Synergistic activation of caspase-3 by m-calpain after neonatal hypoxia-ischemia: a mechanism of "pathological apoptosis"?

Exploratory factor analysis yields grouping of brain injury biomarkers significantly associated with outcomes in neonatal and pediatric ECMO

In this two-center prospective cohort study of children on ECMO, we assessed a panel of plasma brain injury biomarkers using exploratory factor analysis (EFA) to evaluate their interplay and association with outcomes. Biomarker concentrations were measured daily for the first 3 days of ECMO support in 95 participants. Unfavorable composite outcome was defined as in-hospital mortality or discharge Pediatric Cerebral Performance Category > 2 with decline ≥ 1 point from baseline. EFA grouped 11 biomarkers into three factors. Factor 1 comprised markers of cellular brain injury (NSE, BDNF, GFAP, S100β, MCP1, VILIP-1, neurogranin); Factor 2 comprised markers related to vascular processes (vWF, PDGFRβ, NPTX1); and Factor 3 comprised the BDNF/MMP-9 cellular pathway. Multivariable logistic models demonstrated that higher Factor 1 and 2 scores were associated with higher odds of unfavorable outcome (adjusted OR 2.88 [1.61, 5.66] and 1.89 [1.12, 3.43], respectively). Conversely, higher Factor 3 scores were associated with lower odds of unfavorable outcome (adjusted OR 0.54 [0.31, 0.88]), which is biologically plausible given the role of BDNF in neuroplasticity. Application of EFA on plasma brain injury biomarkers in children on ECMO yielded grouping of biomarkers into three factors that were significantly associated with unfavorable outcome, suggesting future potential as prognostic instruments.

Contribution of mitochondria to postmortem muscle tenderization: a review

Postmortem meat tenderization is a process mediated by a series of biochemical reactions related to muscle cell death. Cell death is considered a sign that muscle has started to transform into meat. Mitochondria play a significant role in regulating and executing cell death, as they are an aggregation point for many cell death signals and are also the primary target organelle damaged by tissue anoxia. Mitochondrial damage is likely to have an expanded role in postmortem meat tenderization. This review presents current findings on mitochondrial damage induced by the accumulation of reactive oxygen species during postmortem anaerobic metabolism and on the impact of mitochondrial damage on proteolysis and discusses how this leads to improved tenderness during aging. The underlying mechanisms of mitochondrial regulation of postmortem muscle tenderization likely focus on the mitochondria's role in postmortem cell death and energy metabolism. The death process of postmortem skeletal muscle cells may exhibit multiple types, possibly involving transformation from autophagy to apoptosis and, ultimately, necroptosis or necrosis. Mitochondrial characteristics, especially membrane integrity and ATP-related compound levels, are closely related to the transformation of multiple types of dead postmortem muscle cells. Finally, a possible biochemical regulatory network in postmortem muscle tenderization is proposed.

The intersection between cysteine proteases, Ca2+ signalling and cancer cell apoptosis

Apoptosis is a highly complex and regulated cell death pathway that safeguards the physiological balance between life and death. Over the past decade, the role of Ca2+ signalling in apoptosis and the mechanisms involved have become clearer. The initiation and execution of apoptosis is coordinated by three distinct groups of cysteines proteases: the caspase, calpain and cathepsin families. Beyond its physiological importance, the ability to evade apoptosis is a prominent hallmark of cancer cells. In this review, we will explore the involvement of Ca2+ in the regulation of caspase, calpain and cathepsin activity, and how the actions of these cysteine proteases alter intracellular Ca2+ handling during apoptosis. We will also explore how apoptosis resistance can be achieved in cancer cells through deregulation of cysteine proteases and remodelling of the Ca2+ signalling toolkit.

The Effect of Acetyl-L-Carnitine (ALCAR) on Peripheral Nerve Regeneration in Animal Models: A Systematic Review

Peripheral neuropathies caused by the peripheral nervous system (PNS) damage can occur due to trauma and other disorders. They present as altered sensation, weakness, autonomic symptoms, and debilitating pain syndrome with a wide range of clinical signs. Acetyl-L-Carnitine (ALCAR) is a biological compound with essential roles in mitochondrial oxidative metabolism and anti-oxidant effects that protects mitochondria from oxidative damage and inhibits apoptosis caused by mitochondrial damage. This study is a systematic review and meta-analysis of the effects of ALCAR on peripheral nerve injuries. This review examines studies on treating traumatic peripheral neuropathies in which ALCAR is administered to rats with sciatic nerve injury with an appropriate control group. The articles were divided based on the mode of ALCAR administration. If one method was used in more than one article, their results were entered in the "Revman5.4" software and were meta-analyzed. Studies were selected from 1994 to 2018 on rats with varying physical injuries to their sciatic nerves. In one study, ALCAR was provided to rats in their drinking water, while in other studies, ALCAR was injected intra-peritoneally. Different mechanisms of ALCAR actions have been suggested in this study, but the underpinnings of the neuroprotective effects of ALCAR are still unclear. Further studies are mandatory to clarify the actual mechanisms of the neuroprotective activity of ALCAR. Based on the results of existing studies, ALCAR effectively increases the tolerance threshold of thermal and mechanical stimuli, reduces latency, and reduces apoptosis; finally, adjusting the dose and duration of administration may increase the dose and duration axon diameter.

Alpha1-antitrypsin protects the immature mouse brain following hypoxic-ischemic injury

Introduction: Preterm brain injury often leads to lifelong disabilities affecting both cognitive and motor functions, and effective therapies are limited. Alpha1-antitrypsin (AAT), an endogenous inhibitor of serine proteinases with anti-inflammatory, anti-apoptotic, and cytoprotective properties, might be beneficial in treating preterm brain injury. The aim of this study was to investigate whether AAT has neuroprotective effects in a mouse preterm brain injury model. Methods: Preterm brain injury was induced on postnatal day 5, and mouse pups' right common carotid arteries were cut between two ligations followed by hypoxia induction. Brain injury was evaluated through immunohistochemistry staining and magnetic resonance imaging. Fluoro-Jade B and immunohistochemistry staining were performed to investigate the neuronal cell death and blood-brain barrier (BBB) permeability. The motor function and anxiety-like behaviors were revealed by CatWalk gait analysis and the open field test. Results: After hypoxia-ischemia (HI) insult, brain injury was alleviated by AAT treatment, and this was accompanied by reduced BBB permeability, reduced neuronal cell death and caspase-3 activation, and inhibition of microglia activation. In addition, AAT administration significantly improved HI-induced motor function deficiencies in mice. The neuroprotective effect of AAT was more pronounced in male mice. Conclusion: AAT treatment is neuroprotective against preterm brain injury in neonatal mice, and the effect is more pronounced in males.

Anticancer mechanism studies of iridium(III) complexes inhibiting osteosarcoma HOS cells proliferation

Three iridium (III) polypyridine complexes [Ir(bzq)₂(maip)](PF₆) (Ir1，bzq = benzo[h]quinoline, maip = 3-aminophenyl-1H-imidazo[4,5-f][1,10]phenanthroline), [Ir(bzq)₂(apip)](PF₆) (Ir2, apip = 2-aminophenyl-1H-imidazo[4,5-f][1,10]phenanthroline) and [Ir(bzq)₂(paip)](PF₆) (Ir3, paip = 4-aminophenyl-1H-imidazo[4,5-f][1,10]phenanthroline) were synthesized and characterized. The cytotoxic activities of the three complexes against human osteosarcoma HOS, U2OS, MG63 and normal LO2 cells were evaluated by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) method. The results showed that Ir1-3 exhibited moderate antitumor activity against HOS with IC₅₀ of 21.8 ± 0. 4 μM,10.5 ± 1.8 μM and 7.4 ± 0.4 μM, respectively. We found that Ir1-3 can effectively inhibit HOS cells growth and blocked the cell cycle at the G0/G1 phase. Further studies revealed that complexes can increase intracellular reactive oxygen species (ROS) and Ca²⁺, which accompanied by mitochondria-mediated intrinsic apoptosis pathway. In addition, autophagy was also investigated. Taken together, the complexes induce HOS apoptosis through a ROS-mediated mitochondrial dysfunction pathway and inhibition of the PI3K (phosphatidylinositol 3-kinase)/AKT (protein kinase B)/mTOR (mammalian target of rapamycin) signaling pathway. This study provides useful help for understanding the anticancer mechanism of iridium (III) complexes toward osteosarcoma treatment.

Inhibition of Calpain Attenuates Degeneration of Substantia Nigra Neurons in the Rotenone Rat Model of Parkinson's Disease

In the central nervous system (CNS), calcium homeostasis is a critical determinant of neuronal survival. Calpain, a calcium-dependent neutral protease, is widely expressed in the brain, including substantia nigra (SN) dopaminergic (DA) neurons. Though calpain is implicated in human Parkinson's disease (PD) and corresponding animal models, the roles of specific ubiquitous calpain isoforms in PD, calpain-1 and calpain-2, remain poorly understood. In this study, we found that both isoforms are activated in a nigrostriatal pathway with increased phosphorylated synuclein following the administration of rotenone in Lewis rats, but calpain isoforms played different roles in neuronal survival. Although increased expression of calpain-1 and calpain-2 were detected in the SN of rotenone-administered rats, calpain-1 expression was not altered significantly after treatment with calpain inhibitor (calpeptin); this correlated with neuronal survival. By contrast, increased calpain-2 expression in the SN of rotenone rats correlated with neuronal death, and calpeptin treatment significantly attenuated calpain-2 and neuronal death. Calpain inhibition by calpeptin prevented glial (astroglia/microglia) activation in rotenone-treated rats in vivo, promoted M2-type microglia, and protected neurons. These data suggest that enhanced expression of calpain-1 and calpain-2 in PD models differentially affects glial activation and neuronal survival; thus, the attenuation of calpain-2 may be important in reducing SN neuronal loss in PD.

Resveratrol and Some of Its Derivatives as Promising Prophylactic Treatments for Neonatal Hypoxia-Ischemia

Due to the rate of occurrence of neonatal hypoxia-ischemia, its neuronal sequelae, and the lack of effective therapies, the development of new neuroprotective strategies is required. Polyphenols (including resveratrol) are molecules whose anti-apoptotic, anti-inflammatory, and anti-oxidative properties could be effective against the damage induced by neonatal hypoxia-ischemia. In this review article, very recent data concerning the neuroprotective role of polyphenols and the mechanisms at play are detailed, including a boost in brain energy metabolism. The results obtained with innovative approaches, such as maternal supplementation at nutritional doses, suggest that polyphenols could be a promising prophylactic treatment for neonatal hypoxia-ischemia.

Exploration on the Mechanism of Ubiquitin Proteasome System in Cerebral Stroke

Stroke’s secondary damage, such as inflammation, oxidative stress, and mitochondrial dysfunction, are thought to be crucial factors in the disease’s progression. Despite the fact that there are numerous treatments for secondary damage following stroke, such as antiplatelet therapy, anticoagulant therapy, surgery, and so on, the results are disappointing and the side effects are numerous. It is critical to develop novel and effective strategies for improving patient prognosis. The ubiquitin proteasome system (UPS) is the hub for the processing and metabolism of a wide range of functional regulatory proteins in cells. It is critical for the maintenance of cell homeostasis. With the advancement of UPS research in recent years, it has been discovered that UPS is engaged in a variety of physiological and pathological processes in the human body. UPS is expected to play a role in the onset and progression of stroke via multiple targets and pathways. This paper explores the method by which UPS participates in the linked pathogenic process following stroke, in order to give a theoretical foundation for further research into UPS and stroke treatment.

A new Hypoxic Ischemic Encephalopathy model in neonatal rats

BACKGROUND

Hypoxic-Ischemic Encephalopathy (HIE) occurs when an infant's brain does not receive adequate blood and oxygen supply, resulting in ischemic and hypoxic brain damage during delivery. Currently, supportive care and hypothermia have been the standard treatment for HIE. However, there are still a 20% mortality and most of the survivors are associated with significant neurodevelopmental disability. HIE animal model was first established by Vannucci et al., in 1981, and has been used extensively to explore the mechanisms of brain damage and its potential treatment. The Vannucci model involves the unilateral common carotid artery occlusion followed by 90 min hypoxia (8% oxygen). The purpose of this study is to define and validate a modified HIE model which mimics closely that of the human neonatal HIE.

METHOD

The classic Vannucci HIE model occludes one common carotid artery followed by 90 min hypoxia. In the new model, common carotid arteries were occluded bilaterally followed by breathing 8% oxygen in a hypoxic chamber for 90, 60 and 30 min, followed by the release of the common carotid artery ligatures, mimicking a reperfusion.

RESULT

We studied 110 neonatal rats in detail, following the modified in comparison with the classical Vannucci models. The classical Vannucci model has a consistent surgical mortality of 18% and the new modified models have a 20%-46%. While mortality depended on the duration of hypoxia, fifty-two animals survived for behavioral assessments and standard histology. The modified HIE model with 60 min of transient carotid occlusion is associated with a moderate brain damage, and has a 30% surgical mortality. This modified experimental model is regarded closer to the human situation than the classical Vannucci model.

Tunicamycin Induces Hepatic Stellate Cell Apoptosis Through Calpain-2/Ca2 +-Dependent Endoplasmic Reticulum Stress Pathway

It has been reported that calpain/caspase-mediated apoptosis induced by endoplasmic reticulum stress (ERS) in hepatic stellate cells (HSCs) by previous studies. At present, the activation of HSC is an important cause of liver fibrosis, and the induction of HSC apoptosis plays an irreplaceable role in reversing liver fibrosis. Therefore, it is of great significance to explore mechanisms of action that can induce HSC apoptosis for the reversal of hepatic fibrosis and the clinical prevention and treatment of hepatic-fibrosis-related diseases such as hepatitis, cirrhosis, and liver cancer. In the current study, we demonstrated that tunicamycin (a novel ERS inducer) can induce the apoptosis of HSCs and increase the concentration of intracellular Ca²⁺ and the expression of ERS protein GRP78, apoptosis protein caspase-12, and Bax, while it can decrease the antiapoptosis protein expression of Bcl-2. Our findings indicate that tunicamycin can induce HSCs apoptosis through calpain-2/Ca²⁺-dependent ERS pathway.

The Protective Role of the Long Pentraxin PTX3 in Spontaneously Hypertensive Rats with Heart Failure

Pentraxin 3 (PTX3) is synthesized locally and released into the circulation, reflecting local inflammation in the cardiovascular system. Therefore, we conducted a study to explore the effect of PTX3 in spontaneously hypertensive heart failure (SHHF) rats. Sprague Dawley (SD) and SHHF rats were treated with recombinant PTX3 protein, and the blood pressure (BP) and echocardiographic parameters were collected. Radioimmunoassay, enzyme immunoassay and enzyme-linked immunosorbent assay (ELISA) were applied to detect plasma levels of atrial/B-type natriuretic peptide (ANP/BNP) and PTX3. The pathological changes in the myocardial tissues were observed by hematoxylin and eosin (HE) and Masson stainings. The mRNA and protein expressions were detected by quantitative real-time reverse-transcription polymerase chain reaction (qPCR) and western blotting. Cardiomyocyte apoptosis was evaluated by TUNEL staining and DNA fragmentation test. Increased plasma concentrations of PTX3 were found in SHHF rats compared with SD rats, which was further enhanced by recombinant PTX3 protein. After injection with recombinant PTX3 protein, the heart function was improved in SHHF rats with the decreased systolic and diastolic BP, and the reduced plasma levels of ANP and BNP. Moreover, PTX3 improved the myocardial damage and interstitial fibrosis in SHHF rats with reduced cardiomyocyte apoptosis and decreased mRNA expressions of pro-inflammatory factors in myocardial tissues. PTX3 could decrease the BP and plasma levels of ANP and BNP in SHHF rats, as well as improve the inflammation, cardiomyocyte apoptosis, and pathological changes of myocardial tissues, suggesting it may be a useful intervention in the treatment of SHHF.

Neuronal let-7b-5p acts through the Hippo-YAP pathway in neonatal encephalopathy

Despite increasing knowledge on microRNAs, their role in the pathogenesis of neonatal encephalopathy remains to be elucidated. Herein, we identify let-7b-5p as a significant microRNA in neonates with moderate to severe encephalopathy from dried blood spots using next generation sequencing. Validation studies using Reverse Transcription and quantitative Polymerase Chain Reaction on 45 neonates showed that let-7b-5p expression was increased on day 1 in neonates with moderate to severe encephalopathy with unfavourable outcome when compared to those with mild encephalopathy. Mechanistic studies performed on glucose deprived cell cultures and the cerebral cortex of two animal models of perinatal brain injury, namely hypoxic-ischaemic and intrauterine inflammation models confirm that let-7b-5p is associated with the apoptotic Hippo pathway. Significant reduction in neuronal let-7b-5p expression corresponded with activated Hippo pathway, with increased neuronal/nuclear ratio of Yes Associated Protein (YAP) and increased neuronal cleaved caspase-3 expression in both animal models. Similar results were noted for let-7b-5p and YAP expression in glucose-deprived cell cultures. Reduced nuclear YAP with decreased intracellular let-7b-5p correlated with neuronal apoptosis in conditions of metabolic stress. This finding of the Hippo-YAP association with let-7b needs validation in larger cohorts to further our knowledge on let-7b-5p as a biomarker for neonatal encephalopathy.

Using next generation sequencing of dried blood spots and subsequent validation, Ponnusamy et al identify let-7b-5p as an elevated microRNA in neonates with moderate to severe encephalopathy. Using cell culture and murine models of perinatal brain injury they demonstrate that the effects of let-7b-5p are elicited via the Hippo-YAP pathway, which should be validated in large neonate cohorts to expand our understanding of let-7b-5p as a biomarker for neonatal encephalopathy.

VEGF121 Mediates Post-Hypoxia Cardioprotective Effects Via CaSR and Mitochondria-Dependent Protease Pathway

BACKGROUND

Cardiovascular disease is the major cause of death worldwide. Hypoxia-mediated apoptosis in cardiomyocytes is a major cause of cardiovascular disorders. Treatment with vascular endothelial growth factor (VEGF) protein has been tested but operational difficulties have limited its use. However, with the advancements of gene therapy, interest has risen in VEGF-based gene therapy in cardiovascular disorders. However, the precise mechanism by which VEGF replenishment rescues post-hypoxia damage in cardiomyocytes is not known.

OBJECTIVES

To investigate the effect of post-hypoxia VEGF121 expression using neonatal rat cardiomyocytes.

METHODS

Cardiomyocytes isolated from neonatal rats were used to establish an in vitro model of hypoxia-induced cardiac injury. The effect of VEGF overexpression, alone or in combination with small-molecule inhibitors targeting calcium channel, calcium sensitive receptors (CaSR), and calpain on cell growth and proliferation on hypoxia-induced cardiomyocyte injury were determined using an MTT assay, TUNEL staining, Annexin V/PI staining, lactate dehydrogenase and caspase activity. For statistical analysis, a value of P<0.05 was considered to be significant.

RESULTS

The effect of VEGF121 was found to be mediated by CaSR and calpain but was not dependent on calcium channels.

CONCLUSIONS

Our findings, even though using an in vitro setting, lay the foundation for future validation and pre-clinical testing of VEGF-based gene therapy in cardiovascular diseases.

Inhibition of extracellular regulated kinase (ERK)-1/2 signaling pathway in the prevention of ALS: Target inhibitors and influences on neurological dysfunctions

Cell signal transduction pathways are essential modulators of several physiological and pathological processes in the brain. During overactivation, these signaling processes may lead to disease progression. Abnormal protein kinase activation is associated with several biological dysfunctions that facilitate neurodegeneration under different biological conditions. As a result, these signaling pathways are essential in understanding brain disorders' development or progression. Recent research findings indicate the crucial role of extracellular signal-regulated kinase-1/2 (ERK-1/2) signaling during the neuronal development process. ERK-1/2 is a key component of its mitogen-activated protein kinase (MAPK) group, controlling certain neurological activities by regulating metabolic pathways, cell proliferation, differentiation, and apoptosis. ERK-1/2 also influences neuronal elastic properties, nerve growth, and neurological and cognitive processing during brain injuries. The primary goal of this review is to elucidate the activation of ERK1/2 signaling, which is involved in the development of several ALS-related neuropathological dysfunctions. ALS is a rare neurological disorder category that mainly affects the nerve cells responsible for regulating voluntary muscle activity. ALS is progressive, which means that the symptoms are getting worse over time, and there is no cure for ALS and no effective treatment to avoid or reverse. Genetic abnormalities, oligodendrocyte degradation, glial overactivation, and immune deregulation are associated with ALS progression. Furthermore, the current review also identifies ERK-1/2 signaling inhibitors that can promote neuroprotection and neurotrophic effects against the clinical-pathological presentation of ALS. As a result, in the future, the potential ERK-1/2 signaling inhibitors could be used in the treatment of ALS and related neurocomplications.

Mechanism of the growth and development of the posterior silk gland and silk secretion revealed by mutation of the fibroin light chain in silkworm

Silkworm, as a model organism, has very high economic value due to its silk secretion ability. Although a large number of studies have attempted to elucidate the mechanism of silk secretion, it remains unclear. In this study, the fibroin light chain (Fib-L) gene of silkworm was subjected to CRISPR/Cas9 editing, which yielded premature termination of translation at 135 aa. Compared with those of the wild type, the posterior silk glands (PSGs) of the homozygous mutants on the third day of the fifth instar showed obvious premature degeneration. Comparative transcriptome and proteomic analyses of the PSGs of wild-type individuals, heterozygous mutants and homozygous mutants were performed on the fourth day of the fifth instar. A GO enrichment analysis showed that the differentially expressed genes (DEGs) between homozygous mutants and wild-type individuals were enriched in cytoskeleton-related terms, and a KEGG enrichment analysis showed that the upregulated DEGs between homozygous mutants and wild-type individuals were enriched in the phagosome and apoptosis pathways. These results indicated that apoptosis was activated prematurely in the PSGs of homozygous mutants. Furthermore, autophagy and heat shock response were activated in the PSGs of homozygous mutants, as demonstrated by an analysis of the DEGs related to autophagy and heat shock. A comparative proteomic analysis further confirmed that autophagy, apoptosis and the heat shock response were activated in the PSGs of homozygous mutants, which led to premature degradation of the PSGs. These results provide insights for obtaining a more in-depth understanding of the mechanism of silk secretion in silkworms.

Calpain-calpastatin system and cancer progression

The calpain system is required by many important physiological processes, including the cell cycle, cytoskeleton remodelling, cellular proliferation, migration, cancer cell invasion, metastasis, survival, autophagy, apoptosis and signalling, as well as the pathogenesis of a wide range of disorders, in which it may function to promote tumorigenesis. Calpains are intracellular conserved calcium-activated neutral cysteine proteinases that are involved in mediating cancer progression via catalysing and regulating the proteolysis of their specific substrates, which are important signalling molecules during cancer progression. μ-calpain, m-calpain, and their specific inhibitor calpastatin are the three molecules originally identified as comprising the calpain system and they contain several crucial domains, specific motifs, and functional sites. A large amount of data supports the roles of the calpain-calpastatin system in cancer progression via regulation of cellular adhesion, proliferation, invasion, metastasis, and cellular survival and death, as well as inflammation and angiogenesis during tumorigenesis, implying that the inhibition of calpain activity may be a potential anti-cancer intervention strategy targeting cancer cell survival, invasion and chemotherapy resistance.

Neuroprotection offered by mesenchymal stem cells in perinatal brain injury: Role of mitochondria, inflammation, and reactive oxygen species

Preclinical studies have shown that mesenchymal stem cells have a positive effect in perinatal brain injury models. The mechanisms that cause these neurotherapeutic effects are not entirely intelligible. Mitochondrial damage, inflammation, and reactive oxygen species are considered to be critically involved in the development of injury. Mesenchymal stem cells have immunomodulatory action and exert mitoprotective effects which attenuate production of reactive oxygen species and promote restoration of tissue function and metabolism after perinatal insults. This review summarizes the present state, the underlying causes, challenges and possibilities for effective clinical translation of mesenchymal stem cell therapy.

Pathophysiology, Biomarkers, and Therapeutic Modalities Associated with Skeletal Muscle Loss Following Spinal Cord Injury

A spinal cord injury (SCI) may lead to loss of strength, sensation, locomotion and other body functions distal to the lesion site. Individuals with SCI also develop secondary conditions due to the lack of skeletal muscle activity. As SCI case numbers increase, recent studies have attempted to determine the best options to salvage affected musculature before it is lost. These approaches include pharmacotherapeutic options, immunosuppressants, physical activity or a combination thereof. Associated biomarkers are increasingly used to determine if these treatments aid in the protection and reconstruction of affected musculature.

Dapsone prolong delayed excitotoxic neuronal cell death by interacting with proapoptotic/survival signaling proteins

BACKGROUND

Dapsone prevents ischemic injury, inhibits apoptosis and shows functional improvement post-ischemia. However, its effect on proapoptotic or survival proteins in delayed ischemia remains unclear.

METHODS

Male adult Wistar rats were subjected to middle cerebral artery occlusion (MCAO) for 90 min followed by 24 h of ischemic reperfusion (I/R). Dapsone [9.375 or 12.5 mg/kg, intraperitoneally (IP)] was administered at 3, 6 and 12 h of I/R followed by behavioural assessment, brain infarction, histological alteration and cell viability study. Further, dapsone (25 and 50 µM) was added at 3, 6 and 12 h after L-glutamate (100 µM) in primary cortical culture (DIV 14) and cell viability, cytotoxicity, apoptosis was observed. Proteins expression were observed using immunocytochemistry. All experiments were performed after 24 h of I/R (In-Vivo) and 24 h of recovery post glutamate insult (In-Vitro).

RESULTS

Reduced brain infarction, improved neurobehavioural functions in addition to reduction in abnormal morphological structures of ischemic brain and improvement in cell viability was observed with treatment of dapsone (12.5 mg/kg) administered upto 6 h. Similarly, dapsone (25, 50 µM) increased cell survival post glutamate insult in cortical culture (In-vitro). Further, dapsone treatment at delayed hours (6 h) reduced apoptotic nuclei and proapoptotic proteins JNK, PTEN, Calpain, Caspase 3 expression along with activation of prosurvival protein BDNF expression post-glutamate insult.

CONCLUSION

Our results suggest that dapsone has the potential to limit the neuronal damage post-glutamate insult in delayed hours (6 h) through repressing proapoptotic proteins JNK, PTEN, Calpain, Caspase-3 of cerebral ischemia along with activation of pro-survival protein BDNF.

Effects of p38 MAPK signaling pathway on cognitive function and recovery of neuronal function after hypoxic-ischemic brain injury in newborn rats

To explore the effects of p38 MAPK signaling pathway on cognitive function and recovery of neuronal function after hypoxic-ischemic brain injury (HIBI) in newborn rats. Seventy-two healthy SPF grade SD newborn rats were randomly and equally divided into Normal group (healthy rats) and Sham group (rats underwent sham operation), Model group (HIBI model rats), p38 MAPK Inhibitor group (HIBI model rats treated with p38 MAPK inhibitor) and p38 MAPK Activator group (HIBI model rats treated with p38 MAPK activator). On postnatal day 28, Morris water maze, tail suspension test and inclined plane test were conducted on rats in each group. Twenty-four hours after modeling, the expression of p-p38 MAPK protein and apoptosis related genes in rat hippocampal tissues was detected by TUNEL staining, qRT-PCR and Western blot. Compared with Normal group, escape latency and inclined plane test time were prolonged, the number of passing through the platform and tail suspension time were reduced (all P < 0.05); Bax and Caspase-3 mRNA and protein expression levels and p-p38 MAPK protein level were increased, Bcl-2 mRNA level was decreased, and neuronal apoptosis proportion was increased in Model group (all P < 0.05). Compared with Model group, the above indicators showed reversed and enhanced trends in p38 MAPK Inhibitor and p38 MAPK Activator groups, respectively (all P < 0.05). Inhibition of p38 MAPK signaling pathway can effectively improve the learning and memory ability and motor function of newborn rats with HIBI, and reduce neuronal apoptosis in the hippocampal tissues, thereby promoting neuronal recovery.

Autophagy in neurodegeneration: New insights underpinning therapy for neurological diseases

In autophagy long-lived proteins, protein aggregates or damaged organelles are engulfed by vesicles called autophagosomes prior to lysosomal degradation. Autophagy dysfunction is a hallmark of several neurodegenerative diseases in which misfolded proteins or dysfunctional mitochondria accumulate. Excessive autophagy can also exacerbate brain injury under certain conditions. In this review, we provide specific examples to illustrate the critical role played by autophagy in pathological conditions affecting the brain and discuss potential therapeutic implications. We show how a singular type of autophagy-dependent cell death termed autosis has attracted attention as a promising target for improving outcomes in perinatal asphyxia and hypoxic-ischaemic injury to the immature brain. We provide evidence that autophagy inhibition may be protective against radiotherapy-induced damage to the young brain. We describe a specialized form of macroautophagy of therapeutic relevance for motoneuron and neuromuscular diseases, known as chaperone-assisted selective autophagy, in which heat shock protein B8 is used to deliver aberrant proteins to autophagosomes. We summarize studies pinpointing mitophagy mediated by the serine/threonine kinase PINK1 and the ubiquitin-protein ligase Parkin as a mechanism potentially relevant to Parkinson's disease, despite debate over the physiological conditions in which it is activated in organisms. Finally, with the example of the autophagy-inducing agent rilmenidine and its discrepant effects in cell culture and mouse models of motor neuron disorders, we illustrate the importance of considering aspects such a disease stage and aggressiveness, type of insult and load of damaged or toxic cellular components, when choosing the appropriate drug, timepoint and duration of treatment.

Apoptotic Markers in the Midbrain of the Human Neonate After Perinatal Hypoxic/Ischemic Injury

Our previous postmortem studies on neonates with neuropathological injury of perinatal hypoxia/ischemia (PHI) showed a dramatic reduction of tyrosine hydroxylase expression (dopamine synthesis enzyme) in substantia nigra (SN) neurons, with reduction of their cellular size. In order to investigate if the above observations represent an early stage of SN degeneration, we immunohistochemically studied the expression of cleaved caspase-3 (CCP3), apoptosis inducing factor (AIF), and DNA fragmentation by using terminal deoxynucleotidyltransferase-mediated dUTP-biotin 3'-end-labeling (TUNEL) technique in the SN of 22 autopsied neonates (corrected age ranging from 34 to 46.5 gestational weeks), in relation to the severity/duration of PHI injury, as estimated by neuropathological criteria. No CCP3-immunoreactive neurons and a limited number of apoptotic TUNEL-positive neurons with pyknotic characteristics were found in the SN. Nuclear AIF staining was revealed only in few SN neurons, indicating the presence of early signs of AIF-mediated degeneration. By contrast, motor neurons of the oculomotor nucleus showed higher cytoplasmic AIF expression and nuclear translocation, possibly attributed to the combined effect of developmental processes and increased oxidative stress induced by antemortem and postmortem factors. Our study indicates the activation of AIF, but not CCP3, in the SN and oculomotor nucleus of the human neonate in the developmentally critical perinatal period.

Puerarin attenuates hypoxia-resulted damages in neural stem cells by up-regulating microRNA-214

Puerarin has been reported to be useful in protection against hypoxia-induced injury. In our current study, we attempted to explore the protective effects of puerarin against hypoxia-caused damages in neural stem cells (NSCs). Additionally, the relative molecular underpinning studies preliminarily proceeded. NSCs were pre-incubated with puerarin before the hypoxic stimulus. MicroRNA-214 (miR-214) inhibitor was transfected into NSCs. Subsequently, the viability of NSCs was assessed by CCK-8 assay. Flow cytometry was employed to detect apoptotic cells after staining. qRT-PCR was performed to quantify miR-214. Western blot was applied for analyzing the expression of apoptosis-relative proteins and regulators. We found that puerarin alleviated hypoxia-induced apoptosis and maintained cell viability. Hypoxia-evoked up-regulation of miR-214 was further enhanced by puerarin. By contrast, miR-214-deficient NSCs showed the reduction in cell viability and the facilitation in apoptosis progress after pre-treatment with puerarin and stimulation in a hypoxia circumstance. Additionally, puerarin restored the phosphorylation of relative regulators, which was originally blunted by hypoxia. However, puerarin did not evidently restore the phosphorylation for response to hypoxia in miR-214-silenced NSCs. In conclusion, puerarin might be applied as a novel agent to ameliorate hypoxia-evoked damages in NSCs. Molecularly, miR-214 might be implicated in the protective roles of puerarin.

Geniposide attenuates neonatal mouse brain injury after hypoxic-ischemia involving the activation of PI3K/Akt signaling pathway

Perinatal hypoxic-ischemia (HI) is a leading cause of acute mortality and neurologic complications in newborns. Geniposide, a natural product extracted from the herb Gardenia jasminoides, has been shown to possess neuroprotective effects in neurologic deficits. This study aims to investigate whether Geniposide has therapeutic potential to HI brain injury and the underlying mechanisms. C57/bl6 mice were subjected to HI insult on postnatal day 10. Geniposide (20 mg/kg b.w.) was administered intragastrically every day after HI insult for 7 successional days. Then mice at P18 were sacrificed and brain tissues were collected for further analysis. Geniposide treatment significantly inhibited cell apoptosis, reduced serum IgG leakage into brain tissue, attenuated astrogliosis and microgliosis, prevented loss of pericytes, loss of tight junction and adherens junction proteins. The PI3K/Akt signaling pathway, which related proteins were downregulated after HI insult, was activated by Geniposide treatment. Geniposide treatment after neonatal HI insult attenuated HI-induced cell apoptosis, IgG leakage, microgliosis, astrogliosis, pericytes loss and junction protein degradation. Geniposide could protect against HI-induced brain injury, which might be through the activation of PI3K/Akt signaling pathway.

Focal Cerebral Ischemia and Reperfusion Induce Brain Injury Through α2δ-1-Bound NMDA Receptors

Background and Purpose- Glutamate NMDARs (N-methyl-D-aspartate receptors) play a major role in the initiation of ischemic brain damage. However, NMDAR antagonists have no protective effects in stroke patients, possibly because they impair physiological functions of NMDARs. α2δ-1 (encoded by Cacna2d1) is strongly expressed in many brain regions. We determined the contribution of α2δ-1 to NMDAR hyperactivity and brain injury induced by ischemia and reperfusion. Methods- Mice were subjected to 90 minutes of middle cerebral artery occlusion followed by 24 hours of reperfusion. Neurological deficits, brain infarct volumes, and calpain/caspase-3 activity in brain tissues were measured. NMDAR activity of hippocampal CA1 neurons was measured in an in vitro ischemic model. Results- Middle cerebral artery occlusion increased α2δ-1 protein glycosylation in the cerebral cortex, hippocampus, and striatum. Coimmunoprecipitation showed that ischemia rapidly enhanced the α2δ-1-NMDAR physical interaction in the mouse brain tissue. Inhibiting α2δ-1 with gabapentin, uncoupling the α2δ-1-NMDAR interaction with an α2δ-1 C terminus-interfering peptide, or genetically ablating Cacna2d1 had no effect on basal NMDAR currents but strikingly abolished oxygen-glucose deprivation-induced NMDAR hyperactivity in hippocampal CA1 neurons. Systemic treatment with gabapentin or α2δ-1 C-terminus-interfering peptide or Cacna2d1 genetic knock-out reduced middle cerebral artery occlusion-induced infarct volumes, neurological deficit scores, and calpain/caspase-3 activation in brain tissues. Conclusions- α2δ-1 is essential for brain ischemia-induced neuronal NMDAR hyperactivity, and α2δ-1-bound NMDARs mediate brain damage caused by cerebral ischemia. Targeting α2δ-1-bound NMDARs, without impairing physiological α2δ-1-free NMDARs, may be a promising strategy for treating ischemic stroke.

The Long-Term Impairment in Redox Homeostasis Observed in the Hippocampus of Rats Subjected to Global Perinatal Asphyxia (PA) Implies Changes in Glutathione-Dependent Antioxidant Enzymes and TIGAR-Dependent Shift Towards the Pentose Phosphate Pathways: Effect of Nicotinamide

We have recently reported that global perinatal asphyxia (PA) induces a regionally sustained increase in oxidized glutathione (GSSG) levels and GSSG/GSH ratio, a decrease in tissue-reducing capacity, a decrease in catalase activity, and an increase in apoptotic caspase-3-dependent cell death in rat neonatal brain up to 14 postnatal days, indicating a long-term impairment in redox homeostasis. In the present study, we evaluated whether the increase in GSSG/GSH ratio observed in hippocampus involves changes in glutathione reductase (GR) and glutathione peroxidase (GPx) activity, the enzymes reducing glutathione disulfide (GSSG) and hydroperoxides, respectively, as well as catalase, the enzyme protecting against peroxidation. The study also evaluated whether there is a shift in the metabolism towards the penthose phosphate pathway (PPP), by measuring TIGAR, the TP53-inducible glycolysis and apoptosis regulator, associated with delayed cell death, further monitoring calpain activity, involved in bax-dependent cell death, and XRCC1, a scaffolding protein interacting with genome sentinel proteins. Global PA was induced by immersing fetus-containing uterine horns removed by a cesarean section from on term rat dams into a water bath at 37 °C for 21 min. Asphyxia-exposed and sibling cesarean-delivered fetuses were manually resuscitated and nurtured by surrogate dams. Animals were euthanized at postnatal (P) days 1 or 14, dissecting samples from hippocampus to be assayed for glutathione, GR, GPx (all by spectrophotometry), catalase (Western blots and ELISA), TIGAR (Western blots), calpain (fluorescence), and XRCC1 (Western blots). One hour after delivery, asphyxia-exposed and control neonates were injected with either 100 μl saline or 0.8 mmol/kg nicotinamide, i.p., shown to protect from the short- and long-term consequences of PA. It was found that global PA produced (i) a sustained increase of GSSG levels and GSSG/GSH ratio at P1 and P14; (ii) a decrease of GR, GPx, and catalase activity at P1 and P14; (iii) a decrease at P1, followed by an increase at P14 of TIGAR levels; (iv) an increase of calpain activity at P14; and (v) an increase of XRCC1 levels, but only at P1. (vi) Nicotinamide prevented the effect of PA on GSSG levels and GSSG/GSH ratio, and on GR, GPx, and catalase activity, also on increased TIGAR levels and calpain activity observed at P14. The present study demonstrates that the long-term impaired redox homeostasis observed in the hippocampus of rats subjected to global PA implies changes in GR, GPx, and catalase, and a shift towards PPP, as indicated by an increase of TIGAR levels at P14.

Photobiomodulation preconditioning prevents cognitive impairment in a neonatal rat model of hypoxia-ischemia

Neonatal hypoxia-ischemia (HI) injury caused by oxygen deprivation is the most common cause of mortality and severe neurologic deficits in neonates. The present work evaluated the preventative effect of photobiomodulation (PBM) preconditioning, and its underlying mechanism of action on brain damage in an HI model in neonatal rats. According to the optimal time response of ATP levels in brain samples removed from normal rats, a PBM preconditioning (PBM-P) regimen (808 nm CW laser, 1 cm2 spot, 100 mW/cm2 , 12 J/cm2 ) was delivered to the scalp 6 hours before HI. PBM-P significantly attenuated cognitive impairment, volume shrinkage in the brain, neuron loss, dendritic and synaptic injury after HI. Further mechanistic investigation found that PBM-P could restore HI-induced mitochondrial dynamics and inhibit mitochondrial fragmentation, followed by a robust suppression of cytochrome c release, and prevention of neuronal apoptosis by inhibition of caspase activation. Our work suggests that PBM-P can attenuate HI-induced brain injury by maintaining mitochondrial dynamics and inhibiting the mitochondrial apoptotic pathway.

Extracellular Vesicles Derived from Wharton's Jelly Mesenchymal Stem Cells Prevent and Resolve Programmed Cell Death Mediated by Perinatal Hypoxia-Ischemia in Neuronal Cells

Hypoxic-ischemic (HI) insult in the perinatal phase harbors a high risk of encephalopathy in the neonate. Brain cells undergo apoptosis, initiating neurodegeneration. So far, therapeutic approaches such as cooling remain limited. Transplantation of mesenchymal stem cells (MSCs) exhibits therapeutic success despite the short-time survival in the host brain, providing strong evidence that their beneficial effects are largely based on secreted factors, including extracellular vesicles (EVs). The aim of this study was to investigate the effects of human Wharton’s jelly MSC (hWJ-MSC)-derived EVs on neuroprotection and neuroregeneration, using an in vitro model of oxygen–glucose deprivation/reoxygenation (OGD/R) mimicking HI injury in the mouse neuroblastoma cell line neuro2a (N2a). hWJ-MSC-derived EVs were isolated from cell culture supernatants by multistep centrifugation and identified by endosomal marker expression and electron microscopy. OGD/R significantly increased DNA fragmentation and caspase 3 (Casp3) transcription in N2a cells relative to undamaged cells. OGD/R-mediated DNA fragmentation and Casp3 expression could be prevented as well as resolved by the addition of hWJ-MSC-derived EV before and after OGD, respectively. hWJ-MSC-derived EV also tended to increase the phosphorylation of the B cell lymphoma 2 (Bcl2) family member Bcl-2-antagonist of cell death (BAD) in N2a cells, when added prior or post OGD, thereby inactivating the proapoptotic function of BAD. Fluorescence confocal microscopy revealed the close localization of hWJ-MSC-derived EVs to the nuclei of N2a cells. Furthermore, EVs released their RNA content into the cells. The expression levels of the microRNAs (miRs) let-7a and let-7e, known regulators of Casp3, were inversely correlated to Casp3. Our data suggest that hWJ-MSC-derived EVs have the potential to prevent and resolve HI-induced apoptosis in neuronal cells in the immature neonatal brain. Their antiapoptotic effect seems to be mediated by the transfer of EV-derived let-7-5p miR.

Panax ginseng components and the pathogenesis of Alzheimer's disease (Review)

Ginseng is one of the main representatives of traditional Chinese medicine and presents a wide range of pharmacological actions. Ginsenosides are the main class of active compounds found in ginseng. They demonstrate unique biological activity and medicinal value, namely anti-tumour, anti-inflammatory and antioxidant properties, as well as anti-apoptotic properties. Increasing levels of stress in life are responsible for the increased incidence of nervous system diseases. Neurological diseases create a huge burden on the lives and health of individuals. In recent years, studies have indicated that ginsenosides play a pronounced positive role in the prevention and treatment of neurological diseases. Nevertheless, research is still at an early stage of development, and the complex mechanisms of action involved remain largely unknown. This review aimed to shed light into what is currently known about the mechanisms of action of ginsenosides in relation to Alzheimer's disease. Scientific material and theoretical bases for the treatment of nervous system diseases with purified Panax ginseng extracts are also discussed.

Bestrophin-3 Expression in a Subpopulation of Astrocytes in the Neonatal Brain After Hypoxic-Ischemic Injury

Bestrophin-3, a potential candidate for a calcium-activated chloride channel, recently was suggested to have cell-protective functions. We studied the expression and alternative splicing of bestrophin-3 in neonatal mouse brain and after hypoxic-ischemic (HI) injury and in human neonatal brain samples. HI brain injury was induced in 9-day old mice by unilateral permanent common carotid artery occlusion in combination with exposure to 10% oxygen for 50 min. Endoplasmic reticulum stress was induced by thapsigargin treatment in primary culture of mouse brain astrocytes. We also investigated expression of bestrophin-3 protein in a sample of human neonatal brain tissue. Bestrophin-3 protein expression was detected with immunohistochemical methods and western blot; mRNA expression and splicing were analyzed by RT-PCR. HI induced a brain tissue infarct and a pronounced increase in the endoplasmic reticulum-associated marker CHOP. Three days after HI a population of astrocytes co-expressed bestrophin-3 and nestin in a penumbra-like area of the injured hemisphere. However, total levels of Bestrophin-3 protein in mouse cortex were reduced after injury. Mouse astrocytes in primary culture also expressed bestrophin-3 protein, the amount of which was reduced by endoplasmic reticulum stress. Bestrophin-3 protein was detected in astrocytes in the hippocampal region of the human neonatal brain which had patchy white matter gliosis and neuronal loss in the Sommer’s sector of the Ammon’s horn (CA1). Analysis of bestrophin-3 mRNA in mouse brain with and without injury showed the presence of two truncated spliced variants, but no full-length mRNA. Total amount of bestrophin-3 mRNA increased after HI, but showed only minor injury-related change. However, the splice variants of bestrophin-3 mRNA were differentially regulated after HI depending on the presence of tissue injury. Our results show that bestrophin-3 is expressed in neonatal mouse brain after injury and in the human neonatal brain with pathology. In mouse brain bestrophin-3 protein is upregulated in a specific astrocyte population after injury and is co-expressed with nestin. Splice variants of bestrophin-3 mRNA respond differently to HI, which might indicate their different roles in tissue injury.

Alterations of hippocampal neurogenesis during development of Alzheimer's disease-like pathology in OXYS rats

Neurogenesis is the key mechanism of neuronal plasticity in the adult mammalian brain. Alterations of neurogenesis happen concurrently with (and contribute to) development and progression of numerous neuropathological conditions including Alzheimer's disease (AD). Being the most common type of dementia, AD is studied extensively; however, the data concerning changes in neurogenesis in the pathogenesis of this disease are inconsistent. Here, using OXYS rats as a suitable model of the most common (sporadic) form of AD, we examined neurogenesis in the hippocampal dentate gyrus in early ontogenesis prior to appearance of any signs of neurodegeneration and during development and progression of AD-like pathology. We demonstrated retardation of hippocampal development in OXYS rats at an early age; this problem may contribute to the emergence of AD signs late in life. Manifestation and progression of AD-like pathology are accompanied by transcriptome changes affecting genes involved in neurogenesis in the hippocampus. These genes are associated with the extracellular matrix and angiogenesis; this observation points to alteration of a cellular microenvironment. This change along with an increased TrkA/p75^NTR ratio of nerve growth factor receptors in the hippocampus may contribute to increased density of immature neurons that we observed at the progressive stage of AD-like pathology in OXYS rats. These changes may be considered a compensatory reaction intended to slow down AD-associated neurodegeneration at the progressive stage of the disease. Collectively, these data suggest that alterations of neurogenesis may not only accompany the course of Alzheimer's disease but also play a causative role in this disorder.

Prolonged Exposure to Insulin Inactivates Akt and Erk1/2 and Increases Pancreatic Islet and INS1E β-Cell Apoptosis

Chronic hyperinsulinemia, in vivo, increases the resistance of peripheral tissues to insulin by desensitizing insulin signaling. Insulin, in a heterologous manner, can also cause IGF-1 resistance. The aim of the current study was to investigate whether insulin-mediated insulin and IGF-1 resistance develops in pancreatic β-cells and whether this resistance results in β-cell decompensation. Chronic exposure of rat islets or INS1E β-cells to increasing concentrations of insulin decreased Akt^S473 phosphorylation in response to subsequent acute stimulation with 10 nM insulin or IGF-1. Prolonged exposure to high insulin levels not only inhibited Akt^S473 phosphorylation, but it also resulted in a significant inhibition of the phosphorylation of P70S6 kinase and Erk_1/2 phosphorylation in response to the acute stimulation by glucose, insulin, or IGF-1. Decreased activation of Akt, P70S6K, and Erk_1/2 was associated with decreased insulin receptor substrate 2 tyrosine phosphorylation and insulin receptor β-subunit abundance; neither IGF receptor β-subunit content nor its phosphorylation were affected. These signaling impairments were associated with decreased SERCA2 expression, perturbed plasma membrane calcium current and intracellular calcium handling, increased endoplasmic reticulum stress markers such as eIF2α^S51 phosphorylation and Bip (GRP78) expression, and increased islet and β-cell apoptosis. We demonstrate that prolonged exposure to high insulin levels induces not only insulin resistance, but in a heterologous manner causes resistance to IGF-1 in rat islets and insulinoma cells resulting in decreased cell survival. These findings suggest the possibility that chronic exposure to hyperinsulinemia may negatively affect β-cell mass by increasing β-cell apoptosis.

Regionally Impaired Redox Homeostasis in the Brain of Rats Subjected to Global Perinatal Asphyxia: Sustained Effect up to 14 Postnatal Days

The present report evaluates the effect of global perinatal asphyxia on several parameters of oxidative stress and cell viability in rat brain tissue sampled at an extended neonatal period up to 14 days, a period characterised by intensive neuritogenesis, synaptogenesis, synaptic consolidation, pruning and delayed cell death. Perinatal asphyxia was induced by immersing foetus-containing uterine horns removed by a caesarean section from on term rat dams into a water bath at 37 °C for 21 min. Asphyxia-exposed and sibling caesarean-delivered foetuses were manually resucitated and nurtured by surrogate dams for 1 to 14 postnatal (P) days. Brain samples (mesencephalon, telencephalon and hippocampus) were assayed for glutathione (reduced and oxidated levels; spectrophotometry), tissue reducing capacity (potassium ferricyanide reducing assay, FRAP), catalase (the key enzyme protecting against oxidative stress and reactive oxygen species, Western blots and ELISA) and cleaved caspase-3 (the key executioner of apoptosis, Western blots) levels. It was found that global PA produced a regionally specific and sustained increase in GSSG/GSH ratio, a regionally specific decrease in tissue reducing capacity and a regionally and time specific decrease of catalase activity and increase of cleaved caspase-3 levels. The present study provides evidence for regionally impaired redox homeostasis in the brain of rats subjected to global PA, an effect observed up to P14, mainly affecting mesencephalon and hippocampus, suggesting a sustained oxidative stress after the posthypoxia period. The oxidative stress observed postnatally can in part be associated to a respiratory apneic-like deficit, since there was a statistically significant decrease in respiration frequency in AS compared to CS neonates, also up to P14, together with the signs of a decreased peripheral blood perfusion (pink-blue skin colour in AS, compared to the pink colour observed in all CS neonates). It is proposed that PA implies a long-term metabolic insult, triggered by the length of hypoxia, the resuscitation/reoxigenation manoevres, but also by the developmental stage of the affected brain regions, and the integrity of cardiovascular and respiratory physiological functions, which are fundamental for warrantying a proper development.

Furin inhibitor protects against neuronal cell death induced by activated NMDA receptors

The proprotein convertases (PCs) act as serine proteases and are known to convert diverse precursor proteins into their active forms. Among the PCs, furin has been considered to play a crucial role not only in embryogenesis, but also in the initiation and progression of certain pathologic conditions. However, the roles played by furin with respect to neuronal cell injuries remain to be determined. An excessive influx of Ca²⁺ through the N-methyl-d-aspartate (NMDA) receptor has been associated with diverse neurological and neurodegenerative disorders. The aim of this study was to achieve further insight into the pathophysiologic roles of furin in cultured cortical neurons. We demonstrated that furin inhibitors dose-dependently prevented neuronal injury induced by NMDA treatment. Neuronal injury induced by NMDA treatment was attenuated by the calpain inhibitor calpeptin. And the increase observed in the activity of calpain after NMDA treatment was significantly inhibited by these furin inhibitors. Furthermore, calpain-2 activity, which was evaluated by means of the immunoblotting assay, was increased by NMDA treatment. It was noteworthy that this increased activity was almost completely inhibited by a furin inhibitor. Our findings suggested that furin is involved in NMDA-induced neuronal injury by acting upstream of calpain.

Intracellular Desmoglein-2 cleavage sensitizes epithelial cells to apoptosis in response to pro-inflammatory cytokines

Desmosomal cadherins mediate intercellular adhesion and have also been shown to regulate homeostatic signaling in epithelial cells. We have previously reported that select pro-inflammatory cytokines induce Dsg2 ectodomain cleavage and shedding from intestinal epithelial cells (IECs). Dsg2 extracellular cleaved fragments (Dsg2 ECF) function to induce paracrine pro-proliferative signaling in epithelial cells. In this study, we show that exposure of IECs to pro-inflammatory cytokines interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α) resulted in Dsg2 intracellular cleavage and generation of a ~55 kDa fragment (Dsg2 ICF). Dsg2 intracellular cleavage is mediated by caspase-8 and occurs prior to Dsg2 extracellular cleavage and the execution of apoptosis. Expression of exogenous Dsg2 ICF in model IECs resulted in increased sensitivity to apoptotic stimuli and apoptosis execution. Additionally, expression of the Dsg2 ICF repressed the anti-apoptotic Bcl-2 family member proteins Bcl-X_L and Mcl1. Taken together, our findings identify a novel mechanism by which pro-inflammatory mediators induce modification of Dsg2 to activate apoptosis and eliminate damaged cells, while also promoting release of Dsg2 ECF that promotes proliferation of neighboring cells and epithelial barrier recovery.

Combination of Constraint-Induced Movement Therapy with Electroacupuncture Improves Functional Recovery following Neonatal Hypoxic-Ischemic Brain Injury in Rats

Aim

Neonatal hypoxic-ischemia (HI) due to insufficient oxygen supply and blood flow during the prenatal and postnatal periods can cause cerebral palsy, a serious developmental condition. The purpose of this study was to investigate the efficacy of combining constraint-induced movement therapy (CIMT) and electroacupuncture to treat rat neonatal HI brain injury.

Methods

The left common carotid arteries of postnatal day 7 rats were ligated to induce HI brain injury, and the neonates were kept in a hypoxia chamber containing 8% oxygen for 2 hrs. Electroacupuncture at Baihui (GV 20) and Zusanli (ST 36) was performed concurrently with CIMT 3 weeks after HI induction for 4 weeks.

Results

Motor asymmetry after HI was significantly improved in the CIMT and electroacupuncture combination group, but HI lesion size was not improved. The combination of CIMT and electroacupuncture after HI injury increases NeuN and decreases GFAP levels in the cerebral cortex, suggesting that this combination treatment inversely regulates neurons and astrocytes. In addition, the combination treatment group reduced the level of cleaved caspase-3, a crucial mediator of apoptosis, in the cortex.

Conclusions

Our findings indicate that a combination of CIMT and electroacupuncture is an effective method to treat hemiplegia due to neonatal HI brain injury.

Mitochondrial Division Inhibitor 1 (mdivi-1) Protects Neurons against Excitotoxicity through the Modulation of Mitochondrial Function and Intracellular Ca2+ Signaling

Excessive dynamin related protein 1 (Drp1)-triggered mitochondrial fission contributes to apoptosis under pathological conditions and therefore it has emerged as a promising therapeutic target. Mitochondrial division inhibitor 1 (mdivi-1) inhibits Drp1-dependent mitochondrial fission and is neuroprotective in several models of brain ischemia and neurodegeneration. However, mdivi-1 also modulates mitochondrial function and oxidative stress independently of Drp1, and consequently the mechanisms through which it protects against neuronal injury are more complex than previously foreseen. In this study, we have analyzed the effects of mdivi-1 on mitochondrial dynamics, Ca²⁺ signaling, mitochondrial bioenergetics and cell viability during neuronal excitotoxicity in vitro. Time-lapse fluorescence microscopy revealed that mdivi-1 blocked NMDA-induced mitochondrial fission but not that triggered by sustained AMPA receptor activation, showing that mdivi-1 inhibits excitotoxic mitochondrial fragmentation in a source specific manner. Similarly, mdivi-1 strongly reduced NMDA-triggered necrotic-like neuronal death and, to a lesser extent, AMPA-induced toxicity. Interestingly, neuroprotection provided by mdivi-1 against NMDA, but not AMPA, correlated with a reduction in cytosolic Ca²⁺ ([Ca²⁺]_cyt) overload and calpain activation indicating additional cytoprotective mechanisms. Indeed, mdivi-1 depolarized mitochondrial membrane and depleted ER Ca²⁺ content, leading to attenuation of mitochondrial [Ca²⁺] increase and enhancement of the integrated stress response (ISR) during NMDA receptor activation. Finally, lentiviral knockdown of Drp1 did not rescue NMDA-induced mitochondrial fission and toxicity, indicating that neuroprotective activity of mdivi-1 is Drp1-independent. Together, these results suggest that mdivi-1 induces a Drp1-independent protective phenotype that prevents predominantly NMDA receptor-mediated excitotoxicity through the modulation of mitochondrial function and intracellular Ca²⁺ signaling.

Dichloroacetate treatment improves mitochondrial metabolism and reduces brain injury in neonatal mice

The purpose of this study was to evaluate the effect of dichloroacetate (DCA) treatment for brain injury in neonatal mice after hypoxia ischemia (HI) and the possible molecular mechanisms behind this effect. Postnatal day 9 male mouse pups were subjected to unilateral HI, DCA was injected intraperitoneally immediately after HI, and an additional two doses were administered at 24 h intervals. The pups were sacrificed 72 h after HI. Brain injury, as indicated by infarction volume, was reduced by 54.2% from 10.8 ± 1.9 mm³ in the vehicle-only control group to 5.0 ± 1.0 mm³ in the DCA-treated group at 72 h after HI (p = 0.008). DCA treatment also significantly reduced subcortical white matter injury as indicated by myelin basic protein staining (p = 0.018). Apoptotic cell death in the cortex, as indicated by counting the cells that were positive for apoptosis-inducing factor (p = 0.018) and active caspase-3 (p = 0.021), was significantly reduced after DCA treatment. The pyruvate dehydrogenase activity and the amount of acetyl-CoA in mitochondria was significantly higher after DCA treatment and HI (p = 0.039, p = 0.024). In conclusion, DCA treatment reduced neonatal mouse brain injury after HI, and this appears to be related to the elevated activation of pyruvate dehydrogenase and subsequent increase in mitochondrial metabolism as well as reduced apoptotic cell death.

Effect of hypothermia on apoptosis in traumatic brain injury and hemorrhagic shock model

INTRODUCTION

The neuroprotective mechanisms of therapeutic hypothermia against trauma-related injury have not been fully understood yet. In this study, we aimed to investigate the effects of therapeutic hypothermia on biochemical and histopathological markers of apoptosis using Traumatic brain injury (TBI) and hemorrhagic shock (HS) model.

METHODS

A total of 50 male albino-wistar rats were divided into five groups: Group isolated TBI, Group NT (HT+HS+normothermia), Group MH (HT+HS+mild hypothermia), Group MoH (HT+HS+moderate hypothermia) and Group C (control). Neurological deficit scores were assessed at baseline and at 24h. The rats were, then, sacrificed to collect serum and brain tissue samples. Levels of Caspase-3,6,8, proteoglycan-4 (PG-4), malondialdehyde (MDA), and nitric oxide (NO) were measured in serum and brain tissue samples. Histopathological examination was performed in brain tissue.

RESULTS

There were significant differences in the serum levels of Caspase-3 between Group NT and Group C (p=0.018). The serum levels of Caspase-6 in Group NT (0.70±0.58) were lower than Group MH (1.39±0.28), although the difference was not statistically significant (p=0.068). There were significant differences in the brain tissue samples for Caspase-3 levels between Group NT and Group C (p=0.049). A significant difference in the Caspase-8 brain tissue levels was also observed between Group NT and Group C (p=0.022). Group NT had significantly higher scores of all the pathological variables (for edema p<0.017; for gliosis p<0.001; for congestion p<0.003, for hemorrhage p<0.011) than Group C.

CONCLUSION

Our study results suggest that hypothermia may exert its neuroprotective effects by reducing markers of apoptotic pathway, particularly Caspase-3 on TBI and HS.

Attenuated Superoxide Dismutase 2 Activity Induces Atherosclerotic Plaque Instability During Aging in Hyperlipidemic Mice

BACKGROUND

Atherosclerosis progression during aging culminates in the development of vulnerable plaques, which may increase the risk of cardiovascular events. Increased generation and/or decreased scavenging of reactive oxygen species in the vascular wall are major contributors to atherogenesis. We previously showed that superoxide dismutase 2 deficiency increased vascular oxidative stress and reduced aortic compliance in aged wild-type mice and that young Apoe-/-/Sod2+/- had increased mitochondrial DNA damage and atherosclerosis versus young Apoe-/- mice. Here we investigated the effects of superoxide dismutase 2 deficiency on atherosclerosis progression and plaque morphology in middle-aged Apoe-/- mice.

METHODS AND RESULTS

Compared with Apoe-/-, middle-aged Apoe-/-/Sod2+/- mice had increased vascular wall reactive oxygen species (P<0.05) and higher atherosclerotic lesion area (P<0.001). The atherosclerotic plaques in middle-aged Apoe-/-/Sod2+/- mice had an increased necrotic core with higher inflammatory cell infiltration, a thinned fibrous cap with depleted smooth muscle content, and intraplaque hemorrhage. In addition, the plaque shoulder area had higher levels of calpain-2, caspase-3, and matrix metalloproteinase-2 in intimal smooth muscle cells and depleted fibrous cap collagen. Targeting mitochondrial reactive oxygen species with MitoTEMPO attenuated features of atherosclerotic plaque vulnerability in middle-aged Apoe-/-/Sod2+/- mice by lowering expression of calpain-2, caspase-3, and matrix metalloproteinase-2 and decreasing smooth muscle cell apoptosis and matrix degradation.

CONCLUSIONS

Enhanced mitochondrial oxidative stress under hyperlipidemic conditions in aging induces plaque instability, in part by increasing smooth muscle cell apoptosis, necrotic core expansion, and matrix degradation. Targeting mitochondrial reactive oxygen species or its effectors may be a viable therapeutic strategy to prevent aging-associated and oxidative stress-related atherosclerosis complications.

Measurement of Elevated IL-37 Levels in Acute Ischemic Brain Injury: A Cross-sectional Pilot Study

Interleukin (IL)-37 is a new member of the IL-1 cytokine family with a defined role as a negative feedback inhibitor of proinflammatory responses. IL-37 has yet to be evaluated in non-immune-mediated neurological diseases, such as ischemic or hemorrhagic strokes. This study aimed to measure urine and serum IL-37 levels in patients with ischemic stroke. Twelve patients consented for our study. Two sets of serum and urine samples were obtained and analyzed, one upon admission to the hospital and the second the next morning. The trends in serum levels of IL- 37 in six stroke patients and the trends in the urine levels of eight stroke patients were measured by real-time polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). Our pilot study showed IL-37 levels in urine in stroke patients ranging between 210 and 4,534. Serum IL-37 levels were in the range of 44 - 5,235 in patients with ischemic stroke. Three patients who presented within three hours of stroke onset had IL-37 serum levels of 2,655 pg/ml, 3,517 pg/ml, and 5,235 pg/ml, respectively. In all others, it ranged much less than that, with the trend of delayed presentation giving lower IL-37 levels. The study shows a rather stable early elevation of serum IL-37 levels post-ischemic stroke. IL-37 plays a certain role in mediating post-stroke inflammation with a significant increase in serum levels of this novel cytokine observed in ischemic stroke patients. Further large-scale studies need to be done to establish its definite role. A prospective "CRISP" trial is registered with the ClinicalTrials.gov (Identifier: NCT03297827) to determine the role of IL-37 in modulating post-stroke inflammation.

NMNAT3 is protective against the effects of neonatal cerebral hypoxia-ischemia

Objective

To determine whether the NAD+ biosynthetic protein, nicotinamide mononucleotide adenylyltransferase‐3 (NMNAT3), is a neuroprotective inducible enzyme capable of decreasing cerebral injury after neonatal hypoxia‐ischemia (H‐I) and reducing glutamate receptor‐mediated excitotoxic neurodegeneration of immature neurons.

Methods

Using NMNAT3‐overexpressing mice we investigated whether increases in brain NMNAT3 reduced cerebral tissue loss following H‐I. We then employed biochemical methods from injured neonatal brains to examine the inducibility of NMNAT3 and the mechanism of NMNAT3‐dependent neuroprotection. Using AAV8‐mediated vectors for in vitro neuronal NMNAT3 knockdown, we then examine the endogenous role of this protein on immature neuronal survival prior and following NMDA receptor‐mediated excitotoxicity.

Results

NMNAT3 mRNA and protein levels increased after neonatal H‐I. In addition, NMNAT3 overexpression decreased cortical and hippocampal tissue loss 7 days following injury. We further show that the NMNAT3 neuroprotective mechanism involves a decrease in calpastatin degradation, and a decrease in caspase‐3 activity and calpain‐mediated cleavage. Conversely, NMNAT3 knockdown of cortical and hippocampal neurons in vitro caused neuronal degeneration and increased excitotoxic cell death. The neurodegenerative effects of NMNAT3 knockdown were counteracted by exogenous upregulation of NMNAT3.

Conclusions

Our observations provide new insights into the neuroprotective mechanisms of NMNATs in the injured developing brain, adding NMNAT3 as an important neuroprotective enzyme in neonatal H‐I via inhibition of apoptotic and necrotic neurodegeneration. Interestingly, we find that endogenous NMNAT3 is an inducible protein important for maintaining the survival of immature neurons. Future studies aimed at uncovering the mechanisms of NMNAT3 upregulation and neuroprotection may offer new therapies against the effects of hypoxic‐ischemic encephalopathy.

Cell Death in the Developing Brain after Hypoxia-Ischemia

Perinatal insults such as hypoxia–ischemia induces secondary brain injury. In order to develop the next generation of neuroprotective therapies, we urgently need to understand the underlying molecular mechanisms leading to cell death. The cell death mechanisms have been shown to be quite different in the developing brain compared to that in the adult. The aim of this review is update on what cell death mechanisms that are operating particularly in the setting of the developing CNS. In response to mild stress stimuli a number of compensatory mechanisms will be activated, most often leading to cell survival. Moderate-to-severe insults trigger regulated cell death. Depending on several factors such as the metabolic situation, cell type, nature of the stress stimulus, and which intracellular organelle(s) are affected, the cell undergoes apoptosis (caspase activation) triggered by BAX dependent mitochondrial permeabilzation, necroptosis (mixed lineage kinase domain-like activation), necrosis (via opening of the mitochondrial permeability transition pore), autophagic cell death (autophagy/Na⁺, K⁺-ATPase), or parthanatos (poly(ADP-ribose) polymerase 1, apoptosis-inducing factor). Severe insults cause accidental cell death that cannot be modulated genetically or by pharmacologic means. However, accidental cell death leads to the release of factors (damage-associated molecular patterns) that initiate systemic effects, as well as inflammation and (regulated) secondary brain injury in neighboring tissue. Furthermore, if one mode of cell death is inhibited, another route may step in at least in a scenario when upstream damaging factors predominate over protective responses. The provision of alternative routes through which the cell undergoes death has to be taken into account in the hunt for novel brain protective strategies.

Long Noncoding RNA AK12348 is Involved in the Regulation of Myocardial Ischaemia-Reperfusion Injury by Targeting PARP and Caspase-3

BACKGROUD

Recently long non-coding RNAs (lncRNAs) have attracted attention in several biomedical fields. The purpose of this study is to investigate the profile of myocardial lncRNAs and their potential roles in myocardial ischaemia-reperfusion injury (IRI).

METHODS

EdgeR bioconductor package was used to screen differentially expressed lncRNAs in myocardial IRI, and lncRNA AK12348 was selected. The mRNA levels of lncRNA AK12348 in normal and anoxia/reoxygenation (A/R) cardiomyocytes were determined by qRT-PCR. After transfection with siRNA-lncRNA, AK12348, LDH release and cell apoptotic rates in normal and A/R cardiomyocytes were determined. The protein expression values of PARP and Caspase-3 were also determined by western blotting.

RESULTS

The relative level of lncRNA AK12348, LDH release and cell apoptotic rate in A/R cardiomyocytes was significantly higher than that in normal cardiomyocytes. After transfection with siRNA-lncRNA AK12348, LDH release and cell apoptotic rates in A/R cardiomyocytes were reduced, while the values in normal cardiomyocytes had almost no change. The protein expression values of PARP and Caspase-3 in A/R cardiomyocytes were much higher than the Control. After knockdown of lncRNA AK12348, the values decreased.

CONCLUSION

Long non-coding RNAs AK12348 could be potential therapeutic targets for the treatment of myocardial IRI.

Haploinsufficiency in the mitochondrial protein CHCHD4 reduces brain injury in a mouse model of neonatal hypoxia-ischemia

Mitochondria contribute to neonatal hypoxic-ischemic brain injury by releasing potentially toxic proteins into the cytosol. CHCHD4 is a mitochondrial intermembrane space protein that plays a major role in the import of intermembrane proteins and physically interacts with apoptosis-inducing factor (AIF). The purpose of this study was to investigate the impact of CHCHD4 haploinsufficiency on mitochondrial function and brain injury after cerebral hypoxia-ischemia (HI) in neonatal mice. CHCHD4+/- and wild-type littermate mouse pups were subjected to unilateral cerebral HI on postnatal day 9. CHCHD4 haploinsufficiency reduced insult-related AIF and superoxide dismutase 2 release from the mitochondria and reduced neuronal cell death. The total brain injury volume was reduced by 21.5% at 3 days and by 31.3% at 4 weeks after HI in CHCHD4+/- mice. However, CHCHD4 haploinsufficiency had no influence on mitochondrial biogenesis, fusion, or fission; neural stem cell proliferation; or neural progenitor cell differentiation. There were no significant changes in the expression or distribution of p53 protein or p53 pathway-related genes under physiological conditions or after HI. These results suggest that CHCHD4 haploinsufficiency afforded persistent neuroprotection related to reduced release of mitochondrial intermembrane space proteins. The CHCHD4-dependent import pathway might thus be a potential therapeutic target for preventing or treating neonatal brain injury.

Molecular mechanisms of brain-derived neurotrophic factor in neuro-protection: Recent developments

Neuronal cell injury, as a consequence of acute or chronic neurological trauma, is a significant cause of mortality around the world. On a molecular level, the condition is characterized by widespread cell death and poor regeneration, which can result in severe morbidity in survivors. Potential therapeutics are of major interest, with a promising candidate being brain-derived neurotrophic factor (BDNF), a ubiquitous agent in the brain which has been associated with neural development and may facilitate protective and regenerative effects following injury. This review summarizes the available information on the potential benefits of BDNF and the molecular mechanisms involved in several pathological conditions, including hypoxic brain injury, stroke, Alzheimer's disease and Parkinson's disease. It further explores the methods in which BDNF can be applied in clinical and therapeutic settings, and the potential challenges to overcome.

Degradomics in Neurotrauma: Profiling Traumatic Brain Injury

Degradomics has recently emerged as a subdiscipline in the omics era with a focus on characterizing signature breakdown products implicated in various disease processes. Driven by promising experimental findings in cancer, neuroscience, and metabolomic disorders, degradomics has significantly promoted the notion of disease-specific "degradome." A degradome arises from the activation of several proteases that target specific substrates and generate signature protein fragments. Several proteases such as calpains, caspases, cathepsins, and matrix metalloproteinases (MMPs) are involved in the pathogenesis of numerous diseases that disturb the physiologic balance between protein synthesis and protein degradation. While regulated proteolytic activities are needed for development, growth, and regeneration, uncontrolled proteolysis initiated under pathological conditions ultimately culminates into apoptotic and necrotic processes. In this chapter, we aim to review the protease-substrate repertoires in neural injury concentrating on traumatic brain injury. A striking diversity of protease substrates, essential for neuronal and brain structural and functional integrity, namely, encryptic biomarker neoproteins, have been characterized in brain injury. These include cytoskeletal proteins, transcription factors, cell cycle regulatory proteins, synaptic proteins, and cell junction proteins. As these substrates are subject to proteolytic fragmentation, they are ceaselessly exposed to activated proteases. Characterization of these molecules allows for a surge of "possible" therapeutic approaches of intervention at various levels of the proteolytic cascade.