Cells Of Monocyte-macrophage Lineage Research Articles

Investigating the pro-inflammatory differentiation of macrophages with bacterial ghosts in potential infection control.

In the complex realm of bacterial infections, particularly those caused by Staphylococcus aureus (S. aureus), macrophages play a pivotal role in orchestrating the immune response. During the initial stages of infection, the monocytes give rise to macrophages with a pro-inflammatory (M1 type) behaviour, engulfing and neutralizing the invading pathogens. However, under the sustained influence of S. aureus infection, monocytes can undergo a transition into an anti-inflammatory M2 state (pro-infection) rather than the M1 state (anti-infection), thereby compromising effective infection control. Therefore, it is necessary to develop a strategy that would preserve the pro-inflammatory functions of macrophages, in a safe and controlled manner. For this, we focused on harnessing the potential of S. aureus-derived ghost cells (GCs) which are non-live empty envelopes of bacterial cells, but with the antigenic determinants intact. Through a unique Lugol's-iodine treatment, we generated GCs and characterization of these GCs using gel electrophoresis, FTIR, flow cytometry, TEM, and SEM confirmed their structural integrity. Following this, we assessed the extend of cellular association of the GCs with RAW267.4 macrophages, and observed an immediate interaction between the two, as evident from the flowcytometry and microscopy studies. We then performed macrophage polarisation on a human monocyte-macrophage model cell line, THP-1. Our findings revealed that GCs effectively activated macrophages, and promoted a pro-inflammatory polarisation with the expression of M1 differentiation markers (CD86, TNFα, IL-1β, IL-6, IL-12) evaluated through both qPCR and ELISA. Interestingly an intermediary expression of M2 markers viz., CD206 and IL-10 was also observed, but was overruled by the enhanced expression of M1 markers at a later time point. Overall, our study introduces a novel approach utilizing GCs to guide naïve macrophages towards M1 subtypes, thereby potentiating immune responses during microbial infections. This innovative strategy can modulate macrophage function, ultimately improving outcomes in S. aureus infections and beyond.

Pigs lacking the SRCR5 domain of CD163 protein demonstrate heritable resistance to the PRRS virus and no changes in animal performance from birth to maturity.

Porcine reproductive and respiratory syndrome (PRRS) is one of the world's most persistent viral pig diseases, with a significant economic impact on the pig industry. PRRS affects pigs of all ages, causing late-term abortions and stillbirths in sows, respiratory disease in piglets, and increased susceptibility to secondary bacterial infection with a high mortality rate. PRRS disease is caused by a positive single-stranded RNA PRRS virus (PRRSV), which has a narrow host-cell tropism limited to monocyte-macrophage lineage cells. Several studies demonstrated that the removal of CD163 protein or, as a minimum, its scavenger receptor cysteine-rich domain 5 (SRCR5) precludes the viral genome release, conferring resistance to PRRSV in live animals. Today, very limited information exists about the impact of such edits on animal performance from birth to maturity in pigs. Using CRISPR-Cas9 with dual-guide RNAs and non-homologous end joining (NHEJ), first-generation (E0) pigs were produced with a deletion of exon 7 in the CD163 gene. The selected pigs were bred to produce the next three generations of pigs to establish multiple lines of pigs homozygous for the edited allele, thereby confirming that the CD163 gene with removed exon 7 was stable during multiple breeding cycles. The pigs were evaluated relative to non-edited pigs from birth to maturity, including any potential changes in meat composition and resistance to PRRSV. This study demonstrates that removing the SRCR5 domain from the CD163 protein confers resistance to PRRSV and, relative to unedited pigs, resulted in no detected differences in meat composition and no changes in the growth rate, health, and ability to farrow. Together, these results support the targeted use of gene editing in livestock animals to address significant diseases without adversely impacting the health and well-being of the animals or the food products derived from them.

The role of 27-hydroxycholesterol in meta-inflammation.

27-Hydroxycholesterol (27OHChol), a prominent cholesterol metabolite present in the bloodstream and peripheral tissues, is a kind of immune oxysterol that elicits immune response. Recent research indicates the involvement of 27OHChol in metabolic inflammation (meta-inflammation) characterized by chronic responses associated with metabolic irregularities. 27OHChol activates monocytic cells such that they secrete pro-inflammatory cytokines and chemokines, and increase the expression of cell surface molecules such as pattern-recognition receptors that play key roles in immune cell-cell communication and sensing metabolism-associated danger signals. Levels of 27OHChol increase when cholesterol metabolism is disrupted, and the resulting inflammatory responses can contribute to the development and complications of metabolic syndrome, including obesity, insulin resistance, and cardiovascular diseases. Since 27OHChol can induce chronic immune response by activating monocyte-macrophage lineage cells that play a crucial role in meta-inflammation, it is essential to understand the 27OHChol-induced inflammatory responses to unravel the roles and mechanisms of action of this cholesterol metabolite in chronic metabolic disorders.

Porcine β-Defensin 114: Creating a Dichotomous Response to Inflammation.

The immunity-related functions of defensins seem to be dependent on environmental stimuli, the cell type, and the concentration of peptides. However, the function and mechanism of porcine β-defensin 114 (pBD114) in regulating the inflammatory response to macrophages are unclear. Therefore, the modulatory effects of porcine pBD114 on the inflammatory response were investigated by treating the mouse monocyte macrophage cell line RAW264.7 with different concentrations of pBD114 with or without lipopolysaccharide (LPS). RNA-seq analysis was performed to investigate the mechanisms underlying pBD114's regulation of inflammatory responses in macrophages. In addition, the inflammatory response-modulating effects of pBD114 were also further verified with a mouse assay. The results showed that 100 μg/mL of pBD114 significantly promoted the secretion of TNF-α and IL-10 in RAW264.7. However, the LPS-induced increase in TNFα in the RAW264.7 cell cultures was significantly decreased with 10 μg/mL of pBD114. These results suggest that pBD114 can exhibit pro-inflammatory activities under normal physiological conditions with 100 μg/mL of pBD114, and anti-inflammatory activities during an excessive inflammatory response with 10 μg/mL of pBD114. RNA-seq analysis was performed to gain further insights into the effects of pBD114 on the inflammatory response. Among the pBD114-promoting RAW264.7 pro-inflammatory responses, pBD114 significantly up-regulated 1170 genes and down-regulated 724 genes. KEGG enrichment showed that the differentially expressed genes (DEGs) were significantly enriched in the immune- and signal-transduction-related signaling pathways. Protein-Protein Interaction (PPI) and key driver analysis (KDA) analyses revealed that Bcl10 and Bcl3 were the key genes. In addition, pBD114 significantly up-regulated 12 genes and down-regulated 38 genes in the anti-inflammatory response. KEGG enrichment analysis revealed that the DEGs were mainly enriched in the "Cytokine-cytokine receptor interaction" signaling pathway, and PPI and KDA analyses showed that Stat1 and Csf2 were the key genes. The results of qRT-PCR verified those of RNA-seq. In vivo mouse tests also confirmed the pro- or anti-inflammatory activities of pBD114. Although the inflammatory response is a rapid and complex physiological reaction to noxious stimuli, this study found that pBD114 plays an essential role mainly by acting on the genes related to immunity, signal transduction, signaling molecules, and interactions. In conclusion, this study provides a certain theoretical basis for the research and application of defensins.

The non-pathogenic protozoon Leishmania tarentolae interferes with the activation of NLRP3 inflammasome in human cells: new perspectives in the control of inflammation.

Innate immune responses against infectious agents can act as triggers of inflammatory diseases. On the other hand, various pathogens have developed mechanisms for the evasion of the immune response, based on an inhibition of innate immunity and inflammatory responses. Inflammatory diseases could thus be controlled through the administration of pathogens or pathogen-derived molecules, capable of interfering with the mechanisms at the basis of inflammation. In this framework, the NLRP3 inflammasome is an important component in innate antimicrobial responses and a major player in the inflammatory disease. Parasites of the genus Leishmania are master manipulators of innate immune mechanisms, and different species have been shown to inhibit inflammasome formation. However, the exploitation of pathogenic Leishmania species as blockers of NLRP3-based inflammatory diseases poses safety concerns. To circumvent safety issues associated with pathogenic parasites, we focused on Leishmania tarentolae, a species of Leishmania that is not infectious to humans. Because NLRP3 typically develops in macrophages, in response to the detection and engulfment microorganisms, we performed our experiments on a monocyte-macrophage cell line (THP-1), either wild type or knockout for ASC, a key component of NLRP3 formation, with determination of cytokines and other markers of inflammation. L. tarentolae was shown to possess the capability of dampening the formation of NLRP3 inflammasome and the consequent expression of pro-inflammatory molecules, with minor differences compared to effects of pathogenic Leishmania species. The non-pathogenic L. tarentolae appears a promising pro-biotic microbe with anti-inflammatory properties or a source of immune modulating cellular fractions or molecules, capable of interfering with the formation of the NLRP3 inflammasome.

Molecular and clinical characterization of ANG expression in gliomas and its association with tumor-related immune response.

Angiogenin (ANG) has been widely reported as a crucial molecular regulator in multiple malignancies. However, its role in gliomagenesis remains unclear. This study aimed to investigate the molecular and clinical characterization of ANG expression at transcriptome level and the association with glioma-related immune response. A total of 301 glioma samples with mRNA microarray data (CGGA301) was obtained from the official website of CGGA project for yielding preliminary results, followed by validation in two independent RNAseq datasets, including TCGA with 697 samples and CGGA325 with 325 patients. Moreover, CGGA single-cell RNAseq (scRNAseq) data were analyzed to identify differential and dynamic ANG expression in different cells. Immunohistochemistry was performed to evaluate ANG protein expression across different WHO grades in a tissue microarray (TMA). Figure generation and statistical analysis were conducted using R software. ANG expression was associated with clinical features, malignant phenotypes, and genomic alterations. Based on significantly correlated genes of ANG, subsequent gene ontology (GO) and gene set enrichment analysis (GSEA) concordantly pointed to the significant association of ANG in immune-related biological processes. Moreover, ANG showed robust correlations with canonical immune checkpoint molecules, including PD1 signaling, CTLA4, TIM3, and B7H3. Gene sets variation analysis (GSVA) found that ANG was particularly associated with activities of macrophages and antigen presentation cells (APCs) in both LGG and GBM across different datasets. Furthermore, the higher-ANG milieu seemed to recruit monocyte-macrophage lineage and dendritic cells into the glioma microenvironment. According to scRNAseq analysis, ANG was mainly expressed by neoplastic cells and tumor-associated macrophages (TAMs) and was correlated with the initiation and progression of tumor cells and the polarization of TAMs. Finally, Kaplan-Meier plots demonstrated that higher expression of ANG was significantly correlated with shorter survival in gliomas. Cox regression analysis further confirmed ANG as an independent predictor of prognosis for gliomas of all three datasets. ANG is significantly correlated with a range of malignant and aggressive characteristics in gliomas and reveals considerable prognostic value for glioma patients. ANG seems to be primarily associated with immune activities of macrophages and APCs in gliomas. Furthermore, ANG is mainly expressed in neoplastic cells and TAMs and is involved in the initiation and progression of neoplastic cells as well as macrophage polarization.

The rs2228145 Variant of the Interleukin-6 Receptor (IL-6R) Gene Impacts on In Vitro Cellular Responses to SARS-CoV-2 VOC B1.1.7 Recombinant Spike Protein

Given the variability in inflammatory responses to SARS-CoV-2 infection observed within human populations, we aimed to develop an in vitro model system (based on monocyte-macrophages, a key relevant cell type) that could yield insights regarding the impact of rs2228145, a clinically relevant polymorphism within the coding region of a key inflammatory gene in the body’s response to SARS-CoV-2 infection: the interleukin-6 receptor (IL-6R) gene. Three monocyte-macrophage cell-lines (U937, THP-1, MM6) were shown to exhibit AA, AC and CC rs2228145 genotypes, respectively, and to exhibit an MM6 > THP-1 > U937 pattern regarding basal levels of soluble IL-6R (sIL-6R) release. Similar MM6 > THP-1 > U937 patterns were seen regarding the extents to which (i) circulating levels of the IL-6/sIL-6R ‘active complex’ increased and (ii) phosphorylation of the downstream transcription-factor STAT3 occurred, following treatment with SARS-CoV-2 spike protein (SP). Moreover, a blocking antibody for the ACE-2 entry receptor for SARS-CoV-2 suppressed effects (i) and (ii), suggesting that interaction between SP and ACE-2 is the initial event that triggers IL-6/IL-6R signalling in our system. Production of IL-8 occurred to greater extents in A549 lung epithelial cells treated with tissue-culture supernatants from SP-treated MM6 cultures than SP-treated THP-1 or U937 cultures. Our data indicate that the rs2228145 genotype significantly impacts upon SP-associated IL-6/sIL-6R signalling in vitro, suggesting that it may influence in vivo risk of developing severe COVID-19 and/or long-COVID symptoms following infection by SARS-CoV-2. Thus, the rs2228145 genotype may have potential as a biomarker that differentiates between patients at risk of developing severe and/or prolonged symptoms following infection by SARS-CoV-2 and those who are at less risk.

Phenotypic profle of monocyte-macrophage lineage cells as a function of respiratory epithelium status

The mechanism of the relationship between pretumor changes in the bronchial respiratory epithelium and the risk of progression of non-small cell lung cancer (NSCLC) remains unclear. It has been suggested that the relationship between reactive changes in the bronchial mucosa and NSCLC progression may be caused by the functional status of monocytic-macrophage cells as important participants in infammation, which determines both the risk of premalignant changes in the epithelium and malignant progression. The purpose of the study was to investigate the phenotypic profle of peripheral blood monocytes and macrophages induced from monocytes in vitro depending on the state of respiratory epithelium in NSCLC patients. Material and Methods. The study included 39 patients with newly diagnosed NSCLC. Based on the morphological examination of small bronchi taken at the distance of 3–5 cm from the tumor, patients were divided into the following groups depending on the type of pretumor changes: no pretumor changes (n=6), isolated basal cell hyperplasia (BCH) (n=13), combination of BCH and squamous metaplasia (SM) (n=3), combination of unchanged epithelium and focal BCH (n=17). The phenotypic features of peripheral blood monocytes and in vitro-induced macrophages were assessed before treatment using fow cytometry. Results. The state of the respiratory epithelium in NSCLC patients prior to the start of anticancer treatment was associated with the phenotypic features of peripheral blood monocytes, but not with the profle of macrophages induced from them. Distortion of the response of induced macrophages to the polarizing stimuli was observed in NSCLC patients: the cultured cells responded to both M1 and M2 inducers (LPS and IL-4, respectively) with a phenotype shift to M2, while the CD206 marker expression varied depending on the presence and type of pretumor changes. Conclusion. The phenotypic profle of peripheral blood monocytes was associated with the state of the respiratory epithelium in NSCLC patients before anti-tumor treatment, but not with the phenotypic features of induced macrophages.

Increased Osteoclastogenesis in Absence of TG2 Is Reversed by Transglutaminase Inhibition-Evidence for the Role for TG1 in Osteoclast Formation.

Osteoclasts are multinucleated, bone-resorbing giant cells derived from monocyte-macrophage cell lines. Increased bone resorption results in loss of bone mass and osteoporosis. Osteoclast and bone marrow macrophages have been shown to express three TG enzymes (TG2, Factor XIII-A, and TG1) and TG activity to regulate osteoclast differentiation from bone marrow macrophages in vitro. In vivo and in vitro studies have demonstrated that the deletion of TG2 causes increased osteoclastogenesis and a significant loss of bone mass in mice (Tgm2-/- mice). Here, we confirm that TG2 deficiency results in increased osteoclastogenesis in vitro and show that this increase can be reversed by a TG inhibitor, NC9, suggesting that other TGs are responsible for driving osteoclastogenesis in the absence of TG2. An assessment of total TG activity with 5-(biotinamido)-pentylamine, as well as TG1 and FXIII-A activities using TG-specific Hitomi peptides (bK5 and bF11) in Tgm2-/- bone marrow flushes, bone marrow macrophages, and osteoclasts, showed a significant increase in total TG activity and TG1 activity. Factor XIII-A activity was unchanged. Aspartate proteases, such as cathepsins, are involved in the degradation of organic bone matrix and can be produced by osteoclasts. Moreover, Cathepsin D was shown in previous work to be increased in TG2-null cells and is known to activate TG1. We show that Pepstatin A, an aspartate protease inhibitor, blocks osteoclastogenesis in wild-type and Tgm2-/- cells and decreases TG1 activity in Tgm2-/- osteoclasts. Cathepsin D protein levels were unaltered in Tgm2-/-cells and its activity moderately but significantly increased. Tgm2-/- and Tgm2+/+ bone marrow macrophages and osteoclasts also expressed Cathepsin E, and Renin of the aspartate protease family, suggesting their potential involvement in this process. Our study brings further support to the observation that TGs are significant regulators of osteoclastogenesis and that the absence of TG2 can cause increased activity of other TGs, such as TG1.

SOLUBLE SERUM CD163 (SCD163) LEVELS IS A MARKER OF DISEASE ACTIVITY IN LYMPHOPLASMACYTIC LYMPHOMA (LPL). PRELIMINARY RESULTS

Introduction: sCD163 is secreted by monocyte-macrophage lineage cells, including Tumor-Αssociated Μacrophages (TAM) that participate in neoplastic and immune regulation. LPL is a lymphoproliferative neoplastic disorder, the spectrum of which comprises Waldenstrom’s macroglobulinaemia (WM) in its symptomatic, asymptomatic and precursor forms as well as non-secreting or IgG/IgA-secreting cases. sCD163 eventual role in LPL has not been investigated so far. Aims: To determine sCD163 levels in a series of LPL patients at diagnosis and evaluate possible correlations with disease activity. Patients and Methods: Twenty-nine patients were studied (24 WM of whose 5 asymptomatic, 2 IgM-MGUS with related peripheral neuropathy and 3 LPL) after their informed consent. Clinical and routine laboratory data were collected. Median time to treatment (TTT) was 11 months and median overall survival (OS) 128 months. Serum sCD163 was tested in frozen sera of patients collected at diagnosis and in 15 healthy individuals (HI). Measurements were performed by ELISA (Duo-Set R&D Quantiquine) according to the manufacturer’s instructions. Statistical analysis was performed with the SPSS v.26 software and survival curves were drawn by the Kaplan-Mayer methods and compared by the log-rank test. Results: Median serum sCD163 was 109000 pg/mL and 117952 pg/mL in patients and HI respectively. Time to treatment was significantly shorter in patients with serum sCD163 values above median (p = 0.004), compared to the others (figure). In addition sCD163 levels were correlated with platelet number, the presence of lymphadenopathy and IgM in WM-only patients. Keywords: diagnostic and prognostic biomarkers, indolent non-Hodgkin lymphoma, tumor biology and heterogeneity No conflicts of interests pertinent to the abstract.

INCREASED SOLUBLE SERUM CD163 (SCD163) LEVELS PREDICT A SHORT DISEASE FREE SURVIVAL IN DIFFUSE LARGE B‐CELL LYMPHOMA (DLBCL)

Introduction: Monocyte counts were found of prognostic significance in DLBCL, implying the possible contribution of monocyte-macrophage lineage cells in disease pathogenesis. These cells secrete among others sCD163, the role of which has not been investigated yet. Aims: To study eventual correlation of serum sCD163 levels with prognosis in DLBCL. Patients and Methods: Twenty-six DLBCL patients were studied with a median follow-up time of 21 months (2–138). Ten were diagnosed in early stages (1 and 2) while the resting majority was in advanced stages (3 and 4). Six patients (23%) relapsed early during disease course. Seven patients succumbed to their disease and other 3 from other causes. SerumCD163 measurements were performed by ELISA (Duo-Set R&D Quantiquine) according to the manufacturer’s instructions in frozen sera kept at diagnosis. The SPSS v.26 software was used for statistical analysis and survival curves were drawn by Kaplan-Mayer method and compared by the log-rank test. Results: Serum sCD163 levels ranged from 34072 to 164912 pg/mL (median 134672 pg/mL) in patients and from 104420 to >140000 pg/mL (median 117952 pg/mL) in 15 healthy individuals. Patients with serum sCD163 levels above median had a higher probability of relapse and a shorter disease free survival (p = 0.004), compared to the others (figure). Overall survival was not affected by sCD163 levels. Keywords: aggressive B-cell non-Hodgkin lymphoma, diagnostic and prognostic biomarkers, targeting the tumor microenvironment No conflicts of interests pertinent to the abstract.

In‐vitro toxicity of cyclophosphamide and etoposide intermediates/metabolites produced by three white rot fungi

AbstractAim of the present study is to determine the in‐vitro cell cytotoxic effect of native and transformed cancer drugs (cyclophosphamide and etoposide) using three different white rot fungi (Ganoderma lucidum, Phanerochaete chrysosporium and Trametes versicolor). At 3, 6, 9, 12 and 15 days, experiments were done on a mouse monocyte macrophage cell line (Raw 264.7). After biodegradation, the altered compounds were found to be harmful to the Raw 264.7 cells. The maximal cytotoxicity of cyclophosphamide transformed products (TPs) were determined to be 2.4%, 7.3% and 7% respectively, against G. lucidum, P. chrysosporium and T. versicolor, respectively. With G. lucidum, P. chrysosporium and T. versicolor, the etoposide toxicity was 1.5%, 8% and 2.7% respectively. P. chrysosporium‐mediated biodegradation resulted in the maximum toxicity, at 8%, on the 12th day for etoposide and 7.3% on the 3rd day for cyclophosphamide. After biodegradation by fungi, the toxicity of these two anticancer agents was reduced in the form of metabolites, but each fungus showed unique capacity for toxicity removal.

IRAK4 inhibition: an effective strategy for immunomodulating peri-implant osseointegration via reciprocally-shifted polarization in the monocyte-macrophage lineage cells

BackgroundThe biomaterial integration depends on its interaction with the host immune system. Monocyte-macrophage lineage cells are immediately recruited to the implant site, polarized into different phenotypes, and fused into multinucleated cells, thus playing roles in tissue regeneration. IL-1R-associated kinase 4 (IRAK4) inhibition was reported to antagonize inflammatory osteolysis and regulate osteoclasts and foreign body giant cells (FBGCs), which may be a potential target in implant osseointegration.MethodsIn in-vitro experiments, we established simulated physiological and inflammatory circumstances in which bone-marrow-derived macrophages were cultured on sand-blasted and acid-etched (SLA) titanium surfaces to evaluate the induced macrophage polarization, multinucleated cells formation, and biological behaviors in the presence or absence of IRAK4i. Then, bone marrow stromal stem cells (BMSCs) were cultured in the conditioned media collected from the aforementioned induced osteoclasts or FBGCs cultures to clarify the indirect coupling effect of multinucleated cells on BMSCs. We further established a rat implantation model, which integrates IRAK4i treatment with implant placement, to verify the positive effect of IRAK4 inhibition on the macrophage polarization, osteoclast differentiation, and ultimately the early peri-implant osseointegration in vivo.ResultsUnder inflammatory conditions, by transforming the monocyte-macrophage lineage cells from M1 to M2, IRAK4i treatment could down-regulate the formation and activity of osteoclast and relieve the inhibition of FBGC generation, thus promoting osteogenic differentiation in BMSCs and improve the osseointegration.ConclusionThis study may improve our understanding of the function of multinucleated cells and offer IRAK4i as a therapeutic strategy to improve early implant osseointegration and help to eliminate the initial implant failure.

High-Throughput CAMP Assay (HiTCA): A Novel Tool for Evaluating the Vitamin D-Dependent Antimicrobial Response.

Vitamin D is known to modulate human immune responses, and vitamin D deficiency is associated with increased susceptibility to infection. However, what constitutes sufficient levels or whether vitamin D is useful as an adjuvant therapeutic is debated, much in part because of inadequate elucidation of mechanisms underlying vitamin D's immune modulatory function. Cathelicidin antimicrobial peptide (CAMP) has potent broad-spectrum activity, and the CAMP gene is regulated in human innate immune cells by active 1,25(OH)2D3, a product of hydroxylation of inactive 25(OH)D3 by CYP27B1-hydroxylase. We developed a CRISPR/Cas9-edited human monocyte-macrophage cell line containing the mCherry fluorescent reporter gene at the 3' end of the endogenous CAMP gene. The High Throughput CAMP Assay (HiTCA) developed here is a novel tool for evaluating CAMP expression in a stable cell line that is scalable for a high-throughput workflow. Application of HiTCA to serum samples from a small number of human donors (n = 10) showed individual differences in CAMP induction that were not fully accounted for by the serum vitamin D metabolite status of the host. As such, HiTCA may be a useful tool that can advance our understanding of the human vitamin D-dependent antimicrobial response, which is being increasingly appreciated for its complexity.

Cathepsin B/NLRP3/GSDMD axis-mediated macrophage pyroptosis induces inflammation and fibrosis in systemic sclerosis

BackgroundPyroptosis is a newly discovered type of programmed cell death associated with inflammatory and fibrotic diseases. Macrophages play an important role in inducing early immune inflammation in systemic sclerosis (SSc). ObjectiveTo investigate the effect of macrophages pyroptosis on fibrosis of SSc. MethodsPyroptosis/inflammatory markers in serum and skin of SSc patients were detected. Bleomycin (BLM) was subcutaneously injected to establish SSc mouse model. The levels of pyroptosis markers, dermal thickness and collagen deposition in skin were assessed before and after the administration of pyroptosis inhibitors, including MCC950, Disulfiram and necrosulfonamide (NSA). Human-derived monocyte-macrophage cell line (THP-1) or mouse bone marrow-derived macrophages (BMDMs) were primed with lipopolysaccharide (LPS) and stimulated by silicon dioxide (SiO2) to induce cell pyroptosis. Fibroblasts from patients with SSc were co-cultured with pyroptotic THP-1 cells, and the collagen production was assessed. ResultsPyroptotic/inflammatory proteins, including NLRP3, cleaved-Caspase (CASP)1, GSDMD-N terminal and IL-18 were increased in the serum, and ASC aggregation and GSDMD were elevated in macrophages in the skin of SSc patients. SSc mice showed increased pyroptosis markers, dermal thickness and collagen deposition in skins, which were alleviated by MCC950, Disulfiram and NSA. Pyroptosis of THP-1 cells and BMDMs was induced by LPS/SiO2, and it was reduced by the inhibitors of Cathepsin B, NLRP3, CASP1 and GSDMD. Co-culture with pyroptotic THP-1 cells increased the fibrotic proteins in fibroblasts, which were alleviated by pyroptosis inhibitors. ConclusionsSSc patients and BLM-induced mouse model presented increased pyroptosis. LPS/SiO2-induced macrophage pyroptosis promoted fibrosis of SSc through Cathepsin B/NLRP3/GSDMD pathway.

Epithelial sodium channels in macrophage migration and polarization: role of proinflammatory cytokines TNFα and IFNγ.

Migration of monocytes-macrophages plays an important role in phagocytosis of pathogens and cellular debris in a variety of pathophysiological conditions. Although epithelial Na+ channels (ENaCs) are required for normal migratory responses in other cell types, their role in macrophage migration signaling is unknown. To address this possibility, we determined whether ENaC message is present in several peripheral blood monocyte cell populations and tissue-resident macrophages in healthy humans using the Human Protein Atlas database (www.proteinatlas.org) and the mouse monocyte cell line RAW 264.7 using RT-PCR. We then determined that selective ENaC inhibition with amiloride inhibited chemotactic migration (∼50%), but not phagocytosis, of the mouse monocyte-macrophage cell line RAW 264.7. Furthermore, we generated a cell line stably expressing an NH2-terminal truncated αENaC to interrupt normal channel trafficking and found it suppressed migration. Prolonged exposure (48 h) of RAW 264.7 cells to proinflammatory cytokines interferon γ (IFNγ) and/or tumor necrosis factor α (TNFα) inhibited RAW 264.7 migration and abolished the amiloride (1 µM)-sensitive component of migration, a finding consistent with ENaC downregulation. To determine if proinflammatory cytokines regulate αENaC protein expression, cells were exposed to proinflammatory cytokines IFNγ (10 ng/mL, last 48 h) and TNFα (10 ng/mL, last 24 h). By Western blot analysis, we found whole cell αENaC protein is reduced ≥50%. Immunofluorescence demonstrated heterogeneous αENaC inhibition. Finally, we found that overnight exposure to amiloride stimulated morphological changes and increased polarization marker expression. Our findings suggest that ENaC may be a critical molecule in macrophage migration and polarization.

Knee osteoarthritis phenotypes based on synovial fluid immune cells correlate with clinical outcome trajectories

Knee osteoarthritis (KOA) is a highly heterogeneous disease encompassing a wide range of clinical phenotypes. Phenotypes based on immune cells and protein pattern in synovial fluid (SF) and their relationship to clinical trajectories have not been described. To assess phenotypes based on immune cells and protein pattern of SF in KOA. SF-derived immune cells were investigated in 119 patients with KOA using flow cytometry. Immune-phenotypes (iPhen) were determined by multivariate patient similarity network analysis and related to clinical trajectory (3-6 months post-sampling) along with protein pattern and macrophage chemokine receptors. Four iPhen were detected based on the distribution of T-lymphocytes, monocyte-macrophage lineage cells and activated CD8+ T-lymphocytes. The 'activated' phenotype (n=17) had high T-lymphocytes but low monocyte-macrophage lineage cells and neutrophils, all highly activated, and showed improved symptoms in 70% patients. The 'lymphoid progressive' phenotype (n=31) had high neutrophils, low lymphocytes and monocyte-macrophage lineage cells, low activation and was associated with lower pain levels. The 'myeloid progressive' phenotype (n=35) had high NK and monocyte-macrophage lineage cells but low T-lymphocytes and activation. The 'aggressive' phenotype (n=36) had high lymphocytes, macrophages, NK cells and neutrophils and high activation, and only 39% of patients improved during follow-up. Low CXCR4 and CCR7 expression on macrophages and high CXCL10 in SF were linked to improved clinical trajectory. We identified four immune-phenotypes that were associated with different clinical trajectories in KOA patients. How these phenotypes can be targeted therapeutically deserves further investigation.

Detection of innate immune response modulating impurities (IIRMI) in therapeutic peptides and proteins: Impact of excipients.

Unintended immunogenicity can affect the safety and efficacy of therapeutic proteins and peptides, so accurate assessments of immunogenicity risk can aid in the selection, development, and regulation of biologics. Product- and process- related impurities can act as adjuvants that activate the local or systemic innate immune response increasing the likelihood of product immunogenicity. Thus, assessing whether products have innate immune response modulating impurities (IIRMI) is a key component of immunogenicity risk assessments. Identifying trace levels of individual IIRMI can be difficult and testing individually for all potential impurities is not feasible. Therefore, to mitigate the risk, cell-based assays that use human blood cells or monocyte-macrophage reporter cell lines are being developed to detect minute quantities of impurities capable of eliciting innate immune activation. As these are cell-based assays, there is concern that excipients could blunt the cell responses, masking the presence of immunogenic IIRMI. Here, we explore the impact of frequently used excipients (non-ionic detergents, sugars, amino acids, bulking agents) on the sensitivity of reporter cell lines (THP-1- and RAW-Blue cells) and fresh human blood cells to detect purified TLR agonists as model IIRMI. We show that while excipients do not modulate the innate immune response elicited by TLR agonists in vivo, they can impact on the sensitivity of cell-based IIRMI assays. Reduced sensitivity to detect LPS, FSL-1, and other model IIRMI was also evident when testing 3 different recombinant drug products, product A (a representative mAb), B (a representative growth factor), C (a representative peptide), and their corresponding formulations. These results indicate that product formulations need to be considered when developing and validating cell-based assays for assessing clinically relevant levels of IIRMI in therapeutic proteins. Optimization of reporter cells, culture conditions and drug product concentration appear to be critical to minimize the impact of excipients and attain sensitive and reproducible assays.

CpG Oligodeoxynucleotides Inhibit RANKL-Induced Osteoclast Formation by Upregulating A20 Deubiquitinase in RAW 264.7 Cells.

Objective Activation of toll-like receptor 9 (TLR9) has been proposed to play an inhibitory role in RANKL-induced osteoclastogenesis. A20 deubiquitinase has been found to be related to bone loss. This study investigated the role of CpG oligodeoxynucleotides (CpG-ODNs) through regulation of A20 deubiquitinase in RANKL-induced osteoclast formation. Methods RAW 264.7 cells, a murine monocyte-macrophage cell line, were incubated with or without CpG-ODN in the presence of RANKL. Osteoclast-specific genes and their related signaling molecules were measured by real-time quantitative polymerase chain reaction and Western blot assay. Morphological assessment for osteoclast formation was performed using tartrate-resistant acid phosphatase (TRAP) staining and F-actin ring formation staining. Results RANKL-induced osteoclast-related genes and proteins, c-Fos, NFATc1, TRAP, cathepsin K, and carbonic anhydrase II were significantly inhibited in RAW 264.7 cells stimulated with CpG-ODN. CpG-ODN attenuated TNF receptor-associated factor 6 (TRAF6), p-IκBα, and p-NF-κB expression in RAW 264 cells mediated by RANKL. CpG-ODN increased A20 gene and proteins in time-dependent manner. A20 expression under costimulation with CpG-ODN and RANKL was more decreased than under stimulation with RANKL alone. Cells transfected with A20 siRNA augmented expression of osteoclast-related genes and proteins. Number of TRAP-positive cells transfected with A20 siRNA was higher than those transfected with NC siRNA. A20 expression in cells transfected with IL-1β siRNA in the presence of both RANKL and CpG-ODN was more decreased than those with NC siRNA. Conclusion This study showed that CpG-ODN suppressed RANKL-induced osteoclast formation through regulation of the A20-TRAF6 axis in RAW 264.7 cells.

Isolation of Monocyte-Macrophage Lineage Cells from Rat Bones by Secondary Adherence Method.

With a decrease of bone mineral density, bones are more likely to fracture, thus negatively affecting a patient's quality of life. The growth and development of bones are mainly regulated by osteoblasts and osteoclasts. It has been widely accepted that osteoclasts are derived from bone marrow monocyte-macrophage cells (BMMs). BMMs and other hematopoietic stem cells are located in the bone marrow cavity. Therefore, isolating single stable BMMs from different and heterogeneous cell populations is a huge challenge. Here we present a protocol for the isolation of BMMs from SD rats, called the secondary adherence method. Adherent cells cultured for 24-48 h in primary culture were collected. Flow cytometric analysis showed that approximately 37.94% of the cells were CD11b/c+ (monocyte-macrophage surface antigen). Tartrate resistant acid phosphatase (TRAP) staining and western blot analysis demonstrated that BMMs could differentiate into osteoclasts in vitro. The above findings suggested that the secondary adherence cells could be considered as a suitable cellular model for osteoclast differentiation research.