Frequência alélica e potencial regulatório de polimorfismosno gene NELL1 em uma população da Bahia ­ Brasil / Allele frequency and regulatory potential of polimorphisms in NELL1 gene in a population of Bahia ­ Brazil

Introdução: o gene NELL1 codifica a proteína semelhante ao fator de crescimento epidérmico (do inglês Epidermal Growth factor (EGF)-like). GWASs e estudos de associação com genes candidatos têm sido utilizados para estabelecer a conexão entre polimorfismos de nucleotídeo único (SNP) no NELL1 e diversas doenças. Objetivo: descrever a frequência alélica e o potencial regulatório dos polimorfismos do gene NELL1, estudados em uma população de Salvador (Bahia, Brasil) e descrever a frequência desses polimorfismos e a associação com diversas doenças, em populações africana, ameríndia, asiática e europeia. Metodologia: 1094 participantes foram recrutados através do Programa de Controle da Asma e da Rinite Alérgica no Estado da Bahia (ProAR). Os indivíduos tiveram o DNA genômico extraído e genotipado, utilizando-se a plataforma Illumina. Os SNP foram consultados através da plataforma SeattleSec Annotation. As bases de dados NCBI, RegulomeDB e Haploview 4.2 foram utilizadas para as análises. Resultados: foram analisados 346 SNPs do gene NELL1. Desses, 53 SNPs tiveram o MAF variando entre 50% e 40% e função intrônica. Os SNPs rs10833465 (alelo A), rs908944 (alelo C), rs1516766 (alelo A), rs10766739 (alelo G) e rs11025878 (alelo G) apresentam uma pontuação de 3, de acordo com o banco do RegulomeDB. O SNP rs7117671, com pontuação 2b, pode ter impacto regulatório e funcional. 101 SNPs apresentaram o MAF entre 39% e 20%. Dos polimorfismos menos frequentes nessa população, 192 apresentaram um MAF entre 19% e 2%. Discussão: alguns SNPs, com diferentes frequências, apresentaram alta probabilidade de impacto funcional. Foram encontrados, na literatura, estudos de associação dos SNPs e osteoporose, doenças metabólicas, condições inflamatórias, doenças neuropsiquiátricas e tumores malignos. Conclusão: ospolimorfismos do gene NELL1 estudados apresentaram diferentes frequências na população desse estudo e tiveram seus alelos associados a doenças em diferentes populações. Sugere-se que sejam realizados mais estudos.

Introduction: the NELL1 gene encodes the epidermal growth factor (EGF)-like protein. GWASs and association studies with candidate genes have been used to establish the connection between single nucleotide polymorphisms (SNP) in NELL1 and various diseases. Objective: to describe the allele frequency and regulatory potential of NELL1 gene polymorphisms studied in a population from Salvador, Bahia, Brazil; and to describe the frequency of these polymorphisms, and the association with various diseases, in African, Amerindian, Asian and European populations. Methodology: one thousand and ninety-four (1094) participants were recruited through the Program for the Control of Asthma and Allergic Rhinitis in the State of Bahia (ProAR). Individuals had their genomic DNA extracted and genotyped using the Illumina platform. The SNPs were consulted through the SeattleSec Annotation platform. The NCBI, RegulomeDB and Haploview 4.2 databases were used for the analyses. Results: four hundred and seventy-three (346) NELL1 gene SNPs were analyzed. Of these, 53 SNPs had MAF ranging between 50% and 40% and intronic function. The SNPs rs10833465 (A allele), rs908944 (C allele), rs1516766 (A allele), rs10766739 (G allele) and rs11025878 (G allele) showed a score of 3, according to the RegulomeDB database. SNP rs7117671, with score 2b, may have regulatory and functional impact. One hundred and eighteen (101) SNPs presented MAF between 39% and 20%. Of the less frequent polymorphisms in this population, 192 had a MAF between 19% and 2%. Discussion: some SNPs, with different frequencies, presented a high probability of functional impact. Studies on the association of SNPs and osteoporosis, metabolic diseases, inflammatory conditions, neuropsychiatric diseases and malignant tumors were found in the literature. Conclusion: the NELL1 gene polymorphisms studied showed different frequencies in the population of this study and had their alleles associated with diseases in different populations. It is suggested that further studies be carried out.

Nell-1 in bone tissue engineering / 中国组织工程研究

BACKGROUND: Nel-like type 1 molecule (Nell-1) is a secreted glycoprotein that has been proven both in vitro and in vivo to be a potent osteoinductive factor that effectively promotes bone growth. Furthermore, it has been shown to repress adipogenic differentiation and inflammation. OBJECTIVE: To review the current research progress of Nell-1 in bone tissue engineering. METHODS: PubMed database was searched for relevant articles published from January 1996 to June 2019. Search words were “Nell-1; bone regeneration and repair; regulatory factor; signal path; bone morphogenetic protein; osteoporosis; marrow derived mesenchymal stem cells.” After removal of repetitive studies and inconsistent literature, 61 articles were finally analyzed. RESULTS AND CONCLUSION: Nell-1 has been proved to be a factor that can effectively promote bone tissue growth. Local application of Nell-1 has a good effect on the growth of long bone, spine and cartilage as well as cranial suture closure. Nell-1 is a new growth factor that has relatively simple bioeffects, so it has better biosafety and higher accuracy relative to the other bone growth factors. Nell-1 can synergize with other osteogenic factors such as bone morphogenetic proteins 2, 9. Nell-1 inhibits inflammatory reaction and lipogenesis induced by bone morphogenetic protein 2 and promotes osteogenesis. This provides a theoretical basis for the combination of Nell-1 and bone morphogenetic protein 2 to improve the clinical safety and efficacy in bone regeneration.

miR-27a protects human mitral valve interstitial cell from TNF-alpha-induced inflammatory injury via up-regulation of NELL-1

MicroRNAs (miRNAs) have been reported to be associated with heart valve disease, which can be caused by inflammation. This study aimed to investigate the functional impacts of miR-27a on TNF-α-induced inflammatory injury in human mitral valve interstitial cells (hMVICs). hMVICs were subjected to 40 ng/mL TNF-α for 48 h, before which the expressions of miR-27a and NELL-1 in hMVICs were altered by stable transfection. Trypan blue staining, BrdU incorporation assay, flow cytometry detection, ELISA, and western blot assay were performed to detect cell proliferation, apoptosis, and the release of proinflammatory cytokines. We found that miR-27a was lowly expressed in response to TNF-α exposure in hMVICs. Overexpression of miR-27a rescued hMVICs from TNF-α-induced inflammatory injury, as cell viability and BrdU incorporation were increased, apoptotic cell rate was decreased, Bcl-2 was up-regulated, Bax and cleaved caspase-3/9 were down-regulated, and the release of IL-1β, IL-6, and MMP-9 were reduced. NELL-1 was positively regulated by miR-27a, and NELL-1 up-regulation exhibited protective functions during TNF-α-induced cell damage. Furthermore, miR-27a blocked JNK and Wnt/β-catenin signaling pathways, and the blockage was abolished when NELL-1 was silenced. This study demonstrated that miR-27a overexpression protected hMVICs from TNF-α-induced cell damage, which might be via up-regulation of NELL-1 and thus modulation of JNK and Wnt/β-catenin signaling pathways.

NELL-1:a novel highly efficient and specific growth factor / 北京大学学报(医学版)

SUMMARY Regenerationofbonetissue,aswellasothertissues,requiresinvolvementandinteraction of cells,scaffolds and relevant growth factors,among which growth factors play a crucial role in maintai-ning the stability of microenvironment.Nel-like-type 1 molecule (NELL-1 ),a novel growth factor in tis-sue engineering,has been studied intensively in recent years.Researches mainly covered gene and pro-tein structure and their expression profiling,biological function,molecular mechanisms and disease rele-vance.NELL-1 expressed in embryonic tissue is essential for growth and development of bone tissue. NELL-1 presents excellent abilities of inducing bone and cartilage regeneration,especially with high spe-cificity to chondrocyte lineage.Compared with classic osteogenic growth factor bone morphogenetic pro-tein 2 (BMP-2),the process of osteogenesis interacted with NELL-1 exhibits stronger specificity,higher bone density and fewerside effects.Furthermore,a recent study shows synergistic effects of NELL-1 and BMP-2.NELL-1 enhances the osteogenic reaction induced by BMP-2 of cells and notably declines in-flammation response caused by BMP-2.This review evaluates the current research progress of the function and application of NELL-1 by the systematic method of evidence-based medicine.

Nell-1 transferred BMSC combined with absorbable fibrin glue repairs mandible defect in dogs / 第三军医大学学报

Objective To explore the effect of bone marrow stromal cells (BMSC) transferred by Nell-1 gene combined with biomaterial fibrin glue (FG) to enhance segmental bone defect healing in dog mandible. Methods Nell-1 gene vector was reconstructed in retroviral vector and then transfected BMSC. The protein of Nell-1 gene in transferred cells was determined by immunohistochemistry. Segmental defects were created surgically in the dog’s mandible. The defect was repaired with BMSC transfected by Nell-1 retroviral granules in presence of FG,untransfected BMSC in combination with FG,and FG alone. The control group was left untreated. The defect-repairing capability for each treatment were assessed by gross observation,radiography,and histology at 8th week and 16th week. Results Cells transfected by Nell-1 retroviral granules expressed abundant Nell-1 mRNA and protein in the cytoplasm. Positive results were not found in those cells that were not transferred. The use of BMSC transferred by Nell-1 retroviral granules combined with FG materials exhibited the strongest defect-repairing ability. Gross observation,radiographical and histomorphometric analyses revealed a significantly greater total area of bone formation,increased amount of the new bone in the defects than in those treated with the untransfected BMSC. Conclusion Nell-1 gene transfection may be used to promote the osteogenic ability of BMSC.