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Gamma-glutamyltranspeptidase (GGT) is a novel protein involved in the induction of Helicobacter pylori-mediated apoptosis; however, the signal pathway involved in GGT-induced apoptosis remains unclear. Using DNA recombination techniques, ggt was cloned into pET117b and transformed into Escherichia coli. Recombinant GGT was purified using nickel-affinity resin and was digested by thrombin. Recombinant GGT induced apoptosis in AGS cells in a time-dependent manner, which was confirmed by TUNEL staining, the MTT assay and immunoblot analysis for caspases-9, -3, Bax, Bcl-2, Bcl-xL and cytochrome c release. Activation of caspase-3 and -9 following exposure to GGT increased in a time-dependent manner and upregulation of proapoptotic Bax and a downregulation of antiapoptotic Bcl-2 and Bcl-xL was detected. Apoptotic signals also trigger changes in mitochondria, which lead to a release of cytochrome c into the cytosolic space. The GGT-deficient mutant was not as able to induce apoptosis as the wild-type strain. These results indicate that GGT of H. pylori induces apoptosis via a mitochondria-mediated pathway.

Background TNF-related apoptosis-inducing ligand (TRAIL) is a member of the tumor necrosis factor receptor superfamily and its serum level is known to be closely associated with future cardiovascular events and prognosis of various cardiovascular diseases. We investigated whether serum TRAIL levels are associated with the severity of acute ischemic stroke and specific stroke subtype. Methods We used an enzyme-linked immunosorbent assay to measure the serum TRAIL levels of 293 patients with acute ischemic stroke within 7 days of onset. Stroke subtype was classified as large artery atherosclerosis, cardioembolism, small vessel occlusion and other determined etiology. We used National Institute of Health Stroke Scale (NIHSS) score of first hospital day and stroke volume on diffusion-weighted imaging within 7 days of stroke onset for measuring the severity of acute ischemic stroke. Results The level of serum TRAIL showed significant negative correlations with NIHSS score and stroke volume. Serum TRAIL levels significantly decreased as the tertile of NIHSS score and stroke volume increased. The relative risk of patients with serum TRAIL < 64.0 pg/mL for the presence of highest tertile of NIHSS score was significantly increased (adjusted OR [95%CI]; 7.07 [3.64–13.74]). Regarding stroke volume, the relative risk of patients with serum TRAIL < 71.5 pg/mL for the presence of highest tertile of stroke volume was also significantly increased (adjusted OR [95%CI]; 2.81 [1.61–4.92]). There are no significant differences of serum TRAIL level among stroke subtypes. Conclusions Low serum TRAIL levels were significantly associated with the acute ischemic stroke severity. This finding suggests that serum TRAIL might also have a role in acute ischemic stroke as well as other cardiovascular diseases. [ABSTRACT FROM AUTHOR]

Abstract: γ-Glutamyltranspeptidase (GGT) is a novel protein involved in the induction of Helicobacter pylori-mediated apoptosis; however, the signal pathway involved in GGT-induced apoptosis remains unclear. Using DNA recombination techniques, ggt was cloned into pET117b and transformed into Escherichia coli. Recombinant GGT was purified using nickel-affinity resin and was digested by thrombin. Recombinant GGT induced apoptosis in AGS cells in a time-dependent manner, which was confirmed by TUNEL staining, the MTT assay and immunoblot analysis for caspases-9, -3, Bax, Bcl-2, Bcl-xL and cytochrome c release. Activation of caspase-3 and -9 following exposure to GGT increased in a time-dependent manner and upregulation of proapoptotic Bax and a downregulation of antiapoptotic Bcl-2 and Bcl-xL was detected. Apoptotic signals also trigger changes in mitochondria, which lead to a release of cytochrome c into the cytosolic space. The GGT-deficient mutant was not as able to induce apoptosis as the wild-type strain. These results indicate that GGT of H. pylori induces apoptosis via a mitochondria-mediated pathway. [Copyright &y& Elsevier]