Effect of Different Concentrations of Astragali Radix Containing Serum on CYP24A1，CYP27B1 mRNA and Protein in Osteogenic Differentiation of Aging Bone Marrow Mesenchymal Stem Cells / 中国实验方剂学杂志

Objective:To investigate the effects of different concentrations of Astragali Radix containing serum on the expression of 24-hydroxylase（CYP24A1），1α-OHase（CYP27B1） mRNA and protein in rat bone marrow mesenchymal stem cells （BMSCs）， and to explore the mechanism of primary osteoporosis （OP）. Method:The experiment was divided into 6 groups，like normal group， model group， low ，middle and high dose group of Astragali Radix containing serum（20%，40%，60%），Vitamin D group. Cell proliferation toxicity assay（CCK-8） was used to detect the effect of different concentrations of Astragali Radix containing serum on survival rate of aging BMSCs.Real-time quantitative PCR（Real-time PCR） and Western blot was used to detect the expression of CYP24A1 CYP27B1 mRNA and protein in senile BMSCs osteogenic differentiation cells by different concentrations of Astragali Radix containing serum. Result:Compared with normal group， the proliferation and survival rate of BMSCs osteoblasts induced by D-galactose in model group was significantly lower than that in normal group （P<0.01）. Compared with model group， medium and high dose groups and Vitamin D group could improve the proliferation and differentiation of aging BMSCs into osteoblasts in different degrees（P<0.01）. The relative expression of CYP27B1 mRNA and protein in model group was significantly lower than that in normal group， while the relative expression of CYP24A1 mRNA and protein in model group was significantly higher than that in normal group. Compared with model group， high dose Astragali Radix containing serum group could increase the relative expression of CYP27B1 mRNA and protein， and decrease the relative expression of CYP24A1 mRNA and protein in a dose-dependent manner（P<0.01）. Conclusion:The mechanism of different concentrations of Astragali Radix containing serum in the treatment of osteoporosis may be related to the regulation of CYP24A1， CYP27B1 mRNA and protein in the osteogenic differentiation of aging BMSCs.

Vitamin D Dependent Rickets Type 1A Caused by CYP27B1 Mutation

Vitamin D dependent rickets type 1A (VDDR1A) is an autosomal recessive disorder caused by mutations in CYP27B1 . Clinical findings are growth retardation, hypotonia, muscle weakness, hypocalcemic seizures, and radiological features of rickets. We aimed to present the VDDR1A case with a genetic study of CYP27B1 . The 14-month-old boy was admitted to the hospital due to a seizure. Serum calcium, phosphorus, alkaline phosphatase, parathyroid hormone (PTH), 25(OH) vitamin D, and 1,25(OH)2 vitamin D values were 5.1 mg/dL, 3.7 mg/dL, 705 IU/L, 429 pg/mL, 24.9 ng/mL, and 8.8 pg/mL, respectively. Radiological study showed cupping and fraying of the distal ulna and radius. The molecular genetic study revealed that the patient had a compound heterozygous mutation, Phe443Profs*24 and c.589+1G>A, in CYP27B1 . Genetic analysis of the family members presented that the mother was heterozygous for the mutation c.589+1G>A, and that the father was heterozygous for Phe443Profs*24. The patient was treated with calcium lactate and calcitriol. Until now, six Korean patients with VDDR1A have been studied. Including this case, Korean patients with VDDR1A were found to have only three different mutations in 14 alleles, indicating that the mutation in the CYP27B1 gene is homogeneous in the Korean population.

A case of vitamin D hydroxylation-deficient rickets type 1A caused by 2 novel pathogenic variants in CYP27B1 gene

Vitamin D hydroxylation-deficient rickets type 1A (VDDR1A, OMIM 264700) is a rare autosomal recessive inherited disorder. Pathogenic variants in the CYP27B1 gene lead to loss of 1α-hydroxylase activity. We report the case of a 22-month-old toddler who presented with growth retardation and delayed development. The patient exhibited the typical laboratory findings of VDDR1A, including hypocalcemia (calcium: 5.2 mg/dL), elevated serum level of alkaline phosphatase (2,600 U/L), elevated serum level of intact-parathyroid hormone (238 pg/mL), low 1,25(OH)₂D₃ level (11.2 pg/mL), and normal 25(OH)D₃ level (40.7 ng/mL). His height and weight were 76.5 cm and 9.5 kg, respectively (both <3rd percentile). The Bayley Scales of Infant and Toddler Development II indicated significantly delayed development (mental development index <50, psychomotor development index <50). The patient was a compound heterozygous for two novel pathogenic variants in the CYP27B1 gene: c.57_69del (p.Glu20Profs*2) and c.171dupG (p.Leu58Alafs*275), inherited from his mother and father, respectively. The patient showed remarkable improvement after treatment with calcitriol and calcium carbonate.

The role of inadequate vitamin D receptor activation and CYP27B1 metabolic modulation in the cardiorenal syndrome / 天津医药

@#In recent years, it has been found that the lack of vitamin D receptor (VDR) activation is closely associated with the development of cardiorenal syndrome (CRS). Hydroxylation catalyzed by renal 25-hydroxyvitamin D-1α hydroxylase (CYP27B1) is responsible for over 90% circulating concentrations of vitamin D activation, which then exerts biologic actions of vitamin D. Loss of renal CYP27B1 during CRS is associated with gradual decline in circulating 1,25(OH)2D3, resulting in inadequate VDR activation in renal and cardiac tissues, thereby promoting renal and cardiac damages. Therefore, CYP27B1 and VDR may become key targets for the combination of chronic kidney disease and cardiovascular disease. In this paper, the roles of vitamin D/VDR and metabolic regulation of CYP27B1 in CRS are reviewed, which may also provide new therapeutic strategies for CRS.

Long-term clinical outcome and the identification of homozygous CYP27B1 gene mutations in a patient with vitamin D hydroxylation-deficient rickets type 1A

Vitamin D hydroxylation-deficient rickets type 1A (VDDR1A) is an autosomal recessively-inherited disorder caused by mutations in CYP27B1 encoding the 1α-hydroxylase enzyme. We report on a female patient with VDDR1A who presented with hypocalcemic seizure at the age of 13 months. The typical clinical and biochemical features of VDDR1A were found, such as hypocalcemia, increased alkaline phosphatase, secondary hyperparathyroidism and normal 25-hydroxyvitamin D3 (25(OH)D₃). Radiographic images of the wrist showed metaphyseal widening with cupping and fraying of the ulna and distal radius, suggesting rickets. A mutation analysis of the CYP27B1 gene identified a homozygous mutation of c.589+1G>A in the splice donor site in intron 3, which was known to be pathogenic. Since that time, the patient has been under calcitriol and calcium treatment, with normal growth and development. During the follow-up period, she did not develop genu valgum, scoliosis, or nephrocalcinosis.