A gait functional classification of adolescent idiopathic scoliosis (AIS) based on spatio-temporal parameters (STP).

BACKGROUND: Therapeutic decisions for patients with adolescent idiopathic scoliosis (AIS) are mostly based on static measurements performed on two-dimensional standing full-spine radiographs. However, the trunk plays an essential role in the human locomotion, and the functional consequences during daily activities of this specific and common spinal deformity are not factored in. RESEARCH QUESTION: Does patients with AIS have specific gait patterns based on spatio-temporals parameters measurements ? METHODS: 90 AIS patients (aged 10-18 years) with preoperative simplified gait analysis were retrospectively included for analysis between 2017 and 2020. Spatio-temporal parameters (STP) were measured on a 3-m baropodometric gaitway and included the measurement of 15 normalized gait parameters. A hierarchical cluster analysis was performed to identify group of patients based on the similarities of their gait patterns, and functional variables' inter-group differences were also measured. The subject distribution was calculated to identify the structural characteristics of the subjects according to their gait patterns. RESULTS: Three gait patterns were identified. Cluster 1 (46%) was defined by asymmetry, Cluster 2 (16%) by instability, and Cluster 3 (36%) by variability. Each cluster was significantly different from the other ones on at least 6 different parameters (p < 0.05). Furthermore, each cluster was associated with one type of curve: Lenke 1 for Cluster 1 (57.5%), Lenke 6 for Cluster 2 (40%) and Lenke 5 for Cluster 3 (43.5%). SIGNIFICANCE: Patients with severe AIS have a dynamic signature during gait identified on STP. Understanding consequences of this deformity on gait may be an interesting avenue to study the pathological mechanisms involved in their dynamic motor organization. Furthermore, these results might also be a first step to study the effectiveness of the different therapies.

Linking chemicals, genes and morphological perturbations to diseases.

The progress in image-based high-content screening technology has facilitated high-throughput phenotypic profiling notably the quantification of cell morphology perturbation by chemicals. However, understanding the mechanism of action of a chemical and linking it to cell morphology and phenotypes remains a challenge in drug discovery. In this study, we intended to integrate molecules that induced transcriptomic perturbations and cellular morphological changes into a biological network in order to assess chemical-phenotypic relationships in humans. Such a network was enriched with existing disease information to suggest molecular and cellular profiles leading to phenotypes. Two datasets were used for this study. Firstly, we used the "Cell Painting morphological profiling assay" dataset, composed of 30,000 compounds tested on human osteosarcoma cells (named U2OS). Secondly, we used the "L1000 mRNA profiling assay" dataset, a collection of transcriptional expression data from cultured human cells treated with approximately 20,000 bioactive small molecules from the Library of Integrated Network-based Cellular Signatures (LINCS). Furthermore, pathways, gene ontology terms and disease enrichments were performed on the transcriptomics data. Overall, our study makes it possible to develop a biological network combining chemical-gene-pathway-morphological perturbation and disease relationships. It contains an ensemble of 9989 chemicals, 732 significant morphological features and 12,328 genes. Through diverse examples, we demonstrated that some drugs shared similar genes, pathways and morphological profiles that, taken together, could help in deciphering chemical-phenotype observations.

Lung Antioxidant Depletion: A Predictive Indicator of Cellular Stress Induced by Ambient Fine Particles.

Regulations on ambient particulate matter (PM) are becoming more stringent because of adverse health effects arising from PM exposure. PM-induced oxidant production is a key mechanism behind the observed health effects and is heavily dependent on PM composition. Measurement of the intrinsic oxidative potential (OP) of PM could provide an integrated indicator of PM bioreactivity and could serve as a better metric of PM hazard exposure than PM mass concentration. The OP of two chemically contrasted PM2.5 samples was compared through four acellular assays, and OP predictive capability was evaluated in different cellular assays on two in vitro lung cell models. PM2.5 collected in Paris at a site close to the traffic exhibited a systematically higher OP in all assays compared to PM2.5 enriched in particles from domestic wood burning. Similar results were obtained for oxidative stress, expression of antioxidant enzymes, and pro-inflammatory chemokine in human bronchial epithelial and endothelial cells. The strongest correlations between OP assays and cellular responses were observed with the antioxidant (ascorbic acid and glutathione) depletion (OPAO) assay. Multivariate regression analysis from OP daily measurements suggested that OPAO was strongly correlated with polycyclic aromatic hydrocarbons at the traffic site while it was correlated with potassium for the domestic wood burning sample.

High Impact: The Role of Promiscuous Binding Sites in Polypharmacology.

The literature focuses on drug promiscuity, which is a drug's ability to bind to several targets, because it plays an essential role in polypharmacology. However, little work has been completed regarding binding site promiscuity, even though its properties are now recognized among the key factors that impact drug promiscuity. Here, we quantified and characterized the promiscuity of druggable binding sites from protein-ligand complexes in the high quality Mother Of All Databases while using statistical methods. Most of the sites (80%) exhibited promiscuity, irrespective of the protein class. Nearly half were highly promiscuous and able to interact with various types of ligands. The corresponding pockets were rather large and hydrophobic, with high sulfur atom and aliphatic residue frequencies, but few side chain atoms. Consequently, their interacting ligands can be large, rigid, and weakly hydrophilic. The selective sites that interacted with one ligand type presented less favorable pocket properties for establishing ligand contacts. Thus, their ligands were highly adaptable, small, and hydrophilic. In the dataset, the promiscuity of the site rather than the drug mainly explains the multiple interactions between the drug and target, as most ligand types are dedicated to one site. This underlines the essential contribution of binding site promiscuity to drug promiscuity between different protein classes.

Synthetic lethals in HIV: ways to avoid drug resistance : Running title: Preventing HIV resistance.

BACKGROUND: RNA viruses rapidly accumulate genetic variation, which can give rise to synthetic lethal (SL) and deleterious (SD) mutations. Synthetic lethal mutations (non-lethal when alone but lethal when combined in one genome) have been studied to develop cancer therapies. This principle can also be used against fast-evolving RNA-viruses. Indeed, targeting protein sites involved in SD + SL interactions with a drug would render any mutation of such sites, lethal. RESULTS: Here, we set up a strategy to detect intragenic pairs of SL and SD at the surface of the protein to predict less escapable drug target sites. For this, we detected SD + SL, studying HIV protease (PR) and reverse transcriptase (RT) sequence alignments from two groups of VIH(+) individuals: treated with drugs (T) or not (NT). Using a series of statistical approaches, we were able to propose bona fide SD + SL couples. When focusing on spatially close co-variant SD + SL couples at the surface of the protein, we found 5 SD + SL groups (2 in the protease and 3 in the reverse transcriptase), which could be good candidates to form pockets to accommodate potential drugs. CONCLUSIONS: Thus, designing drugs targeting these specific SD + SL groups would not allow the virus to mutate any residue involved in such groups without losing an essential function. Moreover, we also show that the selection pressure induced by the treatment leads to the appearance of new mutations, which change the mutational landscape of the protein. This drives the existence of differential SD + SL couples between the drug-treated and non-treated groups. Thus, new anti-viral drugs should be designed differently to target such groups.

Excitation/inhibition balance and learning are modified by Dyrk1a gene dosage.

Cognitive deficits in Down syndrome (DS) have been linked to increased synaptic inhibition, leading to an imbalance of excitation/inhibition (E/I). Various mouse models and studies from human brains have implicated an HSA21 gene, the serine/threonine kinase DYRK1A, as a candidate for inducing cognitive dysfunction. Here, consequences of alterations in Dyrk1a dosage were assessed in mouse models with varying copy numbers of Dyrk1a: mBACtgDyrk1a, Ts65Dn and Dp(16)1Yey (with 3 gene copies) and Dyrk1a(+/-) (one functional copy). Molecular (i.e. immunoblotting/immunohistochemistry) and behavioral analyses (e.g., rotarod, Morris water maze, Y-maze) were performed in mBACtgDyrk1a mice. Increased expression of DYRK1A in mBACtgDyrk1a induced molecular alterations in synaptic plasticity pathways, particularly expression changes in GABAergic and glutaminergic related proteins. Similar alterations were observed in models with partial trisomy of MMU16, Ts65Dn and Dp(16)1Yey, and were reversed in the Dyrk1a(+/-) model. Dyrk1a overexpression produced an increased number and signal intensity of GAD67 positive neurons, indicating enhanced inhibition pathways in three different models: mBACtgDyrk1a, hYACtgDyrk1a and Dp(16)1Yey. Functionally, Dyrk1a overexpression protected mice from PTZ-induced seizures related to GABAergic neuron plasticity. Our study shows that DYRK1A overexpression affects pathways involved in synaptogenesis and synaptic plasticity and influences E/I balance toward inhibition. Inhibition of DYRK1A activity offers a therapeutic target for DS, but its inhibition/activation may also be relevant for other psychiatric diseases with E/I balance alterations.

Physico-chemical characterization of African urban aerosols (Bamako in Mali and Dakar in Senegal) and their toxic effects in human bronchial epithelial cells: description of a worrying situation.

BACKGROUND: The involvement of particulate matter (PM) in cardiorespiratory diseases is now established in developed countries whereas in developing areas such as Africa with a high level of specific pollution, PM pollution and its effects are poorly studied. Our objective was to characterize the biological reactivity of urban African aerosols on human bronchial epithelial cells in relation to PM physico-chemical properties to identify toxic sources. METHODS: Size-speciated aerosol chemical composition was analyzed in Bamako (BK, Mali, 2 samples with one having desert dust event BK1) and Dakar (DK; Senegal) for Ultrafine UF, Fine F and Coarse C PM. PM reactivity was studied in human bronchial epithelial cells investigating six biomarkers (oxidative stress responsive genes and pro-inflammatory cytokines). RESULTS: PM mass concentrations were mainly distributed in coarse mode (60%) and were impressive in BK1 due to the desert dust event. BK2 and DK samples showed a high content of total carbon characteristic of urban areas. The DK sample had huge PAH quantities in bulk aerosol compared with BK that had more water soluble organic carbon and metals. Whatever the site, UF and F PM triggered the mRNA expression of the different biomarkers whereas coarse PM had little or no effect. The GM-CSF biomarker was the most discriminating and showed the strongest pro-inflammatory effect of BK2 PM. The analysis of gene expression signature and of their correlation with main PM compounds revealed that PM-induced responses are mainly related to organic compounds. The toxicity of African aerosols is carried by the finest PM as with Parisian aerosols, but when considering PM mass concentrations, the African population is more highly exposed to toxic particulate pollution than French population. Regarding the prevailing sources in each site, aerosol biological impacts are higher for incomplete combustion sources resulting from two-wheel vehicles and domestic fires than from diesel vehicles (Dakar). Desert dust events seem to produce fewer biological impacts than anthropogenic sources. DISCUSSION: Our study shows that combustion sources contribute to the high toxicity of F and UF PM of African urban aerosols, and underlines the importance of emission mitigation and the imperative need to evaluate and to regulate particulate pollution in Africa.

BDNF and DYRK1A are variable and inversely correlated in lymphoblastoid cell lines from Down syndrome patients.

Down syndrome or trisomy 21 is the most common genetic disorder leading to mental retardation. One feature is impaired short- and long-term spatial memory, which has been linked to altered brain-derived neurotrophic factor (BDNF) levels. Mouse models of Down syndrome have been used to assess neurotrophin levels, and reduced BDNF has been demonstrated in brains of adult transgenic mice overexpressing Dyrk1a, a candidate gene for Down syndrome phenotypes. Given the link between DYRK1A overexpression and BDNF reduction in mice, we sought to assess a similar association in humans with Down syndrome. To determine the effect of DYRK1A overexpression on BDNF in the genomic context of both complete trisomy 21 and partial trisomy 21, we used lymphoblastoid cell lines from patients with complete aneuploidy of human chromosome 21 (three copies of DYRK1A) and from patients with partial aneuploidy having either two or three copies of DYRK1A. Decreased BDNF levels were found in lymphoblastoid cell lines from individuals with complete aneuploidy as well as those with partial aneuploidies conferring three DYRK1A alleles. In contrast, lymphoblastoid cell lines from individuals with partial trisomy 21 having only two DYRK1A copies displayed increased BDNF levels. A negative correlation was also detected between BDNF and DYRK1A levels in lymphoblastoid cell lines with complete aneuploidy of human chromosome 21. This finding indicates an upward regulatory role of DYRK1A expression on BDNF levels in lymphoblastoid cell lines and emphasizes the role of genetic variants associated with psychiatric disorders.

Modulation of soleus H reflex by spinal DC stimulation in humans.

Transcranial direct current stimulation (tDCS) of the human motor cortex induces changes in excitability within cortical and spinal circuits that occur during and after the stimulation. Recently, transcutaneous spinal direct current stimulation (tsDCS) has been shown to modulate spinal conduction properties, as assessed by somatosensory-evoked potentials, and transynaptic properties of the spinal neurons, as tested by postactivation depression of the H reflex or by the RIII nociceptive component of the flexion reflex in the lower limb. To further explore tsDCS-induced plastic changes in spinal excitability, we examined, in a double-blind crossover randomized study, the stimulus-response curves of the soleus H reflex before, during, at current offset and 15 min after anodal, cathodal, and sham tsDCS delivered at the Th11 level (2.5 mA, 15 min, 0.071 mA/cm(2), 0.064 C/cm(2)) in 17 healthy subjects. Anodal tsDCS induced a progressive leftward shift of the recruitment curve of the soleus H reflex during the stimulation; the effects persisted for at least 15 min after current offset. In contrast, both cathodal and sham tsDCS had no significant effects. This exploratory study provides further evidence for the use of tsDCS as an expedient, noninvasive tool to induce long-lasting plastic changes in spinal circuitry. Increased spinal excitability after anodal tsDCS may have potential for spinal neuromodulation in patients with central nervous system lesions.

Noninvasive in vivo liver fibrosis evaluation using supersonic shear imaging: a clinical study on 113 hepatitis C virus patients.

Supersonic shear imaging (SSI) has recently been demonstrated to be a repeatable and reproducible transient bidimensional elastography technique. We report a prospective clinical evaluation of the performances of SSI for liver fibrosis evaluation in 113 patients with hepatitis C virus (HCV) and a comparison with FibroScan (FS). Liver elasticity values using SSI and FS ranged from 4.50 kPa to 33.96 kPa and from 2.60 kPa to 46.50 kPa, respectively. Analysis of variance (ANOVA) shows a good agreement between fibrosis staging and elasticity assessment using SSI and FS (p < 10(-5)). The areas under receiver operating characteristic (ROC) curves for elasticity values assessed from SSI were 0.948, 0.962 and 0.968 for patients with predicted fibrosis levels F ≥ 2, F ≥ 3 and F = 4, respectively. These values are compared with FS area under the receiver operating characteristic curve (AUROC) of 0.846, 0.857 and 0.940, respectively. This comparison between ROC curves is particularly significant for mild and intermediate fibrosis levels. SSI appears to be a fast, simple and reliable method for noninvasive liver fibrosis evaluation.

Exploring NMR ensembles of calcium binding proteins: perspectives to design inhibitors of protein-protein interactions.

BACKGROUND: Disrupting protein-protein interactions by small organic molecules is nowadays a promising strategy employed to block protein targets involved in different pathologies. However, structural changes occurring at the binding interfaces make difficult drug discovery processes using structure-based drug design/virtual screening approaches. Here we focused on two homologous calcium binding proteins, calmodulin and human centrin 2, involved in different cellular functions via protein-protein interactions, and known to undergo important conformational changes upon ligand binding. RESULTS: In order to find suitable protein conformations of calmodulin and centrin for further structure-based drug design/virtual screening, we performed in silico structural/energetic analysis and molecular docking of terphenyl (a mimicking alpha-helical molecule known to inhibit protein-protein interactions of calmodulin) into X-ray and NMR ensembles of calmodulin and centrin. We employed several scoring methods in order to find the best protein conformations. Our results show that docking on NMR structures of calmodulin and centrin can be very helpful to take into account conformational changes occurring at protein-protein interfaces. CONCLUSIONS: NMR structures of protein-protein complexes nowadays available could efficiently be exploited for further structure-based drug design/virtual screening processes employed to design small molecule inhibitors of protein-protein interactions.

DYRK1A, a novel determinant of the methionine-homocysteine cycle in different mouse models overexpressing this Down-syndrome-associated kinase.

BACKGROUND: Hyperhomocysteinemia, characterized by increased plasma homocysteine level, is associated with an increased risk of atherosclerosis. On the contrary, patients with Down syndrome appear to be protected from the development of atherosclerosis. We previously found a deleterious effect of hyperhomocysteinemia on expression of DYRK1A, a Down-syndrome-associated kinase. As increased expression of DYRK1A and low plasma homocysteine level have been associated with Down syndrome, we aimed to analyze the effect of its over-expression on homocysteine metabolism in mice. METHODOLOGY/PRINCIPAL FINDINGS: Effects of DYRK1A over-expression were examined by biochemical analysis of methionine metabolites, real-time quantitative reverse-transcription polymerase chain reaction, and enzyme activities. We found that over-expression of Dyrk1a increased the hepatic NAD(P)H:quinone oxidoreductase and S-adenosylhomocysteine hydrolase activities, concomitant with decreased level of plasma homocysteine in three mice models overexpressing Dyrk1a. Moreover, these effects were abolished by treatment with harmine, the most potent and specific inhibitor of Dyrk1a. The increased NAD(P)H:quinone oxidoreductase and S-adenosylhomocysteine hydrolase activities were also found in lymphoblastoid cell lines from patients with Down syndrome. CONCLUSIONS/SIGNIFICANCE: Our results might give clues to understand the protective effect of Down syndrome against vascular defect through a decrease of homocysteine level by DYRK1A over-expression. They reveal a link between the Dyrk1a signaling pathway and the homocysteine cycle.