Carcinoembryonic antigen-related cell adhesion molecule 1 controls IL-2-dependent regulatory T-cell induction in immune-mediated hepatitis in mice.

A dysbalance between effector T cells (Tconv) and regulatory T cells (Tregs) and impaired Treg function can cause autoimmune liver disease. Therefore, it is important to identify molecular mechanisms that control Treg homeostasis. Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1; CD66a) is an immune coreceptor with dichotomous roles in T-cell regulation: its short isoform (CEACAM1S) can activate T cells and induce Tregs, whereas its long isoform (CEACAM1L), containing two intracellular immune receptor tyrosine-based inhibitory motifs, can inhibit activated T-cell function. In the liver, CEACAM1 has antifibrotic effects in models of nonalcoholic steatohepatitis. However, its role in immune-mediated hepatitis is unknown. In the mouse model of concanavalin A-induced CD4+ T-cell-dependent liver injury, liver damage was aggravated and persisted in Ceacam1-/- mice. Concomitantly, we observed hyperexpansion of Tconv, but reduction of interleukin (IL)-2 production and hepatic forkhead box protein P3+ (Foxp3+ )CD4+ Treg numbers. CEACAM1-/- CD4+ T cells showed impaired IL-2-mediated signal transducer and activator of transcription 5 (STAT5) phosphorylation, which correlated with a failure of naïve CEACAM1-/- CD4+ T cells to convert into Tregs in vitro. Furthermore, CEACAM1-/- Tregs expressed reduced levels of Foxp3, CD25, and B-cell lymphoma 2. Adoptive transfer experiments demonstrated that hepatic Treg expansion and suppressive activity required CEACAM1 expression on both CD4+ T cells and Tregs. We identified predominant CEACAM1S expression on hepatic CD4+ T cells and Tregs from mice with acute liver injury and expression of both isoforms in liver-derived CD4+ T-cell clones from patients with liver injury. CONCLUSION: Our data suggest that CEACAM1S expression in CD4+ T cells augments IL-2 production and STAT5 phosphorylation leading to enhanced Treg induction and stability, which, ultimately, confers protection from T-cell-mediated liver injury. (Hepatology 2018;68:200-214).

Endothelial barrier function is differentially regulated by CEACAM1-mediated signaling.

Carcinoembryonic antigen-related cell adhesion molecule-1 (CEACAM1) is known to be crucial to vasculogenesis and angiogenesis. Recently, CEACAM1 deficiency was shown to result in the formation of aortic plaque-like lesions, indicating a role for CEACAM1 in adult vessels as well. The underlying mechanisms remained largely elusive. Therefore, we aimed to elucidate the role of CEACAM1 in endothelial homeostasis. Here, we show that CEACAM1 deficiency causes subcellular eNOS redistribution in endothelial cells ( i.e., by eNOS depalmitoylation) and alters endothelial glycocalyx that confers antiadhesive properties to the endothelium ( i.e., by repression of glycocalyx-degrading enzymes). Accordingly, our analysis revealed an increased leukocyte-endothelial interaction in CEACAM1-deficient endothelium. In addition, CEACAM1 age dependently modulated basal and TNF-α-mediated endothelial barrier (EB) leakiness. In younger mice, CEACAM1 was protective for EB, whereas in aged mice it promoted EB leakiness. EB function depends on interendothelial adherence junctions formed by ß-catenin/vascular endothelial-cadherin complexes. We show here that CEACAM1 influenced basal and TNF-α-mediated phosphorylation of ß-catenin and caveolin-1, which are essential players in EB modulation. Both increased adhesiveness to leukocytes and EB modulation due to CEACAM1 deficiency may facilitate inflammatory cell transmigration into the vascular wall and subsequent plaque formation. Collectively, these results identify a crucial role for CEACAM1 in endothelial homeostasis of adult blood vessels.-Ghavampour, S., Kleefeldt, F., Bömmel, H., Volland, J., Paus, A., Horst, A., Pfeiffer, V., Hübner, S., Wagner, N., Rueckschloss, U., Ergün, S. Endothelial barrier function is differentially regulated by CEACAM1-mediated signaling.

A Proinflammatory Role of Type 2 Innate Lymphoid Cells in Murine Immune-Mediated Hepatitis.

Type 2 innate lymphoid cells (ILC2) mediate inflammatory immune responses in the context of diseases triggered by the alarmin IL-33. In recent years, IL-33 has been implicated in the pathogenesis of immune-mediated liver diseases. However, the immunoregulatory function of ILC2s in the inflamed liver remains elusive. Using the murine model of Con A-induced immune-mediated hepatitis, we showed that selective expansion of ILC2s in the liver was associated with highly elevated hepatic IL-33 expression, severe liver inflammation, and infiltration of eosinophils. CD4+ T cell-mediated tissue damage and subsequent IL-33 release were responsible for the activation of hepatic ILC2s that produced the type 2 cytokines IL-5 and IL-13 during liver inflammation. Interestingly, ILC2 depletion correlated with less severe hepatitis and reduced accumulation of eosinophils in the liver, whereas adoptive transfer of hepatic ILC2s aggravated liver inflammation and tissue damage. We further showed that, despite expansion of hepatic ILC2s, 3-d IL-33 treatment before Con A challenge potently suppressed development of immune-mediated hepatitis. We found that IL-33 not only activated hepatic ILC2s but also expanded CD4+ Foxp3+ regulatory T cells (Treg) expressing the IL-33 receptor ST2 in the liver. This Treg subset also accumulated in the liver during resolution of immune-mediated hepatitis. In summary, hepatic ILC2s are poised to respond to the release of IL-33 upon liver tissue damage through expression of type 2 cytokines thereby participating in the pathogenesis of immune-mediated hepatitis. Inflammatory activity of ILC2s might be regulated by IL-33-elicited ST2+ Tregs that also arise in immune-mediated hepatitis.

CEACAM1 in Liver Injury, Metabolic and Immune Regulation.

Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) is a transmembrane glycoprotein that is expressed on epithelial, endothelial and immune cells. CEACAM1 is a differentiation antigen involved in the maintenance of epithelial polarity that is induced during hepatocyte differentiation and liver regeneration. CEACAM1 regulates insulin sensitivity by promoting hepatic insulin clearance, and controls liver tolerance and mucosal immunity. Obese insulin-resistant humans with non-alcoholic fatty liver disease manifest loss of hepatic CEACAM1. In mice, deletion or functional inactivation of CEACAM1 impairs insulin clearance and compromises metabolic homeostasis which initiates the development of obesity and hepatic steatosis and fibrosis with other features of non-alcoholic steatohepatitis, and adipogenesis in white adipose depot. This is followed by inflammation and endothelial and cardiovascular dysfunctions. In obstructive and inflammatory liver diseases, soluble CEACAM1 is shed into human bile where it can serve as an indicator of liver disease. On immune cells, CEACAM1 acts as an immune checkpoint regulator, and deletion of Ceacam1 gene in mice causes exacerbation of inflammation and hyperactivation of myeloid cells and lymphocytes. Hence, hepatic CEACAM1 resides at the central hub of immune and metabolic homeostasis in both humans and mice. This review focuses on the regulatory role of CEACAM1 in liver and biliary tract architecture in health and disease, and on its metabolic role and function as an immune checkpoint regulator of hepatic inflammation.

Sharpin Controls Osteogenic Differentiation of Mesenchymal Bone Marrow Cells.

The cytosolic protein Sharpin is a component of the linear ubiquitin chain assembly complex, which regulates NF-κB signaling in response to specific ligands, such as TNF-α. Its inactivating mutation in chronic proliferative dermatitis mutation (Cpdm) mice causes multiorgan inflammation, yet this phenotype is not transferable into wild-type mice by hematopoietic stem cell transfer. Recent evidence demonstrated that Cpdm mice additionally display low bone mass, and that this osteopenia is corrected by Tnf deletion. Because the cellular mechanism underlying this pathology, however, was still undefined, we performed a thorough skeletal phenotyping of Cpdm mice on the basis of nondecalcified histology and cellular and dynamic histomorphometry. We show that the trabecular and cortical osteopenia in Cpdm mice is solely explained by impaired bone formation, whereas osteoclastogenesis is unaffected. Consistently, Cpdm primary calvarial cells display reduced osteogenic capacity ex vivo, and the same was observed with CD11b(-) bone marrow cells. Unexpectedly, short-term treatment of these cultures with TNF-α did not reveal an impaired molecular response in the absence of Sharpin. Instead, genome-wide and gene-specific expression analyses revealed that Cpdm mesenchymal cells display increased responsiveness toward TNF-α-induced expression of specific cytokines, such as CXCL5, IL-1ß, and IL-6. Therefore, our data not only demonstrate that the skeletal defects of Cpdm mice are specifically caused by impaired differentiation of osteoprogenitor cells, they also suggest that increased cytokine expression in mesenchymal bone marrow cells contributes to the inflammatory phenotype of Cpdm mice.

CEA a thrombus CAM: CEACAM2, a twin of CEACAM1?

In this issue of Blood, Alshahrani et al demonstrate that carcinoembryonic antigen-related cell adhesion molecule 2 (CEACAM2) is expressed on platelets and negatively regulates the collagen receptor glycoprotein (GP)VI-FcRγ chain and C-type lectin-like receptor 2 (CLEC-2)-mediated platelet activation.

Microdomain Formation Controls Spatiotemporal Dynamics of Cell-Surface Glycoproteins.

The effect of galectin-mediated microdomain formation on the spatiotemporal dynamics of glycosylated membrane proteins in human microvascular endothelial cells (HMEC-1) was studied qualitatively and quantitatively by high-resolution fluorescence microscopy and artificially mimicked by metabolic glycoprotein engineering. Two types of membrane proteins, sialic acid-bearing proteins (SABPs) and mucin-type proteins (MTPs), were investigated. For visualization they were metabolically labeled with azido sugars and then coupled to a cyclooctyne-conjugated fluorescent dye by click chemistry. Both spatial (diffusion) and temporal (residence time) dynamics of SABPs and MTPs on the membrane were investigated after treatment with exogenous galectin-1 or -3. Strong effects of galectin-mediated lattice formation were observed for MTPs (decreased spatial mobility), but not for SABPs. Lattice formation also strongly decreased the turnover of MTPs (increased residence time on the cell membrane). The effects of galectin-mediated crosslinking was accurately mimicked by streptavidin-mediated crosslinking of biotin-tagged glycoproteins and verified by single-molecule tracking. This technique allows the induction of crosslinking of membrane proteins under precisely controlled conditions, thereby influencing membrane residence time and the spatial dynamics of glycans on the cell membrane in a controlled way.

Carcinoembryonic antigen-related cell adhesion molecule 1 inhibits MMP-9-mediated blood-brain-barrier breakdown in a mouse model for ischemic stroke.

RATIONALE: Blood-brain-barrier (BBB) breakdown and cerebral edema result from postischemic inflammation and contribute to mortality and morbidity after ischemic stroke. A functional role for the carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) in the regulation of reperfusion injury has not yet been demonstrated. OBJECTIVE: We sought to identify and characterize the relevance of CEACAM1-expressing inflammatory cells in BBB breakdown and outcome after ischemic stroke in Ceacam1(-/-) and wild-type mice. METHODS AND RESULTS: Focal ischemia was induced by temporary occlusion of the middle cerebral artery with a microfilament. Using MRI and Evans blue permeability assays, we observed increased stroke volumes, BBB breakdown and edema formation, reduction of cerebral perfusion, and brain atrophy in Ceacam1(-/-) mice. This translated into poor performance in neurological scoring and high poststroke-associated mortality. Elevated neutrophil influx, hyperproduction, and release of neutrophil-related matrix metalloproteinase-9 in Ceacam1(-/-) mice were confirmed by immune fluorescence, flow cytometry, zymography, and stimulation of neutrophils. Importantly, neutralization of matrix metalloproteinase-9 activity in Ceacam1(-/-) mice was sufficient to alleviate stroke sizes and improve survival to the level of CEACAM1-competent animals. Immune histochemistry of murine and human poststroke autoptic brains congruently identified abundance of CEACAM1(+)matrix metalloproteinase-9(+) neutrophils in the ischemic hemispheres. CONCLUSIONS: CEACAM1 controls matrix metalloproteinase-9 secretion by neutrophils in postischemic inflammation at the BBB after stroke. We propose CEACAM1 as an important inhibitory regulator of neutrophil-mediated tissue damage and BBB breakdown in focal cerebral ischemia.

Peripheral oxidative stress blood markers in patients with chronic back or neck pain treated with high-velocity, low-amplitude manipulation.

OBJECTIVE: The purpose of this study was to investigate oxidative-stress parameters in individuals with chronic neck or back pain after 5 weeks of treatment with high-velocity, low-amplitude (HVLA) spinal manipulation. METHODS: Twenty-three individuals aged 38.2 ± 11.7 years with nonspecific chronic neck or back pain verified by the Brazilian Portuguese version of the Chronic Pain Grade, with a sedentary lifestyle, no comorbidities, and not in adjuvant therapy, underwent treatment with HVLA chiropractic manipulation twice weekly for 5 weeks. Therapeutic procedures were carried out by an experienced chiropractor. Blood samples were assessed before and after treatment to determine the activities of the antioxidant enzymes superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx), and the levels of nitric oxide metabolites and lipid hydroperoxides. These blood markers were analyzed by paired Student t test. Differences were considered statistically significant, when P was <.05. RESULTS: There was no change in catalase but an increase in SOD (0.35 ± 0.03 U SOD per milligram of protein vs 0.44 ± 0.04 U SOD per milligram of protein; P < .05) and GPx (7.91 ± 0.61 nmol/min per milligram of protein vs 14.07 ± 1.07 nmol/min per milligram of protein; P < .001) activities after the treatment. The nitric oxide metabolites and the lipid hydroperoxides did not change after treatment. CONCLUSION: High-velocity, low-amplitude spinal manipulation twice weekly for 5 weeks increases the SOD and GPx activities. Previous studies have shown a relationship between pain and oxidative and nitrosative parameters; thus, it is possible that changes in these enzymes might be related to the analgesic effect of HVLA spinal manipulation.

Ultrafast extraction of proteins from tissues using desorption by impulsive vibrational excitation.

A picosecond IR laser (PIRL) can be used to blast proteins out of tissues through desorption by impulsive excitation (DIVE) of intramolecular vibrational states of water molecules in the cell in less than a millisecond. With PIRL-DIVE proteins covering a range of a few kDa up to several MDa are extracted in high quantities compared to conventional approaches. The chemical composition of extracted proteins remains unaltered and even enzymatic activities are maintained.

Infrared spectroscopy combined with chemometrics in transflectance mode: An alternative approach in the photodiagnosis of COVID-19 using saliva.

The Coronavirus Disease 2019 (COVID-19) pandemic, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has required the search for sensitive, rapid, specific, and lower-cost diagnostic methods to meet the high demand. The gold standard method of laboratory diagnosis is real-time reverse transcription polymerase chain reaction (RT-PCR). However, this method is costly and results can take time. In the literature, several studies have already described the potential of Fourier transform infrared spectroscopy (FTIR) as a tool in the biomedical field, including the diagnosis of viral infections, while being fast and inexpensive. In view of this, the objective of this study was to develop an FTIR model for the diagnosis of COVID-19. For this analysis, all private clients who had performed a face-to-face collection at the Univates Clinical Analysis Laboratory (LAC Univates) within a period of six months were invited to participate. Data from clients who agreed to participate in the study were collected, as well as nasopharyngeal secretions and a saliva sample. For the development of models, the RT-PCR result of nasopharyngeal secretions was used as a reference method. Absorptions with high discrimination (p < 0.001) between GI (28 patients, RT-PCR test positive to SARS-CoV-2 virus) and GII (173 patients who did not have the virus detected in the test) were most relevant at 3512 cm-1, 3385 cm-1 and 1321 cm-1 after 2nd derivative data transformation. To carry out the diagnostic modeling, chemometrics via FTIR and Discriminant Analysis of Orthogonal Partial Least Squares (OPLS-DA) by salivary transflectance mode with one latent variable and one orthogonal signal correction component were used. The model generated predictions with 100 % sensitivity, specificity and accuracy. With the proposed model, in a single application of an individual's saliva in the FTIR equipment, results related to the detection of SARS-CoV-2 can be obtained in a few minutes of spectral evaluation.

Acceleration of collateral development by carcinoembryonic antigen-related cell adhesion molecule 1 expression on CD11b/⁺Gr-1⁺ myeloid cells--brief report.

OBJECTIVE: Previously, we demonstrated the relevance for endothelial carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) expression in collateral formation. However, a proarteriogenic role for CEACAM1(+) myeloid cells is unknown. Here, we investigated the contribution of CEACAM1(+) myeloid cells on collateral formation. METHODS AND RESULTS: Collateral growth and vascular remodeling were analyzed in CEACAM1-competent and CEACAM1 null mice after femoral artery ligation in hindlimb ischemia. Reperfusion of the adductor muscles was evaluated by Laser Doppler measurements and microcomputed tomography imaging. In CEACAM1 null mice, poor reperfusion and reduced collateral formation were observed, accompanied by reduction in arterial diameters. Using flow cytometry, we identified an increase of the muscle-resident CD11b(+)/granulocyte receptor-1+ (Gr-1+) population in CEACAM1 null mice only, pointing toward a CEACAM1-dependent functional deviation. Direct and reciprocal bone marrow transplantations between CEACAM1-competent and CEACAM1 null mice, and antibody-mediated depletion of the CD11b(+)/Gr-1(+) population, confirmed the requirement of CEACAM1 expression on the CD11b(+)/Gr-1(+) population for reestablishment of perfusion after arterial occlusion. CONCLUSIONS: CEACAM1 expression on CD11b(+)/Gr-1(+) myeloid cells is a prerequisite for adequate collateral formation.

Transgenic over-expression of interleukin-33 in osteoblasts results in decreased osteoclastogenesis.

Interleukin-33 (IL-33) is the most recently identified member of the IL-1 family of cytokines, which is primarily known for its proinflammatory functions. We have previously reported that IL-33 is expressed by bone-forming osteoblasts, and that administration of recombinant IL-33 to bone marrow cultures inhibits their differentiation into bone-resorbing osteoclasts. Likewise, while the inhibitory effect of IL-33 on osteoclast differentiation was fully abolished in cultures lacking the IL-33 receptor ST2, mice lacking ST2 displayed low bone mass caused by increased osteoclastogenesis. Although these data suggested a physiological role of IL-33 as an inhibitor of bone resorption, direct in vivo evidence supporting such a function was still missing. Here we describe the generation and bone histomorphometric analysis of a transgenic mouse model (Col1a1-Il33) over-expressing IL-33 specifically in osteoblasts. While we did not observe differences in osteoblast number and bone formation between wildtype and Col1a1-Il33 mice, the number of osteoclasts was significantly reduced compared to wildtype littermates in two independent transgenic lines. Since we did not observe quantitative differences in the populations of eosinophils, neutrophils, basophils or M2-macrophages from the bone marrow of wildtype and Col1a1-Il33 mice, our data demonstrate that an inhibition of osteoclastogenesis is one of the major physiological functions of IL-33, at least in mice.

Antigen-specificity of oligoclonal abnormal protein bands in multiple myeloma after allogeneic stem cell transplantation.

Myeloma patients may develop oligoclonal immunoglobulins, so-called abnormal protein bands (APB), after stem cell transplantation. APB do not correspond to the patient's paraprotein and confer a good prognosis. We set out to investigate whether such APB represent a humoral anti-myeloma immune response by screening immunoglobulins of 15 myeloma patients after allogeneic stem cell transplantation and a control group of healthy donors for reactivity with myeloma protein extracts. While the immunoglobulins of healthy donors did not react with myeloma protein extracts, patient-derived immunoglobulins showed variable levels of interaction, depending on the presence of APB on immunofixation. Most commonly, we detected interactions with heat-shock proteins, followed by neutral alpha-glucosidase, alpha-enolase and vimentin, as well as proliferating cell nuclear antigen and MAGEA4. More than 80% of targets were upregulated in myeloma. Heat-shock protein 60 (HSP60) was subsequently evaluated as an exemplary antigen. We found that HSP60 was aberrantly displayed on the surface of primary myeloma cells. Indeed, patient-derived APB-containing immunoglobulins recognized surface HSP60 suggesting that this antigen becomes accessible to the immune system after aberrant membrane exposition. We conclude that immunoglobulin fractions with APB recognize recurrent myeloma antigens and that this humoral response may contribute to the more favorable prognosis in patients with APB.

Assessment of oxidative parameters in rat spinal cord after chronic constriction of the sciatic nerve.

Although reactive oxygen species (ROS) are involved in neuropathic pain, the direct relationship between these species and chronic constriction of sciatic nerve (CCI) has not been studied in spinal cord. Thus, this study induced CCI in rats and these animals were sacrificed 3 and 10 days after the surgical procedure to determine the superoxide dismutase (SOD) and catalase activities, as well as ascorbic acid, hydrogen peroxide (H(2)O(2)) and lipid hydroperoxide levels in lumbosacral spinal cord. Von Frey Hair and hot plate tests were performed to assess the degree of mechanical and thermal hyperalgesia at days 0, 3 and 10. The results showed that CCI significantly induced mechanical and thermal hyperalgesia at days 3 and 10. Parallel there was increase in spinal cord lipid hydroperoxide at days 3 and 10 in rats submitted to CCI. In Sham rats a significant increase in this parameter occurred at day 10. H(2)O(2) decreased at day 10 only in CCI group. SOD activity was decreased in Sham and CCI groups at day 3, while catalase activity was increased in CCI rats at days 3 and 10. Ascorbic acid levels were reduced only in CCI rats at day 3. Although the role of such changes is unclear, many were not specific to neuropathic pain and the differences could be related to different degrees of central sensitization in Sham and CCI rats.

Effect of high-velocity, low-amplitude treatment on superoxide dismutase and glutathione peroxidase activities in erythrocytes from men with neck pain.

OBJECTIVE: This study investigates the analgesic effect of high-velocity, low-amplitude (HVLA) manipulation and antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GPx) in erythrocytes of men with neck pain. METHODS: Twenty-two men with neck pain of mechanical origin who were aged 20 to 50 years, were nonsmokers, had a sedentary lifestyle, had no comorbidities, and were not in adjuvant therapy underwent 6 sessions of HVLA chiropractic manipulation 3 times a week for 2 weeks. Patients were treated by the same chiropractor and under the same conditions. Blood samples were collected before the beginning of the treatment and at the end of the third and last session. Erythrocytes were separated from blood and then processed to determine SOD and GPx activities. The quadruple visual scale and the Neck Disability Index were used to demonstrate the analgesic effect of treatment. The results were analyzed by repeated-measures analysis of variance followed by Bonferroni posttest. Differences were considered significant when P was less than .05. RESULTS: Despite the tendency to reduction in SOD and increase in GPx activities, there was no significant change after the treatment. CONCLUSION: High-velocity, low-amplitude treatment for 6 sessions in men with neck pain did not affect systemic SOD and GPx activities. Despite the absence of significant changes, this study is important because it is the first to investigate the activities of SOD and GPx in patients with neck pain treated with HVLA spinal manipulation.

TNF in the liver: targeting a central player in inflammation.

Tumour necrosis factor-α (TNF) is a multifunctional cytokine. First recognized as an endogenous soluble factor that induces necrosis of solid tumours, TNF became increasingly important as pro-inflammatory cytokine being involved in the immunopathogenesis of several autoimmune diseases. In the liver, TNF induces numerous biological responses such as hepatocyte apoptosis and necroptosis, liver inflammation and regeneration, and autoimmunity, but also progression to hepatocellular carcinoma. Considering these multiple functions of TNF in the liver, we propose anti-TNF therapies that specifically target TNF signalling at the level of its specific receptors.

CEACAM1+ myeloid cells control angiogenesis in inflammation.

Local inflammation during cutaneous leishmaniasis is accompanied by accumulation of CD11b(+) cells at the site of the infection. A functional role for these monocytic cells in local angiogenesis in leishmaniasis has not been described so far. Here, we show that CD11b(+) cells express high levels of the myeloid differentiation antigen carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1). In experimental cutaneous leishmaniasis in C57BL/6 wild-type (B6.WT) and B6.Ceacam1(-/-) mice, we found that only B6.Ceacam1(-/-) mice develop edemas and exhibit impairment of both hemangiogenesis and lymphangiogenesis. Because CEACAM1 expression correlates with functional angiogenesis, we further analyzed the role of the CD11b(+) population. In B6.Ceacam1(-/-) mice, we found systemic reduction of Ly-6C(high)/CD11b(high) monocyte precursors. To investigate whether CEACAM1(+) myeloid cells are causally related to efficient angiogenesis, we used reverse bone marrow transplants (BMTs) to restore CEACAM1(+) or CEACAM1(-) bone marrow in B6.Ceacam1(-/-) or B6.WT recipients, respectively. We found that angiogenesis was restored by CEACAM1(+) BMT only. In addition, we observed reduced morphogenic potential of inflammatory cells in Matrigel implants in CEACAM1(-) backgrounds or after systemic depletion of CD11b(high) macrophages. Taken together, we show for the first time that CEACAM1(+) myeloid cells are crucial for angiogenesis in inflammation.

Antigen presentation, autoantibody production, and therapeutic targets in autoimmune liver disease.

The liver is an important immunological organ that controls systemic tolerance. The liver harbors professional and unconventional antigen-presenting cells that are crucial for tolerance induction and maintenance. Orchestrating the immune response in homeostasis depends on a healthy and well-toned immunological liver microenvironment, which is maintained by the crosstalk of liver-resident antigen-presenting cells and intrahepatic and liver-infiltrating leukocytes. In response to pathogens or autoantigens, tolerance is disrupted by unknown mechanisms. Intrahepatic parenchymal and nonparenchymal cells exhibit unique antigen-presenting properties. The presentation of microbial and endogenous lipid-, metabolite- and peptide-derived antigens from the gut via conventional and nonconventional mechanisms can educate intrahepatic immune cells and elicit effector responses or tolerance. Perturbation of this balance results in autoimmune liver diseases, such as autoimmune hepatitis, primary biliary cholangitis, and primary sclerosing cholangitis. Although the exact etiologies of these autoimmune liver diseases are unknown, it is thought that the disruption of tolerance towards self-antigens and microbial metabolites and lipids, as well as alterations in bile acid composition, may result in changes in effector cell activation and polarization and may reduce or impair protective anti-inflammatory regulatory T and B cell responses. Additionally, the canonical and noncanonical transmission of antigens and antigen:MHC complexes via trogocytosis or extracellular vesicles between different (non) immune cells in the liver may play a role in the induction of hepatic inflammation and tolerance. Here, we summarize emerging aspects of antigen presentation, autoantibody production, and the application of novel therapeutic approaches in the characterization and treatment of autoimmune liver diseases.

TAE226-mediated inhibition of focal adhesion kinase interferes with tumor angiogenesis and vasculogenesis.

Neoangiogenesis plays an important role in tumor growth and metastasis. Evaluation of new anti-angiogenic targets may broaden the armament for future therapeutic concepts. Focal adhesion kinase (FAK), expressed in endothelial and tumor cells, is essential for adhesion and mobility of adherent cells. In the current study we analyzed the anti-angiogenic properties of the FAK inhibitor TAE226 on the proliferation of blood outgrowth endothelial cell (OEC) and differentiation of endothelial progenitor cells (EPC), derived from peripheral blood CD133(+) cells, tube formation and on neovascularization in a HT29 xenotransplant model. The effects of TAE226 were compared to those of the rapamycin analogue RAD001. The combination of both drugs was also studied. We showed that HT29 tumor cells and OEC were most sensitive to the action of TAE226 compared to EPC in vitro. In contrast, RAD001 affected the proliferation of both types of endothelial cells stronger than that of HT29 cells. Furthermore we could show that TAE226 inhibited tube formation in a dose dependent manner. In a HT29 subcutaneous tumor model TAE226 and RAD001 diminished MVD at commonly employed doses to a similar degree. Combination of both compounds did not show synergy in vitro or in vivo. Since TAE226 has been shown to inhibit the PI3 kinase, Akt kinase, mTor pathway, addition of RAD001 may not increase this effect. In conclusion, we have shown that treatment with TAE leads to a reduction of neoangiogenesis in vitro and in a mouse model. The effects are mediated by inhibition of angiogenesis and vasculogenic OEC and EPC.