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Description
Gastroparesis is characterized by severely delayed gastric emptying without physical obstruction, causing symptoms such as nausea, vomiting, and epigastric pain. Currently, no treatment reliably restores gastric emptying. Optogenetics involves genetically introducing light-sensitive proteins into target cells, enabling precise stimulation with high spatial and temporal resolution. We previously demonstrated that direct optogenetic stimulation of murine gastric smooth muscle cells (SMCs) with UV or blue light induces contractions and increases intragastric pressure in transgenic mice expressing Neuropsin (hOPN5) or Channelrhodopsin 2 (ChR2).
For clinical translation, an efficient gene delivery vector is needed to express optogenetic proteins in gastric SMCs in vivo. Adeno-associated viruses (AAVs) are widely used in gene therapy and have entered clinical use. We compared the transduction efficiency of various known AAV serotypes (1, 2, 3, 5, 6, 7, 8, 9, 10, eB, PHP) and the novel AAV2.5 in isolated murine gastric SMCs.
SMCs were isolated from CD-1 wild-type mice and incubated with increasing doses of each AAV. After six days, transduction efficiency was analyzed via fluorescence microscopy. Capsid variants AAV2.5, AAV2, AAV1, and AAV6 achieved expression rates above 40%. Notably, AAV2.5 showed more than a tenfold higher efficiency compared to others (log10(EC50): AAV2.5: 6.89 ± 0.12 vs. AAV2: 8.08 ± 0.08).
We identified AAV2.5 as a potent vector for gene transfer into gastric SMCs. The next steps include testing in human gastric SMCs and in vivo studies in mice.
