Control of pro-inflammatory cytokine release from human monocytes with the use of an interleukin-10 monoclonal antibody

TIMEPOINT, a phase 1 study combining MTL-CEBPA with pembrolizumab, supports the immunomodulatory effect of MTL-CEBPA in solid tumors

Many patients with cancer do not benefit from currently approved immune checkpoint inhibitors (ICIs), suggesting that additional immunomodulation of the immunosuppressive tumor microenvironment (TME) is required. MTL-CCAAT enhancer-binding protein alpha (CEBPA) specifically upregulates the expression of the master myeloid transcription factor, CEBPA, relieving myeloid-driven immunosuppression. Here, we report the safety, tolerability, pharmacokinetics, and efficacy of MTL-CEBPA in combination with pembrolizumab in patients with advanced solid tumors that typically show ICI resistance. Multimodal exploratory analyses of paired patient biopsies demonstrate biological changes associated with the combination treatment of MTL-CEBPA and pembrolizumab, including increased infiltration of T cell and antigen-presenting cells supporting conversion from an immune-desert toward a more immune-inflamed TME. Patients with disease stabilization demonstrate reductions in immunosuppressive myeloid cells post treatment. Collectively, these data support a role for MTL-CEBPA in reducing immunosuppression in the TME. This study was registered at ClinicalTrials.gov (NCT04105335).

Oral Excretion Kinetics of Food-Additive Silicon Dioxides and Their Effect on In Vivo Macrophage Activation

A food additive, silicon dioxide (SiO2) is commonly used in the food industry as an anti-caking agent. The presence of nanoparticles (NPs) in commercial food-grade SiO2 has raised concerns regarding their potential toxicity related to nano size. While recent studies have demonstrated the oral absorption and tissue distribution of food-additive SiO2 particles, limited information is available about their excretion behaviors and potential impact on macrophage activation. In this study, the excretion kinetics of two differently manufactured (fumed and precipitated) SiO2 particles were evaluated following repeated oral administration to rats for 28 d. The excretion fate of their intact particles, decomposed forms, or ionic forms was investigated in feces and urine, respectively. Monocyte uptake, Kupffer cell activation, and cytokine release were assessed after the oral administration of SiO2 particles. Additionally, their intracellular fates were determined in Raw 264.7 cells. The results revealed that the majority of SiO2 particles were not absorbed but directly excreted via feces in intact particle forms. Only a small portion of SiO2 was eliminated via urine, predominantly in the form of bioconverted silicic acid and slightly decomposed ionic forms. SiO2 particles were mainly present in particle forms inside cells, followed by ionic and silicic acid forms, indicating their slow conversion into silicic acid after cellular uptake. No effects of the manufacturing method were observed on excretion and fates. Moreover, no in vivo monocyte uptake, Kupffer cell polarization, or cytokine release were induced by orally administered SiO2 particles. These finding contribute to understanding the oral toxicokinetics of food-additive SiO2 and provide valuable insights into its potential toxicity.

Phenotypic and Functional Heterogeneity of Monocyte Subsets in Chronic Heart Failure Patients

Chronic heart failure (CHF) results when the heart cannot consistently supply the body's tissues with oxygen and required nutrients. CHF can be categorized as heart failure (HF) with preserved ejection fraction (HFpEF) or HF with reduced ejection fraction (HFrEF). There are different causes and mechanisms underlying HF pathogenesis; however, inflammation can be regarded as one of the factors that promotes both HFrEF and HFpEF. Monocytes, a subgroup of leukocytes, are known to be cellular mediators in response to cardiovascular injury and are closely related to inflammatory reactions. These cells are a vital component of the immune system and are the source of macrophages, which participate in cardiac tissue repair after injury. However, these monocytes are not as homogenous as thought and can present different functions under different cardiovascular disease conditions. In addition, there is still an open question regarding whether the functions of monocytes and macrophages should be regarded as causes or consequences in CHF development. Therefore, the aim of this work was to summarize current studies on the functions of various monocyte subsets in CHF with a focus on the role of a certain monocyte subset in HFpEF and HFrEF patients, as well as the subsets' relationship to inflammatory markers.

Analysis of the impact of corticosteroids adjuvant treatment during experimental invasive meningococcal infection in mice

Invasive meningococcal disease (IMD) is usually associated with intense inflammatory response that is correlated with severe infection. Corticosteroids may regulate this inflammatory response through an early but transient induction of IL-10 that is suggested to improve the outcome of IMD. We explored the mechanism of action of corticosteroids as an adjuvant treatment to antibiotics. Transgenic mice expressing the human transferrin were infected by a hyperinvasive meningococcal strain and transcriptomic analysis were then performed in the blood for all conditions of infection and treatment. Infected untreated mice, infected antibiotic-treated mice and infected amoxicillin and dexamethasone-treated mice were compared. Treatment using both corticosteroids and antibiotics was associated with differential gene expression in the blood especially in Monocytes-Macrophages pathways. Depletion of these cells in infected mice was associated with a more severe bacterial infection and uncontrolled production of both pro-inflammatory and anti-inflammatory cytokines. Accordingly, children suffering from severe IMD had low counts of monocytes at admission. Our data are in favor of a role of corticosteroids in enhancing a polarization from pro-inflammatory to anti-inflammatory phenotypes of Monocytes-Macrophages axis that may help controlling meningococcal invasive infections.