Use of ultrasound to enhance nonviral lung gene transfer in vivo

Abstract

We have assessed if high-frequency ultrasound (US) can enhance nonviral gene transfer to the mouse lung. Cationic lipid GL67/pDNA, polyethylenimine (PEI)/pDNA and naked plasmid DNA (pDNA) were delivered via intranasal instillation, mixed with Optison microbubbles, and the animals were then exposed to 1 MHz US. Addition of Optison alone significantly reduced the transfection efficiency of all three gene transfer agents. US exposure did not increase GL67/ pDNA or PEI/pDNA gene transfer compared to Optisontreated animals. However, it increased naked pDNA transfection efficiency by approximately 15-fold compared to Optison-treated animals, suggesting that despite ultrasound being attenuated by air in the lung, sufficient energy penetrates the tissue to increase gene transfer. US-induced lung haemorrhage, assessed histologically, increased with prolonged US exposure. The left lung was more affected than the right and this was mirrored by a lesser increase in naked pDNA gene transfer, in the left lung. The positive effect of US was dependent on Optison, as in its absence US did not increase naked pDNA transfection efficiency. We have thus established proof of principle that US can increase nonviral gene transfer, in the air-filled murine lung.

Nerve growth factor delivery by ultrasound-mediated nanobubble destruction as a treatment for acute spinal cord injury in rats

“…17,18 To date, UTMD has been successfully used for gene transfection in diseases of the heart, lung, brain, uterus, pancreas, kidneys, retina, skin, and testes. [19][20][21][22][23][24][25][26][27] To the best of our knowledge, very few studies have investigated the use of US-mediated gene therapy for SCI. Thus, it is still unknown whether USmediated gene transfection represents an effective treatment strategy for SCI.…”

Secreted Gaussia luciferase as a sensitive reporter gene for in vivo and ex vivo studies of airway gene transfer

“…For administration of the gene transfer agent by nasal "sniffing" animals were anaesthetized with isoflurane and 100 μl of lipid:pDNA complexes containing 80 μg of pDNA were administered to the nostrils and "sniffed" into the lungs as previously described [36]. At indicated time-points after instillation mice were culled.…”

Low-frequency ultrasound increases non-viral gene transfer to the mouse lung

“…For this purpose, animals were instilled with a mixture of naked pDNA (100 mg/100 ml) and Optison (1:1, v/v) and sonoporated as above. As shown previously [12] addition of Optison reduced naked pDNA gene transfer by more than one log. Exposure to low-frequency US at 0.1 MPa significantly increased gene expression approximately 4 fold compared with the pDNA þ Optison control group (P , 0.05, n ¼ 7-8 animals/group) (Fig.…”

“…Furthermore, physical methods such as magnetofection [9] and sonoporation [10,11], have recently been applied to enhance gene transfer of both non-viral and viral vectors in several organs. We have shown that sonoporation using 1 MHz ultrasound (US) can increase naked plasmid DNA ( pDNA) transfection efficiency in the mouse lung [12]. However, this effect was dependent on the addition of Optison, an US contrast agent that thought to enhance US-mediated gene transfer by lowering the cavitation threshold [13].…”