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

Lecarpentier, Yves; Claes, Victor; Hébert, Jean-Louis; Krokidis, Xénophon; Blanc, François-Xavier; Michel, Francine; Timbely, Oumar

doi:10.1371/journal.pone.0142471

Cited by 11 publications

(18 citation statements)

References 45 publications

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“…The type II non-muscle myosin (NMII) represents the molecular motor of the myofibroblast cell. All the muscle and non-muscle contractile tissues studied show a hyperbolic tension-velocity relationship [13,14]. It is therefore possible to apply Huxley's formalism to them.…”

Section: Discussionmentioning

confidence: 99%

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Comparative Statistical Mechanics of Muscle and Non-Muscle Contractile Systems: Stationary States of Near-Equilibrium Systems in A Linear Regime

Lecarpentier¹,

Claes

Krokidis³

et al. 2017

Entropy

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Abstract:A. Huxley's equations were used to determine the mechanical properties of muscle myosin II (MII) at the molecular level, as well as the probability of the occurrence of the different stages in the actin-myosin cycle. It was then possible to use the formalism of statistical mechanics with the grand canonical ensemble to calculate numerous thermodynamic parameters such as entropy, internal energy, affinity, thermodynamic flow, thermodynamic force, and entropy production rate. This allows us to compare the thermodynamic parameters of a non-muscle contractile system, such as the normal human placenta, with those of different striated skeletal muscles (soleus and extensor digitalis longus) as well as the heart muscle and smooth muscles (trachea and uterus) in the rat. In the human placental tissues, it was observed that the kinetics of the actin-myosin crossbridges were considerably slow compared with those of smooth and striated muscular systems. The entropy production rate was also particularly low in the human placental tissues, as compared with that observed in smooth and striated muscular systems. This is partly due to the low thermodynamic flow found in the human placental tissues. However, the unitary force of non-muscle myosin (NMII) generated by each crossbridge cycle in the myofibroblasts of the human placental tissues was similar in magnitude to that of MII in the myocytes of both smooth and striated muscle cells. Statistical mechanics represents a powerful tool for studying the thermodynamics of all contractile muscle and non-muscle systems.

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Section: Discussionmentioning

confidence: 99%

“…In this study, we compared statistical mechanics in muscle and non-muscle contractile systems. A number of studies from our laboratory on this subject have already been published [12][13][14]. However, for the first time, this study focuses on the differences in statistical mechanics observed between muscle and non-muscle structures.…”

Section: Introductionmentioning

confidence: 99%

Comparative Statistical Mechanics of Muscle and Non-Muscle Contractile Systems: Stationary States of Near-Equilibrium Systems in A Linear Regime

Lecarpentier¹,

Claes

Krokidis³

et al. 2017

Entropy

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“…Nevertheless, the cross-brigde actin-myosin of NMIIA single force is same order of magnitude compared with muscle myosin II (MII). Thermodynamic force, thermodynamic flow and thermodynamic entropy production rate are rarely low [ 147 ]. This explains why this stationary contractile system operates near-equilibrium.…”

Section: Introductionmentioning

confidence: 99%

“…The extremely slow shortening velocity can be accounted for by the very low placental myosin ATPase activity which has an essential role for the association/dissociation of actin from the NMIIA head [ 145 , 149 ]. In placental stem villi, a low isometric tension has been reported [ 147 ]. This can be explained by the low placental myosin content and the low placental myosin ATPase activity [ 148 ].…”

Section: Introductionmentioning

confidence: 99%

Interactions between TGF-β1, canonical WNT/β-catenin pathway and PPAR γ in radiation-induced fibrosis

Lecarpentier²,

et al. 2017

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Radiation therapy induces DNA damage and inflammation leading to fibrosis. Fibrosis can occur 4 to 12 months after radiation therapy. This process worsens with time and years. Radiation-induced fibrosis is characterized by fibroblasts proliferation, myofibroblast differentiation, and synthesis of collagen, proteoglycans and extracellular matrix. Myofibroblasts are non-muscle cells that can contract and relax. Myofibroblasts evolve towards irreversible retraction during fibrosis process. In this review, we discussed the interplays between transforming growth factor-β1 (TGF-β1), canonical WNT/β-catenin pathway and peroxisome proliferator-activated receptor gamma (PPAR γ) in regulating the molecular mechanisms underlying the radiation-induced fibrosis, and the potential role of PPAR γ agonists. Overexpression of TGF-β and canonical WNT/β-catenin pathway stimulate fibroblasts accumulation and myofibroblast differentiation whereas PPAR γ expression decreases due to the opposite interplay of canonical WNT/β-catenin pathway. Both TGF-β1 and canonical WNT/β-catenin pathway stimulate each other through the Smad pathway and non-Smad pathways such as phosphatidylinositol 3-kinase/serine/threonine kinase (PI3K/Akt) signaling. WNT/β-catenin pathway and PPAR γ interact in an opposite manner. PPAR γ agonists decrease β-catenin levels through activation of inhibitors of the WNT pathway such as Smad7, glycogen synthase kinase-3 (GSK-3 β) and dickkopf-related protein 1 (DKK1). PPAR γ agonists also stimulate phosphatase and tensin homolog (PTEN) expression, which decreases both TGF-β1 and PI3K/Akt pathways. PPAR γ agonists by activating Smad7 decrease Smads pathway and then TGF-β signaling leading to decrease radiation-induced fibrosis. TGF-β1 and canonical WNT/β-catenin pathway promote radiation-induced fibrosis whereas PPAR γ agonists can prevent radiation-induced fibrosis.

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“…However, the NMII CB unitary force is of the same order of magnitude when compared with MII. From a thermodynamic point of view, the thermodynamic force, the thermodynamic flow, and the entropy production rate are extremely low [49]. This explains why this stationary contractile system operates as a near-equilibrium system.…”

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

Cited by 11 publications

References 45 publications

Comparative Statistical Mechanics of Muscle and Non-Muscle Contractile Systems: Stationary States of Near-Equilibrium Systems in A Linear Regime

Comparative Statistical Mechanics of Muscle and Non-Muscle Contractile Systems: Stationary States of Near-Equilibrium Systems in A Linear Regime

Interactions between TGF-β1, canonical WNT/β-catenin pathway and PPAR γ in radiation-induced fibrosis

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

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