Vía de las lectinas, una ruta del complemento en construcción / Lectin pathway, a complement route under construction

ntroducción: El sistema del complemento puede ser activado por tres vías: clásica, alternativa y de las lectinas, esta última en fase de estudio para su completamiento. Objetivo: Describir hasta donde se ha avanzado en la construcción de la vía de las lectinas, sus iniciadores, activadores, reguladores, cascada enzimática y sus funciones biológicas. Metodología: Se realizó una revisión sobre el tema en estudio empleando artículos de libre acceso en la base de datos Pubmed y los trabajos publicados por el grupo de trabajo de la Universidad de Goettigen, la Universidad de Aarhus en Dinamarca y el Laboratorio Central de Líquido Cefalorraquídeo (LABCEL) de la Universidad de Ciencias Médicas de La Habana en los últimos cinco años comprendidos en el período de enero de 2012 a marzo del 2017. Desarrollo: Los iniciadores de la vía de las lectinas son las moléculas de reconocimiento colectinas y ficolinas circulantes en sangre, que participan en muchos procesos del organismo. Los activadores de esta vía son las MASP 1, 2 presentes como proenzimas; y la MASP 3, MAp 19 y 44 actúan como reguladoras. La cascada enzimática luego del reconocimiento es similar a la ruta clásica. Conclusiones: Las colectinas y ficolinas inician la vía de las lectinas. Sus activadores son las MASP 1, 2. Los reguladores son la MASP-3, y las MAp 19 y 44. Similar a la clásica en su cascada enzimática. Es la más antigua en la filogenia por eso participa en muchos procesos en el organismo(AU)

Introduction. The complement system can be activated in three ways: classical, alternative and lectins, the latter in the study phase for its completion. Objective. To describe the progress made in the construction of the lectin pathway, its initiators, activators, regulators, enzymatic cascade and its biological functions. Methods. A review was made on the subject under study using articles of free access in the Pubmed database and the works published by the working group of the University of Goettigen, the University of Aarhus in Denmark and the Central Laboratory of Cefalorraquìdeo liquid (LABCEL) of the University of Medical Sciences of Havana in the last five years included in the period from January 2012 to March 2017. Development. The initiators of the lectin pathway are the collectin recognition molecules and circulating ficolins in blood, which participate in many processes of the organism. The activators of this pathway are MASP 1, 2 present as proenzymes; and MASP 3, MAp 19 and 44 act as regulators. The enzymatic cascade after recognition is similar to the classical route. Conclusions. Collectins and ficolines initiate the lectin pathway. Its activators are MASP 1, 2. The regulators are MASP-3, and MAp 19 and 44. Similar to the classic in its enzymatic cascade. It is the oldest in phylogeny so it participates in many processes in the body.(AU)

An overview of the synergy and crosstalk between pentraxins and collectins/ficolins: their functional relevance in complement activation

The complement system is an innate immune defense machinery comprising components that deploy rapid immune responses and provide efficient protection against foreign invaders and unwanted host elements. The complement system is activated upon recognition of pathogenic microorganisms or altered self-cells by exclusive pattern recognition molecules (PRMs), such as collectins, ficolins and pentraxins. Recent accumulating evidence shows that the different classes of effector PRMs build up a co-operative network and exert synergistic effects on complement activation. In this review, we describe our updated view of the crosstalk between previously unlinked PRMs in complement activation and the potential pathogenic effects during infection and inflammation.

Galectins and collectinis expression are increased in Haemonchus contortus-infected corriedale sheep / Aumento da expressão gênica de colectinas e galectinas em ovinos corriedale infectados por Haemonchus contortus

Galectins and collectins are proteins classified in the lectin family that have the ability to recognize molecular patterns associated with pathogens. Studies on cattle have demonstrated high expression of these proteins during infection with gastrointestinal nematodes. The aim of this study was to investigate whether the level of Haemonchus contortus infection would alter the expression of galectins (Gal11 and Gal14) and collectins (SPA and CGN) in sheep. Twelve Corriedale sheep exposed to natural infection with nematodes were divided into two groups: group 1 (G1, n = 7) and group 2 (G2, n = 5), with low and high parasite burdens, respectively, based on fecal egg counts and abomasal parasite counts. The fecal egg counts and abomasal parasite counts were significantly different (p < 0.05) between the groups. Galectin and collectin gene expression was observed in all sheep abomasal samples. However, animals with lower infection levels showed lower expression of the genes Gal14, SPA and CGN (p < 0.05). Expression of lectins was associated with the abomasal H. contortus burden, thus suggesting that these proteins may have a role in controlling of this infection.

Colectinas e galectinas são proteínas da família das lectinas que possuem a capacidade de reconhecer padrões moleculares associados aos patógenos. Estudos em bovinos têm demonstrado a alta expressão dessas proteínas durante a infecção por nematoides gastrintestinais. O objetivo deste estudo foi investigar se o nível de infecção de Haemonchus contortus altera a expressão de colectinas (SPA e CGN) e galectinas (Gal11 e Gal14) de ovinos. Doze ovinos da raça Corriedale expostos a infecção natural com nematoides foram separados em dois grupos: grupo 1 (G1, n=7) com menor grau de parasitismo; e grupo 2 (G2, n=5) com maior grau, a partir da contagem do número de parasitos recuperados do abomaso e OPG. A contagem de OPG e de parasitos recuperados do abomaso dos grupos G1 e G2 apresentaram diferença estatística (p<0,05). A expressão dos genes de colectinas e galectina foi observada em todas as amostras de abomaso dos ovinos, porém animais com menor grau de infecção apresentaram menor expressão dos genes de Gal14, SPA e CGN (p<0,05). A expressão de lectinas foi associada ao número de H. contortus encontrados no abomaso de ovinos, indicando um possível papel dessas proteínas no controle da infecção.

Increased serum surfactant protein-D in the infants with acute respiratory syncytial virus bronchiolitis

PURPOSE: Collectin family is an important component of innate immunity, of which surfactant protein (SP)-D and mannose-binding lectin (MBL) are the most characterized. We examined SP-D and MBL in young children with acute respiratory syncytial virus (RSV) bronchiolitis. METHODS: Sixty-three children (7 days of hospital stay. All children were evaluated if they had recurrent wheezing during follow-up. SP-D and MBL were measured using enzyme-linked immunosorbent assay in serum collected on admission and compared with controls. Their levels were evaluated in relation to the symptom severity during admission and recurrence of wheezing after discharge. RESULTS: Serum SP-D increased significantly in the patients (P<0.01), but MBL showed no difference compared to the controls. SP-D levels were significantly higher in severe group compared with nonsevere group (P<0.05). SP-D levels in the patients with recurrent wheezing after discharge were significantly higher than in those without (P<0.05). MBL showed no difference in relation to the symptom severity or recurrence of wheezing. CONCLUSION: Our study showed that serum SP-D was associated with the severity of RSV bronchiolitis and suggests that it might be a biomarker of lung injury and recurrence of wheezing illnesses in the young children admitted with their first RSV bronchiolitis.

The effect of conglutinin on production of reactive oxygen species in bovine granulocytes

Conglutinin is a high molecular-weight lectin originally detected in bovine serum. It belongs to the family of collectins that bind sugar residues in a Ca(2+)-dependent manner and are effector molecules in innate immunity. Conglutinin appears to play an important role in immune defense mechanisms, showing antiviral and antibacterial activities when tested in vivo and in vitro. The present study evaluated the effect of conglutinin on the respiratory bursts in bovine peripheral phagocytes. Using nitroblue tetrazolium and hydrogen peroxide assays, we showed that sugar ligand-bound conglutinin stimulated the production of superoxide and H2O2 in granulocytes whereas the non-sugar-bound form of conglutinin inhibited these processes. These results indicate that both forms of conglutinin are able to interact with surface leukocyte receptors but have opposite effects on phagocytic activity. Our findings suggest that conglutinin bound to sugar residues on microbial surfaces can induce oxygen burst in phagocytes, and thereby mediates the elimination of pathogens and prevents the spread of infection.

Cloning and functional analysis of the collectin gene from the grass carp Ctenopharyngodon idella / 生物工程学报

The grass carp (Ctenopharyngodon idella) collectin gene was cloned from mixed liver and kidney cDNA library. The full length sequence of grass carp collectin was 1128 bp, contained a 5' untranslated region of 229 bp and a 3' untranslated region of 104 bp. The open reading frame of grass carp collectin was 795 bp which could code a 264 amino acids polypeptide, including a terminal codon. Phylogenetic analyses showed that grass carp collectin shared the highest homology with that of zebrafish (Danio rerio). To understand the function of grass carp collectin, we expressed and purified the recombinant protein (P(CRD)) that comprised carbohydrate recognition domain (CRD). Agglutination of Aeromonas hydrophila and Staphylococcus aureus etc. and sugars inhibition experiments showed that: galactose, glucose, mannose and maltose could inhibit the agglutination of Aeromonas hydrophila. Maltose could lower the agglutination of Staphylococcus aureus, whereas peptidoglycan and glucose inhibited it well. In addition, the activity of grass carp collectin could not dependent on Ca(2+).

Proteomic Analysis of Differentially Expressed Proteins in Bovine Endometrium with Endometritis

Endometritis is one of the primary reasons for reproductive failure. In order to investigate endometritis-associated marker proteins, proteomic analysis was performed on bovine endometrium with endometritis. In bovine endometritis, desmin, alpha-actin-2, heat-shock protein (HSP) 27, peroxiredoxin-6, luteinizing hormone receptor isoform 1, collectin-43 precursor, deoxyribonuclease-I (DNase-I), and MHC class I heavy chain (MHC-Ih) were up-regulated. In contrast, transferrin, interleukin-2 precursor, hemoglobin beta subunit, and potassium channel tetramerisation domain-containing 11 (KCTD11) were down-regulated in comparison to normal endometrium. The proteomic results were validated by semiquantitative-PCR and immunoblot analysis. The mRNA levels of desmin, transferrin, alpha-actin-2, HSP27, KCTD11, and MHC-Ih were up-regulated by over 1.5-fold, and showed a pattern similar to their proteomic profiles. Desmin and alpha-actin-2 protein showed positive correlations between proteomic analysis and immunoblot analysis. These results suggest that desmin and alpha-actin-2 may play important roles in endometritis-related function, and could be useful markers for the diagnosis of bovine endometritis.

Lectina ligante de manose (MBL): características biológicas e associação com doenças / Mannan-binding lectin (MBL): biological characteristics and diseases association

Objetivo: Fazer levantamento de dados recentes relacionados a aspectos estruturais e biológicos da lectina ligante de manose (MBL), assim como da sua participação na fisiopatogenia de diversas doenças. Fonte de dados: Informações contidas em livros, assim como em periódicos acessados principalmente através do Portal da Capes e Pubmed. Síntese dos dados: A MBL é uma proteína com importante participação no sistema imunológico inato e representa a proteína central da ativação da via das lectinas do complemento. A concentração plasmática da MBL é determinada genetica¬mente e varia significativamente entre os indivíduos. A MBL reconhece unidades de açúcares como N-acetil-glucosamina, manose, N-acetil-manosamina, fucose e glucose na superfície de microorganismos, possibilitando a interação com vírus, bactérias, leveduras, fungos e protozoários, levando à sua opsoni¬zação e fagocitose. Dados recentes mostram que a MBL participa na modulação da inflamação e apoptose ao ligar-se a recep¬tores na superfície de fagócitos. A MBL apresenta papel complexo nas doenças. Sua deficiência tem sido associada a maior susceptibilidade a doenças infecciosas, especialmente por patógenos extracelulares. Por outro lado, altas concentrações de MBL sérica têm sido associadas a infecções por microorganismos intracelulares como Leishmania spp. e M. leprae. Há evidências que a MBL também tem participação em condições co¬mo abortos espontâneos, doenças autoimunes e inflamatórias. A MBL é considerada uma proteína de fase aguda, embora apresente aumentos sé ricos modestos quando comparada à proteína C reativa (PCR). Conclusões: Estudos evidenciam ao longo dos anos a notável influência da MBL na resposta inata do hospedeiro e sua participação nos diferentes processos inflamatórios e infecciosos, respaldados na perspectiva que representa a terapia de reposição dessa proteína.

Up-regulation of Surfactant Protein-A in Chronic Sialadenitis / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Surfactant protein-A (SP-A) is a member of the collectin family, and plays an important role in the first-line airway defense. The purpose of study was to examine the expression of SP-A mRNA and protein in human salivary glands, and to investigate its up-regulation during inflammatory conditions of salivary glands. MATERIALS AND METHOD: Reverse transcription-polymerase chain reaction was performed on salivary gland tissues from ten patients with chronic sialadenitis and ten samples of normal salivary gland tissue. The expression levels of SP-A to GAPDH (glyceraldehyde-3-phosphate dehydrogenase) transcripts were semi-quantified by densitometry. We also characterized the cellular localizations of SP-A protein immunohistochemically. RESULTS: SP-A mRNA and protein were detected in normal and chronic sialadenitis glands. The expression levels of SP-A mRNA in salivary glands with chronic sialadenitis was significantly increased as compared with normal salivary glands. Immunohistochemical staining revealed SP-A immunoreactivity in the ductal epithelia of normal salivary glands and chronic sialadenitis, and stronger immunoreactivity was observed in chronic sialadenitis tissues. CONCLUSION: SP-A is present in the human salivary gland epithelium and is up-regulated during chronic sialadenitis. These results suggest that salivary gland SP-A may play an important role in the innate host defense of human salivary glands.

Genetic variation of mannose-binding protein associated with glomerular immune deposition in IgA nephropathy / 中华医学杂志(英文版)

<p><b>OBJECTIVE</b>To investigate the relationship between codon 54 gene polymorphism of the host defense molecule, mannose-binding protein (MBP), and the patterns of glomerular immune deposition in IgA nephropathy (IgAN).</p><p><b>METHODS</b>IgAN patients with different patterns of glomerular immune deposition were selected and divided into two groups. Group A consisted of 77 patients with glomerular IgA and C3 deposits, and Group AGM consisted of 70 patients with glomerular IgA, IgG, IgM, C3 and Clq deposits. Clinical features and laboratory relevant data of all patients were collected. One-hundred and forty healthy adults were recruited as normal controls. The MBP gene codon 54 GGC/GAC polymorphism was investigated by using polymerase chain reaction and restriction fragment length polymorphism.</p><p><b>RESULTS</b>The genotype frequency of GGC/GAC heterozygotes was significantly higher in Group AGM as compared with that of Group A (41.4% vs 19.5%, P < 0.01) or normal subjects (41.4% vs. 26.4%, P < 0.05), while no difference was found in the distribution of MBP genotypes between Group A and normal subjects. GAC allele frequency was also higher in Group AGM than that in Group A (0.24 vs. 0.14, P < 0.05) or normal subjects (0.24 vs. 0.15, P < 0.05). The variant allele (GAC) was markedly associated with Group AGM (OR = 1.95, 95% CI: 1.06 - 3.58). In both Group A and Group AGM, more patients carrying the variant allele had episodes of upper respiratory or gastrointestinal infections prior to the onset of IgAN than those with wild homozygotes (GGC/GGC).</p><p><b>CONCLUSIONS</b>Genetic variation of the host defense molecule, MBP, may be involved in the formation of the diverse patterns of glomerular immune deposition in IgAN. The variant allele of the MBP gene may partially account for abundant immune deposits in some IgAN patients.</p>

Expression of Collectin in the Human Nasal Mucosa / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Collectins (surfactant protein A and D) are proteins with collagen tails and globular lectin domains that appear to play an important role in the first line of host defense in mammalians. However, it is not known if collectins are also present in human nasal mucosa. The purpose of this study was to investigate the expression of collectin proteins in human nasal mucosa and to compare the expressions of SP-A and D mRNA in the normal nasal mucosa and in chronic inflammatory nasal diseases. MATERIALS AND METHOD: Ten chronic rhinosinusitis patients were recruited and ten normal nasal mucosae were used as normal controls. Reverse transcriptase-polymerase chain reaction was performed to detect SP-A and SP-D mRNA. The level of collectin and GAPDH (glyceraldehyde-3-phosphate dehydrogenase) transcripts were semi-quantified with the desitometry. We have characterized the cellular localization of SP-A and SP-D protein using immunohistochemistry. RESULTS: SP-A2/GAPDH mRNA ratio in chronic rhinitis nasal mucosa is greater compared with that in normal nasal mucosa (p<0.05). SP-A protein was expressed in the nasal epithelium and in the epithelial cells of the submucosal glands. SP-D mRNA and protein were not expressed in the nasal mucosa. CONCLUSION: These data provide the first evidence of the presence of collectins in the human nasal mucosa. These results suggested that up-regulation of collectin in chronic rhinosinusitis may be a protective response for the nasal mucosa.

Influence of non-MHC genes on lymphocyte response to Mycobacterium tuberculosis antigens & tuberculin reactive status in pulmonary tuberculosis.

BACKGROUND & OBJECTIVES: Major histocompatibility complex (MHC) genes are known to influence the immune functions. In the present study, the influence of non-MHC genes such as mannose binding protein (MBP), vitamin D receptor (VDR) and interleukin-1 receptor antagonist (IL-1RA) gene polymorphisms on lymphocyte response to Mycobacterium tuberculosis culture filtrate antigen (10 micrograms/ml) was studied in 44 patients with active pulmonary TB and the family contacts (35) and in 32 normal healthy subjects. The influence of these gene polymorphisms on tuberculin (1TU of PPD of M. tuberculosis) reactivity status in 146 pulmonary TB patients was also studied. METHODS: The MBP and VDR genes were amplified using polymerase chain reaction (PCR) and genotyping was carried out using sequence specific oligonucleotide probes by dot blot and IL-1RA by agarose gel electrophoresis. RESULTS: A significantly decreased lymphocyte response to M. tuberculosis antigen was seen in pulmonary TB patients positive for functional mutant homozygotes of MBP (OO) compared to heterozygote carriers (AO; P < 0.02) and wild homozygotes (AA; P < 0.01). The variant mutant genotype (tt) of VDR gene was associated with an increased lymphocyte response in control subjects compared to active TB patients with tt genotype (P < 0.05). Heterozygote carriers of MBP (AO) were associated with a significantly (P < 0.001) decreased tuberculin reactivity compared to wild homozygotes (AA). The VDR genotype Tt (heterozygote carrier) was associated with an increased tuberculin reactivity in female TB patients as compared to male patients (P < 0.001). INTERPRETATION & CONCLUSIONS: The present study suggested that MBP and VDR genes influence the cell mediated immune response in pulmonary TB patients. Non-MHC genes along with HLA-Class II genes/gene products may be playing an immunoregulatory role in the mechanism of susceptibility/resistance to tuberculosis.