TNF-α Receptor Expression Research Articles

Resveratrol-decreased hyperalgesia mediated by the P2X7 receptor in gp120-treated rats.

BackgroundChronic pain is a common symptom in human immunodeficiency virus (HIV)-1 infection/acquired immunodeficiency syndrome patients. The literature shows that the HIV envelope glycoprotein 120 (gp120) can directly cause hyperalgesia by stimulating primary sensory afferent nerves. The P2X7 receptor in the dorsal root ganglia (DRG) is closely related to neuropathic and inflammatory pain. In this study, we aimed to explore the effect of resveratrol (RES) on gp120-induced neuropathic pain that is mediated by the P2X7 receptor in the rat DRG.ResultsMechanical hyperalgesia in rats treated with gp120 was increased compared with that in the sham group. The P2X7 expression levels in rats treated with gp120 were higher than those in the sham group. Co-localization of the P2X7 receptor and glial fibrillary acidic protein (GFAP, a marker of satellite glial cells [SGCs]) in the DRG SGCs of the gp120 group exhibited more intense staining than that of the sham group. RES decreased the mechanical hyperalgesia and P2X7 expression levels in gp120 treatment rats. Co-localization of the P2X7 receptor and GFAP in the gp120+ RES group was significantly decreased compared to the gp120 group. RES decreased the IL-1β and TNF-α receptor (R) expression levels and ERK1/2 phosphorylation levels as well as increased IL-10 expression in the DRG of gp120-treated rats. Whole cell clamping demonstrated that RES significantly inhibited adenosine triphosphate-activated currents in HEK293 cells that were transfected with the P2X7 plasmid.ConclusionsRES relieved mechanical hyperalgesia in gp120-treated rats by inhibiting the P2X7 receptor.

Apolipoprotein CIII Overexpression-Induced Hypertriglyceridemia Increases Nonalcoholic Fatty Liver Disease in Association with Inflammation and Cell Death.

Nonalcoholic fatty liver disease (NAFLD) is the principal manifestation of liver disease in obesity and metabolic syndrome. By comparing hypertriglyceridemic transgenic mice expressing apolipoprotein (apo) CIII with control nontransgenic (NTg) littermates, we demonstrated that overexpression of apoCIII, independent of a high-fat diet (HFD), produces NAFLD-like features, including increased liver lipid content; decreased antioxidant power; increased expression of TNFα, TNFα receptor, cleaved caspase-1, and interleukin-1β; decreased expression of adiponectin receptor-2; and increased cell death. This phenotype is aggravated and additional NAFLD features are differentially induced in apoCIII mice fed a HFD. HFD induced glucose intolerance together with increased gluconeogenesis, indicating hepatic insulin resistance. Additionally, the HFD led to marked increases in plasma TNFα (8-fold) and IL-6 (60%) in apoCIII mice. Cell death signaling (Bax/Bcl2), effector (caspase-3), and apoptosis were augmented in apoCIII mice regardless of whether a HFD or a low-fat diet was provided. Fenofibrate treatment reversed several of the effects associated with diet and apoCIII expression but did not normalize inflammatory traits even when liver lipid content was fully corrected. These results indicate that apoCIII and/or hypertriglyceridemia plays a major role in liver inflammation and cell death, which in turn increases susceptibility to and the severity of diet-induced NAFLD.

Analgesic Effect of Photobiomodulation on Bothrops Moojeni Venom-Induced Hyperalgesia: A Mechanism Dependent on Neuronal Inhibition, Cytokines and Kinin Receptors Modulation.

BackgroundEnvenoming induced by Bothrops snakebites is characterized by drastic local tissue damage that involves an intense inflammatory reaction and local hyperalgesia which are not neutralized by conventional antivenom treatment. Herein, the effectiveness of photobiomodulation to reduce inflammatory hyperalgesia induced by Bothrops moojeni venom (Bmv), as well as the mechanisms involved was investigated.Methodology/Principal FindingsBmv (1 μg) was injected through the intraplantar route in the right hind paw of mice. Mechanical hyperalgesia and allodynia were evaluated by von Frey filaments at different time points after venom injection. Low level laser therapy (LLLT) was applied at the site of Bmv injection at wavelength of red 685 nm with energy density of 2.2 J/cm2 at 30 min and 3 h after venom inoculation. Neuronal activation in the dorsal horn spinal cord was determined by immunohistochemistry of Fos protein and the mRNA expression of IL-6, TNF-α, IL-10, B1 and B2 kinin receptors were evaluated by Real time-PCR 6 h after venom injection. Photobiomodulation reversed Bmv-induced mechanical hyperalgesia and allodynia and decreased Fos expression, induced by Bmv as well as the mRNA levels of IL-6, TNF-α and B1 and B2 kinin receptors. Finally, an increase on IL-10, was observed following LLLT.Conclusion/SignificanceThese data demonstrate that LLLT interferes with mechanisms involved in nociception and hyperalgesia and modulates Bmv-induced nociceptive signal. The use of photobiomodulation in reducing local pain induced by Bothropic venoms should be considered as a novel therapeutic tool for the treatment of local symptoms induced after bothropic snakebites.

Contribution of Pro-inflammatory Cytokine Signaling within Midbrain Periaqueductal Gray to Pain Sensitivity in Parkinson's Disease via GABAergic Pathway.

Hypersensitive pain response is often observed in patients with Parkinson's disease (PD); however, the mechanisms responsible for hyperalgesia are not well understood. Chronic neuroinflammation is one of the hallmarks of PD pathophysiology. Since the midbrain periaqueductal gray (PAG) is an important component of the descending inhibitory pathway controlling on central pain transmission, we examined the role for pro-inflammatory cytokines (PICs) system of PAG in regulating exaggerated pain evoked by PD. We used a rat model of PD to perform the experimental protocols. PD was induced by microinjection of 6-hydroxydopamine to lesion the left medial forebrain bundle. Pain responses to mechanical and thermal stimulation were first examined in control rats and PD rats. Then, ELISA and Western Blot analysis were used to determine PIC levels and their receptors expression. Protein expression of IL-1β, IL-6, and TNF-α receptors (namely, IL-1R, IL-6R, and TNFR subtype TNFR1) in the plasma membrane PAG of PD rats was upregulated, whereas the total expression of PIC receptors was not significantly altered. The ratio of membrane protein and total protein (IL-1R, IL-6R, and TNFR1) was 1.48 ± 0.15, 1.59 ± 0.18, and 1.67 ± 0.16 in PAG of PD rats (P < 0.05 vs. their respective controls). This was accompanied with increases of PICs of PAG and decreases of GABA (623 ± 21 ng/mg in control rats and 418 ± 18 ng/mg in PD rats; P < 0.05 vs. control rats) and withdrawal thresholds to mechanical and thermal stimuli. Our data further showed that the concentrations of GABA and withdrawal thresholds were largely restored by blocking those PIC receptors in PAG of PD rats. Stimulation of GABA receptors in PAG of PD rats also blunted a decrease in withdrawal thresholds. Our data suggest that upregulation of the membrane PIC receptor in the PAG of PD rats is likely to impair the descending inhibitory pathways in regulating pain transmission and thereby plays a role in the development of hypersensitive pain response in PD.

Coordinated expression of TNFα- and VEGF-mediated signaling components by placental macrophages in early and late pregnancy

IntroductionMononuclear phagocytes are thought to significantly contribute to cytokine regulation at the maternal-foetal interface, but the role of placental macrophages has been poorly investigated. TNFα and VEGF were demonstrated to have regulatory effects on basic structures of the placenta, particularly the trophoblast and blood vessels. The aims of this study were to determine the expression of TNFα, VEGF and related receptors in placental macrophages, and how does the participation of placental macrophages alter with gestational age in TNFα- and VEGF-mediated signaling. MethodsMacrophages were isolated from placental villous tissue from normal pregnancies at either 9–12 or 38–40 weeks gestation. Cell surface receptors (TNFR1, TNFR2, VEGFR1, and VEGFR2) and intracellular TNFα and VEGF were quantified by flow cytometry after antibody staining. Basal and stimulated secretion of both cytokines and soluble TNF receptors was quantified by cytometric bead arrays. Secreted VEGFR1 was measured by ELISA. ResultsThe expression of TNFR1 and VEGFR1 was remarkably variable and did not change from first to third trimester. There was minimal basal TNFα production in the placental macrophages, but nearly all cells in the population produced VEGF. TNFα and VEGF secretion increased with gestational age accompanied by decreased secretion of the antagonists sTNFR1 and sVEGFR. Macrophages isolated from early term placentas were less effective in responding to bacterial endotoxin. Lipopolysaccharide induced increases in the secretion of TNFα, TNFR1, TNFR2, and VEGFR1 but did not affect the production of VEGF. In late pregnancy, a significant correlation was observed between TNFR1 and VEGFR1. DiscussionThe progression of pregnancy is accompanied by the concerted increase in TNFα and VEGF secretion and decrease in the production of their soluble receptors, but the expression of cell surface receptors does not depend on gestational age. The observed patterns of basal and stimulated expression of TNFα and VEGF may reflect the dual immune and morphogenetic roles of placental macrophages in gestation. Compatible patterns of TNFR1 and VEGFR1 expression suggest common regulatory pathways for these receptors.

Anti-TNFα agents curb platelet activation in patients with rheumatoid arthritis

BackgroundCardiovascular disease is important in rheumatoid arthritis (RA). Tissue factor (TF) is expressed upon platelet activation and initiates coagulation. Anti-tumour necrosis factor-α (TNFα) agents seem to decrease RA-associated cardiovascular events....

Editorial: Post-Exercise Recovery: Fundamental and Interventional Physiology.

Editorial: Post-Exercise Recovery: Fundamental and Interventional Physiology.

TNFα Augments Cytokine-Induced NK Cell IFNγ Production through TNFR2

NK cells play a central role in innate immunity, acting directly through cell-mediated cytotoxicity and by secreting cytokines. TNFα activation of TNFR2 enhances NK cell cytotoxicity, but its effects on the other essential function of NK cells - cytokine production, for which IFNγ is paramount - are poorly defined. We identify the expression of both TNFα receptors on human peripheral blood NK cells (TNFR2 > TNFR1) and show that TNFα significantly augments IFNγ production from IL-2-/IL-12-treated NK cells in vitro, an effect mimicked by a TNFR2 agonistic antibody. TNFα also enhanced murine NK cell IFNγ production via TNFR2 in vitro. In a mouse model characterized by the hepatic recruitment and activation of NK cells, TNFR2 also regulated NK cell IFNγ production in vivo. Specifically, in this model, after activation of an innate immune response, hepatic numbers of TNFR2-expressing and IFNγ-producing NK cells were both significantly increased; however, the frequency of IFNγ-producing hepatic NK cells was significantly reduced in TNFR2-deficient mice. We delineate an important role for TNFα, acting through TNFR2, in augmenting cytokine-induced NK cell IFNγ production in vivo and in vitro, an effect with significant potential implications for the regulation of innate and adaptive immune responses.

Lobaric Acid Inhibits VCAM-1 Expression in TNF-α-Stimulated Vascular Smooth Muscle Cells via Modulation of NF-κB and MAPK Signaling Pathways.

Lichens have been known to possess multiple biological activities, including anti-proliferative and anti-inflammatory activities. Vascular cell adhesion molecule-1 (VCAM-1) may play a role in the development of atherosclerosis. Hence, VCAM-1 is a possible therapeutic target in the treatment of the inflammatory disease. However, the effect of lobaric acid on VCAM-1 has not yet been investigated and characterized. For this study, we examined the effect of lobaric acid on the inhibition of VCAM-1 in tumor necrosis factor-alpha (TNF-α)-stimulated mouse vascular smooth muscle cells. Western blot and ELISA showed that the increased expression of VCAM-1 by TNF-α was significantly suppressed by the pre-treatment of lobaric acid (0.1–10 μg/ml) for 2 h. Lobaric acid abrogated TNF-α-induced NF-κB activity through preventing the degradation of IκB and phosphorylation of extracellular signal-regulated kinases (ERK), c-Jun N-terminal kinases (JNK), and p38 mitogen activated protein (MAP) kinase. Lobaric acid also inhibited the expression of TNF-α receptor 1 (TNF-R1). Overall, our results suggest that lobaric acid inhibited VCAM-1 expression through the inhibition of p38, ERK, JNK and NF-κB signaling pathways, and downregulation of TNF-R1 expression. Therefore, it is implicated that lobaric acid may suppress inflammation by altering the physiology of the atherosclerotic lesion.

Vasoactive intestinal peptide (VIP) differentially affects inflammatory immune responses in human monocytes infected with viable Salmonella or stimulated with LPS

We compared the effect of VIP on human blood monocytes infected with Salmonella typhimurium 4/74 or stimulated with LPS. VIP (10−7M) increased monocyte viability by 24% and 9% when cultured for 24h with 4/74 or Salmonella LPS (100ng/ml), respectively. Significantly increased (P<0.05) numbers of 4/74 were also recovered from monocytes co-cultured with VIP after 6h post-infection (pi) and this remained high after 24h pi. Both 4/74 and LPS increased (P<0.05) the concentration of TNF-α, IL-1β and IL-6 measured in monocyte supernatants. However, LPS induced this effect more rapidly while, with the exception of IL-6, 4/74 induced higher concentrations (P<0.05). VIP significantly decreased (P<0.05) TNF-α and IL-1β production by 4/74-infected monocytes after 6 pi, but only after 24h in LPS-cultured monocytes. This trend was reversed for IL-6 production. However, TNF-α and IL-1β production by 4/74-infected monocytes, cultured with VIP, still remained higher (P<0.05) than concentrations measured in supernatants cultured only with LPS. VIP also increased (P<0.05) production of anti-inflammatory IL-10 in both 4/74 and LPS cultures after 24h. We also show a differential effect of VIP on the expression of TNFα and IL-6 receptors, since VIP was only able to decreased expression in LPS-stimulated monocytes but not in 4/74-infected monocytes.In conclusion, we show a differential effect of VIP on human monocytes infected with virulent Salmonella or stimulated with LPS. Our study suggests that the use of VIP in bacteraemia and/or sepsis may be limited to an adjunctive therapy to antibiotic treatment.

Lipoic acid and pentoxifylline mitigate nandrolone decanoate-induced neurobehavioral perturbations in rats via re-balance of brain neurotransmitters, up-regulation of Nrf2/HO-1 pathway, and down-regulation of TNFR1 expression

Behavioral perturbations associated with nandrolone decanoate abuse by athletes and adolescents may be attributed to oxidative stress and inflammation. However, the underlying mechanisms are not yet fully explored. On the other hand, the natural antioxidant lipoic acid can pass the blood brain barrier and enhance Nrf2/HO-1 (nuclear factor erythroid-2 related factor 2/heme oxygenase-1) pathway. In addition, the phosphodiesterase-IV inhibitor xanthine derivative pentoxifylline has a remarkable inhibitory effect on tumor necrosis factor-alpha (TNF-α). Therefore, this study aimed at investigation of the possible protective effects of lipoic acid and/or pentoxifylline against nandrolone-induced neurobehavioral alterations in rats. Accordingly, male albino rats were randomly distributed into seven groups and treated with either vehicle, nandrolone (15mg/kg, every third day, s.c.), lipoic acid (100mg/kg/day, p.o.), pentoxifylline (200mg/kg/day, i.p.), or nandrolone with lipoic acid and/or pentoxifylline. Rats were challenged in the open field, rewarded T-maze, Morris water maze, and resident–intruder aggression behavioral tests. The present findings showed that nandrolone induced hyperlocomotion, anxiety, memory impairment, and aggression in rats. These behavioral abnormalities were accompanied by several biochemical changes, including altered levels of brain monoamines, GABA, and acetylcholine, enhanced levels of malondialdehyde and TNF-α, elevated activity of acetylcholinesterase, and up-regulated expression of TNF-α receptor-1 (TNFR1). In addition, inhibited catalase activity, down-regulated Nrf2/HO-1 pathway, and suppressed acetylcholine receptor expression were observed. Lipoic acid and pentoxifylline combination significantly mitigated all the previously mentioned deleterious effects mainly via up-regulation of Nrf2/HO-1 pathway, inhibition of TNF-α and down-regulation of TNFR1 expression. In conclusion, the biochemical and histopathological findings of this study revealed the protective mechanisms of lipoic acid and pentoxifylline against nandrolone-induced behavioral changes and neurotoxicity in rats.

TNF-α and TNFR1 responses to recovery therapies following acute resistance exercise.

The purpose of this investigation was to compare the effect of two commonly used therapeutic modalities (a) neuromuscular electrical stimulation (NMES) and (b) cold water immersion (CWI) on circulating tumor necrosis factor alpha (TNF-α) and monocyte TNF-α receptor (TNFR1) expression following intense acute resistance exercise and subsequent recovery. Thirty (n = 30) resistance trained men (22.5 ± 2.7 y) performed an acute heavy resistance exercise protocol on three consecutive days followed by one of three recovery methods (CON, NMES, and CWI). Circulating TNF-α levels were assayed and TNFR1 expression on CD14+ monocytes was measured by flow cytometry measured PRE, immediately post (IP), 30-min post (30M), 24 h post (24H), and 48 h post (48H) exercise. Circulating TNF-α was elevated at IP (p = 0.001) and 30M (p = 0.005) and decreased at 24H and 48H recovery from IP in CON (p = 0.015) and CWI (p = 0.011). TNF-α did not significantly decrease from IP during recovery in NMES. TNFR1 expression was elevated (p < 0.001) at 30M compared to PRE and all other time points. No significant differences between groups were observed in TNFR1 expression. During recovery (24H, 48H) from muscle damaging exercise, NMES treatment appears to prevent the decline in circulating TNF-α observed during recovery in those receiving no treatment or CWI.

Inhalation of fine particulate matter during pregnancy increased IL-4 cytokine levels in the fetal portion of the placenta

This study aimed to verify the development of placental and systemic inflammation in rats exposed to fine particulate matter before or during pregnancy. Wistar rats were exposed to filtered air (control) or to a load of 600μg/m3 of fine particles in the air. The gene expression of IL-1β, IL-4, IL-6, IL-10, INF-γ, TNF-α and Toll-like receptor 4 in the placenta was evaluated. The serum and placental concentrations of IL-1β, IL-4, IL-6, IL-10, INF-γ and TNF-α were measured. The total and differential blood leukocyte and blood platelet count was assessed. Compared to control animals, IL-4 content was elevated in the fetal portion of the placenta in rats exposed to air pollution before and during pregnancy. Increased IL-4 suggests that a placental inflammatory reaction may have occurred in response to exposure to fine particulate matter and that this cytokine was responsible, among possibly others factors, for resolution of the inflammatory reaction.

Inhibition of neutrophil-dependent cytotoxicity for human endothelial cells by ACE inhibitors.

Angiotensin-converting enzyme inhibitors (ACEi) have immunomodulating properties and have been suggested to protect against endothelial injury, for example myocardial infarction and reperfusion injury. We tested whether two ACEi (captopril and enalapril), differing in a thiol group, protected human umbilical vein endothelial cells (HUVEC) from cytotoxicity induced by polymorphonuclear neutrophils (PMN) in vitro, when cells were activated by tumour necrosis factor-α (TNFα) or the arachidonate derivative lipoxin-A4 (LXA4 ), using separate cytotoxicity pathways. When (51) Cr labelled HUVEC were treated with captopril (0-500μm) or enalapril (0-100μm) for 2h and then activated by TNFα (100ng/ml) for 24h, a significant, dose-dependent reduction of (51) Cr release was observed. Similarly, captopril reduced (51) Cr release when LXA4 (0.1μm) was used to stimulate PMN for 4h. Among previously defined mechanisms of significance for the cytotoxic reaction, expression of ICAM-1, but not intracellular Ca(2+) changes in PMN or PMN adherence to HUVEC, were reduced by ACEi treatment. Moreover, both ACEi inhibited HUVEC surface expression of TNFα receptor I (but not II). Thus, these ACEi, particularly captopril, interfere with PMN-induced cytotoxicity for endothelial cells by modulating pro-inflammatory surface receptors, which is a novel effect that might be explored for further therapeutic approaches.

TNF-α receptor 1 expression predicts poor prognosis of diffuse large B-cell lymphoma, not otherwise specified.

We have previously shown that in tumor specimens from patients with diffuse large B-cell lymphoma, not otherwise specified (DLBCL, NOS), the tumor necrosis factor-α (TNF-α)-positive type correlates with a poorer prognosis compared with the TNF-α-negative type. In the present study, we further evaluated 60 lymphoma tissue specimens from patients with DLBCL, NOS by immunohistochemical staining with antibodies against TNF-α receptor 1 (TNFR1) and TNF-α receptor 2 (TNFR2). Our results demonstrated that 31 cases (52%) were positive and 29 (48%) were negative for TNFR1 and that the TNFR1-positive cases were significantly correlated with a poorer overall survival (OS; P=0.0006, log rank test) than the TNFR1-negative cases. The TNFR2-positive cases tended to have a poorer OS than the TNFR2-negative cases, although the difference was not significant. TNFR1 expression in tumor cells was a significant prognostic factor for OS and was independent of the International Prognostic Index (IPI). Among 31 TNF-α-positive DLBCL, NOS cases, 27 (87%) were positive and 4 (13%) were negative for TNFR1. Both TNF-α-positive and TNFR1-positive cases were significantly correlated with a poorer OS compared with the TNF-α-positive but TNFR1-negative cases. Twenty-seven cases (45%) with the TNF-α-positive and TNFR1-positive subtype of DLBCL, NOS had a poorer prognosis for OS and progression-free survival compared with the 33 cases (55%) with the remaining subtypes, and the TNF-α-positive and TNFR1-positive subtype of DLBCL, NOS was also shown to be independent of the IPI. In addition to the IPI, the prognosis of patients can be more accurately identified by evaluating both TNF-α and TNFR1 expression.

TNFα inhibits IGFBP-3 through activation of p38α and casein kinase 2 in human retinal endothelial cells.

We recently reported a reciprocal relationship between tumor necrosis factor alpha (TNFα) and insulin-like receptor growth factor binding protein 3 (IGFBP-3) in whole retina of normal and IGFBP-3 knockout mice. A similar relationship was also observed in cultured retinal endothelial cells (REC). We found that TNFα significantly reduced IGFBP-3 levels and vice-versa, IGFBP-3 can lower TNFα and TNFα receptor expression. Since IGFBP-3 is protective to the diabetic retina and TNFα is causative in the development of diabetic retinopathy, we wanted to better understand the cellular mechanisms by which TNFα can reduce IGFBP-3 levels. For these studies, primary human retinal endothelial cells (REC) were used since these cells undergo TNFα-mediated apoptosis under conditions of high glucose conditions and contribute to diabetic retinopathy. We first cultured REC in normal or high glucose, treated with exogenous TNFα, then measured changes in potential signaling pathways, with a focus on P38 mitogen-activated protein kinase alpha (P38α) and casein kinase 2 (CK2) as these pathways have been linked to both TNFα and IGFBP-3. We found that TNFα significantly increased phosphorylation of P38α and CK2. Furthermore, specific inhibitors of P38α or CK2 blocked TNFα inhibition of IGFBP-3 expression, demonstrating that TNFα reduces IGFBP-3 through activation of P38α and CK2. Since TNFα and IGFBP-3 are key mediators of retinal damage and protection respectively in diabetic retinopathy, increased understanding of the relationship between these two proteins will offer new therapeutic options for treatment.

Tumour necrosis factor-alpha participates on the endothelin-1/nitric oxide imbalance in small arteries from obese patients: role of perivascular adipose tissue

We assessed the impact of vascular and perivascular tumour necrosis factor-alpha (TNF-α) on the endothelin (ET)-1/nitric oxide (NO) system and the molecular pathways involved in small arteries from visceral fat of obese patients (Obese) and Controls. Isolated small arteries from 16 Obese and 14 Controls were evaluated on a pressurized micromyograph. Endogenous ET-1 activity was assessed by the ETA blocker BQ-123. TNF-α and NO were tested by anti-TNF-α infliximab (IFX) and N(ω)-nitro-l-arginine methylester (L-NAME). Gene and protein expression of TNF-α, ET-1, ETA, and ETB receptors were determined by RT-PCR and IHC on arterial wall and in isolated adipocytes. Obese showed a blunted L-NAME-induced vasoconstriction, which was potentiated by IFX, and an increased relaxation to BQ-123, unaffected by L-NAME but attenuated by IFX. Perivascular adipose tissue (PVAT) removal reversed these effects. Obese showed intravascular superoxide excess, which was decreased by apocynin (NAD(P)H oxidase inhibitor), L-NAME, and BQ-123 incubations, and abolished by IFX. An increased vascular expression of ET-1, ETA, and ETB receptors, and higher vascular/perivascular TNF-α and TNF-α receptor expression were also detected. The arterial expression and phosphorylation of c-Jun N-terminal kinase (JNK) were higher in Obese vs. Controls, and downregulated by IFX. In small arteries of Obese, PVAT-derived TNF-α excess, and an increased vascular expression of ET-1 and ETA receptor, contribute to the ET-1/NO system imbalance, by impairing tonic NO release. Reactive oxygen species excess, via NAD(P)H oxidase activation, induces the endothelial nitric oxide synthase uncoupling, which in turn generates superoxide and impairs NO production. The up-regulated JNK pathway represents a crucial molecular signalling involved in this process.

The Effect of Single Nucleotide Polymorphisms in the Tumor Necrosis Factor-α Gene on Reproductive Performance and Immune Function in Dairy Cattle

The present study aimed to assess the effect of polymorphisms in the tumor necrosis factor α (TNF-α) promoter (A/A, A/G and G/G) and exons (T/T, T/C and C/C) on immune function and reproductive performance in dairy cows. The occurrence of the first postpartum ovulation within 3 weeks in the cows with the TNF-α promoter A/G and G/G genotypes was higher than in the A/A group. Among the different TNF-α exon genotypes, the occurrence of early first postpartum ovulation was higher in the T/C and C/C genotype groups than in the T/T group. Single nucleotide polymorphisms (SNPs) in the TNF-α gene did not affect the rate of artificial insemination (AI) or duration from parturition to next conception (days open). The apoptosis rate of polymorphonuclear leukocytes (PMNs) did not differ among the TNF-α promoter genotypes, but the PMN transmigration rate was significantly higher for the A/A and A/G genotypes than for the G/G genotype. Interleukin 8 (IL-8) mRNA expression in PMNs and peripheral blood mononuclear cells (PBMCs) before culture was significantly higher for the A/A genotype compared with the G/G genotype. There were no significant differences between the genotypes in the mRNA expression of TNF-α, IL-6, IL-1β, and toll-like receptor 4 (TLR4) in PMNs and PBMCs before and 4 h after culture. IL-8 and IL-1β production by PBMCs cultured for 4 h was significantly higher for the animals with the A/A genotype than for those with the G/G genotype. On the other hand, no significant difference was observed in IL-8 and IL-1β production by PMNs among different TNF-α genotypes. Taken together, these results suggest that SNP in the TNF-α gene affects immune function and reproductive performance in dairy cows.

Angiogenin reduces immune inflammation via inhibition of TANK-binding kinase 1 expression in human corneal fibroblast cells.

Angiogenin (ANG) is reportedly multifunctional, with roles in angiogenesis and autoimmune diseases. This protein is involved in the innate immune system and has been implicated in several inflammatory diseases. Although ANG may be involved in the anti-inflammatory response, there is no evidence that it has direct anti-inflammatory effects. In this study we sought to determine whether ANG has an anti-inflammatory effect in human corneal fibroblasts (HCFs) exposed to media containing tumor necrosis factor-alpha (TNF-α). We found that ANG reduced the mRNA expression of interleukin-1 beta (IL-1β), -6, -8 and TNF-α receptors (TNFR) 1 and 2. In contrast, ANG increased the mRNA expression of IL-4 and -10. Protein levels of TANK-binding kinase 1 (TBK1) were reduced by ANG in HCFs treated with TNF-α. Moreover, ANG diminished the expression of IL-6 and -8 and monocyte chemotactic protein- (MCP-) 1. The protein expression of nuclear factor-κB (NF-κB) was downregulated by ANG treatment. These findings suggest that ANG suppressed the TNF-α-induced inflammatory response in HCFs through inhibition of TBK1-mediated NF-κB nuclear translocation. These novel results are likely to play a significant role in the selection of immune-mediated inflammatory therapeutic targets and may shed light on the pathogenesis of immune-mediated inflammatory diseases.

Liver protective effect of ursodeoxycholic acid includes regulation of ADAM17 activity

BackgroundUrsodeoxycholic acid (UDCA) is used to treat primary biliary cirrhosis, intrahepatic cholestasis, and other cholestatic conditions. Although much has been learned about the molecular basis of the disease pathophysiology, our understanding of the effects of UDCA remains unclear. Possibly underlying its cytoprotective, anti-apoptotic, anti-oxidative effects, UDCA was reported to regulate the expression of TNFα and other inflammatory cytokines. However, it is not known if this effect involves also modulation of ADAM family of metalloproteinases, which are responsible for release of ectodomains of inflammatory cytokines from the cell surface. We hypothesized that UDCA modulates ADAM17 activity, resulting in amelioration of cholestasis in a murine model of bile duct ligation (BDL).MethodsThe effect of UDCA on ADAM17 activity was studied using the human liver hepatocellular carcinoma cell line HepG2. Untransfected cells or cells ectopically expressing human ADAM17 were cultured with or without UDCA and further activated using phorbol-12-myristate-13-acetate (PMA). The expression and release of ADAM17 substrates, TNFα, TGFα, and c-Met receptor (or its soluble form, sMet) were evaluated using ELISA and quantitative real-time (qRT) PCR. Immunoblotting analyses were conducted to evaluate expression and activation of ADAM17 as well as the level of ERK1/2 phosphorylation after UDCA treatment. The regulation of tissue inhibitor of metalloproteinases-1 (TIMP-1) by UDCA was studied using zymography and qRT-PCR. A mouse model of acute cholestasis was induced by common BDL technique, during which mice received daily orogastric gavage with either UDCA or vehicle only. Liver injury was quantified using alkaline phosphatase (ALP), relative liver weight, and confirmed by histological analysis. ADAM17 substrates in sera were assessed using a bead multiplex assay.ResultsUDCA decreases amount of shed TNFα, TGFα, and sMet in cell culture media and the phosphorylation of ERK1/2. These effects are mediated by the reduction of ADAM17 activity in PMA stimulated cells although the expression ADAM17 is not affected. UDCA reduced the level of the mature form of ADAM17. Moreover, UDCA regulates the expression of TIMP-1 and gelatinases activity in PMA stimulated cells. A BDL-induced acute cholangitis model was characterized by increased relative liver weight, serum levels of ALP, sMet, and loss of intracellular glycogen. UDCA administration significantly decreased ALP and sMet levels, and reduced relative liver weight. Furthermore, hepatocytes of UDCA-treated animals retained their metabolic activity as evidenced by the amount of glycogen storage.ConclusionsThe beneficial effect of UDCA appears to be mediated in part by the inhibition of ADAM17 activation and, thus, the release of TNFα, a strong pro-inflammatory factor. The release of other ADAM17 substrates, TGFα and sMet, are also regulated this way, pointing to a general impact on the release of ADAM17 substrates, which are pivotal for liver regeneration and function. In parallel, UDCA upregulates TIMP-1 that in turn inhibits matrix metalloproteinases, which destroy the hepatic ECM in diseased liver. This control of extracellular matrix turnover represents an additional beneficial path of UDCA treatment.