Ngn2 failed to induce astrocyte-to-neuron reprogramming after intracerebral hemorrhage

Intracerebral hemorrhage (ICH) is a severe neurological disorder with high mortality due to neuronal loss, and current therapies face significant challenges. Cell reprogramming offers a potential solution. This study explores whether Neurogenin2 (Ngn2) can reprogram astrocytes into neurons in ICH models.

Primary mouse astrocytes were infected with Ngn2-overexpressing lentiviruses to optimize reprogramming conditions. In vitro reprogramming was tested under PDL and Matrigel coatings with bFGF support, and simulated ICH conditions using hemin. In vivo, an ICH model was induced in mice with type Ⅶ collagenase, and AAV5: F-Ngn2-GFP vectors were administered at 3, 7, and 21 days post-ICH. Neuronal conversion was assessed by immunofluorescence.

In vitro, Ngn2 induced astrocyte-to-neuron conversion under Matrigel and bFGF conditions, but efficiency was reduced in hemin-treated ICH models. In vivo, Ngn2 overexpression failed to induce reprogramming at any tested time point. Analysis revealed that AAV5 vectors were engulfed by microglia, likely contributing to reprogramming failure.

Ngn2-mediated reprogramming is effective in vitro but insufficient in vivo due to post-ICH inflammation and microglial phagocytosis. Future work should explore additional factors to enhance reprogramming efficiency.

The study was supported by the funding from National Natural Science Foundation of China (82071330), Major Program of Hubei Province (2023BAA005), and the Research Fund of Tongji Hospital (2022ZHFY01).