Sevoflurane blocks KLF5-mediated transcriptional activation of ITGB2 to inhibit macrophage infiltration in hepatic ischemia/reperfusion injury.

BACKGROUND: Sevoflurane (Sevo) preconditioning and postconditioning play a protective role against injury induced by hepatic ischemia/reperfusion (I/R). At the same time, the involvement of macrophage infiltration in this process and the precise mechanisms are unclear. Here, we designed this research to elucidate the protective effects of Sevo against hepatic I/R injury and the molecules involved. METHODS: The alleviating effect of Sevo on the liver injury was analyzed by liver function analysis, hematoxylin and eosin staining, Masson trichrome staining, terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate nick end labeling, western blot analysis and an enzyme-linked immunosorbent assay. An in vitro cell model was developed using alpha mouse liver 12 (AML12) cells, and the cell model was treated with oxygen-glucose deprivation and reoxygenation and Sevo. Multiple bioinformatics databases were used to screen transcriptional regulators related to hepatic I/R injury and the targets of Krueppel-like factor 5 (KLF5). KLF5 expression was artificially upregulated alone or with integrin beta-2 (ITGB2) knockdown to substantiate their involvement in Sevo-mediated hepatoprotection. RESULTS: Sevo protected the liver against I/R injury by reducing cell apoptosis and inflammatory response. KLF5 was upregulated in liver tissues following I/R injury, whereas KLF5 overexpression aggravated macrophage infiltration and liver injury induced by I/R injury. KLF5 bound to the promoter of ITGB2 to enhance ITGB2 transcription. Knockdown of ITGB2 reversed the aggravation of injury caused by KLF5 overexpression in mice and AML12 cells. CONCLUSIONS: Sevo blocked KLF5-mediated transcriptional activation of ITGB2, thereby inhibiting macrophage infiltration in hepatic I/R injury.

Dietary Iron Restriction Protects against Aneurysm Rupture in a Mouse Model of Intracranial Aneurysm.

INTRODUCTION: Iron accumulation in vessel walls induces oxidative stress and inflammation, which can cause cerebrovascular damage, vascular wall degeneration, and intracranial aneurysmal formation, growth, and rupture. Subarachnoid hemorrhage from intracranial aneurysm rupture results in significant morbidity and mortality. This study used a mouse model of intracranial aneurysm to evaluate the effect of dietary iron restriction on aneurysm formation and rupture. METHODS: Intracranial aneurysms were induced using deoxycorticosterone acetate-salt-induced hypertension and a single injection of elastase into the cerebrospinal fluid of the basal cistern. Mice were fed an iron-restricted diet (n = 23) or a normal diet (n = 25). Aneurysm rupture was detected by neurological symptoms, while the presence of intracranial aneurysm with subarachnoid hemorrhage was confirmed by post-mortem examination. RESULTS: The aneurysmal rupture rate was significantly lower in iron-restricted diet mice (37%) compared with normal diet mice (76%; p < 0.05). Serum oxidative stress, iron accumulation, macrophage infiltration, and 8-hydroxy-2'-deoxyguanosine in the vascular wall were lower in iron-restricted diet mice (p < 0.01). The areas of iron positivity were similar to the areas of CD68 positivity and 8-hydroxy-2'-deoxyguanosine in both normal diet and iron-restricted diet mouse aneurysms. CONCLUSIONS: These findings suggest that iron is involved in intracranial aneurysm rupture via vascular inflammation and oxidative stress. Dietary iron restriction may have a promising role in preventing intracranial aneurysm rupture.

Iguratimod prevents renal fibrosis in unilateral ureteral obstruction model mice by suppressing M2 macrophage infiltration and macrophage-myofibroblast transition.

Iguratimod is a novel synthetic, small-molecule immunosuppressive agent used to treat rheumatoid arthritis. Through ongoing exploration of its role and mechanisms of action, iguratimod has been observed to have antifibrotic effects in the lung and skin; however, its effect on renal fibrosis remains unknown. This study aimed to investigate whether iguratimod could affect renal fibrosis progression. Three different concentrations of iguratimod (30 mg/kg/day, 10 mg/kg/day, and 3 mg/kg/day) were used to intervene in unilateral ureteral obstruction (UUO) model mice. Iguratimod at 10 mg/kg/day was observed to be effective in slowing UUO-mediated renal fibrosis. In addition, stimulating bone marrow-derived macrophages with IL-4 and/or iguratimod, or with TGF-ß and iguratimod or SRC inhibitors in vitro, suggested that iguratimod mitigates the progression of renal fibrosis in UUO mice, at least in part, by inhibiting the IL-4/STAT6 signaling pathway to attenuate renal M2 macrophage infiltration, as well as by impeding SRC activation to reduce macrophage-myofibroblast transition. These findings reveal the potential of iguratimod as a treatment for renal disease.

Notch3 signaling promotes colorectal tumor growth by enhancing immunosuppressive cells infiltration in the microenvironment.

BACKGROUND: Macrophage infiltration in the tumor microenvironment participates in the regulation of tumor progression. Previous studies have found that Notch signaling pathway is involved in regulating the progression of colorectal cancer (CRC), however, the specific mechanism is still unclear. METHODS: The correlation between Notch signaling pathway and macrophage infiltration was investigated in TCGA database and verified in clinical samples of patients with CRC using immunohistochemistry. Gene Set Enrichment Analysis was used to find out genes related to Notch3 expression. Colony formation assay, and flow cytometry were utilized to test tumor growth and immune cell infiltration in vitro and in vivo. RESULTS: Using bioinformatics analysis and clinical sample validation, we found that Notch3 was highly expressed in colon tumor tissues compared to adjacent normal tissues, and it participated in regulating the recruitment of macrophages to the tumor microenvironment. Furthermore, we found that the Notch3 expression was positively correlated with the expression of macrophage recruitment-related cytokines in colon tumor tissues. Finally, we demonstrated that depletion of Notch3 had no significant effect on the growth of colon tumor cells in vitro, while, attenuated the growth of colon cancer tumors in vivo. Simultaneous, immunosuppressive cells, macrophages and myeloid-derived suppressor cell (MDSC) infiltration were dramatically reduced in the tumor microenvironment. CONCLUSION: Our study illustrated that Notch3 could facilitate the progression of CRC by increasing the infiltration of macrophages and MDSCs to promote the immunosuppressive tumor microenvironment. Targeting Notch3 specifically is a potentially effective treatment for CRC.

Alpinetin inhibits macrophage infiltration and atherosclerosis by improving the thiol redox state: Requirement of GSk3ß/Fyn-dependent Nrf2 activation.

Alpinetin is a plant flavonoid isolated from Alpinia katsumadai Hayata with antioxidant and anti-inflammatory properties. Monocyte infiltration into the intima promotes atherosclerotic development and causes plaque instability at the later stage, which is profoundly influenced by various oxidants. In this study, we investigated whether alpinetin restores the redox state to inhibit monocyte infiltration and ameliorates atherosclerosis. ApoE-deficient (ApoE-/- ) mice were fed a high-fat diet and treated with alpinetin. We found that alpinetin significantly attenuated atherosclerotic lesions and reduced necrotic core size associated with the reduction in infiltrated macrophages within the plaques. Alpinetin inhibited macrophage adhesion and migration, and the expression of chemokines and adhesion molecules, such as MCP-1, VCAM-1, and ICAM-1. Intraplaque MMP2 and MMP9 were reduced, while collagen contents were increased and elastin fiber was prevented from degradation in the alpinetin-treated mice. Data further showed that alpinetin reduced reactive oxygen species generation and promoted thiol-dependent glutathione and thioredoxin antioxidant systems in macrophages. Alpinetin activated Nfr2, an upstream activator of the thiol-dependent redox signaling by increasing the nuclear translocation. The nuclear accumulation of Nrf2 was enhanced by reducing nuclear export, which was achieved through the regulation of the GSk3ß/Fyn pathway. Finally, inhibition of Nrf2 in HFD-apoE-/- mice blockaded the effect of alpinetin, which increased aortic macrophage recruitment and aggravated atherosclerosis concurrently with elevating the expression of MCP-1, VCAM-1, and ICAM-1. Altogether, these findings indicated that alpinetin improved Nrf2-mediated redox homeostasis, which consequently inhibited macrophage infiltration and atherosclerosis, suggesting a useful compound for treating atherosclerosis.

VDUP1 Deficiency Promotes the Severity of DSS-Induced Colitis in Mice by Inducing Macrophage Infiltration.

The loss of vitamin D3 upregulated protein 1 (VDUP1) has been implicated in the pathogenesis of various inflammation-related diseases. Notably, reduced expression of VDUP1 has been observed in clinical specimens of ulcerative colitis (UC). However, the role of VDUP1 deficiency in colitis remains unclear. In this study, we investigated the role of VDUP1 in dextran sulfate sodium (DSS)-induced experimental colitis in mice. VDUP1-deficient mice were more susceptible to DSS-induced colitis than their wild-type (WT) littermates after 2% DSS administration. VDUP1-deficient mice exhibited an increased disease activity index (DAI) and histological scores, as well as significant colonic goblet cell loss and an increase in apoptotic cells. These changes were accompanied by a significant decrease in MUC2 mRNA expression and a marked increase in proinflammatory cytokines and chemokines within damaged tissues. Furthermore, phosphorylated NF-κB p65 expression was significantly upregulated in damaged tissues in the context of VDUP1 deficiency. VDUP1 deficiency also led to significant infiltration of macrophages into the site of ulceration. An in vitro chemotaxis assay confirmed that VDUP1 deficiency enhanced bone marrow-derived macrophage (BMDM) chemotaxis induced by CCL2. Overall, this study highlights VDUP1 as a regulator of UC pathogenesis and a potential target for the future development of therapeutic strategies.

Disulfiram Ophthalmic Solution Inhibited Macrophage Infiltration by Suppressing Macrophage Pseudopodia Formation in a Rat Corneal Alkali Burn Model.

FROUNT is an intracellular protein that promotes pseudopodia formation by binding to the chemokine receptors CCR2 and CCR5 on macrophages. Recently, disulfiram (DSF), a drug treatment for alcoholism, was found to have FROUNT inhibitory activity. In this study, we investigated the effect of DSF eye drops in a rat corneal alkali burn model. After alkali burn, 0.5% DSF eye drops (DSF group) and vehicle eye drops (Vehicle group) were administered twice daily. Immunohistochemical observations and real-time reverse transcription-polymerase chain reaction (RT-PCR) analyses were performed at 6 h and 1, 4, and 7 days after alkali burn. Results showed a significant decrease in macrophage accumulation in the cornea in the DSF group, but no difference in neutrophils. RT-PCR showed decreased expression of macrophage-associated cytokines in the DSF group. Corneal scarring and neovascularization were also suppressed in the DSF group. Low-vacuum scanning electron microscopy imaging showed that macrophage length was significantly shorter in the DSF group, reflecting the reduced extension of pseudopodia. These results suggest that DSF inhibited macrophage infiltration by suppressing macrophage pseudopodia formation.

Different expressions of aquaporin water channels and macrophages infiltration in human cervix remodeling during pregnancy.

Despite aquaporin water channels (AQPs) play a critical role in maintaining water homeostasis in female reproductive tract and prompt a gradual increase in water content in cervical edema as pregnancy progressed, their relationship with macrophage infiltration and collagen content in human cervical remodeling need to be further investigated. This is the first study to examine the expression and localization of AQP3, AQP4, AQP5, AQP8, and macrophages simultaneously in human cervical ripening. The immunoreactivity of these AQPs was 2.6 to 6-fold higher on gestational weeks 26 (GD26W) than that on GD6W and GD15W, but AQP4 expression on GD39W dropped a similar extent on GD15W, other AQPs continued to rise on GD39W. The AQP3, AQP4, and AQP5 intensity seemed more abundant in cervical stroma than in the perivascular area on GD26W; the distribution of AQP3, AQP5, and AQP8 in cervical stroma was equivalent to that in the perivascular area on GD39W. Macrophage numbers were 1.7-fold higher in subepithelium region and 3.0-fold higher in center area on GD26W than that on GD15W; such numbers remained elevated on GD39W. The electron micrographs showed that cervical extensibility increased significantly on GD26W and GD39W accompanied with increased macrophage infiltration, cervical water content, and much more space among collagen fibers. These findings suggest that the upregulation of AQPs expression in human cervix is closely related to enhanced macrophage infiltration during pregnancy; there may be a positive feedback mechanism between them to lead the increase of water content and the degradation of collagen.

A Novel Knitted Polytetrafluoroethylene Patch for Cardiovascular Surgery.

Polytetrafluoroethylene (PTFE) is widely used in cardiovascular surgeries; however, postoperative complications such as thrombosis, calcification, and neointimal hyperplasia are yet to be resolved in patients. We developed two types of novel knitted PTFE patches and evaluated them using a swine model. Both patches were composed of knitted PTFE impregnated with micro-PTFE particles, and one of them was pressed after PTFE impregnation. Twenty micromini pigs were used in this study. After left lateral thoracotomy, the new patches (n = 8 for each type of patch) were implanted into the descending aorta and left atrium for the high- and low-pressure models, respectively. Clinically used expanded PTFE (ePTFE) patches were used as the control material (n = 4). The patches were explanted and histopathologically examined at 4, 12, and 24 weeks after implantation. A tensile test was also applied to the high-pressure model at 12 and 24 weeks. As a result, there was no significant difference noted in the tensile test, intimal hyperplasia thickness, or endothelialization among the three patches. In contrast, the degree of macrophage infiltration into the patches and the degree of macrophage, lymphocyte, and granulocyte infiltration outside the patches were lower in the new patches than in the control ePTFE. The degree of cellular infiltration outside new patches decreased over time. There were no significant differences between the two new patch types in these results. In conclusion, our novel knitted PTFE patch showed noninferiority in durability and intensity and less inflammatory responses than a clinically used ePTFE patch.

Chronic AT1 blockade improves hyperglycemia by decreasing adipocyte inflammation and decreasing hepatic PCK1 and G6PC1 expression in obese rats.

Inappropriate activation of the renin-angiotensin system decreases glucose uptake in peripheral tissues. Chronic angiotensin receptor type 1 (AT1) blockade (ARB) increases glucose uptake in skeletal muscle and decreases the abundance of large adipocytes and macrophage infiltration in adipose. However, the contributions of each tissue to the improvement in hyperglycemia in response to AT1 blockade are not known. Therefore, we determined the static and dynamic responses of soleus muscle, liver, and adipose to an acute glucose challenge following the chronic blockade of AT1. We measured adipocyte morphology along with TNF-α expression, F4/80- and CD11c-positive cells in adipose and measured insulin receptor (IR) phosphorylation and AKT phosphorylation in soleus muscle, liver, and retroperitoneal fat before (T0), 60 (T60) and 120 (T120) min after an acute glucose challenge in the following groups of male rats: 1) Long-Evans Tokushima Otsuka (LETO; lean control; n = 5/time point), 2) obese Otsuka Long Evans Tokushima Fatty (OLETF; n = 7 or 8/time point), and 3) OLETF + ARB (ARB; 10 mg olmesartan/kg/day; n = 7 or 8/time point). AT1 blockade decreased adipocyte TNF-α expression and F4/80- and CD11c-positive cells. In retroperitoneal fat at T60, IR phosphorylation was 155% greater in ARB than in OLETF. Furthermore, in retroperitoneal fat AT1 blockade increased glucose transporter-4 (GLUT4) protein expression in ARB compared with OLETF. IR phosphorylation and AKT phosphorylation were not altered in the liver of OLETF, but AT1 blockade decreased hepatic Pck1 and G6pc1 mRNA expressions. Collectively, these results suggest that chronic AT1 blockade improves obesity-associated hyperglycemia in OLETF rats by improving adipocyte function and by decreasing hepatic glucose production via gluconeogenesis.NEW & NOTEWORTHY Inappropriate activation of the renin-angiotensin system increases adipocyte inflammation contributing to the impairment in adipocyte function and increases hepatic Pck1 and G6pc1 mRNA expression in response to a glucose challenge. Ultimately, these effects may contribute to the development of glucose intolerance.

Recombinant sulfated CCR2 peptide trap reduces retinal degeneration in mice.

Chemokine receptors are generally sulfated at tyrosine residues of the N-terminal region. Tyrosine sulfation of the C-C chemokine receptor type 2 (CCR2) enhances its interaction with the chemokine ligand CCL2. Here, we generated a recombinant sulfated CCR2 peptide trap (mCCR2-S2) and investigated its effects on retinal degeneration in mice. Treatment with mCCR2-S2 reduced choroidal neovascularization (CNV) in a laser-induced CNV mouse model. In NaIO3-injected mice, treatment with mCCR2-S2 increased the outer nuclear layer thickness and rhodopsin expression in the retinas compared to that in mice treated with mCCR2-wild-type or glutathione S-transferase controls. Furthermore, glial fibrillary acidic protein (GFAP) expression and macrophage infiltration were decreased in mCCR2-S2-treated retinas. Recombinant mCCR2-S2 suppressed CNV development and retinal degeneration, possibly by regulating macrophage infiltration. Thus, the sulfated form of the CCR2 peptide trap may be a useful tool for treating patients with retinal degeneration, such as those with age-related macular degeneration and intraocular inflammatory disorders.

H2S alleviates renal injury and fibrosis in response to unilateral ureteral obstruction by regulating macrophage infiltration via inhibition of NLRP3 signaling.

Renal fibrosis is a key pathological feature in chronic kidney diseases (CKDs). Dysregulation of hydrogen sulfide (H2S) homeostasis is implicated in the pathogenesis of CKDs. Here, C57/BL6 mice were allocated to Sham and unilateral ureteral obstruction (UUO) groups, which were treated with NaHS or NLRP3 inflammasome inhibitor 16673-34-0 for 3-14 days. UUO mice displayed downregulation of H2S production and increased macrophage infiltration in obstructed kidneys. H2S donor NaHS treatment attenuated renal damage and fibrosis and inhibited M1 and M2 macrophage infiltration. NLPR3 inflammasome was activated and levels of phosphorylated nuclear factor κB (NF-κB) p65 subunit, phosphorylated signal transducer and activator of transcription 6 (STAT6) and interleukin (IL)-4 protein were increased in the kidneys after UUO. NLRP3 inhibitor inactivated NF-κB and IL-4/STAT6 signaling, suppressed M1 and M2 macrophage infiltration and attenuated renal damage and fibrosis in UUO mice. NaHS treatment also suppressed NLRP3, NF-κB and IL-4/STAT6 activation in the obstructed kidneys. In conclusion, the therapeutic effects of H2S on UUO-induced renal injury and fibrosis are at least in part by inhibition of M1 and M2 macrophage infiltration. H2S suppresses NLRP3 activation and subsequently inactivates NF-κB and IL-4/STAT6 signaling, which may contribute to the anti-inflammatory and anti-fibrotic effects of H2S.

Both HuR and miR-29s regulate expression of CB1 involved in infiltration of bone marrow monocyte/macrophage in chronic liver injury.

Bone marrow-derived monocytes/macrophages (BMMs) play a vital role in liver inflammation and fibrogenesis. Cannabinoid receptor 1 (CB1) mediates the recruitment of BMMs into the injured liver. In this study, we revealed the molecular mechanisms under CB1-mediated BMM infiltration. Carbon tetrachloride (CCl4 ) was employed to induce mouse liver injury. In vivo, human antigen R (HuR) was upregulated in macrophages of injured liver. HuR messenger RNA (mRNA) expression was positively correlated with CB1 and F4/80 mRNA expression. Furthermore, we detected the binding between HuR and CB1 mRNA in CCl4 -treated livers. In vitro, HuR modulated arachidonyl-2'-chloroethylamide (ACEA, CB1 agonist)-induced BMM migration by regulating CB1 expression. HuR promoted CB1 expression via binding to CB1 mRNA. ACEA promoted the association between HuR and CB1 mRNA via inducing HuR nucleoplasmic transport. In the cytoplasm, HuR competed with the miR-29 family to improve CB1 expression and BMM migration. In conclusion, our results prove that HuR regulates CB1 expression and influences ACEA-induced BMM migration by competing with miR-29 family.

Disruption of dystonin in Schwann cells results in late-onset neuropathy and sensory ataxia.

Dystonin (Dst) is a causative gene for Dystonia musculorum (dt) mice, which is an inherited disorder exhibiting dystonia-like movement and ataxia with sensory degeneration. Dst is expressed in a variety of tissues, including the central nervous system and the peripheral nervous system (PNS), muscles, and skin. However, the Dst-expressing cell type(s) for dt phenotypes have not been well characterized. To address the questions whether the disruption of Dst in Schwann cells induces movement disorders and how much impact does it have on dt phenotypes, we generated Dst conditional knockout (cKO) mice using P0-Cre transgenic mice and Dst gene trap mice. First, we assessed the P0-Cre transgene-dependent Cre recombination using tdTomato reporter mice and then confirmed the preferential tdTomato expression in Schwann cells. In the Dst cKO mice, Dst mRNA expression was significantly decreased in Schwann cells, but it was intact in most of the sensory neurons in the dorsal root ganglion. Next, we analyzed the phenotype of Dst cKO mice. They exhibited a normal motor phenotype during juvenile periods, and thereafter, started exhibiting an ataxia. Behavioral tests and electrophysiological analyses demonstrated impaired motor abilities and slowed motor nerve conduction velocity in Dst cKO mice, but these mice did not manifest dystonic movements. Electron microscopic observation of the PNS of Dst cKO mice revealed significant numbers of hypomyelinated axons and numerous infiltrating macrophages engulfing myelin debris. These results indicate that Dst is important for normal PNS myelin organization and Dst disruption in Schwann cells induces late-onset neuropathy and sensory ataxia. MAIN POINTS: Dystonin (Dst) disruption in Schwann cells results in late-onset neuropathy and sensory ataxia. Dst in Schwann cells is important for normal myelin organization in the peripheral nervous system.

Long-term hypercortisolism induces lipogenesis promoting palmitic acid accumulation and inflammation in visceral adipose tissue compared with HFD-induced obesity.

Glucocorticoids (GCs) play critical roles in adipose tissue metabolism. Here, we compare in a mouse model the effects of chronic glucocorticoid excess and diet-induced obesity on white adipose tissue mass and distribution, by focusing on visceral adipose tissue (VAT) fatty acid composition changes, the role of de novo lipogenesis (DNL) and the inflammatory state. We used a noninvasive mouse model of hypercortisolism to compare GC-induced effects on adipose tissue with diet-induced obesity [high-fat diet (HFD) 45%] and control mice after 10 wk of treatment. Subcutaneous adipose tissue (SAT) and VAT mass and distribution were measured by nuclear magnetic resonance imaging (NMRI). Fatty acid composition in VAT was analyzed by NMR spectroscopy and gas chromatography. Gene expression of key enzymes involved in DNL was analyzed in liver and VAT. Macrophage infiltration markers and proinflammatory cytokines were measured by gene expression in VAT. HFD or GC treatment induced similar fat mass expansion with comparable distribution between SAT and VAT depots. However, in VAT, GCs induce DNL, higher palmitic acid (PA), macrophage infiltration, and proinflammatory cytokine levels, accompanied by systemic nonesterified fatty acid (NEFA) elevation, hyperinsulinemia, and higher homeostatic model assessment for insulin resistance (HOMA-IR) levels compared with diet-induced obesity. Thus, chronic hypercortisolism induces DNL and fatty acid composition changes toward increased SFA and reduced polyunsaturated fatty acid (PUFA) levels in VAT, promoting macrophage recruitment and proinflammatory cytokines, suggesting a worse cardiometabolic profile even compared with HFD mice.

A novel salviadione derivative, compound 15a, attenuates diabetes-induced renal injury by inhibiting NF-κB-mediated inflammatory responses.

Diabetic nephropathy is the leading cause of renal failure worldwide. Elevated inflammatory signaling has been shown to lead to deterioration of renal function in human and experimental diabetes. We recently developed a salviadione derivative (compound 15a) that prevented microbial lipopolysaccharide-induced inflammatory responses, which are largely driven by nuclear factor-κB (NF-κB). In the present study, we have tested the hypothesis that 15a will protect kidneys from diabetes-induced dysfunction by suppressing NF-κB activation and inflammatory signaling. Treatment of diabetic mice with 15a inhibited diabetes-induced renal fibrosis, NF-κB activation, and upregulation of proinflammatory cytokines. Histologically, kidney specimens from diabetic mice treated with 15a were indistinguishable from non-diabetic controls. We confirmed our findings in cultured renal tubular epithelial cells exposed to high levels of glucose. In these cultured cells, 15a pretreatment prevented high glucose-induced NF-κB activation and expression of inflammatory cytokines. These protective effects were also reflected in reduced levels of proteins involved in matrix expansion. Overall, our studies show that a salviadione derivative, 15a, is effective in suppressing diabetes-induced NF-κB activation and inflammatory signaling.

Astrocyte-targeted IL-10 production decreases proliferation and induces a downregulation of activated microglia/macrophages after PPT.

When central nervous system (CNS) homeostasis is altered, microglial cells become rapidly activated, proliferate and release a broad range of molecules. Among the plethora of molecules involved in the regulation of microglial activation, cytokines are considered crucial. Although production of interleukin-10 (IL-10) has been demonstrated after different types of CNS injuries and associated with protective functions, the specific role played by IL-10 modulating microglial cells remains unclear. Hence, the objective of this study was to evaluate the effects of transgenic astrocyte IL-10 production on microglial activation associated with axonal anterograde degeneration. To address it, the hippocampal area subjected to perforant pathway transection (PPT) was analyzed by immunohistochemistry (IHC), flow cytometry and protein microarray in transgenic (GFAP-IL10Tg) mice and their corresponding wild types (WT) littermates. Our results demonstrated increased microglial/macrophages density in nonlesioned and PPT-lesioned GFAP-IL10Tg animals when compared with nonlesioned and lesioned WT, respectively. This increase was not due to proliferation, as GFAP-IL10Tg mice showed a reduced proliferation of microglial cells, but was related to an increased population of CD11b+/CD45high monocyte/macrophages. Despite this higher number, the microglia/macrophage population in transgenic animals displayed a downregulated phenotype characterized by lower MHCII, ICOSL, and CD11c. Moreover, a sustained T-cell infiltration was found in transgenic animals. We strongly suggest these modifications must be associated with indirect effects derived from the influence of IL-10 on astrocytes and/or neurons, which express IL-10R. We finally suggested that TGF-ß produced by astrocytes, along with IL-2 and CXCL10 might be crucial molecules mediating the effects of transgenic IL-10.

Bone marrow stromal cells transplantation promotes the resolution and recanalization of deep vein thrombosis in rabbits through regulating macrophage infiltration and angiogenesis.

This study aims to validate whether bone marrow stromal cells (BMSCs) transplantation could promote the resolution and recanalization of deep vein thrombosis (DVT) and to explore the underlying mechanism. The right hind femoral vein was embolized to establish the DVT rabbit model. BMSCs from New Zealand white rabbits were isolated and identified, and then injected into DVT rabbits. After that, the extent of angiogenesis was determined by the amount of capillaries that were positive for antibody against vWF. Macrophage infiltration was measured by immunohistochemistry with F4/80 antibody. M1 or M2 macrophages were identified as F4/80 + CD11c + or F4/80 + CD206 + cells by using flow cytometry analysis, respectively. BMSCs were successfully isolated and identified. BMSCs transplantation promotes macrophage infiltration and angiogenesis in DVT rabbits. BMSCs transplantation causes M1/M2 polarization, altered cytokine production and increased monocyte chemotactic protein 1 (MCP-1) protein expression in DVT rabbits. However, injection of MCP-1 protein not only reversed the effects of BMSCs transplantation on macrophage infiltration and angiogenesis, but also reversed the effects of BMSCs transplantation on M1/M2 polarization and cytokine production in DVT rabbits. BMSCs transplantation promotes the resolution and recanalization of DVT in rabbits through regulating macrophage infiltration and angiogenesis, the underlying mechanism is associated with MCP-1 expression.

Adipocyte SIRT1 controls systemic insulin sensitivity by modulating macrophages in adipose tissue.

Adipose tissue inflammation, characterized by augmented infiltration and altered polarization of macrophages, contributes to insulin resistance and its associated metabolic diseases. The NAD+-dependent deacetylase SIRT1 serves as a guardian against metabolic disorders in multiple tissues. To dissect the roles of SIRT1 in adipose tissues, metabolic phenotypes of mice with selective ablation of SIRT1 in adipocytes and myeloid cells were monitored. Compared to myeloid-specific SIRT1 depletion, mice with adipocyte-selective deletion of SIRT1 are more susceptible to diet-induced insulin resistance. The phenotypic changes in adipocyte-selective SIRT1 knockout mice are associated with an increased number of adipose-resident macrophages and their polarization toward the pro-inflammatory M1 subtype. Mechanistically, SIRT1 in adipocytes modulates expression and secretion of several adipokines, including adiponectin, MCP-1, and interleukin 4, which in turn alters recruitment and polarization of the macrophages in adipose tissues. In adipocytes, SIRT1 deacetylates the transcription factor NFATc1 and thereby enhances the binding of NFATc1 to the Il4 gene promoter. These findings suggest that adipocyte SIRT1 controls systemic glucose homeostasis and insulin sensitivity via the cross talk with adipose-resident macrophages.

Early interstitial macrophage infiltration with mild dysfunction is associated with subsequent kidney graft loss.

Macrophage infiltration is associated with unfavorable kidney graft outcome in protocol biopsies, but few studies have evaluated its impact on clinical practice. We therefore prospectively evaluated 37 kidney transplant recipients (KTRs) who underwent kidney biopsy due to slight increases in serum creatinine, or mild proteinuria (>0.3 g/24 hr), in the first post-transplant year. Banff score, CD68+ count (score 0-3) by immunohistochemistry, and 1-year DSA were assessed. DGF was reported in 10 (27%) patients, 6 (16%) had normal biopsy, 7 (19%) borderline lesions, 13 (35%) IFTA, and 11 (30%) other lesions. Fifteen KTRs had grade 3 CD68+ infiltration, and 47% developed de novo DSA. During a 6.2 ± 2.7 year follow-up, four patients (11%) suffered from biopsy-proven T-cell rejection, 17 KTRs (46%) lost their graft (12 in the grade 3 CD68+ group). Graft survival was lower in KTRs with grade 3 CD68+ infiltration (P = 0.0074; log-rank test). Grade 3 CD68+ infiltrate was an independent predictor of graft loss (HR 5.41, 95% CI 1.74-16.8; P = 0.003), together with more severe graft dysfunction at biopsy (HR 6.41, 95% CI 2.57-16; P < 0.001). We conclude that grade 3 CD68+ interstitial infiltration is associated with increased risk of subsequent graft loss independent of other factors.