Morphologic and functional analysis of sperm and testes in Aquaporin 7 knockout mice

Sohara, Eisei; Ueda, Otoya; Tachibe, Takanori; Hani, Toshio; Jishage, Kou-ichi; Rai, Tatemitsu; Sasaki, Sei; Uchida, Shinichi

doi:10.1016/j.fertnstert.2006.07.1522

Cited by 48 publications

(33 citation statements)

References 23 publications

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“…This is clearly shown by findings from several studies that knockout mice for individual AQPs such as AQP 1, AQP 7, or AQP 9 seem to have little effect on fertility in homozygotes (Zhou et al 2001;Rojek et al 2007;Sohara et al 2007). AQP 11 knockout mice have been difficult to assess in this regard because they die progressively from 10 days to 2 months, making fertility estimates unreliable (Morishita et al 2004(Morishita et al ,2005.…”

Section: Discussionmentioning

confidence: 99%

Membrane Domain Specificity in the Spatial Distribution of Aquaporins 5, 7, 9, and 11 in Efferent Ducts and Epididymis of Rats

Hermo

Schellenberg

Liu

et al. 2008

J Histochem Cytochem.

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S U M M A R Y Water content within the epididymis of the male reproductive system is stringently regulated to promote sperm maturation. Several members of the aquaporin (AQP) family of water channel-forming integral membrane proteins have been identified in epididymal cells, but expression profiling for this epithelium is presently incomplete, and no AQP isoform has yet been identified on basolateral plasma membranes of these cells. In this study, we explored AQP expression by RT-PCR and light microscopy immunolocalizations using peroxidase and wide-field fluorescence techniques. The results indicate that several AQPs are coexpressed in the epididymis including AQP 5, 7, 9, and 11. Immunolocalizations suggested complex patterns in the spatial distribution of these AQPs. In principal cells, AQP 9 and 11 were present mainly on microvilli, whereas AQP 7 was localized primarily to lateral and then to basal plasma membranes in a region-specific manner. AQP 5 was also expressed regionally but was associated with membranes of endosomes. Additionally, AQPs were expressed by some but not all basal (AQP 7 and 11), clear (AQP 7 and 9), and halo (AQP 7 and 11) cells. These findings indicate unique associations of AQPs with specific membrane domains in a cell type-and region-specific manner within the epididymis of adult animals.

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Section: Discussionmentioning

confidence: 99%

Membrane Domain Specificity in the Spatial Distribution of Aquaporins 5, 7, 9, and 11 in Efferent Ducts and Epididymis of Rats

Hermo

Schellenberg

Liu

et al. 2008

J Histochem Cytochem.

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“…However, this assigned significance in spermiogenesis cannot be substantiated by the Aqp7 −/− mice, which show only a mild phenotype with normal testicular and epididymal morphology [72], normal testicular weight, normal daily sperm production, normal sperm morphological and kinematic characteristics, as well as in vitro and in vivo fertility [73]. Aqp7 −/− epididymal spermatozoa also have normal cell volume and are capable of water influx and efflux [62].…”

Section: Aqp7mentioning

confidence: 99%

Aquaporins in spermatozoa and testicular germ cells: identification and potential role

Yeung¹

2010

Asian J Androl

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Mammalian spermatozoa have relatively high water permeability and swell readily, as in the hypo-osmotic swelling test used in the andrology clinic. Physiologically, spermatozoa experience changes in the osmolality of the surrounding fluids in both the male and the female tracts on their journey from the testis to the ovum. Sperm volume regulation in response to such osmotic challenges is important to maintain a stable cell size for the normal shape and function of the sperm tail. Alongside ion channels for the fluxes of osmolytes, water channels would be crucial for sperm volume regulation. In contrast to the deep knowledge and numerous studies on somatic cell aquaporins (AQPs), the understanding of sperm AQPs is limited. Among the 13 AQPs, convincing evidence for their presence in spermatozoa has been confined to AQP7, AQP8 and AQP11. Overall, current findings indicate a major role of AQP8 in water influx and efflux for sperm volume regulation, which is required for natural fertilization. The preliminary data suggestive of a role for AQP7 in sperm glycerol metabolism needs further substantiation. The association of AQP11 with the residual cytoplasm of elongated spermatids and the distal tail of spermatozoa supports the hypothesis of more than just a role in conferring water permeability and also in the turnover and recycling of surplus cellular components made redundant during spermiogenesis and spermiation. This would be crucial for the maintenance of a germinal epithelium functioning efficiently in the production of spermatozoa.

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“…Another clue that seems to confirm this relationship is the diffuse, weak AQP7 labeling observed in the sperm with serious morphological alterations, such as dysplasia of the fibrous sheath concomitant with abnormalities of head-neck attachment. Although a role of AQP7 in sperm motility cannot be ruled out [Saito et al 2004; and its relationship with sperm modeling appears to be possible, it should be considered that AQP7 knockout mice showed normal sperm and fertility [Sohara et al 2007] and that a subject homozygous for a nonfunctional mutation of AQP7 has been reported as fertile [Kondo et al 2002], probably excluding an indispensable function of AQP7 in the regulation of fertility.…”

Section: E Moretti Et Almentioning

confidence: 99%

Immunolocalization of aquaporin 7 in human sperm and its relationship with semen parameters

Moretti

Terzuoli²,

Mazzi³

et al. 2011

Systems Biology in Reproductive Medicine

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Aquaporins (AQPs) are a family of 13 small hydrophobic transmembrane proteins expressed in numerous tissues and cells. Some AQPs work as strict water channels, others are permeable to a range of substances, including glycerol. In the male reproductive system their localization in testis, efferent ducts, epididymis, and spermatozoa has been described. We studied the distribution of AQP7 in ejaculated human sperm and the relationship between AQP7 labeling and sperm characteristics. Semen samples from 33 men were examined by light and transmission electron microscopy (TEM). TEM data were quantified using a mathematical formula that calculates a fertility index (FI) and the percentages of sperm apoptosis, immaturity, and necrosis. Immunocytochemistry with a polyclonal antibody anti-AQP7 was performed on the sperm samples. Normal sperm were labeled in the pericentriolar area, midpiece, equatorial segment, and weakly in the tail (grade 1). Abnormal sperm showed a diffuse low intensity of fluorescence evident in the cytoplasmic residues, coiled tails, in the entire head, and acrosome (grade 2). A high number of motile sperm obtained by swim up were labeled in a dotted manner in the mitochondria. A significant positive correlation was found between the spermatozoa with AQP7 grade 1 labeling and the percentage of normal form (P < 0.008), progressive motility and FI (P < 0.005); a negative correlation was noted with the percentages of cytoplasmic residues (P < 0.010) and immaturity (P < 0.006) and coiled tails (P < 0.012). The link between AQP7 distribution and sperm morphology and the particular dotted labeling in swim up selected motile sperm are novel and deserve additional studies.

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Morphologic and functional analysis of sperm and testes in Aquaporin 7 knockout mice

Cited by 48 publications

References 23 publications

Membrane Domain Specificity in the Spatial Distribution of Aquaporins 5, 7, 9, and 11 in Efferent Ducts and Epididymis of Rats

Membrane Domain Specificity in the Spatial Distribution of Aquaporins 5, 7, 9, and 11 in Efferent Ducts and Epididymis of Rats

Aquaporins in spermatozoa and testicular germ cells: identification and potential role

Immunolocalization of aquaporin 7 in human sperm and its relationship with semen parameters

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