Shorter (GT)n repeats in the haem-oxygenase 1 gene promoter are associated with better mid-term survival in subjects with coronary artery disease and abnormal ejection fraction.

BACKGROUND: Haem oxygenase (HO)-1 is a rate-limiting enzyme for degrading haem into carbon monoxide. Subjects with longer GT repeats in the HO-1 gene (HMOX1) promoter are more likely to have coronary artery disease (CAD) and cardiovascular events. METHODS: We retrospectively enrolled CAD subjects with an abnormal ejection fraction (EF) <50% from our catheterisation data (N = 670). Polymerase chain reactions were performed for amplifying the HMOX1 promoter GT repeating segment to determine the number of repeats. RESULTS: In a median follow-up period of 40 months, 213 patients died. The distribution of genotype for HMOX1 promoter GT repeating segments SS, SL, and LL were significantly different (p < 0.001) between the dead (44.6%, 36.2%, 19.2%, respectively) and the survived (53.8%, 37.4%, 8.8%, respectively) (S allele: ≤30 repeats, L allele: >30 repeats). In Cox regression analysis, carrier of S allele (hazard ratio 0.665, p = 0.027), a higher EF (hazard ratio 0.037, p = 0.001), and revascularization with PCI were all negatively associated with all-cause death in subjects with CAD and abnormal EF. CONCLUSIONS: Carrier of shorter (GT)n repeats of HMOX1 gene promoter was negatively correlated with death events in CAD patients with abnormal EF.

Subjects with coronary artery disease and reduced ejection fraction have longer (GT)n repeats in the heme-oxygenase 1 gene promoter.

Heme oxygenase (HO)-1 is a rate-limiting enzyme for degrading heme into carbon monoxide. Longer (GT)n repeat of the HO-1 gene (HMOX1) promoter has a lower transcription rate. Subjects with longer GT repeats in the HMOX1 promoter are more likely to have coronary artery disease (CAD) and cardiovascular events. We retrospectively enrolled CAD subjects with an abnormal ejection fraction (EF) < 50% from our catheterization data (N = 670). Polymerase chain reactions were performed for amplifying the HMOX1 promoter GT repeating segment to determine the number of repeats. Two subgroups, reduced EF < 40% (N = 256), and mid-range EF 40-49% (N = 414), were compared. The distribution of genotypes of SS, SL and LL were significantly different in reduced EF (29%, 48%, 23%) vs. mid-range EF CAD (64%, 30%, 5%) (S allele: ≤ 30 repeats, L allele: > 30 repeats) (p < 0.001). The patients with reduced EF had a significantly longer average (GT)n (median 27.5 vs. 26.5, p = 0.004) than those with the mid-range EF. In multivariate analysis, the carrier of L allele (odds ratio 4.437, p < 0.001) was a significant predictor for the diagnosis of reduced vs. mid-range EF CAD. In conclusion, CAD patients with reduced EF had longer HMOX1 promoter (GT)n repeats than those with mid-range EF.

Subjects with microvascular angina have longer GT repeats polymorphism in the haem oxygenase-1 gene promoter.

Objective: Few studies have investigated haem oxygenase-1 gene (HMOX1) promoter polymorphism in microvascular angina (MVA).Materials and methods: HMOX1 promoter (GT)n repeats were examined in healthy controls (N = 220) and MVA subjects (N = 181).Results: The distribution of genotype of SS, SL and LL were significantly different in MVA (17%, 51%, 33%) vs. normal controls (35%, 46%, 20%) (p < 0.001, S allele: ≤30 repeats, L allele: >30 repeats). In multivariate analysis, carrier of L allele (odds ratio 2.772, p < 0.001) was a significant predictor for the diagnosis of MVA.Conclusions: Subjects with MVA had longer HMOX1 promoter (GT)n repeats than the healthy controls. Trial registration number: NCT01198730 at https://clinicaltrials.gov.

Prevalence and prognosis of genetically proven familial hypercholesterolemia in subjects with coronary artery disease and reduced ejection fraction.

Few studies have genetically screened variants related to familial hypercholesterolemia (FH) and investigated their survival impact in patients with coronary artery disease (CAD) and reduced left ventricular ejection fraction (EF). Patients with CAD and reduced EF (< 40%) were enrolled. Their genomic DNAs were sequenced for FH-related genes. All-cause and cardiovascular mortality data served as the major outcome. A total of 256 subjects were analyzed and 12 subjects (4.7%) carried FH-related genetic variants. After a median follow-up period of 44 months, 119 of the study subjects died. Cox survival analysis showed that carrying the FH genetic variant did not have a significant impact on the survival of CAD with reduced EF. However, higher estimated glomerular filtration rate (eGFR), better EF and beta blocker use were protective for a lower all-cause mortality. Further larger studies are needed to evaluate the impact of carrying the FH-related genetic variant on survival of CAD with reduced EF.

Roles of trans and cis variation in yeast intraspecies evolution of gene expression.

Both cis and trans mutations contribute to gene expression divergence within and between species. We used Saccharomyces cerevisiae as a model organism to estimate the relative contributions of cis and trans variations to the expression divergence between a laboratory (BY) and a wild (RM) strain of yeast. We examined whether genes regulated by a single transcription factor (TF; single input module, SIM genes) or genes regulated by multiple TFs (multiple input module, MIM genes) are more susceptible to trans variation. Because a SIM gene is regulated by a single immediate upstream TF, the chance for a change to occur in its trans-acting factors would, on average, be smaller than that for a MIM gene. We chose 232 genes that exhibited expression divergence between BY and RM to test this hypothesis. We examined the expression patterns of these genes in a BY-RM coculture system and in a BY-RM diploid hybrid. We found that trans variation is far more important than cis variation for expression divergence between the two strains. However, because in 75% of the genes studied, cis variation has significantly contributed to expression divergence, cis change also plays a significant role in intraspecific expression evolution. Interestingly, we found that the proportion of genes with diverged expression between BY and RM is larger for MIM genes than for SIM genes; in fact, the proportion tends to increase with the number of transcription factors that regulate the gene. Moreover, MIM genes are, on average, subject to stronger trans effects than SIM genes, though the difference between the two types of genes is not conspicuous.

Aryl Hydrocarbon Receptor Deficiency Attenuates Oxidative Stress-Related Mesangial Cell Activation and Macrophage Infiltration and Extracellular Matrix Accumulation in Diabetic Nephropathy.

AIMS: Activation of glomerular mesangial cells (MCs) and functional changes of renal tubular cells are due to metabolic abnormalities, oxidative stress, and matrix accumulation in the diabetic nephropathy (DN). Aryl hydrocarbon receptor (AhR) activation has been implicated in DN. In this study, we investigated the role of AhR in the pathophysiological processes of DN using AhR knockout (AhRKO) and pharmacological inhibitor α-naphthoflavone mouse models. RESULTS: The increased blood glucose, glucose intolerance, MC activation, macrophage infiltration, and extracellular matrix (ECM) accumulation were significantly attenuated in AhRKO mice with diabetic inducer streptozotocin (STZ) treatment. AhR deficiency by genetic knockout or pharmacological inhibition also decreased the induction of cyclooxygenase-2 (COX-2)/prostaglandin E2 (PGE2), lipid peroxidation, oxidative stress, NADPH oxidase activity, and N-ɛ-carboxymethyllysine (CML, a major advanced glycation end product) in STZ-induced diabetic mice. CML showed remarkably increased AhR/COX-2 DNA-binding activity, protein-DNA interactions, gene regulation, and ECM formation in MCs and renal proximal tubular cells, which could be reversed by siRNA-AhR transfection. CML-increased AhR nuclear translocation and biological activity in MCs and renal proximal tubular cells could also be effectively attenuated by antioxidants. INNOVATION: We elucidate for the first time that AhR plays an important role in MC activation, macrophage infiltration, and ECM accumulation in DN conferred by oxidative stress. CONCLUSIONS: AhR-regulated COX-2/PGE2 expression and ECM deposition through oxidative stress cascade is involved in the CML-triggered MC activation and macrophage infiltration. These findings suggest new insights into the development of therapeutic approaches to reduce diabetic microvascular complications. Antioxid. Redox Signal. 24, 217-231.

Expression evolution in yeast genes of single-input modules is mainly due to changes in trans-acting factors.

Both cis- and trans-regulatory mutations contribute to gene expression divergence within and between species. To estimate their relative contributions, we examined two yeast strains, BY (a laboratory strain) and RM (a wild strain), for their gene-expression divergence by microarray. Using these data and published ChIP-chip data, we obtained a set of single-regulator-regulated genes that showed expression divergence between BY and RM. We randomly selected 50 of these genes for further study. We developed a step-by-step approach to assess the relative contributions of cis- and trans-variations to expression divergence by using pyrosequencing to quantify the mRNA levels of the BY and RM alleles in the same culture (co-culture) and in hybrid diploids. Forty genes showed expression divergence between the two strains in co-culture, and pyrosequencing of the BY/RM hybrid diploids showed that 45% (18/40) can be attributed to differences in trans-acting factors alone, 17.5% (7/40) mainly to trans-variations, 20% (8/40) to both cis- and trans-acting factors, 7.5% (3/40) mainly to cis-variations, and 10% (4/40) to cis-acting factors alone. In addition, we replaced the BY promoter by the RM promoter in each of 10 BY genes that were found from our microarray data to have expression divergence between BY and RM, and in each case our quantitative PCR analysis revealed a cis effect of the promoter replacement on gene expression. In summary, our study suggests that trans-acting factors play the major role in expression evolution between yeast strains, but the role of cis variation is also important.

Gene transfer of glial cell line-derived neurotrophic factor promotes functional recovery following spinal cord contusion.

Neuronal cell death and the failure of axonal regeneration cause a permanent functional deficit following spinal cord injury (SCI). Administration of recombinant glial cell line-derived neurotrophic factor (GDNF) has previously been reported to rescue neurons following severe SCI, resulting in improved hindlimb locomotion in rats. In this study, thus, GDNF gene therapy using an adenoviral vector (rAd-GDNF) was examined in rats following SCI induced by dropping the NYU weight-drop impactor from a height of 25 mm onto spinal segment T9-T10. To evaluate the efficacy of intraspinal injection of recombinant adenovirus into the injured spinal cord, we observed green fluorescent protein (GFP) gene transfer in the contused spinal cord. GFP was effectively expressed in the injured spinal cord, and the most prominently transduced cells were astrocytes. The expression of GDNF was detected only in rats receiving rAd-GDNF, not the controls, and remained detectable around the injured site for at least 8 days. Open-field locomotion analysis revealed that rats receiving rAd-GDNF exhibited improved locomotor function and hindlimb weight support compared to the control groups. Immunohistochemical examination for the neuronal marker, calcitonin gene-related peptide (CGRP), showed an increase in CGRP+ neuronal fibers in the injured spinal cord in rats receiving rAd-GDNF treatment. Collectively, the results suggest that adenoviral gene transfer of GDNF can preserve neuronal fibers and promote hindlimb locomotor recovery from spinal cord contusion. This research should provide information for developing a clinical strategy for GDNF gene therapy.