Increased migration of IgA lymphocytes to VIP nerve fibers after DSS-induced colitis

Immunoglobulin-positive lymphocytes are present close to vasoactive intestinal polypeptide-positive (VIP(+)) nerve fibers in the lamina propria of the intestinal tract, and have an important role in mucosal defense. The number of immunoglobulin A-positive (IgA(+)) cells close to the epithelial basement membrane and nerve fibers is increased by the administration of lipopolysaccharides, which induce IgA secretion into the intestinal lumen. The relationship between immunoglobulin-positive lymphocytes and the VIP(+) nerve fibers during inflammation, such as in inflammatory bowel disease, however, is not well known. The morphological relationship between immunoglobulin-positive cells and the basement membrane or the VIP(+) nerve fibers in the colon was examined using double immunofluorescent labeling in an inflammatory bowel disease mouse model created by oral administration of dextran sodium sulfate (DSS). DSS administration induced goblet cell loss, crypt loss, intestinal epithelium deformation and infiltration of inflammatory cells in the mucosa. In the colon, the number and percentage of IgA(+) lymphocytes close to the basement membrane and the VIP(+) nerve fibers in the lamina propria increased after DSS administration, in parallel with the pathologic progress in the inflamed tissue. On the other hand, the percentage of immunoglobulin G-positive (IgG(+)) lymphocytes close to the basement membrane and the VIP(+) nerve fibers decreased, although the total number of IgG(+) lymphocytes in the lamina propria increased. We suggest that the immunoglobulin-producing lymphocytes and enteric nerve fibers in the colon normally have a close morphological relationship, and that this relationship is reinforced in a cell-specific manner during inflammation.     

Regulation of casein kinase 2 by phosphorylation/dephosphorylation.

The effects of various polycation-stimulated (PCS) phosphatases and of the active catalytic subunit of the ATPMg-dependent (AMDc) protein phosphatase on the activity of casein kinase 2 (CK-2) were investigated by using the synthetic peptide substrate Ser-Glu-Glu-Glu-Glu-Glu, whose phosphorylated derivative is entirely insensitive to these protein phosphatases. Previous dephosphorylation of native CK-2 enhances its specific activity 2-3-fold. Such an effect, accounted for by an increase in Vmax, is more readily promoted by the PCS phosphatases than by the AMDc phosphatase. The phosphate incorporated by autophosphorylation could not be removed by the protein phosphatases, suggesting the involvement of phosphorylation site(s) other than the one(s) affected by intramolecular autophosphorylation. The activation of CK-2 by the phosphatase pretreatment is neutralized during the kinase assay; the mechanism of this phenomenon, which is highly dependent on the kinase concentration, is discussed.     

The Immunogenetic Architecture of Autoimmune Disease

The development of most autoimmune diseases includes a strong heritable component. This genetic contribution to disease ranges from simple Mendelian inheritance of causative alleles to the complex interactions of multiple weak loci influencing risk. The genetic variants responsible for disease are being discovered through a range of strategies from linkage studies to genome-wide association studies. Despite the rapid advances in genetic analysis, substantial components of the heritable risk remain unexplained, either owing to the contribution of an as-yet unidentified, “hidden,” component of risk, or through the underappreciated effects of known risk loci. Surprisingly, despite the variation in genetic control, a great deal of conservation appears in the biological processes influenced by risk alleles, with several key immunological pathways being modified in autoimmune diseases covering a broad spectrum of clinical manifestations. The primary translational potential of this knowledge is in the rational design of new therapeutics to exploit the role of these key pathways in influencing disease. With significant further advances in understanding the genetic risk factors and their biological mechanisms, the possibility of genetically tailored (or “personalized”) therapy may be realized.Autoimmune diseases affect a significant proportion of the population, with >4% of the European population suffering from one or more of these disorders (Vyse and Todd 1996; Cooper et al. 2009; Eaton et al. 2010). Although all autoimmune diseases share similarities in the basic immunological mechanisms, in other aspects, such as clinical manifestation and age of onset, individual diseases vary widely. A few rare autoimmune diseases with Mendelian inheritance patterns within families occur including APS-1 (autoimmune polyendocrine syndrome type 1), IPEX (immunodysregulation, polyendocrinopathy, and enteropathy X-linked) syndrome, and ALPS (autoimmune lymphoproliferative syndrome). Most autoimmune diseases are, however, multifactorial in nature, with susceptibility controlled by multiple genetic and environmental factors.The genetic component of more common autoimmune diseases can be calculated in several different manners, including the sibling recurrence risk (λ_s) and the twin concordance rate. The sibling recurrence risk is the ratio of the lifetime risk in siblings of patients to the lifetime population risk, whereas the twin concordance rate measures the proportion of the siblings of affected twins that are also affected. Most common autoimmune diseases, such as multiple sclerosis (MS), type 1 diabetes (T1D), rheumatoid arthritis (RA), and inflammatory bowel disease (IBD) are characterized by a sibling recurrence risk between 6 and 20 (Vyse and Todd 1996), and concordance rates of 25%–50% in monozygotic twins and 2%–12% in dizygotic twins (Cooper et al. 1999). A substantial proportion of relatives may also have subclinical evidence of autoimmunity without developing clinically overt disease. For example, 19% of healthy siblings of MS patients show antibody production in the cerebrospinal fluid, compared to 4% of unrelated healthy controls (Haghighi et al. 2000), whereas 4% of healthy first-degree relatives display lesions that are indistinguishable from those seen in patients and are not seen in unrelated healthy controls (De Stefano et al. 2006). Furthermore, comorbidity with the development of several autoimmune diseases in the same patient and clustering of several autoimmune diseases within families above what is expected by chance appear common (Cooper et al. 2009; Zhernakova et al. 2009). Together these data show a strong genetic component to autoimmune disease development.     

On the determination of the angular orientation of a vertebra

In this paper we consider the spatial orientation of vertebrae. We take the view that, in determining their rotation angles from X-rays, the procedure applied by Drerup yields the most reliable empirical results, viz. the three angles through which a vertebra rotates about its own symmetry axes in a specific sequence. With a view to the further use of this information to analyze deformations or the motion of a spine we recommend that the Drerup angles be converted into the well-known Eulerian angles. How this can be done is the subject of this report.     

Effect of Mg2, ATP and some analogs on phosphorylase phosphatase from adrenal cortex.

The effect of Mg2, ATP and some of its analogs was studied on the spontaneously active and the ATP-Mg-dependent forms of phosphorylase phosphatase extracted from adrenal cortex. Inhibition of the spontaneously active form was observed with Mg2 (Ki - 9mM), ATP (Ki = 9micronM), 2'-doxy-ATP (Ki = 8 micronM), AtetraP (Ki = 9 micronM), AMP(CH2)PP (Ki = 11 micronM), ADP(CH2)P (Ki = 19 micronM), ADP(NH)P (Ki = 16micronM) and ADP (Ki = 25micronM). Activation of the ATP-Mg-dependent form was obtained with Mg2 (Ka = 0.55mM) (to a lower extent) and with ATP (Ka = 2micronM), 2'-deoxy-ATP (Ka = 6micronM) or AtetraP (Ka = 15micronM) in the presence of 0.5mM Mg2. Activation with AMP(CH2)PP was only observed in the presence of high concentrations (5mM) of Mg2 (Ka = 13micronM). No activation at all was observed with ADP(CH2)P or ADP(NH)P. Even though the activation of the ATP-Mg-dependent form does not seem to involve a kinase reaction, the stimulation by ATP or its analogs is rather specific, since it does not occur with analogs in which a methylene group or a nitrogen is substituted for the oxygen between the beta- and gamma-phosphates.     

The catalytic subunit of protein phosphatase 2A associates with the translation termination factor eRF1.

By a number of criteria, we have demonstrated that the translation termination factor eRF1 (eukaryotic release factor 1) associates with protein phosphatase 2A (PP2A). Trimeric PP2A1 was purified from rabbit skeletal muscle using an affinity purification step. In addition to the 36 kDa catalytic subunit (PP2Ac) and established regulatory subunits of 65 kDa (PR65) and 55 kDa (PR55), purified preparations contained two proteins with apparent Mrs of 54 and 55 kDa. Protein microsequencing revealed that the 55 kDa component is a novel protein, whereas the 54 kDa protein was identified as eRF1, a protein that functions in translational termination as a polypeptide chain release factor. Using the yeast two-hybrid system, human eRF1 was shown to interact specifically with PP2Ac, but not with the PR65 or PR55 subunits. By deletion analysis, the binding domains were found to be located within the 50 N-terminal amino acids of PP2Ac, and between amino acid residues 338 and 381 in the C-terminal part of human eRF1. This association also occurs in vivo, since PP2A can be co-immunoprecipitated with eRF1 from mammalian cells. We observed a significant increase in the amount of PP2A associated with the polysomes when eRF1 was transiently expressed in COS1 cells, and eRF1 immunoprecipitated from those fractions contained associated PP2A. Since we did not observe any dramatic effects of PP2A on the polypeptide chain release activity of eRF1 (or vice versa), we postulate that eRF1 also functions to recruit PP2A into polysomes, thus bringing the phosphatase into contact with putative targets among the components of the translational apparatus.     

Modulating mouse innate immunity to RNA viruses by expressing the Bos taurus Mx system

Mx proteins are interferon-induced members of the dynamin superfamily of large guanosine triphosphatases. These proteins have attracted much attention because some display antiviral activity against pathogenic RNA viruses, such as members of the orthomyxoviridae, bunyaviridae, and rhabdoviridae families. Among the diverse mammalian Mx proteins examined so far, we have recently demonstrated in vitro that the Bos taurus isoform 1 (boMx1) is endowed with exceptional anti-rabies-virus activity. This finding has prompted us to seek an appropriate in vivo model for confirming and evaluating gene therapy strategies. Using a BAC transgene, we have generated transgenic mouse lines expressing the antiviral boMx1 protein and boMx2 proteins under the control of their natural promoter and short- and long-range regulatory elements. Expressed boMx1 and boMx2 are correctly assembled, as deduced from mRNA sequencing and western blotting. Poly-I/C-subordinated expression of boMx1 was detected in various organs by immunohistochemistry, and transgenic lines were readily classified as high- or low-expression lines on the basis of tissue boMx1 concentrations measured by ELISA. Poly-I/C-induced Madin-Darby bovine kidney cells, bovine turbinate cells, and cultured cells from high-expression line of transgenic mice were found to contain about the same concentration of boMx1, suggesting that this protein is produced at near-physiological levels. Furthermore, insertion of the bovine Mx system rendered transgenic mice resistant to vesicular-stomatitis-virus-associated morbidity and mortality, and embryonic fibroblasts derived from high-expression transgenic mice were far less permissive to the virus. These results demonstrate that the Bos taurus Mx system is a powerful anti-VSV agent in vivo and suggest that the transgenic mouse lines generated here constitute a good model for studying in vivo the various antiviral functions—known and yet to be discovered—exerted by bovine Mx proteins, with priority emphasis on the antirabic function of boMx1. M.-M. Garigliany and K. Cloquette have contributed equally to the study.