KLF2 Is Associated with ERK1/2-MAP2 Activation and Neuron-like Phenotypic Remodeling of PDGFR-β-Lineage Cells Following Ischemic Stroke.

Background/

Objectives

Ischemic stroke (IS) induces substantial phenotypic remodeling within the neurovascular unit, and pericytes have been implicated in the cellular responses to ischemic injury. However, the molecular characteristics and regulatory mechanisms underlying pericyte phenotypic remodeling after ischemic stroke remain incompletely understood.

Methods

In this study, we used PDGFR-β-CreERT2; ZsGreen lineage-tracing mice and a middle cerebral artery occlusion (MCAO) model to characterize the temporal changes in PDGFR-β-lineage cells following ischemic injury. In vitro, human brain vascular pericytes (HBVPs) exposed to oxygen-glucose deprivation/reperfusion (OGD/R) and subsequently maintained in neurobasal medium to examine ischemia-related phenotypic changes. The involvement of KLF2-associated signaling was further investigated using KLF2 knockdown approaches.

Results

We observed increased expression of Nestin in PDGFR-β-lineage cells during the early post-ischemic period, followed by the emergence of subsets co-expressing GFAP or DCX during the subacute stage. These findings indicate the acquisition of neuroglial- and neuronal-associated molecular features, rather than providing definitive evidence of lineage conversion or functional differentiation. The expression of these markers declined at later stages, whereas PDGFR-β-lineage cells were also associated with vascular remodeling during the recovery phase. In vitro, OGD/R-treated HBVPs exhibited increased expression of DCX, MAP2, and NeuN. KLF2 knockdown attenuated these molecular changes. Consistently, OGD/R was associated with increased KLF2, phosphorylated ERK1/2, and MAP2 expression, whereas KLF2 knockdown reduced ERK1/2 phosphorylation and MAP2 expression. These findings suggest that KLF2 is associated with ERK1/2 activation and MAP2 expression during ischemia-related phenotypic remodeling of PDGFR-β-lineage cells.

Conclusions

Overall, our results identify transient neuroglial- and neuronal-associated molecular changes in pericytes after ischemic injury and provide evidence for an association between KLF2 and ERK1/2-MAP2 signaling in this process, while further studies are required to determine whether these changes represent stable lineage conversion or functional neuronal differentiation.