Antibacterial constituents from Antarctic fungus, Aspergillus sydowii SP-1.

One new alkaloid, named as acremolin C (1), was isolated from static culture of Antarctic fungus, Aspergillus sydowii SP-1, in an investigation of the antimicrobial constituents of this Antarctic microorganism, and its structure was determined by spectroscopic methods. Additionally, four known compounds, cyclo-(L-Trp-L-Phe) (2), 4-hydroxyphenylacetic acid (3), (7S)-(+)-hydroxysydonic acid (4) and (7S, 11S)-(+)-12-hydroxysydonic acid (5), were isolated and identified. Biological studies disclosed that compounds 2, 4 and 5 showed moderate inhibitions against methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant Staphylococcus epidermidis (MRSE) as comparing to tigecycline, while compound 1 displayed weak inhibition activities against MRSA and MRSE.

PPARγ agonists regulate bidirectional transport of amyloid-ß across the blood-brain barrier and hippocampus plasticity in db/db mice.

BACKGROUND AND PURPOSE: There is emerging evidence suggesting that abnormal transport of amyloid-ß (Aß) across the blood-brain barrier (BBB) is involved in diabetes-associated cognitive decline. We investigated whether PPARγ agonists restore Aß transport across the BBB and hippocampal plasticity in db/db mice. EXPERIMENTAL APPROACH: Efflux and influx of Aß across the BBB were determined by stereotaxic intra-cerebral or i.a. infusion of [(125) I]-Aß1-40 respectively. Receptor for advanced glycation end products (RAGE) and low-density lipoprotein receptor-related protein 1 (LRP1), which are involved in Aß influx and efflux, PPARγ and NF-κB p65 at the BBB, as well as hippocampal Aß, caspase-3, Bax and Bcl-2 were assayed by Western blot, immunohistochemistry and RT-PCR. In vivo, hippocampal LTP was recorded, and Morris water maze and Y-maze tasks were performed. KEY RESULTS: Treatment with PPARγ agonists, rosiglitazone (0.8 mg·kg(-1) ) and pioglitazone (9.0 mg·kg(-1) ), for 6 weeks significantly increased Aß efflux and decreased Aß influx across the BBB in db/db mice. Concomitantly, they decreased hippocampal Aß1-40 and Aß1-42 , suppressed neuronal apoptosis, as indicated by decreased caspase-3 activity and increased ratio of Bcl-2/Bax, and increased hippocampal plasticity, characterized by an enhanced in vivo LTP and better performance in behavioural tests. Furthermore, the PPARγ agonists induced the expression of LRP1 gene by activation of PPARγ and suppressed RAGE gene expression by inactivation of NF-κB signalling at the BBB of db/db mice. CONCLUSIONS AND IMPLICATIONS: PPARγ agonists modify abnormal Aß transport across the BBB and this is accompanied by amelioration of ß-amyloidosis and an improvement in hippocampal plasticity in diabetic mice.

Antidiabetic drugs restore abnormal transport of amyloid-ß across the blood-brain barrier and memory impairment in db/db mice.

Previous studies have shown significant changes in amyloid-ß (Aß) transport across the blood-brain barrier (BBB) under diabetic conditions with hypoinsulinemia, which is involved in diabetes-associated cognitive impairment. Present study employed db/db mice with hyperinsulinemia to investigate changes in Aß transport across the BBB, hippocampal synaptic plasticity, and restorative effects of antidiabetic drugs. Our results showed that db/db mice exhibited similar changes in Aß transport across the BBB to that of insulin-deficient mice. Chronic treatment of db/db mice with antidiabetic drugs such as metformin, glibenclamide and insulin glargine significantly decreased Aß influx across the BBB determined by intra-arterial infusion of (125)I-Aß(1-40), and expression of the receptor for advanced glycation end products (RAGE) participating in Aß influx. Insulin glargine, but not, metformin or glibenclamide increased Aß efflux across the BBB determined by stereotaxic intra-cerebral infusion of (125)I-Aß(1-40), and expression of the low-density lipoprotein receptor related protein 1 (LRP1) participating in Aß efflux. Moreover, treatment with these drugs significantly decreased hippocampal Aß(1-40) or Aß(1-42) and inhibited neuronal apoptosis. The drugs also ameliorated memory impairment confirmed by improved performance on behavioral tasks. However, insulin glargine or glibenclamide, but not metformin, restored hippocampal synaptic plasticity characterized by enhancing in vivo long-term potentiation (LTP). Further study found that these three drugs significantly restrained NF-κB, but only insulin glargine enhanced peroxisome proliferator-activated receptor γ (PPARγ) activity at the BBB in db/db mice. Our data indicate that the antidiabetic drugs can partially restore abnormal Aß transport across the BBB and memory impairment under diabetic context.

[The relationship between coagulation/anticoagulation imbalance and oxidative stress in patients with chronic obstructive pulmonary disease].

OBJECTIVE: To explore the relationship between coagulation/anticoagulation imbalance and oxidative stress in the patients with chronic obstructive pulmonary disease during acute exacerbation (AECOPD) before and after treatment. METHODS: Plasma tissue factor (TF) and tissue factor pathway inhibitor (TFPI) activity was detected by chromogenic assay in 28 AECOPD patients before and after treatment as well as in 30 healthy controls. The total antioxidative capacity (TAC), malondialdehyde (MDA) and glutathione peroxidase (GSH-PX) in plasma were measured in both groups. RESULTS: The levels of plasma TF and TFPI, and their ratio (TF/TFPI) in AECOPD patients before treatment were significantly higher than those after treatment (all P < 0.01), the latter were still higher than those in the healthy persons (all P < 0.01). The levels of the TAC and GSH-PX in plasma in AECOPD patients before treatment were significantly lower than those after treatment (all P < 0.01), the latter were still lower than those in the healthy persons (all P < 0.01). The plasma MDA in AECOPD patients before treatment was significantly higher than that after treatment (P < 0.01), which was still higher than that in the healthy persons (P < 0.05). There were negative correlations between TF/TFPI ratio and TAC (r = -0.518, P < 0.01), GSH-PX (r = -0.454, P < 0.05), PaO2 (r = -0.511, P < 0.01) respectively and a positive correlation between TF/TFPI ratio and the percentage of neutrophils (r = 0.379, P < 0.05) in AECOPD patients before treatment. There still were negative correlations between TF/TFPI ratio and TAC (r = -0.420, P < 0.05), FEV(1)% to predicted (r = -0.480, P < 0.05) respectively, and a positive correlation between TF/TFPI ratio and MDA (r = 0.451, P < 0.05) in AECOPD patients after treatment. CONCLUSIONS: There existed coagulation/anticoagulation imbalance and oxidation/antioxidation imbalance before and after treatment in AECOPD patients and their relationship was explored.

[Effects of rosiglitazone on peroxisome proliferator activated receptor-γ pathway in patients with chronic obstructive pulmonary disease].

OBJECTIVE: To explore the effects of rosiglitazone on peroxisome proliferator activated receptor-γ (PPAR-γ), nuclear factor-κB and tumor necrosis factor-α (TNF-α) in patients with chronic obstructive pulmonary disease (COPD). METHODS: From Apr. 2010 to Nov. 2010, 30 patients with acute exacerbations of COPD, 22 males and 8 females, age 54 - 87 (mean 72 ± 9) years and 24 healthy controls, 18 males and 6 females, age 52 - 80 (mean 69 ± 10) years were included. The peripheral blood mononuclear cells (PBMCs) were isolated from venous blood and then cultured. On the basis of the treatment given, the PBMCs of COPD patients were divided into 3 groups: non-treatment group, rosiglitazone treatment group (rosiglitazone group) and rosiglitazone and GW9662 treatment group (combined treatment group). Cells from the healthy controls (control group) did not receive any drug treatment. The mRNA expression of PPAR-γ and NF-κB was measured with real-time PCR. The protein expression and nuclear translocation of PPAR-γ and NF-κB were detected using immunofluorescence with laser scanning confocal microscopy. The TNF-α level in culture supernatant was measured with ELISA. One-way ANOVA and LSD-t test and the Pearson correlation coefficient were used for statistical analysis. RESULTS: The mRNA and protein levels of PPAR-γ were lower in the non-treatment group (0.52 ± 0.10, 55 ± 11) than those in the control group (1, 85 ± 9), while the levels of NF-κB mRNA and protein were higher in the non-treatment group (1.69 ± 0.07, 145 ± 17) than those in the control group (1, 118 ± 7). The mRNA and protein levels of PPAR-γ in the rosiglitazone group (4.47 ± 0.11, 204 ± 12) were significantly increased compared with the non-treatment group, while the mRNA and protein levels of NF-κB (0.33 ± 0.04, 59 ± 14) were remarkably decreased compared with the non-treatment group. The mRNA and protein levels of PPAR-γ (2.25 ± 0.31, 142 ± 23) were significantly decreased in the combined treatment group compared to the rosiglitazone group, but higher compared with the non-treatment group, while the mRNA and protein levels of NF-κB (0.64 ± 0.02, 90 ± 10) were increased compared with the rosiglitazone group, but decreased compared to the non-treatment group (F = 29.21 - 567.42, all P < 0.01). The TNF-α level was significantly higher in the non-treatment group (96.2 ± 1.4) µg/L than that in the control group (85.3 ± 1.0) µg/L. The TNF-α level in the rosiglitazone group (63.0 ± 2.5) µg/L was remarkably decreased compared with the non-treatment group, while that in the combined treatment group (83.3 ± 1.9) µg/L was increased compared with the rosiglitazone group, but decreased compared to the non-treatment group (F = 293.72, P < 0.01). The proteins of PPAR-γ and NF-κB were respectively located in cytoplasm and in nucleus in the non-treatment group, meanwhile they were located in both cytoplasm and nucleus in the control group. PPAR-γ protein was translocated from cytoplasm into nucleus and NF-κB protein was translocated from nucleus into cytoplasm in the rosiglitazone group. In the combined treatment group, PPAR-γ protein translocated from nucleus into cytoplasm and NF-κB protein partly translocated from cytoplasm into nucleus. By linear correlation analysis, PPAR-γ protein was negatively correlated with NF-κB protein and TNF-α level (r = -0.935, -0.924, all P < 0.01), while NF-κB protein was positively correlated to TNF-α level (r = 0.846, P < 0.01). CONCLUSIONS: The expression and activity of PPAR-γ were decreased in COPD patients. PPAR-γ agonist rosiglitazone inhibited inflammation in COPD through upregulating the expression and activity of PPAR-γ and inhibition of NF-κB and TNF-α. It suggests that PPAR-γ may play an important role in the inflammation of COPD.