A trade-off between proliferation and defense in the fungal pathogen Cryptococcus at alkaline pH is controlled by the transcription factor GAT201.

Cryptococcus is a fungal pathogen whose virulence relies on proliferation in and dissemination to host sites, and on synthesis of a defensive yet metabolically costly polysaccharide capsule. Regulatory pathways required for Cryptococcus virulence include a GATA-like transcription factor, Gat201, that regulates Cryptococcal virulence in both capsule-dependent and capsule-independent ways. Here we show that Gat201 is part of a negative regulatory pathway that limits fungal survival. RNA-seq analysis found strong induction of GAT201 expression within minutes of transfer to host-like media at alkaline pH. Microscopy, growth curves, and colony forming units to test viability show that in host-like media at alkaline pH wild-type Cryptococcus neoformans yeast cells produce capsule but do not bud or maintain viability, while gat201Δ cells make buds and maintain viability, yet fail to produce capsule. GAT201 is required for transcriptional upregulation of a specific set of genes in host-like media, the majority of which are direct Gat201 targets. Evolutionary analysis shows that Gat201 is conserved within pathogenic fungi but lost in model yeasts. This work identifies the Gat201 pathway as controlling a trade-off between proliferation, which we showed is repressed by GAT201, and production of defensive capsule. The assays established here will allow characterisation of the mechanisms of action of the Gat201 pathway. Together, our findings urge improved understanding of the regulation of proliferation as a driver of fungal pathogenesis.

Patients' perspectives regarding long-term warfarin therapy and the potential transition to new oral anticoagulant therapy.

OBJECTIVES: To examine patients' perspectives regarding long-term vitamin K antagonist (VKA) therapy and the potential transition to new oral anticoagulants (NOACs) such as dabigatran and rivaroxaban, and to determine if factors such as residential location affect these opinions. DESIGN SETTING AND PARTICIPANTS: Patients on VKA therapy for at least 12 weeks completed a questionnaire specifically designed for the study. They were recruited while attending point-of-care international normalized ratio (INR) testing at six South Australian general practice clinics during the period July-September 2013. MAIN OUTCOME MEASURES: Opinions of current VKA therapy, level of awareness of NOACs, and ratings of potential benefits and deterrents of transition to NOACs were sought. RESULTS: Data from 290 participants were available for analysis (response rate 95.4%). The majority of the sample (79.5%, 229/288) were either satisfied or very satisfied with current VKA therapy. The mean score for the potential benefits of transition to NOACs was 7.6 (±4.2) out of a possible 20, which was significantly lower than the mean score 10.9 (±4.5) for the perceived deterrents to transition (p < 0.001). Rural patients (82.0%, 82/100) were significantly more likely (p = 0.001) to have not heard of NOACs than metropolitan patients (50.3%, 95/189) and also perceived significant less benefits in a transition to NOACs (p = 0.001). CONCLUSION: When considering potential transition from VKAs to NOACs it is important for prescribers to consider that some patients, in particular those from a rural location, may not perceive a significant benefit in transitioning or may have particular concerns in this area.