Sclerostin is an osteocyte-derived inhibitor of osteoblast activity. The monoclonal antibody romosozumab binds to sclerostin and increases bone formation.
In a phase 2, multicenter, international, ...randomized, placebo-controlled, parallel-group, eight-group study, we evaluated the efficacy and safety of romosozumab over a 12-month period in 419 postmenopausal women, 55 to 85 years of age, who had low bone mineral density (a T score of -2.0 or less at the lumbar spine, total hip, or femoral neck and -3.5 or more at each of the three sites). Participants were randomly assigned to receive subcutaneous romosozumab monthly (at a dose of 70 mg, 140 mg, or 210 mg) or every 3 months (140 mg or 210 mg), subcutaneous placebo, or an open-label active comparator--oral alendronate (70 mg weekly) or subcutaneous teriparatide (20 μg daily). The primary end point was the percentage change from baseline in bone mineral density at the lumbar spine at 12 months. Secondary end points included percentage changes in bone mineral density at other sites and in markers of bone turnover.
All dose levels of romosozumab were associated with significant increases in bone mineral density at the lumbar spine, including an increase of 11.3% with the 210-mg monthly dose, as compared with a decrease of 0.1% with placebo and increases of 4.1% with alendronate and 7.1% with teriparatide. Romosozumab was also associated with large increases in bone mineral density at the total hip and femoral neck, as well as transitory increases in bone-formation markers and sustained decreases in a bone-resorption marker. Except for mild, generally nonrecurring injection-site reactions with romosozumab, adverse events were similar among groups.
In postmenopausal women with low bone mass, romosozumab was associated with increased bone mineral density and bone formation and with decreased bone resorption. (Funded by Amgen and UCB Pharma; ClinicalTrials.gov number, NCT00896532.).
Cystic Fibrosis (CF) exhibits morbidity in several organs, including progressive lung disease in all patients and intestinal obstruction at birth (meconium ileus) in ~15%. Individuals with the same ...causal CFTR mutations show variable disease presentation which is partly attributed to modifier genes. With >6,500 participants from the International CF Gene Modifier Consortium, genome-wide association investigation identified a new modifier locus for meconium ileus encompassing ATP12A on chromosome 13 (min p = 3.83x10(-10)); replicated loci encompassing SLC6A14 on chromosome X and SLC26A9 on chromosome 1, (min p<2.2x10(-16), 2.81x10(-11), respectively); and replicated a suggestive locus on chromosome 7 near PRSS1 (min p = 2.55x10(-7)). PRSS1 is exclusively expressed in the exocrine pancreas and was previously associated with non-CF pancreatitis with functional characterization demonstrating impact on PRSS1 gene expression. We thus asked whether the other meconium ileus modifier loci impact gene expression and in which organ. We developed and applied a colocalization framework called the Simple Sum (SS) that integrates regulatory and genetic association information, and also contrasts colocalization evidence across tissues or genes. The associated modifier loci colocalized with expression quantitative trait loci (eQTLs) for ATP12A (p = 3.35x10(-8)), SLC6A14 (p = 1.12x10(-10)) and SLC26A9 (p = 4.48x10(-5)) in the pancreas, even though meconium ileus manifests in the intestine. The meconium ileus susceptibility locus on chromosome X appeared shifted in location from a previously identified locus for CF lung disease severity. Using the SS we integrated the lung disease association locus with eQTLs from nasal epithelia of 63 CF participants and demonstrated evidence of colocalization with airway-specific regulation of SLC6A14 (p = 2.3x10(-4)). Cystic Fibrosis is realizing the promise of personalized medicine, and identification of the contributing organ and understanding of tissue specificity for a gene modifier is essential for the next phase of personalizing therapeutic strategies.
Phagocytic removal of apoptotic cells occurs efficiently in vivo such that even in tissues with significant apoptosis, very few apoptotic cells are detectable. This is thought to be due to the ...release of 'find-me' signals by apoptotic cells that recruit motile phagocytes such as monocytes, macrophages and dendritic cells, leading to the prompt clearance of the dying cells. However, the identity and in vivo relevance of such find-me signals are not well understood. Here, through several lines of evidence, we identify extracellular nucleotides as a critical apoptotic cell find-me signal. We demonstrate the caspase-dependent release of ATP and UTP (in equimolar quantities) during the early stages of apoptosis by primary thymocytes and cell lines. Purified nucleotides at these concentrations were sufficient to induce monocyte recruitment comparable to that of apoptotic cell supernatants. Enzymatic removal of ATP and UTP (by apyrase or the expression of ectopic CD39) abrogated the ability of apoptotic cell supernatants to recruit monocytes in vitro and in vivo. We then identified the ATP/UTP receptor P2Y2 as a critical sensor of nucleotides released by apoptotic cells using RNA interference-mediated depletion studies in monocytes, and macrophages from P2Y2-null mice. The relevance of nucleotides in apoptotic cell clearance in vivo was revealed by two approaches. First, in a murine air-pouch model, apoptotic cell supernatants induced a threefold greater recruitment of monocytes and macrophages than supernatants from healthy cells did; this recruitment was abolished by depletion of nucleotides and was significantly decreased in P2Y2-/- (also known as P2ry2-/-) mice. Second, clearance of apoptotic thymocytes was significantly impaired by either depletion of nucleotides or interference with P2Y receptor function (by pharmacological inhibition or in P2Y2-/- mice). These results identify nucleotides as a critical find-me cue released by apoptotic cells to promote P2Y2-dependent recruitment of phagocytes, and provide evidence for a clear relationship between a find-me signal and efficient corpse clearance in vivo.
Protein synthesis by the ribosome is highly dependent on the ionic conditions in the cellular environment, but the roles of ribosome solvation have remained poorly understood. Moreover, the functions ...of modifications to ribosomal RNA and ribosomal proteins have also been unclear. Here we present the structure of the Escherichia coli 70S ribosome at 2.4-Å resolution. The structure reveals details of the ribosomal subunit interface that are conserved in all domains of life, and it suggests how solvation contributes to ribosome integrity and function as well as how the conformation of ribosomal protein uS12 aids in mRNA decoding. This structure helps to explain the phylogenetic conservation of key elements of the ribosome, including post-transcriptional and post-translational modifications, and should serve as a basis for future antibiotic development.
Programmed cell death ligand 1 (PD-L1) is a molecule expressed on antigen-presenting cells that engages the PD-1 receptor on T cells and inhibits T-cell receptor signaling. The PD-1 axis can be ...exploited by tumor cells to dampen host antitumor immune responses and foster tumor cell survival. PD-1 blockade has shown promise in multiple malignancies but should be directed toward patients in whom it will be most effective. In recent studies, we found that the chromosome 9p24.1 amplification increased the gene dosage of PD-L1 and its induction by JAK2 in a subset of patients with classical Hodgkin lymphoma (cHL). However, cHLs with normal 9p24.1 copy numbers also expressed detectable PD-L1, prompting analyses of additional PD-L1 regulatory mechanisms.
Herein, we utilized immunohistochemical, genomic, and functional analyses to define alternative mechanisms of PD-L1 activation in cHL and additional EBV(+) lymphoproliferative disorders.
We identified an AP-1-responsive enhancer in the PD-L1 gene. In cHL Reed-Sternberg cells, which exhibit constitutive AP-1 activation, the PD-L1 enhancer binds AP-1 components and increases PD-L1 promoter activity. In addition, we defined Epstein-Barr virus (EBV) infection as an alternative mechanism for PD-L1 induction in cHLs with diploid 9p24.1. PD-L1 was also expressed by EBV-transformed lymphoblastoid cell lines as a result of latent membrane protein 1-mediated, JAK/STAT-dependent promoter and AP-1-associated enhancer activity. In addition, more than 70% of EBV(+) posttransplant lymphoproliferative disorders expressed detectable PD-L1.
AP-1 signaling and EBV infection represent alternative mechanisms of PD-L1 induction and extend the spectrum of tumors in which to consider PD-1 blockade.
Nonalcoholic fatty liver disease (NAFLD) is a spectrum comprised of isolated steatosis, nonalcoholic steatohepatitis (NASH), advanced fibrosis, and cirrhosis. The majority of NAFLD subjects do not ...have NASH and do not carry a significant risk for liver‐related adverse outcomes (cirrhosis and mortality). Globally, the prevalence of NAFLD is approximately 25%. In Asia, a gradient of high to low prevalence rates is noted from urban to rural areas. Given the prevalence of NAFLD, the clinical and economic burden of NAFLD and NASH can be substantial. With increasing recognition of NASH as an important liver disease, the diagnosis of NASH still requires a liver biopsy that is suboptimal. Although liver biopsy is the most accurate modality to diagnose and stage the severity of NASH, this method suffers from being invasive, costly, associated with potential complications, and plagued with interobserver variability of individual pathological features. A number of noninvasive modalities to diagnose NASH and stage liver fibrosis are being developed. These modalities include predictive models (NAFLD fibrosis score) and serum biomarkers such as enhanced liver fibrosis (ELF). Other tests are based on radiological techniques, such as transient elastography (TE) or magnetic resonance elastography (MRE), which are used to estimate liver stiffness as a potential surrogate of hepatic fibrosis. Although a dynamic field of research, most of these diagnostic modalities have area under the curve ranging between 0.76 and 0.90%, with MRE having the best predictive performance. In summary, developing safe and easily accessible noninvasive modalities to accurately diagnose and monitor NASH and associated fibrosis is of utmost importance in clinical practice and clinical research. These tests are not only important to risk stratify subjects at the greatest risk for progressive liver disease, but also to serve as appropriate surrogate endpoints for therapeutic clinical trials of NASH. (Hepatology 2018;68:349‐360).
Objective To determine if there is a relation between aspirin “resistance” and clinical outcomes in patients with cardiovascular disease.Design Systematic review and meta-analysis.Data source ...Electronic literature search without language restrictions of four databases and hand search of bibliographies for other relevant articles.Review methods Inclusion criteria included a test for platelet responsiveness and clinical outcomes. Aspirin resistance was assessed, using a variety of platelet function assays.Results 20 studies totalling 2930 patients with cardiovascular disease were identified. Most studies used aspirin regimens, ranging from 75-325 mg daily, and six studies included adjunct antiplatelet therapy. Compliance was confirmed directly in 14 studies and by telephone or interviews in three. Information was insufficient to assess compliance in three studies. Overall, 810 patients (28%) were classified as aspirin resistant. A cardiovascular related event occurred in 41% of patients (odds ratio 3.85, 95% confidence interval 3.08 to 4.80), death in 5.7% (5.99, 2.28 to 15.72), and an acute coronary syndrome in 39.4% (4.06, 2.96 to 5.56). Aspirin resistant patients did not benefit from other antiplatelet treatment.Conclusion Patients who are resistant to aspirin are at a greater risk of clinically important cardiovascular morbidity long term than patients who are sensitive to aspirin.
The most aggressive B cell lymphomas frequently manifest extranodal distribution and carry somatic mutations in the poorly characterized gene TBL1XR1. Here, we show that TBL1XR1 mutations skew the ...humoral immune response toward generating abnormal immature memory B cells (MB), while impairing plasma cell differentiation. At the molecular level, TBL1XR1 mutants co-opt SMRT/HDAC3 repressor complexes toward binding the MB cell transcription factor (TF) BACH2 at the expense of the germinal center (GC) TF BCL6, leading to pre-memory transcriptional reprogramming and cell-fate bias. Upon antigen recall, TBL1XR1 mutant MB cells fail to differentiate into plasma cells and instead preferentially reenter new GC reactions, providing evidence for a cyclic reentry lymphomagenesis mechanism. Ultimately, TBL1XR1 alterations lead to a striking extranodal immunoblastic lymphoma phenotype that mimics the human disease. Both human and murine lymphomas feature expanded MB-like cell populations, consistent with a MB-cell origin and delineating an unforeseen pathway for malignant transformation of the immune system.
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•TBL1XR1 mutation skews the humoral immune response toward producing memory B cells•TBL1XR1 mutant memory cells feature aberrant cyclic reentry to new germinal centers•Mutant TBL1XR1 acts by triggering aberrant targeting of SMRT complex to BACH2•TBL1XR1 mutation gives rise to extranodal ABC-DLBCLs derived from memory B cells
A subset of B cell lymphomas is driven by mutations that impair plasma cell differentiation and instead bias cell fate toward immature memory B cells, which preferentially re-enter germinal center reactions to drive lymphomagenesis.
Nonalcoholic fatty liver disease (NAFLD) and its progressive form non‐alcoholic steatohepatitis (NASH), are rapidly becoming among the top causes of cirrhosis, hepatocellular carcinoma, and ...indications for liver transplantation. Other than lifestyle modification through diet and exercise, there are currently no other approved treatments for NASH/NAFLD. Although weight loss can be effective, it is difficult to achieve and sustain. In contrast, bariatric surgery can improve metabolic conditions associated with NAFLD, and has been shown to improve liver histology. To have approved regimens for the treatment of NASH/NAFLD, several issues must be addressed. First, all stakeholders must agree on the most appropriate clinical trial endpoints for NASH. Currently, resolution of NASH (without worsening fibrosis) or reduction of fibrosis stage (without worsening NASH) are the accepted endpoints by the regulatory authorities. It is important to recognize the prognostic implication of histologic features of NASH. In this context, although histologic NASH has been associated with advanced fibrosis, it is not an independent predictor of long‐term mortality. In contrast, there are significant data to suggest that fibrosis stage is the only robust and independent predictor of liver‐related mortality. In addition to the primary endpoints, several important secondary endpoints, including noninvasive biomarkers, long‐term outcomes, and patient‐reported outcomes must be considered. In 2018, a few phase 3 clinical trials for the treatment of NASH have been initiated. Additionally, a number of phase 2a and 2b clinical trials targeting different pathogenic pathways in NASH are in the pipeline of emerging therapies. Conclusion: Over the next 5 years, some of these regimens are expected to provide potential new treatment options for patients with NASH/NAFLD. (Hepatology 2018;68:361‐371)
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