bluuebunny/crossref_metadata_2025_split huggingface dataset:
GLP‐2 acutely diminishes LPS‐related intestinal permeability in rats
Authors: Akiba Yasutada , Kaji Izumi , Maruta Koji , Kaunitz Jonathan D 
Published: November 2023

Circulating lipopolysaccharide (LPS; endotoxin) increases the permeability of the gut mucosal barrier, increasing LPS translocation into the circulation, augmenting endotoxemia with consequent systemic inflammation. Although daily treatment for 1 week with glucagon‐like peptide‐2 (GLP‐2) prevents the observed LPS‐related intestinal permeability increase, presumably due to its intestinotrophic effects, we hypothesized that acute administration of GLP‐2 reduces LPS‐related increased intestinal permeability by a mechanism unlikely related to hypertrophy. We thus examined the effect of GLP‐2 on intestinal permeability dynamics in vivo and in Ussing‐chambered intestinal mucosa in vitro.We assessed intestinal permeability in vivo by measuring the appearance of intraduodenally perfused FITC‐dextran 4000 (FD4) into the portal vein (PV) in rats every 15 min for 90 min at 6 or 24 hr after LPS treatment (5 mg/kg, ip). We also examined FD4 movement from mucosal to serosal solution (m‐to‐s) in Ussing‐chambered muscle‐stripped intestinal tissues of vehicle‐ or LPS‐treated animals.6 hr after LPS treatment, PV FD4 concentrations gradually increased following bolus intraduodenal infusion of FD4 (0.1 mM). Co‐treatment with the GLP‐2 receptor antagonist GLP‐2(3–33) (1 mg/kg, ip) with LPS enhanced PV FD4 concentrations. In Ussing‐chambered ileum obtained from rats 6 hr after LPS treatment, m‐to‐s movement of FD4 was unchanged compared with controls, whereas FD4 movement was increased in the ileum of GLP‐2(3–33) co‐treated animals. Furthermore, PV GLP‐2 concentrations and proglucagon mRNA expression in ileal mucosa were increased 6 hr after LPS treatment. 24 hr after LPS treatment, PV FD4 concentrations were further increased compared to FD4 concentrations at 6 hr. Exogenous GLP‐2 treatment (100 nmol/kg, ip) 6 hr after LPS treatment reduced FD4 permeability measured 24 hr after LPS treatment.Increased intestinal permeability 6 hr after LPS administration was aggravated by GLP‐2 receptor antagonism. Systemic LPS releases endogenous GLP‐2, acutely protecting against LPS‐related loss of barrier function due to endotoxemia, followed by increased mRNA expression for the GLP‐2 precursor proglucagon. GLP‐2 treatment 6 hr after LPS administration prevented further increased intestinal permeability measured 24 hr after LPS, suggesting that the anti‐permeabilizing effects of GLP‐2 last longer than the t1/2 of the hormone. Exogenous GLP‐2 treatment may be of value in the prevention of systemic inflammation associated with endotoxemia due to a “leaky gut”.Support or Funding InformationSupported by VA Merit Review, NIH R01 DK54221, Shire Pharmaceuticals
Importance of actin dynamics in gastric epithelial repair of damage
Authors: Aihara Eitaro , Medina‐Candelaria Neisha M , Engevik Kristen A , Matthis Andrea L , Montrose Marshall H 
Published: November 2023

BackgroundSuperficial injury to the gastrointestinal (GI) epithelium requires a rapid response to prevent further damage. In the stomach, initial gastric epithelial repair involves restitution, during which neighboring cells migrate to cover the damaged area within minutes. This process is regulated by several factors, including calcium and trefoil factor 2 (TFF2). In many cell types, changes in the actin cytoskeleton are necessary for cell migration, however its role within gastric epithelial repair of damage has yet to be elucidated. In this present study, we explore the role of actin in gastric repair of damage in vivo and in vitro gastric organoids (gastroids) using human actin‐GFP (HuGE) transgenic mouse stomach.MethodsWith an anesthetized mouse on the microscope stage, the surgically exposed stomach mucosa was continuously imaged by intravital confocal/two‐photon microscopy. Selective high intensity illumination of 3–5 gastric epithelial surface cells (730 nm light) caused a microscopic lesion in the epithelium via photodamage. Gastroids were created from gastric corpus tissue of HuGE mice. Hoechst33342 (10 μg/ml) was added to image the nucleus. Photodamage was induced in a single epithelial cell nucleus in the gastroid. Dynamic changes in actin‐GFP and damage size were quantified over time.ResultsThe unperturbed actin‐GFP intracellular distribution was similar in gastric epithelium between in vivo and in vitro gastroids generated from the HuGE mice. In response to photodamage of either in vivo gastric epithelium or in vitro gastroid epithelium, actin‐GFP fluorescence decreased in the damaged cell. Subsequently, actin‐GFP expression increased in the lateral membranes neighboring the damaged cell, followed by migration inward to close the gap at the basal pole of the dead cell, in parallel with dead cell exfoliation into the lumen. This repair of damage and focal increase of actin‐GFP was significantly blocked by the calcium chelator EDTA (10 mM in the lumen in vivo, 1 mM in the medium in vitro) or the inhibition of actin polymerization (1 μM Cytochalasin D in the medium in vitro). Phalloidin (actin) staining in the gastroids, at 5 and 10 min after photodamage, showed that endogenous actin selectively increased at the leading edge of cell migration/restitution that restored epithelial continuity after cell exfoliation. Conversely, immunofluorescence of E‐cadherin increased in the trailing edge of the same restituting cells. AMD3100 (CXCR4/TFF2 inhibitor, 1 μM) and FAK inhibitor (1 μM) significantly slowed repair of damage but did not impact actin‐GFP dynamics.ConclusionActin dynamics regulated by extracellular calcium but not CXCR4 are a component of gastric restitution.Support or Funding InformationNIH RO1 DK102551 (M.H. Montrose).
Probiotic Metabolites Promote Anti‐inflammatory Functions of Immune Cells
Authors: Fu Richard H , Wu Danielle C , Yang Wei , Scoffield Jessica , Benveniste Etty N 
Published: November 2023

The microbiome is an important factor in human health and disease. Recent reports demonstrate that short‐chain fatty acids (SCFA), type of bacterial metabolites, ameliorate autoimmune diseases, indicating a link between the gut microbiome, immune cells and inflammation. In this study, we investigated the potential health benefits of probiotic bacterial metabolites by evaluating their functions in regulating the differentiation of anti‐inflammatory and pro‐inflammatory immune cells, and determining the underlying mechanisms.Using conditioned media from the probiotic bacteria, Lactococcus lactis and Lactobacillus reuteri, we demonstrated that bacterial metabolites induced differentiation of immunosuppressive anti‐inflammatory T‐regulatory (Treg) cells. Consistently, butyrate, a bacterial‐derived SCFA, enhanced the differentiation of Treg cells from naïve CD4+ T cells. Furthermore, butyrate inhibited the maturation of pro‐inflammatory antigen‐presenting dendritic cells (DCs) from hematopoietic progenitor cells. Mechanistically, we found that butyrate promoted Treg cell differentiation via increasing expression of transcription factor Foxp3 and the anti‐inflammatory cytokine IL‐10. In addition, it suppressed the maturation of DCs by inhibiting the expression of CD11c and MHC Class II, critical molecules for pathogenic CD4+ T cell activation. Taken together, these studies reveal novel functions of probiotic metabolites, SCFA, in regulating the differentiation/activation of anti‐inflammatory and pro‐inflammatory immune cells, thus inhibiting inflammation and promoting human health.Support or Funding InformationThis work was supported by the National Institute of Health grants NS057563 (E.N.B.)
Effects of Probiotic VSL#3 on Recovery from Dextran Sodium Sulfate‐Induced Colitis in Mice
Authors: Maag Kasey , Cornelius Holly , Edelman Danielle , Walton Kristen LW 
Published: November 2023

Inflammatory bowel disease (IBD) affects as many as 1.6 million Americans every year. This condition is a chronic intestinal disease that also includes Crohn's disease and ulcerative colitis. Probiotic bacteria have previously been shown to have beneficial effects in some intestinal conditions such as pouchitis, irritable bowel syndrome, and some models of IBD. We examined the effects of the probiotic cocktail VSL#3 administration for 3 days of recovery after a 5‐day treatment with 3% dextran sodium sulfate (DSS). Clinical signs of colitis, including weight loss, fecal occult blood, and fecal consistency, were observed daily during the treatment and recovery period. At the end of the experiment, samples were collected for histological scoring, fecal bacterial analysis by quantitative PCR, and analysis of colonic pro‐inflammatory cytokine expression. As expected, clinical signs of colitis were observed more frequently in DSS treated mice than in non‐DSS treated mice. However, probiotic‐treated colitic mice had clinical signs of disease similar to those of non‐probiotic treated colitic mice. Histological scoring of colitis showed a trend towards decreased histological colitis with VSL#3 treatment compared to colitic mice. Quantitative PCR for Lactobacillus 16s rRNA showed a decrease in total lactobacilli with DSS treatment that was not affected by administration of VSL#3. In conclusion, 3 days of treatment with VSL#3 following acute DSS‐induced colitis did not significantly improve recovery from colitis.Support or Funding InformationMissouri Western State University PORTAL Program
Loss of Sprouty2 in the colonic epithelium limits inflammatory cytokine production and enhances Muc2 and Lgr5 expression during colitis
Authors: Schumacher Michael A , Hsieh Jonathan J , Almohazey Dana , Warburton David , Washington M. Kay , Frey Mark R 
Published: November 2023

OBJECTIVESprouty2 (Spry2) is an intracellular modulator of MAPK signaling. Its expression is suppressed by tumor necrosis factor (TNF) in airway epithelium, but its regulation and activity in the intestinal tract are unknown. Aberrant MAPK signaling is associated with increased inflammatory cytokine production in diseases including inflammatory bowel disease, raising the possibility that Spry2 may play a role in regulating cytokine expression in the colon. MAPK is also an important regulator of secretory cell differentiation in the intestine. Here we tested the hypothesis that Spry2 regulation of MAPK signaling during colitis controls inflammatory cytokine production and goblet cell function, and thus impacts intestinal response to injury.METHODSWe generated VillinCre;Spry2FLOXXED mice that lack Spry2 in the intestinal epithelium (Spry2KOIE) and LysMCre;Spry2FLOXXED mice that lack Spry2 in cells of myeloid lineage. Mice were given 3% dextran sodium sulfate (DSS) in drinking water for 4 days followed by 3 days without DSS and colitis severity was assessed. Cytokine levels were determined by qPCR. Epithelial crypt cultures (colonoids) were generated to assess regulation of ISC and cell lineages. The role of MAPK signaling was tested with MEK inhibitor U0126.RESULTSDSS colitis caused a 59% reduction of colonic Spry2 (p<0.05). Spry2KOIE mice subjected to DSS had decreased levels of TNF, CXCL2, IL1β, and IFNγ versus wildtype littermates, and were protected from histological damage (injury score reduced by 30%, p=0.037), weight loss, and colon shortening. In contrast, mice with Spry2 deletion in myeloid cells developed acute colitis similar to controls, suggesting an epithelial specific effect of Spry2 in colitis. Spry2KOIE mice showed higher colonic Lgr5 (ISC marker) and Muc2 (goblet cell marker) levels. In vitro, Spry2KOIE‐derived colonoids also showed a 3‐fold increase (p=0.005) in Muc2 expression and elevated Lgr5 expression. Because goblet cell differentiation is thought to be dependent upon MAPK signaling, we analyzed colonoids treated with the MAPK inhibitor, U0126, but surprisingly did not see reversal of the elevated Muc2 in Spry2KOIE colonoids.CONCLUSIONOur work demonstrates that Spry2 is robustly expressed in the colonic epithelium, and expression is regulated by injury and inflammation. This may represent a protective mechanism against tissue injury by limiting inflammatory cytokine production, thus supporting Lgr5+ ISCs and inducing expression of the protective mucin, Muc2. Elevated Muc2 in Spry2KOIE colonoids was independent of MAPK activation, suggesting loss of Spry2 may elicit colonic protection through an alternative route of inhibiting inflammatory cytokine production.Support or Funding InformationNIH R01DK095004 (MRF)
G‐protein Coupled Receptor Kinase‐2 Deficiency Protects Mice from Experimentally Induced Colitis
Authors: Steury Michael , Rios‐Arce Naiomy , McCabe Laura , Parameswaran Narayanan 
Published: November 2023

G‐protein coupled receptor kinase 2 (GRK2), a member of the serine/threonine family of GPCR kinases are known for their role in GPCR phosphorylation and desensitization. In addition to this canonical role, GRK2 also modulates inflammation via non‐canonical pathways and thus has been shown to be involved in some inflammatory diseases. However, role of GRK2 in inflammatory bowel disease is not known. We hypothesized that the ablation of GRK2 would significantly modulate the pathogenesis of dextran sodium sulfate (DSS)‐induced colitis in mice. To test this, we administered DSS (in drinking water) to GRK2 heterozygous (HET) and wild type (WT) mice for 6 days followed by drinking water for 1 day. We found that GRK2 HET mice were significantly protected from DSS‐induced colitis compared to WT mice. This was demonstrated by decreased weight loss (WT 20±2.8% vs HET 11±3.4% n=6–7), lower disease activity index scores (WT 9.1 vs HET 4.1; n=6–7), and increased colon lengths (WT 4.7 cm vs HET 5.3 cm; n=6–7) in the GRK2 HET compared to WT mice. Additionally, we observed significant decrease in inflammatory cytokines including IL‐17, GM‐CSF, as well as the IL‐6/IL‐10 ratio in the colon without significant differences in cellular infiltration at 7‐day post‐DSS treatment. To further identify the cellular mechanisms by which GRK2 modulates colitis, we investigated the role for GRK2 in a myeloid‐specific GRK2 knockout. Our results demonstrate that GRK2 deficiency in the myeloid cells is sufficient for the protection observed in the heterozygous mice. Together our results indicate that GRK2 is an important mediator of colitis pathogenesis and this is conferred by the myeloid‐specific GRK2. Our results further suggest that GRK2 could be an important therapeutic target in colitis.Support or Funding InformationFunding provided through NIH Grants 4R01AT007695‐04, 5R01DK101050‐03, 5R21AI099404‐02
Targeting Palmitoyl Acyltransferase ZDHHC21 Improves Epithelial Barrier Dysfunction Resulting from Burn Induced Systemic Inflammation
Authors: Haines Ricci J , Wang Chunyan , Zhang Shimin , Eitnier Rebecca A , Wang Fang , Yang Clement GY , Wu Mack H 
Published: November 2023

Clinical studies in burn patients demonstrate a close association between leaky guts and increased incidence or severity of sepsis and other complications. Severe thermal injury triggers intestinal inflammation contributing to intestinal epithelial hyperpermeability, which exacerbates systemic response leading to multiple organ failure and sepsis. In this study, we identified a significant function of a particular palmitoyl acyltransferase (PAT), ZDHHC21, in mediating signaling events required for gut hyperpermeability induced by inflammation. Using qPCR, we showed that ZDHHC21 mRNA production was enhanced two‐fold when intestinal epithelial cells were treated with TNFα/IFNγ in vitro. Additionally, using electric cell‐substrate impedance sensing (ECIS) assays and FITC‐dextran permeability assays, and pharmacologically targeting PATs with 2‐bromopalmitate (2BP) or specific targeting of ZDHHC21 with siRNA, showed significant epithelial barrier function improvement when treated with TNFα/IFNγ. Using the ABE assay and click chemistry, we showed that TNFα/IFNγ treatment of intestinal epithelial cells results in enhanced detection of total palmitoylated proteins, and this response is inhibited by 2BP. We further explored the impact of targeting palmitoylation using ZDHHC21 deficient mice or wild‐type mice treated with 2BP and determined intestinal barrier function using mucosal permeability assays. These experiments showed that mice with impaired ZDHHC21 expression or pharmacological inhibition resulted in attenuated intestinal barrier dysfunction caused by thermal injury. Furthermore, H&E staining of small intestine and transmission electron microscopy (TEM) revealed that mice with a genetic interruption of ZDHHC21 had attenuated villus structure disorganization resulting from thermal injury induced inflammation. Taken together, these results suggest an important role of ZDHHC21 in mediating gut hyperpermeability resulting from thermal injury.Support or Funding InformationVA Merit IBX000799
Flufenamic Acid Prevents Vibrio cholerae El Tor Variant‐Induced Diarrhea via AMPK Activation and Suppression of NF‐κB‐Mediated Inflammation
Authors: Pongkorpsakol Pawin , Satitsri Saravut , Wongkrasant Preedajit , Srimanote Potjanee , Chatsudthipong Varanuj , Muanprasat Chatchai 
Published: November 2023

Pathogenesis of cholera diarrhea caused by infection with Vibrio cholerae El Tor variant (EL), a current epidemic strain of Vibrio cholerae that causes severe diarrhea in several regions, involves the nuclear factor kappa B (NF‐κB)‐mediated inflammatory responses including cyclooxygenase‐2 (COX‐2) upregulation and prostaglandin E2 (PGE2)‐induced intestinal fluid secretion and barrier disruption. The aim of this study was to evaluate the anti‐diarrheal efficacy of flufenamic acid (FFA), an non‐steroidal anti‐inflammatory drug (NSAID) that has previously been reported to stimulate AMP‐activated protein kinase (AMPK), a negative regulator of NF‐κB. We found that intraperitoneal injection of FFA (20 mg/kg) effectively reduced EL‐induced intestinal fluid secretion and intestinal barrier leakage in a mouse closed‐loop model of EL infection. In addition, FFA activated AMPK and suppressed p65 NF‐κB nuclear translocation, mRNA expression of proinflammatory cytokines and protein expressions of COX‐2 and inducible nitric oxide synthase (iNOS) in the mouse intestine infected with EL. In human intestinal epithelial cells (T84 cells), FFA induced tight junction assembly via AMPK activation. Mechanistic studies using immunoblot analysis and molecular docking prediction demonstrated that FFA activated AMPK in T84 cells by directly stimulating Ca(2+)/calmodulin dependent kinase kinase beta (CaMKKβ). Taken together, our results indicate that FFA and related compounds may be repurposed for the treatment of cholera caused by EL infection.Support or Funding InformationThis work was supported by grants BRG5980008 from the Thailand Research Fund and Mahidol University and by the Faculty of Science, Mahidol University and Faculty of graduate studies, Mahidol University.
Engaging students in the large‐lecture biology classroom
Authors: Elfring Lisa K. 
Published: November 2023

In the current era of higher‐education belt‐tightening, many institutions are dealing with resource shortages by increasing class sizes. This is particularly true for introductory‐level courses (and, at some institutions, upper‐division courses as well) in biology and other STEM disciplines. There is ample evidence from the learning sciences that students' active engagement in classes helps their learning: self‐testing, peer collaboration, explaining course concepts to others, and spaced retrieval practice are all techniques that demonstrably improve learning regardless of discipline (for examples, see Brown et al., Make It Stick, 2014). Creating classroom environments that promote these student practices is important to help students to build strong learning habits, but can seem overwhelming to those who teach large science classes.I will describe and model several course‐structure and teaching strategies I have used to create a large‐class learning environment that promotes meaningful engagement with important biology concepts and supports students as they practice the skills of active engagement. Each can be adopted on its own or in combination with any other; this incremental approach allows for customization to each instructor's personal style and the content matter taught, as well as a lower “activation energy” than a wholesale course redesign.
The t‐STEM Initiative: Faculty Inquiry in the Context of Institutional Commitments to Student Success
Authors: Jewett Sarah , LaCourse William 
Published: November 2023

In the midst of busy semester schedules, it is often difficult to create time and space for faculty to meet with colleagues in their own departments, much less the colleagues at other institutions. Within the context of the STEM Transfer Student Success Initiative (t‐STEM), a broad inter‐institutional commitment to student success, chemistry faculty across institutions committed to a collaborative inquiry in which they exchanged professional knowledge to determine how best to support student learning. The chemistry faculty members who are engaged in this generative process represent the partner institutions of Anne Arundel Community College (AACC), Community College of Baltimore County (CCBC), Howard Community College (HCC), Montgomery College (MC) and the University of Maryland, Baltimore County (UMBC).*This shared faculty experience led to a deep awareness of the curriculum and pedagogy of general chemistry coursework across institutions. Beginning from the analytic framework of the Significant Discussions publication (League for Innovation in the Community College, 2010), the team identified key differences and similarities in course experiences. Because the comparative analysis yielded many more similarities than differences, the team focused on shared curricular challenges, and created content for new instructional resources. Rather than supplementing resources for transfer students at four‐year institutions, as is a more typical outcome of this kind of work, these resources were designed to promote the success for all STEM students across institutions at any point in their academic journey.This work was undergirded by three critical and collaborative aspects of the process, including awareness, analysis, and action. In this way, the work reaches beyond the traditional boundaries of articulation and curricular alignment, and creates a new analytic space for curricular inquiry and collaboration around student learning. This focused attention contributes to a compelling national model for STEM student success, especially within the broader context of a significant inter‐institutional initiative that also addresses pre‐transfer advisement, peer mentorship, professional engagement and campus involvement. This presentation will highlight key aspects of the model, and share practices that can help other two‐year and four‐year teams to establish or enhance their own collaborative work.