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Abstract Background and methods The Zéro allergie research clinic (Saguenay, Canada) is a clinical and research initiative in oral immunotherapy (OIT) for managing IgE-mediated food allergy (FA). A total of 183 children with FA and 27 non-allergic siblings were recruited to date in the Zéro allergie cohort (ZAC) to better understand biological mechanisms underlying FA and OIT prognosis. The primary aims are to (a) better understand the genetic, epigenetic, transcriptomic, metabolomic, and microbial diversity associated with FA; (b) establish the multi-omics and microbial diversity profiles of children following OIT to identify predictive prognosis biomarkers, (c) make OIT more accessible to the population of the Saguenay–Lac-Saint-Jean region, and (d) build a biobank of data and biological material. Results The ZAC constitutes a unique and rich biobank of biological samples (blood, buccal swabs, microbiota samples [intestinal, buccal, nasal, and cutaneous]) combined with clinical data and more than 75 phenotypic characteristics. Conclusions This represents an innovative interdisciplinary initiative by researchers, allergists, and paediatricians to make FA care accessible to a greater number of children with IgE-mediated FA. Ultimately, it will contribute to provide more accessible treatment options with greater chances of success through a better understanding of the biological nature of FA and OIT.

Abstract Asthma affects 340 million people worldwide and varies in time. Twenty years ago, in Canada, the Saguenay–Lac-Saint-Jean asthma family cohort was created to study the genetic and environmental components of asthma. This study is a follow-up of 125 participants of this cohort to explore the appearance, persistence, and progression of asthma over 10–20 years. Participants answered a clinical standardized questionnaire. Lung function was assessed (forced expiratory volume in 1 s, forced vital capacity, bronchial reversibility, and methacholine bronchoprovocation), skin allergy testing was performed, blood samples were obtained (immunoglobulin E, white blood cell counts) and phenotypes were compared between recruitment and follow-up. From the participants without asthma at recruitment, 12% developed a phenotype of adult-onset asthma with the presence of risk factors, such as atopy, high body mass index, and exposure to smoking. A decrease of PC20 values in this group was observed and a decrease in the FEV1/FVC ratio in all groups. Also, 7% of individuals with asthma at recruitment developed chronic obstructive pulmonary disease, presenting risk factors at recruitment, such as moderate-to-severe bronchial hyperresponsiveness, exposure to smoking, and asthma. This study allowed a better interpretation of the evolution of asthma. Fine phenotypic characterization is the first step for meaningful genetic and epigenetic studies.

ABSTRACT Interactions between different bacterial species shape bacterial communities and their environments. The opportunistic pathogens Pseudomonas aeruginosa and Burkholderia cenocepacia both can colonize the lungs of individuals affected by cystic fibrosis. Using the social surface behavior called swarming motility as a study model, we noticed intricate interactions between B. cenocepacia K56-2 and P. aeruginosa PA14. While strain K56-2 does not swarm under P. aeruginosa favorable swarming conditions, co-inoculation with a nonmotile PA14 flagellum-less ΔfliC mutant restored spreading for both strains. We show that P. aeruginosa provides the wetting agent rhamnolipids allowing K56-2 to perform swarming motility, while aflagellated PA14 appears to “hitchhike” along with K56-2 cells in the swarming colony. IMPORTANCE Pseudomonas aeruginosa and Burkholderia cenocepacia are important opportunistic pathogens often found together in the airways of persons with cystic fibrosis. Laboratory cocultures of both species often ends with one taking over the other. We used a surface motility assay to study the social interactions between populations of these bacterial species. Under our conditions, B. cenocepacia cannot swarm without supplementation of the wetting agent produced by P. aeruginosa. In a mixed colony of both species, an aflagellated mutant of P. aeruginosa provides the necessary wetting agent to B. cenocepacia, allowing both bacteria to swarm and colonize a surface. We highlight this peculiar interaction where both bacteria set aside their antagonistic tendencies to travel together.

More than 107 pathogenic variations were identified in Keratin 14 gene (KRT14) in patients affected by epidermolysis bullosa simplex (EBS), a rare skin disease with still no curative treatment. Disease models as human induced pluripotent stem cells (hiPSCs) are promising tool for further advance the knowledge about this disorder and accelerate therapies development. Here, two hiPSC lines were reprogrammed from skin fibroblasts of two EBS patients carrying mutations within KRT14 by using CytoTune®Sendai virus. These iPSCs display pluripotent cell morphology, pluripotent markers expression, and the capability to differentiate into the three germ layers.

Heterozygous mutations within Keratin 5 (KRT5) are common genetic causes of epidermolysis bullosa simplex (EBS), a skin fragility disorder characterized by blisters, which appear after minor trauma. Using CytoTune®Sendai virus, we generated three human induced pluripotent stem cell (iPSC) lines from three EBS patients carrying respectively the single heterozygous mutations in KRT5, c.449 T > C, c.980 T > C, and c.608 T > C. All lines display normal karyotype, expressed high levels of pluripotent markers, and can differentiate into derivatives of the three germ layers. These iPSCs are helpful for a better understanding of the EBS pathogenesis and developing novel therapeutic approaches.

As a result of a founder effect, a Leigh syndrome variant called Leigh syndrome, French-Canadian type (LSFC, MIM / 220,111) is more frequent in Saguenay–Lac-Saint-Jean (SLSJ), a geographically isolated region on northeastern Quebec, Canada. LSFC is a rare autosomal recessive mitochondrial neurodegenerative disorder due to damage in mitochondrial energy production. LSFC is caused by pathogenic variants in the nuclear gene leucine-rich pentatricopeptide repeat-containing (LRPPRC). Despite progress understanding the molecular mode of action of LRPPRC gene, there is no treatment for this disease.The present study aims to identify the biological pathways altered in the LSFC disorder through microarray-based transcriptomic profile analysis of twelve LSFC cell lines compared to twelve healthy ones, followed by gene ontology (GO) and pathway analyses.A set of 84 significantly differentially expressed genes were obtained (p ≥ 0.05; Fold change (Flc) ≥ 1.5). 45 genes were more expressed (53.57%) in LSFC cell lines compared to controls and 39 (46.43%) had lower expression levels. Gene ontology analysis highlighted altered expression of genes involved in the mitochondrial respiratory chain and energy production, glucose and lipids metabolism, oncogenesis, inflammation and immune response, cell growth and apoptosis, transcription, and signal transduction. Considering the metabolic nature of LSFC disease, genes included in the mitochondrial respiratory chain and energy production cluster stood out as the most important ones to be involved in LSFC mitochondrial disorder. In addition, the protein-protein interaction network indicated a strong interaction between the genes included in this cluster. The mitochondrial gene NDUFA4L2 (NADH dehydrogenase [ubiquinone] 1 alpha subcomplex, 4-like 2), with higher expression in LSFC cells, represents a target for functional studies to explain the role of this gene in LSFC disease.This work provides, for the first time, the LSFC gene expression profile in fibroblasts isolated from affected individuals. This represents a valuable resource to understand the pathogenic basis and consequences of LRPPRC dysfunction.

Leigh Syndrome French Canadian (LSFC) is a rare autosomal recessive metabolic disorder characterized by severe lactic acidosis crises and early mortality. LSFC patients carry mutations in the Leucine Rich Pentatricopeptide Repeat Containing (LRPPRC) gene, which lead to defects in the respiratory chain complexes and mitochondrial dysfunction. Mitochondrial respiration modulates cellular metabolic activity, which impacts many cell types including the differentiation and function of immune cells. Hence, we postulated that, in addition to neurological and metabolic disorders, LSFC patients may show impaired immune activity. To gain insight into the quality of the immune response in LSFC patients, we examined the response to the measles, mumps and rubella (MMR) vaccine by measuring antibody titers to MMR in the plasma. In a cohort of eight LSFC patients, the response to the MMR vaccine was variable, with some individuals showing antibodies to all three viruses, while others had antibodies to two or fewer viruses. These results suggest that the mutations in the LRPPRC gene present in LSFC patients may affect the immune response to vaccines. Monitoring vaccine response in this fragile population should be considered to ensure full protection against pathogens.

Abstract Background This study reports the genetic features of four Caucasian males from the Saguenay‒Lac‐St‐Jean region affected by partial agenesis of the corpus callosum (ACC) with hypotonia, epilepsy, developmental delay, microcephaly, hypoplasia, and autistic behavior. Methods We performed whole exome sequencing (WES) to identify new genes involved in this pathological phenotype. The regions of interest were subsequently sequenced for family members. Results Single‐nucleotide variations (SNVs) and insertions or deletions were detected in genes potentially implicated in brain defects observed in these patients. One patient did not have mutations in genes related to ACC, but carried a de novo pathogenic mutation in Mucolipin‐1 (MCOLN1) and was diagnosed with mucolipidosis type IV. Among the other probands, missense SNVs were observed in DCLK2 (Doublecortin Like Kinase 2), HERC2 (HECT And RLD Domain Containing E3 Ubiquitin Protein Ligase 2), and KCNH3 (Potassium channel, voltage‐gated, subfamily H, member 3). One patient also carried a non‐frameshift insertion in CACNA1A (Cav2.1(P/Q‐type) calcium channels). Conclusion Although no common genetic defect was observed in this study, we provide evidence for new avenues of investigation for ACC, such as molecular pathways involving HERC2, CACNA1A, KCNH3, and more importantly DCLK2. We also allowed to diagnose an individual with mucolipidosis type IV.

Abstract Background Primary care patients are often cited as a cause of Emergency Department overcrowding (ED). The aim of this study was to evaluate a physician led redirection procedure of selected patients towards an out of hours general practice (OHGP) in an Emergency Department with 55,000 admissions per year. Methods Observational monocentric study over a period of 2 months. Every patient redirected to the OHGP was included and subsequently contacted by telephone to answer a standardized questionnaire, in order to measure:Redirection rate over the entire period and during weekdays or weekends/holidayRate of redirected patients who went to the OHGPRate of redirected patients who consulted in an ED in the next 72 h for the same reasonRedirected patients’ satisfaction rate Results During the study period 9551 patients presented to the ED, of which 288 were redirected towards the OHGP (3%). The redirection rate was 1.9% during weekdays and 5.7% during weekends/holiday (p

A decline in mitochondrial respiration represents the root cause of a large number of inborn errors of metabolism. It is also associated with common age-associated diseases and the aging process. To gain insight into the systemic, biochemical consequences of respiratory chain dysfunction, we performed a case-control, prospective metabolic profiling study in a genetically homogenous cohort of patients with Leigh syndrome French Canadian variant, a mitochondrial respiratory chain disease due to loss-of-function mutations in LRPPRC. We discovered 45 plasma and urinary analytes discriminating patients from controls, including classic markers of mitochondrial metabolic dysfunction (lactate and acylcarnitines), as well as unexpected markers of cardiometabolic risk (insulin and adiponectin), amino acid catabolism linked to NADH status (α-hydroxybutyrate), and NAD+ biosynthesis (kynurenine and 3-hydroxyanthranilic acid). Our study identifies systemic, metabolic pathway derangements that can lie downstream of primary mitochondrial lesions, with implications for understanding how the organelle contributes to rare and common diseases.

Mutations in LRPPRC are responsible for the French Canadian variant of Leigh Syndrome (LSFC), a severe disorder characterized biochemically by a tissue-specific deficiency of cytochrome c oxidase (COX) and clinically by the occurrence of severe and deadly acidotic crises. Factors that precipitate these crises remain unclear. To better understand the physiopathology and identify potential treatments, we performed a comprehensive analysis of mitochondrial function in LSFC and control fibroblasts. Furthermore, we have used this cell-based model to screen for conditions that promote premature cell death in LSFC cells and test the protective effect of ten interventions targeting well-defined aspects of mitochondrial function. We show that, despite maintaining normal ATP levels, LSFC fibroblasts present several mitochondrial functional abnormalities under normal baseline conditions, which likely impair their capacity to respond to stress. This includes mitochondrial network fragmentation, impaired oxidative phosphorylation capacity, lower membrane potential, increased sensitivity to Ca2+-induced permeability transition, but no changes in reactive oxygen species production. We also show that LSFC fibroblasts display enhanced susceptibility to cell death when exposed to palmitate, an effect that is potentiated by high lactate, while high glucose or acidosis alone or in combination were neutral. Furthermore, we demonstrate that compounds that are known to promote flux through the electron transport chain independent of phosphorylation (methylene blue, dinitrophenol), or modulate fatty acid (L-carnitine) or Krebs cycle metabolism (propionate) are protective, while antioxidants (idebenone, N-acetyl cysteine, resveratrol) exacerbate palmitate plus lactate-induced cell death. Collectively, beyond highlighting multiple alterations in mitochondrial function and increased susceptibility to nutrient-induced cytotoxicity in LSFC fibroblasts, these results raise questions about the nature of the diets, particularly excess fat intake, as well as on the use of antioxidants in patients with LSFC and, possibly, other COX defects.

Abstract - Leigh syndrome French Canadian (LSFC) is a recessive disease caused by mutations in the LRPPRC gene (leucine-rich pentatricopeptide repeat containing protein). These mutations induce a cytochrome c oxidase (COX) deficiency resulting in episodes of acute acidotic crisis that will often lead to death. There is no effective treatment. Methylene blue (MB) is a redox dye that increases COX content and activity in vitro and in vivo suggesting that MB could prevent and treat LSFC. In this study, the protective effect of low-concentration MB was tested on two LSFC cell lines, including LSFC-F1, homozygous for the mutation A354V, and LSFC-F2 a compound heterozygous for the mutations A354V and C12775STOP. MB effect on metabolic activity was assessed on both LSFC cells in stable and acidotic conditions. For LSFC-F1, results showed that metabolic activity drastically decline after 96 hours in both conditions but not LSFC-F2 and normal cells. MB completely prevents the decrease of metabolic activity in LSFC-F1. Intracellular ATP content was also measured in both culture media. After 96 hours in acidotic medium, ATP content was almost completely depleted for both LSFC cells. Interestingly, MB completely restores ATP content in LSFC-F1 and LSFC-F2 cells. Finally, MB strongly improves the survival of both LSFC cells. This article is open to POST-PUBLICATION REVIEW. Registered readers (see “For Readers”) may comment by clicking on ABSTRACT on the issue’s contents page.

Abstract Aliphatic diols such as ethylene and propylene glycol are the key products in the chemical industry for manufacturing polymers. The synthesis of these molecules usually implies sequential processes, including epoxidation of olefins using hydrogen peroxide or oxygen with subsequent hydrolysis to glycols. Direct hydroxylation of olefins by cheap and green oxidants is an economically attractive and environmentally friendly route for the synthesis of diols. Here, we report a photocatalytic reaction for the dihydroxylation of ethylene and propylene to their glycols at room temperature using water as the oxidant. The photocatalyst contains Pd clusters stabilized by sub-nanometric polyoxometalate with TiO2 as the host material. Under light irradiation, it results in production rates of ethylene glycol and propylene glycols of 146.8 mmol·gPd −1·h−1 and 28.6 mmol·gPd −1·h−1 with liquid-phase selectivities of 63.3 % and 80.0 %, respectively. Meanwhile, green hydrogen derived from water is produced as another valuable product. Combined spectroscopy investigation suggests that the reaction proceeds via π-bonded adsorption of olefins over Pd clusters with hydroxylation by hydroxyl radicals formed by photocatalytic dissociation of water.