Effectiveness of an individualized home-based physical activity program in surgery-free non-endarterectomized asymptomatic stroke patients: a study protocol for the PACAPh interventional randomized trial.

BACKGROUND: Carotid atherosclerotic plaques remain silent until their rupture, which may lead to detrimental ischemic events such as strokes. This is due, in part, to intraplaque hemorrhages (IPH) and the resulting inflammatory processes, which may promote carotid plaque vulnerability. Currently, the benefits of carotid endarterectomy remain unclear for asymptomatic patients. Interestingly, the completion of physical activity (PA) may have beneficial effects; however, the paucity of current data warrants robust longitudinal interventions. We therefore aim to study the effects of a 6-month longitudinal personalized home-based PA program on IPH, biological, and inflammatory markers in asymptomatic stroke patients. METHODS: Eighty patients (≥ 18 years old) will be recruited for the Physical Activity and Carotid Atherosclerotic Plaque Hemorrhage (PACAPh) clinical trial from the Hospices Civils de Lyon. Patients will be eligible if they present with carotid stenosis ≥ 50% and are asymptomatic from any ischemic events for at least 6 months. Recruited patients will be randomized into either a PA or a control group, and assessed at baseline and after 6 months. At both time points, all patients will be assessed using magnetic resonance imaging to assess IPH, blood sampling to measure inflammatory markers and monocytic phenotyping, PA and sedentary behavior questionnaires, 6-min walking test, and maximal isometric quadricep contraction test. The randomized PA intervention will consist of reaching a daily walking step goal individually tailored to each patient. Steps will be collected using a wirelessly connected wristband. The number of steps completed by individuals in the PA group will be re-evaluated bimonthly to encourage walking habits. DISCUSSION: The PACAPh study is the first of its kind representing a feasible, easily accessible therapeutic strategy for asymptomatic stroke patients. We hypothesize that the personalized home-based PA program will reduce IPH and modulate inflammatory and biological parameters in patients presenting with carotid plaques. If the results of the PACAPh study prove to be beneficial on such health parameters, the implementation of such kind of intervention in the daily treatment of these patients would be an advantageous and cost-effective practice to adopt globally. TRIAL REGISTRATION: This study has been approved by the National Ethics Committee (IDRCB:2019-A01543-54/SI:19.06.21.40640). ClinicalTrials.gov NCT04053166.

Interplay between FLI-1 and the LDB1 complex in murine erythroleukemia cells and during megakaryopoiesis.

Transcription factors are key players in a broad range of cellular processes such as cell-fate decision. Understanding how they act to control these processes is of critical importance for therapy purposes. FLI-1 controls several hematopoietic lineage differentiation including megakaryopoiesis and erythropoiesis. Its aberrant expression is often observed in cancer and is associated with poor prognosis. We showed that FLI-1 interacts with the LDB1 complex, which also plays critical roles in erythropoiesis and megakaryopoiesis. In this study, we aimed to unravel how FLI-1 and the LDB1 complex act together in murine erythroleukemia cells and in megakaryocyte. Combining omics techniques, we show that FLI-1 enables the recruitment of the LDB1 complex to regulatory sequences of megakaryocytic genes and to enhancers. We show as well for the first time that FLI-1 is able to modulate the 3D chromatin organization by promoting chromatin looping between enhancers and promoters most likely through the LDB1 complex.

Myogenic Progenitor Cells Exhibit Type I Interferon-Driven Proangiogenic Properties and Molecular Signature During Juvenile Dermatomyositis.

OBJECTIVE: Juvenile dermatomyositis (JDM) is an inflammatory pediatric myopathy characterized by focal capillary loss in muscle, followed by progressive recovery upon adequate treatment with immunomodulating drugs, although some patients remain refractory to treatment. While the underlying mechanism of capillary depletion remains uncertain, recent studies have identified an up-regulation of type I interferon (IFN) expression specific to JDM. Given that myogenic precursor cells (MPCs) exert proangiogenic activity during normal skeletal muscle regeneration, we hypothesized that they may also modulate vascular remodeling/angiogenesis during JDM. The aim of this study was to investigate that hypothesis. METHODS: Human cell cocultures were used to analyze angiogenic properties in patients with JDM, patients with Duchenne's muscular dystrophy (DMD) (control patients for vascular remodeling), and healthy control subjects. Transcriptome analysis was used to examine muscle-derived MPCs. Histologic analysis of type I IFN in muscle biopsy samples was also performed. RESULTS: Using human cell cocultures, we showed highly angiogenic properties of MPCs from JDM patients in association with the expression of an angiogenic molecular signature. Transcriptome analysis of MPCs freshly isolated from muscle samples revealed type I IFN as the master regulator of the most up-regulated genes in JDM-derived MPCs. Functionally, treatment of normal MPCs with type I IFN recapitulated the molecular pattern and the proangiogenic functions of JDM-derived MPCs. In vivo histologic investigation showed that MPCs synthesized type I IFN and major proangiogenic molecules in JDM muscle. Moreover, MPCs derived from JDM muscles that were characterized by strong vasculopathy produced higher levels of type I IFN, confirming MPCs as a cellular source of type I IFN during JDM, and this correlated with the severity of the disease. CONCLUSION: These results demonstrate a new type I IFN pathway in JDM that activates the production of angiogenic effectors by MPCs, triggering their proangiogenic function to promote vessel recovery and muscle reconstruction.

Coupling between Myogenesis and Angiogenesis during Skeletal Muscle Regeneration Is Stimulated by Restorative Macrophages.

In skeletal muscle, new functions for vessels have recently emerged beyond oxygen and nutrient supply, through the interactions that vascular cells establish with muscle stem cells. Here, we demonstrate in human and mouse that endothelial cells (ECs) and myogenic progenitor cells (MPCs) interacted together to couple myogenesis and angiogenesis in vitro and in vivo during skeletal muscle regeneration. Kinetics of gene expression of ECs and MPCs sorted at different time points of regeneration identified three effectors secreted by both ECs and MPCs. Apelin, Oncostatin M, and Periostin were shown to control myogenesis/angiogenesis coupling in vitro and to be required for myogenesis and vessel formation during muscle regeneration in vivo. Furthermore, restorative macrophages, which have been previously shown to support myogenesis in vivo, were shown in a 3D triculture model to stimulate myogenesis/angiogenesis coupling, notably through Oncostatin M production. Our data demonstrate that restorative macrophages orchestrate muscle regeneration by controlling myogenesis/angiogenesis coupling.

Notch Stimulates Both Self-Renewal and Lineage Plasticity in a Subset of Murine CD9High Committed Megakaryocytic Progenitors.

This study aimed at reinvestigating the controversial contribution of Notch signaling to megakaryocytic lineage development. For that purpose, we combined colony assays and single cells progeny analyses of purified megakaryocyte-erythroid progenitors (MEP) after short-term cultures on recombinant Notch ligand rDLL1. We showed that Notch activation stimulated the SCF-dependent and preferential amplification of Kit+ erythroid and bipotent progenitors while favoring commitment towards the erythroid at the expense of megakaryocytic lineage. Interestingly, we also identified a CD9High MEP subset that spontaneously generated almost exclusively megakaryocytic progeny mainly composed of single megakaryocytes. We showed that Notch activation decreased the extent of polyploidization and maturation of megakaryocytes, increased the size of megakaryocytic colonies and surprisingly restored the generation of erythroid and mixed colonies by this CD9High MEP subset. Importantly, the size increase of megakaryocytic colonies occurred at the expense of the production of single megakaryocytes and the restoration of colonies of alternative lineages occurred at the expense of the whole megakaryocytic progeny. Altogether, these results indicate that Notch activation is able to extend the number of divisions of MK-committed CD9High MEPs before terminal maturation while allowing a fraction of them to generate alternative lineages. This unexpected plasticity of MK-committed progenitors revealed upon Notch activation helps to better understand the functional promiscuity between megakaryocytic lineage and hematopoietic stem cells.

Instructive role of M-CSF on commitment of bipotent myeloid cells involves ERK-dependent positive and negative signaling.

M-CSF and G-CSF are instructive cytokines that specifically induce differentiation of bipotent myeloid progenitors into macrophages and granulocytes, respectively. Through morphology and colony assay studies, flow cytometry analysis of specific markers, and expression of myeloid transcription factors, we show here that the Eger/Fms cell line is composed of cells whose differentiation fate is instructed by M-CSF and G-CSF, thus representing a good in vitro model of myeloid bipotent progenitors. Consistent with the essential role of ERK1/2 during macrophage differentiation and defects of macrophagic differentiation in native ERK1(-/-) progenitors, ERK signaling is strongly activated in Eger/Fms cells upon M-CSF-induced macrophagic differentiation but only to a very small extent during G-CSF-induced granulocytic differentiation. Previous in vivo studies indicated a key role of Fli-1 in myeloid differentiation and demonstrated its weak expression during macrophagic differentiation with a strong expression during granulocytic differentiation. Here, we demonstrated that this effect could be mediated by a differential regulation of protein kinase Cδ (PKCd) on Fli-1 expression in response to M-CSF and G-CSF. With the use of knockdown of PKCd by small interfering RNA, we demonstrated that M-CSF activates PKCd, which in turn, inhibits Fli-1 expression and granulocytic differentiation. Finally, we studied the connection between ERK and PKCd and showed that in the presence of the MEK inhibitor U0126, PKCd expression is decreased, and Fli-1 expression is increased in response to M-CSF. Altogether, we demonstrated that in bipotent myeloid cells, M-CSF promotes macrophagic over granulocytic differentiation by inducing ERK activation but also PKCd expression, which in turn, down-regulates Fli-1 expression and prevents granulocytic differentiation.

Gene Network Analysis of Glucose Linked Signaling Pathways and Their Role in Human Hepatocellular Carcinoma Cell Growth and Survival in HuH7 and HepG2 Cell Lines.

Cancer progression may be affected by metabolism. In this study, we aimed to analyze the effect of glucose on the proliferation and/or survival of human hepatocellular carcinoma (HCC) cells. Human gene datasets regulated by glucose were compared to gene datasets either dysregulated in HCC or regulated by other signaling pathways. Significant numbers of common genes suggested putative involvement in transcriptional regulations by glucose. Real-time proliferation assays using high (4.5 g/L) versus low (1 g/L) glucose on two human HCC cell lines and specific inhibitors of selected pathways were used for experimental validations. High glucose promoted HuH7 cell proliferation but not that of HepG2 cell line. Gene network analyses suggest that gene transcription by glucose could be mediated at 92% through ChREBP in HepG2 cells, compared to 40% in either other human cells or rodent healthy liver, with alteration of LKB1 (serine/threonine kinase 11) and NOX (NADPH oxidases) signaling pathways and loss of transcriptional regulation of PPARGC1A (peroxisome-proliferator activated receptors gamma coactivator 1) target genes by high glucose. Both PPARA and PPARGC1A regulate transcription of genes commonly regulated by glycolysis, by the antidiabetic agent metformin and by NOX, suggesting their major interplay in the control of HCC progression.

Antimicrobial peptides keep insect endosymbionts under control.

Vertically transmitted endosymbionts persist for millions of years in invertebrates and play an important role in animal evolution. However, the functional basis underlying the maintenance of these long-term resident bacteria is unknown. We report that the weevil coleoptericin-A (ColA) antimicrobial peptide selectively targets endosymbionts within the bacteriocytes and regulates their growth through the inhibition of cell division. Silencing the colA gene with RNA interference resulted in a decrease in size of the giant filamentous endosymbionts, which escaped from the bacteriocytes and spread into insect tissues. Although this family of peptides is commonly linked with microbe clearance, this work shows that endosymbiosis benefits from ColA, suggesting that long-term host-symbiont coevolution might have shaped immune effectors for symbiont maintenance.

Inducible Fli-1 gene deletion in adult mice modifies several myeloid lineage commitment decisions and accelerates proliferation arrest and terminal erythrocytic differentiation.

This study investigated the role of the ETS transcription factor Fli-1 in adult myelopoiesis using new transgenic mice allowing inducible Fli-1 gene deletion. Fli-1 deletion in adult induced mild thrombocytopenia associated with a drastic decrease in large mature megakaryocytes number. Bone marrow bipotent megakaryocytic-erythrocytic progenitors (MEPs) increased by 50% without increase in erythrocytic and megakaryocytic common myeloid progenitor progeny, suggesting increased production from upstream stem cells. These MEPs were almost unable to generate pure colonies containing large mature megakaryocytes, but generated the same total number of colonies mainly identifiable as erythroid colonies containing a reduced number of more differentiated cells. Cytological and fluorescence-activated cell sorting analyses of MEP progeny in semisolid and liquid cultures confirmed the drastic decrease in large mature megakaryocytes but revealed a surprisingly modest (50%) reduction of CD41-positive cells indicating the persistence of a megakaryocytic commitment potential. Symmetrical increase and decrease of monocytic and granulocytic progenitors were also observed in the progeny of purified granulocytic-monocytic progenitors and common myeloid progenitors. In summary, this study indicates that Fli-1 controls several lineages commitment decisions at the stem cell, MEP, and granulocytic-monocytic progenitor levels, stimulates the proliferation of committed erythrocytic progenitors at the expense of their differentiation, and is a major regulator of late stages of megakaryocytic differentiation.

A polyploid population of Saccharomyces cerevisiae with separate sexes (dioecy).

Saccharomyces cerevisiae has proved to be an interesting model for studies of evolution, with whole-genome duplication shown to have played an important role in the evolution of this species. This phenomenon depends on the formation of a transient stable polyploid state. Previous studies have reported polyploidy to be an unstable state in yeast, but here, we describe a polyploid population of S. cerevisiae. The evolution of higher eukaryotes has also involved the development of different systems of sexual reproduction, the choice between self-fertilization and out-crossing becoming a key issue. Saccharomyces cerevisiae is a hermaphrodite eukaryote, despite the theoretical genetic disadvantages of this strategy, in which self-fertilization occurs. We describe, for the first time, a near-dioecious (with separate sexes) population in this species. Mating type and the MAT locus display complex segregations. Essentially, each strain produces, by meiosis, spores of only one mating type: mata or matalpha. Moreover, strains are heterothallic, and diploid nonmating clones generated from a single spore do not sporulate. These three properties limit self-fertilization and strongly favour out-crossing. We suggest that the shift in sexual strategy, from hermaphroditism to dioecy, is specific to the brewing process, which overcomes the sexual isolation probably found in natural biotopes.