Heme Oxygenase-1 May Affect Cell Signalling via Modulation of Ganglioside Composition

Figure 6

The opposite effects of CDCA and bilirubin on regulation of GM3 synthase expression in SH-SY5Y and HepG2 cells. (a) Relative GM3 synthase (ST3GalV) mRNA expression was determined in control cells (C), after 4 h incubation with chenodeoxycholic acid (CDCA) and/or bilirubin in SH-SY5Y cells. (b) Relative GM3 synthase (ST3GalV) protein expression by Western blot was determined in control cells (C), after 4 h incubation with chenodeoxycholic acid (CDCA) and/or bilirubin in SH-SY5Y cells. (c) Relative GM3 synthase (ST3GalV) mRNA expression was determined in control cells (C), after 4 h incubation with chenodeoxycholic acid (CDCA) and/or bilirubin in HepG2 cells. (d) PKC activity was modulated by incubating SH-SY5Y cells with PKC activator (PKC⁺) or PKC inhibitor (PKC⁻) or their combination with CDCA (CDCA/PKC⁺, CDCA/PKC⁻) for 4 h. (e) PKC activation and/or inhibition was proven by determination of mRNA expression vs. control (100% line) of PKC alpha, PKC beta, and PKC epsilon in SH-SY5Y cells. Values are expressed as % of controls. C: control; PKC⁺: PKC activation by phorbol 12-myristate 13-acetate (5 μM); PKC⁻: PKC inhibition by Ro 31-0432 (5 μM); CDCA: chenodeoxycholic acid (80 μM); CDCA/bilirubin: CDCA (80 μM) + bilirubin (1 μM). vs. C; vs. CDCA.

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