression of glutathione S-transferase A4-4 detoxifying 4-hydroxy-2(E)-nonenal in the skin of rats irradiated by ultraviolet B-band light (UVB)

Enzyme, Western blot, and immunohistochemical analyses indicated that rat skin cytosol contained no detectable level of the homodimeric, alpha-class glutathione S-transferase (rGST) A4-4 which catalyzes the GSH conjugation of the toxic product, 4-hydroxy-2(E)-nonenal (HNE), nonenzymatically formed from n-6 polyunsaturated fatty acid residues of lipids by lipid peroxidation. Rats irradiated by single doses (4000-24,000 mJ/cm(2)) of ultraviolet B-band light (UVB, 200 mJ/cm(2)/min) markedly expressed rGSTA4-4 in the skin at a level one-fifth that of the liver in apparent specific activity toward HNE at a single dose of 24,000 mJ/cm(2). Skin rGSTA4-4 was isolated, purified to homogeneity, and identified with hepatic rGSTA4-4 by reverse-phase partition HPLC and by amino acid sequence analysis of its CNBr fission peptides. Immunohistochemistry with polyclonal antibody raised against rGSTA4-4 demonstrated the selective expression of rGSTA4-4 in epidermis and sebaceous glands localized in dermis after UVB irradiation.

Glutathione S-transferases of rabbit lung macrophages

The catalytic activities of glutathione S-transferases (GSTs), particularly the alpha-class isozymes, can provide protection against oxidative stress through GSH-mediated metabolism of reactive products of lipid peroxidation. Lipid peroxidation products from oxidative metabolism in alveolar macrophages play an important role in mediating and regulating inflammatory response and injury in the lung. The rabbit has been used as an important animal model for studies of the role of alveolar macrophages in pulmonary pathology. Although rabbit lung macrophages display GST activity, the isozyme-specific expression of GSTs and the catalytic properties of these isozymes has not previously been defined. In present studies, we have purified the GST isozymes of rabbit alveolar macrophages obtained by bronchoalveolar lavage and performed immunologic and kinetic characterization of the purified isozymes. Results of our studies indicate the presence of three alpha-class isozymes (pI 10.2, 9.3, and 6.0) and one micro-class isozyme (pI 7.2). N-terminal sequence analysis of the micro-class isozyme indicated that it was distinct from the two previously described micro-class isozymes of rabbit. Kinetic studies indicated that two cationic alpha-class GSTs (pI 10.2 and 9.3) contribute the large majority of selenium independent GSH-peroxidase activity toward dilinoleoyl phosphatidylcholine hydroperoxide (kcat/Km values of 83.4 and 31.9 s-1 . M-1 . 10(3), respectively). A third alpha-class GST (pI 6.0) was shown to have highest catalytic activity toward conjugation of the 4-hydroxynonenal (4HNE) with GSH (kcat/Km = 1900 s-1 . M-1 . 10(3)). Structural and immunologic characterization of this GST isozyme indicated that it belongs to a subclass of the alpha-classGSTs selectively expressed in mesodermal origin cells that are exposed to high levels of oxidative stress and are characterized by high specific activity toward both lipid hydroperoxides and 4-HNE.

Rat GST 8-8 is expressed predominantly in myeloid origin cells infiltrating the gravid uterus

Previous studies from our laboratory have shown a relatively high expression of rGST8-8 in uterine tissues. This GST isozyme displays relatively high glutathione-peroxidase activity towards lipid-hydroperoxides and towards toxic 4-hydroxyalkenals generated from lipid peroxidation. Since the uterus is a unique organ, subject to oxidative stress due to infiltration by immune effector cells during gestation and because this infiltration is readily identifiable histologically, the studies reported herein were performed to localize the cell specific expression of rGST8-8 to determine whether immune effector cells infiltrating the pregnant rat uterus specifically expressed rGST8-8. A 75 bp end-radiolabeled cRNA probe was prepared from the full length mGSTA4-4 cDNA from the region which is highly homologous with rGST8-8. This cRNA probe was used for in situ hybridization studies to localize rGST8-8 in specific cell types of gravid rat uterus. Results of these studies indicate that this GST isozyme is selectively expressed in myeloid origin cells such as monocytes/macrophages, and neutrophils infiltrating the uterine endometrium and in vascular walls. Selective expression of rGST8-8 in the myeloid origin cells, which are known to generate higher levels of reactive oxygen species, suggests that this GST isozyme plays an important role in the protection mechanisms against lipid peroxidation.