Press Release
Development of a safe liver sinusoidal wall coating agent tosignificantly increase the efficacy of gene therapy drugs
Controlling the clearance of gene therapy drugs at the liver sinusoidal wallNew technology to improve the efficacy and safety of gene therapy drugs wasdeveloped.
A transient, selective, and safe coating of the liver sinusoidal wall was achieved. Asa result, the clearance of gene therapy drugs was effectively prevented.
Consequently, the gene transfer efficiency into cardiac muscle, skeletal muscle, andcancer tissue was boosted.
This research will be published in Science Advances (IF = 12.804) on June 27 (JST).

5pm on June 26, 2020 – Kawasaki/Japan: The Innovation Center of NanoMedicine(iCONM), the National Institute for Quantum Science and Technology (QST), and theUniversity of Tokyo jointly announced that a reagent for the selective and safe coating of theliver sinusoidal walls to control the clearance of gene therapy drugs was successfully
developed. The contents of this research will be published in Science Advances by theAmerican Association for the Advancement of Science (AAAS) at 2:00 pm on June 26, east
coast of the United States (Japan standard time: 3:00 am on 27th): A. Dirisala, S. Uchida,
K. Toh, J. Li, S. Osawa, T. A. Tockary, X. Liu, S. Abbasi, K. Hayashi, Y. Mochida, S.
Fukushima, H. Kinoh, K. Osada, Kazunori Kataoka, ”Transient stealth coating of liver
sinusoidal wall by anchoring two-armed PEG for retargeting nanomedicines”.
Recently, gene therapies have been successively approved in Europe, US, and Japan, andare expected to provide novel therapeutic options for cancer, chronic diseases, acquired
and inherited genetic disorders. Whilst this is promising, in reality, when gene therapy drugs
are systemically administered to living organisms, they are rapidly eliminated andmetabolized in the liver, thus impeding the delivery of a sufficient amount to the target organs
and raising the toxicity concerns. This elimination by the liver is caused by the adsorption of
the gene therapy drugs to the vascular wall of the liver sinusoid, which is an intrahepatic
capillary. To overcome this issue, we conceived to selectively coat the liver sinusoidal wallusing polyethylene glycol (PEG). However, a long-term coating may impair the normal

physiological functions of the liver, and therefore the coating should be transient. In addition,
coating needs to be selective for liver sinusoids, as coating the blood vessels throughout
the body would not only cause adverse effects but also decrease the delivery amount ofgene therapy drugs to target organs. Towards this end, we have developed a coating agent
with two-armed PEG conjugated to positively charged oligolysine, which demonstrated theselective coating on the liver sinusoidal wall, the first-of-its-kind strategy in the world.
Interestingly, the coating with two-armed PEG was excreted into bile within 6 hours after
binding to sinusoidal walls, while the coating with single chain of linear PEG bound tooligolysine persisted in the walls for a long time. In this way, the precise molecular design
was necessary to achieve a transient coating.
This coating was subsequently applied to boost the delivery efficacy of gene therapy drugs.
Adeno-associated virus (AAV) is widely used for viral gene therapy drugs, and its serotype
8 (AAV8) targets myocardium and skeletal muscles. When AAV8 was administered afterprior coating of two-armed PEG to the liver sinusoidal wall, the transfer of AAV8 to the liver
was suppressed, and as a result, the gene transfer efficiency into the myocardium andskeletal muscles was improved by 2 to 4 times. This approach is promising for the treatmentof muscular dystrophy. In addition, we expanded the use of our strategy to virus-free genedelivery systems, which allows more economically attractive and safe gene therapy. We
have been working on non-viral gene therapy for malignant tumors using plasmid DNAequipped smart nanomachine for over 10 years. When the coating agent was used for thissystem, the adsorption of nanomachines to the sinusoidal wall was suppressed, resulting in
an approximately 10-fold improvement in DNA transfer efficiency to colon cancer. As
described above, we have succeeded in boosting the activity of gene therapy drugs while
ensuring safety by using the coating agent developed this time.
The above findings are summarized as follows:
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The coating agent with two-armed PEG selectively coated the liver sinusoid wall forseveral hours and was then excreted in the bile.
The coating agent with single chain of linear PEG is not excreted in bile and coatedthe liver sinusoidal wall for more than 9 hours, which raises a safety concern.
The coating agent with two-armed PEG had selectivity for the liver sinusoid wall,without coating the blood vessels in the connective tissues.
The coating agent improved the gene transfer efficacy to the myocardium andskeletal muscles using the AAV vector by 2 to 4 times, and the gene transfer
efficiency to colorectal cancer using DNA-loaded smart nanomachines by 10 times.
As a result, our approach is expected to allow for improving the effect of gene therapy
drugs and reducing their dose needed to obtain therapeutic outcome, which will leadto the reduction of medical cost and adverse event opportunities.

Innovation Center of NanoMedicine:
The Innovation Center of NanoMedicine (iCONM) is a leading facility of King Skyfront, thatis a biotech and healthtech innovation cluster in Kawasaki City. iCONM started the operationin April 2015 with Kawasaki Institute of Industrial Promotion in order to drive “Center of Open
Innovation Network for Smart Health (COINS)” as a part of Japanese governmental researchprogram “Center of Innovation (COI) Stream”. Designed for the purpose of promoting“open innovation” through industry-academia-government and medicine-engineeringcollaborations with state-of-the-art facilities and experimental equipment capable ofconducting the R&D from organic synthesis and micro-processing to preclinical studies. Thisis a very unique research center that is hardly found in the world.
https://iconm.kawasaki-net.ne.jp/en/index.html

National Institutes for Quantum and Radiological Science and Technology:
The National Institutes for Quantum and Radiological Science and Technology (QST) wasestablished in April 2016 to promote quantum science and technology in a comprehensive
and integrated manner. The new organization was formed from the merger of the National
Institute of Radiological Sciences (NIRS) with certain operations that were previously
undertaken by the Japan Atomic Energy Agency (JAEA). QST’s mission is to raise thelevel of quantum and radiological sciences and technologies through its commitment toresearch and development into quantum science and technology, the effect of radiation onhumans, radiation emergency medicine, and the medical use of radiation. To ensure that
research and development delivers significant academic, social and economic impacts, andto maximize benefits from global innovation, QST is striving to establish world-leading
research and development platforms, explore new fields, and serve as a center for radiation
protection and radiation emergency medicine.
https://www.qst.go.jp/site/qst-english/

Department of Bioengineering, Graduate School of Engineering, University ofTokyo:
In a society where the population ages and the birth rate declines with the sustainable
development being longed for, the Department of Bioengineering aims to contribute to thepromotion of health and well-being of the humanity. To achieve this goal, we promote theeducation and research of bioengineering, which is the multidisciplinary academic field
integrating the existing disciplines of engineering and those of life sciences at their interface.
The key features of bioengineering are to establish its theoretical basis by understanding
and clarifying the interactions of materials and systems with living bodies, and to develop
fundamental technologies that control these interactions based on the theory. The control of
the interactions with living bodies renders materials and systems far more useful andcompatible, promising the birth of groundbreaking medical technologies.
http://www.bioeng.t.u-tokyo.ac.jp/en/overview/index.html