A regulatory role for IL-10 receptor signaling in development and B cell help of T follicular helper cells in mice

IL -10 is widely accepted as a survival, proliferation, and differentiation factor for B cells. However, IL-10 deficiency accelerates disease progression as the result of autoantibody production in many autoimmune disease models. It was demonstrated that T follicular helper cells (T(FH) cells) play a key role in helping B cells that are secreting Abs. In this study, we demonstrated a regulatory role for IL-10R signaling on the development and B cell help function of T(FH) cells in vitro and in vivo. IL-1R subunit β-deficient (Il10rb(-/-)) Th cells were able to differentiate more readily into T(FH) cells, as well as secrete more IL-21 and IL-17 compared with wild-type Th cell-derived T(FH) cells. Increased IL-21 and IL-17 contributed to the enhanced B cell help functions of T(FH) cells. Further experiments demonstrated that IL-6 and IL-23 from dendritic cells in Il10rb(-/-) mice contributed to the differentiation of naive Th cells into T(FH) cells, as well as the generation of IL-21- and IL-17-producing T(FH) cells. Our results provide useful information for clarifying the immunoregulatory mechanisms associated with IL-10 deficiency in certain autoimmune disease models. This information could also be of benefit for the development of vaccines.     

Intrapulmonary administration of leukotriene B(4) augments neutrophil accumulation and responses in the lung to Klebsiella infection in CXCL1 knockout mice

In prior studies, we demonstrated that 1) CXCL1/KC is essential for NF-κB and MAPK activation and expression of CXCL2/MIP-2 and CXCL5/LPS-induced CXC chemokine in Klebsiella-infected lungs, and 2) CXCL1 derived from hematopoietic and resident cells contributes to host immunity against Klebsiella. However, the role of CXCL1 in mediating neutrophil leukotriene B(4) (LTB(4)), reactive oxygen species (ROS), and reactive nitrogen species (RNS) production is unclear, as is the contribution of these factors to host immunity. In this study, we investigated 1) the role of CXCL1 in LTB(4), NADPH oxidase, and inducible NO synthase (iNOS) expression in lungs and neutrophils, and 2) whether LTB(4) postinfection reverses innate immune defects in CXCL1(-/-) mice via regulation of NADPH oxidase and iNOS. Our results demonstrate reduced neutrophil influx, attenuated LTB(4) levels, and decreased ROS and iNOS production in the lungs of CXCL1(-/-) mice after Klebsiella pneumoniae infection. Using neutrophil depletion and repletion, we found that neutrophils are the predominant source of pulmonary LTB(4) after infection. To treat immune defects in CXCL1(-/-) mice, we intrapulmonarily administered LTB(4). Postinfection, LTB(4) treatment reversed immune defects in CXCL1(-/-) mice and improved survival, neutrophil recruitment, cytokine/chemokine expression, NF-κB/MAPK activation, and ROS/RNS production. LTB(4) also enhanced myeloperoxidase, H(2)O(2,) RNS production, and bacterial killing in K. pneumoniae-infected CXCL1(-/-) neutrophils. These novel results uncover important roles for CXCL1 in generating ROS and RNS in neutrophils and in regulating host immunity against K. pneumoniae infection. Our findings suggest that LTB(4) could be used to correct defects in neutrophil recruitment and function in individuals lacking or expressing malfunctional CXCL1.     

Crystal structure of the urokinase receptor in a ligand-free form

The urokinase receptor urokinase-type plasminogen activator receptor (uPAR) is a surface receptor capable of not only focalizing urokinase-type plasminogen activator (uPA)-mediated fibrinolysis to the pericellular micro-environment but also promoting cell migration and chemotaxis. Consistent with this multifunctional role, uPAR binds several extracellular ligands, including uPA and vitronectin. Structural studies suggest that uPAR possesses structural flexibility. It is, however, not clear whether this flexibility is an inherent property of the uPAR structure per se or whether it is induced upon ligand binding. The crystal structure of human uPAR in its ligand-free state would clarify this issue, but such information remains unfortunately elusive. We now report the crystal structures of a stabilized, human uPAR (H47C/N259C) in its ligand-free form to 2.4 Å and in complex with amino-terminal fragment (ATF) to 3.2 Å. The structure of uPAR^H47C/N259C in complex with ATF resembles the wild-type uPAR·ATF complex, demonstrating that these mutations do not perturb the uPA binding properties of uPAR. The present structure of uPAR^H47C/N259C provides the first structural definition of uPAR in its ligand-free form, which represents one of the biologically active conformations of uPAR as defined by extensive biochemical studies. The domain boundary between uPAR DI–DII domains is more flexible than the DII–DIII domain boundary. Two important structural features are highlighted by the present uPAR structure. First, the DI–DIII domain boundary may face the cell membrane. Second, loop 130–140 of uPAR plays a dynamic role during ligand loading/unloading. Together, these studies provide new insights into uPAR structure–function relationships, emphasizing the importance of the inter-domain dynamics of this modular receptor.     

A novel porcine circovirus type 2a strain, 10JS-2, with eleven-nucleotide insertions in the origin of genome replication

Here, we report a novel porcine circovirus type 2a (PCV2a) strain with 11 nucleotides (nt) inserted in the origin of genome replication (Ori). This is the first report of a PCV2a strain with nucleotide insertion in Ori. Our study will help further epidemiological studies and extend our knowledge of evolutionary characteristics of PCV2.     

Nine Complete Genome Sequences of Cutaneous Human Papillomavirus Genotypes Isolated from Healthy Skin of Individuals Living in Rural He Nan Province,China

Nine novel human papillomavirus (HPV) types were isolated from healthy skin of individuals in rural Anyang, China. All of these isolates belong to the genus Gammapapillomavirus. These data will provide us with useful information for a better understanding of PV evolution and the relationship of PV with the host.     

Molecular characterization of oilseed rape accessions collected from multi continents for exploitation of potential heterotic group through SSR markers

Evaluation of the genetic diversity in conventional and modern rapeseed cultivars is essential for conservation, management and utilization of these genetic resources for high yielding hybrid production. The objective of this research was to evaluate a collection of 86 oilseed rape cultivars with 188 simple sequence repeat (SSR) markers to assess the genetic variability, heterotic group identity and relationships within and between the groups identified among the genotypes. A total of 631 alleles at 188 SSR markers were detected including 53 and 84 unique and private alleles respectively, which indicated great richness and uniqueness of genetic variation in these selected cultivars. The mean number of alleles per locus was 3.3 and the average polymorphic information content was 0.35 for all microsatellite loci. Unweighted Pair Group Method with Arithmetic Mean clustering and principal component analysis consistently divided all the cultivars into four distinct groups (I, II, III and IV) which largely coincided with their geographical distributions. The Chinese origin cultivars are predominantly assembled in Group II and showed wide genetic base because of its high allelic abundance at SSR loci while most of the exotic cultivars grouped into Group I and were highly distinct owing to the abundant private and unique alleles. The highest genetic distance was found between Group I and IV, which mainly comprised of exotic and newly synthesized yellow seeded (1728-1 and G1087) breeding lines, respectively. Our study provides important insights into further utilization of exotic Brassica napus accessions in Chinese rapeseed breeding and vice versa.     

Identification of a new gene encoding 5-enolpyruvylshikimate-3-phosphate synthase using genomic library construction strategy

Applying the genomic library construction strategy and colony screening, a new aroA gene encoding 5-enolpyruvylshikimate-3-phosphate synthase has been identified, cloned and overexpressed in Escherichia coli, and the enzyme was purified to homogeneity. Kinetic analysis of the AroA _{P.fluorescens} indicated that the full-length enzyme exhibits 10-fold increased IC50 and an approximately 38-fold increased K _i for glyphosate compared to those of the AroA _E.coli , while retaining high affinity for the substrate phosphoenolpyruvate. Furthermore, we have transformed the new aroA _{P.fluorescens} gene into Arabidopsis thaliana via a floral dip method, and demonstrated that transgenic A. thaliana plants exhibit significant glyphosate resistance when compared with the wild type.     

Mutations in the exon 10 of prolactin receptor gene change the egg production performance in Wanjiang white goose

To select the molecular genetic markers related to egg performance of Wanjiang white goose, prolactin receptor gene (PRLR) was adopted to be a candidate gene in our study. Five pairs of primers (P1–P5) were designed to detect the SNPs of PRLR gene by PCR-SSCP method. The results revealed that polymorphisms were discovered in the PCR products amplified with P4 primers in PRLR exon 10, three genotypes were found: AA, AB and AC. The sequence of AB genotype is the same as original sequence (DQ660982) in NCBI. There are five mutations in AA genotype: C → A at 840 bp, C → T at 862 bp, T → C at 875 bp, T → A at 963 bp, A → T at 989 bp, resulting in amino acid mutations: His → Asn, Thr → Ile, Asn → Lys, Thr → Ser, and synonymous mutation at 875 bp. Sequencing revealed five mutations in AC genotype: G → T at 816 bp, A → T at 861 bp, C → T at 862 bp, T → C at 875 bp, A → G at 948 bp, causing amino acid mutations of Val → Phe, Thr → Phe, synonymous mutations at 875 and 963 bp. Besides, there are an N-glycosylation site (NQSR), three casein kinase II phosphorylation sites including SIIE, SKTE, and SLMD in AA genotype; three casein kinase II phosphorylation sites including SIIE, SKTE, and TLMD in AB genotype; three casein kinase II phosphorylation sites including SIFE, SKTE, and TLMD in AC genotype. The annual egg yielding of AB genotype geese are significantly more than those of AA and AC genotype geese on the average (P < 0.05). It is suggested for the first time that PRLR is a promising candidate gene that can affect egg performance in Wanjiang white goose.