The angiogenic properties of human amniotic membrane stem cells are enhanced in gestational diabetes and associate with fetal adiposity

Background

An environment of gestational diabetes mellitus (GDM) can modify the phenotype of stem cell populations differentially according to their placental localization, which can be useful to study the consequences for the fetus. We sought to explore the effect of intrauterine GDM exposure on the angiogenic properties of human amniotic membrane stem cells (hAMSCs).

Methods

We comprehensively characterized the angiogenic phenotype of hAMSCs isolated from 14 patients with GDM and 14 controls with normal glucose tolerance (NGT). Maternal and fetal parameters were also recorded. Hyperglycemia, hyperinsulinemia and palmitic acid were used to in vitro mimic a GDM-like pathology. Pharmacological and genetic inhibition of protein function was used to investigate the molecular pathways underlying the angiogenic properties of hAMSCs isolated from women with GDM.

Results

Capillary tube formation assays revealed that GDM-hAMSCs produced a significantly higher number of nodes (P = 0.004), junctions (P = 0.002) and meshes (P < 0.001) than equivalent NGT-hAMSCs, concomitant with an increase in the gene/protein expression of FGFR2, TGFBR1, SERPINE1 and VEGFA. These latter changes were recapitulated in NGT-hAMSCs exposed to GDM-like conditions. Inhibition of the protein product of SERPINE1 (plasminogen activator inhibitor 1, PAI-1) suppressed the angiogenic properties of GDM-hAMSCs. Correlation analyses revealed that cord blood insulin levels in offspring strongly correlated with the number of nodes (r = 0.860; P = 0.001), junctions (r = 0.853; P = 0.002) and meshes (r = 0.816; P = 0.004) in tube formation assays. Finally, FGFR2 levels correlated positively with placental weight (r = 0.586; P = 0.028) and neonatal adiposity (r = 0.496; P = 0.014).

Conclusions

GDM exposure contributes to the angiogenic abilities of hAMSCs, which are further related to increased cord blood insulin and fetal adiposity. PAI-1 emerges as a potential key player of GDM-induced angiogenesis.

Human amniotic stem cells-derived exosmal miR-181a-5p and miR-199a inhibit melanogenesis and promote melanosome degradation in skin hyperpigmentation, respectively

BACKGROUND

Hyperpigmentation of skin is caused by an imbalance between the melanosome/melanin synthesis in melanocytes and the melanosome/melanin degradation in keratinocytes. Although studies showed that stem cells play a role in hypopigmentation, the underlying mechanisms are far not elucidated. Human amniotic stem cells (hASCs) including human amniotic mesenchymal stem cells (hAMSCs) and human amniotic epithelial stem cells (hAESCs) were considered to be a promising cell source for stem cells-based therapy of many diseases clinically due to their pluripotent potential, no tumorigenesis and immunogenicity, no ethical issues, and potent paracrine effects. Here, we reported that both hASCs and their conditional medium (CM) had a potent anti-hyperpigmentation in skin in vivo and in vitro.

METHODS

hAESCs and hAMSCs were identified by RT-PCR, flow cytometric analysis and immunofluorescence. Effects of hASCs and hASC-CM on pigmentation were evaluated in B16F10 cells stimulated with α-melanocyte-stimulating hormone (α-MSH), and mouse ears or human skin substitutes treated with ultraviolet radiation B (UVB). Expressions of the key proteins related with melanogenesis and autophagic flux were detected by western blot in B16F10 cells for further exploring the effects and the underlying mechanisms of hAESC-CM and hAMSC-CM on melanogenesis and melanosome degradation. The hAMSCs exosomes-derived miRNAs were determined by sequencing. RT-PCR, western blot, melanin content analysis and luciferase activity assay were used to determine the hypopigmentation of miR-181a-5p and miR-199a.

RESULTS

In our study, we observed that both hASCs and their CM significantly alleviated the α-MSH in B16F10 cells or UVB-induced hyperpigmentation in mouse ears or human skin substitutes by suppressing melanin synthesis and promoting melanosome degradation in vivo and in vitro. Furthermore, we demonstrated that miR-181a-5p and miR-199a derived from hASCs exosomes remarkably inhibited melanogenesis by suppressing MITF (microphthalmia-associated transcription factor) which is a master regulator for governing melanogenesis and promoting melanosome degradation through activating autophagy, respectively.

CONCLUSIONS

Our studies provided strong evidence that the conditional medium and exosomes derived from hAMSCs inhibit skin hyperpigmentation by suppressing melanogenesis and promoting melanosome degradation, indicating that the hASCs exosomes or their released microRNAs might be as reagents for cell-free therapy in hyperpigmented disorders clinically.