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Microbe-host interactions in the intestine occur along the mucus-covered epithelium. In the gastrointestinal tract, mucus is composed of glycan-covered proteins, or mucins, which are secreted by goblet cells to form a protective gel-like structure above the epithelium. Low levels of mucin or alterations in mucin glycans are associated with inflammation and colitis in mice and humans. Although current literature links microbes to the modulation of goblet cells and mucins, the molecular pathways involved are not yet fully understood. Using a combination of gnotobiotic mice and mucus-secreting cell lines, we have identified a human-derived microbe, Bifidobacterium dentium , which adheres to intestinal mucus and secretes metabolites that upregulate the major mucin MUC2 and modulate goblet cell function. Unlike other Bifidobacterium species, B. dentium does not extensively degrade mucin glycans and cannot grow on mucin alone. This work points to the potential of using B. dentium and similar mucin-friendly microbes as therapeutic agents for intestinal disorders with disruptions in the mucus barrier. Much remains unknown about how the intestinal microbiome interfaces with the protective intestinal mucus layer. Bifidobacterium species colonize the intestinal mucus layer and can modulate mucus production by goblet cells. However, select Bifidobacterium strains can also degrade protective glycans on mucin proteins. We hypothesized that the human-derived species Bifidobacterium dentium would increase intestinal mucus synthesis and expulsion, without extensive degradation of mucin glycans. In silico data revealed that B. dentium lacked the enzymes necessary to extensively degrade mucin glycans. This finding was confirmed by demonstrating that B. dentium could not use naive mucin glycans as primary carbon sources in vitro . To examine B. dentium mucus modulation in vivo , Swiss Webster germfree mice were monoassociated with live or heat-killed B. dentium . Live B. dentium -monoassociated mice exhibited increased colonic expression of goblet cell markers Krüppel-like factor 4 ( Klf4 ), Trefoil factor 3 ( Tff3 ), Relm -β, Muc2 , and several glycosyltransferases compared to both heat-killed B. dentium and germfree counterparts. Likewise, live B. dentium -monoassociated colon had increased acidic mucin-filled goblet cells, as denoted by Periodic Acid-Schiff-Alcian Blue (PAS-AB) staining and MUC2 immunostaining. In vitro , B. dentium -secreted products, including acetate, were able to increase MUC2 levels in T84 cells. We also identified that B. dentium -secreted products, such as γ-aminobutyric acid (GABA), stimulated autophagy-mediated calcium signaling and MUC2 release. This work illustrates that B. dentium is capable of enhancing the intestinal mucus layer and goblet cell function via upregulation of gene expression and autophagy signaling pathways, with a net increase in mucin production. IMPORTANCE Microbe-host interactions in the intestine occur along the mucus-covered epithelium. In the gastrointestinal tract, mucus is composed of glycan-covered proteins, or mucins, which are secreted by goblet cells to form a protective gel-like structure above the epithelium. Low levels of mucin or alterations in mucin glycans are associated with inflammation and colitis in mice and humans. Although current literature links microbes to the modulation of goblet cells and mucins, the molecular pathways involved are not yet fully understood. Using a combination of gnotobiotic mice and mucus-secreting cell lines, we have identified a human-derived microbe, Bifidobacterium dentium , which adheres to intestinal mucus and secretes metabolites that upregulate the major mucin MUC2 and modulate goblet cell function. Unlike other Bifidobacterium species, B. dentium does not extensively degrade mucin glycans and cannot grow on mucin alone. This work points to the potential of using B. dentium and similar mucin-friendly microbes as therapeutic agents for intestinal disorders with disruptions in the mucus barrier.

Several studies have identified an increased abundance of Fusobacterium in the intestinal tracts of patients with colon cancer, liver cirrhosis, primary sclerosing cholangitis, gastroesophageal reflux disease, HIV infection, and alcoholism. However, the direct mechanism(s) of action of Fusobacterium on pathophysiological within the gastrointestinal tract is unclear. Multiple studies have implicated microbes in the development of inflammation, but the mechanisms remain unknown. Bacteria in the genus Fusobacterium have been identified in the intestinal mucosa of patients with digestive diseases; thus, we hypothesized that Fusobacterium nucleatum promotes intestinal inflammation. The addition of >50 kDa F. nucleatum 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). In addition, purified F. nucleatum OMVs, but not compounds <50 kDa, stimulated IL-8 and TNF production; which was decreased by pharmacological inhibition of Toll-like receptor 4 (TLR4). These effects were linked to downstream effectors p-ERK, p-CREB, and NF-κB. F. nucleatum >50-kDa compounds also stimulated TNF secretion, p-ERK, p-CREB, and NF-κB activation in human colonoid monolayers. In mice harboring a human microbiota, pretreatment with antibiotics and a single oral gavage of F. nucleatum resulted in inflammation. Compared to mice receiving vehicle control, mice treated with F. nucleatum showed disruption of the colonic architecture, with increased immune cell infiltration and depleted mucus layers. Analysis of mucosal gene expression revealed increased levels of proinflammatory cytokines (KC, TNF, IL-6, IFN-γ, and MCP-1) at day 3 and day 5 in F. nucleatum -treated mice compared to controls. These proinflammatory effects were absent in mice who received F. nucleatum without pretreatment with antibiotics, suggesting that an intact microbiome is protective against F. nucleatum -mediated immune responses. These data provide evidence that F. nucleatum promotes proinflammatory signaling cascade s in the context of a depleted intestinal microbiome. IMPORTANCE Several studies have identified an increased abundance of Fusobacterium in the intestinal tracts of patients with colon cancer, liver cirrhosis, primary sclerosing cholangitis, gastroesophageal reflux disease, HIV infection, and alcoholism. However, the direct mechanism(s) of action of Fusobacterium on pathophysiological within the gastrointestinal tract is unclear. These studies have identified that F. nucleatum subsp. polymorphum releases outer membrane vesicles which activate TLR4 and NF-κB to stimulate proinflammatory signals in vitro . Using mice harboring a human microbiome, we demonstrate that F. nucleatum can promote inflammation, an effect which required antibiotic-mediated alterations in the gut microbiome. Collectively, these results suggest a mechanism by which F. nucleatum may contribute to intestinal inflammation.

Like many viruses, rotavirus (RV) dysregulates calcium homeostasis by elevating cytosolic calcium ([Ca 2+ ]cyt) and decreasing endoplasmic reticulum (ER) stores. While an overall, monophasic increase in [Ca 2+ ]cyt during RV infection has been shown, the nature of the RV-induced aberrant calcium signals and how they manifest over time at the single-cell level have not been characterized. Thus, we generated cell lines and human intestinal enteroids (HIEs) stably expressing cytosolic and/or ER-targeted genetically-encoded calcium indicators to characterize calcium signaling throughout RV infection by time-lapse imaging. We found that RV induces highly dynamic [Ca 2+ ]cyt signaling that manifest as hundreds of discrete [Ca 2+ ]cyt spikes, which increase during peak infection. Knockdown of nonstructural protein 4 (NSP4) attenuates the [Ca 2+ ]cyt spikes, consistent with its role in dysregulating calcium homeostasis. RV-induced [Ca 2+ ]cyt spikes were primarily from ER calcium release and were attenuated by inhibiting the store-operated calcium entry (SOCE) channel Orai1. RV-infected HIEs also exhibited prominent [Ca 2+ ]cyt spikes that were attenuated by inhibiting SOCE, underlining the relevance of these [Ca 2+ ]cyt spikes to gastrointestinal physiology and role of SOCE in RV pathophysiology. Thus, our discovery that RV increases [Ca 2+ ]cyt by dynamic calcium signaling, establishes a new, paradigm-shifting understanding of the spatial and temporal complexity of virus-induced calcium signaling.

The Loma Linda University Medical Center Institutional Review Board approved this study (IRB #5170335). Though burnout has not yet been directly correlated with HRV metrics, the use of wearable devices to measure HRV may provide physiologic correlates to better predict burnout or to rate the success of different interventions for physician wellness.Declaration of competing interest The clinical research lab of Dr. Ramsingh received two wrist-worn photoplethysmographic devices with corresponding battery charger from Wavelet Health (Mountain View, CA, United States), which were used to carry out this research. Variables Baseline Call shift Post-call period Interbeat interval (ms) 66.0 ± 42.0 50.8 ± 30.3 54.1 ± 33.6 SDNN (ms) 57.2 ± 39.8 50.8 ± 24.9 57.4 ± 28.6 RMSSD (ms) 67.3 ± 31.2 58.4 ± 26.5 70.0 ± 32.6 LFnu 43.0 ± 21.8 40.0 ± 16.0 31.5 ± 10.1 HFnu 31.9 ± 20.4 27.8 ± 11.2 23.2 ± 6.7 LF/HF 2.1 ± 2.0 1.7 ± 1.1 1.5 ± 0.6 Table 1 Summary of captured variables and comparisons of heart rate variability during call shift and post-call periods.

Tulane virus is one of many enteric caliciviruses that cause acute gastroenteritis and diarrheal disease. Globally, enteric caliciviruses affect both humans and animals and amass >65 billion dollars per year in treatment and health care-associated costs, thus imposing an enormous economic burden. Recent progress has resulted in several cultivation systems (B cells, enteroids, and zebrafish larvae) to study human noroviruses, but mechanistic insights into the viral factors and host pathways important for enteric calicivirus replication and infection are still largely lacking. Here, we used Tulane virus, a calicivirus that is biologically similar to human noroviruses and can be cultivated by conventional cell culture, to identify and functionally validate NS1-2 as an enteric calicivirus viroporin. Viroporin-mediated calcium signaling may be a broadly utilized pathway for enteric virus replication, and its existence within caliciviruses provides a novel approach to developing antivirals and comprehensive therapeutics for enteric calicivirus diarrheal disease outbreaks. Enteric viruses in the Caliciviridae family cause acute gastroenteritis in humans and animals, but the cellular processes needed for virus replication and disease remain unknown. A common strategy among enteric viruses, including rotaviruses and enteroviruses, is to encode a viral ion channel (i.e., viroporin) that is targeted to the endoplasmic reticulum (ER) and disrupts host calcium (Ca 2+ ) homeostasis. Previous reports have demonstrated genetic and functional similarities between the nonstructural proteins of caliciviruses and enteroviruses, including the calicivirus NS1-2 protein and the 2B viroporin of enteroviruses. However, it is unknown whether caliciviruses alter Ca 2+ homeostasis for virus replication or whether the NS1-2 protein has viroporin activity like its enterovirus counterpart. To address these questions, we used Tulane virus (TV), a rhesus enteric calicivirus, to examine Ca 2+ signaling during infection and determine whether NS1-2 has viroporin activity that disrupts Ca 2+ homeostasis. We found that TV increases Ca 2+ signaling during infection and that increased cytoplasmic Ca 2+ levels are important for efficient replication. Further, TV NS1-2 localizes to the endoplasmic reticulum, the predominant intracellular Ca 2+ store, and the NS2 region has characteristics of a viroporin domain (VPD). NS1-2 had viroporin activity in a classic bacterial functional assay and caused aberrant Ca 2+ signaling when expressed in mammalian cells, but truncation of the VPD abrogated these activities. Together, our data provide new mechanistic insights into the function of the NS2 region of NS1-2 and support the premise that enteric viruses, including those within Caliciviridae , exploit host Ca 2+ signaling to facilitate their replication. IMPORTANCE Tulane virus is one of many enteric caliciviruses that cause acute gastroenteritis and diarrheal disease. Globally, enteric caliciviruses affect both humans and animals and amass >65 billion dollars per year in treatment and health care-associated costs, thus imposing an enormous economic burden. Recent progress has resulted in several cultivation systems (B cells, enteroids, and zebrafish larvae) to study human noroviruses, but mechanistic insights into the viral factors and host pathways important for enteric calicivirus replication and infection are still largely lacking. Here, we used Tulane virus, a calicivirus that is biologically similar to human noroviruses and can be cultivated by conventional cell culture, to identify and functionally validate NS1-2 as an enteric calicivirus viroporin. Viroporin-mediated calcium signaling may be a broadly utilized pathway for enteric virus replication, and its existence within caliciviruses provides a novel approach to developing antivirals and comprehensive therapeutics for enteric calicivirus diarrheal disease outbreaks.

Neuromyelitis optica (NMO) is a rare demyelinating disorder affecting the spinal cord and optic nerves. Like multiple sclerosis (MS), it predominantly affects women during childbearing years. The impact of neuraxial anesthesia on the course of NMO is uncertain. There are no large studies available to draw definitive conclusions regarding the safety of neuraxial anesthesia in this population. A review of the current literature suggests that neuraxial anesthesia is unlikely to exacerbate neurologic symptoms in pregnant patients with NMO. However, given the rarity of this disease entity among patients requesting epidural labor analgesia, we recommend taking a cautious approach.

The cars and crumbling buildings, increasingly being renovated into photo-ops and bed and breakfasts for a burgeoning tourist trade, are evidence of a place caught in the legacy of a decades-old cold war embargo, preventing the flow of goods and monies yet at the same time experiencing an increased ease in international travel, including most recently with its US neighbor, just a 90-minute plane ride to the north. The images convey both the faded glamour of the 1950s and the long history of Cuba through the effects of cold war politics, layered onto the histories of the Chinese family associations and diasporic communities that appear through Lau's images of the last Chinese-language newspaper, Diario Popular Chino, and the forgotten porticos in the Barrio Chino. Alexandra Chang is Associate Professor of Practice, Art, Culture, and Media at the Clement A. Price Institute on Ethnicity, Culture, and the Modern Experience at Rutgers University, Newark.