Macrophage depletion using clodronate liposomes decreases tumorigenesis and alters gut microbiota in the AOM/DSS mouse model of colon cancer

Banxia Xiexin Decoction delays colitis-to-cancer transition by inhibiting E-cadherin/β-catenin pathway via Fusobacterium nucleatum FadA

ETHNOPHARMACOLOGICAL RELEVANCE

Colitis is an important risk factor for the occurrence of colorectal cancer (CRC), and the colonization of Fusobacterium nucleatum (Fn) in the intestines accelerates this transformation process. Banxia Xiexin Decoction (BXD), originating from Shanghanlun, is a classic prescription for treating gastrointestinal diseases. Current researches indicate that BXD can effectively delay the colitis-to-cancer transition, but it is still unclear whether it can inhibit Fn colonization to achieve this delaying effect.

AIM OF STUDY

This study explored the effect and mechanism of BXD in inhibiting Fn intestinal colonization to delay colitis-to-cancer transition.

MATERIALS AND METHODS

We constructed a mouse model of colitis-to-cancer transition by regularly gavaging Fn combined with azoxymethane (AOM)/dextran sodium sulfate (DSS), and administered BXD by gavage. We monitored the body weight of mice, measured the length and weight of their colons, and calculated the disease activity index (DAI) score. The growth status of colon tumors was observed by hematoxylin and eosin (H&E) staining, and the changes in gut microbiota in each group of mice were detected by 16S rDNA analysis. Immunohistochemistry was used to detect the expression of E-cadherin and β-catenin in colon tissues, and immunofluorescence was used to observe the infiltration of M2 macrophages in colon tissues. In cell experiments, we established a co-culture model of Fn and colon cancer cells and intervened with BXD-containing serum. Malignant behaviors such as cell proliferation, invasion, and migration were detected, as well as changes in their cell cycle. We examined the protein levels of E-cadherin, β-catenin, Axin2, and Cyclin D1 in each group were detected by Western blot. We used US1 strain (fadA-) as a control and observed the effects of BXD-containing serum on Fn attachment and invasion of colon cancer cells through attachment and invasion experiments.

RESULTS

BXD can inhibit the colitis-to-cancer transition in mice infected with Fn, reduce crypt structure damage, improve gut microbiota dysbiosis, upregulate E-cadherin and decrease β-catenin expression, and reduce infiltration of M2 macrophages, thus inhibiting the process of colitis-to-cancer transition. Cell experiments revealed that BXD-containing serum can inhibit the proliferation, migration, and invasion of colon cancer cells infected with Fn and regulate their cell cycle. More importantly, we found that BXD-containing serum can inhibit the binding of Fn's FadA adhesin to E-cadherin, reduce Fn's attachment and invasion of colon cancer cells, thereby downregulating the E-cadherin/β-catenin signaling pathway.

CONCLUSIONS

These findings show that BXD can inhibit Fn colonization by interfering with the binding of FadA to E-cadherin, reducing the activation of the E-cadherin/β-catenin signaling pathway, and ultimately delaying colitis-to-cancer transition.

Gut microbiota as a key regulator of intestinal mucosal immunity

Gut microbiota is a complex microbial community with the ability of maintaining intestinal health. Intestinal homeostasis largely depends on the mucosal immune system to defense external pathogens and promote tissue repair. In recent years, growing evidence revealed the importance of gut microbiota in shaping intestinal mucosal immunity. Therefore, according to the existing findings, this review first provided an overview of intestinal mucosal immune system before summarizing the regulatory roles of gut microbiota in intestinal innate and adaptive immunity. Specifically, this review delved into the gut microbial interactions with the cells such as intestinal epithelial cells (IECs), macrophages, dendritic cells (DCs), neutrophils, and innate lymphoid cells (ILCs) in innate immunity, and T and B lymphocytes in adaptive immunity. Furthermore, this review discussed the main effects of gut microbiota dysbiosis in intestinal diseases and offered future research prospects. The review highlighted the key regulatory roles of gut microbiota in intestinal mucosal immunity via various host-microbe interactions, providing valuable references for the development of microbial therapy in intestinal diseases.

Bifidobacterium breve-derived indole-3-lactic acid ameliorates colitis-associated tumorigenesis by directing the differentiation of immature colonic macrophages

Aim: To elucidate dynamics and functions in colonic macrophage subsets, and their regulation by Bifidobacterium breve (B. breve) and its associated metabolites in the initiation of colitis-associated colorectal cancer (CAC). Methods: Azoxymethane (AOM) and dextran sodium sulfate (DSS) were used to create a CAC model. The tumor-suppressive effect of B. breve and variations of macrophage subsets were evaluated. Intestinal macrophages were ablated to determine their role in the protective effects of B. breve. Efficacious molecules produced by B. breve were identified by non-targeted and targeted liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. The molecular mechanism was further verified in murine bone marrow-derived macrophages (BMDMs), macrophages derived from human peripheral blood mononuclear cells (hPBMCs), and demonstrated in CAC mice. Results: B. breve alleviated colitis symptoms, delayed colonic tumorigenesis, and promoted phenotypic differentiation of immature inflammatory macrophages into mature homeostatic macrophages. On the contrary, the ablation of intestinal macrophages largely annulled the protective effects of B. breve. Microbial analysis of colonic contents revealed the enrichment of probiotics and the depletion of potential pathogens following B. breve supplementation. Moreover, indole-3-lactic acid (ILA) was positively correlated with B. breve in CAC mice and highly enriched in the culture supernatant of B. breve. Also, the addition of ILA directly promoted AKT phosphorylation and restricted the pro-inflammatory response of murine BMDMs and macrophages derived from hPBMCs in vitro. The effects of ILA in murine BMDMs and macrophages derived from hPBMCs were abolished by the aryl hydrocarbon receptor (AhR) antagonist CH-223191 or the AKT inhibitor MK-2206. Furthermore, ILA could protect against tumorigenesis by regulating macrophage differentiation in CAC mice; the AhR antagonist largely abrogated the effects of B. breve and ILA in relieving colitis and tumorigenesis. Conclusion: B. breve-mediated tryptophan metabolism ameliorates the precancerous inflammatory intestinal milieu to inhibit tumorigenesis by directing the differentiation of immature colonic macrophages.

Short-chain fatty acid-producing bacterial strains attenuate experimental ulcerative colitis by promoting M2 macrophage polarization via JAK/STAT3/FOXO3 axis inactivation

BACKGROUND

Patients with inflammatory bowel disease (IBD), dysbiosis, and immunosuppression who receive fecal microbiota transplantation (FMT) from healthy donors are at an increased risk of developing bacteremia. This study investigates the efficacy of a mixture of seven short-chain fatty acid (SCFA)-producing bacterial strains (7-mix), the resulting culture supernatant mixture (mix-sup), and FMT for treating experimental ulcerative colitis (UC) and evaluates underlying mechanisms.

METHODS

Utilizing culturomics, we isolated and cultured SCFA-producing bacteria from the stool of healthy donors. We used a mouse model of acute UC induced by dextran sulfate sodium (DSS) to assess the effects of 7-mix, mix-sup, and FMT on intestinal inflammation and barrier function, microbial abundance and diversity, and gut macrophage polarization by flow cytometry, immunohistochemistry, 16S rRNA gene sequencing, and transwell assays.

RESULTS

The abundance of several SCFA-producing bacterial taxa decreased in patients with UC. Seven-mix and mix-sup suppressed the inflammatory response and enhanced intestinal mucosal barrier function in the mouse model of UC to an extent similar to or superior to that of FMT. Moreover, 7-mix and mix-sup increased the abundance of SCFA-producing bacteria and SCFA concentrations in colitic mice. The effects of these interventions on the inflammatory response and gut barrier function were mediated by JAK/STAT3/FOXO3 axis inactivation in macrophages by inducing M2 macrophage polarization in vivo and in vitro.

CONCLUSIONS

Our approach provides new opportunities to rationally harness live gut probiotic strains and metabolites to reduce intestinal inflammation, restore gut microbial composition, and expedite the development of safe and effective treatments for IBD.

Tumor-derived exosomal hyaluronidase 1 induced M2 macrophage polarization and promoted esophageal cancer progression

The communication between tumor-derived exosomes and macrophages plays an important role in facilitating the progression of tumors. However, the regulatory mechanisms by which exosomes regulate tumor progression in esophageal squamous cell carcinoma (ESCC) have not been fully elucidated. We constructed a coculture system containing an ESCC cell line and macrophages using a Transwell chamber. We isolated exosomes from the conditioned medium of cancer cells, and characterized them with transmission electron microscopy and western blotting and used then to treat macrophages. We used co-immunoprecipitation to evaluate the interaction between hyaluronidase 1 (HYAL1) and Aurora B kinase (AURKB). We evaluated HYAL1 and AURKB expression in tissues and cells with quantitative reverse-transcription polymerase chain reaction (RT-qPCR) and western blotting. We used RT-qPCR, enzyme-linked immunosorbent assay (ELISA) and flow cytometry to detect macrophage polarization. We assessed cell viability, invasion and migration with the cell counting kit-8 (CCK-8), Transwell and wound healing assays. HYAL1 was highly expressed in ESCC tissues and cells and cancer cell-derived exosomes, and exosomes can be delivered to macrophages through the cancer cell-derived exosomes. The exosomes extracted from HYAL1-overexpressed ESCC cells suppressed M1 macrophage polarization and induced M2 macrophage polarization, thereby promoting ESCC cell viability, invasion and migration. HYAL1 silencing in ESCC cells produced the opposite effects on macrophage polarization and cancer cell functions. We found that HYAL1 interacted with AURKB and further activated the phosphoinositide 3-kinase (PI3K)/AKT signaling pathway in macrophages. In conclusion, ESCC-derived exosomes containing HYAL1 facilitate M2 macrophage polarization by targeting AURKB to active the PI3K/AKT signaling pathway, which in turn promotes ESCC progression.

Tumor-Derived RAB21+ABHD12+ sEVs Drive the Premetastatic Microenvironment in the Lung

Tumor metastasis is a spatial and temporal process that starts with remodeling to generate a proper premetastatic niche in a distant tissue. Infiltration of immunosuppressive macrophages is one of the notable characteristics in the premetastatic niche, which is a fundamental requirement for primary tumor metastasis. Here, we demonstrated that small extracellular vesicles (sEV) carrying RAB21 homed to lung macrophages and interacted with integrin-β1 on macrophages. ABHD12 expression was high in lung metastatic tumors and was mostly expressed by macrophages. Head and neck squamous cell carcinoma (HNSCC)-derived sEVs carrying ABHD12-polarized macrophages toward an immunosuppressive phenotype, driving premetastatic niche formation, which facilitated lung metastasis. ABHD12 additionally upregulated S1PR1 by activating the AKT-FoxO1 pathway in macrophages, and significantly enhanced antitumor responses were observed in tumor models treated with agents targeting both S1PR1 and PD-1. Collectively, our study suggests that RAB21+ABHD12+ sEVs derived from HNSCC cells contribute to the formation of the immunosuppressive microenvironment in the premetastatic niche and are a potential therapeutic target for enhancing the antitumor efficacy of anti-PD-1 therapy.

Progress in the treatment of malignant ascites

Malignant ascites occurs as a symptom of the terminal stage of cancer, affecting the quality of life through abdominal distension, pain, nausea, anorexia, dyspnea and other symptoms. We describe the current main drug treatments in addition to surgery according to the traditional and new strategies. Traditional treatments were based on anti-tumor chemotherapy and traditional Chinese medicine treatments, as well as diuretics to relieve the patient's symptoms. New treatments mainly involve photothermal therapy, intestinal therapy and targeted immunity. This study emphasizes that both traditional and new therapies have certain advantages and disadvantages, and medication should be adjusted according to different periods of use and different patients. In conclusion, this article reviews the literature to systematically describe the primary treatment modalities for malignant ascites.

Role of microbiota in radiation-induced small-bowel damage

Radiation-induced gastrointestinal damage is a common acute radiation syndrome. Previous studies have highlighted that Galectin-1 and Interleukin-6 (IL-6) are associated with flaking of small intestinal villi and intestinal radioresistance. Therefore, our goal is to study whether gut bacteria regulated by galectin-1 or IL-6 can mitigate radiation-induced small intestine damage. In this study, differences between galectin-1, sgp130-regulated and wild-type (WT) mice were analyzed by microbiome array. The effects of the Firmicutes/Bacteroidetes (F/B) ratio and the proportion of bacterial distribution at the phylum level were observed after 18 Gy whole abdomen radiation. Fecal microbiota transplantation was used to implant radioresistant gut flora into WT mice, and the number of viable small intestinal crypt foci was observed by immunohistochemistry. Fecal transplantation from galectin-1 knockout and sgp130 transgenic mice, with higher radiation resistance, into WT mice significantly increased the number of surviving small intestinal crypts. This radiation resistance, generated through gene regulation, was not affected by the F/B ratio. We initially found that the small intestinal villi of WT mice receiving radioresistant mouse fecal bacteria demonstrated better repair outcomes after radiation exposure. These results indicate the need for a focus on the identification and application of superior radioresistant bacterial strains. In our laboratory, we will further investigate specific radioresistant bacterial strains to alleviate acute side effects of radiation therapy to improve the patients' immune ability and postoperative quality of life.

Tumor-Associated Macrophage Targeting of Nanomedicines in Cancer Therapy

The tumor microenvironment (TME) is pivotal in tumor growth and metastasis, aligning with the "Seed and Soil" theory. Within the TME, tumor-associated macrophages (TAMs) play a central role, profoundly influencing tumor progression. Strategies targeting TAMs have surfaced as potential therapeutic avenues, encompassing interventions to block TAM recruitment, eliminate TAMs, reprogram M2 TAMs, or bolster their phagocytic capabilities via specific pathways. Nanomaterials including inorganic materials, organic materials for small molecules and large molecules stand at the forefront, presenting significant opportunities for precise targeting and modulation of TAMs to enhance therapeutic efficacy in cancer treatment. This review provides an overview of the progress in designing nanoparticles for interacting with and influencing the TAMs as a significant strategy in cancer therapy. This comprehensive review presents the role of TAMs in the TME and various targeting strategies as a promising frontier in the ever-evolving field of cancer therapy. The current trends and challenges associated with TAM-based therapy in cancer are presented.

Severity of Peripheral Infection Differentially Affects Brain Functions in Mice via Microglia-Dependent and -Independent Mechanisms

Peripheral infection induces inflammation in peripheral tissues and the brain, impacting brain function. Glial cells are key players in this process. However, the effects of peripheral infection on glial activation and brain function remain unknown. Here, we showed that varying degrees of peripheral infection had different effects on the regulation of brain functions by microglia-dependent and -independent mechanisms. Acute mild infection (one-day LPS challenge: 1LPS) exacerbated middle cerebral artery occlusion (MCAO) injury, and severe infection (four-day LPS challenge: 4LPS) for one week suppressed it. MCAO injury was assessed by triphenyltetrazolium chloride staining. We observed early activation of microglia in the 1LPS and 4LPS groups. Depleting microglia with a colony-stimulating factor-1 receptor (CSF1R) antagonist had no effect on 1LPS-induced brain injury exacerbation but abolished 4LPS-induced protection, indicating microglial independence and dependence, respectively. Microglia-independent exacerbation caused by 1LPS involved peripheral immune cells including macrophages. RNA sequencing analysis of 4LPS-treated microglia revealed increased factors related to anti-inflammatory and neuronal tissue repair, suggesting their association with the protective effect. In conclusion, varying degrees of peripheral inflammation had contradictory effects (exacerbation vs. protection) on MCAO, which may be attributed to microglial dependence. Our findings highlight the significant impact of peripheral infection on brain function, particularly in relation to glial cells.

Depletion of muscularis macrophages ameliorates inflammation-driven dysmotility in murine colitis model

Previously, the presence of a blood-myenteric plexus barrier and its disruption was reported in experimentally induced colitis via a macrophage-dependent process. The aim of this study is to reveal how myenteric barrier disruption and subsequent neuronal injury affects gut motility in vivo in a murine colitis model. We induced colitis with dextran sulfate sodium (DSS), with the co-administration of liposome-encapsulated clodronate (L-clodronate) to simultaneously deplete blood monocytes contributing to macrophage infiltration in the inflamed muscularis of experimental mice. DSS-treated animals receiving concurrent L-clodronate injection showed significantly decreased blood monocyte numbers and colon muscularis macrophage (MM) density compared to DSS-treated control (DSS-vehicle). DSS-clodronate-treated mice exhibited significantly slower whole gut transit time than DSS-vehicle-treated animals and comparable to that of controls. Experiments with oral gavage-fed Evans-blue dye showed similar whole gut transit times in DSS-clodronate-treated mice as in control animals. Furthermore, qPCR-analysis and immunofluorescence on colon muscularis samples revealed that factors associated with neuroinflammation and neurodegeneration, including Bax1, Hdac4, IL-18, Casp8 and Hif1a are overexpressed after DSS-treatment, but not in the case of concurrent L-clodronate administration. Our findings highlight that MM-infiltration in the muscularis layer is responsible for colitis-associated dysmotility and enteric neuronal dysfunction along with the release of mediators associated with neurodegeneration in a murine experimental model.

Enhancement of efferocytosis through biased FPR2 signaling attenuates intestinal inflammation

Efficient clearance of dying cells (efferocytosis) is an evolutionarily conserved process for tissue homeostasis. Genetic enhancement of efferocytosis exhibits therapeutic potential for inflammation resolution and tissue repair. However, pharmacological approaches to enhance efferocytosis remain sparse due to a lack of targets for modulation. Here, we report the identification of columbamine (COL) which enhances macrophage-mediated efferocytosis and attenuates intestinal inflammation in a murine colitis model. COL enhances efferocytosis by promoting LC3-associated phagocytosis (LAP), a non-canonical form of autophagy. Transcriptome analysis and pharmacological characterization revealed that COL is a biased agonist that occupies a part of the ligand binding pocket of formyl peptide receptor 2 (FPR2), a G-protein coupled receptor involved in inflammation regulation. Genetic ablation of the Fpr2 gene or treatment with an FPR2 antagonist abolishes COL-induced efferocytosis, anti-colitis activity and LAP. Taken together, our study identifies FPR2 as a potential target for modulating LC3-associated efferocytosis to alleviate intestinal inflammation and highlights the therapeutic value of COL, a natural and biased agonist of FPR2, in the treatment of inflammatory bowel disease.

ATP ion channel P2X7 receptor as a regulatory molecule in the progression of colorectal cancer

Large amounts of adenosine triphosphate (ATP), a natural P2X7 receptor activator, are released during colorectal carcinogenesis. P2X7 receptor activation regulates the activity of colorectal cancer (CRC) cells by mediating intracellular signal transduction. Importantly, the opening and activation of membrane pores of P2X7 receptor are different, which can play a dual role in promoting or inhibiting the progression of CRC. These can also depend on P2X7 receptor to regulate the activities of immune cells in the microenvironment, play the functions of immune regulation, immune escape and immune monitoring. While the use of P2X7 receptor antagonists (such as BBG, A438079 and A740003) can play a certain inhibitory pharmacological role on the activity of CRC. Therefore, in this paper, the mechanism and immunomodulatory function of P2X7 receptor involved in the progression of CRC were discussed. Moreover, we discussed the effect of antagonizing the activity of P2X7 receptor on the progression of CRC. So P2X7 receptor may be a new pharmacological molecular target for the treatment of CRC.

Gut microbiota and tumor-associated macrophages: potential in tumor diagnosis and treatment

Avoiding immune destruction and polymorphic microbiomes are two key hallmarks of cancer. The tumor microenvironment (TME) is essential for the development of solid tumors, and the function of tumor-associated macrophages (TAMs) in the TME is closely linked to tumor prognosis. Therefore, research on TAMs could improve the progression and control of certain tumor patients. Additionally, the intestinal flora plays a crucial role in metabolizing substances and maintaining a symbiotic relationship with the host through a complex network of interactions. Recent experimental and clinical studies have suggested a potential link between gut microbiome and TME, particularly in regulating TAMs. Understanding this association could improve the efficacy of tumor immunotherapy. This review highlights the regulatory role of intestinal flora on TAMs, with a focus on gut microbiota and their metabolites. The implications of this association for tumor diagnosis and treatment are also discussed, providing a promising avenue for future clinical treatment strategies.

Crosstalk between gut microbiota and gut resident macrophages in inflammatory bowel disease

Macrophages residing in the gut maintain gut homeostasis by orchestrating patho-gens and innocuous antigens. A disturbance in macrophages leads to gut inflamma-tion, causing conditions such as inflammatory bowel disease (IBD). Macrophages ex-hibit remarkable plasticity, as they are sensitive to various signals in the tissue micro-environment. During the recent decades, gut microbiota has been highlighted refer-ring to their critical roles in immunity response. Microbiome-derived metabolites and products can interact with macrophages to participate in the progression of IBD. In this review, we describe recent findings in this field and provide an overview of the current understanding of microbiota-macrophages interactions in IBD, which may lead to the development of new targets and treatment options for patients with IBD.

Application of exosomal miRNA mediated macrophage polarization in colorectal cancer: Current progress and challenges

Colorectal cancer (CRC) is a major global health problem with high morbidity and mortality rates. Surgical resection is the main treatment for early-stage CRC, but detecting it early is challenging. Therefore, effective therapeutic targets for advanced patients are still lacking. Exosomes, tiny vesicles in body fluids, play a crucial role in tumor metastasis, immune regulation, and drug resistance. Interestingly, they can even serve as a biomarker for cancer diagnosis and prognosis. Studies have shown that exosomes can carry miRNA, mediate the polarization of M1/M2 macrophages, promote the proliferation and metastasis of cancer cells, and affect the prognosis of CRC. Since the gastrointestinal tract has many macrophages, understanding the mechanism behind exosomal miRNA-mediated macrophage polarization in CRC treatment is crucial. This article summarizes recent advancements in the study of exosomal miRNAs in CRC and their potential as diagnostic and prognostic markers.

Gemcitabine-loaded synthetic high-density lipoprotein preferentially eradicates hepatic monocyte-derived macrophages in mouse liver with colorectal cancer metastases

Liver metastasis of colorectal cancer (CRC) is the critical cause of CRC-related death due to its unique immunosuppressive microenvironment. In this study we generated a gemcitabine-loaded synthetic high-density lipoprotein (G-sHDL) to reverse immunosuppression in livers with CRC metastases. After intravenous injection, sHDL targeted hepatic monocyte-derived alternatively activated macrophages (Mono-M2) in the livers of mice bearing both subcutaneous tumors and liver metastases. The G-sHDL preferentially eradicated Mono-M2 in the livers with CRC metastases, which consequently prevented Mono-M2-mediated killing of tumor antigen-specific CD8+ T cells in the livers and thus improved the densities of tumor antigen-specific CD8+ T cells in the blood, tumor-draining lymph nodes and subcutaneous tumors of the treated mice. While reversing the immunosuppressive microenvironment, G-sHDL also induced immunogenic cell death of cancer cells, promoted maturation of dendritic cells, and increased tumor infiltration and activity of CD8+ T cells. Collectively, G-sHDL inhibited the growth of both subcutaneous tumors and liver metastases, and prolonged the survival of animals, which could be further improved when used in conjunction with anti-PD-L1 antibody. This platform can be a generalizable platform to modulate immune microenvironment of diseased livers.

Identifying Macrophage-Related Genes in Ulcerative Colitis Using Weighted Coexpression Network Analysis and Machine Learning

Ulcerative colitis (UC) is an inflammatory bowel disease of unknown cause that typically affects the colon and rectum. Innate intestinal immunity, including macrophages, plays a significant role in the pathological development of UC. Using the CIBERSORT algorithm, we observed elevated levels of 22 types of immune cell infiltrates, as well as increased M1 and decreased M2 macrophages in UC compared to normal colonic mucosa. Weighted gene coexpression network analysis (WGCNA) was used to identify modules associated with macrophages and UC, resulting in the identification of 52 macrophage-related genes (MRGs) that were enriched in macrophages at single-cell resolution. Consensus clustering based on these 52 MRGs divided the integrated UC cohorts into three subtypes. Machine learning algorithms were used to identify ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1), sodium- and chloride-dependent neutral and basic amino acid transporter B(0+) (SLC6A14), and 3-hydroxy-3-methylglutaryl-CoA synthase 2 (HMGCS2) in the training set, and their diagnostic value was validated in independent validation sets. Gene set enrichment analysis (GSEA) and gene set variation analysis (GSVA) revealed the main biological effects, and that interleukin-17 was one of several signaling pathways enriched by the three genes. We also constructed a competitive endogenous RNA (CeRNA) network reflecting a potential posttranscriptional regulatory mechanism. Expression of diagnostic markers was validated in vivo and in biospecimens, and our immunohistochemistry (IHC) results confirmed that HMGCS2 gradually decreased during the transformation of UC to colorectal cancer. In conclusion, ENPP1, SLC6A14, and HMGCS2 are associated with macrophages and the progression of UC pathogenesis and have good diagnostic value for patients with UC.

The microRNA-4766/VEGFA axis mediates macrophage M2-type polarization to inhibit colorectal cancer proliferation and migration

OBJECTIVE

To investigate the miR-4766/VEGFA axis in regulating M2-type macrophage polarization under hypoxia and its effect on the proliferation and migration of colorectal cancer (CRC) cells.

METHODS

The differentially expressed genes (DEGs) in macrophages before and after hypoxia treatment in the dataset GSE154427 were analyzed. microRNA (miR)-4766 and VEGFA were selected as the research objects and then detected for mRNA expression and protein level using qRT-PCR and Western blot, respectively. The expression levels of M2 macrophage markers such as CD206, CD163, and ARG1 were detected to determine the M2-type macrophage polarization. The targeted binding of miR-4766 to VEGFA was verified using Dual-luciferase reporter gene assay. CCK-8 and Transwell assays were performed, respectively, to detect the capacity of cells to proliferate and migrate. IL-10 and TGF-β levels in the conditioned medium were detected using ELISA.

RESULTS

miR-4766 was upregulated, and VEGFA was downregulated in hypoxia-treated macrophages. miR-4766 inhibited, while VEGFA promoted the polarization of M2-type macrophages. miR-4766 targeted and negatively regulated VEGFA. miR-4766 inhibited the polarization of M2-type macrophages and then suppressed CRC cell proliferation and migration via targeting VEGFA.

CONCLUSION

Restoring miR-4766 expression to inhibit VEGFA expression promised to be a potential strategy to suppress CRC development.

Panaxynol alleviates colorectal cancer in a murine model via suppressing macrophages and inflammation

Currently available colorectal cancer (CRC) therapies have limited efficacy and severe adverse effects that may be overcome with the alternative use of natural compounds. We previously reported that panaxynol (PA), a bioactive component in American ginseng, possesses anticancer properties in vitro and suppresses murine colitis through its proapoptotic and anti-inflammatory properties. Because colitis is a predisposing factor of CRC and inflammation is a major driver of CRC, we sought to evaluate the therapeutic potential of PA in CRC. Azoxymethane-dextran sodium sulfate (AOM/DSS) mice (C57BL/6) were administered 2.5 mg/kg PA or vehicle 3 times/wk via oral gavage over 12 wk. PA improved clinical symptoms (P ≤ 0.05) and reduced tumorigenesis (P ≤ 0.05). This improvement may be reflective of PA's restorative effect on intestinal barrier function; PA upregulated the expression of essential tight junction and mucin genes (P ≤ 0.05) and increased the abundance of mucin-producing goblet cells (P ≤ 0.05). Given that macrophages play a substantial role in the pathogenesis of CRC and that we previously demonstrated that PA targets macrophages in colitis, we next assessed macrophages. We show that PA reduces the relative abundance of colonic macrophages within the lamina propria (P ≤ 0.05), and this was consistent with a reduction in the expression of important markers of macrophages and inflammation (P ≤ 0.05). We further confirmed PA's inhibitory effects on macrophages in vitro under CRC conditions (P ≤ 0.05). These results suggest that PA is a promising therapeutic compound to treat CRC and improve clinical symptoms given its ability to inhibit macrophages and modulate the inflammatory environment in the colon.NEW & NOTEWORTHY We report that panaxynol (PA) reduces colorectal cancer (CRC) by improving the colonic and tumor environment. Specifically, we demonstrate that PA improves crypt morphology, upregulates crucial tight junction and mucin genes, and promotes the abundance of mucin-producing goblet cells. Furthermore, PA reduces macrophages and associated inflammation, important drivers of CRC, in the colonic environment. This present study provides novel insights into the potential of PA as a therapeutic agent to ameliorate CRC tumorigenesis.

Macrophages depletion alleviates lung injury by modulating AKT3/GXP4 following ventilator associated pneumonia

Background

AKT3 appears to play a role in lung cancer. However, its role in ventilator-associated pneumonia is still unclear. Therefore, this study aimed to investigate the role of AKT3 in macrophages during ventilator-associated pneumonia.

Methods

The mRNA level of AKT3, Data from The Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO), The data is analyzed using the Xiantao academic analysis tool. Additionally, the roles of AKT3 in ventilator-associated pneumonia (VAP) were investigated through in vivo experiments.

Results

AKT3 was differentially expressed in various normal and tumor tissues. Functional enrichment analysis indicated the immunomodulatory function and inflammatory response of AKT3 in lung cancer. Depletion of macrophages protected against lung epithelial cells and significantly decreased MMP9, MMP19, FTH, and FTL expression levels and increased GPX4 expression levels, while partially reversing the changes in macrophage. Mechanistically, macrophage depletion attenuates ferroptosis of lung epithelial cells by modulating AKT3 following VAP.

Conclusion

Collectively, this study suggests the need for further validation of the immunoregulatory function of AKT3 in lung cancer. Additionally, macrophage depletion mitigates lung injury by modulating the AKT3/GPX4 pathway in the context of VAP.

Orosomucoid 1 promotes colorectal cancer progression and liver metastasis by affecting PI3K/AKT pathway and inducing macrophage M2 polarization

Approximately 25-30% of those affected by colorectal cancer (CRC), the most prevalent gastrointestinal malignancy, develop metastases. The survival rate of patients with liver metastasis of CRC (CRLM) remains low owing to its unpredictability and a lack of biomarkers that can be applied to distinguish groups at higher risk for CRLM among patients with CRC. Therefore, our study aimed to find biomarkers that can predict the risk of CRLM. Screening of the Gene Expression Omnibus database, supported by an analysis of clinically obtained tissue and serum data using qPCR and ELISA, in an attempt to identify relevant biomarkers, enabled us to determine that orosomucoid 1 (ORM1) was differentially expressed in liver metastases and primary tumors of patients with CRC. Functionally, overexpression of ORM1 promoted the epithelial-mesenchymal transition and the proliferative, migratory, and invasive activities of MC38 cells and activated the PI3K/AKT signaling pathway. Moreover, MC38 cells overexpressing ORM1 enhanced the tumor immune microenvironment by promoting macrophage M2 polarization and elevating interleukin-10 (IL-10) expression. In vivo experiments further confirmed in vitro results, indicating that liver metastases elevated by ORM1 were partially attenuated by the depletion of macrophages or IL-10. Considered together, ORM1 promotes CRC progression and liver metastasis by regulating tumor cell growth and inducing macrophage M2 polarization, which mediates tumor immune tolerance, and thus acts as a potential predictive marker and therapeutic target in CRLM.

Macrophage-Based Therapeutic Strategies in Hematologic Malignancies

Macrophages are types of immune cells, with ambivalent functions in tumor growth, which depend on the specific environment in which they reside. Tumor-associated macrophages (TAMs) are a diverse population of immunosuppressive myeloid cells that play significant roles in several malignancies. TAM infiltration in malignancies has been linked to a poor prognosis and limited response to treatments, including those using checkpoint inhibitors. Understanding the precise mechanisms through which macrophages contribute to tumor growth is an active area of research as targeting these cells may offer potential therapeutic approaches for cancer treatment. Numerous investigations have focused on anti-TAM-based methods that try to eliminate, rewire, or target the functional mediators released by these cells. Considering the importance of these strategies in the reversion of tumor resistance to conventional therapies and immune modulatory vaccination could be an appealing approach for the immunosuppressive targeting of myeloid cells in the tumor microenvironment (TME). The combination of reprogramming and TAM depletion is a special feature of this approach compared to other clinical strategies. Thus, the present review aims to comprehensively overview the pleiotropic activities of TAMs and their involvement in various stages of cancer development as a potent drug target, with a focus on hematologic tumors.

Probiotics formulation and cancer nanovaccines show synergistic effect in immunotherapy and prevention of colon cancer

Probiotics play essential roles in immune modulation. Combining probiotics with cancer vaccines potentially can achieve a synergistic effect. To maximize the efficacy of probiotics, proper probiotics formulation is necessary. Herein, Lactobacillus rhamnosus and Bifidobacterium longum are coated with lipid membrane to achieve the goal of losing less activity and bettering colonization in colon. In the subcutaneous transplanted colon cancer mouse model, probiotics formulation showed potent preventive and therapeutic efficacy, and the efficacy could be further improved by combining with cancer nanovaccines. Probiotics formulation can perform as immune adjuvants to enhance the innate immune response or as in-situ cancer vaccines. In the study of preventing chemical-induced orthotopic colon cancer model, probiotics formulation alone efficiently reduced tumor number in colon and the efficacy is improved by combining with cancer nanovaccines. All in all, the studies demonstrated that probiotics formulation can assist to maximize the efficacy of cancer nanovaccines.

Physical exercise, health, and disease treatment: The role of macrophages

Subclinical inflammation is linked to comorbidities and risk factors, consolidating the diagnosis of chronic non-communicable diseases, such as insulin resistance, atherosclerosis, hepatic steatosis, and some types of cancer. In this context, the role of macrophages is highlighted as a marker of inflammation as well as for the high power of plasticity of these cells. Macrophages can be activated in a wide range between classical or proinflammatory, named M1, and alternative or anti-inflammatory, also known as M2 polarization. All nuances between M1 and M2 macrophages orchestrate the immune response by secreting different sets of chemokines, while M1 cells promote Th1 response, the M2 macrophages recruit Th2 and Tregs lymphocytes. In turn, physical exercise has been a faithful tool in combating the proinflammatory phenotype of macrophages. This review proposes to investigate the cellular and molecular mechanisms in which physical exercise can help control inflammation and infiltration of macrophages within the non-communicable diseases scope. During obesity progress, proinflammatory macrophages predominate in adipose tissue inflammation, which reduces insulin sensitivity until the development of type 2 diabetes, progression of atherosclerosis, and diagnosis of non-alcoholic fatty liver disease. In this case, physical activity restores the balance between the proinflammatory/anti-inflammatory macrophage ratio, reducing the level of meta-inflammation. In the case of cancer, the tumor microenvironment is compatible with a high level of hypoxia, which contributes to the advancement of the disease. However, exercise increases the level of oxygen supply, favoring macrophage polarization in favor of disease regression.

F4/80+Ly6Chigh Macrophages Lead to Cell Plasticity and Cancer Initiation in Colitis

BACKGROUND & AIMS

Colorectal cancer is a leading cause of cancer death, and a major risk factor is chronic inflammation. Despite the link between colitis and cancer, the mechanism by which inflammation leads to colorectal cancer is not well understood.

METHODS

To investigate whether different forms of inflammation pose the same risk of cancer, we compared several murine models of colitis (dextran sodium sulfate [DSS], 2,4,6-trinitrobenzene sulfonic acid, 4-ethoxylmethylene-2-phenyloxazol-5-one, Citrobacter rodentium, Fusobacterium nucleatum, and doxorubicin) with respect to their ability to lead to colonic tumorigenesis. We attempted to correlate the severity of colitis and inflammatory profile with the risk of tumorigenesis in both azoxymethane-dependent and Dclk1/APCfl/fl murine models of colitis-associated cancer.

RESULTS

DSS colitis reproducibly led to colonic tumors in both mouse models of colitis-associated cancer. In contrast, all other forms of colitis did not lead to cancer. When compared with the colitis not associated with tumorigenesis, DSS colitis was characterized by significantly increased CD11b+F4/80+Ly6Chigh macrophages and CD11b+Ly6G+ neutrophils. Interestingly, depletion of the CD11b+F4/80+Ly6Chigh macrophages inhibited tumorigenesis, whereas depletion of CD11b+Ly6G+ neutrophils had no effect on tumorigenesis. Furthermore, the macrophage-derived cytokines interleukin-1β, tumor necrosis factor-α, and interleukin-6 were significantly increased in DSS colitis and promoted stemness of Dclk1+ tuft cells that serve as the cellular origin of cancer.

CONCLUSIONS

We have identified CD11b+F4/80+Ly6Chigh macrophages as key mediators of cancer initiation in colitis-associated cancer. Development of new therapies that target these cells may provide an effective preventative strategy for colitis-associated cancer.

AC1Q3QWB inhibits colorectal cancer progression by modulating the immune response and balancing the structure of the intestinal microbiota

AC1Q3QWB enhances CD8 + T cell response and triggers accumulation of Tregs and B cells.

BACKGROUND

Colorectal cancer (CRC) is a common malignancy with high mortality and few effective therapeutic measures. Gut microbiota dysbiosis and chronic inflammation might contribute to the development of CRC. The present study aimed to explore the effect of AC1Q3QWB (AQB) on colon carcinogenesis in vivo.

METHODS

A mouse colon cancer model was constructed by intraperitoneal injection of 10 mg/kg of Azoxymethane (AOM) and 2 % dextran sodium sulfate (DSS) in drinking water. Mice were randomly assigned to four groups: normal control (NC), AOM/DSS (model control, MC), DMSO + AOM/DSS (DMSO), and AQB + AOM/DSS (AQB). Mice in the AQB group were treated with an intraperitoneal injection of AQB (50 mg/kg) after successful modeling. Then, the disease activity index (DAI) of colitis was analyzed. Colon tissues were collected for hematoxylin-eosin, immunohistochemistry, and microscopic and histological evaluation. Stool samples were collected for microbiota analysis by 16S rRNA sequencing. Blood samples were analyzed by flow cytometry to investigate the inflammatory response.

RESULTS

In AOM/DSS-induced CRC mouse model, AQB treatment dramatically reduced the number and size of colon tumors. AQB treatment enhances CD8+⁺T cell response and triggers the accumulation of CD4+⁺CD25+⁺Foxp3+⁺Regulatory T cells (Tregs) and B cells. AQB regulated the structure and composition of the gut microbiota, which decreased the Firmicutes/Bacteroidetes ratio at the phylum level and increased the abundance of probiotics.

CONCLUSIONS

AQB has potent antitumor activity against colorectal cancer in vivo by a mechanism that might involve modulation of the immune system and alteration of the intestinal microbiota.

An empirical review on the resistance mechanisms of epidermal growth factor receptor inhibitors and predictive molecular biomarkers in colorectal cancer

Despite advances in cytotoxic treatments, colorectal cancer remains a leading cause of death. Metastatic colorectal cancer (mCRC) patients have a poor prognosis despite improved treatments and more prolonged median survival. Monoclonal antibodies like cetuximab and panitumumab target the epidermal growth factor receptor (EGFR). They play an essential role in the treatment of metastatic colorectal cancer (mCRC) due to their efficacy in multiple phase III clinical trials across multiple treatment lines. It was discovered that anti-EGFR moAbs were only effective for a small number of patients. Mutations in KRAS and NRAS have been identified as biomarkers of drug resistance. New molecular predictors and prognostic markers are used clinically. The K-Ras mutation is the first molecular marker of a lack of response to EGFR-targeted therapy in K-Ras-mutant patients. Validating predictive and prognostic markers will improve cancer treatments. This article examines molecular markers that can predict colorectal cancer prognosis.

The interaction between innate immunity and oral microbiota in oral diseases

INTRODUCTION

Innate immunity serves as the frontline to combat invading pathogens. Oral microbiota is the total collection of microorganisms colonized within the oral cavity. By recognizing the resident microorganisms through pattern recognition receptors, innate immunity is capable of interacting with oral microbiota and maintaining homeostasis. Dysregulation of interaction may lead to the pathogenesis of several oral diseases. Decoding the crosstalk between oral microbiota and innate immunity may be contributory to developing novel therapies for preventing and treating oral diseases.

AREAS COVERED

This article reviewed pattern recognition receptors in the recognition of oral microbiota, the reciprocal interaction between innate immunity and oral microbiota, and discussed how the dysregulation of this relationship leads to the pathogenesis and development of oral diseases.

EXPERT OPINION

Many studies have been conducted to illustrate the relationship between oral microbiota and innate immunity and its role in the occurrence of different oral diseases. The impact and mechanisms of innate immune cells on oral microbiota and the mechanisms of dysbiotic microbiota in altering innate immunity are still needed to be investigated. Altering the oral microbiota might be a possible solution for treating and preventing oral diseases.

Human Keratinocyte-Derived Exosomal MALAT1 Promotes Diabetic Wound Healing by Upregulating MFGE8 via microRNA-1914-3p

Purpose

Diabetic wound is a highly prevalent and refractory disease. Extensive studies have confirmed that keratinocytes and macrophages play an important role in the process of wound healing. Additionally, exosomes are regarded as a vital intercellular communication tool. This study aimed to investigate the role of human keratinocyte-derived exosomal MALAT1 in the treatment of diabetic wound by influencing the biological function of macrophages.

Methods

We mainly assessed the function of MALAT1 on the biological changes of macrophages, and the expression of MALAT1 in the keratinocyte-exosomes analyzed by quantitative real-time polymerase chain reaction (RT-qPCR). The downstream interaction between RNAs or proteins was assessed by mechanistic experiments. Besides, we evaluated the effects of human keratinocyte-derived exosomal MALAT1 on diabetic wound healing in vivo to verify in vitro results.

Results

We demonstrated that human keratinocyte-derived exosomal MALAT1 enhanced the biological functions of high glucose-injured macrophages, including phagocytosis, converting to a pro-healing phenotype and reducing apoptosis. Mechanistically, MALAT1 accelerated the expression of MFGE8 by competitively binding to miR-1914-3p, thereby affecting the function of macrophages and the signal axis of TGFB1/SMAD3, and finally promoting the healing of diabetic wounds. Human keratinocyte-derived exosomal MALAT1 might promote collagen deposition, ECM remodeling, and expression of MFGE8, VEGF, and CD31 but reduce the expression of TGFB and SMAD3 in an in vivo model of diabetic mice wounds, which accelerated diabetic wound healing and restored its function.

Conclusion

The current study revealed that human keratinocyte-derived exosomal MALAT1 would suppress miR-1914-3p to activate MFGE8 and eventually promote wound healing by enhancing macrophage phagocytosis, converting to a pro-healing phenotype and reducing apoptosis. It proposed that keratinocyte-derived exosomes might have the capacity to serve as a new method for the clinical treatment of diabetic wound.

The Influence of the microbiome on the innate immune microenvironment of solid tumors

Cancer remains a leading cause of death despite many advances in medical and surgical therapy. In recent decades, the investigation for novel therapeutic strategies with greater efficacy and reduced side effects has led to a deeper understanding of the relationship between the microbiome and the immune system in the context of cancer. The ability of the immune system to detect and kill cancer is now recognized to be greatly influenced by the microbial ecosystem of the host. While most of these studies, as well as currently used immunotherapeutics, focus on the adaptive immune system, this minimizes the impact of the innate immune system in cancer surveillance and its regulation by the host microbiome. In this review, known influences of the microbiome on the innate immune cells in the tumor microenvironment will be discussed in the context of individual innate immune cells. Current and needed areas of investigation will highlight the field and its potential impact in the clinical treatment of solid malignancies.

Interleukin-34 deficiency aggravates development of colitis and colitis-associated cancer in mice

BACKGROUND

Although expression of interleukin (IL)-34 is upregulated in active ulcerative colitis (UC), the molecular function and underlying mechanism are largely unclear.

AIM

To investigate the function of IL-34 in acute colitis, in a wound healing model and in colitis-associated cancer in IL-34-deficient mice.

METHODS

Colitis was induced by administration of dextran sodium sulfate (DSS), and carcinogenesis was induced by azoxymethane (AOM). Whether the impact of IL-34 on colitis was dependent on macrophages was validated by depletion of macrophages in a murine model. The association between IL-34 expression and epithelial proliferation was studied in patients with active UC.

RESULTS

IL-34 deficiency aggravated murine colitis in acute colitis and in wound healing phase. The effect of IL-34 on experimental colitis was not dependent on macrophage differentiation and polarization. IL-34-deficient mice developed more tumors than wild-type mice following administration of AOM and DSS. No significant difference was shown in degree of cellular differentiation in tumors between wild-type and IL-34-deficient mice. IL-34 was dramatically increased in the active UC patients as previously reported. More importantly, expression of IL-34 was positively correlated with epithelial cell proliferation in patients with UC.

CONCLUSION

IL-34 deficiency exacerbates colonic inflammation and accelerates colitis-associated carcinogenesis in mice. It might be served as a potential therapeutic target in UC.

Caerin 1.1/1.9 Enhances Antitumour Immunity by Activating the IFN-α Response Signalling Pathway of Tumour Macrophages

Macrophages are one of the essential components of the tumour microenvironment (TME) of many cancers and show complex heterogeneity and functions. More recent research has been focusing on the characterisation of tumour-associated macrophages (TAMs). Previously, our study demonstrated that caerin 1.1/1.9 peptides significantly improve the therapeutic efficacy of combined specific immunotherapy and immune checkpoint blockade in a murine transplantable tumour model (TC-1). In this study, the mice inoculated with TC-1 tumour were immunised differently. The TAMs were isolated using flow cytometry and characterised by cytokine ELISA. The survival rates of mice with different treatments containing caerin 1.1/19 were assessed comparatively, including those with/without macrophage depletion. The single-cell RNA sequencing (scRNA-seq) data of previous studies were integrated to further reveal the functions of TAMs with the treatments containing caerin 1.1/1.9. As a comparison, the TAMs of stage I and II cervical cancer patients were analysed using scRNA-seq analysis. We demonstrate that caerin induced tumour clearance is associated with infiltration of tumours by IL-12 secreting Ly6C+F4/80+ macrophages exhibiting enhanced IFN-α response signalling, renders animals resistant to further tumour challenge, which is lost after macrophage depletion. Our results indicate that caerin 1.1/1.9 treatment has great potential in improving current immunotherapy efficacy.

The HIF-prolyl hydroxylases have distinct and nonredundant roles in colitis-associated cancer

Colitis-associated colorectal cancer (CAC) is a severe complication of inflammatory bowel disease (IBD). HIF-prolyl hydroxylases (PHD1, PHD2, and PHD3) control cellular adaptation to hypoxia and are considered promising therapeutic targets in IBD. However, their relevance in the pathogenesis of CAC remains elusive. We induced CAC in Phd1-/-, Phd2+/-, Phd3-/-, and WT mice with azoxymethane (AOM) and dextran sodium sulfate (DSS). Phd1-/- mice were protected against chronic colitis and displayed diminished CAC growth compared with WT mice. In Phd3-/- mice, colitis activity and CAC growth remained unaltered. In Phd2+/- mice, colitis activity was unaffected, but CAC growth was aggravated. Mechanistically, Phd2 deficiency (i) increased the number of tumor-associated macrophages in AOM/DSS-induced tumors, (ii) promoted the expression of EGFR ligand epiregulin in macrophages, and (iii) augmented the signal transducer and activator of transcription 3 and extracellular signal-regulated kinase 1/2 signaling, which at least in part contributed to aggravated tumor cell proliferation in colitis-associated tumors. Consistently, Phd2 deficiency in hematopoietic (Vav:Cre-Phd2fl/fl) but not in intestinal epithelial cells (Villin:Cre-Phd2fl/fl) increased CAC growth. In conclusion, the 3 different PHD isoenzymes have distinct and nonredundant effects, promoting (PHD1), diminishing (PHD2), or neutral (PHD3), on CAC growth.

Gastric cancer-derived exosomal miR-519a-3p promotes liver metastasis by inducing intrahepatic M2-like macrophage-mediated angiogenesis

Background

Liver metastasis (LM) is a major obstacle to the prognosis of gastric cancer (GC) patients, but the molecular mechanism underlying gastric cancer liver metastasis (GC-LM) remains unknown. Exosomes have been identified as an important mediator of communication between tumor cells and the microenvironment. Therefore, we sought to investigate the effects of primary GC cells on the liver microenvironment and the role of exosomal microRNAs (exo-miRNA) in GC-LM.

Methods

Sequential differential centrifugation, transmission electron microscopy and NanoSight analysis were used to extract and characterize exosomes. MicroRNA sequencing in GC-derived exosomes and mRNA sequencing in PMA-treated THP-1 cells were used to identify differentially expressed miRNAs in exosomes and the functional targets of exosomal miR-519a-3p (exo-miR-519a-3p) in macrophages, respectively. Tracing and internalization of exosomes and transfer of exo-miR-519a-3p were observed by immunofluorescence. Tubule formation assays, aortic ring assays, and exosome-educated GC-LM model were used to investigate the roles of GC-derived exosomes and exo-miR-519a-3p in angiogenesis and GC-LM. Luciferase reporter assay, qRT-PCR, Western blot, ELISA, flow cytometry and immunofluorescence were used to investigate the regulatory mechanism of exo-miR-519a-3p at GC-LM.

Results

The expression level of miR-519a-3p in serum exosomes was significantly higher in GC-LM patients than in patients without LM, and high expression of exo-miR-519a-3p indicates a worse prognosis. GC-derived exosomes are mainly accumulated in the liver and internalized by intrahepatic macrophages. Mechanistically, exo-miR-519a-3p activates the MAPK/ERK pathway by targeting DUSP2, thereby causing M2-like polarization of macrophages. M2-like polarized macrophages accelerate GC-LM by inducing angiogenesis and promoting intrahepatic premetastatic niche formation.

Conclusions

Our results indicate that exo-miR-519a-3p plays a critical role in mediating crosstalk between primary GC cells and intrahepatic macrophages and is a potential therapeutic target for GC-LM.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-022-02499-8.

Congenital adiponectin deficiency mitigates high-fat-diet-induced obesity in gonadally intact male and female, but not in ovariectomized mice

Epidemiological literature indicates that women are less susceptible to type II diabetes (T2D) than males. The general consensus is that estrogen is protective, whereas its deficiency in post-menopause is associated with adiposity and impaired insulin sensitivity. However, epidemiological data suggests that males are more prone to developing T2D, and at a lower BMI, compared to females during post-menopausal years; suggesting that another factor, other than estrogen, protects females. We proposed to determine if adiponectin (APN) serves as this protective factor. An initial experiment was performed in which gonadally intact male and female mice were fed either a purified low-fat diet (LFD) or high-fat diet (HFD) (40% kcals from fat) for 16 weeks. An additional group of HFD ovariectomy (OVX) mice were included to assess estrogen deficiency’s impact on obesity. Body composition, adipose tissue inflammation, ectopic lipid accumulation as well as glucose metabolism and insulin resistance were assessed. In corroboration with previous data, estrogen deficiency (OVX) exacerbated HFD-induced obesity in female mice. However, despite a higher body fat percentage and a similar degree of hepatic and skeletal muscle lipid accumulation, female OVX HFD-fed mice exhibited enhanced insulin sensitivity relative to HFD-fed males. Therefore, a subsequent HFD experiment was performed utilizing male and female (both gonadally intact and OVX) APN deficient mice (APN^−/−) and wildtype littermates to determine if APN is the factor which protects OVX females from the similar degree of metabolic dysfunction as males in the setting of obesity. Indirect calorimetry was used to determine observed phenotype differences. APN deficiency limited adiposity and mitigated HFD-induced insulin resistance and adipose tissue inflammation in gonadally intact male and female, but not in OVX mice. Using indirect calorimetry, we uncovered that slight, but non-statistically significant differences in food intake and energy expenditure leading to a net difference in energy balance likely explain the reduced body weight exhibited by male APN-deficient mice. In conclusion, congenital APN deficiency is protective against obesity development in gonadally intact mice, however, in the setting of estrogen deficiency (OVX) this is not true. These findings suggest that gonadal status dictates the protective effects of congenital APN deficiency in the setting of HFD-induced obesity.

TMP195 Exerts Antitumor Effects on Colorectal Cancer by Promoting M1 Macrophages Polarization

Studies have shown that epigenetic enzymes such as histone deacetylase (HDAC) are closely related to cancers and that several HDAC inhibitors exert antitumor effects. Studies have further suggested that class IIa HDAC inhibitors are related to immune functions, including immune responses and the expression of chemokines and complement pathway components. TMP195, a selective class IIa HDAC inhibitor, has been reported to be effective against breast cancer. However, the role and mechanism of TMP195 in colorectal cancer remain unknown. In this study, we found that TMP195 significantly reduced the tumor burden in two mouse models of colitis-associated colorectal cancer (CAC) and subcutaneous tumor. Mechanistically, TMP195 decreased the proportion of total macrophages but increased the proportion of M1 macrophages by promoting polarization, resulting in the increased release of inflammatory cytokines. TMP195 had no direct effect on the proliferation of colorectal cancer cells, and its antitumor effect on the colorectal cancer disappeared when macrophages were partly depleted by clodronate liposomes. In addition, TMP195 enhanced the efficacy of PD-1 blockade. The present study revealed that the combination of TMP195 and PD-1 blockade may provide a therapeutic strategy for colorectal cancer.

Pou3f1 mediates the effect of Nfatc3 on ulcerative colitis-associated colorectal cancer by regulating inflammation

Background

Ulcerative colitis-associated colorectal cancer (UC-CRC) is an important complication of ulcerative colitis. Pou3f1 (POU class 3 homeobox 1) is a critical regulator for developmental events and cellular biological processes. However, the role of Pou3f1 in the development of UC-CRC is unclear.

Methods

In vivo, a UC-CRC mouse model was induced by azoxymethane (AOM) and dextran sulfate sodium (DSS). Body weight, colon length, mucosal damage, tumor formation, and survival rate were assessed to determine the progression of UC-CRC. Western blot, quantitative real-time PCR, ELISA, immunohistochemistry, immunofluorescence and TUNEL were performed to examine the severity of inflammation and tumorigenesis. In vitro, LPS-treated mouse bone marrow-derived macrophages (BMDMs) and RAW264.7 cells were used to study the role of Pou3f1 in inflammation. ChIP and luciferase reporter assays were used to confirm the interaction between Nfatc3 and Pou3f1.

Results

Pou3f1 expression was increased in the colons of UC-CRC mice, and its inhibition attenuated mucosal injury, reduced colon tumorigenesis and increased survival ratio. Knockdown of Pou3f1 suppressed cell proliferation and increased cell death in colon tumors. Both the in vivo and in vitro results showed that Pou3f1 depletion reduced the production of proinflammation mediators. In addition, ChIP and luciferase reporter assays demonstrated that Nfatc3 directly bound with the Pou3f1 promoter to induce its expression. The effect of Nfatc3 on the inflammatory response in macrophages was suppressed by Pou3f1 knockdown.

Conclusion

Overall, it outlines that Pou3f1 mediates the role of Nfatc3 in regulating macrophage inflammation and carcinogenesis in UC-CRC development.

Supplementary Information

The online version contains supplementary material available at 10.1186/s11658-022-00374-0.

Nanomedicine and regenerative medicine approaches in osteoarthritis therapy

Osteoarthritis (OA), the most common chronic joint disease, is a degenerative disease that affects 7% of the worldwide population, more than 500 million people all over the world. OA is the main factor of disability in elderly people which decreases the quality of life of patients. It is characterized by joint pain, low bone density, and deterioration of the joint structure. Despite ongoing novel advances in drug discovery and drug delivery, OA therapy is still a big challenge since there is no available effective treatment and the existing therapies mainly focus on pain and symptomatic management rather than improving and/or suppressing its progression. This review aims to summarize the currently available and novel emerging therapies for OA including regenerative medicine and nanotechnology-based materials and formulations at the clinical and experimental levels. Applications of regenerative medicine and novel technologies such as nanotechnology in OA treatments have opened a new window to support OA patients by offering treatments that could halt or delay OA progression satisfactorily or provide an effective cure in near future. Nanomedicine and regenerative medicine suggest novel alternatives in the regeneration of cartilage, repair of bone damage, and control of chronic pain in OA therapy.

Tumor-Associated Inflammation: The Tumor-Promoting Immunity in the Early Stages of Tumorigenesis

Tumorigenesis is a multistage progressive oncogenic process caused by alterations in the structure and expression level of multiple genes. Normal cells are continuously endowed with new capabilities in this evolution, leading to subsequent tumor formation. Immune cells are the most important components of inflammation, which is closely associated with tumorigenesis. There is a broad consensus in cancer research that inflammation and immune response facilitate tumor progression, infiltration, and metastasis via different mechanisms; however, their protumor effects are equally important in tumorigenesis at earlier stages. Previous studies have demonstrated that during the early stages of tumorigenesis, certain immune cells can promote the formation and proliferation of premalignant cells by inducing DNA damage and repair inhibition, releasing trophic/supporting signals, promoting immune escape, and activating inflammasomes, as well as enhance the characteristics of cancer stem cells. In this review, we focus on the potential mechanisms by which immune cells can promote tumor initiation and promotion in the early stages of tumorigenesis; furthermore, we discuss the interaction of the inflammatory environment and protumor immune cells with premalignant cells and cancer stem cells, as well as the possibility of early intervention in tumor formation by targeting these cellular mechanisms.

Liposome encapsulated clodronate mediated elimination of pathogenic macrophages and microglia: A promising pharmacological regime to defuse cytokine storm in COVID-19

The emergence of new SARS-CoV-2 variants continues to pose an enormous public health concern. The SARS-CoV-2 infection disrupted host immune response accounting for cytokine storm has been linked to multiorgan failure and mortality in a significant portion of positive cases. Abruptly activated macrophages have been identified as the key pathogenic determinant of cytokine storm in COVID-19. Besides, reactive microglia have been known to discharge a surplus amount of proinflammatory factors leading to neuropathogenic events in the brains of SARS-CoV-2 infected individuals. Considering the fact, depletion of activated macrophages and microglia could be proposed to eradicate the life-threatening cytokine storm in COVID-19. Clodronate, a non-nitrogenous bisphosphonate drug has been identified as a potent macrophage and microglial depleting agent. While recent advancement in the field of liposome encapsulation technology offers the most promising biological tool for drug delivery, liposome encapsulated clodronate has been reported to effectively target and induce prominent phagocytic cell death in activated macrophages and microglia compared to free clodronate molecules. Thus, in this review article, we emphasize that depletion of activated macrophages and microglial cells by administration of liposome encapsulated clodronate can be a potential therapeutic strategy to diminish the pathogenic cytokine storm and alleviate multiorgan failure in COVID-19. Moreover, recently developed COVID-19 vaccines appear to render the chronic activation of macrophages accounting for immunological dysregulation in some cases. Therefore, the use of liposome encapsulated clodronate can also be extended to the clinical management of unforeseen immunogenic reactions resulting from activated macrophages associated adverse effects of COVID-19 vaccines.

Cellular Carcinogenesis: Role of Polarized Macrophages in Cancer Initiation

Simple Summary

Inflammation is a hallmark of many cancers. Macrophages are key participants in innate immunity and important drivers of inflammation. When chronically polarized beyond normal homeostatic responses to infection, injury, or aging, macrophages can express several pro-carcinogenic phenotypes. In this review, evidence supporting polarized macrophages as endogenous sources of carcinogenesis is discussed. In addition, the depletion or modulation of macrophages by small molecule inhibitors and probiotics are reviewed as emerging strategies in cancer prevention.

Abstract

Inflammation is an essential hallmark of cancer. Macrophages are key innate immune effector cells in chronic inflammation, parainflammation, and inflammaging. Parainflammation is a form of subclinical inflammation associated with a persistent DNA damage response. Inflammaging represents low-grade inflammation due to the dysregulation of innate and adaptive immune responses that occur with aging. Whether induced by infection, injury, or aging, immune dysregulation and chronic macrophage polarization contributes to cancer initiation through the production of proinflammatory chemokines/cytokines and genotoxins and by modulating immune surveillance. This review presents pre-clinical and clinical evidence for polarized macrophages as endogenous cellular carcinogens in the context of chronic inflammation, parainflammation, and inflammaging. Emerging strategies for cancer prevention, including small molecule inhibitors and probiotic approaches, that target macrophage function and phenotype are also discussed.

Macrophage depletion alters bacterial gut microbiota partly through fungal overgrowth in feces that worsens cecal ligation and puncture sepsis mice

Because macrophage dysfunction from some emerging therapies might worsen gut-derived sepsis, cecal ligation and puncture (CLP) sepsis are performed in mice with clodronate-induced macrophage depletion. Macrophage depletion (non-sepsis) increased fecal Ascormycota, with a subtle change in bacterial microbiota, that possibly induced gut-barrier defect as Candida pintolopesii and Enterococcus faecalis were identified from blood. Sepsis in macrophage-depleted mice was more severe than sepsis control as indicated by mortality, cytokines, organ injury (liver, kidney, and spleen), gut-leakage (FITC-dextran), fecal Proteobacteria, and blood organisms (bacteria and fungi). Lysate of C. pintolopesii or purified (1 → 3)-β-d-glucan (BG; a major component of fungal cell wall) enhanced growth of Klebsiella pneumoniae and Escherichia coli that were isolated from the blood of macrophage-depleted CLP mice implying a direct enhancer to some bacterial species. Moreover, the synergy of LPS and BG on enterocytes (Caco-2) (Transepithelial electrical resistance) and neutrophils (cytokines) also supported an influence of gut fungi in worsening sepsis. In conclusion, macrophage depletion enhanced sepsis through the selectively facilitated growth of some bacteria (dysbiosis) from increased fecal fungi that worsened gut-leakage leading to the profound systemic responses against gut-translocated LPS and BG. Our data indicated a possible adverse effect of macrophage-depleted therapies on enhanced sepsis severity through spontaneous elevation of fecal fungi.

Disordered Gut Microbiota in Colorectal Tumor-Bearing Mice Altered Serum Metabolome Related to Fufangchangtai

Purpose: This study aimed to investigate the relationship between gut microbiota (GM) and serum metabolism using antineoplastic Fufangchangtai (FFCT) as the model prescription in the treatment of colorectal cancer (CRC).

Methods: Tumor-bearing mice and normal mice were administered different doses of FFCT. The tumor volume of tumor-bearing mice was observed. The levels of CD4+ and CD8+ T cells in the blood, spleen, and tumor of mice were determined using a flow cytometer. The bacterial microbiota in stool samples from mice and the serum metabolomics of FFCT-treated mice and fecal microbiota transplantation mice were detected using 16s RNA sequencing and liquid chromatography–mass spectrometry (LC/MS), respectively.

Results: The tumor volume of mice showed no significant decrease after FFCT intervention. The levels of CD4+ and CD8+T lymphocytes showed a significant increase under the intervention of FFCT. GM of colorectal tumor-bearing mice and healthy mice were determined, and the diversity and abundance of Firmicutes, Deferribacteres, Bacteroidetes, and Proteobacteria were significantly different between the two groups. Furthermore, we found that the levels of matrine, isogingerenone B, and armillaripin were significantly decreased in tumor-bearing mice after FFCT intervention, indicating that the tumor-induced dysbiosis of gut bacteria may affect the absorption and metabolism of FFCT. Under the intervention of FFCT, serum metabolism of mice transplanted with feces from CRC patients showed less metabolites related to FFCT than that from healthy people, indicating that GM could be a single factor affecting the metabolism of FFCT. Furthermore, we found that different doses of FFCT-treated mice had higher abundance of Roseburia, Turicibacter, and Flexispira than that in the non-intervention control group. Firmicutes and Bacteroidetes in FFCT-treated groups showed a similar trend compared to the healthy group, indicating that FFCT might correct the intestinal microenvironment by modulating gut microbiota in colorectal tumor-bearing mice.

Conclusion: The dysbiosis of GM in tumor-bearing mice reduced the serum metabolites related to FFCT, and FFCT could correct the disordered GM of colorectal tumor-bearing mice to exert efficacy.

mbDenoise: microbiome data denoising using zero-inflated probabilistic principal components analysis

The analysis of microbiome data has several technical challenges. In particular, count matrices contain a large proportion of zeros, some of which are biological, whereas others are technical. Furthermore, the measurements suffer from unequal sequencing depth, overdispersion, and data redundancy. These nuisance factors introduce substantial noise. We propose an accurate and robust method, mbDenoise, for denoising microbiome data. Assuming a zero-inflated probabilistic PCA (ZIPPCA) model, mbDenoise uses variational approximation to learn the latent structure and recovers the true abundance levels using the posterior, borrowing information across samples and taxa. mbDenoise outperforms state-of-the-art methods to extract the signal for downstream analyses.

Emodin reduces tumor burden by diminishing M2-like macrophages in colorectal cancer

Emodin, a natural anthraquinone, has been shown to have antitumorigenic properties and may be an effective therapy for colorectal cancer (CRC). However, its clinical development has been hampered by a poor understanding of its mechanism of action. The purpose of this study was to 1) evaluate the efficacy of emodin in mouse models of intestinal/colorectal cancer and 2) to examine the impact of emodin on macrophage behavior in the context of CRC. We used a genetic model of intestinal cancer (Apc^Min/+) and a chemically induced model of CRC [azoxymethane/dextran sodium sulfate (AOM/DSS)]. Emodin was administered orally (40 or 80 mg/kg in AOM/DSS and 80 mg/kg in Apc^Min/+) three times a week to observe its preventative effects. Emodin reduced polyp count and size in both rodent models (P < 0.05). We further analyzed the colon microenvironment of AOM/DSS mice and found that mice treated with emodin exhibited lower protumorigenic M2-like macrophages and a reduced ratio of M2/M1 macrophages within the colon (P < 0.05). Despite this, we did not detect any significant changes in M2-associated cytokines (IL10, IL4, and Tgfb1) nor M1-associated cytokines (IL6, TNFα, IL1β, and IFNγ) within excised polyps. However, there was a significant increase in NOS2 expression (M1 marker) in mice treated with 80 mg/kg emodin (P < 0.05). To confirm emodin's effects on macrophages, we exposed bone marrow-derived macrophages (BMDMs) to C26 colon cancer cell conditioned media. Supporting our in vivo data, emodin reduced M2-like macrophages. Overall, these data support the development of emodin as a natural compound for prevention of CRC given its ability to target protumor macrophages.NEW & NOTEWORTHY Our study confirms that emodin is an effective primary therapy against the onset of genetic and chemically induced sporadic colorectal cancer. We established that emodin reduces the M2-like protumorigenic macrophages in the tumor microenvironment. Furthermore, we provide evidence that emodin may be acting to antagonize the P2X7 receptor within the bone tissue and consequently decrease the activation of proinflammatory cells, which may have implications for recruitment of cells to the tumor microenvironment.

A Special Network Comprised of Macrophages, Epithelial Cells, and Gut Microbiota for Gut Homeostasis

A number of gut epithelial cells derived immunological factors such as cytokines and chemokines, which are stimulated by the gut microbiota, can regulate host immune responses to maintain a well-balance between gut microbes and host immune system. Multiple specialized immune cell populations, such as macrophages, dendritic cells (DCs), innate lymphoid cells, and T regulatory (Treg) cells, can communicate with intestinal epithelial cells (IEC) and/or the gut microbiota bi-directionally. The gut microbiota contributes to the differentiation and function of resident macrophages. Situated at the interface between the gut commensals and macrophages, the gut epithelium is crucial for gut homeostasis in microbial recognition, signaling transformation, and immune interactions, apart from being a physical barrier. Thus, three distinct but interactive components—macrophages, microbiota, and IEC—can form a network for the delicate and dynamic regulation of intestinal homeostasis. In this review, we will discuss the crucial features of gut microbiota, macrophages, and IEC. We will also summarize recent advances in understanding the cooperative and dynamic interactions among the gut microbiota, gut macrophages, and IEC, which constitute a special network for gut homeostasis.

Heparin-binding protein (HBP) worsens the severity of pancreatic necrosis via up-regulated M1 macrophages activation in acute pancreatitis mouse models

Acute pancreatitis (AP) is one of the most widespread clinical emergencies. Macrophages are the most common immune cells in AP pancreatic tissue and are closely associated with pancreatic necrosis and recovery. The level of heparin-binding protein (HBP) is closely linked to inflammation. In this study, we assessed the effect of HBP on AP tissue necrosis severity and whether HBP is associated with M1 macrophages in pancreatic necrosis. We observed the dynamic changes of HBP levels in the pancreas during acute inflammation in the caerulein-induced AP mice model. We used hematoxylin-eosin staining to evaluate pancreatic edema and necrosis, and to detect infiltration of macrophages by immunohistochemistry. Moreover, expressions of the maker and cytokines of macrophages, including inducible nitric oxide synthase (iNOS), and arginase 1 (Arg-1), interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) mRNA, were detected by real-time polymerase-chain reaction (RT-PCR). High levels of HBP in the pancreas were detected at 48 h, and heparin inhibited HBP expression in AP pancreatic tissue. Inhibiting HBP expression by injecting heparin before AP can alleviate pancreatic necrosis and inhibit F4/80 labeled M1 macrophage infiltration and IL-6, TNF-α, and iNOS mRNA expression. Clodronate liposome (CLDL) intraperitoneally treated mice showed no change in pancreatic HBP levels, but pancreatic macrophage-specific antigen F4/80 and TNF-α, IL-1β, and IL-6 mRNA levels decreased after CLDL treatment. HBP is critical for pancreatic necrosis response in acute pancreatitis by increasing the infiltration of M1 macrophages and promoting the secretion of inflammatory factors, such as TNF-α, IL-6, IL-1β, which can be reduced by heparin.

Parasite-Derived Excretory-Secretory Products Alleviate Gut Microbiota Dysbiosis and Improve Cognitive Impairment Induced by a High-Fat Diet

High-fat (HF) diet-induced neuroinflammation and cognitive decline in humans and animals have been associated with microbiota dysbiosis via the gut-brain axis. Our previous studies revealed that excretory-secretory products (ESPs) derived from the larval Echinococcus granulosus (E. granulosus) function as immunomodulators to reduce the inflammatory response, while the parasitic infection alleviates metabolic disorders in the host. However, whether ESPs can improve cognitive impairment under obese conditions remain unknown. This study aimed to investigate the effects of E. granulosus-derived ESPs on cognitive function and the microbiota-gut-brain axis in obese mice. We demonstrated that ESPs supplementation prevented HF diet-induced cognitive impairment, which was assessed behaviorally by nest building, object location, novel object recognition, temporal order memory, and Y-maze memory tests. In the hippocampus (HIP) and prefrontal cortex (PFC), ESPs suppressed neuroinflammation and HF diet-induced activation of the microglia and astrocytes. Moreover, ESPs supplementation improved the synaptic ultrastructural impairments and increased both pre- and postsynaptic protein levels in the HIP and PFC compared to the HF diet-treated group. In the colon, ESPs reversed the HF diet-induced gut barrier dysfunction, increased the thickness of colonic mucus, upregulated the expression of zonula occludens-1 (ZO-1), attenuated the translocation of bacterial endotoxins, and decreased the colon inflammation. Notably, ESPs supplementation alleviated the HF diet-induced microbiota dysbiosis. After clarifying the role of antibiotics in obese mice, we found that broad-spectrum antibiotic intervention abrogated the effects of ESPs on improving the gut microbiota dysbiosis and cognitive decline. Overall, the present study revealed for the first time that the parasite-derived ESPs alleviate gut microbiota dysbiosis and improve cognitive impairment induced by a high-fat diet. This finding suggests that parasite-derived molecules may be used to explore novel drug candidates against obesity-associated neurodegenerative diseases.