The C-type lectin receptors （CLRs） belong to a large family of proteins that contain a carbohydrate recognition domain （CRD） and calcium binding sites on their extracellular domains. Recent studies indicate that m...The C-type lectin receptors （CLRs） belong to a large family of proteins that contain a carbohydrate recognition domain （CRD） and calcium binding sites on their extracellular domains. Recent studies indicate that many CLRs, such as Dectin-1, Dectin-2 and Mincle, function as pattern recognition receptors （PRRs） recognizing carbohydrate ligands from infected microorganisms. Upon ligand binding, these CLRs induce multiple signal transduction cascades through their own immunoreceptor tyrosine-based activation motifs （ITAMs） or interacting with ITAM-containing adaptor proteins such as FcRy. Emerging evidence indicate that CLR-induced signaling cascades lead to the activation of nuclear factor kappaB （NF-KB） family of transcriptional factors through a Syk- and CARD9-dependent pathway（s）. The activation of NF-κB plays a critical role in the induction of innate immune and inflammatory responses following microbial infection and tissue damages. In this review, we will summarize the recent progress on the signal transduction pathways induced by CLRs. and how these CLRs activate NF-κB and contribute to innate immune and inflammatory responses.展开更多
Background:The C-type lectin receptor(CLR)expressed by DCs participates in the recognition and capture of various glycosylated self-antigens and pathogens.Understanding the diversity of the CLR expressed by DCs,as wel...Background:The C-type lectin receptor(CLR)expressed by DCs participates in the recognition and capture of various glycosylated self-antigens and pathogens.Understanding the diversity of the CLR expressed by DCs,as well as their role in maintaining the balance between Th1-type and Th2-type cytokines would promote the understanding of the pathogenesis of many diseases including preeclampsia(PE).Methods:DCs were isolated from the placentae of healthy women who underwent normal pregnancies and infected with a CLR lentiviral(LV)vector for gene overexpression or small interfering RNA(siRNA)knockdown.DCs were cocultured with T-cells and EVCTs,and five groups were established as follows:Group 1-DCs from healthy women who underwent normal pregnancies,Group 2-DCs from women with preeclampsia(PE),Group 3-DCs infected with empty LV vectors,Group 4-DCs infected with a CLR LV vector for gene overexpression,and Group 5-DCs infected with a CLR LV vector for siRNA knockdown.The levels of Th1-and Th2-type cytokines were measured in all groups.Results:The levels of Th1-type cytokines were significantly higher in women with PE than in those with normal pregnancies(P<0.05).Among these five groups,the Th1/Th2 ratio of Group 5 was highest(P<0.05).There was no difference in the Th1/Th2 ratio between Groups 1 and 3.Conclusions:There was a Th1/Th2 imbalance in women with PE displaying Th1-type immunity.CLR-overexpressing DCs showed a diminished capacity to polarize na?ve T-cells into Th1 effector cells.The impaired Th1 response in DCs was rescued by CLR siRNA knockdown.In conclusion,DCs may affect the production of cytokines and the migration of T-cells through CLR-mediated signaling pathways during pregnancy.展开更多
CD209,a transmembrane lectin belonging to the C-type lectin family,can recognize carbohydrates on the surface of host cells and invading pathogens,and play an important role in cell adhesion and migration,pathogen rec...CD209,a transmembrane lectin belonging to the C-type lectin family,can recognize carbohydrates on the surface of host cells and invading pathogens,and play an important role in cell adhesion and migration,pathogen recognition and immune activation.Although well characterized in mammals,CD209 is still under-researched in fish.Here,we report a CD209-like gene,which was named SsCD209like,in black rockfish Sebastes schlegelii,and analyzed its structure features,expression patterns and ligand-binding activities.SsCD209like displays structural similarities to mammalian CD209s,with a cytosolic tail at N-terminus,a transmembrane region and an extracellular part containing a neck region and a CRD at C-terminus.The extracellular region and the neck region of SsCD-209like can both form dimers,which is different with the tetramer in human homologue.This result demonstrates the multimerization of CD209 homologue in fish for the first time.The EPN motif,a functional motif participating in sugar binding and affinity determination,is conserved in the CRD of SsCD209like,which is consistent with the higher binding strength of this lectin to L-fucose,D-GlcNAc and D-mannose.The binding of SsCD209like to different bacteria strains and bacteria-derived pathogen associated molecular patterns(PAMPs)are also observed in a dose-dependent manner.Results in this study show the sequence and structure features of SsCD209like and demonstrate its binding properties as a pathogen recognition receptor,which promotes our understanding of CD209 homologues in fish and provides basis for more in-depth studies of this molecule in the future.展开更多
C-type lectins(CTLs)are a superfamily of Ca^(2+)-dependent carbohydrate-recognition proteins,and an important pattern recognition receptor(PRR)in insect innate immunity which can mediate humoral and cellular immunity ...C-type lectins(CTLs)are a superfamily of Ca^(2+)-dependent carbohydrate-recognition proteins,and an important pattern recognition receptor(PRR)in insect innate immunity which can mediate humoral and cellular immunity in insects.In this study,we report a novel dual carbohydrate-recognition domain(CRD)CTL from Plutella xylostella which we designate PxIML.PxIML is a protein with a 969 bp open reading frame(ORF)encoding 322 amino acids,containing a signal peptide and a dual-CRD with EPN(Glu_(124)-Pro_(125)-Asn_(126))and QPD(Gln_(274)-Pro_(275)-Asp_(276))motifs.The expression of PxIML mRNA in the fat body was significantly higher than in hemocytes and midgut.The relative expression levels of PxIML in the whole insect and the fat body were significantly inhibited after infection with Bacillus thuringiensis 8010(Bt8010)at 18 h,while they were significantly upregulated after infection with Serratia marcescens IAE6 or Pichia pastoris.The recombinant PxIML(rPxIML)protein could bind to the tested pathogen-associated molecular patterns(PAMPs),and the bacteria of Enterobacter sp.IAE5,S.marcescens IAE6,Staphylococcus aureus,Escherichia coli BL21,and Bt8010 in a Ca^(2+)-dependent manner,however,it showed limited binding to the fungus,P.pastoris.The rPxIML exhibited strong activity in the presence of Ca^(2+) to agglutinate Bt8010,Enterobacter sp.IAE5 and S.aureus,but it only weakly agglutinated with E.coli BL21,and could not agglutinate with S.marcescens IAE6 or P.pastoris.Furthermore,the rPxIML could bind to hemocytes,promote the adsorption of hemocytes to beads,and enhance the phenoloxidase(PO)activity and melanization of P.xylostella.Our results suggest that PxIML plays an important role in pathogen recognition and in mediating subsequent humoral and cellular immunity of P.xylostella.展开更多
Acting as one of the pattern recognition receptors (PRRs), C-type lectin is believed to mediate pathogen recognition and plays an important role in the clearance of pathogens as part of the innate immune system. In th...Acting as one of the pattern recognition receptors (PRRs), C-type lectin is believed to mediate pathogen recognition and plays an important role in the clearance of pathogens as part of the innate immune system. In this work, a novel C-type lectin gene (named LvLec1) was cloned from the shrimp Litopenaeus vannamei. The ORF of LvLec1 is 510 bp, encoding 169 amino acids. The deduced amino acid sequence contains a putative signal peptide of 19 amino acids at the N-terminal and a carbohydrate recognition domain (CRD) at the C-terminal. LvLec1 was mainly expressed in the hepatopancreas. Real-time PCR analysis indicated that the level of LvLec1 transcripts significantly changed in the hepatopancreas after the shrimp were artificially challenged with LPS, Micrococcus lysodeikticus and white spot syndrome virus (WSSV). RNAi-based silencing of LvLec1 resulted in increases in mortality when the shrimp were challenged with WSSV, and the median lethal time was reduced compared with controls. Although there was no characteristic "EPN" (Glu-Pro-Ser) or "QPD" (Gln-Pro-Asp) motif, the recombinant LvLec1, expressed in Escherichia coli BL21 (DE3), could also agglutinate M. lysodeikticus and Vibrio anguillarum. The agglutinating activities were calcium-dependent and could be inhibited by D-mannose, D-glucose, D-galactose and N-Acetyl-D-mannose. These results suggest that LvLec1 might be involved in the immune response against WSSV and bacterial infections and contribute to non-self recognition as a pattern recognition receptor in the innate immune system of the shrimp L. vannamei.展开更多
C-type lectins are among the most significant pattern recognition receptors（PRRs） found in invertebrate. They are a class of carbohydrate-binding proteins that can recognize specific sugar moieties on the surface of...C-type lectins are among the most significant pattern recognition receptors（PRRs） found in invertebrate. They are a class of carbohydrate-binding proteins that can recognize specific sugar moieties on the surface of pathogens. In the present study, a novel C-type lecitn（termed Mj Lectin） from kuruma shrimp Marsupenaeus japonicus was identified. The full-length c DNA of Mj Lectin was 1 245 bp with a 1 011 bp open reading frame（ORF） that encoded a polypeptide of 336 amino acid residues. Mj Lectin consisted of two tandemly arrayed carbohydrate-recognition domains（CRDs）, unlike other reported M. japonicus C-type lectins with only one CRD. It showed a high similarity to other shrimp dual-CRD lectins. Among the Ca2＋-binding Site 2, the tripeptide motif dictating the carbohydrate binding specificity was exhibited as a rare mutant LPN（Leu134-Pro135-Asn136） in CRD1 and a traditional EPN（Glu299-Pro300-Asn301） in CRD2, respectively. Mj Lectin showed a specific expression pattern in both tissue and cellular levels, for its m RNA transcript was mainly expressed in the F-cells of the hepatopancreas. After white spot syndrome virus（WSSV） challenge（3.6×108 virions/μL）, the expression of Mj Lectin in the hepatopancreas was up-regulated significantly at 48 h（P〈0.01） compared with the control group. These results suggested that Mj Lectin might be involved in the innate immune defense against WSSV infection.展开更多
Ten cases of gastrointestinal adenocarcinomas were histochemically investigated fortheir lectin receptors by avidin—biotin-peroxidase complex(ABC)method.Results showed thatgastric adenocarcinomas expressed more types...Ten cases of gastrointestinal adenocarcinomas were histochemically investigated fortheir lectin receptors by avidin—biotin-peroxidase complex(ABC)method.Results showed thatgastric adenocarcinomas expressed more types of lectin receptors than large boweladenocarcinomas.Positive rates of Glc/Man-and GlcNAc-specific lectin receptors in these tu-mors were kigher than those of Gal/GalNAc-and Fuc-specific lectin receptors.From the stom-ach to rectum,the spectrum of the lectin receptors in pericarcinomatous tissues graduallychanged from the gastric type to the rectal type.The expression of lectin receptors ingustrointestinal adenocarcinomas was obviously different Jrom that in their correspondingpericarcinomatous tissues.The increase and decrease of lectin receptor expression,theappearance and disappearance of some types of lectin receptors as well as the change of thereceptor distribution are indirectly regulated by cellular genome.展开更多
As an important pattern recognition receptor(PRR)in the innate immune system,C-type lectin plays an important role in the innate immune process of invertebrates.Two C-type lectins Sp CTL-C and Sp CTL-D were characteri...As an important pattern recognition receptor(PRR)in the innate immune system,C-type lectin plays an important role in the innate immune process of invertebrates.Two C-type lectins Sp CTL-C and Sp CTL-D were characterized from mud crab(Scylla paramamosain).The predicted Sp CTL-C and Sp CTL-D proteins both contain a single carbohydrate-recognition domain(CRD)with key motif Gln-Pro-Ala(QPA)and Met-Pro-Ala(MPA),respectively.Sp CTL-C and Sp CTL-D transcripts distributed in all examined tissues,and the expression level was the highest in hepatopancreas.As PRR,the purifi ed recombinant proteins r Sp CTL-C and r Sp CTL-D have high affi nity for three kinds of pathogen-associated molecular patterns(PAMPs):β-glucan,lipopolysaccharide,and peptidoglycan.Besides,r Sp CTL-D can bind to all nine microorganisms tested,while r Sp CTL-C can bind to seven microorganisms except for Staphylococcus aureus and Micrococcus luteus.Both r Sp CTL-C and r Sp CTL-D showed agglutination activity towards fungi Pichia pastoris and Saccharomyces cerevisiae.However,r Sp CTL-C and r Sp CTL-D exhibited diff erent antimicrobial activities:r Sp CTL-D has a certain inhibitory eff ect on the growth of Vibrio fl uvialis and M.luteus,while r Sp CTL-C has no obvious inhibitory activity.The results show that r Sp CTL-C and r Sp CTL-D had better phagocytosis-promoting eff ect on M.luteus than the negative control.Meanwhile,both r Sp CTL-C and r Sp CTL-D had certain encapsulation-promoting activity.Collectively,two C-type lectins with novel key motifs make an important impact as PRR in immune response towards pathogens.At the same time,they play diff erent functions in the innate immunity of mud crab S.paramamosain.展开更多
The C-type lectin MGL is a pathogen recognition receptor, expressed by dendritic cells (DCs) and macrophages (Mfs), able to bind GalNAc (Tn) carrying structures. This receptor also recognized Tn-TAAs that were interna...The C-type lectin MGL is a pathogen recognition receptor, expressed by dendritic cells (DCs) and macrophages (Mfs), able to bind GalNAc (Tn) carrying structures. This receptor also recognized Tn-TAAs that were internalized, processed and presented by DCs to T cells and it acted as an adjuvant on DCs, highlighting its possible application in anti-cancer vaccination. In this work, we found that this receptor present a seasonal modulation: its expression is higher in winter rather than in summer. The percentage of MGL+ donors displayed a negative trend that dropped to 33% during the summer and increased up to 100% in winter. This modulation could be also ascribed to the circa-annual variation of glucocorticoids, in fact MGL is up-regulated in presence of dexamethasone in vitro. The seasonal variation of this receptor could be an important point in the field of tumor vaccination strategies.展开更多
Eight lectins were used to study 100 cases of breast carcinoma and 56 cases of non-carcinoma breast tissues by lectin affinity histochemical method. The results showed that Bandeirasa Simplicifolia (BSL) and Peanut ag...Eight lectins were used to study 100 cases of breast carcinoma and 56 cases of non-carcinoma breast tissues by lectin affinity histochemical method. The results showed that Bandeirasa Simplicifolia (BSL) and Peanut agglutinin (PNA) had higher positive rates in breast carcinoma than both normal breast and benign lesions (P<0.005). The positive deposit in malignant lesions was mainly located in cytoplasm, while in non-malignant lesions, it was almost lined along the lumen of glands and small ducts (P<0.005). The authors think that expression of PNA-receptor in the cytoplasm might be associated with the mechanism that the tumor could escape from immune attack. Comparison analysis on the normal breast indicated that PNA affinity histoche-mistry would be useful to the understanding of the metabolism of β-D-galactosyl-N-acetyl-D-galactosa-mine during the development of normal breast and histological origin of breast carcinoma.展开更多
Pattern recognition receptor(PRR)is a kind of sensor which is mainly expressed on the surface of innate immune cells.It can recognize pathogen related molecular patterns(PAMPs)or damage related molecular patterns(DAMP...Pattern recognition receptor(PRR)is a kind of sensor which is mainly expressed on the surface of innate immune cells.It can recognize pathogen related molecular patterns(PAMPs)or damage related molecular patterns(DAMPs).The innate immune system uses pattern recognition receptors to recognize pathogenic microorganisms in periodontal tissues and transmit signals to downstream pathways in time,thus triggering immune responses and then eliminating them.PRR has many family members,including toll like receptor family(TLRs),C-type lectin receptor family(CLRs),retinoic acid induced gene I(RIG-I)like receptor family(RLRs)and nucleotide binding oligomer domain(NOD)like receptor family(NLRs).Among them,RLRs are cytoplasmic receptors that recognize dsRNA from RNA viruses and have little association with chronic periodontitis.In this paper,the classification and structure of TLRs,CLRs,NLRs and the role of signal transduction pathway in chronic periodontitis are reviewed.In order to enrich the pathogenesis of periodontitis,provide new ideas for the treatment and prevention of chronic periodontitis.展开更多
Evidence is accumulating that pattern recognition receptor(PRR)C-type lectins(CTL)play essential roles in recognition of pathogens.TcCTL14(accession no.TC00871)contains the most domains among all CTL of Tribolium cast...Evidence is accumulating that pattern recognition receptor(PRR)C-type lectins(CTL)play essential roles in recognition of pathogens.TcCTL14(accession no.TC00871)contains the most domains among all CTL of Tribolium castaneum.Yet the biological function of TcCTL14 remains unclear.In this study,TcCTL14 exhibiting typical motif and domain of CTL was cloned from T.castaneum.The expression pattern analysis showed that TcCTL14 was highly expressed in late pupae and central nervous system,and was upregulated after treatment with Escherichia coli and Staphylococcus aureus,respectively.Analysis of binding affinity revealed that recombinant TcCTL14 not only could bind to lipopolysaccharide and peptidoglycan in a dose-dependent fashion,but possibly could bind to and agglutinate different bacteria in a Ca^(2+)-dependent fashion.Knockdown of TcCTL14 before injection with bacteria led to the downregulation of nuclear factor-κB transcription factors of Toll/IMD and 4 antimicrobial peptides.Knockdown of TcCTL14 also caused suppressed metamorphosis,reduced fecundity,and delayed embryogenesis of T.castaneum.Further observation discovered that knockdown of TcCTL14 inhibited the development of ovaries and embryos.The detection of signaling pathways revealed that TcCTL14 may be involved in metamorphosis and fecundity by impacting 20-hydroxyecdysone and vitellogenin,respectively.Overall,these results indicate that TcCTL14 may contribute to immune response by agglutination or regulating the expression of antimicrobial peptides by the Toll/IMD pathway,and is required for T.castaneum development including metamorphosis,fecundity,and embryogenesis.These findings will improve the functional cognition of PRR CTL in insects and provide the new strategy for pest control.展开更多
文摘The C-type lectin receptors （CLRs） belong to a large family of proteins that contain a carbohydrate recognition domain （CRD） and calcium binding sites on their extracellular domains. Recent studies indicate that many CLRs, such as Dectin-1, Dectin-2 and Mincle, function as pattern recognition receptors （PRRs） recognizing carbohydrate ligands from infected microorganisms. Upon ligand binding, these CLRs induce multiple signal transduction cascades through their own immunoreceptor tyrosine-based activation motifs （ITAMs） or interacting with ITAM-containing adaptor proteins such as FcRy. Emerging evidence indicate that CLR-induced signaling cascades lead to the activation of nuclear factor kappaB （NF-KB） family of transcriptional factors through a Syk- and CARD9-dependent pathway（s）. The activation of NF-κB plays a critical role in the induction of innate immune and inflammatory responses following microbial infection and tissue damages. In this review, we will summarize the recent progress on the signal transduction pathways induced by CLRs. and how these CLRs activate NF-κB and contribute to innate immune and inflammatory responses.
基金This study was supported by the National Natural Science Foundation of China(81200477).
文摘Background:The C-type lectin receptor(CLR)expressed by DCs participates in the recognition and capture of various glycosylated self-antigens and pathogens.Understanding the diversity of the CLR expressed by DCs,as well as their role in maintaining the balance between Th1-type and Th2-type cytokines would promote the understanding of the pathogenesis of many diseases including preeclampsia(PE).Methods:DCs were isolated from the placentae of healthy women who underwent normal pregnancies and infected with a CLR lentiviral(LV)vector for gene overexpression or small interfering RNA(siRNA)knockdown.DCs were cocultured with T-cells and EVCTs,and five groups were established as follows:Group 1-DCs from healthy women who underwent normal pregnancies,Group 2-DCs from women with preeclampsia(PE),Group 3-DCs infected with empty LV vectors,Group 4-DCs infected with a CLR LV vector for gene overexpression,and Group 5-DCs infected with a CLR LV vector for siRNA knockdown.The levels of Th1-and Th2-type cytokines were measured in all groups.Results:The levels of Th1-type cytokines were significantly higher in women with PE than in those with normal pregnancies(P<0.05).Among these five groups,the Th1/Th2 ratio of Group 5 was highest(P<0.05).There was no difference in the Th1/Th2 ratio between Groups 1 and 3.Conclusions:There was a Th1/Th2 imbalance in women with PE displaying Th1-type immunity.CLR-overexpressing DCs showed a diminished capacity to polarize na?ve T-cells into Th1 effector cells.The impaired Th1 response in DCs was rescued by CLR siRNA knockdown.In conclusion,DCs may affect the production of cytokines and the migration of T-cells through CLR-mediated signaling pathways during pregnancy.
基金financially supported by the National Natural Science Foundation of China (No.32002422)the Natural Science Foundation of Shandong Province (No.ZR 2020QC212)+4 种基金the Young Experts of Taishan Scholars (No.tsqn201909130)the Shandong Technical System of Fish Industry (No. SDAIT-12-03)the Science and Technology Support Plan for Youth Innovation of Colleges and Universities in Shandong Province (No. 2019KJF003)the Breeding Plan of Shandong Provincial Qingchuang Research Team (2019)the Advanced Talents Foundation of QAU Grant (No. 663-1120023)
文摘CD209,a transmembrane lectin belonging to the C-type lectin family,can recognize carbohydrates on the surface of host cells and invading pathogens,and play an important role in cell adhesion and migration,pathogen recognition and immune activation.Although well characterized in mammals,CD209 is still under-researched in fish.Here,we report a CD209-like gene,which was named SsCD209like,in black rockfish Sebastes schlegelii,and analyzed its structure features,expression patterns and ligand-binding activities.SsCD209like displays structural similarities to mammalian CD209s,with a cytosolic tail at N-terminus,a transmembrane region and an extracellular part containing a neck region and a CRD at C-terminus.The extracellular region and the neck region of SsCD-209like can both form dimers,which is different with the tetramer in human homologue.This result demonstrates the multimerization of CD209 homologue in fish for the first time.The EPN motif,a functional motif participating in sugar binding and affinity determination,is conserved in the CRD of SsCD209like,which is consistent with the higher binding strength of this lectin to L-fucose,D-GlcNAc and D-mannose.The binding of SsCD209like to different bacteria strains and bacteria-derived pathogen associated molecular patterns(PAMPs)are also observed in a dose-dependent manner.Results in this study show the sequence and structure features of SsCD209like and demonstrate its binding properties as a pathogen recognition receptor,which promotes our understanding of CD209 homologues in fish and provides basis for more in-depth studies of this molecule in the future.
基金the project of the National Key R&D Program of China(2017YFE0122000)the National Natural Science Foundation of China(31871968)the Natural Science Foundation of Fujian Province,China(2018J01614).
文摘C-type lectins(CTLs)are a superfamily of Ca^(2+)-dependent carbohydrate-recognition proteins,and an important pattern recognition receptor(PRR)in insect innate immunity which can mediate humoral and cellular immunity in insects.In this study,we report a novel dual carbohydrate-recognition domain(CRD)CTL from Plutella xylostella which we designate PxIML.PxIML is a protein with a 969 bp open reading frame(ORF)encoding 322 amino acids,containing a signal peptide and a dual-CRD with EPN(Glu_(124)-Pro_(125)-Asn_(126))and QPD(Gln_(274)-Pro_(275)-Asp_(276))motifs.The expression of PxIML mRNA in the fat body was significantly higher than in hemocytes and midgut.The relative expression levels of PxIML in the whole insect and the fat body were significantly inhibited after infection with Bacillus thuringiensis 8010(Bt8010)at 18 h,while they were significantly upregulated after infection with Serratia marcescens IAE6 or Pichia pastoris.The recombinant PxIML(rPxIML)protein could bind to the tested pathogen-associated molecular patterns(PAMPs),and the bacteria of Enterobacter sp.IAE5,S.marcescens IAE6,Staphylococcus aureus,Escherichia coli BL21,and Bt8010 in a Ca^(2+)-dependent manner,however,it showed limited binding to the fungus,P.pastoris.The rPxIML exhibited strong activity in the presence of Ca^(2+) to agglutinate Bt8010,Enterobacter sp.IAE5 and S.aureus,but it only weakly agglutinated with E.coli BL21,and could not agglutinate with S.marcescens IAE6 or P.pastoris.Furthermore,the rPxIML could bind to hemocytes,promote the adsorption of hemocytes to beads,and enhance the phenoloxidase(PO)activity and melanization of P.xylostella.Our results suggest that PxIML plays an important role in pathogen recognition and in mediating subsequent humoral and cellular immunity of P.xylostella.
基金Supported by the National Basic Research Program of China (973 Program) (No. 2006CB101804)the National Natural Science Foundation of China (No. 30972245)Public Industry (Agriculture) Specific Research Program (No. 200803012)
文摘Acting as one of the pattern recognition receptors (PRRs), C-type lectin is believed to mediate pathogen recognition and plays an important role in the clearance of pathogens as part of the innate immune system. In this work, a novel C-type lectin gene (named LvLec1) was cloned from the shrimp Litopenaeus vannamei. The ORF of LvLec1 is 510 bp, encoding 169 amino acids. The deduced amino acid sequence contains a putative signal peptide of 19 amino acids at the N-terminal and a carbohydrate recognition domain (CRD) at the C-terminal. LvLec1 was mainly expressed in the hepatopancreas. Real-time PCR analysis indicated that the level of LvLec1 transcripts significantly changed in the hepatopancreas after the shrimp were artificially challenged with LPS, Micrococcus lysodeikticus and white spot syndrome virus (WSSV). RNAi-based silencing of LvLec1 resulted in increases in mortality when the shrimp were challenged with WSSV, and the median lethal time was reduced compared with controls. Although there was no characteristic "EPN" (Glu-Pro-Ser) or "QPD" (Gln-Pro-Asp) motif, the recombinant LvLec1, expressed in Escherichia coli BL21 (DE3), could also agglutinate M. lysodeikticus and Vibrio anguillarum. The agglutinating activities were calcium-dependent and could be inhibited by D-mannose, D-glucose, D-galactose and N-Acetyl-D-mannose. These results suggest that LvLec1 might be involved in the immune response against WSSV and bacterial infections and contribute to non-self recognition as a pattern recognition receptor in the innate immune system of the shrimp L. vannamei.
基金The National High-Technology R&D Program(863 Program) of China under contract No.2012AA10A409China Agriculture Research System under contract No.CARS-47
文摘C-type lectins are among the most significant pattern recognition receptors（PRRs） found in invertebrate. They are a class of carbohydrate-binding proteins that can recognize specific sugar moieties on the surface of pathogens. In the present study, a novel C-type lecitn（termed Mj Lectin） from kuruma shrimp Marsupenaeus japonicus was identified. The full-length c DNA of Mj Lectin was 1 245 bp with a 1 011 bp open reading frame（ORF） that encoded a polypeptide of 336 amino acid residues. Mj Lectin consisted of two tandemly arrayed carbohydrate-recognition domains（CRDs）, unlike other reported M. japonicus C-type lectins with only one CRD. It showed a high similarity to other shrimp dual-CRD lectins. Among the Ca2＋-binding Site 2, the tripeptide motif dictating the carbohydrate binding specificity was exhibited as a rare mutant LPN（Leu134-Pro135-Asn136） in CRD1 and a traditional EPN（Glu299-Pro300-Asn301） in CRD2, respectively. Mj Lectin showed a specific expression pattern in both tissue and cellular levels, for its m RNA transcript was mainly expressed in the F-cells of the hepatopancreas. After white spot syndrome virus（WSSV） challenge（3.6×108 virions/μL）, the expression of Mj Lectin in the hepatopancreas was up-regulated significantly at 48 h（P〈0.01） compared with the control group. These results suggested that Mj Lectin might be involved in the innate immune defense against WSSV infection.
文摘Ten cases of gastrointestinal adenocarcinomas were histochemically investigated fortheir lectin receptors by avidin—biotin-peroxidase complex(ABC)method.Results showed thatgastric adenocarcinomas expressed more types of lectin receptors than large boweladenocarcinomas.Positive rates of Glc/Man-and GlcNAc-specific lectin receptors in these tu-mors were kigher than those of Gal/GalNAc-and Fuc-specific lectin receptors.From the stom-ach to rectum,the spectrum of the lectin receptors in pericarcinomatous tissues graduallychanged from the gastric type to the rectal type.The expression of lectin receptors ingustrointestinal adenocarcinomas was obviously different Jrom that in their correspondingpericarcinomatous tissues.The increase and decrease of lectin receptor expression,theappearance and disappearance of some types of lectin receptors as well as the change of thereceptor distribution are indirectly regulated by cellular genome.
基金Supported by the National Natural Science Foundation of China(No.31702375)the Fundamental Research Funds of Zhejiang Sci-Tech University(No.2019Q047)。
文摘As an important pattern recognition receptor(PRR)in the innate immune system,C-type lectin plays an important role in the innate immune process of invertebrates.Two C-type lectins Sp CTL-C and Sp CTL-D were characterized from mud crab(Scylla paramamosain).The predicted Sp CTL-C and Sp CTL-D proteins both contain a single carbohydrate-recognition domain(CRD)with key motif Gln-Pro-Ala(QPA)and Met-Pro-Ala(MPA),respectively.Sp CTL-C and Sp CTL-D transcripts distributed in all examined tissues,and the expression level was the highest in hepatopancreas.As PRR,the purifi ed recombinant proteins r Sp CTL-C and r Sp CTL-D have high affi nity for three kinds of pathogen-associated molecular patterns(PAMPs):β-glucan,lipopolysaccharide,and peptidoglycan.Besides,r Sp CTL-D can bind to all nine microorganisms tested,while r Sp CTL-C can bind to seven microorganisms except for Staphylococcus aureus and Micrococcus luteus.Both r Sp CTL-C and r Sp CTL-D showed agglutination activity towards fungi Pichia pastoris and Saccharomyces cerevisiae.However,r Sp CTL-C and r Sp CTL-D exhibited diff erent antimicrobial activities:r Sp CTL-D has a certain inhibitory eff ect on the growth of Vibrio fl uvialis and M.luteus,while r Sp CTL-C has no obvious inhibitory activity.The results show that r Sp CTL-C and r Sp CTL-D had better phagocytosis-promoting eff ect on M.luteus than the negative control.Meanwhile,both r Sp CTL-C and r Sp CTL-D had certain encapsulation-promoting activity.Collectively,two C-type lectins with novel key motifs make an important impact as PRR in immune response towards pathogens.At the same time,they play diff erent functions in the innate immunity of mud crab S.paramamosain.
文摘The C-type lectin MGL is a pathogen recognition receptor, expressed by dendritic cells (DCs) and macrophages (Mfs), able to bind GalNAc (Tn) carrying structures. This receptor also recognized Tn-TAAs that were internalized, processed and presented by DCs to T cells and it acted as an adjuvant on DCs, highlighting its possible application in anti-cancer vaccination. In this work, we found that this receptor present a seasonal modulation: its expression is higher in winter rather than in summer. The percentage of MGL+ donors displayed a negative trend that dropped to 33% during the summer and increased up to 100% in winter. This modulation could be also ascribed to the circa-annual variation of glucocorticoids, in fact MGL is up-regulated in presence of dexamethasone in vitro. The seasonal variation of this receptor could be an important point in the field of tumor vaccination strategies.
文摘Eight lectins were used to study 100 cases of breast carcinoma and 56 cases of non-carcinoma breast tissues by lectin affinity histochemical method. The results showed that Bandeirasa Simplicifolia (BSL) and Peanut agglutinin (PNA) had higher positive rates in breast carcinoma than both normal breast and benign lesions (P<0.005). The positive deposit in malignant lesions was mainly located in cytoplasm, while in non-malignant lesions, it was almost lined along the lumen of glands and small ducts (P<0.005). The authors think that expression of PNA-receptor in the cytoplasm might be associated with the mechanism that the tumor could escape from immune attack. Comparison analysis on the normal breast indicated that PNA affinity histoche-mistry would be useful to the understanding of the metabolism of β-D-galactosyl-N-acetyl-D-galactosa-mine during the development of normal breast and histological origin of breast carcinoma.
基金Scientific research project of Hainan Provincial Department of Education(No.hnky2018zd-7)。
文摘Pattern recognition receptor(PRR)is a kind of sensor which is mainly expressed on the surface of innate immune cells.It can recognize pathogen related molecular patterns(PAMPs)or damage related molecular patterns(DAMPs).The innate immune system uses pattern recognition receptors to recognize pathogenic microorganisms in periodontal tissues and transmit signals to downstream pathways in time,thus triggering immune responses and then eliminating them.PRR has many family members,including toll like receptor family(TLRs),C-type lectin receptor family(CLRs),retinoic acid induced gene I(RIG-I)like receptor family(RLRs)and nucleotide binding oligomer domain(NOD)like receptor family(NLRs).Among them,RLRs are cytoplasmic receptors that recognize dsRNA from RNA viruses and have little association with chronic periodontitis.In this paper,the classification and structure of TLRs,CLRs,NLRs and the role of signal transduction pathway in chronic periodontitis are reviewed.In order to enrich the pathogenesis of periodontitis,provide new ideas for the treatment and prevention of chronic periodontitis.
基金supported by grants from the National Natural Science Foundation of China to Bin Li(Grant number:31872970 and 32170521).
文摘Evidence is accumulating that pattern recognition receptor(PRR)C-type lectins(CTL)play essential roles in recognition of pathogens.TcCTL14(accession no.TC00871)contains the most domains among all CTL of Tribolium castaneum.Yet the biological function of TcCTL14 remains unclear.In this study,TcCTL14 exhibiting typical motif and domain of CTL was cloned from T.castaneum.The expression pattern analysis showed that TcCTL14 was highly expressed in late pupae and central nervous system,and was upregulated after treatment with Escherichia coli and Staphylococcus aureus,respectively.Analysis of binding affinity revealed that recombinant TcCTL14 not only could bind to lipopolysaccharide and peptidoglycan in a dose-dependent fashion,but possibly could bind to and agglutinate different bacteria in a Ca^(2+)-dependent fashion.Knockdown of TcCTL14 before injection with bacteria led to the downregulation of nuclear factor-κB transcription factors of Toll/IMD and 4 antimicrobial peptides.Knockdown of TcCTL14 also caused suppressed metamorphosis,reduced fecundity,and delayed embryogenesis of T.castaneum.Further observation discovered that knockdown of TcCTL14 inhibited the development of ovaries and embryos.The detection of signaling pathways revealed that TcCTL14 may be involved in metamorphosis and fecundity by impacting 20-hydroxyecdysone and vitellogenin,respectively.Overall,these results indicate that TcCTL14 may contribute to immune response by agglutination or regulating the expression of antimicrobial peptides by the Toll/IMD pathway,and is required for T.castaneum development including metamorphosis,fecundity,and embryogenesis.These findings will improve the functional cognition of PRR CTL in insects and provide the new strategy for pest control.
