CD64: An Attractive Immunotherapeutic Target for M1-type Macrophage Mediated Chronic Inflammatory Diseases

Anti-CD64(scFv)-SNAP-Auristatin F: An in vitro proof of concept study for a recombinant antibody conjugate targeting CD64+ acute monocytic leukemia

Acute monocytic leukemia (AML-M5) is a rapidly progressing hematological malignancy characterized by limited therapeutic options and poor survival outcomes. Conventional therapies, such as intensive chemotherapy offer limited efficacy due to their lack of tumor specificity, significant systemic toxicities, and high risk of disease relapse after initial treatment, underscoring the need for more targeted therapeutic approaches. CD64 (FcγRI) is highly expressed on monocyte-derived myeloid leukemia cells and has been identified as a promising therapeutic target for the treatment of AML-M5. We have previously demonstrated that recombinant immunotoxins and their humanized counterparts (human cytolytic fusion proteins) can selectively target and eliminate CD64+ AML-M5 cells. However, their clinical efficacy is might be limited by immunogenicity and endosomal degradation. In this study, we developed a next-generation antibody-drug conjugate (ADC) consisting of an anti-CD64 single-chain variable fragment (H22(scFv)) conjugated to the anti-mitotic agent auristatin F in a 1:1 stoichiometry via a site-selective chemistry. This novel ADC demonstrated selective cytotoxicity against CD64+ monocytic leukemia cells in vitro, providing first compelling preclinical evidence for further clinical exploration of CD64-targeted therapies in treating aberrant myeloid leukemias.

New mesenchymal stem/stromal cell-based strategies for osteoarthritis treatment: targeting macrophage-mediated inflammation to restore joint homeostasis

Macrophages are pivotal in osteoarthritis (OA) pathogenesis, as their dysregulated polarization can contribute to chronic inflammatory processes. This review explores the molecular and metabolic mechanisms that influence macrophage polarization and identifies potential strategies for OA treatment. Currently, non-surgical treatments for OA focus only on symptom management, and their efficacy is limited; thus, mesenchymal stem/stromal cells (MSCs) have gained attention for their anti-inflammatory and immunomodulatory capabilities. Emerging evidence suggests that small extracellular vesicles (sEVs) derived from MSCs can modulate macrophage function, thus offering potential therapeutic benefits in OA. Additionally, the transfer of mitochondria from MSCs to macrophages has shown promise in enhancing mitochondrial functionality and steering macrophages toward an anti-inflammatory M2-like phenotype. While further research is needed to confirm these findings, MSC-based strategies, including the use of sEVs and mitochondrial transfer, hold great promise for the treatment of OA and other chronic inflammatory diseases.

Spatial visualization provides insight into immune modulation by an L-DBF vaccine formulation against Shigella

Shigellosis remains a global public health problem, especially in regions with poor sanitation measures. Our prior work has demonstrated the protective efficacy of a three-dose regimen of L-DBF, a recombinant fusion of IpaD and IpaB from Shigella flexneri with the LTA1 moiety of enterotoxigenic E. coli labile toxin. Here, we investigate how a two-dose regimen (one prime and one booster) of L-DBF, formulated in an oil-in-water emulsion called ME, modulates immune responses in the lung using a spatial transcriptomics approach. Our findings show significant changes in the lung immune landscape following the vaccination, including increased expression of B cell markers, antigen presentation genes, and T cell-associated markers. Our analysis also revealed significant reprogramming of fibroblasts and cardiomyocytes, showing that fibroblasts are shifted from extracellular matrix production to immune modulation, while cardiomyocytes enhanced the signaling for immune cell recruitment and vascular stability. The communication between alveolar type 2 (AT2) cells and cardiomyocytes also increased, reflecting coordinated support for immune readiness and maintaining tissue integrity. These findings underscore the potential of L-DBF/ME vaccination to enhance both humoral and cellular immunity, as well as to reshape lung immune architecture while enhancing immune readiness, thereby offering a promising approach for effective protection against Shigella infections.

Somatic Miwi2 modulates mitochondrial function in airway multiciliated cells and exacerbates influenza pathogenesis

MIWI2, a P element-induced wimpy testes (PIWI) argonaute protein known for suppressing retrotransposons during male gonadogenesis, has an unexplored role in mammalian somatic cells. We identify MIWI2 multiciliated (M2MC) cells as a rare subset of airway multiciliated cells and investigate MIWI2's function in antiviral host defense. We analyzed transcriptomes from Miwi2 heterozygous (Miwi2 +/tom) and deficient (Miwi2 tom/tom) mice following influenza A infection. During infection, Miwi2 deficiency was associated with reduced mitochondrial and ribosomal gene expression in M2MC cells, increased mitochondrial reactive oxygen species (ROS) production and ADP/ATP ratios in multiciliated cells, and enhanced viral clearance and recovery. Additionally, Miwi2-expressing cells exhibited reduced levels of small RNAs derived from nuclear mitochondrial DNA. These findings reveal a previously unrecognized role for Miwi2 in regulating small non-coding RNAs and mitochondrial oxidant production in somatic cells, indicating a function beyond its established germline activities. Our study identifies Miwi2/Piwil4 as a potential factor influencing susceptibility to severe respiratory infections.

Identification of aging-related biomarkers for intervertebral disc degeneration in whole blood samples based on bioinformatics and machine learning

Introduction

Aging is characterized by gradual structural and functional changes in the body over time, with intervertebral disc degeneration (IVDD) representing a key manifestation of spinal aging and a major contributor to low back pain (LBP).

Methods

This study utilized bioinformatics and machine learning approaches to identify aging-related biomarkers associated with IVDD in whole blood samples. By analyzing GEO datasets alongside aging-related databases such as GeneCards, HAGR, and AgeAnno, we identified 15 aging-related differentially expressed genes (AIDEGs). Correlation and immune infiltration analyses were conducted on these AIDEGs, and diagnostic models were developed using WGCNA, logistic regression, random forest, support vector machine, k-nearest neighbors, and LASSO regression to identify key genes.

Results

Among these, FCGR1A, CBS, and FASLG emerged as significant biomarkers with strong predictive capabilities for IVDD. Further exploration of biological pathways involving AIDEGs provided insights into their potential roles in IVDD pathogenesis. To further validate these findings, we collected human blood specimens and conducted in vitro experiments. ELISA assays confirmed that CBS and FASLG are crucial biomarkers of IVDD, with distinct expression patterns in patients with moderate versus severe degeneration.

Discussion

These results highlight the diagnostic potential of AIDEGs and provide a new perspective for early intervention and treatment strategies in IVDD.

Relationships among immune cells, metabolites, and non-small cell lung cancer: a mediation Mendelian randomization study

BACKGROUND

Immune cells and metabolites significantly impact organism health and disease processes. The interaction between non-small cell lung cancer (NSCLC) and metabolites and immune cells remains underexplored.

METHODS

To investigate the causal relationships between immune cells, metabolites, and NSCLC, we used Mendelian randomization (MR). The research design comprehensively embraced the direct correlation and the role that metabolites play as an intermediate in the interaction between NSCLC and immune cells.

RESULTS

MR analysis allowed us to finally identify one immune cell, there was a substantial causal connection between CD64 on CD14⁻CD16⁻ and NSCLC. Furthermore, we discovered four metabolites that showed strong causal links to NSCLC: 1-(1-enyl-stearoyl)-2-arachidonoyl-GPE (p-18:0/20:4) levels, phenyllactate (PLA) levels in elite athletes, the caffeine to paraxanthine ratio and 1-palmitoyl-2-arachidonoyl-GPC (16:0/20:4n6) levels. Finally, through a two-step MR mediation analysis, we found that CD64 on CD14⁻CD16⁻ mediated the occurrence of NSCLC via 1-palmitoleoyl-2-linolenoyl-GPC (16:1/18:3) levels and the caffeine to paraxanthine ratio, with mediation proportions of - 11.89% and 21.69%, respectively.

CONCLUSION

Our findings show the complicated link between immune cells, metabolites, and NSCLC. The discovered connections and mediating effects provide important insights.

Anti-IL-17 Inhibits PINK1/Parkin Autophagy and M1 Macrophage Polarization in Rheumatic Heart Disease

Rheumatic heart disease (RHD) is an important and preventable cause of cardiovascular death and disability, but the lack of clarity about its exact mechanisms makes it more difficult to find alternative methods or prevention and treatment. We previously demonstrated that increased IL-17 expression plays a crucial role in the development of RHD-related valvular inflammatory injury. Macrophage autophagy/polarization may be a pro-survival strategy in the initiation and resolution of the inflammatory process. This study investigated the mechanism by which IL-17 regulates autophagy/polarization activation in macrophages. A RHD rat model was generated, and the effects of anti-IL-17 and 3-methyladenine (3-MA) were analyzed. The molecular mechanisms underlying IL-17-induced macrophage autophagy/polarization were investigated via in vitro experiments. In our established RHD rat model, the activation of the macrophage PINK1/Parkin autophagic pathway in valve tissue was accompanied by M1 macrophage infiltration, and anti-IL-17 treatment inhibited autophagy and reversed macrophage inflammatory infiltration, thereby attenuating endothelial-mesenchymal transition (EndMT) in the valve tissue. The efficacy of 3-MA treatment was similar to that of anti-IL-17 treatment. Furthermore, in THP-1 cells, the pharmacological promotion of autophagy by IL-17 induced M1-type polarization, whereas the inhibition of autophagy by 3-MA reversed this process. Mechanistically, silencing PINK1 in THP-1 blocked autophagic flux. Moreover, IL-17-induced M1-polarized macrophages promoted EndMT in HUVECs. This study revealed that IL-17 plays an important role in EndMT in RHD via the PINK1/Parkin autophagic pathway and macrophage polarization, providing a potential therapeutic target.

Targeting prostate cancer by new bispecific monocyte engager directed to prostate-specific membrane antigen

Prostate cancer (PCa) ranks as the second leading cause of cancer-related deaths among men in the United States. Prostate-specific membrane antigen (PSMA) represents a well-established biomarker of PCa, and its levels correlate positively with the disease progression, culminating at the stage of metastatic castration-resistant prostate cancer. Due to its tissue-specific expression and cell surface localization, PSMA shows superior potential for precise imaging and therapy of PCa. Antibody-based immunotherapy targeting PSMA offers the promise of selectively engaging the host immune system with minimal off-target effects. Here we report on the design, expression, purification, and characterization of a bispecific engager, termed 5D3-CP33, that efficiently recruits macrophages to the vicinity of PSMA-positive cancer cells mediating PCa death. The engager was engineered by fusing the anti-PSMA 5D3 antibody fragment to a cyclic peptide 33 (CP33), selectively binding the Fc gamma receptor I (FcγRI/CD64) on the surface of phagocytes. Functional parts of the 5D3-CP33 engager revealed a nanomolar affinity for PSMA and FcγRI/CD64 with dissociation constants of KD =  3 nM and KD =  140 nM, respectively. At a concentration as low as 0.3 nM, the engager was found to trigger the production of reactive oxygen species by U937 monocytic cells in the presence of PSMA-positive cells. Moreover, flow cytometry analysis demonstrated antibody-dependent cell-mediated phagocytosis of PSMA-positive cancer cells by U937 monocytes when exposed to 0.15 nM 5D3-CP33. Our findings illustrate that 5D3-CP33 effectively and specifically activates monocytes upon PSMA-positive target engagement, resulting in the elimination of tumor cells. The 5D3-CP33 engager can thus serve as a promising lead for developing new immunotherapy tools for the efficient treatment of PCa.

Immune Cell-NSPC interactions: Friend or foe in CNS injury and repair?

Neural stem/progenitor cells (NSPCs) play a crucial role in central nervous system (CNS) development, regeneration, and repair. However, their functionality and therapeutic potential are intricately modulated by interactions with immune cells, particularly macrophages and microglia. Microglia, as CNS-resident macrophages, are distinct from peripheral macrophages in their roles and characteristics, contributing to specialized functions within the CNS. Recent evidence suggests that microglia, as CNS-resident macrophages, contribute to the quality assurance of NSPCs by eliminating stressed or dysfunctional cells, yet the mechanisms underlying this process remain largely unexplored. Furthermore, macrophage polarization states, such as M1 and M2, appear to differentially influence NSPC quality, potentially impacting neurogenesis and regenerative outcomes. Identifying surface markers indicative of NSPC stress could provide a strategy for selecting optimal cells for transplantation therapies. Additionally, in vivo clonal labeling approaches may enable precise tracking of NSPC fate and their interactions with immune cells. Beyond macrophages and microglia, the roles of other immune cells, including T cells and neutrophils, particularly in injury and neurodegenerative disease contexts, in the context of CNS injury and disease are emerging areas of interest. Here, I discuss the emerging evidence supporting the interplay between the immune system and NSPCs, highlighting critical gaps in knowledge and proposing future research directions to harness immune-mediated mechanisms for optimizing neural regeneration and transplantation strategies.

Uncovering Sex-Related Differences in Skin Macrophage Polarization During Wound Healing in Diabetic Mice

BACKGROUND

Chronic wounds, such as diabetes-related foot ulcers, arise from delayed wound healing and create significant health and economic burdens. Macrophages regulate healing by shifting between pro- and anti-inflammatory phenotypes, known as macrophage polarization. Sex and diabetes can impair wound healing, but their influence on macrophage phenotype in skin tissue during wound healing remains unclear, which was investigated in this study using a novel two-sex diabetic mouse model.

METHODS

Diabetes was induced in male and female C57BL/6J mice using low-dose streptozotocin injections and high-fat diet feeding, with chow-fed mice as controls. After 18 weeks, each mouse received four circular full-thickness dorsal skin wounds. The macrophage phenotypes in wounded skin tissues at Day 0 and Day 10 post-wounding were analyzed using mass cytometry with manual gating and automated computational clustering.

RESULTS

Male diabetic mice exhibited more severe hyperglycemia and insulin resistance compared to females. Although diabetic mice did not display delayed wound healing, male mice had a greater proportion of total macrophages than females, especially a higher proportion of pro-inflammatory matrix metalloproteinase-9 (MMP-9)+ macrophages and a lower proportion of anti-inflammatory adiponectin receptor 1 (AdipoR1)+ macrophages in male diabetic mice compared to females, indicating an imbalanced polarization towards a pro-inflammatory phenotype that could result in poorer wound healing. Interestingly, computational clustering identified a new pro-inflammatory, pro-healing phenotype (Ly6C+AdipoR1+CD163-CD206-) more abundant in females than males, suggesting this phenotype may play a role in the transition from the inflammatory to the proliferative stage of wound healing.

CONCLUSIONS

This study demonstrated a significant sex-based difference in macrophage populations, with male diabetic mice showing a pro-inflammatory bias that may impair wound healing, while a unique pro-inflammatory, pro-healing macrophage population more abundant in females could facilitate recovery. Further research is needed to investigate the role of these newly identified phenotypes in regulating impaired wound healing.

Inhibition of peptidyl arginine deiminase-4 ameliorated pulmonary fibrosis via modulating M1/M2 polarisation of macrophages

Pulmonary fibrosis (PF) arises from dysregulated wound healing, leading to excessive extracellular matrix (ECM) deposition and impaired lung function. Macrophages exhibit high plasticity, polarizing to pro-inflammatory M1 during early inflammation and anti-inflammatory, fibrosis-inducing M2 during later stages of PF. Additionally, neutrophils and neutrophil extracellular traps (NETs) release mediated by peptidyl arginine deiminase (PAD-4), also play a key role in PF progression. PAD-4 inhibitor chloro-amidine (CLA) has shown anti-fibrotic effects in bleomycin (BLM) induced PF mouse model in our earlier study. Here, we have demonstrated that CLA also exhibited inhibition of macrophage polarisation in in-vitro in THP-1 monocytes and in-vivo in BLM induced PF. THP-1 monocytes were exposed to NETs isolated from phorbol 12-myristate-13-acetate (PMA) stimulated and PMA plus CLA treated differentiated HL-60 (dHL-60) cells. Monocytes exposed to stimulated NETs resulted in increased oxidative stress, disrupted mitochondrial membrane potential and increased M1 and M2 macrophage markers. These alterations were abrogated in THP-1 cells upon exposure to CLA treated NETs. Further, CLA treatment in BLM induced mice improved abnormal BALF, biochemical, and histological parameters in line with our previous findings. Additionally, CLA also reduced M1 and M2 markers time-dependently, as shown by immunofluorescence (IF), western blot, and RT-PCR analysis. CLA treatment led to decreased expression of PAD-4, M1-related pro-inflammatory cytokines and M2-related pro-fibrotic cytokines and mediators, as confirmed by western blot and ELISA analysis. Thus, it is established that inhibition of PAD-4 lead to mitigation of macrophage polarisation and a combined anti-fibrotic effect is achieved which can be explored further.

Polarized macrophage functions are affected differentially after CSF-1R inhibition with PLX5622

PLX5622 is a colony stimulating factor 1 receptor (CSF-1R) inhibitor that is known to deplete microglial cells in vivo. Recently its effects on macrophages (Mφ) were also observed in vivo. Therefore, we performed this study to assess its in vitro effects on the differentiation and functions of polarized Mφ derived from different tissues. Our findings show that addition of PLX5622 early on after ex vivo isolation hinders Mφ differentiation and survival. However, its addition post Mφ differentiation did not significantly affect the viability. Furthermore, PLX5622 affects certain functions and degree of polarization of IL-4 (M2a) Mφ but not polarization of M1-like Mφ. Our study provides novel aspects on the application of PLX5622 to study Mφ functions in vitro, where polarization is affected by CSF-1R signalling and provides distinctive evidence to its ability to affect certain populations of Mφ during in vitro differentiation and maturation.

Flow Cytometry Analyses of Meningioma Immune Cell Composition Using a Short, Optimized Digestion Protocol

BACKGROUND

Current challenges in meningioma treatment, including post-surgical complications and cognitive impairments, highlight the need for new treatment alternatives. Immunological interventions have shown promise. However, there is a knowledge gap in characterizing infiltrating immune cells in meningioma and their interplay. Further studies on immune cells in single-cell suspensions from digested meningioma tissues could identify targetable mechanisms for non-surgical treatment options with fewer side effects. This study aimed to optimize a protocol for faster digestion of meningioma tissues into viable single-cell suspensions and to identify infiltrating immune cell populations.

METHODS

We modified a commercial kit intended for whole skin dissociation to digest resected meningioma tissues into viable single-cell suspensions. Tumor-infiltrating immune cell populations were characterized using flow cytometry.

RESULTS

Flow cytometry analyses revealed that the digested tissue was composed of viable immune cells, including predominantly CD14+ macrophages and CD3+ T cells, with minor populations of CD56+ NK cells and CD19+ B cells. In both of the two patient samples tested, half of the tumor-associated macrophages were TIM-3+, with a small proportion co-expressing CD83. Women were more likely to have a lower proportion of immune cells, B cells, and NK cells. Female patients with a high proportion of immune cells had a higher proportion of macrophages.

CONCLUSION

We successfully optimized a protocol for generating single-cell suspensions with viable immune cells from meningioma tissues, revealing infiltrating antigen-presenting cells with an immunosuppressive phenotype, and lymphocytes. This short protocol allows advanced analyses of tumor-infiltrating cells using techniques such as single-cell RNA sequencing and flow cytometry, which require live, dissociated cells.

Unraveling Macrophage Polarization: Functions, Mechanisms, and "Double-Edged Sword" Roles in Host Antiviral Immune Responses

Numerous viruses that propagate through the respiratory tract may be initially engulfed by macrophages (Mφs) within the alveoli, where they complete their first replication cycle and subsequently infect the adjacent epithelial cells. This process can lead to significant pathological damage to tissues and organs, leading to various diseases. As essential components in host antiviral immune systems, Mφs can be polarized into pro-inflammatory M1 Mφs or anti-inflammatory M2 Mφs, a process involving multiple signaling pathways and molecular mechanisms that yield diverse phenotypic and functional features in response to various stimuli. In general, when infected by a virus, M1 macrophages secrete pro-inflammatory cytokines to play an antiviral role, while M2 macrophages play an anti-inflammatory role to promote the replication of the virus. However, recent studies have shown that some viruses may exhibit the opposite trend. Viruses have evolved various strategies to disrupt Mφ polarization for efficient replication and transmission. Notably, various factors, such as mechanical softness, the altered pH value of the endolysosomal system, and the homeostasis between M1/M2 Mφs populations, contribute to crucial events in the viral replication cycle. Here, we summarize the regulation of Mφ polarization, virus-induced alterations in Mφ polarization, and the antiviral mechanisms associated with these changes. Collectively, this review provides insights into recent advances regarding Mφ polarization in host antiviral immune responses, which will contribute to the development of precise prevention strategies as well as management approaches to disease incidence and transmission.

Epigenetic mechanisms of alveolar macrophage activation in chemical-induced acute lung injury

Airways, alveoli and the pulmonary tissues are the most vulnerable to the external environment including occasional deliberate or accidental exposure to highly toxic chemical gases. However, there are many effective protective mechanisms that maintain the integrity of the pulmonary tissues and preserve lung function. Alveolar macrophages form the first line of defense against any pathogen or chemical/reactant that crosses the airway mucociliary barrier and reaches the alveolar region. Resident alveolar macrophages are activated or circulating monocytes infiltrate the airspace to contribute towards inflammatory or reparative responses. Studies on response of alveolar macrophages to noxious stimuli are rapidly emerging and alveolar macrophage are also being sought as therapeutic target. Here such studies have been reviewed and put together for a better understanding of the role pulmonary macrophages in general and alveolar macrophage in particular play in the pathogenesis of disease caused by chemical induced acute lung injury.

Single Nuclei Sequencing Reveals Intratumoral Cellular Heterogeneity and Replication Stress in Adrenocortical Carcinoma

Adrenocortical carcinoma (ACC) is a rare endocrine malignancy with a poor prognosis and limited treatment options. Bulk genomic characterization of ACC has not yielded obvious therapeutic or immunotherapeutic targets, yet novel therapies are needed. We hypothesized that elucidating the intratumoral cellular heterogeneity by single nuclei RNA sequencing analyses would yield insights into potential therapeutic vulnerabilities of this disease. In addition to characterizing the immune cell and fibroblast landscape, our analyses of single nuclei gene expression profiles identified an adrenal cortex cell cluster exhibiting a program of replication stress and DNA damage response in primary and metastatic ACC. In vitro assessment of replication stress and DNA damage response using an ACC cell line and a series of newly-derived hormonally active patient-derived tumor organoids revealed ATR sensitivity. These findings provide novel mechanistic insight into ACC biology and suggest that an underlying dependency on ATR may be leveraged therapeutically in advanced ACC.

Deep humoral profiling coupled to interpretable machine learning unveils diagnostic markers and pathophysiology of schistosomiasis

Schistosomiasis, a highly prevalent parasitic disease, affects more than 200 million people worldwide. Current diagnostics based on parasite egg detection in stool detect infection only at a late stage, and current antibody-based tests cannot distinguish past from current infection. Here, we developed and used a multiplexed antibody profiling platform to obtain a comprehensive repertoire of antihelminth humoral profiles including isotype, subclass, Fc receptor (FcR) binding, and glycosylation profiles of antigen-specific antibodies. Using Essential Regression (ER) and SLIDE, interpretable machine learning methods, we identified latent factors (context-specific groups) that move beyond biomarkers and provide insights into the pathophysiology of different stages of schistosome infection. By comparing profiles of infected and healthy individuals, we identified modules with unique humoral signatures of active disease, including hallmark signatures of parasitic infection such as elevated immunoglobulin G4 (IgG4). However, we also captured previously uncharacterized humoral responses including elevated FcR binding and specific antibody glycoforms in patients with active infection, helping distinguish them from those without active infection but with equivalent antibody titers. This signature was validated in an independent cohort. Our approach also uncovered two distinct endotypes, nonpatent infection and prior infection, in those who were not actively infected. Higher amounts of IgG1 and FcR1/FcR3A binding were also found to be likely protective of the transition from nonpatent to active infection. Overall, we unveiled markers for antibody-based diagnostics and latent factors underlying the pathogenesis of schistosome infection. Our results suggest that selective antigen targeting could be useful in early detection, thus controlling infection severity.

Nanoparticle Targeting Strategies for Lipid and Polymer-Based Gene Delivery to Immune Cells In Vivo

Lipid nanoparticles and polymeric nanoparticles are promising biomaterial platforms for robust intracellular DNA and mRNA delivery, highlighted by the widespread use of nanoparticle- (NP) based mRNA vaccines to help end the COVID-19 pandemic. Recent research has sought to adapt this nanotechnology to transfect and engineer immune cells in vivo. The immune system is an especially appealing target due to its involvement in many different diseases, and ex vivo-engineered immune cell therapies like chimeric antigen receptor (CAR) T therapy have already demonstrated remarkable clinical success in certain blood cancers. Although gene delivery can potentially address some of the cost and manufacturing concerns associated with current autologous immune cell therapies, transfecting immune cells in vivo is challenging. Not only is extrahepatic NP delivery to lymphoid organs difficult, but immune cells like T cells have demonstrated particular resistance to transfection. Despite these challenges, the modular nature of NPs allows researchers to examine critical structure-function relationships between a particle's properties and its ability to specifically engineer immune cells in vivo. Herein, several nanomaterial components are outlined, including targeting ligands, nucleic acid cargo, chemical properties, physical properties, and the route of administration to specifically target NPs to immune cells for optimal in vivo transfection.

Remodeling the hepatic immune microenvironment and demolishing T cell traps to enhance immunotherapy efficacy in liver metastasis

Immune checkpoint inhibitors (ICIs) exhibit compromised therapeutic efficacy in many patients with advanced cancers, particularly those with liver metastases. Much of this incapability can be ascribed as an irresponsiveness resulting from the "cold" hepatic tumor microenvironment that acts as T cell "traps" for which there currently lack countermeasures. We report a novel nanomedicine that converts the hepatic immune microenvironment to a "hot" phenotype by targeting hepatic macrophage-centric T cell elimination. Using the nanomedicine, composed of KIRA6 (an endothelium reticulum stress inhibitor), α-Tocopherol nanoemulsions, and anti-PD1 antibodies, we found its potency in murine models of orthotopic colorectal tumors and hepatic metastases, restoring immune responses and enhancing anti-tumor effects. A post-treatment scrutiny of the immune microenvironment landscape in the liver reveals repolarization of immunosuppressive hepatic macrophages, upregulation of Th1-like effector CD4+ T cells, and rejuvenation of dendritic cells along with CD8+ T cells. These findings suggest adaptations of liver-centric immune milieu modulation strategies to improve the efficacy of ICIs for a variety of "cold" tumors and their liver metastases.

IOS-1002, a Stabilized HLA-B57 Open Format, Exerts Potent Anti-Tumor Activity

HLA-B27 and HLA-B57 are associated with autoimmunity and long-term viral control and protection against HIV and HCV infection; however, their role in cancer immunity remains unknown. HLA class I molecules interact with innate checkpoint receptors of the LILRA, LILRB and KIR families present in diverse sets of immune cells. Here, we demonstrate that an open format (peptide free conformation) and expression- and stability-optimized HLA-B57-B2m-IgG4_Fc fusion protein (IOS-1002) binds to human leukocyte immunoglobulin-like receptor B1 and B2 (LILRB1 and LILRB2) and to killer immunoglobulin-like receptor 3DL1 (KIR3DL1). In addition, we show that the IgG4 Fc backbone is required for engagement to Fcγ receptors and potent activation of macrophage phagocytosis. IOS-1002 blocks the immunosuppressive ITIM and SHP1/2 phosphatase signaling cascade, reduces the expression of immunosuppressive M2-like polarization markers of macrophages and differentiation of monocytes to myeloid-derived suppressor cells, enhances tumor cell phagocytosis in vitro and potentiates activation of T and NK cells. Lastly, IOS-1002 demonstrates efficacy in an ex vivo patient-derived tumor sample tumoroid model. IOS-1002 is a first-in-class multi-target and multi-functional human-derived HLA molecule that activates anti-tumor immunity and is currently under clinical evaluation.

Biomarkers in sepsis

Sepsis is a life-threatening condition characterized by dysregulated host response to infection leading to organ dysfunction. Despite advances in understanding its pathology, sepsis remains a global health concern and remains a major contributor to mortality. Timely identification is crucial for improving clinical outcomes, as delayed treatment significantly impacts survival. Accordingly, biomarkers play a pivotal role in diagnosis, risk stratification, and management. This review comprehensively discusses various biomarkers in sepsis and their potential application in antimicrobial stewardship and risk assessment. Biomarkers such as white blood cell count, neutrophil to lymphocyte ratio, erythrocyte sedimentation rate, C-reactive protein, interleukin-6, presepsin, and procalcitonin have been extensively studied for their diagnostic and prognostic value as well as in guiding antimicrobial therapy. Furthermore, this review explores the role of biomarkers in risk stratification, emphasizing the importance of identifying high-risk patients who may benefit from specific therapeutic interventions. Moreover, the review discusses the emerging field of transcriptional diagnostics and metagenomic sequencing. Advances in sequencing have enabled the identification of host response signatures and microbial genomes, offering insight into disease pathology and aiding species identification. In conclusion, this review provides a comprehensive overview of the current understanding and future directions of biomarker-based approaches in sepsis diagnosis, management, and personalized therapy.

LINC00998 Modulating M2 Macrophage Activation in Allergic Rhinitis by Stabilizing BOB.1 mRNA

Background

Allergic rhinitis (AR) is globally recognized as a considerable threat to human health with a rising prevalence and a substantial medical and socioeconomic burden. Numerous studies have emphasized the significance of long noncoding RNAs (lncRNAs) in allergic responses. Hence, this research dealt with exploring the involvement of the lncRNA LINC00998 in the mechanism of AR.

Methods

LINC00998 expression was assessed by qRT-PCR in peripheral blood mononuclear cells acquired from individuals with AR. Additionally, the potential relationship between LINC00998 and macrophage polarization was observed in vitro. Then we constructed AR mice model and macrophage polarization models using THP-1 cells as well as primary human macrophages to verify the M2 shift in AR and the low expression level of LINC00998 in M2 macrophages. We used gain- and loss-of-function experiments to explore the modification of LINC00998 in macrophage polarization. Furthermore, we explored the underlying mechanism of LINC00998 mediates through qRT-PCR, flow cytometry, and Western blot.

Results

The analysis revealed a significant decrease in LINC00998 expression in the samples obtained from patients with AR. LINC00998 is markedly increased in M1 macrophages whereas decreased in M2 macrophages in vitro. Furthermore, suppression of LINC00998 caused a remarkable enhancement in M2 polarization, whereas its overexpression led to its attenuation. Knockdown of LINC00998 led to a remarkable downregulation of BOB.1 mRNA and protein, while overexpression of LINC00998 upregulated their expression. Moreover, it was found that BOB.1 modulated macrophage polarization through the PU.1/IL-1β axis. Meanwhile, the modulation of LINC00098 overexpression on macrophage polarization and PU.1/ IL-1β can be reversed by BOB.1 siRNA.

Conclusion

This research revealed the lncRNA LINC00998 altered M2 macrophage polarization by regulating the BOB.1/PU.1/IL-1β axis, which open up new avenues for studying the pathogenesis of AR.

A Lacticaseibacillus rhamnosus secretome induces immunoregulatory transcriptional, functional and immunometabolic signatures in human THP-1 monocytes

Macrophage responses to activation are fluid and dynamic in their ability to respond appropriately to challenges, a role integral to host defence. While bacteria can influence macrophage differentiation and polarization into pro-inflammatory and alternatively activated phenotypes through direct interactions, many questions surround indirect communication mechanisms mediated through secretomes derived from gut bacteria, such as lactobacilli. We examined effects of secretome-mediated conditioning on THP-1 human monocytes, focusing on the ability of the Lacticaseibacillus rhamnosus R0011 secretome (LrS) to drive macrophage differentiation and polarization and prime immune responses to subsequent challenge with lipopolysaccharide (LPS). Genome-wide transcriptional profiling revealed increased M2-associated gene transcription in response to LrS conditioning in THP-1 cells. Cytokine and chemokine profiling confirmed these results, indicating increased M2-associated chemokine and cytokine production (IL-1Ra, IL-10). These cells had increased cell-surface marker expression of CD11b, CD86, and CX3CR1, coupled with reduced expression of the M1 macrophage-associated marker CD64. Mitochondrial substrate utilization assays indicated diminished reliance on glycolytic substrates, coupled with increased utilization of citric acid cycle intermediates, characteristics of functional M2 activity. LPS challenge of LrS-conditioned THP-1s revealed heightened responsiveness, indicative of innate immune priming. Resting stage THP-1 macrophages co-conditioned with LrS and retinoic acid also displayed an immunoregulatory phenotype with expression of CD83, CD11c and CD103 and production of regulatory cytokines. Secretome-mediated conditioning of macrophages into an immunoregulatory phenotype is an uncharacterized and potentially important route through which lactic acid bacteria and the gut microbiota may train and shape innate immunity at the gut-mucosal interface.

Identification of CD64 as a marker for the destructive potential of synovitis in osteoarthritis

OBJECTIVES

OA is characterized by cartilage degeneration and persistent pain. The majority of OA patients present with synovitis, which is associated with increased cartilage damage. Activated synovial macrophages are key contributors to joint destruction. Therefore, a marker that reflects the activation of these cells could be a valuable tool to characterize the destructive potential of synovitis and benefit monitoring of OA. Here, we aimed to investigate the use of CD64 (FcγRI) as a marker to characterize the damaging potential of synovitis in OA.

METHODS

Synovial biopsies were obtained from end-stage OA patients that underwent joint replacement surgery. CD64 protein expression and localization was evaluated using immunohistochemistry and immunofluorescence and quantified using flow cytometry. qPCR was performed to measure the expression of FCGR1 and OA-related genes in synovial biopsies, and in primary chondrocytes and primary fibroblasts stimulated with OA conditioned medium (OAS-CM).

RESULTS

Our data exposed a wide range of CD64 expression in OA synovium and showed positive correlations between FCGR1 and S100A8, S100A9, IL1B, IL6 and MMP1/2/3/9/13 expression. CD64 protein correlated with MMP1, MMP3, MMP9, MMP13 and S100A9. Furthermore, we observed that synovial CD64 protein levels in source tissue for OAS-CM significantly associated with the OAS-CM-induced expression of MMP1, MMP3 and especially ADAMTS4 in cultured fibroblasts, but not chondrocytes.

CONCLUSION

Together, these results indicate that synovial CD64 expression is associated with the expression of proteolytic enzymes and inflammatory markers related to structural damage in OA. CD64 therefore holds promise as marker to characterize the damaging potential of synovitis.

CD64 plays a key role in diabetic wound healing

Introduction

Wound healing poses a clinical challenge in diabetes mellitus (DM) due to compromised host immunity. CD64, an IgG-binding Fcgr1 receptor, acts as a pro-inflammatory mediator. While its presence has been identified in various inflammatory diseases, its specific role in wound healing, especially in DM, remains unclear.

Objectives

We aimed to investigate the involvement of CD64 in diabetic wound healing using a DM animal model with CD64 KO mice.

Methods

First, we compared CD64 expression in chronic skin ulcers from human DM and non-DM skin. Then, we monitored wound healing in a DM mouse model over 10 days, with or without CD64 KO, using macroscopic and microscopic observations, as well as immunohistochemistry.

Results

CD64 expression was significantly upregulated (1.25-fold) in chronic ulcerative skin from DM patients compared to non-DM individuals. Clinical observations were consistent with animal model findings, showing a significant delay in wound healing, particularly by day 7, in CD64 KO mice compared to WT mice. Additionally, infiltrating CD163+ M2 macrophages in the wounds of DM mice decreased significantly compared to non-DM mice over time. Delayed wound healing in DM CD64 KO mice correlated with the presence of inflammatory mediators.

Conclusion

CD64 seems to play a crucial role in wound healing, especially in DM conditions, where it is associated with CD163+ M2 macrophage infiltration. These data suggest that CD64 relies on host immunity during the wound healing process. Such data may provide useful information for both basic scientists and clinicians to deal with diabetic chronic wound healing.

A Versatile Intestine-on-Chip System for Deciphering the Immunopathogenesis of Inflammatory Bowel Disease

The multifactorial nature of inflammatory bowel disease (IBD) necessitates reliable and practical experimental models to elucidate its etiology and pathogenesis. To model the intestinal microenvironment at the onset of IBD in vitro, it is important to incorporate relevant cellular and noncellular components before inducing stepwise pathogenic developments. A novel intestine-on-chip system for investigating multiple aspects of IBD's immunopathogenesis is presented. The system includes an array of tight and polarized barrier models formed from intestinal epithelial cells on an in-vivo-like subepithelial matrix within one week. The dynamic remodeling of the subepithelial matrix by cells or their secretome demonstrates the physiological relevance of the on-chip barrier models. The system design enables introduction of various immune cell types and inflammatory stimuli at specific locations in the same barrier model, which facilitates investigations of the distinct roles of each cell type in intestinal inflammation development. It is showed that inflammatory behavior manifests in an upregulated expression of inflammatory markers and cytokines (TNF-α). The neutralizing effect of the anti-inflammatory antibody Infliximab on levels of TNF-α and its inducible cytokines could be explicitly shown. Overall, an innovative approach to systematically developing a microphysiological system to comprehend immune-system-mediated disorders of IBD and to identify new therapeutic strategies is presented.

NAAA-regulated lipid signaling in monocytes controls the induction of hyperalgesic priming in mice

Circulating monocytes participate in pain chronification but the molecular events that cause their deployment are unclear. Using a mouse model of hyperalgesic priming (HP), we show that monocytes enable progression to pain chronicity through a mechanism that requires transient activation of the hydrolase, N-acylethanolamine acid amidase (NAAA), and the consequent suppression of NAAA-regulated lipid signaling at peroxisome proliferator-activated receptor-α (PPAR-α). Inhibiting NAAA in the 72 hours following administration of a priming stimulus prevented HP. This effect was phenocopied by NAAA deletion and depended on PPAR-α recruitment. Mice lacking NAAA in CD11b+ cells - monocytes, macrophages, and neutrophils - were resistant to HP induction. Conversely, mice overexpressing NAAA or lacking PPAR-α in the same cells were constitutively primed. Depletion of monocytes, but not resident macrophages, generated mice that were refractory to HP. The results identify NAAA-regulated signaling in monocytes as a control node in the induction of HP and, potentially, the transition to pain chronicity.

Hyperthermia in Combination with Emerging Targeted and Immunotherapies as a New Approach in Cancer Treatment

Despite significant advancements in the development of novel therapies, cancer continues to stand as a prominent global cause of death. In many cases, the cornerstone of standard-of-care therapy consists of chemotherapy (CT), radiotherapy (RT), or a combination of both. Notably, hyperthermia (HT), which has been in clinical use in the last four decades, has proven to enhance the effectiveness of CT and RT, owing to its recognized potency as a sensitizer. Furthermore, HT exerts effects on all steps of the cancer-immunity cycle and exerts a significant impact on key oncogenic pathways. Most recently, there has been a noticeable expansion of cancer research related to treatment options involving immunotherapy (IT) and targeted therapy (TT), a trend also visible in the research and development pipelines of pharmaceutical companies. However, the potential results arising from the combination of these innovative therapeutic approaches with HT remain largely unexplored. Therefore, this review aims to explore the oncology pipelines of major pharmaceutical companies, with the primary objective of identifying the principal targets of forthcoming therapies that have the potential to be advantageous for patients by specifically targeting molecular pathways involved in HT. The ultimate goal of this review is to pave the way for future research initiatives and clinical trials that harness the synergy between emerging IT and TT medications when used in conjunction with HT.

Bridging Retinal and Cerebral Neurodegeneration: A Focus on Crosslinks between Alzheimer-Perusini's Disease and Retinal Dystrophies

In the early stages of Alzheimer-Perusini's disease (AD), individuals often experience vision-related issues such as color vision impairment, reduced contrast sensitivity, and visual acuity problems. As the disease progresses, there is a connection with glaucoma and age-related macular degeneration (AMD) leading to retinal cell death. The retina's involvement suggests a link with the hippocampus, where most AD forms start. A thinning of the retinal nerve fiber layer (RNFL) due to the loss of retinal ganglion cells (RGCs) is seen as a potential AD diagnostic marker using electroretinography (ERG) and optical coherence tomography (OCT). Amyloid beta fragments (Aβ), found in the eye's vitreous and aqueous humor, are also present in the cerebrospinal fluid (CSF) and accumulate in the retina. Aβ is known to cause tau hyperphosphorylation, leading to its buildup in various retinal layers. However, diseases like AD are now seen as mixed proteinopathies, with deposits of the prion protein (PrP) and α-synuclein found in affected brains and retinas. Glial cells, especially microglial cells, play a crucial role in these diseases, maintaining immunoproteostasis. Studies have shown similarities between retinal and brain microglia in terms of transcription factor expression and morphotypes. All these findings constitute a good start to achieving better comprehension of neurodegeneration in both the eye and the brain. New insights will be able to bring the scientific community closer to specific disease-modifying therapies.

Design, optimization, production and activity testing of recombinant immunotoxins expressed in plants and plant cells for the treatment of monocytic leukemia

Antibody-drug conjugates (ADCs) can improve therapeutic indices compared to plain monoclonal antibodies (mAbs). However, ADC synthesis is complex because the components are produced separately in CHO cells (mAb) and often by chemical synthesis (drug). They are individually purified, coupled, and then the ADC is purified, increasing production costs compared to regular mAbs. In contrast, it is easier to produce recombinant fusion proteins consisting of an antibody derivative, linker and proteinaceous toxin, i.e. a recombinant immunotoxin (RIT). Plants are capable of the post-translational modifications needed for functional antibodies and can also express active protein toxins such as the recombinant mistletoe lectin viscumin, which is not possible in prokaryotes and mammalian cells respectively. Here, we used Nicotiana benthamiana and N. tabacum plants as well as tobacco BY-2 cell-based plant cell packs (PCPs) to produce effective RITs targeting CD64 as required for the treatment of myelomonocytic leukemia. We compared RITs with different subcellular targeting signals, linkers, and proteinaceous toxins. The accumulation of selected candidates was improved to ~ 40 mg kg-1 wet biomass using a design of experiments approach, and corresponding proteins were isolated with a purity of ~ 80% using an optimized affinity chromatography method with an overall yield of ~ 84%. One anti-CD64 targeted viscumin-based drug candidate was characterized in terms of storage stability and cytotoxicity test in vitro using human myelomonocytic leukemia cell lines. We identified bottlenecks in the plant-based expression platform that require further improvement and assessed critical process parameters that should be considered during process development for plant-made RITs.

Targeted Delivery of the Pan-Inflammasome Inhibitor MM01 as an Alternative Approach to Acute Lung Injury Therapy

Acute lung injury (ALI) is a severe pulmonary disorder responsible for high percentage of mortality and morbidity in intensive care unit patients. Current treatments are ineffective, so the development of efficient and specific therapies is an unmet medical need. The activation of NLPR3 inflammasome during ALI produces the release of proinflammatory factors and pyroptosis, a proinflammatory form of cell death that contributes to lung damage spreading. Herein, it is demonstrated that modulating inflammasome activation through inhibition of ASC oligomerization by the recently described MM01 compound can be an alternative pharmacotherapy against ALI. Besides, the added efficacy of using a drug delivery nanosystem designed to target the inflamed lungs is determined. The MM01 drug is incorporated into mesoporous silica nanoparticles capped with a peptide (TNFR-MM01-MSNs) to target tumor necrosis factor receptor-1 (TNFR-1) to proinflammatory macrophages. The prepared nanoparticles can deliver the cargo in a controlled manner after the preferential uptake by proinflammatory macrophages and exhibit anti-inflammatory activity. Finally, the therapeutic effect of MM01 free or nanoparticulated to inhibit inflammatory response and lung injury is successfully demonstrated in lipopolysaccharide-mouse model of ALI. The results suggest the potential of pan-inflammasome inhibitors as candidates for ALI therapy and the use of nanoparticles for targeted lung delivery.

The Potential Role of C-Reactive Protein in Metabolic-Dysfunction-Associated Fatty Liver Disease and Aging

Nonalcoholic fatty liver disease (NAFLD), recently redefined as metabolic-dysfunction-associated fatty liver disease (MASLD), is liver-metabolism-associated steatohepatitis caused by nonalcoholic factors. NAFLD/MASLD is currently the most prevalent liver disease in the world, affecting one-fourth of the global population, and its prevalence increases with age. Current treatments are limited; one important reason hindering drug development is the insufficient understanding of the onset and pathogenesis of NAFLD/MASLD. C-reactive protein (CRP), a marker of inflammation, has been linked to NAFLD and aging in recent studies. As a conserved acute-phase protein, CRP is widely characterized for its host defense functions, but the link between CRP and NAFLD/MASLD remains unclear. Herein, we discuss the currently available evidence for the involvement of CRP in MASLD to identify areas where further research is needed. We hope this review can provide new insights into the development of aging-associated NAFLD biomarkers and suggest that modulation of CRP signaling is a potential therapeutic target.

Intravenous Administration of Human Umbilical Cord Mesenchymal Stromal Cells Leads to an Inflammatory Response in the Lung

Mesenchymal stromal cells (MSCs) administered intravenously (IV) have shown efficacy in preclinical models of various diseases. This is despite the cells not reaching the site of injury due to entrapment in the lungs. The immunomodulatory properties of MSCs are thought to underlie their therapeutic effects, irrespective of whether they are sourced from bone marrow, adipose tissue, or umbilical cord. To better understand how MSCs affect innate immune cell populations in the lung, we evaluated the distribution and phenotype of neutrophils, monocytes, and macrophages by flow cytometry and histological analyses after delivering human umbilical cord-derived MSCs (hUC-MSCs) IV into immunocompetent mice. After 2 hr, we observed a significant increase in neutrophils, and proinflammatory monocytes and macrophages. Moreover, these immune cells localized in close proximity to the MSCs, suggesting an active role in their clearance. By 24 hr, we detected an increase in anti-inflammatory monocytes and macrophages. These results suggest that the IV injection of hUC-MSCs leads to an initial inflammatory phase in the lung shortly after injection, followed by a resolution phase 24 hr later.

T cells with split CARs specific for NKG2D ligands and PD-L1 exhibit improved selectivity towards monocyte-derived cells while effective in eliminating acute myeloid leukaemia in vivo

PURPOSE

The expression of NKG2D ligands and PD-L1 has been detected on acute myeloid leukaemia (AML) cells, as well as normal cells of the myeloid lineage. To target leukemic cells while minimizing collateral damage to normal cells, we constructed a split dual CAR system based on the AND-gate logic.

METHODS

The NKG2D extracellular domain linked with DAP12 without a co-stimulatory signal was used for the basal activation of T cells, and used together with the PD-L1-specific chimeric costimulatory receptor containing the 4-1BB activating domain for co-stimulatory signal 2 input. This dual CAR displayed cell-type specificity and activity similar as a 2nd generation NKG2D ligand-specific CAR.

RESULTS

When compared to CD64 and PD-L1-specific 2nd generation CARs, we observed that the split dual CAR offered an improved myeloid cell type selectivity. For example, PD-L1-specific CAR-T cells lysed all tested myeloid cell types that expressed PD-L1, including M0 macrophages (Mø0), LPS-polarized Mø1, IFN-γ polarized Mø1, IL-4 polarized Mø2, monocytes, immature dendritic cells (imDCs), mature DCs, as well as KG-1 AML cells, while the dual CAR-T cells displaying killing activity only towards LPS polarized Mø1, mature DCs and KG-1 cells that expressed both NKG2D ligands and PD-L1. In a mouse liquid tumor model, the dual CAR-T cells were effective in eradicating established KG-1 AML xenografts.

CONCLUSION

The improved cell type specificity offered by our split dual CAR-T cell system targeting paired antigens would favour the reduction of the on-target off-tumor toxicity towards normal myeloid cells during the treatment of myeloid leukaemia.

CD64 as novel molecular imaging marker for the characterization of synovitis in rheumatoid arthritis

BACKGROUND

Rheumatoid arthritis (RA) is one of the most prevalent and debilitating joint diseases worldwide. RA is characterized by synovial inflammation (synovitis), which is linked to the development of joint destruction. Magnetic resonance imaging and ultrasonography are widely being used to detect the presence and extent of synovitis. However, these techniques do not reveal the activation status of inflammatory cells such as macrophages that play a crucial role in synovitis and express CD64 (Fc gamma receptor (FcγR)I) which is considered as macrophage activation marker.

OBJECTIVES

We aimed to investigate CD64 expression and its correlation with pro-inflammatory cytokines and pro-damaging factors in human-derived RA synovium. Furthermore, we aimed to set up a molecular imaging modality using a radiolabeled CD64-specific antibody as a novel imaging tracer that could be used to determine the extent and phenotype of synovitis using optical and nuclear imaging.

METHODS

First, we investigated CD64 expression in synovium of early- and late-stage RA patients and studied its correlation with the expression of pro-inflammatory and tissue-damaging factors. Next, we conjugated an anti-CD64 antibody with IRDye 800CW and diethylenetriamine penta-acetic acid (DTPA; used for 111In labeling) and tested its binding on cultured THP1 cells, ex vivo RA synovium explants and its imaging potential in SCID mice implanted with human RA synovium explants obtained from RA patients who underwent total joint replacement.

RESULTS

We showed that CD64 is expressed in synovium of early and late-stage RA patients and that FCGR1A/CD64 expression is strongly correlated with factors known to be involved in RA progression. Combined, this makes CD64 a useful marker for imaging the extent and phenotype of synovitis. We reported higher binding of the [111In]In-DTPA-IRDye 800CW anti-CD64 antibody to in vitro cultured THP1 monocytes and ex vivo RA synovium compared to isotype control. In human RA synovial explants implanted in SCID mice, the ratio of uptake of the antibody in synovium over blood was significantly higher when injected with anti-CD64 compared to isotype and injecting an excess of unlabeled antibody significantly reduced the antibody-binding associated signal, both indicating specific receptor binding.

CONCLUSION

Taken together, we successfully developed an optical and nuclear imaging modality to detect CD64 in human RA synovium in vivo.

Angiotensin II modulates THP-1-like macrophage phenotype and inflammatory signatures via angiotensin II type 1 receptor

Angiotensin II (Ang II) is a major component of the renin-angiotensin or renin-angiotensin-aldosterone system, which is the main element found to be involved in cardiopathology. Recently, long-term metabolomics studies have linked high levels of angiotensin plasma to inflammatory conditions such as coronary heart disease, obesity, and type 2 diabetes. Monocyte/macrophage cellular function and phenotype orchestrate the inflammatory response in various pathological conditions, most notably cardiometabolic disease. An activation of the Ang II system is usually associated with inflammation and cardiovascular disease; however, the direct effect on monocyte/macrophages has still not been well elucidated. Herein, we have evaluated the cellular effects of Ang II on THP-1-derived macrophages. Ang II stimulated the expression of markers involved in monocyte/macrophage cell differentiation (e.g., CD116), as well as adhesion, cell-cell interaction, chemotaxis, and phagocytosis (CD15, CD44, CD33, and CD49F). Yet, Ang II increased the expression of proinflammatory markers (HLA-DR, TNF-α, CD64, CD11c, and CD38) and decreased CD206 (mannose receptor), an M2 marker. Moreover, Ang II induced cytosolic calcium overload, increased reactive oxygen species, and arrested cells in the G1 phase. Most of these effects were induced via the angiotensin II type 1 receptor (AT1R). Collectively, our results provide new evidence in support of the effect of Ang II in inflammation associated with cardiometabolic diseases.

Injectable liposomal docosahexaenoic acid alleviates atherosclerosis progression and enhances plaque stability

Atherosclerosis is a chronic inflammatory vascular disease that is characterized by the accumulation of lipids and immune cells in plaques built up inside artery walls. Docosahexaenoic acid (DHA, 22:6n-3), an omega-3 polyunsaturated fatty acid (PUFA), which exerts anti-inflammatory and antioxidant properties, has long been purported to be of therapeutic benefit to atherosclerosis patients. However, large clinical trials have yielded inconsistent data, likely due to variations in the formulation, dosage, and bioavailability of DHA following oral intake. To fully exploit its potential therapeutic effects, we have developed an injectable liposomal DHA formulation intended for intravenous administration as a plaque-targeted nanomedicine. The liposomal formulation protects DHA against chemical degradation and increases its local concentration within atherosclerotic lesions. Mechanistically, DHA liposomes are readily phagocytosed by activated macrophages, exert potent anti-inflammatory and antioxidant effects, and inhibit foam cell formation. Upon intravenous administration, DHA liposomes accumulate preferentially in atherosclerotic lesional macrophages and promote polarization of macrophages towards an anti-inflammatory M2 phenotype, resulting in attenuation of atherosclerosis progression in both ApoE-/- and Ldlr-/- experimental models. Plaque composition analysis demonstrates that liposomal DHA inhibits macrophage infiltration, reduces lipid deposition, and increases collagen content, thus improving the stability of atherosclerotic plaques against rupture. Matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) further reveals that DHA liposomes can partly restore the complex lipid profile of the plaques to that of early-stage plaques. In conclusion, DHA liposomes offer a promising approach for applying DHA to stabilize atherosclerotic plaques and attenuate atherosclerosis progression, thereby preventing atherosclerosis-related cardiovascular events.

Chamomile essential oils exert anti-inflammatory effects involving human and murine macrophages: Evidence to support a therapeutic action

ETHNOPHARMACOLOGICAL RELEVANCE

Chamomile (M. chamomilla L.) is an herbaceous plant from family Astereaceae, that has a long history of use in traditional medicine. It has been used as herbal remedies for thousands of years to treat several diseases, including infections, neuropsychiatric, respiratory, gastrointestinal, and liver disorders. Chronic inflammation is involved in the pathogenesis of most infectious and non-infectious diseases and macrophages are considered the major cellular players that drive disease initiation and maintenance.

AIM OF THE STUDY

The aim of this study was to evaluate the variation in the chemical profile of the essential oil of M. chamomilla plants collected in three experimental field sites in the Molise region. Additionally, we evaluated the pharmacological mechanism behind the anti-inflammatory effect of M. chamomilla essential oils.

MATERIAL AND METHODS

Three essential oils (called GC1, GC2 and GC3) were extracted from aerial parts of M. chamomilla by hydrodistillation and chemical composition was analyzed by gas chromatography-mass spectrometry (GC-MS). The essential oils were tested for their ability to modulate pro-inflammatory murine macrophages and human peripheral blood mononuclear cells (PBMCs) functions.

RESULTS

The chemical analysis of the samples revealed the presence of a high content of the oxygenated sesquiterpenes that represented more than the half of the entire oils. GC1, GC2 and GC3 essential oils significantly attenuated LPS/IFN-γ-induced inflammation by reducing M1 polarization. In details, they showed significant anti-inflammatory property by inhibiting NO, TNF-α and IL-6 production. These effects were correlated to a suppression of LPS-mediated p65 activation, the critical transactivation subunit for NF-κB transcription factor. Oxidative stress may trigger macrophages activation and elicit strong immune responses. Our study demonstrated that GC1, GC2 and GC3 were highly effective at increasing GCL and HMOX-1 anti-oxidant enzymes expression leading to the rapid scavenging of ROS. The antioxidant activity of these oils was explained throughout the activation of NRF2 signaling pathway. Next, we demonstrated that essential oils were able to reduce CD4⁺ T cell activation which are also involved in inflammatory processes.

CONCLUSIONS

Our data describe for the first time that chamomile essential oils exerted their anti-inflammatory and antioxidant activity by modulating macrophages and CD4⁺ T cells-mediate immune response.

HLA-DR Expression on Monocytes and Sepsis Index Are Useful in Predicting Sepsis

The reduction of mortality in patients with sepsis depends on the early identification and treatment of at-risk patients. The aim was to evaluate the HLA-DR expression on the surface of monocytes (_MHLA-DR ratio), the sepsis index (CD64 expression on neutrophils/_MHLA-DR ratio), and C-reactive protein (CRP) with the development of sepsis. We prospectively enrolled 77 critically ill patients, 59 with stroke and 18 with traumatic brain injuries. The biomarkers were tested at the baseline and 3, 6, 9, 12, and 15 days later. Most patients (71%) developed sepsis (4.2 ± 1.3 days after admission). On day 3, those subsequently developing sepsis had lower levels of _MHLA-DR+ (81.7 ± 16.2% vs. 88.5 ± 12.1%, p < 0.05) and higher sepsis indexes (0.19 ± 0.19 vs. 0.08 ± 0.08, p < 0.01) than those not developing sepsis. The _MHLA-DR ratio slowly recovered before day 6, while the sepsis index remained raised in septic patients up to day 9 (p < 0.05). To predict the development of sepsis, optimal cut-offs were CRP levels > 106.90 mg/mL (74.19% sensitivity, 69.49 specificity) and _MHLA-DR expression rate < 72.80% (45.31% sensitivity, 89.47% specificity). The periodic monitoring of the _MHLA-DR expression together with CRP and sepsis index may help to identify patients in the ICU at increased risk of developing sepsis.

In Vitro Functional Characterization of Type-I Taste Bud Cells as Monocytes/Macrophages-like Which Secrete Proinflammatory Cytokines

The sense of taste determines the choice of nutrients and food intake and, consequently, influences feeding behaviors. The taste papillae are primarily composed of three types of taste bud cells (TBC), i.e., type I, type II, and type III. The type I TBC, expressing GLAST (glutamate--aspartate transporter), have been termed as glial-like cells. We hypothesized that these cells could play a role in taste bud immunity as glial cells do in the brain. We purified type I TBC, expressing F4/80, a specific marker of macrophages, from mouse fungiform taste papillae. The purified cells also express CD11b, CD11c, and CD64, generally expressed by glial cells and macrophages. We further assessed whether mouse type I TBC can be polarized toward M1 or M2 macrophages in inflammatory states like lipopolysaccharide (LPS)-triggered inflammation or obesity, known to be associated with low-grade inflammation. Indeed, LPS-treatment and obesity state increased TNFα, IL-1β, and IL-6 expression, both at mRNA and protein levels, in type I TBC. Conversely, purified type I TBC treated with IL-4 showed a significant increase in arginase 1 and IL-4. These findings provide evidence that type I gustatory cells share many features with macrophages and may be involved in oral inflammation.

Polymers and Bioactive Compounds with a Macrophage Modulation Effect for the Rational Design of Hydrogels for Skin Regeneration

The development of biomaterial platforms for dispensing reagents of interest such as antioxidants, growth factors or antibiotics based on functional hydrogels represents a biotechnological solution for many challenges that the biomedicine field is facing. In this context, in situ dosing of therapeutic components for dermatological injuries such as diabetic foot ulcers is a relatively novel strategy to improve the wound healing process. Hydrogels have shown more comfort for the treatment of wounds due to their smooth surface and moisture, as well as their structural affinity with tissues in comparison to hyperbaric oxygen therapy, ultrasound, and electromagnetic therapies, negative pressure wound therapy or skin grafts. Macrophages, one of the most important cells of the innate immune system, have been described as the key not only in relation to the host immune defense, but also in the progress of wound healing. Macrophage dysfunction in chronic wounds of diabetic patients leads to a perpetuating inflammatory environment and impairs tissue repair. Modulating the macrophage phenotype from pro-inflammatory (M1) to anti-inflammatory (M2) could be a strategy for helping to improve chronic wound healing. In this regard, a new paradigm is found in the development of advanced biomaterials capable of inducing in situ macrophage polarization to offer an approach to wound care. Such an approach opens a new direction for the development of multifunctional materials in regenerative medicine. This paper surveys emerging hydrogel materials and bioactive compounds being investigated to induce the immunomodulation of macrophages. We propose four potential functional biomaterials for wound healing applications based on novel biomaterial/bioactive compound combination that are expected to show synergistic beneficial outcomes for the local differentiation of macrophages (M1-M2) as a therapeutic strategy for chronic wound healing improvement.

The relationship of D. pteronyssinus allergic component sIgE and sIgG₄ in house dust mite allergic rhinitis or/and allergic asthma patients

Objective: House-dust mite sensitization is an important cause of allergic asthma and/or rhinitis in southern China. This study aimed to analyze the immune effect and relationship between the Dermatophagoides pteronyssinus components specific immunoglobulin E (sIgE) and sIgG₄. Methods: The serum levels of sIgE and sIgG₄ to D. pteronyssinus allergen components Der p 1, 2, 3, 5, 7, 10, and 23 were detected in 112 patients with allergic rhinitis (AR) and/or allergic asthma (AA). Results: Overall, Der p 1 had the highest positive rate of sIgE (72.3%), followed by Der p 2 (65.2%) and Der p 23 (46.4%). Meanwhile, the highest positive rates of sIgG₄ were for Der p 2 (47.3%), Der p 1 (33.0%), and Der p 23 (25.0%). The patients with AR and AA had a higher positive rate (43.4%) of sIgG₄ than that in the patients with AR (42.4%) and the patients with AA (20.4%; p = 0.043). In patients with AR, the positive rate of sIgE in Der p 1 (84.8%) was higher than that in sIgG₄ (42.4%; p = 0.037), but the positive rate of sIgG₄ in Der p 10 (21.2%) was higher than that in sIgE (18.2%; p < 0.001). Most of the patients were positive for sIgE and sIgG₄ of Der p 2 and Der p 10 at the same time. However, positive results for sIgE alone were just found in Der p 7 and Der p 21. Optimal scale analysis showed that Der p 2, Der p 7, and Der p 21 sIgG₄ were closely related to AR and AA (Cronbach α = 0.917). Conclusion: Herein, the D. pteronyssinus allergen components showed different characteristics among the patients with AR, patients with AA, and patients with AR and AA in southern China. Thus, sIgG₄ may be play an important role in allergic reactions.

Macrophage Phenotyping in Atherosclerosis by Proteomics

Macrophages are heterogeneous and plastic cells, able to adapt their phenotype and functions to changes in the microenvironment. They are involved in several homeostatic processes and also in many human diseases, including atherosclerosis, where they participate in all the stages of the disease. For these reasons, macrophages have been studied extensively using different approaches, including proteomics. Proteomics, indeed, may be a powerful tool to better understand the behavior of these cells, and a careful analysis of the proteome of different macrophage phenotypes can help to better characterize the role of these phenotypes in atherosclerosis and provide a broad view of proteins that might potentially affect the course of the disease. In this review, we discuss the different proteomic techniques that have been used to delineate the proteomic profile of macrophage phenotypes and summarize some results that can help to elucidate the roles of macrophages and develop new strategies to counteract the progression of atherosclerosis and/or promote regression.

Single-cell atlas reveals different immune environments between stable and vulnerable atherosclerotic plaques

Introduction

Regardless of the degree of stenosis, vulnerable plaque is an important cause of ischemic stroke and thrombotic complications. The changes of the immune microenvironment within plaques seem to be an important factor affecting the characteristics of the plaque. However, the differences of immune microenvironment between stable and vulnerable plaques were remained unknown.

Methods

In this study, RNA-sequencing was performed on superficial temporal arteries from 5 traumatic patients and plaques from 3 atherosclerotic patients to preliminary identify the key immune response processes in plaques. Mass cytometry (CyTOF) technology was used to explore differences in immune composition between 9 vulnerable plaques and 12 stable plaques. Finally, immunofluorescence technique was used to validate our findings in the previous analysis.

Results

Our results showed that more CD86+CD68+ M1 pro-inflammatory macrophages were found in vulnerable plaques, while CD4+T memory cells were mainly found in stable plaques. In addition, a CD11c+ subset of CD4+T cells with higher IFN-r secretion was found within the vulnerable plaque. In two subsets of B cells, CD19+CD20-B cells in vulnerable plaques secreted more TNF-a and IL-6, while CD19-CD20+B cells expressed more PD-1 molecules.

Conclusion

In conclusion, our study suggested that M1-like macrophages are the major cell subset affecting plaque stability, while functional B cells may also contribute to plaque stability.

FcγRI FG-loop functions as a pH sensitive switch for IgG binding and release

Understanding the molecular mechanism underlying the hierarchic binding between FcγRs and IgG antibodies is critical for therapeutic antibody engineering and FcγR functions. The recent determination of crystal structures of FcγRI-Fc complexes, however, resulted in two controversial mechanisms for the high affinity receptor binding to IgG. Here, we describe high resolution structures of a bovine FG-loop variant of FcγRI in complex with the Fc fragment of IgG₁ crystallized in three different conditions at neutral pH, confirming the characteristic FG loop-Fc interaction is critical to the high affinity immunoglobulin binding. We showed that the FcγRI D2-domain FG-loop functioned as a pH-sensing switch for IgG binding. Further live cell imaging of FcγRI-mediated internalization of immune complexes showed a pH sensitive temporal-spatial antibody-antigen uptake and release. Taken together, we demonstrate that the structures of FcγRI-Fc crystallized at neutral and acidic pH, respectively, represent the high and low affinity binding states of the receptor for IgG uptake and release. These results support a role for FcγRI in antigen delivery, highlight the importance of Fc glycan in antibody binding to the high affinity receptor and provide new insights to future antibody engineering.

Identification of Key Gene Targets for Periodontitis Treatment by Bioinformatics Analysis

Background. Periodontitis is considered to be the leading cause of tooth loss in adults, and it interacts with some serious systemic diseases. Periodontal basic therapy is the cornerstone of periodontal disease treatment and long-term maintenance and has a positive impact on the treatment of systemic diseases. Aim. To explore the potential gene targets of periodontitis therapies by bioinformatics method. Methods. We analyzed the expression database (GSE6751) downloaded from the Gene Expression Omnibus (GEO) with weighted gene coexpression network analysis (WGCNA) to confirm the functional gene modules. Pathway enrichment network analyses the key genes in functional modules and verified the candidate genes from the samples in peripheral blood sources of GSE43525. Moreover, we confirmed the expression of target protein in the periodontal tissues of experimental periodontitis-afflicted mice using western blotting. Results. The functional gene modules were found to have biological processes, and ARRB2, BIRC3, CD14, DYNLL1, FCER1G, FCGR1A, FCGR2B, FGR, HCK, and PRKCD were screened as candidates’ genes in functional modules. The 921 DEG from GSE43525 and 418 DEG is from the green module of GSE6751 and identified AMICA1, KDELR1, DHRS7B, LMNB1, CTSA, S100A12, and FCGR1A as target genes. Finally, FCGR1A (CD64) was confirmed as the key gene that affects periodontal treatment. Western blot analysis showed an increasing trend in the expression level of FCGR1A protein in the periodontal tissues of experimental periodontitis mice compared to normal mice. Conclusions. FCGR1A (CD64) may be a key gene target for periodontal therapy in patients with periodontitis and other systemic diseases.

Hepatic damage caused by long-term high cholesterol intake induces a dysfunctional restorative macrophage population in experimental NASH

Excessive dietary cholesterol is preferentially stored in the liver, favoring the development of nonalcoholic steatohepatitis (NASH), characterized by progressive hepatic inflammation and fibrosis. Emerging evidence indicates a critical contribution of hepatic macrophages to NASH severity. However, the impact of cholesterol on these cells in the setting of NASH remains elusive. Here, we demonstrate that the dietary cholesterol content directly affects hepatic macrophage global gene expression. Our findings suggest that the modifications triggered by prolonged high cholesterol intake induce long-lasting hepatic damage and support the expansion of a dysfunctional pro-fibrotic restorative macrophage population even after cholesterol reduction. The present work expands the understanding of the modulatory effects of cholesterol on innate immune cell transcriptome and may help identify novel therapeutic targets for NASH intervention.

Abatacept downregulates Fcγ receptor I on circulating monocytes: a potential therapeutic mechanism in patients with rheumatoid arthritis

Background

Abatacept is a recombinant fusion protein composed of the extracellular domain of cytotoxic T-lymphocyte antigen 4 and the Fc portion of immunoglobulin (Ig) G. The mechanism of action of abatacept in rheumatoid arthritis (RA) is believed to be competitive inhibition of T cell costimulation mediated by the binding of CD28 to CD80/CD86 on antigen-presenting cells, and recent studies have shown that abatacept induces reverse signaling in macrophages and osteoclast precursors in a T cell-independent manner. This study aimed to investigate the therapeutic effects of abatacept on circulating monocytes that contribute to RA pathogenesis.

Methods

Purified circulating monocytes derived from RA patients and controls were cultured in the absence or presence of abatacept or CD28-Ig for 24 h. The recovered cells were subjected to flow cytometry to evaluate the expression levels of cell surface molecules, and cytokines and chemokines in the culture supernatant were measured by multiplex bead arrays. The expression of candidate molecules was further examined by immunoblotting using total cellular extracts of the cultured monocytes. Finally, the effects of abatacept on cytokine production in monocytes stimulated with the immune complex of anti-citrullinated peptide antibodies (ACPAs) were examined.

Results

CD64/FcγRI was identified as a monocyte-derived molecule that was downregulated by abatacept but not CD28-Ig. This effect was observed in both RA patients and controls. The abatacept-induced downregulation of CD64/FcγRI was abolished by treatment with anti-CD86 antibodies but not anti-CD80 antibodies. Abatacept suppressed the production of interleukin (IL)-1β, IL-6, C-C motif chemokine ligand 2, and tumor necrosis factor-α in cultured monocytes stimulated with the ACPA immune complex.

Conclusions

The therapeutic effects of abatacept on RA are mediated, in part, by the downregulation of CD64/FcγRI on circulating monocytes via direct binding to CD86 and the suppression of immune complex-mediated inflammatory cytokine production.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13075-022-02886-8.