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Gu BH, Kim M, Yun CH. Regulation of Gastrointestinal Immunity by Metabolites. Nutrients 2021; 13:nu13010167. [PMID: 33430497 PMCID: PMC7826526 DOI: 10.3390/nu13010167] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 01/01/2021] [Accepted: 01/04/2021] [Indexed: 12/11/2022] Open
Abstract
The gastrointestinal tract contains multiple types of immune cells that maintain the balance between tolerance and activation at the first line of host defense facing non-self antigens, including dietary antigens, commensal bacteria, and sometimes unexpected pathogens. The maintenance of homeostasis at the gastrointestinal tract requires stringent regulation of immune responses against various environmental conditions. Dietary components can be converted into gut metabolites with unique functional activities through host as well as microbial enzymatic activities. Accumulating evidence demonstrates that gastrointestinal metabolites have significant impacts on the regulation of intestinal immunity and are further integrated into the immune response of distal mucosal tissue. Metabolites, especially those derived from the microbiota, regulate immune cell functions in various ways, including the recognition and activation of cell surface receptors, the control of gene expression by epigenetic regulation, and the integration of cellular metabolism. These mucosal immune regulations are key to understanding the mechanisms underlying the development of gastrointestinal disorders. Here, we review recent advancements in our understanding of the role of gut metabolites in the regulation of gastrointestinal immunity, highlighting the cellular and molecular regulatory mechanisms by macronutrient-derived metabolites.
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Affiliation(s)
- Bon-Hee Gu
- Life and Industry Convergence Research Institute, Pusan National University, Miryang 50463, Korea;
| | - Myunghoo Kim
- Life and Industry Convergence Research Institute, Pusan National University, Miryang 50463, Korea;
- Department of Animal Science, College of Natural Resources & Life Science, Pusan National University, Miryang 50463, Korea
- Correspondence: (M.K.); (C.-H.Y.)
| | - Cheol-Heui Yun
- Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Korea
- Center for Food and Bioconvergence, Seoul National University, Seoul 08826, Korea
- Institute of Green-Bio Science and Technology, Seoul National University, Pyeongchang-gun, Gangwon-do 25354, Korea
- Correspondence: (M.K.); (C.-H.Y.)
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Smith EM, Hughes TK, Hashemi F, Stefano GB. Immunosuppressive effects of corticotropin and melanotropin and their possible significance in human immunodeficiency virus infection. Proc Natl Acad Sci U S A 1992; 89:782-6. [PMID: 1309958 PMCID: PMC48323 DOI: 10.1073/pnas.89.2.782] [Citation(s) in RCA: 61] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The activation of human granulocytes and invertebrate immunocytes was found to be suppressed by corticotropin (ACTH) and melanotropin (MSH). In spontaneously active granulocytes both neuropeptides caused significant conformational changes indicative of inactivity plus a reduction in their locomotion. Significant inactivation of human granulocytes by ACTH required 2 hr, that by MSH only 20 min. The addition to the incubation medium of phosphoramidon, a specific inhibitor of neutral endopeptidase 24.11, blocked inactivation of granulocytes by ACTH. Radioimmunoassay for MSH of supernatant fluids from granulocytes incubated with ACTH demonstrated a time-dependent increase in MSH. These data strongly indicate that the effect of ACTH is largely due to its conversion to MSH by granulocyte-associated neutral endopeptidase. Parallel experiments with immunocytes from the mollusc Mytilus edulis gave similar results, indicating the universality of this phenomenon. Our finding that the human immunodeficiency virus, among several viruses, induces ACTH and MSH production in H9 T-lymphoma cells suggests an important role of these neuropeptides in the immunosuppression characteristic of such infections.
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Affiliation(s)
- E M Smith
- Department of Psychiatry, University of Texas Medical Branch, Galveston 77550
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Abstract
The hypercorticism frequently observed in major depression, unaccompanied by signs of Cushing's syndrome, is still poorly understood. One suicidal young woman, with very high cortisol levels and unusual resistance to dexamethasone suppression, is described. She was successfully treated with steroid suppressive drugs (aminoglutethimide, metyrapone), had a prompt and complete remission and has remained well for more than two years on no medication. This success prompted an on-going clinical trial of this therapy. The available drugs and a working hypothesis of their action are discussed.
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Affiliation(s)
- B E Murphy
- Department of Medicine, McGill University, Montreal, Canada
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Lin C, Sarath G, Frank JA, Krueger RJ. Bivalent ACTH antagonists: influence of peptide and spacer components on potency enhancement. Biochem Pharmacol 1991; 41:789-95. [PMID: 1847814 DOI: 10.1016/0006-2952(91)90082-g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The antagonist potency of a series of bivalent adrenocorticotropic hormone (ACTH) peptides was examined using suspensions of inner zone rat adrenocortical cells. Bivalent antagonists were prepared by bis(maleimide) covalent cross-linking of carboxyl terminal cysteine sulfhydryl groups of synthetic ACTH peptides, Cys25 ACTH(7-25) and Cys39 ACTH(7-39). Antagonist potency enhancement was defined by shifts in ACTH(1-39) concentration-steroidogenic response curves relative to monovalent antagonist analogs. The EC50 values measured in the presence of 0.5 microM monovalent antagonist were 110 +/- 28 pM for Cys25 ACTH(7-25)-S-N-ethylsuccinimide and 44 +/- 9 pM for Cys39 ACTH(7-39)-S-N-ethylsuccinimide. Some bivalent ACTH antagonists displayed much greater antagonist potency than their monovalent analogs, which supports the findings of Stolz and Fauchere (Helv Chim Acta 71: 1421-1428, 1988). The level of potency enhancement, however, was found to be dependent upon the spacer used to link receptor binding domains and the length of the ACTH peptide used in bivalent antagonist synthesis. The most potent inhibitor, bis(Cys25 ACTH(7-25)-S-succinimidopropionyl)2-hydroxy-1,3-propanediamine, was 28 times more potent than its monovalent analog, Cys25 ACTH(7-25)-S-N-ethylsuccinimide. However, a bivalent Cys25 ACTH(7-25) peptide containing two bis(succinimidopropionyl)2-hydroxy-1,3-propanediamine spacers that had been linked end-to-end via dithioerythritol showed no potency enhancement. Cys25 ACTH(7-25) based peptides containing one receptor binding domain and having the structure peptide-spacer-cysteine displayed no enhancement in antagonist potency. Bivalent Cys39 ACTH(7-39) linked by bis(succinimidopropionyl)2-hydroxy-1,3-propanediamine spacer exhibited only 4-fold enhancement in antagonist potency relative to Cys39 ACTH(7-39)-S-N-ethylsuccinimide. We therefore conclude that the potency enhancement observed with bivalent ACTH peptides: (1) is optimal with spacers less than approximately 40 A in length, (2) is not due to direct interactions between the spacer and cell surface, and (3) is dependent on the length of the ACTH peptide component. In addition, these results indicate that electrostatic interaction between bivalent ACTH peptides and plasma membrane lipids does not adequately account for the potency enhancements observed.
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Affiliation(s)
- C Lin
- Department of Biochemistry, School of Biological Sciences, University of Nebraska, Lincoln 68585-0718
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Castro MG, Estivariz FE, Iturriza FC. The regulation of the corticomelanotropic cell activity in aves. III--Effect of various peptides on the release of MSH from dispersed, perfused duck pituitary cells. Cosecretion of ACTH with MSH. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. C, COMPARATIVE PHARMACOLOGY AND TOXICOLOGY 1988; 91:389-93. [PMID: 2905954 DOI: 10.1016/0742-8413(88)90047-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
1. The melanotropin-releasing activity of arginine-vasopressin (AVP), arginine-vasotocin (AVT), oxitocin (OT), mesotocin (MT) and corticotropin-releasing factor (CRF) was studied in the duck using dispersed, perfused pituitary cells and a specific alpha-MSH RIA. 2. Log dose-response curves were obtained for all the peptides ranging from 5 to 100 ng/ml. All peptides behaved as partial agonists compared to duck median eminence extracts (DME). 3. AVT and MT displayed an alpha-MSH releasing capacity of 60% relative to DME whereas all other peptides behaved as weak agonists with less than 15% capacity relative to DME. 4. AVT and CRF when perfused together acted synergistically on alpha-MSH release yielding a dose response line whose slope approximated that of DME. 5. ACTH was cosecreted together with alpha-MSH in all situations studied with an ACTH to alpha-MSH molar ratio of about 10. 6. It is concluded that CRF and neurohypophyseal peptides may be physiological stimulators of both alpha-MSH and ACTH release in aves.
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Affiliation(s)
- M G Castro
- Centro de Estudios Endocrinos, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, Argentina
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Castro MG, Estivariz FE, Iturriza FC. The regulation of the corticomelanotropic cell activity in Aves--II. Effect of various peptides on the release of ACTH from dispersed, perfused duck pituitary cells. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. A, COMPARATIVE PHYSIOLOGY 1986; 83:71-5. [PMID: 2868834 DOI: 10.1016/0300-9629(86)90090-3] [Citation(s) in RCA: 68] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
We have estimated the corticotropin-releasing activity (CRA) of different neurohypophyseal peptides and synthetic corticotropin-releasing factor (CRF) in the duck, using perfused dispersed pituitary cells and an ACTH radioimmunoassay adapted to duck material. Log dose-response curves were obtained for different doses of arginine-vasopressin (AVP), arginine-vasotocin (AVT), mesotocin (MT), oxitocin (OT) and ovine CRF (oCRF) and compared to the response obtained with dilutions of duck median eminence extracts (DME). All peptides tested behaved as partial agonists compared to DME. AVT and MT were the most potent of all peptides tested, with a capacity of 60% relative to DME. CRF was a weak agonist together with AVP and OT. AVT and CRF perfused together at equal doses significantly potentiated the effect of each other, yielding a dose-response line whose slope approximated that of DME. A similar design was used to test the CRA of the same substances in the rat. The main difference in the pattern of response between the two species was the low potency displayed by all the neurohypophyseal peptides in the rat, compared with CRF which, in contrast with what occurred with the duck system, was the most potent secretagogue of all peptides tested. It is concluded that in birds, as in mammals, the control of ACTH secretion may be exerted by neurohypophyseal peptides and a CRF-like peptide acting synergistically upon the corticomelanotropic cell.
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Szalay KS, De Wied D, Stark E, Folly G. Structure-activity studies with ACTH/alpha-MSH fragments on corticosteroid secretion of isolated zona glomerulosa and fasciculata cells. REGULATORY PEPTIDES 1985; 11:187-92. [PMID: 2997858 DOI: 10.1016/0167-0115(85)90049-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The steroidogenic action of ACTH/alpha-MSH fragments was studied on isolated zona glomerulosa and zona fasciculata cells dispersed by collagenase. ACTH-(4-7), ACTH-(6-10), ACTH-(4-10) and ACTH-(11-13) stimulated corticosterone production of the zona fasciculata and aldosterone production of the zona glomerulosa cells. ACTH-(7-10) was ineffective. ACTH-(4-7) appeared to be the most potent peptide of the tested fragments. None of the fragments affected the steroidogenic action of ACTH-(1-39). It is suggested that similar to the melanotropic effect of alpha-MSH two 'message' sequences for adrenocortical stimulation exist in the alpha-MSH part of the ACTH molecule.
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Buckingham JC, Leach JH, Plisetskaya E, Sower SA, Gorbman A. Corticotrophin-like bioactivity in the pituitary gland and brain of the pacific hagfish, Eptatretus stouti. Gen Comp Endocrinol 1985; 57:434-7. [PMID: 2985463 DOI: 10.1016/0016-6480(85)90225-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The cytochemical bioassay for corticotrophin (ACTH) was used in an attempt to detect ACTH-like activity in the Pacific hagfish, Eptatretus stouti. Extracts of the pituitary gland and brain were active in this assay system but those of liver and skeletal muscles were not. The slopes of the dose-response lines of the pituitary extracts were less than those of the mammalian corticotrophin standard preparation but greater than those of the brain extracts. The results suggest that the corticotrophic factor in the hagfish differs from mammalian ACTH.
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Carsia RV, Scanes CG, Malamed S. Isolated adrenocortical cells of the domestic fowl (Gallus domesticus): steroidogenic and ultrastructural properties. JOURNAL OF STEROID BIOCHEMISTRY 1985; 22:273-9. [PMID: 2984470 DOI: 10.1016/0022-4731(85)90124-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Isolated adrenocortical cells from White Leghorn chickens (Gallus domesticus) were compared to those from rats (Rattus norvegicus). Cells were prepared from collagenase-dispersed adrenal glands of sexually mature male animals. Corticosterone was measured by radioimmunoassay after incubation for 2 h with steroidogenic agents. Of the four ACTH analogues used, three were 6-17 times more potent with rat cells than with fowl cells (potencies were indicated by half-maximal steroidogenic concentrations). However, 9-tryptophan (O-nitrophenylsulfenyl) ACTH was 8 times more potent with fowl cells than with rat cells, thus suggesting that ACTH receptor differences exist between the two cell types. In addition, cAMP analogues were 10 times more potent with rat cells than with fowl cells suggesting that fowl corticosteroidogenesis is less dependent on cAMP than is rat corticosteroidogenesis. At equal cell concentrations, rat cells secreted 20-40 times more corticosterone than did chicken cells when they were maximally stimulated. Although rat cells converted 8 times more pregnenolone to corticosterone than did fowl cells, the half-maximal steroidogenic concentration for pregnenolone-supported corticosterone synthesis was the same for both cell types (about 5 microM). This suggests that fowl cells have lower steroidogenic enzyme content rather than lower steroidogenic enzyme activity. An unusual feature seen in the isolated fowl adrenocortical cells was an abundance of intracellular filaments.
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Baker BI, Buckingham JC. A study of corticotrophic and melanotrophic activities in the pituitary and brain of the lamprey Lampetra fluviatilis. Gen Comp Endocrinol 1983; 52:283-90. [PMID: 6317514 DOI: 10.1016/0016-6480(83)90124-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Biological and radioimmunological assay methods were used in an attempt to detect and determine corticotrophic and melanotrophic activity in the pituitary gland and the central nervous system of the lamprey, Lampetra fluviatilis. The activities of various corticotrophin (1-39 ACTH)-related peptides in the cytochemical assay for ACTH could be readily distinguished on the basis of their dose-response lines. Extracts of the pituitary gland and brain but not of spinal cord were also active in this test. The dose-response lines of the pars distalis extracts were parallel with those of 1-39 ACTH; those of the neurointermediate lobe and the brain resembled des-Ac-alpha-MSH and alpha-MSH, respectively, although subsequent tests showed that the active molecules in the extracts differed from these standard peptides in other respects. Pituitary extracts were active in the Anolis bioassay for melanotrophin but not in a radioimmunoassay for alpha-MSH. Moreover, the electrophoretic Rf value of lamprey melanotrophic activity was distinct from both alpha-MSH and des-Ac-alpha-MSH. Brain extracts showed only low melanotrophic bioactivity and again no immunoreactivity. The results suggest that small amounts of corticotrophin occur in the pars distalis of the lamprey and that the melanotrophic factors in the neurointermediate lobe and brain are not identical to mammalian alpha-MSH and des-Ac-alpha-MSH.
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Crivello JF, Jefcoate CR. Mechanisms of corticotropin action in rat adrenal cells. I. The effects of inhibitors of protein synthesis and of microfilament formation on corticosterone synthesis. Biochim Biophys Acta Gen Subj 1978; 542:315-29. [PMID: 210838 DOI: 10.1016/0304-4165(78)90027-2] [Citation(s) in RCA: 97] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The contributions of protein synthesis and formation of microtubules and microfilaments to corticotropin-stimulated steroidogenesis in rat adrenal cell suspensions has been assessed by use of a series of inhibitors to each function. Five inhibitors of protein synthesis (cycloheximide, puromycin, blastocidin S, anisomycin, and trichodermin) each exhibited time-dependent inhibition of corticotropin-stimulated steroidogenesis. For the first 30 min, steroidogenesis was more extensively inhibited than protein synthesis, after which the effectiveness of the inhibitors diminished on steroidogenesis but not on protein synthesis. The reversal effect was not observed at high levels of inhibitors. One inhibitor of microfilament formation (cytochalasin B) and four inhibitors of microtubule formation (colchicine, podophyllotoxin, vinblastine sulfate and griseofulvin) inhibited steroidogenesis without inhibiting protein synthesis and without any reversal effect with prolonged incubation. The actions of all ten inhibitors were shown to be fully reversible. Cell superfusion of adrenal cells showed that the decay of steroidogenesis upon addition of all the protein synthesis inhibitors was similar to decay upon removal of corticotropin from the medium (t1/2 = 4--6 min). Recoveries from inhibition upon removal of the inhibitors were similar to each other and comparable to initial corticotropin stimulation of the cells (lag of 3--5 min, t1/2=7--9 min). Similar kinetics of inhibition and recovery were observed for vinblastine sulfate while a direct inhibition of cytochrome P-450scc by aminoglutethimide was complete within 1 min and was rapidly reversed. Injection of each inhibitor (all classes) into hypophysectomized rats inhibited the elevation of plasma corticosterone by corticotropin. The extent of cholesterol combination with cytochrome P-450scc in adrenal mitochondria isolated from these rats was also decreased by all of the inhibitors. Decreases in plasma corticosterone correlated directly with decreases in cholesterol combination with cytochrome P-450scc (r=0.94). It is concluded that protein synthesis and steroidogenesis must be intimately coupled probably due to the requirement of a labile protein for cholesterol transport to cytochrome P-450scc. An involvement of microtubules and microfilaments in this process is clearly indicated.
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Sayers G. Bioassay of ACTH using isolated cortex cells. Applications: structure activity relationship for ACTH and analogues, assay of corticotropin-releasing factor, and assay of plasma ACTH. Ann N Y Acad Sci 1977; 297:220-41. [PMID: 211900 DOI: 10.1111/j.1749-6632.1977.tb41856.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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