Identification of Novel Genetic Risk Factors for Focal Segmental Glomerulosclerosis in Children: Results From the Chronic Kidney Disease in Children (CKiD) Cohort

RATIONALE & OBJECTIVE

Focal segmental glomerulosclerosis (FSGS) is a major cause of pediatric nephrotic syndrome, and African Americans exhibit an increased risk for developing FSGS compared with other populations. Predisposing genetic factors have previously been described in adults. Here we performed genomic screening of primary FSGS in a pediatric African American population.

STUDY DESIGN

Prospective cohort with case-control genetic association study design.

SETTING & PARTICIPANTS

140 African American children with chronic kidney disease from the Chronic Kidney Disease in Children (CKiD) cohort, including 32 cases with FSGS.

PREDICTORS

Over 680,000 common single-nucleotide polymorphisms (SNPs) were tested for association. We also ran a pathway enrichment analysis and a human leucocyte antigen (HLA)-focused association study.

OUTCOME

Primary biopsy-proven pediatric FSGS.

ANALYTICAL APPROACH

Multivariate logistic regression models.

RESULTS

The genome-wide association study revealed 169 SNPs from 14 independent loci significantly associated with FSGS (false discovery rate [FDR]<5%). We observed notable signals for genetic variants within the APOL1 (P=8.6×10^-7; OR, 25.8 [95% CI, 7.1-94.0]), ALMS1 (P=1.3×10^-7; 13.0% in FSGS cases vs 0% in controls), and FGFR4 (P=4.3×10^-6; OR, 24.8 [95% CI, 6.3-97.7]) genes, all of which had previously been associated with adult FSGS, kidney function, or chronic kidney disease. We also highlighted novel, functionally relevant genes, including GRB2 (which encodes a slit diaphragm protein promoting podocyte structure through actin polymerization) and ITGB1 (which is linked to renal injuries). Our results suggest a major role for immune responses and antigen presentation in pediatric FSGS through (1) associations with SNPs in PTPRJ (or CD148, P=3.5×10^-7), which plays a role in T-cell receptor signaling, (2) HLA-DRB1∗11:01 association (P=6.1×10^-3; OR, 4.5 [95% CI, 1.5-13.0]), and (3) signaling pathway enrichment (P=1.3×10^-6).

LIMITATIONS

Sample size and no independent replication cohort with genomic data readily available.

CONCLUSIONS

Our genetic study has identified functionally relevant risk factors and the importance of immune regulation for pediatric primary FSGS, which contributes to a better description of its molecular pathophysiological mechanisms.

CCDC7 Activates Interleukin-6 and Vascular Endothelial Growth Factor to Promote Proliferation via the JAK-STAT3 Pathway in Cervical Cancer Cells

Objective

Tumor growth is one of the most lethal attributes of human malignancy. The expression of CCDC7, a novel gene which has multiple functions, has been shown to be associated with tumor growth and poor prognosis in patients with cancer. However, the specific functions of CCDC7 remain unclear. Here, we investigated the molecular mechanisms underlying the effects of CCDC7 on proliferation in cervical cancer.

Materials and Methods

The MTT and EdU assays were performed to evaluate the function of CCDC7. The immunohistochemical, quantitative real-time PCR (qRT-PCR), ELISA and Western blot assay were used to detect the gene and protein expression in tissues and cells. A xenograft test was conducted to detect the impact of CCDC7 on tumor development in vivo .

Results

In immunohistochemical analysis of 193 cases, normal cervical tissue and cervical cancer tissue show that CCDC7 expression is closely correlated with the development of cervical cancer and was positively correlated with the clinical stage and histological grade. Overexpression or knockdown of CCDC7 affected cell proliferation in cervical cancer cells in vitro. In a nude mouse xenograft model in vivo, knockdown of CCDC7 inhibited cell proliferation and tumor growth. Furthermore, CCDC7 overexpression upregulated interleukin (IL)-6 and vascular endothelial growth factor (VEGF) at mRNA and protein levels, and treatment with recombinant IL-6 or VEGF proteins also increased CCDC7 expression. In a case set of 80 patients with cervical cancer, we found that CCDC7, IL-6, and VEGF affected patient prognosis. Finally, inhibition of various signaling pathways using specific inhibitors indicated that CCDC7 blocked the decrease in cell proliferation observed following suppression of the JAK-STAT3 pathway, suggesting that CCDC7 functioned via this critical signaling network.

Conclusion

Those findings indicated that CCDC7 may be a novel target for the treatment of cervical cancer and may have applications as a predictive marker for tumor growth in cervical carcinoma.