Inhibition of 5-lipoxygenase alleviates graft-versus-host disease

Anandamide reduces the migration of lymphocytes to the intestine by CB2 activation and reduces TNF-α in the target organs, protecting mice from graft-versus-host disease

Graft-versus-host disease (GVHD) is a serious inflammatory illness that often occurs as a secondary complication of bone marrow transplantation. Current therapies have limited effectiveness and fail to achieve a balance between inflammation and the graft-versus-tumor effect. In this study, we investigate the effects of the endocannabinoid anandamide on the complex pathology of GVHD. We assess the effects of an irreversible inhibitor of fatty acid amine hydrolase or exogenous anandamide and find that they increase survival and reduce clinical signs in GVHD mice. In the intestine of GVHD mice, treatment with exogenous anandamide also leads to a reduction in the number of CD3+, CD3+CD4+, and CD3+CD8+ cells, which reduces the activation of CD3+CD4+ and CD3+CD8+ cells, as assessed by enhanced CD28 expression, a T cell co-stimulatory molecule. Exogenous AEA was also able to reduce TNF-α and increase IL-10 in the intestine of GVHD mice. In the liver, exogenous AEA reduces injury, TNF-α levels, and the number of CD3+CD8+ cells. Interestingly, anandamide reduces Mac-1α, which lowers the adhesion of transplanted cells in mesenteric veins. These effects are mimicked by JWH133-a CB2 selective agonist-and abolished by treatment with a CB2 antagonist. Furthermore, the effects caused by anandamide treatment on survival were related to the CB2 receptor, as the CB2 antagonist abolished it. This study shows the critical role of the CB2 receptor in the modulation of the inflammatory response of GVHD by treatment with anandamide, the most prominent endocannabinoid.

Cardiac disturbances and changes in tissue cytokine levels in mice fed with a high-refined carbohydrate diet

AIMS

The consumption of highly refined carbohydrates increases systemic inflammatory markers, but its potential to exert direct myocardial inflammation is uncertain. Herein, we addressed the impact of a high-refined carbohydrate (HC) diet on mice heart and local inflammation over time.

MAIN METHODS

BALB/c mice were fed with a standard chow (control) or an isocaloric HC diet for 2, 4, or 8 weeks (HC groups), in which the morphometry of heart sections and contractile analyses by invasive catheterization and Langendorff-perfused hearts were assessed. Cytokines levels by ELISA, matrix metalloproteinase (MMP) activity by zymography, in situ reactive oxygen species (ROS) staining and lipid peroxidation-induced TBARS levels, were also determined.

KEY FINDINGS

HC diet fed mice displayed left ventricular hypertrophy and interstitial fibrosis in all times analyzed, which was confirmed by echocardiographic analyses of 8HC group. Impaired contractility indices of HC groups were observed by left ventricular catheterization, whereas ex vivo and in vitro indices of contraction under isoprenaline-stimulation were higher in HC-fed mice compared with controls. Peak levels of TNF-α, TGF-β, ROS, TBARS, and MMP-2 occur independently of HC diet time. However, a long-lasting local reduction of the anti-inflammatory cytokine IL-10 was found, which was linearly correlated to the decline of systolic function in vivo.

SIGNIFICANCE

Altogether, the results indicate that short-term consumption of HC diet negatively impacts the balance of anti-inflammatory defenses and proinflammatory/profibrotic mediators in the heart, which can contribute to HC diet-induced morphofunctional cardiac alterations.

Shared nociceptive dorsal root ganglion neurons participating in acupoint sensitization

When the body is under pathological stress (injury or disease), the status of associated acupoints changes, including decreased pain threshold. Such changes in acupoint from a “silent” to an “active” state are considered “acupoint sensitization,” which has become an important indicator of acupoint selection. However, the mechanism of acupoint sensitization remains unclear. In this study, by retrograde tracing, morphological, chemogenetic, and behavioral methods, we found there are some dorsal root ganglion (DRG) neurons innervating the ST36 acupoint and ipsilateral hind paw (IHP) plantar simultaneously. Inhibition of these shared neurons induced analgesia in the complete Freund’s adjuvant (CFA) pain model and obstruction of nociceptive sensation in normal mice, and elevated the mechanical pain threshold (MPT) of ST36 acupoint in the CFA model. Excitation of shared neurons induced pain and declined the MPT of ST36 acupoint. Furthermore, most of the shared DRG neurons express TRPV1, a marker of nociceptive neurons. These results indicate that the shared nociceptive DRG neurons participate in ST36 acupoint sensitization in CFA-induced chronic pain. This raised a neural mechanism of acupoint sensitization at the level of primary sensory transmission.

Therapeutic effect of the sulforaphane derivative JY4 on ulcerative colitis through the NF-κB-p65 pathway

The efficacy of the sulforaphane derivative JY4 was evaluated in acute and chronic mouse models of ulcerative colitis induced by dextran sodium sulfate. Oral administration of JY4 led to significant improvements in symptoms, with recovery of body weight and colorectal length, together with reduced diarrhoea, bloody stools, ulceration of colonic tissue and infiltration of inflammatory cells. The oral bioavailability of JY4, determined by comparing oral dosing with injection into the tail vein, was 5.67%, which was comply with the idea in the intestinal function. Using a dual-luciferase reporter assay, immunofluorescence studies, western blot analysis and immunohistochemical staining, JY4 was shown to significant interfere with the NF-κB-p65 signaling pathway. By preventing the activation of NF-κB-p65, JY4 inhibited the overexpression of downstream inflammatory factors, thereby exerting an anti-inflammatory effect on the intestinal tract. This study thus provides a promising candidate drug, and a new concept for the treatment of ulcerative colitis.

Pretransplant Systemic Lipidomic Profiles in Allogeneic Stem Cell Transplant Recipients

Simple Summary

Stem cell transplantation is used in the treatment of aggressive hematological malignancies and consists of initial high-dose and potentially lethal chemotherapy, followed by rescue with the transplantation of hematopoietic stem cells. Transplantation with stem cells from a healthy donor (i.e., allogeneic stem cells) has the strongest anti-cancer effect, but also the highest risk of severe toxicity. Furthermore, the clinical status at the time of transplantation (inflammation, fluid overload) is associated with posttransplant mortality, and immune-mediated acute graft-versus-host disease (GVHD) is a potential lethal complication. Finally, lipid metabolism regulates the proliferation and survival of both malignant hematological cells and immunocompetent cells that cause GVHD. Our study shows that the pretransplant lipid profiles differ between allotransplant recipients and can be used for the subclassification of patients and possibly to identify patients with an increased risk of death due to disease relapse or treatment toxicity. The therapeutic targeting of lipid metabolism should therefore be further explored in these transplant recipients.

Abstract

Allogeneic stem cell transplantation is used in the treatment of high-risk hematological malignancies. However, this treatment is associated with severe treatment-related morbidity and mortality. The metabolic status of the recipient may be associated with the risk of development of transplant-associated complications such as graft-versus-host disease (GVHD). To better understand the impact of the lipidomic profile of transplant recipients on posttransplant complications, we evaluated the lipid signatures of patients with hematological disease using non-targeted lipidomics. In the present study, we studied pretransplant serum samples derived from 92 consecutive patients with acute myeloid leukemia (AML) or high-risk myelodysplastic syndrome (MDS). A total of 960 lipid biochemicals were identified, and the pretransplant lipidomic profiles differed significantly when comparing patients with and without the risk factors: (i) pretransplant inflammation, (ii) early fluid overload, and (iii) patients with and without later steroid-requiring acute GVHD. All three factors, but especially patients with pretransplant inflammation, were associated with decreased levels of several lipid metabolites. Based on the overall concentrations of various lipid subclasses, we identified a patient subset characterized by low lipid levels, increased frequency of MDS patients, signs of inflammation, decreased body mass index, and an increased risk of early non-relapse mortality. Metabolic targeting has been proposed as a possible therapeutic strategy in allotransplant recipients, and our present results suggest that the clinical consequences of therapeutic intervention (e.g., nutritional support) will also differ between patients and depend on the metabolic context.

Prospective phase II trial of montelukast to treat bronchiolitis obliterans syndrome after hematopoietic cell transplant and investigation into BOS pathogenesis

BACKGROUND

Bronchiolitis obliterans syndrome (BOS) is a severe manifestation of chronic graft-versus-host disease (cGVHD) following hematopoietic cell transplantation (HCT). Montelukast interrupts cysteinyl leukotriene activity and may diminish the activation and homing of cells to bronchioles and subsequent fibrosis.

OBJECTIVE

We performed a prospective phase II trial to test whether montelukast altered lung decline for patients with BOS after HCT.

STUDY DESIGN

We performed a single arm, open-label, multi-institutional study with primary endpoints of: i) FEV1 stability or improvement (<15% decline) and ii) slope of FEV1<1 point decline after six months treatment. Secondary endpoints included symptom and functional response, and immune correlates investigating the role of leukotrienes in BOS progression.

RESULTS

25 patients enrolled with moderate to severe lung disease after three months of stable cGVHD therapy. Montelukast was well-tolerated and no patient required escalation of BOS-directed therapy. At the primary endpoint, all evaluable patients (n=23) met criteria for treatment success using FEV1% predicted, and all but one had stable or improved FEV1 slope. In those with >5% FEV1 improvement, clinically meaningful improvements were seen in the Lee scores of breathing, energy, and mood. Improvements in the Human Activity Profile and 6-minute-walk test were observed in those with <5% FEV1 decline. Overall survival was 87% at two-years. Immune correlates showed elevated leukotriene receptor levels on blood eosinophils and monocytes vs. healthy controls, elevated urine leukotrienes in 45% of cohort, and cysteinyl leukotriene receptors on bronchoalveolar lavage subsets and a predominance of Th2 T cells, all pre-treatment.

CONCLUSIONS

These data suggest that montelukast may safely halt progression of BOS after HCT and that leukotrienes may play a role in the biology of BOS.

T-Cell Metabolism in Graft Versus Host Disease

Allogeneic-hematopoietic stem cell transplantation (allo-HSCT) represents the only curative treatment option for numerous hematological malignancies. Elimination of malignant cells depends on the T-cells' Graft-versus-Tumor (GvT) effect. However, Graft-versus-Host-Disease (GvHD), often co-occurring with GvT, remains an obstacle for therapeutic efficacy. Hence, approaches, which selectively alleviate GvHD without compromising GvT activity, are needed. As already explored for autoimmune and inflammatory disorders, immuno-metabolic interventions pose a promising option to address this unmet challenge. Being embedded in a complex regulatory framework, immunological and metabolic pathways are closely intertwined, which is demonstrated by metabolic reprograming of T-cells upon activation or differentiation. In this review, current knowledge on the immuno-metabolic signature of GvHD-driving T-cells is summarized and approaches to metabolically interfere are outlined. Furthermore, we address the metabolic impact of standard medications for GvHD treatment and prophylaxis, which, in conjunction with the immuno-metabolic profile of alloreactive T-cells, could allow more targeted interventions in the future.

High Throughput Analysis Reveals Changes in Gut Microbiota and Specific Fecal Metabolomic Signature in Hematopoietic Stem Cell Transplant Patients

There is mounting evidence for the emerging role of gut microbiota (GM) and its metabolites in profoundly impacting allogenic hematopoietic stem cell transplantation (allo-HSCT) and its subsequent complications, mainly infections and graft versus host-disease (GvHD). The present study was performed in order to investigate changes in GM composition and fecal metabolic signature between transplant patients (n = 15) and healthy controls (n = 18). The intestinal microbiota was characterized by NGS and gas chromatography-mass spectrometry was employed to perform untargeted analysis of fecal metabolites. We found lower relative abundances of Actinobacteria, Firmicutes, and Bacteroidetes and a higher abundance of Proteobacteria phylum after allo-HSCT. Particularly, the GvHD microbiota was characterized by a lower relative abundance of the short-chain fatty acid-producing bacteria, namely, the Feacalibacterium, Akkermansia, and Veillonella genera and the Lachnospiraceae family, and an enrichment in multidrug-resistant bacteria belonging to Escherichia, Shigella, and Bacteroides. Moreover, network analysis showed that GvHD was linked to a higher number of positive interactions of Blautia and a significant mutual-exclusion rate of Citrobacter. The fecal metabolome was dominated by lipids in the transplant group when compared with the healthy individuals (p < 0.05). Overall, 76 metabolites were significantly altered within transplant recipients, of which 24 were selected as potential biomarkers. Furthermore, the most notable altered metabolic pathways included the TCA cycle; butanoate, propanoate, and pyruvate metabolisms; steroid biosynthesis; and glycolysis/gluconeogenesis. Specific biomarkers and altered metabolic pathways were correlated to GvHD onset. Our results showed significant shifts in gut microbiota structure and fecal metabolites characterizing allo-HSCT.

Effect of Physical Training on Exercise-Induced Inflammation and Performance in Mice

Acute exercise increases the amount of circulating inflammatory cells and cytokines to maintain physiological homeostasis. However, it remains unclear how physical training regulates exercise-induced inflammation and performance. Here, we demonstrate that acute high intensity exercise promotes an inflammatory profile characterized by increased blood IL-6 levels, neutrophil migratory capacity, and leukocyte recruitment to skeletal muscle vessels. Moreover, we found that physical training amplified leukocyte-endothelial cell interaction induced by acute exercise in skeletal muscle vessels and diminished exercise-induced inflammation in skeletal muscle tissue. Furthermore, we verified that disruption of the gp-91 subunit of NADPH-oxidase inhibited exercise-induced leukocyte recruitment on skeletal muscle after training with enhanced exercise time until fatigue. In conclusion, the training was related to physical improvement and immune adaptations. Moreover, reactive oxygen species (ROS) could be related to mechanisms to limit aerobic performance and its absence decreases the inflammatory response elicited by exercise after training.

Metabolic Reprogramming-A New Era How to Prevent and Treat Graft Versus Host Disease After Allogeneic Hematopoietic Stem Cell Transplantation Has Begun

Allogeneic hematopoietic stem cell transplantation (HSCT) is the solitary therapeutic therapy for many types of hematological cancers. The benefits of this procedure are challenged by graft vs. host disease (GVHD), causing significant morbidity and mortality. Recent advances in the metabolomics field have revolutionized our understanding of complex human diseases, clinical diagnostics and allow to trace the de novo biosynthesis of metabolites. There is growing evidence for metabolomics playing a role in different aspects of GVHD, and therefore metabolomic reprogramming presents a novel tool for this disease. Pre-transplant cytokine profiles and metabolic status of allogeneic transplant recipients is shown to be linked with a threat of acute GVHD. Immune reactions underlying the pathophysiology of GVHD involve higher proliferation and migration of immune cells to the target site, requiring shifts in energy supply and demand. Metabolic changes and reduced availability of oxygen result in tissue and cellular hypoxia which is extensive enough to trigger transcriptional and translational changes. T cells, major players in acute GVHD pathophysiology, show increased glucose uptake and glycolytic activity. Effector T (Teff) cells activated during nutrient limiting conditions in vitro or multiplying during GVHD in vivo, depend more on oxidative phosphorylation (OXPHOS) and fatty acid oxidation (FAO). Dyslipidemia, such as the increase of medium and long chain fatty and polyunsaturated acids in plasma of GVHD patients, has been observed. Sphingolipids associate with inflammatory conditions and cancer. Chronic GVHD (cGVHD) patients show reduced branched-chain amino acids (BCAAs) and increased sulfur-containing metabolites post HSCT. Microbiota-derived metabolites such as aryl hydrocarbon receptor (AhR) ligands, bile acids, plasmalogens and short chain fatty acids vary significantly and affect allogeneic immune responses during acute GVHD. Considering the multitude of possibilities, how altered metabolomics are involved in GVHD biology, multi-timepoints related and multivariable biomarker panels for prognosticating and understanding GVHD are needed. In this review, we will discuss the recent work addressing metabolomics reprogramming to control GVHD in detail.

Role of SOCS2 in the Regulation of Immune Response and Development of the Experimental Autoimmune Encephalomyelitis

Multiple sclerosis (MS) is an inflammatory disease of the central nervous system (CNS). Experimental Autoimmune Encephalomyelitis (EAE) is the most widely used animal model for the study of MS. The Suppressor of Cytokine Signaling (SOCS) 2 protein plays a critical role in regulating the immune responses. The role of SOCS2 during EAE has not been explored. EAE was induced in WT and SOCS2^−/− mice using myelin oligodendrocyte glycoprotein (MOG_35-55) peptide. Brain and spinal cord were examined during the peak (day 14) and recovery phase (day 28) of the disease. SOCS2 was upregulated in the brain of WT mice at the peak and recovery phase of EAE. The development of the acute phase was slower in onset in SOCS2^−/− mice and was associated with reduced number of Th1 (CD3⁺CD4⁺IFN-γ⁺) cells in the spinal cord and brain. However, while in WT mice, maximal clinical EAE score was followed by a progressive recovery; the SOCS2^−/− mice were unable to recover from locomotor impairment that occurred during the acute phase. There was a prolonged inflammatory response (increased Th1 and decreased Th2 and T regulatory cells) in the late phase of EAE in the CNS of SOCS2^−/− mice. Transplantation of bone marrow cells from SOCS2^−/− into irradiated WT mice resulted in higher lethality at the early phase of EAE. Altogether, these results suggest that SOCS2 plays a dual role in the immune response during EAE. It is necessary for damage during the acute phase damage but plays a beneficial role in the recovery stage of the disease.

Metabolomics analysis of human acute graft-versus-host disease reveals changes in host and microbiota-derived metabolites

Despite improvement in clinical management, allogeneic hematopoietic stem cell transplantation (HSCT) is still hampered by high morbidity and mortality rates, mainly due to graft versus host disease (GvHD). Recently, it has been demonstrated that the allogeneic immune response might be influenced by external factors such as tissues microenvironment or host microbiota. Here we used high throughput metabolomics to analyze two cohorts of genotypically HLA-identical related recipient and donor pairs. Metabolomic profiles markedly differ between recipients and donors. At the onset of acute GvHD, in addition to host-derived metabolites, we identify significant variation in microbiota-derived metabolites, especially in aryl hydrocarbon receptor (AhR) ligands, bile acids and plasmalogens. Altogether, our findings support that the allogeneic immune response during acute GvHD might be influenced by bile acids and by the decreased production of AhR ligands by microbiota that could limit indoleamine 2,3-dioxygenase induction and influence allogeneic T cell reactivity.

Graft versus host disease (GvHD) still hinders allogeneic hematopoietic stem cell transplantation. Here, the authors use metabolomics to analyze two cohorts of paired transplant recipients and donors, identifying significant differences in both host- and microbiota-derived metabolites.

Treatment with Apocynin Limits the Development of Acute Graft-versus-Host Disease in Mice

Graft-versus-host disease (GVHD) is the most serious complication limiting the clinical utility of allogeneic hematopoietic stem cell transplantation (HSCT), in which lymphocytes of donors (graft) are activated in response to the host antigen. This disease is associated with increased inflammatory response through the release of inflammatory mediators such as cytokines, chemokines, and reactive oxygen species (ROS). In this study, we have evaluated the role of ROS in GVHD pathogenesis by treatment of recipient mice with apocynin (apo), an inhibitor of intracellular translocation of cytosolic components of NADPH oxidase complex. The pharmacological blockade of NADPH oxidase resulted in prolonged survival and reduced GVHD clinical score. This reduction in GVHD was associated with reduced levels of ROS and TBARS in target organs of GVHD in apocynin-treated mice at the onset of the mortality phase. These results correlated with reduced intestinal and liver injuries and decreased levels of proinflammatory cytokines and chemokines. Mechanistically, pharmacological blockade of the NADPH oxidase was associated with inhibition of recruitment and accumulation of leukocytes in the target organs. Additionally, the chimerism remained unaffected after treatment with apocynin. Our study demonstrates that ROS plays an important role in mediating GVHD, suggesting that strategies aimed at blocking ROS production may be useful as an adjuvant therapy in patients subjected to bone marrow transplantation.

Anti-Allergic and Anti-Inflammatory Effects of Kuwanon G and Morusin on MC/9 Mast Cells and HaCaT Keratinocytes

Atopic dermatitis (AD) is a prevalent chronic inflammatory skin disease. The use of immunomodulatory corticosteroids in AD treatment causes adverse side effects. Therefore, novel natural anti-inflammatory therapeutics are needed. The aim of the present study was to investigate the anti-allergic and anti-inflammatory activities of kuwanon G and morusin. To investigate the effect of kuwanon G and morusin on skin inflammation, enzyme-linked immunosorbent assays (ELISA) to quantitate secreted (RANTES/CCL5), thymus- and activation-regulated chemokine (TARC/CCL17), and macrophage-derived chemokine (MDC/CCL22) were performed, followed by Western blotting to measure the phosphorylation of signal transducer and activator of transcription 1 (STAT1) and nuclear transcription factor-κB (NF-κB) p65 in tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ)-stimulated HaCaT keratinocytes. In order to evaluate the anti-allergic effects, ELISA to quantify histamine and leukotriene C₄ (LTC₄) production and Western blotting to measure 5-lipoxygenase (5-LO) activation were performed using PMA and A23187-stimulated MC/9 mast cells. Kuwanon G reduced the release of RANTES/CCL5, TARC/CCL17, and MDC/CCL22 via down-regulation of STAT1 and NF-κB p65 signaling in TNF-α and IFN-γ-stimulated HaCaT keratinocytes. Kuwanon G also inhibited histamine production and 5-LO activation in PMA and A23187-stimulated MC/9 mast cells. Morusin inhibited RANTES/CCL5 and TARC/CCL17 secretion via the suppression of STAT1 and NF-κB p65 phosphorylation in TNF-α and IFN-γ-stimulated HaCaT keratinocytes, and the release of histamine and LTC₄ by suppressing 5-LO activation in PMA and A23187-stimulated MC/9 mast cells. Kuwanon G and morusin are potential anti-inflammatory mediators for the treatment of allergic and inflammatory skin diseases such as AD.

Recipient-derived IL-22 alleviates murine acute graft-versus-host disease in association with reduced activation of antigen presenting cells

Acute graft-versus-host disease (aGVHD) remains a major challenging complication of patients receiving allogeneic hematopoietic cell transplantation (allo-HCT). CD4+ effector T cells and their related cytokines mediate pathogenesis of aGVHD, in which donor-T-cell derived interleukin-22 (IL-22) was recently indicated to play a role. The role of recipient-derived IL-22 in aGVHD remains to be elucidated. By applying IL-22 knock out (IL-22KO) mice as recipients of allotransplant, we found recipient derived IL-22 alleviated aGVHD and improved survival of allotransplant recipients. Knock out of IL-22 in recipient increased levels of T-helper (Th1) 1 cells but decreased levels of regulatory T cells (Tregs) in target tissues of aGVHD. Levels of IL-22 increased in aGVHD mice. Recipient antigen presenting cells (APCs) are important sources of IL-22. IL-22 reduced activation of APCs in vitro. Defect of IL-22 in APCs resulted in increased polarization of Th1 cells but decreased level of Tregs in an in vitro co-culture system. Our data highlight an immunoregulatory function of recipient-derived IL-22 in aGVHD.