Role of phospholipids in antifungal drug resistance in cryptococcus neoformans

Active Project Grant Awarded Last action

Award ID
R01AI155647
Recipient
Awarding agency
Obligated
$4,549,782

Award facts

Assistance listing
93.855 Allergy and Infectious Diseases Research
Completion date 87% complete
Place of performance
Newark, NJ 07107, USA

Award details come from USAspending.gov.

Description

As the agency reported it.

Abstract
Cryptococcus neoformans and its sibling species c. Gattii cause cryptococcosis, a deadly fungal disease that accounts for over 15% of HIV/aids related deaths. Treatment options for cryptococcosis remain limited to two drug classes that are either highly toxic (polyenes) or exert a fungistatic effect (triazoles) that necessitate long treatment regimens and can induce drug resistance. The third antifungal drug class, echinocandins, shows low toxicity and is fungicidal against some prevalent fungal pathogens. However, cryptococcus species are resistant to echinocandins through an unknown resistance mechanism. We found that loss of CDC50, the regulatory subunit of lipid flippase, an enzyme that maintains asymmetry of the membrane lipid bilayers and regulates intracellular vesicle trafficking, sensitizes c. Neoformans to the echinocandin drug caspofungin and several triazoles. We further showed that the CDC50 mutant abolishes lipid flippase activity. We also found that this CDC50-mediated echinocandin resistance requires a mechanosensitive calcium channel protein, CRM1, which modulates intracellular calcium homeostasis. Strikingly, we discovered that lipid flippase function is essential for virulence in a murine model of cryptococcosis, suggesting that lipid flippase may be a novel antifungal drug target. In this project, our goals are to determine how lipid flippase mediates cryptococcal echinocandin resistance, and to conduct proof-of-principle studies of antibody-based inhibitors targeting flippase function as novel therapeutics for cryptococcus infections. We hypothesize that c. Neoformans has a unique plasma membrane structure and that loss of lipid flippase alters that structure to promote the interaction of caspofungin with its target and compromises fungal drug resistance mechanisms. We propose three aims to test our hypothesis. In aim 1, we will elucidate how loss of CDC50 changes membrane structure to promote the interaction of caspofungin with its membrane target SS-1,3-d-glucan synthase (FKS1). Aim 2 will identify the downstream drug resistance pathways that are compromised by the absence of CDC50, which disrupts intracellular calcium homeostasis and promotes cell death. In aim 3, we will develop an antibody FAB fragment and a stable peptide against the exoplasmic loop of CDC50, which is essential for flippase function. We will validate how inhibitors sensitize c. Neoformans to antifungal drugs and macrophage killing in vitro and in vivo in animal models. The region of CDC50 targeted by this antibody-based approach has low sequence homology to its human counterpart, and our preliminary studies showed that an antibody raised against this region is fungal- specific, reducing the chance of off-target effects. The impact of this study to elucidate the mechanisms underlying lipid flippase mediated drug resistance in c. Neoformans will be developing strategies for exploiting echinocandin drugs to effectively treat cryptococci and other resistant fungal pathogens. Our successful development of antibody-based inhibitors will establish a new avenue of research and drug development against other membrane proteins in fungi and bacteria.

Transactions

Action Obligated Date
Amendment $547,390
Amendment $550,814
Amendment $559,162
Amendment -$310,371
Amendment $310,371
Amendment $310,371
Amendment -$310,371
Amendment $567,300
Amendment $0
Amendment $0
Amendment $567,300
Amendment $0
Amendment $567,300
Amendment $595,258
Original award $595,258
Show all 15

Subawards

Subrecipient Amount Awarded
Seton Hall University Role of fungal phospholipids in Cryptococcus resistance against antifungal drugs $48,154
Seton Hall University $47,554

Quick answers

Who received award R01AI155647?

R01AI155647 was awarded to Rutgers The State University Of New Jersey by National Institute of Allergy and Infectious Diseases (National Institutes of Health) on July 1, 2022.

How much is award R01AI155647 worth?

$4,549,782 has been obligated on R01AI155647.

On GovTribe

See this award's full record

  • Every transaction and subaward
  • The recipient's other awards and teaming partners
  • Similar grant awards
  • Ask GovTribe AI about this award
Try for free Login