Intraventricular Medium B Treatment Benefits an Ischemic Stroke Rodent Model via Enhancement of Neurogenesis and Anti-apoptosis

In vivo detection of poststroke cerebral cell proliferation in rodents and humans

OBJECTIVE

F-18-fluorothymidine (FLT) is a positron emission tomography (PET) tracer for imaging cell proliferation in vivo. We aimed to assess FLT uptake as a marker for cerebral cell proliferation in a rat model of ischemic stroke and patients with cerebral infarct, correlating with disease severity and outcomes.

METHODS

Cerebral FLT PET was performed in rats subjected to transient middle cerebral artery occlusion (MCAO) and patients with cerebral infarct. PET data were analyzed and expressed as average standardized uptake value ratios (SUVRs) using cerebellar cortex as reference. Infarct volume was analyzed by 2,3,5-triphenyltetrazolium chloride staining in rats and by magnetic resonance imaging in patients. Neurological function was assessed using modified Neurological Severity Score (mNSS) for rats and National Institutes of Health Stroke Scale (NIHSS) for patients.

RESULTS

Seven days post-MCAO, rats' FLT PET displayed higher SUVRs in the infarcted brain, declining gradually until Day 28. FLT-binding ratio (SUVR in the infarcted brain divided by that in contralateral side) correlated positively with stroke severity (p < 0.001), and to early mNSS decline in rats with mild to moderate stroke severity (p = 0.031). In 13 patients with cerebral infarct, FLT PET showed high SUVR in the infarcted regions. FLT-binding ratio correlated positively with infarct volume (p = 0.006). Age-adjusted initial NIHSS (p = 0.035) and early NIHSS decline (p = 0.076) showed significance or a trend toward positive correlation with the FLT-binding ratio.

INTERPRETATION

In vivo FLT PET detects poststroke cerebral cell proliferation, which is associated with stroke severity and/or outcomes in MCAO rats and patients with cerebral infarct.

Long noncoding RNA ANRIL knockdown attenuates neuroinflammation following ischemic stroke via suppressing the expression of NF-κB in vitro and in vivo

OBJECTIVE

Increasing evidence suggests that long-noncoding RNAs can exert neuroprotective effects in cerebral ischemia-reperfusion injury. Levels of the long noncoding RNA ANRIL (ANRIL) are reportedly altered in ischemic stroke (IS) patients, but its role in IS requires further clarification. This study was designed to explore the mechanistic function of ANRIL in IS.

METHODS

In vitro, HT22 cells was treated with an oxygen-glucose deprivation/reperfusion (OGD/R). In vivo, brain ischemia/reperfusion was induced by 60-minute transient middle cerebral artery occlusion/reperfusion (MCAO/R) IS model in C57/BL6 mice. Additionally, cells were transfected with si-ANRIL, pcDNA3.1-ANRIL, pcDNA3.1-NF-κB, or appropriate negative controls, and si-ANRIL and pcDNA3.1-NF-κB were administered into the lateral ventricles in MCAO/R model mice. Cell viability and apoptosis were detected via MTT and flow cytometry assays. mRNA and protein expression of NF-κB were detected via qRT-PCR and Western blotting. IL-1β, IL-6, TNF-a, and iNOS levels were detected via ELISA. In addition, infarcted area and neuronal injury were evaluated via TTC, Nissl, and immunofluorescent staining.

RESULTS

We found that ANRIL knockdown increased cell viability and reduced apoptosis in vitro. Additionally, we found that ANRIL knockdown decreased p-P65, P65, IL-1β, IL-6, TNF-a, and iNOS levels, whereas these effects were reversed by NF-κB overexpression both in vitro and in vivo.

CONCLUSION

our results suggest that ANRIL knockdown attenuates neuroinflammation by suppressing the expression of NF-κB both in vitro and vivo model of IS, sugguesting that ANRIL might be a potentially viable therapeutictarget to diminish neuroinflammation in IS patients.

Oxytocin Receptor Signaling in Vascular Function and Stroke

The oxytocin receptor (OXTR) is a G protein-coupled receptor with a diverse repertoire of intracellular signaling pathways, which are activated in response to binding oxytocin (OXT) and a similar nonapeptide, vasopressin. This review summarizes the cell and molecular biology of the OXTR and its downstream signaling cascades, particularly focusing on the vasoactive functions of OXTR signaling in humans and animal models, as well as the clinical applications of OXTR targeting cerebrovascular accidents.

TRIM62 knockout protects against cerebral ischemic injury in mice by suppressing NLRP3-regulated neuroinflammation

Cerebral stroke is a leading global cause for mortality and disability. However, its pathogenesis is still unclear. Most tripartite motif (TRIM) family proteins, including TRIM62, have E3 ubiquitin ligase activities, and have multiple functions in regulating cellular processes. Nevertheless, the effects of TRIM62 on cerebral stroke still remain vague. Here, we reported that TRIM62 expression was markedly up-regulated in oxygen and glucose deprivation (OGD)-treated microglial cells. After cerebral ischemia, significantly elevated expression of TRIM62 was detected in peri-infarct area of wild type (WT) mice. The TRIM62 knockout (KO) mice exhibited alleviated apoptosis and neuroinflammation in the ischemic brain, eventually attenuating the stroke outcomes. Both in vitro and in vivo studies showed that nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome was dramatically activated in cerebral ischemia/reperfusion (I/R) conditions, while being ameliorated in TRIM62-KO mice, contributing to the suppression of neuroinflammatory response. Importantly, the in vitro experiments showed that OGD could induce the K63-ubiquitination of TRIM62 and the interaction between TRIM62 and NLRP3. In addition, adenovirus-regulated TRIM62 over-expression promoted the NLRP3 and nuclear factor κB (NF-κB) signaling, along with elevated interleukin-1β (IL-1β) and IL-18 transcriptional activities. Together, our results demonstrated that TRIM62 suppression was strongly protective in ischemic stroke through inhibiting NLRP3-regulated neuroinflammation.