Androgen Receptor Expression in the Caput Epididymal Epithelium Is Essential for Development of the Initial Segment and Epididymal Spermatozoa Transit

Abstract The epididymis plays an essential role in male fertility, and disruption of epididymal function can lead to obstructive azoospermia. Formation and function of the epididymis is androgen-dependent. The androgen receptor (AR) is expressed in both the stromal and epithelial compartments of the epididymis, and androgen action mediated via stromal cells is vital for its normal development and function. However the impact of epithelial specific AR-dependent signaling in the epididymis remains underexplored. To address this, we used conditional gene-targeting in mice to selectively ablate AR from the caput epididymal epithelium, and characterized the resulting phenotype at multiple postnatal ages. Caput epithelium androgen receptor knock-out mice have normal serum testosterone concentrations at day (d) 21 and d100, but do not develop an epididymal initial segment. The remaining caput epithelium displays a significant decrease in epithelial cell height from d11 and lumen diameter from d21 and disruption of the smooth muscle layer of the caput epididymis at d100. From d21, caput epithelium androgen receptor knock-out mice accumulate cell debris, proteinaceous material, and, at later ages, spermatozoa in their efferent ducts, which prevents normal passage of spermatozoa from the testis into the cauda epididymis resulting in infertility when tested at d100. This efferent duct obstruction leads to fluid back-pressure and disruption of the seminiferous epithelium of the adult testis. We conclude that epithelial AR signaling is essential for postnatal development and function of the epididymal epithelium and that disruption of this signaling can contribute to obstructive azoospermia.

Download Full-text

Regulation of muscarinic receptor expression and function in cultured cells and in knock-out mice

Life Sciences ◽

10.1016/s0024-3205(97)00053-2 ◽

1997 ◽

Vol 60 (13-14) ◽

pp. 1101-1104 ◽

Cited By ~ 6

Author(s):

Lise A. McKinnon ◽

Marc Rosoff ◽

Susan E. Hamilton ◽

Michael L. Schlador ◽

Sarabeth L. Thomas ◽

...

Keyword(s):

Muscarinic Receptor ◽

Cultured Cells ◽

Receptor Expression ◽

Knock Out ◽

Knock Out Mice ◽

And Function

Download Full-text

Physiological Modulation of Intestinal Motility by Enteric Dopaminergic Neurons and the D2 Receptor: Analysis of Dopamine Receptor Expression, Location, Development, and Function in Wild-Type and Knock-Out Mice

Journal of Neuroscience ◽

10.1523/jneurosci.4720-05.2006 ◽

2006 ◽

Vol 26 (10) ◽

pp. 2798-2807 ◽

Cited By ~ 134

Author(s):

Z. S. Li

Keyword(s):

Dopamine Receptor ◽

Dopaminergic Neurons ◽

Intestinal Motility ◽

D2 Receptor ◽

Receptor Expression ◽

Wild Type ◽

Knock Out ◽

Knock Out Mice ◽

And Function

Download Full-text

Endothelial Tyrosine Kinase Tie1 Is Required for Normal Schlemm’s Canal Development

Arteriosclerosis Thrombosis and Vascular Biology ◽

10.1161/atvbaha.121.316692 ◽

2022 ◽

Author(s):

Jing Du ◽

Benjamin R. Thomson ◽

Tuncer Onay ◽

Susan E. Quaggin

Keyword(s):

Intraocular Pressure ◽

Quantitative Polymerase Chain Reaction ◽

Schlemm’S Canal ◽

Knock Out ◽

Schlemm's Canal ◽

Elevated Intraocular Pressure ◽

Knock Out Mice ◽

And Function ◽

The Impact

Background: Schlemm’s canal (SC) is a large vessel residing in the iridocorneal angle and is required to regulate aqueous humor outflow. Normal SC structure and function is indispensable for maintaining normal intraocular pressure, and elevated intraocular pressure is a risk factor for development of glaucoma. Recent reports have identified a key role of the angiopoietin-Tie2 pathway for SC development and function; however, the role of the orphan receptor Tie1 has not been clarified. Methods: We used Tie1 knock out mice to study the function of Tie1 in SC development and function. Real-time quantitative polymerase chain reaction and Western blot analyses were used to verify Tie1 deletion. High-resolution microscopy of mouse SC whole mount and cross sections were used to study SC morphology. Measurement of intraocular pressure in live mice was used to study the impact of Tie1 on SC function. Results: Tie1 is highly expressed in both human and mouse SC. Tie1 knock out mice display hypomorphic SC and elevated intraocular pressure as a result of attenuated SC development. Conclusions: Tie1 is indispensable for SC development and function, supporting it as a novel target for future SC-targeted glaucoma therapies and a candidate gene for glaucoma in humans.

Download Full-text

Targeted Inactivation of the Androgen Receptor Gene in Murine Proximal Epididymis Causes Epithelial Hypotrophy and Obstructive Azoospermia

Endocrinology ◽

10.1210/en.2010-0768 ◽

2011 ◽

Vol 152 (2) ◽

pp. 689-696 ◽

Cited By ~ 45

Author(s):

Anton Krutskikh ◽

Karel De Gendt ◽

Victoria Sharp ◽

Guido Verhoeven ◽

Matti Poutanen ◽

...

Keyword(s):

Androgen Receptor ◽

Initial Segment ◽

Receptor Gene ◽

Androgen Receptor Gene ◽

Obstructive Azoospermia ◽

Efferent Duct ◽

Duct Ligation ◽

Androgen Regulation ◽

And Function

Abstract The epithelial lining of the epididymal duct expresses the androgen receptor (Ar) along its entire length and undergoes rapid and profound degeneration when androgenic support is withdrawn. However, experiments involving orchidectomy with systemic testosterone replacement, and testicular efferent duct ligation, have indicated that structural and functional integrity of the initial segment cannot be maintained by circulating androgen alone, leaving the role of androgen in this epididymal zone unclear. We addressed this question in a mouse model with intact testicular output and selective Ar inactivation in the proximal epididymis by creating double-transgenic males carrying a conditional ArloxP allele and expressing Cre recombinase under the promoter of Rnase10, a gene specifically expressed in proximal epididymis. At 20–25 d of life, on the onset of Rnase10 expression, Ar became selectively inactivated in the principal cells of proximal epididymis, resulting in epithelial hypoplasia and hypotrophy. Upon the subsequent onset of spermiation, epididymal obstruction ensued, with the consequent development of spermatic granulomata, back pressure-induced atrophy of the seminiferous epithelium, orchitis, and fibrosis of the testicular parenchyma. Consistent with these findings, the mice were infertile. When the effect of Ar knockout on gene expression in the proximal epididymis was compared with that of efferent duct ligation and orchidectomy, we identified genes specifically regulated by androgen, testicular efferent fluid, and both. Our findings demonstrate that the development and function of the epididymal initial segment is critically dependent on direct androgen regulation. The phenotype of the produced knockout mouse provides a novel model for obstructive azoospermia.

Download Full-text

Absence of orthogonal arrays in kidney, brain and muscle from transgenic knockout mice lacking water channel aquaporin-4

Journal of Cell Science ◽

10.1242/jcs.110.22.2855 ◽

1997 ◽

Vol 110 (22) ◽

pp. 2855-2860 ◽

Cited By ~ 1

Author(s):

J.M. Verbavatz ◽

T. Ma ◽

R. Gobin ◽

A.S. Verkman

Keyword(s):

Cho Cells ◽

Collecting Duct ◽

Water Channel ◽

Freeze Fracture ◽

Orthogonal Arrays ◽

Knock Out ◽

Orthogonal Arrays Of Particles ◽

Freeze Fracture Electron Microscopy ◽

Knock Out Mice ◽

And Function

Freeze-fracture electron microscopy (FFEM) of kidney collecting duct, muscle, astrocytes in brain, and other mammalian tissues has revealed regular square arrays of intramembrane particles called orthogonal arrays of particles (OAPs). Their possible role in membrane structure and transport have been proposed, and their absence or decrease has been noted in a variety of hereditary and acquired diseases. A transgenic mouse lacking water channel AQP4 was used to show that AQP4 is the OAP protein. FFEM was done on kidney, skeletal muscle, and brain from AQP4 wild-type [+/+], heterozygous [+/−] and knock-out [-/-] mice. The [-/-] mice did not express detectable AQP4 protein, but were grossly indistinguishable from [+/+] mice. FFEM was done on blinded samples of kidney, brain and muscle from 9 mice. In all 6 kidney samples from [+/+] and [+/−] mice, OAPs similar to those in AQP4-transfected CHO cells were found in basolateral membranes of collecting duct principal cells. In all muscle and brain samples from [+/+] and [+/−] mice, OAPs of identical ultrastructure to those in kidney were seen, but in smaller patch sizes. OAPs were not seen in any sample from [-/-] mice. Label-fracture analysis using a peptide-derived AQP4 polyclonal antibody showed immunogold labeling of OAPs in AQP4-expressing CHO cells. These studies provide direct evidence that AQP4 is required for formation of OAPs and is a component of OAPs, thus establishing the identity and function of OAPs.

Download Full-text