Figure 2: Importance of MRTF signalling for neovascularization in vivo.
From: MRTF-A controls vessel growth and maturation by increasing the expression of CCN1 and CCN2
(a) qRT–PCR analysis revealed an increase in MRTF-A in the rAAV.MRTF-A-transduced ischaemic hindlimb. (b) rAAV.MRTF-A induced MRTF/SRF target genes CCN1 and CCN2 in vivo. (c,d) rAAV.MRTF-A transduction increased capillary/muscle fibre ratio (c/mf), similar as the MRTF-activator Tß4. rAAV.Tß4 m, a mutant lacking the G-actin-binding domain, or co-application of Tß4 and rAAV.MRTF-shRNA had no effect (PECAM-1 staining, scale bar: 100 μm). (e,f) Functionally, rAAV.MRTF-A and -Tß4, but not rAAV.Tß4 m or rAAV.Tß4+MRTF-shRNA, transduction improved hindlimb perfusion at d3 and d7 (e). (g) After rAAV.Cre vector-induced MRTFB deletion in MRTF-A-deficient mice (Mrtf-a−/−/bflox/flox +rAAV.Cre=MRTF-A/B−/−Vi), Tß4 transduction was not capable of inducing angiogenesis, as opposed to Mrtf-a+/−/bflox/flox (=MRTF-A/B+/−)mice. (h) rAAV.Tß4-increased perfusion was abolished in MRTF-A/B−/−Vi mice. (i,j) In CCN1−/−Vi mice (=CCNflox/flox+rAAV.Cre), the increase of capillary/muscle fibre ratio was abolished (PECAM-1 staining, scale bar: 100 μm), as was the gain of hindlimb perfusion (k,l). (All error bars: mean±s.e.m., n=5, *P<0.05, **P<0.001, using ANOVA with the Student–Newman–Keul’s procedure).
