Regenerative repair of Pifithrin-α in cerebral ischemia via VEGF dependent manner

A systematic review and in silico analysis of studies investigating the ischaemic penumbra proteome in animal models of experimental stroke

Ischaemic stroke results in the formation of a cerebral infarction bordered by an ischaemic penumbra. Characterising the proteins within the ischaemic penumbra may identify neuro-protective targets and novel circulating markers to improve patient care. This review assessed data from studies using proteomic platforms to compare ischaemic penumbra tissues to controls following experimental stroke in animal models. Proteins reported to differ significantly between penumbra and control tissues were analysed in silico to identify protein-protein interactions and over-represented pathways. Sixteen studies using rat (n = 12), mouse (n = 2) or primate (n = 2) models were included. Heterogeneity in the design of the studies and definition of the penumbra were observed. Analyses showed high abundance of p53 in the penumbra within 24 hours of permanent ischaemic stroke and was implicated in driving apoptosis, cell cycle progression, and ATM- MAPK- and p53- signalling. Between 1 and 7 days after stroke there were changes in the abundance of proteins involved in the complement and coagulation pathways. Favourable recovery 1 month after stroke was associated with an increase in the abundance of proteins involved in wound healing. Poor recovery was associated with increases in prostaglandin signalling. Findings suggest that p53 may be a target for novel therapeutics for ischaemic stroke.

PFT-α protects the blood-brain barrier through the Wnt/β-catenin pathway after acute ischemic stroke

The dysfunction of blood-brain barrier (BBB) plays a pivotal role in brain injury and subsequent neurological deficits of ischemic stroke. The current study aimed to examine the potential correlation between p53 inhibition and the neuroprotective effect of on the BBB. Rat middle cerebral artery occlusion and reperfusion model (MCAO/R) and oxygen-glucose deprivation/re-oxygenation model (OGD/R) were employed to simulate cerebral ischemia-reperfusion (CI/R) injury occurrence in vivo and in vitro. mNSS and TTC staining were applied to evaluate neurological deficits and brain infarct volumes. Evans blue (EB) staining was carried out to examine the permeability of BBB. RT-qPCR and Western blot to examine the mRNA and protein levels. Cell viabilities were detected by CCK-8. Flow cytometry and ELISA assay were employed to examine apoptosis and neuroinflammation levels. TEER value and sodium fluorescein were carried out to explore the permeability of HBMEC cells. PFT-α inhibited P53 and promoted the expression of β-catenin and cyclin D1, which were reversed by DKK1. PFT-α inhibited neurological deficits, brain infarct volume, neuroinflammation, apoptosis, and BBB integrity than the MCAO/R rats; however, this inhibition was reversed by DKK1. PFT-α promoted OGD/R-induced cell viability in NSCs, and suppressed inflammation and apoptosis, but DKK1 weakened the effect of PFT-α. PFT-α increased OGD/R-induced TEER values in cerebrovascular endothelial cells, inhibited sodium fluorescein permeability, and increased the mRNA levels of tight junction protein, but they were all attenuated by DKK1. PFT-α protects the BBB after acute ischemic stroke via the Wnt/β-catenin pathway, which in turn improves neurological function.

Potential enhancement of post-stroke angiogenic response by targeting the oligomeric aggregation of p53 protein

Tumor suppressor gene p53 and its aggregate have been found to be involved in many angiogenesis-related pathways. We explored the possible p53 aggregation formation mechanisms commonly occur after ischemic stroke, such as hypoxia and the presence of reactive oxygen species (ROS). The angiogenic pathways involving p53 mainly occur in nucleus or cytoplasm, with one exception that occurs in mitochondria. Considering the high mitochondrial density in brain and endothelial cells, we proposed that the cyclophilin D (CypD)-dependent vascular endothelial cell (VECs) necrosis pathway occurring in the mitochondria is one of the major factors that affects angiogenesis. Hence, targeting p53 aggregation, a key intermediate in the pathway, could be an alternative therapeutic target for post-stroke management.

Angiogenesis after ischemic stroke

Owing to its high disability and mortality rates, stroke has been the second leading cause of death worldwide. Since the pathological mechanisms of stroke are not fully understood, there are few clinical treatment strategies available with an exception of tissue plasminogen activator (tPA), the only FDA-approved drug for the treatment of ischemic stroke. Angiogenesis is an important protective mechanism that promotes neural regeneration and functional recovery during the pathophysiological process of stroke. Thus, inducing angiogenesis in the peri-infarct area could effectively improve hemodynamics, and promote vascular remodeling and recovery of neurovascular function after ischemic stroke. In this review, we summarize the cellular and molecular mechanisms affecting angiogenesis after cerebral ischemia registered in PubMed, and provide pro-angiogenic strategies for exploring the treatment of ischemic stroke, including endothelial progenitor cells, mesenchymal stem cells, growth factors, cytokines, non-coding RNAs, etc.

Attenuation of Acute Intracerebral Hemorrhage-Induced Microglial Activation and Neuronal Death Mediated by the Blockade of Metabotropic Glutamate Receptor 5 In Vivo

The activation of microglia in response to intracerebral hemorrhagic stroke is one of the principal components of the progression of this disease. It results in the formation of pro-inflammatory cytokines that lead to neuronal death, a structural deterioration that, in turn interferes with functional recovery. Metabotropic glutamate receptor 5 (mGluR5) is highly expressed in reactive microglia and is involved in the pathological processes of brain disorders, but its role in intracerebral hemorrhage (ICH) remains unknown. We hypothesized that mGluR5 regulates microglial activation and ICH maintenance. In this study, collagenase-induced ICH mice received a single intraperitoneal injection of the mGluR5 antagonist-, MTEP, or vehicle 2 h after injury. We found that acute ICH upregulated mGluR5 and microglial activation. mGluR5 was highly localized in reactive microglia in the peri-hematomal cortex and striatum on days 3 and 7 post-ICH. The MTEP-mediated pharmacological inhibition of mGluR5 in vivo resulted in the substantial attenuation of acute microglial activation and IL-6, and TNF-α release. We also showed that the blockade of mGluR5 markedly reduced cell apoptosis, and neurodegeneration and markedly elevated neuroprotection. Furthermore, the MTEP-mediated inhibition of mGluR5 significantly reduced the lesion volume and improved functional recovery. Taken together, our results demonstrate that ICH injury enhances mGluR5 expression in the acute and subacute stages and that mGluR5 is highly localized in reactive microglia. The blockade of mGluR5 reduces ICH-induced acute microglial activation, provides neuroprotection and promotes neurofunctional recovery after ICH. The inhibition of mGluR5 may be a relevant therapeutic target for intracerebral hemorrhagic stroke.

Pifithrin-α alters p53 post-translational modifications pattern and differentially inhibits p53 target genes

Pifithrin-α (PFT-α) is a small molecule which has been widely used as a specific inhibitor of p53 transcription activity. However, its molecular mechanism of action remains unclear. PFT-α has also been described to display potent p53-independent activity in cells. In this study, we addressed the mechanism of action of PFT-α. We found that PFT-α failed to prevent the effects of Mdm2 inhibitor Nutlin-3 on cell cycle and apoptosis in several cancer cell lines. However, PFT-α rescued normal primary fibroblasts from growth inhibition by Nutlin-3. PFT-α displayed a very limited effect on p53-dependent transcription upon its activation by Nutlin-3. Moreover, PFT-α inhibitory effect on transcription was highly dependent on the nature of the p53 target gene. PFT-α attenuated post-translational modifications of p53 without affecting total p53 protein level. Finally, we found that PFT-α can decrease the level of intracellular reactive oxygen species through activation of an aryl hydrocarbon receptor (AHR)-Nrf2 axis in a p53-independent manner. In conclusion, PFT-α inhibits only some aspects of p53 function, therefore it should be used with extreme caution to study p53-dependent processes.

Fangchinoline Ameliorates the Expressions of Angiogenic Molecule in Cerebral Ischemia Induced Neuronal Degeneration in Neonatal Rats

Background

Present investigation evaluates the beneficial effect of fangchinoline on cerebral ischemia induced neuronal degeneration in neonatal rats and also postulates the possible mechanism of its action.

Methodology

Cerebral ischemia was produced by the ligation of right common carotid artery in neonatal rats on postnatal day 5 (P5) and further pups were treated with fangchinoline 3, 10 and 30 mg/kg, i.p. for the period of 3 days. Effect of fangchinoline was estimated by determining the brain injury and enzyme linked immunosorbent assay (ELISA) method was used for the estimation of pro-inflammatory mediators and markers of oxidative stress in the cerebral tissues of neonatal rats. Moreover western blot assay and histopathology study was also performed on the brain tissue.

Results

Result of this investigation reveals that the percentage of brain injury significantly reduces and enhancement of myelin basic protein in the cerebral tissues of fangchinoline than ischemic group. Treatment with fangchinoline attenuates the altered level of proinflammatory mediators and markers of oxidative stress in the cerebral tissue of cerebral ischemia induced neuronal injury neonatal rats. Moreover expressions of inducible nitric oxide synthtase (iNOS), vascular endothelial growth factor (VEGF), p53 and nuclear receptor factor-2 (Nrf2) in the brain tissue attenuated by fangchinoline treated group.

Conclusion

In conclusion, fangchinoline ameliorates the cerebral ischemia induced neuronal injury in neonatal rats by enhancing angiogenesis molecules.

Cerebral ischemia and neuroregeneration

Cerebral ischemia is one of the leading causes of morbidity and mortality worldwide. Although stroke (a form of cerebral ischemia)-related costs are expected to reach 240.67 billion dollars by 2030, options for treatment against cerebral ischemia/stroke are limited. All therapies except anti-thrombolytics (i.e., tissue plasminogen activator) and hypothermia have failed to reduce neuronal injury, neurological deficits, and mortality rates following cerebral ischemia, which suggests that development of novel therapies against stroke/cerebral ischemia are urgently needed. Here, we discuss the possible mechanism(s) underlying cerebral ischemia-induced brain injury, as well as current and future novel therapies (i.e., growth factors, nicotinamide adenine dinucleotide, melatonin, resveratrol, protein kinase C isozymes, pifithrin, hypothermia, fatty acids, sympathoplegic drugs, and stem cells) as it relates to cerebral ischemia.

Long-term Intake of Pasta Containing Barley (1-3)Beta-D-Glucan Increases Neovascularization-mediated Cardioprotection through Endothelial Upregulation of Vascular Endothelial Growth Factor and Parkin

Barley (1-3)β-D-Glucan (BBG) enhances angiogenesis. Since pasta is very effective in providing a BBG-enriched diet, we hypothesized that the intake of pasta containing 3% BBG (P-BBG) induces neovascularization-mediated cardioprotection. Healthy adult male C57BL/6 mice fed P-BBG (n = 15) or wheat pasta (Control, n = 15) for five-weeks showed normal glucose tolerance and cardiac function. With a food intake similar to the Control, P-BBG mice showed a 109% survival rate (P < 0.01 vs. Control) after cardiac ischemia (30 min)/reperfusion (60 min) injury. Left ventricular (LV) anion superoxide production and infarct size in P-BBG mice were reduced by 62 and 35% (P < 0.0001 vs. Control), respectively. The capillary and arteriolar density of P-BBG hearts were respectively increased by 12 and 18% (P < 0.05 vs. Control). Compared to the Control group, the VEGF expression in P-BBG hearts was increased by 87.7% (P < 0.05); while, the p53 and Parkin expression was significantly increased by 125% and cleaved caspase-3 levels were reduced by 33% in P-BBG mice. In vitro, BBG was required to induce VEGF, p53 and Parkin expression in human umbelical vascular endothelial cells. Moreover, the BBG-induced Parkin expression was not affected by pifithrin-α (10 uM/7days), a p53 inhibitor. In conclusion, long-term dietary supplementation with P-BBG confers post-ischemic cardioprotection through endothelial upregulation of VEGF and Parkin.

Effect of Trp53 gene deficiency on brain injury after neonatal hypoxia-ischemia

Hypoxia-ischemia (HI) can result in permanent life-long injuries such as motor and cognitive deficits. In response to cellular stressors such as hypoxia, tumor suppressor protein p53 is activated, potently initiating apoptosis and promoting Bax-dependent mitochondrial outer membrane permeabilization. The aim of this study was to investigate the effect of Trp53 genetic inhibition on injury development in the immature brain following HI. HI (50 min or 60 min) was induced at postnatal day 9 (PND9) in Trp53 heterozygote (het) and wild type (WT) mice. Utilizing Cre-LoxP technology, CaMK2α-Cre mice were bred with Trp53-Lox mice, resulting in knockdown of Trp53 in CaMK2α neurons. HI was induced at PND12 (50 min) and PND28 (40 min). Extent of brain injury was assessed 7 days following HI. Following 50 min HI at PND9, Trp53 het mice showed protection in the posterior hippocampus and thalamus. No difference was seen between WT or Trp53 het mice following a severe, 60 min HI. Cre-Lox mice that were subjected to HI at PND12 showed no difference in injury, however we determined that neuronal specific CaMK2α-Cre recombinase activity was strongly expressed by PND28. Concomitantly, Trp53 was reduced at 6 weeks of age in KO-Lox Trp53 mice. Cre-Lox mice subjected to HI at PND28 showed no significant difference in brain injury. These data suggest that p53 has a limited contribution to the development of injury in the immature/juvenile brain following HI. Further studies are required to determine the effect of p53 on downstream targets.

The protective effect of PFTα on alcohol-induced osteonecrosis of the femoral head

Epidemiologic studies have shown alcohol plays a pivotal role in the development of osteonecrosis of the femoral head (ONFH). The aim of this study was to explore the underlying mechanism of alcohol-induced ONFH and the protective effect of pifithrin-α (PFTα). In vitro, we found ethanol treatment significantly activated p53, suppressed Wnt/β-catenin signaling and inhibited osteogenic-related proteins. Furthermore, by separating the cytoplasmic and nuclear proteins, we found ethanol inhibited osteogenesis by impairing the accumulation of β-catenin in both the cytoplasm and nucleus in human bone mesenchymal stem cells (hBMSCs), which resulted from activating glycogen synthase kinase-3β (GSK-3β). Therefore, PFTα, a p53 inhibitor, was introduced in this study to block the ethanol-triggered activation of p53 in hBMSCs and alcohol-induced ONFH in a rat model. In vivo, we established alcohol-induced ONFH in rats and investigated the protective effect of PFTα. Hematoxylin & eosin (H&E) staining combined with TdT-mediated dUTP nick end labeling (TUNEL), cleaved caspase-3 immunohistochemical staining, and micro-CT images revealed substantial ONFH in the alcohol-administered rats, whereas significantly less osteonecrosis developed in the rats injected with PFTα. Osteogenic-related proteins, including osteocalcin, osteopontin and collagen I, were significantly decreased in the alcohol-administered rats, whereas these results were reversed in the PFTα-injected rats. Fluorochrome labeling similarly showed that alcohol significantly reduced the osteogenic activity in the rat femoral head, which was blocked by the injection of PFTα. In conclusion, PFTα had an antagonistic effect against the effects of ethanol on hBMSCs and could be a clinical strategy to prevent the development of alcohol-induced ONFH.

Mechanisms of Parkinson's disease-related proteins in mediating secondary brain damage after cerebral ischemia

Both Parkinson's disease (PD) and stroke are debilitating conditions that result in neuronal death and loss of neurological functions. These two conditions predominantly affect aging populations with the deterioration of the quality of life for the patients themselves and a tremendous burden to families. While the neurodegeneration and symptomology of PD develop chronically over the years, post-stroke neuronal death and dysfunction develop rapidly in days. Despite the discrepancy in the pathophysiological time frame and severity, both conditions share common molecular mechanisms that include oxidative stress, mitochondrial dysfunction, inflammation, endoplasmic reticulum stress, and activation of various cell death pathways (apoptosis/necrosis/autophagy) that synergistically modulate the neuronal death. Emerging evidence indicates that several proteins associated with early-onset familial PD play critical roles in mediating the neuronal death. Importantly, mutations in the genes encoding Parkin, PTEN-induced putative kinase 1 and DJ-1 mediate autosomal recessive forms of PD, whereas mutations in the genes encoding leucine-rich repeat kinase 2 and α-synuclein are responsible for autosomal dominant PD. This review discusses the significance of these proteins with the emphasis on the role of α-synuclein in mediating post-ischemic brain damage.

MgAl layered double hydroxide/chitosan porous scaffolds loaded with PFTα to promote bone regeneration

Poor bone formation remains a key risk factor associated with acellular scaffolds that occurs in some bone defects, particularly in patients with metabolic bone disorders and local osteoporosis. We herein fabricated for the first time layered double hydroxide-chitosan porous scaffolds loaded with PFTα (LDH-CS-PFTα scaffolds) as therapeutic bone scaffolds for the controlled release of PFTα to enhance stem cell osteogenic differentiation and bone regeneration. The LDH-CS scaffolds had three-dimensional interconnected macropores, and plate-like LDH nanoparticles were uniformly dispersed within or on the CS films. The LDH-CS scaffolds exhibited appropriate PFTα drug delivery due to hydrogen bonding among LDH, CS and PFTα. In vitro functional studies demonstrated that the PFTα molecules exhibited potent ability to induce osteogenesis of hBMSCs via the GSK3β/β-catenin pathway, and the LDH-CS-PFTα scaffolds significantly enhanced the osteogenic differentiation of hBMSCs. In vivo studies revealed significantly increased repair and regeneration of bone tissue in cranial defect model rats compared to control rats at 12 weeks post-implantation. In conclusion, the LDH-CS-PFTα scaffolds exhibited excellent osteogenic differentiation and bone regeneration capability and hold great potential for applications in defined local bone regeneration.