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An abstract of the article "Overcoming Gender-Specific Barrier of AAV-Mediated Gene Therapy by Neonatal Intervention," by Akihiro Kume and colleagues is presented.

The classic form of phenylketonuria (PKU) is caused by deficiency of phenylalanine hydroxylase (PAH), a critical liver enzyme converting phenylalanine (Phe) to tyrosine. If untreated, elevated serum Phe levels predispose afflicted children to severe brain damage. The present therapy for PKU mandates strict restriction of protein intake, preferably for the lifetime. Therefore long-term curing means such as gene therapy are awaited. Among preclinical studies with a mouse model of PKU (Pahenu2 strain carrying a missense mutation in the PAH gene), vectors derived from adeno- associated virus (AAV) have given the most promising results. We and other investigators have successfully corrected hyperphenylalaninemia by portal delivery of recombinant AAV vectors. Similar to other AAV-mediated liver transduction models, however, female animals required much higher vector dose than males, and tended to lose the therapeutic effect over time. Aiming at better gene transfer to the liver, we investigated the efficacy of the self-complementary AAV system in Pahenu2. A self-complementary AAV vector (scAAV8/LP1-mPAH) was constructed by replacing the human factor IX gene of scAAV8/LP1-hFIX (a gift from Dr. JT Gray, St. Jude Research Hospital) with the murine PAH gene. For comparison, a conventional single strand AAV8 vector (AAV8/CAG-mPAH) was constructed by transferring the PAH expression cassette from AAV5/CAG-mPAH (Mochizuki S et al, Gene Therapy 11:1081, 2004). AAV type 8 capsid was chosen for packaging because of its stronger liver tropism than AAV2 and AAV5. In most cases, vectors were given to the peritoneal cavity of Pahenu2 mice of 4-5 weeks of age, because AAV8 vectors accumulate mainly in the liver regardless of the route of administration. In parallel to our previous experiment with AAV5, female PKU mice were refractory to AAV8/CAG-mPAH. While 1x1012 particles of the vector reduced blood Phe to the therapeutic level in males, no Phe reduction was obtained by injecting tenfold more AAV8/CAG-mPAH (1x1013 particles) to females. Portal injection of the same vector dose (1x1013 particles of AAV8/CAG-mPAH) was effective initially, but hyperphenylalaninemia revisited after 16 weeks of the treatment. In contrast, the self-complementary AAV vector brought about a dramatic effect. Within 2 weeks after receiving 3x1012 or 1x1013 particles of scAAV8/LP1-mPAH, blood Phe was completely normalized in the female Pahenu2 mice. The therapeutic effect has been stable up to 16 weeks (3x1012) and 30 weeks (1x1013), and the follow-up study is ongoing. Injection of 1x1012 particles of scAAV8/ LP1-mPAH had no effect, suggesting that the threshold dose lies somewhere between 1x1012 and 3x1012 particles when the vector is administered intraperitoneally. These results indicated that the efficacy of scAAV8/LP1-mPAH was about tenfold higher than AAV8/CAG-mPAH. Dissection of the mechanisms for this superior performance of scAAV8/LP1-mPAH should help further vector improvement for PKU treatment.Molecular Therapy (2006) 13, S87–S87; doi: 10.1016/j.ymthe.2006.08.252 [ABSTRACT FROM AUTHOR]

Since standard aminoglycoside treatment progressively causes hearing disturbance with hair cell degeneration, systemic use of the drugs is limited. Adeno-associated virus (AAV)-based vectors have been of great interest because they mediate stable transgene expression in a variety of postmitotic cells with minimal toxicity. In this study, we investigated the effects of regulated AAV1-mediated glial cell line–derived neurotrophic factor (GDNF) expression in the cochlea on aminoglycoside-induced damage. AAV1-based vectors encoding GDNF or vectors encoding GDNF with an rtTA2s-S2 Tet-on regulation system were directly microinjected into the rat cochleae through the round window at 5 × 1010 genome copies/body. Seven days after the virus injection, a dose of 333 mg/kg of kanamycin was subcutaneously given twice daily for 12 consecutive days. GDNF expression in the cochlea was confirmed and successfully modulated by the Tet-on system. Monitoring of the auditory brain stem response revealed an improvement of cochlear function after GDNF transduction over the frequencies tested. Damaged spiral ganglion cells and hair cells were significantly reduced by GDNF expression. Our results suggest that AAV1-mediated expression of GDNF using a regulated expression system in the cochlea is a promising strategy to protect the cochlea from aminoglycoside-induced damage.Molecular Therapy (2008); 16 3, 474–480. doi:10.1038/sj.mt.6300379 [ABSTRACT FROM AUTHOR]

An abstract of the article "Protection Against Aminoglycoside-Induced Ototoxicity by AAV Vector-Mediated GDNF Gene Transfer into the Cochlea," by Yuhe Liu and colleagues is presented.

An abstract of the article "Intramuscular Administration of AAV Vector Expressing Interleukin-10 in Dahl Salt-Sensitive Rats Prevents the Development of Hypertensive Heart Disease," by Mutsuko Sarukawa and colleagues is presented.

An abstract of the article "Effective Purification of Adeno-Associated Virus Vectors by Disposable Ion Exchange Membranes," by Takashi Okada, Mutsuko Nonaka-Sarukawa, Takayuki Ito and colleagues is presented.

An abstract of the article "Adipose Tissue Transduction Using AAV8-Based Vectors: Inadvertent Gene Transfer into Liver," by Yuan Yuan Zhang, Tsuyoshi Ogura and colleagues is presented.

An abstract of the article "Tissue Distribution of Expression Using AAV8-Based Vectors after Intramuscular Injection and Other Routes of Delivery," by Tsuyoshi Ogura, Hiroaki Mizukami and colleagues is presented.

An abstract of the article "Protection of Monocrotaline-Induced Pulmonary Hypertension by Adeno-Associated Virus Vector-Mediated Interleukin-10 Expression," by Takayuki Ito and colleagues is presented.

An abstract of the article "Type 1 Rep52 Is Superior to Authentic Rep52 for Producing Recombinant Adeno-Associated Virus Type 5 in Insect Cells," by Masashi Urabe, Takayo Nakakura, Hiroaki Mizukami, Akihiro Kume, Robert M. Kotin and Keiya Ozawa is presented.

An abstract of the article "AAV Vector-Mediated Neonatal Gene Transfer: Efficient Transgene Expression in Muscles after Intraperitoneal Cavity Vector Injection," by Tsuyoshi Ogura, Hiroaki Mizukami, Jun Mimuro, Takashi Okada, Hiromi Hamada, Akihiro Kume and Hiroyuki Yoshikawa is presented.