SHIP and Immunoregulatory Cell Function

描述（由申请人提供）：我们先前证明了SHIP表达对于同种异体骨髓移植物的排斥是必需的（1），并且GvHD限制了此类移植物的效用。（1，2）我们最近发现，在异基因BMT之前诱导SHIP缺陷一周足以保护受体免受急性GvHD。(3)宿主抗原呈递细胞（APC）负责触发介导GVHD的同种异体T细胞应答（4）。(5)SHIP-/-小鼠外周淋巴器官中髓样抑制细胞（MySC）的显著扩增可拮抗APC引发的同种异体T细胞应答（2，3）。 我们最近已经表明，纯化的SHIP-/- MySC比WT MySC具有更大的抑制能力。(3)此外，我们已经表明，Treg细胞的数量和功能在生殖系SHIP缺陷型小鼠和诱导SHIP缺陷型小鼠中增加。因此，我们假设，在SHIP缺陷的移植受者中，MySC和/或Treg细胞功能的增加可以保护他们免受GvHD，并且还可以减少实体器官同种异体移植物排斥反应。我们最近建立了骨髓细胞和T细胞的谱系特异性SHIP缺失模型。我们现在将确定骨髓或T细胞限制性消融移植受者中SHIP表达是否足以消除急性GvHD（目的1）。最近建立了一个诱导型flox/flox SHIP缺失模型（MxCreSHIP），并证明这是一个有效的系统，我们可以在清髓性移植中保护成年受者免受GvHD，我们现在将确定诱导SHIP缺陷是否也可以保护其他同种异体BMT程序免受GvHD（目的2）。在目标3中，我们将使用MX-CreSHIP模型和靶向SHIP的RNAi来确定诱导的SHIP缺陷是否可以提高同种异体器官移植的成功率。我们还开发了RNAi方法来可逆地抑制SHIP在体内的表达。靶向SHIP表达的RNAi也将在Aim 2中测试其保护受体免受GvHD的能力，并在Aim 3中测试其是否可以促进实体器官同种异体移植物的植入。具体目的是：目的1：定义保护宿主免受GvHD所需的SHIP缺陷细胞谱系。目的2：确定SHIP缺陷可用于增强异基因骨髓移植的方式。目的3：确定SHIP缺陷是否可以促进同种异体器官移植。我们相信这些研究将证明，关闭一个特定的基因可以防止移植的骨髓和器官与受体不匹配的排斥反应。此外，这些研究将确定接受这些不匹配的移植所需的免疫细胞类型。

DESCRIPTION (provided by applicant): We previously demonstrated that SHIP expression is necessary for rejection of allogeneic BM grafts(1) and the GvHD that limits the utility of such transplants.(1,2) We have recently shown that induction of SHIP-deficiency for a one week period prior to allogeneic BMT is sufficient to protect a recipient from acute GvHD.(3) Host antigen presenting cells (APC) are responsible for triggering allogeneic T cell responses(4) that mediate GVHD.(5) A profound expansion of Myeloid Suppressor Cells (MySC) in the peripheral lymphoid organs of SHIP-/- mice antagonizes APC priming of allgeneic T cell responses (2,3). We have recently shown that purified SHIP-/- MySC have greater suppressive capacity than WT MySC.(3) In addition, we have shown that Treg cell numbers and function are increased in germline SHIP-deficient mice and mice with induced SHIP- deficiency. We hypothesize then that increased MySC and/or Treg cell function in SHIP-deficient transplant recipients protects them from GvHD and may also reduce solid organ allograft rejection. We have recently established lineage-specific SHIP deletion models for both myeloid cells and T cells. We will now determine whether myeloid- or T cell-restricted ablation of SHIP expression in transplant recipients is sufficient to abrogate acute GvHD (Aim 1). Having recently established an inducible flox/flox SHIP deletion model (MxCreSHIP ) and demonstrated that this is an effective system in which we can protect adult recipients from GvHD in a myeloablative transplant, we will now determine whether induced SHIP-deficiency is also protective from GvHD with other allogeneic BMT procedures (Aim 2). In Aim 3, we will use the MX-CreSHIP model and RNAi targeting of SHIP to determine whether induced SHIP deficiency can enhance the success of allogeneic organ transplantation. We have also developed RNAi approaches to reversibly inhibit SHIP expression in vivo. RNAi targeting of SHIP expression will also be tested in Aim 2 for its ability to protect recipients from GvHD and in Aim 3 to determine if it can facilitate engraftment of solid organ allografts. The Specific Aims are: Aim 1: Define the SHIP-deficient cell lineages required for host protection from GvHD. Aim 2: Define the manner in which SHIP-deficiency can be used to enhance allogeneic BM transplantation. Aim 3: Determine whether SHIP-deficiency can facilitate the transplantation of allogeneic organ grafts. PUBLIC HEALTH RELEVANCE We believe these studies will demonstrate that turning off one specific gene can prevent the rejection of transplanted bone marrow and organs that are not matched to the recipient. In addition, these studies will identify the types of immune cell types required for acceptance of these unmatched transplants.