scholarly journals Candida albicans RIM101 pH Response Pathway Is Required for Host-Pathogen Interactions

2000 ◽  
Vol 68 (10) ◽  
pp. 5953-5959 ◽  
Author(s):  
Dana Davis ◽  
John E. Edwards ◽  
Aaron P. Mitchell ◽  
Ashraf S. Ibrahim
Keyword(s):  
Gene Expression ◽  
Endothelial Cells ◽  
Candida Albicans ◽  
Marked Reduction ◽  
Endothelial Damage ◽  
Systemic Candidiasis ◽  
Ph Response

ABSTRACT The ability of Candida albicans to respond to diverse environments is critical for its success as a pathogen. TheRIM101 pathway controls gene expression and the yeast-to-hyphal transition in C. albicans in response to changes in environmental pH in vitro. In this study, we found that theRIM101 pathway is necessary in vivo for pathogenesis. First, we show thatrim101−/rim101− andrim8−/rim8− mutants have a significant reduction in virulence using the mouse model of hematogenously disseminated systemic candidiasis. Second, these mutants show a marked reduction in kidney pathology. Third, therim101−/rim101− andrim8−/rim8− mutants show defects in the ability to damage endothelial cells in situ. Finally, we show that an activated allele of RIM101, RIM101-405, is a suppressor of the rim8− mutation in vivo as it rescues the virulence, histological, and endothelial damage defects of the rim8−/rim8− mutant. These results demonstrate that the RIM101 pathway is required for C. albicans virulence in vivo and that the function of Rim8p in pathogenesis is to activate Rim101p.

Expression of MMP-8 and MMP-13 Genes in the Periodontal Ligament during Tooth Movement in Rats

2003 ◽  
Vol 82 (8) ◽  
pp. 646-651 ◽  
Author(s):  
I. Takahashi ◽  
M. Nishimura ◽  
K. Onodera ◽  
J.-W. Bae ◽  
H. Mitani ◽  
...  
Keyword(s):  
Gene Expression ◽  
Periodontal Ligament ◽  
Tooth Movement ◽  
Orthodontic Tooth Movement ◽  
Polymerase Chain Reaction Analysis ◽  
Tension And Compression ◽  
Polymerase Chain

Periodontal ligament tissue is remodeled on both the tension and compression sides of moving teeth during orthodontic tooth movement. The present study was designed to clarify the hypothesis that the expression of MMP-8 and MMP-13 mRNA is promoted during the remodeling of periodontal ligament tissue in orthodontic tooth movement. We used the in situ hybridization method and semi-quantitative reverse-transcription/polymerase chain-reaction analysis to elucidate the gene expression of MMP-8 and MMP-13 mRNA. Expression of MMP-8 and MMP-13 mRNA transiently increased on both the compression and tension sides during active tooth movement in vivo. The gene expression of MMP-8 and MMP-13 was induced by tension, while compression indirectly promoted the gene expression of MMP-8 and MMP-13 through soluble factors in vitro. Thus, we concluded that the expression of MMP-8 and MMP-13 is differentially regulated by tension and compression, and plays an important role in the remodeling of the periodontal ligament.

Bidirectional Oscillatory Shear Stress Increases Pro-Atherogenic Gene Expressions (I-CAM1, E-Selectin and IL-6) in Endothelial Cells

2011 ◽  
Author(s):  
Amlan Chakraborty ◽  
Venkatakrishna R. Jala ◽  
Sutirtha Chakraborty ◽  
R. Eric Berson ◽  
M. Keith Sharp ◽  
...  
Keyword(s):  
Gene Expression ◽  
Endothelial Cells ◽  
Shear Stress ◽  
Atherosclerotic Plaque ◽  
Inflammatory Diseases ◽  
Leukotriene B4 ◽  
Oscillatory Shear ◽  
Gene Expressions

Wall shear stress (WSS) plays a key role in altering intracellular pathways and gene expression of endothelial cells, and has significant impacts on atherosclerotic plaque development (1–3). Further, the atherogenic regulators Leukotriene B4 (LTB4) and Lipopolysaccharide (LPS) have significant impacts on the pathophysiology of many inflammatory diseases. This study investigates the effects of oscillatory shear directionality on pro-atherogenic gene expression (I-CAM, E-Selectin, and IL-6) in the presence of LTB4 and LPS. An orbital shaker was used to expose the endothelial cells to oscillatory shear in culture dishes, and Computational fluid dynamics (CFD) was applied to quantify the shear stress on the bottom of the orbiting dish. Directionality of oscillatory shear was characterized by a newly developed hemodynamic parameter — Directional oscillatory shear index (DOSI), which was demonstrated in a previous study to significantly impact cell morphology (4). Results showed that DOSI significantly altered gene expression. Therefore, directionality of shear modulates atherosclerotic gene expression in vitro and thus, may influence the formation of atherosclerotic plaque in vivo.

scholarly journals Adhesion of Candida albicans to Endothelial Cells under Physiological Conditions of Flow

2009 ◽  
Vol 77 (9) ◽  
pp. 3872-3878 ◽  
Author(s):  
Sarah E. W. Grubb ◽  
Craig Murdoch ◽  
Peter E. Sudbery ◽  
Stephen P. Saville ◽  
Jose L. Lopez-Ribot ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Shear Stress ◽  
Candida Albicans ◽  
Blood Vessels ◽  
Systemic Infection ◽  
Multiple Organ ◽  
Adhesion Assay ◽  
Conflicting Evidence

ABSTRACT Candida albicans is a commensal organism that under certain circumstances can become pathogenic. During systemic infection C. albicans is disseminated via the circulation to distant organs, where it causes multiple organ failure. Despite the severity of systemic C. albicans infection, little is known about the mechanisms involved in the adhesion of this organism to the endothelium lining blood vessels. Previous studies have used static assays to examine adhesion. However, these do not realistically model blood vessels, where circulating C. albicans cells must adhere to the endothelium under conditions of flow and shear stress. Furthermore, there is conflicting evidence concerning the role played by yeast, pseudohyphal, and hyphal forms of C. albicans in adhesion to endothelium. To test the hypothesis that there may be differences in the abilities of these three morphogenic forms of C. albicans to adhere to endothelium under conditions of flow, we developed an in vitro flow adhesion assay. We found that all three forms of C. albicans rapidly bound to confluent endothelial cells under conditions of flow. Maximum adhesion was found at low shear stress levels similar to that found in postcapillary venules. Moreover, yeast forms bound in significantly greater numbers than did pseudohyphal and hyphal forms, respectively, contrasting with previous findings from static assays. These findings are consistent with recent in vivo data suggesting that yeast forms may be capable of adhering to the endothelium and migrating into the tissues before undergoing morphogenic change to cause tissue damage.

scholarly journals Elevated expression of NEU1 sialidase in idiopathic pulmonary fibrosis provokes pulmonary collagen deposition, lymphocytosis, and fibrosis

2016 ◽  
Vol 310 (10) ◽  
pp. L940-L954 ◽  
Author(s):  
Irina G. Luzina ◽  
Virginia Lockatell ◽  
Sang W. Hyun ◽  
Pavel Kopach ◽  
Phillip H. Kang ◽  
...  
Keyword(s):  
Gene Expression ◽  
Endothelial Cells ◽  
Idiopathic Pulmonary Fibrosis ◽  
Pulmonary Fibrosis ◽  
Molecular Mechanisms ◽  
Transforming Growth Factor ◽  
Recombinant Adenovirus ◽  
Global Gene Expression

Idiopathic pulmonary fibrosis (IPF) poses challenges to understanding its underlying cellular and molecular mechanisms and the development of better therapies. Previous studies suggest a pathophysiological role for neuraminidase 1 (NEU1), an enzyme that removes terminal sialic acid from glycoproteins. We observed increased NEU1 expression in epithelial and endothelial cells, as well as fibroblasts, in the lungs of patients with IPF compared with healthy control lungs. Recombinant adenovirus-mediated gene delivery of NEU1 to cultured primary human cells elicited profound changes in cellular phenotypes. Small airway epithelial cell migration was impaired in wounding assays, whereas, in pulmonary microvascular endothelial cells, NEU1 overexpression strongly impacted global gene expression, increased T cell adhesion to endothelial monolayers, and disrupted endothelial capillary-like tube formation. NEU1 overexpression in fibroblasts provoked increased levels of collagen types I and III, substantial changes in global gene expression, and accelerated degradation of matrix metalloproteinase-14. Intratracheal instillation of NEU1 encoding, but not control adenovirus, induced lymphocyte accumulation in bronchoalveolar lavage samples and lung tissues and elevations of pulmonary transforming growth factor-β and collagen. The lymphocytes were predominantly T cells, with CD8+ cells exceeding CD4+ cells by nearly twofold. These combined data indicate that elevated NEU1 expression alters functional activities of distinct lung cell types in vitro and recapitulates lymphocytic infiltration and collagen accumulation in vivo, consistent with mechanisms implicated in lung fibrosis.

scholarly journals Effect of Farnesol on a Mouse Model of Systemic Candidiasis, Determined by Use of a DPP3 Knockout Mutant of Candida albicans

2007 ◽  
Vol 75 (4) ◽  
pp. 1609-1618 ◽  
Author(s):  
Dhammika H. M. L. P. Navarathna ◽  
Jacob M. Hornby ◽  
Navasona Krishnan ◽  
Anne Parkhurst ◽  
Gerald E. Duhamel ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Mouse Model ◽  
Tween 80 ◽  
Sublethal Dose ◽  
Systemic Candidiasis ◽  
Knockout Mutant ◽  
Gene Encoding

ABSTRACTThis work extends our previous observation that the fungusCandida albicanssecretes micromolar levels of farnesol and that accumulation of farnesol in vitro prevents the yeast-to-mycelium conversion in a quorum-sensing manner. What does farnesol do in vivo? The purpose of this study was to determine the role of farnesol during infection with a well-established mouse model of systemic candidiasis withC. albicansA72 administered by tail vein injection. This question was addressed by altering both endogenous and exogenous farnesol. For endogenous farnesol, we created a knockout mutation inDPP3, the gene encoding a phosphatase which converts farnesyl pyrophosphate to farnesol. This mutant (KWN2) produced six times less farnesol and was ca. 4.2 times less pathogenic than its SN152 parent. The strain withDPP3reconstituted (KWN4) regained both its farnesol production levels and pathogenicity. These mutants (KWN1 to KWN4) retained their full dimorphic capability. With regard to exogenous farnesol, farnesol was administered either intraperitoneally (i.p.) or orally in the drinking water. Mice receivingC. albicansintravenously and farnesol (20 mM) orally had enhanced mortality (P< 0.03). Similarly, mice (n= 40) injected with 1.0 ml of 20 mM farnesol i.p. had enhanced mortality (P< 0.03), and the onset of mortality was 30 h sooner than for mice which received a control injection without farnesol. The effect of i.p. farnesol was more pronounced (P< 0.04) when mice were inoculated with a sublethal dose ofC. albicans. These mice started to die 4 days earlier, and the percent survival on day 6 postinoculation (p.i.) was five times lower than for mice receivingC. albicanswith control i.p. injections. In all experiments, mice administered farnesol alone or Tween 80 alone remained normal throughout a 14-day observation period. Finally, beginning at 12 h p.i., higher numbers ofC. albicanscells were detected in kidneys from mice receiving i.p. farnesol than in those from mice receiving control i.p. injections. Thus, reduced endogenous farnesol decreased virulence, while providing exogenous farnesol increased virulence. Taken together, these data suggest that farnesol may play a role in disease pathogenesis, either directly or indirectly, and thus may represent a newly identified virulence factor.

scholarly journals Time Course of Microbiologic Outcome and Gene Expression in Candida albicans during and following In Vitro and In Vivo Exposure to Fluconazole

2006 ◽  
Vol 50 (4) ◽  
pp. 1311-1319 ◽  
Author(s):  
A. Lepak ◽  
J. Nett ◽  
L. Lincoln ◽  
K. Marchillo ◽  
D. Andes
Keyword(s):  
Gene Expression ◽  
Candida Albicans ◽  
Time Course ◽  
Dependent Manner ◽  
Time Points ◽  
In Vivo Expression ◽  
The Impact ◽  
The Relationship

ABSTRACT Pharmacodynamics (PD) considers the relationship between drug exposure and effect. The two factors that have been used to distinguish the PD behaviors of antimicrobials are the impact of concentration on the extent of organism killing and the duration of persistent microbiologic suppression (postantibiotic effect). The goals of these studies were (i) to examine the relationship between antimicrobial PD and gene expression and (ii) to gain insight into the mechanism of fluconazole effects persisting following exposure. Microarrays were used to estimate the transcriptional response of Candida albicans to a supra-MIC F exposure over time in vitro. Fluconazole at four times the MIC was added to a log-phase C. albicans culture, and cells were collected to determine viable growth and for microarray analyses. We identified differential expression of 18% of all genes for at least one of the time points. More genes were upregulated (n = 1,053 [16%]) than downregulated (174 [3%]). Of genes with known function that were upregulated during exposure, most were related to plasma membrane/cell wall synthesis (18%), stress responses (7%), and metabolism (6%). The categories of downregulated genes during exposure included protein synthesis (15%), DNA synthesis/repair (7%), and transport (7%) genes. The majority of genes identified at the postexposure time points were from the protein (17%) and DNA (7%) synthesis categories. In subsequent studies, three genes (CDR1, CDR2, and ERG11) were examined in greater detail (more concentration and time points) following fluconazole exposure in vitro and in vivo. Expression levels from the in vitro and in vivo studies were congruent. CDR1 and CDR2 transcripts were reduced during in vitro fluconazole exposure and during supra-MIC exposure in vivo. However, in the postexposure period, the mRNA abundance of both pumps increased. ERG11 expression increased during exposure and fell in the postexposure period. The expression of the three genes responded in a dose-dependent manner. In sum, the microarray data obtained during and following fluconazole exposure identified genes both known and unknown to be affected by this drug class. The expanded in vitro and in vivo expression data set underscores the importance of considering the time course of exposure in pharmacogenomic investigations.

scholarly journals Tetracycline-Regulatable System To Tightly Control Gene Expression in the Pathogenic Fungus Candida albicans

2000 ◽  
Vol 68 (12) ◽  
pp. 6712-6719 ◽  
Author(s):  
Hironobu Nakayama ◽  
Toshiyuki Mio ◽  
Shigehisa Nagahashi ◽  
Michiko Kokado ◽  
Mikio Arisawa ◽  
...  
Keyword(s):  
Gene Expression ◽  
Candida Albicans ◽  
Culture Media ◽  
Pathogenic Fungus ◽  
Elongation Factor ◽  
Growth Defect ◽  
Control Gene ◽  
Control Gene Expression

ABSTRACT Conventional tools for elucidating gene function are relatively scarce in Candida albicans, the most prevalent human fungal pathogen. To this end, we developed a convenient system to control gene expression in C. albicans by the tetracycline-regulatable (TR) promoters. When the sea pansy Renilla reniformisluciferase gene (RLUC1) was placed under the control of this system, doxycycline (DOX) inhibited the luciferase activity almost completely. In the absence of DOX, the RLUC1 gene was induced to express luciferase at a level 400- to 1,000-fold higher than that in the presence of DOX. The same results were obtained in hypha-forming cells. The replacement ofN-myristoyltransferase or translation elongation factor 3 promoters with TR promoters conferred a DOX-dependent growth defect in culture media. Furthermore, all the mice infected with these mutants, which are still virulent, survived following DOX administration. Consistently, we observed that the number of these mutant cells recovered from the mouse kidneys was significantly reduced following DOX administration. Thus, this system is useful for investigating gene functions, since this system is able to function in both in vitro and in vivo settings.

Oxygen modulates alpha 1B-adrenergic receptor gene expression by arterial but not venous vascular smooth muscle

1996 ◽  
Vol 271 (4) ◽  
pp. H1599-H1608 ◽  
Author(s):  
A. D. Eckhart ◽  
Z. Zhu ◽  
W. J. Arendshorst ◽  
J. E. Faber
Keyword(s):  
Gene Expression ◽  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
In Vivo Models ◽  
Beta Actin ◽  
Actin Mrna ◽  
Alpha Actin

Blood and tissue O2 levels are major determinants of short-term autoregulatory adjustments in vascular smooth muscle cell (SMC) tension and may effect long-term alterations in SMC catecholamine responsiveness. We examined the hypothesis that prolonged hypoxia altered gene expression of alpha 1-adrenoceptors. After exposure of cultured aortic (in vitro) SMC to 3% O2 for 8 h, alpha 1B mRNA increased to 523% (P = 0.02) of control cells (21% O2) and to 205% (P = 0.04) in in situ organ-cultured aortic SMC. In vivo hypoxic hypoxia (10% inspired O2) similarly increased aortic SMC alpha 1B mRNA 180% (P = 0.02). In contrast, alpha 1D, alpha-actin and beta-actin mRNA levels were not changed in aortic SMC by low O2 in the in vitro, in situ, or in vivo models. Unlike aortic SMC, vena caval SMC alpha 1B mRNA expression did not change with low-O2 exposure in vitro or in vivo, nor did alpha 1D, alpha-actin or beta-actin mRNA. Aortic SMC alpha 1B transcription rate increased 360% (P = 0.02), whereas alpha 1D, alpha-actin, and beta-actin transcription was unchanged. Neither alpha 1B nor alpha 1D mRNA stability was altered by low-O2 exposure. Total alpha 1-adrenoceptor density ([3H]prazosin binding) increased 12% (P = 0.04) after 24 h of 3% O2. This was associated with a 200% increase (P < 0.01) in the chloroethylclonidine (CEC)-sensitive alpha 1-adrenoceptor population and no change in CEC-insensitive alpha 1-adrenoceptor density. Exposure of aortic SMC to 24 h of 3% O2 increased the maximum response of norepinephrine-evoked elevations in intracellular Ca2+ as measured using fura 2. Low O2 did not change responses to another G protein-coupled receptor, angiotensin II. These data suggest that reduced O2, during prolonged hypoxemia or tissue ischemia, may selectively increase expression of functionally coupled alpha 1B-adrenoceptors in arterial blood vessels.

scholarly journals Functional interactions of T cells with endothelial cells: the role of CD40L-CD40-mediated signals.

1995 ◽  
Vol 182 (6) ◽  
pp. 1857-1864 ◽  
Author(s):  
M J Yellin ◽  
J Brett ◽  
D Baum ◽  
A Matsushima ◽  
M Szabolcs ◽  
...  
Keyword(s):  
T Cells ◽  
Endothelial Cells ◽  
Endothelial Cell ◽  
Cell Surface ◽  
Cell Activation ◽  
Endothelial Cell Activation ◽  
Cd40 Expression

CD40 is expressed on a variety of cells, including B cells, monocytes, dendritic cells, and fibroblasts. CD40 interacts with CD40L, a 30-33-kD activation-induced CD4+ T cell surface molecule. CD40L-CD40 interactions are known to play key roles in B cell activation and differentiation in vitro and in vivo. We now report that normal human endothelial cells also express CD40 in situ, and CD40L-CD40 interactions induce endothelial cell activation in vitro. Frozen sections from normal spleen, thyroid, skin, muscle, kidney, lung, or umbilical cord were studied for CD40 expression by immunohistochemistry. Endothelial cells from all tissues studied express CD40 in situ. Moreover, human umbilical vein endothelial cells (HUVEC) express CD40 in vitro, and recombinant interferon gamma induces HUVEC CD40 upregulation. CD40 expression on HUVEC is functionally significant because CD40L+ Jurkat T cells or CD40L+ 293 kidney cell transfectants, but not control cells, upregulate HUVEC CD54 (intercellular adhesion molecule-1), CD62E (E-selectin), and CD106 (vascular cell adhesion molecule-1) expression in vitro. Moreover, the kinetics of CD40L-, interleukin 1-, or tumor necrosis factor alpha-induced CD54, CD62E, and CD106 upregulation on HUVEC are similar. Finally, CD40L-CD40 interactions do not induce CD80, CD86, or major histocompatibility complex class II expression on HUVEC in vitro. These results demonstrate that CD40L-CD40 interactions induce endothelial cell activation in vitro. Moreover, they suggest a mechanism by which activated CD4+ T cells may augment inflammatory responses in vivo by upregulating the expression of endothelial cell surface adhesion molecules.

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