Transient Receptor Potential Ankyrin-1-expressing vagus nerve fibers mediate IL-1β induced hypothermia and reflex anti-inflammatory responses

Cytokines reprogram airway sensory neurons in asthma

Nociceptor neurons play a crucial role in maintaining the body's homeostasis by detecting and responding to potential environmental dangers. However, this function can be detrimental during allergic reactions, as vagal nociceptors contribute to immune cell infiltration, bronchial hypersensitivity, and mucus imbalance in addition to causing pain and coughing. Despite this, the specific mechanisms by which nociceptors acquire pro-inflammatory characteristics during allergic reactions are not yet fully understood. In this study, we investigate the changes in the molecular profile of airway nociceptor neurons during allergic airway inflammation and identify the signals driving such reprogramming. Using retrograde tracing and lineage reporting, we identify a specific class of inflammatory vagal nociceptor neurons that exclusively innervate the airways. In the ovalbumin mouse model of allergic airway inflammation, these neurons undergo significant reprogramming characterized by the upregulation of the neuropeptide Y (NPY) receptor Npy1r. A screening of cytokines and neurotrophins reveals that interleukin 1β (IL-1β), IL-13, and brain-derived neurotrophic factor (BDNF) drive part of this reprogramming. IL-13 triggers Npy1r overexpression in nociceptors via the JAK/STAT6 pathway. In parallel, NPY is released into the bronchoalveolar fluid of asthmatic mice, which limits the excitability of nociceptor neurons. Single-cell RNA sequencing of lung immune cells reveals that a cell-specific knockout of NPY1R in nociceptor neurons in asthmatic mice altered T cell infiltration. Opposite findings are observed in asthmatic mice in which nociceptor neurons are chemically ablated. In summary, allergic airway inflammation reprograms airway nociceptor neurons to acquire a pro-inflammatory phenotype, while a compensatory mechanism involving NPY1R limits the activity of nociceptor neurons.

Lipopolysaccharide-mediated effects of the microbiota on sleep and body temperature

Recent research suggests that microbial molecules translocated from the intestinal lumen into the host's internal environment may play a role in various physiological functions, including sleep. Previously, we identified that butyrate, a short-chain fatty acid produced by intestinal bacteria, and lipoteichoic acid, a cell wall component of gram-positive bacteria, induce sleep when their naturally occurring translocation is mimicked by direct delivery into the portal vein. Building upon these findings, we aimed to explore the sleep signaling potential of intraportally administered lipopolysaccharide (LPS), a primary component of gram-negative bacterial cell walls, in rats. Low dose of LPS (1 μg/kg) increased sleep duration and prolonged fever, without affecting systemic LPS levels. Interestingly, administering LPS systemically outside the portal region at a dose 20 times higher did not affect sleep, indicating a localized sensitivity within the hepatoportal region for the sleep and febrile effects of LPS. Furthermore, both the sleep- and fever-inducing effects of LPS were inhibited by indomethacin, a prostaglandin synthesis inhibitor, and replicated by intraportal administration of prostaglandin E2 or arachidonic acid, suggesting the involvement of the prostaglandin system in mediating these actions.

Cytokines reprogram airway sensory neurons in asthma

Nociceptor neurons play a crucial role in maintaining the body's homeostasis by detecting and responding to potential dangers in the environment. However, this function can be detrimental during allergic reactions, since vagal nociceptors can contribute to immune cell infiltration, bronchial hypersensitivity, and mucus imbalance, in addition to causing pain and coughing. Despite this, the specific mechanisms by which nociceptors acquire pro-inflammatory characteristics during allergic reactions are not yet fully understood. In this study, we aimed to investigate the molecular profile of airway nociceptor neurons during allergic airway inflammation and identify the signals driving such reprogramming. Using retrograde tracing and lineage reporting, we identified a unique class of inflammatory vagal nociceptor neurons that exclusively innervate the airways. In the ovalbumin mouse model of airway inflammation, these neurons undergo significant reprogramming characterized by the upregulation of the NPY receptor Npy1r. A screening of cytokines and neurotrophins revealed that IL-1β, IL-13 and BDNF drive part of this reprogramming. IL-13 triggered Npy1r overexpression in nociceptors via the JAK/STAT6 pathway. In parallel, sympathetic neurons and macrophages release NPY in the bronchoalveolar fluid of asthmatic mice, which limits the excitability of nociceptor neurons. Single-cell RNA sequencing of lung immune cells has revealed that a cell-specific knockout of Npy1r in nociceptor neurons in asthmatic mice leads to an increase in airway inflammation mediated by T cells. Opposite findings were observed in asthmatic mice in which nociceptor neurons were chemically ablated. In summary, allergic airway inflammation reprograms airway nociceptor neurons to acquire a pro-inflammatory phenotype, while a compensatory mechanism involving NPY1R limits nociceptor neurons' activity.

Unveiling the role of TRPA1 in cardiovascular health and disease: a mini review

The transient receptor potential ankyrin 1 (TRPA1) ion channel has emerged as significant regulators of cardiovascular physiology and pathology. TRPA1 is a non-selective cation channel permeable to calcium ions. A unique feature of the channel is its function as a sensor of various temperature, chemical and mechanical stimuli, while it can also be activated by endogenous inflammatory mediators and reactive oxygen species. Over the last two decades, much progress has been made in illuminating the role of TRPA1 in the regulation of cardiovascular physiology and pathophysiology in addition to its important function in pain sensation. This review provides a comprehensive analysis of recent studies investigating the involvement of TRPA1 channels in various cardiovascular diseases, including myocardial infarction, ischemia-reperfusion injury, myocardial fibrosis, and response to environmental toxins. We discuss the diverse roles of TRPA1 channels in cardiac pathology and highlight their potential as therapeutic targets for cardiovascular disorders. Moreover, we explore the challenges and opportunities linked with targeting TRPA1 channels for treating cardiovascular diseases, alongside future research directions.

ZO-1 and IL-1RAP Phosphorylation: Potential Role in Mediated Brain-Gut Axis Dysregulation in Irritable Bowel Syndrome-like Stressed Mice

Background and Objectives: Irritable Bowel Syndrome (IBS) is a common gastrointestinal disorder often exacerbated by stress, influencing the brain-gut axis (BGA). BGA dysregulation, disrupted intestinal barrier function, altered visceral sensitivity and immune imbalance defects underlying IBS pathogenesis have been emphasized in recent investigations. Phosphoproteomics reveals unique phosphorylation details resulting from environmental stress. Here, we employ phosphoproteomics to explore the molecular mechanisms underlying IBS-like symptoms, mainly focusing on the role of ZO-1 and IL-1RAP phosphorylation. Materials and Methods: Morris water maze (MWM) was used to evaluate memory function for single prolonged stress (SPS). To assess visceral hypersensitivity of IBS-like symptoms, use the Abdominal withdrawal reflex (AWR). Colonic bead expulsion and defecation were used to determine fecal characteristics of the IBS-like symptoms. Then, we applied a phosphoproteomic approach to BGA research to discover the molecular mechanisms underlying the process of visceral hypersensitivity in IBS-like mice following SPS. ZO-1, p-S179-ZO1, IL-1RAP, p-S566-IL-1RAP and GFAP levels in BGA were measured by western blotting, immunofluorescence staining, and enzyme-linked immunosorbent assay to validate phosphorylation quantification. Fluorescein isothiocyanate-dextran 4000 and electron-microscopy were performed to observe the structure and function of the intestinal epithelial barrier. Results: The SPS group showed changes in learning and memory ability. SPS exposure affects visceral hypersensitivity, increased fecal water content, and significant diarrheal symptoms. Phosphoproteomic analysis displayed that p-S179-ZO1 and p-S566-IL-1RAP were significantly differentially expressed following SPS. In addition, p-S179-ZO1 was reduced in mice's DRG, colon, small intestine, spinal and hippocampus and intestinal epithelial permeability was increased. GFAP, IL-1β and p-S566-IL-1RAP were also increased at the same levels in the BGA. And IL-1β showed no significant difference was observed in serum. Our findings reveal substantial alterations in ZO-1 and IL-1RAP phosphorylation, correlating with increased epithelial permeability and immune imbalance. Conclusions: Overall, decreased p-S179-ZO1 and increased p-S566-IL-1RAP on the BGA result in changes to tight junction structure, compromising the structure and function of the intestinal epithelial barrier and exacerbating immune imbalance in IBS-like stressed mice.

A body-brain circuit that regulates body inflammatory responses

The body-brain axis is emerging as a principal conductor of organismal physiology. It senses and controls organ function1,2, metabolism3 and nutritional state4-6. Here we show that a peripheral immune insult strongly activates the body-brain axis to regulate immune responses. We demonstrate that pro-inflammatory and anti-inflammatory cytokines communicate with distinct populations of vagal neurons to inform the brain of an emerging inflammatory response. In turn, the brain tightly modulates the course of the peripheral immune response. Genetic silencing of this body-brain circuit produced unregulated and out-of-control inflammatory responses. By contrast, activating, rather than silencing, this circuit affords neural control of immune responses. We used single-cell RNA sequencing, combined with functional imaging, to identify the circuit components of this neuroimmune axis, and showed that its selective manipulation can effectively suppress the pro-inflammatory response while enhancing an anti-inflammatory state. The brain-evoked transformation of the course of an immune response offers new possibilities in the modulation of a wide range of immune disorders, from autoimmune diseases to cytokine storm and shock.

The Role of TRP Channels in Sepsis and Colitis

To date, several members of the transient receptor potential (TRP) channels which provide a wide array of roles have been found in the gastrointestinal tract (GI). The goal of earlier research was to comprehend the intricate signaling cascades that contribute to TRP channel activation as well as how these receptors' activity affects other systems. Moreover, there is a large volume of published studies describing the role of TRP channels in a number of pathological disorders, including inflammatory bowel disease (IBD) and sepsis. Nevertheless, the generalizability of these results is subject to certain limitations. For instance, the study of IBD relies on various animal models and experimental methods, which are unable to precisely imitate the multifactorial chronic disease. The diverse pathophysiological mechanisms and unique susceptibility of animals may account for the inconsistency of the experimental data collected. The main purpose of this study was to conduct a comprehensive review and analysis of existing studies on transient receptor potential (TRP) channels implicating specific models of colitis and sepsis, with particular emphasis on their involvement in pathological disorders such as IBD and sepsis. Furthermore, the text endeavors to evaluate the generalizability of experimental findings, taking into consideration the limitations posed by animal models and experimental methodologies. Finally, we also provide an updated schematic of the most important and possible molecular signaling pathways associated with TRP channels in IBD and sepsis.

Analysis of predictors of fever after aortic valve replacement: Diabetic patients are less likely to develop fever after aortic valve replacement, a single-centre retrospective study

BACKGROUND

Postoperative temperature dysregulation affects the length of hospital stay and prognosis. This study evaluated the factors that influence the occurrence of fever in patients after aortic valve replacement surgery.

METHODS

Eighty-seven consecutive patients who underwent aortic valve replacement surgery were included. Patients' age, sex and body mass index; presence of diabetes mellitus; operation time; blood loss; blood transfusion volume; preoperative and postoperative laboratory findings; presence or absence of oral function management; and fever >38°C were retrospectively analysed through univariate and multiple logistic regression analyses.

RESULTS

Among the variables, only diabetes mellitus status was significantly associated with fever ⩾38°C. Postoperatively, patients with diabetes mellitus were significantly less likely to develop fever above 38°C and a fever rising to 38°C.

CONCLUSIONS

This study shows that the presence of comorbid diabetes mellitus decreases the frequency of developing fever >38°C after aortic valve replacement surgery.

Lipopolysaccharide-Mediated Effects of the Microbiota on Sleep and Body Temperature

Background

Recent research suggests that microbial molecules translocated from the intestinal lumen into the host's internal environment may play a role in various physiological functions, including sleep. Previously, we identified that butyrate, a short-chain fatty acid, produced by intestinal bacteria, and lipoteichoic acid, a cell wall component of gram-positive bacteria induce sleep when their naturally occurring translocation is mimicked by direct delivery into the portal vein. Building upon these findings, we aimed to explore the sleep signaling potential of intraportally administered lipopolysaccharide, a primary component of gram-negative bacterial cell walls, in rats.

Results

Low dose of lipopolysaccharide (1 μg/kg) increased sleep duration and prolonged fever, without affecting systemic lipopolysaccharide levels. Interestingly, administering LPS systemically outside the portal region at a dose 20 times higher did not affect sleep, indicating a localized sensitivity within the hepatoportal region, encompassing the portal vein and liver, for the sleep and febrile effects of lipopolysaccharide. Furthermore, both the sleep- and fever-inducing effects of LPS were inhibited by indomethacin, a prostaglandin synthesis inhibitor, and replicated by intraportal administration of prostaglandin E2 or arachidonic acid, suggesting the involvement of the prostaglandin system in mediating these actions.

Conclusions

These findings underscore the dynamic influence of lipopolysaccharide in the hepatoportal region on sleep and fever mechanisms, contributing to a complex microbial molecular assembly that orchestrates communication between the intestinal microbiota and brain. Lipopolysaccharide is a physiological component of plasma in both the portal and extra-portal circulation, with its levels rising in response to everyday challenges like high-fat meals, moderate alcohol intake, sleep loss and psychological stress. The increased translocation of lipopolysaccharide under such conditions may account for their physiological impact in daily life, highlighting the intricate interplay between microbial molecules and host physiology.

The Fifth Bioelectronic Medicine Summit: today's tools, tomorrow's therapies

The emerging field of bioelectronic medicine (BEM) is poised to make a significant impact on the treatment of several neurological and inflammatory disorders. With several BEM therapies being recently approved for clinical use and others in late-phase clinical trials, the 2022 BEM summit was a timely scientific meeting convening a wide range of experts to discuss the latest developments in the field. The BEM Summit was held over two days in New York with more than thirty-five invited speakers and panelists comprised of researchers and experts from both academia and industry. The goal of the meeting was to bring international leaders together to discuss advances and cultivate collaborations in this emerging field that incorporates aspects of neuroscience, physiology, molecular medicine, engineering, and technology. This Meeting Report recaps the latest findings discussed at the Meeting and summarizes the main developments in this rapidly advancing interdisciplinary field. Our hope is that this Meeting Report will encourage researchers from academia and industry to push the field forward and generate new multidisciplinary collaborations that will form the basis of new discoveries that we can discuss at the next BEM Summit.

The Effect of Postinduction Blood Glucose on Intraoperative Hypothermia

Background and Objectives: Hypothermia frequently occurs in patients undergoing surgery and is associated with adverse complications. Therefore, this study aimed to investigate the postinduction blood glucose and occurrence of intraoperative hypothermia in patients undergoing laparoscopic surgery. Materials and Methods: This retrospective observational study included 334 patients aged ≥20 years who had undergone elective laparoscopic surgery. The primary outcome of this study was the incidence of intraoperative hypothermia. Stratified analysis revealed differences between patients with and without diabetes. Results: Hypothermia occurred in 200 (59.9%) patients. In multivariate analysis, out-of-range postinduction glucose was independently associated with hypothermia (>150 mg/dL: odds ratio 2.17, 95% confidence interval (1.02, 4.61), p = 0.045; <110 mg/dL: odds ratio 2.02, 95% confidence interval (1.15, 3.55), p = 0.015), whereas preoperative HbA1c >6% was not significantly associated with hypothermia (odds ratio 1.02, 95% confidence interval (0.56, 1.84), p = 0.961). Considering only patients with diabetes, the incidence of hypothermia was lower (p = 0.002), the duration of hypothermia was shorter (p = 0.007), and the minimum temperature was higher (p = 0.006) in those with a postinduction glucose level of 110-150 mg/dL. Conclusions: The postinduction glucose level is independently associated with intraoperative hypothermia. Out-of-range postinduction glucose appeared to have an impact on the development of hypothermia in patients with diabetes, especially those with a postinduction glucose level <110 mg/dL.