Elevated Transglutaminase 2 Activity Is Associated with Hypoxia-Induced Experimental Pulmonary Hypertension in Mice

DiRaimondo, Thomas R.; Klöck, Cornelius; Warburton, Rod R.; Herrera, Zachary; Penumatsa, Krishna; Toksoz, Deniz; Hill, Nicholas S.; Khosla, Chaitan; Fanburg, Barry L.

doi:10.1021/cb4006408

Cited by 57 publications

(106 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Our own studies have shown elevated serotonylated fibronectin in the serum of PAH patients and in animal models of pulmonary hypertension that we have linked to TG2 [17]. Moreover, the TG2 inhibitor ERW1041E mitigates pulmonary hypertension in a rodent model [18]. Furthermore, our recent findings indicate that TG2 contributes to hypoxia-induced pulmonary vascular smooth muscle cell mitogenesis (Penumatsa et al in press).…”

Section: Introductionmentioning

confidence: 89%

Tissue transglutaminase promotes serotonin-induced AKT signaling and mitogenesis in pulmonary vascular smooth muscle cells

Penumatsa¹,

Abualkhair²,

Lin³

et al. 2014

Cellular Signalling

Self Cite

View full text Add to dashboard Cite

Tissue transglutaminase 2 (TG2) is a multifunctional enzyme that cross-links proteins with monoamines such as serotonin (5-hydroxytryptamine, 5-HT) via a transglutamidation reaction, and is associated with pathophysiologic vascular responses. 5-HT is a mitogen for pulmonary artery smooth muscle cells (PASMC) that has been linked to the pulmonary vascular remodeling underlying pulmonary hypertension development. We previously reported that 5-HT-induced PASMC proliferation is inhibited by the TG2 inhibitor monodansylcadaverine (MDC); however, the mechanisms are poorly understood. In the present study we hypothesized that TG2 contributes to 5-HT-induced signaling pathways of PASMC. Pre-treatment of bovine distal PASMC with varying concentrations of the inhibitor MDC led to differential inhibition of 5-HT-stimulated AKT and ROCK activation, while p-P38 was unaffected. Concentration response studies showed significant inhibition of AKT activation at 50 μM MDC, along with inhibition of the AKT downstream targets mTOR, p-S6 Kinase and p-S6. Furthermore, TG2 depletion by siRNA led to reduced 5-HT-induced AKT activation. Immunoprecipitation studies showed that 5-HT treatment led to increased levels of serotonylated AKT and increased TG2-AKT complex formations which were inhibited by MDC. Overexpression of TG2 point mutant cDNAs in PASMC showed that the TG2 C277V transamidation mutant blunted 5-HT-induced AKT activation and 5-HT-induced PASMC mitogenesis. Finally, 5-HT-induced AKT activation was blunted in SERT genetic knock-out rat cells, but not in their wild-type counterpart. The SERT inhibitor imipramine similarly blocked AKT activation. These results indicate that TG2 contributes to 5-HT-induced distal PASMC proliferation via promotion of AKT signaling, likely via its serotonylation. Taken together, these results provide new insight into how TG2 may participate in vascular smooth muscle remodeling.

show abstract

Section: Introductionmentioning

confidence: 89%

Tissue transglutaminase promotes serotonin-induced AKT signaling and mitogenesis in pulmonary vascular smooth muscle cells

Penumatsa¹,

Abualkhair²,

Lin³

et al. 2014

Cellular Signalling

Self Cite

View full text Add to dashboard Cite

show abstract

“…During polarization, the cells were incubated with 50 M NP161 or vehicle in the absence or presence of 200 M 5-biotinamidopentylamine, which was synthesized as described previously (34). The cells were washed in PBS, fixed for 5 min in 2% paraformaldehyde, and blocked overnight with 5% bovine serum albumin in PBS, pH 7.4, at 4°C.…”

Section: Methodsmentioning

confidence: 99%

“…Next, we evaluated TG2 activity in M0 and M1 macrophages using an established assay to measure the incorporation of 5-biotinamidopentylamine (5-BP), a small molecule TG2 activity probe (7,34). TG2 activity positively correlated with TRX secretion, because 5-BP incorporation was elevated in M1 macrophages relative to M0 macrophages (Fig.…”

Section: Tg2 Activity In Macrophages Is Mediated By Endogenousmentioning

confidence: 99%

“…A single dose of recombinant TRX (500 mg/kg) was injected intravenously along with 5-BP (100 mg/kg, intraperitoneal) at various time points, as detailed under "Experimental Procedures." The mice were sacrificed 2 h after TRX administration, and 5-BP incorporation was measured in the small intestine via a fluorescence microscopy assay reported previously (7,34,37). No TG2-dependent 5-BP incorporation was detectable in control wild-type mice.…”

Section: No C35s Trx Localized With the Ecm Of Tg2mentioning

confidence: 99%

See 1 more Smart Citation

Thioredoxin-1 Selectively Activates Transglutaminase 2 in the Extracellular Matrix of the Small Intestine

Plugis

Palanski

Weng

et al. 2017

Journal of Biological Chemistry

Self Cite

View full text Add to dashboard Cite

Edited by Ruma BanerjeeTransglutaminase 2 (TG2) catalyzes transamidation or deamidation of its substrates and is ordinarily maintained in a catalytically inactive state in the intestine and other organs. Aberrant TG2 activity is thought to play a role in celiac disease, suggesting that a better understanding of TG2 regulation could help to elucidate the mechanistic basis of this malady. Structural and biochemical analysis has led to the hypothesis that extracellular TG2 activation involves reduction of an allosteric disulfide bond by thioredoxin-1 (TRX), but cellular and in vivo evidence for this proposal is lacking. To test the physiological relevance of this hypothesis, we first showed that macrophages exposed to pro-inflammatory stimuli released TRX in sufficient quantities to activate their extracellular pools of TG2. By using the C35S mutant of TRX, which formed a metastable mixed disulfide bond with TG2, we demonstrated that these proteins specifically recognized each other in the extracellular matrix of fibroblasts. When injected into mice and visualized with antibodies, we observed the C35S TRX mutant bound to endogenous TG2 as its principal protein partner in the small intestine. Control experiments showed no labeling of TG2 knock-out mice. Intravenous administration of recombinant TRX in wild-type mice, but not TG2 knock-out mice, led to a rapid rise in intestinal transglutaminase activity in a manner that could be inhibited by small molecules targeting TG2 or TRX. Our findings support the potential pathophysiological relevance of TRX in celiac disease and establish the Cys 370 -Cys 371 disulfide bond of TG2 as one of clearest examples of an allosteric disulfide bond in mammals. Transglutaminase 2 (TG2)2 is a ubiquitous member of the mammalian transglutaminase family that catalyzes transamidation or deamidation of its protein or peptide substrates. It is expressed in many cell types (1), and a considerable fraction of the expressed protein is released into the extracellular environment through an unconventional secretory mechanism whose details have not yet been elucidated (2, 3). Aberrant activity of extracellular TG2 has been implicated in several human diseases, including celiac disease, various cancers, and certain fibrotic disorders (4 -6), yet the enzyme is dormant in the extracellular matrix (ECM) of virtually all organs under normal physiological conditions (7,8). Whereas the enzymatic chemistry of TG2 has been extensively studied, our understanding of its function and regulation is still in its infancy.The post-translational regulatory mechanisms of TG2 have been reviewed elsewhere (9). Here, we focus on the redox regulation of TG2, because it is believed to be a principal mechanism for controlling the activity of extracellular TG2. It has long been known that exposure to an oxidizing environment abolishes the enzymatic activity of TG2 (10, 11). The discovery of an unusual disulfide bond (between Cys 370 and Cys 371 ) located distal to the active site of human TG2 (12) was followed by extensiv...

show abstract

“…Perhaps the most extensively evaluated are the weakly electrophilic 3-bromo-4,5-dihydroisoxazole class of inhibitors [74-81]. In vivo experiments using a prototypical inhibitor ERW1041E blocked elevated TG2 activity in pulmonary tissue in a mouse model of pulmonary hypertension [82]. In the same study, twice-daily intraperitoneal dosing of this inhibitor at 50 mg/kg was well tolerated over the course of several weeks.…”

Section: Preclinical Targetsmentioning

confidence: 99%

Therapeutic approaches for celiac disease

Plugis

Khosla

2015

Best Practice & Research Clinical Gastroenterology

Self Cite

View full text Add to dashboard Cite

Celiac disease is a common, lifelong autoimmune disorder for which dietary control is the only accepted form of therapy. A strict gluten-free diet is burdensome to patients and can be limited in efficacy, indicating there is an unmet need for novel therapeutic approaches to supplement or supplant dietary therapy. Many molecular events required for disease pathogenesis have been recently characterized and inspire most current and emerging drug-discovery efforts. Genome-wide association studies (GWAS) confirm the importance of human leukocyte antigen genes in our pathogenic model and identify a number of new risk loci in this complex disease. Here, we review the status of both emerging and potential therapeutic strategies in the context of disease pathophysiology. We conclude with a discussion of how genes identified during GWAS and follow-up studies that enhance susceptibility may offer insight into developing novel therapies.

show abstract

Elevated Transglutaminase 2 Activity Is Associated with Hypoxia-Induced Experimental Pulmonary Hypertension in Mice

Cited by 57 publications

References 46 publications

Tissue transglutaminase promotes serotonin-induced AKT signaling and mitogenesis in pulmonary vascular smooth muscle cells

Tissue transglutaminase promotes serotonin-induced AKT signaling and mitogenesis in pulmonary vascular smooth muscle cells

Thioredoxin-1 Selectively Activates Transglutaminase 2 in the Extracellular Matrix of the Small Intestine

Therapeutic approaches for celiac disease

Contact Info

Product

Resources

About