Barua M, etal., J Am Soc Nephrol. 2014 Sep;25(9):1942-53. doi: 10.1681/ASN.2013070686. Epub 2014 Mar 27.
FSGS is characterized by the presence of partial sclerosis of some but not all glomeruli. Studies of familial FSGS have been instrumental in identifying podocytes as critical elements in maintaining glomerular function, but underlying mutations have not been identified for all forms of this genetica
lly heterogeneous condition. Here, exome sequencing in members of an index family with dominant FSGS revealed a nonconservative, disease-segregating variant in the PAX2 transcription factor gene. Sequencing in probands of a familial FSGS cohort revealed seven rare and private heterozygous single nucleotide substitutions (4% of individuals). Further sequencing revealed seven private missense variants (8%) in a cohort of individuals with congenital abnormalities of the kidney and urinary tract. As predicted by in silico structural modeling analyses, in vitro functional studies documented that several of the FSGS-associated PAX2 mutations perturb protein function by affecting proper binding to DNA and transactivation activity or by altering the interaction of PAX2 with repressor proteins, resulting in enhanced repressor activity. Thus, mutations in PAX2 may contribute to adult-onset FSGS in the absence of overt extrarenal manifestations. These results expand the phenotypic spectrum associated with PAX2 mutations, which have been shown to lead to congenital abnormalities of the kidney and urinary tract as part of papillorenal syndrome. Moreover, these results indicate PAX2 mutations can cause disease through haploinsufficiency and dominant negative effects, which could have implications for tailoring individualized drug therapy in the future.
Li L, etal., Zhongguo Dang Dai Er Ke Za Zhi. 2016 Jun;18(6):551-7.
OBJECTIVE: To investigate the influence of silencing PAX2 gene in vivo on epithelial-mesenchymal transition (EMT) of renal tubular cells in rats with renal interstitial fibrosis. METHODS: A total of 64 Wistar rats were anaesthetized, and uni
lateral ureteral obstruction (UUO) was performed to establish a rat model of renal interstitial fibrosis. The 64 rats were randomly divided into negative control and PAX2 gene silencing groups (n=32 each). The rats in the control group were transfected with 200 µL NC-siRNA-in vivo jetPEI(TM) solution. Those in the PAX2 gene silencing group were transfected with 200 µL PAX2-siRNA-in vivo jetPEI(TM) solution. Each group was further divided into 4 subgroups based on the post-transfection time (3, 5, 7 and 14 days after transfection), with 8 rats in each subgroup. Renal tissue samples were harvested in each group. Real-time PCR and Western blot were used to measure the mRNA and protein expression of PAX2 in the renal cortex, as well as the mRNA and protein expression of E-cadherin and a-SMA. RESULTS: Compared with the control group, the PAX2 gene silencing group showed significantly lower mRNA and protein expression of PAX2 (P<0.05). In the two groups, the mRNA and protein expression levels of E-cadherin were gradually reduced over the time of obstruction, while those of a-SMA gradually increased. At 14 days after transfection, the PAX2 gene silencing group had significantly higher mRNA and protein expression of E-cadherin but lower mRNA and protein expression of a-SMA compared with the control group (P<0.05). CONCLUSIONS: PAX2 gene silencing can significantly inhibit the process of EMT of renal tubular cells in rats with advanced fibrosis, suggesting that PAX2 gene silencing may have a therapeutic effect on renal interstitial fibrosis.
Al-Hujaily EM, etal., Cancer Prev Res (Phila). 2015 Dec;8(12):1163-73. doi: 10.1158/1940-6207.CAPR-15-0121-T. Epub 2015 Sep 15.
PAX2 is an essential transcription factor for development. Aberrant PAX2 expression in adult tissues is associated with carcinogenesis and experimental evidence shows that PAX2 generally
exhibits oncogenic properties. Although PAX2 is not expressed in normal ovaries, it is highly expressed in low malignant potential and low-grade epithelial ovarian tumors, suggesting that PAX2 induction in ovarian surface epithelium (OSE) may contribute to transformation. Herein, we provide evidence that expression of PAX2 in normal murine OSE cells (mOSE) enhances their proliferation and survival and, with loss of p53, induces tumorigenicity. PAX2 expression in murine ovarian cancer cells enhanced or inhibited tumorigenicity, depending on the model system. In RM cells (mOSE transformed by K-RAS and c-MYC), PAX2 expression inhibited p53 and induced pERK1/2 and COX2, resulting in enhanced angiogenesis and decreased apoptosis of tumors arising from these cells. However, in a murine model of high-grade serous ovarian cancer (STOSE), PAX2 expression improved animal survival by reducing proliferation and metastasis, which correlated with increased Htra1 and decreased COX2. Thus, PAX2 may not be a classical oncogene or tumor suppressor but instead can act in either role by differential regulation of COX2 and/or HTRA1.
Madariaga L, etal., Clin J Am Soc Nephrol. 2013 Jul;8(7):1179-87. doi: 10.2215/CJN.10221012. Epub 2013 Mar 28.
BACKGROUND AND OBJECTIVES: Congenital anomalies of the kidney and urinary tract (CAKUT) are a frequent cause of renal failure in children, and their detection in utero is now common with fetal screening ultrasonography. The clinical course of CAKUT detected before birth is very heterogeneous and de
pends on the level of nephron reduction. The most severe forms cause life-threatening renal failure, leading to perinatal death or the need for very early renal replacement therapy. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: This study reports the screening of two genes (HNF1B and PAX2) involved in monogenic syndromic CAKUT in a cohort of 103 fetuses from 91 families with very severe CAKUT that appeared isolated by fetal ultrasound examination and led to termination of pregnancy. RESULTS: This study identified a disease-causing mutation in HNF1B in 12 cases from 11 families and a mutation in PAX2 in 4 unrelated cases. Various renal phenotypes were observed, but no case of bilateral agenesis was associated with HNF1B or PAX2 mutations. Autopsy identified extrarenal abnormalities not detected by ultrasonography in eight cases but confirmed the absence of extrarenal defects in eight other cases. A positive family history of renal disease was not significantly more frequent in cases with an identified mutation. Moreover, in cases with an inherited mutation, there was a great phenotypic variability regarding the severity of the renal disease within a single family. CONCLUSIONS: Our results suggest that mutations in genes involved in syndromic CAKUT with Mendelian inheritance are not rare in fetal cases with severe CAKUT appearing isolated at prenatal ultrasound, a finding of clinical importance because of genetic counseling.
Solitary fibrous tumor (SFT), a mesenchymal neoplasm with widespread anatomic distribution, can be diagnostically challenging in limited samples. We recently encountered an aspirate of a pancreatic mass, incorrectly interpreted as metastatic renal cell carcinoma based on strong PAX8 expression by im
munohistochemistry (IHC). After resection, morphologic features with additional IHC (CD34 positivity) correctly identified this lesion as a SFT. PAX8 and PAX2 are commonly used as renal tumor markers; however, no series has investigated PAX8 or PAX2 expression in SFT. IHC for PAX8 and PAX2 was performed on 41 SFTs (biopsy and resections) from varying sites. Eight were histologically malignant and eight were recurrences of previous resections. PAX8 staining was observed at least focally in 26.8% (11 of 41) SFT cases; additionally, PAX2 was positive in 12.2% (5 of 41 cases) of SFTs. For PAX8 and PAX2 positive cases 45.6% and 40%, respectively, showed diffuse expression. No correlation was found between PAX8/PAX2 positivity and age, tumor size, site, malignancy, or recurrence. In conclusion, a substantial minority of SFTs express PAX8 and PAX2 via IHC. This presents a diagnostic pitfall when evaluating possible metastases from the kidney, particularly when primary tumors show sarcomatoid or spindle cell morphologies.
Brophy PD, etal., J Biol Chem 2003 Dec 26;278(52):52401-5. Epub 2003 Oct 15.
Despite their essential role in vertebrate development, the function of Pax proteins in gene regulation is not well understood. To identify potential genes regulated by the Pax2 protein, we screened embryonic kidney cells transformed with Pax2
t:700;'>Pax2-expressing retroviruses for genes activated in response to Pax2 expression. In this system, the gene encoding the secreted frizzled related protein, Sfrp2, was strongly activated in all Pax2b-expressing cells. This activation of Sfrp2 expression correlated with changes in chromatin structure at the Sfrp2 locus, particularly in and around regions of Pax2 binding. Although the amount of Pax2-dependent transactivation was low in transient assays, the data suggests that local alterations of chromatin structure by Pax proteins can greatly enhance expression when presented in the right cellular context.
BACKGROUND: Renal coloboma syndrome (RCS) is characterized by renal anomalies and optic nerve colobomas. PAX2 mutations contribute to RCS. However, approximately half of the patients with RCS have no mutation in PAX2 gene. M
ETHODS: To investigate the incidence and effects of mutations of PAX2 and 25 candidate genes, patient genes were screened using next-generation sequence analysis, and candidate mutations were confirmed using Sanger sequencing. The correlation between mutations and clinical manifestation was evaluated. RESULT: Thirty patients, including 26 patients (two families of five and two, 19 sporadic cases) with RCS, and 4 optic nerve coloboma only control cases were evaluated in the present study. Six PAX2 mutations in 21 probands [28%; two in family cohorts (n = 5 and n = 2) and in 4 out of 19 patients with sporadic disease] including four novel mutations were confirmed using Sanger sequencing. Moreover, four other sequence variants (CHD7, SALL4, KIF26B, and SIX4) were also confirmed, including a potentially pathogenic novel KIF26B mutation. Kidney function and proteinuria were more severe in patients with PAX2 mutations than in those without the mutation. Moreover, the coloboma score was significantly higher in patients with PAX2 gene mutations. Three out of five patients with PAX2 mutations had focal segmental glomerulosclerosis (FSGS) diagnosed from kidney biopsies. CONCLUSION: The results of this study identify several new mutations of PAX2, and sequence variants in four additional genes, including a novel potentially pathogenic mutation in KIF26B, which may play a role in the pathogenesis of RCS.
Eccles MR, etal., Am J Pathol. 1995 Jan;146(1):40-5.
Wilms' tumor (WT) is a childhood renal neoplasm with histological features resembling fetal kidney development. Two members of the paired box family of genes, PAX2 and PAX8, are expressed in WT and are potentially involved in its induction. A zinc finger gene, W
T1, which is involved in WT induction, encodes a DNA binding protein, and like PAX2 and PAX8 proteins is a transcription factor with an important role in kidney development. We have compared the expression patterns of PAX2, PAX8, and WT1 in fetal kidney and WTs by in situ hybridization. The PAX2, PAX8, and WT1 genes were transcribed in the condensed mesenchyme and early stages of epithelial differentiation in fetal kidney. WT1 gene transcription was observed in the glomeruli of fetal kidney until a later stage in development than PAX genes. In WTs all three genes were expressed in the condensed blastema, but WT1 expression was not detectable in the epithelial structures in two WTs. No evidence of attenuation of PAX gene expression was found in WT. These results suggest that in some WTs the expression of WT1 is attenuated in structures that continued to express PAX genes. It is unlikely that both PAX2 and PAX8 genes would be mutated in WT. However, failure of PAX gene expression to attenuate in WTs may result from mutations involved in the onset of the tumor.
Ren Y, etal., Int J Clin Exp Pathol. 2015 Nov 1;8(11):14709-16. eCollection 2015.
Lung cancer is the leading cause of cancer-related death in both men and women and consists of different histological types. Histopathological examination and accurate subtype diagnosis has become increasingly important in guiding patient management and, as such, is the most important currently avai
lable lung cancer "biomarker". In this study, we examined the expression of PAX2 and PAX5 by immunohistochemistry in 47 cases of lung cancer and 13 cases of pneumonia. The results demonstrated that PAX2 were detected in 82.8% (24/29) of NSCLC, 0% (0/18) of SCLC and 7.7% (1/13) of pneumonia, respectively; However, PAX5 were detected in 15/18 cases (83.3%) of SCLC, 6.8% (2/29) of NSCLC and 7.7% (1/13) of pneumonia. Further, the samples with lymphatic metastasis had remarkable higher positive PAX2 or PAX5 than that without metastases. Overall, our data indicated that PAX2 and PAX5 differentially expressed in NSCLC and SCLC. Thus, PAX2 and PAX5 are useful biomarker in the differential diagnosis of lung cancer.
Paired box (PAX) genes play a critical role in human development and disease. The PAX2 gene is expressed in primitive cells of the kidney, ureter, eye, ear and central nervous system. We have conducted a mutational analysis of PAX2
in a family with optic nerve colobomas, renal hypoplasia, mild proteinuria and vesicoureteral reflux. We report a single nucleotide deletion in exon five, causing a frame-shift of the PAX2 coding region in the octapeptide domain. The phenotype resulting from the PAX2 mutation in this family was very similar to abnormalities that have been reported in Krd mutant mice. These data suggest that PAX2 is required for normal kidney and eye development.
Gough SM, etal., BMC Genomics. 2003 Mar 3;4(1):9. Epub 2003 Mar 3.
BACKGROUND: Chromosome band 10q24 is a gene-rich domain and host to a number of cancer, developmental, and neurological genes. Recurring translocations, deletions and mutations involving this chromosome band have been observed in different human cancers and other disease conditions, but the precise
identification of breakpoint sites, and detailed characterization of the genetic basis and mechanisms which underlie many of these rearrangements has yet to be resolved. Towards this end it is vital to establish a definitive genetic map of this region, which to date has shown considerable volatility through time in published works of scientific journals, within different builds of the same international genomic database, and across the differently constructed databases. RESULTS: Using a combination of chromosome and interphase fluorescent in situ hybridization (FISH), BAC end-sequencing and genomic database analysis we present a physical map showing that the order and chromosomal orientation of selected genes within 10q24 is CEN-CYP2C9-PAX2-HOX11-NFKB2-TEL. Our analysis has resolved the orientation of an otherwise dynamically evolving assembly of larger contigs upstream of this region, and in so doing verifies the order and orientation of a further 9 cancer-related genes and GOT1. This study further shows that the previously reported human papillomavirus type 6a DNA integration site HPV6AI1 does not map to 10q24, but that it maps at the interface of chromosome bands 14q13.3-q21.1. CONCLUSIONS: This revised map will allow more precise localization of chromosome rearrangements involving chromosome band 10q24, and will serve as a useful baseline to better understand the molecular aetiology of chromosomal instability in this region. In particular, the relocation of HPV6AI1 is important to report because this HPV6a integration site, originally isolated from a tonsillar carcinoma, was shown to be rearranged in other HPV6a-related malignancies, including 2 of 25 genital condylomas, and 2 of 7 head and neck tumors tested. Our finding shifts the focus of this genomic interest from 10q24 to the chromosome 14 site.
