Interaction between Saikosaponin D, Paeoniflorin, and Human Serum Albumin.

Saikosaponin D (SSD) and paeoniflorin (PF) are the major active constituents of Bupleuri Radix and Paeonia lactiflora Pall, respectively, and have been widely used in China to treat liver and other diseases for many centuries. We explored the binding of SSD/PF to human serum albumin (HSA) by using fluorospectrophotometry, circular dichroism (CD) and molecular docking. Both SSD and PF produced a conformational change in HSA. Fluorescence quenching was accompanied by a blue shift in the fluorescence spectra. Co-binding of PF and SSD also induced quenching and a conformational change in HSA. The Stern-Volmer equation showed that quenching was dominated by static quenching. The binding constant for ternary interaction was below that for binary interaction. Site-competitive experiments demonstrated that SSD/PF bound to site I (subdomain IIA) and site II (subdomain IIIA) in HSA. Analysis of thermodynamic parameters indicated that hydrogen bonding and van der Waals forces were mostly responsible for the binary association. Also, there was energy transfer upon binary interaction. Molecular docking supported the experimental findings in conformation, binding sites and binding forces.

Ethyl Acetate Extract from Celastrus aculeatus Merr. Suppresses Synovial Inflammation in Adjuvant Arthritis Rats through Apoptosis Induction of CD4(+)CD25(+)FOXP3(+) T Cells.

Celastrus aculeatus Merr. has been widely used in traditional Chinese medicine to treat rheumatoid arthritis (RA) in clinic. However, the main active fraction of this plant is still unclear. In this study, we attempted to evaluate the suppressive effect of ethyl acetate extract (EAE) from Celastrus aculeatus Merr. on synovial inflammation in adjuvant arthritis (AA) rats induced by Mycobacterium tuberculosis H37Ra (Mtb) and to explore the underlying mechanisms. SD rats immunized with heat-killed Mtb were fed with EAE and observed for erythema, swelling, and induration of each paw. The pathologic changes in joint synovium were tested by hematoxylin-eosin staining. Apoptosis induction of synoviocytes was tested immunohistochemically. Apoptosis of peripheral lymphocytes and the level of regulatory T cells were analyzed by flow cytometry. After treatment with EAE, the joint inflammation in rats with AA was alleviated. Both apoptotic ratios of synoviocytes and peripheral lymphocytes and the ratio of CD4(+)CD25(+)FOXP3(+) to CD4 regulatory T cells were significantly increased. In summary, we first demonstrated that EAE of Celastrus aculeatus Merr. can inhibit synovial inflammation in AA rats through apoptosis induction of CD4(+)CD25(+)FOXP3(+) T cells. Our study provides a rationale for the application of Celastrus aculeatus Merr. to treat RA.

[Study on the activated fraction with proliferation and apoptosis effect on T lymphocyte of Celastrus aculeatus].

OBJECTIVE: To screen the activated fraction from Celastrus aculeatus and study its effect on T lymphocyte apoptosis. METHODS: Different polarity fractions were isolated from Celastrus aculeatus extract. Flow Cytometry method was used to detect apoptosis ratio of the active fractions. RESULTS: Different fractions extract from Celastrus aculeatus and GSF-A could significantly inhibit T lymphocyte proliferation and induce T lymphocyte apoptosis. CONCLUSION: The activated fractions isolated from Celastrus aculeatus have anti-inflammatory effect. Its mechanism may be related to the apoptosis effect on T lymphocyte.

Heat shock protein 72 is associated with the hepatitis C virus replicase complex and enhances viral RNA replication.

The NS5A protein of the hepatitis C virus (HCV) is an integral component of the viral replicase. It also modulates cellular signaling and perturbs host interferon responses. The multifunctional characteristics of NS5A are mostly attributed to its ability to interact with various cellular proteins. This study aimed to identify the novel cellular factors that interact with NS5A and decipher the significance of this interaction in viral replication. The NS5A-interacting proteins were purified by the tandem affinity purification (TAP) procedure from cells expressing NS5A and identified by mass spectrometry. The chaperone protein Hsp72 was identified herein. In vivo protein-protein interaction was verified by co-immunoprecipitation and an in situ proximity ligation assay. In addition to NS5A, Hsp72 was also associated with other members of the replicase complex, NS3 and NS5B, suggesting that it might be directly involved in the HCV replication complex. Hsp72 plays a positive regulatory role in HCV RNA replication by increasing levels of the replicase complex, which was attributed either to the increased stability of the viral proteins in the replicase complex or to the enhanced translational activity of the internal ribosome entry site of HCV. The fact that the host chaperone protein Hsp72 is involved in HCV RNA replication may represent a therapeutic target for controlling virus production.

[Influence of Qingxiang San on substance P, somatostatin in rats model with the spleen and stomach wet heat syndrome].

OBJECTIVE: To observe the influence of Qingxiang San (QS) on substance P (SP), somatostatin (SS) in rats model of spleen and stomach wet heat syndrome. METHODS: 24 rats were divided into 3 groups (each group 8 rats) randomly: the normal control group (NCG), wet heat group (WHG), QS group (QSG). We set up the spleen and stomach wet heat syndrome of rats model by the composite factors such as greasy and sweet food, wet and hot environment, pathogen and so on. Then the contents of SP, SS were detected by radioimmuno assay. RESULTS: The content of SP, SS in WHG were obviously lower than NCG (P<0.01); QSG compared with WHG, the content of SP, SS increased (P<0.01); The content of SP obviously increased when QSG compared with NCG (P<0.01); About the content of SS, there was no significant difference between QSG and NCG (P>0.05), illustrating that QS can increase the content of SP, SS which had decreased. CONCLUSION: QS can regulate the content of SP and SS and increase them which had decreased.

Nuclear receptor interaction protein, a coactivator of androgen receptors (AR), is regulated by AR and Sp1 to feed forward and activate its own gene expression through AR protein stability.

Previously, we found a novel gene, nuclear receptor interaction protein (NRIP), a transcription cofactor that can enhance an AR-driven PSA promoter activity in a ligand-dependent manner in prostate cancer cells. Here, we investigated NRIP regulation. We cloned a 413-bp fragment from the transcription initiation site of the NRIP gene that had strong promoter activity, was TATA-less and GC-rich, and, based on DNA sequences, contained one androgen response element (ARE) and three Sp1-binding sites (Sp1-1, Sp1-2, Sp1-3). Transient promoter luciferase assays, chromatin immunoprecipitation and small RNA interference analyses mapped ARE and Sp1-2-binding sites involved in NRIP promoter activation, implying that NRIP is a target gene for AR or Sp1. AR associates with the NRIP promoter through ARE and indirectly through Sp1-binding site via AR-Sp1 complex formation. Thus both ARE and Sp1-binding site within the NRIP promoter can respond to androgen induction. More intriguingly, NRIP plays a feed-forward role enhancing AR-driven NRIP promoter activity via NRIP forming a complex with AR to protect AR protein from proteasome degradation. This is the first demonstration that NRIP is a novel AR-target gene and that NRIP expression feeds forward and activates its own expression through AR protein stability.

[Apoptosis-inducing and anti-proliferation effect of interferon-alpha on U937 cells and its mechanism].

This study was aimed to investigate the anti-proliferation effect of interferon-alpha (IFN-alpha) on leukemic U937 cells and its mechanism. The U937 cells were given with various concentrations of IFN-alpha (500, 1 000, 2,000, 3,000 and 4,000 U/L) and at different time (0, 12, 24, 36, 48 hours), the inhibitory ratio was measured by MTT assay, apoptosis rate was detected by flow cytometry (FCM), the expression of cell cycle-associated cyclin E mRNA was measured by RT-PCR. The results showed that IFN-alpha (2,000 U/L) could cause apoptosis, after being treated by various concentrations of IFN-alpha, the growth of U937 cells was inhibited significantly, the apoptosis rate was 25.82% - 70.54% (P < 0.01), the cycle-associated cyclin E mRNA expression decreased, the growth of U937 cells was significantly inhibited, the suppression of U937 by IFN-alpha was both in time-and dose-dependent manner. It is concluded that IFN-alpha has apparent anti-proliferation and apoptosis-inducing effects on U937 cells. These results will provide strong laboratory evidence for IFN-alpha clinical application in leukemia therapy.