SUMMARY Herpes simplex virus 1 (HSV-1), a leading cause of genital herpes, infects oral or genital mucosal epithelial cells before infecting the peripheral sensory nervous system. The spread of HSV-1 beyond the sensory nervous system and the resulting broader spectrum of disease are not well understood. Using a mouse model of genital herpes, we found that HSV-1-infection-associated lethality correlated with severe fecal and urinary retention. No inflammation or infection of the brain was evident. Instead, HSV-1 spread via the dorsal root ganglia to the autonomic ganglia of the enteric nervous system (ENS) in the colon. ENS infection led to robust viral gene transcription, pathological inflammatory responses, and neutrophil-mediated destruction of enteric neurons, ultimately resulting in permanent loss of peristalsis and the development of toxic megacolon. Laxative treatment rescued mice from lethality following genital HSV-1 infection. These results reveal an unexpected pathogenesis of HSV associated with ENS infection.

The canonical Gα subunit of the heterotrimeric G protein complex from wheat (Triticum aestivum), GA3, and the calcium-binding protein, Clo3, were revealed to interact both in vivo and in vitro and Clo3 was shown to enhance the GTPase activity of GA3. Clo3 is a member of the caleosin gene family in wheat with a single EF-hand domain and is induced during cold acclimation. Bimolecular Fluorescent Complementation (BiFC) was used to localize the interaction between Clo3 and GA3 to the plasma membrane (PM). Even though heterotrimeric G-protein signaling and Ca²⁺ signaling have both been shown to play a role in the response to environmental stresses in plants, little is known about the interaction between calcium-binding proteins and Gα. The GAP activity of Clo3 towards GA3 suggests it may play a role in the inactivation of GA3 as part of the stress response in plants. GA3 was also shown to interact with the phosphoinositide-specific phospholipase C, PI-PLC1, not only in the PM but also in the endoplasmic reticulum (ER). Surprisingly, Clo3 was also shown to interact with PI-PLC1 in the PM and ER. In vitro analysis of the protein-protein interaction showed that the interaction of Clo3 with GA3 and PI-PLC1 is enhanced by high Ca²⁺ levels. Three-way affinity characterizations with GA3, Clo3 and PI-PLC1 showed the interaction with Clo3 to be competitive, which suggests that Clo3 may play a role in the Ca²⁺-triggered feedback regulation of both GA3 and PI-PLC1. This hypothesis was further supported by the demonstration that Clo3 has GAP activity with GA3.

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POMC neurons integrate metabolic signals from the periphery. Here, we show in mice that food deprivation induces a linear current-voltage relationship of AMPAR-mediated excitatory postsynaptic currents (EPSCs) in POMC neurons. Inhibition of EPSCs by IEM-1460, an antagonist of calcium-permeable (Cp) AMPARs, diminished EPSC amplitude in the fed but not in the fasted state, suggesting entry of GluR2 subunits into the AMPA receptor complex during food deprivation. Accordingly, removal of extracellular calcium from ACSF decreased the amplitude of mEPSCs in the fed but not the fasted state. Ten days of high-fat diet exposure, which was accompanied by elevated leptin levels and increased POMC neuronal activity, resulted in increased expression of Cp-AMPARs on POMC neurons. Altogether, our results show that entry of calcium via Cp-AMPARs is inherent to activation of POMC neurons, which may underlie a vulnerability of these neurons to calcium overload while activated in a sustained manner during over-nutrition.DOI: http://dx.doi.org/10.7554/eLife.25755.001

ObiectiveBowel movement frequency (BMF) variation has been linked to changes in the composition of the human gut microbiome and to many chronic conditions, like metabolic disorders, neurodegenerative diseases, chronic kidney disease (CKD), and other intestinal pathologies like irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD). Slow intestinal transit times (constipation) are thought to lead to compromised intestinal barrier integrity and a switch from saccharolytic to proteolytic fermentation within the microbiota, giving rise to microbially-derived toxins that may make their way into circulation and cause damage to organ systems. However, these phenomena have not been characterized in generally-healthy populations, and the connections between microbial metabolism and the early-stage development and progression of chronic disease remain underexplored.DesignHere, we examine the phenotypic impact of BMF variation across a cohort of over 2,000 generally-healthy, community dwelling adults with detailed clinical, lifestyle, and multi-omic data.ResultsWe show significant differences in key blood plasma metabolites, proteins, chemistries, gut bacterial genera, and lifestyle factors across BMF groups that have been linked, in particular, to inflammation and CKD severity and progression.DiscussionIn addition to dissecting BMF-related heterogeneity in blood metabolites, proteins, and the gut microbiome, we identify self-reported diet, lifestyle, and psychological factors associated with BMF variation, which suggest several potential strategies for mitigating constipation and diarrhea. Overall, this work highlights the potential for managing BMF to prevent disease.What is already known about this topicConstipation and diarrhea are linked to several chronic diseases, like IBD, CKD, and neurodegenerative disorders. Chronic constipation, in particular, is associated with the increased production of microbially-derived uremic toxins in the gut due to an ecosystem-wide switch from fiber fermentation to protein fermentation. A build-up of these gut-derived toxins in blood, like p-cresol, has been associated with CKD disease progression and severity.What this study addsWhile prior work has demonstrated associations between microbially-derived uremic toxins, constipation, and CKD severity/progression, here we show similar signatures in a generally-healthy cohort. Overall, we map out the molecular phenotypic effects of aberrant BMFs across individuals without any apparent disease, and show how these effects precede, and may contribute to, the development of chronic disease. We find that certain lifestyle and dietary patterns, like higher levels of exercise, reduced anxiety levels, a more plant-based diet, and drinking more water, are associated with a more optimal BMF range.How this study might affect research, policy, or practiceOverall, we suggest that even mild levels of chronic constipation may cause damage to organ systems over time and ultimately give rise to chronic diseases, like CKD or neurodegeneration. These findings pave the way for future research into early interventions for individuals at risk of developing chronic diseases related to BMF abnormalities. Managing BMF abnormalities prior to disease development may be an important disease prevention strategy, but this will require further evidence through longitudinal human intervention trials.