Journal: Journal of Biological Chemistry

Article Title: Leptin Stimulates Tissue Inhibitor of Metalloproteinase-1 in Human Hepatic Stellate Cells

doi: 10.1074/jbc.m308351200

Figure Lengend Snippet: FIG. 2. Time course of JAK and STAT phosphorylation by leptin. LX-2 cells were treated with leptin (75 ng/ml) for the time indicated, and immunoprecipitates of p-JAK1 and p-JAK2 (A) and p-STAT3 and p-STAT5 (B) were analyzed by Western blot, using the respective phospho- specific antibodies. The band intensities of p-JAKs and p-STATs were normalized to that of the corresponding nonphosphorylated JAKs and STATs, and values are expressed as -fold change relative to the control (0 min), which was assigned a value of 1. Lower panels are the corresponding histograms of data of three separate Western blot analyses. *, p 0.05; **, p 0.01; and ***, p 0.001 compared with the values at 0 min.

Article Snippet: Rabbit polyclonal OB-R(H300) antibody, goat polyclonal p-OB-R (Tyr-1141) antibody, rabbit polyclonal p-STAT3 (Tyr-705), p-STAT5 (Tyr-694), STAT3 (C-20), STAT5 (G-2), JAK1 (HR-185), and JAK2 (M-126) antibodies were obtained from Santa Cruz Biotechnology (Santa Cruz, CA).

Techniques: Phospho-proteomics, Western Blot, Control

Journal: Journal of Biological Chemistry

Article Title: Leptin Stimulates Tissue Inhibitor of Metalloproteinase-1 in Human Hepatic Stellate Cells

doi: 10.1074/jbc.m308351200

Figure Lengend Snippet: FIG. 3. JAK inhibitor AG 490 inhibits JAK and STAT phosphorylation and it also down-regulates TIMP-1 mRNA. LX-2 cells were treated with leptin (75 ng/ml) or AG 490 (50 M) or both for 30 min. Immunoprecipitates of p-JAK1 and p-JAK2 (A) and p-STAT3 and p-STAT5 (B) were analyzed by Western blot, using the respective phospho-specific antibodies. The intensity of p-JAK and p-STAT bands was normalized to that of corresponding nonphosphorylated JAK and STAT proteins, and values are presented as -fold change relative to the control (no leptin and AG 490), assigned a value of 1. C, LX-2 cells were treated with leptin (75 ng/ml) or AG 490 or both for 24 h, and the levels of TIMP-1 mRNA were analyzed by Northern blot. Me2SO (2.1 mM) was used as vehicle control for AG 490. The intensity of TIMP-1 mRNA bands on the blots was normalized to that of -actin, and values are presented as -fold change relative to the control (no leptin and AG 490), which was assigned a value of 1. The numbers above the blots A–C refer to the mean values of three separate analyses.

Article Snippet: Rabbit polyclonal OB-R(H300) antibody, goat polyclonal p-OB-R (Tyr-1141) antibody, rabbit polyclonal p-STAT3 (Tyr-705), p-STAT5 (Tyr-694), STAT3 (C-20), STAT5 (G-2), JAK1 (HR-185), and JAK2 (M-126) antibodies were obtained from Santa Cruz Biotechnology (Santa Cruz, CA).

Techniques: Phospho-proteomics, Western Blot, Control, Northern Blot

Journal: Journal of Biological Chemistry

Article Title: Leptin Stimulates Tissue Inhibitor of Metalloproteinase-1 in Human Hepatic Stellate Cells

doi: 10.1074/jbc.m308351200

Figure Lengend Snippet: FIG. 10. Schematic representation of the respective roles of the JAK-STAT and JAK-mediated H2O2-dependent MAPK pathways in TIMP-1 induction. Leptin triggers OB-RL signaling, leading to JAK1 and -2 phosphorylation. Activated JAK2 and (possibly JAK1) phospho- rylate Tyr-1141 of the OB-RL. The phosphorylated Tyr-1141 recruits STAT3 that, in turn, becomes phosphorylated by JAK2. STAT3 translocates to the nucleus to bind to the TIMP-1 promoter (67, 70). Activated JAK1 and -2 also induce H2O2 formation that, in turn, activates ERK1/2 and p38. ERK1/2 stimulates TIMP-1 promoter activity with enhanced TIMP-1 mRNA expression. p38 acts through a mechanism involving a stabilization of the TIMP-1 message with up-regulation of TIMP-1 expression.

Article Snippet: Rabbit polyclonal OB-R(H300) antibody, goat polyclonal p-OB-R (Tyr-1141) antibody, rabbit polyclonal p-STAT3 (Tyr-705), p-STAT5 (Tyr-694), STAT3 (C-20), STAT5 (G-2), JAK1 (HR-185), and JAK2 (M-126) antibodies were obtained from Santa Cruz Biotechnology (Santa Cruz, CA).

Techniques: Phospho-proteomics, Activity Assay, Expressing