Manganese-induced PINK1 S-nitrosylation exacerbates nerve cell damage by promoting ZNF746 repression of mitochondrial biogenesis.

Occupational exposure and non-occupational exposure to excessive levels of manganese (Mn) result in neuronal cell damage through mitochondrial dysfunction. The functional integrity of mitochondria is maintained by mitophagy and mitochondrial biogenesis. Although Mn-induced S-nitrosylation of PTEN-induced putative kinase 1 (PINK1) can interfere with mitophagy, its effect on mitochondrial biogenesis remains unclear. In this study, we established a rat model of Mn poisoning or "manganism" to examine the relationship between PINK1 S-nitrosylation and impairment of mitochondrial biogenesis, and found that treatment with 60 mg/kg Mn induced marked neurobehavioral abnormalities in rats and significantly increased the S-nitrosylation level of PINK1. We also found that the nuclear-encoded peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PPARGC1A)-mediated mitochondrial biogenesis was significantly upregulated in rats treated with 15 and 30 mg/kg Mn, and downregulated in rats treated with 60 mg/kg Mn. We further investigated the role of S-nitrosylated PINK1 and its molecular mechanism in the high-dose Mn-mediated impairment of mitochondrial biogenesis in primary cultured neurons treated with the nitric oxide synthase 2 (NOS2) inhibitor 1400 W. Our results revealed that the PPARGC1A-mediated mitochondrial biogenesis was upregulated in neurons treated with 100 µM, but downregulated in neurons treated with 200 µM Mn, which was similar to the in vivo results. However, treatment with 1400W could effectively prevent the 200 µM Mn-mediated impairment of mitochondrial biogenesis by suppressing nitric oxide (NO)-mediated PINK1 S-nitrosylation and rescuing Parkin-interacting substrate (PARIS, ZNF746) degradation, thereby upregulating mitochondrial biogenesis via PPARGC1A. These findings demonstrated that S-nitrosylation of PINK1 and subsequent prevention of ZNF746 degradation were crucial signaling processes involved in the Mn-mediated impairment of mitochondrial biogenesis, which might serve as an underlying mechanism of Mn-induced neurotoxicity. Furthermore, this study provided a reliable target for the prevention and treatment of manganism.

Ectopic Expression of a R2R3-MYB Transcription Factor Gene LjaMYB12 from Lonicera japonica Increases Flavonoid Accumulation in Arabidopsis thaliana.

Lonicera japonica Thunb. is a widely used medicinal plant and is rich in a variety of active ingredients. Flavonoids are one of the important components in L. japonica and their content is an important indicator for evaluating the quality of this herb. To study the regulation of flavonoid biosynthesis in L. japonica, an R2R3-MYB transcription factor gene LjaMYB12 was isolated and characterized. Bioinformatics analysis indicated that LjaMYB12 belonged to the subgroup 7, with a typical R2R3 DNA-binding domain and conserved subgroup 7 motifs. The transcriptional level of LjaMYB12 was proportional to the total flavonoid content during the development of L. japonica flowers. Subcellular localization analysis revealed that LjaMYB12 localized to the nucleus. Transactivation activity assay indicated that LjaMYB12 was a transcriptional activator. Then, ectopic expression of LjaMYB12 in Arabidopsis could increase PAL activity and flavonoid content and promote transcription of a range of flavonoid biosynthetic genes. Interestingly, the fold changes of downstream genes in the flavonoid biosynthetic pathway were significantly higher than that of the upstream genes, which suggested that LjaMYB12 may have different regulatory patterns for the upstream and downstream pathways of flavonoid biosynthesis. The results provided here will effectively facilitate the study of subgroup 7 MYBs and transcriptional regulation of flavonoid biosynthesis in L. japonica.

Effects of Long-Term Mineral Block Supplementation on Antioxidants, Immunity, and Health of Tibetan Sheep.

Tibetan sheep have been observed with mineral deficiencies and marginal deficiencies in Qinghai-Tibetan Plateau. Adequate amounts of essential minerals are critical to maximize the productivity and health of livestock. The objectives of this study were to evaluate the effects of 6 months of mineral block supplementation on the antioxidants, immunity, and health of Tibetan sheep. The study was conducted in Qinghai-Tibetan Plateau. The consumed values of mineral blocks were measured. Blood samples were collected at the end of the experiment to evaluate the trace elements, malondialdehyde (MDA) and glutathione (GSH) activities, and antioxidant enzyme activities. Additionally, levels of IgA, IgG, IgM, IL-2, IL-12, tumor necrosis factor-α (TNF-α), triiodothyronine (T3), tyroxine (T4), and insulin-like growth factor-1 (IGF-1) were determined. The toxic effects of the mineral block were also monitored. For Tibetan sheep, the average consumed value of mineral block was 13.09 g per day per sheep. Mineral block supplementation significantly increased the serum levels of Mn, Fe, and Se (P < 0.01), decreased the level of MDA (P < 0.05), and increased GSH activity (P < 0.05). Additionally, the mineral block-treated sheep blood had greater total antioxidative capacity (T-AOC) and total superoxide dismutase (T-SOD) activities (P < 0.01 or P < 0.05) than control sheep. Moreover, the mineral block supplementation improved the levels IgA, IgM, and IGF-1 (P < 0.01 or P < 0.05). Additionally, there were no significant histopathological changes in the organs of Tibetan sheep after long-term treatment with the mineral block. The results demonstrated that the mineral block was non-toxic and safe; the protective effects of the mineral block might be caused by an increase in the antioxidant defense system, as well as an increase in the benefits from immunity-related parameters.

Assessment of the anti-diarrhea function of compound Chinese herbal medicine Cangpo Oral Liquid.

BACKGROUND: Diarrhea is a big problem in piglets. Cangpo Oral Liquid (COL) is a compound of Chinese herbal medicine. The preparation was fed to piglets had diarrheal disease in order to determine its anti-diarrhea activity and potential applications in vivo. MATERIALS AND METHODS: The contents of Berberine hydrochloride, Magnolol and Honokiol in COL were performed on HPLC analysis. Organ bath was used to investigate the effect of COL on peristaltic reflexes and peristaltic waves in vitro. And anti-diarrhea activity of COL was evaluated in clinical. RESULTS: Thin layer chromatography (TLC) and HPLC analyses showed that the contents of Berberine hydrochloride, Magnolol and Honokiol in COL were 970µg/mL, 130µg/mL and 300µg/mL, respectively. Administration of the COL to the organ bath caused a concentration-dependent inhibition of intestinal peristalsis. When the COL concentration in the bath was cumulatively increased, the amplitude and frequency of the peristaltic waves was lowered. The result of clinical efficacy of COL was very effective to diarrheic piglets. COL can possibly inhibit the curve of peristaltic waves in vitro; and clinical trial showed a statistically significant therapeutic effect in vivo. CONCLUSION: In conclusion, COL can be used as an effective therapeutic agent. However, the ingredients, pharmacokinetics and specific signaling pathways of COL need to be further studied.

A 15-day oral dose toxicity study of aspirin eugenol ester in Wistar rats.

The subchronic toxicity of aspirin eugenol ester (AEE) was evaluated after 15-day intragastrically administration in rats at daily doses of 50, 1000, and 2000 mg/kg. AEE at low-dose showed no toxicity to the tested rats. Following repeated exposure to medium- or high-dose of AEE, apparent changes were observed in the levels of blood glucose, AST, ALP, ALT and TB in both male and female rats, and appeared to be dose-independent. There were no significant gender differences in most indexes of subchronic toxicity throughout the experimental period with the exception of food consumption and body weight. The no-observed-adverse-effect level (NOAEL) of AEE was considered to be 50 mg/kg/day under the present study conditions.

Molecular characterization and functional expression of the DSC1 channel.

Drosophila Sodium Channel 1 (DSC1) was predicted to encode a sodium channel based on a high sequence similarity with vertebrate and invertebrate sodium channel genes. However, BSC1, a DSC1 ortholog in Blattella germanica, was recently shown to encode a cation channel with ion selectivity toward Ca(2+). In this study, we isolated a total of 20 full-length cDNA clones that cover the entire coding region of the DSC1 gene from adults of Drosophila melanogaster by reverse transcription-polymerase chain reaction. Sequence analysis of the 20 clones revealed nine optional exons, four of which contain in-frame stop codons; and 13 potential A-to-I RNA editing sites. The 20 clones can be grouped into eight splice types and represent 20 different transcripts because of unique RNA editing. Three variants generated DSC1 currents when expressed in Xenopus oocytes. Like the BSC1 channel, all three functional DSC1 channels are permeable to Ca(2+) and Ba(2+), and also to Na(+) in the absence of external Ca(2+). Furthermore, the DSC1 channel is insensitive to tetrodotoxin, a potent and specific sodium channel blocker. Our study shows that DSC1 encodes a voltage-gated cation channel similar to the BSC1 channel in B. germanica. Extensive alternative splicing and RNA editing of the DSC1 transcripts suggest the molecular and functional diversity of the DSC1 channel.

An ion channel library for drug discovery and safety screening on automated platforms.

Ion channels represent the third largest class of targets in drug discovery after G-protein coupled receptors and kinases. In spite of this ranking, ion channels continue to be under exploited as drug targets compared with the other two groups for several reasons. First, with 400 ion channel genes and an even greater number of functional channels due to mixing and matching of individual subunits, a systematic collection of ion channel-expressing cell lines for drug discovery and safety screening has not been available. Second, the lack of high-throughput functional assays for ion channels has limited their use as drug targets. Now that automated electrophysiology has come of age and provided the technology to assay ion channels at medium to high throughput, we have addressed the need for a library of ion channel cell lines by constructing the Ion Channel Panel (ChanTest Corp., Cleveland, OH). From 400 ion channel genes, a collection of 82 of the most relevant human ion channels for drug discovery, safety, and human disease has been assembled.Each channel has been stably overexpressed in human embryonic kidney 293 or Chinese hamster ovary cells. Cell lines have been selected and validated on automated electrophysiology systems to facilitate cost-effective screening for safe and selective compounds at earlier stages in the drug development process. The screening and validation processes as well as the relative advantages of different screening platforms are discussed.

[Low-frequency tympanometry in normal neonates].

OBJECTIVE: To find the characteristic of tympanogram results obtained from normative neonates 2 - 7 days about low frequency (226 Hz) probe tone, and to determine the normative values for tympanometric variables. METHOD: Transient evoked otoacoustic emission (TEOAE) screening were performed by using AccuScreen Pro instrument for 135 neonates. Among them, 105 neonates passed the TEOAE screening in both ears. The 226 Hz probe tone tympanograms and their normative values were obtained from them using GSI-33 middle ear analyzer. RESULT: The 226 Hz tympanometric data for the 105 neonates (210 ears) passed the TEOAE screening in both ears showed a double-peaked tympanogram in 202 ears (96.19%), a single-peaked tympanogram in 8 ears (3.81%). For double-peaked tympanogram in 202 ears, the tympanometric normative values was below: the first peak admittance is (0.91 +/- 0.18)mmho, Tpp is about (18.02 +/- 12.26)daPa; the second peak admittance is (1.05 +/- 0.23)mmho, Tpp is about (-35.05 +/- 16.80) daPa; the admittance of notch between the two peaks is (0.74 +/- 2.57)mmho, its pressure is about (0.37 +/- 7.61) daPa. Vec is about (0.50 +/- 0.08)ml. CONCLUSION: The 226 Hz tympanograms obtained from this cohort may serve as a guide for evaluating middle ear function in neonates.