Leukocyte-associated Immunoglobulin-like Receptor-1 Research Articles

MARCO is a potential prognostic and immunotherapy biomarker

BackgroundMacrophage receptor with collagenous structure (MARCO), a novel immune checkpoint expressed on tumor-associated macrophages, has antitumor therapeutic properties. However, the association between MARCO and patient prognosis, immune infiltration, and ICI immunotherapy needs to be studied urgently. MethodsMARCO distribution in cancer tissues was investigated using the TCGA and GTEx databases. The PrognoScan and KM Plotter databases was used to assess the MARCO prognosis. TIMER2.0, GEPIA, cBioPortal, and GSEA all confirmed the link between MARCO and immune infiltration, mutation profile, and enrichment pathway analysis. Data visualization was implemented by R language. ResultsIn general, MARCO had a substantial impact on the prognosis of cancer patients and was expressed differently in cancer and adjacent normal tissues. High expression of MARCO was associated with poorer OS in bladder urothelial carcinoma (BLCA), breast invasive carcinoma (BRCA), lung squamous cell carcinoma (LUSC), colon adenocarcinoma (COAD), and prostate adenocarcinoma (PRAD). However, high expression of MARCO had a better PFI in brain lower-grade glioma (LGG) and skin cutaneous melanoma (SKCM). We discovered that MARCO expression was lowest in pancreatic adenocarcinoma (PAAD) and rectum adenocarcinoma (READ) stage 1, BLCA stage 2, LUSC and stomach adenocarcinoma (STAD) stage 3, and liver hepatocellular carcinoma (LIHC) stage 4. Subsequently, we analyzed the correlation between MARCO and 47 immune checkpoints and observed that MARCO was positively connected with CD80, CD86, and leukocyte-associated immunoglobulin-like receptor 1(LAIR1) in most cancers. In COAD, MARCO has the most microsatellite instability (MSI). In addition, we discovered that high expression of MARCO patients had a better prognosis after immune checkpoint inhibitor (ICI) treatment in SKCM. Finally, GSEA revealed a significant correlation between MARCO and TNF/NFκB signaling, KRAS signaling, PI3K/AKT/mTOR pathway, IL-6-STAT3 signaling, TGFβ pathway, and p53 pathway. ConclusionThis study comprehensively investigated the relationship between MARCO and clinical prognosis, immune infiltration, and ICI immunotherapy in various cancers. We demonstrated the potential of MARCO as an emerging biomarker, exploring new avenues for future tumor immunotherapy.

Proteomic and single-cell landscape reveals novel pathogenic mechanisms of HBV-infected intrahepatic cholangiocarcinoma

Despite the epidemiological association between intrahepatic cholangiocarcinoma (ICC) and hepatitis B virus (HBV) infection, little is known about the relevant oncogenic effects. A cohort of 32 HBV-infected ICC and 89 non-HBV-ICC patients were characterized using whole-exome sequencing, proteomic analysis, and single-cell RNA sequencing. Proteomic analysis revealed decreased cell-cell junction levels in HBV-ICC patients. The cell-cell junction level had an inverse relationship with the epithelial-mesenchymal transition (EMT) program in ICC patients. Analysis of the immune landscape found that more CD8 Tcells and Th2 cells were present in HBV-ICC patients. Single-cell analysis indicated that transforming growth factor beta signaling-related EMT program changes increased in tumor cells of HBV-ICC patients. Moreover, ICAM1+ tumor-associated macrophages are correlated with a poor prognosis and contributed to the EMT in HBV-ICC patients. Our findings provide new insights into the behavior of HBV-infected ICC driven by various pathogenic mechanisms involving decreased cell junction levels and increased progression of the EMT program.

Proteomic profiling of cerebrospinal fluid in pediatric myelin oligodendrocyte glycoprotein antibody-associated disease

BackgroundMyelin oligodendrocyte glycoprotein (MOG) antibody-associated disease (MOGAD) is an autoimmune demyelinating disorder of the central nervous system.MethodsExtracted proteins from 34 cerebrospinal fluid (CSF) samples [patients with MOGAD (MOG group, n = 12); healthy controls (HC group, n = 12); patients with MOG seronegative and metagenomics next-generation sequencing-negative inflammatory neurological diseases (IND group, n = 10)] were processed and subjected to label-free quantitative proteomics. Supervised partial least squares-discriminant analysis (PLS-DA) and orthogonal PLS-DA (O-PLS-DA) models were also performed based on proteomics data. Functional analysis of differentially expressed proteins (DEPs) was performed using Gene Ontology, InterPro, and Kyoto Encyclopedia Genes and Genomes. An enzyme-linked immunosorbent assay was used to determine the complement levels in serum from patients with MOGAD.ResultsFour hundred and twenty-nine DEPs (149 upregulated and 280 downregulated proteins) were identified in the MOG group compared to the HC group according to the P value and fold change (FC). Using the O-PLS-DA model, 872 differentially abundant proteins were identified with variable importance projection (VIP) scores > 1. Five proteins (gamma-glutamyl hydrolase, cathepsin F, interalpha-trypsin inhibitor heavy chain 5, latent transforming growth factor beta-binding protein 4 and leukocyte-associated immunoglobulin-like receptor 1) overlapping between the top 30 DEPs with top-ranked P value and FC and top 30 proteins in PLS-DA VIP lists were acquired. Functional analysis revealed that the dysregulated proteins in the MOG group were primarily involved in complement and coagulation cascades, cell adhesion, axon guidance, and glycosphingolipid biosynthesis compared to the HC group.ConclusionThe proteomic alterations in CSF samples from children with MOGAD identified in the current study might provide opportunities for developing novel biomarker candidates.

Differential isoform expression of Allergin-1 during acute and chronic inflammation.

Neutrophils are crucial to antimicrobial defense, but excessive neutrophilic inflammation elicits immune pathology. Currently, no effective treatment exists to curb neutrophil activation. However, neutrophils express a variety of inhibitory receptors which may represent potential therapeutic targets to limit neutrophilic inflammation. Indeed, we previously showed that the inhibitory collagen receptor leukocyte-associated immunoglobulin-like receptor 1 (LAIR-1) regulates neutrophilic airway inflammation and inhibits neutrophil extracellular trap formation. The inhibitory receptor Allergin-1 is expressed by myeloid cells and B cells. Allergin-1 suppresses mast cell and basophil activation, but a potential regulatory role on neutrophils remains unexplored. We aimed to demonstrate the regulation of neutrophils by Allergin-1. We examine Allergin-1 isoform expression on human neutrophils during homeostatic (healthy donors) and chronic inflammatory (systemic lupus erythematosus patients) conditions in comparison to other circulating leukocytes by flow cytometry. To reveal a potential role for Allergin-1 in regulating neutrophilic inflammation, we experimentally infect wild-type (WT) and Allergin-1-deficient mice with a respiratory syncytial virus (RSV) and monitor disease severity and examine cellular airway infiltrate. Flow cytometry was used to confirm Allergin-1 expression by airway-infiltrated neutrophils in RSV infection-induced bronchiolitis patients. Only the short 1 (S1) isoform, but not the long (L) or S2 isoform could be detected on blood leukocytes, with the exception of nonclassical monocytes, which exclusively express the S2 isoform. Allergin-1 expression levels did not vary significantly between healthy individuals and patients with the systemic inflammatory disease on any interrogated cell type. Airway-infiltrated neutrophils of pediatric RSV bronchiolitis patients were found to express Allergin-1S1. However, Allergin-1-deficient mice experimentally infected with RSV did not show exacerbated disease or increased neutrophil airway infiltration compared to WT littermates. Allergin-1 isoform expression is unaffected by chronic inflammatory conditions. In stark contrast to fellow inhibitory receptor LAIR-1, Allergin-1 does not regulate neutrophilic inflammation in a mouse model of RSV bronchiolitis.

A Phase 1, Open-Label, Safety, Tolerability, and Efficacy Study of NC525 in Subjects with Advanced Myeloid Neoplasms

Background With the exception of certain select subtypes, Acute Myeloid Leukemia (AML) remains incurable for a majority of patients with current therapies. Despite recent drug approvals targeting actionable molecular mutations and BCL-2, relapse remains inevitable for most patients with AML due to leukemia-initiating cells and progenitors {i.e., leukemic stem cells (LSCs)} which are resistant to conventional cytotoxic drugs. Novel agents that preferentially target LSCs to lessen or eliminate the risk for relapse while avoiding significant myelosuppression by sparing normal hematopoietic stem cells (HSCs), are highly sought-after anti-leukemia therapeutics. Leukocyte Associated Immunoglobulin-like Receptor 1 (LAIR-1) is an immune inhibitory receptor that is present on most immune cell subsets, including T cells, NK cells, monocytes, macrophages, dendritic cells, and granulocytes. LAIR-1, a surface leukocyte receptor containing two immune receptor tyrosine-based inhibitory motifs (ITIM), binds to endogenous collagen ligands and plays an important role in inducing an immunosuppressive microenvironment. In AML, the engagement of LAIR-1 inhibits intracellular downstream survival signals, leading to decreased GM-CSF-mediated survival and proliferation of AML blasts. LAIR-1 is expressed on AML blasts and LSCs regardless of FAB subtypes, cytogenetics or molecular mutations. Recent work demonstrates that myeloid leukemia cell lines, primary AML blasts, monoblasts and monocytes, and MDS-EB-2 blasts all express LAIR-1. Critically, while high expression of LAIR-1 is characteristic of LSCs, this receptor is minimally detectable on normal HSCs, making it an ideal anti-leukemic target. NC525 is a humanized immunoglobulin gamma 1, kappa (IgG1κ) monoclonal antibody that targets LAIR-1-expressing AML blasts and LSCs. Extensive IND-enabling preclinical studies have shown the following features of NC525: (i) Inhibition of colony formation of AML CD34+ bone marrow cells; (ii) sparing of colony formation and differentiation ability of healthy CD34+ HSCs; (iii) direct ex vivo killing of AML blasts without killing healthy leukocytes; (iv) suppression of AML in both MV4-11 and THP-1 CDX models; (v) restriction of MV4-11 in a humanized murine model, without depletion or suppression of human T cells; (vi) restriction of MV4-11 tumor growth in murine blood, spleen, and bone marrow; and (vii) reduction of AML disease burden in primary patient-derived AML xenograft (PDX) models. Finally, NC525 completely inhibits leukemia propagation in secondary transplant models, suggesting that NC525 is capable of eradicating LSCs. Furthermore, NC525 destroys leukemic cells by ligation-mediated apoptosis of leukemic blasts and stem cells without evidence of an immunomodulatory effect on other immune subsets. Methods This is an open-label, non-randomized, Phase 1 dose escalation study to determine the safety and tolerability of NC525 in adult patients with advanced myeloid neoplasms. This study will also assess the clinical benefit of NC525. Eligible patients must have relapsed or refractory AML, myelodysplastic syndrome (MDS), or chronic myelomonocytic leukemia (CMML) that has progressed after standard therapy. Participants will receive NC525 by intravenous infusion on Days 1 and 15 of each 28-day cycle. During Phase 1, the safety and tolerability of NC525 will be evaluated by exploring escalating dose levels of NC525. In addition, the pharmacologically active dose (PAD), defined as the dose that provides a maximal biologic effect, such as achieving a complete remission (CR), CR with partial hematological recovery (CRh) or CR with incomplete hematological recovery (CRi), and the maximum tolerated dose (MTD) of NC525 will be determined. Safety and tolerability will be further assessed through the expansion of a few dose levels to determine an optimal recommended Phase 2 Dose (RP2D) and administration schedule of NC525, based on the PK/PD profiles. Taken together, preclinical data suggest that targeting LAIR-1 in AML and other myeloid malignancies may be an effective therapy for these diseases with the advantage of specifically eradicating leukemic stem cells and sparing normal HSCs.

EXTH-57. IDENTIFICATION OF NOVEL IMMUNE CHECKPOINT MOLECULE IN GLIOMA, LAIR1

Abstract BACKGROUND In recent years, emerging evidence indicates that tumor-associated myeloid cells (TAMCs) affect cancer progression. But the molecular mechanisms and signaling pathways involved in the TAMCs’ interaction with extracellular matrix (ECM) and tumor stroma are incompletely understood. Checkpoint inhibition therapy targets immune inhibitory receptors, such as CTLA-4 and PD-1, which have become a major weapon in fighting cancer. These antibodies demonstrate apparent advantages such as being easy to use, broad applicability, and durable clinical response. Leukocyte-Associated Immunoglobulin-like Receptor 1 (LAIR1), also called CD305, a collagen-binding immunoreceptor tyrosine-based inhibition motifs (ITIM)-bearing inhibitory receptor, was identified to present on almost all immune cell populations and overexpressed in cancers of human patients. However, LAIR1’s role and regulation in solid cancers are poorly defined. OBJECTIVE To identify LAIR1 as a new class of immune checkpoints in cancers that impacts TAMCs-associated tumor immunity. Further functional investigation warrants understanding the crosstalk between LAIR1-related immune checkpoint blocking agent(s), immune micro-environment, and its underlying mechanisms for targeted therapy development. METHODS Murine GBM cell line KR158-Luciferase cell line was used to set up the mouse model. Tumor-bearing mice were administered the Anti-LAIR1 blockade and IgG, followed by IVIS imaging for tumor growth and survival were recorded. The presentation and phenotype of immune cell populations in tumors and spleens were measured through scRNA-Seq. RESULTS GBM is one of these tumors that overexpress LAIR1 based on the TCGA analysis. LAIR1 molecules express highly on macrophages, monocytes, DCs, and activated T cells, not on the naive T cells. We found that LAIR1 blockade enhanced survival in preclinical GBM models. LAIR1 blockade reduced the presentation and function of TAMCs in tumors. What's more, LAIR1 blockade provided a synergetic antitumor effect with CD70 CAR T cells. CONCLUSION This study suggests that we identified a novel immune checkpoint molecule, LAIR1, which can limit tumor progression.

Cytotoxic T Cell Expression of Leukocyte-Associated Immunoglobulin-Like Receptor-1 (LAIR-1) in Viral Hepatitis C-Mediated Hepatocellular Carcinoma.

Virus-related hepatocellular carcinoma (HCC) pathogenesis involves liver inflammation, therefore, despite successful treatment, hepatitis C virus (HCV) may progress to HCC from initiated liver cirrhosis. Cytotoxic T cells (Tcs) are known to be involved in HCV-related cirrhotic complications and HCC pathogenesis. The inhibitory checkpoint leukocyte-associated immunoglobulin-like receptor-1 (LAIR-1) is expressed on Tcs. Therefore, we aimed to determine whether the Tc expression level of LAIR-1 is associated with HCC progression and to evaluate LAIR-1 expression as a noninvasive biomarker for HCC progression in the context of liver cirrhosis related to HCV genotype 4 (G4) in Egyptian patients’ peripheral venous blood liquid biopsy. A total of 64 patients with HCC and 37 patients with liver cirrhosis were enrolled in this case-controlled study, and their LAIR-1 expression on Tc related to the progression of liver cirrhosis was examined and compared to that of the apparently healthy control group (n = 20). LAIR-1 expression was analyzed using flow cytometry. Results: The HCC group had significantly higher LAIR-1 expression on Tc and percentage of Tc positive for LAIR-1 (LAIR-1+Tc%) than the HCV G4-related liver cirrhosis group. LAIR-1+Tc% was correlated with the HCC surrogate tumor marker AFP (r = 0.367, p = 0.001) and insulin resistance and inflammation prognostic ratios/indices. A receiver operating characteristic (ROC) curve revealed that adding LAIR-1+Tc% to AFP can distinguish HCC transformation in the Egyptian patients’ cohort. Upregulated LAIR-1 expression on Tc could be a potential screening noninvasive molecular marker for chronic inflammatory HCV G4 related liver cirrhosis. Moreover, LAIR-1 expression on Tc may be one of the players involved in the progression of liver cirrhosis to HCC.

Blocking LAIR1 signaling in immune cells inhibits tumor development.

The current immune checkpoint blockade therapy has been successful in treating some cancers but not others. New molecular targets and therapeutic approaches of cancer immunology need to be identified. Leukocyte associated immunoglobulin like receptor 1 (LAIR1) is an immune inhibitory receptor expressing on most immune cell types. However, it remains a question whether we can specifically and actively block LAIR1 signaling to activate immune responses for cancer treatment. Here we report the development of specific antagonistic anti-LAIR1 monoclonal antibodies and studied the effects of LAIR1 blockade on the anti-tumor immune functions. The anti-LAIR1 antagonistic antibody stimulated the activities of T cells, natural killer cells, macrophages, and dendritic cells in vitro. The single-cell RNA sequencing analysis of intratumoral immune cells in syngeneic human LAIR1 transgenic mice treated with control or anti-LAIR1 antagonist antibodies indicates that LAIR1 signaling blockade increased the numbers of CD4 memory T cells and inflammatory macrophages, but decreased those of pro-tumor macrophages, regulatory T cells, and plasmacytoid dendritic cells. Importantly, the LAIR1 blockade by the antagonistic antibody inhibited the activity of immunosuppressive myeloid cells and reactivated T cells from cancer patients in vitro and impeded tumor metastasis in a humanized mouse model. Blocking LAIR1 signaling in immune cells represents a promising strategy for development of anti-cancer immunotherapy.

Role of Citrullinated Collagen in Autoimmune Arthritis.

Citrullination of proteins plays an important role in protein function and it has recently become clear that citrullinated proteins play a role in immune responses. In this study we examined how citrullinated collagen, an extracellular matrix protein, affects T-cell function during the development of autoimmune arthritis. Using an HLA-DR1 transgenic mouse model of rheumatoid arthritis, mice were treated intraperitoneally with either native type I collagen (CI), citrullinated CI (cit-CI), or phosphate buffered saline (PBS) prior to induction of autoimmune arthritis. While the mice given native CI had significantly less severe arthritis than controls administered PBS, mice receiving cit-CI had no decrease in the severity of autoimmune arthritis. Using Jurkat cells expressing the inhibitory receptor leukocyte-associated immunoglobulin-like receptor-1 (LAIR-1), Western blot analysis indicated that while CI and cit-CI bound to LAIR-1 with similar affinity, only CI induced phosphorylation of the LAIR ITIM tyrosines; cit-CI was ineffective. These data suggest that cit-CI acts as an antagonist of LAIR-1 signaling, and that the severity of autoimmune arthritis can effectively be altered by targeting T cells with citrullinated collagen.

Superfast desulfurization for protein chemical synthesis and modification

Superfast desulfurization for protein chemical synthesis and modification

Development and validation of a leukocyte-associated immunoglobulin-like receptor-1 prognostic signature for lower-grade gliomas.

Leukocyte-associated immunoglobulin-like receptor-1 (LAIR-1), is an immunosuppressive receptor, widely expressed by immune cells, but the part of LAIR-1 in glioma progression remains unclear. The purpose of this study was to explore the relationship between LAIR-1 expression and the development of lower-grade glioma (LGG) using publicly available data sets. We took advantage of The Cancer Genome Atlas (TCGA) to analyze the expression of LAIR-1 in patients with LGG. Second, Kaplan-Meier methods and univariate and multivariate Cox regression analyses were used to examine the clinical significance of LAIR-1 expression in combination with CGGA databases, and then receiver operating characteristic curve analysis was used to verify the prognostic utility of LAIR-1. Gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) and gene set enrichment analysis (GSEA) were used to explore the function of LAIR-1. Analysis of the correlation with immune infiltration was conducted using the ESTIMATE algorithm and single sample gene set enrichment analysis. Our results showed that LAIR-1 expression to be positively correlated with malignant clinicopathologic features of LGG. Univariate analysis and multivariate analysis revealed that overexpression of LAIR-1 was correlated with a worse prognosis in patients. A nomogram model combining LAIR-1 was more useful in guiding clinical diagnosis, and functional enrichment analysis showed that malignant development of glioma was closely affiliated with the tumor immune microenvironment. These results indicate that LAIR 1 is a latent marker for determining the prognosis of LGG patients. LAIR 1 may also participate a critical part in TIME of LGG by regulating the infiltration of immune cells, suggesting that LAIR 1 might be used as a therapeutic target to regulate the antitumor immune response.

Remodeling the tumor microenvironment via blockade of LAIR-1 and TGF-β signaling enables PD-L1-mediated tumor eradication.

Collagens in the extracellular matrix (ECM) provide a physical barrier to tumor immune infiltration, while also acting as a ligand for immune inhibitory receptors. Transforming growth factor-β (TGF-β) is a key contributor to shaping the ECM by stimulating the production and remodeling of collagens. TGF-β activation signatures and collagen-rich environments have both been associated with T cell exclusion and lack of responses to immunotherapy. Here, we describe the effect of targeting collagens that signal through the inhibitory leukocyte-associated immunoglobulin-like receptor-1 (LAIR-1) in combination with blockade of TGF-β and programmed cell death ligand 1 (PD-L1). This approach remodeled the tumor collagenous matrix, enhanced tumor infiltration and activation of CD8+ T cells, and repolarized suppressive macrophage populations, resulting in high cure rates and long-term tumor-specific protection across murine models of colon and mammary carcinoma. The results highlight the advantage of direct targeting of ECM components in combination with immune checkpoint blockade therapy.

Structural insights into collagen binding by platelet receptor glycoprotein VI

AbstractGlycoprotein VI (GPVI) mediates collagen-induced platelet activation after vascular damage and is an important contributor to the onset of thrombosis, heart attack, and stroke. Animal models of thrombosis have identified GPVI as a promising target for antithrombotic therapy. Although for many years the crystal structure of GPVI has been known, the essential details of its interaction with collagen have remained elusive. Here, we present crystal structures of the GPVI ectodomain bound to triple-helical collagen peptides, which reveal a collagen-binding site across the β-sheet of the D1 domain. Mutagenesis and binding studies confirm the observed binding site and identify Trp76, Arg38, and Glu40 as essential residues for binding to fibrillar collagens and collagen-related peptides (CRPs). GPVI binds a site on collagen comprising two collagen chains with the core formed by the sequence motif OGPOGP. Potent GPVI-binding peptides from Toolkit-III all contain OGPOGP; weaker binding peptides frequently contain a partial motif varying at either terminus. Alanine-scanning of peptide III-30 also identified two AGPOGP motifs that contribute to GPVI binding, but steric hindrance between GPVI molecules restricts the maximum binding capacity. We further show that no cooperative interactions could occur between two GPVI monomers binding to a stretch of (GPO)5 and that binding of ≥2 GPVI molecules to a fibril-embedded helix requires non-overlapping OGPOGP motifs. Our structure confirms the previously suggested similarity in collagen binding between GPVI and leukocyte-associated immunoglobulin-like receptor 1 (LAIR-1) but also indicates significant differences that may be exploited for the development of receptor-specific therapeutics.

A Novel Prognostic Ferroptosis-Related Long Noncoding RNA Signature in Clear Cell Renal Cell Carcinoma.

Clear cell renal cell carcinoma (ccRCC) is the most common primary malignancy of renal cancer in adults. Ferroptosis is critically associated with the prognosis of ccRCC. However, knowledge of long noncoding RNA- (lncRNA-) related ferroptosis that affects the prognosis of ccRCC is still insufficient. Using the LASSO regression, we created a risk model based on differentially expressed ferroptosis-related lncRNAs (FRLRS) in ccRCC. The analysis of Kaplan–Meier for survival, area under the curve (AUC) for diagnosis, nomogram for predicting overall survival, and gene expression for immune checkpoints were performed based on the screened independent prognostic factors. Nine lncRNAs were found to be associated with ccRCC prognosis. Furthermore, the prognostic AUC of the FRLRS signature was 0.78, demonstrating its usefulness in predicting ccRCC prognosis. The lncRNA risk model outperformed the standard clinical variables in predicting ccRCC prognosis. Finally, The Cancer Genome Atlas revealed that T cell functions, such as cytolytic activity, human leukocyte antigen activity, inflammation regulation, and type II interferon response coordination, are significantly different between two different risk levels of ccRCC. Immune checkpoints were also expressed differently in programmed cell death 1 receptor, inducible T cell costimulator, cytotoxic T-lymphocyte antigen-4, and leukocyte-associated immunoglobulin-like receptor 1. The nine FRLRS signature models may affect the prognosis of ccRCC.

Increased concentration of soluble leukocyte-associated immunoglobulin-like receptor in sera from patients with blistering diseases: possible pathophysiological implications?

Autoimmune blistering diseases (AIBD), are a heterogeneous group. Despite their pathogenesis is not completely understood, autoantibodies against directed adhesion molecules of the skin and adjacent mucous membranes could play a key role. The leukocyte-associated-Ig-like-receptor (LAIR) family is a small group of immunoreceptor-tyrosine-based-inhibition-motif-containing inhibitory receptors, recognizing collagens. LAIR-1 is a transmembrane glycoprotein expressed on human-peripheral-blood-leukocytes. LAIR-2 is a secreted receptor mainly produced by CD4+ T-lymphocytes, and is able to regulate the inhibitory potential of LAIR-1. Both LAIRs have been associated with several autoimmune diseases and inflammatory responses. We evaluated circulating LAIRs in patients with different blistering skin diseases by ELISA. A significant increase of serum LAIR-2, and to a lesser extent of sLAIR-1 (with the exception of Pemphigus vulgaris), in the whole group of patients with bullous diseases, irrespective of the pathogenesis, compared to healthy controls was evident. Although the pathophysiological meaning of LAIR is not completely elucidated, the presence of increased concentration of LAIR proteins can somehow modulate the cascade of inflammatory phenomenon occurring in bullous skin diseases, in different way depending upon specific skin disease considered.

Tumor-Associated Regulatory T Cell Expression of LAIR2 Is Prognostic in Lung Adenocarcinoma.

Simple SummaryUnderstanding how the immune system navigate the tumor microenvironment is vital to developing effective drugs to treat cancer. Using gene and functional studies, we found that the collagen receptor LAIR2 is an important component of cancer regulation. When expressed in regulatory T cells, a LAIR2 containing gene signature is adversely prognostic in lung cancer. This study highlights the importance of microenvironment regulation of immune cells and provides a unique target for future therapeutic development.Cancer development requires a permissive microenvironment that is shaped by interactions between tumor cells, stroma, and the surrounding matrix. As collagen receptors, the leukocyte-associated immunoglobulin-like receptor (LAIR) family allows the immune system to interact with the extracellular matrix. However, little is known about their role in regulating tumor immunity and cancer progression. Methods: Genetic analysis of resected human lung adenocarcinoma was correlated to clinical-pathological characteristics, gene ontologies, and single cell RNA sequencing (scRNASeq). LAIR2 production was determined in subsets of immune cells isolated from blood leukocytes and lung adenocarcinoma tumor. Functional assays were used to determine the role of LAIR2 in tumorigenesis. Results: LAIR2 expression was adversely prognostic in lung adenocarcinoma. LAIR2 was preferentially produced by activated CD4+ T cells and enhanced in vitro tumor invasion into collagen. scRNASeq analysis of tumor infiltrating T cells revealed that LAIR2 expression co-localized with FOXP3 expressing cells and shared a transcriptional signature with tumor-associated regulatory T (Treg) cells. A CD4+ LAIR2+ Treg gene signature was prognostically significant in the TCGA dataset (n = 439; hazard ratio (HR) = 1.37; 95% confidence interval (CI), 1.05–1.77, p = 0.018) and validated in NCI Director’s Challenge lung adenocarcinoma dataset (n = 488; HR = 1.54; 95% CI, 1.14–2.09, p = 0.0045). Conclusions: Our data support a role for LAIR2 in lung adenocarcinoma tumorigenesis and identify a CD4+ LAIR2+ Treg gene signature in lung adenocarcinoma prognosis. LAIR2 provides a novel target for development of immunotherapies.

Collagen Fragments Produced in Cancer Mediate T Cell Suppression Through Leukocyte-Associated Immunoglobulin-Like Receptor 1.

The tumor microenvironment (TME) is a complex structure comprised of tumor, immune and stromal cells, vasculature, and extracellular matrix (ECM). During tumor development, ECM homeostasis is dysregulated. Collagen remodeling by matrix metalloproteinases (MMPs) generates specific collagen fragments, that can be detected in the circulation of cancer patients and correlate with poor disease outcome. Leukocyte-Associated Immunoglobulin-like Receptor-1 (LAIR-1) is an inhibitory collagen receptor expressed on immune cells in the TME and in the circulation. We hypothesized that in addition to ECM collagen, collagen fragments produced in cancer can mediate T cell immunosuppression through LAIR-1. Our analyses of TCGA datasets show that cancer patients with high tumor mRNA expression of MMPs, collagen I and LAIR-1 have worse overall survival. We show that in vitro generated MMP1 or MMP9 collagen I fragments bind to and trigger LAIR-1. Importantly, LAIR-1 triggering by collagen I fragments inhibits CD3 signaling and IFN-γ secretion in a T cell line. LAIR-2 is a soluble homologue of LAIR-1 with higher affinity for collagen and thereby acts as a decoy receptor. Fc fusion proteins of LAIR-2 have potential as cancer immunotherapeutic agents and are currently being tested in clinical trials. We demonstrate that collagen fragment-induced inhibition of T cell function could be reversed by LAIR-2 fusion proteins. Overall, we show that collagen fragments produced in cancer can mediate T cell suppression through LAIR-1, potentially contributing to systemic immune suppression. Blocking the interaction of LAIR-1 with collagen fragments could be an added benefit of LAIR-1-directed immunotherapy.

Type I interferon autoantibodies are associated with systemic immune alterations in patients with COVID-19.

Neutralizing autoantibodies against type I interferons (IFNs) have been found in some patients with critical coronavirus disease 2019 (COVID-19), the disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, the prevalence of these antibodies, their longitudinal dynamics across the disease severity scale, and their functional effects on circulating leukocytes remain unknown. Here, in 284 patients with COVID-19, we found type I IFN–specific autoantibodies in peripheral blood samples from 19% of patients with critical disease and 6% of patients with severe disease. We found no type I IFN autoantibodies in individuals with moderate disease. Longitudinal profiling of over 600,000 peripheral blood mononuclear cells using multiplexed single-cell epitope and transcriptome sequencing from 54 patients with COVID-19 and 26 non–COVID-19 controls revealed a lack of type I IFN–stimulated gene (ISG-I) responses in myeloid cells from patients with critical disease. This was especially evident in dendritic cell populations isolated from patients with critical disease producing type I IFN–specific autoantibodies. Moreover, we found elevated expression of the inhibitory receptor leukocyte-associated immunoglobulin-like receptor 1 (LAIR1) on the surface of monocytes isolated from patients with critical disease early in the disease course. LAIR1 expression is inversely correlated with ISG-I expression response in patients with COVID-19 but is not expressed in healthy controls. The deficient ISG-I response observed in patients with critical COVID-19 with and without type I IFN–specific autoantibodies supports a unifying model for disease pathogenesis involving ISG-I suppression through convergent mechanisms.

Adiponectin's globular domain inhibits T cell activation by interacting with LAIR-1

Adiponectin (APN) is the most abundant adipokine in human plasma, and has insulin-sensitizing effect. Recent studies have reported that APN plays both anti- and pro-inflammatory roles under different circumstances. However, there is a lack of convincing evidence that decipher APN's anti-inflammatory role through the known receptors and their downstream signaling pathways. In this study, we evaluated a new molecular mechanism underlying APN's anti-inflammatory roles. Our results revealed that the globular domain of adiponectin (gAdp) interacted with the inhibitory leukocyte-associated immunoglobulin-like receptor-1 (LAIR-1). In vitro experiments showed that gAdp inhibited activation of the T cells via the LAIR-1, through a process that also involved downstream SHP-2. These findings indicate that LAIR-1 is a novel APN receptor, affirming APN's anti-inflammatory effect. In summary, we have identified a novel mechanism of peripheral immunoregulatory processes that provides baseline information for further studies on gAdp's role and its contribution to inflammation.

Expression and clinical significance of inhibitory receptor Leukocyte-associated immunoglobulin-like receptor-1 on peripheral blood T cells of chronic hepatitis B patients: A cross-sectional study.

Leukocyte-associated immunoglobulin-like receptor-1 (LAIR-1) is an inhibitory receptor that is expressed on the surface of multiple immune cells and plays key roles in immune modulation. In patients with chronic hepatitis B (CHB), T cell number and functions are abnormal and the expression of inhibitory receptors is elevated. However, the expression of LAIR-1 on T cells in patients with CHB is still undetermined.We recruited 320 patients with CHB in different disease phases and 17 healthy donors. Serum biochemical and virological examinations were performed for each participant, and their demographic and clinical data were collected. According to the latest American Association for the Study of Liver Disease guidelines, we categorized the patients into 4 groups: immune active, immune tolerant, inactive CHB, and gray zone. Additionally, we tested the expression of LAIR-1 on T cells and T cell subsets using flow cytometry.We observed a significant decrease in LAIR-1 expression on CD3+ T cells and its two subsets (CD4+ and CD8+ T cells) in patients with CHB. LAIR-1 expression on T cells was the lowest in the immune active group. LAIR-1 expression levels on CD4+ and CD8+ T cells showed a significant negative association with hepatitis B virus (HBV) DNA load and were lower in hepatitis B e antigen (HBeAg)-positive patients than in HBeAg-negative patients (P < .05). In addition, LAIR-1 expression levels on CD3+, CD4+, and CD8+ T cells were all negatively associated with liver inflammation and fibrosis parameters, such as alanine aminotransferase and aspartate aminotransferase levels, FibroScan value, and aspartate aminotransferase-to-platelet ratio index score.LAIR-1 expression levels on T cells were associated with HBV DNA load and liver inflammation and fibrosis parameters, indicating that LAIR-1 may play an important regulatory role in HBV-induced T cell immune pathogenesis and may be a therapeutic target for CHB.