Potential Role of Phospholipases in Virulence and Fungal Pathogenesis

SUMMARY Microbial pathogens use a number of genetic strategies to invade the host and cause infection. These common themes are found throughout microbial systems. Secretion of enzymes, such as phospholipase, has been proposed as one of these themes that are used by bacteria, parasites, and pathogenic fungi. The role of extracellular phospholipase as a potential virulence factor in pathogenic fungi, including Candida albicans, Cryptococcus neoformans, and Aspergillus, has gained credence recently. In this review, data implicating phospholipase as a virulence factor in C. albicans, Candida glabrata, C. neoformans, and A. fumigatus are presented. A detailed description of the molecular and biochemical approaches used to more definitively delineate the role of phospholipase in the virulence of C. albicans is also covered. These approaches resulted in cloning of three genes encoding candidal phospholipases (caPLP1, caPLB2, and PLD). By using targeted gene disruption, C. albicans null mutants that failed to secrete phospholipase B, encoded by caPLB1, were constructed. When these isogenic strain pairs were tested in two clinically relevant murine models of candidiasis, deletion of caPLB1 was shown to lead to attenuation of candidal virulence. Importantly, immunogold electron microscopy studies showed that C. albicans secretes this enzyme during the infectious process. These data indicate that phospholipase B is essential for candidal virulence. Although the mechanism(s) through which phospholipase modulates fungal virulence is still under investigations, early data suggest that direct host cell damage and lysis are the main mechanisms contributing to fungal virulence. Since the importance of phospholipases in fungal virulence is already known, the next challenge will be to utilize these lytic enzymes as therapeutic and diagnostic targets.

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Induction of Fusarium lytic Enzymes by Extracts from Resistant and Susceptible Cultivars of Pea (Pisum sativum L.)

Pathogens ◽

10.3390/pathogens9110976 ◽

2020 ◽

Vol 9 (11) ◽

pp. 976

Author(s):

Lakshmipriya Perincherry ◽

Chaima Ajmi ◽

Souheib Oueslati ◽

Agnieszka Waśkiewicz ◽

Łukasz Stępień

Keyword(s):

Cell Wall ◽

Plant Extracts ◽

Plant Cell Wall ◽

Pathogenic Fungi ◽

Human Beings ◽

Cell Wall Degrading Enzymes ◽

Lytic Enzymes ◽

Mycelium Growth ◽

Oat Bran

Being pathogenic fungi, Fusarium produce various extracellular cell wall-degrading enzymes (CWDEs) that degrade the polysaccharides in the plant cell wall. They also produce mycotoxins that contaminate grains, thereby posing a serious threat to animals and human beings. Exposure to mycotoxins occurs through ingestion of contaminated grains, inhalation and through skin absorption, thereby causing mycotoxicoses. The toxins weaken the host plant, allowing the pathogen to invade successfully, with the efficiency varying from strain to strain and depending on the plant infected. Fusariumoxysporum predominantly produces moniliformin and cyclodepsipeptides, whereas F. proliferatum produces fumonisins. The aim of the study was to understand the role of various substrates and pea plant extracts in inducing the production of CWDEs and mycotoxins. Additionally, to monitor the differences in their levels when susceptible and resistant pea plant extracts were supplemented. The cultures of F. proliferatum and F. oxysporum strains were supplemented with various potential inducers of CWDEs. During the initial days after the addition of substrates, the fungus cocultivated with pea extracts and other carbon substrates showed increased activities of β-glucosidase, xylanase, exo-1,4-glucanase and lipase. The highest inhibition of mycelium growth (57%) was found in the cultures of F. proliferatum strain PEA1 upon the addition of cv. Sokolik extract. The lowest fumonisin content was exhibited by the cultures with the pea extracts and oat bran added, and this can be related to the secondary metabolites and antioxidants present in these substrates.

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Comparative Genomics and the Evolution of Pathogenicity in Human Pathogenic Fungi

Eukaryotic Cell ◽

10.1128/ec.00242-10 ◽

2010 ◽

Vol 10 (1) ◽

pp. 34-42 ◽

Cited By ~ 72

Author(s):

Gary P. Moran ◽

David C. Coleman ◽

Derek J. Sullivan

Keyword(s):

Fungal Pathogens ◽

Direct Interaction ◽

Pathogenic Fungi ◽

Gene Families ◽

Fungal Pathogenesis ◽

Individual Species ◽

Fungal Virulence ◽

Content Type ◽

Sequencing Technologies ◽

Genes Encoding

ABSTRACTBecause most fungi have evolved to be free-living in the environment and because the infections they cause are usually opportunistic in nature, it is often difficult to identify specific traits that contribute to fungal pathogenesis. In recent years, there has been a surge in the number of sequenced genomes of human fungal pathogens, and comparison of these sequences has proved to be an excellent resource for exploring commonalities and differences in how these species interact with their hosts. In order to survive in the human body, fungi must be able to adapt to new nutrient sources and environmental stresses. Therefore, genes involved in carbohydrate and amino acid metabolism and transport and genes encoding secondary metabolites tend to be overrepresented in pathogenic species (e.g.,Aspergillus fumigatus). However, it is clear that human commensal yeast species such asCandida albicanshave also evolved a range of specific factors that facilitate direct interaction with host tissues. The evolution of virulence across the human pathogenic fungi has occurred largely through very similar mechanisms. One of the most important mechanisms is gene duplication and the expansion of gene families, particularly in subtelomeric regions. Unlike the case for prokaryotic pathogens, horizontal transfer of genes between species and other genera does not seem to have played a significant role in the evolution of fungal virulence. New sequencing technologies promise the prospect of even greater numbers of genome sequences, facilitating the sequencing of multiple genomes and transcriptomes within individual species, and will undoubtedly contribute to a deeper insight into fungal pathogenesis.

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Characterization of the Role of a Non-GPCR Membrane-Bound CFEM Protein in the Pathogenicity and Germination of Botrytis cinerea

Microorganisms ◽

10.3390/microorganisms8071043 ◽

2020 ◽

Vol 8 (7) ◽

pp. 1043

Author(s):

Gulab Chand Arya ◽

Dhruv Aditya Srivastava ◽

Eswari P. J. Pandaranayaka ◽

Ekaterina Manasherova ◽

Dov Bernard Prusky ◽

...

Keyword(s):

Botrytis Cinerea ◽

Pathogenic Fungi ◽

Phytopathogenic Fungi ◽

Fungal Virulence ◽

Wide Range ◽

Membrane Bound ◽

The Common ◽

G Protein Coupled

The necrotrophic fungus Botrytis cinerea, is considered a major cause of postharvest losses in a wide range of crops. The common fungal extracellular membrane protein (CFEM), containing a conserved eight-cysteine pattern, was found exclusively in fungi. Previous studies in phytopathogenic fungi have demonstrated the role of membrane-bound and secreted CFEM-containing proteins in different aspects of fungal virulence. However, non-G protein-coupled receptor (non-GPCR) membrane CFEM proteins have not been studied yet in phytopathogenic fungi. In the present study, we have identified a non-GPCR membrane-bound CFEM-containing protein, Bcin07g03260, in the B. cinerea genome, and generated deletion mutants, ΔCFEM-Bcin07g03260, to study its potential role in physiology and virulence. Three independent ΔCFEM-Bcin07g03260 mutants showed significantly reduced progression of a necrotic lesion on tomato (Solanum lycopersicum) leaves. Further analysis of the mutants revealed significant reduction (approximately 20–30%) in conidial germination and consequent germ tube elongation compared with the WT. Our data complements a previous study of secreted ΔCFEM1 mutants of B. cinerea that showed reduced progression of necrotic lesions on leaves, without effect on germination. Considering various functions identified for CFEM proteins in fungal virulence, our work illustrates a potential new role for a non-GPCR membrane CFEM in pathogenic fungi to control virulence in the fungus B. cinerea.

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Human Nitric Oxide Synthase—Its Functions, Polymorphisms, and Inhibitors in the Context of Inflammation, Diabetes and Cardiovascular Diseases

International Journal of Molecular Sciences ◽

10.3390/ijms22010056 ◽

2020 ◽

Vol 22 (1) ◽

pp. 56

Author(s):

Magdalena Król ◽

Marta Kepinska

Keyword(s):

Nitric Oxide ◽

Free Radicals ◽

Nitric Oxide Synthase ◽

Cell Damage ◽

Intercellular Signaling ◽

Nos Inhibitors ◽

Genes Encoding ◽

Oxide Synthase ◽

Nos Isoforms

In various diseases, there is an increased production of the free radicals needed to carry out certain physiological processes but their excessive amounts can cause oxidative stress and cell damage. Enzymes play a major role in the transformations associated with free radicals. One of them is nitric oxide synthase (NOS), which catalyzes the formation of nitric oxide (NO). This enzyme exists in three forms (NOS1, NOS2, NOS3), each encoded by a different gene. The following work presents the most important information on the NOS isoforms and their role in the human body, including NO synthesis in various tissues and cells, intercellular signaling and activities supporting the immune system and regulating blood vessel functions. The role of NOS in pathological conditions such as obesity, diabetes and heart disease is considered. Attention is also paid to the influence of the polymorphisms of these genes, encoding particular isoforms, on the development of these pathologies and the role of NOS inhibitors in the treatment of patients.

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pH Signaling in Human Fungal Pathogens: a New Target for Antifungal Strategies

Eukaryotic Cell ◽

10.1128/ec.00313-13 ◽

2014 ◽

Vol 13 (3) ◽

pp. 342-352 ◽

Cited By ~ 49

Author(s):

Muriel Cornet ◽

Claude Gaillardin

Keyword(s):

Mammalian Cells ◽

Drug Targets ◽

Fungal Pathogens ◽

Synergistic Effects ◽

Pathogenic Fungi ◽

Antifungal Drugs ◽

Drug Pressure ◽

Fungal Virulence ◽

Content Type

ABSTRACTFungi are exposed to broadly fluctuating environmental conditions, to which adaptation is crucial for their survival. An ability to respond to a wide pH range, in particular, allows them to cope with rapid changes in their extracellular settings. PacC/Rim signaling elicits the primary pH response in both model and pathogenic fungi and has been studied in multiple fungal species. In the predominant human pathogenic fungi, namely,Candida albicans,Aspergillus fumigatus, andCryptococcus neoformans, this pathway is required for many functions associated with pathogenesis and virulence. Aspects of this pathway are fungus specific and do not exist in mammalian cells. In this review, we highlight recent advances in our understanding of PacC/Rim-mediated functions and discuss the growing interest in this cascade and its factors as potential drug targets for antifungal strategies. We focus on both conserved and distinctive features in model and pathogenic fungi, highlighting the specificities of PacC/Rim signaling inC. albicans,A. fumigatus, andC. neoformans. We consider the role of this pathway in fungal virulence, including modulation of the host immune response. Finally, as now recognized for other signaling cascades, we highlight the role of pH in adaptation to antifungal drug pressure. By acting on the PacC/Rim pathway, it may therefore be possible (i) to ensure fungal specificity and to limit the side effects of drugs, (ii) to ensure broad-spectrum efficacy, (iii) to attenuate fungal virulence, (iv) to obtain additive or synergistic effects with existing antifungal drugs through tolerance inhibition, and (v) to slow the emergence of resistant mutants.

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DNA methylation in satellite repeats disorders

Essays in Biochemistry ◽

10.1042/ebc20190028 ◽

2019 ◽

Vol 63 (6) ◽

pp. 757-771 ◽

Cited By ~ 4

Author(s):

Claire Francastel ◽

Frédérique Magdinier

Keyword(s):

Dna Methylation ◽

Human Genome ◽

Repetitive Dna ◽

Dna Sequences ◽

Satellite Repeats ◽

Tremendous Progress ◽

Genes Encoding ◽

Dna Elements ◽

Near Future

Abstract Despite the tremendous progress made in recent years in assembling the human genome, tandemly repeated DNA elements remain poorly characterized. These sequences account for the vast majority of methylated sites in the human genome and their methylated state is necessary for this repetitive DNA to function properly and to maintain genome integrity. Furthermore, recent advances highlight the emerging role of these sequences in regulating the functions of the human genome and its variability during evolution, among individuals, or in disease susceptibility. In addition, a number of inherited rare diseases are directly linked to the alteration of some of these repetitive DNA sequences, either through changes in the organization or size of the tandem repeat arrays or through mutations in genes encoding chromatin modifiers involved in the epigenetic regulation of these elements. Although largely overlooked so far in the functional annotation of the human genome, satellite elements play key roles in its architectural and topological organization. This includes functions as boundary elements delimitating functional domains or assembly of repressive nuclear compartments, with local or distal impact on gene expression. Thus, the consideration of satellite repeats organization and their associated epigenetic landmarks, including DNA methylation (DNAme), will become unavoidable in the near future to fully decipher human phenotypes and associated diseases.

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MicroRNAs in Noise-Induced Hearing Loss and their Regulation by Oxidative Stress and Inflammation

Current Drug Targets ◽

10.2174/1389450121666200615145552 ◽

2020 ◽

Vol 21 (12) ◽

pp. 1216-1224

Author(s):

Fatemeh Forouzanfar ◽

Samira Asgharzade

Keyword(s):

Oxidative Stress ◽

Hearing Loss ◽

Hair Cell ◽

Noise Exposure ◽

Cell Damage ◽

Sensory Cells ◽

Noise Induced Hearing Loss ◽

Irreversible Damage ◽

Open Access Journals

Noise exposure (NE) has been recognized as one of the causes of sensorineural hearing loss (SNHL), which can bring about irreversible damage to sensory hair cells in the cochlea, through the launch of oxidative stress pathways and inflammation. Accordingly, determining the molecular mechanism involved in regulating hair cell apoptosis via NE is essential to prevent hair cell damage. However, the role of microRNAs (miRNAs) in the degeneration of sensory cells of the cochlea during NE has not been so far uncovered. Thus, the main purpose of this study was to demonstrate the regulatory role of miRNAs in the oxidative stress pathway and inflammation induced by NE. In this respect, articles related to noise-induced hearing loss (NIHL), oxidative stress, inflammation, and miRNA from various databases of Directory of Open Access Journals (DOAJ), Google Scholar, PubMed; Library, Information Science & Technology Abstracts (LISTA), and Web of Science were searched and retrieved. The findings revealed that several studies had suggested that up-regulation of miR-1229-5p, miR-451a, 185-5p, 186 and down-regulation of miRNA-96/182/183 and miR-30b were involved in oxidative stress and inflammation which could be used as biomarkers for NIHL. There was also a close relationship between NIHL and miRNAs, but further research is required to prove a causal association between miRNA alterations and NE, and also to determine miRNAs as biomarkers indicating responses to NE.

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The Signaling Pathways in Nitric Oxide Production by Neutrophils Exposed to N-nitrosodimethylamine

Letters in Drug Design & Discovery ◽

10.2174/1570180815666180426121503 ◽

2018 ◽

Vol 16 (2) ◽

pp. 194-199

Author(s):

Wioletta Ratajczak-Wrona ◽

Ewa Jablonska

Keyword(s):

Nitric Oxide ◽

Signaling Pathways ◽

Molecular Mechanisms ◽

Polymorphonuclear Neutrophils ◽

Microbial Pathogens ◽

Human Neutrophils ◽

No Production ◽

Oxide Synthase ◽

Inducible Nitric Oxide

Background: Polymorphonuclear neutrophils (PMNs) play a crucial role in the innate immune system’s response to microbial pathogens through the release of reactive nitrogen species, including Nitric Oxide (NO). </P><P> Methods: In neutrophils, NO is produced by the inducible Nitric Oxide Synthase (iNOS), which is regulated by various signaling pathways and transcription factors. N-nitrosodimethylamine (NDMA), a potential human carcinogen, affects immune cells. NDMA plays a major part in the growing incidence of cancers. Thanks to the increasing knowledge on the toxicological role of NDMA, the environmental factors that condition the exposure to this compound, especially its precursors- nitrates arouse wide concern. Results: In this article, we present a detailed summary of the molecular mechanisms of NDMA’s effect on the iNOS-dependent NO production in human neutrophils. Conclusion: This research contributes to a more complete understanding of the mechanisms that explain the changes that occur during nonspecific cellular responses to NDMA toxicity.

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Flavonoids: Potential Candidates for the Treatment of Neurodegenerative Disorders

Biomedicines ◽

10.3390/biomedicines9020099 ◽

2021 ◽

Vol 9 (2) ◽

pp. 99

Author(s):

Shweta Devi ◽

Vijay Kumar ◽

Sandeep Kumar Singh ◽

Ashish Kant Dubey ◽

Jong-Joo Kim

Keyword(s):

Stress Response ◽

Stress Responses ◽

Neurodegenerative Disorders ◽

Cell Damage ◽

Cellular Stress ◽

Clinical Manifestations ◽

Cellular Stress Response ◽

Dramatic Rise ◽

Cellular Stress Responses

Neurodegenerative disorders, such as Parkinson’s disease (PD), Alzheimer’s disease (AD), Amyotrophic lateral sclerosis (ALS), and Huntington’s disease (HD), are the most concerning disorders due to the lack of effective therapy and dramatic rise in affected cases. Although these disorders have diverse clinical manifestations, they all share a common cellular stress response. These cellular stress responses including neuroinflammation, oxidative stress, proteotoxicity, and endoplasmic reticulum (ER)-stress, which combats with stress conditions. Environmental stress/toxicity weakened the cellular stress response which results in cell damage. Small molecules, such as flavonoids, could reduce cellular stress and have gained much attention in recent years. Evidence has shown the potential use of flavonoids in several ways, such as antioxidants, anti-inflammatory, and anti-apoptotic, yet their mechanism is still elusive. This review provides an insight into the potential role of flavonoids against cellular stress response that prevent the pathogenesis of neurodegenerative disorders.

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A novel putative microtubule-associated protein is involved in arbuscule development during arbuscular mycorrhiza formation

Plant and Cell Physiology ◽

10.1093/pcp/pcaa159 ◽

2021 ◽

Author(s):

Tania Ho-Plágaro ◽

Raúl Huertas ◽

María I Tamayo-Navarrete ◽

Elison Blancaflor ◽

Nuria Gavara ◽

...

Keyword(s):

Plant Root ◽

Arbuscular Mycorrhizal ◽

Host Cells ◽

Root Cells ◽

Filament Dynamics ◽

Fungal Structure ◽

Genes Encoding ◽

Associated Proteins ◽

Mycorrhizal Development

Abstract The formation of arbuscular mycorrhizal (AM) symbiosis requires plant root host cells to undergo major structural and functional reprogramming in order to house the highly branched AM fungal structure for the reciprocal exchange of nutrients. These morphological modifications are associated with cytoskeleton remodelling. However, molecular bases and the role of microtubules (MTs) and actin filament dynamics during AM formation are largely unknown. In this study, the tomato tsb gene, belonging to a Solanaceae group of genes encoding MT-associated proteins for pollen development, was found to be highly expressed in root cells containing arbuscules. At earlier stages of mycorrhizal development, tsb overexpression enhanced the formation of highly developed and transcriptionally active arbuscules, while tsb silencing hampers the formation of mature arbuscules and represses arbuscule functionality. However, at later stages of mycorrhizal colonization, tsb OE roots accumulate fully developed transcriptionally inactive arbuscules, suggesting that the collapse and turnover of arbuscules might be impaired by TSB accumulation. Imaging analysis of the MT cytoskeleton in cortex root cells overexpressing tsb revealed that TSB is involved in MT-bundling. Taken together, our results provide unprecedented insights into the role of novel MT-associated protein in MT rearrangements throughout the different stages of the arbuscule life cycle.

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