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 Comparison between efficacy of allicin and fluconazole against Candida albicans in vitro and in a systemic candidiasis mouse model

2011 ◽  
Vol 315 (2) ◽  
pp. 87-93 ◽  
Author(s):  
Alireza Khodavandi ◽  
Fahimeh Alizadeh ◽  
Nabil S. Harmal ◽  
Shiran M. Sidik ◽  
Fauziah Othman ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Mouse Model ◽  
Systemic Candidiasis

scholarly journals Interleukin-6 (IL-6) Activates the NOTCH1 Signaling Pathway Through E-Proteins in Endometriotic Lesions

2020 ◽  
Vol 105 (5) ◽  
pp. 1316-1326
Author(s):  
Yong Song ◽  
Ren-Wei Su ◽  
Niraj R Joshi ◽  
Tae Hoon Kim ◽  
Bruce A Lessey ◽  
...  
Keyword(s):  
Mouse Model ◽  
Vehicle Group ◽  
E Proteins ◽  
Eutopic Endometrium ◽  
Baboon Model ◽  
Notch1 Signaling Pathway ◽  
Interfering Rna

Abstract Context NOTCH signaling is activated in endometriotic lesions, but the exact mechanisms remains unclear. IL-6, which is increased in the peritoneal fluid of women with endometriosis, induces NOTCH1 through E-proteins including E2A and HEB in cancer. Objective To study the role of E-proteins in inducing NOTCH1 expression under the regulation of IL-6 in endometriosis. Setting and Design The expression of E-proteins and NOTCH1 was first investigated in endometrium of women with endometriosis and the baboon model of endometriosis. Regulation of E-proteins and NOTCH1 expression was examined after IL-6 stimulation and siRNA mediated inhibition of E2A or/and HEB in human endometriotic epithelial cells (12Z) in vitro, and subsequently following IL-6 treatment in the mouse model of endometriosis in vivo. Results E2A, HEB, and NOTCH1 were significantly upregulated in glandular epithelium (GE) of ectopic endometrium compared to eutopic endometrium in both women and the baboon model. IL-6 treatment upregulated the expression of NOTCH1 together with E2A and HEB in 12Z cells. Small interfering RNA inhibition of E2A and HEB or HEB alone decreased NOTCH1 expression. Binding efficiency of both E2A and HEB was significantly higher at the binding sites on the human NOTCH1 promoter after IL-6 treatment. Finally, IL-6 treatment resulted in a significantly increased number of endometriotic lesions along with increased expression of E2A, HEB, and NOTCH1 in GE of the lesions compared with the vehicle group in an endometriosis mouse model. Conclusions IL-6 induced NOTCH1 expression is mediated by E-proteins in the ectopic GE cells, which may promote endometriotic lesion development.

Role of Il-2, Il-7, and IL-15 in T Cell Mediated Graft-vs-Leukemia Against Human Acute Lymphoblastic Leukemia in a NOD/scid Chimeric Mouse Model.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 5256-5256
Author(s):  
Doug Cipkala ◽  
Kelly McQuown ◽  
Lindsay Hendey ◽  
Michael Boyer
Keyword(s):  
Bone Marrow ◽  
Flow Cytometry ◽  
T Cells ◽  
Mouse Model ◽  
Scid Mouse ◽  
In Vitro Cytotoxicity ◽  
Scid Mouse Model

Abstract The use of cytotoxic T-lymphocytes (CTL) has been attempted experimentally with various tumors to achieve disease control. Factors that may influence GVT include CTL cytotoxicity, ability to home to disease sites, and survival of T cells in the host. The objective of our study is to evaluate the GVL effects of human alloreactive CTL against ALL in a chimeric NOD/scid mouse model. CTL were generated from random blood donor PBMCs stimulated with the 697 human ALL cell line and supplemented with IL-2, -7, or -15. CTL were analyzed for in vitro cytotoxicity against 697 cells, phenotype, and in vitro migration on day 14. NOD/scid mice were injected with 107 697 ALL cells followed by 5x106 CTL. Mice were sacrificed seven days following CTL injection and residual leukemia was measured in the bone marrow and spleen via flow cytometry. The ratios of CD8/CD4 positive T cells at the time of injection were 46/21% for IL-2, 52/31% for IL-7, and 45/14% for IL-15 cultured CTL (n=13). Control mice not receiving CTL had a baseline leukemia burden of 2.01% and 0.15% in the bone marrow and spleen, respectively (n=15). Mice treated with IL-15 cultured CTL had a reduction in tumor burden to 0.2% (n=13, p=0.01) and 0.05% (n=13, p=0.01) in bone marrow and spleen, respectively. Those treated with IL-2 or IL-7 cultured CTL showed no significant difference in leukemia burden in either the bone marrow (IL-2 1.28%, Il-7 5.97%) or spleen (IL-2 0.4%, IL-7 0.33%). No residual CTL could be identified in the bone marrow or spleen at the time of sacrifice in any CTL group. CTL grown in each cytokine resulted in similar in vitro cytotoxicity at an effector:target ratio of 10:1 (IL-2 41.3%, IL-7 37.7%, IL-15 45.3%, n=12–15, p&gt;0.05 for all groups) and had statistically similar intracellular perforin and granzyme-B expression. In vitro CTL migration to a human mesenchymal stem cell line was greatest with IL-15 CTL (30.5%, n=4), followed by IL-7 CTL (18.9%, n=4), and least in IL-2 CTL (17.9%, n=4), though the differences were not significant. In vitro CTL migration was analyzed to an SDF-1α gradient as CXCR4/SDF-1α interactions are necessary for hematopoietic progenitor cell homing to the bone marrow. IL-15 cultured CTL showed the highest migration (48.8%, n=8) as compared to IL-2 (21.7%, n=6, p=0.048) or IL-7 CTL (35.9%, n=8, p&gt;0.05). However, surface expression of CXCR4 measured by flow cytometry was significantly higher in IL-7 CTL (89.4%, n=9) compared to IL-2 CTL (52.2%, n=9, p&lt;0.001) and IL-15 CTL (65.4%, n=10, p=0.002). Experiments are currently underway to further evaluate the role of CXCR4/SDF-1α in GVL. Preliminary in vivo experiments do not suggest any significant differences in CTL engraftment when evaluated at 24 hours post injection. Expression of the anti-apoptotic bcl-2 protein was greatest on IL-7 (MFI=5295, n=13) and IL-15 (MFI=4865, n=14) when compared to IL-2 CTL (MFI=3530, n=13, p=0.02 vs. IL-7, p=0.05 vs. IL-15), suggesting an increased in vivo survival ability. We hypothesize that IL-15 cultured CTL have greater GVL effects due to either higher in vivo survival, greater bone marrow homing efficiency, or both. Future experiments are planned to evaluate in vivo administration of IL-2 to enhance CTL survival in the host. In conclusion, IL-15 cultured CTL had significantly greater in vivo GVL effects compared to IL-2 and IL-7 CTL in the NOD/scid mouse model. This model can be utilized to evaluate the mechanism of T cell mediated GVL against ALL and potentially other human malignancies.

scholarly journals Identification of the Putative Protein Phosphatase Gene PTC1 as a Virulence-Related Gene Using a Silkworm Model of Candida albicans Infection

2008 ◽  
Vol 7 (10) ◽  
pp. 1640-1648 ◽  
Author(s):  
Nozomu Hanaoka ◽  
Yukie Takano ◽  
Kazutoshi Shibuya ◽  
Hajime Fugo ◽  
Yoshimasa Uehara ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Mouse Model ◽  
Protein Phosphatase ◽  
Protein Phosphatases ◽  
Hyphal Growth ◽  
Marker Genes ◽  
Phenotypic Traits ◽  
Putative Protein

ABSTRACT Protein phosphatases are critical for the regulation of many cellular processes. Null mutants of 21 putative protein phosphatases of Candida albicans were constructed by consecutive allele replacement using the URA3 and ARG4 marker genes. A simple silkworm model of C. albicans infection was used to screen the panel of mutants. Four null mutant (cmp1Δ, yvh1Δ, sit4Δ, and ptc1Δ) strains showed attenuated virulence in the silkworm model relative to that of control and parental strains. Three of the mutants, the cmp1Δ, yvh1Δ, and sit4Δ mutants, had previously been identified as affecting virulence in a conventional mouse model, indicating the validity of the silkworm model screen. Disruption of the putative protein phosphatase gene PTC1 of C. albicans, which has 52% identity to the Saccharomyces cerevisiae type 2C protein phosphatase PTC1, significantly reduced virulence in the silkworm model. The mutant was also avirulent in a mouse model of disseminated candidiasis. Reintroducing either of the C. albicans PTC1 alleles into the disruptant strain, using a cassette containing either allele under the control of a constitutive ACT1 promoter, restored virulence in both infection models. Characterization of ptc1Δ revealed other phenotypic traits, including reduced hyphal growth in vitro and in vivo, and reduced extracellular proteolytic activity. We conclude that PTC1 may contribute to pathogenicity in C. albicans.

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.

scholarly journals Pharmacological Antagonism of Kainate Receptor Rescues Dysfunction and Loss of Dopamine Neurons in a Mouse Model of Human Parkin-induced Toxicity

2020 ◽  
Author(s):  
Maria Regoni ◽  
Stefano Cattaneo ◽  
Daniela Mercatelli ◽  
Salvatore Novello ◽  
Alice Passoni ◽  
...  
Keyword(s):  
Mouse Model ◽  
Neuroprotective Effect ◽  
Chronic Administration ◽  
Dopamine Neurons ◽  
Kainate Receptors ◽  
Substantia Nigra Pars Compacta ◽  
Gene Encoding ◽  
Neuroprotective Therapy

Abstract BackgroundMutations in the PARK2 gene encoding the protein parkin cause autosomal recessive juvenile parkinsonism (ARJP), a neurodegenerative disease characterized by dysfunction and death of dopamine (DA) neurons in the substantia nigra pars compacta. Since a neuroprotective therapy for ARJP does not exist, research efforts aimed at discovering potential targets for neuroprotection are critically needed.A previous study demonstrated that loss of parkin function or expression of parkin mutants associated with ARJP causesan accumulation of glutamate kainate receptors (KARs) in human brain tissues and an increase of KAR-mediated currents in neuronsin vitro. MethodsBased on the hypothesisthat such KAR hyper-activation may contribute to the death of nigralDA neurons, we investigated the effect of KAR antagonism on the DA neuron dysfunction and death that occur in the parkinQ311X mouse, a model of human parkin-induced toxicity. ResultsWe found that early accumulation of KARs occurs in the DA neurons of the parkinQ311X mouse model and that chronic administration of the KAR antagonist UBP310 prevents DA neuron loss. This neuroprotective effect was associated with rescue of the abnormal firing rate of nigral DA neurons and downregulation of GluK2, the key KAR subunit. ConclusionsThis study provides novel evidence ofa causal role of glutamate KARs in the DA neuron dysfunction and loss occurring in a mouse model of human parkin-induced toxicity. Our results support KAR as a potential target in the development of a neuroprotective therapy for ARJP.

scholarly journals NLRP3- and AIM2-autonomy in a mouse model of MSU crystal-induced acute inflammation in vivo suggests imiquimod-dependent targeting of Il-1[beta] expression as relevant therapy for gout patients.

2019 ◽  
Author(s):  
Alexandre Mariotte ◽  
Aurore Decauwer ◽  
Chrystelle Po ◽  
Cherine Abou-Faycal ◽  
Angelique Pichot ◽  
...  
Keyword(s):  
Mouse Model ◽  
Acute Inflammation ◽  
Joint Inflammation ◽  
Inflammatory Action ◽  
Recognition Receptor ◽  
Msu Crystals

The role of Monosodium Urate (MSU) crystals in gout pathophysiology is well described, as is the major impact of IL-1b in the inflammatory reaction that constitutes the hallmark of the disease. However, despite the discovery of the NLRP3 inflammasome and its role as a Pattern Recognition Receptor linking the detection of a danger signal (MSU) to IL-1b; secretion in vitro, the precise mechanisms leading to joint inflammation in gout patients are still poorly understood. Here, we provide an extensive clinical, biological and molecular characterization of the acute uratic inflammation mouse model induced by subcutaneous injection of MSU crystals, which accurately mimics human gout. Our work reveals several key features of MSU-dependent inflammation and identifies novel therapeutic opportunities, among which the use of topical application of imiquimod to promote interferon-dependent anti-inflammatory action maybe relevant.

Abstract P482: Elucidating And Characterizing The Molecular Mechanistic Role Of Phospholamban L39 Stop In The Pathophysiology Of Cardiomyopathy Using Patient-derived Human Induced Pluripotent Stem Cells And Humanized Knock-in Mouse Model Systems

2021 ◽  
Vol 129 (Suppl_1) ◽  
Author(s):  
Anichavezhi Devendran ◽  
Rasheed Bailey ◽  
Sumanta Kar ◽  
Francesca Stillitano ◽  
Irene Turnbull ◽  
...  
Keyword(s):  
Stem Cells ◽  
Mouse Model ◽  
Mononuclear Cells ◽  
Embryonic Stem ◽  
Model Systems ◽  
Patient Specific ◽  
Induced Pluripotent

Background: Heart failure (HF) is a complex clinical condition associated with substantial morbidity and mortality worldwide. The contractile dysfunction and arrhythmogenesis related to HF has been linked to the remodelling of calcium (Ca ++ ) handling. Phospholamban (PLN) has emerged as a key regulator of intracellular Ca ++ concentration. Of the PLN mutations, L39X is intriguing as it has not been fully characterized. This mutation is believed to be functionally equivalent to PLN null (KO) but contrary to PLN KO mice, L39X carriers develop a lethal cardiomyopathy (CMP). Our study aims at using induced pluripotent stem cell (iPSC)-derived cardiomyocytes (CMs) from homozygous L39X carriers to elucidate the role of L39X in human pathophysiology. Our plan also involves the characterization of humanized L39X knock-in mice (KM), which we hypothesize will develop a CMP from mis-localization of PLN and disruption of Ca ++ signalling. Methodology and Results: Mononuclear cells from Hom L39X carriers were obtained to generate 11 integration-free patient-specific iPSC clones. The iPSC-CMs were derived using established protocols. Compared to the WT iPSC-CMs, the Hom L39X derived-CMs PLN had an abnormal cytoplasmic distribution and formed intracellular aggregates, with the loss of perinuclear localization. There was also a 70% and 50% reduction of mRNA and protein expression of PLN respectively in L39X compared to WT iPSC-CMs. These findings indicated that L39X PLN is both under-expressed and mis-localized within the cell. To validate this observation in-vivo, we genetically modified FVB mice to harbour the human L39X. Following electroporation, positively transfected mouse embryonic stem cells were injected into host blastocysts to make humanized KM that were subsequently used to generate either a protamine-Cre (endogenous PLN driven expression) or a cardiac TNT mouse (i.e., CMP specific). Conclusion: Our data confirm an abnormal intracellular distribution of PLN, with the loss of perinuclear accumulation and mis-localization, suggestive of ineffective targeting to or retention of L39X. The mouse model will be critically important to validate the in-vitro observations and provides an ideal platform for future studies centred on the development of novel therapeutic strategies including virally delivered CRISPR/Cas9 for in-vivo gene editing and testing of biochemical signalling pathways.

scholarly journals Bmh1p (14-3-3) mediates pathways associated with virulence in Candida albicans

Microbiology ◽  
2009 ◽  
Vol 155 (5) ◽  
pp. 1536-1546 ◽  
Author(s):  
Michelle N. Kelly ◽  
Douglas A. Johnston ◽  
Bethany A. Peel ◽  
Timothy W. Morgan ◽  
Glen E. Palmer ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Mouse Model ◽  
Virulence Factors ◽  
Environmental Changes ◽  
Pathogenic Fungus ◽  
Binding Pocket ◽  
Lag Phase ◽  
Models Of Disease

The ability of the pathogenic fungus Candida albicans to cause disease requires rapid adaptation to changes in the host environment and to an evolving host immune response. The identification of ‘virulence factors’ using in vitro characterization of mutant strains has traditionally relied on a common set of phenotypic and biochemical assays (most often performed at 30 °C) and the subsequent correlation with their corresponding virulence in mouse models of disease. Utilizing a panel of isogenic mutants for the multifunctional signal-modulating 14-3-3 protein (Bmh1p), we have found that specific mutations affect a variety of different pathways currently associated with virulence, including those involved with the formation of filaments, as well as interaction with host immune cells. Surprisingly, our studies revealed that deficiencies in many of these pathways do not always correlate with virulence in a mouse model of disseminated infection. Mutations within the binding pocket of Bmh1p that affect the ability of the protein to efficiently bind ligand had varying effects on the results of a number of in vitro and in vivo assays. The capability, in vitro, to filament in embedment conditions, and to filament and form chlamydospores under microaerophilic conditions on cornmeal agar, does not correlate with virulence. It is likely that only a subset of hyphal signalling pathways is actually required for the establishment of infection in the disseminated mouse model. Most importantly, our results suggest that the delayed onset of lag-phase growth in vitro at 37 °C, and not at 30 °C, results in an inability of these mutants to rapidly adjust to environmental changes in vivo and may be responsible for their increased clearance and reduced virulence. It is critical, therefore, that future in vitro studies of putative virulence factors in C. albicans include careful characterization at physiological temperatures.

scholarly journals Strain-Specific Regulatory Role of Eukaryote-Like Serine/Threonine Phosphatase in Pneumococcal Adherence

2012 ◽  
Vol 80 (4) ◽  
pp. 1361-1372 ◽  
Author(s):  
Shivangi Agarwal ◽  
Shivani Agarwal ◽  
Preeti Pancholi ◽  
Vijay Pancholi
Keyword(s):  
High Efficiency ◽  
Regulatory System ◽  
Gene Encoding ◽  
Content Type ◽  
Knockout Mutants ◽  
Catalytically Active

ABSTRACTStreptococcus pneumoniaeexploits a battery of virulence factors to colonize the host. Although the eukaryote-like Ser/Thr kinase ofS. pneumoniae(StkP) has been implicated in physiology and virulence, the role of its cotranscribing phosphatase (PhpP) has remained elusive. The construction of nonpolar markerlessphpPknockout mutants (ΔphpP) in two pathogenic strains, D39 (type 2) and 6A-EF3114 (type 6A), indicated that PhpP is not indispensable for pneumococcal survival. Further, PhpP also participates in the regulation of cell wall biosynthesis/division, adherence, and biofilm formation in a strain-specific manner. Additionally, we provide hitherto-unknownin vitroandin vivoevidence of a physiologically relevant biochemical link between the StkP/PhpP-mediated cognate regulation and the two-component regulatory system TCS06 (RR06/HK06) that regulates the expression of the gene encoding an important pneumococcal surface adhesin, CbpA, which was found to be significantly upregulated in ΔphpPmutants. In particular, StkP (threonine)-phosphorylated RR06 bound to thecbpApromoter with high efficiency even in the absence of the HK06-responsive and catalytically active aspartate 51 residue. Together, our findings unravel the significant contributions of PhpP in pneumococcal physiology and adherence.

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