OBJECTIVEReceptor activity-modifying proteins (RAMPs) determine the ligand specificity of the calcitonin receptor-like receptor (CRLR); co-expression of RAMP1 and CRLR results in a calcitonin gene related peptide (CGRP) receptor, whereas the association of RAMP2 or RAMP3 with CRLR gives an adrenomedullin(ADM) receptor. As CGRP and ADM may play a beneficial role in heart failure, this study aimed at the question whether RAMPs mRNAs are changed in heart failure.

METHODSSemi-quantitative reverse transcription-PCR (RT-PCR) was used to detect and quantify the mRNAs of RAMP1 and RAMP3 in the atria of heart failing patients.

RESULTSIt was found that the expressions of RAMP1, RAMP2 and RAMP3 mRNAs increased with the worsening of heart function, but the expressions of RAMP1 and RAMP2 mRNA decreased at level IV of heart failure.

CONCLUSIONThe above results demonstrated in the atria of heart failure patients an up-regulation of CGRP receptor by an increase of RAMP1 in association with CRLR and an up-regulation of ADM receptor by an increase of RAMP2 expression in association with CRLR, thus suggesting that CGRP and ADM receptors be playing a functional role in compensating the chronic heart failure in human.

Adult ; Calcitonin Receptor-Like Protein ; Female ; Heart Atria ; metabolism ; Heart Failure ; genetics ; physiopathology ; Humans ; Intracellular Signaling Peptides and Proteins ; genetics ; physiology ; Male ; Membrane Proteins ; genetics ; physiology ; Receptor Activity-Modifying Protein 1 ; Receptor Activity-Modifying Protein 2 ; Receptor Activity-Modifying Protein 3 ; Receptor Activity-Modifying Proteins ; Receptors, Adrenomedullin ; Receptors, Calcitonin ; genetics ; physiology ; Receptors, Calcitonin Gene-Related Peptide ; genetics ; physiology ; Receptors, Peptide ; genetics ; physiology ; Reverse Transcriptase Polymerase Chain Reaction

OBJECTIVETo investigate the influnce of receptor activity modifying protein 1(RAMP-1) overexpression on enhancing effect of calcitonin gene-related peptide on MG-63 cells proliferation.

METHODSCultured MG-63 osteoblasts in exponential phase of growth were randomly divided into three groups: RAMP-1 overexpression group, empty vector control group and negative control group. RAMP-1 eukaryotic expression vector was constructed and stably transfected into MG-63 cells. Realtime-polymerase chain reaction, Western blotting and immunofluroescence were used respectively to detect the expression of calcitonin receptor-like receptor (CRLR) in the cells and its distribution on cell membrane. The status of proliferation was detected respectively at 0, 24, 48, 72, 96 h by cell counting kit-8 (CCK-8) and cells were collected to analyze their cycle respectively at 0, 8, 16, 24 h by flow cytometry.

RESULTSCRLR protein and mRNA expression levels of MG-63 cells in RAMP-1 overexpression group were significantly higher than the other two groups (P < 0.05). The A value of RAMP-1 overexpression group at 24, 48, 72, 96 h were 0.628 ± 0.175, 0.896 ± 0.592, 1.055 ± 0.004, 1.179 ± 0.618, respectively, which were significantly higher than that of the other two groups (P < 0.05). The difference was most pronounced at 72 h. S-phase fraction of RAMP-1 overexpression group was (1.25 ± 0.13)%, (68.79 ± 0.56)%, (64.49 ± 1.59)%, (57.82 ± 0.75)%, respectively, which were significantly higher than the other two groups (P < 0.05). The difference was most pronounced at 8 h.

CONCLUSIONSRAMP-1 overexpression can promote CRLR distribution on MG-63 cell membrane and enhance CGRP's promotion effect on MG-63 cell proliferation.

Bone Neoplasms ; metabolism ; pathology ; Calcitonin Gene-Related Peptide ; genetics ; metabolism ; Cell Cycle ; Cell Line, Tumor ; Cell Proliferation ; Genetic Vectors ; Humans ; Osteosarcoma ; metabolism ; pathology ; RNA, Messenger ; metabolism ; Random Allocation ; Receptor Activity-Modifying Protein 1 ; genetics ; metabolism ; Transfection