The human leukemia cell line, THP-1: a multifacetted model for the study of monocyte-macrophage differentiation

Extracellular Vesicles Derived From Entamoeba histolytica Have an Immunomodulatory Effect on THP-1 Macrophages

Recent studies have shown that extracellular vesicles (EVs) secreted by various parasites are capable of modulating the host's innate immune responses, such as by altering macrophage (Mϕ) phenotypes and functions. Studies have shown that Mϕ promote early host responses to amoebic infection by releasing proinflammatory cytokines that are crucial to combating amoebiasis. Here, we are reporting for the first time the effect of EVs released by Entamoeba histolytica (EhEVs) on human THP-1 differentiated Mϕ (THP-1 Mϕ). We show that the EhEVs are internalized by THP-1 Mϕ which leads to differential regulation of various cytokines associated with both M1 and M2 Mϕ. We also saw that EhEV treatment thwarted Type 2 immune-response-related transcriptome pSTAT6 in the THP-1 Mϕ. Furthermore, EhEVs stimulated Mϕ to reduce their energy demand by suppressing oxidative phosphorylation (OXPHOS) and adenosine triphosphate (ATP) production. Hence, the human parasite E. histolytica-derived EVs are capable of eliciting an immune response from Mϕ that may contribute to overall infection status.

Macrophage variants in laboratory research: most are well done, but some are RAW

Macrophages play a pivotal role in the innate immune response. While their most characteristic function is phagocytosis, it is important not to solely characterize macrophages by this activity. Their crucial roles in body development, homeostasis, repair, and immune responses against pathogens necessitate a broader understanding. Macrophages exhibit remarkable plasticity, allowing them to modify their functional characteristics in response to the tissue microenvironment (tissue type, presence of pathogens or inflammation, and specific signals from neighboring cells) swiftly. While there is no single defined "macrophage" entity, there is a diverse array of macrophage types because macrophage ontogeny involves the differentiation of progenitor cells into tissue-resident macrophages, as well as the recruitment and differentiation of circulating monocytes in response to tissue-specific cues. In addition, macrophages continuously sense and respond to environmental cues and tissue conditions, adjusting their functional and metabolic states accordingly. Consequently, it is of paramount importance to comprehend the heterogeneous origins and functions of macrophages employed in in vitro studies, as each available in vitro macrophage model is associated with specific sets of strengths and limitations. This review centers its attention on a comprehensive comparison between immortalized mouse macrophage cell lines and primary mouse macrophages. It provides a detailed analysis of the strengths and weaknesses inherent in these in vitro models. Finally, it explores the subtle distinctions between diverse macrophage cell lines, offering insights into numerous factors beyond the model type that can profoundly influence macrophage function.

NAT10/ac4C/JunB facilitates TNBC malignant progression and immunosuppression by driving glycolysis addiction

BACKGROUND

N4-Acetylcytidine (ac4C), a highly conserved post-transcriptional mechanism, plays a pivotal role in RNA modification and tumor progression. However, the molecular mechanism by which ac4C modification mediates tumor immunosuppression remains elusive in triple-negative breast cancer (TNBC).

METHODS

NAT10 expression was analyzed in TNBC samples in the level of mRNA and protein, and compared with the corresponding normal tissues. ac4C modification levels also measured in the TNBC samples. The effects of NAT10 on immune microenvironment and tumor metabolism were investigated. NAT10-mediated ac4C and its downstream regulatory mechanisms were determined in vitro and in vivo. The combination therapy of targeting NAT10 in TNBC was further explored.

RESULTS

The results revealed that the loss of NAT10 inhibited TNBC development and promoted T cell activation. Mechanistically, NAT10 upregulated JunB expression by increasing ac4C modification levels on its mRNA. Moreover, JunB further up-regulated LDHA expression and facilitated glycolysis. By deeply digging, remodelin, a NAT10 inhibitor, elevated the surface expression of CTLA-4 on T cells. The combination of remodelin and CTLA-4 mAb can further activate T cells and inhibite tumor progression.

CONCLUSION

Taken together, our study demonstrated that the NAT10-ac4C-JunB-LDHA pathway increases glycolysis levels and creates an immunosuppressive tumor microenvironment (TME). Consequently, targeting this pathway may assist in the identification of novel therapeutic strategies to improve the efficacy of cancer immunotherapy.

MCP-1 exerts the inflammatory response via ILK activation during endometriosis pathogenesis

AIMS

MCP-1 has been shown to be elevated in endometriosis. ILK functions in several cellular events and interacts with MCP-1-signaling. In the current study, we evaluated the role of MCP-1-ILK signaling in human endometriotic cell's (Hs832(C).TCs) potential for colonization, invasion, adhesion, etc. and differentiation of macrophage along with inflammation in an endometriosis mouse model.

MATERIALS AND METHODS

A mouse model of endometriosis with elevated levels of MCP-1 was developed by injecting MCP-1. We examined the migration, adhesion, colonization and invasion of Hs832(C).TCs in response to MCP-1-ILK signaling. We also examined the differentiation of THP-1 cells to macrophage in response to MCP-1-ILK signaling.

KEY FINDINGS

We observed that MCP-1 increased Ser246 phosphorylation of ILK in Hs832(C).TCs and enhanced the migration, adhesion, colonization, and invasion of Hs832(C).TCs. In the mouse model of endometriosis, we found elevated chemokines (CCL-11, CCL-22 and CXCL13) levels. An increased level of MCP-1 mediated ILK activation, leading to increased inflammatory reaction and infiltration of residential and circulatory macrophages, and monocyte differentiation, but suppressed the anti-inflammatory reaction. The inhibitor (CPD22) of ILK reversed the MCP-1-mediated action by restoring Hs832(C).TCs and THP-1 phenotype. ILK inhibition in a mouse model of endometriosis reduced the effects of MCP-1 mediated pro-inflammatory cytokines, but increased anti-inflammatory response along with T-regulatory and T-helper cell restoration.

SIGNIFICANCE

Targeting ILK restores MCP-1 milieu in the peritoneal cavity and endometrial tissues, reduces the inflammatory response, improves the T-regulatory and T-helper cells in the endometriosis mouse model and decreases the migration, adhesion, colonization and invasion of endometriotic cells.

Ligand requirements for immunoreceptor triggering

Leukocytes interact with other cells using cell surface receptors. The largest group of such receptors are non-catalytic tyrosine phosphorylated receptors (NTRs), also called immunoreceptors. NTR signalling requires phosphorylation of cytoplasmic tyrosine residues by SRC-family tyrosine kinases. How ligand binding to NTRs induces this phosphorylation, also called NTR triggering, remains controversial, with roles suggested for size-based segregation, clustering, and mechanical force. Here we exploit a recently developed cell-surface generic ligand system to explore the ligand requirements for NTR triggering. We examine the effect of varying the ligand's length, mobility and valency on the activation of representative members of four NTR families: SIRPβ1, Siglec 14, NKp44 and TREM-1. Increasing the ligand length impairs activation via NTRs, despite enhancing cell-cell conjugation, while varying ligand mobility has little effect on either conjugation or activation. Increasing the valency of the ligand, while enhancing cell-cell conjugation, does not enhance activation at equivalent levels of conjugation. These findings are more consistent with a role for size-based segregation, rather than mechanical force or clustering, in NTR triggering, suggesting a role for the kinetic-segregation model.

Optimizing Biocompatibility and Gene Delivery with DMAEA and DMAEAm: A Niacin-Derived Copolymer Approach

Gene therapy is pivotal in nanomedicine, offering a versatile approach to disease treatment. This study aims to achieve an optimal balance between biocompatibility and efficacy, which is a common challenge in the field. A copolymer library is synthesized, incorporating niacin-derived monomers 2-acrylamidoethyl nicotinate (AAEN) or 2-(acryloyloxy)ethyl nicotinate (AEN) with N,N-(dimethylamino)ethyl acrylamide (DMAEAm) or hydrolysis-labile N,N-(dimethylamino)ethyl acrylate (DMAEA). Evaluation of the polymers' cytotoxicity profiles reveals that an increase in AAEN or DMAEA molar ratios correlates with improved biocompatibility. Remarkably, an increase in AAEN in both DMAEA and DMAEAm copolymers demonstrated enhanced transfection efficiencies of plasmid DNA in HEK293T cells. Additionally, the top-performing polymers demonstrate promising gene expression in challenging-to-transfect cells (THP-1 and Jurkat cells) and show no significant effect on modulating immune response induction in ex vivo treated murine monocytes. Overall, the best performing candidates exhibit an optimal balance between biocompatibility and efficacy, showcasing potential advancements in gene therapy.

A gold nanocluster/MIL-100(Fe) bimodal nanovector for the therapy of inflammatory disease through attenuation of Toll-like receptor signaling

A better understanding of the molecular and cellular events involved in the inflammation process has opened novel perspectives in the treatment of inflammatory diseases, particularly through the development of well-designed nanomedicines. Here we describe the design of a novel class of anti-inflammatory nanomedicine (denoted as Au@MIL) synthesized through a one-pot, cost-effective and green approach by coupling a benchmark mesoporous iron(III) carboxylate metal organic framework (MOF) (i.e. MIL-100(Fe)) and glutathionate protected gold nanoclusters (i.e. Au25SG18 NCs). This nano-carrier exhibits low toxicity and excellent colloidal stability combined with the high loading capacity of the glucocorticoid dexamethasone phosphate (DexP) whose pH-dependent delivery was observed. The drug loaded Au@MIL nanocarrier shows high anti-inflammatory activity due to its capacity to specifically hinder inflammatory cell growth, scavenge intracellular reactive oxygen species (ROS) and downregulate pro-inflammatory cytokine secretion. In addition, this formulation has the capacity to inhibit the Toll-like receptor (TLR) signaling cascade namely the nuclear factor kappa B (NF-κB) and the interferon regulatory factor (IRF) pathways. This not only provides a new avenue for the nanotherapy of inflammatory diseases but also enhances our fundamental knowledge of the role of nanoMOF based nanomedicine in the regulation of innate immune signaling.

Identification of a functional missense variant in the matrix metallopeptidase 10 (MMP10) gene in two families with premature myocardial infarction

A positive family history is a major independent risk factor for atherosclerosis, and genetic variation is an important aspect of cardiovascular disease research. We identified a heterozygous missense variant p.L245P in the MMP10 gene in two families with premature myocardial infarction using whole-exome sequencing. The aim of this study was to investigate the consequences of this variant using in-silico and functional in-vitro assays. Molecular dynamics simulations were used to analyze protein interactions, calculate free binding energy, and measure the volume of the substrate-binding cleft of MMP10-TIMP1 models. The p.L245P variant showed an altered protein surface, different intra- and intermolecular interactions of MMP10-TIMP1, a lower total free binding energy between MMP10-TIMP1, and a volume-minimized substrate-binding cleft of MMP10 compared to the wild-type. For the functional assays, human THP-1 cells were transfected with plasmids containing MMP10 cDNA carrying the p.L245P and wild-type variant and differentiated into macrophages. Macrophage adhesion and migration assays were then conducted, and pro-inflammatory chemokine levels were evaluated. The p.L245P variant led to macrophages that were more adherent, less migratory, and secreted higher levels of the pro-inflammatory chemokines CXCL1 and CXCL8 than wild-type macrophages. Thus, the p.L245P variant in MMP10 may influence the pathogenesis of atherosclerosis in families with premature myocardial infarction by altering protein - protein interactions, macrophage adhesion and migration, and expression of pro-inflammatory chemokines, which may increase plaque rupture. These results could contribute to the development of selective MMP10 inhibitors and reduce the risk of atherosclerosis in families with a history of premature myocardial infarction.

Integrated Proteomics Characterization of NLRP3 Inflammasome Inhibitor MCC950 in Monocytic Cell Line Confirms Direct MCC950 Engagement with Endogenous NLRP3

Inhibition of the NLRP3 inflammasome is a promising strategy for the development of new treatments for inflammatory diseases. MCC950 is a potent and selective small-molecule inhibitor of the NLRP3 pathway and has been validated in numerous species and disease models. Although the capacity of MCC950 to block NLRP3 signaling is well-established, it is still critical to identify the mechanism of action and molecular targets of MCC950 to inform and derisk drug development. Quantitative proteomics performed in disease-relevant systems provides a powerful method to study both direct and indirect pharmacological responses to small molecules to elucidate the mechanism of action and confirm target engagement. A comprehensive target deconvolution campaign requires the use of complementary chemical biology techniques. Here we applied two orthogonal chemical biology techniques: compressed Cellular Thermal Shift Assay (CETSA) and photoaffinity labeling chemoproteomics, performed under biologically relevant conditions with LPS-primed THP-1 cells, thereby deconvoluting, for the first time, the molecular targets of MCC950 using chemical biology techniques. In-cell chemoproteomics with inlysate CETSA confirmed the suspected mechanism as the disruption of inflammasome formation via NLRP3. Further cCETSA (c indicates compressed) in live cells mapped the stabilization of NLRP3 inflammasome pathway proteins, highlighting modulation of the targeted pathway. This is the first evidence of direct MCC950 engagement with endogenous NLRP3 in a human macrophage cellular system using discovery proteomics chemical biology techniques, providing critical information for inflammasome studies.

Peptide selection via phage display to inhibit Leishmania-macrophage interactions

Introduction

Leishmaniasis comprises a complex group of diseases caused by protozoan parasites from the Leishmania genus, presenting a significant threat to human health. Infection starts by the release into the skin of metacyclic promastigote (MP) form of the parasite by an infected sand fly. Soon after their release, the MPs enter a phagocytic host cell. This study focuses on finding peptides that can inhibit MP-phagocytic host cell interaction.

Methods

We used a phage display library to screen for peptides that bind to the surface of L. amazonensis (causative agent for cutaneous leishmaniasis) and L. infantum (causative agent for cutaneous and visceral leishmaniasis) MPs. Candidate peptide binding to the MP surface and inhibition of parasite-host cell interaction were tested in vitro. Peptide Inhibition of visceral leishmaniasis development was assessed in BALB/c mice.

Results

The selected L. amazonensis binding peptide (La1) and the L. infantum binding peptide (Li1) inhibited 44% of parasite internalization into THP-1 macrophage-like cells in vitro. While inhibition of internalization by La1 was specific to L. amazonensis, Li1 was effective in inhibiting internalization of both parasite species. Importantly, Li1 inhibited L. infantum spleen and liver infection of BALB/c mice by 84%.

Conclusion

We identified one peptide that specifically inhibits L. amazonensis MP infection of host cells and another that inhibits both, L. amazonensis and L. infantum, MP infection. Our findings suggest a promising path for the development of new treatments and prevention of leishmaniasis.

AAV-mediated delivery of a Sleeping Beauty transposon and an mRNA-encoded transposase for the engineering of therapeutic immune cells

Engineering cells for adoptive therapy requires overcoming limitations in cell viability and, in the efficiency of transgene delivery, the duration of transgene expression and the stability of genomic integration. Here we report a gene-delivery system consisting of a Sleeping Beauty (SB) transposase encoded into a messenger RNA delivered by an adeno-associated virus (AAV) encoding an SB transposon that includes the desired transgene, for mediating the permanent integration of the transgene. Compared with lentiviral vectors and with the electroporation of plasmids of transposon DNA or minicircle DNA, the gene-delivery system, which we named MAJESTIC (for 'mRNA AAV-SB joint engineering of stable therapeutic immune cells'), offers prolonged transgene expression, as well as higher transgene expression, therapeutic-cell yield and cell viability. MAJESTIC can deliver chimeric antigen receptors (CARs) into T cells (which we show lead to strong anti-tumour activity in vivo) and also transduce natural killer cells, myeloid cells and induced pluripotent stem cells with bi-specific CARs, kill-switch CARs and synthetic T-cell receptors.

Degrees of macrophage-facilitated healing in aneurysm occlusion devices

Insufficient healing of aneurysms following treatment with vascular occlusion devices put patients at severe risk of fatal rupture. Therefore, promoting healing and not just occlusion is vital to enhance aneurysm healing. Following occlusion device implantation, healing is primarily orchestrated by macrophage immune cells, ending with fibroblasts depositing collagen to stabilize the aneurysm neck and dome, preventing rupture. Several modified occlusion devices are available currently on-market. Previous in vivo work demonstrated that modifications of occlusion devices with a shape memory polymer foam had enhanced aneurysm healing outcomes. To better understand cellular response to occlusion devices and improve aneurysm occlusion device design variables, we developed an in vitro assay to isolate prominent interactions between devices and key healing players: macrophages and fibroblasts. We used THP-1 monocyte derived macrophages and human dermal fibroblasts in our cell culture models. Macrophages were allowed device contact with on-market competitor aneurysm occlusion devices for up to 96 h, to allow for any spontaneous device-driven macrophage activation. Macrophage secreted factors were captured in the culture media, in response to device-specific activation. Fibroblasts were then exposed to device-conditioned macrophage media (with secreted factors alone), to determine if there were any device-induced changes in collagen secretion. Our in vitro studies were designed to test the direct effect of devices on macrophage activation, and the indirect effect of devices on collagen secretion by fibroblasts to promote aneurysm healing and stabilization. Over 96 h, macrophages displayed significant migration toward and interaction with all tested devices. As compared to other devices, shape memory polymer foams (SMM, Shape Memory Medical) induced significant changes in gene expression indicating a shift toward an anti-inflammatory pro-healing M2-like phenotype. Similarly, macrophages in contact with SMM devices secreted more vascular endothelial growth factor (VEGF) compared with other devices. Macrophage conditioned media from SMM-contacted macrophages actively promoted fibroblast secretion of collagen, comparable to amounts observed with exogenous stimulation via VEGF supplementation. Our data indicate that SMM devices may promote good aneurysm healing outcomes, because collagen production is an essential step to ultimately stabilize an aneurysm.

Characteristics of macrophage aggregates prepared by rotation culture and their response to polymeric materials

Understanding the interaction between macrophages and biomaterials is important for the creation of new biomaterials and the development of technologies to control macrophage function. Since macrophages are strongly adhesive, caution is required when performing in vitro evaluations. Similarly, when THP-1 cells, macrophage precursor cells, are differentiated into macrophages using phorbol-12-myristate-13-acetate (PMA), it becomes difficult to detach them from the adherent substrate, which has been a problem on investigation of immunological responses to biomaterials. In this study, the interaction of THP-1 cell-differentiated macrophages with biomaterials was analyzed based on a new method of seeding THP-1 cells. THP-1 cells were cultured in static and rotation culture without and with PMA. In undifferentiated THP-1 cells, there was no change in cellular function between static and rotation cultures. In rotation culture with PMA, THP-1 cells differentiated and formed macrophage aggregates. IL-1β and MRC1 expression in macrophage aggregates was examined after differentiation and M1/M2 polarization. Macrophage aggregates in rotation culture tended to be polarized toward M2 macrophages compared with those in static culture. In the evaluation of the responses of macrophage aggregates to several kinds of polymeric materials, macrophage aggregates showed different changes in MRC1 expression over time at 30, 50, and 70 rpm. Rotation speed of 30 rpm was considered most appropriate condition in that it gave stable results with the same trend as obtained with static culture. The use of macrophage aggregates obtained by rotational culture is expected to provide new insights into the evaluation of inflammatory properties of biomaterials.

Induction of TNF-α by Filifactor alocis in THP-1 macrophagic cells

OBJECTIVES

Filifactor alocis is an emerging periodontal pathogen, and macrophage-produced tumor necrosis factor-α (TNF-α) plays important roles in periodontal pathogenesis. In this study, we investigated F. alocis-stimulated TNF-α production in THP-1 macrophagic cells.

DESIGN

Phorbol 12-myristate 13-acetate-differentiated THP-1 macrophagic cells were challenged with F. alocis ATCC 35896 for various durations. TNF-α mRNA expression and protein secretion were determined using RT-PCR and ELISA, respectively. Activation of protein kinases and transcription factor proteins was evaluated by Western blot analysis.

RESULTS

Live F. alocis stimulated THP-1 cells to produce TNF-α in a dose-dependent manner. However, glutaraldehyde-killed or heat-killed F. alocis showed no effectiveness for TNF-α induction. In contrast, both live and killed Porphyromonas gingivalis robustly increased TNF-α expression. Furthermore, F. alocis was unable to stimulate TNF-α expression in Toll-like receptor 2 (TLR2) knockout THP-1 cells. F. alocis activated all three mitogen-activated protein kinases: extracellular signal-regulated kinase (ERK), p38, and c-Jun N-terminal kinase (JNK). Pharmacological inhibition of ERK and JNK, but not p38, significantly reduced F. alocis-induced TNF-α production. Finally, increased levels of phospho-c-Jun were detected in F. alocis-stimulated THP-1 cells.

CONCLUSIONS

These results suggest that F. alocis induces TNF-α production in THP-1 macrophagic cells primarily by activating the TLR2, JNK, and c-Jun pathways.

In Vivo Ultrasound Imaging of Macrophages Using Acoustic Vaporization of Internalized Superheated Nanodroplets

Activating patients' immune cells, either by reengineering them or treating them with bioactive molecules, has been a breakthrough in the field of immunotherapy and has revolutionized treatment, especially against cancer. As immune cells naturally home to tumors or injured tissues, labeling such cells holds promise for non-invasive tracking and biologic manipulation. Our study demonstrates that macrophages loaded with extremely low boiling point perfluorocarbon nanodroplets not only survive ultrasound-induced phase change but also maintain their phagocytic function. Unlike observations made when using higher boiling point perfluorocarbon nanodroplets, our results show that phase change occurs intracellularly at a low mechanical index using a clinical scanner operating within the energy limit set by the Food and Drug Administration (FDA). After nanodroplet-loaded macrophages were given intravenously to nude rats, they were invisible in the liver when imaged at a very low mechanical index using a clinical ultrasound scanner. They became visible when power was increased but still within the FDA limits up to 8 h after administration. The acoustic labeling and in vivo detection of macrophages using a clinical ultrasound scanner represent a paradigm shift in the field of cell tracking and pave the way for potential therapeutic strategies in the clinical setting.

Downregulation of DNA methylation enhances differentiation of THP-1 cells and induces M1 polarization of differentiated macrophages

DNA methylation is an epigenetic modification that regulates gene expression and plays an essential role in hematopoiesis. UHRF1 and DNMT1 are both crucial for regulating genome-wide maintenance of DNA methylation. Specifically, it is well known that hypermethylation is crucial characteristic of acute myeloid leukemia (AML). However, the mechanism underlying how DNA methylation regulates the differentiation of AML cells, including THP-1 is not fully elucidated. In this study, we report that UHRF1 or DNMT1 depletion enhances the phorbol-12-myristate-13-acetate (PMA)-induced differentiation of THP-1 cells. Transcriptome analysis and genome-wide methylation array results showed that depleting UHRF1 or DNMT1 induced changes that made THP-1 cells highly sensitive to PMA. Furthermore, knockdown of UHRF1 or DNMT1 impeded solid tumor formation in xenograft mouse model. These findings suggest that UHRF1 and DNMT1 play a pivotal role in regulating differentiation and proliferation of THP-1 cells and targeting these proteins may improve the efficiency of differentiation therapy in AML patients.

Optimization of differentiation and transcriptomic profile of THP-1 cells into macrophage by PMA

THP-1 monocyte, which can be differentiated into macrophages by PMA, is widely used in researches on pathogen infection and host innate immunity, but reports on the induction methods of PMA are different and lack a unified standard, and the transcriptome characteristics of macrophage compared with THP-1 cells remains unclear. In this research, we examined the differentiation effect of three factors including induction time, cell seeding density and PMA concentration by detecting the positive rate of CD14 expression. The concentration of 80ng/ml of PMA, the induction time of 24h, and the cell seeding density of 5×105 cells/ml, could respectively facilitates a relatively higher CD14 positive rate in THP-1 cells. Under this optimized conditions, the CD14 positive rate of THP-1 cells can reach 66.52%. Transcriptome sequencing showed that after the above induction, the mRNA expression of 3113 genes which were closely related to cell communication, signal transduction, cell response to stimulus, signaling receptor binding and cytokine activity were up-regulated, and the top 10 genes were RGS1, SPP1, GDF15, IL-1B, HAVCR2, SGK1, EGR2, TRAC, IL-8 and EBI3. While the mRNA expression of 2772 genes which were associated with cell cycle process, DNA binding and replication and cell division, were down-regulated, and the top genes were SERPINB10, TRGC2, SERPINB2, TRGC1, MS4A3, MS4A4E, TRGJP1, MS4A6A, TRGJP2, MS4A4A. This research optimized the induction method on THP-1 cell differentiation from three aspects and delineated the transcriptomic profile of PMA-induced THP-1 cells, laying a foundation for the construction method of cell model and for the functional study of macrophage.

Coupled mechanical mapping and interference contrast microscopy reveal viscoelastic and adhesion hallmarks of monocyte differentiation into macrophages

Monocytes activated by pro-inflammatory signals adhere to the vascular endothelium and migrate from the bloodstream to the tissue ultimately differentiating into macrophages. Cell mechanics and adhesion play a crucial role in macrophage functions during this inflammatory process. However, how monocytes change their adhesion and mechanical properties upon differentiation into macrophages is still not well understood. In this work, we used various tools to quantify the morphology, adhesion, and viscoelasticity of monocytes and differentiatted macrophages. Combination of atomic force microscopy (AFM) high resolution viscoelastic mapping with interference contrast microscopy (ICM) at the single-cell level revealed viscoelasticity and adhesion hallmarks during monocyte differentiation into macrophages. Quantitative holographic tomography imaging revealed a dramatic increase in cell volume and surface area during monocyte differentiation and the emergence of round and spread macrophage subpopulations. AFM viscoelastic mapping showed important stiffening (increase of the apparent Young's modulus, E₀) and solidification (decrease of cell fluidity, β) on differentiated cells that correlated with increased adhesion area. These changes were enhanced in macrophages with a spread phenotype. Remarkably, when adhesion was perturbed, differentiated macrophages remained stiffer and more solid-like than monocytes, suggesting a permanent reorganization of the cytoskeleton. We speculate that the stiffer and more solid-like microvilli and lamellipodia might help macrophages to minimize energy dissipation during mechanosensitive activities. Thus, our results revealed viscoelastic and adhesion hallmarks of monocyte differentiation that may be important for biological function.

TREM2 inhibition triggers antitumor cell activity of myeloid cells in glioblastoma

Triggering receptor expressed on myeloid cells 2 (TREM2) plays important roles in brain microglial function in neurodegenerative diseases, but the role of TREM2 in the GBM TME has not been examined. Here, we found that TREM2 is highly expressed in myeloid subsets, including macrophages and microglia in human and mouse GBM tumors and that high TREM2 expression correlates with poor prognosis in patients with GBM. TREM2 loss of function in human macrophages and mouse myeloid cells increased interferon-γ-induced immunoactivation, proinflammatory polarization, and tumoricidal capacity. In orthotopic mouse GBM models, mice with chronic and acute Trem2 loss of function exhibited decreased tumor growth and increased survival. Trem2 inhibition reprogrammed myeloid phenotypes and increased programmed cell death protein 1 (PD-1)+CD8+ T cells in the TME. Last, Trem2 deficiency enhanced the effectiveness of anti-PD-1 treatment, which may represent a therapeutic strategy for patients with GBM.

Identification of acute myeloid leukemia by infrared difference spectrum of peripheral blood

Acute myeloid leukemia (AML) is a high mortality and recurrence rates hematologic malignancy. Thus, whatever early detection or subsequent visit are both of high significance. Traditional AML diagnosis is conducted via peripheral blood (PB) smear and bone marrow (BM) aspiration. But BM aspiration is a painful burden for patients especially in early detection or subsequent visit. Herein, the use of PB to evaluate and identify the leukemia characteristics will be an attractive alternative source for early detection or subsequent visit. Fourier transform infrared spectroscopy (FTIR) is a time- and cost-effective approach to reveal the disease-related molecular features and variations. However, to the best of our knowledge, there is no attempts using infrared spectroscopic signatures of PB to replace BM for identifying AML. In this work, we are the first to develop a rapid and minimally invasive method to identify AML by infrared difference spectrum (IDS) of PB with only 6 characteristic wavenumbers. We dissect the leukemia-related spectroscopic signatures of three subtypes of leukemia cells (U937, HL-60, THP-1) by IDS, revealing biochemical molecular information about leukemia for the first time. Furthermore, the novel study links cellular features to complex features of blood system which demonstrates the sensitivity and specificity with IDS method. On this basis, BM and PB of AML patients and healthy controls were provided to parallel comparison. The IDS of BM and PB combined with principal component analysis method revealing that the leukemic components in BM and PB can be described by IDS peaks of PCA loadings, respectively. It is demonstrated that the leukemic IDS signatures of BM can be replaced by the leukemic IDS signatures of PB. In addition, the IDS signatures of leukemia cells are reflected in PB of AML patients with peaks of 1629, 1610, 1604, 1536, 1528 and 1404 cm^-1 for the first time as well. To this end, we access the leukemic signatures of IDS peaks to compare the PB of AMLs and healthy controls. It is confirmed that the leukemic components can be detected from PB of AML and distinguished into positive (100%) and negative (100%) groups successfully by IDS classifier which is a novel and unique spectral classifier. This work demonstrates the potential use of IDS as a powerful tool to detect leukemia via PB which can release subjects' pain remarkably.

Tumor-associated macrophages induce inflammation and drug resistance in a mechanically tunable engineered model of osteosarcoma

The tumor microenvironment is a complex and dynamic ecosystem composed of various physical cues and biochemical signals that facilitate cancer progression, and tumor-associated macrophages are especially of interest as a treatable target due to their diverse pro-tumorigenic functions. Engineered three-dimensional models of tumors more effectively mimic the tumor microenvironment than monolayer cultures and can serve as a platform for investigating specific aspects of tumor biology within a controlled setting. To study the combinatorial effects of tumor-associated macrophages and microenvironment mechanical properties on osteosarcoma, we co-cultured human osteosarcoma cells with macrophages within biomaterials-based bone tumor niches with tunable stiffness. In the first 24 h of direct interaction between the two cell types, macrophages induced an inflammatory environment consisting of high concentrations of tumor necrosis factor alpha (TNFα) and interleukin (IL)-6 within moderately stiff scaffolds. Expression of Yes-associated protein (YAP), but not its homolog, transcriptional activator with PDZ-binding motif (TAZ), in osteosarcoma cells was significantly higher than in macrophages, and co-culture of the two cells slightly upregulated YAP in both cells, although not to a significant degree. Resistance to doxorubicin treatment in osteosarcoma cells was correlated with inflammation in the microenvironment, and signal transducer and activator of transcription 3 (STAT3) inhibition diminished the inflammation-related differences in drug resistance but ultimately did not improve the efficacy of doxorubicin. This work highlights that the biochemical cues conferred by tumor-associated macrophages in osteosarcoma are highly variable, and signals derived from the immune system should be considered in the development and testing of novel drugs for cancer.

Fibronectin leucine-rich transmembrane protein 2 drives monocyte differentiation into macrophages via the UNC5B-Akt/mTOR axis

Upon migrating into the tissues, hematopoietic stem cell (HSC)-derived monocytes differentiate into macrophages, playing a crucial role in determining innate immune responses towards external pathogens and internal stimuli. However, the regulatory mechanisms underlying monocyte-to-macrophage differentiation remain largely unexplored. Here we divulge a previously uncharacterized but essential role for an axon guidance molecule, fibronectin leucine-rich transmembrane protein 2 (FLRT2), in monocyte-to-macrophage maturation. FLRT2 is almost undetectable in human monocytic cell lines, human peripheral blood mononuclear cells (PBMCs), and mouse primary monocytes but significantly increases in fully differentiated macrophages. Myeloid-specific deletion of FLRT2 (Flrt2ΔMyel) contributes to decreased peritoneal monocyte-to-macrophage generation in mice in vivo, accompanied by impaired macrophage functions. Gain- and loss-of-function studies support the promoting effect of FLRT2 on THP-1 cell and human PBMC differentiation into macrophages. Mechanistically, FLRT2 directly interacts with Unc-5 netrin receptor B (UNC5B) via its extracellular domain (ECD) and activates Akt/mTOR signaling. In vivo administration of mTOR agonist MYH1485 reverses the impaired phenotypes observed in Flrt2ΔMyel mice. Together, these results identify FLRT2 as a novel pivotal endogenous regulator of monocyte differentiation into macrophages. Targeting the FLRT2/UNC5B-Akt/mTOR axis may provide potential therapeutic strategies directly relevant to human diseases associated with aberrant monocyte/macrophage differentiation.

Therapeutic immune cell engineering with an mRNA : AAV- Sleeping Beauty composite system

Adoptive cell therapy has shown clinical success in patients with hematological malignancies. Immune cell engineering is critical for production, research, and development of cell therapy; however, current approaches for generation of therapeutic immune cells face various limitations. Here, we establish a composite gene delivery system for the highly efficient engineering of therapeutic immune cells. This system, termed MAJESTIC ( m RNA A AV-Sleeping-Beauty J oint E ngineering of S table T herapeutic I mmune C ells), combines the merits of mRNA, AAV vector, and transposon into one composite system. In MAJESTIC, the transient mRNA component encodes a transposase that mediates permanent genomic integration of the Sleeping Beauty (SB) transposon, which carries the gene-of-interest and is embedded within the AAV vector. This system can transduce diverse immune cell types with low cellular toxicity and achieve highly efficient and stable therapeutic cargo delivery. Compared with conventional gene delivery systems, such as lentiviral vector, DNA transposon plasmid, or minicircle electroporation, MAJESTIC shows higher cell viability, chimeric antigen receptor (CAR) transgene expression, therapeutic cell yield, as well as prolonged transgene expression. CAR-T cells generated by MAJESTIC are functional and have strong anti-tumor activity in vivo . This system also demonstrates versatility for engineering different cell therapy constructs such as canonical CAR, bi-specific CAR, kill switch CAR, and synthetic TCR; and for CAR delivery into various immune cells, including T cells, natural killer cells, myeloid cells, and induced pluripotent stem cells.

Depletion of tumor-associated macrophages inhibits lung cancer growth and enhances the antitumor effect of cisplatin

In lung cancer, tumor-associated macrophages (TAMs), especially M2-like TAMs, represent the main tumor progression components in the tumor microenvironment (TME). Therefore, M2-like TAMs may serve as a therapeutic target. The purpose of this study was to investigate the effect of M2-like TAM depletion in the TME on tumor growth and chemotherapy response in lung cancer. The levels of secreted monocyte chemoattractant protein (MCP-1) and prostaglandin E2 (PGE2) in the supernatants of lung cancer cell lines A549 and LLC were evaluated via ELISA. Cell migration assays were performed to assess the recruitment ability of macrophage cell lines THP-1 and J774-1 cells. Differentiation of macrophages was assessed via flow cytometry. Immunohistochemical staining was performed to visualize M2-like TAMs in transplanted lung cancer in mouse. We used the COX-2 inhibitor nimesulide to inhibit the secretion of MCP-1 and PGE2, which promotes macrophage migration and M2-like differentiation. Nimesulide treatment decreased the secretion of MCP-1 and PGE2 from lung cancer cells. Nimesulide treatment suppressed the migration of macrophages by blocking MCP-1. Lung cancer supernatant induced the differentiation of macrophages toward the M2-like phenotype, and nimesulide treatment inhibited M2-like differentiation by blocking MCP-1 and PGE2. In the lung cancer mouse model, treatment with nimesulide depleted M2-like TAMs in the TME and enhanced the tumor inhibitory effect of cisplatin. Our results indicated that blocking the secretion of MCP-1 and PGE2 from tumor cells depleted M2-like TAMs in the TME and the combination therapy with cisplatin considerably suppressed tumor growth in the LLC mouse model.

In vitro differentiation of myeloid suppressor cells (MDSC-like) from an immature myelomonocytic precursor THP-1

BACKGROUND

Myeloid-derived suppressor cells (MDSCs) are a heterogeneous population with a potent suppressor profile that regulates immune responses. These cells are one of the main components of the microenvironment of several diseases, including solid and hematologic tumors, autoimmunities, and chronic inflammation. However, their wide use in studies is limited due to they comprehend a rare population, which is difficult to isolate, expand, differentiate, and maintain in culture. Additionally, this population has a complex phenotypic and functional characterization.

OBJECTIVE

To develop a protocol for the in vitro production of MDSC-like population from the differentiation of the immature myeloid cell line THP-1.

METHODS

We stimulated THP-1 with G-CSF (100 ng/mL) and IL-4 (20 ng/mL) for seven days to differentiate into the MDSC-like profile. At the end of the protocol, we characterized these cells phenotypically and functionally by immunophenotyping, gene expression analysis, cytokine release dosage, lymphocyte proliferation, and NK-mediated killing essays.

RESULTS

We differentiate THP-1 cells in an MDSC-like population, named THP1-MDSC-like, which presented immunophenotyping and gene expression profiles compatible with that described in the literature. Furthermore, we verified that this phenotypic and functional differentiation did not deviate to a macrophage profile of M1 or M2. These THP1-MDSC-like cells secreted several immunoregulatory cytokines into the microenvironment, consistent with the suppressor profile related to MDSC. In addition, the supernatant of these cells decreased the proliferation of activated lymphocytes and impaired the apoptosis of leukemic cells induced by NK cells.

CONCLUSIONS

We developed an effective protocol for MDSC in vitro production from the differentiation of the immature myeloid cell line THP-1 induced by G-CSF and IL-4. Furthermore, we demonstrated that THP1-MDSC-like suppressor cells contribute to the immune escape of AML cells. Potentially, these THP1-MDSC-like cells can be applied on a large-scale platform, thus being able to impact the course of several studies and models such as cancer, immunodeficiencies, autoimmunity, and chronic inflammation.

Insights into the Safety and Versatility of 4D Printed Intravesical Drug Delivery Systems

This paper focuses on recent advancements in the development of 4D printed drug delivery systems (DDSs) for the intravesical administration of drugs. By coupling the effectiveness of local treatments with major compliance and long-lasting performance, they would represent a promising innovation for the current treatment of bladder pathologies. Being based on a shape-memory pharmaceutical-grade polyvinyl alcohol (PVA), these DDSs are manufactured in a bulky shape, can be programmed to take on a collapsed one suitable for insertion into a catheter and re-expand inside the target organ, following exposure to biological fluids at body temperature, while releasing their content. The biocompatibility of prototypes made of PVAs of different molecular weight, either uncoated or coated with Eudragit®-based formulations, was assessed by excluding relevant in vitro toxicity and inflammatory response using bladder cancer and human monocytic cell lines. Moreover, the feasibility of a novel configuration was preliminarily investigated, targeting the development of prototypes provided with inner reservoirs to be filled with different drug-containing formulations. Samples entailing two cavities, filled during the printing process, were successfully fabricated and showed, in simulated urine at body temperature, potential for controlled release, while maintaining the ability to recover about 70% of their original shape within 3 min.

Transcriptomic Analysis of Macrophage Polarization Protocols: Vitamin D3 or IL-4 and IL-13 Do Not Polarize THP-1 Monocytes into Reliable M2 Macrophages

Two main types of macrophages (Mφ) include inflammatory (M1) and anti-inflammatory (M2) macrophages. These cells can be obtained in vitro by polarization of monocytic cell lines using various stimuli. Since there is currently no consensus on the best method for the acquisition of reliable M1 and M2 macrophages from the THP-1 cell line, we decided to compare three different polarization protocols at the transcriptomic level. Whole transcriptomes of Mφ polarized according to the chosen protocols were analyzed using RNA-seq. Differential expression of genes and functional enrichment for gene ontology terms were assessed. Compared with other protocols, M1 macrophages polarized using PMA (61.3 ng/mL) and IFN-γ along with LPS had the highest expression of M1-associated regulatory genes and genes for M1 cytokines and chemokines. According to the GO enrichment analysis, genes involved in defensive and inflammatory processes were differentially expressed in these Mφ. However, all three chosen protocols which use Vit D₃, IL-13/IL-4, and IL-4, respectively, failed to promote the polarization of macrophages with a reliable M2 phenotype. Therefore, optimization or development of a new M2 polarization protocol is needed to achieve macrophages with a reliable anti-inflammatory phenotype.

Screening a small hydrazide-hydrazone combinatorial library for targeting the STAT3 in monocyte-macrophages with insulated reporter transposons

The Signal Transducer and Activator of Transcription 3 (STAT3) pharmacological targeting is regarded as a prospective approach to treat cancer, autoimmune disorders, or inflammatory diseases. We have developed a series of reporters of the STAT3, NF-κB, Nrf2, metal-responsive transcription factor-1 (MTF-1), and hypoxia-inducible factor 1α (HIF-1α) transcriptional activation in human monocyte-macrophage line THP-1. The reporter lines were employed to test a set of hydrazide-hydrazones as potential STAT3 inhibitors. A hydrazide-hydrazone library composed of 70 binary combinations of 7 carbonyl and 10 hydrazide components, including a STAT3 inhibitor clinical drug nifuroxazide, has been assembled and screened by the reporters. For the library as a whole, significant correlations between responses of the STAT3 and NF-κB or the STAT3 and HIF-1α reporters in THP-1 monocytes were found. For selected inhibitory combinations, respective hydrazide-hydrazones have been prepared and tested individually. The most potent 2-acetylpyridine 4-chlorobenzoylhydrazone exhibited the STAT3 inhibitory potential significantly exceeding that of nifuroxazide (ED50 2 vs 50 μM respectively) in THP-1 cells. We conclude that insulated reporter transposons could be a useful tool for drug discovery applications.

Graphical Abstract

The miR-106b-25 cluster mediates drug resistance in myeloid leukaemias by inactivating multiple apoptotic genes

Drug resistance is a major obstacle to the successful treatment of cancer. The role of the miR-106b-25 cluster in drug resistance of haematologic malignancies has not yet been elucidated. Here, we show that the miR-106b-25 cluster mediates resistance to therapeutic agents with structural and mechanistic dissimilarity in vitro and in vivo. RNA sequencing data revealed that overexpression of the miR-106b-25 cluster or its individual miRNAs resulted in downregulation of multiple key regulators of apoptotic pathways. Luciferase reporter assay identified TP73 as a direct target of miR-93 and miR-106b, BAK1 as a direct target of miR-25 and CASP7 as a direct target of all three miRNAs. We also showed that inhibitors of the miR-106b-25 cluster and BCL-2 exert synergistic effects on apoptosis induction in primary myeloid leukaemic cells. Thus, the members of the miR-106b-25 cluster may jointly contribute to myeloid leukaemia drug resistance by inactivating multiple apoptotic genes. Targeting this cluster could be a promising combination strategy in patients resistant to therapeutic agents that induce apoptosis.

Multi-omic integration reveals cell-type-specific regulatory networks of insulin resistance in distinct ancestry populations

Our knowledge of the cell-type-specific mechanisms of insulin resistance remains limited. To dissect the cell-type-specific molecular signatures of insulin resistance, we performed a multiscale gene network analysis of adipose and muscle tissues in African and European ancestry populations. In adipose tissues, a comparative analysis revealed ethnically conserved cell-type signatures and two adipocyte subtype-enriched modules with opposite insulin sensitivity responses. The modules enriched for adipose stem and progenitor cells as well as immune cells showed negative correlations with insulin sensitivity. In muscle tissues, the modules enriched for stem cells and fibro-adipogenic progenitors responded to insulin sensitivity oppositely. The adipocyte and muscle fiber-enriched modules shared cellular-respiration-related genes but had tissue-specific rearrangements of gene regulations in response to insulin sensitivity. Integration of the gene co-expression and causal networks further pinpointed key drivers of insulin resistance. Together, this study revealed the cell-type-specific transcriptomic networks and signaling maps underlying insulin resistance in major glucose-responsive tissues. A record of this paper's transparent peer review process is included in the supplemental information.

Remarkable Effects of a Rhenium(I)-diselenoether Drug on the Production of Cathepsins B and S by Macrophages and their Polarizations

BACKGROUND/OBJECTIVE

Tumor-associated macrophages (TAMs) produce an excessive amount of cysteine proteases, and we aimed to study the effects of anticancer rhenium(I)-diselenoether (Re-diSe) on the production of cathepsins B and S by macrophages. We investigated the effect of Re-diSe on lipopolysaccharides (LPS) induced M1 macrophages, or by interleukin 6 (IL-6) induced M2 macrophages.

METHODS

Non-stimulated or prestimulated murine Raw 264 or human THP-1 macrophages were exposed to increasing concentrations of the drug (5, 10, 20, 50 and 100 μM) and viability was assayed by the MTT assay. The amount of cysteine proteases was evaluated by ELISA tests, the number of M1 and M2 macrophages by the expression of CD80 or CD206 biomarkers. The binding of Re-diSe with GSH as a model thiol-containing protein was studied by mass spectrometry.

RESULTS

A dose-dependent decrease in cathepsins B and S was observed in M1 macrophages. There was no effect in non-stimulated cells. The drug induced a dramatic dose-dependent increase in M1 expression in both cells, significantly decreased the M2 expression in Raw 264 and had no effect in non-stimulated macrophages. The binding of the Re atom with the thiols was clearly demonstrated.

CONCLUSION

The increase in the number of M1 and a decrease in M2 macrophages treated by Re-diSe could be related to the decrease in cysteine proteases upon binding of their thiol residues with the Re atom.

Arsenic Induces M2 Macrophage Polarization and Shifts M1/M2 Cytokine Production via Mitophagy

Arsenic is an environmental factor associated with epithelial-mesenchymal transition (EMT). Since macrophages play a crucial role in regulating EMT, we studied the effects of arsenic on macrophage polarization. We first determined the arsenic concentrations to be used by cell viability assays in conjunction with previous studies. In our results, arsenic treatment increased the alternatively activated (M2) macrophage markers, including arginase 1 (ARG-1) gene expression, chemokine (C-C motif) ligand 16 (CCL16), transforming growth factor-β1 (TGF-β1), and the cluster of differentiation 206 (CD206) surface marker. Arsenic-treated macrophages promoted A549 lung epithelial cell invasion and migration in a cell co-culture model and a 3D gel cell co-culture model, confirming that arsenic treatment promoted EMT in lung epithelial cells. We confirmed that arsenic induced autophagy/mitophagy by microtubule-associated protein 1 light-chain 3-II (LC3 II) and phosphor-Parkin (p-Parkin) protein markers. The autophagy inhibitor chloroquine (CQ) recovered the expression of the inducible nitric oxide synthase (iNOS) gene in arsenic-treated M1 macrophages, which represents a confirmation that arsenic indeed induced the repolarization of classically activated (M1) macrophage to M2 macrophages through the autophagy/mitophagy pathway. Next, we verified that arsenic increased M2 cell markers in mouse blood and lungs. This study suggests that mitophagy is involved in the arsenic-induced M1 macrophage switch to an M2-like phenotype.

Altered recruitment of Sp isoforms to HIV-1 long terminal repeat between differentiated monoblastic cell lines and primary monocyte-derived macrophages

Human immunodeficiency virus type 1 (HIV-1) transcription in cells of the monocyte-macrophage lineage is regulated by interactions between the HIV-1 long terminal repeat (LTR) and a variety of host cell and viral proteins. Binding of the Sp family of transcription factors (TFs) to the G/C box array of the LTR governs both basal as well as activated LTR-directed transcriptional activity. The effect of monocytic differentiation on Sp factor binding and transactivation was examined with respect to the HIV-1 LTR. The binding of Sp1, full-length Sp3 and truncated Sp3 to a high affinity HIV-1 Sp element was specifically investigated and results showed that Sp1 binding increased relative to the binding of the sum of full-length and truncated Sp3 binding following chemically-induced monocytic differentiation in monoblastic (U-937, THP-1) and myelomonocytic (HL-60) cells. In addition, Sp binding ratios from PMA-induced cell lines were shown to more closely approximate those derived from primary monocyte-derived macrophages (MDMs) than did ratios derived from uninduced cell lines. The altered Sp binding phenotype associated with changes in the transcriptional activation mediated by the HIV-1 G/C box array. Additionally, analysis of post-translational modifications on Sp1 and Sp3 revealed a loss of phosphorylation on serine and threonine residues with chemically-induced differentiation indicating that the activity of Sp factors is additionally regulated at the level of post-translational modifications (PTMs).

Lacticaseibacillus casei Strain Shirota Modulates Macrophage-Intestinal Epithelial Cell Co-Culture Barrier Integrity, Bacterial Sensing and Inflammatory Cytokines

Probiotic bacteria modulate macrophage immune inflammatory responses, with functional cytokine responses determined by macrophage subset polarisation, stimulation and probiotic strain. Mucosal macrophages exhibit subset functional heterogeneity but are organised in a 3-dimensional tissue, over-laid by barrier epithelial cells. This study aimed to investigate the effects of the probiotic Lacticaseibacillus casei strain Shirota (LcS) on macrophage-epithelial cell cytokine responses, pattern recognition receptor (PRR) expression and LPS responses and the impacts on barrier integrity. THP-1-derived M1 and M2 subset macrophages were co-cultured in a transwell system with differentiated Caco-2 epithelial cells in the presence or absence of enteropathogenic LPS. Both Caco-2 cells in monoculture and macrophage co-culture were assayed for cytokines, PRR expression and barrier integrity (TEER and ZO-1) by RT-PCR, ELISA, IHC and electrical resistance. Caco-2 monocultures expressed distinct cytokine profiles (IL-6, IL-8, TNFα, endogenous IL-10), PRRs and barrier integrity, determined by inflammatory context (TNFα or IL-1β). In co-culture, LcS rescued ZO-1 and TEER in M2/Caco-2, but not M1/Caco-2. LcS suppressed TLR2, TLR4, MD2 expression in both co-cultures and differentially regulated NOD2, TLR9, Tollip and cytokine secretion. In conclusion, LcS selectively modulates epithelial barrier integrity, pathogen sensing and inflammatory cytokine profile; determined by macrophage subset and activation status.

Muramyl dipeptide-based analogs as potential anticancer compounds: Strategies to improve selectivity, biocompatibility, and efficiency

According to the WHO, cancer is the second leading cause of death in the world. This is an important global problem and a major challenge for researchers who have been trying to find an effective anticancer therapy. A large number of newly discovered compounds do not exert selective cytotoxic activity against tumorigenic cells and have too many side effects. Therefore, research on muramyl dipeptide (MDP) analogs has attracted interest due to the urgency for finding more efficient and safe treatments for oncological patients. MDP is a ligand of the cytosolic nucleotide-binding oligomerization domain 2 receptor (NOD2). This molecule is basic structural unit that is responsible for the immune activity of peptidoglycans and exhibits many features that are important for modern medicine. NOD2 is a component of the innate immune system and represents a promising target for enhancing the innate immune response as well as the immune response against cancer cells. For this reason, MDP and its analogs have been widely used for many years not only in the treatment of immunodeficiency diseases but also as adjuvants to support improved vaccine delivery, including for cancer treatment. Unfortunately, in most cases, both the MDP molecule and its synthesized analogs prove to be too pyrogenic and cause serious side effects during their use, which consequently exclude them from direct clinical application. Therefore, intensive research is underway to find analogs of the MDP molecule that will have better biocompatibility and greater effectiveness as anticancer agents and for adjuvant therapy. In this paper, we review the MDP analogs discovered in the last 10 years that show promise for antitumor therapy. The first part of the paper compiles the achievements in the field of anticancer vaccine adjuvant research, which is followed by a description of MDP analogs that exhibit promising anticancer and antiproliferative activity and their structural changes compared to the original MDP molecule.

Extracts Prepared from Feed Supplements Containing Wood Lignans Improve Intestinal Health by Strengthening Barrier Integrity and Reducing Inflammation

Lignans are known to exhibit a broad spectrum of biological activities, indicating their potential as constituents of feed supplements. This study investigated two extracts derived from the feed supplements ‘ROI’ and ‘Protect’—which contain the wood lignans magnolol and honokiol (‘ROI’), or soluble tannins additional to the aforementioned lignans (‘Protect’)—and their impact on selected parameters of intestinal functionality. The antioxidant and anti-inflammatory properties of the extracts were determined by measuring their effects on reactive oxygen species (ROS) and pro-inflammatory cytokine production in vitro. The impact on intestinal barrier integrity was evaluated in Caco-2 cells and Drosophila melanogaster by examining leaky gut formation. Furthermore, a feeding trial using infected piglets was conducted to study the impact on the levels of superoxide dismutase, glutathione and lipid peroxidation. The Protect extract lowered ROS production in Caco-2 cells and reversed the stress-induced weakening of barrier integrity. The ROI extract inhibited the expression or secretion of interleukin-8 (IL-8), interleukin-6 (IL-6), interleukin-1β (IL-1β) and tumor necrosis factor α (TNFα). Moreover, the ROI extract decreased leaky gut formation and mortality rates in Drosophila melanogaster. Dietary supplementation with Protect improved the antioxidant status and barrier integrity of the intestines of infected piglets. In conclusion, wood lignan-enriched feed supplements are valuable tools that support intestinal health by exerting antioxidant, anti-inflammatory and barrier-strengthening effects.

Lunasin as a Promising Plant-Derived Peptide for Cancer Therapy

Cancer has become one of the main public health problems worldwide, demanding the development of new therapeutic agents that can help reduce mortality. Lunasin is a soybean peptide that has emerged as an attractive option because its preventive and therapeutic actions against cancer. In this review, we evaluated available research on lunasin’s structure and mechanism of action, which should be useful for the development of lunasin-based therapeutic products. We described data on its primary, secondary, tertiary, and possible quaternary structure, susceptibility to post-translational modifications, and structural stability. These characteristics are important for understanding drug activity and characterizing lunasin products. We also provided an overview of research on lunasin pharmacokinetics and safety. Studies examining lunasin’s mechanisms of action against cancer were reviewed, highlighting reported activities, and known molecular partners. Finally, we briefly discussed commercially available lunasin products and potential combination therapeutics.

Dexamethasone Sensitizes Acute Monocytic Leukemia Cells to Ara-C by Upregulating FKBP51

In this study, we demonstrated that the expression of FK506 binding protein 51 (FKBP51) is upregulated in acute monocytic leukemia (AML-M5) cells by dexamethasone and aimed to investigate the possible effects of FKBP51 on the growth and cytarabine sensitivity of AML-M5 cells. THP-1 and U937cells were used to establish AML-M5 cell models with FKBP51 overexpression and knockdown, respectively. Cell proliferation, apoptosis and response to cytarabine were investigated by cell cycle, CCK-8 and Flow cytometry analyses. The mice experiment was conducted to detect the role of FKBP51 on AML-M5 cells proliferation and antileukemia effect of Ara-C/Dexamethasone co-therapy in vivo. Western blots were employed to determine protein expression levels. FKBP51 upregulation significantly attenuated THP-1 cell proliferation and sensitized the cells to cytarabine treatment which was further enhanced by dexamethasone. These effects were indicated by decreases in cell viability, S-G2/M phase cell cycle distribution, cytarabine 50% inhibitory concentration (IC50) values and increases in apoptosis and were supported by decreased phosphorylation levels of AKT, GSK3β and FOXO1A and decreased levels of BCL-2 and increased levels of P21 and P27. In contrast, FKBP51 knockdown led to excessive U937 cell proliferation and cytarabine resistance, as indicated by increased cell viability and S-G2/M phase cell cycle distribution, decreased apoptosis, increased phosphorylation levels of AKT, GSK3β and FOXO1A, and increased BCL-2 and decreased P21 and P27 expression. In addition, an AKT inhibitor blocked cell cycle progression and reduced cell viability in all groups of cells. Furthermore, SAFit2, a specific FKBP51 inhibitor, increased U937 cell viability and cytarabine resistance as well as AKT phosphorylation. In conclusion, FKBP51 decelerates proliferation and improves the cytarabine sensitivity of AML-M5 cells by inhibiting AKT pathways, and dexamethasone in combination with Ara-C improves the chemosensitivity of AML-M5.

Resveratrol and ω-3 PUFAs Promote Human Macrophage Differentiation and Function

Monocytes differentiate into M1 and M2 macrophages, which are classically activated by microbial products such as LPS or IFN-γ and interleukins (e.g., the anti-inflammatory and T_h2 promoting IL-4), respectively. The contribution of nutrients or nutrient-based substances such as ω-3 polyunsaturated fatty acids (ω-3 PUFAs) and resveratrol (Res) on the differentiation and function of M1 and M2 macrophages was evaluated. THP-1 cells and peripheral blood mononuclear cells (PBMCs) were differentiated into M1 and M2 cells and activated with LPS/IFN-γ or IL-4/IL-13. Macrophage lineage specific surface determinants (e.g., CD11b, CD11c, CD14, CD206, CD209, CD274, HLA-DR, CCR7, CCR2) were analysed by cytofluorometry. Res and ω-3 PUFAs altered CD14, CD206, CD274 and HL-DR surface expression patterns in M1 and M2 macrophages differentiated from PBMC. LPS/IFN-γ or IL-14/IL-13 activated macrophages subpopulations, which secreted cytokines and chemokines as measured by multiplex ELISA. Res and ω-3 PUFA reduced IL-1β, IL-6, TNF-α, CXCL10/IP-10, CCL13/MCP-4 and CCL20/MIP-3α in LPS/IFN-γ activated human leukaemia THP-1 cells, which is indicative of a dampening effect on M1 macrophages. However, Res increased M1 prototypic cytokines such as IL-1β or IL-6 in macrophages derived from PBMCs and also modified the expression of IL-12p70. Collectively, Res and ω-3 PUFAs distinctly promoted the differentiation and function of M1 and M2 macrophages. We conclude that these substances strengthen the macrophage-mediated effects on the innate and adaptive immune response.

High-resolution crystal structure of LpqH, an immunomodulatory surface lipoprotein of Mycobacterium tuberculosis reveals a distinct fold and a conserved cleft on its surface

Tuberculosis, caused by Mycobacterium tuberculosis, is predominantly a disease of the lungs acquired by inhaling mycobacteria from infected individuals via airborne droplets. In order to facilitate their entry into the alveolar macrophages, mycobacteria have a collection of pathogen-associated molecular patterns (PAMPs) on their surface that are known to detect certain pattern recognition receptors present on the surface of host cells. A major group of these PAMPs includes mycobacterial lipoproteins, of which, the 19 kDa surface antigen LpqH, has been reported to play a critical role in both host-pathogen interactions as well as pleiotropic immune regulation. Despite its crucial involvement in tuberculosis, the detailed structure-function relationship of this protein remains to be explored. Here, we report the high-resolution crystal structure of the non-acylated LpqH (LpqH^48-159) at a resolution of 1.26 Å, which adopts a unique fold. Flow cytometry-based experiments show that the protein can bind and induce apoptosis in PMA-activated human monocytic cell line THP-1, indicative of the preservation of functionality of the protein. Furthermore, analysis of conservation of LpqH sequences from Mycobacterium species reveals a patch of conserved residues on the surface which may play a role in its binding partner recognition and hence in host-pathogen interaction.

Exosomal circRNA BTG2 derived from RBP-J overexpressed-macrophages inhibits glioma progression via miR-25-3p/PTEN

Macrophage-derived exosomes (Mφ-Exos) are involved in tumor progression, but its role in glioma is not fully understood. RBP-J is related to macrophage activation. In this study, we assess the role of exosomes derived from RBP-J-overexpressed macrophages (RBP-J OE Mφ-Exos) in glioma. The circular RNA (circRNA) profiles in RBP-J OE Mφ-Exos and THP-1-like macrophages (WT Mφ)-Exos were evaluated using circRNA microarray. Then the functions of Mφ-Exo-circRNA in glioma cells were assessed via CCK-8, EdU, Transwell invasion, and nude mouse assays. Besides, luciferase reporter assay, RNA immunoprecipitation, and Pearson's correlation analysis were adopted to confirm interactions. We found that circRNA BTG (circBTG2) is upregulated in RBP-J OE Mφ-Exos compared to WT Mφ-Exos. RBP-J OE Mφ-Exos co-culture and circBTG2 overexpression inhibited proliferation and invasion of glioma cells, whereas circBTG2 knockdown promotes tumor growth in vivo. The effects of RBP-J OE Mφ-Exos on glioma cells can be reversed by the circBTG2 knockdown. In conclusions, Exo-circBTG2 secreted from RBP-J OE Mφ inhibits tumor progression through the circBTG2/miR-25-3p/PTEN pathway, and circBTG2 is probably a diagnostic biomarker and potential target for glioma therapy.

Understanding the Link between Inflammasome and Apoptosis through the Response of THP-1 Cells against Drugs Using Droplet-Based Microfluidics

Droplet-based microfluidic devices are used to investigate monocytic THP-1 cells in response to drug administration. Consistent and reproducible droplets are created, each of which acts as a bioreactor to carry out single cell experiments with minimized contamination and live cell tracking under an inverted fluorescence microscope for more than 2 days. Here, the effects of three different drugs (temsirolimus, rifabutin, and BAY 11-7082) on THP-1 are examined and the results are analyzed in the context of the inflammasome and apoptosis relationship. The ASC adaptor gene tagged with GFP is monitored as the inflammasome reporter. Thus, a systematic way is presented for deciphering cell-to-cell heterogeneity, which is an important issue in cancer treatment. The drug temsirolimus, which has effects of disrupting the mTOR pathway and triggering apoptosis in tumor cells, causes THP-1 cells to express ASC and to be involved in apoptosis. Treatment with rifabutin, which inhibits proliferation and initiates apoptosis in cells, affects ASC expression by first increasing and then decreasing it. CASP-3, which has a role in apoptosis and is directly related to ASC, has an increasing level in inflammasome conditioning. Thus, the cell under the effect of rifabutin might be faced with programmed cell death faster. The drug BAY 11-7082, which is responsible for NFκB inhibition, shows similar results to temsirolimus with more than 60% of cells having high fluorescence intensity (ASC expression). The microfluidic platform presented here offers strong potential for studying newly developed small-molecule inhibitors for personalized/precision medicine.

Harmonic acoustics for dynamic and selective particle manipulation

Precise and selective manipulation of colloids and biological cells has long been motivated by applications in materials science, physics and the life sciences. Here we introduce our harmonic acoustics for a non-contact, dynamic, selective (HANDS) particle manipulation platform, which enables the reversible assembly of colloidal crystals or cells via the modulation of acoustic trapping positions with subwavelength resolution. We compose Fourier-synthesized harmonic waves to create soft acoustic lattices and colloidal crystals without using surface treatment or modifying their material properties. We have achieved active control of the lattice constant to dynamically modulate the interparticle distance in a high-throughput (>100 pairs), precise, selective and reversible manner. Furthermore, we apply this HANDS platform to quantify the intercellular adhesion forces among various cancer cell lines. Our biocompatible HANDS platform provides a highly versatile particle manipulation method that can handle soft matter and measure the interaction forces between living cells with high sensitivity.

Porphyromonas gingivalis Gingipains Induce Cyclooxygenase-2 Expression and Prostaglandin E2 Production via ERK1/2-Activated AP-1 (c-Jun/c-Fos) and IKK/NF-κB p65 Cascades

Porphyromonas gingivalis is commonly known as one of the major pathogens contributing to periodontitis, and its persistent infection may increase the risk for the disease. The proinflammatory mediators, including IL-6, TNF-α, and cyclooxygenase-2 (COX-2)/PGE₂, are closely associated with progression of periodontitis. In this study, we focused on the cysteine protease "gingipains," lysine-specific gingipain, arginine-specific gingipain (Rgp) A, and RgpB, produced by P. gingivalis, and used the wild-type strain and several gene-deletion mutants (rgpA, rgpB, kgp, and fimA) to elucidate the involvement of gingipains in COX-2 expression and PGE₂ production. We infected human monocytes, which are THP-1 cells and primary monocytes, with these bacterial strains and found that gingipains were involved in induction of COX-2 expression and PGE₂ production. We have shown that the protease activity of gingipains was crucial for these events by using gingipain inhibitors. Furthermore, activation of ERK1/2 and IκB kinase was required for gingipain-induced COX-2 expression/PGE₂ production, and these kinases activated two transcription factors, c-Jun/c-Fos (AP-1) and NF-κB p65, respectively. In particular, these data suggest that gingipain-induced c-Fos expression via ERK is essential for AP-1 formation with c-Jun, and activation of AP-1 and NF-κB p65 plays a central role in COX-2 expression/PGE₂ production. Thus, we show the (to our knowledge) novel finding that gingipains with the protease activity from P. gingivalis induce COX-2 expression and PGE₂ production via activation of MEK/ERK/AP-1 and IκB kinase/NF-κB p65 in human monocytes. Hence it is likely that gingipains closely contribute to the inflammation of periodontal tissues.

Cordycerebroside A inhibits ICAM-1-dependent M1 monocyte adhesion to osteoarthritis synovial fibroblasts

Osteoarthritis (OA) is represented by the accumulation and adhesion of M1 macrophages into synovium tissues in the joint microenvironment and subsequent inflammatory response. Cordycerebroside A, a cerebroside compound isolated from Cordyceps militaris, exhibits anti-inflammatory activity, but has not yet been examined in M1 macrophages during OA disease. Our results indicate higher expression of M1 macrophage markers in synovium tissue from OA patients compared with normal healthy controls. Records from the Gene Expression Omnibus (GEO) data set and our clinic samples revealed higher levels of ICAM-1 (a critical adhesion molecule during OA disease) and CD86 (a M1 macrophage marker) in OA synovial tissue than in healthy tissue. The same effects were found in rats with OA induced by anterior cruciate ligament transaction (ACLT). We also found that cordycerebroside A inhibited ICAM-1 synthesis and antagonized M1 macrophage adhesion to OA synovial fibroblasts by inhibiting the ERK/AP-1 pathway. Thus, cordycerebroside A displayed novel anti-arthritic effects. PRACTICAL APPLICATIONS: Here we report a higher level of M1 macrophage markers and ICAM-1 in synovium tissue from OA patients compared with normal healthy controls by using GEO data set and our clinic samples. The same effects were revealed in rats with OA induced by ACLT. Cordycerebroside A significantly suppressed ICAM-1 production and diminished M1 macrophage adhesion to OA synovial fibroblasts. Therefore, cordycerebroside A exhibited novel anti-OA functions.

Peripheral blood monocytes predict clinical prognosis and support tumor invasiveness through NF-κB-dependent upregulation of Snail in pancreatic cancer

Background

The tumor inflammatory microenvironment plays a vital role in the initiation and progression of pancreatic cancer (PC). Both the lymphocyte-to-monocyte ratio (LMR) and preoperative peripheral blood monocytes are related to the prognosis of PC patients. However, the direct effect of monocytes on PC cells is not fully understood. The current study aimed to assess the effect of monocytes on PC and explore its potential mechanism.

Methods

The cutoff value of peripheral blood monocytes was evaluated by the receiver operating characteristic (ROC) curve. Transwell migration and invasion assays were used to detect the mobility of PC cells. The cytokines derived from monocytes were measured by quantitative real-time polymerase chain reaction (qRT-PCR). Western blotting was utilized to assess the expression of epithelial-mesenchymal transition (EMT) related markers. The expression level of Snail in PC tissue was determined by immunohistochemical (IHC) staining.

Results

A high monocyte count was inversely correlated with lymph node status and 5-year overall survival in PC. The PC cells underwent a cellular morphology change and increased cell motility after coculture with THP-1 monocytes. The THP-1 monocytes secreted various proinflammatory cytokines, including tumor necrosis factor-α (TNF-α) and interleukin-1α (IL-1α), which activated the nuclear factor-κB (NF-κB) signaling pathway leading to the upregulation of Snail and thereby promoting the EMT of PC cells. The expression level of Snail correlated significantly with the density of peripheral blood monocytes, and their level status was significantly associated with 5-year overall survival.

Conclusions

These findings indicated that elevated monocytes counts were a poor prognostic marker in PC, and monocytes could directly induce the EMT process of PC cells by upregulating Snail expression through the NF-κB signaling pathway.

In Vitro Methodologies to Study the Role of Advanced Glycation End Products (AGEs) in Neurodegeneration

Advanced glycation end products (AGEs) can be present in food or be endogenously produced in biological systems. Their formation has been associated with chronic neurodegenerative diseases such as Alzheimer’s disease, Parkinson’s disease, multiple sclerosis, and amyotrophic lateral sclerosis. The implication of AGEs in neurodegeneration is related to their ability to bind to AGE-specific receptors and the ability of their precursors to induce the so-called “dicarbonyl stress”, resulting in cross-linking and protein damage. However, the mode of action underlying their role in neurodegeneration remains unclear. While some research has been carried out in observational clinical studies, further in vitro studies may help elucidate these underlying modes of action. This review presents and discusses in vitro methodologies used in research on the potential role of AGEs in neuroinflammation and neurodegeneration. The overview reveals the main concepts linking AGEs to neurodegeneration, the current findings, and the available and advisable in vitro models to study their role. Moreover, the major questions regarding the role of AGEs in neurodegenerative diseases and the challenges and discrepancies in the research field are discussed.

New Strategies to Promote Macrophage Cholesterol Efflux

The capacity of macrophages to dispose of cholesterol deposited in the atherosclerotic plaque depends on their ability to activate cholesterol efflux pathways. To develop athero-protective therapies aimed at promoting macrophage cholesterol efflux, cholesterol metabolism in THP-1 monocyte-derived macrophages has been extensively studied, but the intrinsic sensitivity of monocytes and the lack of a standardized procedure to differentiate THP-1 monocytes into macrophages have made it difficult to utilize THP-1 macrophages in the same or similar degree of differentiation across studies. The variability has resulted in lack of understanding of how the differentiation affects cholesterol metabolism, and here we review and investigate the effects of THP-1 differentiation on cholesterol efflux. The degree of THP-1 differentiation was inversely associated with ATP binding cassette A1 (ABCA1) transporter-mediated cholesterol efflux. The differentiation-associated decrease in ABCA1-mediated cholesterol efflux occurred despite an increase in ABCA1 expression. In contrast, DSC1 expression decreased during the differentiation. DSC1 is a negative regulator of the ABCA1-mediated efflux pathway and a DSC1-targeting agent, docetaxel showed high potency and efficacy in promoting ABCA1-mediated cholesterol efflux in THP-1 macrophages. These data suggest that pharmacological targeting of DSC1 may be more effective than increasing ABCA1 expression in promoting macrophage cholesterol efflux. In summary, the comparison of THP-1 macrophage subtypes in varying degrees of differentiation provided new insights into cholesterol metabolism in macrophages and allowed us to identify a viable target DSC1 for the promotion of cholesterol efflux in differentiated macrophages. Docetaxel and other pharmacological strategies targeting DSC1 may hold significant potential for reducing atherogenic cholesterol deposition.

Exosomal hsa_circ_0004658 derived from RBPJ overexpressed-macrophages inhibits hepatocellular carcinoma progression via miR-499b-5p/JAM3

Macrophage-derived exosomes (Mφ-Exo) have multidimensional involvement in tumor initiation, progression, and metastasis, but their regulation in hepatocellular carcinoma (HCC) is not fully understood. RBPJ has been implicated in macrophage activation and plasticity. In this study we assess the role of exosomes derived from RBPJ-overexpressed macrophages (RBPJ^+/+ Mφ-Exo) in HCC. The circular RNA (circRNA) profiles in RBPJ^+/+ Mφ-Exo and THP-1-like macrophages (WT Mφ)-Exo was evaluated using circRNA microarray. CCK-8, Transwell, and flow cytometry analyses were used to evaluate the function of Mφ-Exo-circRNA on HCC cells. Luciferase reporter assays, RNA immunoprecipitation, and Pearson’s correlation analysis were used to confirm interactions. A nude mouse xenograft model was used to further analyze the functional significance of Mφ-Exo-cirRNA in vivo. Our results shown that hsa_circ_0004658 is upregulated in RBPJ^+/+ Mφ-Exo compared to WT Mφ-Exo. RBPJ^+/+ Mφ-Exo and hsa_circ_0004658 inhibits proliferation and promotes apoptosis in HCC cells, whereas hsa_circ_0004658 knockdown stimulated cell proliferation and migration but restrained apoptosis in vitro and promotes tumor growth in vivo. The effects of RBPJ^+/+ Mφ-Exo on HCC cells can be reversed by the hsa_circ_0004658 knockdown. Mechanistic investigations revealed that hsa_circ_0004658 acts as a ceRNA of miR-499b-5p, resulting in the de-repression of JAM3. These results indicate that exosome circRNAs secreted from RBPJ^+/+ Mφ inhibits tumor progression through the hsa_circ_0004658/miR-499b-5p/JAM3 pathway and hsa_circ_0004658 may be a diagnostic biomarker and potential target for HCC therapy.