Biosynthesis of polyketides by two type III polyketide synthases from Aloe barbadensis.

Various bioactive polyketides have been found in Aloe barbadensis. However, the polyketide synthases (PKSs), which participate in biosynthesis of polyketides in A. barbadensis remain unknown. In this study, two type III PKSs (AbPKS1 and AbPKS2) were identified from A. barbadensis. AbPKS1 and AbPKS2 were able to utilize malonyl-CoA to yield heptaketides (TW93a and aloesone) and octaketides (SEK4 and SEK4b), respectively. AbPKS1 also exhibited catalytic promiscuity in recognizing CoA thioesters of aromatics to produce unusual polyketides. What Is more, a whole cell biocatalysis system with the capability of producing 26.4 mg/L of SEK4/SEK4b and 2.1 mg/L of aloesone was successfully established.

The protective effects of chronic intermittent hypobaric hypoxia pretreatment against collagen-induced arthritis in rats.

OBJECTIVE: To explore the immunological mechanisms underlying the effect of chronic intermittent hypobaric hypoxia (CIHH) pretreatment on collagen-induced arthritis (CIA) in rat. METHODS: Fifty-four adult male Sprague-Dawley rats were used in the experiment. Arthritis in CIA rats (n=18) was induced by injection of collagen. The CIHH+CIA rats (n=18) were treated with CIHH (simulated 3000 m altitude, 5 hours per day for 28 days, PO2=108.8 mmHg) before CIA. The control rats (n=18) were not given any treatment. RESULTS: (1) Incidence rate of CIA in CIHH+CIA rats was significantly lower than that in CIA rats (P<0.05). (2) The paw thickness and arthritis index (AI) value in CIHH+CIA rats were lower than those in CIA rats (P<0.05). (3) The hyperplasia with inflammatory infiltration in synovial tissue of joints in CIHH+CIA rats was much alleviative compared with CIA rats. (4) TNF-α, IFN-γ, IL-4 and IL-17 in synovial tissue of joint and serum in CIHH+CIA rats were decreased compared with CIA rats (P<0.05). (5) The number of CD4-positive T-lymphocytes and the ratio of CD4/CD8 T-lymphocytes in peripheral blood in CIHH+CIA rats were lower than those in CIA rats (P<0.05). (6) The protein expression of HIF-1α and NF-κB in synovial tissue of joint in CIHH+CIA rats was decreased compared with CIA rats (P<0.05). CONCLUSION: CIHH pretreatment has a protective effect against collagen-induced arthritis in rat through down-regulation of HIF-1α and NF-κB, inhibition of inflammatory cytokines TNF-α and IL-17, and balance in CD4/CD8 and Th1/Th2 T lymphocytes.

Protective effect of n-butanol extract from Alpinia oxyphylla on learning and memory impairments.

Alzheimer's disease (AD) is one of the major neurological diseases of the elderly. How to safely and effectively remove the toxic Aß42 peptide through blood-brain barrier (BBB) is considered to be an effective method for the prevention and treatment of AD. The compounds whose molecule weight is less than 400 Da and the number of hydrogen bonding is less than 10 are more likely to permeate BBB. In our previous study, we have several small molecule compounds which are isolated from n-butanol (NB) extract of Alpinia oxyphylla that are similar with this kind of compounds This study explored the neuroprotective effects of the NB significantly protected against learning and memory impairments induced by Aß(1-42) in Y-maze test, active avoidance test and Morris water maze test. Besides, NB (180 mg/kg, 360 mg/kg) was able to attenuate the neuronal damage and apoptosis in the frontal cortex and hippocampus in mice. In addition, the inhibition of ß-secretase and the level of Aß(1-42) are also involved in the action mechanisms of NB in this experimental model. This study provided an experimental basis for clinical application of A. oxyphylla Miq. in AD therapy.

Comparison of Tripterygium wilfordii Hook F with methotrexate in the treatment of active rheumatoid arthritis (TRIFRA): a randomised, controlled clinical trial.

OBJECTIVES: To compare the efficacy and safety of Tripterygium wilfordii Hook F (TwHF) with methotrexate (MTX) in the treatment of active rheumatoid arthritis (RA). METHODS: Design: a multicentre, open-label, randomised controlled trial. All patients were assessed by trained investigators who were unaware of the therapeutic regimen. INTERVENTION: 207 patients with active RA were randomly allocated (1:1:1) to treatment with MTX 12.5 mg once a week, or TwHF 20 mg three times a day, or the two in combination. At week 12, if reduction of the 28-joint count Disease Activity Score (DAS28) was <30% in the monotherapy groups, the patient was switched to MTX+TwHF. The primary efficacy point was the proportion of patients achieving an American College of Rheumatology (ACR) 50 response at week 24. RESULTS: 174/207 (84.1%) patients completed 24 weeks of the trial. In an intention-to-treat analysis, the proportion of patients reaching the ACR50 response criteria was 46.4% (32/69), 55.1% (38/69) and 76.8% (53/69), respectively, in the MTX, TwHF and MTX+TwHF groups (TwHF vs MTX monotherapy, p=0.014; MTX+TwHF vs MTX monotherapy, p<0.001). Similar statistically significant patterns at week 24 were found for ACR20, ACR70, clinical Disease Activity Index good responses, EULAR good response, remission rate and low disease activity rate. Significant improvement in the Health Assessment Questionnaire and 36-item Short-Form Health Survey questionnaire scores from baseline to week 24 was seen in each treatment arm (p<0.05), though no significant difference was found among the treatment arms (p>0.05). The result of per-protocol analysis agreed with that seen in the intention-to-treat analysis. Seven, three and five women in the TwHF, MTX and combination groups, respectively, developed irregular menstruation (TwHF vs MTX monotherapy, p=0.216). CONCLUSIONS: TwHF monotherapy was not inferior to, and MTX+TwHF was better than, MTX monotherapy in controlling disease activity in patients with active RA. TRIAL REGISTRATION NUMBER: NCT01613079.

The effects of sesquiterpenes-rich extract of Alpinia oxyphylla Miq. on amyloid-ß-induced cognitive impairment and neuronal abnormalities in the cortex and hippocampus of mice.

As a kind of medicine which can also be used as food, Alpinia oxyphylla Miq. has a long clinical history in China. A variety of studies demonstrated the significant neuroprotective activity effects of chloroform (CF) extract from the fruits of Alpinia oxyphylla. In order to further elucidate the possible mechanisms of CF extract which mainly contains sesquiterpenes with neuroprotection on the cognitive ability, mice were injected with Aß(1-42) and later with CF in this study. The results showed that the long-term treatment of CF enhanced the cognitive performances in behavior tests, increased activities of glutathione peroxidase (GSH-px) and decreased the level of malondialdehyde (MDA), acetylcholinesterase (AChE), and amyloid-ß (Aß), and reversed the activation of microglia, degeneration of neuronal acidophilia, and nuclear condensation in the cortex and hippocampus. These results demonstrate that CF ameliorates learning and memory deficits by attenuating oxidative stress and regulating the activation of microglia and degeneration of neuronal acidophilia to reinforce cholinergic functions.

Jujuboside A, a neuroprotective agent from semen Ziziphi Spinosae ameliorates behavioral disorders of the dementia mouse model induced by Aß 1-42.

Semen Ziziphi Spinosae (SZS) has been used as a hypnotic-sedative medicine for thousands of years. Recently, SZS has also shown notable neuroprotective activities via anti-oxidative and anti-inflammatory effects in dementia animals. Jujuboside A (JuA), isolated from SZS, has been proved to be a major hypnotic-sedative component of SZS. In the present study, we firstly evaluated the effects of intracerebroventricular (ICV) injection of JuA (0.02 and 0.2mg/kg) for five consecutive days on cognitive impairment induced by ICV injection of Aß 1-42. The results showed that ICV treatment with JuA significantly mitigated learning and memory impairment in mice induced by Aß 1-42 as measured by the Y-maze, active avoidance and Morris water maze. Furthermore, ICV treatment with JuA reduced the level of Aß 1-42 in hippocampus, significantly inhibited the activities of acetylcholinesterase (AChE) and NO, and decreased the amount of the increased malondialdehyde (MDA) in the hippocampus and cerebral cortex of mice treated with ICV injection of Aß 1-42. Shrinkage of nuclei, swollen and eccentrically dispersed neuronal bodies were observed in hippocampus of AD mice induced by Aß 1-42, however, JuA noticeably improved the histopathological damage. Cumulatively, the present study indicates that JuA may serve as a potential therapeutic agent for the treatment of Alzheimer' disease.

[Effect of selective phosphodiesterase 4 inhibitors on nuclear factor kappa B, tumor necrosis factor-α and interleukin-8 expression in peripheral blood mononuclear cells in rheumatoid arthritis with interstitial lung disease].

OBJECTIVE: To investigate the effect of selective phosphodiesterase (PDE) 4 inhibitors on nuclear factor kappa B (NF-κB), tumor necrosis factor-α (TNFα) and interleukin-8 (IL-8) secreted by peripheral blood mononuclear cells (PBMCs) in patients diagnosed as rheumatoid arthritis with interstitial lung disease (RA-ILD). METHODS: PBMCs isolated from 15 healthy volunteers (group A) and 20 patients with untreated active RA-ILD (group B) were cultured in vitro. PBMCs from healthy subjects were considered as normal control. PBMCs from RA-ILD patients were divided into four groups with different treatment: blank group (B1), theophylline group (B2), selective PDE4 inhibitor rolipram group (B3), and glucocorticoid group (B4) with dexamethasone. The expression of NF-κB was determined by immunocytochemical staining, and the levels of TNFα and IL-8 in the culture supernatant were detected by enzyme linked immunosorbent assay (ELISA). RESULTS: (1) The activity of NF-κB and the levels of TNFα and IL-8 in group B1 were significant higher than that in group A (P < 0.01). Compared with group B1, three parameters above were similar to those in group B2 (P > 0.05), while group B3 and group B4 had significant decreased levels of three parameters (P < 0.01); IL-8 level in group B4 was significantly lower than that in group B3 (P < 0.05). (2) TNFα and IL-8 levels were positively correlated with NF-κB activity in group B (r = 0.902 and 0.735, P < 0.01 respectively). (3) The reduction of TNFα and IL-8 levels were positively correlated with reduction of NF-κB activity after intervention of rolipram in group B3 (r = 0.874, P < 0.01; r = 0.561, P < 0.05 respectively). CONCLUSION: NF-κB activation and proinflammatory cytokines were involved in the pathogenesis of RA-ILD. selective PDE4 inhibitors may inhibit the production of inflammatory cytokines by inhibiting the activity of the transcription factor NF-κB in PBMC, thus inhibiting the inflammatory reaction of RA-ILD.

Protection of chronic intermittent hypobaric hypoxia against collagen-induced arthritis in rat through increasing apoptosis.

The aim of present study was to investigate the effect of chronic intermittent hypobaric hypoxia (CIHH) on collagen-induced arthritis (CIA) in rat. Fifty male adult Sprague-Dawley rats were randomly divided into 5 groups: CIHH pre-treatment group (Pre-T), pre-control group (Pre-C), CIHH post-treatment group (Post-T), post-control group (Post-C) and blank control group (Con). The rats in Pre-T and Post-T groups were exposed to 28 d of hypobaric hypoxia (simulated 3 000 m altitude, 5 h per day, pO2 = 108.8 mmHg, 14% O2) in a hypobaric chamber before and 12 days after CIA induction, respectively. The rats in Pre-C and Post-C groups were only experienced CIA induction, being control groups for Pre-T and Post-T groups, respectively. The rats in Con group were not given any treatment. The thickness of two-hind paw of rat was measured with spiral micrometer and the degree of arthritis was evaluated by arthritis index (AI). Morphological changes of ankle joint were observed through HE staining. The apoptotic rate in synovial tissue was measured by terminal dUTP nick end labeling (TUNEL) and the apoptotic rate of CD3(+) T lymphocyte in spleen was measured by flow cytometry technique. The protein expressions of Bcl-2 and Bax were measured using immunohistochemistry SP method. The results showed that incidence rate of CIA in Pre-T rats was lower than that in Pre-C rats (P < 0.05). AI in Pre-T and Post-T rats were smaller than those in Pre-C and Post-C, respectively (P < 0.05). In Pre-C and Post-C rats, there were hyperplasia of synovial cell, pannus forming, infiltration with inflammatory cell, and destroyed cartilage and bone in ankle joint. On the contrary, pathological changes of ankle joint were alleviated significantly in Pre-T and Post-T rats. Compared with Pre-C and Post-C rats, apoptotic rates of synovial cell and T lymphocyte in Pre-T and Post-T rats were increased (P < 0.05). As to the possible anti-apoptosis mechanism, CIHH, no matter before and after CIA induction, decreased Bcl-2 expression and increased Bax expression in joint synovial cells and spleen T lymphocytes (P < 0.05), respectively. In conclusion, CIHH possesses a protective effect against CIA in rat by enhancing apoptosis of synovial cells and T lymphocytes, which may be related to the inhibition of Bcl-2 protein expression and the promotion of Bax protein expression.

[Influence of exogenous RNA upon expression of mouse albumin gene and its sensitivity to DNase I].

Cultured mouse fibroblasts were treated with rabbit liver RNA. Rat liver RNA was injected into mouse prostates. Influence of exogenous RNA upon expression of mouse albumin gene was detected by immunohistochemical staining. Nucleuses of cultured mouse fibroblasts treated with different RNAs were isolated and digested with DNase I. Mouse albumin gene was amplified by PCR to detect levels of its digestion. It was found that exogenous RNAs could increase the sensitivity of mouse albumin gene to DNase I digestion and promote its expression.