# Cryptococcus neoformans factors contributing to penetration of the blood-brain barrier

> **NIH NIH R21** · JOHNS HOPKINS UNIVERSITY · 2020 · $245,625

## Abstract

Cryptococcus neoformans factors contributing to penetration of the blood-brain barrier
Abstract
Cryptococcus neoformans causes life-threating central nervous system (CNS) infection in
immunocompromised individuals such as HIV-1-infected patients, resulting in over 180,000 deaths annually.
Infection with C. neoformans starts with inhalation of fungal cells from environment, followed by
extrapulmonary spread, which leads to hematogenous dissemination to target organs, most commonly
resulting in CNS infection. Several lines of evidence of human cases and experimental animal models of C.
neoformans CNS infection indicate that circulating C. neoformans penetrates into the brain initially via the
cerebral capillaries. Since C. neoformans entry into the brain occurred in the cerebral microvasculature, we
and others used the in vitro blood-brain barrier model with human brain microvascular endothelial cells
(HBMEC) to investigate C. neoformans penetration of the blood-brain barrier. We showed that C. neoformans
strains exhibited the ability to traverse the HBMEC monolayer in vitro and penetrate into the brain in vivo in the
mouse model of experimental hematogenous C. neoformans CNS infection, but the underlying mechanisms
remain incompletely understood. We and others showed that C. neoformans exploits cryptococcal factors for
penetration of the blood-brain barrier, but determination of such factors remains incomplete. We generated
genome-scale sgRNA library from C. neoformans genomic DNA. Each sgRNA cassette serves as a genetic
barcode for mutation tracking, which allows high-throughput screen by deep sequencing. We hypothesize that
this library allows genome-wide screen of C. neoformans factors contributing to penetration of the blood-brain
barrier. This hypothesis is supported by our identification of cryptococcal factors using our in vitro (transcytosis
assays in HBMEC monolayer) and in vivo blood-brain barrier models (animals models of cryptococcal
penetration into the brain following intravenous and intranasal inoculations). Our proof of concept study with
two knock-out mutants demonstrated that such C. neoformans factors contributed to penetration of the blood-
brain barrier in vitro and in vivo. These findings suggest that C. neoformans factors identified from our genome-
wide screen method are likely to contribute to penetration of the blood-brain barrier, the essential step in the
development of C. neoformans CNS infection. The innovative aspect of this application is to investigate how C.
neoformans penetrates the blood-brain barrier by elucidating newly identified cryptococcal factors. The
information derived from this application will provide a new paradigm for investigating the pathogenesis of C.
neoformans CNS infection.

## Key facts

- **NIH application ID:** 10079284
- **Project number:** 1R21AI155009-01
- **Recipient organization:** JOHNS HOPKINS UNIVERSITY
- **Principal Investigator:** Brendan Cormack
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $245,625
- **Award type:** 1
- **Project period:** 2020-06-01 → 2022-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10079284

## Citation

> US National Institutes of Health, RePORTER application 10079284, Cryptococcus neoformans factors contributing to penetration of the blood-brain barrier (1R21AI155009-01). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10079284. Licensed CC0.

---

*[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*