Early induction of Hes1 by bone morphogenetic protein 9 plays a regulatory role in osteoblastic differentiation of a mesenchymal stem cell line.

Bone morphogenic protein 9 (BMP9) is one of the most potent inducers of osteogenic differentiation among the 14 BMP members, but its mechanism of action has not been fully demonstrated. Hes1 is a transcriptional regulator with basic helix-loop-helix (bHLH) domain and is a well-known Notch effector. In this study, we investigated the functional roles of early induction of Hes1 by BMP9 in a mouse mesenchymal stem cell line, ST2. Hes1 mRNA was transiently and periodically induced by BMP9 in ST2, which was inhibited by BMP signal inhibitors but not by Notch inhibitor. Interestingly, Hes1 knockdown in ST2 by siRNA increased the expression of osteogenic differentiation markers such as Sp7 and Ibsp and matrix mineralization in comparison with control siRNA transfected ST2. In contrast, forced expression of Hes1 by using the Tet-On system suppressed the expression of osteogenic markers and matrix mineralization by BMP9. We also found that the early induction of Hes1 by BMP9 suppressed the expression of Alk1, an essential receptor for BMP9. In conclusion, BMP9 rapidly induces the expression of Hes1 via the SMAD pathway in ST2 cells, which plays a negative regulatory role in osteogenic differentiation of mesenchymal stem cells induced by BMP9.

Comparison of the acid suppression effects between low-dose esomeprazole and famotidine in healthy subjects.

OBJECTIVE: Famotidine, an H2 receptor antagonist (H2RA), is mainly prescribed to alleviate the early symptoms of gastritis. Our aim was to explore the possibilities of low-dose esomeprazole as a treatment of gastritis as well as the pharmacodynamic (PD) properties of esomeprazole and famotidine. MATERIALS AND METHODS: A randomized, multiple-dose, 6-sequence, 3-period crossover study was conducted with a 7-day washout between periods. For each period, the subjects were administered one dose of esomeprazole 10 mg or famotidine 20 mg or esomeprazole 20 mg each day. To evaluate the PDs, the 24-hour gastric pH was recorded after single and multiple doses. The mean percentage of time during which the gastric pH was above 4 was evaluated for PD assessment. To confirm the pharmacokinetic (PK) characteristics of esomeprazole, blood was collected for up to 24 hours after multiple doses. RESULTS: 26 subjects completed the study. Following the multiple doses of esomeprazole 10 mg, esomeprazole 20 mg, and famotidine 20 mg, the mean percentages of time during which the gastric pH was above 4 over the course of 24 hour were 35.77 ± 19.56%, 53.75 ± 20.55%, and 24.48 ± 17.36%, respectively. After multiple doses, the time of peak plasma concentration at steady state (tmax,ss) was 1.00 and 1.25 hours for 10 and 20 mg of esomeprazole, respectively. The geometric mean ratio and its 90% confidence interval of area under the plasma drug concentration-time curve in steady state (AUCT,ss) and maximum concentration of drug in plasma in steady state (Cmax,ss) for esomeprazole 10 mg compared to 20 mg were 0.3654 (0.3381 - 0.3948) and 0.5066 (0.4601 - 0.5579), respectively. CONCLUSION: The PD parameters of esomeprazole 10 mg were comparable to those of famotidine after multiple doses. These findings provide support for further evaluating the use of 10 mg of esomeprazole as a treatment option for gastritis.

HIF-1α plays an essential role in BMP9-mediated osteoblast differentiation through the induction of a glycolytic enzyme, PDK1.

Bone homeostasis is regulated by bone morphogenic proteins (BMPs), among which BMP9 is one of the most osteogenic. Here, we have found that BMP9 rapidly increases the protein expression of hypoxia-inducible factor-1α (HIF-1α) in osteoblasts under normoxic conditions more efficiently than BMP2 or BMP4. A combination of BMP9 and hypoxia further increased HIF-1α protein expression. HIF-1α protein induction by BMP9 is not accompanied by messenger RNA (mRNA) increase and is inhibited by the activation of prolyl hydroxylase domain (PHD)-containing protein, indicating that BMP9 induces HIF-1α protein expression by inhibiting PHD-mediated protein degradation. BMP9-induced HIF-1α protein increase was abrogated by inhibitors of phosphoinositide 3-kinase (PI3K) and protein kinase B (AKT) kinase, indicating that it is mediated by PI3K-AKT signaling pathway. BMP9 increased mRNA expression of pyruvate dehydrogenase kinase 1 (PDK1), a glycolytic enzyme, and vascular endothelial growth factor-A (VEGF-A), an angiogenic factor, in osteoblasts. Notably, BMP9-induced mRNA expression of PDK1, but not that of VEGF-A, was significantly inhibited by small interference RNA-mediated knockdown of Hif-1α. BMP9-induced matrix mineralization and osteogenic marker gene expressions were significantly inhibited by chemical inhibition and gene knockdown of either Hif-1α or Pdk-1, respectively. Since increased glycolysis is an essential feature of differentiated osteoblasts, our findings indicate that HIF-1α expression is important in BMP9-mediated osteoblast differentiation through the induction of PDK1.

Lipoteichoic Acid and Lipopolysaccharides Are Affected by p38 and Inflammatory Markers and Modulate Their Promoting and Inhibitory Effects on Osteogenic Differentiation.

Lipoteichoic acid (LTA) and lipopolysaccharide (LPS) are cell wall components of Gram-positive and Gram-negative bacteria, respectively. Notably, oral microflora consists of a variety of bacterial species, and osteomyelitis of the jaw caused by dental infection presents with symptoms of bone resorption and osteosclerosis. However, the effects of LTA and LPS on osteogenic differentiation have not yet been clarified. We examined the effects of LTA and LPS on osteoblasts and found that LTA alone promoted alizarin red staining at low concentrations and inhibited it at high concentrations. Additionally, gene expression of osteogenic markers (ALP, OCN, and OPG) were enhanced at low concentrations of LTA. High concentrations of LPS suppressed calcification potential, and the addition of low concentrations of LTA inhibited calcification suppression, restoring the gene expression levels of suppressed bone differentiation markers (ALP, BSP, and OCN). Moreover, the suppression of p38, a signaling pathway associated with bone differentiation, had opposing effects on gene-level expression of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), suggesting that mixed LTA and LPS infections have opposite effects on bone differentiation through concentration gradients, involving inflammatory markers (TNF-α and IL-6) and the p38 pathway.

BMP9 directly induces rapid GSK3-ß phosphorylation in a Wnt-independent manner through class I PI3K-Akt axis in osteoblasts.

Bone morphogenetic protein (BMP)9 has been reported to be the most potent BMP to induce bone formation. However, the details of BMP9-transduced intracellular signaling remain ambiguous. Here, we have investigated signal transduction mechanisms of BMP9 in comparison to BMP2, another potent inducer of bone formation, in osteoblasts. In a mouse osteoblast cell line, BMP9 induced higher mRNA levels of alkaline phosphatase (ALP) and runt-related transcription factor 2 (Runx2) than BMP2 within 2 h. Unlike BMP2, BMP9 induced rapid phosphorylation of glycogen synthase kinase 3-ß (GSK3-ß) and protein kinase B (Akt) and increased the cellular protein content of ß-catenin. BMP9 moderately increased mRNA levels of several canonical Wingless-related integration site to lower degrees than BMP2. Furthermore, BMP9-induced GSK3-ß phosphorylation was not inhibited by pretreatment with actinomycin D, cycloheximide, or Brefeldin A, indicating it is independent of Wnt protein secretion. BMP9-induced GSK3-ß phosphorylation was abrogated by Akt or class I PI3K-specific inhibitors. Moreover, inactivation of GSK3-ß by LiCl did not further promote ALP and Runx2 mRNA induction by BMP9 as significantly as that by BMP2. Notably, BMP9-induced GSK3-ß phosphorylation was inhibited by small interfering RNA against endoglin and GIPC PDZ domain-containing family, member 1. Taken together, our present findings have indicated that BMP9 directly activates GSK3ß-ß-catenin signaling pathway through class I PI3K-Akt Axis in osteoblasts, which may be essential for the potent osteoinductive activity of BMP9.-Eiraku, N., Chiba, N., Nakamura, T., Amir, M. S., Seong, C.-H., Ohnishi, T., Kusuyama, J., Noguchi, K., Matsuguchi, T. BMP9 directly induces rapid GSK3-ß phosphorylation in a Wnt-independent manner through class I PI3K-Akt axis in osteoblasts.

Pharmacodynamics Between a Dual Delayed-Release Formulation of Low-Dose Esomeprazole and Famotidine in Healthy Korean Subjects.

PURPOSE: Gastritis, one of the most common clinically diagnosed conditions, is defined as the infiltration of inflammatory cells into the gastric mucosa. Drugs for gastritis include histamine-2 receptor antagonists and proton pump inhibitors (PPIs), which reduce acidity in the stomach, and antacids, which neutralize acid. Esomeprazole is a PPI for gastroesophageal reflux disease and gastric and duodenal ulcers that has been shown to be safe and effective at a 10 mg dose. Dual-release drugs have not yet been approved for the treatment of gastritis domestically or internationally. In this study, a dual delayed-release (DR) esomeprazole (10 mg), was compared to famotidine (20 mg) to determine its effectiveness in the treatment of gastritis. METHODS: This study was a randomized, open-label, multiple-dose, 2-treatment, 2-period, 2-sequence crossover study with a 7-day washout between periods. In each period, the subjects were administered one dose of esomeprazole (10 mg) or famotidine (20 mg) for 7 days at each period. The 24-hour gastric pH was recorded after single and multiple doses. The percentage of time (duration%) that the pH was maintained above 4 in the 24 hours after 7 days of repeated dosing was evaluated. FINDINGS: The mean percentages of time that the gastric pH was above 4 after multiple doses over 7 days of a dual DR esomeprazole (10 mg) and famotidine (20 mg) was 47.31% ± 14.85% and 23.88% ± 10.73%. IMPLICATIONS: Multiple doses of a dual DR esomeprazole (10 mg) showed effective gastric acid secretion suppression compared to famotidine with comparable safety and tolerability. These results provide evidence supporting the clinical use of a dual DR esomeprazole (10 mg) to treat gastritis. CLINICALTRIALS: gov identifier: NCT04967014.

The Association Among Post-hemodialysis Blood Pressure, Nocturnal Hypertension, and Cardiovascular Risk Factors.

Background: Most hemodialysis (HD) patients suffer from hypertension and have a heightened cardiovascular risk. While blood pressure (BP) control is essential to end-stage kidney disease (ESKD) patients, overly stringent control can lead to intradialytic hypotension (IDH). This study aimed to examine BP variations during and after HD to determine whether these variations correlate with IDH risk. Methods: BP measurements during dialysis were taken from 28 ESKD patients, and ambulatory BP monitoring was applied post-dialysis. Laboratory parameters and risk factors, including diabetes, coronary disease, and LV mass index, were compared between IDH and non-IDH groups using an independent t-test. Results: Of the 28 patients with an average age of 57.4 years, 16 (57.1%) had diabetes, 5 (17.9%) had coronary artery disease, and 1 (3.6%) had cerebrovascular disease. The mean systolic blood pressure (SBP) during and post-HD was 142.26 mmHg and 156.05 mmHg, respectively (p=0.0003). Similarly, the mean diastolic blood pressure (DBP) also demonstrated a significant increase, from 74.59 mmHg during HD to 86.82 mmHg post-HD (p<0.0001). Patients with IDH exhibited a more substantial SBP difference (delta SBP, 36.38 vs. 15.07 mmHg, p=0.0033; age-adjusted OR=1.58, p=0.0168) and a lower post-dialysis BUN level (12.75 vs. 18.77 mg/dL, p=0.0015; age-adjusted OR=0.76, p=0.0242). No significant variations were observed in daytime and nocturnal BP between the IDH and non-IDH groups. Conclusion: Hemodialysis patients exhibited a marked increase in post-dialysis BP and lacked a nocturnal BP dip, suggesting augmented cardiovascular risks. This highlights the importance of more stringent BP control after hemodialysis.

EGR1 plays an important role in BMP9-mediated osteoblast differentiation by promoting SMAD1/5 phosphorylation.

Bone morphogenetic proteins (BMPs) are essential regulators of skeletal homeostasis, and BMP9 is the most potently osteogenic among them. Here, we found that BMP9 and BMP2 rapidly induced early growth response 1 (EGR1) protein expression in osteoblasts through MEK/ERK pathway-dependent transcriptional activation. Knock-down of EGR1 using siRNA significantly inhibited BMP9-induced matrix mineralization and osteogenic marker gene expression in osteoblasts. Knock-down of EGR1 significantly reduced SMAD1/5 phosphorylation and inhibited the expression of their transcriptional targets in osteoblasts stimulated by BMP9. In contrast, forced EGR1 overexpression in osteoblasts enhanced BMP9-mediated osteoblast differentiation and SMAD1/5 phosphorylation. An intracellular association between EGR1 and SMAD1/5 was identified using immunoprecipitation assays. These results indicated that EGR1 plays an important role in BMP9-stimulated osteoblast differentiation by enhancing SMAD1/5 phosphorylation.

Bone morphogenetic protein 9 (BMP9) directly induces Notch effector molecule Hes1 through the SMAD signaling pathway in osteoblasts.

Bone morphogenetic protein (BMP) 9 is one of the most osteogenic BMPs, but its mechanism of action has not been fully elucidated. Hes1, a transcriptional regulator with a basic helix-loop-helix domain, is a well-known effector of Notch signaling. Here, we find that BMP9 induces periodic increases of Hes1 mRNA and protein expression in osteoblasts, presumably through an autocrine negative feedback mechanism. BMP9-mediated Hes1 induction is significantly inhibited by an ALK inhibitor and overexpression of Smad7, an inhibitory Smad. Luciferase and ChIP assays revealed that two Smad-binding sites in the 5' upstream region of the mouse Hes1 gene are essential for transcriptional activation by BMP9. Thus, our data indicate that BMP9 induces Hes1 expression in osteoblasts via the Smad signaling pathway.