Isolation and biochemical characterization of the human sperm tail fibrous sheath.

The isolation and biochemical characterization of the human sperm tail fibrous sheath (FS) is described for the first time. Initially, the solubilization properties of the FS were assessed immunocytochemically using GDA-J/F3 and RT97 monoclonal antibodies (MoAbs) and morphologically by electron microscopy. Following extensive investigations to optimize the conditions for the FS isolation, a simple method was developed which involved sequential extraction of the flageller components with Triton-dithiothreitol (DTT) and urea-DTT. The procedure was monitored by phase contrast microscopy and the purity of the FS preparations was confirmed by electron microscopy. SDS-PAGE of the isolated FS revealed seven major protein bands with mol. wt of 97, 76, 62, 55, 33, 28 and 25 kDa. In Western blotting, the reaction of RT97 MoAb with supernatants from the various extraction steps and the isolated FS indicated that its target antigen (AJ-p97) was an integral FS product and that disulphide bonding was probably involved in its stabilization. The reactivity of normal and aprotruded sperm tails with GDA-J/F3 and RT97 MoAbs was not affected by Triton while the GDA-J/F3 staining of the cytoplasmic matrix of other abnormal spermatids was abolished, thus suggesting variation in the biochemical properties of GDA-J/F3 in normal and abnormal germ cells. These and other data indicate that the FS could be a modified form of intermediate filament.     

Human sperm tail fibrous sheath undergoes phosphorylation during its development.

The phosphorylation of the human sperm tail fibrous sheath as a maturational step during its development is reported for the first time. This was demonstrated using GDA-J/F3 and RT97 monoclonal antibodies (MoAb) which recognize the fibrous sheath. In indirect immunofluorescence microscopy of frozen sections of human adult testes, the two antibodies reacted with the assembled fibrous sheath only, but the numbers of sperm tails stained with RT97 were consistently lower than those treated with GDA-J/F3. Furthermore, by using double indirect immunofluorescence, although the majority of spermatozoa were doubly stained with the two MoAbs, some GDA-J/F3-positive sperm tails were negative with RT97. In epididymal and ejaculated spermatozoa, the two antibodies stained all the tails. This indicated that the ontogenic appearance of the GDA-J/F3 epitope precedes that of RT97. In Western blotting and/or indirect immunofluorescence of spermatozoa, treatment of samples with alkaline phosphatase abolished the reactivity of RT97 while that of GDA-J/F3 MoAb was not affected. This finding indicated that the RT97 but not the GDA-J/F3 epitope was phosphorylated. Together, these results therefore reveal that during tail morphogenesis, the fibrous sheath undergoes phosphorylation as part of its structural maturation. Screening of sperm cell precursors recovered from oligozoospermic donors showed reaction of some abnormal germ cells with GDA-J/F3 MoAb but not with RT97, suggesting the possible failure of phosphorylation of the fibrous sheath protein in these cells. The significance of these findings is discussed together with the biological importance of phosphorylation to the fibrous sheath.     

Immunology: AJ-FS9 monoclonal antibody detects masked antigens within the human sperm tail fibrous sheath

AJ-FS9 is one of a new series of monoclonal antibodies (mAbs)raised by immunizing mice with isolated human sperm tail fibroussheath (FS). Using indirect immunofluorescence (IIF) of humanspermatozoa dried onto slides, the AJ-FS9 mAb reacted with theprincipal piece of occasional spermatozoa. Following their enzymatictreatment with trypsin, dispase or collagenase, but not sulphatase,all the spermatozoa were stained at their principal piece. Theultrastructural localization of the antigens to the FS was establishedby immunogold electron microscopy, which showed the distributionof gold particles on the FS outer surface of spermatozoa sequentiallytreated with 1% Triton and dispase; spermatozoa demembranatedby Triton alone showed no reaction. For biochemical characterization,spermatozoa were lysed with 1% Triton, and the sperm pelietwas run through a reducing sodium dodecyl sulphate-polyacrylamidegel electrophoreesis, Western blotted and immunostained withAJ-FS9. The results showed the reaction of the antibody withthree protein bands with molecular masses ranging between 46and 56 kDa. IIF screening of human testicular cryostat sectionswith AJ-FS9 mAb showed its reactivity with occasional spermtails; but following their dispase treatment, all spermatozoawere stained. The restricted staining of the assembled FS ofmaturing sperm tails indicated the late appearance of the antigensduring spermatogenesis. The antibody did not react with spermcell precursors or other cell types within/without the seminiferoustubules. Untreated and dispase-treated frozen sections of skin,oesophagus, tongue, liver, kidney, stomach, ileum or their bloodvessels showed no reaction. These data provide the first evidencefor the presence of masked antigens within the human sperm tailFS, and their significance is discussed.     

AJ-FSI monoclonal antibody detects a novel group of non-glycostlated antigens within the human sperm tail fibrous sheath

AJ-FS1 is one of a new series of monoclonal antibodies (MoAbs)raised by immunizing mice with isolated human sperm tail fibroussheath. Usinjg indirect immunofluorescence (IIF), the AJ-FS1MoAb didnot react with the surface antigens of viable sperm,but didstain the falgellar principal piece of sperm dried ontoslides or those demenbranated with 1% Triton X-100. The specificityof the antibody for the fibrous sheatht was confirmed by immunogoldelectron microscopy which showed the distrobution of gold particleson the outer fibrous sheath surface, and its reaction with theWestern blots of purified fibrous sheath preparations wheremultiple protein bands with mol. wt ranging between 97 and 28kDa were identified. The same peptides were alsod detected inurea-dithiothreitol (DTT) fraction of sequentially extractedspermatozoa but not in Triton or Triton-DTT sperm lysates. Thefailure of sodium metaperiodate to abrogate the antobody reactionin both Western blotting and IIf indicated on the non-glycosylatednature of the antigens. IIF screening of human testicular cryosatatsections with AJ-FS1 MoAb showed its reactivity with the assembledfibrous sheath of maturing sperm tails only; thus indicatingthe late apperance of the antigens during spermatogensis. Theanti-body did not react with skin, oesophagus, tongue, liver,kidney, placenta, uterus, cervix or their blood vessels. Thesignificance of these results is discussedtogether with theimportnce of AJ-FS1 MoAb as a specific probe for the characterizationof the fibrous sheath antigens in both normal and abnormal falgella.     

GDA-J/F3 monoclonal antibody as a novel probe for the human sperm tail fibrous sheath and its anomalies

GDA-J/F3 monoclonal antibody (MoAb) recognized an antigen in the fibrous sheath (FS) of human spermatozoa. This was based on: (i) intracellular localization of the antigen which was limited to the principal piece of the sperm tail; (ii) its absence from the cilia of trachea and nasal mucosa which lack FS; (iii) immunogold electron microscopy (IEM) which confirmed its ultrastructural localization to the FS. The antibody was used for the detection of abnormal germ cells in human semen. Nucleated cells other than spermatozoa (NCOS) obtained from oligozoospermic donors were screened with GDA-J/F3 MoAb using the indirect immunofluorescence test. The antibody which stains only the tails in normal cells, produced diffuse cytoplasmic immunofluorescence inside some spermatids. Using phase contrast microscopy, the tails in these spermatids were either present or undetectable. Electron microscopy studies of the NCOS showed the lack of the FS in those which had the tails (afibrous tail), or the presence of disorganized tails (tail dysgenesis) in the others. This antibody therefore provides a useful analytical tool for probing the FS as well as for the easy identification of certain abnormal germ cells in human semen.     

Incidence of tail structure distortions associated with dysplasia of the fibrous sheath in human spermatozoa

Dysplasia of the fibrous sheath (DFS) is an anomaly found in spermatozoa of severe asthenozoospermic patients. Marked hypertrophy and hyperplasia of the fibrous sheath is the common characteristic. Immunocytochemistry allowed us to visualize the distortions and incidence of tail structure abnormalities associated with this phenotype in six patients; four with a complete form and two with an incomplete form of this pathology previously diagnosed and studied by electron microscopy. Microtubules and fibrous sheaths were studied using monoclonal antibodies against alpha-acetylated tubulin and anti-FSC1 (the major protein component of the fibrous sheath). Mitochondrial sheaths were visualized using the mitochondrion-specific vital dye MitoTracker green FM(TM). Phase contrast and fluorescent microscopy of semen samples showed large numbers of spermatozoa with short, rigid, thick and irregular tails. As expected, anomalous and completely distorted fibrous sheaths, severe alterations of the axonemal microtubules and different patterns of mitochondrial sheath configurations were found. While ultrastructural studies of thin sections allow an in-depth knowledge of the internal organization of the sperm tail, fluorescence labelling of selected sperm components affords a unique view of the whole flagellum including topographical relationships of various organelles. The combination of these different approaches is essential for a comprehensive understanding of this particular pathology.     

The target antigen for GDA-J/F3 monoclonal antibody in the human sperm tail fibrous sheath is a non-collagenous asialo-glycoprotein: implications and significance

Enzymes and chemicals were used to analyse the biochemical structureof the antigenic epitope recognized by GDA-J/3 monoclonal antibody(MoAb) in the human sperm tail fibrous sheath. Treatment ofsperm dried onto slides with trypsin or dispase enzymes abolishedtheir immunofluorescence staining with GDA-J%3 MoAb, thus indicatingthe proteinaceous nature of the antigen. The proteolytic cleavageof GDA-J%F3 protein by trypsin, which also caused sperm decapitation,indicated the presence of peptide bonds involving the carboxylgroups of the basic amino acids, arginine and%or lysine. Theepitope was also glycosylated as demonstrated by its sensitivityto sodium metaperiodate treatment which was dose–dependent.The GDA-J%F3 antigenic epitope lacked sialic acid since pre–treatmentof spermatozoa with sialidase enzyme (neur–aminidase)had no effect on their reactivity with the antibody. The lackof collagenous domains in the GDA-J%F3 antigen was demonstratedby the failure of collagenase to abrogate sperm immunostainingwith the MoAb. Furthermore, type VII collagen of the skin basementmembrane (BM) was previously thought of as a potential targetantigen for GDA-J%F3 MoAb. This was ruled out since severalmonoclonal and polyclonal antibodies failed to detect the antigenin the spermatozoa using immunofluorescence and Western blotting.These data, therefore, show that the target antigen for GDA-J%F3MoAb is a non-collagenous asialo–glycoprotein, and byinference provide the first evidence for the glycosylation ofthe sheath proteins as another step of post–translationalmodification occurring during sperm tail development.     

Sperm protein 17 is expressed in the sperm fibrous sheath

Background

Sperm protein 17 (Sp17) is a highly conserved mammalian protein characterized in rabbit, mouse, monkey, baboon, macaque, human testis and spermatozoa. mRNA encoding Sp17 has been detected in a range of murine and human somatic tissues. It was also recognized in two myeloma cell lines and in neoplastic cells from patients with multiple myeloma and ovarian carcinoma. These data all indicate that Sp17 is widely distributed in humans, expressed not only in germinal cells and in a variety of somatic tissues, but also in neoplastic cells of unrelated origin.

Methods

Sp17 expression was analyzed by immunocytochemistry and transmission electron microscopy on spermatozoa.

Results

Here, we demonstrate the ultrastructural localization of human Sp17 throughout the spermatozoa flagellar fibrous sheath, and its presence in spermatozoa during in vitro states from their ejaculation to the oocyte fertilization.

Conclusion

These findings suggest a possible role of Sp17 in regulating sperm maturation, capacitation, acrosomal reaction and interactions with the oocyte zona pellucida during the fertilization process. Further, the high degree of sequence conservation throughout its N-terminal half, and the presence of an A-kinase anchoring protein (AKAP)-binding motif within this region, suggest that Sp17 might play a regulatory role in a protein kinase A-independent AKAP complex in both germinal and somatic cells.     

Gene deletions in an infertile man with sperm fibrous sheath dysplasia

BACKGROUND: Asthenozoospermia may sometimes be related to geneticstructural defects of the sperm tail detectable by transmissionelectron microscopy. Dysplasia of the fibrous sheath (DFS) isa genetic sperm defect, characterized by dysplastic developmentof the axonemal and periaxonemal cytoskeleton. We report thecase of an infertile man with normal sperm count and total spermimmotility in which dysplasia of the fibrous sheath, Akap3,Akap4 gene deletions, meiotic segregation of chromosomes 18,X and Y and Y microdeletions were investigated. METHODS: A 32-year-oldman with a 3-year history of primary infertility presented atour Regional Referral Center for Male Infertility. Family medicalhistory, lymphocyte karyotype, PCR analysis, physical examination,hormone assays and semen analysis were performed. RESULTS: Ultrastructuralsperm evaluation showed dysplasia of the fibrous sheath. Immunostainingof AKAP4 protein was negative in sperm tails. PCR analysis revealedintragenic deletions of the Akap3 and Akap4 genes. Fluorescencein situ hybridization on sperm showed a high frequency of XYdisomy. CONCLUSION: In this infertile patient, our results suggesta possible relationship between dysplasia of the fibrous sheath,partial deletions in the Akap3 and Akap4 genes and absence ofAKAP4 protein in the fibrous sheath. These findings, however,were not detected in another four patients with dysplasia ofthe fibrous sheath. Our results require future confirmatorymolecular analyses.     

Relationship between sperm motility and the processing and tyrosine phosphorylation of two human sperm fibrous sheath proteins, pro-hAKAP82 and hAKAP82.

Sperm motility is regulated by the cAMP-dependent protein kinase (protein kinase-A)-mediated phosphorylation of a group of largely unidentified flagellar proteins. Human AKAP82 (hAKAP82) and its precursor protein, pro-hAKAP82, are members of the A-kinase anchor protein (AKAP) family. These proteins tether protein kinase-A to the fibrous sheath of human spermatozoa and presumably localize the activity of the kinase near specific targets in the sperm flagellum. In this way, pro-hAKAP82 and hAKAP82 may be involved in regulating sperm motility. Similar to its homologues in other species, pro-hAKAP82 is proteolytically processed to hAKAP82. However, the amount of processing of pro-hAKAP82 in human spermatozoa is less than the amount of processing of the precursor in other species. We postulated that this lower extent of processing may be related to lower percentages of human sperm motility. In addition, both pro-hAKAP82 and hAKAP82 are tyrosine phosphorylated in a capacitation-dependent manner. Since capacitation is associated with hyperactivated motility, we postulated that tyrosine phosphorylation of pro-hAKAP82/hAKAP82 is associated with changes in motility. However, using a combination of immunofluorescence and immunoblotting approaches, we found no evidence for an association between either processing or tyrosine phosphorylation of pro-hAKAP82/hAKAP82 and significant differences in motility in spermatozoa from normal men.     

Isolation and characterization of rabbit single chain antibodies to human Reg Ialpha protein

To investigate the role of Reg Ialpha in human inflammatory bowel disease (IBD), we made two phage-displayed single chain variable fragment (scFv) libraries from rabbits immunized with recombinant or native human Reg Ialpha. After one to three rounds of panning, we were able to isolate phage-displaying scFvs, which bound to human Reg Ialpha. Anti-Reg Ialpha scFvs from both libraries showed similar immunoreactivity to different processed forms of the protein. Despite several DNA fingerprint patterns among these clones, their deduced amino acid sequences are highly homologous with 100% identity in the complementarity-determining regions (CDRs) of the variable segment of heavy chain (VH) region and a small variation in the CDR1 of the variable segment of light chain (VL) region. We also expressed and purified soluble myc-tagged or glutathione S-transferase (GST) fusion scFv proteins from bacteria. Immunohistochemical studies using one of our anti-Reg Ialpha scFv antibodies showed prominent staining in the metaplastic Paneth cell population and light staining in the lamina propria. This scFv antibody is now being used for studies of the role of Reg Ialpha in human IBD.     

Cloning and characterization of a novel sperm tail protein, NYD-SP28

In this study, a gene coding a novel human sperm tail protein named NYD-SP28 was cloned and characterized using a complementary DNA (cDNA) microarray. Its expression was 3.5 times higher in human testis than in fetal testis, and very high in human spermatozoa. The full length of NYD-SP28 cDNA was 1798 bp and encoded a 484-amino-acid protein. Motif analysis revealed that the protein contained a cluster of phosphorylation sites, N-glycosylation sites and N-myristoylation sites. Immunohistochemical analysis of normal human testes showed that NYD-SP28 was expressed in the cytoplasm of spermatogenic cells but not in interstitial cells. The EGFP-NYD-SP28 fusion protein was also localized in the cytoplasm of transfected 7721 cells. In human spermatozoa, NYD-SP28 immunoreactivity was detected in entire sperm tail. Using the two-dimensional (2-D) gel electrophoresis and immunoblotting technique, NYD-SP28 was found to be post-translationally modified during sperm capacitation. In conclusion, these results suggest that NYD-SP28 is a new human sperm tail protein and might play an important role during sperm capacitation.     

Isolation and biological characterization of boar sperm capacitation-related antigen

PROBLEM: Monoclonal anti-capacitated sperm antibody has been used as a probe to identify, isolate, and characterize specific, fertilization-related antigen with some characteristic features that point to its possible significance in immunocontraception. METHOD OF STUDY: Fast protein liquid chromatography (FPLC), enzyme-linked immunosorbent assay (ELISA), sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), and isoelectrofocusing were used for isolation, immunochemical and physicochemical characterization of a monoclonal antibody (mAb) 1F10 cognate antigen. Sperm-zona pellucida binding and hemizona assay were used for testing the biological roles of mAb 1F10 and Ag 1F10 in boar and human fertilization processes. RESULTS: The Ag 1F10 was found to be eluted in the eighth protein peak of FPLC-fractionated Nonidet P40 (NP40) extracts of capacitated boar spermatozoa. The SDS-PAGE and immunoelectrofocusing experiments showed that Ag 1F10 is a protein composed of a single peptide chain with a relative molecular mass of 68/70 kDa and an isoelectric point of 3.5. It was demonstrated that the zona binding activity of spermatozoa preincubated in the presence of mAb 1F10 was significantly inhibited both in porcine and human in vitro fertilization (IVF) systems. A dose-dependent manner of inhibition of the sperm/ligand activities of porcine and human zona pellucida was observed when the effect of purified Ag 1F10 was investigated by its preincubation with zona pellucida. CONCLUSIONS: It is assumed that the protein bearing the epitope recognized by mAb 1F10 may be accepted as one of the molecules with receptor function in sperm-zona pellucida interaction during fertilization.     

Molecular cloning and characterization of the human orthologue of the oppo 1 gene encoding a sperm tail protein

We report here the molecular cloning and characterization of a human orthologue of oppo 1, a mouse gene encoding a male germ-cell-specific sperm tail protein, and the organization of its genomic structure. The mRNA of the human oppo 1 gene (h-oppo 1) was expressed exclusively in the testis, and the 30 kDa protein encoded by the mRNA was detected in human testis and sperm. Immunohistochemical analyses showed that human OPPO 1 protein was localized in the flagellae of ejaculated sperm. A human genomic DNA database search indicated that the h-oppo 1 gene mapped to chromosome 17. The genomic structure of h-oppo 1 showed differences in exon/intron usage, the sequence of the 5'-flanking region, and the first intron was rich in Alu repeats as compared with the mouse oppo 1 gene. Comparison of the two genomic sequences indicated that human oppo 1 has evolved independently, resulting in substantial differences in the genomic structure after the human-mouse split, whereas the sequence of the basic functional unit of the oppo 1 gene seems to have been relatively well conserved.     

Isolation and characterization of newborn rabbit brain-derived microglia

We isolated brain microglia from newborn rabbits and maintained these cells in in vitro culture. Enriched populations of rabbit microglia share several characteristics of mononuclear phagocytes including intracellular staining for nonspecific esterase and acid phosphatase. Microglia express Fc receptors, generate superoxide anion, and stain positive with the lectin Ricinus communis. Rabbit brain microglia develop multinucleated giant cells and small colonies in in vitro culture. The cells are highly phagocytic in culture. Other investigators have recently demonstrated that rabbits can be infected with HIV-1 in vivo and that neurological symptoms occur only when HIV-1 infection was carried out in HTLV-1-infected rabbits. Brain microglia most likely play a central role in HIV-1 encephalopathy. The availability of rabbit brain microglia in in vitro culture, offers a valuable potential cell model to study HIV-1 infection in the central nervous system.     

Isolation and characterization of a rabbit adrenal autoantigen

The antigenic components of adrenal extract were fractionated by chromatography on DEAE-cellulose. Using a stepwise elution procedure, it was found that a componenet of major interest, termed Pk3b, was eluted by a buffer of pH 6.70 and 0.09 M in phosphate-chloride. This antigenic preparation reacted with several rabbit antisera that had been prepared by isoimmunization with rabbit adrenal homogenate, in contrast to several other fractions, which reacted with only one (or two) of the antisera. Pk3b also showed a high degree of homogeneity, as shown by immunodiffusion, paper electrophoresis, and analytical ultracentrifugation. By the latter technique, an extrapolated sedimentation coefficient of 4.45S was determined. The further comparison of this antigen in immunodiffusion, along with an antiserum and the adrenal extract from the antiserum-providing animal, confirmed again that this is an autoantigen, and that it is one of five autoantigens of the adrenal gland.     

兔肌源性干细胞的生物学特性及表型研究

目的:探讨兔肌源性干细胞(MDSCs)的分离及特征和表型研究。方法:取1.5月龄新西兰兔大腿肌肉，采用差速贴壁分离Preplate技术，分别用Ⅺ胶原酶、dispase蛋白酶以及胰蛋白酶分步消化肌肉，并用差速贴壁法分离晚期贴壁的细胞，流式细胞仪(FCM)、免疫细胞化学以及Western blotting等检测初步确定细胞表型。结果:进行连续6 d的差速贴壁分离。第3 d开始得到较多量的圆形或短梭形细胞，簇样生长，体积明显小于骨骼肌细胞及其它杂细胞，10 d左右汇合，有极强的融合生长倾向。细胞在汇合度<30%传代可较好地保持原形态，流式细胞仪检测示MDSCs>80%为desmin+，>70%为Bcl-2+，>95%为CD45-，免疫细胞化学定性示desmin+。Western blotting检测显示随着细胞的纯化，α-SMA表达越来越弱。而细胞高汇合度(>50%)或低血清培养时极易融合成肌管或肌细胞链，skeletal myosin+。结论:MDSCs具有desmin、Bcl-2高水平表达和CD45极低水平表达的特性，具有多向分化能力的MDSCs是组织工程研究的一种新型种子细胞。     

Successful intracytoplasmic sperm injection with spermatozoa from a patient with dysplasia of the fibrous sheath and chronic respiratory disease

The present report describes a successful intracytoplasmic sperm injection (ICSI) procedure performed with immotile spermatozoa from a young man with a combination of dysplasia of the fibrous sheath and dynein deficiency, a recently described variant of the immotile cilia syndrome. This methodology provides the only suitable solution for these patients in whom all other assisted fertilization technologies have previously failed, and opens the possibilities for treatment of male infertility due to severe, irreversible sperm defects such as the one reported here.