MASP-1 of the complement system alters fibrinolytic behaviour of blood clots Publication date: October 2019 Source: Molecular Immunology, Volume 114 Author(s): Lorenz Jenny, Danilo Noser, Julie Brogaard Larsen, József Dobó, Péter Gál, Gábor Pál, Verena Schroeder Abstract Background The lectin pathway serine protease mannan-binding lectin-associated serine protease 1 (MASP-1) has been demonstrated to be a major link between complement and coagulation, yet little is known about its interactions with the fibrinolytic system. The aim of this work was to assess the effects of MASP-1 on fibrin clot lysis in different experimental settings. Methods Rotational thrombelastometry was used to evaluate the effect of MASP-1 on the lysis of clots formed in whole blood under static conditions. Whole blood clots were also formed in the presence and absence of MASP-1 under flow conditions in the Chandler loop and their lysis was analysed separately by fluorescence release of incorporated labelled fibrin. Real-time observation by laser scanning confocal microscopy was used to investigate the lysis of plasma clots where MASP-1 was present either during clot formation or lysis. Cleavage of tPA or plasminogen by MASP-1 was analysed by gel electrophoresis. We performed a turbidimetric clot lysis assay in the presence and absence of the MASP-1 inhibitor SGMI-1 (Schistocerca gregaria protease inhibitor (SGPI)-based MASP inhibitor-1) to evaluate the effect of endogenous MASP-1 in normal plasma and plasma samples from sepsis patients. Results In the thrombelastometric experiments, where MASP-1 was present during the entire clotting and lysis process, MASP-1 had a significant profibrinolytic effect and accelerated clot lysis. When clots were formed in the presence of MASP-1 under flow in the Chandler loop, the effects on fibrinolysis were heterogenous with impaired fibrinolysis in some individuals (n = 5) and no (n = 3) or even the opposite effect (n = 2) in others. In plasma clot lysis observed by confocal microscopy, lysis was prolonged when MASP-1 was added to the lysis solution, yet there was no difference in lysis time when MASP-1 was present during clot formation. When MASP-1 was incubated with tPA or plasminogen, respectively, cleavage of single-chain tPA into two-chain tPA and a slight reduction of plasminogen were observed. SGMI-1 significantly prolonged clot lysis in the turbidimetric clot lysis assay suggesting that MASP-1 accelerated lysis in plasma samples. Conclusion MASP-1 is able to alter the susceptibility of blood clots to the fibrinolytic system. MASP-1 has complex, mostly promoting effects on fibrinolysis with high inter-individual variation. Interactions of MASP-1 with the fibrinolytic system may be relevant in the development and therapy of cardiovascular and thrombotic diseases.

LncRNA MALAT1 cessation antagonizes hypoxia/reoxygenation injury in hepatocytes by inhibiting apoptosis and inflammation via the HMGB1-TLR4 axis Publication date: August 2019 Source: Molecular Immunology, Volume 112 Author(s): Yong Zhang, Huijuan Zhang, Zhenni Zhang, Siyuan Li, Wenjun Jiang, Xue Li, Jianrui Lv Abstract Hepatic ischemia-reperfusion (I/R) injury frequently occurs after liver transplantation, stroke, and trauma, resulting in organ dysfunction and failure. Hepatocyte apoptosis and inflammation are identified as the hallmarks of liver I/R injury. Long non-coding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is induced following hypoxia or ischemic stimulation, and exerts the contradictory roles in various injury progression. However, its role and mechanism lying beneath hepatic I/R remains ill defined. In this study, elevation of MALAT1 expression was corroborated in human hepatocytes under hypoxia/reoxygenation (H/R)H/R condition. Of interest, depression of MALAT1 blunted H/R-inhibited cell viability, and counteracted lactate dehydrogenase (LDH) and malondialdehyde release. Additionally, MALAT1 cessation antagonized H/R-evoked cell apoptosis and caspase-3 activity. Simultaneously, the increased inflammatory reaction triggered by H/R stimulation was also abrogated following MALAT1 suppression by reducing pro-inflammatory cytokine transcripts and productions including IL-1β and TNF-α. Mechanistically, H/R exposure activated the pathway of high-mobility group box1 (HMGB1)-TLR4, which was muted after MALAT1 inhibition. More importantly, elevation of HMGB1 reversed MALAT1 down-regulation-mediated inhibition in cell injury and inflammation. Moreover, blocking the TLR4 signaling also ameliorated H/R-evoked hepatocyte apoptosis and inflammatory response. Consequently, these data suggest that MALAT1 may aggravate hepatic I/R injury by regulating the HMGB1-TLR4-triggered cell apoptosis and inflammation, implying a promising therapeutic strategy to fight liver I/R injury.

Deficiency of programmed cell death 4 affects the balance of T cell subsets in hyperlipidemic mice Publication date: August 2019 Source: Molecular Immunology, Volume 112 Author(s): Yang Jiang, Qi Gao, Li-Yang Wang, Tian Ma, Fa-Liang Zhu, Qun Wang, Fei Gao, Chun Guo, Li-Ning Zhang Abstract Programmed cell death 4 (Pdcd4) was found to be related to apoptosis upon first discovery. It was later found to play the role of tumor suppressor gene in a variety of tumors by inhibiting transcription and translation. Recently, it has been proposed that it may play an important role in some inflammatory diseases and in the immune response. In our previous study, deficiency of Pdcd4 was found to attenuate the formation of atherosclerotic plaques. This might be because deficiency of Pdcd4 may increase IL-10 expression and lipoautophagy by macrophages and attenuate the formation of foam cells. However, the effect of Pdcd4 on the subsets of T cells in hyperlipidemic mice still remained unclear. In the present study, results showed that Pdcd4 deficiency decreased the percentage of CD8+ T cells and increased that of regulatory T cells (Tregs) under hyperlipidemic conditions both in vitro and in vivo, which may be due to the reduced expression of co-stimulatory molecules CD28 and CD137, and the enhancive expression of co-inhibitory molecules CTLA-4. These results indicated that endogenous Pdcd4 promotes immune response mediated by T cells through regulation of the co-stimulatory molecules expression, which may contribute to the development of advanced atherosclerotic plaques. The current work provides new data to understand the role of Pdcd4 in different T cell subsets under hyperlipidemic microenvironment.

P2X4 receptor as a modulator in the function of P2X receptor in CD4+ T cells from peripheral blood and adipose tissue Publication date: August 2019 Source: Molecular Immunology, Volume 112 Author(s): Victor Manuel Ruiz-Rodríguez, Juan Diego Cortes-García, Margarita de Jesús Briones-Espinoza, Eduardo Rodríguez-Varela, Mariela Vega-Cárdenas, Arturo Gómez-Otero, Mariana Haydee García-Hernández, Diana Patricia Portales-Pérez Abstract Obesity is characterized by immune cell infiltration and inflammation. Purinergic receptors such as P2X1, 4 and 7 are expressed on immune cells and their activation contributes with an inflammatory response. However, the simultaneous expression of P2X1, 4 and 7 during overweight or obesity have not been described. Therefore, the aim of this study was to determine single and simultaneously expression and function of the P2X1, 4 and 7 receptors in lymphocytes and CD4 + T cells from peripheral blood (PB) and adipose tissue (AT). Our results showed a higher expression of the P2X4 receptor on CD4 + T cells from PB regarding P2X7 and P2X1 receptor expression. In addition, P2X4 receptor expression on CD4 + T cells from PB and AT was increased in individuals with BMI ≥ 25 Kg/m2. Moreover, a higher simultaneous expression of the P2X4 and P2X7 receptors on CD4 + T cells from AT compared to CD4 + T cells expressing P2X1 and P2X7 receptors simultaneously. Besides, CD4 + T cells expressing P2X4 and P2X7 receptors from PB and AT were augmented in individuals with BMI ≥ 25 Kg/m2. In addition, the percentage of lymphocytes and also CD4 + T cells expressing P2X4 receptor were elevated both in PB and AT compared to cells expressing P2X7 or P2X1. However, CD4 + T cells expressing P2X4 and P2X7 were augmented in AT compared to PB. The function of the receptors showed a lower shedding of CD62 L in adipose tissue mononuclear cells (ATMC) compared with peripheral blood mononuclear cells (PBMC) and a greater participation of P2X4 in the mobilization of intracellular calcium. We concluded that it was possible to determine for the first time the simultaneous expression of purinergic receptors in ATMC, where the P2X4 receptor has a greater participation in the activation of CD4 + T cells possibly modulating the function of the other two receptors.

N-terminal diversity of Litopenaeus vannamei hemocyanin and immunity Publication date: August 2019 Source: Molecular Immunology, Volume 112 Author(s): Jiaohong Fan, Xianmei Li, Hui Lu, Ruihong Lin, Jude Juventus Aweya, Yueling Zhang Abstract Hemocyanin is primarily a respiratory copper-containing glycoprotein present in the hemolymph of mollusks and arthropods. Recently, hemocyanin has attracted huge research interest due to its multifunctionality and polymorphism. Most previous immune-related studies on shrimp hemocyanin have focused on the C-terminal. Moreover, we previously reported that the C-terminal domain of Litopenaeus vannamei hemocyanin possesses single nucleotide polymorphisms (SNPs), but little is known about the molecular diversity of the N-terminal domain. In the current study, diversity within the N-terminal domain of L. vannamei hemocyanin (LvHMC-N) was explored using bioinformatics and molecular biology techniques as well as immune challenge. Twenty-five LvHMC-N variants were identified using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) and DNA sequencing, with multiple sequence alignment showing that the 25 variants shared 87%–99 % sequence homology with LvHMC (AJ250830.1). In different shrimp individuals and different shrimp tissues (i.e., hemocytes, stomach, muscle and hepatopancreas), the LvHMC-N variants were expressed differently. Pathogen challenge could modulate the molecular diversity of LvHMC-N, as three LvHMC-Nr variants (LvHMC-Nr1, LvHMC-Nr2 and LvHMC-Nr3) were identified by sequencing following Vibrio parahaemolyticus challenge. Most importantly, recombinant proteins of these three variants (rLvHMC-Nr1, rLvHMC-Nr2 and rLvHMC- Nr3) had relatively high in vitro agglutinative activities against V. parahaemolyticus, Vibrio alginolyticus and Streptoccocus iniae. Our present data indicates that the N-terminus of L. vannamei hemocyanin also possess molecular diversity, which seems to be associated with immune resistance to pathogenic infections.

ENEA, a peach and apricot IgE-binding protein cross-reacting with the latex major allergen Hev b 5 Publication date: August 2019 Source: Molecular Immunology, Volume 112 Author(s): Ivana Giangrieco, Teresa Ricciardi, Claudia Alessandri, Lucia Farina, Roberta Crescenzo, Lisa Tuppo, Michela Ciancamerla, Chiara Rafaiani, Maria Livia Bernardi, Anna Filomena Digilio, Beatrice Cobucci-Ponzano, Maurizio Tamburrini, Adriano Mari, Maria Antonietta Ciardiello Abstract Peach and apricot can cause allergic reactions with symptoms ranging from mild to very severe, including anaphylaxis. Sometimes subjects allergic to fruits of the Prunus genus have been reported to be also allergic to rubber latex products. The objective of this study is the characterization of a newly identified peach and apricot protein showing similarities with the allergens Hev b 5 from rubber latex and Man e 5 from manioc. This protein has been named ENEA on the basis of the single letter amino acid code of the first four N-terminal residues of the isolated molecule. It has been found in very variable amounts in different peach cultivars and batches. ENEA was isolated from peach pulp extracts by chromatographic separations and identified by direct protein sequencing. At that time, the full length sequence was available only for the homologous protein of the taxonomically closely related apricot, which was produced as a recombinant molecule in Escherichia coli. The following availability of the full length sequence of peach ENEA revealed a very high identity (97%) with the apricot homolog. Similarly to Hev b 5 and to Man e 5, the structural characterization indicated that ENEA is an intrinsically disordered protein. The immunological properties, investigated by dot blotting, the ABA system and the FABER test, showed that ENEA is recognized by specific IgE of allergic patients. In a selected population of 31 patients reporting allergic reactions to peach fruit and/or IgE positive to Hev b 5, 28 and 27 subjects resulted co-sensitized to rENEA and Hev b 5 in the ABA and ISAC test, respectively. In a random population of 3305 suspected allergic patients, analyzed with the FABER test, 17 of them were sensitized to rENEA and 10 of them were also positive to Hev b 5. In addition, both the natural molecule from peach and the recombinant protein of apricot partially inhibited the IgE binding to Hev b 5. In conclusion, a new peach and apricot IgE-binding protein, cross-reacting with the major latex allergen Hev b 5, has been identified. Its variable concentration in the fruit might explain some occasionally occurring allergic reactions. The apricot molecule has recently been registered by the WHO/IUIS Allergen Nomenclature Sub-Committee with the allergen name Pru ar 5. The recombinant form of apricot ENEA, now available, will contribute to allergy diagnosis.

Sequence features of variable region determining physicochemical properties and polyreactivity of therapeutic antibodies Publication date: August 2019 Source: Molecular Immunology, Volume 112 Author(s): Maxime Lecerf, Alexia Kanyavuz, Sébastien Lacroix-Desmazes, Jordan D. Dimitrov Abstract Therapeutic antibodies have transformed the clinical practice. Not surprisingly, development of antibody therapeutics is currently the main focus of the biotechnology industry. Nonetheless, the development process is complex, and many antibodies do not reach the clinic. Reasons for the failures include, undesired binding behavior (polyreactivity), low stability, poor expression yields, unfavorable pharmacokinetics etc. Numerous studies have proposed different analytical methods for assessment of physicochemical parameters of antibodies and identification of problematic molecules at early stages of the development process. These studies, however, have not addressed the basic mechanistic question of how sequence features of variable regions determinate the different biophysical characteristics and the binding behavior of the antibodies. In a recent study, Jain et al assessed 12 biophysical qualities of 137 monoclonal therapeutic antibodies. We used the raw data from this comprehensive study to perform correlation analyses of different biophysical measurables with various sequence features of variable regions of the antibodies - number of mutations, length of hypervariable loops, and frequency of amino acid residue types. The obtained data reveled significant relationships between the sequence characteristics of the variable domains and different physiochemical properties of antibodies. The data from this study can assist in design of a set of criteria for early identification of antibodies with developability issues. Moreover, our findings provide novel fundamental insights into the sequence-function relationship of antibodies.

Defining specific allergens for improved component-resolved diagnosis of shrimp allergy in adults Publication date: August 2019 Source: Molecular Immunology, Volume 112 Author(s): Elecia B. Johnston, Sandip D. Kamath, Swati P. Iyer, Kunal Pratap, Shaymaviswanathan Karnaneedi, Aya C. Taki, Roni Nugraha, Patrick M. Schaeffer, Jennifer M. Rolland, Robyn E. O’Hehir, Andreas L. Lopata Abstract Shrimp is one of the predominant causes of food allergy among adults, often presenting with severe reactions. Current in vitro diagnostics are based on quantification of patient specific-IgE (sIgE) to shrimp extract. Tropomyosin is the known major shrimp allergen, but IgE sensitisation to other allergens is poorly characterised. In this study, the binding of IgE to various shrimp allergens, additional to tropomyosin, was investigated using sera from 21 subjects who had clinical reactions to one or more shellfish species. Total shrimp-sIgE was quantified using ImmunoCAP, while allergen-sIgEs were quantified using immunoblotting and mass spectrometry, and immuno-PCR to recombinant shrimp tropomyosin. Sixty-two percent of subjects (13/21) were positive to shrimp by ImmunoCAP. IgE from 43% of subjects (9/21) bound tropomyosin, while an additional 29% of subjects (6/21) demonstrated IgE-binding solely to other shrimp allergens, including sarcoplasmic calcium-binding protein, arginine kinase and hemocyanin. Furthermore, IgE sensitisation to other shrimp allergens was demonstrated in 50% of subjects (4/8) who were ImmunoCAP negative. The lack of standardised shrimp allergens and inadequacy of current extracts for shrimp allergy diagnosis is highlighted by this study. Comprehensive knowledge of less studied allergens and their inclusion in component-resolved diagnostics will improve diagnostic accuracy, benefitting the wider population suffering from shellfish allergy.

Interleukin-37 sensitize the elderly type 2 diabetic patients to insulin therapy through suppressing the gut microbiota dysbiosis Publication date: August 2019 Source: Molecular Immunology, Volume 112 Author(s): Tianyi Li, Hua Li, Weifang Li, Sufang Chen, Tao Feng, Wenjun Jiao, Cong Wu, Jie Dong, Yuanyuan Li, Sujun Li, Ming Feng, Xiaowen Wei Abstract Objective The morbidity and prevalence of type 2 diabetes mellitus (DM) are increasing in the elderly population. Interleukin 37 (IL-37) play important roles in anti-inflammatory and anti-bacteria immune responses, but its role in the development of type 2 DM in the elderly is unclear. Therefore, we investigated whether IL-37 is associated with type 2 DM in the elderly and the underlying mechanism. Methods Hospitalized patients (aged 65–95 years) with recently diagnosed type 2 diabetes mellitus were studied retrospectively and compared with healthy subjects without glucose metabolism abnormalities. A diabetic mouse model was established by feeding ob/ob mice (C57BL/6) a high-fat, carbohydrate-free diet. Plasma glucose and insulin levels were determined by glucose oxidase assay and radioimmunoassay, respectively. The IL-37 expression level was determined by real-time PCR, western blot and ELISA (Enzyme-linked immunoassay). Results Statistic analysis showed that the IL-37 level was significantly associated with type 2 DM and insulin resistance in the elderly. The patients were then divided into insulin therapy sensitive and resistant group according to their response to insulin therapy. Data showed that the IL-37 was highly expressed in the insulin therapy sensitive group. And this was related to the less severe gut microbiota dysbiosis. In the mice model, overexpressing the IL-37 could suppress the gut microbiota dysbiosis and also the diabetes development. Conclusion Thus our results showed that higher IL-37 was associated with increased insulin sensitive in elderly type 2 DM patients through suppressing the gut microbiota dysbiosis.

Ablation of core fucosylation attenuates the signal transduction via T cell receptor to suppress the T cell development Publication date: August 2019 Source: Molecular Immunology, Volume 112 Author(s): Wei Liang, Shanshan Mao, Ming Li, Nianzhu Zhang, Shijie Sun, Hui Fang, Jianing Zhang, Jianguo Gu, Jingyu Wang, Wenzhe Li Abstract Precise glycosylation plays a crucial and distinctive role in thymic T cell development. The core fucosylation is dramatically up-regulated at the transition from CD4−CD8− (DN) to CD4+CD8+ (DP) in the thymic development. Ablation of core fucosylation in T cells did reduce the size of the thymus due to a significant loss of CD4+ SP, CD8+ SP and DP thymocytes in core fucosyltransferase (Fut8) knockout (Fut8−/−) mice. T cell receptors (TCRs) are heavily core fucosylated glycoproteins. Loss of core fucosylation of TCR contributed to the reduced phosphorylation of ZAP70 (pZAP70) in Fut8−/− DP cells was observed. Compare to the Fut8+/+OT-II DP thymocytes, pZAP70 was significantly reduced in Fut8−/− OT-II DP thymocytes with OVA323–339 stimulation. Also, the pZAP70 of Fut8+/+OT-I DP thymocytes with OVA257–264 stimulation was remarkably attenuated by treatment of the fucosidase. Upon anti-CD3/CD28 Abs stimulation, the increased apoptosis was found in Fut8−/− thymocytes compared with Fut8+/+ thymocytes. Moreover, the TCRhiCD69hi (post-positive selection thymocytes) was markedly depleted in the Fut8−/− thymus without any stimulation. The expression of CD5 was significantly down-regulated on the DP cells in the Fut8−/− thymus. Our results therefore demonstrate that ablation of core fucosylation results in the abnormal T cell development due to the attenuated signaling via TCR.