SLAP deficiency decreases dsDNA autoantibody production.

Src-like adaptor protein (SLAP) adapts c-Cbl, an E3 ubiquitin ligase, to activated components of the BCR signaling complex regulating BCR levels and signaling in developing B cells. Based on this function, we asked whether SLAP deficiency could decrease the threshold for tolerance and eliminate development of autoreactive B cells in two models of autoantibody production. First, we sensitized mice with a dsDNA mimetope that causes an anti-dsDNA response. Despite equivalent production of anti-peptide antibodies compared to BALB/c controls, SLAP(-/-) mice did not produce anti-dsDNA. Second, we used the 56R tolerance model. SLAP(-/-) 56R mice had decreased levels of dsDNA-reactive antibodies compared to 56R mice due to skewed light chain usage. Thus, SLAP is a critical regulator of B-cell development and function and its deficiency leads to decreased autoreactive B cells that are otherwise maintained by inefficient receptor editing or failed negative selection.

Mixing-induced aggregation and associated microstructures in the capillary flow.

With a device that uses microscopic imaging as the signal detection method for online laser light scattering of solutions driven to flow in a capillary tube, we have found that mixing of a solution with water and vice versa induce large numbers of aggregates in the free flow stream. The degrees of aggregation as measured from the total number of aggregates and the corresponding light-scattering intensities are dependent on the species of the solution. This species dependence of the mixing aggregation in the capillary flow has the potential for the development of new protocols or even spectroscopic methods for the detection of solute molecules and the assessment of solution qualities. Furthermore, even with pure-distilled and de-ionized water in the steady-state capillary flow, there are still countable numbers of aggregates detectable in the free flow stream, although of extremely low concentration of an estimated value of no more than 10(-15) M .

Murine trophoblast-derived and pregnancy-associated exosome-enriched extracellular vesicle microRNAs: Implications for placenta driven effects on maternal physiology.

The role of extracellular vesicles (EVs), specifically exosomes, in intercellular communication likely plays a key role in placental orchestration of pregnancy and maternal immune sensing of the fetus. While murine models are powerful tools to study pregnancy and maternal-fetal immune interactions, in contrast to human placental exosomes, the content of murine placental and pregnancy exosomes remains largely understudied. Using a recently developed in vitro culture technique, murine trophoblast stem cells derived from B6 mice were differentiated into syncytial-like cells. EVs from the conditioned media, as well as from pregnant and non-pregnant sera, were enriched for exosomes. The RNA composition of these murine trophoblast-derived and pregnancy-associated exosome-enriched-EVs (ExoE-EVs) was determined using RNA-sequencing analysis and expression levels confirmed by qRT-PCR. Differentially abundant miRNAs were detected in syncytial differentiated ExoE-EVs, particularly from the X chromosome cluster (mmu-miR-322-3p, mmu-miR-322-5p, mmu-miR-503-5p, mmu-miR-542-3p, and mmu-miR-450a-5p). These were confirmed to be increased in pregnant mouse sera ExoE-EVs by qRT-PCR analysis. Interestingly, fifteen miRNAs were only present within the pregnancy-derived ExoE-EVs compared to non-pregnant controls. Mmu-miR-292-3p and mmu-miR-183-5p were noted to be some of the most abundant miRNAs in syncytial ExoE-EVs and were also present at higher levels in pregnant versus non-pregnant sera ExoE-EVs. The bioinformatics tool, MultiMir, was employed to query publicly available databases of predicted miRNA-target interactions. This analysis reveals that the X-chromosome miRNAs are predicted to target ubiquitin-mediated proteolysis and intracellular signaling pathways. Knowing the cargo of placental and pregnancy-specific ExoE-EVs as well as the predicted biological targets informs studies using murine models to examine not only maternal-fetal immune interactions but also the physiologic consequences of placental-maternal communication.

The discovery of a reciprocal relationship between tyrosine-kinase signaling and cullin neddylation.

While neddylation is known to activate cullin (CUL)-RING ubiquitin ligases (CRLs), its role in regulating T cell signaling is poorly understood. Using the investigational NEDD8 activating enzyme (NAE) inhibitor, MLN4924, we found that neddylation negatively regulates T cell receptor (TCR) signaling, as its inhibition increases IL-2 production, T cell proliferation and Treg development in vitro. We also discovered that loss of CUL neddylation occurs upon TCR signaling, and CRLs negatively regulate IL-2 production. Additionally, we found that tyrosine kinase signaling leads to CUL deneddylation in multiple cell types. These studies indicate that CUL neddylation is a global regulatory mechanism for tyrosine kinase signaling.