Pro-inflammatory Macrophages Research Articles

Myeloid Drp1 deficiency limits revascularization in ischemic muscles via inflammatory macrophage polarization and metabolic reprograming.

Macrophage plays a crucial role in promoting perfusion recovery and revascularization after ischemia through anti-inflammatory polarization, a process essential for the treatment of peripheral arterial disease (PAD). Mitochondrial dynamics, particularly regulated by the fission protein DRP1, are closely linked to macrophage metabolism and inflammation. However, the role of DRP1 in reparative neovascularization remains unexplored. Here we show that DRP1 expression was increased in F4/80+ macrophages within ischemic muscle at day 3 after hindlimb ischemia (HLI), an animal model of PAD. Mice lacking Drp1 in myeloid cells exhibited impaired limb perfusion recovery, angiogenesis and muscle regeneration post-HLI. These effects were associated with increased pro-inflammatory M1-like macrophages, p-NFkB and TNFα, and reduced anti-inflammatory M2-like macrophages and p-AMPK in ischemic muscle of myeloid Drp1-/- mice. In vitro, Drp1-deficient macrophages under hypoxia serum starvation (HSS), an in vitro PAD model, demonstrated enhanced glycolysis via reducing p-AMPK as well as mitochondrial dysfunction, and excessive mitochondrial ROS production, resulting in increased pro-inflammatory M1-gene and reduced anti-inflammatory M2-gene expression. Conditioned media from HSS-treated Drp1-/- macrophages exhibited increased pro-inflammatory cytokine secretion, leading to suppressed angiogenesis in endothelial cells. Thus, macrophage DRP1 deficiency under ischemia drives pro-inflammatory metabolic reprogramming and macrophage polarization, limiting revascularization in experimental PAD.

Mesenchymal precursor cells reduce mortality and major morbidity in ischaemic heart failure with inflammation: DREAM-HF.

Progressive heart failure with reduced ejection fraction (HFrEF) is adversely affected by alterations in the myocardial balance between bone marrow-derived pro-inflammatory cardiac macrophages and embryo-derived reparative cardiac resident macrophages. Mesenchymal precursor cells (MPCs) may restore this balance and improve clinical outcomes when inflammation is present. The purpose was to (i) identify risk factors for cardiovascular death (CVD) in control patients with HFrEF in the DREAM-HF trial, and (ii) determine if MPCs improve major clinical outcomes (CVD, myocardial infarction [MI], stroke) in high-risk patients with ischaemic HFrEF and inflammation. Cause-specific regression analyses were used to identify CVD risk factors in DREAM-HF control patients. Aalen-Johansen cumulative incidence curves were used to examine CVD, 2-point major adverse cardiovascular events (MACE) (MI or stroke), and 3-point MACE (CVD or MI or stroke) by treatment group in ischaemic vs non-ischaemic HFrEF and in patients with or without baseline inflammation. In control DREAM-HF patients, factors portending the greatest risk for CVD were inflammation (baseline plasma high-sensitivity C-reactive protein ≥2 mg/L; p = 0.003) and ischaemic HFrEF aetiology (p = 0.097), with increased CVD risk of 61% and 38%, respectively. Over 30-month mean follow-up, MPCs reduced 2-point and 3-point MACE by 88% (p = 0.005) and 52% (p = 0.018), respectively, in patients with ischaemic HFrEF and inflammation compared to controls. Ischaemic aetiology and inflammation were identified as major risk factors for MACE in control DREAM-HF patients. A single intramyocardial MPC administration produced the most significant, sustained reduction in 2-point and 3-point MACE in patients with ischaemic HFrEF and inflammation.

Peripheral nerve-derived CSF1 induces BMP2 expression in macrophages to promote nerve regeneration and wound healing

The precise mechanisms regulating inflammatory and prorepair macrophages have not been fully elucidated, despite the pivotal role played by innate immunity in wound healing. We first employed a denervation wound model to validate the crosstalk between neurons and macrophages. Compared to normal wound healing, the denervation wound healing process involved fewer macrophages, decreased angiogenesis, and delayed wound healing. Consistent with the results of the scRNA-seq libraries, the number of early-phase wound proinflammatory and late-phase wound prorepair macrophages were decreased during the denervation wound healing process. We profiled early-phase and late-phase skin wounds in mice at the transcriptional and functional levels and compared them to those of normal wounds. We revealed a neuroimmune regulatory pathway driven by peripheral nerve-derived CSF1 that induces BMP2 expression in prorepair macrophages and enhances nerve regeneration. Crosstalk between neurons and macrophages facilitates the healing process of wounds and provides a potential strategy for wound healing therapy.

Lipoxin A4 improves cardiac remodeling and function in diabetes-associated cardiac dysfunction

BackgroundDiabetic heart disease may eventually lead to heart failure, a leading cause of mortality in diabetic individuals. The lack of effective treatments for diabetes-induced heart failure may result from a failure to address the underlying pathological processes, including chronic, low-grade inflammation. Previous studies have reported that lipoxin A4 (LXA4), known to promote resolution of inflammation, attenuates diabetes-induced atherosclerosis, but its impact on diabetic hearts has not been sought. Thus, we aimed to determine whether LXA4 therapeutic treatment attenuates diabetes-induced cardiac pathology.MethodsSix-week-old male apolipoprotein E-deficient (ApoE−/−) mice were followed for 16 weeks after injection of streptozotocin (STZ, 55 mg/kg/day, i.p. for 5 days) to induce type-1 diabetes (T1DM). Treatment with LXA4 (5 μg/kg, i.p.) or vehicle (0.02% ethanol, i.p.) was administered twice weekly for the final 6 weeks. One week before endpoint, echocardiography was performed within a subset of mice from each group. At the end of the study, mice were euthanized with sodium pentobarbital (100 mg/kg i.p.) and hearts were collected for ex vivo analysis, including histological assessment, gene expression profiling by real-time PCR and protein level measurement by western blot.ResultsAs expected diabetic mice showed a significant elevation in plasma glycated hemoglobin (HbA1c) and glucose levels, along with reduced body weight. Vehicle-treated diabetic mice exhibited increased cardiac inflammation, macrophage content, and an elevated ratio of M1-like to M2-like macrophage markers. In addition, myocardial fibrosis, cardiomyocytes apoptosis and hypertrophy (at the genetic level) were evident, with echocardiography revealing early signs of left ventricular (LV) diastolic dysfunction. Treatment with LXA4 ameliorated diabetes-induced cardiac inflammation, pro-inflammatory macrophage polarization and cardiac remodeling (especially myocardial fibrosis and cardiomyocytes apoptosis), with ultimate improvement in cardiac function. Of note, this improvement was independent of glucose control.ConclusionsThese findings demonstrated that LXA4 treatment attenuated the extent of cardiac inflammation in diabetic hearts, resulting in limited cardiac remodeling and improved LV diastolic function. This supports further exploration of LXA4-based therapy for the management of diabetic heart disease. The recent development of stable LXA4 mimetics holds potential as a novel strategy to treat cardiac dysfunction in diabetes, paving the way for innovative and more effective therapeutic strategies.Graphical

Therapeutic effects of extracellular vesicles derived from mesenchymal stem cells primed with disease-conditioned-immune cells in systemic lupus erythematosus

BackgroundSystemic lupus erythematosus (SLE) is an incurable chronic autoimmune disease of unknown etiology. Therefore, the development of new treatments is urgently needed. This study aimed to investigate the therapeutic effects of extracellular vesicles (EV) derived from immortalized mesenchymal stem cells (iMSCs) primed with conditioned media obtained from disease-conditioned immune cells (CM-EV) and iMSC-derived EV (ASC-EV) in a murine model of SLE.MethodsFemale NZB/W F1 mice were divided into the control (C, n = 15), ASC-EV (E, n = 15), and CM-EV (CM, n = 15) groups. Mice in the C, E, and CM groups were intravenously administered saline, ASC-EV, and CM-EV, respectively, once weekly from 6 to 42 weeks of age.ResultsCompared to the ASC-EV, the CM-EV showed a significant increase in TGF-β1 production and miR-155-5p and miR-142-3p expression. CM-EV treatment increased survival, decreased anti-dsDNA antibody levels, and ameliorated renal histopathology. Although ASC-EV treatment significantly reduced the incidence of severe proteinuria and improved renal histopathology, it did not significantly improve survival rate.ASC-EV or CM-EV treatment significantly decreased the proportion of pro-inflammatory macrophages (CD11c + CD206-; M1) and M1:M2 ratio. Additionally, CM-EV treatment significantly increased the expression of anti-inflammatory macrophages (CD11c-CD206 + ; M2). Moreover, CM-EV treatment significantly decreased the expression of lupus-specific miRNAs (miR-182-5p and miR-183-5p) in the spleen.ConclusionsEV derived from iMSCs primed with conditioned media obtained from disease-conditioned immune cells exert immunomodulatory effects and ameliorate SLE in a murine model.

The HDAC6 inhibitor AVS100 (SS208) induces a pro-inflammatory tumor microenvironment and potentiates immunotherapy.

Histone deacetylase 6 (HDAC6) inhibition is associated with an increased pro-inflammatory tumor microenvironment and antitumoral immune responses. Here, we show that the HDAC6 inhibitor AVS100 (SS208) had an antitumoral effect in SM1 melanoma and CT26 colon cancer models and increased the efficacy of anti-programmed cell death protein 1 treatment, leading to complete remission in melanoma and increased response in colon cancer. AVS100 treatment increased pro-inflammatory tumor-infiltrating macrophages and CD8 effector T cells with an inflammatory and T cell effector gene signature. Acquired T cell immunity and long-term protection were evidenced as increased immunodominant T cell clones after AVS100 treatment. Last, AVS100 showed no mutagenicity, toxicity, or adverse effects in preclinical good laboratory practice studies, part of the package that has led to US Food and Drug Administration clearance of an investigational new drug application for initiating clinical trials. This would be a first-in-human combination therapy of pembrolizumab with HDAC6 inhibition for locally advanced or metastatic solid tumors.

Regulation of Colonic Inflammation and Macrophage Homeostasis of IFN-γ-Primed Canine AMSCs in Experimental Colitis in Mice.

Mesenchymal stem cells (MSCs) have shown potential in treating immune-mediated diseases due to their immunomodulatory properties, which can be enhanced by priming with inflammatory cytokines like interferon-gamma (IFN-γ). This study evaluates the therapeutic effects of IFN-γ-primed canine adipose tissue-derived MSCs (AMSCs) in a mouse model of inflammatory bowel disease (IBD). Canine AMSCs were primed with 50 ng/mL recombinant canine IFN-γ for 48 h, and the effects were compared to those seen in naïve (unprimed) AMSCs. IBD was induced in mice using dextran sodium sulfate (DSS), and AMSCs were injected intraperitoneally on days 1 and 3. The mice treated with IFN-γ-primed AMSCs showed improved clinical outcomes, including a reduced disease activity index (DAI), less body weight loss, and longer colon length compared to the mice treated with naïve AMSCs. A histological analysis revealed less damage to the intestinal structures and reduced inflammatory cell infiltration. IFN-γ priming led to a shift in the immune cell balance in the gut, decreasing pro-inflammatory macrophages (Ly6Chi) and increasing anti-inflammatory macrophages (Ly6Clo/MHC-IIhi). This was associated with the reduced expression of inflammatory cytokine genes (Il-1β, Il-6, and Il-18) and increased expression of the intestinal stem cell marker Lgr5. These findings suggest that IFN-γ-primed AMSCs offer enhanced therapeutic potential for treating CE in veterinary medicine.

Abstract 4137337: Targeting Macrophage NCOR1 to Alleviate Inflammation in Heart Failure with Preserved Ejection Fraction

Background: Inflammatory response is a key player in heart failure with preserved ejection fraction, however the underlying mechanisms remain unclear. Recent evidence indicates that macrophage inflammation driven by the transcriptional coregulatory protein NCOR1 could play a pivotal role in disease states. Hypothesis: NCOR1 orchestrates macrophage inflammation and cardiac dysfunction in HFpEF. Methods: HFpEF was induced in mice using a validated model combining high-fat diet and L-NAME for 15 weeks. Cardiac function was assessed using high-resolution ultrasound imaging and LV samples were used to study macrophage polarization and inflammation by FACS. We generated myeloid-specific NCOR1-KO mice to investigate the in vivo effects of macrophage NCOR1 depletion on HFpEF. In vitro experiments included RAW 264.7 cells polarization and the assessment of macrophage phenotype switching in the presence or the absence of NCOR1. To study the crosstalk of macrophages with the surrounding cardiac cells, cardiomyocytes (H9c2) and endothelial cells (HAECS) were exposed to conditioned media from cultured RAW. Results: The expression of macrophage markers in human LV specimens showed an increase in pro-inflammatory macrophages (M1) and a decrease in regulatory macrophages (M2) as compared to age-matched control mice. HFpEF mice showed increased expression of vascular adhesion molecules (ICAM1, ICAM2, E-selectin) and a significant recruitment of M1 macrophages as proved by qPCR, WB, and flow cytometry analysis. Of interest, diastolic dysfunction - assessed by E/A ratio and isovolumic relaxation time (IVRT) – and lung congestion were significantly reduced in mice with macrophage NCOR1 deletion as compared to WT littermates, while exercise tolerance was significantly improved. These findings were associated with a reduction of myocardial inflammation (TNF-a, IL6, IL-1b) in Ncor1-KO mice. In vitro assays showed that stimulation of macrophages with PA induced M1 type switch and increased NCOR1, TNF-a, IL-6, and IL-1b levels, whereas NCOR1 depletion prevented detrimental changes of macrophage conditional medium (Fig.1). Conclusion: Targeting macrophage NCOR1 could represent a promising approach to blunt myocardial inflammation in HFpEF.

Abstract 4137935: Adipogenesis in Bone Marrow Niche under Cardiac Stress Worsens Cardiac Function

Background: We have recently reported that repetitive cardiac decompensation with multimorbidity often experienced by patients with heart failure (HF) is attributed to epigenetic modifications of hematopoietic stem cells (HSCs) in the bone marrow (BM). HF reprogrammed HSCs differentiation and altered tissue macrophage homeostasis. These findings demonstrate that the BM can carry an innate immune memory of cardiac stress that may exacerbate HF and predispose other organs to pathology. Aims: Because the stemness of HSCs is mainly regulated by mesenchymal stromal cells (MSCs) in the BM niche, we investigated phenotypic alterations of MSCs under cardiac stress. Methods&Results: Transcriptome analysis of MSCs showed preferential differentiation toward adipocytes in murine pressure overload models. In vitro assays and histological BM sections also support this finding. Furthermore, single-cell RNA sequencing of MSCs demonstrated that the percentage of adipocyte-primed MSCs increased in proportion to the severity of cardiac dysfunction, and also correlated with the frequency of myeloid-lineage progenitor cells. To investigate the influence of adipo-lineage MSCs on HSCs, we conducted BM transplantation supplemented with MSCs from control or HF mice. Recipient mice transplanted with HF-MSCs showed significant increases in myeloid-biased multipotent progenitors in BM and myeloid cells in peripheral blood. Additionally, the number of proinflammatory cardiac macrophages was significantly increased in the HF-MSCs group, promoting cardiac fibrosis and dysfunction. Conclusions: Our results demonstrated that the BM niche could perceive cardiac stress in the form of adipocytic skewing of MSCs in the setting of HF, which changed the differentiation behavior in HSCs and ultimately led to further deterioration of cardiac function through the impaired differentiation of circulating monocytes into cardiac macrophages. Therefore, suppressing the adipocytic differentiation of MSCs could have a novel therapeutic potential to avoid repeated HF events.

12-Lipoxygenase inhibition delays onset of autoimmune diabetes in human gene replacement mice.

Type 1 diabetes (T1D) is characterized by the autoimmune destruction of insulin-producing beta cells and involves an interplay between beta cells and cells of the innate and adaptive immune systems. We investigated the therapeutic potential of targeting 12-lipoxygenase (12-LOX), an enzyme implicated in inflammatory pathways in beta cells and macrophages, using a mouse model in which the endogenous mouse Alox15 gene is replaced by the human ALOX12 gene. Our finding demonstrated that VLX-1005, a potent 12-LOX inhibitor, effectively delayed the onset of autoimmune diabetes in human gene replacement non-obese diabetic mice. By spatial proteomics analysis, VLX-1005 treatment resulted in marked reductions in infiltrating T and B cells and macrophages with accompanying increases in immune checkpoint molecule PD-L1, suggesting a shift towards an immune-suppressive microenvironment. RNA sequencing analysis of isolated islets and polarized proinflammatory macrophages revealed significant alteration of cytokine-responsive pathways and a reduction in interferon response after VLX-1005 treatment. Our studies demonstrated that the ALOX12 human replacement gene mouse provides a platform for the preclinical evaluation of LOX inhibitors and supports VLX-1005 as an inhibitor of human 12-LOX that engages the enzymatic target and alters the inflammatory phenotypes of islets and macrophages to promote the delay of autoimmune diabetes.

Macrophage-Specific Lactate Dehydrogenase Expression Modulates Inflammatory Function In Vitro.

In acute kidney injury, macrophages play a major role in regulating inflammation. Classically activated macrophages (M1) undergo drastic metabolic reprogramming during their differentiation and upregulate the aerobic glycolysis pathway to fulfill their pro-inflammatory functions. NAD+ regeneration is crucial for the maintenance of glycolysis and the most direct pathway by which this occurs is via the fermentation of pyruvate to lactate, catalyzed by lactate dehydrogenase A (LDHA). Our previous study determined that LDHA is predominantly expressed in the proximal segments of the nephron in the mouse kidney and increases with hypoxia. This study investigates the potential of LDHA as a therapeutic target for inflammation by exploring its role in macrophage function in vitro. Bone-marrow-derived macrophages (BMDMs) were isolated from myeloid-specific LDHA knockout mice derived from crossbreeding LysM-Cre transgenic mice and LDHA floxed mice. RNA sequencing and LC-MS/MS metabolomics analyses were used in this study to determine the effect of LDHA deletion on BMDM following stimulation with IFN-γ. LDHA deletion in IFN-γ BMDMs resulted in a significant alteration of the macrophage activation and functional pathways, and change in glycolytic, cytokine, and chemokine gene expression. Metabolite concentrations associated with pro-inflammatory macrophage profiles were diminished while anti-inflammatory-associated ones were increased in LDHA KO BMDMs. Glutamate and amino sugars metabolic pathways were significantly affected by the LDHA deletion. A combined muti-omics analysis highlighted changes in Rap1 signaling, cytokine-cytokine receptor interaction, focal adhesion, and MAPK signaling metabolism pathways. Deletion of LDHA in macrophages results in a notable reduction in the pro-inflammatory profile and concurrent upregulation of anti-inflammatory pathways. These findings suggest that LDHA could serve as a promising therapeutic target for inflammation, a key contributor to the pathogenesis of acute kidney injury.

DNAR-10. PHASE I CLINICAL TRIAL OF PEPOSERTIB PLUS RADIOTHERAPY IN ADULTS WITH NEWLY-DIAGNOSED MGMT-UNMETHYLATED GLIOBLASTOMA

Abstract BACKGROUND DNA-dependent protein kinase (DNA-PK) is an attractive target in GBM because it promotes unwanted DNA repair and renders cancer cells less vulnerable to DNA damaging agents, such as radiotherapy (RT). Peposertib, a small molecule inhibitor of DNA-PK, has demonstrated pre-clinical efficacy in sensitizing GBM to RT, resulting in tumor regression. METHODS 21 patients with newly-diagnosed MGMT-unmethylated GBM received peposertib plus 6-weeks of RT to determine the maximum-tolerated dose (MTD) based on the Bayesian Optimal Interval design. The dose-limiting toxicity (DLT) period was 10-weeks. Patients received at least 6-cycles of adjuvant temozolomide (NCT04555577). Single-nuclei RNA-sequencing (snRNA-Seq) and spatial transcriptomics (Visium, 10x Genomics) were performed on matched pair primary-recurrent tumors and controls, incorporating tumor cell state and cell type definitions by automated cluster classification and differential expression of marker genes. RESULTS The MTD of peposertib in combination with RT was 300mg per RT fraction day. One DLT (G3 radiation necrosis @300mg) was observed. After a median follow-up of 15.4 months (interquartile-range 8.9-18.5), mPFS was 10.8 months (95%CI 8.33-NR) and mOS was 22.9 months (95%CI 16-NR). 6/21 (29%) patients have undergone re-resection to date. snRNA-Seq on 102,709 cells from 12 primary and 3 recurrent tumors revealed that pre-treatment tumor cell states were progenitor-like, while treatment with peposertib plus RT was associated with differentiated and inflammatory malignant cell states, along with macrophage infiltration. Spatial transcriptomics of 8 matched primary-recurrent tumors (20,793 transcriptomes) confirmed malignant cell differentiation and enrichment of pro-inflammatory macrophages after inhibition of DNA-PK. 5 patients will be enrolled into a window-of-opportunity expansion cohort to evaluate intratumoral drug concentration. CONCLUSION The combination of peposertib and intracranial RT was safe. Survival data for this MGMT-unmethylated GBM population was promising. Single nuclei and spatial transcriptomic analyses revealed enrichment of pro-inflammatory macrophages in the tumor microenvironmentafter DNA-PK inhibition. The study was supported by EMD-Serono (CrossRef Funder ID: 10.13039/100004755).

Alveolar and Bone Marrow-derived Macrophages Differ in Metabolism and Glutamine Utilization.

Changes in metabolic activity are key regulators of macrophage activity. Pro-inflammatory macrophages upregulate glycolysis, which promotes an inflammatory phenotype, whereas pro-repair macrophages rely upon oxidative metabolism and glutaminolysis to support their activity. Work to understand how metabolism regulates macrophage phenotype has been done primarily in macrophage cell lines and bone marrow-derived macrophages (BMDM). Our study sought to understand changes in metabolic activity of murine tissue-resident alveolar macrophages (AM) in response to LPS stimulation and to contrast them to BMDM. These studies also determined the contribution of glutamine metabolism using the glutamine inhibitor, DON. We found that compared to BMDM, AM have higher rates of oxygen consumption and contain a higher concentration of intracellular metabolites involved in fatty acid oxidation. In response to LPS, BMDM but not AM increased rates of glycolysis. Inhibition of glutamine metabolism using DON altered the metabolic activity of AM but not BMDM. Within AM, glutamine inhibition led to increases in intracellular metabolites involved in glycolysis, the TCA cycle, fatty acid oxidation, and amino acid metabolism. Glutamine inhibition also altered the metabolic response to LPS within AM but not BMDM. Our data reveal striking differences in the metabolic activity of AM and BMDM.

The macrophage migration inhibitory factor/CD74 axis in traumatic spinal cord injury: lessons learned from animal and human studies.

Traumatic spinal cord injury (SCI) is a severe condition leading to long-term impairment of motor, sensory, and autonomic functions. Following the initial injury, a series of additional events is initiated further damaging the spinal cord. During this secondary injury phase, both an inflammatory and immune modulatory response are triggered that have damaging and anti-inflammatory properties, respectively. The proinflammatory cytokine macrophage migration inhibitory factor (MIF) and its receptor CD74 have been extensively studied in traumatic SCI. MIF expression is increased in spinal cord tissue after experimental SCI, mainly in astrocytes and microglia, as well as in the plasma of SCI patients. Functionally, MIF and CD74 were shown to regulate astrocyte viability, proliferation and cholesterol metabolism, microglia migration, and neuronal viability. Moreover, inhibition of the MIF/CD74 axis improved the functional recovery of SCI animals. We provide a detailed overview of studies analyzing the role of MIF and CD74 in traumatic SCI. We describe results from animal studies, using rat and mouse models for SCI, and human studies. Furthermore, we propose a new path for investigation, focused on B cells, that might lead to a better understanding of how MIF and CD74 contribute to the secondary injury cascade following traumatic SCI.

Evaluation of the Effectiveness of Active Vitamin D Use in Experimental Rat Lymphedema Model.

Background and Objectives: Lymphedema is a progressive, chronic condition. Traumatic damage to the lymphatics, removal of lymph nodes, and/or radiation are the major causes of fibrosis and a subsequent pathological cascade. Macrophages play a crucial role in wound healing, with M1 macrophages known for their pro-inflammatory effects and M2 macrophages recognized for their anti-inflammatory effects, including improved angiogenesis, lymph angiogenesis, and tissue healing. This study aims to assess the use of calcitriol to alter the M2/M1 macrophage balance, reduce tissue fibrosis in a lymphedema model, promote new micro-lymphatic vessel formation, and evaluate the benefits of active vitamin D. Material and Methods: Forty-five rats were randomly divided into three groups: control surgery (group A), surgery with preoperative-postoperative calcitriol (group B), and postoperative calcitriol (group C). One week after the surgical ablation a total dose of 20 Gy radiation therapy was administered to the operated groin region. Micro-computed tomography was used for limb volume calculation, fluorescence lymphatic imaging was used to assess the presence of lymphedema, and histopathological analyses were conducted to evaluate the M1/M2 macrophage ratio, fibrosis accumulation, and lymph angiogenesis. Results: The micro-computed tomography evaluation revealed that 75% of the rats of group A exhibited long-lasting lymphedema. In group B, the initial lymphedema ratio was the lowest, affecting only 25% of the rats. After ligating the main vessels, a linear lymphatic microvascular structure was observed in groups B and C. Group B had a significant increase in M2 macrophages and newly formed lymphatic vessels (p < 0.05). However, group A showed a significant elevation of M1 macrophages and collagen accumulation (p < 0.05) in the surgically treated hind limb. Conclusions: Both histological analyses and clinical results reported a relevant influence of calcitriol administration. Among all groups, the most favorable outcomes were seen in group B (prophylaxis group). Hence, calcitriol administration could play a crucial role in enhancing the migration of M2 macrophages to the damaged tissue. Such migration may contribute to lymphedema resolution either by enhancing the organization of superficial lymphatic vessels or resolving fibrosis, or with a combination of both these mechanisms.

A Core-Brush Nanoplatform with Enhanced Lubrication and Anti-Inflammatory Properties for Osteoarthritis Treatment.

Osteoarthritis (OA) is recognized as a highly friction-related joint disease primarily associated with increased joint friction and inflammation due to pro-inflammatory M1-type macrophage infiltration in the articular cavity. Therefore, strategies to simultaneously increase lubrication and relieve inflammation to remodel the damaged articular microenvironment are of great significance for enhancing its treatment. Herein, a multifunctional core-brush nanoplatform composed of a ROS-scavenging polydopamine-coated SiO2 core and lubrication-enhancing zwitterionic poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) brush and loaded with the anti-inflammatory drug curcumin by a reactive oxygen species (ROS)-liable conjugation (named as SiO2@PP-Cur) is rationally designed. Benefiting from the grafted zwitterionic PMPC brush, a tenacious hydration layer with enhanced lubricity for reducing joint abrasions is developed. More importantly, based on the mono-iodoacetic acid-induced arthritis (MIA) rat model, intra-articular injection of SiO2@PP-Cur nanoplatform can effectively alleviate articular inflammation via promoting macrophage polarization from the pro-inflammatory M1 to anti-inflammatory M2 state by activating the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway and attenuating the degradation of cartilage matrix, resulting in the remodeling of the damaged microenvironment into a pro-regenerative microenvironment. As a result, SiO2@PP-Cur can considerably inhibit OA progression. Therefore, the work may provide a novel strategy for the development of an advanced core-brush nanoplatform for enhanced OA therapy.

Supplementation of Miso to a Western-Type Diet Stimulates ILC3s and Decreases Inflammation in the Small Intestine.

Western-type diets (WDs) damage the intestinal barrier by disrupting the gut microbiota composition and causing inflammation, leading to the development of obesity, type 2 diabetes, and non-alcoholic fatty liver disease. Short-chain fatty acids (SCFAs) are produced by the gut microbiota and found in fermented foods and can stimulate the anti-inflammatory action of type 3 innate lymphoid cells (ILCS3s) in the intestine. This study hypothesised that supplementing miso, a Japanese fermented food, to a WD could increase the levels of SCFAs and thus stimulate ILC3s, decreasing inflammation in the intestine and protecting intestinal barrier integrity. Mice with RORγt total (KI/KI) or partial (KI/w) knockout were fed a high-fat high-sugar diet (HFHSD) for eight weeks as a model of WD. Half of the mice received miso supplementation in addition to the HFHSD. Weight gain, glucose tolerance and insulin resistance, intestinal barrier integrity, intestinal immunity, and liver condition were assessed. Miso supplementation increased SCFA levels in the small intestine, which stimulated ILC3 function in KI/w mice. Glucose tolerance was improved, intestinal barrier integrity was ameliorated, and mucus production was increased. The level of IL-22 was increased, while pro-inflammatory ILC1s, M1 macrophages, TNF-α, and IL-1β were decreased. Liver condition was not affected. This study demonstrated that miso supplementation influenced several factors involved in inflammation and intestinal barrier integrity by stimulating ILC3s in RORγt heterozygous mice. Moreover, it showed that the number of ILC3s is not the key factor in immune regulation, but rather the ability of ILC3 to produce IL-22 and employ it to control the immune response in the small intestine.

Analysis of tumor infiltrating immune cells in Kaposi sarcoma lesions discovers shifts in macrophage populations.

Limited information exists about the types of immune cells present in Kaposi sarcoma (KS) lesions, especially in KS in the gastrointestinal tract. Using previously reported RNA-sequencing results from Kaposi sarcoma lesions in skin and gastrointestinal tract with normal matched tissues from the same patients at the same time, we investigated changes in lymphocytes in these tissues. We employed a computational method that determines changes in cell type distributions using KS lesion transcriptome data compared to a reference set of RNA expression patterns of purified immune cells. Since secreted cytokines and chemokines from KSHV-infected cells may influence the microenvironment of Kaposi sarcoma lesions, we performed cytokine profiling of conditioned media from KSHV-infected primary human dermal lymphatic endothelial cells. We also measured how this conditioned media altered the differentiation of macrophages in cell culture assays. These results suggested that factors in conditioned media from KSHV-infected endothelial cells promoted differentiation of a promonocytic cell line to proinflammatory macrophages.

Alternations in inflammatory macrophage niche drive phenotypic and functional plasticity of Kupffer cells

Inflammatory signals lead to recruitment of circulating monocytes and induce their differentiation into pro-inflammatory macrophages. Therefore, whether blocking inflammatory monocytes can mitigate disease progression is being actively evaluated. Here, we employ multiple lineage-tracing models and show that monocyte-derived macrophages (mo-mac) are the major population of immunosuppressive, liver metastasis-associated macrophages (LMAM), while the proportion of Kupffer cells (KC) as liver-resident macrophages is diminished in metastatic nodules. Paradoxically, genetic ablation of mo-macs results in only a marginal decrease in LMAMs. Using a proliferation-recording system and a KC-tracing model in a monocyte-deficient background, we find that LMAMs can be replenished either via increased local macrophage proliferation or by promoting KC infiltration. In the latter regard, KCs undergo transient proliferation and exhibit substantial phenotypic and functional alterations through epigenetic reprogramming following the vacating of macrophage niches by monocyte depletion. Our data thus suggest that a simultaneous blockade of monocyte recruitment and macrophage proliferation may effectively target immunosuppressive myelopoiesis and reprogram the microenvironment towards an immunostimulatory state.

Application of an in vitro neuroinflammation model to evaluate the efficacy of magnesium-lithium alloys.

Mg-Li alloys can be promising candidates as bioresorbable Li-releasing implants for bipolar disorder and other neurodegenerative disorders. In order to compare the therapeutic efficacy of conventional Li salts and Li delivered through Mg-Li alloy extracts, we tested an in vitro model based on the neuroinflammation hypothesis of mood disorders (peripheral inflammation inducing neuroinflammation) wherein, a coculture of microglia and astrocytes was treated with conditioned medium from pro-inflammatory macrophages. Two alloys, Mg-1.6Li and Mg-9.5Li, were tested in the form of material extracts and well-known outcomes of Li treatment such as GSK3β phosphorylation (indirect flow cytometry) and influence on inflammation-related gene expression (qPCR) were compared against Li salts. This is the first study demonstrating that Li can increase the phosphorylation of GSK3β in glial cells in the presence of excess Mg. Furthermore, Mg-Li alloys were more effective than Li salts in downregulating IL6 and upregulating the neurotrophin GDNF. Mg had no antagonistic effects toward Li-driven downregulation of astrogliosis markers. Overall, the results provide evidence to support further studies employing Mg-Li alloys for neurological applications.