Modulation of Cardiac Performance by Motor Protein Gene Transfer

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75444/1/annals.1420.011.pd

An exploration of heat tolerance in mice utilizing mRNA and microRNA expression analysis

Background Individuals who rapidly develop hyperthermia during heat exposure (heat-intolerant) are vulnerable to heat associated illness and injury. We recently reported that heat intolerant mice exhibit complex alterations in stress proteins in response to heat exposure. In the present study, we further explored the role of genes and molecular networks associated with heat tolerance in mice. Methodology Heat-induced physiological and biochemical changes were assessed to determine heat tolerance levels in mice. We performed RNA and microRNA expression profiling on mouse gastrocnemius muscle tissue samples to determine novel biological pathways associated with heat tolerance. Principal Findings Mice (n = 18) were assigned to heat-tolerant (TOL) and heat-intolerant (INT) groups based on peak core temperatures during heat exposures. This was followed by biochemical assessments (Hsp40, Hsp72, Hsp90 and Hsf1 protein levels). Microarray analysis identified a total of 3,081 mRNA transcripts that were significantly misregulated in INT compared to TOL mice (p\u3c0.05). Among them, Hspa1a, Dnajb1 and Hspb7 were differentially expressed by more than two-fold under these conditions. Furthermore, we identified 61 distinct microRNA (miRNA) sequences significantly associated with TOL compared to INT mice; eight miRNAs corresponded to target sites in seven genes identified as being associated with heat tolerance pathways (Hspa1a, Dnajb1, Dnajb4, Dnajb6, Hspa2, Hspb3 and Hspb7). Conclusions The combination of mRNA and miRNA data from the skeletal muscle of adult mice following heat stress provides new insights into the pathophysiology of thermoregulatory disturbances of heat intolerance

Individual differences in emotion-cognition interactions: Emotional valence interacts with serotonin transporter genotype to influence brain systems involved in emotional reactivity and cognitive control

The serotonin transporter gene (5-HTTLPR) influences emotional reactivity and attentional bias toward or away from emotional stimuli, and has been implicated in psychopathological states, such as depression and anxiety disorder. The short allele is associated with increased reactivity and attention toward negatively-valenced emotional information, whereas the long allele is associated with increased reactivity and attention towardpositively-valenced emotional information. The neural basis for individual differences in the ability to exert cognitive control over these bottom-up biases in emotional reactivity and attention is unknown, an issue investigated in the present study. Healthy adult participants were divided into two groups, either homozygous carriers of the 5-HTTLPR long allele or homozygous carriers of the short allele, and underwent functional magnetic resonance imaging (fMRI) while completing an Emotional Stroop-like task that varied in the congruency of task-relevant and task-irrelevant information and the emotional valence of the task-irrelevant information. Behaviorally, participants demonstrated the classic “Stroop effect” (responses were slower for incongruent than congruent trials), which did not differ by 5-HTTLPR genotype. However, fMRI results revealed that genotype influenced the degree to which neural systems were engaged depending on the valence of the conflicting task-irrelevant information. While the “Long” group recruited prefrontal control regions and superior temporal sulcus during conflict when the task-irrelevant information was positively-valenced, the “Short” group recruited these regions during conflict when the task-irrelevant information was negatively-valenced. Thus, participants successfully engaged cognitive control to overcome conflict in an emotional context using similar neural circuitry, but the engagement of this circuitry depended on emotional valence and 5-HTTLPR status. These results suggest that the interplay between emotion and cognition is modulated, in part, by a genetic polymorphism that influences serotonin neurotransmission

Temporal patterns of gene expression after acute hindlimb ischemia in mice insights into the genomic program for collateral vessel development

AbstractObjectivesWe sought to understand the genomic program leading to collateral vessel formation.BackgroundRecently, technology has advanced to the point that it is now possible to elucidate the large array of genes that must be expressed, as well as the temporal expression pattern, for the development of functionally important collateral vessels. In this investigation, we used deoxyribonucleic acid array expression profiling to determine the time course of differential expression of 12,000 genes after femoral artery ligation in C57BL/6 mice.MethodsRibonucleic acid was extracted from the adductor muscle, which showed no signs of ischemia. Sampling was at baseline, 6 h, and 1, 3, 7, and 14 days after femoral artery ligation or sham operation.ResultsFemoral artery ligation caused the differential expression (>2-fold) of 783 genes at one or multiple time points: 518 were induced and 265 were repressed. Cluster analysis generated four temporal patterns: 1) early upregulated (6 to 24 h)—immediate early transcriptional factors, angiogenesis, inflammation, and stress-related genes; 2) mid-phase upregulated (day 3)—cell cycle and cytoskeletal and inflammatory genes; 3) late upregulated (days 7 to 14)—angiostatic, anti-inflammatory, and extracellular matrix-associated genes; and 4) downregulated—genes involved in energy metabolism, water channel, and muscle contraction. Microarray data were validated using quantitative reverse transcription polymerase chain reaction.ConclusionsThis study documents the large number of genes whose differential expression and temporal functional clustering appear to contribute to collateral formation. These results can serve as a genomic model for arteriogenesis and as a database for developing new therapeutic strategies

Characterization of the ZBTB42 gene in humans and mice

A 12 kb haplotype upstream of the key signaling protein gene, AKT1, has been associated with insulin resistance and metabolic syndrome (Devaney et al. 2010). The region contains the first exon and promoter sequences of AKT1, but also includes the complete transcript unit for a highly conserved yet uncharacterized zinc finger-containing protein (ZBTB42). One of the component SNPs of the 12 kb haplotype metabolic syndrome haplotype changes a conserved amino acid in the predicted ZBTB42 protein, increasing the potential significance of the ZBTB42 transcript unit for contributing to disease risk. Using RT-PCR of human and mouse cells, we verified that the two exon ZBTB42 was expressed and correctly spliced in human skeletal muscle, and murine C2C12 cells. Production of peptide antibodies showed the expected protein in human (47 kD) and mouse (49 kD) immunoblots, and murine tissue distribution showed strongest expression in muscle and ovary. Immunostaining showed nuclear localization of the ZBTB42 protein in human muscle. Confocal imaging analyses of murine muscle showed ZBTB42 distributed in the nucleoplasm, with particular enrichment in nuclei underlying the neuromuscular junctions. The genetic association data of metabolic syndrome, coupled with the molecular characterization of the ZBTB42 transcript unit and encoded protein presented here, suggests that ZBTB42 may be involved in metabolic syndrome phenotypes

Genomics in premature infants: A non-invasive strategy to obtain high-quality DNA

We used a cost-effective, non-invasive method to obtain high-quality DNA from buccal epithelial-cells (BEC) of premature infants for genomic analysis. DNAs from BEC were obtained from premature infants with gestational age ≤ 36 weeks. Short terminal repeats (STRs) were performed simultaneously on DNA obtained from the buccal swabs and blood from the same patient. The STR profiles demonstrated that the samples originated from the same individual and exclude any contamination by external DNAs. Whole exome sequencing was performed on DNAs obtained from BEC on premature infants with and without necrotizing enterocolitis, and successfully provided a total number of reads and variants corroborating with those obtained from healthy blood donors. We provide a proof of concept that BEC is a reliable and preferable source of DNA for high-throughput sequencing in premature infants

Are Immune Modulating Single Nucleotide Polymorphisms Associated with Necrotizing Enterocolitis?

Necrotizing enterocolitis (NEC) is a devastating gastrointestinal emergency. The purpose of this study is to determine if functional single nucleotide polymorphisms (SNPs) in immune-modulating genes pre-dispose infants to NEC. After Institutional Review Board approval and parental consent, buccal swabs were collected for DNA extraction. TaqMan allelic discrimination assays and BglII endonuclease digestion were used to genotype specific inflammatory cytokines and TRIM21. Statistical analysis was completed using logistic regression. 184 neonates were analyzed in the study. Caucasian neonates with IL-6 (rs1800795) were over 6 times more likely to have NEC (p = 0.013; OR = 6.61, 95% CI 1.48-29.39), and over 7 times more likely to have Stage III disease (p = 0.011; OR = 7.13, (95% CI 1.56-32.52). Neonates with TGFβ-1 (rs2241712) had a decreased incidence of NEC-related perforation (p = 0.044; OR = 0.28, 95% CI: 0.08-0.97) and an increased incidence of mortality (p = 0.049; OR = 2.99, 95% CI: 1.01 - 8.86). TRIM21 (rs660) was associated with NEC-related intestinal perforation (p = 0.038; OR = 4.65, 95% CI 1.09-19.78). In premature Caucasian neonates, the functional SNP IL-6 (rs1800795) is associated with both the development and increased severity of NEC. TRIM21 (rs660) and TGFβ-1 (rs2241712) were associated with NEC- related perforation in all neonates in the cohort. These findings suggest a possible genetic role in the development of NEC

UK Housing Market: Time Series Processes with Independent and Identically Distributed Residuals

The paper examines whether a univariate data generating process can be identified which explains the data by having residuals that are independent and identically distributed, as verified by the BDS test. The stationary first differenced natural log quarterly house price index is regressed, initially with a constant variance and then with a conditional variance. The only regression function that produces independent and identically distributed standardised residuals is a mean process based on a pure random walk format with Exponential GARCH in mean for the conditional variance. There is an indication of an asymmetric volatility feedback effect but higher frequency data is required to confirm this. There could be scope for forecasting the index but this is tempered by the reduction in the power of the BDS test if there is a non-linear conditional variance process

Common variants at 10 Genomic loci influence hemoglobin A1C levels via glycemic and nonglycemic pathways

OBJECTIVE: Glycated hemoglobin (HbA(1c)), used to monitor and diagnose diabetes, is influenced by average glycemia over a 2- to 3-month period. Genetic factors affecting expression, turnover, and abnormal glycation of hemoglobin could also be associated with increased levels of HbA(1c). We aimed to identify such genetic factors and investigate the extent to which they influence diabetes classification based on HbA(1c) levels. RESEARCH DESIGN AND METHODS: We studied associations with HbA(1c) in up to 46,368 nondiabetic adults of European descent from 23 genome-wide association studies (GWAS) and 8 cohorts with de novo genotyped single nucleotide polymorphisms (SNPs). We combined studies using inverse-variance meta-analysis and tested mediation by glycemia using conditional analyses. We estimated the global effect of HbA(1c) loci using a multilocus risk score, and used net reclassification to estimate genetic effects on diabetes screening. RESULTS: Ten loci reached genome-wide significant association with HbA(1c), including six new loci near FN3K (lead SNP/P value, rs1046896/P = 1.6 × 10(−26)), HFE (rs1800562/P = 2.6 × 10(−20)), TMPRSS6 (rs855791/P = 2.7 × 10(−14)), ANK1 (rs4737009/P = 6.1 × 10(−12)), SPTA1 (rs2779116/P = 2.8 × 10(−9)) and ATP11A/TUBGCP3 (rs7998202/P = 5.2 × 10(−9)), and four known HbA(1c) loci: HK1 (rs16926246/P = 3.1 × 10(−54)), MTNR1B (rs1387153/P = 4.0 × 10(−11)), GCK (rs1799884/P = 1.5 × 10(−20)) and G6PC2/ABCB11 (rs552976/P = 8.2 × 10(−18)). We show that associations with HbA(1c) are partly a function of hyperglycemia associated with 3 of the 10 loci (GCK, G6PC2 and MTNR1B). The seven nonglycemic loci accounted for a 0.19 (% HbA(1c)) difference between the extreme 10% tails of the risk score, and would reclassify ∼2% of a general white population screened for diabetes with HbA(1c). CONCLUSIONS: GWAS identified 10 genetic loci reproducibly associated with HbA(1c). Six are novel and seven map to loci where rarer variants cause hereditary anemias and iron storage disorders. Common variants at these loci likely influence HbA(1c) levels via erythrocyte biology, and confer a small but detectable reclassification of diabetes diagnosis by HbA(1c)

PPAR alpha L162V underlies variation in serum triglycerides and subcutaneous fat volume in young males

Background: Of the five sub-phenotypes defining metabolic syndrome, all are known to have strong genetic components ( typically 50 - 80% of population variation). Studies defining genetic predispositions have typically focused on older populations with metabolic syndrome and/or type 2 diabetes. We hypothesized that the study of younger populations would mitigate many confounding variables, and allow us to better define genetic predisposition loci for metabolic syndrome. Methods: We studied 610 young adult volunteers ( average age 24 yrs) for metabolic syndrome markers, and volumetric MRI of upper arm muscle, bone, and fat pre- and post-unilateral resistance training. Results: We found the PPARa L162V polymorphism to be a strong determinant of serum triglyceride levels in young White males, where carriers of the V allele showed 78% increase in triglycerides relative to L homozygotes ( LL = 116 +/- 11 mg/ dL, LV = 208 +/- 30 mg/ dL; p = 0.004). Men with the V allele showed lower HDL ( LL = 42 +/- 1 mg/ dL, LV = 34 +/- 2 mg/ dL; p = 0.001), but women did not. Subcutaneous fat volume was higher in males carrying the V allele, however, exercise training increased fat volume of the untrained arm in V carriers, while LL genotypes significantly decreased in fat volume ( LL = - 1,707 +/- 21 mm(3), LV = 17,617 +/- 58 mm(3); p = 0.002), indicating a systemic effect of the V allele on adiposity after unilateral training. Our study suggests that the primary effect of PPARa L162V is on serum triglycerides, with downstream effects on adiposity and response to training. Conclusion: Our results on association of PPARa and triglycerides in males showed a much larger effect of the V allele than previously reported in older and less healthy populations. Specifically, we showed the V allele to increase triglycerides by 78% ( p = 0.004), and this single polymorphism accounted for 3.8% of all variation in serum triglycerides in males ( p = 0.0037)