Evidence of causality of low body mass index on risk of adolescent idiopathic scoliosis: a Mendelian randomization study

IntroductionAdolescent idiopathic scoliosis (AIS) is a disorder with a three-dimensional spinal deformity and is a common disease affecting 1-5% of adolescents. AIS is also known as a complex disease involved in environmental and genetic factors. A relation between AIS and body mass index (BMI) has been epidemiologically and genetically suggested. However, the causal relationship between AIS and BMI remains to be elucidated.Material and methodsMendelian randomization (MR) analysis was performed using summary statistics from genome-wide association studies (GWASs) of AIS (Japanese cohort, 5,327 cases, 73,884 controls; US cohort: 1,468 cases, 20,158 controls) and BMI (Biobank Japan: 173430 individual; meta-analysis of genetic investigation of anthropometric traits and UK Biobank: 806334 individuals; European Children cohort: 39620 individuals; Population Architecture using Genomics and Epidemiology: 49335 individuals). In MR analyses evaluating the effect of BMI on AIS, the association between BMI and AIS summary statistics was evaluated using the inverse-variance weighted (IVW) method, weighted median method, and Egger regression (MR-Egger) methods in Japanese.ResultsSignificant causality of genetically decreased BMI on risk of AIS was estimated: IVW method (Estimate (beta) [SE] = -0.56 [0.16], p = 1.8 × 10-3), weighted median method (beta = -0.56 [0.18], p = 8.5 × 10-3) and MR-Egger method (beta = -1.50 [0.43], p = 4.7 × 10-3), respectively. Consistent results were also observed when using the US AIS summary statistic in three MR methods; however, no significant causality was observed when evaluating the effect of AIS on BMI.ConclusionsOur Mendelian randomization analysis using large studies of AIS and GWAS for BMI summary statistics revealed that genetic variants contributing to low BMI have a causal effect on the onset of AIS. This result was consistent with those of epidemiological studies and would contribute to the early detection of AIS

Treatment of In-Stent Restenosis by Excimer Laser Coronary Atherectomy and Drug-Coated Balloon: Serial Assessment with Optical Coherence Tomography

Objectives. We aimed to compare the results of neointimal modification before drug-coated balloon (DCB) treatment with excimer laser coronary atherectomy (ELCA) plus scoring balloon predilation versus scoring balloon alone in patients presenting with in-stent restenosis (ISR). Background. Treatment of ISR with ELCA typically results in superior acute gain by neointima debulking. However, the efficacy of combination therapy of ELCA and DCB remains unknown. Methods. A total of 42 patients (44 ISR lesions) undergoing DCB treatment with ELCA plus scoring balloon (ELCA group, n = 18) or scoring balloon alone (non-ELCA group, n = 24) were evaluated via serial assessment by optical coherence tomography (OCT) performed before, after intervention, and at 6 months. Results. Although there was significantly greater frequency of diffuse restenosis and percent diameter stenosis (%DS) after intervention in the ELCA group, comparable result was shown in %DS, late lumen loss, and binary angiographic restenosis at follow-up. On OCT analysis, a decreased tendency in the minimum lumen area and a significant decrease in the minimum stent area were observed in the ELCA group between 6-month follow-up and after intervention (-0.89 ± 1.36 mm2 vs. -0.09 ± 1.25 mm2, p = 0.05, -0.49 ± 1.48 mm2 vs. 0.28 ± 0.78 mm2, p = 0.03, respectively). The changes in the neointimal area were similar between the groups, and target lesion revascularization showed comparable rates at 1 year (11.1% vs. 11.4%, p = 0.85). Conclusions. Despite greater %DS after intervention, ELCA before DCB had possible benefit for late angiographic and clinical outcome

Mammalian Formin Fhod3 Regulates Actin Assembly and Sarcomere Organization in Striated Muscles*

Actin filament assembly in nonmuscle cells is regulated by the actin polymerization machinery, including the Arp2/3 complex and formins. However, little is known about the regulation of actin assembly in muscle cells, where straight actin filaments are organized into the contractile unit sarcomere. Here, we show that Fhod3, a myocardial formin that localizes to thin actin filaments in a striated pattern, regulates sarcomere organization in cardiomyocytes. RNA interference-mediated depletion of Fhod3 results in a marked reduction in filamentous actin and disruption of the sarcomeric structure. These defects are rescued by expression of wild-type Fhod3 but not by that of mutant proteins carrying amino acid substitution for conserved residues for actin assembly. These findings suggest that actin dynamics regulated by Fhod3 are critical for sarcomere organization in striated muscle cells

The mammalian formin FHOD1 is activated through phosphorylation by ROCK and mediates thrombin-induced stress fibre formation in endothelial cells

Formin-family proteins, in the active state, form actin-based structures such as stress fibres. Their activation mechanisms, however, are largely unknown except that mDia and its closely related formins can be activated by direct binding of the small GTPase Rho or Cdc42. Here we show that the Rho-dependent protein kinase ROCK phosphorylates the C-terminal residues Ser1131, Ser1137, and Thr1141 of formin homology domain protein 1 (FHOD1), a major endothelial formin that is normally autoinhibited by intramolecular interaction between the N- and C-terminal regions. Phosphorylation of FHOD1 at the three residues fully disrupts the autoinhibitory interaction, which culminates in formation of stress fibres. We also demonstrate that, in vascular endothelial cells, thrombin, a vasoactive substance leading to Rho activation, elicits both FHOD1 phosphorylation and stress fibre formation in a ROCK-dependent manner, and that FHOD1 depletion by RNA interference impairs thrombin-induced stress fibre formation. Based on these findings we propose a novel mechanism for activation of formin-family proteins: ROCK, activated by G protein-coupled receptor ligands such as thrombin, directly phosphorylates FHOD1 at the C-terminal region, which renders this formin in the active form, leading to stress fibre formation