Increased expression of the potential proapoptotic molecule DD2 and increased synthesis of leukotriene B4 during allograft rejection in a marine sponge

Abstract

Sponges (Porifera) are a classical model to study the events during tissue transplantation. Applying the`insertion technique' autografts from the marine sponge Geodia cydonium fuse within 5 days. In contrast, allografts are rejected and destroyed. Here we show that during allograft rejection the cells in the grafts undergo apoptosis; 5 days after transplantation 46% of the cells show signs of apoptosis. In a previous study it was shown that during this process a tumor necrosis factor-like molecule is induced in allo-and xenografts. Molecules grouped to the superfamily of tumor necrosis factor receptors and a series of associated adapter molecules contain the characteristic death domain. Therefore, we screened for a cDNA encoding such a domain. Here we report on the first invertebrate molecule from Geodia cydonium comprising a death domain. The potential proapoptotic molecule DD2, with a calculated M r of 24 970, possesses in contrast to all known mammalian death domaincontaining proteins two such domains with highest similarity to the death domain present in human Fas/APO-1. The expression of this gene is not detectable in control tissue but strongly upregulated in allografts; only very low expression is seen in autografts. Parallel with the increase of the expression of the potential proapoptotic molecule DD2 in allografts the level of LTB 4 drastically increases from 2.5 pg/mg of protein (controls) to 389 pg LTB 4 /mg during a period of 5 days after transplantation; the level of LTB 4 in autografts does not change. Very likely in response to inflammatory reactions the LTB 4 metabolizing enzyme LTB 4 12-hydroxy-dehydrogenase is expressed both in auto-and allografts. These results demonstrate that sponges are provided with apoptotic pathways, similar to those present in deuterostomes and apparently absent in protostomes, which are composed of molecules comprising a death domain. In addition, it is suggested that in sponges LTB 4 is one metabolite which is involved in the initiation of apoptosis. It is postulated that the potential proapoptotic effect of LTB 4 is prevented in autografts by the expression of the LTB 4 12-hydroxy-dehydrogenase. Cell Death and Differentiation (2000) 7, 461 ± 469.

Living with death: the evolution of the mitochondrial pathway of apoptosis in animals

“…70 GCBHP2 expression is upregulated in sponge cells exposed to low Apical and initiator caspase homologs, pro-and antiapoptotic Bcl-2 family members. Caspase-dependent cell death observed in allograft rejection [67][68][69][70][71][72] (but not high) levels of tributyltin or heat shock, and GCBHP2 appears to have an antiapoptotic role. Mammalian cells transfected with GCBHP2 were somewhat resistant to serum starvation and tributylin-induced apoptosis.…”

“…Although the autografts fuse within 5 days, approximately half of the cells in the allograft show positive TUNEL staining and characteristic DNA fragmentation during the same period. 67 Extracts made from allografts, but not autografts, cleave a caspase substrate, indicating caspase-like activity. 68 Apoptotic genes have been identified in several species of sponges, and two sponge caspases have been cloned (GEOCYCAS3l and GEOCYCAS3s).…”

Sponge Bcl-2 homologous protein (BHP2-GC) confers distinct stress resistance to human HEK-293 cells

“…Until recent discoveries 1,2 it was assumed that the physiological cell death is restricted to multicellular organisms, which have separate germ and somatic cells. 3 Originally it was suggested to divide the physiological cell death into two processes: (a)`programmed cell death', describing the developmentally regulated elimination of specific cells during embryogenesis, 4 and (b)`apoptotis', describing morphological changes of dying cells.…”

“…Subsequent studies elucidated that in sponges, with the two demosponges Geodia cydonium and Suberites domuncula as the most thoroughly investigated examples, polypeptide sequences exist which comprise high sequence similarities to members of the wider Bcl-2 family 1,2 as well as to pro-apoptotic molecules containing the death domain. 2 Members of the Bcl-2 family are defined by the conservation of two domains, termed Bcl-2 homology domain-1 and -2 (BH1 and BH2). 12,13 The Bcl-2 family comprises pro-survival molecules, e.g.…”

Cyclosporin A Suspends Transplantation Reactions in the Marine SpongeMicrociona prolifera

“…Biochemical and immunohistochemical methods were later used to study apoptotic cell death in sponge extracts where caspase 3 activity was found to be greatly increased in allografts when compared with isografts (26,27). Higher expression of other molecules potentially related to apoptosis has been detected in allografts of several sponge species (28,29).…”