Homeostatic control of an iron repressor in a GI tract resident
- Institut Pasteur of Shanghai, China
- Shanghai Jiao Tong University, China
- Army Medical University, China
Abstract
The transition metal iron plays a crucial role in living cells. However, high levels of iron are potentially toxic through the production of reactive oxygen species (ROS), serving as a deterrent to the commensal fungus Candida albicans for colonization in the iron-rich gastrointestinal (GI) tract. We observe that the mutant lacking an iron-responsive transcription factor Hap43 is hyper-fit for colonization in murine gut. We demonstrate that high iron specifically triggers multiple post-translational modifications (PTMs) and proteasomal degradation of Hap43, a vital process guaranteeing the precision of intestinal ROS detoxification. Reduced levels of Hap43 de-repress the expression of antioxidant genes and therefore alleviate the deleterious ROS derived from iron metabolism. Our data reveal that Hap43 functions as a negative regulator for oxidative stress-adaptation of C. albicans to gut colonization and thereby provide a new insight into understanding the interplay between iron homeostasis and fungal commensalism.
Data availability
All data generated or analysed during this study are included in the manuscript and supporting file; Source Data files have been provided for all Figures.
Article and author information
Author details
Funding
The MOST Key R&D Program of China (2022YFC2303200)
- Changbin Chen
The National Natural Science Foundation (31600119)
- Xinhuang Huang
The Natural Science Foundation of Shanghai (20ZR1463800)
- Xinhuang Huang
The Natural Science Foundation of Shanghai (15ZR1444400)
- Xinhuang Huang
The MOST Key R&D Program of China (2022YFC2304700)
- Lin Zhong
The National Natural Science Foundation (32170195)
- Changbin Chen
The Shanghai Municipal Science and Technology Major Project (2019SHZDZX02)
- Changbin Chen
The Open Project of the State Key Laboratory of Trauma, Burns and Combined Injury, Third Military Medical University (SKLKF201803)
- Changbin Chen
The Special Program of PLA (19SWAQ18)
- Huaping Liang
National Postdoctoral Fellowship (No.312780)
- Yuanyuan Wang
Shanghai Post-doctoral Excellence Program (No.2022647)
- Yuanyuan Wang
The National Natural Science Foundation (32070146)
- Xinhuang Huang
The funders had role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Animal experimentation: All animal experiments were carried out in strict accordance with the regulations in the Guide for the Care and Use of Laboratory Animals issued by the Ministry of Science and Technology of the People's Republic of China. All efforts were made to minimize suffering. The protocol was approved by IACUC at the Institut Pasteur of Shanghai, Chinese Academy of Sciences (Permit Number: A160291).
Copyright
© 2023, Wang et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
Metrics
-
- 483
- views
-
- 85
- downloads
-
- 1
- citations
Views, downloads and citations are aggregated across all versions of this paper published by eLife.
Download links
A two-part list of links to download the article, or parts of the article, in various formats.
Downloads (link to download the article as PDF)
Open citations (links to open the citations from this article in various online reference manager services)
Cite this article (links to download the citations from this article in formats compatible with various reference manager tools)
Homeostatic control of an iron repressor in a GI tract resident
eLife 12:e86075.
https://doi.org/10.7554/eLife.86075
Further reading
-
- Microbiology and Infectious Disease
Flaviviruses, including Zika virus (ZIKV), are a significant global health concern, yet no licensed antivirals exist to treat disease. The small membrane (M) protein plays well-defined roles during viral egress and remains within virion membranes following release and maturation. However, it is unclear whether M plays a functional role in this setting. Here, we show that M forms oligomeric membrane-permeabilising channels in vitro, with increased activity at acidic pH and sensitivity to the prototypic channel-blocker, rimantadine. Accordingly, rimantadine blocked an early stage of ZIKV cell culture infection. Structure-based channel models, comprising hexameric arrangements of two trans-membrane domain protomers were shown to comprise more stable assemblages than other oligomers using molecular dynamics simulations. Models contained a predicted lumenal rimantadine-binding site, as well as a second druggable target region on the membrane-exposed periphery. In silico screening enriched for repurposed drugs/compounds predicted to bind to either one site or the other. Hits displayed superior potency in vitro and in cell culture compared with rimantadine, with efficacy demonstrably linked to virion-resident channels. Finally, rimantadine effectively blocked ZIKV viraemia in preclinical models, supporting that M constitutes a physiologically relevant target. This could be explored by repurposing rimantadine, or development of new M-targeted therapies.
-
- Microbiology and Infectious Disease
Peptidoglycan (PG) is a giant macromolecule that completely surrounds bacterial cells and prevents lysis in hypo-osmotic environments. This net-like macromolecule is made of glycan strands linked to each other by two types of transpeptidases that form either 4→3 (PBPs) or 3→3 (LDTs) cross-links. Previously, we devised a heavy isotope-based PG full labeling method coupled to mass spectrometry to determine the mode of insertion of new subunits into the expanding PG network (Atze et al., 2022). We showed that PG polymerization operates according to different modes for the formation of the septum and of the lateral cell walls, as well as for bacterial growth in the presence or absence of β-lactams in engineered strains that can exclusively rely on LDTs for PG cross-linking when drugs are present. Here, we apply our method to the resolution of the kinetics of the reactions leading to the covalent tethering of the Braun lipoprotein (Lpp) to PG and the subsequent hydrolysis of that same covalent link. We find that Lpp and disaccharide-peptide subunits are independently incorporated into the expanding lateral cell walls. Newly synthesized septum PG appears to contain small amounts of tethered Lpp. LDTs did mediate intense shuffling of Lpp between PG stems leading to a dynamic equilibrium between the PG-tethered and free forms of Lpp.
