Shift In Macrophage Polarization Research Articles

Myeloid CD40 deficiency reduces atherosclerosis by impairing macrophages' transition into a pro-inflammatory state.

CD40 and its ligand, CD40L, play a critical role in driving atherosclerotic plaque development. Disrupted CD40-signalling reduces experimental atherosclerosis and induces a favourable stable plaque phenotype. We recently showed that small molecule-based inhibition of CD40-tumour necrosis factor receptor associated factor-6 interactions attenuates atherosclerosis in hyperlipidaemic mice via macrophage-driven mechanisms. The present study aims to detail the function of myeloid CD40 in atherosclerosis using myeloid-specific CD40-deficient mice. Cd40flox/flox and LysM-cre Cd40flox/flox mice on an Apoe-/- background were generated (CD40wt and CD40mac-/-, respectively). Atherosclerotic lesion size, as well as plaque macrophage content, was reduced in CD40mac-/- compared to CD40wt mice, and their plaques displayed a reduction in necrotic core size. Transcriptomics analysis of the CD40mac-/- atherosclerotic aorta revealed downregulated pathways of immune pathways and inflammatory responses. Loss of CD40 in macrophages changed the representation of aortic macrophage subsets. Mass cytometry analysis revealed a higher content of a subset of alternative or resident-like CD206+CD209b- macrophages in the atherosclerotic aorta of CD40mac-/- compared to CD40wt mice. RNA-sequencing of bone marrow-derived macrophages of CD40mac-/- mice demonstrated upregulation of genes associated with alternatively activated macrophages (including Folr2, Thbs1, Sdc1, and Tns1). We here show that absence of CD40 signalling in myeloid cells reduces atherosclerosis and limits systemic inflammation by preventing a shift in macrophage polarization towards pro-inflammatory states. Our study confirms the merit of macrophage-targeted inhibition of CD40 as a valuable therapeutic strategy to combat atherosclerosis.

MicroRNA-146a-5p-modified human umbilical cord mesenchymal stem cells enhance protection against diabetic nephropathy in rats through facilitating M2 macrophage polarization

BackgroundDiabetic nephropathy (DN) is a severe complication of diabetes mellitus and a common cause of end-stage renal disease (ESRD). Mesenchymal stem cells (MSCs) possess potent anti-inflammatory and immunomodulatory properties, which render them an attractive therapeutic tool for tissue damage and inflammation.MethodsThis study was designed to determine the protective effects and underlying mechanisms of human umbilical cord-derived MSCs (UC-MSCs) on streptozotocin-induced DN. Renal function and histological staining were used to evaluate kidney damage. RNA high-throughput sequencing on rat kidney and UCMSC-derived exosomes was used to identify the critical miRNAs. Co-cultivation of macrophage cell lines and UC-MSCs-derived conditional medium were used to assess the involvement of macrophage polarization signaling.ResultsUC-MSC administration significantly improved renal function, reduced the local and systemic inflammatory cytokine levels, and attenuated inflammatory cell infiltration into the kidney tissue in DN rats. Moreover, UC-MSCs shifted macrophage polarization from a pro-inflammatory M1 to an anti-inflammatory M2 phenotype. Mechanistically, miR-146a-5p was significantly downregulated and negatively correlated with renal injury in DN rats as determined through high-throughput RNA sequencing. Importantly, UC-MSCs-derived miR-146a-5p promoted M2 macrophage polarization by inhibiting tumor necrosis factor receptor-associated factor-6 (TRAF6)/signal transducer and activator of transcription (STAT1) signaling pathway. Furthermore, miR-146a-5p modification in UC-MSCs enhanced the efficacy of anti-inflammation and renal function improvement.ConclusionsCollectively, our findings demonstrate that UC-MSCs-derived miR-146a-5p have the potential to restore renal function in DN rats through facilitating M2 macrophage polarization by targeting TRAF6. This would pave the way for the use of miRNA-modified cell therapy for kidney diseases.

IDF21-0354 Glucoraphanin has the therapeutic potential of resolving hepatic steatosis in a murine model of diet-induced obesity

Background: Glucoraphanin (GR) is a natural glucosinolate abundantly found in broccoli sprouts. GR is converted to sulforaphane by myrosinase enzyme and the metabolite is a potent activator of a nuclear factor (erythroid-derived 2)-like 2 (Nrf2). Activation of Nrf2 induces antioxidant and detoxication-related genes, thus leading to cellular protection against oxidative stress. We have demonstrated that GR has preventive effects on impairment of glucose homeostasis in diet-induced obese (DIO) mice via an increment in energy expenditure, shifting macrophage polarization in liver and adipose tissue, and changing microbiota characteristics.

PKCα/ZFP64/CSF1 axis resets the tumor microenvironment and fuels anti-PD1 resistance in hepatocellular carcinoma

Despite remarkable advances in treatment, most patients with hepatocellular carcinoma (HCC) respond poorly to anti-programmed cell death 1 (anti-PD1) therapy. A deeper insight into the tolerance mechanism of HCC against this therapy is urgently needed. We performed next-generation sequencing, multiplex immunofluorescence, and dual-color immunohistochemistry and constructed an orthotopic HCC xenograft tumor model to identify the key gene associated with anti-PD1 tolerance. A spontaneously tumorigenic transgenic mouse model, an invitro coculture system, mass cytometry, and multiplex immunofluorescence were used to explore the biological function of zinc finger protein 64 (ZFP64) on tumor progression and immune escape. Molecular and biochemical strategies like RNA-sequencing, chromatin immunoprecipitation-sequencing and mass spectrometry were used to gain insight into the underlying mechanisms of ZFP64. We showed that ZFP64 is frequently upregulated in tumor tissues from patients with anti-PD1-resistant HCC. Elevated ZFP64 drives anti-PD1 resistance by shifting macrophage polarization toward an alternative activation phenotype (M2) and fostering an inhibitory tumor microenvironment. Mechanistically, we primarily demonstrated that protein kinase C alpha (PKCα) directly phosphorylates ZFP64 at S226, leading to its nuclear translocation and the transcriptional activation of macrophage colony-stimulating factor (CSF1). HCC-derived CSF1 transforms macrophages to the M2 phenotype to drive immune escape and anti-PD1 tolerance. Notably, Gö6976, a protein kinase inhibitor, and lenvatinib, a multi-kinase inhibitor, reset the tumor microenvironment and restore sensitivity to anti-PD1 by blocking the PKCα/ZFP64/CSF1 axis. We propose that the PKCα/ZFP64/CSF1 axis is critical for triggering immune evasion and anti-PD1 tolerance. Inhibiting this axis with Gö6976 or lenvatinib overcomes anti-PD1 resistance in HCC. Despite remarkable treatment progress, most patients with hepatocellular carcinoma respond poorly to anti-PD1 therapy (a type of immunotherapy). A deeper insight into the tolerance mechanisms to this therapy is urgently needed. Herein, we unravel a previously unexplored mechanism linking tumor progression, macrophage polarization, and anti-PD1 resistance, and offer an attractive novel target for anti-PD1 combination therapy, which may benefit patients with hepatocellular carcinoma.

Asymptomatic Hyperuricemia Promotes Recovery from Ischemic Organ Injury by Modulating the Phenotype of Macrophages.

Acute organ injury, such as acute kidney injury (AKI) and disease (AKD), are major causes of morbidity and mortality worldwide. Hyperuricemia (HU) is common in patients with impaired kidney function but the impact of asymptomatic HU on the different phases of AKI/AKD is incompletely understood. We hypothesized that asymptomatic HU would attenuate AKD because soluble, in contrast to crystalline, uric acid (sUA) can attenuate sterile inflammation. In vitro, 10 mg/dL sUA decreased reactive oxygen species and interleukin-6 production in macrophages, while enhancing fatty acid oxidation as compared with a physiological concentration of 5 mg/dL sUA or medium. In transgenic mice, asymptomatic HU of 7–10 mg/dL did not affect post-ischemic AKI/AKD but accelerated the recovery of kidney excretory function on day 14. Improved functional outcome was associated with better tubular integrity, less peritubular inflammation, and interstitial fibrosis. Mechanistic studies suggested that HU shifted macrophage polarization towards an anti-inflammatory M2-like phenotype characterized by expression of anti-oxidative and metabolic genes as compared with post-ischemic AKI-chronic kidney disease transition in mice without HU. Our data imply that asymptomatic HU acts as anti-oxidant on macrophages and tubular epithelial cells, which endorses the recovery of kidney function and structure upon AKI.

A Novel Anti-Inflammatory Renoprotective Effect of GLP-1 Receptor Agonists in Type 1 Diabetes: Shifting Macrophage Polarization

A Novel Anti-Inflammatory Renoprotective Effect of GLP-1 Receptor Agonists in Type 1 Diabetes: Shifting Macrophage Polarization

Posttranscriptional control of PLOD1 in adipose-derived stem cells regulates scar formation through altering macrophage polarization.

BackgroundThe level of cutaneous scar formation is a critical parameter to determine the success of skin wound healing. Adipose-derived mesenchymal stem cells (AMSCs) have been applied to improve treatment of cutaneous injury with the purpose of reducing scar formation.MethodsThe levels of procollagen-lysine 1,2-oxoglutarate 5-dioxygenase 1 (PLOD1) were assessed at scar sites. Then, PLOD1 in AMSCs was depleted by either expression of a PLOD1-specific short-hair interfering RNA (shPLOD1) or by expression of microRNA-449 (miR-449) that targets and suppresses protein translation of PLOD1 through 3 prime untranslated region (3'-UTR) interfering. For induction of skin injury, a blade cut of 1.5-cm long and 2-mm thick was made on the middle back of the mice. Transplantation of either AMSCs-shPLOD1 or AMSCs-miR-449 into the injured region of the mice was performed via tail vein injection. The fibrosis as well as underlying mechanisms were assessed.ResultsThe AMSCs expressed high levels of PLOD1, a potent stimulator of fibrosis. We knocked down PLOD1 in AMSCs by expression of either shPLOD1 or miR-449. Transplantation of either AMSCs-shPLOD1 or AMSCs-miR-449 significantly reduced the fibrotic process in the injured region of the mice to a similar degree. Mechanistically, transplantation of either AMSCs-shPLOD1 or AMSCs-miR-449 shifted macrophage polarization from M2 to M1-like and reduced both reactive oxygen species (ROS) and activation of myofibroblasts from fibroblasts.ConclusionsSuppression of PLOD1 levels in AMSCs either directly by shPLOD1 or indirectly by miR-449 may substantially improve the anti-fibrotic potential of AMSCs during wound healing, likely through altering macrophage polarization.

Abstract CT144: Development of GMI-1359, a novel agent targeting tumor-microenvironment cross-talk in bone metastatic cancer

Abstract Pre-clinical and clinical data suggest that the bone marrow (BM) environment provides breast cancer (BC) cells a protective haven against chemotherapeutic insult, endocrine therapies, and immune recognition. Novel agents that intercept cross-talk between BC cells and the host could therefore improve the depth of response to therapies and potentially increase overall survival in metastatic BC. We have previously shown that bone metastatic BC cells reside in perivascular niches expressing high levels of SDF-1α (CXCL12) and E-selectin, two molecules for which emerging data have demonstrated a significant role in metastatic BC progression. Our prior pre-clinical studies have shown that E-selectin inhibition specifically prevents circulating BC cells from homing to the BM, whereas CXCR4 blockade mobilizes micrometastases from the marrow into circulation, where they may be sensitized to chemotherapeutic cell kill. Given the normal role of these molecules in host immune responses, E-selectin/CXCR4 blockade has additional potential to impact the tumor immune microenvironment. GMI-1359 is a small molecule, glycomimetic compound with dual inhibitory activity against E-selectin and CXCR4. We hypothesize that GMI-1359 can block E-selectin and CXCR4 binding to E-selectin ligands and SDF-1, disrupting the protective effects of the bone microenvironment on tumor cells. A single-center, phase 1b, open-label, single and multiple ascending dose study (NCT04197999) is therefore evaluating GMI-1359 in patients with HR+ metastatic breast cancer with bony metastases who are stable or minimally progressive on endocrine therapy, with or without a CDK4/6 inhibitor. To date, 2 patients have been enrolled and received single monthly doses of 3.5, 5.0 and 7.0 mg/kg followed by 3 daily doses of 7 mg/kg. Both patients have completed treatment with no dose limiting toxicities observed. Coincident with GMI-1359 administration at all dose levels, we observed mobilization of CD34+ cells coupled with a reduction in elevated serum sE-selectin levels, demonstrating the dual functionality of the compound. Initial peripheral blood immunophenotype data on one patient revealed a redistribution of myeloid derived suppressor cells and a shift in macrophage polarization from M2 to M1. Notably, we observed similar immune alterations in ongoing preclinical studies in the E0771 syngeneic BC mouse model. We found that orthotopically-engrafted mice treated with single agent 1359 had a significant increase in the ratio of CD8/Tregulatory cells isolated from the primary tumor and BM. We also observed a decrease in primary tumor M-MDSCs and lung metastasis-associated macrophages. In summary, our preliminary clinical data suggest that GMI-1359 is well-tolerated and elicits on-target effects expected from disruption of the host microenvironment. Ongoing clinical and preclinical work will define the efficacy of this strategy to enhance responses to chemo and immune therapies. Citation Format: P. Kelly Marcom, Trevor T. Price, Andrew S. Murray, William E. Fogler, John L. Magnani, Helen Thackray, Eric Feldman, Dorothy Sipkins. Development of GMI-1359, a novel agent targeting tumor-microenvironment cross-talk in bone metastatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr CT144.

Pinosylvin Shifts Macrophage Polarization to Support Resolution of Inflammation.

Pinosylvin is a natural stilbenoid found particularly in Scots pine. Stilbenoids are a group of phenolic compounds identified as protective agents against pathogens for many plants. Stilbenoids also possess health-promoting properties in humans; for instance, they are anti-inflammatory through their suppressing action on proinflammatory M1-type macrophage activation. Macrophages respond to environmental changes by polarizing towards proinflammatory M1 phenotype in infection and inflammatory diseases, or towards anti-inflammatory M2 phenotype, mediating resolution of inflammation and repair. In the present study, we investigated the effects of pinosylvin on M2-type macrophage activation, aiming to test the hypothesis that pinosylvin could polarize macrophages from M1 to M2 phenotype to support resolution of inflammation. We used lipopolysaccharide (LPS) to induce M1 phenotype and interleukin-4 (IL-4) to induce M2 phenotype in J774 murine and U937 human macrophages, and we measured expression of M1 and M2-markers. Interestingly, along with inhibiting the expression of M1-type markers, pinosylvin had an enhancing effect on the M2-type activation, shown as an increased expression of arginase-1 (Arg-1) and mannose receptor C type 1 (MRC1) in murine macrophages, and C-C motif chemokine ligands 17 and 26 (CCL17 and CCL26) in human macrophages. In IL-4-treated macrophages, pinosylvin enhanced PPAR-γ expression but had no effect on STAT6 phosphorylation. The results show, for the first time, that pinosylvin shifts macrophage polarization from the pro-inflammatory M1 phenotype towards M2 phenotype, supporting resolution of inflammation and repair.

Zoledronate Causes a Systemic Shift of Macrophage Polarization towards M1 In Vivo.

Background: Immunomodulatory properties of bisphosphonates (BP) are suggested to contribute to the development of medication-associated osteonecrosis of the jaw (MRONJ). Furthermore, bisphosphonate-derived immune modulation might contribute to the anti-metastatic effect observed in breast cancer patients. Macrophages are potential candidates for the mediation of immunomodulatory effects of bisphosphonates. The study aimed to investigate the influence of bisphosphonates alone and in combination with surgical trauma on systemic macrophage polarization (M1 vs. M2) using an in vivo rat model. Methods: A total of 120 animals were divided into four groups. Groups 2 and 4 were treated with 8 × 40 μg/kg body weight of the BP Zoledronate i.p. (week 0–7). Groups 3 and 4 were exposed to surgical trauma (week 8, tooth extraction + tibia fracture), whereas in Group 1 neither medication nor surgical trauma was applied. After 8, 10, 12 and 16 weeks, skin, lung and spleen were immunohistochemically examined for macrophage polarization via expression analysis of CD68, CD163 and iNOS using a tissue microarray (TMA). Results: A significant shift of macrophage polarization towards M1 was observed in skin, spleen and lung tissue of animals, with and without surgical trauma, treated with BP when compared to those without BP application. Surgical trauma did not cause a significant increase towards M1 polarization. Conclusions: BP application leads to a systemic pro-inflammatory situation in vivo, independent of surgical trauma, as evidenced by the shift in macrophage polarization towards M1 in various somatic tissues. This provides a possible explanation for the clinically observed anti-tumor effect of bisphosphonates and might also contribute to pathogenesis of MRONJ.

Dexamethasone Promotes Aspergillus fumigatus Growth in Macrophages by Triggering M2 Repolarization via Targeting PKM2.

Since long-term corticosteroid treatment is associated with emerging opportunistic fungal infections causing high morbidity and mortality in immune-suppressed individuals, here we characterized the impact of dexamethasone (Dex) treatment on Aspergillus fumigatus-related immune modulation. We found by high content screening and flow cytometric analyses that during monocyte-to-macrophage differentiation, as little as 0.1 µg/mL Dex resulted in a shift in macrophage polarization from M1 to M2-like macrophages. This macrophage repolarization mediated via Dex was characterized by significant upregulation of the M2 marker CD163 and downmodulation of M1 markers CD40 and CD86 as well as changes in phenotypic properties and adherence. These Dex-mediated phenotypic alterations were furthermore associated with a metabolic switch in macrophages orchestrated via PKM2. Such treated macrophages lost their ability to prevent Aspergillus fumigatus germination, which was correlated with accelerated fungal growth, destruction of macrophages, and induction of an anti-inflammatory cytokine profile. Taken together, repolarization of macrophages following corticosteroid treatment and concomitant switch to an anti-inflammatory phenotype might play a prominent role in triggering invasive aspergillosis (IA) due to suppression of innate immunological responses necessary to combat extensive fungal outgrowth.

The AXL/Gas-6 pathway as critical negative regulator of inflammation to orchestrate in human liver regeneration

Presenter: Patrick Starlinger MD | Mayo Clinic, Rochester Background: AXL and its corresponding ligand GAS-6 are critically involved in hepatic immunomodulation. Accumulating evidence further suggests their importance in regenerative processes. Essential might be their pleiotropic inhibitory effect on innate inflammatory responses, mediated by shifting macrophage phenotype from a pro-inflammatory M1 to an anti-inflammatory, pro-regenerative M2 polarization. Given experimental evidence, we aimed to assess the relevance of the AXL-pathway in human liver regeneration and, consequently, its association with clinical outcome after hepatic resection. Methods: Preoperative sAXL, GAS-6 concentrations and postoperative clinical outcome were analyzed in patients undergoing partial hepatectomy. Perioperative dynamics of interleukin (IL)-6 and neutrophil density were assessed as markers of inflammation, and sCD163, reflecting a shift in macrophage polarization. Results: Preoperatively elevated sAXL and GAS-6 levels significantly predicted postoperative liver dysfunction (area under the curve = 0.721 and 0.722; P < 0.005) and worse clinical outcome. These patients were found to be unable to respond with an immediate burst upon induction of liver regeneration. Abolished AXL pathway response interfered with sufficient formation/generation of regeneratory macrophages, as shown by a reduced increase of sCD163, an indicator of M2-polarization. Concomitantly, a distinct association of neutrophil infiltration (δ - GAS-6 and δ - Neutrophils: R = - 0.941 (P = 0.002)) and IL-6 release with an absent increase of TAM-signaling indicated pronounced postoperative inflammation. This was further supported by increased intrahepatic secondary necrosis as reflected by M65. Conclusion: We provided evidence that sAXL and GAS-6 represent not only potent and easily accessible preoperative biomarkers for the postoperative outcome, but that AXL/GAS-6 signaling is of critical relevance for human liver regeneration. Chronic exhaustion of the sAXL/GAS-6 system results in a lack of their immediate release upon induction of liver regeneration, resulting in an overwhelming immune activation, presumably due to absent M2 macrophage polarization.

Rosiglitazone Suppresses Renal Crystal Deposition by Ameliorating Tubular Injury Resulted from Oxidative Stress and Inflammatory Response via Promoting the Nrf2/HO‐1 Pathway and Shifting Macrophage Polarization

Oxidative stress and inflammatory response are closely related to nephrolithiasis. This study is aimed at exploring whether rosiglitazone (ROSI), a regulator of macrophage (Mp) polarization, could reduce renal calcium oxalate (CaOx) deposition by ameliorating oxidative stress and inflammatory response. Male C57 mice were equally and randomly divided into 7 groups. Kidney sections were collected on day 5 or day 8 after treatment. Pizzolato staining and polarized light optical microscopy were used to detect crystal deposition. PAS staining and TUNEL assay were performed to assess the tubular injury and cell apoptosis, respectively. Gene expression was assessed by immunohistochemistry, immunofluorescence, ELISA, qRT-PCR, and Western blot. The reactive oxygen species (ROS) level was assessed using a fluorescence microplate and fluorescence microscope. Hydrogen peroxide (H2O2), malonaldehyde (MDA), and glutathione (GSH) were evaluated to determine oxidative stress. Lactic dehydrogenase (LDH) activity was examined to detect cell injury. Adhesion of CaOx monohydrate (COM) crystals to HK-2 cells was detected by crystal adhesion assay. HK-2 cell death or renal macrophage polarization was assessed by flow cytometry. In vivo, renal crystal deposition, tubular injury, crystal adhesion, cell apoptosis, oxidative stress, and inflammatory response were significantly increased in the 7-day glyoxylic acid- (Gly-) treated group but were decreased in the ROSI-treated groups, especially in the groups pretreated with ROSI. Moreover, ROSI significantly reduced renal Mp aggregation and M1Mp polarization but significantly enhanced renal M2Mp polarization. In vitro, ROSI significantly suppressed renal injury, apoptosis, and crystal adhesion of HK-2 cells and markedly shifted COM-stimulated M1Mps to M2Mps, presenting an anti-inflammatory effect. Furthermore, ROSI significantly suppressed oxidative stress by promoting the Nrf2/HO-1 pathway in HK-2 cells. These findings indicate that ROSI could ameliorate renal tubular injury that resulted from oxidative stress and inflammatory response by suppressing M1Mp polarization and promoting M2Mp polarization. Therefore, ROSI is a potential therapeutic and preventive drug for CaOx nephrolithiasis.

Enterococcus faecalis shifts macrophage polarization toward M1-like phenotype with an altered cytokine profile

ABSTRACT Background: The macrophage is an innate immune defense cell involved in pathogen recognition and clearance. Aim: In view of the diversity of the macrophage phenotype and function, the present study investigated how Enterococcus faecalis infection affects the differentiation, phenotype and cytokine profile of macrophages. Methods: Murine bone marrow-derived stem cells were co-cultured with E. faecalis before and after differentiation. Macrophage M0 polarization towards M1 or M2 was initiated at day 6 by addition of LPS and INF-γ, or IL-4 and IL-13, respectively. Results: E. faecalis did not inhibit macrophage differentiation and were identified within macrophages. Viability of the macrophages infected with E. faecalis prior to differentiation was enhanced, evidenced by apoptosis inhibition, as was expression of CD38 and IRF5 proteins, indicators of M1-like polarization. These M1-like macrophages expressed an aberrant cytokine mRNA profile, with reduction in inflammatory cytokines IL-1β and IL-12 and increase in regulatory cytokine IL-10. No changes in TNF-α or TGF-β1 were detected, compared with the control groups. This atypical M1-like phenotype was retained even upon stimulation with growth factors that normally trigger their development into M2 macrophages. Conclusions: These findings suggested that E. faecalis infection of bone marrow-derived stem cells during differentiation into macrophages induces an atypical M1-like phenotype associated with intracellular bacterial survival.

Niacin and Butyrate: Nutraceuticals Targeting Dysbiosis and Intestinal Permeability in Parkinson's Disease.

Dysbiosis is implicated by many studies in the pathogenesis of Parkinson’s disease (PD). Advances in sequencing technology and computing have resulted in confounding data regarding pathogenic bacterial profiles in conditions such as PD. Changes in the microbiome with reductions in short-chain fatty acid (SCFA)-producing bacteria and increases in endotoxin-producing bacteria likely contribute to the pathogenesis of PD. GPR109A, a G-protein coupled receptor found on the surface of the intestinal epithelium and immune cells, plays a key role in controlling intestinal permeability and the inflammatory cascade. The absence of GPR109A receptors is associated with decreased concentration of tight junction proteins, leading to increased intestinal permeability and susceptibility to inflammation. In inflammatory states, butyrate acts via GPR109A to increase concentrations of tight junction proteins and improve intestinal permeability. Niacin deficiency is exacerbated in PD by dopaminergic medications. Niacin supplementation has been shown to shift macrophage polarization from pro-inflammatory to an anti-inflammatory profile. Niacin and butyrate, promising nutrients and unique ligands for the G protein-coupled receptor GPR109A, are reviewed in this paper in detail.

Inducing regulated necrosis and shifting macrophage polarization with anti-EMMPRIN antibody (161-pAb) and complement factors.

Treatment of solid tumors is often hindered by an immunosuppressive tumor microenvironment (TME) that prevents effector immune cells from eradicating tumor cells and promotes tumor progression, angiogenesis, and metastasis. Therefore, targeting components of the TME to restore the ability of immune cells to drive anti‐tumoral responses has become an important goal. One option is to induce an immunogenic cell death (ICD) of tumor cells that would trigger an adaptive anti‐tumoral immune response. Here we show that incubating mouse renal cell carcinoma (RENCA) and colon carcinoma cell lines with an anti‐extracellular matrix metalloproteinase inducer polyclonal antibody (161‐pAb) together with complement factors can induce cell death that inhibits caspase‐8 activity and enhances the phosphorylation of receptor‐interacting protein kinase 3 (RIPK3) and mixed‐lineage kinase‐like domain (MLKL). This regulated necrotic death releases high levels of dsRNA molecules to the conditioned medium (CM) relative to the necrotic death of tumor cells induced by H2O2 or the apoptotic death induced by etoposide. RAW 264.7 macrophages incubated with the CM derived from these dying cells markedly enhanced the secretion of IFNβ, and enhanced their cytotoxicity. Furthermore, degradation of the dsRNA in the CM abolished the ability of RAW 264.7 macrophages to secrete IFNβ, IFNγ‐induced protein 10 (IP‐10), and TRAIL. When mice bearing RENCA tumors were immunized with the 161‐pAb, their lysates displayed elevated levels of phosphorylated RIPK3 and MLKL, as well as increased concentrations of dsRNA, IFNβ, IP‐10, and TRAIL. This shows that an antigen‐targeted therapy using an antibody and complement factors that triggers ICD can shift the mode of macrophage activation by triggering regulated necrotic death of tumor cells.

In vitro and in vivo evaluation of anti-tumoral effect of M1 phenotype induction in macrophages by miR-130 and miR-33 containing exosomes.

In the tumor microenvironment, macrophages polarize into the M2 phenotype to facilitate tumorigenesis. Tumor-derived exosomes can act as mediators between the tumor microenvironment and stromal cells by transporting proteins, mRNAs, and miRNAs. Exosomal miRNAs play a pivotal role in modulating tumor microenvironment and macrophage polarization. Here, we overexpressed miR-130 and miR-33 in exosomes of MDA-MB-231 cells and investigated their effect on macrophage polarization and tumor progression. For this purpose, exosomes were extracted from MDA-MB-231 cells and characterized using dynamic light scattering, electron microscopy, and western blotting of exosomal markers. Then, miR-130 or miR-33 containing exosomes were used to treat IL4-induced M2 or tumor-associated macrophages (TAMs). After treatment, the polarization status of macrophages, including the expression of M1 specific genes, and the secretion of cytokines were evaluated. Finally, the conditioned medium from exosome-treated macrophages was incubated with cancer cells to evaluate its effect on the migration and invasion ability of cancer cells and, in vivo experiments investigated the effect of exosome-treated macrophages on breast cancer progression. Exosomes characterization results approved the range of size and homogeneity of extracted exosomes. Overexpression of miR-130 and miR-33 in exosomes increased the expression of M1 signature genes (IRF5, MCP1, CD80) and secretion of cytokines (IL-1β and TNF-α) as well as yeast phagocytic activity of macrophages. Besides, the conditioned medium of macrophages treated with miRNA containing exosomes declined the migration and invasion ability of cancer cells. The in vivo results indicated the inhibitory effect of exosome-treated macrophages on tumor growth. Furthermore, the results showed that in response to exosome-treated macrophages, the production of TNF-α by spleen cells increased, while the production of IL-10 and TGF-β by these cells decreased. These findings suggest that overexpression of miR-130 and miR-33 in exosomes can decrease tumor progression by shifting macrophage polarization from M2 to M1 phenotype and can be a potential therapeutic strategy for tumor interventions.

Interleukin-22 regulating Kupffer cell polarization through STAT3/Erk/Akt crosstalk pathways to extenuate liver fibrosis

AimsInterleukin (IL)-22 activates multiple signaling pathways to exert anti-inflammatory effects, but few studies have examined whether and how IL-22 may shift macrophage polarization between M1 (pro-inflammatory) and M2 (anti-inflammatory) states and thereby influence the progression of hepatic fibrosis. Main methodsUtilized CCl4 to induce liver fibrosis in mice, detected the role of IL-22 in inhibiting liver fibrosis by regulating Kupffer cells (KCs) polarization in vivo and in vitro. U937 cells were used to confirm the mechanism of IL-22 regulating macrophage polarization via the STAT3/Erk/Akt pathways. Human liver specimens were collected to verify the correlation between the levels of IL-22 and KCs during liver fibrogenesis. Key findingsDuring CCl4-induced liver fibrosis progression in mice, adding exogenous IL-22 significantly inhibited pro-fibrogenic and macrophage phenotype-altering factors secreted by M1-KCs, and it increased the number of M2-KCs. In co-cultures of hepatic stellate cells and KCs from mice treated with IL-22, a high M2/M1-KCs ratio inhibited collagen production and stellate cell activation. These results suggest that IL-22 can increase the ratio of M2-KCs to M1-KCs and thereby attenuate the progression of liver fibrosis. Mechanistic studies in vitro showed that IL-22 promoted polarization of lipopolysaccharide-treated U937 macrophages from M1 to M2. The cytokine exerted these effects by activating the STAT3 pathway while suppressing Erk1/2 and Akt pathways. Furthermore, immunofluorescent staining in human liver specimens confirmed that IL-22 levels positively correlated with the number of M2-KCs during liver fibrogenesis. SignificanceIL-22 regulates the STAT3/Erk/Akt to increase the M2/M1-KCs ratio and thereby slow liver fibrogenesis.

Laryngopharyngeal Reflux Alters Macrophage Polarization in Human Papilloma Virus-Negative Squamous Cell Carcinoma of the Larynx in Males.

Among various cells of tumor immune microenvironment (TIME) macrophages have been shown to play a pivotal role in the prognosis of many malignancies including laryngeal squamous cell carcinoma (LSCC). Laryngopharyngeal reflux (LPR) is associated with LSCC and can impact its prognosis. Local factors, particularly pH, can affect cancer growth by altering TIME and tumor associated macrophages phenotype. However, it is still unknown whether and how LPR affects TIME and macrophages polarization in LSCC. In this study we compared macrophage polarization in LSCC of patients with and without coexisting LPR. A total of 63 patients with T1-2 LSCC without (the 1st group, 30 patients) and with coexisting LPR (the 2nd group, 33 patients) were enrolled in the study. Only HPV-negative cases of males were included in the study. Immunohistochemistry was performed to visualize CD68 and CD163 macrophages. The number of macrophages was counted at the central tumor clusters (TC), peritumor stroma (TS) and at the intact laryngeal mucosa (IM) taken from the tumor-negative edge. Samples of the 2nd group patients with LSCC and LPR demonstrated significantly (P<0.05) higher inflammatory infiltration of all the evaluated compartments (TC, TS and IM). CD68+ cells count was comparable in TC and IM of the 1st and the 2nd group patients. In contrast, CD163+ cells were more numerous in the 2nd group patients in TC, TS and IM (P<0.001). Moreover, the number of M2 macrophages was significantly higher than M1 macrophages in patients with coexisting LPR. As a result, CD163/CD68 ratio was significantly (P<0.001) higher in LSCC with coexisting LPR. LPR is associated with altered macrophages polarization and increase of M2-type macrophages in LSCC. The shift in macrophage polarization towards the M2 type in patients with LPR could facilitate LSCC development and progression.

Treatment with a DC-SIGN ligand reduces macrophage polarization and diastolic dysfunction in the aging female but not male mouse hearts

Cardiac diastolic dysfunction in aging arises from increased ventricular stiffness caused by inflammation and interstitial fibrosis. The diastolic dysfunction contributes to heart failure with preserved ejection fraction (HFpEF), which in the aging population is more common in women. This report examines its progression over 12 weeks in aging C57BL/6J mice and correlates its development with changes in macrophage polarization and collagen deposition.Aged C57BL/6J mice were injected with dendritic cell–specific intercellular adhesion molecule-3-grabbing nonintegrin (DC-SIGN) ligand 1 (DCSL1, an anti-inflammatory agent) or saline for 12 weeks. Echo and Doppler measurements were performed before and after 4 and 12 weeks of treatment. DCSL1 prevented the worsening of diastolic dysfunction over time in females but not in males. Cardiac single cell suspensions analyzed by flow cytometry revealed changes in the inflammatory infiltrate: (1) in males, there was an increased total number of leukocytes with an increased pro-inflammatory profile compared with females and they did not respond to DCSL1; (2) by contrast, DCSL1 treatment resulted in a shift in macrophage polarization to an anti-inflammatory phenotype in females. Notably, DCSL1 preferentially targeted tumor necrosis factor-α (TNFα+) pro-inflammatory macrophages. The reduction in pro-inflammatory macrophage polarization was accompanied by a decrease in collagen content in the heart.Age-associated diastolic dysfunction in mice is more severe in females and is associated with unique changes in macrophage polarization in cardiac tissue. Treatment with DCSL1 mitigates the changes in inflammation, cardiac function, and fibrosis. The characteristics of diastolic dysfunction in aging female mice mimic similar changes in aging women.