Pulmonary arterial hypertension is caused by vascular remodeling including muscularization of arteries, loss of small precapillary arteries, and formation of neointima and plexiform lesion, resulting in a progressive increase in pulmonary vascular resistance. About 70% of heritable pulmonary arterial hypertension and 10% to 40% of idiopathic pulmonary arterial hypertension patients possess mutations in bone morphogenetic protein receptor, type 2 (BMPR2), which is a type II receptor of TGF-beta superfamily. Very rarely, mutations in another receptors of TGF-beta superfamily, activin-like kinase-type 1 (ALK1) and endoglin (ENG) are found in pulmonary arterial hypertension patients with hereditary hemorrhagic telangiectasia. Genetic screening is useful to identify family members who are mutation carriers in heritable pulmonary arterial hypertension families.
Arteries ; Bone Morphogenetic Protein Receptors, Type II ; Bone Morphogenetic Proteins ; Genetic Testing ; Humans ; Hypertension ; Hypertension, Pulmonary ; Neointima ; Telangiectasia, Hereditary Hemorrhagic ; Transforming Growth Factor beta ; Vascular Resistance

Humans ; Pulmonary Arterial Hypertension ; Bone Morphogenetic Protein Receptors, Type II/metabolism* ; Pedigree ; Mutation ; Familial Primary Pulmonary Hypertension

OBJECTIVETo study the feasibility of osteogenic phenotype expression by human skin fibroblasts induced in polyglycolic acid (PGA) foams and the effect of tumor necrosis factor-alpha (TNF-alpha) on the expression of bone morphogenetic protein (BMP) receptors.

METHODSThe fibroblasts were isolated, purified from human skin. (1) Fibroblasts were seeded onto PGA foams. The cell-PGA complexes were cultured in RCCS for 6 weeks, in the media of TNF-alpha (50 U/ml) and BMP-2 (0.1 microg/ml). 1 d, 3 and 6 weeks later, cells and extracellular matrix were investigated by electron microscopic and histochemistry observation respectively. Secretion of osteogenic markers were analyzed by biochemical methods. (2) Fibroblasts were seeded on the glass fragments or culture flasks and treated with TNF-alpha (50 U/ml) in different usage (one-time, all-time). The RT-PCR method and the immunohistochemistry fluorescence staining were used to examine the influence of TNF-alpha on the mRNA expression and the protein expression of the type I BMP receptors at 2, 4, 6, 8 d after treatment.

RESULTSFibroblasts seeded on the PGA foams formed 3-dimensional matrix 3 weeks after seeding, which was demonstrated as osteo-tissue by tetracycline labeling and ARS staining. Cells secreted much more bone-specific alkaline phosphatase (B-AKP) and osteocalcin (OCN) into supernatant than the cells that were cultured in the media without TNF-a and BMP2. Eight days after all-time usage, the TNF-alpha (50 U/ml) increased the expression of the mRNA and protein of the type IB BMP receptor.

CONCLUSIONSFibroblasts on 3-D cell-foam structures can express osteoblastic phenotype under certain inducing conditions. The numerous fibroblasts in body would be a promising resource for cell seeds candidate of tissue- engineered bone. TNF-alpha provides the essential condition for BMP2's target effect on fibroblasts, and combined use of TNF-alpha and BMP2 is one of the regulating factors.

Bone Morphogenetic Protein 2 ; Bone Morphogenetic Protein Receptors, Type I ; biosynthesis ; genetics ; Bone Morphogenetic Protein Receptors, Type II ; biosynthesis ; genetics ; Bone Morphogenetic Proteins ; pharmacology ; Cell Culture Techniques ; methods ; Cell Differentiation ; drug effects ; Cells, Cultured ; Drug Synergism ; Fibroblasts ; cytology ; drug effects ; metabolism ; Humans ; Phenotype ; Polyglycolic Acid ; Transforming Growth Factor beta ; pharmacology ; Tumor Necrosis Factor-alpha ; pharmacology

BACKGROUNDFamilial pulmonary arterial hypertension (FPAH) is an autosomal dominant disorder characterized by plexiform lesions of endothelial cells in pulmonary arterioles which leads to elevated pulmonary arterial pressure, right-sided heart failure and death. Heterozygous mutations in the bone morphogenetic protein type II receptor gene (BMPR2) have been found to underlie a majority of FPAH cases. More than 140 distinct mutations have been identified in FPAH cases and in idiopathic pulmonary arterial hypertension (IPAH) cases, but only one mutation has been reported in Chinese patients.

METHODSA three-generation pedigree of FPAH and another 10 patients with IPAH were collected. In the family, two of the 9 surviving and one deceased family member were diagnosed as FPAH. The entire protein-coding region and intron/exon boundaries of the BMPR2 gene were amplified by PCR using DNA samples from affected individuals. Direct sequencing of PCR products was performed on both the sense and antisense strands. To confirm the segregation of the mutation within the family and exclude the presence of the mutation in normal subjects, the relevant exon was amplified by PCR, followed by mutation-specific RPLP analysis.

RESULTSIn the Chinese pedigree with FPAH an A-to-T transition at position 1157 in exon 9 of the BMPR2 gene was identified which resulted in a Glu386Val mutation. We confirmed the segregation of the mutation within the family and excluded the presence of the mutation in a panel of 200 chromosomes from normal subjects. No mutation was detected in BMPR2 in the other 10 patients with IPAH.

CONCLUSIONSThis amino acid substitution occurs at a glutamic acid that is highly conserved in all type II TGF-beta receptors. The nearly invariant Glu forms an ion pair with an invariant Arg at position 491 thereby helping to stabilize the large lobe. Substitution of Arg at position 491 is the most frequently observed missense mutation in FPAH, but until now no mutations at position 386 have been found in FPAH. The predicted functional impact of the Glu386Val mutation and its absence in healthy controls support the mutation as the cause of FPAH.

Adolescent ; Amino Acid Sequence ; Bone Morphogenetic Protein Receptors, Type II ; genetics ; Child ; Child, Preschool ; Female ; Humans ; Hypertension, Pulmonary ; genetics ; Infant ; Male ; Molecular Sequence Data ; Mutation ; Pedigree

The occurrence and development of pulmonary arterial hypertension (PAH) is closely related to the genetic mutation of bone morphogenetic protein receptor type II (BMPRII) encoding gene and the inflammatory response mediated by nuclear factor κB (NF-κB) pathway. This paper was aimed to investigate the effect of NF-κB pathway inhibitors on lipopolysaccharide (LPS)-induced pulmonary artery endothelial cell injury. Human pulmonary artery endothelial cells were treated with 1 μg/mL of LPS. The expression levels of BMPRII and interleukin-8 (IL-8) were detected by Western blot and qPCR. The rat PAH model was established by intraperitoneal (i.p.) injection of monocrotaline (MCT). The expression levels of BMPRII and IL-8 in pulmonary artery endothelial cells were detected by immunofluorescence staining. Cardiac hemodynamic changes and pulmonary vascular remodeling were detected in the MCT-PAH model rats. The results showed that LPS caused down-regulation of BMPRII expression and up-regulation of IL-8 expression in human pulmonary artery endothelial cells. NF-κB inhibitor BAY11-7082 (10 μmol/L) reversed the effect of LPS. In the pulmonary artery endothelial cells of MCT-PAH model, BMPRII expression was down-regulated, IL-8 expression was up-regulated, weight ratio of right ventricle to left ventricle plus septum [RV/(LV+S)] and right ventricular systolic pressure (RVSP) were significantly increased, cardiac output (CO) and tricuspid annular plane systolic excursion (TAPSE) were significantly reduced, and pulmonary vessel wall was significantly thickened. BAY11-7082 (5 mg/kg, i.p., 21 consecutive days) reversed the above changes in the MCT-PAH model rats. These results suggest that LPS down-regulates the expression level of BMPRII through NF-κB signaling pathway, promoting the occurrence and development of PAH. Therefore, the NF-κB pathway can be used as a potential therapeutic target for PAH.
Animals ; Bone Morphogenetic Protein Receptors, Type II ; Down-Regulation ; Endothelial Cells/metabolism* ; Humans ; Hypertension, Pulmonary/drug therapy* ; Lipopolysaccharides ; NF-kappa B/metabolism* ; Rats ; Rats, Sprague-Dawley ; Vascular Remodeling

Bone Morphogenetic Protein Receptors, Type II ; metabolism ; Endothelium ; drug effects ; metabolism ; Hypertension, Pulmonary ; drug therapy ; metabolism ; pathology ; Signal Transduction ; drug effects

Human telomerase reverse transcriptase (hTERT) plays a central role in telomere lengthening for continuous cell proliferation, but it remains unclear how extracellular cues regulate telomerase lengthening of telomeres. Here we report that the cytokine bone morphogenetic protein-7 (BMP7) induces the hTERT gene repression in a BMPRII receptor- and Smad3-dependent manner in human breast cancer cells. Chonic exposure of human breast cancer cells to BMP7 results in short telomeres, cell senescence and apoptosis. Mutation of the BMPRII receptor, but not TGFbRII, ACTRIIA or ACTRIIB receptor, inhibits BMP7-induced repression of the hTERT gene promoter activity, leading to increased telomerase activity, lengthened telomeres and continued cell proliferation. Expression of hTERT prevents BMP7-induced breast cancer cell senescence and apoptosis. Thus, our data suggest that BMP7 induces breast cancer cell aging by a mechanism involving BMPRII receptor- and Smad3-mediated repression of the hTERT gene.
Actin-Related Protein 2 ; genetics ; metabolism ; Activin Receptors, Type II ; genetics ; metabolism ; Bone Morphogenetic Protein 7 ; genetics ; metabolism ; Bone Morphogenetic Protein Receptors, Type II ; genetics ; metabolism ; Breast Neoplasms ; genetics ; metabolism ; Cellular Senescence ; Female ; HeLa Cells ; Humans ; MCF-7 Cells ; Neoplasm Proteins ; genetics ; metabolism ; Protein-Serine-Threonine Kinases ; genetics ; metabolism ; Receptor, Transforming Growth Factor-beta Type II ; Receptors, Transforming Growth Factor beta ; genetics ; metabolism ; Smad3 Protein ; genetics ; metabolism ; Telomerase ; genetics ; metabolism ; Telomere Homeostasis

OBJECTIVETo study the role of antenatal glucocorticoid (dexamethasone and betamethasone) on bone morphogenetic protein (BMP) signal transduction of the rat fetal lungs.

METHODSFifteen pregnant rats were randomly divided into five groups: the rats treated with dexamethasone for 1 day (1D-DEX) or 3 days (3D-DEX), with betamethasone for 1 day (1D-BEX) or 3 days (3D-BEX) or with normal saline (control group), followed cesarean section on the 19th day of gestation. The mRNA levels of BMP4, BMPR-II, Smad1 and ATF-2 of fetal rat lungs were ascertained by reverse transcriptase polymerase chain reaction (RT-PCR). The expression of BMP4, BMPR-II, Smad1 and ATF-2 antigen expression in fetal lungs was assessed by immune histochemical staining. The expression of BMP4 and BMPR-II was determined by Western blot.

RESULTSThe levels of BMP4, BMPR-II and Smad1 mRNA expression were up-regulated in the 1D-BEX, 3D-BEX and 3D-DEX groups compared with those in the control group (P<0.05). The immune histochemiscal analysis showed that the expression of BMP4, BMPR-II, Phospho-Smad1 (pSmad1) and ATF-2 in the 1D-BEX, 3D-BEX and 3D-DEX groups was significantly higher than that in the control group (P<0.01). The results of Western blot demonstrated that the expression of BMP4 and BMPR-II protein increased significantly in the 1D-BEX, 3D-BEX and 3D-DEX groups when compared with the control group (P<0.01).

CONCLUSIONSBetamethasone and dexamethasone may play important roles in the regulation of BMP signal transduction in the rat fetal lungs. Up-regulation of BMP4, BMPR-II and Smad1 might be one of crucial factors for the glucocorticoid-induced maturity of fetal lungs.

Activating Transcription Factor 2 ; analysis ; genetics ; Animals ; Betamethasone ; pharmacology ; Bone Morphogenetic Protein 4 ; analysis ; genetics ; physiology ; Bone Morphogenetic Protein Receptors, Type II ; analysis ; genetics ; Dexamethasone ; pharmacology ; Female ; Fetus ; drug effects ; metabolism ; Lung ; drug effects ; metabolism ; Pregnancy ; Rats ; Rats, Sprague-Dawley ; Reverse Transcriptase Polymerase Chain Reaction ; Signal Transduction ; drug effects ; Smad1 Protein ; analysis ; genetics