Leishmania major-derived lipophosphoglycan influences the host’s early immune response by inducing platelet activation and DKK1 production via TLR1/2

BackgroundPlatelets are rapidly deployed to infection sites and respond to pathogenic molecules via pattern recognition receptors (TLR, NLRP). Dickkopf1 (DKK1) is a quintessential Wnt antagonist produced by a variety of cell types including platelets, endothelial cells, and is known to modulate pro-inflammatory responses in infectious diseases and cancer. Moreover, DKK1 is critical for forming leukocyte-platelet aggregates and induction of type 2 cell-mediated immune responses. Our previous publication showed activated platelets release DKK1 following Leishmania major recognition.ResultsHere we probed the role of the key surface virulence glycoconjugate lipophosphoglycan (LPG), on DKK1 production using null mutants deficient in LPG synthesis (Δlpg1- and Δlpg2-). Leishmania-induced DKK1 production was reduced to control levels in the absence of LPG in both mutants and was restored upon re-expression of the cognate LPG1 or LPG2 genes. Furthermore, the formation of leukocyte-platelet aggregates was dependent on LPG. LPG mediated platelet activation and DKK1 production occurs through TLR1/2.ConclusionThus, LPG is a key virulence factor that induces DKK1 production from activated platelets, and the circulating DKK1 promotes Th2 cell polarization. This suggests that LPG-activated platelets can drive innate and adaptive immune responses to Leishmania infection

The Ursinus Weekly, November 20, 1950

14th Messiah will be given December 7th • Fifteen seniors honored with listing in annual publication of Who\u27s Who • WSSF drive kindles much campus activity • Thespians to give psychological mystery, Angel Street, December first and second • May Day petition deadline is Tuesday • Bloodmobile coming to Collegeville December 7 • Ruby group pictures to be taken after Thanksgiving • MSGA to seek vote on dorm amendment • Jones reads poems of Eliot to Tuesday night audience • Gillespie\u27s orchestra to furnish music for December 8 Sunnybrook senior ball • Editorial: Spirit of Thanksgiving; Dorm government: Its meaning; Counsel for the councils • Frosberg has three-fold job • Herbsleb discusses international law before local IRC • Freshmen women elect Jen Price chairman of decoration committee • Library work in progress • Undergrads invited to join competition in contract bridge • Dart tourney • Como concert postponed • Chess Club wins • Herbsleb addresses pre-legal society • Belles edged 2-1 by Owlette squad • Chestnut Hill falls to Snell\u27s Belles 5-0 • Jayvee coeds triumph over Chestnut Hill 2-0 • Diplomats win 2-0 over Bear booters • Dragons 5-1 victors over soccer squad • Plan student bowling • Grizzlies tie Susquehanna in grid season finale, 6-6https://digitalcommons.ursinus.edu/weekly/1553/thumbnail.jp

An Implantable Vascularized Protein Gel Construct That Supports Human Fetal Hepatoblast Survival and Infection by Hepatitis C Virus in Mice

Widely accessible small animal models suitable for the study of hepatitis C virus (HCV) in vivo are lacking, primarily because rodent hepatocytes cannot be productively infected and because human hepatocytes are not easily engrafted in immunodeficient mice.We report here on a novel approach for human hepatocyte engraftment that involves subcutaneous implantation of primary human fetal hepatoblasts (HFH) within a vascularized rat collagen type I/human fibronectin (rCI/hFN) gel containing Bcl-2-transduced human umbilical vein endothelial cells (Bcl-2-HUVEC) in severe combined immunodeficient X beige (SCID/bg) mice. Maturing hepatic epithelial cells in HFH/Bcl-2-HUVEC co-implants displayed endocytotic activity at the basolateral surface, canalicular microvilli and apical tight junctions between adjacent cells assessed by transmission electron microscopy. Some primary HFH, but not Huh-7.5 hepatoma cells, appeared to differentiate towards a cholangiocyte lineage within the gels, based on histological appearance and cytokeratin 7 (CK7) mRNA and protein expression. Levels of human albumin and hepatic nuclear factor 4alpha (HNF4alpha) mRNA expression in gel implants and plasma human albumin levels in mice engrafted with HFH and Bcl-2-HUVEC were somewhat enhanced by including murine liver-like basement membrane (mLBM) components and/or hepatocyte growth factor (HGF)-HUVEC within the gel matrix. Following ex vivo viral adsorption, both HFH/Bcl-2-HUVEC and Huh-7.5/Bcl-2-HUVEC co-implants sustained HCV Jc1 infection for at least 2 weeks in vivo, based on qRT-PCR and immunoelectron microscopic (IEM) analyses of gel tissue.The system described here thus provides the basis for a simple and robust small animal model of HFH engraftment that is applicable to the study of HCV infections in vivo

Spontaneous Intestinal Tumorigenesis in Apc/Min+ Mice Requires Altered T Cell Development with IL-17A

The control of inflammatory diseases requires functional regulatory T cells (Tregs) with significant Gata-3 expression. Here we address the inhibitory role of Tregs on intestinal tumorigenesis in the Apc/Min+ mouse model that resembles human familial adenomatous polyposis (FAP). Apc/Min+ mice had a markedly increased frequency of Foxp3+ Tregs and yet decreased Gata-3 expression in the lamina propria. To address the role of heterozygous Apc gene mutation in Tregs, we generated Foxp3-Cre, Apcflox/+ mice. Tregs from these mice effectively inhibited tumorigenesis comparable to wild type Tregs after adoptive transfer into Apc/Min+ mice, demonstrating that the heterozygous Apc gene mutation in Tregs does not induce the loss of control over tumor microenvironment. Adoptive transfer of in vitro generated Apc/Min+ iTregs (inducible Tregs) failed to inhibit intestinal tumorigenesis, suggesting that naïve CD4 T cells generated from Apc/Min+ mice thymus were impaired. We also showed that adoptively transferred IL-17A-deficient Apc/Min+ Tregs inhibited tumor growth, suggesting that IL-17A was critical to impair the tumor regression function of Apc/Min+ Tregs. Taken together, our results suggest that both T cell development in a functional thymus and IL-17A control the ability of Treg to inhibit intestinal tumorigenesis in Apc/Min+ mice

Therapeutic Potential of Gene-Modified Regulatory T Cells: From Bench to Bedside

Regulatory T cells (Tregs) are an important subset of adaptive immune cells and control immune reactions for maintaining homeostasis. Tregs are generated upon their encounter with self or non-self-antigen and mediate tolerance or suppress aberrant immune responses. A high level of specificity of Tregs to recognize antigen(s) suggested their instrumental potential to treat various inflammatory diseases. This review will first introduce seminal basic research findings in the field of Tregs over the last two decades pertinent to therapeutic approaches in progress. We will then discuss the previous approaches to use Tregs for therapeutic purposes and the more recent development of gene-modification approaches. The suppressive function of Tregs has been studied intensively in clinical settings, including cancer, autoimmunity, and allotransplantation. In cancer, Tregs are often aberrantly increased in their number, and their suppressor function inhibits mounting of effective antitumor immune responses. We will examine potential approaches of using gene-modified Tregs to treat cancer. In autoimmunity and allotransplantation, chronic inflammation due to inherent genetic defects in the immune system or mismatch between organ donor and recipient results in dysfunction of Tregs, leading to inflammatory diseases or rejection, respectively. Since the recognition of antigen is a central part in Treg function and their therapeutic use, the modulation of T cell receptor specificity will be discussed. Finally, we will focus on future novel strategies employing the therapeutic potential of Tregs using gene modification to broaden our perspective