Santalol Isomers Inhibit Transthyretin Amyloidogenesis and Associated Pathologies in Caenorhabditis elegans.

Transthyretin (TTR) is a homotetrameric protein found in human serum and is implicated in fatal inherited amyloidoses. Destabilization of native TTR confirmation resulting from mutation, environmental changes, and aging causes polymerization and amyloid fibril formation. Although several small molecules have been reported to stabilize the native state and inhibit TTR aggregation, prolonged use can cause serious side effects. Therefore, pharmacologically enhancing the degradation of TTR aggregates and kinetically stabilizing the native tetrameric structure with bioactive molecule(s) could be a viable therapeutic strategy to hinder the advancement of TTR amyloidoses. In this context, here we demonstrated α- and ß-santalol, natural sesquiterpenes from sandalwood, as a potent TTR aggregation inhibitor and native state stabilizer using combined in vitro, in silico, and in vivo experiments. We found that α- and ß-santalol synergize to reduce wild-type (WT) and Val30Met (V30M) mutant TTR aggregates in novel C. elegans strains expressing TTR fragments fused with a green fluorescent protein in body wall muscle cells. α- and ß-Santalol extend the lifespan and healthspan of C. elegans strains carrying TTRWT::EGFP and TTRV30M::EGFP transgene by activating the SKN-1/Nrf2, autophagy, and proteasome. Moreover, α- and ß-santalol directly interacted with TTR and reduced the flexibility of the thyroxine-binding cavity and homotetramer interface, which in turn increases stability and prevents the dissociation of the TTR tetramer. These data indicate that α- and ß-santalol are the strong natural therapeutic intervention against TTR-associated amyloid diseases.

Predicting quorum sensing peptides using stacked generalization ensemble with gradient boosting based feature selection.

Bacteria exist in natural environments for most of their life as complex, heterogeneous, and multicellular aggregates. Under these circumstances, critical cell functions are controlled by several signaling molecules known as quorum sensing (QS) molecules. In Gram-positive bacteria, peptides are deployed as QS molecules. The development of antibodies against such QS molecules has been identified as a promising therapeutic intervention for bacterial control. Hence, the identification of QS peptides has received considerable attention. Availability of a fast and reliable predictive model to effectively identify QS peptides can help the existing high throughput experiments. In this study, a stacked generalization ensemble model with Gradient Boosting Machine (GBM)-based feature selection, namely EnsembleQS was developed to predict QS peptides with high accuracy. On selected GBM features (791D), the EnsembleQS outperformed finely tuned baseline classifiers and demonstrated robust performance, indicating the superiority of the model. The accuracy of EnsembleQS is 4% higher than those resulting from ensemble model on hybrid dataset. When evaluating an independent data set of 40 QS peptides, the EnsembleQS model showed an accuracy of 93.4% with Matthew's Correlation Coefficient (MCC) and area under the ROC curve (AUC) values of 0.91 and 0.951, respectively. These results suggest that EnsembleQS will be a useful computational framework for predicting QS peptides and will efficiently support proteomics research. The source code and all datasets used in this study are publicly available at https://github.com/proteinexplorers/EnsembleQS .

Autosegmentation based on different-sized training datasets of consistently-curated volumes and impact on rectal contours in prostate cancer radiation therapy.

Background and purpose: Autosegmentation techniques are emerging as time-saving means for radiation therapy (RT) contouring, but the understanding of their performance on different datasets is limited. The aim of this study was to determine agreement between rectal volumes by an existing autosegmentation algorithm and manually-delineated rectal volumes in prostate cancer RT. We also investigated contour quality by different-sized training datasets and consistently-curated volumes for retrained versions of this same algorithm. Materials and methods: Single-institutional data from 624 prostate cancer patients treated to 50-70 Gy were used. Manually-delineated clinical rectal volumes (clinical) and consistently-curated volumes recontoured to one anatomical guideline (reference) were compared to autocontoured volumes by a commercial autosegmentation tool based on deep-learning (v1; n = 891, multiple-institutional data) and retrained versions using subsets of the curated volumes (v32/64/128/256; n = 32/64/128/256). Evaluations included dose-volume histogram metrics, Dice similarity coefficients, and Hausdorff distances; differences between groups were quantified using parametric or non-parametric hypothesis testing. Results: Volumes by v1-256 (76-78 cm3) were larger than reference (75 cm3) and clinical (76 cm3). Mean doses by v1-256 (24.2-25.2 Gy) were closer to reference (24.2 Gy) than to clinical (23.8 Gy). Maximum doses were similar for all volumes (65.7-66.0 Gy). Dice for v1-256 and reference (0.87-0.89) were higher than for v1-256 and clinical (0.86-0.87) with corresponding Hausdorff comparisons including reference smaller than comparisons including clinical (5-6 mm vs. 7-8 mm). Conclusion: Using small single-institutional RT datasets with consistently-defined rectal volumes when training autosegmentation algorithms created contours of similar quality as the same algorithm trained on large multi-institutional datasets.

Expression of cell type incongruent alpha-cardiac actin 1 subunit in medulloblastoma reveals a novel mechanism for cancer cell survival and control of migration.

BACKGROUND: Alterations in actin subunit expression have been reported in multiple cancers, but have not been investigated previously in medulloblastoma. METHODS: Bioinformatic analysis of multiple medulloblastoma tumor databases was performed to profile ACTC1 mRNA levels. Western blot was used to verify protein expression in established medulloblastoma cell lines. Immunofluorescence microscopy was performed to assess ACTC1 localization. Stable cell lines with ACTC1 overexpression were generated and shRNA knockdown of ACTC1 was accomplished. We used PARP1 cleavage by Western blot as a marker of apoptosis and cell survival was determined by FACS viability assay and colony formation. Cell migration with overexpression or knockdown of ACTC1 was determined by the scratch assay. Stress fiber length distribution was assessed by fluorescence microscopy. RESULTS: ACTC1 mRNA expression is highest in SHH and WNT medulloblastoma among all subgroups. ACTC1 protein was confirmed by Western blot in SHH subgroup and Group 3 subgroup cell lines with the lowest expression in Group 3 cells. Microscopy demonstrated ACTC1 co-localization with F-actin. Overexpression of ACTC1 in Group 3 cells abolished the apoptotic response to Aurora kinase B inhibition. Knockdown of ACTC1 in SHH cells and in Myc overexpressing SHH cells induced apoptosis, impaired colony formation, and inhibited migration. Changes in stress fiber length distribution in medulloblastoma cells are induced by alterations in ACTC1 abundance. CONCLUSIONS: Alpha-cardiac actin (ACTC1) is expressed in SHH medulloblastoma. Expression of this protein in medulloblastoma modifies stress fiber composition and functions in promoting resistance to apoptosis induced by mitotic inhibition, enhancing cell survival, and controlling migration.

The remodelling of actin composition as a hallmark of cancer.

Actin is a key structural protein that makes up the cytoskeleton of cells, and plays a role in functions such as division, migration, and vesicle trafficking. It comprises six different cell-type specific isoforms: ACTA1, ACTA2, ACTB, ACTC1, ACTG1, and ACTG2. Abnormal actin isoform expression has been reported in many cancers, which led us to hypothesize that it may serve as an early biomarker of cancer. We show an overview of the different actin isoforms and highlight mechanisms by which they may contribute to tumorigenicity. Furthermore, we suggest how the aberrant expression of actin subunits can confer cells with greater proliferation ability, increased migratory capability, and chemoresistance through incorporation into the normal cellular F-actin network and altered actin binding protein interaction. Studying this fundamental change that takes place within cancer cells can further our understanding of neoplastic transformation in multiple tissue types, which can ultimately aid in the early-detection, diagnosis and treatment of cancer.

Adoptive transfer of immature myeloid cells lacking NF-κB p50 (p50-IMC) impedes the growth of MHC-matched high-risk neuroblastoma.

High-risk neuroblastomas harbor abundant myeloid cells that suppress antitumor immunity and support tumor growth. Macrophages lacking the inhibitory NF-κB p50 subunit adopt a pro-inflammatory phenotype. We now report that murine 9464D neuroblastoma cells, which express high levels of exogenous MYCN, grow slower in syngeneic p50(f/f);Lys-Cre mice that lack p50 in macrophages and neutrophils, compared with p50(f/f) littermates. Tumors in p50(f/f);Lys-Cre mice possess increased numbers of total and activated CD4+ and CD8+ T cells, and depletion of both of these T-cell populations accelerates tumor growth. Anti-PD-1 T-cell checkpoint blockade, or DNA methyltransferase and histone deacetylase inhibition, further slows tumor growth. In addition, adoptive transfer of immature myeloid cells lacking NF-κB p50 (p50-IMC), generated either from the bone marrow of p50-/- mice or via nucleofection of a p50 sgRNA:Cas9 complex into wild-type hematopoietic progenitors, also slowed growth of MHC-matched 9464D tumors but not of MHC-mismatched Neuro2A tumors. These findings further validate the utility of targeting myeloid NF-κB p50 as a strategy for cancer therapy and demonstrate activity of p50-IMC generated by gene editing of syngeneic marrow cells, a cell product relevant to clinical translation.

NF-κB p50-deficient immature myeloid cell (p50-IMC) adoptive transfer slows the growth of murine prostate and pancreatic ductal carcinoma.

BACKGROUND: Macrophages and dendritic cells lacking the transcription factor nuclear factor kappa B p50 are skewed toward a proinflammatory phenotype, with increased cytokine expression and enhanced T cell activation; additionally, murine melanoma, fibrosarcoma, colon carcinoma, and glioblastoma grow slower in p50-/- mice. We therefore evaluated the efficacy of p50-negative immature myeloid cells (p50-IMCs) adoptively transferred into tumor-bearing hosts. Immature cells were used to maximize tumor localization, and pretreatment with 5-fluorouracil (5FU) was examined due to its potential to impair marrow production of myeloid cells, to target tumor myeloid cells and to release tumor neoantigens. METHODS: Wild-type (WT)-IMC or p50-IMC were generated by culturing lineage-negative marrow cells from WT or p50-/- mice in media containing thrombopoietin, stem cell factor and Flt3 ligand for 6 days followed by monocyte colony-stimulating factor for 1 day on ultralow attachment plates. Mice inoculated with Hi-Myc prostate cancer (PCa) cells or K-RasG12D pancreatic ductal carcinoma (PDC)-luciferase cells received 5FU followed 5 days later by three doses of 107 immature myeloid cells (IMC) every 3-4 days. RESULTS: PCa cells grew slower in p50-/- mice, and absence of host p50 prolonged the survival of mice inoculated orthotopically with PDC cells. IMC from Cytomegalovirus (CMV)-luciferase mice localized to tumor, nodes, spleen, marrow, and lung. 5FU followed by p50-IMC slowed PCa and PDC tumor growth, ~3-fold on average, in contrast to 5FU followed by WT-IMC, 5FU alone or p50-IMC alone. Slowed tumor growth was evident for 93% of PCa but only 53% of PDC tumors; we therefore focused on PCa for additional IMC analyses. In PCa, p50-IMC matured into F4/80+ macrophages, as well as CD11b+F4/80-CD11c+ conventional dendritic cells (cDCs). In both tumor and draining lymph nodes, p50-IMC generated more macrophages and cDCs than WT-IMC. Activated tumor CD8+ T cells were increased fivefold by p50-IMC compared with WT-IMC, and antibody-mediated CD8+ T cell depletion obviated slower tumor growth induced by 5FU followed by p50-IMC. CONCLUSIONS: 5FU followed by p50-IMC slows the growth of murine prostate and pancreatic carcinoma and depends on CD8+ T cell activation. Deletion of p50 in patient-derived marrow CD34+ cells and subsequent production of IMC for adoptive transfer may contribute to the therapy of these and additional cancers.

Challenges in Clinical Management of Radiation-Induced Illnesses During Exploration Spaceflight.

INTRODUCTION: Analysis of historical solar particle events (SPEs) provides context for some understanding of acute radiation exposure risk to astronauts who will travel outside of low-Earth orbit. Predicted levels of radiation exposures to exploration crewmembers could produce some health impacts, including nausea, emesis, and fatigue, though more severe clinical manifestations are unlikely. Using current models of anticipated physiological sequelae, we evaluated the clinical challenges of managing radiation-related clinical concerns during exploration spaceflight.METHODS: A literature review was conducted to identify terrestrial management standards for radiation-induced illnesses, focusing on prodromal symptom treatment. Terrestrial management was compared to current spaceflight medical capabilities to identify gaps and highlight challenges involved in expanding capabilities for future exploration spaceflight.RESULTS: Current spaceflight medical resources, such as those found on the International Space Station, may be sufficient to manage some aspects of radiation-induced illness, although effective treatment of all potential manifestations would require substantial expansion of capabilities. Terrestrial adjunctive therapies or more experimental treatments are unavailable in current spaceflight medical capabilities but may have a role in future management of acute radiation exposure.DISCUSSION: Expanded medical capabilities for managing radiation-induced illnesses could be included onboard future exploration vehicles. However, this would require substantial research, time, and funding to reach flight readiness, and vehicle limitations may restrict such capabilities for exploration missions. The benefits of including expanded capabilities should be weighed against the likelihood of significant radiation exposure and extensive mission design constraints.Blue RS, Chancellor JC, Suresh R, Carnell LS, Reyes DP, Nowadly CD, Antonsen EL. Challenges in clinical management of radiation-induced illnesses during exploration spaceflight. Aerosp Med Hum Perform. 2019; 90(11):966-977.

Progression from the Common Lymphoid Progenitor to B/Myeloid PreproB and ProB Precursors during B Lymphopoiesis Requires C/EBPα.

The C/EBPα transcription factor is required for myelopoiesis, with prior observations suggesting additional contributions to B lymphopoiesis. Cebpa expression is evident in common lymphoid progenitor (CLP) and preproB cells but is absent in proB and preB cells. We previously observed that marrow lacking the Cebpa +37 kb enhancer is impaired in producing B cells upon competitive transplantation. Additionally, a Cebpa enhancer/promoter-hCD4 transgene is expressed in B/myeloid CFU. Extending these findings, pan-hematopoietic murine Cebpa enhancer deletion using Mx1-Cre leads to expanded CLP, fewer preproB cells, markedly reduced proB and preB cells, and reduced mature B cells, without affecting T cell numbers. In contrast, enhancer deletion at the proB stage using Mb1-Cre does not impair B cell maturation. Further evaluation of CLP reveals that the Cebpa transgene is expressed almost exclusively in Flt3+ multipotent CLP versus B cell-restricted Flt3- CLP. In vitro, hCD4+ preproB cells produce both B and myeloid cells, whereas hCD4- preproB cells only produce B cells. Additionally, a subset of hCD4- preproB cells express high levels of RAG1-GFP, as seen also in proB cells. Global gene expression analysis indicates that hCD4+ preproB cells express proliferative pathways, whereas B cell development and signal transduction pathways predominate in hCD4- preproB cells. Consistent with these changes, Cebpa enhancer-deleted preproB cells downmodulate cell cycle pathways while upregulating B cell signaling pathways. Collectively, these findings indicate that C/EBPα is required for Flt3+ CLP maturation into preproB cells and then for proliferative Cebpaint B/myeloid preproB cells to progress to Cebpalo B cell-restricted preproB cells and finally to Cebpaneg proB cells.

Pro-inflammatory cytokine Interleukin-1ß (IL-1ß) controls Leishmania infection.

Leishmania is an obligate intracellular parasite uses low pH phagolysosomal compartments of host macrophages as their final abode. IL-1ß is a pro inflammatory cytokine, which is secreted by immune cells to trigger inflammation and this has been found profoundly in the lesions caused by Leishmania pathogens. But the specific role of this cytokine on host cell macrophages during infection has not been fully explored. Here in, we have showed that prolonged exposure of IL-1ß on macrophages increases the parasite burden. Pre-treatment of bone marrow derived macrophages (BMDM) with IL-1ß also generates significantly higher amount of anti-inflammatory cytokine IL-10. As IL-10 plays crucial role in the establishment of infection, enhanced production of IL-10 observed upon IL-1ß treatment could contribute to the progression of the disease. By quantifying the production of Nitric oxide (NO), we further report that the pretreatment of IL-1ß fails to produce the nitric oxide. By measuring the footpad thickness in two different mice strains of differential susceptibility we showed IL-1ß treatment increases parasitic burden. As our results shows that the exposure of IL-1ß helps in disease progression, IL-1ß signalling may be an attractive target for future therapeutic intervention.

Absence of host NF-κB p50 induces murine glioblastoma tumor regression, increases survival, and decreases T-cell induction of tumor-associated macrophage M2 polarization.

High-grade gliomas harbor abundant myeloid cells that suppress anti-tumor immunity and support tumor growth. Targeting transcription factors, such as NF-κB p50, that mediate suppressive myeloid M2 polarization may prove therapeutic. GL261-Luc glioblastoma cells were inoculated into wild-type and p50-/- mice, followed by analysis of tumor growth, survival, tumor myeloid cells, and T cells. The absence of host p50 slows tumor growth and enables regression in 30% of recipients, leading to prolonged survival. Tumors developing in p50-/- mice possess a greater concentration of tumor-infiltrating myeloid cells (TIMs) than those in wild-type mice. TIMs are predominantly F4/80hi macrophages which, along with tumor-associated microglia, express increased pro-inflammatory M1 and reduced immune-suppressive M2 markers. In p50-/- mice, total tumor CD4 T cells are threefold more abundant, whereas CD8 T-cell numbers are unchanged, and both produce increased IFNγ and Granzyme B. Naïve splenic p50-/- CD8 T cells manifest increased activation, whereas naïve p50-/- and WT CD4 T cells show similar Th1, Th2, and Th17 polarization. Antibody targeting CD4, but not CD8, fully obviates the p50-/- survival advantage. Combined CD4 and CD8 T-cell depletion reverses myeloid M2 polarization in wild-type hosts, without affecting myeloid M1 polarization in p50-/- hosts. Finally, gliomas grow similarly in p50(f/f) and p50(f/f);Lysozyme-Cre mice, the latter having reduced p50 specifically in myeloid cells and tumor microglia. Thus, high-grade glioma T cells play a key role in directing M2 polarization of tumor myeloid cells, and reducing NF-κB p50 in both tumor myeloid cells and T cells may contribute to glioma therapy.

Do not fear the Framingham: Practical application to properly evaluate and modify cardiovascular risk in commercial divers.

INTRODUCTION: In April 2016 the Association of Diving Contractors International (ADCI) consensus guidelines began recommending annual cardiovascular risk stratification of commercial divers using the Framingham Risk Score (FRS). For those at elevated risk, further testing is recommended. This approach has raised concerns about potential operational and financial impacts. However, the prevalence of elevated cardiovascular risk and need for additional testing among commercial divers is not known. METHODS: Clinical data required to calculate the FRS was abstracted for 190 commercial divers in two cohorts. Population demographics, FRS distribution, contributions of risk factors and effect of interventions on reducing risk-factor burden were assessed. RESULTS: Mean FRS score was 1.68 ± 6.35 points, with 13 divers (6.8%) at intermediate risk and none at high 10-year risk. In these 13 divers, the mean contributions to the FRS were from age (6.5 points), cholesterol (3.1 pts.), smoking (1.3 pts.), highdensity lipoprotein (1 pt.), and systolic blood pressure (0.8 pts). The youngest age group had a significantly higher modifiable risk core than the oldest age group (5.87 vs. 1.2 points, P ⟨ 0.001). All 13 intermediate risk divers could have been reclassified as low-risk with successful treatment of modifiable risk factors. DISCUSSION: The prevalence of elevated cardiovascular risk among commercial divers is low, and treatment of modifiable risk factors could reclassify those at intermediate risk to low risk. Therefore, FRS implementation coupled with intensive risk-reduction strategies for at risk-divers may help improve diver health and prolong the careers of divers while limiting the need for additional testing and adverse operational impact.

Absence of myeloid Klf4 reduces prostate cancer growth with pro-atherosclerotic activation of tumor myeloid cells and infiltration of CD8 T cells.

The microenvironment of prostate cancer often includes abundant tumor-associated macrophages (TAMs), with their acquisition of an M2 phenotype correlating with local aggressiveness and metastasis. Tumor-derived M-CSF contributes to TAM M2 polarization, and M-CSF receptor inhibition slows prostate cancer growth in model systems. As additional cytokines can direct TAM M2 polarization, targeting downstream transcription factors could avoid resistance. Klf4 and C/EBPß each contribute to monocyte development, and reduced expression of macrophage Klf4 or C/EBPß favors their adoption of a pro-inflammatory M1 state. We find that a Hi-Myc C57BL/6 prostate cancer line grows more slowly in syngeneic Klf4(f/f);Lys-Cre compared with Klf4(f/f) mice when inoculated subcutaneously, but grows equally rapidly in C/EBPß(f/f);Lys-Cre and C/EBPß(f/f) hosts. In the absence of myeloid Klf4, TAMs have reduced expression of surface mannose receptor and Fizz1 mRNA, both M2 markers. Global gene expression analysis further revealed activation of pro-inflammatory, pro-atherosclerotic pathways. Analysis of tumor-infiltrating lymphocytes (TILs) demonstrated markedly increased activated CD8 T cell numbers, and CD8 T cell depletion obviated the inhibitory effect of myeloid Klf4 deletion on prostate cancer growth. These findings suggest that reducing expression or activity of the Klf4 transcription factor in tumor myeloid cells may contribute to prostate cancer therapy.

Sustained Accelerated Idioventricular Rhythm in a Centrifuge-Simulated Suborbital Spaceflight.

INTRODUCTION: Hypergravitational exposures during human centrifugation are known to provoke dysrhythmias, including sinus dysrhythmias/tachycardias, premature atrial/ventricular contractions, and even atrial fibrillations or flutter patterns. However, events are generally short-lived and resolve rapidly after cessation of acceleration. This case report describes a prolonged ectopic ventricular rhythm in response to high G exposure. CASE REPORT: A previously healthy 30-yr-old man voluntarily participated in centrifuge trials as a part of a larger study, experiencing a total of 7 centrifuge runs over 48 h. Day 1 consisted of two +Gz runs (peak +3.5 Gz, run 2) and two +Gx runs (peak +6.0 Gx, run 4). Day 2 consisted of three runs approximating suborbital spaceflight profiles (combined +Gx and +Gz). Hemodynamic data collected included blood pressure, heart rate, and continuous three-lead electrocardiogram. Following the final acceleration exposure of the last Day 2 run (peak +4.5 Gx and +4.0 Gz combined, resultant +6.0 G), during a period of idle resting centrifuge activity (resultant vector +1.4 G), the subject demonstrated a marked change in his three-lead electrocardiogram from normal sinus rhythm to a wide-complex ectopic ventricular rhythm at a rate of 91-95 bpm, consistent with an accelerated idioventricular rhythm (AIVR). This rhythm was sustained for 2 m, 24 s before reversion to normal sinus. The subject reported no adverse symptoms during this time. DISCUSSION: While prolonged, the dysrhythmia was asymptomatic and self-limited. AIVR is likely a physiological response to acceleration and can be managed conservatively. Vigilance is needed to ensure that AIVR is correctly distinguished from other, malignant rhythms to avoid inappropriate treatment and negative operational impacts.Suresh R, Blue RS, Mathers C, Castleberry TL, Vanderploeg JM. Sustained accelerated idioventricular rhythm in a centrifuge-simulated suborbital spaceflight. Aerosp Med Hum Perform. 2017; 88(8):789-793.

Utility of real-time three-dimensional echocardiography in improved assessment of a mitral valve papillary fibroelastoma.

Primary cardiac tumors are exceedingly rare. They are usually first identified by transthoracic echocardiography. However, transesophageal echocardiography (TEE), with the aid of real-time three-dimensional (3D) imaging, can provide additional important mass characteristics. We present a case that demonstrates the usefulness of 3D TEE in characterizing a papillary fibroelastoma.

Complement-mediated 'bystander' damage initiates host NLRP3 inflammasome activation.

Complement activation has long been associated with inflammation, primarily due to the elaboration of the complement anaphylotoxins C5a and C3a. In this work, we demonstrate that the phagocytosis of complement-opsonized particles promotes host inflammatory responses by a new mechanism that depends on the terminal complement components (C5b-C9). We demonstrate that during the phagocytosis of complement-opsonized particles, the membrane attack complex (MAC) of complement can be transferred from the activating particle to the macrophage plasma membrane by a 'bystander' mechanism. This MAC-mediated bystander damage initiates NLRP3 inflammasome activation, resulting in caspase-1 activation and IL-1ß and IL-18 secretion. Inflammasome activation is not induced when macrophages phagocytize unopsonized particles or particles opsonized with serum deficient in one of the terminal complement components. The secretion of IL-1ß and IL-18 by macrophages depends on NLRP3, ASC (also known as PYCARD) and caspase-1, as macrophages deficient in any one of these components fail to secrete these cytokines following phagocytosis. The phagocytosis of complement-opsonized particles increases leukocyte recruitment and promotes T helper 17 cell (TH17) biasing. These findings reveal a new mechanism by which complement promotes inflammation and regulates innate and adaptive immunity.

Simultaneous transcriptional profiling of Leishmania major and its murine macrophage host cell reveals insights into host-pathogen interactions.

BACKGROUND: Parasites of the genus Leishmania are the causative agents of leishmaniasis, a group of diseases that range in manifestations from skin lesions to fatal visceral disease. The life cycle of Leishmania parasites is split between its insect vector and its mammalian host, where it resides primarily inside of macrophages. Once intracellular, Leishmania parasites must evade or deactivate the host's innate and adaptive immune responses in order to survive and replicate. RESULTS: We performed transcriptome profiling using RNA-seq to simultaneously identify global changes in murine macrophage and L. major gene expression as the parasite entered and persisted within murine macrophages during the first 72 h of an infection. Differential gene expression, pathway, and gene ontology analyses enabled us to identify modulations in host and parasite responses during an infection. The most substantial and dynamic gene expression responses by both macrophage and parasite were observed during early infection. Murine genes related to both pro- and anti-inflammatory immune responses and glycolysis were substantially upregulated and genes related to lipid metabolism, biogenesis, and Fc gamma receptor-mediated phagocytosis were downregulated. Upregulated parasite genes included those aimed at mitigating the effects of an oxidative response by the host immune system while downregulated genes were related to translation, cell signaling, fatty acid biosynthesis, and flagellum structure. CONCLUSIONS: The gene expression patterns identified in this work yield signatures that characterize multiple developmental stages of L. major parasites and the coordinated response of Leishmania-infected macrophages in the real-time setting of a dual biological system. This comprehensive dataset offers a clearer and more sensitive picture of the interplay between host and parasite during intracellular infection, providing additional insights into how pathogens are able to evade host defenses and modulate the biological functions of the cell in order to survive in the mammalian environment.

The generation of macrophages with anti-inflammatory activity in the absence of STAT6 signaling.

Macrophages readily change their phenotype in response to exogenous stimuli. In this work, macrophages were stimulated under a variety of experimental conditions, and phenotypic alterations were correlated with changes in gene expression. We identified 3 transcriptionally related populations of macrophages with immunoregulatory activity. They were generated by stimulating cells with TLR ligands in the presence of 3 different "reprogramming" signals: high-density ICs, PGE2, or Ado. All 3 of these cell populations produced high levels of transcripts for IL-10 and growth and angiogenic factors. They also secreted reduced levels of inflammatory cytokines IL-1ß, IL-6, and IL-12. All 3 macrophage phenotypes could partially rescue mice from lethal endotoxemia, and therefore, we consider each to have anti-inflammatory activity. This ability to regulate innate-immune responses occurred equally well in macrophages from STAT6-deficient mice. The lack of STAT6 did not affect the ability of macrophages to change cytokine production reciprocally or to rescue mice from lethal endotoxemia. Furthermore, treatment of macrophages with IL-4 failed to induce similar phenotypic or transcriptional alterations. This work demonstrates that there are multiple ways to generate macrophages with immunoregulatory activity. These anti-inflammatory macrophages are transcriptionally and functionally related to each other and are quite distinct from macrophages treated with IL-4.

Advanced cardiac amyloidosis associated with normal interventricular septal thickness: an uncommon presentation of infiltrative cardiomyopathy.

BACKGROUND: Increased interventricular septal (IVS) thickness on echocardiography is a diagnostic criterion for cardiac amyloidosis and classically precedes decrement in left ventricular ejection fraction (LVEF). The investigators describe patients with histologically confirmed cardiac amyloidosis who had significant myocardial dysfunction (LVEF ≤ 40%) despite having normal IVS thickness. METHODS: All patients with systemic amyloidosis and LVEFs ≤ 40% were analyzed to identify the prevalence of normal IVS thickness. Patients with known histories of cardiomyopathy or coronary artery disease were excluded. Histologic evaluation of tissue included assessment of amyloid burden and average myocyte diameter. RESULTS: There were 255 patients with amyloidosis with LVEFs ≤ 40%, of whom seven (3%) had normal IVS thickness and histologic confirmation of cardiac involvement. Of these, six had immunoglobulin light chain amyloidosis, and one had senile amyloidosis. A majority of patients (86%) presented with new-onset cardiac dysfunction associated with edema and/or dyspnea. Electrocardiographic findings included low voltage (43%) and a pseudoinfarct pattern (29%). The 1-year survival from initial tissue diagnosis in the cohort with normal IVS thickness was similar to matched patients with amyloidosis with increased IVS thickness and LVEF ≤ 40% (21% vs 18%, respectively, P = .32). Myocardial tissue amyloid burden and average myocyte diameter were significantly reduced in cases compared with controls. CONCLUSIONS: Cardiac amyloidosis can uncommonly present with normal IVS thickness despite significant myocardial dysfunction. The prognosis of these patients is as poor as those with increased IVS thickness. Amyloidosis should be considered in the differential diagnosis of patients with cardiomyopathy and reduced LVEFs despite normal IVS thickness.