Comparison of catalytic functions and expression patterns of two pinene synthases from Wurfbainia villosa / 中国中药杂志

Wurfbainia villosa fruit is rich in volatile terpenoids, among which pinene is one of the main components and has anti-inflammatory, antibacterial, anti-tumor, and other pharmacological activities. This research group found that W. villosa fruits were rich in α-pinene by GC-MS, and terpene synthase(WvTPS63, formerly known as AvTPS1) with β-pinene as the main product was cloned and identified, but α-pinene synthase had not been identified. In this study, based on the genome data of W. villosa, we screened and found WvTPS66 with highly similar sequences to WvTPS63, identified enzyme functions of WvTPS66 in vitro, and performed a comparative analysis of sequence, catalytic function, expression pattern, and promoter with WvTPS63. Multiple sequence alignment showed that the amino acid sequences of WvTPS63 and WvTPS66 were highly similar and the conservative motif of terpene synthase was almost identical. In vitro enzymatic experiments on catalytic functions showed that both could produce pinene, and the main product of WvTPS63 was β-pinene, while that of WvTPS66 was α-pinene. Expression pattern analysis showed that WvTS63 was highly expressed in flowers, WvTPS66 was expressed in the whole plant, and the highest expression level was found in the pericarp, which indicated that it might be mainly responsible for the synthesis of α-pinene in fruits. In addition, promoter analysis revealed the presence of multiple regulatory elements related to stress response in the promoter regions of both genes. The findings of this study can provide a reference for the functional study of terpene synthase genes and new genetic elements for pinene biosynthesis.

Long-term interleukin 10 therapy in chronic hepatitis C patients has a proviral and anti-inflammatory effect.

An imbalance in Th1 and Th2 cytokine production is implicated in disease progression of HCV. Our aim was to determine the effect of IL-10 administration in patients with HCV-related liver disease. Thirty patients with advanced fibrosis who had failed antiviral therapy were enrolled in a 12-month treatment regimen with SQ IL-10 given daily or thrice weekly. Liver biopsies were performed before and after therapy. Serum and PBMC were collected for HCV RNA, ALT, and functional T-cell analysis. IL-10 led to significant improvement in serum ALT (mean ALT: day 0 = 142 +/- 17 vs. month 12 = 75 +/- 10; P <.05). Hepatic inflammation score decreased by at least 2 in 13 of 28 patients (mean decrease from 4.6 +/- 0.3 to 3.7 +/- 0.3, P <.05) and 11 of 28 showed a reduction in fibrosis score (mean change from 5.0 +/- 0.2 to 4.5 +/- 0.3, P <.05). Serum HCV RNA levels increased by 0.5 log during therapy (mean HCV RNA day 0: 12.3 +/- 3.0 Meq/mL; 12 months: 38 Meq/mL; P <.05) and returned to baseline at the end of follow-up (11.0 +/- 2.4 Meq/mL). Five patients developed viral loads of greater than 120 Meq/mL and two of these developed an acute flare in serum ALT. IL-10 caused a decrease in the number of HCV-specific CD4+ and CD8+ IFN-gamma secreting T cells and alterations in PBMC cytokine production towards a Th2 dominant profile. These changes parallel the improvement in ALT and rise in HCV RNA. In conclusion, long-term rIL-10 therapy appears to decrease disease activity, but also leads to increased HCV viral burden via alterations in immunologic viral surveillance.

CD8+ T-cell interaction with HCV replicon cells: evidence for both cytokine- and cell-mediated antiviral activity.

The interaction between the host immune response and infected hepatocytes plays a central role in the pathogenesis of hepatitis C virus (HCV). The lack of a suitable animal or in vitro model has hindered our understanding of the host T-cell/HCV interaction. Our aim was to develop an in vitro model to study the mechanisms of HCV-specific T-cell-mediated antiviral and cytolytic function. The HCV replicon was HLA typed and lymphocytes were obtained from an HLA class I-matched subject. CD8(+) T cells were expanded with 2 HCV-specific/HLA-restricted peptides for NS3. Lymphocyte preparations were cocultured with HCV replicon (FCA1) and control (Huh7) cells labeled with (51)Cr. After a 48-hour incubation, the cells were harvested for RNA extraction. Standard blocking assays were performed in the presence of anti-interferon gamma (IFN-gamma), anti-tumor necrosis factor alpha (TNF-alpha), and anti-FasL. Cytolytic activity was measured by (51)Cr release. HCV replicon cells express homozygous HLA-A11 alleles and present HCV nonstructural proteins. HCV-specific expansion of CD8(+) cells led to a 10-fold decrease in HCV replication by Northern blot analysis and 21% specific lysis of FCA1 cells (compared with 2% of control Huh7 cells). Twenty percent of this antiviral activity was independent of T-cell binding, suggesting cytokine-mediated antiviral activity. The CD8(+) antiviral effect was markedly reduced by blocking either IFN-gamma or FasL but was unaffected by blocking TNF-alpha. In conclusion, HCV-specific CD8(+) cells inhibit viral RNA replication by cytokine-mediated and direct cytolytic effects. This T-cell/HCV subgenomic replicon system represents a model for the investigation of CD8 cell interaction with HCV-infected hepatocytes.