BACKGROUND: The canonical Wnt signaling pathway controls the continuous renewal of the intestinal epithelium and the specification of epithelial cell lineages. Tcf4, a nuclear mediator of Wnt signaling, is essential for the differentiation and maintenance of Paneth cells in the small intestine. Its deficiency is associated with reduced expression of key α-defensins, highlighting its role in host-microbe interactions. However, the exact function of Tcf4 in specifying the secretory lineage and its contribution to antimicrobial peptide production remain incompletely understood. Remarkably, α-defensin expression has also been detected in human colon adenomas, where aberrant Wnt signaling is a hallmark. This raises important questions: What is the role of these Paneth-like cells in tumor biology, and how does Tcf4 influence their identity and function? METHODS: We investigated cell specification in small intestinal crypts and colon tumors using conditional Tcf7l2 deletion, cell type-specific Cre recombinases, and reporter alleles in mice. Transcriptomic (single-cell and bulk RNA sequencing) and histological analyses were performed and complemented by microbiome profiling, antibiotic treatment, and intestinal organoids to functionally validate the main findings. RESULTS: The inactivation of Tcf4 depletes Paneth cells and antimicrobial peptides, disrupting the gut microbiota balance. In secretory progenitors, loss of Tcf4 shifts differentiation toward goblet cells. In the small intestine, alternative secretory progenitors produce Wnt ligands to support stem cells and epithelial renewal in the absence of Paneth cells. In colon tumors, Paneth-like cells form a tumor cell population, express Wnt ligands, and require Tcf4 for their identity. Loss of Tcf4 redirects their differentiation toward goblet cells. CONCLUSIONS: Tcf4 controls the balance between Paneth and goblet cells and is essential for antimicrobial peptide production in the small intestine. In colon adenomas, Paneth-like tumor cells drive antimicrobial gene expression and provide Wnt3 ligands, which may have implications for cancer therapy.
- MeSH
- alpha-Defensins metabolism MeSH
- Cell Differentiation MeSH
- Humans MeSH
- Mice MeSH
- Colonic Neoplasms * pathology genetics microbiology metabolism MeSH
- Organoids metabolism MeSH
- Paneth Cells metabolism MeSH
- Goblet Cells metabolism MeSH
- Wnt Signaling Pathway MeSH
- Gastrointestinal Microbiome * MeSH
- Intestine, Small * metabolism pathology microbiology MeSH
- Transcription Factor 4 * metabolism genetics MeSH
- Transcriptome * MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
UNLABELLED: Lyme disease, caused by spirochetes in the Borrelia burgdorferi sensu lato clade within the Borrelia genus, is transmitted by Ixodes ticks and is currently the most prevalent and rapidly expanding tick-borne disease in Europe and North America. We report complete genome sequences of 47 isolates that encompass all established species in this clade while highlighting the diversity of the widespread human pathogenic species B. burgdorferi. A similar set of plasmids has been maintained throughout Borrelia divergence, indicating that they are a key adaptive feature of this genus. Phylogenetic reconstruction of all sequenced Borrelia genomes revealed the original divergence of Eurasian and North American lineages and subsequent dispersals that introduced B. garinii, B. bavariensis, B. lusitaniae, B. valaisiana, and B. afzelii from East Asia to Europe and B. burgdorferi and B. finlandensis from North America to Europe. Molecular phylogenies of the universally present core replicons (chromosome and cp26 and lp54 plasmids) are highly consistent, revealing a strong clonal structure. Nonetheless, numerous inconsistencies between the genome and gene phylogenies indicate species dispersal, genetic exchanges, and rapid sequence evolution at plasmid-borne loci, including key host-interacting lipoprotein genes. While localized recombination occurs uniformly on the main chromosome at a rate comparable to mutation, lipoprotein-encoding loci are recombination hotspots on the plasmids, suggesting adaptive maintenance of recombinant alleles at loci directly interacting with the host. We conclude that within- and between-species recombination facilitates adaptive sequence evolution of host-interacting lipoprotein loci and contributes to human virulence despite a genome-wide clonal structure of its natural populations. IMPORTANCE: Lyme disease (also called Lyme borreliosis in Europe), a condition caused by spirochete bacteria of the genus Borrelia, transmitted by hard-bodied Ixodes ticks, is currently the most prevalent and rapidly expanding tick-borne disease in the United States and Europe. Borrelia interspecies and intraspecies genome comparisons of Lyme disease-related bacteria are essential to reconstruct their evolutionary origins, track epidemiological spread, identify molecular mechanisms of human pathogenicity, and design molecular and ecological approaches to disease prevention, diagnosis, and treatment. These Lyme disease-associated bacteria harbor complex genomes that encode many genes that do not have homologs in other organisms and are distributed across multiple linear and circular plasmids. The functional significance of most of the plasmid-borne genes and the multipartite genome organization itself remains unknown. Here we sequenced, assembled, and analyzed whole genomes of 47 Borrelia isolates from around the world, including multiple isolates of the human pathogenic species. Our analysis elucidates the evolutionary origins, historical migration, and sources of genomic variability of these clinically important pathogens. We have developed web-based software tools (BorreliaBase.org) to facilitate dissemination and continued comparative analysis of Borrelia genomes to identify determinants of human pathogenicity.
- MeSH
- Borrelia burgdorferi Group genetics classification MeSH
- Borrelia burgdorferi genetics classification MeSH
- Borrelia genetics classification MeSH
- Phylogeny * MeSH
- Genetic Variation MeSH
- Genome, Bacterial * MeSH
- Host Microbial Interactions genetics MeSH
- Ixodes microbiology MeSH
- Humans MeSH
- Lipoproteins * genetics MeSH
- Lyme Disease * microbiology transmission MeSH
- Evolution, Molecular MeSH
- Plasmids genetics MeSH
- Recombination, Genetic * MeSH
- Whole Genome Sequencing MeSH
- Selection, Genetic * MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Geographicals
- Europe MeSH
- North America MeSH
The ability of the gut microbiome to adapt to a new environment and utilize a new metabolite or dietary compound by inducing structural variations (SVs) in the genome has an important role in human health. Here, we discuss recent data on host genetic regulation of SV induction and its use as a new therapeutic approach.
BACKGROUND: The gut microbiome is integral to host health, hosting complex interactions between the host and numerous microbial species in the gastrointestinal tract. Key among the molecular mechanisms employed by gut bacteria are transportomes, consisting of diverse transport proteins crucial for bacterial adaptation to the dynamic, nutrient-rich environment of the mammalian gut. These transportomes facilitate the movement of a wide array of molecules, impacting both the host and the microbial community. SUMMARY: This communication explores the significance of transportomes in gut bacteria, focusing on their role in nutrient acquisition, competitive interactions among microbes, and potential pathogenicity. It delves into the transportomes of key gut bacterial species like E. coli, Salmonella, Bacteroides, Lactobacillus, Clostridia, and Bifidobacterium, examining the functions of predicted transport proteins. The overview synthesizes recent research efforts, highlighting how these transportomes influence host-microbe interactions and contribute to the microbial ecology of the gut. KEY MESSAGES: Transportomes are vital for the survival and adaptation of bacteria in the gut, enabling the import and export of various nutrients and molecules. The complex interplay of transport proteins not only supports bacterial growth and competition but also has implications for host health, potentially contributing to pathogenic processes. Understanding the pathogenic potential of transportomes in major gut bacterial species provides insights into gut health and disease, offering avenues for future research and therapeutic strategies.
- MeSH
- Bacteria * metabolism pathogenicity MeSH
- Bacterial Proteins metabolism MeSH
- Biological Transport MeSH
- Gastrointestinal Tract microbiology MeSH
- Host Microbial Interactions physiology MeSH
- Humans MeSH
- Gastrointestinal Microbiome * physiology MeSH
- Carrier Proteins metabolism MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Review MeSH
Iron, as an essential micronutrient, plays a crucial role in host-pathogen interactions. In order to limit the growth of the pathogen, a common strategy of innate immunity includes withdrawing available iron to interfere with the cellular processes of the microorganism. Against that, unicellular parasites have developed powerful strategies to scavenge iron, despite the effort of the host. Iron-sequestering compounds, such as the approved and potent chelator deferoxamine (DFO), are considered a viable option for therapeutic intervention. Since iron is heavily utilized in the mitochondrion, targeting iron chelators in this organelle could constitute an effective therapeutic strategy. This work presents mitochondrially targeted DFO, mitoDFO, as a candidate against a range of unicellular parasites with promising in vitro efficiency. Intracellular Leishmania infection can be cleared by this compound, and experimentation with Trypanosoma brucei 427 elucidates its possible mode of action. The compound not only affects iron homeostasis but also alters the physiochemical properties of the inner mitochondrial membrane, resulting in a loss of function. Furthermore, investigating the virulence factors of pathogenic yeasts confirms that mitoDFO is a viable candidate for therapeutic intervention against a wide spectrum of microbe-associated diseases.
Extracelulární vezikuly (EV) jsou transportní váčky derivované ze zdrojové buňky do extracelulárního prostředí. Představují nový pilíř mezibuněčné komunikace, neboť přenáší nukleové kyseliny, proteiny a různé signální molekuly, které jsou chráněny před degradací v extracelulárním prostředí a posléze jsou uvolněny fúzí vezikuly s cílovou buňkou. Transportní mechanismus je zajištěn povrchovými strukturami účastnícími se buněčné adheze. Je všeobecně známé, že všechny buněčné organismy jsou schopné tvořit EV. Většina lidských buněk je schopna produkovat EV, díky tomu je možná jejich detekce ve všech tělesných kompartmentech. EV při svém objevu byly vnímány jako nepotřebné odpadní váčky a stály na okraji zájmů. Zásluhou nově popsaným mechanismům transportu biologicky aktivních molekul je známo, že se EV účastní celé řady homeostatických mechanismů. V infekčním lékařství je nejvíce studována oblast modulace imunitní odpovědi, kdy jsou vnímány jako potenciální biomarkery, neboť jejich produkce či nesený obsah může být alterován za patologických stavů. U mikrobů stojí v popředí interakce na úrovni patogen-patogen a patogen-hostitel. Další možností je potenciální využití EV jako transportních lékových systémů a nových cílů farmakoterapie.
Extracellular vesicles (EVs) are mother cell derived transport units released into the extracellular environment. They are a new pillar of intercellular communication as they carry nucleic acids, proteins, and other signalling molecules, protecting them from degradation in the extracellular environment until fusion of the vesicle with the target cell. The transport mechanism relies on surface structures involved in cell adhesion. It is well known that all cellular organisms are capable of producing EVs. Most human cells have this capability, and EVs can be detected in all body compartments. At the time of their discovery, EVs were considered as useless waste vesicles of marginal interest. Thanks to the newly described transport mechanisms of biologically active molecules, EVs are currently known to participate in a variety of homeostatic mechanisms. In infectious diseases, the most studied area is the modulation of the immune response, where they are seen as potential biomarkers, as their production or the content they carry can be altered under pathological conditions. For microbes, interactions at the pathogen-pathogen and pathogen-host level are at the forefront of attention. EVs also have potential for use as drug delivery systems and novel targets for pharmacotherapy.
- MeSH
- Biomarkers metabolism MeSH
- Exosomes classification microbiology MeSH
- Extracellular Vesicles * physiology classification microbiology MeSH
- Bacterial Physiological Phenomena MeSH
- Virus Physiological Phenomena MeSH
- Cell Communication genetics MeSH
- Transport Vesicles physiology classification microbiology MeSH
- Publication type
- Research Support, Non-U.S. Gov't MeSH
- Review MeSH
Previous studies indicated an intrinsic relationship between infant diet, intestinal microbiota composition and fermentation activity with a strong focus on the role of breastfeeding on microbiota composition. Yet, microbially formed short-chain fatty acids acetate, propionate and butyrate and other fermentation metabolites such as lactate not only act as substrate for bacterial cross-feeding and as mediators in microbe-host interactions but also confer antimicrobial activity, which has received considerably less attention in the past research. It was the aim of this study to investigate the nutritional-microbial interactions that contribute to the development of infant gut microbiota with a focus on human milk oligosaccharide (HMO) fermentation. Infant fecal microbiota composition, fermentation metabolites and milk composition were analyzed from 69 mother-infant pairs of the Swiss birth cohort Childhood AlleRgy nutrition and Environment (CARE) at three time points depending on breastfeeding status defined at the age of 4 months, using quantitative microbiota profiling, HPLC-RI and 1H-NMR. We conducted in vitro fermentations in the presence of HMO fermentation metabolites and determined the antimicrobial activity of lactate and acetate against major Clostridiaceae and Peptostreptococcaceae representatives. Our data show that fucosyllactose represented 90% of the HMOs present in breast milk at 1- and 3-months post-partum with fecal accumulation of fucose, 1,2-propanediol and lactate indicating fermentation of HMOs that is likely driven by Bifidobacterium. Concurrently, there was a significantly lower absolute abundance of Peptostreptococcaceae in feces of exclusively breastfed infants at 3 months. In vitro, lactate inhibited strains of Peptostreptococcaceae. Taken together, this study not only identified breastfeeding dependent fecal microbiota and metabolite profiles but suggests that HMO-derived fermentation metabolites might exert an inhibitory effect against selected gut microbes.
- Publication type
- Journal Article MeSH
- Keywords
- fágoterapie,
- MeSH
- Tumor Virus Infections MeSH
- Host Microbial Interactions MeSH
- Humans MeSH
- Oncogenic Viruses MeSH
- Virus Diseases * MeSH
- Viruses * MeSH
- Check Tag
- Humans MeSH
- Publication type
- Review MeSH
- MeSH
- Single-Cell Analysis MeSH
- Bacteria * MeSH
- Host Microbial Interactions * MeSH
- Publication type
- Editorial MeSH
Francisella tularensis is a highly infectious Gram-negative coccobacillus which causes the disease tularemia. The potential for its misuse as a biological weapon has led disease control and prevention centers to classify this bacterium as a category A agent. Bacterial outer membrane vesicles (OMVs) are spherical particles 20-250 nm in size produced by all Gram-negative bacteria and constitute one of the major secretory pathways. Bacteria use them in interacting with both other bacterial cells and eukaryotic (host) cells. OMVs of Francisella contain number of its so far described virulence factors and immunomodulatory proteins. Their role in host-pathogen interactions can therefore be presumed, and the possibility exists also for their potential use in a subunit vaccine. Moreover, Francisella microbes produce both usual spherical and unusual tubular OMVs. Because OMVs emerge from the outermost surface of the bacterial cell, we focused on the secretion of OMVs in several mutant Francisella strains with disrupted surface structures (namely the O-antigen). O-antigen in Francisella is not only the structural component of LPS but also forms another important virulence factor: the O-antigen polysaccharide capsule. Mutant strain phenotypes were evaluated by growth curves, vesiculation rates, their sensitivity to the complement contained in serum, and proliferation inside murine bone marrow macrophages. Morphologies of both OMVs and the bacteria were visualized by electron microscopy. The O-antigen mutant strains were considerably attenuated in serum resistance and intracellular proliferation. All the strains showed lower ability to form the tubular OMVs. Some strains formed tubular protrusions from their outer membrane but their stability was weak. Some hypervesiculating strains were revealed that will serve as source of OMVs for further studies of their protective potential. Our results suggest the presence of LPS and the O-antigen capsule on the surface of Francisella to be critical not only for its virulence but also for the exceptional tubular shape of its OMVs.
- MeSH
- Francisella tularensis * genetics MeSH
- Gram-Negative Bacteria MeSH
- Lipopolysaccharides chemistry MeSH
- Mice MeSH
- O Antigens MeSH
- Bacterial Outer Membrane Proteins genetics metabolism MeSH
- Tularemia * microbiology prevention & control MeSH
- Animals MeSH
- Check Tag
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
