Effects of N-acetylcysteine amide (NACA), a novel thiol antioxidant against glutamate-induced cytotoxicity in neuronal cell line PC12

Protection of dauricine and daurisoline on PC12 cells damaged by glutamate or Aβ25-35

Glutamate (Glu) excitotoxicity and amyloid-β (Aβ) deposition are significant factors in the occurrence and development of Alzheimer's disease (AD). Dauricine and daurisoline are two alkaloid components of Menispermum dauricum DC. that have a protective effect on the nervous system. The protection of dauricine and daurisoline on Glu-injured PC12 cells and the protection dauricine on Aβ25-35-injured PC12 cells were investigated in this study. The results of the study demonstrated that on PC12 cells damaged by Glu (20 mM), dauricine and daurisoline (3 and 10 μM) increased the cell viability, reduced cell apoptosis, and enhanced mitochondrial membrane potential (MMP) levels. Dauricine and daurisoline can also reduce the levels of intracellular ROS and free Ca2+, and suppression the expression of CaM, p-CaMKII, and p-Tau in Glu-damaged PC12 cells. In addition, on PC12 cells damaged by Aβ25-35 (30 μM), dauricine (3 and 10 μM) can also significantly increase the cell viability and MMP levels, inhibit cell apoptosis, reduce intracellular ROS and free Ca2+ levels, and down-regulate protein expression of CaM, p-CaMKII, and p-Tau. This study demonstrates for the first time that dauricine and daurisoline may inhibit the excessive phosphorylation of Tau protein and subsequent cell apoptosis by suppressing the Ca2+-CaM/CaMKII pathway, thereby protecting PC12 cells damaged Glu or Aβ25-35in vitro. Dauricine and daurisoline have the potential to treat AD effectively and have further research value.

N-acetylcysteine amide and di- N-acetylcysteine amide protect retinal cells in culture via an antioxidant action

Reactive oxygen species (ROS) play a significant role in toxicity to the retina in a variety of diseases. N-acetylcysteine (NAC), N-acetylcysteine amide (NACA) and the dimeric di-N-acetylcysteine amide (diNACA) were evaluated in terms of protecting retinal cells, in vitro, in a variety of stress models. Three types of rat retinal cell cultures were utilized in the study: macroglial-only cell cultures, neuron-only retinal ganglion cell (RGC) cultures, and mixed cultures containing retinal glia and neurons. Ability of test agents to attenuate oxidative stress in all cultures was ascertained. In addition, capability of agents to protect against a variety of alternate clinically-relevant stressors, including excitotoxins and mitochondrial electron transport chain inhibitors, was also evaluated. Capacity of test agents to elevate cellular levels of reduced glutathione under normal and compromised conditions was also determined. NAC, NACA and diNACA demonstrated concentration-dependent cytoprotection against oxidative stress in all cultures. These three compounds, however, had differing effects against a variety of alternate insults to retinal cells. The most protective agent was NACA, which was most potent against the most stressors (including oxidative stress, mitochondrial impairment by antimycin A and azide, and glutamate-induced excitotoxicity). Similar to NAC, NACA increased glutathione levels in non-injured cells, although diNACA did not, suggesting a different, unknown mechanism of antioxidant activity for the latter. In support of this, diNACA was the only agent to attenuate rotenone-induced toxicity in mitochondria. NAC, NACA and diNACA exhibited varying degrees of antioxidant activity, i.e., protected cultured rat retinal cells from a variety of stressors which were designed to mimic aspects of the pathology of different retinal diseases. A general rank order of activity was observed: NACA ≥ diNACA > NAC. These results warrant further exploration of NACA and diNACA as antioxidant therapeutics for the treatment of retinal diseases, particularly those involving oxidative stress. Furthermore, we have defined the battery of tests carried out as the "Wood, Chidlow, Wall and Casson (WCWC) Retinal Antioxidant Indices"; we believe that these are of great value for screening molecules for potential to reduce retinal oxidative stress in a range of retinal diseases.

A Capsicum annuum L. seed extract exerts anti-neuroexcitotoxicity in HT22 hippocampal neurons

The hippocampal memory deficit stands out as a primary symptom in neurodegenerative diseases, including Alzheimer's disease. While numerous therapeutic candidates have been proposed, they primarily serve to delay disease progression. Given the irreversible brain atrophy or injury associated with these conditions, current research efforts are concentrated on preventive medicine strategies. Herein, we investigated whether the extracts of Capsicum annuum L. seeds (CSE) and Capsicum annuum L. pulp (CPE) have preventive properties against glutamate-induced neuroexcitotoxicity (one of the main causes of Alzheimer's disease) in HT22 hippocampal neuronal cells. Pretreatment with CSE demonstrated significant anti-neuroexcitotoxic activity, whereas CPE did not exhibit such effects. Specifically, CSE pretreatment dose-dependently inhibited the elevation of excitotoxic elements (intracellular calcium influx and reactive oxygen species; ROS) and apoptotic elements (p53 and cleaved caspase-3). In addition, the glutamate-induced alterations of neuronal activity indicators (brain-derived neurotrophic factor; BDNF and cAMP response element-binding protein phosphorylation; CREB) were significantly attenuated by CSE treatment. We also found that luteolin is the main bioactive compound corresponding to the anti-neuroexcitotoxic effects of CSE. Our results strongly suggest that Capsicum annuum L. seeds (but not its pulp) could be candidates for neuro-protective resources especially under conditions of neuroexcitotoxicity. Its underlying mechanisms may involve the amelioration of ROS-mediated cell death and BDNF-related neuronal inactivity and luteolin would be an active compound.

N-Acetyl cysteine amide and cerium oxide nanoparticles as a drug delivery for ischemic stroke treatment: Inflammation and oxidative stress crosstalk

BACKGROUND

Inflammation and oxidative stress crosstalk is involved in the ischemic stroke(IS) pathogenesis and the new therapeutic options should be offered based on the targets that are critical in the golden hour of IS. YKL-40 and total antioxidant capacity(TAC), the inflammation and oxidative stress biomarkers, provide us with clues for proper intervention targets. N-acetyl cysteine amide (NACA), a lipophilic antioxidant, with a nanoparticle-based drug delivery system is permeable enough to penetrate blood-brain barrier (BBB) and was proposed as a new treatment option for IS. In this study, we evaluated the YKL-40 and TAC levels in the sera of IS patients to elucidate the best intervention target. A rat tissue model is used to assess the NACA efficiency. The microbiology tests performed to figure out the potential NACA and antibiotics interactions.

MATERIAL AND METHODS

The YKL-40 and TAC were measured in the serum of IS patients by ELISA and FRAP methods, respectively. The serum samples were obtained 12 h after the patient's admission and meantime other laboratory findings and NIHSS-based prognosis were recorded. In the animal study, the brain cortex, liver, kidney, adipose, and the heart of healthy rats were dissected and then incubated in DMEM cell culture media containing 50 micrograms/milliliter of nanoparticles; the nanoparticles were titanium dioxide nanoparticles (TiO2 NPs), copper oxide nanoparticles (CuO NPs) and cerium dioxide nanoparticles (CeO2 NPs). Olive oil and human serum albumin solution were exposed to the nanoparticles with and without NACA. TAC was measured in the supernatant culture media. With similar concentrations and settings, we evaluated the NACA, nanoparticle, and antibiotics interactions on pseudomonas aeruginosa.

RESULTS

There was a nonparametric correlation between YKL-40 levels and post stroke serum TAC levels. Nonsmokers had higher YKL-40 and TAC levels than smokers. A new calculated variable, urea*lymphocyte/age, predicts a poor prognosis with an acceptable AUC (0.708). Exposing to the nanoparticles, the liver, kidney, and brain had a significantly higher TAC than adipose and cardiac tissue. The NACA had an ameliorative effect against TiO2 NPs in the brain. This effectiveness of NACA was also observed against CuO NPs treatment. However, the CeO2 NPs exert a strong antioxidant property by reducing the TAC in the brain tissue but not the others. Albumin showed antioxidant properties by itself, but olive oil had an inert behavior. NACA had no interaction with the action of routine antibiotics.

CONCLUSION

Oxidative stress but not inflammation is the best point for intervention in IS patients because YKL-40 has not a relationship with NIHSS score. The CeO2 NPs and NACA combination are eligible option to develop antioxidant-based drug for the treatment of IS. As a complementary finding, the urea*lymphocyte/age is proposed as a NIHSS-based prognosis biomarker.

N-acetyl cysteine mitigates lung damage and inflammation after chlorine exposure in vivo and ex vivo

The objective of this study was to explore the effects of antioxidant treatments, specifically N-acetylcysteine (NAC) and N-acetylcysteine amide (NACA), in a mouse model of chlorine (Cl2)-induced lung injury. Additionally, the study aimed to investigate the utility of pig precision-cut lung slices (PCLS) as an ex vivo alternative for studying the short-term effects of Cl2 exposure and evaluating antioxidant treatments. The toxicological responses were analyzed in Cl2-exposed mice (inflammation, airway hyperresponsiveness (AHR)) and PCLS (viability, cytotoxicity, inflammatory mediators). Airways contractions were assessed using a small ventilator for mice and electric-field stimulation (EFS) for PCLS. Antioxidant treatments were administered to evaluate their effects. In Cl2-exposed mice, NAC treatment did not alleviate AHR, but it did reduce the number of neutrophils in bronchoalveolar lavage fluid and inflammatory mediators in lung tissue. In PCLS, exposure to Cl2 resulted in concentration-dependent toxicity, impairing the lung tissue's ability to respond to EFS-stimulation. NAC treatment increased viability, mitigated the toxic responses caused by Cl2 exposure, and maintained contractility comparable to unexposed controls. Interestingly, NACA did not provide any additional treatment effect beyond NAC in both models. In conclusion, the establishment of a pig model for Cl2-induced lung damage supports further investigation of NAC as a potential treatment. However, the lack of protective effects on AHR after NAC treatment in mice suggests that NAC alone may not be sufficient as a complete treatment for Cl2 injuries. Optimization of existing medications with a polypharmacy approach may be more successful in addressing the complex sequelae of Cl2-induced lung injury.

Everolimus attenuates glutamate-induced PC12 cells death

BACKGROUND

Glutamate-induced neuronal cell death plays a key role in neurodegenerative diseases such as Alzheimer's and Parkinson's diseases. Some recent studies reported the potential immunomodulatory and neuroprotective properties of inhibitors of serine-threonine kinase, mTOR (mammalian target of rapamycin). However, no study was conducted about the neuroprotective potential of everolimus (EVR), a selective and potent mTOR inhibitor. Therefore, this study was planned to investigate whether EVR has protective effects against glutamate-induced toxicity in PC12 cells, which are used as model for neurons injury, and to elucidate the underlying mechanism.

METHODS

PC12 cells were concurrently treated with glutamate (8 mM) and EVR (0-40 nM) for 24 h. Then, the cells viability, apoptosis rate, and apoptosis-related proteins (caspase-3, bax and bcl-2) were measured using MTT, annexin V/PI and immunoblotting assays.

RESULTS

Analyzing the protective effect of different concentrations of EVR (0-40 nM) against glutamate-induced cytotoxicity revealed a significant increase in cell viability in co-treatment regimen (p < 0.01). Also, EVR (40 nM) significantly (p < 0.01) inhibited glutamate-induced apoptosis through depressing the elevation of bax/bcl-2 ratio and expression of cleaved caspase-3, concentration depend.

CONCLUSION

The results demonstrated, for the first time, that EVR could protect against glutamate-mediated PC12 cell death via inhibiting apoptosis.

Traditional uses, chemical compounds, pharmacological activities and clinical studies on the traditional Chinese prescription Yi-Gan San

ETHNOPHARMACOLOGICAL RELEVANCE

A widely used traditional prescription, Yi-Gan San (YGS) is a remedy for neurodegenerative disorders. The formulation consists of seven Chinese medicinal materials in specific proportions, namely Uncariae Ramulus cum Uncis (Uncaria rhynchophylla (Miq.) Miq. ex Havil.), Bupleuri Radix (Bupleurum chinense DC.), Angelicae Sinensis Radix (Angelica sinensis (Oliv.) Diels), Chuanxiong Rhizoma (Ligusticum wallichii Franch.), Poria (Poria cocos (Schw.) Wolf), Atractylodis Macrocephalae Rhizoma (Atractylodes macrocephala Koidz.) and Glycyrrhizae Radix et Rhizoma (Glycyrrhiza uralensis Fisch.). Using YGS has been shown to alleviate various behavioural and psychological symptoms of dementia (BPSD).

AIM OF THIS REVIEW

The goal of this review is to give up-to-date information about the traditional uses, chemistry, pharmacology and clinical efficacy of YGS based on the scientific literature and to learn the current focus and provide references in the next step.

MATERIALS AND METHODS

The database search room was accessed using the search terms "Yi-Gan San" and "Yokukansan" to obtain results from resources such as Web of Science, PubMed, Google Scholar and Sci Finder Scholar. We not only consulted the literature of fellow authors for this review but also explored classical medical books.

RESULTS

YGS has been used to cure neurosis, sleeplessness, night weeping and restlessness in infants. Its chemical components primarily consist of triterpenes, flavonoids, phenolics, lactones, alkaloids and other types of compounds. These active ingredients displayed diverse pharmacological activities to ameliorate BPSD by regulating serotonergic, glutamatergic, cholinergic, dopaminergic, adrenergic, and GABAergic neurotransmission. In addition, YGS showed neuroprotective, antistress, and anti-inflammatory effects. The majority of cases of neurodegenerative disorders are treated with YGS, including Alzheimer's disease and dementia with Lewy bodies.

CONCLUSIONS

Based on previous studies, YGS has been used as a traditional prescription in East Asia, such as Japan, Korea and China, and it has diverse chemical compounds and multiple pharmacological activities. Nevertheless, few experimental studies have focused on chemical and quantitative YGS studies, suggesting that further comprehensive research on its chemicals and quality assessments is critical for future evaluations of drug efficacy.

Emerging therapeutic opportunities of novel thiol-amides, NAC-amide (AD4/NACA) and thioredoxin mimetics (TXM-Peptides) for neurodegenerative-related disorders

Understanding neurodegenerative diseases have challenged scientists for decades. It has become apparent that a decrease in life span is often correlated with the development of neurodegenerative disorders. Oxidative stress and the subsequent inflammatory damages appear to contribute to the different molecular and biochemical mechanisms associated with neurodegeneration. In this review, I examine the protective properties of novel amino acid based compounds, comprising the AD series (AD1-AD7) in particular N-acetylcysteine amide, AD4, also called NACA, and the series of thioredoxin mimetic (TXM) peptides, TXM-CB3-TXM-CB16. Designed to cross the blood-brain-barrier (BBB) and permeate the cell membrane, these antioxidant/anti-inflammatory compounds may enable effective treatment of neurodegenerative related disorders. The review addresses the molecular mechanism of cellular protection exhibited by these new reagents, focusing on the reversal of oxidative stress, mitochondrial stress, inflammatory damages, and prevention of premature cell death. In addition, it will cover the outlook of the clinical prospects of AD4/NACA and the thioredoxin-mimetic peptides, which are currently in development.

Involvement of Oxidative and Endoplasmic Reticulum Stress in RDH12-Related Retinopathies

Retinol dehydrogenase 12 (RDH12) is expressed in photoreceptor inner segments and catalyses the reduction of all-trans retinal (atRAL) to all-trans retinol (atROL), as part of the visual cycle. Mutations in RDH12 are primarily associated with autosomal recessive Leber congenital amaurosis. To further our understanding of the disease mechanisms, HEK-293 cell lines expressing wildtype (WT) and mutant RDH12 were created. The WT cells afforded protection from atRAL-induced toxicity and oxidative stress. Mutant RDH12 cells displayed reduced protein expression and activity, with an inability to protect cells from atRAL toxicity, inducing oxidative and endoplasmic reticulum (ER) stress, with upregulation of sXBP1, CHOP, and ATF4. Pregabalin, a retinal scavenger, attenuated atRAL-induced ER stress in the mutant RDH12 cell lines. A zebrafish rdh12 mutant model (rdh12^u533 c.17_23del; p.(Val6AlafsTer5)) was generated through CRISPR-Cas9 gene editing. Mutant fish showed disrupted phagocytosis through transmission electron microscopy, with increased phagosome size at 12 months post-fertilisation. Rhodopsin mislocalisation and reduced expression of atg12 and sod2 indicated early signs of a rod-predominant degeneration. A lack of functional RDH12 results in ER and oxidative stress representing key pathways to be targeted for potential therapeutics.

Continuous Monitoring Reveals Protective Effects of N-Acetylcysteine Amide on an Isogenic Microphysiological Model of the Neurovascular Unit

Microphysiological systems mimic the in vivo cellular ensemble and microenvironment with the goal of providing more human-like models for biopharmaceutical research. In this study, the first such model of the blood-brain barrier (BBB-on-chip) featuring both isogenic human induced pluripotent stem cell (hiPSC)-derived cells and continuous barrier integrity monitoring with <2 min temporal resolution is reported. Its capabilities are showcased in the first microphysiological study of nitrosative stress and antioxidant prophylaxis. Relying on off-stoichiometry thiol-ene-epoxy (OSTE+) for fabrication greatly facilitates assembly and sensor integration compared to the prevalent polydimethylsiloxane devices. The integrated cell-substrate endothelial resistance monitoring allows for capturing the formation and breakdown of the BBB model, which consists of cocultured hiPSC-derived endothelial-like and astrocyte-like cells. Clear cellular disruption is observed when exposing the BBB-on-chip to the nitrosative stressor linsidomine, and the barrier permeability and barrier-protective effects of the antioxidant N-acetylcysteine amide are reported. Using metabolomic network analysis reveals further drug-induced changes consistent with prior literature regarding, e.g., cysteine and glutathione involvement. A model like this opens new possibilities for drug screening studies and personalized medicine, relying solely on isogenic human-derived cells and providing high-resolution temporal readouts that can help in pharmacodynamic studies.

17-β Estradiol Rescued Immature Rat Brain against Glutamate-Induced Oxidative Stress and Neurodegeneration via Regulating Nrf2/HO-1 and MAP-Kinase Signaling Pathway

Dysregulated glutamate signaling, leading to neuronal excitotoxicity and death, has been associated with neurodegenerative pathologies. 17β-estradiol (E2) is a human steroid hormone having a role in reproduction, sexual maturation, brain health and biological activities. The study aimed to explain the neuroprotective role of E2 against glutamate-induced ROS production, MAP kinase-dependent neuroinflammation, synaptic dysfunction and neurodegeneration in the cortex and hippocampus of postnatal day 7 rat brain. Biochemical and immunofluorescence analyses were applied. Our results showed that a single subcutaneous injection of glutamate (10 mg/kg) induced brain oxidative stress after 4 h by disturbing the homeostasis of glutathione (GSH) and revealed an upsurge in ROS and LPO levels and downregulated the expression of Nrf2 and HO-1 antioxidant protein. The glutamate-exposed P7 pups illustrated increased phosphorylation of stress-activated c-Jun N-terminal kinase (JNK) and p38 kinase (p38) and downregulated expression of P-Erk1/2. This was accompanied by pathological neuroinflammation as revealed by enhanced gliosis with upregulated expression of GFAP and Iba-1, and the activation of proinflammatory cytokines (TNF-α) in glutamate-injected P7 pups. Moreover, exogenous glutamate also reduced the expression of synaptic markers (PSD-95, SYP) and induced apoptotic neurodegeneration in the cortical and hippocampal regions by dysregulating the expression of Bax, Bcl-2 and caspase-3 in the developing rat brain. On the contrary, co-treatment of E2 (10 mg/kg) with glutamate significantly abrogated brain neuroinflammation, neurodegeneration and synapse loss by alleviating brain oxidative stress by upregulating the Nrf2/HO-1 antioxidant pathway and by deactivating pro-apoptotic P-JNK/P-p38 and activation of pro-survival P-Erk1/2 MAP kinase pathways. In brief, the data demonstrate the neuroprotective role of E2 against glutamate excitotoxicity-induced neurodegeneration. The study also encourages future studies investigating if E2 may be a potent neuroprotective and neurotherapeutic agent in different neurodegenerative diseases.

Effects of N-Acetylcysteine and N-Acetylcysteine Amide on Erythrocyte Deformability and Oxidative Stress in a Rat Model of Lower Extremity Ischemia-Reperfusion Injury

N-acetylcysteine (NAC) is an antioxidant which works as a free radical scavenger and antiapoptotic agent. N-acetylcysteine-amide (NACA) is a modified form of NAC containing an amide group instead of a carboxyl group of NAC. Our study aims to investigate the effectiveness of these two substances on erythrocyte deformability and oxidative stress in muscle tissue. Materials and Methods. A total of 24 Wistar albino rats were used in our study. The animals were randomly divided into five groups as control (n: 6), ischemia (n: 6), NAC (n: 6), and NACA (n: 6). In the ischemia, NAC, and NACA groups, 120 min of ischemia and 120 min of reperfusion were achieved by placing nontraumatic vascular clamps across the abdominal aorta. The NAC and NACA groups were administered an injection 30 min before ischemia (100 mg/kg NAC; 100 mg/kg NACA; intravenous). Blood samples were taken from the animals at the end of the ischemic period. The lower extremity gastrocnemius muscle was isolated and stored at -80 degrees to assess the total antioxidant status (TAS), total oxidant status (TOS), and oxidative stress index (OSI) values and was analyzed. Results. The erythrocyte deformability index was found to be statistically significantly lower in rats treated with NAC and NACA before ischemia-reperfusion compared to the groups that received only ischemia-reperfusion. In addition, no statistically significant difference was found between the control group and the NAC and NACA groups. The groups receiving NAC and NACA before ischemia exhibited higher total antioxidative status and lower total oxidative status while the oxidative stress index was also lower. Conclusion. The results of our study demonstrated the protective effects of NAC and NACA on erythrocyte deformability and oxidative damage in skeletal muscle in lower extremity ischemia-reperfusion. NAC and NACA exhibited similar protective effects on oxidative damage and erythrocyte deformability.

Prevention of the harmful effects of free oxygen radicals by using N-acetylcysteine in testicular torsion

INTRODUCTION

Testicular torsion is a urological emergency both in childhood and in adult life. Many studies on experimental testicular torsion have demonstrated biochemical and pathological ischemia-reperfusion injury and the efficacy of some drugs have been investigated to prevent this damage. N-acetylcysteine (NAC) promotes glutathione synthesis and acts as a glutathione precursor because of the fact that it increases the glutathione-reductase activity by transporting sulfhydryl groups.

AIM

In this experimental study, the authors aimed to investigate the effectiveness of NAC in preventing ischemia-reperfusion injury following testicular torsion and detorsion.

STUDY DESIGN

For this experimental study, 36 albino Wistar-male rats were used. The rats were randomly divided into 4 groups: sham (n = 8), ischemia-reperfusion (n = 8), ischemia-NAC -reperfusion (n = 10), and ischemia-NAC-reperfusion-NAC (n = 10) groups. Two hours of torsion and 4 h of detorsion were created in the left testis. After 4 h of detorsion, the rats were sacrificed. Each tissue was divided into two sections for biochemical and pathological examinations.

RESULTS

There was a statistically significant difference between the study groups in terms of the total-sulfhydryl level, nitric oxide level, and the malondialdehyde values. Histopathological examination revealed that NAC was effective in preventing reperfusion injury in the testis but ineffective in preventing the reduction in the spermatid count.

DISCUSSION

The results of this experimental study support that NAC can histopathologically maintain the structure of seminiferous tubules against ischemis reperfusion injury and prevent damage to the germinative cells. However, it was unable to prevent the reduction in spermatid count. There was no significant difference in the prevention of ischemia-reperfusion injury between NAC administration during the first hour of ischemia and NAC administration during reperfusion. Although NAC can prevent tissue damage from ischemia reperfusion injury, it is not effective against the reduction in the spermatid count.

CONCLUSION

N-acetylcysteine may be biochemically effective in preventing ischemia-reperfusion injury after testicular torsion and detorsion. NAC is a readily available and easy to use agent that can be used during testicular ischemia.

N-acetylcysteine reduces glutamate-induced cytotoxicity to fibroblasts of rat supraspinatus tendons

Purpose: Neuronal theory regarding rotator cuff degeneration has developed from the findings that glutamate, an amino acid and an excitatory neurotransmitter, is present in increased concentrations in tendon tissues with tendinopathy and that glutamate induces cell death in fibroblasts of origin in rat supraspinatus tendon. The purpose of the current study was to determine whether N-acetylcysteine (NAC) has cytoprotective effects against glutamate-induced fibroblast death. Materials and Methods: Primary cultured fibroblasts were obtained from rat supraspinatus tendons. Varying concentrations of glutamate (0.5, 1, 5, and 10 mM) and of NAC (0.5, 1, 2, and 5 mM) were used for evaluation of cytotoxicity. Cell viability, cell cycles, types of cell death, intracellular ROS production, expressions of caspase-3/7, and Ca²⁺ influx were evaluated. Results: Glutamate significantly induced cell death, apoptosis, and Ca²⁺ influx and significantly increased caspase-3/7 activity and intracellular ROS production (p < 0.001). NAC significantly reduced the glutamate-induced cell death, apoptosis, Ca²⁺ influx, caspase-3/7 activity, and intracellular ROS production (p < 0.001). Conclusions: The glutamate-induced cytotoxic effects can be reduced by NAC, an antioxidant, through the reduction of intracellular oxidative stress and/or Ca²⁺ influx.

Comparison of the Effects of Yokukansan and Yokukansankachimpihange on Glutamate Uptake by Cultured Astrocytes and Glutamate-Induced Excitotoxicity in Cultured PC12 Cells

The traditional Japanese Kampo medicine yokukansan (YKS) is effective for behavioral and psychological symptoms of dementia (BPSD) in patients with Alzheimer's disease. As the pharmacological mechanisms, YKS is known to protect astrocytes from thiamine-deficiency (TD)-induced decreased glutamate (Glu) uptake and neuron model cells (PC 12 cells) from Glu-induced death. Yokukansankachimpihange (YKSCH) is an alternative formula to YKS, in which Citrus unshiu peel and Pinellia tuber are added to the YKS components, and is sometimes used to treat BPSD, but its pharmacological properties remain unknown. This study aims to investigate the cellular pharmacological effects of YKS and YKSCH on glutamatergic pathways, compare their efficacy, and determine the differences and similarities in the activities between these formulations. First, we examined the effects of YKS and YKSCH on Glu uptake by cultured astrocytes under TD conditions. We observed significant ameliorative effects of YKS and YKSCH on the TD-induced decrease in Glu uptake, with a 50% effective dose of 8.9 ± 1.8 μg/mL and 45.3 ± 9.2 μg/mL, respectively. Second, using cultured PC12 cells as a model for neurons, we examined the effects of YKS and YKSCH on Glu-induced cell death. We observed that YKS and YKSCH had significant inhibitory effects on Glu-induced cell death, with a 30% effective dose of 51.4 ± 20.8 μg/mL and 49.2 ± 11.0 μg/mL, respectively. Thus, while YKSCH was less effective than YKS in ameliorating the TD-induced decrease in Glu uptake by astrocytes, the two drugs showed similar inhibitory effects on Glu-induced PC12 cell death. These findings are important for understanding the differences and similarities in pharmacological actions between these drugs.

N-acetylcysteine amide provides neuroprotection via Nrf2-ARE pathway in a mouse model of traumatic brain injury

Background

Increasing evidence demonstrate N-acetylcysteine amide (NACA) provides neuroprotection and attenuated oxidative stress in rats following traumatic brain injury (TBI). The nuclear factor erythroid 2-related factor 2 (Nrf2)–antioxidant response element (ARE) signal pathway is activated after TBI and provides a protective effect against TBI. However, the function and mechanism of NACA in mice after TBI remain unknown. This study was to evaluate the neuroprotection of NACA and the potential action of the Nrf2-ARE pathway in a weight-drop mouse model of TBI.

Materials and methods

Four groups of animals were randomly divided into sham, TBI, TBI+vehicle, and TBI+NACA (100 mg/kg, administered intraperitoneally). The protein levels of Nrf2, heme oxygenase-1 (HO-1), NAD(P)H: quinine oxidoreductase-1 (NQO1), cleaved caspase-3 and the mRNA levels of HO-1 and NQO1 were detected. The neurobehavior, neuronal degeneration, apoptosis and oxidative stress were also assessed.

Results

Treatment with NACA significantly improved neurologic status at days 1 and 3 following TBI. Moreover, NACA promoted Nrf2 activation a day after TBI. The protein and mRNA levels of HO-1 and NQO1 were upregulated by NACA. Meanwhile, NACA treatment significantly reduced the level of malondialdehyde (MDA) and enhanced the activity of superoxide dismutase (SOD) and glutathione peroxidase (GPx), which indicated NACA attenuated oxidative stress following TBI. NACA prominently reduced the protein level of cleaved caspase-3 and TUNEL-positive cells, indicating its antiapoptotic effect. Additionally, Fluoro-Jade C staining showed NACA alleviated neuronal degeneration a day after TBI.

Conclusions

Our study reveals that NACA potentially provides neuroprotection via the activation of the Nrf2-ARE signaling pathway after TBI in mice.

The Sources of Reactive Oxygen Species and Its Possible Role in the Pathogenesis of Parkinson's Disease

Parkinson's disease (PD) is the second most common neurodegenerative disorder characterized by progressive loss of dopaminergic neurons in the substantia nigra. The precise mechanism underlying pathogenesis of PD is not fully understood, but it has been widely accepted that excessive reactive oxygen species (ROS) are the key mediator of PD pathogenesis. The causative factors of PD such as gene mutation, neuroinflammation, and iron accumulation all could induce ROS generation, and the later would mediate the dopaminergic neuron death by causing oxidation protein, lipids, and other macromolecules in the cells. Obviously, it is of mechanistic and therapeutic significance to understand where ROS are derived and how ROS induce dopaminergic neuron damage. In the present review, we try to summarize and discuss the main source of ROS in PD and the key pathways through which ROS mediate DA neuron death.

Triphenylphosphonium Moiety Modulates Proteolytic Stability and Potentiates Neuroprotective Activity of Antioxidant Tetrapeptides in Vitro

Although delocalized lipophilic cations have been identified as effective cellular and mitochondrial carriers for a range of natural and synthetic drug molecules, little is known about their effects on pharmacological properties of peptides. The effect of triphenylphosphonium (TPP) cation on bioactivity of antioxidant tetrapeptides based on the model opioid YRFK motif was studied. Two tetrapeptide variants with L-arginine (YRFK) and D-arginine (YrFK) were synthesized and coupled with carboxyethyl-TPP (TPP-3) and carboxypentyl-TPP (TPP-6) units. The TPP moiety noticeably promoted YRFK cleavage by trypsin, but effectively prevented digestion of more resistant YrFK attributed, respectively, to structure-organizing and shielding effects of the TPP cation on conformational variants of the tetrapeptide motif. The TPP moiety enhanced radical scavenging activity of the modified YRFK in a model Fenton-like reaction, whereas decreased reactivity was revealed for both YrFK and its TPP derivative. The starting motifs and modified oligopeptides, especially the TPP-6 derivatives, suppressed acute oxidative stress in neuronal PC-12 cells during a brief exposure similarly with glutathione. The effect of oligopeptides was compared upon culturing of PC-12 cells with CoCl2, L-glutamic acid, or menadione to mimic physiologically relevant oxidative states. The cytoprotective activity of oligopeptides significantly depended on the type of oxidative factor, order of treatment and peptide structure. Pronounced cell-protective effect was established for the TPP-modified oligopeptides, which surpassed that of the unmodified motifs. The protease-resistant TPP-modified YrFK showed the highest activity when administered 24 h prior to the cell damage. Our results suggest that the TPP cation can be used as a modifier for small therapeutic peptides to improve their pharmacokinetic and pharmacological properties.

Neuroprotective Effects of Acetylcholinesterase Inhibitory Peptides from Anchovy (Coilia mystus) against Glutamate-Induced Toxicity in PC12 Cells

Ameliorations of cholinergic system dysfunction and oxidative stress in neurodegenerative diseases were main approaches to improve memory disorder. Our previous investigation showed that anchovy protein hydrolysate (APH) could attenuate scopolamine-induced memory deficits in mice by regulating acetylcholinesterase (AChE) activity. Therefore, peptides with AChE inhibitory activity in APH were explored and identified in this study, and their possible neuroprotective mechanisms on glutamate induced apoptosis in PC12 were also elucidated. Two peptides with strong AChE inhibitory capacity were identified as Pro-Ala-Tyr-Cys-Ser (PAYCS) and Cys-Val-Gly-Ser-Tyr (CVGSY) by ultraperformance liquid chromatography coupled with tandem mass spectrometry. The AChE inhibitory was 23.68 ± 0.97% and 6.08 ± 0.41%, respectively. Treatment with PAYCS and CVGSY could significantly (p < 0.05) increase cells viability, reduce lactate dehydrogenase release, reactive oxygen species (ROS) production, malondialdehyde content, and the ratio of Bax/Bcl-2 of glutamate-induced apoptosis PC12 cells (82.78 ± 6.58 and 109.94 ± 7.16% of control, respectively) as well as increase superoxide dismutase and GSH-px activities. In addition, both the peptides could inhibit Ca²⁺ influx but have no effects on mitochondrial membrane potential. Results indicated that AChE inhibitory peptides (PAYCS and CVGSY) possibly protected the PC12 cells against glutamate-induced apoptosis via inhibiting ROS production and Ca²⁺ influx. PAYCS and CVGSY might be considered as nutraceuticals for alleviating memory deficits.

Identification of novel N-acetylcysteine derivatives for the treatment of hepatocellular injury

New anti-hepatocellular injury drugs with better curative effects and fewer side effects are urgently needed at present. In this study, a series of novel N-acetylcysteine (NAC) derivatives were designed, synthesized and biologically evaluated for their anti-hepatocellular injury activities against two different cell models. In the biological evaluation against hydrogen peroxide (H2O2)-induced LO2 hepatocytes, half of the target compounds exhibited moderate to potent activities in improving the model cell viability, and two compounds (6a and 6b) displayed more potent activities in decreasing malondialdehyde (MDA) levels than the positive control NAC. In further 4-acetamidophenol (APAP)-induced LO2 cell experiment, compounds 6a and 6b could not only improve the cell viability but also significantly reduce the secretion of MDA. Additionally, compound 6a displayed excellent Caco-2 permeability and oral bioavailability in rats. All these experimental results suggested that compounds 6a and 6b could serve as potential lead molecules for further development of anti-hepatocellular injury drugs.

N-acetyl-cysteine prevents age-related hearing loss and the progressive loss of inner hair cells in γ-glutamyl transferase 1 deficient mice

Genetic factors combined with oxidative stress are major determinants of age-related hearing loss (ARHL), one of the most prevalent disorders of the elderly. Dwarf grey mice, Ggt1^dwg/dwg, are homozygous for a loss of function mutation of the γ-glutamyl transferase 1 gene, which encodes an important antioxidant enzyme critical for the resynthesis of glutathione (GSH). Since GSH reduces oxidative damage, we hypothesized that Ggt1^dwg/dwg mice would be susceptible to ARHL. Surprisingly, otoacoustic emissions and cochlear microphonic potentials, which reflect cochlear outer hair cell (OHC) function, were largely unaffected in mutant mice, whereas auditory brainstem responses and the compound action potential were grossly abnormal. These functional deficits were associated with an unusual and selective loss of inner hair cells (IHC), but retention of OHC and auditory nerve fibers. Remarkably, hearing deficits and IHC loss were completely prevented by N-acetyl-L-cysteine, which induces de novo synthesis of GSH; however, hearing deficits and IHC loss reappeared when treatment was discontinued. Ggt1^dwg/dwgmice represent an important new model for investigating ARHL, therapeutic interventions, and understanding the perceptual and electrophysiological consequences of sensory deprivation caused by the loss of sensory input exclusively from IHC.

Cellular Pharmacological Effects of the Traditional Japanese Kampo Medicine Yokukansan on Brain Cells

Yokukansan (YKS) is a traditional Japanese Kampo medicine currently used for the treatment of the behavioral psychological symptoms associated with dementia (BPSD), which is frequently problematic in neurodegenerative disorders such as Alzheimer’s disease. Regarding the pharmacological mechanisms underlying its efficacy, we recently reviewed the multiple effects of YKS on the neurotransmitter systems (e.g., glutamatergic, serotonergic, dopaminergic, cholinergic, GABAergic, and adrenergic neurotransmission) in various brain regions that are related to the psychological, emotional, cognitive, or memory functions. These multiple effects are thought to be caused by multiple components included in YKS. In addition, YKS exhibits various effects on brain cells (i.e., neurons, glial cells including astrocytes, oligodendrocytes, and microglial cells, and endothelial cells). In this review, we summarize recent evidence demonstrating the cellular pharmacological effects of YKS on these brain cells, and discuss the current understanding of its efficacy and mechanism. In particular, YKS maintains the neuronal survival and function by multiple beneficial effects, including anti-apoptosis, anti-oxidation, anti-endoplasmic reticulum stress, and neurogenesis. YKS also acts on glial cells by: facilitating the transport of glutamate into astrocytes; promoting the proliferation and differentiation of oligodendrocytes; and enhancing the anti-inflammatory properties of microglial cells. These glial effects are thought to support neuronal functioning within the brain. Various ingredients involved in these effects have been identified, some of which can pass through the artificial blood–brain barrier without disrupting the endothelial tight junctions. This multitude of interactive effects displayed by YKS on neuronal and glial cells is suggested to be involved in the multitude of neuropsychopharmacological actions of YKS, which are related to the improvement of BPSD.

Prevention and reversal of selenite-induced cataracts by N-acetylcysteine amide in Wistar rats

BACKGROUND

The present study sought to evaluate the efficacy of N-acetylcysteine amide (NACA) eye drops in reversing the cataract formation induced by sodium selenite in male Wistar rat pups.

METHODS

Forty male Wistar rat pups were randomly divided into a control group, an N-acetylcysteine amide-only group, a sodium selenite-induced cataract group, and a NACA-treated sodium selenite-induced cataract group. Sodium selenite was injected intraperitoneally on postpartum day 10, whereas N-acetylcysteine amide was injected intraperitoneally on postpartum days 9, 11, and 13 in the respective groups. Cataracts were evaluated at the end of week 2 (postpartum day 14) when the rat pups opened their eyes. N-acetylcysteine amide eye drops were administered beginning on week 3 until the end of week 4 (postpartum days 15 to 30), and the rats were sacrificed at the end of week 4. Lenses were isolated and examined for oxidative stress parameters such as glutathione, lipid peroxidation, and calcium levels along with the glutathione reductase and thioltransferase enzyme activities. Casein zymography and Western blot of m-calpain were performed using the water soluble fraction of lens proteins.

RESULTS

Morphological examination of the lenses in the NACA-treated group indicated that NACA was able to reverse the cataract grade. In addition, glutathione level, thioltransferase activity, m-calpain activity, and m-calpain level (as assessed by Western blot) were all significantly higher in the NACA-treated group than in the sodium selenite-induced cataract group. Furthermore, sodium selenite- injected rat pups had significantly higher levels of malondialdehyde, glutathione reductase enzyme activity, and calcium levels, which were reduced to control levels upon treatment with NACA.

CONCLUSIONS

The data suggest that NACA has the potential to significantly improve vision and decrease the burden of cataract-related loss of function. Prevention and reversal of cataract formation could have a global impact. Development of pharmacological agents like NACA may eventually prevent cataract formation in high-risk populations and may prevent progression of early-stage cataracts. This brings a paradigm shift from expensive surgical treatment of cataracts to relatively inexpensive prevention of vision loss.

Novel sila-amide derivatives of N-acetylcysteine protects platelets from oxidative stress-induced apoptosis

Oxidative stress-induced platelet apoptosis is one among the many causes for the development and progression of many disorders like cardiovascular diseases, arthritis, Alzheimer's disease and many chronic inflammatory responses. Many studies have demonstrated the less optimal effect of N-acetyl cysteine (NAC) in oxidative stress-induced cellular damage. This could be due to its less lipophilicity which makes it difficult to enter the cellular membrane. Therefore in the present study, lipophilic sila-amide derivatives (6a and 6b) synthesized through the reaction of NAC with 3-Aminopropyltrimethylsilane and aminomethyltrimethylsilane were used to determine their protective property against oxidative stress-induced platelet apoptosis. At a concentration of 10 µM, compound 6a and 6b were able to significantly inhibit Rotenone/H₂O₂ induced platelet apoptotic markers like reactive oxygen species, intracellular calcium level, mitochondrial membrane potential, cytochrome c release from mitochondrial to the cytosol, caspase-9 and -3 activity and phosphatidylserine externalization. Therefore, the compounds can be extrapolated as therapeutic agents to protect platelets from oxidative stress-induced platelet apoptosis and its associated complications.

N-acetylcysteine amide (AD4) reduces cocaine-induced reinstatement

RATIONALE

Chronic exposure to drugs of abuse changes glutamatergic transmission in human addicts and animal models. N-acetylcysteine (NAC) is a cysteine prodrug that indirectly activates cysteine-glutamate antiporters. In the extrasynaptic space, NAC restores basal glutamate levels during drug abstinence and normalizes increased glutamatergic tone in rats during reinstatement to drugs of abuse. In initial clinical trials, repeated NAC administration seems to be promising for reduced craving in cocaine addicts.

OBJECTIVE

In this study, NAC-amide, called AD4 or NACA, was examined in intravenous cocaine self-administration and extinction/reinstatement procedures in rats. We investigated the behavioral effects of AD4 in the olfactory bulbectomized (OBX) rats, considered an animal model of depression. Finally, we tested rats injected with AD4 or NAC during 10-daily extinction training sessions to examine subsequent cocaine seeking.

RESULTS

AD4 (25-75 mg kg(-1)) given acutely did not alter the rewarding effects of cocaine in OBX rats and sham-operated controls. However, at 6.25-50 mg kg(-1), AD4 decreased dose-dependently cocaine seeking and relapse triggered by cocaine priming or drug-associated conditioned cues in both phenotypes. Furthermore, repeated treatment with AD4 (25 mg kg(-1)) or NAC (100 mg kg(-1)) during daily extinction trials reduced reinstatement of drug-seeking behavior in sham-operated controls. In the OBX rats only, AD4 effectively blocked cocaine-seeking behavior.

CONCLUSIONS

Our results demonstrate that AD4 is effective at blocking cocaine-seeking behavior, highlighting its potential clinical use toward cocaine use disorder.

Boswellia serrata Protects Against Glutamate-Induced Oxidative Stress and Apoptosis in PC12 and N2a Cells

This study was designed to investigate whether the extract from Boswellia serrata oleo-gum resin (BSE) can protect against glutamate-induced oxidative damage and cytotoxicity in PC12 and N2a cell lines. Using a simple and reliable reverse-phase high-performance liquid chromatography (HPLC), the amount of 3-acetyl-11-keto-β-boswellic acid (AKBA) in the BSE was found to be 18.5% w/w. The results confirmed that BSE and AKBA, at concentrations as high as 100 μg/mL or 10 μM, respectively, caused no significant cytotoxicity or apoptotic cell death. Co- and pretreatment with BSE (25-100 μg/mL) or AKBA (5 μM) restored the viability of PC12 and N2a cells under glutamate toxicity (8 mM). Treatment with BSE and AKBA also attenuated the toxic effects of glutamate on intracellular reactive oxygen species, lipid peroxidation, superoxide dismutase activity, and oxidative DNA damage compared with the untreated glutamate-injured cells. Furthermore, BSE and AKBA decreased the apoptotic cell population in the sub-G1 region and the rate of both early and late-stage apoptosis induced by glutamate in the cells. Our data suggest that the protective effects of Boswellia extract and AKBA against glutamate toxicity in PC12 and N2a cells may be mediated through the amelioration of the oxidative stress and the resultant apoptosis.

Neuropharmacological efficacy of the traditional Japanese Kampo medicine yokukansan and its active ingredients

Dementia is a progressive neurodegenerative disorder with cognitive dysfunction, and is often complicated by behavioral and psychological symptoms of dementia (BPSD) including excitement, aggression, and hallucinations. Typical and atypical antipsychotics are used for the treatment of BPSD, but induce adverse events. The traditional Japanese Kampo medicine yokukansan (YKS), which had been originated from the traditional Chinese medicine Yi-Gan-San, has been reported to improve BPSD without severe adverse effects. In the preclinical basic studies, there are over 70 research articles indicating the neuropharmacological efficacies of YKS. In this review, we first describe the neuropharmacological actions of YKS and its bioactive ingredients. Multiple potential actions for YKS were identified, which include effects on serotonergic, glutamatergic, cholinergic, dopaminergic, adrenergic, and GABAergic neurotransmissions as well as neuroprotection, anti-stress effect, promotion of neuroplasticity, and anti-inflammatory effect. Geissoschizine methyl ether (GM) in Uncaria hook and 18β-glycyrrhetinic acid (GA) in Glycyrrhiza were responsible for several pharmacological actions of YKS. Subsequently, we describe the pharmacokinetics of GM and GA in rats. These ingredients were absorbed into the blood, crossed the blood-brain barrier, and reached the brain, in rats orally administered YKS. Moreover, autoradiography showed that [(3)H]GM predominantly distributed in the frontal cortex and [(3)H]GA in the hippocampus. Thus, YKS is a versatile herbal remedy with a variety of neuropharmacological effects, and may operate as a multicomponent drug including various active ingredients.

Neuroprotective effects of adenosine isolated from Cordyceps cicadae against oxidative and ER stress damages induced by glutamate in PC12 cells

Glutamate has been proven to induce oxidative stress through the formation of reactive oxygen species (ROS) and increased calcium overload which results in neuronal injury, development of neurodegenerative diseases and death. Adenosine is one of the bioactive nucleosides found in Cordyceps cicadae and it has displayed several pharmacological activities including neuroprotection. In this study, the protective effects of adenosine from C. cicadae against glutamate-induce oxidative stress in PC12 cells were evaluated. The exposure of PC12 cells to glutamate (5mM) induced the formation of ROS, increased Ca(2+) influx, endoplasmic reticulum (ER) stress and up regulated the expression of pro-apoptotic factor Bax. However, pretreatment with adenosine markedly increased cell viability, decreased the elevated levels of ROS and Ca(2+) induced by glutamate. Furthermore adenosine increased the activities of GSH-Px and SOD, as well as retained mitochondria membrane potential (MMP), increased Bcl-2/Bax ratio, and reduced the expression of ERK, p38, and JNK. Overall, our results suggest that adenosine may be a promising potential therapeutic agent for the prevention and treatment of neurodegenerative disorders.

Central GPR109A Activation Mediates Glutamate-Dependent Pressor Response in Conscious Rats

G protein-coupled receptor 109A (GPR109A) activation by its ligand nicotinic acid (NA) in immune cells increases Ca(2+) levels, and Ca(2+) induces glutamate release and oxidative stress in central blood pressure (BP)-regulating nuclei, for example, the rostral ventrolateral medulla (RVLM), leading to sympathoexcitation. Despite NA's ability to reach the brain, the expression and function of its receptor GPR109A in the RVLM remain unknown. We hypothesized that NA activation of RVLM GPR109A causes Ca(2+)-dependent l-glutamate release and subsequently increases neuronal oxidative stress, sympathetic activity, and BP. To test this hypothesis, we adopted a multilevel approach, which included pharmacologic in vivo studies along with ex vivo and in vitro molecular studies in rat pheochromocytoma cell line (PC12) cells (which exhibit neuronal phenotype). We present the first evidence for GPR109A expression in the RVLM and in PC12 cells. Next, we showed that RVLM GPR109A activation (NA) caused pressor and bradycardic responses in conscious rats. The resemblance of these responses to those caused by intra-RVLM glutamate and their attenuation by NMDA receptor (NMDAR) blockade (2-amino-5-phosphonopentanoic acid) and enhancement by l-glutamate uptake inhibition (l-trans-pyrrolidine-2,4-dicarboxylic acid, PDC) supported our hypothesis. NA increased Ca(2+), glutamate, nitric oxide and reactive oxygen species (ROS) levels in PC12 cells and increased RVLM ROS levels. The inactive NA analog isonicotinic acid failed to replicate the cardiovascular and biochemical effects of NA. Further, GPR109A knockdown (siRNA) abrogated the biochemical effects of NA in PC12 cells. These novel findings yield new insight into the role of RVLM GPR109A in central BP control.

Fatty acid binding protein-4 (FABP4) is a hypoxia inducible gene that sensitizes mice to liver ischemia/reperfusion injury

BACKGROUND & AIMS

Fatty acid binding protein 4 (FABP4) has been known as a mediator of inflammatory response in the macrophages and adipose tissue, but its hepatic function is poorly understood. The goal of this study is to investigate the role of FABP4 in liver ischemia/reperfusion (I/R), a clinical condition that involves both hypoxia and inflammation.

METHODS

To examine the I/R regulation of FABP4, mice were subjected to I/R surgery before being measured for FABP4 gene expression. Both loss-of-function (by using a pharmacological FABP4 inhibitor) and gain-of-function (by adenoviral overexpression of FABP4) were used to determine the functional relevance of FABP4 expression and its regulation during I/R. To determine the hypoxia responsive regulation of FABP4, primary mouse hepatocytes were exposed to hypoxia. The FABP4 gene promoter was cloned and its regulation by hypoxia inducible factor 1α (HIF-1α) was characterized by luciferase reporter gene, electrophoretic mobility shift, and chromatin immunoprecipitation assays.

RESULTS

We found that the hepatic expression of FABP4 was markedly induced by I/R. At the functional level, pharmacological inhibition of FABP4 alleviated the I/R injury, whereas adenoviral overexpression of FABP4 sensitized mice to I/R injury. We also showed that exposure of primary hepatocytes to hypoxia or transgenic overexpression of HIF-1α in the mouse liver was sufficient to induce the expression of FABP4. Our promoter analysis established FABP4 as a novel transcriptional target of HIF-1α.

CONCLUSIONS

FABP4 is a hypoxia inducible gene that sensitizes mice to liver I/R injury. FABP4 may represent a novel therapeutic target, and FABP4 inhibitors may be used as therapeutic agents to manage hepatic I/R injury.

Neuroprotective effects of N-acetylcysteine amide on experimental focal penetrating brain injury in rats

We examined the effects of N-acetylcysteine amide (NACA) in the secondary inflammatory response following a novel method of focal penetrating traumatic brain injury (TBI) in rats. N-acetylcysteine (NAC) has limited but well-documented neuroprotective effects after experimental central nervous system ischemia and TBI, but its bioavailability is very low. We tested NACA, a modified form of NAC with higher membrane and blood-brain barrier permeability. Focal penetrating TBI was produced in male Sprague-Dawley rats randomly selected for NACA treatment (n=5) and no treatment (n=5). In addition, four animals were submitted to sham surgery. After 2 hours or 24 hours the brains were removed, fresh frozen, cut in 14 μm coronal sections and subjected to immunohistochemistry, immunofluorescence, Fluoro-Jade and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) analyses. All treated animals were given 300 mg/kg NACA intraperitoneally (IP) 2 minutes post trauma. The 24 hour survival group was given an additional bolus of 300 mg/kg IP after 4 hours. NACA treatment decreased neuronal degeneration by Fluoro-Jade at 24 hours with a mean change of 35.0% (p<0.05) and decreased TUNEL staining indicative of apoptosis at 2 hours with a mean change of 38.7% (p<0.05). Manganese superoxide dismutase (MnSOD) increased in the NACA treatment group at 24 hours with a mean change of 35.9% (p<0.05). Levels of migrating macrophages and activated microglia (Ox-42/CD11b), nitric oxide-producing inflammatory enzyme iNOS, peroxynitrite marker 3-nitrotyrosine, NFκB translocated to the nuclei, cytochrome C and Bcl-2 were not affected. NACA treatment decreased neuronal degeneration and apoptosis and increased levels of antioxidative enzyme MnSOD. The antiapoptotic effect was likely regulated by pathways other than cytochrome C. Therefore, NACA prevents brain tissue damage after focal penetrating TBI, warranting further studies towards a clinical application.

Acetylated chitosan oligosaccharides act as antagonists against glutamate-induced PC12 cell death via Bcl-2/Bax signal pathway

Chitosan oligosaccharides (COSs), depolymerized products of chitosan composed of β-(1→4) d-glucosamine units, have broad range of biological activities such as antitumour, antifungal, and antioxidant activities. In this study, peracetylated chitosan oligosaccharides (PACOs) and N-acetylated chitosan oligosaccharides (NACOs) were prepared from the COSs by chemcal modification. The structures of these monomers were identified using NMR and ESI-MS spectra. Their antagonist effects against glutamate-induced PC12 cell death were investigated. The results showed that pretreatment of PC12 cells with the PACOs markedly inhibited glutamate-induced cell death in a concentration-dependent manner. The PACOs were better glutamate antagonists compared to the COSs and the NACOs, suggesting the peracetylation is essential for the neuroprotective effects of chitosan oligosaccharides. In addition, the PACOs pretreatment significantly reduced lactate dehydrogenase release and reactive oxygen species production. It also attenuated the loss of mitochondrial membrane potential. Further studies indicated that the PACOs inhibited glutamate-induced cell death by preventing apoptosis through depressing the elevation of Bax/Bcl-2 ratio and caspase-3 activation. These results suggest that PACOs might be promising antagonists against glutamate-induced neural cell death.

Yokukansan, a kampo medicine, protects PC12 cells from glutamate-induced death by augmenting gene expression of cystine/glutamate antiporter system Xc-

Effects of the kampo medicine yokukansan on gene expression of the cystine/glutamate antiporter system Xc-, which protects against glutamate-induced cytotoxicity, were examined in Pheochromocytoma cells (PC12 cells). Yokukansan inhibited glutamate-induced PC12 cell death. Similar cytoprotective effects were found in Uncaria hook. Experiments to clarify the active compounds revealed that geissoschizine methyl ether, hirsuteine, hirsutine, and procyanidin B1 in Uncaria hook, had cytoprotective effects. These components enhanced gene expressions of system Xc- subunits xCT and 4F2hc, and also ameliorated the glutamate-induced decrease in glutathione levels. These results suggest that the cytoprotective effect of yokukansan may be attributed to geissoschizine methyl ether, hirsuteine, hirsutine, and procyanidin B1 in Uncaria hook.

Essential hypertension and oxidative stress: New insights

Essential hypertension is a highly prevalent pathological condition that is considered as one of the most relevant cardiovascular risk factors and is an important cause of morbidity and mortality around the world. Despite the fact that mechanisms underlying hypertension are not yet fully elucidated, a large amount of evidence shows that oxidative stress plays a central role in its pathophysiology. Oxidative stress can be defined as an imbalance between oxidant agents, such as superoxide anion, and antioxidant molecules, and leads to a decrease in nitric oxide bioavailability, which is the main factor responsible for maintaining the vascular tone. Several vasoconstrictor peptides, such as angiotensin II, endothelin-1 and urotensin II, act through their receptors to stimulate the production of reactive oxygen species, by activating enzymes like NADPH oxidase and xanthine oxidase. The knowledge of the mechanism described above has allowed generating new therapeutic strategies against hypertension based on the use of antioxidants agents, including vitamin C and E, N-Acetylcysteine, polyphenols and selenium, among others. These substances have different therapeutic targets, but all represent antioxidant reinforcement. Several clinical trials using antioxidants have been made. The aim of the present review is to provide new insights about the key role of oxidative stress in the pathophysiology of essential hypertension and new clinical attempts to demonstrate the usefulness of antioxidant therapy in the treatment of hypertension.

N-acetylcysteine amide preserves mitochondrial bioenergetics and improves functional recovery following spinal trauma

Mitochondrial dysfunction is becoming a pivotal target for neuroprotective strategies following contusion spinal cord injury (SCI) and the pharmacological compounds that maintain mitochondrial function confer neuroprotection and improve long-term hindlimb function after injury. In the current study we evaluated the efficacy of cell-permeating thiol, N-acetylcysteine amide (NACA), a precursor of endogenous antioxidant glutathione (GSH), on mitochondrial function acutely, and long-term tissue sparing and hindlimb locomotor recovery following upper lumbar contusion SCI. Some designated injured adult female Sprague-Dawley rats (n=120) received either vehicle or NACA (75, 150, 300 or 600mg/kg) at 15min and 6h post-injury. After 24h the total, synaptic, and non-synaptic mitochondrial populations were isolated from a single 1.5cm spinal cord segment (centered at injury site) and assessed for mitochondrial bioenergetics. Results showed compromised total mitochondrial bioenergetics following acute SCI that was significantly improved with NACA treatment in a dose-dependent manner, with maximum effects at 300mg/kg (n=4/group). For synaptic and non-synaptic mitochondria, only 300mg/kg NACA dosage showed efficacy. Similar dosage (300mg/kg) also maintained mitochondrial GSH near normal levels. Other designated injured rats (n=21) received continuous NACA (150 or 300mg/kg/day) treatment starting at 15min post-injury for one week to assess long-term functional recovery over 6weeks post-injury. Locomotor testing and novel gait analyses showed significantly improved hindlimb function with NACA that were associated with increased tissue sparing at the injury site. Overall, NACA treatment significantly maintained acute mitochondrial bioenergetics and normalized GSH levels following SCI, and prolonged delivery resulted in significant tissue sparing and improved recovery of hindlimb function.

N-acetylcysteine amide preserves mitochondrial bioenergetics and improves functional recovery following spinal trauma

Mitochondrial dysfunction is becoming a pivotal target for neuroprotective strategies following contusion spinal cord injury (SCI) and the pharmacological compounds that maintain mitochondrial function confer neuroprotection and improve long-term hindlimb function after injury. In the current study we evaluated the efficacy of cell-permeating thiol, N-acetylcysteine amide (NACA), a precursor of endogenous antioxidant glutathione (GSH), on mitochondrial function acutely, and long-term tissue sparing and hindlimb locomotor recovery following upper lumbar contusion SCI. Some designated injured adult female Sprague-Dawley rats (n=120) received either vehicle or NACA (75, 150, 300 or 600mg/kg) at 15min and 6h post-injury. After 24h the total, synaptic, and non-synaptic mitochondrial populations were isolated from a single 1.5cm spinal cord segment (centered at injury site) and assessed for mitochondrial bioenergetics. Results showed compromised total mitochondrial bioenergetics following acute SCI that was significantly improved with NACA treatment in a dose-dependent manner, with maximum effects at 300mg/kg (n=4/group). For synaptic and non-synaptic mitochondria, only 300mg/kg NACA dosage showed efficacy. Similar dosage (300mg/kg) also maintained mitochondrial GSH near normal levels. Other designated injured rats (n=21) received continuous NACA (150 or 300mg/kg/day) treatment starting at 15min post-injury for one week to assess long-term functional recovery over 6weeks post-injury. Locomotor testing and novel gait analyses showed significantly improved hindlimb function with NACA that were associated with increased tissue sparing at the injury site. Overall, NACA treatment significantly maintained acute mitochondrial bioenergetics and normalized GSH levels following SCI, and prolonged delivery resulted in significant tissue sparing and improved recovery of hindlimb function.

N-acetylcysteine amide confers neuroprotection, improves bioenergetics and behavioral outcome following TBI

Traumatic brain injury (TBI) has become a growing epidemic but no approved pharmacological treatment has been identified. Our previous work indicates that mitochondrial oxidative stress/damage and loss of bioenergetics play a pivotal role in neuronal cell death and behavioral outcome following experimental TBI. One tactic that has had some experimental success is to target glutathione using its precursor N-acetylcysteine (NAC). However, this approach has been hindered by the low CNS bioavailability of NAC. The current study evaluated a novel, cell permeant amide form of N-acetylcysteine (NACA), which has high permeability through cellular and mitochondrial membranes resulting in increased CNS bioavailability. Cortical tissue sparing, cognitive function and oxidative stress markers were assessed in rats treated with NACA, NAC, or vehicle following a TBI. At 15days post-injury, animals treated with NACA demonstrated significant improvements in cognitive function and cortical tissue sparing compared to NAC or vehicle treated animals. NACA treatment also was shown to reduce oxidative damage (HNE levels) at 7days post-injury. Mechanistically, post-injury NACA administration was demonstrated to maintain levels of mitochondrial glutathione and mitochondrial bioenergetics comparable to sham animals. Collectively these data provide a basic platform to consider NACA as a novel therapeutic agent for treatment of TBI.