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Fluid shear triggers microvilli formation via mechanosensitive activation of TRPV6.

Miura S, Sato K, Kato-Negishi M, Teshima T, Takeuchi S - Nat Commun (2015)

Bottom Line: Here we demonstrate that fluid shear stress (FSS), an external mechanical cue, serves as a trigger for microvilli formation in human placental trophoblastic cells.We further reveal that the transient receptor potential, vanilloid family type-6 (TRPV6) calcium ion channel plays a critical role in flow-induced Ca(2+) influx and microvilli formation.TRPV6 regulates phosphorylation of Ezrin via a Ca(2+)-dependent phosphorylation of Akt; this molecular event is necessary for microvillar localization of Ezrin in response to FSS.

View Article: PubMed Central - PubMed

Affiliation: Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan.

ABSTRACT
Microvilli are cellular membrane protrusions present on differentiated epithelial cells, which can sense and interact with the surrounding fluid environment. Biochemical and genetic approaches have identified a set of factors involved in microvilli formation; however, the underlying extrinsic regulatory mechanism of microvilli formation remains largely unknown. Here we demonstrate that fluid shear stress (FSS), an external mechanical cue, serves as a trigger for microvilli formation in human placental trophoblastic cells. We further reveal that the transient receptor potential, vanilloid family type-6 (TRPV6) calcium ion channel plays a critical role in flow-induced Ca(2+) influx and microvilli formation. TRPV6 regulates phosphorylation of Ezrin via a Ca(2+)-dependent phosphorylation of Akt; this molecular event is necessary for microvillar localization of Ezrin in response to FSS. Our findings provide molecular insight into the microvilli-mediated mechanoresponsive cellular functions, such as epithelial absorption, signal perception and mechanotransduction.

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Microfluidic device for placental transfer analysis.(a) Schematic representation of the human placental barrier. In the placenta, maternal blood comes from the spiral artery and flows into intervillous space, into which placental villi carrying fetal blood capillaries project. Syncytiotrophoblasts, the placental barrier cells that cover the placental villi, develop a microvillar surface and function as a permeable barrier between maternal and fetal blood circulation. (b) Design of the microfluidic device for human placental transfer. PDMS microchannels (width, 1 mm; height, 200 μm) that correspond to maternal and fetal blood circulation are assembled with a vitrified collagen (VC) membrane and covalently bonded by O2 plasma treatment. The maternal microchannel has a chamber structure (φ=4 mm) that mimics the wide blood space of the intervillous space. (c) Fabricated PDMS device. Maternal and fetal channels were visualized by infusing red (maternal) and blue (fetal) ink. The material transfer between the microchannels was designed to only occur through the cell layer cultured on the VC membrane. Scale bar, 1 cm.
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f1: Microfluidic device for placental transfer analysis.(a) Schematic representation of the human placental barrier. In the placenta, maternal blood comes from the spiral artery and flows into intervillous space, into which placental villi carrying fetal blood capillaries project. Syncytiotrophoblasts, the placental barrier cells that cover the placental villi, develop a microvillar surface and function as a permeable barrier between maternal and fetal blood circulation. (b) Design of the microfluidic device for human placental transfer. PDMS microchannels (width, 1 mm; height, 200 μm) that correspond to maternal and fetal blood circulation are assembled with a vitrified collagen (VC) membrane and covalently bonded by O2 plasma treatment. The maternal microchannel has a chamber structure (φ=4 mm) that mimics the wide blood space of the intervillous space. (c) Fabricated PDMS device. Maternal and fetal channels were visualized by infusing red (maternal) and blue (fetal) ink. The material transfer between the microchannels was designed to only occur through the cell layer cultured on the VC membrane. Scale bar, 1 cm.

Mentions: Here we uncover that FSS serves as a critical external cue for microvilli formation in placental barrier cells. The placental barrier cells develop thousands of microvilli exposed to the maternal blood in the intervillous space and regulate material transfer between the maternal and fetal blood flow (Fig. 1a). We fabricate a multilayer microfluidic device to analyse material transport through the cells and to observe cellular responses to a broad range of FSS (Fig. 1b,c). Using this device, we show that both BeWo trophoblastic cells and villous trophoblasts form abundant microvilli of varying lengths depending on the flow rate, whereas the cells under static fluid conditions have sparse microvilli. Moreover, we demonstrate that the transient receptor potential, vanilloid family type-6 (TRPV6) calcium ion channel is essential in FSS-induced Ca2+ influx and microvilli formation in BeWo trophoblastic cells. We also identify the downstream phosphorylation signalling required for the microvilli formation.


Fluid shear triggers microvilli formation via mechanosensitive activation of TRPV6.

Miura S, Sato K, Kato-Negishi M, Teshima T, Takeuchi S - Nat Commun (2015)

Microfluidic device for placental transfer analysis.(a) Schematic representation of the human placental barrier. In the placenta, maternal blood comes from the spiral artery and flows into intervillous space, into which placental villi carrying fetal blood capillaries project. Syncytiotrophoblasts, the placental barrier cells that cover the placental villi, develop a microvillar surface and function as a permeable barrier between maternal and fetal blood circulation. (b) Design of the microfluidic device for human placental transfer. PDMS microchannels (width, 1 mm; height, 200 μm) that correspond to maternal and fetal blood circulation are assembled with a vitrified collagen (VC) membrane and covalently bonded by O2 plasma treatment. The maternal microchannel has a chamber structure (φ=4 mm) that mimics the wide blood space of the intervillous space. (c) Fabricated PDMS device. Maternal and fetal channels were visualized by infusing red (maternal) and blue (fetal) ink. The material transfer between the microchannels was designed to only occur through the cell layer cultured on the VC membrane. Scale bar, 1 cm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4660203&req=5

f1: Microfluidic device for placental transfer analysis.(a) Schematic representation of the human placental barrier. In the placenta, maternal blood comes from the spiral artery and flows into intervillous space, into which placental villi carrying fetal blood capillaries project. Syncytiotrophoblasts, the placental barrier cells that cover the placental villi, develop a microvillar surface and function as a permeable barrier between maternal and fetal blood circulation. (b) Design of the microfluidic device for human placental transfer. PDMS microchannels (width, 1 mm; height, 200 μm) that correspond to maternal and fetal blood circulation are assembled with a vitrified collagen (VC) membrane and covalently bonded by O2 plasma treatment. The maternal microchannel has a chamber structure (φ=4 mm) that mimics the wide blood space of the intervillous space. (c) Fabricated PDMS device. Maternal and fetal channels were visualized by infusing red (maternal) and blue (fetal) ink. The material transfer between the microchannels was designed to only occur through the cell layer cultured on the VC membrane. Scale bar, 1 cm.
Mentions: Here we uncover that FSS serves as a critical external cue for microvilli formation in placental barrier cells. The placental barrier cells develop thousands of microvilli exposed to the maternal blood in the intervillous space and regulate material transfer between the maternal and fetal blood flow (Fig. 1a). We fabricate a multilayer microfluidic device to analyse material transport through the cells and to observe cellular responses to a broad range of FSS (Fig. 1b,c). Using this device, we show that both BeWo trophoblastic cells and villous trophoblasts form abundant microvilli of varying lengths depending on the flow rate, whereas the cells under static fluid conditions have sparse microvilli. Moreover, we demonstrate that the transient receptor potential, vanilloid family type-6 (TRPV6) calcium ion channel is essential in FSS-induced Ca2+ influx and microvilli formation in BeWo trophoblastic cells. We also identify the downstream phosphorylation signalling required for the microvilli formation.

Bottom Line: Here we demonstrate that fluid shear stress (FSS), an external mechanical cue, serves as a trigger for microvilli formation in human placental trophoblastic cells.We further reveal that the transient receptor potential, vanilloid family type-6 (TRPV6) calcium ion channel plays a critical role in flow-induced Ca(2+) influx and microvilli formation.TRPV6 regulates phosphorylation of Ezrin via a Ca(2+)-dependent phosphorylation of Akt; this molecular event is necessary for microvillar localization of Ezrin in response to FSS.

View Article: PubMed Central - PubMed

Affiliation: Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan.

ABSTRACT
Microvilli are cellular membrane protrusions present on differentiated epithelial cells, which can sense and interact with the surrounding fluid environment. Biochemical and genetic approaches have identified a set of factors involved in microvilli formation; however, the underlying extrinsic regulatory mechanism of microvilli formation remains largely unknown. Here we demonstrate that fluid shear stress (FSS), an external mechanical cue, serves as a trigger for microvilli formation in human placental trophoblastic cells. We further reveal that the transient receptor potential, vanilloid family type-6 (TRPV6) calcium ion channel plays a critical role in flow-induced Ca(2+) influx and microvilli formation. TRPV6 regulates phosphorylation of Ezrin via a Ca(2+)-dependent phosphorylation of Akt; this molecular event is necessary for microvillar localization of Ezrin in response to FSS. Our findings provide molecular insight into the microvilli-mediated mechanoresponsive cellular functions, such as epithelial absorption, signal perception and mechanotransduction.

Show MeSH
Related in: MedlinePlus