A RUNX2 stabilization pathway mediates physiologic and pathologic bone formation

The osteoblast differentiation capacity of skeletal stem cells (SSCs) must be tightly regulated, as inadequate bone formation results in low bone mass and skeletal fragility, and over-exuberant osteogenesis results in heterotopic ossification (HO) of soft tissues. RUNX2 is essential for tuning this balance, but the mechanisms of posttranslational control of RUNX2 remain to be fully elucidated. Here, we identify that a CK2/HAUSP pathway is a key regulator of RUNX2 stability, as Casein kinase 2 (CK2) phosphorylates RUNX2, recruiting the deubiquitinase herpesvirus-associated ubiquitin-specific protease (HAUSP), which stabilizes RUNX2 by diverting it away from ubiquitin-dependent proteasomal degradation. This pathway is important for both the commitment of SSCs to osteoprogenitors and their subsequent maturation. This CK2/HAUSP/RUNX2 pathway is also necessary for HO, as its inhibition blocked HO in multiple models. Collectively, active deubiquitination of RUNX2 is required for bone formation and this CK2/HAUSP deubiquitination pathway offers therapeutic opportunities for disorders of inappropriate mineralization

The ERK MAPK Pathway Is Essential for Skeletal Development and Homeostasis

Mitogen-activated protein kinases (MAPKs) are a family of protein kinases that function as key signal transducers of a wide spectrum of extracellular stimuli, including growth factors and pro-inflammatory cytokines. Dysregulation of the extracellular signal-regulated kinase (ERK) MAPK pathway is associated with human skeletal abnormalities including Noonan syndrome, neurofibromatosis type 1, and cardiofaciocutaneous syndrome. Here, we demonstrate that ERK activation in osteoprogenitors is required for bone formation during skeletal development and homeostasis. Deletion of Mek1 and Mek2, kinases upstream of ERK MAPK, in osteoprogenitors (Mek1(Osx)Mek2(-/-)), resulted in severe osteopenia and cleidocranial dysplasia (CCD), similar to that seen in humans and mice with impaired RUNX2 function. Additionally, tamoxifen-induced deletion of Mek1 and Mek2 in osteoprogenitors in adult mice (Mek1(Osx-ERT)Mek2(-/-)) significantly reduced bone mass. Mechanistically, this corresponded to decreased activation of osteoblast master regulators, including RUNX2, ATF4, and beta-catenin. Finally, we identified potential regulators of osteoblast differentiation in the ERK MAPK pathway using unbiased phospho-mass spectrometry. These observations demonstrate essential roles of ERK activation in osteogenesis and bone formation

Bone-targeting AAV-mediated silencing of Schnurri-3 prevents bone loss in osteoporosis

RNAi-based bone anabolic gene therapy has demonstrated initial success, but many practical challenges are still unmet. Here, we demonstrate that a recombinant adeno-associated virus 9 (rAAV9) is highly effective for transducing osteoblast lineage cells in the bone. The adaptor protein Schnurri-3 (SHN3) is a promising therapeutic target for osteoporosis, as deletion of shn3 prevents bone loss in osteoporotic mice and short-term inhibition of shn3 in adult mice increases bone mass. Accordingly, systemic and direct joint administration of an rAAV9 vector carrying an artificial-microRNA that targets shn3 (rAAV9-amiR-shn3) in mice markedly enhanced bone formation via augmented osteoblast activity. Additionally, systemic delivery of rAAV9-amiR-shn3 in osteoporotic mice counteracted bone loss and enhanced bone mechanical properties. Finally, we rationally designed a capsid that exhibits improved specificity to bone by grafting the bone-targeting peptide motif (AspSerSer)6 onto the AAV9-VP2 capsid protein. Collectively, our results identify a bone-targeting rAAV-mediated gene therapy for osteoporosis

Combined spinal-epidural anesthesia for cesarean section in a patient with Moyamoya disease -A case report-

Moyamoya disease is a rare progressive occlusive disease of the internal carotid arteries. We report a case of combined spinal-epidural anesthesia in a patient with Moyamoya disease presenting for Cesarean section. Hypotension associated with spinal anesthesia for Cesarean section is the most common and serious adverse effect despite the use of uterine displacement and volume preload. We continuously infused phenylephrine and ephedrine to prevent hypotension. The intraoperative hemodynamic state was stable. The patient had no significant postoperative complications

Stereotactic body radiation therapy for elderly patients with small hepatocellular carcinoma: a retrospective observational study

Background/Aim We aimed to investigate the efficacy and safety of stereotactic body radiation therapy (SBRT) in elderly patients with small hepatocellular carcinomas (HCC). Methods Eighty-three patients (89 lesions) with HCC who underwent SBRT between January 2012 and December 2018 were reviewed in this retrospective observational study. The key inclusion criteria were as follows: 1) age ≥75 years, 2) contraindications for hepatic resection or percutaneous ablative therapies, 3) no macroscopic vascular invasion, and 4) no extrahepatic metastasis. Results The patients were 75-90 years of age, and 49 (59.0%) of them were male. Most patients (94.0%) had an Eastern Cooperative Oncology Group performance status of 0 or 1. Seventy-four patients (89.2%) had Child-Pugh class A hepatic function before SBRT. The median tumor size was 1.6 cm (range, 0.7-3.5). The overall median follow-up period was 34.8 months (range, 7.3-99.3). The 5-year local tumor control rate was 90.1%. The 3-year and 5-year overall survival rate was 57.1% and 40.7%, respectively. Acute toxicity grade ≥3 was observed in three patients (3.6%) with elevated serum hepatic enzymes; however, no patient experienced a worsening of the Child-Pugh score to ≥2 after SBRT. None of the patients developed late toxicity (grade ≥3). Conclusions SBRT is a safe treatment option with a high local control rate in elderly patients with small HCC who are not eligible for other curative treatments

Subclassification of advanced-stage hepatocellular carcinoma with macrovascular invasion: combined transarterial chemoembolization and radiotherapy as an alternative first-line treatment

Background/Aim The Barcelona Clinic Liver Cancer (BCLC) guidelines recommend systemic therapy as the only first-line treatment for patients with BCLC stage C hepatocellular carcinoma (HCC) despite its heterogeneity of disease extent. We aimed to identify patients who might benefit from combined transarterial chemoembolization (TACE) and radiation therapy (RT) by subclassifying BCLC stage C. Methods A total of 1,419 treatment-naïve BCLC stage C patients with macrovascular invasion (MVI) who were treated with combined TACE and RT (n=1,115) or systemic treatment (n=304) were analyzed. The primary outcome was overall survival (OS). Factors associated with OS were identified and assigned points by the Cox model. The patients were subclassified into three groups based on these points. Results The mean age was 55.4 years, and 87.8% were male. The median OS was 8.3 months. Multivariate analysis revealed a significant association of Child-Pugh B, infiltrative-type tumor or tumor size ≥10 cm, main or bilateral portal vein invasion, and extrahepatic metastasis with poor OS. The sub-classification was categorized into low (point ≤1), intermediate (point=2), and high (point ≥3) risks based on the sum of points (range, 0–4). The OS in the low, intermediate, and high-risk groups was 22.6, 8.2, and 3.8 months, respectively. In the low and intermediate-risk groups, patients treated with combined TACE and RT exhibited significantly longer OS (24.2 and 9.5 months, respectively) than those who received systemic treatment (6.4 and 5.1 months, respectively; P<0.0001). Conclusions Combined TACE and RT may be considered as a first-line treatment option for HCC patients with MVI when classified into low- and intermediate-risk groups