SDF-1alpha production is negatively regulated by mouse estrogen enhanced transcript in a mouse thymus epithelial cell line

Effects of Castration on miRNA, lncRNA, and mRNA Profiles in Mice Thymus

Thymic degeneration and regeneration are regulated by estrogen and androgen. Recent studies have found that long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) are involved in organ development. In this study, RNA sequencing (RNA-seq) results showed that ovariectomy significantly affected 333 lncRNAs, 51 miRNAs, and 144 mRNAs levels (p < 0.05 and |log2fold change| > 1), and orchiectomy significantly affected 165 lncRNAs, 165 miRNAs, and 208 mRNA levels in the thymus. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that differentially expressed genes (DEGs) were closely related to cell development and immunity. Next, we constructed two lncRNA–miRNA–mRNA networks using Cytoscape based on the targeting relationship between differentially expressed miRNAs (DEMs) and DEGs and differentially expressed lncRNAs (DELs) analyzed by TargetScan and miRanda. Besides, we screened DEGs that were significantly enriched in GO and in ceRNA networks to verify their expression in thymocytes and thymic epithelial cells (TECs). In addition, we analyzed the promoter sequences of DEGs, and identified 25 causal transcription factors. Finally, we constructed transcription factor-miRNA-joint target gene networks. In conclusion, this study reveals the effects of estrogen and androgen on the expression of miRNAs, lncRNAs, and mRNAs in mice thymus, providing new insights into the regulation of thymic development by gonadal hormones and non-coding RNAs.

Oestrogen, an evolutionary conserved regulator of T cell differentiation and immune tolerance in jawed vertebrates?

In teleosts, as in mammals, the immune system is tightly regulated by sexual steroid hormones, such as oestrogens. We investigated the effects of 17β-oestradiol on the expression of several genes related to T cell development and resulting T cell subpopulations in sea bass, Dicentrarchus labrax, for a primary lymphoid organ, the thymus, and two secondary lymphoid organs, the head-kidney and the spleen. In parallel, the oxidative burst capacity was assessed in leucocytes of the secondary lymphoid organs. Apoptosis- and proliferation-related genes, indicative of B and T cell clonal selection and lymphoid progenitor activity, were not affected by elevated oestrogen-levels. Sex-related oestrogen-responsiveness in T cell and antigen-presenting cell markers was observed, the expression of which was differentially induced by oestrogen-exposure in the three lymphoid organs. Remarkably, in the spleen, oestrogen increased regulatory T cell-related gene expression was associated with a decrease in oxidative burst capacity. To the best of our knowledge, this study indicates for the first time that physiological levels of oestrogen are likely to promote immune tolerance by modulating thymic function (i.e., T cell development and output) and peripheral T cells in teleosts, similar to previously reported oestrogenic effects in mammals.

Oestrogen receptor distribution related to functional thymus anatomy of the European sea bass, Dicentrarchus labrax

In jawed vertebrates, the crosstalk between immune and endocrine system as well as many fundamental mechanisms of T cell development are evolutionary conserved. Oestrogens affect mammalian thymic function and plasticity, but the mechanisms of action and the oestrogen receptors involved remain unclear. To corroborate the oestrogenic regulation of thymic function in teleosts and to identify the implicated oestrogen receptor subtypes, we examined the distribution of nuclear and membrane oestrogen receptors within the thymus of the European Sea bass, Dicentrarchus labrax, in relation to its morpho-functional organisation. Immunohistological analysis specified thymus histology and organisation in teleosts and described, for the first time, Hassall's corpuscle like structures in the medulla of sea bass. All oestrogen receptors were expressed at the transcript and protein level, both in T cells and in stromal cells belonging to specific functional areas. These observations suggest complex regulatory actions of oestrogen on thymic function, notably through the stromal microenvironment, comprising both, genomic and non-genomic pathways that are likely to affect T cell maturation and trafficking processes. Comparison with birds, rodents and humans supports the thymic localization of oestrogen receptors and suggests that oestrogens modulate T cell maturation in all gnathostomes.

Poor Mobilization in T-Cell-Deficient Nude Mice Is Explained by Defective Activation of Granulocytes and Monocytes

It has been reported that both SCID mice and SCID patients poorly mobilize hematopoietic stem/progenitor cells (HSPCs) in response to granulocyte colony-stimulating factor (G-CSF). This defect has been proposed to result from a lack of naturally occurring IgM immunoglobulins to trigger activation of the complement cascade (ComC) and release of C5 cleavage fragments crucial in the mobilization process. However, SCID individuals also have T-cell deficiency, and T cells have been shown to modulate trafficking of HSPCs. To learn more about the role of T lymphocytes, we performed mobilization studies in T-lymphocyte-deficient nude mice and found that these mice respond poorly to G-CSF and zymosan but are normal mobilizers in response to AMD3100. Since nude mice have normal levels of IgM immunoglobulins in peripheral blood and may activate the ComC, we focused on the potential involvement of Gr1+ granulocytes and monocytes, which show defective maturation in these animals. Using a nude mouse mobilization model, we found further support for the proposition that proper function of Gr1+ cells is crucial for optimal mobilization of HSPCs.

Deoxynivalenol induces apoptosis in mouse thymic epithelial cells through mitochondria-mediated pathway

Deoxynivalenol (DON) is a mycotoxin produced as a secondary metabolite by fungal species. In this report, we investigated the apoptotic effect of DON in mouse thymic epithelial cell line 1 (MTEC1). MTEC1 cell apoptosis induced by DON was confirmed by nuclei morphology change, TUNEL positive staining, annexin V/propidium iodide positive staining and increased protein levels of caspase-3, caspase-8, caspase-9 and poly(ADP-ribose) polymerase (PARP). The effects of DON on reactive oxygen species (ROS) levels and mitochondrial membrane potential were investigated via fluorescence microscope and flow cytometry, respectively. In addition, DON could significantly increase the protein levels of p53 and Bax/Bcl-2 ratio in MTEC1 cells. Taken together, our results suggest that DON causes the activation of p53, increased levels of ROS and the induction of mitochondrial dysfunction, which may contribute to DON-induced apoptosis in MTEC1 cells.

Gene expression profiling analysis of deoxynivalenol-induced inhibition of mouse thymic epithelial cell proliferation

Deoxynivalenol (DON) is a mycotoxin produced as a secondary metabolite by fungal species. It has been shown that DON has serious toxic effects on many kinds of immune cells. However, the toxic effects on thymic epithelial cells were poorly understood. The purpose of this study is to investigate the gene expression differences for the DON-induced inhibition on the proliferation of mouse thymic epithelial cell line 1 (MTEC1). After the experiments of cell viability, morphological investigation and cell cycle analysis, microarray analysis was carried out. The differentially expressed genes belong to a variety of functional categories, including genes involved in metabolic process, cell cycle, oxidation-reduction process and apoptosis. Our results provide molecular insights into the gene expression differences of DON-induced toxic effects and suggest that p53 signaling pathway may play an important role in the inhibition of MTEC1 cell proliferation.

Hormone receptor expression is associated with a unique pattern of metastatic spread and increased survival among HER2-overexpressing breast cancer patients

OBJECTIVES

HER2/neu (HER2) overexpression occurs in approximately 20% of breast cancers and is associated with aggressive disease. Although a significant number of HER2-positive tumors also express hormone receptors (HR), the effects HR expression has on clinical characteristics, including response to trastuzumab among HER2-positive breast cancer, has not been elucidated yet.

METHODS

A retrospective analysis of consecutive metastatic HER2-positive breast cancer patients was conducted in 2 medical centers. Associations between hormone receptors expression and clinical variables, and metastatic spread pattern and survival were studied.

RESULTS

The study population included 137 metastatic HER2-positive breast cancer patients, 56 of them were HR-positive and 81 were HR-negative. No significant differences between the 2 groups were found for demographic and clinical characteristics, including age, stage at diagnosis, tumor histology, and grade. Similar response rate to trastuzumab was observed in both study groups. Significantly, longer, median, disease-free, and overall survival was noted among the HR-positive patients. Patients in the HR-negative group had significantly more liver metastases, a trend for more brain metastases, and less bone metastases. There was a strong trend for more visceral metastases in the HR-negative group.

CONCLUSIONS

Our results suggest an important role for HR expression in modulating metastases predilection and disease progression in HER2-positive breast cancer.

Role of gonadal hormones in programming developmental changes in thymopoietic efficiency and sexual diergism in thymopoiesis

There is a growing body of evidence indicating the important role of the neonatal steroid milieu in programming sexually diergic changes in thymopoietic efficiency, which in rodents occur around puberty and lead to a substantial phenotypic and functional remodeling of the peripheral T-cell compartment. This in turn leads to an alteration in the susceptibility to infection and various immunologically mediated pathologies. Our laboratory has explored interdependence in the programming and development of the hypothalamo-pituitary-gonadal axis and thymus using experimental model of neonatal androgenization. We have outlined critical points in the complex process of T-cell development depending on neonatal androgen imprinting and the peripheral outcome of these changes and have pointed to underlying mechanisms. Our research has particularly contributed to an understanding of the putative role of changes in catecholamine-mediated communications in the thymopoietic alterations in adult neonatally androgenized rats.

Blockade of cysteinyl leukotriene-1 receptors suppresses airway remodelling in mice overexpressing GATA-3

BACKGROUND

We demonstrated previously that GATA-3 overexpression markedly enhanced allergen-induced airway inflammation and airway remodelling, including subepithelial fibrosis, and smooth muscle cell hyperplasia, in transgenic mice.

OBJECTIVE

Because cysteinyl leukotrienes (cysLTs) have been shown to be involved in such structural changes, the effects of a specific cysLT1 receptor antagonist, montelukast, were evaluated in a mouse model of chronic asthma.

METHODS

GATA-3-overexpressing mice and wild-type Balb/c mice were sensitized and repeatedly challenged by ovalbumin (OVA) or saline. The effects of montelukast on the development of airway remodelling were compared between the two mouse genotypes.

RESULTS

CysLTs in the lung were increased after repeated allergen challenges, and significantly enhanced in GATA-3-overexpressing mice. The enhanced cysLT levels were accompanied by the development of eosinophilia, smooth muscle cell hyperplasia, and increased stromal cell-derived factor-1 gene expression with a small increase in pro-collagen gene expression in OVA-challenged GATA-3-overexpressing mice, but not in wild-type mice. Montelukast significantly decreased lung cysLT levels and inhibited the GATA-3-overexpression-related airway remodelling, potently preventing smooth muscle cell hyperplasia, but partially suppressed the increased pro-collagen gene expression and eosinophilic inflammation. Increases in the levels of IL-4, IL-5, IL-13, and eotaxin in bronchial lavage and TGF-β gene expression in the lungs were induced by OVA in both mouse genotypes. Montelukast treatment also significantly reduced these levels to the levels seen after saline challenges in GATA-3-overexpressing mice.

CONCLUSION

Montelukast efficaciously prevented airway inflammation and remodelling in a GATA-3-overexpression antigen challenge mouse model by decreasing the cysLT-driven Th2 cytokine cycle of amplification of airway pathologies.

Basal and steroid hormone-regulated expression of CXCR4 in human endometrium and endometriosis

Endometriosis is associated with activation of local and systemic inflammatory mechanisms, including increased levels of chemokines and other proinflammatory cytokines. We have previously reported increased gene expression of chemokine receptor 4 (CXCR4), the receptor for CXCL12, in lesions of the rat model of endometriosis. The CXCR4-CXCL12 axis has been shown to have both immune (HIV infection, lymphocyte chemotaxis) and nonimmune functions, including roles in tissue repair, angiogenesis, invasion, and migration. There is evidence indicating that these mechanisms are also at play in endometriosis; therefore, we hypothesized that activation of the CXCR4-CXCL12 axis could be responsible, at least in part, for the survival and establishment of endometrial cells ectopically. Immunohistochemistry (IHC) showed that CXCR4 protein levels were significantly higher in endometriotic lesions compared to the endometrium of controls. Next, we determined basal gene and protein expression of CXCR4 and CXCL12 and regulation by estradiol (E2) and/or progesterone (P4) in endometrial cell lines using quantitative polymerase chain reaction (qPCR), and Western blots. Basal CXCR4 gene expression levels were higher in epithelial versus stromal cells; conversely, CXCL12 was expressed at higher levels in stromal vs epithelial cells. CXCR4 gene expression was significantly downregulated by ovarian steroid hormones in endometrial epithelial. These data suggest that steroid modulation of CXCR4 is defective in endometriosis, although the specific mechanism involved remains to be elucidated. These findings have implications for future therapeutic strategies specifically targeting the inflammatory component in endometriosis.

Role of the SDF-1-CXCR4 axis in stem cell-based therapies for ischemic cardiomyopathy

IMPORTANCE OF THE FIELD

Ischemic disorders are the leading cause of mortality worldwide, current therapies only delay progression of the disease. Data suggest a role of the SDF-1-CXCR4 axis in attenuation of ischemic disorders.

AREAS COVERED IN THIS REVIEW

We discuss the importance of SDF-1-CXCR4 interactions during development and postnatal mobilization and migration of stem cells. We focus on the role of the SDF-1-CXCR4 axis in stem-cell-based applications for attenuation of ischemic cardiomyopathy.

WHAT THE READER WILL GAIN

During development the SDF-1-CXCR4 axis plays a critical role in gradient-guided cell movements. In adults, the SDF-1-CXCR4 axis is involved in retention and mobilization of stem cells. Since SDF-1 is upregulated during hypoxic tissue damage, strategies to augment or stabilize SDF-1 have been utilized to target blood-derived stem cells to ischemic tissue. We exploited this concept by preventing SDF-1 degradation with dipeptidylpeptidaseIV (DPPIV) inhibition and mobilization of stem cells by G-CSF after acute myocardial infarction. This targeted CD34(+)CXCR4(+) cells to ischemic heart and attenuated ischemic cardiomyopathy.

TAKE HOME MESSAGE

The SDF-1-CXCR4 axis plays a role in stem cell homing during embryogenesis and adulthood especially after ischemia. Preserving functional SDF-1 by DPPIV inhibition after ischemia may enhance stem cell therapies.

Nerve growth factor stimulates proliferation, adhesion and thymopoietic cytokine expression in mouse thymic epithelial cells in vitro

Thymic epithelial cells, which constitute a major component of the thymic microenvironment, provide a crucial signal for intrathymic T cell development and selection. Neuroimmune networks in the thymic microenvironment are thought to be involved in the regulation of T cell development. NGF is increasingly recognized as a potent immunomodulator, promoting "cross-talk" between various types of immune system cells. The present study clearly shows that NGF stimulates mouse thymic epithelial cell activities in vitro including cell proliferation, thymocyte adhesion to thymic epithelial cells, and the expression of cell adhesion molecules such as ICAM-1 and VCAM-1, and thymopoietic factors including IL-7, GM-CSF, SDF-1, TARC and TECK. Thus, our data are of considerable clinical importance showing that trophic NGF activity could be used to enhance the thymus regeneration and develop methods to improve host immunity when the immune function is depressed due to thymic involution.

Migration of mouse antibody-secreting hybridoma cells from blood to genital tract and its regulation by sex hormones are associated with the differential expression patterns of adhesion molecules and chemokines in the tract rather than in the antibody-secreting cells

To understand better the molecular mechanisms of differential migration of antibody-secreting cells (ASCs) into mouse genital tracts, and regulation by sex hormones, surface markers, hormone receptors and adhesion molecules in mouse SG2 and PA4 hybridoma cells, respectively, secreting IgG2b and polymeric IgA antibody were detected by flow cytometry or RT-PCR. Semi-quantitative RT-PCR was also used for measuring mRNA expression of adhesion molecules and chemokines (VCAM-1, ICAM-1, P-selectin, JAM-1 and CXCL12) in genital tracts of various adult mouse groups. The mRNAs of androgen receptor, estrogen receptor beta and CXCR4 were expressed in the ASCs. Sex hormones had no effect on expression of these molecules in ASCs. Except for VCAM-1, mRNA of all examined genes was expressed in normal mouse genital tracts. The mean of relative amounts of ICAM-1 and CXCL12 mRNA in all examined organs of females were higher (2.1- and 1.9-fold) than those in males. After orchiectomy or ovariectomy, the expression of ICAM-1, CXCL12 and P-selectin mRNA in the examined organs increased, except JAM-1 in male and CXCL12 in female. Sex hormone treatment recovered the changes to normal levels of mRNA expression in many examined genital tissues. In combination with our previous work, preferential migration of ASCs into female genital tract and regulation of migration by sex hormones are associated with expression patterns of adhesion molecules and chemokines in genital tract rather than in ASCs.

The pleiotropic effects of the SDF-1–CXCR4 axis in organogenesis, regeneration and tumorigenesis

Proper response of normal stem cells (NSC) to motomorphogens and chemoattractants plays a pivotal role in organ development and renewal/regeneration of damaged tissues. Similar chemoattractants may also regulate metastasis of cancer stem cells (CSC). Growing experimental evidence indicates that both NSC and CSC express G-protein-coupled seven-transmembrane span receptor CXCR4 and respond to its specific ligand alpha-chemokine stromal derived factor-1 (SDF-1), which is expressed by stroma cells from different tissues. In addition, a population of very small embryonic-like (VSEL) stem cells that express CXCR4 and respond robustly to an SDF-1 gradient was recently identified in adult tissues. VSELs express several markers of embryonic and primordial germ cells. It is proposed that these cells are deposited early in the development as a dormant pool of embryonic/pluripotent NSC. Expression of both CXCR4 and SDF-1 is upregulated in response to tissue hypoxia and damage signal attracting circulating NSC and CSC. Thus, pharmacological modulation of the SDF-1-CXCR4 axis may lead to the development of new therapeutic strategies to enhance mobilization of CXCR4+ NSC and their homing to damaged organs as well as inhibition of the metastasis of CXCR4+ cancer cells.

Regulation of stromal cell-derived factor-1 and exhaled nitric oxide in asthmatic children following montelukast and ketotifen treatment

BACKGROUND

Montelukast and ketotifen are oral anti-allergy medications in asthmatic children. This study investigates the modulation effect of montelukast and ketotifen on children with intermittent to mild persistent asthma as demonstrated by the levels of peak expiratory flow (PEF), asthma scores (AS), exhaled nitric oxide (eNO) and plasma stromal cell-derived factor-1 (SDF-1) concentration in a randomized, prospective study.

METHODS

Fifty asthmatic children were enrolled and received 8 weeks of treatment with oral montelukast sodium 5mg chewable tablet administered once daily, or 1mg ketotifen, and were followed for a 4-week post-treatment washout period. ENO concentration, AS and PEF were measured before, 2, 4, 6 and 8 weeks after initial treatment, and 4 weeks after cessation of treatment.

RESULTS

Montelukast therapy was showed to improve AS, PEF and eNO within 2 weeks and remained the improvement during the treatment period. Montelukast also significantly decreased plasma SDF-1 levels after 8 weeks of treatment. In contrast, the ketotifen treatment revealed no significant effects in these clinical parameters until 4 and 6 weeks of the therapy, and did not suppress plasma SDF-1 levels after 8 weeks of treatment. To prove whether montelukast directly suppressed SDF-1 induction, we studied effects of montelukast on the LPS-induced SDF-1 expression and SDF-1-induced chemotaxis of monocytic (THP-1) cells. Montelukast, but not ketotifen, could suppress SDF-1 expression and its related chemotaxis on THP-1 monocytic cells.

CONCLUSIONS

Leukotriene receptor antagonist, such as montelukast, may be a better non-steroid anti-inflammatory drug for mild childhood asthma in preventing airway inflammation.

Trafficking of normal stem cells and metastasis of cancer stem cells involve similar mechanisms: pivotal role of the SDF-1-CXCR4 axis

The alpha-chemokine stromal-derived factor (SDF)-1 and the G-protein-coupled seven-span transmembrane receptor CXCR4 axis regulates the trafficking of various cell types. In this review, we present the concept that the SDF-1-CXCR4 axis is a master regulator of trafficking of both normal and cancer stem cells. Supporting this is growing evidence that SDF-1 plays a pivotal role in the regulation of trafficking of normal hematopoietic stem cells (HSCs) and their homing/retention in bone marrow. Moreover, functional CXCR4 is also expressed on nonhematopoietic tissue-committed stem/progenitor cells (TCSCs); hence, the SDF-1-CXCR4 axis emerges as a pivotal regulator of trafficking of various types of stem cells in the body. Furthermore, because most if not all malignancies originate in the stem/progenitor cell compartment, cancer stem cells also express CXCR4 on their surface and, as a result, the SDF-1-CXCR4 axis is also involved in directing their trafficking/metastasis to organs that highly express SDF-1 (e.g., lymph nodes, lungs, liver, and bones). Hence, we postulate that the metastasis of cancer stem cells and trafficking of normal stem cells involve similar mechanisms, and we discuss here the common molecular mechanisms involved in these processes. Finally, the responsiveness of CXCR4+ normal and malignant stem cells to an SDF-1 gradient may be regulated positively/primed by several small molecules related to inflammation which enhance incorporation of CXCR4 into membrane lipid rafts, or may be inhibited/blocked by small CXCR4 antagonist peptides. Consequently, strategies aimed at modulating the SDF-1-CXCR4 axis could have important clinical applications both in regenerative medicine to deliver normal stem cells to the tissues/organs and in clinical hematology/oncology to inhibit metastasis of cancer stem cells.