Phylogenetically diverse bacterial species produce histamine.

Histamine is an important biogenic amine known to impact a variety of patho-physiological processes ranging from allergic reactions, gut-mediated anti-inflammatory responses, and neurotransmitter activity. Histamine is found both endogenously within specialized host cells and exogenously in microbes. Exogenous histamine is produced through the decarboxylation of the amino acid L-histidine by bacterial-derived histidine decarboxylase enzymes.

Purinergic Signaling Drives Multiple Aspects of Rotavirus Pathophysiology.

Rotavirus causes life-threatening diarrhea in children, resulting in ∼200,000 deaths/year. The current treatment during infection is Oral Rehydration Solution which successfully replenishes fluids but does not alleviate diarrhea volume or severity. As a result, there is an urgent need to better understand rotavirus pathophysiology and develop more effective pediatric therapeutics.

Viroporin activity from rotavirus nonstructural protein 4 induces intercellular calcium waves that contribute to pathogenesis.

Acute gastroenteritis remains the second leading cause of death among children under the age of 5 worldwide. While enteric viruses are the most common etiology, the drivers of their virulence remain incompletely understood. We recently found that cells infected with rotavirus, the most prevalent enteric virus in infants and young children, initiate hundreds of intercellular calcium waves that enhance both fluid secretion and viral spread.

Live Calcium Imaging of Virus-Infected Human Intestinal Organoid Monolayers Using Genetically Encoded Calcium Indicators.

Calcium signaling is an integral regulator of nearly every tissue. Within the intestinal epithelium, calcium is involved in the regulation of secretory activity, actin dynamics, inflammatory responses, stem cell proliferation, and many other uncharacterized cellular functions. As such, mapping calcium signaling dynamics within the intestinal epithelium can provide insight into homeostatic cellular processes and unveil unique responses to various stimuli.

Live-Cell Fluorescence Imaging for Virus-Host Interactions.

Recent technological advances in microscopy have facilitated novel approaches to investigate host-pathogen interactions. In particular, improvements in both microscope hardware and engineered biosensors have helped to overcome barriers to live-cell imaging with fluorescence microscopy. Live fluorescent microscopy allows for the detection of discrete signaling events and protein localization, improving our ability to assess the effects of pharmacologic agents, microbes, or infection with high temporal resolution.

Host IPR channels are dispensable for rotavirus Ca signaling but critical for intercellular Ca waves that prime uninfected cells for rapid virus spread.

Many viruses exploit host Ca signaling to facilitate their replication; however, little is known about how Ca signals from different host and viral channels contribute to the overall dysregulation of Ca signaling or promote virus replication. Using cells lacking IPR, a host ER Ca channel, we delineated intracellular Ca signals within virus-infected cells and intercellular Ca waves (ICWs), which increased Ca signaling in neighboring, uninfected cells. In infected cells, IPR was dispensable for rotavirus-induced Ca signaling and replication, suggesting the rotavirus NSP4 viroporin supplies these signals.

Distribution of P2Y and P2X purinergic receptor expression within the intestine.

Nucleotides are potent extracellular signaling molecules during homeostasis, infection, and injury due to their ability to activate purinergic receptors. The nucleotide ATP activates P2X receptors (P2RXs), whereas the nucleotides ADP, ATP, UTP, and UDP-glucose selectively activate different P2Y receptors (P2RYs). Several studies have established crucial roles for P2 receptors during intestinal inflammatory and infectious diseases, yet the most extensive characterization of purinergic signaling has focused on immune cells and the central and enteric nervous systems.

A high-throughput protocol for measuring solution pH of bacterial cultures using UV-Vis absorption spectrophotometry.

We present a protocol for measuring the pH of cell-free bacterial-conditioned media based on changes in the ultraviolet-visible (UV-Vis) absorbance spectrum using the pH indicator dye litmus. This protocol includes detailed procedures for performing bacterial culturing, examining bacterial growth, collecting cell-free supernatant, litmus dye addition, and pH-based calibration curve preparations. This assay has been designed for flexible formatting that can accommodate both high-volume and low-volume sample sets.

The Inositol Trisphosphate Receptor (IP R) is Dispensable for Rotavirus-induced Ca Signaling and Replication but Critical for Paracrine Ca Signals that Prime Uninfected Cells for Rapid Virus Spread.

Unlabelled: Rotavirus is a leading cause of viral gastroenteritis. A hallmark of rotavirus infection is an increase in cytosolic Ca caused by the nonstructural protein 4 (NSP4). NSP4 is a viral ion channel that releases Ca from the endoplasmic reticulum (ER) and the increase in Ca signaling is critical for rotavirus replication.

Bioinformatics reveal elevated levels of Myosin Vb in uterine corpus endometrial carcinoma patients which correlates to increased cell metabolism and poor prognosis.

Carcinoma of the endometrium of the uterus is the most common female pelvic malignancy. Although uterine corpus endometrial cancer (UCEC) has a favorable prognosis if removed early, patients with advanced tumor stages have a low survival rate. These facts highlight the importance of understanding UCEC biology.

Gastrointestinal organoids in the study of viral infections.

Viruses are among the most prevalent enteric pathogens. Although virologists historically relied on cell lines and animal models, human intestinal organoids (HIOs) continue to grow in popularity. HIOs are nontransformed, stem cell-derived, ex vivo cell cultures that maintain the cell type diversity of the intestinal epithelium.

Myosin 5b is required for proper localization of the intermicrovillar adhesion complex in the intestinal brush border.

Intestinal enterocytes have an elaborate apical membrane of actin-rich protrusions known as microvilli. The organization of microvilli is orchestrated by the intermicrovillar adhesion complex (IMAC), which connects the distal tips of adjacent microvilli. The IMAC is composed of CDHR2 and CDHR5 as well as the scaffolding proteins USH1C, ANKS4B, and Myosin 7b (MYO7B).

Neurotransmitter Profiles Are Altered in the Gut and Brain of Mice Mono-Associated with .

Background: Accumulating evidence indicates that the gut microbiota can synthesize neurotransmitters as well as impact host-derived neurotransmitter levels. In the past, it has been challenging to decipher which microbes influence neurotransmitters due to the complexity of the gut microbiota.

Methods: To address whether a single microbe, could regulate important neurotransmitters, we examined genomes and explored neurotransmitter pathways in secreted cell-free supernatant using LC-MS/MS.

The metabolic profile of Bifidobacterium dentium reflects its status as a human gut commensal.

Background: Bifidobacteria are commensal microbes of the mammalian gastrointestinal tract. In this study, we aimed to identify the intestinal colonization mechanisms and key metabolic pathways implemented by Bifidobacterium dentium.

Results: B.

-derived y-glutamylcysteine suppresses ER-mediated goblet cell stress and reduces TNBS-driven colonic inflammation.

Endoplasmic reticulum (ER) stress compromises the secretion of MUC2 from goblet cells and has been linked with inflammatory bowel disease (IBD). Although can beneficially modulate mucin production, little work has been done investigating the effects of on goblet cell ER stress. We hypothesized that secreted factors from downregulate ER stress genes and modulates the unfolded protein response (UPR) to promote MUC2 secretion.

Secretes Outer Membrane Vesicles and Promotes Intestinal Inflammation.

Multiple studies have implicated microbes in the development of inflammation, but the mechanisms remain unknown. Bacteria in the genus have been identified in the intestinal mucosa of patients with digestive diseases; thus, we hypothesized that promotes intestinal inflammation. The addition of >50 kDa conditioned media, which contain outer membrane vesicles (OMVs), to colonic epithelial cells stimulated secretion of the proinflammatory cytokines interleukin-8 (IL-8) and tumor necrosis factor (TNF).

Bacteroides ovatus Promotes IL-22 Production and Reduces Trinitrobenzene Sulfonic Acid-Driven Colonic Inflammation.

The intestinal microbiota influences the development and function of the mucosal immune system. However, the exact mechanisms by which commensal microbes modulate immunity is not clear. We previously demonstrated that commensal Bacteroides ovatus ATCC 8384 reduces mucosal inflammation.

Immunomodulation of dendritic cells by Lactobacillus reuteri surface components and metabolites.

Background: Lactic acid bacteria are commensal members of the gut microbiota and are postulated to promote host health. Secreted factors and cell surface components from Lactobacillus species have been shown to modulate the host immune system. However, the precise role of L.

Rotavirus induces intercellular calcium waves through ADP signaling.

Rotavirus causes severe diarrheal disease in children by broadly dysregulating intestinal homeostasis. However, the underlying mechanism(s) of rotavirus-induced dysregulation remains unclear. We found that rotavirus-infected cells produce paracrine signals that manifested as intercellular calcium waves (ICWs), observed in cell lines and human intestinal enteroids.

Mucin-Degrading Microbes Release Monosaccharides That Chemoattract and Facilitate Colonization of the Human Intestinal Mucus Layer.

It is widely accepted that the pathogen exploits an intestinal environment with an altered microbiota, but the details of these microbe-microbe interactions are unclear. Adherence and colonization of mucus has been demonstrated for several enteric pathogens and it is possible that mucin-associated microbes may be working in concert with . We showed that ribotype-027 adheres to MUC2 glycans and using fecal bioreactors, we identified that associates with several mucin-degrading microbes.

Extracting Insights From Temporal Data by Integrating Dynamic Modeling and Machine Learning.

Biological processes are dynamic. As a result, temporal analyses are necessary to fully understand the complex interactions that occurs within these systems. One example of a multifaceted biological process is restitution: the initial step in complex wound repair.

Enhancing responsiveness of human jejunal enteroids to host and microbial stimuli.

Key Points: Enteroids are a physiologically relevant model to examine the human intestine and its functions. Previously, the measurable cytokine response of human intestinal enteroids has been limited following exposure to host or microbial pro-inflammatory stimuli. Modifications to enteroid culture conditions facilitated robust human cytokine responses to pro-inflammatory stimuli.

Human intestinal enteroids as a model of -induced enteritis.

is an important nosocomial pathogen that produces toxins to cause life-threatening diarrhea and colitis. Toxins bind to epithelial receptors and promote the collapse of the actin cytoskeleton. toxin activity is commonly studied in cancer-derived and immortalized cell lines.