Publications by authors named "Richard Michel"

Cancer cells are usually found to be softer than normal cells, but their stiffness changes when they are in contact with different environments because of mechanosensitivity. For example, they adhere to a given substrate by tuning their cytoskeleton, thus affecting their rheological properties. This mechanism could become efficient when cancer cells invade the surrounding tissues, and they have to remodel their cytoskeleton in order to achieve particular deformations.

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LINC complexes are crucial for the response of muscle cell precursors to the rigidity of their environment, but the mechanisms explaining this behaviour are not known. Here we show that pathogenic mutations in LMNA or SYNE-1 responsible for severe muscle dystrophies reduced the ability of human muscle cell precursors to adapt to substrates of different stiffness. Plated on muscle-like stiffness matrix, mutant cells exhibited contractile stress fibre accumulation, increased focal adhesions, and higher traction force than controls.

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Article Synopsis
  • Living cells exert forces on their surfaces through adhesive contacts, enabling shape changes and tension build-up in their cytoskeleton during migration.
  • Traction force microscopy (TFM) allows us to visualize these forces, but understanding the detailed mechanics of migration requires complementary rheological models that link cytoskeletal tension and myosin activity.
  • By solving a PDE using a finite-element approach, the study explores how well these models can predict traction forces in cell migration, confirming that the model's parameters can consistently explain observed force patterns based on cell geometry.
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Urinary tract infection (UTI) is one of the most prevalent infections in humans. In ≥80% of cases, the etiologic agents are strains of uropathogenic Escherichia coli (UPEC), which commonly reside in the gastrointestinal tract. Lactobacilli have been shown to prevent UTI reoccurrence by restoring the urogenital microbiota when administered vaginally or orally.

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The migration of tumor cells of different degrees of invasivity is studied, on the basis of the traction forces exerted in time on soft substrates (Young modulus∼10 kPa). It is found that the outliers of the traction stresses can be an effective indicator to distinguish cancer cell lines of different invasiveness. Here, we test two different epithelial bladder cancer cell lines, one invasive (T24), and a less invasive one (RT112).

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Background: Fibroblast growth factor 23 (FGF23) is a phosphaturic factor and a suppressor of 1alpha-hydroxylase activity in the kidney. Although its importance in chronic kidney disease (CKD) has been demonstrated in adults, there is little information in pediatric patients.

Objectives: The aims of this study were: 1) to determine reference values for FGF23 serum levels according to glomerular filtration rate (GFR) (measured by the reference standard, inulin clearance), gender, and age; and 2) to evaluate the effects of different etiologies and treatments on FGF23 serum levels in a prospective single-center cohort of 227 CKD children (119 boys).

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Article Synopsis
  • - Osteocalcin, a hormone linked to energy metabolism, may influence fat cells (adipocytes) and bone density in chronic kidney disease (CKD), although this has been underexplored.
  • - A study involving 61 CKD patients measured levels of osteocalcin, adiponectin, and leptin, and used advanced imaging (HR-pQCT) to assess bone density and structure.
  • - Results indicated that higher levels of osteocalcin are positively associated with adiponectin, while adiponectin levels show an inverse relationship with bone mineral density and structural parameters, highlighting new insights into the interplay between bone health and fat signaling in CKD.
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