Localized SCF and IGF-1 secretion enhances erythropoiesis in the spleen of murine embryos

Insulin-like growth factor system components expressed at the conceptus-maternal interface during the establishment of equine pregnancy

In many species, the insulin-like growth factors (IGF1 and IGF2), their receptors and IGF binding proteins play important roles in preparing the endometrium for implantation, and regulating conceptus growth and development. To determine whether the IGF system may contribute to conceptus-maternal interaction during equine pre-implantation development, we evaluated mRNA expression for IGF system components in conceptuses, and endometrium recovered from pregnant and cycling mares, on days 7, 14, 21 and 28 after ovulation. We also investigated expression of IGF1, IGF2 and their receptors 6 and 11 days after transfer of day 8 embryos to synchronous (day 8) or asynchronous (day 3) recipient mares. Expression of IGF1 and IGF2, IGF1R, IGF2R, INSR and IGFBPs 1, 2, 4 and 5 was evident in endometrium and conceptus membranes during days 7–28. Endometrial IGF2, INSR, IGFBP1 and IGFBP2 expression increased between days 7 and 28 of pregnancy. In conceptus membranes, expression of all IGF system components increased with developmental stage. Immunohistochemistry revealed strong expression of IGF1, IGF2 and IGF1R in both endometrium and conceptus membranes, whereas INSR was highly expressed in endometrium but barely detectable in the conceptus. Finally, a negatively asynchronous uterine environment retarded IGF1, IGF2 and INSR expression in the conceptus, whereas in the endometrium only INSR expression was altered by asynchrony. The presence of IGFs, their receptors and IGFBPs in the endometrium and conceptus during early equine pregnancy, and down-regulation in the conceptus following asynchronous embryo transfer, suggest a role in conceptus-maternal communication during the preparation for implantation.

Existence of multiple organ aging in animal model of emphysema induced by cigarette smoke extract

INTRODUCTION

It is commonly considered that COPD or at least emphysema represents accelerated lung aging induced in part by oxidative damage from cigarette smoke components. However, the issue if there are any aging signs in other organs in patients with COPD or emphysema remains unclear. The aim of this study is to explore whether there is multiple organ aging in the animal model of emphysema induced by cigarette smoke extract (CSE), and to ascertain the possible mechanisms, if any.

METHODS

The animal model of emphysema was induced by CSE. Histomorphological changes in lung, heart, liver, kidney and spleen tissues were measured after staining with hematoxylin and eosin (H&E). The concentrations of stem cell factor (SCF), CyclinD1 and superoxide dismutase (SOD) in serum were determined by ELISA kit. The expressions of p16 (INK4a), Sca-1, eNOS proteins and mRNA in lung, heart, liver, kidney and spleen tissues were detected by Western blotting and quantitative reverse transcriptase polymerase chain reaction (qRT-PCR), respectively. Decitabine (Dec) was applied to examine whether it could alter the changes caused by CSE.

RESULTS

The histomorphology of lung tissue was significantly changed, while other organs exhibited normal structure and histomorphology. The concentrations of SCF, CyclinD1 and SOD in serum were lower in the CSE group than in the control group. The expression levels of p16(INK4a) protein and mRNA in lung, heart, liver, kidney and spleen tissues were higher in the CSE group than in the control group, while the expression levels of Sca-1 and eNOS proteins and mRNA were lower in the CSE group than in the control group, in the tissues described above. Dec could partly alleviate the damages caused by CSE and the degree of alleviation resulted by Dec varied from organ to organ.

CONCLUSIONS

In addition to the aging of the lung tissue in the emphysema animal model induced by CSE, the tissues of the heart, liver, kidney and spleen were also in the progress of aging, but the sensibility and affinity of lung to CSE were higher than those of the other organs. Multiple organ aging may also exist in the animal model of emphysema induced by CSE. DEC can partly alleviate the multiple organ aging caused by CSE.

Tissue distribution of stem cell factor in adults

Stem cell factor (SCF) is an essential cytokine during development and is necessary for gametogenesis, hematopoiesis, mast cell development, stem cell function, and melanogenesis. Here, we measure SCF concentration and distribution in adult humans and mice using gene expression analysis, tissue staining, and organ protein lysates. We demonstrate continued SCF expression in many cell types and tissues into adulthood. Tissues with high expression in adult humans included stomach, spleen, kidney, lung, and pancreas. In mice, we found high SCF expression in the esophagus, ovary, uterus, kidney, and small intestine. Future studies may correlate our findings of increased, organ-specific SCF concentrations within adult tissues with increased risk of SCF/CD117-related disease.

Fibroblasts as confederates of the immune system

Fibroblastic stromal cells are as diverse, in origin and function, as the niches they fashion in the mammalian body. This cellular variety impacts the spectrum of responses elicited by the immune system. Fibroblast influence on the immune system keeps evolving our perspective on fibroblast roles and functions beyond just a passive structural part of organs. This review discusses the foundations of fibroblastic stromal-immune crosstalk, under the scope of stromal heterogeneity as a basis for tissue-specific tutoring of the immune system. Focusing on the skin as a relevant immunological organ, we detail the complex interactions between distinct fibroblast populations and immune cells that occur during homeostasis, injury repair, scarring, and disease. We further review the relevance of fibroblastic stromal cell heterogeneity and how this heterogeneity is central to regulate the immune system from its inception during embryonic development into adulthood.

Stimulation of Gastric Transit Function Driven by Hydrolyzed Casein Increases Small Intestinal Carbohydrate Availability and Its Microbial Metabolism

Gastrointestinal (GI) functions affect gut nutrient flow and microbial metabolism. Dietary peptides modulate GI functions and improve small intestinal health, but the mechanism remains elusive. This study aims to investigate whether dietary peptides affect small intestinal microbial metabolism, and the underlying mechanisms. An ileal-cannulated pig model is adopted to explore the relationship between gut nutrient flow and microbial metabolism after treatment with hydrolyzed casein (peptides) or intact casein (Control)-based diet. The results demonstrate that hydrolyzed casein enhances microbial carbohydrate metabolism with higher Streptococcus abundance and higher lactate level in the ileum. Meanwhile, hydrolyzed casein increases ileal flows of nutrients, especially carbohydrate, leading to a higher carbohydrate availability in ileal digesta. To unveil the mechanisms, it is found that the hydrolyzed casein enhances the ghrelin signal and improves development of interstitial cells of Cajal and muscular layer in gastric corpus, indicating the enhanced upper GI transit function. In addition, hydrolyzed casein improves small intestinal health, as indicated by higher villus heights and luminal lactate concentrations in the jejunum and ileum. In conclusion, hydrolyzed casein stimulates upper GI transit function, enhances gut nutrient flow, and increases small intestinal carbohydrate availability and its microbial metabolism, which favor the small intestinal health.

Paracrine CCL17 and CCL22 signaling regulates hematopoietic stem/progenitor cell migration and retention in mouse fetal liver

Fetal liver (FL) is the major embryonic hematopoietic organ and a site where circulating hematopoietic stem/progenitor cells (HSPCs) reside. However, HSPC migration/retention mechanisms in FL remain unclear. A chemokine screen revealed that the CCR4 ligands CCL17 and CCL22 are highly expressed in mouse embryonic day (E) 12.5 FL. Flow cytometric analysis confirmed CCR4 expression in FL HSPCs. To identify sources of CCL17 and CCL22, we fractionated FL into various cell types and found that Ccl17 and Ccl22 were predominantly expressed in HPCs/matured HCs. In vitro cell migration analysis confirmed enhanced HSPC migration in the presence of HPCs/matured HCs. Furthermore, exo-utero injection of anti-CCR4 neutralizing antibody into pregnant mice significantly reduced the number of FL HSPCs in embryos. These data demonstrate a paracrine mechanism by which HSPC migration/retention is regulated by CCL17 and CCL22 secreted from HPCs or matured HCs in FL.

The Emerging Role of the RBM20 and PTBP1 Ribonucleoproteins in Heart Development and Cardiovascular Diseases

Alternative splicing is a regulatory mechanism essential for cell differentiation and tissue organization. More than 90% of human genes are regulated by alternative splicing events, which participate in cell fate determination. The general mechanisms of splicing events are well known, whereas only recently have deep-sequencing, high throughput analyses and animal models provided novel information on the network of functionally coordinated, tissue-specific, alternatively spliced exons. Heart development and cardiac tissue differentiation require thoroughly regulated splicing events. The ribonucleoprotein RBM20 is a key regulator of the alternative splicing events required for functional and structural heart properties, such as the expression of TTN isoforms. Recently, the polypyrimidine tract-binding protein PTBP1 has been demonstrated to participate with RBM20 in regulating splicing events. In this review, we summarize the updated knowledge relative to RBM20 and PTBP1 structure and molecular function; their role in alternative splicing mechanisms involved in the heart development and function; RBM20 mutations associated with idiopathic dilated cardiovascular disease (DCM); and the consequences of RBM20-altered expression or dysfunction. Furthermore, we discuss the possible application of targeting RBM20 in new approaches in heart therapies.

Analysis of Hematopoietic Niche in the Mouse Embryo

The development, differentiation, and maturation of hematopoietic cells are regulated by the intrinsic and extrinsic regulation. Intrinsic activity is affected by cell autonomous gene expression and extrinsic factors originate from the so-called niche surrounding the hematopoietic cells. It remains unclear why the hematopoietic sites are shifted during embryogenesis. Flow cytometry and immunohistochemistry enable us to study embryonic regulation of hematopoietic niche in the mouse embryo.

Regulation of the embryonic erythropoietic niche: a future perspective

The production of red blood cells, termed erythropoiesis, occurs in two waves in the developing mouse embryo: first primitive erythropoiesis followed by definitive erythropoiesis. In the mouse embryo, both primitive and definitive erythropoiesis originates in the extra-embryonic yolk sac. The definitive wave then migrates to the fetal liver, fetal spleen and fetal bone marrow as these organs form. The fetal liver serves as the major organ for hematopoietic cell expansion and erythroid maturation after mid-gestation. The erythropoietic niche, which expresses critical cytokines such as stem cell factor (SCF), thrombopoietin (TPO) and the insulin-like growth factors IGF1 and IGF2, supports hematopoietic expansion in the fetal liver. Previously, our group demonstrated that DLK1⁺ hepatoblasts support fetal liver hematopoiesis through erythropoietin and SCF release as well as extracellular matrix deposition. Loss of DLK1⁺ hepatoblasts in Map2k4^−/− mouse embryos resulted in decreased numbers of hematopoietic cells in fetal liver. Genes encoding proteinases and peptidases were found to be highly expressed in DLK1⁺ hepatoblasts. Capitalizing on this knowledge, and working on the assumption that these proteinases and peptidases are generating small, potentially biologically active peptides, we assessed a range of peptides for their ability to support erythropoiesis in vitro. We identified KS-13 (PCT/JP2010/067011) as an erythropoietic peptide-a peptide which enhances the production of red blood cells from progenitor cells. Here, we discuss the elements regulating embryonic erythropoiesis with special attention to niche cells, and demonstrate how this knowledge can be applied in the identification of niche-derived peptides with potential therapeutic capability.

Fanconi Anemia and Laron Syndrome

BACKGROUND

Fanconi anemia (FA) is a condition characterized by genetic instability and short stature, which is due to growth hormone (GH) deficiency in most cases. However, no apparent relationships have been identified between FA complementation group genes and GH. In this study, we thereby considered an association between FA and Laron syndrome (LS) (insulin-like growth factor 1 [IGF-1] deficiency).

METHODS

A 21-year-old female Mexican patient with a genetic diagnosis of FA was referred to our research department for an evaluation of her short stature. Upon admission to our facility, her phenotype led to a suspicion of LS; accordingly, serum levels of IGF-1 and IGF binding protein 3 were analyzed and a GH stimulation test was performed. In addition, we used a next-generation sequencing approach for a molecular evaluation of FA disease-causing mutations and genes involved in the GH-IGF signaling pathway.

RESULTS

Tests revealed low levels of IGF-1 and IGF binding protein 3 that remained within normal ranges, as well as a lack of response to GH stimulation. Sequencing confirmed a defect in the GH receptor signaling pathway.

CONCLUSIONS

To the best of our knowledge, this study is the first to suggest an association between FA and LS. We propose that IGF-1 administration might improve some FA complications and functions based upon IGF-1 beneficial actions observed in animal, cell and indirect clinical models: erythropoiesis modulation, immune function improvement and metabolic regulation.

Effects of maternal exposure to di-n-butyl phthalate during pregnancy and breastfeeding on ovarian development and function of F1 female rats

This study aimed to investigate the effects of maternal exposure to di-n-butyl phthalate (DBP) during pregnancy and breastfeeding on F1 ovarian development and function. A rat model of maternal exposure to DBP during pregnancy and breastfeeding was established by gavage feeding female Sprague Dawley rats with 0, 10, 100, or 600mg/kg/day DBP from gestational day (GD) 12 to postnatal day (PND) 21. F1 offspring were weaned on PND21 and were not exposed to DBP afterward. The age of vaginal opening and estrus onset, estrous cyclicity, c-Kit-ligand expression on ovarian granulosa cells, and the weight of ovaries and uterus of F1 female offspring were not affected, whereas serum levels of estradiol and progesterone were increased significantly by maternal exposure to 10mg/kg/day DBP from GD12 to PND21. Although F1 ovarian function may not be adversely affected by maternal exposure to DBP, the increased reproductive hormone levels may interfere in F1 rat fertility.