Reprogramming of arachidonic acid metabolism using α-terpineol to alleviate asthma: insights from metabolomics.

Asthma is a chronic inflammatory disorder in airways with typical pathologic features of airway inflammation and mucus hypersecretion. α-Terpineol is a monocyclic terpene found in many natural plants and foods. It has been reported to possess a wide range of pharmacological activities including anti-inflammatory and expectorant effects. However, the role of α-terpineol in asthma and its potential protective mechanism have not been well elucidated. This study is designed to investigate the pharmacological effect and mechanism of α-terpineol on asthmatic mice using the metabolomics platform. A murine model of asthma was established using ovalbumin (OVA) sensitization and then challenged for one week. The leukocyte count and inflammatory cytokines in the bronchoalveolar lavage fluid (BALF), lung histopathology, inflammatory  infiltrate and mucus secretion were evaluated. An ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS)-based metabolomics study was performed on lung tissues and serum to explore endogenous small molecule metabolites affected by α-terpineol in asthmatic mice. After α-terpineol treatment, leukocyte count, inflammatory cytokines in the BALF, and peribronchial inflammation infiltration were significantly downregulated. Goblet cell hyperplasia and mucus secretion were attenuated, with the level of Muc5ac in BALF decreased. These results proved the protective effect of α-terpineol against airway inflammation, mucus hypersecretion and Th1/Th2 immune imbalance. To further investigate the underlying mechanisms of α-terpineol in asthma treatment, UPLC-MS/MS-based metabolomics analysis was performed. 26 and 15 identified significant differential metabolites were found in the lung tissues and serum of the control, model and α-terpineol groups, respectively. Based on the above differential metabolites, enrichment analysis showed that arachidonic acid (AA) metabolism was reprogrammed in both mouse lung tissues and serum. 5-Lipoxygenase (5-LOX) and cysteinyl leukotrienes (CysLTs) are the key enzyme and the end product of AA metabolism, respectively. In-depth studies have shown that pretreatment with α-terpineol can alleviate asthma by decreasing the AA level, downregulating the expression of 5-LOX and reducing the accumulation of CysLTs in mouse lung tissues. In summary, this study demonstrates that α-terpineol is a potential agent that can prevent asthma via regulating disordered AA metabolism.

Insight gained via ultra-performance liquid chromatography tandem mass spectrometry-based metabolomics: Protective effect of Artemisia argyi H.Lév. & Vaniot essential oil on lipopolysaccharide-induced liver injury mice.

Artemisia argyi H.Lév. & Vaniot essential oil (AAEO) has shown pharmacological effects such as anti-inflammation, antioxidant, and anti-tumor properties. However, the protective effect of AAEO on lipopolysaccharide (LPS)-induced liver injury and its potential protective mechanism are still unclear. In this study, we used ultra-performance liquid chromatography tandem mass spectrometry metabolomics techniques to investigate the changes in liver tissue metabolites in mice exposed to LPS with or without AAEO treatment for 14 days. The biochemical results showed that compared with the control group, AAEO significantly reduced the levels of liver functional enzymes, suggesting a significant improvement in liver injury. In addition, the 18 differential metabolites identified by metabolomics were mainly involved in the reprogramming of arachidonic acid metabolism, tryptophan metabolism, and purine metabolism. AAEO could significantly inhibit the expression of COX-2, IDO1, and NF-κB; enhance the body's anti-inflammatory ability; and alleviate liver injury. In summary, our study identified the protective mechanism of AAEO on LPS-induced liver injury at the level of small molecular metabolites, providing a potential liver protective agent for the treatment of LPS-induced liver injury.

HIV-1 Tat enhances purinergic P2Y4 receptor signaling to mediate inflammatory cytokine production and neuronal damage via PI3K/Akt and ERK MAPK pathways.

BACKGROUND: HIV-associated neurocognitive disorders (HANDs) afflict more than half of HIV-1-positive individuals. The transactivator of transcription (Tat) produced by HIV virus elicits inflammatory process and is a major neurotoxic mediator that induce neuron damage during HAND pathogenesis. Activated astrocytes are important cells involved in neuroinflammation and neuronal damage. Purinergic receptors expressed in astrocytes participate in a positive feedback loop in virus-induced neurotoxicity. Here, we investigated that whether P2Y4R, a P2Y receptor subtype, that expressed in astrocyte participates in Tat-induced neuronal death in vitro and in vivo. METHODS: Soluble Tat protein was performed to determine the expression of P2Y4R and proinflammatory cytokines in astrocytes using siRNA technique via real-time PCR, Western blot, and immunofluorescence assays. Cytometric bead array was used to measure proinflammatory cytokine release. The TUNEL staining and MTT cell viability assay were analyzed for HT22 cell apoptosis and viability, and the ApopTag® peroxidase in situ apoptosis detection kit and cresyl violet staining for apoptosis and death of hippocampal neuron in vivo. RESULTS: We found that Tat challenge increased the expression of P2Y4R in astrocytes. P2Y4R signaling in astrocytes was involved in Tat-induced inflammatory cytokine production via PI3K/Akt- and ERK1/2-dependent pathways. Knockdown of P2Y4R expression significantly reduced inflammatory cytokine production and relieved Tat-mediated neuronal apoptosis in vitro. Furthermore, in vivo challenged with Tat, P2Y4R knockdown mice showed decreased inflammation and neuronal damage, especially in hippocampal CA1 region. CONCLUSIONS: Our data provide novel insights into astrocyte-mediated neuron damage during HIV-1 infection and suggest a potential therapeutic target for HANDs.

HIV-1 Nef-induced lncRNA AK006025 regulates CXCL9/10/11 cluster gene expression in astrocytes through interaction with CBP/P300.

BACKGROUND: HIV-associated neurocognitive disorder (HAND) is a neurodegenerative disease associated with persistent neuroinflammation and subsequent neuron damage. Pro-inflammatory factors and neurotoxins from activated astrocytes by HIV-1 itself and its encoded proteins, including the negative factor (Nef), are involved in the pathogenesis of HAND. This study was designed to find potential lncRNAs that regulate astrocyte functions and inflammation process. METHODS: We performed microarray analysis of lncRNAs from primary mouse astrocytes treated with Nef protein. Top ten lncRNAs were validated through real-time PCR analysis. Gene ontology (GO) and KEGG pathway analysis were applied to explore the potential functions of lncRNAs. RIP and ChIP assays were performed to demonstrate the mechanism of lncRNA regulating gene expression. RESULTS: There were 638 co-upregulated lncRNAs and 372 co-downregulated lncRNAs in primary astrocytes treated with Nef protein for both 6 h and 12 h. GO and KEGG pathway analysis showed that the biological functions of top differential-expressed mRNAs were associated with inflammatory cytokines and chemokine. Knockdown of lncRNA AK006025, not AK138360, inhibited significantly CXCL9, CXCL10 (IP-10), and CXCL11 expression in astrocytes treated with Nef protein. Mechanism study showed that AK006025 associated with CBP/P300 was enriched in the promoter of CXCL9, CXCL10, and CXCL11 genes. CONCLUSIONS: Our findings uncovered the expression profiles of lncRNAs and mRNAs in vitro, which might help to understand the pathways that regulate astrocyte activation during the process of HAND.

Enhancement of radiation effects by combined docetaxel and flavopiridol treatment in lung cancer cells.

BACKGROUND AND PURPOSE: To evaluate the potential role and mechanism of docetaxel plus flavopiridol in modulating radiosensitivity in vitro and in vivo. PATIENTS AND METHODS: In vitro. H460 human lung carcinoma cells were treated with docetaxel (10 nM for 1 h, at t = 0 h) --> radiation (0-5 Gy, at t = 6 h) --> flavopiridol (120 nM for 24 h, at t = 8 h). Colony forming ability was measured to assess the modulation of sensitivity. Cell cycle redistribution was measured by flow cytometric analysis using propidium iodide. Percent apoptosis was also measured by flow cytometric analysis using 7-amino-actinomycin D staining. In vivo. H460 cell xenografts were used in nude mice. Tumors were grown subcutaneously on the flank, then treated with docetaxel (2.5 mg/kg, at t = 0 h) --> radiation (2 Gy, at t = 6 h) --> flavopiridol (1.25 mg/kg, at t = 8 h) for 5 consecutive days. Tumor growth delay was then measured and compared with the control group. RESULTS: Docetaxel plus flavopiridol enhanced the effect of radiation. The maximum radiopotentiation and apoptosis were observed when the cells were treated with the sequence of docetaxel-->radiation-->flavopiridol both in vitro and in vivo. Flavopiridol and docetaxel induced G1 and G2/M arrest, respectively. CONCLUSIONS: This study shows that docetaxel plus flavopiridol enhances the effects of radiation in vitro and in vivo. Our data suggest that the mechanism of radiopotentiation by combining flavopiridol and docetaxel involves an enhancement of apoptosis and changes of cell cycle by docetaxel and flavopiridol.

Potential radiation-sensitizing effect of semisynthetic epothilone B in human lung cancer cells.

BACKGROUND AND PURPOSE: To evaluate a semisynthetic epothilone B, BMS-247550, as a potential radiosensitizer in vitro and in vivo. MATERIALS AND METHODS: Human NCI-H460 lung cancer cells were treated with either BMS-247550 or paclitaxel and in combination with radiation at multiple doses for different time periods. Surviving fractions were then analyzed using a clonogenic assay. Cell cycle redistribution by BMS-247550 was measured with propidium iodide and flow cytometry. Percent apoptosis was also measured using 7-amino-actinomycin D staining with flow cytometry. For in vivo studies, the H460 xenograft model was used in athymic nude mice. Tumors were treated with BMS-247550 (5 mg/kg) i.p. injection on days 0, 2, and 4 and/or radiation (2 Gy/day, days 0-4). RESULTS: The in vitro radiation dose enhancement ratios (DER) of 1-h BMS-247550 and paclitaxel were 2.03 and 1.34, respectively. Treatment with BMS-247550 enhanced the G2/M block and induced apoptosis; whereas in combination with radiation, the induction of apoptosis was additive. BMS-247550 in combination with radiation in vivo enhanced the tumor growth delay when compared with either drug or radiation alone. CONCLUSIONS: These results demonstrated that BMS-247550 could enhance the effects of radiation in human lung cancer cells both in vitro and in vivo and that a G2/M block and increased apoptosis might be possible explanations for the enhancement.

Radiation enhancement by the combined use of topoisomerase I inhibitors, RFS-2000 or CPT-11, and topoisomerase II inhibitor etoposide in human lung cancer cells.

BACKGROUND AND PURPOSE: We have tested the camptothecin analogs, RFS-2000 or CPT-11, in combination with both etoposide and ionizing radiation in vitro to examine the radiation enhancing potential of topoisomerase I plus topoisomerase II (Topo I+Topo II) inhibition in human cancer cells. MATERIALS AND METHODS: H460 human lung carcinoma cells were plated and treated with 10nM RFS-2000 or 4.5microM CPT-11 for 4h. Cells were then irradiated with various doses and treated with 1microM etoposide for 1.5h. Cell survival and sublethal damage recovery (SLDR) were determined by clonogenic assay. 7-aminoactinomycin D (7-AAD) staining and flow cytometry were used to analyze cell viability/apoptosis after combined treatment of drugs with radiation. RESULTS: Survival experiments showed radiation dose enhancement ratios (DER) of 1.26, 1.34, and 1.63 for RFS-2000, etoposide, and RFS-2000 plus etoposide, respectively; the corresponding DER values were 1.30, 1.39, and 1.65 for CPT-11, etoposide, and CPT-11 plus etoposide. The analysis of cell viability/apoptosis using 7-AAD staining and flow cytometry showed an additive effect. Greater inhibition of SLDR was observed with RFS-2000 plus etoposide than with either agent separately, but CPT-11 plus etoposide showed a more modest effect upon SLDR. CONCLUSIONS: These data show that the combination of Topo I inhibitors, RFS-2000 or CPT-11 plus Topo II inhibitor etoposide, is a more effective radiation enhancer than either agent alone in human lung cancer cells. The mechanism of radiation enhancement may involve inhibition of SLDR with RFS-2000 plus etoposide, but other mechanisms may be involved in the combined treatment including CPT-11.