Ethanol Exposure Increases miR‐140 in Extracellular Vesicles: Implications for Fetal Neural Stem Cell Proliferation and Maturation

Abstract

Background: Neural stem cells (NSCs) generate most of the neurons of the adult brain in humans, during the mid-first through second-trimester period. This critical neurogenic window is particularly vulnerable to prenatal alcohol exposure, which can result in diminished brain growth. Previous studies showed that ethanol (EtOH) exposure does not kill NSCs, but, rather, results in their depletion by influencing cell cycle kinetics and promoting aberrant maturation, in part, by altering NSC expression of key neurogenic miRNAs. NSCs reside in a complex microenvironment rich in extracellular vesicles, shown to traffic miRNA cargo between cells.Methods: We profiled the miRNA content of extracellular vesicles from control and EtOH-exposed ex vivo neurosphere cultures of fetal NSCs. We subsequently examined the effects of one EtOH-sensitive miRNA, miR-140-3p, on NSC growth, survival, and maturation.Results: EtOH exposure significantly elevates levels of a subset of miRNAs in secreted extracellular vesicles. Overexpression of one of these elevated miRNAs, miR-140-3p, and its passenger strand relative, miR-140-5p, significantly increased the proportion of S-phase cells while decreasing the proportion of G 0 /G 1 cells compared to controls. In contrast, while miR-140-3p knockdown had minimal effects on the proportion of cells in each phase of the cell cycle, knockdown of miR-140-5p significantly decreased the proportion of cells in G 2 /M phase. Furthermore, miR-140-3p overexpression, during mitogen-withdrawal-induced NSC differentiation, favors astroglial maturation at the expense of neural and oligodendrocyte differentiation.Conclusions: Collectively, the dysregulated miRNA content of extracellular vesicles following EtOH exposure may result in aberrant neural progenitor cell growth and maturation, explaining brain growth deficits associated with prenatal alcohol exposure.

miR-140-5p in Small Extracellular Vesicles From Human Papilla Cells Stimulates Hair Growth by Promoting Proliferation of Outer Root Sheath and Hair Matrix Cells

“…BMP2 was identified as the hub regulatory gene of miR-140-5p, which accounted for 6.96% of the total miRNA reads in P3-DP-EVs. Although few studies have investigated the role of miR-140-5p in dermatology, miR-140-5p expression is known to promote proliferation in dental pulp stem cells (Sun et al, 2017), neural stem cells (Tseng et al, 2019), and chondrocytes (Tao et al, 2017;Wang Z. et al, 2018). We showed that overexpression of miR-140-5p in human HFs was confirmed to stimulate ORSC and MxCs proliferation by treatment with overexpressed vesicular miR-140-5p, but was restricted by vesicular miR-140-5p inhibition.…”

Extracellular Vesicles in CNS Developmental Disorders

“…Furthermore, an in vivo model of developing zebrafish demonstrated that miR-153 levels decreased after ethanol exposure, consequently revealing impaired neurobehavioral development [ 102 ]. In vitro cultured NSCs were also used to understand the role of EVs in NSC development and differentiation during ethanol exposure [ 48 ]. In these studies, miR-140-3p was identified as another important miRNA affected by ethanol treatment, indicating that ethanol influences the expression of key differentiation-associated mRNA transcripts.…”

Role of Extracellular Vesicles in Substance Abuse and HIV-Related Neurological Pathologies

“…Additionally, miR-155 deficiency or TLR4 knockout protected mice from alcohol-induced neuroinflammation [148]. A fetal neural-stem-cell (NSCs) study found that 47 miRNAs, including miR-140-3p, miR-15b-3p, miR-340-5p, and miR-674-5p, were significantly upregulated in EVs from alcohol-treated NSCs [149]. Overexpression of miR-140-3p increased the number of S-phase cells and decreased the number of G 0 /G 1 cells, suggesting an increase in cell proliferation.…”

“…During NSC differentiation, overexpression of miR-140-3p increased the mRNA expression of GFAP (astrocytic marker) and decreased the expression of PDGFR α (an oligodendrocyte marker) as well as DCX and NeuN (neuronal markers), potentially promoting aberrant astrocytic differentiation of NSCs at the expense of differentiating to other cell lineages. This dysregulation of miRNA content may contribute to abnormal neurodevelopment linked with fetal alcohol syndrome disorder [ 149 ].…”