Inflammatory Mediators Cytokines Research Articles

Camellia sinensis L. Extract Suppresses Inflammation on Acute Respiratory Distress Syndrome Cells Models via Decreasing IL-1ß, IL-6 and COX-2 Expressions

Acute Respiratory Distress Syndrome (ARDS) is one of the clinical manifestations in severe COVID-19 patients characterized by acute inflammation resulting in respiratory failure and death. Camellia sinensis L. or green tea extract has many beneficial secondary metabolites including polyphenols which have anti-inflammatory and anti-viral roles. This study was aimed to investigate the activity of green tea extract (GTE) as an anti-inflammatory on ARDS model cells. In this study, rat lung alveolar type II epithelial cells line (L2) was induced by lipopolysaccharide (LPS) to mimic the inflammation process in ARDS. These cells were then treated with GTE to determine the GTE effectiveness in reducing the inflammation. The GTE polyphenol constitutions were first confirmed using Liquid Chromatography with Tandem Mass Spectrometry (LC-MS/MS). The cytotoxic assay was conducted using MTS assay kit to determine the safe range of GTE concentrations that used in the next assay. The effectiveness of the GTE was determined by measuring pro-inflammatory cytokines (IL-1ß and IL-6) and inflammation-mediated enzymes (COX-2), both of which were by ELISA method. Furthermore, this study measured the ACE-2 and TMPRSS-2 gene expressions by qRT-PCR method. The results showed that GTE treatment significantly reduced pro-inflammatory cytokines IL-1ß, IL-6, inflammation-mediated enzyme COX-2, and significantly increased ACE-2 and TMPRSS-2 mRNA expressions. In short, green tea extract possesses the potential to alleviate inflammation. HIGHLIGHTS Acute Respiratory Distress Syndrome (ARDS) is one of clinical manifestations in severe COVID-19 patients characterized by acute inflammation results in respiratory failure and death In lung inflammation, the Angiotensin Converting Enzyme-2 (ACE-2) and Trans-Membrane Protease Serine-2 (TMPRSS-2) genes were lowly expressed, then causes alveolar tissue collapse High levels of inflammatory mediator cytokines would be secreted in respiratory tracts, such as Interleukin (IL)-1β, IL-6, and Cyclooxygenases (COX)-2 Polyphenols in green tea (Camelia sinensis L.) have been reported to have anti-inflammatory activities GRAPHICAL ABSTRACT

Transient Receptor Potential Ankyrin 1 (TRPA1) mediates IL-1β-Induced Thermoregulation

Abstract TRPA1 is a non-specific cation channel, that has been previously implicated in temperature regulation and inflammation. Administration of TRPA1 agonists induce significant changes in body temperature. Similarly, IL-1β, a cytokine mediator of inflammation and injury, induces a significant change in body temperature. Here we reasoned that TRPA1 plays a role in IL-1β mediated temperature regulation. To monitor body temperature in conscious and unrestrained mice, telemetry probes were implanted into the peritoneal cavity. Using chemogenetic technology, we generated a novel TRPA1-GqDREADD strain, in which TRPA1+ cells are activated by the administration of clozapine-N-oxide (CNO). Administration of CNO (ip) induces a significant change in body temperature (vehicle vs. CNO; 674.3 ± 29.3 AUC vs. 1646 ± 172 AUC; Welch’s T-test; p<.001). To determine if TRPA1 is responsible for IL-1β induced thermoregulation, wild type mice and TRPA1 KO mice were injected with IL-1β (5.0μg/kg, ip). As expected, wildtype mice had a significant change in body temperature. However, this response was significantly impaired in TRPA1 KO mice (wild type vs. TRPA1 KO; 1045 ± 35.29 AUC vs. 577.9 ± 26.13 AUC; Welch’s T-test; p<0.0001). To investigate whether selective TRPA1 expression in neurons is required for IL-1β-induced thermoregulation, we generated Syn-Cre/TRPA1fl/fl mice selectively devoid of TRPA1 expression in neurons. Selective ablation of TRPA1-expression in neurons significantly attenuates IL-1β-induced changes in body temperature (wild type vs. Syn-Cre/TRPA1fl/fl; 1082 ± 61.49 AUC vs. 775.8 ± 66.89 AUC Welch’s T-test; p<0.01). Together, these studies indicate that IL-1β-induced thermoregulation is mediated via neuronal TRPA1. Supported by grant from NIH to KJT and SSC

IL‐1β‐Induced Thermoregulation and Vagus Nerve Activity is Mediated by Transient Receptor Potential Ankyrin 1

Intraperitoneal administration of interleukin-1β (IL-1β), a cytokine mediator of inflammation and injury, induces afferent vagus nerve signaling and brain-mediated sickness syndrome. However, the mechanism of IL-1β signaling through the vagus nerve is unknown. Here we show that transient receptor potential ankyrin 1 (TRPA1) expression in sensory vagus neurons is required to mediateIL-1β-induced thermoregulation and vagus nerve activation. We monitored body temperature in conscious and unrestrained mice by radiotelemetry using probes implanted into peritoneal cavity. Intraperitoneal administration of IL-1β induced a significant change in body temperature in wild type mice. However, this response was significantly impaired in TRPA1 knock out mice (TRPA1 KO) (wild type vs. TRPA1 KO; 1045 ± 35.29 AUC vs. 577.9 ± 26.13 AUC; t-test with Welch's correction; p<0.0001). To investigate whether selective TRPA1 expression in neurons is required for IL-1β-induced thermoregulation, we generated Syn-Cre/TRPA1fl/fl mice selectively devoid of TRPA1 expression in neurons. Selective ablation of TRPA1-expression in neurons significantly attenuates IL-1β-induced changes in body temperature (wild type vs. Syn-Cre/TRPA1fl/fl; 1082 ± 61.49 AUC vs. 775.8 ± 66.89 AUC; t-test with Welch's correction; p<0.01). We have previously shown IL-1β induces sensory signaling by recording vagus nerve activity. Accordingly, here we collected extra-neural recordings from the cervical vagus nerve and as expected observed administration of IL-1β induced a significant increase in vagus nerve activity (total spikes 5 minutes pre- and post-administration: 85.6 ± 0.17 spikes vs. 9998.0 ± 3617.0 spikes; t-test; p<0.01). Moreover, no significant changes in vagus nerve activity occurred in TRPA1 KO mice (pre vs post-administration: 867.3 ± 395.7 spikes vs. 1069.0 ± 455.8 spikes, t-test, N.S.), and in Syn-Cre/TRPA1fl/fl mice (pre vs post-administration: 2179.0 ± 558.8 spikes vs. 1996.0 ± 460.8 spikes; t-test; N.S.). Whole-cell patch-clamp recordings and calcium imaging revealed TRPA1 is required to mediate IL-1β-dependent activation of vagus sensory neurons. Together, these studies indicate IL-1β-induced thermoregulation and vagus nerve activation is mediated by TRPA1.

Design, synthesis and anti-inflammatory activity of imidazol-5-yl pyridine derivatives as p38α/MAPK14 inhibitor

P38α/MAPK14 is intracellular signalling regulator involved in biosynthesis of inflammatory mediator cytokines (TNF-α, IL-1, IL-6, and IL-1b), which induce the production of inflammatory proteins (iNOS, NF-kB, and COX-2). In this study, drug repurposing strategies were followed to repositioning of a series of B-RAF V600E imidazol-5-yl pyridine inhibitors to inhibit P38α kinase. A group 25 reported P38α kinase inhibitors were used to build a pharmacophore model for mapping the target compounds and proving their affinity for binding in P38α active site. Target compounds were evaluated for their potency against P38α kinase, compounds 11a and 11d were the most potent inhibitors (IC50 = 47 nM and 45 nM, respectively).In addition, compound 11d effectively inhibited the production of proinflammatory cytokinesTNF-α, 1L-6, and 1L-1β in LPS-induced RAW 264.7 macrophages with IC50 values of 78.03 nM, 17.6 µM and 82.15 nM, respectively.The target compounds were tested for their anti-inflammatory activity by detecting the reduction of Nitric oxide (NO) and prostaglandin (PGE2) production in LPS-stimulated RAW 264.7 macrophages. Compound 11d exhibited satisfied inhibitory activity of the production of PGE2 and NO with IC50 values of 0.29 µM and 0.61 µM, respectively. Molecular dynamics simulations of the most potent inhibitor 11d were carried out to illustrate its conformational stability in the binding site of P38α kinase.

Characterization and Modulation of Systemic Inflammatory Response to Exhaustive Exercise in Relation to Oxidative Stress.

Exhaustive exercise induces systemic inflammatory responses, which are associated with exercise-induced tissue/organ damage, but the sources and triggers are not fully understood. Herein, the basics of inflammatory mediator cytokines and research findings on the effects of exercise on systemic inflammation are introduced. Subsequently, the association between inflammatory responses and tissue damage is examined in exercised and overloaded skeletal muscle and other internal organs. Furthermore, an overview of the interactions between oxidative stress and inflammatory mediator cytokines is provided. Particularly, the transcriptional regulation of redox signaling and pro-inflammatory cytokines is described, as the activation of the master regulatory factor nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is involved directly or indirectly in controlling pro-inflammatory genes and antioxidant enzymes expression, whilst nuclear factor-kappa B (NF-κB) regulates the pro-inflammatory gene expression. Additionally, preventive countermeasures against the pathogenesis along with the possibility of interventions such as direct and indirect antioxidants and anti-inflammatory agents are described. The aim of this review is to give an overview of studies on the systematic inflammatory responses to exercise, including our own group as well as others. Moreover, the challenges and future directions in understanding the role of exercise and functional foods in relation to inflammation and oxidative stress are discussed.

Isolation and characterization of phage (ETP-1) specific to multidrug resistant pathogenic Edwardsiella tarda and its in vivo biocontrol efficacy in zebrafish (Danio rerio)

Edwardsiella tarda phage (ETP-1) was isolated from marine fish farm water to characterize its effect against pathogenic multidrug-resistant E. tarda. According to transmission electron microscopy results, ETP-1 is classified as a member of the family Podoviridae. ETP-1 showed MOI dependent E. tarda growth inhibition, a latent period of 60 min, and burst size of 100 PFU per infected cells. In host range tests, five out of eight E. tarda strains were sensitive to ETP-1 which had efficiency of plating index in the range 1–1.28. ETP-1 was stable over a broad range of pH and temperature. The size of the ETP-1 genome was predicted to be approximately 40 kb. Zebrafish exposed to ETP-1 showed no adverse gene responses to the inflammatory mediator cytokines, il1-β, tnf-α, il-6, and il-10, the chemokine, cxcl-8a, and reactive oxygen species, sod-1. When zebrafish were bath exposed to ETP-1 for 12 days and simultaneously challenged with E. tarda (1.08 × 105 CFU fish−1), the survival rate was higher in phage exposed fish (68%) compared to that of the control (18%) until 4 days post challenge. Our results suggest that ETP-1 can be used as a potential bio-therapeutic candidate to control multi-drug resistant E. tarda infection in aquaculture.

High mobility group box‐1 increases epithelial sodium channel activity and inflammation in small airway epithelial cells

In Cystic Fibrosis (CF) patients, inherited defects in anion transport leads to hyperactive epithelial Na+ channel (ENaC) activity. ENaC dysfunction in CF lung is known to cause airway surface liquid dehydration. Thick and dry mucus, in turn, leads to an inflammatory lung phenotype that often occurs without detection of infection in CF patients. Many investigative groups have reported that airway tissue and fluid from murine models exhibiting the CF lung phenotype (Scnn1b‐Tr mice), as well as CF patients, have increased levels of high mobility group box‐1 (HMGB‐1). HMGB‐1 is a cytokine mediator of inflammation and is a biomarker for severity of CF lung disorder. Herein, we hypothesize that HMGB‐1 plays an important role in the pathogenic regulation of ENaC, inflammation, and fibrosis in sterile airways. To begin testing this hypothesis, we measured transepithelial sodium current (Isc) and single channel ENaC open probability (Po) in human small airway epithelial cells (SAEC) in the presence or absence of 1 mg/mL human HMGB‐1 peptide. Electrophysiological measurements show that HMGB‐1 significantly increased amiloride‐sensitive ENaC Isc from −9.7±1.4 μA/cm2 to −18.4±2.9 μA/cm2 in confluent monolayers of SAEC (n=12; p=0.01) within 30 min. Subsequent amiloride treatment of the same SEAC monolayers decreased Isc 71%. Single channel measurements were conducted in primary SAEC obtained from 4 separate donor lungs in the cell‐attached configuration; HMGB‐1 increased ENaC Po from 0.18±0.02 to 0.35±0.04 (n=17; p&lt;0.01) in single channel analysis. Mean absolute total cell counts were significantly higher in bronchoalveolar lavage fluid (BALF) from mice intraperitoneally (IP) injected with HMBG‐1 (10 mg in 1 mL saline/kg) vs vehicle injected mice. Total immune cell counts were 27.4×103± 8.8×103 (in HMGB‐1) vs. 5.2×103±1.3X103 (in vehicle) injected mice (n=8 counts from 2 independent studies; p&lt;0.05). Masson's Trichrome labeling of IP injected mice show that HMGB‐1 significantly increases pulmonary fibrosis (see Fig 1). Flow cytometric analysis of HMGB‐1 and vehicle injected mice showed significant increase in IL‐1β, IL‐10, IL‐6, IL‐27, IL‐17A, IFN‐β, and GM‐CSF (n=3; p&lt;0.05; see Fig 2). Together, our data suggests that HMGB‐1 plays an important role in the CF lung phenotype; additional studies are underway to strengthen these observations. Impact: Successful completion of our work can lead to novel therapies needed to counteract ENaC dysfunction and inflammation in the CF lung.Support or Funding InformationThis work was supported by NIH 1 R01 HL137033‐01A1 awarded to MH.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Cytokine Response to Exercise and Its Modulation

Strenuous exercise induces such inflammatory responses as leukocytosis (neutrophilia) and symptoms as delayed-onset muscle soreness and swelling. However, the association between inflammatory mediator cytokines and oxidative stress is not fully delineated. Herein, in addition to basic background information on cytokines, research findings on exertional effects on cytokine release and the underlying mechanisms and triggers are introduced. Then, the associations among cytokine responses, oxidative stress, and tissue damage are described not only in overloaded skeletal muscle, but also in other internal organs. Furthermore, we introduce preventive countermeasures against the exhaustive exercise-induced pathogenesis together with the possibility of antioxidant interventions.

Vascular Endothelial Growth Factor: A New Paradigm for Targeting Various Diseases

Vascular endothelial growth factor is a signaling protein, which is responsible for the angiogenesis process. Variation in its expression leads to various disorders like cancer, diabetes, psoriasis and neuronal imbalance (depression) etc. The abundance of VEGF (VEGF-A, B, C) concentration is present in the kidney, heart, lung, ovary, thyroid gland, neurons, embryonic tissue etc. The regulation of VEGF expression is controlled by the hypoxia condition, hormonal regulation, inflammatory mediator cytokines and growth hormone. The VEGF binds to the VEGFR1, and VEGFR2 tyrosine kinase receptors causing conformational changes resulting in the endothelial cell proliferation, increased vascular permeability, and formation of new blood vessel. The high level of VEGF- A activity found in the synovial fluid leads to rheumatoid arthritis, whereas in the retinal cell it results in diabetic retinopathy. The tumor growth factor induced VEGF A expression in keratin cell lead to psoriasis. The higher level of VEGF activity increased neovascularization which is beneficial in cerebral ischemia, as well as in the growth of the neurons. VEGF is also considered to be an important factor in tumor invasion and metastasis. Various growth factors stimulate or participated in tumor angiogenesis. Therefore, the Anti-VEGF therapy can be a potential option for treatment of psoriasis, rheumatoid arthritis, diabetic retinopathy, and cancer. The (VEGF) gene expression modulation will lead to the new therapeutic possibilities in the future. Keywords: Angiogenesis, diabetes mellitus, psoriasis, rheumatoid arthritis, vascular endothelial growth factor.

Role of HMGB1 in regulation of STAT3 expression in CD4+ T cells from patients with aGVHD after allogeneic hematopoietic stem cell transplantation

Treg/Th17 balance plays a critical role in maintaining immune homeostasis of acute graft-versus-host disease (aGVHD) patients. STAT3 is an important factor involved in the instability of Treg and the promotion of Th17. HMGB1 is a cytokine mediator of inflammation and an important chromatin protein regulating gene transcription. In this study, we found that the expressions of HMGB1 and STAT3 were higher in CD4+ T cells of patients with aGVHD compared with those without aGVHD, and the HMGB1 expression was positively correlated with the STAT3 expression. Simultaneously, their expressions were positively correlated with the severity of the aGVHD. We also demonstrated that HMGB1 could regulate the expression of STAT3 by modulation of its DNA methylation in CD4+ T cells, moreover downregulated HMGB1 in aGVHD CD4+ T cells could change the ratio of Treg/Th17. These data strongly suggest that HMGB1 plays a crucial role in the regulation of Treg/Th17 and progression of aGVHD.

Removal of HMGB1 in inflammatory bowel disease using DNA-beads. (P5197)

Abstract Inflammatory bowel disease (IBD) affects millions of Americans, and costs 1.7 billion annually. High mobility group box 1 (HMGB1) is a cytokine mediator of inflammation in the pathogenesis of IBD. Elevated levels of HMGB1 have been observed in human IBD and in mouse models of colitis (Vitali R, et al. Am J Gastroenterol. 2011. Yamasaki H, et al. Mol Med Report. 2009). Blocking HMGB1 induction by either anti-HMGB1 antibody or ethyl pyruvate (HMGB1 inhibitor) was able to ameliorate the inflammation in colitis mice. DNA with certain sequences or structures has been shown with high affinity binding to HMGB1, and has been reported to attenuate inflammatory responses by blocking HMGB1. In this study, we conjugated DNA sequences to sepharose beads and utilized them as novel reagents to remove HMGB1. We found that the DNA-beads were able to bind HMGB1 with a capacity of 7.6 μmol/L, and each immobilized DNA molecule was able to bind three HMGB1 molecules (DNA:HMGB1 ratio = 1:3). DNA-beads were able to capture HMGB1 from RAW 264.7 cell supernatant stimulated with LPS and from sera of septic mice induced by cecal ligation and puncture. When applied to stools of mice with dextran sulfate sodium (DSS) induced colitis, DNA-beads were able to capture HMGB1 from stools of these colitis mice. Hence, our data suggest a therapeutic potential for DNA-beads to remove HMGB1 in inflammatory diseases such as IBD.

ShRNAs targeting high-mobility group box-1 inhibit E-selectin expression via homeobox A9 in human umbilical vein endothelial cells

The nucleus of the endothelial cell contains large amounts of high-mobility group box protein 1 (HMGB1), a cytokine mediator of inflammation, and the endothelium may be a crucial source of HMGB1 during the inflammatory response. Therefore, the downregulation of HMGB1 expression by RNA interference (RNAi) may decrease inflammatory activity. The aim of this study was to investigate the possible mechanism of action and the effect of HMGB1 on homeobox A9 (HOXA9) and E-selectin expression. Recombinant human full-length HMGB1 was cloned by PCR amplification from human umbilical vein endothelial cells (HUVECs) and then subcloned into a pcDNA‑3.1-myc-his-B vector. Specific short hairpin RNAs (shRNAs) for the HMGB1 target sequence and a scrambled sequence were designed, synthesized and cloned into a pRNA‑U6.1/Neo vector. Specific small interfering RNAs (siRNAs) for the HOXA9 target sequence were commercially prepared and the expression levels of HMGB1, HOXA9, intracellular adhesion molecule 1 (ICAM1), vascular cell adhesion molecule 1 (VCAM1) and E-selectin were detected using real-time PCR and western blot analysis. The expression of the full-length HMGB1 gene and protein was verified in HUVECs. The shRNA for HMGB1 and siRNA for HOXA9 successfully decreased the expression levels of HMGB1 and HOXA9, respectively. ICAM1, VCAM1 and E-selectin were downregulated through HMGB1 interference in HUVECs, and HMGB1 shRNA decreased E-selectin expression by HOXA9. These results demonstrated the potential use of specific siRNA targeting HMGB1 expression for the development of novel therapeutic agents for inflammatory disorders.

Attenuation of lipopolysaccharide (LPS)-induced cytotoxicity by tocopherols and tocotrienols

Lipopolysaccharide (LPS) induces host inflammatory responses and tissue injury and has been implicated in the pathogenesis of various age-related diseases such as acute respiratory distress syndrome, vascular diseases, and periodontal disease. Antioxidants, particularly vitamin E, have been shown to suppress oxidative stress induced by LPS, but the previous studies with different vitamin E isoforms gave inconsistent results. In the present study, the protective effects of α- and γ-tocopherols and α- and γ-tocotrienols on the oxidative stress induced by LPS against human lung carcinoma A549 cells were studied. They suppressed intracellular reactive oxygen formation, lipid peroxidation, induction of inflammatory mediator cytokines, and cell death. Tocopherols were incorporated into cultured cells much slower than tocotrienols but could suppress LPS-induced oxidative stress at much lower intracellular concentration than tocotrienols. Considering the bioavailability, it was concluded that α-tocopherol may exhibit the highest protective capacity among the vitamin E isoforms against LPS-induced oxidative stress.

The Amine-Containing Cutaneous Irritant Heptylamine Inhibits the Volume-Regulated Anion Channel and Mobilizes Intracellular Calcium in Normal Human Epidermal Keratinocytes

Many amines are skin irritants and cause contact dermatitis. However, little is known about their mechanisms of action in keratinocytes except that they induce the release of the inflammatory mediators cytokines and ATP. Here, we tested whether volume-regulated anion channels (VRACs) in primary cultures of normal human epidermal keratinocytes are modulated by the referenced amine-containing cutaneous irritant heptylamine. Under isotonic conditions, we isolated the VRAC current (I(VRAC)) from other conductances using a high Ca(2+)-buffering internal solution. I(VRAC) ran up after patch rupturing and reached a plateau within 15 min. It was reversibly and dose-dependently inhibited by heptylamine with an IC(50) value of 260 microM. Cell-swelling caused by the application of a hypotonic solution increased 2.7-fold I(VRAC) and reduced the inhibition of VRAC by heptylamine with a dose-response curve shifted approximately 10-fold to the right. In addition, we showed, using cell-attached patch recordings, that adding heptylamine to the bath inhibited VRAC activity. This suggests that heptylamine diffuses into the membrane to inhibit VRAC. Finally, we demonstrated that heptylamine induced Ca(2+)-store depletion and that VRAC inhibition was not caused by the increase in cytosolic Ca(2+). Taken together, these results identify heptylamine as a blocker of VRAC and suggest that Ca(2+)-store depletion may be involved in mechanisms of irritant contact dermatitis caused by heptylamine.

An evolving story of lipoprotein-associated phospholipase A2 in atherosclerosis and cardiovascular risk prediction

This editorial refers to ‘Association of lipoprotein-associated phospholipase A2 levels with coronary artery disease risk factors, angiographic coronary artery disease, and major adverse events at follow-up’† by E.S. Brilakis et al. , on page 137 Over the past 50 years, the age-adjusted mortality rate from cardiovascular disease has decreased substantially. Despite the improved mortality rate, there is evidence that actual cardiovascular event rates remain relatively unchanged (i.e. more people are surviving acute events), and heart disease and stroke continue to be leading causes of death in Western societies.1 Intensive research efforts are currently under way with the goal of further reducing the global burden of cardiovascular disease. An improved understanding of vascular biology and the pathogenesis of atherosclerosis—including the role of inflammatory processes—may prove helpful in achieving this goal. Atherosclerosis is a condition involving numerous complex processes within the vessel wall that can be characterized as an inflammatory response to injury. The ‘injury’ is most likely attributable to oxidized low-density lipoprotein (LDL) cholesterol, and the inflammatory response is mediated predominantly by monocyte-derived macrophages and T-lymphocytes.2 Together, these cells, along with endothelial cells and vascular smooth muscle cells, express or enhance the expression of inflammatory mediators—cytokines, chemokines, adhesion molecules, growth factors, and other bioactive substances—that play an important role in each stage of atherosclerosis, from initial plaque formation to plaque (in)stability/rupture. Improvements in the understanding of vascular biology have led investigators to evaluate whether certain components of the inflammatory processes may be helpful in identifying high-risk individuals with … *Corresponding author. Tel.: +1 610 270-7227; fax: +1 610 270-6206 E-mail address : colin.h.macphee{at}gsk.com

α-MSH peptides inhibit acute inflammation induced in mice by rIL-1β, rIL-6, rTNF-α and endogenous pyrogen but not that caused by LTB 4, PAF and rIL-8

The neuropeptide α-melanocyte stimulating hormone [α-MSH(1–13)] occurs in the pituitary, brain, skin and other tissues and receptors for this molecule are likewise widespread. In previous research, this tridecapeptide, which shares its amino acid sequence with ACTH(1–13), was shown to have both potent antipyretic activity and a role in the endogenous control of the febrile response. α-MSH(1–13) and its COOH-terminal tripeptide were subsequently found to inhibit inflammation induced by general stimuli such as topical application of an irritant. The aim in the present experiments was to determine if these peptides can inhibit acute inflammatory responses induced in mice by injection of individual cytokines, endogenous pyrogen (EP), a natural cytokine mixture, and other mediators of inflammation. Inflammation induced in the mouse ear by rIL-1β, rIL-6 or rTNF-α was inhibited by α-MSH and a d-valine-substituted analog of α-MSH(11–13) whereas substantial doses of α-MSH(1–13) did not alter inflammation induced by LTB 4, PAF and IL-8. Both peptides inhibited edema caused in the mouse paw by local injection of EP. The results indicate that α-MSH molecules antagonize the actions of certain cytokine mediators of inflammation, consistent with previous observations of anti-cytokine activity of these peptides. Failure to inhibit edema caused by LTB 4, PAF and IL-8 suggests that, in inflammation induced by general stimuli, such as EP, the peptides act prior to the release of these mediators of the inflammatory response. Because of the anticytokine/anti-inflammatory actions of the α-MSH molecules they may be useful in understanding the cytokine network and for treatment of inflammatory diseases.

Platelet derived growth factor and central nervous system regeneration: [formula omitted]. Dept. of Neurobiol. Weizmann Inst. of Science, Rehovot, Israel

The neuropeptide α-melanocyte stimulating hormone [α-MSH(1–13)] occurs in the pituitary, brain, skin and other tissues and receptors for this molecule are likewise widespread. In previous research, this tridecapeptide, which shares its amino acid sequence with ACTH(1–13), was shown to have both potent antipyretic activity and a role in the endogenous control of the febrile response. α-MSH(1–13) and its COOH-terminal tripeptide were subsequently found to inhibit inflammation induced by general stimuli such as topical application of an irritant. The aim in the present experiments was to determine if these peptides can inhibit acute inflammatory responses induced in mice by injection of individual cytokines, endogenous pyrogen (EP), a natural cytokine mixture, and other mediators of inflammation. Inflammation induced in the mouse ear by rIL-1β, rIL-6 or rTNF-α was inhibited by α-MSH and a d-valine-substituted analog of α-MSH(11–13) whereas substantial doses of α-MSH(1–13) did not alter inflammation induced by LTB4, PAF and IL-8. Both peptides inhibited edema caused in the mouse paw by local injection of EP. The results indicate that α-MSH molecules antagonize the actions of certain cytokine mediators of inflammation, consistent with previous observations of anti-cytokine activity of these peptides. Failure to inhibit edema caused by LTB4, PAF and IL-8 suggests that, in inflammation induced by general stimuli, such as EP, the peptides act prior to the release of these mediators of the inflammatory response. Because of the anticytokine/anti-inflammatory actions of the α-MSH molecules they may be useful in understanding the cytokine network and for treatment of inflammatory diseases.