Clarification of the protective mechanisms of pregnancy to the phenotype of saposin A deficient mice, mouse model for a late-onset, chronic form of globoid cell leukodystrophy

我们通过在鞘脂激活蛋白基因（prosaposin）的皂苷a区域引入一个突变（C106F），建立了一种新的小鼠模型，用于治疗迟发性慢性球状细胞白质营养不良（GLD， Krabbe病）。最有趣的是，我们发现妊娠皂苷A缺乏（皂苷A^<1/1>）小鼠的临床和病理有显著改善。我们还发现，高水平的雌激素（17β-雌二醇）补充可以在sapa ^<-/->小鼠中大量复制妊娠现象。基于这些证据，我们推测，在sap-A^<-/->小鼠脱髓鞘脑损伤中，怀孕期间较高的雌性激素（如雌激素）可以抑制小胶质细胞或巨噬细胞的激活，并阻止它们产生有害分子。为了验证ibis的假设，我们分析了性别、妊娠或雌性激素补充对sap-A^<-/->小鼠大脑中可变细胞因子和细胞因子受体mRNA表达的可能影响。然后我们发现sap-A^</->小鼠脑内的趋化因子和细胞因子显著上调，特别是在Rantes、MIP-1β、MIP-1α、MIP-2、MCP-1和TNF-α上。MIP-1(3)、MIP-1α、MIP-2和MCP-1的上调在雌性或妊娠sap-A^<-/->小鼠脑中均被抑制。对于趋化因子/细胞因子受体，我们发现在sap-A^<-/->小鼠的辫中TNF-α受体TNFR2和TNFR1的表达较高。我们还发现怀孕雌性sap-A^<-/->小鼠TNFR2表达降低。提示妊娠对sapa ^<-/->小鼠脱髓鞘性脑损伤具有抗炎作用。为了进一步评估妊娠和17β-雌二醇治疗的影响，我们将利用DNA微阵列来阐明sap-A^<-/->小鼠大脑中基因表达的全局模式。该方法将提取免疫相关基因以外的未知基因，并发挥明确妊娠对脱髓鞘病的保护机制的作用

We have generated a new mouse model for a late-onset, chronic form of globoid cell leukodysirophy (GLD, Krabbe disease), by introducing a mutation (C106F) into the saposin A domain of the sphingolipid activator protein gene (prosaposin). Most interestingly, we found significant clinical and pathological improvements in the pregnant saposin A deficient (sap A^<1/1>) mice. We also found that high level of estrogen (17β-estrdiol) supplementation could substantially duplicate the phenomena of pregnancy in sap-A^<-/-> mice. Based on these evidences, we hypothesize that higher female sex hormones such as estrogen during pregnancy can suppress the activation of microglia or macrophages and prevent them producing detrimental molecules in the demyelinating brain lesions of sap-A^<-/->mice. To evaluate ibis hypothesis, we analyzed the possible effect of gender, pregnancy or female sex hor lone supplementation to the mRNA expression of variable cytokines and cytokine receptors in the brain of sap-A^<-/-> mice. Then we found dramatic upregulation of chemokines and cytokines in the brain of sap-A^</-> mice, especially on Rantes, MIP-1β, MIP-1α, MIP-2, MCP-1 aid TNF-α. These upregulations of Rantes, MIP-1(3, MIP-1α, MIP-2 and MCP-1 were suppressed in female or pregnant sap-A^<-/-> mice brain. For chemokine/ cytokine receptors, we found higher expression of TNF-α receptors, both TNFR2 and TNFR1, in the braid of sap-A^<-/-> mice. We also found a reduced expression of TNFR2 in the pregnant female sap-A^<-/-> mice. These results suggest the anti-inflammatory effect of pregnancy to the demyelinating brain lesions of sap-A^<-/-> mice. To further evaluate the effect of pregnancy and 17β-estradiol treatment, we are going to utilize DNA microarrays to elucidate global patterns of gene expression in the brain of sap-A^<-/-> mice. This approach would pickup the unknown gene other than the immune related genes and play define the protective mechanism of pregnancy in the demyelinating disease