Stress reticulocytes lose transferrin receptors by an extrinsic process involving spleen and macrophages.

As they mature into erythrocytes during normal erythropoiesis, reticulocytes lose surface transferrin receptors before or concurrently with reticulin. Exosome release accounts for most of the loss of transferrin receptors from reticulocytes. During erythropoietic stress, reticulocytes are released early from hematopoietic tissues and have increased reticulin staining and transferrin receptors. Flow cytometry of dually stained erythrocytes of mice recovering from phlebotomy demonstrated delayed loss of reticulin and transferrin receptors during in vitro maturation compared to in vivo maturation, indicating that an in vivo process extrinsic to the reticulocytes facilitates their maturation. Splenectomy or macrophage depletion by liposomal clodronate inhibited in vivo maturation of reticulocytes and increased the numbers of reticulin-negative, transferrin receptor-positive cells during and after recovery from phlebotomy. This reticulin-negative, transferrin receptor-positive population was rarely found in normal mice. Transmission electron microscopy demonstrated that the reticulin-negative, transferrin receptor-positive cells were elongated and discoid erythrocytes, but they had intracellular and surface structures that appeared to be partially degraded organelles. The results indicate that maturation of circulating stress reticulocytes is enhanced by an extrinsic process that occurs in the spleen and involves macrophage activity. Complete loss of reticulin with incomplete loss of surface transferrin receptors in this process produces a reticulin-negative, transferrin receptor-positive erythrocyte population that has potential utility for detecting prior erythropoietic stresses including bleeding, hemolysis and erythropoietin administration, even after recovery has been completed. Am. J. Hematol. 91:875-882, 2016. © 2016 Wiley Periodicals, Inc.

Preclinical studies with JAA-F11 anti-Thomsen-Friedenreich monoclonal antibody for human breast cancer.

AIM: The Thomsen-Friedenreich antigen (TF-Ag) is a disaccharide hidden on normal cells, but selectively exposed on the surface of breast, colon, prostate and bladder cancer cells. JAA-F11, a highly specific monoclonal antibody to TF-Ag, reduces metastasis and prolongs survival in a mouse model. In addition,(124)I-JAA-F11 localizes 4T1 tumors in mice. These studies continue translation of JAA-F11 to human breast cancer. MATERIALS & METHODS & RESULTS: Of the 41 human breast cancer cell lines tested, 78% were positive for reactivity with JAA-F11 by whole-cell enzyme immunoassay and positivity occurred unrelated to estrogen, progesterone or HER2 receptor status. JAA-F11 inhibited the growth rate of the human cancer cell lines tested. At 1 h, approximately 80% of JAA-F11 internalized in the three cell lines tested. (124)I-JAA-F11 specifically imaged human triple-negative tumors in mice by microPET. CONCLUSION: The results highlight the potential that humanized JAA-F11 may have for immunotherapy and drug conjugate therapy in breast cancer patients.

Direct effects of conjugated linoleic acid isomers on P815 mast cells in vitro.

Conjugated linoleic acid (CLA) is a dietary fatty acid which causes extensive remodeling and mast cell recruitment in the mouse mammary gland. Two CLA isomers, 9,11- and 10,12-CLA, have differing effects in vivo, with only 10,12-CLA increasing mast cell number. The purpose of this project is to test the hypothesis that CLA acts directly on the mast cell. The P815 mastocytoma cell line was assayed for the effects of CLA on mast cell number, proliferation, apoptosis, and differentiation. Both CLA isomers decreased viable mast cell number, with no effect on membrane integrity, or cell cycle distribution. 10,12-CLA induced an increase in apoptosis, assessed by Annexin-FITC binding. Both isomers increased mast cell granularity, and secretion of MMP-9. The complex effects of CLA isomers on mast cells in the mammary gland are distinct from direct effects on mast cells in vitro, and may require interactions between multiple cell types present in vivo.

Gene Annotation in High Schools: Successful Student Pipeline and Teacher Professional Development in Bioscience Using GENI-ACT.

Knowledge of genomics is an essential component of science for high school student health literacy. However, few high school teachers have received genomics training or any guidance on how to teach the subject to their students. This project explored the impact of a genomics and bioinformatics research pipeline for high school teachers and students using an introduction to genome annotation research as the catalyst. The Western New York-based project had three major components: (1) a summer teacher professional development workshop to introduce genome annotation research, (2) teacher-guided student genome annotation group projects during the school year, (3) with an end of the academic year capstone symposium to showcase student work in a poster session. Both teachers and students performed manual gene annotations using an online annotation toolkit known as Genomics Education National Initiative-Annotation Collaboration Toolkit (GENI-ACT), originally developed for use in a college undergraduate teaching environment. During the school year, students were asked to evaluate the data they had collected, formulate a hypothesis about the correctness of the computer pipeline annotation, and present the data to support their conclusions in poster form at the symposium. Evaluation of the project documented increased content knowledge in basic genomics and bioinformatics as well as increased confidence in using tools and the scientific process using GENI-ACT, thus demonstrating that high school students are capable of using the same tools as scientists to conduct a real-world research task.

Tumor immunolocalization using 124 I-iodine-labeled JAA-F11 antibody to Thomsen-Friedenreich alpha-linked antigen.

Clinical immunolocalization has been attempted by others with an anti-Thomsen-Friedenreich antigen (TF-Ag) mAb that bound both alpha- and beta-linked TF-Ag. In this report, 124 I-labeled mAb JAA-F11 specific for alpha-linked TF-Ag showed higher tumor specificity in in vivo micro-positron emission tomography (micro-PET) of the mouse mammary adenocarcinoma line, 4T1, showing no preferential uptake by the kidney. Labeled product remained localized in the tumor for at least 20 days. Glycan array analysis showed structural specificity of the antibody.

Humanization of JAA-F11, a Highly Specific Anti-Thomsen-Friedenreich Pancarcinoma Antibody and InVitro Efficacy Analysis.

JAA-F11 is a highly specific mouse monoclonal to the Thomsen-Friedenreich Antigen (TF-Ag) which is an alpha-O-linked disaccharide antigen on the surface of ~80% of human carcinomas, including breast, lung, colon, bladder, ovarian, and prostate cancers, and is cryptic on normal cells. JAA-F11 has potential, when humanized, for cancer immunotherapy for multiple cancer types. Humanization of JAA-F11, was performed utilizing complementarity determining regions grafting on a homology framework. The objective herein is to test the specificity, affinity and biology efficacy of the humanized JAA-F11 (hJAA-F11). Using a 609 target glycan array, 2 hJAA-F11 constructs were shown to have excellent chemical specificity, binding only to TF-Ag alpha-linked structures and not to TF-Ag beta-linked structures. The relative affinity of these hJAA-F11 constructs for TF-Ag was improved over the mouse antibody, while T20 scoring predicted low clinical immunogenicity. The hJAA-F11 constructs produced antibody-dependent cellular cytotoxicity in breast and lung tumor lines shown to express TF-Ag by flow cytometry. Internalization of hJAA-F11 into cancer cells was also shown using a surface binding ELISA and confirmed by immunofluorescence microscopy. Both the naked hJAA-F11 and a maytansine-conjugated antibody (hJAA-F11-DM1) suppressed in vivo tumor progression in a human breast cancer xenograft model in SCID mice. Together, our results support the conclusion that the humanized antibody to the TF-Ag has potential as an adjunct therapy, either directly or as part of an antibody drug conjugate, to treat breast cancer, including triple negative breast cancer which currently has no targeted therapy, as well as lung cancer.

The effect of proteasome inhibitors on mammalian erythroid terminal differentiation.

OBJECTIVES: Murine erythroblasts infected with the anemia-inducing strain of Friend virus (FVA cells) terminally differentiate to the reticulocyte stage after 48 hours of culture in vitro in response to erythropoietin (EPO). The objective of this study was to determine the possible role of proteasome-mediated proteolysis during the terminal differentiation of FVA cells. MATERIALS AND METHODS: The proteasome inhibitors MG132 and lactacystin were used to perturb the normal function of proteasomes during terminal differentiation. Effects of proteasome inhibitors on terminal differentiation were quantitated by evaluation of cellular morphology after benzidine staining and by Western blot analyses. RESULTS: Treatment of EPO-stimulated FVA cells with lactacystin or MG132 at later periods of culture increased accumulations of nuclear and cytosolic ubiquitinated proteins and decreased nuclear extrusion to less than 40% of controls. CONCLUSIONS: Our results suggest that the proteasomal degradation of ubiquitinated proteins plays an important role in the enucleation of mammalian erythroblasts.

Folate exacerbates the effects of ethanol on peripubertal mouse mammary gland development.

Alcohol consumption is linked with increased breast cancer risk in women, even at low levels of ingestion. The proposed mechanisms whereby ethanol exerts its effects include decreased folate levels resulting in diminished DNA synthesis and repair, and/or acetaldehyde-generated DNA damage. Based on these proposed mechanisms, we hypothesized that ethanol would have increased deleterious effects during periods of rapid mammary gland epithelial proliferation, such as peripuberty, and that folate deficiency alone might mimic and/or exacerbate the effects of ethanol. To test this hypothesis, weight-matched 28-35 day old CD2F1 female mice were pair-fed liquid diets ±3.2% ethanol, ±0.1% folate for 4 weeks. Folate status was confirmed by assay of liver and kidney tissues. In folate deficient mice, no significant ethanol-induced changes to the mammary gland were observed. Folate replete mice fed ethanol had an increased number of ducts per section, due to an increased number of terminal short branches. Serum estrogen levels were increased by ethanol, but only in folate replete mice. These results demonstrate that folate deficiency alone does not mimic the effects of ethanol, and that folate deficiency in the presence of ethanol blocks proliferative effects of ethanol on the mammary ductal tree.

Accuracy and biological variation of human serum paraoxonase 1 activity and polymorphism (Q192R) by kinetic enzyme assay.

BACKGROUND: Paraoxonase 1 (PON1) phenotype is a better predictor of atherosclerosis risk than are PON1 genetic polymorphisms alone. Larger studies are required to determine the role of PON1 and there is a need for standardized PON1 assays between laboratories. METHODS: We have adapted 5 enzyme kinetic assays for high-throughput automated analysis of PON1 activity. Using different substrates and reaction conditions, we measured PON1 activity and used activity ratios to identify the PON1 Q192R genetic polymorphisms and assessed the accuracy of the genotype assignments in 79 adult study participants by comparing them with genotypes determined by AlwI restriction enzyme digestion of a 176-bp PCR amplification product from genomic DNA. Imprecision was determined using pooled serum and purified enzyme preparations. Biological variability was estimated by analysis of serial samples from 17 individuals. Variability parameters were compared with total cholesterol as a point of reference to a recognized biomarker of coronary heart disease risk. RESULTS: Salt stimulation and inhibition ratios were 97.4% and 94.7% correct in assigning Q192R genotype, respectively. Analytical imprecision (CV) was 1.0%-3.0% for phenylacetate and paraoxon substrate assays and 3.0%-8.0% for the para-nitrophenylacetate substrate assays. Combination of the 2 ratios into a double ratio resulted in 100% correct genotype classification. CONCLUSION: The described methods for measurement of PON1 activity and accurate genotype assignment are rapid and have potential to facilitate the efficient investigation of PON1 status in clinical and epidemiological studies.

In vitro maturation of nascent reticulocytes to erythrocytes.

Most studies of mammalian reticulocyte maturation have used blood reticulocytes. Nascent reticulocytes, as found in bone marrow, have not been available in developmentally synchronized populations. Nascent murine reticulocytes formed in vitro by enucleation of Friend virus-infected erythroblasts were purified and recultured for 110 hours. At 0 hours, all recultured cells were lobulated and contained dense, centralized reticulin. By 110 hours, about 20% to 25% of the cells became biconcave erythrocytes. Most ribosomes and cellular RNAs were degraded within 20 hours, and during that period, heme synthesis declined from a rate equal to that of late erythroblasts to less than 10% of that rate. Many mitochondria appeared normal until they showed outer membrane swelling, degradation, and apparent fusion with intracellular vacuoles at 40 hours of culture. During the period of mitochondrial loss, Bcl-X(L), an antiapoptotic protein that accumulates during erythroblast differentiation and maintains mitochondrial membrane integrity, demonstrated progressive decreases and changes consistent with deamidation. Nevertheless, the reticulocytes did not undergo apoptosis, because their apoptotic machinery was degraded. This experimental system that provides a developmentally synchronized population of nascent murine reticulocytes that mature into biconcave erythrocytes in vitro should be useful in further investigations of the cellular events involved in reticulocyte maturation.

Localization and early time course of TGF-beta 1 mRNA expression in dystrophic muscle.

Fibrosis is a common pathological feature observed in muscle from patients with Duchenne muscular dystrophy (DMD). In the dystrophic (mdx) mouse model of DMD, the diaphragm is more severely affected than other skeletal muscles. The level of transforming growth factor-beta1 (TGF-beta1), an inflammatory cytokine, is significantly elevated in mdx diaphragm. However, little is known about the onset of TGF-beta1 messenger ribonucleic acid (mRNA) expression, or which cells express the mRNA. In this study, we characterized the location and time course of expression of TGF-beta1 mRNA in diaphragm from mdx mice. TGF-beta1 mRNA was significantly elevated in mdx diaphragm at 6 and 9 but not 12 weeks of age, and these changes corresponded with changes in type I collagen mRNA and hydroxyproline concentration. Mononucleated cells localized to areas of fiber necrosis highly expressed the TGF-beta1 transcript in mdx diaphragm. Neutralization of TGF-beta1 by decorin administration resulted in a 40% reduction in the level of diaphragm muscle type I collagen mRNA. These findings support a role for TGF-beta1 during the early stages of fibrogenesis in dystrophic diaphragm muscle. Therapeutic interventions aimed at neutralizing this cytokine may be beneficial in slowing the development of fibrosis in DMD.