Aggregation of alpha-synuclein disrupts mitochondrial metabolism and induce mitophagy via cardiolipin externalization.

Accumulation of α-synuclein aggregates in the substantia nigra pars compacta is central in the pathophysiology of Parkinson's disease, leading to the degeneration of dopaminergic neurons and the manifestation of motor symptoms. Although several PD models mimic the pathological accumulation of α-synuclein after overexpression, they do not allow for controlling and monitoring its aggregation. We recently generated a new optogenetic tool by which we can spatiotemporally control the aggregation of α-synuclein using a light-induced protein aggregation system. Using this innovative tool, we aimed to characterize the impact of α-synuclein clustering on mitochondria, whose activity is crucial to maintain neuronal survival. We observed that aggregates of α-synuclein transiently and dynamically interact with mitochondria, leading to mitochondrial depolarization, lower ATP production, mitochondrial fragmentation and degradation via cardiolipin externalization-dependent mitophagy. Aggregation of α-synuclein also leads to lower mitochondrial content in human dopaminergic neurons and in mouse midbrain. Interestingly, overexpression of α-synuclein alone did not induce mitochondrial degradation. This work is among the first to clearly discriminate between the impact of α-synuclein overexpression and aggregation on mitochondria. This study thus represents a new framework to characterize the role of mitochondria in PD.

Connecting Dots between Mitochondrial Dysfunction and Depression.

Mitochondria are the prime source of cellular energy, and are also responsible for important processes such as oxidative stress, apoptosis and Ca2+ homeostasis. Depression is a psychiatric disease characterized by alteration in the metabolism, neurotransmission and neuroplasticity. In this manuscript, we summarize the recent evidence linking mitochondrial dysfunction to the pathophysiology of depression. Impaired expression of mitochondria-related genes, damage to mitochondrial membrane proteins and lipids, disruption of the electron transport chain, higher oxidative stress, neuroinflammation and apoptosis are all observed in preclinical models of depression and most of these parameters can be altered in the brain of patients with depression. A deeper knowledge of the depression pathophysiology and the identification of phenotypes and biomarkers with respect to mitochondrial dysfunction are needed to help early diagnosis and the development of new treatment strategies for this devastating disorder.

Molecular Understanding of ACE-2 and HLA-Conferred Differential Susceptibility to COVID-19: Host-Directed Insights Opening New Windows in COVID-19 Therapeutics.

The genetic variants of HLAs (human leukocyte antigens) play a crucial role in the virus-host interaction and pathology of COVID-19. The genetic variants of HLAs not only influence T cell immune responses but also B cell immune responses by presenting a variety of peptide fragments of invading pathogens. Peptide cocktail vaccines produced by using various conserved HLA-A2 epitopes provoke substantial specific CD8+ T cell responses in experimental animals. The HLA profiles vary among individuals and trigger different T cell-mediated immune responses in COVID-19 infections. Those with HLA-C*01 and HLA-B*44 are highly susceptible to the disease. However, HLA-A*02:01, HLA-DR*03:01, and HLA-Cw*15:02 alleles show resistance to SARS infection. Understanding the genetic association of HLA with COVID-19 susceptibility and severity is important because it can help in studying the transmission of COVID-19 and its physiopathogenesis. The HLA-C*01 and B*44 allele pathways can be studied to gain insight into disease transmission and physiopathogenesis. Therefore, integrating HLA testing is suggested in the ongoing pandemic, which will help in the rapid identification of highly susceptible populations worldwide and possibly acclimate vaccine development. Therefore, understanding the correlation between HLA and SARS-CoV-2 is critical in opening new insights into COVID-19 therapeutics, based on previous studies conducted.

Exploration of cytotoxic potential and tubulin polymerization inhibition activity of cis-stilbene-1,2,3-triazole congeners.

To scrutinize cis-stilbene based molecules with potential anticancer and tubulin polymerization inhibition activity, a new series of cis-stilbene-1,2,3-triazole congeners was designed and synthesized via a click chemistry protocol. The cytotoxicity of these compounds 9a-j and 10a-j was screened against lung, breast, skin and colorectal cancer cell lines. Based on the results of MTT assay, we further evaluated the selectivity index of the most active compound 9j (IC50 3.25 ± 1.04 µM on HCT-116) by comparing its IC50 value (72.24 ± 1.20 µM) to that of the normal human cell line. Further, to confirm apoptotic cell death, cell morphology and staining studies (AO/EB, DAPI and Annexin V/PI) were carried out. The outcomes of studies showed apoptotic features like change in cell shape, cornering of nuclei, micronuclei formation, fragmented, bright, horseshoe-shaped nuclei, etc. Moreover, active compound 9j displayed G2/M phase cell cycle arrest with significant tubulin polymerization inhibition activity with an IC50 value of 4.51 µM. Additionally, in silico ADMET, molecular docking and molecular dynamic studies of 9j with 3E22 protein proved the binding of the compound at the colchicine binding site of tubulin.

Mitochondrial matrix-localized Src kinase regulates mitochondrial morphology.

The architecture of mitochondria adapts to physiological contexts: while mitochondrial fragmentation is usually associated to quality control and cell death, mitochondrial elongation often enhances cell survival during stress. Understanding how these events are regulated is important to elucidate how mitochondrial dynamics control cell fate. Here, we show that the tyrosine kinase Src regulates mitochondrial morphology. Deletion of Src increased mitochondrial size and reduced cellular respiration independently of mitochondrial mass, mitochondrial membrane potential or ATP levels. Re-expression of Src targeted to the mitochondrial matrix, but not of Src targeted to the plasma membrane, rescued mitochondrial morphology in a kinase activity-dependent manner. These findings highlight a novel function for Src in the control of mitochondrial dynamics.

Preparation of Electrochemical Supercapacitor Based on Polypyrrole/Gum Arabic Composites.

The current research focused on the super capacitive behavior of organic conducting polymer, i.e., polypyrrole (PPy) and its composites with gum arabic (GA) prepared via inverse emulsion polymerization. The synthesized composites material was analyzed by different analytical techniques, such as UV-visible, FTIR, TGA, XRD, and SEM. The UV-Vis and FTIR spectroscopy clearly show the successful insertion of GA into PPy matrix. The TGA analysis shows high thermal stability for composites than pure PPy. The XRD and SEM analysis show the crystalline and amorphous structures and overall morphology of the composites is more compact and mesoporous as compared to the pure PPy. The electrochemical properties of modified solid state supercapacitors established on pure polypyrrole (PPy), polypyrrole/gum arabic (PPy/GA) based composites were investigated through cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge-discharge (GCD). The specific capacitance of the PPy modified gold electrode is impressive (~168 F/g). The specific capacitance of PPy/GA 1 electrode has been increased to 368 F/g with a high energy density and power density (~73 Wh/kg), and (~599 W/kg) respectively.

Synthesis, Characterization and Evaluation of Supercapacitive Response of Dodecylbenzenesulphonic Acid (DBSA) Doped Polypyrrole/Zirconium Dioxide Composites.

An in-situ chemical oxidative method was used to effectively synthesize a promising supercapacitor material based on PPy/ZrO2 composites. The synthesized materials were characterized by different analytical techniques, such as UV/visible (UV/Vis) spectroscopy, Fourier-transform infra-red spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The inclusion of ZrO2 into the PPy matrix was verified by vibrational spectra and structural analyses. The (TGA) results showed that incorporating ZrO2 into the polymeric matrix improved its thermal stability. In addition, the electrochemical properties of the synthesizedmaterials were investigated byusing cyclic voltammetry (CV) and galvanostatic charge/discharge (GCD). The PPy/ZrO2 composite demonstrated excellent super capacitive performance, and high specific capacity of 337.83 F/g, with an exceedingly high energy density of 187.68 Wh/kg at a power density of 1000 W/kg. The composite materials maintain good stability after 1000 charge and discharge cycles, with 85% capacitance retention. The PPy/ZrO2 possesses a high capacitance, an attractive micro-morphology, and a simple synthesis method. The findings indicate that the PPy/ZrO2 composite could be a promising electrode material for high-performance supercapacitor applications.

17ß-Estradiol Modulates SIRT1 and Halts Oxidative Stress-Mediated Cognitive Impairment in a Male Aging Mouse Model.

Oxidative stress has been considered the main mediator in neurodegenerative disease and in normal aging processes. Several studies have reported that the accumulation of reactive oxygen species (ROS), elevated oxidative stress, and neuroinflammation result in cellular malfunction. These conditions lead to neuronal cell death in aging-related neurodegenerative disorders such as Alzheimer's disease (AD) and Parkinson's disease. Chronic administration of d-galactose (d-gal) for a period of 10 weeks causes ROS generation and neuroinflammation, ultimately leading to cognitive impairment. In this study, we evaluated the estrogen receptor α (ERα)/silent mating type information regulation 2 homolog 1 (SIRT1)-dependent antioxidant efficacy of 17ß-estradiol against d-gal-induced oxidative damage-mediated cognitive dysfunction in a male mouse model. The results indicate that 17ß-estradiol, by stimulating ERα/SIRT1, halts d-gal-induced oxidative stress-mediated JNK/NF-Ò¡B overexpression, neuroinflammation and neuronal apoptosis. Moreover, 17ß-estradiol ameliorated d-gal-induced AD-like pathophysiology, synaptic dysfunction and memory impairment in adult mouse brains. Interestingly, inhibition of SIRT1 with Ex527 (a potent and selective SIRT1 inhibitor) further enhanced d-gal-induced toxicity and abolished the beneficial effect of 17ß-estradiol. Most importantly, for the first time, our molecular docking study reveals that 17ß-estradiol allosterically increases the expression of SIRT1 and abolishes the inhibitory potential of d-ga. In summary, we can conclude that 17ß-estradiol, in an ERα/SIRT1-dependent manner, abrogates d-gal-induced oxidative stress-mediated memory impairment, neuroinflammation, and neurodegeneration in adult mice.

MST1 Regulates Neuronal Cell Death via JNK/Casp3 Signaling Pathway in HFD Mouse Brain and HT22 Cells.

Oxidative stress has been considered as the main mediator in neurodegenerative diseases. A high-fat diet (HFD) and metabolic diseases result in oxidative stress generation, leading to various neurodegenerative diseases via molecular mechanisms that remain largely unknown. Protein kinases play an important role in the homeostasis between cell survival and cell apoptosis. The mammalian sterile 20-like kinase-1 (MST1) protein kinase plays an important role in cellular apoptosis in different organ systems, including the central nervous system. In this study, we evaluated the MST1/c-Jun N-terminal kinase (JNK) dependent oxidative damage mediated cognitive dysfunction in HFD-fed mice and stress-induced hippocampal HT22 (mice hippocampal) cells. Our Western blot and immunofluorescence results indicate that HFD and stress-induced hippocampal HT22 cells activate MST1/JNK/Caspase-3 (Casp-3) signaling, which regulates neuronal cell apoptosis and beta-amyloid-cleaving enzyme (BACE1) expression and leads to impaired cognition. Moreover, MST1 expression inhibition by shRNA significantly reduced JNK/Casp-3 signaling. Our in vivo and in vitro experiments mimicking metabolic stress, such as a high-fat diet, hyperglycemia, and an inflammatory response, determined that MST1 plays a key regulatory role in neuronal cell death and cognition, suggesting that MST1 could be a potential therapeutic target for numerous neurodegenerative diseases.

Natural Antioxidant Anthocyanins-A Hidden Therapeutic Candidate in Metabolic Disorders with Major Focus in Neurodegeneration.

All over the world, metabolic syndrome constitutes severe health problems. Multiple factors have been reported in the pathogenesis of metabolic syndrome. Metabolic disorders result in reactive oxygen species (ROS) induced oxidative stress, playing a vital role in the development and pathogenesis of major health issues, including neurological disorders Alzheimer's disease (AD) Parkinson's disease (PD). Considerable increasing evidence indicates the substantial contribution of ROS-induced oxidative stress in neurodegenerative diseases. An imbalanced metabolism results in a defective antioxidant defense system, free radicals causing inflammation, cellular apoptosis, and tissue damage. Due to the annual increase in financial and social burdens, in addition to the adverse effects associated with available synthetic agents, treatment diversion from synthetic to natural approaches has occurred. Antioxidants are now being considered as convincing therapeutic agents against various neurodegenerative disorders. Therefore, medicinal herbs and fruits currently receive substantially more attention as commercial sources of antioxidants. In this review, we argue that ROS-targeted therapeutic interventions with naturally occurring antioxidant flavonoid, anthocyanin, and anthocyanin-loaded nanoparticles might be the ultimate treatment against devastating illnesses. Furthermore, we elucidate the hidden potential of the neuroprotective role of anthocyanins and anthocyanin-loaded nanoparticles in AD and PD neuropathies, which lack sufficient attention compared with other polyphenols, despite their strong antioxidant potential. Moreover, we address the need for future research studies of native anthocyanins and nano-based-anthocyanins, which will be helpful in developing anthocyanin treatments as therapeutic mitochondrial antioxidant drug-like regimens to delay or prevent the progression of neurodegenerative diseases, such as AD and PD.

Adiponectin homolog novel osmotin protects obesity/diabetes-induced NAFLD by upregulating AdipoRs/PPARα signaling in ob/ob and db/db transgenic mouse models.

BACKGROUND: In metabolic disorders, adiponectin and adiponectin receptors (AdipoR1/R2) signaling has a key role in improving nonalcoholic fatty liver disease (NAFLD) in obesity-associated diabetes. OBJECTIVE: To the best of our knowledge, here, we reported for the first time the underlying mechanistic therapeutic efficacy of the novel osmotin, a homolog of mammalian adiponectin, against NAFLD in leptin-deficient ob/ob and db/db mice. METHODS: The ob/ob and db/db mice were treated with osmotin at a dose of 5 µg/g three times a week for two weeks. To co-relate the in vivo results we used the human liver carcinoma HepG2 cells, subjected to knockdown with small siRNAs of AdipoR1/R2 and PPARα genes and treated with osmotin and palmitic acid (P.A.). MTT assay, Western blotting, immunohistofluorescence assays, and plasma biochemical analyses were applied. RESULTS: Osmotin stimulated AdipoR1/R2 and its downstream APPL1/PPAR-α/AMPK/SIRT1 pathways in ob/ob and db/db mice, and HepG2 cells exposed to P.A. Mechanistically, we confirmed that knockdown of AdipoR1/R2 and PPARα by their respective siRNAs abolished the osmotin activity in HepG2 cells exposed to P.A. Overall, the in vivo and in vitro results suggested that osmotin protected against NAFLD through activation of AdipoR1/R2 and its downstream APPL1/PPAR-α/AMPK/SIRT1 pathways as shown by the reduced body weight, blood glucose level and glycated hemoglobin, improved glucose tolerance, attenuated insulin resistance and hepatic glucogenesis, regulated serum lipid parameters, and increased fatty acid oxidation and mitochondrial functions. CONCLUSION: Our findings strongly suggest that novel osmotin might be a potential novel therapeutic tool against obesity/diabetes-induced NAFLD and other metabolic disorders.

Dental pulp-derived stem cells can counterbalance peripheral nerve injury-induced oxidative stress and supraspinal neuro-inflammation in rat brain.

Previously, we reported the successful regeneration of injured peripheral nerves using human dental pulp stem cells (DPSCs) or differentiated neuronal cells from DPSCs (DF-DPSCs) in a rat model. Here, we attempted to evaluate oxidative stress and supraspinal neuro-inflammation in rat brain after sciatic nerve injury (SNI). We divided our experimental animals into three SNI groups based on time. The expression of a microglial (Iba1) marker and reactive oxygen species (ROS) was lower in DPSCs and higher in DF-DPSCs. In contrast, the expression of an astroglial (GFAP) marker was higher in DPSCs and lower in DF-DPSCs at 2 weeks. However, the expression of ROS, Iba1 and GFAP gradually decreased at 8 and 12 weeks in the SNI DPSCs and DF-DPSCs groups compared to the SNI control. Furthermore, anti-inflammatory cytokine (IL-4 and TGF-ß) expression was lower at 2 weeks, while it gradually increased at 8 and 12 weeks after surgery in the SNI DPSCs and DF-DPSCs groups. Similarly, SNI DPSCs had a high expression of pAMPK, SIRT1 and NFkB at the onset of SNI. However, 12 weeks after surgery, pAMPK and SIRT1 expression levels were higher and NFkB was down-regulated in both DPSCs and DF-DPSCs compared to the control group. Finally, we concluded that DPSCs responded early and more efficiently than DF-DPSCs to counterbalance peripheral nerve injury (PNI)-induced oxidative stress and supraspinal neuro-inflammation in rat brain.

17ß-Estradiol via SIRT1/Acetyl-p53/NF-kB Signaling Pathway Rescued Postnatal Rat Brain Against Acute Ethanol Intoxication.

Growing evidences reveal that 17ß-estradiol has a wide variety of neuroprotective potential. Recently, it has been shown that 17ß-estradiol can limit ethanol-induced neurotoxicity in neonatal rats. Whether it can stimulate SIRT1 signaling against ethanol intoxicity in developing brain remain elusive. Here, we report for the first time that 17ß-estradiol activated SIRT1 to deacetylate p53 proteins against acute ethanol-induced oxidative stress, neuroinflammation, and neurodegeneration. A single subcutaneous injection of ethanol-induced oxidative stress triggered phospho c-jun N terminal kinase (p-JNK) and phospho mammalian target of rapamycin (p-mTOR) accompanied by neuroinflammation and widespread neurodegeneration. In contrast, 17ß-estradiol cotreatment positively regulated SIRT1, inhibited p53 acetylation, reactive oxygen species (ROS) production, p-JNK, and p-mTOR activation and reduced neuroinflammation and neuronal cell death in the postnatal rat brain. Interestingly, SIRT1 inhibition with its inhibitor, i.e., EX527 further enhanced ethanol intoxication and also abolished the beneficial effects of 17ß-estradiol against ethanol in the young rat's brain. Indeed, 17ß-estradiol treatment increased the cell viability (HT22 cells), inhibited ROS production via the SIRT1/Acetyl-p53 pathway, and reduced the nuclear translocation of phospho-nuclear factor kappa B (p-NF-kB) in the BV2 microglia cells. Taken together, these results show that 17ß-estradiol can be used as a potential neuroprotective agent against acute ethanol intoxication.

Natural Dietary Supplementation of Anthocyanins via PI3K/Akt/Nrf2/HO-1 Pathways Mitigate Oxidative Stress, Neurodegeneration, and Memory Impairment in a Mouse Model of Alzheimer's Disease.

Well-established studies have shown an elevated level of reactive oxygen species (ROS) that induces oxidative stress in the Alzheimer's disease (AD) patient's brain and an animal model of AD. Herein, we investigated the underlying anti-oxidant neuroprotective mechanism of natural dietary supplementation of anthocyanins extracted from Korean black beans in the amyloid precursor protein/presenilin-1 (APP/PS1) mouse model of AD. Both in vivo (APP/PS1 mice) and in vitro (mouse hippocampal HT22 cells) results demonstrated that anthocyanins regulate the phosphorylated-phosphatidylinositol 3-kinase-Akt-glycogen synthase kinase 3 beta (p-PI3K/Akt/GSK3ß) pathways and consequently attenuate amyloid beta oligomer (AßO)-induced elevations in ROS level and oxidative stress via stimulating the master endogenous anti-oxidant system of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (Nrf2/HO-1) pathways and prevent apoptosis and neurodegeneration by suppressing the apoptotic and neurodegenerative markers such as activation of caspase-3 and PARP-1 expression as well as the TUNEL and Fluoro-Jade B-positive neuronal cells in the APP/PS1 mice. In vitro ApoTox-Glo™ Triplex assay results also showed that anthocyanins act as a potent anti-oxidant neuroprotective agent and reduce AßO-induced neurotoxicity in the HT22 cells via PI3K/Akt/Nrf2 signaling. Importantly, anthocyanins improve memory-related pre- and postsynaptic protein markers and memory functions in the APP/PS1 mice. In conclusion, our data suggested that consumption and supplementation of natural-derived anti-oxidant neuroprotective agent such as anthocyanins may be beneficial and suggest new dietary-supplement strategies for intervention in and prevention of progressive neurodegenerative diseases, such as AD.

Inhibition of c-Jun N-Terminal Kinase Protects Against Brain Damage and Improves Learning and Memory After Traumatic Brain Injury in Adult Mice.

Traumatic brain injury (TBI) is a global risk factor that leads to long-term cognitive impairments. To date, the disease remains without effective therapeutics because of the multifactorial nature of the disease. Here, we demonstrated that activation of the c-Jun N-terminal kinase (JNK) is involved in multiple pathological features of TBI. Therefore, we investigated the disease-modifying therapeutic potential of JNK-specific inhibitor (SP600125) in TBI mice. Treating 2 different models of TBI mice with SP600125 for 7 days dramatically inhibited activated JNK, resulting in marked reductions of amyloid precursor protein (APP) expression level and in amyloid beta production and hyperphosphorylated tau and regulation of the abnormal expression of secretases. Furthermore, SP600125 strongly inhibited inflammatory responses, blood-brain barrier breakdown, apoptotic neurodegeneration, and synaptic protein loss, regulated prosurvival processes and improved motor function and behavioral outcomes in TBI mice. More interestingly, we found that SP600125 treatment ameliorated amyloidogenic APP processing and promoted the nonamyloidogenic pathway in TBI mouse brains. Our findings strongly suggest that active JNK is critically involved in disease development after TBI and that inhibition of JNK with SP600125 is highly efficient for slowing disease progression by reducing multiple pathological features in TBI mouse brains and regulating cognitive dysfunction.

Anthocyanins encapsulated by PLGA@PEG nanoparticles potentially improved its free radical scavenging capabilities via p38/JNK pathway against Aß1-42-induced oxidative stress.

BACKGROUND: In order to increase the bioavailability of hydrophilic unstable drugs like anthocyanins, we employed a polymer-based nanoparticles approach due to its unique properties such as high stability, improved bioavailability and high water-soluble drug loading efficiency. Anthocyanins constitute a subfamily of flavonoids that possess anti-oxidative, anti-inflammatory and neuroprotective properties. However, anthocyanins are unstable because their phenolic hydroxyl groups are easily oxidized into quinones, causing a reduced biological activity. To overcome this drawback and improve the free radical scavenging capabilities of anthocyanins, in the current study we for the first time encapsulated the anthocyanins in biodegradable nanoparticle formulation based on poly (lactide-co-glycolide) (PLGA) and a stabilizer polyethylene glycol (PEG)-2000. The biological activity and neuroprotective effect of anthocyanin loaded nanoparticles (An-NPs) were investigated in SH-SY5Y cell lines. RESULTS: Morphological examination under transmission electron microscopy (TEM) showed the formation of smooth spherically shaped nanoparticles. The average particle size and zeta potential of An-NPs were in the range of 120-165 nm and -12 mV respectively, with a low polydispersity index (0.4) and displayed a biphasic release profile in vitro. Anthocyanins encapsulation in PLGA@PEG nanoparticles (NPs) did not destroy its inherent properties and exhibit more potent neuroprotective properties. An-NPs were nontoxic to SH-SY5Y cells and increased their cell viability against Aß1-42 by its free radical scavenging characteristics and abrogated ROS generation via the p38-MAPK/JNK pathways accompanied by induction of endogenous nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase 1 (HO-1). Comparative to native bulk anthocyanins, An-NPs effectively attenuated Alzheimer's markers like APP (amyloid precursor protein), BACE-1 (beta-site amyloid precursor protein cleaving enzyme 1), neuroinflammatory markers such as p-NF-kB (phospho-nuclear factor kappa B), TNF-α (tumor necrosis factor) and iNOS (inducible nitric oxide synthase) and neuroapoptotic markers including Bax, Bcl2, and Caspase-3 protein expressions accompanied by neurodegeneration against Aß1-42 in SH-SY5Y cell lines. CONCLUSIONS: Overall, this data not only confirmed the therapeutic potential of anthocyanins in reducing AD pathology but also offer an effective way to improve the efficiency of anthocyanins through the use of nanodrug delivery systems.

Melatonin Stimulates the SIRT1/Nrf2 Signaling Pathway Counteracting Lipopolysaccharide (LPS)-Induced Oxidative Stress to Rescue Postnatal Rat Brain.

AIMS: Lipopolysaccharide (LPS) induces oxidative stress and neuroinflammation both in vivo and in vitro. Here, we provided the first detailed description of the mechanism of melatonin neuroprotection against LPS-induced oxidative stress, acute neuroinflammation, and neurodegeneration in the hippocampal dentate gyrus (DG) region of the postnatal day 7 (PND7) rat brain. METHODS: The neuroprotective effects of melatonin against LPS-induced neurotoxicity were analyzed using multiple research techniques, including Western blotting, immunofluorescence, and enzyme-linked immunosorbent assays (ELISAs) in PND7 rat brain homogenates and BV2 cell lysates in vitro. We also used EX527 to inhibit silent information regulator transcript-1 (SIRT1). RESULTS: A single intraperitoneal (i.p) injection of LPS to PND7 rats significantly induced glial cell activation, acute neuroinflammation, reactive oxygen species (ROS) production and apoptotic neurodegeneration in hippocampal DG region after 4 h. However, the coadministration of melatonin significantly inhibited both LPS-induced acute neuroinflammation and apoptotic neurodegeneration and improved synaptic dysfunction in the hippocampal DG region of PND7 rats. Most importantly, melatonin stimulated the SIRT1/Nrf2 (nuclear factor-erythroid 2-related factor 2) signaling pathway to reduce LPS-induced ROS generation. The beneficial effects of melatonin were further confirmed in LPS-stimulated BV2 microglia cell lines in vitro using EX527 as an inhibitor of SIRT1. LPS-induced oxidative stress, Nrf2 inhibition, and neuroinflammation are SIRT1-dependent in BV2 microglia cell lines. CONCLUSION: These results demonstrated that melatonin treatment rescued the hippocampal DG region of PND7 rat brains against LPS-induced oxidative stress damage, acute neuroinflammation, and apoptotic neurodegeneration via SIRT1/Nrf2 signaling pathway activation.

Anthocyanins abrogate glutamate-induced AMPK activation, oxidative stress, neuroinflammation, and neurodegeneration in postnatal rat brain.

BACKGROUND: Glutamate-induced excitotoxicity, oxidative damage, and neuroinflammation are believed to play an important role in the development of a number of CNS disorders. We recently reported that a high dose of glutamate could induce AMPK-mediated neurodegeneration in the postnatal day 7 (PND7) rat brain. Yet, the mechanism of glutamate-induced oxidative stress and neuroinflammation in the postnatal brain is not well understood. Here, we report for the first time the mechanism of glutamate-induced oxidative damage, neuroinflammation, and neuroprotection by polyphenolic anthocyanins in PND7. METHODS: PND7 rat brains, SH-SY5Y, and BV2 cells treated either alone with glutamate or in combination with anthocyanins and compound C were examined with Western blot and immunofluorescence techniques. Additionally, reactive oxygen species (ROS) assay and other ELISA kit assays were employed to know the therapeutic efficacy of anthocyanins against glutamate. RESULTS: A single injection of glutamate to developing rats significantly increased brain glutamate levels, activated and phosphorylated AMPK induction, and inhibited nuclear factor-E2-related factor 2 (Nrf2) after 2, 3, and 4 h in a time-dependent manner. In contrast, anthocyanin co-treatment significantly reduced glutamate-induced AMPK induction, ROS production, neuroinflammation, and neurodegeneration in the developing rat brain. Most importantly, anthocyanins increased glutathione (GSH and GSSG) levels and stimulated the endogenous antioxidant system, including Nrf2 and heme oxygenase-1 (HO-1), against glutamate-induced oxidative stress. Interestingly, blocking AMPK with compound C in young rats abolished glutamate-induced neurotoxicity. Similarly, all these experiments were replicated in SH-SY5Y cells by silencing AMPK with siRNA, which suggests that AMPK is the key mediator in glutamate-induced neurotoxicity. CONCLUSIONS: Here, we report for the first time that anthocyanins can potentially decrease glutamate-induced neurotoxicity in young rats. Our work demonstrates that glutamate is toxic to the developing rat brain and that anthocyanins can minimize the severity of glutamate-induced neurotoxicity in an AMPK-dependent manner.

Hypoxia inducible factor 2 alpha inhibits hepatocellular carcinoma growth through the transcription factor dimerization partner 3/ E2F transcription factor 1-dependent apoptotic pathway.

UNLABELLED: Hypoxia inducible factors (HIFs) are activated in many tumors and show either promoter or suppressor activity, depending on tumor cell biology and background. However, the role of HIF member HIF-2α remains unclear in hepatocellular carcinoma (HCC). Here, HIF-2α expression was measured in HCC and paired peritumoral tissues by quantitative real-time polymerase chain reaction, western blotting, and immunofluorescence assays, and the clinical significance was explored in 246 HCC patients. In cell culture, HIF-2α levels were up-regulated or down-regulated by use of expression or short hairpin RNA recombinant plasmid, respectively. Cells were analyzed by immunoblotting, chromatin immunoprecipitation coupled with microarray, coimmunoprecipitation, and immunohistochemical staining. In vivo tumor growth was analyzed in nude mice. We found that the average expression of HIF-2α was relatively low in HCC tissues, and the decreased level was associated with lower overall survival (P=0.006). High HIF-2α expression in HCC cells induced higher levels of apoptosis and expression of proapoptotic proteins and inhibited cell and tumor growth. Furthermore, HIF-2α inhibited expression of the novel target gene, transcription factor dimerization partner 3 (TFDP3). TFDP3 protein was found to bind with E2F transcription factor 1 (E2F1) and inhibit its transcriptional activity through both p53-dependent and -independent pathways. Reintroduction of TFDP3 expression reversed HIF-2α-induced apoptosis. CONCLUSIONS: Data gathered from cell lines, tumorigenicity studies, and primary HCC samples demonstrate a negative role of HIF-2α in tumors, which is mediated by the TFDP3/E2F1 pathway. Our study provides evidence supporting a possible tumor-suppressor role for HIF-2α and has uncovered a mechanism that links HIF-2α to a fundamental biological regulator, E2F1.

Yes-associated protein regulates the hepatic response after bile duct ligation.

UNLABELLED: Human chronic cholestatic liver diseases are characterized by cholangiocyte proliferation, hepatocyte injury, and fibrosis. Yes-associated protein (YAP), the effector of the Hippo tumor-suppressor pathway, has been shown to play a critical role in promoting cholangiocyte and hepatocyte proliferation and survival during embryonic liver development and hepatocellular carcinogenesis. Therefore, the aim of this study was to examine whether YAP participates in the regenerative response after cholestatic injury. First, we examined human liver tissue from patients with chronic cholestasis. We found more-active nuclear YAP in the bile ductular reactions of primary sclerosing cholangitis and primary biliary cirrhosis patient liver samples. Next, we used the murine bile duct ligation (BDL) model to induce cholestatic liver injury. We found significant changes in YAP activity after BDL in wild-type mice. The function of YAP in the hepatic response after BDL was further evaluated with liver-specific Yap conditional deletion in mice. Ablating Yap in the mouse liver not only compromised bile duct proliferation, but also enhanced hepatocyte necrosis and suppressed hepatocyte proliferation after BDL. Furthermore, primary hepatocytes and cholangiocytes isolated from Yap-deficient livers showed reduced proliferation in response to epidermal growth factor in vitro. Finally, we demonstrated that YAP likely mediates its biological effects through the modulation of Survivin expression. CONCLUSION: Our data suggest that YAP promotes cholangiocyte and hepatocyte proliferation and prevents parenchymal damage after cholestatic injury in mice and thus may mediate the response to cholestasis-induced human liver disease.