Adherent Macrophages Research Articles

Myeloid-specific deficiency of pregnane X receptor decreases atherosclerosis in LDL receptor-deficient mice

The pregnane X receptor (PXR) is a nuclear receptor that can be activated by numerous drugs and xenobiotic chemicals. PXR thereby functions as a xenobiotic sensor to coordinately regulate host responses to xenobiotics by transcriptionally regulating many genes involved in xenobiotic metabolism. We have previously reported that PXR has pro-atherogenic effects in animal models, but how PXR contributes to atherosclerosis development in different tissues or cell types remains elusive. In this study, we generated an LDL receptor-deficient mouse model with myeloid-specific PXR deficiency (PXRΔMyeLDLR-/-) to elucidate the role of macrophage PXR signaling in atherogenesis. The myeloid PXR deficiency did not affect metabolic phenotypes and plasma lipid profiles, but PXRΔMyeLDLR-/- mice had significantly decreased atherosclerosis at both aortic root and brachiocephalic arteries compared with control littermates. Interestingly, the PXR deletion did not affect macrophage adhesion and migration properties, but reduced lipid accumulation and foam cell formation in the macrophages. PXR deficiency also led to decreased expression of the scavenger receptor CD36 and impaired lipid uptake in macrophages of the PXRΔMyeLDLR-/- mice. Further, RNA-Seq analysis indicated that treatment with a prototypical PXR ligand affects the expression of many atherosclerosis-related genes in macrophages in vitro. These findings reveal a pivotal role of myeloid PXR signaling in atherosclerosis development and suggest that PXR may be a potential therapeutic target in atherosclerosis management.

Effects of Compressive and Tensile Strain on Macrophages during Simulated Orthodontic Tooth Movement.

During orthodontic tooth movement (OTM) to therapeutically correct the position of misaligned teeth, thus improving oral health and quality of life, fibroblasts, macrophages, and other immune cells within the periodontal ligament (PDL), which connects a tooth to its surrounding bone, are exposed to compressive and tensile strain. While it is known that PDL fibroblasts are critically involved in the biological regulation of OTM by a mechanotransductively triggered release of cytokines, it is unclear whether macrophages also react to pressure and tension in a similar manner thus impacting on or mediating OTM. RAW264.7 macrophages were seeded onto conventional 6-well cell culture plates for pressure or on Bioflex plates for tension assays and preincubated for 24 h. For in vitro simulation of physiological orthodontic compressive or tensile strain for 2 h, 4 h, 24 h, and 48 h, glass discs (2 g/cm2) were placed or adherent macrophages isotropically stretched for 16%, respectively. We determined cell number, cytotoxicity, and gene/protein expression of Vegf-a/VEGF-A (macrophage-mediated angiogenesis), Mmp-8/9 (extracellular matrix reorganization), and Cox-2/PG-E2, Il-6/IL-6, and Tnf-α/TNF-α (proinflammatory mediators) by RT-qPCR and ELISA. Compressive but not tensile strain resulted in a significant reduction in cell number after only 2 h. Mmp-8 and Mmp-9 expression was significantly enhanced within 24 h of compressive and in part tensile strain. Significantly increased Vegf-a/VEGF-A expression was detected within 4 h of pressure, but not during application of tensile strain. Expression of proinflammatory mediators Cox-2/PG-E2, Il-6/IL-6, and Tnf-α/TNF-α was significantly increased as early as 2-4 h after application of compressive or tensile strain. Our results indicate that macrophages respond early on to compressive and tensile strain occurring during OTM with an enhanced gene expression of proinflammatory cytokines, which could affect PDL fibroblasts, osteoblasts, and immune cells triggering or enhancing the biological mechanisms and osteoclastogenesis underlying OTM.

Dopamine-Mediated Zwitterionic Polyelectrolyte-Coated Polypropylene Hernia Mesh with Synergistic Anti-inflammation Effects

Over 20 million ventral hernia repairs are performed worldwide annually and only a minority (<10%) of cases are not mesh-based. However, even polypropylene (PP), endorsed as the "gold standard" of all prosthetic materials used in this field, is still subject to many complications caused by the foreign body reaction (FBR). Here, we describe the buildup of dopamine-mediated zwitterionic poly(sulfobetaine methacrylate) (PSBMA) coatings to inhibit nonspecific protein adsorption. Based on the universal adhesive ability of polydopamine (PDA), PSBMA has been coated on the PP mesh surface via two strategies: sequential deposition (PSBMA-PDA-PP) and co-deposition (PSBMA@PDA-PP). The presence of PSBMA shows great contribution to obviously decreased hydrophobicity of the PP surface (WCAco = 36.3° and WCAseq = 30.7°) as well as improved protein resistance (Reductionco = 74% and Reductionseq = 82%). Notably, as the intermedia between PP and PSBMA, PDA can endow the PP mesh with antioxidant activity, further featuring synergistic anti-inflammation therapeutic effect when coupled with PSBMA. With almost equal surface content of PSBMA, PSBMA-PDA-PP exhibited a more superior ability against macrophage adhesion and proliferation and showed more significantly decreased releases of TNF-α and IL-6 (p < 0.05) than those of PSBMA@PDA-PP, fundamentally attributed to its more neutral surface potential and the protection for polyphenols of PDA from oxidation with PSBMA as the outer layer. Furthermore, the coating layers demonstrated good stability and no sacrifice of the pristine mechanical property. The proposed dopamine-mediated PSBMA coatings possess high potential in biomedical implant areas for attenuating the FBR.

Pharmacological targeting of neurotensin response by diet-derived EGCG in macrophage-differentiated HL-60 promyelocytic leukemia cells

The neurotensin (NTS)/neurotensin receptor (NTSR) axis in chronic B cell leukemia regulates B cell proliferation. We questioned whether a similar NTS/NTSR axis was functional in acute myeloid leukemia (AML), and to what extent it could become a pharmacological target for epigallocatechin-3-gallate (EGCG), a diet-derived polyphenol with chemopreventive properties. Analysis of NTS, NTSR1, NTSR2, and NTSR3 gene expression in AML patients using Kaplan-Meier plots highlighted NTSR3 as a poor clinical prognosis biomarker. EGCG was tested on NTSR3 function and gene/protein expression in undifferentiated and phorbol 12-myristate 13-acetate (PMA)-differentiated HL-60 cells, an acute promyelocytic leukemia subset cell line model from AML, which can differentiate into CD11bHigh/CD14Low adherent macrophages. We found that high level of gene, total protein, and cell surface expression of NTSR3 correlated with clinical samples of highly differentiated CD11b hematopoietic cells. Increased NTSR3 expression, NTS internalization, and matrix metalloproteinase-9 expression, was recapitulated in HL60-differentiated CD11bHigh macrophages, where chemotaxis in response to NTS was reduced through decreased Erk, MEK and Src signaling. EGCG prevented PMA-induced CD11b expression, NTS internalization and NTSR3-induced expression. Targeting of hematopoietic cell differentiation by EGCG could alter the NTS/NTSR3 signaling axis and possibly prevent the acquisition of an invasive phenotype.

Glycocalyx‐Like Hydrogel Coatings for Small Diameter Vascular Grafts

AbstractNovel biological vascular conduits, such as decellularized tissue engineered vascular grafts (TEVGs) are hindered by high thrombogenicity. To mimic the antithrombogenic surface of native vessels with a continuous glycosaminoglycan layer that is present on endothelial cells (ECs), a hyaluronic acid (HA) modified surface is established, to effectively shield blood platelets from collagen‐triggered activation. Using the amine groups present on 4 mm diameter decellularized TEVGs, a continuous HA hydrogel coating is built via a bifunctional thiol‐reactive cross‐linker, thereby avoiding nonspecific collagen matrix cross‐linking. The HA hydrogel layer recreates a luminal wall, “hiding” exposed collagen from the bloodstream. In vitro blood tests show that adhered platelets, fibrinogen absorption, and fibrin formation on HA‐coated decellularized TEVGs are significantly lower than on uncoated decellularized TEVGs. The HA surface also inhibits macrophage adhesion in vitro. HA‐coated decellularized syngeneic rat aortae (≈1.5 mm diameter), and TEVGs in rat and canine models, respectively, are protected from aggressive thrombus formation, and preserve normal blood flow. Re‐endothelialization is also observed. HA‐coated TEVGs may be an off‐the‐shelf small‐diameter vascular graft with dual benefits: antithrombogenic protection and promotion of endothelium.

Galectin-3 Identifies a Subset of Macrophages With a Potential Beneficial Role in Atherosclerosis.

Galectin-3 (formerly known as Mac-2), encoded by the LGALS3 gene, is proposed to regulate macrophage adhesion, chemotaxis, and apoptosis. We investigated the role of galectin-3 in determining the inflammatory profile of macrophages and composition of atherosclerotic plaques. Approach and Results: We observed increased accumulation of galectin-3-negative macrophages within advanced human, rabbit, and mouse plaques compared with early lesions. Interestingly, statin treatment reduced galectin-3-negative macrophage accrual in advanced plaques within hypercholesterolemic (apolipoprotein E deficient) Apoe-/- mice. Accordingly, compared with Lgals3+/+:Apoe-/- mice, Lgals3-/-:Apoe-/- mice displayed altered plaque composition through increased macrophage:smooth muscle cell ratio, reduced collagen content, and increased necrotic core area, characteristics of advanced plaques in humans. Additionally, macrophages from Lgals3-/- mice exhibited increased invasive capacity in vitro and in vivo. Furthermore, loss of galectin-3 in vitro and in vivo was associated with increased expression of proinflammatory genes including MMP (matrix metalloproteinase)-12, CCL2 (chemokine [C-C motif] ligand 2), PTGS2 (prostaglandin-endoperoxide synthase 2), and IL (interleukin)-6, alongside reduced TGF (transforming growth factor)-β1 expression and consequent SMAD signaling. Moreover, we found that MMP12 cleaves macrophage cell-surface galectin-3 resulting in the appearance of a 22-kDa fragment, whereas plasma levels of galectin-3 were reduced in Mmp12-/-:Apoe-/- mice, highlighting a novel mechanism where MMP12-dependent cleavage of galectin-3 promotes proinflammatory macrophage polarization. Moreover, galectin-3-positive macrophages were more abundant within plaques of Mmp12-/-:Apoe-/- mice compared with Mmp12+/+:Apoe-/- animals. This study reveals a prominent protective role for galectin-3 in regulating macrophage polarization and invasive capacity and, therefore, delaying plaque progression.

Role of TRPV4 mechanosensing in foreign body response and giant cell formation

Implantable biomaterials and medical devices are used in millions of procedures each year worldwide. However, the implantation of these devices leads to the development of a foreign body response (FBR), a chronic inflammatory condition that can ultimately lead to implant failure, which may cause harm to or death of the patient. Despite decades of research, the mechanisms underlying the FBR remain poorly understood, as neither the materials from which these implants are made nor their chemical properties can explain triggering of the FBR. Hallmarks of the FBR include activation of macrophages at the tissue‐implant interface, formation of destructive foreign body giant cells (FBGCs), and development of fibrous tissue that encapsulates the implant. Here, we report that genetic ablation of TRPV4, an ion channel in the transient receptor potential vanilloid family, and which is a mechanosensor, is possibly the mediator of FBR. Specifically, we found that: 1) Trpv4 deletion in mice prevented macrophage accumulation, FBGC formation, and collagen accumulation in a subcutaneous implantation model; 2) the severity of the in vivo macrophage accumulation at the tissue‐implant interface was dependent on the stiffness of the implant; 3) genetic ablation of TRPV4 blocked macrophage adhesion and spreading on stiff matrix in bone marrow derived macrophages; and 4) genetic deficiency of TRPV4 blocked cytokine‐induced FBGC formation, which was restored by lentivirus‐mediated TRPV4 reintroduction. Furthermore, we found that: 5) TRPV4 activity (calcium influx) was augmented in response to a biomechanical stimulus; and 6) loss of TRPV4 activity reduced internal stiffness in macrophages as determined by Atomic Force Microscopy analysis. Taken together, these results suggest an important, previously unknown role for TRPV4 in FBR and giant cell formation.Support or Funding InformationFunding: This work was supported by NIH (1R01EB024556‐01) and NSF (CMMI‐1662776) grants to Shaik O. Rahaman.

CTRP3 Prevents Macrophage Activation

Sepsis is a life‐threatening medical emergency that is caused by the body’s extreme response to an infection. The initial infection results in an overproduction of cytokines which recruits additional immune cells. Adipose tissue is an active endocrine organ which secrets several anti‐inflammatory mediators, collectively called adipokines which could contribute to the control of the body’s response to a septic event. Our previous work has identified that the circulating levels of the anti‐inflammatory adipokine called C1q TNF Related Protein 3 (CTRP3) is significantly reduced in response to sepsis. We have also demonstrated that CTRP3 binds directly to circulating macrophages. Therefore, the purpose of this project was to examine the potential anti‐inflammatory effects of CTRP3 on macrophages.METHODSThioglycolate‐induced peritoneal macrophages were isolated from CTRP3 overexpressing transgenic (Tg) and wild‐type (WT) mice. The isolated macrophages were then treated with lipopolysaccharides (LPS). Morphological changes were analyzed via bright‐field microscopy and the transcription levels of the inflammatory cytokines tumor necrosis factor alpha (TNF) and interleukin‐6 (IL6) were measured by Real‐Time PCR.RESULTSMorphological qualitative analysis indicated that LPS reduced macrophage adhesion and the effect was more pronounced in the Tg macrophages. Gene expression analysis demonstrated that LPS stimulation significantly increased IL6 and TNF levels in all samples (~4000‐fold and 300‐fold respectively). However, LPS‐induced increase in IL6 expression was significantly attenuated in Tg macrophages (fold elevation compared to vehicle treated: WT 273±92; Tg 78±68). There was no difference in LPS‐induced TNF expression in Tg compared to the WT macrophages.CONCLUSIONCombined these data indicated that CTRP3 attenuates the ability of LPS to activate the pro‐inflammatory functions of the macrophages. Future studies are needed to confirm these findings and to determine the unique mechanism for the CTRP3‐induced alterations to macrophages. Regardless, CTRP3 is a unique contributor to macrophage’s response to inflammatory signals.Support or Funding Information1R15DK114740

Photofunctionalized and Drug-Loaded TiO2 Nanotubes with Improved Vascular Biocompatibility as a Potential Material for Polymer-Free Drug-Eluting Stents.

Implantation of a drug-eluting stent is the most common treatment method for patients with cardiovascular atherosclerosis. However, this treatment may delay re-endothelialization, and the drug polymer-coated stent may induce thrombosis months after a stent implantation. The development of polymer-free drug-eluting stents is a promising approach to overcome these shortcomings. Titanium dioxide nanotubes (TiO2-NTs) are excellent drug carriers and have been considered as a potential material for polymer-free drug-eluting stents. However, TiO2-NTs reportedly induce severe blood clotting, which is a significant shortcoming for use as a stent. Vascular stents must be compatible with blood and must have antibacterial, anti-inflammatory, and selective inhibitory activities in the abnormal hyperplasia of smooth muscle cells, instead of delaying the re-endothelialization of endothelial cells. To meet these requirements, we presented a composite material that featured ultraviolet (UV) irradiation of TiO2-NTs-containing silver nanoparticles (AgNPs). The AgNPs were loaded in the lumen of TiO2-NTs as a representative compound to suppress the inflammatory response and hyperplasia. UV irradiation was performed as a novel method to improve the anticoagulant ability of the AgNP-loaded TiO2-NTs. The chemical state and biocompatibility of the UV-TiO2-NTs@AgNPs were evaluated. UV irradiation strongly improved the anticoagulant ability of the TiO2-NTs and moderated the release of Ag+ from AgNPs, which selectively suppressed the inflammatory response and hyperplasia. Furthermore, the UV-TiO2-NTs@AgNPs-2 displayed enhanced biocompatibility evidenced by the inhibition of platelet adhesion, bactericidal activity, selective suppression of the smooth muscle cell proliferation, and inhibition of the adhesion of macrophages. The collective findings indicate the potential of the photofunctionalized TiO2-NTs loaded with AgNPs as a material for polymer-free drug-eluting stents.

Coating Polyurethane with Palmitoleic Acid and Bovine Serum Albumin to Prevent the Host Response to Foreign Materials

Macrophages are cells of the immune system that play a pivotal role in the host inflammatory response by attacking and engulfing any foreign molecule not seen as ‘self.’ They also help regulate the host response by releasing a variety of cytokines and growth factors that act as signals to other cells to amplify the host response. However, the host response causes degradation of implanted medical devices composed of polyurethane as well as other synthetic materials which it does not identify as self. Research was undertaken to investigate the potential of coating polyurethane with the self-like molecules palmitoleic acid and albumin to reduce or prevent the body’s host response from damaging implanted medical devices. Using an in vitro THP-1 bioassay, polyurethane films coated with palmitoleic acid and bovine serum albumin showed a reduction in macrophage adherence. The individually coated palmitoleic acid and bovine serum albumin films significantly reduced the number of cells attached to the films with increasing concentration while the films coated with the conjugate of both showed no statistical difference. This suggests the potential role of self-like molecules in reducing the inflammatory response to foreign materials. KEYWORDS: Macrophages; host inflammatory response; THP-1; prosthetics; palmitoleic acid; bovine serum albumin; cytokines; immune system

Adhesion, motility and matrix-degrading gene expression changes in CSF-1-induced mouse macrophage differentiation.

Migratory macrophages play critical roles in tissue development, homeostasis and disease, so it is important to understand how their migration machinery is regulated. Whole-transcriptome sequencing revealed that CSF-1-stimulated differentiation of bone marrow-derived precursors into mature macrophages is accompanied by widespread, profound changes in the expression of genes regulating adhesion, actin cytoskeletal remodeling and extracellular matrix degradation. Significantly altered expression of almost 40% of adhesion genes, 60-86% of Rho family GTPases, their regulators and effectors and over 70% of extracellular proteases occurred. The gene expression changes were mirrored by changes in macrophage adhesion associated with increases in motility and matrix-degrading capacity. IL-4 further increased motility and matrix-degrading capacity in mature macrophages, with additional changes in migration machinery gene expression. Finally, siRNA-induced reductions in the expression of the core adhesion proteins paxillin and leupaxin decreased macrophage spreading and the number of adhesions, with distinct effects on adhesion and their distribution, and on matrix degradation. Together, the datasets provide an important resource to increase our understanding of the regulation of migration in macrophages and to develop therapies targeting disease-enhancing macrophages.

Alantolactone mitigates renal injury induced by diabetes via inhibition of high glucose-mediated inflammatory response and macrophage infiltration

Background: Inflammatory response plays a crucial role in the occurrence and development of diabetic nephropathy (DN). Drugs that carry anti-inflammatory effects have the potential to treat diabetic nephropathy. It’s reported that alantolactone (ALA), a natural product, has a variety of pharmacological effects against inflammation and oxidation. However, the specific effects of alantolactone on DN and the mechanisms underlying alantolactone remain elusive. Therefore, the present study aimed to probe whether ALA could mitigate inflammation as mediated by high glucose (HG) in NRK-52E cells and reduce renal injury caused by diabetic nephropathy.Materials and methods: The anti-inflammatory effect of ALA was evaluated in the present study using ELISA and RT-qPCR. Western blot and macrophage adhesion assay were then performed to confirm anti-macrophage adhesion and the protein expression of cell adhesion molecules. Finally, the effect of ALA and its underlying mechanism was evaluated in vivo.Results: Results showed that ALA curbed HG-stimulated expression of macrophage adhesion and pro-inflammatory cytokines in renal NRK-52E cells. In addition, both pro-inflammatory cytokines and NF-kappa B witnessed reduced expression or activity in oral administration with ALA in vivo, thus inhibiting the increase of serum creatinine and urea nitrogen (BUN) levels. This in consequence ameliorated fibrosis and stemmed pathological worsening of diabetic renal tissues.Conclusions: These findings suggest that ALA may hold promise in the treatment of DN, and importantly, the anti-inflammatory system may prove to be a new strategy to treat human DN.

Epithelial and Endothelial Adhesion of Immune Cells Is Enhanced by Cardiotonic Steroid Signaling Through Na+/K+-ATPase-α-1.

BackgroundRecent studies have highlighted a critical role for a group of natriuretic hormones, cardiotonic steroid (CTS), in mediating renal inflammation and fibrosis associated with volume expanded settings, such as chronic kidney disease. Immune cell adhesion is a critical step in the inflammatory response; however, little is currently understood about the potential regulatory role of CTS signaling in this setting. Herein, we tested the hypothesis that CTS signaling through Na+/K+‐ATPase α‐1 (NKA α‐1) enhances immune cell recruitment and adhesion to renal epithelium that ultimately advance renal inflammation.Methods and ResultsWe demonstrate that knockdown of the α‐1 isoform of Na/K‐ATPase causes a reduction in CTS‐induced macrophage infiltration in renal tissue as well reduces the accumulation of immune cells in the peritoneal cavity in vivo. Next, using functional adhesion assay, we demonstrate that CTS‐induced increases in the adhesion of macrophages to renal epithelial cells were significantly diminished after reduction of NKA α‐1 in either macrophages or renal epithelial cells as well after inhibition of NKA α‐1‐Src signaling cascade with a specific peptide inhibitor, pNaKtide in vitro. Finally, CTS‐induced expression of adhesion markers in both endothelial and immune cells was significantly inhibited in an NKA α‐1‐Src signaling dependent manner in vitro.ConclusionsThese findings suggest that CTS potentiates immune cell migration and adhesion to renal epithelium through an NKA α‐1–dependent mechanism; our new findings suggest that pharmacological inhibition of this feed‐forward loop may be useful in the treatment of renal inflammation associated with renal disease.

Study on the potential mechanism of anti-inflammatory activity of covalently immobilized hyaluronan and heparin.

Inflammation and subsequent fibrotic encapsulation that occur after implantation of biomaterials are issues that fostered efforts in designing novel biocompatible materials to modulate the immune response. In this study, glycosaminoglycans (GAG) like hyaluronic acid (HA) and heparin (Hep) that possess anti-inflammatory activity were covalently bound to NH2 -modified surfaces using EDC/NHS cross-linking chemistry. Immobilization and physical surface properties were characterized by atomic forces microscopy, water contact angle studies and streaming potential measurements demonstrating the presence of GAG on the surfaces that became more hydrophilic and negatively charged compared to NH2 -modified. THP-1 derived macrophages were used here to study the mechanism of action of GAG to affect the inflammatory responses illuminated by studying macrophage adhesion, the formation of multinucleated giant cells (MNGCs) and IL-1β release that were reduced on GAG-modified surfaces. Detailed investigation of the signal transduction processes related to macrophage activation was performed by immunofluorescence staining of NF-κB (p65 subunit) together with immunoblotting. We studied also association and translocation of FITC-labeled GAG. The results show a significant decrease in NF-κB level as well as the ability of macrophages to associate with and take up HA and Hep. These results illustrate that the anti-inflammatory activity of GAG is not only related to making surfaces more hydrophilic, but also their active involvement in signal transduction processes related to inflammatory reactions, which may pave the way to design new anti-inflammatory surface coatings for implantable biomedical devices.

Protective effects of beet (Beta vulgaris) leaves extract against oxidative stress in endothelial cells in vitro.

Beetroot is an herb used worldwide as a food product, raw material for food industry, ethanol production and source of food coloring. Beet leaves are an unconventional food with antioxidant properties, which might neutralize reactive oxygen species (ROS) induced by oxidized Low-Density Lipoprotein (LDL) present in dyslipidemias. This study aimed to elucidate the effects of beet leaves on the suppression of LDL oxidative processes. Beet leaves extract was produced, characterized, and tested for its antioxidant capacity using endothelial cells in vitro. A model of human umbilical vein endothelial cells was used in various tests, including viability assay, molecular analysis of antioxidant genes, ROS labeling, and macrophage adhesion assay. The extract improved the antioxidative protection of endothelial cells against different agents including oxidized LDL-cholesterol and H2 O2 . It acted on ROS directly due to its high content of natural antioxidants, but also due to the activation and improvement of cellular defenses such as Superoxide dismutase 1, Superoxide dismutase 2, and catalase. The inhibition of LDL-mediated oxidative effects on endothelial cells may turn this unconventional food a functional food with great potential for phytotherapy of atherosclerosis as an adjuvant for medicinal treatments.

Novel 3D Printed Biodegradable Polyurethane-Urea Elastomer Recapitulate Skeletal Muscle Structure and Function

Effective skeletal muscle tissue engineering relies on the control over the scaffold architecture for providing the muscle cells with required directionality, together with mechanical property match with the surrounding tissue. Although recent advances in 3D printing fulfills the first requirement, the available synthetic polymers are either too rigid or show unfavorable surface and degradation profiles for the latter. In addition, natural polymers that are generally used as hydrogels, lack the required mechanical stability to withstand the forces exerted during muscle contraction. Therefore, one of the most important challenges in the 3D printing of soft and elastic tissues such as skeletal muscle is the limitation of the availability of elastic, durable and biodegradable biomaterials. Herein, we have synthesized novel, biocompatible and biodegradable, elastomeric, segmented polyurethane and polyurethane-urea (TPU) copolymers which are amenable for extrusion 3D printing and show high elasticity, low rigidity, controlled biodegradability and improved wettability, compared to conventional polycaprolactone (PCL) and PCL based TPUs. The degradation profile of the 3D printed TPU scaffold was in line with the potential tissue integration and scaffold replacement process. Even though TPU attracts macrophages in 2D configuration, its 3D printed form showed limited activated macrophage adhesion and induced muscle-like structure formation by C2C12 mouse myoblasts in vitro, while resulting in a significant increase in muscle regeneration in vivo in a tibialis anterior defect in a rat model. Effective muscle regeneration was confirmed with histopathological assessment as well as gait analysis and micro-CT evaluation. These results demonstrate that matching the tissue properties for a given application via use of tailor-made polymers can substantially contribute to the regenerative outcomes of 3D printed tissue engineering scaffolds.

Влияние аналогов индолицидина на функциональную активность макрофагов и нейтрофилов при экспериментальном пародонтите у крыс

На 7 сут после моделирования экспериментального пародонтита отмечено уменьшение относительного числа макрофагов в перитонеальном смыве у крыс с пародонтитом, но увеличение количества адгезированных клеток. Снижение адгезивной способности макрофагов установлено только на 14 сут эксперимента. Фагоцитарная активность нейтрофилов уменьшалась у животных с пародонтитом, что проявлялось снижением фагоцитарного и опсоно-фагоцитарного индексов на 40 и 43 %, соответственно, на 7 сут эксперимента (p &lt; 0,0) и фагоцитарного индекса на 31 % на 14 сут (p &lt; 0,01). Через 21 сут количество фагоцитирующих нейтрофилов не отличалось достоверно от аналогичного показателя у интактных крыс. При этом не установлено угнетения поглотительной способности фагоцитов у животных с пародонтитом. Аналоги индолицидина в дозе 500 мкг/кг внутрибрюшинно однократно в течение 7 дней оказывали стимулирующее влияние как на относительное количество макрофагов в перитонеальном смыве (индолицидин № 7 — на 24 % и индолицидин № 8 — на 20 %, p &lt; 0,001), так и на процентное содержание адгезированных макрофагов: начиная с 14 сут эксперимента их увеличение составило 22 и 17 % при применении индолицидина № 7 и индолицидина № 8, соответственно, у крыс с пародонтитом по сравнению с животными контрольной группы (p &lt; 0,05). Изучаемые аналоги индолицидина оказывали стимулирующее влияние на фагоцитарную активность нейтрофилов на всех сроках наблюдения, что проявлялось увеличением всех исследуемых показателей: фагоцитарного индекса на 43 – 50 % (p &lt; 0,001), фагоцитарного числа на 12 – 50 % (p &lt; 0,05) и опсоно-фагоцитарного индекса на 77 – 173 % (p &lt; 0,05). Стимулирующее действие индолицидина № 7 на фагоцитарную активность нейтрофилов периферической крови и адгезивную активность перитонеальных макрофагов было выше по сравнению с действием индолицидина № 8. В частности, на 21 сут только индолицидин № 7 вызывал увеличение фагоцитарного числа и относительного количества адгезированных перитонеальных макрофагов.

ECM-mimicking nanofibrous matrix coaxes macrophages toward an anti-inflammatory phenotype: Cellular behaviors and transcriptome analysis

An in-depth understanding of biomaterial cues to selectively polarize macrophages is beneficial in the design of “immuno-informed” biomaterials that positively interact with the immune system to dictate a favorable macrophage response following implantation. Given the promising future of ECM-mimicking nanofibrous biomaterials in biomedical application, it is essential to elucidate how their intrinsic cues, especially the nanofibrous architecture, affect macrophages. In the present study, we evaluated how the nanofibrous architecture of a gelatin matrix modulated macrophage responses from the perspectives of cellular behaviors and a transcriptome analysis. In our results, the nanofibrous surface attenuated M1 polarization and down-regulated the inflammatory responses of macrophages compared with a smooth surface. Besides, the cell-material interaction was up-regulated and the adhered macrophages tended to maintain an original, non-polarized state on the nanofibrous matrix. Accordingly, whole transcriptome analysis revealed that nanofibrous architecture up-regulated the pathways related to ECM-receptor interaction and down-regulated pathways related to pro-inflammation. This study provides a panoramic view of the interaction between macrophages and nanofibers, and offers valuable information for the design of immunomodulatory ECM-mimicking biomaterials for tissue regeneration.

Effects of argon plasma treatment on the osteoconductivity of bone grafting materials.

The osteoconductive properties of bone grafting materials represent one area of research for the management of bony defects found in the fields of periodontology and oral surgery. From a physico-chemical aspect, the wettability of the graft has been demonstrated to be one of the most important factors for new bone formation. It is also well-known that argon plasma treatment (PAT) and ultraviolet irradiation (UV) may increase the surface wettability and, consequently, improve the regenerative potential of the bone grafts. Therefore, the aim of the present in vitro study was to evaluate the effect of PAT and UV treatment on the osteoconductive potential of various bone grafts. The following four frequently used bone grafts were selected for this study: synthetic hydroxyapatite (Mg-HA), biphasic calcium phosphate (BCP), cancellous and cortical xenogenic bone matrices (CaBM, CoBM). Sixty-six serially numbered disks 10 mm in diameter were used for each graft material and randomly assigned to the following three groups: test 1 (PAT), test 2 (UV), and control (no treatment). Six samples underwent topographic analysis using SEM pre- and post-treatments to evaluate changes in surface topography/characteristics. Additionally, cell adhesion and cell proliferation were evaluated at 2 and 72 h respectively following incubation in a three-dimensional culture system utilizing a bioreactor. Furthermore, the effects of PAT and UV on immune cells were assessed by measuring the viability of human macrophages at 24 h. The topographic analysis showed different initial morphologies of the commercial biomaterials (e.g., Mg-HA and BCP showed flat morphology; BM samples were extremely porous with high roughness). The surface analysis following experimental treatments did not demonstrate topographical difference when compared with controls. Investigation of cells demonstrated that PAT treatment significantly increased cell adhesion of all 4 evaluated bone substitutes, whereas UV failed to show any statistically significant differences. The viability test revealed no differences in terms of macrophage adhesion on any of the tested surfaces. Within their limitations, the present results suggest that treatment of various bone grafting materials with PAT appears to enhance the osteoconductivity of bone substitutes in the early stage by improving osteoblast adhesion without concomitantly affecting macrophage viability. Treatment of bone grafts with PAT appears to result in faster osseointegration of the bone grafting materials and may thus favorably influence bone regeneration.

Pharmacological blockage of ICAM-1 improves angiotensin II-induced cardiac remodeling by inhibiting adhesion of LFA-1+ monocytes.

Intercellular adhesion molecule-1 (ICAM-1) is a member of an immunoglobulin-like superfamily of adhesion molecules that mediate leukocyte adhesion to vascular endothelium and are involved in several cardiovascular diseases, including ischemia-reperfusion injury, myocardial infarction, and atherosclerosis. However, the role of ICAM-1 in angiotensin II (ANG II)-induced cardiac remodeling in mice remains unclear. Wild-type mice were administered an IgG control or ICAM-1 neutralizing antibody (1 and 2 mg/mouse, respectively) and ANG II (1,000 ng·kg-1·min-1) for up to 14 days. Cardiac contractile function and structure were detected by echocardiography. Hypertrophy, fibrosis, and inflammation were assessed by histological examination. The infiltration of lymphocyte function-associated antigen-1 (LFA-1+) monocytes/macrophages was assessed by immunostaining. The mRNA expression of genes was evaluated by quantitative RT-PCR analysis. Protein levels were tested by immunoblotting. We found that ICAM-1 expression in ANG II-infused hearts and ICAM-1 levels in serum from human patients with heart failure were significantly increased. Moreover, ANG II infusion markedly enhanced ANG II-induced hypertension, caused cardiac contractile dysfunction, and promoted cardiac hypertrophy, fibrosis, and LFA-1+ macrophage infiltration. Conversely, blockage of ICAM-1 with a neutralizing antibody dose-dependently attenuated these effects. Moreover, our in vitro data further demonstrated that blocking ICAM-1 inhibited ANG II-induced LFA-1+ macrophage adhesion to endothelial cells and migration. In conclusion, these results provide novel evidence that blocking ICAM-1 exerts a protective effect in ANG II-induced cardiac remodeling at least in part through the modulation of adhesion and infiltration of LFA-1+ macrophages in the heart. Inhibition of ICAM-1 may represent a new therapeutic approach for hypertrophic heart diseases.NEW & NOTEWORTHY Leukocyte adhesion to vascular endothelium is a critical step in cardiovascular diseases. ICAM-1 is a member of immunoglobulin-like superfamily of adhesion molecules that binds LFA-1 to mediate leukocytes adhesion and migration. However, the significance of ICAM-1 in ANG II-induced cardiac remodeling remains unclear. This study reveals that blocking of ICAM-1 prevents ANG II-induced cardiac remodeling via modulating adhesion and migration of LFA-1+ monocytes, may serve as a novel therapeutic target for hypertensive cardiac diseases.