Our Method – Opti-Expression™

Transporter_closeupOpti-Expression™ technology– a novel transient expression approach in polarized mammalian cells

Encompassing patented methods and proprietary know-how, Opti-Expression™ technology allows rapid, robust and consistent expression of various transporter proteins in polarized mammalian cell monolayers. Compared to the use of stably transfected cell lines, this novel transient expression approach confers significant cost and time saving, unprecedented scalability and matchless flexibility in transporter assay development and set-up.

Opti-Expression™ enables one or more exogenous transporters to be over-expressed and specific endogenous transporters to be knocked down, all in polarized cell monolayers; thereby more closely mimicking in vivo biology of organ boundaries, representing a more physiologically relevant model for transporter biology study.

Opti-Expression Quintuple Transfection Model Used to Study Effects of Drugs on Creatinine Secretion

Opti-Expression™ technology was utilized to study the effect of various drugs on creatinine secretion in renal proximal tubules through the use of a novel quintuple transfection model. This collaborative study revealed that in addition to already known OCT2 and MATE1 transporters, OAT2, OCT3 and MATE2-k transporters are involved in creatinine secretion. This new finding led to development of a novel cellular model co-expressing all five transporters for modeling active creatinine secretion in the kidney.


Using the above model, Optivia scientists and collaborators, tested drugs with reported incidence of increasing serum creatinine to further understand drug effects.  Most of these drugs inhibited B>A transcellular transport of [14C]creatinine to a different extent, suggesting they are able to block active tubular secretion of creatinine in vivo. It is noteworthy that cimetidine, which has been previously demonstrated by us as a pan-inhibitor of all five transporters, was able to completely abolish creatinine transport; whereas trimethoprim, which is not an OAT2 inhibitor, only resulted in partial inhibition.

These results are in good accordance with clinical studies that higher dosage of cimetidine can completely block active creatinine secretion in proximal tubule, whereas there is no statistical difference in serum creatinine level in patients under moderate- and high-dose of trimethoprim.

To learn more about how Optivia’s Opti-Expression™ technology can benefit your drug discovery and development efforts with robust and consistent transporter proteins and unprecedented scalability and flexibility in transporter assay development please contact us.