Publications by authors named "Samah Rekima"

Objective: Peroxisome Proliferator-Activated Receptors (PPARs) are nuclear receptors involved in the control of lipid metabolism. The PPARα isoform is highly expressed in brown adipose tissue (BAT). However, its precise role in BAT remains unclear.

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Inducing the neogenesis of pancreatic insulin-producing β cells holds great promise for diabetes research. However, non-toxic compounds with such activities remain to be discovered. Herein, we report the identification of RSPO1, a key agonist of the Wnt/β-catenin pathway, as an inducer of β cell replication.

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The development of bone-filling biomaterials capable of delivering in situ bone growth promoters or therapeutic agents is a key area of research. We previously developed a biomaterial constituting biphasic calcium phosphate (BCP) microparticles embedded in an autologous blood or plasma clot, which induced bone-like tissue formation in ectopic sites and mature bone formation in orthotopic sites, in small and large animals. More recently, we showed that activated carbon (AC) fiber cloth is a biocompatible material that can be used, due to its multiscale porosity, as therapeutic drug delivery system.

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Article Synopsis
  • Critical bone defect repair is challenging, and calcium-deficient apatites (CDA) are being studied as biocompatible materials that aid in bone healing.
  • Previous research showed that using activated carbon cloths (ACC) coated with CDA or strontium-doped CDA can accelerate bone repair in rats, especially in the short term.
  • This study further examines the long-term effectiveness of these patches, finding that strontium-doped patches notably enhance bone quality and integrate well without harmful debris, suggesting they are effective biomaterials for bone reconstruction.
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White adipocytes store energy differently than brown and brite adipocytes which dissipate energy under the form of heat. Studies have shown that adipocytes are able to respond to bacteria thanks to the presence of Toll-like receptors at their surface. Despite this, little is known about the involvement of each class of adipocytes in the infectious response.

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Numerous studies have shown that the recruitment and activation of thermogenic adipocytes, which are brown and beige/brite, reduce the mass of adipose tissue and normalize abnormal glycemia and lipidemia. However, the impact of these adipocytes on the inflammatory state of adipose tissue is still not well understood, especially in response to endotoxemia, which is a major aspect of obesity and metabolic diseases. First, we analyzed the phenotype and metabolic function of white and brite primary adipocytes in response to lipopolysaccharide (LPS) treatment in vitro.

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Background: Cancer cells cooperate with cells that compose their environment to promote tumor growth and invasion. Among them, adipocytes provide lipids used as a source of energy by cancer cells and adipokines that contribute to tumor expansion. Mechanisms supporting the dynamic interactions between cancer cells and stromal adipocytes, however, remain unclear.

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Inherent immune suppression represents a major challenge in the treatment of human cancer. The extracellular matrix molecule tenascin-C promotes cancer by multiple mechanisms, yet the roles of tenascin-C in tumor immunity are incompletely understood. Using a 4NQO-induced oral squamous cell carcinoma (OSCC) model with abundant and absent tenascin-C, we demonstrated that tenascin-C enforced an immune-suppressive lymphoid stroma via CCL21/CCR7 signaling, leading to increased metastatic tumors.

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During kidney development, WNT/β-catenin signalling has to be tightly controlled to ensure proliferation and differentiation of nephron progenitor cells. Here, we show in mice that the signalling molecules RSPO1 and RSPO3 act in a functionally redundant manner to permit WNT/β-catenin signalling and their genetic deletion leads to a rapid decline of nephron progenitors. By contrast, tissue specific deletion in cap mesenchymal cells abolishes mesenchyme to epithelial transition (MET) that is linked to a loss of expression, absence of SMAD1/5 phosphorylation and a concomitant failure to activate and thus explaining the observed phenotype on a molecular level.

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Background: Successful prevention of food allergy requires the identification of the factors adversely affecting the capacity to develop oral tolerance to food antigen in early life.

Objectives: This study sought to determine whether oral exposure to Dermatophagoides pteronyssinus through breast milk affects gut mucosal immunity with long-term effects on IgE-mediated food allergy susceptibility.

Methods: Gut immunity was explored in 2-week-old mice breast-fed by mothers exposed to D pteronyssinus, protease-inactivated D pteronyssinus, or to PBS during lactation.

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Oxylipins are metabolized from dietary ω3 and ω6 polyunsaturated fatty acids and are involved in an inflammatory response. Adipose tissue inflammatory background is a key factor of metabolic disorders and it is accepted that dietary fatty acids, in terms of quality and quantity, modulate oxylipin synthesis in this tissue. Moreover, it has been reported that diet supplementation in ω3 polyunsaturated fatty acids resolves some inflammatory situations.

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The recent characterization of functional brown adipose tissue in adult humans has opened new perspectives for regulation of energy expenditure with respect to obesity and diabetes. Furthermore, dietary recommendations have taken into account the insufficient dietary intake of ω3 PUFAs and the concomitant excessive intake of ω6 PUFA associated with the occurrence of overweight/obesity. We aimed to study whether ω3 PUFAs could play a role in the recruitment and function of energy-dissipating brown/brite adipocytes.

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The recent demonstration that pancreatic α cells can be continuously regenerated and converted into β-like cells upon ectopic expression of opened new avenues of research in the endocrine cell differentiation and diabetes fields. To determine whether such plasticity was also shared by δ cells, we generated and characterized transgenic animals that express specifically in somatostatin-expressing cells. We demonstrate that the ectopic expression of in δ cells is sufficient to induce their conversion into functional β-like cells.

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Cellular fibronectin (FN) and tenascin-C (TNC) are prominent development- and disease-associated matrix components with pro- and anti-adhesive activity, respectively. Whereas both are present in the tumour vasculature, their functional interplay on vascular endothelial cells remains unclear. We have previously shown that basally-oriented deposition of a FN matrix restricts motility and promotes junctional stability in cultured endothelial cells and that this effect is tightly coupled to expression of FN.

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Functional interplay between tumour cells and their neoplastic extracellular matrix plays a decisive role in malignant progression of carcinomas. Here we provide a comprehensive data set of the human HNSCC-associated fibroblast matrisome. Although much attention has been paid to the deposit of collagen, we identify oncofetal fibronectin (FN) as a major and obligate component of the matrix assembled by stromal fibroblasts from head and neck squamous cell carcinomas (HNSCC).

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Glioblastomas are the most common primary brain tumors, highly vascularized, infiltrating, and resistant to current therapies. This cancer leads to a fatal outcome in less than 18 months. The aggressive behavior of glioblastomas, including resistance to current treatments and tumor recurrence, has been attributed to glioma stemlike/progenitor cells.

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Background: Pearl millet landraces display an important variation in their cycle duration. This diversity contributes to the stability of crop production in the Sahel despite inter-annual rainfall fluctuation. Conservation of phenological diversity is important for the future of pearl millet improvement and sustainable use.

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Article Synopsis
  • Early farmers domesticated crops during the Neolithic revolution by selecting certain traits, particularly focusing on the reduction of branching in cereals, which is linked to the gene Teosinte-branched1 (Tb1).
  • In this study, researchers examined the role of the Tb1 orthologue (Pgtb1) in the domestication of pearl millet, revealing that while it plays a role, its influence is weaker compared to maize.
  • The findings indicate that there may be parallel evolution between pearl millet and maize regarding regions near the Tb1 gene, despite significant genetic differences and a lengthy divergence period of their wild ancestors.
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