Association between a single-nucleotide polymorphism in the GREM1 gene and non-syndromic orofacial cleft in the Chinese population

Association between IRF6, TP63, GREM1 Gene Polymorphisms and Non-Syndromic Orofacial Cleft Phenotypes in Vietnamese Population: A Case-Control and Family-Based Study

This study aims to identify potential variants in the TP63-IRF6 pathway and GREM1 for the etiology of non-syndromic orofacial cleft (NSOFC) among the Vietnamese population. By collecting 527 case-parent trios and 527 control samples, we conducted a stratified analysis based on different NSOFC phenotypes, using allelic, dominant, recessive and over-dominant models for case-control analyses, and family-based association tests for case-parent trios. Haplotype and linkage disequilibrium analyses were also conducted. IRF6 rs2235375 showed a significant association with an increased risk for non-syndromic cleft lip and palate (NSCLP) and cleft lip with or without cleft palate (NSCL/P) in the G allele, with pallele values of 0.0018 and 0.0003, respectively. Due to the recessive model (p = 0.0011) for the NSCL/P group, the reduced frequency of the GG genotype of rs2235375 was associated with a protective effect against NSCL/P. Additionally, offspring who inherited the G allele at rs2235375 had a 1.34-fold increased risk of NSCL/P compared to the C allele holders. IRF6 rs846810 and a G-G haplotype at rs2235375-rs846810 of IRF6 impacted NSCL/P, with p-values of 0.0015 and 0.0003, respectively. In conclusion, our study provided additional evidence for the association of IRF6 rs2235375 with NSCLP and NSCL/P. We also identified IRF6 rs846810 as a novel marker associated with NSCL/P, and haplotypes G-G and C-A at rs2235375-rs846810 of IRF6 associated with NSOFC.

Increased hypospadias risk by GREM1 rs3743104[G] in the southern Han Chinese population

Hypospadias is a common congenital genitourinary malformation characterized by ventral opening of the urethral meatus. As a member of the bone morphogenic protein antagonist family, GREM1 has been identified as associated with susceptibility to hypospadias in the European population. The present study was designed to elaborate on the mutual relationship between replicated single-nucleotide polymorphisms (SNPs) and hypospadias in Asia's largest case-control study in the Southern Han Chinese population involving 577 patients and 654 controls. Our results demonstrate that the GREM1 risk allele rs3743104[G] markedly increases the risk of mild/moderate and severe hypospadias (P<0.01, 0.28≤OR≤0.66). GTEx expression quantitative trait locus data revealed that the eQTL SNP rs3743104 has more associations of eQTL SNP rs3743104 and GREM1 targets in pituitary tissues. Additionally, Bioinformatics and Luciferase Assays show that miR-182 is identified as a suppressor for GREM1 expression, likely through regulation of its binding affinity to rs3743104 locus. In conclusion, the GREM1 risk allele rs3743104[G] increases hypospadias susceptibility in mild/moderate and severe cases among the southern Han population. rs3743104 regulates GREM1 expression by altering the binding affinity of miR-182 to their locus. Collectively, this study provides new evidence that GREM1 rs3743104 is associated with an increased risk of hypospadias. These findings provide a promising biomarker and merit further exploration.

Association of Genetic Polymorphisms of GREM1 Gene with Susceptibility to Non-Syndromic Cleft Lip with or without Cleft Palate in an Iranian Population

Background: Nonsyndromic cleft lip with or without cleft palate (NSCL/P) is common congenital birth anomaly with multifactorial etiology. The GREM1 gene has been proposed to play a role in oral clefts development.Objective: The aim of the present study was to evaluate the correlation between GREM1 polymorphisms and the risk of NSCL/P in an Iranian population.Methods: Genotyping of rs7162202, rs12915554, rs3743105, rs1129456, and rs10318 polymorphisms of GREM1 gene in 150 NSCL/P and 152 healthy subjects was determined by the PCR-RFLP or T-ARMS-PCR.Results: The findings showed that the rs12915554 variant significantly increased the risk of NSCL/P in heterozygous (OR = 4.20, 95%CI = 2.46-7.11, p < 0.0001, AC vs AA), and allele (OR = 3.17, 95%CI = 2.00-5.08, p < 0.0001, C vs A) genetic models. The rs3743105 polymorphism was correlated with reduced risk of NSCL/P in heterozygous (OR = 0.49, 95%CI = 0.29-0.83, p = 0.008, AG vs GG) and dominant (OR = 0.54, 95%CI = 0.33-0.89, p = 0.018, GA + AA vs GG) genetic models. The rs1129456 variant was positively associated with the risk of NSCL/P in heterozygous (OR = 2.91, 95%CI = 1.12-7.38, p = 0.028, AT vs AA) and allele (OR = 2.80, 95%CI = 2.80-6.95, p = 0.031, T vs C). The rs10318 polymorphism significantly reduced NSCL/P risk in homozygous (OR = 0.20, 95%CI = 0.06-0.67, p = 0.013, TT vs CC), dominant (OR = 0.57, 95%CI = 0.36-0.91, p = 0.019, CT + CC vs CC), recessive (OR = 0.24, 95%CI = 0.07-0.76, p = 0.031, TT vs CT + CC), and allele (OR = 0.57, 95%CI = 0.38-0.84, p = 0.005, T vs C). No correlation was observed between rs7162202 polymorphism and NSCL/P.Conclusion: The findings support that GREM1 polymorphisms are involved in NSCL/P susceptibility in an Iranian population.

Exosomes derived from P2X7 receptor gene-modified cells rescue inflammation-compromised periodontal ligament stem cells from dysfunction

Although cellular therapy has been proposed for inflammation‐related disorders such as periodontitis for decades, clinical application has been unsuccessful. One explanation for these disappointing results is that the functions of stem cells are substantially compromised when they are transplanted into an inflammatory in vivo milieu. Considering the previous finding that P2X7 receptor (P2X7R) gene modification is able to reverse inflammation‐mediated impairment of periodontal ligament stem cells (PDLSCs), we further hypothesized that cells subjected to P2X7R gene transduction also exert influences on other cells within an in vivo milieu via an exosome‐mediated paracrine mechanism. To define the paracrine ability of P2X7R gene‐modified cells, P2X7R gene‐modified stem cell‐derived conditional medium (CM‐Ad‐P2X7) and exosomes (Exs‐Ad‐P2X7) were used to incubate PDLSCs. In an inflammatory osteogenic microenvironment, inflammation‐mediated changes in PDLSCs were substantially reduced, as shown by quantitative real‐time PCR (qRT‐PCR) analysis, Western blot analysis, alkaline phosphatase (ALP) staining/activity assays, and Alizarin red staining. In addition, the Agilent miRNA microarray system combined with qRT‐PCR analysis revealed that miR‐3679‐5p, miR‐6515‐5p, and miR‐6747‐5p were highly expressed in Exs‐Ad‐P2X7. Further functional tests and luciferase reporter assays revealed that miR‐3679‐5p and miR‐6747‐5p bound directly to the GREM‐1 protein, while miR‐6515‐5p bound to the GREM‐1 protein indirectly; these effects combined to rescue inflammation‐compromised PDLSCs from dysfunction. Thus, in addition to maintaining their robust functionality under inflammatory conditions, P2X7R gene‐modified stem cells may exert positive influences on their neighbors via a paracrine mechanism, pointing to a novel strategy for modifying the harsh local microenvironment to accommodate stem cells and promote improved tissue regeneration.

Msx1 deficiency interacts with hypoxia and induces a morphogenetic regulation during mouse lip development

Nonsyndromic clefts of the lip and palate are common birth defects resulting from gene-gene and gene-environment interactions. Mutations in human MSX1 have been linked to orofacial clefting and we show here that Msx1 deficiency causes a growth defect of the medial nasal process (Mnp) in mouse embryos. Although this defect alone does not disrupt lip formation, Msx1-deficient embryos develop a cleft lip when the mother is transiently exposed to reduced oxygen levels or to phenytoin, a drug known to cause embryonic hypoxia. In the absence of interacting environmental factors, the Mnp growth defect caused by Msx1 deficiency is modified by a Pax9-dependent 'morphogenetic regulation', which modulates Mnp shape, rescues lip formation and involves a localized abrogation of Bmp4-mediated repression of Pax9 Analyses of GWAS data revealed a genome-wide significant association of a Gene Ontology morphogenesis term (including assigned roles for MSX1, MSX2, PAX9, BMP4 and GREM1) specifically for nonsyndromic cleft lip with cleft palate. Our data indicate that MSX1 mutations could increase the risk for cleft lip formation by interacting with an impaired morphogenetic regulation that adjusts Mnp shape, or through interactions that inhibit Mnp growth.

Understanding the participation of GREM1 polymorphisms in nonsyndromic cleft lip with or without cleft palate in the Brazilian population

BACKGROUND

GREM1, which encodes Gremlin 1, an antagonist of bone morphogenic proteins with effects on proliferation and apoptosis, has been considered a candidate gene for nonsyndromic cleft lip with or without cleft palate (NSCL±P). In this study, we investigated potential associations of single nucleotide polymorphisms (SNP) in GREM1 and NSCL±P risk in the Brazilian population. Additionally, SNP-SNP interactions of GREM1 with previously reported rs1880646 variant in NTN1 (netrin 1), a gene also responsible for apoptotic phenotypes were verified.

METHODS

Applying Taqman allelic discrimination assays, we evaluated the variants rs16969681, rs16969816, rs16969862, and rs1258763 in 325 case-parent trios and in 1,588 isolated samples in a case-control study. Allelic and genotypic analyses, as well as interaction tests assessing gene-environmental factor (GxE) and SNP-SNP interaction with rs1880646 variant in NTN1, were performed based on logistic regression analysis adjusted for the effects of gender and genomic ancestry proportions.

RESULTS

The risk alleles of all SNP were undertransmitted in NSCL±P trios, though the case-control analysis confirmed only the association with rs16969862 alleles (OR: 0.78, 95% CI: 0.63-0.96, p = .02). The GxE interaction analysis revealed a significant interaction between maternal environmental contact with agrotoxics and rs16969816 (OR: 0.25, 95% CI: 0.08-0.74, p = .01), and pairwise interaction test with NTN1 rs1880646 yielded significant p values in the 1,000 permutation test for rs16969681, rs16969816, and rs16969862.

CONCLUSION

The GREM1 is involved in the etiology of NSCL±P in the Brazilian population and reveal that the interaction between GREM1 and NTN1 may be related with the pathogenesis of this common craniofacial malformation.