The level declined from 3 to 12 h, but the level in the LPS group significantly increased compared to the vehicle group (Fig. 2A). While the TNF-α mRNA expression level derived from blood (including leucocytes) in the LPS group also significantly increased from 0.5 h to 9 h compared
CB-839 mouse with the vehicle or LPS + Cap groups (Fig. 2A). This difference may be due to the release of stored membrane-bound TNF-α (mTNF) from macrophages 1 h after LPS stimulation . Following LPS stimulation (in inflammation), TNF-α is primarily expressed as a 26 kDa type II transmembrane protein, mTNF and is subsequently cleaved by the metalloproteinase-disintegrin TNF-α converting enzyme (TACE, also known as ADAM-17) into the secreted 17 kDa monopeptide TNF-α (sTNF) ,  and . Similarly, TACE, a member
of the ADAM family of zinc metalloproteinases, modulates the generation of sTNF-R1 and -R2 by proteolytically cleaving the TNF-R1 and -R2 ectodomains, respectively . Following a single LPS stimulation, the circulating sTNF level in the LPS group significantly and continuously increased from 3 to 12 h compared to the vehicle group. At 1 h buy GW-572016 after LPS stimulation the circulating sTNF was considered to be derived from mTNF. From 3 h onwards after LPS stimulation, the circulating sTNF level was considered to be derived from TNF-α mRNA induced by LPS. While both sTNF-R1 and -R2 mRNA levels were not differences among vehicle, LPS, and LPS + Cap groups from 0.5 h to 12 h after LPS stimulation. Furthermore, the circulating sTNF-R2 level was approximately 10-fold that those of sTNF-R1 in this study, similar to these levels of carbon tetrachloride-induced liver injury rats . TNF-R1 has been reported to bind to sTNF more frequently than TNF-R2 ; therefore, we assumed that binding with TNF-α after LPS stimulation neutralized TNF-R1, resulting in decreased circulation of both sTNF and sTNF-R1. Regarding the effects of Cap on sTNF, the sTNF level in the LPS + Cap group was significantly depressed by Cap 1 h after LPS stimulation
compared to the LPS group (Fig. 1A). Cap, therefore, has the potential to depress the production of sTNF via membrane stability. Furthermore, Cap significantly depressed TNF-α mRNA from 0.5 h until 9 h (Fig. 2A). Cap was assumed to depress the increase in TNF-α mRNA in LPS-treated mice. The above-mentioned results show that Cap has the potential to suppress TNF-α production following LPS-stimulation  and . Our results assume the following two mechanisms for the anti-TNF-α effect of Cap: firstly, Cap exerts a release-inhibiting effect on circulating sTNF from macrophages in the early phase of septicemia; secondly, Cap interferes with TNF-α mRNA transcription. Since Cap inhibits the initial increase in circulating sTNF, it is considered a potent treatment option for TNF-α-related diseases, such as septicemia.