Viral vector-mediated selective and reversible blockade of the pathway for visual orienting in mice

Abstract

Recently, by using a combination of two viral vectors, we developed a technique for pathway-selective and reversible synaptic transmission blockade, and successfully induced a behavioral deficit of dexterous hand movements in macaque monkeys by affecting a population of spinal interneurons. To explore the capacity of this technique to work in other pathways and species, and to obtain fundamental methodological information, we tried to block the crossed tecto-reticular pathway, which is known to control orienting responses to visual targets, in mice. A neuron-specific retrograde gene transfer vector with the gene encoding enhanced tetanus neurotoxin (eTeNT) tagged with enhanced green fluorescent protein (EGFP) under the control of a tetracycline responsive element was injected into the left medial pontine reticular formation. 7–17 days later, an adeno-associated viral vector with a highly efficient Tet-ON sequence, rtTAV16, was injected into the right superior colliculus. 5–9 weeks later, the daily administration of doxycycline (Dox) was initiated. Visual orienting responses toward the left side were impaired 1–4 days after Dox administration. Anti-GFP immunohistochemistry revealed that a number of neurons in the intermediate and deep layers of the right superior colliculus were positively stained, indicating eTeNT expression. After the termination of Dox administration, the anti-GFP staining returned to the baseline level within 28 days. A second round of Dox administration, starting from 28 days after the termination of the first Dox administration, resulted in the reappearance of the behavioral impairment. These findings showed that pathway-selective and reversible blockade of synaptic transmission also causes behavioral effects in rodents, and that the crossed tecto-reticular pathway clearly controls visual orienting behaviors.

Large-Scale Chondroitin Sulfate Proteoglycan Digestion with Chondroitinase Gene Therapy Leads to Reduced Pathology and Modulates Macrophage Phenotype following Spinal Cord Contusion Injury

“…Additionally, although previous studies have found no enhanced pain sensitivity following ChABC treatment (Barritt et al, 2006;Galtrey et al, 2007;Karimi-Abdolrezaee et al, 2010) and in the present study LV-ChABC did not lead to enhanced sensitivity to noxious or non-noxious stimuli up to 12 weeks post-treatment, we do not know whether longer-term large-scale CSPG digestion could eventually have detrimental effects. Therefore, it would be optimal to regulate ChABC gene expression, for example by using an LV with an inducible promoter (Blesch et al, 2005;Sooksawate et al, 2013).…”

Serotype-dependent transduction efficiencies of recombinant adeno-associated viral vectors in monkey neocortex

“…6 In neuroscience, several methods have recently been introduced to control neural activity with unprecedented specificity. Methods such as optogenetics, [7][8][9][10][11] "designer receptors exclusively activated by designer drugs" (in short, DREADD) [12][13][14] and the double-infection technique (DIT), 15,16 rely mainly on viral vectors to introduce genes encoding light-sensitive proteins (opsins), artificial receptors (DREADD), or neurotoxins (DIT) into neurons. Transduction of specific subsets of cells (i.e., tropism) is inherent to the viral vector used and depends on the interaction between viral vector envelope/capsid and receptors on the cell membrane.…”

Selective Manipulation of Neural Circuits

“…Only the neurons co-infected with both viruses express the genetic tool and are manipulated. This dual viral infection system has been applied and controlled diverse circuits [41][42][43][44]. This strategy provides the most flexibility to target circuits; one needs only to know the origin and termination of a circuit.…”

“…Thus, it has a relatively long latency of several days to reach to the maximum inactivation level after stimulation. The latency can be various from 2 to 7 or more days according to the length of the targeted circuit because TeNT has to travel from the soma to the axon terminal [41][42][43]. This long time period allows other circuits to adapt to the loss of transmission within the targeted circuit [42,43].…”