ABSTRACT
The polarization of leukocytes toward chemoattractants is essential for the directed migration (chemotaxis) of leukocytes. How leukocytes acquire polarity after encountering chemical gradients is not well understood. We found here that leukocyte polarity was generated by TIPE2 (TNFAIP8L2), a transfer protein for phosphoinositide second messengers. TIPE2 functioned as a local enhancer of phosphoinositide-dependent signaling and cytoskeleton remodeling, which promoted leading-edge formation. Conversely, TIPE2 acted as an inhibitor of the GTPase Rac, which promoted trailing-edge polarization. Consequently, TIPE2-deficient leukocytes were defective in polarization and chemotaxis, and TIPE2-deficient mice were resistant to leukocyte-mediated neural inflammation. Thus, the leukocyte polarizer is a dual-role phosphoinositide-transfer protein and represents a potential therapeutic target for the treatment of inflammatory diseases.
Subject(s)
Chemotaxis, Leukocyte/genetics , Encephalomyelitis, Autoimmune, Experimental/immunology , Intracellular Signaling Peptides and Proteins/genetics , T-Lymphocytes/immunology , Animals , Cell Polarity/genetics , Chemotaxis, Leukocyte/physiology , Inflammation/genetics , Inflammation/immunology , Mice , Mice, Inbred C57BL , Mice, Knockout , Phosphatidylinositols/metabolism , Phosphotransferases (Alcohol Group Acceptor)/metabolism , Signal Transduction/genetics , Signal Transduction/physiology , rac GTP-Binding Proteins/antagonists & inhibitorsABSTRACT
Intestinal ischemia has a wide variety of causes, including, but not limited to, atherosclerosis, thrombosis, hypotension, and chronic inflammation. In severe cases, ischemic injury can result in death. µ-Opioid receptor (MOR) signaling has previously been shown to protect against chemically induced colitis, but the cellular origin of this effect remains unknown. Herein, we evaluated the role of intestinal epithelial cell (IEC)-derived MOR signaling in host responses to ischemia/reperfusion-induced injury. Ileal ischemia was accomplished through obstruction of the distal branches of the superior mesenteric artery (60 minutes) and reperfusion for 90 minutes (ischemia-reperfusion). Floxed-MOR mice were crossed to Villin-cre transgenic mice to selectively delete the MOR gene in IECs (MOR(IEC-/-)). Radio-ligand binding assays demonstrated selective loss of MOR signaling in IECs of MOR(IEC-/-) mice. The s.c. administration of the MOR agonist, [D-Arg2, Lys4] dermorphin (1-4) amide (DALDA), 10 minutes before surgery protected against both ischemic and reperfusion phases of intestinal injury, an effect abolished in MOR(IEC-/-) mice. This cytoprotective effect was associated with enterocyte-mediated phosphoinositide 3-kinase (PI3K)/glycogen synthase kinase 3ß signaling and decreased apoptosis, as determined by IHC and caspase-3 processing. PI3K blockade with Ly294002 resulted in loss of MOR-mediated cytoprotective function. Together, these data show that IEC-derived µ-opioid signaling uses the PI3K pathway to protect cells against the damaging effect of ischemia-reperfusion. Targeting MOR signaling may represent a novel mean to alleviate intestinal injury and promote the wound-healing response.
Subject(s)
Epithelial Cells/pathology , Intestines/pathology , Phosphatidylinositol 3-Kinases/metabolism , Receptors, Opioid, mu/metabolism , Reperfusion Injury/enzymology , Reperfusion Injury/prevention & control , Signal Transduction , Animals , Apoptosis/drug effects , Cytoprotection/drug effects , Enterocytes/metabolism , Enterocytes/pathology , Epithelial Cells/drug effects , Epithelial Cells/enzymology , Gene Deletion , Glycogen Synthase Kinase 3/metabolism , Glycogen Synthase Kinase 3 beta , Intestines/blood supply , Ligands , Mice , Mice, Inbred C57BL , Oligopeptides/administration & dosage , Oligopeptides/pharmacology , Organ Specificity/drug effects , Phosphorylation/drug effects , Protective Agents/pharmacology , Reperfusion Injury/pathology , Signal Transduction/drug effectsABSTRACT
Tissue infiltration by circulating leukocytes via directed migration (also referred to as chemotaxis) is a common pathogenic mechanism of inflammatory diseases. G protein-coupled receptors (GPCRs) are essential for sensing chemokine gradients and directing the movement of leukocytes during immune responses. The tumor necrosis factor α-induced protein 8-like (TIPE or TNFAIP8L) family of proteins are newly described pilot proteins that control directed migration of murine leukocytes. However, how leukocytes integrate site-specific directional cues, such as chemokine gradients, and utilize GPCR and TIPE proteins to make directional decisions are not well understood. Using both gene knockdown and biochemical methods, we demonstrated here that 2 human TIPE family members, TNFAIP8 and TIPE2, were essential for directed migration of human CD4+ T cells. T cells deficient in both of these proteins completely lost their directionality. TNFAIP8 interacted with the Gαi subunit of heterotrimeric (α, ß, γ) G proteins, whereas TIPE2 bound to PIP2 and PIP3 to spatiotemporally control immune cell migration. Using deletion and site-directed mutagenesis, we established that Gαi interacted with TNFAIP8 through its C-terminal amino acids, and that TIPE2 protein interacted with PIP2 and PIP3 through its positively charged amino acids on the α0 helix and at the grip-like entrance. We also discovered that TIPE protein membrane translocation (i.e. crucial for sensing chemokine gradients) was dependent on PIP2. Collectively, our work describes a new mechanistic paradigm for how human T cells integrate GPCR and phospholipid signaling pathways to control directed migration. These findings have implications for therapeutically targeting TIPE proteins in human inflammatory and autoimmune diseases.
Subject(s)
Second Messenger Systems , Signal Transduction , Humans , Animals , Mice , Chemokines , Amino Acids , Lipids , Intracellular Signaling Peptides and ProteinsSubject(s)
Inflammatory Bowel Diseases , Opiate Alkaloids , Short Bowel Syndrome , England , Enterocytes , HumansABSTRACT
Opiates have long been used as analgesics to relieve pain associated with various medical conditions. Here, we evaluated the effect and mechanism of mu opioid signaling on the intestinal wound healing response and assessed downstream pathways known to be protective against intestinal injury. Mice (C57BL/6) were exposed to 3% dextran sodium sulfate (DSS) for 7 days or 4% DSS for 5 days followed by 7 days of water. The mu opioid receptor (MOR)-specific agonist [D-Arg2,Lys4]dermorphin-(1,4)-amide (DALDA) and the antagonist cyprodime were injected s.c. daily for in vivo studies or used for in vitro analysis. We found that MOR activation attenuated DSS-induced histologic and gross intestinal injury and weight loss; diminished Ifng, Tnf, and Il6 mRNA expression; and promoted intestinal healing during recovery. DALDA also enhanced colonocyte proliferation (Ki-67 staining) by 350%. MOR activation increased Stat3 phosphorylation in both DALDA-treated mice and the CMT-93 cell line. Importantly, DALDA-induced colonocyte migration was completely ablated by shStat3 knockdown. Together, this work shows that MOR activation protects against and enhances recovery from DSS-induced intestinal injury. This is associated with an increase in Stat3 activation. Furthermore, Stat3 is required for DALDA-induced colonocyte migration. Consequently, manipulation of MOR signaling may represent a novel means to promote mucosal healing and to maintain intestinal homeostasis after intestinal injury.
Subject(s)
Intestines/injuries , Receptors, Opioid, mu/metabolism , STAT3 Transcription Factor/metabolism , Animals , Cell Proliferation , Colon/cytology , Dextran Sulfate/pharmacology , Homeostasis , Ki-67 Antigen/biosynthesis , Mice , Mice, Inbred C57BL , Mice, Transgenic , NF-kappa B/genetics , Oligopeptides/pharmacology , Signal Transduction , Time FactorsABSTRACT
BACKGROUND: Colorectal cancer (CRC) is the third leading cause of cancer in the United States, and inflammatory bowel disease patients have an increased risk of developing CRC due to chronic intestinal inflammation with it being the cause of death in 10% to 15% of inflammatory bowel disease patients. TIPE2 (TNF-alpha-induced protein 8-like 2) is a phospholipid transporter that is highly expressed in immune cells and is an important regulator of immune cell function. METHODS: The azoxymethane/dextran sulfate sodium murine model of colitis-associated colon cancer (CAC) was employed in Tipe2 -/- and wild-type mice, along with colonoid studies, to determine the role of TIPE2 in CAC. RESULTS: Early on, loss of TIPE2 led to significantly less numbers of visible tumors, which was in line with its previously described role in myeloid-derived suppressor cells. However, as time went on, loss of TIPE2 promoted tumor progression, with larger tumors appearing in Tipe2 -/- mice. This was associated with increased interleukin-22/STAT3 phosphorylation signaling. Similar effects were also observed in primary colonoid cultures, together demonstrating that TIPE2 also directly regulated colonocytes in addition to immune cells. CONCLUSIONS: This work demonstrates that TIPE2 has dual effects in CAC. In the colonocytes, it works as a tumor suppressor. However, in the immune system, TIPE2 may promote tumorigenesis through suppressor cells or inhibit it through IL-22 secretion. Going forward, this work suggests that targeting TIPE2 for CRC therapy requires cell- and pathway-specific approaches and serves as a cautionary tale for immunotherapy approaches in general in terms of colon cancer, as intestinal inflammation can both promote and inhibit cancer.
TIPE2 (TNF-alpha-induced protein 8-like 2) regulates immune function. Here, we find that it differentially regulates the initiation and progression of its immunoregulatory properties affect murine colitis-associated colon cancer initiation and progression. Surprisingly, we found that TIPE2 a novel tumor suppressor in enterocytes, a cell compartment it was not previously known to directly regulate.
Subject(s)
Colitis-Associated Neoplasms , Colitis , Inflammatory Bowel Diseases , Animals , Azoxymethane/toxicity , Cell Transformation, Neoplastic/pathology , Colitis/chemically induced , Colitis/complications , Colitis-Associated Neoplasms/genetics , Colon/pathology , Dextran Sulfate/toxicity , Disease Models, Animal , Inflammation/pathology , Inflammatory Bowel Diseases/complications , Intracellular Signaling Peptides and Proteins/genetics , Mice , Mice, Inbred C57BLABSTRACT
The intestine is a highly proliferative dynamic environment that relies on constant self-renewal of the intestinal epithelium to maintain homeostasis. Tumor necrosis factor-alpha-induced protein 8 (TNFAIP8 or TIPE0) is a regulator of PI3K-mediated signaling. By binding to PIP2 and PIP3, TIPE family members locally activate PI3K activity while globally inhibiting PI3K activity through sequestration of membranous PIP2. Single-cell RNA sequencing survey of Tipe0-/- small intestine was used to investigate the role of TIPE0 in intestinal differentiation. Tipe0-/- intestinal cells were shown to shift towards an undifferentiated state, with the notable exception of goblet cells. Additionally, three possible novel regulators of terminal cell fate decisions in the secretory lineage were identified: Nupr1, Kdm4a, and Gatad1. We propose that these novel regulators drive changes involved in goblet cell (Nupr1) or tuft cell (Kdm4a and Gatad1) fate commitment and that TIPE0 may play a role in orchestrating terminal differentiation.
Subject(s)
Apoptosis Regulatory Proteins/metabolism , Cell Differentiation , Epithelial Cells/cytology , Intestinal Mucosa/cytology , Stem Cells/cytology , Animals , Apoptosis Regulatory Proteins/deficiency , Cell Lineage , Epithelial Cells/metabolism , Gene Expression Profiling , Gene Expression Regulation , Mice, Inbred C57BL , Stem Cells/metabolismABSTRACT
Cancer metastasis accounts for nearly 90% of all cancer deaths. Metastatic cancer progression requires both cancer cell migration to the site of the metastasis and subsequent proliferation after colonization. However, it has long been recognized that cancer cell migration and proliferation can be uncoupled; but the mechanism underlying this paradox is not well understood. Here we report that TNFAIP8 (tumor necrosis factor-α-induced protein 8), a "professional" transfer protein of phosphoinositide second messengers, promotes cancer cell migration or metastasis but inhibits its proliferation or cancer growth. TNFAIP8-deficient mice developed larger tumors, but TNFAIP8-deficient tumor cells completely lost their ability to migrate toward chemoattractants and were defective in colonizing lung tissues as compared to wild-type counterparts. Mechanistically, TNFAIP8 served as a cellular "pilot" of tumor cell migration by locally amplifying PI3K-AKT and Rac signals on the cell membrane facing chemoattractant; at the same time, TNFAIP8 also acted as a global inhibitor of tumor cell growth and proliferation by regulating Hippo signaling pathway. These findings help explain the migration-proliferation paradox of cancer cells that characterizes many cancers.
Subject(s)
Apoptosis Regulatory Proteins/metabolism , Fibrosarcoma/pathology , Lung Neoplasms/pathology , Skin Neoplasms/pathology , Animals , Apoptosis Regulatory Proteins/genetics , Cell Line, Tumor , Cell Movement , Cell Proliferation , Diethylnitrosamine/adverse effects , Female , Fibrosarcoma/chemically induced , Fibrosarcoma/genetics , Fibrosarcoma/metabolism , Gene Expression Regulation, Neoplastic , Hippo Signaling Pathway , Humans , Lung Neoplasms/chemically induced , Lung Neoplasms/genetics , Lung Neoplasms/metabolism , Male , Methylcholanthrene/adverse effects , Mice , Phosphatidylinositol 3-Kinases/metabolism , Skin Neoplasms/chemically induced , Skin Neoplasms/genetics , Skin Neoplasms/metabolismSubject(s)
Adjuvants, Immunologic/therapeutic use , Analgesics, Opioid/therapeutic use , Crohn Disease/drug therapy , Drug Tolerance , Granulocyte-Macrophage Colony-Stimulating Factor/therapeutic use , Immunosuppressive Agents , Loperamide/therapeutic use , Adolescent , Crohn Disease/immunology , Female , Humans , Immunosuppressive Agents/therapeutic use , Remission InductionABSTRACT
Genome-wide association studies have established that human REL is a susceptibility gene for lymphoid cancers and inflammatory diseases. REL is the hematopoietic member of the nuclear factor-κB (NF-κB) family and is frequently amplified in human lymphomas. However, the mechanism through which REL and its encoded protein c-Rel affect human lymphoma is largely unknown. Using both loss-of-function and gain-of-function approaches, we studied the roles of REL gene in human Jurkat leukemia cells. Compared with control Jurkat cells, REL knockout cells exhibited significant defects in cell growth and mitochondrial respiration. Genome-wide transcriptome analyses revealed that T cells lacking c-Rel had selective defects in the expression of inflammatory and metabolic genes including c-Myc. We found that c-Rel controlled the expression of c-Myc through its promotor, and expressing c-Myc in c-Rel-deficient lymphoma cells rescued their proliferative and metabolic defects. Thus, the human c-Rel-c-Myc axis controls lymphoma growth and metabolism and could be a therapeutic target for lymphomas.
Subject(s)
Cell Proliferation/physiology , Leukemia, T-Cell/metabolism , Leukemia, T-Cell/pathology , Proto-Oncogene Proteins c-myc/metabolism , Proto-Oncogene Proteins c-rel/metabolism , Gene Knockout Techniques , Humans , Jurkat CellsABSTRACT
Lymphocytes are some of the most motile cells of vertebrates, constantly navigating through various organ systems. Their specific positioning in the body is delicately controlled by site-specific directional cues such as chemokines. While it has long been suspected that an intrinsic molecular pilot, akin to a ship's pilot, guides lymphocyte navigation, the nature of this pilot is unknown. Here we show that the TIPE (TNF-α-induced protein 8-like) family of proteins pilot lymphocytes by steering them toward chemokines. TIPE proteins are carriers of lipid second messengers. They mediate chemokine-induced local generation of phosphoinositide second messengers, but inhibit global activation of the small GTPase Rac. TIPE-deficient T lymphocytes are completely pilot-less: they are unable to migrate toward chemokines despite their normal ability to move randomly. As a consequence, TIPE-deficient mice have a marked defect in positioning their T lymphocytes to various tissues, both at the steady-state and during inflammation. Thus, TIPE proteins pilot lymphocytes during migration and may be targeted for the treatment of lymphocyte-related disorders.
Subject(s)
Cell Movement , Health , Inflammation/pathology , Intracellular Signaling Peptides and Proteins/metabolism , T-Lymphocytes/pathology , Animals , Apoptosis Regulatory Proteins/deficiency , Apoptosis Regulatory Proteins/metabolism , Chemokines/pharmacology , Encephalomyelitis, Autoimmune, Experimental/metabolism , Encephalomyelitis, Autoimmune, Experimental/pathology , Guanosine Triphosphate/metabolism , Intracellular Signaling Peptides and Proteins/deficiency , Mice, Inbred C57BL , Mice, Knockout , Models, Biological , Nervous System/pathology , Phosphatidylinositol 3-Kinases/metabolism , Phosphatidylinositol Phosphates/metabolism , Second Messenger Systems , rac GTP-Binding Proteins/metabolismABSTRACT
The intestine is a highly dynamic environment that requires tight control of the various inputs to maintain homeostasis and allow for proper responses to injury. It was recently found that the stem cell niche and epithelium is regenerated after injury by de-differentiated adult cells, through a process that gives rise to Sca1+ fetal-like cells and is driven by a transient population of Clu+ revival stem cells (revSCs). However, the molecular mechanisms that regulate this dynamic process have not been fully defined. Here we show that TNFAIP8 (also known as TIPE0) is a regulator of intestinal homeostasis that is vital for proper regeneration. TIPE0 functions through inhibiting basal Akt activation by the commensal microbiota via modulating membrane phospholipid abundance. Loss of TIPE0 in mice results in injury-resistant enterocytes, that are hyperproliferative, yet have regenerative deficits and are shifted towards a de-differentiated state. Tipe0-/- enterocytes show basal induction of the Clu+ regenerative program and a fetal gene expression signature marked by Sca1, but upon injury are unable to generate Sca-1+/Clu+ revSCs and could not regenerate the epithelium. This work demonstrates the role of TIPE0 in regulating the dynamic signaling that determines the injury response and enables intestinal epithelial cell regenerative plasticity.
Subject(s)
Apoptosis Regulatory Proteins/metabolism , Gastrointestinal Microbiome/physiology , Intestines/cytology , Proto-Oncogene Proteins c-akt/metabolism , Animals , Apoptosis Regulatory Proteins/genetics , Ataxin-1/metabolism , Cell Differentiation , Colitis/chemically induced , Colitis/pathology , Enterocytes/pathology , Female , Gene Knockdown Techniques , Homeostasis , Intestines/blood supply , Intestines/pathology , Intestines/radiation effects , Ischemia/genetics , Ischemia/pathology , Leukocyte Common Antigens/metabolism , Male , Mice, Inbred C57BL , Radiation Injuries, Experimental/pathology , Regeneration/physiology , Signal Transduction , Stem Cell Niche , Stem Cells/metabolismABSTRACT
OBJECTIVES: To switch patients with ulcerative colitis (UC) from costlier 5-aminosalicylic acid compounds to sulfasalazine and assess (1) the cost savings, (2) the barriers to switching, and (3) adverse events (AEs) and adherence at 3 months after the drug switch. STUDY DESIGN: An open-label, pharmacist-administered drug switch program coordinated at an academic inflammatory bowel disease center. METHODS: A clinical pharmacist contacted patients with UC who were prescreened by physicians and covered by specific insurers to enroll them in the drug switch program. Enrolled patients were followed for 3 months to assess AEs and medication adherence. Reasons for declining to participate were recorded. RESULTS: A total of 205 eligible patients were identified; only 14 enrolled, and 10 remained on sulfasalazine for the entire 3-month follow-up period. The enrollment rate was only 4.9%, yet a net cost savings of $22,828/3-month to the insurer was achieved (including program administration costs but excluding AE costs), with co-pays reduced by approximately $25 per month per patient. The rate of AEs on sulfasalazine (28.6%) was similar to that found in previous reports. Significant unanticipated barriers to switching were encountered, namely patient desire to not alter an existing effective drug regimen. CONCLUSIONS: A pharmacist-administered drug switch program in patients with UC was significantly more difficult than anticipated, with questionable achievement of cost savings. This experience suggests that future drug switches and studies should focus on patient preferences for drug switching, as this may have implications for switching from brand name to biosimilar drugs.
Subject(s)
Aminosalicylic Acids/economics , Colitis, Ulcerative/drug therapy , Cost Savings , Drug Substitution/economics , Sulfasalazine/economics , Sulfasalazine/therapeutic use , Administration, Oral , Adolescent , Adult , Aminosalicylic Acids/therapeutic use , Cohort Studies , Colitis, Ulcerative/diagnosis , Colitis, Ulcerative/economics , Female , Humans , Male , Program Evaluation , Retrospective Studies , United States , Young AdultABSTRACT
This corrects the article DOI: 10.1038/cmi.2017.4.
ABSTRACT
The TIPE (tumor necrosis factor-α-induced protein 8-like) family are newly described regulators of immunity and tumorigenesis consisting of four highly homologous mammalian proteins: TNFAIP8 (tumor necrosis factor-α-induced protein 8), TIPE1 (TNFAIP8-like 1, or TNFAIP8L1), TIPE2 (TNFAIP8L2) and TIPE3 (TNFAIP8L3). They are the only known transfer proteins of the lipid secondary messengers PIP2 (phosphatidylinositol 4,5-bisphosphate) and PIP3 (phosphatidylinositol 3,4,5-trisphosphate). Cell-surface receptors, such as G-protein-coupled receptors and receptor tyrosine kinases, regulate inflammation and cancer via several signaling pathways, including the nuclear factor (NF)-κB and phosphoinositide-3 kinase (PI3K) pathways, the latter of which is upstream of both Akt and STAT3 activation. An expression analysis in humans demonstrated that the TIPE family is dysregulated in cancer and inflammation, and studies both in mice and in vitro have demonstrated that this family of proteins plays a critical role in tumorigenesis and inflammatory responses. In this review, we summarize the current literature for all four family members, with a special focus on the phenotypic manifestations present in the various knockout murine strains, as well as the related cell signaling that has been elucidated to date.
Subject(s)
Carcinogenesis/metabolism , Inflammation/metabolism , Intracellular Signaling Peptides and Proteins/metabolism , Phospholipid Transfer Proteins/metabolism , Tumor Necrosis Factor-alpha/metabolism , Animals , Humans , Intracellular Signaling Peptides and Proteins/genetics , Mice , Mice, Knockout , Models, Animal , Phospholipid Transfer Proteins/genetics , Receptors, G-Protein-Coupled/metabolism , Signal TransductionABSTRACT
This chapter describes a method to assay compounds modulating NSAID-induced intestinal injury in zebrafish larvae. The assay employs the NSAID glafenine, which causes intestinal epithelial cell damage and death by inducing organelle stress responses (endoplasmic reticulum and mitochondrial) and blocking the unfolded protein response pathway. This epithelial damage includes sloughing of intestinal cells into the lumen and out the cloaca of the zebrafish larvae. Exposing larvae to acridine orange highlights this injury when visualized under fluorescence microscope; injured fish develop intensely red-staining intestines, as well as a "tube" or cord of red color extending through the intestine and out the cloaca. Using this rapid visually screenable method, various candidate compounds were successfully tested for their ability to prevent glafenine-induced intestinal injury. Because this assay involves examination of larval zebrafish intestinal pathology, we have also included our protocol for preparation and analysis of zebrafish histology. The protocol includes numerous steps to generate high-quality zebrafish histology slides, as well as protocols to establish accurate anatomic localization of any given tissue cross-section-processes that are made technically difficult by the small size of zebrafish larvae.
Subject(s)
Intestines/drug effects , Intestines/injuries , Protective Agents/pharmacology , Zebrafish/growth & development , Animals , Disease Models, Animal , Drug Evaluation, Preclinical , Endoplasmic Reticulum Stress/drug effects , Glafenine/toxicity , Intestinal Diseases/chemically induced , Intestinal Diseases/prevention & control , LarvaABSTRACT
Vitamin D refers to a class of fat-soluble secosteroids often associated with their role in absorption and metabolism of minerals such as calcium and phosphate. In recent years, our understanding of vitamin D has expanded to include its role in modulating the immune system. Of particular focus are the effects of vitamin D deficiency and supplementation on patients suffering from disorders due to dysregulation of the immune system. In patients with multiple sclerosis, rheumatoid arthritis, and inflammatory bowel disease, deficiencies in vitamin D have been associated with an increased risk of disease activity. In this review, we will look at the current state of research in regards to the relationship between vitamin D and immune-dysregulation. We will focus on both the risks associated with vitamin D deficiency as well as the benefits of vitamin D supplementation.
ABSTRACT
Dietary impacts on health may be one of the oldest concepts in medicine; however, only in recent years have technical advances in mass spectroscopy, gnotobiology, and bacterial sequencing enabled our understanding of human physiology to progress to the point where we can begin to understand how individual dietary components can affect specific illnesses. This review explores the current understanding of the complex interplay between dietary factors and the host microbiome, concentrating on the downstream implications on host immune function and the pathogenesis of disease. We discuss the influence of the gut microbiome on body habitus and explore the primary and secondary effects of diet on enteric microbial community structure. We address the impact of consumption of non-digestible polysaccharides (prebiotics and fiber), choline, carnitine, iron, and fats on host health as mediated by the enteric microbiome. Disease processes emphasized include non-alcoholic fatty liver disease/non-alcoholic steatohepatitis, IBD, and cardiovascular disease/atherosclerosis. The concepts presented in this review have important clinical implications, although more work needs to be done to develop fully and validate potential therapeutic approaches. Specific dietary interventions offer exciting potential for nontoxic, physiologic ways to alter enteric microbial structure and metabolism to benefit the natural history of many intestinal and systemic disorders.
Subject(s)
Diet , Intestines/microbiology , Microbiota , Animals , Gastrointestinal Tract/metabolism , Gastrointestinal Tract/microbiology , Gastrointestinal Tract/physiopathology , Humans , Immune System/metabolism , Intestinal Mucosa/metabolism , Intestines/physiopathology , Mass Spectrometry/methodsABSTRACT
Beside their analgesic properties, opiates exert beneficial effects on the intestinal wound healing response. In this study, we investigated the role of µ-opioid receptor (MOR) signaling on the unfolded protein response (UPR) using a novel zebrafish model of NSAID-induced intestinal injury. The NSAID glafenine was administered to zebrafish larvae at 5 days post-fertilization (dpf) for up to 24 hours in the presence or absence of the MOR-specific agonist DALDA. By analysis with histology, transmission electron microscopy and vital dye staining, glafenine-treated zebrafish showed evidence of endoplasmic reticulum and mitochondrial stress, with disrupted intestinal architecture and halted cell stress responses, alongside accumulation of apoptotic intestinal epithelial cells in the lumen. Although the early UPR marker BiP was induced with glafenine-induced injury, downstream atf6 and s-xbp1 expression were paradoxically not increased, explaining the halted cell stress responses. The µ-opioid agonist DALDA protected against glafenine-induced injury through induction of atf6-dependent UPR. Our findings show that DALDA prevents glafenine-induced epithelial damage through induction of effective UPR.
Subject(s)
Activating Transcription Factor 6/metabolism , Anti-Inflammatory Agents, Non-Steroidal/toxicity , Glafenine/toxicity , Intestines/drug effects , Intestines/injuries , Receptors, Opioid, mu/metabolism , Zebrafish Proteins/metabolism , Animals , Apoptosis/drug effects , Disease Models, Animal , Endoplasmic Reticulum Chaperone BiP , Heat-Shock Proteins/metabolism , Intestinal Mucosa/drug effects , Intestinal Mucosa/injuries , Intestinal Mucosa/metabolism , Intestinal Mucosa/pathology , Intestines/pathology , Oligopeptides/pharmacology , Receptors, Opioid, mu/agonists , Signal Transduction/drug effects , Stress, Physiological , Unfolded Protein Response/drug effects , ZebrafishABSTRACT
Oxymatrine is a traditional Chinese herbal product that exhibits anti-inflammatory effects in models of heart, brain and liver injury. We investigated the impact of oxymatrine in an acute model of intestinal injury and inflammation. Oxymatrine significantly decreased LPS-induced NF-κB-driven luciferase activity, correlating with diminished induction of Cxcl2, Tnfα and Il6 mRNA expression in rat IEC-6 and murine BMDC. Although oxymatrine decreased LPS-induced p65 nuclear translocation and binding to the Cxcl2 gene promoter, this effect was independent of IκBα degradation/phosphorylation. DSS-induced weight loss and histological damage were ameliorated in oxymatrine-treated C57BL/6-WT-mice. While this effect correlated with reduced colonic Il6 and Il1ß mRNA accumulation, global NF-κB activity as measured in NF-κB(EGFP) mice was unaffected. Our data demonstrate that oxymatrine reduces LPS-induced NF-κB nuclear translocation and activity independently of IκBα status, prevents intestinal inflammation through blockade of inflammatory signaling and ameliorates overall intestinal inflammation in vivo.