Apigenin intervenes in liver fibrosis by regulating PKM2-HIF-1α mediated oxidative stress.

Apigenin (API) is a natural flavonoid compound with antioxidant, anti fibrotic, anti-inflammatory and other effects, but there is limited research on the effect of API on liver fibrosis. This study aims to explore the effect and potential mechanism of API on liver fibrosis induced by CCl4 in mice. The results indicate that API reduces oxidative stress levels, inhibits hepatic stellate cell (HSC) activation, and exerts anti liver fibrosis effects by regulating the PKM2-HIF-1α pathway. We observed that API alleviated liver tissue pathological damage and collagen deposition in CCl4 induced mouse liver fibrosis model, promoting the recovery of liver function in mice with liver fibrosis. In addition, the API inhibits the transition of Pyruvate kinase isozyme type M2 (PKM2) from dimer to tetramer formation by regulating the EGFR-MEK1/2-ERK1/2 pathway, thereby preventing dimer from entering the nucleus and blocking PKM2-HIF-1α access. This change leads to a decrease in malondialdehyde (MDA) and Catalase (CAT) levels and an increase in glutathione (GSH), superoxide dismutase (SOD), glutathione peroxidase (GSH-PX) levels, as well as total antioxidant capacity (T-AOC) in the liver of liver fibrosis mice. At the same time, API downregulated the expression of α-smooth muscle actin (α-SMA), Vimentin and Desmin in the liver tissue of mice with liver fibrosis, inhibited the activation of HSC, and reduced collagen deposition. These results indicate that API can inhibit HSC activation and alleviate CCl4 induced liver fibrosis by inhibiting the PKM2-HIF-1α pathway and reducing oxidative stress, laying an important foundation for the development and clinical application of API as a novel drug for treating liver fibrosis.

FPR1: A critical gatekeeper of the heart and brain.

G protein-coupled receptors (GPCRs) are currently the most widely focused drug targets in the clinic, exerting their biological functions by binding to chemicals and activating a series of intracellular signaling pathways. Formyl-peptide receptor 1 (FPR1) has a typical seven-transmembrane structure of GPCRs and can be stimulated by a large number of endogenous or exogenous ligands with different chemical properties, the first of which was identified as formyl-methionine-leucyl-phenylalanine (fMLF). Through receptor-ligand interactions, FPR1 is involved in inflammatory response, immune cell recruitment, and cellular signaling regulation in key cell types, including neutrophils, neural stem cells (NSCs), and microglia. This review outlines the critical roles of FPR1 in a variety of heart and brain diseases, including myocardial infarction (MI), ischemia/reperfusion (I/R) injury, neurodegenerative diseases, and neurological tumors, with particular emphasis on the milestones of FPR1 agonists and antagonists. Therefore, an in-depth study of FPR1 contributes to the research of innovative biomarkers, therapeutic targets for heart and brain diseases, and clinical applications.

Modified Xiaoyao San reverses lipopolysaccharide-induced depression-like behavior through suppressing microglia M1 polarization via enhancing autophagy involved in PI3K/Akt/mTOR pathway in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Modified Xiaoyao San (MXYS), a clinical empirical modified formula based on famous traditional Chinese herbal prescription Xiaoyao San, according to the "yu syndrome" theory of traditional Chinese medicine. MXYS has been shown to be an excellent effective therapy for depression patients in clinic, but the antidepressant mechanisms remain unclear. AIM OF THE STUDY: A growing body of evidence indicates the microglia autophagy and M1 polarized microglia (proinflammatory phenotype)-mediated neuroinflammation act critical roles in the pathogenesis of depression. This study aimed to investigate whether MXYS exerts antidepressant efficacy through inhibition of M1 polarized microglia-mediated neuroinflammation and modulation of autophagy involved in PI3K/Akt/mTOR pathway. MATERIALS AND METHODS: In present research, the lipopolysaccharide (LPS)-induced depressive mice and LPS-stimulated N9 microglia cell line were utilized. Behavioral tests (sucrose preference, tail suspension and open field tests) were carried out to evaluate the antidepressant effect of MXYS. The neuronal damage was measured by Nissl's staining in LPS-treated mice. The proinflammatory cytokine levels, the autophagic markers, microglia M1 polarization as well as the PI3K/Akt/mTOR pathway related proteins of MXYS treatment were analyzed by ELISA kits, Western blot and immunofluorescence staining in vivo and vitro. Finally, the influence of autophagy antagonist (3-MA) on the protective effect of MXYS-containing serum in the LPS-stimulated N9 microglia was investigated. RESULTS: Treatment of LPS-induced depressive mice with MXYS significantly reversed depression-like behaviors, accompanied by reduction of proinflammatory cytokine levels (TNF-α, IL-1ß) and amelioration of neuronal damage in prefrontal cortex. MXYS suppressed microglia M1 polarization and promoted autophagy in prefrontal cortex and LPS-stimulated N9 cells. Importantly, the remarkable inhibitory effect of the MXYS-medicated serum on microglia M1 polarization was blocked by autophagy antagonist 3-MA in LPS-stimulated N9 cells. Meanwhile, the MXYS treatment exhibited an excellent inhibition effect of PI3K/Akt/mTOR pathway in vivo and vitro. CONCLUSION: Our research suggests that the antidepressant effect of MXYS in LPS-induced depressive mice may be related to alleviate neuroinflammation through suppression of microglia M1 polarization via enhancing autophagy involved in inactivation of the PI3K/Akt/mTOR pathway.

Melatonin Ameliorates Cisplatin-Induced Renal Tubular Epithelial Cell Damage through PPARα/FAO Regulation.

Previous studies revealed that melatonin ameliorated acute renal injury induced by cisplatin, but the mechanisms remain unclear. Peroxidase proliferative receptor α (PPARα) is considered the major regulator of fatty acid oxidation (FAO), which is an important source of energy for renal tubular epithelial cells. In this study, the aim was to investigate the role of melatonin in cisplatin-induced NRK-52E (rat renal tubular epithelial cell line) cell damage and the underlying mechanisms. We established a cisplatin-stimulated NRK-52E model in vitro. We assessed the levels of apoptotic proteins, including caspase-3, caspase-9, and B-cell lymphoma 2-associated X protein (Bax), as well as PPARα and FAO-related genes (Acadm, Acat1, Acsm2, Acsm3, PGC-1α, Pecr, Bdh2, and Echs1). Furthermore, we detected the effects of miR-21 and PPARα antagonist on the above indicators. We found that melatonin reduced the protein expression levels of caspase-3, caspase-9, and Bax, and increased the expression levels of the PPARα gene and protein and PPARα activity, as well as FAO-related genes, in NRK-52E cells. However, miR-21 mimics and PPARα antagonists partially antagonized the above effects of melatonin. Our data indicated that melatonin could alleviate cisplatin-induced cell damage through the upregulation of PPARα/FAO.

Adsorption of cadmium ions from simulated battery wastewater by polyethylene polyamine-modified activated carbon.

The objective of this work was to study the treatment of wastewater containing cadmium ions (Cd2+). Activated carbon (AC) was modified with potassium hydroxide (KOH) and polyethylene polyamine (PEPA). The structure and morphology of the modified AC was characterized. The effect of pH on adsorption was investigated, and the binary competitive adsorption and the reusability of the modified AC were studied. Subsequently the modified AC was used as an adsorbent for the removal of Cd2+ from wastewater. The adsorption capacity of optimized modified AC was 9.7 times that of unmodified AC. Kinetic adsorption curves were in accordance with pseudo-second-order kinetics, and the isothermal curves were in accordance with the Langmuir equation. The results indicate that the AC has potential in the treatment of the wastewater containing Cd2+ discharged from chemical plants during battery manufacturing.

Tandem mass tag-based quantitative proteomic analysis of the liver reveals potential protein targets of Xiaochaihutang in CUMS model of depression.

Depression is a global mental disorder disease and greatly threatened human health. Xiaochaihutang (XCHT) has been used successfully in treatment of depression for many years in China, but the mechanism is unclear. Using the chronic unpredictable mild stress (CUMS) mice model of depression, the present study aimed to reveal possible antidepressant mechanisms of XCHT from the perspective of liver by analyzing hepatic proteomics in mice. Bioinformatics analysis identified 31 differentially expressed proteins (DEPs), including 5 upregulated and 26 downregulated proteins, between the CUMS model and XCHT groups. The bile secretion pathway was found by KEGG pathway analysis of these DEPs. Four of the 31 differentially expressed proteins, including 2 active proteins involved in bile secretion, carbonic anhydrase 2 (CA2) and cystic fibrosis transmembrane conductance regulator (CFTR), were selected to verify their genes. Four genes (Cyp7a1, Fxr, Shp and Ntcp) related to bile acid synthesis and transport were further investigated by quantitative real-time polymerase chain reaction (qRT-PCR). Both biochemical tests and gene studies demonstrated that CUMS affected bile acid synthesis and transport, while XCHT regulated this pathway. The results indicated that there may be a potential relationship between CUMS induced depression and hepatic injury caused by increased bile acid, and also provide a novel insight to understand the underlying anti-depression mechanisms of XCHT.

Plant-derived antioxidants incorporated into active packaging intended for vegetables and fatty animal products: a review.

Nowadays, the food industry is focused on improving the shelf life of products by controlling lipid oxidation using natural antioxidants. The study of natural antioxidants is a field that attracts great interest because of their greater safety compared to synthetic ones. Plant-derived antioxidants being eco-friendly and effective are increasingly playing an important role in food preservation. When incorporated into active packaging, plant-derived antioxidants have no direct contact with foods, and will not change the colour or taste of the foods. They will, however, inhibit the development of rancidity, retard formation of toxic oxidation products, maintain nutritional quality, and prolong the shelf life of products. This review summarises research on the development of plant-derived antioxidants in food packaging. Antioxidants are found in plants such as green tea, olive leaves, ginkgo leaves, rosemary, Indian gooseberry, cinnamon, savoury, bay leaves, mango leaves, sage and clove etc. Antioxidants can scavenge free radicals and inhibit the activity of polyphenol oxidase. Therefore, they can inhibit lipid oxidation and browning of fruit and vegetables. These active substances can be obtained through extracting the plants using solvents with different polarities. The oxidation resistance of active substances can be determined by DPPH radical scavenging capacity, oxygen radical absorbance capacity, PPO enzyme inhibition capacity and other methods. In recent years, research on the preparation of food packaging with plant-derived antioxidants has also made significant progress. One development is to encapsulate plant-derived antioxidants such as tea polyphenols with capsules containing inorganic components. Thus, they can be blended with polyethylene granules and processed into active packaging film by industrial production methods such as melting, extrusion and blowing film. This research promotes the commercial application of active packaging incorporated with plant-derived antioxidants.

Bone progeria diminished the therapeutic effects of bone marrow mesenchymal stem cells on retinal degeneration.

Senescence is closely related to the occurrence of retinal degeneration. Recent studies have shown that bone marrow mesenchymal stem cells (BMMSCs) have significant therapeutic effects on retinal degeneration, While BMMSCs suffer from functional decline in bone aging. Whether senescence affects BMMSCs therapy on retinal degeneration remains unknown. Here, we applied the previously established bone progeria animal model, the senescence-accelerated mice-prone 6 (SAMP6) strain, and surprisingly discovered that SAMP6 mice demonstrated retinal degeneration at 6 months old. Furthermore, BMMSCs derived from SAMP6 mice failed to prevent MNU-induced retinal degeneration in vivo. As expected, BMMSCs from SAMP6 mice exhibited impairment in the differentiation capacities, compared to those from the age-matched senescence-accelerated mice-resistant 1 (SAMR1) strain. Moreover, BMMSCs from SAMR1 mice counteracted MNU-induced retinal degeneration, with increased expression of the retina survival hallmark, N-myc downstream regulated gene 2 (NDRG2). Taken together, these findings reveal that bone progeria diminished the therapeutic effects of BMMSC on retinal degeneration.

Effects of resveratrol on the levels of ATP, 5-HT and GAP-43 in the hippocampus of mice exposed to chronic unpredictable mild stress.

Growing evidence suggested that energy deficiency might be involved in the pathophysiological mechanism of depression. Energy deficiency, mainly results from mitochondrial damage, can lead to the dysfunction of synaptic neurotransmission, and further cause depressive-like behavior. The antidepressant effect of resveratrol had been widely demonstrated in previous studies; however, the underlying mechanism remains poorly understood. The present study aimed to investigate whether the antidepressant effects of resveratrol involved in the energy levels and neurotransmission in the hippocampus. We found that resveratrol and fluoxetine significantly attenuated depressive-like behaviors induced by chronic unpredictable mild stress (CUMS), which evidenced by the increased sucrose preference and the reduced immobility time in a forced swimming test. In addition, resveratrol increased hippocampal ATP levels, decreased Na+-K+-ATPase and pyruvate levels, and upregulated the levels of mitochondrial DNA (mtDNA), mRNA expression of sirtuin (SIRT)1 and peroxisome proliferator-activated receptor γ coactivator (PGC)1α. Furthermore, resveratrol and fluoxetine increased serotonin (5-HT) levels and downregulated the mRNA expression of 5-HT transporter (SERT) in the hippocampus. The decreased protein expression of growth-associated protein (GAP)-43 induced by CUMS was also ameliorated by resveratrol and fluoxetine. These findings demonstrated the antidepressant effects of resveratrol and suggested that resveratrol was able to promote mitochondrial biogenesis, enhance ATP and 5-HT levels, as well as upregulate GAP-43 expression in the hippocampus.

Transcriptomic analysis reveals the mechanism of sulfasalazine-induced liver injury in mice.

Liver injury is one of the main toxic effect of sulfasalazine (SASP). However, the toxicological mechanism of SASP-induced liver injury remains unclear. In the present study, the liver injury was induced by orally treatment with SASP for 4 weeks in mice. The hepatic mRNA profiles were detected by RNA sequencing and the differentially expressed genes (DEGs) were analyzed by bioinformatics methods. The elevated serum levels of alanine aminotransferase (ALT), alkaline phosphatase (ALP) and total bilirubin (TBIL), combined with the hepatic histopathological features verified that liver injury was successfully caused by SASP. Transcriptomic results showed that 187 genes (fold change > 1.5 and P < 0.05) were differentially expressed, of which 106 genes were up-regulated and 81 genes were down-regulated in SASP-treated group. Moreover, the further analysis showed that these 187 differentially expressed genes (DEGs) were enriched in 123 GO terms, which mainly including oxidation-reduction process, oxidoreductase activity and epoxygenase P450 pathway. KEGG pathway analysis showed 30 pathways including chemical carcinogenesis, retinol metabolism, arachidonic acid metabolism, linoleic acid metabolism and glutathione metabolism. Among these 187 DEGs, the top 22 hub genes were screened from network of protein-protein interaction (PPI) and verified by qRT-PCR. The results showed that the mRNA levels of hepatic drug-metabolizing enzymes, including cyp2b50, cyp2c50, cyp2c39, cyp2c38, cyp2c29, cyp2c54, cyp2c55, cyp2a5, gsta1, gsta2, gstt2, gstm2 and ephx1, were significantly up-regulated, while egfr and egr1 were down-regulated in SASP-treated group. Moreover, the mRNA levels of egfr and cyp2c55 exhibited a dose-dependent changes in SASP groups. Western blotting verified that the changes of protein levels of EGFR and CYP2C55 were consistent with mRNA levels. Considering that egfr has the highest score in PPI degree and cyp2c55 has the largest fold change in qPCR analysis, our present results suggested that the toxicological mechanisms of SASP-induced liver injury might be related to multi-biological processes and pathways, and egfr and cyp2c55 may play important roles in SASP-induced liver injury. The present study would be helpful for better understanding the hepatotoxic mechanism of SASP. However, the precise mechanism still needs further research.

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

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

miR-145-5p Acts as a Novel Tumor Suppressor in Hepatocellular Carcinoma Through Targeting RAB18.

Micro-RNAs play critical roles in initiation and progression of hepatocellular carcinoma. However, the biological role of microRNA-145-5p in hepatocellular carcinoma and how it works are still not clearly understood. Expression levels of microRNA-145-5p in hepatocellular carcinoma cell lines were examined by reverse transcription quantitative polymerase chain reaction. Cell counting kit-8, wound-healing assay, and flow cytometry assay were conducted to investigate the role of microRNA-145-5p von proliferation, migration, and apoptosis. Luciferase reporter assay and Western blot were performed to investigate the correlation between microRNA-145-5p and RAB18. We found microRNA-145-5p was downregulated in hepatocellular carcinoma cell lines compared to the normal cell line. Overexpression of microRNA-145-5p inhibited the proliferation and migration but promoted apoptosis of hepatocellular carcinoma cells in vitro. RAB18 was validated a target of microRNA-145-5p and ectopic expression of RAB18 can promote the proliferation and migration but inhibit apoptosis of hepatocellular carcinoma cells. These findings indicate that microRNA-145-5p functions as a novel tumor suppressor through targeting RAB18, suggesting that microRNA-145-5p might be a potential new therapeutic molecule for the treatment of hepatocellular carcinoma.

Paeoniflorin Ameliorates Fructose-Induced Insulin Resistance and Hepatic Steatosis by Activating LKB1/AMPK and AKT Pathways.

The present study aimed to evaluate the effects of paeoniflorin on insulin resistance and hepatic steatosis induced by fructose. Male Sprague-Dawley rats were fed 20% fructose drink for eight weeks. The insulin sensitivity, serum lipid profiles, and hepatic lipids contents were measured. The results showed that paeoniflorin significantly decreased serum insulin and glucagon levels, improved insulin sensitivity and serum lipids profiles, and alleviated hepatic steatosis in fructose-fed rats. Moreover, paeoniflorin enhanced the phosphorylation level of AMP-activated protein kinase (AMPK) and protein kinase B (PKB/AKT) and inhibited the phosphorylation of acetyl coenzyme A carboxylase (ACC)1 in liver. Paeoniflorin also increased the hepatic carnitine palmitoyltransferase (CPT)-1 mRNA and protein expression and decreased the mRNA expression of sterol regulatory element-binding protein (SREBP)1c, stearyl coenzyme A decarboxylase (SCD)-1 and fatty acid synthetase (FAS). Furthermore, we found that paeoniflorin significantly increased the heptatic protein expression of tumor suppressor serine/threonine kinase (LKB)1 but not Ca2+/CaM-dependent protein kinase kinase (CaMKK)ß. These results suggest that the protective effects of paeoniflorin might be involved in the activation of LKB1/AMPK and insulin signaling, which resulted in the inhibition of lipogenesis, as well as the activation of ß-oxidation and glycogenesis, thus ameliorated the insulin resistance and hepatic steatosis. The present study may provide evidence for the beneficial effects of paeoniflorin in the treatment of insulin resistance and non-alcoholic fatty liver.

Spike-timing-dependent plasticity enhanced synchronization transitions induced by autapses in adaptive Newman-Watts neuronal networks.

In this paper, we numerically study the effect of spike-timing-dependent plasticity (STDP) on synchronization transitions induced by autaptic activity in adaptive Newman-Watts Hodgkin-Huxley neuron networks. It is found that synchronization transitions induced by autaptic delay vary with the adjusting rate Ap of STDP and become strongest at a certain Ap value, and the Ap value increases when network randomness or network size increases. It is also found that the synchronization transitions induced by autaptic delay become strongest at a certain network randomness and network size, and the values increase and related synchronization transitions are enhanced when Ap increases. These results show that there is optimal STDP that can enhance the synchronization transitions induced by autaptic delay in the adaptive neuronal networks. These findings provide a new insight into the roles of STDP and autapses for the information transmission in neural systems.

17ß-Estradiol Protects the Retinal Nerve Cells Suppressing TLR2 Mediated Immune-Inflammation and Apoptosis from Oxidative Stress Insult Independent of PI3K.

The excessive apoptosis of retinal nerve cells (RNCs) could cause a variety of retinal neurodegenerative diseases which could result in the irreversible blindness. In this study, the experiment models of H2O2 and light-induced oxidative insult in the retina of Sprague-Dawley (SD) rat were used. We demonstrated the role of toll-like receptor 2 (TLR2) in apoptosis and immune-inflammation induced by oxidative stress insult. Meanwhile, we also tried to elucidate the modulating mechanism of 17ß-estradiol (E2) resistant to TLR2 induced by oxidative stress insult. The cell apoptosis induced by oxidative stress was examined by annexin V-FITC/propidium iodide (PI) assay using flow cytometry and the expressions of TLR2 and inflammatory cytokines were determined by real-time PCR and western blotting. Peptidoglycan (PGN) as the ligand of TLR2 and small interfering RNAs of TLR2 (siTLR2) were used to determine the role of TLR2. From the results, firstly, we demonstrated that E2 could reduce the expressions of TLR2 and inflammatory cytokines including TNF-ɑ, IFN-γ, and IL-1ß induced by oxidative stress; secondly, the phosphoinositide 3-kinase (PI3K) could not influence the effect of E2 on reducing TLR2 expression induced by H2O2 in RNCs; thirdly, PGN could promote the damage effect of H2O2 by transforming RNCs from late apoptosis to necrosis, however, E2 could decrease the cell apoptosis mediated by PGN; and finally, the apoptosis of RNCs and the expressions of the inflammatory cytokines induced by H2O2 administration were significantly inhibited after TLR2 interference. In summary, E2 reduces the TLR2-mediated immune-inflammation, thereby protecting RNCs against oxidative stress-induced apoptosis via a PI3K-independent signaling pathway. The present results provide evidence that inhibiting of TLR2-mediated immune-inflammation might be a possible therapeutic way to exert auxiliary role on E2 neuroprotection.

17ß-estradiol ameliorates light-induced retinal damage in Sprague-Dawley rats by reducing oxidative stress.

Oxidative stress is considered as a major cause of light-induced retinal neurodegeneration. The protective role of 17ß-estradiol (ßE2) in neurodegenerative disorders is well known, but its underlying mechanism remains unclear. Here, we utilized a light-induced retinal damage model to explore the mechanism by which ßE2 exerts its neuroprotective effect. Adult male and female ovariectomized (OVX) rats were exposed to 8,000 lx white light for 12 h to induce retinal light damage. Electroretinogram (ERG) assays and hematoxylin and eosin (H&E) staining revealed that exposure to light for 12 h resulted in functional damage to the rat retina, histological changes, and retinal neuron loss. However, intravitreal injection (IVI) of ßE2 significantly rescued this impaired retinal function in both female and male rats. Based on the level of malondialdehyde (MDA) production (a biomarker of oxidative stress), an increase in retinal oxidative stress followed light exposure, and ßE2 administration reduced this light-induced oxidative stress. Quantitative reverse-transcriptase (qRT)-PCR indicated that the messenger RNA (mRNA) levels of the antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (Gpx) were downregulated in female OVX rats but were upregulated in male rats after light exposure, suggesting a gender difference in the regulation of these antioxidant enzyme genes in response to light. However, ßE2 administration restored or enhanced the SOD and Gpx expression levels following light exposure. Although the catalase (CAT) expression level was insensitive to light stimulation, ßE2 also increased the CAT gene expression level in both female OVX and male rats. Further examination indicated that the antioxidant proteins thioredoxin (Trx) and nuclear factor erythroid 2-related factor 2 (Nrf2) are also involved in ßE2-mediated antioxidation and that the cytoprotective protein heme oxygenase-1 (HO-1) plays a key role in the endogenous defense mechanism against light exposure in a ßE2-independent manner. Taken together, we provide evidence that ßE2 protects against light-induced retinal damage via its antioxidative effect, and its underlying mechanism involves the regulation of the gene expression levels of antioxidant enzymes (SOD, CAT, and Gpx) and proteins (Trx and Nrf2). Our study provides conceptual evidence in support of estrogen replacement therapy for postmenopausal women to reduce the risk of age-related macular degeneration.

Dynamic magnetism of an iron(II)-chlorido spin chain and its hexametallic segment.

An air-stable iron(ii) chain compound [Fe(phen)(Cl)2]n (, phen = 1,10-phenanthroline) was prepared and exhibits intrachain ferromagnetic interactions as well as competing interchain antiferromagnetic interactions that are mediated by π-π stacking of the phen ligands, resulting in metamagnetic behaviour. The interchain interactions can be altered by changing the external magnetic field, and disparate magnetic dynamics was thus observed from zero to the critical field of 1500 Oe. Zero-field cooled (ZFC) and field-cooled (FC) magnetization and heat capacity measurements indicate that long-range antiferromagnetic ordering occurs at lower fields, and this ordering disappears when the external field is larger than 1500 Oe. The low-frequency ac susceptibility data are consistent with the exponential increase of the temperature-dependent dc data, indicating a Glauber-type dynamics under the field of 1500 Oe. Thus, is considered as a metamagnetic single-chain magnet. For further analysis, a discrete hexametallic segment of the chain, [Fe6(phen)6(Cl)12] (), was also isolated and was shown to possess a high-spin ground state and display slow magnetic relaxations like single-molecule magnets. Magnetic analysis using CONDON suggests weak ferromagnetic interactions between the metal centres. The polymeric compound can be viewed as being constructed using the hexametallic unit which is of a low energy barrier, suggesting the significance of intrachain ferromagnetic interactions in enhancing the spin-reversal energy barrier of the short chains.

Autophagy occurs within an hour of adenosine triphosphate treatment after nerve cell damage: the neuroprotective effects of adenosine triphosphate against apoptosis.

After hypoxia, ischemia, or inflammatory injuries to the central nervous system, the damaged cells release a large amount of adenosine triphosphate, which may cause secondary neuronal death. Autophagy is a form of cell death that also has neuroprotective effects. Cell Counting Kit assay, monodansylcadaverine staining, flow cytometry, western blotting, and real-time PCR were used to determine the effects of exogenous adenosine triphosphate treatment at different concentrations (2, 4, 6, 8, 10 mmol/L) over time (1, 2, 3, and 6 hours) on the apoptosis and autophagy of SH-SY5Y cells. High concentrations of extracellular adenosine triphosphate induced autophagy and apoptosis of SH-SY5Y cells. The enhanced autophagy first appeared, and peaked at 1 hour after treatment with adenosine triphosphate. Cell apoptosis peaked at 3 hours, and persisted through 6 hours. With prolonged exposure to the adenosine triphosphate treatment, the fraction of apoptotic cells increased. These data suggest that the SH-SY5Y neural cells initiated autophagy against apoptosis within an hour of adenosine triphosphate treatment to protect themselves against injury.

The involvement of PI3K-mediated and L-VGCC-gated transient Ca2+ influx in 17ß-estradiol-mediated protection of retinal cells from H2O2-induced apoptosis with Ca2+ overload.

Intracellular calcium concentration ([Ca(2+)]i) plays an important role in regulating most cellular processes, including apoptosis and survival, but its alterations are different and complicated under diverse conditions. In this study, we focused on the [Ca(2+)]i and its control mechanisms in process of hydrogen peroxide (H2O2)-induced apoptosis of primary cultured Sprague-Dawley (SD) rat retinal cells and 17ß-estradiol (ßE2) anti-apoptosis. Fluo-3AM was used as a Ca(2+) indicator to detect [Ca(2+)]i through fluorescence-activated cell sorting (FACS), cell viability was assayed using MTT assay, and apoptosis was marked by Hoechst 33342 and annexin V/Propidium Iodide staining. Besides, PI3K activity was detected by Western blotting. Results showed: a) 100 µM H2O2-induced retinal cell apoptosis occurred at 4 h after H2O2 stress and increased in a time-dependent manner, but [Ca(2+)]i increased earlier at 2 h, sustained to 12 h, and then recovered at 24 h after H2O2 stress; b) 10 µM ßE2 treatment for 0.5-24 hrs increased cell viability by transiently increasing [Ca(2+)]i, which appeared only at 0.5 h after ßE2 application; c) increased [Ca(2+)]i under 100 µM H2O2 treatment for 2 hrs or 10 µM ßE2 treatment for 0.5 hrs was, at least partly, due to extracellular Ca(2+) stores; d) importantly, the transiently increased [Ca(2+)]i induced by 10 µM ßE2 treatment for 0.5 hrs was mediated by the phosphatidylinositol-3-kinase (PI3K) and gated by the L-type voltage-gated Ca(2+) channels (L-VGCC), but the increased [Ca(2+)]i induced by 100 µM H2O2 treatment for 2 hrs was not affected; and e) pretreatment with 10 µM ßE2 for 0.5 hrs effectively protected retinal cells from apoptosis induced by 100 µM H2O2, which was also associated with its transient [Ca(2+)]i increase through L-VGCC and PI3K pathway. These findings will lead to better understanding of the mechanisms of ßE2-mediated retinal protection and to exploration of the novel therapeutic strategies for retina degeneration.

17ß-estradiol impedes Bax-involved mitochondrial apoptosis of retinal nerve cells induced by oxidative damage via the phosphatidylinositol 3-kinase/Akt signal pathway.

Oxidative stress leading to retinal nerve cells (RNCs) apoptosis is a major cause of neurodegenerative disorders of the retina. 17ß-Estradiol (E2) has been suggested to be a neuroprotective agent in the central nervous system; however, at present, the underlying mechanisms are not well understood, and the related research on the RNCs is less reported. Here, in order to investigate the protective role and mechanism of E2 against oxidative stress-induced damage on RNCs, the transmission electron microscopy and annexin V-FITC/propidium iodide assay were applied to detect the RNCs apoptosis. Western blot and real-time PCR were used to determine the expression of the critical molecules in Bcl-2 and caspase family associated with apoptosis. The transmission electron microscopy results showed that H(2)O(2) could induce typical features of apoptosis in RNCs, including formation of the apoptosome. E2 could, however, suppress the H(2)O(2)-induced morphological changes of apoptosis. Intriguingly, we observed E2-mediated phagocytic scavenging of apoptosome. In response to H(2)O(2)-induced apoptosis, Bax, acting as one of the pivotal pro-apoptotic members of Bcl-2 family, increased significantly, which directly resulted in an increased ratio of Bax to anti-apoptotic protein Bcl-2 (Bax/Bcl-2). Additionally, caspases 9 and 3, which are the critical molecules of the mitochondrial apoptosis pathway, were activated by H(2)O(2). In contrast, E2 exerted anti-apoptotic effects by reducing the expression of Bax to decrease the ratio of Bax/Bcl-2 and impeded the caspases 9/3 activation. Moreover, LY294002, a phosphatidylinositol 3-kinase (PI3K) inhibitor, could sharply block the effect of E2 in reducing the percentage of apoptotic cells resistance to H(2)O(2). And the attenuation of Bax, the reduced activities of caspases 9/3 and the impeded release of mitochondrial cytochrome c mediated by E2 resistance to H(2)O(2) damage were significantly retrieved by LY294002 administration. Taken together, E2 protects the RNCs against H(2)O(2)-induced apoptosis by significantly inhibiting the Bax-involved mitochondrial apoptosis via the activation of PI3K/Akt signal pathway.