Modulation Of Macrophages Research Articles

Exosomal communication by metastatic osteosarcoma cells contributes to the modulation of alveolar macrophages to an M2 tumor-promoting phenotype

Abstract Osteosarcoma (OS) metastasizes to the lung and there is a link between tumor-promoting M2 macrophage content and poorer patient survival. Conversely, high M1 content correlates with improved survival. M2 macrophages are immunosuppressive, contribute to tumor progression and metastasis, and can be induced by various stimuli in the tumor microenvironment, including exosomes (Exo). Exo are small 40–150 nm vesicles that are involved in inter-cellular communication, and contribute to tumor progression, increased tumor survival and immune evasion. Because of the link between M2 content and inferior patient survival, we evaluated the effect of Exo from non-metastatic K7 OS cells and the metastatic subline K7M3 on macrophage phenotype and function. Incubating MHS mouse alveolar macrophage cells with K7M3 Exo induced mRNA expression of IL10, TGFB2, IL1rα, and CCL22, (markers of M2 macrophages), and decreased phagocytosis, efferocytosis and macrophage-mediated tumor cell killing. In contrast, Exo from non-metastatic K7 or 3T3 normal fibroblast cells did not inhibit phagocytosis, efferocytosis or macrophage-mediated tumor cell killing. Our data suggest that the Exo from metastatic OS cells can modulate cellular signaling of tumor associated macrophages, thereby promoting the M2 phenotype and inhibiting their phagocytic and cytotoxic abilities. Identifying the factors within Exo from metastatic OS cells and the mechanisms responsible for Exo communication between metastatic OS cells and macrophages could reveal new therapeutic targets and opportunities to improve the treatment of patients with metastatic disease in the lung.

Targeting Delivery of Oligodeoxynucleotides to Macrophages by Mannosylated Cationic Albumin for Immune Stimulation in Cancer Treatment.

To efficiently deliver CpG oligodeoxynucleotides (ODNs) to macrophages for the reversal of cancer-induced immunosuppression, nanoparticles ODN@MCBSA with mannosylated cationic albumin (MCBSA) as a macrophage targeting vector were constructed. Compared with ODN@CBSA with cationic albumin (CBSA) as a vector, ODN@MCBSA exhibited significantly improved cellular uptake mediated by mannose moieties, resulting in significantly enhanced secretion of proflammatory cytokines including IL-12, IL-6, TNF-α, and iNOS. The modulation of macrophages toward the favorable M1 phenotype was confirmed by the upregulated CD80 expression after being treated by ODN delivery systems. In addition to immune cells, the effects of the ODN delivery system on cancerous HeLa cells were also investigated. The results showed that ODN@MCBSA did not affect the overall tumor cell viability. However, enhanced NF-κB, p-Akt, PIK3R3, Fas, and FasL, as well as upregulated caspases were observed in tumor cells, implying the pleiotropic effects on tumor cells. Our study provides a more in-depth understanding on the immunotherapeutic effects of CpG ODNs and highlights the importance of macrophage targeting delivery to minimize the effects on tumor cells. These results indicate that MCBSA could serve as a promising delivery vector of CpG ODNs to macrophages for cancer immunotherapy.

Human Embryonic Stem Cell-Derived Cardiovascular Progenitors Repair Infarcted Hearts Through Modulation of Macrophages via Activation of Signal Transducer and Activator of Transcription 6.

Aims: Human embryonic stem cell derived-cardiovascular progenitor cells (hESC-CVPCs) are a promising cell source for cardiac repair, while the underlying mechanisms need to be elucidated. We recently observed cardioprotective effects of human pluripotent stem cell (hPSC)-CVPCs in infarcted nonhuman primates, but their effects on inflammation during early phase of myocardial infarction (MI) and the contribution of such effect to the cardioprotection are unclear. Results: Injection of hESC-CVPCs into acutely infarcted myocardium significantly ameliorated the functional worsening and scar formation, concomitantly with reduced inflammatory reactions and cardiomyocyte apoptosis as well as increased vascularization. Moreover, hESC-CVPCs modulated cardiac macrophages toward a reparative phenotype in the infarcted hearts, and such modulation was further confirmed in vitro using human cardiovascular progenitor cell (hCVPC)-conditioned medium (hCVPC-CdM) and highly contained interleukin (IL)-4/IL-13. Furthermore, signal transducer and activator of transcription 6 (STAT6) was activated in hCVPC-CdM- and IL-4/IL-13-treated macrophages in vitro and in hESC-CVPC-implanted MI hearts, resulting in the polarization of macrophages toward a reparative phenotype in the post-MI hearts. However, hESC-CVPC-mediated modulation on macrophages and cardioprotection were abolished in STAT6-deficient MI mice. Innovation: This is the first report about the immunoregulatory role played by hESC-CVPCs in the macrophage polarization in the infarcted hearts, its importance for the infarct repair, and the underlying signaling pathway. The findings provide new insight into the mechanism of microenvironmental regulation of stem cell-based therapy during acute MI. Conclusions: Implantion of hESC-CVPCs during the early phase of MI promotes infarct repair via the modulation of macrophage polarization through secreted cytokine-mediated STAT6 activation. The findings suggest a therapeutic potential by modulating macrophage polarization during acute phase of MI.

Molybdenum disulfide nanoflowers mediated anti-inflammation macrophage modulation for spinal cord injury treatment

Spinal cord injury (SCI) can cause locomotor dysfunctions and sensory deficits. Evidence shows that functional nanodrugs can regulate macrophage polarization and promote anti-inflammatory cytokine expression, which is feasible in SCI immunotherapeutic treatments. Molybdenum disulfide (MoS2) nanomaterials have garnered great attention as potential carriers for therapeutic payload. Herein, we synthesize MoS2@PEG (MoS2 = molybdenum disulfide, PEG = poly (ethylene glycol)) nanoflowers as an effective carrier for loading etanercept (ET) to treat SCI. We characterize drug loading and release properties of MoS2@PEG in vitro and demonstrate that ET-loading MoS2@PEG obviously inhibits the expression of M1-related pro-inflammatory markers (TNF-α, CD86 and iNOS), while promoting M2-related anti-inflammatory markers (Agr1, CD206 and IL-10) levels. In vivo, the mouse model of SCI shows that long-circulating ET-MoS2@PEG nanodrugs can effectively extravasate into the injured spinal cord up to 96 h after SCI, and promote macrophages towards M2 type polarization. As a result, the ET-loading MoS2@PEG administration in mice can protect survival motor neurons, thus, reducing injured areas at central lesion sites, and significantly improving locomotor recovery. This study demonstrates the anti-inflammatory and neuroprotective activities of ET-MoS2@PEG and promising utility of MoS2 nanomaterial-mediated drug delivery.

SAT-340 27-Hydroxycholesterol Acts on Myeloid Cells to Inhibit T Cell Expansion

Breast cancer is the most commonly diagnosed cancer and among the leading causes of death among women in the United States. Our previous work has found that a metabolite of cholesterol, 27-hydroxycholesterol (27HC) promotes breast cancer metastasis in preclinical models. 27HC is a ligand of both the estrogen receptor (ER) and liver X receptor (LXR). Intriguingly, the pro-metastatic effects of 27HC require the presence of myeloid-immune cells. This cell type has been implicated in suppressing acquired immunity, allowing cancer cells to escape immune surveillance. Therefore, we hypothesized that 27HC suppresses the immune system to promote metastasis. To elucidate the immunomodulatory capacity of 27HC, we co-cultured vehicle- or 27HC-treated bone marrow-derived macrophages (BMDMs) with T cells. In support of our hypothesis, we found that 27HC-treated BMDMs inhibited T cell expansion in a dose-dependent manner. Additionally, co-cultured BMDMs treated with 27HC resulted in decreased granzyme B in CD8+ cytotoxic T cells, potentially reducing their capacity to kill cancer cells. The immunosuppressive effect of 27HC-treated BMDMs persisted even without a direct contact between BMDMs and T cells, suggesting that the T cell inhibition is unlikely due to 27HC’s modulation of macrophages’ cell surface markers, in particular MHCII and CD80/86, which are commonly used for BMDM-T cell communication. In order to determine the mechanisms by which 27HC-treated BMDMs suppress T cell proliferation, we first evaluated the relative contributions of two receptors known to bind 27HC: the ERs and LXRs. To this end, BMDMs were exposed to pharmacologic antagonists of, or siRNA against the ERs or LXRs. These BMDMs were subsequently co-cultured with activated T cells to study their impact on T cell proliferation. Interestingly, 27HC’s immunosuppressive capacity required LXR in BMDMs, but not ER, as both siRNA knockdown and pharmacological inhibition of LXR significantly rescued the BMDM-inhibited T cell expansion. A subsequent cytokine array indicated that 27HC treatment could induce the secretion of anti-inflammatory cytokines, potential mediators of the observed decrease in T cell expansion. Therefore, our results suggest that 27HC affects the microenvironment of breast cancer by altering the activity of antigen-presenting cells through the modulation of LXR. This in turn reduces the expansion of T cell function, ultimately resulting in immune escape and tumor progression. Our ongoing work is aimed at elucidating the 27HC-induced LXR signaling pathway in BMDMs and further identifying the downstream targets of 27HC involved in mediating this immunosuppressive phenotype. Our work is of considerable importance given the prevalence of hypercholesterolemia as well as metastatic breast cancer. This work was supported by the grants from the NCI and DOD-BCRP to ERN (R00CA172357, BC171214).

VEGF Therapy Shifts Macrophage Phenotype and Improves Renal Recovery in Chronic Kidney Disease

Chronic kidney disease (CKD) is universally associated with renal microvascular (MV) rarefaction and inflammation. We previously developed a fusion of rh‐vascular endothelial growth factor (VEGF) conjugated to an elastin like polypeptide (ELP) vector. We showed that ELP‐VEGF therapy is renoprotective in a model of unilateral renovascular disease (RVD). Here we test the hypothesis that ELP‐VEGF therapy in a novel model of CKD will recover renal function and MV rarefaction driven partly by modulation of renal macrophages to a pro‐angiogenic phenotype.CKD was induced in 10 pigs by bilateral RVD combined with diet‐induced hypercholesterolemia. After 6 weeks, pigs received a single intrarenal dose of ELP‐VEGF or placebo and were observed for 8 weeks. Renal blood flow (RBF) and glomerular filtration rate (GFR) were quantified using multidetector computed tomography before, and 4 and 8 weeks after ELP‐VEGF therapy. Blood and urine were collected to quantify serum creatinine and albuminuria. Pigs were then euthanized and renal MV density, VEGF expression, and inflammation were quantified. Renal macrophage infiltration and phenotype was determined by concurrent staining for CD68, indoleamine 2,3 dioxygenase (IDO), and mannose receptor c type 1 (MRC1) (indicating total, M1, and M2 macrophages respectively). Further staining was performed to colocalize MRC1 and VEGF. An additional 5 pigs served as normal controls.RBF and GFR were reduced in all pigs at 6 weeks. ELP‐VEGF therapy induced a progressive recovery of RBF and GFR, accompanied by improved MV density, VEGF expression, and reduced albuminuria (1.8 ± 0.3 mg/dL vs. 2.9 ± 0.9 mg/dL in untreated CKD, p < 0.05) and creatinine (160 ± 10 μmol/L vs. 202 ± 16 μmol/L in untreated CKD, p < 0.05). Heavy IDO+/MRC1− pro‐inflammatory M1 macrophage infiltration was observed in untreated CKD and was shifted to a IDO−/MRC1+ anti‐inflammatory M2 phenotype after ELP‐VEGF therapy. Furthermore, augmented co‐expression of VEGF was observed in the MRC1+ renal macrophages (Figure).The progressive recovery of renal function far outlasted the life of administered ELP‐VEGF, suggesting that this single dose activates an endogenous mechanism of renal repair to sustain long term improvement. Accumulation of VEGF expressing M2 macrophages in the renal parenchyma may account for the recovery of MV rarefaction and renal hemodynamics after ELP‐VEGF treatment in CKD. These results suggest that modulation of macrophages towards a highly angiogenic M2 phenotype may constitute a prominent mechanism of renal recovery after ELP‐VEGF therapy in CKD.Support or Funding InformationSupport: HL95638, HL51971, GM104357, HL121527 (NIH), and EIA18490005 and IPA34170267 (AHA).This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Preconditioned or IL4-Secreting Mesenchymal Stem Cells Enhanced Osteogenesis at Different Stages

Pathogen-associated molecular patterns, damage-associated molecular patterns, and other noxious stimuli activate macrophages to induce the proinflammatory responses. Modulation of inflammatory macrophages (M1) into an anti-inflammatory tissue repair macrophage (M2) phenotype at the appropriate time optimizes bone remodeling and regeneration. Simulating the proinflammatory stimuli by using preconditioned mesenchymal stem cells (MSCs) at an earlier stage, and alleviate the inflammation by using IL4-secreting MSCs at a later stage could further optimize bone regeneration in chronic inflammatory conditions, including periprosthetic osteolysis.

Tumor-specific macrophage targeting through recognition of retinoid X receptor beta

Macrophages play important and diverse roles during cancer progression. However, cancer therapies based on macrophage modulation are lacking in tools that can recognize and deliver therapeutic payloads to macrophages in a tumor-specific manner. As a result, treatments tend to interfere with normal macrophage functions in healthy organs. We previously identified a macrophage-binding peptide, termed CRV. Here, we show that upon systemic administration into tumor-bearing mice, CRV selectively homes to tumors, extravasates, and preferentially binds to macrophages within. CRV exhibits a higher affinity for tumor macrophages than for other cells in tumors or for other macrophage types elsewhere in the body. We further identified and validated retinoid X receptor beta (RXRB) as the CRV receptor. Intriguingly, although it is known as a nuclear receptor, RXRB shows a prominent cell surface localization that is largely restricted to tumor macrophages. Systemic administration of anti-RXRB antibodies also results in tumor-selective binding to macrophages similar to CRV. Lastly, we demonstrate the ability of CRV to improve the delivery of nano-carriers into solid tumors and macrophages within. In summary, we describe here a novel cell surface marker and targeting tools for tumor macrophages that may aid in future development of macrophage-modulatory cancer therapies.

Evaluation of epigallocatechin-3-gallate (EGCG)-modified scaffold determines macrophage recruitment

Biomaterials based on the modulation of macrophages have gained increased attention recently. Macrophages are generally divided into the pro-inflammatory M1 and pro-regenerative M2 phenotypes. Macrophages play a pivotal role in bone regeneration by regulating osteoblast differentiation and secreting pro-regenerative factors. In the present study, epigallocatechin-3-gallate (EGCG)-modified collagen membranes downregulated the expression of inflammatory factors and promoted the recruitment of M2 macrophages, as evidenced by the expression of M2 macrophage markers (CD163 and CD206). It is further demonstrated that the recruitment of M2 macrophages may be involved with CC chemokine receptor type 2 (CCR2) signaling, with a significant downregulation of CD206 following CCR2 knockout. These results suggested that EGCG-modified collagen membranes may modulate the recruitment of macrophages and can be applied to guided bone regeneration and guided tissue regeneration.

Building capacity for macrophage modulation and stem cell recruitment in high-stiffness hydrogels for complex periodontal regeneration: Experimental studies in vitro and in rats

Recently, we found that although high-stiffness matrices stimulated osteogenic differentiation of bone marrow-derived stromal cells (BMSCs), the macrophages (Mφs) in high-stiffness transglutaminase crosslinked gelatins (TG-gels) tended to undergo M1 polarization and hence compromised cell osteogenesis. In this study, we hypothesized that the copresentation of interleukin (IL)-4 and stromal cell-derived factor (SDF)-1α in high-stiffness TG-gels may enhance periodontal regeneration by modulating Mφ polarization and promoting endogenous stem cell recruitment. We found that Mφs were more likely to polarize toward an immunomodulatory M2 state in the presence of IL-4 and hence positively influence the osteogenic differentiation of BMSCs when these cells coexisted in either indirect or direct co-culture systems. In cell migration assays, BMSCs exhibited an enhanced capability to move toward gels containing SDF-1α, and more cells could be recruited into the three-dimensional matrix of TG-gels. When TG-gels containing IL-4 and/or SDF-1α were used to repair periodontal defects, more new bone (MicroCT) was formed in animals that received the dual cytokine-loaded transplants at 4 weeks postsurgery. Mφs were recruited to all the transplanted gels, and after one week, more M1-phenotype cells were found in the groups without IL-4, while the presence of IL-4 was more likely to result in M2 polarization (immunofluorescence staining). When the tissue biopsies were histologically examined, the TG-gels containing both IL-4 and SDF-1α led to a generally satisfactory regeneration with respect to attachment recovery (epithelial and connective tissue) and hybrid tissue regeneration (bone, periodontal ligament and cementum). Our data suggest that the incorporation of IL-4 into high-stiffness TG-gels may promote the M2 polarization of Mφs and that SDF-1α can be applied to guide endogenous cell homing. Overall, building capacity for Mφ modulation and cell recruitment in high-stiffness hydrogels represents a simple and effective strategy that can support high levels of periodontal tissue regeneration. Statement of significanceThe development of hydrogel-based regenerative therapies centered on the mobilization and stimulation of native cells for therapeutics opens a window toward realizing periodontal endogenous regeneration. In the present study, the parallel use of immunomodulatory and homing factors in high-stiffness hydrogel materials is shown to induce stem cell homing, modulate cell differentiation and indeed induce regrowth of the periodontium. We found that incorporation of interleukin (IL)-4 in high-stiffness TG-gels coaxed macrophages to polarize into M2 phenotypes, and stromal cell-derived factor (SDF)-1α could be applied to direct endogenous cell homing. Hence, we present for the first time a clinically relevant strategy based on macrophage modulation and host cell recruitment that can support high levels of periodontal tissue regeneration.

Curcumin as a potential modulator of M1 and M2 macrophages: new insights in atherosclerosis therapy.

Accumulation of macrophages within the artery wall is an eminent feature of atherosclerotic plaques. Macrophages are influenced by various plaque microenvironmental stimuli, such as oxidized lipids, cytokines, and senescent erythrocytes, and thereby polarize into two main phenotypes called proinflammatory M1 and anti-inflammatory M2 macrophages. In the hemorrhagic zones of atheroma, upon exposure to iron, sequestration of iron by M1 macrophages results in an uncontrolled proinflammatory phenotype impairing wound healing, while M2 macrophages phagocytose both apoptotic cells and senescent erythrocytes. M1 macrophages are prominent phenotype in the unstable plaques, in which plaque shoulder contains macrophages mainly present markers of M1 phenotype, whereas the fibrous cap encompassing the necrotic lipid core content macrophages expressed markers of both M1 and M2 subtypes. The abovementioned findings suggest macrophage modulation as a potent approach for atherosclerosis therapy. Curcumin is a polyphenol dietary derived from turmeric with numerous pharmacological activities. Recent in vitro and in vivo studies have indicated that curcumin exerted lipid-lowering effects, and also can modulate function of different macrophage subsets in various macrophage-involved diseases. The current review aimed to present role of macrophage subtypes in atherosclerosis development and progression, and to understand effect of curcumin on macrophage polarization and foam cell formation in the atherosclerosis lesions. Overall, we would address important targets for macrophage modulation in atherosclerotic plaques.

Infection and Functional Modulation of Human Monocytes and Macrophages by Varicella-Zoster Virus.

Varicella-zoster virus (VZV) is associated with viremia during primary infection that is presumed to stem from infection of circulating immune cells. While VZV has been shown to be capable of infecting a number of different subsets of circulating immune cells, such as T cells, dendritic cells, and NK cells, less is known about the interaction between VZV and monocytes. Here, we demonstrate that blood-derived human monocytes are permissive to VZV replication in vitro VZV-infected monocytes exhibited each temporal class of VZV gene expression, as evidenced by immunofluorescent staining. VZV virions were observed on the cell surface and viral nucleocapsids were observed in the nucleus of VZV-infected monocytes by scanning electron microscopy. In addition, VZV-infected monocytes were able to transfer infectious virus to human fibroblasts. Infected monocytes displayed impaired dextran-mediated endocytosis, and cell surface immunophenotyping revealed the downregulation of CD14, HLA-DR, CD11b, and the macrophage colony-stimulating factor (M-CSF) receptor. Analysis of the impact of VZV infection on M-CSF-stimulated monocyte-to-macrophage differentiation demonstrated the loss of cell viability, indicating that VZV-infected monocytes were unable to differentiate into viable macrophages. In contrast, macrophages differentiated from monocytes prior to exposure to VZV were highly permissive to infection. This study defines the permissiveness of these myeloid cell types to productive VZV infection and identifies the functional impairment of VZV-infected monocytes.IMPORTANCE Primary VZV infection results in the widespread dissemination of the virus throughout the host. Viral transportation is known to be directly influenced by susceptible immune cells in the circulation. Moreover, infection of immune cells by VZV results in attenuation of the antiviral mechanisms used to control infection and limit spread. Here, we provide evidence that human monocytes, which are highly abundant in the circulation, are permissive to productive VZV infection. Furthermore, monocyte-derived macrophages were also highly permissive to VZV infection, although VZV-infected monocytes were unable to differentiate into macrophages. Exploring the relationships between VZV and permissive immune cells, such as human monocytes and macrophages, elucidates novel immune evasion strategies and provides further insight into the control that VZV has over the immune system.

Neuropeptide FF modulates neuroendocrine and energy homeostasis through hypothalamic signaling.

Neuropeptide FF (NPFF) is known as a morphine-modulating peptide and was first isolated in 1985. It has been characterized as an RF-amide peptide. The traditional role of NPFF is mediation of the pain response, and it displays both anti-opioid and pro-opioid actions through central nervous system. In the recent decade, additional evidence has revealed some untraditional features of NPFF, such as regulation of the neuroendocrine system, energy homeostasis, anti-inflammation, pain transmission, and peripheral modulation of adipose tissue macrophages. Neuropeptide FF receptor 2 (NPFFR2) is a physiological receptor of NPFF, and the actions of NPFF may occur through downstream NPFFR2 signaling. NPFF and NPFFR2 increase the neuronal activity in various areas of the hypothalamus to modulate the hypothalamic-pituitary-adrenal axis, the autonomic nervous system, food intake, and energy balance. These underlying cellular mechanisms have been explored in the past few years. Here, we review the impact of NPFF and related RF-amide peptides on hypothalamic function. The interaction of NPFF with NPFFR2 in the hypothalamus is emphasized, and NPFF-NPFFR2 system may represent an important therapeutic target in hypothalamic-related disorders in the future.

SAG/RBX2 E3 Ubiquitin Ligase Differentially Regulates Inflammatory Responses of Myeloid Cell Subsets.

Macrophages form an important component of the innate immune system and serve as first responders against invading pathogens. While pathways critical for initiation of inflammatory responses between macrophages and other LysM+ myeloid cells are largely similar, it remains unknown whether a specific pathway has differential effects on inflammatory responses mediated between these cells. Recent studies demonstrated that depletion of SAG (Sensitive to Apoptosis Gene), an E3 ubiquitin ligase, blocked inflammatory responses generated by macrophages and dendritic cells in response to LPS in cell culture settings. However, the in vivo role of Sag on modulation of macrophages and neutrophil is not known. Here we generated LysM-Cre/Sagfl/fl mice with selective Sag deletion in myeloid lineage, and found that in contrast to in vitro observations, LysM-Cre/Sagfl/fl mice showed increased serum levels of proinflammatory cytokines and enhanced mortality in response to LPS. Interestingly, while Sag−/− macrophages released less proinflammatory cytokines, Sag−/− neutrophils released more. Mechanistically, expression of a list of genes response to LPS was significantly altered in bone marrow cells from LysM-Cre+/Sagfl/fl mice after LPS challenge. Specifically, induction by LPS of myeloperoxidase (Mpo), a key neutrophil enzyme, and Elane, neutrophil expressed elastase, was significantly decreased upon Sag depletion. Collectively, our study revealed that Sag plays a differential role in the activation of macrophages and neutrophils.

Lipopolysaccharide-Preconditioned Periodontal Ligament Stem Cells Induce M1 Polarization of Macrophages through Extracellular Vesicles.

Periodontitis is a common disease characterized by chronic inflammation and tissue destruction of gums. Human periodontal ligament stem cells (PDLSCs), derived from the periodontium, have stem cell properties similar to those of mesenchymal stem cells. PDLSCs possess not only the potential to differentiate into other tissues, but also immunomodulatory abilities. Macrophages play a critical role in periodontal disease, but little is known regarding the role of PDLSCs in macrophage modulation during inflammation. In this study, we investigated the effect of PDLSCs on the macrophage cell line. While the conditioned media from PDLSCs under normal culture conditions did not affect macrophage polarization, the lipopolysaccharide (LPS)-preconditioned PDLSCs induced significant changes in M1 polarization. Extracellular vesicles (EVs) isolated from the conditioned media of LPS-preconditioned PDLSCs induced strong M1 polarization of macrophages. Additionally, the M1 polarization was abolished by DNase I treatment of EVs. Therefore, the LPS-stimulated PDLSCs induce M1 polarization of macrophages through EVs, suggesting that the EVs from PDLSCs might be a potential therapeutic target for inflammation in the periodontium.

Mycobacterium tuberculosis host cell interaction: Role of latency associated protein Acr-1 in differential modulation of macrophages.

Mycobacterium tuberculosis (M.tb) contrives intracellular abode as a strategy to combat antibody onslaught. Additionally, to thrive against hostile ambiance inside host macrophages, the pathogen inhibits phago-lysosomal fusion. Finally, to further defy host cell offensives, M.tb opts for dormant phase, where it turns off or slows down most of its metabolic process as an added stratagem. While M.tb restrains most of its metabolic activities during dormancy, surprisingly latency-associated alpha-crystallin protein (Acr-1) is expressed most prominently during this phase. Interestingly, several previous studies described the potential of Acr-1 to induce the robust immuno-prophylactic response in the immunized host. It is intriguing to comprehend the apparent discrepancy that the microbe M.tb overexpresses a protein that has the potential to prime host immune system against the pathogen itself. Keeping this apparent ambiguity into consideration, it is imperative to unravel intricacies involved in the exploitation of Acr-1 by M.tb during its interaction with host immune cells. The present study suggests that Acr-1 exhibits diverse role in the maturation of macrophages (MΦs) and related immunological responses. The early encounter of bone marrow derived immune cells (pre-exposure during differentiation to MΦs) with Acr-1 (AcrMΦpre), results in hampering of their function. The pre-exposure of naïve MΦs with Acr-1 induces the expression of TIM-3 and IL-10. In contrast, exposure of fully differentiated MΦs to Acr-1 results in their down-modulation and induces the phosphorylation of STAT-1 and STAT-4 in host MΦs. Furthermore, Acr-1 mediated activation of MΦs results in the induction of Th1 and Th17 phenotype by activated T lymphocyte.

Influence of macrophage modulation on the state of extra islet insulin-producing system in hypergycemia

Influence of macrophage modulation on the state of extra islet insulin-producing system in hypergycemia

The lack of PI3Kγ favors M1 macrophage polarization and does not prevent kidney diseases progression

Acute kidney injury (AKI) and chronic kidney disease (CKD) are major concerns in worldwide public health, and their pathophysiology involves immune cells activation, being macrophages one of the main players of both processes. It is suggested that metabolic pathways could contribute to macrophage modulation and phosphatidylinositol‑3 kinase (PI3K) pathway was shown to be activated in kidneys subjected to ischemia and reperfusion as well as unilateral ureteral obstruction (UUO). Although PI3K inhibition is mostly associated with anti-inflammatory response, its use in kidney injuries has been shown controversial results, which indicates the need for further studies. Our aim was to unveil the role of PI3Kγ in macrophage polarization and in kidney diseases development. We analyzed bone-marrow macrophages polarization from wild-type (WT) and PI3Kγ knockout (PI3K KO) animals. We observed increased expression of M1 (CD86, CCR7, iNOS, TNF, CXCL9, CXCL10, IL-12 and IL-23) and decreased of M2 (CD206, Arg-1, FIZZ1 and YM1) markers in the lack of PI3Kγ. And this modulation was accompanied by higher levels of inflammatory cytokines in PI3K KO M1 cells. PI3K KO mice had increased M1 in steady state kidneys, and no protection was observed in these mice after acute and chronic kidney insults. On the contrary, they presented higher levels of protein-to-creatinine ratio and Kim-1 expression and increased tubular injury. In conclusion, our findings demonstrated that the lack of PI3Kγ favors M1 macrophages polarization providing an inflammatory-prone environment, which does not prevent kidney diseases progression.

Abstract A097: Regulation of immunophenotype modulation of monocytes-macrophages from M1 to M2 by prostate cancer cell culture supernatant via the transcription factor STAT3

Abstract Background: The transcription factor STAT3 has a prominent innate immunity effect on cancer progression. We determined the regulation of STAT3 in the immunophenotype modulation of macrophages from M1 to M2 induced by the cell culture supernatant of the prostate cancer line PC3. Methods: Monocyte-macrophages from healthy donors were cultured in the supernatant of PC3 cells, membrane proteins and intracytoplasmic and phosphorylated STAT3 were measured using flow cytometry, and cytokines and growth factors were studied using luminescence. Cytotoxicity and nitric oxide were evaluated via colorimetric assays. Results: The supernatant of prostate tumor PC3 cells effectively induced macrophages toward an M2 profile, and the expression of phosphorylated STAT3 in the monocytes-macrophages notably increased. In the group of monocytes-macrophages treated with an STAT3 inhibitor, the macrophages were induced towards an M1 phenotype. Conclusions: In this study, we show that the secretion profile of PC3 prostate cancer cells induces a change in macrophage phenotype from M1 to M2, and this phenomenon is related to phosphorylation of the transcription factor STAT3. Citation Format: Raul Solis, Alejandro Bravo, Jr., Georgina Hernandez, Alejandro Bravo. Regulation of immunophenotype modulation of monocytes-macrophages from M1 to M2 by prostate cancer cell culture supernatant via the transcription factor STAT3 [abstract]. In: Proceedings of the AACR Special Conference: Prostate Cancer: Advances in Basic, Translational, and Clinical Research; 2017 Dec 2-5; Orlando, Florida. Philadelphia (PA): AACR; Cancer Res 2018;78(16 Suppl):Abstract nr A097.

NAMPT: A pleiotropic modulator of monocytes and macrophages

Nicotinamide phosphoribosyltransferase (NAMPT) is the bottleneck enzyme of the NAD salvage pathway and thereby is a controller of intracellular NAD concentrations. It has been long known that the same enzyme can be secreted by a number of cell types and acts as a cytokine, although its receptor is at present unknown. Investigational compounds have been developed that target the enzymatic activity as well as the extracellular action (i.e. neutralizing antibodies). The present contribution reviews the evidence that links intracellular and extracellular NAMPT to myeloid biology, for example governing monocyte/macrophage differentiation, polarization and migration. Furthermore, it reviews the evidence that links this protein to some disorders in which myeloid cells have a prominent role (acute infarct, inflammatory bowel disease, acute lung injury and rheumatoid arthritis) and the data showing that inhibition of the enzymatic activity or the neutralization of the cytokine is beneficial in preclinical animal models.