-
Noriaki Koyama,
Masako Miura,
Kazumasa Nakao, Eri Kondo,
Toshihito Fujii,
Daisuke Taura,
Naotetsu Kanamoto,
Masakatsu Sone,
Akihiro Yasoda,
Hiroshi Arai,
Kazuhisa Bessho,
Kazuwa Nakao
[show abstract]
[hide abstract]
ABSTRACT: Human induced pluripotent stem cells (hiPSCs) exhibit pluripotency, proliferation capability, and gene expression similar to those of human embryonic stem cells (hESCs). hESCs readily form cartilaginous tissues in teratomas in vivo; despite extensive effort, however, to date no efficient method for inducing mature chondrocytes in vitro has been established. hiPSCs can also differentiate into cartilage in vivo by teratoma formation, but as with hESCs, no reliable system for in vitro chondrogenic differentiation of hiPSCs has yet been reported. Here, we examined the chondrogenic differentiation capability of hiPSCs using a multistep culture method consisting of embryoid body (EB) formation, cell outgrowth from EBs, monolayer culture of sprouted cells from EBs, and 3-dimensional pellet culture. In this culture process, the cell density of monolayer culture was critical for cell viability and subsequent differentiation capability. Monolayer-cultured cells exhibited fibroblast-like morphology and expressed markers for mesenchymal stem cells. After 2-3 weeks of pellet culture, cells in pellets exhibited a spherical morphology typical of chondrocytes and were surrounded by extracellular matrix that contained acidic proteoglycans. The expression of type II collagen and aggrecan in pellets progressively increased. Histological analysis revealed that over 70% of hiPSC-derived pellets successfully underwent chondrogenic differentiation. Using the same culture method, hESCs showed similar histological changes and gene expression, but differentiated slightly faster and more efficiently than hiPSCs. Our study demonstrates that hiPSCs can be efficiently differentiated into the chondrogenic lineage in vitro via generation of mesenchymal progenitor cells, using a simplified, multistep culture method.
Stem cells and development 07/2012; · 4.15 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Long bone abnormality (lbab/lbab) is a strain of dwarf mice. Recent studies revealed that the phenotype is caused by a spontaneous mutation in the Nppc gene, which encodes mouse C-type natriuretic peptide (CNP). In this study, we analyzed the chondrodysplastic skeletal phenotype of lbab/lbab mice. At birth, lbab/lbab mice are only slightly shorter than their wild-type littermates. Nevertheless, lbab/lbab mice do not undergo a growth spurt, and their final body and bone lengths are only ~60% of those of wild-type mice. Histological analysis revealed that the growth plate in lbab/lbab mice, especially the hypertrophic chondrocyte layer, was significantly thinner than in wild-type mice. Overexpression of CNP in the cartilage of lbab/lbab mice restored their thinned growth plate, followed by the complete rescue of their impaired endochondral bone growth. Furthermore, the bone volume in lbab/lbab mouse was severely decreased and was recovered by CNP overexpression. On the other hand, the thickness of the growth plate of lbab/+ mice was not different from that of wild-type mice; accordingly, impaired endochondral bone growth was not observed in lbab/+ mice. In organ culture experiments, tibial explants from fetal lbab/lbab mice were significantly shorter than those from lbab/+ mice and elongated by addition of 10(-7) M CNP to the same extent as lbab/+ tibiae treated with the same dose of CNP. These results demonstrate that lbab/lbab is a novel mouse model of chondrodysplasia caused by insufficient CNP action on endochondral ossification.
Calcified Tissue International 01/2012; 90(4):307-18. · 2.38 Impact Factor
-
Megumi Inuzuka,
Naohisa Tamura,
Masakatsu Sone,
Daisuke Taura,
Takuhiro Sonoyama,
Kyoko Honda,
Katsutoshi Kojima,
Yorihide Fukuda,
Yoriko Ueda,
Yui Yamashita, Eri Kondo,
Go Yamada,
Toshihito Fujii,
Masako Miura,
Naotetsu Kanamoto,
Akihiro Yasoda,
Hiroshi Arai,
Yoshiki Mikami,
Hironobu Sasano,
Kazuwa Nakao
[show abstract]
[hide abstract]
ABSTRACT: Myelolipomas are adrenal tumors composed of both adipose and hematopoietic tissues which are rarely associated with primary aldosteronism (PA). Here, we report a case of myelolipoma associated with PA. Aldosterone hypersecretion from bilateral adrenal glands had been confirmed by adrenal venous sampling and pathological analyses, but PA was clinically cured after surgical removal of the unilateral adrenal gland together with the myelolipoma that was not producing aldosterone. It is suggested that myelolipomas may release some factors which stimulate aldosterone production in adrenal glands, although further investigation is necessary. Obesity-related hyperaldosteronism might in part participate in generation of hypertension in the present case.
Internal Medicine 01/2012; 51(5):479-85. · 0.94 Impact Factor
-
Toshihito Fujii,
Yasato Komatsu,
Akihiro Yasoda, Eri Kondo,
Tetsuro Yoshioka,
Takuo Nambu,
Naotestu Kanamoto,
Masako Miura,
Naohisa Tamura,
Hiroshi Arai,
Masashi Mukoyama,
Kazuwa Nakao
[show abstract]
[hide abstract]
ABSTRACT: C-type natriuretic peptide (CNP) is a potent stimulator of endochondral bone growth through a subtype of membranous guanylyl cyclase receptor, GC-B. Although its two cognate natriuretic peptides, ANP and BNP, are cardiac hormones produced from heart, CNP is thought to act as an autocrine/paracrine regulator. To elucidate whether systemic administration of CNP would be a novel medical treatment for chondrodysplasias, for which no drug therapy has yet been developed, we investigated the effect of circulating CNP by using the CNP transgenic mice with an increased circulating CNP under the control of human serum amyloid P component promoter (SAP-Nppc-Tg mice). SAP-Nppc-Tg mice developed prominent overgrowth of bones formed through endochondral ossification. In organ culture experiments, the growth of tibial explants of SAP-Nppc-Tg mice was not changed from that of their wild-type littermates, exhibiting that the stimulatory effect on endochondral bone growth observed in SAP-Nppc-Tg mice is humoral. Then we crossed chondrodysplastic CNP-depleted mice with SAP-Nppc-Tg mice. Impaired endochondral bone growth in CNP knockout mice were considerably and significantly recovered by increased circulating CNP, followed by the improvement in not only their longitudinal growth but also their body weight. In addition, the mortality of CNP knockout mice was greatly decreased by circulating CNP. Systemic administration of CNP might have therapeutic potential against not only impaired skeletal growth but also other aspects of impaired growth including impaired body weight gain in patients suffering from chondrodysplasias and might resultantly protect them from their early death.
Endocrinology 09/2010; 151(9):4381-8. · 4.46 Impact Factor
-
Takei Kake,
Hidetomo Kitamura,
Yuichiro Adachi,
Tetsuro Yoshioka,
Tomoyuki Watanabe,
Hiroaki Matsushita,
Toshihito Fujii, Eri Kondo,
Takanori Tachibe,
Yosuke Kawase,
Kou-ichi Jishage,
Akihiro Yasoda,
Masashi Mukoyama,
Kazuwa Nakao
[show abstract]
[hide abstract]
ABSTRACT: C-type natriuretic peptide (CNP) plays a critical role in endochondral ossification through guanylyl cyclase-B (GC-B), a natriuretic peptide receptor subtype. Cartilage-specific overexpression of CNP enhances skeletal growth and rescues the dwarfism in a transgenic achondroplasia model with constitutive active mutation of fibroblast growth factor receptor-3. For future clinical application, the efficacy of CNP administration on skeletal growth must be evaluated. Due to the high clearance of CNP, maintaining a high concentration is technically difficult. However, to model high blood CNP concentration, we established a liver-targeted CNP-overexpressing transgenic mouse (SAP-CNP tgm). SAP-CNP tgm exhibited skeletal overgrowth in proportion to the blood CNP concentration and revealed phenotypes of systemic stimulation of cartilage bones, including limbs, paws, costal bones, spine, and skull. Furthermore, in SAP-CNP tgm, the size of the foramen magnum, the insufficient formation of which results in cervico-medullary compression in achondroplasia, also showed significant increase. CNP primarily activates GC-B, but under high concentrations it cross-reacts with guanylyl cyclase-A (GC-A), a natriuretic peptide receptor subtype of atrial natriuretic peptides (ANP) and brain natriuretic peptides (BNP). Although activation of GC-A could alter cardiovascular homeostasis, leading to hypotension and heart weight reduction, the skeletal overgrowth phenotype in the line of SAP-CNP tgm with mild overexpression of CNP did not accompany decrease of systolic blood pressure or heart weight. These results suggest that CNP administration stimulates skeletal growth without adverse cardiovascular effect, and thus CNP could be a promising remedy targeting achondroplasia.
AJP Endocrinology and Metabolism 10/2009; 297(6):E1339-48. · 4.75 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Skeletal dysplasias are a group of genetic disorders characterized by severe impairment of bone growth. Various forms of them add to produce a significant morbidity and mortality, yet no efficient drug therapy has been developed to date. We previously demonstrated that C-type natriuretic peptide (CNP), a member of the natriuretic peptide family, is a potent stimulator of endochondral bone growth. Furthermore, we exhibited that targeted overexpression of a CNP transgene in the growth plate rescued the impaired bone growth observed in a mouse model of achondroplasia (Ach), the most frequent form of human skeletal dysplasias, leading us to propose that CNP may prove to be an effective treatment for this disorder. In the present study, to elucidate whether or not the systemic administration of CNP is a novel drug therapy for skeletal dysplasias, we have investigated the effects of plasma CNP on impaired bone growth in Ach mice that specifically overexpress CNP in the liver under the control of human serum amyloid P component promoter or in those treated with a continuous CNP infusion system. Our results demonstrated that increased plasma CNP from the liver or by iv administration of synthetic CNP-22 rescued the impaired bone growth phenotype of Ach mice without significant adverse effects. These results indicate that treatment with systemic CNP is a potential therapeutic strategy for skeletal dysplasias, including Ach, in humans.
Endocrinology 04/2009; 150(7):3138-44. · 4.46 Impact Factor
-
BMC Pharmacology. 01/2009;
-
[show abstract]
[hide abstract]
ABSTRACT: Long bone abnormality (lbab/lbab) is a spontaneous mutant mouse characterized by dwarfism with shorter long bones. A missense mutation was reported in the Nppc gene, which encodes C-type natriuretic peptide (CNP), but it has not been confirmed whether this mutation is responsible for the dwarf phenotype. To verify that the mutation causes the dwarfism of lbab/lbab mice, we first investigated the effect of CNP in lbab/lbab mice. By transgenic rescue with chondrocyte-specific expression of CNP, the dwarf phenotype in lbab/lbab mice was completely compensated. Next, we revealed that CNP derived from the lbab allele retained only slight activity to induce cGMP production through its receptor. Histological analysis showed that both proliferative and hypertrophic zones of chondrocytes in the growth plate of lbab/lbab mice were markedly reduced. Our results demonstrate that lbab/lbab mice have a hypomorphic mutation in the Nppc gene that is responsible for dwarfism caused by impaired endochondral ossification.
Biochemical and Biophysical Research Communications 10/2008; 376(1):186-90. · 2.48 Impact Factor
-
Hiroshi Arai,
Nozomi Kobayashi,
Yuko Nakatsuru,
Hiroaki Masuzaki,
Takuo Nambu,
Kazuhiko Takaya,
Yusuke Yamanaka, Eri Kondo,
Go Yamada,
Toshihito Fujii,
Masako Miura,
Yasato Komatsu,
Naotetsu Kanamoto,
Hiroyuki Ariyasu,
Kenji Moriyama,
Akihiro Yasoda,
Kazuwa Nakao
[show abstract]
[hide abstract]
ABSTRACT: This report concerns a case of cortisol-producing adrenocortical adenoma without the phenotype of Cushing's syndrome. A left adrenal tumor was incidentally detected in this patient. A diagnosis of adrenal Cushing's syndrome was based on the results of endocrinological and radiological examinations, although she showed none of the physical signs of Cushing's syndrome, glucose intolerance, hypertension or dyslipidermia. After a successful laparoscopic left adrenalectomy, the pathological diagnosis was adrenocortical adenoma. Slow tapering of glucocorticoids was needed to prevent adrenal insufficiency after surgery, and the plasma ACTH level remained high even though the serum cortisol level had reached the upper limit of the normal range. Further examination showed a urinary THF + allo-THF/THE ratio of 0.63, which was lower than that of control (0.90 +/- 0.13, mean +/- SD). Serum cortisol/cortisone ratios after the cortisone acetate administration were also decreased, and the serum half-life of cortisol was shorter than the normal range which has been reported. These findings indicated a partial defect in 11beta-hydroxysteroid dehydrogenase 1 (11beta-HSD1) activity, which converts cortisone to cortisol. Our case suggests that a change in 11beta-HSD1 activity results in inter-individual differences in glucocorticoid efficacy.
Endocrine Journal 06/2008; 55(4):709-15. · 2.03 Impact Factor
