Macrophage-specific gene expression: current paradigms and future challenges

Exosomes derived from vMIP-II-Lamp2b gene-modified M2 cells provide neuroprotection by targeting the injured spinal cord, inhibiting chemokine signals and modulating microglia/macrophage polarization in mice

Inflammation is one of the key injury factors for spinal cord injury (SCI). Exosomes (Exos) derived from M2 macrophages have been shown to inhibit inflammation and be beneficial in SCI animal models. However, lacking targetability restricts their application prospects. Considering that chemokine receptors increase dramatically after SCI, viral macrophage inflammatory protein II (vMIP-II) is a broad-spectrum chemokine receptor binding peptide, and lysosomal associated membrane protein 2b (Lamp2b) is the key membrane component of Exos, we speculated that vMIP-II-Lamp2b gene-modified M2 macrophage-derived Exos (vMIP-II-Lamp2b-M2-Exo) not only have anti-inflammatory properties, but also can target the injured area by vMIP-II. In this study, using a murine contusive SCI model, we revealed that vMIP-II-Lamp2b-M2-Exo could target the chemokine receptors which highly expressed in the injured spinal cords, inhibit some key chemokine receptor signaling pathways (such as MAPK and Akt), further inhibit proinflammatory factors (such as IL-1β, IL-6, IL-17, IL-18, TNF-α, and iNOS), and promote anti-inflammatory factors (such as IL-4 and Arg1) productions, and the transformation of microglia/macrophages from M1 into M2. Moreover, the improved histological and functional recoveries were also found. Collectively, our results suggest that vMIP-II-Lamp2b-M2-Exo may provide neuroprotection by targeting the injured spinal cord, inhibiting some chemokine signals, reducing proinflammatory factor production and modulating microglia/macrophage polarization.

Neither injury induced macrophages within the nerve, nor the environment created by Wallerian degeneration is necessary for enhanced in vivo axon regeneration after peripheral nerve injury

BACKGROUND

Since the 1990s, evidence has accumulated that macrophages promote peripheral nerve regeneration and are required for enhancing regeneration in the conditioning lesion (CL) response. After a sciatic nerve injury, macrophages accumulate in the injury site, the nerve distal to that site, and the axotomized dorsal root ganglia (DRGs). In the peripheral nervous system, as in other tissues, the macrophage response is derived from both resident macrophages and recruited monocyte-derived macrophages (MDMs). Unresolved questions are: at which sites do macrophages enhance nerve regeneration, and is a particular population needed.

METHODS

Ccr2 knock-out (KO) and Ccr2gfp/gfp knock-in/KO mice were used to prevent MDM recruitment. Using these strains in a sciatic CL paradigm, we examined the necessity of MDMs and residents for CL-enhanced regeneration in vivo and characterized injury-induced nerve inflammation. CL paradigm variants, including the addition of pharmacological macrophage depletion methods, tested the role of various macrophage populations in initiating or sustaining the CL response. In vivo regeneration, measured from bilateral proximal test lesions (TLs) after 2 d, and macrophages were quantified by immunofluorescent staining.

RESULTS

Peripheral CL-enhanced regeneration was equivalent between crush and transection CLs and was sustained for 28 days in both Ccr2 KO and WT mice despite MDM depletion. Similarly, the central CL response measured in dorsal roots was unchanged in Ccr2 KO mice. Macrophages at both the TL and CL, but not between them, stained for the pro-regenerative marker, arginase 1. TL macrophages were primarily CCR2-dependent MDMs and nearly absent in Ccr2 KO and Ccr2gfp/gfp KO mice. However, there were only slightly fewer Arg1+ macrophages in CCR2 null CLs than controls due to resident macrophage compensation. Zymosan injection into an intact WT sciatic nerve recruited Arg1+ macrophages but did not enhance regeneration. Finally, clodronate injection into Ccr2gfp KO CLs dramatically reduced CL macrophages. Combined with the Ccr2gfp KO background, depleting MDMs and TL macrophages, and a transection CL, physically removing the distal nerve environment, nearly all macrophages in the nerve were removed, yet CL-enhanced regeneration was not impaired.

CONCLUSIONS

Macrophages in the sciatic nerve are neither necessary nor sufficient to produce a CL response.

History of Microglia

The term 'microglia' was first introduced into the scientific literature a century ago. The various eras of microglial research have been defined not only by the number of reports subsequently generated but, more critically, also by the concepts that have shaped our present-day views and understanding of microglia. Key methods, technologies, and models, as well as seminal discoveries made possible through their deployment have enabled breakthroughs, and now pave the way for lines of investigation that could not have been anticipated even a decade ago. Advances in our understanding of the microglial origin, forms, and functions have relied fundamentally on parallel developments in immunology. As the 'neuro-immune' cells of the brain, microglia are now under the spotlight in various disciplines. This chapter surveys the gradual processes and precipitous events that helped form ideas concerning the developmental origin of microglia and their roles in health and disease. It first covers the dawning phase during which the early pioneers of microglial research discovered cellular entities and already assigned functions to them. Following a recess period, the 1960s brought about a renaissance of active interest, with the development of tools and models-and fundamental notions on microglial contributions to central nervous system (CNS) pathologies. These seminal efforts laid the foundation for the awakening of a sweeping research era beginning in the 1980s and spurred on by a blast of immunological discoveries. Finally, this chapter stresses the advancements in molecular, genetic, and imaging approaches to the study of microglia with the turn of the millennium, enabling insights into virtually all facets of microglial physiology. Moving forward, it is clear that the future holds substantial promise for further discoveries. The next epoch in the history of microglial research has just begun.

Droplet Digital PCR Is a Novel Screening Method Identifying Potential Cardiac G-Protein-Coupled Receptors as Candidate Pharmacological Targets in a Rat Model of Pressure-Overload-Induced Cardiac Dysfunction

The identification of novel drug targets is needed to improve the outcomes of heart failure (HF). G-protein-coupled receptors (GPCRs) represent the largest family of targets for already approved drugs, thus providing an opportunity for drug repurposing. Here, we aimed (i) to investigate the differential expressions of 288 cardiac GPCRs via droplet digital PCR (ddPCR) and bulk RNA sequencing (RNAseq) in a rat model of left ventricular pressure-overload; (ii) to compare RNAseq findings with those of ddPCR; and (iii) to screen and test for novel, translatable GPCR drug targets in HF. Male Wistar rats subjected to transverse aortic constriction (TAC, n = 5) showed significant systolic dysfunction vs. sham operated animals (SHAM, n = 5) via echocardiography. In TAC vs. SHAM hearts, RNAseq identified 69, and ddPCR identified 27 significantly differentially expressed GPCR mRNAs, 8 of which were identified using both methods, thus showing a correlation between the two methods. Of these, Prostaglandin-F2α-receptor (Ptgfr) was further investigated and localized on cardiomyocytes and fibroblasts in murine hearts via RNA-Scope. Antagonizing Ptgfr via AL-8810 reverted angiotensin-II-induced cardiomyocyte hypertrophy in vitro. In conclusion, using ddPCR as a novel screening method, we were able to identify GPCR targets in HF. We also show that the antagonism of Ptgfr could be a novel target in HF by alleviating cardiomyocyte hypertrophy.

Age-related neuroimmune signatures in dorsal root ganglia of a Fabry disease mouse model

Pain in Fabry disease (FD) is generally accepted to result from neuronal damage in the peripheral nervous system as a consequence of excess lipid storage caused by alpha-galactosidase A (α-Gal A) deficiency. Signatures of pain arising from nerve injuries are generally associated with changes of number, location and phenotypes of immune cells within dorsal root ganglia (DRG). However, the neuroimmune processes in the DRG linked to accumulating glycosphingolipids in Fabry disease are insufficiently understood.Therefore, using indirect immune fluorescence microscopy, transmigration assays and FACS together with transcriptomic signatures associated with immune processes, we assessed age-dependent neuroimmune alterations in DRG obtained from mice with a global depletion of α-Gal A as a valid mouse model for FD. Macrophage numbers in the DRG of FD mice were unaltered, and BV-2 cells as a model for monocytic cells did not show augmented migratory reactions to glycosphingolipids exposure suggesting that these do not act as chemoattractants in FD. However, we found pronounced alterations of lysosomal signatures in sensory neurons and of macrophage morphology and phenotypes in FD DRG. Macrophages exhibited reduced morphological complexity indicated by a smaller number of ramifications and more rounded shape, which were age dependent and indicative of premature monocytic aging together with upregulated expression of markers CD68 and CD163.In our FD mouse model, the observed phenotypic changes in myeloid cell populations of the DRG suggest enhanced phagocytic and unaltered proliferative capacity of macrophages as compared to wildtype control mice. We suggest that macrophages may participate in FD pathogenesis and targeting macrophages at an early stage of FD may offer new treatment options other than enzyme replacement therapy.

The polarization of microglia and infiltrated macrophages in the injured mice spinal cords: a dynamic analysis

Background

Following spinal cord injury (SCI), a large number of peripheral monocytes infiltrate into the lesion area and differentiate into macrophages (Mø). These monocyte-derived Mø are very difficult to distinguish from the local activated microglia (MG). Therefore, the term Mø/MG are often used to define the infiltrated Mø and/or activated MG. It has been recognized that pro-inflammatory M1-type Mø/MG play "bad" roles in the SCI pathology. Our recent research showed that local M1 cells are mainly CD45^-/lowCD68⁺CD11b⁺ in the subacute stage of SCI. Thus, we speculated that the M1 cells in injured spinal cords mainly derived from MG rather than infiltrating Mø. So far, their dynamics following SCI are not yet entirely clear.

Methods

Female C57BL/6 mice were used to establish SCI model, using an Infinite Horizon impactor with a 1.3 mm diameter rod and a 50 Kdynes force. Sham-operated (sham) mice only underwent laminectomy without contusion. Flow cytometry and immunohistofluorescence were combined to analyze the dynamic changes of polarized Mø and MG in the acute (1 day), subacute (3, 7 and 14 days) and chronic (21 and 28 days) phases of SCI.

Results

The total Mø/MG gradually increased and peaked at 7 days post-injury (dpi), and maintained at high levels 14, 21 and 28 dpi. Most of the Mø/MG were activated, and the Mø increased significantly at 1 and 3 dpi. However, with the pathological process, activated MG increased nearly to 90% at 7, 14, 21 and 28 dpi. Both M1 and M2 Mø were increased significantly at 1 and 3 dpi. However, they decreased to very low levels from 7 to 28 dpi. On the contrary, the M2-type MG decreased significantly following SCI and maintained at a low level during the pathological process.

Molecular Characterization, Expression, Evolutionary Selection, and Biological Activity Analysis of CD68 Gene from Megalobrama amblycephala

CD68 is a highly glycosylated transmembrane glycoprotein that belongs to the lysosome-associated membrane glycoprotein family and is involved in various immune processes. In this study, Megalobrama amblycephala CD68 (MaCD68) was cloned and characterized, and its expression patterns and evolutionary characteristics were analyzed. The coding region of MaCD68 was 987 bp, encoding 328 amino acids, and the predicted protein molecular weight was 34.9 kDa. MaCD68 contained two transmembrane helical structures and 18 predicted N-glycosylation sites. Multiple sequence alignments showed that the MaCD68 protein had high homology with other fish, and their functional sites were also highly conserved. Phylogenetic analysis revealed that MaCD68 and other cypriniformes fish clustered into one branch. Adaptive evolution analysis identified several positively selected sites of teleost CD68 using site and branch-site models, indicating that it was under positive selection pressure during evolution. Quantitative real-time reverse transcription polymerase chain reaction analysis showed that MaCD68 was highly expressed in the head kidney, spleen, and heart. After Aeromonas hydrophila infection, MaCD68 was significantly upregulated in all tested tissues, peaking at 12 h post-infection (hpi) in the kidney and head kidney and at 120 hpi in the liver and spleen, suggesting that MaCD68 participated in the innate immune response of the host against bacterial infection. Immunohistochemical and immunofluorescence analyses also showed that positive signals derived from the MaCD68 protein were further enhanced after bacterial and lipopolysaccharide treatment, which suggested that MaCD68 is involved in the immune response and could be used as a macrophage marker. Biological activity analysis indicated that recombinant MaCD68 (rMaCD68) protein had no agglutination or bactericidal effects on A. hydrophila but did have these effects on Escherichia coli. In conclusion, these results suggest that MaCD68 plays a vital role in the immune response against pathogens, which is helpful in understanding the immune responses and mechanisms of M. amblycephala.

Saxagliptin Cardiotoxicity in Chronic Heart Failure: The Role of DPP4 in the Regulation of Neuropeptide Tone

Dipeptidyl-peptidase-4 (DPP4) inhibitors are novel medicines for diabetes. The SAVOR-TIMI-53 clinical trial revealed increased heart-failure-associated hospitalization in saxagliptin-treated patients. Although this side effect could limit therapeutic use, the mechanism of this potential cardiotoxicity is unclear. We aimed to establish a cellular platform to investigate DPP4 inhibition and the role of its neuropeptide substrates substance P (SP) and neuropeptide Y (NPY), and to determine the expression of DDP4 and its neuropeptide substrates in the human heart. Western blot, radio-, enzyme-linked immuno-, and RNA scope assays were performed to investigate the expression of DPP4 and its substrates in human hearts. Calcein-based viability measurements and scratch assays were used to test the potential toxicity of DPP4 inhibitors. Cardiac expression of DPP4 and NPY decreased in heart failure patients. In human hearts, DPP4 mRNA is detectable mainly in cardiomyocytes and endothelium. Treatment with DPP4 inhibitors alone/in combination with neuropeptides did not affect viability but in scratch assays neuropeptides decreased, while saxagliptin co-administration increased fibroblast migration in isolated neonatal rat cardiomyocyte-fibroblast co-culture. Decreased DPP4 activity takes part in the pathophysiology of end-stage heart failure. DPP4 compensates against the elevated sympathetic activity and altered neuropeptide tone. Its inhibition decreases this adaptive mechanism, thereby exacerbating myocardial damage.

Identification of macrophage related gene in colorectal cancer patients and their functional roles

BACKGROUND

Recent scientific research has enabled the identification of macrophages related-genes (MaRG), which play a key role in the control of the immune microenvironment in many human cancers. However, the functional role of MaRGs in human tumors is ill-defined. Herein, we aimed at bioinformatically exploring the molecular signatures of MaRGs in colorectal cancer.

METHODS

A list of MaRGs was generated and their differential expression was analyzed across multiple datasets downloaded from the publicly available functional genomics database Gene Expression Omnibus. The weighted gene co-expression network analysis (WGCNA) was also applied to identify the partner genes of these MaRGs in colorectal cancer.

RESULTS

After integration of the results from analyses of different datasets, we found that 29 differentially expressed MaRGs (DE-MaRGs) could be considered as CRC-related genes as obtained from the WGCNA analysis. These genes were functionally involved in positive regulation of DNA biosynthetic process and glutathione metabolism. Protein-protein interaction network analysis indicated that PDIA6, PSMA1, PRC1, RRM2, HSP90AB1, CDK4, MCM7, RFC4, and CCT5 were the hub MaRGs. The LASSO approach was used for validating the 29 MaRGs in TCGA-COAD and TCGA-READ data and the results showed that ten among the 29 genes could be considered as MaRGs significantly involved in CRC. The maftools analysis showed that MaRGs were mutated at varying degrees. The nomogram analysis indicated the correlation of these MaRGs with diverse clinical features of CRC patients.

CONCLUSIONS

Conclusively, the present disclosed a signature of MaRGs as potential key regulators involved in CRC pathogenesis and progression. These findings contribute not only to the understanding of the molecular mechanism of CRC pathogenesis but also to the development of adequate immunotherapies for CRC patients.

The role of epigenetic modifications for the pathogenesis of Crohn's disease

Epigenetics has become a promising field for finding new biomarkers and improving diagnosis, prognosis, and drug response in inflammatory bowel disease. The number of people suffering from inflammatory bowel diseases, especially Crohn's disease, has increased remarkably. Crohn's disease is assumed to be the result of a complex interplay between genetic susceptibility, environmental factors, and altered intestinal microbiota, leading to dysregulation of the innate and adaptive immune response. While many genetic variants have been identified to be associated with Crohn's disease, less is known about the influence of epigenetics in the pathogenesis of this disease. In this review, we provide an overview of current epigenetic studies in Crohn's disease. In particular, we enable a deeper insight into applied bioanalytical and computational tools, as well as a comprehensive update toward the cell-specific evaluation of DNA methylation and histone modifications.

Spatial mapping of SARS-CoV-2 and H1N1 lung injury identifies differential transcriptional signatures

Severe SARS-CoV-2 infection often leads to the development of acute respiratory distress syndrome (ARDS), with profound pulmonary patho-histological changes post-mortem. It is not clear whether ARDS from SARS-CoV-2 is similar to that observed in influenza H1N1, another common viral cause of lung injury. Here, we analyze specific ARDS regions of interest utilizing a spatial transcriptomic platform on autopsy-derived lung tissue from patients with SARS-CoV-2 (n = 3), H1N1 (n = 3), and a dual infected individual (n = 1). Enhanced gene signatures in alveolar epithelium, vascular tissue, and lung macrophages identify not only increased regional coagulopathy but also increased extracellular remodeling, alternative macrophage activation, and squamous metaplasia of type II pneumocytes in SARS-CoV-2. Both the H1N1 and dual-infected transcriptome demonstrated an enhanced antiviral response compared to SARS-CoV-2. Our results uncover regional transcriptional changes related to tissue damage/remodeling, altered cellular phenotype, and vascular injury active in SARS-CoV-2 and present therapeutic targets for COVID-19-related ARDS.

VX-765 reduces neuroinflammation after spinal cord injury in mice

Inflammation is a major cause of neuronal injury after spinal cord injury. We hypothesized that inhibiting caspase-1 activation may reduce neuroinflammation after spinal cord injury, thus producing a protective effect in the injured spinal cord. A mouse model of T9 contusive spinal cord injury was established using an Infinite Horizon Impactor, and VX-765, a selective inhibitor of caspase-1, was administered for 7 successive days after spinal cord injury. The results showed that: (1) VX-765 inhibited spinal cord injury-induced caspase-1 activation and interleukin-1β and interleukin-18 secretion. (2) After spinal cord injury, an increase in M1 cells mainly came from local microglia rather than infiltrating macrophages. (3) Pro-inflammatory Th1Th17 cells were predominant in the Th subsets. VX-765 suppressed total macrophage infiltration, M1 macrophages/microglia, Th1 and Th1Th17 subset differentiation, and cytotoxic T cells activation; increased M2 microglia; and promoted Th2 and Treg differentiation. (4) VX-765 reduced the fibrotic area, promoted white matter myelination, alleviated motor neuron injury, and improved functional recovery. These findings suggest that VX-765 can reduce neuroinflammation and improve nerve function recovery after spinal cord injury by inhibiting caspase-1/interleukin-1β/interleukin-18. This may be a potential strategy for treating spinal cord injury. This study was approved by the Animal Care Ethics Committee of Bengbu Medical College (approval No. 2017-037) on February 23, 2017.

Scavenger Receptors as Biomarkers and Therapeutic Targets in Cardiovascular Disease

The process of atherosclerosis leads to the formation of plaques in the arterial wall, resulting in a decreased blood supply to tissues and organs and its sequelae: morbidity and mortality. A class of membrane-bound proteins termed scavenger receptors (SRs) are closely linked to the initiation and progression of atherosclerosis. Increasing interest in understanding SR structure and function has led to the idea that these proteins could provide new routes for cardiovascular disease diagnosis, management, and treatment. In this review, we consider the main classes of SRs that are implicated in arterial disease. We consider how our understanding of SR-mediated recognition of diverse ligands, including modified lipid particles, lipids, and carbohydrates, has enabled us to better target SR-linked functionality in disease. We also link clinical studies on vascular disease to our current understanding of SR biology and highlight potential areas that are relevant to cardiovascular disease management and therapy.

CRID3, a blocker of apoptosis associated speck like protein containing a card, ameliorates murine spinal cord injury by improving local immune microenvironment

Background

After spinal cord injury (SCI), destructive immune cell subsets are dominant in the local microenvironment, which are the important mechanism of injury. Studies have shown that inflammasomes play an important role in the inflammation following SCI, and apoptosis-associated speck-like protein containing a card (ASC) is the adaptor protein shared by inflammasomes. Therefore, we speculated that inhibiting ASC may improve the local microenvironment of injured spinal cord. Here, CRID3, a blocker of ASC oligomerization, was used to study its effect on the local microenvironment and the possible role in neuroprotection following SCI.

Methods

Murine SCI model was created using an Infinite Horizon impactor at T9 vertebral level with a force of 50 kdynes and CRID3 (50 mg/kg) was intraperitoneally injected following injury. ASC and its downstream molecules in inflammasome signaling pathway were measured by western blot. The immune cell subsets were detected by immunohistofluorescence (IHF) and flow cytometry (FCM). The spinal cord fibrosis area, neuron survival, myelin preservation, and functional recovery were assessed.

Results

Following SCI, CRID3 administration inhibited inflammasome-related ASC and caspase-1, IL-1β, and IL-18 activation, which consequently suppressed M1 microglia, Th1 and Th1Th17 differentiation, and increased M2 microglia and Th2 differentiation. Accordingly, the improved histology and behavior have also been found.

Conclusions

CRID3 may ameliorate murine SCI by inhibiting inflammasome activation, reducing proinflammatory factor production, restoring immune cell subset balance, and improving local immune microenvironment, and early administration may be a promising therapeutic strategy for SCI.

Interleukin 33 Expression Induced by Aryl Hydrocarbon Receptor in Macrophages

Polycyclic aromatic hydrocarbons (PAHs) contained in airborne particulate matter have been identified as a contributing factor for inflammation in the respiratory tract. Recently, interleukin-33 (IL-33) is strongly suggested to be associated with airway inflammation. Aryl hydrocarbon receptor (AhR) is a receptor for PAHs to regulate several metabolic enzymes, but the relationships between AhR and airway inflammation are still unclear. In this study, we examined the role of AhR in the expression of IL-33 in macrophages. THP-1 macrophages mainly expressed IL-33 variant 5, which in turn was strongly induced by the AhR agonists 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD) and kynurenine (KYN). AhR antagonist CH223191 suppressed the increase in IL-33 expression. Promoter analysis revealed that the IL-33 promoter has 2 dioxin response elements (DREs). AhR was recruited to both DREs after treatment with TCDD or KYN as assessed by gel shift and chromatin immunoprecipitation assays. A luciferase assay showed that one of the DREs was functional and involved in the expression of IL-33. Macrophages isolated from AhR-null mice expressed only low levels of IL-33 even in response to treatment with AhR ligands compared with wild-type cells. The treatment of THP-1 macrophages with diesel particulate matter and particle extracts increased the mRNA and protein expression of IL-33. Taken together, the results show that ligand-activated AhR mediates the induction of IL-33 in macrophages via a DRE located in the IL-33 promoter region. AhR-mediated IL-33 induction could be involved in the exacerbation and/or prolongation of airway inflammation elicited by toxic chemical substances.

2-Methoxyestradiol inhibits high fat diet-induced obesity in rats through modulation of adipose tissue macrophage infiltration and immunophenotype

Recently, experimental studies demonstrated that 2-methoxyestradiol (2ME2) ameliorates high fat diet (HFD)-induced obesity and restores insulin sensitivity. However, the mechanisms underlying these effects are unveiled yet. The current study was undertaken to test the hypothesis that 2ME2 exerts its effects by modulating adipose tissue macrophages (ATMs) accumulation, polarization and immunophenotypes. The experiment was carried out in males Wistar rats (n = 28) for 13 consecutive weeks. In HFD-fed group; body weight, glucose intolerance, serum insulin, HOMA-IR, lipid profile and adipose tissue (AT) weight were significantly higher compared to normal standard diet (NSD)- fed rats. However, treatment of HFD-fed rats with 2ME2 (200 μg/kg/day; i.p. from the beginning of the 9th week) resulted in significant enhancements in all these parameters as compared to HFD-fed rats. Treatment with 2ME2 was associated with a significant reduction in macrophage infiltration in the AT, shifting macrophage polarization towards M2 phenotype as indicated by significant decrease in the expression of pro-inflammatory M1 macrophages markers (IL-6, IL-1β, CD11c and iNOS) and concurrent significant increase in the M2 anti-inflammatory macrophage markers (Arginase 1 and IL-10). 2ME2 ameliorates HFD-induced obesity and glucose intolerance through inhibition of ATM infiltration in AT and shifting macrophage polarization from pro-inflammatory M1 to M2 anti-inflammatory phenotypes.

The role of astrocytes in oxidative stress of central nervous system: A mixed blessing

Central nervous system (CNS) maintains a high level of metabolism, which leads to the generation of large amounts of free radicals, and it is also one of the most vulnerable organs to oxidative stress. Emerging evidences have shown that, as the key homeostatic cells in CNS, astrocytes are deeply involved in multiple aspects of CNS function including oxidative stress regulation. Besides, the redox level in CNS can in turn affect astrocytes in morphology and function. The complex and multiple roles of astrocytes indicate that their correct performance is crucial for the normal functioning of the CNS, and its dysfunction may result in the occurrence and progression of various neurological disorders. To date, the influence of astrocytes in CNS oxidative stress is rarely reviewed. Therefore, in this review we sum up the roles of astrocytes in redox regulation and the corresponding mechanisms under both normal and different pathological conditions.

Diminished CD68+ Cancer-Associated Fibroblast Subset Induces Regulatory T-Cell (Treg) Infiltration and Predicts Poor Prognosis of Oral Squamous Cell Carcinoma Patients

Although cancer-associated fibroblasts (CAFs) are crucial stromal cells, characterizing their heterogeneity is far from complete. This study reports a novel subset of CAFs in oral squamous cell carcinoma (OSCC), which positively expressed CD68, the classic marker of macrophages. The spatial and temporal distribution of the CD68⁺ CAF subset of OSCC (n = 104) was determined by CD68/actin alpha 2, smooth muscle (ACTA2+; α-SMA) immunohistochemistry of serial sections. The CD68⁺ α-SMA⁺ CAF subset was elevated from dysplasia to OSCC. Moreover, although both the tumor center and invasive front harbor an abundant CD68⁺ CAF subset, patients with low-CD68⁺ CAFs in the tumor center showed more recurrence after operation and shorter survival time, indicating the different function of CD68⁺ CAFs in tumor initiation and progression. Functional analysis in the OSCC-CAF co-culture system found knockdown of CD68 did not change the phenotype of CAFs, tumor growth, or migration. Unexpectedly, low-CD68⁺ CAFs were associated with aberrant immune balance. A high proportion of tumor-supportive Tregs was found in patients with low-CD68⁺ CAFs. Mechanistically, knockdown of CD68 in CAFs contributed to the up-regulation of chemokine CCL17 and CCL22 of tumor cells to enhance Treg recruitment. Thus, up-regulated CD68⁺ fibroblasts participate in tumor initiation, but the low-CD68⁺ CAF subset in OSCC is conducive to regulatory T-cell (Treg) recruitment in the tumor microenvironment and contribute to poor prognosis of OSCC patients.

Expression and localization of absent in melanoma 2 in the injured spinal cord

In traumatic brain injury, absent in melanoma 2 (AIM2) has been demonstrated to be involved in pyroptotic neuronal cell death. Although the pathophysiological mechanism of spinal cord injury is similar to that of brain injury, the expression and cellular localization of AIM2 after spinal cord injury is still not very clear. In the present study, we used a rat model of T9 spinal cord contusive injury, produced using the weight drop method. The rats were randomly divided into 1-hour, 6-hour, 1-day, 3-day and 6-day (post-injury time points) groups. Sham-operated rats only received laminectomy at T9 without contusive injury. Western blot assay revealed that the expression levels of AIM2 were not significantly different among the 1-hour, 6-hour and 1-day groups. The expression levels of AIM2 were markedly higher in the 1-hour, 6-hour and 1-day groups compared with the sham, 3-day and 7-day groups. Double immunofluorescence staining demonstrated that AIM2 was expressed by NeuN⁺ (neurons), GFAP⁺ (astrocytes), CNPase⁺ (oligodendrocytes) and CD11b⁺ (microglia) cells in the sham-operated spinal cord. In rats with spinal cord injury, AIM2 was also found in CD45⁺ (leukocytes) and CD68⁺ (activated microglia/macrophages) cells in the spinal cord at all time points. These findings indicate that AIM2 is mainly expressed in neurons, astrocytes, microglia and oligodendrocytes in the normal spinal cord, and that after spinal cord injury, its expression increases because of the infiltration of leukocytes and the activation of astrocytes and microglia/macrophages.

A Purification Technique for Adipose-Derived Stromal Cell Cultures Leads to a More Regenerative Cell Population

It has been demonstrated that adipose-derived stromal cells (ASCs) are a regenerative cell population with potential uses for bone and cartilage regeneration. However, the biomarker expression and heterogeneity of the population has not been thoroughly characterized. By analyzing biomarker expression, we aimed to understand the composition of ASC populations extracted using a common extraction technique in comparison to ASC populations given an additional purification step. Human adipose tissue samples were collected, and ASCs were extracted from these samples using a common, published extraction technique (primary extraction). These cells were cultured and half were given an additional purification. The primarily-extracted and purified cell populations were analyzed for biomarkers that correspond to specific cell types. The addition of the purification technique reduced the number of cells expressing hematopoietic and endothelial biomarkers and did not cause the yield of mesenchymal stem cell biomarker-expressing cells to decrease. Biomarkers corresponding to erythrocytes and lymphocytes were lost during the primary extraction, and biomarkers corresponding to most granulocytes and progenitor cells were lost during the additional purification. Biomarkers identifying dendritic cells, monocytes/macrophages, neutrophils, vascular endothelial cells, smooth muscle cells, and pericytes were upregulated in purified cell populations while those identifying fibroblasts and adipocytes were downregulated. Pluripotency biomarkers were more highly expressed in purified cell populations. These results demonstrate that the most commonly utilized adipose tissue recovery and ASC extraction technique leads to a heterogeneous cell population in which further purification of this population, as described in this manuscript, isolates a cell subset that has more regenerative potential.

Regeneration in distantly related species: common strategies and pathways

While almost all animals are able to at least partially replace some lost parts, regeneration abilities vary considerably across species. Here we study gene expression patterns in distantly related species to investigate conserved regeneration strategies. To this end, we collect from the literature transcriptomic data obtained during the regeneration of three species (Hydra magnipapillata, Schmidtea mediterranea, and Apostichopus japonicus), and compare them with gene expression during regeneration in vertebrates and mammals. This allows us to identify a common set of differentially expressed genes and relevant shared pathways that are conserved across species during the early stage of the regeneration process. We also find a set of differentially expressed genes that in mammals are associated to the presence of macrophages and to the epithelial–mesenchymal transition. This suggests that features of the sophisticated wound healing strategy of mammals are already observable in earlier emerging metazoans.

All animals capable of regenerating a lost body part, from an organ or a limb to the whole organism, use a common set of genes. This is the striking discovery of a team of researchers from the Center for Complexity and Biosystems of the University of Milan, led by Caterina La Porta. They analyzed the genetic activity in regenerating tissues from widely different species—from hydra to mice. They found that some of the genes active at the beginning of the regeneration process are the same in very different species, including mammals which have lost this function during evolution, except for the restoration of the liver. The discovery of this shared genetic signature is of great importance to understand how regeneration evolved and could be useful for future regeneration therapies.

NADPH oxidases as drug targets and biomarkers in neurodegenerative diseases: What is the evidence?

Neurodegenerative disease are frequently characterized by microglia activation and/or leukocyte infiltration in the parenchyma of the central nervous system and at the molecular level by increased oxidative modifications of proteins, lipids and nucleic acids. NADPH oxidases (NOX) emerged as a novel promising class of pharmacological targets for the treatment of neurodegeneration due to their role in oxidant generation and presumably in regulating microglia activation. The unique function of NOX is the generation of superoxide anion (O₂^•-) and hydrogen peroxide (H₂O₂). However in the context of neuroinflammation, they present paradoxical features since O₂^•-/H₂O₂ generated by NOX and/or secondary reactive oxygen species (ROS) derived from O₂^•-/H₂O₂ can either lead to neuronal oxidative damage or resolution of inflammation. The role of NOX enzymes has been investigated in many models of neurodegenerative diseases by using either genetic or pharmacological approaches. In the present review we provide a critical assessment of recent findings related to the role of NOX in the CNS as well as how the field has advanced over the last 5 years. In particular, we focus on the data derived from the work of a consortium (Neurinox) funded by the European Commission's Programme 7 (FP7). We discuss the evidence gathered from animal models and human samples linking NOX expression/activity with neuroinflammation in neurodegenerative diseases, such as amyotrophic lateral sclerosis (ALS) and Creutzfeldt-Jakob disease as well as autoimmune demyelinating diseases like multiple sclerosis (MS) and chronic inflammatory demyelinating polyneuropathy (CIDP). We address the possibility to use measurement of the activity of the NOX2 isoform in blood samples as biomarker of disease severity and treatment efficacy in neurodegenerative disease. Finally we clarify key controversial aspects in the field of NOX, such as NOX cellular expression in the brain, measurement of NOX activity, impact of genetic deletion of NOX in animal models of neurodegeneration and specificity of NOX inhibitors.

Macrophage Area Content and Phenotype in Hepatic and Adipose Tissue in Patients with Obesity Undergoing Roux-en-Y Gastric Bypass

OBJECTIVE

To investigate hepatic and adipose tissue macrophage content in subjects with obesity and the role of adipose tissue macrophages in weight loss-induced improved insulin sensitivity (IS).

METHODS

A cross-sectional and a longitudinal study were combined to investigate the role of macrophages in subcutaneous (SAT) and visceral (VAT) adipose tissue and the liver in obesity-induced impaired IS and improvements with weight loss. Macrophage markers (CD68, CD163, and CD206) in SAT, VAT, and the liver from patients with obesity were investigated. The same macrophage markers were investigated in SAT from 18 patients with obesity before and ∼18 months after a diet- and Roux-en-Y gastric bypass-induced weight loss.

RESULTS

SAT macrophage markers did not decrease with weight loss, but macrophage concentration may have increased, concomitant with improved IS. Hepatic macrophage markers did not correlate to VAT mass or macrophage markers, but they were higher in patients with obesity compared with patients without obesity. Hepatic anti-inflammatory macrophage markers correlated positively with hepatic IS. VAT and SAT macrophage markers did not correlate.

CONCLUSIONS

The results indicate that decreased SAT macrophage content is not a primary driver for weight loss-induced IS improvements, but a better hepatic CD163 and CD206 macrophage profile may contribute to improved glycemic control. SAT macrophage markers were not predictive for VAT macrophage markers.

Peripheral Tumor Necrosis Factor-Alpha (TNF-α) Modulates Amyloid Pathology by Regulating Blood-Derived Immune Cells and Glial Response in the Brain of AD/TNF Transgenic Mice

Increasing evidence has suggested that systemic inflammation along with local brain inflammation can play a significant role in Alzheimer's disease (AD) pathogenesis. Identifying key molecules that regulate the crosstalk between the immune and the CNS can provide potential therapeutic targets. TNF-α is a proinflammatory cytokine implicated in the pathogenesis of systemic inflammatory and neurodegenerative diseases, such as rheumatoid arthritis (RA) and AD. Recent studies have reported that anti-TNF-α therapy or RA itself can modulate AD pathology, although the underlying mechanism is unclear. To investigate the role of peripheral TNF-α as a mediator of RA in the pathogenesis of AD, we generated double-transgenic 5XFAD/Tg197 AD/TNF mice that develop amyloid deposits and inflammatory arthritis induced by human TNF-α (huTNF-α) expression. We found that 5XFAD/Tg197 mice display decreased amyloid deposition, compromised neuronal integrity, and robust brain inflammation characterized by extensive gliosis and elevated blood-derived immune cell populations, including phagocytic macrophages and microglia. To evaluate the contribution of peripheral huTNF-α in the observed brain phenotype, we treated 5XFAD/Tg197 mice systemically with infliximab, an anti-huTNF-α antibody that does not penetrate the blood-brain barrier and prevents arthritis. Peripheral inhibition of huTNF-α increases amyloid deposition, rescues neuronal impairment, and suppresses gliosis and recruitment of blood-derived immune cells, without affecting brain huTNF-α levels. Our data report, for the first time, a distinctive role for peripheral TNF-α in the modulation of the amyloid phenotype in mice by regulating blood-derived and local brain inflammatory cell populations involved in β-amyloid clearance.SIGNIFICANCE STATEMENT Mounting evidence supports the active involvement of systemic inflammation, in addition to local brain inflammation, in Alzheimer's disease (AD) progression. TNF-α is a pluripotent cytokine that has been independently involved in the pathogenesis of systemic inflammatory rheumatoid arthritis (RA) and AD. Here we first demonstrate that manipulation of peripheral TNF-α in the context of arthritis modulates the amyloid phenotype by regulating immune cell trafficking in the mouse brain. Our study suggests that additionally to its local actions in the AD brain, TNF-α can also indirectly modulate amyloid pathology as a regulator of peripheral inflammation. Our findings may have significant implications in the treatment of RA patients with anti-TNF-α drugs and in the potential use of TNF-targeted therapies for AD.

CD68/macrosialin: not just a histochemical marker

CD68 is a heavily glycosylated glycoprotein that is highly expressed in macrophages and other mononuclear phagocytes. Traditionally, CD68 is exploited as a valuable cytochemical marker to immunostain monocyte/macrophages in the histochemical analysis of inflamed tissues, tumor tissues, and other immunohistopathological applications. CD68 alone or in combination with other cell markers of tumor-associated macrophages showed a good predictive value as a prognostic marker of survival in cancer patients. Lowression of CD68 was found in the lymphoid cells, non-hematopoietic cells (fibroblasts, endothelial cells, etc), and tumor cells. Cell-specific CD68 expression and differentiated expression levels are determined by the complex interplay between transcription factors, regulatory transcriptional elements, and epigenetic factors. Human CD68 and its mouse ortholog macrosialin belong to the family of LAMP proteins located in the lysosomal membrane and share many structural similarities such as the presence of the LAMP-like domain. Except for a second LAMP-like domain present in LAMPs, CD68/microsialin has a highly glycosylated mucin-like domain involved in ligand binding. CD68 has been shown to bind oxLDL, phosphatidylserine, apoptotic cells and serve as a receptor for malaria sporozoite in liver infection. CD68 is mainly located in the endosomal/lysosomal compartment but can rapidly shuttle to the cell surface. However, the role of CD68 as a scavenger receptor remains to be confirmed. It seems that CD68 is not involved in binding bacterial/viral pathogens, innate, inflammatory or humoral immune responses, although it may potentially be involved in antigen processing/presentation. CD68 could be functionally important in osteoclasts since its deletion leads to reduced bone resorption capacity. The role of CD68 in atherosclerosis is contradictory.

Intimal pericytes as the second line of immune defence in atherosclerosis

Inflammation plays an essential role in the development of atherosclerosis. The initiation and growth of atherosclerotic plaques is accompanied by recruitment of inflammatory and precursor cells from the bloodstream and their differentiation towards pro-inflammatory phenotypes. This process is orchestrated by the production of a number of pro-inflammatory cytokines and chemokines. Human arterial intima consists of structurally distinct leaflets, with a proteoglycan-rich layer lying immediately below the endothelial lining. Recent studies reveal the important role of stellate pericyte-like cells (intimal pericytes) populating the proteoglycan-rich layer in the development of atherosclerosis. During the pathologic process, intimal pericytes may participate in the recruitment of inflammatory cells by producing signalling molecules and play a role in the antigen presentation. Intimal pericytes are also involved in lipid accumulation and the formation of foam cells. This review focuses on the role of pericyte-like cells in the development of atherosclerotic lesions.

64Cu-DOTATATE PET/MRI for Detection of Activated Macrophages in Carotid Atherosclerotic Plaques: Studies in Patients Undergoing Endarterectomy

OBJECTIVE

A feature of vulnerable atherosclerotic plaques of the carotid artery is high activity and abundance of lesion macrophages. There is consensus that this is of importance for plaque vulnerability, which may lead to clinical events, such as stroke and transient ischemic attack. We used positron emission tomography (PET) and the novel PET ligand [(64)Cu] [1,4,7,10-tetraazacyclododecane-N,N',N″,N‴-tetraacetic acid]-d-Phe1,Tyr3-octreotate ((64)Cu-DOTATATE) to specifically target macrophages via the somatostatin receptor subtype-2 in vivo.

APPROACH AND RESULTS

Ten patients underwent simultaneous PET/MRI to measure (64)Cu-DOTATATE uptake in carotid artery plaques before carotid endarterectomy. (64)Cu-DOTATATE uptake was significantly higher in symptomatic plaque versus the contralateral carotid artery (P<0.001). Subsequently, a total of 62 plaque segments were assessed for gene expression of selected markers of plaque vulnerability using real-time quantitative polymerase chain reaction. These results were compared with in vivo (64)Cu-DOTATATE uptake calculated as the mean standardized uptake value. Univariate analysis of real-time quantitative polymerase chain reaction and PET showed that cluster of differentiation 163 (CD163) and CD68 gene expression correlated significantly but weakly with mean standardized uptake value in scans performed 85 minutes post injection (P<0.001 and P=0.015, respectively). Subsequent multivariate analysis showed that CD163 correlated independently with (64)Cu-DOTATATE uptake (P=0.031) whereas CD68 did not contribute significantly to the final model.

CONCLUSIONS

The novel PET tracer (64)Cu-DOTATATE accumulates in atherosclerotic plaques of the carotid artery. CD163 gene expression correlated independently with (64)Cu-DOTATATE uptake measured by real-time quantitative polymerase chain reaction in the final multivariate model, indicating that (64)Cu-DOTATATE PET is detecting alternatively activated macrophages. This association could potentially improve noninvasive identification and characterization of vulnerable plaques.

The complexity of cell composition of the intima of large arteries: focus on pericyte-like cells

Pericytes, which are also known as Rouget cells or perivascular cells, are considered to represent a likely distinct pool of vascular cells that are extremely branched and located mostly in the periphery of the vascular system. The family of pericytes is a heterogeneous cell population that includes pericytes and pericyte-like cells. Accumulated data indicate that networks of pericyte-like cells exist in normal non-atherosclerotic intima, and that pericyte-like cells can be involved in the development of atherosclerotic lesions from the very early stages of disease. The pathogenic role of arterial pericytes and pericyte-like cells also might be important in advanced and complicated atherosclerotic lesions via realizing mechanisms of vascular remodelling, ectopic ossification, intraplaque neovascularization, and probably thrombosis.

The Nax Channel

Na x, which is preferentially expressed in the glial cells of sensory circumventricular organs in the brain, is a sodium channel that is poorly homologous to voltage-gated sodium channels. We previously reported that Na x is a sodium concentration ([Na+])-sensitive, but not a voltage-sensitive channel that is critically involved in body-fluid homeostasis. Nax-knockout mice do not stop ingesting salt even when dehydrated and transiently develop hypernatremia. [Na+] in body fluids is strictly controlled at 135 to 145 mM in mammals. Although the set point must be within this range, Na x was shown to have a threshold value of ~150 mM for extracellular [Na+] ([Na+]o) for activation in vitro. Therefore, the [Na+]o dependency of Na x in vivo is presumably modified by an as yet unidentified mechanism. We recently demonstrated that the [Na+]o dependency of Na x in the subfornical organ was adjusted to the physiological range by endothelin-3. Pharmacological experiments revealed that endothelin receptor B signaling was involved in this modulation of Na x gating through protein kinase C and ERK1/2 activation. In addition, we identified a case of essential hypernatremia caused by autoimmunity to Na x. Occurrence of a ganglioneuroma composed of Schwann-like cells that robustly expressed Na x was likely to induce the autoimmune response in this patient. An intravenous injection of the immunoglobulin fraction of the patient’s serum, which contained anti-Na x antibodies, into mice reproduced the patient’s symptoms. This review provides an overview of the physiological functions of Na x by summarizing our recent studies.

Alveolar macrophages infected with Ames or Sterne strain of Bacillus anthracis elicit differential molecular expression patterns

Alveolar macrophages (AMs) phagocytose Bacillus anthracis following inhalation and induce the production of pro-inflammatory cytokines and chemokines to mediate the activation of innate immunity. Ames, the virulent strain of B. anthracis, contains two plasmids that encode the antiphagocytic poly-γ-d-glutamic acid capsule and the lethal toxin. The attenuated Sterne strain of B. anthracis, which lacks the plasmid encoding capsule, is widely adapted as a vaccine strain. Although differences in the outcome of infection with the two strains may have originated from the presence or absence of an anti-phagocytic capsule, the disease pathogenesis following infection will be manifested via the host responses, which is not well understood. To gain understanding of the host responses at cellular level, a microarray analysis was performed using primary rhesus macaque AMs infected with either Ames or Sterne spores. Notably, 528 human orthologs were identified to be differentially expressed in AMs infected with either strain of the B. anthracis. Meta-analyses revealed genes differentially expressed in response to B. anthracis infection were also induced upon infections with multiple pathogens such as Francisella Novicida or Staphylococcus aureus. This suggests the existence of a common molecular signature in response to pathogen infections. Importantly, the microarray and protein expression data for certain cytokines, chemokines and host factors provide further insights on how cellular processes such as innate immune sensing pathways, anti-apoptosis versus apoptosis may be differentially modulated in response to the virulent or vaccine strain of B. anthracis. The reported differences may account for the marked difference in pathogenicity between these two strains.

Inflammatory cytokines and chemokines, skeletal muscle and polycystic ovary syndrome: effects of pioglitazone and metformin treatment

OBJECTIVE

Chronic low-grade inflammation is a common feature of insulin resistant states, including obesity and type 2 diabetes. Less is known about inflammation in Polycystic Ovary Syndrome (PCOS). Thus we evaluated the impact of PCOS on circulating cytokine levels and the effects of anti-diabetic therapies on insulin action, cytokine and chemokine levels and inflammatory signaling in skeletal muscle.

METHODS

Twenty subjects with PCOS and 12 healthy normal cycling (NC) subjects of similar body mass index were studied. PCOS subjects received oral placebo or pioglitazone, 45 mg/d, for 6 months. All PCOS subjects then had metformin, 2 g/day, added to their treatment. Circulating levels of cytokines, chemokines, and adiponectin, skeletal muscle markers of inflammation and phosphorylation of signaling proteins, insulin action evaluated by the hyperinsulinemic/euglycemic clamp procedure and Homeostasis Model Assessment of Insulin Resistance were measured.

RESULTS

Circulating levels of a number of cytokines and chemokines were generally similar between PCOS and NC subjects. Levels in PCOS subjects were not altered by pioglitazone or metformin treatment, even though whole body insulin action and adiponectin levels increased with pioglitazone. In spite of the lack of change in levels of cytokines and chemokines, several markers of inflammation in skeletal muscle were improved with Pio treatment.

CONCLUSIONS

PCOS may represent a state of elevated sensitivity of inflammatory cells in skeletal muscle to cytokines and chemokines, a property that could be reversed by pioglitazone treatment together with improved insulin action.

Macrophage-related diseases of the gut: a pathologist's perspective

The resident macrophages of the gastrointestinal tract represent the largest population of macrophages in the human body and are usually located in the subepithelial lamina propria. This strategic location guarantees a first-line defense to the huge numbers of potentially harmful bacteria and antigenic stimuli that are present in the intestinal lumen. In non-inflamed mucosa, macrophages phagocytose and kill microbes in the absence of an inflammatory response. However, in the event of an epithelial breach and/or microbial invasion, new circulating monocytes and lymphocytes will be recruited to the damaged area of the gut, which will result in the secretion of proinflammatory mediators and engage a protective inflammatory response. Although macrophages are usually not conspicuous in normal mucosal samples of the gut, they can easily be detected when they accumulate exogenous particulate material or endogenous substances or when they become very numerous. These events will mostly occur in pathologic conditions, and this review presents an overview of the diseases which are either mediated by or affecting the resident macrophages of the gut.

Microglial scavenger receptors and their roles in the pathogenesis of Alzheimer's disease

Alzheimer's disease (AD) is increasing in prevalence with the aging population. Deposition of amyloid-β (Aβ) in the brain of AD patients is a hallmark of the disease and is associated with increased microglial numbers and activation state. The interaction of microglia with Aβ appears to play a dichotomous role in AD pathogenesis. On one hand, microglia can phagocytose and clear Aβ, but binding of microglia to Aβ also increases their ability to produce inflammatory cytokines, chemokines, and neurotoxic reactive oxygen species (ROS). Scavenger receptors, a group of evolutionally conserved proteins expressed on the surface of microglia act as receptors for Aβ. Of particular interest are SCARA-1 (scavenger receptor A-1), CD36, and RAGE (receptor for advanced glycation end products). SCARA-1 appears to be involved in the clearance of Aβ, while CD36 and RAGE are involved in activation of microglia by Aβ. In this review, we discuss the roles of various scavenger receptors in the interaction of microglia with Aβ and propose that these receptors play complementary, nonredundant functions in the development of AD pathology. We also discuss potential therapeutic applications for these receptors in AD.

Pathophysiology of perinatal asphyxia: can we predict and improve individual outcomes?

Perinatal asphyxia occurs still with great incidence whenever delivery is prolonged, despite improvements in perinatal care. After asphyxia, infants can suffer from short- to long-term neurological sequelae, their severity depend upon the extent of the insult, the metabolic imbalance during the re-oxygenation period and the developmental state of the affected regions. Significant progresses in understanding of perinatal asphyxia pathophysiology have achieved. However, predictive diagnostics and personalised therapeutic interventions are still under initial development. Now the emphasis is on early non-invasive diagnosis approach, as well as, in identifying new therapeutic targets to improve individual outcomes. In this review we discuss (i) specific biomarkers for early prediction of perinatal asphyxia outcome; (ii) short and long term sequelae; (iii) neurocircuitries involved; (iv) molecular pathways; (v) neuroinflammation systems; (vi) endogenous brain rescue systems, including activation of sentinel proteins and neurogenesis; and (vii) therapeutic targets for preventing or mitigating the effects produced by asphyxia.

TGF-β limits IL-33 production and promotes the resolution of colitis through regulation of macrophage function

Mϕs promote tissue injury or repair depending on their activation status and the local cytokine milieu. It remains unclear whether the immunosuppressive effects of transforming growth factor β (TGF-β) serve a nonredundant role in Mϕ function in vivo. We generated Mϕ-specific transgenic mice that express a truncated TGF-β receptor II under control of the CD68 promoter (CD68TGF-βDNRII) and subjected these mice to the dextran sodium sulfate (DSS) model of colitis. CD68TGF-βDNRII mice have an impaired ability to resolve colitic inflammation as demonstrated by increased lethality, granulocytic inflammation, and delayed goblet cell regeneration compared with transgene negative littermates. CD68TGF-βDNRII mice produce significantly less IL-10, but have increased levels of IgE and numbers of IL-33+ Mϕs than controls. These data are consistent with associations between ulcerative colitis and increased IL-33 production in humans and suggest that TGF-β may promote the suppression of intestinal inflammation, at least in part, through direct effects on Mϕ function.

TGF-β limits IL-33 production and promotes the resolution of colitis through regulation of macrophage function

Mϕs promote tissue injury or repair depending on their activation status and the local cytokine milieu. It remains unclear whether the immunosuppressive effects of transforming growth factor β (TGF-β) serve a nonredundant role in Mϕ function in vivo. We generated Mϕ-specific transgenic mice that express a truncated TGF-β receptor II under control of the CD68 promoter (CD68TGF-βDNRII) and subjected these mice to the dextran sodium sulfate (DSS) model of colitis. CD68TGF-βDNRII mice have an impaired ability to resolve colitic inflammation as demonstrated by increased lethality, granulocytic inflammation, and delayed goblet cell regeneration compared with transgene negative littermates. CD68TGF-βDNRII mice produce significantly less IL-10, but have increased levels of IgE and numbers of IL-33+ Mϕs than controls. These data are consistent with associations between ulcerative colitis and increased IL-33 production in humans and suggest that TGF-β may promote the suppression of intestinal inflammation, at least in part, through direct effects on Mϕ function.

Macrophages in renal development, injury, and repair

Macrophages have long been regarded as classic mediators of innate immunity because of their production of proinflammatory cytokines and their ability to induce apoptotic cell death. As a result of such activities and the detrimental long-term effect of kidney inflammation, macrophages principally have been regarded as mediators of glomerular damage, tubular cell death, and the downstream fibrotic events leading to chronic kidney disease. Although this has been the accepted consequence of macrophage infiltration in kidney disease, macrophages also play a critical role in normal organ development, cell turnover, and recovery from injury in many organs, including the kidney. There is also a growing awareness that there is considerable heterogeneity of phenotype and function within the macrophage population and that a greater understanding of these different states of activation may result in the development of therapies specifically designed to capitalize on this variation in phenotype and cellular responses. In this review, we discuss the current understanding of induction and consequences of classic versus alternative macrophage activation and highlight what additional therapeutic options this may provide for the management of both acute and chronic kidney disease as well as renal cancer.

Biodegradable xylitol-based elastomers: in vivo behavior and biocompatibility

Biodegradable elastomers based on polycondensation reactions of xylitol with sebacic acid, referred to as poly(xylitol sebacate) (PXS) elastomers have recently been developed. We describe the in vivo behavior of PXS elastomers. Four PXS elastomers were synthesized, characterized, and compared with poly(L-lactic-co-glycolic acid) (PLGA). PXS elastomers displayed a high level of structural integrity and form stability during degradation. The in vivo half-life ranged from approximately 3 to 52 weeks. PXS elastomers exhibited increased biocompatibility compared with PLGA implants.

Autoimmunity to the sodium-level sensor in the brain causes essential hypernatremia

Na(x) is the sodium-level sensor of body fluids in the brain involved in sodium homeostasis. Na(x)-knockout mice do not stop ingesting salt even when dehydrated. Here we report a case with clinical features of essential hypernatremia without demonstrable hypothalamic structural lesions, who was diagnosed as a paraneoplastic neurologic disorder. The patient had autoantibodies directed against Na(x), along with a ganglioneuroma composed of Schwann-like cells robustly expressing Na(x). The removal of the tumor did not reduce the autoantibody levels or relieve the symptoms. Intravenous injection of the immunoglobulin fraction of the patient's serum into mice induced abnormalities in water/salt intake and diuresis, which led to hypernatremia. In the brains of these mice, cell death was observed along with focal deposits of complement C3 and inflammatory infiltrates in circumventricular organs where Na(x) is specifically expressed. Our findings thus provide new insights into the pathogenesis of hypernatremia relevant to the sodium-level-sensing mechanism in humans.

Innate immunity and neuroinflammation in the CNS: the role of microglia in Toll-like receptor-mediated neuronal injury

Microglia are key players of the immune response in the central nervous system (CNS) and, being the resident innate immune cells, they are responsible for the early control of infections and for the recruitment of cells of the adaptive immune system required for pathogen clearance. The innate and adaptive immune responses triggered by microglia include the release of proinflammatory mediators. Although an efficient immune response is required for the defense against invading pathogens, an inflammatory response in the CNS may also lead to tissue injury and neurodegeneration. Engagement of Toll-like receptors (TLRs), a major family of pattern recognition receptors that mediate innate immunity but also link with the adaptive immune response, provides an important mechanism by which microglia are able to sense both pathogen- and host-derived ligands within the CNS. Although there is an increasing body of evidence that TLR signaling mediates beneficial effects in the CNS, it has become clear that TLR-induced activation of microglia and the release of proinflammatory molecules are responsible for neurotoxic processes in the course of various CNS diseases. Thus, the functional outcome of TLR-induced activation of microglia in the CNS depends on a subtle balance between protective and harmful effects. This review focuses on the neurodegenerative effects of TLR signaling in the CNS.

The effect of CpG motifs on gene expression and clearance kinetics of aerosol administered polyethylenimine (PEI)-plasmid DNA complexes in the lung

Presence of CpG motifs within pDNA is widely reported to influence transgene expression as well as inflammatory response to nonviral gene vector complexes. Here, we analyzed gene expression kinetics and lung clearance after aerosol delivery of polyethylenimine (PEI) complexes with two different plasmid vectors: a first generation plasmid, pCMVLuc, and a plasmid with depleted CpG motifs, pCpG-free-Luc. After aerosol delivery, equal nanogram amounts of PEI-pDNA complexes were deposited in murine lungs. Luciferase expression observed at day one post administration of PEI-pCpG-free-Luc complexes was 60-fold higher than for PEI-pCMVLuc complexes and decreased 16-fold at day 7 post application. In contrast, luciferase expression from PEI-pCMVLuc particles remained at levels comparable to day 1 post application. In agreement with these observations, PEI-pCpG-free-Luc complexes were cleared from the lungs at rates 6-fold faster than those observed for PEI-pCMVLuc particles. A more detailed analysis of pDNA distribution within bronchoalveolar lavage fluid (BALF), BALF cells and lung tissue showed 660-fold higher amounts of pCpG-free-Luc in BALF cells compared to pCMVLuc, whereas the amount of pCpG-free-Luc in lung tissue was 15-fold lower compared to pCMVLuc 1h after administration. Our results demonstrate that complexes of PEI with CpG-motif-free DNA are taken up more extensively by BALF cells, while the clearance of pCMVLuc from the lung tissue is significantly slower than for the CpG-free plasmid. Administration of PEI-pCpG-free-Luc caused transient decrease in number of resident lung cells, while their activation was more pronounced with PEI-pCMVLuc particles. Our results demonstrate that the level of transgene expression is increased with CpG-motif-free pDNA but the longevity of expression correlates with pDNA clearance pattern depending on the presence of CpG motifs within the plasmid.

The relationship of visfatin/pre-B-cell colony-enhancing factor/nicotinamide phosphoribosyltransferase in adipose tissue with inflammation, insulin resistance, and plasma lipids

Visfatin/pre-B-cell colony-enhancing factor (PBEF)/nicotinamide phosphoribosyltransferase (Nampt) has been proposed as an insulin-mimicking adipocytokine predominantly secreted from visceral adipose tissue (VAT) and correlated with obesity. However, recent evidence challenged this proposal and instead suggested visfatin/PBEF/Nampt as a proinflammatory cytokine. The study aimed to examine whether visfatin/PBEF/Nampt was predominantly expressed in VAT and was correlated with obesity. The relationship of visfatin/PBEF/Nampt gene expression in adipose tissues with proinflammatory gene expression and metabolic phenotypes was also examined. The relative messenger RNA (mRNA) levels of visfatin/PBEF/Nampt, macrophage-specific marker CD68, and proinflammatory genes were measured in paired abdominal VAT and subcutaneous adipose tissues (SAT) and from 53 nondiabetic adults using quantitative real-time polymerase chain reaction. Fasting glucose, insulin, triglyceride, cholesterol, and uric acid levels were measured; and systemic insulin sensitivity was quantified with modified insulin suppression tests. There was no difference in visfatin/PBEF/Nampt mRNA levels between VAT and SAT, and neither was associated with measures of obesity. Visfatin/PBEF/Nampt mRNA levels were strongly correlated with proinflammatory gene expression including CD68 and tumor necrosis factor-alpha gene in both VAT and SAT. The VAT and SAT visfatin/PBEF/Nampt mRNA expressions were positively correlated with steady-state plasma glucose concentrations measured with modified insulin suppression tests, a direct measurement of systemic insulin resistance (r = 0.42, P = .03 and r = 0.44, P = .03, respectively). The VAT visfatin/PBEF/Nampt mRNA expression was also positively correlated with fasting triglyceride (r = 0.42, P = .002) and total cholesterol levels (r = 0.37, P = .009). Visfatin/PBEF/Nampt is not predominantly secreted from VAT and is not correlated with obesity. Our findings suggest that visfatin/PBEF/Nampt is a proinflammatory marker of adipose tissue associated with systemic insulin resistance and hyperlipidemia.

Fibroblast growth factor expression during skeletal fracture healing in mice

Fibroblast growth factors (FGFs) are important signaling molecules that regulate many stages of endochondral bone development. During the healing of a skeletal fracture, several features of endochondral bone development are reactivated. To better understand the role of FGFs in skeletal fracture healing, we quantitatively evaluated the temporal expression patterns of Fgfs, Fgf receptors (Fgfrs), and molecular markers of bone development over a 14-day period following long bone fracture in a mouse model. These studies identify distinct groups of FGFs that are differentially expressed and suggest active stage-specific roles for FGF signaling during the fracture repair process.

Dysfunctional microvasculature as a consequence of shb gene inactivation causes impaired tumor growth

Shb (Src homology 2 protein B) is an adapter protein downstream of the vascular endothelial growth factor receptor receptor-2 (VEGFR-2). Previous experiments have suggested a role for Shb in endothelial cell function. Recently, the Shb gene was inactivated and Shb null mice were obtained on a mixed genetic background, but not on C57Bl6 mice. The present study was performed to address endothelial function in the Shb knockout mouse and its relevance for tumor angiogenesis. Tumor growth was retarded in Shb mutant mice, and this correlated with decreased angiogenesis both in tumors and in Matrigel plugs. Shb null mice display an abnormal endothelial ultrastructure in liver sinusoids and heart capillaries with cytoplasmic extensions projecting toward the lumen. Shb null heart VE-cadherin staining was less distinct than that of control heart, exhibiting in the former case a wavy and punctuate pattern. Experiments on isolated endothelial cells suggest that these changes could partly reflect cytoskeletal abnormalities. Vascular permeability was increased in Shb null mice in heart, kidney, and skin, whereas VEGF-stimulated vascular permeability was reduced in Shb null mice. It is concluded that Shb plays an important role in maintaining a functional vasculature in adult mice, and that interference with Shb signaling may provide novel means to regulate tumor angiogenesis.

Breast cancer expression of CD163, a macrophage scavenger receptor, is related to early distant recurrence and reduced patient survival

Cells of the monocyte/macrophage lineage are important for tumour cell migration, invasion and metastasis. Fusion between macrophages and cancer cells in animal models in vitro and in vivo causes hybrids with increased metastatic potential. Primary breast cancer cells were characterized for macrophage antigens to test if phenotypic resemblance to macrophages is related to early distant recurrence. Immunostaining for CD163, MAC387 and CD68 was performed in a breast cancer tissue micro array from 127 patients consequently followed up for a median of 13 years. Tumour-associated macrophages expressed all 3 antigens. The breast cancers expressed CD163 to 48%, MAC387 to 14% while CD68 was not expressed. TGF-beta staining intensity was positively related to both CD163 and MAC387 expression. Expression of CD163 in the cancer cells was compared to their DNA ploidy, Nottingham Histological Grade, TNM-stage, node state, presence of estrogen receptors and occurrence of distant metastases and survival. Cancers of a more advanced histological grade expressed CD163 to a higher extent. Cells expressing MAC387 were more common in cancers with a high proportion of CD163 positive cells. Multivariate analysis showed that expression of the macrophage antigen CD163 in breast cancer cells has a prognostic impact on the occurrence of distant metastases and reduced patient survival time.

Macrophage fusion: molecular mechanisms

Macrophages are the most versatile, plastic, and mobile cells in the animal kingdom. They are present in all tissues and might even define a true " body-wide" network that maintains health and ensures the repair of tissues and organs. In specific and rare instances, macrophages fuse to form multinucleate osteoclasts and giant cells in bone and in chronic inflammatory reactions, respectively. While macrophages lose most of their plasticity and mobility after they become multinucleate, at the same time they acquire the capacity to resorb calcified tissues, such as bone, and foreign bodies, such as pathogens and implants, and they mediate the replacement of the resorbed tissue by new tissue. There is evidence to suggest that macrophages might also fuse with somatic cells to repair tissues and with tumor cells to trigger the metastatic process. The molecular machinery of macrophage fusion remains poorly characterized, but it is likely to be shared by all fusing macrophages.

Gene signatures reflect the marked heterogeneity of tissue-resident macrophages

Tissue-resident macrophages play an important role in defense against pathogens and perform key functions in organ homeostasis, innate and adaptive immunity. Tissue macrophages originate from blood monocytes that infiltrate virtually every organ in the body. Macrophages in different tissues share many characteristics, including their ability to migrate, phagocytose particles, metabolize lipids and present antigens. Morphologically they are quite heterogeneous, and some distinct functions have been reported. The gene expression profile of macrophages is reflective of both their shared and distinct biological functions. Here, we show that macrophages from murine spleen, liver and peritoneum display dramatically different expression profiles. Clusters of genes were found to represent unique biological functions related to adhesion, antigen presentation, phagocytosis, lipid metabolism and signal transduction. Some gene families, such as integrins, are differentially expressed among the macrophages resident in different tissues, suggesting that the tissue of residence influences their biological function.

Inflammation and IGF-I activate the Akt pathway in breast cancer

Akt signaling may promote breast cancer progression and poor disease outcome. We hypothesized that serum insulin-like growth factor I (IGF-I) and a proinflammatory tumor environment induce phosphorylation of Akt and downstream targets of Akt in breast cancer. We studied the relationship between Akt pathway activation, IGF-I and markers of inflammation, e.g., nitric oxide synthase-2 (NOS2), cyclooxygenase-2 (COX2) and tumor phagocyte density, in 248 breast tumors. We also examined the association of Akt phosphorylation with breast cancer survival. We observed that phosphorylation of Akt, BAD and caspase-9 correlated strongly with the expression of the 2 proinflammatory enzymes, NOS2 and COX2, in breast tumors (p < 0.001; Spearman rank correlation). Both NOS2 and COX2 expression were independently associated with Akt phosphorylation in the multivariate analysis. Serum IGF-I concentrations and the IGF-I/IGFBP3 ratio correlated with Akt phosphorylation at Thr308 and Ser473 in breast tumors (p <or= 0.05; Spearman rank correlation). The association with Akt phosphorylation at Thr308 remained statistically significant in the multivariate analysis. Akt pathway activation was not associated with overall survival in the unstratified analysis, but we observed a statistical interaction between Akt phosphorylation and tumor phagocyte density on breast cancer survival (p(interaction) < 0.05). We further corroborated our findings in cell culture models by demonstrating that ANA-1 macrophages, nitric oxide and prostaglandin E(2) induce Akt phosphorylation in human breast cancer cells. In summary, a proinflammatory environment was found to activate the Akt pathway in breast cancer, and may modify the association between the Akt phosphorylation status and breast cancer survival.