In vivo caveolin‐3 adenoviral gene delivery restores caveolin‐3 protein expression and caveolae in cardiac myocytes of caveolin‐3 knockout mice

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Caveolae are cholesterol, sphingolipid and caveolin enriched membrane microenvironments that have enriched expression of various signaling molecules. Caveolin‐3 (Cav‐3) knockout mice show no expression of Cav‐3 or formation of caveolae on the surface of cardiac myocytes. As such, these mice have aberrant cardiac function. We sought to determine if Cav‐3 adenoviral gene delivery to Cav‐3 knockout (KO) mice could restore expression of Cav‐3 protein and, more importantly, form caveolae on cardiac myocytes. Adenovirus encoding EGFP (Adv.EGFP) or Cav‐3 (Adv.Cav‐3) was delivered using indirect intracoronary injection in Cav‐3 KO mice. Three days after gene transfer, whole hearts were excised and the presence Cav‐3 protein was assessed. Densitometry of the immunoblot for Cav‐3 showed that Cav‐3 gene transfer resulted in restoration of Cav‐3 protein expression to 30% of wild‐type at three days. No Cav‐3 was detected in the mice injected with EGFP. Seven days after gene transfer, hearts were fixed and electron microscopy was used to assess caveolae formation on cardiac myocytes. Adv.Cav‐3 treated mice had restored caveolae formation, while no caveolae were observed in untreated knockout mice. The results indicate that intracoronary delivery results in efficient transgene expression. Furthermore, Cav‐3 is necessary and sufficient to drive the formation of caveolae in cardiac myocytes. Adv.Cav‐3 may offer a means to modulate caveolae number and cardiac signaling.