# Enzymatic approach for targeting mannans/EPS to disrupt cross-kingdom cariog

> **NIH NIH R01** · UNIVERSITY OF PENNSYLVANIA · 2021 · $344,138

## Abstract

ABSTRACT
Microbiological studies reveal a direct association between early-childhood caries (ECC) and the presence of
Candida albicans, along with high levels of Streptococcus mutans in plaque-biofilms. Previous in vitro and in
vivo studies demonstrated that C. albicans and S. mutans develop a symbiotic relationship, enhancing the
severity of dental caries. This bacterial-fungal interaction is mediated by S. mutans exoenzymes termed
glucosyltransferases (Gtfs). The Gtfs binds avidly to the fungal surface and produces exopolysaccharides
(EPS) that promotes the development of cariogenic cross-kingdom biofilms. Our previous R03 supported
(DE025728) studies demonstrated that N- and O-linked mannans on the C. albicans cell wall play key roles in
this process. Mutant strains defective in mannans showed severely reduced GtfB binding (vs wild type), which
in turn impaired EPS production and abrogated mixed-species biofilm formation in vivo, revealing potential
antibioflm targets. Thus, we propose to further elucidate the mechanisms of GtfB binding/EPS production, and
assess whether an enzymatic strategy targeting the ligand-binding function could prevent cariogenic biofilm
development. We will use readily available α- (and β-) mannosidases for mannan degradation on Candida cell
wall and glucanohydrolases for EPS digestion in situ. We hypothesize that the enzyme combination therapy
will disrupt the GtfB binding sites on C. albicans surface and concomitantly digest the EPS produced by S.
mutans Gtfs, thereby blocking cross-kingdom biofilm formation and preventing the onset of severe caries in
vivo. To support our hypothesis, Aim 1 will characterize the Gtf binding-function mechanism using genetics
(mutant strains) and biochemical (enzymatic) approaches in conjunction with spectroscopy-fluorescence and
biophysical methods. Specifically, we will assess the impact of mannan-cleavage on Gtf binding/activity and
EPS production. In parallel, we will assess the optimal amounts and combinations of enzymes to disrupt C.
albicans-S. mutans interactions and biofilm formation. The efficacy of optimized dosages to biofilms will be
evaluated in Aim 2. Then, we will assess the disruption of biofilm development and cariogenicity on tooth-
enamel using our newly developed super-resolution confocal-surface topography system. Real-time dynamics
of cross-kingdom interaction, biofilm formation, in situ pH, metabolic activity, development of enamel lesions,
and biofilm detachment will be observed. In addition, we will test clinical isolates of S. mutans and C. albicans
from ECC-patients. The most effective dosage/combination of enzymes will be evaluated in vivo. In Aim 3, we
will determine antibiofilm and anticaries efficacy of the enzymatic therapy using a well-established rodent
model of ECC. We will investigate the impact of this therapeutic approach in preventing the onset and severity
of caries lesions. The influences on bacterial-fungal levels and plaque microbiome will b...

## Key facts

- **NIH application ID:** 10189551
- **Project number:** 5R01DE027970-04
- **Recipient organization:** UNIVERSITY OF PENNSYLVANIA
- **Principal Investigator:** Geelsu Hwang
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $344,138
- **Award type:** 5
- **Project period:** 2018-07-01 → 2023-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10189551

## Citation

> US National Institutes of Health, RePORTER application 10189551, Enzymatic approach for targeting mannans/EPS to disrupt cross-kingdom cariog (5R01DE027970-04). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10189551. Licensed CC0.

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