[Effect of curcumin on radiosensitization of CNE-2 cells and its mechanism].

OBJECTIVE: To investigate the effect of curcumin (Cur) on radiosensitivity of nasopharyngeal carcinoma cell CNE-2 and its mechanism. METHOD: The effect of curcumin on radiosensitivity was determined by the clone formation assay. The cell survival curve was fitted by Graph prism 6. 0. The changes in cell cycle were analyzed by flow cytometry (FCM). The differential expression of long non-coding RNA was detected by gene chip technology. Part of differentially expressed genes was verified by Real-time PCR. RESULT: After 10 micro mol L-1 Cur had worked for 24 h, its sensitization enhancement ratio was 1. 03, indicating that low concentration of curcumin could increase the radiosensitivity of nasopharyngeal carcinoma cells; FCM displayed a significant increase of G2 phase cells and significant decrease of S phase cells in the Cur combined radiation group. In the Cur group, the GUCY2GP, H2BFXP, LINC00623 IncRNA were significantly up-regulated and ZRANB2-AS2 LOC100506835, FLJ36000 IncRNA were significantly down-regulated. CONCLUSION: Cur has radiosensitizing effect on human nasopharyngeal carcinoma CNE-2 cells. Its mechanism may be related to the changes in the cell cycle distribution and the expression of long non-coding IncRNA.

Cloning and characterization of a shrimp ML superfamily protein.

ML superfamily proteins, including MD-1, MD-2, Niemann-Pick type C2 (Npc2) protein, GM2 activator protein, phosphatidylinositol/phosphatidylglycerol transfer protein (PG/PI-TP) and mite allergen Der p 2, bind to specific lipids and play important roles in lipid-recognition and metabolism. Among these ML (MD-2-related lipid-recognition) proteins, MD-2 is essential for lipopolysaccharide (LPS) signaling and the following secretion of proinflammatory factors. In this report, we identified the cDNA and gene of an ML protein from an important white shrimp Litopenaeus vannamei and named it LvML. The gene consists of four exons and three introns. The putative LvML contains 6 cysteines which may form 3 disulfide bonds that are conserved in ML proteins. Reverse transcription PCR analysis showed that in the examined tissues LvML mRNA is only expressed in the hepatopancreas, while not in hemocytes, eyestalk, gill, heart, stomach, intestine, nerve core, muscle or pyloric caecum. Its expression is positively regulated after injection of LPS. Then enzyme-linked immunosorbent assay showed that the recombinant LvML possessed activity of binding to LPS, and that the binding was inhibited by pre-incubation with LPS. We suggested that the LvML may play roles in the shrimp innate immunity.

Shrimp NF-κB binds to the immediate-early gene ie1 promoter of white spot syndrome virus and upregulates its activity.

The immediate-early gene ie1 carried by white spot syndrome virus (WSSV) exhibits very strong promoter activity and expresses highly throughout the infection cycle. Here we identified a NF-κB binding motif in the ie1 promoter region. Electrophoretic mobility shift assays indicated that the recombinant Rel homology domain (RHD) of shrimp NF-κB homolog LvRelish bound to the putative NF-κB site in the ie1 promoter. A transactivity assay of the WSSV ie1 promoter in Drosophila Schneider 2 cells demonstrated that LvRelish could increase ie1 promoter activity. These results show that shrimp NF-κB homolog LvRelish transactivates WSSV ie1 gene expression and contributes to its high promoter activity. Further transactivation assays showed that WSSV IE1 protein expression upregulated the promoter activities of WSSV ie1 gene and antimicrobial peptide genes regulated by the NF-κB system. We suggested that WSSV may annex the shrimp NF-κB system, which it uses to enhance the expression of viral immediate-early genes.

Identification and functional study of a shrimp Dorsal homologue.

Rel/NF-kappaB transcription factors play central roles in induction and regulation of innate immune responses. Here, identification and functional analysis of LvDorsal, a Dorsal homologue from the Pacific white shrimp Litopenaeus vannamei, were described. The full-length cDNA of LvDorsal is 2204bp with an open reading frame that encodes 400 amino acids. The deduced LvDorsal contains a conserved Rel homology domain (RHD), an IPT (Ig-like, plexins and transcription factors) domain and a nucleus localization signal, suggesting that it belongs to the class II NF-kappaB. RT-PCR analysis showed that LvDorsal mRNAs were expressed in all the tissues tested, including gill, epidermis, hemocytes, intestine, stomach, eyestalk, brain, hepatopancreas, muscle, heart and pyloric caecum. Immunofluorescence assay showed that recombinant LvDorsal was translocated into the nucleus of Drosophila S2 cells. Electrophoretic mobility shift assay illustrated that recombinant LvDorsal RHD from S2 cells bound specifically with D. melanogaster kappaB motifs. Additionally, the dual-luciferase reporter assays indicated that LvDorsal could transactivate the reporter gene controlled by the 5' flanking region of shrimp penaeidin-4 and Drosophila attacin genes, suggesting that LvDorsal can regulate the transcription of shrimp penaeidin-4 gene. Study of LvDorsal will help us to better understand shrimp immunity and may help to obtain more effective methods to prevent shrimp diseases.

Identification and functional study of a shrimp Relish homologue.

Rel/NF-kappaB transcription factors play central roles in induction and regulation of innate immune responses. Here we describe the identification and functional analysis of a Relish homologue, LvRelish and its shorter isoform sLvRelish, from the Pacific white shrimp, Litopenaeus vannamei. The LvRelish gene has 22 exons in approximately 15 kb genomic sequence. The full-length cDNA of LvRelish is 4071 bp with an open reading frame that encodes 1207 amino acids. LvRelish contains a conserved Rel homology domain (RHD), a nucleus localization signal, an IkappaB-like domain (six ankyrin repeats), and a death domain, suggesting that it belongs to the class I NF-kappaB. sLvRelish cDNA is 1051 bp encoding 317 amino acids. It shares the RHD region with LvRelish. RT-PCR analysis showed that LvRelish and sLvRelish mRNAs were expressed at different levels in tissues. Western blot analysis showed that recombinant intact LvRelish could be cleaved into two fragments in S2 cells, and immunofluorescence assay showed that the plasmid-expressed LvRelish protein was seen both in the cytoplasm and the nucleus. Electrophoretic mobility shift assay showed that recombinant RHD of LvRelish in S2 cells bound specifically with Drosophila melanogaster kappaB motifs in vitro. Both the LvRelish and its RHD domain transactivated the reporter gene controlled by the 5' flanking region of penaeidin 4, an antibacterial peptide of shrimp, suggesting that LvRelish can regulate the transcription of penaeidin 4 gene. Identification of LvRelish will help us better understand shrimp immunity and may help obtain more effective methods to prevent shrimp diseases.

Cloning of IRAK1 and its upregulation in symptomatic mandarin fish infected with ISKNV.

Interleukin-1 receptor activated kinases (IRAKs) play crucial roles in the Toll-like receptor (TLR) mediated signal transduction pathways that control host innate immune responses. Here we report the cloning of an IRAK1 cDNA (named ScIRAK1) from the mandarin fish. The predicted ScIRAK1 peptide contains a death domain and a serine/threonine-specific kinase domain. Quantitative RT-PCR showed that ScIRAK1 mRNA was primarily expressed in blood cells and posterior kidney. Seven days following infection with infectious spleen and kidney necrosis virus (ISKNV), the ScIRAK1 mRNA level was significantly higher in the blood cells of clinically symptomatic fish than in the blood cells of asymptomatic fish or control fish injected with phosphate-buffered saline. Additional experiments showed that overexpression of ScIRAK1 in the 293T cells could induce NF-kappaB activation. These results suggest that ScIRAK1 may play a role in the pathology of ISKNV infection in the mandarin fish.

The alpha inhibitor of NF-kappaB (IkappaBalpha) from the mandarin fish binds with p65 NF-kappaB.

The NF-kappaB/IkappaBalpha pathway plays an important role in the regulation of immune and inflammatory responses. IkappaBalpha is an inhibitory molecule that sequesters transcription activator NF-kappaB dimer in the cytoplasm of unstimulated cells. Here, we isolated the full-length cDNAs of the mandarin fish (Siniperca chuatsi) alpha inhibitor of NF-kappaB (ScIkappaBalpha) and p65 NF-kappaB (Scp65). Multiple sequence alignments showed that the amino acid sequences of both ScIkappaBalpha and Scp65 contain conserved domains similar to those of mammalian counterparts. Protein pull-down and coimmunoprecipitation assays showed that ScIkappaBalpha directly bound with Scp65. Real-time quantitative PCR analysis showed that ScIkappaBalpha mRNA was constitutive in all mandarin fish tissues detected. After challenge with infectious spleen and kidney necrosis virus (ISKNV), the mRNA level of ScIkappaBalpha was decreased nearly 6 fold in the spleen. This result suggests that the NF-kappaB/IkappaBalpha pathway in mandarin fish may play a role in the immune response against ISKNV.

An immune deficiency homolog from the white shrimp, Litopenaeus vannamei, activates antimicrobial peptide genes.

Invertebrates rely on innate immunity as the first line defense against microbes. In Drosophila, the inducible antimicrobial peptides (AMPs) regulated by the Toll and immune deficiency (Imd) pathways are important effectors in innate immunity. Here we report an immune deficiency homolog (LvIMD) from the white shrimp, Litopenaeus vannamei. The full-length cDNA of LvIMD is 758 bp with an open reading frame of 483 bp that encodes a putative protein of 160 amino acids including a death domain at the C-terminus. LvIMD death domain shows similarity to that of Drosophila IMD and human receptor interacting protein 1 (RIP1) of the tumor necrosis factor receptor (TNFR) pathway, with 27.9% and 26.4% identity, respectively. Phylogenetic analysis shows that LvIMD clusters with a predicted protein from the starlet sea anemone (Nematostella vectensis) independent to insect IMDs and vertebrates RIP1s. LvIMD mRNA is expressed in most tissues and is induced in hepatopancreas and hemocytes after immune challenge. Luciferase reporter assays confirm that LvIMD is able to induce the expression of AMP genes, including Drosophila Attacin A and shrimp Penaeidin 4 in S2 cells. To our knowledge, this is the first report that LvIMD participates in innate signaling to activate the expression of AMP genes in shrimp.

A novel prophenoloxidase 2 exists in shrimp hemocytes.

The prophenoloxidase (proPO)-activating system in crustaceans and other arthropods is regarded as a constituent of the immune system and plays an important role in defense against pathogens. Hitherto in crustaceans, only one proPO gene per species has been identified. Here we report the identification of a novel proPO-2 (LvproPO-2) from the hemocytes of Litopenaeus vannamei, which shows 72% identity to proPO-1 (LvproPO-1) cloned previously. Northern blotting analysis and quantitative real-time PCR reveal that LvproPO-2 is mainly expressed in the hemocytes, and its expression is down-regulated in shrimp challenged with white spot syndrome virus (WSSV). Western blotting analysis shows that most LvproPO-2/LvPO-2 (L. vannamei phenoloxidase-2) exists in the hemocytes, but not in plasma of L. vannamei. LvproPO-2/LvPO-2 could be detected on the hemocyte surface and the nucleus of hemocytes by indirect immunofluorescence assay (IFA). These findings provide insight into the molecular biological basis for further studying on the defense mechanism of shrimp innate immunity, especially on the proPO-activating system and melanization cascade of shrimp.

A novel C-type lectin from the shrimp Litopenaeus vannamei possesses anti-white spot syndrome virus activity.

C-type lectins play key roles in pathogen recognition, innate immunity, and cell-cell interactions. Here, we report a new C-type lectin (C-type lectin 1) from the shrimp Litopenaeus vannamei (LvCTL1), which has activity against the white spot syndrome virus (WSSV). LvCTL1 is a 156-residue polypeptide containing a C-type carbohydrate recognition domain with an EPN (Glu(99)-Pro(100)-Asn(101)) motif that has a predicted ligand binding specificity for mannose. Reverse transcription-PCR analysis revealed that LvCTL1 mRNA was specifically expressed in the hepatopancreas of L. vannamei. Recombinant LvCTL1 (rLvCTL1) had hemagglutinating activity and ligand binding specificity for mannose and glucose. rLvCTL1 also had a strong affinity for WSSV and interacted with several envelope proteins of WSSV. Furthermore, we showed that the binding of rLvCTL1 to WSSV could protect shrimps from viral infection and prolong the survival of shrimps against WSSV infection. Our results suggest that LvCTL1 is a mannose-binding C-type lectin that binds to envelope proteins of WSSV to exert its antiviral activity. To our knowledge, this is the first report of a shrimp C-type lectin that has direct anti-WSSV activity.

Changes in mortality and immunological variables of Litopenaeus vannamei parents and their filial families infected with white spot syndrome under different experimental conditions.

In order to find changes in mortality and immunological variables of Litopenaeus vannamei parents and the filial WSSV-resistant and -susceptible families after infection with WSSV under different experimental conditions, the haemolymph total haemocyte count (THC), phenoloxidase (PO), and superoxide dismutase (SOD) activities were measured at days 0, 1, 3, 6, 9, 12 and 15 after challenge and shrimp mortality was also recorded. When shrimps were challenged with 10(-3) (1.29x10(6)copiesmL(-1)), 10(-4) (1.29x10(5)copiesmL(-1)) or 10(-5) (1.29x10(4)copiesmL(-1)) WSSV stock solution (0.1mLshrimp(-1)), the cumulative mortalities (mean+/-S.E.) on day 15 were 100+/-0%, 79.3+/-1.1%, and 21.7+/-2.3%, respectively. Among shrimps challenged with 10(-4) (1.29x10(5)copiesmL(-1)) WSSV dilution (0.1mLshrimp(-1)), the cumulative mortalities (mean+/-S.E.) on day 15 in high-density (100shrimpsm(-3)), middle-density (50shrimpsm(-3)), and low-density (25shrimpm(-3)) groups were 95.5+/-0%, 84.7+/-0%, and 72.3+/-0%, respectively. The immunological variables including THC, PO, and SOD were decreased significantly at the beginning of infection stage, while these immunological variables for survivors reached almost the similar levels to the non-infection control group on day 15 after challenge with 10(-4) (1.29x10(5)copiesmL(-1)) WSSV dilution (0.1mLshrimp(-1)). Cumulative mortality (mean+/-S.E.) on day 15 in 17 filial families (G(2)) ranged from 13.3+/-1.9% to 100+/-0% when shrimps were challenged with 10(-4) (1.29x10(5)copiesmL(-1)) WSSV dilution (0.1mLshrimp(-1)). Although, the PO and SOD activities for shrimps in the WSSV-resistant family were slightly higher than those in the WSSV-susceptible family at the same sampling time after infection, these differences were not significant (p<0.05).

Molecular cloning of two C1q-like cDNAs in mandarin fish Siniperca chuatsi.

C1q, a subunit of the C1 complex, plays a key role in the recognition of immune complexes to initiate the classical complement pathway. In this study, we reported two C1q-like cDNAs from mandarin fish (Siniperca chuatsi), mC1q-like-1 (mC1qL1) and mC1q-like-2 (mC1qL2). The full-length cDNA of mC1qL1was 990bp, containing a 71bp 5'-untranslated region (UTR), an open reading frame (ORF) of 723bp, and a 196bp long 3'-UTR. mC1qL2 cDNA was 1193bp, containing a 100bp 5'-UTR, followed by an ORF of 756bp and a 3'-UTR of 337bp. mC1qL1 and mC1qL2 share 29% identity in amino acid sequence. Both mC1qL1 and mC1qL2 contained three parts: a short amino-terminal region, a collagen-like region and a carboxyl-terminal globular C1q domain. The phylogenetic analysis showed that mC1qL1 clustered with two Danio rerio hypothetical proteins and further grouped with C1q proteins, while mC1qL2 clustered with C1qA proteins from other species. In healthy mandarin fish, mC1qL1 and mC1qL2 were expressed in all tissues tested, including liver, spleen, head kidney, caudal kidney, intestine and gill. mC1qL1 was highly expressed in head kidney, while mC1qL2 was mainly expressed in spleen. The expression level of mC1qL1 and mC1qL2 in liver were not changed obviously and mC1qL2 was significantly changed (p<0.05) in spleen after infectious spleen and kidney necrosis virus (ISKNV) infection. Mandarin fish C1q may play a role in response to ISKNV infection.

Tumor necrosis factor-alpha gene from mandarin fish, Siniperca chuatsi: molecular cloning, cytotoxicity analysis and expression profile.

In this report, we cloned a cDNA and the gene of mandarin fish (Siniperca chuatsi) tumor necrosis factor-alpha (TNF-alpha). The length of TNF-alpha cDNA was 1461 bp, contained an open reading frame (ORF) of 762 bp, which encoded 253 amino acids. The positions of cysteine residues, transmembrane sequence, and protease cleavage site were similar with other reported fish TNF-alpha and mammalian TNF-alpha. Mandarin fish TNF-alpha gene has a length of 1940 bp, and consists of four exons and three introns. There are three NF-kappaB/rel regulatory/binding sites in gene's 5' flanking region. Expression of mandarin fish TNF-alpha mRNA was constitutive in all tissues detected. After challenge of infectious spleen and kidney necrosis virus (ISKNV), which results a high mortality rate in mandarin fish and has caused huge economic losses in China, the expression of TNF-alpha mRNA in head kidney and kidney did not show significant changes from 0 day to 15 days post-infection. While in blood and spleen, the gene's mRNA showed up-regulations in 4 days post-infection and down-regulations in 15 days post-infection, which indicated the mRNA expression of TNF-alpha may related to the infection of ISKNV and the survival of mandarin fish. Mature form of recombinant mandarin fish TNF-alpha protein (400-4000 ng/ml) showed an evident apoptosis induction ability of human HeLa cells, in a dose-dependent manner, although to a lesser extent compared to the recombinant human TNF-alpha protein (200 ng/ml).

A Toll receptor in shrimp.

Outbreaks of infectious diseases have resulted in high mortality and huge economic losses in penaeid shrimp culture. Interest in understanding shrimp immunity has increased because of its importance in disease control. Here we report cDNA cloning of a Toll receptor from the white shrimp Litopenaeus vannamei. L. vannamei Toll (lToll) is 926 residues, with a putative signal peptide of 19 residues. The protein contains distinct structural/functional motifs of the Toll like receptor (TLR) family, including an extracellular domain containing 16 leucine-rich repeats (LRRs) flanked by cysteine-rich motifs and a cytoplasmic Toll/interleukin-1 receptor (TIR) domain. The lToll TIR domain showed high similarity to Apis mellifer Toll and Drosophila melanogaster Toll, with 59.9% and 54.3% identity, respectively. Reverse-transcription polymerase chain reaction (RT-PCR) analysis showed that lToll was expressed in hemocyte, gill, heart, brain, stomach, intestine, pyloric caecum, muscle, nerve and spermary, with a lower expression level in eyestalk and hepatopancreas. Identification of lToll will help to elucidate the Toll pathway in shrimp innate immunity.

Profiling of differentially expressed genes in hepatopancreas of white spot syndrome virus-resistant shrimp (Litopenaeus vannamei) by suppression subtractive hybridisation.

In order to find immune-relevant factors responsible for virus resistance and response to the virus infection, the suppression subtractive hybridisation method was employed to identify differentially expressed genes and their expression profiles in the hepatopancreas of the white spot syndrome virus (WSSV) resistant and susceptible Pacific white shrimp (Litopenaeus vannamei). Two forward subtractive libraries (at 0 and 48h time point) and two reverse subtractive libraries (at 0 and 48h time point) were constructed, and more than 1200 clones were sequenced, of which 40 differentially expressed genes were identified. These genes encode proteins corresponding to a wide range of functions, including defence-related proteins, enzymes, transcription factors, apoptotic-related proteins, intracellular components potentially related to signaling cascades, metabolic proteins, and cytoskeletal protein. Five genes (laccase, carboxypeptidase B, H(+)-transporting ATP synthase, Acyl-ConA-binding protein (ACBP), and cortical granule protein with LDL-receptor) are found for the first time in shrimp and their expressions were up-regulated in the virus-resistant shrimp. Among the 40 genes, 30 showed up-regulation in the virus-resistant shrimp comparing with susceptible shrimp, while 10 genes showed down-regulation. Haemocyanin was the most abundant gene in our forward subtractive libraries. In addition, chathepsin L, ecdysteroid regulated protein, zinc proteinase, lectin, sterol carrier protein-X, lysozyme, cortical granule protein with LDL-receptor, leucine-rich repeat LGI family, fatty acid binding protein, and preamylase all showed up-regulation in the resistant shrimp. Furthermore, a number of genes encoding apoptotic-related proteins and antioxidant enzymes were expressed at a higher level in the virus-resistant shrimp. The high expression of the immune-relevant genes in response to the virus infection provides a new insight for further study in the shrimp innate immunity.

Molecular cloning, expression of orange-spotted grouper goose-type lysozyme cDNA, and lytic activity of its recombinant protein.

Lysozyme acts as a non-specific innate-immunity molecule against the invasion of bacteria pathogens. A leukocyte cDNA library of orange-spotted grouper Epinephelus coioides was constructed and the goose-type (g-type) lysozyme cDNA was isolated. The complete cDNA consists of an open reading frame of 585 bp encoding a protein of 194 amino acids. This protein shows a 72.2% amino acid sequence identity with the flounder g-type lysozyme. Similar to most other species, the glu catalytic residue in g-type lysozymes of the grouper is conserved. Furthermore, like the flounder and carp, the 4 conserved cysteine residues identified in avian and mammalian g-type lysozymes were also absent from the grouper. Northern blot analysis indicated that the g-type lysozyme was expressed in intestine, liver, spleen, anterior kidney, posterior kidney, heart, gill, muscle and leukocytes. In addition, RT-PCR analysis detected the g-type lysozyme transcripts in the stomach, brain and ovary. When an orange-spotted grouper was injected with Vibrio alginolyticus, the number of lysozyme mRNA transcripts detected in the stomach, spleen, anterior kidney, posterior kidney, heart, brain and leucocytes increased 72 h after injection. Recombinant grouper g-type lysozyme produced in the Escherichia coli expression system showed lytic activity against Micrococcus lysodeikticus, V. alginolyticus from Epinephelus fario, V. vulnificus from culture water, Aeromonas hydrophila from soft-shell turtle, A. hydrophila from goldfish and V. parahaemolyticus, Pseudomonas fluorescens and V. fluvialis from culture water.