Increased Macrophage Infiltration Research Articles

Schwann cell-derived CXCL2 contributes to cancer pain by modulating macrophage infiltration in a mouse breast cancer model

Pain is one of the most severe complications affecting the quality of life of cancer patients. Although substantial progress has been made in the diagnosis and treatment of cancer, the neurobiological mechanism of cancer pain is still unclear. In the present study, we identified the critical role of CXC chemokine 2 (CXCL2), released by Schwann cells after being activated by cancer cells, in maintaining cancer-induced macrophage infiltration and the resulting mechanical hypersensitivity and persistent spontaneous nociception. In vitro, Schwann cells cocultured with breast cancer cells exhibited a significant increase in CXCL2 expression; in addition, conditioned medium from Schwann cells activated by breast cancer cells had a similar effect to recombinant CXCL2 in terms of inducing macrophage migration. Targeting CXCL2 signaling by both CXC chemokine receptor 2 (CXCR2) antagonist pharmacological blockade and anti-CXCL2 mAb immunological blockade robustly prevented conditioned medium-induced macrophage migration. In vivo, both application of recombinant CXCL2 and perineural breast cancer cell implantation resulted in mechanical hypersensitivity and persistent spontaneous nociception in mice, along with increased macrophage infiltration into the sciatic nerves. Similar to the in vitro results, inhibition of CXCL2/CXCR2 signaling or conditional knockdown of CXCL2 in sciatic nerve Schwann cells effectively attenuated breast cancer cell-induced mechanical hypersensitivity, persistent spontaneous nociception, and macrophage recruitment in the sciatic nerve. Mechanistically, we found that redox effector factor-1 (Ref-1) secreted by breast cancer cells activated hypoxia inducible factor-1α (HIF-1α) expression and inhibited reactive oxygen species (ROS) production in Schwann cells, ultimately inducing CXCL2 expression in Schwann cells. In brief, the present study expands new insights into cancer pain mechanisms from promising animal models to provide new strategies for the control of cancer pain.

Human-specific duplicate CHRFAM7A gene is associated with more severe osteoarthritis and amplifies pain behaviours

ObjectivesCHRFAM7A is a uniquely human fusion gene that functions as a dominant negative regulator of alpha 7 acetylcholine nicotinic receptor (α7nAChR) in vitro. This study determined the impact of CHRFAM7A...

Ceruloplasmin-Deficient Mice Show Dysregulation of Lipid Metabolism in Liver and Adipose Tissue Reduced by a Protein Replacement

Ceruloplasmin is a ferroxidase that plays a role in iron homeostasis; its deficiency fosters inter alia iron accumulation in the liver, which expresses the soluble form of the protein secreted into the bloodstream. Ceruloplasmin is also secreted by the adipose tissue, but its role in adipocytes has been poorly investigated. We hypothesized that ceruloplasmin might have a role in iron/lipid interplay. We investigated iron/lipid dysmetabolism in the liver and adipose tissue of the ceruloplasmin-deficient mouse (CpKO) model of aceruloplasminemia and evaluated the effectiveness of ceruloplasmin replacement. We found that CpKO mice were overweight, showing adipose tissue accumulation, liver iron deposition and steatosis. In the adipose tissue of CpKO mice, iron homeostasis was not altered. Conversely, the levels of adiponectin and leptin adipokines behaved opposite to the wild-type. Increased macrophage infiltration was observed in adipose tissue and liver of CpKO mice, indicating tissue inflammation. The treatment of CpKO mice with ceruloplasmin limited liver iron accumulation and steatosis without normalizing the expression of iron homeostasis-related proteins. In the CpKO mice, the protein replacement limited macrophage infiltration in both adipose and hepatic tissues reduced the level of serum triglycerides, and partially recovered adipokines levels in the adipose tissue. These results underline the link between iron and lipid dysmetabolism in ceruloplasmin-deficient mice, suggesting that ceruloplasmin in adipose tissue has an anti-inflammatory role rather than a role in iron homeostasis. Furthermore, these data also indicate that ceruloplasmin replacement therapy may be effective at a systemic level.

Loss of tumor suppressor WWOX accelerates pancreatic cancer development through promotion of TGFβ/BMP2 signaling

Pancreatic cancer is one of the most lethal cancers, owing to its late diagnosis and resistance to chemotherapy. The tumor suppressor WW domain-containing oxidoreductase (WWOX), one of the most active fragile sites in the human genome (FRA16D), is commonly altered in pancreatic cancer. However, the direct contribution of WWOX loss to pancreatic cancer development and progression remains largely unknown. Here, we report that combined conditional deletion of Wwox and activation of KRasG12D in Ptf1a-CreER-expressing mice results in accelerated formation of precursor lesions and pancreatic carcinoma. At the molecular level, we found that WWOX physically interacts with SMAD3 and BMP2, which are known activators of the TGF-β signaling pathway. In the absence of WWOX, TGFβ/BMPs signaling was enhanced, leading to increased macrophage infiltration and enhanced cancer stemness. Finally, overexpression of WWOX in patient-derived xenografts led to diminished aggressiveness both in vitro and in vivo. Overall, our findings reveal an essential role of WWOX in pancreatic cancer development and progression and underscore its role as a bona fide tumor suppressor.

Itaconate promotes a wound resolving phenotype in pro-inflammatory macrophages

Pathological conditions associated with dysfunctional wound healing are characterized by impaired remodelling of extracellular matrix (ECM), increased macrophage infiltration, and chronic inflammation. Macrophages also play an important role in wound healing as they drive wound closure by secretion of molecules like transforming growth factor beta-1 (TGF-β). As the functions of macrophages are regulated by their metabolism, local administration of small molecules that alter this might be a novel approach for treatment of wound-healing disorders. Itaconate is a tricarboxylic acid (TCA) cycle-derived metabolite that has been associated with resolution of macrophage-mediated inflammation. However, its effects on macrophage wound healing functions are unknown. In this study, we investigated the effects of the membrane-permeable 4-octyl itaconate (4-OI) derivative on ECM scavenging by cultured human blood monocyte-derived macrophages (hMDM). We found that 4-OI reduced signalling of p38 mitogen-activated protein kinase (MAPK) induced by the canonical immune stimulus lipopolysaccharide (LPS). Likely as a consequence of this, the production of the inflammatory mediators like tumor necrosis factor (TNF)-α and cyclooxygenase (COX)-2 were also reduced. On the transcriptional level, 4-OI increased expression of the gene coding for TGF-β (TGFB1), whereas expression of the collagenase matrix metalloprotease-8 (MMP8) was reduced. Furthermore, surface levels of the anti-inflammatory marker CD36, but not CD206 and CD11c, were increased in these cells. To directly investigate the effect of 4-OI on scavenging of ECM by macrophages, we developed an assay to measure uptake of fibrous collagen. We observed that LPS promoted collagen uptake and that this was reversed by 4-OI-induced signaling of nuclear factor erythroid 2–related factor 2 (NRF2), a regulator of cellular resistance to oxidative stress and the reduced glycolytic capacity of the macrophage. These results indicate that 4-OI lowers macrophage inflammation, likely promoting a more wound-resolving phenotype.

Adipose tissue-derived small extracellular vesicles modulate macrophages to improve the homing of adipocyte precursors and endothelial cells in adipose tissue regeneration.

Rapid infiltration of endogenous cells induced by cell-free biomaterials is the first and crucial step in tissue regeneration and macrophage is largely involved. Our previous study reported adipose tissue-derived small extracellular vesicles (sEV-AT) could successfully promote adipose tissue regeneration. However, the role of macrophages in this process was unknown. In this study, we isolated sEV-AT and subcutaneously implanted it into the back of SD rats. The results showed sEV-AT increased macrophage infiltration significantly, which was followed by improving homing of adipocyte precursors (APs) and endothelial cells (ECs). However, when macrophages were depleted by clodronate liposome within 1 week, the homing of APs and ECs, and adipose tissue regeneration were destroyed. In vitro, sEV-AT showed the ability to promote the migration of macrophages directly. Besides, sEV-AT-pretreated macrophages improved the migration of APs and ECs, accompanied by the increase of chemokines (MCP-1, SDF-1, VEGF, and FGF) and the activation of NF-kB signaling pathway. These findings indicated sEV-AT might regulate the secretion of chemokines via activating NF-kB signaling pathway to improve homing of APs and ECs and facilitate adipose tissue regeneration. These findings deepened our understanding of small extracellular vesicle-induced tissue regeneration and laid a theoretical foundation for the clinical application of sEV-AT.

Nicotine ameliorates inflammatory mediators in RU486 induced preterm labor model through activating cholinergic anti-inflammatory pathway.

Preterm birth is a global public health threat. Inflammatory reaction is thought to mediate preterm birth. The role of nicotine, an anti-inflammatory agent that is mediated by cholinergic anti-inflammatory pathways (CAP), remains unclear in the pathogenesis. Pregnant rats were randomly divided into four groups (20 rats each): pregnant control group (P), RU486-treated group (PTL), RU486 and nicotine-treated group (PTL+N), RU486, nicotine and α-BGT treated group (PTL+N+A). Rats were administered RU486 (1.0mg/kg) by subcutaneous injection on gestational day (GD) 18 to establish PTL model. Subcutaneous injection of nicotine (1mg/kg) was administered daily from GD 16 to 18. α-BGT (1µg/kg) was administrated subcutaneously in two sessions and each session was 30min prior to nicotine. TNF-α, IL-1β, IL-4, IL-6, IL-10 in myometrium and serum were detected by Luminex. Macrophage infiltration and α7nAChR were detected by IHC. We established a RU486-induced preterm labor rat model. Preterm labor was associated with a striking upregulation inflammatory mediators and increased macrophage infiltration. Nicotine significantly prolonged gestation (P<0.05) and α-BGT treatment reversed the prolonged interval (P<0.05). The cytokines all markedly elevated at 12h, but deceased after delivery (P<0.05). The IL-1β and TNF-α in serum were significantly increased in PTL group vs P group (P<0.05), and decreased after nicotine treatment (P<0.05). The cytokines IL-1β, IL-4, IL-6, IL-10 and TNF-α in myometrium increased as the same trend as in serum. Nicotine treatment also downregulated the expression of α7nAChR in pregnant tissue. We confirmed the increased inflammation in preterm birth. Nicotine was able to down-regulate the inflammatory mediates and prolong the pregnant duration in PTL model, which might be induced by activating α7nAChR through CAP. This study provides a novel evidence supporting the future development of therapeutic target for preterm birth.

GBP5 exacerbates rosacea-like skin inflammation by skewing macrophage polarization towards M1 phenotype through the NF-κB signalling pathway.

Rosacea is a chronic inflammatory skin disease with increased macrophage infiltration. However, the molecular mechanism remains unclear. To determine the significance of macrophage infiltration, and the correlation between Guanylate-binding protein 5 (GBP5) and polarization of macrophages in rosacea-like inflammation. Here we tested the hypothesis that Guanylate-binding protein 5 (GBP5) aggravates rosacea-like skin inflammation by promoting the polarization of the M1 macrophages through the NF-κB signalling pathway. We depleted macrophage by injecting clodronate-containing liposomes. We next explored the association between GBP5 and macrophage in rosacea tissue through transcriptome analysis and immunofluorescence analysis. We evaluated the severity of rosacea-like skin inflammation when BALB/c mice were injected with GBP5 siRNA intradermally daily for three consecutive days. At last, to study the causality of knocking down GBP5-blunted M1 macrophage polarization, THP-1 cell was treated with GBP5 siRNA. Macrophage depletion ameliorated rosacea-like skin inflammation in mice, implying the important role of macrophages in rosacea. Based on the transcriptome analysis, Guanylate-binding protein 5 (GBP5) was identified as hub gene that was associated with macrophage infiltration in rosacea. Next, we found that GBP5 expression was significantly upregulated in rosacea tissues and positively correlated with macrophage infiltration, the immunofluorescence analysis revealed the co-localization between GBP5 and macrophages. In vivo, silencing of GBP5 attenuated rosacea-like skin inflammation in the LL-37-induced mouse model and suppressed the expression of M1 signature genes such as IL-6, iNOS and TNF-a. In vitro, knocking down GBP5 significantly blunted the polarization of the M1 macrophages partly by repressing the activation of the NF-κB signalling pathways. Together, our study revealed the important role of macrophages in rosacea and identified GBP5 as a key regulator of rosacea by inducing M1 macrophage polarization via NF-κB signalling pathways.

Effects of Dietary Vegetable Oils Replacing Fish Oil on Fatty Acid Composition, Lipid Metabolism and Inflammatory Response in Adipose Tissue of Large Yellow Croaker (Larimichthys crocea)

The present study was conducted to investigate the effects of dietary vegetable oils (VOs) replacing fish oil (FO) on fatty acid composition, lipid metabolism and inflammatory response in adipose tissue (AT) of large yellow croaker (Larimichthys crocea). The initial body weight of a large yellow croaker was 10.07 ± 0.13 g. Three iso-nitrogenous and iso-lipidic diets were formulated by replacing FO with 0% (the control group), 100% soybean oil (SO) and 100% linseed oil (LO). Results showed that the contents of C18:2n-6 and C18:3n-3 were significantly increased in AT of fish fed the SO and LO diets compared with the FO diet, respectively. The proportion of n-6 polyunsaturated fatty acid (PUFA) was increased in SO and LO diets, while the proportions of saturated fatty acid and n-3 LC-PUFA were decreased. Moreover, dietary SO and LO significantly induced excess fat accumulation of AT by increasing the triglyceride content and the hypertrophy of adipocytes. Dietary SO and LO significantly increased lipogenesis-related gene expressions (dagt2, fabp10, srebp1, cebpα and pparγ), while decreasing the gene expression of lpl. Meanwhile, dietary SO increased the expression of genes related to fatty acid β-oxidation (cpt1 and aco), while LO showed no differences. Furthermore, dietary SO and LO increased the pro-inflammatory gene expressions and decreased the anti-inflammatory gene il10 expression. The phosphorylation levels of p38 MAPK and NF-κB were significantly upregulated by dietary SO and LO. In addition, there was a significant increase in macrophage infiltration and M1 polarization in AT of fish fed SO and LO diets. In conclusion, the present study revealed that dietary SO and LO replacing FO affected fatty acid composition and induced lipid dysmetabolism and inflammatory response in the adipose tissue of large yellow croaker.

RF04 | PSUN313 A Natural Antibody Against Oxidized Phospholipids Improves Glucose Metabolism in Aging Mice

Abstract Oxidative stress-induced lipid peroxidation generates oxidized phospholipids (OxPL), such as oxidized phosphatidylcholine, that are pro-inflammatory moieties present on oxidized low density lipoproteins and apoptotic cells. OxPL have been implicated in the pathogenesis of cardiovascular, neurological, autoimmune, liver, and lung diseases. It has been shown earlier that OxPL decrease bone formation. Natural antibodies (NAb) produced by B-1 lymphocytes, bind OxPL and prevent their inflammatory activity. The NAb E06 blocks oxidized phosphatidylcholine, and transgenic expression of a single chain (scFv) form of the antigen-binding domain of E06 IgM (E06-scFv) prevents many age-associated diseases, such as atherosclerosis, non-alcoholic steatohepatitis and age-related bone loss. OxPL are also implicated in the pathogenesis of the metabolic syndrome and diabetes by either causing insulin resistance, increasing macrophage infiltration and inflammation in white adipose tissue, decreasing insulin gene expression, and/or causing death of pancreatic beta cells through induction of oxidative stress and amyloid protein misfolding. Consistent with this evidence, NAb produced by B-1b lymphocytes are protective against obesity associated inflammation, glucose intolerance, and insulin resistance. In the work reported here, we have investigated the impact of oxidized phosphatidylcholine on glucose metabolism and age–related glucose intolerance. To this end, we aged chow-fed female and male C57BL/6 E06-scFv transgenic mice (and their WT littermates) up to 22 and 24 months. Both male and female E06-scFv transgenic mice accumulated less fat mass than WT littermates during aging, as determined by sequential body composition measurements by DXA. Intraperitoneal glucose tolerance test, performed at 10 and at 15 months of age, showed that glucose tolerance was greater in both male and female E06-ScFv transgenic mice than WT littermates and did not differ from the glucose tolerance of young mice. Insulin sensitivity, measured by insulin tolerance test, was increased in 4- and 10-month-old old transgenic females and in 15-month-old transgenic males. There was no difference in food consumption calculated over 5 days or the production of glucose after pyruvate infusion, indicating similar liver gluconeogenesis in both strains. Physical activity or energy expenditure, measured by indirect calorimetry in 11-month-old females, was indistinguishable between transgenic and WT mice. However, E06-scFv transgenic mice exhibited a significant increase in the respiratory exchange ratio, indicating that utilization of glucose was the main metabolic source under basal conditions. Collectively, these results show that blocking oxidized phosphatidylcholine improves age–related glucose intolerance in mice fed a normal diet; hence, OxPL are major culprits of the aging-associated glucose intolerance. Therefore, targeting OxPL with a neutralizing antibody represents a novel therapeutic intervention that may simultaneously ameliorate several age-associated diseases, including the metabolic syndrome and diabetes. Presentation: Saturday, June 11, 2022 1:42 p.m. - 1:47 p.m., Sunday, June 12, 2022 12:30 p.m. - 2:30 p.m.

OR30-5 Androgen-Regulated Secreted Factors Promote Tumorigenesis and Immune Suppression in Breast Cancer

Abstract Background Breast cancer (BC) is the most diagnosed cancer and the second-leading cause of cancer-associated death in women in the United States. BCs that express the estrogen and/or progesterone receptor (ER/PR) are treated with ER-targeting endocrine therapies that effectively reduce disease burden and extend lifespan. However, up to 50% of patients with ER+BCs will experience recurrence, often at a metastatic site, within 10 years of diagnosis. Novel targeted therapies are needed to treat both metastatic ER+BC resistant to current treatment strategies and chemoresistant ER-BCs.We identified chitinase 3–like-1 (CHI3L1/BRP-39/YKL-40) and prolactin inducible protein (PIP/GCDFP-15) as androgen receptor (AR)-regulated in BC. PIP is reported to be detectable in >90% of BCs, but its function in BC is not well-characterized. CHI3L1 is a glycosyl hydrolase family 18 protein member with reported roles in aging and numerous pathologies. During mammary gland involution, CHI3L1 contributes to a pro-tumorigenic wound-healing-like environment and increases macrophage infiltration. Further, CHI3L1 correlates with tumor-suppressive M2 macrophage infiltration in ER-BC. We previously reported that ER+ cells and patient-derived xenografts with activating mutations in the ESR1 gene encoding ER—a known mechanism of endocrine therapy resistance—had elevated AR and CHI3L1 gene and protein expression. Based on the above and our finding that metastatic BCs biopsies harboring ESR1 mutations exhibited increased AR expression, we hypothesized that AR regulation of CHI3L1 and PIP promote progression to metastatic disease in part through immune suppressive effects. Methods A ConTra(V3) transcription factor binding site analysis was performed on CHI3L1 and PIP promoters. CHI3L1 and PIP were measured via immunohistochemistry in xenograft tumors in mice treated with or without the androgen dihydrotestosterone (DHT). Immunoblotting, immunohistochemistry, and immunofluorescence approaches were also utilized to assess CHI3L1 protein expression in DHT-treated, tamoxifen resistant (TAMR), and long term E2 deprived (LTED) ER+BC cells. CIBERSORT analysis was conducted on the Firehouse Legacy TCGA dataset. Macrophage efferocytosis assays were performed on an IncuCyte Live Cell Imaging system. Results We identified highly conserved AR binding sites in the CHI3L1 and PIP promoters. CHI3L1 protein was elevated in TAMR and LTED BC cells, which was further elevated in BC cells with ESR1 mutations, as well as DHT-treated cells. Further, CHI3L1 and PIP were increased in xenograft tumors after DHT treatment. CIBERSORT analysis revealed that CHI3L1 and PIP high tumors had altered immune profiles, including differential macrophage levels. Finally, CHI3L1 and PIP treatment significantly reduced macrophage efferocytosis of BC cells (p ≤ 0.0001). Conclusions Our work suggests that AR-mediated regulation of CHI3L1 and PIP may alter immune cell infiltration/function in BC and may be important in endocrine therapy resistant ER+BCs. Further characterization and manipulation of these AR-regulated proteins is underway to test the potential to target and reverse their immune suppressive functions. Presentation: Tuesday, June 14, 2022 10:45 a.m. - 11:00 a.m.

A New Model of Acute Exacerbation of Experimental Pulmonary Fibrosis in Mice.

idiopathic pulmonary fibrosis (IPF) is the most severe form of fibrosing interstitial lung disease, characterized by progressive respiratory failure leading to death. IPF's natural history is heterogeneous, and its progression unpredictable. Most patients develop a progressive decline of respiratory function over years; some remain stable, but others present a fast-respiratory deterioration without identifiable cause, classified as acute exacerbation (AE). to develop and characterize an experimental mice model of lung fibrosis AE, mimicking IPF-AE at the functional, histopathological, cellular and molecular levels. we established in C57BL/6 male mice a chronic pulmonary fibrosis using a repetitive low-dose bleomycin (BLM) intratracheal (IT) instillation regimen (four instillations of BLM every 2 weeks), followed by two IT instillations of a simple or double-dose BLM challenge to induce AE. Clinical follow-up and histological and molecular analyses were done for fibrotic and inflammatory lung remodeling analysis. as compared with a low-dose BLM regimen, this AE model induced a late burst of animal mortality, worsened lung fibrosis and remodeling, and superadded histopathological features as observed in humans IPF-AE. This was associated with stronger inflammation, increased macrophage infiltration of lung tissue and increased levels of pro-inflammatory cytokines in lung homogenates. Finally, it induced in the remodeled lung a diffuse expression of hypoxia-inducible factor 1α, a hallmark of tissular hypoxia response and a major player in the progression of IPF. this new model is a promising model of AE in chronic pulmonary fibrosis that could be relevant to mimic IPF-AE in preclinical trials.

Development of a Prognostic Risk Model for Prostate Cancer Patients (Based on Patients with Gleason Score 9-10)

<h3>Purpose/Objective(s)</h3> Prostate cancer patients with Gleason scores (GS) 9-10 have high disease malignancy and poor prognosis. In this study, we will construct a prognostic risk model for prostate cancer patients starting from the molecular characteristics of patients with GS 9-10. <h3>Materials/Methods</h3> (1) Firstly, using the information of prostate cancer patients in the TCGA database (N=499), the differential genes were screened for specific screening criteria: prostate cancer tumor tissue, GS 9-10 score, and differential genes in patients with fast-progressing prostate cancer (Log2FC≥1, adjusted P-value <0.05), and these three components were taken as intersection. (2) Then, the GO, KEGG and GSEA enrichment analysis of the differential genes was carried to analyze the function of these genes. (3) And the analysis of protein interaction network for the differential molecules was carried in Metascape website. (4) We next brought the differential risk markers into lasso regression, calculating the risk model formula and risk scores. (5) Besides, we combined clinical factors (such as age, T, N stage, etc.) to establish a nomogram to predict the progress-free survival (PFS). (6) Finally, according to the risk formula, we analyzed the relationship between risk scores and immune infiltration of patients, providing clues for immunotherapy. <h3>Results</h3> (1) Differential gene intersections were obtained for three parts, and 83 genes was in total, further screening WASIR1, KPTAP5-1, TLX1, KIF4A, IQGAP3 as candidate molecules for risk markers. (2) The GO, KEGG and GSEA enrichment analysis showed that these genes were associated with biological processes such as cell cycle, steroid hormone metabolism, and hormone activity and so on, suggesting that these may be biological in prostate cancer patients with poor prognosis processes. (3) We constructed a risk formula for PFS of prostate cancer patients based on these factors as: Riskscore = (0.4851) *WASIR1+(0.4418) *KRTAP5-1+(0.6872) *TLX1+(0.1664) *KIF4A+(0.1699)* IQGAP3, which had high potency for predicting PFS, 10-year AUC=0.805, 95% CI (0.652-0.795); (4) Immune infiltration analysis showed a decrease in CD4+ and CD8+ T cells and an increase in macrophage infiltration in tumor tissues of high-risk patients. <h3>Conclusion</h3> Our study screened the risk markers and formula for predicting the prognosis of prostate cancer patients by TCGA database, which can calculate the risk score of patients according to the risk formula and provide some guidance for prognosis prediction and clinical treatment.

The Effects of Hyperglycemia on Early Endothelial Activation and the Initiation of Atherosclerosis

It is well established that patients with diabetes have an increased risk of developing atherosclerotic cardiovascular disease. The earliest detectable sign of atherosclerosis initiation is endothelial cell activation. Activated endothelial cells express adhesion proteins, P-selectin, E-selectin, vascular cell adhesion molecule-1, and intercellular adhesion molecule-1, which function to recruit monocytes to the subendothelial layer. This study examines the effect of hyperglycemia on endothelial cell activation and the initiation and progression of atherosclerosis. Invitro studies revealed that exposure of human aortic endothelial cells to elevated (30 mmol/L) glucose concentrations significantly increased the expression of P-selectin, E-selectin, and vascular cell adhesion molecule-1. Invivo studies showed that, before lesion development, 5-week-old hyperglycemic ApoE-/-Ins2+/akita mice had significantly increased expression of these adhesion proteins in the aortic sinus and increased macrophage infiltration, compared with normoglycemic ApoE-/- controls. At 25 weeks of age, ApoE-/-Ins2+/akita mice had significantly larger atherosclerotic plaques than ApoE-/- controls (0.022 ±0.004 versus 0.007±0.001 mm3; P<0.05). Similar endothelial activation was observed in heterozygous ApoE+/-Ins2+/akita mice; however, detectable atherosclerotic lesions did not develop in the absence of dyslipidemia. Lowering blood glucose levels (by 55%) using a sodium-glucose cotransporter 2 inhibitor reduced endothelial activation. Together, these findings support a causative role for hyperglycemia in atherogenesis and highlight the importance of blood glucose regulation in preventing atherosclerotic cardiovascular disease.

Visualization of macrophage inflammatory activity on visceral obesity in high-fat diet-induced obese mice by 18F-FDG PET/CT

Abstract Background Obesity induced inflamed visceral adipose tissue (VAT) secretes pro-inflammatory cytokines thereby promoting systemic inflammation and insulin resistance which further exacerbate obesity-related cardiovascular disease (CVD). Macrophages are the key players in the development of obesity-associated VAT inflammation. Extensive clinical studies have reported that 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) can be used to evaluate the macrophage inflammatory activity on VAT in human beings. However, due to difficulty in human VAT biopsy, pathologic correlations were lacking and there was a few study on preclinical animal models. Purpose Here, we investigated whether 18F-FDG PET/CT could reflect the macrophage inflammatory activity on VAT in high-fat diet-induced obese mice. Methods Obese animal models were induced by a high-fat diet (60% fat) for 20 weeks using the male C57BL/6 mice. Insulin tolerance test was performed to evaluate the status of insulin resistance and C-reactive protein (CRP) was measured to assess the status of systemic inflammation. All animals underwent 18F-FDG PET/CT before sacrifice. Macrophage inflammatory activity was evaluated using the maximum standardized uptake value (SUVmax). Flow cytometry-, histological-, and molecular analyses were performed on harvested VAT. Results All obese animals showed insulin resistance which resembled the human metabolic syndrome, a key pathophysiological process that contributes to increase CVD risk. VAT SUVmax was increased in obese mice and significantly correlated with the levels of CRP. Furthermore, VAT from obese mice showed increased macrophage infiltration, compared to normal mice. Conclusions 18F-FDG PET/CT could visualize and evaluate the macrophage inflammatory activity on obesity-driven inflamed VAT in obese mice model. Our preclinical study strongly supports the clinical application of 18F-FDG PET/CT in the assessment of VAT inflammation to patients who are vulnerable to CVD. Funding Acknowledgement Type of funding sources: None.

Macrophage Infiltration Initiates RIP3/MLKL-Dependent Necroptosis in Paclitaxel-Induced Neuropathic Pain.

Paclitaxel (PTX) is a commonly used antitumor drug. Approximately 80% of all patients receiving PTX chemotherapy develop chemotherapy-induced peripheral neuropathy (CIPN), limiting the use of PTX. Moreover, CIPN responds poorly to conventional analgesics. Experimental evidence suggests that the neuroinflammatory response plays an essential role in paclitaxel-induced peripheral neuropathy (PIPN). Previous studies have confirmed that dorsal root ganglion (DRG) neuron necroptosis and accompanying inflammation are linked with PIPN; however, the potential upstream regulatory mechanisms remain unclear. Preclinical studies have also established that macrophage infiltration in the DRG is associated with PIPN. TNF-α released by activated macrophages is the primary regulatory signal of necroptosis. In this study, we established a rat model of PIPN via quartic PTX administration (accumulated dose: 8 mg/kg, i.p.). The regulatory effect of macrophage infiltration on necroptosis in PIPN was observed using a macrophage scavenging agent (clodronate disodium). The results showed that PTX increased macrophage infiltration and the levels of TNF-α and IL-1β in the DRG. PTX also upregulated the levels of necroptosis-related proteins, including receptor-interacting protein kinase (RIP3) and mixed-lineage kinase domain-like protein (MLKL) in DRG neurons and promoted MLKL phosphorylation, resulting in neuronal necrosis and hyperalgesia. In contrast, clodronate disodium effectively removed macrophages, reduced the levels of RIP3, MLKL, and pMLKL, and decreased the number of necrotic cells in the DRG of PIPN rats, alleviating the behavioral pain abnormalities. These results suggest that PTX promotes macrophage infiltration, which results in the release of TNF-α and IL-1β in the DRG and the initiation of neuronal necroptosis via the RIP3/MLKL pathway, ultimately leading to neuropathic pain.

Thalidomide modulates renal inflammation induced by brain death experimental model

BackgroundBrain death (BD) is characterized by a complex inflammatory response, resulting in dysfunction of potentially transplantable organs. This process is modulated by cytokines, which amplify graft immunogenicity. We have investigated the inflammatory response in an animal model of BD and analyzed the effects of thalidomide, a drug with powerful immunomodulatory properties. MethodsBD was induced in male Lewis rats. We studied three groups: Control (sham-operated rats) (n = 6), BD (rats subjected to brain death) (n = 6) and BD + Thalid (BD rats treated with one dose of thalidomide (200 mg/Kg), administered by gavage) (n = 6). Six hours after BD, serum levels of urea and creatinine, as well as systemic and renal tissue protein levels of TNF-α and IL-6, were analyzed. We also determined the mRNA expression of ET-1, and macrophage infiltration by immunohistochemistry. ResultsBD induced a striking inflammatory status, demonstrated by a significant increase of plasma cytokines: TNF-α (2.8 ± 4.3 pg/mL [BD] vs. 9.4 ± 2.8 pg/mL [Control]), and IL-6 (6219.5 ± 1380.6 pg/mL [BD] vs. 1854.7 ± 822.6 pg/mL [Control]), and in the renal tissue: TNF-α (2.5 ± 0.3 relative expression [BD] vs. 1.0 ± 0.4 relative expression [Control]; p < 0.05), and IL-6 (4.0 ± 0.4 relative expression [BD] vs. 1.0 ± 0.3 relative expression [Control]; p < 0.05). Moreover, BD increased macrophages infiltration (2.47 ± 0.07 cells/field [BD] vs. 1.20 ± 0.05 cells/field [Control]; p < 0.05), and ET-1 gene expression (2.5 ± 0.3 relative expression [BD] vs. 1.0 ± 0.2 relative expression [Control]; p < 0.05). In addition, we have observed deterioration in renal function, characterized by an increase of urea (194.7 ± 25.0 mg/dL [BD] vs. 108.0 ± 14.2 mg/dL [Control]; p < 0.05) and creatinine (1.4 ± 0.04 mg/dL [BD] vs. 1.0 ± 0.07 mg/dL [Control]; p < 0.05) levels. Thalidomide administration significantly reduced plasma cytokines: TNF-α (5.1 ± 1.4 pg/mL [BD + Thalid] vs. BD; p < 0.05), and IL-6 (1056.5 ± 488.3 pg/mL [BD + Thalid] vs. BD; p < 0.05), as well as in the renal tissue: TNF-α (1.5 ± 0.2 relative expression [BD + Thalid] vs. BD; p < 0.05), and IL-6 (2.1 ± 0.3 relative expression [BD + Thalid] vs. BD; p < 0.05). Thalidomide treatment also induced a significant decrease in the expression of ET-1 (1.4 ± 0.3 relative expression [BD + Thalid] vs. BD; p < 0.05), and macrophages infiltration (1.17 ± 0.06 cells/field [BD + Thalid] vs. BD; p < 0.05). Also thalidomide prevented kidney function failure by reduced urea (148.3 ± 4.4 mg/dL [BD + Thalid] vs. BD; p < 0.05), and creatinine (1.1 ± 0.14 mg/dL [BD + Thalid] vs. BD; p < 0.05). ConclusionsThe immunomodulatory properties of thalidomide were effective in decreasing systemic and local immunologic response, leading to diminished renal damage, as reflected in the decrease of urea and creatinine levels. These results suggest that use of thalidomide may represent a potential strategy for treating in BD kidney organ donors.

The Nonproteolytic Intracellular Domain of Membrane-Type 1 Matrix Metalloproteinase Coordinately Modulates Abdominal Aortic Aneurysm and Atherosclerosis in Mice-Brief Report.

MT1-MMP (membrane-type 1 matrix metalloproteinase, MMP-14) is a transmembrane-anchored protein with an extracellular proteinase domain and a cytoplasmic tail devoid of proteolytic functions but capable of mediating intracellular signaling that regulates tissue homeostasis. MT1-MMP extracellular proteolytic activity has been shown to regulate pathological remodeling in aortic aneurysm and atherosclerosis. However, the role of the nonproteolytic intracellular domain of MT1-MMP in vascular remodeling in abdominal aortic aneurysms (AAA) is unknown. We generated a mutant mouse that harbors a point mutation (Y573D) in the MT1-MMP cytoplasmic domain that abrogates the MT1-MMP signaling function without affecting its proteolytic activity. These mice and their control wild-type littermates were subjected to experimental AAA modeled by angiotensin II infusion combined with PCSK9 (proprotein convertase subtilisin/kexin type 9) overexpression and high-cholesterol feeding. The mutant mice developed more severe AAA than the control mice, with concomitant generation of intraaneurysmal atherosclerotic lesions and dramatically increased macrophage infiltration and elastin degradation. Aortic lesion-associated and bone marrow-derived macrophages from the mutant mice exhibited an enhanced inflammatory state and expressed elevated levels of proinflammatory Netrin-1, a protein previously demonstrated to promote both atherosclerosis and AAA. Our findings show that the cytoplasmic domain of MT1-MMP safeguards from AAA and atherosclerotic plaque development through a proteolysis-independent signaling mechanism associated with Netrin-1 expression. This unexpected function of MT1-MMP unveils a novel mechanism of synchronous onset of AAA and atherogenesis and highlights its importance in the control of vascular wall homeostasis.

Esaxerenone inhibits the macrophage-to-myofibroblast transition through mineralocorticoid receptor/TGF-β1 pathway in mice induced with aldosterone.

Renal fibrosis is the inevitable pathway of the progression of chronic kidney disease to end-stage renal disease, which manifests as progressive glomerulosclerosis and renal interstitial fibrosis. In a previous study, we observed severe interstitial fibrosis in the contralateral kidneys of 6-month unilateral ureteral obstruction (UUO) rats, which was accompanied by increased macrophage infiltration and phenotypic transformation; after eplerenone administration, these effects were reduced. Therefore, we hypothesized that this effect was closely related to mineralocorticoid receptor (MR) activation induced by the increased aldosterone (ALD) level. In this study, we used uninephrectomy plus continuous aldosterone infusion in mice to observe whether aldosterone induced macrophage-to-myofibroblast transition (MMT) and renal fibrosis and investigated the signaling pathways. Notably, aldosterone induced predominantly M1 macrophage-to-myofibroblast transition by activating MR and upregulating TGF-β1 expression, which promoted renal fibrosis. These effects were antagonized by the MR blocker esaxerenone. These findings suggest that targeting the MR/TGF-β1 pathway may be an effective therapeutic strategy for renal fibrosis.

Maternal fructose intake during pregnancy and lactation: Later effects on renal function.

Excessive fructose consumption has been associated with hypertension and metabolic disorders and can alter physiological adaptations during pregnancy, with long‐term detrimental consequences. This study evaluated in post‐weaning mothers the effects of increased fructose consumption during pregnancy and lactation on blood pressure and renal function. Female Wistar rats were assigned to one of four experimental groups: non‐pregnant control (NPC); pregnant control (PC); non‐pregnant fructose (NPF), and pregnant fructose (PF). Control rats had free access to food and water, while the fructose groups had free access to food and to a 20% fructose solution, over the time period of the experiment. The systolic BP and renal function parameters were measured at the end of the experimental period, one week after weaning (28 days after delivery). The results were presented as means ± standard error. Higher values of BP were observed in both pregnant and non‐pregnant rats treated with fructose compared to control. Creatinine clearance was reduced only in the PF group; however, both the PF and NPF groups had reduced Na+ and K+ excretions. In the PF group, there was also glomerular enlargement and changes in the media/lumen (M/L) ratio of interlobular arteries. Additionally, the PF group showed increased macrophage infiltration and expression of alpha‐SM‐actin and reduced expression of nitric‐oxide‐synthase endothelial in renal tissue. These findings suggest that the association of high fructose intake with pregnancy aggravated kidney changes that persisted for up to four weeks after delivery, which may represent a risk factor for maternal health.