PRG2 and AQPEP are misexpressed in fetal membranes in placenta previa and percreta†.

The obstetrical conditions placenta accreta spectrum (PAS) and placenta previa are a significant source of pregnancy-associated morbidity and mortality, yet the specific molecular and cellular underpinnings of these conditions are not known. In this study, we identified misregulated gene expression patterns in tissues from placenta previa and percreta (the most extreme form of PAS) compared with control cases. By comparing this gene set with existing placental single-cell and bulk RNA-Seq datasets, we show that the upregulated genes predominantly mark extravillous trophoblasts. We performed immunofluorescence on several candidate molecules and found that PRG2 and AQPEP protein levels are upregulated in both the fetal membranes and the placental disk in both conditions. While this increased AQPEP expression remains restricted to trophoblasts, PRG2 is mislocalized and is found throughout the fetal membranes. Using a larger patient cohort with a diverse set of gestationally aged-matched controls, we validated PRG2 as a marker for both previa and PAS and AQPEP as a marker for only previa in the fetal membranes. Our findings suggest that the extraembryonic tissues surrounding the conceptus, including both the fetal membranes and the placental disk, harbor a signature of previa and PAS that is characteristic of EVTs and that may reflect increased trophoblast invasiveness.

Identification of SLED1 as a Potential Predictive Biomarker and Therapeutic Target of Post-Infarct Heart Failure by Bioinformatics Analyses.

The aim of this study was to explore potential predictive biomarkers and therapeutic targets of post-infarct heart failure (HF) using bioinformatics analyses.CEL raw data of GSE59867 and GSE62646 were downloaded from the GEO database. Differentially expressed genes (DEGs) between patients with ST-segment elevation myocardial infarction (STEMI) and those with stable coronary artery disease (CAD) at admission and DEGs between admission and 6 months after myocardial infarction (MI) in patients with STEMI were analyzed. A gene ontology (GO) analysis and a gene set enrichment analysis (GSEA) were performed, and a protein-protein interaction network was constructed. Critical genes were further analyzed.In total, 147 DEGs were screened between STEMI and CAD at admission, and 62 DEGs were identified in patients with STEMI between admission and 6 months after MI. The results of GO and GSEA indicate that neutrophils, neutrophil-related immunity responses, and monocytes/macrophages play important roles in MI pathogenesis. SLED1 expression was higher in patients with HF than in those without HF at admission and 1 month after MI. GSEA indicates that mTORC1 activation, E2F targets, G2M checkpoint, and MYC targets v1 inhibition may play key roles in the development of post-infarct HF. Furthermore, SLED1 may be involved in the development of post-infarct HF by activating mTORC1 and inhibiting E2F targets, G2M checkpoint, and MYC targets v1.SLED1 may be a novel biomarker of post-infarct HF and may serve as a potential therapeutic target in this disease.

Identification of gene expression predictors of occupational benzene exposure.

BACKGROUND: Previously, using microarrays and mRNA-Sequencing (mRNA-Seq) we found that occupational exposure to a range of benzene levels perturbed gene expression in peripheral blood mononuclear cells. OBJECTIVES: In the current study, we sought to identify gene expression biomarkers predictive of benzene exposure below 1 part per million (ppm), the occupational standard in the U.S. METHODS: First, we used the nCounter platform to validate altered expression of 30 genes in 33 unexposed controls and 57 subjects exposed to benzene (<1 to ≥5 ppm). Second, we used SuperLearner (SL) to identify a minimal number of genes for which altered expression could predict <1 ppm benzene exposure, in 44 subjects with a mean air benzene level of 0.55±0.248 ppm (minimum 0.203ppm). RESULTS: nCounter and microarray expression levels were highly correlated (coefficients >0.7, p<0.05) for 26 microarray-selected genes. nCounter and mRNA-Seq levels were poorly correlated for 4 mRNA-Seq-selected genes. Using negative binomial regression with adjustment for covariates and multiple testing, we confirmed differential expression of 23 microarray-selected genes in the entire benzene-exposed group, and 27 genes in the <1 ppm-exposed subgroup, compared with the control group. Using SL, we identified 3 pairs of genes that could predict <1 ppm benzene exposure with cross-validated AUC estimates >0.9 (p<0.0001) and were not predictive of other exposures (nickel, arsenic, smoking, stress). The predictive gene pairs are PRG2/CLEC5A, NFKBI/CLEC5A, and ACSL1/CLEC5A. They play roles in innate immunity and inflammatory responses. CONCLUSIONS: Using nCounter and SL, we validated the altered expression of multiple mRNAs by benzene and identified gene pairs predictive of exposure to benzene at levels below the US occupational standard of 1ppm.

Re-Expression of Bone Marrow Proteoglycan-2 by 5-Azacytidine is associated with STAT3 Inactivation and Sensitivity Response to Imatinib in Resistant CML Cells

Background: Epigenetic silencing of tumor suppressor genes (TSG) is involved in development and progression of cancers. Re-expression of TSG is inversely proportionate with STAT3 signaling pathways. Demethylation of DNA by 5-Azacytidine (5-Aza) results in re-expression of silenced TSG. Forced expression of PRG2 by 5-Aza induced apoptosis in cancer cells. Imatinib is a tyrosine kinase inhibitor that potently inhibits BCR/ ABL tyrosine kinase resulting in hematological remission in CML patients. However, majority of CML patients treated with imatinib would develop resistance under prolonged therapy. Methods: CML cells resistant to imatinib were treated with 5-Aza and cytotoxicity of imatinib and apoptosis were determined by MTS and annexin-V, respectively. Gene expression analysis was detected by real time-PCR, STATs activity examined using Western blot and methylation status of PRG2 was determined by pyrosequencing analysis. Result: Expression of PRG2 was significantly higher in K562-R+5-Aza cells compared to K562 and K562-R (p=0.001). Methylation of PRG2 gene was significantly decreased in K562-R+5-Aza cells compared to other cells (p=0.021). STAT3 was inactivated in K562-R+5-Aza cells which showed higher sensitivity to imatinib. Conclusion: PRG2 gene is a TSG and its overexpression might induce sensitivity to imatinib. However, further studies are required to evaluate the negative regulations of PRG2 on STAT3 signaling.

Eosinophil Cationic Protein (ECP), a predictive marker of bullous pemphigoid severity and outcome.

Bullous Pemphigoid (BP) is an inflammatory rare autoimmune bullous dermatosis, which outcome cannot be predicted through clinical investigations. Eosinophils are the main immune infiltrated cells in BP. However, the release of Major Basic Protein (MBP), Eosinophil Derived Neurotoxin (EDN), and Eosinophil Cationic Protein (ECP) upon eosinophil activation has still not been evaluated with respect to BP development. MBP, EDN and ECP were measured by ELISA in serum (n = 61) and blister fluid (n = 20) of patients with BP at baseline, and in serum after 2 months of treatment (n = 41). Eosinophil activation in BP patients was illustrated at baseline by significantly higher MBP, EDN and ECP serum concentrations as compared with control subjects (n = 20), but without distinction according to disease severity or outcome. EDN and ECP values were even higher in the blister fluids (P < 0.01 and P < 0.05, respectively), whereas MBP values were lower (P < 0.001). ECP serum concentration decreased after 60 days of treatment in BP patients with ongoing remission but not in patients who later relapsed (P < 0.05). A reduction of at least 12.8 ng/mL in ECP concentrations provided a positive predictive value for remission of 81%, showing that ECP serum variation could be a useful biomarker stratifying BP patients at risk of relapse.

Epigenome-wide DNA methylation study of IgE concentration in relation to self-reported allergies.

AIM: Epigenetic mechanisms are critical for normal immune development and epigenetic alterations might therefore be possible contributors to immune diseases. To investigate if DNA methylation in whole blood is associated with total and allergen-specific IgE levels. METHODS: We performed an epigenome-wide association study to investigate the association between DNA methylation and IgE level, allergen-specific IgE and self-reported immune diseases and allergies in 728 individuals. RESULTS: We identified and replicated 15 CpG sites associated with IgE, mapping to biologically relevant genes, including ACOT7, ILR5A, KCNH2, PRG2 and EPX. A total of 331 loci were associated with allergen-specific IgE, but none of these CpG sites were associated with self-reported allergies and immune diseases. CONCLUSION: This study shows that IgE levels are associated with DNA methylation levels at numerous CpG sites, which might provide new leads for investigating the links between IgE and allergic inflammation.

Reduced expression of granule proteins during extended survival of eosinophils in splenocyte culture with GM-CSF.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a multifaceted hematopoietic cytokine and the culture of mouse bone marrow with GM-CSF produces a variety of myeloid cells including granulocytes, macrophages, and dendritic cells. In the present study, we cultured mouse splenocytes with GM-CSF and examined the changes in hematopoietic cell populations over a week. Most of the splenic hematopoietic cells disappeared significantly from culture within 6days with or without the presence of GM-CSF. Among the splenic granulocyte populations, only eosinophils fully survived throughout the culture with GM-CSF for more than a week. During 10days of culture with GM-CSF, splenic eosinophils maintained their morphology as well as most of their surface molecules at high levels, including CCR3 and Siglec F. Meanwhile, the expression of mRNAs encoding major basic protein-1 (MBP-1) and eosinophil peroxidase (EPO), two major eosinophil-derived granule proteins, was diminished significantly from the cultured eosinophils. EPO assays also revealed that eosinophils in culture for more than 5days retained 30% or less EPO activity compared to those in uncultured splenocytes. In contrast, culture of splenocytes with GM-CSF did not change the capacity of eosinophils to migrate in response to eotaxin-1. Our results indicate that mouse splenic eosinophils are effectively cultured for lengthy periods while their expression of eosinophil-derived granule proteins is specifically suppressed. The relevance of these findings to eosinophilic inflammatory response is discussed.

A Novel In-Frame Deletion in the Leucine Zipper Domain of C/EBPε Leads to Neutrophil-Specific Granule Deficiency.

Neutrophil-specific granule deficiency (SGD) is a rare autosomal recessive primary immunodeficiency characterized by neutrophil dysfunction, bilobed neutrophil nuclei and lack of neutrophil-specific granules. Defects in a myeloid-specific transcription factor, CCAAT/enhancer binding protein-ε (C/EBPε), have been identified in two cases in which homozygous frameshift mutations led to loss of the leucine zipper domain. In this study, we report a 55-y-old woman affected with SGD caused by a novel homozygous 2-aa deletion (ΔRS) in the leucine zipper domain of the C/EBPε gene. The patient showed characteristic neutrophil abnormalities and recurrent skin infections; however, there was no history of deep organ infections. Biochemical analysis revealed that, in contrast to the two frameshift mutations, the ΔRS mutant maintained normal cellular localization, DNA-binding activity, and dimerization, and all three mutants exhibited marked reduction in transcriptional activity. The ΔRS mutant was defective in its association with Gata1 and PU.1, as well as aberrant cooperative transcriptional activation of eosinophil major basic protein. Thus, the ΔRS likely impairs protein-protein interaction with other transcription factors, resulting in a loss of transcriptional activation. These results further support the importance of the leucine zipper domain of C/EBPε for its essential function, and indicate that multiple molecular mechanisms lead to SGD.

Genome-wide expression profiles identify potential targets for gene-environment interactions in asthma severity.

BACKGROUND: Gene-environment interaction studies using genome-wide association study data are often underpowered after adjustment for multiple comparisons. Differential gene expression in response to the exposure of interest can capture the most biologically relevant genes at the genome-wide level. OBJECTIVE: We used differential genome-wide expression profiles from the Epidemiology of Home Allergens and Asthma birth cohort in response to Der f 1 allergen (sensitized vs nonsensitized) to inform a gene-environment study of dust mite exposure and asthma severity. METHODS: Polymorphisms in differentially expressed genes were identified in genome-wide association study data from the Childhood Asthma Management Program, a clinical trial in childhood asthmatic patients. Home dust mite allergen levels (<10 or ≥10 µg/g dust) were assessed at baseline, and (≥1) severe asthma exacerbation (emergency department visit or hospitalization for asthma in the first trial year) served as the disease severity outcome. The Genetics of Asthma in Costa Rica Study and a Puerto Rico/Connecticut asthma cohort were used for replication. RESULTS: IL9, IL5, and proteoglycan 2 expression (PRG2) was upregulated in Der f 1-stimulated PBMCs from dust mite-sensitized patients (adjusted P < .04). IL9 polymorphisms (rs11741137, rs2069885, and rs1859430) showed evidence for interaction with dust mite in the Childhood Asthma Management Program (P = .02 to .03), with replication in the Genetics of Asthma in Costa Rica Study (P = .04). Subjects with the dominant genotype for these IL9 polymorphisms were more likely to report a severe asthma exacerbation if exposed to increased dust mite levels. CONCLUSIONS: Genome-wide differential gene expression in response to dust mite allergen identified IL9, a biologically plausible gene target that might interact with environmental dust mite to increase severe asthma exacerbations in children.

Eosinophils mediate protective immunity against secondary nematode infection.

Eosinophils are versatile cells that regulate innate and adaptive immunity, influence metabolism and tissue repair, and contribute to allergic lung disease. Within the context of immunity to parasitic worm infections, eosinophils are prominent yet highly varied in function. We have shown previously that when mice undergo primary infection with the parasitic nematode Trichinella spiralis, eosinophils play an important immune regulatory role that promotes larval growth and survival in skeletal muscle. In this study, we aimed to address the function of eosinophils in secondary infection with T. spiralis. By infecting eosinophil-ablated mice, we found that eosinophils are dispensable for immunity that clears adult worms or controls fecundity in secondary infection. In contrast, eosinophil ablation had a pronounced effect on secondary infection of skeletal muscle by migratory newborn larvae. Restoring eosinophils to previously infected, ablated mice caused them to limit muscle larvae burdens. Passive immunization of naive, ablated mice with sera or Ig from infected donors, together with transfer of eosinophils, served to limit the number of newborn larvae that migrated in tissue and colonized skeletal muscle. Results from these in vivo studies are consistent with earlier findings that eosinophils bind to larvae in the presence of Abs in vitro. Although our previous findings showed that eosinophils protect the parasite in primary infection, these new data show that eosinophils protect the host in secondary infection.

IL-33 activates eosinophils of visceral adipose tissue both directly and via innate lymphoid cells.

Eosinophils are multifunctional leukocytes involved in allergic reactions as well as adipose tissue regulation. IL-5 is required for eosinophil survival; however, the in vivo mechanisms of eosinophil regulation are not fully understood. A tg mouse model with il5 promoter-driven EGFP expression was established for detecting the IL-5-producing cells in vivo. Il5-egfp tg mice expressed high levels of EGFP in gonadal adipose tissue (GAT) cells. EGFP(+) cells in GAT were mainly group 2 innate lymphoid cells (ILCs). IL-33 preferentially expanded EGFP(+) cells and eosinophils in GAT in vivo. EGFP(+) ILCs were found to upregulate prg2 mRNA expression in GAT eosinophils. These results demonstrate that ILCs activate eosinophils in GAT. The blockage of IL-33Rα, on the other hand, did not impair EGFP(+) ILC numbers but did impair eosinophil numbers in vivo. GAT eosinophils expressed IL-33Rα and IL-33 expanded eosinophil numbers in CD90(+) cell-depleted mice. IL-33 was further observed to induce the expression of retnla and epx mRNA in eosinophils. These findings demonstrate that IL-33 directly activates eosinophils in GAT, and together with our other findings described above, our findings show that IL-33 has dual pathways via which it activates eosinophils in vivo: a direct activation pathway and a group 2 ILC-mediated pathway.

Analysis of gene expression identifies candidate markers and pathways in pre-eclampsia.

Pre-eclampsia is a serious multisystem disorder and causes significant increase in both maternal and foetal morbidity and perinatal mortality globally. Due to the limited understanding of the molecular mechanism of pre-eclampsia, the current study conducted bioinformatic analyses to screen key regulators involved in pre-eclampsia. The gene expression profiling dataset GSE44711 containing 8 early-onset pre-eclampsia placentas and 8 gestational-age-matched control placentas was downloaded from the Gene Expression Omnibus database. Differentially expressed genes (DEGs) were screened by limma software package, which were then subjected to Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analysis on the Database for Annotation, Visualization, and Integrated Discovery website. Finally, protein-protein interaction network was constructed using the Search Tool for the Retrieval of Interacting Genes database. In total, 192 DEGs including 106 upregulated and 86 downregulated genes were obtained. Proteoglycan 2 and podoplanin were the most significantly up- and downregulated genes, respectively. In addition, three potential pathways and their related DEGs: spermidine/spermine N1-acetyltransferase 1, amiloride-binding protein 1 and adenosylmethionine decarboxylase 1 were associated with arginine and proline metabolism. Vascular endothelial growth factor C; phosphatidylinositol-4, 5-bisphosphate 3-kinase, catalytic subunit beta; collagen, type I, alpha 1 (COL1A1); and fibronectin 1 (FN1) were associated with focal adhesion. COL6A1 as well as COL1A1 and FN1 were involved in extra-cellular matrix-receptor interaction. The current study identified several potential genes and three pathways which may be considered as candidate targets for diagnosis and therapy of pre-eclampsia.

Eosinophil granule proteins: form and function.

Experimental and clinical data strongly support a role for the eosinophil in the pathogenesis of asthma, allergic and parasitic diseases, and hypereosinophilic syndromes, in addition to more recently identified immunomodulatory roles in shaping innate host defense, adaptive immunity, tissue repair/remodeling, and maintenance of normal tissue homeostasis. A seminal finding was the dependence of allergic airway inflammation on eosinophil-induced recruitment of Th2-polarized effector T-cells to the lung, providing a missing link between these innate immune effectors (eosinophils) and adaptive T-cell responses. Eosinophils come equipped with preformed enzymatic and nonenzymatic cationic proteins, stored in and selectively secreted from their large secondary (specific) granules. These proteins contribute to the functions of the eosinophil in airway inflammation, tissue damage, and remodeling in the asthmatic diathesis. Studies using eosinophil-deficient mouse models, including eosinophil-derived granule protein double knock-out mice (major basic protein-1/eosinophil peroxidase dual gene deletion) show that eosinophils are required for all major hallmarks of asthma pathophysiology: airway epithelial damage and hyperreactivity, and airway remodeling including smooth muscle hyperplasia and subepithelial fibrosis. Here we review key molecular aspects of these eosinophil-derived granule proteins in terms of structure-function relationships to advance understanding of their roles in eosinophil cell biology, molecular biology, and immunobiology in health and disease.

Smurf1 plays a role in EGF inhibition of BMP2-induced osteogenic differentiation.

It has been demonstrated that epidermal growth factor (EGF) plays a role in supporting the proliferation of bone marrow stromal cells in bone but inhibits their osteogenic differentiation. However, the mechanism underlying EGF inhibition of osteoblast differentiation remains unclear. Smurf1 is an E3 ubiquitin ligase that targets Smad1/5 and Runx2, which are critical transcription factors for bone morphogenetic protein 2 (BMP2)-induced osteoblast differentiation. In this study, we investigated the effect of EGF on the expression of Smurf1, and the role of Smurf1 in EGF inhibition of osteogenic differentiation using C2C12 cells, a murine myoblast cell line. EGF increased Smurf1 expression, which was blocked by inhibiting the activity of either JNK or ERK. Chromatin immunoprecipitation and Smurf1 promoter assays demonstrated that c-Jun and Runx2 play roles in the EGF induction of Smurf1 transcription. EGF suppressed BMP2-induced expression of osteogenic marker genes, which were rescued by Smurf1 knockdown. EGF downregulated the protein levels of Runx2 and Smad1 in a proteasome-dependent manner. EGF decreased the transcriptional activity of Runx2 and Smurf1, which was partially rescued by Smurf1 silencing. Taken together, these results suggest that EGF increases Smurf1 expression via the activation of JNK and ERK and the subsequent binding of c-Jun and Runx2 to the Smurf1 promoter and that Smurf1 mediates the inhibitory effect of EGF on BMP2-induced osteoblast differentiation.

Molecular analysis of non-specific protection against murine malaria induced by BCG vaccination.

Although the effectiveness of BCG vaccination in preventing adult pulmonary tuberculosis (TB) has been highly variable, epidemiologic studies have suggested that BCG provides other general health benefits to vaccinees including reducing the impact of asthma, leprosy, and possibly malaria. To further evaluate whether BCG immunization protects against malarial parasitemia and to define molecular correlates of this non-specific immunity, mice were vaccinated with BCG and then challenged 2 months later with asexual blood stage Plasmodium yoelii 17XNL (PyNL) parasites. Following challenge with PyNL, significant decreases in parasitemia were observed in BCG vaccinated mice relative to naïve controls. To identify immune molecules that may be associated with the BCG-induced protection, gene expression was evaluated by RT-PCR in i) naïve controls, ii) BCG-vaccinated mice, iii) PyNL infected mice and iv) BCG vaccinated/PyNL infected mice at 0, 1, 5, and 9 days after the P. yoelii infection. The expression results showed that i) BCG immunization induces the expression of at least 18 genes including the anti-microbial molecules lactoferrin, eosinophil peroxidase, eosinophil major basic protein and the cathelicidin-related antimicrobial peptide (CRAMP); ii) an active PyNL infection suppresses the expression of important immune response molecules; and iii) the extent of PyNL-induced suppression of specific genes is reduced in BCG-vaccinated/PyNL infected mice. To validate the gene expression data, we demonstrated that pre-treatment of malaria parasites with lactoferrin or the cathelicidin LL-37 peptide decreases the level of PyNL parasitemias in mice. Overall, our study suggests that BCG vaccination induces the expression of non-specific immune molecules including antimicrobial peptides which may provide an overall benefit to vaccinees by limiting infections of unrelated pathogens such as Plasmodium parasites.

Relationship of eosinophils and plasma cells to biofilm in chronic rhinosinusitis.

BACKGROUND: This study investigates the relationship of eosinophils and plasma cells to biofilm in chronic rhinosinusitis (CRS). A prospective observational study was performed at the Keck Hospital, University of Southern California, Department of Otolaryngology, Los Angeles, CA. METHODS: A total of 29 patients, 20 undergoing endoscopic sinus surgery for CRS and 9 control patients undergoing septoplasty for nasal obstruction without history or evidence of CRS, were included in this study. Contiguous sinonasal mucosa sample sections were examined by hematoxylin and eosin (H&E), fluorescence in situ hybridization (FISH), and immunohistochemistry (IHC) for biofilm, microbes, eosinophil major basic protein (EMBP), and cluster designation 27 (CD27). EMBP and CD27 were used as eosinophil and plasma cell markers, respectively. RESULTS: Biofilm was visualized in 15 of 20 patients with CRS on H&E sections, confirmed by microbial presence using FISH. Biofilm was not identified in tissue samples of the nine control patients. On IHC analysis, CD27 and EMBP expression were significantly higher in patients with CRS compared with control (p < 0.05) and had greater expression in biofilm-positive patients compared with biofilm-negative patients. Nasal polyps correlated with higher expression of CD27 and EMBP, but in CRS patients without polyps CD27 and EMBP was also significantly greater in biofilm-positive specimens compared with biofilm-negative specimens. CONCLUSION: Biofilm presence in CRS appears to correlate to host inflammatory response involving plasma cell and eosinophil recruitment.

Expression of the secondary granule proteins major basic protein 1 (MBP-1) and eosinophil peroxidase (EPX) is required for eosinophilopoiesis in mice.

Eosinophil activities are often linked with allergic diseases such as asthma and the pathologies accompanying helminth infection. These activities have been hypothesized to be mediated, in part, by the release of cationic proteins stored in the secondary granules of these granulocytes. The majority of the proteins stored in these secondary granules (by mass) are major basic protein 1 (MBP-1) and eosinophil peroxidase (EPX). Unpredictably, a knockout approach targeting the genes encoding these proteins demonstrated that, unlike in mice containing a single deficiency of only MBP-1 or EPX, the absence of both granule proteins resulted in the near complete loss of peripheral blood eosinophils with no apparent impact on any other hematopoietic lineage. Moreover, the absence of MBP-1 and EPX promoted a concomitant loss of eosinophil lineage-committed progenitors in the marrow, identifying a specific blockade in eosinophilopoiesis as the causative event. Significantly, this blockade of eosinophilopoiesis is also observed in ex vivo cultures of marrow progenitors and is not rescued in vivo by adoptive bone marrow engraftment, suggesting a cell-autonomous defect in marrow progenitors. These observations implicate a role for granule protein gene expression as a regulator of eosinophilopoiesis and provide another strain of mice congenitally deficient of eosinophils.

Plasticity-related gene 3 promotes neurite shaft protrusion.

BACKGROUND: Recently, we and others proposed plasticity-related gene 3 (PRG3) as a novel molecule in neuritogenesis based on PRG3 overexpression experiments in neuronal and non-neuronal cell lines. However, direct information on PRG3 effects in neuronal development and, in particular, its putative spatio-temporal distribution and conditions of action, is sparse. RESULTS: We demonstrate here that PRG3 induces filopodia formation in HEK293 cells depending on its N-glycosylation status. The PRG3 protein was strongly expressed during mouse brain development in vivo from embryonic day 16 to postnatal day 5 (E16 - P5). From P5 on, expression declined. Furthermore, in early, not yet polarized hippocampal cultured neurons, PRG3 was expressed along the neurite shaft. Knock-down of PRG3 in these neurons led to a decreased number of neurites. This phenotype is rescued by expression of an shRNA-resistant PRG3 construct in PRG3 knock-down neurons. After polarization, endogenous PRG3 expression shifted mainly to axons, specifically to the plasma membrane along the neurite shaft. These PRG3 pattern changes appeared temporally and spatially related to ongoing synaptogenesis. Therefore we tested (i) whether dendritic PRG3 re-enhancement influences synaptic currents and (ii) whether synaptic inputs contribute to the PRG3 shift. Our results rendered both scenarios unlikely: (i) PRG3 over-expression had no influence on miniature excitatory postsynaptic currents (mEPSC) and (ii) blocking of incoming signals did not alter PRG3 distribution dynamics. In addition, PRG3 levels did not interfere with intrinsic neuronal properties. CONCLUSION: Taken together, our data indicate that endogenous PRG3 promotes neurite shaft protrusion and therefore contributes to regulating filopodia formation in immature neurons. PRG3 expression in more mature neurons, however, is predominantly localized in the axon. Changes in PRG3 levels did not influence intrinsic or synaptic neuronal properties.

Gfi-1 inhibits the expression of eosinophil major basic protein (MBP) during G-CSF-induced neutrophilic differentiation.

The zinc finger transcriptional repressor Gfi-1 has been shown to play a critical role in early granulopoiesis; however, its role in late neutrophilic development is poorly understood. We report here that forced expression of a dominant negative Gfi-1 mutant, N382S, resulted in augmented mRNA levels of eosinophil major basic protein (MBP) in myeloid cells induced with G-CSF to undergo terminal neutrophilic differentiation. MBP is a cytotoxic protein that is abundantly expressed in eosinophils, but not in neutrophils. Ectopic expression of MBP inhibited the proliferation and survival of differentiating myeloid cells in response to G-CSF. Significantly, while GFI-1 is upregulated during neutrophilic differentiation, it is rapidly downregulated upon induction of eosinophilic differentiation, which was associated with increased MBP expression. Knockdown of GFI-1 in eosinophilic cells also led to increased level of MBP mRNA. These results indicate that Gfi-1 functions to inhibit the expression of MBP and aberrant expression of MBP as a result of loss of Gfi-1 function may cause premature apoptosis of differentiating neutrophils. In contrast, the rapid downregulation of Gfi-1 during eosinophilic development may allow for abundant expression of MBP, a hallmark of eosinophilic differentiation.

Acute hypersensitive-like injury in specific-pathogen-free chickens after infection with very virulent infectious bursal disease virus.

Very virulent infectious bursal disease virus (vvIBDV) can cause systemic inflammatory syndromes and acute death in specific-pathogen-free chickens within 72 h. However, the subtle mechanism of these severe inflammatory responses has been unsatisfactorily resolved until now. This study determined the kinetics of mast cells, tryptase, eosinophilic major basic protein, and eotaxin expression in specific-pathogen-free chickens after vvIBDV infection. Results showed that mast cell population, tryptase activity, major basic protein, and eotaxin expression were increased markedly in the vvIBDV-infected animals compared with the controls, with a significant difference in the bursa. Acute inflammatory lesions and high mortality were observed in vvIBDV-infected chickens. These observations implicate activated mast cells and eosinophils as important participants in vvIBDV-induced acute inflammatory lesions through mediators released in a short timeframe.