Caspase-3 modulates regenerative response after stroke

Exploring caspase functions in mouse models

Caspases are enzymes with protease activity. Despite being known for more than three decades, caspase investigation still yields surprising and fascinating information. Initially associated with cell death and inflammation, their functions have gradually been revealed to extend beyond, targeting pathways such as cell proliferation, migration, and differentiation. These processes are also associated with disease mechanisms, positioning caspases as potential targets for numerous pathologies including inflammatory, neurological, metabolic, or oncological conditions. While in vitro studies play a crucial role in elucidating molecular pathways, they lack the context of the body's complexity. Therefore, laboratory animals are an indispensable part of successfully understanding and applying caspase networks. This paper aims to summarize and discuss recent knowledge, understanding, and challenges in caspase knock-out mice.

Serum Caspase-3 Levels as a Predictive Molecular Biomarker for Acute Ischemic Stroke

Caspases are key players in the apoptotic process and have been found to contribute to the pathogenesis of a variety of diseases, including neurological disorders such as ischemic stroke. This study aimed to investigate the serum levels of Caspase-3 in patients with acute ischemic stroke (AIS) and in control patients without ischemic events. Moreover, we explored any potential associations with the clinical outcomes of AIS. We enrolled 69 consecutive patients with clinical signs and symptoms of AIS in the presence of a negative CT scan who presented themselves at the Clinical Neurological Department from the Emergency Clinical Hospital of Galati within the first 24 h of symptom onset. The control group comprised 68 patients without cerebral ischemic pathologies. A comparison of the two groups showed significantly higher levels of caspase-3 at 24 and 48 h after hospital admission. No significant associations between caspase-3 levels and clinical features of AIS were seen. However, in a subgroup analysis conducted on patients with moderate/severe and severe stroke, lower levels of caspase-3 were associated with early mortality. Caspase-3 levels did not directly correlate with AIS severity or prognosis when considering all AIS patients. In patients with moderate to severe National Institute of Health Stroke Scale (NIHSS) scores, caspase-3 might be a prognostic indicator of early death. Further studies are required to confirm these results and further explore the mechanisms behind these findings.

Bioinformatics analysis and experimental validation revealed that Paeoniflorigenone effectively mitigates cerebral ischemic stroke by suppressing oxidative stress and inflammation

Inflammation and oxidative stress are becoming more recognized as risk factors for ischemic stroke. Paeoniflorigenone (PA) has diverse pharmacological effects that include anti-inflammatory and antioxidant properties. However, the specific mechanisms by which PA affects cerebral ischemic stroke have not been studied. Our objective was to investigate the potential targets and mechanisms of PA in preventing cerebral ischemic stroke. We obtained the potential targets of PA from the SwissTargetPrediction, Super-PRED, and SEA Search Server databases. The GSE97537 dataset was utilized to identify gene targets related to ischemic stroke. The overlapping targets were imported into the STRING database to construct a protein-protein interaction network, and enrichment analyses were conducted using R software. Rats were pretreated with PA for three weeks before undergoing MCAO and reperfusion. H&E staining, ELISA, and qRT-PCR analyses were then performed to explore the potential mechanisms of PA. In the study, we identified 439 potential targets for PA and 1206 potential targets for ischemic stroke. Out of these, there were 71 common targets, which were found to be primarily associated with pathways related to oxidative stress and inflammation. The results from animal experiments showed that PA was able to improve nerve function and reduce inflammatory cytokines and oxidative stress in the MCAO-induced ischemic stroke model. Additionally, the expression of core genes in the MCAO + HPA group was significantly lower compared to the MCAO group. Our study revealed that the potential mechanisms by which PA prevents ischemic stroke involve oxidative stress and inflammation. These findings provide important theoretical guidance for the clinical use of PA in preventing and managing ischemic stroke.

Cellular stress management by caspases

Cellular stress plays a pivotal role in the onset of numerous human diseases. Consequently, the removal of dysfunctional cells, which undergo excessive stress-induced damage via various cell death pathways, including apoptosis, is essential for maintaining organ integrity and function. The evolutionarily conserved family of cysteine-aspartic-proteases, known as caspases, has been a key player in orchestrating apoptosis. However, recent research has unveiled the capability of these enzymes to govern fundamental cellular processes without triggering cell death. Remarkably, some of these non-lethal functions of caspases may contribute to restoring cellular equilibrium in stressed cells. This manuscript discusses how caspases can function as cellular stress managers and their potential impact on human health and disease. Additionally, it sheds light on the limitations of caspase-based therapies, given our still incomplete understanding of the biology of these enzymes, particularly in non-apoptotic contexts.

Endogenous Neural Stem Cell-induced Neurogenesis after Ischemic Stroke: Processes for Brain Repair and Perspectives

Ischemic stroke is a very common cerebrovascular accident that occurred in adults and causes higher risk of neural deficits. After ischemic stroke, patients are often left with severe neurological deficits. Therapeutic strategies for ischemic stroke might mitigate neuronal loss due to delayed neural cell death in the penumbra or seek to replace dead neural cells in the ischemic core. Currently, stem cell therapy is the most promising approach for inducing neurogenesis for neural repair after ischemic stroke. Stem cell treatments include transplantation of exogenous stem cells but also stimulating endogenous neural stem cells (NSCs) proliferation and differentiation into neural cells. In this review, we will discuss endogenous NSCs-induced neurogenesis after ischemic stroke and provide perspectives for the therapeutic effects of endogenous NSCs in ischemic stroke. Our review would inform future therapeutic development not only for patients with ischemic stroke but also with other neurological deficits.

New Insights of Early Brain Injury after Subarachnoid Hemorrhage: A Focus on the Caspase Family

Spontaneous subarachnoid hemorrhage (SAH), primarily caused by ruptured intracranial aneurysms, remains a prominent clinical challenge with a high rate of mortality and morbidity worldwide. Accumulating clinical trials aiming at the prevention of cerebral vasospasm (CVS) have failed to improve the clinical outcome of patients with SAH. Therefore, a growing number of studies have shifted focus to the pathophysiological changes that occur during the periods of early brain injury (EBI). New pharmacological agents aiming to alleviate EBI have become a promising direction to improve outcomes after SAH. Caspases belong to a family of cysteine proteases with diverse functions involved in maintaining metabolism, autophagy, tissue differentiation, regeneration, and neural development. Increasing evidence shows that caspases play a critical role in brain pathology after SAH. Therefore, caspase regulation could be a potential target for SAH treatment. Herein, we provide an overview pertaining to the current knowledge on the role of caspases in EBI after SAH, and we discuss the promising therapeutic value of caspase-related agents after SAH.

Advanced molecular therapies for neurological diseases: focus on stroke, alzheimer's disease, and parkinson's disease

Neurological diseases (NDs) are one of the leading causes of disability and the second leading cause of death globally. Among these stroke, Alzheimer's disease (AD), and Parkinson's disease (PD) are the most common NDs. A rise in the absolute number of individuals affected with these diseases indicates that the current treatment strategies in management and prevention of these debilitating diseases are not effective sufficiently. Therefore, novel treatment strategies are being explored to cure these diseases by addressing the causative mechanisms at the molecular level. Advanced therapies like gene therapy (gene editing and gene silencing) and stem cell therapies aim to cure diseases by gene editing, gene silencing and tissue regeneration, respectively. Gene editing results in the deletion of the aberrant gene or insertion of the corrected gene which can be executed using the CRISPR/Cas gene editing tool a promising treatment strategy being explored for many other prevalent diseases. Gene silencing using siRNA silences the gene by inhibiting protein translation, thereby silencing its expression. Stem cell therapy aims to regenerate damaged cells or tissues because of their ability to divide into any type of cell in the human body. Among these approaches, gene editing and gene silencing have currently been applied in vitro and to animal models, while stem cell therapy has reached the clinical trial stage for the treatment of NDs. The current status of these strategies suggests a promising outcome in their clinical translation.

Drowning versus postmortem submersion: Biochemical and histopathological examination and estimation of postmortem intervals (an experimental study)

Estimation of the postmortem interval (PMI) is a very essential task for forensic experts especially in criminal cases. drowning is still the most difficult tasks for forensic pathologists to be diagnosed and differentiated from a body disposed of in water following death especially after long post-mortem period. The objective of this study was to estimate the PMI in drowning in comparison to postmortem submersion using mRNA expression of AQP1 in addition to histological and immunohistochemical examination of caspase-3 in the adrenal and thyroid glands of adult albino rats. Adult albino rats were divided into 2 groups; group A (drowning) and group B (post-mortem submersion). Thyroid and adrenal glands were examined at different PMI. The results revealed significant differences at AQP1 levels between drowning and postmortem submersion at different PMI. Histological changes and caspase-3 expression immunologically in both glands were helpful.

Evaluation of the therapeutic effects of calcium dobesilate in sciatic nerve crush injury in rats

INTRODUCTION

Proinflammatory cytokines released from nerve endings and surrounding injured tissue after nerve damage can prolong the inflammation process, delay nerve healing or result in poor quality nerve healing. In this case, due to the loss of function in the muscles innervated by the damaged nerve, the patient may have neurological and functional difficulties which may reduce the patient's quality of life and create an economic burden. Although the attempts of many pharmacological agents to heal crush injury of peripheral nerves have been recorded in literature, a drug that can provide adequate recovery of the crushed nerve and can be applied in daily life has not been defined as yet. This study aimed to assess the effects of calcium dobesilate on sciatic nerve crush injury in a rat model.

METHODS

A total of 26 male Wistar albino rats were separated into four groups as follows: CONTROL group (healthy subjects, n=6); SHAM group (crush injury was created, n=6); MP group (after created crush injury, methylprednisolone was administered, n=7); and CAD group (after created crush injury, calcium dobesilate was administered, n=7). A crush injury was created, then the electrophysiological findings and sciatic nerve functional index (SFI) were recorded before euthanasia. After the euthanasia of all the rats, samples of the crushed nerve and gastrocnemius muscle were evaluated histopathologically, immunohistochemically, and biochemically.

RESULTS

Both pharmacological agents were histopathologically effective in axon regeneration and repair. Calcium dobesilate did not preserve total muscle mass but was seen to prevent atrophy microscopically. Immunohistochemistry and biochemistry results showed that calcium dobesilate and methylprednisolone had anti-inflammatory, anti-oxidant, anti-apoptotic, and anti-autophagic activity in the crushed sciatic nerve. Neither calcium dobesilate nor methylprednisolone improved the nerve conductance level. SFI values obtained on day 30 from the CAD group were numerically closer to the values of the healthy animals but not at a statistically significant level.

CONCLUSION

The study results demonstrated that calcium dobesilate could suppress inflammatory processes and provide histopathological and functional improvements in the injured nerve in rats. Therefore, further clinical studies are recommended to investigate in detail the therapeutic effects of calcium dobesilate on peripheral nerve crush injury.

The Combination of Individual Herb of Mi-Jian-Chang-Pu Formula Exerts a Synergistic Effect in the Treatment of Ischemic Stroke in Rats

Mi-Jian-Chang-Pu formula (MJCPF), composed of Crocus sativus L. and Acorus tatarinowii Schott, is a well-known TCM for treatment of hemiplegia, facial paralysis as well as language dysfunction caused by stroke both in ancient and modern times. By using pharmacodynamics, pharmacokinetics, and metabolomics, our present study discusses whether the combination of individual herbs or major active components of MJCPF possess synergistic neuroprotective effects against ischemic stroke (IS). 108 adult male Sprague-Dawley rats were randomly and equally divided into 9 groups, including sham group (N, vehicle), middle cerebral artery occlusion (MCAO) model group (M, vehicle), positive group (P, 36 mg/kg/day nimodipine), crocin I (A1, 40 mg/kg/day), β-asarone (B1, 15 mg/kg/day), crocin I + β-asarone (A1B1, 55 mg/kg/day), C. sativus (A, 580 mg/kg/day), A. tatarinowii (B, 480 mg/kg/day), and C. sativus + A. tatarinowii, also named MJCPF (AB, 1060 mg/kg/day) groups. All drugs were orally administered to rats once a day for 14 consecutive days. Neurological deficit score, cerebral infarct volume, body weight change, TTC, HE and IHC staining, behavioral evaluation, metabolic profiles, and pharmacokinetic parameters were determined. MCAO led to severe brain damage including large infarct volume, more severe brain tissue injury, and worse neurological function as compared to the sham rats. All treatment groups showed a significant neuroprotective effect on MCAO rats. Furthermore, the pharmacodynamics' results demonstrated that MJCPF had a synergistic effect evidenced by small infarct volume, more regular arrangement of neuronal cells, and more improved neural function, and the levels of inflammatory factors were closer to normality. A total of 53 differential metabolites between MCAO and sham groups were screened by integration of serum and brain metabolisms, all of which were restored at varying degrees in treatment. PCA and PLS-DA analysis showed that the levels of differential metabolites treated with MJCPF were closer to the sham group than the individual herb and single compound alone or A1B1 combination. The pharmacokinetic parameters further verified the above results that MJCPF could synergistically promote drug absorption greater than others. Our integrated pharmacodynamics, metabolomics, and pharmacokinetic approach reveals the synergistic effect of MJCPF on treatment of IS, which powerfully contribute to the understanding of scientific connotation of TMC formula.

Probiotic as a Potential Gut Microbiome Modifier for Stroke Treatment: A Systematic Scoping Review of In Vitro and In Vivo Studies

BACKGROUND

Pharmacologic and non-pharmacologic treatments for stroke are essential but can be costly or harmful, whereas probiotics are a promising alternative. This scoping review aimed to synthesize the in vitro and in vivo evidence of probiotics on stroke-related neurological, biochemical, and histochemical outcomes.

METHODS

A systematic review was conducted in PubMed, Embase, and Cochrane Central Register of Clinical Trials (CENTRAL) up to 7 May 2021. Titles and abstracts were screened and assessed by two independent reviewers. The initial screening criteria aimed to include studies using probiotics, prebiotics, and symbiotics both in vitro and in vivo for the prevention and/or treatment of stroke.

RESULTS

Of 6293 articles, 4990 passed the initial screen after excluding duplication articles, of which 36 theme-related full texts were assessed and 13 were included in this review. No in vitro studies passed the criteria to be included in this review. Probiotics can ameliorate neurological deficits and show their anti-inflammation and anti-oxidative properties. Decreased loss of cerebral volume and inhibition of neuronal apoptosis were revealed in histopathological evidence.

CONCLUSIONS

There are potential cognitive benefits of probiotic supplementation, especially among animal models, on decreasing cerebral volume, increasing neurological score, and decreasing the inflammatory response. However, further investigation is needed to validate these conclusions in various populations.

Altered expression of vesicular glutamate transporter-2 and cleaved caspase-3 in the locus coeruleus of nerve-injured rats

Neuropathic pain is a debilitating chronic condition provoked by a lesion in the nervous system and it induces functional alterations to the noradrenergic locus coeruleus (LC), affecting distinct dimensions of pain, like sensorial hypersensitivity, pain-induced depression, and anxiety. However, the neurobiological changes induced by nerve damage in the LC remain unclear. Here, we analyzed excitatory and inhibitory inputs to the LC, as well as the possible damage that noradrenergic neurons suffer after the induction of neuropathic pain through chronic constriction injury (CCI). Neuropathic pain was induced in male Sprague-Dawley rats, and the expression of the vesicular glutamate transporter 1 or 2 (VGLUT1 or VGLUT2), vesicular GABA transporter (VGAT), and cleaved caspase-3 (CC3) was analyzed by immunofluorescence 7 (CCI7d) or 28 days after the original lesion (CCI28d). While no significant differences in the density of VGLUT1 puncta were evident, CCI7d induced a significant increase in the perisomatic VGLUT2/VGAT ratio relative to Sham-operated and CCI28d animals. By contrast, when the entire region of LC is evaluated, there was a significant reduction in the density of VGLUT2 puncta in CCI28d animals, without changes in VGLUT2/VGAT ratio relative to the CCI7d animals. Additionally, changes in the noradrenergic soma size, and a lower density of mitochondria and lysosomes were evident in CCI28d animals. Interestingly, enhanced expression of the apoptotic marker CC3 was also evident in the CCI28d rats, mainly co-localizing with glial fibrillary acidic protein but not with any neuronal or noradrenergic marker. Overall, short-term pain appears to lead to an increase of markers of excitatory synapses in the perisomatic region of noradrenergic cells in the LC, an effect that is lost after long-term pain, which appears to activate apoptosis.

Apoptotic Features in Non-Apoptotic Processes

Apoptosis is the most thoroughly studied type of regulated cell death. Certain events, such as externalization of phosphatidylserine (PS) into the outer leaflet of plasma membrane, mitochondrial outer membrane permeabilization, caspase cascade activation, DNA fragmentation and blebbing, are widely considered to be hallmarks of apoptosis as well as being traditionally viewed as irreversible. This review shows that under particular circumstances these events can also participate in physiological processes not associated with initiation of apoptosis, such as cell differentiation, division, and motility, as well as non-apoptotic types of cell death. Moreover, these events may often be reversible. This review focuses on three processes: phosphatidylserine externalization, blebbing, and activation of apoptotic caspases. Mitochondrial outer membrane permeabilization and DNA fragmentation are not discussed.

Early-phase administration of human amnion-derived stem cells ameliorates neurobehavioral deficits of intracerebral hemorrhage by suppressing local inflammation and apoptosis

Background

Intracerebral hemorrhage (ICH) is a significant cause of death and disabilities. Recently, cell therapies using mesenchymal stem cells have been shown to improve ICH-induced neurobehavioral deficits. Based on these findings, we designed this study to evaluate the therapeutic efficacy and underlying mechanisms by which human amnion-derived stem cells (hAMSCs) would ameliorate neurobehavioral deficits of ICH-bearing hosts.

Methods

hAMSCs were induced from amnia obtained by cesarean section and administered intravenously to ICH-bearing mice during the acute phase. The mice were then subject to multitask neurobehavioral tests at the subacute phase. We attempted to optimize the dosage and timing of the hAMSC administrations. In parallel with the hAMSCs, a tenfold higher dose of human adipose-derived stem cells (ADSCs) were used as an experimental control. Specimens were obtained from the ICH lesions to conduct immunostaining, flow cytometry, and Western blotting to elucidate the underlying mechanisms of the hAMSC treatment.

Results

The intravenous administration of hAMSCs to the ICH-bearing mice effectively improved their neurobehavioral deficits, particularly when the treatment was initiated at Day 1 after the ICH induction. Of note, the hAMSCs promoted clinical efficacy equivalent to or better than that of hADSCs at 1/10 the cell number. The systemically administered hAMSCs were found in the ICH lesions along with the local accumulation of macrophages/microglia. In detail, the hAMSC treatment decreased the number of CD11b⁺CD45⁺ and Ly6G⁺ cells in the ICH lesions, while splenocytes were not affected. Moreover, the hAMSC treatment decreased the number of apoptotic cells in the ICH lesions. These results were associated with suppression of the protein expression levels of macrophage-related factors iNOS and TNFα.

Conclusions

Intravenous hAMSC administration during the acute phase would improve ICH-induced neurobehavioral disorders. The underlying mechanism was suggested to be the suppression of subacute inflammation and apoptosis by suppressing macrophage/microglia cell numbers and macrophage functions (such as TNFα and iNOS). From a clinical point of view, hAMSC-based treatment may be a novel strategy for the treatment of ICH.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-022-02411-3.

Neurogenesis Is Reduced at 48 h in the Subventricular Zone Independent of Cell Death in a Piglet Model of Perinatal Hypoxia-Ischemia

Cellular and tissue damage triggered after hypoxia-ischemia (HI) can be generalized and affect the neurogenic niches present in the central nervous system. As neuroregeneration may be critical for optimizing functional recovery in neonatal encephalopathy, the goal of the present work was to investigate the neurogenic response to HI in the neurogenic niche of the subventricular zone (SVZ) in the neonatal piglet. A total of 13 large white male piglets aged <24 h were randomized into two groups: i) HI group (n = 7), animals submitted to transient cerebral HI and resuscitation; and ii) Control group (n = 6), non-HI animals. At 48 h, piglets were euthanized, and the SVZ and its surrounding regions, such as caudate and periventricular white matter, were analyzed for histology using hematoxylin-eosin staining and immunohistochemistry by evaluating the presence of cleaved caspase 3 and TUNEL positive cells, together with the cell proliferation/neurogenesis markers Ki67 (cell proliferation), GFAP (neural stem cells processes), Sox2 (neural stem/progenitor cells), and doublecortin (DCX, a marker of immature migrating neuroblasts). Hypoxic-ischemic piglets showed a decrease in cellularity in the SVZ independent of cell death, together with decreased length of neural stem cells processes, neuroblast chains area, DCX immunoreactivity, and lower number of Ki67 + and Ki67 + Sox2 + cells. These data suggest a reduction in both cell proliferation and neurogenesis in the SVZ of the neonatal piglet, which could in turn compromise the replacement of the lost neurons and the achievement of global repair.

Microglia and Macrophages in Neuroprotection, Neurogenesis, and Emerging Therapies for Stroke

Stroke remains the number one cause of morbidity in the United States. Within weeks to months after an ischemic event, there is a resolution of inflammation and evidence of neurogenesis; however, years following a stroke, there is evidence of chronic inflammation in the central nervous system, possibly by the persistence of an autoimmune response to brain antigens as a result of ischemia. The mechanisms underlying the involvement of macrophage and microglial activation after stroke are widely acknowledged as having a role in ischemic stroke pathology; thus, modulating inflammation and neurological recovery is a hopeful strategy for treating the long-term outcomes after ischemic injury. Current treatments fail to provide neuroprotective or neurorestorative benefits after stroke; therefore, to ameliorate brain injury-induced deficits, therapies must alter both the initial response to injury and the subsequent inflammatory process. This review will address differences in macrophage and microglia nomenclature and summarize recent work in elucidating the mechanisms of macrophage and microglial participation in antigen presentation, neuroprotection, angiogenesis, neurogenesis, synaptic remodeling, and immune modulating strategies for treating the long-term outcomes after ischemic injury.

Histone Methyltransferase Dot1L Contributes to RIPK1 Kinase-Dependent Apoptosis in Cerebral Ischemia/Reperfusion

Background

Neuron apoptosis is a pivotal process for brain damage in cerebral ischemia. Dot1L (disruptor of telomeric silencing 1‐like) is only known histone H3K79 methyltransferase. It is not clear whether the role and mechanism of Dot1L on cerebral ischemia is related to regulate neuron apoptosis.

Methods and Results

We use a combination of mice middle cerebral artery occlusion stroke and neurons exposed to oxygen‐glucose deprivation followed by reoxygenation to investigate the role and mechanism of Dot1L on cerebral ischemia. We find knockdown or inhibition of Dot1L reversed ischemia‐induced neuronal apoptosis and attenuated the neurons injury treated by oxygen‐glucose deprivation followed by reoxygenation. Further, blockade of Dot1L prevents RIPK1 (receptor‐interacting protein kinase 1)‐dependent apoptosis through increased RIPK1 K63‐ubiquitylation and decreased formation of RIPK1/Caspase 8 complexes. In line with this, H3K79me3 enrichment in the promoter region of deubiquitin‐modifying enzyme A20 and deubiquitinase cylindromatosis gene promotes the increasing expression in oxygen‐glucose deprivation followed by reoxygenation ‐induced neuronal cells, on the contrary, oxygen‐glucose deprivation followed by reoxygenation decreases H3K79me3 level in the promoter region of ubiquitin‐modifying enzyme cIAP1 (cellular inhibitors of apoptosis proteins), and both these factors ultimately cause K63‐deubiquitination of RIPK1. Importantly, knockdown or inhibition of Dot1L in vivo attenuates apoptosis in middle cerebral artery occlusion mice and reduces the extent of middle cerebral artery occlusion ‐induced brain injury.

Conclusions

These data support for the first time, to our knowledge, that Dot1L regulating RIPK1 to the apoptotic death trigger contributes to cerebral ischemia injury. Therefore, targeting Dot1L serves as a new therapeutic strategy for ischemia stroke.

Therapeutic Effects of Hydroalcoholic Extracts from the Ancient Apple Mela Rosa dei Monti Sibillini in Transient Global Ischemia in Rats

The Mela Rosa dei Monti Sibillini is an ancient apple variety cultivated by Romans in the foothills of the Sibillini Mountains, central Italy, showing potential as a source of nutraceuticals. The purpose of this study was to evaluate the protective effects of the hydroalcoholic extracts from the peel (APE) and pulp (APP) of this fruit in an animal model of transient global ischemia. Chemical constituents were analyzed by liquid chromatography–mass spectrometry (LC-DAD-MSⁿ) indicating several polyphenols such as B-type procyanidins, quercetin derivatives and hydroxycinnamic acids as the main bioactive components. Acute pre-treatment of extracts (30 mg/kg, i.p.) significantly decreased the brain levels of the pro-inflammatory cytokines IL-1β (p < 0.01) and TNF-α (p < 0.001 and p < 0.01 for APE and APP, respectively), the expression of caspase-3 (p < 0.01, For APE) and MDA (p < 0.05), a lipid peroxidation biomarker in rats. Both extracts restricted the pathological changes of the brain induced by ischemic stroke in hematoxylin and eosin assay. Moreover, they improved the scores of behavioral tests in grid-walking and modified neurological severity scores (mNSS) tests. In conclusion, these results proved this ancient Italian apple is a source of nutraceuticals able to protect/prevent damage from brain ischemia.

ATG5 is instrumental in the transition from autophagy to apoptosis during the degeneration of tick salivary glands

Female tick salivary glands undergo rapid degeneration several days post engorgement. This degeneration may be caused by the increased concentration of ecdysone in the hemolymph during the fast feeding period and both autophagy and apoptosis occur. In this work, we first proved autophagy-related gene (ATG) and caspase gene expression peaks during degeneration of the tick salivary glands. We explored the regulatory role of Rhipicephalus haemaphysaloides autophagy-related 5 (RhATG5) in the degeneration of tick salivary glands. During the fast feeding phase, RhATG5 was cleaved and both calcium concentration and the transcription of Rhcalpains increased in the salivary glands. Recombinant RhATG5 was cleaved by μ-calpain only in the presence of calcium; the mutant RhATG5^191-199Δ was not cleaved. Treatment with 20-hydroxyecdysone (20E) led to programmed cell death in the salivary glands of unfed ticks in vitro, RhATG8-phosphatidylethanolamine (PE) was upregulated in ticks treated with low concentration of 20E. Conversely, RhATG8-PE decreased and Rhcaspase-7 increased in ticks treated with a high concentration of 20E and transformed autophagy to apoptosis. High concentrations of 20E led to the cleavage of RhATG5. Calcium concentration and expression of Rhcalpains were also upregulated in the tick salivary glands. RNA interference (RNAi) of RhATG5 in vitro inhibited both autophagy and apoptosis of the tick salivary glands. RNAi of RhATG5 in vivo significantly inhibited the normal feeding process. These results demonstrated that high concentrations of 20E led to the cleavage of RhATG5 by increasing the concentration of calcium and stimulated the transition from autophagy to apoptosis.

Ticks are well-known pathogen vectors which transmitted virus, bacterial and protozoan. They are considered to be second only to mosquitoes as global vectors of human diseases. Most tick-borne pathogens (TBPs) are transmitted to hosts through tick bites assisted by saliva. Control of ticks has been achieved primarily by the application of acaricides, a method that has drawbacks such as environmental contamination and selection of pesticide-resistant ticks. Understanding the tick physiological characteristics is the key step for this objective; however, there are knowledge gap remained in tick physiology. Tick salivary glands rapidly degenerate and disappear within 4 days post engorgement. In this research, we are focused on tick salivary glands rapidly degeneration within 4 days post engorgement, and made several highlights findings: The first work demonstrated that 20E promotes both autophagy and apoptosis during tick salivary gland degeneration; RhATG5 is the first reported ATG5 homologue in ticks; RhATG5 play an important role in both autophagy and apoptosis during the degeneration of tick salivary glands.

Evaluation of Caspase-3 Activity During Apoptosis with Fluorescence Lifetime-Based Cytometry Measurements and Phasor Analyses

Caspase-3 is a well-described protease with many roles that impact the fate of a cell. During apoptosis, caspase-3 acts as an executioner caspase with important proteolytic functions that lead to the final stages of programmed cell death. Owing to this key role, caspase-3 is exploited intracellularly as a target of control of apoptosis for therapeutic outcomes. Yet the activation of caspase-3 during apoptosis is challenged by other roles and functions (e.g., paracrine signaling). This brief report presents a way to track caspase-3 levels using a flow cytometer that measures excited state fluorescence lifetimes and a signal processing approach that leads to a graphical phasor-based interpretation. An established Förster resonance energy transfer (FRET) bioprobe was used for this test; the connected donor and acceptor fluorophore is cleavable by caspase-3 during apoptosis induction. With the cell-by-cell decay kinetic data and phasor analyses we generate a caspase activation trajectory, which is used to interpret activation throughout apoptosis. When lifetime-based cytometry is combined with a FRET bioprobe and phasor analyses, enzyme activation can be simplified and quantified with phase and modulation data. We envision extrapolating this approach to high content screening, and reinforce the power of phasor approaches with cytometric data. Analyses such as these can be used to cluster cells by their phase and modulation "lifetime fingerprint" when the intracellular fluorescent probe is utilized as a sensor of enzyme activity. © 2020 The Authors. Cytometry Part A published by Wiley Periodicals LLC on behalf of International Society for Advancement of Cytometry.

XQ-1H attenuates ischemic injury in PC12 cells via Wnt/β-catenin signaling though inhibition of apoptosis and promotion of proliferation

10-O-(N,N-dimethylaminoethyl)-ginkgolide B methanesulfonate (XQ-1H) is a new derivative of ginkgolide B and has previously been proven to exert neuroprotective effects on ischemic injury. However, it is not clear whether XQ-1H affects the cell survival and proliferation in oxygen-glucose deprivation/reoxygenation (OGD/R) damaged PC12 cells. Our results showed that OGD/R improved cell viability after 24 hr of posttreatment with XQ-1H (10 or 5 μM), inhibiting cell injury and apoptosis by upregulating the expression of brain-derived neurotrophic factor, nerve growth factor, and antiapoptotic B-cell lymphoma-extra large, while reducing proapoptotic cleaved caspase-3 protein. By introducing the Wnt/β-catenin signaling inhibitor XAV-939 and 5-bromo-2'-deoxyuridine staining, it was proved that XQ-1H promoted the proliferation of PC12 cells in a Wnt-signal-dependent manner via inhibiting the activation of glycogen synthase kinase-3β after phosphatidylinositol 3-kinase/protein kinase B signal activation, thereby activating Wnt1, β-catenin, and the expression of downstream neurogenic differentiation 1 and cyclin D1, which was comparable to Wnt/β-catenin signaling agonist 4,6-disubstituted pyrrolopyrimidine. We conclude that XQ-1H, after OGD/R damage to PC12 cells, may limit cell apoptosis in a Wnt/β-catenin signal-dependent manner, promoting cell proliferation and survival.

Brain-specific NRSF deficiency aggravates dopaminergic neurodegeneration and impairs neurogenesis in the MPTP mouse model of Parkinson's disease

Degeneration of the dopaminergic neurons in the substantia nigra and the resultant dopamine depletion from the striatum are the hallmarks of Parkinson's disease (PD) and are responsible for the disease's cardinal motor symptoms. The transcriptional repressor Neuron-Restrictive Silencer Factor (NRSF), also known as RE1-Silencing Transcription Factor (REST), was originally identified as a negative regulator of neuron-specific genes in non-neuronal cells. Our previous study showed that mice deficient in neuronal NRSF/REST expression were more vulnerable to the noxious effects of the dopaminergic neurotoxin MPTP. Here, we found that brain-specific deletion of NRSF/REST led to more severe damages to the nigrostriatal pathway and long-lasting behavioral impairments in mice challenged with MPTP. Moreover, compared to wild-type controls, these mice showed increased neurogenesis shortly after MPTP exposure, but reduced neurogenesis later on. These results suggest that NRSF/REST acts as a negative modulator of neurogenesis and a pro-survival factor of neural stem cells under both normal conditions and during the course of PD.

Initiator and executioner caspases in salivary gland apoptosis of Rhipicephalus haemaphysaloides

BACKGROUND

Apoptosis is fundamental in maintaining cell balance in multicellular organisms, and caspases play a crucial role in apoptosis pathways. It is reported that apoptosis plays an important role in tick salivary gland degeneration. Several different caspases have been found in ticks, but the interactions between them are currently unknown. Here, we report three new caspases, isolated from the salivary glands of the tick Rhipicephalus haemaphysaloides.

METHODS

The full-length cDNA of the RhCaspases 7, 8 and 9 genes were obtained by transcriptome, and RhCaspases 7, 8 and 9 were expressed in E. coli; after protein purification and immunization in mice, specific polyclonal antibodies (PcAb) were created in response to the recombinant protein. Reverse-transcription quantitative PCR (RT-qPCR) and western blot were used to detect the existence of RhCaspases 7, 8 and 9 in ticks. TUNEL assays were used to determine the apoptosis level in salivary glands at different feeding times after gene silencing. The interaction between RhCaspases 7, 8 and 9 were identified by co-transfection assays.

RESULTS

The transcription of apoptosis-related genes in R. haemaphysaloides salivary glands increased significantly after tick engorgement. Three caspase-like molecules containing conserved caspase domains were identified and named RhCaspases 7, 8 and 9. RhCaspase8 and RhCaspase9 contain a long pro-domain at their N-terminals. An RT-qPCR assay demonstrated that the transcription of these three caspase genes increased significantly during the engorged periods of the tick developmental stages (engorged larval, nymph, and adult female ticks). Transcriptional levels of RhCaspases 7, 8 and 9 in salivary glands increased more significantly than other tissues post-engorgement. RhCaspase9-RNAi treatment significantly inhibited tick feeding. In contrast, knockdown of RhCaspase7 and RhCaspase8 had no influence on tick feeding. Compared to the control group, apoptosis levels were significantly reduced after interfering with RhCaspase 7, 8 and 9 expressions. Co-transfection assays showed RhCaspase7 was cleaved by RhCaspases 8 and 9, demonstrating that RhCaspases 8 and 9 are initiator caspases and RhCaspase7 is an executioner caspase.

CONCLUSIONS

To the best of our knowledge, this is the first study to identify initiator and executioner caspases in ticks, confirm the interaction among them, and associate caspase activation with tick salivary gland degeneration.

Implication of JAK1/STAT3/SOCS3 Pathway in Aging of Cerebellum of Male Rat: Histological and Molecular study

Aging causes morphological and functional changes in the cerebellum. This work aimed to demonstrate the implication of JAK1/STAT3/SOCS3 on aging-induced changes of rat cerebellum. Thirty male rats were divided into: adult (12 months), early senile (24 months) and late senile (32 months) groups. Immunohistochemical reaction of the cerebellum to GFAP and caspase-3 was assessed and the expression of JAK1, STAT3, SOCS3 proteins was also evaluated. TNFα as well as the activities of malondialdehyde (MDA) and reduced glutathione (GSH) in cerebellar tissue were also measured. The cerebellum of late senile rats revealed more degenerative changes than early senile rats in the form of increase in GFAP and caspase-3 immunoreaction. Additionally, there was decrease in JAK1and STAT3 expression in early and late senile rats and increase in SOCS3 when compare early and late senile groups with adult one. Enhancement of TNFα was noticed with aging as well as significant decrease in GSH and increase in MDA in early senile group. Moreover, late senile group revealed significant decrease in GSH and increase in MDA. It could be concluded that aging resulting in variable changes of the cerebellum as detected by morphological changes, immunohistochemical reactions of caspase-3 and GFAP and expression of JAK1/STAT3/SOCS3 proteins. Additionally, inflammatory marker TNFα and the activity of oxidative/antioxidative stress markers; malondialdehyde (MDA) and reduced glutathione (GSH) were also affected with aging.

Neutrophil extracellular traps released by neutrophils impair revascularization and vascular remodeling after stroke

Neovascularization and vascular remodeling are functionally important for brain repair after stroke. We show that neutrophils accumulate in the peri-infarct cortex during all stages of ischemic stroke. Neutrophils producing intravascular and intraparenchymal neutrophil extracellular traps (NETs) peak at 3-5 days. Neutrophil depletion reduces blood-brain barrier (BBB) breakdown and enhances neovascularization at 14 days. Peptidylarginine deiminase 4 (PAD4), an enzyme essential for NET formation, is upregulated in peri-ischemic brains. Overexpression of PAD4 induces an increase in NET formation that is accompanied by reduced neovascularization and increased BBB damage. Disruption of NETs by DNase 1 and inhibition of NET formation by genetic ablation or pharmacologic inhibition of PAD increases neovascularization and vascular repair and improves functional recovery. Furthermore, PAD inhibition reduces stroke-induced STING-mediated production of IFN-β, and STING knockdown and IFN receptor-neutralizing antibody treatment reduces BBB breakdown and increases vascular plasticity. Collectively, our results indicate that NET release impairs vascular remodeling during stroke recovery.

XQ-1H alleviates cerebral ischemia in mice through inhibition of apoptosis and promotion of neurogenesis in a Wnt/β-catenin signaling dependent way

AIMS

10-O-(N,N-dimethylaminoethyl)-ginkgolide B methanesulfonate (XQ-1H), a new derivative of ginkgolide B, has drawn great attention for its potent bioactivities against ischemia-induced injury. The purpose of this study was to further investigate the effect of XQ-1H against acute ischemic stroke by inducing middle cerebral artery occlusion/reperfusion (MCAO/R) injuries in mice.

MAIN METHODS

Treatment of XQ-1H (78 or 39 mg/kg, i.g., bid) 2 h after MCAO improved motor skills and ameliorated the severity of brain infarction and apoptosis seen in the mice by diminishing pathological changes and the activation of a pro-apoptotic protein Cleaved-Caspase-3, which in turn induced anti-apoptotic Bcl-xL. Through introducing Wnt/β-catenin signaling inhibitor XAV-939, XQ-1H was proven to intensively promoted neurogenesis in the peri-infarct cortex, subventricular area (SVZ) and the dentate gyrus (DG) subgranular area (SGZ) in a Wnt signal dependent way by compromising the activation of GSK3β, which in turn upregulated Wnt1, β-catenin, Neuro D1 and Cyclin D1, most possibly through the activation of PI3K/Akt signaling via the upregulation of brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF).

KEY FINDINGS

We conclude that XQ-1H preserved the motor functions, limited apoptosis, and concomitantly promoted neurogenesis-related protein expression by Wnt signaling-dependently compromising GSK3β/Caspase-3 activity and enhancing the expression of Wnt1/β-catenin/Neuro D1/Cyclin D1 and Bcl-xL.

SIGNIFICANCE

This research may benefit the development of stroke therapeutics targeting neurogenesis through Wnt upregulation by XQ-1H.

Tetrahydroxystilbene Glucoside Suppresses NAPDH Oxidative Stress to Mitigate Apoptosis and Autophagy Induced by Cerebral Ischemia/Reperfusion Injury in Mice

Tetrahydroxystilbene glucoside (TSG) is the active ingredient extracted from the traditional Chinese medicine Fallopia multiflora, which has extensive pharmacological activities. The current study aimed to observe the neuroprotective mechanism of TSG in the ischemia/reperfusion (I/R) brain injury-induced apoptosis and autophagy from the point of view of oxidative stress (OS). The middle cerebral artery occlusion (MCAO) model was prepared through the suture-occluded method, and TSG was administered through tail vein injection at the time of reperfusion at the doses of 3.0, 6.0, and 12.0 mg/kg. Compared with sham group, the neurological score in I/R mice was increased (P<0.05), along with remarkably elevated cerebral infarct volume (P<0.05); while TSG administration could reduce the neurological score and cerebral infarct volume (P<0.05) and improve the neuronal damage in ischemic cortex and hippocampus (P<0.05). The expression of NOX4, activated caspase-3(9), and Beclin 1 (P<0.05), as well as the LC3BII/I ratio, had been markedly elevated (P<0.05), while TSG administration could effectively suppress the expression of the above-mentioned proteins (P<0.05). In conclusion, TSG shows obvious protection against brain injury in I/R mice, and its mechanism may be related to suppressing the NADPH-induced OS and reducing neuronal apoptosis as well as autophagy.

Administration of troxerutin and cerebroprotein hydrolysate injection alleviates cerebral ischemia/reperfusion injury by down-regulating caspase molecules

BACKGROUND

Cerebral ischemia/reperfusion injury (I/R injury) is an important pathological process for nervous system. The I/R injury usually causes cerebral hypoxia, infarct or stroke. This study aimed to evaluate effects of troxerutin and cerebroprotein hydrolysate injection (TC) on I/R injury in rat models.

METHODS

Middle-cerebral artery occlusion/reperfusion (MCAO/R) rat models were established. Rats were divided into normal control (NC), MCAO/R rat model (injecting saline) and MCAO/R rats administrating with TC group (injecting with TC at concentration of 2 mL/100 g body weight). Neurological scores were evaluated with Garcia scale. Magnetic resonance imaging (MRI) was employed to observe infarct area, contralateral area and apparent diffusion coefficient (ADC) values. Cerebral infarct size was examined and visualized by staining with 2,3,5-triphenyltetrazolium chloride (TTC). Western blotting assay was used to determine caspase-1, caspase-3 and caspase-8 expression.

RESULTS

The infarct size of mice in MCAO/R+TC group was smaller significantly compared to that in MCAO/R group (p<0.05). The infarct/contralateral area ratio of T2 and T2 Flair signals in MCAO/R+TC group were lower significantly compared to that in MCAO/R group (p<0.05). ADC values in MCAO/R+TC group were significantly enhanced compared to that in MCAO/R group (p<0.05). The troxerutin and cerebroprotein treatment significantly increased neurological scores compared to that in MCAO/R group (p<0.05). Troxerutin and cerebroprotein treatment significantly decreased expression of caspase-1, caspase-3, caspase-8 compared to that in MCAO/R group (p<0.05).

CONCLUSION

Troxerutin and cerebroprotein administration alleviated cerebral I/R injury by down-regulating caspase molecules.

The Antiapoptosis Effect of Geum japonicum Thunb. var. chinense Extracts on Cerebral Ischemia Reperfusion Injury via PI3K/Akt Pathway

Geum japonicum Thunb. var. chinense (GJ) is a type of wild vegetable found in China and other Asian countries; it has been reported that its extracts possess a neuroprotective effect against cerebral ischemia reperfusion (CIR) injury. The aim of this study is to explore the effect GJ extracts on transient focal CIR injury and neurons apoptosis and to clarify its possible underlying mechanisms in vivo. Our results indicated that pretreatment with GJ extracts significantly ameliorated the infarct volume, decreased neurological deficits, lessened neural cells apoptosis, downregulated GFAP activity level, and increased surviving neurons. Moreover, GJ extracts preadministration increased Bcl-2 levels and attenuated the increase in the expressions of Bax and it also lowered the cleaved caspase-3 activity in ischemic cortex tissues which was caused by CIR and increased the expression of PI3K and p-Akt. The above effects of high dose of GJ (GJ-H) group were much better than those of low dose of GJ (GJ-L), which indicated that GJ extracts may be helpful in the suppression of CIR injury with a dose-dependent manner.

Periostin alters transcriptional profile in a rat model of isoproterenol-induced cardiotoxicity

Periostin is an extracellular matrix protein from the fasciclin family that guides cellular trafficking and extracellular matrix organization. Periostin stimulates mature cardiomyocytes to reenter the cell cycle. The molecular mechanism behind such stimulation remains to be explored. A DNA microarray technology constituting 30,429 gene-level probe sets was utilized to investigate effects of recombinant murine periostin peptide on the gene expression pattern in a rat model of isoproterenol (ISO)-induced myocardial injury. The experiment was performed on 84 adult male Sprague-Dawley rats in four groups ( n = 21): (1) control group, (2) only periostin applied group, (3) ISO cardiotoxicity group, and (4) ISO + periostin group. The experiment was continued for 28 days, and rats were killed on days 1, 7, and 28 ( n = 7). Microarray analyses revealed that periostin significantly altered the expression of at least ±2-fold of 2474 genes in the ISO + periostin group compared to the ISO cardiotoxicity group of which 521 genes altered out of 30,429 gene-level probe sets. Ingenuity pathway analysis indicated that multiple pathway networks were affected by periostin, with predominant changes occurring in the expression of genes involved in oxidative phosphorylation, oxidative stress, fatty acid metabolism, and TNF-α NF-κB signaling pathways. These findings indicate that periostin alters gene expression profile in the ISO-induced myocardial injury and modulates local myocardial inflammation, possibly mitigating inflammation through TNF-α NF-κB signaling pathway along with a decreased Casp7 activity and apoptotic cell death.

Astrocytes and radial glia-like cells, but not neurons, display a nonapoptotic increase in caspase-3 expression following exercise

BACKGROUND

Exercise induces plasticity in the hippocampus, which includes increases in neurogenesis, the proliferation of new neurons, and angiogenesis, the sprouting of new capillaries from preexisting blood vessels. Following exercise, astrocytes also undergo morphological changes that parallel the events occurring in the neurovascular system. Interestingly, there have also been reports of apoptosis in the hippocampus following aerobic exercise. This experiment aimed to identify which population of hippocampal cells undergoes apoptosis after an acute bout of exercise.

METHODS

Cleaved caspase-3, a terminal protein in the apoptotic cascade, was initially used to identify apoptotic cells in the hippocampus after rats completed an acute bout of exercise. Next, the proportion of immature neurons, adult neurons, astrocytes, or radial glia-like cells expressing cleaved caspase-3 was quantified. TUNEL staining was completed as a second measure of apoptosis.

RESULTS

Following exercise, cleaved caspase-3 expression was increased in the CA1 and DG regions of the hippocampus. Cleaved caspase-3 was not highly expressed in neuronal populations, and expression was not increased in these cells postexercise. Instead, cleaved caspase-3 was predominantly expressed in astrocytes. Following exercise, there was an increased number of cleaved caspase-3 positive astrocytes in DG and CA1, and cleaved caspase-3 positive radial glia-like cells located in the subgranular zone. To determine whether cleaved caspase-3 expression in these glial cells was associated with apoptosis, a TUNEL assay was completed. TUNEL staining was negligible in all groups and did not mirror the pattern of caspase-3 labeling.

CONCLUSIONS

Cleaved caspase-3 expression was detected largely in non-neuronal cell populations, and the pattern of cleaved caspase-3 expression did not match that of TUNEL. This suggests that after exercise, cleaved caspase-3 expression may serve a nonapoptotic role in these hippocampal astrocytes and radial glia-like cells. It will be important to identify the function of exercise-induced cleaved caspase-3 expression in the future experiments.

Growth Differentiation Factor 11 Promotes Neurovascular Recovery After Stroke in Mice

Background: Growth differentiation factor 11 (GDF11), a member of transforming growth factor-β (TGF-β) superfamily, was shown to rejuvenate cardiac and skeletal muscle function and to improve cerebral vasculature and neurogenesis in old mice. However, recent experimental data reported that raising GDF11 levels inhibited skeletal muscle regeneration and had no effect on cardiac hypertrophy. Our aim was to investigate the effects of GDF11 on brain repair during the recovery phase after stroke.

Methods: Mice were subjected to distal middle cerebral artery occlusion, and recombinant GDF11 (rGDF11) was injected intraperitoneally once a day during days 7–13 after stroke. Neuronal precursor cells (NPCs) proliferation and angiogenesis were assayed at 14 days. Neuronal regeneration was assayed at 42 days. The beam-walking test and CatWalk were used to evaluate behavioral functions. Downstream pathways of GDF11 were also investigated.

Results: GDF11 was upregulated in the ipsilateral peri-infarct cortex and subventricular zone (SVZ) at 14 days after stroke. Treatment with rGDF11 enhanced the number of newborn NPCs and endothelial cells, microvascular length and area, and brain capillary perfusion. Western blots showed that rGDF11 upregulated brain-derived neurotrophic factor (BDNF) and increased the levels of proangiogenic factor angiopoietin-2 (Ang-2) and phosphorylation of vascular endothelial growth factor receptor-2 (VEGFR-2). We also found that rGDF11 upregulated the transcription factors Smad2 and Smad3 phosphorylation, but these activations were blocked by a TGF-β receptor inhibitor SB431542. Moreover, rGDF11-induced angiogenic remodeling and NPCs proliferation were reversed by injection of SB431542, suggesting that GDF11 may exert its effect via the TGF-β/Smad2/3 signaling pathway. Finally, treating mice with rGDF11 resulted in a significant increase in neuronal regeneration and functional recovery.

Conclusion: GDF11 promoted neurogenesis and angiogenesis and contributed to functional recovery after stroke in mice.

Electroacupuncture Inhibits Apoptosis of Peri-Ischemic Regions via Modulating p38, Extracellular Signal-Regulated Kinase (ERK1/2), and c-Jun N Terminal Kinases (JNK) in Cerebral Ischemia-Reperfusion-Injured Rats

BACKGROUND Previous studies suggested that inhibition of apoptosis prevents the dysfunction of ischemia-reperfusion injury. In the pathogenesis of ischemia-reperfusion injury, JNK/ERK1/2 and p38 play an essential role in regulation of cell apoptosis. Electroacupuncture (EA), a form of acupuncture, has demonstrated superiority in preventing ischemia-reperfusion injury, but the underlying mechanism is unclear. In the present study, we explored the effects of electroacupuncture at Shenting (GV24) and Baihui (GV20) acupoints on focal cerebral ischemia-reperfusion (MCAO) rats, and explored whether JNK/ERK1/2- and p38-mediated cell apoptosis are involved. MATERIAL AND METHODS The rats were divided into a sham operation control group, an ischemia group, and an electroacupuncture group with acupuncture applied for 10 days (30 min per day). TTC staining was used to calculate the ischemic brain volume. TUNEL staining and transmission electron microscopy were used to detect cell apoptosis. Western blot analysis and Bio-Plex were used to detect JNK, p38, ERK1/2, Bcl-2, and Bax protein expression. RESULTS We found that electroacupuncture at day 10 significantly reduced cerebral infarction. In addition, electroacupuncture suppressed activation of JNK and p38, while enhancing the activation of ERK1/2 in the peri-ischemic regions. Consequently, the effect of electroacupuncture on these pathways resulted in the inhibition of apoptosis, which was demonstrated by TUNEL and transmission electron microscopy. We found that electroacupuncture upregulated the anti-apoptotic Bcl-2/Bax ratio in peri-ischemic regions. CONCLUSIONS Our findings suggest that inhibition of cell apoptosis via regulating multiple signaling pathways might be a mechanism whereby electroacupuncture has a positive therapeutic effect on post-stroke impairment.

Learning on the Fly: The Interplay between Caspases and Cancer

The ease of genetic manipulation, as well as the evolutionary conservation of gene function, has placed Drosophila melanogaster as one of the leading model organisms used to understand the implication of many proteins with disease development, including caspases and their relation to cancer. The family of proteases referred to as caspases have been studied over the years as the major regulators of apoptosis: the most common cellular mechanism involved in eliminating unwanted or defective cells, such as cancerous cells. Indeed, the evasion of the apoptotic programme resulting from caspase downregulation is considered one of the hallmarks of cancer. Recent investigations have also shown an instrumental role for caspases in non-lethal biological processes, such as cell proliferation, cell differentiation, intercellular communication, and cell migration. Importantly, malfunction of these essential biological tasks can deeply impact the initiation and progression of cancer. Here, we provide an extensive review of the literature surrounding caspase biology and its interplay with many aspects of cancer, emphasising some of the key findings obtained from Drosophila studies. We also briefly describe the therapeutic potential of caspase modulation in relation to cancer, highlighting shortcomings and hopeful promises.

Direct pharmacological Akt activation rescues Alzheimer's disease like memory impairments and aberrant synaptic plasticity

Amyloid β (Aβ) is a key mediator for synaptic dysfunction and cognitive impairment implicated in Alzheimer's disease (AD). However, the precise mechanism of the toxic effect of Aβ is still not completely understood. Moreover, there is currently no treatment for AD. Protein kinase B (PKB, also termed Akt) is known to be aberrantly regulated in the AD brain. However, its potential function as a therapeutic target for AD-associated memory impairment has not been studied. Here, we examined the role of a direct Akt activator, SC79, in hippocampus-dependent memory impairments using Aβ-injected as well as 5XFAD AD model mice. Oligomeric Aβ injections into the 3rd ventricle caused concentration-dependent and time-dependent impairments in learning/memory and synaptic plasticity. Moreover, Aβ aberrantly regulated caspase-3, GSK-3β, and Akt signaling, which interact with each other in the hippocampus. Caspase-3 and GSK-3β inhibitor ameliorated memory impairments and synaptic deficits in Aβ-injected AD model mice. We also found that pharmacological activation of Akt rescued memory impairments and aberrant synaptic plasticity in both Aβ-treated and 5XFAD mice. These results suggest that Akt could be a therapeutic target for memory impairment observed in AD.

PD149163 induces hypothermia to protect against brain injury in acute cerebral ischemic rats

Therapeutic hypothermia is a promising strategy for acute cerebral ischemia via physical or pharmacological methods. In this study, we pharmacologically induced hypothermia on Sprague Dawley rats by intraperitoneally injecting PD149163. We found that mild hypothermia was induced by PD149163 treatment without local cerebral blood flow (LCBF) alteration. To evaluate the neuroprotective effects of PD149163, TTC staining, HE staining and Nissl's staining were performed in our study. We found that PD149163 could prevent neuronal damage, and inhibit proliferation and activation of glial cells induced by ischemia. Simultaneously, we observed PD149163 ameliorated apoptosis characterized by down-regulated caspase-3 and Bax, but elevated Bcl-2. Moreover, PD149163 dramatically reduced JNK and AMPK/mTOR signaling pathway activation, and thereby inhibited autophagy by increased P62 expression, decreased the ratio of LC₃-Ⅱ to LC₃-Ⅰ and the expression of Beclin. Taken together, the present findings reveal the therapeutic effects of PD149163-induced hypothermia in brain ischemia, and provide a new strategy for stroke treatment.

Exploring the model of PC12 apoptosis induced by OGSD/R through in vitro experiments

Aims

To explicit cell apoptosis trend in PC12 oxygen-glucose-serum deprivation/restoration (OGSD/R) model and provide experimental bases for neural cell simulation in ischemia reperfusion injury in vitro.

Methods

OGSD/R model was constructed using the passage PC12 cells in vitro. The profile of cell apoptosis was estimated by DAPI staining, Annexin V-FITC and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay, as well as the levels of apoptosis-related proteins, including procaspase-3 and caspase-12.

Results

PC12 apoptosis was induced by OGSD and aggravated after restoration. CCK8 assay indicated that cell activity reached minimum after 1h of oxygen-glucose-serum restoration (OGR). DAPI staining suggested that apoptosis was the most serious after 1h of OGR, causing apoptotic cell nucleus pyknosis, particle spot formation, and fracture of cells with serious apoptosis forming pieces, and nucleus disintegration. The percentage of apoptotic cells exhibited increased trend after restoration, and reached the highest at 1h of OGR. Moreover, the expression of procaspase-3 and caspase-12 were extremely enhanced after OGD, especially 1h after OGR.

Conclusions

PC12 apoptosis is induced by OGSD and aggravated after restoration. The apoptosis of PC12 reaches the highest at 1h after OGR, which may provide experimental bases for spinal cord ischemia reperfusion injury treatment.

Enriched housing promotes post-stroke functional recovery through astrocytic HMGB1-IL-6-mediated angiogenesis

Enriched environment (EE) is shown to promote angiogenesis, neurogenesis and functional recovery after ischemic stroke. However, the underlying mechanisms remain unclear. C57BL/6 mice underwent middle cerebral artery occlusion (60 min) followed by reperfusion, after which mice were housed in either standard environment (SE) or EE. Here we found that post-ischemic EE exhibited decreased depression and anxiety-like behavior, and promoted angiogenesis and functional recovery compared to SE mice. EE mice treated with high-mobility group box-1 (HMGB1) inhibitor glycyrrhizin had an increased post-stroke depression and anxiety-like behavior, and the angiogenesis and functional recovery were decreased. HMGB1 and interleukin-6 (IL-6) expression in astrocyte were increased in EE mice. EE mice treated with glycyrrhizin decreased, whereas EE mice treated with recombinant HMGB1 (rHMGB1) increased the levels of IL-6 and p-AKT. Blockade of IL-6 with anti-IL-6-neutralizing antibody in EE mice attenuated EE-mediated angiogenesis and functional recovery. Furthermore, our in vitro data revealed that in primary astrocyte cultures rHMGB1 promoted the expression of IL-6 in activated astrocytes. PI₃K/AKT signaling pathway was involved in HMGB1-mediated expression of astrocytic IL-6. Thus, our results reveal a previously uncharacterized property of HMGB1/IL-6 signaling pathway in EE-mediated angiogenesis and functional recovery after ischemic stroke.

氯化两面针碱对胃癌细胞株SGC7901凋亡的影响及初步机制

目的

探讨氯化两面针碱对胃癌细胞株SGC7901凋亡的影响, 并研究其可能的初步机制.

方法

MTT法检测不同浓度氯化两面针碱(0、5、10、20和40 μmol/L)对胃癌细胞株SGC7901存活率的影响; Hoechst染色观察SGC7901细胞的形态学; Annexin V-FITC/PI双染法检测SGC7901细胞的凋亡; JC-1单标法检测细胞内线粒体膜电位变化; 免疫印迹法检测caspase-3剪切体、caspase-9剪切体和PARP剪切体与其各自未激活体的蛋白表达变化.

结果

SGC7901的存活率随着氯化两面针碱浓度的增加而逐渐下降, 并与时间呈正相关; Hoechst染色与Annexin V-FITC/PI双染法结果分别显示氯化两面针碱干预后SGC7901细胞的凋亡特征更显著, 细胞凋亡率明显增多; 经过氯化两面针碱处理后, SGC7901细胞线粒体膜电位显著下降, caspase-3剪切体、caspase-9剪切体和PARP剪切体蛋白表达水平显著上升, 其未激活体蛋白表达明显下降.

结论

氯化两面针碱呈浓度依赖性抑制SGC7901细胞的存活率, 增加细胞凋亡率, 可能是通过激活内源性线粒体通路有关.

ADAMTS13 controls vascular remodeling by modifying VWF reactivity during stroke recovery

Angiogenic response is essential for ischemic brain repair. The von Willebrand factor (VWF)-cleaving protease disintegrin and metalloprotease with thrombospondin type I motif, member 13 (ADAMTS13) is required for endothelial tube formation in vitro, but there is currently no in vivo evidence supporting a function of ADAMTS13 in angiogenesis. Here we show that mice deficient in ADAMTS13 exhibited reduced neovascularization, brain capillary perfusion, pericyte and smooth muscle cell coverage on microvessels, expression of the tight junction and basement membrane proteins, and accelerated blood-brain barrier (BBB) breakdown and extravascular deposits of serum proteins in the peri-infarct cortex at 14 days after stroke. Deficiency of VWF or anti-VWF antibody treatment significantly increased microvessels, perfused capillary length, and reversed pericyte loss and BBB changes in Adamts13^-/- mice. Furthermore, we observed that ADAMTS13 deficiency decreased angiopoietin-2 and galectin-3 levels in the isolated brain microvessels, whereas VWF deficiency had the opposite effect. Correlating with this, overexpression of angiopoietin-2 by adenoviruses treatment or administration of recombinant galectin-3 normalized microvascular reductions, pericyte loss, and BBB breakdown in Adamts13^-/- mice. The vascular changes induced by angiopoietin-2 overexpression and recombinant galectin-3 treatment in Adamts13^-/- mice were abolished by the vascular endothelial growth factor receptor-2 antagonist SU1498. Importantly, treating wild-type mice with recombinant ADAMTS13 at 7 days after stroke markedly increased neovascularization and vascular repair and improved functional recovery at 14 days. Our results suggest that ADAMTS13 controls key steps of ischemic vascular remodeling and that recombinant ADAMTS13 is a putative therapeutic avenue for promoting stroke recovery.

von Willebrand factor contributes to poor outcome in a mouse model of intracerebral haemorrhage

Spontaneous intracerebral haemorrhage (ICH) is the most devastating stroke subtype and has no proven treatment. von Willebrand factor (VWF) has recently been demonstrated to promote inflammation processes. The present study investigated the pathophysiological role of VWF after experimental ICH. Functional outcomes, brain edema, blood-brain barrier (BBB) permeability, cerebral inflammation and levels of intercellular adhesion molecule-1 (ICAM-1) and matrix metalloproteinase-9 (MMP-9) were measured in a mouse model of ICH induced by autologous blood injection. We show that VWF were increased in the plasma and was accumulated in the perihematomal regions of mice subjected to ICH. Injection of VWF resulted in incerased expression of proinflammatory mediators and activation of ICAM-1 and MMP-9, associated with elevated myeloperoxidase, recruitment of neutrophils and microglia. Moreover, mice treated with VWF showed dramatically decreased pericyte coverage, more severe BBB damage and edema formation, and neuronal injury was increased compared with controls. In contrast, blocking antibodies against VWF reduced BBB damage and edema formation and improved neurological function. Together, these data identify a critical role for VWF in cerebral inflammation and BBB damage after ICH. The therapeutic interventions targeting VWF may be a novel strategy to reduce ICH-related injury.

Axonal Cleaved Caspase-3 Regulates Axon Targeting and Morphogenesis in the Developing Auditory Brainstem

Caspase-3 is a cysteine protease that is most commonly associated with cell death. Recent studies have shown additional roles in mediating cell differentiation, cell proliferation and development of cell morphology. We investigated the role of caspase-3 in the development of chick auditory brainstem nuclei during embryogenesis. Immunofluorescence from embryonic days E6–13 revealed that the temporal expression of cleaved caspase-3 follows the ascending anatomical pathway. The expression is first seen in the auditory portion of VIIIth nerve including central axonal regions projecting to nucleus magnocellularis (NM), then later in NM axons projecting to nucleus laminaris (NL), and subsequently in NL dendrites. To examine the function of cleaved caspase-3 in chick auditory brainstem development, we blocked caspase-3 cleavage in developing chick embryos with the caspase-3 inhibitor Z-DEVD-FMK from E6 to E9, then examined NM and NL morphology and NM axonal targeting on E10. NL lamination in treated embryos was disorganized and the neuropil around NL contained a significant number of glial cells normally excluded from this region. Additionally, NM axons projected into inappropriate portions of NL in Z-DEVD-FMK treated embyros. We found that the presence of misrouted axons was associated with more severe NL disorganization. The effects of axonal caspase-3 inhibition on both NL morphogenesis and NM axon targeting suggest that these developmental processes are coordinated, likely through communication between axons and their targets.

Neuroimmunological interactions in stroke

INTRODUCTION

Stroke is one of the leading causes of death in the world; its incidence is increasing due to increased life expectancy. However, treatment options for these patients are limited since no clinically effective drugs have been developed to date.

DEVELOPMENT

According to clinical evidence, a number of neurochemical changes take place after stroke, including energy depletion, increased free radical synthesis, calcium accumulation, neurotransmitter imbalance, excitotoxicity, and, at a later stage, immune system activation leading to inflammation. Immune response has been shown to be a major factor in disease progression. The release of proinflammatory cytokines such as TNF increase brain damage secondary to excitotoxicity and calcium accumulation, and promote free radical synthesis and cell death through various mechanisms. On the other hand, certain anti-inflammatory cytokines, such as IL-10 and IL-4, have been shown to have a neuroprotective effect and even promote neurogenesis and synapse remodeling, which makes immune modulation a promising treatment approach.

CONCLUSIONS

Understanding the relationship between the immune system and the nervous system not only deepens our knowledge of stroke but also provides new diagnostic, prognostic, and therapeutic strategies that may increase the quality of life of stroke patients.

Extremely low-frequency electromagnetic fields enhance the proliferation and differentiation of neural progenitor cells cultured from ischemic brains

In the mammalian brain, neurogenesis persists throughout the embryonic period and adulthood in the subventricular zone of the lateral ventricle and the granular zone (dentate gyrus) of the hippocampus. Newborn neural progenitor cells (NPCs) in the two regions play a critical role in structural and functional plasticity and neural regeneration after brain injury. Previous studies have reported that extremely low-frequency electromagnetic fields (ELF-EMF) could promote osteogenesis, angiogenesis, and cardiac stem cells' differentiation, which indicates that ELF-EMF might be an effective tool for regenerative therapy. The present studies were carried out to examine the effects of ELF-EMF on hippocampal NPCs cultured from embryonic and adult ischemic brains. We found that exposure to ELF-EMF (50 Hz, 0.4 mT) significantly enhanced the proliferation capability both in embryonic NPCs and in ischemic NPCs. Neuronal differentiation was also enhanced after 7 days of cumulative ELF-EMF exposure, whereas glial differentiation was not influenced markedly. The expression of phosphorylated Akt increased during the proliferation process when ischemic NPCs were exposed to ELF-EMF. However, blockage of the Akt pathway abolished the ELF-EMF-induced proliferation of ischemic NPCs. These data show that ELF-EMF promotes neurogenesis of ischemic NPCs and suggest that this effect may occur through the Akt pathway.Video abstract, Supplemental Digital Content 1, http://links.lww.com/WNR/A347.

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

Promoting regenerative repair, including neurogenesis and angiogenesis, may provide a new therapeutic strategy for treatment of stroke. P53, a well-documented transcription factor, has been reported to be involved in cerebral ischemia and also serves as an important regulator of vascular endothelial growth factor (VEGF). However, the role of p53 in endogenous regenerative repair after brain ischemia is poorly understood. In this study, we investigated the effects of PFT-α, a specific p53 inhibitor on neurogenesis and angiogenesis improvement and associated signal pathways in rats impaired by cerebral artery occlusion (MCAo). PFT-α induced neuroprotection, reduced infarct volume and neurological functional impairment after ischemic stroke. More importantly, neurogenesis and angiogenesis were greatly enhanced by PFT-α, and accompanied by increased expression of VEGF. Moreover, we got consistent results in neural stem cells (NSCs) isolated from fetal rats. In contrast, application of the anti-VEGF neutralizing antibody (RB-222) partially reversed PFT-α-induced neuroprotection and rescued p53 expression. Noteworthily, inhibition of p53 after ischemic stroke in these rats improved their outcomes via promotion of regenerative repair. In conclusion, PFT-α could serve as a promising therapeutic strategy for ischemic stroke by promoting regenerative repair.