IFN-γ is reciprocally involved in the concurrent development of organ-specific autoimmunity in the liver and stomach

Interferon (IFN)-γ acts as a critical proinflammatory mediator in autoimmune processes, whereas it exerts regulatory functions to limit tissue damage associated with inflammation. However, a detailed understanding of the complex roles of IFN-γ in the development of organ-specific autoimmunity is still lacking. Recently, we found that programmed cell death 1-deficient mice thymectomized 3 days after birth (NTx–PD-1^{? / ?} mice) concurrently developed autoimmune hepatitis (AIH) and autoimmune gastritis (AIG). In this study, we investigated the roles of IFN-γ in the development of AIH and AIG in this mouse model. In NTx–PD-1^{? / ?} mice, serum levels of IFN-γ were markedly elevated. Neutralization of IFN-γ prevented the development of AIG. However, the same treatment exacerbated hepatic T-cell infiltration in AIH. Because of the loss of anti-proliferative effects by IFN-γ, neutralization of IFN-γ increased T-cell proliferation in the spleen and liver, resulting in exacerbated T-cell infiltration in the liver. On the other hand, in the development of AIG, CD4⁺ T-cell migration into the gastric mucosa is essential for induction. CCL20 expression was up-regulated in the gastric mucosa, and anti-CCL20 suppressed CD4⁺ T-cell infiltration into the gastric mucosa. Importantly, anti-IFN-γ suppressed CCL20 expression and infiltration of CD4⁺ T cells in the gastric mucosa, whereas in vivo injection of recombinant IFN-γ up-regulated CCL20 expression in the stomach, suggesting that IFN-γ is critically involved in CD4⁺ T-cell accumulation in AIG by up-regulating local CCL20 expression. In conclusion, IFN-γ is involved differently in the development of AIH and of AIG. IFN-γ negatively regulates T-cell proliferation in fatal AIH, whereas it initiates development of AIG. These findings imply that increased production of IFN-γ induced by an organ-specific autoimmunity may trigger the concurrent development of another organ-specific autoimmune disease.     

Determination of dead-layer variation in HPGe detectors

The dead-layer uniformity of the top surface of two high purity germanium detectors has been studied using a novel automated scanning set-up that allows a fine-grained topography of a detector's top and lateral surfaces. Comparisons between measurements and Monte Carlo simulations allowed implementation of a dead-layer variation into the detector model, which reproduces the measurements results. The effect of the non-uniform dead-layer on activity determinations based on low-energy γ-rays (i.e. below ~100 keV) has been determined to be of the order of 10% or more.     

Contrasting associations of polymorphisms in FcγRIIa and DC-SIGN with the clinical presentation of dengue infection in a Mexican population

Dengue virus (DENV) causes a spectrum of illness from asymptomatic infection, to a mild febrile illness, to occasional more severe complications including hemorrhage and shock. Dengue is endemic in the state of Morelos, Mexico. Two single nucleotide polymorphisms (SNPs), rs1801274 of FcγRIIa and rs4804803 of DC-SIGN, have been associated with protection from or susceptibility to severe dengue infection. Both of these polymorphisms are located in genes for receptors with important roles in dengue pathogenesis, and their relationship with the clinical presentation of dengue infection in Mexican populations is unknown. In this study, real-time PCR was used to characterize the distribution of rs1801274 and rs4804803 in subjects with asymptomatic dengue infection (n = 145), uncomplicated dengue (n = 67), and severe dengue (n = 36) in Morelos. In contrast with previous studies, the histidine (A) variant of rs1801274 was associated with more mild infection: carrying the histidine allele (either homozygous or heterozygous) was associated with protection from symptomatic infection compared with asymptomatic (OR 0.51, p = 0.038). Histidine homozygotes were also less likely to present severe dengue (OR 0.34, p = 0.05). Logistic regression models confirm this association (OR 0.48, p = 0.04) and also indicate that the G allele of rs4804803 is associated with symptomatic dengue (OR 2.3, p = 0.08), after accounting for other biological factors including history of infection. This variant was rare in this study population, with a frequency of 5.4%. These findings reflect the complexity of influences on the development of severe dengue infection. The inclusion of asymptomatic infections and adjusted case definitions likely do not explain the entire disparity with previous findings. Interactions with other polymorphisms may explain why the association of rs1801274 is reversed in this population compared to others. This study demonstrates the importance of genetic association studies in multiple genetically distinct populations.     

Association between peroxisome proliferator-activated receptor-γ gene polymorphism (Pro12Ala) and Helicobacter pylori infection in gastric carcinogenesis

Abstract

Objective. Helicobacter pylori infection is accompanied by inflammatory processes leading to peptic ulcer and gastric cancer in the minority of infected individuals. The interaction between H. pylori virulence factors, host defense mechanisms and environmental factors determine the outcome of clinical manifestations. One of the host factors involved in the processes of inflammation and carcinogenesis is the peroxisome proliferator-activated receptor-γ (PPAR-γ) molecule. The present case–control study aimed to determine polymorphism of PPAR-γ gene and its association with H. pylori infection and gastrointestinal diseases (peptic ulcer and non-cardia gastric cancer) in Iranian patients. Materials and methods. One hundred and fifty-five patients with upper gastrointestinal diseases (76 peptic ulcer and 79 non-cardia gastric cancer) and 152 matched controls were genotyped for PPAR-γ gene polymorphism (Pro12Ala) by the PCR–RFLP method. Infection with H. pylori was confirmed by histology, the rapid urease test (RUT) and ELISA assay (IgG anti-H. pylori). Results. The frequency of PPAR-γ G (Ala 12) allele was significantly higher in H. pylori positive patients with non-cardia gastric cancer than in controls (22.8% vs. 3.9%, p = 0.027; OR = 3.28; 95% CI = 1.21–8.89), But there was no significant difference without infection (p = 0.7). Moreover, the PPAR-γ polymorphism was not associated with peptic ulcer in the presence or absence of H. pylori infection. Conclusion. Our results indicated PPAR-γ G allele may be an important contributor to non-cardia gastric cancer in Iranian H. pylori infected patients.     

Scintillation proximity assay in lead discovery

Background: Scintillation proximity assay (SPA) is a homogeneous scintillant bead-based platform for the measurement of biological processes and plays an important role in the identification of active chemical entities in drug discovery. Objective: The design and development of solid-phase SPA approaches are examined and compared with alternative non-radiometric fluorescence-based technologies. Methods: This review provides background on the principle of SPA and its application to biomolecular interactions from a variety of biological sources. Conclusion: The SPA approach is well suited to the demands of commercial high volume automation and assay miniaturization for target-based high-throughput screening campaigns on synthetic and natural product libraries as well as for benchtop characterization and confirmation studies. In the near future, innovations in the way SPA and fluorescence-based screening strategies are multiplexed will improve our comprehensive understanding of cellular system biology and dramatically advance the lead discovery process for the treatment of complex target-related disorders.     

Induction of apoptosis by heat and γ-radiation in a human lymphoid cell line; role of mitochondrial changes and caspase activation

Purpose: The aim of the study was to investigate the molecular mechanisms involved in apoptosis of human promyelocytic cells (HL60) induced by hyperthermia and to compare this to radiation-induced apoptosis as a reference model.

Materials and methods: Apoptosis of HL60 cells was induced by heat-treatment (43°C during 1?h) or by γ-radiation (8?Gy) and followed at increasing time periods after treatment with Annexin V binding to phosphatidylserine (PS). The transition of the mitochondrial membrane potential (Δψ_m) was estimated by the extent of mitochondrial JC-1 uptake. Bcl-2 and Bax protein expression levels were monitored using fluorescent-labelled antibodies. Caspase activation was studied using a fluorochrome-labelled pan-caspase inhibitor (FLICA), which also allowed one to study the kinetics of the apoptotic cascade.

Results: After heat-treatment or irradiation of HL60 cells, a decreased Δψ_m as well as PS membrane expression were detectable after 8?h. Bcl-2 and Bax protein expression levels were decreased and increased, respectively, 1?h after heat-treatment or irradiation. The apoptotic rate of HL60 cells, as measured by the FLICA binding, was faster with heat-treatment as compared to γ-irradiation. Addition of a pan-caspase inhibitor prevented PS externalization after heat-treatment but not after irradiation. The presence of a pan-caspase inhibitor did not influence the decrease of Δψ_m both after heat-treatment and γ-irradiation. However, the addition of the specific caspase-2 inhibitor zVDVAD-fmk prevented the mitochondrial breakdown after heat-treatment. Inhibition of caspase-2 had no effect on the γ-irradiation induced apoptosis.

Conclusion: These results suggest that the commitment to apoptosis in HL60 cells after heat-treatment is started by mitochondrial membrane transition involving the Bcl-2 family members and is mainly executed in a caspase-dependent pathway. The results suggest that caspase-2 plays a key role in the heat-induced apoptosis.     

Peroxisome proliferator-activated receptor-γ ligands as investigational modulators of angiogenesis

PPAR-γ ligands constitute important insulin sensitizers that have already been approved for the treatment of human metabolic disorders. They also exert pleiotropic effects on cell proliferation and cancer and are now being explored in preclinical studies. Angiogenesis constitutes a multifaceted process that is implicated in tumor development and other benign disease states that are associated with diabetes. Recent data have further extended the crucial role of PPAR-γ ligands as potential angiogenesis modulators, in vitro and in vivo. This review summarizes the latest knowledge of the role of PPAR-γ ligands in angiogenesis that are related to both malignant and non-malignant disease states. Taking into careful consideration the data so far, PPAR-γ could be considered as a therapeutic target for diverse disease states in which excessive angiogenesis is implicated, including cancer and diabetes complications.     

Inhibition of Notch signalling has ability to alter the proximal and distal TCR signalling events in human CD3+ αβ T-cells

The Notch signalling pathway is an important regulator of T cell function and is known to regulate the effector functions of T cells driven by T cell receptor (TCR). However, the mechanism integrating these pathways in human CD3⁺ αβ T cells is not well understood. The present study was carried out to investigate how Notch and TCR driven signalling are synchronized in human αβ T cells. Differential expression of Notch receptors, ligands, and target genes is observed on human αβ T cells which are upregulated on stimulation with α-CD3/CD28 mAb. Inhibition of Notch signalling by GSI-X inhibited the activation of T cells and affected proximal T cell signalling by regulating CD3-ζ chain expression. Inhibition of Notch signalling decreased the protein expression of CD3-ζ chain and induced expression of E3 ubiquitin ligase (GRAIL) in human αβ T cells. Apart from affecting proximal TCR signalling, Notch signalling also regulated the distal TCR signalling events. In the absence of Notch signalling, α-CD3/CD28 mAb induced activation and IFN-γ production by αβ T cells was down-modulated. The absence of Notch signalling in human αβ T cells inhibited proliferative responses despite strong signalling through TCR and IL-2 receptor. This study shows how Notch signalling cooperates with TCR signalling by regulating CD3-ζ chain expression to support proliferation and activation of human αβ T cells.     

熊去氧胆酸联合非诺贝特治疗PBC患者血清TGF-β、IFN-γ和IL-10水平变化*

目的 探讨熊去氧胆酸(UDCA)联合非诺贝特治疗原发性胆汁性胆管炎(PBC)患者血清转化生长因子-β(TGF-β)、γ-干扰素(IFN-γ)和白介素-10(IL-10)水平的变化。方法 2016年12月～2018年12月我科诊治PBC患者48例,随机将患者分为观察组(n=24)和对照组(n=24)。给予对照组患者UDCA治疗半年,给予观察组UDCA联合非诺贝特口服治疗半年。采用ELISA法检测血清TGF-β、IFN-γ和IL-10水平。使用FibroTouch行肝脏硬度测定(liver stiffness measurement, LSM)。结果 在治疗观察结束时,观察组血清谷丙转氨酶水平为(51.4±23.7)U/L,显著低于对照组【(74.9±21.2)U/L,P<0.05】,谷草转氨酶为(59.5±32.3)U/L,显著低于对照组【(81.3±35.8)U/L,P<0.05】,谷氨酰转肽酶水平为(95.7±31.8)U/L,显著低于对照组【(127.3±50.7)U/L,P<0.05】;观察组血清IFN-γ水平为(57.4±21.3)pg/mL,显著高于对照组【(39.7±23.7)pg/mL,P<0.05】,而血清TGF-β水平为(14.3±4.8)pg/mL,显著低于对照组【(23.6±3.5)pg/mL,P<0.05】;观察组血清免疫球蛋M(IgM)为(2.3±0.4)g/L,显著低于对照组【(3.1±0.9)g/L,P<0.05】, IgG水平为(11.3±1.8)g/L,显著低于对照组【(15.5±1.3)g/L,P<0.05】,IgA水平为(2.7±0.6)g/L,显著低于对照组【(3.5±0.2)g/L,P<0.05】;观察组患者LSM为(10.8±6.5)kPa,与对照组的(9.7±7.7)kPa比,无统计学差异(P>0.05)。结论 熊去氧胆酸联合非诺贝特联合治疗PBC患者可以明显改善血生化指标,可能与抑制了免疫球蛋白水平和提高了血清IFN-γ水平有关,其治疗的远期疗效还有待于观察。