Collagens are functional, high affinity ligands for the inhibitory immune receptor LAIR-1

Collagens are the most abundant proteins in the human body, important in maintenance of tissue structure and hemostasis. Here we report that collagens are high affinity ligands for the broadly expressed inhibitory leukocyte-associated immunoglobulin-like receptor-1 (LAIR-1). The interaction is dependent on the conserved Gly-Pro-Hyp collagen repeats. Antibody cross-linking of LAIR-1 is known to inhibit immune cell function in vitro. We now show that collagens are functional ligands for LAIR-1 and directly inhibit immune cell activation in vitro. Thus far, all documented ligands for immune inhibitory receptors are membrane molecules, implying a regulatory role in cell–cell interaction. Our data reveal a novel mechanism of peripheral immune regulation by inhibitory immune receptors binding to extracellular matrix collagens.

Download Full-text

The Src-family kinase Lyn in immunoreceptor signaling

Endocrinology ◽

10.1210/endocr/bqab152 ◽

2021 ◽

Author(s):

Ben F Brian IV ◽

Tanya S Freedman

Keyword(s):

Autoimmune Disease ◽

Cell Activation ◽

Cell Function ◽

Immune Cell ◽

Organ Damage ◽

Src Family Kinase ◽

Immune Cell Activation ◽

Pathogen Elimination ◽

Tissue Healing ◽

Cancer Cell Signaling

Abstract Effective regulation of immune-cell activation is critical for ensuring that the immune response, and inflammation generated for the purpose of pathogen elimination, is limited in space and time to limit tissue damage. Autoimmune disease can occur when immunoreceptor signaling is dysregulated, leading to unrestrained inflammation and organ damage. Conversely, tumors can coopt the tissue-healing and immunosuppressive functions of hematopoietic cells to promote metastasis and evade therapy. The Src-family kinase Lyn is an essential regulator of immunoreceptor signaling, initiating both pro-inflammatory and suppressive signaling pathways in myeloid immune cells (e.g. neutrophils, dendritic cells, monocytes, macrophages) and in B lymphocytes. Defects in Lyn signaling are implicated in autoimmune disease, but mechanisms by which Lyn, expressed along with a battery of other Src-family kinases, may uniquely direct both positive and negative signaling remain incompletely defined. This review describes our current understanding of the activating and inhibitory contributions of Lyn to immunoreceptor signaling and how these processes contribute to myeloid and B-cell function. We also highlight recent work suggesting that the two proteins generated by alternative splicing of lyn, LynA and LynB, differentially regulate immune and cancer-cell signaling. These principles may also extend to other Lyn-expressing cells, such as neuronal and endocrine cells. Unraveling the common and cell-specific aspects of Lyn function could lead to new approaches to therapeutically targeting dysregulated pathways in pathologies from autoimmune and neurogenerative disease to cancer.

Download Full-text

Erratum: Bisphosphonate-induced differential modulation of immune cell function in gingiva and bone marrow in vivo: Role in osteoclast-mediated NK cell activation

Oncotarget ◽

10.18632/oncotarget.6431 ◽

2015 ◽

Vol 6 (38) ◽

pp. 41398-41398 ◽

Cited By ~ 1

Author(s):

Han-Ching Tseng ◽

Keiichi Kanayama ◽

Kawaljit Kaur ◽

So-Hyun Park ◽

Sil Park ◽

...

Keyword(s):

Bone Marrow ◽

Cell Activation ◽

Cell Function ◽

Immune Cell ◽

Nk Cell ◽

Differential Modulation ◽

Immune Cell Function

Download Full-text

Abstract P139: The Relationship Between Tissue Sodium Storage, Immune Cell Activation And Salt-sensitive Hypertension

Hypertension ◽

10.1161/hyp.76.suppl_1.p139 ◽

2020 ◽

Vol 76 (Suppl_1) ◽

Author(s):

Melis Sahinoz ◽

Fernando Elijovich ◽

Cheryl L Laffer ◽

Ashley Pitzer ◽

Thomas G Stewart ◽

...

Keyword(s):

Cell Activation ◽

Immune Cell ◽

Small Sample Size ◽

Salt Sensitivity ◽

Small Sample ◽

Sensitivity Index ◽

Salt Loading ◽

Immune Cell Activation ◽

Salt Depletion

Introduction: Salt Sensitivity (SS) of blood pressure (BP) is an independent predictor of death due to cardiovascular disease, but its pathogenesis is poorly understood. Sodium (Na + ) is stored in the skin and muscle interstitium. This hyperosmolar Na + activates monocytes in vitro via oxidative stress with generation of isolevuglandin (isoLG) protein adducts that are immunogenic and activate the adaptive immune system. Methods: Five subjects with essential hypertension discontinued all anti-hypertensive therapy for two weeks before the study. SS was assessed by an inpatient protocol of salt loading (460 mmoL/24h) and salt depletion (10 mmoL/24h, plus furosemide 40 mg x 3). Muscle and skin Na + contents were measured at baseline (BA) by 23 Sodium magnetic resonance imaging ( 23 NaMRI). Urine and serum electrolytes, glomerular filtration rate and the % CD14 + monocytes containing isoLG adducts using flow cytometry were obtained at BA, after salt-loading (HI) and after salt-depletion (LO). All continuous data are displayed as median (interquartile range). Spearman’s correlation was used to test associations. Results: Median age was 54 years (44-55), 60% of subjects were female, screening systolic BP (SBP) was 140 mmHg (134-148), diastolic BP was 88 mmHg (84-99) and BMI was 35 kg/m 2 (30-39). SBP response to salt-depletion (salt-sensitivity index, SSI) varied from -13.8 to +1.8 mmHg. %isoLG + CD14 + cells were 48 (27-65) at BA, 55 (31-56) at HI, and 70 (33-72) at LO (p=0.594, by the Kruskal-Wallis test). The correlation between SSI and delta (Δ) %isoLG LO minus HI, was 0.86, [95% confidence interval (CI), -0.07-0.99] which may suggest conclusively as we gather more data that the greater the SSI, the larger the decrease in isoLGs by salt depletion. Muscle Na + content correlated with 24h urine Na + (BA) (r=0.90, 95% CI, 0.11-0.99), however, the correlation with BP, SSI or isoLGs was inconclusive, potentially due to the small sample size. Skin Na + content correlated with baseline %CD14IsoLG + (r=0.91; 95% CI, 0.12-0.99). Conclusions: Na + intake is a component of the determinants of muscle Na + . Skin Na + is associated with increased isoLGs in monocytes, a marker of immune cell activation. Variability in ΔCD14isoLG may serve as a biomarker for SS of BP in humans.

Download Full-text

Administration of cardiac mesenchymal cells modulates innate immunity in the acute phase of myocardial infarction in mice

Scientific Reports ◽

10.1038/s41598-020-71580-z ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Yi Kang ◽

Marjan Nasr ◽

Yiru Guo ◽

Shizuka Uchida ◽

Tyler Weirick ◽

...

Keyword(s):

Myocardial Infarction ◽

Innate Immunity ◽

Mechanism Of Action ◽

Cell Activation ◽

Cell Function ◽

Immune Cell ◽

Mesenchymal Cell ◽

Cell Types

Abstract Although cardiac mesenchymal cell (CMC) therapy mitigates post-infarct cardiac dysfunction, the underlying mechanisms remain unidentified. It is acknowledged that donor cells are neither appreciably retained nor meaningfully contribute to tissue regeneration—suggesting a paracrine-mediated mechanism of action. As the immune system is inextricably linked to wound healing/remodeling in the ischemically injured heart, the reparative actions of CMCs may be attributed to their immunoregulatory properties. The current study evaluated the consequences of CMC administration on post myocardial infarction (MI) immune responses in vivo and paracrine-mediated immune cell function in vitro. CMC administration preferentially elicited the recruitment of cell types associated with innate immunity (e.g., monocytes/macrophages and neutrophils). CMC paracrine signaling assays revealed enhancement in innate immune cell chemoattraction, survival, and phagocytosis, and diminished pro-inflammatory immune cell activation; data that identifies and catalogues fundamental immunomodulatory properties of CMCs, which have broad implications regarding the mechanism of action of CMCs in cardiac repair.

Download Full-text

AN IN VITRO IMMUNE CELL FUNCTION ASSAY IS SUPERIOR TO CLINICAL ESTIMATES OF OVERALL IMMUNOSUPPRESSION.

Transplantation Journal ◽

10.1097/00007890-200607152-01891 ◽

2006 ◽

Vol 82 (Suppl 2) ◽

pp. 697

Author(s):

&NA;

Keyword(s):

Cell Function ◽

Immune Cell ◽

Immune Cell Function

Download Full-text

IMMU-46. EXAMINATION OF THE EFFECTS OF DEXAMETHASONE ON THE EFFICACY OF IMMUNOTHERAPY IN GLIOMA USING GENE-MEDIATED CYTOTOXIC IMMUNOTHERAPY

Neuro-Oncology ◽

10.1093/neuonc/noz175.538 ◽

2019 ◽

Vol 21 (Supplement_6) ◽

pp. vi129-vi129

Author(s):

Marilin Koch ◽

Mykola Zdioruk ◽

M Oskar Nowicki ◽

Estuardo Aguilar ◽

Laura Aguilar ◽

...

Keyword(s):

T Cell ◽

T Cell Activation ◽

Cell Activation ◽

Cell Function ◽

Immune Cell ◽

Symptomatic Treatment ◽

Tumor Cell Death ◽

The Impact

Abstract RATIONALE Dexamethasone is frequently used in symptomatic treatment of glioma patients, although it is known to cause immune suppression. Checkpoint inhibitor immunotherapies have not yet been successful in glioma treatments. Gene-mediated cytotoxic immunotherapy (GMCI) is an immunotherapeutic approach that uses aglatimagene besadenovec with an anti-herpetic prodrug to induce immunogenic tumor cell death and immune cell attraction to the tumor site with potent CD8 T cell activation. GMCI is currently in clinical trials for solid tumors including glioblastoma, where it showed encouraging survival results in a Phase 2 study that did not limit the use of dexamethasone. However, the effects of dexamethasone on its efficacy have not been explored. METHODS We investigated the effects of dexamethasone on GMCI in vitro using cytotoxicity and T-cell-killing assays in glioblastoma cell lines. The impact of dexamethasone in vivo was assessed in an orthotopic syngeneic murine glioblastoma model. RESULTS Cyotoxicity assays showed that Dexamethasone has a slight impact on GMCI in vitro. In contrast, we observed a highly significant effect in T-cell-functional assays in which killing was greatly impaired. Immune cell response assays revealed a reduced T-cell proliferation after co-culture with supernatant from dexamethasone or combination treated glioblastoma cells in contrast to GMCI alone. In a murine model, the combination of GMCI and dexamethasone resulted in a significant reduction in median symptom-free survival (29d) in comparison to GMCI alone (39.5d) (P = 0.0184). CONCLUSION Our data suggest that high doses of dexamethasone may negatively impact the efficacy of immunotherapy for glioma, which may be a consequence of impaired T cell function. These results support the idea that there is a need in identifying possible alternatives to dexamethasone to maximize the effectiveness of immunostimulatory therapies such as GMCI.

Download Full-text

Neuraminidase inhibition contributes to influenza A virus neutralization by anti-hemagglutinin stem antibodies

Journal of Experimental Medicine ◽

10.1084/jem.20181624 ◽

2019 ◽

Vol 216 (2) ◽

pp. 304-316 ◽

Cited By ~ 21

Author(s):

Ivan Kosik ◽

Davide Angeletti ◽

James S. Gibbs ◽

Matthew Angel ◽

Kazuyo Takeda ◽

...

Keyword(s):

Neutralizing Antibodies ◽

Influenza A ◽

Cell Activation ◽

Immune Cell ◽

Broadly Neutralizing Antibodies ◽

Neutralization Activity ◽

Immune Cell Activation ◽

Influenza Virus Hemagglutinin ◽

Infected Cells

Broadly neutralizing antibodies (Abs) that bind the influenza virus hemagglutinin (HA) stem may enable universal influenza vaccination. Here, we show that anti-stem Abs sterically inhibit viral neuraminidase (NA) activity against large substrates, with activity inversely proportional to the length of the fibrous NA stalk that supports the enzymatic domain. By modulating NA stalk length in recombinant IAVs, we show that anti-stem Abs inhibit virus release from infected cells by blocking NA, accounting for their in vitro neutralization activity. NA inhibition contributes to anti-stem Ab protection in influenza-infected mice, likely due at least in part to NA-mediated inhibition of FcγR-dependent activation of innate immune cells by Ab bound to virions. Food and Drug Administration–approved NA inhibitors enhance anti-stem–based Fc-dependent immune cell activation, raising the possibility of therapeutic synergy between NA inhibitors and anti-stem mAb treatment in humans.

Download Full-text

GABAA receptor α4-subunit knockout enhances lung inflammation and airway reactivity in a murine asthma model

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.00107.2017 ◽

2017 ◽

Vol 313 (2) ◽

pp. L406-L415 ◽

Cited By ~ 14

Author(s):

Gene T. Yocum ◽

Damian L. Turner ◽

Jennifer Danielsson ◽

Matthew B. Barajas ◽

Yi Zhang ◽

...

Keyword(s):

T Cell ◽

T Cell Activation ◽

Immune Cells ◽

Cell Activation ◽

Cell Function ◽

Immune Cell ◽

Therapeutic Potential ◽

Ex Vivo ◽

Asthma Model

Emerging evidence indicates that hypnotic anesthetics affect immune function. Many anesthetics potentiate γ-aminobutyric acid A receptor (GABAAR) activation, and these receptors are expressed on multiple subtypes of immune cells, providing a potential mechanistic link. Like immune cells, airway smooth muscle (ASM) cells also express GABAARs, particularly isoforms containing α4-subunits, and activation of these receptors leads to ASM relaxation. We sought to determine if GABAAR signaling modulates the ASM contractile and inflammatory phenotype of a murine allergic asthma model utilizing GABAAR α4-subunit global knockout (KO; Gabra40/0) mice. Wild-type (WT) and Gabra4 KO mice were sensitized with house dust mite (HDM) antigen or exposed to PBS intranasally 5 days/wk for 3 wk. Ex vivo tracheal rings from HDM-sensitized WT and Gabra4 KO mice exhibited similar magnitudes of acetylcholine-induced contractile force and isoproterenol-induced relaxation ( P = not significant; n = 4). In contrast, in vivo airway resistance (flexiVent) was significantly increased in Gabra4 KO mice ( P < 0.05, n = 8). Moreover, the Gabra4 KO mice demonstrated increased eosinophilic lung infiltration ( P < 0.05; n = 4) and increased markers of lung T-cell activation/memory (CD62L low, CD44 high; P < 0.01, n = 4). In vitro, Gabra4 KO CD4+ cells produced increased cytokines and exhibited increased proliferation after stimulation of the T-cell receptor as compared with WT CD4+ cells. These data suggest that the GABAAR α4-subunit plays a role in immune cell function during allergic lung sensitization. Thus GABAAR α4-subunit-specific agonists have the therapeutic potential to treat asthma via two mechanisms: direct ASM relaxation and inhibition of airway inflammation.

Download Full-text