SIRT2 modulates VEGFD-associated lymphangiogenesis by deacetylating EPAS1 in human head and neck cancer.

Sirtuin 2 (SIRT2) is one of seven mammalian homologs of silent information regulator 2 (Sir2) and an NAD+ -dependent deacetylase; however, its critical role in lymphangiogenesis remains to be explored. We investigate SIRT2 mediated regulation of vascular endothelial growth factor D (VEGFD) expression and lymphangiogenesis by deacetylating endothelial PAS domain protein 1 (EPAS1) in head and neck cancer (HNC) in vitro and in vivo. In this study, we report that SIRT2, rather than other members of the Sir2 family, reduces the expression of VEGFD and lymphangiogenesis in hypoxia-induced HNC cells and transplanted HNC mice models by reducing EPAS1 acetylation at Lys674 and decreasing the transcriptional activity of EPAS1 target genes. The expression of SIRT2 was closely related to the expression of VEGFD, lymphangiogenesis in subcutaneously transplanted mice models, and lymphangiogenesis in patients with HNC. Our results suggest that SIRT2 plays a central role in tumor lymphangiogenesis via deacetylating EPAS1 protein. Reagents targeting the NAD+ -dependent deacetylase activity of SIRT2 would be beneficial for inhibiting tumor lymphangiogenesis and treating other hypoxia-related diseases.

Y4lO of Rhizobium sp. strain NGR234 is a symbiotic determinant required for symbiosome differentiation.

Type 3 (T3) effector proteins, secreted by nitrogen-fixing rhizobia with a bacterial T3 secretion system, affect the nodulation of certain host legumes. The open reading frame y4lO of Rhizobium sp. strain NGR234 encodes a protein with sequence similarities to T3 effectors from pathogenic bacteria (the YopJ effector family). Transcription studies showed that the promoter activity of y4lO depended on the transcriptional activator TtsI. Recombinant Y4lO protein expressed in Escherichia coli did not acetylate two representative mitogen-activated protein kinase kinases (human MKK6 and MKK1 from Medicago truncatula), indicating that YopJ-like proteins differ with respect to their substrate specificities. The y4lO gene was mutated in NGR234 (strain NGROmegay4lO) and in NGR Omega nopL, a mutant that does not produce the T3 effector NopL (strain NGR Omega nopLOmegay4lO). When used as inoculants, the symbiotic properties of the mutants differed. Tephrosia vogelii, Phaseolus vulgaris cv. Yudou No. 1, and Vigna unguiculata cv. Sui Qing Dou Jiao formed pink effective nodules with NGR234 and NGR Omega nopL Omega y4lO. Nodules induced by NGR Omega y4lO were first pink but rapidly turned greenish (ineffective nodules), indicating premature senescence. An ultrastructural analysis of the nodules induced by NGR Omega y4lO revealed abnormal formation of enlarged infection droplets in ineffective nodules, whereas symbiosomes harboring a single bacteroid were frequently observed in effective nodules induced by NGR234 or NGR Omega nopL Omega y4lO. It is concluded that Y4lO is a symbiotic determinant involved in the differentiation of symbiosomes. Y4lO mitigated senescence-inducing effects caused by the T3 effector NopL, suggesting synergistic effects for Y4lO and NopL in nitrogen-fixing nodules.

Symbiosis-promoting and deleterious effects of NopT, a novel type 3 effector of Rhizobium sp. strain NGR234.

Establishment of symbiosis between certain host plants and nitrogen-fixing bacteria ("rhizobia") depends on type 3 effector proteins secreted via the bacterial type 3 secretion system (T3SS). Here, we report that the open reading frame y4zC of strain NGR234 encodes a novel rhizobial type 3 effector, termed NopT (for nodulation outer protein T). Analysis of secreted proteins from NGR234 and T3SS mutants revealed that NopT is secreted via the T3SS. NopT possessed autoproteolytic activity when expressed in Escherichia coli or human HEK 293T cells. The processed NopT exposed a glycine (G50) to the N terminus, which is predicted to be myristoylated in eukaryotic cells. NopT with a point mutation at position C93, H205, or D220 (catalytic triad) showed strongly reduced autoproteolytic activity, indicating that NopT is a functional protease of the YopT-AvrPphB effector family. When transiently expressed in tobacco plants, proteolytically active NopT elicited a rapid hypersensitive reaction. Arabidopsis plants transformed with nopT showed chlorotic and necrotic symptoms, indicating a cytotoxic effect. Inoculation experiments with mutant derivatives of NGR234 indicated that NopT affected nodulation either positively (Phaseolus vulgaris cv. Yudou No. 1; Tephrosia vogelii) or negatively (Crotalaria juncea). We suggest that NopT-related polymorphism may be involved in evolutionary adaptation of NGR234 to particular host legumes.

Therapeutic ultrasound potentiates the anti-nociceptive and anti-inflammatory effects of curcumin to postoperative pain via Sirt1/NF-κB signaling pathway.

Background: Postoperative pain has well defined and is perceived by patients as one of the most obnoxious aspects of surgical pain. The aim of this study was to determine whether the combination of Therapeutic ultrasound (TUS) and Curcumin (CUR) resulted in an enhancement of their pain relieving activities in a rat model of postoperative pain. Methods: We explored the effect of these treatment and their interaction with signal transduction pathways involved in inflammatory. In this study, TUS and CUR alone or in combination were administered prior to or simultaneously with or after the incisional surgery. Results: At the start time of administration, we observed that the TUS plus CUR treatment reduced the mean paw withdrawal threshold more efficiently than CUR alone. Then we demonstrated that TUS potentiates the antinociceptive effect of CUR in a rat model of chronic postoperative pain and that the combination could facilitate the recovery of surgical pain. However, preventive value was not statistically significant when the treatments were given prior to the incisional surgery. We provide evidence that TUS plus CUR administrations were safe and significantly reduced the ED50 compared to treatment with the single CUR treatment in rats. TUS plus CUR administrations decreases incisional surgery induced activation of inflammatory cells and down-regulation of chemokines and proinflammatory cytokines, MCP-1, MIP-1α, IL-1ß, and TNF-α through regulating Sirt1/NF-κB signaling pathway. Conclusions: Taken together, our results indicate that the combinations of TUS and CUR can be more effective in the anti-nociceptive effects than the treatment with CUR alone.

Curcumin induces G2/M cell cycle arrest and apoptosis of head and neck squamous cell carcinoma in vitro and in vivo through ATM/Chk2/p53-dependent pathway.

Studies have demonstrated that curcumin (CUR) exerts its tumor suppressor function in a variety of human cancers including head and neck squamous cell carcinoma (HNSCC). However, the exact underlying molecular mechanisms remain obscure. Here, we aim to test whether CUR affects ATM/Chk2/p53 signaling pathway, leading to the induction of cell cycle arrest, inhibition of angiogenesis of HNSCC in vitro and in vivo. To this end, we conducted multiple methods such as MTT assay, Invasion assay, Flow cytometry, Western blotting, RT-PCR, and transfection to explore the functions and molecular insights of CUR in HNSCC. We observed that CUR significantly induced apoptosis and cell cycle arrest, inhibited angiogenesis in HNSCC. Mechanistically, we demonstrated that CUR markedly up-regulated ATM expression and subsequently down-regulated HIF-1α expression. Blockage of ATM production totally reversed CUR induced cell cycle arrest as well as anti-angiogenesis in HNSCC. Moreover, our results demonstrated that CUR exerts its antitumor activity through targeting ATM/Chk2/p53 signal pathway. In addition, the results of xenograft experiments in mice were highly consistent with in vitro studies. Collectively, our findings suggest that targeting ATM/Chk2/p53 signal pathway by CUR could be a promising therapeutic approach for HNSCC prevention and therapy.

[The expression of Aeromonas hydrophila ompTS gene and the immunogenicity of recombinant OmpTS].

Primers were designed based on ompTS gene reported recently. With the specific primers, one target fragment about 1024 bp lacking the signal sequence of ompTS gene was amplified from A. hydrophila genomic DNA via PCR. The ompTS gene was hyperexpressed using gene fusion expression vector pRSET system, and the recombinant OMP exhibited a size of 39.9 kD with SDS-PAGE and Western blot analysis, which showed about 51% of total lysate proteins. Antibody to the purified recombinant OMP reacted not only to the recombinant OMP but also to the purified OMPs from A. hydrophila in ELISA and the 36.9 kD OMP in Western blot. The result indicates that the recombinant OMP has the same epitope with the nature one.