Using Functional Genomic Data in Monocytes/Macrophages and Genotyping to Nominate Disease-Driving Single Nucleotide Polymorphisms and Target Genes in Juvenile Idiopathic Arthritis.

Introduction: GWAS have identified multiple regions that confer risk for juvenile idiopathic arthritis (JIA). However, identifying the single nucleotide polymorphisms (SNPs) that drive disease risk is impeded by the SNPs' that identify risk loci being in linkage disequilibrium (LD) with hundreds of other SNPs. Since the causal SNPs remain unknown, it is difficult to identify target genes and use genetic information to inform patient care. We used genotyping and functional data in primary human monocytes/macrophages to nominate disease-driving SNPs on JIA risk haplotypes and identify their likely target genes. Methods: We identified JIA risk haplotypes using Immunochip data from Hinks et al (Nature Gen 2013) and the meta-analysis from McIntosh et al (Arthritis Rheum 2017). We used genotyping data from 3,939 children with JIA and 14,412 healthy controls to identify SNPs that: (1) were situated within open chromatin in multiple immune cell types and (2) were more common in children with JIA than the controls (p< 0.05). We intersected the chosen SNPs (n=846) with regions of bi-directional transcription initiation characteristic of non-coding regulatory regions detected using dREG to analyze GRO-seq data. Finally, we used MicroC data to identify gene promoters interacting with the regulatory regions harboring the candidate causal SNPs. Results: We identified 190 SNPs that overlap with dREG peaks in monocytes and126 SNPs that overlap with dREG peaks in macrophages. Of these SNPs, 101 were situated within dREG peaks in both monocytes and macrophages, suggesting that these SNPs exert their effects independent of the cellular activation state. MicroC data in monocytes identified 20 genes/transcripts whose promoters interact with the enhancers harboring the SNPs of interest. Conclusion: SNPs in JIA risk regions that are candidate causal variants can be further screened using functional data such as GRO-seq. This process identifies a finite number of candidate causal SNPs, the majority of which are likely to exert their biological effects independent of cellular activation state in monocytes. Three-dimensional chromatin data generated with MicroC identifies genes likely to be influenced by these SNPs. These studies demonstrate the importance of investigations into the role of innate immunity in JIA.

High-Resolution Magic Angle Spinning Nuclear Magnetic Resonance Spectroscopy of Paired Clinical Liver Tissue Samples from Hepatocellular Cancer and Surrounding Region.

The global burden of liver cancer is increasing. Timely diagnosis is important for optimising the limited available treatment options. Understanding the metabolic consequences of hepatocellular carcinoma (HCC) may lead to more effective treatment options. We aimed to document metabolite differences between HCC and matched surrounding tissues of varying aetiology, obtained at the time of liver resection, and to interpret metabolite changes with clinical findings. High-resolution magic angle spinning nuclear magnetic resonance (HRMAS-NMR) spectroscopy analyses of N = 10 paired HCC and surrounding non-tumour liver tissue samples were undertaken. There were marked HRMAS-NMR differences in lipid levels in HCC tissue compared to matched surrounding tissue and more subtle changes in low-molecular-weight metabolites, particularly when adjusting for patient-specific variability. Differences in lipid-CH3, lipid-CH2, formate, and acetate levels were of particular interest. The obvious differences in lipid content highlight the intricate interplay between metabolic adaptations and cancer cell survival in the complex microenvironment of liver cancer. Differences in formate and acetate might relate to bacterial metabolites. Therefore, documentation of metabolites in HCC tissue according to histology findings in patients is of interest for personalised medicine approaches and for tailoring targeted treatment strategies.

A systematic strategy for identifying causal single nucleotide polymorphisms and their target genes on Juvenile arthritis risk haplotypes.

BACKGROUND: Although genome-wide association studies (GWAS) have identified multiple regions conferring genetic risk for juvenile idiopathic arthritis (JIA), we are still faced with the task of identifying the single nucleotide polymorphisms (SNPs) on the disease haplotypes that exert the biological effects that confer risk. Until we identify the risk-driving variants, identifying the genes influenced by these variants, and therefore translating genetic information to improved clinical care, will remain an insurmountable task. We used a function-based approach for identifying causal variant candidates and the target genes on JIA risk haplotypes. METHODS: We used a massively parallel reporter assay (MPRA) in myeloid K562 cells to query the effects of 5,226 SNPs in non-coding regions on JIA risk haplotypes for their ability to alter gene expression when compared to the common allele. The assay relies on 180 bp oligonucleotide reporters ("oligos") in which the allele of interest is flanked by its cognate genomic sequence. Barcodes were added randomly by PCR to each oligo to achieve > 20 barcodes per oligo to provide a quantitative read-out of gene expression for each allele. Assays were performed in both unstimulated K562 cells and cells stimulated overnight with interferon gamma (IFNg). As proof of concept, we then used CRISPRi to demonstrate the feasibility of identifying the genes regulated by enhancers harboring expression-altering SNPs. RESULTS: We identified 553 expression-altering SNPs in unstimulated K562 cells and an additional 490 in cells stimulated with IFNg. We further filtered the SNPs to identify those plausibly situated within functional chromatin, using open chromatin and H3K27ac ChIPseq peaks in unstimulated cells and open chromatin plus H3K4me1 in stimulated cells. These procedures yielded 42 unique SNPs (total = 84) for each set. Using CRISPRi, we demonstrated that enhancers harboring MPRA-screened variants in the TRAF1 and LNPEP/ERAP2 loci regulated multiple genes, suggesting complex influences of disease-driving variants. CONCLUSION: Using MPRA and CRISPRi, JIA risk haplotypes can be queried to identify plausible candidates for disease-driving variants. Once these candidate variants are identified, target genes can be identified using CRISPRi informed by the 3D chromatin structures that encompass the risk haplotypes.

Kinetic Resolution of Epimeric Proteins Enables Stereoselective Chemical Mutagenesis.

Chemical mutagenesis via dehydroalanine (Dha) is a powerful method to tailor protein structure and function, allowing the site-specific installation of post-translational modifications and non-natural functional groups. Despite the impressive versatility of this method, applications have been limited, as products are formed as epimeric mixtures, whereby the modified amino acid is present as both the desired l-configuration and a roughly equal amount of the undesired d-isomer. Here, we describe a simple remedy for this issue: removal of the d-isomer via proteolysis using a d-stereoselective peptidase, alkaline d-peptidase (AD-P). We demonstrate that AD-P can selectively cleave the d-isomer of epimeric residues within histone H3, GFP, Ddx4, and SGTA, allowing the installation of non-natural amino acids with stereochemical control. Given the breadth of modifications that can be introduced via Dha and the simplicity of our method, we believe that stereoselective chemoenzymatic mutagenesis will find broad utility in protein engineering and chemical biology applications.

Injectable PEG Hydrogels with Tissue-Like Viscoelasticity Formed through Reversible Alendronate-Calcium Phosphate Crosslinking for Cell-Material Interactions.

Synthetic hydrogels provide controllable 3D environments, which can be used to study fundamental biological phenomena. The growing body of evidence that cell behavior depends upon hydrogel stress relaxation creates a high demand for hydrogels with tissue-like viscoelastic properties. Here, a unique platform of synthetic polyethylene glycol (PEG) hydrogels in which star-shaped PEG molecules are conjugated with alendronate and/or RGD peptides, attaining modifiable degradability as well as flexible cell adhesion, is created. Novel reversible ionic interactions between alendronate and calcium phosphate nanoparticles, leading to versatile viscoelastic properties with varying initial elastic modulus and stress relaxation time, are identified. This new crosslinking mechanism provides shear-thinning properties resulting in differential cellular responses between cancer cells and stem cells. The novel hydrogel system is an improved design to the other ionic crosslink platforms and opens new avenues for the development of pathologically relevant cancer models, as well as minimally invasive approaches for cell delivery for potential regenerative therapies.

Structure-Toxicity Relationship in Intermediate Fibrils from α-Synuclein Condensates.

The aberrant aggregation of α-synuclein (αS) into amyloid fibrils is associated with a range of highly debilitating neurodegenerative conditions, including Parkinson's disease. Although the structural properties of mature amyloids of αS are currently understood, the nature of transient protofilaments and fibrils that appear during αS aggregation remains elusive. Using solid-state nuclear magnetic resonance (ssNMR), cryogenic electron microscopy (cryo-EM), and biophysical methods, we here characterized intermediate amyloid fibrils of αS forming during the aggregation from liquid-like spherical condensates to mature amyloids adopting the structure of pathologically observed aggregates. These transient amyloid intermediates, which induce significant levels of cytotoxicity when incubated with neuronal cells, were found to be stabilized by a small core in an antiparallel ß-sheet conformation, with a disordered N-terminal region of the protein remaining available to mediate membrane binding. In contrast, mature amyloids that subsequently appear during the aggregation showed different structural and biological properties, including low levels of cytotoxicity, a rearranged structured core embedding also the N-terminal region, and a reduced propensity to interact with the membrane. The characterization of these two fibrillar forms of αS, and the use of antibodies and designed mutants, enabled us to clarify the role of critical structural elements endowing intermediate amyloid species with the ability to interact with membranes and induce cytotoxicity.

Determining the factors associated with a prolonged length of stay for adolescent idiopathic scoliosis patients undergoing posterior spinal instrumentation and fusion in a single-payer health care system: are these factors different than those in the United States?

INTRODUCTION: Rapid recovery pathways (RRP) for adolescent idiopathic scoliosis patients undergoing posterior spinal instrumentation and fusion (PSIF) have been shown to be successful in reducing hospital length of stay (LOS). Although the majority of patients are discharged within 3 days, some patients require longer hospital admission. Previous studies in the United States have identified predictors of prolonged LOS for this patient population. The goal of this project was to determine if these predictors are the same for Canadian scoliosis patients and to identify those features which are different under this single-payer system. METHODS: A RRP for scoliosis surgery was implemented in March 2015 at a single, tertiary referral children's hospital in Canada. Previously identified features, along with numerous other patient factors, were collected. Spearman correlations were used to determine the factors most associated with hospital LOS and those factors were used in a multivariable regression model. RESULTS: A total of 161 patients were included in the analysis. Of the previously identified patient factors, only receiving a peri-operative transfusion was found to be significant (ρ = 0.24; p = 0.002). None of the other pre-identified variables were found to be significantly correlated with LOS. Variables not previously examined that were found to be significantly correlated with hospital LOS included ASA status (ρ = 0.19, p = 0.046), fusion involving both the thoracic and lumbar spine (ρ = 0.18, p = 0.025), and receiving celecoxib on post-operative day 1 (ρ = - 0.16; p = 0.038). The features that had the greatest association with LOS through multivariable regression was receiving a blood transfusion (B = 0.48; 95%CI 0.096-0.89; p = 0.017). CONCLUSIONS: In this study, we found that many of the features found to be significantly correlated with prolonged hospital LOS in the United States are not transferable to the Canadian healthcare system. This is important for the Canadian, and other surgeons in a single-payer system, in order to identify pre-operative or immediate post-operative factors that may extend patient LOS following PSIF and plan resources accordingly. LEVEL OF EVIDENCE: III; therapeutic.

Comparison of the three-dimensional chromatin structures of adolescent and adult peripheral blood B cells: implications for the study of pediatric autoimmune diseases.

Background/Purpose: Knowledge of the 3D genome is essential to elucidate genetic mechanisms driving autoimmune diseases. The 3D genome is distinct for each cell type, and it is uncertain whether cell lines faithfully recapitulate the 3D architecture of primary human cells or whether developmental aspects of the pediatric immune system require use of pediatric samples. We undertook a systematic analysis of B cells and B cell lines to compare 3D genomic features encompassing risk loci for juvenile idiopathic arthritis (JIA), systemic lupus (SLE), and type 1 diabetes (T1D). Methods: We isolated B cells from healthy individuals, ages 9-17. HiChIP was performed using CTCF antibody, and CTCF peaks were identified. CTCF loops within the pediatric were compared to three datasets: 1) self-called CTCF consensus peaks called within the pediatric samples, 2) ENCODE's publicly available GM12878 CTCF ChIP-seq peaks, and 3) ENCODE's primary B cell CTCF ChIPseq peaks from two adult females. Differential looping was assessed within the pediatric samples and each of the three peak datasets. Results: The number of consensus peaks called in the pediatric samples was similar to that identified in ENCODE's GM12878 and primary B cell datasets. We observed <1% of loops that demonstrated significantly differential looping between peaks called within the pediatric samples themselves and when called using ENCODE GM12878 peaks . Significant looping differences were even less when comparing loops of the pediatric called peaks to those of the ENCODE primary B cell peaks. When querying loops found in juvenile idiopathic arthritis, type 1 diabetes, or systemic lupus erythematosus risk haplotypes, we observed significant differences in only 2.2%, 1.0%, and 1.3% loops, respectively, when comparing peaks called within the pediatric samples and ENCODE GM12878 dataset. The differences were even less apparent when comparing loops called with the pediatric vs ENCODE adult primary B cell peak datasets.The 3D chromatin architecture in B cells is similar across pediatric, adult, and EBVtransformed cell lines. This conservation of 3D structure includes regions encompassing autoimmune risk haplotypes. Conclusion: Thus, even for pediatric autoimmune diseases, publicly available adult B cell and cell line datasets may be sufficient for assessing effects exerted in the 3D genomic space.

Systemic lupus erythematosus in American Indian/Alaska natives: Incorporating our new understanding of the biology of trauma.

OBJECTIVE: To review the literature regarding systemic lupus erythematosus (SLE) in American Indian/Alaska Native (AI/AN) people and relate prevalence and/or disease severity to our emerging understanding of the biology of trauma and toxic stress. METHODS: We conducted a search and review of the literature using search terms "lupus and American Indians" "ACEs and disease outcome" "Biology of Adversity" "lupus and ACE scores," " lupus and childhood abuse." These search criteria were entered into Google Scholar and articles retrieved from PubMed, NBCI. This approach yielded a small numbers of papers used throughout this review. We excluded articles that were not published in a peer reviewed journals, as well as editorial commentaries. RESULTS: In the AI/AN population, SLE shows high prevalence rates and severe disease manifestations, comparable to the African American population. AI/AN populations also have high rates of childhood trauma. Toxic stress and trauma such as those catalogued in the Adverse Childhood Experiences (ACE) study have broad-reaching immunologic and epigenetic effects that are likely to be relevant to our understanding of SLE in AI/AN people. CONCLUSIONS: AI/AN people have high rates of SLE. These high rates are likely to be driven by many complex factors, not all of which are genetic. Future research is needed to establish (or refute) a causal connection between the biology of adversity and SLE in socially marginalized and historically traumatized populations.

Comparison of the Metabolic Profile between Unstimulated and Stimulated Saliva Samples from Pregnant Women with/without Obesity and Periodontitis.

This study aimed to compare the metabolic profile of unstimulated (US) and stimulated (SS) saliva samples from pregnant women with/without obesity and periodontitis. Ninety-six pregnant women were divided into: obesity + periodontitis (OP = 20); obesity/no periodontitis (OWP = 27); normal BMI + periodontitis (NP = 20); and normal BMI/no periodontitis (NWP = 29). US and SS samples were collected by expectoration and chewing of sterilized parafilm gum, respectively, and samples were individually analyzed by Proton Nuclear Magnetic Resonance (1H-NMR). Univariate (t test and correlations) and multivariate (Principal Component Analysis-PCA, and Partial Least Square-Discriminant Analysis-PLS-DA with Variance Importance Projection-VIP scores) and Metabolite Set Enrichment Analysis were done (p < 0.05). Metabolites commonly found in all groups in elevated concentration in US samples were 5-Aminopentoate, Acetic acid, Butyric acid, Propionic acid, Pyruvic acid, and Succinic acid. They were mainly related to the butyrate metabolism, citric acid cycle, amino sugar metabolism, fatty acids biosynthesis, pyruvate metabolism, glutamate metabolism, and Warburg effect. Metabolites commonly found in all groups that were in elevated concentration in SS samples were Citrulline, Fumaric acid, Histidine, N-acetyl glutamine, N-acetylneuraminic acid, para-hydroxyphenylacetic acid, Proline, Tyrosine. Although some differences were found between unstimulated and stimulated saliva samples from pregnant women with/without obesity and periodontitis, stimulated saliva collection seems adequate, demonstrating similar metabolic pathways to unstimulated saliva samples when groups are compared.

B lymphocytes in treatment-naive paediatric patients with lupus are epigenetically distinct from healthy children.

BACKGROUND: SLE is likely triggered by gene-environment interactions. We have shown that most SLE-associated haplotypes encompass genomic regions enriched for epigenetic marks associated with enhancer function in lymphocytes, suggesting genetic risk is exerted through altered gene regulation. Data remain scarce on how epigenetic variance contributes to disease risk in paediatric SLE (pSLE). We aim to identify differences in epigenetically regulated chromatin architecture in treatment-naive patients with pSLE compared with healthy children. METHODS: Using the assay for transposase-accessible chromatin with sequencing (ATACseq), we surveyed open chromatin in 10 treatment-naive patients with pSLE, with at least moderate disease severity, and 5 healthy children. We investigated whether regions of open chromatin unique to patients with pSLE demonstrate enrichment for specific transcriptional regulators, using standard computational approaches to identify unique peaks and a false discovery rate of <0.05. Further analyses for histone modification enrichment and variant calling were performed using bioinformatics packages in R and Linux. RESULTS: We identified 30 139 differentially accessible regions (DAR) unique to pSLE B cells; 64.3% are more accessible in pSLE than healthy children. Many DAR are found in distal, intergenic regions and enriched for enhancer histone marks (p=0.027). B cells from adult patients with SLE contain more regions of inaccessible chromatin than those in pSLE. In pSLE B cells, 65.2% of the DAR are located within or near known SLE haplotypes. Further analysis revealed enrichment of transcription factor binding motifs within these DAR that may regulate genes involved in pro-inflammatory responses and cellular adhesion. CONCLUSIONS: We demonstrate an epigenetically distinct profile in pSLE B cells when compared with healthy children and adults with lupus, indicating that pSLE B cells are predisposed for disease onset/development. Increased chromatin accessibility in non-coding genomic regions controlling activation of inflammation suggest that transcriptional dysregulation by regulatory elements controlling B cell activation plays an important role in pSLE pathogenesis.

Association of anti-TPM4 autoantibodies with vasculopathic cutaneous manifestations in juvenile dermatomyositis.

OBJECTIVES: AECAs are detected in multiple forms of vasculitis or vasculopathy, including JDM. High levels of tropomyosin alpha-4 chain (TPM4) gene expression in cutaneous lesions and TPM4 protein expression in some endothelial cells (ECs) have been proven. Furthermore, the presence of autoantibodies to tropomyosin proteins have been discovered in DM. We therefore investigated whether anti-TPM4 autoantibodies are an AECA in JDM and are correlated with clinical features of JDM. METHODS: The expression of TPM4 protein in cultured normal human dermal microvascular ECs was investigated by Western blotting. Plasma samples from 63 children with JDM, 50 children with polyarticular JIA (pJIA) and 40 healthy children (HC) were tested for the presence of anti-TPM4 autoantibodies using an ELISA. Clinical features were compared between JDM patients with and without anti-TPM4 autoantibodies. RESULTS: Autoantibodies to TPM4 were detected in the plasma of 30% of JDM, 2% of pJIA (P < 0.0001) and 0% of HC (P < 0.0001). In JDM, anti-TPM4 autoantibodies were associated with the presence of cutaneous ulcers (53%; P = 0.02), shawl sign rash (47%; P = 0.03), mucous membrane lesions (84%; P = 0.04) and subcutaneous edema (42%; P < 0.05). Anti-TPM4 autoantibodies significantly correlated with the use of intravenous steroids and IVIG therapy in JDM (both P = 0.01). The total number of medications received was higher in patients with anti-TPM4 autoantibodies (P = 0.02). CONCLUSION: Anti-TPM4 autoantibodies are detected frequently in children with JDM and are novel myositis-associated autoantibodies. Their presence correlates with vasculopathic and other cutaneous manifestations of JDM that may be indicative of more refractory disease.

Versatile Diphosphine Chelators for Radiolabeling Peptides with 99mTc and 64Cu.

We have developed a diphosphine (DP) platform for radiolabeling peptides with 99mTc and 64Cu for molecular SPECT and PET imaging, respectively. Two diphosphines, 2,3-bis(diphenylphosphino)maleic anhydride (DPPh) and 2,3-bis(di-p-tolylphosphino)maleic anhydride (DPTol), were each reacted with a Prostate Specific Membrane Antigen-targeted dipeptide (PSMAt) to yield the bioconjugates DPPh-PSMAt and DPTol-PSMAt, as well as an integrin-targeted cyclic peptide, RGD, to yield the bioconjugates DPPh-RGD and DPTol-RGD. Each of these DP-PSMAt conjugates formed geometric cis/trans-[MO2(DPX-PSMAt)2]+ (M = 99mTc, 99gTc, natRe; X = Ph, Tol) complexes when reacted with [MO2]+ motifs. Furthermore, both DPPh-PSMAt and DPTol-PSMAt could be formulated into kits containing reducing agent and buffer components, enabling preparation of the new radiotracers cis/trans-[99mTcO2(DPPh-PSMAt)2]+ and cis/trans-[99mTcO2(DPTol-PSMAt)2]+ from aqueous 99mTcO4- in 81% and 88% radiochemical yield (RCY), respectively, in 5 min at 100 °C. The consistently higher RCYs observed for cis/trans-[99mTcO2(DPTol-PSMAt)2]+ are attributed to the increased reactivity of DPTol-PSMAt over DPPh-PSMAt. Both cis/trans-[99mTcO2(DPPh-PSMAt)2]+ and cis/trans-[99mTcO2(DPTol-PSMAt)2]+ exhibited high metabolic stability, and in vivo SPECT imaging in healthy mice revealed that both new radiotracers cleared rapidly from circulation, via a renal pathway. These new diphosphine bioconjugates also furnished [64Cu(DPX-PSMAt)2]+ (X = Ph, Tol) complexes rapidly, in a high RCY (>95%), under mild conditions. In summary, the new DP platform is versatile: it enables straightforward functionalization of targeting peptides with a diphosphine chelator, and the resulting bioconjugates can be simply radiolabeled with both the SPECT and PET radionuclides, 99mTc and 64Cu, in high RCYs. Furthermore, the DP platform is amenable to derivatization to either increase the chelator reactivity with metallic radioisotopes or, alternatively, modify the radiotracer hydrophilicity. Functionalized diphosphine chelators thus have the potential to provide access to new molecular radiotracers for receptor-targeted imaging.

Probing Unexpected Reactivity in Radiometal Chemistry: Indium-111-Mediated Hydrolysis of Hybrid Cyclen-Hydroxypyridinone Ligands.

Chelators based on hydroxypyridinones have utility in incorporating radioactive metal ions into diagnostic and therapeutic agents used in nuclear medicine. Over the course of our hydroxypyridinone studies, we have prepared two novel chelators, consisting of a cyclen (1,4,7,10-tetraazacyclododecane) ring bearing two pendant hydroxypyridinone groups, appended via methylene acetamide motifs at either the 1,4-positions (L1) or 1,7-positions (L2) of the cyclen ring. In radiolabeling reactions of L1 or L2 with the γ-emitting radioisotope, [111In]In3+, we have observed radiometal-mediated hydrolysis of a single amide group of either L1 or L2. The reaction of either [111In]In3+ or [natIn]In3+ with either L1 or L2, in aqueous alkaline solutions at 80 °C, initially results in formation of [In(L1)]+ or [In(L2)]+, respectively. Over time, each of these species undergoes In3+-mediated hydrolysis of a single amide group to yield species in which In3+ remains coordinated to the resultant chelator, which consists of a cyclen ring bearing a single hydroxypyridinone group and a single carboxylate group. The reactivity toward hydrolysis is higher for the L1 complex compared to that for the L2 complex. Density functional theory calculations corroborate these experimental findings and importantly indicate that the activation energy required for the hydrolysis of L1 is significantly lower than that required for L2. This is the first reported example of a chelator undergoing radiometal-mediated hydrolysis to form a radiometalated complex. It is possible that metal-mediated amide bond cleavage is a source of instability in other radiotracers, particularly those in which radiometal complexation occurs in aqueous, basic solutions at high temperatures. This study highlights the importance of appropriate characterization of radiolabeled products.

The effect of vertebral body tethering on spine range of motion in adolescent idiopathic scoliosis: a pilot study.

PURPOSE: Posterior spinal fusion and instrumentation (PSF) and vertebral body tethering (VBT) are corrective surgical techniques used in treating adolescent idiopathic scoliosis (AIS). Comparing the preservation of spine range of motion (ROM) following PSF and VBT for treatment of AIS has yet to be explored. The purpose of this work was to retrospectively compare global spine ROM in adolescents (9-18 years of age) without spine deformity, adolescents with untreated AIS, adolescents having undergone PSF, and adolescents having undergone VBT to gain insight on the effect of VBT on spine motion. METHODS: Twenty participants were recruited into four groups including Control (n = 6), untreated AIS (n = 5), post-operative PSF (n = 4) and post-operative VBT (n = 5). Three-dimensional kinematics of the spine were collected and analyzed using an intersegmental spine model during constrained forward flexion, right-left lateral bending, and right-left axial twist movements. RESULTS: The PSF group displayed significantly lower spine ROM than the two non-operative groups during thoracic and total left axial twist (p ≤ 0.048), whereas thoracic and total ROM during right-left lateral bending is almost equally lower in the PSF (p ≤ 0.03) and VBT (p ≤ 0.01) groups when compared to the Control and AIS groups. CONCLUSION: These results suggest some preservation of spine motion in the transverse plane following VBT. This study provides initial evidence of some potential preservation of spine ROM following VBT; however, further prospective investigation of VBT is needed to assess and confirm these hypotheses.

Analysis of chromatin data supports a role for CD14+ monocytes/macrophages in mediating genetic risk for juvenile idiopathic arthritis.

Introduction: Genome wide association studies (GWAS) have identified multiple regions that confer genetic risk for the polyarticular/oligoarticular forms of juvenile idiopathic arthritis (JIA). However, genome-wide scans do not identify the cells impacted by genetic polymorphisms on the risk haplotypes or the genes impacted by those variants. We have shown that genetic variants driving JIA risk are likely to affect both innate and adaptive immune functions. We provide additional evidence that JIA risk variants impact innate immunity. Materials and methods: We queried publicly available H3K4me1/H3K27ac ChIP-seq data in CD14+ monocytes to determine whether the linkage disequilibrium (LD) blocks incorporating the SNPs that tag JIA risk loci showed enrichment for these epigenetic marks. We also queried monocyte/macrophage GROseq data, a functional readout of active enhancers. We defined the topologically associated domains (TADs) encompassing enhancers on the risk haplotypes and identified genes within those TADs expressed in monocytes. We performed ontology analyses of these genes to identify cellular processes that may be impacted by these variants. We also used whole blood RNAseq data from the Genotype-Tissue Expression (GTEx) data base to determine whether SNPs lying within monocyte GROseq peaks influence plausible target genes within the TADs encompassing the JIA risk haplotypes. Results: The LD blocks encompassing the JIA genetic risk regions were enriched for H3K4me1/H3K27ac ChIPseq peaks (p=0.00021 and p=0.022) when compared to genome background. Eleven and sixteen JIA were enriched for resting and activated macrophage GROseq peaks, respectively risk regions (p=0.04385 and p=0.00004). We identified 321 expressed genes within the TADs encompassing the JIA haplotypes in human monocytes. Ontological analysis of these genes showed enrichment for multiple immune functions. Finally, we found that SNPs lying within the GROseq peaks are strongly associated with expression levels of plausible target genes in human whole blood. Conclusions: These findings support the idea that both innate and adaptive immunity are impacted by JIA genetic risk variants.

Health inequities in the rheumatic diseases of childhood.

PURPOSE OF REVIEW: To describe differences in disease manifestations and outcomes in pediatric rheumatic diseases as they occur in non-European-descended populations in North America. RECENT FINDINGS: Differences in disease prevalence, clinical phenotypes, disease course, and outcomes have been described across the spectrum of pediatric-onset rheumatic diseases. Although these differences are commonly explained by differences in genetic risk or access to tertiary healthcare facilities, our emerging understanding of the immunobiology of historical/ongoing trauma suggest a more complex explanation for these observed differences. SUMMARY: Health inequities as observed in pediatric rheumatic diseases are likely to emerge from a complex interplay between social and biological factors. The important contribution of historical and repetitive trauma deserves further exploration.

Chromatin architecture around stroke haplotypes provides evidence that genetic risk is conferred through vascular cells.

Introduction: Genome-wide association studies (GWAS) have identified numerous stroke-associated SNPs. To understand how SNPs affect gene expression related to increased stroke risk, we studied epigenetic landscapes surrounding 26 common, validated stroke-associated loci. Methods: We mapped the SNPs to linkage disequilibrium (LD) blocks and examined H3K27ac, H3K4me1, H3K9ac, and H3K4me3 histone marks and transcription-factor binding-sites in pathologically relevant cell types (hematopoietic and vascular cells). Hi-C data were used to identify topologically associated domains (TADs) encompassing the LD blocks and overlapping genes. Results: Fibroblasts, smooth muscle, and endothelial cells showed significant enrichment for enhancer-associated marks within stroke-associated LD blocks. Genes within encompassing TADs reflected vessel homeostasis, cellular turnover, and enzymatic activity. Conclusions: Stroke-associated genetic variants confer risk predominantly through vascular cells rather than hematopoietic cell types.

Previous studies have found several variations in the DNA sequence (known as single nucleotide polymorphisms) linked to higher stroke risk. But the mechanisms behind how they increase risk is unknown. One hypothesis is that they affect non-coding DNA elements (i.e., epigenetics), which in turn drive abnormal changes in gene expression leading to increased stroke risk. To investigate this potential mechanism, we mined publicly available, cell-type specific databases. We searched for overlap between the regions with polymorphisms and regions where DNA transcription machinery bind (i.e., enhancers, transcription factor binding sites). We found that fibroblasts and smooth muscle cells (cells in vessel walls) had more of these DNA elements in regions associated with stroke risk. Bioinformatics analyses of genes that could be affected by changes in these elements were linked to stroke-related mechanisms.