Explore the vast range of titles available.

Host-directed therapies (HDTs) are emerging as a potential valid support in the treatment of drug-resistant tuberculosis (TB). Following our recent report indicating that genetic and pharmacological inhibition of transglutaminase 2 (TG2) restricts ( ) replication in macrophages, we aimed to investigate the potentials of the TG2 inhibitors cystamine and cysteamine as HDTs against TB. We showed that both cysteamine and cystamine restricted replication in infected macrophages when provided at equimolar concentrations and did not exert any antibacterial activity when administered directly on cultures. Interestingly, infection of differentiated THP-1 mRFP-GFP-LC3B cells followed by the determination of the autophagic intermediates pH distribution (AIPD) showed that cystamine inhibited the autophagic flux while restricting replication. Moreover, both cystamine and cysteamine had a similar antimicrobial activity in primary macrophages infected with a panel of clinical strains belonging to different phylogeographic lineages. Evaluation of cysteamine and cystamine activity in the human model of granuloma-like structures (GLS) further confirmed the ability of these drugs to restrict replication and to reduce the size of GLS. The antimicrobial activity of the TG2 inhibitors synergized with a second-line anti-TB drug as amikacin in human monocyte-derived macrophages and in the GLS model. Overall, the results of this study support the potential usefulness of the TG2-inhibitors cysteamine and cystamine as HDTs against TB.

Background Breast cancer (BC) is the most common malignant tumor among women worldwide. Tissue transglutaminase 2 ( TG2 ) has been reported as a major player across several types of cancer. However, the effects of TG2 in breast cancer are less known. Methods The expression of TG2 in patients with BC was detected by immunochemistry staining and RT-qPCR. The correlation of TG2 expression and clinicopathological factors or overall survival (OS) was analyzed by Chi-square test, Kaplan-Meier, and Cox-regression analysis. The effects of TG2 on cell proliferation and glycolysis were investigated in vivo and in vitro by gain- and loss-of-function experiments. Result Both mRNA and protein levels of TG2 were overexpressed in BC tissues and cultured cells. Clinical stage ( p  = 0.011), molecular subtype ( p <0.001) and survival status ( p <0.001) were significantly correlated with TG2 expression. Specifically, TG2 expression was positively associated with the clinical stage (r = 0.193, p  = 0.005) and OS (r = 0.230, p  = 0.001), while negatively associated with molecular subtype (r = − 0.161, p  = 0.020). Overexpressed TG2 was a prognostic factor of poor OS by Cox-regression analysis. Gain- and loss-of-function experiments indicated that cell proliferation and glycolysis were regulated by TG2 via the MEK/ERK/LDH pathway. TG2 -induced activation of the MEK/ERK/LDH pathway and glycolysis were attenuated by MEK inhibitor U0126. Conclusion TG2 is overexpressed in BC, which can serve as an independent prognostic factor for OS. TG2 promotes tumor cell proliferation and increases glycolysis associated with the activation of the MEK/ERK/LHD pathway.

Feline CKD is associated with an increase in the pro-fibrotic enzyme, transglutaminase 2 (TG2), in the kidney tubulointerstitium. Hypoxia is pivotal factor for the development of CKD, irrespective of its origin. In cats, tubulointerstitial sclerosis develops without significant glomerular involvement, similar to a rodent model of renal warm ischaemia (RWI). Sprague-Dawley rats underwent 60-min renal hilar clamping followed by right nephrectomy with/without intrarenal infusion of a transglutaminase inhibitor (TGI). Renal fibrosis was assessed by immunofluorescence of collagens after 28-days. Extracellular-TG-enzyme activity (eTGact) and extracellular-TG2 protein (eTG2) were measured in both the glomerular and the tubulointerstitial spaces. Renal Warm Ischemia (RWI) will induce fibrotic changes and activation of the transglutaminase pathway in both the tubulointerstitial and glomerular compartments, and that treatment with a transglutaminase inhibitor (TGI) will mitigate these effects. Rats subjected to RWI showed a significant elevation in tubulointerstitial collagen I (1.8-fold), III (4.3-fold), IV (5.5-fold), eTGact (2-fold) and eTG2 (1.9-fold), together with an increase in serum creatinine (2.7-fold). TG inhibition significantly reduced tubulointerstitial collagen I, III, IV, eTGact and eTG2 by 100%, 57%, 90%, 89%, and 91%, respectively, and decreased creatinine levels by 70%. However, RWI in the glomerulus showed a significant reduction in the TG pathway and collagen I and IV. Our findings support a causal link between TG2 and tubulointerstitial fibrosis in rats following RWI. In contrast, the glomerular TG-pathway was suppressed, suggesting a protective mechanism in response to RWI, which may help to explain the lack of glomerular involvement in feline CKD. This rodent model of RWI may be analogous to feline CKD, enabling extrapolation of findings from rodent RWI models to understand renal insult in cats.

As a promising cell therapy, neural crest-derived ectoderm mesenchymal stem cells (EMSCs) secrete high amounts of extracellular matrix (ECM) and neurotrophic factors, promoting neural stem cell (NSC) differentiation into neuronal lineages and aiding tissue regeneration. Additionally, the forced overexpression of secreted proteins can increase the therapeutic efficacy of the secretome. Tissue transglutaminase (TG2) is a ubiquitously expressed member of the transglutaminase family of calcium-dependent crosslinking enzymes, which can stabilize the ECM, inducing smart or living biomaterial to stimulate differentiation and enhance the neurogenesis of NSCs. In this study, we examined the neuronal differentiation of NSCs induced by TG2 gene-modified EMSCs (TG2-EMSCs) in a co-culture model directly. Two weeks after initiating differentiation, levels of the neuronal markers, tubulin beta 3 class III and growth-associated protein 43, were higher in NSCs in the TG2-EMSC co-culture group and those of the astrocytic marker glial fibrillary acidic protein were lower, compared with the control group. These results were confirmed by immunofluorescence, and laminin, fibronectin and sonic hedgehog (Shh) contributed to this effect. The results of western blot analysis and the enzyme-linked immunoassay showed that after TG2-EMSCs were co-cultured for 2 weeks, they expressed much higher levels of Shh than the control group. Moreover, the sustained release of Shh was observed in the TG2-EMSC co-culture group. Overall, our findings indicate that EMSCs can induce the differentiation of NSCs, of which TG2-EMSCs can promote the differentiation of NSCs compared with EMSCs.

This paper investigates the ability of our selective small molecule TG2 inhibitor 1-155 in reducing fibrosis in a bleomycin-induced pulmonary fibrosis mouse model. Formulated as a fine stable suspension, 1-155 was delivered intranasally (IN) at 3 mg/kg via IN delivery once daily. It significantly inhibited collagen deposition in the lungs in the bleomycin-challenged mice. Compared to its vehicle control treatment, a significant reduction in a key myofibroblast marker α smooth muscle actin and TG2 was also detected in the 1-155-treated animals. Most importantly, 1-155 treatment significantly improved several key lung function parameters, such as cord compliance, vital capacity, and dynamic compliance, which are comparable to that found for the positive control nintedanib at a much higher dosage of 60 mg/kg twice daily via oral delivery. The 1-155-treated mice showed a trend in improvement of average body weight. For the first time, our study demonstrates the effectiveness of a selective small molecule TG2 inhibitor in reducing pulmonary fibrosis in a pre-clinical model. Importantly, we were able to correlate this effect of 1-155 with the improvement of animal lung function showing the potential of the use of TG2 inhibitors as a therapeutic treatment for fibrotic lung conditions like IPF.

Transglutaminase 2 (TG2, a.k.a. tissue transglutaminase) belongs to a family of transglutaminase enzymes that stabilize proteins by affecting covalent crosslinking via formation of amide bonds. Cell surface TG2 is directly involved as an adhesive receptor in cell–extracellular matrix (ECM) interactions. Here, we show that TG2 activity is elevated in glioblastomas compared with non-neoplastic brain. Immunofluorescent studies showed increased staining of fibronectin colocalized with TG2 in the ECM in glioblastomas. In addition, small clusters of invading human glioblastoma cells present in non-neoplastic brain parenchyma secrete high levels of TG2 and fibronectin that distinguish them from normal brain stroma. Downregulation of TG2 in U87MG glioblastoma cells with RNAi demonstrated decreased assembly of fibronectin in the ECM. Treatment with KCC009 blocked the remodeling of fibronectin in the ECM in glioblastomas in both in vitro and in vivo studies. KCC009 treatment in mice harboring orthotopic glioblastomas (DBT-FG) sensitized the tumors to N,N ′-bis(2-chloroethyl)- N -nitrosourea chemotherapy, as measured by reduced bioluminescence, increased apoptosis and prolonged survival. The ability of KCC009 to interfere with the permissive remodeling of fibronectin in the ECM in glioblastomas suggests a novel target to enhance sensitivity to chemotherapy directed not only at the tumor mass, but also invading glioblastoma cells.

Background: IgA class serum autoantibodies against type 2 (tissue) transglutaminase (TG2) bind to both intestinal and extraintestinal normal tissue sections in vitro, eliciting endomysial, reticulin, and jejunal antibody reactions. It is not known whether similar binding also occurs in coeliac patients in vivo, and may thereby contribute to disease manifestations. Aims: To investigate intestinal and extraintestinal coeliac tissues for the presence of in vivo bound TG2 specific IgA and its relation to small intestinal mucosal atrophy. Patients: We investigated jejunal samples with normal villous morphology from 10 patients with developing coeliac disease who subsequently progressed to a flat lesion, from 11 patients with dermatitis herpetiformis, and from 12 non-coeliac controls. Six extrajejunal biopsy samples (liver, lymph node, muscle, appendix), obtained based on independent clinical indications from patients with active coeliac disease, were also studied. Methods: Double colour immunofluorescent studies for in situ IgA, TG2, and laminin were performed. IgA was eluted from tissue sections and tested for TG2 specificity by enzyme linked immunosorbent assay and indirect immunofluorescence. Results: IgA (in one IgA deficient case IgG) deposition on extracellularly located TG2 was detected in jejunal and extrajejunal specimens of all coeliac patients, and also in seven of 11 dermatitis herpetiformis patients, of whom two had no circulating endomysial antibodies. IgA eluted from extraintestinal coeliac tissues was targeted against TG2. Conclusions: Coeliac IgA targets jejunal TG2 early in disease development even when endomysial antibodies are not present in the circulation. Extraintestinal target sites of coeliac IgA further indicate that humoral immunity may have a pathogenetic role.

The long non-coding RNAs (lncRNAs) are matter of intense investigation as potential regulators of gene expression. In the case of the transglutaminase 2 gene ( TGM2 ) the databases of genome sequence indicate location of a lncRNA (LOC107987281) within the first intron. This lncRNA is 1000 bp long, arises from 2 exons and starts few nucleotides 3′ of the first splicing site of translated TGM2 . We have analysed correlations between expression of LOC107987281 lncRNA and TGM2 mRNA by real-time PCR in K562 cell line untreated or treated with the anticancer drugs TPA (12- O -tetradecanoylphorbol-13-acetate), Docetaxel and Doxorubicin. In the treated cells the lncRNA increase follows the trend of TGM2 transcript. To validate this finding we used HumanExon1_0ST Affymetrix; chip data were background-adjusted, quantile-normalized and summarized using robust multi-array average analysis implemented in the R package. The probesets recognize sequences inside each exon, near intronic splicing sites and others located in the untranslated regions of TGM2 gene. The analysis of total RNA samples in GEO datasets from K562, HL-60, THP-1 and U937 cell lines, untreated or treated with TPA in replicated experiments confirmed our earlier results. These demonstrate correlation between LOC107987281 and TGM2 mRNA in the cell lines (K562, HL60 and THP-1) where increased levels of TGM2 mRNA are produced. Additional array study on 358 samples of several normal and paired tumor tissues leads to the same conclusions, indicating a correlation between full-length TGM2 mRNA and LOC107987281 lncRNA in relation to the development of several tumors.

The multifunctional protein Transglutaminase type 2, is associated with cancer epithelial mesenchymal transition, invasiveness, stemness and drugs resistance. Several variant isoforms and non-coding RNAs are present in cancer and this report explored the expression of these transcripts of the TGM2 gene in cancer cell lines after induction with all-trans retinoic acid. The expression of truncated variants along with two long non-coding RNAs, was demonstrated. One of these is coded from the first intron and the Last Exon Variant is constituted by a sequence corresponding to the last three exons and the 3′UTR. Analysis of ChIP-seq data, from ENCODE project, highlighted factors interacting with intronic sequences, which could interfere with the progression of RNApol II at checkpoints, during the elongation process. Some relevant transcription factors, bound in an ATRA-dependent way, were found by RNA immunoprecipitation, notably GATA3 mainly enriched to Last Exon Variant non-coding RNA. The involvement of NMD in the regulation of the ratio among these transcripts was observed, as the prevalent recovering of Last Exon Variant to phUPF1-complexes, with decrease of the binding towards other selective targets. This study contributes to identify molecular mechanisms regulating the ratio among the variants and improves the knowledge about regulatory roles of the non-coding RNAs of the TGM2 gene.

Chemical modifications of histones can mediate diverse DNA-templated processes, including gene transcription 1 – 3 . Here we provide evidence for a class of histone post-translational modification, serotonylation of glutamine, which occurs at position 5 (Q5ser) on histone H3 in organisms that produce serotonin (also known as 5-hydroxytryptamine (5-HT)). We demonstrate that tissue transglutaminase 2 can serotonylate histone H3 tri-methylated lysine 4 (H3K4me3)-marked nucleosomes, resulting in the presence of combinatorial H3K4me3Q5ser in vivo. H3K4me3Q5ser displays a ubiquitous pattern of tissue expression in mammals, with enrichment observed in brain and gut, two organ systems responsible for the bulk of 5-HT production. Genome-wide analyses of human serotonergic neurons, developing mouse brain and cultured serotonergic cells indicate that H3K4me3Q5ser nucleosomes are enriched in euchromatin, are sensitive to cellular differentiation and correlate with permissive gene expression, phenomena that are linked to the potentiation of TFIID 4 – 6 interactions with H3K4me3. Cells that ectopically express a H3 mutant that cannot be serotonylated display significantly altered expression of H3K4me3Q5ser-target loci, which leads to deficits in differentiation. Taken together, these data identify a direct role for 5-HT, independent from its contributions to neurotransmission and cellular signalling, in the mediation of permissive gene expression. In serotonin-rich tissues, tissue transglutaminase 2 is able to attach serotonin to a glutamine residue in histone H3; this modification mediates permissive gene expression in these tissues.