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ObjectivesTeriparatide (TPTD) is an effective treatment for osteoporosis but the individual response to therapy is variable for reasons that are unclear. This study aimed to determine whether the response to TPTD might be influenced by genetic factors.MethodsWe searched for predictors of the response of bone mineral density (BMD) to TPTD using a two-stage genome-wide association study in 437 patients with osteoporosis from three referral centres. Demographic and clinical data including the response of BMD to treatment at the lumbar spine and hip were extracted from the medical records of each participant.ResultsAllelic variation at rs6430612 on chromosome 2, closeto the CXCR4gene was associated with the response of spine BMD to TPTD at a genome wide significant level (p=9.2×10−9beta=−0.35 (−0.47 to −0.23)). The increase in BMD was almost twice as great in AA homozygotes at rs6430612 as compared with GG homozygotes with intermediate values in heterozygotes. The same variant was also associated with response of femoral neck and total hip BMD (p=0.007). An additional locus on chromosome 19 tagged by rs73056959 was associated with the response of femoral neck BMD to TPTD (p=3.5×10−9, beta=−1.61 (−2.14 to −1.07)).ConclusionsGenetic factors influence the response to TPTD at the lumbar spine and hip with a magnitude of effect that is clinically relevant. Further studies are required to identify the causal genetic variants and underlying mechanisms as well as to explore how genetic testing for these variants might be implemented in clinical practice.

De novo variants affecting the core complex required for monoubiquitination of histone H2B (H2Bub1) are enriched in human congenital heart disease. H2Bub1 is an enigmatic chromatin modification required in stem cell differentiation, cilia function, post-natal cardiomyocyte maturation and transcriptional elongation. However, it is still unknown how H2Bub1 affects cardiogenesis (heart structure formation), which is distinct from cardiomyocyte maturation and underlies congenital heart disease. Here we show that the RNF20-core complex (RNF20-RNF40-UBE2B) is required for cardiogenesis in mouse embryos and is essential for differentiation of human iPSCs into cardiomyocytes. Mice with cardiac-specific deletion of Rnf20 are e12.5 lethal, have thinned myocardium, a deficient ventricular septum, and abnormal cardiac sarcomere organization. We analyzed H2Bub1 marks during the time course of differentiation of human iPSCs into cardiomyocytes, and demonstrated that H2Bub1 marks are erased from a majority of genes at the transition from cardiac mesoderm to cardiac progenitor cells, but are preserved on a subset of long cardiac-specific genes. Sarcomeric gene expression is dependent on normal H2Bub1 both in mice and in human iPSC-derived cardiomyocytes. Finally, we identify an accumulation of H2Bub1 near the center of tissue-specific genes in human cardiomyocytes, mouse embryonic fibroblasts, and human fetal osteoblasts associated with transcriptional elongation efficiency that is absent in UBE2B knock-out H2Bub1-deficient cardiomyocytes. In summary, normal H2Bub1 distribution is required for cardiac morphogenesis and cardiomyocyte differentiation, and we propose that H2Bub1 regulates tissue-specific gene expression by increasing the efficiency of transcriptional elongation.

Although cardiac abnormalities have been observed in a growing class of human disorders caused by defective primary cilia, the function of cilia in the heart remains an underexplored area. The primary function of cilia in the heart was long thought to be restricted to left-right axis patterning during embryogenesis. However, new findings have revealed broad roles for cilia in congenital heart disease, valvulogenesis, myocardial fibrosis and regeneration, and mechanosensation. In this Review, we describe advances in our understanding of the mechanisms by which cilia function contributes to cardiac left-right axis development and discuss the latest findings that highlight a broader role for cilia in cardiac development. Specifically, we examine the growing line of evidence connecting cilia function to the pathogenesis of congenital heart disease. Furthermore, we also highlight research from the past 10 years demonstrating the role of cilia function in common cardiac valve disorders, including mitral valve prolapse and aortic valve disease, and describe findings that implicate cardiac cilia in mechanosensation potentially linking haemodynamic and contractile forces with genetic regulation of cardiac development and function. Finally, given the presence of cilia on cardiac fibroblasts, we also explore the potential role of cilia in fibrotic growth and summarize the evidence implicating cardiac cilia in heart regeneration.

De-novo mutations affecting Histone2B-K120 monoubiquitination (H2Bub1) are enriched in congenital heart disease; however, how H2Bub1 affects heart development beyond its function in establishing left-right asymmetry remains unknown. Here we show that the RNF20-core complex (RNF20-RNF40-UBE2B), which catalyzes H2Bub1, is required for cardiac development in-vivo in mice and in-vitro in iPSC-derived cardiomyocytes. Mice with cardiac-specific deletion of Rnf20 have abnormal myocardium and ventricular septal defects; iPSCs with mutations affecting H2Bub1 cannot efficiently differentiate into cardiomyocytes. Sarcomeric gene expression is dependent on normal H2Bub1 both in mice and in iPSC-derived cardiomyocytes. Finally, we identify an accumulation of H2Bub1 near the center of tissue-specific genes in cardiomyocytes and MEFs associated with transcriptional efficiency that is reduced in UBE2B-/- cardiomyocytes. In summary, normal H2Bub1 distribution is required in cardiac development, and H2Bub1 accumulation acts as a general mechanism for tissue-specific regulation of transcriptional elongation efficiency.

Background/Aims Patients with rheumatoid arthritis (RA) are at increased risk of developing osteoporosis (OP) and have a twofold increased risk of vertebral fracture compared with the general population. There is increasing evidence that teriparatide (TPTD) is superior to anti-resorptive medication in patients with severe spinal OP.The aim of this study was to compare the efficacy of TPTD with anti-resorptive treatment (ART) in RA patients with severe spinal OP. Methods Observational study of RA patients and controls with severe OP who were referred to a specialist osteoporosis clinic. Patients with a history of two vertebral fractures or a spinal BMD Tscore < -4 were offered either TPTD or standard care with either oral or parenteral ART. After completion of TPTD treatment patients were advised to commence ART. DEXA re-evaluation was usually performed after 1, 2 and 5 years. Results We studied 59 postmenopausal women with RA who had severe spinal OP. In the RA group 29 patients received TPTD treatment and 30 patients were started on ART (12 Zoledronic acid, 11 Alendronate, 3 Risedronate, 2 Denosumab, 1 Etidronate and 1 unknown).RA patients who were started on TPTD were on average 5 years younger (65.4 ±10.6) than patients who were started on ART (70.6±8.2; p = 0.041). Slightly more than half of TPTD RA patients (55.2%) had previously received bisphosphonates and 10.3% received low dose Prednisolone (mean± SD dose = 5.5 ± 3.3 mg). Baseline lumbar spine T-score was -4.25±0.57 in the RA TPTD group. Patients with RA who elected to have ART as opposed to TPTD had higher BMD values as compared with those who chose to have TPTD (T-score = -3.39±1.09; p = 0.001, from RA TPTD group).We found that increase in BMD with TPTD treatment was superior to ART in the RA group at increasing spine BMD after 2 years (+17.59% ± 9.63% vs 3.19 % ± 4.99% , p value Conclusion This real-world study confirms that TPTD treatment is more effective in treating severe spinal OP in RA patients than antiresorptive medication alone. Despite the fact that the majority of RA patients had been pre-treated with bisphosphonates the TPTD treatment effect in RA patients was robust. Anabolic treatment with TPTD is a good option for RA patients with severe spinal OP. Disclosure B. Hauser: Other; Dr Hauser has received fees for a promotional article from Gedeon Richter. K.M. Berg: None. J.A. Lambert: None. S.H. Ralston: Grants/research support; Prof Ralston has received grant funding from Lilly for an observational study and donation of Teriparatide for the TOPAZ trial in Osteogenesis Imperfecta.

Hypophosphatasia (HPP) is a rare inherited disorder characterized by rickets and low circulating concentrations of total alkaline phosphatase (ALP) caused by mutations in ALPL. Severe HPP presents in childhood but milder forms can present in adulthood. The prevalence and clinical features of adult HPP are poorly defined. The aim of this study was to evaluate the prevalence and clinical significance of low serum total alkaline phosphatase (ALP) levels in a clinic-based population of adult osteoporotic patients. We searched for patients with low ALP in a cohort of 3285 patients referred to an osteoporosis clinic over a 10-year period and performed mutation screening of ALPL in those with low ALP (≤40 U/L) on two or more occasions. These individuals were matched with four clinic controls with a normal ALP. We also evaluated the prevalence of low ALP and ALPL mutations in 639 individuals from the general population from the same region. We identified 16/3285 (0.49%) clinic patients with low ALP and 14 (87.5%) had potentially pathogenic variants in ALPL. Eight of these individuals were heterozygous for mutations previously described in HPP and 2 were heterozygous for novel mutations (p.Arg301Trp and p.Tyr101X). These mutations were not found in clinic controls or in the general population. Eight patients with low ALP, including 4 with ALPL mutations, were treated with bisphosphonates for an average of 6.5 years. In these individuals, the rate of fractures during treatment was comparable to that in normal ALP clinic controls who were treated with bisphosphonates. We conclude that heterozygous loss-of-function mutations in ALPL are common in osteoporosis patients with low ALP. Further studies are required to determine how best these individuals should be treated. © 2019 The Authors. Journal of Bone and Mineral Research published by American Society for Bone and Mineral Research.

Teriparatide (TPTD) is the most widely used anabolic agent in the treatment of patients with osteoporosis although its use is restricted in many countries. A recent randomised trial confirmed that TPTD was superior to risedronate at preventing vertebral fractures over a 2-year period. There is limited information on the relative effectiveness of TPTD compared with standard care in routine clinical practice. In this paper, we report the results of an extended observational study of 724 women referred to a specialist clinic with severe osteoporosis over an 11.5-year period, who were considered for TPTD therapy. Of these patients, 496 (68.5%) were treated with TPTD, whereas the remaining 228 (31.5%) received other treatments. This was either because they were unwilling or unable to self-inject (52.6%), because they had already been established on oral bisphosphonates (31.1%) or because of contraindications (12.7%). The TPTD group were younger than the standard care group (69.6 vs. 74.1 years) and had a lower 10-year fracture risk (25.7% vs. 28.6%). Those treated with TPTD had a greater increase in BMD at the lumbar spine compared with standard care (13.3% vs. 8.2%, p

Hundreds of long non-coding RNAs (lncRNAs) have been identified as potential regulators of gene expression, but their functions remain largely unknown. To study the role of lncRNAs during vertebrate development, we selected 25 zebrafish lncRNAs based on their conservation, expression profile or proximity to developmental regulators, and used CRISPR-Cas9 to generate 32 deletion alleles. We observed altered transcription of neighboring genes in some mutants, but none of the lncRNAs were required for embryogenesis, viability or fertility. Even RNAs with previously proposed non-coding functions (cyrano and squint) and other conserved lncRNAs (gas5 and lnc-setd1ba) were dispensable. In one case (lnc-phox2bb), absence of putative DNA regulatory-elements, but not of the lncRNA transcript itself, resulted in abnormal development. LncRNAs might have redundant, subtle, or context-dependent roles, but extrapolation from our results suggests that the majority of individual zebrafish lncRNAs have no overt roles in embryogenesis, viability and fertility.

Hundreds of long non-coding RNAs (lncRNAs) have been identified as potential regulators of gene expression, but their functions remain largely unknown. To study the role of lncRNAs during vertebrate development, we selected 25 zebrafish lncRNAs based on their conservation, expression profile or proximity to developmental regulators, and used CRISPR-Cas9 to generate 32 deletion alleles. We observed altered transcription of neighboring genes in some mutants, but none of the lncRNAs were required for embryogenesis, viability or fertility. Even RNAs with previously proposed non-coding functions (cyranoandsquint) and other conserved lncRNAs (gas5andlnc-setd1ba)were dispensable. In one case (lnc-phox2bb), absence of putative DNA regulatory-elements, but not of the lncRNA transcript itself, resulted in abnormal development. LncRNAs might have redundant, subtle, or context-dependent roles, but extrapolation from our results suggests that the majority of individual zebrafish lncRNAs are dispensable for embryogenesis, viability and fertility.