Ultraslow Myosin Molecular Motors of Placental Contractile Stem Villi in Humans

Lecarpentier, Yves; Claes, Victor; Lecarpentier, Édouard; Guérin, Catherine; Hébert, Jean-Louis; Arsalane, Abdelilah; Moumen, A.; Krokidis, Xénophon; Michel, Francine; Timbely, Oumar

doi:10.1371/journal.pone.0108814

Cited by 17 publications

(32 citation statements)

References 28 publications

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“…The load level was progressively decremented by successive steps of 0.1mN from isometric tension until zero-load. At each afterload level, PSV shortened at isotonic tension level (T) and constant velocity (V) [ 3 ]. The T-V relationship was constructed from the velocity (V) of 7 to 10 isotonic contractions, versus the isotonic load level normalized per cross-sectional area.…”

Section: Methodsmentioning

confidence: 99%

“…Human placental stem villi (PSV) have been shown to possess contractile properties [ 1 , 2 ] and the kinetics of myosin crossbridge (CB) molecular motors inside the extravascular part of PSV are dramatically slow [ 3 ]. A phenomenological approach of the thermodynamic behavior of myosin CBs is provided by the A. Huxley theory [ 4 ] which allows to determine kinetics and probabilities of several steps of the ATP-ADP-Pi-acto-myosin cycle [ 5 ].…”

Section: Introductionmentioning

confidence: 99%

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Statistical Mechanics of the Human Placenta: A Stationary State of a Near-Equilibrium System in a Linear Regime

Lecarpentier¹,

Claes

Hébert

et al. 2015

PLoS ONE

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All near-equilibrium systems under linear regime evolve to stationary states in which there is constant entropy production rate. In an open chemical system that exchanges matter and energy with the exterior, we can identify both the energy and entropy flows associated with the exchange of matter and energy. This can be achieved by applying statistical mechanics (SM), which links the microscopic properties of a system to its bulk properties. In the case of contractile tissues such as human placenta, Huxley’s equations offer a phenomenological formalism for applying SM. SM was investigated in human placental stem villi (PSV) (n = 40). PSV were stimulated by means of KCl exposure (n = 20) and tetanic electrical stimulation (n = 20). This made it possible to determine statistical entropy (S), internal energy (E), affinity (A), thermodynamic force (A / T) (T: temperature), thermodynamic flow (v) and entropy production rate (A / T x v). We found that PSV operated near equilibrium, i.e., A ≺≺ 2500 J/mol and in a stationary linear regime, i.e., (A / T) varied linearly with v. As v was dramatically low, entropy production rate which quantified irreversibility of chemical processes appeared to be the lowest ever observed in any contractile system.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Statistical Mechanics of the Human Placenta: A Stationary State of a Near-Equilibrium System in a Linear Regime

Lecarpentier¹,

Claes

Hébert

et al. 2015

PLoS ONE

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“…The low isometric tension reported in placental stem villi [43,50,51] can be partly explained by the low placental myosin content [52][53][54]. The extremely slow shortening velocity can be accounted for by the very low placental myosin ATPase activity [48,52,54].…”

Section: The Myofibroblast: a Contractile Cell Containing The Non-musmentioning

confidence: 97%

“…Then, the power stroke The main characteristic of NMII is that it is extremely slow. Kinetics of contractile NMII are dramatically slow [47,48]. Compared with striated or smooth muscles, the values for the CB detachment constant, the CB attachment constant, the catalytic constant, and the myosin ATPase activity are particularly low.…”

Section: The Myofibroblast: a Contractile Cell Containing The Non-musmentioning

confidence: 99%

The Myofibroblast: TGFβ-1, A Conductor which Plays a Key Role in Fibrosis by Regulating the Balance between PPARγ and the Canonical WNT Pathway

Lecarpentier¹,

Schussler

Claes

et al. 2017

Nuclear Receptor Research

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Abstract. Myofibroblasts are non-muscular contractile cells that occur physiologically in organs such as in stem villi of the human placenta during normal pregnancies. They have the ability to contract and relax in response to changes in the volume of the intervillous chamber. Myofibroblasts are also found in many pathological states, and are involved in wound healing and fibrosis processes in several organs such as liver, lung, kidney, and heart. During fibrosis, the contractile phenomenon is a relaxation-free mechanism, associated with the synthesis of collagen in the extracellular matrix (ECM), which leads to irreversible fibrosis, tissue retraction and finally apoptosis of the myofibroblasts. The molecular motor of myofibroblasts is the non-muscle myosin type II (NMII). Differentiation of fibroblasts into myofibroblast is largely regulated by the Transforming Growth Factor-β1 (TGF-β1). This system regulates the canonical WNT/β-catenin pathway in a positive manner and PPARγ in a negative manner. WNT/β-catenin promotes fibrosis while PPARγ prevents fibrosis. This review focuses on the contractile properties of myofibroblasts and on the TGF-β1 conductor which regulates the antagonism between PPARγ and the canonical WNT/β-catenin pathway.

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“…The artery and vein in the stem villi are surrounded by contractile cells, which are axially aligned [13][14][15][16][17][18][19][20]. Also, the contraction of the stem villi has been observed [14,[21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Influence of Branching Patterns and Active Contractions of the Villous Tree on Fetal and Maternal Blood Circulations in the Human Placenta

Kato¹

2018

Highlights on Hemodynamics

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In the human placenta, fetal blood circulates in the blood vessels of the villous tree while maternal one circulates in the intervillous space, the surroundings of the villous tree. Previously, the computational model of the villous tree, whose stem villi actively contract because of the contractile cells, has been developed. The result of the computation indicated that the displacement caused by the contraction would be helpful for the fetal and maternal circulations and can be combined with the other measurements for blood circulations in the placenta. Hypoxia in the placenta is classified into the following categories: preplacental hypoxia, uteroplacental hypoxia, and postplacental hypoxia. The number and the form of the terminal villi are altered by hypoxia. Assuming that increase in the terminal villi causes a higher shear elastic modulus of the placenta, this villous tree model is useful to estimate the influence of hypoxia on the blood circulations. In this chapter, how these three types of hypoxia influence the blood circulation in the placenta by the aforementioned computational model are discussed. While preplacental hypoxia and uteroplacental hypoxia would cause similar displacement in large regions, postplacental hypoxia would do vice versa. All the types might make the fetal and maternal blood circulations difficult.

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Ultraslow Myosin Molecular Motors of Placental Contractile Stem Villi in Humans

Cited by 17 publications

References 28 publications

Statistical Mechanics of the Human Placenta: A Stationary State of a Near-Equilibrium System in a Linear Regime

Statistical Mechanics of the Human Placenta: A Stationary State of a Near-Equilibrium System in a Linear Regime

The Myofibroblast: TGFβ-1, A Conductor which Plays a Key Role in Fibrosis by Regulating the Balance between PPARγ and the Canonical WNT Pathway

Influence of Branching Patterns and Active Contractions of the Villous Tree on Fetal and Maternal Blood Circulations in the Human Placenta

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