Molecular characterization and expression patterns of Lbx1 in porcine skeletal muscle

Global analysis of the association between pig muscle fatty acid composition and gene expression using RNA-Seq

Fatty acids (FAs) play an essential role as mediators of cell signaling and signal transduction, affecting metabolic homeostasis and determining meat quality in pigs. However, FAs are transformed by the action of several genes, such as those encoding desaturases and elongases of FAs in lipogenic tissues. The aim of the current work was to identify candidate genes, biological processes, and pathways involved in the modulation of intramuscular FA profile from longissimus dorsi muscle. FA profile by gas chromatography of methyl esters and gene expression by RNA-Seq were determined in 129 Iberian × Duroc backcrossed pigs. An association analysis between the muscle transcriptome and its FA profile was performed, followed by a concordance and functional analysis. Overall, a list of well-known (e.g., PLIN1, LEP, ELOVL6, SC5D, NCOA2, ACSL1, MDH1, LPL, LGALS12, TFRC, GOT1, and FBP1) and novel (e.g., TRARG1, TANK, ENSSSCG00000011196, and ENSSSCG00000038429) candidate genes was identified, either in association with specific or several FA traits. Likewise, several of these genes belong to biological processes and pathways linked to energy, lipid, and carbohydrate metabolism, which seem determinants in the modulation of FA compositions. This study can contribute to elucidate the complex relationship between gene expression and FA profile in pig muscle.

Wt1 Positive dB4 Neurons in the Hindbrain Are Crucial for Respiration

Central pattern generator (CPG) networks coordinate the generation of rhythmic activity such as locomotion and respiration. Their development is driven by various transcription factors, one of which is the Wilms tumor protein (Wt1). It is present in dI6 neurons of the mouse spinal cord, and involved in the coordination of locomotion. Here we report about the presence of Wt1 in neurons of the caudoventral medulla oblongata and their impact on respiration. By employing immunohistofluorescence staining, we were able to characterize these Wt1 positive (+) cells as dB4 neurons. The temporal occurrence of Wt1 suggests a role for this transcription factor in the differentiation of dB4 neurons during embryonic and postnatal development. Conditional knockout of Wt1 in these cells caused an altered population size of V0 neurons already in the developing hindbrain, leading to a decline in the respiration rate in the adults. Thereby, we confirmed and extended the previously proposed similarity between dB4 neurons in the hindbrain and dI6 neurons of the spinal cord, in terms of development and function. Ablation of Wt1+ dB4 neurons resulted in the death of neonates due to the inability to initiate respiration, suggesting a vital role for Wt1+ dB4 neurons in breathing. These results expand the role of Wt1 in the CNS and show that, in addition to its function in differentiation of dI6 neurons, it also contributes to the development of dB4 neurons in the hindbrain that are critically involved in the regulation of respiration.

Comprehensive Profiles of mRNAs and miRNAs Reveal Molecular Characteristics of Multiple Organ Physiologies and Development in Pigs

The pig (Sus scrofa) is not only an important livestock animal but also widely used as a biomedical model. However, the understanding of the molecular characteristics of organs and of the developmental skeletal muscle of the pig is severely limited. Here, we performed a comprehensive transcriptome profiling of mRNAs and miRNAs across nine tissues and three skeletal muscle developmental stages in the Guizhou miniature pig. The reproductive organs (ovary and testis) had greater transcriptome complexity and activity than other tissues, and the highest transcriptome similarity was between skeletal muscle and heart (R = 0.79). We identified 1,819 mRNAs and 96 miRNAs to be tissue-specific in nine organs. Testis had the largest number of tissue-specific mRNAs (992) and miRNAs (40). Only 15 genes and two miRNAs were specifically expressed in skeletal muscle and fat, respectively. During postnatal skeletal muscle development, the mRNAs associated with focal adhesion, Notch signaling, protein digestion, and absorption pathways were up-regulated from D0 to D30 and then down-regulated from D30 and D240, while genes with opposing expression patterns were significantly enriched in the oxidative phosphorylation and proteasome pathways. The miRNAs mainly regulated genes associated with insulin, Wnt, fatty acid biosynthesis, Notch, MAPK, TGF-beta, insulin secretion, ECM-receptor interaction, focal adhesion, and calcium signaling pathways. We also identified 37 new miRNA-mRNA interaction pairs involved in skeletal muscle development. Overall, our data not only provide a rich resource for understanding pig organ physiology and development but also aid the study of the molecular functions of mRNA and miRNA in mammals.

The association of rs11190870 near LBX1 with the susceptibility and severity of AIS, a meta-analysis

BACKGROUND

Adolescent idiopathic scoliosis (AIS) is the most common structural deformity of the spine. Genetics constitute largely to AIS, and the rs11190870 polymorphism has the potential for use in public health and clinical settings as a predictor of AIS risk. The aim of the present meta-analysis was to provide exhaustive evidence to evaluate the association of rs11190870 with the susceptibility and severity of adolescent idiopathic scoliosis (AIS) in multiple ethnic groups and different genders.

MATERIALS AND METHODS

The professional databases, including PubMed, Embase, Social Sciences Citation Index, CINAHL, and International Bibliography of the Social Sciences, were searched from 1966 to October 2015. No language restriction was applied. Reference lists of all the selected articles were hand-searched for any additional studies. Three authors independently extracted data from all eligible studies. The data were analyzed by meta-analysis using fixed-effects or random-effects models with mean differences and risk ratios for continuous and dichotomous variables, respectively.

RESULTS

Eight studies were included, and the pooled analysis suggested that the T genotype of SNP rs11190870 leads to a higher risk of AIS in multiple ethnic groups regardless of gender (Total:OR, 1.66, 95% CI 1.53, 1.79; I² = 37.3%, P = 0.000, Female: OR, 1.62, 95% CI 1.50, 1.73; I² = 26.7%, P = 0.000, Male: OR, 1.79, 95% CI 1.38, 2.20; I2 = 0.00%, P = 0.000). Additionally, the TT and TC genotype had a larger Cobb angle than those with the CC genotype in the overall and female Asian populations.

CONCLUSION

A significant association of rs11190870 with AIS was observed in multiple ethnic groups regardless of gender. Additionally, a significant association was found between rs11190870 and curve severity in the overall and female Asian populations. Due to the limited data and clinical heterogeneity, further studies with large sample sizes are required.

Association of rs11190870 near LBX1 with adolescent idiopathic scoliosis susceptibility in a Han Chinese population

PURPOSE

To investigate whether rs11190870 near LBX1 correlates with the susceptibility or curve progression of adolescent idiopathic scoliosis (AIS) in a Han Chinese population.

METHODS

A total of 949 AIS patients and 976 age-matched healthy controls were recruited. All the subjects were genotyped using the PCR-based invader assay. Case-control study and case-only study were performed to define the contribution of rs11190870 to predisposition and curve severity of AIS. Additionally, we further conducted a meta-analysis of the study findings together with those of previously reported studies.

RESULTS

A significant association of rs11190870 with AIS was observed in the Han Chinese population (P = 1.8 × 10(-9); odd ratio = 1.51; 95 % confidence interval = 1.33-1.71), and AIS patients with TT genotype had a larger Cobb angle than those with TC or CC genotype (P = 0.005). The meta-analysis confirmed that the positive association of this SNP with AIS in the East Asian population.

CONCLUSIONS

The SNP rs11190870 near LBX1 is associated with both susceptibility and curve progression of AIS.

Transcription factor lbx1 expression in mouse embryonic stem cell-derived phenotypes

Transcription factor Lbx1 is known to play a role in the migration of muscle progenitor cells in limb buds and also in neuronal determination processes. In addition, involvement of Lbx1 in cardiac neural crest-related cardiogenesis was postulated. Here, we used mouse embryonic stem (ES) cells which have the capacity to develop into cells of all three primary germ layers. During in vitro differentiation, ES cells recapitulate cellular developmental processes and gene expression patterns of early embryogenesis. Transcript analysis revealed a significant upregulation of Lbx1 at the progenitor cell stage. Immunofluorescence staining confirmed the expression of Lbx1 in skeletal muscle cell progenitors and GABAergic neurons. To verify the presence of Lbx1 in cardiac cells, triple immunocytochemistry of ES cell-derived cardiomyocytes and a quantification assay were performed at different developmental stages. Colabeling of Lbx1 and cardiac specific markers troponin T, α-actinin, GATA4, and Nkx2.5 suggested a potential role in early myocardial development.