Robust engraftment of fetal nonhuman primate CD34-positive cells in immune-deficient mice

Nonhuman primates (NHPs) represent one of the most important models for preclinical studies of novel biomedical interventions. In contrast with small animal models, however, widespread utilization of NHPs is restricted by cost, logistics, and availability. Therefore, we sought to develop a translational primatized mouse model, akin to a humanized mouse, to allow for high-throughput in vivo experimentation leveraged to inform large animal immunology-based studies. We found that adult rhesus macaque mobilized blood (AMb) CD34+-enriched hematopoietic stem and progenitor cells (HSPCs) engrafted at low but persistent levels in immune-deficient mice harboring transgenes for human (NHP cross-reactive) GM-CSF and IL3, but did not in mice with wild-type murine cytokines lacking NHP cross-reactivity. To enhance engraftment, fetal liver-derived HSPCs were selected as the infusion product based on an increased CD34hi fraction compared with AMb and bone marrow. Coupled with cotransplantation of rhesus fetal thymic fragments beneath the mouse kidney capsule, fetal liver-derived HSPC infusion in cytokine-transgenic mice yielded robust multilineage lymphohematopoietic engraftment. The emergent immune system recapitulated that of the fetal monkey, with similar relative frequencies of lymphocyte, granulocyte, and monocyte subsets within the thymic, secondary lymphoid, and peripheral compartments. Importantly, while exhibiting a predominantly naïve phenotype, in vitro functional assays demonstrated robust cellular activation in response to nonspecific and allogenic stimuli. This primatized mouse represents a viable and translatable model for the study of hematopoietic stem cell physiology, immune development, and functional immunology in NHPs. Summary Sentence: Engraftment of rhesus macaque hematopoietic tissues in immune-deficient mice yields a robust BLT/NeoThy-type primatized mouse model for studying nonhuman primate hematopoiesis and immune function in vivo.

Metabolic gene profile in early human fetal heart development

The primitive cardiac tube starts beating 6-8 weeks post fertilization in the developing embryo. In order to describe normal cardiac development during late first and early second trimester in human fetuses this study used microarray and pathways analysis and created a corresponding 'normal' database. Fourteen fetal hearts from human fetuses between 10 and 18 weeks of gestational age (GA) were prospectively collected at the time of elective termination of pregnancy. RNA from recovered tissues was used for transcriptome analysis with Affymetrix 1.0 ST microarray chip. From the amassed data we investigated differences in cardiac development within the 10-18 GA period dividing the sample by GA in three groups: 10-12 (H1), 13-15 (H2) and 16-18 (H3) weeks. A fold change of 2 or above adjusted for a false discovery rate of 5% was used as initial cutoff to determine differential gene expression for individual genes. Test for enrichment to identify functional groups was carried out using the Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG). Array analysis correctly identified the cardiac specific genes, and transcripts reported to be differentially expressed were confirmed by qRT-PCR. Single transcript and Ontology analysis showed first trimester heart expression of myosin-related genes to be up-regulated >5-fold compared with second trimester heart. In contrast the second trimester hearts showed further gestation-related increases in many genes involved in energy production and cardiac remodeling. In conclusion, fetal heart development during the first trimester was dominated by heart-specific genes coding for myocardial development and differentiation. During the second trimester, transcripts related to energy generation and cardiomyocyte communication for contractile coordination/proliferation were more dominant. Transcripts related to fatty acid metabolism can be seen as early as 10 weeks and clearly increase as the heart matures. Retinol receptor and gamma-aminobutyric acid (GABA) receptor transcripts were detected, and have not been described previously in human fetal heart during this period. For the first time global gene expression of heart has been described in human samples to create a database of normal development to understand and compare with known abnormal fetal heart development.

Differential changes in gene expression in human brain during late first trimester and early second trimester of pregnancy

OBJECTIVE

This study aimed to describe brain development during the first (B1) and second trimester (B3) in human fetuses.

DESIGN

Ten brains from 10 to 18 weeks of gestational age (GA) were collected, and the RNA was used for transcriptome analysis (Affymetrix 1.0 ST microarray chip). Differences in brain development within 10 to 18 GA were investigated by dividing the sample into 10 to 12 (B1), 13 to 15(B2) and 16 to 18(B3) weeks. A fold change of 2 or above, with a false discovery rate of 5%, was used as cut-off to determine differential gene expression for individual genes. Quantitative real-time PCR was used to confirm differences. Tests for enrichment procedures (using Gene Ontology and Kyoto Encyclopedia of Genes and Genomes) were then used to identify functional groups of mRNA.

RESULTS

At 10 to 12 weeks, brains showed neuronal migration to be upregulated. From 10 to 18 weeks, brains showed genes coding for neuronal migration, differentiation and connectivity upregulated. ALDH1A1 and NPY genes, marker of spinal cord and striatum, were upregulated in B1 and B3 brains, respectively. Also, SLITRK6-HAS2 and CRYAB-PCDH18 genes for ear and eye sensory input were upregulated in B1.

CONCLUSIONS

For the first time, brain global gene expression was described in human samples. Period B1 was dominated by genes coding for neuronal migration, differentiation, programmed cell death and sensory organs. B3 was dominated by neuronal proliferation, branching and myelination. Creating such a database will allow comparison with abnormals in future studies.

IFPA Meeting 2011 workshop report III: Placental immunology; epigenetic and microRNA-dependent gene regulation; comparative placentation; trophoblast differentiation; stem cells

Workshops are an important part of the IFPA annual meeting as they allow for discussion of specialised topics. At IFPA meeting 2011 there were twelve themed workshops, five of which are summarized in this report. These workshops related to various aspects of placental biology: 1) immunology; 2) epigenetics; 3) comparative placentation; 4) trophoblast differentiation; 5) stem cells.

Uterine and ovarian aryl hydrocarbon receptor (AHR) and aryl hydrocarbon receptor nuclear translocator (ARNT) mRNA expression in benign and malignant gynaecological conditions

The transcriptional regulators aryl hydrocarbon receptor (AHR) and aryl hydrocarbon receptor nuclear translocator (ARNT) modulate the transcription of genes involved in cellular differentiation and proliferation. In this study, we investigated the expression of these transcriptional regulators in the female reproductive tract. AHR and ARNT mRNA transcripts were readily detected by a ribonuclease protection assay in all reproductive tissues examined. The expression of these factors in the endometrium and myometrium did not vary during the menstrual cycle, and was not different in pre- versus post-menopausal women. However, post-menopausal women on continuous hormone replacement therapy had greater expression of AHR but not of ARNT in the endometrium and myometrium when compared with women not taking hormones. Leiomyomas expressed significantly less AHR and ARNT mRNA compared with normal myometrium. The ovaries expressed both AHR and ARNT mRNA, and expression was unaffected by age. Endometriotic ovarian cysts expressed more AHR but not more ARNT mRNA compared with healthy ovarian tissue. However, there were no changes in the expression of AHR or ARNT mRNA in ovarian cancer. In conclusion, the female reproductive tract expresses mRNA for the transcription factors AHR and ARNT, and changes in their expression at select target sites in specific pathological conditions such as endometriosis and uterine leiomyomas suggest a potential role for these factors in the pathogenesis of these conditions.

The influence of aging and sex hormones on expression of growth hormone-releasing hormone in the human immune system

GHRH is a neuropeptide that has also been localized to the immune system. The physiological function of GHRH in the immune system has not been elucidated. This study was conducted to determine whether immune GHRH expression is altered in certain pathological states, such as immune cell tumors, and whether gender, aging, and alterations in the sex steroid milieu influence the expression of this peptide in immune cells. Using double color flow cytometry, GHRH protein was found to be expressed in less than 2% of peripheral blood mononuclear cells (PBMC). Monocytes and B and T cells all expressed GHRH protein, although a greater percentage of T cells compared with B cells and monocytes expressed GHRH (5- to 7-fold). Semiquantitative RT-PCR was used to quantify GHRH messenger ribonucleic acid (mRNA) in PBMC and several immune cell-derived tumors. PBMC and granulocytes expressed low levels of GHRH mRNA with relatively higher levels of expression in monocytes. The tumor cell lines CEMX 174 (B/T cells), HUT 78 (T cells), WIL2-N (B cells), U937 (monocytes/macrophages), and JM 1 (pre-B cell lymphoma) all showed greater expression of GHRH mRNA relative to PBMC. However, two cell lines, CCRF-SB, a B lymphoblastoid cell line, and HL-60, a promyelocytic cell line, expressed GHRH mRNA at similar levels as PBMC. A significant decrease in the percentage of lymphocytes (CD45(+) cells) expressing GHRH protein was found in age-advanced men and women compared with young men and women. This decline was noted in B cells (CD20(+)) and monocytes (CD14(+)), but not in T cells (CD3(+)). GHRH mRNA expression in PBMC derived from postmenopausal women was lower than that from premenopausal women. However, no differences in PBMC GHRH mRNA expression were found in young and old men. Although in older men there were fewer peripheral lymphocytes that express GHRH protein, these cells secreted significantly more GHRH in vitro than cells from postmenopausal women with no hormone replacement therapy (HRT), but similar levels as cells from women receiving HRT. PBMC from women receiving HRT secreted more GHRH in vitro than cells from women receiving no hormone replacement. This study demonstrates that the expression of immune GHRH is dynamic, and therefore likely to be regulated. Increased expression of GHRH in certain immune tumors suggests that GHRH may be mitogenic under certain conditions and therefore play a role in the pathogenesis of select immune cell tumors. Collectively, these results suggest a role for GHRH as a local immune modulator and in the pathophysiology of immunosenescence and immune cell tumors.

Human uterine and ovarian expression of growth hormone-releasing hormone messenger RNA in benign and malignant gynecologic conditions

OBJECTIVE

To determine uterine and ovarian expression of growth hormone-releasing hormone (GHRH) messenger RNA (mRNA) in benign and pathologic gynecologic states.

DESIGN

Case-control study.

SETTING

Tertiary-care academic department.

PATIENT(S)

Women undergoing hysterectomy for benign or malignant gynecologic conditions.

INTERVENTION(S)

Ovarian and uterine tissue was obtained for measurement of GHRH mRNA levels by reverse transcription polymerase chain reaction.

MAIN OUTCOME MEASURE(S)

Levels of GHRH mRNA in normal tissues were compared with those in tissues with pathologic abnormalities.

RESULT(S)

Growth hormone-releasing hormone mRNA was detectable in the ovary, endometrium, myometrium, fallopian tubes, and placenta. Levels of GHRH mRNA were significantly increased in secretory endometrium compared with proliferative endometrium. Hormone replacement therapy did not affect endometrial GHRH mRNA levels. Uterine myomas expressed similar levels of GHRH mRNA as normal myometrium. No changes in endometrial GHRH mRNA were detected in endometrial cancers compared with normal endometrium or myometrium obtained from the same patient; however, these levels were higher than those in noncancerous myometrial tissue obtained from other patients with benign gynecologic disease. In ovarian tissue, no differences in GHRH mRNA were found between premenopausal and postmenopausal women. Ovarian GHRH mRNA was significantly decreased in endometriotic cysts, whereas significantly greater GHRH expression occurred in ovarian cancer compared with normal ovarian tissue.

CONCLUSION(S)

Endometrial and ovarian GHRH gene transcription are altered in selective physiologic and pathologic states and are influenced by such factors as ovarian hormones. Because it is a growth factor, GHRH may promote endometrial proliferation and may be involved in the pathogenesis of ovarian and endometrial cancer and endometriosis.