Zinc alpha 2 glycoprotein as an early biomarker of diabetic nephropathy in patients with type 2 diabetes mellitus / Zinco-alfa2-glicoproteina (ZAG) como biomarcador precoce de nefropatia diabética em pacientes com diabetes mellitus tipo 2

Abstract Introduction: Although microalbuminuria remains the gold standard for early detection of diabetic nephropathy (DN), it is not a sufficiently accurate predictor of DN risk. Thus, new biomarkers that would help to predict DN risk earlier and possibly prevent the occurrence of end-stage kidney disease are being investigated. Objective: To investigate the role of zinc-alpha-2-glycoprotein (ZAG) as an early marker of DN in type 2 diabetic (T2DM) patients. Methods: 88 persons were included and classified into 4 groups: Control group (group I), composed of normal healthy volunteers, and three patient groups with type 2 diabetes mellitus divided into: normo-albuminuria group (group II), subdivided into normal eGFR subgroup and increased eGFR subgroup > 120 mL/min/1.73m2), microalbuminuria group (group III), and macroalbuminuria group (group IV). All subjects were submitted to urine analysis, blood glucose levels, HbA1c, liver function tests, serum creatinine, uric acid, lipid profile and calculation of eGFR, urinary albumin creatinine ratio (UACR), and measurement of urinary and serum ZAG. Results: The levels of serum and urine ZAG were higher in patients with T2DM compared to control subjects and a statistically significant difference among studied groups regarding serum and urinary ZAG was found. Urine ZAG levels were positively correlated with UACR. Both ZAG levels were negatively correlated with eGFR. Urine ZAG levels in the eGFR ˃ 120 mL/min/1.73m2 subgroup were higher than that in the normal eGFR subgroup. Conclusion: These findings suggest that urine and serum ZAG might be useful as early biomarkers for detection of DN in T2DM patients, detectable earlier than microalbuminuria.

Resumo Introdução: Embora a microalbuminúria continue sendo o padrão ouro para a detecção precoce da nefropatia diabética (ND), ela não é um preditor suficientemente preciso do risco de ND. Assim, novos biomarcadores para prever mais precocemente o risco de ND e possivelmente evitar a ocorrência de doença renal terminal estão sendo investigados. Objetivo: Investigar a zinco-alfa2-glicoproteína (ZAG) como marcador precoce de ND em pacientes com debates mellitus tipo 2 (DM2). Métodos: Os 88 indivíduos incluídos foram divididos em quatro grupos: grupo controle (Grupo I), composto por voluntários saudáveis normais; e três grupos de pacientes com DM2 assim divididos: grupo normoalbuminúria (Grupo II), subdivididos em TFG normal e TFG > 120 mL/min/1,73 m2), grupo microalbuminúria (Grupo III) e grupo macroalbuminúria (Grupo IV). Todos foram submetidos a urinálise e exames para determinar glicemia, HbA1c, função hepática, creatinina sérica, ácido úrico, perfil lipídico, cálculo da TFG, relação albumina/creatinina (RAC) e dosagem urinária e sérica de ZAG. Resultados: Os níveis séricos e urinários de ZAG foram mais elevados nos pacientes com DM2 em comparação aos controles. Foi identificada diferença estatisticamente significativa entre os grupos estudados em relação aos níveis séricos e urinários de ZAG. Os níveis urinários de ZAG foram positivamente correlacionados com a RAC. Ambos os níveis de ZAG foram negativamente correlacionados com TFG. Os níveis urinários de ZAG no subgrupo com TFG ˃ 120 mL/min/1,73m2 foram maiores do que no subgrupo com TFG normal. Conclusão: Constatamos que a ZAG sérica e urinária pode ser um útil biomarcador precoce para detecção de ND em pacientes com DM2, sendo detectável mais precocemente que microalbuminúria.

Effect of curcumin on visfatin and zinc-α2-glycoprotein in a rat model of non-alcoholic fatty liver disease

ABSTRACT PURPOSE: To investigate the effect of curcumin on visfatin and zinc-α2-glycoprotein (ZAG) expression levels in rats with non-alcoholic fatty liver disease (NAFLD). METHODS: Fifty-six male rats were randomly divided into a control group (n=16) and model group (n=40) and were fed on a normal diet or a high-fat diet, respectively. Equal volumes of sodium carboxymethyl cellulose (CMC) were intragastrically administered to the control group for 4 weeks. At the end of the 12th week, visfatin and ZAG protein expression levels were examined by immunohistochemistry. Visfatin mRNA levels were measured by semi-quantitative reverse transcription polymerase chain reaction. RESULTS: Compared with the control group, the model group showed significantly increased expression of visfatin in liver tissue (P < 0.01) and significantly decreased expression of ZAG (P < 0.01). These effects were ameliorated by curcumin treatment. CONCLUSIONS: Visfatin and zinc-α2-glycoprotein may be involved in the pathogenesis of NAFLD. Treatment of NAFLD in rats by curcumin may be mediated by the decrease of visfatin and the increase of non-alcoholic fatty liver disease.

Recombinant expression and purification of the bovine acidic Seminal Fluid Protein

The acidic Seminal Fluid Protein (aSFP), a 12.9 kDa protein is a maker for bovine semen freezability possibly due to its antioxidant activity and effect on sperm mitochondrial function. However, its precise function on sperm preservation during freezing thaw is poorly understood. The use of recombinant DNA technology allows new approaches on the study of function and structure of proteins, and its production in procaryote systems offers several advantages. The present work describes the recombinant expression of the bovine aSFP and its binding properties. A cDNA library from the bovine seminal vesicle was used as template for amplification of the aSFP coding region. The amplicon was cloned into a pET23a (+) vector and transformed into E.coli BL21 pLysS strain. The recombinant expression was obtained in E coli. One step ion immobilized affinity chromatography was performed, resulting in high yield of purified protein. To determine the bioactivity of the r aSFP, the protein was incubated in different concentrations with 10 7 spermtozoa at 37°C for 5 h. Western blotting and fluorescence microscopy analyses showed the ability of the recombinant aSFP to attach to the spermatozoa. Based on our results, the described method can be used to obtain mg levels of recombinant aSFP.

Presencia de epimastigotes de Trypanosoma cruzi en el plasma seminal de ratones con infección aguda / Trypanosoma cruzi epimastigotes in seminal plasma in acute infected mice

Se reporta la presencia de formas evolutivas de Trypanosoma cruzi en el plasma seminal (PS) de ratones NMRI, inoculados por vía subcutánea con 2x104 tripomastigotes metacíclicos cepa P6 obtenidos de Rhodnius prolixus. Al separar las muestras de sangre a los 15 días pos-infección, un ratón eyaculó espontáneamente y el examen directo del PS reveló la presencia de formas epimastigotes de T. cruzi en activo movimiento mezclados con los espermatozoides. Las preparaciones del PS coloreadas con Giemsa, mostraron formas epimastigotes libres y en división, tripomastigotes y amastigotes extracelulares y dentro de células fagocíticas. Los resultados de este estudio revelaron los diferentes estadios de T. cruzi en el PS de ratón, con morfogénesis similar a como ocurre en el insecto vector. El parasitismo encontrado en el PS del ratón con infección aguda, aporta importante información epidemiológica sobre la vía de transmisión sexual de T. cruzi, principalmente entre la población de reservorios silvestres que se encuentran en áreas endémicas y no endémicas para la enfermedad de Chagas.

We report the presence of evolving forms of Trypanosoma cruzi in the seminal plasma (SP) of NMRI mice subcutaneously inoculated with 2x104 metacyclic trypomastigotes obtained from P6 strain Rhodnius prolixus. When taking blood samples at 15 days post-infection, the mouse spontaneously ejaculated and the direct SP exam revealed the presence of active epimastigotes of T. cruzi mixed with spermatozoids. SP preparations stained with Giemsa showed free and dividing epimastigotes, extracellular trypomastigotes and amastigotes, as well as, within phagocytic cells. The results showed the presence of T. cruzi at the different stages of its life cycle in the mouse PS, observing similar morphogenesis in the PS to the one known in the insect vector. The parasitism found in the SP of this mouse with acute infection, provides important epidemiological information about the T. cruzi pathway of sexual transmission, mainly among the population of wild reservoirs found in endemic and non-endemic areas for Chagas`disease.

Topografia de ligação de proteínas do plasma seminal à membrana de espermatozoides bovinos epididimários e ejaculados / Binding patterns of seminal plasma plasma proteins on bovine epididymal and ejaculated sperm membrane

The present study was designed to investigate the topographical distribution of seminal plasma (SP) proteins on epididymal and ejaculated bovine sperm. Using immunocytochemistry and confocal microscopy the binding patterns of bovine SP proteins BSP-A3, albumin, transferrin, prostaglandin D-synthase (PGDS) and nucleobindin in ejaculated and cauda epididymal sperm from adult bulls were evaluated. Experiments were performed using sperm from 5 males. Data showed a positive signal, only detected for anti-PGDS, in the acrosomal cap of epididymal and ejaculated sperm. In ejaculated sperm, a very weak signal for nucleobindin 2 in the midpiece and equatorial regions was detected, using the anti-rat nucleobindin. BSP-A3 was detected on all sperm regions studied, with a more evidenced signal in acrosome and midpiece. However, no binding was detected for albumin or transferrin in neither epididymal nor ejaculated sperm. In conclusion, PGDS, BSP-A3 and nucleobindin interact directly with bovine sperm, with specific topographic distribution. These findings may add to the knowledge of how these proteins modulate sperm functions, thus providing fundamental support for studies designed to evaluate how they influence sperm functions.

Investigou-se a distribuição topográfica da ligação de proteínas seminais à membrana de espermatozoides bovinos epididimários e ejaculados. Utilizando imunocitoquímica e microscopia confocal, avaliaram-se a topografia de ligação das proteínas BSP-A3, albumina, transferrina, prostaglandina D sintetase (PGDS) e nucleobindina 2 (NUC2) à membrana espermática. Os experimentos foram realizados utilizando espermatozoides de cinco touros. Os resultados mostraram que, para espermatozoides epididimários, somente detectou-se a PGDS na crista do acrossomo. Nos espermatozoides ejaculados, a PGDS ligou-se de forma mais intensa à crista acrossômica, enquanto a NUC2 apresentou sinal bastante fraco na peça intermediária e região equatorial. A BSP-A3 ligou-se a todas as regiões estudadas, de forma mais intensa na peça intermediária e acrossomo. Nenhum sinal foi detectado para albumina ou transferrina, seja em espermatozoides epididimários ou ejaculados. Concluiu-se que PGDS, BSP-A3 e NUC2 interagem diretamente com espermatozoides bovinos, e mostrou distribuição topográfica específica. Estes achados permitem melhor compreensão sobre o papel desempenhado por essas proteínas na regulação da função espermática e da fertilidade.

Porcine oviduct sperm binding glycoprotein and its deleterious effect on sperm: a mechanism for negative selection of sperm?

In their journey through the oviduct some subpopulations of sperm are preserved in a reservoir, while others are negatively selected. Sperm binding glycoprotein (SBG) is a pig oviductal epithelial cell glycoprotein that produces, under capacitating conditions, acrosome alteration, p97 tyrosine-phosphorylation and reduction of the motility of sperm. In this paper, we show that SBG is accessible at the extracellular surface of the oviductal epithelial cells, supporting a sperm interaction biological role in situ. We analyze the possible dependence of the tyrosine-phosphorylation of p97 on the PKA mechanism, finding that apparently it is not PKA dependent. Also, after SBG treatment the phosphorylated proteins locate mainly at the detached periacrosomal region and at the tail of sperm; the latter may be related to SBG's motility reduction effect. The study of the time course effect of SBG on sperm as detected by chlortetracycline (CTC) staining and of its binding to sperm by immunodetection in conjunction with CTC, shows results in agreement with the hypothesis that this glycoprotein is involved in the alteration of acrosomes in a specific sperm subpopulation. The results suggest that SBG may be part of a mechanism for negative selection of sperm.

Ion-exchange chromatography used to isolate a spermadhesin-related protein from domestic goat (Capra hircus) seminal plasma

Mammalian seminal plasma contains among others, proteins called spermadhesins, which are the major proteins of boar and stallion seminal plasma. These proteins appear to be involved in capacitation and sperm-egg interaction. Previously, we reported the presence of a protein related to spermadhesins in goat seminal plasma. In the present study, we have further characterized this protein, and we propose ion-exchange chromatography to isolate this seminal protein. Semen was obtained from four adult Saanen bucks. Seminal plasma was pooled, dialyzed against distilled water and freeze-dried. Lyophilized proteins were loaded onto an ion-exchange chromatography column. Dialyzed-lyophilized proteins from the main peak of DEAE-Sephacel were applied to a C2/C18 column coupled to an RP-HPLC system, and the eluted proteins were lyophilized for electrophoresis. The N-terminal was sequenced and amino acid sequence similarity was determined using CLUSTAL W. Additionally, proteins from DEAE-Sephacel chromatography step were dialyzed and submitted to a heparin-Sepharose high-performance liquid chromatography. Goat seminal plasma after ion-exchange chromatography yielded 6.47 +/- 0.63 mg (mean +/- SEM) of the major retained fraction. The protein was designated BSFP (buck seminal fluid protein). BSFP exhibited N-terminal sequence homology to boar, stallion and bull spermadhesins. BSFP showed no heparin-binding capabilities. These results together with our previous data indicate that goat seminal plasma contains a protein that is structurally related to proteins of the spermadhesin family. Finally, this protein can be efficiently isolated by ion-exchange and reverse-phase chromatography.