Omics technologies provide new insights into the molecular physiopathology of equine osteochondrosis

Background: Osteochondrosis (OC(D)) is a juvenile osteo-articular disorder affecting several mammalian species. In horses, OC(D) is considered as a multifactorial disease and has been described as a focal disruption of endochondral ossification leading to the development of osteoarticular lesions. Nevertheless, OC(D) physiopathology is poorly understood. Affected horses may present joint swelling, stiffness and lameness. Thus, OC(D) is a major concern for the equine industry. Our study was designed as an integrative approach using omics technologies for the identification of constitutive defects in epiphyseal cartilage and/or subchondral bone associated with the development of primary lesions to further understand OC(D) pathology. This study compared samples from non-affected joints (hence lesion-free) from OC(D)-affected foals (n = 5, considered predisposed samples) with samples from OC-free foals (n = 5) considered as control samples. Consequently, results are not confounded by changes associated with the evolution of the lesion, but focus on altered constitutive molecular mechanisms. Comparative proteomics and micro computed tomography analyses were performed on predisposed and OC-free bone and cartilage samples. Metabolomics was also performed on synovial fluid from OC-free, OC(D)-affected and predisposed joints. Results: Two lesion subtypes were identified: OCD (lesion with fragment) and OC (osteochondral defects). Modulated proteins were identified using omics technologies (2-DE proteomics) in cartilage and bone from affected foals compare to OC-free foals. These were associated with cellular processes including cell cycle, energy production, cell signaling and adhesion as well as tissue-specific processes such as chondrocyte maturation, extracellular matrix and mineral metabolism. Of these, five had already been identified in synovial fluid of OC-affected foals: ACTG1 (actin, gamma 1), albumin, haptoglobin, FBG (fibrinogen beta chain) and C4BPA (complement component 4 binding protein, alpha). Conclusion: This study suggests that OCD lesions may result from a cartilage defect whereas OC lesions may be triggered by both bone and cartilage defects, suggesting that different molecular mechanisms responsible for the equine osteochondrosis lesion subtypes and predisposition could be due to a defect in both bone and cartilage. This study will contribute to refining the definition of OC(D) lesions and may improve diagnosis and development of therapies for horses and other species, including humans

Molecular and physiopathological bases of horse susceptibility to osteochondrosis.

L'ostéochondrose (OC) est une affection ostéo-articulaire juvénile caractérisée par une perturbation locale de la maturation du cartilage créant des zones de fragilité. L'OC a été décrite chez de nombreuses espèces dont l'Homme, le Chien, le Porc, le Poulet et le Cheval. Chez le cheval les lésions s'installent progressivement, sans symptômes, avant l'âge d'un an et les manifestations cliniques ne se manifestent que tardivement, souvent à l'entraînement. L'OC affecte 10 à 30 % de la population équine représentant ainsi un souci majeur pour la filière tant sur le plan du bien être animal que sur le plan économique. Son étiologie, multifactorielle, est encore mal comprise et implique des composantes génétiques et environnementales ainsi que traumatiques. Les objectifs des travaux présentés étaient d'améliorer la compréhension de la physiopathologie de l'OC équine et de mettre en évidence les processus biologiques perturbés. L'ensemble des résultats a permis de préciser la définition des différentes entités de l'OC et pourraient également être pertinentes dans l'amélioration du diagnostic et le dévelopement de nouveaux traitements. Un défaut constitutif de l'os et du cartilage a été mis en évidence chez les individus atteints d'OC, notamment associé à une perturbation du métabolisme énergénique et un stress du reticulum endoplasmique. De plus, selon le type de lésions, des mécanismes moléculaires sous-jacents différents sont impliqués dans leur développement. D'autre part, les microARNs (miRNAs) semblent également jouer un rôle dans la physiopathologie de l'OC et certains d'entre eux pourraient constituer de bonnes cibles thérapeutiques ou être utilisés comme biomarqueurs diagnostics.Osteochondrosis (OC) is a juvenile osteo-articular disease characterized by a focal failure of cartilage maturation leading to weak areas. OC has been described in several species including Human, Dog, Swine, Poultry and Horse. In horse, lesions develop gradually without symptoms before one year old and clinical manifestations occur tardily during training. OC affects 10 to 30% of equine population and constitutes a major concern in terms of animal welfare and economy. Its multifactorial etiology remains poorly understood and involved several factors including genetics, environment and traumas. The aim of this current work was to improve the comprehension of equine OC physiopathology and highlight biological pathways disrupted. Taken together, our results made it possible to refine the definition of OC entities and our data could be relevant to improve diagnosis and develop new therapies. A constitutive defect was found in cartilage and bone of OC-affected horses and particularly a defective energy metabolism and a endoplasmic reticulum stress. Moreover, in function of lesion type, different underlying molecular mechanisms are involved in their development. Secondly, mircoRNAs (miRNAs) seem to take part in the OC physiopathology and some miRNAs could constitute a relevant therapeutic target or be used as diagnosis biomarkers

Molecular and physiopathological bases of horse susceptibility to osteochondrosis.

L'ostéochondrose (OC) est une affection ostéo-articulaire juvénile caractérisée par une perturbation locale de la maturation du cartilage créant des zones de fragilité. L'OC a été décrite chez de nombreuses espèces dont l'Homme, le Chien, le Porc, le Poulet et le Cheval. Chez le cheval les lésions s'installent progressivement, sans symptômes, avant l'âge d'un an et les manifestations cliniques ne se manifestent que tardivement, souvent à l'entraînement. L'OC affecte 10 à 30 % de la population équine représentant ainsi un souci majeur pour la filière tant sur le plan du bien être animal que sur le plan économique. Son étiologie, multifactorielle, est encore mal comprise et implique des composantes génétiques et environnementales ainsi que traumatiques. Les objectifs des travaux présentés étaient d'améliorer la compréhension de la physiopathologie de l'OC équine et de mettre en évidence les processus biologiques perturbés. L'ensemble des résultats a permis de préciser la définition des différentes entités de l'OC et pourraient également être pertinentes dans l'amélioration du diagnostic et le dévelopement de nouveaux traitements. Un défaut constitutif de l'os et du cartilage a été mis en évidence chez les individus atteints d'OC, notamment associé à une perturbation du métabolisme énergénique et un stress du reticulum endoplasmique. De plus, selon le type de lésions, des mécanismes moléculaires sous-jacents différents sont impliqués dans leur développement. D'autre part, les microARNs (miRNAs) semblent également jouer un rôle dans la physiopathologie de l'OC et certains d'entre eux pourraient constituer de bonnes cibles thérapeutiques ou être utilisés comme biomarqueurs diagnostics.Osteochondrosis (OC) is a juvenile osteo-articular disease characterized by a focal failure of cartilage maturation leading to weak areas. OC has been described in several species including Human, Dog, Swine, Poultry and Horse. In horse, lesions develop gradually without symptoms before one year old and clinical manifestations occur tardily during training. OC affects 10 to 30% of equine population and constitutes a major concern in terms of animal welfare and economy. Its multifactorial etiology remains poorly understood and involved several factors including genetics, environment and traumas. The aim of this current work was to improve the comprehension of equine OC physiopathology and highlight biological pathways disrupted. Taken together, our results made it possible to refine the definition of OC entities and our data could be relevant to improve diagnosis and develop new therapies. A constitutive defect was found in cartilage and bone of OC-affected horses and particularly a defective energy metabolism and a endoplasmic reticulum stress. Moreover, in function of lesion type, different underlying molecular mechanisms are involved in their development. Secondly, mircoRNAs (miRNAs) seem to take part in the OC physiopathology and some miRNAs could constitute a relevant therapeutic target or be used as diagnosis biomarkers

Bases moléculaires et physiopathologiques de l'ostéochondrose équine

Osteochondrosis (OC) is a juvenile osteo-articular disease characterized by a focal failure of cartilage maturation leading to weak areas. OC has been described in several species including Human, Dog, Swine, Poultry and Horse. In horse, lesions develop gradually without symptoms before one year old and clinical manifestations occur tardily during training. OC affects 10 to 30% of equine population and constitutes a major concern in terms of animal welfare and economy. Its multifactorial etiology remains poorly understood and involved several factors including genetics, environment and traumas. The aim of this current work was to improve the comprehension of equine OC physiopathology and highlight biological pathways disrupted. Taken together, our results made it possible to refine the definition of OC entities and our data could be relevant to improve diagnosis and develop new therapies. A constitutive defect was found in cartilage and bone of OC-affected horses and particularly a defective energy metabolism and a endoplasmic reticulum stress. Moreover, in function of lesion type, different underlying molecular mechanisms are involved in their development. Secondly, mircoRNAs (miRNAs) seem to take part in the OC physiopathology and some miRNAs could constitute a relevant therapeutic target or be used as diagnosis biomarkers.L'ostéochondrose (OC) est une affection ostéo-articulaire juvénile caractérisée par une perturbation locale de la maturation du cartilage créant des zones de fragilité. L'OC a été décrite chez de nombreuses espèces dont l'Homme, le Chien, le Porc, le Poulet et le Cheval. Chez le cheval les lésions s'installent progressivement, sans symptômes, avant l'âge d'un an et les manifestations cliniques ne se manifestent que tardivement, souvent à l'entraînement. L'OC affecte 10 à 30 % de la population équine représentant ainsi un souci majeur pour la filière tant sur le plan du bien être animal que sur le plan économique. Son étiologie, multifactorielle, est encore mal comprise et implique des composantes génétiques et environnementales ainsi que traumatiques. Les objectifs des travaux présentés étaient d'améliorer la compréhension de la physiopathologie de l'OC équine et de mettre en évidence les processus biologiques perturbés. L'ensemble des résultats a permis de préciser la définition des différentes entités de l'OC et pourraient également être pertinentes dans l'amélioration du diagnostic et le dévelopement de nouveaux traitements. Un défaut constitutif de l'os et du cartilage a été mis en évidence chez les individus atteints d'OC, notamment associé à une perturbation du métabolisme énergénique et un stress du reticulum endoplasmique. De plus, selon le type de lésions, des mécanismes moléculaires sous-jacents différents sont impliqués dans leur développement. D'autre part, les microARNs (miRNAs) semblent également jouer un rôle dans la physiopathologie de l'OC et certains d'entre eux pourraient constituer de bonnes cibles thérapeutiques ou être utilisés comme biomarqueurs diagnostics

“NiCo Buster”: engineering E. coli for fast and efficient capture of cobalt and nickel

BACKGROUND: Metal contamination is widespread and results from natural geogenic and constantly increasing anthropogenic sources (mainly mining and extraction activities, electroplating, battery and steel manufacturing or metal finishing). Consequently, there is a growing need for methods to detoxify polluted ecosystems. Industrial wastewater, surface water and ground water need to be decontaminated to alleviate the contamination of soils and sediments and, ultimately, the human food chain. In nuclear power plants, radioactive metals are produced; these metals need to be removed from effluents before they are released into the environment, not only for pollution prevention but also for waste minimization. Many physicochemical methods have been developed for metal removal from aqueous solutions, including chemical coagulation, adsorption, extraction, ion exchange and membrane separation; however, these methods are generally not metal selective. Bacteria, because they contain metal transporters, provide a potentially competitive alternative to the current use of expensive and high-volume ion-exchange resins. RESULTS: The feasibility of using bacterial biofilters as efficient tools for nickel and cobalt ions specific remediation was investigated. Among the factors susceptible to genetic modification in Escherichia coli, specific efflux and sequestration systems were engineered to improve its metal sequestration abilities. Genomic suppression of the RcnA nickel (Ni) and cobalt (Co) efflux system was combined with the plasmid-controlled expression of a genetically improved version of a specific metallic transporter, NiCoT, which originates from Novosphingobium aromaticivorans. The resulting strain exhibited enhanced nickel (II) and cobalt (II) uptake, with a maximum metal ion accumulation of 6 mg/g bacterial dry weight during 10 min of treatment. A synthetic adherence operon was successfully introduced into the plasmid carrying the improved NiCoT transporter, conferring the ability to form thick biofilm structures, especially when exposed to nickel and cobalt metallic compounds. CONCLUSIONS: This study demonstrates the efficient use of genetic engineering to increase metal sequestration and biofilm formation by E. coli. This method allows Co and Ni contaminants to be sequestered while spatially confining the bacteria to an abiotic support. Biofiltration of nickel (II) and cobalt (II) by immobilized cells is therefore a promising option for treating these contaminants at an industrial scale

Involvement of mitochondrial dysfunction and ER-stress in the physiopathology of equine osteochondritis dissecans (OCD).

International audience: Osteochondrosis (OC) is a developmental bone disorder affecting several mammalian species including the horse. Equine OC is described as a focal disruption of endochondral ossification, leading to osteochondral lesions (osteochondritis dissecans, OCD) that may release free bodies within the joint. OCD lesions trigger joint swelling, stiffness and lameness and affects about 30% of the equine population. OCD is considered as multifactorial but its physiopathology is still poorly understood and genes involved in genetic predisposition are still unknown. Our study compared two healthy and two OC-affected 18-month-old French Trotters diagnosed with OCD lesions at the intermediate ridge of the distal tibia. A comparative shot-gun proteomic analysis of non-wounded cartilage and sub-chondral bone from healthy (healthy samples) and OC-affected foals (predisposed samples) identified 83 and 53 modulated proteins, respectively. These proteins are involved in various biological pathways including matrix structure and maintenance, protein biosynthesis, folding and transport, mitochondrial activity, energy and calcium metabolism. Transmission electron microscopy revealed typical features of mitochondrial swelling and ER-stress, such as large, empty mitochondria, and hyper-dilated rough endoplasmic reticulum, in the deep zone of both OC lesions and predisposed cartilage. Abnormal fibril organization surrounding chondrocytes and abnormal features at the ossification front were also observed. Combining these findings with quantitative trait loci and whole genome sequencing results identified about 140 functional candidate genes carrying putative damaging mutations in 30 QTL regions. In summary, our study suggests that OCD lesions may result from defective hypertrophic terminal differentiation associated with mitochondrial dysfunction and ER-stress, leading to impaired cartilage and bone biomechanical properties, making them prone to fractures. In addition, 11 modulated proteins and several candidate mutations located in QTL regions were identified, bringing new insight into the molecular physiopathology and genetic basis of OCD

Chondrocytes Play a Major Role in the Stimulation of Bone Growth by Thyroid Hormone

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Monocyte-Derived Dendritic Cells (MDDCs) from Spondyloarthritis (SpA) Patients Exhbit a Coordinated Downregulation of the Cholesterol (chol) Biosynthesis Pathway That Relates to Lipid Overload

International audienceBackground/Purpose: Gene expression studies are useful to investigate the pathogenesis of complex diseases. The critical role of antigen-presenting cells such as dendritic cells (DCs) being suspected in SpA, we wished to study their particular biology, starting from unbiased transcriptomic experiment. Methods: MDDCs were obtained from circulating CD14+ monocytes after 7 days of culture with GMCSF + IL-4. Transcriptomes were profiled using Affymetrix microarrays (HuGene 1.0 ST) and further confirmed by RNA-seq (78 million paired-end reads (2×100 nt) per sample). Differentially expressed (DE) genes between SpA (ASAS criteria) and healthy controls (HC) were listed with LIMMA. Functional annotation was performed with DAVID and InnateDB. RT-qPCR was used to test the reproducibility of the signature over time. Intra-cellular lipid dropplets (LD) volume and number were quantified by Bodipy® labeling and confocal microscopy . Cellular content of chol pathway metabolites was quantified by mass spectrometry (MS). Results: For transcriptomic analysis, we generated 3 lists of DE genes (nominal p < 0.01) comparing (A) HLA-B27+ SpA (n=40) to B27-neg HC (n=30), (B) B27+ HC (n=44) to B27-neg HC and (C) B27+ SpA to B27+ HC. Subtraction A–B and intersection with C yielded a robust list of 68 genes affected by SpA controlling for unrelated HLA-B27 effect. Analysis of functional pathways revealed a significant overrepresentation of genes involved in chol biosynthesis and its regulation (p < 1×10-4). Five of the 6 genes in this pathway (SQLE, MSMO1, LDLR, INSIG1, SREBF2) were downregulated in SpA. These findings were confirmed by RNA-seq on the same samples and by qPCR on a new series of samples drawn from the same group of individuals (11 SpA vs. 10 HC). Using MS, we evidenced a significant increase of chol and 27-OH-chol content in MDDC from another panel of SpA (n = 14) compared to HC (n = 8) (p < 0.05), suggesting that downregulation of cholesterol synthesis might be secondary to chol overload. Consistently, there was a highly significant increase in the size (p = 5×10-4) and overall volume (p < 2×10-4) of LD in SpA (n=12) compared to HC (n=11) MDDCs (Figure). Importantly, there was no difference of total nor fractionated chol plasma levels between SpA and controls. Conclusion: Our study identified a downregulation of the chol synthesis pathway in MDDCs from SpA patients that seems to be secondary to lipid overload in those cells. Our findings are consistent with a state of pre-activation of those cells that could lead to a strong inflammatory response to endogenous or environmental stimuli

Monocyte-Derived Dendritic Cells (MDDCs) from Spondyloarthritis (SpA) Patients Exhbit a Coordinated Downregulation of the Cholesterol (chol) Biosynthesis Pathway That Relates to Lipid Overload

International audienceBackground/Purpose: Gene expression studies are useful to investigate the pathogenesis of complex diseases. The critical role of antigen-presenting cells such as dendritic cells (DCs) being suspected in SpA, we wished to study their particular biology, starting from unbiased transcriptomic experiment. Methods: MDDCs were obtained from circulating CD14+ monocytes after 7 days of culture with GMCSF + IL-4. Transcriptomes were profiled using Affymetrix microarrays (HuGene 1.0 ST) and further confirmed by RNA-seq (78 million paired-end reads (2×100 nt) per sample). Differentially expressed (DE) genes between SpA (ASAS criteria) and healthy controls (HC) were listed with LIMMA. Functional annotation was performed with DAVID and InnateDB. RT-qPCR was used to test the reproducibility of the signature over time. Intra-cellular lipid dropplets (LD) volume and number were quantified by Bodipy® labeling and confocal microscopy . Cellular content of chol pathway metabolites was quantified by mass spectrometry (MS). Results: For transcriptomic analysis, we generated 3 lists of DE genes (nominal p < 0.01) comparing (A) HLA-B27+ SpA (n=40) to B27-neg HC (n=30), (B) B27+ HC (n=44) to B27-neg HC and (C) B27+ SpA to B27+ HC. Subtraction A–B and intersection with C yielded a robust list of 68 genes affected by SpA controlling for unrelated HLA-B27 effect. Analysis of functional pathways revealed a significant overrepresentation of genes involved in chol biosynthesis and its regulation (p < 1×10-4). Five of the 6 genes in this pathway (SQLE, MSMO1, LDLR, INSIG1, SREBF2) were downregulated in SpA. These findings were confirmed by RNA-seq on the same samples and by qPCR on a new series of samples drawn from the same group of individuals (11 SpA vs. 10 HC). Using MS, we evidenced a significant increase of chol and 27-OH-chol content in MDDC from another panel of SpA (n = 14) compared to HC (n = 8) (p < 0.05), suggesting that downregulation of cholesterol synthesis might be secondary to chol overload. Consistently, there was a highly significant increase in the size (p = 5×10-4) and overall volume (p < 2×10-4) of LD in SpA (n=12) compared to HC (n=11) MDDCs (Figure). Importantly, there was no difference of total nor fractionated chol plasma levels between SpA and controls. Conclusion: Our study identified a downregulation of the chol synthesis pathway in MDDCs from SpA patients that seems to be secondary to lipid overload in those cells. Our findings are consistent with a state of pre-activation of those cells that could lead to a strong inflammatory response to endogenous or environmental stimuli