Defining the role of Hmu and Hus systems in Porphyromonas gingivalis heme and iron homeostasis and virulence.

Iron and heme are essential nutrients for all branches of life. Pathogenic members of the Bacteroidota phylum, including Porphyromonas gingivalis, do not synthesize heme and rely on host hemoproteins for heme as a source of iron and protoporphyrin IX. P.

HmuY differentially participates in heme acquisition compared to the and hemophore-like proteins.

Introduction: and belong to the Bacteroidota phylum. Both species inhabit the oral cavity and can be associated with periodontal diseases. To survive, they must uptake heme from the host as an iron and protoporphyrin IX source.

Hemophore-like proteins of the HmuY family in the oral and gut microbiome: unraveling the mystery of their evolution.

Heme (iron protoporphyrin IX, FePPIX) is the main source of iron and PPIX for host-associated pathogenic bacteria, including members of the Bacteroidota (formerly Bacteroidetes) phylum. , a keystone oral pathogen, uses a unique heme uptake (Hmu) system, comprising a hemophore-like protein, designated as the first member of the novel HmuY family. Compared to classical, secreted hemophores utilized by Gram-negative bacteria or near-iron transporter domain-based hemophores utilized by Gram-positive bacteria, the HmuY family comprises structurally similar proteins that have undergone diversification during evolution.

Comparative analysis of A7436 and ATCC 33277 strains reveals differences in the expression of heme acquisition systems.

Unlabelled: strains exhibit different phenotypes , different virulence potential in animal models, and different associations with human diseases, with strains classified as virulent/more virulent (e.g., A7436 and W83) or as less virulent/avirulent (e.

Bacteroides fragilis expresses three proteins similar to Porphyromonas gingivalis HmuY: Hemophore-like proteins differentially evolved to participate in heme acquisition in oral and gut microbiomes.

Oral and gut microbiomes are important for the maintenance of homeostasis in the human body. Altered or disturbed mutualism between their members results in dysbiosis with local injury and subsequent systemic diseases. The high bacterial density causes intense competition among microbiome residents to acquire nutrients, including iron and heme, the latter of high importance for heme auxotrophic members of the Bacteroidetes phylum.

Hemophore-like proteins produced by periodontopathogens are recognized by the host immune system and react differentially with IgG antibodies.

Aims: Hemophore-like proteins sequester heme from host hemoproteins. We aimed to determine whether the host immune system can recognize not only HmuY but also its homologs expressed by other periodontopathogens, and how periodontitis influences the production of respective antibodies.

Methods: The reactivity of total bacterial antigens and purified proteins with serum IgG antibodies of 18 individuals with periodontitis and 17 individuals without periodontitis was examined by enzyme-linked immunosorbent assay (ELISA).

Interplay between Porphyromonas gingivalis Hemophore-Like Protein HmuY and Kgp/RgpA Gingipains Plays a Superior Role in Heme Supply.

To acquire heme as a source of iron and protoporphyrin IX, Porphyromonas gingivalis uses gingipains, Hmu, and Hus systems. The aim of this study was to assess the correlation between the production and function of the most important virulence factors of P. gingivalis involved in heme supply, namely, hemophore-like proteins (HmuY and HusA) and gingipains.

Glycation of Host Proteins Increases Pathogenic Potential of .

The non-enzymatic addition of glucose (glycation) to circulatory and tissue proteins is a ubiquitous pathophysiological consequence of hyperglycemia in diabetes. Given the high incidence of periodontitis and diabetes and the emerging link between these conditions, it is of crucial importance to define the basic virulence mechanisms employed by periodontopathogens such as in mediating the disease process. The aim of this study was to determine whether glycated proteins are more easily utilized by to stimulate growth and promote the pathogenic potential of this bacterium.

HmuY and Bvu-A Novel Competitive Heme Acquisition Strategy.

Human oral and gut microbiomes are crucial for maintenance of homeostasis in the human body. , the key etiologic agent of chronic periodontitis, can cause dysbiosis in the mouth and gut, which results in local and systemic infectious inflammatory diseases. Our previous work resulted in extensive biochemical and functional characterization of one of the major heme acquisition systems (Hmu), with the leading role played by the HmuY hemophore-like protein.

HmuY and GAPDH-Novel Heme Acquisition Strategy in the Oral Microbiome.

The oral cavity of healthy individuals is inhabited by commensals, with species of being the most abundant and prevalent in sites not affected by periodontal diseases. The development of chronic periodontitis is linked with the environmental shift in the oral microbiome, leading to the domination of periodontopathogens. Structure-function studies showed that employs a "moonlighting" protein glyceraldehyde-3-phosphate dehydrogenase (SgGAPDH) to bind heme, thus forming a heme reservoir for exchange with other proteins.

Prevotella intermedia produces two proteins homologous to Porphyromonas gingivalis HmuY but with different heme coordination mode.

As part of the infective process, Porphyromonas gingivalis must acquire heme which is indispensable for life and enables the microorganism to survive and multiply at the infection site. This oral pathogenic bacterium uses a newly discovered novel hmu heme uptake system with a leading role played by the HmuY hemophore-like protein, responsible for acquiring heme and increasing virulence of this periodontopathogen. We demonstrated that Prevotella intermedia produces two HmuY homologs, termed PinO and PinA.

PgRsp Is a Novel Redox-Sensing Transcription Regulator Essential for Virulence.

is one of the etiological agents of chronic periodontitis. Both heme and oxidative stress impact expression of genes responsible for its survival and virulence. Previously we showed that ferric uptake regulator homolog affects expression of a gene encoding a putative Crp/Fnr superfamily member, termed redox-sensing protein (PgRsp).

PgFur Is a Member of a Novel Fur Subfamily With Non-canonical Function.

, a keystone pathogen of chronic periodontitis, uses ferric uptake regulator homolog (PgFur) to regulate production of virulence factors. This study aimed to characterize PgFur protein in regard to its structure-function relationship. We experimentally identified the 5' mRNA sequence encoding the 171-amino-acid-long PgFur protein in the A7436 strain and examined this PgFur version as a full-length protein.

PgFur participates differentially in expression of virulence factors in more virulent A7436 and less virulent ATCC 33277 Porphyromonas gingivalis strains.

Background: Porphyromonas gingivalis is considered a keystone pathogen responsible for chronic periodontitis. Although several virulence factors produced by this bacterium are quite well characterized, very little is known about regulatory mechanisms that allow different strains of P. gingivalis to efficiently survive in the hostile environment of the oral cavity, a typical habitat characterized by low iron and heme concentrations.

Tfo belongs to HmuY-like family of proteins but differs in heme-binding properties.

is considered the principal etiologic agent and keystone pathogen of chronic periodontitis. As an auxotrophic bacterium, it must acquire heme to survive and multiply at the infection site. HmuY is the first member of a novel family of hemophore-like proteins.

Antimicrobial activity of stable hemiaminals against Porphyromonas gingivalis.

Porphyromonas gingivalis is a major etiologic agent and a key pathogen responsible for the development and progression of chronic periodontitis. Controlling the number of periodontal pathogens is one of the primary actions for maintaining oral health; therefore, active compounds with a capacity to exert antimicrobial activity have received considerable attention as they may represent potential new therapeutic agents for the treatment of chronic periodontitis. Heterocyclic compounds possessing 1,2,4- or 1,2,3-triazoles are known for several biological activities, including antibacterial properties.

In Vivo Cleavage Map Illuminates the Central Role of RNase E in Coding and Non-coding RNA Pathways.

Understanding RNA processing and turnover requires knowledge of cleavages by major endoribonucleases within a living cell. We have employed TIER-seq (transiently inactivating an endoribonuclease followed by RNA-seq) to profile cleavage products of the essential endoribonuclease RNase E in Salmonella enterica. A dominating cleavage signature is the location of a uridine two nucleotides downstream in a single-stranded segment, which we rationalize structurally as a key recognition determinant that may favor RNase E catalysis.

Anti-HmuY antibodies specifically recognize Porphyromonas gingivalis HmuY protein but not homologous proteins in other periodontopathogens.

Given the emerging evidence of an association between periodontal infections and systemic conditions, the search for specific methods to detect the presence of P. gingivalis, a principal etiologic agent in chronic periodontitis, is of high importance. The aim of this study was to characterize antibodies raised against purified P.