Systemic gene delivery transduces the enteric nervous system of guinea pigs and cynomolgus macaques

Abstract

Characterization of adeno-associated viral vector (AAV) mediated gene delivery to the enteric nervous system (ENS) was recently described in mice and rats. In these proof-of-concept experiments, we show that intravenous injections of clinically relevant AAVs can transduce the ENS in guinea pigs and non-human primates. Neonatal guinea pigs were given intravenous injections of either AAV8 or AAV9 vectors that contained a green fluorescent protein (GFP) expression cassette or PBS. Piglets were euthanized three weeks post-injection and tissues were harvested for immunofluorescent analysis. GFP expression was detected in myenteric and submucosal neurons along the length of the gastrointestinal tract in AAV8 injected guinea pigs. GFP positive neurons were found in dorsal motor nucleus of the vagus and dorsal root ganglia. Less transduction occurred in AAV9 treated tissues. Gastrointestinal tissues were analyzed from young cynomolgus macaques that received systemic injection of AAV9 GFP. GFP expression was detected in myenteric neurons of the stomach, small and large intestine. These data demonstrate that ENS gene delivery translates to larger species. This work develops tools for the field of neurogastroenterology to explore gut physiology and anatomy using emerging technologies such as optogenetics and gene editing. It also provides a basis to develop novel therapies for chronic gut disorders.

Optimization of AAV vectors to target persistent viral reservoirs

“…In mice, AAV8 and AAV9 vectors can efficiently transduce up to 57% of myenteric and submucosal neurons of the GI tract when delivered systemically via IV injection [ 163 , 164 ]. In guinea pigs, AAV8 can transduce myenteric and submucosal gut neurons when delivered IV [ 165 ]. In cynomolgus macaques, AAV9 can transduce myenteric neurons of the stomach and small and large intestine after IV administration [ 165 ].…”

“…In guinea pigs, AAV8 can transduce myenteric and submucosal gut neurons when delivered IV [ 165 ]. In cynomolgus macaques, AAV9 can transduce myenteric neurons of the stomach and small and large intestine after IV administration [ 165 ]. More recently, we were able to show that the neurons of the superior cervical ganglia (SCG), a part of the sympathetic ANS, can also be transduced with high efficiency by AAV vectors delivered IV.…”

Optogenetic control of the enteric nervous system and gastrointestinal transit

“…This can be performed by delivering genetic material to the gut by viral vectors [24]. Widespread induction of novel gene expression in enteric neurons has been achieved by intravenous or intraperitoneal administration of adeno-associated viruses (AAV) in mice [25–27], guinea pigs [28] and monkeys [28]. Local expression in the colonic ENS was achieved by focal intramural injections in rats and mice [29].…”

AAV-Mediated Gene Delivery to the Enteric Nervous System by Intracolonic Injection

“…infusion [6][7][8][9], sciatic nerve injection [8], or direct intraganglionic injection [10] has been described in a number of studies. AAV vectors have also been used successfully for transduction of enteric neurons by direct injection within the intestinal wall [11] as well as by systemic [12][13][14], and to a lesser extent intrathecal [15], administration. Therefore, the utility of AAV vectors for genetic manipulations of the intrinsic and extrinsic components of the enteric nervous system has been demonstrated.…”

“…1b). Viral titers of ~10 12 vector genomes (vg)/mL transduce approximately 30% of enteric neurons, while titers of ~10 13 vg/mL transduce over 70% of neurons [11]. Although to date only constructs with ubiquitous promoters have been used in the enteric nervous system, nonubiquitous promoters such as the promoter for the choline acetyltransferase gene may be employed to achieve preferential targeting of subtypes of enteric neurons.…”