BACKGROUND Colon cancer is acknowledged as one of the most common malignancies worldwide,ranking third in United States regarding incidence and mortality.Notably,approximately 40%of colon cancer cases harbor oncogenic...BACKGROUND Colon cancer is acknowledged as one of the most common malignancies worldwide,ranking third in United States regarding incidence and mortality.Notably,approximately 40%of colon cancer cases harbor oncogenic KRAS mutations,resulting in the continuous activation of epidermal growth factor receptor signaling.AIM To investigate the key pathogenic genes in KRAS mutant colon cancer holds considerable importance.METHODS Weighted gene co-expression network analysis,in combination with additional bioinformatics analysis,were conducted to screen the key factors driving the progression of KRAS mutant colon cancer.Meanwhile,various in vitro experiments were also conducted to explore the biological function of transglutaminase 2(TGM2).RESULTS Integrated analysis demonstrated that TGM2 acted as an independent prognostic factor for progression-free survival.Immunohistochemical analysis on tissue microarrays revealed that TGM2 was associated with an elevated probability of perineural invasion in patients with KRAS mutant colon cancer.Additionally,biological roles of the key gene TGM2 was also assessed,suggesting that the downregulation of TGM2 attenuated the proliferation,invasion,and migration of the KRAS mutant colon cancer cell line.CONCLUSION This study underscores the potential significance of TGM2 in the progression of KRAS mutant colon cancer.This insight not only offers a theoretical foundation for therapeutic approaches but also highlights the need for additional clinical trials and fundamental research to support our preliminary findings.展开更多
Transglutaminases(TGs;E.C.2.3.2.13)are ubiquitous enzymes which catalyze post-translational modifications of proteins.TGs and TG-catalyzed post-translational modifications of proteins have been shown to be involved in...Transglutaminases(TGs;E.C.2.3.2.13)are ubiquitous enzymes which catalyze post-translational modifications of proteins.TGs and TG-catalyzed post-translational modifications of proteins have been shown to be involved in the molecular mechanisms responsible for several human diseases.In particular,TG activity has been hypothesized to also be involved also in the molecular mechanisms responsible for human neurodegenerative diseases.In support of this hypothesis,Basso et al recently demonstrated that the TG inhibition protects against oxidative stress-induced neuronal death,suggesting that multiple TG isoforms participate in oxidative stress-induced cell death and that nonselective TG isoform inhibitors will be most effective in fighting oxidative death in neurological disorders.In this commentary,we discuss the possible molecular mechanisms by which TG activity could be involved in the pathogenesis of neurological diseases,with particular reference to neurodegenerative diseases,and the possible involvement of multiple TG isoforms expressed simultaneously in the nervous system in these diseases.Moreover,therapeutic strategies based on the use of selective or nonselective TG inhibitors for the amelioration of thesymptoms of patients with neurological diseases,characterized by aberrant TG activity,are also discussed.展开更多
Transglutaminases(TGs) are a large family of related and ubiquitous enzymes that catalyze post-translational modifications of proteins.The main activity of these enzymes is the cross-linking of a glutaminyl residue of...Transglutaminases(TGs) are a large family of related and ubiquitous enzymes that catalyze post-translational modifications of proteins.The main activity of these enzymes is the cross-linking of a glutaminyl residue of a protein/peptide substrate to a lysyl residue of a protein/peptide co-substrate.In addition to lysyl residues,other second nucleophilic co-substrates may include monoamines or polyamines(to form mono-or bi-substituted/crosslinked adducts) or-OH groups(to form ester linkages) .In the absence of co-substrates,the nucleophile may be water,resulting in the net deamidation of the glutaminyl residue.The TG enzymes are also capable of catalyzing other reactions important for cell viability.The distribution and the physiological roles of TG enzymes have been widely studied in numerous cell types and tissues and their roles in several diseases have begun to be identified."Tissue" TG(TG2) ,a member of the TG family of enzymes,has definitely been shown to be involved in the molecular mechanisms responsible for a very widespread human pathology:i.e.celiac disease(CD) .TG activity has alsobeen hypothesized to be directly involved in the pathogenetic mechanisms responsible for several other human diseases,including neurodegenerative diseases,which are often associated with CD.Neurodegenerative diseases,such as Alzheimer's disease,Parkinson's disease,supranuclear palsy,Huntington's disease and other recently identified polyglutamine diseases,are characterized,in part,by aberrant cerebral TG activity and by increased cross-linked proteins in affected brains.In this review,we discuss the physio-pathological role of TG-catalyzed reactions,with particular interest in the molecular mechanisms that could involve these enzymes in the physio-pathological processes responsible for human neurodegenerative diseases.展开更多
Films were developed from the modified wheat glutens by microbial transglutamina se(MTGase, [E/S]=10u/g,15u/g and 20u/g) in order to improve physical and barri er properties of the films.Glycerol was used as a plastic...Films were developed from the modified wheat glutens by microbial transglutamina se(MTGase, [E/S]=10u/g,15u/g and 20u/g) in order to improve physical and barri er properties of the films.Glycerol was used as a plasticizer.The films prepared from the modified-glutens by MTGase show a lower elongation at break(E) and a water vapor permeability(WVP), and a higher tensile strength(TS) than the nati ve gluten films.When the modified gluten films by different concentrations of MT Gase are immersed in water at 25℃,their weight losses decreased significantly, and their water resistance increases obviously as expected, compared with the c ontrol gluten films. Moreover, an addition of glycerol as plasticizer greatly mo dified water vapor barrier and mechanical properties of the films.展开更多
Due to the recent interest in food additives that can act as triggering factors in autoimmune diseases including celiac disease(CD),the present letter to the editor expands on the microbial transglutaminase(mTG).It is...Due to the recent interest in food additives that can act as triggering factors in autoimmune diseases including celiac disease(CD),the present letter to the editor expands on the microbial transglutaminase(mTG).It is heavily consumed by a plethora of food processing industries as“glue of proteins”thus improving product’s stability,texture and shelf life.However,more and more information is accumulated lately,questioning its safety.Its cross-linked gliadin complexes are immunogenic in CD.The enzyme increases gliadin uptake,is transported in a trans-epithelial way and deposited below the enterocyte’s line,has antiphagocytic activity,enhances intestinal permeability and creates luminal resistant isopeptide bonds.No doubt that mTG is beneficial to food industries but a caveat to public health is highly recommended.展开更多
Celiac disease (CD) is a common autoimmune condition.Previously it was considered to be a rare childhood disorder,but is actually considered a relatively common condition,present at any age,which may have multiple com...Celiac disease (CD) is a common autoimmune condition.Previously it was considered to be a rare childhood disorder,but is actually considered a relatively common condition,present at any age,which may have multiple complications and manifestations.Hematological disorders of the disease are not uncommon.Among these disorders,the most frequently reported are anemias as a result of iron deficiency,often associated with folate and/or B12 deficiency.Anemias caused by hemolysis are very rarely reported in celiac patients.An 11-year-old girl with a previous uneventful medical history presented with severe hemolytic anemia.Hemolysis was Coombs negative,accompanied by inappropriate low reticulocyte count,despite exaggerated bone marrow hyperplasia of the erythroid precursors which showed normal maturation.Serology for recent infections,including EpsteinBarr virus,parvovirus B19,cytomegalovirus and mycoplasma,were all negative.Levels of serum IgA,IgG and IgM,were all within normal ranges for age.Screeningfor anti-DNA,antinuclear,antineutrophil cytoplasmic,antimicrosomal,antithyroglobulin,and antimitochondrial antibodies and lupus anticoagulants,was negative.She was also negative for human immunodeficiency virus.Conventional therapy with corticosteroids and intravenous immunoglobulin failed.CD was serendipitously discovered upon screening for anti-tissue transglutaminase autoantibodies.The disease was confirmed by biopsy of the small intestine mucosa.The patient recovered with gluten-free diet.A unique case of CD is presented.CD should be serologically screened in each patient with Coombs negative "immune"hemolytic anemia,particularly if accompanied by "reticulocytopenia".A new hemolytic mechanism and very speculative explanation for "reticulocytopenia"are discussed.展开更多
To study the effect of tTG fully phosphorothioated antisense oligodeoxynucleotides (tTG-ASDON) on tTG expression in cultured bovine trabecular meshwork cells (BTMCs) in vitro and explore a new treatment alternativ...To study the effect of tTG fully phosphorothioated antisense oligodeoxynucleotides (tTG-ASDON) on tTG expression in cultured bovine trabecular meshwork cells (BTMCs) in vitro and explore a new treatment alternative for primary open angle glaucoma (POAG), the ASDON1 and ASDON2 complementary to the protein codogram region of tTG were designed, synthesized and phosphorothioated according to the secondary structure of tTG. The ASDON1 and ASDON2 were embedded in Lipofectamine and transfected into BTMCs. The untreated group served as negative controls. The expression of tTG in the mRNA and protein level were measured by semi-quantitative RT-PCR and immunohistochemical technique-Supervision method respectively. Our results showed that both the mRNA and the protein of tTG with tTG-ASDON1 and tTCr-ASDON2 were significantly decreased as compared with that of the controls (P〈0.05). On the other hand, no significant difference was found between the ASDON1 group and the ASDON2 group. It is concluded that the expression of tTG mRNA and protein in cultured BTMC are down-regulated by tTG- ASDON. As a result, tTG-ASDON may be used for the treatment of POAG through the inhibitory effect on the expression of tTG.展开更多
This study aimed at investigating the impact of adding microbial transglutaminase (MTGase) after rennet addition on some properties of fresh soft cheese made from camel milk. MTGase was added to milk at concentration ...This study aimed at investigating the impact of adding microbial transglutaminase (MTGase) after rennet addition on some properties of fresh soft cheese made from camel milk. MTGase was added to milk at concentration of 80, 100 and 120 U/L after 20 and 30 min of renneting. The chemical composition, yield, hardness, antioxidant activity and sensory properties of cheese were estimated. Enzymatic protein crosslinking was analyzed by SDS-PAGE. Results revealed that MTGase-treated cheeses were higher in moisture and lower in protein content compared to control. In addition, the concentration of MTGase and time of addition significantly (P 0.05) impacted these parameters. Among treated cheeses, samples with 80 U of MTGase and addition time of 20 min were the highest in total solids and protein content. Adding MTGase significantly (P 0.05) increased the cheese yield, however, increased MTGase concentration at any time of addition did not improve it. The electrophoretic patterns of MTGase-cheese proteins showed a reduction in the intensity of caseins bands and the appearance of new protein fractions with high molecular weights. However, the changes in the intensity of the whey proteins bands were not sufficiently clear as caseins. The cheese hardness was significantly (P 0.05) affected by adding MTGase. Cheese containing 80 U of MTGase had the highest hardness value compared to control and other treated samples. The antioxidant activity of cheese was negatively influenced by adding the enzyme. The use of MTGase enhanced the mouthfeel, texture and overall acceptability of cheese. However, the effect of MTGase concentration and addition time was not significant (P > 0.05) on the sensory attributes. In conclusion, adding MTGase to milk at concentration of 80 U after 20 min of renneting is recommended to improve the yield, textural and some sensory properties of fresh soft cheese made from camel milk.展开更多
AIM To verify the precision and accuracy of transglutaminase antibodies(TGA)assays across Mediterranean countries.METHODS This study involved 8 referral centres for celiac disease(CD)in 7 Mediterranean countries.A cen...AIM To verify the precision and accuracy of transglutaminase antibodies(TGA)assays across Mediterranean countries.METHODS This study involved 8 referral centres for celiac disease(CD)in 7 Mediterranean countries.A central laboratory prepared 8 kits of 7 blinded and randomized serum samples,with a titrated amount of Human TGA Ig A.Each sample was analysed three times on three different days,with each centre running a total of 21tests.The results were included in a blindly coded report form,which was sent to the coordinator centre.The coordinator estimated the mean coefficient of Variation(Co Var=σ/μ),the mean accuracy(Accur=Vobserved-Vreal)and the mean percent variation(Var%=[(Vobserved-Vreal)/Vreal]×100).RESULTS The analysis showed that 79.17%of the mean variation fell between-25%and+25%of the expected value,with the accuracy and precision progressively increasing with higher titres of TGA.From values 1.25 times greater than the normal cut-off,the measurements were highly reliable.CONCLUSION TGA estimation is a crucial step for the diagnosis of CD;given its accuracy and precision,clinicians could be confident in establishing a diagnosis.展开更多
Summary: To study whether cultured bovine trabecluar meshwork cells (BTMC) are capable of expressing tTG in protein and at mRNA level, BTMC were cultured in vitro and passaged three times, then the cells were transfer...Summary: To study whether cultured bovine trabecluar meshwork cells (BTMC) are capable of expressing tTG in protein and at mRNA level, BTMC were cultured in vitro and passaged three times, then the cells were transferred onto or cultured on sterile cover or submitted to isolation of RNA with Trizol, and the expression of tTG was detected by immunohistochemical technique and reverse transcription polymerase chain reaction (RT-PCR) respectively. Our results showed that tTG immunostaining was positive in the cytoplasm and rarely in the nucleus of cultured BTMC. No immunostaining was seen in the negative control. Moreover, a single RT-PCR amplified product whose sequence and size were in accordance with our known parameters was obtained. The expression of tTG in cultured BTMC was confirmed in protein and at mRNA level. BMTC is available more readily for the investigation of the relationship between tTG and primary open-angle glaucoma.展开更多
Transglutaminases (TGases, EC 2.3.2.13) catalyse posttranslational modification of proteins by establishing ε-(γ-glutamyl) links and covalent conjugation of polyamines. In plants, the functionality of these enzymes ...Transglutaminases (TGases, EC 2.3.2.13) catalyse posttranslational modification of proteins by establishing ε-(γ-glutamyl) links and covalent conjugation of polyamines. In plants, the functionality of these enzymes is scarcely known. The maize transglutaminase gene (tgz), the only cloned plant TGase, produces major alterations in thylakoid membrane architecture when the transglutaminase (chlTGZ) protein was over-expressed in tobacco chloroplasts, significantly increasing the number of grana stacked layers. Here we demonstrate that nuclear transformation of rice plants starting from a tgz gene truncated in 17 N-terminal aas (tgzt) non altered chloroplast thylakoid structures. F3 transformed plants were analysed for TGase activity, chlTGZ presence and tgzt transcription levels. Transformed plants exhibited double the in vitro TGase activity of the non-transformed plants. Immunoblot and quantitative RT-PCR analysis results of tgzt-rice plants grown under different illumination periods revealed that chlTGZ maintains its differential expression depending on the light regime. Nevertheless, the maize protein was localised by confocal microscopy in the cell wall of transformed rice cells. TEM analyses of the transformed cells showed normal, non-altered chloroplast thylakoid structures with the maize protein preferentially located in the cell walls. The results confirmed that the tgz eliminated sequence is essential for chloroplast targeting, being its absence sufficient to the lack of protein expression in its original plastidal compartment. Interestingly, the immunolocalization of a putative endogenous rice TGase protein is also showed. These data give further information on plant TGase functionality and its relationship to photosynthetic membranes.展开更多
Background: It is important to maintain skin homeostasis for cosmetic and medical reasons. Many ceramide-related ingredients and cosmetics have been developed to improve the skin barrier function and skin hydration. S...Background: It is important to maintain skin homeostasis for cosmetic and medical reasons. Many ceramide-related ingredients and cosmetics have been developed to improve the skin barrier function and skin hydration. Similar to extracellular lipids, the cornified envelope, which is a structure formed beneath the plasma membrane, contributes to the skin barrier function as a scaffold for extracellular lipids. Therefore, in this study, we focused on transglutaminase 1 (TGM1) which is the key enzyme for formation of the cornified envelope Objective: The objectives of this study were to identify compounds that could upregulate the expression of TGM1 and evaluate their underlying action mechanisms. Methods: Expression of the transient receptor potential channel vanilloid subfamily member 4 (TRPV4) at the mRNA and protein levels was estimated by PCR and western blotting. Effects of baicalein and Salvia officinalis (SO) extract on TGM1 mRNA expression were measured by PCR. The involvement of TRPV4 in TGM1 mRNA expression was evaluated by the inhibition and silencing of TRPV4. Results: TRPV4 was expressed in both basal cell-like HaCaT cells and suprabasal cell-like HaCaT cells. Baicalein and SO extract upregulated TGM1 mRNA expression in basal cell-like HaCaT cells. However, inhibition and silencing of TRPV4 abrogated the effects of baicalein and SO extract. Conclusion: Baicalein and SO extract upregulated the expression of TGM1 mRNA via the activation of TRPV4, suggesting that it may improve the skin barrier function by enhancing cornified envelope formation.展开更多
Gluten ataxia and other central nervous system disorders could be linked to gluten enteropathy and related autoantibodies.In this narrative review,we focus on the various neuro-logical manifestations in patients with ...Gluten ataxia and other central nervous system disorders could be linked to gluten enteropathy and related autoantibodies.In this narrative review,we focus on the various neuro-logical manifestations in patients with gluten sensitivity/celiac disease,immunological and autoimmune mechanisms of ataxia in connection to gluten sensitivity and the autoantibodies that could be used as a biomarker for diagnosing and following.We focused on the anti-gliadin antibodies,antibodies to different isoforms of tissue transglutaminase(TG)(anti-TG2,3,and 6 antibodies),anti-glycine receptor antibodies,anti-glutamine acid decarboxylase antibodies,anti-deamidated gliadin peptides antibodies,etc.Most studies found a higher prevalence of these antibodies in patients with gluten sensitivity and neurological dysfunction,presented as different neurological disorders.We also discuss the role of a gluten-free diet on the clinical improvement of patients and also on imaging of these disorders.展开更多
Hemostasis is a major challenge in surgical procedures and traumas. Conventional hemostatic methods have limited efficacy and may cause additional tissue damage. In this study, we designed a novel hemostatic agent bas...Hemostasis is a major challenge in surgical procedures and traumas. Conventional hemostatic methods have limited efficacy and may cause additional tissue damage. In this study, we designed a novel hemostatic agent based on the in situ gel formation of gelatin cross-linked by a novel microbial transglutaminase(mTGase), in which the amino acid sequences differed from commercial mTGases. The new hemostatic agent showed the same biochemical crosslinking chemistry as the final stages of the blood coagulation cascade while using gelatin as a "structural" protein(rather than fibrin) and a calcium-independent mTGase as the crosslinking catalyst(rather than factor XIIIa). In rat liver hemostasis models, the hemostatic agent not only showed a similar hemostatic effect as that of SURGIFLO~(positive control), but also stronger adhesion strength and elasticity than SURGIFLO~.Therefore, this biomimetic gelatin-mTGase mix hemostatic is a novel and effective surgical sealant.展开更多
Objective To assess the effects of nuclear translocation of tissue transglutaminase (TTG) and the release of cytochrome C on hepatocyte apoptosis and to reveal the mechanism of signal transduction of early apoptosis ...Objective To assess the effects of nuclear translocation of tissue transglutaminase (TTG) and the release of cytochrome C on hepatocyte apoptosis and to reveal the mechanism of signal transduction of early apoptosis in injured hepatocytes. Methods Hepatocytes isolated from tissue transglutaminase gene knock-out mice and rats were stimulated with ethanol. Proteins from whole cell, cytoplasm and nuclei were extracted for determination of TTG activity by 14C-putrescine incorporation. Distribution of TTG throughout the entire cell, as well as just nucleus was observed under a confocal scanning microscope. The amount of cytochrome C released from mitochondria was determined by ELISA. Cell apoptosis was observed by fluorescent cytochemistry.Results TTG activity in whole cells and nuclei was significantly increased after the hepatocytes were treated with ethanol. Cytochrome C release was remarkably increased in the cells isolated from rat and wild-type mouse after treatment with ethanol but not in TTG gene knock-out mice. Cellular apoptosis appeared in hepatocytes isolated from rats and wild-type mice but not in the hepatocytes from TTG gene knock-out mice after stimulation with ethanol.Conclusions Increased TTG in hepatocytes can be translocated into the nucleus and promote release of mitochondrial cytochrome C into the cytoplasm. Passing through a series of signal pathways, hepatocyte apoptosis is induced eventually.展开更多
AIM:To develop a novel method for the rapid and efficient extraction of exosomes secreted by tumor cells.METHODS:Unlike the traditional extraction method,the supernatants of cell cultures were concentrated,and the exo...AIM:To develop a novel method for the rapid and efficient extraction of exosomes secreted by tumor cells.METHODS:Unlike the traditional extraction method,the supernatants of cell cultures were concentrated,and the exosomes were isolated promptly and effectively using a novel nanomaterial called ExoQuick.Coomassie brilliant blue staining was used for protein quantification,and the morphology of the exosomes extracted by both methods was visualized by transmis-sion electron microscopy.Exosome marker proteins were detected by Western blot analysis.Two potential hepatoma-associated proteins,tissue transglutaminase2(TGM2)and annexin A2,were analyzed.RESULTS:The exosomes separated by the new extraction assay based on the nanomaterial were discshaped,intact vesicles with lipid bilayer membranes.They were approximately 30-100 nm in diameter,which is similar to the diameter of exosomes isolated by the traditional method.The protein concentration of exosomes extracted by the new method was approximately780μg/108 cells,and therefore,it was 19 times higher than that of exosomes extracted in the traditional manner.There were differences between the total proteins of Huh-7 cells and the exosomal proteins.Typical exosome proteins,such as the transmembrane protein CD63 and heat shock protein 70,were confirmed.Two potential hepatoma-associated proteins were also identified.TGM2 was first found to exist in the exosomes of human liver cancer cells,but annexin A2 was not secreted into exosomes.CONCLUSION:The new extraction method based on the nanomaterial is quick and efficient.The cancerassociated protein TGM2 can be secreted through an exosome-mediated non-classical secretion pathway,and it may be a valuable tumor marker.展开更多
基金Supported by National Nature Science Foundation of China,No.82100195China Postdoctoral Science Foundation,No.2021M700777Medical Research Project of Foshan Municipal Health Bureau,No.20230349.
文摘BACKGROUND Colon cancer is acknowledged as one of the most common malignancies worldwide,ranking third in United States regarding incidence and mortality.Notably,approximately 40%of colon cancer cases harbor oncogenic KRAS mutations,resulting in the continuous activation of epidermal growth factor receptor signaling.AIM To investigate the key pathogenic genes in KRAS mutant colon cancer holds considerable importance.METHODS Weighted gene co-expression network analysis,in combination with additional bioinformatics analysis,were conducted to screen the key factors driving the progression of KRAS mutant colon cancer.Meanwhile,various in vitro experiments were also conducted to explore the biological function of transglutaminase 2(TGM2).RESULTS Integrated analysis demonstrated that TGM2 acted as an independent prognostic factor for progression-free survival.Immunohistochemical analysis on tissue microarrays revealed that TGM2 was associated with an elevated probability of perineural invasion in patients with KRAS mutant colon cancer.Additionally,biological roles of the key gene TGM2 was also assessed,suggesting that the downregulation of TGM2 attenuated the proliferation,invasion,and migration of the KRAS mutant colon cancer cell line.CONCLUSION This study underscores the potential significance of TGM2 in the progression of KRAS mutant colon cancer.This insight not only offers a theoretical foundation for therapeutic approaches but also highlights the need for additional clinical trials and fundamental research to support our preliminary findings.
文摘Transglutaminases(TGs;E.C.2.3.2.13)are ubiquitous enzymes which catalyze post-translational modifications of proteins.TGs and TG-catalyzed post-translational modifications of proteins have been shown to be involved in the molecular mechanisms responsible for several human diseases.In particular,TG activity has been hypothesized to also be involved also in the molecular mechanisms responsible for human neurodegenerative diseases.In support of this hypothesis,Basso et al recently demonstrated that the TG inhibition protects against oxidative stress-induced neuronal death,suggesting that multiple TG isoforms participate in oxidative stress-induced cell death and that nonselective TG isoform inhibitors will be most effective in fighting oxidative death in neurological disorders.In this commentary,we discuss the possible molecular mechanisms by which TG activity could be involved in the pathogenesis of neurological diseases,with particular reference to neurodegenerative diseases,and the possible involvement of multiple TG isoforms expressed simultaneously in the nervous system in these diseases.Moreover,therapeutic strategies based on the use of selective or nonselective TG inhibitors for the amelioration of thesymptoms of patients with neurological diseases,characterized by aberrant TG activity,are also discussed.
文摘Transglutaminases(TGs) are a large family of related and ubiquitous enzymes that catalyze post-translational modifications of proteins.The main activity of these enzymes is the cross-linking of a glutaminyl residue of a protein/peptide substrate to a lysyl residue of a protein/peptide co-substrate.In addition to lysyl residues,other second nucleophilic co-substrates may include monoamines or polyamines(to form mono-or bi-substituted/crosslinked adducts) or-OH groups(to form ester linkages) .In the absence of co-substrates,the nucleophile may be water,resulting in the net deamidation of the glutaminyl residue.The TG enzymes are also capable of catalyzing other reactions important for cell viability.The distribution and the physiological roles of TG enzymes have been widely studied in numerous cell types and tissues and their roles in several diseases have begun to be identified."Tissue" TG(TG2) ,a member of the TG family of enzymes,has definitely been shown to be involved in the molecular mechanisms responsible for a very widespread human pathology:i.e.celiac disease(CD) .TG activity has alsobeen hypothesized to be directly involved in the pathogenetic mechanisms responsible for several other human diseases,including neurodegenerative diseases,which are often associated with CD.Neurodegenerative diseases,such as Alzheimer's disease,Parkinson's disease,supranuclear palsy,Huntington's disease and other recently identified polyglutamine diseases,are characterized,in part,by aberrant cerebral TG activity and by increased cross-linked proteins in affected brains.In this review,we discuss the physio-pathological role of TG-catalyzed reactions,with particular interest in the molecular mechanisms that could involve these enzymes in the physio-pathological processes responsible for human neurodegenerative diseases.
基金Funded by the Science Technology Project of the National"TenthFive year plan"of China(No.2001BA501A04)
文摘Films were developed from the modified wheat glutens by microbial transglutamina se(MTGase, [E/S]=10u/g,15u/g and 20u/g) in order to improve physical and barri er properties of the films.Glycerol was used as a plasticizer.The films prepared from the modified-glutens by MTGase show a lower elongation at break(E) and a water vapor permeability(WVP), and a higher tensile strength(TS) than the nati ve gluten films.When the modified gluten films by different concentrations of MT Gase are immersed in water at 25℃,their weight losses decreased significantly, and their water resistance increases obviously as expected, compared with the c ontrol gluten films. Moreover, an addition of glycerol as plasticizer greatly mo dified water vapor barrier and mechanical properties of the films.
文摘Due to the recent interest in food additives that can act as triggering factors in autoimmune diseases including celiac disease(CD),the present letter to the editor expands on the microbial transglutaminase(mTG).It is heavily consumed by a plethora of food processing industries as“glue of proteins”thus improving product’s stability,texture and shelf life.However,more and more information is accumulated lately,questioning its safety.Its cross-linked gliadin complexes are immunogenic in CD.The enzyme increases gliadin uptake,is transported in a trans-epithelial way and deposited below the enterocyte’s line,has antiphagocytic activity,enhances intestinal permeability and creates luminal resistant isopeptide bonds.No doubt that mTG is beneficial to food industries but a caveat to public health is highly recommended.
文摘Celiac disease (CD) is a common autoimmune condition.Previously it was considered to be a rare childhood disorder,but is actually considered a relatively common condition,present at any age,which may have multiple complications and manifestations.Hematological disorders of the disease are not uncommon.Among these disorders,the most frequently reported are anemias as a result of iron deficiency,often associated with folate and/or B12 deficiency.Anemias caused by hemolysis are very rarely reported in celiac patients.An 11-year-old girl with a previous uneventful medical history presented with severe hemolytic anemia.Hemolysis was Coombs negative,accompanied by inappropriate low reticulocyte count,despite exaggerated bone marrow hyperplasia of the erythroid precursors which showed normal maturation.Serology for recent infections,including EpsteinBarr virus,parvovirus B19,cytomegalovirus and mycoplasma,were all negative.Levels of serum IgA,IgG and IgM,were all within normal ranges for age.Screeningfor anti-DNA,antinuclear,antineutrophil cytoplasmic,antimicrosomal,antithyroglobulin,and antimitochondrial antibodies and lupus anticoagulants,was negative.She was also negative for human immunodeficiency virus.Conventional therapy with corticosteroids and intravenous immunoglobulin failed.CD was serendipitously discovered upon screening for anti-tissue transglutaminase autoantibodies.The disease was confirmed by biopsy of the small intestine mucosa.The patient recovered with gluten-free diet.A unique case of CD is presented.CD should be serologically screened in each patient with Coombs negative "immune"hemolytic anemia,particularly if accompanied by "reticulocytopenia".A new hemolytic mechanism and very speculative explanation for "reticulocytopenia"are discussed.
文摘To study the effect of tTG fully phosphorothioated antisense oligodeoxynucleotides (tTG-ASDON) on tTG expression in cultured bovine trabecular meshwork cells (BTMCs) in vitro and explore a new treatment alternative for primary open angle glaucoma (POAG), the ASDON1 and ASDON2 complementary to the protein codogram region of tTG were designed, synthesized and phosphorothioated according to the secondary structure of tTG. The ASDON1 and ASDON2 were embedded in Lipofectamine and transfected into BTMCs. The untreated group served as negative controls. The expression of tTG in the mRNA and protein level were measured by semi-quantitative RT-PCR and immunohistochemical technique-Supervision method respectively. Our results showed that both the mRNA and the protein of tTG with tTG-ASDON1 and tTCr-ASDON2 were significantly decreased as compared with that of the controls (P〈0.05). On the other hand, no significant difference was found between the ASDON1 group and the ASDON2 group. It is concluded that the expression of tTG mRNA and protein in cultured BTMC are down-regulated by tTG- ASDON. As a result, tTG-ASDON may be used for the treatment of POAG through the inhibitory effect on the expression of tTG.
文摘This study aimed at investigating the impact of adding microbial transglutaminase (MTGase) after rennet addition on some properties of fresh soft cheese made from camel milk. MTGase was added to milk at concentration of 80, 100 and 120 U/L after 20 and 30 min of renneting. The chemical composition, yield, hardness, antioxidant activity and sensory properties of cheese were estimated. Enzymatic protein crosslinking was analyzed by SDS-PAGE. Results revealed that MTGase-treated cheeses were higher in moisture and lower in protein content compared to control. In addition, the concentration of MTGase and time of addition significantly (P 0.05) impacted these parameters. Among treated cheeses, samples with 80 U of MTGase and addition time of 20 min were the highest in total solids and protein content. Adding MTGase significantly (P 0.05) increased the cheese yield, however, increased MTGase concentration at any time of addition did not improve it. The electrophoretic patterns of MTGase-cheese proteins showed a reduction in the intensity of caseins bands and the appearance of new protein fractions with high molecular weights. However, the changes in the intensity of the whey proteins bands were not sufficiently clear as caseins. The cheese hardness was significantly (P 0.05) affected by adding MTGase. Cheese containing 80 U of MTGase had the highest hardness value compared to control and other treated samples. The antioxidant activity of cheese was negatively influenced by adding the enzyme. The use of MTGase enhanced the mouthfeel, texture and overall acceptability of cheese. However, the effect of MTGase concentration and addition time was not significant (P > 0.05) on the sensory attributes. In conclusion, adding MTGase to milk at concentration of 80 U after 20 min of renneting is recommended to improve the yield, textural and some sensory properties of fresh soft cheese made from camel milk.
基金Supported by Italian Department of Health,Direction of International AffairsEuromed action.Project:MEDICEL-Mediterranean Network for Celiac Disease-Phase II(CUP No.E61J11000450001)European Laboratory for Food Induced Disease,Federico II University,Naples
文摘AIM To verify the precision and accuracy of transglutaminase antibodies(TGA)assays across Mediterranean countries.METHODS This study involved 8 referral centres for celiac disease(CD)in 7 Mediterranean countries.A central laboratory prepared 8 kits of 7 blinded and randomized serum samples,with a titrated amount of Human TGA Ig A.Each sample was analysed three times on three different days,with each centre running a total of 21tests.The results were included in a blindly coded report form,which was sent to the coordinator centre.The coordinator estimated the mean coefficient of Variation(Co Var=σ/μ),the mean accuracy(Accur=Vobserved-Vreal)and the mean percent variation(Var%=[(Vobserved-Vreal)/Vreal]×100).RESULTS The analysis showed that 79.17%of the mean variation fell between-25%and+25%of the expected value,with the accuracy and precision progressively increasing with higher titres of TGA.From values 1.25 times greater than the normal cut-off,the measurements were highly reliable.CONCLUSION TGA estimation is a crucial step for the diagnosis of CD;given its accuracy and precision,clinicians could be confident in establishing a diagnosis.
文摘Summary: To study whether cultured bovine trabecluar meshwork cells (BTMC) are capable of expressing tTG in protein and at mRNA level, BTMC were cultured in vitro and passaged three times, then the cells were transferred onto or cultured on sterile cover or submitted to isolation of RNA with Trizol, and the expression of tTG was detected by immunohistochemical technique and reverse transcription polymerase chain reaction (RT-PCR) respectively. Our results showed that tTG immunostaining was positive in the cytoplasm and rarely in the nucleus of cultured BTMC. No immunostaining was seen in the negative control. Moreover, a single RT-PCR amplified product whose sequence and size were in accordance with our known parameters was obtained. The expression of tTG in cultured BTMC was confirmed in protein and at mRNA level. BMTC is available more readily for the investigation of the relationship between tTG and primary open-angle glaucoma.
文摘Transglutaminases (TGases, EC 2.3.2.13) catalyse posttranslational modification of proteins by establishing ε-(γ-glutamyl) links and covalent conjugation of polyamines. In plants, the functionality of these enzymes is scarcely known. The maize transglutaminase gene (tgz), the only cloned plant TGase, produces major alterations in thylakoid membrane architecture when the transglutaminase (chlTGZ) protein was over-expressed in tobacco chloroplasts, significantly increasing the number of grana stacked layers. Here we demonstrate that nuclear transformation of rice plants starting from a tgz gene truncated in 17 N-terminal aas (tgzt) non altered chloroplast thylakoid structures. F3 transformed plants were analysed for TGase activity, chlTGZ presence and tgzt transcription levels. Transformed plants exhibited double the in vitro TGase activity of the non-transformed plants. Immunoblot and quantitative RT-PCR analysis results of tgzt-rice plants grown under different illumination periods revealed that chlTGZ maintains its differential expression depending on the light regime. Nevertheless, the maize protein was localised by confocal microscopy in the cell wall of transformed rice cells. TEM analyses of the transformed cells showed normal, non-altered chloroplast thylakoid structures with the maize protein preferentially located in the cell walls. The results confirmed that the tgz eliminated sequence is essential for chloroplast targeting, being its absence sufficient to the lack of protein expression in its original plastidal compartment. Interestingly, the immunolocalization of a putative endogenous rice TGase protein is also showed. These data give further information on plant TGase functionality and its relationship to photosynthetic membranes.
文摘Background: It is important to maintain skin homeostasis for cosmetic and medical reasons. Many ceramide-related ingredients and cosmetics have been developed to improve the skin barrier function and skin hydration. Similar to extracellular lipids, the cornified envelope, which is a structure formed beneath the plasma membrane, contributes to the skin barrier function as a scaffold for extracellular lipids. Therefore, in this study, we focused on transglutaminase 1 (TGM1) which is the key enzyme for formation of the cornified envelope Objective: The objectives of this study were to identify compounds that could upregulate the expression of TGM1 and evaluate their underlying action mechanisms. Methods: Expression of the transient receptor potential channel vanilloid subfamily member 4 (TRPV4) at the mRNA and protein levels was estimated by PCR and western blotting. Effects of baicalein and Salvia officinalis (SO) extract on TGM1 mRNA expression were measured by PCR. The involvement of TRPV4 in TGM1 mRNA expression was evaluated by the inhibition and silencing of TRPV4. Results: TRPV4 was expressed in both basal cell-like HaCaT cells and suprabasal cell-like HaCaT cells. Baicalein and SO extract upregulated TGM1 mRNA expression in basal cell-like HaCaT cells. However, inhibition and silencing of TRPV4 abrogated the effects of baicalein and SO extract. Conclusion: Baicalein and SO extract upregulated the expression of TGM1 mRNA via the activation of TRPV4, suggesting that it may improve the skin barrier function by enhancing cornified envelope formation.
基金Supported by The European Union-NextGenerationEU,Through The National Recov-ery and Resilience Plan of the Republic of Bulgaria,No.BG-RRP-2.004-0008。
文摘Gluten ataxia and other central nervous system disorders could be linked to gluten enteropathy and related autoantibodies.In this narrative review,we focus on the various neuro-logical manifestations in patients with gluten sensitivity/celiac disease,immunological and autoimmune mechanisms of ataxia in connection to gluten sensitivity and the autoantibodies that could be used as a biomarker for diagnosing and following.We focused on the anti-gliadin antibodies,antibodies to different isoforms of tissue transglutaminase(TG)(anti-TG2,3,and 6 antibodies),anti-glycine receptor antibodies,anti-glutamine acid decarboxylase antibodies,anti-deamidated gliadin peptides antibodies,etc.Most studies found a higher prevalence of these antibodies in patients with gluten sensitivity and neurological dysfunction,presented as different neurological disorders.We also discuss the role of a gluten-free diet on the clinical improvement of patients and also on imaging of these disorders.
基金supported by the National Basic Research Program of China (2015CB910400, 2012CB910400)National Natural Science Foundation of China (81472788, 81272463, 81330049)
文摘Hemostasis is a major challenge in surgical procedures and traumas. Conventional hemostatic methods have limited efficacy and may cause additional tissue damage. In this study, we designed a novel hemostatic agent based on the in situ gel formation of gelatin cross-linked by a novel microbial transglutaminase(mTGase), in which the amino acid sequences differed from commercial mTGases. The new hemostatic agent showed the same biochemical crosslinking chemistry as the final stages of the blood coagulation cascade while using gelatin as a "structural" protein(rather than fibrin) and a calcium-independent mTGase as the crosslinking catalyst(rather than factor XIIIa). In rat liver hemostasis models, the hemostatic agent not only showed a similar hemostatic effect as that of SURGIFLO~(positive control), but also stronger adhesion strength and elasticity than SURGIFLO~.Therefore, this biomimetic gelatin-mTGase mix hemostatic is a novel and effective surgical sealant.
文摘Objective To assess the effects of nuclear translocation of tissue transglutaminase (TTG) and the release of cytochrome C on hepatocyte apoptosis and to reveal the mechanism of signal transduction of early apoptosis in injured hepatocytes. Methods Hepatocytes isolated from tissue transglutaminase gene knock-out mice and rats were stimulated with ethanol. Proteins from whole cell, cytoplasm and nuclei were extracted for determination of TTG activity by 14C-putrescine incorporation. Distribution of TTG throughout the entire cell, as well as just nucleus was observed under a confocal scanning microscope. The amount of cytochrome C released from mitochondria was determined by ELISA. Cell apoptosis was observed by fluorescent cytochemistry.Results TTG activity in whole cells and nuclei was significantly increased after the hepatocytes were treated with ethanol. Cytochrome C release was remarkably increased in the cells isolated from rat and wild-type mouse after treatment with ethanol but not in TTG gene knock-out mice. Cellular apoptosis appeared in hepatocytes isolated from rats and wild-type mice but not in the hepatocytes from TTG gene knock-out mice after stimulation with ethanol.Conclusions Increased TTG in hepatocytes can be translocated into the nucleus and promote release of mitochondrial cytochrome C into the cytoplasm. Passing through a series of signal pathways, hepatocyte apoptosis is induced eventually.
基金Supported by Grants from the State Key Projects for Basic Re-search,No.2011CB910703 and No.2012ZX10002-017(to Zhao XH)National High-tech R and D Program,No.2013AA041201(to Qian YM)and No.2012AA020206(to Zhao XH)+1 种基金National Natural Science Foundation of China,No.81372591 and No.81321091(to Zhao XH)the Research Foundation of the Center for Marine Medicine and Rescue of Tsinghua University and NGH(to Qian YM and Zhao XH)
文摘AIM:To develop a novel method for the rapid and efficient extraction of exosomes secreted by tumor cells.METHODS:Unlike the traditional extraction method,the supernatants of cell cultures were concentrated,and the exosomes were isolated promptly and effectively using a novel nanomaterial called ExoQuick.Coomassie brilliant blue staining was used for protein quantification,and the morphology of the exosomes extracted by both methods was visualized by transmis-sion electron microscopy.Exosome marker proteins were detected by Western blot analysis.Two potential hepatoma-associated proteins,tissue transglutaminase2(TGM2)and annexin A2,were analyzed.RESULTS:The exosomes separated by the new extraction assay based on the nanomaterial were discshaped,intact vesicles with lipid bilayer membranes.They were approximately 30-100 nm in diameter,which is similar to the diameter of exosomes isolated by the traditional method.The protein concentration of exosomes extracted by the new method was approximately780μg/108 cells,and therefore,it was 19 times higher than that of exosomes extracted in the traditional manner.There were differences between the total proteins of Huh-7 cells and the exosomal proteins.Typical exosome proteins,such as the transmembrane protein CD63 and heat shock protein 70,were confirmed.Two potential hepatoma-associated proteins were also identified.TGM2 was first found to exist in the exosomes of human liver cancer cells,but annexin A2 was not secreted into exosomes.CONCLUSION:The new extraction method based on the nanomaterial is quick and efficient.The cancerassociated protein TGM2 can be secreted through an exosome-mediated non-classical secretion pathway,and it may be a valuable tumor marker.