CXCL7-induced macrophage infiltration in lung tumor is independent of CXCR2 expression: CXCL7-induced macrophage chemotaxis in LLC tumors

Chemokines play diverse roles in modulating the immune response during tumor development. Levels of CXC chemokine ligand 7 (CXCL7) protein vary during tumorigenesis, and the evidence suggests that this chemokine serves as a novel biomarker of early-stage lung cancer. We investigated the effect of CXCL7 gene expression on the infiltration of myeloid cells into the tumor microenvironment in Lewis lung carcinoma (LLC). Tumors established from LLC cells overexpressing CXCL7 (CXCL7-LLC tumors) increased the infiltration of CD206⁺ M2 macrophages at the early stages of tumorigenesis. This infiltration was independent of CXCR2 expression on either tumor cells or macrophages. CXCL7-LLC tumors developed faster than control-LLC tumors (IRES-LLC tumor) did. The extent of CD4⁺ T cell, CD8⁺ T cell, and natural killer T cell infiltration was similar between the two tumor groups. Our findings suggest that CXCL7 attracts macrophages especially at the tumor site and may accelerate lung tumor development in the early stages.     

Human lung fibroblasts inhibit macrophage inflammatory protein-1alpha production by lipopolysaccharide-stimulated macrophages

We investigated the effect of interaction between lung fibroblasts and macrophages on macrophage inflammatory protein 1alpha (MIP-1alpha) production by macrophages. In a co-culture system consisting of WI-38 lung fibroblasts layered over THP-1 macrophages stimulated with lipopolysaccharide (LPS), MIP-1alpha production by THP-1 was significantly lower in co-culture with WI-38 than in THP-1 alone. Treatment with conditioned medium generated from WI-38 (CM-WI-38) suppressed MIP-1alpha production and mRNA expression in THP-1 cells. Such inhibitory effect of CM-WI-38 on MIP-1alpha production was abrogated by treatment with indomethacin, NS-398 (a specific COX-2 inhibitor), or anti-prostaglandin E(2) antibody. Furthermore, even in a transwell filter system separating both types of cells, co-culture-induced reduction of MIP-1alpha production was observed. Therefore, soluble factors such as prostaglandin E(2) released from lung fibroblasts are responsible for the co-culture-induced inhibition of macrophage-derived MIP-1alpha production, suggesting that immune and inflammatory cell interactions can contribute to the modulatory mechanisms involved in the regulation of the inflammatory or fibrotic process.     

IL-10 is required for polarization of macrophages to M2-like phenotype by mycobacterial DnaK (heat shock protein 70)

Macrophages are key cells in the innate immune system. They phagocytose pathogens and cellular debris, promote inflammation, and have important roles in tumor immunity. Depending on the microenvironment, macrophages can polarize to M1 (inflammatory) or M2 (anti-inflammatory) phenotypes. Extracellular DnaK (the bacterial ortholog of the mammalian Hsp70) from Mycobacterium tuberculosis (Mtb) was described to exert immune modulatory roles in an IL-10 dependent manner. We have previously observed that endotoxin-free DnaK can polarize macrophages to an M2-like phenotype. However, the mechanisms that underlie this polarization need to be further investigated. IL-10 has been described to promote macrophage polarization, so we investigated the involvement of this cytokine in macrophages stimulated with extracellular DnaK. IL-10 was required to induce the expression of M2 markers - Ym1 and Fizz, when macrophages were treated with DnaK. Blockade of IL-10R also impaired DnaK induced polarization, demonstrating the requirement of the IL-10/IL-10R signaling pathway in this polarization. DnaK was able to induce TGF-β mRNA in treated macrophages in an IL-10 dependent manner. However, protein TGF-β could not be detected in culture supernatants. Finally, using an in vivo allogeneic melanoma model, we observed that DnaK-treated macrophages can promote tumor growth in an IL-10-dependent manner. Our results indicate that the IL-10/IL-10R axis is required for DnaK-induced M2-like polarization in murine macrophages.     

Macrophage cell morphology-imprinted substrates can modulate mesenchymal stem cell behaviors and macrophage M1/M2 polarization for wound healing applications

Mesenchymal stem cells and macrophages (MQ) are two very important cells involved in the normal wound healing process. It is well understood that topological cues and mechanical factors can lead to different responses in stem cells and MQ by influencing their shape, cytoskeleton proliferation, migration, and differentiation, which play an essential role in the success or failure of biomaterial implantation and more importantly wound healing. On the other hand, the polarization of MQ from proinflammatory (M1) to prohealing (M2) phenotypes has a critical role in the acceleration of wound healing. In this study, the morphology of different MQ subtypes (M0, M1, and M2) was imprinted on a silicon surface (polydimethylsiloxane [PDMS]) to prepare a nano-topography cell-imprinted substrate with the ability to induce anti-inflammatory effects on the mouse adipose-derived stem cells (ADSCs) and RAW264.7 monocyte cell line (MO). The gene expression profiles and flow cytometry of MQ revealed that the cell shape microstructure promoted the MQ phenotypes according to the specific shape of each pattern. The ELISA results were in agreement with the gene expression profiles. The ADSCs on the patterned PDMS exhibited remarkably different shapes from no-patterned PDMS. The MOs grown on M2 morphological patterns showed a significant increase in expression and section of anti-inflammatory cytokine compared with M0 and M1 patterns. The ADSCs homing in niches heavily deformed the cytoskeletal, which is probably why the gene expression and phenotype unexpectedly changed. In conclusion, wound dressings with M2 cell morphology-induced surfaces are suggested as excellent anti-inflammatory and antiscarring dressings.     

JNK suppresses pulmonary fibroblast elastogenesis during alveolar development

Background

The formation of discrete elastin bands at the tips of secondary alveolar septa is important for normal alveolar development, but the mechanisms regulating the lung elastogenic program are incompletely understood. JNK suppress elastin synthesis in the aorta and is important in a host of developmental processes. We sought to determine whether JNK suppresses pulmonary fibroblast elastogenesis during lung development.

Methods

Alveolar size, elastin content, and mRNA of elastin-associated genes were quantitated in wild type and JNK-deficient mouse lungs, and expression profiles were validated in primary lung fibroblasts. Tropoelastin protein was quantitated by Western blot. Changes in lung JNK activity throughout development were quantitated, and pJNK was localized by confocal imaging and lineage tracing.

Results

By morphometry, alveolar diameters were increased by 7% and lung elastin content increased 2-fold in JNK-deficient mouse lungs compared to wild type. By Western blot, tropoelastin protein was increased 5-fold in JNK-deficient lungs. Postnatal day 14 (PND14) lung JNK activity was 11-fold higher and pJNK:JNK ratio 6-fold higher compared to PN 8 week lung. Lung tropoelastin, emilin-1, fibrillin-1, fibulin-5, and lysyl oxidase mRNAs inversely correlated with lung JNK activity during alveolar development. Phosphorylated JNK localized to pulmonary lipofibroblasts. PND14 JNK-deficient mouse lungs contained 7-fold more tropoelastin, 2,000-fold more emilin-1, 800-fold more fibrillin-1, and 60-fold more fibulin-5 than PND14 wild type lungs. Primarily lung fibroblasts from wild type and JNK-deficient mice showed similar differences in elastogenic mRNAs.

Conclusions

JNK suppresses fibroblast elastogenesis during the alveolar stage of lung development.     

RBP-J is required for M2 macrophage polarization in response to chitin and mediates expression of a subset of M2 genes

Development of alternatively activated (M2) macrophage phenotypes is a complex process that is coordinately regulated by a plethora of pathways and factors. Here, we report that RBP-J, a DNA-binding protein that integrates signals from multiple pathways including the Notch pathway, is critically involved in polarization of M2 macrophages. Mice deficient in RBP-J in the myeloid compartment exhibited impaired M2 phenotypes in vivo in a chitin-induced model of M2 polarization. Consistent with the in vivo findings, M2 polarization was partially compromised in vitro in Rbpj-deficient macrophages as demonstrated by reduced expression of a subset of M2 effector molecules including arginase 1. Functionally, myeloid Rbpj deficiency impaired M2 effector functions including recruitment of eosinophils and suppression of T cell proliferation. Collectively, we have identified RBPJ as an essential regulator of differentiation and function of alternatively activated macrophages.     

S100-β aggravates spinal cord injury via activation of M1 macrophage phenotype

Objectives:S100-β has been identified as a sensitive biomarker in central nervous system injuries. However, the functions and mechanisms of S100-β are unknown in spinal cord injury.Methods:Spinal cord injury (SCI) mouse model was generated by surgical operation, microglia activation model was established by inducing BV-2 cells with LPS. The SCI model was evaluated by Basso-Beattie-Bresnahan (BBB) behavioral score, HE staining, and Nissl staining. The expression level of S100-β was detected by qRT-PCR, western blot, and immunofluorescence. qRT-PCR and western blot were used to detect the expression of iNOS and CD16. Pro-inflammatory cytokines TNF-α and IL-1β levels were detected by qRT-PCR and ELISA.Results:The expression of IL-1β, TNF-α, iNOS, and CD16 increased at 3^rd day after SCI. In BV2 microglia, LPS treatment promoted the expression of S100-β, IL-1β, TNF-α, iNOS, and CD16. Knockdown of S100-β reduced the expression of iNOS stimulated by LPS. Over-expression of S100-β increased IL-1β and TNF-α, and S100-β inhibition suppressed IL-1β and TNF-α. In SCI mice, knockdown of S100-β attenuated the spinal cord injury and inhibited the expression of iNOS, IL-1β, and TNF-α.Conclusions:Down-regulation of S100-β could inhibit the pathogenesis of SCI and inhibit the activation of M1 macrophages. S100-β may be a useful diagnostic biomarker or therapeutic target for SCI.     

Exercise-induced enhancement of insulin sensitivity is associated with accumulation of M2-polarized macrophages in mouse skeletal muscle

Exercise enhances insulin sensitivity in skeletal muscle, but the underlying mechanism remains obscure. Recent data suggest that alternatively activated M2 macrophages enhance insulin sensitivity in insulin target organs such as adipose tissue and liver. Therefore, the aim of this study was to determine the role of anti-inflammatory M2 macrophages in exercise-induced enhancement of insulin sensitivity in skeletal muscle. C57BL6J mice underwent a single bout of treadmill running (20 m/min, 90 min). Twenty-four hours later, ex vivo insulin-stimulated 2-deoxy glucose uptake was found to be increased in plantaris muscle. This change was associated with increased number of CD163-expressing macrophages (i.e. M2-polarized macrophages) in skeletal muscle. Systemic depletion of macrophages by pretreatment of mice with clodronate-containing liposome abrogated both CD163-positive macrophage accumulation in skeletal muscle as well as the enhancement of insulin sensitivity after exercise, without affecting insulin-induced phosphorylation of Akt and AS160 or exercise-induced GLUT4 expression. These results suggest that accumulation of M2-polarized macrophages is involved in exercise-induced enhancement of insulin sensitivity in mouse skeletal muscle, independently of the phosphorylation of Akt and AS160 and expression of GLUT4.     

uPARAP expression during murine lung development

Lung remodeling requires active collagen deposition and degradation. Urokinase plasminogen activator receptor-associated protein (uPARAP), or Endo 180, is a cell-surface receptor for collagens, which leads to collagen internalization and degradation. Thus, uPARAP-mediated collagen degradation is an additional pathway for matrix remodeling in addition to matrix remodeling mediated by matrix metalloproteinases and cathepsins. Using immunohistochemistry, we demonstrate extensive uPARAP expression in the mesenchyme throughout murine lung development. By immunofluorescence, we demonstrate significant overlap of uPARAP expression with collagen IV expression, but minimal overlap with collagen I expression in the developing murine lung. Finally, we compared lung development between wild-type and uPARAP(-/-) mice, and found no significant histologic differences, indicating the presence of alternative collagen degradation pathways during murine lung development.     

Endoplasmic reticulum stress controls M2 macrophage differentiation and foam cell formation

Macrophages are essential in atherosclerosis progression, but regulation of the M1 versus M2 phenotype and their role in cholesterol deposition are unclear. We demonstrate that endoplasmic reticulum (ER) stress is a key regulator of macrophage differentiation and cholesterol deposition. Macrophages from diabetic patients were classically or alternatively stimulated and then exposed to oxidized LDL. Alternative stimulation into M2 macrophages lead to increased foam cell formation by inducing scavenger receptor CD36 and SR-A1 expression. ER stress induced by alternative stimulation was necessary to generate the M2 phenotype through JNK activation and increased PPARγ expression. The absence of CD36 or SR-A1 signaling independently of modified cholesterol uptake decreased ER stress and prevented the M2 differentiation typically induced by alternative stimulation. Moreover, suppression of ER stress shifted differentiated M2 macrophages toward an M1 phenotype and subsequently suppressed foam cell formation by increasing HDL- and apoA-1-induced cholesterol efflux indicating suppression of macrophage ER stress as a potential therapy for atherosclerosis.     

Disruption of the TIMP-1 gene product is associated with accelerated endometrial gland formation during early postnatal uterine development

Postnatal uterine development is marked by periods of tissue remodeling. The objective of the present study was to examine the role of tissue inhibitor of metalloproteinase-1 (TIMP-1), a regulator of tissue remodeling events, during postnatal uterine development and to assess the phenotypic consequences of disruption of the TIMP-1 gene product during this time period. To accomplish this goal, wild-type and TIMP-1 null mice were sacrificed at Postnatal Days (PNDs) 5, 10, 15, 20, and 25 and uterine morphology, TIMP expression and matrix metalloproteinase (MMP) activity were assessed. In wild-type mice, TIMP-1 mRNA steady-state levels were highest at PND 5, after which expression decreased. TIMP-2 and TIMP-3 expression in wild-type mice showed no significant changes from PND 5 to 25. In TIMP-1 null mice, TIMP-2 and TIMP-3 expression patterns were similar to those in wild-type counterparts with the exception that, at PND 10, TIMP-2 and TIMP-3 expression was significantly lower in the null mice. Endometrial gland number and uterine histology were similar between genotypes at PNDs 5 and 10, but at PNDs 15 and 20, endometrial glands were more abundant in TIMP-1 null mice. Associated with the increased gland density in the null mice was an increase in total MMP activity above the levels expressed in wild-type mice. In summary, disruption of the TIMP-1 gene product is associated with reduced TIMP-2 and TIMP-3 steady-state mRNA levels, elevated MMP activity, and accelerated endometrial gland formation. We conclude that, during early postnatal uterine development, TIMP-1 may be critical for proper endometrial gland development.     

BST2 induced macrophage M2 polarization to promote the progression of colorectal cancer

Background: Tumor-associated macrophages (TAMs) are one of the most prominent tumor-infiltrating immune cells in the tumor microenvironment (TME) of CRC and play a vital role in the progression of CRC. BST2 was predicted to be associated with the infiltration of TAMs. However, its potential function by which CRC cells and TAMs interact with each other still needs further investigation.Methods: The target genes in CRC were selected by bioinformatics screening. The level of bone marrow stromal cell antigen 2 (BST2) in CRC cells and tissues was determined by qRT‒PCR, Western blotting, and immunohistochemistry staining. In vitro and in vivo assays were applied to clarify the function of BST2.Results: In this study, according to bioinformatics analysis, a nomogram based on the risk score (constructed by BST2 and CAV1 (caveolin-1)) and clinical features was built and displayed satisfactory prognostic value. Upregulated BST2 was significantly related to Braf mutation, dMMR/MSI-H, CMS1 subtype, and immune response and was a potential biomarker for predicting immune checkpoint blockade therapy. Silencing BST2 in CRC obviously restrained CRC progression and M2 TAM polarization. The infiltration of TAMs was positively correlated with the high expression of BST2, and depletion of TAMs alleviated the protumoural effect of BST2 in CRC in vivo. In vitro experiments revealed that a reduction in BST2 in CRC inhibited CRC proliferation and migration and also M2 polarization.Conclusion: These findings indicated that BST2 played a vital role in CRC progression and might be a predictable marker for immunotherapy.     

Peculiarities of proteasome pool formation in rat spleen and liver during postnatal development

Changes in the specific activity and amounts of 26S and 20S proteasome pools in rat spleen and liver during postnatal development and appearance in them of immune subunits were studied. Two decreases in chymotrypsin-like activity of the proteasome pools were recorded during the first three weeks after birth. The activity minimum fell on the 11th and 19th days, and the first decrease was more prolonged and pronounced than the second. The decrease in the specific activity of the 26S proteasome pools was associated with a reduction of their quantity. The 20S proteasome pools displayed no such decreases. Noticeable quantities of immune subunits LMP7 and LMP2 were revealed by Western blotting in the spleen on the 7th day and on the 19th day in the liver, concurrently with the beginning of the decrease in the proteasome activity. It was concluded that during the first three weeks of postnatal development the proteasome pools in rat spleen and liver were replaced twice, and in the spleen (a lymphoid organ) a qualitatively new pool containing immune subunits appeared nearly two weeks earlier than in the liver (a non-lymphoid organ). The appearance of immune proteasomes in different organs and tissues during some weeks after birth seems to explain the immune system inefficiency during embryogenesis and early postnatal development.     

Prenatal exposure to thyroid hormone is necessary for normal postnatal development of murine heart and lungs

Maternal hypothyroxinemia during early pregnancy poses an increased risk for poor neuropsychological development of the fetus. We tested the hypothesis that maternal hypothyroidism before the onset of fetal thyroid function also affects postnatal development of heart and lungs. This question was addressed in transgenic mice that express herpes simplex virus thymidine kinase in their thyroidal follicle cells. Treatment with ganciclovir rendered these mice severely hypothyroid because viral thymidine kinase converts ganciclovir into a cytotoxic nucleoside analog. Since ganciclovir crosses the placenta, it also destroyed the thyroid of transgenic embryos while leaving the thyroids of nontransgenic littermates unaffected. Hypothyroidism of both mother and fetus did not affect prenatal heart and lung development. However, the postnatal switch from beta- to alpha-myosin heavy chain (beta- and alpha-MHC, respectively) gene expression and the increase of SERCA-2a mRNA expression did not occur in the ventricular myocardium of either the transgenic (thyroid destroyed) or nontransgenic (intact thyroid) offspring of hypothyroid mothers. Similarly, postnatal animals of the latter two groups retained elevated surfactant protein (SP) A, B, and C mRNA levels in their alveolar epithelium. In hypothyroid pups from hypothyroid mothers, these changes were accompanied by decreased alveolar septation. Our study shows that these effects of maternal hypothyroidism become manifest after birth and are aggravated by the concomitant existence of neonatal hypothyroidism.     

Contrasting effects of stanniocalcin-related polypeptides on macrophage foam cell formation and vascular smooth muscle cell migration

Stanniocalcin (STC) is a calcium- and phosphate-regulating hormone secreted by the corpuscles of Stannius, an endocrine gland of bony fish. Its human homologues, STC1 and STC2 showing 34% amino acid identity each other, are expressed in a variety of human tissues. To clarify their roles in atherosclerosis, we investigated the effects of their full-length proteins, STC1(18–247) and STC2(25–302), and STC2-derived fragment peptides, STC2(80–100) and STC2(85–99), on inflammatory responses in human umbilical vein endothelial cells (HUVECs), human macrophage foam cell formation, the migration and proliferation of human aortic smooth muscle cells (HASMCs) and the extracellular matrix expression. All these polypeptides suppressed lipopolysaccharide-induced expressions of interleukin-6, monocyte chemotactic protein-1, and intercellular adhesion molecule-1 in HUVECs. Oxidized low-density lipoprotein-induced foam cell formation was significantly decreased by STC1(18–247) and increased by STC2(80–100) and STC2(85–99), but not STC2(25–302), in human macrophages. Expression of acyl-CoA:cholesterol acyltransferase-1 (ACAT1) was significantly suppressed by STC1(18–247) but stimulated by STC2(80–100) and STC2(85–99). Expression of ATP-binding cassette transporter A1 was significantly stimulated by STC1(18–247). Neither STC1(18–247) nor STC2-derived peptides significantly affected CD36 expression in human macrophages or HASMC proliferation. STC2(80–100) and STC2(85–99) significantly increased HASMC migration, whereas STC1(18–247) significantly suppressed the angiotensin II-induced HASMC migration. Expressions of collagen-1, fibronectin, matrix metalloproteinase-2, and elastin were mostly unchanged with the exception of fibronectin up-regulation by STC2(80–100). Our results demonstrated the contrasting effects of STC1 and STC2-derived peptides on human macrophage foam cell formation associated with ACAT1 expression and on HASMC migration. Thus, STC-related polypeptides could serve as a novel therapeutic target for atherosclerosis.