Identification of microRNAs targeting vitamin D receptor and their effect on parathyroid hormone secretion in secondary hyperparathyroidism / 南方医科大学学报

OBJECTIVE@#To identify the miRNAs targeting vitamin D receptor (VDR) gene and their effect on parathyroid hormone (PTH) secretion in secondary hyperparathyroidism.@*METHODS@#Primary parathyroid cells with secondary hyperparathyroidism were isolated by collagenase digestion and cultured. The miRNAs targeting VDR were screened by bioinformatics methods and full transcriptome sequencing, and dual-luciferase reporter assay was used to verify the targeting relationship between VDR and the screened miRNA. The effects of overexpression or inhibition of the candidate miRNA on VDR mRNA and protein expressions and PTH secretion were evaluated using qRT-PCR and Western blotting. The expression levels of the candidate miRNAs and VDR mRNA in clinical specimens of parathyroid tissues were verified by qRT-PCR, and the expression of VDR protein was detected by immunohistochemistry.@*RESULTS@#We successfully isolated primary parathyroid cells. Dual-luciferase reporter assay verified the targeting relationship of hsa-miR-149-5p, hsa-miR-221-5p, hsa-miR-222-3p, hsa-miR-29a-5p, hsa-miR-301a-5p, hsa-miR-873-5p, hsa-miR-93-3p with VDR, and among them, the overexpression of hsa-miR-149-5p and hsa-miR-301a-5p significantly increased PTH secretion in the parathyroid cells. In patients with secondary hyperparathyroidism, hsa-miR-149-5p was highly expressed in the parathyroid tissues (P=0.046), where the expressions of VDR mRNA (P=0.0267) and protein were both decreased.@*CONCLUSION@#The two miRNAs, hsa-miR-149-5p and hsa-miR-301a-5p, may promote the secretion of PTH in patients with secondary hyperparathyroidism by down-regulating the expression of VDR gene.

Neoplasias endocrinas múltiples: un modelo clínico para aplicar técnicas de genética molecular / Multiple endocrine neoplasia: a clinical model for testing molecular genetic techniques

Multiple endocrine neoplasias (MEN) are syndromes inherited as autosomal dominant. The application of the techniques of molecular biology has made possible the identification of the genes causing MEN 1 and 2. The gene responsable for MEN 1 belongs to the family of tumor suppressor genes and encodes for a protein named MENIN whose function remains to be elucidated. The identification of mutant MEN 1 gene carriers who are at risk of developing this syndrome requires frequent biochemical screening for the development of endocrine tumors. MEN 2 is a consequence of mutations in the Ret proto- oncogene (c-Ret). This gene encodes for a tyrosine kinase receptor thought to play a role in the development of neural crest- derived tissue. Members of kindred with either MEN 2A or MEN 2B should be screened by direct DNA testing early in life for mutations in c-Ret. Those with the mutation should be advised to have thyroidectomy at five years of age in children with MEN 2A and earlier in children with MEN 2B . Some cases of sporadic MTC are actually MEN 2A or Familial MTC after c-Ret testing is done, therefore routine application of this test is recommended in all cases of apparent sporadic MTC