Role of GLIS2 in the Development of Cystic Kidney Disease

描述（由申请人提供）：肾营养不良（NPHP）是生命最初30年中慢性肾衰竭最常见的遗传原因之一，是一组常染色体 以进行性肾脏囊性变性和纤维化为特征的隐性疾病。GLIS 2/NPHP 7基因突变是人类和小鼠7型肾单位结核的原因。GLIS 2是一个转录因子，与果蝇（Drosophila Ci）的脊椎动物直系同源物GLI 1、GLI 2和GLI 3具有高度的序列同源性。与果蝇Ci一样，GLI蛋白是脊椎动物Hedgehog（Hh）信号传导的关键分子，该信号传导途径在进化中高度保守，并且在胚胎和出生后的生命期间的增殖、分化和修复的调节中起中心作用。我们最近测试并证实了Glis 2是出生后肾脏中Hh信号传导的阻遏物的假设，并证明该途径的故障导致肾囊肿和纤维化，增加炎症浸润和细胞凋亡，但导致这种肾脏表型的分子事件仍然无法解释。在我的实验室进行的初步研究意外地发现，损失Glis 2的结果在过度表达的Toll样受体2（Tlr 2）和其他成分的促炎TLR/NF-？B途径在肾上皮细胞和在Tlr 2依赖性激活这一途径。我们还发现，在肾脏上皮细胞中的几种miRNAs的表达是由Glis 2控制的，这表明microRNAs是小鼠肾脏中Glis 2/Hh信号传导的效应子。我们建议在体内测试TLR-2/NF-？通过产生Tlr 2-/-; Glis 2 mut/mut和Myd 88 flox/flox; Glis 2 mut/mut;KspCre双突变体和建立Tlr 2-/-; Glis 2 mut/mut骨髓嵌合体，观察B信号对Glis 2 mut/mut小鼠肾脏中炎性浸润和纤维化的影响。此外，我们还提出了在全基因组水平上通过染色质免疫沉淀-高度平行测序（ChIP-Seq）和高通量microRNA测序（miRNA-Seq）来系统地鉴定经典和非经典Glis 2靶基因。根据我们最近的结果，确定Glis 2敲除肾脏中失调的下游效应子变得更加重要，并且可能会在我们的囊性肾病和纤维化模型中改变的复杂调控网络中产生进一步的见解。

DESCRIPTION (provided by applicant): Nephronophthisis (NPHP), one of the most frequent genetic causes of chronic renal failure in the first three decades of life, is a group of autosomal recessive diseases characterized by progressive kidney cystic degeneration and fibrosis. Mutations in the gene GLIS2/NPHP7 are the cause of nephronophthisis type 7 both in humans and mice. GLIS2 is a transcription factor with high sequence homology to GLI1, GLI2 and GLI3, the vertebrate orthologs of Drosophila Ci (cubitus interruptus). Like Drosophila Ci, GLI proteins are key molecules in the vertebrate Hedgehog (Hh) signaling, a pathway highly conserved in the evolution and central in the regulation of proliferation, differentiation and repair during embryonc and postnatal life. We have recently tested and confirmed the hypothesis that Glis2 is a repressor of Hh signaling in the postnatal kidney and demonstrated that malfunctioning of this pathway results in kidney cysts and fibrosis, increased inflammatory infiltration and apoptosis, but the molecular events leading to this kidney phenotype are still unexplained. Preliminary studies performed in my laboratory have unexpectedly revealed that loss of Glis2 results in over expression of Toll like receptor 2 (Tlr2) and other components of the pro-inflammatory TLR/NF- ?B pathway in kidney epithelial cells and in the Tlr2-dependent activation of this pathway. We have also found that expression of several miRNAs in kidney epithelial cells is controlled by Glis2, suggesting that microRNAs are effectors of Glis2/Hh signaling in mouse kidneys. We propose to test in vivo the effect of the inhibition of TLR-2/NF-?B signaling on the inflammatory infiltration and fibrosis in Glis2mut/mut mice kidneys by generating Tlr2-/-;Glis2mut/mut and Myd88flox/flox;Glis2mut/mut;KspCre double mutants and establishing Tlr2-/-;Glis2mut/mut bone marrow chimeras. In addition, we propose to systematically identify at genome wide level the canonical and non-canonical Glis2 target genes by chromatin immunoprecipitation-highly parallel sequencing (ChIP-Seq) and high-throughput microRNA sequencing (miRNA-Seq). In light of our most recent results, identifying downstream effectors that are deregulated in Glis2 knockout kidneys has gained even more importance, and is likely to produce further insights in the complex regulatory network that is altered in our model of cystic kidney diseases and fibrosis.