Fetal Muscle Research Articles

Maternal Obesity Alters Offspring Muscle Mitochondrial Function in Nonhuman Primates

Offspring of obese mothers have increased risk for early obesity and insulin resistance. Impairment in mitochondrial (MT) function may be a primary mechanism leading to insulin resistance. This study seeks to determine if maternal western‐style diet (WSD) or obesity alone alter fetal muscle MT function and if this persists at 3yrs. Adult Japanese Macaques were chronically (>2yr) fed a control (CON) or WSD. Some WSD‐induced obese dams were switched to CON at the start of pregnancy (REV). Fetal samples were collected at gestational day 130/165. Offspring carried to term were weaned to a CON or WSD after exposure to either gestational WSD (WSD/WSD;WSD/CON) or CON (CON/WSD;CON/CON). Fetal and juvenile gastrocnemius fibers were assayed for MT function in the presence of carbohydrate (CHO) or palmitate (PALM) using high‐resolution respirometry. Fetal respiratory control ratios (RCR) decreased in WSD and REV, demonstrating 24% increased uncoupling. CHO‐stimulated state 3 respiration was reduced by 20% (p<0.01) in WSD and REV, but neither were significantly decreased in PALM. In juveniles, RCR was doubled in CON/WSD vs. CON/CON, but this increase did not occur in WSD/WSD. Likewise, CHO coupling control ratio was doubled in CON/CON vs. CON/WSD (p<0.05), but not in WSD/WSD. Maternal obesity with or without WSD reduces MT function and metabolic flexibility in fetal muscle. Inflexibility persists in the postnatal period, but only when lean offspring are challenged with WSD. Our data suggest that exposure to maternal obesity alters cellular systems responsible for MT adaptation to WSD and may contribute to increased risk of metabolic disease.Funding: NIH DK090964

Chronic Hypoxia Alters the Response of Fetal Ovine Middle Cerebral Arteries to Endothelin‐1 (ET‐1)

This study explores the hypothesis that chronic hypoxia alters the expression and intracellular coupling of endothelin receptors to induce phenotypic transformations of smooth muscle cells within the arteries of fetal cerebrovasculature. Endothelium‐denuded middle cerebral arteries (MCAs) harvested from term fetuses of pregnant adult sheep kept at sea level or 3820m for 110 days were used in contractility experiments or cultured with ET‐1 and various kinase inhibitors. Chronic hypoxia had no effect on plasma levels of ET‐1 but altered contractile responses to ET‐1 and increased ETA receptor expression in fetal MCAs. ET‐1 treatment increased arterial thicknesses in both normoxic and hypoxic arteries. Organ culture of MCAs with ET‐1 decreased colocalization of MLCK and α‐actin and this effect was attenuated by chronic hypoxia. ET‐1 also decreased MLC20 and MLCK colocalization, but this effect was similar in normoxic and hypoxic arteries. The effects of ET‐1 on colocalization were reversed by inhibitors of either PKC (7 µM chelerythrine) or p38 (10 µM SB203580) in both normoxic and hypoxic arteries. From these results we conclude that chronic hypoxia modulates phenotypic responses of fetal cerebrovascular smooth muscle to ET‐1 through elevated expression of ET‐1 receptors, which act downstream through PKC and p38 dependent pathways on contractile protein expression.This work was supported by National Institutes of Health Grants HL‐54120, HD‐31266, HL‐64867, and NS‐076945 and the Loma Linda University School of Medicine.

Arterial Smooth Muscle Proliferative Responses to ET‐1 are Subject to Hypoxic Pre‐conditioning in Term Fetal Lamb Arteries

This study explores the hypothesis that the vascular proliferative response to ET-1 is subject to hypoxic pre-conditioning in term fetal arteries. To test this idea, pregnant ewes were maintained at sea level or at an altitude of 3,820 m for the final 110 days of gestation. Endothelium-denuded carotid arteries harvested from full-term fetuses were cultured in serum-starved media with 3, 10 and 30 nM of ET-1 in normoxic (21% O2) and hypoxic (12% O2) chambers for 48 hours. Proliferative responses were quantified as changes in the colocalization of Non-Muscle (NM) and Smooth Muscle (SM) Myosin Heavy Chain with smooth muscle alpha-actin (SMaA). In normoxic fetal arteries cultured under normoxic conditions (FN-N), ET-1 produced a modest concentration-dependent increase in NM-SMaA colocalization and this effect was depressed 65% in arteries cultured under hypoxic conditions (FN-H). In hypoxic fetal arteries cultured under normoxic conditions (FH-N), responses to normoxic culture were not different than observed in the FN-N group. In hypoxic fetal arteries cultured under hypoxic conditions (FH-H), however, responses to ET-1 were attenuated only 22%. Corresponding numbers for SM-SMaA colocalization reflected a 46% depression in FN arteries, but 25% depression in FH arteries. Together, these results demonstrate that hypoxic acclimatization enhances the ability of smooth muscle to regulate contractile protein organization in response to ET-1-induced proliferation, suggesting that hypoxic preconditioning involves intracellular changes in fetal arterial smooth muscle. This work was supported by National Institutes of Health Grants HL-54120, HD-31266, HL-64867, and NS-076945 and the Loma Linda University School of Medicine.

Oncofetal expression of Wilms’ tumor 1 (WT1) protein in human fetal, adult and neoplastic skeletal muscle tissues

There is increasing evidence that WT1 protein expression is found not only at nuclear, but also at cytoplasmic, level in several developing and neoplastic tissues. In order to better understand the possible role of WT1 protein in human skeletal myogenesis and oncogenesis of rhabdomyosarcoma, we assessed immunohistochemically its comparative expression in a large series of human developing, adult and neoplastic skeletal muscle tissues. The present study shows that WT1 protein is developmentally expressed in the cytoplasm of human myoblasts from the 6 weeks of gestational age. This expression was maintained in the myotubes of developing muscles of the trunk, head, neck, and extremities, while it was down-regulated in fetal skeletal fibers from 20 weeks of gestational age as well as in adult normal skeletal muscle. Notably, WT1 immunostaining disappeared from rhabdomyomas, whereas it was strongly and diffusely re-expressed in all cases (27/27) of embryonal and alveolar rhabdomyosarcoma. The comparative evaluation of the immunohistochemical findings revealed that WT1 cytoplasmic expression in rhabdomyosarcoma may represent an ontogenetic reversal, and this nuclear transcription factor can also be considered an oncofetal protein which can be exploitable as an additional, highly sensitive immunomarker, together with desmin, myogenin and MyoD1, of this tumor. Moreover, our observations support the rationale for the use of WT1 protein-based target therapy in high risk rhabdomyosarcomas in children and adolescents.

Systematic identification and characterization of long intergenic non-coding RNAs in fetal porcine skeletal muscle development.

Long intergenic non-coding RNAs (lincRNAs) play important roles in many cellular processes. Here, we present the first systematic identification and characterization of lincRNAs in fetal porcine skeletal muscle. We obtained a total of 55.02 million 90-bp paired-end reads and assembled 54,550 transcripts using cufflinks. We developed a pipeline to identify 570 multi-exon lincRNAs by integrating a set of previous approaches. These putative porcine lincRNAs share many characteristics with mammalian lincRNAs, such as a relatively short length, small number of exons and low level of sequence conservation. We found that the porcine lincRNAs were preferentially located near genes mediating transcriptional regulation rather than those with developmental functions. We further experimentally analyzed the features of a conserved mouse lincRNA gene and found that isoforms 1 and 4 of this lincRNA were enriched in the cell nucleus and were associated with polycomb repressive complex 2 (PRC2). Our results provide a catalog of fetal porcine lincRNAs for further experimental investigation of the functions of these genes in the skeletal muscle developmental process.

Porcine EEF1A1 and EEF1A2 genes: genomic structure, polymorphism, mapping and expression.

Eukaryotic translation elongation factor 1 alpha (EEF1A) plays a key role in protein synthesis. In higher vertebrates EEF1A occurs in two isoforms, EEF1A1 and EEF1A2, encoded by distinct genes. The purpose of this study was to compare the two porcine genes as for the genomic sequence, gene organization and mRNA expression in different tissues, as well as to search for polymorphism and chromosomal assignment. Standard methods of DNA and mRNA analysis were used. We determined the complete genomic sequence of the porcine EEF1A1 and EEF1A2 genes. The two genes differ in the lengths of transcription units (3102 and 8588 bp, respectively), but have similar genomic organization and their coding sequences are highly similar (78% identity of coding sequences and 92.4% identity of amino acid sequences). Several polymorphisms in the two genes were detected. EEF1A1 and EEF1A2 were mapped to SSC1p11.1 and SSC17q23.3, respectively. mRNA of EEF1A1 was expressed in all studied tissues (the highest expression was in 44-day fetal muscle and low expression in adult liver and brain), while EEF1A2 was expressed only in skeletal-muscle, tongue, heart, diaphragm and brain tissues. EEF1A2 was not expressed in fetal muscle tissue (44 days). In this paper results are provided on genomic sequences, genomic organization, polymorphism, chromosomal assignment and spatial and temporal expressions of the porcine EEF1A1 and EEF1A2 genes. Novel polymorphisms were described in both genes. Porcine EEF1A2 was studied for the first time.

Influence of the gestational stage on the clinical course, lesional development and parasite distribution in experimental ovine neosporosis.

Neospora caninum is considered one of the main causes of abortion in cattle, yet recent studies have also emphasised its relevance as an abortifacient in small ruminants. In order to gain deeper insight into the pathogenesis of ovine neosporosis, pregnant ewes were intravenously inoculated with 106 tachyzoites of the Nc-Spain7 isolate at days 40, 90 or 120 of gestation. Infection during the first term resulted in the death of all foetuses between days 19 and 21 post-infection, showing mainly necrotic lesions in foetal liver and the highest parasite DNA detection and burden in both placenta and foetal viscera. After infection at day 90, foetal death was also detected in all ewes, although later (34–48 days post-infection). In this group, lesions were mainly inflammatory. Foetal livers showed the lowest frequency of lesions, as well as the lowest parasite detection and burden. All ewes infected at day 120 delivered viable lambs, although 3 out of 9 showed weakness and recumbency. Neospora DNA was detected in all lambs but one, and parasite burden was similar to that observed in day 90 group. Lesions in this group showed more conspicuous infiltration of inflammatory cells and higher frequency in foetal brain and muscle when compared to both previous groups. These results highlight the crucial role that the stage of gestation plays on the course of ovine neosporosis, similar to that reported in bovine neosporosis, and open the doors to consider sheep as a valid model for exogenous transplacental transmission for ruminant neosporosis.Electronic supplementary materialThe online version of this article (doi:10.1186/s13567-014-0139-y) contains supplementary material, which is available to authorized users.

The influence of human fetal mesenchymal stem cells on glioma cell proliferation. The consequence of cellular crosstalk

The effect of mesenchymal stem cells (MSCs) on the growth of various tumors is ambiguous. MSCs derived from different tissues stimulate growth of some tumor types and exert antitumor effects on the other. Several recent reports have shown that crosstalk between tumor cells and MSCs contribute to these effects. The aim of this work was to study the effects of MSCs derived from fetal tissues on the proliferative activity of glioma cells in conditions of prolonged co-cultivation. We have analyzed the proliferative activity of glioma cells exposed to conditioned medium (CM) from MSCs derived from fetal bone marrow (FetMSC) and fetal muscle (M-FetMSC) as well as to CM from co-cultivation of the fetal MSCs with U251MG glioma cells. As a comparison, the influence of CM from adult dermal fibroblasts (DFs) was examined in identical experiments. Using MTT assay, we have found that CM from both the fetal MSCs and adult DFs (without their co-culturing with glioma cells) had no effect on U251MG and A172 glioma cell proliferation. However, CM from early co-cultures (3-9 days) of U251MG cells with FetMSC or M-FetMSC exerted stimulatory effect on U251MG cell proliferation up to 2.3-fold increase, while CM obtained later from the same co-cultures (15-21 days) had inhibitory effect on the proliferation up to arrest of cell division. Analogous experiments with adult DFs have revealed a persistent stimulation of U251MG cell proliferative activity for all 21 days of co-culturing. Immunofluorescence analysis revealed a reduction in the expression of cell cycle protein cyclin D1 in U251MG cells after their treatment with CM taken from 21-days co-cultures of U251MG cells with FetMSC or M-FetMSC. In contrast, CM from 21-days co-cultures of U251MG cells with DFs did not decrease the expression of cyclin D1. These results show that fetal MSCs have dual effect on glioma cell proliferation. In spite of the earlier stimulatory effect on the proliferative activity, prominent inhibition of glioma cell proliferation was observed after three week co-culturing of glioma cells with fetal MSCs. This is the first report demonstrating reversion of tumor cell proliferative program during co-culturing with MSCs for a long time. These data suggest that CM obtained at different time points of cell co-culturing can be used in the modeling of prolonged cellular crosstalk.

Vitamin D attenuates cytokine-induced remodeling in human fetal airway smooth muscle cells.

Asthma in the pediatric population remains a significant contributor to morbidity and increasing healthcare costs. Vitamin D3 insufficiency and deficiency have been associated with development of asthma. Recent studies in models of adult airway diseases suggest that the bioactive Vitamin D3 metabolite, calcitriol (1,25-dihydroxyvitamin D3 ; 1,25(OH)2 D3 ), modulates responses to inflammation; however, this concept has not been explored in developing airways in the context of pediatric asthma. We used human fetal airway smooth muscle (ASM) cells as a model of the early postnatal airway to explore how calcitriol modulates remodeling induced by pro-inflammatory cytokines. Cells were pre-treated with calcitriol and then exposed to TNFα or TGFβ for up to 72 h. Matrix metalloproteinase (MMP) activity, production of extracellular matrix (ECM), and cell proliferation were assessed. Calcitriol attenuated TNFα enhancement of MMP-9 expression and activity. Additionally, calcitriol attenuated TNFα and TGFβ-induced collagen III expression and deposition, and separately, inhibited proliferation of fetal ASM cells induced by either inflammatory mediator. Analysis of signaling pathways suggested that calcitriol effects in fetal ASM involve ERK signaling, but not other major inflammatory pathways. Overall, our data demonstrate that calcitriol can blunt multiple effects of TNFα and TGFβ in developing airway, and point to a potentially novel approach to alleviating structural changes in inflammatory airway diseases of childhood.

MiRNA expression in control and FSHD fetal human muscle biopsies.

BackgroundFacioscapulohumeral muscular dystrophy (FSHD) is an autosomal-dominant disorder and is one of the most common forms of muscular dystrophy. We have recently shown that some hallmarks of FSHD are already expressed in fetal FSHD biopsies, thus opening a new field of investigation for mechanisms leading to FSHD. As microRNAs (miRNAs) play an important role in myogenesis and muscle disorders, in this study we compared miRNAs expression levels during normal and FSHD muscle development.MethodsMuscle biopsies were obtained from quadriceps of both healthy control and FSHD1 fetuses with ages ranging from 14 to 33 weeks of development. miRNA expression profiles were analyzed using TaqMan Human MicroRNA Arrays.ResultsDuring human skeletal muscle development, in control muscle biopsies we observed changes for 4 miRNAs potentially involved in secondary muscle fiber formation and 5 miRNAs potentially involved in fiber maturation. When we compared the miRNA profiles obtained from control and FSHD biopsies, we did not observe any differences in the muscle specific miRNAs. However, we identified 8 miRNAs exclusively expressed in FSHD1 samples (miR-330, miR-331-5p, miR-34a, miR-380-3p, miR-516b, miR-582-5p, miR-517* and miR-625) which could represent new biomarkers for this disease. Their putative targets are mainly involved in muscle development and morphogenesis. Interestingly, these FSHD1 specific miRNAs do not target the genes previously described to be involved in FSHD.ConclusionsThis work provides new candidate mechanisms potentially involved in the onset of FSHD pathology. Whether these FSHD specific miRNAs cause deregulations during fetal development, or protect against the appearance of the FSHD phenotype until the second decade of life still needs to be investigated.

Altered fetal skeletal muscle nutrient metabolism following an adverse in utero environment and the modulation of later life insulin sensitivity.

The importance of the in utero environment as a contributor to later life metabolic disease has been demonstrated in both human and animal studies. In this review, we consider how disruption of normal fetal growth may impact skeletal muscle metabolic development, ultimately leading to insulin resistance and decreased insulin sensitivity, a key precursor to later life metabolic disease. In cases of intrauterine growth restriction (IUGR) associated with hypoxia, where the fetus fails to reach its full growth potential, low birth weight (LBW) is often the outcome, and early in postnatal life, LBW individuals display modifications in the insulin-signaling pathway, a critical precursor to insulin resistance. In this review, we will present literature detailing the classical development of insulin resistance in IUGR, but also discuss how this impaired development, when challenged with a postnatal Western diet, may potentially contribute to the development of later life insulin resistance. Considering the important role of the skeletal muscle in insulin resistance pathogenesis, understanding the in utero programmed origins of skeletal muscle deficiencies in insulin sensitivity and how they may interact with an adverse postnatal environment, is an important step in highlighting potential therapeutic options for LBW offspring born of pregnancies characterized by placental insufficiency.

Lean and obese pig breeds exhibit differences in prenatal gene expression profiles of muscle development

Muscle development in domesticated animals is important for meat production. Furthermore, intramuscular fat content is an important trait of meat intended for consumption. Here, we examined differences in the expression of factors related to myogenesis, adipogenesis and skeletal muscle growth during fetal muscle development of lean (Yorkshire) and obese (Chenghua) pig breeds. At prenatal days 50 (d50) and 90 (d90), muscles and sera were collected from pig fetuses. Histology revealed larger diameters and numbers of myofibers in Chenghua pig fetuses than those in Yorkshire pig fetuses at d50 and d90. Yorkshire fetuses had higher serum concentrations of myostatin (d90), a negative regulator for muscle development, and higher mRNA expression of the growth hormone receptor Ghr (d90), myogenic MyoG (d90) and adipogenic LPL (d50). By contrast, Chenghua fetuses exhibited higher serum concentration of growth hormone (d90), and higher mRNA expression of myogenic MyoD (d90) as well as adipogenic PPARG and FABP4 (d50). Our results revealed distinct expression patterns in the two pig breeds at each developmental stage before birth. Compared with Chenghua pigs, development and maturation of fetal skeletal muscles may occur earlier in Yorkshire pigs, but the negative regulatory effects of myostatin may suppress muscle development at the later stage.

Delayed muscle development in small pig fetuses around birth cannot be rectified by maternal early feed restriction and subsequent overfeeding during gestation

Intrauterine variations in nutrient allowance can alter body composition and tissue features of the porcine offspring around birth. This study aimed to determine the effects of fetal weight variations between littermates and of maternal dietary regimen during gestation on fetal muscle traits just before birth. Fourteen pregnant gilts were reared under a conventional (control, CTL; n=7) or an experimental (treatment, TRT; n=7) dietary regimen during gestation. The dietary treatment provided 70% of the protein and digestible energy contents of the CTL diet during the first 70 days of gestation and then, 115% of the protein and digestible energy contents up to farrowing. At 110 days of gestation, sows were sacrificed and one fetus having a low (824±140 g) and one having a normal (1218±192 g) BW per litter were sampled. Irrespective of maternal dietary regimen, the longissimus muscle of the small fetuses exhibited higher expression levels of DLK1/Pref1 and NCAM1/CD56, two genes known to be downregulated during normal skeletal muscle development. Expression levels of the embryonic isoform of the myosin heavy chain (MyHC), both at the mRNA and at the protein levels, were also higher in small fetuses. In addition, the ratios of perinatal to embryonic and of adult fast to developmental MyHC isoforms were generally lower in light fetuses compared with their medium-weight littermates. These modifications suggest a delayed myofiber development in spontaneous growth-retarded fetuses. Finally, GLUT1 was expressed to a lesser extent in the muscle of small v. normal fetuses, suggesting decreased ability for glucose uptake in muscle. Initial feed restriction and subsequent overfeeding of sows during gestation led to a lower expression of the myogenic factor MYOD1, a prerequisite for myogenic initiation in skeletal muscle. This maternal strategy was also associated with a lower expression level of insulin-like growth factor 1 receptor (IGFR) but an upregulation of IGF2. This suggests an altered susceptibility of muscle cells to IGFs’ signal in fetuses from treated sows. Altogether, intrauterine growth restriction impaired fetal muscle development, and restricted feeding followed by overfeeding of gestating sows did not allow small fetuses to recover normal contractile and metabolic characteristics.

Calcium Sparklets in Intact Mammalian Skeletal Muscle Fibers Expressing the Embryonic CaV1.1 Splice Variant

The embryonic splice variant of the voltage-gated L-type calcium channel (CaV1.1e) displays an altered voltage-dependence and gating kinetics as compared to that expressed in adult skeletal muscle. Because the adult CaV1.1a only opens slowly at strong depolarizations, its contribution as a source of calcium influx during action potentials is negligible. In contrast, calcium influx through the embryonic CaV1.1e substantially contributes to depolarization-induced calcium transients in fetal muscles and in cultured myotubes. In a genetically modified mouse (CaV1.1αE29), which exclusively expresses the embryonic CaV1.1e variant also in adult muscle the calcium influx component is maintained throughout life. Utilizing this mouse model, calcium release events - calcium sparklets - were recorded in enzymatically isolated, intact adult skeletal muscle fibers from the m. flexor digitorum longus using the fluorescent calcium probe fluo-8 and the fast confocal scanner (ZeissLive) in the x-y mode. While control animals did not display such events, CaV1.1αE29 mice spontaneously generated sparklets with a frequency of 9.2∗10-4±6∗10-4 Hz/μm2 (19 fibers; mean±SEM). The role of external calcium as the trigger was tested by either removing calcium from the external solution or by the application of 5μM nizoldipine to block the calcium current through CaV1.1e. Both interventions resulted in a complete loss of the events. Identified sparklets (n=311) were characterized by an average amplitude (αF/F0) of 0.287±0.005, a full-width at half-maximum of 3.05±0.05 µm, and duration of 235±4 ms, clearly different from the properties of calcium sparks on saponin-permeabilized adult mammalian skeletal muscle fibers. These findings indicate that the sustained expression of the CaV1.1e splice variant gives rise to spontaneous calcium entry events (sparklets) in adult muscle fibers and that their properties are distinct from calcium sparks arising from ryanodine receptors. Support: OTKA-NN107765, FWF P23479, W1101, TAMOP-4.2.4.A./2-11-1-2012-0001.

Morphometric study of the latissimus dorsi muscle in human fetuses

Morphometric study of the latissimus dorsi muscle in human fetuses

Transcriptome analysis of skeletal muscle at prenatal stages in Polled Dorset versus Small-tailed Han sheep.

The objectives of the present study were to identify additional genes that may play important roles in the regulation of skeletal muscle growth and development, and to provide fundamental information for understanding the underlying molecular mechanisms. Eighteen cDNA libraries were constructed from the longissimus muscle of Polled Dorset (PD) and Small-tailed Han (SH) fetuses. To reveal the differences between the two species, we analyzed the differences in gene expression in 60-, 90- and 120-day fetal skeletal muscle by applying Agilent ovine genome-wide microarray. In this study, we obtained 17,704 genes using a chip containing 39,242 probes. There were 88 differentially expressed genes in the 60-day group (P < 0.05), 128 genes in the 90-day group (P < 0.05), and 340 genes in the 120-day group (P < 0.05) between the two breeds. The differentially expressed genes were grouped in different GO categories and signaling pathways. These results suggested that there are many genetic differences in the muscle growth and development transcriptomes between these two breeds. This study laid the foundation for future genomic research in sheep.

Myogenesis in small and large ovine fetuses at three stages of pregnancy

Perturbations of the prenatal environment may influence fetal muscle development. This study investigated muscle cellularity and mRNA abundance of myogenic genes in fetal sheep divergent in their patterns of growth. Muscle samples were obtained from small and large fetuses on Days 50, 92 and 133 of pregnancy. Number of myofibres in the semitendinosus muscle increased between Day 92 and 133 of pregnancy, but did not differ between small and large fetuses at either stage of pregnancy. The semitendinosus of small fetuses had smaller cross-sectional areas of myofibres than did those of their large counterparts on Day 133 of pregnancy. The semitendinosus of small fetuses also had lower DNA concentration on Day 92 and lower protein concentration on Day 133 than did those of large fetuses. The mRNA levels of the myogenic regulatory factors (MRFs), myostatin, the insulin-like growth factors and embryonic myosin in fetal muscles varied with the stage of development, but no differences occurred in response to divergent fetal growth. Myostatin mRNA was more abundant in the semitendinosus than in the supraspinatus muscle on Days 92 and 133, as were myogenic regulatory factors, myf-5, myf-6 and follistatin mRNA on Day 133. The results indicated that muscle growth but not the number of myofibres in fetal sheep is modified by restricted fetal growth, and that genes that regulate muscle development are affected by the stage of development in an anatomical muscle-specific manner.

288: Synthetic double stranded RNA increases chemokine expression in human fetal airway smooth muscle cells

288: Synthetic double stranded RNA increases chemokine expression in human fetal airway smooth muscle cells

Hyperoxia-induced changes in estradiol metabolism in postnatal airway smooth muscle.

Supplemental oxygen, used to treat hypoxia in preterm and term neonates, increases the risk of neonatal lung diseases, such as bronchopulmonary dysplasia (BPD) and asthma. There is a known sex predilection for BPD, but the underlying mechanisms are not clear. We tested the hypothesis that altered, local estradiol following hyperoxia contributes to pathophysiological changes observed in immature lung. In human fetal airway smooth muscle (fASM) cells exposed to normoxia or hyperoxia, we measured the expression of proteins involved in estrogen metabolism and cell proliferation responses to estradiol. In fASM cells, CYP1a1 expression was increased by hyperoxia, whereas hyperoxia-induced enhancement of cell proliferation was blunted by estradiol. Pharmacological studies indicated that these effects were attributable to upregulation of CYP1a1 and subsequent increased metabolism of estradiol to a downstream intermediate 2-methoxyestradiol. Microarray analysis of mouse lung exposed to 14 days of hyperoxia showed the most significant alteration in CYP1a1 expression, with minimal changes in expression of five other genes related to estrogen receptors, synthesis, and metabolism. Our novel results on estradiol metabolism in fetal and early postnatal lung in the context of hyperoxia indicate CYP1a1 as a potential mechanism for the protective effect of estradiol in hyperoxia-exposed immature lung, which may help explain the sex difference in neonatal lung diseases.

Genome-wide DNA methylation profiles and their relationships with mRNA and the microRNA transcriptome in bovine muscle tissue (Bos taurine).

DNA methylation is a key epigenetic modification in mammals and plays important roles in muscle development. We sampled longissimus dorsi muscle (LDM) from a well-known elite native breed of Chinese Qinchuan cattle living within the same environment but displaying distinct skeletal muscle at the fetal and adult stages. We generated and provided a genome-wide landscape of DNA methylomes and their relationship with mRNA and miRNA for fetal and adult muscle studies. Integration analysis revealed a total of 77 and 1,054 negatively correlated genes with methylation in the promoter and gene body regions, respectively, in both the fetal and adult bovine libraries. Furthermore, we identified expression patterns of high-read genes that exhibit a negative correlation between methylation and expression from nine different tissues at multiple developmental stages of bovine muscle-related tissue or organs. In addition, we validated the MeDIP-Seq results by bisulfite sequencing PCR (BSP) in some of the differentially methylated promoters. Together, these results provide valuable data for future biomedical research and genomic and epigenomic studies of bovine skeletal muscle that may help uncover the molecular basis underlying economically valuable traits in cattle. This comprehensive map also provides a solid basis for exploring the epigenetic mechanisms of muscle growth and development.