Cerebrospinal fluid-derived extracellular vesicles after spinal cord injury promote vascular regeneration via PI3K/AKT signaling pathway

Chengjun Li; Tian Qin; Yuxin Jin; Jianzhong Hu; Feifei Yuan; Yong Cao; Chunyue Duan

doi:10.1016/j.jot.2023.02.001

Cerebrospinal fluid-derived extracellular vesicles after spinal cord injury promote vascular regeneration via PI3K/AKT signaling pathway

J Orthop Translat. 2023 Mar 4:39:124-134. doi: 10.1016/j.jot.2023.02.001. eCollection 2023 Mar.

Authors

Chengjun Li^{1

2

3}, Tian Qin^{1

2

3}, Yuxin Jin^{1

2

3}, Jianzhong Hu^{1

2

3}, Feifei Yuan^{1

2

3}, Yong Cao^{1

2

3}, Chunyue Duan^{1

2

3}

Affiliations

¹ Department of Spine Surgery and Orthopaedics, Xiangya Hospital, Central South University, Xiangya Road 87, Changsha, 410008, China.
² Key Laboratory of Organ Injury, Aging and Regenerative Medicine of Hunan Province, Xiangya Road 87, Changsha, 410008, China.
³ National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Xiangya Road 87, Changsha, 410008, China.

Abstract

Background: The cerebrospinal fluid (CSF), which surrounds the brain and spinal cord, is predominantly produced by the choroid plexus of the ventricle. Although CSF-derived extracellular vesicles (CSF-EVs) may be utilized as diagnostic and prognostic indicators for illnesses of the central nervous system (CNS), it is uncertain if CSF-EVs may have an impact on neurological function after spinal cord injury (SCI).

Methods: Here, we isolated EVs using ultracentrifugation after extracting CSF from Bama miniature pigs. We then combined CSF-EVs with hydrogel and put it on the spinal cord's surface. To determine if CSF-EVs had an impact on mice's neurofunctional recovery, behavioral evaluations were employed. Both in vitro and in vivo, the effect of CSF-EVs on angiogenesis was assessed. We investigated whether CSF-EVs stimulated the PI3K/AKT pathway to alter angiogenesis using the PI3K inhibitor LY294002.

Results: CSF-EVs were successfully isolated and identified by transmission electron microscope (TEM), nano-tracking analysis (NTA), and western blot. CSF-EVs could be ingested by vascular endothelial cells as proved by in vivo imaging and immunofluorescence. We demonstrated that CSF-EVs derived from pigs with SCI (SCI-EVs) showed a better effect on promoting vascular regeneration as compared to CSF-EVs isolated from pigs receiving laminectomy (Sham-EVs). Behavioral assessments demonstrated that SCI-EVs could dramatically enhance motor and sensory function in mice with SCI. Western blot analysis suggested that SCI-EVs promote angiogenesis by activating PI3K/AKT signaling pathway, and the pro-angiogenetic effect of SCI-EVs was attenuated by the application of the LY294002 (PI3K inhibitor).

Conclusion: Our study revealed that CSF-EVs could enhance vascular regeneration by activating the PI3K/AKT pathway, hence improving motor function recovery after SCI, which may offer potential novel therapeutic options for acute SCI.

The translational potential of this article: This study demonstrated the promotion of vascular regeneration and neurological function of CSF-derived exosomes, which may provide a potential therapeutic approach for the treatment of spinal cord injury.

Keywords: Cerebrospinal fluid; Extracellular vesicles; PI3K-AKT pathway; Spinal cord injury; Vascular regeneration.