title: Distribution of prosaposin in rat lymphatic tissues.
abstract: Prosaposin (PSAP) is as a trophic factor and an activator protein for sphingolipid hydrolase in lysosomes. We generated a specific antibody to PSAP and examined the spatiotemporal distribution of PSAP-immunoreactive (PSAP-IR) cells in the lymphatic tissues of Wistar rats. Immunoblots of tissue homogenates separated electrophoretically showed a single band for PSAP in brain but two bands in spleen. PSAP-IR cells were distributed in both the red and white pulp of the spleen, in both the cortex and medulla of the thymus and in mesenteric lymph nodes. Many PSAP-IR cells were found in the dome portion of Peyer's patches and the number of PSAP-IR cells increased with the age of the rat. To identify the PSAP-IR cells, double- and triple-immunostainings were performed with antibodies against PSAP, CD68 and CD1d. The large number of double- and triple-positive cells suggested that antigen-presenting cells contained much PSAP in these lymphatic tissues. Intense expression of PSAP mRNA, examined by in situ hybridisation, was observed in the red pulp and corona of the spleen. In rats, the PSAP gene generates two alternative splicing forms of mRNA: Pro+9 containing a 9-base insertion and Pro+0 without the insertion. We examined the expression patterns of the alternative splicing forms of PSAP mRNA in the spleen. The presence of both types of mRNA (Pro+9 and Pro+0) indicated that the spleen contains various types of prosaposin-producing and/or secreting cells. These findings suggest diverse functions for PSAP in the immune system.
authors: Department of Anatomy and Embryology, Ehime University Graduate School of Medicine, Toon, Ehime, 791-0212, Japan. tshimo@m.ehime-u.ac.jp
authors: Tetsuya
authors: T
authors: Shimokawa
authors: Hiroaki
authors: H
authors: Nabeka
authors: Kimiko
authors: K
authors: Yamamiya
authors: Hiroyuki
authors: H
authors: Wakisaka
authors: Takashi
authors: T
authors: Takeuchi
authors: Naoto
authors: N
authors: Kobayashi
authors: Seiji
authors: S
authors: Matsuda
mesh_terms: D000818:Animals; D015153:Blotting, Western; D045424:Complex Mixtures; D005786:Gene Expression Regulation; D008221:Lymphoid Tissue / Q000166:cytology / Q000378:metabolism*; D008297:Male; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D049231:Saposins / Q000235:genetics / Q000378:metabolism*; D013154:Spleen / Q000166:cytology / Q000378:metabolism; D014020:Tissue Extracts
chemical_list: D045424:Complex Mixtures; C483347:Psap protein, rat; D012333:RNA, Messenger; D049231:Saposins; D014020:Tissue Extracts