[SP1 identified as a transcription factor of miR-122-5p].

OBJECTIVE: To study the transcription factors of the spermatogenesis-related promoter mir-122-5p. METHODS: SP1 and GATA4 were predicted as the possible transcription factors of the mir-122-5p promoter by bioinformatics analysis, followed by construction of the double luciferase pGL3-mir-122-5p promoter vector, pcDNA3.1 (+) -SP1 expression vector and pcDNA3.1 (+) -GATA4 expression vector, respectively. The pcDNA-SP1+pGL3-basic mixture plasmid and pcDNA-SP1+ pGL3-miR-122-5p promoter mixture plasmid, pcDNA-GATA4+pGL3-basic mixture plasmid and pcDNA-GATA4+pGL3-miR-122-5p promoter mixture plasmid were transferred into 293T cells. The enzyme activity was detected the Dual-Luciferase Reporter Assay System. RESULTS: The fluorescence value of the pcDNA3.1+pGL3-miR-122 promoter was 0.0362 ± 0.0004, significantly higher than that of the pcDNA3.1+pGL3-basic group (P < 0.05), indicating the successful construction of the mouse miR-122-5p promoter luciferase reporter plasmid. The fluorescence value was markedly higher in the pcDNA -SP1 + pGL3-miR-122-5p promoter than in the pcDNA -SP1+pGL3-basic group, suggesting that the transcription factor SP1 could promote the transcription of miR-122. There was no statistically significant difference in the fluorescence value between the pcDNA -gata4+pGL3-basic transfection and pcDNA -GATA4+pGL3-miR-122-5p promoter transfection groups, indicative of the inability of GATA4 to promote the transcription of miR-122-5p. CONCLUSIONS: The transcription factor SP1, rather than GATA4, can promote the transcription of miR-122-5p.

[Construction of RNA interfering lentiviral vector of occludin and its role in tight junctions].

OBJECTIVE: To investigate the role of occludin in tight junction (TJ) in vitro. METHODS: We constructed RNA interfering lentiviral vectors and transfected them into TM4 cells. Then we detected their inhibitory effect on occuldin by RT-PCR and Western blot and analyzed the role of occuldin in TJ using an in vitro TJ cell model. RESULTS: The pLenti 6.3-EGFP-occludin-miR expression vector was successfully constructed. The results of RT-PCR and Western blot showed that pLenti 6.3-EGFP-occludin-miR-3 significantly inhibited the expression of occludin (P < 0.05), which was remarkably lower than in the blank control and the pLenti 6.3- EGFP transfection group (0.7534 ± 0.089 vs 1.000 and 1.056 ± 0.025, P < 0.05). The expression of occludin was markedly suppressed and the tightness of tight junctions decreased in the TM4 cells transfected with pLenti 6.3-EGFP-occludin-miR-3. CONCLUSIONS: The pLenti 6.3-EGFP-occludin-miR expression vector was successfully constructed, and occludin is one of the functional proteins that maintain tight junctions.

miR-122-5p regulates the tight junction of the blood-testis barrier of mice via occludin : miR-122-5p can regulate the tight junction.

BACKGROUND: Occludin protein is the primary assembling protein of TJs and the structural basis for tight junction formation between Sertoli cells in the spermatogenic epithelium. The expression of miR-122-5p and occludin are negatively correlated. In order to investigate the regulation mechanism of miR-122-5p on occludin and TJ, the present study isolated primary Sertoli cells from C57BL/6 mice, identified a transcription factor of miR-122-5p in testicle, studied the modulating loci of miR-122-5p on occludin using a dual-luciferase reporter assay, analyzed the regulate of miR-122-5p on the expression of occludin with real-time RT-PCR and Western blot, and studied the effect of miR-122-5p on the tight junction using a Millicell Electrical Resistance System. RESULTS: The relative luciferase activity in the pcDNA-Sp1 + pGL3-miR-122-5p promoter group was significantly higher than that in the pcDNA-Sp1 + pGL3-basic group, which suggests that transcript factor Sp1 promotes the transcription of miR-122-5p. The relative luciferase activity in the occludin 3'-UTR (wt) + miR-122-5p mimic group was significantly lower than that in the other groups (p < 0.01), which indicates that miR-122-5p modulates the expression of occludin via the ACACTCCA sequence of the occludin-3'UTR. The levels of occludin mRNA and protein in the miR-122-5p mimic group were significantly lower than that in the other groups (p < 0.05), which indicates that miR-122-5p reduces the expression of occludin. The trans-epithelial resistance of the miR-122-5p mimic group was significantly lower than that of the blank control group after day 4 (p < 0.05), which indicates that miR-122-5p inhibited the assembly of the inter-Sertoli TJ permeability barrier in vitro. CONCLUSION: These results displayed that miR-122-5p could regulate tight junctions via the Sp1-miR-122-5p-occludin-TJ axis.

ABSTRAIT: CONTEXTE: La protéine occludine est. la principale protéine d'assemblage des jonctions serrées (JS), et la base structurelle pour la formation de ces jonctions entre les cellules de Sertoli dans l'épithélium séminifère. L'expression de miR-122-5p et de l'occludine sont négativement corrélées. Afin d'étudier le mécanisme de régulation de l'occludine et des TJ par miR-122-5p, nous avons, dans la présente étude, isolé des cellules primaires de Sertoli de souris C57BL/6, identifié un facteur de transcription de miR-122-5p dans le testicule, étudié les loci de miR-122-5p modulants l'occludine par le biais d'un système rapporteur à 2 luciférases, analysé la régulation de miR-122-5p sur l'expression de l'occludine par qRT-PCR et Western blot, et étudié l'effet de miR-122-5p sur les jonctions serrées à l'aide d'un Système de Résistance Electrique Millicell. RéSULTATS: L'activité relative de la luciférase dans le groupe du promoteur de pcDNA46 Sp1 + pGL3-miR-122-5p était significativement plus élevée que celle observée dans le groupe pcDNA-Sp1 + pGL3-basique, ce qui suggère que le facteur de transcription Sp1 favorise la transcription de miR-122-5p. L'activité relative de la luciférase dans le groupe 3'-UTR (wt) + miR-122-5p mimant l'occludine était significativement inférieure à celle des autres groupes (p < 0,01), ce qui indique que miR-122-5p module l'expression de l'occludine via la séquence ACACTCCA en 3' UTR de l'occludine. Les niveaux d'ARNm et de protéine occludine dans le groupe mimant miR-122-5p étaient significativement inférieurs à ceux des autres groupes (p < 0,05), ce qui indique que miR-122-5p inhibe l'expression de l'occludine. La résistance transépithéliale du groupe mimant miR-122-5p était significativement inférieure à celle du groupe témoin vierge après le jour 4 (p < 0.05), ce qui indique que miR-122-5p inhibe in vitro l'assemblage des jonctions serrées de la barrière de perméabilité inter-Sertolienne. CONCLUSIONS: Ces résultats montrent que miR-122-5p pourrait réguler les jonctions serrées via l'axe Sp1-miR-122-5p-occludine.

A 22-amino-acid peptide regulates tight junctions through occludin and cell apoptosis.

Occludin is a structural protein of tight junctions (TJ) in the blood-testis barrier (BTB). A 22-amino-acid peptide (22AA) in the second extracellular loop can reversibly regulate TJ, but its regulatory mechanism is unknown. In this study, a 22AA-induced TJ destruction animal model was constructed to investigate the effect of 22AA on Sertoli cells (SCs) and spermatid counts and cell apoptosis at different time points using a multiplex immunofluorescence technique. The effect of 22AA on the location and distribution of occludin was analyzed via dual confocal fluorescence microscope. Western blotting was used to analyze dynamic changes in occludin expression. Real-time RT-PCR was used to analyze miR-122-5p expression changes. Sperm density counts and mating methods were used to analyze the effect of 22AA on fertility in mice. The results showed that 22AA promoted SC and spermatid apoptosis, downregulated occludin, upregulated miR-122-5p, and decreased sperm density and litter size before 27 days (27D). After 27D, the expression of occludin increased again, miR-122-5p expression decreased again, both sperm density and litter size returned to normal, apoptosis stopped, and spermatogenesis began to recover. Therefore, it can be concluded that 22AA can destroy TJ by downregulating occludin and inducing cell apoptosis. After 27D, TJ and spermatogenesis functions return to normal.

Correlation Analysis of miR-122-5p and Occludin with Sperm Density in Oligospermia Patients' Sperm.

BACKGROUND: To analyze the correlation of miR-122-5p and occludin with sperm density in oligospermia patients' sperm. METHODS: The expression of miR-122-5p and its target protein occludin in the sperm and exfoliated cells of semen were studied using real-time reverse transcription-polymerase chain reaction and Western blot analysis. RESULTS: The expression level of miR-122-5p in the sperm and exfoliated cells of patients with oligospermia semen was 0.0880 ± 0.02581 and 0.5110 ± 0.1087, respectively, which were lower than those in the normal sperm (0.7840 ± 0.2318 and 7.000 ± 2.136), and the differences were significant. The expression of occludin in the sperm of patients with oligospermia was 3.725 ± 0.5870, which was significantly higher than that in the normal group (1.055 ± 0.03344). No difference was found in the expression of occludin between sperm and exfoliated cells of patients with oligospermia. The sperm density positively correlated with the expression of miR-122-5p in the sperm and exfoliated cells and negatively correlated with the expression of occludin in the sperm. CONCLUSIONS: The results of the study suggested that the low expression of miR-122-5p might affect the proliferation and differentiation of spermatogenic cells, leading to a decrease in the sperm count. The high expression of occludin also affected the tight junction of spermatogenic cells through testis and led to a decrease in the sperm count.

[Cross immunogenicity between Ia-associated invariant chains of chicken (Gallus domestiaus) and Muscovy duck (Cairina moschata)].

OBJECTIVE: To explore the cross immunogenicity between Ia-associated invariant chain (Ii) of chicken (CIi) and Ii of Muscovy duck (MDIi). METHODS: The immunoreactivity between mouse anti-CIi serum and the MDIi expressed by prokaryotic cell, and the immunoreactivity between the mouse anti-MDIi serum and the CIi expressed by prokaryotic cell were detected through indirect ELISA. To detect the immunoreactivity between the mouse anti-CIi serum and the MDIi of the spleen tissues of Muscovy duck, and the immunoreactivity between the mouse anti-MDIi serum and the CIi of the liver tissues of chicken (tissular CIi), the fluorescence immunohistochemistry assay was performed using DyLight 488 affiniPure goat anti-mouse IgG as the second antibody. The fluorescence intensity was detected in each tissue by Leica fluorescence microscopic imaging system. RESULTS: The titer of ELISA reactivity between mouse anti-MDIi serum and the expressed CIi was 1:8000. The titer of ELISA reactivity between mouse anti-CIi serum and the expressed MDIi was 1:16 000. The mouse anti-CIi serum and anti-MDIi serum could respectively react with tissular MDIi and tissular CIi, showing visible green fluorescence in corresponding cells of each tissue. But the fluorescence intensities in the above tissues were weaker than those in positive control tissues in which the mouse anti-MDIi serum or anti-CIi serum reacted with tissular MDIi or tissular CIi respectively. CONCLUSION: The cross immunogenicity between CIi and MDIi has been verified through the immunological experiments. The molecular basis of common antigen epitope formation between CIi and MDIi involves the conservation of the two Ii sequences, which reveals the high conservative property of Ii among variant birds from the perspective of immunology.

[Preparation and characterization of polyclonal antibody against Ia-associated invariant chain of Muscovy Duck (Cairina moschata)].

OBJECTIVE: To prepare polyclonal antibody against invariant chain of Muscovy duck (Cairina moschata) (MDIi) and identify its reaction with MDIi extracted from tissues of Muscovy duck. METHODS: MDIi was amplified by PCR and used to construct the prokaryotic expression vector of pET-32a/MDIi by linking with the plasmid of pET-32a. Then pET-32a/MDIi was transformed into E.coli Rosetta to induce the prokaryotic expression. After identified by SDS-PAGE, prokaryotic expression products were further purified from running gel of SDS-PAGE and injected into mice to prepare polyclonal antibody against MDIi. The titer and specificity of the polyclonal antibody against MDIi were analyzed by indirect ELISA and Western blotting, respectively. The intensity of reaction between the polyclonal antibody and MDIi extracted from tissues of Muscovy duck was also identified by indirect ELISA. RESULTS: The prokaryotic expression vector pET-32a/MDIi was successfully constructed. About 40 kD recombinant proteins of MDIi were confirmed to be expressed in the form of inclusion body in Rosetta. Polyclonal antibody against MDIi with a titer of 1:128 000 was obtained from the immunized mice and its high specificity was demonstrated by Western blotting. The titer of reaction between the polyclonal antibody and MDIi was 1:32 000. CONCLUSION: The polyclonal antibody against MDIi was successfully prepared with a high titer and specificity. It has a strong immune reaction with MDIi extracted from tissues of Muscovy duck.

Single-chain antibody against human lipocalin-type prostaglandin D synthase: construction, expression, purification, and activity assay.

An active form of single-chain antibody (ScFv) from murine monoclonal antibody 4A7, which is specific for lipocalin-type prostaglandin D synthase (L-PGDS), was produced in Escherichia coli. The complementary DNA fragments encoding the variable regions of heavy chain (VH) and light chain (VL), which amplified from hybridoma 4A7 producing a monoclonal antibody (IgG1) against L-PGDS, were connected by a (Gly4Ser)3 linker using an assembly polymerase chain reaction. The resultant ScFv were cloned into the vector pGEM and expressed in E. coli as inclusion bodies. The expressed ScFv fusion proteins were purified by Ni2+-nitrilotriacetic acid chromatography. The purity and activity of purified ScFv were confirmed by SDS-PAGE and ELISA. The result revealed that 4A7 ScFv conserved the same characteristics of specific recognition and binding to sperm as the parental 4A7 monoclonal antibody.

Relationship between contents of lipocalin-type prostaglandin D synthase on the surface of infertility sperm and in seminal plasma.

Lipocalin-type prostaglandin D synthase (L-PGDS) is localized in Leydig cells, sperm, and epithelial cells of the epididymis. The present study was to determine the correlation between content of this enzyme in seminal plasma and on the surface of sperm. We analyzed 90 semen samples. L-PGDS in seminal plasma was analyzed by an ELISA procedure. L-PGDS on sperm was analyzed by flow cytometry. The semen donors were categorized in three groups: normal, oligospermic, and azoospermic. According to results obtained, L-PGDS may have the ability to improve progressive motility of sperm, and L-PGDS in seminal plasma and on sperm surface may impact male fertility in the female reproductive tract.

Different expression of lipocalin-type prostaglandin D synthase in rat epididymidis.

This study was designed to explore the different expression of L-PGDS (lipocalin-type prostaglandin D synthase) in rat epididymidis and to gain further insight into the potential function of L-PGDS in male reproduction. The expression of L-PGDS in rat epididymidis was assessed using real-time quantitative PCR and immunoblotting. The distribution of L-PGDS in rat epididymidis was explored by immunohistochemical methods. The result of immunohistochemistry displayed that L-PGDS was mainly distributed in epididymidis and localized within the cytoplasm and the cilia of the epithelial cells. Real-time quantitative PCR and immunoblotting showed that L-PGDS was strikingly expressed in the caput epididymidis, while a moderate to weak expression was observed in the corpus and cauda epididymidis, the level of mRNA was 0.52+/-0.02 in the caput, 0.48+/-0.03 in the corpus and 0.32+/-0.01 in the cauda epididymidis, the level of protein expression in caput, corpus and the cauda groups was 1, 0.89+/-0.03 and 0.62+/-0.01, which suggested that L-PGDS may play certain kind of role during the process of the spermatozoa maturation.