Transcription Factor PrtT Controls Expression of Multiple Secreted Proteases in the Human Pathogenic Mold Aspergillus fumigatus

ABSTRACT The role of secreted proteases in the virulence of the pathogenic fungus Aspergillus fumigatus remains controversial. Recently, the Aspergillus niger transcription factor PrtT was shown to control the expression of multiple secreted proteases. In this work, the gene which encodes the PrtT homolog in A. fumigatus was cloned and its function analyzed using a deletion mutant strain. Deletion of A. fumigatus prtT resulted in the loss of secreted protease activity. The expression of six secreted proteases (ALP, MEP, Dpp4, CpdS, AFUA_2G17330, and AFUA_7G06220) was markedly reduced. Culture filtrates from the prtT deletion strain exhibited reduced killing of lung epithelial cells and lysis of erythrocytes. However, the prtT deletion strain did not exhibit altered virulence in lung-infected mice. These results suggest that PrtT is not a significant virulence factor in A. fumigatus.

Download Full-text

Profiling transcription factor sub-networks in type I interferon signaling and in response to SARS-CoV-2 infection

10.1101/2021.01.25.428122 ◽

2021 ◽

Author(s):

Chilakamarti V. Ramana

Keyword(s):

Gene Expression ◽

Transcription Factor ◽

Transcription Factors ◽

Immune Modulation ◽

Type I Interferon ◽

Lung Epithelial Cells ◽

Type I ◽

Interferon Signaling ◽

Lung Epithelial

AbstractType I interferons (IFN α/β) play a central role in innate immunity to respiratory viruses, including coronaviruses. Genetic defects in type I interferon signaling were reported in a significant proportion of critically ill CoOVID-19 patients. Extensive studies on interferon-induced intracellular signal transduction pathways led to the elucidation of the Jak-Stat pathway. Furthermore, advances in gene expression profiling by microarrays have revealed that type I interferon rapidly induced multiple transcription factor mRNA levels. In this study, transcription factor profiling in the transcriptome was used to gain novel insights into the role of inducible transcription factors in response to type I interferon signaling in immune cells and in lung epithelial cells after SARS-CoV-2 infection. Modeling the interferon-inducible transcription factor mRNA data in terms of distinct sub-networks based on biological functions such as antiviral response, immune modulation, and cell growth revealed enrichment of specific transcription factors in mouse and human immune cells. The evolutionarily conserved core type I interferon gene expression consists of the inducible transcriptional factor mRNA of the antiviral response sub-network and enriched in granulocytes. Analysis of the type I interferon-inducible transcription factor sub-networks as distinct protein-protein interaction pathways revealed insights into the role of critical hubs in signaling. Interrogation of multiple microarray datasets revealed that SARS-CoV-2 induced high levels of IFN-beta and interferon-inducible transcription factor mRNA in human lung epithelial cells. Transcription factor mRNA of the three major sub-networks regulating antiviral, immune modulation, and cell growth were differentially regulated in human lung epithelial cell lines after SARS-CoV-2 infection and in the tissue samples of COVID-19 patients. A subset of type I interferon-inducible transcription factors and inflammatory mediators were specifically enriched in the lungs and neutrophils of Covid-19 patients. The emerging complex picture of type I IFN transcriptional regulation consists of a rapid transcriptional switch mediated by the Jak-Stat cascade and a graded output of the inducible transcription factor activation that enables temporal regulation of gene expression.

Download Full-text

HbxB Is a Key Regulator for Stress Response and β-Glucan Biogenesis in Aspergillus nidulans

Microorganisms ◽

10.3390/microorganisms9010144 ◽

2021 ◽

Vol 9 (1) ◽

pp. 144

Author(s):

Sung-Hun Son ◽

Mi-Kyung Lee ◽

Ye-Eun Son ◽

Hee-Soo Park

Keyword(s):

Transcription Factor ◽

Transcription Factors ◽

Aspergillus Nidulans ◽

Deletion Mutant ◽

Phenotypic Analysis ◽

Spore Viability ◽

Fungal Development ◽

Expression Of Genes ◽

Trehalose Biosynthesis

Homeobox transcription factors are conserved in eukaryotes and act as multi-functional transcription factors in filamentous fungi. Previously, it was demonstrated that HbxB governs fungal development and spore viability in Aspergillus nidulans. Here, the role of HbxB in A. nidulans was further characterized. RNA-sequencing revealed that HbxB affects the transcriptomic levels of genes associated with trehalose biosynthesis and response to thermal, oxidative, and radiation stresses in asexual spores called conidia. A phenotypic analysis found that hbxB deletion mutant conidia were more sensitive to ultraviolet stress. The loss of hbxB increased the mRNA expression of genes associated with β-glucan degradation and decreased the amount of β-glucan in conidia. In addition, hbxB deletion affected the expression of the sterigmatocystin gene cluster and the amount of sterigmatocystin. Overall, these results indicated that HbxB is a key transcription factor regulating trehalose biosynthesis, stress tolerance, β-glucan degradation, and sterigmatocystin production in A.nidulans conidia.

Download Full-text

MC1568 inhibits HDAC6/8 activity and influenza A virus replication in lung epithelial cells: role of Hsp90 acetylation

Future Medicinal Chemistry ◽

10.4155/fmc-2016-0073 ◽

2016 ◽

Vol 8 (17) ◽

pp. 2017-2031 ◽

Cited By ~ 16

Author(s):

Simona Panella ◽

Maria Elena Marcocci ◽

Ignacio Celestino ◽

Sergio Valente ◽

Clemens Zwergel ◽

...

Keyword(s):

Epithelial Cells ◽

Influenza A Virus ◽

Virus Replication ◽

Influenza A ◽

Lung Epithelial Cells ◽

Lung Epithelial

Download Full-text

HIV-1 Productively Infects and Integrates in Bronchial Epithelial Cells

Frontiers in Cellular and Infection Microbiology ◽

10.3389/fcimb.2020.612360 ◽

2021 ◽

Vol 10 ◽

Cited By ~ 1

Author(s):

Dinesh Devadoss ◽

Shashi P. Singh ◽

Arpan Acharya ◽

Kieu Chinh Do ◽

Palsamy Periyasamy ◽

...

Keyword(s):

Epithelial Cells ◽

Bronchial Epithelial Cells ◽

Lung Epithelial Cells ◽

People Living With Hiv ◽

Sequencing Analysis ◽

Hiv Reservoirs ◽

Bronchial Epithelial ◽

Lung Epithelial ◽

Hiv 1

BackgroundThe role of lung epithelial cells in HIV-1-related lung comorbidities remains unclear, and the major hurdle in curing HIV is the persistence of latent HIV reservoirs in people living with HIV (PLWH). The advent of combined antiretroviral therapy has considerably increased the life span; however, the incidence of chronic lung diseases is significantly higher among PLWH. Lung epithelial cells orchestrate the respiratory immune responses and whether these cells are productively infected by HIV-1 is debatable.MethodsNormal human bronchial epithelial cells (NHBEs) grown on air–liquid interface were infected with X4-tropic HIV-1LAV and examined for latency using latency-reversing agents (LRAs). The role of CD4 and CXCR4 HIV coreceptors in NHBEs were tested, and DNA sequencing analysis was used to analyze the genomic integration of HIV proviral genes, Alu-HIVgag-pol, HIV-nef, and HIV-LTR. Lung epithelial sections from HIV-infected humans and SHIV-infected macaques were analyzed by FISH for HIV-gag-pol RNA and epithelial cell-specific immunostaining.Results and DiscussionNHBEs express CD4 and CXCR4 at higher levels than A549 cells. NHBEs are infected with HIV-1 basolaterally, but not apically, by X4-tropic HIV-1LAV in a CXCR4/CD4-dependent manner leading to HIV-p24 antigen production; however, NHBEs are induced to express CCR5 by IL-13 treatment. In the presence of cART, HIV-1 induces latency and integration of HIV provirus in the cellular DNA, which is rescued by the LRAs (endotoxin/vorinostat). Furthermore, lung epithelial cells from HIV-infected humans and SHIV-infected macaques contain HIV-specific RNA transcripts. Thus, lung epithelial cells are targeted by HIV-1 and could serve as potential HIV reservoirs that may contribute to the respiratory comorbidities in PLWH.

Download Full-text

The Putative APSES Transcription Factor RgdA Governs Growth, Development, Toxigenesis, and Virulence in Aspergillus fumigatus

mSphere ◽

10.1128/msphere.00998-20 ◽

2020 ◽

Vol 5 (6) ◽

Author(s):

Sang-Cheol Jun ◽

Yong-Ho Choi ◽

Min-Woo Lee ◽

Jae-Hyuk Yu ◽

Kwang-Soo Shin

Keyword(s):

Transcription Factor ◽

Aspergillus Fumigatus ◽

Molecular Mechanisms ◽

Pathogenic Fungus ◽

Mrna Levels ◽

Transcript Levels ◽

Content Type ◽

Asexual Sporulation ◽

Human Pathogenic Fungus ◽

Growth Development

ABSTRACT The APSES transcription factor (TF) in Aspergillus species is known to govern diverse cellular processes, including growth, development, and secondary metabolism. Here, we investigated functions of the rgdA gene (Afu3g13920) encoding a putative APSES TF in the opportunistic human-pathogenic fungus Aspergillus fumigatus. The rgdA deletion resulted in significantly decreased hyphal growth and asexual sporulation. Consistently, transcript levels of the key asexual developmental regulators abaA, brlA, and wetA were decreased in the ΔrgdA mutant compared to those in the wild type (WT). Moreover, ΔrgdA resulted in reduced spore germination rates and elevated transcript levels of genes associated with conidium dormancy. The conidial cell wall hydrophobicity and architecture were changed, and levels of the RodA protein were decreased in the ΔrgdA mutant. Comparative transcriptomic analyses revealed that the ΔrgdA mutant showed higher mRNA levels of gliotoxin (GT)-biosynthetic genes and GT production. While the ΔrgdA mutant exhibited elevated production of GT, ΔrgdA strains showed reduced virulence in the mouse model. In addition, mRNA levels of genes associated with the cyclic AMP (cAMP)-protein kinase A (PKA) signaling pathway and the SakA mitogen-activated protein (MAP) kinase pathway were increased in the ΔrgdA mutant. In summary, RgdA plays multiple roles in governing growth, development, GT production, and virulence which may involve attenuation of PKA and SakA signaling. IMPORTANCE Immunocompromised patients are susceptible to infections with the opportunistic human-pathogenic fungus Aspergillus fumigatus. This fungus causes systemic infections such as invasive aspergillosis (IA), which is one of the most life-threatening fungal diseases. To control this serious disease, it is critical to identify new antifungal drug targets. In fungi, the transcriptional regulatory proteins of the APSES family play crucial roles in controlling various biological processes, including mating, asexual sporulation and dimorphic growth, and virulence traits. This study found that a putative APSES transcription factor, RgdA, regulates normal growth, asexual development, conidium germination, spore wall architecture and hydrophobicity, toxin production, and virulence in A. fumigatus. Better understanding the molecular mechanisms of RgdA in human-pathogenic fungi may reveal a novel antifungal target for future drug development.

Download Full-text

Role of protein kinase C in cytokine secretion by lung epithelial cells during infection withParacoccidioides brasiliensis

Pathogens and Disease ◽

10.1093/femspd/ftv045 ◽

2015 ◽

Vol 73 (7) ◽

pp. ftv045 ◽

Cited By ~ 4

Author(s):

Cristiane Alcantara ◽

Paloma Korehisa Maza ◽

Bianca Carla Silva Campitelli Barros ◽

Erika Suzuki

Keyword(s):

Protein Kinase C ◽

Protein Kinase ◽

Epithelial Cells ◽

Lung Epithelial Cells ◽

Cytokine Secretion ◽

Kinase C ◽

Lung Epithelial

Download Full-text

Insights in the molecular mechanisms of an azole stress adapted laboratory-generated Aspergillus fumigatus strain

Medical Mycology ◽

10.1093/mmy/myaa118 ◽

2021 ◽

Author(s):

Marion Aruanno ◽

Samantha Gozel ◽

Isabelle Mouyna ◽

Josie E Parker ◽

Daniel Bachmann ◽

...

Keyword(s):

Transcription Factor ◽

Aspergillus Fumigatus ◽

Molecular Mechanisms ◽

Drug Transporters ◽

Major Facilitator Superfamily ◽

Ergosterol Biosynthesis ◽

Azole Resistance ◽

Drug Transporter

Abstract Aspergillus fumigatus is the main cause of invasive aspergillosis, for which azole drugs are the first-line therapy. Emergence of pan-azole resistance among A. fumigatus is concerning and has been mainly attributed to mutations in the target gene (cyp51A). However, azole resistance may also result from other mutations (hmg1, hapE) or other adaptive mechanisms. We performed microevolution experiment exposing an A. fumigatus azole-susceptible strain (Ku80) to sub-minimal inhibitory concentration of voriconazole to analyze emergence of azole resistance. We obtained a strain with pan-azole resistance (Ku80R), which was partially reversible after drug relief, and without mutations in cyp51A, hmg1, and hapE. Transcriptomic analyses revealed overexpression of the transcription factor asg1, several ATP-binding cassette (ABC) and major facilitator superfamily transporters and genes of the ergosterol biosynthesis pathway in Ku80R. Sterol analysis showed a significant decrease of the ergosterol mass under voriconazole exposure in Ku80, but not in Ku80R. However, the proportion of the sterol compounds was similar between both strains. To further assess the role of transporters, we used the ABC transporter inhibitor milbemycine oxime (MLB). MLB inhibited transporter activity in both Ku80 and Ku80R and demonstrated some potentiating effect on azole activity. Criteria for synergism were reached for MLB and posaconazole against Ku80. Finally, deletion of asg1 revealed some role of this transcription factor in controlling drug transporter expression, but had no impact on azole susceptibility. This work provides further insight in mechanisms of azole stress adaptation and suggests that drug transporters inhibition may represent a novel therapeutic target. Lay Summary A pan-azole-resistant strain was generated in vitro, in which drug transporter overexpression was a major trait. Analyses suggested a role of the transporter inhibitor milbemycin oxime in inhibiting drug transporters and potentiating azole activity.

Download Full-text

Expression and role of E- and P-cadherin adhesion molecules in embryonic histogenesis. I. Lung epithelial morphogenesis

Development ◽

10.1242/dev.105.2.263 ◽

1989 ◽

Vol 105 (2) ◽

pp. 263-270 ◽

Cited By ~ 3

Author(s):

Y. Hirai ◽

A. Nose ◽

S. Kobayashi ◽

M. Takeichi

Keyword(s):

Monoclonal Antibody ◽

Cell Adhesion ◽

Epithelial Cells ◽

Adhesion Molecules ◽

Lung Epithelial Cells ◽

Early Developmental Stage ◽

Subtle Effect ◽

Lung Epithelial ◽

Cell Cell

The role of Ca2+-dependent cell-cell adhesion molecules, E- and P-cadherins, in the histogenesis of mouse embryonic lung was studied. All epithelial cells of the lung express both E- and P-cadherin at the early developmental stage. P-cadherin, however, gradually disappears during development, initially from the main bronchi and eventually from all epithelial cells. When a monoclonal antibody to E-cadherin (ECCD-1) was added to monolayer cultures of lung epithelial cells, it induced a partial disruption of their cell-cell adhesion, while a monoclonal antibody to P-cadherin (PCD-1) showed a subtle effect. A mixture of the two antibodies, however, displayed a synergistic effect. We then tested the effect of the antibodies on the morphogenesis of lung primordia using an organ culture system. In control media, the explants formed typical bronchial trees. In the presence of ECCD-1, the explants grew up at the same rate as in the control, but their morphogenesis was affected. The control explants formed round epithelial lobules with an open luminal space at the tips of the bronchial trees, whereas the lobules of explants incubated with ECCD-1 tended to be flat and devoid of the luminal space. PCD-1 showed a similar but very small effect. A mixture of the two antibodies, however, showed a stronger effect: the branching of epithelia was partially suppressed and the arrangement of epithelial cells was distorted in many places. These results suggest that E- and P-cadherin have a synergistic role in the organization of epithelial cells in lung morphogenesis.

Download Full-text