Other search tools

About this data

The publication data currently available has been vetted by Vanderbilt faculty, staff, administrators and trainees. The data itself is retrieved directly from NCBI's PubMed and is automatically updated on a weekly basis to ensure accuracy and completeness.

If you have any questions or comments, please contact us.

Results: 1 to 10 of 691

Publication Record

Connections

infection damages colonic stem cells via TcdB, impairing epithelial repair and recovery from disease.
Mileto SJ, Jardé T, Childress KO, Jensen JL, Rogers AP, Kerr G, Hutton ML, Sheedlo MJ, Bloch SC, Shupe JA, Horvay K, Flores T, Engel R, Wilkins S, McMurrick PJ, Lacy DB, Abud HE, Lyras D
(2020) Proc Natl Acad Sci U S A 117: 8064-8073
MeSH Terms: Animals, Bacterial Proteins, Bacterial Toxins, Cells, Cultured, Clostridium Infections, Clostridium difficile, Colon, Disease Models, Animal, Female, Frizzled Receptors, Humans, Intestinal Mucosa, Mice, Organoids, Primary Cell Culture, Recombinant Proteins, Stem Cells
Show Abstract · Added March 24, 2020
Gastrointestinal infections often induce epithelial damage that must be repaired for optimal gut function. While intestinal stem cells are critical for this regeneration process [R. C. van der Wath, B. S. Gardiner, A. W. Burgess, D. W. Smith, 8, e73204 (2013); S. Kozar , 13, 626-633 (2013)], how they are impacted by enteric infections remains poorly defined. Here, we investigate infection-mediated damage to the colonic stem cell compartment and how this affects epithelial repair and recovery from infection. Using the pathogen we show that infection disrupts murine intestinal cellular organization and integrity deep into the epithelium, to expose the otherwise protected stem cell compartment, in a TcdB-mediated process. Exposure and susceptibility of colonic stem cells to intoxication compromises their function during infection, which diminishes their ability to repair the injured epithelium, shown by altered stem cell signaling and a reduction in the growth of colonic organoids from stem cells isolated from infected mice. We also show, using both mouse and human colonic organoids, that TcdB from epidemic ribotype 027 strains does not require Frizzled 1/2/7 binding to elicit this dysfunctional stem cell state. This stem cell dysfunction induces a significant delay in recovery and repair of the intestinal epithelium of up to 2 wk post the infection peak. Our results uncover a mechanism by which an enteric pathogen subverts repair processes by targeting stem cells during infection and preventing epithelial regeneration, which prolongs epithelial barrier impairment and creates an environment in which disease recurrence is likely.
0 Communities
1 Members
0 Resources
17 MeSH Terms
Intestinal bile acids directly modulate the structure and function of TcdB toxin.
Tam J, Icho S, Utama E, Orrell KE, Gómez-Biagi RF, Theriot CM, Kroh HK, Rutherford SA, Lacy DB, Melnyk RA
(2020) Proc Natl Acad Sci U S A 117: 6792-6800
MeSH Terms: Bacterial Toxins, Bile Acids and Salts, Caco-2 Cells, Clostridium Infections, Clostridium difficile, HCT116 Cells, Humans, Intestines, Receptors, Cell Surface
Show Abstract · Added March 24, 2020
Intestinal bile acids are known to modulate the germination and growth of Here we describe a role for intestinal bile acids in directly binding and neutralizing TcdB toxin, the primary determinant of disease. We show that individual primary and secondary bile acids reversibly bind and inhibit TcdB to varying degrees through a mechanism that requires the combined oligopeptide repeats region to which no function has previously been ascribed. We find that bile acids induce TcdB into a compact "balled up" conformation that is no longer able to bind cell surface receptors. Lastly, through a high-throughput screen designed to identify bile acid mimetics we uncovered nonsteroidal small molecule scaffolds that bind and inhibit TcdB through a bile acid-like mechanism. In addition to suggesting a role for bile acids in pathogenesis, these findings provide a framework for development of a mechanistic class of antitoxins.
0 Communities
1 Members
0 Resources
9 MeSH Terms
Structural elucidation of the transferase toxin reveals a single-site binding mode for the enzyme.
Sheedlo MJ, Anderson DM, Thomas AK, Lacy DB
(2020) Proc Natl Acad Sci U S A 117: 6139-6144
MeSH Terms: Bacterial Toxins, Clostridium difficile, Cryoelectron Microscopy, Enterotoxins, Protein Conformation, beta-Strand, Protein Multimerization, Transferases
Show Abstract · Added March 24, 2020
is a Gram-positive, pathogenic bacterium and a prominent cause of hospital-acquired diarrhea in the United States. The symptoms of infection are caused by the activity of three large toxins known as toxin A (TcdA), toxin B (TcdB), and the transferase toxin (CDT). Reported here is a 3.8-Å cryo-electron microscopy (cryo-EM) structure of CDT, a bipartite toxin comprised of the proteins CDTa and CDTb. We observe a single molecule of CDTa bound to a CDTb heptamer. The formation of the CDT complex relies on the interaction of an N-terminal adaptor and pseudoenzyme domain of CDTa with six subunits of the CDTb heptamer. CDTb is observed in a preinsertion state, a conformation observed in the transition of prepore to β-barrel pore, although we also observe a single bound CDTa in the prepore and β-barrel conformations of CDTb. The binding interaction appears to prime CDTa for translocation as the adaptor subdomain enters the lumen of the preinsertion state channel. These structural observations advance the understanding of how a single protein, CDTb, can mediate the delivery of a large enzyme, CDTa, into the cytosol of mammalian cells.
0 Communities
1 Members
0 Resources
7 MeSH Terms
exhibits heterogeneous siderophore production within the vertebrate host.
Perry WJ, Spraggins JM, Sheldon JR, Grunenwald CM, Heinrichs DE, Cassat JE, Skaar EP, Caprioli RM
(2019) Proc Natl Acad Sci U S A 116: 21980-21982
MeSH Terms: Abscess, Animals, Citrates, Host-Pathogen Interactions, Iron, Mice, Ornithine, Siderophores, Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization, Staphylococcal Infections, Staphylococcus aureus
Show Abstract · Added January 22, 2020
Siderophores, iron-scavenging small molecules, are fundamental to bacterial nutrient metal acquisition and enable pathogens to overcome challenges imposed by nutritional immunity. Multimodal imaging mass spectrometry allows visualization of host-pathogen iron competition, by mapping siderophores within infected tissue. We have observed heterogeneous distributions of siderophores across infectious foci, challenging the paradigm that the vertebrate host is a uniformly iron-depleted environment to invading microbes.
Copyright © 2019 the Author(s). Published by PNAS.
0 Communities
3 Members
0 Resources
11 MeSH Terms
IL-10-producing B cells are enriched in murine pericardial adipose tissues and ameliorate the outcome of acute myocardial infarction.
Wu L, Dalal R, Cao CD, Postoak JL, Yang G, Zhang Q, Wang Z, Lal H, Van Kaer L
(2019) Proc Natl Acad Sci U S A 116: 21673-21684
MeSH Terms: Adipose Tissue, Animals, B-Lymphocytes, Chemokine CXCL13, Female, Inflammation, Interleukin-10, Interleukin-33, Lymphocyte Count, Male, Mice, Mice, Inbred C57BL, Mice, Knockout, Myocardial Infarction, Pericardium, Regeneration
Show Abstract · Added March 3, 2020
Acute myocardial infarction (MI) provokes an inflammatory response in the heart that removes damaged tissues to facilitate tissue repair/regeneration. However, overactive and prolonged inflammation compromises healing, which may be counteracted by antiinflammatory mechanisms. A key regulatory factor in an inflammatory response is the antiinflammatory cytokine IL-10, which can be produced by a number of immune cells, including subsets of B lymphocytes. Here, we investigated IL-10-producing B cells in pericardial adipose tissues (PATs) and their role in the healing process following acute MI in mice. We found that IL-10-producing B cells were enriched in PATs compared to other adipose depots throughout the body, with the majority of them bearing a surface phenotype consistent with CD5 B-1a cells (CD5 B cells). These cells were detected early in life, maintained a steady presence during adulthood, and resided in fat-associated lymphoid clusters. The cytokine IL-33 and the chemokine CXCL13 were preferentially expressed in PATs and contributed to the enrichment of IL-10-producing CD5 B cells. Following acute MI, the pool of CD5 B cells was expanded in PATs. These cells accumulated in the infarcted heart during the resolution of MI-induced inflammation. B cell-specific deletion of IL-10 worsened cardiac function, exacerbated myocardial injury, and delayed resolution of inflammation following acute MI. These results revealed enrichment of IL-10-producing B cells in PATs and a significant contribution of these cells to the antiinflammatory processes that terminate MI-induced inflammation. Together, these findings have identified IL-10-producing B cells as therapeutic targets to improve the outcome of MI.
0 Communities
1 Members
0 Resources
16 MeSH Terms
Targeted mobilization of Lrig1 gastric epithelial stem cell populations by a carcinogenic type IV secretion system.
Wroblewski LE, Choi E, Petersen C, Delgado AG, Piazuelo MB, Romero-Gallo J, Lantz TL, Zavros Y, Coffey RJ, Goldenring JR, Zemper AE, Peek RM
(2019) Proc Natl Acad Sci U S A 116: 19652-19658
MeSH Terms: Adenocarcinoma, Animals, Carcinogenesis, Disease Models, Animal, Epithelial Cells, Female, Gastric Mucosa, Gastritis, Helicobacter Infections, Helicobacter pylori, Humans, Male, Membrane Glycoproteins, Mice, Mice, Knockout, Nerve Tissue Proteins, Precancerous Conditions, Primary Cell Culture, Risk Factors, Stem Cells, Stomach, Stomach Neoplasms, Type IV Secretion Systems
Show Abstract · Added September 27, 2019
-induced gastritis is the strongest risk factor for gastric adenocarcinoma, a malignancy preceded by a series of well-defined histological stages, including metaplasia. One microbial constituent that augments cancer risk is the type 4 secretion system (T4SS), which translocates the oncoprotein CagA into host cells. Aberrant stem cell activation is linked to carcinogenesis, and Lrig1 (leucine-rich repeats and Ig-like domains 1) marks a distinct population of progenitor cells. We investigated whether microbial effectors with carcinogenic potential influence Lrig1 progenitor cells ex vivo and via lineage expansion within -infected gastric mucosa. Lineage tracing was induced in (Lrig1/YFP) mice that were uninfected or subsequently infected with or an isogenic mutant (nonfunctional T4SS). In contrast to infection with wild-type (WT) for 2 wk, infection for 8 wk resulted in significantly increased inflammation and proliferation in the corpus and antrum compared with uninfected or mice infected with the mutant. WT -infected mice harbored significantly higher numbers of Lrig1/YFP epithelial cells that coexpressed UEA1 (surface cell marker). The number of cells coexpressing intrinsic factor (chief cell marker), YFP (lineage marker), and GSII lectin (spasmolytic polypeptide-expressing metaplasia marker) were increased only by WT In human samples, Lrig1 expression was significantly increased in lesions with premalignant potential compared with normal mucosa or nonatrophic gastritis. In conclusion, chronic infection stimulates Lrig1-expressing progenitor cells in a -dependent manner, and these reprogrammed cells give rise to a full spectrum of differentiated cells.
1 Communities
1 Members
0 Resources
23 MeSH Terms
Unknown actor in adipose tissue metabolism hiding in plain sight.
Collins S
(2019) Proc Natl Acad Sci U S A 116: 17145-17146
MeSH Terms: Adipose Tissue, Thermogenesis
Added July 22, 2020
0 Communities
1 Members
0 Resources
MeSH Terms
White matter volume and white/gray matter ratio in mammalian species as a consequence of the universal scaling of cortical folding.
Mota B, Dos Santos SE, Ventura-Antunes L, Jardim-Messeder D, Neves K, Kazu RS, Noctor S, Lambert K, Bertelsen MF, Manger PR, Sherwood CC, Kaas JH, Herculano-Houzel S
(2019) Proc Natl Acad Sci U S A 116: 15253-15261
MeSH Terms: Animals, Artiodactyla, Cerebral Cortex, Connectome, Gray Matter, Humans, Neurons, Organ Size, Organ Specificity, Primates, Rodentia, Scandentia, White Matter
Show Abstract · Added March 30, 2020
Because the white matter of the cerebral cortex contains axons that connect distant neurons in the cortical gray matter, the relationship between the volumes of the 2 cortical compartments is key for information transmission in the brain. It has been suggested that the volume of the white matter scales universally as a function of the volume of the gray matter across mammalian species, as would be expected if a global principle of wiring minimization applied. Using a systematic analysis across several mammalian clades, here we show that the volume of the white matter does not scale universally with the volume of the gray matter across mammals and is not optimized for wiring minimization. Instead, the ratio between volumes of gray and white matter is universally predicted by the same equation that predicts the degree of folding of the cerebral cortex, given the clade-specific scaling of cortical thickness, such that the volume of the gray matter (or the ratio of gray to total cortical volumes) divided by the square root of cortical thickness is a universal function of total cortical volume, regardless of the number of cortical neurons. Thus, the very mechanism that we propose to generate cortical folding also results in compactness of the white matter to a predictable degree across a wide variety of mammalian species.
0 Communities
1 Members
0 Resources
MeSH Terms
Hypoxia-inducible factors in CD4 T cells promote metabolism, switch cytokine secretion, and T cell help in humoral immunity.
Cho SH, Raybuck AL, Blagih J, Kemboi E, Haase VH, Jones RG, Boothby MR
(2019) Proc Natl Acad Sci U S A 116: 8975-8984
MeSH Terms: Animals, Antibody Formation, B-Lymphocytes, Basic Helix-Loop-Helix Transcription Factors, CD4-Positive T-Lymphocytes, Cell Hypoxia, Cytokines, Germinal Center, Humans, Hypoxia, Hypoxia-Inducible Factor 1, alpha Subunit, Immunity, Humoral, Immunization, Lymphocyte Activation, Mice, Mice, Inbred C57BL, Mice, Transgenic, Receptors, CXCR5, Sheep, T-Lymphocytes, Helper-Inducer
Show Abstract · Added April 23, 2019
T cell help in humoral immunity includes interactions of B cells with activated extrafollicular CD4 and follicular T helper (Tfh) cells. Each can promote antibody responses but Tfh cells play critical roles during germinal center (GC) reactions. After restimulation of their antigen receptor (TCR) by B cells, helper T cells act on B cells via CD40 ligand and secreted cytokines that guide Ig class switching. Hypoxia is a normal feature of GC, raising questions about molecular mechanisms governing the relationship between hypoxia response mechanisms and T cell help to antibody responses. Hypoxia-inducible factors (HIF) are prominent among mechanisms that mediate cellular responses to limited oxygen but also are induced by lymphocyte activation. We now show that loss of HIF-1α or of both HIF-1α and HIF-2α in CD4 T cells compromised essential functions in help during antibody responses. HIF-1α depletion from CD4 T cells reduced frequencies of antigen-specific GC B cells, Tfh cells, and overall antigen-specific Ab after immunization with sheep red blood cells. Compound deficiency of HIF-1α and HIF-2α led to humoral defects after hapten-carrier immunization. Further, HIF promoted CD40L expression while restraining the FoxP3-positive CD4 cells in the CXCR5 follicular regulatory population. Glycolysis increases T helper cytokine expression, and HIF promoted glycolysis in T helper cells via TCR or cytokine stimulation, as well as their production of cytokines that direct antibody class switching. Indeed, IFN-γ elaboration by HIF-deficient in vivo-generated Tfh cells was impaired. Collectively, the results indicate that HIF transcription factors are vital components of the mechanisms of help during humoral responses.
0 Communities
1 Members
0 Resources
20 MeSH Terms
Energetic regulation of coordinated leader-follower dynamics during collective invasion of breast cancer cells.
Zhang J, Goliwas KF, Wang W, Taufalele PV, Bordeleau F, Reinhart-King CA
(2019) Proc Natl Acad Sci U S A 116: 7867-7872
MeSH Terms: Adenosine Diphosphate, Adenosine Triphosphate, Breast Neoplasms, Cell Line, Tumor, Cell Movement, Energy Metabolism, Female, Glucose, Humans, Intracellular Space, Neoplasm Invasiveness
Show Abstract · Added April 10, 2019
The ability of primary tumor cells to invade into adjacent tissues, followed by the formation of local or distant metastasis, is a lethal hallmark of cancer. Recently, locomoting clusters of tumor cells have been identified in numerous cancers and associated with increased invasiveness and metastatic potential. However, how the collective behaviors of cancer cells are coordinated and their contribution to cancer invasion remain unclear. Here we show that collective invasion of breast cancer cells is regulated by the energetic statuses of leader and follower cells. Using a combination of in vitro spheroid and ex vivo organoid invasion models, we found that cancer cells dynamically rearrange leader and follower positions during collective invasion. Cancer cells invade cooperatively in denser collagen matrices by accelerating leader-follower switching thus decreasing leader cell lifetime. Leader cells exhibit higher glucose uptake than follower cells. Moreover, their energy levels, as revealed by the intracellular ATP/ADP ratio, must exceed a threshold to invade. Forward invasion of the leader cell gradually depletes its available energy, eventually leading to leader-follower transition. Our computational model based on intracellular energy homeostasis successfully recapitulated the dependence of leader cell lifetime on collagen density. Experiments further supported model predictions that decreasing the cellular energy level by glucose starvation decreases leader cell lifetime whereas increasing the cellular energy level by AMP-activated kinase (AMPK) activation does the opposite. These findings highlight coordinated invasion and its metabolic regulation as potential therapeutic targets of cancer.
0 Communities
1 Members
0 Resources
11 MeSH Terms