INTRODUCTION: Obesity is a serious disease and a major risk factor for cardiovascular conditions, type 2 diabetes, and cancer. According to WHO, around 3.5 billion people worldwide are affected by overweight and obesity. Food intake and energy balance are regulated by anorexigenic POMC and orexigenic AgRP neurons located in the arcuate nucleus (Arc) of the hypothalamus. Their activity is modulated by peripheral signals such as leptin, insulin, and ghrelin, as well as by microRNAs that regulate gene expression. AgRP neurons, involved in food intake, are likely candidates and potential therapeutic targets. Adeno-associated viral (AAV) vectors are a promising tool for their precise manipulation. Careful selection of AAV capsid, ITRs, and gene regulatory elements may ensure specificity and efficiency.

AIM(S): We aimed to evaluate the transduction efficiency and specificity of various AAV capsid serotypes and ITR sequences in hypothalamic cells of C57Bl/6 mice, focusing on their ability to deliver Cre recombinase to specific neuronal populations, with particular emphasis on the Arc and AgRP neurons.

METHOD(S): We produce AAV vectors via triple transfection in a helper-free system. These vectors, incorporating various combinations of natural and synthetic capsids and ITR sequences, carry Cre recombinase. The vectors are stereotactically injected into the Arc region of C57Bl/6 mice. Two weeks post-injection, expression patterns are assessed through immunohistochemistry, focusing on transduced regions and specific cell types.

RESULTS: Results showed that different AAV configurations yield diverse expression patterns in the Arc region of C57Bl/6 mice.

CONCLUSIONS: Understanding the properties of individual components of AAV vectors can contribute to the development of highly precise tools for genetic manipulation, even of selected cell populations, which can aid in advancing gene therapies for complex diseases, enhancing the specificity and safety of treatments, and enabling personalized medicine approaches.

FINANCIAL SUPPORT: This work was funded by Łukasiewicz Research Network – PORT, Polish Center for Technology Development (statutory funds) and by National Science Centre (OPUS) grant 2019/35/B/NZ4/02831.