Expression-based selection identifies a microglia-tropic AAV capsid for direct and CSF routes of administration in mice

bioRxiv (Cold Spring Harbor Laboratory)

Abstract

Abstract Microglia are critical innate immune cells of the brain. In vivo targeting of microglia using gene-delivery systems is crucial for studying brain physiology and developing gene therapies for neurodegenerative diseases and other brain disorders such as NeuroAIDS. Historically, microglia have been extremely resistant to transduction by viral vectors, including adeno-associated virus (AAV) vectors. Recently, there has been some progress demonstrating the feasibility and potential of using AAV to transduce microglia after direct intraparenchymal vector injection. Data suggests that combining specific AAV capsids with microglia-specific gene expression cassettes to reduce neuron off-targeting will be key. However, no groups have developed AAV capsids for microglia transduction after intracerebroventricular (ICV) injection. The ICV route of administration has advantages such as increased brain biodistribution while avoiding issues related to systemic injection. Here, we performed an in vivo selection using an AAV peptide display library that enables recovery of capsids that mediate transgene expression in microglia. Using this approach, we identified a capsid, MC5, which mediated enhanced transduction of microglia after ICV injection compared to AAV9. Furthermore, MC5 enhanced both the efficiency (85%) and specificity (93%) of transduction compared to a recently described evolved AAV9 capsid for microglia targeting after direct injection into the brain parenchyma. Exploration of the use of MC5 in a mouse models of Alzheimer’s disease revealed transduced microglia surrounding and within plaques. Overall, our results demonstrate that the MC5 capsid is a useful gene transfer tool to target microglia in vivo by direct and ICV routes of administration.

Authors 13

1. Miguel C. Santoscoy

   Harvard University · Massachusetts General Hospital

   Affiliation as printed

   Department of Neurology, Massachusetts General Hospital, Boston, MA, 02115

   Harvard Medical School, Boston, MA, 02116

   Molecular Neurogenetics Unit, Massachusetts General Hospital, Charlestown, MA, 02129

2. Paula Espinoza

   Harvard University · Massachusetts General Hospital

   Affiliation as printed

   Department of Neurology, Massachusetts General Hospital, Boston, MA, 02115

   Harvard Medical School, Boston, MA, 02116

   Molecular Neurogenetics Unit, Massachusetts General Hospital, Charlestown, MA, 02129

3. Killian S. Hanlon

   Harvard University · Massachusetts General Hospital · University College London

   Affiliation as printed

   Department of Neurology, Massachusetts General Hospital, Boston, MA, 02115

   Harvard Medical School, Boston, MA, 02116

   Molecular Neurogenetics Unit, Massachusetts General Hospital, Charlestown, MA, 02129

   University College London, London, United Kingdom

4. Lisa Nieland Aachen Department of Neurosurgery, Leiden University Medical Center

   Leiden University Medical Center · Massachusetts General Hospital

   Affiliation as printed

   Department of Neurology, Massachusetts General Hospital, Boston, MA, 02115

   Department of Neurosurgery, Leiden University Medical Center, Leiden, 2300 RC, The Netherlands

   Molecular Neurogenetics Unit, Massachusetts General Hospital, Charlestown, MA, 02129

5. Carrie Ng

   Harvard University · Massachusetts General Hospital

   Affiliation as printed

   Department of Neurology, Massachusetts General Hospital, Boston, MA, 02115

   Harvard Medical School, Boston, MA, 02116

   Molecular Neurogenetics Unit, Massachusetts General Hospital, Charlestown, MA, 02129

6. Christian Elias Badr

   Harvard University · Massachusetts General Hospital

   Affiliation as printed

   Department of Neurology, Massachusetts General Hospital, Boston, MA, 02115

   Harvard Medical School, Boston, MA, 02116

   Molecular Neurogenetics Unit, Massachusetts General Hospital, Charlestown, MA, 02129

7. Suzanne E. Hickman

   Massachusetts General Hospital

   Affiliation as printed

   Department of Medicine, Center for Immunology and Inflammatory Disease, Massachusetts General Hospital, Boston, USA

8. Demitri de la Cruz

   Harvard University · Massachusetts General Hospital

   Affiliation as printed

   Department of Neurology, Massachusetts General Hospital, Boston, MA, 02115

   Harvard Medical School, Boston, MA, 02116

   Molecular Neurogenetics Unit, Massachusetts General Hospital, Charlestown, MA, 02129

9. Ana Griciuc

   Massachusetts General Hospital

   Affiliation as printed

   Genetics and Aging Research Unit, McCance Center for Brain Health, Mass General Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital, Charlestown, MA 02129, USA

10. Joseph B. El Khoury

    Massachusetts General Hospital

    Affiliation as printed

    Department of Medicine, Center for Immunology and Inflammatory Disease, Massachusetts General Hospital, Boston, USA

11. Rachel E. Bennett

    Harvard University · Massachusetts General Hospital

    Affiliation as printed

    Department of Neurology, Massachusetts General Hospital, Boston, MA, 02115

    Harvard Medical School, Boston, MA, 02116

12. Shiqian Shen

    Harvard University · Massachusetts General Hospital

    Affiliation as printed

    Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Havard Medical School, Boston, MA 02121

13. Casey A. Maguire corresponding

    Harvard University · Massachusetts General Hospital

    Affiliation as printed

    Department of Neurology, Massachusetts General Hospital, Boston, MA, 02115

    Harvard Medical School, Boston, MA, 02116

    Molecular Neurogenetics Unit, Massachusetts General Hospital, Charlestown, MA, 02129