Chemokine-Induced Macrophage Polarization in Inflammatory Conditions

NCOA5 Haploinsufficiency in Myeloid-Lineage Cells Sufficiently Causes Nonalcoholic Steatohepatitis and Hepatocellular Carcinoma

BACKGROUND & AIMS

The nuclear receptor coactivator 5 (NCOA5) is a putative type 2 diabetes susceptibility gene. NCOA5 haploinsufficiency results in the spontaneous development of nonalcoholic fatty liver disease (NAFLD), insulin resistance, and hepatocellular carcinoma (HCC) in male mice; however, the cell-specific effect of NCOA5 haploinsufficiency in various types of cells, including macrophages, on the development of NAFLD and HCC remains unknown.

METHODS

Control and myeloid-lineage-specific Ncoa5 deletion (Ncoa5ΔM/+) mice fed a normal diet were examined for the development of NAFLD, nonalcoholic steatohepatitis (NASH), and HCC. Altered genes and signaling pathways in the intrahepatic macrophages of Ncoa5ΔM/+ male mice were analyzed and compared with those of obese human individuals. The role of platelet factor 4 (PF4) in macrophages and the underlying mechanism by which PF4 affects NAFLD/NASH were explored in vitro and in vivo. PF4 expression in HCC patient specimens and prognosis was examined.

RESULTS

Myeloid-lineage-specific Ncoa5 deletion sufficiently causes spontaneous NASH and HCC development in male mice fed a normal diet. PF4 overexpression in Ncoa5ΔM/+ intrahepatic macrophages is identified as a potent mediator to trigger lipid accumulation in hepatocytes by inducing lipogenesis-promoting gene expression. The transcriptome of intrahepatic macrophages from Ncoa5ΔM/+ male mice resembles that of obese human individuals. High PF4 expression correlated with poor prognosis of HCC patients and increased infiltrations of M2 macrophages, regulatory T cells, and myeloid-derived suppressor cells in HCCs.

CONCLUSIONS

Our findings reveal a novel mechanism for the onset of NAFLD/NASH and HCC initiated by NCOA5-deficient macrophages, suggesting the NCOA5-PF4 axis in macrophages as a potential target for developing preventive and therapeutic interventions against NAFLD/NASH and HCC.

Variants in transient receptor potential channels and toll-like receptors modify airway responses to allergen and air pollution: a randomized controlled response human exposure study

BACKGROUND

Environmental co-exposure to allergen and traffic-related air pollution is common globally and contributes to the exacerbation of respiratory diseases. Individual responses to environmental insults remain variable due to gene-environment interactions.

OBJECTIVE

This study examined whether single nucleotide polymorphisms (SNPs) in lung cell surface receptor genes modifies lung function change and immune cell recruitment in allergen-sensitized individuals exposed to diesel exhaust (DE) and allergen.

METHODS

In this randomized, double-blinded, four-arm, crossover study, 13 allergen-sensitized participants underwent allergen inhalation challenge following a 2-hour exposure to DE, particle-depleted diesel exhaust (PDDE) or filtered air (FA). Lung function tests and bronchoscopic sample collection were performed up to 48 h after exposures. Transient receptor potential channel (TRPA1 and TRPV1) and toll-like receptor (TLR2 and TLR4) risk alleles were used to construct an unweighted genetic risk score (GRS). Exposure-by-GRS interactions were tested using mixed-effects models.

RESULTS

In participants with high GRS, allergen exposure was associated with an increase in airway hyperresponsiveness (AHR) when co-exposed to PDDE (p = 0.03) but not FA or DE. FA and PDDE also were associated with a relative increase in macrophages and decrease in lymphocytes in bronchoalveolar lavage.

CONCLUSIONS

TRPs and TLRs variants are associated with increased AHR and altered immune cellularity in allergen-exposed individuals. This effect is blunted by DE exposure, suggesting greater influence of unmeasured gene variants as primary meditators of a particulate-rich co-exposure.

TRIAL REGISTRATION

The study was registered with ClinicalTrials.gov on December 20, 2013 (NCT02017431).

Manganese-Implanted Titanium Modulates the Crosstalk between Bone Marrow Mesenchymal Stem Cells and Macrophages to Improve Osteogenesis

Manganese (Mn) is an essential micronutrient in various physiological processes, but its functions in bone metabolism remain undefined. This is partly due to the interplay between immune and bone cells because Mn plays a central role in the immune system. In this study, we utilized the plasma immersion ion implantation and deposition (PIII&D) technique to introduce Mn onto the titanium surface. The results demonstrated that Mn-implanted surfaces stimulated the shift of macrophages toward the M1 phenotype and had minimal effects on the osteogenic differentiation of mouse bone marrow mesenchymal stem cells (mBMSCs) under mono-culture conditions. However, they promoted the M2 polarization of macrophages and improved the osteogenic activities of mBMSCs under co-culture conditions, indicating the importance of the crosstalk between mBMSCs and macrophages mediated by Mn in osteogenic activities. This study provides a positive incentive for the application of Mn in the field of osteoimmunology.

JMJD6 in tumor-associated macrophage regulates macrophage polarization and cancer progression via STAT3/IL-10 axis

The tumor-associated macrophage (TAM) is the most abundant group of immune cells in the tumor microenvironment (TME), which plays a critical role in the regulation of tumor progression and treatment resistance. Based on different polarization status, TAMs may also induce antitumor immune responses or immunosuppression. The present study identified JMJD6 (Jumonji domain-containing 6) as a novel modulator of TAM activation, the upregulation of which was associated with the immunosuppressive activities of TAMs. JMJD6 deficiency attenuated the growth of both Lewis lung carcinoma (LLC) tumors and B16F10 melanomas by reversing M2-like activation of macrophages, and sensitized tumors to immune checkpoint blockades (ICBs). Moreover, the JMJD6-induced inhibition of M2 polarization was potentially mediated by the STAT3/IL-10 signaling. These findings highlight the regulatory activities of JMJD6 in TAM polarization, and the therapeutic potential of JMJD6/STAT3/IL-10 axis blockades to enhance the efficacy of ICBs in cancer treatment.

Low CCL2 and CXCL8 Production and High Prevalence of Allergies in Children with Microcephaly Due to Congenital Zika Syndrome

Congenital Zika Syndrome (CZS) is associated with an increased risk of microcephaly in affected children. This study investigated the peripheral dysregulation of immune mediators in children with microcephaly due to CZS. Gene expression quantified by qPCR in whole blood samples showed an increase in IFNγ and IL-13 transcripts in children affected with microcephaly compared to the control group. The microcephaly group exhibited significantly decreased CCL2 and CXCL8 levels in serum, quantified by CBA assay. An allergic profile questionnaire revealed a high prevalence of allergies in the microcephaly group. In accordance, elevated serum IgE level measured by the Proquantum Immunoassay was observed in children affected with microcephaly compared to the control group. Altogether, these findings show a persistent systemic inflammation in children with microcephaly due to CZS and suggest a possible impairment in leukocyte migration caused by low production of CCL2 and CXCL8, in addition to high levels of IgE associated with high prevalence of allergies. The dysregulation of inflammatory genes and chemokines underscores the importance of understanding the immunological characteristics of CZS. Further investigation into the long-term consequences of systemic inflammation in these children is crucial for developing appropriate therapeutic strategies and tailored vaccination protocols.

Interplay of Chemokines Receptors, Toll-like Receptors, and Host Immunological Pathways

A comprehensive framework has been established for understanding immunological pathways, which can be categorized into eradicated and tolerable immune responses. Toll-like receptors (TLRs) are associated with specific immune responses. TH1 immunity is related to TLR7, TLR8, and TLR9, while TH2 immunity is associated with TLR1, TLR2, and TLR6. TH22 immunity is linked to TLR2, TLR4, and TLR5, and THαβ (Tr1) immunity is related to TLR3, TLR7, and TLR9. The chemokine receptor CXCR5 is a marker of follicular helper T cells, and other chemokine receptors can also be classified within a framework based on host immunological pathways. On the basis of a literature review on chemokines and immunological pathways, the following associations were identified: CCR5 with TH1 responses, CCR1 with TH1-like responses, CCR4 (basophils) and CCR3 (eosinophils) with TH2 and TH9 responses, CCR10 with TH22 responses, CCR6 with TH17 responses, CXCR3 with THαβ responses, CCR8 with regulatory T cells (Treg), and CCR2 with TH3 responses. These findings contribute to the identification of biomarkers for immune cells and provide insights into host immunological pathways. Understanding the chemokine and Toll-like receptor system is crucial for comprehending the function of the innate immune system, as well as adaptive immune responses.

The role of macrophages polarization in sepsis-induced acute lung injury

Sepsis presents as a severe infectious disease frequently documented in clinical settings. Characterized by its systemic inflammatory response syndrome, sepsis has the potential to trigger multi-organ dysfunction and can escalate to becoming life-threatening. A common fallout from sepsis is acute lung injury (ALI), which often progresses to acute respiratory distress syndrome (ARDS). Macrophages, due to their significant role in the immune system, are receiving increased attention in clinical studies. Macrophage polarization is a process that hinges on an intricate regulatory network influenced by a myriad of signaling molecules, transcription factors, epigenetic modifications, and metabolic reprogramming. In this review, our primary focus is on the classically activated macrophages (M1-like) and alternatively activated macrophages (M2-like) as the two paramount phenotypes instrumental in sepsis' host immune response. An imbalance between M1-like and M2-like macrophages can precipitate the onset and exacerbate the progression of sepsis. This review provides a comprehensive understanding of the interplay between macrophage polarization and sepsis-induced acute lung injury (SALI) and elaborates on the intervention strategy that centers around the crucial process of macrophage polarization.

Cellular heterogeneity and plasticity during NAFLD progression

Nonalcoholic fatty liver disease (NAFLD) is a progressive liver disease that can progress to nonalcoholic steatohepatitis (NASH), NASH-related cirrhosis, and hepatocellular carcinoma (HCC). NAFLD ranges from simple steatosis (or nonalcoholic fatty liver [NAFL]) to NASH as a progressive form of NAFL, which is characterized by steatosis, lobular inflammation, and hepatocellular ballooning with or without fibrosis. Because of the complex pathophysiological mechanism and the heterogeneity of NAFLD, including its wide spectrum of clinical and histological characteristics, no specific therapeutic drugs have been approved for NAFLD. The heterogeneity of NAFLD is closely associated with cellular plasticity, which describes the ability of cells to acquire new identities or change their phenotypes in response to environmental stimuli. The liver consists of parenchymal cells including hepatocytes and cholangiocytes and nonparenchymal cells including Kupffer cells, hepatic stellate cells, and endothelial cells, all of which have specialized functions. This heterogeneous cell population has cellular plasticity to adapt to environmental changes. During NAFLD progression, these cells can exert diverse and complex responses at multiple levels following exposure to a variety of stimuli, including fatty acids, inflammation, and oxidative stress. Therefore, this review provides insights into NAFLD heterogeneity by addressing the cellular plasticity and metabolic adaptation of hepatocytes, cholangiocytes, hepatic stellate cells, and Kupffer cells during NAFLD progression.

Regulatory role of exosomes in colorectal cancer progression and potential as biomarkers

Colorectal cancer (CRC) remains an enormous challenge to human health worldwide. Unfortunately, the mechanism underlying CRC progression is not well understood. Mounting evidence has confirmed that exosomes play a vital role in CRC progression, which has attracted extensive attention among researchers. In addition to acting as messengers between CRC cells, exosomes also participate in the CRC immunomodulatory process and reshape immune function. As stable message carriers and liquid biopsy option under development, exosomes are promising biomarkers in the diagnosis or treatment of CRC. In this review we have described and analyzed the biogenesis and release of exosomes and current research on the role of exosomes in immune regulation and metastasis of CRC. Moreover, we have discussed candidate exosomal molecules as potential biomarkers to diagnose CRC, predict CRC progression, or determine CRC chemoresistance, and described the significance of exosomes in the immunotherapy of CRC. This review provides insight to further understand the role of exosomes in CRC progression and identify valuable biomarkers that facilitate the clinical management of CRC patients.

Macrophages as Promising Carriers for Nanoparticle Delivery in Anticancer Therapy

Macrophages play a critical role in the immune response due to their ability to recognize and remove pathogens, as well as present antigens, which are involved in inflammation, but they are also one of the most abundant immune cell populations present in the tumor microenvironment. In recent years, macrophages have become promising cellular carriers for drug and nanoparticle delivery to the tumor microenvironment, mainly due to their natural properties such as biocompatibility, degradability, lack of immunogenicity, long half-life in circulation, crossing biological barriers, and the possibility of migration and accumulation at a site of inflammation such as a tumor. For the effectiveness of this therapeutic strategy, known as "Trojan horse", it is important that the nanoparticles engulfed by macrophages do not affect their proper functioning. In our review, we discussed how the size, shape, chemical and mechanical properties of nanoparticles influence their internalization by macrophages. In addition, we described the promising research utilizing macrophages, their cell membranes and macrophage-derived exosomes as drug carriers in anticancer therapy. As a prospect of the wider use of this therapeutic strategy, we postulate its future application in boron delivery to the tumor environment in boron neutron capture therapy.

Biomimetic Nanoparticles Loaded with Ulinastatin for the Targeted Treatment of Acute Pancreatitis

Ulinastatin is commonly used in the clinic to treat acute pancreatitis (AP), but its therapeutic effect was limited by the presence of the blood-pancreas barrier (BPB) and low specificity. Here, we prepared a macrophage biomimetic nanoparticle (MU) that delivered ulinastatin to address the above issues. Macrophage membrane was used as a shell for a mixture of PEG-PLGA and ulinastatin. It was found that MU showed good stability and biocompatibility in vitro and in vivo. According to in vivo fluorescence imaging, MU displayed a great inflammation targeting effect both in a subcutaneous inflammation model and in situ pancreatitis mouse model, which was ascribed to the presence of adhesion proteins. In vitro and in vivo results demonstrated that MU have a superior AP treatment effect by inhibiting pro-inflammatory factors and keeping cells viability. It was suggested the MU could provide a new strategy for targeted AP treatment.

Molecular and cellular mechanisms of inflammation in atherosclerosis

Atherosclerosis and its complications are a major cause of morbidity and mortality worldwide in spite of the improved medical and invasive treatment in terms of revascularization. Atherosclerosis is a dynamic, multi-step process in which inflammation is a ubiquitous component participating in the initiation, development, and entanglements of the atherosclerotic plaque. After activation, the immune system, either native or acquired, is part of the atherosclerotic dynamics enhancing the pro-atherogenic function of immune or non-immune cells, such as endothelial cells, smooth muscle cells, or platelets, through mediators such as cytokines or directly by cell-to-cell interaction. Cytokines are molecules secreted by the activated cells mentioned above that mediate the inflammatory component of atherosclerosis whose function is to stimulate the immune cells and the production of further cytokines. This review provides insights of the cell axis activation and specific mechanisms and pathways through which inflammation actuates atherosclerosis.

Soybean (Glycine max) INFOGEST Colonic Digests Attenuated Inflammatory Responses Based on Protein Profiles of Different Varieties

Soybean compounds have been established to modulate inflammation, but less is known about how whole soybean compositions work together after digestion. The objective was to evaluate and compare the anti-inflammatory responses of different soybean varieties under simulated gastrointestinal digestion, with additional consideration of the glycinin:β-conglycinin ratio (GBR). Soybean colonic digests (SCD) inhibited cyclooxygenase (COX)-2 (25-82%), 5-lipoxidase (LOX) (18-35%), and inducible nitric oxide (iNOS) (8-61%). Varieties 88, GN3, and 93 were the most effective inhibitors. SCD (1 mg/mL) of varieties 81 and GN1 significantly (p < 0.05) reduced nitrite production by 44 and 47%, respectively, compared to lipopolysaccharide (LPS)-stimulated macrophages. SCD effectively reduced pro-inflammatory cytokine interleukin (IL)-6 (50 and 80% for 96 and GN1, respectively). Western blot results showed a decrease in the expression of iNOS, p65, and p50. The GBR was in the range of 0.05-1.57. Higher ratio correlated with higher production of IL-1β (r = 0.44) and tumor necrosis factor-alpha (TNF-α, r = 0.56). Inflammatory microarray results showed a significant decrease in expression of markers granulocyte-macrophage colony-stimulating factor (GM-CSF) and IL-6 in cells treated with GN1 SCD compared to LPS. The results suggested that SCD exerted its anti-inflammatory potential through nuclear factor kappa B (NF-κΒ) pathway inhibition by decreasing the levels of NF-κB-dependent cytokines and subunits, and inhibition of pro-inflammatory enzyme activity.

The role of long non-coding RNAs in breast cancer microenvironment

The tumor microenvironment (TME), which includes tumor cells, fibroblasts, endothelial cells, immune cells, and blood vessels, can affect tumor growth and metastasis. Studies have shown that tumor cells, fibroblasts, and macrophages can promote the development of tumors, while T and B cells can inhibit tumor progression. The crosstalk among different cells within the TME needs further study. Long non-coding RNAs (lncRNAs) are involved in biological processes, including cell proliferation, migration, and differentiation. The abnormal expression of certain lncRNAs is correlated with the progression of breast cancer and has been proven as diagnostic markers in various cancers, including breast cancer. In breast cancer, recent studies have shown that tumor cell- and non-tumor cell-derived lncRNAs can affect various facets of tumor progression, including growth, proliferation, and migration of tumor cells. Interestingly, in addition to being regulated by lncRNAs derived from tumor and non-tumor cells, the TME can regulate the expression of lncRNAs in tumor cells, fibroblasts, and macrophages, influencing their phenotype and function. However, the detailed molecular mechanisms of these phenomena remain unclear in the breast cancer microenvironment. Currently, many studies have shown that TME-associated lncRNAs are potential diagnostic and therapeutic targets for breast cancer. Considering that TME and lncRNAs can regulate each other, we summarize the role of lncRNAs in the breast cancer microenvironment and the potential of lncRNAs as valuable diagnostic markers.

Erythroid-transdifferentiated myeloid cells promote portal vein tumor thrombus in hepatocellular carcinoma

Rationale: Hepatocellular carcinoma (HCC) is primarily characterized by a high incidence of vascular invasion. However, the specific mechanism underlying portal vein tumor thrombus (PVTT) in HCC remains unclear. As a consequence of myeloid cell developmental arrest, CD71+ erythroid progenitor cells (EPCs) and myeloid-derived suppressor cells play important roles in HCC; however, their roles in PVTT remain unclear. Methods: The role of CD71+ EPCs in the HCC tumor microenvironment (TME) was evaluated via morphological, RNA-sequencing, enzyme-linked immunosorbent assay, and flow cytometric analyses. Co-culture techniques were employed to assess the CD45+ EPCs and their vascular compromising effect. Additionally, the PVTT-promoting function of CD45+ EPCs was explored in vivo in a murine model. Results: The CD45+EPCs in HCC tissues exhibited increased myeloid cell features, including morphology, surface markers, transforming growth factor (TGF)-β generation, and gene expression, compared with those in circulation. Hence, a large proportion of CD45+EPCs, particularly those in TMEs, comprise erythroid-transdifferentiated myeloid cells (EDMCs). Additionally, the expression of C-C chemokine receptor type 2 (CCR2) mRNA was upregulated in CD45+EPCs within the TME. Tumor macrophages from HCC tissues induced substantial migration of CD45+EPCs in a dose-dependent manner. Meanwhile, results from immunofluorescence analyses revealed that these two cell types are positively associated in the TME and circulation. That is, EDMCs are chemoattracted by HCC macrophages mainly via CCR2 from CD45+ EPCs in the circulation. Additionally, the expressions of FX, FVII, FGB, C4b, CFB, and CFH were elevated in CD45+EPCs within the TME compared with those in the spleen. The CD45+EPCs from the HCC TME promoted vessel endothelial cell migration and compromised tube formation through TGF-β and FGB, respectively. Additionally, CD45+EPCs from the TME induced HCC cell migration. HCC macrophage-induced CD45+EPCs to exhibit higher levels of FX, FVII, FGB, and TGF-β. Meanwhile, upregulation of CCAAT/enhancer binding protein beta expression induced FGB and TGF-β generation in CD45+EPCs in the TME. WTAP, a major RNA m6A writer, stabilized FX and FVII mRNA and enhanced their nuclear export in CD45+EPCs from the TME. CD45+EPCs from the TME were positively associated with PVTT and poor prognosis. Splenectomy reduced the level of CD45+EPCs in the circulation and TME, as well as the incidence of microvascular invasion. The incidence of microvascular invasion increased following the transfer of HCC tissue CD45+EPCs to splenectomized HCC-bearing mice. Conclusions: The CD45+EPCs enriched in the HCC microenvironment are EDMCs, which are induced by HCC macrophages to migrate from the circulation to the TME. Subsequently, EDMCs promote PVTT by compromising the blood vessel endothelium, aggravating coagulation, and promoting HCC cell migration.

How do parasitic worms prevent diabetes? An exploration of their influence on macrophage and β-cell crosstalk

Diabetes is the fastest growing chronic disease globally, with prevalence increasing at a faster rate than heart disease and cancer. While the disease presents clinically as chronic hyperglycaemia, two distinct subtypes have been recognised. Type 1 diabetes (T1D) is characterised as an autoimmune disease in which the insulin-producing pancreatic β-cells are destroyed, and type 2 diabetes (T2D) arises due to metabolic insufficiency, in which inadequate amounts of insulin are produced, and/or the actions of insulin are diminished. It is now apparent that pro-inflammatory responses cause a loss of functional β-cell mass, and this is the common underlying mechanism of both T1D and T2D. Macrophages are the central immune cells in the pathogenesis of both diseases and play a major role in the initiation and perpetuation of the proinflammatory responses that compromise β-cell function. Furthermore, it is the crosstalk between macrophages and β-cells that orchestrates the inflammatory response and ensuing β-cell dysfunction/destruction. Conversely, this crosstalk can induce immune tolerance and preservation of β-cell mass and function. Thus, specifically targeting the intercellular communication between macrophages and β-cells offers a unique strategy to prevent/halt the islet inflammatory events underpinning T1D and T2D. Due to their potent ability to regulate mammalian immune responses, parasitic worms (helminths), and their excretory/secretory products, have been examined for their potential as therapeutic agents for both T1D and T2D. This research has yielded positive results in disease prevention, both clinically and in animal models. However, the focus of research has been on the modulation of immune cells and their effectors. This approach has ignored the direct effects of helminths and their products on β-cells, and the modulation of signal exchange between macrophages and β-cells. This review explores how the alterations to macrophages induced by helminths, and their products, influence the crosstalk with β-cells to promote their function and survival. In addition, the evidence that parasite-derived products interact directly with endocrine cells to influence their communication with macrophages to prevent β-cell death and enhance function is discussed. This new paradigm of two-way metabolic conversations between endocrine cells and macrophages opens new avenues for the treatment of immune-mediated metabolic disease.

Tumor-Associated Macrophages Affect the Tumor Microenvironment and Radioresistance via the Upregulation of CXCL6/CXCR2 in Hepatocellular Carcinoma

BACKGROUND

Hepatocellular carcinoma is the sixth most diagnosed malignancy and the fourth most common cause of cancer-related mortality globally. Despite progress in the treatment of liver cancer, nonsurgical treatments remain unsatisfactory, and only 15% of early-stage cases are surgically operable. Radiotherapy (RT) is a non-surgical treatment option for liver cancer when other traditional treatment methods are ineffective. However, RT has certain limitations, including eliciting poor therapeutic effects in patients with advanced and recurrent tumors. Tumor-associated macrophages (TAMs) are major inflammatory cells in the tumor microenvironment that are key to tumor development, angiogenesis, invasion, and metastasis, and they play an essential role in RT responses.

METHODS

We used big data analysis to determine the potential of targeting CXCL6/CXCR2. We enrolled 50 patients with liver cancer who received RT at our hospital. Tumor tissue samples were examined for any relationship between CXCL6/CXCR2 activity and patient prognosis. Using a cell coculture system (Transwell), we cocultured Huh7 liver cancer cells and THP-1 monocytes with and without CXCL6/CXCR2 small interfering RNA for 72 h.

RESULTS

The overexpression of CXCL6/CXCR2 was highly correlated with mortality. Our tissue study indicated a positive correlation between CXCL6/CXCR2 and M2-TAMs subsets. The coculture study demonstrated that THP-1 monocytes can secrete CXCL6, which acts on the CXCR2 receptor on the surface of Huh7 cells and activates IFN-g/p38 MAPK/NF-κB signals to promote the epithelial-mesenchymal transition and radio-resistance.

CONCLUSIONS

Modulating the TAM/CXCL6/CXCR2 tumor immune signaling axis may be a new treatment strategy for the effective eradication of radiotherapy-resistant hepatocellular carcinoma cells.

Research progress into adipose tissue macrophages and insulin resistance

In recent years, there has been an increasing incidence of metabolic syndrome, type 2 diabetes, and cardiovascular events related to insulin resistance. As one of the target organs for insulin, adipose tissue is essential for maintaining in vivo immune homeostasis and metabolic regulation. Currently, the specific adipose tissue mechanisms involved in insulin resistance remain incompletely understood. There is increasing evidence that the process of insulin resistance is mostly accompanied by a dramatic increase in the number and phenotypic changes of adipose tissue macrophages (ATMs). In this review, we discuss the origins and functions of ATMs, some regulatory factors of ATM phenotypes, and the mechanisms through which ATMs mediate insulin resistance. We explore how ATM phenotypes contribute to insulin resistance in adipose tissue. We expect that modulation of ATM phenotypes will provide a novel strategy for the treatment of diseases associated with insulin resistance.

Integrating the characteristic genes of macrophage pseudotime analysis in single-cell RNA-seq to construct a prediction model of atherosclerosis

BACKGROUND

Macrophages play an important role in the occurrence and development of atherosclerosis. However, few existing studies have deliberately analyzed the changes in characteristic genes in the process of macrophage phenotype transformation.

METHOD

Carotid atherosclerotic plaque single-cell RNA (scRNA) sequencing data were analyzed to define the cells involved and determine their transcriptomic characteristics. KEGG enrichment analysis, CIBERSORT, ESTIMATE, support vector machine (SVM), random forest (RF), and weighted correlation network analysis (WGCNA) were applied to bulk sequencing data. All data were downloaded from Gene Expression Omnibus (GEO).

RESULT

Nine cell clusters were identified. M1 macrophages, M2 macrophages, and M2/M1 macrophages were identified as three clusters within the macrophages. According to pseudotime analysis, M2/M1 macrophages and M2 macrophages can be transformed into M1 macrophages. The ROC curve values of the six genes in the test group were statistically significant (AUC (IL1RN): 0.899, 95% CI: 0.764-0.990; AUC (NRP1): 0.817, 95% CI: 0.620-0.971; AUC (TAGLN): 0.846, 95% CI: 0.678-0.971; AUC (SPARCL1): 0.825, 95% CI: 0.620-0.988; AUC (EMP2): 0.808, 95% CI: 0.630-0.947; AUC (ACTA2): 0.784, 95% CI: 0.591-0.938). The atherosclerosis prediction model showed significant statistical significance in both the train group (AUC: 0.909, 95% CI: 0.842-0.967) and the test group (AUC: 0.812, 95% CI: 0.630-0.966).

CONCLUSIONS

IL1RNHigh M1, NRP1High M2, ACTA2High M2/M1, EMP2High M1/M1, SPACL1High M2/M1 and TAGLNHigh M2/M1 macrophages play key roles in the occurrence and development of arterial atherosclerosis. These marker genes of macrophage phenotypic transformation can also be used to establish a model to predict the occurrence of atherosclerosis.

Characterization of Chemotaxis-Associated Gene Dysregulation in Myeloid Cell Populations in the Lungs during Lipopolysaccharide-Mediated Acute Lung Injury

During endotoxin-induced acute lung injury (ALI), immune cell recruitment resulting from chemotaxis is mediated by CXC and CC chemokines and their receptors. In this study, we investigated the role of chemokines and their receptors in the regulation of myeloid cell populations in the circulation and the lungs of C57BL/6J mice exhibiting LPS-mediated ALI using single-cell RNA sequencing. During ALI, there was an increase in the myeloid cells, M1 macrophages, monocytes, neutrophils, and other granulocytes, whereas there was a decrease in the residential alveolar macrophages and M2 macrophages. Interestingly, LPS triggered the upregulation of CCL3, CCL4, CXCL2/3, and CXCL10 genes associated with cellular migration of various subsets of macrophages, neutrophils, and granulocytes. Furthermore, there was an increase in the frequency of myeloid cells expressing CCR1, CCR3, CCR5, and CXCR2 receptors during ALI. MicroRNA sequencing studies of vehicle versus LPS groups identified several dysregulated microRNAs targeting the upregulated chemokine genes. This study suggests that chemokine ligand-receptors interactions are responsible for myeloid cell heterogenicity and cellular recruitment to the lungs during ALI. The single-cell transcriptomics allowed for an in-depth assessment and characterization of myeloid cells involved in immune cell trafficking during ALI.

Regulatory Mechanism of M1/M2 Macrophage Polarization in the Development of Autoimmune Diseases

Macrophages are innate immune cells in the organism and can be found in almost tissues and organs. They are highly plastic and heterogeneous cells and can participate in the immune response, thereby playing a crucial role in maintaining the immune homeostasis of the body. It is well known that undifferentiated macrophages can polarize into classically activated macrophages (M1 macrophages) and alternatively activated macrophages (M2 macrophages) under different microenvironmental conditions. The directions of macrophage polarization can be regulated by a series of factors, including interferon, lipopolysaccharide, interleukin, and noncoding RNAs. To elucidate the role of macrophages in various autoimmune diseases, we searched the literature on macrophages with the PubMed database. Search terms are as follows: macrophages, polarization, signaling pathways, noncoding RNA, inflammation, autoimmune diseases, systemic lupus erythematosus, rheumatoid arthritis, lupus nephritis, Sjogren's syndrome, Guillain-Barré syndrome, and multiple sclerosis. In the present study, we summarize the role of macrophage polarization in common autoimmune diseases. In addition, we also summarize the features and recent advances with a particular focus on the immunotherapeutic potential of macrophage polarization in autoimmune diseases and the potentially effective therapeutic targets.

CD204⁺ tumor-associated macrophages are associated with clinical outcome in canine pulmonary adenocarcinoma and transitional cell carcinoma

Tumor-associated macrophages are abundant infiltrating cells in the tumor microenvironment (TME). Macrophages can be classified into several types of subsets based on their immune responses. Among those subsets, M2 macrophages contribute to anti-inflammatory responses and create an immunosuppressive environment that promotes tumor cell proliferation. In a previous study, human cancer patients with high M2 macrophages showed a worse prognosis for many types of tumors. However, studies examining the relationship between M2 macrophages and clinical outcomes in canine tumors are limited. In the previous human and canine studies, CD204 has been used as the marker for detecting M2 macrophages. Then we evaluated CD204+ and total macrophages infiltration and its association with clinical outcomes in canine solid tumors. In this study, we examined dogs with oral malignant melanoma (OMM), pulmonary adenocarcinoma (PA), hepatocellular carcinoma (HCC), and transitional cell carcinoma (TCC). Compared to healthy tissues, CD204+ and total macrophages were increased in OMM, PA, and TCC, but not in HCC. High CD204+ macrophage levels were significantly associated with lung metastasis in TCC (P = 0.030). Kaplan-Meier analysis revealed that high CD204+ macrophage levels were associated with shorter overall survival (OS) in canine patients with PA (P = 0.012) and TCC (P = 0.0053). These results suggest that CD204+ macrophages contribute to tumor progression and could be a prognostic factor in dogs with PA and TCC.

Transcriptome profiling explores the immune defence mechanism of triploid Pacific oyster (Crassostrea gigas) blood against Vibrio alginolyticus based on protein interaction networks

Triploid oysters have provided the oyster industry with many benefits, such as fast growth rates, meat quality improvement, and increased oyster production and economic benefits, since the first report on triploid oysters was published. The development of polyploid technology has remarkably increased the output of triploid oysters to meet the increasing demand of consumers for Crassostrea gigas in the past decades. At present, research on triploid oyster has mainly focused on breeding and growth, but studies on the immunity of triploid oysters are limited. According to recent reports, Vibrio alginolyticus is a highly virulent strain that can cause disease and death in shellfish, shrimp, as well as serious economic losses. V. alginolyticus may be a reason why oysters die during summer. Therefore, using V. alginolyticus to explore the resistance and immune defense mechanisms of triploid oysters against pathogens presents practical significance. Transcriptome analysis of gene expression was performed in triploid C. gigas at 12 and 48 h after infection with V. alginolyticus, and the respective 2257 and 191 differentially expressed genes (DEGs) were identified. The results of GO and KEGG enrichment analyses showed that multiple significantly enriched GO terms and KEGG signaling pathways are associated with immunity. A protein-protein interaction network was constructed to investigate the interaction relationship of immune-related genes. Finally, we verified the expression situation of 16 key genes using quantitative RT-PCR. This study is the first to use the PPI network in exploring the immune defense mechanism of triploid C. gigas blood to fill the gap in the immune mechanism of triploid oysters and other mollusks, and provide valuable reference for future triploid farming and pathogen prevention and control.

Cellular crosstalk in atherosclerotic plaque microenvironment

Atherosclerosis is an underlying pathology of many vascular diseases as a result of cellular, structural and molecular dysfunctions within the sub-endothelial space. This review deals with the events involved in the formation, growth and remodeling of plaque, including the cell recruitment, cell polarization, and cell fat droplets. It also describes cross talking between endothelial cells, macrophages, and vascular smooth muscle cells, as well as the cellular pathways involved in plaque development in the plaque microenvironment. Finally, it describes the plaque structural components and the role of factors involved in the rupture and erosion of plaques in the vessel. Video Abstract.

Innate Pulmonary Phagocytes and Their Interactions with Pathogenic Cryptococcus Species

Cryptococcus neoformans is an opportunistic fungal pathogen that causes over 180,000 annual deaths in HIV/AIDS patients. Innate phagocytes in the lungs, such as dendritic cells (DCs) and macrophages, are the first cells to interact with the pathogen. Neutrophils, another innate phagocyte, are recruited to the lungs during cryptococcal infection. These innate cells are involved in early detection of C. neoformans, as well as the removal and clearance of cryptococcal infections. However, C. neoformans has developed ways to interfere with these processes, allowing for the evasion of the host's innate immune system. Additionally, the innate immune cells have the ability to aid in cryptococcal pathogenesis. This review discusses recent literature on the interactions of innate pulmonary phagocytes with C. neoformans.

Significant association of MCP1 rs1024611 and CCR2 rs1799864 polymorphisms with colorectal cancer and liver metastases susceptibility and aggressiveness: A case-control study

BACKGROUND

The MCP-1/CCR2 axis is one of the major chemokine signaling pathways that play a crucial role in the tumor microenvironment and has been involved in triggering various tumor progression mechanisms, such as increasing the immunosuppressive cells recruitment and promoting tumor cell proliferation and invasiveness.

AIM

The current study investigated the association of MCP1 (rs1024611) and CCR2 (rs1799864) genes variants with the risk as well as prognosis of colorectal cancer (CRC) and colorectal liver metastases (CRLM).

SUBJECTS AND METHODS

A retrospective cohort study involved 408 patients (284 CRC and 124 CRLM), and 284 healthy control was conducted. Genotyping of selected polymorphisms was performed by PCR-RFLP assays and confirmed by microchip and capillary electrophoresis.

RESULTS

The results highlighted a positive association between MCP1 rs1024611 (non-AA) and CCR2 rs1799864 (GA) genotypes with increased CRC and CRLM risk. Correlation between SNPs and clinicopathological characteristics revealed a positive association between MCP1 rs1024611 and CCR2 rs1799864 (dominant model) and CRC poor prognosis features. Kaplan-Meier survival analysis revealed a significant association between MCP1 rs1024611 non-AA carriers and decreased survival rate. Neoadjuvant treatment showed an improvement in CRC and CRLM survival rates among carriers of MCP1 and CCR2 wild-type genotype. FOLFIRI chemotherapy exhibits reduced survival rates for patients who carried mutated genotypes of MCP1 and CCR2 polymorphisms.

CONCLUSION

Considering our results, we suggest That both MCP1 and CCR2 polymorphisms may constitute independent factors for CRC and CRLM occurrence and can be helpful targets for an efficient therapeutic approach.

BushenHuoxue decoction suppresses M1 macrophage polarization and prevents LPS induced inflammatory bone loss by activating AMPK pathway

Abnormal bone metabolism and subsequence osteoporotic fractures are common complications of chronic inflammatory diseases. No effective treatment for these bone-related complications is available at present. The chronic inflammatory state in these diseases has been considered as a key factor of bone loss. Therefore, the combination of inflammation inhibition and bone loss suppression may be an important strategy for reducing bone damage associated with inflammatory diseases. Bushen Huoxue Decoction (BSHXD) is a traditional Chinese herbal compound that has demonstrated the ability to improve bone quality and increase bone density. However, the efficacy of BSHXD on inflammatory bone loss and its underlying mechanisms remain unclear. This study aimed to investigate whether BSHXD inhibits inflammatory bone loss in mice and its potential molecular mechanisms. In the present study, the effect of BSHXD on lipopolysaccharide (LPS)-induced M1 polarization of RAW264.7 macrophage and on local inflammatory bone loss model of mouse skull was determined. The results showed that after treating RAW264.7 cells with LPS for 24 h, the expression levels of IL-1β (39.42 ± 3.076 ng/L, p < 0.05), IL-6 (49.24 ± 1.766 mg/L, p < 0.05) and TNF-α (286.3 ± 27.12 ng/L, p < 0.05) were significantly increased. The addition of BSHXD decreased the expression levels of IL-1β, IL-6, and TNF-α to 31.55 ± 1.296 ng/L, 37.94 ± 0.8869 mg/L, and 196.4 ± 25.25 ng/L, respectively (p < 0.05). The results of immunofluorescence staining, Western blotting (WB) and flow cytometry indicated that the proportion of M1 macrophages in RAW264.7 cells treated with BSHXD for 24 h was significantly lower than that in the LPS group (13.36% ± 0.9829% VS 24.80% ± 4.619%, p < 0.05). The evidence from in-vitro experiments showed that the immunomodulatory ability of BSHXD may be associated with the activation of AMP-dependent protein kinase (AMPK) pathway in LPS-treated macrophages. In addition, the results of micro-CT, H&E staining, immunohistochemical staining and immunofluorescence staining of mouse skull further demonstrated that BSHXD treatment significantly alleviated LPS-induced local bone loss and inflammatory damage in mouse skull model. All results indicated that BSHXD significantly inhibited inflammatory factors release and M1 polarization of macrophage through AMPK signaling pathway. Therefore, BSHXD may be a promising drug for the treatment of inflammatory bone loss.

Responses of hepatic sinusoidal cells to liver ischemia–reperfusion injury

The liver displays a remarkable regenerative capacity in response to acute liver injury. In addition to the proliferation of hepatocytes during liver regeneration, non-parenchymal cells, including liver macrophages, liver sinusoidal endothelial cells (LSECs), and hepatic stellate cells (HSCs) play critical roles in liver repair and regeneration. Liver ischemia–reperfusion injury (IRI) is a major cause of increased liver damage during liver resection, transplantation, and trauma. Impaired liver repair increases postoperative morbidity and mortality of patients who underwent liver surgery. Successful liver repair and regeneration after liver IRI requires coordinated interplay and synergic actions between hepatic resident cells and recruited cell components. However, the underlying mechanisms of liver repair after liver IRI are not well understood. Recent technological advances have revealed the heterogeneity of each liver cell component in the steady state and diseased livers. In this review, we describe the progress in the biology of liver non-parenchymal cells obtained from novel technological advances. We address the functional role of each cell component in response to liver IRI and the interactions between diverse immune repertoires and non-hematopoietic cell populations during the course of liver repair after liver IRI. We also discuss how these findings can help in the design of novel therapeutic approaches. Growing insights into the cellular interactions during liver IRI would enhance the pathology of liver IRI understanding comprehensively and further develop the strategies for improvement of liver repair.

Ferulic acid alleviates sciatica by inhibiting neuroinflammation and promoting nerve repair via the TLR4/NF-κB pathway

INTRODUCTION

Sciatica causes intense pain. No satisfactory therapeutic drugs exist to treat sciatica. This study aimed to probe the potential mechanism of ferulic acid in sciatica treatment.

METHODS

Thirty-two SD rats were randomly divided into 4 groups: sham operation, chronic constriction injury (CCI), mecobalamin, and ferulic acid. We conducted RNA sequencing, behavioral tests, ELISA, PCR, western blotting, and immunofluorescence analysis. TAK-242 and JSH23 were administered to RSC96 and GMI-R1 cells to explore whether ferulic acid can inhibit apoptosis and alleviate inflammation.

RESULTS

RNA sequencing showed that TLR4/NF-κB pathway is involved in the mechanism of sciatica. CCI induced cold and mechanical hyperalgesia; destroyed the sciatic nerve structure; increased IL-1β, IL-6, TNF-α, IL-8, and TGF-β protein levels and IL-1β, IL-6, TNF-α, TGF-β, TLR4, and IBA-1 mRNA levels; and decreased IL-10 and INF-γ protein levels and IL-4 mRNA levels. Immunohistochemistry showed that IBA-1, CD32, IL-1β, iNOS, nNOS, COX2, and TLR4 expression was increased while S100β and Arg-1 decreased. CCI increased TLR4, IBA-1, IL-1β, iNOS, Myd88, p-NF-κB, and p-p38MAPK protein levels. Treatment with mecobalamin and ferulic acid reversed these trends. Lipopolysaccharide (LPS) induced RSC96 cell apoptosis by reducing Bcl-2 and Bcl-xl protein and mRNA levels and increasing Bax and Bad mRNA and IL-1β, TLR4, Myd88, p-NF-κB, and p-p38MAPK protein levels, while ferulic acid inhibited cell apoptosis by decreasing IL-1β, TLR4, Myd88, p-NF-κB, and p-p38MAPK levels and increasing Bcl-2 and Bcl-xl levels. In GMI-R1 cells, Ferulic acid attenuated LPS-induced M1 polarization by decreasing the M1 polarization markers IL-1β, IL-6, iNOS, and CD32 and increasing the M2 polarization markers CD206, IL-4, IL-10 and Arg-1. After LPS treatment, IL-1β, iNOS, TLR4, Myd88, p-p38MAPK, and p-NF-κB levels were obviously increased, and Arg-1 expression was reduced, while ferulic acid reversed these changes.

CONCLUSION

Ferulic acid can promote injured sciatic nerve repair by reducing neuronal cell apoptosis and inflammatory infiltration though the TLR4/NF-κB pathway.

Label-free macrophage phenotype classification using machine learning methods

Macrophages are heterogeneous innate immune cells that are functionally shaped by their surrounding microenvironment. Diverse macrophage populations have multifaceted differences related to their morphology, metabolism, expressed markers, and functions, where the identification of the different phenotypes is of an utmost importance in modelling immune response. While expressed markers are the most used signature to classify phenotypes, multiple reports indicate that macrophage morphology and autofluorescence are also valuable clues that can be used in the identification process. In this work, we investigated macrophage autofluorescence as a distinct feature for classifying six different macrophage phenotypes, namely: M0, M1, M2a, M2b, M2c, and M2d. The identification was based on extracted signals from multi-channel/multi-wavelength flow cytometer. To achieve the identification, we constructed a dataset containing 152,438 cell events each having a response vector of 45 optical signals fingerprint. Based on this dataset, we applied different supervised machine learning methods to detect phenotype specific fingerprint from the response vector, where the fully connected neural network architecture provided the highest classification accuracy of 75.8% for the six phenotypes compared simultaneously. Furthermore, by restricting the number of phenotypes in the experiment, the proposed framework produces higher classification accuracies, averaging 92.0%, 91.9%, 84.2%, and 80.4% for a pool of two, three, four, five phenotypes, respectively. These results indicate the potential of the intrinsic autofluorescence for classifying macrophage phenotypes, with the proposed method being quick, simple, and cost-effective way to accelerate the discovery of macrophage phenotypical diversity.

Comprehensive analyses of A 12-metabolism-associated gene signature and its connection with tumor metastases in clear cell renal cell carcinoma

BACKGROUND

The outcomes of patients with clear cell renal cell carcinoma (ccRCC) were dreadful due to lethal local recurrence and distant metastases. Accumulating evidence suggested that ccRCC was considered a metabolic disease and metabolism-associated genes (MAGs) exerted essential functions in tumor metastases. Thus, this study intends to seek whether the dysregulated metabolism promotes ccRCC metastases and explores underlying mechanisms.

METHOD

Weighted gene co-expression network analysis (WGCNA) was employed based on 2131 MAGs to select genes mostly associated with ccRCC metastases for subsequent univariate Cox regression. On this basis, least absolute shrinkage and selection operator (LASSO) regression and multivariate Cox regression were employed to create a prognostic signature based on the cancer genome atlas kidney renal clear cell carcinoma (TCGA-KIRC) cohort. The prognostic signature was confirmed using E-MTAB-1980 and GSE22541 cohorts. Kaplan-Meier, receiver operating characteristic (ROC) curve, and univariate and multivariate Cox regression were applied to detect the predictability and independence of the signature in ccRCC patients. Functional enrichment analyses, immune cell infiltration examinations, and somatic variant investigations were employed to detect the biological roles of the signature.

RESULT

A 12-gene-metabolism-associated prognostic signature, termed the MAPS by our team, was constructed. According to the MAPS, patients were divided into low- and high-risk subgroups and high-risk patients displayed inferior outcomes. The MAPS was validated as an independent and reliable biomarker in ccRCC patients for forecasting the prognosis and progression of ccRCC patients. Functionally, the MAPS was closely associated with metabolism dysregulation, tumor metastases, and immune responses in which the high-risk tumors were in an immunosuppressive status. Besides, high-risk patients benefited more from immunotherapy and held a higher tumor mutation burden (TMB) than low-risk patients.

CONCLUSION

The 12-gene MAPS with prominent biological roles could independently and reliably forecast the outcomes of ccRCC patients, and provide clues to uncover the latent mechanism in which dysregulated metabolism controlled ccRCC metastases.

Clearance of bacteria from lymph nodes in sheep immunized with Brucella suis S2 vaccine is associated with M1 macrophage activation

Ovine brucellosis is a global zoonotic disease of sheep caused by Brucella melitensis, which inflicts a significant burden on human and animal health. Brucella suis strain S2 (B. suis S2) is a smooth live attenuated vaccine for the prevention of ovine brucellosis in China. However, no previous studies have assessed the immunogenicity of B. suis S2 vaccine after oral immunization in sheep. Here, we attempted to evaluate the ovine immune response over the course of B. suis S2 immunization and to identify in vivo predictors for vaccine development. Body temperature, serum Brucella antibodies, serum cytokines (IL-12p70 and interferon [IFN]-γ), and bacterial load in the mandibular lymph nodes (LN), superficial cervical LN, superficial inguinal LN, and spleen were investigated to determine the safety and efficacy of the vaccine. The abnormal body temperature of sheep occurred within 8 days post-infection (dpi). Brucella suis S2 persisted for a short time (< 21 dpi) in the mandibular LN. The highest level of IL-12p70 was observed at 9 dpi, whereas serum IFN-γ levels peaked at 12 dpi. Transcriptome analysis and quantitative reverse transcription PCR were performed to determine gene expression profiles in the mandibular LN of sheep. Antigen processing and presentation pathway was the dominant pathway related to the dataset. Our studies suggest that the immune response in ovine LN resembled type 1 immunity with the secretion of IL-12p70 and IFN-γ after B.suis S2 immunization and the vaccine may eliminate Brucella via stimulation of M1 macrophages through the course of Th cells.

The Pathological Activation of Microglia Is Modulated by Sexually Dimorphic Pathways

Microglia are the primary immunocompetent cells of the central nervous system (CNS). Their ability to survey, assess and respond to perturbations in their local environment is critical in their role of maintaining CNS homeostasis in health and disease. Microglia also have the capability of functioning in a heterogeneous manner depending on the nature of their local cues, as they can become activated on a spectrum from pro-inflammatory neurotoxic responses to anti-inflammatory protective responses. This review seeks to define the developmental and environmental cues that support microglial polarization towards these phenotypes, as well as discuss sexually dimorphic factors that can influence this process. Further, we describe a variety of CNS disorders including autoimmune disease, infection, and cancer that demonstrate disparities in disease severity or diagnosis rates between males and females, and posit that microglial sexual dimorphism underlies these differences. Understanding the mechanism behind differential CNS disease outcomes between men and women is crucial in the development of more effective targeted therapies.

The emerging role of cell cycle protein p53 expression by tumor cells and M2-macrophage infiltration in urinary bladder cancer

PURPOSE

To investigate the association between p53 expression in tumor cells and intratumoral macrophage infiltration in muscle-invasive urinary bladder cancer (MIBC) in relation to clinical and pathological variables and outcomes after radical cystectomy.

METHODS

Tumor specimens of the primary tumor from patients treated with radical cystectomy for MIBC were immunostained with the M2-macrophage-specific marker CD163 and the cell cycle protein p53. The expression of these markers was analyzed in relation to patients´ and tumor characteristics and outcome.

RESULTS

Out of 100 patients with urinary bladder cancer (UBC) pathological stage T1-4 N0-3 M0, 77% were men. The patients had a median age of 69 years and 80% had nonorgan-confined tumors (pT3-4). Lymph node metastasis was found in 42 (42%) of all patients. P53-positive expressions were found in 63 (63%) patients. Strong macrophage infiltration in the tumor microenvironment was shown in 74 (74%) patients. Combinations of CD163/p53 status were as follows: CD163+/p53+, 50%; CD163+/p53-, 24%; CD163-/p53+, 13%; and CD163-/p53-, 13%. Patients with CD163+/P53+ had higher proportions of organ-confined tumors.

CONCLUSIONS

In the present series of patients with MIBC treated with cystectomy, we found that high CD163+ macrophage infiltration in the tumor micro-environment often was combined with p53+ cancer cells. This simultaneous expression of p53 by tumor cells and increased infiltration of M2-macrophages in the tumor microenvironment was associated with improved CSS, which might indicate a possible protective effect of M2 macrophages in p53+ tumors. Further investigations are needed to explore the biological relation between mutational burden and immune profile in MIBC.

Capturing the multifaceted function of adipose tissue macrophages

Adipose tissue macrophages (ATMs) bolster obesity-induced metabolic dysfunction and represent a targetable population to lessen obesity-associated health risks. However, ATMs also facilitate adipose tissue function through multiple actions, including adipocyte clearance, lipid scavenging and metabolism, extracellular remodeling, and supporting angiogenesis and adipogenesis. Thus, high-resolution methods are needed to capture macrophages' dynamic and multifaceted functions in adipose tissue. Herein, we review current knowledge on regulatory networks critical to macrophage plasticity and their multifaceted response in the complex adipose tissue microenvironment.

Plasma osteopontin relates to myocardial fibrosis and steatosis and to immune activation among women with HIV

OBJECTIVE

Women with HIV (WWH) have heightened heart failure risk. Plasma OPN (osteopontin) is a powerful predictor of heart failure outcomes in the general population. Limited data exist on relationships between plasma OPN and surrogates of HIV-associated heart failure risk.

DESIGN

Prospective, cross-sectional.

METHODS

We analyzed relationships between plasma OPN and cardiac structure/function (assessed using cardiovascular magnetic resonance imaging) and immune activation (biomarkers and flow cytometry) among 20 WWH and 14 women without HIV (WWOH).

RESULTS

Plasma OPN did not differ between groups. Among WWH, plasma OPN related directly to the markers of cardiac fibrosis, growth differentiation factor-15 (ρ = 0.51, P = 0.02) and soluble interleukin 1 receptor-like 1 (ρ = 0.45, P = 0.0459). Among WWH (but not among WWOH or the whole group), plasma OPN related directly to both myocardial fibrosis (ρ = 0.49, P = 0.03) and myocardial steatosis (ρ = 0.46, P = 0.0487). Among the whole group and WWH (and not among WWOH), plasma OPN related directly to the surface expression of C-X3-C motif chemokine receptor 1 (CX3CR1) on nonclassical (CD14-CD16+) monocytes (whole group: ρ = 0.36, P = 0.04; WWH: ρ = 0.46, P = 0.04). Further, among WWH and WWOH (and not among the whole group), plasma OPN related directly to the surface expression of CC motif chemokine receptor 2 (CCR2) on inflammatory (CD14+CD16+) monocytes (WWH: ρ = 0.54, P = 0.01; WWOH: ρ = 0.60, P = 0.03), and in WWH, this held even after controlling for HIV-specific parameters.

CONCLUSION

Among WWH, plasma OPN, a powerful predictor of heart failure outcomes, related to myocardial fibrosis and steatosis and the expression of CCR2 and CX3CR1 on select monocyte subpopulations. OPN may play a role in heart failure pathogenesis among WWH.

CLINICALTRIALSGOV REGISTRATION

NCT02874703.

An Update of G-Protein-Coupled Receptor Signaling and Its Deregulation in Gastric Carcinogenesis

G-protein-coupled receptors (GPCRs) belong to a cell surface receptor superfamily responding to a wide range of external signals. The binding of extracellular ligands to GPCRs activates a heterotrimeric G protein and triggers the production of numerous secondary messengers, which transduce the extracellular signals into cellular responses. GPCR signaling is crucial and imperative for maintaining normal tissue homeostasis. High-throughput sequencing analyses revealed the occurrence of the genetic aberrations of GPCRs and G proteins in multiple malignancies. The altered GPCRs/G proteins serve as valuable biomarkers for early diagnosis, prognostic prediction, and pharmacological targets. Furthermore, the dysregulation of GPCR signaling contributes to tumor initiation and development. In this review, we have summarized the research progress of GPCRs and highlighted their mechanisms in gastric cancer (GC). The aberrant activation of GPCRs promotes GC cell proliferation and metastasis, remodels the tumor microenvironment, and boosts immune escape. Through deep investigation, novel therapeutic strategies for targeting GPCR activation have been developed, and the final aim is to eliminate GPCR-driven gastric carcinogenesis.

Integrated transcriptome-proteome analyses of human stem cells reveal source-dependent differences in their regenerative signature

Mesenchymal stem cells (MSCs) are gaining increasing prominence as an effective regenerative cellular therapy. However, ensuring consistent and reliable effects across clinical populations has proved to be challenging. In part, this can be attributed to heterogeneity in the intrinsic molecular and regenerative signature of MSCs, which is dependent on their source of origin. The present work uses integrated omics-based profiling, at different functional levels, to compare the anti-inflammatory, immunomodulatory, and angiogenic properties between MSCs from neonatal (umbilical cord MSC [UC-MSC]) and adult (adipose tissue MSC [AD-MSC], and bone marrow MSC [BM-MSC]) sources. Using multi-parametric analyses, we identified that UC-MSCs promote a more robust host innate immune response; in contrast, adult-MSCs appear to facilitate remodeling of the extracellular matrix (ECM) with stronger activation of angiogenic cascades. These data should help facilitate the standardization of source-specific MSCs, such that their regenerative signatures can be confidently used to target specific disease processes.

Salivary macrophage activation-related chemokines and mitogen-activated kinase kinase (MAPKK)-degrading proteolytic activity in type 1 diabetes mellitus

BACKGROUND

This cross-sectional study aimed to evaluate salivary concentrations of macrophage activation-related chemokines and mitogen-activated kinase kinase (MAPKK)-degrading proteolytic activity in children and adolescents with and without type 1 diabetes mellitus (T1DM).

METHODS

A total of 122 children and adolescents (65 T1DM patients, 50.8% female, mean age:10.9 years; 57 systemically healthy controls, 36.8% female, mean age: 9.5 years) were included in the study. Salivary concentrations of interferon gamma inducible protein-10 (IP-10), monocyte chemoattractant protein (MCP)-1, MCP-2, MCP-3, MCP-4, macrophage-derived chemokine (MDC), macrophage migration inhibitory factor (MIF), monokine induced by interferon gamma (MIG), and macrophage inflammatory protein-1 alpha (MIP-1α) were quantified using a bead-based technique. MAPKK-degrading proteolytic activity was detected using fluorescent peptide substrates.

RESULTS

The T1DM group had higher plaque index (PI%, p = 0.032) and bleeding on probing (BOP%, p = 0.045) scores, and lower decayed, missing, filled teeth (dmft/DMFT, p = 0.002) index scores compared to the healthy controls. Compared to the controls, salivary MCP-1 (p = 0.007), MCP-3 (p < 0.001), MIG (p = 0.007), and MIP-1α (p = 0.033) concentrations were elevated whereas MCP-4 concentrations decreased (p < 0.001) in the T1DM group. After adjusting for age, PI%, BOP%, and dmft/DMFT scores, significant differences in salivary concentrations of MIG (p = 0.033) and MIP-1α (p = 0.017) were observed between the groups. Moreover, protease activities directed to the cleavage sites of MEK23-18 (p = 0.001), MKK6b7-22 (p = 0.007), MKK451-66 (p = 0.005), MKK7b37-52 (p = 0.034), and MKK7b69-84 (p = 0.009) were elevated in the T1DM group.

CONCLUSION

T1DM disrupts the salivary macrophage activation-related chemokine profile and dysregulates proteolytic MAPKK cleavage. These findings can be an outcome of the impaired systemic immune response in T1DM.

The markers to delineate different phenotypes of macrophages related to metabolic disorders

Macrophages have a wide variety of roles in physiological and pathological conditions, making them promising diagnostic and therapeutic targets in diseases, especially metabolic disorders, which have attracted considerable attention in recent years. Owing to their heterogeneity and polarization, the phenotypes and functions of macrophages related to metabolic disorders are diverse and complicated. In the past three decades, the rapid progress of macrophage research has benefited from the emergence of specific molecular markers to delineate different phenotypes of macrophages and elucidate their role in metabolic disorders. In this review, we analyze the functions and applications of commonly used and novel markers of macrophages related to metabolic disorders, facilitating the better use of these macrophage markers in metabolic disorder research.

Physiological fibrin hydrogel modulates immune cells and molecules and accelerates mouse skin wound healing

Introduction

Wound healing is a complex process to restore homeostasis after injury and insufficient skin wound healing is a considerable problem in medicine. Whereas many attempts of regenerative medicine have been made for wound healing with growth factors and cell therapies, simple pharmacological and immunological studies are lagging behind. We investigated how fibrin hydrogels modulate immune cells and molecules in skin wound healing in mice.

Methods

Physiological fibrin hydrogels (3.5 mg/mL fibrinogen) were generated, biophysically analyzed for stiffness and protein contents and were structurally studied by scanning electron microscopy. Physiological fibrin hydrogels were applied to full thickness skin wounds and, after 3 days, cells and molecules in wound tissues were analyzed. Leukocytes, endothelial cells, fibroblasts and keratinocytes were explored with the use of Flow Cytometry, whereas cytokines and matrix metalloproteinases were analyzed with the use of qPCR, ELISAs and zymography. Skin wound healing was analyzed microscopically at day 3, macroscopically followed daily during repair in mice and compared with commercially available fibrin sealant Tisseel.

Results

Exogenous fibrin at physiological concentrations decreased neutrophil and increased non-classical Ly6Clow monocyte and resolutive macrophage (CD206⁺ and CX3CR1⁺) populations, at day 3 after injury. Fibrin hydrogel reduced the expression of pro-inflammatory cytokines and increased IL-10 levels. In line with these findings, gelatinase B/MMP-9 was decreased, whereas gelatinase A/MMP-2 levels remained unaltered. Frequencies of dermal endothelial cells, fibroblasts and keratinocytes were increased and keratinocyte migration was enhanced by fibrin hydrogel. Importantly, physiological fibrin accelerated the healing of skin wounds in contrast to the highly concentrated fibrin sealant Tisseel, which delayed wound repair and possessed a higher fiber density.

Conclusion

Collectively, we show that adding a tailored fibrin hydrogel scaffold to a wound bed positively influences the healing process, modulating leukocyte populations and inflammatory responses towards a faster wound repair.

Macrophages in Tumor-Associated Adipose Microenvironment Accelerate Tumor Progression

Adipose-tissue macrophages (ATMs), a complex ensemble of diverse macrophage subtypes, are prevalent in the tumor-adipose microenvironment (TAME) and facilitate tumor growth. However, the mechanisms in which the tumor-adipocyte crosstalk may enable the properties and plasticity of macrophages remain unclear. The single-cell RNA-sequence profiling reveals that a subset of macrophages expressed CD163, CCL2, and CCL5 in TAME, exhibiting an immunosuppressive subtype. It is demonstrated that CD163⁺ macrophages aggregate to surround adipocytes in breast cancer tissues. The expressions of CCL2 and CCL5 are also elevated in TAME and enable the recruitment and polarize macrophages. Mechanically, the level of exosomal miRNA-155 increased in the coculture of tumor cells and adipocytes, and then it promoted the generation and release of CCL2 and CCL5 from adipocytes by targeting the SOCS6/STAT3 pathway. Inhibition of exosomal miRNA-155 in tumor cells reduced the CCL2 and CCL5 levels in tumor-adipocytes coculture and further retarded tumor growth. Finally, the deletion of macrophages partially inhibited adipocyte-induced tumor proliferation. Likewise, inhibiting chemokines and their receptors or suppressing the phosphorylation of STAT3 decreased tumor burden in preclinical models. These results demonstrate that the niche factors in TAME, such as exosomal miRNA-155, regulate the function and polarity of macrophages to facilitate tumor progression.

Advances in the role of STAT3 in macrophage polarization

The physiological processes of cell growth, proliferation, differentiation, and apoptosis are closely related to STAT3, and it has been demonstrated that aberrant STAT3 expression has an impact on the onset and progression of a number of inflammatory immunological disorders, fibrotic diseases, and malignancies. In order to produce the necessary biological effects, macrophages (M0) can be polarized into pro-inflammatory (M1) and anti-inflammatory (M2) types in response to various microenvironmental stimuli. STAT3 signaling is involved in macrophage polarization, and the research of the effect of STAT3 on macrophage polarization has gained attention in recent years. In order to provide references for the treatment and investigation of disorders related to macrophage polarization, this review compiles the pertinent signaling pathways associated with STAT3 and macrophage polarization from many fundamental studies.

Physiology of chemokines in the cancer microenvironment

Chemokines are chemotactic cytokines whose canonical functions govern movement of receptor-expressing cells along chemical gradients. Chemokines are a physiological system that is finely tuned by ligand and receptor expression, ligand or receptor oligomerization, redundancy, expression of atypical receptors, and non-GPCR binding partners that cumulatively influence discrete pharmacological signaling responses and cellular functions. In cancer, chemokines play paradoxical roles in both the directed emigration of metastatic, receptor-expressing cancer cells out of the tumor as well as immigration of tumor-infiltrating immune cells that culminate in a tumor-unique immune microenvironment. In the age of precision oncology, strategies to effectively harness the power of immunotherapy requires consideration of chemokine gradients within the unique spatial topography and temporal influences with heterogeneous tumors. In this article, we review current literature on the diversity of chemokine ligands and their cellular receptors that detect and process chemotactic gradients and illustrate how differences between ligand recognition and receptor activation influence the signaling machinery that drives cellular movement into and out of the tumor microenvironment. Facets of chemokine physiology across discrete cancer immune phenotypes are contrasted to existing chemokine-centered therapies in cancer.

C-Terminal Fibronectin Exerts Beneficial Effects in Reducing Tissue Damage and Modulating Macrophage Function in a Murine Septic Model

Background

Fibronectin (FN) can improve organ function and slow the progression of sepsis, but full-length FN is hard to be exacted as a therapeutic.

Objective

This study aimed to investigate the beneficial effects of C-terminal heparin-binding domain polypeptide of FN (rhFNHC-36) in a cecal ligation and puncture (CLP)-mediated murine septic model and explore its regulatory effects on macrophages.

Methods

Mice were randomly assigned to four groups: unoperated control (Normal), sham operation control (Sham), CLP-operation with intravenous injection of phosphate-buffered saline (CLP+PBS), and CLP-operation with rhFNHC-36 treatment (CLP+rhFNHC-36). Blood and abdominal fluid samples were subjected to bacterial colony formation assays. Organs (liver, spleen, and lung) were undergone histopathological analyses and/or weighed to obtain organ indices. Serum interleukin-6 (IL-6) levels, nitric oxide (NO) release from isolated abdominal macrophages, and chemotactic effect of macrophages were measured with commercial kits. Surface programmed death ligand 1 (PD-L1) expression on macrophages was measured by flow cytometry.

Results

Mice in the CLP+PBS group showed a lower survival rate than that in the CLP+rhFNHC-36 group. Improved survival was associated with better clearance of bacterial pathogens, as evidenced by colony formation assays. The CLP-induced decrease in thymus and spleen indices was attenuated by rhFNHC-36 treatments. rhFNHC-36 alleviated sepsis-associated tissue damage in liver, spleen, and lung. CLP-mediated increases in plasma IL-6 levels were reversed by rhFNHC-36 treatment. NO levels in peritoneal macrophages after lipopolysaccharides (LPS)-stimulation in the CLP+rhFNHC-36 group were lower than that in the CLP+PBS group. Notably, macrophages from the CLP+rhFNHC-36 group retained better chemotaxis ability. After LPS challenge, these macrophages had a reduced percentage of PD-L1-positive cells compared to those in the CLP+PBS group.

Conclusion

rhFNHC-36 improved survival of mice with CLP-induced sepsis by reducing tissue damage and modulating macrophage function. Our work provides critical insight for developing FN-based and macrophages-targeted therapeutics for treating sepsis.

Treating inflammation to combat non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) with its more progressive form non-alcoholic steatohepatitis (NASH) has become the most common chronic liver disease, thereby representing a great burden for patients and healthcare systems. Specific pharmacological therapies for NAFLD are still missing. Inflammation is an important driver in the pathogenesis of NASH, and the mechanisms underlying inflammation in NAFLD represent possible therapeutic targets. In NASH, various intra- and extrahepatic triggers involved in the metabolic injury typically lead to the activation of different immune cells. This includes hepatic Kupffer cells, i.e. liver-resident macrophages, which can adopt an inflammatory phenotype and activate other immune cells by releasing inflammatory cytokines. As inflammation progresses, Kupffer cells are increasingly replaced by monocyte-derived macrophages with a distinct lipid-associated and scar-associated phenotype. Many other immune cells, including neutrophils, T lymphocytes - such as auto-aggressive cytotoxic as well as regulatory T cells - and innate lymphoid cells balance the progression and regression of inflammation and subsequent fibrosis. The detailed understanding of inflammatory cell subsets and their activation pathways prompted preclinical and clinical exploration of potential targets in NAFLD/NASH. These approaches to target inflammation in NASH include inhibition of immune cell recruitment via chemokine receptors (e.g. cenicriviroc), neutralization of CD44 or galectin-3 as well as agonism to nuclear factors like peroxisome proliferator-activated receptors and farnesoid X receptor that interfere with the activation of immune cells. As some of these approaches did not demonstrate convincing efficacy as monotherapies, a rational and personalized combination of therapeutic interventions may be needed for the near future.

Bromelain Ameliorates Atherosclerosis by Activating the TFEB-Mediated Autophagy and Antioxidant Pathways

Bromelain, a cysteine protease found in pineapple, has beneficial effects in the treatment of inflammatory diseases; however, its effects in cardiovascular pathophysiology are not fully understood. We investigated the effect of bromelain on atherosclerosis and its regulatory mechanisms in hyperlipidemia and atheroprone apolipoprotein E-null (apoe-/-) mice. Bromelain was orally administered to 16-week-old male apoe-/- mice for four weeks. Daily bromelain administration decreased hyperlipidemia and aortic inflammation, leading to atherosclerosis retardation in apoe-/- mice. Moreover, hepatic lipid accumulation was decreased by the promotion of cholesteryl ester hydrolysis and autophagy through the AMP-activated protein kinase (AMPK)/transcription factor EB (TFEB)-mediated upregulation of autophagy- and antioxidant-related proteins. Moreover, bromelain decreased oxidative stress by increasing the antioxidant capacity and protein expression of antioxidant proteins while downregulating the protein expression of NADPH oxidases and decreasing the production of reactive oxygen species. Therefore, AMPK/TFEB signaling may be crucial in bromelain-mediated anti-hyperlipidemia, antioxidant, and anti-inflammatory effects, effecting the amelioration of atherosclerosis.

Immunotherapy strategies and prospects for acute lung injury: Focus on immune cells and cytokines

Acute lung injury/acute respiratory distress syndrome (ALI/ARDS) is a disastrous condition, which can be caused by a wide range of diseases, such as pneumonia, sepsis, traumas, and the most recent, COVID-19. Even though we have gained an improved understanding of acute lung injury/acute respiratory distress syndrome pathogenesis and treatment mechanism, there is still no effective treatment for acute lung injury/acute respiratory distress syndrome, which is partly responsible for the unacceptable mortality rate. In the pathogenesis of acute lung injury, the inflammatory storm is the main pathological feature. More and more evidences show that immune cells and cytokines secreted by immune cells play an irreplaceable role in the pathogenesis of acute lung injury. Therefore, here we mainly reviewed the role of various immune cells in acute lung injury from the perspective of immunotherapy, and elaborated the crosstalk of immune cells and cytokines, aiming to provide novel ideas and targets for the treatment of acute lung injury.

Whole transcriptome expression profiles in kidney samples from rats with hyperuricaemic nephropathy

Hyperuricaemic nephropathy (HN) is a common clinical complication of hyperuricaemia (HUA) and poses a huge threat to human health. Hence, we aimed to prospectively investigate the dysregulated genes, pathways and networks involved in HN by performing whole transcriptome sequencing using RNA sequencing. Six kidney samples from HN group (n = 3) and a control group (n = 3) were obtained to conduct RNA sequencing. To disclose the relevant signalling pathways, we conducted the analysis of differentially expressed genes (DEGs), Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. A competitive endogenous RNA (ceRNA) network was established to reveal the interactions between lncRNAs, circRNAs, mRNAs and miRNAs and investigate the potential mechanisms of HN. Ultimately, 2250 mRNAs, 306 lncRNAs, 5 circRNAs, and 70 miRNAs were determined to be significantly differentially expressed in the HN group relative to the control group. We further authenticated 8 differentially expressed (DE)-ncRNAs by quantitative real-time polymerase chain reaction, and these findings were in accordance with the sequencing results. The analysis results evidently showed that these DE-ncRNAs were significantly enriched in pathways related to inflammatory reaction. In conclusion, HUA may generate abnormal gene expression changes and regulate signalling pathways in kidney samples. Potentially related genes and pathways involved in HN were identified.

Macrophage-Orbital Fibroblast Interaction and Hypoxia Promote Inflammation and Adipogenesis in Graves' Orbitopathy

The inflammatory eye disease Graves' orbitopathy (GO) is the main complication of autoimmune Graves' disease. In previous studies we have shown that hypoxia plays an important role for progression of GO. Hypoxia can maintain inflammation by attracting inflammatory cells such as macrophages (MQ). Herein, we investigated the interaction of MQ and orbital fibroblasts (OF) in context of inflammation and hypoxia. We detected elevated levels of the hypoxia marker HIF-1α, the MQ marker CD68, and inflammatory cytokines TNFα, CCL2, CCL5, and CCL20 in GO biopsies. Hypoxia stimulated GO tissues to release TNFα, CCL2, and CCL20 as measured by multiplex enzyme-linked immunosorbent assay (ELISA). Further, TNFα and hypoxia stimulated the expression of HIF-1α, CCL2, CCL5, and CCL20 in OF derived from GO tissues. Immunofluorescence confirmed that TNFα-positive MQ were present in the GO tissues. Thus, interaction of M1-MQ with OF under hypoxia also induced HIF-1α, CCL2, and CCL20 in OF. Inflammatory inhibitors etanercept or dexamethasone prevented the induction of HIF-1α and release of CCL2 and CCL20. Moreover, co-culture of M1-MQ/OF under hypoxia enhanced adipogenic differentiation and adiponectin secretion. Dexamethasone and HIF-1α inhibitor PX-478 reduced this effect. Our findings indicate that GO fat tissues are characterized by an inflammatory and hypoxic milieu where TNFα-positive MQ are present. Hypoxia and interaction of M1-MQ with OF led to enhanced secretion of chemokines, elevated hypoxic signaling, and adipogenesis. In consequence, M1-MQ/OF interaction results in constant inflammation and tissue remodeling. A combination of anti-inflammatory treatment and HIF-1α reduction could be an effective treatment option.