Role of B cell and hematopoietic cell intrinsic actions of ERα in lupus pathogenesis

Lupus is a chronic autoimmune disease characterized by the presence of autoimmune B and T cells and the production of pathogenic antibodies against nuclear antigens. Lupus predominately affects women between menarche and menopause. There are both genetic and environmental risk factors which affect an individuals’ risk of developing lupus. Estrogens are a risk factor for developing lupus and are thought to contribute significantly to the initiation and progression of disease. In lupus-prone mice, genetic knockout of a receptor for estrogen, estrogen receptor alpha (ERα), causes significant attenuation of lupus. Previous studies have not identified the cell type or types which mediate the effects of ERα on lupus. Estrogen has many effects on the immune system which could contribute to the development of autoimmunity in susceptible individuals. Particularly, estrogen promotes the survival of highly autoreactive B cells. Therefore, we hypothesized that ERα expression in hematopoietic cells promotes lupus, and more specifically, that ERα in B cells promotes lupus. To test this hypothesis, we created two different murine models of lupus on the lupus-prone (NZB x NZW)F1 genetic background. To investigate the role of ERα in hematopoietic cells, we created chimeric mice with hematopoietic and non-hematopoietic cells with different ERα genotypes. Due to issues with the creation of successful chimeras, we were not able to use these mice to fully address our hypothesis. However, these studies revealed that estrogen plays a role in the success of hematopoietic reconstitution in females. To address the hypothesis that ERα expression in B cells promotes lupus, we created a (NZB x NZW)F1 model with B cell specific deletion of ERα. Although only a moderate proportion of B cells had successful deletion of ERα, this was sufficient to cause a significant attenuation of lupus. Mice with B cell specific ERα deletion had fewer activated B cells, produced fewer pathogenic autoantibodies, and had significantly prolonged survival compared to control mice. Therefore, these studies have shown that ERα expression in B cells promotes lupus in the (NZB x NZW)F1 model of lupus

Chaotic systems in complex phase space

This paper examines numerically the complex classical trajectories of the kicked rotor and the double pendulum. Both of these systems exhibit a transition to chaos, and this feature is studied in complex phase space. Additionally, it is shown that the short-time and long-time behaviors of these two PT-symmetric dynamical models in complex phase space exhibit strong qualitative similarities.Comment: 22 page, 16 figure

A dexamethasone prodrug reduces the renal macrophage response and provides enhanced resolution of established murine lupus nephritis

We evaluated the ability of a macromolecular prodrug of dexamethasone (P-Dex) to treat lupus nephritis in (NZB × NZW)F1 mice. We also explored the mechanism underlying the anti-inflammatory effects of this prodrug. P-Dex eliminated albuminuria in most (NZB × NZW)F1 mice. Furthermore, P-Dex reduced the incidence of severe nephritis and extended lifespan in these mice. P-Dex treatment also prevented the development of lupus-associated hypertension and vasculitis. Although P-Dex did not reduce serum levels of anti-dsDNA antibodies or glomerular immune complexes, P-Dex reduced macrophage recruitment to the kidney and attenuated tubulointerstitial injury. In contrast to what was observed with free dexamethasone, P-Dex did not induce any deterioration of bone quality. However, P-Dex did lead to reduced peripheral white blood cell counts and adrenal gland atrophy. These results suggest that P-Dex is more effective and less toxic than free dexamethasone for the treatment of lupus nephritis in (NZB × NZW)F1 mice. Furthermore, the data suggest that P-Dex may treat nephritis by attenuating the renal inflammatory response to immune complexes, leading to decreased immune cell infiltration and diminished renal inflammation and injury

Genetic effects on gene expression across human tissues

Characterization of the molecular function of the human genome and its variation across individuals is essential for identifying the cellular mechanisms that underlie human genetic traits and diseases. The Genotype-Tissue Expression (GTEx) project aims to characterize variation in gene expression levels across individuals and diverse tissues of the human body, many of which are not easily accessible. Here we describe genetic effects on gene expression levels across 44 human tissues. We find that local genetic variation affects gene expression levels for the majority of genes, and we further identify inter-chromosomal genetic effects for 93 genes and 112 loci. On the basis of the identified genetic effects, we characterize patterns of tissue specificity, compare local and distal effects, and evaluate the functional properties of the genetic effects. We also demonstrate that multi-tissue, multi-individual data can be used to identify genes and pathways affected by human disease-associated variation, enabling a mechanistic interpretation of gene regulation and the genetic basis of diseas

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Genetic effects on gene expression across human tissues

Characterization of the molecular function of the human genome and its variation across individuals is essential for identifying the cellular mechanisms that underlie human genetic traits and diseases. The Genotype-Tissue Expression (GTEx) project aims to characterize variation in gene expression levels across individuals and diverse tissues of the human body, many of which are not easily accessible. Here we describe genetic effects on gene expression levels across 44 human tissues. We find that local genetic variation affects gene expression levels for the majority of genes, and we further identify inter-chromosomal genetic effects for 93 genes and 112 loci. On the basis of the identified genetic effects, we characterize patterns of tissue specificity, compare local and distal effects, and evaluate the functional properties of the genetic effects. We also demonstrate that multi-tissue, multi-individual data can be used to identify genes and pathways affected by human disease-associated variation, enabling a mechanistic interpretation of gene regulation and the genetic basis of disease

A dexamethasone prodrug reduces the renal macrophage response and provides enhanced resolution of established murine lupus nephritis.

We evaluated the ability of a macromolecular prodrug of dexamethasone (P-Dex) to treat lupus nephritis in (NZB × NZW)F1 mice. We also explored the mechanism underlying the anti-inflammatory effects of this prodrug. P-Dex eliminated albuminuria in most (NZB × NZW)F1 mice. Furthermore, P-Dex reduced the incidence of severe nephritis and extended lifespan in these mice. P-Dex treatment also prevented the development of lupus-associated hypertension and vasculitis. Although P-Dex did not reduce serum levels of anti-dsDNA antibodies or glomerular immune complexes, P-Dex reduced macrophage recruitment to the kidney and attenuated tubulointerstitial injury. In contrast to what was observed with free dexamethasone, P-Dex did not induce any deterioration of bone quality. However, P-Dex did lead to reduced peripheral white blood cell counts and adrenal gland atrophy. These results suggest that P-Dex is more effective and less toxic than free dexamethasone for the treatment of lupus nephritis in (NZB × NZW)F1 mice. Furthermore, the data suggest that P-Dex may treat nephritis by attenuating the renal inflammatory response to immune complexes, leading to decreased immune cell infiltration and diminished renal inflammation and injury

Impact of treatment on hypertension, splenomegaly and vasculitis in (NZB × NZW)F1 mice.

<p>(A), Mean arterial pressure was measured at pretreatment, 4-week, 8-week, 12 week time points via tail-cuff method. For the saline group, measurements were obtained only for the subset of mice surviving at each time point: 12 mice at 4-week time point; 11 mice at 8-week time point; 9 mice at 12-week time point (B), Spleen mass was determined at the time of sacrifice in each mouse. (C), A representative hematoxylin and eosin stained histological section illustrating a splenic vessel from each treatment group is provided. The arrow indicates perivascular fibrin deposits indicative of vasculitis. Scale bars: 50 μm; the asterisk (*) indicates a statistically significant difference (<i>P</i> < 0.05) from the saline control group. The double asterisk (**) indicates a statistically significant difference (<i>P</i> < 0.05) from the Dex group. The dagger (†) indicates a statistically significant difference (<i>P</i> < 0.05) from the pretreatment time point of the same treatment group. For saline and Dex treatments, n=13; for P-Dex treatment, n=9.</p

Impact of treatment on tubulointerstitial inflammation and injury in (NZB × NZW)F1 mice.

<p>(A), Representative images of immunohistochemical staining of kidney sections from mice in the saline (n=13), Dex (n=13), and P-Dex (n=9) treatment groups are shown. Sections were stained with an anti-TLR9 antibody (brown) and counterstained with hematoxylin (blue). (B), Quantification of TLR9 staining is illustrated. (C), TLR9 transcript levels in the kidney were measured by quantitative RT-PCR. For the saline group, frozen kidneys were available for RNA extraction only from the 6 mice that survived until the 14-week time point. (D), Levels of LCN2 were measured in kidney lysates by ELISA. For the saline group, frozen kidneys were available for preparation of protein lysates only from the 6 mice that survived until the 14-week time point. Scale bars: 25 μm; the asterisk (*) indicates a statistically significant difference (<i>P</i> < 0.05) from the saline control group. </p