We assessed genetic and environmental effects on bone development of the hand and wrist, and on key anthropometric measures in Chinese young twins. In total, 139 monozygotic and 95 dizygotic twin pairs aged from 5 to 18 years were recruited. The twin correlations of total hand and wrist scores for monozygotic (MZ) and dizygotic (DZ) twins were 0.71 and 0.36, respectively. Bivariate model analysis showed moderate genetic correlations only for total skeletal maturity vs. weight and total skeletal maturity vs. waist circumference (r, 0.51 and 0.46, respectively). Our findings demonstrated that genetic factors played important roles in bone development of the hand and wrist in Chinese young twins, and that these genetic effects might be distinct from those influencing anthropometric measures.
Adolescent ; Bone Development ; genetics ; Child ; Child, Preschool ; China ; Environmental Exposure ; Hand Bones ; growth & development ; Humans ; Twins, Dizygotic ; Twins, Monozygotic ; Wrist ; growth & development

Notch signaling is highly conserved in evolution and regarded as a key factor in cell fate determination. It mediates cell-to-cell interactions that are critical for embryonic development and tissue renewal, and is involved in the occurrence and metastasis of neoplasm. Recent researches have found that such signaling plays an important role in modulating the differentiation of chondrocytes, osteoblasts and osteoclasts. Dysfunction of Notch signaling can result in many skeletal diseases such as bone tumor, disorders of bone development or bone metabolism.
Animals ; Bone Development ; Bone Diseases ; genetics ; metabolism ; Bone and Bones ; metabolism ; Humans ; Osteoblasts ; cytology ; metabolism ; Osteogenesis ; Receptors, Notch ; genetics ; metabolism ; Signal Transduction

Skeletogenesis occurs through either intramembranous or endochondral ossification. In addition, some parts of the skeletal components maintain their cartilaginous characteristics throughout life without mineralization. Runx2 is known to be a pivotal transcription factor for all skeletogenic processes. In this study, we examined the expression patterns of two major isoforms of Runx2 in early skeletogenesis. During intramembranous bone formation, Runx2-type I (Runx2-I) was widely expressed in osteoprogenitor cells and active osteoblasts, while Runx2-type II (Runx2-II) expression was stringently restricted to cells lining mineralized bones. Cells in permanent cartilage expressed collagen type II (Col-II) but never expressed Runx2 or Col-X. These permanent cartilages were well circumscribed by Runx2-I positive cells, in which Runx2-II was negative. In endochondral bone formation, Runx2 expression temporarily disappeared in Col-II-positive proliferating chondrocytes, but a secondary surge of Runx2-I expression occurred in the prehypertrophic zone before the mineralization of cartilage. Collectively, both Runx2 isoforms showed very similar expression patterns in active bone forming areas; however, Runx2-I has an exclusive role in the early commitment stage of intramembranous or endochondral bone forming processes or in cells surrounding permanent cartilage.
Animals ; *Bone Development ; Cartilage/cytology/growth & development/metabolism ; Embryo and Fetal Development/genetics ; *Gene Expression Profiling ; *Gene Expression Regulation, Developmental ; In Situ Hybridization ; Mice ; Mice, Inbred ICR ; Protein Isoforms/genetics/metabolism ; Time Factors ; Transcription Factors/*genetics/metabolism

OBJECTIVETo observe dynamically the development of fetal long bone and detect the expression and distribution of HIF-1alpha,to investigate the expression pattern and possible effects of hypoxia inducible factor-1alpha (HIF-1alpha) in fetal long bone development of mouse.

METHODSE12.5, E13.5, E14.5, E15.5, E16.5 and E17.5 pregnant C57BL6 mice were sacrificed. After sacrifice, the embryos were delivered by caesarean section. The development of fetal long bone was dynamically observed by stereoscopic microscope, and the distributional expression of HIF-1alpha protein was detected by using method of immunohistochemistry. The expression of HIF-1alpha mRNA and osteoblast marker gene at various stage were also detected by using methods of reverse transcription-polymerase chain reaction (RT-PCR).

RESULTSThe cartilaginous long bone began to form and joints outline arised at E13.5, then the primary ossification center was observed at E14.5, showing opaque ossification under stereoscopic microscope,and then the osteogenesis expanded and extended to both sides. Immunohistochemistry demonstrated lots of HIF-1alpha protein positive chondrcytes in the center of primary ossification at E14.5, then they decreased dramatically. HIF-1alpha mRNA expressed at high level from E13.5 to E15.5, and then decreased to low level.

CONCLUSIONFetal long bone development pattern appeared to be endochondral osteogenisis process, existing hypoxia microenviroment may increase HIF-1alpha mRNA expression and thus initiate the cascade of endochondral osteogenisis.

Animals ; Bone Development ; Female ; Hypoxia-Inducible Factor 1, alpha Subunit ; analysis ; genetics ; physiology ; Immunohistochemistry ; Male ; Mice ; RNA, Messenger ; analysis

OBJECTIVETo investigate the association between estrogen receptor-alpha (ER-alpha) gene polymorphisms, pubertal bone mineral density (BMD) and bone turnover markers, to better understand the frequencies of ER-a genotypes.

METHODSThe ER-alpha Pvu II and Xba I genotypes were determined by PCR-RFLP in 158 healthy adolescent girls (12-14 years old) while BMD was measured by dual-energy X-ray absorptiometry (DEXA). The bone turnover markers (BAP, BGP, TRACP) and calcium adjust hormone (25-OH-VitD, E2) were detected by ELISA. The relationship among BMD, bone turnover markers, and polymorphisms of ER-a were examined.

RESULTS(1) Although the bone turnover markers had a trend in ER-alpha Pvu II genotypes as pp>PP>Pp but no significant difference was found (P > 0.05). There were no significant differences found among Xba I genotypes and between Px haplotype and non-Px haplotype. (2) No association was noticed between ER-a genotype and BMD at any site of the forearm and the whole body. Compared with non-Px haplotype, the Px haplotype had lower BMD, but there was no significant difference noticed (P > 0.05).

CONCLUSIONER-alpha gene Pvu II and Xba I polymorphism seemed not potentially influence on BMD and bone turnover markers in the pubertal girls in Beijing, suggesting that it might not be the major genetic factor regarding this population.

Absorptiometry, Photon ; Acid Phosphatase ; blood ; Adolescent ; Alkaline Phosphatase ; blood ; Bone Density ; genetics ; physiology ; Bone Development ; genetics ; Child ; China ; Enzyme-Linked Immunosorbent Assay ; Estrogen Receptor alpha ; genetics ; Female ; Genotype ; Haplotypes ; genetics ; Humans ; Osteocalcin ; blood ; Polymerase Chain Reaction ; Polymorphism, Genetic ; genetics ; Polymorphism, Restriction Fragment Length ; genetics ; Puberty ; blood ; genetics ; Vitamin D ; blood

Formation of the periodontium begins following onset of tooth-root formation in a coordinated manner after birth. Dental follicle progenitor cells are thought to form the cementum, alveolar bone and Sharpey's fibers of the periodontal ligament (PDL). However, little is known about the regulatory morphogens that control differentiation and function of these progenitor cells, as well as the progenitor cells involved in crown and root formation. We investigated the role of bone morphogenetic protein-2 (Bmp2) in these processes by the conditional removal of the Bmp2 gene using the Sp7-Cre-EGFP mouse model. Sp7-Cre-EGFP first becomes active at E18 in the first molar, with robust Cre activity at postnatal day 0 (P0), followed by Cre activity in the second molar, which occurs after P0. There is robust Cre activity in the periodontium and third molars by 2 weeks of age. When the Bmp2 gene is removed from Sp7(+) (Osterix(+)) cells, major defects are noted in root, cellular cementum and periodontium formation. First, there are major cell autonomous defects in root-odontoblast terminal differentiation. Second, there are major alterations in formation of the PDLs and cellular cementum, correlated with decreased nuclear factor IC (Nfic), periostin and α-SMA(+) cells. Third, there is a failure to produce vascular endothelial growth factor A (VEGF-A) in the periodontium and the pulp leading to decreased formation of the microvascular and associated candidate stem cells in the Bmp2-cKO(Sp7-Cre-EGFP). Fourth, ameloblast function and enamel formation are indirectly altered in the Bmp2-cKO(Sp7-Cre-EGFP). These data demonstrate that the Bmp2 gene has complex roles in postnatal tooth development and periodontium formation.
Actins ; analysis ; Activating Transcription Factor 2 ; genetics ; Age Factors ; Ameloblasts ; pathology ; Amelogenesis ; genetics ; Animals ; Bone Morphogenetic Protein 2 ; genetics ; Cell Adhesion Molecules ; analysis ; Cell Differentiation ; genetics ; Cementogenesis ; genetics ; Dental Cementum ; pathology ; Dental Pulp ; blood supply ; Fluorescent Dyes ; Green Fluorescent Proteins ; Male ; Mice ; Mice, Knockout ; Microvessels ; pathology ; Molar ; growth & development ; Molar, Third ; growth & development ; NFI Transcription Factors ; analysis ; Odontoblasts ; pathology ; Odontogenesis ; genetics ; Periodontal Ligament ; growth & development ; Sp7 Transcription Factor ; Stem Cells ; physiology ; Tooth Root ; growth & development ; Transcription Factors ; genetics ; Vascular Endothelial Growth Factor A ; analysis ; Zinc Fingers ; genetics

Congenital adrenal insufficiency is caused by specific genetic mutations. Early suspicion and definite diagnosis are crucial because the disease can precipitate a life-threatening hypovolemic shock without prompt treatment. This study was designed to understand the clinical manifestations including growth patterns and to find the usefulness of ACTH stimulation test. Sixteen patients with confirmed genotyping were subdivided into three groups according to the genetic study results: congenital adrenal hyperplasia due to 21-hydroxylase deficiency (CAH, n=11), congenital lipoid adrenal hyperplasia (n=3) and X-linked adrenal hypoplasia congenita (n=2). Bone age advancement was prominent in patients with CAH especially after 60 months of chronologic age (n=6, 67%). They were diagnosed in older ages in group with bone age advancement (P<0.05). Comorbid conditions such as obesity, mental retardation, and central precocious puberty were also prominent in this group. In conclusion, this study showed the importance of understanding the clinical symptoms as well as genetic analysis for early diagnosis and management of congenital adrenal insufficiency. ACTH stimulation test played an important role to support the diagnosis and serum 17-hydroxyprogesterone levels were significantly elevated in all of the CAH patients. The test will be important for monitoring growth and puberty during follow up of patients with congenital adrenal insufficiency.
17-alpha-Hydroxyprogesterone/blood ; 46, XY Disorders of Sex Development/drug therapy/*genetics ; Adolescent ; Adrenal Hyperplasia, Congenital/drug therapy/*genetics ; Adrenal Insufficiency/*congenital/diagnosis/drug therapy/genetics ; Adrenocorticotropic Hormone/*metabolism ; Bone Development/genetics ; Child ; Child, Preschool ; DAX-1 Orphan Nuclear Receptor/genetics ; Female ; Genetic Diseases, X-Linked/drug therapy/*genetics ; Genotype ; Glucocorticoids/therapeutic use ; Humans ; Intellectual Disability/complications ; Male ; Mineralocorticoids/therapeutic use ; Obesity/complications ; Phosphoproteins/genetics ; Puberty, Precocious/complications ; Retrospective Studies ; Steroid 21-Hydroxylase/genetics

OBJECTIVETo measure the osteogenesis and adipogenesis potentiality of rat marrow stromal cells (MSCs) derived from 3, 6, 9, 12-month-old doner rats.

METHODSRat MSCs were induced to osteoblast or adipocyte by osteogenic inducer or adipogenic inducer. In different times, 3 and 12-month-old rat MSCs were observed by histochemistry staining; the mRNA level of type I collagen and lipoprotein lipase of 3, 6, 9, 12-month-old rat MSCs were measured by RT-PCR.

RESULTSThe expression of alkaline phosphatase (ALP) of the control group and induced group of 12-month old rat MSCs was less than that of 3-month old rat MSCs after 1-week osteogenic induction. 12 days later, calcification was observed in 3-month old group. Lipid droplets occurred in the cells of 12-month old group after 2-day adipogenic induction, while these droplets occurred after 3-day or 4-day induction in 3-month old group. The mRNA level of type I collagen decreased with the increase of age. The mRNA level of lipoprotein lipase of younger rats was lower than that of older rats. Both of the changes were more significantly with the increase of the induction time.

CONCLUSIONSWith the increase of age, the ability of osteogenesis of rat MSCs decreased, but the ability of adipogenesis increased.

Adipose Tissue ; growth & development ; Aging ; Alkaline Phosphatase ; metabolism ; Animals ; Base Sequence ; Bone Marrow Cells ; cytology ; Cell Differentiation ; Cells, Cultured ; Collagen Type I ; biosynthesis ; genetics ; Female ; Lipoprotein Lipase ; biosynthesis ; genetics ; Molecular Sequence Data ; Osteogenesis ; RNA, Messenger ; biosynthesis ; genetics ; Rats ; Rats, Sprague-Dawley ; Stromal Cells ; cytology

The present study aimed at investigating the effects of Puerarin (PR), a major isoflavonoid isolated from the Chinese medicinal herb Puerariae radix, on bone metabolism and the underlying mechanism of action. The in vivo assay, female mice were ovariectomized (OVX), and the OVX mice were fed with a diet containing low, middle, and high doses of PR (2, 4, and 8 mg·d(-1), respectively) or 17β-estradiol (E2, 0.03 μg·d(-1)) for 4 weeks. In OVX mice, the uterine weight declined, and intake of PR at any dose did not affect uterine weight, compared with the control. The total femoral bone mineral density (BMD) was significantly reduced by OVX, which was reversed by intake of the diet with PR at any dose, especially at the low dose. In the in vitro assay, RAW264.7 cells were used for studying the direct effect of PR on the formation of osteoclasts. PR reduced the formation of tartrate resistant acid phosphatase (TRAP)-positive multi-nucleated cells in the RAW 264.7 cells induced by receptor activator for nuclear factor-κB Ligand (RANKL). MC3T3-E1 cells were used for studying the effects of PR on the expression of osteoprotegerin (OPG) and RANKL mRNA expression in osteoblasts. The expression of OPG mRNA and RANKL mRNA was detected by RT-PCR on Days of 5, 7, 10, and 12 after PR exposure. PR time-dependently enhanced the expression of OPG mRNA and reduced the expression of RANKL mRNA in MC3T3-E1 cells. In conclusion, our results suggest that PR can effectively prevent bone loss in OVX mice without any hyperplastic effect on the uterus, and the antiosteoporosis activity of PR may be related to its effects on the formation of osteoclasts and the expression of RANKL OPG in osteoblasts.
Animals ; Bone Density ; drug effects ; Drugs, Chinese Herbal ; administration & dosage ; Female ; Femur ; chemistry ; growth & development ; metabolism ; Humans ; Isoflavones ; administration & dosage ; Mice ; Osteoclasts ; drug effects ; metabolism ; Osteoporosis ; genetics ; metabolism ; physiopathology ; prevention & control ; Osteoprotegerin ; genetics ; metabolism ; Ovariectomy ; Pueraria ; chemistry ; RANK Ligand ; genetics ; metabolism

OBJECTIVETo investigate the effect of 7- dehydrocholesterol reductas (Dhcr-7) gene silencing on the palatal development by sonic hedgehog (Shh)-bone morphogenetic protein2(BMP-2) signal pathway in vitro.

METHODSA total of 60 pairs of palatal shelves fromgestation day (GD) 13.5 mouse embryos were divided into three groups (A, B, C) of 20 randomly. In group A (control), palatal shelves were cultured with medium containing no cholesterol.In group B (Dhcr-7-siRNA), palatal shelves were cultured without cholesterol medium but containing Dhcr-7 siRNA adenovirus. After 48h, the culture medium of groups A and B were changed with medium without cholesterol. In group C (cholesterol), palatal shelves were cultured without cholesterol medium but containing Dhcr-7 siRNA adenovirus. After 48h, the culture medium of group C was changed with medium containing 600 mg/L cholesterol. After 72h again, tissues dyeing and scanning electron microscope (SEM) technique were used to observe morphological changes of palates. Both RT-PCR and Western blottingtechniques were used to measure mRNA and protein expressions for Dhcr-7, Shh, and BMP-2, respectively.

RESULTSThe tissues dyeing and SEM showedthat the palates fusedin groups A and Candthe palates did not fuse in group B eventually. The expression of both mRNA and proteins for Shh and BMP-2 in group B wasdecreased with the Dhcr-7 reduction. In group B, the mRNA and protein expression of Shh was separately 0.063±0.018 and 0.092±0.065;the mRNA and protein expression quantity of BMP- 2 was separately 0.054±0.018 and 0.049±0.021. In group A, the mRNA and protein expression of Shh was separately 0.667±0.093 and 0.639±0.078;the mRNA and protein expression of BMP-2 was separately 0.591 ± 0.043 and 0.569 ± 0.081. The difference of Shh and BMP- 2 mRNA and protein expression between A and B group were statistically significant separately (P < 0.05). The expression of both mRNA and protein for Dhcr-7 (0.074±0.034 and 0.075±0.028) did not changebasicallyin group C, compared with the Dhcr- 7expression of mRNA and protein (0.083±0.045; 0.067±0.065) in group B, the difference wasnot statistically significant(P > 0.05). In group C, the mRNA and protein expressionof Shh (0.649±0.085 and 0.608±0.092) and BMP-2 (0.578±0.062 and 0.548±0.065) were significantly increased. The difference of Shh and BMP-2 mRNA and protein expression between B and C group were statistically significant separately (P < 0.05).

CONCLUSIONSDhcr-7 could influence the expression of Shh and BMP-2. Dhcr-7 reductase regulated the palatal development by the Shh-BMP-2 signal pathway.

Animals ; Bone Morphogenetic Protein 2 ; genetics ; metabolism ; Cholesterol ; Culture Media, Conditioned ; chemistry ; pharmacology ; Hedgehog Proteins ; genetics ; metabolism ; Mice ; Oxidoreductases Acting on CH-CH Group Donors ; metabolism ; Palate ; growth & development ; metabolism ; RNA, Messenger ; analysis ; metabolism ; RNA, Small Interfering ; metabolism ; Random Allocation ; Signal Transduction