microRNA-31 modulates skeletal patterning in the sea urchin embryos

Abstract

MicroRNAs (miRNAs) are small non-coding RNAs that repress the translation and reduce the stability of target mRNAs in animal cells. microRNA-31 (miR-31) is known to play a role in cancer, bone formation and lymphatic development. However, studies to understand the function of miR-31 in embryogenesis have been limited. We examined the regulatory role of miR-31 in early development using the sea urchin as a model. miR-31 is expressed at all stages of development and its knockdown (KD) disrupts the patterning and function of primary mesenchyme cells (PMCs), which form the embryonic skeleton spicules. We identified that miR-31 directly represses Pmar1, Alx1, Snail and VegfR7 within the PMC gene regulatory network using reporter constructs. Further, blocking the miR-31-mediated repression of Alx1 and/or VegfR7 in the developing embryo resulted in defects in PMC patterning and skeletogenesis. The majority of the mislocalized PMCs in miR-31 KD embryos did not express VegfR10, indicating that miR-31 regulates VegfR gene expression within PMCs. In addition, miR-31 indirectly suppresses Vegf3 expression in the ectoderm. These results indicate that miR-31 coordinately suppresses genes within the PMCs and in the ectoderm to impact PMC patterning and skeletogenesis. This study identifies the novel function and molecular mechanism of miR-31-mediated regulation in the developing embryo.

MicroRNA‐31a‐5p from aging BMSCs links bone formation and resorption in the aged bone marrow microenvironment

“…It has been reported that miR‐31a‐5p negatively regulates skeletogenesis and osteogenesis (Deng, Wu et al., 2013; Jin et al., 2016; Stepicheva, & Song, 2015; Weilner et al., 2016). Previous studies also demonstrated that decreased stemness and increased senescence are the primary causes of declines in osteogenic differentiation of BMSCs (Fehrer, & Lepperdinger, 2005; Zhou et al., 2016).…”

The small GTPase Arf6 regulates sea urchin morphogenesis

“…The temporal and spatial distribution of Arf6 were detected with the Arf6 in situ hybridization probe as previously described (Stepicheva et al, 2015; Stepicheva and Song, 2015). Arf6 coding sequence (Fig.…”

Function and regulation of microRNA‐31 in development and disease

“…miR‐31 may be one of the most highly abundant miRNAs that is ubiquitously expressed during Strongylocentrotus purpuratus (sea urchin) early development (Song et al, ; Stepicheva and Song, ). The knockdown of miR‐31 in the sea urchin embryos resulted in a range of dose‐dependent phenotypes, including the formation of extra cells and cell clumps in the blastocoel of the embryo, gut widening and reduction of the embryo size, as well as skeletogenesis defects (discussed below) (Stepicheva and Song, ).…”

“…The role of miR‐31 in regulating skeletogenesis is not restricted to vertebrates; indeed, this function seems to be a conserved mechanism in invertebrates. miR‐31 is critical for regulation of skeletogenesis in the sea urchin embryo (Stepicheva and Song, ), an echinoderm and a sister group to the chordates (McClay, ). Sea urchin embryos undergo less complex skeletogenesis than vertebrates.…”

“…The complexity of the signals received by the PMCs is not known, but the process of PMC positioning or patterning is, in part, dependent on VEGF (Vascular Endothelial Growth Factor) signaling, ALK4/5/7 (Transforming Growth Factor Beta receptors), SLC26A2/7 (Solute Carriers 26a2 and 7), LOX (Lipoxygenase), and BMP5/8 (Bone Morphogenetic Proteins 5 and 8) (Duloquin et al, ; Adomako‐Ankomah and Ettensohn, , ; Piacentino et al, , ,). Knockdown of miR‐31 resulted in a significant decrease in the length of dorsoventral connecting rods, formation of extra tri‐radiates, as well as PMC patterning defects in the sea urchin gastrulae (Stepicheva and Song, ). miR‐31 directly suppresses at least three transcription factors ( SpPmar1 , SpAlx1 , and SpSnail ) and one effector gene ( SpVegfr7 ) within the sea urchin skeletogenic gene regulatory network.…”