Citations

AbstractObjectiveOnset of multiple sclerosis (MS) occurs in childhood for approximately 5% of cases (pediatricMS, or ped‐MS). Epigenetic influences are strongly implicated inMSpathogenesis in adults, including the contribution from microRNAs (miRNAs), small noncodingRNAs that affect gene expression by binding target genemRNAs. Few studies have specifically examined miRNAs in ped‐MS, but individuals developingMSat an early age may carry a relatively high burden of genetic risk factors, and miRNAdysregulation may therefore play a larger role in the development of ped‐MSthan in adult‐onsetMS. This study aimed to look for evidence of miRNAinvolvement in ped‐MSpathogenesis.MethodsGWASresults from 486 ped‐MScases and 1362 controls from the U.S. PediatricMSNetwork and Kaiser Permanente Northern California membership were investigated for miRNA‐specific signals. First, enrichment of miRNA‐target gene network signals was evaluated usingMIGWASsoftware. Second,SNPs in miRNAgenes and in target gene binding sites (miR−SNPs) were tested for association with ped‐MS, and pathway analysis was performed on associated target genes.ResultsMIGWASanalysis showed that miRNA‐target gene signals were enriched inGWAS(P = 0.038) and identified 39 candidate biomarker miRNA‐target gene pairs, including immune and neuronal signaling genes. The miR‐SNPanalysis implicated dysregulation of miRNAbinding to target genes in five pathways, mainly involved in immune signaling.InterpretationEvidence fromGWASsuggests that miRNAs play a role in ped‐MSpathogenesis by affecting immune signaling and other pathways. Candidate biomarker miRNA‐target gene pairs should be further studied for diagnostic, prognostic, and/or therapeutic utility.

Background and objectives To evaluate the growth pattern of kidney cyst number and cyst volume in association with kidney size, demographics, and genotypes in autosomal dominant polycystic kidney disease. Design, setting, participants, & measurements Kidney cyst number and cyst volume were measured from serial magnetic resonance images, giving a maximum follow-up of 14.23 years, from 241 patients with autosomal dominant polycystic kidney disease (15–46 years old at baseline). The growth pattern was analyzed, in association with sex, age, height-adjusted total kidney volume, and genotype, using linear mixed models of repeated measurements and tests of interactions with age (as a time-dependent covariate) to assess rates of change over time. Models were also fit using Irazabal class. Genotypic groups were characterized as either ( 1 ) PKD1 truncating, PKD1 nontruncating, and PKD2 plus patients with no mutation detected; or ( 2 ) in combination with PKD1 mutation strength groups. Results Imaging and genetic data were collected (at least one visit) for 236 participants. The mean height-adjusted total cyst number increased exponentially over time from a baseline value of 762 to 1715 at the last clinic visit, while the mean height-adjusted total cyst volume increased exponentially from 305 to 770 ml. Height-adjusted total kidney volume, height-adjusted total cyst number, and height-adjusted total cyst volume were all highly correlated over time. Female participants and participants with larger height-adjusted total kidney volume at baseline showed smaller rates of change in the log of height-adjusted total cyst number and cyst volume. PKD1 was associated with significant increases in both cyst number and volume at a given age, but genotype did not significantly affect the rate of growth. Conclusions Both height-adjusted total cyst number and height-adjusted total cyst volume increased exponentially and more than doubled over 14.23 years of follow-up. Compared with PKD2 plus no mutation detected, PKD1 was associated with a greater cyst number and volume at a given age, but no significant difference in the rate of growth.

Objective: The aim of this study was to determine whether a vitamin D genetic risk score (vitDGRS) is associated with 25-hydroxyvitamin D (25(OH)D) level and multiple sclerosis (MS) relapses in children. Methods: DNA samples were typed for single nucleotide polymorphisms (SNPs) from four genes previously identified to be associated with 25(OH)D levels. SNPs with strong associations with 25(OH)D after multiple comparison correction were used to create a genetic risk score (vitDGRS). Cox regression models tested associations of vitDGRS with relapse hazard. Results: Two independent SNPs within or near GC and NADSYN1/DHCR7 genes were strongly associated with 25(OH)D levels in the discovery cohort ( n = 182) after Bonferroni correction. The vitDGRS of these SNPs explained 4.5% of the variance of 25(OH)D level after adjustment for genetic ancestry. Having the highest versus lowest vitDGRS was associated with 11 ng/mL lower 25(OH)D level (95% confidence interval (CI) = −17.5, −4.5, p = 0.001) in the discovery cohort. Adjusting for ancestry, sex, disease-modifying therapy (DMT), and HLA-DRB1*15 carrier status, the highest versus lowest vitDGRS was associated with 2.6-fold (95% CI = 1.37, 5.03, p = 0.004) and 2.0-fold (95% CI = 0.75, 5.20, p = 0.16) higher relapse hazard in the discovery and replication cohorts, respectively. Conclusion: The vitDGRS identifies children at greater risk of relapse. These findings support a causal role for vitamin D in MS course.

Metabolic syndrome (MetS) is associated with nutrient surplus and kidney hyperfiltration, accelerating chronic renal failure. The potential involvement of podocyte damage in early MetS remains unclear. Mitochondrial dysfunction is an important determinant of renal damage, but whether it contributes to MetS-related podocyte injury remains unknown. Domestic pigs were studied after 16 wk of diet-induced MetS, MetS treated with the mitochondria-targeted peptide elamipretide (ELAM; 0.1 mg·kg−1·day−1 sc) for the last month of diet, and lean controls ( n = 6 pigs/group). Glomerular filtration rate (GFR) and renal blood flow (RBF) were measured using multidetector computed tomography, and podocyte and mitochondrial injury were measured by light and electron microscopy. Urinary levels of podocyte-derived extracellular vesicles (pEVs; nephrin positive/podocalyxin positive) were characterized by flow cytometry. Body weight, blood pressure, RBF, and GFR were elevated in MetS. Glomerular size and glomerular injury score were also elevated in MetS and decreased after ELAM treatment. Evidence of podocyte injury, impaired podocyte mitochondria, and foot process width were all increased in MetS but restored with ELAM. The urinary concentration of pEVs was elevated in MetS pigs and directly correlated with renal dysfunction, glomerular injury, and fibrosis and inversely correlated with glomerular nephrin expression. Additionally, pEV numbers were elevated in the urine of obese compared with lean human patients. Early MetS induces podocyte injury and mitochondrial damage, which can be blunted by mitoprotection. Urinary pEVs reflecting podocyte injury might represent early markers of MetS-related kidney disease and a novel therapeutic target.

Abstract Waiting impulsivity is a risk factor for many psychiatric disorders including alcohol use disorder (AUD). Highly impulsive individuals are vulnerable to alcohol abuse. However, it is not well understood whether chronic alcohol use increases the propensity for impulsive behavior. Here, we establish a novel experimental paradigm demonstrating that continuous binge‐like ethanol exposure progressively leads to maladaptive impulsive behavior. To test waiting impulsivity, we employed the 5‐choice serial reaction time task (5‐CSRTT) in C57BL/6J male mice. We assessed premature responses in the fixed and variable intertrial interval (ITI) 5‐CSRTT sessions. We further characterized our ethanol‐induced impulsive mice using Open Field, y‐maze, two‐bottle choice, and an action‐outcome task. Our results indicate that continuous binge‐like ethanol exposure significantly increased premature responses when mice were tested in variable ITI sessions even during a prolonged abstinent period. Ethanol‐induced impulsive mice exhibited anxiety‐like behavior during chronic exposures. This behavior was also observed in a separate cohort that was subjected to 20 days of abstinence. Ethanol‐treated mice were less motivated for a sucrose reward compared with air‐exposed control mice, while also demonstrating reduced responding during action‐outcome testing. Overall, ethanol‐treated mice demonstrated increased impulsive behavior, but a reduced motivation for a sucrose reward. Although waiting impulsivity has been hypothesized to be a trait or risk factor for AUD, our findings indicate that maladaptive impulse control can also be potentiated or induced by continuous chronic ethanol exposure in mice.

ObjectiveTo evaluate whether global peak systolic strain (PSS) and peak systolic strain rate (PSSR) derived from velocity vector imaging (VVI) allow early recognition of regional and global right ventricular (RV) dysfunction and the impact of this on left ventricular (LV) function in patients with pulmonary hypertension (PHT).BackgroundRV function is an important determinant of prognosis in patients with heart failure, pulmonary hypertension, heart transplant, and congenital heart diseases. However, evaluation of the right ventricle is often limited by its complex geometry and inadequate visualization of RV free wall. Furthermore, the impact of RV dysfunction on the LV function is not well elucidated.MethodsNinety‐nine participants, 35 control patients with normal RV systolic pressure (RVSP) (<30 mm Hg) and 64 patients with PHT (25 with mild‐to‐moderate increase in RVSP [≥36 and <60 mm Hg] and 39 with severe increase in RVSP [≥60 mm Hg]), underwent comprehensive echo‐Doppler assessment and velocity vector imaging (VVI) for strain rate analysis. RV regional peak systolic and diastolic tangential velocity, strain, and strain rate were obtained from the basal, mid and apical segments of the RV free wall and interventricular septum (IVS) from apical 4‐chamber view at end‐expiration. Similar data were obtained from eighteen LV segments from apical 4‐chamber, 2‐chamber, and long‐axis views.ResultsPeak systolic strain, strain rate, and tangential velocity at all segments in the RV free wall and IVS were decreased compared to controls in patients with PHT (P < 0.001). Significant correlation (r > 0.60; P < 0.001) was noted between RVSP and systolic and diastolic strain and strain rate at basal segment in IVS and global RV function. Peak early diastolic strain rate at all segments was also decreased in PHT patients compared with control patients (P < 0.01). Furthermore, RV systolic and diastolic strain and strain rate were lower in group 2 with mild‐to‐moderate hypertension while the conventional echo parameters were normal. Except for IVS segments, other LV segments had no statistical differences in systolic and diastolic velocity, strain, and strain rate compared to controls. However, they were lower than the published normal range.ConclusionsStrain and strain rate derived from VVI demonstrates early recognition of systolic and diastolic RV dysfunction in patients with PHT compared to controls. PHT is associated with global and regional RV systolic and diastolic dysfunction. Systolic and diastolic strain and strain rate from LV was lower compared to controls but were not statistically significant. This may indicate subclinical LV dysfunction in these patients, suggesting that conventional LV function parameters may not be sensitive to recognize subclinical LV dysfunction.

Apolipoprotein E (apoE) is linked to the risk for Alzheimer’s disease (AD) and thus has been suggested to be an important therapeutic target. In our drug screening effort, we identified Ondansetron (OS), an FDA-approved 5-HT3 antagonist, as an apoE-modulating drug. OS at low micromolar concentrations significantly increased apoE secretion from immortalized astrocytes and primary astrocytes derived from apoE3 and apoE4-targeted replacement mice without generating cellular toxicity. Other 5-HT3 antagonists also had similar effects as OS, though their effects were milder and required higher concentrations. Antagonists for other 5-HT receptors did not increase apoE secretion. OS also increased mRNA and protein levels of the ATB-binding cassette protein A1 (ABCA1), which is involved in lipidation and secretion of apoE. Accordingly, OS increased high molecular weight apoE. Moreover, the liver X receptor (LXR) and ABCA1 antagonists blocked the OS-induced increase of apoE secretion, indicating that the LXR-ABCA1 pathway is involved in the OS-mediated facilitation of apoE secretion from astrocytes. The effects of OS on apoE and ABCA1 were also observed in human astrocytes derived from induced pluripotent stem cells (iPSC) carrying the APOE ε3/ε3 and APOE ε4/ε4 genotypes. Oral administration of OS at clinically-relevant doses affected apoE levels in the liver, though the effects in the brain were not observed. Collectively, though further studies are needed to probe its effects in vivo, OS could be a potential therapeutic drug for AD by modulating poE metabolism through the LXR-ABCA1 pathway.