The effect of female sex hormones on Hsp27 phosphorylation and histological changes in prefrontal cortex after tMCAO

Study on the action mechanism of Buyang Huanwu Decoction against ischemic stroke based on S1P/S1PR1/PI3K/Akt signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Ischemic stroke is a common and frequent clinical disease. Recent studies have demonstrated that sphingolipid plays an important role in the pathological process of ischemic stroke. PI3K-Akt is a classic protective signaling pathway of cerebral ischemic injury. After acting on the S1P receptor, S1P can activate the downstream PI3K/Akt signaling pathway and play an anti-cerebral ischemia role. Buyang Huanwu Decoction (BHD) is a traditional Chinese medicine formula used to treat ischemic stroke. However, the mechanisms of BHD on ischemic stroke remain unclear based on S1P/S1PR1/PI3K/Akt signaling pathway.

AIM OF THE STUDY

The present study is intended to investigate the action mechanism of BHD on ischemic stroke based on the S1P/S1PR1/PI3K/Akt signaling pathway from multiple perspectives.

MATERIALS AND METHODS

The BHD lyophilized product was prepared by vacuum freeze-drying method, of which the chemical composition was determined by UPLC-Q-TOF/MS. The mouse permanent middle cerebral artery occlusion (pMCAO) model was established by the suture-occluded method. Male KM mice were randomly divided into seven groups: sham group, model group, FTY720 (positive control) group, BHD group, BHD + W146 (selective S1PR1 inhibitor) group, SEW2871 (selective S1PR1 agonist) group, and Calycosin group. Each group was administered continuously for 14 days and evaluated with modified neurological severity score (mNSS) and cerebral infarct volume on the 1st, 4th, 7th, and 14th days. The SphK1, SphK2, S1PR1, PI3K, Akt, and p-Akt protein in the prefrontal lobe, hippocampus, and striatum was quantified by Western blot and immunohistochemical (IHC) experiment respectively. The qRT-PCR method was employed to evaluate SphK1, SphK2, and S1PR1 mRNA expression in the above tissue.

RESULTS

BHD and Calycosin both effectively improved mNSS scores with smaller infarct volumes. The SphK1 level in the prefrontal lobe, hippocampus, and striatum of mice in the BHD group was significantly lower, and SphK2, PI3K, and p-Akt in the hippocampus and striatum were significantly higher than those in the model group. BHD significantly decreased SphK1 mRNA expression in the prefrontal lobe, hippocampus, and striatum, and significantly up-regulated SphK2 mRNA and S1PR1 mRNA expression. Additionally, SphK1 protein expression levels of the prefrontal lobe, hippocampus, and striatum in the BHD group was significantly lower than model group, and SphK2, S1PR1, PI3K, Akt, and p-Akt protein expressions levels were increased obviously. Furthermore, SEW2871 can increase S1PR1 and Akt expression, and up-regulate SphK2 and S1PR1 mRNA expression. The effect of BHD on the expression of S1P/S1PR1/PI3K/Akt signaling pathway-related proteins and mRNA were weakened by BHD + W146.

CONCLUSION

BHD and Calycosin significantly improved the symptoms of neurological deficits in pMCAO mice, reduced the cerebral infarction volume, up-regulated SphK2 and S1PR1 mRNA levels, enhanced SphK2, S1PR1, PI3K, Akt, p-Akt protein expression of the prefrontal lobe, hippocampus and striatum, and down-regulated SphK1 mRNA and protein expression, which may be helpful to clarify the mechanism of BHD through S1P/S1PR1/PI3K/Akt signaling pathway to protect against cerebral ischemic injury.

Impact of Non-Invasive Physical Plasma on Heat Shock Protein Functionality in Eukaryotic Cells

Recently, biomedical research has increasingly investigated physical plasma as an innovative therapeutic approach with a number of therapeutic biomedical effects. It is known from radiation and chemotherapy that these applications can lead to the induction and activation of primarily cytoprotective heat shock proteins (HSP). HSP protect cells and tissues from physical, (bio)chemical, and physiological stress and, ultimately, along with other mechanisms, govern resistance and treatment failure. These mechanisms are well known and comparatively well studied in drug therapy. For therapies in the field of physical plasma medicine, however, extremely little data are available to date. In this review article, we provide an overview of the current studies on the interaction of physical plasma with the cellular HSP system.

Worsened Stroke Outcome in a Model of Preeclampsia is Associated With Poor Collateral Flow and Oxidative Stress

BACKGROUND

Preeclampsia increases the incidence of maternal stroke, a devastating condition that is on the rise. We investigated stroke outcome in a model of experimental preeclampsia with and without treatment with clinically relevant doses of magnesium sulfate (experimental preeclampsia+MgSO4) compared to normal late-pregnant and nonpregnant rats.

METHODS

Transient middle cerebral artery occlusion was used to induce focal stroke for either 1.5 or 3 hours. Infarct volume and hemorrhagic transformation were determined as measures of stroke outcome. Changes in core middle cerebral artery and collateral flow were measured by dual laser Doppler. The relationship between middle cerebral artery perfusion deficit and infarction was used as a measure of ischemic tolerance. Oxidative stress and endothelial dysfunction were measured by 3-nitrotyrosine and 8-isoprostane, in brain and serum, respectively.

RESULTS

Late-pregnant animals had robust collateral flow and greater ischemic tolerance of brain tissue, whereas experimental preeclampsia had greater infarction that was related to poor collateral flow, endothelial dysfunction, and oxidative stress. Importantly, pregnancy appeared preventative of hemorrhagic transformation as it occurred only in nonpregnant animals. MgSO4 did not provide benefit to experimental preeclampsia animals for infarction.

CONCLUSIONS

Stroke outcome was worse in a model of preeclampsia. As preeclampsia increases the risk of future stroke and cardiovascular disease, it is worth understanding the influence of preeclampsia on the material brain and factors that might potentiate injury both during the index pregnancy and years postpartum.

Research progress on the role of hormones in ischemic stroke

Ischemic stroke is a major cause of death and disability around the world. However, ischemic stroke treatment is currently limited, with a narrow therapeutic window and unsatisfactory post-treatment outcomes. Therefore, it is critical to investigate the pathophysiological mechanisms following ischemic stroke brain injury. Changes in the immunometabolism and endocrine system after ischemic stroke are important in understanding the pathophysiological mechanisms of cerebral ischemic injury. Hormones are biologically active substances produced by endocrine glands or endocrine cells that play an important role in the organism's growth, development, metabolism, reproduction, and aging. Hormone research in ischemic stroke has made very promising progress. Hormone levels fluctuate during an ischemic stroke. Hormones regulate neuronal plasticity, promote neurotrophic factor formation, reduce cell death, apoptosis, inflammation, excitotoxicity, oxidative and nitrative stress, and brain edema in ischemic stroke. In recent years, many studies have been done on the role of thyroid hormone, growth hormone, testosterone, prolactin, oxytocin, glucocorticoid, parathyroid hormone, and dopamine in ischemic stroke, but comprehensive reviews are scarce. This review focuses on the role of hormones in the pathophysiology of ischemic stroke and discusses the mechanisms involved, intending to provide a reference value for ischemic stroke treatment and prevention.

Calcitriol Pretreatment Attenuates Glutamate Neurotoxicity by Regulating NMDAR and CYP46A1 Gene Expression in Rats Subjected to Transient Middle Cerebral Artery Occlusion

Although the neuroprotective effects of calcitriol have been demonstrated in a variety of neurological diseases, such as stroke, the precise molecular mechanism has yet to be determined. This study aimed to investigate the possible role of calcitriol as a neuroprotective agent via CYP46A1 and glutamate receptors in a middle cerebral artery occlusion (MCAO) animal model. The MCAO technique was performed on adult male Wistar rats to induce focal cerebral ischemia for 1 hour followed by 23 hours of reperfusion. Calcitriol was given for 7 days prior to stroke induction. Sensorimotor functional tests were done 24 hours after ischemia/reperfusion, and infarct volume was estimated by tetrazolium chloride staining of brain sections. Gene expression of NR2A, NR2B, NR3B, and CYP46A1 was evaluated by RT-PCR followed by western blotting for NR3B protein. Our data revealed that calcitriol pretreatment reduced lesion volume and improved ischemic neurobehavioral parameters. Calcitriol therapy altered the expression of glutamate receptor and CYP46A1 genes. A possible molecular mechanism of calcitriol to reduce the severity and complications of ischemia may be through alterations of glutamate receptor and CYP46A1 gene expression.

Calcitriol ameliorates brain injury in the rat model of cerebral ischemia-reperfusion through Nrf2/HO-1 signalling axis: An in silico and in vivo study

OBJECTIVES

Calcitriol has been revealed to exert neuroprotective effects in ischemic stroke; however, its role and the underlying mechanisms in brain injury induced by ischemia are not well known. The purpose of this study was to determine the neuroprotective effects of calcitriol pretreatment and to assess the possible neuroprotective function of nuclear factor erythroid 2-related factor 2 (Nrf2)/ heme oxygenase-1 (HO-1) signalling pathway against brain ischemia/reperfusion (I/R) injury in the rat models which was followed by a bioinformatics approach.

METHODS

The experimental I/R model induction was performed in male Wistar rats for 1 h followed by 23 h reperfusion. Calcitriol was administered intraperitoneally for 7 days prior to stroke. Following ischemia induction 24 h later, neurobehavioral deficits and infarction volume were examined. Oxidative stress was assessed by measurement of malondialdehyde (MDA), nitric oxide (NO) and total antioxidant capacity (TAC). The protein and mRNA expression of HO-1 and Nrf2 were determined by western blot and reverse transcription polymerase chain reaction (RT-PCR), respectively. A molecular docking approach was applied to identify the interaction value of Keap1 with calcitriol.

RESULTS

Our data demonstrated that calcitriol significantly decreased infarction volume and ameliorated neurological deficits in brain I/R. MDA and NO levels were decreased and TAC level was elevated significantly after calcitriol pretreatment. Furthermore, calcitriol upregulated the expression of HO-1 and Nrf2 protein and mRNA in ischemic brain. Molecular modelling demonstrated that calcitriol could interact with the pocket of Keap1 by an appropriate binding energy.

CONCLUSIONS

The results indicate that calcitriol protects the brain against I/R injury. This effect may pass through inhibition of oxidative stress and Nrf2/HO-1 pathway activation and this may arise by interaction of Keap1 and calcitriol.

G-Protein-Coupled Receptors and Ischemic Stroke: a Focus on Molecular Function and Therapeutic Potential

In ischemic stroke, there is only one approved drug, tissue plasminogen activator, to be used in clinical conditions for thrombolysis. New neuroprotective therapies for ischemic stroke are desperately needed. Several targets and pathways have been shown to confer neuroprotective effects in ischemic stroke. G-protein-coupled receptors (GPCRs) are one of the most frequently targeted receptors for developing novel therapeutics for central nervous system disorders. GPCRs are a large family of cell surface receptors that response to a wide variety of extracellular stimuli. GPCRs are involved in a wide range of physiological and pathological processes. More than 90% of the identified non-sensory GPCRs are expressed in the brain, where they play important roles in regulating mood, pain, vision, immune responses, cognition, and synaptic transmission. There is also good evidence that GPCRs are implicated in the pathogenesis of stroke. This review narrates the pathophysiological role and possible targeted therapy of GPCRs in ischemic stroke.