| Purpose: Cardiovascular gene therapy is a sophisticated approach, thanks to the safety of
vectors, stable transgene expression, delivery method, and different layers of the heart. To
date, numerous expression vectors have been introduced in biotechnology and biopharmacy
industries in relation to genetic manipulation. Despite the rapid growth of these modalities,
they must be intelligently designed, addressing the cardiac-specific transgene expression
and less side effects. Herein, we conducted a pilot project aiming to design a cardiacspecific hypoxia-inducible expression cassette.
Methods: We explored a new approach to design an expression cassette containing cardiac
specific enhancer, hypoxia response elements (HRE), cardiac specific promoter, internal
ribosome entry site (IRES), and beta globin poly A sequence to elicit specific and inducible
expression of the gene of interest. Enhanced green fluorescent protein (eGFP) was subcloned by BglII and NotI into the cassette. The specificity and inducible expression of the
cassette was determined in both mouse myoblast C2C12 and mammary glandular tumor
4T1 as ‘twin’ cells. eGFP expression was evaluated by immunofluorescence microscope
and flow cytometry at 520 nm emission peak.
Results: Our data revealed that the designed expression cassette provided tissue specific
and hypoxia inducible (O2<1%) transgene expression.
Conclusion: It is suggested that cardiac-specific enhancer combined with cardiac-specific
promoter are efficient for myoblast specific gene expression. As well, this is for the first time
that HRE are derived from three well known hypoxia-regulated promoters. Therefore, there is
no longer need to overlap PCR process for one repeated sequence just in one promoter. |