A new preparation method of covalent annular nanodiscs based on MTGase.

The preservation of the native conformation and functionality of membrane proteins has posed considerable challenges. While detergents and liposome reconstitution have been traditional approaches, nanodiscs (NDs) offer a promising solution by embedding membrane proteins in phospholipids encircled by an amphipathic helical protein MSP belt. Nevertheless, a drawback of commonly used NDs is their limited homogeneity and stability. In this study, we present a novel approach to construct covalent annular nanodiscs (cNDs) by leveraging microbial transglutaminase (MTGase) to catalyze isopeptide bond formation between the side chains of terminal amino acids, specifically Lysine (K) and Glutamine (Q). This methodology significantly enhances the homogeneity and stability of NDs. Characterization of cNDs and the assembly of membrane proteins within them validate the successful reconstitution of membrane proteins with improved homogeneity and stability. Our findings suggest that cNDs represent a more suitable tool for investigating interactions between membrane proteins and lipids, as well as for analyzing membrane protein structures.

Accuracy of the No-Biopsy Approach for the Diagnosis of Celiac Disease in Adults: A Systematic Review and Meta-Analysis.

BACKGROUND & AIMS: Current international guidelines recommend duodenal biopsies to confirm the diagnosis of celiac disease in adult patients. However, growing evidence suggests that immunoglobulin A (IgA) anti-tissue transglutaminase (tTg) antibody levels ≥10 times the upper limit of normal (ULN) can accurately predict celiac disease, eliminating the need for biopsy. We performed a systematic review and meta-analysis to evaluate the accuracy of the no-biopsy approach to confirm the diagnosis of celiac disease in adults. METHODS: We systematically searched MEDLINE, EMBASE, Cochrane Library, and Web of Science from January 1998 to October 2023 for studies reporting the sensitivity and specificity of IgA-tTG ≥10×ULN against duodenal biopsies (Marsh grade ≥2) in adults with suspected celiac disease. We used a bivariate random effects model to calculate the summary estimates of sensitivity, specificity, and positive and negative likelihood ratios. The positive and negative likelihood ratios were used to calculate the positive predictive value of the no-biopsy approach across different pretest probabilities of celiac disease. The methodological quality of the included studies was evaluated using the QUADAS-2 tool. This study was registered with PROSPERO, number CRD42023398812. RESULTS: A total of 18 studies comprising 12,103 participants from 15 countries were included. The pooled prevalence of biopsy-proven celiac disease in the included studies was 62% (95% confidence interval [CI], 40%-83%). The proportion of patients with IgA-tTG ≥10×ULN was 32% (95% CI, 24%-40%). The summary sensitivity of IgA-tTG ≥10×ULN was 51% (95% CI, 42%-60%), and the summary specificity was 100% (95% CI, 98%-100%). The area under the summary receiver operating characteristic curve was 0.83 (95% CI, 0.77 - 0.89). The positive predictive value of the no-biopsy approach to identify patients with celiac disease was 65%, 88%, 95%, and 99% if celiac disease prevalence was 1%, 4%, 10%, and 40%, respectively. Between-study heterogeneity was moderate (I2 =30.3%), and additional sensitivity analyses did not significantly alter our findings. Only 1 study had a low risk of bias across all domains. CONCLUSION: The results of this meta-analysis suggest that selected adult patients with IgA-tTG ≥10×ULN and a moderate to high pretest probability of celiac disease could be diagnosed without undergoing invasive endoscopy and duodenal biopsy.

Increased Osteoclastogenesis in Absence of TG2 Is Reversed by Transglutaminase Inhibition-Evidence for the Role for TG1 in Osteoclast Formation.

Osteoclasts are multinucleated, bone-resorbing giant cells derived from monocyte-macrophage cell lines. Increased bone resorption results in loss of bone mass and osteoporosis. Osteoclast and bone marrow macrophages have been shown to express three TG enzymes (TG2, Factor XIII-A, and TG1) and TG activity to regulate osteoclast differentiation from bone marrow macrophages in vitro. In vivo and in vitro studies have demonstrated that the deletion of TG2 causes increased osteoclastogenesis and a significant loss of bone mass in mice (Tgm2-/- mice). Here, we confirm that TG2 deficiency results in increased osteoclastogenesis in vitro and show that this increase can be reversed by a TG inhibitor, NC9, suggesting that other TGs are responsible for driving osteoclastogenesis in the absence of TG2. An assessment of total TG activity with 5-(biotinamido)-pentylamine, as well as TG1 and FXIII-A activities using TG-specific Hitomi peptides (bK5 and bF11) in Tgm2-/- bone marrow flushes, bone marrow macrophages, and osteoclasts, showed a significant increase in total TG activity and TG1 activity. Factor XIII-A activity was unchanged. Aspartate proteases, such as cathepsins, are involved in the degradation of organic bone matrix and can be produced by osteoclasts. Moreover, Cathepsin D was shown in previous work to be increased in TG2-null cells and is known to activate TG1. We show that Pepstatin A, an aspartate protease inhibitor, blocks osteoclastogenesis in wild-type and Tgm2-/- cells and decreases TG1 activity in Tgm2-/- osteoclasts. Cathepsin D protein levels were unaltered in Tgm2-/-cells and its activity moderately but significantly increased. Tgm2-/- and Tgm2+/+ bone marrow macrophages and osteoclasts also expressed Cathepsin E, and Renin of the aspartate protease family, suggesting their potential involvement in this process. Our study brings further support to the observation that TGs are significant regulators of osteoclastogenesis and that the absence of TG2 can cause increased activity of other TGs, such as TG1.

Transglutaminases in fibrosis-overview and recent advances.

Transglutaminases (TGs) are a family of protein cross-linking enzymes that are capable of stiffening and insolubilizing proteins and creating protein networks, and thereby altering biological functions of proteins. Their role in fibrosis progression has been widely investigated with a focus on kidney, lung, liver, and heart where activity is triggered by various stimuli including hypoxia, inflammation, and hyperglycemia. TG2 has been considered one of the key enzymes in the pathogenesis of fibrosis mainly through transforming growth factor beta (TGF-beta) signaling and matrix cross-linking mechanisms. Although TG2 has been most widely studied in this context, the involvement of other TGs, TG1 and Factor XIII-A (FXIII-A), is beginning to emerge. This mini-review highlights the major steps taken in the TG and fibrosis research and summarizes the most recent advances and contributions of TG2, TG1, and FXIII-A to the progression of fibrosis in various animal models. Also, their mechanisms of action as well as therapeutic prospects are discussed.

Transglutaminases are oncogenic biomarkers in human cancers and therapeutic targeting of TGM2 blocks chemoresistance and macrophage infiltration in pancreatic cancer.

PURPOSE: Transglutaminases (TGs) are multifunctional enzymes exhibiting transglutaminase crosslinking, as well as atypical GTPase/ATPase and kinase activities. Here, we used an integrated comprehensive analysis to assess the genomic, transcriptomic and immunological landscapes of TGs across cancers. METHODS: Gene expression and immune cell infiltration patterns across cancers were obtained from The Cancer Genome Atlas (TCGA) database and Gene Set Enrichment Analysis (GSEA) datasets. Western blotting, immunofluorescence staining, enzyme-linked immunosorbent assays, and orthotopic xenograft models were used to validate our database-derived results. RESULTS: We found that the overall expression of TGs (designated as the TG score) is significantly upregulated in multiple cancers and related to a worse patient survival. The expression of TG family members can be regulated through multiple mechanisms at the genetic, epigenetic and transcriptional levels. The expression of transcription factors crucial for epithelial-to-mesenchymal transition (EMT) is commonly correlated with the TG score in many cancer types. Importantly, TGM2 expression displays a close connection with chemoresistance to a wide range of chemotherapeutic drugs. We found that TGM2 expression, F13A1 expression and the overall TG score were positively correlated with the infiltration of immune cells in all cancer types tested. Functional and clinical verification revealed that a higher TGM2 expression is linked with a worse patient survival, an increased IC50 value of gemcitabine, and a higher abundance of tumor-infiltrating macrophages in pancreatic cancer. Mechanistically, we found that increased C-C motif chemokine ligand 2 (CCL2) release mediated by TGM2 contributes to macrophage infiltration into the tumor microenvironment. CONCLUSIONS: Our results reveal the relevance and molecular networks of TG genes in human cancers and highlight the importance of TGM2 in pancreatic cancer, which may provide promising directions for immunotherapy and for addressing chemoresistance.

Correlations of transglutaminase 2 expression in peripheral blood mononuclear cells with relevant inflammatory factors and disease severity in patients with atopic dermatitis / 中华皮肤科杂志

Objective:To determine the expression of transglutaminase 2 (TGM2) in peripheral blood mononuclear cells (PBMCs) from patients with atopic dermatitis (AD), and to analyze its correlation with AD-related inflammatory factors and disease severity.Methods:A total of 29 AD patients and 15 healthy controls were collected from the First Affiliated Hospital of Fujian Medical University from July 2020 to January 2021. Ten milliliters of peripheral blood samples were collected from each subject, so was the clinical information, including age, gender, course of disease, eosinophil counts, basophil counts, total IgE levels, Scoring AD index (SCORAD), etc. PBMCs were isolated by density gradient centrifugation. Fluorescence-based quantitative PCR was performed to determine the mRNA expression of TGM2 and AD-related inflammatory factors (interleukin [IL]-1β, IL-4, IL-6, IL-8, IL-10, IL-13, IL-17, thymic stromal lymphopoietin [TSLP], P2RX7 [purinergic receptor P2X, ligand-gated ion channel, 7], etc.) in PBMCs from 29 AD patients and 15 healthy controls, and flow cytometry to determine TGM2 protein expression on PBMCs. Mann-Whitney U test was used to analyze differences between groups, and Spearman correlation analysis to evaluate the correlation. Results:The relative mRNA expression of TGM2 in PBMCs did not differ between the AD group and control group ( M[ Q1, Q3]: 0.509 [0.325, 0.958] vs. 0.475 [0.328, 1.051], U = 210.50, P = 0.872). Compared with the control group, the AD group showed significantly decreased IL-4 mRNA expression (0.171[0.049, 0.449] vs. 0.824 [0.397, 1.378], P < 0.001), but significantly increased mRNA expression of IL-8 and IL-13 ( P = 0.011, 0.006, respectively). Spearman correlation analysis showed that the mRNA expression level of TGM2 in PBMCs was positively correlated with the mRNA expression levels of IL-4 and P2RX7 in the AD group ( rs = 0.42, 0.40, P = 0.024, 0.034, respectively), while there were no correlations between TGM2 mRNA expression and AD severity-related indicators (all P>0.05), such as age (21[16, 29] years), course of disease (4[1,10] years), eosinophil counts (0.33[0.18, 0.65] × 10 9/L), basophil counts (0.04[0.03, 0.06] × 10 9/L], SCORAD scores (60.5[46.98, 66.13] points), and serum total IgE levels (373 [40, 1 815] IU/ml). The relative protein expression levels of TGM2 on the surface of PBMCs did not differ between the AD group and control group (54.9 [47.6, 62.8] vs. 55.55 [51.5, 60.25], U = 112.00, P = 0.922) ], and no correlations were observed between the protein expression of TGM2 on PBMCs and AD severity-related indicators in the AD group (all P > 0.05) . Conclusion:No significant differences were observed in TGM2 mRNA expression in PBMCs or TGM2 protein expression on the surface of PBMCs between the AD patients and healthy controls, and there were no correlations between the TGM2 mRNA and protein expression and AD severity.

Type 2 Transglutaminase in Coeliac Disease: A Key Player in Pathogenesis, Diagnosis and Therapy.

Type 2 transglutaminase (TG2) is the main autoantigen in coeliac disease (CD), a widespread inflammatory enteropathy caused by the ingestion of gluten-containing cereals in genetically predisposed individuals. As a consequence, serum antibodies to TG2 represent a very useful marker in CD diagnosis. However, TG2 is also an important player in CD pathogenesis, for its ability to deamidate some Gln residues of gluten peptides, which become more immunogenic in CD intestinal mucosa. Given the importance of TG2 enzymatic activities in CD, several studies have sought to discover specific and potent inhibitors that could be employed in new therapeutical approaches for CD, as alternatives to a lifelong gluten-free diet. In this review, we summarise all the aspects regarding TG2 involvement in CD, including its enzymatic reactions in pathogenesis, the role of anti-TG2 antibodies in disease management, and the exploration of recent strategies to reduce deamidation or to use transamidation to detoxify gluten.

Etiopathogenesis of dermatitis herpetiformis.

Dermatitis herpetiformis is a rare chronic, autoimmune bullous disease linked to gluten sensitivity with intense pruritus and characteristic skin eruptions. Etiopathogenesis is complex and not fully understood. It is currently considered to be a specific cutaneous manifestation of celiac disease. Genetic, environmental and immunological factors influence both conditions. Exposure to gluten is the starting point of an inflammatory cascade leading to the formation of circulating IgA antibodies against tissue transglutaminase and skin immune IgA deposition followed by skin lesions. Binding of the immune complex deposits of IgA transglutaminases and epidermal antibodies with enzymes in the papillary dermis stimulates complement activation, neutrophil influx, proinflammatory cytokine release and overproduction of matrix metalloproteinases. We have collected current knowledge of the pathogenesis of dermatitis herpetiformis.

Solid-Phase Synthesis of Selectively Mono-Fluorobenz(o)ylated Polyamines as a Basis for the Development of 18F-Labeled Radiotracers.

Polyamines are highly attractive vectors for tumor targeting, particularly with regards to the development of radiolabeled probes for imaging by positron emission (PET) and single-photon emission computed tomography (SPECT). However, the synthesis of selectively functionalized derivatives remains challenging due to the presence of multiple amino groups of similar reactivity. In this work, we established a synthetic methodology for the selective mono-fluorobenz(o)ylation of various biogenic diamines and polyamines as lead compounds for the perspective development of substrate-based radiotracers for targeting polyamine-specific membrane transporters and enzymes such as transglutaminases. For this purpose, the polyamine scaffold was constructed by solid-phase synthesis of the corresponding oxopolyamines and subsequent reduction with BH3/THF. Primary and secondary amino groups were selectively protected using Dde and Boc as protecting groups, respectively, in orientation to previously reported procedures, which enabled the selective introduction of the reporter groups. For example, N1-FBz-spermidine, N4-FBz-spermidine, N8-FBz-spermidine, and N1-FBz-spermine and N4-FBz-spermine (FBz = 4-fluorobenzoyl) were obtained in good yields by this approach. The advantages and disadvantages of this synthetic approach are discussed in detail and its suitability for radiolabeling was demonstrated for the solid-phase synthesis of N1-[18F]FBz-cadaverine.

Transitional elevation of anti-tissue transglutaminase antibodies in children with type 1 diabetes mellitus without coeliac disease / A szöveti antitranszglutamináz átmeneti emelkedése coeliakiával nem társult I-es típusú cukorbeteg gyermekekben.

Összefoglaló. Bevezetés: Az 1-es típusú diabetes mellitus és a coeliakia gyakori társulása jól ismert. Néhány tanulmány beszámol átmeneti antitranszglutamináz-emelkedésrol 1-es típusú diabeteses betegekben, akiknél az emelkedett antitestszint gluténmentes diéta bevezetése nélkül normalizálódik. Célkituzés: Kutatásunk során az átmeneti antitranszglutamináz-emelkedés gyakoriságának meghatározását tuztük ki célul. További célunk volt a coeliakia gyakoriságának megállapítása 1-es típusú diabetesszel gondozott betegeink között. Módszer: A Semmelweis Egyetem I. Gyermekgyógyászati Klinikáján 1-es típusú diabetesszel gondozott betegeket vontuk be vizsgálatunkba (238 lány, 265 fiú, medián [IR] életkor az 1-es típusú diabetes diagnózisakor: 7,83 [4,67-11] év). Vizsgáltuk a jelenség idobeli megjelenését, az emelkedés mértékét, gyakoriságát és az antitest típusát. Leíró statisztikai módszereket és khi-négyzet-próbát alkalmaztunk. Eredmények: A vizsgált populációban a coeliakia gyakorisága 12,52%. Átmeneti antitranszglutamináztiter-emelkedést 48 gyermeknél (10,9%) észleltünk. Összesen 71-szer mértünk átmeneti antitranszglutamináz-emelkedést. A gyermekek közül 34 esetben (70,83%) egyszer fordult elo emelkedést mutató antitest, a többi betegnél 2-8 alkalommal. Gyakrabban tapasztaltunk izolált IgA-típusú emelkedést, mint izolált IgG-típusút (54 vs. 5). Következtetés: Az átmeneti antitranszglutamináz-emelkedés gyakorisága magas, összevetheto a valódi coeliakiás csoporttal. Kutatásunk alátámasztja a nemzetközi ajánlást, miszerint mérsékelt mértéku antitranszglutamináz-emelkedés esetén, tünetmentes 1-es típusú diabetesszel gondozott betegben a gluténfogyasztás folytatása és az antitestszintek gyakori kontrollja javasolt. Orv Hetil. 2021; 162(48): 1924-1930. INTRODUCTION: The frequent association of type 1 diabetes mellitus with coeliac disease is well known. Development of transitional elevation of anti-tissue transglutaminase antibodies in the diagnosis of type 1 diabetes is reported in some studies. In these cases, the anti-tissue transglutaminase antibodies returned to normal without gluten-free diet. OBJECTIVE: Our aim was to assess the frequency of transitional elevation of anti-tissue transglutaminase in our type 1 diabetes patients. We aimed to investigate the prevalence of coeliac disease in patients with type 1 diabetes. METHOD: Patients with type 1 diabetes at the Ist Department of Paediatrics, Semmelweis University, were enrolled in the study (238 girls, 265 boys; the median age at the time of type 1 diabetes diagnosis was 7.83 [4.67-11] years). Descriptive statistical analysis was done and the time of appearance, extent, frequency and type of elevated anti-tissue transglutaminase antibodies were examined. RESULTS: The proportion of children with diagnosed coeliac disease was 12.52%. We detected transitional anti-tissue transglutaminase elevation in 48 cases (10.9%). Temporarily elevated antibody levels were measured 71 times. In 34 children (70.83%), the temporary elevation occured once, while in the others, antibody levels became positive 2-8 times. The elevation of the IgA antibody was more frequent than the elevation of the IgG antibody (54 vs. 5). CONCLUSION: The frequency of temporary elevated anti-tissue transglutaminase levels is considered high. Our study confirms the recommendation that in the case of moderate anti-tissue transglutaminase levels with lack of clinical symptoms, control antibody measurement is necessary with ongoing gluten consumption. Orv Hetil. 2021; 162(48): 1924-1930.

Mass Spectrometric Identification of a Novel Factor XIIIa Cross-Linking Site in Fibrinogen.

Transglutaminases are a class of enzymes that catalyze the formation of a protein:protein cross-link between a lysine and a glutamine residue. These cross-links play important roles in diverse biological processes. Analysis of cross-linking sites in target proteins is required to elucidate their molecular action on target protein function and the molecular specificity of different transglutaminase isozymes. Mass-spectrometry using settings designed for linear peptide analysis and software designed for the analysis of disulfide bridges and chemical cross-links have previously been employed to identify transglutaminase cross-linking sites in proteins. As no control peptide with which to assess and improve the mass spectrometric analysis of TG cross-linked proteins was available, we developed a method for the enzymatic synthesis of a well-defined transglutaminase cross-linked peptide pair that mimics a predicted tryptic digestion product of collagen I. We then used this model peptide to determine optimal score thresholds for correct peptide identification from y- and b-ion series of fragments produced by collision-induced dissociation. We employed these settings in an analysis of fibrinogen cross-linked by the transglutaminase Factor XIIIa. This approach resulted in identification of a novel cross-linked peptide in the gamma subunit. We discuss the difference in behavior of ions derived from different cross-linked peptide sequences and the consequent demand for a more tailored mass spectrometry approach for cross-linked peptide identification compared to that routinely used for linear peptide analysis.

Self-reported Wheat Sensitivity in Irritable Bowel Syndrome and Healthy Subjects: Prevalence of Celiac Markers and Response to Wheat-free Diet.

BACKGROUND/AIMS: Most patients with irritable bowel syndrome (IBS) report food-related aggravation of symptoms. Wheat/gluten is one of the most commonly incriminated. We studied the prevalence of self-reported wheat sensitivity in patients with IBS and in a healthy population from a region in India consuming mixed-cereal diets, correlated it with serological and human leukocyte antigen (HLA) markers of celiac disease, and evaluated the response to a wheat-free diet. METHODS: We surveyed 204 patients with IBS and 400 healthy persons for self-reported wheat sensitivity. Testing for IgA anti-tissue transglutaminase and HLA DQ2 or DQ8 was done in individuals who reported wheat sensitivity. Consenting persons with wheat sensitivity were put on wheat-free diet and monitored for symptom change. RESULTS: Twenty-three of 204 patients with IBS (11.3%) and none of the healthy subjects self-reported wheat sensitivity. Of 23 patients, 14 (60.9%) were positive for HLA DQ2 or DQ8 and none for anti-tissue transglutaminase antibody. After 6 weeks on wheat-free diet, all 19 participating patients reported clinical improvement; fewer patients had bloating, diarrhea, constipation, and easy fatigue. CONCLUSIONS: Eleven percent of patients with IBS self-reported wheat sensitivity. None of them had positive celiac serology; 60.9% were positive for HLA DQ2 and DQ8, suggesting a possible genetic basis. All of them improved symptomatically on a wheat-free diet.

Collagen crosslinking: effect on structure, mechanics and fibrosis progression.

Biophysical properties of extracellular matrix (ECM), such as matrix stiffness, viscoelasticity and matrix fibrous structure, are emerging as important factors that regulate progression of fibrosis and other chronic diseases. The biophysical properties of the ECM can be rapidly and profoundly regulated by crosslinking reactions in enzymatic or non-enzymatic manners, which further alter the cellular responses and drive disease progression. In-depth understandings of crosslinking reactions will be helpful to reveal the underlying mechanisms of fibrosis progression and put forward new therapeutic targets, whereas related reviews are still devoid. Here, we focus on the main crosslinking mechanisms that commonly exist in a plethora of chronic diseases (e.g. fibrosis, cancer, osteoarthritis) and summarize current understandings including the biochemical reaction, the effect on ECM properties, the influence on cellular behaviors, and related studies in disease model establishment. Potential pharmaceutical interventions targeting the crosslinking process and relevant clinical studies are also introduced. Limitations of pharmaceutical development may be due to the lack of systemic investigations related to the influence on crosslinking mechanism from micro to macro level, which are discussed in the last section. We also propose the unclarified questions regarding crosslinking mechanisms and potential challenges in crosslinking-targeted therapeutics development.

Dermatitis herpetiforme y enfermedad celíaca: del intestino a la piel / Dermatitis herpetiformis and celiac disease

Dermatitis herpetiformis is an autoimmune chronic blistering disease, considered a skin manifestation of celiac disease. Being both conditions multifactorial, they share some genetic traits and pathogenic mechanisms, which are responsible for the typical skin and gastrointestinal manifestations. In dermatitis herpetiformis, skin and other lesions heal after gluten-free diet and reappear shortly after its reintroduction to complete diet. Prevalence of celiac disease is 1% in the population, and approximately 13% of patients with the disease develop dermatitis herpetiformis. Diagnosis of celiac disease has progressively increased in recent decades, while clinical manifestations become more and more diverse. Given the current high frequency of skin lesions in celiac patients, in this review we update relevant aspects of the epidemiology, pathogenesis, clinical presentations, treatment and follow up of dermatitis herpetiformis, as a contribution to improve the management of both conditions.

TGFß-1 Induced Cross-Linking of the Extracellular Matrix of Primary Human Dermal Fibroblasts.

Excessive cross-linking is a major factor in the resistance to the remodelling of the extracellular matrix (ECM) during fibrotic progression. The role of TGFß signalling in impairing ECM remodelling has been demonstrated in various fibrotic models. We hypothesised that increased ECM cross-linking by TGFß contributes to skin fibrosis in Systemic Sclerosis (SSc). Proteomics was used to identify cross-linking enzymes in the ECM of primary human dermal fibroblasts, and to compare their levels following treatment with TGFß-1. A significant upregulation and enrichment of lysyl-oxidase-like 1, 2 and 4 and transglutaminase 2 were found. Western blotting confirmed the upregulation of lysyl hydroxylase 2 in the ECM. Increased transglutaminase activity in TGFß-1 treated ECM was revealed from a cell-based assay. We employed a mass spectrometry-based method to identify alterations in the ECM cross-linking pattern caused by TGFß-1. Cross-linking sites were identified in collagens I and V, fibrinogen and fibronectin. One cross-linking site in fibrinogen alpha was found only in TGFß-treated samples. In conclusion, we have mapped novel cross-links between ECM proteins and demonstrated that activation of TGFß signalling in cultured dermal fibroblasts upregulates multiple cross-linking enzymes in the ECM.

Coagulation Factor XIII Subunit A Is a Biomarker for Curative Effects and Prognosis in Malignant Solid Tumors, Especially Non-small Cell Lung Cancer.

BACKGROUND: The expression of coagulant factor XIII subunit A (FXIII-A) is significantly increased in some types of cancer cells and tumor-associated macrophages (TAMs). However, few studies on plasma FXIII-A in cancer patients have been conducted and have shown contradictory results, so the relationship of plasma FXIII-A with the progression and prognosis of malignant tumors is still unknown. This study explored the association of plasma FXIII-A with a curative effect and the prognosis of patients with malignant solid tumors. METHODS: We monitored plasma FXIII-A before and during systemic therapy and assessed its relationship with the curative effect and prognosis of malignant solid tumors, especially non-small cell lung carcinoma (NSCLC), by propensity-adjusted, multivariable logistic regression analysis and survival curve, in a prospective study of 1147 patients with different types of malignant solid tumors. The influencing factors of plasma FXIII-A were also analyzed. RESULTS: We found that D-dimer (D2) = 1 mg/L was the inflection point for the association between FXIII-A and D2: FXIII-A was significantly negatively correlated with D2 (r = -0.39, p < 0.01) and FDP (r = -0.40, p < 0.01) in D2 > 1 mg/L but uncorrelated with D2 or FDP in D2 ≤ 1 mg/L, which provided a method to find a more realistic plasma FXIII-A level. Plasma FXIII-A was positively correlated with age, platelets, lymphocytes, monocytes and carcinoembryonic antigen (CEA). It was found for the first time that plasma FXIII-A was abnormally significantly increased (FXIII-A > 150%) in post-therapy patients, especially in NSCLC and lung metastasis patients, and the incidence of FXIII-A > 150% in lung adenocarcinoma was 16 times higher than that in lung squamous carcinoma. FXIII-A > 150% proved to be an independent risk factor for disease progression in NSCLC patients (OR=5.74, 95% CI: 1.20-27.60, p = 0.029), predicting poor efficacy. The marked decrease in plasma FXIII-A (FXIII-A < 40%) was related to coagulation disorders and poor prognosis with a short survival time (median survival time of 4 months). CONCLUSIONS: Plasma FXIII-A has the potential to be a real-time biomarker with bidirectional indicator effects to assess curative effects and prognosis in malignant solid tumors, especially NSCLC.

Effect of enzyme-induced collagen crosslinking on porcine sclera.

This study aims to evaluate the effect of a new type of collagen crosslinking (CXL) mediated by microbial transglutaminases (Tgases) on sclera. Porcine eyes were divided into two groups according to the different crosslinking procedures used: the double-sided CXL group (D-CXL group) and the single-sided CXL group (S-CXL group). In the D-CXL group, 4.0 × 14.0 mm scleral strips harvested from 40 porcine eyeballs were incubated with 1 U/ml Tgases for 30 min at 37 °C. Parallel scleral strips from the same eyeball were incubated with PBS under the same conditions as the controls. In the S-CXL group, 80 whole globes were directly incubated with 1 U/ml Tgases and PBS as the controls for 30 min at 37 °C. After incubation, 4.0 × 14.0 mm scleral strips were cut from each eyeball. Biomechanical testing and light microscopy were used. In the D-CXL group, the general elastic modulus of the Tgases-treated scleral strips was 14.89 ± 6.05 MPa, and the controls was 6.72 ± 2.58 MPa, indicating an increase of 121% with Tgases treatment. In the S-CXL group, the general elastic modulus of the Tgases-treated scleral strips was 12.88 ± 4.29 MPa, and the controls was 7.00 ± 2.45 MPa, indicating an increase of 84% with Tgases treatment. In both the D-CXL and S-CXL groups, significant increases in scleral rigidity were observed compared to that of the respective controls (P < 0.05). The histology indicated increased collagen bundle density, decreased interfibrillar spaces and increased interlamellar spaces after CXL. In conclusion, scleral collagen crosslinking mediated by Tgases produced a significant increase in biomechanical strength.

Seroprevalencia poblacional de la enfermedad celiaca en zonas urbanas del Perú / Population seroprevalence of celiac disease in urban areas of Peru

RESUMEN El objetivo del estudio fue determinar la seroprevalencia de la enfermedad celiaca (EC) en zonas urbanas del Perú, utilizando una muestra de base poblacional. Se tamizó una muestra aleatoria de mujeres y varones de 18 a 29 años de 26 ciudades del Perú. Para la detección de la EC se utilizó el kit anti-transglutaminasa tisular IgA. Los resultados mayores a 20 AU/ml fueron considerados positivos. La prevalencia ponderada de la EC fue de 1,2% (IC 95%: 0,0‒2,4) y se estima que el número de personas viviendo con EC en el Perú fue de 341 783. La prevalen cia de la EC en el Perú resultó ser similar al promedio mundial.

ABSTRACT The objective of the study was to determine the seroprevalence of celiac disease (CD) in urban areas of Peru using a population-based sample. A random sample of women and men 18 to 29 years old from 26 cities in Peru was screened. An anti-tissue transglutaminase IgA kit was used for the detection of CD. Results higher than 20 AU / ml were considered positive. The weighted prevalence of celiac disease was 1.2% (CI 95%: 0.0% - 2.4%), thus the estimated number of people living with CD in Peru was 341,783. CD prevalence in Peru is similar to the world average.

From transglutaminases (TGs) to arylamine N-acetyltransferases (NATs): Insight into the role of a spatially conserved aromatic amino acid position in the active site of these two families of enzymes.

Transglutaminases (TG) and arylamine N-acetyltransferases (NAT) are important family of enzymes. Although they catalyze different reactions and have distinct structures, these two families of enzymes share a spatially conserved catalytic triad (Cys, His, Asp residues). In active TGs, a conserved Trp residue located close to the triad cysteine is crucial for catalysis through stabilization of transition states. Here, we show that in addition to sharing a similar catalytic triad with TGs, functional NAT enzymes also possess in their active site an aromatic residue (Phe, Tyr or Trp) occupying a structural position similar to the Trp residue of active TGs. More importantly, as observed in active TGs, our data indicates that in functional NAT enzymes this conserved aromatic residue is also involved in stabilization of transition states. These results thus indicate that in addition to the three triad residues, these two families of enzymes also share a spatially conserved aromatic amino acid position important for catalysis. Identification of residues involved in the stabilization of transition states is important to develop potent inhibitors. Interestingly, NAT enzymes have been shown as potential targets of clinical interest.

Transglutaminases: part I-origins, sources, and biotechnological characteristics.

The transglutaminases form a large family of intracellular and extracellular enzymes that catalyze cross-links between protein molecules. Transglutaminases crosslinking properties are widely applied to various industrial processes, to improve the firmness, viscosity, elasticity, and water-holding capacity of products in the food and pharmaceutical industries. However, the extremely high costs of obtaining transglutaminases from animal sources have prompted scientists to search for new sources of these enzymes. Therefore, research has been focused on producing transglutaminases by microorganisms, which may present wider scope of use, based on enzyme-specific characteristics. In this review, we present an overview of the literature addressing the origins, types, reactions, and general characterizations of this important enzyme family. A second review will deal with transglutaminases applications in the area of food industry, medicine, pharmaceuticals and biomaterials, as well as applications in the textile and leather industries.