Intravenous immune globulin suppresses angiogenesis in mice and humans

Therapeutic targeting of telomerase ameliorates experimental choroidal neovascularization

Choroidal neovascularization (CNV) is the principal driver of blindness in neovascular age-related macular degeneration (nvAMD). Increased activity of telomerase, has been associated with endothelial cell proliferation, survival, migration, and invasion in the context of tumor angiogenesis. Expanding on this knowledge, we investigated the role of telomerase in the development of CNV in mouse model. We observed increased gene expression and activity of telomerase in mouse CNV. Genetic deficiency of the telomerase components, telomerase reverse transcriptase (Tert) and telomerase RNA component (Terc) suppressed laser-induced CNV in mice. Similarly, a small molecule inhibitor of TERT (BIBR 1532), and antisense oligonucleotides (ASOs) targeting Tert and Terc reduced CNV growth. Bone marrow chimera studies suggested that telomerase activity in non-bone marrow-derived cells is crucial for the development of CNV. Comparison of BIBR 1532 with VEGF neutralizing therapeutic strategy in mouse revealed a comparable level of angiosuppressive activity. However, when BIBR and anti-VEGF antibodies were administered as a combination at sub-therapeutic doses, a statistically significant suppression of CNV was observed. These findings underscore the potential benefits of combining sub-therapeutic doses of BIBR and anti-VEGF antibodies for developing newer therapeutic strategies for NV-AMD. Telomerase inhibition with BIBR 1532 suppressed induction of multiple cytokines and growth factors critical for neovascularization. In conclusion, our study identifies telomerase as a promising therapeutic target for treating neovascular disease of the eye and thus provides a proof of principle for further exploration of telomerase inhibition as a novel treatment strategy for nvAMD.

Neuroprotective Effect of Polyvalent Immunoglobulins on Mouse Models of Chemotherapy-Induced Peripheral Neuropathy

The occurrence of neuropathic pain in chemotherapy-induced peripheral neuropathy (CIPN) is a major dose-limiting effect of many commonly-used anticancer agents. Polyvalent human immunoglobulins (hIg), used in the treatment of several peripheral neuropathies, may alleviate neuropathic pain. The aim of this project was to investigate the preventive effect of hIg in two mouse models of CIPN, induced by vincristine (VCR, 100 µg/kg/d) and oxaliplatin (OXP, 6 mg/kg/3d). Human Ig were administered one day before the first injection of chemotherapy. The onset of CIPN and effects of hIg were assessed via functional tests and morphological analyses of sensory nerves. To evaluate the effect of hIg on chemotherapy cytotoxicity, viability assays were performed using hIg (0 to 12 mg/mL) combined with anticancer agents on human cancer cell lines. The preventive treatment with hIg alleviated tactile hypersensitivity and nerve injuries induced by VCR. It also alleviated tactile/cold hypersensitivities and nerve injuries induced by OXP. Treatment with hIg did not affect the cytotoxicity of either chemotherapy. Furthermore, in combination with VCR, hIg potentiated chemo-induced cell death. In conclusion, hIg is a promising therapy to prevent the onset of CIPN and potentiate chemotherapy effect on cancer, reinforcing the interest in hIg in the management of CIPN.

Successful Emergency Management of a Dog with Ventilator-Dependent Acquired Myasthenia Gravis with Immunoadsorption

A one-year-old, female intact Samoyed, 12.5 kg, was presented with coughing for 2 weeks, progressive appendicular and axial muscle weakness, megaesophagus and labored breathing for 5 days. There was no improvement with standard treatment. Acquired myasthenia gravis was suspected and the dog was referred with increasing dyspnea. At presentation, the dog showed a severely reduced general condition, was non-ambulatory and showed abdominal and severely labored breathing. A marked hypercapnia (PvCO2 = 90.1 mmHg) was present in venous blood gas analysis. The serum anti-acetylcholine receptor antibody test was consistent with acquired myasthenia gravis (2.1 nmol/L). The dog was anesthetized with propofol and mechanically ventilated with a Hamilton C1 ventilator. Immunoadsorption was performed with the COM.TEC® and ADAsorb® platforms and a LIGASORB® adsorber to eliminate anti-acetylcholine receptor antibodies. Local anticoagulation was performed with citrate. Treatment time for immunoadsorption was 1.5 h with a blood flow of 50 mL/min. A total plasma volume of 1.2 L was processed. Further medical treatment included intravenous fluid therapy, maropitant, esomeprazole, antibiotic therapy for aspiration pneumonia and neostigmine 0.04 mg/kg intramuscularly every 6 h for treatment of acquired myasthenia gravis. Mechanical ventilation was stopped after 12 h. A percutaneous gastric feeding tube was inserted under endoscopic control on day 2 for further medical treatment and nutrition. A second treatment with immunoadsorption was performed on day 3. Again, a total plasma volume of 1.2 L was processed. Immediately after this procedure, the dog regained muscle strength and was able to stand and to walk. After 6 days, the dog was discharged from the hospital. This is the first report of immunoadsorption for emergency management of a dog with acute-fulminant acquired myasthenia gravis. Immunoadsorption may be an additional option for emergency treatment in dogs with severe signs of acquired myasthenia gravis.

The Evolving Landscape of B Cells in Cancer Metastasis

Metastasis is the leading cause of cancer mortality. Functional and clinical studies have documented diverse B-cell and antibody responses in cancer metastasis. The presence of B cells in tumor microenvironments and metastatic sites has been associated with diverse effects that can promote or inhibit metastasis. Specifically, B cells can contribute to the spread of cancer cells by enhancing tumor cell motility, invasion, angiogenesis, lymphangiogenesis, and extracellular matrix remodeling. Moreover, they can promote metastatic colonization by triggering pathogenic immunoglobulin responses and recruiting immune suppressive cells. Contrastingly, B cells can also exhibit antimetastatic effects. For example, they aid in enhanced antigen presentation, which helps activate immune responses against cancer cells. In addition, B cells play a crucial role in preventing the dissemination of metastatic cells from the primary tumor and secrete antibodies that can aid in tumor recognition. Here, we review the complex roles of B cells in metastasis, delineating the heterogeneity of B-cell activity and subtypes by metastatic site, antibody class, antigen (if known), and molecular phenotype. These important attributes of B cells emphasize the need for a deeper understanding and characterization of B-cell phenotypes to define their effects in metastasis.

Safety of Immunomodulatory Systemic Therapies Used in the Management of Immune-Related Cutaneous Adverse Events

Immune-related cutaneous adverse events (ircAEs) commonly occur in patients on treatment with immune checkpoint inhibitors and can significantly reduce patient quality of life. These are often treated with immunomodulatory agents, including glucocorticoids, immunosuppressants, and biologics. While often effective at managing symptoms, these therapies can cause several adverse events which may limit their use. In addition, immunomodulatory agents should be used with particular caution in patients receiving immunotherapy, as the efficacy of the oncologic regimen may potentially be undermined. In this review, we summarize the safety of systemic therapies that are used in the management of ircAEs, with a particular focus on the resultant risk of secondary tumor progression in patients with active cancer.

A Charge Variant of Bevacizumab Offers Enhanced FcRn-Dependent Pharmacokinetic Half-Life and Efficacy

BACKGROUND

Lysine variants of monoclonal antibodies (mAbs) result from incomplete clipping of the C-terminal lysine residues of the heavy chain. Although the structure of the lysine variants has been determined for several mAb products, a detailed study that investigates the impact of lysine charge variants on PK/PD and preclinical safety is yet to be published.

OBJECTIVE

An in-depth investigation of the impact of C- terminal lysine clipping of mAbs on safety and efficacy for bevacizumab charge variants.

METHOD

Charge variant isolation using semi-preparative chromatography is followed by a comparative analysis of FcRn binding, pharmacokinetics, and pharmacodynamics in relevant animal models.

RESULTS

K1 variant exhibited improved FcRn binding affinity (4-fold), half-life (1.3-fold), and anti-tumor activity (1.3-fold) as compared to the K0 (main) product. However, the K2 variant, even though exhibited higher FcRn affinity (2-fold), displayed lower half-life (1.6-fold) and anti-tumor activity at medium and low doses. Differential proteomic analysis revealed that seven pathways (such as glycolysis, gluconeogenesis, carbon metabolism, synthesis of amino acids) were significantly enriched. Higher efficacy of the K1 variant is likely due to higher bioavailability of the drug, leading to complete downregulation of the pathways that facilitate catering of the energy requirements of the proliferating tumor cells. On the contrary, the K2 variant exhibits a shorter half-life, resulting only in partial reduction in the metabolic/energy requirements of the growing tumor cells.

CONCLUSION

Overall, we conclude that the mAb half-life, dosage, and efficacy of a biotherapeutic product are significantly impacted by the charge variant profile of a biotherapeutic product.

Dietary quercetin and vitamin E supplementation modulates the reproductive performance and antioxidant capacity of aged male breeder chickens

Aged male chickens experience rapid declines in spermatogenesis, antioxidant capacity, immunity, and hormone synthesis. Vitamin E plays a significant role in reproduction, nervous system function, and disease resistance in animals. Quercetin also exerts many biological effects, such as antioxidant ability, immunostimulation, and protection of spermatozoal plasma membranes. This study evaluated the effects of combining dietary quercetin (Q) and vitamin E (VE) on sperm quality, antioxidant capacity, immunity, and expression of genes related to spermatogenesis, immunity, apoptosis, and inflammation in aged male chickens. A total of 120 Tianfu breeder male chickens (65 wk old) were randomly allotted to 4 treatments with 3 replicates (10 birds each). The birds were fed diets containing Q (0.4g/kg), VE (0.2g/kg), Q+VE (0.4g/kg + 0.2g/kg), and a basal diet for 11 wk. At the end of the experimental period, blood, semen, liver, testes, and spleen samples were collected from 2 birds per replicate. Serum hormones, antioxidant parameters, cytokines, and immunoglobulins were evaluated; and the mRNA expression of genes related to spermatogenesis, apoptosis, and inflammation are determined in the testes and liver tissues.

The results showed that the combination quercetin and vitamin E significantly promoted the sperm count and motility, as well as elevated the levels of testosterone, follicle-stimulating hormone, and luteinizing hormone, antioxidant enzymes (Superoxide dismutase, Glutathione, and Total antioxidant capacity), and serum immunoglobulins (IgA and IgM) in the aged male chickens; also Q+VE showed protective effects on the liver against injury. In addition, Q+VE significantly increased the expression of genes related to spermatogenesis (AR, pgk2, Cyclin A1, and Cyclin A2), immunity (IFN-γ and IL-2), and anti-inflammatory cytokines (IL-10) (P < 0.05), whereas the expression of proinflammatory cytokines (IL-1β and IL-6) was decreased (P < 0.05). Taken together, these data indicate that the combination of quercetin and vitamin E improved reproductive characteristics such as spermatogenesis, sperm quality, and hormone regulation, as well as promoted antioxidant defense, hepatoprotective capacity, and immune response in aged male chickens without any detrimental effects.

Loss of Id3 (Inhibitor of Differentiation 3) Increases the Number of IgM-Producing B-1b Cells in Ischemic Skeletal Muscle Impairing Blood Flow Recovery During Hindlimb Ischemia

OBJECTIVE

Neovascularization can maintain and even improve tissue perfusion in the setting of limb ischemia during peripheral artery disease. The molecular and cellular mechanisms mediating this process are incompletely understood. We investigate the potential role(s) for Id3 (inhibitor of differentiation 3) in regulating blood flow in a murine model of hindlimb ischemia (HLI). Approach and Results: HLI was modeled through femoral artery ligation and resection and blood flow recovery was quantified by laser Doppler perfusion imaging. Mice with global Id3 deletion had significantly impaired perfusion recovery at 14 and 21 days of HLI. Endothelial- or myeloid cell-specific deletion of Id3 revealed no effect on perfusion recovery while B-cell-specific knockout of Id3 (Id3BKO) revealed a significant attenuation of perfusion recovery. Flow cytometry revealed no differences in ischemia-induced T cells or myeloid cell numbers at 7 days of HLI, yet there was a significant increase in B-1b cells in Id3BKO. Consistent with these findings, ELISA (enzyme-linked immunoassay) demonstrated increases in skeletal muscle and plasma IgM. In vitro experiments demonstrated reduced proliferation and increased cell death when endothelial cells were treated with conditioned media from IgM-producing B-1b cells and tibialis anterior muscles in Id3BKO mice showed reduced density of total CD31+ and αSMA+CD31+ vessels.

CONCLUSIONS

This study is the first to demonstrate a role for B-cell-specific Id3 in maintaining blood flow recovery during HLI. Results suggest a role for Id3 in promoting blood flow during HLI and limiting IgM-expressing B-1b cell expansion. These findings present new mechanisms to investigate in peripheral artery disease pathogenesis.

Low levels of organic compound trace elements improve the eggshell quality, antioxidant capacity, immune function, and mineral deposition of aged laying hens

In the egg production industry, trace elements are required as additional dietary supplements to play vital roles in performance and egg quality. Compared to inorganic microelements (ITs), appropriate dose of organic trace microelements (OTs) are environmentally friendly and sufficient to satisfy the needs of hens. In order to evaluate the extent to which low-dose OTs replace whole ITs, the effects of organic copper, zinc, manganese, and iron compound on the performance, eggshell quality, antioxidant capacity, immune function, and mineral deposition of old laying hens were investigated. A total of 1 080 57-week-old Jing Hong laying hens were assigned to five groups with six replicates of 36 layers each for an 8-week experimental period. The birds were fed either a basal diet (control treatment (CT)) or the basal diet supplemented with commercial levels of inorganic trace elements (IT 100%) or the equivalent organic trace elements at 20%, 30%, and 50% of the inorganic elements (OT 20%, OT 30%, and OT 50%, respectively). Results showed that compared with those in the CT treatment, feeding hens with inorganic or organic microelement diet had significant effects on the eggshell quality, antioxidant capacity, immune function, and mineral deposition of old laying hens (P < 0.05). The eggshell strength and ratio between OT 30%, OT 50%, and IT 100% were similar at weeks 4 and 8, and the eggshell thickness of these groups was also similar at weeks 6 and 8. At week 8, the eggshell colour in OT 50% was darker than that in IT 100%. The mineral content in the eggshells of OT 50% and IT 100% significantly increased (P < 0.001), with no significant difference in effective thickness, mammillary thickness, and mammillary knob width between groups. There were no differences in the malondialdehyde content, total antioxidant capacity, and total superoxide dismutase activity in serum between OT 30%, OT 50%, and IT100%. While the catalase activities, the interleukin-1β, interleukin-10, immunoglobulin G, and immunoglobulin M concentrations in serum were not significantly different between OT 50% and IT 100%. The mineral contents in the faeces of the organic groups were considerably reduced compared with those in IT 100% (P < 0.001). In conclusion, dietary supplementation with 30-50% organic compound microelements has the potential to replace 100% inorganic microelements in the hen industry for improving eggshell quality, mineral deposition in the eggshell, antioxidant capacity, and immune function, and reducing emissions to the environment without negative effects on laying performance.

Synergistic effects of quercetin and vitamin E on egg production, egg quality, and immunity in aging breeder hens

Laying hens experience a rapid decline in egg production, egg quality, and immunity, usually at the end of the peak laying period. Quercetin, a known flavonoid, exerts biological activities, including phytoestrogenic, immunity, antibiotic, antioxidant, and anti-inflammatory properties. Vitamin E also shows egg production and immunoregulatory potential in animals. This study evaluated the capacity of dietary quercetin, vitamin E, and the combination of both, to promote egg production and egg quality, and to improve the immunity of aging breeder hens. We also elucidated how quercetin and vitamin E combination could synergistically affect egg production, egg quality, and immunity in aging breeder hens. A total of 400 Tianfu broiler breeders at the age of 52 wk were randomly allotted to 4 treatments with 4 replicates, 100 hens per treatment and 25 hens per replicate. They were fed diets containing quercetin at 0.4 g/kg, Vitamin E (200 mg/kg), quercetin and vitamin E (0.4 g/kg and 200 mg/kg), and a basal diet (control) for a period 10 wk. Daily feed intake and egg production rate were recorded, and weekly records were recorded on egg quality tests. At the end of the 10-wk experimental period, blood samples and immune organ (spleen) were collected from 2 birds per replicate, totaling 32 birds. Feed intake, immune organ index, serum cytokines, and immunoglobulins were evaluated, and the mRNA expression of genes related to immunity was determined from the spleen tissue. Generally, the results showed that separately or as a combination, supplemental quercetin and vitamin E significantly improved performance and egg quality (P < 0.05), and significantly increased serum immunoglobulins (IgA, IgM, and IgG) and cytokines (IFN-γ and IL-2) concentrations, as well as promoted immune organ development and index, and promoted the expression of splenic immune-related genes (IL-2 and INF-γ) (P < 0.05), compared with the control. It was confirmed in this study that the combination of quercetin and vitamin E exert synergistic effects on egg production, egg quality, and immune function in aging hens.

Use of Human Intravenous Immunoglobulin in Veterinary Clinical Practice

Therapy with human intravenous immunoglobulin (hIVIG) as an immunomodulator in veterinary patients results in effective but transient immunosuppression, and may be viable as part of a multidrug strategy against immune-mediated thrombocytopenia and autoimmune cutaneous disease. Efficacy of hIVIG against other veterinary autoimmune diseases is questionable. Veterinary patients tolerate hIVIG therapy well, with few infusion reactions documented. Veterinary clinical trials of hIVIG are limited, and more work is needed to determine the true efficacy and risk of hIVIG administration in companion animals.

Quercetin improves immune function in Arbor Acre broilers through activation of NF-κB signaling pathway

Quercetin, the main component of flavonoids, has a wide range of biological actions. Quercetin can be made into a variety of additives for practice, because of the stable chemical structure and water-soluble derivatives. This study was intended to explore the effects of quercetin on immune function and its regulatory mechanism in Arbor Acre broiler to provide a practical basis for improving poultry immune function and figure out the optimum supplementation as functional feed additives. A total of 240 one-day-old healthy Arbor Acre broilers, similar in body weight, were randomly allotted to 4 treatments with 6 replicates, 10 broilers in each replicate and fed with diets containing quercetin at 0, 0.02, 0.04, and 0.06% for 6 wk. Blood and immune organs (spleen, thymus, and bursa) were collected from chickens at the end of the experiment. Growth performance, immune organs indexes, contents of serum immune molecules, splenic T lymphocyte proliferative responses, and expression of immune related genes were evaluated. The results showed that dietary quercetin had no significant effect (P > 0.05) on growth performance of broilers. Compared with control, 0.06% quercetin supplementation in diet significantly increased spleen index and thymus index (P < 0.05). It also increased the secretion of immune molecules including immunoglobulin A (IgA), interleukin-4 (IL-4) (P < 0.001), immunoglobulin M (IgM) (P = 0.007), complement component 4 (C4) (P = 0.001), and tumor necrosis factor-α (TNF-α) (P < 0.05). On the other hand, 0.02% quercetin supplementation significantly increased complement component 3 (C3) (P < 0.05). Additionally, both 0.04 and 0.06% quercetin supplementation significantly increased expression of TNF-α, TNF receptor associated factor-2 (TRAF-2), TNF receptor superfamily member 1B (TNFRSF1B), nuclear factor kappa-B p65 subunit (NF-κBp65), and interferon-γ (IFN-γ) mRNA (P < 0.05), and expression of NF-κB inhibitor-alpha (IκB-α) mRNA were significantly decreased (P < 0.05). Thus, quercetin improved immune function via NF-κB signaling pathway triggered by TNF-α.

Exploring the Immunological Mechanisms Underlying the Anti-vascular Endothelial Growth Factor Activity in Tumors

Several studies report the key role of the vascular endothelial growth factor (VEGF) signaling on angiogenesis and on tumor growth. This has led to the development of a number of VEGF-targeted agents to treat cancer patients by disrupting the tumor blood vessel supply. Of them, bevacizumab, an FDA-approved humanized monoclonal antibody against VEGF, is the most promising. Although the use of antibodies targeting the VEGF pathway has shown clinical benefits associated with a reduction in the tumor blood vessel density, the inhibition of VEGF-driven vascular effects is only part of the functional mechanism of these therapeutic agents in the tumor ecosystem. Compelling reports have demonstrated that VEGF confers, in addition to the activation of angiogenesis-related processes, immunosuppressive properties in tumors. It is also known that structural remodeling of the tumor blood vessel bed by anti-VEGF approaches affect the influx and activation of immune cells into tumors, which might influence the therapeutic results. Besides that, part of the therapeutic effects of antiangiogenic antibodies, including their role in the tumor vascular network, might be triggered by Fc receptors in an antigen-independent manner. In this mini-review, we explore the role of VEGF inhibitors in the tumor microenvironment with focus on the immune system, discussing around the functional contribution of both bevacizumab's Fab and Fc domains to the therapeutic results and the combination of bevacizumab therapy with other immune-stimulatory settings, including adjuvant-based vaccine approaches.

Nonspecific immunoglobulin G is effective in preventing and treating cancer in mice

BACKGROUND

Previous accidental findings showed that administration of immunoglobulin G (IgG) in treating autoimmune diseases was able to inhibit cancers that happened to grow in these patients. However, such treatment has not been used to treat cancer patients clinically. The mechanism and optimal dosages of this treatment have not been established. Subsequent animal experiments confirmed this effect, but all previous studies in animal models used human IgG which was heterogeneous to the animal hosts and therefore could adversely interfere with the results.

MATERIALS AND METHODS

We tested different dosages of mouse IgG in treating and preventing three syngeneic cancer types (melanoma, colon cancer, and breast cancer) in three immune potent mouse models. The expression of Ki67, CD34, VEGF, MMPs, and cytokines in tumor tissues were examined with immunohistochemistry or quantitative real-time PCR to evaluate tumor proliferation, vascularization, metastasis, and proinflammatory response in the tumor microenvironment.

RESULTS

We found that low-dose IgG could effectively inhibit cancer progression, regulate tumor vessel normalization, and prolong survival. Administration of IgG before cancer cell inoculation could also prevent the development of cancer. In addition, IgG caused changes in a number of cytokines and skewed macrophage polarization toward M1-like phenotype, characterized by proinflammatory activity and inhibition of proliferation of cancer cells.

CONCLUSION

Our findings suggest that nonspecific IgG at low dosages could be a promising candidate for cancer prevention and treatment.

New Therapies of Neovascular AMD-Beyond Anti-VEGFs

Neovascular age-related macular degeneration (nAMD) is one of the leading causes of blindness among the aging population. The current treatment options for nAMD include intravitreal injections of anti-vascular endothelial growth factor (anti-VEGF). However, standardized frequent administration of anti-VEGF injections only improves vision in approximately 30–40% of nAMD patients. Current therapies targeting nAMD pose a significant risk of retinal fibrosis and geographic atrophy (GA) development in nAMD patients. A need exists to develop new therapies to treat nAMD with effective and long-term anti-angiogenic effects. Recent research on nAMD has identified novel therapeutic targets and angiogenic signaling mechanisms involved in its pathogenesis. For example, tissue factor, human intravenous immune globulin, interferon-β signaling, cyclooxygenase-2 (COX-2) and cytochrome P450 monooxygenase lipid metabolites have been identified as key players in the development of angiogenesis in AMD disease models. Furthermore, novel therapies such as NACHT, LRR and PYD domains containing protein 3 (NLRP3) inflammasome inhibition, inhibitors of integrins and tissue factor are currently being tested at the level of clinical trials to treat nAMD. The aim of this review is to discuss the scope for alternative therapies proposed as anti-VEGFs for the treatment of nAMD.

Engineering liposomal nanoparticles for targeted gene therapy

Recent mechanistic studies have attempted to deepen our understanding of the process by which liposome-mediated delivery of genetic material occurs. Understanding the interactions between lipid nanoparticles and cells is still largely elusive. Liposome-mediated delivery of genetic material faces systemic obstacles alongside entry into the cell, endosomal escape, lysosomal degradation and nuclear uptake. Rational design approaches for targeted delivery have been developed to reduce off-target effects and enhance transfection. These strategies, which have included the modification of lipid nanoparticles with target-specific ligands to enhance intracellular uptake, have shown significant promise at the proof-of-concept stage. Control of physical and chemical specifications of liposome composition, which includes lipid-to-DNA charge, size, presence of ester bonds, chain length and nature of ligand complexation, is integral to the performance of targeted liposomes as genetic delivery agents. Clinical advances are expected to rely on such systems in the therapeutic application of liposome nanoparticle-based gene therapy. Here, we discuss the latest breakthroughs in the development of targeted liposome-based agents for the delivery of genetic material, paying particular attention to new ligand and cationic lipid design as well as recent in vivo advances.

Molecular Checkpoint Decisions Made by Subverted Vascular Niche Transform Indolent Tumor Cells into Chemoresistant Cancer Stem Cells

Tumor-associated endothelial cells (TECs) regulate tumor cell aggressiveness. However, the core mechanism by which TECs confer stem cell-like activity to indolent tumors is unknown. Here, we used in vivo murine and human tumor models to identify the tumor-suppressive checkpoint role of TEC-expressed insulin growth factor (IGF) binding protein-7 (IGFBP7/angiomodulin). During tumorigenesis, IGFBP7 blocks IGF1 and inhibits expansion and aggresiveness of tumor stem-like cells (TSCs) expressing IGF1 receptor (IGF1R). However, chemotherapy triggers TECs to suppress IGFBP7, and this stimulates IGF1R⁺ TSCs to express FGF4, inducing a feedforward FGFR1-ETS2 angiocrine cascade that obviates TEC IGFBP7. Thus, loss of IGFBP7 and upregulation of IGF1 activates the FGF4-FGFR1-ETS2 pathway in TECs and converts naive tumor cells to chemoresistant TSCs, thereby facilitating their invasiveness and progression.

Nanofibers for improving the wound repair process: the combination of a grafted chitosan and an antioxidant agent

Wound healing, a complex process involving several important biomolecules and pathways, requires efficient dressings to enhance the therapy effects.

HDL activation of endothelial sphingosine-1-phosphate receptor-1 (S1P1) promotes regeneration and suppresses fibrosis in the liver

Regeneration of hepatic sinusoidal vasculature is essential for non-fibrotic liver regrowth and restoration of its metabolic capacity. However, little is known about how this specialized vascular niche is regenerated. Here we show that activation of endothelial sphingosine-1-phosphate receptor-1 (S1P₁) by its natural ligand bound to HDL (HDL-S1P) induces liver regeneration and curtails fibrosis. In mice lacking HDL-S1P, liver regeneration after partial hepatectomy was impeded and associated with aberrant vascular remodeling, thrombosis and peri-sinusoidal fibrosis. Notably, this "maladaptive repair" phenotype was recapitulated in mice that lack S1P₁ in the endothelium. Reciprocally, enhanced plasma levels of HDL-S1P or administration of SEW2871, a pharmacological agonist specific for S1P₁ enhanced regeneration of metabolically functional vasculature and alleviated fibrosis in mouse chronic injury and cholestasis models. This study shows that natural and pharmacological ligands modulate endothelial S1P₁ to stimulate liver regeneration and inhibit fibrosis, suggesting that activation of this pathway may be a novel therapeutic strategy for liver fibrosis.

Human IgG1 antibodies suppress angiogenesis in a target-independent manner

Aberrant angiogenesis is implicated in diseases affecting nearly 10% of the world’s population. The most widely used anti-angiogenic drug is bevacizumab, a humanized IgG1 monoclonal antibody that targets human VEGFA. Although bevacizumab does not recognize mouse Vegfa, it inhibits angiogenesis in mice. Here we show bevacizumab suppressed angiogenesis in three mouse models not via Vegfa blockade but rather Fc-mediated signaling through FcγRI (CD64) and c-Cbl, impairing macrophage migration. Other approved humanized or human IgG1 antibodies without mouse targets (adalimumab, alemtuzumab, ofatumumab, omalizumab, palivizumab and tocilizumab), mouse IgG2a, and overexpression of human IgG1-Fc or mouse IgG2a-Fc, also inhibited angiogenesis in wild-type and FcγR humanized mice. This anti-angiogenic effect was abolished by Fcgr1 ablation or knockdown, Fc cleavage, IgG-Fc inhibition, disruption of Fc-FcγR interaction, or elimination of FcRγ-initated signaling. Furthermore, bevacizumab’s Fc region potentiated its anti-angiogenic activity in humanized VEGFA mice. Finally, mice deficient in FcγRI exhibited increased developmental and pathological angiogenesis. These findings reveal an unexpected anti-angiogenic function for FcγRI and a potentially concerning off-target effect of hIgG1 therapies.