Redox-Sensing Release of Human Thioredoxin from T Lymphocytes with Negative Feedback Loops

Abstract

Thioredoxin (TRX) is released from various types of mammalian cells despite no typical secretory signal sequence. We show here that a redox-active site in TRX is essential for its release from T lymphocytes in response to H2O2 and extracellular TRX regulates its own H2O2-induced release. Human T cell leukemia virus type I-transformed T lymphocytes constitutively release a large amount of TRX. The level of TRX release is augmented upon the addition of H2O2, but suppressed upon the addition of N-acetylcysteine. In the culture supernatant of a Jurkat transfectant expressing the tagged TRX-wild type (WT), the tagged TRX protein is rapidly released at 1 h and kept at a constant level until 6 h after the addition of H2O2. In contrast, another type of transfectant expressing the tagged TRX mutant (C32S/C35S; CS) fails to release the protein. H2O2-induced release of TRX from the transfectant is inhibited by the presence of rTRX-WT in a dose-dependent manner. Preincubation of the transfectant with rTRX-WT for 1 h at 37°C, but not 0°C, results in a significant suppression of the TRX release, reactive oxygen species, and caspase-3 activity induced by H2O2, respectively. Confocal microscopy and Western blot analysis show that extracellular rTRX-WT added to the culture does not obviously enter T lymphocytes until 24 h. These results collectively suggest that the oxidative stress-induced TRX release from T lymphocytes depends on a redox-sensitive event and may be regulated by negative feedback loops using reactive oxygen species-mediated signal transductions.

Cytoprotective Effects of Geranylgeranylacetone against Retinal Photooxidative Damage

“…Together, our results strongly suggest that Trx is a neurotrophic factor released from RPE cells that plays a crucial role in maintaining photoreceptor cell integrity against photooxidative insults. Although the precise mechanism in leaderless release of Trx from cells is currently unknown, the redox status of tissues or cells is deeply involved in the mechanism (Kondo et al, 2004).…”

“…The DNA fragments encoding human Trx (Kondo et al, 2004) were amplified by PCR and inserted between the BglII and the XbaI sites of the pEGFP-C1 vector (Clontech, Palo Alto, CA). The K-1034 cells were transfected with human Trx-pEGFP-C1 vector using Fu-GENE 6 (Roche) following the instructions of the manufacturer.…”

Redox regulation of mast cell histamine release in thioredoxin-1 (TRX) transgenic mice

“…Intracellular ROS was measured according to the methods described previously [21]. Briefly, BMMC were sensitized with anti-DNP IgE overnight, and stimulated with DNP-BSA for 30 min.…”

Protective effects of oral administration of yeast thioredoxin against gastric mucosal injury

“…We infer that yeast TRX affects the gastric cells mainly from the extracellular side in this study. In the previous report, recombinant human TRX was observed to enter into ATL2 cells gradually over 24 h. [30][31][32] We show that yeast TRX is digested within only several hours (Fig. 1), and thus it is unlikely that large fraction of active yeast TRX without denaturation enters the gastric cells.…”