Publication: Exploring the Potential of Cell and Tissue Derived Extracellular Vesicle for the Development of Novel Neuro Therapeutics for Adult Neurogenesis
No Thumbnail Available
Date
2024-12-12
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Indian Institute of Technology, Jodhpur
Abstract
Aging and neurodegenerative diseases significantly impair adult neurogenesis, leading to reduced neuroplasticity and neuronal regeneration. This decline in neurogenesis, specifically within the subventricular zone (SVZ) and the hippocampus, is characterized by a reduction in neural stem cell (NSC) proliferation and an increased number of quiescent NSCs. As aging progresses, neurogenic populations within the brain become increasingly depleted, contributing to cognitive decline and neurodegenerative diseases such as Alzheimers and Parkinson’s disease. While current therapies such as stem cell transplantation and neurodegeneration prevention strategies offer potential, they have limited success in reversing age-related damage or promoting effective regeneration. Therefore, novel approaches that target the enhancement of NSC proliferation and differentiation are needed to combat these challenges. Extracellular vesicles (EVs), nanosized lipid bilayer vesicles secreted by cells, have emerged as a promising platform for therapeutic delivery due to their ability to traverse the blood-brain barrier and their non-invasive, non-immunogenic, and nontumorigenic properties. In particular, exosomes derived from stem cells and other tissue sources have been identified as potential mediators of cellular communication and regeneration, capable of promoting differentiation, proliferation, and survival of NSCs. In this study, we investigate the therapeutic potential of adipose tissue stem cell-derived EVs (Exo- Pep-11) engineered with a peptide targeting EphA4 receptors on NSCs. EphA4, a receptor specifically expressed by neural stem cells, is a member of the Eph receptor tyrosine kinase family, known for its involvement in developmental processes such as cell migration and differentiation. By designing a peptide-based ligand targeting the EphA4-Ephrin-B2 interaction, we conjugated this peptide with EVs, creating Exo-Pep-11, which is capable of specifically targeting NSCs through EphA4 receptors. Our results demonstrate that Exo-Pep- 11 efficiently internalizes into NSCs in both in vitro and in vivo models, enhancing their proliferation and differentiation, with significant potential for neurogenesis. In vitro assays show that Exo-Pep-11 significantly enhances the proliferation of NSCs, with a ~1.9-fold increase in cell proliferation and a ~2.4-fold increase in the expression of the ID1 protein, a key regulator of NSC proliferation. Moreover, we observe a ~1.4-fold increase in Nestin expression, a marker of undifferentiated NSCs. Importantly, the receptor-specific uptake of Exo-Pep-11 by NSCs is confirmed through pre-treatment with an EphA4-specific antibody, which reduces the uptake by approximately 2.3-fold, suggesting that the ligand-receptor interaction is crucial for the targeted delivery of the engineered EVs. These findings highlight the effectiveness of Exo-Pep-11 in enhancing NSC rejuvenation, an essential step in mitigating age-related decline in neurogenesis. Further, we explore the potential of Exo-Pep-11 in promoting neurogenesis in aging rats, specifically in the olfactory bulb (OB), a region known for continuous neurogenesis throughout life. In aging rats, neurogenesis is impaired, and the ability of NSCs to differentiate into functional neurons is reduced. However, treatment with Exo-Pep-11 leads to significant improvements in neurogenesis, with a ~1.6-fold and ~1.5-fold increase in the expression of tyrosine hydroxylase (TH) and Tuj1, respectively, in the aging rat OB. These results suggest that Exo-Pep-11 not only targets NSCs but also enhances their differentiation into dopaminergic neuronal subtypes, which is particularly relevant in the context of age-related neurodegenerative diseases such as Parkinson’s disease. In parallel, we investigate the neurogenic potential of EVs derived from the substantia nigra (SN) of rat brains. The SN is a key brain region involved in dopaminergic neurotransmission and is particularly susceptible to neurodegeneration in Parkinson’s disease. Using an aging rat model treated with 6-hydroxydopamine (6-OHDA) to induce dopaminergic neurodegeneration, we assess the role of SN-derived EVs in promoting dopaminergic neurogenesis and mitigating neurodegeneration. Our results reveal that EVs from 1-monthold rats (SN-EV-1) show the most potent effects in inducing NSCs to differentiate into dopaminergic neurons. In vivo, SN-EV-1 treatment increases the expression of dopaminergic markers, such as TH and dopamine transporter (DAT), and enhances NSC migration to the OB, providing strong evidence of the regenerative potential of SN-derived EVs in the context of neurodegeneration. We also demonstrate that SN-EV-1 treatment improves behavioural outcomes in the aging rat model, highlighting the neuroprotective and neurogenic properties of these vesicles. The therapeutic effects of SN-EV-1 are further supported by histological analysis, which reveals enhanced NSC differentiation and migration to the OB, underscoring the ability of SN-derived EVs to rejuvenate neurogenic niches in the aging brain. These findings establish a foundation for exploring SN-derived EVs as a potential therapy for neurodegenerative diseases like Parkinson’s disease, where dopaminergic neurodegeneration is a hallmark feature. In the continuation of our previous work, we have developed an efficient protocol for isolating SN-EVs and conducting subsequent proteomic studies. This research enhances our understanding of the potential of EVs, particularly those engineered to target NSCs, in rejuvenating aging neural populations and promoting neurogenesis. Additionally, it contributes to our understanding of disease mechanisms and biomarker discovery. With further optimization and clinical testing, these EV-based therapies and studies on EV mechanisms could provide a novel and effective strategy for addressing age-related cognitive decline and neurodegenerative diseases, offering new hope for patients suffering from conditions such as Parkinson’s disease, Alzheimer’s disease, and other neurodegenerative disorders.
Description
Keywords
Citation
Ghosh, Satyajit (2019).Exploring the Potential of Cell and Tissue Derived Extracellular Vesicle for the Development of Novel Neuro Therapeutics for Adult Neurogenesis (Doctor's thesis).Indian Institute of Technology, Jodhpur