Human Chorionic Gonadotropin Improves the Proliferation and Regenerative Potential of Bone Marrow Adherent Stem Cells and the Immune Tolerance of Fetal Microchimeric Stem Cells In Vitro

The when, what, and where of naturally-acquired microchimerism

Naturally acquired microchimerism (Mc) is increasingly recognized as an aspect of normal biology. Maternal-fetal bi-directional exchange during pregnancy creates a Mc legacy for the long-term in both individuals. Maternal Mc in her offspring and Mc of fetal origin in women with previous births are best studied. Other sources include from a known or vanished twin, miscarriage or pregnancy termination, older sibling, or previous maternal pregnancy loss. Mc is pleotropic and protean, present in diverse forms, and changing over time as other aspects of biology. Mc acquired from multiple sources, at different lifespan times, and taking on an array of diverse forms, creates a "forward, reverse, and horizontal inheritance" Mc landscape. Mc is found in adaptive and innate immune cells, as resident tissue-specific cells in a wide variety of human tissues, and among other forms as extracellular vesicles. HLA molecules function in a myriad of ways as key determinants for health and are of central importance in interactions between genetically disparate individuals. Studies of autoimmune disease have firmly established a primary role of HLA molecules. Studies of iatrogenic chimerism have established benefit of donor-recipient HLA-disparity against recurrent malignancy after transplantation. HLA molecules and HLA-relationships of families are therefore of particular interest in seeking to understand the role(s) of Mc at the interface of auto-immunity and healthy allo-immunity. This review will begin by providing perspective on Mc in biology followed by a primary focus on persistent Mc according to the human lifespan, in healthy individuals and with illustrative examples of autoimmune diseases.

Effects of Replicative Senescence of Human Chorionic MSCs on their EV-miRNA Profile

Chorionic mesenchymal stromal cells (CHO-MSCs) and their extracellular vesicles (EVs) are becoming increasingly popular, since chorion is ethically harmless and an easily accessible source of MSCs. However, until now there is only a limited number of studies with a thorough characterization of CHO-MSCs derived EVs and their miRNA profile. In this study, we monitored changes in the EV-miRNA profile between early and late passage of human CHO-MSCs. First, senescence of CHO-MSCs was induced by serial passaging and confirmed by morphological changes, shortened telomeres and changes in the expression of selected genes. The expression of MSCs-specific surface markers CD73, CD90, CD105 did not change with increasing passages. Next, EVs and their miRNA profiles were compared between early vs late passage cells. Number of EVs and their size were not significantly changed. Seven of the top 10 most expressed EV-miRNAs were common to both early and late passages. A differential expression study between early and late passages identified 37 significantly differentially expressed EV-miRNAs, out of which 23 were found to be associated with pathways of cellular senescence based on KEGG pathway analysis. A set of 9 miRNAs were identified as the most frequently associated with senescence and/or with the most altered expression between early and late passages, out of which miR-145-5p, miR-335-5p and miR-199b-3p were the most significant downregulated miRNAs in late passages. The most upregulated EV-miRNAs were miR-1307-3p, miR-3615 and miR320b. Targeting these miRNAs in future experiments may prolong the therapeutic potential of CHO-MSCs and their EVs.

Widespread Distribution of Luteinizing Hormone/Choriogonadotropin Receptor in Human Juvenile Angiofibroma: Implications for a Sex-Specific Nasal Tumor

Juvenile angiofibroma (JA) is a rare, sex-specific, and highly vascularized nasal tumor that almost exclusively affects male adolescents, but its etiology has been controversial. The G protein-coupled hormone receptor LHCGR [luteinizing hormone (LH)/choriogonadotropin (hCG) receptor] represents a promising new candidate for elucidating the underlying mechanisms of sex specificity, pubertal manifestation, and JA progression. We used highly sensitive RNAscope technology, together with immunohistochemistry, to investigate the cellular expression, localization, and distribution of LHCGR in tissue samples from JA patients. Our results provide evidence for LHCGR expression in subsets of cells throughout JA tissue sections, with the majority of LHCGR+ cells located in close vicinity to blood vessels, rendering them susceptible to endocrine LH/hCG signaling, but LHCGR+ cells were also detected in fibrocollagenous stroma. A majority of LHCGR+ cells located near the vascular lumen co-expressed the neural crest stem cell marker CD271. These results are intriguing as both LH and hCG are produced in a time- and sex-dependent manner, and are known to be capable of inducing cell proliferation and angiogenesis. Our results give rise to a new model that suggests endocrine mechanisms involving LHCGR and its ligands, together with autocrine and paracrine signaling, in JA vascularization and cell proliferation.

Synergistic Effect of Human Chorionic Gonadotropin and Granulocyte Colony Stimulating Factor in the Mobilization of HSPCs Improves Overall Survival After PBSCT in a Preclinical Murine Model. Are We Far Enough for Therapy?

Strategies to improve hematopoietic stem and progenitor cell (HSPC) mobilization from the bone marrow can have a pivotal role in addressing iatrogenic bone-marrow insufficiency from chemo(radio)therapy and overcoming peripheral blood stem cell transplantation (PBSCT) limitations such as insufficient mobilization. Granulocyte-colony stimulating factor (G-CSF) represents the standard mobilization strategy for HSPC and has done so for more than three decades since its FDA approval. Its association with non-G-CSF agents is often employed for difficult HSPC mobilization. However, obtaining a synergistic effect between the two classes is limited by different timing and mechanisms of action. Based on our previous in vitro results, we tested the mobilization potential of human chorionic gonadotropin (HCG), alone and in combination with G-CSF in vivo in a murine study. Our results show an improved mobilization capability of the combination, which seems to act synergistically in stimulating hematopoiesis. With the current understanding of the dynamics of HSPCs and their origins in more primitive cells related to the germline, new strategies to employ the mobilization of hematopoietic progenitors using chorionic gonadotropins could soon become clinical practice.

Fetal microchimerism and the two-stage model of preeclampsia

Fetal cells cross the placenta during pregnancy and some have the ability to persist in maternal organs and circulation long-term, a phenomenon termed fetal microchimerism. These cells often belong to stem cell or immune cell lineages. The long-term effects of fetal microchimerism are likely mixed, potentially depending on the amount of fetal cells transferred, fetal-maternal histocompatibility and fetal cell-specific properties. Both human and animal data indicate that fetal-origin cells partake in tissue repair and may benefit maternal health overall. On the other hand, these cells have been implicated in inflammatory diseases by studies showing increased fetal microchimerism in women with autoimmune diseases such as systemic lupus erythematosus and rheumatoid arthritis. During pregnancy, preeclampsia is associated with increased cell-transfer between the mother and fetus, and an increase in immune cell subsets. In the current review, we discuss potential mechanisms of transplacental transfer, including passive leakage across the compromised diffusion barrier and active recruitment of cells residing in the placenta or fetal circulation. Within the conceptual framework of the two-stage model of preeclampsia, where syncytiotrophoblast stress is a common pathophysiological pathway to maternal and fetal clinical features of preeclampsia, we argue that microchimerism may represent a mechanistic link between stage 1 placental dysfunction and stage 2 maternal cardiovascular inflammation and endothelial dysfunction. Finally, we postulate that fetal microchimerism may contribute to the known association between placental syndromes and increased long-term maternal cardiovascular disease risk. Fetal microchimerism research represents an exciting opportunity for developing new disease biomarkers and targeted prophylaxis against maternal diseases.

Stem Cells in the Tumor Immune Microenvironment -Part of the Cure or Part of the Disease? Ontogeny and Dichotomy of Stem and Immune Cells has Led to better Understanding

Stem cells are at the basis of tissue homeostasis, hematopoiesis and various regenerative processes. Epigenetic changes in their somatically imprinted genes, prolonged exposure to mutagens/carcinogens or alteration of their niche can lead to the development of an enabling environment for tumor growth and progression. The involvement of stem cells in both health and disease becomes even more compelling with ontogeny as embryonic and extraembryonic stem cells which persist into adulthood in well established and specific niche may have distinct implications in tumorigenesis. Immune surveillance plays an important role in this interplay since the response of immune cells toward the oncogenic process can range from reactivity to placidity and even complicity, being orchestrated by intercellular molecular dialogues with the other key players of the tumor microenvironment. With the current understanding that every developing and adult tissue contains inherent stem and progenitor cells, in this manuscript we review the most relevant interactions carried out between the stem cells, tumor cells and immune cells in a bottom-up incursion through the tumor microenvironment beginning from the perivascular niche and going through the tumoral parenchyma and the related stroma. With the exploitation of various factors that influence the behavior of immune effectors toward stem cells and other resting cells in their niche, new therapeutic strategies to tackle the polarization of immune effectors toward a more immunogenic phenotype may arise.