Figure 6.

Changes in miR‐143:IGFBP5 interactions are associated with myoblast senescence and affected by IL‐6 levels. (A) Myoblasts isolated from the adult and old mice or human muscle were transfected with miR‐143 mimic, inhibitor (AM143) or IGFBP5 overexpression construct; cell senescence was established via SA‐β‐galactosidase staining (dark blue). Quantification of SA‐β‐galactosidase staining is shown as % of senescent cells. (B) Quantification of Western blots is shown (n = 3). (C) Representative Western blot showing the expression of p16 and phosphorylation of Ser608 of RB protein in the myoblast following transfections with miR‐143, AM143, IGFBP5 overexpression construct or siRNA and/or siRNA against p16; adult, old – mouse myoblasts; human – human myoblasts. (D) Primary myoblasts were treated with 0.1 ng mL⁻¹ IL‐6. qPCR showing decreased expression of miR‐143 and increased expression of its targets gene, Igfbp5, following IL‐6 treatment. (E) A schematic representation of the role of miR‐143:Igfbp5 interaction in the satellite cells during aging. Expression relative to Rnu‐6 (miR‐143) or β‐2‐microglobulin (Igfbp5) is shown. Error bars show SEM, * – P < 0.05 (Student's t‐test), n = 3–4.