Modulation of gene expression on a transcriptome-wide level following human neural stem cell transplantation in aged mouse stroke brains

by Selleckchem | Aug 04 2023

Introduction: Neural stem cell (NSC) transplantation offers great potential for treating ischemic stroke. Clinically, ischemia followed by reperfusion results in robust cerebrovascular injury that upregulates proinflammatory factors, disrupts neurovascular units, and causes brain cell death. NSCs possess multiple actions that can be exploited for reducing the severity of neurovascular injury. Our previous studies in young adult mice showed that human NSC transplantation during the subacute stage diminishes stroke pathophysiology and improves behavioral outcome.

Methods: We employed a well-established and commonly used stroke model, middle cerebral artery occlusion with subsequent reperfusion (MCAO/R). Here, we assessed the outcomes of hNSC transplantation 48 h post-MCAO (24 h post-transplant) in aged mouse brains in response to stroke because aging is a crucial risk factor for cerebral ischemia. Next, we tested whether administration of the integrin α5β1 inhibitor, ATN-161, prior to hNSC transplantation further affects stoke outcome as compared with NSCs alone. RNA sequencing (RNA-seq) was used to assess the impact of hNSC transplantation on differentially expressed genes (DEGs) on a transcriptome-wide level.

Results: Here, we report that hNSC-engrafted brains with or without ATN-161 showed significantly reduced infarct size, and attenuated the induction of proinflammatory factors and matrix metalloproteases. RNA-seq analysis revealed DEGs and molecular pathways by which hNSCs induce a beneficial post-stroke outcome in aged stroke brains. 811 genes were differentially expressed (651 downregulated and 160 upregulated) in hNSC-engrafted stroke brains. Functional pathway analysis identified enriched and depleted pathways in hNSC-engrafted aged mouse stroke brains. Depletion of pathways following hNSC-engraftment included signaling involving neuroinflammation, acute phase response, leukocyte extravasation, and phagosome formation. On the other hand, enrichment of pathways in hNSC-engrafted brains was associated with PPAR signaling, LXR/RXR activation, and inhibition of matrix metalloproteases. Hierarchical cluster analysis of DEGs in hNSC-engrafted brains indicate decreased expression of genes encoding TNF receptors, proinflammatory factors, apoptosis factors, adhesion and leukocyte extravasation, and Toll-like receptors.

Conclusions: Our study is the first to show global transcripts differentially expressed following hNSC transplantation in the subacute phase of stroke in aged mice. The outcome of our transcriptome study would be useful to develop new therapies ameliorating early-stage stroke injury.

Comments:

This study investigates the potential of neural stem cell (NSC) transplantation as a treatment for ischemic stroke. Ischemic stroke, characterized by cerebrovascular injury and brain cell death, can be mitigated by NSCs due to their various actions. Previous studies have shown positive outcomes of human NSC transplantation in young adult mice during the subacute stage of stroke. However, the effects of NSC transplantation in aged mouse brains, considering aging as a significant risk factor for stroke, and the impact of combining NSCs with an integrin α5β1 inhibitor called ATN-161 were yet to be explored. Additionally, the study aims to identify differentially expressed genes (DEGs) and molecular pathways affected by NSC transplantation using RNA sequencing (RNA-seq).

The researchers utilized a well-established stroke model, middle cerebral artery occlusion with subsequent reperfusion (MCAO/R), to induce stroke in aged mice. NSCs were transplanted into the mice's brains 48 hours after the stroke, and ATN-161 was administered prior to NSC transplantation to assess its combined effects. The outcomes measured included infarct size, induction of proinflammatory factors, and matrix metalloproteases.

The results indicate that NSC transplantation, with or without ATN-161, significantly reduced infarct size and attenuated the expression of proinflammatory factors and matrix metalloproteases. RNA-seq analysis revealed 811 DEGs in NSC-engrafted stroke brains, with 651 downregulated genes and 160 upregulated genes. Functional pathway analysis identified enriched and depleted pathways in NSC-engrafted aged mouse stroke brains. Pathways related to neuroinflammation, acute phase response, leukocyte extravasation, and phagosome formation were depleted, while pathways associated with PPAR signaling, LXR/RXR activation, and inhibition of matrix metalloproteases were enriched. Hierarchical cluster analysis of the DEGs revealed decreased expression of genes encoding TNF receptors, proinflammatory factors, apoptosis factors, adhesion and leukocyte extravasation molecules, and Toll-like receptors in NSC-engrafted brains.

In conclusion, this study provides insights into the global transcriptomic changes following NSC transplantation in aged mice during the subacute phase of stroke. The findings contribute to the development of novel therapies that can ameliorate early-stage stroke injury by targeting the identified pathways and DEGs.