Establishment and characterization of a human acute monocytic leukemia cell line (THP-1)

Anti-C1s humanized monoclonal antibody SAR445088: A classical pathway complement inhibitor specific for the active form of C1s

The objective of this study was to characterize the complement-inhibiting activity of SAR445088, a novel monoclonal antibody specific for the active form of C1s. Wieslab® and hemolytic assays were used to demonstrate that SAR445088 is a potent, selective inhibitor of the classical pathway of complement. Specificity for the active form of C1s was confirmed in a ligand binding assay. Finally, TNT010 (a precursor to SAR445088) was assessed in vitro for its ability to inhibit complement activation associated with cold agglutinin disease (CAD). TNT010 inhibited C3b/iC3b deposition on human red blood cells incubated with CAD patient serum and decreased their subsequent phagocytosis by THP-1 cells. In summary, this study identifies SAR445088 as a potential therapeutic for the treatment of classical pathway-driven diseases and supports its continued assessment in clinical trials.

mTORC1/ERK1/2 Interplay Regulates Protein Synthesis and Survival in Acute Myeloid Leukemia Cell Lines

mTOR is constitutively activated in acute myeloid leukemia (AML) cells, as indicated by the phosphorylation of its substrates, 4EBP1 and P70S6K. Here, we found that quercetin (Q) and rapamycin (Rap) inhibited P70S6K phosphorylation, partially dephosphorylated 4EBP1, and activated ERK1/2 in U937 and THP1, two leukemia cell lines. ERK1/2 inhibition by U0126 induced a stronger dephosphorylation of mTORC1 substrates and activated AKT. The concomitant inhibition of ERK1/2 and AKT further dephosphorylated 4EBP1 and further increased Q- or Rap-mediated cytotoxicity, compared to the single ERK1/2 or AKT inhibition in cells undergoing Q- or Rap-treatments. Moreover, quercetin or rapamycin reduced autophagy, particularly when used in combination with the ERK1/2 inhibitor, U0126. This effect was not dependent on TFEB localization in nuclei or cytoplasm or on the transcription of different autophagy genes, but did correlate with the reduction in protein translation due to a strong eIF2α-Ser51 phosphorylation. Thus, ERK1/2, by limiting 4EBP1 de-phosphorylation and eIF2α phosphorylation, behaves as a paladin of protein synthesis. Based on these findings, the combined inhibition of mTORC1, ERK1/2, and AKT should be considered in treatment of AML.

Comparative study of the effects of cigarette smoke versus next-generation tobacco and nicotine product extracts on inflammatory biomarkers of human monocytes

Monocytes exhibiting a pro-inflammatory phenotype play a key role in adhesion and development of atherosclerotic plaques. As an alternative to smoking, next-generation tobacco and nicotine products (NGP) are now widely used. However, little is known about their pro-inflammatory effects on monocytes. We investigated cell viability, anti-oxidant and pro-inflammatory gene and protein expression in THP-1 monocytes after exposure to aqueous smoke extracts (AqE) of a heated tobacco product (HTP), an electronic cigarette (e-cig), a conventional cigarette (3R4F) and pure nicotine (nic). Treatment with 3R4F reduced cell viability in a dose-dependent manner, whereas exposure to alternative smoking products showed no difference to control. At the highest non-lethal dose of 3R4F (20%), the following notable mRNA expression changes were observed for 3R4F, HTP, and e-cig respectively, relative to control; HMOX1 (6-fold, < 2-fold, < 2-fold), NQO1 (3.5-fold, < 2-fold, < 2-fold), CCL2 (4-fold, 3.5-fold, 2.5-fold), IL1B (4-fold, 3-fold, < 2-fold), IL8 (5-fold, 2-fold, 2-fold), TNF (2-fold, 2-fold, < 2-fold) and ICAM1 was below the 2-fold threshold for all products. With respect to protein expression, IL1B (3-fold, < 2-fold, < 2-fold) and IL8 (3.5-fold, 2-fold, 2-fold) were elevated over the 2-fold threshold, whereas CCL2, TNF, and ICAM1 were below 2-fold expression for all products. At higher doses, greater inductions were observed with all extracts; however, NGP responses were typically lower than 3R4F. In conclusion, anti-oxidative and pro-inflammatory processes were activated by all products. NGPs overall showed lower responses relative to controls than THP-1 cells exposed to 3R4F AqE.

Host determinants of TB disease as targets for HDTs development: A study protocol

Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), remains a major global health challenge. New diagnostic and therapeutic strategies are required to curb TB transmission. Here we outline a protocol to validate inflammatory proteins as potential biomarkers of TB disease and to evaluate the candidate genes as potential targets for host-directed therapy (HDT) development. Blood will be isolated from healthy, latent TB infected (LTBI) individuals and TB patients, and expression profiles of genes of interest will be determined using qPCR. A human monocytic cell line will be utilized to knock down genes of interest and to evaluate their contribution to Mtb infection. Pharmaceutical interception of target genes will be performed in peripheral blood mononuclear cells (PBMCs) infected with Mtb. This work will result in identification of TB associated inflammatory markers that can also be targeted for HDT development.

Characterization of Virulence Factors in Candida Species Causing Candidemia in a Tertiary Care Hospital in Bangkok, Thailand

Candidemia is often associated with high mortality, and Candida albicans, Candida tropicalis, Candida glabrata, and Candida parapsilosis are common causes of this disease. The pathogenicity characteristics of specific Candida spp. that cause candidemia in Thailand are poorly understood. This study aimed to characterize the virulence factors of Candida spp. Thirty-eight isolates of different Candida species from blood cultures were evaluated for their virulence properties, including exoenzyme and biofilm production, cell surface hydrophobicity, tissue invasion, epithelial cell damage, morphogenesis, and phagocytosis resistance; the identity and frequency of mutations in ERG11 contributing to azole-resistance were also determined. C. albicans had the highest epithelial cell invasion rate and phospholipase activity, with true hyphae formation, whereas C. tropicalis produced the most biofilm, hydrophobicity, protease activity, and host cell damage and true hyphae formation. ERG11 mutations Y132F and S154F were observed in all azole-resistant C. tropicalis. C. glabrata had the most hemolytic activity while cell invasion was low with no morphologic transition. C. glabrata was more easily phagocytosed than other species. C. parapsilosis generated pseudohyphae but not hyphae and did not exhibit any trends in exoenzyme production. This knowledge will be crucial for understanding the pathogenicity of Candida spp. and will help to explore antivirulence-based treatment.

Therapeutic strategies targeting pro-fibrotic macrophages in interstitial lung disease

Idiopathic pulmonary fibrosis (IPF) is the representative phenotype of interstitial lung disease where severe scarring develops in the lung interstitium. Although antifibrotic treatments are available and have been shown to slow the progression of IPF, improved therapeutic options are still needed. Recent data indicate that macrophages play essential pro-fibrotic roles in the pathogenesis of pulmonary fibrosis. Historically, macrophages have been classified into two functional subtypes, "M1" and "M2," and it is well described that "M2" or "alternatively activated" macrophages contribute to fibrosis via the production of fibrotic mediators, such as TGF-β, CTGF, and CCL18. However, highly plastic macrophages may possess distinct functions and phenotypes in the fibrotic lung environment. Thus, M2-like macrophages in vitro and pro-fibrotic macrophages in vivo are not completely identical cell populations. Recent developments in transcriptome analysis, including single-cell RNA sequencing, have attempted to depict more detailed phenotypic characteristics of pro-fibrotic macrophages. This review will outline the role and characterization of pro-fibrotic macrophages in fibrotic lung diseases and discuss the possibility of treating lung fibrosis by preventing or reprogramming the polarity of macrophages. We also utilized a systematic approach to review the literature and identify novel and promising therapeutic agents that follow this treatment strategy.

Choosing the Right Cell Line for Acute Myeloid Leukemia (AML) Research

Immortalized cell lines are widely used in vitro tools in oncology and hematology research. While these cell lines represent artificial systems and may accumulate genetic aberrations with each passage, they are still considered valuable models for pilot, preliminary, and screening studies. Despite their limitations, cell lines are cost-effective and provide repeatable and comparable results. Choosing the appropriate cell line for acute myeloid leukemia (AML) research is crucial for obtaining reliable and relevant results. Several factors should be considered when selecting a cell line for AML research, such as specific markers and genetic abnormalities associated with different subtypes of AML. It is also essential to evaluate the karyotype and mutational profile of the cell line, as these can influence the behavior and response to the treatment of the cells. In this review, we evaluate immortalized AML cell lines and discuss the issues surrounding them concerning the revised World Health Organization and the French-American-British classifications.

Label-Free Mass Spectrometry Proteomics Reveals Different Pathways Modulated in THP-1 Cells Infected with Therapeutic Failure and Drug Resistance Leishmania infantum Clinical Isolates

As the world is facing increasing difficulties to treat leishmaniasis with current therapies, deeper investigation into the molecular mechanisms responsible for both drug resistance and treatment failure (TF) is essential in drug discovery and development. So far, few available drugs cause severe side effects and have developed several resistance mechanisms. Drug resistance and TF parasite strains from clinical isolates may have acquired altered expression of proteins that characterize specific mechanisms leading to therapy inefficacy. This work aims to identify the biochemical pathways of THP-1 human monocytes infected by different Leishmania infantum clinical isolates from patients with either resistance or with TF outcome, using whole cell differential Mass Spectrometry proteomics. We have adopted network enrichment analysis to integrate the transcriptomics and the proteomic results of infected cells studies. Transferrin receptor C (TFRC) and nucleoside diphosphate kinase 3 (NDK3) were discovered as overexpressed proteins in THP-1 cells infected with paromomycin, antimony, and miltefosine resistant L. infantum lines. The overall achievements represent founding concepts to confirm new targets involved in the parasitic drug resistance and TF mechanisms, and to consider in perspective the importance of a dual host-guest pharmacological approach to treat the acute stage of the disease.

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.

Complexification of In Vitro Models of Intestinal Barriers, A True Challenge for a More Accurate Alternative Approach

The use of cell models is common to mimic cellular and molecular events in interaction with their environment. In the case of the gut, the existing models are of particular interest to evaluate food, toxicants, or drug effects on the mucosa. To have the most accurate model, cell diversity and the complexity of the interactions must be considered. Existing models range from single-cell cultures of absorptive cells to more complex combinations of two or more cell types. This work describes the existing solutions and the challenges that remain to be solved.

RAB3D/MDM2/β-catenin/c-MYC axis exacerbates the malignant behaviors of acute myeloid leukemia cells in vitro and in vivo

RAB3D, a small Ras-like GTPase involved in regulating secretory pathway, plays a cancer-promoting role in several solid tumors. However, its role in leukemogenesis remains unknown yet. Acute myeloid leukemia (AML) is a common acute leukemia with a high mortality. Here, we found the higher expression of RAB3D in bone marrow mononuclear cells derived from AML patients (n = 54) versus healthy participants (n = 20). The following loss- and gain-of-function experiments demonstrated that RAB3D promoted growth, enhanced colony formation and accelerated G1/S transition of U937, THP-1 and KG-1 AML cells. RAB3D silencing inhibited tumorigenesis of AML cells in vivo and delayed AML cells-induced death of mice. Interestingly, the expression of RAB3D is positively correlated with that of an oncogene mouse double minute 2 (MDM2) in bone marrow mononuclear cells of AML patients (r = 0.923, p < 0.001). Intracellular MDM2 was conjugated with more ubiquitins and degraded faster when RAB3D was silenced. A commonly therapeutic target of AML, β-catenin signaling, was activated by RAB3D overexpression, but deactivated after MDM2 was silenced. The RAB3D-induced proliferation acceleration and β-catenin activation were abolished by MDM2 knockdown, implying that RAB3D function by stabilizing MDM2. In addition, c-MYC, a β-catenin downstream effector, was recruited directly to the RAB3D gene promoter (-360/-349 and -136/-125 sites) and induced its transcription. Collectively, this study demonstrates that RAB3D may exacerbate the malignant behaviors of AML cells through forming a positive feedback loop with MDM2/β-catenin/c-MYC signaling. RAB3D might be a novel target of clinical AML treatment.

Endogenous secretory leukocyte protease inhibitor inhibits microbial-induced monocyte activation

In the intestine, epithelial factors condition incoming immune cells including monocytes to adapt their threshold of activation and prevent undesired inflammation. Colonic epithelial cells express Secretory Leukocyte Protease Inhibitor (SLPI), an inhibitor of NF kappa light chain enhancer of activated B cells (NF-κB) that mediates epithelial hyporesponsiveness to microbial stimuli. Uptake of extracellular SLPI by monocytes has been proposed to inhibit monocyte activation. We questioned whether monocytes can produce SLPI and whether endogenous SLPI can inhibit monocyte activation. We demonstrate that human THP-1 monocytic cells produce SLPI and that CD68⁺ SLPI-producing cells can be detected in human intestinal lamina propria. Knockdown of SLPI in human THP-1 cells significantly increased NF-κB activation and subsequent C-X-C motif chemokine ligand 8 (CXCL8) and TNF-α production in response to microbial stimulation. Reconstitution of SLPI-deficient cells with either full-length SLPI or SLPI lacking its signal peptide rescued inhibition of NF-κB activation and cytokine production, demonstrating that endogenous SLPI inhibits monocytic cell activation. Unexpectedly, exogenous SLPI did not inhibit CXCL8 or TNF-α production, despite efficient uptake. Our data argue that endogenous SLPI can regulate the threshold of activation in monocytes, thereby preventing activation by commensal bacteria in mucosal tissues.

Latent membrane protein 1 and macrophage-derived TNFα synergistically activate and mobilize invadopodia to drive invasion of nasopharyngeal carcinoma

Invadopodia are actin-rich membrane protrusions that digest the matrix barrier during cancer metastasis. Since the discovery of invadopodia, they have been visualized as localized and dot-like structures in different types of cancer cells on top of a 2D matrix. In this investigation of Epstein-Barr virus (EBV)-associated nasopharyngeal carcinoma (NPC), a highly invasive cancer frequently accompanied by neck lymph node and distal organ metastases, we revealed a new form of invadopodium with mobilizing features. Integration of live-cell imaging and molecular assays revealed the interaction of macrophage-released TNFα and EBV-encoded latent membrane protein 1 (LMP1) in co-activating the EGFR/Src/ERK/cortactin and Cdc42/N-WASP signaling axes for mobilizing the invadopodia with lateral movements. This phenomenon endows the invadopodia with massive degradative power, visualized as a shift of focal dot-like digestion patterns on a 2D gelatin to a dendrite-like digestion pattern. Notably, single stimulation of either LMP1 or TNFα could only enhance the number of ordinary dot-like invadopodia, suggesting that the EBV infection sensitizes the NPC cells to form mobilizing invadopodia when encountering a TNFα-rich tumor microenvironment. This study unveils the interplay of EBV and stromal components in driving the invasive potential of NPC via unleashing the propulsion of invadopodia in overcoming matrix hurdles. © 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Comparing the Toxicological Responses of Pulmonary Air-Liquid Interface Models upon Exposure to Differentially Treated Carbon Fibers

In recent years, the use of carbon fibers (CFs) in various sectors of industry has been increasing. Despite the similarity of CF degradation products to other toxicologically relevant materials such as asbestos fibers and carbon nanotubes, a detailed toxicological evaluation of this class of material has yet to be performed. In this work, we exposed advanced air-liquid interface cell culture models of the human lung to CF. To simulate different stresses applied to CF throughout their life cycle, they were either mechanically (mCF) or thermo-mechanically pre-treated (tmCF). Different aspects of inhalation toxicity as well as their possible time-dependency were monitored. mCFs were found to induce a moderate inflammatory response, whereas tmCF elicited stronger inflammatory as well as apoptotic effects. Furthermore, thermal treatment changed the surface properties of the CF resulting in a presumed adhesion of the cells to the fiber fragments and subsequent cell loss. Triple-cultures encompassing epithelial, macrophage, and fibroblast cells stood out with an exceptionally high inflammatory response. Only a weak genotoxic effect was detected in the form of DNA strand breaks in mono- and co-cultures, with triple-cultures presenting a possible secondary genotoxicity. This work establishes CF fragments as a potentially harmful material and emphasizes the necessity of further toxicological assessment of existing and upcoming advanced CF-containing materials.

Novel 3D Flipwell system that models gut mucosal microenvironment for studying interactions between gut microbiota, epithelia and immunity

Gut mucosa consists of stratified layers of microbes, semi-permeable mucus, epithelium and stroma abundant in immune cells. Although tightly regulated, interactions between gut commensals and immune cells play indispensable roles in homeostasis and cancer pathogenesis in the body. Thus, there is a critical need to develop a robust model for the gut mucosal microenvironment. Here, we report our novel co-culture utilizing 3D Flipwell system for establishing the stratified layers of discrete mucosal components. This method allows for analyzing synchronous effects of test stimuli on gut bacteria, mucus, epithelium and immune cells, as well as their crosstalks. In the present report, we tested the immuno-stimulatory effects of sepiapterin (SEP, the precursor of the cofactor of nitric oxide synthase (NOS)-BH₄) on the gut mucosal community. We previously reported that SEP effectively reprogrammed tumor-associated macrophages and inhibited breast tumor cell growth. In our co-cultures, SEP largely promoted mucus integrity, bacterial binding, and M1-like polarization of macrophages. Conversely, these phenomena were absent in control-treated cultures. Our results demonstrate that this novel co-culture may serve as a robust in vitro system to recapitulate the effects of pharmacological agents on the gut mucosal microenvironment, and could potentially be expanded to test the effects outside the gut.

The Monocytic Cell Line THP-1 as a Validated and Robust Surrogate Model for Human Dendritic Cells

We have implemented an improved, cost-effective, and highly reproducible protocol for a simple and rapid differentiation of the human leukemia monocytic cell line THP-1 into surrogates for immature dendritic cells (iDCs) or mature dendritic cells (mDCs). The successful differentiation of THP-1 cells into iDCs was determined by high numbers of cells expressing the DC activation markers CD54 (88%) and CD86 (61%), and the absence of the maturation marker CD83. The THP-1-derived mDCs are characterized by high numbers of cells expressing CD54 (99%), CD86 (73%), and the phagocytosis marker CD11b (49%) and, in contrast to THP-1-derived iDCs, CD83 (35%) and the migration marker CXCR4 (70%). Treatment of iDCs with sensitizers, such as NiSO4 and DNCB, led to high expression of CD54 (97%/98%; GMFI, 3.0/3.2-fold induction) and CD86 (64%/96%; GMFI, 4.3/3.2-fold induction) compared to undifferentiated sensitizer-treated THP-1 (CD54, 98%/98%; CD86, 55%/96%). Thus, our iDCs are highly suitable for toxicological studies identifying potential sensitizing or inflammatory compounds. Furthermore, the expression of CD11b, CD83, and CXCR4 on our iDC and mDC surrogates could allow studies investigating the molecular mechanisms of dendritic cell maturation, phagocytosis, migration, and their use as therapeutic targets in various disorders, such as sensitization, inflammation, and cancer.

PpSP32, the Phlebotomus papatasi immunodominant salivary protein, exerts immunomodulatory effects on human monocytes, macrophages, and lymphocytes

BACKGROUND

The saliva of sand flies, vectors of Leishmania parasites, contains several components that exert pharmacological activity facilitating the acquisition of blood by the insect and contributing to the establishment of infection. Previously, we demonstrated that PpSP32 is the immunodominant salivary antigen in humans exposed to Phlebotomus papatasi bites and validated its usefulness as a predictive biomarker of disease. PpSP32, whose functions are little known to date, is an intriguing protein due to its involvement in the etiopathogenesis of pemphigus, an auto-immune disease. Herein, we aimed to better decipher its role through the screening of several immunomodulatory activity either on lymphocytes or on monocytes/macrophages.

METHODS

Peripheral mononuclear cells from healthy volunteers were stimulated with anti-CD3/anti-CD28 antibodies, phytohemagglutinin, phorbol 12-myristate 13-acetate/ionomycin, or lipopolysaccharide in the presence of increasing doses of PpSP32. Cell proliferation was measured after the addition of tritiated thymidine. Monocyte activation was tested by analyzing the expression of CD86 and HLA-DR molecules by flow cytometry. Cytokine production was analyzed in culture supernatants by ELISA. THP-1-derived macrophages were stimulated with LPS in the presence of increasing doses of PpSP32, and cytokine production was analyzed in culture supernatants by ELISA and multiplex technique. The effect of PpSP32 on NF-kB signaling was tested by Western blot. The anti-inflammatory activity of PpSP32 was assessed in vivo in an experimental inflammatory model of carrageenan-induced paw edema in rats.

RESULTS

Our data showed that PpSP32 down-modulated the expression of activation markers in LPS-stimulated monocytes and THP1-derived macrophages. This protein negatively modulated the secretion of Th1 and Th2 cytokines by human lymphocytes as well as pro-inflammatory cytokines by monocytes, and THP1-derived macrophages. PpSP32 treatment led to a dose-dependent reduction of IκB phosphorylation. When PpSP32 was injected into the paw of carrageenan-injected rats, edema was significantly reduced.

CONCLUSIONS

Our data indicates that PpSP32 induces a potent immunomodulatory effect on monocytes and THP-1-derived macrophages. This inhibition could be mediated, among others, by the modulation of the NF-kB signaling pathway. The anti-inflammatory activity of PpSP32 was confirmed in vivo in the carrageenan-induced paw edema model in rats.

Studies on the contribution of PPAR Gamma to tuberculosis physiopathology

Introduction

Tuberculosis (TB) is a major health problem characterized by an immuno-endocrine imbalance: elevated plasma levels of cortisol and pro- and anti-inflammatory mediators, as well as reduced levels of dehydroepiandrosterone. The etiological agent, Mycobacterium tuberculosis (Mtb), is captured by pulmonary macrophages (Mf), whose activation is necessary to cope with the control of Mtb, however, excessive activation of the inflammatory response also leads to tissue damage. Glucocorticoids (GC) are critical elements to counteract the immunoinflammatory reaction, and peroxisome proliferator-activated receptors (PPARs) are also involved in this regard. The primary forms of these receptors are PPARϒ, PPARα, and PPARβ/δ, the former being the most involved in anti-inflammatory responses. In this work, we seek to gain some insight into the contribution of PPARϒ in immuno-endocrine-metabolic interactions by focusing on clinical studies in pulmonary TB patients and in vitro experiments on a Mf cell line.

Methods and results

We found that TB patients, at the time of diagnosis, showed increased expression of the PPARϒ transcript in their peripheral blood mononuclear cells, positively associated with circulating cortisol and related to disease severity. Given this background, we investigated the expression of PPARϒ (RT-qPCR) in radiation-killed Mtb-stimulated human Mf. The Mtb stimulation of Mf derived from the human line THP1 significantly increased the expression of PPARϒ, while the activation of this receptor by a specific agonist decreased the expression of pro- and anti-inflammatory cytokines (IL-1β and IL-10). As expected, the addition of GC to stimulated cultures reduced IL-1β production, while cortisol treatment together with the PPARϒ agonist lowered the levels of this proinflammatory cytokine in stimulated cultures. The addition of RU486, a glucocorticoid receptor antagonist, only reversed the inhibition produced by the addition of GC.

Conclusion

The current results provide a stimulating background for further analysis of the interconnection between PPARs and steroid hormones in the context of Mtb infection.

Classic psychedelics do not affect T cell and monocyte immune responses

INTRODUCTION

Classic psychedelics have been shown to exert therapeutic potential for the treatment of various psychiatric disorders, neuropsychiatric diseases, and neuronal damage. Besides their psychopharmacological activity, psychedelics have been reported to modulate immune functions. There has thus far been a sparse exploration of the direct immune-modulating effect of psychedelics on human immune cells in vitro. Since T cells are key mediators of several immune functions, inhibition of their function would increase the risk of infections.

METHODS

We investigated the effect of the classic psychedelics lysergic acid diethylamide (LSD), psilocin, N,N-dimethyltryptamine (DMT), and mescaline on the proliferation and stimulated cytokine release of primary human T lymphocytes and on the stimulated NF-κB induction of monocytes.

RESULTS

We did not observe any relevant direct immune-modulatory effects of the tested classic psychedelics in either cell line.

DISCUSSION

We concluded that LSD, psilocin, DMT, or mescaline did not directly stimulate the proliferation or cytokine secretion of primary human T lymphocytes or stimulate NF-κB induction of monocytes. Our findings support the future safe use of classic psychedelics in assisted psychotherapy in patients with life-threatening diseases where immune suppression and diminished immune function would be detrimental.

In Vitro Study of TLR4-NLRP3-Inflammasome Activation in Innate Immune Response

Toll-like receptors (TLRs) are pivotal players in mediating immune responses. TLR4 is the main receptor for LPS, a strong activator of immune cells. LPS/TLR4-dependent pathway, by inducing NF-κB activation, is responsible for the release of several mediators, including IL-1β, one of the most powerful cytokines deeply involved in inflammatory and immune responses. The same pathway is also involved in NLRP3-inflammasome activation, essential for IL-1β maturation. NLRP3 is a major component of innate immune responses, being a crucial player of host immune defense against virus, bacterial, or fungal infections. NLRP3-inflammasome and IL-1β hyperactivation have been associated to the pathogenesis of a wide range of disorders and represent therapeutic targets for the development of new treatments of inflammasome-driven inflammatory and autoimmune diseases.Here, we describe an in vitro protocol to induce LPS/TLR4-dependent NLRP3-inflammasome/IL-1β activation in immune cells, in order to provide a useful assay to study the efficacy of different anti-inflammatory/immune-modulatory agents.

Analysis of the noncoding RNA regulatory networks of H37Rv- and H37Rv△1759c-infected macrophages

Noncoding RNAs regulate the process of Mycobacterium tuberculosis (M. tb) infecting the host, but there is no simultaneous transcriptional information of long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs) and the global regulatory networks of non-coding RNA. Rv1759c, a virulence factor, is a member of protein family containing the proline-glutamic acid (PE) in M. tb, which can increase M. tb survival. To reveal the noncoding RNA regulatory networks and the effect of Rv1759c on non-coding RNA expression during M. tb infection, we collected samples of H37Rv- and H37Rv△1759c-infected macrophages and explored the full transcriptome expression profile. We found 356 mRNAs, 433 lncRNAs, 168 circRNAs, and 12 miRNAs differentially expressed during H37Rv infection, 356 mRNAs, 433 lncRNAs, 168 circRNAs, and 12 miRNAs differentially expressed during H37Rv△1759c infection. We constructed lncRNA/circRNA-miRNA-mRNA regulatory networks during H37Rv and H37Rv△1759c infection. We demonstrated the role of one of the hubs of the networks, hsa-miR-181b-3p, for H37Rv survival in macrophages. We discovered that the expression changes of 68 mRNAs, 92 lncRNAs, 26 circRNAs, and 3 miRNAs were only related to the deletion of Rv1759c by comparing the transcription profiles of H37Rv and H37Rv△1759c. Here, our study comprehensively characterizes the transcriptional profiles in THP1-derived-macrophages infected with H37Rv and H37Rv△1759c, which provides support and new directions for in-depth exploration of noncoding RNA and PE/PPE family functions during the infection process.

In Vitro Effects of Bisphenol Analogs on Immune Cells Activation and Th Differentiation

AIMS

Investigate the immunomodulatory effects of bisphenols in the THP-1 cell line and peripheral blood mononuclear cells in response to lipopolysaccharide (LPS) activation or to phorbol 12-myristate 13-acetate (PMA) and ionomycin.

BACKGROUND

We have previously demonstrated the usefulness of the evaluation of RACK1 expression as a link between endocrine disrupting activity and the immunotoxic effect of xenobiotics. We demonstrated that while BPA and BPAF reduced RACK1 expression, BPS was able to increase it.

OBJECTIVE

Bisphenol A (BPA) is one of the most commonly used chemicals in the manufacturing of polycarbonate plastics and plastic consumer products. Its endocrine disrupting (ED) potential and changes in European regulations have led to replacing BPA in many uses with structurally similar chemicals, like bisphenol AF (BPAF) and bisphenol S (BPS). However, emerging data indicated that bisphenol analogues may not be safer than BPA both in toxic effects and ED potential.

METHODS

THP-1 cell line and peripheral blood mononuclear cells were activated with lipopolysaccharide (LPS) or with phorbol 12-myristate 13-acetate (PMA) and ionomycin.

RESULTS

BPA and BPAF decreased LPS-induced expression of surface markers and the release of pro-inflammatory cytokines, while BPS increased LPS-induced expression of CD86 and cytokines. BPA, BPAF, and BPS affected PMA/ionomycin-induced T helper differentiation and cytokine release with gender-related alterations in some parameters investigated.

CONCLUSION

Data confirm that bisphenols can modulate immune cell differentiation and activation, further supporting their immunotoxic effects.

Invasive Streptococcal Infection Can Lead to the Generation of Cross-Strain Opsonic Antibodies

The human pathogen Streptococcus pyogenes causes substantial morbidity and mortality. It is unclear if antibodies developed after infections with this pathogen are opsonic and if they are strain specific or more broadly protective. Here, we quantified the opsonic-antibody response following invasive S. pyogenes infection. Four patients with S. pyogenes bacteremia between 2018 and 2020 at Skåne University Hospital in Lund, Sweden, were prospectively enrolled. Acute- and convalescent-phase sera were obtained, and the S. pyogenes isolates were genome sequenced (emm118, emm85, and two emm1 isolates). Quantitative antibody binding and phagocytosis assays were used to evaluate isolate-dependent opsonic antibody function in response to infection. Antibody binding increased modestly against the infecting isolate and across emm types in convalescent- compared to acute-phase sera for all patients. For two patients, phagocytosis increased in convalescent-phase serum both for the infecting isolate and across types. The increase was only across types for one patient, and one had no improvement. No correlation to the clinical outcomes was observed. Invasive S. pyogenes infections result in a modestly increased antibody binding with differential opsonic capacity, both nonfunctional binding and broadly opsonic binding across types. These findings question the dogma that an invasive infection should lead to a strong type-specific antibody increase rather than a more modest but broadly reactive response, as seen in these patients. Furthermore, our results indicate that an increase in antibody titers might not be indicative of an opsonic response and highlight the importance of evaluating antibody function in S. pyogenes infections. IMPORTANCE The bacterium Streptococcus pyogenes is a common cause of both mild and severe human diseases resulting in substantial morbidity and mortality each year. No vaccines are available, and our understanding of the antibody response to this human pathogen is still incomplete. Here, we carefully analyzed the opsonic antibody response following invasive infection in four patients. Unexpectedly, the patients did not always generate opsonic antibodies against the specific infecting strain. Instead, we found that some patients could generate cross-opsonic antibodies, leading to phagocytosis of bacteria across strains. The emergence of cross-opsonic antibodies is likely important for long-term immunity against S. pyogenes. Our findings question the dogma that mostly strain-specific immunity is developed after infection and add to our overall understanding of how immunity to S. pyogenes can evolve.

TLR4/CD14/MD2 Revealed as the Limited Toll-like Receptor Complex for Chlamydia trachomatis-Induced NF-κB Signaling

Chlamydia trachomatis (Ct) is the most common cause of genital tract infections as well as preventable blindness worldwide. Pattern recognition receptors such as toll-like receptors (TLRs) represent the initial step in recognizing pathogenic microorganisms and are crucial for the initiation of an appropriate immune response. However, our understanding of TLR-signaling in Chlamydia-infected immune cells is incomplete. For a better comprehension of pathological inflammatory responses, robust models for interrogating TLR-signaling upon chlamydial infections are needed. To analyze the TLR response, we developed and utilized a highly sensitive and selective fluorescent transcriptional cellular reporter system to measure the activity of the transcription factor NF-κB. Upon incubation of the reporter cells with different preparations of Ct, we were able to pinpoint which components of TLRs are involved in the recognition of Ct. We identified CD14 associated with unique characteristics of different serovars as the crucial factor of the TLR4/CD14/MD2 complex for Ct-mediated activation of the NF-κB pathway. Furthermore, we found the TLR4/CD14/MD2 complex to be decisive for the uptake of Ct-derived lipopolysaccharides but not for infection and replication of Ct. Imaging flow cytometry provided information about inclusion formation in myeloid- as well as lymphocytic cells and was highest for Ct L2 with at least 25% of inclusion forming cells. Ct E inclusion formation was eminent in Jurkat cells without CD14 expression (11.1%). Thus, our model enables to determine Ct uptake and signal induction by pinpointing individual components of the recognition and signaling pathways to better understand the immune response towards infectious pathogens.

Single‐Cell Profiling Reveals Functional Heterogeneity and Serial Killing in Human Peripheral and Ex Vivo‐Generated CD34+ Progenitor‐Derived Natural Killer Cells

Increasing evidence suggests that natural killer (NK) cells are composed of distinct functional subsets. This multifunctional role has made them an attractive choice for anticancer immunotherapy. A functional NK cell repertoire is generated through cellular education, resulting in a heterogeneous NK cell population with distinct capabilities responding to different stimuli. The application of a high-throughput droplet-based microfluidic platform allows monitoring of NK cell-target cell interactions at the single-cell level and in real-time. A variable response of single NK cells toward different target cells is observed, and a distinct population of NK cells (serial killers) capable of inducing multiple target lysis is identified. By assessing the cytotoxic dynamics, it is shown that single umbilical cord blood-derived CD34+ hematopoietic progenitor (HPC)-NK cells display superior antitumor cytotoxicity. With an integrated analysis of cytotoxicity and cytokine secretion, it is shown that target cell interactions augment cytotoxic as well as secretory behavior of NK cells. By providing an integrated assessment of NK cell functions by microfluidics, this study paves the way to further functionally characterize NK cells ultimately aimed to improve cancer immunotherapy.

Worldwide productivity and research trend of publications concerning glioma-associated macrophage/microglia: A bibliometric study

Glioma-associated macrophage/microglia (GAM) represents a key player in shaping a unique glioma ecosystem to facilitate tumor progression and therapeutic resistance. Numerous studies have been published concerning GAM, but no relevant bibliometric study has been performed yet. Our bibliometric study aimed to comprehensively summarize and analyze the global scientific output, research hotspots, and trendy topics of publications on GAM over time. Data on publications on GAM were collected using the Web of Science (WoS). The search date was 16 January 2022, and the publications were collected from 2002 to 2021. Totally, 1,224 articles and reviews were incorporated and analyzed in the current study. It showed that the annual publications concerning GAM kept increasing over the past 20 years. The United States had the largest number of publications and total citations. Holland, Kettenmann, and Gutmann were the top three authors in terms of citation frequency. Neuro-oncology represented the most influential journal in GAM studies, with the highest H-index, total citations, and publication numbers. The paper published by Hambardzumyan in 2016 had the highest local citations. Additionally, the analysis of keywords implied that "prognosis," "tumor microenvironment," and "immunotherapy" might become research hotspots. Furthermore, trendy topics in GAM studies suggested that "immune infiltration," "immune microenvironment," "bioinformatics," "prognosis," and "immunotherapy" deserved additional attention. In conclusion, this bibliometric study comprehensively analyzed the publication trend of GAM studies for the past 20 years, in which the research hotspots and trendy topics were also uncovered. This information offered scholars critical references for conducting in-depth studies on GAM in the future.

Acquisition of antibodies to Plasmodium falciparum and Plasmodium vivax antigens in pregnant women living in a low malaria transmission area of Brazil

BACKGROUND

Pregnant women have increased susceptibility to Plasmodium falciparum malaria and acquire protective antibodies over successive pregnancies. Most studies that investigated malaria antibody responses in pregnant women are from high transmission areas in sub-Saharan Africa, while reports from Latin America are scarce and inconsistent. The present study sought to explore the development of antibodies against P. falciparum and Plasmodium vivax antigens in pregnant women living in a low transmission area in the Brazilian Amazon.

METHODS

In a prospective cohort study, plasma samples from 408 pregnant women (of whom 111 were infected with P. falciparum, 96 had infections with P. falciparum and P. vivax, and 201 had no Plasmodium infection) were used to measure antibody levels. Levels of IgG and opsonizing antibody to pregnancy-specific variant surface antigens (VSAs) on infected erythrocytes (IEs), 10 recombinant VAR2CSA Duffy binding like (DBL domains), 10 non-pregnancy-specific P. falciparum merozoite antigens, and 10 P. vivax antigens were measured by flow cytometry, ELISA, and multiplex assays. Antibody levels and seropositivity among the groups were compared.

RESULTS

Antibodies to VSAs on P. falciparum IEs were generally low but were higher in currently infected women and women with multiple P. falciparum episodes over pregnancy. Many women (21%-69%) had antibodies against each individual VAR2CSA DBL domain, and antibodies to DBLs correlated with each other (r ≥ 0.55, p < 0.0001), but not with antibody to VSA or history of infection. Infection with either malaria species was associated with higher seropositivity rate for antibodies against P. vivax proteins, adjusted odds ratios (95% CI) ranged from 5.6 (3.2, 9.7), p < 0.0001 for PVDBPII-Sal1 to 15.7 (8.3, 29.7), p < 0.0001 for PvTRAg_2.

CONCLUSIONS

Pregnant Brazilian women had low levels of antibodies to pregnancy-specific VSAs that increased with exposure. They frequently recognized both VAR2CSA DBL domains and P. vivax antigens, but only the latter varied with infection. Apparent antibody prevalence is highly dependent on the assay platform used.

Alternative Methods for Skin-Sensitization Assessment

Skin sensitization is a term used to refer to the regulatory hazard known as allergic contact dermatitis (ACD) in humans or contact hypersensitivity in rodents, an important health endpoint considered in chemical hazard and risk assessments. Information on skin sensitization potential is required in various regulatory frameworks, such as the Directive of the European Parliament and the Council on Registration, Evaluation and Authorization of Chemicals (REACH). The identification of skin-sensitizing chemicals previously required the use of animal testing, which is now being replaced by alternative methods. Alternative methods in the field of skin sensitization are based on the measurement or prediction of key events (KE), i.e., (i) the molecular triggering event, i.e., the covalent binding of electrophilic substances to nucleophilic centers in skin proteins; (ii) the activation of keratinocytes; (iii) the activation of dendritic cells; (iv) the proliferation of T cells. This review article focuses on the current state of knowledge regarding the methods corresponding to each of the key events in skin sensitization and considers the latest trends in the development and modification of these methods.

Identification of a Novel Curcumin Derivative Influencing Notch Pathway and DNA Damage as a Potential Therapeutic Agent in T-ALL

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematological malignancy considered curable by modern clinical management. Nevertheless, the prognosis for T-ALL high-risk cases or patients with relapsed and refractory disease is still dismal. Therefore, there is a keen interest in developing more efficient and less toxic therapeutic approaches. T-ALL pathogenesis is associated with Notch signaling alterations, making this pathway a highly promising target in the fight against T-ALL. Here, by exploring the anti-leukemic capacity of the natural polyphenol curcumin and its derivatives, we found that curcumin exposure impacts T-ALL cell line viability and decreases Notch signaling in a dose- and time-dependent fashion. However, our findings indicated that curcumin-mediated cell outcomes did not depend exclusively on Notch signaling inhibition, but might be mainly related to compound-induced DNA-damage-associated cell death. Furthermore, we identified a novel curcumin-based compound named CD2066, endowed with potentiated anti-proliferative activity in T-ALL compared to the parent molecule curcumin. At nanomolar concentrations, CD2066 antagonized Notch signaling, favored DNA damage, and acted synergistically with the CDK1 inhibitor Ro3306 in T-ALL cells, thus representing a promising novel candidate for developing therapeutic agents against Notch-dependent T-ALL.

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).

A multifaceted high-throughput assay for probing antigen-specific antibody-mediated primary monocyte phagocytosis and downstream functions

Monocytes are highly versatile innate immune cells responsible for pathogen clearance, innate immune coordination, and induction of adaptive immunity. Monocytes can directly and indirectly integrate pathogen-destructive instructions and contribute to disease control via pathogen uptake, presentation, or the release of cytokines. Indirect pathogen-specific instructions are conferred via Fc-receptor signaling and triggered by antibody opsonized material. Given the tremendous variation in polyclonal humoral immunity, defining the specific antibody-responses able to arm monocytes most effectively remains incompletely understood. While monocyte cell line-based assays have been used previously, cell lines may not faithfully recapitulate the full biology of monocytes. Thus, here we describe a multifaceted antigen-specific method for probing antibody-dependent primary monocyte phagocytosis (ADMP) and secondary responses. The assay not only reliably captures phagocytic uptake of immune complexes, but also detects unique changes in surface markers and cytokine secretions profiles, poorly detected by monocytic cell lines. The assay captures divergent polyclonal-monocyte recruiting activity across subjects with varying SARS-CoV-2 disease severity and also revealed biological nuances in Fc-mutant monoclonal antibody activity related to differences in Fc-receptor binding. Thus, the ADMP assay is a flexible assay able to provide key insights into the role of humoral immunity in driving monocyte phenotypic transitions and downstream functions across many diseases.

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.

Longitudinal Characterization of Phagocytic and Neutralization Functions of Anti-Spike Antibodies in Plasma of Patients after Severe Acute Respiratory Syndrome Coronavirus 2 Infection

Phagocytic responses by effector cells to opsonized viruses have been recognized to play a key role in antiviral immunity. Limited data on coronavirus disease 2019 suggest that the role of Ab-dependent and -independent phagocytosis may contribute to the observed immunological and inflammatory responses; however, their development, duration, and role remain to be fully elucidated. In this study of 62 acute and convalescent patients, we found that patients with acute coronavirus disease 2019 can mount a phagocytic response to autologous plasma-opsonized Spike protein-coated microbeads as early as 10 d after symptom onset, while heat inactivation of this plasma caused 77-95% abrogation of the phagocytic response and preblocking of Fc receptors showed variable 18-60% inhibition. In convalescent patients, phagocytic response significantly correlated with anti-Spike IgG titers and older patients, while patients with severe disease had significantly higher phagocytosis and neutralization functions compared with patients with asymptomatic, mild, or moderate disease. A longitudinal subset of the convalescent patients over 12 mo showed an increase in plasma Ab affinity toward Spike Ag and preservation of phagocytic and neutralization functions, despite a decline in the anti-Spike IgG titers by >90%. Our data suggest that early phagocytosis is primarily driven by heat-liable components of the plasma, such as activated complements, while anti-Spike IgG titers account for the majority of observed phagocytosis at convalescence. Longitudinally, a significant increase in the affinity of the anti-Spike Abs was observed that correlated with the maintenance of both the phagocytic and neutralization functions, suggesting an improvement in the quality of the Abs.

Development of a Novel In Vitro Immuno-Competent Model of Dry Eye Disease and Its Use to Evaluate the Efficacy of an Ocular Surface Modulator

PURPOSE

To develop an in vitro model of severe immunocompetent-dry eye disease (ic-DED) and to investigate the mechanism of action of a T-lysial ocular surface modulator.

MATERIALS AND METHODS

The reconstructed human corneal epithelium (HCE) was exposed to dryness stimuli. THP-1 cell infiltration into HCE was monitored at 4 h and 24 h from T-lysial application by immunohistochemistry (CD14, CD86, AQP3) and molecular biology (AQP3, TLR4 and TNF-α).

RESULTS

A reduction of CD14, CD86 and AQP3 was observed after T-lysial treatment at 24 h. TLR4 was overexpressed in ic-DED model and downregulated by T-Lysial after 24 h. TNF-α expression was not modified.

CONCLUSION

The ic-DED model can be used to monitor the migration and differentiation of THP-1 into HCE. T-lysial was found to exert anti-inflammatory activity. This experimental model is a promising tool to study the crosstalk between epithelial and immune cells, providing new insights on the mechanisms of DED onset.

PdpC, a secreted effector protein of the type six secretion system, is required for erythrocyte invasion by Francisella tularensis LVS

Francisella tularensis is a gram negative, intracellular pathogen that is the causative agent of the potentially fatal disease, tularemia. During infection, F. tularensis is engulfed by and replicates within host macrophages. Additionally, this bacterium has also been shown to invade human erythrocytes and, in both cases, the Type Six Secretion System (T6SS) is required for these host-pathogen interaction. One T6SS effector protein, PdpC, is important for macrophage infection, playing a role in phagolysosomal escape and intracellular replication. To determine if PdpC also plays a role in erythrocyte invasion, we constructed a pdpC-null mutant in the live vaccine strain, F. tularensis LVS. We show that PdpC is required for invasion of human and sheep erythrocytes during in vitro assays and that reintroduction of a copy of pdpC, in trans, rescues this phenotype. The interaction with human erythrocytes was further characterized using double-immunofluorescence microscopy to show that PdpC is required for attachment of F. tularensis LVS to erythrocytes as well as invasion. To learn more about the role of PdpC in erythrocyte invasion we generated a strain of F. tularensis LVS expressing pdpC-emgfp. PdpC-EmGFP localizes as discrete foci in a subset of F. tularensis LVS cells grown in broth culture and accumulates in erythrocytes during invasion assays. Our results are the first example of a secreted effector protein of the T6SS shown to be involved in erythrocyte invasion and indicate that PdpC is secreted into erythrocytes during invasion.

Efficient production of inhibitor-free foamy virus glycoprotein-containing retroviral vectors by proteoglycan-deficient packaging cells

Foamy viruses (FVs) or heterologous retroviruses pseudotyped with FV glycoprotein enable transduction of a great variety of target tissues of disparate species. Specific cellular entry receptors responsible for this exceptionally broad tropism await their identification. Though, ubiquitously expressed heparan sulfate proteoglycan (HS-PG) is known to serve as an attachment factor of FV envelope (Env)-containing virus particles, greatly enhancing target cell permissiveness. Production of high-titer, FV Env-containing retroviral vectors is strongly dependent on the use of cationic polymer-based transfection reagents like polyethyleneimine (PEI). We identified packaging cell-surface HS-PG expression to be responsible for this requirement. Efficient release of FV Env-containing virus particles necessitates neutralization of HS-PG binding sites by PEI. Remarkably, remnants of PEI in FV Env-containing vector supernatants, which are not easily removable, negatively impact target cell transduction, in particular those of myeloid and lymphoid origin. To overcome this limitation for production of FV Env-containing retrovirus supernatants, we generated 293T-based packaging cell lines devoid of HS-PG by genome engineering. This enabled, for the first, time production of inhibitor-free, high-titer FV Env-containing virus supernatants by non-cationic polymer-mediated transfection. Depending on the type of virus, produced titers were 2- to 10-fold higher compared with those obtained by PEI transfection.

THP-1 cell line model for tuberculosis: A platform for in vitro macrophage manipulation

Macrophages are large mononuclear phagocytic cells that play a vital role in the immune response. They are present in all body tissues with extremely heterogeneous and plastic phenotypes that adapt to the organs and tissues in which they live and respond in the first-line against invading microorganisms. Tuberculosis (TB) is caused by the pathogenic bacteria Mycobacterium tuberculosis (Mtb), which is among the top 10 global infectious agents and the leading cause of mortality, ranking above human immunodeficiency virus (HIV), as a single infectious agent. Macrophages, upon Mtb infection, not only phagocytose the bacteria and present the antigens to T-cells, but also react rapidly by developing antimycobacterial immune response depending highly on the production of cytokines. However, Mtb is also capable of intracellular survival in instances of sub-optimal activation of macrophages. Hence, several systems have been established to evaluate the Mtb-macrophage interaction, where the THP-1 monocytes have been developed as an attractive model for in vitro polarized monocyte-derived macrophages. This model is extensively used for Mtb as well as other intracellular bacterial studies. Herein, we have summarized the updated implications of the THP-1 model for TB-related studies and discussed the pros and cons compared to other cell models of TB.

Wall Teichoic Acids Facilitate the Release of Toxins from the Surface of Staphylococcus aureus

A major feature of the pathogenicity of Staphylococcus aureus is its ability to secrete cytolytic toxins. This process involves the translocation of the toxins from the cytoplasm through the bacterial membrane and the cell wall to the external environment. The process of their movement through the membrane is relatively well defined, involving both general and toxin-specific secretory systems. Movement of the toxins through the cell wall was considered to involve the passive diffusion of the proteins through the porous cell wall structures; however, recent work suggests that this is more complex, and here we demonstrate a role for the wall teichoic acids (WTA) in this process. Utilizing a genome-wide association approach, we identified a polymorphism in the locus encoding the WTA biosynthetic machinery as associated with the cytolytic activity of the bacteria. We verified this association using an isogenic mutant set and found that WTA are required for the release of several cytolytic toxins from the bacterial cells. We show that this effect is mediated by a change in the electrostatic charge across the cell envelope that results from the loss of WTA. As a major target for the development of novel therapeutics, it is important that we fully understand the entire process of cytolytic toxin production and release. These findings open up a new aspect to the process of toxin release by a major human pathogen while also demonstrating that clinical isolates can utilize WTA production to vary their cytotoxicity, thereby altering their pathogenic capabilities. IMPORTANCE The production and release of cytolytic toxins is a critical aspect for the pathogenicity of many bacterial pathogens. In this study, we demonstrate a role for wall teichoic acids, molecules that are anchored to the peptidoglycan of the bacterial cell wall, in the release of toxins from S. aureus cells into the extracellular environment. Our findings suggest that this effect is mediated by a gradient of electrostatic charge which the presence of the negatively charged WTA molecules create across the cell envelope. This work brings an entirely new aspect to our understanding of the cytotoxicity of S. aureus and demonstrates a further means by which this major human pathogen can adapt its pathogenic capabilities.

MARCKS Is an Essential Regulator of Reactive Oxygen Species Production in the Monocytic Cell Type

Myristoylated alanine-rich C-kinase substrate (MARCKS) is a ubiquitous protein mediating versatile effects in a variety of cell types, including actin crosslinking, signal transduction, and intracellular transport processes. MARCKS’s functional role in monocyte/macrophages, however, has not yet been adequately addressed. Thus, the aim of this study was to further elucidate the impact of MARCKS on central cellular functions of monocytic cells. To address this topic, we generated monocytic THP-1 (Tohoku Hospital Pediatrics-1)-derived MARCKS wildtype and knockout (KO) cells using the CRISPR/Cas9 technique. Remarkably, in the absence of MARCKS, both total and intracellular reactive oxygen species (ROS) production were strongly suppressed but restored following transient MARCKS re-transfection. In contrast, proliferation, differentiation, cytokine expression, and phagocytosis remained unaltered. A complete inhibition of ROS production could also be achieved in THP-1-derived PKCβ KO cells or in PKC inhibitor Staurosporine-treated primary human monocytes. MARCKS deficiency also involved reduced basal Akt phosphorylation and delayed re-phosphorylation. Further analyses indicated that long-term TNF pre-incubation strongly enhances monocytic ROS production, which was completely blocked in MARCKS and PKCβ KO cells. Collectively, our study demonstrates that MARCKS is an essential molecule enabling ROS production by monocytic cells and suggests that MARCKS is part of a signal cascade involved in ROS formation.

Characterization of sabatolimab, a novel immunotherapy with immuno-myeloid activity directed against TIM-3 receptor

Objectives

Sabatolimab is a humanized monoclonal antibody (hIgG4, S228P) directed against human T-cell immunoglobulin domain and mucin domain-3 (TIM-3). Herein, we describe the development and characterization of sabatolimab.

Methods

Sabatolimab was tested for binding to its target TIM-3 and blocking properties. The functional effects of sabatolimab were tested in T-cell killing and myeloid cell cytokine assays. Antibody-mediated cell phagocytosis (ADCP) by sabatolimab was also assessed.

Results

Sabatolimab was shown to (i) enhance T-cell killing and inflammatory cytokine production by dendritic cells (DCs); (ii) facilitate the phagocytic uptake of TIM-3-expressing target cells; and (iii) block the interaction between TIM-3 and its ligands PtdSer/galectin-9.

Conclusion

Taken together, our results support both direct anti-leukemic effects and immune-mediated modulation by sabatolimab, reinforcing the notion that sabatolimab represents a novel immunotherapy with immuno-myeloid activity, holding promise for the treatment of myeloid cell neoplasms.

The role of macrophages phenotypes in the activation of resolution pathways within human granulosa cells

BACKGROUND

Inflammatory state within the ovaries can disrupt normal follicular dynamics, leading to reduced oocyte quality and infertility. How the production of inflammatory mediators generated by macrophages with different gene expression profile (M1 and M2) might activate inflammatory pathways, such as cyclooxygenase-2 (COX-2) and 5-, 12-, and 15-lipoxygenase (LOX), in human granulosa cells (hGCs) remains unclear.

METHODS

In this study, we evaluated how M1 and M2 macrophages found in the ovaries affect the functions of hGCs isolated from women undergoing assisted reproductive technology (ART) and human ovarian granulosa COV434 cells. For this purpose, a model of interaction between hGCs and COV434 cells and conditioned media (CMs) obtained from culture of M0, M1 and M2 macrophages was established. We used real-time PCR and western blotting to detect the expression of COX-2 and 5-, 12-, and 15-LOX as biomarkers of oocyte competence.

RESULTS

Our data showed that M2 macrophages with anti-inflammatory characteristics were able to significantly increase the expression of COX-2 in hGCs. We also demonstrated that M1 macrophages with pro-inflammatory characteristics were able to significantly increase the expression of 12-LOX in hGCs. However, there was no observed expression of 5-LOX and no significant alteration in the expression of 15-LOX in hGCs. Regarding COV434 cells, we found that CM from M2 macrophage resulted in an increase in COX-2, 5-LOX and 15-LOX mRNA and protein levels. No expression of 12-LOX by COV434 cells was observed when exposed to CMs from M1 and M2 macrophages.

CONCLUSIONS

Our research indicated that the production of pro-resolving mediators by hGCs can, at least in part, reverse the physiological inflammation present in the ovaries.

Advanced Respiratory Models for Hazard Assessment of Nanomaterials—Performance of Mono-, Co- and Tricultures

Advanced in vitro models are needed to support next-generation risk assessment (NGRA), moving from hazard assessment based mainly on animal studies to the application of new alternative methods (NAMs). Advanced models must be tested for hazard assessment of nanomaterials (NMs). The aim of this study was to perform an interlaboratory trial across two laboratories to test the robustness of and optimize a 3D lung model of human epithelial A549 cells cultivated at the air–liquid interface (ALI). Potential change in sensitivity in hazard identification when adding complexity, going from monocultures to co- and tricultures, was tested by including human endothelial cells EA.hy926 and differentiated monocytes dTHP-1. All models were exposed to NM-300K in an aerosol exposure system (VITROCELL^® cloud-chamber). Cyto- and genotoxicity were measured by AlamarBlue and comet assay. Cellular uptake was investigated with transmission electron microscopy. The models were characterized by confocal microscopy and barrier function tested. We demonstrated that this advanced lung model is applicable for hazard assessment of NMs. The results point to a change in sensitivity of the model by adding complexity and to the importance of detailed protocols for robustness and reproducibility of advanced in vitro models.

Oxytocin: An Old Hormone, A Novel Psychotropic Drug And Possible Use In Treating Psychiatric Disorders

BACKGROUND

Oxytocin is a nonapeptide synthesized in the paraventricular and supraoptic nuclei of the hypothalamus. Historically, this molecule has been involved as a key factor in the formation of infant attachment, maternal behavior and pair bonding and, more generally, in linking social signals with cognition, behaviors and reward. In the last decades, the whole oxytocin system has gained a growing interest as it was proposed to be implicated in etiopathogenesis of several neurodevelopmental and neuropsychiatric disorders.

METHODS

With the main goal of an in-depth understanding of the oxytocin role in the regulation of different functions and complex behaviors as well as its intriguing implications in different neuropsychiatric disorders, we performed a critical review of the current state of art. We carried out this work through PubMed database up to June 2021 with the search terms: 1) "oxytocin and neuropsychiatric disorders"; 2) "oxytocin and neurodevelopmental disorders"; 3) "oxytocin and anorexia"; 4) "oxytocin and eating disorders"; 5) "oxytocin and obsessive-compulsive disorder"; 6) "oxytocin and schizophrenia"; 7) "oxytocin and depression"; 8) "oxytocin and bipolar disorder"; 9) "oxytocin and psychosis"; 10) "oxytocin and anxiety"; 11) "oxytocin and personality disorder"; 12) "oxytocin and PTSD".

RESULTS

Biological, genetic, and epigenetic studies highlighted quality and quantity modifications in the expression of oxytocin peptide or in oxytocin receptor isoforms. These alterations would seem to be correlated with a higher risk of presenting several neuropsychiatric disorders belonging to different psychopathological spectra. Collaterally, the exogenous oxytocin administration has shown to ameliorate many neuropsychiatric clinical conditions.

CONCLUSION

Finally, we briefly analyzed the potential pharmacological use of oxytocin in patient with severe symptomatic SARS-CoV-2 infection due to its anti-inflammatory, anti-oxidative and immunoregulatory properties.

Determination of drug efficacy to dissolve cobalt oxide particles in cellular models: Towards a therapeutic approach to decrease pulmonary retention

Following accidental inhalation of radioactive cobalt particles, the poorly soluble and highly radioactive Co₃O₄ particles are retained for long periods in lungs. To decrease their retention time is of crucial importance to minimize radiation-induced damage. As dissolved cobalt is quickly transferred to blood and eliminated by urinary excretion, enhancing the dissolution of particles would favor ⁶⁰Co elimination. We evaluated the ability of ascorbic acid alone or associated with the chelating agents DTPA¹, DFOB² or EDTA³ to enhance dissolution of cobalt particles after macrophage engulfment, and the drug effects on the translocation of the soluble species CoCl₂ through an epithelial barrier. We exposed differentiated THP-1 macrophage-like cells and Calu-3 lung epithelial cells cultured in a bicameral system to cobalt and selected molecules up to 7 days. DTPA, the recommended treatment in man, used alone showed no effect, whereas ascorbic acid significantly increased dissolution of Co₃O₄ particles. An additional efficacy in intracellular particles dissolution was observed for combinations of ascorbic acid with DTPA and EDTA. Except for DFOB, treatments did not significantly modify translocation of dissolved cobalt across the epithelial lung barrier. Our study provides new insights for decorporating strategies following radioactive cobalt particle intake.

Gene Expression Profiling of Mono- and Co-Culture Models of the Respiratory Tract Exposed to Crystalline Quartz under Submerged and Air-Liquid Interface Conditions

In vitro lung cell models like air-liquid interface (ALI) and 3D cell cultures have advanced greatly in recent years, being especially valuable for testing advanced materials (e.g., nanomaterials, fibrous substances) when considering inhalative exposure. Within this study, we established submerged and ALI cell culture models utilizing A549 cells as mono-cultures and co-cultures with differentiated THP-1 (dTHP-1), as well as mono-cultures of dTHP-1. After ALI and submerged exposures towards α-quartz particles (Min-U-Sil5), with depositions ranging from 15 to 60 µg/cm2, comparison was made with respect to their transcriptional cellular responses employing high-throughput RT-qPCR. A significant dose- and time-dependent induction of genes coding for inflammatory proteins, e.g., IL-1A, IL-1B, IL-6, IL-8, and CCL22, as well as genes associated with oxidative stress response such as SOD2, was observed, even more pronounced in co-cultures. Changes in the expression of similar genes were more pronounced under submerged conditions when compared to ALI exposure in the case of A549 mono-cultures. Hereby, the activation of the NF-κB signaling pathway and the NLRP3 inflammasome seem to play an important role. Regarding genotoxicity, neither DNA strand breaks in ALI cultivated cells nor a transcriptional response to DNA damage were observed. Altogether, the toxicological responses depended considerably on the cell culture model and exposure scenario, relevant to be considered to improve toxicological risk assessment.

Phagocytosis of Erythrocytes from Gaucher Patients Induces Phenotypic Modifications in Macrophages, Driving Them toward Gaucher Cells

Gaucher disease (GD) is caused by glucocerebrosidase deficiency leading to the accumulation of sphingolipids in macrophages named “Gaucher’s Cells”. These cells are characterized by deregulated expression of cell surface markers, abnormal secretion of inflammatory cytokines, and iron sequestration. These cells are known to infiltrate tissues resulting in hematological manifestations, splenomegaly, and bone diseases. We have already demonstrated that Gaucher red blood cells exhibit altered properties suggesting their key role in GD clinical manifestations. We hypothesized that Gaucher’s erythrocytes could be prone to premature destruction by macrophages contributing to the formation of altered macrophages and Gaucher-like cells. We conducted in vitro experiments of erythrophagocytosis using erythrocytes from Gaucher’s patients or healthy donors. Our results showed an enhanced erythrophagocytosis of Gaucher red blood cells compared to healthy red blood cells, which is related to erythrocyte sphingolipids overload and reduced deformability. Importantly, we showed elevated expression of the antigen-presenting molecules CD1d and MHC-II and of the iron-regulator hepcidin in macrophages, as well as enhanced secretion of the pro-inflammatory cytokine IL-1β after phagocytosis of GD erythrocytes. These results strongly suggested that erythrophagocytosis in GD contribute to phenotypic modifications in macrophages. This present study shows that erythrocytes-macrophages interactions may be crucial in GD pathophysiology and pathogenesis.

Immune Response of the Monocytic Cell Line THP-1 Against Six Aeromonas spp

Aeromonas are autochthonous bacteria of aquatic environments that are considered to be emerging pathogens to humans, producing diarrhea, bacteremia, and wound infections. Genetic identification shows that 95.4% of the strains associated with clinical cases correspond to the species Aeromonas caviae (37.26%), Aeromonas dhakensis (23.49%), Aeromonas veronii (21.54%), and Aeromonas hydrophila (13.07%). However, few studies have investigated the human immune response against some Aeromonas spp. such as A. hydrophila, Aeromonas salmonicida, and A. veronii. The present study aimed to increase the knowledge about the innate human immune response against six Aeromonas species, using, for the first time, an in vitro infection model with the monocytic human cell line THP-1, and to evaluate the intracellular survival, the cell damage, and the expression of 11 immune-related genes (TLR4, TNF-α, CCL2, CCL20, JUN, RELA, BAX, TP53, CASP3, NLRP3, and IL-1β). Transcriptional analysis showed an upregulated expression of a variety of the monocytic immune-related genes, with a variable response depending upon the Aeromonas species. The species that produced the highest cell damage, independently of the strain origin, coincidentally induced a higher expression of immune-related genes and corresponded to the more prevalent clinical species A. dhakensis, A. veronii, and A. caviae. Additionally, monocytic cells showed an overexpression of the apoptotic and pyroptotic genes involved in cell death after A. dhakensis, A. caviae, and Aeromonas media infection. However, the apoptosis route seemed to be the only way of producing cell damage and death in the case of the species Aeromonas piscicola and Aeromonas jandaei, while A. veronii apparently only used the pyroptosis route.