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

BHLHE40 Regulates Myeloid Cell Polarization through IL-10-Dependent and -Independent Mechanisms

Better understanding of the host responses to Mycobacterium tuberculosis infections is required to prevent tuberculosis and develop new therapeutic interventions. The host transcription factor BHLHE40 is essential for controlling M. tuberculosis infection, in part by repressing Il10 expression, where excess IL-10 contributes to the early susceptibility of Bhlhe40-/- mice to M. tuberculosis infection. Deletion of Bhlhe40 in lung macrophages and dendritic cells is sufficient to increase the susceptibility of mice to M. tuberculosis infection, but how BHLHE40 impacts macrophage and dendritic cell responses to M. tuberculosis is unknown. In this study, we report that BHLHE40 is required in myeloid cells exposed to GM-CSF, an abundant cytokine in the lung, to promote the expression of genes associated with a proinflammatory state and better control of M. tuberculosis infection. Loss of Bhlhe40 expression in murine bone marrow-derived myeloid cells cultured in the presence of GM-CSF results in lower levels of proinflammatory associated signaling molecules IL-1β, IL-6, IL-12, TNF-α, inducible NO synthase, IL-2, KC, and RANTES, as well as higher levels of the anti-inflammatory-associated molecules MCP-1 and IL-10 following exposure to heat-killed M. tuberculosis. Deletion of Il10 in Bhlhe40-/- myeloid cells restored some, but not all, proinflammatory signals, demonstrating that BHLHE40 promotes proinflammatory responses via both IL-10-dependent and -independent mechanisms. In addition, we show that macrophages and neutrophils within the lungs of M. tuberculosis-infected Bhlhe40-/- mice exhibit defects in inducible NO synthase production compared with infected wild-type mice, supporting that BHLHE40 promotes proinflammatory responses in innate immune cells, which may contribute to the essential role for BHLHE40 during M. tuberculosis infection in vivo.

Fenofibrate Induces a Resolving Profile in Heart Macrophage Subsets and Attenuates Acute Chagas Myocarditis

Chagas disease, caused by Trypanosoma cruzi, stands as the primary cause of dilated cardiomyopathy in the Americas. Macrophages play a crucial role in the heart's response to infection. Given their functional and phenotypic adaptability, manipulating specific macrophage subsets could be vital in aiding essential cardiovascular functions including tissue repair and defense against infection. PPARα are ligand-dependent transcription factors involved in lipid metabolism and inflammation regulation. However, the role of fenofibrate, a PPARα ligand, in the activation profile of cardiac macrophages as well as its effect on the early inflammatory and fibrotic response in the heart remains unexplored. The present study demonstrates that fenofibrate significantly reduces not only the serum activity of tissue damage biomarker enzymes (LDH and GOT) but also the circulating proportions of pro-inflammatory monocytes (CD11b+ LY6Chigh). Furthermore, both CD11b+ Ly6Clow F4/80high macrophages (MΦ) and recently differentiated CD11b+ Ly6Chigh F4/80high monocyte-derived macrophages (MdMΦ) shift toward a resolving phenotype (CD206high) in the hearts of fenofibrate-treated mice. This shift correlates with a reduction in fibrosis, inflammation, and restoration of ventricular function in the early stages of Chagas disease. These findings encourage the repositioning of fenofibrate as a potential ancillary immunotherapy adjunct to antiparasitic drugs, addressing inflammation to mitigate Chagas disease symptoms.

Dynamic shifts in lung cytokine patterns in post-COVID-19 interstitial lung disease patients: a pilot study

Introduction

The pathogenesis of post-COVID interstitial lung disease, marked by lung tissue scarring and functional decline, remains largely unknown.

Objectives

We aimed to elucidate the temporal cytokine/chemokine changes in bronchoalveolar lavage (BAL) from patients with post-COVID interstitial lung disease to uncover potential immune drivers of pulmonary complications.

Design

We evaluated 16 females diagnosed with post-COVID interstitial lung disease, originating from moderate to severe cases during the second epidemic wave in the Autumn of 2020, treated at the Pneumology Department of the Arad County Clinical Hospital, Romania. Their inflammatory response over time was compared to a control group.

Methods

A total of 48 BAL samples were collected over three intervals (1, 3, and 6 months) and underwent cytology, gene, and protein expression analyses for pro/anti-inflammatory lung cytokines and chemokines using reverse transcription polymerase chain reaction and enzyme-linked immunosorbent assay.

Results

One month after infection, there were significant increases in the levels of IL-6 and IL-8. These levels decreased gradually over the course of 6 months but were still higher than those seen in control. Interferon-gamma and tumor necrosis factor alpha exhibited similar patterns. Persistent elevations were found in IL-10, IL-13, and pro-fibrotic M2 macrophages' chemokines (CCL13 and CCL18) for 6 months. Furthermore, pronounced neutrophilia was observed at 1 month post-COVID, highlighting persistent inflammation and lung damage. Neutrophil efferocytosis, aiding inflammation resolution and tissue repair, was evident at the 1-month time interval. A notable time-dependent reduction in CD28 was also noticed.

Conclusion

Our research provides insight into the immunological processes that may lead to the fibrotic changes noted in the lungs following COVID-19.

The potential of short-chain fatty acid epigenetic regulation in chronic low-grade inflammation and obesity

Obesity and chronic low-grade inflammation, often occurring together, significantly contribute to severe metabolic and inflammatory conditions like type 2 diabetes (T2D), cardiovascular disease (CVD), and cancer. A key player is elevated levels of gut dysbiosis-associated lipopolysaccharide (LPS), which disrupts metabolic and immune signaling leading to metabolic endotoxemia, while short-chain fatty acids (SCFAs) beneficially regulate these processes during homeostasis. SCFAs not only safeguard the gut barrier but also exert metabolic and immunomodulatory effects via G protein-coupled receptor binding and epigenetic regulation. SCFAs are emerging as potential agents to counteract dysbiosis-induced epigenetic changes, specifically targeting metabolic and inflammatory genes through DNA methylation, histone acetylation, microRNAs (miRNAs), and long non-coding RNAs (lncRNAs). To assess whether SCFAs can effectively interrupt the detrimental cascade of obesity and inflammation, this review aims to provide a comprehensive overview of the current evidence for their clinical application. The review emphasizes factors influencing SCFA production, the intricate connections between metabolism, the immune system, and the gut microbiome, and the epigenetic mechanisms regulated by SCFAs that impact metabolism and the immune system.

Single-cell ATAC sequencing identifies sleepy macrophages during reciprocity of cytokines in L. major infection

The hallmark characteristic of macrophages lies in their inherent plasticity, allowing them to adapt to dynamic microenvironments. Leishmania strategically modulates the phenotypic plasticity of macrophages, creating a favorable environment for intracellular survival and persistent infection through regulatory cytokine such as interleukin (IL)-10. Nevertheless, these effector cells can counteract infection by modulating crucial cytokines like IL-12 and key components involved in its production. Using sophisticated tool of single-cell assay for transposase accessible chromatin (ATAC) sequencing, we systematically examined the regulatory axis of IL-10 and IL-12 in a time-dependent manner during Leishmania major infection in macrophages Our analysis revealed the cellular heterogeneity post-infection with the regulators of IL-10 and IL-12, unveiling a reciprocal relationship between these cytokines. Notably, our significant findings highlighted the presence of sleepy macrophages and their pivotal role in mediating reciprocity between IL-10 and IL-12. To summarize, the roles of cytokine expression, transcription factors, cell cycle, and epigenetics of host cell machinery were vital in identification of sleepy macrophages, which is a transient state where transcription factors controlled the epigenetic remodeling and expression of genes involved in pro-inflammatory cytokine expression and recruitment of immune cells.IMPORTANCELeishmaniasis is an endemic affecting 99 countries and territories globally, as outlined in the 2022 World Health Organization report. The disease's severity is compounded by compromised host immune systems, emphasizing the pivotal role of the interplay between parasite and host immune factors in disease regulation. In instances of cutaneous leishmaniasis induced by L. major, macrophages function as sentinel cells. Our findings indicate that the plasticity and phenotype of macrophages can be modulated to express a cytokine profile involving IL-10 and IL-12, mediated by the regulation of transcription factors and their target genes post-L. major infection in macrophages. Employing sophisticated methodologies such as single-cell ATAC sequencing and computational genomics, we have identified a distinctive subset of macrophages termed "sleepy macrophages." These macrophages exhibit downregulated housekeeping genes while expressing a unique set of variable features. This data set constitutes a valuable resource for comprehending the intricate host-parasite interplay during L. major infection.

Getting everyone to agree on gene signatures for murine macrophage polarization in vitro

Macrophages, key players in the innate immune system, showcase remarkable adaptability. Derived from monocytes, these phagocytic cells excel in engulfing and digesting pathogens and foreign substances as well as contributing to antigen presentation, initiating and regulating adaptive immunity. Macrophages are highly plastic, and the microenvironment can shaper their phenotype leading to numerous distinct polarized subsets, exemplified by the two ends of the spectrum: M1 (classical activation, inflammatory) and M2 (alternative activation, anti-inflammatory). RNA sequencing (RNA-Seq) has revolutionized molecular biology, offering a comprehensive view of transcriptomes. Unlike microarrays, RNA-Seq detects known and novel transcripts, alternative splicing, and rare transcripts, providing a deeper understanding of genome complexity. Despite the decreasing costs of RNA-Seq, data consolidation remains limited, hindering noise reduction and the identification of authentic signatures. Macrophages polarization is routinely ascertained by qPCR to evaluate those genes known to be characteristic of M1 or M2 skewing. Yet, the choice of these genes is literature- and experience-based, lacking therefore a systematic approach. This manuscript builds on the significant increase in deposited RNA-Seq datasets to determine an unbiased and robust murine M1 and M2 polarization profile. We now provide a consolidated list of global M1 differentially expressed genes (i.e. robustly modulated by IFN-γ, LPS, and LPS+ IFN-γ) as well as consolidated lists of genes modulated by each stimulus (IFN-γ, LPS, LPS+ IFN-γ, and IL-4).

Lipolysis inhibition as a treatment of clinical ketosis in dairy cows: Effects on adipose tissue metabolic and immune responses

Dairy cows with clinical ketosis (CK) exhibit excessive adipose tissue (AT) lipolysis and systemic inflammation. Lipolysis in cows can be induced by the canonical (hormonally induced) and inflammatory lipolytic pathways. Currently, the most common treatment for CK is oral propylene glycol (PG); however, PG does not reduce lipolysis or inflammation. Niacin (NIA) can reduce the activation of canonical lipolysis, whereas cyclooxygenase inhibitors such as flunixin meglumine (FM) can limit inflammation and inhibit the inflammatory lipolytic pathway. The objective of this study was to determine the effects of including NIA and FM in the standard PG treatment for postpartum CK on AT function. Multiparous Jersey cows [n = 18; 7.1 (SD = 3.8) DIM] were selected from a commercial dairy. Inclusion criteria were CK symptoms (lethargy, depressed appetite, and drop in milk yield) and high blood levels of β-hydroxybutyrate (BHB ≥ 1.2 mmol/L). Cows with CK were randomly assigned to one of 3 treatments: 1) PG: 310 g administered orally once per d for 5 d, 2) PG+NIA: 24 g administered orally oral once per d for 3 d, 3) PG+NIA+FM: 1.1 mg/kg administered IV once per day for 3 d. Healthy cows (HC; n = 6) matched by lactation and DIM (±2 d) were sampled. Subcutaneous AT explants were collected at d 0 (d0) and 7 (d7) relative to enrollment. To assess AT insulin sensitivity, explants were treated with insulin (INS = 1 µL/L) during lipolysis stimulation with a β-adrenergic receptor agonist (isoproterenol, ISO = 1 µM). Lipolysis was quantified by glycerol release in the media. Lipid mobilization and inflammatory gene networks were evaluated using real-time qPCR. Protein biomarkers of lipolysis, insulin signaling, and AT inflammation, including HSL, AKT, and ERK1/2, were quantified by capillary immunoassays. Flow cytometry of AT cellular components was used to characterize macrophage inflammatory phenotypes. Statistical significance was determined by a non-parametric t-test when 2 groups (HC vs CK) were analyzed and an ANOVA test with Tukey adjustment when 3 treatment groups (PG vs PGNIA vs PGNIAFM) were evaluated. At d0, AT from CK cows showed higher mRNA expression of lipolytic enzymes ABHD5, LIPE, and LPL, as well as increased phosphorylation of the lipase HSL (pHSL) compared with HC. At d0, INS reduced lipolysis by 41 ± 8% in AT from HC, while CK cows were unresponsive (-2.9 ± 4%). AT from CK cows exhibited reduced Akt phosphorylation compared with HC. CK had increased AT expression of inflammatory gene markers, including CCL2, IL8, IL10, TLR4, and TNF, along with ERK1/2 phosphorylation. AT from CK cows showed increased macrophage infiltration compared with HC. By d7, AT from PGNIAFM cows had a more robust response to INS, as evidenced by reduced glycerol release (36.5 ± 8% compared with PG, 26.9 ± 7%, and PGNIA, 7.4 ± 8%) and enhanced phosphorylation of Akt. By d7, PGNIAFM cows presented lower inflammatory markers, including ERK1/2 phosphorylation and reduced macrophage infiltration, compared with PG and PGNIA. These data suggest that including NIA and FM in CK treatment improves AT insulin sensitivity and reduces AT inflammation and macrophage infiltration.

Oxalate disrupts monocyte and macrophage cellular function via Interleukin-10 and mitochondrial reactive oxygen species (ROS) signaling

Oxalate is a small compound found in certain plant-derived foods and is a major component of calcium oxalate (CaOx) kidney stones. Individuals that consume oxalate enriched meals have an increased risk of forming urinary crystals, which are precursors to CaOx kidney stones. We previously reported that a single dietary oxalate load induces nanocrystalluria and reduces monocyte cellular bioenergetics in healthy adults. The purpose of this study was to extend these investigations to identify specific oxalate-mediated mechanisms in monocytes and macrophages. We performed RNA-Sequencing analysis on monocytes isolated from healthy subjects exposed to a high oxalate (8 mmol) dietary load. RNA-sequencing revealed 1,198 genes were altered and Ingenuity Pathway Analysis demonstrated modifications in several pathways including Interleukin-10 (IL-10) anti-inflammatory cytokine signaling, mitochondrial metabolism and function, oxalic acid downstream signaling, and autophagy. Based on these findings, we hypothesized that oxalate induces mitochondrial and lysosomal dysfunction in monocytes and macrophages via IL-10 and reactive oxygen species (ROS) signaling which can be reversed with exogenous IL-10 or Mitoquinone (MitoQ; a mitochondrial targeted antioxidant). We exposed monocytes and macrophages to oxalate in an in-vitro setting which caused oxidative stress, a decline in IL-10 cytokine levels, mitochondrial and lysosomal dysfunction, and impaired autophagy in both cell types. Administration of exogenous IL-10 and MitoQ attenuated these responses. These findings suggest that oxalate impairs metabolism and immune response via IL-10 signaling and mitochondrial ROS generation in both monocytes and macrophages which can be potentially limited or reversed. Future studies will examine the benefits of these therapies on CaOx crystal formation and growth in vivo.

Loss of HES1 expression is associated with extracellular matrix remodeling and tumor immune suppression in KRAS mutant colon adenocarcinomas

The loss of HES1, a canonical Notch signaling target, may cooperate with KRAS mutations to remodel the extracellular matrix and to suppress the anti-tumor immune response. While HES1 expression is normal in benign hyperplastic polyps and normal colon tissue, HES1 expression is often lost in sessile serrated adenomas/polyps (SSAs/SSPs) and colorectal cancers (CRCs) such as those right-sided CRCs that commonly harbor BRAF or KRAS mutations. To develop a deeper understanding of interaction between KRAS and HES1 in colorectal carcinogenesis, we selected microsatellite stable (MSS) and KRAS mutant or KRAS wild type CRCs that show aberrant expression of HES1 by immunohistochemistry. By comparing the transcriptional landscapes of microsatellite stable (MSS) CRCs with or without nuclear HES1 expression, we investigated differentially expressed genes and activated pathways. We identified pathways and markers in the extracellular matrix and immune microenvironment that are associated with mutations in KRAS. We found that loss of HES1 expression positively correlated with matrix remodeling and epithelial-mesenchymal transition but negatively correlated with tumor cell proliferation. Furthermore, loss of HES1 expression in KRAS mutant CRCs correlates with a higher M2 macrophage polarization and activation of IL6 and IL10 immunosuppressive signature. Identifying these HES1-related markers may be useful for prognosis stratification and developing treatment for KRAS-mutant CRCs.

Monitoring regulatory T cells as a prognostic marker in lung transplantation

Lung transplantation is the major surgical procedure, which restores normal lung functioning and provides years of life for patients suffering from major lung diseases. Lung transplant recipients are at high risk of primary graft dysfunction, and chronic lung allograft dysfunction (CLAD) in the form of bronchiolitis obliterative syndrome (BOS). Regulatory T cell (Treg) suppresses effector cells and clinical studies have demonstrated that Treg levels are altered in transplanted lung during BOS progression as compared to normal lung. Here, we discuss levels of Tregs/FOXP3 gene expression as a crucial prognostic biomarker of lung functions during CLAD progression in clinical lung transplant recipients. The review will also discuss Treg mediated immune tolerance, tissue repair, and therapeutic strategies for achieving in-vivo Treg expansion, which will be a potential therapeutic option to reduce inflammation-mediated graft injuries, taper the toxic side effects of ongoing immunosuppressants, and improve lung transplant survival rates.

Tumor Growth Ameliorates Cardiac Dysfunction

Heart failure and cancer are the deadliest diseases worldwide. Murine models for cardiac remodeling and heart failure demonstrate that cardiac dysfunction promotes cancer progression and metastasis spread. Yet, no information is available on whether and how tumor progression affects cardiac remodeling. Here, we examined cardiac remodeling following transverse aortic constriction (TAC) in the presence or absence of proliferating cancer cells. We show that tumor-bearing mice, of two different cancer cell lines, display reduced cardiac hypertrophy, lower fibrosis and improved cardiac contractile function following pressure overload induced by TAC surgery. Integrative analysis of qRT-PCR, flow cytometry and immunofluorescence identified tumor-dependent M1-to-M2 polarization in the cardiac macrophage population as a mediator of the beneficial tumor effect on the heart. Importantly, tumor-bearing mice lacking functional macrophages fail to improve cardiac function and display sustained fibrosis.

Advance in topical biomaterials and mechanisms for the intervention of pressure injury

Pressure injuries (PIs) are localized tissue damage resulting from prolonged compression or shear forces on the skin or underlying tissue, or both. Different stages of PIs share common features include intense oxidative stress, abnormal inflammatory response, cell death, and subdued tissue remodeling. Despite various clinical interventions, stage 1 or stage 2 PIs are hard to monitor for the changes of skin or identify from other disease, whereas stage 3 or stage 4 PIs are challenging to heal, painful, expensive to manage, and have a negative impact on quality of life. Here, we review the underlying pathogenesis and the current advances of biochemicals in PIs. We first discuss the crucial events involved in the pathogenesis of PIs and key biochemical pathways lead to wound delay. Then, we examine the recent progress of biomaterials-assisted wound prevention and healing and their prospects.

Modulation of Alveolar Macrophage Activity by Eugenol Attenuates Cigarette-Smoke-Induced Acute Lung Injury in Mice

This study investigates the role of eugenol (EUG) on CS-induced acute lung injury (ALI) and how this compound is able to modulate macrophage activity. C57BL/6 mice were exposed to 12 cigarettes/day/5days and treated 15 min/day/5days with EUG. Rat alveolar macrophages (RAMs) were exposed to CSE (5%) and treated with EUG. In vivo, EUG reduced morphological changes inflammatory cells, oxidative stress markers, while, in vitro, it induced balance in the oxidative stress and reduced the pro-inflammatory cytokine release while increasing the anti-inflammatory one. These results suggest that eugenol reduced CS-induced ALI and acted as a modulator of macrophage activity.

Implication of the Transmembrane Domain in the Interleukin 10 Receptor Platform Oligomerisation

Interleukin 10 (IL-10) exerts anti-inflammatory and immune regulatory roles through its fixation to the IL-10 receptor (IL-10R). The two subunits (IL-10Rα and IL-10Rβ) organise themselves to form a hetero-tetramer to induce the activation of the transcription factor STAT3. We analysed the activation patterns of the IL-10R, especially the contribution of the transmembrane (TM) domain of the IL-10Rα and IL-10Rβ subunits, as evidence accumulates that this short domain has tremendous implications in receptor oligomerisation and activation. We also addressed whether targeting the TM domain of IL-10R with peptides mimicking the TM sequences of the subunits translates into biological consequences. The results illustrate the involvement of the TM domains from both subunits in receptor activation and feature a distinctive amino acid crucial for the interaction. The TM peptide targeting approach also appears to be suitable for modulating the activation of the receptor through its action on the dimerization capabilities of the TM domains and thereby constitutes a potential new strategy for the modulation of the inflammation in pathologic contexts.

Natriuretic-like Peptide Lebetin 2 Mediates M2 Macrophage Polarization in LPS-Activated RAW264.7 Cells in an IL-10-Dependent Manner

Snake natriuretic peptide (NP) Lebetin 2 (L2) has been shown to improve cardiac function and reduce fibrosis as well as inflammation by promoting M2-type macrophages in a reperfused myocardial infarction (MI) model. However, the inflammatory mechanism of L2 remains unclear. Therefore, we investigated the effect of L2 on macrophage polarization in lipopolysaccharide (LPS)-activated RAW264.7 cells in vitro and explored the associated underlying mechanisms. TNF-α, IL-6 and IL-10 levels were assessed using an ELISA assay, and M2 macrophage polarization was determined by flow cytometry. L2 was used at non-cytotoxic concentrations determined by a preliminary MTT cell viability assay, and compared to B-type natriuretic peptide (BNP). In LPS-activated cells, both peptides reduced TNF-α and IL-6 release compared to controls. However, only L2 increased IL-10 release in a sustained manner and promoted downstream M2 macrophage polarization. Pretreatment of LPS-activated RAW264.7 cells with the selective NP receptor (NPR) antagonist isatin abolished both IL-10 and M2-like macrophage potentiation provided by L2. In addition, cell pretreatment with the IL-10 inhibitor suppressed L2-induced M2 macrophage polarization. We conclude that L2 exerts an anti-inflammatory response to LPS by regulating the release of inflammatory cytokines via stimulating of NP receptors and promoting M2 macrophage polarization through activation of IL-10 signaling.

Role of MHC class I pathways in Mycobacterium tuberculosis antigen presentation

MHC class I antigen processing is an underappreciated area of nonviral host–pathogen interactions, bridging both immunology and cell biology, where the pathogen’s natural life cycle involves little presence in the cytoplasm. The effective response to MHC-I foreign antigen presentation is not only cell death but also phenotypic changes in other cells and stimulation of the memory cells ready for the next antigen reoccurrence. This review looks at the MHC-I antigen processing pathway and potential alternative sources of the antigens, focusing on Mycobacterium tuberculosis (Mtb) as an intracellular pathogen that co-evolved with humans and developed an array of decoy strategies to survive in a hostile environment by manipulating host immunity to its own advantage. As that happens via the selective antigen presentation process, reinforcement of the effective antigen recognition on MHC-I molecules may stimulate subsets of effector cells that act earlier and more locally. Vaccines against tuberculosis (TB) could potentially eliminate this disease, yet their development has been slow, and success is limited in the context of this global disease’s spread. This review’s conclusions set out potential directions for MHC-I-focused approaches for the next generation of vaccines.

Multi-modulation of immune-inflammatory response using bioactive molecule-integrated PLGA composite for spinal fusion

Despite current developments in bone substitute technology for spinal fusion, there is a lack of adequate materials for bone regeneration in clinical applications. Recombinant human bone morphogenetic protein-2 (rhBMP-2) is commercially available, but a severe inflammatory response is a known side effect. Bone graft substitutes that enhance osteogenesis without adverse effects are needed. We developed a bioactive molecule-laden PLGA composite with multi-modulation for bone fusion. This bioresorbable composite scaffold was considered for bone tissue engineering. Among the main components, magnesium hydroxide (MH) aids in reduction of acute inflammation affecting disruption of new bone formation. Decellularized bone extracellular matrix (bECM) and demineralized bone matrix (DBM) composites were used for osteoconductive and osteoinductive activities. A bioactive molecule, polydeoxyribonucleotide (PDRN, PN), derived from trout was used for angiogenesis during bone regeneration. A nano-emulsion method that included Span 80 was used to fabricate bioactive PLGA-MH-bECM/DBM-PDRN (PME2/PN) composite to obtain a highly effective and safe scaffold. The synergistic effect provided by PME2/PN improved not only osteogenic and angiogenic gene expression for bone fusion but also improved immunosuppression and polarization of macrophages that were important for bone tissue repair, using a rat model of posterolateral spinal fusion (PLF). It thus had sufficient biocompatibility and bioactivity for spinal fusion.

Bacteria and macrophages in the tumor microenvironment

Cancer and microbial infections are significant worldwide health challenges. Numerous studies have demonstrated that bacteria may contribute to the emergence of cancer. In this review, we assemble bacterial species discovered in various cancers to describe their variety and specificity. The relationship between bacteria and macrophages in cancer is also highlighted, and we look for ample proof to establish a biological basis for bacterial-induced macrophage polarization. Finally, we quickly go over the potential roles of metabolites, cytokines, and microRNAs in the regulation of the tumor microenvironment by bacterially activated macrophages. The complexity of bacteria and macrophages in cancer will be revealed as we gain a better understanding of their pathogenic mechanisms, which will lead to new therapeutic approaches for both inflammatory illnesses and cancer.

CCL20/CCR6 Mediated Macrophage Activation and Polarization Can Promote Adenoid Epithelial Inflammation in Adenoid Hypertrophy

Background

Adenoid hypertrophy (AH) is a chronic or acute obstruction-related ailment of the upper respiratory tract that arises as an inflammatory response to exposure of bacteria, viruses or allergies. Activation and polarization of macrophages are key processes in inflammation-related disorders like AH and CCL20/CCR6 axis is a critical therapeutic target.

Purpose

To determine that CCL20/CCR6 mediated macrophage activation and polarization can promote adenoid epithelial inflammation in AH.

Methods

To support this claim, CCL20 and CCR6 expressions were studied in clinical AH samples. In addition, the expressions of cytokines such as TNF-α, IL-1β, IL-6, IL-17, IL-10 and TGF-β were analysed. In vitro, human adenoid epithelial cells were co-cultured with polarized THP-1 and T lymphocyte H9 cells to study the expressions of several inflammatory markers.

Results

The expressions of M1 macrophage markers CD86 and IL-17 were significantly increased, whereas the expressions of M2 macrophage markers CD206 and FOXP3 were significantly decreased. The THP-1 cells were successfully polarized to M0, M1 and M2 macrophages. The survival of macrophages improved after 24 hr of induction and enhanced TGF-β expression was observed. The expressions of the inflammatory cytokines IL-6, TNF-α, IL-1β and CCL20 increased significantly.

Conclusion

Collectively, these results suggest that the CCL20/CCR6 mediated macrophage activation and polarization into M1-type macrophages can promote adenoid epithelial inflammation in AH. Further studies are warranted to determine the roles of inflammatory markers in the pathophysiology of AH and identifying potential targets.

Acid external and internal environment exchange the Oreochromis niloticus tissue immune gene expression compared to the mouse macrophage polarization model

The water environment plays an important role in animal physiology. In this study, we sought to evaluate the effect of the acid environment on the Oreochromis niloticus (Nile tilapia) internal microenvironment immune response compare to the mouse macrophage model (J77A.1). The acid environment treated mouse macrophage J774A.1 model have shown that acidic treatment is able to polarize macrophages into M2-like macrophages via an increase in Ym1, Tgm2, Arg1, Fizz1, and IL-10 expression. Metabolic analysis of mouse macrophages (J774A.1) at pH 2 vs. pH 7 and pH 4 vs. pH 7 have been shown to promote the expression of intracellular acetylcholine, choline, prochlorperazine, L-leucine, and bisphenol A,2-amino-3-methylimidazo[4,5-f] quinolone metabolites in the M2-like macrophage. Immune gene expression of the O. niloticus spleen and liver treated at pH 2, 4, and 7 was shown to reduce TNF-α, IL-1 β, IL-8, and IL-12 expression compared to pH 7 treatment. Immune gene was induced in O. niloticus following culture at pH 5, 6, and 7 fresh water environment. Taken together, we found that the acid internal environment polarizes tissues into an M2 macrophage developmental microenvironment. However, if the external environment is acid, tissues are exposed to an M1 macrophage developmental microenvironment.

Modulation of TDM-induced granuloma pathology by human lactoferrin: a persistent effect in mice

Lactoferrin (LTF), an iron binding protein, is known to exhibit immune modulatory effects on pulmonary pathology during insult-induced models of primary Mycobacterium tuberculosis (Mtb) infection. The effects of LTF correlate with modulation of the immune related development of the pathology, and altering of the histological nature of the physically compact and dense lung granuloma in mice. Specifically, a recombinant human version of LTF limits immediate progression of granulomatous severity following administration of the Mtb cell wall mycolic acid, trehalose 6,6'-dimycolate (TDM), in part through reduced pro-inflammatory responses known to control these events. This current study investigates a limited course of LTF to modulate not only initiation, but also maintenance and resolution of pathology post development of the granulomatous response in mice. Comparison is made to a fusion of LTF with the Fc domain of IgG2 (FcLTF), which is known to extend LTF half-life in circulation. TDM induced granulomas were examined at extended times post insult (day 7 and 14). Both LTF and the novel FcLTF exerted sustained effects on lung granuloma pathology. Reduction of pulmonary pro-inflammatory cytokines TNF-α and IL-1β occurred, correlating with reduced pathology. Increase in IL-6, known to regulate granuloma maintenance, was also seen with the LTFs. The FcLTF demonstrated greater impact than the recombinant LTF, and was superior in limiting damage to pulmonary tissues while limiting residual inflammatory cytokine production.

Manipulation and exploitation of host immune system by pathogenic Mycobacterium tuberculosis for its advantage

Mycobacterium tuberculosis (Mtb) can become a long-term infection by evading the host immune response. Coevolution of Mtb with humans has resulted in its ability to hijack the host's immune systems in a variety of ways. So far, every Mtb defense strategy is essentially dependent on a subtle balance that, if shifted, can promote Mtb proliferation in the host, resulting in disease progression. In this review, the authors summarize many important and previously unknown mechanisms by which Mtb evades the host immune response. Besides recently found strategies by which Mtb manipulates the host molecular regulatory machinery of innate and adaptive immunity, including the intranuclear regulatory machinery, costimulatory molecules, the ubiquitin system and cellular intrinsic immune components will be discussed. A holistic understanding of these immune-evasion mechanisms is of foremost importance for the prevention, diagnosis and treatment of tuberculosis and will lead to new insights into tuberculosis pathogenesis and the development of more effective vaccines and treatment regimens.

Tollip Orchestrates Macrophage Polarization to Alleviate Intestinal Mucosal Inflammation

BACKGROUND AND AIMS

Regulation of macrophage polarization is a promising strategy for treating inflammatory bowel disease [IBD]. Tollip is an important negative regulator of Toll-like receptor [TLR]-mediated innate immunity with downregulated expression in the colon tissues of patients with IBD. This study aimed to regulate the expression of Tollip to affect macrophage polarization.

METHODS

A molecular, targeted immunotherapy method was developed by linking mannose-modified trimethyl chitosan [MTC] with Tollip-expressing plasmids via ionic cross-linking, forming MTC-Tollip nanoparticles with a targeting function. MTC-Tollip selectively targeted mouse intestinal macrophages to regulate the polarization of macrophages for mucosal repair.

RESULTS

Orally administered MTC-Tollip significantly elevated Tollip expression in intestinal tissue. Compared with MTC-negative control [NC]-treated mice in which colitis was induced with dextran sodium sulphate [DSS], the MTC-Tollip nanoparticle-treated mice exhibited decreased body weight loss and colon shortening, lower proinflammatory cytokine expression in colon tissues, and greater mucosal barrier integrity. MTC-Tollip treatment decreased TNF-α and iNOS expression but increased CD206 and Arg-1 expression in colon tissue. Tollip overexpression in mouse peritoneal macrophages inhibited lipopolysaccharide [LPS]-induced proinflammatory cytokine production and promoted IL-4-induced M2 expression. The progression of peritoneal macrophages extracted from Tollip-/- mice confirmed the effect of Tollip on macrophage polarization. Western blots showed that Tollip overexpression attenuated the upregulation of TLR pathway-associated targets in M1 macrophages.

CONCLUSIONS

MTC nanoparticles can be 'intelligent' carriers in immunotherapy. The modulation of Tollip expression in macrophages may be a novel treatment approach for IBD.

Targeted Radionuclide Therapy with Low and High-Dose Lutetium-177-Labeled Single Domain Antibodies Induces Distinct Immune Signatures in a Mouse Melanoma Model

Targeted radionuclide therapy (TRT) using probes labeled with Lutetium-177 (177Lu) represents a new and growing type of cancer therapy. We studied immunologic changes in response to TRT with 177Lu labeled anti-human CD20 camelid single domain antibodies (sdAb) in a B16-melanoma model transfected to express human CD20, the target antigen, and ovalbumin, a surrogate tumor antigen. High-dose TRT induced melanoma cell death, calreticulin exposure, and ATP-release in vitro. Melanoma-bearing mice received fractionated low and high-dose TRT via tumor targeting anti-human CD20 sdAbs, as opposed to control sdAbs. Tumor growth was delayed with both doses. Low- and high-dose TRT increased IL10 serum levels. Low-dose TRT also decreased CCL5 serum levels. At the tumor, high-dose TRT induced a type I IFN gene signature, while low-dose TRT induced a proinflammatory gene signature. Low- and high-dose TRT increased the percentage of PD-L1pos and PD-L2pos myeloid cells in tumors with a marked increase in alternatively activated macrophages after high-dose TRT. The percentage of tumor-infiltrating T cells was not changed, yet a modest increase in ovalbumin-specific CD8pos T-cells was observed after low-dose TRT. Contradictory, low and high-dose TRT decreased CD4pos Th1 cells in addition to double negative T cells. In conclusion, these data suggest that low and high-dose TRT induce distinct immunologic changes, which might serve as an anchoring point for combination therapy.

IL‑10/IL‑10 receptor 1 pathway promotes the viability and collagen synthesis of pulmonary fibroblasts originated from interstitial pneumonia tissues

Interstitial pneumonia is a pulmonary interstitial inflammatory and fibrosis disease with a variety of causes that causes respiratory disorders and threatens the lives of patients. The present study aimed to investigate the expression of interleukin (IL)-10 in peripheral blood of patients with interstitial pneumonia and its biological functions in pulmonary fibroblasts. A total of 42 patients with idiopathic pulmonary fibrosis (IPF) and 20 healthy subjects were included. ELISA was used to determine IL-10 concentration in serum from the patients and healthy subjects. Primary fibroblasts were isolated from lung tissue successfully and determined by morphology. The CCK-8 assay was performed to determine the effect of IL-10 expression on cell viability. Western blotting was used to determine COL1a1, COL1a2 and IL-10R1 protein expression. Flow cytometry was used for cell cycle analysis and to determine the number of IL-10⁺ cells. Expression of IL-10 in serum from IPF patients was higher compared to that from healthy subjects. IL-10 promoted the viability and collagen synthesis and secretion of MRC-5 cells and primary pulmonary fibroblasts. IL-10 and IL-10 receptor (R) 1 served regulatory roles in the viability and collagen synthesis of MRC-5 cells. The ratio of peripheral mononuclear lymphocytes with positive expression of IL-10 was elevated in peripheral blood from patients with IPF. The present study demonstrated that IL-10 expression in peripheral blood of patients with IPF is increased significantly compared with healthy subjects. Activation of the IL-10/IL-10R1 signaling pathway promoted the viability and collagen synthesis and secretion of pulmonary fibroblasts, leading to pulmonary fibrosis. The present study provided experimental basis for further understanding the development mechanism of pulmonary fibrosis.

Physically Cross-Linked DNA Hydrogel-Based Sustained Cytokine Delivery for In Situ Diabetic Alveolar Bone Rebuilding

The development of a biodegradable and shape-adaptable bioscaffold that can enhance local cytokine retention and bioactivity is essential for the application of immunotherapy in periodontal diseases. Here, we report a biodegradable, anti-inflammatory, and osteogenic ILGel that uses a physically cross-linked DNA hydrogel as a soft bioscaffold for the long-term sustained release of cytokine interleukin-10 (IL-10) to accelerate diabetic alveolar bone rebuilding. Porous microstructures of ILGel favored the encapsulation of IL-10 and maintained IL-10 bioactivity for at least 7 days. ILGel can be gradually degraded or hydrolyzed under physiological conditions, avoiding the potential undesired side effects on dental tissues. Long-term sustained release of bioactive IL-10 from ILGel not only promoted M2 macrophage polarization and attenuated periodontal inflammation but also triggered osteogenesis of mesenchymal stem cells (MSCs), leading to accelerated alveolar bone formation and healing of alveolar bone defects under diabetic conditions in vivo. ILGel treatment significantly accelerated the defect healing rate of diabetic alveolar injury up to 93.42 ± 4.6% on day 21 post treatment compared to that of free IL-10 treatment (63.30 ± 7.39%), with improved trabecular architectures. Our findings imply the potential application of the DNA hydrogel as the bioscaffold for cytokine-based immunotherapy in diabetic alveolar bone injury and other periodontal diseases.

β-elemene regulates M1-M2 macrophage balance through the ERK/JNK/P38 MAPK signaling pathway

Macrophages are classified into classically activated M1 macrophages and alternatively activated M2 macrophages, and the two phenotypes of macrophages are present during the development of various chronic diseases, including obesity-induced inflammation. In the present study, β-elemene, which is contained in various plant substances, is predicted to treat high-fat diet (HFD)-induced macrophage dysfunction based on the Gene Expression Omnibus (GEO) database and experimental validation. β-elemene impacts the imbalance of M1-M2 macrophages by regulating pro-inflammatory cytokines in mouse white adipose tissue both in vitro and in vivo. In addition, the RAW 264 cell line, which are macrophages from mouse ascites, is used to identify the effects of β-elemene on inhibiting bacterial endotoxin lipopolysaccharide (LPS)-induced phosphorylation of mitogen-activated protein kinase (MAPK) pathways. These pathways both induce and are activated by pro-inflammatory cytokines, and they also participate in the process of obesity-induced inflammation. The results highlight that β-elemene may represent a possible macrophage-mediated therapeutic medicine.

β-elemene regulates the balance of proinflammatory cytokines in mouse white adipose tissue through MAPK signaling. Targets of β -elemene are predicted based on its 3D structure and include regulators of macrophage-mediated processes.

The Diagnostic Significance of CXCL13 in M2 Tumor Immune Microenvironment of Human Astrocytoma

Background: CXCL13 may act as a mediator of tumor-associated macrophage immunity during malignant progression. Objective: The present study clarifies the clinicopathological significances of CXCL13 and its corresponding trend with M2 macrophage in human astrocytoma. Methods: The predictive potential of CXCL13 was performed using 695 glioma samples derived from TCGA lower-grade glioma and glioblastoma (GBMLGG) dataset. CXCL13 and M2 biomarker CD163 were observed by immunohistochemistry in 112 astrocytoma tissues. Results: An in-depth analysis showed that CXCL13 expression was related to the poor prognosis of glioma patients (p = 0.0002) derive from TCGA analysis. High level of CXCL13 was detected in 43 (38.39%) astrocytoma and CXCL13/CD163 coexpression was expressed in 33 (29.46%) cases. The immunoreactivities of CXCL13 and CXCL13/CD163 were found in the malignant lesions, which were both significantly associated with grade, patient survival, and IDH1 mutation. Single CXCL13 and CXCL13/CD163 coexpression predicted poor overall survival in astrocytoma (p = 0.0039 and p = 0.0002, respectively). Multivariate Cox regression analyses manifested CXCL13/CD163 phenotype was a significant independent prognostic indicator of patient outcome in astrocytoma (CXCL13, p = 0.0642; CXCL13/CD163, p = 0.0368). Conclusion: CXCL13 overexpression is strongly linked to CD163+ M2 infiltration in malignant astrocytoma. CXCL13/CD163 coexpression would imply M2c-related aggressive characteristics existing in astrocytoma progression could also provide predictive trends of patient outcomes.

Reverse Adverse Immune Microenvironments by Biomaterials Enhance the Repair of Spinal Cord Injury

Spinal cord injury (SCI) is a severe and traumatic disorder that ultimately results in the loss of motor, sensory, and autonomic nervous function. After SCI, local immune inflammatory response persists and does not weaken or disappear. The interference of local adverse immune factors after SCI brings great challenges to the repair of SCI. Among them, microglia, macrophages, neutrophils, lymphocytes, astrocytes, and the release of various cytokines, as well as the destruction of the extracellular matrix are mainly involved in the imbalance of the immune microenvironment. Studies have shown that immune remodeling after SCI significantly affects the survival and differentiation of stem cells after transplantation and the prognosis of SCI. Recently, immunological reconstruction strategies based on biomaterials have been widely explored and achieved good results. In this review, we discuss the important factors leading to immune dysfunction after SCI, such as immune cells, cytokines, and the destruction of the extracellular matrix. Additionally, the immunomodulatory strategies based on biomaterials are summarized, and the clinical application prospects of these immune reconstructs are evaluated.

Self-assembling peptide gels promote angiogenesis and functional recovery after spinal cord injury in rats

Spinal cord injury (SCI) leads to disruption of the blood–spinal cord barrier, hemorrhage, and tissue edema, which impair blood circulation and induce ischemia. Angiogenesis after SCI is an important step in the repair of damaged tissues, and the extent of angiogenesis strongly correlates with the neural regeneration. Various biomaterials have been developed to promote angiogenesis signaling pathways, and angiogenic self-assembling peptides are useful for producing diverse supramolecular structures with tunable functionality. RADA16 (Ac-RARADADARARADADA-NH2), which forms nanofiber networks under physiological conditions, is a self-assembling peptide that can provide mechanical support for tissue regeneration and reportedly has diverse roles in wound healing. In this study, we applied an injectable form of RADA16 with or without the neuropeptide substance P to the contused spinal cords of rats and examined angiogenesis within the damaged spinal cord and subsequent functional improvement. Histological and immunohistochemical analyses revealed that the inflammatory cell population in the lesion cavity was decreased, the vessel number and density around the damaged spinal cord were increased, and the levels of neurofilaments within the lesion cavity were increased in SCI rats that received RADA16 and RADA16 with substance P (rats in the RADA16/SP group). Moreover, real-time PCR analysis of damaged spinal cord tissues showed that IL-10 expression was increased and that locomotor function (as assessed by the Basso, Beattie, and Bresnahan (BBB) scale and the horizontal ladder test) was significantly improved in the RADA16/SP group compared to the control group. Our findings indicate that RADA16 modified with substance P effectively stimulates angiogenesis within the damaged spinal cord and is a candidate agent for promoting functional recovery post-SCI.

Biobridge: An Outlook on Translational Bioinks for 3D Bioprinting

3D-bioprinting (3DBP) possesses several elements necessary to overcome the deficiencies of conventional tissue engineering, such as defining tissue shape a priori, and serves as a bridge to clinical translation. This transformative potential of 3DBP hinges on the development of the next generation of bioinks that possess attributes for clinical use. Toward this end, in addition to physicochemical characteristics essential for printing, bioinks need to possess proregenerative attributes, while enabling printing of stable structures with a defined biological function that survives implantation and evolves in vivo into functional tissue. With a focus on bioinks for extrusion-based bioprinting, this perspective review advocates a rigorous biology-based approach to engineering bioinks, emphasizing efficiency, reproducibility, and a streamlined translation process that places the clinical endpoint front and center. A blueprint for engineering the next generation of bioinks that satisfy the aforementioned performance criteria for various translational levels (TRL1-5) and a characterization tool kit is presented.

Tilapia Piscidin 4 (TP4) Reprograms M1 Macrophages to M2 Phenotypes in Cell Models of Gardnerella vaginalis-Induced Vaginosis

Gardnerella vaginalis is associated with bacterial vaginosis (BV). The virulence factors produced by G. vaginalis are known to stimulate vaginal mucosal immune response, which is largely driven by activated macrophages. While Tilapia piscidin 4 (TP4), an antimicrobial peptide isolated from Nile tilapia, is known to display a broad range of antibacterial functions, it is unclear whether TP4 can affect macrophage polarization in the context of BV. In this study, we used the culture supernatants from G. vaginalis to stimulate differentiation of THP-1 and RAW264.7 cells to an M1 phenotype. The treatment activated the NF-κB/STAT1 signaling pathway, induced reactive nitrogen and oxygen species, and upregulated inflammatory mediators. We then treated the induced M1 macrophages directly with a non-toxic dose of TP4 or co-cultured the M1 macrophages with TP4-treated vaginal epithelial VK2 cells. The results showed that TP4 could not only decrease pro-inflammatory mediators in the M1 macrophages, but it also enriched markers of M2 macrophages. Further, we found that direct treatment with TP4 switched M1 macrophages toward a resolving M2c phenotype via the MAPK/ERK pathway and IL-10-STAT3 signaling. Conversely, tissue repair M2a macrophages were induced by TP4-treated VK2 cells; TP4 upregulated TSG-6 in VK2 cells, which subsequently activated STAT6 and M2a-related gene expression in the macrophages. In conclusion, our results imply that TP4 may be able to attenuate the virulence of G. vaginalis by inducing resolving M2c and tissue repair M2a macrophage polarizations, suggesting a novel strategy for BV therapy.

Canine peripheral blood mononuclear cell-derived B lymphocytes pretreated with lipopolysaccharide enhance the immunomodulatory effect through macrophage polarization

BACKGROUND

Preconditioning with lipopolysaccharide (LPS) is used to improve the secretion of anti-inflammatory agents in B cells. However, there are only a few studies on canine B cells.

OBJECTIVE

This study aimed to evaluate the immune regulatory capacity of canine peripheral blood mononuclear cell-derived B cells pretreated with LPS.

METHODS

Canine B cells were isolated from canine peripheral blood mononuclear cells, which were obtained from three healthy canine donors. The B cells were preconditioned with LPS, and then cell viability and the expression of the regulatory B cell marker were assessed. Finally, RNA extraction and immunofluorescence analysis were performed.

RESULTS

LPS primed B cells expressed the interleukin (IL)-10 surface marker and immunoregulatory gene expression, such as IL-10, programmed death-ligand 1, and transforming growth factor beta. Macrophages in the inflammatory condition cocultured with primed B cells were found to have significantly down-regulated pro-inflammatory cytokine, such as tumor necrosis factor-α, and up-regulated anti-inflammatory cytokines such as IL-10. Additionally, it was revealed that co-culture with primed B cells re-polarized M1 macrophages to M2 macrophages.

CONCLUSIONS

This study revealed that LPS-primed B cells have an anti-inflammatory effect and can re-polarize macrophages, suggesting the possibility of using LPS-primed B cells as a therapeutic agent for its anti-inflammatory effects and immune modulation.

Natural Products for Regulating Macrophages M2 Polarization

Macrophages M2 polarization have been taken as an anti-inflammatory progression during inflammation. Natural plant-derived products, with potential therapeutic and preventive activities against inflammatory diseases, have received increasing attention in recent years because of their whole regulative effects and specific pharmacological activities. However, the molecular mechanisms about how different kinds of natural compounds regulate macrophages polarization still unclear. Therefore, in the current review, we summarized the detailed research progress on the active compounds derived from herbal plants with regulating effects on macrophages, especially M2 polarization. These natural occurring compounds including flavonoids, terpenoids, glycosides, lignans, coumarins, alkaloids, polyphenols and quinones. In addition, we extensively discussed the cellular mechanisms underlying the M2 polarization for each compound, which could provide potential therapeutic strategies aiming macrophages M2 polarization.

Emerging role of tumor microenvironment derived exosomes in therapeutic resistance and metastasis through epithelial-to-mesenchymal transition

The tumor microenvironment (TME) constitutes multiple cell types including cancerous and non-cancerous cells. The intercellular communication between these cells through TME derived exosomes may either enhance or suppress the tumorigenic processes. The tumor-derived exosomes could convert an anti-tumor environment into a pro-tumor environment by inducing the differentiation of stromal cells into tumor-associated cells. The exosomes from tumor-associated stromal cells reciprocally trigger epithelial-to-mesenchymal transition (EMT) in tumor cells, which impose therapeutic resistance and metastasis. It is well known that these exosomes contain the signals of EMT, but how these signals execute chemoresistance and metastasis in tumors remains elusive. Understanding the significance and molecular signatures of exosomes transmitting EMT signals would aid in developing appropriate methods of inhibiting them. In this review, we focus on molecular signatures of exosomes that shuttle between cancer cells and their stromal populations in TME to explicate their impact on therapeutic resistance and metastasis through EMT. Especially Wnt signaling is found to be involved in multiple ways of exosomal transport and hence we decipher the biomolecules of Wnt signaling trafficked through exosomes and their potential in serving as therapeutic targets.

A focused review on CB2 receptor-selective pharmacological properties and therapeutic potential of β-caryophyllene, a dietary cannabinoid

The endocannabinoid system (ECS), a conserved physiological system emerged as a novel pharmacological target for its significant role and potential therapeutic benefits ranging from neurological diseases to cancer. Among both, CB1 and CB2R types, CB2R have received attention for its pharmacological effects as antioxidant, anti-inflammatory, immunomodulatory and antiapoptotic that can be achieved without causing psychotropic adverse effects through CB1R. The ligands activate CB2R are of endogenous, synthetic and plant origin. In recent years, β-caryophyllene (BCP), a natural bicyclic sesquiterpene in cannabis as well as non-cannabis plants, has received attention due to its selective agonist property on CB2R. BCP has been well studied in a variety of pathological conditions mediating CB2R selective agonist property. The focus of the present manuscript is to represent the CB2R selective agonist mediated pharmacological mechanisms and therapeutic potential of BCP. The present narrative review summarizes insights into the CB2R-selective pharmacological properties and therapeutic potential of BCP such as cardioprotective, hepatoprotective, neuroprotective, nephroprotective, gastroprotective, chemopreventive, antioxidant, anti-inflammatory, and immunomodulator. The available evidences suggest that BCP, can be an important candidate of plant origin endowed with CB2R selective properties that may provide a pharmacological rationale for its pharmacotherapeutic application and pharmaceutical development like a drug. Additionally, given the wide availability in edible plants and dietary use, with safety, and no toxicity, BCP can be promoted as a nutraceutical and functional food for general health and well-being. Further, studies are needed to explore pharmacological and pharmaceutical opportunities for therapeutic and preventive applications of use of BCP in human diseases.

Transcranial Focused Ultrasound Stimulation Improves Neurorehabilitation after Middle Cerebral Artery Occlusion in Mice

Transcranial focused ultrasound stimulation (tFUS) regulates neural activity in different brain regions in humans and animals. However, the role of ultrasound stimulation in modulating neural activity and promoting neurorehabilitation in the ischemic brain is largely unknown. In the present study, we explored the effect of tFUS on neurological rehabilitation and the underlying mechanism. Adult male ICR mice (n=42) underwent transient middle cerebral artery occlusion. One week after brain ischemia, low frequency (0.5 MHz) tFUS was applied to stimulate the ischemic hemisphere of mice for 7 consecutive days (10 minutes daily). Brain infarct volume, neurobehavioral tests, microglia activation, IL-10 and IL-10R levels were further assessed for up to 14 days. We found that the brain infarct volume was significantly reduced in the tFUS treated mice compared to that in the non-treated mice (p<0.05). Similarly, neurological severity scores, elevated body swing test, and corner test improved in the tFUS treated mice (p<0.05). We also demonstrated that tFUS resulted in increased M2 microglia in the ischemic brain region. The expression of IL-10R and IL-10 levels were also substantially upregulated (p<0.05). We concluded that tFUS served as a unique technique to promote neurorehabilitation after brain ischemia by promoting microglia polarization and further regulating IL-10 signaling in the ischemic brain.

IL-37 inhibits M1-like macrophage activation to ameliorate temporomandibular joint inflammation through the NLRP3 pathway

OBJECTIVES

IL-37 has been identified as an important anti-inflammatory and immunosuppressive factor. This study was undertaken to explore how IL-37 affects M1/M2-like macrophage polarization and thus contributes to anti-inflammatory processes in the temporomandibular joint.

METHODS

Western blotting, quantitative real-time PCR (qRT-PCR) and immunofluorescence were used to verify the IL-37-induced polarization shift from the M1 phenotype to the M2 phenotype, and the related key pathways were analysed by western blotting. Human chondrocytes were stimulated with M1-conditioned medium (CM) or IL-37-pretreated M1-CM, and inflammatory cytokines were detected. siRNA-IL-1R8 and MCC-950 were used to investigate the mechanism underlying the anti-inflammatory effects of IL-37. Complete Freund's adjuvant-induced and disc perforation-induced inflammation models were used for in vivo studies. Haematoxylin and eosin, immunohistochemical and safranin-O staining protocols were used to analyse histological changes in the synovium and condyle.

RESULTS

Western blotting, qRT-PCR and immunofluorescence showed that IL-37 inhibited M1 marker expression and upregulated M2 marker expression. Western blotting and qRT-PCR showed that pretreatment with IL-37 suppressed inflammatory cytokine expression in chondrocytes. IL-37 inhibited the expression of NLRP3 and upregulated the expression of IL-1R8. Si-IL-1R8 and MCC-950 further confirmed that the anti-inflammatory properties of IL-37 were dependent on the presence of IL-1R8 and NLRP3. In vivo, IL-37 reduced synovial M1 marker expression and cartilage degeneration and increased M2 marker expression.

CONCLUSION

IL-37 shifting of the polarization of macrophages from the pro-inflammatory M1 phenotype to the beneficial anti-inflammatory M2 phenotype seems to be a promising therapeutic strategy for treating temporomandibular joint inflammation.

Lentiviral Interleukin-10 Gene Therapy Preserves Fine Motor Circuitry and Function After a Cervical Spinal Cord Injury in Male and Female Mice

In mammals, spinal cord injuries often result in muscle paralysis through the apoptosis of lower motor neurons and denervation of neuromuscular junctions. Previous research shows that the inflammatory response to a spinal cord injury can cause additional tissue damage after the initial trauma. To modulate this inflammatory response, we delivered lentiviral anti-inflammatory interleukin-10, via loading onto an implantable biomaterial scaffold, into a left-sided hemisection at the C5 vertebra in mice. We hypothesized that improved behavioral outcomes associated with anti-inflammatory treatment are due to the sparing of fine motor circuit components. We examined behavioral recovery using a ladder beam, tissue sparing using histology, and electromyogram recordings using intraspinal optogenetic stimulation at 2 weeks post-injury. Ladder beam analysis shows interleukin-10 treatment results in significant improvement of behavioral recovery at 2 and 12 weeks post-injury when compared to mice treated with a control virus. Histology shows interleukin-10 results in greater numbers of lower motor neurons, axons, and muscle innervation at 2 weeks post-injury. Furthermore, electromyogram recordings suggest that interleukin-10-treated animals have signal-to-noise ratios and peak-to-peak amplitudes more similar to that of uninjured controls than to that of control injured animals at 2 weeks post-injury. These data show that gene therapy using anti-inflammatory interleukin-10 can significantly reduce tissue damage and subsequent motor deficits after a spinal cord injury. Together, these results suggest that early modulation of the injury response can preserve muscle function with long-lasting benefits.

Human gingival fibroblast secretome accelerates wound healing through anti-inflammatory and pro-angiogenic mechanisms

Healing of the skin and oral mucosa utilises similar mechanisms of tissue repair, however, scarring and the rate of wound closure is vastly superior in the oral cavity suggesting differences between these two environments. One key difference is the phenotype of dermal fibroblasts compared to fibroblasts of gingival tissues. Human gingival fibroblasts (hGFs) are undifferentiated cells with multi-differentiation and self-renewal capacities. This study aimed to examine if delivering hGFs or their secretome, contained in hGF-conditioned media (hGF-CM), would improve healing of the skin and recapitulate features of oral healing. Human fibroblasts, keratinocytes and endothelial cells were first treated with hGF-CM and showed improved migration, proliferation and angiogenic functions. A significant reduction in macroscopic wound area and histologic dermal wound width, as well as an increased rate of re-epithelialisation, were observed in both hGFs and hGF-CM treated murine excisional wounds. This improvement was associated with reduced inflammation, increased angiogenesis and elevated collagen deposition. These findings demonstrate that treatment of dermal wounds with either hGFs or hGF-CM may provide beneficial gingival-like properties to dermal wounds and may be a potential opportunity for improving healing of the skin.

Regulatory role and mechanism of the inhibition of the Mcl-1 pathway during apoptosis and polarization of H37Rv-infected macrophages

BACKGROUND

Myeloid cell leukemia-1 (Mcl-1) plays an important role in the clearance of Mycobacterium tuberculosis (MTB) infection. It has the effect of anti-apoptosis, protecting macrophages that have engulfed pathogens and preventing pathogen clearance. Meanwhile, the MAPK signaling pathway plays a significant role in regulating Mcl-1 expression during tuberculosis infection. In the case of latent infection and active infection, the apoptosis and polarization of macrophages have a great influence during MTB infection, so we discussed the effect of Mcl-1 on apoptosis and polarization. Then, further discussed its mechanism.

METHODS

An infected RAW264.7 macrophage model was established to investigate the regulatory role and mechanism of the Mcl-1 pathway inhibition during apoptosis and polarization of H37Rv infection. First, Mcl-1 protein and mRNA was identified by western blotting and Real-Time Polymerase Chain Reaction (RT-PCR). RAW264.7 macrophage apoptosis was detected by flow cytometry. RT-PCR was utilized to detect Bax, Caspase-3, Cyt-c and Bcl-2 mRNA expression. Next, Then the expression levels of inflammation factors CD86, CD206, iNOS, Fizz1, IL-6, IL-10, TNF-α, and TGF-β was detected by ELISA. SEM was used to observe macrophages phenotype. Finally, Bax, Bcl-2 and Bcl-xl the expression was detected by western blotting. Confocal microscopy was used to analyze mitochondrial membrane potential using the JC-10 kit.

RESULTS

In this study, we found that inhibiting the Mcl-1 expression signaling pathway led to infection by different virulence Mycobacterium tuberculosis, as well as changes in Mcl-1 protein and mRNA expression. Concomitantly macrophage apoptosis rate also changed, While, two phenotypic states of M1 and M2 appeared in the infected cells. We also found that the mitochondrial pathway was activated, the expression of its related genes Bax, casepase3, and Cyt-c, increased, whereas that of Bcl-2 decreased, and the mitochondrial membrane depolarization function was changed.

CONCLUSIONS

We found that Mcl-1 affected the apoptosis and polarization of macrophages infected by Mycobacterium tuberculosis, mainly M1 in the early stage and M2 in the later stage. In addition, mitochondria played a crucial role in this process.

Hacking the host: exploitation of macrophage polarization by intracellular bacterial pathogens

Macrophages play an integral role in host defenses against intracellular bacterial pathogens. A remarkable plasticity allows for adaptation to the needs of the host to orchestrate versatile innate immune responses to a variety of microbial threats. Several bacterial pathogens have adapted to macrophage plasticity and modulate the classical (M1) or alternative (M2) activation bias towards a polarization state that increases fitness for intracellular survival. Here, we summarize the current understanding of the host macrophage and intracellular bacterial interface; highlighting the roles of M1/M2 polarization in host defense and the mechanisms employed by several important intracellular pathogens to modulate macrophage polarization to favor persistence or proliferation. Understanding macrophage polarization in the context of disease caused by different bacterial pathogens is important for the identification of targets for therapeutic intervention.

Blood M2a monocyte polarization and increased formyl peptide receptor 1 expression are associated with progression from latent tuberculosis infection to active pulmonary tuberculosis disease

OBJECTIVES

This study aims to explore the role of M2a polarization and formyl peptide receptor (FPR) regulation in the reactivation of Mycobacterium tuberculosis (Mtb) infection.

METHODS

M1/M2a monocyte percentage and FPR1/2/3 protein expression of blood immune cells were measured in 38 patients with sputum culture (+) active pulmonary TB disease, 18 subjects with latent TB infection (LTBI), and 28 noninfected healthy subjects (NIHS) using flow cytometry method.

RESULTS

M1 percentage was decreased in active TB versus either NIHS or LTBI group, while M2a percentage and M2a/M1 percentage ratio were increased. FPR1 expression on M1/M2a, FPR2 expression on M1, and FPR3 expression of M1 were all decreased in active TB versus LTBI group, while FPR1 over FPR2 expression ratio on NK T cell was increased in active TB versus either NIHS or LTBI group. In 11 patients with active TB disease, M1 percentage became normal again after anti-TB treatment. In vitro Mtb-specific antigen stimulation of monocytic THP-1 cells resulted in M2a polarization in association with increased FPR2 expression on M2a.

CONCLUSIONS

Increased M2a and decreased M1 phenotypes of blood monocyte may serve as a marker for active TB disease, while decreased FPR1 on blood monocyte may indicate LTBI status.

Modeling of the immune response in the pathogenesis of solid tumors and its prognostic significance

BACKGROUND

Tumor initiation and subsequent progression are usually long-term processes, spread over time and conditioned by diverse aspects. Many cancers develop on the basis of chronic inflammation; however, despite dozens of years of research, little is known about the factors triggering neoplastic transformation under these conditions. Molecular characterization of both pathogenetic states, i.e., similarities and differences between chronic inflammation and cancer, is also poorly defined. The secretory activity of tumor cells may change the immunophenotype of immune cells and modify the extracellular microenvironment, which allows the bypass of host defense mechanisms and seems to have diagnostic and prognostic value. The phenomenon of immunosuppression is also present during chronic inflammation, and the development of cancer, due to its duration, predisposes patients to the promotion of chronic inflammation. The aim of our work was to discuss the above issues based on the latest scientific insights. A theoretical mechanism of cancer immunosuppression is also proposed.

CONCLUSIONS

Development of solid tumors may occur both during acute and chronic phases of inflammation. Differences in the regulation of immune responses between precancerous states and the cancers resulting from them emphasize the importance of immunosuppressive factors in oncogenesis. Cancer cells may, through their secretory activity and extracellular transport mechanisms, enhance deterioration of the immune system which, in turn, may have prognostic implications.

How hypoxia regulate exosomes in ischemic diseases and cancer microenvironment?

Exosomes, as natural occurring vesicles, play highly important roles in the behavior and fate of ischemic diseases and different tumors. Secretion, composition, and function of exosomes are remarkably influenced by hypoxia in ischemic diseases and tumor microenvironment. Exosomes secreted from hypoxic cells affect development, growth, angiogenesis, and progression in ischemic diseases and tumors through a variety of signaling pathways. In this review article, we discuss how hypoxia affects the quantity and quality of exosomes, and review the mechanisms by which hypoxic cell-derived exosomes regulate ischemic cell behaviors in both cancerous and noncancerous cells.

IL-10 Dampens an IL-17-Mediated Periodontitis-Associated Inflammatory Network

Emerging evidence suggests comprehensive immune profiling represents a highly promising, yet insufficiently tapped approach to identify potentially prognostic signatures for periodontitis. In this report, we agnostically identified a periodontitis-associated inflammatory expression network with multiple biomarkers identified within gingival crevicular fluid samples from study participants by applying principal component analysis. We identified an IL-17-dominated trait that is associated with periodontal disease and is inversely modified by the level of IL-10. IL-10 mitigated chemokine CXCL5 and CXCL1 expressions in IL-17-stimulated peripheral blood monocytic cells and peripheral blood monocytic cell-derived macrophages. Il10-deficient mice presented more bone loss, which was associated with more Il17 and IL-17-mediated chemokine and cytokine expression at the transcriptional levels in comparison with control wild-type mice in both the Porphyromonas gingivalis-induced experimental murine periodontitis and ligature-induced alveolar bone-loss models. The dampening effect of IL-10 on the excessive signaling of IL-17 appeared to be mediated by innate immune cells populations rather than by gingival epithelial cells, which are the major cell target for IL-17 signaling. Additionally, elevated IL-17 response in Il10-deficient mice specifically elicited an M1-skewing macrophage phenotype in the gingiva that was associated with the advanced bone loss in the ligature model. In summary, IL-17 dominated an inflammatory network characteristic of periodontitis, and IL-10 dampens this excessive IL-17-mediated periodontitis trait.

Host expression system modulates recombinant Hsp70 activity through post-translational modifications

The use of model organisms for recombinant protein production results in the addition of model-specific post-translational modifications (PTMs) that can affect the structure, charge, and function of the protein. The 70-kDa heat shock proteins (Hsp70) were originally described as intracellular chaperones, with ATPase and foldase activity. More recently, new extracellular activities of Hsp70 proteins (e.g. as immunomodulators) have been identified. While some studies indicate an inflammatory potential for extracellular Hsp70 proteins, others suggest an immunosuppressive activity. We hypothesized that the production of recombinant Hsp70 in different expression systems would result in the addition of different PTMs, perhaps explaining at least some of these opposing immunological outcomes. We produced and purified Mycobacterium tuberculosis DnaK from two different systems, Escherichia coli and Pichia pastoris, and analyzed by mass spectrometry the protein preparations, investigating the impact of PTMs in an in silico and in vitro perspective. The comparisons of DnaK structures in silico highlighted that electrostatic and topographical differences exist that are dependent upon the expression system. Production of DnaK in the eukaryotic system dramatically affected its ATPase activity, and significantly altered its ability to downregulate MHC II and CD86 expression on murine dendritic cells (DCs). Phosphatase treatment of DnaK indicated that some of these differences related specifically to phosphorylation. Altogether, our data indicate that PTMs are an important characteristic of the expression system, with differences that impact interactions of Hsps with their ligands and subsequent functional activities.

Extracellular Hsp70 Reduces the Pro-Tumor Capacity of Monocytes/Macrophages Co-Cultivated with Cancer Cells

Cancer cells are known to contain high levels of the heat shock protein 70 kDa (Hsp70), which mediates increased cell proliferation, escape from programmed cell death, enhanced invasion, and metastasis. A part of Hsp70 molecules may release from cancer cells and affect the behavior of adjacent stromal cells. To explore the effects of Hsp70 on the status of monocytes/macrophages in the tumor locale, we incubated human carcinoma cells of three distinct lines with normal and reduced content of Hsp70 with THP1 monocytes. Using two methods, we showed that the cells with knock-down of Hsp70 released a lower amount of protein in the extracellular medium. Three cycles of the co-cultivation of cancer and monocytic cells led to the secretion of several cytokines typical of the tumor microenvironment (TME) and to pro-cancer activation of the monocytes/macrophages as established by elevation of F4/80 and arginase-1 markers. Unexpectedly, the efficacy of epithelial–mesenchymal transition and resistance of carcinoma cells to anticancer drugs after incubation with monocytic cells were more pronounced in cells with lower Hsp70, e.g., releasing less Hsp70 into the extracellular milieu. These data suggest that Hsp70 released from tumor cells into the TME is able, together with the development of an anti-cancer immune response, to limit the conversion of a considerable part of monocytic cells to the pro-tumor phenotype.

FOXO3 Transcription Factor Regulates IL-10 Expression in Mycobacteria-Infected Macrophages, Tuning Their Polarization and the Subsequent Adaptive Immune Response

Alveolar Macrophages play a key role in the development of a robust adaptive immune response against the agent of Tuberculosis (TB), Mycobacterium tuberculosis (M.tb). However, macrophage response is often hampered by the production of IL-10, a potent suppressor of the host immune response. The secretion of IL-10 correlates with TB pathogenesis and persistence in host tissues. Concordantly, inhibition of IL-10 signaling, during BCG vaccination, confers higher protection against M.tb through a sustained Th1 and Th17 responses. Therefore, uncovering host effectors, underlying mycobacteria-induced expression of IL-10, may be beneficial toward the development of IL-10-blocking tools to be used either as adjuvants in preventive vaccination or as adjunct during standard treatment of TB. Here, we investigated the role of FOXO3 transcription factor in mycobacteria-induced secretion of IL-10. We observed that PI3K/Akt/FOXO3 axis regulates IL-10 expression in human macrophages. Knocking down of FOXO3 expression resulted in an increase of IL-10 production in BCG-infected macrophages. The gene reporter assay further confirmed the transcriptional regulation of IL-10 by FOXO3. In silico analysis identified four Forkhead binding motifs on the human IL-10 promoter, from which the typical FOXO3 one at position -203 was the major target as assessed by mutagenesis and CHIP binding assays. Further, we also observed a decrease in gene expression levels of the M1 typical markers (i.e., CD80 and CD86) in SiFOXO3-transfected macrophages while activation of FOXO3 led to the increase in the expression of CD86, MHCI, and MHCII. Finally, co-culture of human lymphocytes with siFOXO3-transfected macrophages, loaded with mycobacterial antigens, showed decreased expression of Th1/Th17 specific markers and a simultaneous increase in expression of IL-4 and IL-10. Taken together, we report for the first time that FOXO3 modulates IL-10 secretion in mycobacteria-infected macrophage, driving their polarization and the subsequent adaptive immune response. This work proposes FOXO3 as a potential target for the development of host-directed strategies for better treatment or prevention of TB.