|LETTER TO THE EDITOR
|Year : 2014 | Volume
| Issue : 6 | Page : 927-928
Immunodetection of Tau microtubule-associated protein in human sperm and testis
Julien Sigala1, Fanny Jumeau1, Marie-Laure Caillet-Boudin2, Nicolas Sergeant2, Caroline Ballot3, Jean-Marc Rigot4, François Marcelli5, Meryem Tardivel6, Luc Buée2, Valérie Mitchell3
1 EA 4308 Gamétogenèse et Qualité du Gamète, Institut de Biologie de la Reproduction-Spermiologie-CECOS, Hôpital Jeanne de Flandre, Centre Hospitalier Régional Universitaire de Lille; INSERM U837 Alzheimer et Tauopathies, Place de Verdun, Lille, France
2 INSERM U837 Alzheimer et Tauopathies, Place de Verdun, Lille, France
3 EA 4308 Gamétogenèse et Qualité du Gamète, Institut de Biologie de la Reproduction-Spermiologie-CECOS, Hôpital Jeanne de Flandre, Centre Hospitalier Régional Universitaire de Lille, Lille, France
4 EA 4308 Gamétogenèse et Qualité du Gamète, Institut de Biologie de la Reproduction-Spermiologie-CECOS, Hôpital Jeanne de Flandre, Centre Hospitalier Régional Universitaire de Lille; Département d'Andrologie, Hôpital Calmette, Lille, France
5 Département d'Andrologie, Hôpital Calmette, Lille, France
6 BICeL Université Lille Nord de France-Centre Hospitalier Régional Universitaire de Lille-IFR114, Lille, France
|Date of Submission||10-Apr-2014|
|Date of Decision||16-May-2014|
|Date of Acceptance||29-May-2014|
|Date of Web Publication||02-Sep-2014|
EA 4308 Gamétogenèse et Qualité du Gamète, Institut de Biologie de la Reproduction-Spermiologie-CECOS, Hôpital Jeanne de Flandre, Centre Hospitalier Régional Universitaire de Lille, Lille
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Sigala J, Jumeau F, Caillet-Boudin ML, Sergeant N, Ballot C, Rigot JM, Marcelli F, Tardivel M, Buée L, Mitchell V. Immunodetection of Tau microtubule-associated protein in human sperm and testis. Asian J Androl 2014;16:927-8
|How to cite this URL:|
Sigala J, Jumeau F, Caillet-Boudin ML, Sergeant N, Ballot C, Rigot JM, Marcelli F, Tardivel M, Buée L, Mitchell V. Immunodetection of Tau microtubule-associated protein in human sperm and testis. Asian J Androl [serial online] 2014 [cited 2020 Feb 23];16:927-8. Available from: http://www.ajandrology.com/text.asp?2014/16/6/927/136446 - DOI: 10.4103/1008-682X.136446
Luc Buée, Valérie Mitchell.
These two authors contributed equally to this research.
The cytosolic protein Tau is naturally present in human neurons, where it has a pivotal role in controlling microtubule stability.  Hyperphosphorylation of Tau (observed during neurodegenerative diseases, such as Alzheimer's disease) impairs the protein's ability to bind microtubules. This results in microtubule disassembly and the formation of Tau aggregates. , Tau protein is also widely expressed in peripheral tissues.  In the male reproductive system, screening for Tau has focused solely on the rodent and bovine testis. , In the present study, we used immunofluorescence and immunoenzymatic techniques (with a Tau-specific antibody)  to investigate the presence of Tau protein in human ejaculated sperm and testicular tissue. We studied (i) five semen samples from normozoospermic men and (ii) testicular biopsies taken from two men suffering from obstructive azoospermia (in whom spermatogenesis was normal). The men were recruited by our university hospital's andrology clinic, and all provided their written, informed consent to participation. Briefly, washed, smeared sperm samples were incubated with normal goat serum and then with rabbit anti-C-terminus Tau antibody raised against synthetic peptides encoding the last 15 amino acids of Tau protein (dilution: 1:1000). The slides were revealed with Alexa 488-conjugated goat anti-rabbit antibodies (Molecular Probes;, Invitrogen SARL, Cergy Pontoise, France). Dewaxed 5 μm paraffin sections were microwaved and incubated with normal sheep or goat serum and then with rabbit anti-C-terminus Tau antibody (dilution: 1:1000). In immunoenzymatic experiments, the sections were revealed with a biotinylated sheep anti-rabbit immunoglobulin G (dilution: 1:150) and then an avidin/biotinylated horseradish peroxidase complex (both from Vector Laboratories, AbCys, Paris, France). In immunofluorescence experiments, the sections were revealed with fluorescent goat anti-rabbit Alexa 568 (Molecular Probes;, Invitrogen SARL, Cergy Pontoise, France). After further washing, the slides were coverslipped using Vectashield mounting medium for fluorescence with DAPI (Vector Laboratories, AbCys). In control experiments, the primary antibody was omitted. The slides were observed, and images were acquired with a confocal LSM710 microscope and an Axioplan microscope (both from Zeiss, Gφttingen, Germany).
Tau immunostaining was detected in all smeared spermatozoa ([Figure 1]a). The Tau protein was located in the sperm midpiece. In testicular tissue, Tau immunoreactivity was observed in both spermatocytes and spermatids ([Figure 1]b). In spermatocytes, cytoplasmic fluorescent dots were located all around the nucleus ([Figure 1]c). In elongated spermatids, the immunolabeled zone was situated behind the nucleus ([Figure 1]d). No staining was observed in spermatozoa or in tissue sections of control samples lacking primary antibody ([Figure 1]e and f).
|Figure 1: Micrographs of human ejaculated sperm and testicular tissue treated with anti-Tau antibody ( a - d ) and controls ( e and f ). ( a ) In spermatozoa, fluorescent Tau labelling is observed in the midpiece. ( b ) In testicular tissue, Tau immunoreactivity is observed in both spermatocytes and spermatids. ( c ) In spermatocytes, cytoplasmic fluorescent dots are located all around the nucleus. ( d ) In elongated spermatids, the immunolabelled zone is located behind the nucleus.|
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Over the last decades, few researchers have studied the presence of Tau protein in the reproductive tract. Two eminent, early studies reported the presence of Tau protein in the rodent and bovine testis. , In human germ cells and spermatozoa, Tau may be involved in the regulation of microtubule proteins. The spermatozoon's main microtubule-organizing centre is the centrosome complex. It has a role in sperm and zygote aster formation, and the development of the bipolar mitotic apparatus.  Dysfunction of the centrosome complex will result in developmental abnormalities after fertilization. The epithelium of seminiferous tubules has a vast network of microtubules (particularly within the manchette, the axoneme, and the mitotic and meiotic spindles of germ cells).  The presence of Tau in human testicular tissue suggests that this protein has a role in meiotic division in male germ cells and during their extension to spermatozoa. As has been suggested in the context of tauopathies,  the aggregation, hyperphosphorylation and/or ubiquination of Tau might impair sperm microtubule function and transport.
In summary, this study reports the immunoexpression of Tau microtubule-associated protein in human sperm and testis. We hypothesize that Tau is involved in the development of sperm in a man and thus may represent an additional parameter for sperm function in male fertility.
| Author Contributions|| |
JS carried out the immunohistochemistry and wrote the manuscript; FJ and CB participated in the design of the study; MLCB and NS revised the manuscript critically; JMR and FM participated in the retrieve of the testicular samples; MT performed the confocal microscopy analysis; LB and VM supervised the experiments. All authors read and approved the final manuscript.
| Competing Interests|| |
The authors declare no competing interests.
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