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"Mathieu, Maxime"
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Adipose tissue is a source of regenerative cells that augment the repair of skeletal muscle after injury
2023
Fibro-adipogenic progenitors (FAPs) play a crucial role in skeletal muscle regeneration, as they generate a favorable niche that allows satellite cells to perform efficient muscle regeneration. After muscle injury, FAP content increases rapidly within the injured muscle, the origin of which has been attributed to their proliferation within the muscle itself. However, recent single-cell RNAseq approaches have revealed phenotype and functional heterogeneity in FAPs, raising the question of how this differentiation of regenerative subtypes occurs. Here we report that FAP-like cells residing in subcutaneous adipose tissue (ScAT), the adipose stromal cells (ASCs), are rapidly released from ScAT in response to muscle injury. Additionally, we find that released ASCs infiltrate the damaged muscle, via a platelet-dependent mechanism and thus contribute to the FAP heterogeneity. Moreover, we show that either blocking ASCs infiltration or removing ASCs tissue source impair muscle regeneration. Collectively, our data reveal that ScAT is an unsuspected physiological reservoir of regenerative cells that support skeletal muscle regeneration, underlining a beneficial relationship between muscle and fat.
The dynamics of fibroadipogenic progenitors (FAPs) after muscle injury are crucial to ensure efficient regeneration. Here the authors show that a pool of FAPs originates from adipose tissue and are necessary for effective muscle regeneration.
Journal Article
Endogenous Mobilization of Mesenchymal Stromal Cells: A Pathway for Interorgan Communication?
by
Sengenès, Coralie
,
Sastourné-Arrey, Quentin
,
Casteilla, Louis
in
Adipose tissue
,
Animal biology
,
Blood platelets
2021
To coordinate specialized organs, inter-tissue communication appeared during evolution. Consequently, individual organs communicate their states
via
a vast interorgan communication network (ICN) made up of peptides, proteins, and metabolites that act between organs to coordinate cellular processes under homeostasis and stress. However, the nature of the interorgan signaling could be even more complex and involve mobilization mechanisms of unconventional cells that are still poorly described. Mesenchymal stem/stromal cells (MSCs) virtually reside in all tissues, though the biggest reservoir discovered so far is adipose tissue where they are named adipose stromal cells (ASCs). MSCs are thought to participate in tissue maintenance and repair since the administration of exogenous MSCs is well known to exert beneficial effects under several pathological conditions. However, the role of endogenous MSCs is barely understood. Though largely debated, the presence of circulating endogenous MSCs has been reported in multiple pathophysiological conditions, but the significance of such cell circulation is not known and therapeutically untapped. In this review, we discuss current knowledge on the circulation of native MSCs, and we highlight recent findings describing MSCs as putative key components of the ICN.
Journal Article
Awareness and Mitigation Management of Cultural Issues in France, the United Kingdom and Portugal - Proposal of Methodology for SME
2017
Cross-cultural issues have relevant impacts in the day-to-day life of the organisations and, particularly, for the Small and Medium Size (SME) organisations. The economic world is living tendency towards deterritorialisation, so that social space can no longer be wholly mapped in terms of territorial places, territorial distances and territorial borders. The boundaries are not more relevant in money, technology, goods and people movement, the current society is more of a multicultural dimensional one.In Europe, the small and medium-sized enterprises and entrepreneurs play a crucial role in the economy. The SMEs and entrepreneurs both operate in a ruthless and convoluted environment that is affected by different institutions and the respective national cultures of the European union (Muzychenko, 2008). Kluckhohn, a well-known American anthropologist and social theorist describes culture saying that human beings are made of conflicts with themselves and between each other, groups and nations that think, feel and act in a different manner. Allocating culture means sharing thoughts, reacting and solving problems (Muzychenko, 2008). As Hall (1990) points out, unlike common sense, the most difficult barrier to overcome and the most difficult to achieve is the one created by cultural differences.The main question that leads this research is: ‘How do(es) owner(s) or manager(s) of SMEs in France, the United Kingdom, and Portugal understand and prepare their organisations to lessen the cultural impact in the process of internationalization’? The research reached the understanding about the evaluation of awareness on cross-cultural impacts and the organisation behaviour and management to mitigate these impacts. A transversal, non-experimental methodology was used which is based on statistical analysis of data collected through an online structured survey.It was added some questions, as complementary and secondary information, on “ethical blindness”. From over 10 thousand of emails sent, 207 validated answer were collected. The main conclusion to be highlighted is that there is a true lack of knowledge to mitigate the cross-cultural issues in SMEs life and that students need to be trained at school before entering the professional environment (mainly be SMEs).Finally, this research proposes a methodology to be used by managers of SME’s, to analyse the cross-cultural issues and to improve the mitigation of those of impacts.
Dissertation
Diversification of human plasmacytoid predendritic cells in response to a single stimulus
by
Vargas, Pablo
,
Morillon, Antonin
,
Roman, Mabel San
in
Adaptive Immunity - immunology
,
Autocrine signalling
,
B7-1 Antigen - immunology
2018
Innate immune cells adjust to microbial and inflammatory stimuli through a process termed environmental plasticity, which links a given individual stimulus to a unique activated state. Here, we report that activation of human plasmacytoid predendritic cells (pDCs) with a single microbial or cytokine stimulus triggers cell diversification into three stable subpopulations (P1–P3). P1-pDCs (PD-L1
+
CD80
–
) displayed a plasmacytoid morphology and specialization for type I interferon production. P3-pDCs (PD-L1
–
CD80
+
) adopted a dendritic morphology and adaptive immune functions. P2-pDCs (PD-L1
+
CD80
+
) displayed both innate and adaptive functions. Each subpopulation expressed a specific coding- and long-noncoding-RNA signature and was stable after secondary stimulation. P1-pDCs were detected in samples from patients with lupus or psoriasis. pDC diversification was independent of cell divisions or preexisting heterogeneity within steady-state pDCs but was controlled by a TNF autocrine and/or paracrine communication loop. Our findings reveal a novel mechanism for diversity and division of labor in innate immune cells.
Plasmacytoid dendritic cells (pDCs) are known for their copious IFN-I production. Soumelis and colleagues show that functionally and transcriptomically distinct human pDC populations can be generated from a single microbial or cytokine stimulus.
Journal Article
Implementing patient derived organoids in functional precision medicine for patients with advanced colorectal cancer
by
Mathieu, Jacques R. R.
,
Gontran, Emilie
,
Sourrouille, Isabelle
in
Antigens
,
Apoptosis
,
Automation
2023
Background
Patient Derived Organoids (PDOs) emerged as the best technology to develop ex vivo tumor avatars. Whether drug testing on PDOs to identify efficient therapies will bring clinical utility by improving patient survival remains unclear. To test this hypothesis in the frame of clinical trials, PDO technology faces three main challenges to be implemented in routine clinical practices: i) generating PDOs with a limited amount of tumor material; ii) testing a wide panel of anti-cancer drugs; and iii) obtaining results within a time frame compatible with patient disease management. We aimed to address these challenges in a prospective study in patients with colorectal cancer (CRC).
Methods
Fresh surgical or core needle biopsies were obtained from patients with CRC. PDOs were established and challenged with a panel of 25 FDA-approved anti-cancer drugs (chemotherapies and targeted therapies) to establish a scoring method (‘chemogram’) identifying in vitro responders. The results were analyzed at the scale of the cohort and individual patients when the follow-up data were available.
Results
A total of 25 PDOs were successfully established, harboring 94% concordance with the genomic profile of the tumor they were derived from. The take-on rate for PDOs derived from core needle biopsies was 61.5%. A chemogram was obtained with a 6-week median turnaround time (range, 4–10 weeks). At least one hit (mean 6.16) was identified for 92% of the PDOs. The number of hits was inversely correlated to disease metastatic dissemination and the number of lines of treatment the patient received. The chemograms were compared to clinical data obtained from 8 patients and proved to be predictive of their response with 75% sensitivity and specificity.
Conclusions
We show that PDO-based drug tests can be achieved in the frame of routine clinical practice. The chemogram could provide clinicians with a decision-making tool to tailor patient treatment. Thus, PDO-based functional precision oncology should now be tested in interventional trials assessing its clinical utility for patients who do not harbor activable genomic alterations or have developed resistance to standard of care treatments.
Journal Article
Non-specific interactions govern cytosolic diffusion of nanosized objects in mammalian cells
2018
The diffusivity of macromolecules in the cytoplasm of eukaryotic cells varies over orders of magnitude and dictates the kinetics of cellular processes. However, a general description that associates the Brownian or anomalous nature of intracellular diffusion to the architectural and biochemical properties of the cytoplasm has not been achieved. Here we measure the mobility of individual fluorescent nanoparticles in living mammalian cells to obtain a comprehensive analysis of cytoplasmic diffusion. We identify a correlation between tracer size, its biochemical nature and its mobility. Inert particles with size equal or below 50 nm behave as Brownian particles diffusing in a medium of low viscosity with negligible effects of molecular crowding. Increasing the strength of non-specific interactions of the nanoparticles within the cytoplasm gradually reduces their mobility and leads to subdiffusive behaviour. These experimental observations and the transition from Brownian to subdiffusive motion can be captured in a minimal phenomenological model.
Journal Article
A coordinated progression of progenitor cell states initiates urinary tract development
2021
The kidney and upper urinary tract develop through reciprocal interactions between the ureteric bud and the surrounding mesenchyme. Ureteric bud branching forms the arborized collecting duct system of the kidney, while ureteric tips promote nephron formation from dedicated progenitor cells. While nephron progenitor cells are relatively well characterized, the origin of ureteric bud progenitors has received little attention so far. It is well established that the ureteric bud is induced from the nephric duct, an epithelial duct derived from the intermediate mesoderm of the embryo. However, the cell state transitions underlying the progression from intermediate mesoderm to nephric duct and ureteric bud remain unknown. Here we show that nephric duct morphogenesis results from the coordinated organization of four major progenitor cell populations. Using single cell RNA-seq and Cluster RNA-seq, we show that these progenitors emerge in time and space according to a stereotypical pattern. We identify the transcription factors Tfap2a/b and Gata3 as critical coordinators of this progenitor cell progression. This study provides a better understanding of the cellular origin of the renal collecting duct system and associated urinary tract developmental diseases, which may inform guided differentiation of functional kidney tissue.
Nephric duct (ND)-derived ureteric buds (UB) form the kidney collecting duct system, while ureteric tips promote nephron formation. Here the authors use single-cell RNA-seq and introduce Cluster RNA-seq to identify four progenitor populations in developing ND/UB regulated by the transcription factors Tfap2a/b and Gata3.
Journal Article
An atlas of white matter anatomy, its variability, and reproducibility based on constrained spherical deconvolution of diffusion MRI
2022
Virtual dissection of white matter (WM) using diffusion MRI tractography is confounded by its poor reproducibility. Despite the increased adoption of advanced reconstruction models, early region-of-interest driven protocols based on diffusion tensor imaging (DTI) remain the dominant reference for virtual dissection protocols. Here we bridge this gap by providing a comprehensive description of typical WM anatomy reconstructed using a reproducible automated subject-specific parcellation-based approach based on probabilistic constrained-spherical deconvolution (CSD) tractography. We complement this with a WM template in MNI space comprising 68 bundles, including all associated anatomical tract selection labels and associated automated workflows. Additionally, we demonstrate bundle inter- and intra-subject variability using 40 (20 test-retest) datasets from the human connectome project (HCP) and 5 sessions with varying b-values and number of b-shells from the single-subject Multiple Acquisitions for Standardization of Structural Imaging Validation and Evaluation (MASSIVE) dataset. The most reliably reconstructed bundles were the whole pyramidal tracts, primary corticospinal tracts, whole superior longitudinal fasciculi, frontal, parietal and occipital segments of the corpus callosum and middle cerebellar peduncles. More variability was found in less dense bundles, e.g., the fornix, dentato-rubro-thalamic tract (DRTT), and premotor pyramidal tract. Using the DRTT as an example, we show that this variability can be reduced by using a higher number of seeding attempts. Overall inter-session similarity was high for HCP test-retest data (median weighted-dice = 0.963, stdev = 0.201 and IQR = 0.099). Compared to the HCP-template bundles there was a high level of agreement for the HCP test-retest data (median weighted-dice = 0.747, stdev = 0.220 and IQR = 0.277) and for the MASSIVE data (median weighted-dice = 0.767, stdev = 0.255 and IQR = 0.338). In summary, this WM atlas provides an overview of the capabilities and limitations of automated subject-specific probabilistic CSD tractography for mapping white matter fasciculi in healthy adults. It will be most useful in applications requiring a reproducible parcellation-based dissection protocol, and as an educational resource for applied neuroimaging and clinical professionals.
[Display omitted]
(Top) shows the FWT pipeline for both CSTs, AF, and motor CC bundles. (Left to right) show the required input structural parcellation maps and a priori atlases for FWT and the resulting virtual dissection include/exclude VOIs. FWT provides two approaches to virtual dissection: (1) is a bundle-specific approach where streamlines are only seeded for the bundle of interest, (2) is a whole brain tractography followed by streamlines segmentation, (top right) shows output tractograms. (Middle) Group-averaged T1 and fODF images are generated from the HCP test-retest data, and FWT is applied to generate the HCP- atlas using the bundle-specific approach (1*). FWT's whole brain tracking and segmentation approach (2*) was applied to the HCP and MASSIVE dataset (right and left) and conducted model-based, and pair-wise similarity analyses and generated voxel-wise cumulative maps per bundle. FWT = Fun With Tracts, FS = FreeSurfer, MSBP = MultiScaleBrainParcellator, PD25 = NIST Parkinson's histological, JHU = John's Hopkins university, Juelich = Juelich university histological atlas, AC/PC = anterior commissure/posterior commissure) UKBB = UK Biobank, SUIT (spatially unbiased cerebellar atlas template), dMRI = diffusion magnetic resonance imaging, CSD = constrained spherical deconvolution, fODF = fiber orientation distribution function, CST = corticospinal tract, AF = arcuate fasciculus, CC = corpus callosum, HCP = human connectome project, MASSIVE = Multiple acquisitions for standardization of structural imaging validation and evaluation.
Journal Article
Fluorescent Dynamic Covalent Polymers for DNA Complexation and Templated Assembly
by
Lebrun, Aurélien
,
Ulrich, Sébastien
,
Gerbier, Philippe
in
Amino acids
,
Aqueous solutions
,
Arginine
2022
Dynamic covalent polymers (DCPs) offer opportunities as adaptive materials of particular interest for targeting, sensing and delivery of biological molecules. In this view, combining cationic units and fluorescent units along DCP chains is attractive for achieving optical probes for the recognition and delivery of nucleic acids. Here, we report on the design of acylhydrazone-based DCPs combining cationic arginine units with π-conjugated fluorescent moieties based on thiophene-ethynyl-fluorene cores. Two types of fluorescent building blocks bearing neutral or cationic side groups on the fluorene moiety are considered in order to assess the role of the number of cationic units on complexation with DNA. The (chir)optical properties of the building blocks, the DCPs, and their complexes with several types of DNA are explored, providing details on the formation of supramolecular complexes and on their stability in aqueous solutions. The DNA-templated formation of DCPs is demonstrated, which provides new perspectives on the assembly of fluorescent DCP based on the nucleic acid structure.
Journal Article
Cortical tracking of lexical speech units in a multi-talker background is immature in school-aged children
2023
Children have more difficulty perceiving speech in noise than adults. Whether this difficulty relates to an immature processing of prosodic or linguistic elements of the attended speech is still unclear. To address the impact of noise on linguistic processing per se, we assessed how babble noise impacts the cortical tracking of intelligible speech devoid of prosody in school-aged children and adults.
Twenty adults and twenty children (7-9 years) listened to synthesized French monosyllabic words presented at 2.5 Hz, either randomly or in 4-word hierarchical structures wherein 2 words formed a phrase at 1.25 Hz, and 2 phrases formed a sentence at 0.625 Hz, with or without babble noise. Neuromagnetic responses to words, phrases and sentences were identified and source-localized.
Children and adults displayed significant cortical tracking of words in all conditions, and of phrases and sentences only when words formed meaningful sentences. In children compared with adults, the cortical tracking was lower for all linguistic units in conditions without noise. In the presence of noise, the cortical tracking was similarly reduced for sentence units in both groups, but remained stable for phrase units. Critically, when there was noise, adults increased the cortical tracking of monosyllabic words in the inferior frontal gyri and supratemporal auditory cortices but children did not.
This study demonstrates that the difficulties of school-aged children in understanding speech in a multi-talker background might be partly due to an immature tracking of lexical but not supra-lexical linguistic units.
Journal Article