Sex Differences In mRNA Expression Research Articles

Androgen-Dependent Expression of CUX2 mRNA in the Pig Liver Is Associated with That of Drug Metabolizing Enzymes and Drug Transporters.

We previously identified androgen-dependent sex differences in the mRNA expression of drug metabolizing enzymes (DMEs), including CYPs, sulfotransferases and uridine 5'-diphospho-glucuronosyltransferases, and drug transporters in the pig liver and kidney. To elucidate the mechanism for such sex differences in pigs, we herein focused on the key regulators cut-like homeobox 2 (Cux2), B-cell lymphoma 6 (Bcl6), and signal transducer and activator of transcription 5b (Stat5b), which are reported to be responsible for the sex-biased gene expression of Cyps in the mouse liver. We used real-time RT-PCR to examine androgen-dependent sex differences in the mRNA levels of these regulators in the liver and kidney basically using Meishan and Landrace pigs. Significant sex differences (male > female) in the level of CUX2 mRNA were detected in the liver of both breeds, and levels were significantly decreased in males by castration and increased in castrated males and intact females by administering testosterone propionate. No such clear androgen-dependent sex differences in hepatic BCL6 or STAT5B mRNA expression were observed in either breed. In the kidney, androgen-dependent gene expression of these regulators was not observed. In the liver, CUX2 mRNA expression closely correlated with that of DMEs and drug transporters, which were previously shown to have androgen-dependent expression. Together, these findings demonstrate that hepatic CUX2 mRNA is expressed in an androgen-dependent manner, and strongly suggest that CUX2 plays a key role in the androgen-dependent gene expression of hepatic DMEs and drug transporters.

A role for PPARα in sex differences in cardiac hypertrophy

Heart failure remains a leading cause of death worldwide and treatment is complicated by sex differences in the development of this disease. While sex differences in cardiac hypertrophy are well documented, the mechanisms involved are poorly understood. The purpose of this study is to better understand the mechanisms that contribute to sex differences in cardiac hypertrophy. Male and female mice were treated with vehicle or Angiotensin II (AngII; 1.5 mg•kg-1•day-1) to induce cardiac hypertrophy and a systems biology analysis was performed on RNAseq data to identify pathways central to sex differences in cardiac hypertrophy. Cardiac hypertrophy was observed after 2 weeks of AngII and sex differences became apparent after 3 weeks. After 3 weeks of treatment ejection fraction (EF) in females was not different from control values (54% vs 56%). In males, however, EF dropped from 55% to 37%, which was significantly lower than EF in females after 3 weeks of treatment. RNA sequencing was performed on hearts and sex differences in mRNA expression at baseline and following hypertrophy were observed along with differences between baseline and hypertrophy within a sex. Sex differences in mRNA were substantial at baseline and reduced somewhat with hypertrophy, as the hypertrophic differences tended to overwhelm the sex differences. We selected genes that were significant for the sex-disease interaction, and mapped them to the protein-protein interaction network constructed using STRING data. This identified a network centered on PPARα. To examine the role of PPARα in sex differences in cardiac hypertrophy, we treated male and female mice with a PPARα inhibitor (GW6471; (4 mg•kg-1•day-1)) along with vehicle or AngII. The inhibitor blunted the development of hypertrophy in male hearts (+5% AngII+GW6471 vs +20% AngII), blocking sex differences in cardiac hypertrophy. These results suggest that PPARα contributes to sex differences in cardiac hypertrophy.

A Systems Biology Approach to Investigating Sex Differences in Cardiac Hypertrophy

BackgroundHeart failure preceded by hypertrophy is a leading cause of death, and sex differences in hypertrophy are well known, although the basis for these sex differences is poorly understood.Methods and ResultsThis study used a systems biology approach to investigate mechanisms underlying sex differences in cardiac hypertrophy. Male and female mice were treated for 2 and 3 weeks with angiotensin II to induce hypertrophy. Sex differences in cardiac hypertrophy were apparent after 3 weeks of treatment. RNA sequencing was performed on hearts, and sex differences in mRNA expression at baseline and following hypertrophy were observed, as well as within‐sex differences between baseline and hypertrophy. Sex differences in mRNA were substantial at baseline and reduced somewhat with hypertrophy, as the mRNA differences induced by hypertrophy tended to overwhelm the sex differences. We performed an integrative analysis to identify mRNA networks that were differentially regulated in the 2 sexes by hypertrophy and obtained a network centered on PPARα (peroxisome proliferator‐activated receptor α). Mouse experiments further showed that acute inhibition of PPARα blocked sex differences in the development of hypertrophy.ConclusionsThe data in this study suggest that PPARα is involved in the sex‐dimorphic regulation of cardiac hypertrophy.

Sex Differences in Blood Pressure and mRNA expression of Renal Sodium Transporters in Mice Under Normal Sodium Diet

We previously reported sex differences in blood pressure and the renal handling of sodium in mice consuming high salt diet (Fan L., et al FASEB J. 30, 731.6, 2016). The purpose of this study was to determine sex differences in blood pressure and mRNA expression of key renal sodium transporters in mice consuming normal chow and water for six weeks. Four‐week old intact male and female CD‐1 mice were purchased from Harlan, Inc. (ENVIGO) (Indianapolis, IN). Female and male mice (n = 5/group) were placed in metabolic cages and consumed normal chow (Harlan Teklad 2019) and water ad libitum for six weeks. Blood pressure in these mice was measured 5 days/week via the tail‐cuff technique (Kent Scientific CODA device). Separate mice in bins were maintained on the same dietary regimen and used for mRNA analysis of renal sodium transporters. Four mice in each group were sacrificed at the end of the first, third, fifth, and sixth weeks. Kidneys were removed, total RNA was extracted from renal cortical tissue and measured for quantity and quality, and this was followed by first‐strand cDNA synthesis. Real time qt‐PCR was performed using Sybr green and the RT2 Profiler™ PCR Custom Array system from SABiosciences (QIAGEN). Arrays contain primers of the following renal transporters ENaC (a, b, g subunits), NKCC2, NCC, NHE2, NHE3, SGLT, Agtr1a, and Atp1a1. Mean blood pressure (MBP, mmHg) averaged weekly was analyzed via two‐way ANOVA with repeated measures. Real time data was determined via ΔΔCt method and analyzed via RT2 Profiler™ PCR Array Data Analysis (Version 3.5) by SABiosciences. Results indicated that female kidneys expressed significantly higher mRNA levels of ENaC (b), NCC, Agtr1a, NHE2, and NHE3 in all four measured periods, higher levels of ENaC (a & g) and SGLT in three of the four periods, and higher NKCC2 levels in one period. Most expression levels were 2 fold or higher in female kidneys. Males had significantly higher MBP than females in week two (82.3 ± 3.5 vs 69.5 ± 2.0, respectively, p < 0.02) and had non‐significantly higher MBP in all other weeks. Both sexes showed increased MBP from week one to week six (female: 72.3 ± 1.1 to 82.2 ± 1.7, p < 0.07; and male: 79.9 ± 3.2 to 88.6 ± 3.2, p < 0.05). We conclude that female mice express higher mRNA levels of renal sodium transporters than male mice and maintain lower MBP than male mice. We suggest that both estrogen and testosterone play important roles in the sex differences in mRNA expression and blood pressure.Support or Funding InformationResearch supported by Oklahoma INBRE 8P20GM103447 Summer Research Program.

Sex Differences in mRNA Expression of Reduced Folate Carrier‐1, Folypolyformyl Glutamate Synthase, and γ‐Glutamyl Hydrolase in a Healthy Japanese Population

Sex differences in the prevalence of autoimmune diseases such as rheumatoid arthritis (RA) are well known, but little is known about those differences in relation to therapeutic response. Reduced folate carrier-1 (RFC-1), folypolyformyl glutamate synthase (FPGS), and γ-glutamyl hydrolase (GGH) are important transporters and enzymes that convert methotrexate (MTX) in the body. This study investigated the sex differences in mRNA expression of RFC-1, FPGS, and GGH in 190 unrelated healthy Japanese people. The genotypes and mRNA expression were determined using the real-time PCR method. Significant differences between men and women were observed in RFC-1, FPGS, and GGH mRNA expression. The mRNA expression of FPGS and GGH was greater in women than that in men, but the expression of RFC-1 was less in the former than the latter. In stratified analysis by genotype, significant differences in sex-specific mRNA expression were observed in G/G of FPGS, C/C of GGH 452, and C/C of GGH -401. All showed greater mRNA expression in women than in men. In the 5 single-nucleotide polymorphisms RFC-1 80G>A, RFC-1 -43T>C, FPGS 1994G>A, GGH 452C>T, and GGH -401C>T examined, the FPGS 1994 G/G (1.46-fold), GGH 452 C/C (2.16-fold), and GGH -401 C/C (2.68-fold) genotypes showed significantly higher mRNA expression in women than in men. Healthy Japanese adults in this study showed sex-specific differences in mRNA expression that differed among RFC-1, FPGS, and GGH. Therefore, the relationship between genetic polymorphisms and mRNA expression including sex differences might contribute to the variation in the efficacy/toxicity of MTX in patients with RA.

Effect of sex differences on human MEF2 regulation during endurance exercise

Women exhibit an enhanced capability for lipid metabolism during endurance exercise compared with men. The underlying regulatory mechanisms behind this sex-related difference are not well understood but may comprise signaling through a myocyte enhancer factor 2 (MEF2) regulatory pathway. The primary purpose of this study, therefore, was to investigate the protein signaling of MEF2 regulatory pathway components at rest and during 90 min of bicycling exercise at 60% Vo(2peak) in healthy, moderately trained men (n = 8) and women (n = 9) to elucidate the potential role of these proteins in substrate utilization during exercise. A secondary purpose was to screen for mRNA expression of MEF2 isoforms and myogenic regulatory factor (MRF) family members of transcription factors at rest and during exercise. Muscle biopsies were obtained before and immediately after exercise. Nuclear AMP-activated protein kinase-alpha (alphaAMPK) Thr(172) (P < 0.001), histone deacetylase 5 (HDAC5) Ser(498) (P < 0.001), and MEF2 Thr (P < 0.01) phosphorylation increased with exercise. No significant sex differences were observed at rest or during exercise. At rest, no significant sex differences were observed in mRNA expression of the measured transcription factors. mRNA for transcription factors MyoD, myogenin, MRF4, MEF2A, MEF2C, MEF2D, and peroxisome proliferator-activated receptor-gamma coactivator 1alpha (PGC1alpha) were significantly upregulated by exercise. Of these, MEF2A mRNA increased 25% specifically in women (P < 0.05), whereas MEF2D mRNA tended to increase in men (P = 0.11). Although minor sex differences in mRNA expression were observed, the main finding of the present study was the implication of a joint signaling action of AMPK, HDAC5, and PGC1alpha on MEF2 in the immediate regulatory response to endurance exercise. This signaling response was independent of sex.

Secretoglobins: Sexually Dimorphic Expression of Androgen-Binding Protein mRNA in Mouse Lacrimal Glands

This study was conducted to seek sex differences in mRNA expression in normal mouse lacrimal glands. Gene expression differences in the lacrimal gland may contribute to susceptibility to lacrimal gland or ocular surface disease. A differential display analysis was performed on poly(A)+ RNA isolated from male and female Swiss Webster mouse exorbital lacrimal glands. Four potential gender-specific products were subcloned and sequenced. Full-length cDNAs of each product were obtained using RACE-PCR. 32P-labeled fragments of each clone were hybridized to a blot of male and female mouse poly(A)+ RNA isolated from harderian, lacrimal, submandibular, sublingual, and parotid glands and the liver. GenBank database alignments indicated that the four clones were members of the secretoglobin family. The most closely related sequences were the mouse salivary androgen-binding protein (ABP) subunits alpha, beta, and gamma. We named the four lacrimal clones the delta, epsilon, zeta, and eta subunits of ABP. Northern blot analysis showed that mRNAs for each of these four ABP subunits were lacrimal-gland-specific. The delta and zeta subunits of ABP were expressed primarily in male mouse lacrimal gland. Sequence attributes predict that the ABP subunits expressed in lacrimal glands comprise proteins that are secreted in tears. These data imply compositional differences in ABPs secreted by mouse lacrimal and submandibular glands, and in ABPs secreted by male and female mouse lacrimal glands.