PARENT SESSION
BIOLOGY OF THE MALE REPRODUCTIVE TRACT
Harborside C
7:30 AM-10:00 AM

(570) THE PLIGHT OF MACROPHAGES AND HALO CELLS IN THE TESTIS AND EPIDIDYMIS OF CATHEPSIN A-DEFICIENT MICE.

Korah, Nadine¹, d'Azzo, Alessandra², El-Alfy, Mohamed³, Berger, Louise³, Hermo, Louis¹, ¹ Department of Anatomy and Cell Biology, Montreal, Canada² St. Jude Children's Research Hospital, Memphis, Tennessee³ Oncology and Molecular Endocrinology Research Center, Quebec City, Canada

ABSTRACT- Cathepsin A (PPCA) is a lysosomal carboxypeptidase that functions as a protective protein for -neuraminidase and -galactosidase in a multienzyme complex. PPCA-/- mice demonstrate major structural changes to Leydig cells of the testis, and epithelial cells of the epididymis. In the present study, these tissues and the efferent ducts (EDs), obtained from both PPCA-/- and +/+ mice of 2 to 10 months of age, were fixed for routine electron microscope (EM) analysis and for light microscope (LM) immunocytochemistry. In the testis of -/- mice, there was a dramatic increase in the number of macrophages in the interstitial space (IS) with age, identified as such with a cell surface monoclonal antibody F4/80. Unlike those of +/+ mice, these macrophages were large and engorged with pale multivesicular bodies (MVBs). In the EDs and epididymis, similar cells were noted in large numbers in the IS. Such cells were not evident in +/+ mice. In addition, while small spherical halo (immune) cells were evident in the epithelium of the EDs and epididymis of +/+ mice, no such cells were observed in -/- mice. In contrast, some cells residing at the base of the epithelium of -/- mice were abnormal in appearance showing an enormous size and cytoplasm filled with pale MVBs. Since these cells did not contact the basement membrane or lumen, it is suggested that they represent abnormal halo cells. To assess if the increase in number of macrophages is due to proliferation, an anti-cdc47 antibody was employed which detects cycling cells. In the testis, a reaction was noted over spermatogonia, while no cells of the IS or epithelium of the EDs and epididymis were reactive. In -/- mice, normal looking monocytes were at times observed in the IS, suggesting their recruitment from the blood and eventual differentiation into macrophages. The abnormal accumulation of MVBs in the cytoplasm of macrophages and halo cells suggests their active role in the endocytosis of substances from their surrounding environment and their inability to degrade these substances as a result of PPCA deficiency. The dramatic increase in the number of macrophages of -/- mice suggests that monocytes are being recruited from the blood in response to the difficulties encountered by the macrophages residing in the IS. (Supported by CIHR and NIH-DK52025.)

KEY WORDS: Cathepsin A (PPCA) knockout mice, macrophages, halo cells, male reproductive tract