Biochemical and Biophysical Research Communications
Maternal exosomes in diabetes contribute to the cardiac development deficiency
Introduction
The high incidence of congenital heart defects (CHD) has become a worldwide health problem, although the incidence in different studies varies from about 4/1000 to 50/1000 in live births [1]. Moreover, maternal pregestational diabetes mellitus induces a 4–10 fold increase in offspring CHD risk [2], [3]. Illustration of the underlying mechanisms would shed light on the prevention and therapy. Previous studies have demonstrated that hyperglycemia during early embryogenesis would alter gene expression in key cellular components of the developing heart [4], such as Notch, Pitx2, Wnt, NKX2.5 and GATA4 genes signal-dependent expression. In addition, embryos exposed to high concentrations of glucose suffer from high levels of cellular oxidative stress [5], which perturb intracellular metabolic homeostasis, and ultimately affect the cell survival, proliferation and differentiation, resulting in embryo myocardial apoptosis and fibrosis [6]. However, role of other factors besides hyperglycemia involved in the initiation of CHD remains largely unknown.
Exosomes are nanovesicles (40–100 nm in diameter) and have been confirmed as one of the pivotal mediators of cell-cell communication among neighboring or distant cells [7], [8]. Exosomes play a key role in multiple physiological or pathological processes, such as tumor metastasis and dissemination of pathogen-as well as host-derived molecules during infection [7], [9]. Exosomes have intact and functional mRNAs, miRNAs, and proteins. Recent evidences suggest miRNAs act as “fine tuners” and/or “safeguards” to maintain the homeostasis of cardiovascular system and a central role in embryonic cardiogenesis (e.g., miR-1 and mir-133-a/b) [10], [11]. It has been revealed that specific stimuli of high glucose and cellular stress could alter the plasma exosome amount and components [9]. Notably, the observation that exosomes can cross the blood brain barrier indicates [12] that exosomes might directly move from maternal to fetal tissues, and vice-versa, during pregnancy [13]. Taken together, we assume that exosomes in the diabetic pregnancy would affects the CHD.
In this study, we analyzed the exosomal miRNAs in the diabetic maternal mice via RNA-seq, and confirmed their capacity to cross the maternal-fetal barrier. Moreover, we found that injection of the exosomes from diabetic pregnant mice increased the CHD risk. All of these results confirmed an important role of aberrant exosomes from the maternal diabetes in cardiac development deficiency, providing novel insight on CHD prevention and therapy.
Section snippets
Diabetic mice induction and mice mating
Diabetic pregnant mouse model was yielded as described before [14], and all the procedures for animal experiment were approved by the Fourth Military Medical University Institutional Animal Care and Use Committee. Briefly, eight-week-old female C57BL/6J mice were purchased from the Animal center of the Fourth Military Medical University. Mice were maintained in a room with 12-h light-dark cycle and the temperature kept between 24 °C and 26 °C. After arrival, mice were divided into 2 groups and
Diabetes mellitus increases the incidence of embryonic cardiac development defect
Diabetic pregnant mice model was established as shown in Fig. 1A. Compared with the control group, STZ treatment in the pregnant mice induced a low fertility rate and a high rate of stillbirth and subsequent absorption, as seen from the gross observation of the pregnant uterus (Fig. 1B). Moreover, there were an increasing number of malformation in the survived fetal mice in the STZ group, such as acrania and anophthalmia (Fig. 1C). To further examine the effects of pregnant diabetes on the
Discussion
To our knowledge, this is the first study revealing that exosomes from pregnant diabetic mouse, specifically exosomal miRNAs, are involved in the embryonic development deficiency. By combinatory application of labeled exosomes and nano-scaled gold particles, we confirmed that the exosomes could cross the maternal-fetal barrier. Moreover, we showed that the exosomes from diabetic mouse, which displayed significant changes of miRNAs, induced a systemic and significant development deficiency.
Acknowledgements
This study was funded by NSFC 81671690, 81170149 and 81370275 to Yuan LJ, and International Collaboration Project, Tangdu Hospital (No. 2015GJHZ001). We are grateful to Xiangjie Chen (Department of Mathematics, Southeast University, Nanjing 211189, China) for his professional assistance in statistical analysis.
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