Disturbance of the human gut microbiota in patients with Myotonic Dystrophy type 1.

Myotonic dystrophy type 1 (DM1) is a rare autosomal dominant genetic disorder. Although DM1 is primarily characterized by progressive muscular weakness, it exhibits many multisystemic manifestations, such as cognitive deficits, cardiac conduction abnormalities, and cataracts, as well as endocrine and reproductive issues. Additionally, the gastrointestinal (GI) tract is frequently affected, encompassing the entire digestive tract. However, the underlying causes of these GI symptoms remain uncertain, whether it is biomechanical problems of the intestine, involvement of bacterial communities, or both. The primary objective of this study is to investigate the structural changes in the gut microbiome of DM1 patients. To achieve this purpose, 35 patients with DM1 were recruited from the DM-Scope registry of the neuromuscular clinic in the Saguenay-Lac-St-Jean region of the province of Québec, Canada. Stool samples from these 35 patients, including 15 paired samples with family members living with them as controls, were collected. Subsequently, these samples were sequenced by 16S MiSeq and were analyzed with DADA2 to generate taxonomic signatures. Our analysis revealed that the DM1 status correlated with changes in gut bacterial community. Notably, there were differences in the relative abundance of Bacteroidota, Euryarchaeota, Fusobacteriota, and Cyanobacteria Phyla compared to healthy controls. However, no significant shift in gut microbiome community structure was observed between DM1 phenotypes. These findings provide valuable insights into how the gut bacterial community, in conjunction with biomechanical factors, could potentially influence the gastrointestinal tract of DM1 patients.

Characterization of muscle strength and mobility in oculopharyngeal muscular dystrophy.

INTRODUCTION/AIMS: Muscle weakness, and its association with mobility limitations, has received little study in oculopharyngeal muscular dystrophy (OPMD) using quantitative and standardized assessments. The objectives of this study were to (1) document upper and lower limb muscle strength, upper limb functions, fatigue, and mobility capacities; (2) compare them with reference values and across participant age groups; and (3) explore associations between muscle strength, fatigue, and mobility capacities among adults with OPMD. METHODS: Thirty-four participants were included in this cross-sectional study. The following variables were assessed: quantitative maximal isometric muscle strength, grip and pinch strength, fatigue, walking speed, walking endurance, sit-to-stand, and stair ascent and descent capacities. RESULTS: Muscle strength was lower for older than younger participants for five muscle groups (P < .05). Walking endurance, sit-to-stand, stairs (ascent and descent), and strength of hip flexion, grip, and pinch were below 80% of reference values in participants ≥56 y old (55.3%-78.2%). Moderate to strong correlations were found between muscle strength and mobility capacities (ρ = 0.42-0.80, P < .05), and between fatigue and either muscle strength or mobility capacities (ρ = 0.42-0.75, P < .05). DISCUSSION: This study highlights the impact of OPMD on strength, endurance, and functional capacity, among others, with patients being well below reference values even before the age of 65 y. In addition to helping health professionals to offer better clinical guidance, these results will improve clinical trial readiness. The next steps will be to assess the metrological properties of outcome measures and continue to document the disease progression rate.

Cannabis use in patients with Autosomal Recessive Spastic Ataxia of Charlevoix-Saguenay.

Autosomal Recessive Spastic Ataxia of Charlevoix-Saguenay (ARSACS) is an early-onset cerebellar ataxia with often presence of peripheral sensorimotor neuropathy and lower limb spasticity. Recently, the presence of pain has been associated with ARSACS in a quarter of the population in relation to spasms and neuropathic pain. However, limited therapeutic options available to patients and the occurrence of persistent symptoms despite treatment with the usual pharmacologic agents have led to exploring cannabis as a potential alternative. The aim of this study was to characterize the profile of cannabis use among patients with ARSACS. Phone interviews were conducted to document current or former cannabis use. Reasons of cannabis use and the characteristics of use were also investigated. Among the 50 study participants, 18% currently used cannabis, 40% reported at least one occurrence of cannabis use and 42% reported having never used cannabis. A greater proportion of patients with regular cannabis use reported chronic pain in comparison to those who never used. Although less frequent than ataxia, spasticity, muscle cramps or muscle spasms, which were independently reported by more than half of the studied sample, chronic pain was notably present in 30% of participants. While our study did not assess the therapeutic effects of cannabis, our results highlight that there is a potential role for cannabis and cannabinoids in the management of multiple ARSACS-associated symptoms and that agents modulating the endocannabinoid system need to be properly investigated.

Characterization of cannabis use by patients with myotonic dystrophy type 1: A pilot study.

The treatment of myotonic dystrophy type 1 (DM1) focuses on reducing symptom burden. However, since medication often fails to produce satisfying symptom relief, some patients seek alternatives, such as cannabis, to help reduce some of these symptoms. The aim of this study was to provide an accurate profile of cannabis use among DM1 patients. Phone interviews were conducted to identify current and former users, and to assess reasons for cannabis use. Characteristics of cannabis use were also investigated. Briefly, among the 72 study participants, 22.2% currently used cannabis and a majority of them (56.9%) reported using it to relieve symptoms associated with DM1. These users, classified as therapeutic users, reported poorer health status (EQ-5D index scores: 0.532±0.230 vs. 0.823±0.208, p = 0.020; EQ-VAS scale 50.56±10.74 vs. 75.57±21.50, p = 0.009) than non-therapeutic users. Finally, differences among sex were also highlighted. While the therapeutic effects of cannabis were not explored in our study, our results support the potential role of cannabis and cannabinoids in the treatment of DM1-associated symptoms which will need to be thoroughly investigated.

Placental Epigenome-Wide Association Study Identified Loci Associated with Childhood Adiposity at 3 Years of Age.

The aim of this study was to identify placental DNA methylation (DNAm) variations associated with adiposity at 3 years of age. We quantified placental DNAm using the Infinium MethylationEPIC BeadChips. We assessed associations between DNAm at single-CpGs and skinfold thickness using robust linear regression models adjusted for gestational age, child's sex, age at follow-up and cellular heterogeneity. We sought replication of DNAm association with child adiposity in an independent cohort. We quantified placental mRNA levels for annotated gene using qRT-PCR and tested for correlation with DNAm. Lower DNAm at cg22593959 and cg22436429 was associated with higher adiposity (ß = -1.18, q = 0.002 and ß = -0.82, q = 0.04). The cg22593959 is located in an intergenic region (chr7q31.3), whereas cg22436429 is within the TFAP2E gene (1p34.3). DNAm at cg22593959 and cg22436429 was correlated with mRNA levels at FAM3C (rs = -0.279, p = 0.005) and TFAP2E (rs = 0.216, p = 0.03). In an independent cohort, the association between placental DNAm at cg22593959 and childhood adiposity was of similar strength and direction (ß = -3.8 ± 4.1, p = 0.36), yet non-significant. Four genomic regions were also associated with skinfold thickness within FMN1, MAGI2, SKAP2 and BMPR1B genes. We identified placental epigenetic variations associated with adiposity at 3 years of age suggesting that childhood fat accretion patterns might be established during fetal life.

Mediation Analysis Supports a Causal Relationship between Maternal Hyperglycemia and Placental DNA Methylation Variations at the Leptin Gene Locus and Cord Blood Leptin Levels.

Changes in fetal DNA methylation (DNAm) of the leptin (LEP) gene have been associated with exposure to maternal hyperglycemia, but their links with childhood obesity risk are still unclear. We investigated the association between maternal hyperglycemia, placental LEP DNAm (25 5'-C-phosphate-G-3' (CpG) sites), neonatal leptinemia, and adiposity (i.e., BMI and skinfold thickness (ST) (subscapular (SS) + triceps (TR) skinfold measures, and the ratio of SS:TR) at 3-years-old, in 259 mother-child dyads, from Gen3G birth cohort. We conducted multivariate linear analyses adjusted for gestational age at birth, sex of the child, age at follow-up, and cellular heterogeneity. We assessed the causal role of DNAm in the association between maternal glycemia and childhood outcomes, using mediation analysis. We found three CpGs associated with neonatal leptinemia (p ≤ 0.002). Of these, cg05136031 and cg15758240 were also associated with BMI (ß = -2.69, p = 0.05) and fat distribution (ß = -0.581, p = 0.05) at 3-years-old, respectively. Maternal glycemia was associated with DNAm at cg15758240 (ß = -0.01, p = 0.04) and neonatal leptinemia (ß = 0.19, p = 0.004). DNAm levels at cg15758240 mediates 0.8% of the association between maternal glycemia and neonatal leptinemia (p < 0.001). Our results support that DNAm regulation of the leptin pathway in response to maternal glycemia might be involved in programming adiposity in childhood.

Methylation profiles of IL33 and CCL26 in bronchial epithelial cells are associated with asthma.

AIM: This study aimed to characterize DNA methylation (DNA-me) in promoter region of IL33, IL1RL1 and CCL26 in asthma and their impacts on transcriptional activity in bronchial epithelial cells (BECs). PATIENTS & METHODS: We performed bis-pyrosequencing, quantitative real-time PCR and sequencing in BECs from ten asthmatic and ten control individuals. RESULTS: We detected lower DNA-me levels of IL33 and CCL26 in asthmatic than control BECs. No correlation was found between methylation and expression levels. Interestingly, carriers of a mutative allele in a haplotype within the promoter of IL33 had a lower IL33 DNA-me level and CCL26 gene expression correlated with eosinophil count. CONCLUSION: These findings highlight the importance of investigating both epigenetic and genetic mechanisms in understanding the epithelial immune response in asthma.

DNA methylation of a PLPP3 MIR transposon-based enhancer promotes an osteogenic programme in calcific aortic valve disease.

Aims: Calcific aortic valve disease (CAVD) is characterized by the osteogenic transition of valve interstitial cells (VICs). In CAVD, lysophosphatidic acid (LysoPA), a lipid mediator with potent osteogenic activity, is produced in the aortic valve (AV) and is degraded by membrane-associated phospholipid phosphatases (PLPPs). We thus hypothesized that a dysregulation of PLPPs could participate to the osteogenic reprograming of VICs during CAVD. Methods and results: The expression of PLPPs was examined in human control and mineralized AVs and comprehensive analyses were performed to document the gene regulation and impact of PLPPs on the osteogenic transition of VICs. We found that PLPP3 gene and enzymatic activity were downregulated in mineralized AVs. Multidimensional gene profiling in 21 human AVs showed that expression of PLPP3 was inversely correlated with the level of 5-methylcytosine (5meC) located in an intronic mammalian interspersed repeat (MIR) element. Bisulphite pyrosequencing in a larger series of 67 AVs confirmed that 5meC in intron 1 was increased by 2.2-fold in CAVD compared with control AVs. In isolated cells, epigenome editing with clustered regularly interspersed short palindromic repeats-Cas9 system containing a deficient Cas9 fused with DNA methyltransferase (dCas9-DNMT) was used to increase 5meC in the intronic enhancer and showed that it reduced significantly the expression of PLPP3. Knockdown experiments showed that lower expression of PLPP3 in VICs promotes an osteogenic programme. Conclusions: DNA methylation of a MIR-based enhancer downregulates the expression of PLPP3 and promotes the mineralization of the AV.

Placental DNA Methylation Adaptation to Maternal Glycemic Response in Pregnancy.

Maternal hyperglycemia during pregnancy is associated with excess fetal growth and adverse perinatal and developmental outcomes. Placental epigenetic maladaptation may underlie these associations. We performed an epigenome-wide association study (>850,000 CpG sites) of term placentas and prenatal maternal glycemic response 2-h post oral glucose challenge at 24-30 weeks of gestation among 448 mother-infant pairs. Maternal 2-h glycemia postload was strongly associated with lower DNA methylation of four CpG sites (false discovery rate [FDR] q <0.05) within the phosphodiesterase 4B gene (PDE4B). Additionally, three other individual CpG sites were differentially methylated relative to maternal glucose response within the TNFRSF1B, LDLR, and BLM genes (FDR q <0.05). DNA methylation correlated with expression of its respective genes in placental tissue at three out of four independent identified loci: PDE4B (r = 0.31, P < 0.01), TNFRSF1B (r = -0.24, P = 0.013), and LDLR (r = 0.32, P < 0.001). In an independent replication cohort (N = 65-108 samples), results were consistent in direction but not significantly replicated among tested CpG sites in PDE4B and TNFRSF1B Our study provides evidence that maternal glycemic response during pregnancy is associated with placental DNA methylation of key inflammatory genes whose expression levels are partially under epigenetic control.

Placental lipoprotein lipase DNA methylation alterations are associated with gestational diabetes and body composition at 5 years of age.

Gestational diabetes mellitus (GDM) is associated with obesity in childhood. This suggests that consequences of in utero exposure to maternal hyperglycemia extend beyond the fetal development, possibly through epigenetic programming. The aims of this study were to assess whether placental DNA methylation (DNAm) marks were associated with maternal GDM status and to offspring body composition at 5 years old in a prospective birth cohort. DNAm levels were measured in the fetal side of the placenta in 66 samples (24 from GDM mothers) using bisDNA-pyrosequencing. Anthropometric and body composition (bioimpedance) were measured in children at 5 years of age. Mann-Whitney and Spearman tests were used to assess associations between GDM, placental DNAm levels at the lipoprotein lipase (LPL) locus and children's weight, height, body mass index (BMI), body fat, and lean masses at 5 years of age. Weight, height, and BMI z-scores were computed according to the World Health Organization growth chart. Analyses were adjusted for gestational age at birth, child sex, maternal age, and pre-pregnancy BMI. LPL DNAm levels were positively correlated with birth weight z-scores (r = 0.252, P = 0.04), and with mid-childhood weight z-scores (r = 0.314, P = 0.01) and fat mass (r = 0.275, P = 0.04), and negatively correlated with lean mass (r = -0.306, P = 0.02). We found a negative correlation between LPL DNAm and mRNA levels in placenta (r = -0.459; P < 0.001), which highlights the regulation of transcriptional activity by these epivariations. We demonstrated that alterations in fetal placental DNAm levels at the LPL gene locus are associated with the anthropometric profile in children at 5 years of age. These findings support the concept of fetal metabolic programming through epigenetic changes.

PPARGC1α gene DNA methylation variations in human placenta mediate the link between maternal hyperglycemia and leptin levels in newborns.

BACKGROUND: Children exposed to gestational diabetes mellitus (GDM) are at a higher risk of developing obesity and type 2 diabetes. This susceptibility might involve brown adipose tissue (BAT), which is suspected to protect against obesity. The objective of this study is to assess whether fetal exposure to maternal hyperglycemia is associated with DNA methylation variations in genes involved in BAT genesis and activation. METHODS: DNA methylation levels at the PRDM16, BMP7, CTBP2, and PPARGC1α gene loci were measured in placenta samples using bisulfite pyrosequencing in E-21 (n = 133; 33 cases of GDM) and the HumanMethylation450 array in Gen3G (n = 172, all from non-diabetic women) birth cohorts. Glucose tolerance was assessed in all women using an oral glucose tolerance test at the second trimester of pregnancy. Participating women were extensively phenotyped throughout pregnancy, and placenta and cord blood samples were collected at birth. RESULTS: We report that maternal glycemia at the second and third trimester of pregnancy are correlated with variations in DNA methylation levels at PRDM16, BMP7, and PPARGC1α and with cord blood leptin levels. Variations in PRDM16 and PPARGC1α DNA methylation levels were also correlated with cord blood leptin levels. Mediation analyses support that DNA methylation variations at the PPARGC1α gene locus explain 0.8 % of the cord blood leptin levels variance independently of maternal fasting glucose levels (p = 0.05). CONCLUSIONS: These results suggest that maternal glucose in pregnancy could produce variations in DNA methylation in BAT-related genes and that some of these DNA methylation marks seem to mediate the impact of maternal glycemia on cord blood leptin levels, an adipokine regulating body weight.

Interaction between the DNAH9 gene and early smoke exposure in bronchial hyperresponsiveness.

A previous genome-wide linkage scan of bronchial hyperresponsiveness (BHR) in the French Epidemiological study on the Genetics and Environment of Asthma (EGEA) families, performed in the presence of a gene×early-life environmental tobacco smoke (ETS) exposure interaction, showed the strongest interaction in the 17p11 region where linkage was detected only among unexposed siblings. Our goal was to conduct fine-scale mapping of 17p11 to identify single nucleotide polymorphisms (SNPs) interacting with ETS that influence BHR.Analyses were performed in 388 French EGEA asthmatic families, using a two-step strategy: 1) selection of SNPs displaying family-based association test (FBAT) association signals (p≤0.01) with BHR in unexposed siblings, and 2) a FBAT homogeneity test between exposed and unexposed siblings plus a robust log-linear interaction test.A single SNP reached the threshold (p≤3×10(-3)) for significant interaction with ETS using both interaction tests, after accounting for multiple testing. Results were replicated in 253 French-Canadian families, but not in 341 UK families, probably due in part to differences in phenotypic features between datasets.The SNP showing significant interaction with ETS belongs toDNAH9(dynein, axonemal, heavy chain 9), a promising candidate gene involved in respiratory cilia mobility and associated with primary ciliary dyskinesia, a disease associated with abnormalities of pulmonary function.

Local genotype influences DNA methylation at two asthma-associated regions, 5q31 and 17q21, in a founder effect population.

BACKGROUND: Two asthma-associated regions 17q12-q21 and 5q31.1 harbour genes that show strong effect of genotype on expression levels. DNA methylation has an important role in gene regulation; therefore, we examined DNA methylation at promoters of 12 genes from 5q31 and 17q12-q21 regions. Our goal was to determine whether DNA methylation was associated with predisposition to asthma and whether such a relationship was independent from genetic association. METHODS: Using sodium bisulfite sequencing and pyrosequencing methylation assays, we examined the effect of genotype on DNA methylation in peripheral blood cells from individuals from the Saguenay-Lac-Saint-Jean asthma familial collection and lymphoblastoid cell lines. RESULTS: The local genotype influenced methylation levels of solute carrier family 22 (organic 3 cation/carnitine transporter) member 5 (SLC22A5), zona pellucida binding protein 2 (ZPBP2) and gasdermin A (GSDMA) promoter regions. The genotype had a dominant effect on ZPBP2 and GSDMA methylation with lower methylation levels in individuals that carry the asthma-predisposing alleles. Males also had lower methylation at the ZPBP2 promoter than females. We did not observe an effect of asthma status that would be independent of the genotype and the sex effects in the GSDMA, ZPBP2 and SLC22A5 regions; however, GSDMA and ZPBP2 data were suggestive of interaction between asthma and methylation levels in females and SLC22A5 in males. CONCLUSIONS: The local genotype influences methylation levels at SLC22A5 and ZPBP2 promoters independently of the asthma status. Further studies are necessary to confirm the relationship between GSDMA-ZPBP2 and SLC22A5 methylation and asthma in females and males separately.

DNA methylation signature of interleukin 1 receptor type II in asthma.

Interleukin 1 and its receptors are associated with allergic diseases such as asthma. In the present study, we measured DNA methylation at the IL1R1 and IL1R2 gene loci and assessed for associations with asthma-related phenotypes and gene expressions. We found that asthmatic and atopic individuals have higher IL1R2 promoter DNA methylation than control subjects. Additionally, we observed a negative correlation between DNA methylation at the IL1R2 promoter and IL1R2 mRNA expression. These results suggest for the first time that IL1R2 promoter DNA methylation is associated with its gene repression in allergic diseases such as asthma.