Tracy Niven-Fairchild

The Fas/Fas‐ligand system: a mechanism for immune evasion in human breast carcinomas

Breast tumors are frequently associated with a predominantly lymphocytic infiltrate, which constitutes an immune response against the tumor. In spite of this massive infiltrate, the immune response appears to be inefficient and the tumor is able to evade it. We propose that in breast cancer, tumor escape from immunological surveillance results from the induction of apoptosis of Fas‐bearing activated lymphocytes by FasL‐bearing breast cancer cells.To test this proposal we studied the expression of FasL by human breast carcinomas and the MCF‐7 breast cancer cell line by RT‐PCR, immunohistochemistry, and Western Blot. Moreover, we describe the presence of apoptosis and Fas expression in the lymphocytic population surrounding the tumor. Strong membranous and cytoplasmic staining was detected in ductal carcinomas and hyperplastic breast tissue, but it was absent from normal breast tissue. No staining was found in normal glands in the non‐tumor quadrant; however, the normal appearing ducts surrounding the carcinoma (tumor quadrant) showed intense immunoreactivity. Apoptosis was found predominantly among the lymphocytic population, as well as in the blood vessels and fibro‐fatty tissue close to the tumor. Further characterization of apoptotic cells demonstrated that they were CD3+ cells.Our results suggest the breast tumors may elude immunological surveillance by inducing, via the Fas‐FasL system, the apoptosis of activated lymphocytes. Recent data have demonstrated FasL RNA in other tumor types. Upregulation of FasL expression in hyperplastic and normal breast ducts close to the tumor also suggests a possible role in early neoplastic transformation and proliferation.Abbreviations: Con A: concanavalin A; FasL: Fas ligand; RT-PCR: reverse transcription+polymerase chain reaction.

Polarized distribution of Na+,K+-ATPase in giant cells elicited in vivo and in vitro.

Giant cell formation was analyzed to determine whether it results in the high level of Na+,K+-ATPase expression that characterizes multinucleated cells such as osteoclasts. Giant cells and fusing alveolar macrophages were subjected to morphological, immunological, and biochemical studies. Both subunits of the Na+,K+-ATPase were found to be present on the plasma membrane of giant cells. Their localization was restricted to the non-adherent domain of the cell surface. Dynamic studies of giant cell differentiation demonstrated that on culture and/or multinucleation, an increase in sodium pump alpha-subunit synthesis occurred and led to a high level of expression of Na pumps. Conversely, the adherent plasma membrane of giant cells was enriched in a lysosomal membrane antigen. This study demonstrates that culture and/or multinucleation induces a significant increase in the expression of sodium pumps. The polarized distribution of these pumps and of a lysosomal component suggests that fusing macrophages undergo biochemical and morphological alterations which prepare them for a new and specialized function in chronic inflammatory reactions. Giant cells may offer a suitable model system to study the differentiation of other related multinucleated cells, such as osteoclasts.

Glucocorticoids Enhance CD163 Expression in Placental Hofbauer Cells

Periplacental levels of glucocorticoid (GC) peak at parturition, and synthetic GC is administered to women at risk for preterm delivery. However, little is known concerning cell-type-specific effects of GC in placenta. Hofbauer cells (HBCs) are fetal macrophages that are located adjacent to fetal capillaries in placenta. The goal of the current study was to determine whether GC treatment altered HBC gene expression and function. Western blotting and flow cytometry revealed CD163 and folate receptor-β (FR-β), markers of antiinflammatory M2 macrophages, were specifically expressed by primary cultures of HBCs immunopurified from human term placentas. GC receptor mRNA and protein levels were higher in HBCs compared with placental fibroblasts. Treatment of HBCs with cortisol or dexamethasone (DEX) markedly and specifically enhanced CD163 protein and mRNA levels, whereas expression of FR-β and CD68 were largely unresponsive to GC treatment. DEX treatment also increased hemoglobin uptake by HBCs, evidence of enhanced HBC function. The level of CD163 mRNA, but not FR-β or CD68 mRNA, was stimulated in placental explant cultures by DEX treatment, and increased CD163/FR-β and CD163/CD68 mRNA ratios sensitively reflected the response to GC. Maternal GC administration was associated with increased CD163/FR-β and CD163/CD68 mRNA ratios in placentas from women with spontaneous preterm birth. In conclusion, in vitro studies indicated that GC treatment specifically up-regulated CD163 expression in HBCs and enhanced HBC function. In addition, the observed alterations in patterns of expression of macrophage marker genes associated with maternal GC administration suggest that HBCs are in vivo targets of GC action.

Focal increases of fetal macrophages in placentas from pregnancies with histological chorioamnionitis: potential role of fibroblast monocyte chemotactic protein-1.

Citation Toti P, Arcuri F, Tang Z, Schatz F, Zambrano E, Mor G, Niven‐Fairchild T, Abrahams VM, Krikun G, Lockwood CJ, Guller S. Focal increases of fetal macrophages in placentas from pregnancies with histological chorioamnionitis: potential role of fibroblast monocyte chemotactic protein‐1. Am J Reprod Immunol 2011; 65: 470–479

Outcome following femur fracture and subsequent cecal ligation and puncture in endotoxin-sensitive (C3H/HeN) and endotoxin-resistant (C3H/HeJ) mice☆

This study examined the effect of sepsis following trauma in a reproducible model of sepsis--cecal ligation and puncture (CLP)--in endotoxin-sensitive (C3H/HeN) and endotoxin-resistant (CeH/HeJ) mice. Studies used CLP with a 25-gauge needle at different time intervals following injury, as induced by femur fracture (FF), to determine the effects of sublethal sepsis on survival after trauma. There was a 3% mortality for FF alone in both groups. Mortality in C3H/HeJ mice was not significantly increased over FF alone except when CLP followed FF by 3 days (45%, P less than 0.02, Chi-square). In contrast, C3H/HeN mice had significantly increased mortality rates (75 to 90%, P less than 0.001) versus FF alone at all intervals between FF and CLP. Mortality for FF plus CLP was significantly greater for C3H/HeN compared to C3H/HeJ (P less than 0.001) for all time intervals between FF and CLP. In conclusion, animals exposed to a septic episode following FF had significantly greater mortality than FF animals without a septic challenge. Endotoxin-sensitive mice had significantly higher mortality after CLP and significantly increased mortality when CLP followed FF (regardless of timing) compared to endotoxin-resistant mice.

Toll-like Receptor-Mediated Responses by Placental Hofbauer Cells (HBCs): A Potential Pro-Inflammatory Role for Fetal M2 Macrophages

Microbial‐driven responses in placenta are linked with adverse pregnancy outcomes. The role of Toll‐like receptor (TLR) function in Hofbauer cells (HBCs) and fetal macrophages of the placental villous core remains understudied.

Decreased levels of folate receptor-β and reduced numbers of fetal macrophages (Hofbauer cells) in placentas from pregnancies with severe pre-eclampsia.

Pre‐eclampsia (PE), a pregnancy complication of unknown etiology, is a major cause of maternal and fetal mortality and morbidity. Previous studies have described placental genes that are up‐regulated in expression in PE, but few studies have addressed placental gene suppression in this syndrome.

Microinjection of mitochondria into zygotes creates a model for studying the inheritance of mitochondrial DNA during preimplantation development

OBJECTIVE To determine the effect of mutant mitochondria on preimplantation embryo development and of preimplantation embryo development on the survival of mutant mitochondrial DNA. DESIGN Laboratory research. SETTING Academic research laboratory. PATIENT(S) None. INTERVENTION(S) Mutant and wild-type mitochondria, fractionated from tissue obtained from a patient with MELAS syndrome, a mitochondrial disease, were microinjected into mouse zygotes. Control zygotes received either no injection or sham injection. MAIN OUTCOME MEASURE(S) Preimplantation embryo development and survival of mutant mitochondrial DNA as determined by polymerase chain reaction analysis. RESULT(S) After microinjection into zygotes, the MELAS mutation could be identified by polymerase chain reaction until the hatched blastocyst stage of embryo development. The survival of MELAS-injected zygotes, observed for 4 days after injection, did not differ from the survival of zygotes injected with wild-type mitochondria or from the survival of uninjected or sham-injected controls. CONCLUSION(S) It appears that preimplantation embryo development does not screen out mitochondrial DNA mutations introduced into fertilized oocytes, and low levels of mutant mitochondrial DNA do not disrupt early embryo development.