Expression of a Splicing Isoform of MAIR-V (CD300LF), an Inhibitory Immunoglobulin-Like Receptor on Myeloid Cells

Nrf2 activation mediates tumor-specific hepatic stellate cells-induced DIgR2 expression in dendritic cells

Our previous studies discovered that tumor-specific hepatic stellate cells (tHSCs) induced dendritic cell-derived immunoglobulin receptor 2 (DIgR2) expression in bone marrow-derived dendritic cells (mDCs), inhibiting splenic T cell activation. The current study aims to explore the underlying mechanism of DIgR2 expression by focusing on Nrf2 (nuclear-factor-E2-related factor 2) signaling. We show that tHSCs co-culture induced significant Nrf2 signaling activation in mDCs. The latter was evidenced by Nrf2-Keap1 disassociation, Nrf2 protein stabilization, accumulation and nuclear translocation. Expression of Nrf2-dependent genes, including heme oxygenase-1 (HO-1) and NAD(P)H:quinone oxidoreductase 1 (NQO1), were detected in tHSCs-co-cultured mDCs. Importantly tHSCs-induced DIgR2 expression was blocked by Nrf2 shRNA or knockout (KO, by CRISPR/Cas9 method). Conversely, forced activation of Nrf2, by Keap1 shRNA or the Nrf2 activators (3H-1,2-dithiole-3-thione and MIND4-17), induced significant DIgR2 expression. tHSCs stimulation induced reactive oxygen species (ROS) production in mDCs. Conversely, ROS scavengers inhibited tHSCs-induced ROS production, Nrf2 activation and DIgR2 expression in mDCs. Significantly, tHSCs inhibited production of multiple cytokines (CD80, CD86 and IL-12) in mDCs, reversed by Nrf2 depletion. Moreover, Nrf2 shRNA or KO attenuated splenic T cell inhibition by tHSCs-stimulated mDCs. Together, we conclude that Nrf2 activation mediates tHSCs-induced DIgR2 expression in mDCs.

DlgR2 knockdown boosts dendritic cell activity and inhibits hepatocellular carcinoma tumor in-situ growth

Tumor-specific hepatic stellate cells (tHSCs) positively participate in human hepatocellular carcinoma (HCC) tumorigenesis and progression. Our previous studies have shown that tHSCs co-culture with dendritic cells (DCs) induced DIgR2 (dendritic cell-derived immunoglobulin receptor 2) expression. The latter is a member of IgSF inhibitory receptor suppressing DCs-initiated antigen-specific T-cell responses. In the current study, we show that hepatic artery injection of DlgR2 siRNA significantly inhibited in-situ HCC xenograft growth in rat livers. Further, 5-FU-medied inhibition of in-situ HCC growth was dramatically sensitized with DlgR2 silence. DlgR2 siRNA injection indeed downregulated DlgR2 in ex-vivo cultured tumor-derived DCs (tDCs). More importantly, tDCs activity was boosted following DlgR2 siRNA. These cells presented with upregulated CD80, CD86 and MHC-II. Production of interleukin-12 and tumor necrosis factor-α was also increased in the DlgR2-silenced tDCs. We propose that DlgR2 knockdown likely boosts the activity of tumor-associated DCs, and inhibits growth of in-situ HCC xenografts.

Identification of new biomarkers for Acute Respiratory Distress Syndrome by expression-based genome-wide association study

Background

Accumulated to-date gene microarray data on Acute Respiratory Distress Syndrome (ARDS) in the Gene Expression Omnibus (GEO) represent a rich source for identifying new unsuspected targets and mechanisms of ARDS. The recently developed expression-based genome-wide association study (eGWAS) for analysis of GEO data was successfully used for analysis of gene expression of comparatively noncomplex adipose tissue, 75 % of which is represented by adipocytes. Although lung tissue is more heterogenic and does not possess a prevalent cell type for driving gene expression patterns, we hypothesized that eGWAS of ARDS samples will generate biologically meaningful results.

Methods

The eGWAS was conducted according to (Proc Natl Acad Sci U S A 109:7049-7054, 2012) and genes were ranked according to p values of chi-square test.

Results

The search of GEO retrieved 487 ARDS related entries. These entries were filtered for multiple qualitative and quantitative conditions and 219 samples were selected: mouse n_sham/ARDS = 67/92, rat n = 13/13, human cells n = 11/11, canine n = 6/6 with the following ARDS model distributions: mechanical ventilation (MV)/cyclic stretch n = 11; endotoxin (LPS) treatment n = 8; MV + LPS n = 3; distant organ injury induced ARDS n = 3; chemically induced ARDS n = 2; Staphylococcus aureus induced ARDS n = 2; and one experiment each for radiation and shock induced ARDS. The eGWAS of this dataset identified 42 significant (Bonferroni threshold P < 1.55 × 10⁻⁶) genes. 66.6 % of these genes, were associated previously with lung injury and include the well known ARDS genes such as IL1R2 (P = 4.42 × 10⁻¹⁹), IL1β (P = 3.38 × 10⁻¹⁷), PAI1 (P = 9.59 × 10⁻¹⁴), IL6 (P = 3.57 × 10⁻¹²), SOCS3 (P = 1.05 × 10⁻¹⁰), and THBS1 (P = 2.01 × 10⁻⁹). The remaining genes were new ARDS candidates. Expression of the most prominently upregulated genes, CLEC4E (P = 4.46 × 10⁻¹⁴) and CD300LF (P = 2.31 × 10⁻¹⁶), was confirmed by real time PCR. The former was also validated by in silico pathway analysis and the latter by Western blot analysis.

Conclusions

Our first in the field application of eGWAS in ARDS and utilization of more than 120 publicly available microarray samples of ARDS not only justified applicability of eGWAS to complex lung tissue, but also discovered 14 new candidate genes which associated with ARDS. Detailed studies of these new candidates might lead to identification of unsuspected evolutionarily conserved mechanisms triggered by ARDS.

Electronic supplementary material

The online version of this article (doi:10.1186/s12890-015-0088-x) contains supplementary material, which is available to authorized users.

Identification and Characterization of CD300H, a New Member of the Human CD300 Immunoreceptor Family

Recruitment of circulating monocytes and neutrophils to infection sites is essential for host defense against infections. Here, we identified a previously unannotated gene that encodes an immunoglobulin-like receptor, designated CD300H, which is located in the CD300 gene cluster. CD300H has a short cytoplasmic tail and associates with the signaling adaptor proteins, DAP12 and DAP10. CD300H is expressed on CD16(+) monocytes and myeloid dendritic cells. Ligation of CD300H on CD16(+) monocytes and myeloid dendritic cells with anti-CD300H monoclonal antibody induced the production of neutrophil chemoattractants. Interestingly, CD300H expression varied among healthy subjects, who could be classified into two groups according to "positive" and "negative" expression. Genomic sequence analysis revealed a single-nucleotide substitution (rs905709 (G → A)) at a splice donor site on intron 1 on either one or both alleles. The International HapMap Project database has demonstrated that homozygosity for the A allele of single nucleotide polymorphism (SNP) rs905709 ("negative" expression) is highly frequent in Han Chinese in Beijing, Japanese in Tokyo, and Europeans (A/A genotype frequencies 0.349, 0.167, and 0.138, respectively) but extremely rare in Sub-Saharan African populations. Together, these results suggest that CD300H may play an important role in innate immunity, at least in populations that carry the G/G or G/A genotype of CD300H.

CD300 molecule regulation of human dendritic cell functions

Dendritic cells (DC) are a heterogeneous population of leucocytes which play a key role in initiating and modulating immune responses. The human CD300 family consists of six immunoregulatory leucocyte membrane molecules that regulate cellular activity including differentiation, viability, cytokine and chemokine secretion, phagocytosis and chemotaxis. Recent work has identified polar lipids as probable ligands for these molecules in keeping with the known evolutionary conservation of this family. CD300 molecules are all expressed by DC; CD300b, d, e and f are restricted to different subpopulations of the myeloid DC lineage. They have been shown to regulate DC function both in vitro and in vivo. In addition DC are able to regulate their CD300 expression in an autocrine manner. The potential to form different CD300 heterodimers adds further complexity to their role in fine tuning DC function. Expression of CD300 molecules is altered in a number of diseases including many where DC are implicated in the pathogenesis. CD300 antibodies have been demonstrated to have significant therapeutic effect in animal models. The mechanisms underlying the immunoregulatory effects of the CD300 family are complex. Deciphering their physiology will allow effective targeting of these molecules as novel therapies in a wide variety of inflammatory diseases.

[Characteristics of peripheral rheograms following thermal provocation in normal and pathologic pregnancy]

Using the impedance plethysmographic method of rheography it is possible to ascertain the tone of the peripheral resistance vessels directly by simple means. Previous studies have shown that there is a close relationship between peripheral vasodilatation at rest and normal course of pregnancy. In the present study, rheographic changes were studied in patients with normal pregnancy (n = 27, Group 1), diabetes mellitus (n = 18, Group 2), "pregnancy-induced hypertension" (n = 10, Group 3), and chronic placental insufficiency (n = 16, Group 4) during and following a low-temperature stimulus. After exposure to icy water, the Group 1 subjects showed a 40% reduction in rheographic amplitude, Groups 2 and 3 a 25% reduction, while Group 4 patients showed no signs of vasoconstriction going beyond the resting state (p less than 0.001). The four groups also differed considerably as regards vessel wall behavior in the recovery phase. The study confirms that the amplitude of the peripheral rheogram is a good indicator for detecting high-risk pregnancies. The amplitude pattern under thermal stimulation also provides further information on the dynamic behavior of the resistance vessels in normal and pathologic pregnancies.