Plasma concentration of thrombopoietin in dogs with immune thrombocytopenia.

Background: Immune thrombocytopenia (ITP) is a common cause of severe thrombocytopenia in dogs. The pathogenesis of nonassociative, primary ITP (pITP) appears complex, with ill-defined thrombopoietic response.

Objectives: Develop an immunoassay to measure plasma canine thrombopoietin (TPO) concentration and characterize TPO concentrations in dogs with pITP.

A library of chemically defined human N-glycans synthesized from microbial oligosaccharide precursors.

Synthesis of homogenous glycans in quantitative yields represents a major bottleneck to the production of molecular tools for glycoscience, such as glycan microarrays, affinity resins, and reference standards. Here, we describe a combined biological/enzymatic synthesis that is capable of efficiently converting microbially-derived precursor oligosaccharides into structurally uniform human-type N-glycans. Unlike starting material obtained by chemical synthesis or direct isolation from natural sources, which can be time consuming and costly to generate, our approach involves precursors derived from renewable sources including wild-type Saccharomyces cerevisiae glycoproteins and lipid-linked oligosaccharides from glycoengineered Escherichia coli.

Complex Negative Regulation of TLR9 by Multiple Proteolytic Cleavage Events.

TLR9 is an innate immune receptor important for recognizing DNA of host and foreign origin. A mechanism proposed to prevent excessive response to host DNA is the requirement for proteolytic cleavage of TLR9 in endosomes to generate a mature form of the receptor (TLR9(471-1032)). We previously described another cleavage event in the juxtamembrane region of the ectodomain that generated a dominant-negative form of TLR9.

Heat shock protein gp96 regulates Toll-like receptor 9 proteolytic processing and conformational stability.

Nucleic acid-sensing Toll-like receptors (TLRs) initiate innate immune responses to foreign RNA and DNA, yet can detect and respond to host DNA. To avoid autoimmune pathologies, nucleic acid sensing TLRs are tightly regulated. TLR9 primarily resides in the endoplasmic reticulum, traffics to endosomes, is proteolytically processed and responds to DNA.

Negative regulation of signaling by a soluble form of toll-like receptor 9.

Nucleic acid structures are highly conserved through evolution and when self nucleic acids are aberrantly detected by toll-like receptors (TLRs) they contribute to autoimmune disease. For this reason, multiple regulatory mechanisms exist to prevent immune responses to self nucleic acids. TLR9 is a nucleic acid-sensing TLR that is regulated at multiple levels including association with accessory proteins, intracellular localization and proteolytic processing.

TLR9 traffics through the Golgi complex to localize to endolysosomes and respond to CpG DNA.

Toll-like receptor 9 (TLR9) promiscuously binds self- and microbial DNA, but only microbial DNA elicits an inflammatory response. How TLR9 discriminates between self- and foreign DNA is unclear, but inappropriate localization of TLR9 permits response to self-DNA, suggesting that TLR9 localization and trafficking are critical components. The molecular mechanisms controlling the movement of TLR9 may provide new insight into the recognition of DNA in normal and in pathological conditions such as autoimmune systemic lupus erythematosus.

Cytoplasmic targeting motifs control localization of toll-like receptor 9.

Toll-like receptors (TLRs) are essential for host defense. Although several TLRs reside on the cell surface, nucleic acid recognition of TLRs occurs intracellularly. For example, the receptor for CpG containing bacterial and viral DNA, TLR9, is retained in the endoplasmic reticulum.