scholarly journals Pleiotropic Effects of the P5-Type ATPase SpfA on Stress Response Networks Contribute to Virulence in the Pathogenic Mold Aspergillus fumigatus

mBio ◽  
2021 ◽  
Author(s):  
José P. Guirao-Abad ◽  
Martin Weichert ◽  
Ginés Luengo-Gil ◽  
Sarah Sze Wah Wong ◽  
Vishukumar Aimanianda ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Stress Resistance ◽  
Secretory Pathway ◽  
Pathogenic Fungi ◽  
Antifungal Drugs ◽  
Gene Encoding ◽  
Content Type ◽  
Downstream Target ◽  
P Type ◽  
Er Homeostasis

The fungal UPR is an adaptive signaling pathway in the ER that buffers fluctuations in ER stress but also serves as a virulence regulatory hub in species of pathogenic fungi that rely on secretory pathway homeostasis for pathogenicity. This study demonstrates that the gene encoding the ER-localized P5-type ATPase SpfA is a downstream target of the UPR in the pathogenic mold A. fumigatus and that it works together with a second ER-localized P-type ATPase, SrcA, to support ER homeostasis, oxidative stress resistance, susceptibility to antifungal drugs, and virulence of A. fumigatus .

scholarly journals Dysfunction of Prohibitin 2 Results in Reduced Susceptibility to Multiple Antifungal Drugs via Activation of the Oxidative Stress-Responsive Transcription Factor Pap1 in Fission Yeast

2018 ◽  
Vol 62 (11) ◽  
Author(s):  
Qiannan Liu ◽  
Fan Yao ◽  
Guanglie Jiang ◽  
Min Xu ◽  
Si Chen ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Drug Resistance ◽  
Transcription Factor ◽  
Fission Yeast ◽  
Mitochondrial Protein ◽  
Antifungal Drugs ◽  
Antifungal Drug ◽  
Gene Encoding ◽  
Content Type ◽  
Antifungal Drug Resistance

ABSTRACT The fight against resistance to antifungal drugs requires a better understanding of the underlying cellular mechanisms. In order to gain insight into the mechanisms leading to antifungal drug resistance, we performed a genetic screen on a model organism, Schizosaccharomyces pombe, to identify genes whose overexpression caused resistance to antifungal drugs, including clotrimazole and terbinafine. We identified the phb2+ gene, encoding a highly conserved mitochondrial protein, prohibitin (Phb2), as a novel determinant of reduced susceptibility to multiple antifungal drugs. Unexpectedly, deletion of the phb2+ gene also exhibited antifungal drug resistance. Overexpression of the phb2+ gene failed to cause drug resistance when the pap1+ gene, encoding an oxidative stress-responsive transcription factor, was deleted. Furthermore, pap1+ mRNA expression was significantly increased when the phb2+ gene was overexpressed or deleted. Importantly, either overexpression or deletion of the phb2+ gene stimulated the synthesis of NO and reactive oxygen species (ROS), as measured by the cell-permeant fluorescent NO probe DAF-FM DA (4-amino-5-methylamino-2′,7′-difluorofluorescein diacetate) and the ROS probe DCFH-DA (2′,7′-dichlorodihydrofluorescein diacetate), respectively. Taken together, these results suggest that Phb2 dysfunction results in reduced susceptibility to multiple antifungal drugs by increasing NO and ROS synthesis due to dysfunctional mitochondria, thereby activating the transcription factor Pap1 in fission yeast.

scholarly journals Two Distinctly Localized P-Type ATPases Collaborate to Maintain Organelle Homeostasis Required for Glycoprotein Processing and Quality Control

2002 ◽  
Vol 13 (11) ◽  
pp. 3955-3966 ◽  
Author(s):  
Shilpa Vashist ◽  
Christian G. Frank ◽  
Claude A. Jakob ◽  
Davis T.W. Ng
Keyword(s):  
Quality Control ◽  
Unfolded Protein Response ◽  
Secretory Pathway ◽  
Ion Homeostasis ◽  
Unfolded Protein ◽  
The Unfolded Protein Response ◽  
Coa Reductase ◽  
Protein Response ◽  
P Type ◽  
Er Homeostasis

Membrane transporter proteins are essential for the maintenance of cellular ion homeostasis. In the secretory pathway, the P-type ATPase family of transporters is found in every compartment and the plasma membrane. Here, we report the identification of COD1/SPF1(control of HMG-CoA reductase degradation/SPF1) through genetic strategies intended to uncover genes involved in protein maturation and endoplasmic reticulum (ER)-associated degradation (ERAD), a quality control pathway that rids misfolded proteins. Cod1p is a putative ER P-type ATPase whose expression is regulated by the unfolded protein response, a stress-inducible pathway used to monitor and maintain ER homeostasis. COD1 mutants activate the unfolded protein response and are defective in a variety of functions apart from ERAD, which further support a homeostatic role.COD1 mutants display phenotypes similar to strains lacking Pmr1p, a Ca2+/Mn2+pump that resides in the medial-Golgi. Because of its localization, the previously reported role of PMR1 in ERAD was somewhat enigmatic. A clue to their respective roles came from observations that the two genes are not generally required for ERAD. We show that the specificity is rooted in a requirement for both genes in protein-linked oligosaccharide trimming, a requisite ER modification in the degradation of some misfolded glycoproteins. Furthermore, Cod1p, like Pmr1p, is also needed for the outer chain modification of carbohydrates in the Golgi apparatus despite its ER localization. In strains deleted of both genes, these activities are nearly abolished. The presence of either protein alone, however, can support partial function for both compartments. Taken together, our results reveal an interdependent relationship between two P-type ATPases to maintain homeostasis of the organelles where they reside.

scholarly journals Deletion ofADA2Increases Antifungal Drug Susceptibility and Virulence inCandida glabrata

2018 ◽  
Vol 62 (3) ◽  
Author(s):  
Shang-Jie Yu ◽  
Ya-Lin Chang ◽  
Ying-Lien Chen
Keyword(s):  
Cell Wall ◽  
Systemic Infection ◽  
Drug Tolerance ◽  
Drug Susceptibility ◽  
Antifungal Drugs ◽  
Antifungal Drug ◽  
Saga Complex ◽  
Necrosis Factor Alpha ◽  
Content Type ◽  
Downstream Target

ABSTRACTCandida glabrata, the second most frequent cause of candidiasis afterCandida albicans, is an emerging human fungal pathogen that is intrinsically drug tolerant. Currently, studies ofC. glabratagenes involved in drug tolerance are limited. Ada2, a component serving as a transcription adaptor of the Spt-Ada-Gcn5 acetyltransferase (SAGA) complex, is required for antifungal drug tolerance and virulence inC. albicans. However, its roles inC. glabrataremain elusive. In this study, we found thatada2mutants demonstrated severe growth defects at 40°C but only mild defects at 37°C or 25°C. In addition,C. glabrata ada2mutants exhibited pleiotropic phenotypes, including susceptibility to three classes of antifungal drugs (i.e., azoles, echinocandins, and polyenes) and cell wall-perturbing agents but resistance to the endoplasmic reticulum stressor tunicamycin. According to RNA sequence analysis, the expression of 43 genes was downregulated and the expression of 442 genes was upregulated in theada2mutant compared to their expression in the wild type.C. glabrata ADA2, along with its downstream targetERG6, controls antifungal drug tolerance and cell wall integrity. Surprisingly,ada2mutants were hypervirulent in a murine model of systemic infection, possibly due to the upregulation of multiple adhesin-like genes, increased agar invasion, and overstimulation of murine tumor necrosis factor alpha production.

scholarly journals Disruption of the Phospholipase D Gene Attenuates the Virulence of Aspergillus fumigatus

2011 ◽  
Vol 80 (1) ◽  
pp. 429-440 ◽  
Author(s):  
Xianping Li ◽  
Meihua Gao ◽  
Xuelin Han ◽  
Sha Tao ◽  
Dongyu Zheng ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Aspergillus Fumigatus ◽  
Phospholipase D ◽  
Morphological Characteristics ◽  
Pathogenic Fungi ◽  
Lung Epithelial Cells ◽  
Gene Encoding ◽  
Content Type ◽  
Important Virulence Factor ◽  
The Impact

ABSTRACTAspergillus fumigatusis the most prevalent airborne fungal pathogen that induces serious infections in immunocompromised patients. Phospholipases are key enzymes in pathogenic fungi that cleave host phospholipids, resulting in membrane destabilization and host cell penetration. However, knowledge of the impact of phospholipases onA. fumigatusvirulence is rather limited. In this study, disruption of thepldgene encoding phospholipase D (PLD), an important member of the phospholipase protein family inA. fumigatus, was confirmed to significantly decrease both intracellular and extracellular PLD activity ofA. fumigatus. Thepldgene disruption did not alter conidial morphological characteristics, germination, growth, and biofilm formation but significantly suppressed the internalization ofA. fumigatusinto A549 epithelial cells without affecting conidial adhesion to epithelial cells. Importantly, the suppressed internalization was fully rescued in the presence of 100 μM phosphatidic acid, the PLD product. Indeed, complementation ofpldrestored the PLD activity and internalization capacity ofA. fumigatus. Phagocytosis ofA. fumigatusconidia by J774 macrophages was not affected by the absence of thepldgene. Pretreatment of conidia with 1-butanol and a specific PLD inhibitor decreased the internalization ofA. fumigatusinto A549 epithelial cells but had no effect on phagocytosis by J774 macrophages. Finally, loss of thepldgene attenuated the virulence ofA. fumigatusin mice immunosuppressed with hydrocortisone acetate but not with cyclophosphamide. These data suggest that PLD ofA. fumigatusregulates its internalization into lung epithelial cells and may represent an important virulence factor forA. fumigatusinfection.

scholarly journals Identification of Plasmalogens in the Cytoplasmic Membrane of Bifidobacterium animalis subsp. lactis

2011 ◽  
Vol 78 (3) ◽  
pp. 880-884 ◽  
Author(s):  
Taylor S. Oberg ◽  
Robert E. Ward ◽  
James L. Steele ◽  
Jeff R. Broadbent
Keyword(s):  
Oxidative Stress ◽  
Environmental Stress ◽  
Stress Resistance ◽  
Cell Membranes ◽  
Cytoplasmic Membrane ◽  
Eukaryotic Cell ◽  
Bacterial Membrane ◽  
Membrane Composition ◽  
Content Type ◽  
Bifidobacterium Animalis

ABSTRACTPlasmalogens are ether-linked lipids that may influence oxidative stress resistance of eukaryotic cell membranes. Since bacterial membrane composition can influence environmental stress resistance, we explored the prevalence of plasmalogens in the cytoplasmic membrane ofBifidobacterium animalissubsp.lactis. Results showed plasmalogens are a major component of theB. animalissubsp.lactismembrane.

scholarly journals Proline Metabolism IncreaseskatGExpression and Oxidative Stress Resistance in Escherichia coli

2014 ◽  
Vol 197 (3) ◽  
pp. 431-440 ◽  
Author(s):  
Lu Zhang ◽  
James R. Alfano ◽  
Donald F. Becker
Keyword(s):  
Oxidative Stress ◽  
Escherichia Coli ◽  
Hydrogen Peroxide ◽  
Mutant Strain ◽  
Stress Resistance ◽  
Proline Metabolism ◽  
Wild Type ◽  
Content Type ◽  
Oxidative Stress Resistance ◽  
Proline Utilization

The oxidation ofl-proline to glutamate in Gram-negative bacteria is catalyzed by the proline utilization A (PutA) flavoenzyme, which contains proline dehydrogenase (PRODH) and Δ1-pyrroline-5-carboxylate (P5C) dehydrogenase domains in a single polypeptide. Previous studies have suggested that aside from providing energy, proline metabolism influences oxidative stress resistance in different organisms. To explore this potential role and the mechanism, we characterized the oxidative stress resistance of wild-type andputAmutant strains ofEscherichia coli. Initial stress assays revealed that theputAmutant strain was significantly more sensitive to oxidative stress than the parental wild-type strain. Expression of PutA in theputAmutant strain restored oxidative stress resistance, confirming that depletion of PutA was responsible for the oxidative stress phenotype. Treatment of wild-type cells with proline significantly increased hydroperoxidase I (encoded bykatG) expression and activity. Furthermore, the ΔkatGstrain failed to respond to proline, indicating a critical role for hydroperoxidase I in the mechanism of proline protection. The global regulator OxyR activates the expression ofkatGalong with several other genes involved in oxidative stress defense. In addition tokatG, proline increased the expression ofgrxA(glutaredoxin 1) andtrxC(thioredoxin 2) of the OxyR regulon, implicating OxyR in proline protection. Proline oxidative metabolism was shown to generate hydrogen peroxide, indicating that proline increases oxidative stress tolerance inE. colivia a preadaptive effect involving endogenous hydrogen peroxide production and enhanced catalase-peroxidase activity.

scholarly journals The Cch1-Mid1 High-Affinity Calcium Channel Contributes to the Virulence of Cryptococcus neoformans by Mitigating Oxidative Stress

2015 ◽  
Vol 14 (11) ◽  
pp. 1135-1143 ◽  
Author(s):  
Kiem Vu ◽  
Jennifer M. Bautos ◽  
Angie Gelli
Keyword(s):  
Oxidative Stress ◽  
Cryptococcus Neoformans ◽  
Defense Mechanisms ◽  
Pathogenic Fungi ◽  
Growth Defect ◽  
Compensatory Mechanism ◽  
General Role ◽  
Content Type ◽  
High Affinity ◽  
Oxidative Stresses

ABSTRACT Pathogenic fungi have developed mechanisms to cope with stresses imposed by hosts. For Cryptococcus spp., this implies active defense mechanisms that attenuate and ultimately overcome the onslaught of oxidative stresses in macrophages. Among cellular pathways within Cryptococcus neoformans ' arsenal is the plasma membrane high-affinity Cch1-Mid1 calcium (Ca 2+ ) channel (CMC). Here we show that CMC has an unexpectedly complex and disparate role in mitigating oxidative stress. Upon inhibiting the Ccp1-mediated oxidative response pathway with antimycin, strains of C. neoformans expressing only Mid1 displayed enhanced growth, but this was significantly attenuated upon H 2 O 2 exposure in the absence of Mid1, suggesting a regulatory role for Mid1 acting through the Ccp1-mediated oxidative stress response. This notion is further supported by the interaction detected between Mid1 and Ccp1 (cytochrome c peroxidase). In contrast, Cch1 appears to have a more general role in promoting cryptococci survival during oxidative stress. A strain lacking Cch1 displayed a growth defect in the presence of H 2 O 2 without BAPTA [(1,2-bis(2-aminophenoxy)ethane- N , N , N ′, N ′-tetraacetic acid, cesium salt] or additional stressors such as antimycin. Consistent with a greater contribution of Cch1 to oxidative stress tolerance, an intracellular growth defect was observed for the cch1 Δ strain in the macrophage cell line J774A.1. Interestingly, while the absence of either Mid1 or Cch1 significantly compromises the ability of C. neoformans to tolerate oxidative stress, the absence of both Mid1 and Cch1 has a negligible effect on C. neoformans growth during H 2 O 2 stress, suggesting the existence of a compensatory mechanism that becomes active in the absence of CMC.

scholarly journals Role of the Filifactor alocis Hypothetical Protein FA519 in Oxidative Stress Resistance

2021 ◽  
Author(s):  
Ezinne Aja ◽  
Arunima Mishra ◽  
Yuetan Dou ◽  
Hansel M. Fletcher
Keyword(s):  
Oxidative Stress ◽  
Periodontal Disease ◽  
Stress Resistance ◽  
Hypothetical Protein ◽  
Content Type ◽  
Genetic Tools ◽  
Oxidative Stress Resistance ◽  
Filifactor Alocis ◽  
Diagnostic Indicator

Filifactor alocis is an emerging member of the periodontal community and is now proposed to be a diagnostic indicator of periodontal disease. However, due to the lack of genetic tools available to study this organism, not much is known about its virulence attributes.

scholarly journals Farnesol Induces Hydrogen Peroxide Resistance in Candida albicans Yeast by Inhibiting the Ras-Cyclic AMP Signaling Pathway

2010 ◽  
Vol 9 (4) ◽  
pp. 569-577 ◽  
Author(s):  
Aurélie Deveau ◽  
Amy E. Piispanen ◽  
Angelyca A. Jackson ◽  
Deborah A. Hogan
Keyword(s):  
Oxidative Stress ◽  
Hydrogen Peroxide ◽  
Candida Albicans ◽  
Adenylate Cyclase ◽  
Signaling Pathway ◽  
Stress Resistance ◽  
Ros Generation ◽  
Signaling Molecule ◽  
Content Type ◽  
Oxidative Stress Resistance

ABSTRACT Farnesol, a Candida albicans cell-cell signaling molecule that participates in the control of morphology, has an additional role in protection of the fungus against oxidative stress. In this report, we show that although farnesol induces the accumulation of intracellular reactive oxygen species (ROS), ROS generation is not necessary for the induction of catalase (Cat1)-mediated oxidative-stress resistance. Two antioxidants, α-tocopherol and, to a lesser extent, ascorbic acid effectively reduced intracellular ROS generation by farnesol but did not alter farnesol-induced oxidative-stress resistance. Farnesol inhibits the Ras1-adenylate cyclase (Cyr1) signaling pathway to achieve its effects on morphology under hypha-inducing conditions, and we demonstrate that farnesol induces oxidative-stress resistance by a similar mechanism. Strains lacking either Ras1 or Cyr1 no longer exhibited increased protection against hydrogen peroxide upon preincubation with farnesol. While we also observed the previously reported increase in the phosphorylation level of Hog1, a known regulator of oxidative-stress resistance, in the presence of farnesol, the hog1/hog1 mutant did not differ from wild-type strains in terms of farnesol-induced oxidative-stress resistance. Analysis of Hog1 levels and its phosphorylation states in different mutant backgrounds indicated that mutation of the components of the Ras1-adenylate cyclase pathway was sufficient to cause an increase of Hog1 phosphorylation even in the absence of farnesol or other exogenous sources of oxidative stress. This finding indicates the presence of unknown links between these signaling pathways. Our results suggest that farnesol effects on the Ras-adenylate cyclase cascade are responsible for many of the observed activities of this fungal signaling molecule.

scholarly journals The BacterialiprAGene Is Conserved across Enterobacteriaceae, Is Involved in Oxidative Stress Resistance, and Influences Gene Expression in Salmonella enterica Serovar Typhimurium

2016 ◽  
Vol 198 (16) ◽  
pp. 2166-2179 ◽  
Author(s):  
Allison Herman ◽  
Jacquelyn Serfecz ◽  
Alexandra Kinnally ◽  
Kathleen Crosby ◽  
Matthew Youngman ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Amino Acids ◽  
Stress Resistance ◽  
Salmonella Enterica ◽  
Phosphotransferase System ◽  
Protein Activity ◽  
Altered Expression ◽  
Content Type ◽  
Oxidative Stress Resistance ◽  
Serovar Typhimurium

ABSTRACTTheiprAgene (formerly known asyaiVor STM0374) is located in a two-gene operon in theSalmonella entericaserovar Typhimurium genome and is associated with altered expression during spaceflight and rotating-wall-vessel culture conditions that increase virulence. However,iprAis uncharacterized in the literature. In this report, we present the first targeted characterization of this gene, which revealed thatiprAis highly conserved acrossEnterobacteriaceae. We found thatS. Typhimurium,Escherichia coli, andEnterobacter cloacaeΔiprAmutant strains display a multi-log-fold increase in oxidative stress resistance that is complemented using a plasmid-borne wild-type (WT) copy of theS. TyphimuriumiprAgene. This observation was also associated with increased catalase activity, increasedS. Typhimurium survival in macrophages, and partial dependence on thekatEgene and full dependence on therpoSgene. Our results indicate that IprA protein activity is sensitive to deletion of the N- and C-terminal 10 amino acids, while a region that includes amino acids 56 to 80 is dispensable for activity. RNA sequencing (RNA-Seq) analysis revealed several genes altered in expression in theS. Typhimurium ΔiprAmutant strain compared to the WT, including those involved in fimbria formation,spvABCD-mediated virulence, ethanolamine utilization, the phosphotransferase system (PTS) transport, and flagellin phase switching from FlgB to FliC (likely a stochastic event) and several genes of hypothetical or putative function.IMPORTANCEOverall, this work reveals that the conservediprAgene measurably influences bacterial biology and highlights the pool of currently uncharacterized genes that are conserved across bacterial genomes. These genes represent potentially useful targets for bacterial engineering, vaccine design, and other possible applications.

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