TERT is a therapeutic target for tertiary stroke prevention.

INTRODUCTION

Tertiary stroke prevention aims to mitigate long-term disability and improve life quality for stroke survivors. While primary and secondary stroke prevention strategies have been extensively investigated, tertiary prevention remains a critically understudied area, and there is currently no clinically approved drug for tertiary stroke prevention.

OBJECTIVES

We previously discovered a transcription-regulatory function of telomerase reverse transcriptase (TERT) in cultured primary neurons. Here, we further explored the in vivo functional role of TERT in neural repair and functional recovery after ischemic stroke.

METHODS

We performed single-nucleus RNA sequencing (snRNA-seq) analysis in a photothrombosis (PT)-induced permanent ischemic stroke mouse model to characterize TERT expression in the cerebral peri-infarct tissue, which was verified by PT and middle cerebral artery occlusion (MCAO) mouse model with immunofluorescence analysis. CUT&Tag-sequencing was used to profile the whole-genome TERT binding loci and transcriptional activity in the isolated neurons from the peri-infarct tissue. We further used phospho-proteomic analysis to identify the signaling mechanism of TERT regulation in neurons.

RESULTS

snRNA-seq revealed TERT expression was increased in neurons in the peri-infarct tissue during the critical post-stroke recovery period in PT mice. This result was confirmed by immunofluorescent imaging in the PT and MCAO stroke models. Intravenous delivery of brain-targeted AAV-mediated neuron-specific overexpression of TERT significantly bolstered neural repair and functional recovery in the PT stroke model. Additionally, pharmacological upregulation of TERT expression in post-stroke recovery period by oral gavage of cycloastragenol (CAG) conferred prominent neural repair, improved sensorimotor functional recovery and alleviated post-stroke depression-like behaviors. Knockdown of neuronal TERT abolished the spontaneous and CAG-induced neural repair-promoting effect in PT mice. Mechanistically, we discovered that neuronal TERT is a transcriptional co-regulator of CREB-target genes including GAP43, EVL, NR4A3, and NRP2 which are associated with enhanced axon sprouting, dendritic branching and synaptogenesis in recovery phase of PT stroke. We further demonstrated that CAG upregulates TERT expression by promoting STAT3 phosphorylation at serine 727 in a DAPK1-dependent manner.

CONCLUSION

Overall, these results demonstrate that TERT is a promising therapeutic target for tertiary stroke prevention.