CD24: a genetic checkpoint in T cell homeostasis and autoimmune diseases

Effects of conceptus proteins on endometrium and blood leukocytes of dairy cattle using transcriptome and meta-analysis

This study investigates the short and long-term effects of IFNT and PAG on the transcriptome of endometrium and blood leukocytes. Holstein heifers received intrauterine infusions of one of the following treatments: 20 mL of a 200 μg/mL bovine serum albumin solution (BSA; vehicle) from day 14 to 16 of the estrous cycle (BSA), vehicle + 10 μg/mL of IFNT from day 14 to 16 (IFNT3), vehicle + 10 μg/mL of IFNT from day 14 to 19 (IFNT6), and vehicle + 10 μg/mL of IFNT from day 14 to 16 followed by vehicle + 10 μg/mL of IFNT + 5 μg/mL of PAG from day 17 to 19 (IFNT+PAG). RNA-seq analysis was performed in endometrial biopsies and blood leukocytes collected after treatments. Acute IFNT signaling in the endometrium (IFNT3 vs BSA), induced differentially expressed genes (DEG) associated with interferon activation, immune response, inflammation, cell death, and inhibited vesicle transport and extracellular matrix remodeling. Prolonged IFNT signaling (IFNT6 vs IFNT3) altered gene expression related to cell invasion, retinoic acid signaling, and embryo implantation. In contrast, PAG induced numerous DEG in blood leukocytes but only 4 DEG in the endometrium. In blood leukocytes, PAG stimulated genes involved in development and TGFB signaling while inhibiting interferon signaling and cell migration. Overall, IFNT is a primary regulator of endometrial gene expression, while PAG predominantly affected the transcriptome of circulating immune cells during early pregnancy. Further research is essential to fully grasp the roles of identified DEG in both the endometrium and blood leukocytes.

The safety and potential efficacy of exosomes overexpressing CD24 (EXO-CD24) in mild-moderate COVID-19 related ARDS

INTRODUCTION

EXO-CD24 are exosomes genetically manipulated to over-express Cluster of Differentiation (CD) 24. It consists of two breakthrough technologies: CD24, the drug, as a novel immunomodulator that is smarter than steroids without any side effects, and exosomes as the ideal natural drug carrier.

METHODS

A randomized, single blind, dose-finding phase IIb trial in hospitalized patients with mild to moderate Coronavirus disease 2019 (COVID-19) related Acute Respiratory Distress Syndrome (ARDS) was carried out in two medical centers in Athens. Patients received either 109 or 1010 exosome particles of EXO-CD24, daily, for five consecutive days and monitored for 28 days. Efficacy was assessed at day 7 among 91 patients who underwent randomization. The outcome was also compared in a post-hoc analysis with an income control group (n = 202) that fit the inclusion and exclusion criteria.

RESULTS

The mean age was 49.4 (± 13.2) years and 74.4% were male. By day 7, 83.7% showed improved respiratory signs and 64% had better oxygen saturation (SpO2) (p < 0.05). There were significant reductions in all inflammatory markers, most notably in C-reactive protein (CRP), lactate dehydrogenase (LDH), ferritin, fibrinogen and an array of cytokines. Conversely, levels of the anti-inflammatory cytokine Interleukin-10 (IL-10) were increased (p < 0.05). Of all the documented adverse events, none were considered treatment related. No drug-drug interactions were noted. Two patients succumbed to COVID-19. Post-hoc analysis revealed that EXO-CD24 patients exhibited greater improvements in clinical and laboratory outcomes compared to an observational income control group.

CONCLUSIONS

EXO-CD24 presents a promising therapeutic approach for hyper-inflammatory state and in particular ARDS. Its unique combination of exosomes, as a drug carrier, and CD24, as an immunomodulator, coupled with inhalation administration, warrants further investigation in a larger, international, randomized, quadri-blind trial against a placebo.

Unraveling the role of CD24 in Hepatocellular carcinoma: Involvement of inactivated Hippo signaling and SOX4-mediated regulation

Hepatocellular carcinoma (HCC) is a prevalent type of liver cancer, and CD24 gene is reportedly involved in HCC progression. However, the precise regulatory mechanisms of CD24 in HCC remain unclear. In this study, we established a primary HCC mouse model and observed that CD24, induced by inactivation of the Hippo pathway, was highly expressed in HCC. Using a systematic molecular and genomic approach, we identified the Hippo-YAP1-SOX4 pathway as the mechanism through which YAP1 induces CD24 upregulation in HCC cells. CD24 knockdown significantly attenuated YAP1 activation-induced HCC. These findings shed light on the link between CD24 and HCC progression, particularly in the Hippo-inactivated subclass of HCC. Therefore, CD24 may serve as a potential target for specific treatment of this HCC subclass.

A phase 2 trial of CD24Fc for prevention of graft-versus-host disease

ABSTRACT

Patients who undergo human leukocyte antigen-matched unrelated donor (MUD) allogeneic hematopoietic stem cell transplantation (HSCT) with myeloablative conditioning for hematologic malignancies often develop acute graft-versus-host disease (GVHD) despite standard calcineurin inhibitor-based prophylaxis in combination with methotrexate. This trial evaluated a novel human CD24 fusion protein (CD24Fc/MK-7110) that selectively targets and mitigates inflammation due to damage-associated molecular patterns underlying acute GVHD while preserving protective immunity after myeloablative conditioning. This phase 2a, multicenter study evaluated the pharmacokinetics, safety, and efficacy of CD24Fc in combination with tacrolimus and methotrexate in preventing acute GVHD in adults undergoing MUD HSCT for hematologic malignancies. A double-blind, placebo-controlled, dose-escalation phase to identify a recommended dose was followed by an open-label expansion phase with matched controls to further evaluate the efficacy and safety of CD24Fc in preventing acute GVHD. A multidose regimen of CD24Fc produced sustained drug exposure with similar safety outcomes when compared with single-dose regimens. Grade 3 to 4 acute GVHD-free survival at day 180 was 96.2% (95% confidence interval [CI], 75.7-99.4) in the CD24Fc expansion cohort (CD24Fc multidose), compared with 73.6% (95% CI, 63.2-81.4) in matched controls (hazard ratio, 0.1 [95% CI, 0.0-0.6]; log-rank test, P = .03). No participants in the CD24Fc escalation or expansion phases experienced dose-limiting toxicities (DLTs). The multidose regimen of CD24Fc was well tolerated with no DLTs and was associated with high rates of severe acute GVHD-free survival after myeloablative MUD HSCT. This trial was registered at ClinicalTrials.gov as #NCT02663622.

Inhaled CD24-Enriched Exosomes (EXO-CD24) as a Novel Immune Modulator in Respiratory Disease

Acute Respiratory Distress Syndrome (ARDS) is a major health concern with urgent unmet need for treatment options. There are three million new ARDS cases annually, and the disease's mortality rate is high (35-46%). Cluster of differentiation 24 (CD24), a long-known protein with multifaceted functions, is a small, heavily glycosylated, membrane-anchored protein which functions as an immune checkpoint control. CD24 allows for immune discrimination between Damage-Associated Molecular Patterns and Pathogen-Associated Molecular Patterns derived from pathogens. Exosomes are intraluminal vesicles which play an important role in intercellular communication. Exosomes offer the advantage of targeted delivery, which improves safety and efficacy. The safety and efficacy of EXO-CD24 is promising, as was shown in >180 ARDS patients in phase 1b/2a, phase 2b, and compassionate use. CD24 binds Damage-associated molecular patterns (DAMPs) and inhibits the activation of the NF-ĸB pathway, a pivotal mediator of inflammatory responses. In contrast to anti-inflammatory therapies that are cytokine-specific or steroids that shut down the entire immune system, EXO-CD24 acts upstream, reverting the immune system back to normal activity. Herein, the safety and efficacy of mEXO-CD24 is shown in murine models of several pulmonary diseases (sepsis, allergic asthma, Chronic Obstructive Pulmonary Disease(COPD), fibrosis). EXO CD24 can suppress the hyperinflammatory response in the lungs in several pulmonary diseases with a significant unmet need for treatment options.

Inhaled Exosomes Genetically Manipulated to Overexpress CD24 (EXO-CD24) as a Compassionate Use in Severe ARDS Patients

RATIONALE

Acute respiratory distress syndrome (ARDS) is a major global health concern with a significant unmet need. EXO-CD24 is delivered via inhalation-reduced cytokines and chemokine secretion and lung injury in ARDS and improved survival in mice models of ARDS, influenza, and sepsis.

OBJECTIVES

This clinical paper aims to evaluate the potential of EXO-CD24, a novel immunomodulatory treatment, in the compassionate care of critically ill, intubated patients with post-infection-induced acute respiratory distress syndrome (ARDS).

METHODS

Eleven critically ill patients diagnosed with post-infection ARDS (10 with COVID-19 and one with an adenovirus-associated infection) were administered EXO-CD24 in four medical centers across Israel. The patients had multiple co-morbidities, including cancer, hypertension, diabetes, and ischemic heart disease, and met the criteria for severe ARDS according to the Berlin classification. EXO-CD24 was administered via inhalation, and adverse events related to its use were carefully monitored.

MEASUREMENTS AND MAIN RESULTS

The administration of EXO-CD24 did not result in any recorded adverse events. The median hospitalization duration was 11.5 days, and the overall mortality rate was 36%. Notably, patients treated at the Tel Aviv Medical Center (TASMC) showed a lower mortality rate of 12.5%. The WBC and CRP levels decreased in comparison to baseline levels at hospitalization, and rapid responses occurred even in patients with kidney transplants who were off the ventilator within a few days and discharged shortly thereafter. The production of cytokines and chemokines was significantly suppressed in all patients, including those who died. Among the patients at TASMC, four had kidney transplants and were on immunosuppressive drugs, and all of them fully recovered and were discharged from the hospital.

CONCLUSIONS

EXO-CD24 holds promise as a potential therapeutic agent for all stages of ARDS, even in severe intubated cases. Importantly, EXO-CD24 demonstrated a favorable safety profile without any apparent side effects with promising efficacy. Furthermore, the potential of EXO-CD24 as a platform for addressing hyper-inflammatory states warrants exploration. Further research and larger-scale clinical trials are warranted to validate these preliminary findings.

Soluble CD24 is an inflammatory biomarker in early and seronegative rheumatoid arthritis

Introduction: Rheumatoid arthritis (RA) is a chronic, systemic autoimmune disease characterized by autoantibody production, joint inflammation and bone destruction. Nearly 1/3 of RA patients with the active disease also exhibit a normal range of ESR and CRP. Here we assessed the performance and clinical significance of soluble CD24 (sCD24) as a biomarker of disease activity in RA.Methods: A total of 269 RA patients, 59 primary Sjogren's syndrome (SS) patients, 81 systematic lupus erythematosus (SLE) patients, 76 osteoarthritis (OA) patients and 97 healthy individuals (HC) were included in this study. Soluble CD24 in sera were detected by ELISA. Therefore, the concentration of sCD24 was analyzed in RA patients with different disease activity statuses.Results: The sCD24 was significantly increased in RA (2970 pg/mL), compared to other rheumatic diseases (380-520 pg/mL) and healthy individuals (320 pg/mL). Moreover, sCD24 was elevated in 66.67% of early RA and 61.11% of seronegative RA patients. In addition, sCD24 was significantly correlated with the disease duration and inflammatory indicators.Conclusion: The sCD24 could be an inflammatory biomarker in RA patients, especially in early and seronegative patients.

Modeling Preeclampsia In Vitro: Polymorphic Variants of STOX1-A/B Genes Can Downregulate CD24 in Trophoblast Cell Lines

CD24 is a mucin-like immunosuppressing glycoprotein whose levels increase during pregnancy and decrease in the syncytio- and cytotrophoblasts in early and preterm preeclampsia. We used two modified cell lines that mimic in vitro features of preeclampsia to identify if this phenomenon could be reproduced. Our model was the immortalized placental-derived BeWo and JEG-3 cell lines that overexpress the STOX1 A/B transcription factor gene that was discovered in familial forms of preeclampsia. BeWo and JEG-3 cells stably transduced with the two major isoforms of STOX1-A/B or by an empty vector (control), were propagated, harvested, and analyzed. CD24 mRNA expression was determined by quantitative real-time polymerase nuclear chain reaction (qRT-PCR). CD24 protein levels were determined by Western blots. In STOX1-A/B overexpressing in BeWo cells, CD24 mRNA was downregulated by 91 and 85%, respectively, compared to the control, and by 30% and 74%, respectively in JEG-3 cells. A 67% and 82% decrease in CD24 protein level was determined by immunoblot in BeWo overexpressing STOX1-A/B, respectively, while the reduction in JEG-3 cells was between 47 and 62%. The immortalized BeWo and JEG-3 cell lines overexpressing STOX1-A/B had reduced CD24. Although both cell lines were affected, BeWo appears to be more susceptible to downregulation by STOX-1 than JEG-3, potentially because of their different cell origin and properties. These results strengthen the in vivo results of reduced CD24 levels found in early and preterm preeclampsia. Accordingly, it implies the importance of the reduced immune tolerance in preeclampsia, which was already demonstrated in vivo in the STOX1-A/B model of preeclampsia, and is now implied in the in vitro STOX-1 model, a subject that warrants further investigations.

Treatment with soluble CD24 attenuates COVID-19-associated systemic immunopathology

Background

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) causes coronavirus disease 2019 (COVID-19) through direct lysis of infected lung epithelial cells, which releases damage-associated molecular patterns and induces a pro-inflammatory cytokine milieu causing systemic inflammation. Anti-viral and anti-inflammatory agents have shown limited therapeutic efficacy. Soluble CD24 (CD24Fc) blunts the broad inflammatory response induced by damage-associated molecular patterns via binding to extracellular high mobility group box 1 and heat shock proteins, as well as regulating the downstream Siglec10-Src homology 2 domain–containing phosphatase 1 pathway. A recent randomized phase III trial evaluating CD24Fc for patients with severe COVID-19 (SAC-COVID; NCT04317040) demonstrated encouraging clinical efficacy.

Methods

Using a systems analytical approach, we studied peripheral blood samples obtained from patients enrolled at a single institution in the SAC-COVID trial to discern the impact of CD24Fc treatment on immune homeostasis. We performed high dimensional spectral flow cytometry and measured the levels of a broad array of cytokines and chemokines to discern the impact of CD24Fc treatment on immune homeostasis in patients with COVID-19.

Results

Twenty-two patients were enrolled, and the clinical characteristics from the CD24Fc vs. placebo groups were matched. Using high-content spectral flow cytometry and network-level analysis, we found that patients with severe COVID-19 had systemic hyper-activation of multiple cellular compartments, including CD8⁺ T cells, CD4⁺ T cells, and CD56⁺ natural killer cells. Treatment with CD24Fc blunted this systemic inflammation, inducing a return to homeostasis in NK and T cells without compromising the anti-Spike protein antibody response. CD24Fc significantly attenuated the systemic cytokine response and diminished the cytokine coexpression and network connectivity linked with COVID-19 severity and pathogenesis.

Conclusions

Our data demonstrate that CD24Fc rapidly down-modulates systemic inflammation and restores immune homeostasis in SARS-CoV-2-infected individuals, supporting further development of CD24Fc as a novel therapeutic against severe COVID-19.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13045-021-01222-y.

IMMUNOLOGICAL INSIGHTS INTO THE THERAPEUTIC ROLES OF CD24Fc AGAINST SEVERE COVID-19

BACKGROUND.

SARS-CoV-2 causes COVID-19 through direct lysis of infected lung epithelial cells, which releases damage-associated molecular patterns (DAMPs) and induces a pro-inflammatory cytokine milieu causing systemic inflammation. Anti-viral and anti-inflammatory agents have shown limited therapeutic efficacy. Soluble CD24 (CD24Fc) is able to blunt the broad inflammatory response induced by DAMPs in multiple models. A recent randomized phase III trial evaluating the impact of CD24Fc in patients with severe COVID-19 demonstrated encouraging clinical efficacy.

METHODS.

We studied peripheral blood samples obtained from patients enrolled at a single institution in the SAC-COVID trial (NCT04317040) collected before and after treatment with CD24Fc or placebo. We performed high dimensional spectral flow cytometry analysis of peripheral blood mononuclear cells and measured the levels of a broad array of cytokines and chemokines. A systems analytical approach was used to discern the impact of CD24Fc treatment on immune homeostasis in patients with COVID-19.

FINDINGS.

Twenty-two patients were enrolled, and the clinical characteristics from the CD24Fc vs. placebo groups were matched. Using high-content spectral flow cytometry and network-level analysis, we found systemic hyper-activation of multiple cellular compartments in the placebo group, including CD8⁺ T cells, CD4⁺ T cells, and CD56⁺ NK cells. By contrast, CD24Fc-treated patients demonstrated blunted systemic inflammation, with a return to homeostasis in both NK and T cells within days without compromising the ability of patients to mount an effective anti-Spike protein antibody response. A single dose of CD24Fc significantly attenuated induction of the systemic cytokine response, including expression of IL-10 and IL-15, and diminished the coexpression and network connectivity among extensive circulating inflammatory cytokines, the parameters associated with COVID-19 disease severity.

INTERPRETATION.

Our data demonstrates that CD24Fc treatment rapidly down-modulates systemic inflammation and restores immune homeostasis in SARS-CoV-2-infected individuals, supporting further development of CD24Fc as a novel therapeutic against severe COVID-19.

FUNDING.

NIH

Reduced Placental CD24 in Preterm Preeclampsia Is an Indicator for a Failure of Immune Tolerance

INTRODUCTION

CD24 is a mucin-like glycoprotein expressed at the surface of hematopoietic and tumor cells and was recently shown to be expressed in the first trimester placenta. As it was postulated as an immune suppressor, CD24 may contribute to maternal immune tolerance to the growing fetus. Preeclampsia (PE), a major pregnancy complication, is linked to reduced immune tolerance. Here, we explored the expression of CD24 in PE placenta in preterm and term cases.

METHODS

Placentas were derived from first and early second trimester social terminations (N = 43), and third trimester normal term delivery (N = 67), preterm PE (N = 18), and preterm delivery (PTD) (N = 6). CD24 expression was determined by quantitative polymerase chain reaction (qPCR) and Western blotting. A smaller cohort included 3-5 subjects each of term and early PE, and term and preterm delivery controls analyzed by immunohistochemistry.

RESULTS

A higher expression (2.27-fold) of CD24 mRNA was determined in the normal term delivery compared to first and early second trimester cases. The mRNA of preterm PE cases was only higher by 1.31-fold compared to first and early second trimester, while in the age-matched PTD group had a fold increase of 5.72, four times higher compared to preterm PE. The delta cycle threshold (ΔCt) of CD24 mRNA expression in the preterm PE group was inversely correlated with gestational age (r = 0.737) and fetal size (r = 0.623), while correlation of any other group with these parameters was negligible. Western blot analysis revealed that the presence of CD24 protein in placental lysate of preterm PE was significantly reduced compared to term delivery controls (p = 0.026). In immunohistochemistry, there was a reduction of CD24 staining in villous trophoblast in preterm PE cases compared to gestational age-matched PTD cases (p = 0.042). Staining of PE cases at term was approximately twice higher compared to preterm PE cases (p = 0.025) but not different from normal term delivery controls.

CONCLUSION

While higher CD24 mRNA expression levels were determined for normal term delivery compared to earlier pregnancy stages, this expression level was found to be lower in preterm PE cases, and could be said to be linked to reduced immune tolerance in preeclampsia.

Phenotypic Characterization by Mass Cytometry of the Microenvironment in Ovarian Cancer and Impact of Tumor Dissociation Methods

Simple Summary

High-grade serous ovarian cancer (HGSOC) is the deadliest gynecological malignancy. Despite increasing research on HGSOC, biomarkers for individualized selection of therapy are scarce. In this study, we develop a multiparametric mass cytometry antibody panel to identify differences in the cellular composition of the microenvironment of tumor tissues dissociated to single-cell suspensions. We also investigate how dissociation methods impact results. Application of our antibody panel to HGSOC tissues showed its ability to identify established main cell subsets and subpopulations of these cells. Comparisons between dissociation methods revealed differences in cell fractions for one immune, two stromal, and three tumor cell subpopulations, while functional marker expression was not affected by the dissociation method. The interpatient disparities identified in the tumor microenvironment were more significant than those identified between differently dissociated tissues from one patient, indicating that the panel facilitates the mapping of individual tumor microenvironments in HGSOC patients.

Abstract

Improved molecular dissection of the tumor microenvironment (TME) holds promise for treating high-grade serous ovarian cancer (HGSOC), a gynecological malignancy with high mortality. Reliable disease-related biomarkers are scarce, but single-cell mapping of the TME could identify patient-specific prognostic differences. To avoid technical variation effects, however, tissue dissociation effects on single cells must be considered. We present a novel Cytometry by Time-of-Flight antibody panel for single-cell suspensions to identify individual TME profiles of HGSOC patients and evaluate the effects of dissociation methods on results. The panel was developed utilizing cell lines, healthy donor blood, and stem cells and was applied to HGSOC tissues dissociated by six methods. Data were analyzed using Cytobank and X-shift and illustrated by t-distributed stochastic neighbor embedding plots, heatmaps, and stacked bar and error plots. The panel distinguishes the main cellular subsets and subpopulations, enabling characterization of individual TME profiles. The dissociation method affected some immune (n = 1), stromal (n = 2), and tumor (n = 3) subsets, while functional marker expressions remained comparable. In conclusion, the panel can identify subsets of the HGSOC TME and can be used for in-depth profiling. This panel represents a promising profiling tool for HGSOC when tissue handling is considered.

Evaluation of two functional CD24 polymorphisms in primary sclerosing cholangitis

Background: Primary sclerosing cholangitis (PSC) is a progressive liver disease and characterized by chronic inflammation, sclerosis and strictures of bile ducts. Several genetic risk factors might contribute to pathogenesis. Functional single nucleotide polymorphisms (SNPs) in the CD24 gene have been associated with the development of autoimmune and autoinflammatory diseases and might contribute to the susceptibility for inflammatory bowel disease (IBD).Aim: This retrospective study aimed to evaluate the impact of two functional CD24 SNPs on clinical features and disease progression in patients with PSC.Methods: A C to T coding polymorphism (rs8734) and a TG deletion in the 3´- untranslated region (rs3838646) were genotyped. The study cohort comprises of 359 PSC patients for rs3838646 genotype and 335 PSC patients for rs8734 genotype. Clinical and laboratory parameters were collected by chart review.Results: For the rs8734 genotype, 175 patients (52.2%) were found to be homozygous wildtype ('Ala/Ala'), 127 (37.9%) patients were heterozygous ('Ala/Val') and 33 patients (9.9%) were homozygous mutant ('Val/Val'). The rs8734genotype was associated with a decreased risk for dominant strictures at first diagnosis of PSC (p = .04). For the rs3838646 genotype, 322 patients (89.7%) were found to be homozygous wildtype ('TG/TG'); 37 showed the 'TG/del' genotype (10.3%). The 'TG/del'genotype was associated with alower risk of IBD (p = .01).There was no influence of both CD24 SNPs with clinical end points or transplantation-free survival in our PSC cohort.Conclusion: Our results suggest a mild association of the rs8734 CD24 genotype with dominant strictures at first diagnosis of PSC. The rs3838646 CD24 genotype is associated with a lower rate of IBD. Both SNPs seem to modulate the clinical phenotype without major pathogenetic importance for disease progression in PSC.

Distinct molecular etiologies of male and female hepatocellular carcinoma

BACKGROUND

Sex-differences in cancer occurrence and mortality are evident across tumor types; men exhibit higher rates of incidence and often poorer responses to treatment. Targeted approaches to the treatment of tumors that account for these sex-differences require the characterization and understanding of the fundamental biological mechanisms that differentiate them. Hepatocellular Carcinoma (HCC) is the second leading cause of cancer death worldwide, with the incidence rapidly rising. HCC exhibits a male-bias in occurrence and mortality, but previous studies have failed to explore the sex-specific dysregulation of gene expression in HCC.

METHODS

Here, we characterize the sex-shared and sex-specific regulatory changes in HCC tumors in the TCGA LIHC cohort using combined and sex-stratified differential expression and eQTL analyses.

RESULTS

By using a sex-specific differential expression analysis of tumor and tumor-adjacent samples, we uncovered etiologically relevant genes and pathways differentiating male and female HCC. While both sexes exhibited activation of pathways related to apoptosis and cell cycle, males and females differed in the activation of several signaling pathways, with females showing PPAR pathway enrichment while males showed PI3K, PI3K/AKT, FGFR, EGFR, NGF, GF1R, Rap1, DAP12, and IL-2 signaling pathway enrichment. Using eQTL analyses, we discovered germline variants with differential effects on tumor gene expression between the sexes. 24.3% of the discovered eQTLs exhibit differential effects between the sexes, illustrating the substantial role of sex in modifying the effects of eQTLs in HCC. The genes that showed sex-specific dysregulation in tumors and those that harbored a sex-specific eQTL converge in clinically relevant pathways, suggesting that the molecular etiologies of male and female HCC are partially driven by differential genetic effects on gene expression.

CONCLUSIONS

Sex-stratified analyses detect sex-specific molecular etiologies of HCC. Overall, our results provide new insight into the role of inherited genetic regulation of transcription in modulating sex-differences in HCC etiology and provide a framework for future studies on sex-biased cancers.

The role of CD24 in multiple myeloma tumorigenicity and effects of the microenvironment on its expression

Multiple myeloma (MM) is an incurable neoplasm characterized by infiltration of malignant plasma cells (PCs). Recently, the tumor microenvironment has become of great interest in MM as it known to be involved in progression and metastasis of the disease. CD24, is an adhesion molecule expressed during B cell maturation, is down regulated through the cells differentiation into PCs. Though the role of CD24 in solid cancers is well defined, its role in MM remains unknown. We aimed to understand the involvement of CD24 in MM by up-regulating its expression on MM cell lines by co-culturing the cells with bone marrow stromal cell (BMSCs). We then studied the differences between CD24+ and CD24− MM cells and found that CD24+ MM cells presented a less tumorigenic phenotype by impaired capability to migrate and to create colonies as compared with CD24− MM cells. Furthermore, there were significantly more apoptotic cells in the CD24+ fraction. Additionally, the CD24+ cells also upregulated CXCR4 expression. The decrease tumorigenicity correlated with a “more normal” PC immunophenotype in patients with MM and correlated with CD45 expression and a stronger expression of CXCR4. In summary, we found the expression of CD24 on PCs to correlate with attenuated tumorigenicity.

Amplification of the CD24 Gene Is an Independent Predictor for Poor Prognosis of Breast Cancer

CD24 is a glycosyl-phosphatidyl-inositol linked glycoprotein expressed in a broad range of cell types including cancer cells. Although it is overexpressed in nearly 70% of human cancers, copy number variation of the CD24 locus has not been reported for any cancer. Here, we analyzed the genomics, transcriptomics, and clinical data of 1082 breast cancer (BRCA) samples and other cancer samples from the clinically annotated genomic database, The Cancer Genome Atlas (TCGA). The GISTIC2 method was applied to stratify the CD24 copy number, and Cox regression was performed to compare hazard ratio (HR) of CD24 overexpression, amplification and other traditional prognosis features for overall survival (OS). Our data demonstrated that CD24 amplification strongly correlated with its mRNA overexpression as well as TP53 mutant, cancer proliferation and metastasis features. In particular, CD24 amplification was enriched in basal-like subtype samples and associated with poor clinical outcome. Surprisingly, based on the univariate Cox regression analysis, CD24 overexpression (HR = 1.62, P = 0.010) and copy number amplification (HR = 1.79, P = 0.022) was more relevant to OS than TP53 mutant, mutation counts, diagnosis age, and BRCA subtypes. And based on multivariate survival analysis, CD24 amplification remained the most significant and independent predictor for worse OS (HR = 1.88, P = 0.015).

Uncoupling therapeutic from immunotherapy-related adverse effects for safer and effective anti-CTLA-4 antibodies in CTLA4 humanized mice

Anti-CTLA-4 monoclonal antibodies (mAbs) confer a cancer immunotherapeutic effect (CITE) but cause severe immunotherapy-related adverse events (irAE). Targeting CTLA-4 has shown remarkable long-term benefit and thus remains a valuable tool for cancer immunotherapy if the irAE can be brought under control. An animal model, which recapitulates clinical irAE and CITE, would be valuable for developing safer CTLA-4-targeting reagents. Here, we report such a model using mice harboring the humanized Ctla4 gene. In this model, the clinically used drug, Ipilimumab, induced severe irAE especially when combined with an anti-PD-1 antibody; whereas another mAb, L3D10, induced comparable CITE with very mild irAE under the same conditions. The irAE corresponded to systemic T cell activation and resulted in reduced ratios of regulatory to effector T cells (Treg/Teff) among autoreactive T cells. Using mice that were either homozygous or heterozygous for the human allele, we found that the irAE required bi-allelic engagement, while CITE only required monoallelic engagement. As with the immunological distinction for monoallelic vs bi-allelic engagement, we found that bi-allelic engagement of the Ctla4 gene was necessary for preventing conversion of autoreactive T cells into Treg cells. Humanization of L3D10, which led to loss of blocking activity, further increased safety without affecting the therapeutic effect. Taken together, our data demonstrate that complete CTLA-4 occupation, systemic T cell activation and preferential expansion of self-reactive T cells are dispensable for tumor rejection but correlate with irAE, while blocking B7-CTLA-4 interaction impacts neither safety nor efficacy of anti-CTLA-4 antibodies. These data provide important insights for the clinical development of safer and potentially more effective CTLA-4-targeting immunotherapy.

CD24-p53 axis suppresses diethylnitrosamine-induced hepatocellular carcinogenesis by sustaining intrahepatic macrophages

It is generally assumed that inflammation following diethylnitrosamine (DEN) treatment promotes development of hepatocellular carcinoma (HCC) through the activity of intrahepatic macrophages. However, the tumor-promoting function of macrophages in the model has not been confirmed by either macrophage depletion or selective gene depletion in macrophages. Here we show that targeted mutation of Cd24 dramatically increased HCC burden while reducing intrahepatic macrophages and DEN-induced hepatocyte apoptosis. Depletion of macrophages also increased HCC burden and reduced hepatocyte apoptosis, thus establishing macrophages as an innate effector recognizing DEN-induced damaged hepatocytes. Mechanistically, Cd24 deficiency increased the levels of p53 in macrophages, resulting in their depletion in Cd24^-/- mice following DEN treatment. These data demonstrate that the Cd24-p53 axis maintains intrahepatic macrophages, which can remove hepatocytes with DNA damage. Our data establish a critical role for macrophages in suppressing HCC development and call for an appraisal of the current dogma that intrahepatic macrophages promote HCC development.

CD24 aggravates acute liver injury in autoimmune hepatitis by promoting IFN-γ production by CD4+ T cells

The T-cell-mediated immune response is implicated in many clinical hepatic injuries, such as autoimmune hepatitis and acute virus hepatitis. CD24 is widely expressed by different immune cells and plays an important role in the pathogenesis of many autoimmune diseases. However, the role of CD24 in T-cell-mediated liver injury has not been elucidated until now. Here we showed that CD24 deficiency protects mice from concanavalin A (ConA)-induced fulminant liver injury by reducing serum interferon-γ (IFN-γ) levels. CD24 expression by hepatic T cells was markedly increased following ConA challenge. Moreover, decreased IFN-γ production by hepatic CD4⁺ T cells in CD24-deficient mice was detected, which was correlated with downregulated phosphorylation of STAT1 in hepatic tissue. In vitro experiments also supported the conclusion that CD24 deficiency impaired IFN-γ production by CD4⁺ T cells following ConA, CD3/CD28 and phorbol myristate acetate/ionomycin stimulation. Our study suggests that CD24 deficiency confers hepatoprotection by decreasing CD4⁺ T-cell-dependent IFN-γ production in vivo, which suggests that CD24 might be a potential target molecule for reducing clinical hepatitis.

CD24 blunts oral squamous cancer development and dampens the functional expansion of myeloid-derived suppressor cells

CD24 expression has been implicated in the oncogenesis of multiple types of cancer and high tumor expression is considered a poor prognosis factor; however, the role of CD24 in oral cancer progression is unknown. Unlike other cancer types, we found that higher CD24 levels in human oral cancers are correlated to lower clinical stage and better overall survival. We then dissected the role of CD24 and mechanisms in oral cancer pathogenesis in mice using a genetic strategy and demonstrated that CD24 deficiency increased the oral cavity tumor burden in response to the carcinogen 4-nitroquioline 1-oxide (4-NQO). Immune profile analysis showed a significant expansion as well as increased suppressive function of myeloid-derived suppressor cells (MDSCs) in CD24^-/- mice, but no apparent impairment in T cells, B cells, or dendritic cells. Further, studies with an orthotopically transplanted syngeneic squamous carcinoma model in the tongue of CD24^-/- and CD24^+/- mice confirmed the protective roles of CD24 against cancer. Moreover, the difference in tumor growth between CD24^-/- and CD24^+/- mice was blunted by immunodepletion of MDSCs. We conclude that CD24 expression impedes MDSC expansion and function, and thus slows oral cancer oncogenesis. This study is the first to examine the role of CD24 in a de novo oral cancer model, and it highlights the need to consider the immune regulatory roles of CD24 in the development of CD24-targeted therapy for cancer.

Association between the CD24 Ala57Val polymorphism and risk for multiple sclerosis and systemic lupus erythematosus: a meta-analysis

The cluster of differentiation 24 (CD24) Ala57Val polymorphism has been implicated as a risk factor for multiple sclerosis (MS) and systemic lupus erythematosus (SLE); however, genetic studies have produced controversial results. A meta-analysis was performed on this topic. We used odds ratio (OR) and 95% confidence interval (95% CI) to investigate the strength of association. Eleven studies from nine publications consisting of 2466 cases and 2650 controls were included. The results suggested that the CD24 Val/Val genotypes were associated with an increased risk of MS in all study subjects and Caucasians (OR = 2.28, 95% CI: 1.68–3.10, P_z < 0.001 and OR = 2.30, 95% CI: 1.66–3.20, P_z < 0.001, respectively). Sensitivity analysis showed that no individual study was found to be significantly biasing the pooled results. Although meta-analysis also suggested an association between the CD24 Val/Val genotypes and SLE risk in Caucasians (OR = 1.71, 95% CI: 1.31–2.24, P_z < 0.001), sensitivity analysis demonstrated that the association was not statistically significant after removing a Spanish study. In conclusion, this meta-analysis suggests that the CD24 Ala57Val polymorphism is associated with an increased risk of MS in Caucasians. However, the available evidence is not sufficient to support an association between the CD24 Ala57Val polymorphism and SLE risk.

A critical role for the regulated wnt-myc pathway in naive T cell survival

Wnt signaling is involved in T cell development, activation, and differentiation. However, the role for Wnt signaling in mature naive T cells has not been investigated. In this article, we report that activation of Wnt signaling in T cell lineages by deletion of the Apc (adenomatous polyposis coli) gene causes spontaneous T cell activation and severe T cell lymphopenia. The lymphopenia is the result of rapid apoptosis of newly exported, mature T cells in the periphery and is not due to defects in thymocyte development or emigration. Using chimera mice consisting of both wild-type and Apc-deficient T cells, we found that loss of naive T cells is due to T cell intrinsic dysregulation of Wnt signaling. Because Apc deletion causes overexpression of the Wnt target gene cMyc, we generated mice with combined deletion of the cMyc gene. Because combined deletion of cMyc and Apc attenuated T cell loss, cMyc overexpression is partially responsible for spontaneous T cell apoptosis and lymphopenia. Cumulatively, our data reveal a missing link between Wnt signaling and survival of naive T cells.

Mesenchymal stem cell population derived from human pluripotent stem cells displays potent immunomodulatory and therapeutic properties

Mesenchymal stem cells (MSCs) are being tested in a wide range of human diseases; however, loss of potency and inconsistent quality severely limit their use. To overcome these issues, we have utilized a developmental precursor called the hemangioblast as an intermediate cell type in the derivation of a highly potent and replenishable population of MSCs from human embryonic stem cells (hESCs). This method circumvents the need for labor-intensive hand-picking, scraping, and sorting that other hESC-MSC derivation methods require. Moreover, unlike previous reports on hESC-MSCs, we have systematically evaluated their immunomodulatory properties and in vivo potency. As expected, they dynamically secrete a range of bioactive factors, display enzymatic activity, and suppress T-cell proliferation that is induced by either allogeneic cells or mitogenic stimuli. However, they also display unique immunophenotypic properties, as well as a smaller size and >30,000-fold proliferative capacity than bone marrow-derived MSCs. In addition, this is the first report which demonstrates that hESC-MSCs can inhibit CD83 up-regulation and IL-12p70 secretion from dendritic cells and enhance regulatory T-cell populations induced by interleukin 2 (IL-2). This is also the first report which shows that hESC-MSCs have therapeutic efficacy in two different autoimmune disorder models, including a marked increase in survival of lupus-prone mice and a reduction of symptoms in an autoimmune model of uveitis. Our data suggest that this novel and therapeutically active population of MSCs could overcome many of the obstacles that plague the use of MSCs in regenerative medicine and serve as a scalable alternative to current MSC sources.

Siglec-G-CD24 axis controls the severity of graft-versus-host disease in mice

Activation of sialic-acid-binding immunoglobulin-like lectin-G (Siglec-G) by noninfectious damage-associated molecular patterns controls innate immune responses. However, whether it also regulates T-cell-mediated adaptive immune responses is not known. Graft-versus-host reaction is a robust adaptive immune response caused by allogeneic hematopoietic cell transplantation that have been activated by antigen-presenting cells (APCs) in the context of damaged host tissues following allogeneic hematopoietic cell transplantation. The role of infectious and noninfectious pattern recognition receptor-mediated activation in the induction and aggravation of graft-versus-host disease (GVHD) is being increasingly appreciated. But the role of pathways that control innate immune responses to noninfectious stimuli in modulating GVHD has heretofore not been recognized. We report that Siglec-G expression on host APCs, specifically on hematopoietic cells, negatively regulates GVHD in multiple clinically relevant murine models. Mechanistic studies with various relevant Siglec-G and CD24 knockout mice and chimeric animals, along with rescue experiments with novel CD24 fusion protein demonstrate that enhancing the interaction between Siglec-G on host APCs with CD24 on donor T cells attenuates GVHD. Taken together, our data demonstrate that Siglec-G-CD24 axis, controls the severity of GVHD and suggest that enhancing this interaction may represent a novel strategy for mitigating GVHD.

CD24 gene polymorphism--a novel prognostic factor in esophageal cancer

BACKGROUND

The CD24 gene has been correlated with poor prognosis of various malignancies. The significance of CD24 in esophageal cancer remains unknown. Our aim was to evaluate the association between CD24 genetic polymorphism and esophageal cancer.

MATERIALS AND METHODS

Between June 2011 and May 2012 patients with esophageal cancer and healthy controls were prospectively enrolled and clinicopathological data were collected. Genomic DNA was extracted and restriction fragment length polymorphism (RFLP) analysis was performed to determine CD24 polymorphism at the coding region of CD24, which results in a substitution of the amino acid Ala by Val. Statistical significance was determined by unpaired t-test, χ²-test, and Fisher's exact test.

RESULTS

A total of 102 patients were included, of whom 51 had esophageal cancer and the rest comprised a healthy control group. The incidence of the polymorphism variant (Val/Val) among the healthy subjects and the esophageal cancer cohort was 6% in both groups. The incidence of N3 (metastasis in 7 or more regional lymph nodes) was markedly higher in those esophageal cancer patients who carried the polymorphism variant compared with those who did not carry it (66% and 2%, respectively, p=0.007). No significant difference was found between the groups with regard to age, gender, histology type, tumor location, tumor stage, and other histological characteristics of the tumor.

CONCLUSIONS

This CD24 polymorphism may serve as a novel prognostic marker identifying esophageal cancer patients with poor prognosis. Further studies are warranted to evaluate CD24 function and to validate its predictive potential with regard to esophageal cancer.

Peripheral CD24hi CD27+ CD19+ B cells subset as a potential biomarker in naïve systemic lupus erythematosus

AIM

B cells are likely to play critical roles in the pathogenesis of systemic lupus erythematosus (SLE). Our aim was to investigate the role of peripheral CD24(hi) CD27(+) CD19(+) B cells in Chinese patients with new-onset SLE.

METHOD

Peripheral CD24(hi) CD27(+) CD19(+) B cells were analyzed in 55 new-onset lupus and 36 healthy controls by flow cytometry. All SLE cases were treated with prednisolone and hydroxychloroquine during a 1-year follow-up. Thirteen cases were added with cyclophosphamide or mycophenolate mofetil. The CD24(hi) CD27(+) CD19(+) B cells were analyzed at days 0, 7, 14 and months 1, 3, 6, 9 and 12. Interleukin-10 (IL-10)-producing B cell was detected in eight naïve lupus and 10 healthy controls.

RESULTS

Compared to healthy controls, the frequency and number of primary circulating CD24(hi) CD27(+) CD19(+) B cells was significantly reduced in SLE cases (8.22 ± 3.48% vs. 31.67 ± 5.53%, P < 0.0001; 4.04 ± 2.85 vs. 38.66 ± 10.22 10(3) cells/mL, P = 0.0001) before treatment; IL-10(+) CD19(+) B cells and IL-10(+) CD24(hi) CD27(+) CD19(+) B cells also decreased in SLE. Interestingly, primary CD24(hi) CD27(+) CD19(+) B cells inversely correlated with SLE disease activity index (SLEDAI) score. Patients with arthritis and hematologic disorders had a lower primary CD24(hi) CD27(+) CD19(+) B cells. In 48 SLE cases who finished the 1-year follow-up, the frequency and number of CD24(hi) CD27(+) CD19(+) B cells increased from 8.26 ± 3.61% to 25.51 ± 4.56%; 3.99 ± 2.86 to 28.64 ± 11.81 10(3) cells/mm(3) (P < 0.0001), accompanied by a significantly decreased SLEDAI score. Of note, CD24(hi) CD27(+) CD19(+) B cells decreased in some flare cases with an elevated SLEDAI score.

CONCLUSION

These results demonstrate that a lower primary CD24(hi) CD27(+) CD19(+) B cells may be an immunologic aspect of new-onset SLE. CD24(hi) CD27(+) CD19(+) B cells may be a useful tool to evaluate lupus activity and monitor the response to therapy.

CD24 polymorphisms cannot predict pathologic complete response to anthracycline- and taxane-based neoadjuvant chemotherapy in breast cancer

INTRODUCTION

To evaluate the correlations between CD24 polymorphisms and clinicopathologic variables of patients with breast cancer.

PATIENTS AND METHODS

Single-nucleotide polymorphisms (SNPs) of CD24 were genotyped by the Sequenom MassArray iPLEX Gold System in 170 patients with breast cancer, and a total of 120 patients with histologically confirmed T2-4N0-2 M0 breast cancer were recruited to therapy with docetaxel, doxorubicin, and cyclophosphamide (TAC) as neoadjuvant chemotherapy. Data were analyzed by the chi-square test and logistic regression analysis.

RESULTS

There were no significant correlations between CD24 polymorphisms and any of the clinicopathologic variables, and no significant associations were found between either of the polymorphisms and CD24 protein expression. The clinical response rate and the pathologic complete response (pCR) rate were 68.8% and 27.1% in patients with the CD24 rs3838646 CA/CA genotype, and 87.5% and 20.8% in CD24 CA/Del and Del/Del genotype. There were no statistically significant differences between the CA/CA group and the Del allele group. The clinical response rate was 85.4% in patients with the CD24 rs52812045 C/C genotype and 63.9% in patients with the CD24 C/T and T/T genotype. There was a statistically significant difference between the C/C group and the T allele group (odds ratio = 0.28; 95% confidence interval, 0.11-0.73, P = .01). The pCR rate was 29.2% in patients with the CD24 rs52812045 C/C genotype and 23.6% in patients with the CD24 C/T and T/T genotype. There were no statistically significant differences between the C/C group and the T allele group. In a multivariate analysis, there was no correlation between CD24 rs3838646 or rs52812045 genotype and pCR.

CONCLUSION

CD24 rs3838646 and rs52812045 polymorphism could not predict the pathologic complete response to anthracycline- and taxane-based neoadjuvant chemotherapy in breast cancer. Additional larger studies are required to confirm this finding.

Differences and similarities in the transcriptional profile of peripheral whole blood in early and late-onset preeclampsia: insights into the molecular basis of the phenotype of preeclampsiaa

OBJECTIVE

Preeclampsia (PE) can be sub-divided into early- and late-onset phenotypes. The pathogenesis of these two phenotypes has not been elucidated. To gain insight into the mechanisms of disease, the transcriptional profiles of whole blood from women with early- and late-onset PE were examined.

METHODS

A cross-sectional study was conducted to include women with: i) early-onset PE (diagnosed prior to 34 weeks, n=25); ii) late-onset PE (after 34 weeks, n=47); and iii) uncomplicated pregnancy (n=61). Microarray analysis of mRNA expression in peripheral whole blood was undertaken using Affymetrix microarrays. Differential gene expression was evaluated using a moderated t-test (false discovery rate <0.1 and fold change >1.5), adjusting for maternal white blood cell count and gestational age. Validation by real-time qRT-PCR was performed in a larger sample size [early PE (n=31), late PE (n=72) and controls (n=99)] in all differentially expressed genes. Gene ontology analysis and pathway analysis were performed.

RESULTS

i) 43 and 28 genes were differentially expressed in early- and late-onset PE compared to the control group, respectively; ii) qRT-PCR confirmed the microarray results for early and late-onset PE in 77% (33/43) and 71% (20/28) of genes, respectively; iii) 20 genes that are involved in coagulation (SERPINI2), immune regulation (VSIG4, CD24), developmental process (H19) and inflammation (S100A10) were differentially expressed in early-onset PE alone. In contrast, only seven genes that encoded proteins involved in innate immunity (LTF, ELANE) and cell-to-cell recognition in the nervous system (CNTNAP3) were differentially expressed in late-onset PE alone. Thirteen genes that encode proteins involved in host defense (DEFA4, BPI, CTSG, LCN2), tight junctions in blood-brain barrier (EMP1) and liver regeneration (ECT2) were differentially expressed in both early- and late-onset PE.

CONCLUSION

Early- and late-onset PE are characterized by a common signature in the transcriptional profile of whole blood. A small set of genes were differentially regulated in early- and late-onset PE. Future studies of the biological function, expression timetable and protein expression of these genes may provide insight into the pathophysiology of PE.

CD24 polymorphisms in breast cancer: impact on prognosis and risk

Overexpression of CD24 has a negative impact on breast cancer prognosis. We have recently reported that the CD24 codon 57 Val/Val genotype (rs52812045) is associated with pathologic complete response after neoadjuvant chemotherapy for primary breast cancer and correlates with intratumoral lymphocyte infiltrates. This study was performed to investigate the influence of CD24 polymorphisms on breast cancer prognosis and risk. A total of 2,514 patients and 4,858 controls recruited as part of the MARIE study, a population-based case-control study, were genotyped for two CD24 polymorphisms (rs52812045, rs3838646) using TaqMan custom genotyping assays. Associations with overall and breast cancer-specific survival were assessed using uni- and multivariable Cox regression models stratified by age at diagnosis and adjusted for prognostic factors. Conditional logistic regression analysis adjusted for major risk factors was used to estimate multivariable odds ratios for risk of putative allele carriers compared to wildtype carriers. CD24 Ala/Val was significantly associated with breast cancer prognosis [Val/Val hazard ratio (HR)(adjusted) = 1.52; 95 % confidence interval (CI): 1.00-2.30, p = 0.05 and HR(adjusted) = 1.83; 95 % CI: 1.10-3.05, p = 0.018 for all-cause and breast cancer-specific mortality, respectively). The association was significant only in patients with a BMI <25 and in those who received adjuvant chemotherapy. None of the CD24 alleles was associated with breast cancer risk. These results provide further evidence of the CD24 Val/Val genotype influencing outcome in primary breast cancer. Together with previous data of CD24 overexpression as a poor prognostic marker, the findings underline the biological importance of CD24 for breast cancer.

CD24 on thymic APCs regulates negative selection of myelin antigen-specific T lymphocytes

Negative selection plays a key role in the clonal deletion of autoreactive T cells in the thymus. However, negative selection is incomplete; as high numbers of autoreactive T cells can be detected in normal individuals, mechanisms that regulate negative selection must exist. In this regard, we previously reported that CD24, a GPI-anchored glycoprotein, is required for thymic generation of autoreactive T lymphocytes. The CD24-deficient 2D2 TCR transgenic mice (2D2(+) CD24(-/-) ), whose TCR recognizes myelin oligodendrocyte glycoprotein (MOG), fail to generate functional 2D2 T cells. However, it was unclear if CD24 regulated negative selection, and if so, what cellular mechanisms were involved. Here, we show that elimination of MOG or Aire gene expression in 2D2(+) CD24(-/-) mice - through the creation of 2D2(+) CD24(-/-) MOG(-/-) or 2D2(+) CD24(/) ∼Aire(-/-) mice - completely restores thymic cellularity and function of 2D2 T cells. Restoration of CD24 expression on DCs, but not on thymocytes also partially restores 2D2 T-cell generation in 2D2(+) CD24(-/-) mice. Taken together, we propose that CD24 expression on thymic antigen-presenting cells (mTECs, DCs) down-regulates autoantigen-mediated clonal deletion of autoreactive thymocytes.

Lessons from common markers of tumor-initiating cells in solid cancers

Tumor-initiating cells (TICs) have emerged as the driving force of carcinomas, which appear as hierarchically structured. TICs as opposed to the tumor bulk display tumor forming potential, which is linked to a certain degree of self-renewal and differentiation, both major features of stem cells. Markers such as CD44, CD133, CD24, EpCAM, CD166, Lgr5, CD47, and ALDH have been described, which allow for the prospective enrichment of TICs. It is conspicuous that the same markers allow for an enrichment of TICs in various entities and, on the other hand, that different combinations of these markers were independently reported for the same tumor entity. Potential functions of these markers in the regulation of TIC phenotypes remained somewhat neglected although they might give insights in common molecular themes of TICs. The present review discusses major TIC markers with respect to their function and potential contributions to the tumorigenic phenotype of TICs.

CD24 Ala57Val polymorphism predicts pathologic complete response to sequential anthracycline- and taxane-based neoadjuvant chemotherapy for primary breast cancer

Overexpression of CD24 is an independent prognostic factor for breast cancer. Recently, two polymorphisms in the CD24 gene were linked to disease risk and progression in autoimmune diseases. Here, we evaluated the clinical relevance of these polymorphisms with respect to their potential to predict a pathologic complete response (pCR) to neoadjuvant chemotherapy (NCT) for primary breast cancer (PBC), one of the strongest prognostic factors in this setting. A total of 257 patients were randomized to either doxorubicin/cyclophosphamide (AC) or doxorubicin/pemetrexed (AP), both followed by docetaxel (Doc) as NCT for T2-4 N0-2 M0 PBC as part of an international, multicenter, randomized phase II trial. CD24 polymorphisms were analyzed on germ line DNA and correlated with clinicopathologic variables and pCR. No significant associations were found between either of the polymorphisms and any of the clinicopathologic variables. In a multivariate analysis, CD24 Val/Val genotype was the only significant predictor of pCR (OR: 4.97; P = 0.003). The predictive potential was significant in both treatment arms and in the hormone receptor-positive subgroup. There was no correlation between CD24 3'UTR (TG/Del) genotype and pCR. We did not observe any association between CD24 genotype and CD24 protein expression or in vitro chemosensitivity, but there was a significant correlation between CD24 Val/Val and intratumoral lymphocyte aggregates. In conclusion, CD24 Ala/Val SNP is a strong and independent predictor of pCR after NCT for PBC and may affect immune functions rather than tumor characteristics. Further evaluation of the CD24 function and validation of its predictive potential are clearly warranted.

Investigation of CD24 and its expression in Iranian relapsing-remitting multiple sclerosis

CD24 is a glycosylphosphatidylinositol (GPI)-linked cell surface glycoprotein expressed in central nervous system cells. Recent investigations have suggested that CD24 participates in the pathogenesis of experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS). However, a limited number of studies have been published regarding the contribution of CD24 to the risk and severity of MS in humans. We investigated the contribution of a CD24 single nucleotide polymorphism (SNP) to MS disease risk and severity. We also studied mRNA expression of the CD24 gene in Iranian MS patients using quantitative real-time polymerase chain reaction (PCR). Our findings showed that the CD24(v/v) genotype was significantly more frequent in MS patients compared with controls (p(c) = .004). Moreover, a statistically significant difference in the Multiple Sclerosis Severity Score (MSSS) was found between MS patients carrying CD24(a/a) and CD24(v/v) genotypes (p = .008). The results also indicated that the expression of CD24 mRNA was 1.7 times more in MS patients compared with controls. In conclusion, our results suggest that the CD24(v/v) genotype influences both MS disease risk and severity in Iranian MS patients, and the high disease severity in CD24(v/v) patients may indicate that they require more aggressive treatment than do patients carrying CD24(a/a).

Analysis of the influence of two CD24 genetic variants in Crohn's disease and ulcerative colitis

The aim of this study was to evaluate the possible implication of CD24 gene in the genetic predisposition to inflammatory bowel disease (IBD). Our study population consisted of 1321 female Spanish individuals (369 Crohn's disease [CD] patients, 323 ulcerative colitis [UC] patients, and 629 healthy matched controls). Two putative functional polymorphisms, a C to T coding polymorphism (rs8734) and a TG deletion in the 3' untranslated region (rs3838646), were used as CD24 genetic markers and genotyped using a Taqman 5' allelic discrimination assay. The "del" allele of the dinucleotide deletion was associated with an increased risk of CD (odds ratio = 1.61, 95% confidence interval = 1.17-2.21, p(FDR) = 6.4E-03) but not with UC. Moreover, this allele was significant associated with the age of CD diagnosis between 17 and 40 years, the ileocolonic location, and the inflammatory behavior of CD. We observed no significant differences between the allelic or genotypic frequencies of the A57V polymorphism in our studied IBD cohort. Our results suggest that the rs3838646 CD24 polymorphism is part of the genetic background of CD.

CD24 as a genetic modifier of disease progression in multiple sclerosis in Argentinean patients

INTRODUCTION

Previous reports have shown that CD24 gene polymorphisms have an important role in the risk of development and progression of multiple sclerosis (MS).

OBJECTIVE

To investigate the association between P226 polymorphisms (T/C), P1056 (A/G), P1527 (TG/del) and P1626 (A/G) of the CD24 gene and MS, comparing allele and genotype frequencies of patients versus controls.

MATERIALS AND METHODS

We analyzed DNA samples from 102 MS patients and from 205 unrelated healthy individuals. DNA was extracted from peripheral blood and polymorphic regions were amplified by nested PCR. Genotyping was performed by restriction fragments length polymorphisms. Time from disease onset to reach EDSS 6 and time to conversion to secondary progressive phase (SP) were used as variables of survival as well as percentage of patients that reached those endpoints. We used the log Rank test for data comparison (significant p≤0.05).

RESULTS

We found no differences between cases and controls in frequency of polymorphisms at the CD24 gene. 44.6% of patients with the AA genotype (P1626) reached an EDSS 6 vs 16% of patients with other genotypes (p<0.001, HR 3.2, 95% CI 1.4 to 7.4). 45.8% of patients with the AA genotype reached SPMS vs 16.7% without this genotype (p<0.001, HR 3.4, 95% CI 1.5 to 7.8).

CONCLUSIONS

This study showed a strong association between the presence of AA genotype in the 1626 polymorphism of the CD24 gene and the risk of disease progression in MS patients.

Dangers within: DAMP responses to damage and cell death in kidney disease

The response to exogenous pathogens leads to activation of innate immunity through the release of pathogen-associated molecular patterns (PAMPs) and their binding to pattern recognition receptors. A classic example is septic shock where Toll receptor 4 recognizes PAMPs. Although well accepted, this concept does not explain the activation of innate immunity and inflammation occurs with transplantation, autoimmunity, or trauma. Increasingly recognized is that endogenous molecules released by dying cells (damage-associated molecular patterns; DAMPs) activate cellular receptors leading to downstream inflammation. Thus endogenous danger signals and exogenous PAMPs elicit similar responses through seemingly similar mechanisms. Also emerging is our understanding that normal repair processes benefit from dampening the immune response to these endogenous danger molecules. Here we focus on the role of DAMPs and their putative receptors in the pathogenesis of acute and chronic kidney diseases.

NFAT5 regulates T lymphocyte homeostasis and CD24-dependent T cell expansion under pathologic hypernatremia

Immune cells rely on the transcription factor NFAT5 to adapt to hypertonic stress. The hypertonicity-dependent role of NFAT5 in T cells in vivo remains unclear because mouse models of NFAT5 deficiency have produced substantially different T cell phenotypes. In this study, we analyzed the T cell compartment in NFAT5-null and T cell-specific NFAT5 knockout mice. We found that NFAT5-null mice had constitutive, pronounced hypernatremia and suffered a severe immunodeficiency, with T cell lymphopenia, altered CD8 naive/memory homeostasis, and inability to reject allogeneic tumors. By contrast, T cell-specific NFAT5 knockout mice had normal plasma tonicity, rejected allogeneic tumors, and exhibited only a mild, low-penetrance memory bias in CD8 cells. Notably, when T cells from these mice were cultured ex vivo in hypernatremic media, they exhibited features found in NFAT5-null mice, with pronounced naive/memory imbalance and impaired homeostatic survival in response to IL-7, as well as a severe inhibition of their mitogen-induced proliferation. By analyzing surface receptors whose expression might be affected in NFAT5-deficient cells, we identified CD24 as a novel NFAT5 target induced by hypertonicity both in vitro and in vivo, and required to sustain T cell expansion under osmostress. NFAT5 bound to the Cd24 promoter in response to hypertonicity facilitated the local derepression of chromatin and enhanced the expression of CD24 mRNA and protein. Altogether, our results indicate that the systemic hypernatremia of NFAT5-null mice is a major contributor to their immunodeficiency, and highlight the role of NFAT5 and CD24 in the homeostasis of T cells under osmostress in vivo.

The persistence of T cell memory

T cell memory is a crucial feature of the adaptive immune system in the defense against pathogens. During the last years, numerous studies have focused their efforts on uncovering the signals, inflammatory cues, and extracellular factors that support memory differentiation. This research is beginning to decipher the complex gene network that controls memory programming. However, how the different signals, that a T cell receives during the process of differentiation, interplay to trigger memory programming is still poorly defined. In this review, we focus on the most recent advances in the field and discuss how T cell receptor signaling and inflammation control CD8 memory differentiation.

CD24 Ala57Val gene polymorphism and the risk of systemic lupus erythematosus

It was recently shown that the CD24 Ala57Val (rs 52812045) polymorphism plays a significant role in susceptibility to systemic lupus erythematosus (SLE) in a Spanish population, which has not been confirmed in other ethnic groups. We investigated the distribution of the CD24 Ala57Val polymorphism in patients with SLE (n = 250) and controls (n = 350) in Poland. The odds ratio (OR) for patients with SLE with the Ala/Val genotype compared with Ala/Ala genotype was 1.490 [95% confidence interval (CI) = 1.052-2.111, P = 0.0275], and OR for the Val/Val genotype compared with Ala/Ala genotypes was 2.001 (95% CI = 1.154-3.467, P = 0.0154). Moreover, we observed a significant association between the CD24 Val allele and the presence of anti-Scl-70 antibody (Ab) OR = 2.155 (1.438-3.229, P = 0.0002). There was also an association of Val allele with the presence of anti-snRNP Ab OR = 1.984 (1.266-3.110, P = 0.0034) in patients with SLE. We also found that the CD24 Val/Val and Ala/Val genotypes contribute to immunologic manifestations OR = 2.244 (1.323-3.806, P = 0.0037). Our observations indicate that the CD24 Ala57Val polymorphism may predispose to SLE incidence and can be linked to immunologic manifestations and production of autoantibodies in this disease.

CD24 gene polymorphism is associated with the disease progression and susceptibility to multiple sclerosis in the Iranian population

The impact of a single nucleotide polymorphism (SNP) in the CD24 gene on the risk and progression of multiple sclerosis (MS) was investigated in the Iranian population. Our data revealed that the susceptibility and the progression of MS in individuals with the CD24V/V genotype were greater than in those with the CD24A/V and CD24A/A genotypes.

Mechanisms of FUS1/TUSC2 deficiency in mesothelioma and its tumorigenic transcriptional effects

Background

FUS1/TUSC2 is a novel tumor suppressor located in the critical 3p21.3 chromosomal region frequently deleted in multiple cancers. We previously showed that Tusc2-deficient mice display a complex immuno-inflammatory phenotype with a predisposition to cancer. The goal of this study was to analyze possible involvement of TUSC2 in malignant pleural mesothelioma (MPM) - an aggressive inflammatory cancer associated with exposure to asbestos.

Methods

TUSC2 insufficiency in clinical specimens of MPM was assessed via RT-PCR (mRNA level), Representational Oligonucleotide Microarray Analysis (DNA level), and immunohistochemical evaluation (protein level). A possible link between TUSC2 expression and exposure to asbestos was studied using asbestos-treated mesothelial cells and ROS (reactive oxygen species) scavengers. Transcripional effects of TUSC2 in MPM were assessed through expression array analysis of TUSC2-transfected MPM cells.

Results

Expression of TUSC2 was downregulated in ~84% of MM specimens while loss of TUSC2-containing 3p21.3 region observed in ~36% of MPMs including stage 1 tumors. Exposure to asbestos led to a transcriptional suppression of TUSC2, which we found to be ROS-dependent. Expression array studies showed that TUSC2 activates transcription of multiple genes with tumor suppressor properties and down-regulates pro-tumorigenic genes, thus supporting its role as a tumor suppressor. In agreement with our knockout model, TUSC2 up-regulated IL-15 and also modulated more than 40 other genes (~20% of total TUSC2-affected genes) associated with immune system. Among these genes, we identified CD24 and CD274, key immunoreceptors that regulate immunogenic T and B cells and play important roles in systemic autoimmune diseases. Finally, clinical significance of TUSC2 transcriptional effects was validated on the expression array data produced previously on clinical specimens of MPM. In this analysis, 42 TUSC2 targets proved to be concordantly modulated in MM serving as disease discriminators.

Conclusion

Our data support immuno-therapeutic potential of TUSC2, define its targets, and underscore its importance as a transcriptional stimulator of anti-tumorigenic pathways.

CD24-Siglec G/10 discriminates danger- from pathogen-associated molecular patterns

It is now well accepted that the innate immune system recognizes both damage (or danger)- and pathogen-associated molecular patterns (DAMP and PAMP, respectively) through pattern recognition receptors, such as Toll-like receptors (TLR) and/or Nod-like receptors (NLR). Less clear are whether and how the response to PAMP and DAMP are regulated differentially. The answers may reveal whether the primary goal of the immune system is to defend against infections or to alert the host of tissue injuries. We demonstrated recently that the host response to DAMP is controlled by a DAMP-CD24-Siglec axis. Here we propose a key role for the CD24-Siglec pathway in discriminating between DAMPs and PAMPs.