Craniofacial features of POLR3-related leukodystrophy caused by biallelic variants in POLR3A, POLR3B and POLR1C.

BACKGROUND: RNA polymerase III-related or 4H leukodystrophy (POLR3-HLD) is an autosomal recessive hypomyelinating leukodystrophy characterized by neurological dysfunction, hypodontia and hypogonadotropic hypogonadism. The disease is caused by biallelic pathogenic variants in POLR3A, POLR3B, POLR1C or POLR3K. Craniofacial abnormalities reminiscent of Treacher Collins syndrome have been originally described in patients with POLR3-HLD caused by biallelic pathogenic variants in POLR1C. To date, no published studies have appraised in detail the craniofacial features of patients with POLR3-HLD. In this work, the specific craniofacial characteristics of patients with POLR3-HLD associated with biallelic pathogenic variants in POLR3A, POLR3B and POLR1C are described. METHODS: The craniofacial features of 31 patients with POLR3-HLD were evaluated, and potential genotype-phenotype associations were evaluated. RESULTS: Various craniofacial abnormalities were recognized in this patient cohort, with each individual presenting at least one craniofacial abnormality. The most frequently identified features included a flat midface (61.3%), a smooth philtrum (58.0%) and a pointed chin (51.6%). In patients with POLR3B biallelic variants, a thin upper lip was frequent. Craniofacial anomalies involving the forehead were most commonly associated with biallelic variants in POLR3A and POLR3B while a higher proportion of patients with POLR1C biallelic variants demonstrated bitemporal narrowing. CONCLUSION: Through this study, we demonstrated that craniofacial abnormalities are common in patients with POLR3-HLD. This report describes in detail the dysmorphic features of POLR3-HLD associated with biallelic variants in POLR3A, POLR3B and POLR1C.

Human plasma pregnancy-associated miRNAs and their temporal variation within the first trimester of pregnancy.

BACKGROUND: During pregnancy, maternal metabolism undergoes substantial changes to support the developing fetus. Such changes are finely regulated by different mechanisms carried out by effectors such as microRNAs (miRNAs). These small non-coding RNAs regulate numerous biological functions, mostly through post-transcriptional repression of gene expression. miRNAs are also secreted in circulation by numerous organs, such as the placenta. However, the complete plasmatic microtranscriptome of pregnant women has still not been fully described, although some miRNA clusters from the chromosome 14 (C14MC) and the chromosome 19 (C19MC and miR-371-3 cluster) have been proposed as being specific to pregnancy. Our aims were thus to describe the plasma microtranscriptome during the first trimester of pregnancy, by assessing the differences with non-pregnant women, and how it varies between the 4th and the 16th week of pregnancy. METHODS: Plasmatic miRNAs from 436 pregnant (gestational week 4 to 16) and 15 non-pregnant women were quantified using Illumina HiSeq next-generation sequencing platform. Differentially abundant miRNAs were identified using DESeq2 package (FDR q-value ≤ 0.05) and their targeted biological pathways were assessed with DIANA-miRpath. RESULTS: A total of 2101 miRNAs were detected, of which 191 were differentially abundant (fold change < 0.05 or > 2, FDR q-value ≤ 0.05) between pregnant and non-pregnant women. Of these, 100 miRNAs were less and 91 miRNAs were more abundant in pregnant women. Additionally, the abundance of 57 miRNAs varied according to gestational age at first trimester, of which 47 were positively and 10 were negatively associated with advancing gestational age. miRNAs from the C19MC were positively associated with both pregnancy and gestational age variation during the first trimester. Biological pathway analysis revealed that these 191 (pregnancy-specific) and 57 (gestational age markers) miRNAs targeted genes involved in fatty acid metabolism, ECM-receptor interaction and TGF-beta signaling pathways. CONCLUSION: We have identified circulating miRNAs specific to pregnancy and/or that varied with gestational age in first trimester. These miRNAs target biological pathways involved in lipid metabolism as well as placenta and embryo development, suggesting a contribution to the maternal metabolic adaptation to pregnancy and fetal growth.

Altered DNA Methylation of Long Noncoding RNA H19 in Calcific Aortic Valve Disease Promotes Mineralization by Silencing NOTCH1.

BACKGROUND: Calcific aortic valve disease is characterized by an abnormal mineralization of the aortic valve. Osteogenic activity in the aortic valve is under the control of NOTCH1, which regulates the expression of key pro-osteogenic genes such as RUNX2 and BMP2. Long noncoding RNAs (lncRNAs) may reprogram cells by altering the gene expression pattern. METHODS: Multidimensional genomic profiling was performed in human aortic valves to document the expression of lncRNAs and the DNA methylation pattern in calcific aortic valve disease. In-depth functional assays were carried out to document the impact of lncRNA on the mineralization of the aortic valve. RESULTS: We documented that lncRNA H19 (H19) was increased in calcific aortic valve disease. Hypomethylation of the promoter region was observed in mineralized aortic valves and was inversely associated with H19 expression. Knockdown and overexpression experiments showed that H19 induces a strong osteogenic phenotype by altering the NOTCH1 pathway. Gene promoter analyses showed that H19 silenced NOTCH1 by preventing the recruitment of p53 to its promoter. A knockdown of H19 in valve interstitial cells (VICs) increased the expression of NOTCH1 and decreased the level of RUNX2 and BMP2, 2 downstream targets repressed by NOTCH1. In rescue experiments, the transfection of a vector encoding for the active Notch intracellular domain prevented H19-induced mineralization of valve interstitial cells. CONCLUSIONS: These findings indicate that a dysregulation of DNA methylation in the promoter of H19 during calcific aortic valve disease is associated with a higher expression of this lncRNA, which promotes an osteogenic program by interfering with the expression of NOTCH1.

Prevalence of Dysbetalipoproteinemia in the UK Biobank According to Different Diagnostic Criteria.

CONTEXT: Dysbetalipoproteinemia (DBL) is a multifactorial disorder that disrupts the normal metabolism of remnant lipoproteins, causing increased risk of cardiovascular disease. However, establishing a proper diagnosis is difficult and the true prevalence of the disease in the general population remains unknown. OBJECTIVE: The objectives were to study the prevalence of the disease and to validate the performance of different clinical diagnostic criteria in a large population-based cohort. METHODS: This study included 453 437 participants from the UK Biobank. DBL was established in participants having an ε2ε2 genotype with mixed dyslipidemia or lipid-lowering therapy use (n=964). The different diagnostic criteria for DBL were applied in individuals without lipid-lowering medication (n=370 039, n=534 DBL), to compare their performance. RESULTS: Overall, 0.6% of participants had an ε2ε2 genotype, of which 36% were classified as DBL, for a disease prevalence of 0.2% (1:469). The prevalence of DBL was similar between the different genetic ancestries (≤0.2%). Several diagnostic criteria showed good sensitivity for the diagnosis of DBL (>90%), but they suffered from a very low positive predictive value (0.6%-15.4%). CONCLUSION: This study reported for the first time the prevalence of DBL in the UK Biobank according to genetic ancestry. Furthermore, we provided the first external validation of different diagnostic criteria for DBL in a large population-based cohort and highlighted the fact that these criteria should not be used to diagnose DBL alone but should rather be used as a first screening step to determine which individuals may benefit from genetic testing to confirm the diagnosis.

Two Cases of Sitosterolemia Falsely Diagnosed as Familial Hypercholesterolemia: Could Digging Deeper Have Avoided Harm?

Sitosterolemia is a rare monogenic lipid disease characterized by the excessive uptake of phytosterols and their accumulation in blood and tissues. Clinically, it can present with hypercholesterolemia and xanthomas, often causing it to be misdiagnosed as familial hypercholesterolemia (FH). The diagnosis of sitosterolemia can easily be confirmed and distinguished from FH with a sterol profile and genetic investigations. Here, we report a sibship of 2 sisters with sitosterolemia initially misdiagnosed as FH. This case report illustrates the importance of considering rare conditions, such as sitosterolemia, as a differential diagnosis in patients with hypercholesterolemia, xanthomas, and hematologic anomalies. It also emphasizes the underdiagnosis of sitosterolemia and the benefits of using sterol profiles and genetic testing in the diagnostic process to initiate the appropriate therapy and avoid harm to patients.

The 20-Year Diagnostic Odyssey of a Milder Form of Cerebrotendinous Xanthomatosis.

Tendinous xanthomas are usually a sign of genetic dyslipidemias and are said to be pathognomonic for familial hypercholesterolemia. However, the differential diagnosis must also include rarer forms of genetic dyslipidemias such as cerebrotendinous xanthomatosis (CTX). In this report, we present the diagnostic odyssey of a French-Canadian patient presenting with Achilles tendon xanthomas and an unusual mild to moderate hypercholesterolemia. Comprehensive biochemical and genetic investigations confirmed the diagnosis of CTX, 20 years after the onset of her first symptoms. We also describe a new variant in the CYP27A1 gene associated with this atypical case and expand the clinical phenotype of this rare genetic condition. CTX is thought to be underdiagnosed, and early diagnosis and treatment of this disease is essential as it has been shown to greatly improve the patient's symptoms and prognosis.

High hsCRP concentration is associated with acute pancreatitis in multifactorial chylomicronemia syndrome.

BACKGROUND: Multifactorial chylomicronemia syndrome (MCS) is a severe form of hypertriglyceridemia (hyperTG) associated with an increased risk of acute pancreatitis (AP). However, the risk of AP is very heterogenous in MCS. Previous studies suggested that inflammation might promote disease progression in hyperTG-induced AP. OBJECTIVE: To determine if low-grade inflammation is associated with AP in MCS. METHODS: This study included 102 subjects with MCS for which high-sensitivity C-reactive protein (hsCRP) concentration was measured at their first visit at the Montreal Clinical Research Institute. RESULTS: MCS subjects with a previous history of AP had a significant higher hsCRP concentration (4.62 mg/L vs. 2.61 mg/L; p=0.003) and high hsCRP concentration (≥3mg/L) was independently associated with AP prevalence (p<0.05). Up to 64% of the variability in AP prevalence was explained by the maximal TG concentration, hsCRP concentration, the presence of rare variants in TG-related genes, and fructose intake based on a stepwise multivariate regression model (p<0.0001). CONCLUSION: This retrospective study showed for the first time that hsCRP concentration is strongly associated with AP prevalence in MCS. It also suggests that low-grade inflammation may be a driver of AP in severe hypertriglyceridemia. Prospective studies could help determine the causality of this association and assess whether medication known to reduce low-grade inflammation could help prevent AP in individuals with severe hypertriglyceridemia.

Pancreatitis polygenic risk score is associated with acute pancreatitis in multifactorial chylomicronemia syndrome.

BACKGROUND: Multifactorial chylomicronemia syndrome (MCS) is a severe form of hypertriglyceridemia associated with an increased risk of acute pancreatitis (AP). The risk of AP is heterogenous and is associated with increased level of triglycerides (TG) and presence of rare variants in TG metabolism-related genes. OBJECTIVE: To determine if the accumulation of common variants in pancreatitis susceptibility genes, measured with a weighted polygenic risk score (PRS), is associated with AP in MCS patients. METHODS: A total of 114 patients with MCS underwent genetic testing for eight single nucleotide polymorphisms (SNPs) in known pancreatitis susceptibility genes (ABCG8, CLDN2, CTRB1/2, CTRC, PRSS1, PRSS2, SPINK1 and TWIST2). A weighted PRS was calculated to account for the phenotypic effect of each SNP locus. RESULTS: A high pancreatitis-PRS score (≥ 0.44) was associated with a 2.94-fold increase risk of AP (p = 0.02) among patients with MCS. MCS patients with a high pancreatitis-PRS and a rare variant in TG metabolism-related gene have a 9.50-fold increase risk of AP (p = 0.001), compared to those with a low-PRS and no rare variant. A multivariate analysis including the presence of rare variants, the maximal TG values and a high pancreatitis-PRS explained 26% of the variability in AP in MCS patients. CONCLUSION: This study shows for the first time that the accumulation of common variants in pancreatitis susceptibility genes is associated with AP in MCS patients. Pancreatitis-PRS could help clinicians to identify MCS patients who may be at higher risk of AP and who may benefit from more aggressive treatment.

High carrier frequency for abetalipoproteinemia and evidence of a founder variant in a French-Canadian population.

Abetalipoproteinemia (ABL) is a rare recessive genetic disease caused by bi-allelic pathogenic variants in the microsomal triglyceride transfer protein (MTTP) gene. This disease is characterized by a deficiency in the secretion of apolipoprotein B-containing lipoproteins. Patients with ABL present with neurological, hematological, and gastrointestinal symptoms due to fat malabsorption and a deficiency in liposoluble vitamins. In this report, we present a total of four ABL cases, including three new cases, all originating from the same French-Canadian founder population in Saguenay-Lac-Saint-Jean, Québec, Canada. These individuals are homozygous for the same pathogenic variant in the MTTP gene (c.419dup, p.Asn140Lysfs*2). We found that this variant is more common than anticipated in this population, with an estimated carrier frequency of 1:203. Early diagnosis is essential to initiate treatment known to prevent complications associated with ABL. Population carrier screening or newborn screening for ABL should be considered in this French-Canadian founder population.

Acute pancreatitis risk in multifactorial chylomicronemia syndrome depends on the molecular cause of severe hypertriglyceridemia.

BACKGROUND AND AIMS: Multifactorial chylomicronemia syndrome (MCS) is a severe form of hypertriglyceridemia (hyperTG) associated with an increased risk of acute pancreatitis (AP). Severe hyperTG is mainly polygenic in nature, either caused by the presence of heterozygous pathogenic variants (PVs) in TG-related metabolism genes or by accumulation of common variants in hyperTG susceptibility genes. This study aims to determine if the risk of AP is similar amongst MCS patients with different molecular causes of severe hyperTG. METHODS: This study included 114 MCS patients who underwent genetic testing for PVs in TG-related metabolism genes and 16 single nucleotide polymorphisms (SNPs) in hyperTG susceptibility genes. A weighted TG-polygenic risk score (TG-PRS) was calculated. A TG-PRS score ≥ 90th percentile was used to define a high TG-PRS. RESULTS: Overall, 66.7% of patients had severe hyperTG of polygenic origin. MCS patients with only a PV and those with both a PV and high TG-PRS were more prone to have maximal TG concentration ≥ 40 mmol/L (OR 5.33 (1.55-18.36); p = 0.008 and OR 5.33 (1.28-22.25); p = 0.02), as well as higher prevalence of AP (OR 3.64 (0.89-14.92); p = 0.07 and OR 11.90 (2.54-55.85); p = 0.002) compared to MCS patients with high TG-PRS alone. CONCLUSIONS: This is the first study to show that MCS caused by a high TG-PRS and a PV is associated with higher risk of AP, similar to what is seen in the monogenic form of severe hyperTG. This suggests that determining the molecular cause of severe hyperTG could be useful to stratify the risk of pancreatitis in MCS.

A founder mutation in the PEX6 gene is responsible for increased incidence of Zellweger syndrome in a French Canadian population.

BACKGROUND: Zellweger syndrome (ZS) is a peroxisome biogenesis disorder due to mutations in any one of 13 PEX genes. Increased incidence of ZS has been suspected in French-Canadians of the Saguenay-Lac-St-Jean region (SLSJ) of Quebec, but this remains unsolved. METHODS: We identified 5 ZS patients from SLSJ diagnosed by peroxisome dysfunction between 1990-2010 and sequenced all coding exons of known PEX genes in one patient using Next Generation Sequencing (NGS) for diagnostic confirmation. RESULTS: A homozygous mutation (c.802_815del, p.[Val207_Gln294del, Val76_Gln294del]) in PEX6 was identified and then shown in 4 other patients. Parental heterozygosity was confirmed in all. Incidence of ZS was estimated to 1 in 12,191 live births, with a carrier frequency of 1 in 55. In addition, we present data suggesting that this mutation abolishes a SF2/ASF splice enhancer binding site, resulting in the use of two alternative cryptic donor splice sites and predicted to encode an internally deleted in-frame protein. CONCLUSION: We report increased incidence of ZS in French-Canadians of SLSJ caused by a PEX6 founder mutation. To our knowledge, this is the highest reported incidence of ZS worldwide. These findings have implications for carrier screening and support the utility of NGS for molecular confirmation of peroxisomal disorders.

Clinical utility of methionine restriction in adenosine kinase deficiency.

Adenosine kinase (ADK) deficiency is a rare autosomal recessive inborn error of metabolism involving the methionine and purine metabolic pathways. Prior reports show that most patients present in infancy with jaundice, hypotonia, developmental delay, and mild dysmorphic features. Characteristic biochemical findings included hypoglycemic hyperinsulinism, cholestasis, elevated liver functions, methionine, S-adenosylhomocysteine, and S-adenosylmethionine, with normal or mildly elevated homocysteine level. Brain imaging demonstrated atrophy, hydrocephalus, and delayed myelination. There are 26 reported patients of ADK deficiency, of which 14 patients were placed on a methionine-restricted diet. Clinical improvement with methionine restriction was not well described. CASE REPORT: We report an infant who presented at birth with persistently elevated ammonia (100-163 µmol/L), hypoglycemia, cholestasis, and liver dysfunction. The initial metabolic and genetic work-up was nondiagnostic, with only a mildly increased plasma methionine level (51 [<38 µmol/L]). Iron depositions in the liver and in lip mucosa led to suspicion of gestational alloimmune liver disease. Immunoglobulin therapy and exchange transfusion treatments demonstrated transient clinical and biochemical improvements. However, subsequent episodes of acute liver failure with development of neurological abnormalities led to further evaluation. Metabolic studies showed a 25-fold increase in plasma methionine level at 8 months of life (1022 [<38 µmol/L]) with white matter abnormalities on brain MRI. Expanded molecular testing identified the disease. Urinary purines profile showed elevations of adenosine and related metabolites. Introduction of a low-methionine diet resulted in rapid clinical amelioration, improvement of brain MRI findings, and normalization of liver functions and methionine levels.

HDL-enriched miR-30a-5p is associated with HDL-cholesterol levels and glucose metabolism in healthy men and women.

Aim: To investigate the associations between high-density lipoprotein (HDL)-enriched miRNAs and the cardiometabolic profile of healthy men and women. Patients & methods: miRNAs were quantified using next-generation sequencing of miRNAs extracted from purified HDL and plasma from 17 healthy men and women couples. Results: Among the HDL-enriched miRNAs, miR-30a-5p correlated positively with HDL-cholesterol levels, whereas miR-144-5p and miR-30a-5p were negatively associated with fasting insulin levels and Homeostasis model assessment of insulin resistance index. Overall, miR-30a-5p, miR-150-5p and sex contributed to 45% of HDL-cholesterol variance. A model containing only miR-30a-5p, age and sex explained 41% of fasting glucose variance. Conclusion: HDL-enriched miRNAs, notably miR-30a-5p, are associated with cardiometabolic markers. These miRNAs could play a role in HDL's protective functions, particularly regarding glucose-insulin homeostasis.

The "hypertriglyceridemic waist" phenotype and glucose intolerance in pregnancy.

BACKGROUND: Abdominal visceral adiposity in early pregnancy has been associated with impaired glucose tolerance in later pregnancy. The "hypertriglyceridemic waist" phenotype (i.e., abdominal obesity in combination with hyper-triglyceridemia) is a clinical marker of visceral obesity. Our study aimed to assess the association between the hyper-triglyceridemic-waist phenotype in early pregnancy and glucose intolerance in later pregnancy. METHODS: Plasma triglycerides and waist girth were measured at 11-14 weeks of gestation among 144 white pregnant women. Glycemia was measured following a 75-g oral glucose tolerance test performed at 24-28 weeks of gestation. RESULTS: A waist girth greater than 85 cm in combination with a triglyceride level ≥ 1.7 mmol/L in the first trimester was associated with an increased risk of two-hour glucose ≥ 7.8 mmol/L following the 75-g oral glucose tolerance test (odds ratio [OR] 6.1, p = 0.002). This risk remained significant even after we controlled for maternal age, fasting glucose at first trimester and previous history of gestational diabetes (OR 4.7, p = 0.02). INTERPRETATION: Measurement of waist girth in combination with measurement of triglyceride concentrations in the first trimester of pregnancy could improve early screening for gestational glucose intolerance.

DNA methylation at the DMPK gene locus is associated with cognitive functions in myotonic dystrophy type 1.

Aim: Myotonic dystrophy type 1 (DM1) is caused by an unstable trinucleotide (CTG) expansion at the DMPK gene locus. Cognitive dysfunctions are often observed in the condition. We investigated the association between DMPK blood DNA methylation (DNAm) and cognitive functions in DM1, considering expansion length and variant repeats (VRs). Method: Data were obtained from 115 adult-onset DM1 patients. Molecular analyses consisted of pyrosequencing, small pool PCR and Southern blot hybridization. Cognitive functions were assessed by validated neuropsychological tests. Results: For patients without VRs (n = 103), blood DNAm at baseline independently contributed to predict cognitive functions 9 years later. Patients with VRs (n = 12) had different DNAm and cognitive profiles. Conclusion: DNAm allows to better understand DM1-related cognitive dysfunction etiology.

DNA methylation at LRP1 gene locus mediates the association between maternal total cholesterol changes in pregnancy and cord blood leptin levels.

Placental lipids transfer is essential for optimal fetal development, and alterations of these mechanisms could lead to a higher risk of adverse birth outcomes. Low-density lipoprotein receptor (LDLR), LDL receptor-related protein 1 (LRP1), and scavenger receptor class B type 1 (SCARB1) genes are encoding lipoprotein receptors expressed in the placenta where they participate in cholesterol exchange from maternal to fetal circulation. The aim of this study was thus to investigate the association between maternal lipid changes occurring in pregnancy, placental DNA methylation (DNAm) variations at LDLR, LRP1, and SCARB1 gene loci, and newborn's anthropometric profile at birth. Sixty-nine normoglycemic women were followed from the first trimester of pregnancy until delivery. Placental DNAm was quantified at 43 Cytosine-phosphate-Guanines (CpGs) at LDLR, LRP1, and SCARB1 gene loci using pyrosequencing: 4 CpGs were retained for further analysis. Maternal clinical data were collected at each trimester of pregnancy. Newborns' data were collected from medical records. Statistical models included minimally newborn sex and gestational and maternal age. Maternal total cholesterol changes during pregnancy (ΔT3-T1) were correlated with DNAm variations at LDLR (r = -0.32, p = 0.01) and LRP1 (r = 0.34, p = 0.007). DNAm at these loci was also correlated with newborns' cord blood triglyceride and leptin levels. Mediation analysis supports a causal relationship between maternal cholesterol changes, DNAm levels at LRP1 locus, and cord blood leptin concentration (pmediation = 0.02). These results suggest that LRP1 DNAm link maternal blood cholesterol changes in pregnancy and offspring adiposity at birth, which provide support for a better follow-up of blood lipids in pregnancy.

DMPK gene DNA methylation levels are associated with muscular and respiratory profiles in DM1.

OBJECTIVE: To assess the effects of dystrophia myotonica protein kinase (DMPK) DNA methylation (DNAme) epivariation on muscular and respiratory profiles in patients with myotonic dystrophy type 1 (DM1). METHODS: Phenotypes were assessed with standardized measures. Pyrosequencing of bisulfite-treated DNA was used to quantify DNAme levels in blood from 90 patients with DM1 (adult form). Modal CTG repeat length was assessed using small-pool PCR. The presence of Acil-sensitive variant repeats was also tested. RESULTS: DNAme levels upstream of the CTG expansion (exon and intron 11) were correlated with modal CTG repeat length (rs = -0.224, p = 0.040; rs = -0.317, p = 0.003; and rs = -0.241, p = 0.027), whereas correlations were observed with epivariations downstream of the CTG repeats (rs = 0.227; p = 0.037). The presence of a variant repeat was associated with higher DNAme levels at multiple CpG sites (up to 10% higher; p = 0.001). Stepwise multiple linear regression modeling showed that DNAme contributed significantly and independently to explain phenotypic variability in ankle dorsiflexor (3 CpGs: p = 0.001, 0.013, and 0.001), grip (p = 0.089), and pinch (p = 0.028) strengths and in forced vital capacity (2 CpGs: p = 0.002 and 0.021) and maximal inspiratory pressure (p = 0.012). CONCLUSIONS: In addition to the CTG repeat length, DMPK epivariations independently explain phenotypic variability in DM1 and could thus improve prognostic accuracy for patients.

Human high-density lipoprotein microtranscriptome is unique and suggests an extended role in lipid metabolism.

Aim: To comprehensively characterize the high-density lipoproteins (HDLs) microtranscriptome and to assess whether it is distinct from that of plasma and different between women and men. Methods: RNA was extracted from ultracentrifugation-purified HDLs and plasma from 17 healthy women and men couples, and libraries were sequenced on a HiSeq2500 platform. Results: On average, 310 ± 64 and 355 ± 31 miRNAs were detected (≥1 read per million) in HDLs and plasma, respectively. A total of 62 and 134 miRNAs were over-represented (e.g., miR-150-5p; fold change = 7.52; padj = 5.41 × 10-111) and under-represented (e.g., miR-22-3p; fold change = -5.28; padj = 2.11 × 10-154) in HDLs compared with plasma. These miRNAs were enriched in lipid metabolism and cellular processes-related pathways. Conclusion: HDLs exhibit a sex-independent miRNA profile distinct from that of plasma. These miRNAs may contribute to the HDLs' physiology.

PACE4 Undergoes an Oncogenic Alternative Splicing Switch in Cancer.

Inhibition of PACE4, a proprotein convertase that is overexpressed in prostate cancer, has been shown to block cancer progression in an androgen-independent manner. However, the basis for its overexpression and its growth-inhibitory effects are mitigated and uncertain. Here, we report that PACE4 pre-mRNA undergoes DNA methylation-sensitive alternative splicing of its terminal exon 3' untranslated region, generating an oncogenic, C-terminally modified isoform (PACE4-altCT). We found this isoform to be strongly expressed in prostate cancer cells, where it displayed an enhanced autoactivating process and a distinct intracellular routing that prevented its extracellular secretion. Together, these events led to a dramatic increase in processing of the progrowth differentiation factor pro-GDF15 as the first PACE4 substrate to be identified in prostate cancer. We detected robust expression of PACE4-altCT in other cancer types, suggesting that an oncogenic switch for this proenzyme may offer a therapeutic target not only in advanced prostate cancer but perhaps also more broadly in human cancer. Cancer Res; 77(24); 6863-79. ©2017 AACR.

Changes in high-density lipoprotein-carried miRNA contribution to the plasmatic pool after consumption of dietary trans fat in healthy men.

AIM: High-density lipoproteins (HDLs) are associated to cardioprotection and transport functional miRNAs in circulation. The aim of this study is to assess whether consumption of trans fatty acids (TFAs) modifies the HDL-carried miRNA concentration and their contribution to the plasmatic pool. METHODS: In a double-blind, randomized crossover controlled study, nine healthy men were fed each of three isoenergetic 4-week diets: first, rich in industrial TFAs; second, rich in TFAs from ruminants; third, low in TFAs. miRNAs were extracted from plasma and purified HDLs, and quantified by the real-time quantitative PCR (n = 87). RESULTS: Seven HDL-carried miRNAs contributed to more than 15% of the plasmatic pool. Although no significant difference in HDL-carried miRNA concentration among diets was observed after adjustment for multiple testing, changes in the contribution to the plasmatic pool between diets were observed for miR-124-3p, miR-375, miR-150-5p and miR-31-5p (p FDR < 0.05). These miRNAs were enriched in lipid metabolism pathways. CONCLUSION: These microtranscriptomic variants might reflect physiological changes in HDL functions in response to diet.