Expression of fractalkine in the rat testis: molecular cloning of a novel alternative transcript of its gene that is differentially regulated by pro-inflammatory cytokines.
The testis is a very complex organ in which cellular communications and interactions are central to spermatogenesis and where inflammatory processes can lead to sterility. Fractalkine (CX3CL1) is a chemokine involved in cell-cell interactions and in leukocyte chemoattraction. It has been reported to be expressed in testis, but its cellular expression and function in this organ has not been described. In this study we report constitutive expression of fractalkine in the testis. Expression is higher in Leydig cells than Sertoli cells, spermatogonia, pachytene spermatocytes and elongated spermatids. In both, Sertoli cells stimulated by interleukin-1beta and tumour necrosis factor alpha, and in Leydig cells, two forms of fractalkine mRNA were observed: the previously described transcript of 3.7 kb and a novel transcript of 4.2 kb. The 4.2 kb transcript has a 5' elongation and is differentially regulated. To investigate fractalkine function in testis, we abolished Leydig cell expression of fractalkine by specific destruction of this cell type using ethylene dimethane sulphonate. The absence of fractalkine expression in Leydig cells did not seem to affect the fractalkine expression by other testicular cells. In addition, the destruction of testicular macrophages by Cl2MDP (chlodronate) did not seem to affect Leydig cell expression of fractalkine. We conclude that Leydig cell expression of fractalkine could be preferentially involved in inflammation in interstitial space whereas fractalkine expressed by germ cells may participate in the cellular interactions between germ cells and other seminiferous tubule cell types.
Habasque
Cécile
C
INSERM U. 435-GERM, Université de Rennes I, Campus de Beaulieu, 35042 Rennes cedex, Bretagne, France.
Satie
Anne-Pascale
AP
Aubry
Florence
F
Jégou
Bernard
B
Samson
Michel
M
D017398:Alternative Splicing; D000818:Animals; D000963:Antimetabolites / Q000378:metabolism; D001483:Base Sequence; D002478:Cells, Cultured; D054428:Chemokine CX3CL1; D020523:Chemokines, CX3C / Q000235:genetics* / Q000378:metabolism*; D004002:Clodronic Acid / Q000378:metabolism; D016207:Cytokines / Q000378:metabolism*; D005786:Gene Expression Regulation; D007985:Leydig Cells / Q000166:cytology / Q000378:metabolism*; D008264:Macrophages / Q000378:metabolism; D008297:Male; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D051381:Rats; D017207:Rats, Sprague-Dawley; D012708:Sertoli Cells / Q000166:cytology / Q000378:metabolism*
D000963:Antimetabolites; D054428:Chemokine CX3CL1; D020523:Chemokines, CX3C; C515540:Cx3cl1 protein, rat; D016207:Cytokines; D008565:Membrane Proteins; D004002:Clodronic Acid