CD24-Siglec interactions in inflammatory diseases

From mechanism to therapy: the journey of CD24 in cancer

CD24 is a glycosylphosphatidylinositol-anchored protein that is expressed in a wide range of tissues and cell types. It is involved in a variety of physiological and pathological processes, including cell adhesion, migration, differentiation, and apoptosis. Additionally, CD24 has been studied extensively in the context of cancer, where it has been found to play a role in tumor growth, invasion, and metastasis. In recent years, there has been growing interest in CD24 as a potential therapeutic target for cancer treatment. This review summarizes the current knowledge of CD24, including its structure, function, and its role in cancer. Finally, we provide insights into potential clinical application of CD24 and discuss possible approaches for the development of targeted cancer therapies.

A new frontier in precision medicine: Exploring the role of extracellular vesicles in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory airway disease characterized by progressive respiratory difficulties. It has a high incidence and disability rate worldwide. However, currently there is still a lack of highly effective treatment methods for COPD, only symptom relief is possible. Therefore, there is an urgent need to explore new treatment options. Almost all cells can secrete extracellular vesicles (EVs), which participate in many physiological activities by transporting cargoes and are associated with the pathogenesis of various diseases. Recently, many scholars have extensively studied the relationship between COPD and EVs, which has strongly demonstrated the significant impact of EVs from different sources on the occurrence and development of COPD. Therefore, EVs are a good starting point and new opportunity for the diagnosis and treatment of COPD. In this review, we mainly describe the current mechanisms of EVs in the pathogenesis of COPD, also the relationship between diagnosis, prognosis, and treatment. At the same time, we also introduce some new methods for COPD therapy based on EVs. It is hoped that this article can provide new ideas for future research and contribute to the development of precision medicine.

Integrated genetic analysis of diabetic complications: Bioinformatics insights into foot ulcers, neuropathy and peripheral artery disease

Diabetic foot ulcers (DFU), diabetic peripheral neuropathy (DPN) and peripheral arterial disease (PAD) are common complications of diabetes mellitus, while diabetic peripheral neuropathy and peripheral arterial disease contribute to the pathogenesis of diabetic foot ulcers, and the pathogenic mechanisms between these three diseases still need further investigation. The keywords 'diabetic foot ulcer', 'diabetic peripheral neuropathy' and 'atherosclerosis' were used to search for related gene sets in the GEO database. Differentially expressed genes (DEGs) were screened and analysed for GO, KEGG and enrichR functional enrichment. Potential three disease biomarkers were identified by SVM-SVM-RFE and LASSO regression analysis. The results were also validated using external datasets and discriminability was measured by area under the ROC curve (AUC). Finally, biomarkers and co-upregulated genes were analysed through the GSEA and Attie Laboratories diabetes databases. A total of 11 shared genes (KRT16, CD24, SAMD9L, SRGAP2, FGL2, GPR34, DDIT4, NFE2L3, FBLN5, ANXA3 and CPA3), two biomarkers (SAMD9L and FGL2) and one co-upregulated gene (CD24) were screened. GO and KEGG pathway analysis of DEGs, enrichr enrichment analysis of shared differential genes and GSEA analysis of biomarkers showed that these significant genes were mainly focused on vasoregulatory, inflammatory-oxidative stress and immunomodulatory pathways. In this study, we used bioinformatics to investigate the intrinsic relationship and potential mechanisms of three common lower extremity complications of diabetes and identified two pivotal genes using the LASSO model and the SVM-RFE algorithm, which will further help clinicians to understand the relationship between diabetic complications, improve the diagnosis and treatment of diabetic foot problems and help doctors to identify the potential risk factors of diabetic foot.

Surprising magic of CD24 beyond cancer

CD24 has emerged as a molecule of significant interest beyond the oncological arena. Recent studies have unveiled its surprising and diverse roles in various biological processes and diseases. This review encapsulates the expanding spectrum of CD24 functions, delving into its involvement in immune regulation, cancer immune microenvironment, and its potential as a therapeutic target in autoimmune diseases and beyond. The 'magic' of CD24, once solely attributed to cancer, now inspires a new paradigm in understanding its multifunctionality in human health and disease, offering exciting prospects for medical advancements.

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.

Monocytes reprogrammed by 4-PBA potently contribute to the resolution of inflammation and atherosclerosis

Background

Chronic inflammation initiated by inflammatory monocytes underlies the pathogenesis of atherosclerosis. However, approaches that can effectively resolve chronic low-grade inflammation targeting monocytes are not readily available. The small chemical compound 4-phenylbutyric acid (4-PBA) exhibits broad anti-inflammatory effects in reducing atherosclerosis. Selective delivery of 4-PBA reprogrammed monocytes may hold novel potential in providing targeted and precision therapeutics for the treatment of atherosclerosis.

Methods

Systems analyses integrating single-cell RNA-sequencing and complementary immunological approaches characterized key resolving characteristics as well as defining markers of reprogrammed monocytes trained by 4-PBA. Molecular mechanisms responsible for monocyte reprogramming was assessed by integrated biochemical and genetic approaches. The inter-cellular propagation of homeostasis resolution was evaluated by co-culture assays with donor monocytes trained by 4-PBA and recipient naïve monocytes. The in vivo effects of monocyte resolution and atherosclerosis prevention by 4-PBA were assessed with the high fat diet-fed ApoE -/- mouse model with i.p. 4-PBA administration. Furthermore, the selective efficacy of 4-PBA trained monocytes were examined by i.v. transfusion of ex vivo trained monocytes by 4-PBA into recipient high fat diet-fed ApoE -/- mice.

Results

In this study, we found that monocytes can be potently reprogrammed by 4-PBA into an immune-resolving state characterized by reduced adhesion and enhanced expression of anti-inflammatory mediator CD24. Mechanistically, 4-PBA reduced the expression of ICAM-1 via reducing peroxisome stress and attenuating SYK-mTOR signaling. Concurrently, 4-PBA enhanced the expression of resolving mediator CD24 through promoting PPARγ neddylation mediated by TOLLIP. 4-PBA trained monocytes can effectively propagate anti-inflammation activity to neighboring monocytes through CD24. Our data further demonstrated that 4-PBA trained monocytes effectively reduce atherosclerosis pathogenesis when administered in vivo .

Conclusion

Our study describes a robust and effective approach to generate resolving monocytes, characterizes novel mechanisms for targeted monocyte reprogramming, and offers a precision-therapeutics for atherosclerosis based on delivering reprogrammed resolving monocytes.

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.