Protection of p-Coumaric acid against chronic stress-induced neurobehavioral deficits in mice via activating the PKA-CREB-BDNF pathway.

There is a body of evidence to suggest that chronic stress modulates neurochemical homeostasis, alters neuronal structure, inhibits neurogenesis and contributes to development of mental disorders. Chronic stress-associated mental disorders present common symptoms of cognitive impairment and depression with complex disease mechanisms. P-coumaric acid (p-CA), a natural phenolic compound, is widely distributed in vegetables, cereals and fruits. p-CA exhibits a wide range of health-related effects, including anti-oxidative-stress, anti-mutagenesis, anti-inflammation and anti-cancer activities. The current study aims to evaluate the therapeutic potential of p-CA against stress-associated mental disorders. We assessed the effect of p-CA on cognitive deficits and depression-like behavior in mice exposed to chronic restraint stress (CRS); we used network pharmacology, biochemical and molecular biological approaches to elucidate the underlying molecular mechanisms. CRS exposure caused memory impairments and depression-like behavior in mice; p-CA administration attenuated these CRS-induced memory deficits and depression-like behavior. Network pharmacology analysis demonstrated that p-CA was possibly involved in multiple targets and a variety of signaling pathways. Among them, the protein kinase A (PKA) - cAMP-response element binding protein (CREB) - brain derived neurotrophic factor (BDNF) signaling pathway was predominant and further characterized. The levels of PKA, phosphorylated CREB (pCREB) and BDNF were significantly lowered in the hippocampus of CRS mice, suggesting disruption of the PKA-CREB-BDNF signaling pathway; p-CA treatment restored the signaling pathway. Furthermore, CRS upregulated expression of proinflammatory cytokines in hippocampus, while p-CA reversed the CRS-induced effects. Our findings suggest that p-CA will offer therapeutic benefit to patients with stress-associated mental disorders.

Chinese medicine, Qijudihuang pill, mediates cholesterol metabolism and regulates gut microbiota in high-fat diet-fed mice, implications for age-related macular degeneration.

Background: Traditional Chinese Medicines have been used for thousands of years but without any sound empirical basis. One such preparation is the Qijudihuang pill (QP), a mixture of eight herbs, that has been used in China for the treatment of various conditions including age-related macular degeneration (AMD), the most common cause of blindness in the aged population. In order to explain the mechanism behind the effect of QP, we used an AMD model of high-fat diet (HFD) fed mice to investigate cholesterol homeostasis, oxidative stress, inflammation and gut microbiota. Methods: Mice were randomly divided into three groups, one group was fed with control diet (CD), the other two groups were fed with high-fat-diet (HFD). One HFD group was treated with QP, both CD and the other HFD groups were treated with vehicles. Tissue samples were collected after the treatment. Cholesterol levels in retina, retinal pigment epithelium (RPE), liver and serum were determined using a commercial kit. The expression of enzymes involved in cholesterol metabolism, inflammation and oxidative stress was measured with qRT-PCR. Gut microbiota was analyzed using 16S rRNA sequencing. Results: In the majority of the lipid determinations, analytes were elevated by HFD but this was reversed by QP. Cholesterol metabolism including the enzymes of bile acid (BA) formation was suppressed by HFD but again this was reversed by QP. BAs play a major role in signaling between host and microbiome and this is disrupted by HFD resulting in major changes in the composition of colonic bacterial communities. Associated with these changes are predictions of the metabolic pathway complexity and abundance of individual pathways. These concerned substrate breakdowns, energy production and the biosynthesis of pro-inflammatory factors but were changed back to control characteristics by QP. Conclusion: We propose that the ability of QP to reverse these HFD-induced effects is related to mechanisms acting to lower cholesterol level, oxidative stress and inflammation, and to modulate gut microbiota.

Association of Nutrients, Specific Dietary Patterns, and Probiotics with Age-related Macular Degeneration.

Age-related macular degeneration (AMD) is a complex disease that mainly affects people over 50 years of age. Even though management of the vascularisation associated with the "wet" form of AMD is effective using anti-VEGF drugs, there is currently no treatment for the "dry" form of AMD. Given this, it is imperative to develop methods for disease prevention and treatment. For this review, we searched scientific articles via PubMed and Google Scholar, and considered the impact of nutrients, specific dietary patterns, and probiotics on the incidence and progression of AMD. Many studies revealed that regular consumption of foods that contain ω-3 fatty acids is associated with a lower risk for late AMD. Particular dietary patterns, such as the Mediterranean diet that contains ω-3 FAs-rich foods (nuts, olive oil, and fish), seem to be protective against AMD progression compared to Western diets that are rich in fats and carbohydrates. Furthermore, randomized controlled trials that investigated the role of nutrient supplementation in AMD have shown that treatment with antioxidants, such as lutein/zeaxanthin, zinc, and carotenoids, may be effective against AMD progression. More recent studies have investigated the association of the antioxidant properties of gut bacteria, such as Bacteroides and Eysipelotrichi, with lower AMD risk in individuals whose microbiota is enriched with them. These are promising fields of research that may yield the capacity to improve the quality of life for millions of people, allowing them to live with a clear vision for longer and avoiding the high cost of vision-saving surgery.

Evaluation of okadaic acid toxicity in human retinal cells and zebrafish retinas.

Okadaic acid (OA, C44H68O13) is a neurotoxin and phosphatase inhibitor produced by several dinoflagellate species. OA is widely known to accumulate in black sponges and is associated with seafood poisoning. Humans can be exposed to OA by consuming contaminated shellfish that have accumulated toxins during algal blooms. Evidence from in vitro and in vivo studies demonstrate that OA exposure causes neurotoxicity in addition to diarrheal syndrome. It is unclear whether exposure to OA affects retinal function, a part of the central nervous system. We evaluated the toxicity of OA in human retinal pigment epithelial cells (ARPE-19) and in zebrafish retinas. Cell-based assays determined that OA significantly decreased cell viability in a dose-dependent manner and increased oxidative stress, inflammation and cell death compared to the untreated control group. In the in vivo study, zebrafish embryos at 24 h post fertilization (hpf) were treated with/without OA for four days, endpoint measurements including mortality, malformations, delayed hatching, altered heartbeat and reduced movement were performed. OA exposure increased mortality, decreased hatching, heartbeat rate, and caused morphological abnormalities. OA exposure also markedly decreased the expression of antioxidant genes and a significantly increased inflammation as well as evoking a loss of photoreceptors in zebrafish embryos. The data suggest that consuming OA-contaminated seafood can induce retinal toxicity.

Bioinformatical and Biochemical Analyses on the Protective Role of Traditional Chinese Medicine against Age-Related Macular Degeneration.

PURPOSE: Age-related macular degeneration (AMD) is the commonest cause of permanent vision loss in the elderly. Traditional Chinese medicine (TCM) has long been used to treat AMD, although the underlying functional mechanisms are not understood. This study aims to predict the active ingredients through screening the chemical ingredients of anti-AMD decoction and to elucidate the underlying mechanisms. METHODS: We collected the prescriptions for effective AMD treatment with traditional Chinese medicine and screened several Chinese medicines that were used most frequently in order to compose "anti-AMD decoction." The pharmacologically active ingredients and corresponding targets in this anti-AMD decoction were mined using the Traditional Chinese Medicine Systems Pharmacology (TCMSP) database. Subsequently, the AMD-related targets were identified through the GeneCards database. Network pharmacology was performed to construct the visual network of anti-AMD decoction-AMD protein-protein interaction (PPI). Further, the Autodock software was adopted for molecular docking on the core active ingredients and core targets. The function of core ingredients against oxidative stress and inflammation in retinal pigment epithelial cells was assessed using biochemical assays. RESULTS: We screened out 268 active ingredients in anti-AMD decoction corresponding to 258 ingredient targets, combined with 2160 disease targets in AMD, and obtained 129 drug-disease common targets. The key core proteins were predominantly involved in inflammation. Furthermore, molecular docking showed that four potential active ingredients (Quercetin, luteolin, naringenin and hederagenin) had good affinity with the core proteins, IL-6, TNF, VEGFA and MAPK3. Quercetin, luteolin and naringenin demonstrated capacities against oxidative stress and inflammation in human retinal pigment epithelial cells. CONCLUSIONS: The data suggests that anti-AMD decoction has multiple functional components and targets in treating AMD, possibly mediated by suppression of oxidative stress and inflammation.

An update on the functional roles of long non­coding RNAs in ischemic injury (Review).

Ischemic injuries result from ischemia and hypoxia in cells. Tissues and organs receive an insufficient supply of nutrients and accumulate metabolic waste, which leads to the development of inflammation, fibrosis and a series of other issues. Ischemic injuries in the brain, heart, kidneys, lungs and other organs can cause severe adverse effects. Acute renal ischemia induces acute renal failure, heart ischemia induces myocardial infarction and cerebral ischemia induces cerebrovascular accidents, leading to loss of movement, consciousness and possibly, life­threatening disabilities. Existing evidence suggests that long non­coding RNAs (lncRNAs) are regulatory sequences involved in transcription, post­transcription, epigenetic regulation and multiple physiological processes. lncRNAs have been shown to be differentially expressed following ischemic injury, with the severity of the ischemic injury being affected by the upregulation or downregulation of certain types of lncRNA. The present review article provides an extensive summary of the functional roles of lncRNAs in ischemic injury, with a focus on the brain, heart, kidneys and lungs. The present review mainly summarizes the functional roles of lncRNA MALAT1, lncRNA MEG3, lncRNA H19, lncRNA TUG1, lncRNA NEAT1, lncRNA AK139328 and lncRNA CAREL, among which lncRNA MALAT1, in particular, plays a crucial role in ischemic injury and is currently a hot research topic.

MiR-29c-3p May Promote the Progression of Alzheimer's Disease through BACE1.

The aim of this study was to explore the specific role of miR-29c-3p in Alzheimer's disease (AD). Animal models of AD were established by injecting streptozotocin (STZ) into mice through the lateral ventricle, while cell models of AD were induced by 10 µM ß-amyloid (Aß). We detected miR-29c-3p and ß-site amyloid precursor protein cleaving enzyme 1 (BACE1) contents and measured AD cell proliferation and apoptosis. A low miR-29c-3p level and a high BACE1 level were detected in the brain tissue of AD animal models and AD cell models. Aß-processed cells had markedly lower proliferation activity, higher apoptosis, increased phosphorylation of tau protein was over phosphorylated, but the overexpression of miR-29c-3p or the silencing of BACE1 significantly enhanced the cell proliferation activity and reduced cell apoptosis by regulating the contents of related proteins. Inhibition of miR-29c-3p or overexpression of BACE1 aggravated Aß-induced side effects. We used Targetscan7.2 to predict the downstream target genes of miR-29c-3p. Then, we detected that there were target binding sites between miR-29c-3p and BACE1. The rescue experiment identified BACE1 as a functional target for miR-29c-3p. AD leads to decreased miR-29c-3p level and increased BACE1 level. MiR-29c-3p has specific binding sites with the 3'-untranslated region (3'-UTR) of BACE1 and thus negatively regulates the BACE1 level, thereby affecting the progression of AD.

miR-590-3 and SP1 Promote Neuronal Apoptosis in Patients with Alzheimer's Disease via AMPK Signaling Pathway.

Alzheimer's disease (AD) is a progressive neurological degenerative illness with a hidden onset. Its pathogenesis is complicated, although with molecular biology research on cancer and targeted research on pathogenic mechanisms, good progress has not yet been made. Therefore, this work built a multifactor-driven neuronal apoptosis dysfunction module for the purpose of probing its underlying pathogenic mechanisms. We performed differential expression analysis, coexpression analysis, enrichment analysis, and hypergeometric tests to calculate the underlying regulatory effects of multifactors on the modules by the way of the whole gene expression profile of AD and identify a series of ncRNA (miR-320a) and TF (NFKB1). Additionally, we screened 10 modules corresponding to the Hub gene, which tend to regulate the physiological progress of inflammation, regulation of autophagy, cerebral cortex neuron differentiation, glial cell apoptotic, and so on. Meanwhile, Alzheimer's disease is triggered by signaling pathways such as the MPK signaling pathway. In this study, a dysfunction module is utilized to verify that miR-590-3 and SP1 motility factors can regulate neurons in Alzheimer's disease through the MPK signaling pathway, not only providing new insights into the pathogenesis of Alzheimer's disease but also laying a solid theoretical foundation for the biologists to further cure Alzheimer's disease.

Gypenosides Alleviate Cone Cell Death in a Zebrafish Model of Retinitis Pigmentosa.

Retinitis pigmentosa (RP) is a group of visual disorders caused by mutations in over 70 genes. RP is characterized by initial degeneration of rod cells and late cone cell death, regardless of genetic abnormality. Rod cells are the main consumers of oxygen in the retina, and after the death of rod cells, the cone cells have to endure high levels of oxygen, which in turn leads to oxidative damage and cone degeneration. Gypenosides (Gyp) are major dammarane-type saponins of Gynostemma pentaphyllum that are known to reduce oxidative stress and inflammation. In this project we assessed the protective effect of Gyp against cone cell death in the rpgrip1 mutant zebrafish, which recapitulate the classical pathological features found in RP patients. Rpgrip1 mutant zebrafish were treated with Gyp (50 µg/g body weight) from two-months post fertilization (mpf) until 6 mpf. Gyp treatment resulted in a significant decrease in cone cell death compared to that of untreated mutant zebrafish. A markedly low level of reactive oxygen species and increased expression of antioxidant genes were detected in Gyp-incubated mutant zebrafish eyes compared to that of untreated mutant zebrafish. Similarly, the activities of catalase and superoxide dismutase and the level of glutathione were significantly increased in Gyp-treated mutant zebrafish eyes compared to that of untreated mutant zebrafish. Gyp treatment also decreased endoplasmic reticulum stress in rpgrip1 mutant eyes. Expression of proinflammatory cytokines was also significantly decreased in Gyp-treated mutant zebrafish eyes compared to that of untreated mutant zebrafish. Network pharmacology analysis demonstrated that the promotion of cone cell survival by Gyp is possibly mediated by multiple hub genes and associated signalling pathways. These data suggest treatment with Gyp will benefit RP patients.

Propofol attenuates mast cell degranulation via inhibiting the miR-221/PI3K/Akt/Ca2+ pathway.

The aim of the present study was to investigate the effect of propofol on immunoglobulin (Ig)E-activated mast cell degranulation and explore the underlying mechanisms responsible. RBL-2H3 cells were treated with propofol for at a variety of concentrations and different amounts of time. Cell viability was assessed using an MTT assay and microRNA (miR)-221 expression was quantified using reverse transcription-quantitative polymerase chain reaction. RBL-2H3 cells were transfected with miR-221 mimic or a negative control and degranulation, including the release of ß-hexosaminidase and histamine, was evaluated using an ELISA kit. The effect of miR-221 overexpression on the phosphorylation of protein kinase B (Akt) was detected using western blotting and extracellular Ca2+ influx was measured via afura-2 assay. The phosphoinositide 3-kinase(PI3K) inhibitor LY294002 was used to investigate the association between PI3K/Akt signaling and Ca2+ influx in the presence of propofol. The results demonstrated that propofol treatment suppressed RBL-2H3 cell proliferation in a dose- and time-dependent manner. Propofol inhibited miR-221 expression in a dose-dependent manner compared with the control group; however, the inhibitive effect was significantly abrogated following transfection with miR-221 mimics. Furthermore, ß-hexosaminidase and histamine release, PI3K/Akt signaling and Ca2+ influx were decreased following propofol application. miR-221 overexpression markedly ameliorated the suppressive effect of propofol. Treatment with LY294002 reversed the propofol-induced decrement of Ca2+ influx on IgE-mediated RBL-2H3 cells, suggesting an association between PI3K/Akt signaling and Ca2+ influx. In conclusion, the results of the present study suggest that propofol treatment attenuates mast cell degranulation via inhibiting the miR-221/PI3K/Akt/Ca2+ pathway. These results indicate that propofol may have a potential therapeutic effect as a treatment for allergic diseases.

BACE1 in the retina: a sensitive biomarker for monitoring early pathological changes in Alzheimer's disease.

Because of a lack of sensitive biomarkers, the diagnosis of Alzheimer's disease (AD) cannot be made prior to symptom manifestation. Therefore, it is crucial to identify novel biomarkers for the presymptomatic diagnosis of AD. While brain lesions are a major feature of AD, retinal pathological changes also occur in patients. In this study, we investigated the temporal changes in ß-site APP-cleaving enzyme 1 (BACE1) expression in the retina and brain to determine whether it could serve as a suitable biomarker for early monitoring of AD. APP/PS-1 transgenic mice, 3, 6 and 8 months of age, were used as an experimental group, and age-matched C57/BL6 wild-type mice served as the control group. In the Morris water maze test, there were no significant differences in escape latency or in the number of crossings in the target area among mice of different ages. Compared with wild-type mice, no changes in learning or memory abilities were detected in transgenic mice at 3 months of age. However, compared with wild-type mice, the escape latency was significantly increased in transgenic mice at 6 months, starting on day 3, and at 8 months, starting on day 2, during Morris water maze training. In addition, the number of crossings of the target area was significantly decreased in transgenic mice. The learning and memory abilities of transgenic mice were further worsened at 8 months of age. Immunohistochemical staining revealed no BACE1 plaques in wild-type mice at 3, 6 or 8 months or in transgenic mice at 3 months, but they were clearly found in the entorhinal cortex, hippocampus and prefrontal cortex of transgenic mice at 6 and 8 months. BACE1 expression was not detected in the retina of wild-type mice at 3 months, but weak BACE1 expression was detected in the ganglion cell layer, inner plexiform layer and outer plexiform layer at 6 and 8 months. In transgenic mice, BACE1 expression in the ganglion cell layer was increased at 3 months, and BACE1 expression in the ganglion cell layer, inner plexiform layer and outer plexiform layer was significantly increased at 6 and 8 months, compared with age-matched wild-type mice. Taken together, these results indicate that changes in BACE1 expression appear earlier in the retina than in the brain and precede behavioral deficits. Our findings suggest that abnormal expression of BACE1 in the retina is an early pathological change in APP/PS-1 transgenic mice, and that BACE1 might have potential as a biomarker for the early diagnosis of AD in humans.

The correlation between rat retinal nerve fiber layer thickness around optic disc by using optical coherence tomography and histological measurements.

AIM: To explore the correlation between the retinal nerve fiber layer (RNFL) thickness by using optical coherence tomography (OCT) and by histological measurements in normal adult rats and optic nerve transected rats. METHODS: The RNFL thickness of 36 rats was scanned in a circle 3.46mm far from the optic disc by OCT. The two experimental groups were the normal group (n=20 rats) and the optic nerve transected group (n=16 rats). The latter group included 4 groups (n=4/group) surviving for 1 day, 3, 5 and 7 days. Then the RNFL thickness of the same retina area was also measured by NF-200 immunohistochemical staining method. Linear regression was used to analyze the correlation between the data obtained from these two methods. RESULTS: The RNFL thickness of normal right eyes around optic disc by OCT was 72.35±5.71µm and that of the left eyes was 72.65±5.88µm (P=0.074). The RNFL thickness of the corresponding histological section by immunohistochemistry was 37.54±4.05µm (right eyes) and 37.38±4.23µm (left eyes) (P=0.059). There was a good correlation between the RNFL thickness measured by OCT and that measured by histology (R(2)=0.8131). After optic nerve transection, the trend of the RNFL thickness was thinner with the prolonged survival time. The correlation of the thickness detected by the above two methods was approximately (R(2)=0.8265). Value of the RNFL thickness in rats around optic disc measured by OCT was obviously higher than that measured by common histological measurement in normal adult rats and optic nerve transected rats. CONCLUSION: The RNFL thickness measured by OCT has a strong correlation with that measured by histological method. Through OCT scanning, we found that the thickness of RNFL gradually becomes thinner in a time-dependent manner.