The TNF and TNF receptor superfamilies: integrating mammalian biology.

From the historically grown archive of protein−ligand complexes in the Protein Data Bank small organic ligands are extracted and interpreted in terms of their chemical characteristics and features. Subsequently, pharmacophores representing ligand−receptor interaction are derived from each of these small molecules and its surrounding amino acids. Based on a defined set of only six types of chemical features and volume constraints, three-dimensional pharmacophore models are constructed, which are sufficiently selective to identify the described binding mode and are thus a useful tool for in-silico screening of large compound databases. The algorithms for ligand extraction and interpretation as well as the pharmacophore creation technique from the automatically interpreted data are presented and applied to a rhinovirus capsid complex as application example.

LigandScout: 3-D pharmacophores derived from protein-bound ligands and their use as virtual screening filters.

B cells are important in the development of autoimmune disorders by mechanisms involving dysregulated polyclonal B-cell activation, production of pathogenic antibodies, and co-stimulation of autoreactive T cells. zTNF4 (BLyS, BAFF, TALL-1, THANK) is a member of the tumour necrosis factor (TNF) ligand family that is a potent co-activator of B cells in vitro and in vivo. Here we identify two receptors for zTNF4 and demonstrate a relationship between zTNF4 and autoimmune disease. Transgenic animals overexpressing zTNF4 in lymphoid cells develop symptoms characteristic of systemic lupus erythaematosus (SLE) and expand a rare population of splenic B-Ia lymphocytes. In addition, circulating zTNF4 is more abundant in NZBWF1 and MRL-lpr/lpr mice during the onset and progression of SLE. We have identified two TNF receptor family members, TACI and BCMA, that bind zTNF4. Treatment of NZBWF1 mice with soluble TACI-Ig fusion protein inhibits the development of proteinuria and prolongs survival of the animals. These findings demonstrate the involvement of zTNF4 and its receptors in the development of SLE and identify TACI-Ig as a promising treatment of autoimmune disease in humans.

TACI and BCMA are receptors for a TNF homologue implicated in B-cell autoimmune disease

Immunoglobulin (Ig) class-switch DNA recombination (CSR) is thought to be highly dependent upon engagement of CD40 on B cells by CD40 ligand on T cells. We show here that dendritic cells up-regulate BLyS and APRIL upon exposure to interferon-alpha, interferon-gamma or CD40 ligand. In the presence of interleukin 10 (IL-10) or transforming growth factor-beta, BLyS and APRIL induce CSR from C(mu) to C(gamma) and/or C(alpha) genes in B cells, whereas CSR to C(epsilon) requires IL-4. Secretion of class-switched antibodies requires additional stimulation by B cell antigen receptor engagement and IL-15. By eliciting CD40-independent Ig class switching and plasmacytoid differentiation, BLyS and APRIL critically link the innate and adaptive immune responses.

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DCs induce CD40-independent immunoglobulin class switching through BLyS and APRIL

▪ Abstract The significance of type I interferons (IFN-α/β) in biology and medicine renders research on their activities continuously relevant to our understanding of normal and abnormal (auto) immune responses. This relevance is bolstered by discoveries that unambiguously establish IFN-α/β, among the multitude of cytokines, as dominant in defining qualitative and quantitative characteristics of innate and adaptive immune processes. Recent advances elucidating the biology of these key cytokines include better definition of their complex signaling pathways, determination of their importance in modifying the effects of other cytokines, the role of Toll-like receptors in their induction, their major cellular producers, and their broad and diverse impact on both cellular and humoral immune responses. Consequently, the role of IFN-α/β in the pathogenesis of autoimmunity remains at the forefront of scientific inquiry and has begun to illuminate the mechanisms by which these molecules promote or inhibit systemic...

TYPE I INTERFERONS (α/β) IN IMMUNITY AND AUTOIMMUNITY

The cause of many autoimmune and inflammatory diseases is unresolved, although dysregulated production of tumor necrosis factor (TNF) family members appears to be important in many cases. BAFF, a new member of the TNF family, binds to B cells and costimulates their growth in vitro. Mice transgenic for BAFF have vastly increased numbers of mature B and effector T cells, and develop autoimmune-like manifestations such as the presence of high levels of rheumatoid factors, circulating immune complexes, anti–DNA autoantibodies, and immunoglobulin deposition in the kidneys. This phenotype is reminiscent of certain human autoimmune disorders and suggests that dysregulation of BAFF expression may be a critical element in the chain of events leading to autoimmunity.

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Mice transgenic for BAFF develop lymphocytic disorders along with autoimmune manifestations.

In excitable cells, small-conductance Ca2+-activated potassium channels (SK channels) are responsible for the slow after-hyperpolarization that often follows an action potential. Three SK channel subunits have been molecularly characterized. The SK3 gene was targeted by homologous recombination for the insertion of a gene switch that permitted experimental regulation of SK3 expression while retaining normal SK3 promoter function. An absence of SK3 did not present overt phenotypic consequences. However, SK3 overexpression induced abnormal respiratory responses to hypoxia and compromised parturition. Both conditions were corrected by silencing the gene. The results implicate SK3 channels as potential therapeutic targets for disorders such as sleep apnea or sudden infant death syndrome and for regulating uterine contractions during labor.

https://science.sciencemag.org/content/sci/289/5486/1942.full.pdf

Respiration and parturition affected by conditional overexpression of the Ca2+-activated K+ channel subunit, SK3.

Transgene insertions in the mouse often cause mutations at chromosomal loci. Analysis of insertion mutations that cause male sterility may lead to the identification of novel molecular mechanisms implicated in male fertility. Here we show a line of transgenic mice with dominant inheritance of male sterility (DMS) that was found amid several lines that were normally fertile. Transgene-positive males from this line invariably were sterile, whereas transgenic females and transgene-negative male littermates were fertile. Histologic analysis and TUNEL staining for apoptotic cells in DMS testis showed spermatogenesis arrest at metaphase of meiosis I (M-I), accompanied by massive apoptosis of spermatocytes. Meiosis I arrest was incomplete, however, as small numbers of spermatids and spermatozoa were found. Both round spermatids and spermatozoa were evaluated for their permissiveness in the assisted reproductive technologies intracytoplasmic sperm injection (ICSI) and round spermatid injection (ROSI). Surprisingly, ROSI but not ICSI gave live offspring, suggesting that mature sperm had deteriorated by the time of recovery from the epididymis. Mapping the transgene insertion by fluorescence in situ hybridization revealed a site on chromosome 14 D3-E1. Two candidate genes, GFRa2 and GnRH, that were previously mapped to that region and the functions of which in spermatogenesis are well established were not altered in DMS. As a consequence, positional cloning of the DMS locus will be essential to identify new molecules potentially involved in arrest at M-I. Furthermore, mice carrying this genetic trait might be useful for studies of assisted reproductive technologies and male contraceptives.

/pdf/transgene-insertion-induced-dominant-male-sterility-and-1qoip61qqy.pdf

Transgene Insertion Induced Dominant Male Sterility and Rescue of Male Fertility Using Round Spermatid Injection

Isolated mammalian stem cells sustainable in culture under glycolytic conditions and which maintain the potential to differentiate are provided. Further encompassed by the invention are functionally distinct subpopulations of stem cells with increased differentiation permissiveness.

Manfred Baetscher

Papers

Mice transgenic for BAFF develop lymphocytic disorders along with autoimmune manifestations.

Respiration and parturition affected by conditional overexpression of the Ca2+-activated K+ channel subunit, SK3.

Transgene Insertion Induced Dominant Male Sterility and Rescue of Male Fertility Using Round Spermatid Injection

Stem cell selection and differentiation

A new spin on hESC differentiation