Ability of Local Clearance of Senescent Cells in Ipsilateral Hemisphere to Mitigate Acute Ischemic Brain Injury in Mice

Abstract

Senolytic treatment has potential therapeutic efficacy for acute ischemic stroke (AIS). However, the systemic treatment of senolytics may produce off-target side effects and a toxic profile, which affect analysis of the role of acute senescence of neuronal cells in pathogenesis of AIS. We constructed a novel lenti-INK-ATTAC viral vector to introduce INK-ATTAC genes to the ipsilateral brain and locally eliminate senescent brain cells by administering AP20187 to activate caspase-8 apoptotic cascade. In this study, we have found that acute senescence is triggered by middle cerebral artery occlusion (MCAO) surgery, particularly in astrocytes and cerebral endothelial cells (CECs). The upregulation of p16 INK4a and senescence-associated secretory phenotype (SASP) factors including matrix metalloproteinase-3, interleukin-1 alpha and -6 were observed in oxygen-glucose deprivation-treated astrocytes and CECs. The systemic administration of a senolytic, ABT-263, prevented the impairment of brain activity from hypoxic brain injury in mice, and significantly improved the neurological severity score, rotarod performance, locomotor activity, and weight loss. The treatment of ABT-263 reduced senescence of astrocytes and CECs in MCAO mice. Furthermore, the localized removal of senescent cells in the injured brain through the stereotaxical injection of lenti-INK-ATTAC viruses generates neuroprotective effects, protecting against acute ischemic brain injury in mice. The content of SASP factors and mRNA level of p16 INK4a in the brain tissue of MCAO mice were significantly reduced by the infection of lenti-INK-ATTAC viruses. These results indicate that local clearance of senescent brain cells is a potential therapy on AIS, and demonstrate the correlation between neuronal senescence and pathogenesis of AIS.

Senolytic treatment depletes microglia and decreases severity of experimental autoimmune encephalomyelitis

“…This would be in line with the known function of senescence-associated secretory phenotype, where senescent cells secrete a collection of proinflammatory factors that lead to persistent low-grade tissue inflammation and injury 19 . However, the data presented in this manuscript do not rule out the possibility that other non-microglial senescent cells are being targeted by ABT-263 and contributing to the observed phenotype, as ABT-263 has been demonstrated in other studies to have profound effects on various senescent cell populations (Table 1 22,47–57 ).…”

Senescence and SASP Are Potential Therapeutic Targets for Ischemic Stroke

“…Previous studies demonstrated that ABT-263, FOXO4-D-Retro-Inverso peptide, and a combination of dasatinib and quercetin modulated inflammatory response and eliminated senescent cells, thereby attenuating IR associated cardiac and renal injury [ 100 , 101 , 102 , 103 ]. However, ABT-263 has only been validated in animal model of ischemic stroke [ 77 , 83 ]. Senomorphs are agents that prevent cell cycle arrest, rather than eliminating senescent cells, and attenuate the secretion of SASP [ 104 ].…”

“…Immuno-histochemical analysis of an autopsy human brain sample showed that an increased p16 level was observed in the perimeter of the infarct area [ 33 ]. Similarly, increased mRNA expression of p16 , Il-6 , Ccl8 , and Cxcl2 were detected in the ipsilateral cortex, striatum, and hippocampus from 6-12h in a mouse model of MCAO [ 77 ]. Immuno-histochemical analysis revealed that increased expression of senescent markers was predominantly localized in astrocytes and endothelial cells rather than neurons and microglia in the ipsilateral region.…”

“…To counteract any later non-specific effect, Lu et al demonstrated that the ipsilateral administration of a novel lenti-INK-ATTAC viral vector that delivers ATTAC (apoptosis through targeted activation of caspase) gene, which was specifically designated to eliminate senescent cells in the brain, could provide neuroprotection in ischemic stroke. INK-ATTAC causes the inducible elimination of p16 (Ink4a)-positive senescent cells upon administration of the inducer, AP20187 [ 77 ], demonstrating that local clearance of senescent cells is a possible therapeutic avenue for ischemic stroke.…”

Cellular Senescence as a Targetable Risk Factor for Cardiovascular Diseases

“… 54 , 55 Navitoclax has shown promise in eliminating senescent cells following cerebral IRI, reducing infarct volume, and improving neurological function in rats. 54 , 56 Also, chronic neuroinflammation mediated by senescent cells may exist following brain injury, especially traumatic. Senolytic therapy with intermittent D&Q was shown to be neuroprotective by reduction of SASP and subsequent attenuation of depressive symptoms and improved cognition.…”