Journal: Acta Pharmaceutica Sinica. B
Article Title: Dual alarmin-receptor-specific targeting peptide systems for treatment of sepsis
doi: 10.1016/j.apsb.2024.08.015
Figure Lengend Snippet: Mapping of the TLR4/MD2/RAGE-interacting motifs of HMGB1 or PTX3. (A, B) Schematic diagram of the domain of HMGB1 (A) and PTX3 (B) (top). GST-tagged truncates covering TLR4-, RAGE-, or MD2-binding domain of HMGB1 or PTX3 were constructed. Bottom panel (A, B) depicts GST-pull down of the indicated tagged receptors (HA-TLR4, Myc-RAGE, and His-MD2) with transiently expressed GST-tagged truncates. HEK293T cells transfected with the GST-tagged constructs in combination with HA-TLR4, Myc-RAGE or His-MD2 are indicated followed by GST-pull down. Representative western blots of WCLs and eluates after GST-pull down are shown, using GAPDH as a loading control in WCLs. Based on pulldown binding results, TLR4-, MD2-, and RAGE-targeted peptides were constructed and designated as H-T, H-R, P-T, or P-M peptides (indicated in panels A, B). (C) BMDMs were incubated with H-T, H-R, P-T, or P-M peptide for the indicated concentrations for 48 h, and then cell viability was measured with cell viability assay. Data shown are the means ± SD of three experiments (D) Cell-free immunoprecipitation assay using H-T, H-R, P-T, or P-M peptides. Mix 5 μg of alarmin protein (rHMGB1 or rPTX3) with 5 μg of each indicated tagged receptors protein (HA-TLR4, Myc-RAGE, and His-MD2), and mix as indicated to confirm the competitive inhibition effect of peptides was treated for 4 h. They were immunoprecipitated with α Flag for 2 h, separated by SDS-PAGE, and evaluated by immunoblotting. (E) Competition between rHMGB1 (top) or PTX3 (bottom) and the constructed peptides for their respective receptors. After treatment with rHMGB1 (top) or PTX3 (bottom) (10 μg/mL, 3 h) together with increasing amounts of the indicated peptides, BMDMs were used for immunoprecipitation (IP) with α TLR4 or α RAGE and IB with indicated antibodies. (F) Decrease of LPS-induced cytokine production by H-T, P-T, or P-M peptide and rHMGB1-induced cytokine production by H-R peptide. TNF- α , IL-6, IL-12p40, and IL-10 levels in the supernatant of LPS (100 ng/mL, 18 h) together with increasing amounts of the indicated peptides-treated BMDMs were determined by ELISA. The data shown represent at least three independent experiments ( n ≥ 3), bars denote mean ± SEM (∗∗∗ P < 0.001, ∗∗∗∗ P < 0.001), and significance was measured by two-way ANOVA. n.s = not significant.
Article Snippet: Flag-HMGB1 (MG50913-CF), Flag-PTX3 (HF12082-CF), HA-TLR4 (MG50657-NY), Myc-RAGE (MG50489-CM), and His-MD2 (MG51098-NH) plasmids were purchased from Sino Biological (Beijing, China).
Techniques: Binding Assay, Construct, Transfection, Western Blot, Control, Incubation, Viability Assay, Immunoprecipitation, Inhibition, SDS Page, Enzyme-linked Immunosorbent Assay