While PMB presented weaker effect. AWRK6 against liver injury. In summary, we have found the synthetic peptide AWRK6 as a promising novel agent N6,N6-Dimethyladenosine for LPS-induced liver injury, by inhibiting cell apoptosis through MAPK signaling pathways, which might bring new strategies for the treatment of acute and chronic liver injuries. < 0.05 compared with the LPS groups. Scale bar indicates 100 m. 2.2. AWRK6 Inhibited LPS-Induced Liver Cell Apoptosis in Mice By TUNEL assay (terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling), fragmented DNA generated during apoptosis was stained with Biotin-dUTP and Streptavidin-HRP. The liver sections showed enhanced apoptotic cells in LPS-treated group and AWRK6 treatment significantly inhibited liver cell apoptosis in mice liver, which was more effective than PMB (Figure 2A,B). Further, the key regulators of apoptosis including cleaved-caspase 9, Bax and Bcl-2 were detected using western blotting. As shown in Figure 2C,D, cleaved-caspase 9 and Bax were enhanced and Bcl-2 was reduced upon LPS treatment. AWRK6 treated group showed similar levels of cleaved-caspase 9, Bax as the blank control and enhanced Bcl-2. These results demonstrated that AWRK6 administration could inhibit LPS-induced liver cell apoptosis to protect liver injury in mice model. Open in a separate window Figure 2 AWRK6 inhibited LPS-induced apoptosis in mice liver. (A) AWRK6 (10 mg/kg) treatment for 24 h reduced DNA fragmentation induced by LPS (50 mg/kg), assayed by TUNEL assay. (B) The results of TUNEL assay were analyzed by ImageJ. (C) The protein levels of cleaved-caspase 9, BAX and Bcl-2 were analyzed by western blotting. (D) The quantification of western blotting results was carried out using ImageJ. * < 0.05 compared with the LPS groups. Scale bar indicates 100 m. 2.3. AWRK6 Inhibited LPS-Induced Liver Cell Apoptosis in HepG2 Cells To gain more insight into the consequences of AWRK6 treatment on liver cell, in vitro experiments were carried out in HepG2 liver cell. HepG2 cells were treated with 40 g/mL LPS with/without AWRK6 at different concentrations. PMB at 200 g/mL was used as a positive control. The cell viabilities were Rabbit polyclonal to CD20.CD20 is a leukocyte surface antigen consisting of four transmembrane regions and cytoplasmic N- and C-termini. The cytoplasmic domain of CD20 contains multiple phosphorylation sites,leading to additional isoforms. CD20 is expressed primarily on B cells but has also been detected onboth normal and neoplastic T cells (2). CD20 functions as a calcium-permeable cation channel, andit is known to accelerate the G0 to G1 progression induced by IGF-1 (3). CD20 is activated by theIGF-1 receptor via the alpha subunits of the heterotrimeric G proteins (4). Activation of CD20significantly increases DNA synthesis and is thought to involve basic helix-loop-helix leucinezipper transcription factors (5,6) determined using MTT assay. As shown in Figure 3A, LPS (40 g/mL for 24 h) stimulation significantly reduce the dehydrogenase activity, which is directly proportional to the number of living cells. And when the LPS-treated cells were incubated with AWRK6 (20, 40, N6,N6-Dimethyladenosine 80, 100, 150 and 200 g/mL), the cell viability was recovered in a concentration dependent manner, compared with the control group. Under phase contrast microscope, the cell morphology showed no significant change upon the treatment with LPS and AWRK6 (200 g/mL), while in PMB (200 g/mL) treated group, the cells were more spread, indicating the potential toxicity of PMB (Figure 3B). By Annexin V-FITC/PI Staining, the early (Annexin V+/PI?) and late (Annexin V+/PI+) apoptotic cells were observed under fluorescence microscopy. In the results shown in Figure 3C,D, the LPS-induced apoptotic cell number was reduced after AWRK6 treatment for 24 h, which was close to the control. While PMB presented weaker effect. Also, the protein levels of cleaved-caspase 9, Bax and Bcl-2 were analyzed by western blotting. The elevated cleaved-caspase 9, Bax and repressed Bcl-2 could be reversed by AWRK6 treatment, which was consistent with the in vivo results (Figure 3E,F). These results demonstrated that AWRK6 N6,N6-Dimethyladenosine could relieve apoptosis induced by LPS in liver cells, providing a potential apoptosis inhibitor for LPS-induced liver injury. Open in a separate window Open in a separate window Figure 3 AWRK6 inhibited LPS-induced liver cell apoptosis N6,N6-Dimethyladenosine in HepG2 cells. (A) The viabilities of HepG2 liver cells treated with LPS (40 g/mL) with/without AWRK6 for 24 h, examined by MTT assay. (B) The cells treated with LPS and AWRK6 (200 g/mL) were observed under phase contrast microscope. (C) The cell apoptosis was detected by Annexin V-FITC/PI staining followed by fluorescence microscopy. (D) The apoptotic cell N6,N6-Dimethyladenosine number in the results of Annexin V-FITC/PI staining was analyzed by ImageJ. (E) The protein levels of cleaved-caspase 9, BAX and Bcl-2 were analyzed by western blotting. (F) The results of western blotting were quantified using ImageJ. Bar indicates 100 m. * < 0.05 compared with the LPS groups. 2.4. MAPKs Were Involved in the Protection of AWRK6 against Liver Injury During LPS-induced inflammatory response and cell apoptosis, MAPK (mitogen-activated protein kinases) pathways are generally activated to induce pro-apoptotic factors and active NFB pathway, which is in direct.