N-acetyltransferase 10 affects the proliferation of intrahepatic cholangiocarcinoma and M2-type polarization of macrophages by regulating C-C motif chemokine ligand 2.

BACKGROUND: N-acetyltransferase 10 (NAT10) plays a crucial role in the occurrence and development of various tumors. However, the current regulatory mechanism of NAT10 in tumors is limited to its presence in tumor cells. Here, we aimed to reveal the role of NAT10 in intrahepatic cholangiocarcinoma (ICC) and investigate its effect on macrophage polarization in the tumor microenvironment (TME). METHODS: The correlation between NAT10 and ICC clinicopathology was analyzed using tissue microarray (TMA), while the effect of NAT10 on ICC proliferation was verified in vitro and in vivo. Additionally, the downstream target of NAT10, C-C motif chemokine ligand 2 (CCL2), was identified by Oxford Nanopore Technologies full-length transcriptome sequencing, RNA immunoprecipitation-quantitative polymerase chain reaction, and coimmunoprecipitation experiments. It was confirmed by co-culture that ICC cells could polarize macrophages towards M2 type through the influence of NAT10 on CCL2 protein expression level. Through RNA-sequencing, molecular docking, and surface plasmon resonance (SPR) assays, it was confirmed that berberine (BBR) can specifically bind CCL2 to inhibit ICC development. RESULTS: High expression level of NAT10 was associated with poor clinicopathological manifestations of ICC. In vitro, the knockdown of NAT10 inhibited the proliferative activity of ICC cells and tumor growth in vivo, while its overexpression promoted ICC proliferation. Mechanically, by binding to CCL2 messenger RNA, NAT10 increased CCL2 protein expression level in ICC and their extracellular matrix, thereby promoting the proliferation of ICC cells and M2-type polarization of macrophages. BBR can target CCL2, inhibit ICC proliferation, and reduce M2-type polarization of macrophages. CONCLUSIONS: NAT10 promotes ICC proliferation and M2-type polarization of macrophages by up-regulating CCL2, whereas BBR inhibits ICC proliferation and M2-type polarization of macrophages by inhibiting CCL2.

CCL2/CCR2 axis promotes perineural invasion of salivary adenoid cystic carcinoma via ITGß5-mediated nerve-tumor interaction.

Perineural invasion (PNI) is a notorious feature of salivary adenoid cystic carcinoma (SACC) and other neurotropic tumors. The pathogenesis of PNI that involves the molecular communication between the tumor and the suffered nerve is elusive. The in vitro co-culture assays of SACC cells with dorsal root ganglia (DRG) or neural cells showed that nerve-derived CCL2 activated CCR2 expression in SACC cells, promoting the proliferation, adhesion, migration, and invasion of SACC cells via the ERK1/2/ITGß5 pathway. Meanwhile, SACC-derived exosomes delivered ITGß5 to promote the neurite outgrowth of neural cells or DRG. Blocking of CCL2/CCR2 axis or ITGß5 inhibited the PNI of SACC cells in models in vitro by 3D co-culture of DRG with SACC cells and in vivo by xenografting SACC cells onto the murine sciatic nerve. High levels of ITGß5 in tissues or plasma exosomes were significantly correlated with CCL2 and CCR2 expression in the tissues and associated with PNI and poor prognosis of SACC cases. Our findings revealed a novel reciprocal loop between neural and tumor cells driven by the CCL2/CCR2 axis and exosomal ITGß5 during PNI of SACC. The present study may provide a prospective diagnostic and anti-PNI treatment strategy for SACC patients via targeting the nerve-tumor interactions.

Exploration of the mechanism of Taohong Siwu Decoction for the treatment of ischemic stroke based on CCL2/CCR2 axis.

Background and aims: Taohong Siwu Decoction (THSWD) is a traditional Chinese herbal prescription that is effective for ischemic stroke, Whether THSWD regulates the CCL2/CCR2 axis and thus reduces the inflammatory response induced by ischemic stroke is not known. The aim of this study was to elucidate the mechanism of action of THSWD in the treatment of ischemic stroke using bioinformatics combined with in vitro and in vivo experiments. Methods: R language was used to analyze middle cerebral artery occlusion/reperfusion (MCAO/R) rat transcriptome data and to identify differential gene expression following THSWD treatment. Gene set enrichment analysis (GSEA) was used to analyze the gene set enrichment pathway of MCAO/R rats treated with THSWD. PPI networks screened key targets. The Human Brain Microvascular Endothelial Cells (HBMEC) Oxygen Glucose Deprivation/Reoxygenation (OGD/R) model and SD rat models of MCAO/R were established. FITC-dextran, immunofluorescence, flow cytometry, ELISA, immunohistochemistry, Western blotting, and RT-qPCR were performed to identify potential treatment targets. Results: A total of 515 differentially expressed genes of THSWD in MCAO/R rats were screened and 92 differentially expressed genes of THSWD potentially involved in stroke intervention were identified, including Cd68, Ccl2, and other key genes. In vitro, THSWD reversed the increase in permeability of HBMEC cells and M1/M2 polarization of macrophages induced by CCL2/CCR2 axis agonists. In vivo, THSWD improved nerve function injury and blood-brain barrier injury in MCAO/R rats. Further, THSWD inhibited the infiltration and polarization of macrophages, reduced the expression of IL-6, TNF-α, and MMP-9, and increased the expression of IL-4, while reducing the gene and protein expression of CCL2 and CCR2. Conclusion: THSWD may play a protective role in ischemic stroke by inhibiting the CCL2/CCR2 axis, reducing the infiltration of macrophages, and promoting the polarization of M2 macrophages, thereby reducing inflammatory damage, and protecting injury to the blood-brain barrier.

Focal Cerebral Ischemia Induces Expression of Glutaminyl Cyclase along with Downstream Molecular and Cellular Inflammatory Responses.

Glutaminyl cyclase (QC) and its isoenzyme (isoQC) catalyze the formation of N-terminal pyroglutamate (pGlu) from glutamine on a number of neuropeptides, peptide hormones and chemokines. Chemokines of the C-C ligand (CCL) motif family are known to contribute to inflammation in neurodegenerative conditions. Here, we used a model of transient focal cerebral ischemia to explore functional, cellular and molecular responses to ischemia in mice lacking genes for QC, isoQC and their substrate CCL2. Mice of the different genotypes were evaluated for functional consequences of stroke, infarct volume, activation of glia cells, and for QC, isoQC and CCL2 expression. The number of QC-immunoreactive, but not of isoQC-immunoreactive, neurons increased robustly in the infarct area at 24 and 72 h after ischemia. In parallel, immunohistochemical signals for the QC substrate CCL2 increased from 24 to 72 h after ischemia induction without differences between genotypes analyzed. The increase in CCL2 was accompanied by morphological activation of Iba1-immunoreactive microglia and recruitment of MHC-II-positive cells at 72 h after ischemia. Among other chemokines quantified in the brain tissue, CCL17 showed higher concentrations at 72 h compared to 24 h after ischemia. Collectively, these data suggest a critical role for QC in inflammatory processes in the stroke-affected brain.

The effects of chronic, continuous ß-funaltrexamine pre-treatment on lipopolysaccharide-induced inflammation and behavioral deficits in C57BL/6J mice.

BACKGROUND: Inflammation and neuroinflammation are integral to the progression and severity of many diseases and are strongly associated with cardiovascular disease, cancer, autoimmune disorders, neurodegenerative disease, and neuropsychiatric disorders. These diseases can be difficult to treat without addressing the underlying inflammation, and, as such, a growing need has arisen for pharmaceutical treatments that target inflammatory mediators and signaling pathways. Our lab has investigated the therapeutic potential of the irreversible µ-opioid antagonist ß-funaltrexamine (ß-FNA) and discovered that acute treatment ameliorates inflammation in astrocytes in vitro and inhibits central and peripheral inflammation and reduces anxiety- and sickness-like behavior in male C57BL/6J mice. Now, our investigation has expanded to investigate the chronic pre-treatment effects of ß-FNA on lipopolysaccharide (LPS)-induced inflammation and behavior in male C57BL/6J mice. RESULTS: Micro-osmotic drug pumps were surgically inserted into the subcutaneous intrascapular space of male C57BL/6J mice. ß-FNA or saline vehicle was continuously administered for seven days. On the sixth day, mice were given intraperitoneal injections of LPS or saline. An elevated plus maze test, followed by a forced swim test, were administered 24 h post-injection to measure sickness-, anxiety- and depressive-like behavior. Immediately after testing, frontal cortex, hippocampus, spleen, and plasma were collected. Levels of inflammatory chemokines C-C motif chemokine ligand 2 (CCL2) and C-X-C motif chemokine ligand 10 (CXCL10) were measured in tissues by enzyme-linked immunosorbent assay (ELISA). Quantitative reverse transcription polymerase chain reaction (RT-qPCR) was used to assess expression of the enzyme indoleamine 2, 3-dioxygenase 1 (IDO1) and the NLR family pyrin domain-containing protein 3 (NRLP3) inflammasome in frontal cortex and spleen tissues. Chronic pre-treatment robustly decreased inflammation in the hippocampus, frontal cortex, and spleen and reduced or abolished anxiety- and sickness-like behavior (e.g., increased time spent motionless, increased time spent in a contracted position, and reduced distance moved). However, treatment with ß-FNA alone increased both inflammation in the frontal cortex and anxiety-like behavior. CONCLUSION: These findings provide novel insights into the anti-inflammatory and behavior-modifying effects of chronic ß-FNA pre-treatment and continue to support the therapeutic potential of ß-FNA under inflammatory conditions.

Microglia depletion and repopulation do not alter the effects of cranial irradiation on hippocampal neurogenesis.

Cranial radiotherapy can cause lifelong cognitive complications in childhood brain tumor survivors, and reduced hippocampal neurogenesis is hypothesized to contribute to this. Following irradiation (IR), microglia clear dead neural progenitors and give rise to a neuroinflammatory microenvironment, which promotes a switch in surviving progenitors from neuronal to glial differentiation. Recently, depletion and repopulation of microglia were shown to promote neurogenesis and ameliorate cognitive deficits in various brain injury models. In this study, we utilized the Cx3cr1CreERt2-YFP/+Rosa26DTA/+ transgenic mouse model to deplete microglia in the juvenile mouse brain before subjecting them to whole-brain IR and investigated the short- and long-term effects on hippocampal neurogenesis. Within the initial 24 h after IR, the absence of microglia led to an accumulation of dead cells in the subgranular zone, and 50-fold higher levels of the chemokine C-C motif ligand 2 (CCL2) in sham brains and 7-fold higher levels after IR. The absence of microglia, and the subsequent repopulation within 10 days, did neither affect the loss of proliferating or doublecortin-positive cells, nor the reduced growth of the granule cell layer. Our results argue against a role for a pro-inflammatory microenvironment in the dysregulation of hippocampal neurogenesis and suggest that the observed reduction of neurogenesis was solely due to IR.

Intranasal vaccination with engineered BCG expressing CCL2 induces a stronger immune barrier against Mycobacterium tuberculosis than BCG.

Intradermal Mycobacterium bovis Bacillus Calmette-Guérin (BCG) vaccination is currently the only licensed strategy for preventing tuberculosis (TB). It provides limited protection against pulmonary TB. To enhance the efficacy of BCG, we developed a recombinant BCG expressing exogenous monocyte chemoattractant CC chemokine ligand 2 (CCL2) called rBCG-CCL2. Co-culturing macrophages with rBCG-CCL2 enhances their abilities in migration, phagocytosis, and effector molecule expression. In the mouse model, intranasal vaccination with rBCG-CCL2 induced greater immune cell infiltration and a more extensive innate immune response in lung compared to vaccination with parental BCG, as determined by multiparameter flow cytometry, transcriptomic analysis, and pathological assessments. Moreover, rBCG-CCL2 induced a high frequency of activated macrophages and antigen-specific T helper 1 (Th1) and Th17 T cells in lungs. The enhanced immune microenvironment responded more effectively to intravenous challenge with Mycobacterium tuberculosis (Mtb) H37Ra, leading to significant reductions in H37Ra burden and pathological damage to the lungs and spleen. Intranasal rBCG-CCL2-vaccinated mice rapidly initiated pro-inflammatory Th1 cytokine release and reduced pathological damage to the lungs and spleen during the early stage of H37Ra challenge. The finding that co-expression of CCL2 synergistically enhances the immune barrier induced by BCG provides a model for defining immune correlates and mechanisms of vaccine-elicited protection against TB.

Hdac3 deficiency limits periosteal reaction associated with Western diet feeding in female mice.

Diet-induced obesity is associated with enhanced systemic inflammation that limits bone regeneration. HDAC inhibitors are currently being explored as anti-inflammatory agents. Prior reports show that myeloid progenitor-directed Hdac3 ablation enhances intramembranous bone healing in female mice. In this study, we determined if Hdac3 ablation increased intramembranous bone regeneration in mice fed a high-fat/high-sugar (HFD) diet. Micro-CT analyses demonstrated that HFD-feeding enhanced the formation of periosteal reaction tissue of control littermates, reflective of suboptimal bone healing. We confirmed enhanced bone volume within the defect of Hdac3-ablated females and showed that Hdac3 ablation reduced the amount of periosteal reaction tissue following HFD feeding. Osteoblasts cultured in a conditioned medium derived from Hdac3-ablated cells exhibited a four-fold increase in mineralization and enhanced osteogenic gene expression. We found that Hdac3 ablation elevated the secretion of several chemokines, including CCL2. We then confirmed that Hdac3 deficiency increased the expression of Ccl2. Lastly, we show that the proportion of CCL2-positve cells within bone defects was significantly higher in Hdac3-deficient mice and was further enhanced by HFD. Overall, our studies demonstrate that Hdac3 deletion enhances intramembranous bone healing in a setting of diet-induced obesity, possibly through increased production of CCL2 by macrophages within the defect.

Pirfenidone inhibits CCL2-mediated Treg chemotaxis induced by palbociclib and fulvestrant in HR+/HER2- breast cancer.

In human epidermal growth factor receptor 2-negative (HR+/HER2-) breast cancer, the most prevalent subtype, the pathological complete response (pCR) rate after neoadjuvant chemotherapy is less than 18 %, and the survival of patients with advanced-stage disease is approximately 34 %, highlighting the critical demand for more potent therapies. Recent research has underscored the substantial therapeutic benefits of the combination of CDK4/6 inhibitors and fulvestrant (Ful) in managing HR+/HER2- breast cancer. These therapeutics not only curtail tumor proliferation but also alter the tumor immune microenvironment, suggesting novel avenues for immunotherapy for this breast cancer subtype. Flow cytometry, PCR, WB, and RNA-seq experiments revealed that the combination of the CDK4/6 inhibitor palbociclib (Pal) with Ful upregulated CCL2 in tumor cells by inducing the SASP and activating the MAPK signaling pathway. CCL2 attracts Tregs to the tumor microenvironment, where it exerts an immunosuppressive effect. By administering the CCL2 inhibitor pirfenidone, we inhibited these effects and enhanced the antitumor efficacy of Pal + Ful. Our research revealed an immunosuppressive effect of CDK4/6 inhibitors and fulvestrant and suggested that CCL2 inhibitors may be a viable approach for treating patients with advanced HR+/HER2- breast cancer.

Message Transmission Between Adipocyte and Macrophage in Obesity.

Obesity is characterized by the chronic low-grade activation of the innate immune system. In this respect, macrophage-elicited metabolic inflammation and adipocyte-macrophage interaction have primary importance in obesity. Large quantity of macrophages is accumulated by different mechanisms in obese adipose tissue. Hypertrophic adipocyte-derived chemotactic monocyte chemoattractant protein-1 (MCP-1)/C-C chemokine receptor 2 (CCR2) pathway promotes more macrophage accumulation into the obese adipose tissue. However, obesity-induced changes in adipose tissue macrophage density are mainly dependent on increases in the triple-positive cluster of differentiation (CD)11b+ F4/80+ CD11c+ adipose tissue macrophage subpopulation. As epigenetic regulators, microRNAs (miRNAs) are one of the most important mediators of obesity. miRNAs are expressed by adipocytes as well as macrophages and regulate inflammation with the expression of target genes. A paracrine loop involving free fatty acids and tumor necrosis factor-alpha (TNF-α) between adipocytes and macrophages establishes a vicious cycle that aggravates inflammatory changes in the adipose tissue. Adipocyte-specific caspase-1 and production of interleukin-1beta (IL-1ß) by macrophages; both adipocyte and macrophage induction by toll-like receptor-4 (TLR4) through nuclear factor-kappaB (NF-κB) activation; free fatty acid-induced and TLR-mediated activation of c-Jun N-terminal kinase (JNK)-related pro-inflammatory pathways in CD11c+ immune cells; are effective in mutual message transmission between adipocyte and macrophage and in the development of adipose tissue inflammation. Thus, the metabolic status of adipocytes and their released exosomes are important determinants of macrophage inflammatory output. However, old adipocytes are removed by macrophages through trogocytosis or sending an "eat me" signal. As a single miRNA can be able to regulate a variety of target genes and signaling pathways, reciprocal transfer of miRNAs between adipocytes and macrophages via miRNA-loaded exosomes reorganizes the different stages of obesity. Changes in the expression of circulating miRNAs because of obesity progression or anti-obesity treatment indicate that miRNAs could be used as potential biomarkers. Therefore, it is believed that targeting macrophage-associated miRNAs with anti-obesity miRNA-loaded nano-carriers may be successful in the attenuation of both obesity and adipose tissue inflammation in clinical practice. Moreover, miRNA-containing exosomes and transferable mitochondria between the adipocyte and macrophage are investigated as new therapeutic targets for obesity-related metabolic disorders.

Dipeptidyl peptidase 4 deficiency improves survival after focal cerebral ischemia in mice and ameliorates microglia activation and specific inflammatory markers.

Dipeptidyl peptidase 4 (DPP4; CD26) is involved in the regulation of various metabolic, immunological, and neurobiological processes in healthy individuals. Observations based on epidemiological data indicate that DPP4 inhibition by gliptins, typically used in patients with diabetes, may reduce the risk for cerebral ischemia and may also improve related outcomes. However, as DPP4 inhibitor application is neither complete nor specific for suppression of DPP4 enzymatic activity and DPP4 has non-enzymatic functions as well, the variety of consequences is a matter of debate. Therefore, we here used DPP4 knock-out (KO) mice to analyze the specific contribution of DPP4 to cellular, immunological, and functional consequences of experimental focal cerebral ischemia. We observed a significantly higher survival rate of DPP4 KO mice after ischemia, which was accompanied by a lower abundance of the pro-inflammatory chemokine CCL2 and reduced activation of Iba1-positive microglia cells in brain tissue of DPP4 KO mice. In addition, after ischemia for 24 h to 72 h, decreased concentrations of CCL5 and CCL12 in plasma and of CCL17 in brain tissue of DPP4 KO mice were observed when compared to wild type mice. Other aspects analyzed, such as the functional Menzies score, astrocyte activation and chemokine levels in plasma and brain tissue were affected by ischemia but appeared to be unaffected by the DPP4 KO genotype. Taken together, experimental ablation of DPP4 functions in mice improves survival and ameliorates aspects of cellular and molecular inflammation after focal cerebral ischemia.

A CCL2/MCP-1 antagonist attenuates fibrosis of the infrapatellar fat pad in a rat model of arthritis.

BACKGROUND: Fibrosis of the infrapatellar fat pad (IFP) is a feature of osteoarthritis and contributes substantially to the pain and dysfunction in patients' joints. However, the underlying mechanisms remain unclear. C-C motif chemokine ligand-2 (CCL2) plays a central role in tissue fibrosis. Thus, we aimed to investigate the role of CCL2 in the development of IFP fibrosis in a rat model of arthritis, hypothesizing that a CCL2 antagonist could mitigate fibrotic progression. METHODS: We induced arthritis in male Wistar rats using intra-articular injections of carrageenan. Furthermore, to evaluate the effects of a CCL2 antagonist on protein expression and collagen deposition in the IFP of the rats, we transferred an N-terminal-truncated CCL2 gene into a rat model via electroporation-mediated intramuscular injection. Macrophage infiltration and collagen deposition in the IFP were analyzed in vivo. Groups were compared using the Mann-Whitney U test and Student's t-test. RESULTS: We identified infiltrating macrophages as well as increases in CCL2 and TGF-ß levels as collagen deposition progressed. Gene transfer of the CCL2-antagonist before arthritis induction attenuated collagen deposition remarkably. CONCLUSIONS: We provide initial evidence that anti-CCL2 gene therapy can effectively suppress the development of IFP fibrosis in a rat model. Thus, targeting CCL2 holds promise as a therapeutic strategy for managing tissue fibrosis in osteoarthritis patients.

Corrigendum: YKL-40 promotes chemokine expression following drug-induced liver injury via TF-PAR1 pathway in mice.

[This corrects the article DOI: 10.3389/fphar.2023.1205062.].

Hesperidin PLGA nanoparticles potentiate the efficacy of aPD-1 in treating triple negative breast cancer by regulating CCL2 and ADPN expression in cancer-associated adipocytes.

Triple negative breast cancer (TNBC) represents a heterogeneous subtype of breast cancer characterized by an unfavorable prognosis due to its aggressive biology. Cancer-associated adipocytes (CAAs) play an active role in tumor development, invasion and metastasis, and response to treatment by secreting various cytokines. CAAs secrete CCL2 and ADPN which significantly affect the efficacy of aPD-1 in treating breast cancer. Our recent research has demonstrated that Hesperidin, a natural phenolic compound, significantly inhibits CCL2, elevates ADPN secreted by CAAs in vitro and in vivo, remodels the immune microenvironment, and potentiates the efficacy of aPD-1 in triple-negative breast cancer. We used Oil red staining, Bodipy 493/503 staining and quantitative real-time PCR to verify the formation of CAAs. ELISA was used to detect levels of CCL2, ADPN secreted by CAAs. Changes in the number of immune cells in mouse tumor tissues were detected using flow cytometry and immunofluorescence. Our data suggest that Hesperidin PLGA nanoparticles significantly reduced CCL2 and increased ADPN secreted by CAAs, which concurrently decreased the recruitment of M2 macrophages, Tregs and MDSCs while increased the infiltration of CD8+T cells, M1 macrophages and DCs into tumor, thus significantly potentiated the efficacy of aPD-1 in vivo. This study provides a new combined strategy for the clinical treatment of triple-negative breast cancer by interfering with CCL2, ADPN secreted by CAAs to enhance the efficacy of immunotherapy.

Sex chromosomes and hormones independently influence healthy brain development but act similarly after cranial radiation.

The course of normal development and response to pathology are strongly influenced by biological sex. For instance, female childhood cancer survivors who have undergone cranial radiation therapy (CRT) tend to display more pronounced cognitive deficits than their male counterparts. Sex effects can be the result of sex chromosome complement (XX vs. XY) and/or gonadal hormone influence. The contributions of each can be separated using the four-core genotype mouse model (FCG), where sex chromosome complement and gonadal sex are decoupled. While studies of FCG mice have evaluated brain differences in adulthood, it is still unclear how sex chromosome and sex hormone effects emerge through development in both healthy and pathological contexts. Our study utilizes longitudinal MRI with the FCG model to investigate sex effects in healthy development and after CRT in wildtype and immune-modified Ccl2-knockout mice. Our findings in normally developing mice reveal a relatively prominent chromosome effect prepubertally, compared to sex hormone effects which largely emerge later. Spatially, sex chromosome and hormone influences were independent of one another. After CRT in Ccl2-knockout mice, both male chromosomes and male hormones similarly improved brain outcomes but did so more separately than in combination. Our findings highlight the crucial role of sex chromosomes in early development and identify roles for sex chromosomes and hormones after CRT-induced inflammation, highlighting the influences of biological sex in both normal brain development and pathology.

Virus-Induced Host Chemokine CCL2 in COVID-19 Pathogenesis: Potential Prognostic Marker and Target of Anti-Inflammatory Strategy.

A wide variety of inflammatory mediators, mainly cytokines and chemokines, are induced during SARS CoV-2 infection. Among these proinflammatory mediators, chemokines tend to play a pivotal role in virus-mediated immunopathology. The C-C chemokine ligand 2 (CCL2), also known as monocyte chemoattractant protein-1 (MCP-1) is a potent proinflammatory cytokine and strong chemoattractant of monocytes, macrophages and CD4+ T cells bearing C-C chemokine receptor type-2 (CCR2). Besides controlling immune cell trafficking, CCL2 is also involved in multiple pathophysiological processes including systemic hyperinflammation associated cytokine release syndrome (CRS), organ fibrosis and blood coagulation. These pathological features are commonly manifested in severe and fatal cases of COVID-19. Given the crucial role of CCL2 in COVID-19 pathogenesis, the CCL2:CCR2 axis may constitute a potential therapeutic target to control virus-induced hyperinflammation and multi-organ dysfunction. Herein we describe recent advances on elucidating the role of CCL2 in COVID-19 pathogenesis, prognosis, and a potential target of anti-inflammatory interventions.

C-C Motif Chemokine Ligand 2 and Chemokine Receptor 2 in Cardiovascular and Neural Aging and Aging-Related Diseases.

Aging is a prominent risk factor for numerous chronic diseases. Understanding the shared mechanisms of aging can aid in pinpointing therapeutic targets for age-related disorders. Chronic inflammation has emerged as a pivotal mediator of aging and a determinant in various age-related chronic conditions. Recent findings indicate that C-C motif chemokine ligand 2 and receptor 2 (CCL2-CCR2) signaling, an important physiological modulator in innate immune response and inflammatory defense, plays a crucial role in aging-related disorders and is increasingly recognized as a promising therapeutic target, highlighting its significance. This review summarizes recent advances in the investigation of CCL2-CCR2 signaling in cardiovascular and neural aging, as well as in various aging-related disorders. It also explores the underlying mechanisms and therapeutic potentials in these contexts. These insights aim to deepen our understanding of aging pathophysiology and the development of aging-related diseases.

Deguelin inhibits the glioblastoma progression through suppressing CCL2/NFκB signaling pathway.

Glioblastoma multiforme (GBM) is the most common primary intracranial tumor with characteristics of high aggressiveness and poor prognosis. Deguelin, a component from the bark of Leguminosae Mundulea sericea (African plant), displays antiproliferative effects in some tumors, however, the inhibitory effect and mechanism of deguelin on GBM were still poorly understood. At first, we found that deguelin reduced the viability of GBM cells by causing cell cycle arrest in G2/M phase and inducing their apoptosis. Secondly, deguelin inhibited the migration of GBM cells. Next, RNA-seq analysis identified that CCL2 (encoding chemokine CCL2) was downregulated significantly in deguelin-treated GBM cells. As reported, CCL2 promoted the cell growth, and CCL2 was associated with regulating NFκB signaling pathway, as well as involved in modulating tumor microenvironment (TME). Furthermore, we found that deguelin inactivated CCL2/NFκB signaling pathway, and exougous CCL2 could rescue the anti-inhibitory effect of deguelin on GBM cells via upregulating NFκB. Finally, we established a syngeneic intracranial orthotopic GBM model and found that deguelin regressed the tumor growth, contributed to an anti-tumorigenic TME and inhibited angiogenesis of GBM by suppressing CCL2/NFκB in vivo. Taken together, these results suggest the anti-GBM effect of deguelin via inhibiting CCL2/NFκB pathway, which may provide a new strategy for the treatment of GBM.

Transient Inhibition of Translation Improves Cardiac Function After Ischemia/Reperfusion by Attenuating the Inflammatory Response.

BACKGROUND: The myocardium adapts to ischemia/reperfusion (I/R) by changes in gene expression, determining the cardiac response to reperfusion. mRNA translation is a key component of gene expression. It is largely unknown how regulation of mRNA translation contributes to cardiac gene expression and inflammation in response to reperfusion and whether it can be targeted to mitigate I/R injury. METHODS: To examine translation and its impact on gene expression in response to I/R, we measured protein synthesis after reperfusion in vitro and in vivo. Underlying mechanisms of translational control were examined by pharmacological and genetic targeting of translation initiation in mice. Cell type-specific ribosome profiling was performed in mice that had been subjected to I/R to determine the impact of mRNA translation on the regulation of gene expression in cardiomyocytes. Translational regulation of inflammation was studied by quantification of immune cell infiltration, inflammatory gene expression, and cardiac function after short-term inhibition of translation initiation. RESULTS: Reperfusion induced a rapid recovery of translational activity that exceeds baseline levels in the infarct and border zone and is mediated by translation initiation through the mTORC1 (mechanistic target of rapamycin complex 1)-4EBP1 (eIF4E-binding protein 1)-eIF (eukaryotic initiation factor) 4F axis. Cardiomyocyte-specific ribosome profiling identified that I/R increased translation of mRNA networks associated with cardiac inflammation and cell infiltration. Short-term inhibition of the mTORC1-4EBP1-eIF4F axis decreased the expression of proinflammatory cytokines such as Ccl2 (C-C motif chemokine ligand 2) of border zone cardiomyocytes, thereby attenuating Ly6Chi monocyte infiltration and myocardial inflammation. In addition, we identified a systemic immunosuppressive effect of eIF4F translation inhibitors on circulating monocytes, directly inhibiting monocyte infiltration. Short-term pharmacological inhibition of eIF4F complex formation by 4EGI-1 or rapamycin attenuated translation, reduced infarct size, and improved cardiac function after myocardial infarction. CONCLUSIONS: Global protein synthesis is inhibited during ischemia and shortly after reperfusion, followed by a recovery of protein synthesis that exceeds baseline levels in the border and infarct zones. Activation of mRNA translation after reperfusion is driven by mTORC1/eIF4F-mediated regulation of initiation and mediates an mRNA network that controls inflammation and monocyte infiltration to the myocardium. Transient inhibition of the mTORC1-/eIF4F axis inhibits translation and attenuates Ly6Chi monocyte infiltration by inhibiting a proinflammatory response at the site of injury and of circulating monocytes.

CCL2/CCR2 Expression in Locally Advanced Prostate Cancer and Patient Long-Term Outcome: 10-Year Results from the TROG 03.04 RADAR Trial.

This study investigated the prognostic value of the chemokine C-C motif ligand 2 (CCL2) and its receptor C-C motif chemokine receptor 2 (CCR2) expression in locally advanced prostate cancer treated with radiotherapy and androgen deprivation using the 10-year outcome data from the TROG 03.04 RADAR clinical trial. CCL2 and CCR2 protein expression in prostate cancer biopsies at the time of diagnosis were quantified by immunohistochemistry and digital quantification. CCR2 protein expression was detected in prostate cancer cells and was associated with prostate-specific antigen serum concentration (p = 0.045). However, neither CCL2 nor CCR2 tissue expression could predict prostate cancer progression, or other clinicopathological parameters including perineural invasion and patient outcome. In serum samples, CCL2 concentration at the time of diagnosis, as assayed by enzyme-linked immunosorbent assay, was significantly higher in patients with prostate cancer compared with benign prostatic hyperplasia (median difference 0.22 ng/mL, 95% CI, 0.17-0.30) (p < 0.0001) and normal controls (median difference 0.13 ng/mL, 95% CI, 0.13-0.17) (p < 0.0001). However, circulating CCL2 was not statistically significant as a predictor of disease progression and patient outcome. In conclusion, this study shows that although CCL2 and CCR2 are expressed in prostate cancer, with an increased level of CCL2 in the serum, neither CCL2 nor CCR2 expression has a clinical prognostic value in locally advanced prostate cancer.