Amitriptyline inhibits bronchoconstriction and directly promotes dilatation of the airways.

INTRODUCTION: The standard therapy for bronchial asthma consists of combinations of acute (short-acting ß2-sympathomimetics) and, depending on the severity of disease, additional long-term treatment (including inhaled glucocorticoids, long-acting ß2-sympathomimetics, anticholinergics, anti-IL-4R antibodies). The antidepressant amitriptyline has been identified as a relevant down-regulator of immunological TH2-phenotype in asthma, acting-at least partially-through inhibition of acid sphingomyelinase (ASM), an enzyme involved in sphingolipid metabolism. Here, we investigated the non-immunological role of amitriptyline on acute bronchoconstriction, a main feature of airway hyperresponsiveness in asthmatic disease. METHODS: After stimulation of precision cut lung slices (PCLS) from mice (wildtype and ASM-knockout), rats, guinea pigs and human lungs with mediators of bronchoconstriction (endogenous and exogenous acetylcholine, methacholine, serotonin, endothelin, histamine, thromboxane-receptor agonist U46619 and leukotriene LTD4, airway area was monitored in the absence of or with rising concentrations of amitriptyline. Airway dilatation was also investigated in rat PCLS by prior contraction induced by methacholine. As bronchodilators for maximal relaxation, we used IBMX (PDE inhibitor) and salbutamol (ß2-adrenergic agonist) and compared these effects with the impact of amitriptyline treatment. Isolated perfused lungs (IPL) of wildtype mice were treated with amitriptyline, administered via the vascular system (perfusate) or intratracheally as an inhalation. To this end, amitriptyline was nebulized via pariboy in-vivo and mice were ventilated with the flexiVent setup immediately after inhalation of amitriptyline with monitoring of lung function. RESULTS: Our results show amitriptyline to be a potential inhibitor of bronchoconstriction, induced by exogenous or endogenous (EFS) acetylcholine, serotonin and histamine, in PCLS from various species. The effects of endothelin, thromboxane and leukotrienes could not be blocked. In acute bronchoconstriction, amitriptyline seems to act ASM-independent, because ASM-deficiency (Smdp1-/-) did not change the effect of acetylcholine on airway contraction. Systemic as well as inhaled amitriptyline ameliorated the resistance of IPL after acetylcholine provocation. With the flexiVent setup, we demonstrated that the acetylcholine-induced rise in central and tissue resistance was much more marked in untreated animals than in amitriptyline-treated ones. Additionally, we provide clear evidence that amitriptyline dilatates pre-contracted airways as effectively as a combination of typical bronchodilators such as IBMX and salbutamol. CONCLUSION: Amitriptyline is a drug of high potential, which inhibits acute bronchoconstriction and induces bronchodilatation in pre-contracted airways. It could be one of the first therapeutic agents in asthmatic disease to have powerful effects on the TH2-allergic phenotype and on acute airway hyperresponsiveness with bronchoconstriction, especially when inhaled.

Pediatric IBD patients show medication and disease activity dependent changes in NK cell and CD4 memory T cell populations.

Objectives: CD4+ memory T cells facilitate long-termed adaptive immune responses while NK cells are predominately rapid effector cells with significant functions for both intestinal homeostasis and inflammation. We wanted to study both populations in health and pediatric inflammatory bowel disease (IBD) and correlate them with disease activity and medication. Methods: We performed flow cytometric analyses of peripheral blood CD4 + CD45RO+ memory T cells and CD3-CD16 + CD56+ NK cells in 30 patients with IBD and 31 age-matched controls and correlated percentages of subsets with disease activity (PUCAI/PCDAI) and medication. Results: We found a significant reduction of peripheral NK cells in overall IBD patients with both clinical remission and disease activity, which was even more pronounced in patients treated with azathioprine. Otherwise, circulating CD4+ memory T cell populations were significantly enhanced in active IBD compared to controls. Enhancement of memory T cells was particularly found in new onset disease and correlated with disease activity scores. Discussion: Our single center cohort confirms previous results showing enhanced memory T cell populations in pediatric IBD patients, which correlate with disease activity scores. CD4+ memory T cells are a relevant pathogenic leukocyte population for disease development and perpetuation in IBD. In addition, we found a decrease of NK cells in IBD patients, which was pronounced by use of azathioprine. Surveillance of both cellular populations could possibly serve as biomarker for therapy control in pediatric IBD.

A microbiota-modulated checkpoint directs immunosuppressive intestinal T cells into cancers.

Antibiotics (ABX) compromise the efficacy of programmed cell death protein 1 (PD-1) blockade in cancer patients, but the mechanisms underlying their immunosuppressive effects remain unknown. By inducing the down-regulation of mucosal addressin cell adhesion molecule 1 (MAdCAM-1) in the ileum, post-ABX gut recolonization by Enterocloster species drove the emigration of enterotropic α4ß7+CD4+ regulatory T 17 cells into the tumor. These deleterious ABX effects were mimicked by oral gavage of Enterocloster species, by genetic deficiency, or by antibody-mediated neutralization of MAdCAM-1 and its receptor, α4ß7 integrin. By contrast, fecal microbiota transplantation or interleukin-17A neutralization prevented ABX-induced immunosuppression. In independent lung, kidney, and bladder cancer patient cohorts, low serum levels of soluble MAdCAM-1 had a negative prognostic impact. Thus, the MAdCAM-1-α4ß7 axis constitutes an actionable gut immune checkpoint in cancer immunosurveillance.

Magnesium Anode Protection by an Organic Artificial Solid Electrolyte Interphase for Magnesium-Sulfur Batteries.

In the search for post-lithium battery systems, magnesium-sulfur batteries have attracted research attention in recent years due to their high potential energy density, raw material abundance, and low cost. Despite significant progress, the system still lacks cycling stability mainly associated with the ongoing parasitic reduction of sulfur at the anode surface, resulting in the loss of active materials and passivating surface layer formation on the anode. In addition to sulfur retention approaches on the cathode side, the protection of the reductive anode surface by an artificial solid electrolyte interphase (SEI) represents a promising approach, which contrarily does not impede the sulfur cathode kinetics. In this study, an organic coating approach based on ionomers and polymers is pursued to combine the desired properties of mechanical flexibility and high ionic conductivity while enabling a facile and energy-efficient preparation. Despite exhibiting higher polarization overpotentials in Mg-Mg cells, the charge overpotential in Mg-S cells was decreased by the coated anodes with the initial Coulombic efficiency being significantly increased. Consequently, the discharge capacity after 300 cycles applying an Aquivion/PVDF-coated Mg anode was twice that of a pristine Mg anode, indicating effective polysulfide repulsion from the Mg surface by the artificial SEI. This was backed by operando imaging during long-term OCV revealing a non-colored separator, i.e. mitigated self-discharge. While SEM, AFM, IR and XPS were applied to gain further insights into the surface morphology and composition, scalable coating techniques were investigated in addition to ensure practical relevance. Remarkably therein, the Mg anode preparation and all surface coatings were prepared under ambient conditions, which facilitates future electrode and cell assembly. Overall, this study highlights the important role of Mg anode coatings to improve the electrochemical performance of magnesium-sulfur batteries.

Corrigendum: Evaluation of lung function in a German single center cohort of young patients with sickle cell disease using EIT and standard techniques.

[This corrects the article DOI: 10.3389/fmed.2023.1100180.].

Evaluation of lung function in a German single center cohort of young patients with sickle cell disease using EIT and standard techniques.

Background and objective: Sickle cell disease (SCD) is a very common autosomal recessive hemoglobinopathy leading to multiple pulmonary complications that are closely associated with mortality. The pathophysiology of chronic pulmonary involvement is not yet fully understood and no specific therapies are available. Methods: The aim of this cross-sectional study was to characterize the lung function of children and young adolescents with SCD in a German single-center cohort and to extend conventional lung function testing by the use of a new imaging method. We performed spirometry and body plethysmography in 35 children and young adults with hemoglobin SS, SC, S/ß-thalassemia as well as 50 controls. These data were compared with clinical characteristics and typical laboratory parameters of hemolysis and disease activity in SCD. To identify lung inhomogeneities, for example due to atelectasis, hyperinflation, air trapping or vascular occlusions, we used the promising new method of electrical impedance tomography (EIT) and calculated global inhomogeneity indices. Results: Lung function of patients with SCD was significantly reduced compared to that of healthy controls. When the result was found to be pathological, the most commonly observed type of breathing disorder was classified as restrictive. Laboratory parameters showed typical features of SCD including decreased levels of hemoglobin and hematocrit and elevated levels of leucocytes, platelets, lactate dehydrogenase and total bilirubin. However, there was no correlation between blood values and reduced lung function. Electrical impedance tomography (EIT) revealed no abnormalities in SCD patients compared to healthy controls. In particular, we were unable to demonstrate any regional inhomogeneities in lung ventilation. Conclusion: In our study, SCD patients showed impaired lung function, with a relevant percentage of patients suffering from restrictive breathing disorder. Signs of obstruction could not be detected. Electrical impedance tomography (EIT) measurements revealed no unevenness that would suggest air entrapment, blockage of blood vessels, excessive inflation, obstruction, or other forms of lung disease. Additionally, the reduction in lung function observed in SCD patients was not related to the disease severity or laboratory test results.

NRF2/Itaconate Axis Regulates Metabolism and Inflammatory Properties of T Cells in Children with JIA.

BACKGROUND: CD4+ T cells critically contribute to the initiation and perturbation of inflammation. When CD4+ T cells enter inflamed tissues, they adapt to hypoxia and oxidative stress conditions, and to a reduction in nutrients. We aimed to investigate how this distinct environment regulates T cell responses within the inflamed joints of patients with childhood rheumatism (JIA) by analyzing the behavior of NRF2-the key regulator of the anti-oxidative stress response-and its signaling pathways. METHODS: Flow cytometry and quantitative RT-PCR were used to perform metabolic profiling of T cells and to measure the production of inflammatory cytokines. Loss of function analyses were carried out by means of siRNA transfection experiments. NRF2 activation was induced by treatment with 4-octyl-Itaconate (4-OI). RESULTS: Flow cytometry analyses revealed a high metabolic status in CD4+ T cells taken from synovial fluid (SF) with greater mitochondrial mass, and increased glucose and fatty acid uptake. This resulted in a heightened oxidative status of SF CD4+ T cells. Despite raised ROS levels, expression of NRF2 and its target gene NQO1 were lower in CD4+ T cells from SF than in those from blood. Indeed, NRF2 activation of CD4+ T cells downregulated oxidative stress markers, altered the metabolic phenotype and reduced secretion of IFN-γ. CONCLUSION: NRF2 could be a potential regulator in CD4+ T cells during chronic inflammation and could instigate a drift toward disease progression or regression, depending on the inflammatory environment.

Update of evidence- and consensus-based guidelines for the treatment of juvenile idiopathic arthritis (JIA) by the German Society of Pediatric and Juvenile Rheumatic Diseases (GKJR): New perspectives on interdisciplinary care.

BACKGROUND: New therapeutic strategies for juvenile idiopathic arthritis (JIA) have evolved within the past ten years, and as a result, an update of the 2011 recommendations of the German management guidelines was initiated. METHODS: A systemic literature review was performed, overarching principles were proposed and pre-selected via an online survey followed by two multidisciplinary consensus conferences. Pharmacological and non-pharmacological treatments were discussed, statements were proposed and ultimately agreed upon by nominal group technique (NGT). RESULTS: 12 overarching therapeutic principles, as well as 9 recommendations on pharmacological and 5 on non-pharmacological treatments for JIA were agreed upon. CONCLUSION: This report summarizes the recent update of the interdisciplinary, consensus-based German guidelines on the management of JIA. The multi- and interdisciplinary participation of all caregivers was central for this patient-focused update. With these guidelines, physicians can choose an evidence-based approach, which allows better tailored treatment in this vulnerable cohort of children and adolescents.

Cross-sectional seroprevalence surveys of SARS-CoV-2 antibodies in children in Germany, June 2020 to May 2021.

The rate of SARS-CoV-2 infections in children remains unclear due to many asymptomatic cases. We present a study of cross-sectional seroprevalence surveys of anti-SARS-CoV-2 IgG in 10,358 children recruited in paediatric hospitals across Germany from June 2020 to May 2021. Seropositivity increased from 2.0% (95% CI 1.6, 2.5) to 10.8% (95% CI 8.7, 12.9) in March 2021 with little change up to May 2021. Rates increased by migrant background (2.8%, 4.4% and 7.8% for no, one and two parents born outside Germany). Children under three were initially 3.6 (95% CI 2.3, 5.7) times more likely to be seropositive with levels equalising later. The ratio of seropositive cases per recalled infection decreased from 8.6 to 2.8. Since seropositivity exceeds the rate of recalled infections considerably, serologic testing may provide a more valid estimate of infections, which is required to assess both the spread and the risk for severe outcomes of SARS-CoV-2 infections.

Working Towards a Treat-to-Target Protocol in Juvenile Proliferative Lupus Nephritis - A Survey of Pediatric Rheumatologists and Nephrologists in Germany and Austria.

Background: To describe treatment practices for juvenile proliferative lupus nephritis (LN) class III and IV of pediatric rheumatologists and nephrologists in Germany and Austria in preparation for a treat-to-target treatment protocol in LN. Methods: Survey study by members of the Society for Pediatric and Adolescent Rheumatology (GKJR) and the German Society for Pediatric Nephrology (GPN) on diagnostics and (concomitant) therapy of LN. Results: Fifty-eight physicians completed the survey. Overall, there was a considerable heterogeneity regarding the suggested diagnostics and management of juvenile proliferative LN. Increased urinary protein excretion, either assessed by 24 h urine collection or spot urine (protein-creatinine ratio), and reduced estimated glomerular filtration rate were specified as important parameters for indication of kidney biopsy to diagnose proliferative LN and monitoring of therapy. Corticosteroids were generally proposed for induction and maintenance therapy, most often in conjunction with either mycophenolate mofetil (MMF) or cyclophosphamide (CP) as steroid-sparing immunosuppressants. MMF was clearly preferred over CP for induction therapy of LN class III, whereas CP and MMF were equally proposed for LN class IV. MMF was most often recommended for maintenance therapy in conjunction with oral corticosteroids and continued for at least 3 years and 1 year, respectively, after remission. Hydroxychloroquine was widely accepted as a concomitant measure followed by renin-angiotensin system inhibitors in cases of arterial hypertension and/or proteinuria. Conclusion: The majority of pediatric rheumatologists and nephrologists in Germany and Austria propose the use of corticosteroids, most often in combination with either MMF or CP, for treatment of proliferative LN in children. The considerable heterogeneity of responses supports the need for a treat-to-target protocol for juvenile proliferative LN between pediatric rheumatologists and nephrologists.

miR-23a contributes to T cellular redox metabolism in juvenile idiopathic oligoarthritis.

OBJECTIVE: JIA is a chronic inflammatory disease of unknown origin. The regulation of inflammatory processes involves multiple cellular steps including mRNA transcription and translation. Different miRNAs control these processes tightly. We aimed to determine the roles of specific miRNAs within JIA pathogenesis. METHODS: We performed a global miRNA expression analysis in parallel in cells from the arthritic joint and peripheral blood of oligoarticular JIA patients and healthy controls. Quantitative RT-PCR analysis was used to verify expression of miRNA in T cells. Ex vivo experiments and flow cytometric analyses were used to analyse proliferation and redox metabolism. RESULTS: Global miRNA expression analysis demonstrated a different composition of miRNA expression at the site of inflammation compared with peripheral blood. Bioinformatic analysis of predicted miRNA target genes suggest a huge overrepresentation of genes involved in metabolic and oxidative stress pathways in the inflamed joint. Despite enhanced reactive oxygen species (ROS) levels within the local inflammatory milieu, JIA T cells are hyperproliferative and reveal an overexpression of miR-23a, which is an inhibitor of Peptidyl-prolyl isomerase F (PPIF), the regulator of mitochondrial ROS escape. Mitochondrial ROS escape is diminished in JIA T cells, resulting in their prolonged survival. CONCLUSION: Our data suggest that miRNA-dependent mitochondrial ROS shuttling might be a mechanism that contributes to T cell regulation in JIA at the site of inflammation.

Cognate recognition of microbial antigens defines constricted CD4+ T cell receptor repertoires in the inflamed colon.

Key aspects of intestinal T cells, including their antigen specificity and their selection by the microbiota and other intestinal antigens, as well as the contribution of individual T cell clones to regulatory and effector functions, remain unresolved. Here we tracked adoptively transferred T cell populations to specify the interrelation of T cell receptor repertoire and the gut antigenic environment. We show that dominant TCRα clonotypes were shared between interferon-γ- and interleukin-17-producing but not regulatory Foxp3+ T cells. Identical TCRα clonotypes accumulated in the colon of different individuals, whereas antibiotics or defined colonization correlated with the expansion of distinct expanded T cell clonotypes. Our results demonstrate key aspects of intestinal CD4+ T cell activation and suggest that few microbial species exert a dominant effect on the intestinal T cell repertoire during colitis. We speculate that dominant proinflammatory T cell clones might provide a therapeutic target in human inflammatory bowel disease.

Modeling of Electron-Transfer Kinetics in Magnesium Electrolytes: Influence of the Solvent on the Battery Performance.

The performance of rechargeable magnesium batteries is strongly dependent on the choice of electrolyte. The desolvation of multivalent cations usually goes along with high energy barriers, which can have a crucial impact on the plating reaction. This can lead to significantly higher overpotentials for magnesium deposition compared to magnesium dissolution. In this work we combine experimental measurements with DFT calculations and continuum modelling to analyze Mg deposition in various solvents. Jointly, these methods provide a better understanding of the electrode reactions and especially the magnesium deposition mechanism. Thereby, a kinetic model for electrochemical reactions at metal electrodes is developed, which explicitly couples desolvation to electron transfer and, furthermore, qualitatively takes into account effects of the electrochemical double layer. The influence of different solvents on the battery performance is studied for the state-of-the-art magnesium tetrakis(hexafluoroisopropyloxy)borate electrolyte salt. It becomes apparent that not necessarily a whole solvent molecule must be stripped from the solvated magnesium cation before the first reduction step can take place. For Mg reduction it seems to be sufficient to have one coordination site available, so that the magnesium cation is able to get closer to the electrode surface. Thereby, the initial desolvation of the magnesium cation determines the deposition reaction for mono-, tri- and tetraglyme, whereas the influence of the desolvation on the plating reaction is minor for diglyme and tetrahydrofuran. Overall, we can give a clear recommendation for diglyme to be applied as solvent in magnesium electrolytes.

A Family of Heterobimetallic Cubes Shows Spin-Crossover Behaviour Near Room Temperature.

Using 4-(4'-pyridyl)aniline as a simple organic building block in combination with three different aldehyde components together with metal(II) salts gave three different Fe8 Pt6 -cubes and their corresponding Zn8 Pt6 analogues by employing the subcomponent self-assembly approach. Whereas the use of zinc(II) salts gave rise to diamagnetic cages, iron(II) salts yielded metallosupramolecular cages that show spin-crossover behaviour in solution. The spin-transition temperature T1/2 depends on the incorporated aldehyde component, giving a construction kit for the deliberate synthesis of spin-crossover compounds with tailored transition properties. Incorporation of 4-thiazolecarbaldehyde or N-methyl-2-imidazole-carbaldehyde yielded cages that undergo spin-crossover around room temperature whereas the cage obtained using 1H-4-imidazolecarbaldehyde shows a spin-transition at low temperatures. Three new structures were characterized by synchrotron X-ray diffraction and all structures were characterized by mass spectrometry, NMR and UV/Vis spectroscopy.

Upregulation of Anti-Oxidative Stress Response Improves Metabolic Changes in L-Selectin-Deficient Mice but Does Not Prevent NAFLD Progression or Fecal Microbiota Shifts.

(1) Background: Non-alcoholic fatty liver disease (NAFLD) is a growing global health problem. NAFLD progression involves a complex interplay of imbalanced inflammatory cell populations and inflammatory signals such as reactive oxygen species and cytokines. These signals can derive from the liver itself but also from adipose tissue or be mediated via changes in the gut microbiome. We analyzed the effects of a simultaneous migration blockade caused by L-selectin-deficiency and an enhancement of the anti-oxidative stress response triggered by hepatocytic Kelch-like ECH-associated protein 1 (Keap1) deletion on NAFLD progression. (2) Methods: L-selectin-deficient mice (Lsel-/-Keap1flx/flx) and littermates with selective hepatic Keap1 deletion (Lsel-/-Keap1Δhepa) were compared in a 24-week Western-style diet (WD) model. (3) Results: Lsel-/-Keap1Δhepa mice exhibited increased expression of erythroid 2-related factor 2 (Nrf2) target genes in the liver, decreased body weight, reduced epidydimal white adipose tissue with decreased immune cell frequencies, and improved glucose response when compared to their Lsel-/-Keap1flx/flx littermates. Although WD feeding caused drastic changes in fecal microbiota profiles with decreased microbial diversity, no genotype-dependent shifts were observed. (4) Conclusions: Upregulation of the anti-oxidative stress response improves metabolic changes in L-selectin-deficient mice but does not prevent NAFLD progression and shifts in the gut microbiota.

Aggressive infantile myofibromatosis with intestinal involvement.

BACKGROUND: Infantile myofibromatosis (IM) is the most common cause of multiple fibrous tumors in infancy. Multicentric disease can be associated with life-threatening visceral lesions. Germline gain-of-function mutations in PDGFRB have been identified as the most common molecular defect in familial IM. CASE PRESENTATION: We here describe an infant with PDGFRB-driven IM with multiple tumors at different sites, including intestinal polyposis with hematochezia, necessitating temporary chemotherapy. CONCLUSIONS: PDGFRB-driven IM is clinically challenging due to its fluctuating course and multiple organ involvement in the first years of life. Early molecular genetic analysis is necessary to consider tyrosine kinase inhibitor treatment in case of aggressive visceral lesions.

C2orf69 mutations disrupt mitochondrial function and cause a multisystem human disorder with recurring autoinflammation.

BACKGROUNDDeciphering the function of the many genes previously classified as uncharacterized open reading frame (ORF) would complete our understanding of a cell's function and its pathophysiology.METHODSWhole-exome sequencing, yeast 2-hybrid and transcriptome analyses, and molecular characterization were performed in this study to uncover the function of the C2orf69 gene.RESULTSWe identified loss-of-function mutations in the uncharacterized C2orf69 gene in 8 individuals with brain abnormalities involving hypomyelination and microcephaly, liver dysfunction, and recurrent autoinflammation. C2orf69 contains an N-terminal signal peptide that is required and sufficient for mitochondrial localization. Consistent with mitochondrial dysfunction, the patients showed signs of respiratory chain defects, and a CRISPR/Cas9-KO cell model of C2orf69 had similar respiratory chain defects. Patient-derived cells revealed alterations in immunological signaling pathways. Deposits of periodic acid-Schiff-positive (PAS-positive) material in tissues from affected individuals, together with decreased glycogen branching enzyme 1 (GBE1) activity, indicated an additional impact of C2orf69 on glycogen metabolism.CONCLUSIONSOur study identifies C2orf69 as an important regulator of human mitochondrial function and suggests that this gene has additional influence on other metabolic pathways.

Alveolar capillary dysplasia without misalignment of pulmonary veins, hyperinflammation, megalocornea and overgrowth - Association with a homozygous 2bp-insertion in LTBP2?

We present a male infant with alveolar capillary dysplasia without misalignment of pulmonary veins, hyperinflammation, megalocornea and macrosomia/macrocephaly at birth. Whole-exome sequencing revealed a homozygous 2bp-insertion in the latent transforming growth factor-beta binding protein 2 (LTBP2) (c.278_279dup, p.(Ser94Glyfs*187)). So far, LTBP2-variants have been frequently reported with an eye-restricted phenotype including primary congenital glaucoma and megalocornea/microspherphakia and ectopia lentis with/without secondary glaucoma. Hitherto reported systemic phenotypes showed, among others, features as tall stature, finger anomalies, high-arched palate and cardiovascular anomalies. The main pathophysiological finding of our patient was an alveolar capillary dysplasia (with pulmonary arterial hypertension and right ventricular impairment but without misalignment of pulmonary veins) resulting in almost continuous oxygen demand and prolonged dependence on mechanical ventilation. He died of respiratory failure at the age of seven months. This patient may extend the LTBP2-related phenotype with resulting diagnostic implications.

MAdCAM-1/α4ß7 Integrin-Mediated Lymphocyte/Endothelium Interactions Exacerbate Acute Immune-Mediated Hepatitis in Mice.

BACKGROUND & AIMS: Aberrant lymphocyte homing could potentially link inflammatory processes in the intestine and the liver, as distinct hepatobiliary diseases frequently develop as extra-intestinal manifestations in inflammatory bowel disease. In this study, we examined the role of the gut-tropic leukocyte adhesion molecule ß7 integrin and its endothelial ligand mucosal addressin cell-adhesion molecule-1 (MAdCAM-1) in immune-mediated hepatitis in mice. METHODS: Wild-type (WT) mice, MAdCAM-1-deficient mice, ß7 integrin-deficient mice, RAG-2-deficient mice, RAG-2/MAdCAM-1 double-deficient mice, and RAG-2/ß7 integrin double-deficient mice were subjected to concanavalin A (ConA)-induced hepatitis. The degree of hepatitis was evaluated by histology, flow cytometry, and expression analysis of inflammatory mediators. The motility of lymphocytes in progressive liver damage was assessed by intravital laser scanning multiphoton microscopy. RESULTS: Ablation of MAdCAM-1 or ß7 integrin ameliorated ConA-induced hepatitis in mice. ß7 integrin-deficient lymphocytes caused less liver damage than WT lymphocytes in ConA-treated RAG-2-deficient mice. Moreover, WT lymphocytes caused less liver damage in ConA-treated RAG-2/ß7 integrin double-deficient mice than in similarly treated RAG-2-deficient mice, indicating that ß7 integrin expression contributes significantly to the liver damage mediated by innate immune cells. MAdCAM-1 expression was dependent on ß7 integrin expression on adaptive and innate immune cells. Most importantly, lymphocytes in ConA-treated MAdCAM-1-deficient mice displayed more motility and less adhesion in the liver sinusoids in vivo, than lymphocytes in similarly treated WT mice. CONCLUSIONS: These data suggest that ß7 integrin expression on lymphocytes and innate immune cells contributes to MAdCAM-1 upregulation and liver damage in acute immune-mediated hepatitis, most likely by facilitating lymphocyte/sinusoidal endothelial cell interactions.

L-Selectin/CD62L is a Key Driver of Non-Alcoholic Steatohepatitis in Mice and Men.

CD62L (L-Selectin) dependent lymphocyte infiltration is known to induce inflammatory bowel disease (IBD), while its function in the liver, especially in non-alcoholic steatohepatitis (NASH), remains unclear. We here investigated the functional role of CD62L in NASH in humans as well as in two mouse models of steatohepatitis. Hepatic expression of a soluble form of CD62L (sCD62L) was measured in patients with steatosis and NASH. Furthermore, CD62L-/- mice were fed with a methionine and choline deficient (MCD) diet for 4 weeks or with a high fat diet (HFD) for 24 weeks. Patients with NASH displayed increased serum levels of sCD62L. Hepatic CD62L expression was higher in patients with steatosis and increased dramatically in NASH patients. Interestingly, compared to wild type (WT) mice, MCD and HFD-treated CD62L-/- mice were protected from diet-induced steatohepatitis. This was reflected by less fat accumulation in hepatocytes and a dampened manifestation of the metabolic syndrome with an improved insulin resistance and decreased cholesterol and triglyceride levels. Consistent with ameliorated disease, CD62L-/- animals exhibited an enhanced hepatic infiltration of Treg cells and a strong activation of an anti-oxidative stress response. Those changes finally resulted in less fibrosis in CD62L-/- mice. Additionally, this effect could be reproduced in a therapeutic setting by administrating an anti-CD62L blocking antibody. CD62L expression in humans and mice correlates with disease activity of steatohepatitis. CD62L knockout and anti-CD62L-treated mice are protected from diet-induced steatohepatitis suggesting that CD62L is a promising target for therapeutic interventions in NASH.