Caroline Ojaimi - Academia.edu (original) (raw)

Papers by Caroline Ojaimi

Research paper thumbnail of Altered expression of a limited number of genes contributes to cardiac decompensation during chronic ventricular tachypacing in dogs

Physiological Genomics, 2006

Our aim was to determine the changes in the gene expression profile occurring during the transiti... more Our aim was to determine the changes in the gene expression profile occurring during the transition from compensated dysfunction (CD) to decompensated heart failure (HF) in pacinginduced dilated cardiomyopathy. Twelve chronically instrumented dogs underwent left ventricular pacing at 210 beats/min for 3 weeks and at 240 beats thereafter and 4 normal dogs were used as control. The transition from CD to HF occurred between the 3 rd to 4 th week of pacing, with end-stage HF at 28±1 days. RNA was extracted from left ventricular tissue at control, 3 and 4 weeks of pacing (n=4) and tested with the Affymetrix Canine Array. 509 genes were differentially expressed in CD versus control (PE0.05; fold change F ±2), with 362 increasing and 147 decreasing. 526 genes were differentially expressed in HF versus control (PE0.05; fold change F ±2), with 439 increasing and 87 decreasing. To better understand the transition, we compared gene alterations at 3 versus 4 weeks pacing and found that only 30 genes differed (P 0.05; fold change of ±2). We conclude that a number of processes including normalization of gene regulation during decompensation, appearance of new up-regulated genes and maintenance of gene expression all contribute to the transition to overt heart failure with an unexpectedly small number of genes differentially regulated.

Research paper thumbnail of Differential cardiac gene expression in atorvastatin-treated dogs

The Faseb Journal, Apr 1, 2007

Research paper thumbnail of Recurrent TERT Promoter Mutations in Urothelial Carcinoma and Potential Clinical Applications

Annals of Diagnostic Pathology, 2015

Research paper thumbnail of COX-2 contributes to the maintenance of flow-induced dilation in arterioles of eNOS-knockout mice

AJP Heart and Circulatory Physiology

Our previous studies demonstrated that, in gracilis muscle arterioles of male mice deficient in t... more Our previous studies demonstrated that, in gracilis muscle arterioles of male mice deficient in the gene for endothelial nitric oxide synthase (eNOS), flow-induced dilation (FID) is mediated by endothelial PGs. Thus the present study aimed to identify the specific isoform of cyclooxygenase (COX) responsible for the compensatory mediation of FID in arterioles of eNOS-knockout (KO) mice. Experiments were conducted on gracilis muscle arterioles of male eNOS-KO and wild-type (WT) mice. Basal tone and magnitude of FID of arterioles were comparable in the two strains of mice. A role for COX isoforms in the mediation of the responses was assessed by use of valeryl salicylate (3 mM) and NS-398 (10 microM), inhibitors of COX-1 and COX-2, respectively. In eNOS-KO arterioles, valeryl salicylate or NS-398 alone inhibited FID (at maximal flow rate) by approximately 51% and approximately 58%, respectively. Administration of both inhibitors eliminated the dilation. In WT arterioles, inhibition of COX-2 did not significantly affect FID, whereas inhibition of COX-1 decreased the dilation by approximately 57%. The residual portion of the response was abolished by additional administration of Nomega-nitro-L-arginine methyl ester. Western blot analysis indicated a comparable content of COX-1 protein in arterioles of WT and eNOS-KO mice. COX-2 protein, which was not detectable in arterioles of WT mice, was strongly expressed in arterioles of eNOS-KO mice, together with an upregulation of COX-2 gene expression. Immunohistochemical staining confirmed the presence of COX-2 in the endothelium of eNOS-KO arterioles. In conclusion, COX-2-derived PGs are the mediators responsible for maintenance of FID in arterioles of eNOS-deficient mice.

Research paper thumbnail of Borrelia burgdorferi gene expression profiling with membrane-based arrays

Methods in Enzymology, 2002

... ELIAS, ALAN BARBOUR, ALGIS JASINSKAS, JORGE BENACH, LAURA KATONAH, JUSTIN RADOLF, MELISSA CAI... more ... ELIAS, ALAN BARBOUR, ALGIS JASINSKAS, JORGE BENACH, LAURA KATONAH, JUSTIN RADOLF, MELISSA CAIMANO, JON SKARE, KRISTEN ... variation in plasmid content among isolates and some of these extrachromosomal elements are lost on serial propagation. ...

Research paper thumbnail of Conservation of gene arrangement and an unusual organization of rRNA genes in the linear chromosomes of the Lyme disease spirochaetes Borrelia burgdorferi, B. garinii and B. afzelii

Microbiology, 1994

Physical maps of the chromosomes of the Lyme disease spirochaetes Borrelia garinii and Borrelia a... more Physical maps of the chromosomes of the Lyme disease spirochaetes Borrelia garinii and Borrelia afielii have been elucidated for the enzymes Cspl, SgrAl, I-Ceul, Smal, Eagl, BssHII, MluI and Apal by two-dimensional pulsed-field gel electrophoresis techniques. The maps contain 42 sites for B. garinii and 32 for B. afielii. The mapping studies showed that the two chromosomes are linear DNA molecules of 953 and 948 kbp, respectively. A comparison of the physical maps of B. garinii and B. afielii and the published map of the other Lyme disease spirochaete, Borrelia burgdorferi [Davidson, B. E. , MacDougall, J. & Saint Girons, 1. (1992) J Bacteriol 174,3766-37741 revealed that the three chromosomes have f e w endonuclease sites in common, apart from a cluster in rrl (encoding 23s rRNA) and rrs (encoding 165 rRNA).

Research paper thumbnail of Premature death and age-related cardiac dysfunction in male eNOS-knockout mice

Journal of Molecular and Cellular Cardiology, 2004

The aims of our study were to determine mortality, and age-and genotype-related cardiac phenotype... more The aims of our study were to determine mortality, and age-and genotype-related cardiac phenotype in endothelial nitric oxide synthase (NOS) knockout (-/-) and wild-type (+/+) mice. Male and female (-/-) and male and female (+/+) conscious mice were studied at different ages by echocardiography and tail-cuff blood pressure (BP) measurement. Only 50% male (-/-) mice lived longer than 21 months whereas 89% (+/+) mice were still alive after 24 months (P < 0.005). There was little mortality in female mice of either genotype. Both (-/-) and (+/+) male mice have normal cardiac dimensions and function at 5.5 months. However, (-/-) mice developed cardiac dilation and dysfunction at 21 months as evidenced by a significant increase (P < 0.05) in left ventricular (LV) end-diastolic diameter from 2.69 ± 0.13 to 3.13 ± 0.09 mm, LV end-systolic diameter from 1.28 ± 0.11 to 1.86 ± 0.12 mm, LV end-diastolic cavity volume from 21 ± 2.8 to 31 ± 2.5 µl and LV mass from 19 ± 2.5 to 27 ± 1.9 mg/10 g and a significant decrease (P < 0.05) in ejection fraction (from 65 ± 3.3% to 41 ± 4.6%), shortening fraction (from 53 ± 2.2% to 41 ± 3.4%), LV posterior wall thickening (from 27 ± 2% to 12 ± 4%) and septum thickening (from 27 ± 2% to 12 ± 4%) compared with those at 5.5 months. There was a clear increase in cardiac weight and cardiac dilation by hematoxylin and eosin in male (-/-) mice at 21 months. BP in male (-/-) mice fell with the cardiac dysfunction, whereas female (-/-) mice were hypertensive even at 21 months. The level of mRNA for neuronal NOS and inducible NOS was greater in all females compared to males. These results indicate that male (-/-) mice have a significantly shorter lifespan than (+/+) or female mice, and male (-/-) mice develop cardiac dysfunction with age.

Research paper thumbnail of Comparative Transcriptional Profiling of Borrelia burgdorferi Clinical Isolates Differing in Capacities for Hematogenous Dissemination

Infection and Immunity, 2005

Borrelia burgdorferi, the etiologic agent of Lyme disease, is genetically heterogeneous. Previous... more Borrelia burgdorferi, the etiologic agent of Lyme disease, is genetically heterogeneous. Previous studies have shown a significant association between the frequency of hematogenous dissemination in Lyme disease patients and the genotype of the infecting B. burgdorferi strain. Comparative transcriptional profiling of two representative clinical isolates with distinct genotypes (BL206 and B356) was undertaken. A total of 78 open reading frames (ORFs) had expression levels that differed significantly between the two isolates. A number of genes with potential involvement in nutrient uptake (BB0603, BBA74, BB0329, BB0330, and BBB29) have significantly higher expression levels in isolate B356. Moreover, nearly 25% of the differentially expressed genes are predicted to be localized on the cell surface, implying that these two isolates have cell surface properties that differ considerably. One of these genes, BBA74, encodes a protein of 257 amino acid residues that has been shown to possess porin activity. BBA74 transcript level was >20-fold higher in B356 than in BL206, and strain B356 contained three-to fivefold more BBA74 protein. BBA74 was disrupted by the insertion of a kanamycin resistance cassette into the coding region. The growth rates of both wild-type and mutant strains were essentially identical, and cultures reached the same final cell densities. However, the mutant strains consistently showed prolonged lags of 2 to 5 days prior to the induction of log-phase growth compared to wild-type strains. It is tempting to speculate that the absence of BBA74 interferes with the enhanced nutrient uptake that may be required for the entry of cells into log-phase growth. These studies demonstrate the value of comparative transcriptional profiling for identifying differences in the transcriptomes of B. burgdorferi clinical isolates that may provide clues to pathogenesis. The 78 ORFs identified here are a good starting point for the investigation of factors involved in the hematogenous dissemination of B. burgdorferi.

Research paper thumbnail of Profiling of Temperature-Induced Changes in Borrelia burgdorferi Gene Expression by Using Whole Genome Arrays

Infection and Immunity, 2003

Borrelia burgdorferi is the etiologic agent of Lyme disease, the most prevalent arthropod-borne d... more Borrelia burgdorferi is the etiologic agent of Lyme disease, the most prevalent arthropod-borne disease in the United States. The genome of the type strain, B31, consists of a 910,725-bp linear chromosome and 21 linear and circular plasmids comprising 610,694 bp. During its life cycle, the spirochete exists in distinctly different environments, cycling between a tick vector and a mammalian host. Temperature is one environmental factor known to affect B. burgdorferi gene expression. To identify temperature-responsive genes, genome arrays containing 1,662 putative B. burgdorferi open reading frames (ORFs) were prepared on nylon membranes and employed to assess gene expression in B. burgdorferi B31 grown at 23 and 35°C. Differences in expression of more than 3.5 orders of magnitude could be readily discerned and quantitated. At least minimal expression from 91% of the arrayed ORFs could be detected. A total of 215 ORFs were differentially expressed at the two temperatures; 133 were expressed at significantly greater levels at 35°C, and 82 were more significantly expressed at 23°C. Of these 215 ORFs, 134 are characterized as genes of unknown function. One hundred thirty-six (63%) of the differentially expressed genes are plasmid encoded. Of particular interest is plasmid lp54 which contains 76 annotated putative genes; 31 of these exhibit temperature-regulated expression. These findings underscore the important role plasmid-encoded genes may play in adjustment of B. burgdorferi to growth under diverse environmental conditions.

Research paper thumbnail of Abstract 704: Cardiac Progenitor Cell Aging Is Responsible for Organ Aging

Circulation, Oct 31, 2007

Research paper thumbnail of Long-term methionine-diet induced mild hyperhomocysteinemia associated cardiac metabolic dysfunction in multiparous rats

Physiological Reports, 2015

Mild hyperhomocysteinemia (HHcy, clinically defined as less than 30 lmol/L) is an independent car... more Mild hyperhomocysteinemia (HHcy, clinically defined as less than 30 lmol/L) is an independent cardiovascular disease (CVD) risk factor, and is associated with many complications during pregnancy, such as preeclampsia (PE). The aim of this study was to assess the effect of long-term mild HHcy on cardiac metabolic function of multiparous rats. Female rats were mated 3 to 4 times and were fed with methionine in drinking water to increase plasma Hcy (2.9 AE 0.3 to 10.5 AE 2.3 lmol/L) until termination. This caused significant increase of heart weight/body weight (0.24 AE 0.01 to 0.27 AE 0.01 g/100 g) and left ventricle weight (0.69 AE 0.03 to 0.78 AE 0.01 g). Superoxide production was increased by 2.5-fold in HHcy hearts using lucigenin chemiluminescence. The ability of bradykinin and carbachol to regulate myocardial oxygen consumption (MVO 2 ) in vitro was impaired by 59% and 66% in HHcy heart, and it was restored by ascorbic acid (AA), tempol, or apocynin (Apo). Protein expression of p22 phox subunit of NAD(P)H oxidase was increased by 2.6-fold, but there were no changes in other NAD(P)H oxidase subunits, NOSs or SODs. Microarray revealed 1518 genes to be differentially regulated (P < 0.05). The mRNA level of NAD(P)H oxidase subunits, NOSs or SODs remained unchanged. In conclusion, long-term mild HHcy increases cardiac superoxide mainly through regulation of p22 phox component of the NAD(P)H oxidase and impairs the ability of NO to regulate MVO 2 in heart of multiparous mothers.

Research paper thumbnail of Identification of a novel clone, ST736, among Enterococcus faecium clinical isolates and its association with daptomycin nonsusceptibility

Antimicrobial agents and chemotherapy, 2014

Resistance to daptomycin in enterococcal clinical isolates remains rare but is being increasingly... more Resistance to daptomycin in enterococcal clinical isolates remains rare but is being increasingly reported in the United States and worldwide. There are limited data on the genetic relatedness and microbiological and clinical characteristics of daptomycin-nonsusceptible enterococcal clinical isolates. In this study, we assessed the population genetics of daptomycin-nonsusceptible Enterococcus faecium (DNSE) clinical isolates by multilocus sequence typing (MLST) and whole-genome sequencing analysis. Forty-two nonduplicate DNSE isolates and 43 randomly selected daptomycin-susceptible E. faecium isolates were included in the analysis. All E. faecium isolates were recovered from patients at a tertiary care medical center in suburban New York City from May 2009 through December 2013. The daptomycin MICs of the DNSE isolates ranged from 6 to >256 μg/ml. Three major clones of E. faecium (ST18, ST412, and ST736) were identified among these clinical isolates by MLST and whole-genome seque...

Research paper thumbnail of Oxidant-NO dependent gene regulation in dogs with type I diabetes: impact on cardiac function and metabolism

Cardiovascular diabetology, 2010

The mechanisms responsible for the cardiovascular mortality in type I diabetes (DM) have not been... more The mechanisms responsible for the cardiovascular mortality in type I diabetes (DM) have not been defined completely. We have shown in conscious dogs with DM that: 1) baseline coronary blood flow (CBF) was significantly decreased, 2) endothelium-dependent (ACh) coronary vasodilation was impaired, and 3) reflex cholinergic NO-dependent coronary vasodilation was selectively depressed. The most likely mechanism responsible for the depressed reflex cholinergic NO-dependent coronary vasodilation was the decreased bioactivity of NO from the vascular endothelium. The goal of this study was to investigate changes in cardiac gene expression in a canine model of alloxan-induced type 1 diabetes. Mongrel dogs were chronically instrumented and the dogs were divided into two groups: one normal and the other diabetic. In the diabetic group, the dogs were injected with alloxan monohydrate (40-60 mg/kg iv) over 1 min. The global changes in cardiac gene expression in dogs with alloxan-induced diabete...

Research paper thumbnail of Genome Sequence of Borrelia chilensis VA1, a South American Member of the Lyme Borreliosis Group

Genome Announcements, 2015

Borrelia chilensis strain VA1 is a recently described South American member of the Borrelia burgd... more Borrelia chilensis strain VA1 is a recently described South American member of the Borrelia burgdorferi sensu lato complex from Chile. Whole-genome sequencing analysis determined its linear chromosome and plasmids lp54 and cp26, confirmed its membership in the Lyme borreliosis group, and will open new research avenues regarding its pathogenic potential.

Research paper thumbnail of Identification of a coronary vascular progenitor cell in the human heart

Proceedings of the National Academy of Sciences, 2009

Primitive cells capable of generating small resistance arterioles and capillary structures in the... more Primitive cells capable of generating small resistance arterioles and capillary structures in the injured myocardium have been identified repeatedly. However, these cells do not form large conductive coronary arteries that would have important implications in the management of the ischemic heart. In the current study, we determined whether the human heart possesses a class of progenitor cells that regulates the growth of endothelial cells (ECs) and smooth muscle cells (SMCs) and vasculogenesis. The expression of vascular endothelial growth-factor receptor 2 (KDR) was used, together with the stem cell antigen c-kit, to isolate and expand a resident coronary vascular progenitor cell (VPC) from human myocardial samples. Structurally, vascular niches composed of c-kit-KDR-positive VPCs were identified within the walls of coronary vessels. The VPCs were connected by gap junctions to ECs, SMCs, and fibroblasts that operate as supporting cells. In vitro, VPCs were self-renewing and clonogenic and differentiated predominantly into ECs and SMCs and partly into cardiomyocytes. To establish the functional import of VPCs, a critical stenosis was created in immunosuppressed dogs, and tagged human VPCs were injected in proximity to the constricted artery. One month later, there was an increase in coronary blood flow (CBF) distal to the stenotic artery, resulting in functional improvement of the ischemic myocardium. Regenerated large, intermediate, and small human coronary arteries and capillaries were found. In conclusion, the human heart contains a pool of VPCs that can be implemented clinically to form functionally competent coronary vessels and improve CBF in patients with ischemic cardiomyopathy.

Research paper thumbnail of Notch1 regulates the fate of cardiac progenitor cells

Proceedings of the National Academy of Sciences, 2008

This article contains supporting information online at www.pnas.org/cgi/content/full/ 0808357105/... more This article contains supporting information online at www.pnas.org/cgi/content/full/ 0808357105/DCSupplemental.

Research paper thumbnail of Altered expression of a limited number of genes contributes to cardiac decompensation during chronic ventricular tachypacing in dogs

Physiological genomics, Jan 14, 2007

Our aim was to determine the changes in the gene expression profile occurring during the transiti... more Our aim was to determine the changes in the gene expression profile occurring during the transition from compensated dysfunction (CD) to decompensated heart failure (HF) in pacing-induced dilated cardiomyopathy. Twelve chronically instrumented dogs underwent left ventricular pacing at 210 beats/min for 3 wk and at 240 beats thereafter, and four normal dogs were used as control. The transition from CD to HF occurred between the 3rd and 4th wk of pacing, with end-stage HF at 28 +/- 1 days. RNA was extracted from left ventricular tissue at control and 3 and 4 wk of pacing (n = 4) and tested with the Affymetrix Canine Array. We found 509 genes differentially expressed in CD vs. control (P < or = 0.05, fold change > or = +/-2), with 362 increasing and 147 decreasing; 526 genes were differentially expressed in HF vs. control (P < or = 0.05; fold change > or = +/-2), with 439 increasing and 87 decreasing. To better understand the transition, we compared gene alterations at 3 vs...

Research paper thumbnail of CYP2C29 Produces Superoxide in Response to Shear Stress

Microcirculation, 2012

Activation of CYP2C29 releases superoxide during shear stress-induced dilation (SSID). Mesenteric... more Activation of CYP2C29 releases superoxide during shear stress-induced dilation (SSID). Mesenteric arteries isolated from female eNOS-KO and WT mice were cannulated and pressurized. Vasodilation and superoxide production in response to shear stress were assessed. Shear stress-induced dilation was significantly attenuated in vessels of eNOS-KO compared with WT mice, which was normalized by tempol and PEG-Catalase, in a PPOH (inhibitor of CYP2C29)-sensitive manner, but remained unaffected by VAS2870 and allopurinol, inhibitors of NADPH oxidase and xanthine oxidase, respectively. NaNO(2)-induced dilation was comparable in both strains of mice. Confocal microscopy shows that SS-stimulated superoxide was increased particularly in the endothelium of eNOS-KO mice. HPLC analysis of 2-EOH indicated an increase in SS-stimulated superoxide in vessels of eNOS-KO mice, a response that was sensitive to PPOH. Inhibition of soluble epoxide hydrolase significantly enhanced SSID without affecting SS-stimulated superoxide production. CYP2C29 and catalase were upregulated, and exogenous H(2)O(2) caused vasoconstriction in vessels of eNOS-KO mice. CYP2C29 synthesizes EETs to mediate SSID, and simultaneously releases superoxide and sequential H(2)O(2), which in turn impair SSID.

Research paper thumbnail of Premature death and age-related cardiac dysfunction in male eNOS-knockout mice

Journal of Molecular and Cellular Cardiology, 2004

The aims of our study were to determine mortality, and age-and genotype-related cardiac phenotype... more The aims of our study were to determine mortality, and age-and genotype-related cardiac phenotype in endothelial nitric oxide synthase (NOS) knockout (-/-) and wild-type (+/+) mice. Male and female (-/-) and male and female (+/+) conscious mice were studied at different ages by echocardiography and tail-cuff blood pressure (BP) measurement. Only 50% male (-/-) mice lived longer than 21 months whereas 89% (+/+) mice were still alive after 24 months (P < 0.005). There was little mortality in female mice of either genotype. Both (-/-) and (+/+) male mice have normal cardiac dimensions and function at 5.5 months. However, (-/-) mice developed cardiac dilation and dysfunction at 21 months as evidenced by a significant increase (P < 0.05) in left ventricular (LV) end-diastolic diameter from 2.69 ± 0.13 to 3.13 ± 0.09 mm, LV end-systolic diameter from 1.28 ± 0.11 to 1.86 ± 0.12 mm, LV end-diastolic cavity volume from 21 ± 2.8 to 31 ± 2.5 µl and LV mass from 19 ± 2.5 to 27 ± 1.9 mg/10 g and a significant decrease (P < 0.05) in ejection fraction (from 65 ± 3.3% to 41 ± 4.6%), shortening fraction (from 53 ± 2.2% to 41 ± 3.4%), LV posterior wall thickening (from 27 ± 2% to 12 ± 4%) and septum thickening (from 27 ± 2% to 12 ± 4%) compared with those at 5.5 months. There was a clear increase in cardiac weight and cardiac dilation by hematoxylin and eosin in male (-/-) mice at 21 months. BP in male (-/-) mice fell with the cardiac dysfunction, whereas female (-/-) mice were hypertensive even at 21 months. The level of mRNA for neuronal NOS and inducible NOS was greater in all females compared to males. These results indicate that male (-/-) mice have a significantly shorter lifespan than (+/+) or female mice, and male (-/-) mice develop cardiac dysfunction with age.

Research paper thumbnail of Glucose-6-phosphate dehydrogenase-derived NADPH fuels superoxide production in the failing heart

Journal of Molecular and Cellular Cardiology, 2006

In the failing heart, NADPH oxidase and uncoupled NO synthase utilize cytosolic NADPH to form sup... more In the failing heart, NADPH oxidase and uncoupled NO synthase utilize cytosolic NADPH to form superoxide. NADPH is supplied principally by the pentose phosphate pathway, whose rate-limiting enzyme is glucose 6-phosphate dehydrogenase (G6PD). Therefore, we hypothesized that cardiac G6PD activation drives part of the excessive superoxide production implicated in the pathogenesis of heart failure. Pacing-induced heart failure was performed in eight chronically instrumented dogs. Seven normal dogs served as control. End-stage failure occurred after 28 ± 1 days of pacing, when left ventricular end-diastolic pressure reached 25 mm Hg. In left ventricular tissue homogenates, spontaneous superoxide generation measured by lucigenin (5 μM) chemiluminescence was markedly increased in heart failure (1338 ± 419 vs. 419 ± 102 AU/mg protein, P < 0.05), as were NADPH levels (15.4 ± 1.5 vs. 7.5 ± 1.5 μmol/gww, P < 0.05). Superoxide production was further stimulated by the addition of NADPH. The NADPH oxidase inhibitor gp91 ds-tat (50 μM) and the NO synthase inhibitor L-NAME (1 mM) both significantly lowered superoxide generation in failing heart homogenates by 80% and 76%, respectively. G6PD was upregulated and its activity higher in heart failure compared to control (0.61 ± 0.10 vs. 0.24 ± 0.03 nmol/min/mg protein, P < 0.05), while superoxide production decreased to normal levels in the presence of the G6PD inhibitor 6-aminonicotinamide. We conclude that the activation of myocardial G6PD is a novel mechanism that enhances NADPH availability and fuels superoxide-generating enzymes in heart failure.

Research paper thumbnail of Altered expression of a limited number of genes contributes to cardiac decompensation during chronic ventricular tachypacing in dogs

Physiological Genomics, 2006

Our aim was to determine the changes in the gene expression profile occurring during the transiti... more Our aim was to determine the changes in the gene expression profile occurring during the transition from compensated dysfunction (CD) to decompensated heart failure (HF) in pacinginduced dilated cardiomyopathy. Twelve chronically instrumented dogs underwent left ventricular pacing at 210 beats/min for 3 weeks and at 240 beats thereafter and 4 normal dogs were used as control. The transition from CD to HF occurred between the 3 rd to 4 th week of pacing, with end-stage HF at 28±1 days. RNA was extracted from left ventricular tissue at control, 3 and 4 weeks of pacing (n=4) and tested with the Affymetrix Canine Array. 509 genes were differentially expressed in CD versus control (PE0.05; fold change F ±2), with 362 increasing and 147 decreasing. 526 genes were differentially expressed in HF versus control (PE0.05; fold change F ±2), with 439 increasing and 87 decreasing. To better understand the transition, we compared gene alterations at 3 versus 4 weeks pacing and found that only 30 genes differed (P 0.05; fold change of ±2). We conclude that a number of processes including normalization of gene regulation during decompensation, appearance of new up-regulated genes and maintenance of gene expression all contribute to the transition to overt heart failure with an unexpectedly small number of genes differentially regulated.

Research paper thumbnail of Differential cardiac gene expression in atorvastatin-treated dogs

The Faseb Journal, Apr 1, 2007

Research paper thumbnail of Recurrent TERT Promoter Mutations in Urothelial Carcinoma and Potential Clinical Applications

Annals of Diagnostic Pathology, 2015

Research paper thumbnail of COX-2 contributes to the maintenance of flow-induced dilation in arterioles of eNOS-knockout mice

AJP Heart and Circulatory Physiology

Our previous studies demonstrated that, in gracilis muscle arterioles of male mice deficient in t... more Our previous studies demonstrated that, in gracilis muscle arterioles of male mice deficient in the gene for endothelial nitric oxide synthase (eNOS), flow-induced dilation (FID) is mediated by endothelial PGs. Thus the present study aimed to identify the specific isoform of cyclooxygenase (COX) responsible for the compensatory mediation of FID in arterioles of eNOS-knockout (KO) mice. Experiments were conducted on gracilis muscle arterioles of male eNOS-KO and wild-type (WT) mice. Basal tone and magnitude of FID of arterioles were comparable in the two strains of mice. A role for COX isoforms in the mediation of the responses was assessed by use of valeryl salicylate (3 mM) and NS-398 (10 microM), inhibitors of COX-1 and COX-2, respectively. In eNOS-KO arterioles, valeryl salicylate or NS-398 alone inhibited FID (at maximal flow rate) by approximately 51% and approximately 58%, respectively. Administration of both inhibitors eliminated the dilation. In WT arterioles, inhibition of COX-2 did not significantly affect FID, whereas inhibition of COX-1 decreased the dilation by approximately 57%. The residual portion of the response was abolished by additional administration of Nomega-nitro-L-arginine methyl ester. Western blot analysis indicated a comparable content of COX-1 protein in arterioles of WT and eNOS-KO mice. COX-2 protein, which was not detectable in arterioles of WT mice, was strongly expressed in arterioles of eNOS-KO mice, together with an upregulation of COX-2 gene expression. Immunohistochemical staining confirmed the presence of COX-2 in the endothelium of eNOS-KO arterioles. In conclusion, COX-2-derived PGs are the mediators responsible for maintenance of FID in arterioles of eNOS-deficient mice.

Research paper thumbnail of Borrelia burgdorferi gene expression profiling with membrane-based arrays

Methods in Enzymology, 2002

... ELIAS, ALAN BARBOUR, ALGIS JASINSKAS, JORGE BENACH, LAURA KATONAH, JUSTIN RADOLF, MELISSA CAI... more ... ELIAS, ALAN BARBOUR, ALGIS JASINSKAS, JORGE BENACH, LAURA KATONAH, JUSTIN RADOLF, MELISSA CAIMANO, JON SKARE, KRISTEN ... variation in plasmid content among isolates and some of these extrachromosomal elements are lost on serial propagation. ...

Research paper thumbnail of Conservation of gene arrangement and an unusual organization of rRNA genes in the linear chromosomes of the Lyme disease spirochaetes Borrelia burgdorferi, B. garinii and B. afzelii

Microbiology, 1994

Physical maps of the chromosomes of the Lyme disease spirochaetes Borrelia garinii and Borrelia a... more Physical maps of the chromosomes of the Lyme disease spirochaetes Borrelia garinii and Borrelia afielii have been elucidated for the enzymes Cspl, SgrAl, I-Ceul, Smal, Eagl, BssHII, MluI and Apal by two-dimensional pulsed-field gel electrophoresis techniques. The maps contain 42 sites for B. garinii and 32 for B. afielii. The mapping studies showed that the two chromosomes are linear DNA molecules of 953 and 948 kbp, respectively. A comparison of the physical maps of B. garinii and B. afielii and the published map of the other Lyme disease spirochaete, Borrelia burgdorferi [Davidson, B. E. , MacDougall, J. & Saint Girons, 1. (1992) J Bacteriol 174,3766-37741 revealed that the three chromosomes have f e w endonuclease sites in common, apart from a cluster in rrl (encoding 23s rRNA) and rrs (encoding 165 rRNA).

Research paper thumbnail of Premature death and age-related cardiac dysfunction in male eNOS-knockout mice

Journal of Molecular and Cellular Cardiology, 2004

The aims of our study were to determine mortality, and age-and genotype-related cardiac phenotype... more The aims of our study were to determine mortality, and age-and genotype-related cardiac phenotype in endothelial nitric oxide synthase (NOS) knockout (-/-) and wild-type (+/+) mice. Male and female (-/-) and male and female (+/+) conscious mice were studied at different ages by echocardiography and tail-cuff blood pressure (BP) measurement. Only 50% male (-/-) mice lived longer than 21 months whereas 89% (+/+) mice were still alive after 24 months (P < 0.005). There was little mortality in female mice of either genotype. Both (-/-) and (+/+) male mice have normal cardiac dimensions and function at 5.5 months. However, (-/-) mice developed cardiac dilation and dysfunction at 21 months as evidenced by a significant increase (P < 0.05) in left ventricular (LV) end-diastolic diameter from 2.69 ± 0.13 to 3.13 ± 0.09 mm, LV end-systolic diameter from 1.28 ± 0.11 to 1.86 ± 0.12 mm, LV end-diastolic cavity volume from 21 ± 2.8 to 31 ± 2.5 µl and LV mass from 19 ± 2.5 to 27 ± 1.9 mg/10 g and a significant decrease (P < 0.05) in ejection fraction (from 65 ± 3.3% to 41 ± 4.6%), shortening fraction (from 53 ± 2.2% to 41 ± 3.4%), LV posterior wall thickening (from 27 ± 2% to 12 ± 4%) and septum thickening (from 27 ± 2% to 12 ± 4%) compared with those at 5.5 months. There was a clear increase in cardiac weight and cardiac dilation by hematoxylin and eosin in male (-/-) mice at 21 months. BP in male (-/-) mice fell with the cardiac dysfunction, whereas female (-/-) mice were hypertensive even at 21 months. The level of mRNA for neuronal NOS and inducible NOS was greater in all females compared to males. These results indicate that male (-/-) mice have a significantly shorter lifespan than (+/+) or female mice, and male (-/-) mice develop cardiac dysfunction with age.

Research paper thumbnail of Comparative Transcriptional Profiling of Borrelia burgdorferi Clinical Isolates Differing in Capacities for Hematogenous Dissemination

Infection and Immunity, 2005

Borrelia burgdorferi, the etiologic agent of Lyme disease, is genetically heterogeneous. Previous... more Borrelia burgdorferi, the etiologic agent of Lyme disease, is genetically heterogeneous. Previous studies have shown a significant association between the frequency of hematogenous dissemination in Lyme disease patients and the genotype of the infecting B. burgdorferi strain. Comparative transcriptional profiling of two representative clinical isolates with distinct genotypes (BL206 and B356) was undertaken. A total of 78 open reading frames (ORFs) had expression levels that differed significantly between the two isolates. A number of genes with potential involvement in nutrient uptake (BB0603, BBA74, BB0329, BB0330, and BBB29) have significantly higher expression levels in isolate B356. Moreover, nearly 25% of the differentially expressed genes are predicted to be localized on the cell surface, implying that these two isolates have cell surface properties that differ considerably. One of these genes, BBA74, encodes a protein of 257 amino acid residues that has been shown to possess porin activity. BBA74 transcript level was >20-fold higher in B356 than in BL206, and strain B356 contained three-to fivefold more BBA74 protein. BBA74 was disrupted by the insertion of a kanamycin resistance cassette into the coding region. The growth rates of both wild-type and mutant strains were essentially identical, and cultures reached the same final cell densities. However, the mutant strains consistently showed prolonged lags of 2 to 5 days prior to the induction of log-phase growth compared to wild-type strains. It is tempting to speculate that the absence of BBA74 interferes with the enhanced nutrient uptake that may be required for the entry of cells into log-phase growth. These studies demonstrate the value of comparative transcriptional profiling for identifying differences in the transcriptomes of B. burgdorferi clinical isolates that may provide clues to pathogenesis. The 78 ORFs identified here are a good starting point for the investigation of factors involved in the hematogenous dissemination of B. burgdorferi.

Research paper thumbnail of Profiling of Temperature-Induced Changes in Borrelia burgdorferi Gene Expression by Using Whole Genome Arrays

Infection and Immunity, 2003

Borrelia burgdorferi is the etiologic agent of Lyme disease, the most prevalent arthropod-borne d... more Borrelia burgdorferi is the etiologic agent of Lyme disease, the most prevalent arthropod-borne disease in the United States. The genome of the type strain, B31, consists of a 910,725-bp linear chromosome and 21 linear and circular plasmids comprising 610,694 bp. During its life cycle, the spirochete exists in distinctly different environments, cycling between a tick vector and a mammalian host. Temperature is one environmental factor known to affect B. burgdorferi gene expression. To identify temperature-responsive genes, genome arrays containing 1,662 putative B. burgdorferi open reading frames (ORFs) were prepared on nylon membranes and employed to assess gene expression in B. burgdorferi B31 grown at 23 and 35°C. Differences in expression of more than 3.5 orders of magnitude could be readily discerned and quantitated. At least minimal expression from 91% of the arrayed ORFs could be detected. A total of 215 ORFs were differentially expressed at the two temperatures; 133 were expressed at significantly greater levels at 35°C, and 82 were more significantly expressed at 23°C. Of these 215 ORFs, 134 are characterized as genes of unknown function. One hundred thirty-six (63%) of the differentially expressed genes are plasmid encoded. Of particular interest is plasmid lp54 which contains 76 annotated putative genes; 31 of these exhibit temperature-regulated expression. These findings underscore the important role plasmid-encoded genes may play in adjustment of B. burgdorferi to growth under diverse environmental conditions.

Research paper thumbnail of Abstract 704: Cardiac Progenitor Cell Aging Is Responsible for Organ Aging

Circulation, Oct 31, 2007

Research paper thumbnail of Long-term methionine-diet induced mild hyperhomocysteinemia associated cardiac metabolic dysfunction in multiparous rats

Physiological Reports, 2015

Mild hyperhomocysteinemia (HHcy, clinically defined as less than 30 lmol/L) is an independent car... more Mild hyperhomocysteinemia (HHcy, clinically defined as less than 30 lmol/L) is an independent cardiovascular disease (CVD) risk factor, and is associated with many complications during pregnancy, such as preeclampsia (PE). The aim of this study was to assess the effect of long-term mild HHcy on cardiac metabolic function of multiparous rats. Female rats were mated 3 to 4 times and were fed with methionine in drinking water to increase plasma Hcy (2.9 AE 0.3 to 10.5 AE 2.3 lmol/L) until termination. This caused significant increase of heart weight/body weight (0.24 AE 0.01 to 0.27 AE 0.01 g/100 g) and left ventricle weight (0.69 AE 0.03 to 0.78 AE 0.01 g). Superoxide production was increased by 2.5-fold in HHcy hearts using lucigenin chemiluminescence. The ability of bradykinin and carbachol to regulate myocardial oxygen consumption (MVO 2 ) in vitro was impaired by 59% and 66% in HHcy heart, and it was restored by ascorbic acid (AA), tempol, or apocynin (Apo). Protein expression of p22 phox subunit of NAD(P)H oxidase was increased by 2.6-fold, but there were no changes in other NAD(P)H oxidase subunits, NOSs or SODs. Microarray revealed 1518 genes to be differentially regulated (P < 0.05). The mRNA level of NAD(P)H oxidase subunits, NOSs or SODs remained unchanged. In conclusion, long-term mild HHcy increases cardiac superoxide mainly through regulation of p22 phox component of the NAD(P)H oxidase and impairs the ability of NO to regulate MVO 2 in heart of multiparous mothers.

Research paper thumbnail of Identification of a novel clone, ST736, among Enterococcus faecium clinical isolates and its association with daptomycin nonsusceptibility

Antimicrobial agents and chemotherapy, 2014

Resistance to daptomycin in enterococcal clinical isolates remains rare but is being increasingly... more Resistance to daptomycin in enterococcal clinical isolates remains rare but is being increasingly reported in the United States and worldwide. There are limited data on the genetic relatedness and microbiological and clinical characteristics of daptomycin-nonsusceptible enterococcal clinical isolates. In this study, we assessed the population genetics of daptomycin-nonsusceptible Enterococcus faecium (DNSE) clinical isolates by multilocus sequence typing (MLST) and whole-genome sequencing analysis. Forty-two nonduplicate DNSE isolates and 43 randomly selected daptomycin-susceptible E. faecium isolates were included in the analysis. All E. faecium isolates were recovered from patients at a tertiary care medical center in suburban New York City from May 2009 through December 2013. The daptomycin MICs of the DNSE isolates ranged from 6 to >256 μg/ml. Three major clones of E. faecium (ST18, ST412, and ST736) were identified among these clinical isolates by MLST and whole-genome seque...

Research paper thumbnail of Oxidant-NO dependent gene regulation in dogs with type I diabetes: impact on cardiac function and metabolism

Cardiovascular diabetology, 2010

The mechanisms responsible for the cardiovascular mortality in type I diabetes (DM) have not been... more The mechanisms responsible for the cardiovascular mortality in type I diabetes (DM) have not been defined completely. We have shown in conscious dogs with DM that: 1) baseline coronary blood flow (CBF) was significantly decreased, 2) endothelium-dependent (ACh) coronary vasodilation was impaired, and 3) reflex cholinergic NO-dependent coronary vasodilation was selectively depressed. The most likely mechanism responsible for the depressed reflex cholinergic NO-dependent coronary vasodilation was the decreased bioactivity of NO from the vascular endothelium. The goal of this study was to investigate changes in cardiac gene expression in a canine model of alloxan-induced type 1 diabetes. Mongrel dogs were chronically instrumented and the dogs were divided into two groups: one normal and the other diabetic. In the diabetic group, the dogs were injected with alloxan monohydrate (40-60 mg/kg iv) over 1 min. The global changes in cardiac gene expression in dogs with alloxan-induced diabete...

Research paper thumbnail of Genome Sequence of Borrelia chilensis VA1, a South American Member of the Lyme Borreliosis Group

Genome Announcements, 2015

Borrelia chilensis strain VA1 is a recently described South American member of the Borrelia burgd... more Borrelia chilensis strain VA1 is a recently described South American member of the Borrelia burgdorferi sensu lato complex from Chile. Whole-genome sequencing analysis determined its linear chromosome and plasmids lp54 and cp26, confirmed its membership in the Lyme borreliosis group, and will open new research avenues regarding its pathogenic potential.

Research paper thumbnail of Identification of a coronary vascular progenitor cell in the human heart

Proceedings of the National Academy of Sciences, 2009

Primitive cells capable of generating small resistance arterioles and capillary structures in the... more Primitive cells capable of generating small resistance arterioles and capillary structures in the injured myocardium have been identified repeatedly. However, these cells do not form large conductive coronary arteries that would have important implications in the management of the ischemic heart. In the current study, we determined whether the human heart possesses a class of progenitor cells that regulates the growth of endothelial cells (ECs) and smooth muscle cells (SMCs) and vasculogenesis. The expression of vascular endothelial growth-factor receptor 2 (KDR) was used, together with the stem cell antigen c-kit, to isolate and expand a resident coronary vascular progenitor cell (VPC) from human myocardial samples. Structurally, vascular niches composed of c-kit-KDR-positive VPCs were identified within the walls of coronary vessels. The VPCs were connected by gap junctions to ECs, SMCs, and fibroblasts that operate as supporting cells. In vitro, VPCs were self-renewing and clonogenic and differentiated predominantly into ECs and SMCs and partly into cardiomyocytes. To establish the functional import of VPCs, a critical stenosis was created in immunosuppressed dogs, and tagged human VPCs were injected in proximity to the constricted artery. One month later, there was an increase in coronary blood flow (CBF) distal to the stenotic artery, resulting in functional improvement of the ischemic myocardium. Regenerated large, intermediate, and small human coronary arteries and capillaries were found. In conclusion, the human heart contains a pool of VPCs that can be implemented clinically to form functionally competent coronary vessels and improve CBF in patients with ischemic cardiomyopathy.

Research paper thumbnail of Notch1 regulates the fate of cardiac progenitor cells

Proceedings of the National Academy of Sciences, 2008

This article contains supporting information online at www.pnas.org/cgi/content/full/ 0808357105/... more This article contains supporting information online at www.pnas.org/cgi/content/full/ 0808357105/DCSupplemental.

Research paper thumbnail of Altered expression of a limited number of genes contributes to cardiac decompensation during chronic ventricular tachypacing in dogs

Physiological genomics, Jan 14, 2007

Our aim was to determine the changes in the gene expression profile occurring during the transiti... more Our aim was to determine the changes in the gene expression profile occurring during the transition from compensated dysfunction (CD) to decompensated heart failure (HF) in pacing-induced dilated cardiomyopathy. Twelve chronically instrumented dogs underwent left ventricular pacing at 210 beats/min for 3 wk and at 240 beats thereafter, and four normal dogs were used as control. The transition from CD to HF occurred between the 3rd and 4th wk of pacing, with end-stage HF at 28 +/- 1 days. RNA was extracted from left ventricular tissue at control and 3 and 4 wk of pacing (n = 4) and tested with the Affymetrix Canine Array. We found 509 genes differentially expressed in CD vs. control (P < or = 0.05, fold change > or = +/-2), with 362 increasing and 147 decreasing; 526 genes were differentially expressed in HF vs. control (P < or = 0.05; fold change > or = +/-2), with 439 increasing and 87 decreasing. To better understand the transition, we compared gene alterations at 3 vs...

Research paper thumbnail of CYP2C29 Produces Superoxide in Response to Shear Stress

Microcirculation, 2012

Activation of CYP2C29 releases superoxide during shear stress-induced dilation (SSID). Mesenteric... more Activation of CYP2C29 releases superoxide during shear stress-induced dilation (SSID). Mesenteric arteries isolated from female eNOS-KO and WT mice were cannulated and pressurized. Vasodilation and superoxide production in response to shear stress were assessed. Shear stress-induced dilation was significantly attenuated in vessels of eNOS-KO compared with WT mice, which was normalized by tempol and PEG-Catalase, in a PPOH (inhibitor of CYP2C29)-sensitive manner, but remained unaffected by VAS2870 and allopurinol, inhibitors of NADPH oxidase and xanthine oxidase, respectively. NaNO(2)-induced dilation was comparable in both strains of mice. Confocal microscopy shows that SS-stimulated superoxide was increased particularly in the endothelium of eNOS-KO mice. HPLC analysis of 2-EOH indicated an increase in SS-stimulated superoxide in vessels of eNOS-KO mice, a response that was sensitive to PPOH. Inhibition of soluble epoxide hydrolase significantly enhanced SSID without affecting SS-stimulated superoxide production. CYP2C29 and catalase were upregulated, and exogenous H(2)O(2) caused vasoconstriction in vessels of eNOS-KO mice. CYP2C29 synthesizes EETs to mediate SSID, and simultaneously releases superoxide and sequential H(2)O(2), which in turn impair SSID.

Research paper thumbnail of Premature death and age-related cardiac dysfunction in male eNOS-knockout mice

Journal of Molecular and Cellular Cardiology, 2004

The aims of our study were to determine mortality, and age-and genotype-related cardiac phenotype... more The aims of our study were to determine mortality, and age-and genotype-related cardiac phenotype in endothelial nitric oxide synthase (NOS) knockout (-/-) and wild-type (+/+) mice. Male and female (-/-) and male and female (+/+) conscious mice were studied at different ages by echocardiography and tail-cuff blood pressure (BP) measurement. Only 50% male (-/-) mice lived longer than 21 months whereas 89% (+/+) mice were still alive after 24 months (P < 0.005). There was little mortality in female mice of either genotype. Both (-/-) and (+/+) male mice have normal cardiac dimensions and function at 5.5 months. However, (-/-) mice developed cardiac dilation and dysfunction at 21 months as evidenced by a significant increase (P < 0.05) in left ventricular (LV) end-diastolic diameter from 2.69 ± 0.13 to 3.13 ± 0.09 mm, LV end-systolic diameter from 1.28 ± 0.11 to 1.86 ± 0.12 mm, LV end-diastolic cavity volume from 21 ± 2.8 to 31 ± 2.5 µl and LV mass from 19 ± 2.5 to 27 ± 1.9 mg/10 g and a significant decrease (P < 0.05) in ejection fraction (from 65 ± 3.3% to 41 ± 4.6%), shortening fraction (from 53 ± 2.2% to 41 ± 3.4%), LV posterior wall thickening (from 27 ± 2% to 12 ± 4%) and septum thickening (from 27 ± 2% to 12 ± 4%) compared with those at 5.5 months. There was a clear increase in cardiac weight and cardiac dilation by hematoxylin and eosin in male (-/-) mice at 21 months. BP in male (-/-) mice fell with the cardiac dysfunction, whereas female (-/-) mice were hypertensive even at 21 months. The level of mRNA for neuronal NOS and inducible NOS was greater in all females compared to males. These results indicate that male (-/-) mice have a significantly shorter lifespan than (+/+) or female mice, and male (-/-) mice develop cardiac dysfunction with age.

Research paper thumbnail of Glucose-6-phosphate dehydrogenase-derived NADPH fuels superoxide production in the failing heart

Journal of Molecular and Cellular Cardiology, 2006

In the failing heart, NADPH oxidase and uncoupled NO synthase utilize cytosolic NADPH to form sup... more In the failing heart, NADPH oxidase and uncoupled NO synthase utilize cytosolic NADPH to form superoxide. NADPH is supplied principally by the pentose phosphate pathway, whose rate-limiting enzyme is glucose 6-phosphate dehydrogenase (G6PD). Therefore, we hypothesized that cardiac G6PD activation drives part of the excessive superoxide production implicated in the pathogenesis of heart failure. Pacing-induced heart failure was performed in eight chronically instrumented dogs. Seven normal dogs served as control. End-stage failure occurred after 28 ± 1 days of pacing, when left ventricular end-diastolic pressure reached 25 mm Hg. In left ventricular tissue homogenates, spontaneous superoxide generation measured by lucigenin (5 μM) chemiluminescence was markedly increased in heart failure (1338 ± 419 vs. 419 ± 102 AU/mg protein, P < 0.05), as were NADPH levels (15.4 ± 1.5 vs. 7.5 ± 1.5 μmol/gww, P < 0.05). Superoxide production was further stimulated by the addition of NADPH. The NADPH oxidase inhibitor gp91 ds-tat (50 μM) and the NO synthase inhibitor L-NAME (1 mM) both significantly lowered superoxide generation in failing heart homogenates by 80% and 76%, respectively. G6PD was upregulated and its activity higher in heart failure compared to control (0.61 ± 0.10 vs. 0.24 ± 0.03 nmol/min/mg protein, P < 0.05), while superoxide production decreased to normal levels in the presence of the G6PD inhibitor 6-aminonicotinamide. We conclude that the activation of myocardial G6PD is a novel mechanism that enhances NADPH availability and fuels superoxide-generating enzymes in heart failure.