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
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 ...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 LvLecl) was cloned from the shrimp Litopenaeus vannamei, The ORF of LvLecl 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. LvLecl was mainly expressed in the hepatopancreas. Real-time PCR analysis indicated that the level of LvLecl 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 LvLecl 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" (Gin-Pro-Asp) motif, the recombinant LvLecl, 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 LvLecl 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(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
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
Here we report a family with a clinical spectrum of Pachyonychia Congenita Tarda (PCT) encompassing two generations via a balanced chromosomal translocation between 4q26 and 12p12.3. We discuss the effects of chromoso...Here we report a family with a clinical spectrum of Pachyonychia Congenita Tarda (PCT) encompassing two generations via a balanced chromosomal translocation between 4q26 and 12p12.3. We discuss the effects of chromosomal translocations on gene expression through involved breakpoints and structural gene abnormalities detected by array CGH. We believe that the family we present gives further insight to the better understanding of molecular and structural basis of keratin disorders, and to the late onset and genetic basis of PCT through the possible role of C-type lectins and human epithelial membrane protein1 (EMP1). Better understanding of the molecular basis of keratin disorders is the foundation for improved diagnosis, genetic counseling and novel therapeutic approaches to overcome the current treatment limitations related to this disease.展开更多
C-type lectins(CTLs)are a family of proteins that contain 1 or more carbohydrate-recognition domains(CRDs)and bind to a broad repertoire of ligands in the presence of calcium ions.CTLs play important roles in innate i...C-type lectins(CTLs)are a family of proteins that contain 1 or more carbohydrate-recognition domains(CRDs)and bind to a broad repertoire of ligands in the presence of calcium ions.CTLs play important roles in innate immune defenses against microorganisms by acting as pattern-recognition receptors(PRRs)for invading pathogens,such as bacteria,viruses,and parasites.After binding to pathogen-associated ligands,CTLs mediate immune responses,such as agglutination,phagocytosis,and the activation of phenol oxidase progenitors,thereby clearing pathogens.CTLs are an evolutionarily conserved family found in almost all vertebrates and invertebrates.Medical arthropods can acquire and transmit a range pathogens through various approaches,such as bloodsucking,lancing,and parasitism,thus infecting humans and animals with related diseases,some of which can be life-threatening.Recent studies have shown that lectins are important components of the arthropod immune system and are essential for the immune responses of arthropods to arthropod-borne pathogens.This article reviews the current understanding of the structure,function,and signaling pathways involved in CTLs derived from important medical arthropods.展开更多
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
C-type lectin receptors(CLRs)are powerful pattern-recognition receptors that discern‘self’and‘non-self’in our body and protect us from invasive pathogens by mediating immune recognition and response.The gastrointe...C-type lectin receptors(CLRs)are powerful pattern-recognition receptors that discern‘self’and‘non-self’in our body and protect us from invasive pathogens by mediating immune recognition and response.The gastrointestinal tract is very important for the maintenance of homeostasis;it is the largest shelter for the billions of microorganisms in the body and CLRs play a crucial regulatory role in this system.This study focuses on several CLRs,including Dectin-1,Dectin-2,Dectin-3 and Mincle.We summarize the roles of CLRs in maintaining gastrointestinal immune-system homeostasis,especially their functions in mediating immune recognition and responses in the gut,discuss their relationships to some diseases,highlight the significance of CLR-mediated sensing of microbial and non-microbial compounds in the gut immune system and identify new therapeutic targets.展开更多
C-type lectins(CTLs)represent a large family of soluble and membrane-bound proteins which bind calcium dependently via carbohydrate recognition domains(CRDs)to glycan residues presented on the surface of a variety of ...C-type lectins(CTLs)represent a large family of soluble and membrane-bound proteins which bind calcium dependently via carbohydrate recognition domains(CRDs)to glycan residues presented on the surface of a variety of pathogens.The deconvolution of a cell’s glycan code by CTLs underpins several important physiological processes in mammals such as pathogen neutralization and opsonization,leukocyte trafficking,and the inflammatory response.However,as our knowledge of CTLs has developed it has become apparent that the role of this innate immune family of proteins can be double-edged,where some pathogens have developed approaches to subvert and exploit CTL interactions to promote infection and sustain the pathological state.Equally,CTL interactions with host glycoproteins can contribute to inflammatory diseases such as arthritis and cancer whereby,in certain contexts,they exacerbate inflammation and drive malignant progression.This review discusses the‘dual agent’roles of some of the major mammalian CTLs in both resolving and promoting infection,inflammation and inflammatory disease and highlights opportunities and emerging approaches for their therapeutic modulation.展开更多
Background Macrophage-inducible C-type lectin (MINCLE) is an important member of C-type lectin superfamily, which has been shown evidence for susceptibility to arthritis in animal models. We aimed to investigate the...Background Macrophage-inducible C-type lectin (MINCLE) is an important member of C-type lectin superfamily, which has been shown evidence for susceptibility to arthritis in animal models. We aimed to investigate the possible association of MINCLE with rheumatoid arthritis (RA) susceptibility in Chinese Han population. Methods Haplotypes from HapMap database (Chinese Han Beijing, CHB) were used to select tag-single nucleotide polymorphism (SNP) (r2=0.8) residing in MINCLE gene. A total of 563 patients with RA and 404 healthy controls were TagMan genotyped for SNP rs10841845. Association analyses were performed on the whole data set and on RA subsets based on gender difference and the status of anti-cyclic citrullinated peptide (anti-CCP) antibody in RA patients. Association statistics were calculated by age and sex adjusted logistic regression. Results Overall, MINCLE SNP rs10841845 was not associated with susceptibility to RA. However, following anti-CCP stratification, rs10841845 GG genotypes conferred a significantly protective effects against anti-CCP-positive RA (OR 0.65, 95% CI 0.430-0.995, P=0.048). Following gender stratification, SNP rs10841845 G allele appeared to insert its RA protective effect only in male patients, both at allele level (G vs. A OR 0.66, 95% CI 0.46-0.93, P=0.018) and at genotype level (GG vs. AA±AG, OR 0.429, 95% CI 0.20-0.95, P=0.036). Notably, the male RA protective effect of rs10841845 G allele was only seen in anti-CCP-positive RA (G vs. A: OR 0.64, 95% CI 0.43-0.96, P=0.029; GG vs. AA+AG: OR 0.375, 95% CI 0.14-0.94, P=0.038). Furthermore, we observed a significant reduction of Disease Activity Score (DAS) 28 score (3.91±0.70 vs. 5.66±0.31, P=-0.022) and serum C-reactive protein levels (31.64±24.13 vs. 91.80±12.02, P=0.012) in male anti-CCP-positive RA patients carrying rs10841845 GG genotype, compared with patients carrying AA±AG genotypes. Conclusions Our study provides the evidence for a gender specific association between MINCLE rs10841845 and RA susceptibility. The SNP rs10841845 G allele appears to have protective effect against anti-CCP-positive RA and confer reduced RA activity in men.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
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 naïve 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
Insects have a large family of C-type lectins involved in cell adhesion, pathogen recognition and activation of immune responses. In this study, 32 transcripts encoding C-type lectin domain proteins (CTLDPs) were iden...Insects have a large family of C-type lectins involved in cell adhesion, pathogen recognition and activation of immune responses. In this study, 32 transcripts encoding C-type lectin domain proteins (CTLDPs) were identified from the Thitarodes xiaojinensis transcriptome. According to their domain structures, six CTLDPs with one carbohydraterecognition domain (CRD) were classified into the CTL-S subfamily. The other 23 CTLDPs with two CRDs were grouped into the immulectin (IML) subfamily. The remaining three with extra regulatory domains were sorted into the CTL-X subfamily. Phylogenetic analysis showed that CTL-S and CTL-X members from different insects could form orthologous groups. In contrast, no T. xiaojinensis IML orthologues were found in other insects. Remarkable lineage-specific expansion in this subfamily was observed reflecting that these CTLDPs, as important receptors, have evolved diversified members in response to a variety of microbes. Prediction of binding ligands revealed that T. xiaojinensis, a coldadapted species, conserved the ability of CRDs to combine with Ca^2+ to keep its receptors from freezing. Comparative analysis of induction of CTLDP genes after different immune challenges indicated that IMLs might play critical roles in immune defenses. This study examined T. xiaojinensis CTLDPs and provides a basis for further studies of their characteristics.展开更多
Accumulating evidence suggests that C-type lectin-like receptor-2(CLEC-2)plays an important role in atherothrombosis.In this case-control study,we investigated the association between CLEC-2 and incidence of coronary ...Accumulating evidence suggests that C-type lectin-like receptor-2(CLEC-2)plays an important role in atherothrombosis.In this case-control study,we investigated the association between CLEC-2 and incidence of coronary artery disease(CAD).A total of 216 patients,including 14 cases of stable angina pectoris(SAP,non-ACS)and 202 cases of acute coronary syndrome(ACS),and 89 non-CAD control subjects were enrolled.Plasma levels of soluble CLEC-2(sCLEC-2)were measured using the enzyme-linked immunosorbent assay(ELISA).Compared with the control group(65.69(55.36–143.22)pg/mL),the plasma levels of sCLEC-2 were significantly increased in patients with CAD(133.67(88.76–220.09)pg/mL)and ACS(134.16(88.88–225.81)pg/mL).The multivariate adjusted odds ratios(95%confidence interval)of CAD reached 2.01(1.52–2.66)(Ptrend<0.001)for each 1-quartile increase in sCLEC-2.Restricted cubic splines showed a positive dose-response association between sCLEC2 and CAD incidence(Plinearity<0.001).The addition of sCLEC-2 to conventional risk factors improved the C statistic(0.821 vs.0.761,P=0.004)and reclassification ability(net reclassification improvement:57.45%,P<0.001;integrated discrimination improvement:8.27%,P<0.001)for CAD.In conclusion,high plasma sCLEC-2 is independently associated with CAD risk,and the prognostic value of sCLEC-2 may be evaluated in future prospective studies.展开更多
Objective Recombinase-aided polymerase chain reaction(RAP)is a sensitive,single-tube,two-stage nucleic acid amplification method.This study aimed to develop an assay that can be used for the early diagnosis of three t...Objective Recombinase-aided polymerase chain reaction(RAP)is a sensitive,single-tube,two-stage nucleic acid amplification method.This study aimed to develop an assay that can be used for the early diagnosis of three types of bacteremia caused by Staphylococcus aureus(SA),Pseudomonas aeruginosa(PA),and Acinetobacter baumannii(AB)in the bloodstream based on recombinant human mannanbinding lectin protein(M1 protein)-conjugated magnetic bead(M1 bead)enrichment of pathogens combined with RAP.Methods Recombinant plasmids were used to evaluate the assay sensitivity.Common blood influenza bacteria were used for the specific detection.Simulated and clinical plasma samples were enriched with M1 beads and then subjected to multiple recombinase-aided PCR(M-RAP)and quantitative PCR(qPCR)assays.Kappa analysis was used to evaluate the consistency between the two assays.Results The M-RAP method had sensitivity rates of 1,10,and 1 copies/μL for the detection of SA,PA,and AB plasmids,respectively,without cross-reaction to other bacterial species.The M-RAP assay obtained results for<10 CFU/mL pathogens in the blood within 4 h,with higher sensitivity than qPCR.M-RAP and qPCR for SA,PA,and AB yielded Kappa values of 0.839,0.815,and 0.856,respectively(P<0.05).Conclusion An M-RAP assay for SA,PA,and AB in blood samples utilizing M1 bead enrichment has been developed and can be potentially used for the early detection of bacteremia.展开更多
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.
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 LvLecl) was cloned from the shrimp Litopenaeus vannamei, The ORF of LvLecl 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. LvLecl was mainly expressed in the hepatopancreas. Real-time PCR analysis indicated that the level of LvLecl 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 LvLecl 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" (Gin-Pro-Asp) motif, the recombinant LvLecl, 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 LvLecl 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 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 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Here we report a family with a clinical spectrum of Pachyonychia Congenita Tarda (PCT) encompassing two generations via a balanced chromosomal translocation between 4q26 and 12p12.3. We discuss the effects of chromosomal translocations on gene expression through involved breakpoints and structural gene abnormalities detected by array CGH. We believe that the family we present gives further insight to the better understanding of molecular and structural basis of keratin disorders, and to the late onset and genetic basis of PCT through the possible role of C-type lectins and human epithelial membrane protein1 (EMP1). Better understanding of the molecular basis of keratin disorders is the foundation for improved diagnosis, genetic counseling and novel therapeutic approaches to overcome the current treatment limitations related to this disease.
基金supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions,National Natural Science Foundation of China(81271792,81471571,81971917,and 32170142)Jiangsu Natural Science Foundation(BK20211310).
文摘C-type lectins(CTLs)are a family of proteins that contain 1 or more carbohydrate-recognition domains(CRDs)and bind to a broad repertoire of ligands in the presence of calcium ions.CTLs play important roles in innate immune defenses against microorganisms by acting as pattern-recognition receptors(PRRs)for invading pathogens,such as bacteria,viruses,and parasites.After binding to pathogen-associated ligands,CTLs mediate immune responses,such as agglutination,phagocytosis,and the activation of phenol oxidase progenitors,thereby clearing pathogens.CTLs are an evolutionarily conserved family found in almost all vertebrates and invertebrates.Medical arthropods can acquire and transmit a range pathogens through various approaches,such as bloodsucking,lancing,and parasitism,thus infecting humans and animals with related diseases,some of which can be life-threatening.Recent studies have shown that lectins are important components of the arthropod immune system and are essential for the immune responses of arthropods to arthropod-borne pathogens.This article reviews the current understanding of the structure,function,and signaling pathways involved in CTLs derived from important medical arthropods.
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 work is supported by grants from the National Natural Science Foundation of China(81572354 and 81772542 to T.W.)the Natural Science Foundation of Jiangsu Province in China(BK20161400 to T.W.).
文摘C-type lectin receptors(CLRs)are powerful pattern-recognition receptors that discern‘self’and‘non-self’in our body and protect us from invasive pathogens by mediating immune recognition and response.The gastrointestinal tract is very important for the maintenance of homeostasis;it is the largest shelter for the billions of microorganisms in the body and CLRs play a crucial regulatory role in this system.This study focuses on several CLRs,including Dectin-1,Dectin-2,Dectin-3 and Mincle.We summarize the roles of CLRs in maintaining gastrointestinal immune-system homeostasis,especially their functions in mediating immune recognition and responses in the gut,discuss their relationships to some diseases,highlight the significance of CLR-mediated sensing of microbial and non-microbial compounds in the gut immune system and identify new therapeutic targets.
基金D.A.M.is supported by the Howard Ostin Fund and the University Hospitals Coventry and Warwickshire Renal Medicine Department.J.N.A.is funded by a grant from Cancer Research UK(DCRPGF\100009)and is the recipient of a Cancer Research Institute/Wade F.B.Thompson CLIP grant(CRI3645).
文摘C-type lectins(CTLs)represent a large family of soluble and membrane-bound proteins which bind calcium dependently via carbohydrate recognition domains(CRDs)to glycan residues presented on the surface of a variety of pathogens.The deconvolution of a cell’s glycan code by CTLs underpins several important physiological processes in mammals such as pathogen neutralization and opsonization,leukocyte trafficking,and the inflammatory response.However,as our knowledge of CTLs has developed it has become apparent that the role of this innate immune family of proteins can be double-edged,where some pathogens have developed approaches to subvert and exploit CTL interactions to promote infection and sustain the pathological state.Equally,CTL interactions with host glycoproteins can contribute to inflammatory diseases such as arthritis and cancer whereby,in certain contexts,they exacerbate inflammation and drive malignant progression.This review discusses the‘dual agent’roles of some of the major mammalian CTLs in both resolving and promoting infection,inflammation and inflammatory disease and highlights opportunities and emerging approaches for their therapeutic modulation.
文摘Background Macrophage-inducible C-type lectin (MINCLE) is an important member of C-type lectin superfamily, which has been shown evidence for susceptibility to arthritis in animal models. We aimed to investigate the possible association of MINCLE with rheumatoid arthritis (RA) susceptibility in Chinese Han population. Methods Haplotypes from HapMap database (Chinese Han Beijing, CHB) were used to select tag-single nucleotide polymorphism (SNP) (r2=0.8) residing in MINCLE gene. A total of 563 patients with RA and 404 healthy controls were TagMan genotyped for SNP rs10841845. Association analyses were performed on the whole data set and on RA subsets based on gender difference and the status of anti-cyclic citrullinated peptide (anti-CCP) antibody in RA patients. Association statistics were calculated by age and sex adjusted logistic regression. Results Overall, MINCLE SNP rs10841845 was not associated with susceptibility to RA. However, following anti-CCP stratification, rs10841845 GG genotypes conferred a significantly protective effects against anti-CCP-positive RA (OR 0.65, 95% CI 0.430-0.995, P=0.048). Following gender stratification, SNP rs10841845 G allele appeared to insert its RA protective effect only in male patients, both at allele level (G vs. A OR 0.66, 95% CI 0.46-0.93, P=0.018) and at genotype level (GG vs. AA±AG, OR 0.429, 95% CI 0.20-0.95, P=0.036). Notably, the male RA protective effect of rs10841845 G allele was only seen in anti-CCP-positive RA (G vs. A: OR 0.64, 95% CI 0.43-0.96, P=0.029; GG vs. AA+AG: OR 0.375, 95% CI 0.14-0.94, P=0.038). Furthermore, we observed a significant reduction of Disease Activity Score (DAS) 28 score (3.91±0.70 vs. 5.66±0.31, P=-0.022) and serum C-reactive protein levels (31.64±24.13 vs. 91.80±12.02, P=0.012) in male anti-CCP-positive RA patients carrying rs10841845 GG genotype, compared with patients carrying AA±AG genotypes. Conclusions Our study provides the evidence for a gender specific association between MINCLE rs10841845 and RA susceptibility. The SNP rs10841845 G allele appears to have protective effect against anti-CCP-positive RA and confer reduced RA activity in men.
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.
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 naïve 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National Key Plan for Scientific Research and Development of China (2017YFD0200400, 2016YFC1200603)National Natural Science Foundation of China (No. 31272366, 30900947, 31672291)Open research Fund Program of State Key Laboratory of Integrated Pest Management (Chinese IPM1505, 1612).
文摘Insects have a large family of C-type lectins involved in cell adhesion, pathogen recognition and activation of immune responses. In this study, 32 transcripts encoding C-type lectin domain proteins (CTLDPs) were identified from the Thitarodes xiaojinensis transcriptome. According to their domain structures, six CTLDPs with one carbohydraterecognition domain (CRD) were classified into the CTL-S subfamily. The other 23 CTLDPs with two CRDs were grouped into the immulectin (IML) subfamily. The remaining three with extra regulatory domains were sorted into the CTL-X subfamily. Phylogenetic analysis showed that CTL-S and CTL-X members from different insects could form orthologous groups. In contrast, no T. xiaojinensis IML orthologues were found in other insects. Remarkable lineage-specific expansion in this subfamily was observed reflecting that these CTLDPs, as important receptors, have evolved diversified members in response to a variety of microbes. Prediction of binding ligands revealed that T. xiaojinensis, a coldadapted species, conserved the ability of CRDs to combine with Ca^2+ to keep its receptors from freezing. Comparative analysis of induction of CTLDP genes after different immune challenges indicated that IMLs might play critical roles in immune defenses. This study examined T. xiaojinensis CTLDPs and provides a basis for further studies of their characteristics.
基金supported by grants from the National Natural Science Foundation of China(Nos.81870325,81620108001,and 91739302 to Li Zhu)the Priority Academic Program Development of Jiangsu Higher Education Institutions of China and Suzhou Key laboratory of Thrombosis and Vascular Diseases(to Li Zhu)+1 种基金the Suzhou Science and Technology Project Foundation(No.SYS201721 to Li Xiang)the Young Investigator Pre-research Foundation of the Second Affiliated Hospital of Soochow University(No.SDFEYQN1717 to Tao You).
文摘Accumulating evidence suggests that C-type lectin-like receptor-2(CLEC-2)plays an important role in atherothrombosis.In this case-control study,we investigated the association between CLEC-2 and incidence of coronary artery disease(CAD).A total of 216 patients,including 14 cases of stable angina pectoris(SAP,non-ACS)and 202 cases of acute coronary syndrome(ACS),and 89 non-CAD control subjects were enrolled.Plasma levels of soluble CLEC-2(sCLEC-2)were measured using the enzyme-linked immunosorbent assay(ELISA).Compared with the control group(65.69(55.36–143.22)pg/mL),the plasma levels of sCLEC-2 were significantly increased in patients with CAD(133.67(88.76–220.09)pg/mL)and ACS(134.16(88.88–225.81)pg/mL).The multivariate adjusted odds ratios(95%confidence interval)of CAD reached 2.01(1.52–2.66)(Ptrend<0.001)for each 1-quartile increase in sCLEC-2.Restricted cubic splines showed a positive dose-response association between sCLEC2 and CAD incidence(Plinearity<0.001).The addition of sCLEC-2 to conventional risk factors improved the C statistic(0.821 vs.0.761,P=0.004)and reclassification ability(net reclassification improvement:57.45%,P<0.001;integrated discrimination improvement:8.27%,P<0.001)for CAD.In conclusion,high plasma sCLEC-2 is independently associated with CAD risk,and the prognostic value of sCLEC-2 may be evaluated in future prospective studies.
基金funded by the National Key R&D Program of China[2021YFC2301102]National Natural Science Foundation of China[82202593]Key R&D Program of Hebei Province[223777100D].
文摘Objective Recombinase-aided polymerase chain reaction(RAP)is a sensitive,single-tube,two-stage nucleic acid amplification method.This study aimed to develop an assay that can be used for the early diagnosis of three types of bacteremia caused by Staphylococcus aureus(SA),Pseudomonas aeruginosa(PA),and Acinetobacter baumannii(AB)in the bloodstream based on recombinant human mannanbinding lectin protein(M1 protein)-conjugated magnetic bead(M1 bead)enrichment of pathogens combined with RAP.Methods Recombinant plasmids were used to evaluate the assay sensitivity.Common blood influenza bacteria were used for the specific detection.Simulated and clinical plasma samples were enriched with M1 beads and then subjected to multiple recombinase-aided PCR(M-RAP)and quantitative PCR(qPCR)assays.Kappa analysis was used to evaluate the consistency between the two assays.Results The M-RAP method had sensitivity rates of 1,10,and 1 copies/μL for the detection of SA,PA,and AB plasmids,respectively,without cross-reaction to other bacterial species.The M-RAP assay obtained results for<10 CFU/mL pathogens in the blood within 4 h,with higher sensitivity than qPCR.M-RAP and qPCR for SA,PA,and AB yielded Kappa values of 0.839,0.815,and 0.856,respectively(P<0.05).Conclusion An M-RAP assay for SA,PA,and AB in blood samples utilizing M1 bead enrichment has been developed and can be potentially used for the early detection of bacteremia.