Mehanizmi nastanka koštanog fenotipa u generaliziranom limfoproliferativnom poremećaju u miša [ Mechanism of development of bone phenotype in murine generalised lymphoproliferative disorder ]

Lukić, Ivan Krešimir (2005) Mehanizmi nastanka koštanog fenotipa u generaliziranom limfoproliferativnom poremećaju u miša [ Mechanism of development of bone phenotype in murine generalised lymphoproliferative disorder ]. PhD thesis, Sveučilište u Zagrebu.

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Abstract

Mice with mutation in the Fas-ligand gene develop generalised lymphoproliferative disorder (gld mice), characterised by accumulation of double negative (DN) T cells (CD4–CD8–), as well as higher bone mineral density and more trabecular bone. To evaluate the role of immune system in the development of bone phenotype of gld mice, we parabiotically joined the wild-type (C57BL/6, B6) with gld mice. The mice were sacrificed weekly for four weeks. Additionally, the mice were separated after four weeks and sacrificed two weeks after separation. Lymphoproliferative disorder was suppressed in gld mice during the first week and the suppression was evident even after the animals were separated. The proportion of DN T cells in the lymphoid tissues of B6 increased during parabiosis, suggesting that the immune phenotype of B6 mice became similar to that of gld mice. At the same time, the bone phenotype of B6 animals shifted towards the gld bone phenotype. The number of osteoclast precursors in the cell culture of B6 bone marrow decreased at one and four weeks, while the number of osteoblast precursors increased at four weeks after parabiosis. The alterations of B6 bone marrow during parabiosis were paralleled by increased expression of cytokine osteoprotegerin in the bone, both at the gene and the protein levels, suggesting that osteoprotegerin was the link between the bone and immune phenotype. Simultaneous transfer of both immune and bone phenotype from gld to B6 mice point to the immune component of gld bone phenotype. On the other hand, lack of changes in the bone marrow of gld mice during parabiosis indicated that Fas-ligand has a direct role in the formation of bone phenotype of gld mice.

Abstract in Croatian

Miševi s mutacijom gena za ligand Fas (soj gld) boluju od općeg limfoproliferativnog poremećaja, obilježenog nakupljanjem dvostruko negativnih (DN; CD4–CD8–) limfocita T, te imaju veću koštanu gustoću i više trabekularne kosti. Kako bismo procijenili ulogu imunosnog sustava u nastanku koštanog fenotipa miševa gld, parabiotski smo ih spojili s miševima divljeg tipa (C57BL/6, B6) te kroz mjesec dana žrtvovali svaki tjedan, odnosno nakon mjesec dana rastavili te žrtvovali nakon dodatna dva tjedna. Limfoproliferativni poremećaj u miševa soja gld ublažen je već tjedan dana nakon početka parabioze te je poboljšanje bilo vidljivo i nakon rastavljanja životinja. U miševa soja B6 je tijekom parabioze došlo do porasta broja DN limfocita T u tkivima, što znači da im se imunofenotip približio onome u miševa soja gld. Usporedno s imunofenotipom je u miševa soja B6 promijenjen i koštani fenotip i to u smjeru nalaza tipičnih za soj gld. Jedan i četiri tjedna nakon parabiotskog spajanja je u staničnoj kulturi koštane srži miševa soja B6 došlo do smanjenja broja osteoklastnih prethodnika, a k tome se četiri tjedna nakon operacije povećao broj osteoblastnih prethodnika. Promjene u koštanoj srži miševa soja B6, tijekom parabioze, bile su praćene i povećanjem izražaja citokina osteoprotegerina u kosti, na genskoj i bjelančevinskoj razini, što ukazuje da je osteoprotegerin bio poveznica imunosnog i koštanog fenotipa. Istovremeni prijenos imunosnog i koštanog fenotipa s miša soja gld u miša soja B6 upućuje na postojanje imunosne komponente koštanog fenotipa miševa soja gld. S druge strane, izostanak promjena u koštanoj srži miševa gld tijekom parabioze pokazuje da ligand Fas ima neposrednu ulogu u oblikovanju koštanog fenotipa miševa soja gld.

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