Biodistribution of adeno-associated virus serotype 9 (AAV9) vector after intrathecal and intravenous delivery in mouse

Abstract

Adeno-associated virus serotype 9 (AAV9)-mediated gene transfer has been reported in central nervous system (CNS) and peripheral tissues. The current study compared the pattern of expression of Green Fluorescent Protein (GFP) across the mouse CNS and selected peripheral tissues after intrathecal (i.t.) or intravenous (i.v.) delivery of equivalent doses of single-stranded AAV9 vector. After i.t. delivery, GFP immunoreactivity (-ir) was observed in spinal neurons, primary afferent fibers and corresponding primary sensory neurons at all spinal levels. Robust transduction was seen in small and large dorsal root ganglion (DRG) neurons as well as trigeminal and vagal primary afferent neurons. Transduction efficiency in sensory ganglia was substantially lower in i.v. treated mice. In brain, i.v. delivery yielded GFP-immunoreactivity (-ir) primarily in spinal trigeminal tract, pituitary, and scattered isolated neurons and astrocytes. In contrast, after i.t. delivery, GFP-ir was widespread throughout CNS, with greater intensity and more abundant neuropil-like staining at 6 weeks compared to 3 weeks. Brain regions with prominent GFP-ir included cranial nerve nuclei, ventral pons, cerebellar cortex, hippocampus, pituitary, choroid plexus, and selected nuclei of midbrain, thalamus and hypothalamus. In cortex, GFP-ir was associated with blood vessels, and was seen in both neurons and astrocytes. In the periphery, GFP-ir in colon and ileum was present in the enteric nervous system in both i.v. and i.t. treated mice. Liver and adrenal cortex, but not adrenal medulla, also showed abundant GFP-ir after both routes of delivery. In summary, i.t. delivery yielded higher transduction efficiency in sensory neurons and the CNS. The observation of comparable gene transfer to peripheral tissues using the two routes indicates that a component of i.t. delivered vector is redistributed from the subarachnoid space to the systemic circulation.

Copackaged AAV9 Vectors Promote Simultaneous Immune Tolerance and Phenotypic Correction of Pompe Disease

“…16,41 Although it is recognized that GAA expressed from the desmin promoter would similarly be unable to cross the blood-brain barrier, evidence of crossing the blood-brain barrier by AAV9 would confer cell autonomous correction of the CNS. 59,76 Building on success with AAV9-DES-GAA to attenuate functional decline of cardiac, respiratory, and skeletal muscle pathology in Pompe disease, we have applied a new paradigm to address both the immunological and neuromuscular complications using a copackaged, dual-AAV9 vector system that addresses the multisystem disease progression simultaneous with overcoming immune-related complications, which is likely to have the most persistent therapeutic benefit and increase survival rates. 11,37,46,47 The induction of immune tolerance enhances the success of gene therapy.…”

“…AAV8 was selected because of its natural propensity to target the liver and increase levels of T regs , and AAV9 was chosen because of its widespread transduction profile. 24,30,59,60 Gaa -/-mice (4-6 weeks old; n = 4/group) received AAV-GAA at two IV doses: 0.5 · 10 12 (low dose) or 5 · 10 12 (high dose) vg/kg of AAV8-or AAV9-LSPcoGAA and compared with lactated Ringer's solution (vehicle). At 8 weeks post-gene transfer, hepatic GAA activity was evaluated and showed a dosedependent response compared with vehicle-injected mice: 133 -32% of wild type in low dose AAV8-LSPcoGAA, 509 -10% of wild type in high dose AAV8-LSP-coGAA, 56 -26% of wild type in low-dose AAV9-LSP-coGAA, and 312 -25% of wild type in high-dose AAV9-LSP-coGAA ( p < 0.01; Fig.…”

Proof‐of‐concept: neonatal intravenous injection of adeno‐associated virus vectors results in successful transduction of myenteric and submucosal neurons in the mouse small and large intestine

“…12 It should be noted that the systemic distribution of intravenously injected AAV is not limited to the ENS. 4,5,13 In the light of gene therapy, future efforts should evaluate specificity-enhancing strategies such as ENS-specific promotors, AAV with modified glycan binding ability or micro-RNAs. 14,15 Enteric glia lacked transgene expression, but these cells could be targeted with other AAV serotypes or GFAP promotor-driven constructs, as these strategies have been proven successful in earlier work.…”

“…[1][2][3] Recombinant adenoassociated viruses vectors (AAVs) belong to the most promising candidate vector systems in gene therapy and preclinical research 1,3 , but hitherto little is known about the transduction efficiency of the ENS by AAV. Rahim et al 4 and Schuster et al 5 have preliminarily indicated transduction of the myenteric plexus of the mouse with AAV9, and a more recent paper by Gombash et al 6 has detailed myenteric plexus transduction by self-complementary AAV9 in neonate and juvenile mice with green fluorescent protein (GFP) being expressed under a chicken-b-actin/cytomegalovirus (CB) hybrid promoter. However, data on submucosal plexus transduction are currently lacking, as is quantification of the neuronal subtypes transduced by AAV.…”

Gene therapy for the CNS using AAVs: The impact of systemic delivery by AAV9

“…For instance, Shuster et al [133] observed comparable levels of peripheral transduction using IV and intrathecal injections, suggesting that a fraction of IT delivered vector is moved from the subarachnoid space to systemic circulation. Moreover, according to Samaranch et al.…”