Publications by authors named "Alexander Nelson"

29 Publications

  • Page 1 of 1

Thoracic Sertoli-Leydig cell tumor: An alternative type of pleuropulmonary blastoma associated with DICER1 variation.

Pediatr Blood Cancer 2021 Nov 16;68(11):e29284. Epub 2021 Aug 16.

International PPB/DICER1 Registry, Children's Minnesota, Minneapolis, Minnesota, USA.

A 2-year-old boy presented with a large cystic and solid chest mass arising from the lung, radiographically consistent with pleuropulmonary blastoma (PPB). He underwent right lower lobectomy with resection of a well-circumscribed, mixed solid and cystic mass. The solid areas were composed of cords and nests of tumor cells in the myxoid stroma and retiform foci whose pathologic and immunophenotypic findings were consistent with a sex cord-stromal tumor with features of a Sertoli-Leydig cell tumor. Tumor testing showed a pathogenic variant in the DICER1 RNase IIIb hotspot domain. Family history was suggestive of DICER1 germline pathogenic DICER1 variation in absence of a detectable germline variant. He received 12 cycles of chemotherapy with ifosfamide, vincristine, dactinomycin and doxorubicin (IVADo) and surgery with complete response. One year after completion of chemotherapy, imaging studies showed concern for recurrence confirmed by thorascopic biopsy of a pleural-based mass. He is currently receiving cisplatin-based chemotherapy with reduction in tumor size. Review of the literature showed no similar cases; however, review of our pathology files revealed a single similar case of anterior mediastinal Sertoli cell tumor in a 3-year-old girl.
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http://dx.doi.org/10.1002/pbc.29284DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8463509PMC
November 2021

Cell contact guidance via sensing anisotropy of network mechanical resistance.

Proc Natl Acad Sci U S A 2021 Jul;118(29)

Department of Biomedical Engineering, University of Minnesota, Twin Cities, Minneapolis, MN 55455;

Despite the ubiquitous importance of cell contact guidance, the signal-inducing contact guidance of mammalian cells in an aligned fibril network has defied elucidation. This is due to multiple interdependent signals that an aligned fibril network presents to cells, including, at least, anisotropy of adhesion, porosity, and mechanical resistance. By forming aligned fibrin gels with the same alignment strength, but cross-linked to different extents, the anisotropic mechanical resistance hypothesis of contact guidance was tested for human dermal fibroblasts. The cross-linking was shown to increase the mechanical resistance anisotropy, without detectable change in network microstructure and without change in cell adhesion to the cross-linked fibrin gel. This methodology thus isolated anisotropic mechanical resistance as a variable for fixed anisotropy of adhesion and porosity. The mechanical resistance anisotropy |*| - |*| increased over fourfold in terms of the Fourier magnitudes of microbead displacement |*| and |*| at the drive frequency with respect to alignment direction obtained by optical forces in active microrheology. Cells were found to exhibit stronger contact guidance in the cross-linked gels possessing greater mechanical resistance anisotropy: the cell anisotropy index based on the tensor of cell orientation, which has a range 0 to 1, increased by 18% with the fourfold increase in mechanical resistance anisotropy. We also show that modulation of adhesion via function-blocking antibodies can modulate the guidance response, suggesting a concomitant role of cell adhesion. These results indicate that fibroblasts can exhibit contact guidance in aligned fibril networks by sensing anisotropy of network mechanical resistance.
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http://dx.doi.org/10.1073/pnas.2024942118DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8307272PMC
July 2021

A protocol for representative sampling of solid tumors to improve the accuracy of sequencing results.

STAR Protoc 2021 Sep 26;2(3):100624. Epub 2021 Jun 26.

Royal Marsden NHS Foundation Trust, London, UK.

Owing to spatial segregation of tumor subclones, solid tumor sampling using formalin-fixed, paraffin-embedded blocks is often inadequate to represent the genomic heterogeneity of solid tumors. We present an approach, representative sampling, to dissect and homogenize leftover residual surgical tissue prior to sequencing. We also detail optional tumor cell enrichment and DNA preparation. This method, applicable only to surgically removed tumors with leftover tissue, facilitates robust sampling to avoid missing or over-representing actionable variants. For complete details on the use and execution of this protocol, please refer to Litchfield et al. (2020).
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http://dx.doi.org/10.1016/j.xpro.2021.100624DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8243513PMC
September 2021

Soluble MD-2 and Heme in Sickle Cell Disease Plasma Promote Pro-Inflammatory Signaling in Endothelial Cells.

Front Immunol 2021 26;12:632709. Epub 2021 Mar 26.

Division of Hematology, Oncology and Transplantation, Department of Medicine, University of Minnesota, Minneapolis, MN, United States.

Recent evidence indicates that hemolysis in sickle cell disease (SCD) promotes inflammation innate immune signaling through toll-like receptor 4 (TLR4). Free heme released by hemolyzed red blood cells can bind to myeloid differentiation factor-2 (MD-2) and activate TLR4 pro-inflammatory signaling on endothelium to promote vaso-occlusion and acute chest syndrome in murine models of SCD. MD-2 is co-expressed with TLR4 on cell membranes, but in inflammatory conditions, soluble MD-2 (sMD-2) is elevated in plasma. sMD-2 levels were significantly increased in human and murine sickle (SS) plasma as compared to normal (AA) plasma. Human umbilical vein endothelial cells (HUVEC) and human lung microvascular endothelial cells incubated with human SS plasma had significant increases in pro-inflammatory IL-8, IL-6, and soluble VCAM-1 secretion compared to endothelial cells incubated with AA plasma. The increase in HUVEC IL-8 secretion was blocked by depletion of sMD-2 from SS plasma and enhanced by the addition of sMD-2 to AA plasma. The TLR4 signaling inhibitor, TAK-242, inhibited HUVEC IL-8 secretion in response to SS plasma by 85%. Heme-agarose pull-down assays and UV/Vis spectroscopy demonstrated that heme binds to sMD-2. Hemopexin, a high affinity heme-binding protein, inhibited HUVEC IL-8 secretion induced by SS plasma or SS and AA plasma supplemented with sMD-2. These data suggest that sMD-2 bound to heme might play an important role in pro-inflammatory signaling by endothelium in SCD.
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http://dx.doi.org/10.3389/fimmu.2021.632709DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8033004PMC
September 2021

Human CD36 monocytes induce Foxp3  CD25 T cells with regulatory functions from CD4 and CD8 subsets.

Immunology 2021 07 7;163(3):293-309. Epub 2021 Mar 7.

Department of Microbiology and Immunology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL, USA.

The fetal and neonatal immune systems are uniquely poised to generate tolerance to self, maternal and environmental antigens encountered in the womb and shortly after birth. However, the tolerogenic nature of fetal and neonatal immunity can be detrimental in the context of pathogens, leading to overwhelming bacterial infections or chronic viral infections. A variety of mechanisms contribute to fetal and neonatal tolerance, including a propensity to generate Foxp3 regulatory T cells (Treg cells). However, the mechanism(s) of fetal Foxp3 T-cell differentiation, the specific antigen-presenting cells required and factors that inhibit Treg generation after the neonatal period are poorly understood. Here, we demonstrate that a subset of CD14 monocytes expressing the scavenger molecule, CD36, can generate CD4 and CD8 T cells that coexpress Foxp3 and T-bet from both umbilical cord blood. These Foxp3 T-bet T cells potently suppress T-cell proliferation and ameliorate xenogeneic graft-versus-host disease. CD14 CD36 monocytes provide known Treg-inducing signals: membrane-bound transforming growth factor-beta and retinoic acid. Unexpectedly, adult peripheral blood monocytes are also capable of inducing Foxp3 T cells from both cord blood and adult peripheral naïve T cells. The induction of Foxp3 T cells in umbilical cord blood by monocytes was inhibited by the lymphoid fraction of adult peripheral blood cells. These studies highlight a novel immunoregulatory role of monocytes and suggest that antigen presentation by CD36 monocytes may contribute to the peripheral development of Foxp3 T-bet T cells with regulatory functions in both neonates and adults.
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http://dx.doi.org/10.1111/imm.13316DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8207412PMC
July 2021

Lipid mediators and biomarkers associated with type 1 diabetes development.

JCI Insight 2020 08 20;5(16). Epub 2020 Aug 20.

Department of Cell, Developmental, and Integrative Biology, and.

Type 1 diabetes (T1D) is a consequence of autoimmune β cell destruction, but the role of lipids in this process is unknown. We previously reported that activation of Ca2+-independent phospholipase A2β (iPLA2β) modulates polarization of macrophages (MΦ). Hydrolysis of the sn-2 substituent of glycerophospholipids by iPLA2β can lead to the generation of oxidized lipids (eicosanoids), pro- and antiinflammatory, which can initiate and amplify immune responses triggering β cell death. As MΦ are early triggers of immune responses in islets, we examined the impact of iPLA2β-derived lipids (iDLs) in spontaneous-T1D prone nonobese diabetic mice (NOD), in the context of MΦ production and plasma abundances of eicosanoids and sphingolipids. We find that (a) MΦNOD exhibit a proinflammatory lipid landscape during the prediabetic phase; (b) early inhibition or genetic reduction of iPLA2β reduces production of select proinflammatory lipids, promotes antiinflammatory MΦ phenotype, and reduces T1D incidence; (c) such lipid changes are reflected in NOD plasma during the prediabetic phase and at T1D onset; and (d) importantly, similar lipid signatures are evidenced in plasma of human subjects at high risk for developing T1D. These findings suggest that iDLs contribute to T1D onset and identify select lipids that could be targeted for therapeutics and, in conjunction with autoantibodies, serve as early biomarkers of pre-T1D.
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http://dx.doi.org/10.1172/jci.insight.138034DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7455134PMC
August 2020

Pleuropulmonary blastoma-like peritoneal sarcoma: a newly described malignancy associated with biallelic DICER1 pathogenic variation.

Mod Pathol 2020 10 15;33(10):1922-1929. Epub 2020 May 15.

International Pleuropulmonary Blastoma/DICER1 Registry, Children's Minnesota, Minneapolis, MN, USA.

Since the original description of pathogenic germline DICER1 variation underlying pleuropulmonary blastoma (PPB), the spectrum of extrapulmonary neoplasms known to be associated with DICER1 has continued to expand and now includes tumors of the ovary, thyroid, kidney, eye, and brain among other sites. This report documents our experience with another manifestation: a primitive sarcoma that resembles PPB and DICER1-associated sarcoma of the kidney. These tumors are distinguished by their unusual location in the peritoneal cavity, associated with visceral and/or parietal mesothelium. A total of seven cases were identified through pathology review in children presenting at a median age of 13 years (range 3-14 years). Primary sites of origin included the fallopian tube (four cases), serosal surface of the colon (one case), and pelvic sidewall (two cases). One case had pathologic features of type I PPB, another type Ir (regressed) PPB, and the remaining five had features of type II or III PPB with a mixed primitive sarcomatous pattern with or without cystic elements. All had a pathogenic DICER1 variation identified in germline and/or tumor DNA. PPB-like peritoneal tumors represent a newly described manifestation of DICER1 pathogenic variation whose pathologic features are also recapitulated in DICER1-related renal sarcoma, cervical embryonal rhabdomyosarcoma, and some Sertoli-Leydig cell tumors with heterologous elements. Tumors arising from the fallopian tube or elsewhere in the abdomen/pelvis, especially those with heterogeneous rhabdomyosarcomatous and/or cartilaginous differentiation, should prompt consideration of germline and tumor DICER1 testing.
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http://dx.doi.org/10.1038/s41379-020-0558-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7529703PMC
October 2020

Representative Sequencing: Unbiased Sampling of Solid Tumor Tissue.

Cell Rep 2020 05;31(5):107550

Renal and Skin Units, The Royal Marsden Hospital, London SW3 6JJ, UK.

Although thousands of solid tumors have been sequenced to date, a fundamental under-sampling bias is inherent in current methodologies. This is caused by a tissue sample input of fixed dimensions (e.g., 6 mm biopsy), which becomes grossly under-powered as tumor volume scales. Here, we demonstrate representative sequencing (Rep-Seq) as a new method to achieve unbiased tumor tissue sampling. Rep-Seq uses fixed residual tumor material, which is homogenized and subjected to next-generation sequencing. Analysis of intratumor tumor mutation burden (TMB) variability shows a high level of misclassification using current single-biopsy methods, with 20% of lung and 52% of bladder tumors having at least one biopsy with high TMB but low clonal TMB overall. Misclassification rates by contrast are reduced to 2% (lung) and 4% (bladder) when a more representative sampling methodology is used. Rep-Seq offers an improved sampling protocol for tumor profiling, with significant potential for improved clinical utility and more accurate deconvolution of clonal structure.
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http://dx.doi.org/10.1016/j.celrep.2020.107550DOI Listing
May 2020

Improved protein structure prediction using potentials from deep learning.

Nature 2020 01 15;577(7792):706-710. Epub 2020 Jan 15.

DeepMind, London, UK.

Protein structure prediction can be used to determine the three-dimensional shape of a protein from its amino acid sequence. This problem is of fundamental importance as the structure of a protein largely determines its function; however, protein structures can be difficult to determine experimentally. Considerable progress has recently been made by leveraging genetic information. It is possible to infer which amino acid residues are in contact by analysing covariation in homologous sequences, which aids in the prediction of protein structures. Here we show that we can train a neural network to make accurate predictions of the distances between pairs of residues, which convey more information about the structure than contact predictions. Using this information, we construct a potential of mean force that can accurately describe the shape of a protein. We find that the resulting potential can be optimized by a simple gradient descent algorithm to generate structures without complex sampling procedures. The resulting system, named AlphaFold, achieves high accuracy, even for sequences with fewer homologous sequences. In the recent Critical Assessment of Protein Structure Prediction (CASP13)-a blind assessment of the state of the field-AlphaFold created high-accuracy structures (with template modelling (TM) scores of 0.7 or higher) for 24 out of 43 free modelling domains, whereas the next best method, which used sampling and contact information, achieved such accuracy for only 14 out of 43 domains. AlphaFold represents a considerable advance in protein-structure prediction. We expect this increased accuracy to enable insights into the function and malfunction of proteins, especially in cases for which no structures for homologous proteins have been experimentally determined.
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http://dx.doi.org/10.1038/s41586-019-1923-7DOI Listing
January 2020

Macrophage polarization is linked to Ca-independent phospholipase Aβ-derived lipids and cross-cell signaling in mice.

J Lipid Res 2020 02 9;61(2):143-158. Epub 2019 Dec 9.

Department of Cell, Developmental, and Integrative Biology University of Alabama at Birmingham, Birmingham, AL 35294

Phospholipases A (PLAs) catalyze hydrolysis of the -2 substituent from glycerophospholipids to yield a free fatty acid (i.e., arachidonic acid), which can be metabolized to pro- or anti-inflammatory eicosanoids. Macrophages modulate inflammatory responses and are affected by Ca-independent phospholipase A (PLA)β (iPLAβ). Here, we assessed the link between iPLAβ-derived lipids (iDLs) and macrophage polarization. Macrophages from WT and KO () mice were classically M1 pro-inflammatory phenotype activated or alternatively M2 anti-inflammatory phenotype activated, and eicosanoid production was determined by ultra-performance LC ESI-MS/MS. As a genotypic control, we performed similar analyses on macrophages from mice with selective iPLAβ overexpression in β-cells. Compared with WT, generation of select pro-inflammatory prostaglandins (PGs) was lower in , and that of a specialized pro-resolving lipid mediator (SPM), resolvin D2, was higher; both changes are consistent with the M2 phenotype. Conversely, macrophages from mice exhibited an opposite landscape, one associated with the M1 phenotype: namely, increased production of pro-inflammatory eicosanoids (6-keto PGFα, PGE, leukotriene B) and decreased ability to generate resolvin D2. These changes were not linked with secretory PLA or cytosolic PLAα or with leakage of the transgene. Thus, we report previously unidentified links between select iPLAβ-derived eicosanoids, an SPM, and macrophage polarization. Importantly, our findings reveal for the first time that β-cell iPLAβ-derived signaling can predispose macrophage responses. These findings suggest that iDLs play critical roles in macrophage polarization, and we posit that they could be targeted therapeutically to counter inflammation-based disorders.
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http://dx.doi.org/10.1194/jlr.RA119000281DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6997598PMC
February 2020

Protein structure prediction using multiple deep neural networks in the 13th Critical Assessment of Protein Structure Prediction (CASP13).

Proteins 2019 12;87(12):1141-1148

DeepMind, London, UK.

We describe AlphaFold, the protein structure prediction system that was entered by the group A7D in CASP13. Submissions were made by three free-modeling (FM) methods which combine the predictions of three neural networks. All three systems were guided by predictions of distances between pairs of residues produced by a neural network. Two systems assembled fragments produced by a generative neural network, one using scores from a network trained to regress GDT_TS. The third system shows that simple gradient descent on a properly constructed potential is able to perform on par with more expensive traditional search techniques and without requiring domain segmentation. In the CASP13 FM assessors' ranking by summed z-scores, this system scored highest with 68.3 vs 48.2 for the next closest group (an average GDT_TS of 61.4). The system produced high-accuracy structures (with GDT_TS scores of 70 or higher) for 11 out of 43 FM domains. Despite not explicitly using template information, the results in the template category were comparable to the best performing template-based methods.
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http://dx.doi.org/10.1002/prot.25834DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7079254PMC
December 2019

Replication of Smart-City, Internet of Things Assets in a Municipal Deployment.

IEEE Internet Things J 2019 ;6

National Institute of Standards and Technology, U.S. Department of Commerce, 100 Bureau Drive, Gaithersburg, MD, USA.

Recent efforts to integrate Internet Of Things (IoT) technologies into Smart City constructs have proven successful through proof-of-concept deployments in multiple cities. To facilitate additional deployments, standardization and dissemination of best practices for these technologies is critical. To that effort, this work seeks to establish a framework in a set of IoT hardware, software, and wireless radio components that are flexible to address several use cases and easily replicable to new deployments. Moreover, the framework aims to be standards-based and to use best practices for cybersecurity to maintain security and privacy. The framework is developed, deployed, and tested through three sub-projects in different domains and a live testbed housed by a municipal government, collecting over 160 million distinct sensor records from eight physical locations over a period of 8 months. Additionally, the framework is replicated to a separate jurisdiction to prove ease of replicability. This work identifies common barriers to IoT adoption and replication, both technological and organizational, and enumerates the approaches that were taken to overcome those barriers in these projects.
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http://dx.doi.org/10.1109/JIOT.2019.2911010DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6774360PMC
January 2019

Evaluating touchless capacitive gesture recognition as an assistive device for upper extremity mobility impairment.

J Rehabil Assist Technol Eng 2018 Jan-Dec;5:2055668318762063. Epub 2018 May 16.

Department of Physical Therapy and Rehabilitation Science, University of Maryland, School of Medicine, Baltimore, MD, USA.

Introduction: This paper explores the feasibility of using touchless textile sensors as an input to environmental control for individuals with upper-extremity mobility impairments. These sensors are capacitive textile sensors embedded into clothing and act as proximity sensors.

Methods: We present results from five individuals with spinal cord injury as they perform gestures that mimic an alphanumeric gesture set. The gestures are used for controlling appliances in a home setting. Our setup included a custom visualization that provides feedback to the individual on how the system is tracking the movement and the type of gesture being recognized. Our study included a two-stage session at a medical school with five subjects with upper extremity mobility impairment.

Results: The experimenting sessions derived binary gesture classification accuracies greater than 90% on average. The sessions also revealed intricate details in participant's motions, from which we draw two key insights on the design of the wearable sensor system.

Conclusion: First, we provide evidence that is a critical ingredient to the success of wearable sensing in this population group. The sensor hardware, the gesture set, and the underlying gesture recognition algorithm must be personalized to the individual's need and injury level. Secondly, we show that explicit feedback to the user is useful when the user is being trained on the system. Moreover, being able to see the end goal of controlling appliances using the system is a key motivation to properly learn gestures.
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http://dx.doi.org/10.1177/2055668318762063DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6453073PMC
May 2018

iPLAβ and its role in male fertility, neurological disorders, metabolic disorders, and inflammation.

Biochim Biophys Acta Mol Cell Biol Lipids 2019 06 5;1864(6):846-860. Epub 2018 Nov 5.

Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, United States of America; Comprehensive Diabetes Center, University of Alabama at Birmingham, Birmingham, AL, United States of America. Electronic address:

The Ca-independent phospholipases, designated as group VI iPLAs, also referred to as PNPLAs due to their shared homology with patatin, include the β, γ, δ, ε, ζ, and η forms of the enzyme. The iPLAs are ubiquitously expressed, share a consensus GXSXG catalytic motif, and exhibit organelle/cell-specific localization. Among the iPLAs, iPLAβ has received wide attention as it is recognized to be involved in membrane remodeling, cell proliferation, cell death, and signal transduction. Ongoing studies implicate participation of iPLAβ in a variety of disease processes including cancer, cardiovascular abnormalities, glaucoma, and peridonditis. This review will focus on iPLAβ and its links to male fertility, neurological disorders, metabolic disorders, and inflammation.
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http://dx.doi.org/10.1016/j.bbalip.2018.10.010DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6432790PMC
June 2019

Activated human Foxp3 regulatory T cells produce membrane-bound TNF.

Cytokine 2018 11 6;111:454-459. Epub 2018 Jun 6.

Institute of Infectious Disease and Immunology, Stritch School of Medicine, Loyola University Chicago, USA; Department of Microbiology and Immunology, Stritch School of Medicine, Loyola University Chicago, USA; Van Kampen Cardiopulmonary Research Laboratory, Stritch School of Medicine, Loyola University Chicago, USA. Electronic address:

TNF is a multifunctional cytokine that is critical to host defense against pathogens but can also drive the pathophysiology of inflammatory diseases. Inhibition of TNF occasionally causes exacerbation of some autoimmune diseases, suggesting a role for TNF in the regulation of immune homeostasis. Here, we demonstrate that human peripheral blood CD4CD25Foxp3 regulatory T cells (Tregs) express membrane-bound TNF, a potent activator of the type 2 TNF receptor. While the type 1 TNF receptor can cause cell death and is expressed ubiquitously, the type 2 receptor promotes cell growth and its expression is limited mainly to immune and endothelial cells. When autocrine TNF is blocked in an in vitro culture without IL-2, activated Tregs stop proliferating. These data indicate a novel role for TNF as a Treg-derived autocrine growth factor.
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http://dx.doi.org/10.1016/j.cyto.2018.05.036DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6281785PMC
November 2018

Tracking Cancer Evolution Reveals Constrained Routes to Metastases: TRACERx Renal.

Cell 2018 04 12;173(3):581-594.e12. Epub 2018 Apr 12.

Department of Pathology, University College London Hospitals, London WC1E 6DE, UK.

Clear-cell renal cell carcinoma (ccRCC) exhibits a broad range of metastatic phenotypes that have not been systematically studied to date. Here, we analyzed 575 primary and 335 metastatic biopsies across 100 patients with metastatic ccRCC, including two cases sampledat post-mortem. Metastatic competence was afforded by chromosome complexity, and we identify 9p loss as a highly selected event driving metastasis and ccRCC-related mortality (p = 0.0014). Distinct patterns of metastatic dissemination were observed, including rapid progression to multiple tissue sites seeded by primary tumors of monoclonal structure. By contrast, we observed attenuated progression in cases characterized by high primary tumor heterogeneity, with metastatic competence acquired gradually and initial progression to solitary metastasis. Finally, we observed early divergence of primitive ancestral clones and protracted latency of up to two decades as a feature of pancreatic metastases.
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http://dx.doi.org/10.1016/j.cell.2018.03.057DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5938365PMC
April 2018

Cell intrinsic characteristics of human cord blood naïve CD4T cells.

Immunol Lett 2018 01 24;193:51-57. Epub 2017 Nov 24.

Department of Microbiology and Immunology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL 60153, United States; Institute of Infectious Disease and Immunology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL 60153, United States; Van Kampen Cardiopulmonary Research Laboratory, Stritch School of Medicine, Loyola University Chicago, Maywood, IL 60153, United States. Electronic address:

It has been generally considered that the perinatal immune system is less inflammatory compared to the adult system and type 2 responses predominate perinatal immune responses against antigens. Indeed, previous studies in mice showed that there are cell-intrinsic differences between neonatal and adult CD4T cells. However, studies on human cord blood and infant blood demonstrated that human perinatal T cells do not produce elevated levels of Th2 cytokines with the exception of IL-13. These data raise the question if human T cells in the perinatal blood fundamentally differ from adult T cells. To decipher differences between human perinatal and adult T cells, we performed a focused comparative analysis on purified naïve CD4T cells from umbilical cord blood (UCB) and adult peripheral blood. Our data demonstrate naïve CD4T cells from UCB differ from adult naïve CD4T cells in surface expression of CD26, dipeptidyl peptidase-4. While only a fraction of effector/memory T cells from adult blood express CD26, practically all T cells from UCB express high levels of CD26. We also determined that Th1/Th2 polarizing conditions induce UCB CD4T cells to produce higher levels of IFN-γ and IL-5 compared to adult CD4T cells, respectively. These data demonstrate intrinsic differences between UCB and adult naive CD4T cells and suggest that human perinatal immune responses involve more complex mechanisms than the previously thought Th2-dominant responses.
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http://dx.doi.org/10.1016/j.imlet.2017.11.011DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5751702PMC
January 2018

Integrating end-user feedback in the concept stage of development of a novel sensor access system for environmental control.

Disabil Rehabil Assist Technol 2018 05 19;13(4):366-372. Epub 2017 May 19.

b Department of Computer Science and Electrical Engineering , University of Maryland , Baltimore , MD , USA.

Purpose: This article illustrates user-centred design of a novel sensor access system for environmental control in the concept stage of development.

Methods: Focus groups of individuals with disabilities and rehabilitation healthcare professionals were provided with video illustration of the technology and asked to provide quantitative and qualitative feedback through a semistructured interview process. Qualitative methods were employed to analyse transcribed comments to develop themes supporting ongoing development of the technology.

Results: Both end-user streams rated the original design features of the sensor access system (alternative interface to assistive technologies, having wireless capabilities and not requiring batteries) as having high potential value. Both groups identified a need for the future design of the sensor technology to be able to capture minimal/reduced movements for those with severe physical impairments. Themes included (1) the sensor technology could be individualized/customized to accommodate the user, (2) minimal positioning and set-up requirement and (3) technology that alleviated problems encountered with touch-based solutions.

Conclusions: Inclusion of end-user feedback provided the research team with valuable information that supported the initial conceptualization of the design features of the technology and provided valuable data to support development of a new prototype that can capture more reduced/minimal movements. Implication for Rehabilitation User-centered design of assistive technology is essential to the development of technology that can meet the unique needs of those with the most severe physical impairments. New sensor technology may alleviate some of the access challenges faced by individuals with severe physical impairments. Collaboration between all key stakeholders (individuals with disabilities, rehabilitation professionals, researchers, and developers) is an essential component in the iterative assistive technology design process.
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http://dx.doi.org/10.1080/17483107.2017.1328615DOI Listing
May 2018

Polarization of Macrophages toward M2 Phenotype Is Favored by Reduction in iPLA2β (Group VIA Phospholipase A2).

J Biol Chem 2016 10 20;291(44):23268-23281. Epub 2016 Sep 20.

Department of Cell, Developmental, and Integrative Biology,

Macrophages are important in innate and adaptive immunity. Macrophage participation in inflammation or tissue repair is directed by various extracellular signals and mediated by multiple intracellular pathways. Activation of group VIA phospholipase A (iPLAβ) causes accumulation of arachidonic acid, lysophospholipids, and eicosanoids that can promote inflammation and pathologic states. We examined the role of iPLAβ in peritoneal macrophage immune function by comparing wild type (WT) and iPLAβ mouse macrophages. Compared with WT, iPLAβ macrophages exhibited reduced proinflammatory M1 markers when classically activated. In contrast, anti-inflammatory M2 markers were elevated under naïve conditions and induced to higher levels by alternative activation in iPLAβ macrophages compared with WT. Induction of eicosanoid (12-lipoxygenase (12-LO) and cyclooxygenase 2 (COX2))- and reactive oxygen species (NADPH oxidase 4 (NOX4))-generating enzymes by classical activation pathways was also blunted in iPLAβ macrophages compared with WT. The effects of inhibitors of iPLAβ, COX2, or 12-LO to reduce M1 polarization were greater than those to enhance M2 polarization. Certain lipids (lysophosphatidylcholine, lysophosphatidic acid, and prostaglandin E) recapitulated M1 phenotype in iPLAβ macrophages, but none tested promoted M2 phenotype. These findings suggest that (a) lipids generated by iPLAβ and subsequently oxidized by cyclooxygenase and 12-LO favor macrophage inflammatory M1 polarization, and (b) the absence of iPLAβ promotes macrophage M2 polarization. Reducing macrophage iPLAβ activity and thereby attenuating macrophage M1 polarization might cause a shift from an inflammatory to a recovery/repair milieu.
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http://dx.doi.org/10.1074/jbc.M116.754945DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5087743PMC
October 2016

Subclinical cardiopulmonary dysfunction in stage 3 chronic kidney disease.

Open Heart 2016;3(1):e000370. Epub 2016 Feb 24.

William Harvey Research Institute, Queen Mary University of London , London , UK.

Objective: Reduced exercise capacity is well documented in end-stage chronic kidney disease (CKD), preceded by changes in cardiac morphology in CKD stage 3. However, it is unknown whether subclinical cardiopulmonary dysfunction occurs in CKD stage 3 independently of heart failure.

Methods: Prospective observational cross-sectional study of exercise capacity assessed by cardiopulmonary exercise testing in 993 preoperative patients. Primary outcome was peak oxygen consumption (VO2peak). Anaerobic threshold (AT), oxygen pulse and exercise-evoked measures of autonomic function were analysed, controlling for CKD stage 3, age, gender, diabetes mellitus and hypertension.

Results: CKD stage 3 was present in 93/993 (9.97%) patients. Diabetes mellitus (RR 2.49 (95% CI 1.59 to 3.89); p<0.001), and hypertension (RR 3.20 (95% CI 2.04 to 5.03); p<0.001)) were more common in CKD stage 3. Cardiac failure (RR 0.83 (95% CI 0.30 to 2.24); p=0.70) and ischaemic heart disease (RR 1.40 (95% CI 0.97 to 2.02); p=0.09) were not more common in CKD stage 3. Patients with CKD stage 3 had lower predicted VO2peak (mean difference: 6% (95% CI 1% to 11%); p=0.02), lower peak heart rate (mean difference:9 bpm (95% CI 3 to 14); p=0.03)), lower AT (mean difference: 1.1 mL/min/kg (95% CI 0.4 to 1.7); p<0.001) and impaired heart rate recovery (mean difference: 4 bpm (95% CI 1 to 7); p<0.001)).

Conclusions: Subclinical cardiopulmonary dysfunction in CKD stage 3 is common. This study suggests that maladaptive cardiovascular/autonomic dysfunction may be established in CKD stage 3, preceding pathophysiology reported in end-stage CKD.
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http://dx.doi.org/10.1136/openhrt-2015-000370DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4847133PMC
February 2016

Sympathetic autonomic dysfunction and impaired cardiovascular performance in higher risk surgical patients: implications for perioperative sympatholysis.

Open Heart 2015;2(1):e000268. Epub 2015 Oct 19.

Division of Medicine, Department of Clinical Physiology , University College London , London , UK ; Department of Neuroscience, Physiology and Pharmacology , Centre for Cardiovascular and Metabolic Neuroscience, University College London , London , UK ; William Harvey Research Institute, Queen Mary University of London, London, UK.

Objective: Recent perioperative trials have highlighted the urgent need for a better understanding of why sympatholytic drugs intended to reduce myocardial injury are paradoxically associated with harm (stroke, myocardial infarction). We hypothesised that following a standardised autonomic challenge, a subset of patients may demonstrate excessive sympathetic activation which is associated with exercise-induced ischaemia and impaired cardiac output.

Methods: Heart rate rise during unloaded pedalling (zero workload) prior to the onset of cardiopulmonary exercise testing (CPET) was measured in 2 observation cohorts of elective surgical patients. The primary outcome was exercise-evoked, ECG-defined ischaemia (>1 mm depression; lead II) associated with an exaggerated increase in heart rate (EHRR ≥12 bpm based on prognostic data for all-cause cardiac death in preceding epidemiological studies). Secondary outcomes included cardiopulmonary performance (oxygen pulse (surrogate for left ventricular stroke volume), peak oxygen consumption (VO2peak), anaerobic threshold (AT)) and perioperative heart rate.

Results: EHRR was present in 40.4-42.7% in both centres (n=232, n=586 patients). Patients with EHRR had higher heart rates perioperatively (p<0.05). Significant ST segment depression during CPET was more common in EHRR patients (relative risk 1.7 (95% CI 1.3 to 2.1); p<0.001). EHRR was associated with 11% (95%CI 7% to 15%) lower predicted oxygen pulse (p<0.0001), consistent with impaired left ventricular function.

Conclusions: EHRR is common and associated with ECG-defined ischaemia and impaired cardiac performance. Perioperative sympatholysis may further detrimentally affect cardiac output in patients with this phenotype.
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http://dx.doi.org/10.1136/openhrt-2015-000268DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4620232PMC
October 2015

Gelsolin-like activation of villin: calcium sensitivity of the long helix in domain 6.

Biochemistry 2013 Nov 29;52(45):7890-900. Epub 2013 Oct 29.

Department of Chemistry, Western Washington University , 516 High Street, Bellingham, Washington 98225-9150, United States.

Villin is a gelsolin-like cytoskeleton regulator localized in the brush border at the apical end of epithelial cells. Villin regulates microvilli by bundling F-actin at low calcium levels and severing it at high calcium levels. The villin polypeptide consists of six gelsolin-like repeats (V1-V6) and the unique, actin binding C-terminal headpiece domain (HP). Villin modular fragment V6-HP requires calcium to stay monomeric and bundle F-actin. Our data show that isolated V6 is monomeric and does not bind F-actin at any level of calcium. We propose that the 40-residue unfolded V6-to-HP linker can be a key regulatory element in villin's functions such as its interactions with F-actin. Here we report a calcium-bound solution nuclear magnetic resonance (NMR) structure of V6, which has a gelsolin-like fold with the long α-helix in the extended conformation. Intrinsic tryptophan fluorescence quenching reveals two-Kd calcium binding in V6 (Kd1 of 22 μM and Kd2 of 2.8 mM). According to our NMR data, the conformation of V6 responds the most to micromolar calcium. We show that the long α-helix and the adjacent residues form the calcium-sensitive elements in V6. These observations are consistent with the calcium activation of F-actin severing by villin analogous to the gelsolin helix-straightening mechanism.
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http://dx.doi.org/10.1021/bi400699sDOI Listing
November 2013

Protrusion of a Virtual Model Lamellipodium by Actin Polymerization: A Coarse-grained Langevin Dynamics Model.

J Stat Phys 2008 Oct;133(1):79-100

Department of Chemical Engineering, Vanderbilt University, Nashville, Tennessee 37235.

We report the development of a coarse-grained Langevin dynamics model of a lamellipodium featuring growing F-actin filaments in order to study the effect of stiffness of the F-actin filament, the G-actin monomer concentration, and the number of polymerization sites on lamellipodium protrusion. The virtual lamellipodium is modeled as a low-aspect-ratio doubly capped cylinder formed by triangulated particles on its surface. It is assumed that F-actin filaments are firmly attached to a lamellipodium surface where polymerization sites are located, and actin polymerization takes place by connecting a G-actin particle to a polymerization site and to the first particle of a growing F-actin filament. It is found that there is an optimal number of polymerization sites for rapid lamellipodium protrusion. The maximum speed of lamellipodium protrusion is related to competition between the number of polymerization sites and the number of available G-actin particles, and the degree of pulling and holding of the lamellipodium surface by non-polymerizing actin filaments. The lamellipodium protrusion by actin polymerization displays saltatory motion exhibiting pseudo-thermal equilibrium: the lamellipodium speed distribution is Maxwellian in two dimensions but the lamellipodium motion is biased so that the lamellipodium speed in the direction of the lamellipodium motion is much larger than that normal to the lamellipodium motion.
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http://dx.doi.org/10.1007/s10955-008-9600-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2846375PMC
October 2008

Extracellular matrix rigidity promotes invadopodia activity.

Curr Biol 2008 Sep 21;18(17):1295-1299. Epub 2008 Aug 21.

Department of Cancer Biology, Vanderbilt University, Nashville, TN 37232, USA.

Invadopodia are actin-rich subcellular protrusions with associated proteases used by cancer cells to degrade extracellular matrix (ECM) [1]. Molecular components of invadopodia include branched actin-assembly proteins, membrane trafficking proteins, signaling proteins, and transmembrane proteinases [1]. Similar structures exist in nontransformed cells, such as osteoclasts and dendritic cells, but are generally called podosomes and are thought to be more involved in cell-matrix adhesion than invadopodia [2-4]. Despite intimate contact with their ECM substrates, it is unknown whether physical or chemical ECM signals regulate invadopodia function. Here, we report that ECM rigidity directly increases both the number and activity of invadopodia. Transduction of ECM-rigidity signals depends on the cellular contractile apparatus [5-7], given that inhibition of nonmuscle myosin II, myosin light chain kinase, and Rho kinase all abrogate invadopodia-associated ECM degradation. Whereas myosin IIA, IIB, and phosphorylated myosin light chain do not localize to invadopodia puncta, active phosphorylated forms of the mechanosensing proteins p130Cas (Cas) and focal adhesion kinase (FAK) are present in actively degrading invadopodia, and the levels of phospho-Cas and phospho-FAK in invadopodia are sensitive to myosin inhibitors. Overexpression of Cas or FAK further enhances invadopodia activity in cells plated on rigid polyacrylamide substrates. Thus, in invasive cells, ECM-rigidity signals lead to increased matrix-degrading activity at invadopodia, via a myosin II-FAK/Cas pathway. These data suggest a potential mechanism, via invadopodia, for the reported correlation of tissue density with cancer aggressiveness.
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http://dx.doi.org/10.1016/j.cub.2008.07.090DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2555969PMC
September 2008

Dependence of invadopodia function on collagen fiber spacing and cross-linking: computational modeling and experimental evidence.

Biophys J 2008 Sep 30;95(5):2203-18. Epub 2008 May 30.

Center of Cancer Systems Biology, Caritas St. Elizabeth's Medical Center, Tufts University School of Medicine, Boston, Massachusetts 02135, USA.

Invadopodia are subcellular organelles thought to be critical for extracellular matrix (ECM) degradation and the movement of cells through tissues. Here we examine invadopodia generation, turnover, and function in relation to two structural aspects of the ECM substrates they degrade: cross-linking and fiber density. We set up a cellular automaton computational model that simulates ECM penetration and degradation by invadopodia. Experiments with denatured collagen (gelatin) were used to calibrate the model and demonstrate the inhibitory effect of ECM cross-linking on invadopodia degradation and penetration. Incorporation of dynamic invadopodia behavior into the model amplified the effect of cross-linking on ECM degradation, and was used to model feedback from the ECM. When the model was parameterized with spatial fibrillar dimensions that closely matched the organization, in real life, of native ECM collagen into triple-helical monomers, microfibrils, and macrofibrils, little or no inhibition of invadopodia penetration was observed in simulations of sparse collagen gels, no matter how high the degree of cross-linking. Experimental validation, using live-cell imaging of invadopodia in cells plated on cross-linked gelatin, was consistent with simulations in which ECM cross-linking led to higher rates of both invadopodia retraction and formation. Analyses of invadopodia function from cells plated on cross-linked gelatin and collagen gels under standard concentrations were consistent with simulation results in which sparse collagen gels provided a weak barrier to invadopodia. These results suggest that the organization of collagen, as it may occur in stroma or in vitro collagen gels, forms gaps large enough so as to have little impact on invadopodia penetration/degradation. By contrast, dense ECM, such as gelatin or possibly basement membranes, is an effective obstacle to invadopodia penetration and degradation, particularly when cross-linked. These results provide a novel framework for further studies on ECM structure and modifications that affect invadopodia and tissue invasion by cells.
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http://dx.doi.org/10.1529/biophysj.108.133199DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2517013PMC
September 2008

N-cadherin gene expression in prostate carcinoma is modulated by integrin-dependent nuclear translocation of Twist1.

Cancer Res 2006 Apr;66(7):3365-9

Cancer Biology Graduate Interdisciplinary Program, and Department of Surgery, University of Arizona Health Sciences Center, 1501 North Campbell Avenue, Tucson, AZ 85724, USA.

The gain of N-cadherin expression in carcinomas has been shown to be important in the regulation of cell migration, invasion, and survival. Here, we show that N-cadherin mRNA expression in PC-3 prostate carcinoma cells is dependent on beta(1) integrin-mediated cell adhesion to fibronectin and the basic helix-loop-helix transcription factor Twist1. Depletion of Twist1 mRNA by small interfering RNA resulted in decreased expression of both Twist1 and N-cadherin and the inhibition of cell migration. Whereas Twist1 gene expression was independent of beta(1) integrin-mediated adhesion, Twist1 protein failed to accumulate in the nuclei of cells cultured in anchorage-independent conditions. The increased nuclear accumulation of Twist1 following cell attachment was suppressed by treatment with an inhibitor of Rho kinase or a beta(1) integrin neutralizing antibody. The effect of Twist1 on induction of N-cadherin mRNA required an E-box cis-element located within the first intron (+2,627) of the N-cadherin gene. These data raise the possibility that integrin-mediated adhesion to interstitial matrix proteins during metastasis differentially regulates the nuclear/cytoplasmic translocation and DNA binding of Twist1, activating N-cadherin transcription.
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http://dx.doi.org/10.1158/0008-5472.CAN-05-3401DOI Listing
April 2006

A national survey of electroconvulsive therapy use in the Russian Federation.

J ECT 2005 Sep;21(3):151-7

Russian University of People's Friendship, Department of Postgraduate Education of Medical Workers, Sub-faculty of Psycho-Somatic Pathology, Moscow, Russia.

A survey of electroconvulsive therapy (ECT) throughout Russia was undertaken to understand the range of ECT usage and knowledge. A survey form was distributed by mail to 1648 Russian doctors and institutions expected to deal with ECT. A total of 114 replies were received. They indicated that ECT is available to 22.4% of the country's population. In available regions, ECT is given to 1.43% of hospital admissions and 0.54 per 10,000 persons per year. ECT is used in Russian psychiatry, neurology, and addictionology. Outdated ECT instruments are used in more than one third of sites, and EEG and seizure quality are virtually never monitored. Fewer than 20% of ECTs are modified with anesthesia. There is no system or expectation for ECT training or privileging, there is no national organization that aims to advance ECT practice, and ECT research is haphazard. Nevertheless, most respondents are enthusiastic and positive about ECT, and most institutions are eager to adopt modern ECT methods.
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http://dx.doi.org/10.1097/01.yct.0000172569.44675.53DOI Listing
September 2005

Rational electroconvulsive therapy electrode placement.

Psychiatry (Edgmont) 2005 Jul;2(7):37-43

Dr. Swartz is from the Southern Illinois University, Springfield, Illinois.

Expertise in medicating depression requires experience with all types of antidepressants, including several medications within each type. Likewise, electroconvulsive therapy (ECT) proficiency includes experience with each of the modern electrode placements, of which there are four. Besides traditional bilateral and right unilateral placements, ECT electrode placement includes bifrontal and left anterior right temporal (LART) placements. In comparing antidepressant drugs, clinical trials have proven few differences of statistical significance, and useful proven differences are still more unusual. Analogously, few differences have been proven between ECT electrode placements, and many reported differences can be accounted for by large differences in electrical stimulus dosage. Still, the absence of proven differences does not show that there are no useful variations. This paper reviews the meaningful differences that are generally appreciated from clinical experience and biomedical principles for ECT electrode placement as well as antidepressant drugs.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3000196PMC
July 2005
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