Polyinosinic acid blocks adeno-associated virus macrophage endocytosis in vitro and enhances adeno-associated virus liver-directed gene therapy in vivo.

Abstract

Adeno-associated virus serotype 8 (AAV8) has been demonstrated to be effective for liver-directed gene therapy in humans. Although hepatocytes are the main target cell for AAV8, there is a loss of the viral vector because of uptake by macrophages and Kupffer cells. Reducing this loss would increase the efficacy of viral gene therapy and allow a dose reduction. The receptor mediating this uptake has not been identified; a potential candidate seems the macrophage scavenger receptor A (SR-A) that is involved in the endocytosis of, for instance, adenovirus. In this study we show that SR-A can mediate scAAV8 endocytosis and that blocking it with polyinosinic acid (poly[i]) reduces endocytosis significantly in vitro. Subsequently, we demonstrate that blocking this receptor improves scAAV-mediated liver-directed gene therapy in a model for inherited hyperbilirubinemia, the uridine diphospho-glucuronyl transferase 1A1-deficient Gunn rat. In male rats, preadministration of poly[i] increases the efficacy of a low dose (1×10¹¹ gc/kg) but not of a higher dose (3×10¹¹ gc/kg) scAAV8-LP1-UT1A1. Administration of poly[i] just before the vector significantly increases the correction of serum bilirubin in female rats. In these, the effect of poly[i] is seen by both doses but is more pronounced in the females receiving the low vector, where it also results in a significant increase of bilirubin glucuronides in bile. In conclusion, this study shows that SR-A mediates the endocytosis of AAV8 in vitro and in vivo and that blocking this receptor can improve the efficacy of AAV-mediated liver-directed gene therapy.

• Authors: Remco van Dijk, Paula S Montenegro-Miranda, Christel Riviere, Ronald Schilderink, Lysbeth ten Bloemendaal, Jacqueline van Gorp, Suzanne Duijst, Dirk R de Waart, Ulrich Beuers, Hidde J Haisma, Piter J Bosma
• Journal: Human gene therapy (Hum Gene Ther) Vol. 24 Issue 9 Pg. 807-13 (Sep 2013) ISSN: 1557-7422 [Electronic] United States
• PMID: 24010701 (Publication Type: Journal Article)

Chemical References

• Scavenger Receptors, Class A
• Poly I
• Glucuronosyltransferase
• Bilirubin

Topics

• Animals
• Bilirubin (blood)
• CHO Cells
• Cell Line
• Cricetulus
• Crigler-Najjar Syndrome (genetics, therapy)
• Dependovirus (immunology)
• Disease Models, Animal
• Endocytosis (drug effects)
• Female
• Genetic Therapy (methods)
• Genetic Vectors
• Glucuronosyltransferase (genetics)
• HEK293 Cells
• Hepatocytes (virology)
• Humans
• Kupffer Cells (drug effects, immunology)
• Liver (immunology, metabolism)
• Male
• Poly I (metabolism)
• Rats
• Scavenger Receptors, Class A (antagonists & inhibitors, drug effects, metabolism)
• Transduction, Genetic