A comparison of in vivo viral targeting systems identifies adeno-associated virus serotype 9 (AAV9) as an effective vector for genetic manipulation of Leydig cells in adult mice.
BACKGROUND
Despite the increasing popularity of deliverable transgenics, a robust and fully validated method for targeting Leydig cells, capable of delivering long-term transgene expression, is yet to be defined.


OBJECTIVES
We compared three viral vector systems in terms of their cell targeting specificity, longevity of gene expression and impact on targeted cell types when delivered to the interstitial compartment of the mouse testis.


MATERIALS & METHODS
We delivered lentiviral, adenoviral and adeno-associated (AAV) viral particles to the interstitial compartment of adult mouse testis. Immunolocalization and stereology were performed to characterize ability of vectors to target and deliver transgenes to Leydig cells.


RESULTS
Viral vectors utilized in this study were found to specifically target Leydig cells when delivered interstitially. Transgene expression in lentiviral-targeted Leydig cells was detected for 7 days post-injection before Leydig cells underwent apoptosis. Adenoviral-delivered transgene expression was detected for 10 days post-injection with no evidence of targeted cell apoptosis. We found serotype differences in AAV injected testis with AAV serotype 9 targeting a significant proportion of Leydig cells. Targeting efficiency increased to an average of 59.63% (and a maximum of 80%) of Leydig cells with the addition of neuraminidase during injection. In AAV injected testis sections, transgene expression was detectable for up to 50 days post-injection.


DISCUSSION & CONCLUSION
Lentivirus, Adenovirus and Adeno-Associated virus delivery to the testis resulted in key variances in targeting efficiency of Leydig cells and in longevity of transgene expression, but identified AAV9 + Neuraminidase as an efficient vector system for transgene delivery and long-term expression. Simple viral delivery procedures and the commercial availability of viral vectors suggests AAV9 + Neuraminidase will be of significant utility to researchers investigating the genetics underpinning Leydig cell function and holds promise to inform the development of novel therapeutics for the treatment of male reproductive disorders.
['Darbey|Annalucia|A|0000-0001-8541-5472', 'Rebourcet|Diane|D|', 'Curley|Michael|M|', 'Kilcoyne|Karen|K|', 'Jeffery|Nathan|N|', 'Reed|Natalie|N|', 'Milne|Laura|L|', 'Roesl|Cornelia|C|', 'Brown|Pamela|P|', 'Smith|Lee B|LB|']
D000256:Adenoviridae D000818:Animals D000229:Dependovirus D018014:Gene Transfer Techniques D005822:Genetic Vectors D016086:Lentivirus D007985:Leydig Cells D008297:Male D051379:Mice
adeno-associated virus Leydig cell viral vector testis lentivirus adenovirus