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1.
Int J Mol Sci ; 22(19)2021 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-34638975

RESUMO

Candida albicans is a commensal fungus of humans but can cause infections, particularly in immunocompromised individuals, ranging from superficial to life-threatening systemic infections. The cell wall is the outermost layer of C. albicans that interacts with the host environment. Moreover, antimicrobial peptides (AMPs) are important components in innate immunity and play crucial roles in host defense. Our previous studies showed that the human AMP LL-37 binds to the cell wall of C. albicans, alters the cell wall integrity (CWI) and affects cell adhesion of this pathogen. In this study, we aimed to further investigate the molecular mechanisms underlying the C. albicans response to LL-37. We found that LL-37 causes cell wall stress, activates unfolded protein response (UPR) signaling related to the endoplasmic reticulum (ER), induces ER-derived reactive oxygen species and affects protein secretion. Interestingly, the deletion of the SFP1 gene encoding a transcription factor reduced C. albicans susceptibility to LL-37, which is cell wall-associated. Moreover, in the presence of LL-37, deletion of SFP1 attenuated the UPR pathway, upregulated oxidative stress responsive (OSR) genes and affected bovine serum albumin (BSA) degradation by secreted proteases. Therefore, these findings suggested that Sfp1 positively regulates cell wall integrity and ER homeostasis upon treatment with LL-37 and shed light on pathogen-host interactions.


Assuntos
Peptídeos Catiônicos Antimicrobianos/farmacologia , Candida albicans/metabolismo , Parede Celular/metabolismo , Proteínas de Ligação a DNA/metabolismo , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Proteínas Fúngicas/metabolismo , Transdução de Sinais/efeitos dos fármacos , Candida albicans/efeitos dos fármacos , Candida albicans/genética , Parede Celular/efeitos dos fármacos , Proteínas de Ligação a DNA/genética , Retículo Endoplasmático/metabolismo , Estresse do Retículo Endoplasmático/genética , Proteínas Fúngicas/genética , Deleção de Genes , Homeostase/efeitos dos fármacos , Homeostase/genética , Interações Hospedeiro-Patógeno , Humanos , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/genética , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/genética , Resposta a Proteínas não Dobradas/efeitos dos fármacos , Resposta a Proteínas não Dobradas/genética , Regulação para Cima/efeitos dos fármacos , Regulação para Cima/genética , Catelicidinas
2.
FEMS Yeast Res ; 19(2)2019 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-30649293

RESUMO

Candida albicans is an important fungal pathogen in humans. Rhb1 is a small GTPase of the Ras superfamily and is conserved from yeasts to humans. In C. albicans, Rhb1 regulates the expression of secreted protease 2, low nitrogen-mediated morphogenesis, and biofilm formation. Moreover, our previous studies have indicated that Rhb1 is associated with the target of rapamycin (TOR) signaling pathway. In this study, we further explored the relationship between Rhb1 and drug susceptibility. The RHB1 deletion mutant exhibited reduced fluconazole susceptibility, and this phenotype occurred mainly through the increased gene expression and activity of efflux pumps. In addition, Mrr1 and Tac1 are transcription factors that can activate efflux pump gene expression. However, the RHB1 deletion, RHB1/MRR1 and RHB1/TAC1 double deletion mutants had no significant differences in efflux pump gene expression and fluconazole susceptibility, suggesting that Rhb1-regulated efflux pump genes do not act through Mrr1 and Tac1. We also showed that membrane localization is crucial for Rhb1 activity in response to fluconazole. Finally, Rhb1 was linked not only to the TOR but also to the Mkc1 mitogen-activated protein kinase signaling pathway in response to fluconazole. In sum, this study unveiled a new role of Rhb1 in the regulation of C. albicans drug susceptibility.


Assuntos
Antifúngicos/farmacologia , Candida albicans/efeitos dos fármacos , Fluconazol/farmacologia , Regulação Fúngica da Expressão Gênica , Proteínas Monoméricas de Ligação ao GTP/metabolismo , Transporte Biológico Ativo , Candida albicans/genética , Farmacorresistência Fúngica , Deleção de Genes , Proteínas de Membrana Transportadoras/metabolismo , Testes de Sensibilidade Microbiana , Proteínas Monoméricas de Ligação ao GTP/deficiência
3.
Mar Drugs ; 17(6)2019 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-31207891

RESUMO

More than 80% of infectious bacteria form biofilm, which is a bacterial cell community surrounded by secreted polysaccharides, proteins and glycolipids. Such bacterial superstructure increases resistance to antimicrobials and host defenses. Thus, to control these biofilm-forming pathogenic bacteria requires antimicrobial agents with novel mechanisms or properties. Pseudomonas aeruginosa, a Gram-negative opportunistic nosocomial pathogen, is a model strain to study biofilm development and correlation between biofilm formation and infection. In this study, a recombinant hemolymph plasma lectin (rHPLOE) cloned from Taiwanese Tachypleus tridentatus was expressed in an Escherichia coli system. This rHPLOE was shown to have the following properties: (1) Binding to P. aeruginosa PA14 biofilm through a unique molecular interaction with rhamnose-containing moieties on bacteria, leading to reduction of extracellular di-rhamnolipid (a biofilm regulator); (2) decreasing downstream quorum sensing factors, and inhibiting biofilm formation; (3) dispersing the mature biofilm of P. aeruginosa PA14 to improve the efficacies of antibiotics; (4) reducing P. aeruginosa PA14 cytotoxicity to human lung epithelial cells in vitro and (5) inhibiting P. aeruginosa PA14 infection of zebrafish embryos in vivo. Taken together, rHPLOE serves as an anti-biofilm agent with a novel mechanism of recognizing rhamnose moieties in lipopolysaccharides, di-rhamnolipid and structural polysaccharides (Psl) in biofilms. Thus rHPLOE links glycan-recognition to novel anti-biofilm strategies against pathogenic bacteria.


Assuntos
Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Proteínas de Transporte/metabolismo , Pseudomonas aeruginosa/efeitos dos fármacos , Ramnose/metabolismo , Células A549 , Animais , Proteínas de Bactérias/metabolismo , Linhagem Celular Tumoral , Células Epiteliais/efeitos dos fármacos , Escherichia coli/metabolismo , Glicolipídeos/metabolismo , Caranguejos Ferradura/metabolismo , Humanos , Lectinas/metabolismo , Polissacarídeos Bacterianos/metabolismo , Percepção de Quorum/efeitos dos fármacos , Peixe-Zebra
4.
Antimicrob Agents Chemother ; 60(10): 6369-73, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27458227

RESUMO

Two antimicrobial P-113 peptide derivatives, P-113Du and P-113Tri, were investigated in this study. Notably, P-113Du and P-113Tri contained significant fractions of α-helix conformation and were less sensitive to high salt and low pH than P-113. Moreover, compared to P-113, these peptides exhibited increased antifungal activity against planktonic cells, biofilm cells, and clinical isolates of Candida albicans and non-albicans Candida spp. These results suggest that P-113Du and P-113Tri are promising candidates for development as novel antifungal agents.


Assuntos
Antifúngicos/química , Antifúngicos/farmacologia , Candida albicans/efeitos dos fármacos , Histatinas/farmacologia , Ácido Ascórbico/farmacologia , Biofilmes/efeitos dos fármacos , Avaliação Pré-Clínica de Medicamentos/métodos , Histatinas/química , Humanos , Concentração de Íons de Hidrogênio , Testes de Sensibilidade Microbiana , Plâncton/microbiologia , Conformação Proteica
5.
Mol Genet Genomics ; 289(5): 807-19, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24752399

RESUMO

Candida albicans is an opportunistic human pathogen that can form a biofilm on biotic or inert surfaces such as epithelia and clinical devices. In this study, we examine the formation of C. albicans biofilm by establishing a key gene-centered network based on protein-protein interaction (PPI) and gene expression datasets. Starting from C. albicans Cph1 and Efg1, transcription factors associated with morphogenesis of biofilm formation, a network elucidates the complex cellular process and predicts potential unknown components related to biofilm formation. Subsequently, we analyzed the functions of Mss11 among these identified proteins to test the efficiency of the proposed computational approach. MSS11-deleted mutants were compared with a wild-type strain, indicating that the mutant is defective in forming a mature biofilm and partially attenuates the virulence of C. albicans in an infected mouse model. Finally, a DNA microarray analysis was conducted to identify the potential target genes of C. albicans Mss11. The findings of this study clarify complex gene or protein interaction during the biofilm formation process of C. albicans, supporting the application of a systems biology approach to study fungal pathogenesis.


Assuntos
Biofilmes/crescimento & desenvolvimento , Candida albicans/fisiologia , Candidíase/microbiologia , Proteínas Fúngicas/fisiologia , Fatores de Transcrição/fisiologia , Animais , Candida albicans/patogenicidade , Feminino , Expressão Gênica , Regulação Fúngica da Expressão Gênica , Redes Reguladoras de Genes , Camundongos , Camundongos Endogâmicos BALB C , Virulência
6.
BMC Microbiol ; 14: 119, 2014 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-24885279

RESUMO

BACKGROUND: Tigecycline resistance in Acinetobacter baumannii is primarily acquired through overexpression of the AdeABC efflux pump. Besides AdeRS, other two-component regulatory systems (TCSs) involving the regulation of this transporter have not been clarified. RESULTS: In this study, we found that the TCS genes baeR and baeS are co-transcribed and function as stress responders under high osmotic conditions. The baeSR and adeAB genes showed increased transcription in both the laboratory-induced and clinical tigecycline-resistant strains compared with the wild-type strain. The deletion of baeR in the ATCC 17978 strain led to 67-73% and 68% reduction in adeA and adeB expression, respectively, with a resultant 2-fold decrease in the tigecycline minimal inhibition concentration (MIC). In contrast, the overexpression of baeR resulted in a doubled tigecycline MIC, with a more than 2-fold increase in adeA and adeB expression. The influence of baeR knockout on adeAB gene expression can also be observed in the laboratory-induced tigecycline-resistant strain. A time-kill assay showed that the baeR deletion mutant showed an approximate 1-log10 reduction in colony forming units (CFUs) relative to the wild-type strain when the tigecycline concentration was 0.25 µg/mL throughout the assay period. The wild-type phenotype could be restored by trans-complementation with pWH1266-kanr-baeR. Increasing the tigecycline concentration to 0.5 µg/mL produced an even more marked 4.7-log10 reduction in CFUs of the baeR deletion mutant at 8 h, while only a 2.1-log10 reduction was observed for the wild-type strain. CONCLUSIONS: Taken together, these data show for the first time that the BaeSR TCS influences the tigecycline susceptibility of A. baumannii through the positive regulation of the resistance-nodulation-division efflux pump genes adeA and adeB.


Assuntos
Acinetobacter baumannii/efeitos dos fármacos , Antibacterianos/farmacologia , Proteínas de Bactérias/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Minociclina/análogos & derivados , Proteínas Quinases/metabolismo , Transativadores/metabolismo , Acinetobacter baumannii/genética , Acinetobacter baumannii/fisiologia , Farmacorresistência Bacteriana , Regulação Bacteriana da Expressão Gênica , Testes de Sensibilidade Microbiana , Minociclina/farmacologia , Pressão Osmótica , Estresse Fisiológico , Tigeciclina
7.
Eukaryot Cell ; 12(6): 804-15, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23543673

RESUMO

The CCAAT motif is ubiquitous in promoters of eukaryotic genomes. The CCAAT-binding complex (CBC) is conserved across a wide range of organisms, specifically recognizes the CCAAT motif, and modulates transcription directly or in cooperation with other transcription factors. In Candida albicans, CBC is known to interact with the repressor Hap43 to negatively regulate iron utilization genes in response to iron deprivation. However, the extent of additional functions of CBC is unclear. In this study, we explored new roles of CBC in C. albicans and found that CBC pleiotropically regulates many virulence traits in vitro, including negative control of genes responsible for ribosome biogenesis and translation and positive regulation of low-nitrogen-induced filamentation. In addition, C. albicans CBC is involved in utilization of host proteins as nitrogen sources and in repression of cellular flocculation and adhesin gene expression. Moreover, our epistasis analyses suggest that CBC acts as a downstream effector of Rhb1-TOR signaling and controls low-nitrogen-induced filamentation via the Mep2-Ras1-protein kinase A (PKA)/mitogen-activated protein kinase (MAPK) pathway. Importantly, the phenotypes identified here are all independent of Hap43. Finally, deletion of genes encoding CBC components slightly attenuated C. albicans virulence in both zebrafish and murine models of infection. Our results thus highlight new roles of C. albicans CBC in regulating multiple virulence traits in response to environmental perturbations and, finally, suggest potential targets for antifungal therapies as well as extending our understanding of the pathogenesis of other fungal pathogens.


Assuntos
Fator de Ligação a CCAAT/genética , Candida albicans/genética , Candida albicans/patogenicidade , Proteínas Fúngicas/genética , Regulação Fúngica da Expressão Gênica , Animais , Fator de Ligação a CCAAT/metabolismo , Candida albicans/metabolismo , Candidíase/microbiologia , Candidíase/mortalidade , Proteínas de Transporte de Cátions/genética , Proteínas de Transporte de Cátions/metabolismo , Proteínas Fúngicas/metabolismo , GTP Fosfo-Hidrolases/genética , GTP Fosfo-Hidrolases/metabolismo , Ferro/metabolismo , Camundongos , Proteínas Quinases Ativadas por Mitógeno/genética , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Mutação , Regiões Promotoras Genéticas , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo , Transdução de Sinais , Análise de Sobrevida , Serina-Treonina Quinases TOR/genética , Serina-Treonina Quinases TOR/metabolismo , Virulência , Peixe-Zebra , Proteínas ras/genética , Proteínas ras/metabolismo
8.
Eukaryot Cell ; 11(2): 168-82, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22194462

RESUMO

Candida albicans is a major fungal pathogen in humans. In C. albicans, secreted aspartyl protease 2 (Sap2) is the most highly expressed secreted aspartic protease in vitro and is a virulence factor. Recent research links the small GTPase Rhb1 to C. albicans target of rapamycin (TOR) signaling in response to nitrogen availability. The results of this study show that Rhb1 is related to cell growth through the control of SAP2 expression when protein is the major nitrogen source. This process involves various components of the TOR signaling pathway, including Tor1 kinase and its downstream effectors. TOR signaling not only controls SAP2 transcription but also affects Sap2 protein levels, possibly through general amino acid control. DNA microarray analysis identifies other target genes downstream of Rhb1 in addition to SAP2. These findings provide new insight into nutrients, Rhb1-TOR signaling, and expression of C. albicans virulence factor.


Assuntos
Ácido Aspártico Endopeptidases/metabolismo , Candida albicans/enzimologia , Proteínas Fúngicas/metabolismo , GTP Fosfo-Hidrolases/metabolismo , Regulação Fúngica da Expressão Gênica , Proteínas Quinases/metabolismo , Ácido Aspártico Endopeptidases/genética , Candida albicans/genética , Candida albicans/metabolismo , Proteínas Fúngicas/genética , Mutação , Análise de Sequência com Séries de Oligonucleotídeos , Proteínas Quinases/genética , Transdução de Sinais , Virulência/genética
9.
Biochem J ; 441(3): 963-70, 2012 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-22023339

RESUMO

The opportunistic fungus Candida albicans causes oral thrush and vaginal candidiasis, as well as candidaemia in immunocompromised patients including those undergoing cancer chemotherapy, organ transplant and those with AIDS. We previously found that the AMPs (antimicrobial peptides) LL37 and hBD-3 (human ß-defensin-3) inhibited C. albicans viability and its adhesion to plastic. For the present study, the mechanism by which LL37 and hBD-3 reduced C. albicans adhesion was investigated. After AMP treatment, C. albicans adhesion to plastic was reduced by up to ~60% and was dose-dependent. Our previous study indicated that LL37 might interact with the cell-wall ß-1,3-exoglucanase Xog1p, which is involved in cell-wall ß-glucan metabolism, and consequently the binding of LL37 or hBD-3 to Xog1p might cause the decrease in adhesion. For the present study, Xog1p(41-438)-6H, an N-terminally truncated, active, recombinant construct of Xog1p and Xog1p fragments were produced and used in pull-down assays and ELISA in vitro, which demonstrated that all constructs interacted with both AMPs. Enzymatic analyses showed that LL37 and hBD-3 enhanced the ß-1,3-exoglucanase activity of Xog1p(41-438)-6H approximately 2-fold. Therefore elevated Xog1p activity might compromise cell-wall integrity and decrease C. albicans adhesion. To test this hypothesis, C. albicans was treated with 1.3 µM Xog1p(41-438)-6H and C. albicans adhesion to plastic decreased 47.7%. Taken together, the evidence suggests that Xog1p is one of the LL37/hBD-3 targets, and elevated ß-1,3-exoglucanase activity reduces C. albicans adhesion to plastic.


Assuntos
Candida albicans/fisiologia , Catelicidinas/fisiologia , Proteínas Fúngicas/metabolismo , Glucana 1,3-beta-Glucosidase/metabolismo , beta-Defensinas/fisiologia , Peptídeos Catiônicos Antimicrobianos , Candida albicans/genética , Candida albicans/crescimento & desenvolvimento , Candida albicans/metabolismo , Catelicidinas/genética , Catelicidinas/metabolismo , Catelicidinas/farmacologia , Adesão Celular/efeitos dos fármacos , Adesão Celular/genética , Parede Celular/efeitos dos fármacos , Parede Celular/genética , Parede Celular/metabolismo , Citotoxinas/genética , Citotoxinas/metabolismo , Citotoxinas/farmacologia , Citotoxinas/fisiologia , Relação Dose-Resposta a Droga , Regulação para Baixo , Avaliação Pré-Clínica de Medicamentos , Proteínas Fúngicas/genética , Proteínas Fúngicas/farmacologia , Proteínas Fúngicas/fisiologia , Glucana 1,3-beta-Glucosidase/genética , Glucana 1,3-beta-Glucosidase/farmacologia , Glucana 1,3-beta-Glucosidase/fisiologia , Humanos , Testes de Sensibilidade Microbiana , Organismos Geneticamente Modificados , Plásticos , Ligação Proteica/genética , beta-Defensinas/genética , beta-Defensinas/metabolismo , beta-Defensinas/farmacologia
10.
Microbiol Spectr ; 11(6): e0255123, 2023 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-37888991

RESUMO

IMPORTANCE: Candida albicans is a major human fungal pathogen, and antimicrobial peptides are key components of innate immunity. Studying the interplay between C. albicans and human antimicrobial peptides would enhance a better understanding of pathogen-host interactions. Moreover, potential applications of antimicrobial peptides in antifungal therapy have aroused great interest. This work explores new mechanisms of LL-37 against C. albicans and reveals the complex connection among calcium homeostasis, oxidative stress, signaling, and possibly organelle interaction. Notably, these findings support the possible use of antimicrobial peptides to prevent and treat fungal infections.


Assuntos
Candida albicans , Catelicidinas , Humanos , Candida albicans/metabolismo , Catelicidinas/metabolismo , Peptídeos Catiônicos Antimicrobianos/farmacologia , Cálcio , Peptídeos Antimicrobianos , Membrana Celular/metabolismo , Homeostase , Antifúngicos/farmacologia , Antifúngicos/uso terapêutico
11.
Microbiol Spectr ; 11(6): e0147123, 2023 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-37905800

RESUMO

IMPORTANCE: Of 123 identified isolates from the fruit surface, C. tropicalis was the most frequently found species, followed by Meyerozyma caribbica and Candida krusei. All three fluconazole-resistant C. tropicalis were non-susceptible to voriconazole and belonged to the same predominant genotype of azole-resistant C. tropicalis causing candidemia in patients in Taiwan. Our findings provide evidence that fruit should be washed before eaten not only to remove chemicals but also potential drug-resistant pathogenic microbes, especially for immunocompromised individuals. To keep precious treatment options in patients, we not only continuously implement antimicrobial stewardship in hospitals but also reducing/stopping the use of agricultural fungicide classes used in human medicine.


Assuntos
Antifúngicos , Candida tropicalis , Humanos , Antifúngicos/farmacologia , Antifúngicos/uso terapêutico , Candida tropicalis/genética , Frutas , Fluconazol/farmacologia , Voriconazol , Testes de Sensibilidade Microbiana , Farmacorresistência Fúngica
12.
Eukaryot Cell ; 10(2): 207-25, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21131439

RESUMO

Candida albicans is an opportunistic fungal pathogen that exists as normal flora in healthy human bodies but causes life-threatening infections in immunocompromised patients. In addition to innate and adaptive immunities, hosts also resist microbial infections by developing a mechanism of "natural resistance" that maintains a low level of free iron to restrict the growth of invading pathogens. C. albicans must overcome this iron-deprived environment to cause infections. There are three types of iron-responsive transcriptional regulators in fungi; Aft1/Aft2 activators in yeast, GATA-type repressors in many fungi, and HapX/Php4 in Schizosaccharomyces pombe and Aspergillus species. In this study, we characterized the iron-responsive regulator Hap43, which is the C. albicans homolog of HapX/Php4 and is repressed by the GATA-type repressor Sfu1 under iron-sufficient conditions. We provide evidence that Hap43 is essential for the growth of C. albicans under low-iron conditions and for C. albicans virulence in a mouse model of infection. Hap43 was not required for iron acquisition under low-iron conditions. Instead, it was responsible for repression of genes that encode iron-dependent proteins involved in mitochondrial respiration and iron-sulfur cluster assembly. We also demonstrated that Hap43 executes its function by becoming a transcriptional repressor and accumulating in the nucleus in response to iron deprivation. Finally, we found a connection between Hap43 and the global corepressor Tup1 in low-iron-induced flavinogenesis. Taken together, our data suggest a complex interplay among Hap43, Sfu1, and Tup1 to coordinately regulate iron acquisition, iron utilization, and other iron-responsive metabolic activities.


Assuntos
Candida albicans/fisiologia , Proteínas Fúngicas/metabolismo , Deficiências de Ferro , Proteínas Repressoras/metabolismo , Sequência de Aminoácidos , Animais , Candida albicans/patogenicidade , Candidíase/patologia , Núcleo Celular/metabolismo , Proliferação de Células , Feminino , Flavinas/biossíntese , Proteínas Fúngicas/genética , Deleção de Genes , Regulação Fúngica da Expressão Gênica , Humanos , Ferro/metabolismo , Rim/patologia , Camundongos , Camundongos Endogâmicos BALB C , Dados de Sequência Molecular , Proteínas Repressoras/genética , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Técnicas do Sistema de Duplo-Híbrido , Virulência
13.
J Fungi (Basel) ; 8(11)2022 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-36422017

RESUMO

The cell wall is the first interface for Candida albicans interaction with the surrounding environment and the host cells. Therefore, maintenance of cell wall integrity (CWI) is crucial for C. albicans survival and host-pathogen interaction. In response to environmental stresses, C. albicans undergoes cell wall remodeling controlled by multiple signaling pathways and transcription regulators. Here, we explored the role of the transcription factor Sfp1 in CWI. A deletion of the SFP1 gene not only caused changes in cell wall properties, cell wall composition and structure but also modulated expression of cell wall biosynthesis and remodeling genes. In addition, Cas5 is a known transcription regulator for C. albicans CWI and cell wall stress response. Interestingly, our results indicated that Sfp1 negatively controls the CAS5 gene expression by binding to its promoter element. Together, this study provides new insights into the regulation of C. albicans CWI and stress response.

14.
Free Radic Biol Med ; 192: 165-181, 2022 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-36126862

RESUMO

Seipin is encoded by the gene Berardinelli-Seip congenital lipodystrophy type 2 (BSCL2) and FLD1/SEI1 in yeast. The gain-of-function N88S mutation in the BSCL2 gene was identified in a cohort of autosomal dominant motor neuron diseases (MNDs) collectively known as seipinopathies. Previous work has shown that this mutation disrupts N-glycosylation, leading to the formation of inclusion bodies (IBs) and contributing to severe Endoplasmic Reticulum (ER) stress and cell death. In this work, we established a humanized yeast model of N88S seipinopathy that recapitulated the formation of IBs and activation of the unfolded protein response (UPR) observed in mammalian systems. Autophagy and the Hrd1-mediated endoplasmic reticulum-associated degradation (ERAD) were fully functional in cells expressing mutant homomers and WT-mutant heteromers of seipin, discarding the possibility that mutant seipin accumulate due to impaired protein quality control systems. Importantly, the N88S seipin form IBs that appear to induce changes in ER morphology, in association with Kar2 chaperone and the Hsp104 disaggregase. For the first time, we have determined that N88S homo-oligomers expressing cells present reduced viability, decreased antioxidant activity and increased oxidative damage associated with loss of mitochondrial membrane potential, higher reactive oxygen species (ROS) levels and lipid peroxidation. This was correlated with the activation of oxidative stress sensor Yap1. Moreover, activation of ERAD and UPR quality control mechanisms were essential for proper cell growth, and crucial to prevent excessive accumulation of ROS in cells expressing N88S homomers solely. Overall, this study provides new insights into the molecular underpinnings of these rare diseases and offers novel targets for potential pharmacological intervention.


Assuntos
Estresse do Retículo Endoplasmático , Subunidades gama da Proteína de Ligação ao GTP , Estresse Oxidativo , Humanos , Antioxidantes/metabolismo , Retículo Endoplasmático/metabolismo , Degradação Associada com o Retículo Endoplasmático , Subunidades gama da Proteína de Ligação ao GTP/genética , Subunidades gama da Proteína de Ligação ao GTP/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Corpos de Inclusão , Saccharomyces cerevisiae
15.
Microbiol Spectr ; 10(6): e0328522, 2022 12 21.
Artigo em Inglês | MEDLINE | ID: mdl-36416583

RESUMO

Rap1 (repressor activator protein 1) is a multifunctional protein, playing important roles in telomeric and nontelomeric functions in many eukaryotes. Candida albicans Rap1 has been previously shown to be involved in telomeric regulation, but its other functions are still mostly unknown. In this study, we found that the deletion of the RAP1 gene altered cell wall properties, composition, and gene expression. In addition, deletion of RAP1 affected C. albicans biofilm formation and modulated phagocytosis and cytokine release by host immune cells. Finally, the RAP1 gene deletion mutant showed attenuation of C. albicans virulence in a Galleria mellonella infection model. Therefore, these findings provide new insights into Rap1 functions that are particularly relevant to pathogenesis and virulence of C. albicans. IMPORTANCE C. albicans is an important fungal pathogen of humans. The cell wall is the outermost layer of C. albicans and is important for commensalism and infection by this pathogen. Moreover, the cell wall is also an important target for antifungals. Studies of how C. albicans maintains its cell wall integrity are critical for a better understanding of fungal pathogenesis and virulence. This work focuses on exploring unknown functions of C. albicans Rap1 and reveals its contribution to cell wall integrity, biofilm formation, and virulence. Notably, these findings will also improve our general understanding of complex machinery to control pathogenesis and virulence of fungal pathogens.


Assuntos
Antifúngicos , Candida albicans , Antifúngicos/uso terapêutico , Biofilmes , Candida albicans/genética , Candida albicans/metabolismo , Parede Celular/metabolismo , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Virulência , Animais , Mariposas
16.
Nat Commun ; 13(1): 102, 2022 01 10.
Artigo em Inglês | MEDLINE | ID: mdl-35013238

RESUMO

The systematic design of functional peptides has technological and therapeutic applications. However, there is a need for pattern-based search engines that help locate desired functional motifs in primary sequences regardless of their evolutionary conservation. Existing databases such as The Protein Secondary Structure database (PSS) no longer serves the community, while the Dictionary of Protein Secondary Structure (DSSP) annotates the secondary structures when tertiary structures of proteins are provided. Here, we extract 1.7 million helices from the PDB and compile them into a database (Therapeutic Peptide Design database; TP-DB) that allows queries of compounded patterns to facilitate the identification of sequence motifs of helical structures. We show how TP-DB helps us identify a known purification-tag-specific antibody that can be repurposed into a diagnostic kit for Helicobacter pylori. We also show how the database can be used to design a new antimicrobial peptide that shows better Candida albicans clearance and lower hemolysis than its template homologs. Finally, we demonstrate how TP-DB can suggest point mutations in helical peptide blockers to prevent a targeted tumorigenic protein-protein interaction. TP-DB is made available at http://dyn.life.nthu.edu.tw/design/ .


Assuntos
Aminoácidos/química , Peptídeos Antimicrobianos/química , Antineoplásicos/química , Software , Sequência de Aminoácidos , Aminoácidos/metabolismo , Animais , Peptídeos Antimicrobianos/metabolismo , Peptídeos Antimicrobianos/farmacologia , Antineoplásicos/metabolismo , Antineoplásicos/farmacologia , Bases de Dados de Proteínas , Desenho de Fármacos/métodos , Humanos , Simulação de Dinâmica Molecular , Mutagênese Sítio-Dirigida , Ligação Proteica , Conformação Proteica em alfa-Hélice , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/farmacologia , Relação Estrutura-Atividade
17.
BMC Bioinformatics ; 12: 281, 2011 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-21749690

RESUMO

BACKGROUND: Identifying key components in biological processes and their associations is critical for deciphering cellular functions. Recently, numerous gene expression and molecular interaction experiments have been reported in Saccharomyces cerevisiae, and these have enabled systematic studies. Although a number of approaches have been used to predict gene functions and interactions, tools that analyze the essential coordination of functional components in cellular processes still need to be developed. RESULTS: In this work, we present a new approach to study the cooperation of functional modules (sets of functionally related genes) in a specific cellular process. A cooperative module pair is defined as two modules that significantly cooperate with certain functional genes in a cellular process. This method identifies cooperative module pairs that significantly influence a cellular process and the correlated genes and interactions that are essential to that process. Using the yeast cell cycle as an example, we identified 101 cooperative module associations among 82 modules, and importantly, we established a cell cycle-specific cooperative module network. Most of the identified module pairs cover cooperative pathways and components essential to the cell cycle. We found that 14, 36, 18, 15, and 20 cooperative module pairs significantly cooperate with genes regulated in early G1, late G1, S, G2, and M phase, respectively. Fifty-nine module pairs that correlate with Cdc28 and other essential regulators were also identified. These results are consistent with previous studies and demonstrate that our methodology is effective for studying cooperative mechanisms in the cell cycle. CONCLUSIONS: In this work, we propose a new approach to identifying condition-related cooperative interactions, and importantly, we establish a cell cycle-specific cooperation module network. These results provide a global view of the cell cycle and the method can be used to discover the dynamic coordination properties of functional components in other cellular processes.


Assuntos
Proteínas de Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/citologia , Saccharomyces cerevisiae/genética , Ciclo Celular , Perfilação da Expressão Gênica , Regulação Fúngica da Expressão Gênica , Mitose , Saccharomyces cerevisiae/fisiologia , Proteínas de Saccharomyces cerevisiae/metabolismo , Transdução de Sinais
18.
J Fungi (Basel) ; 7(7)2021 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-34209722

RESUMO

Lactoferricin (Lfcin) is an amphipathic, cationic peptide derived from proteolytic cleavage of the N-lobe of lactoferrin (Lf). Lfcin and its derivatives possess broad-spectrum antibacterial and antifungal activities. However, unlike their antibacterial functions, the modes of action of Lfcin and its derivatives against pathogenic fungi are less well understood. In this study, the mechanisms of LfcinB15, a derivative of bovine Lfcin, against Candida albicans were, therefore, extensively investigated. LfcinB15 exhibited inhibitory activity against planktonic cells, biofilm cells, and clinical isolates of C. albicans and non-albicans Candida species. We further demonstrated that LfcinB15 is localized on the cell surface and vacuoles of C. albicans cells. Moreover, LfcinB15 uses several different methods to kill C. albicans, including disturbing the cell membrane, inducing reactive oxygen species (ROS) generation, and causing mitochondrial dysfunction. Finally, the Hog1 and Mkc1 mitogen-activated protein kinases were both activated in C. albicans cells in response to LfcinB15. These findings help us to obtain more insight into the complex mechanisms used by LfcinB15 and other Lfcin-derived peptides to fight fungal pathogens.

19.
BMC Bioinformatics ; 11: 53, 2010 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-20102611

RESUMO

BACKGROUND: Candida albicans is a commonly encountered fungal pathogen in humans. The formation of biofilm is a major virulence factor in C. albicans pathogenesis and is related to antidrug resistance of this organism. Although many factors affecting biofilm have been analyzed, molecular mechanisms that regulate biofilm formation still await to be elucidated. RESULTS: In this study, from the gene regulatory network perspective, we developed an efficient computational framework, which integrates different kinds of data from genome-scale analysis, for global screening of potential transcription factors (TFs) controlling C. albicans biofilm formation. S. cerevisiae information and ortholog data were used to infer the possible TF-gene regulatory associations in C. albicans. Based on TF-gene regulatory associations and gene expression profiles, a stochastic dynamic model was employed to reconstruct the gene regulatory networks of C. albicans biofilm and planktonic cells. The two networks were then compared and a score of relevance value (RV) was proposed to determine and assign the quantity of correlation of each potential TF with biofilm formation. A total of twenty-three TFs are identified to be related to the biofilm formation; ten of them are previously reported by literature evidences. CONCLUSIONS: The results indicate that the proposed screening method can successfully identify most known biofilm-related TFs and also identify many others that have not been previously reported. Together, this method can be employed as a pre-experiment screening approach that reveals new target genes for further characterization to understand the regulatory mechanisms in biofilm formation, which can serve as the starting point for therapeutic intervention of C. albicans infections.


Assuntos
Biofilmes , Candida albicans/genética , Biologia Computacional/métodos , Redes Reguladoras de Genes , Fatores de Transcrição/genética , Bases de Dados Genéticas , Perfilação da Expressão Gênica/métodos , Genoma Fúngico
20.
Infect Immun ; 78(6): 2512-21, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20308295

RESUMO

In this work, the zebrafish model organism was developed to obtain a minivertebrate host system for a Candida albicans infection study. We demonstrated that C. albicans can colonize and invade zebrafish at multiple anatomical sites and kill the fish in a dose-dependent manner. Inside zebrafish, we monitored the progression of the C. albicans yeast-to-hypha transition by tracking morphogenesis, and we monitored the corresponding gene expression of the pathogen and the early host immune response. We performed a zebrafish survival assay with different C. albicans strains (SC5314, ATCC 10231, an hgc1 mutant, and a cph1/efg1 double mutant) to determine each strain's virulence, and the results were similar to findings reported in previous mouse model studies. Finally, using zebrafish embryos, we monitored C. albicans infection and visualized the interaction between pathogen and host myelomonocytic cells in vivo. Taken together, the results of this work demonstrate that zebrafish can be a useful host model to study C. albicans pathogenesis, and they highlight the advantages of using the zebrafish model in future invasive fungal research.


Assuntos
Candida albicans/patogenicidade , Candidíase/patologia , Modelos Animais de Doenças , Animais , Candidíase/imunologia , Candidíase/microbiologia , Perfilação da Expressão Gênica , Regulação Fúngica da Expressão Gênica , Interações Hospedeiro-Patógeno , Hifas/crescimento & desenvolvimento , Análise de Sobrevida , Virulência , Peixe-Zebra
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