TAT-PEP Enhanced Neurobehavioral Functional Recovery by Facilitating Axonal Regeneration and Corticospinal Tract Projection After Stroke

Abstract

Paired immunoglobulin-like receptor B (PirB) has been identified as a new receptor for myelin-associated inhibitory (MAI) proteins, which may play important role in axonal regeneration and corticospinal tract (CST) projection associated with neurobehavioral function recovery after stroke. Here, we found that the expression of PirB was increased in the cortical penumbra from 1 to 28 days after transient focal cerebral ischemic reperfusion of rats. Then, transactivator of transcription-PirB extracellular peptide (TAT-PEP) was generated that might block the interactions between MAIs and PirB. The results showed that TAT-PEP displayed high affinity for MAIs and ameliorated their inhibitory effect on neurite growth. Furthermore, TAT-PEP can widely distribute in the penumbra after intraperitoneal injection. Then, we found that TAT-PEP enhanced neurite growth and alleviated growth cone collapse after oxygen glucose deprivation (OGD) injury. In addition, TAT-PEP promoted long-term neurobehavioral functional recovery through enhancing axonal regeneration and CST projection. Finally, the observations demonstrated that POSH/RhoA/growth-associated protein 43 (GAP43) as PirB-associated downstream signaling molecules played important role in neurobehavioral functional recovery after stroke. Moreover, the underlying mechanism associated with TAT-PEP-mediated promoting axonal regeneration and CST projection was by intervening in the expression of POSH, RhoA, and GAP43. These studies suggest that TAT-PEP may represent an attractive therapeutic strategy against stroke.

Inhibition of PirB Activity by TAT-PEP Improves Mouse Motor Ability and Cognitive Behavior

“…TAT-PEP, a recombinant protein consisting of PirB extracellular motif fused with TAT, which demonstrated the ability to rescue neurite outgrowth inhibition induced by Nogo, MAG and OMgp in stroke (Deng et al, 2016), was used to treat PC12 PirB . Results in Figure 2C showed that treatment with TAT-PEP effectively prolonged the growth of axon.…”

“…TAT-PEP (PirB extracellular peptide) construction, expression and purification were carried out as previously reported (Deng et al, 2016). Briefly, cDNA of extracellular domain of PirB was synthesized and cloned into expression vector pTAT-HA-6xHis.…”

“…The size and purity were confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). As a control peptide, the scrambled PEP fusion protein named as TAT-mPEP was expressed and purified according to the same procedure used for TAT-PEP (Deng et al, 2016). …”

“…The expression of PirB was also found to gradually increase in the CA1 and DG subregions of the hippocampus in aging mice with cognitive behavior deficits (VanGuilder Starkey et al, 2012). Blocking PirB receptor could enhance both the short-term and long-term cognitive functions after bilateral common carotid artery occlusion in mice (Deng et al, 2016; Li et al, 2017). However, neither the association between PirB and cognition in normal brain development nor whether PirB can be used as a pharmacological target for modulating cognitive functions has been previously studied.…”

Nogo receptor antagonist LOTUS exerts suppression on axonal growth‐inhibiting receptor PIR‐B

“…Paired immunoglobulin‐like receptor (PIR)‐B, which is a well‐known receptor for major histocompatibility complex class I (MHCI) (Nakamura, Kobayashi, & Takai, 2004), has been identified as a novel receptor for these three MAIs and mediates induction of axonal growth inhibition by the MAIs (Atwal et al, 2008). PIR‐B is expressed in CNS neurons (Deng et al, 2018; Syken, Grandpre, Kanold, & Shatz, 2006). The expression of PIR‐B is drastically increased in injured CNS tissues (Adelson et al, 2012; Deng et al, 2018).…”