Untreated Control Mice Research Articles

In vivo efficacy of single phage versus phage cocktail in resolving burn wound infection in BALB/c mice

Klebsiella pneumoniae is one of the most predominant pathogens associated with burn wound infections, causing considerable morbidity and mortality. The indiscriminate usage of antibiotics has led to the development of resistant strains, which have contributed towards the inefficacy of antibiotics. Phage therapy is a promising alternative to hinder the progression of pathogenic bacteria. However, phage bacterial resistance is already well known but the use of phage cocktails can overcome this drawback. The aim of the study was to evaluate the therapeutic efficacy of monophage (Kpn1, Kpn2, Kpn3, Kpn4 and Kpn5) in comparison to phage cocktail in resolving the course of burn wound infection in mice. Although, animals receiving monophage therapy exhibited efficacy in resolving the course of infection but phage cocktail was highly effective in arresting the entire infection process (bacterial load, wound contraction, skin myeloperoxidase activity, collagen formation and histopathological analysis).In comparison to untreated control mice, a significant reduction in bacterial load to 4.32, 4.64, 4.42, 4.11 and 4.27 log CFU/ml in Kpn1, Kpn2, Kpn3 Kpn4 and Kpn5 treated animals was obtained respectively was on peak day (3rd day). However, the group receiving phage cocktail (group 7) showed maximum reduction in bacterial load in the skin tissue. The bacterial load was significantly reduced to 3.01 log CFU/ml on peak day. This accounts for a significant reduction of 6 log cycles (p < 0.01) as compared to that of untreated control animals where a peak of 8.81 log CFU/ml was seen followed by steady decrease thereafter. Thus, phage cocktail gave maximum protection against burn wound infection by K. pneumoniae B5055. Compared to any single phage, phage cocktail significantly checked the emergence of resistant mutants. Hence this approach can serve as an effective strategy in treating Klebsiella mediated burn wound infections in individuals who do not respond to conventional antibiotic therapy.

Protein S is protective in pulmonary fibrosis

Essentials Epithelial cell apoptosis is critical in the pathogenesis of idiopathic pulmonary fibrosis. Protein S, a circulating anticoagulant, inhibited apoptosis of lung epithelial cells. Overexpression of protein S in lung cells reduced bleomycin-induced pulmonary fibrosis. Intranasal therapy with exogenous protein S ameliorated bleomycin-induced pulmonary fibrosis. Background Pulmonary fibrosis is the terminal stage of interstitial lung diseases, some of them being incurable and of unknown etiology. Apoptosis plays a critical role in lung fibrogenesis. Protein S is a plasma anticoagulant with potent antiapoptotic activity. The role of protein S in pulmonary fibrosis is unknown. Objectives To evaluate the clinical relevance of protein S and its protective role in pulmonary fibrosis. Methods and Results The circulating level of protein S was measured in patients with pulmonary fibrosis and controls by the use of enzyme immunoassays. Pulmonary fibrosis was induced with bleomycin in transgenic mice overexpressing human protein S and wild-type mice, and exogenous protein S or vehicle was administered to wild-type mice; fibrosis was then compared in both models. Patients with pulmonary fibrosis had reduced circulating levels of protein S as compared with controls. Inflammatory changes, the levels of profibrotic cytokines, fibrosis score, hydroxyproline content in the lungs and oxygen desaturation were significantly reduced in protein S-transgenic mice as compared with wild-type mice. Wild-type mice treated with exogenous protein S showed significant decreases in the levels of inflammatory and profibrotic markers and fibrosis in the lungs as compared with untreated control mice. After bleomycin infusion, mice overexpressing human protein S showed significantly low caspase-3 activity, enhanced expression of antiapoptotic molecules and enhanced Akt and Axl kinase phosphorylation as compared with wild-type counterparts. Protein S also inhibited apoptosis of alveolar epithelial cells in vitro. Conclusions These observations suggest clinical relevance and a protective role of protein S in pulmonary fibrosis.

Efficient Inhibition of HIV Replication in the Gastrointestinal and Female Reproductive Tracts of Humanized BLT Mice by EFdA.

BackgroundThe nucleoside reverse transcriptase inhibitor (NRTI) 4'-ethynyl-2-fluoro-2'-deoxyadenosine (EFdA) in preclinical development exhibits improved safety and antiviral activity profiles with minimal drug resistance compared to approved NRTIs. However, the systemic antiviral efficacy of EFdA has not been fully evaluated. In this study, we utilized bone marrow/liver/thymus (BLT) humanized mice to investigate the systemic effect of EFdA treatment on HIV replication and CD4+ T cell depletion in the peripheral blood (PB) and tissues. In particular, we performed a comprehensive analysis of the female reproductive tract (FRT) and gastrointestinal (GI) tract, major sites of transmission, viral replication, and CD4+ T cell depletion and where some current antiretroviral drugs have a sub-optimal effect.ResultsEFdA treatment resulted in reduction of HIV-RNA in PB to undetectable levels in the majority of treated mice by 3 weeks post-treatment. HIV-RNA levels in cervicovaginal lavage of EFdA-treated BLT mice also declined to undetectable levels demonstrating strong penetration of EFdA into the FRT. Our results also demonstrate a strong systemic suppression of HIV replication in all tissues analyzed. In particular, we observed more than a 2-log difference in HIV-RNA levels in the GI tract and FRT of EFdA-treated BLT mice compared to untreated HIV-infected control mice. In addition, HIV-RNA was also significantly lower in the lymph nodes, liver, lung, spleen of EFdA-treated BLT mice compared to untreated HIV-infected control mice. Furthermore, EFdA treatment prevented the depletion of CD4+ T cells in the PB, mucosal tissues and lymphoid tissues.ConclusionOur findings indicate that EFdA is highly effective in controlling viral replication and preserving CD4+ T cells in particular with high efficiency in the GI and FRT tract. Thus, EFdA represents a strong potential candidate for further development as a part of antiretroviral therapy regimens.

Different immunological responses to early-life antibiotic exposure affecting autoimmune diabetes development in NOD mice

Environmental factors clearly influence the pathogenesis of Type 1 diabetes, an autoimmune disease. We have studied gut microbiota as important environmental agents that could affect the initiation or progression of type 1 diabetes especially in the prenatal period. We used neomycin, targeting mainly Gram negative or vancomycin, targeting mainly Gram positive bacteria, to treat pregnant NOD mothers and to study autoimmune diabetes development in their offspring. Neomycin-treated offspring were protected from diabetes, while vancomycin-treated offspring had accelerated diabetes development, and both antibiotics caused distinctly different shifts in gut microbiota composition compared with the offspring from untreated control mice. Our study demonstrated that neomycin treatment of pregnant mothers leads to generation of immune-tolerogenic antigen-presenting cells (APCs) in the offspring and these APCs had reduced specific autoantigen-presenting function both in vitro and in vivo. Moreover, the protection from diabetes mediated by tolerogenic APCs was vertically transmissible to the second generation. In contrast, more diabetogenic inflammatory T cells were found in the lymphoid organs of the offspring from the vancomycin-treated pregnant mothers. This change however was not transmitted to the second generation. Our results suggested that prenatal exposure to antibiotic influenced gut bacterial composition at the earliest time point in life and is critical for consequent education of the immune system. As different bacteria can induce different immune responses, understanding these differences and how to generate self-tolerogenic APCs could be important for developing new therapy for type 1 diabetes.

The Influence of Selenium Yeast on Hematological, Biochemical and Reproductive Hormone Level Changes in Kunming Mice Following Acute Exposure to Zearalenone

Healthy male Kunming mice received selenium yeast for 14days prior to a single oral administration of zearalenone (ZEN). After 48h, blood samples were collected for analysis and showed that mice in the ZEN-treated group has significantly decreased lymphocytes (P<0.05) and platelets (P<0.05) along with an increased white blood cell (WBC) count and other constituents (P<0.05). The serum biochemistry analysis of the ZEN group indicated that glutamic pyruvic transaminase (ALT), glutamic oxaloacetic transaminase (AST), urea, and uric acid were significantly increased (P<0.05), whilst total bilirubin (TB) and albumin (ALB) were decreased along with serum testosterone and estrogen (P<0. 05). The level of malondialdehyde (MDA) in the serum of the ZEN group was significantly increased whilst glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) had significantly decreased (P<0.05). Treatment with selenium yeast had a significant effect on response with most of the experimental parameters returning to levels similar to those observed in the untreated control mice. From these data, it can be concluded that ZEN is highly poisonous in Kunming mice with high levels of toxicity on the blood, liver, and kidneys. High levels of oxidative stress were observed in mice and pre-treatment with selenium yeast by oral gavage is effective in the ameliorated effects of ZEN-induced damage.

363. Improvement of Sandhoff Phenotype Following Intravenous Injection of Adeno-Associated Viral Vector Expressing a Hexosaminidase Isoenzyme in Adult Sandhoff Mice: Preclinical Safety and Efficacy Study

GM2 gangliosidosis disorders stem from a Hexosaminidase A (HexA) isoenzyme deficiency. In humans, HexA is the sole enzyme able to catabolize GM2 ganglioside (GM2). The inability to effectively catabolize GM2 leads to neurodegeneration of the central nervous system. HexA is comprised of 2 subunits (α, β) and works with the GM2 activator protein (GM2AP). In the recent work by Tropak et al. (Mol Ther Met Clin Dev, in press), a hybrid subunit, named µ-subunit, was created (patent pending) by combining the stabilization and GM2AP binding sites of the β-subunit while conserving the catalytic properties of the α-subunit. The ‘µ’-subunit, coded by HEXM, can homodimerize and form a stable, functional enzyme, named HexM, which can interact with GM2AP to hydrolyse GM2. Previous work for successful correction of Sandhoff mice using AAV was only shown in neonatal mice (with immature blood-brain barrier (BBB)) and may not directly help in designing a human clinical trial. In the current study, we examined the efficacy/safety of IV injections of the scAAV9/HEXM vector at two doses in adult SD mice (with mature BBB). In addition, we also tested if an adjunct IV injection of mannitol provides any enhancement in efficacy. At 6 weeks old, the vector was injected via tail vein in cohorts of n=17 and n=15 SD mice at 2.5E+12 or 1.0E+13 vg/mouse, respectively. Another cohort of 16 mice received IV mannitol (3g/kg) prior to an IV injection of 2.5E+12 vg scAAV9/HEXM. Some mice from low dose group were euthanized at 16 weeks for direct analysis with untreated SD control mice, while the remainder were left until for terminal survival. Analysis of survival benefit, locomotor behaviour, biochemical and molecular parameters were performed. While untreated SD mice had a 16 week humane endpoint, 4 of 7 mice in higher dose group are now surviving past 56 weeks, 1 of 12 mice in the low dose cohort, and 4 of 9 mice in the mannitol cohort are surviving past 52 weeks. These increases in survival are all highly significant compared to the ~16 week humane endpoint of untreated SD mice. Behaviourally, there are no major significant differences in locomotion between the groups until after 15 weeks, when the adjunct mannitol group significantly outperforms the PBS group. Survival and behaviour monitoring, and the biochemical analyses for this study are ongoing. The preliminary results from this study show delayed onset of the SD phenotype with a single AAV9/HEXM injection and a significant benefit of a pre-injection of IV mannitol. This study is the first to show that an IV gene transfer using a scAAV/HEXM vector can provide survival and behavioural benefit in adult SD mice especially with adjunct use of mannitol. We propose that these results can advise the design of a human gene therapy trial for SD and the related Tay-Sachs disease.

032 Suppressor of cytokine signaling 2 directs early tumor-immune escape of skin cancer

032 Suppressor of cytokine signaling 2 directs early tumor-immune escape of skin cancer

Toxicity of cuprizone a Cu2+ chelating agent on isolated mouse brain mitochondria: a justification for demyelination and subsequent behavioral dysfunction

Multiple Sclerosis (MS) is a complex disease with an unknown etiology and no effective cure, despite decades of extensive research that led to the development of several partially effective treatments. In this study we aimed to investigate brain mitochondrial dysfunction in demyelination induced by cuprizone in mice. Cuprizone was used for induction of demyelination in mice through a diet containing 0.2% w/w cuprizone for 5 weeks. Behavioral tests for proving of MS was performed and then mitochondria from brain of animals were isolated and afterwards parameters of mitochondrial dysfunction examined. Results of mitochondrial dysfunction parameters such as mitochondrial swelling, production ROS, collapse of the membrane potential showed that isolated mitochondria from cuprizone treated mice have been damaged compared to those of untreated control mice. It is likely that demyelination induced mitochondrial damage led to increased mitochondrial ROS formation and progression of oxidative damages in neurons. It is suggested that cuprizone which is a Cu2+ chelating agent causes impairment of electron transport chain (complex IV) and antioxidant system (SOD) in mitochondria leading to decreased ATP production and increased ROS formation.

Novel synergic antidiabetic effects of Astragalus polysaccharides combined with Crataegus flavonoids via improvement of islet function and liver metabolism.

The present study investigated the synergic effects and potential mechanisms of action of Astragalus polysaccharides (APS) combined with Crataegus flavonoids (CF) in the treatment of type1 diabetes. Diabetes was induced by intraperitoneal injection of 100mg/kg streptozotocin in mice. Normal and untreated diabetic control mice were used, and CF‑treated (200mg/kg/day), APS‑treated (200mg/kg/day), APS+CF (AC)‑treated (200mg/kg/day of each) and metformin‑treated (200mg/kg/day) diabetic mice were orally administrated the appropriate therapeutic agent for 4weeks. The results demonstrated that AC treatment significantly reduced the fasting blood glucose, food and water intake in the diabetic mice. The AC group demonstrated increased serum insulin levels and islet cell function was restored. Furthermore, the AC‑treated mice demonstrated significant increases in the protein expression levels of pancreatic and duodenal homeobox‑1 and phosphorylated adenosine 5'‑monophosphate‑activated protein kinase in the pancreatic and liver tissue samples, respectively. In addition, AC significantly increased the mRNA expression levels of neurogenin3, v‑mafmusculoaponeurotic fibrosarcoma oncogene family, proteinA and insulin, and simultaneously decreased the expressions of interleukin6, tumor necrosis factor‑α and chemokine (C‑C motif) ligand2 in the pancreatic islet cells of diabetic mice. The anti‑inflammatory activity of APS and the islet‑restoring effect of CF may contribute to the improvement of islet function. AC exerted greater antidiabetic effects compared with APS or CF treatments alone. These results indicated that AC treatment had a synergic antidiabetic effect, which may involve improvements in islet function and liver metabolism. These effects of AC may facilitate the treatment of type 1or2 diabetes, as these patients frequently experience impaired islet function and disordered extrapancreatic metabolism.

Ginseng Berry Extract Attenuates Dextran Sodium Sulfate-Induced Acute and Chronic Colitis.

This study investigates the in vivo functions of ginseng berry extract (GB) as a therapy for dextran sodium sulfate (DSS)-induced colitis. C57BL/6 mice were given drinking water containing DSS (3%) for eight days to induce acute colitis. At the same time, the mice received an oral dose of GB (50 mg/kg) once daily. The GB-treated mice were less susceptible to the development of acute colitis than were control mice treated with saline, as determined by weight loss, disease activity, and colon histology. The administration of GB to DSS-treated mice also reduced the numbers and inhibited the activation of colon-infiltrating T cells, neutrophils, intestinal CD103−CD11c+ dendritic cells (cDCs), and macrophages. In addition, GB treatment promoted the migration of CD103+CD11c+ cDCs and expansion of Foxp3+ regulatory T cells in the colons of DSS-treated mice. Similarly, in the DSS-induced chronic colitis model, GB treatment improved the macroscopic and histological appearance of the colon wall when compared to untreated control mice, as indicated by longer colon length and lower histological scores. This is the first report to show that oral administration of GB suppresses immune activation and protects against experimentally induced colitis.

A comparison of developmental and maternal toxicity of Perfluoro octane sulfonate (PFOS) in Mouse: Evaluation of histopathological and behavioral changes

Perfluorooctanesulfonate (PFOS) is a widely spread environmental contaminant. It accumulates in the brain and has potential neurotoxin effects. Due to chemical properties, PFOS shows persistency in the environment and therefore has potential hazardous effect. The risk of possible intra uterine exposure to PFOS poses a health concern for developmental effects. The goal of this study was survey of histological and behavioral changes made by PFOS in pregnant mice and their fetuses using common behavioral assays and HE then on the day 15, Behavioral experiments including (open field and passive avoidance) were used to assess toxic behavioral changes such as memory impairment and anxiety. After behavioral evaluations fetuses were dissected on day 15 of gestation and morphological and histological studies on pregnant mouse brain and her fetus were carried out using haematoxylin-eosin staining method. Our findings showed that PFOS can induce neurotoxicity in pregnant mouse especially by induction of abnormalities in dentate gyrus of hippocamps and disruption of neurobehavioral functions .Besides in her fetus; PFOS produced significant changes in brain, liver and thyroid gland in comparison with untreated control mouse fetus. As a conclusion, PFOS can cause both neurobehavioral and developmental toxicity in pregnant mouse and her fetus.

Landolphia owariensis leaf extracts reduce parasitemia in Plasmodium berghei-infected mice

Context Landolphia owariensis P. Beauv. (Apocyanaceae) leaf is used in southeast Nigeria to treat malaria.Objective This study evaluated the antiplasmodial activity of L. owariensis leaf extract and fractions, also the phytoconstituents were standardized and analyzed.Methods The effects of daily, oral administrations of 200, 400 and 800 mg/kg of L. owariensis leaf extract (LOE), its hexane (LOHF), ethyl acetate (LOEF) and methanol (LOMF) fractions on early, established and residual infections in Plasmodium berghei-infected albino mice were evaluated in vivo. The extract and fractions were subjected to phytochemical analysis and HPLC fingerprinting, and the acute toxicity of LOE was evaluated.Results The extract and fractions elicited 29–86, 18–95 and 75–96% significant (p < 0.001) suppression of parasitemia in early, established and residual infections, respectively. The ED50 values for suppressive activity of LOE, LOHF, LOEF and LOMF were 266.56, 514.93, 392.95 and 165.70 mg/kg, respectively. The post-day 30-survival index was 16.7–50, 16.7, 16.7–66.7 and 50–83.3% for LOE, LOHF, LOEF, and LOMF, respectively. Extract-treated mice significantly (p < 0.001) gained weight and had reduced mortality compared with negative control (untreated) mice. An oral LD50 value >5000 mg/kg in mice was established for LOE. The LOMF showed the greatest antiplasmodial activity in all the models, suggesting that the antimalarial activity of the plant may be attributed to alkaloids, flavonoids, saponins and tannins present in the fraction.Conclusion Results demonstrate the antiplasmodial activity of L. owariensis leaf, and provide a pharmacological rationale for its ethnomedicinal use as an antimalarial agent.

Prophylactic Use of Ganoderma lucidum Extract May Inhibit Mycobacterium tuberculosis Replication in a New Mouse Model of Spontaneous Latent Tuberculosis Infection.

A mouse model of spontaneous latent tuberculosis infection (LTBI) that mimics LTBI in humans is valuable for drug/vaccine development and the study of tuberculosis. However, most LTBI mouse models require interventions, and a spontaneous LTBI mouse model with a low bacterial load is difficult to establish. In this study, mice were IV-inoculated with 100 CFU Mycobacterium tuberculosis H37Rv, and a persistent LTBI was established with low bacterial loads (0.5~1.5log10 CFU in the lung; < 4log10 CFU in the spleen). Histopathological changes in the lung and spleen were mild during the first 20 weeks post-inoculation. The model was used to demonstrate the comparative effects of prophylactic and therapeutic administration of Ganoderma lucidum extract (spores and spores lipid) in preventing H37Rv replication in both lung and spleen. H37Rv was inhibited with prophylactic use of G. lucidum extract relative to that of the untreated control and therapy groups, and observed in the spleen and lung as early as post-inoculation week 3 and week 5 respectively. H37Rv infection in the therapy group was comparable to that of the untreated control mice. No significant mitigation of pathological changes was observed in either the prophylactic or therapeutic group. Our results suggest that this new LTBI mouse model is an efficient tool of testing anti-tuberculosis drug, the use of G. lucidum extract prior to M. tuberculosis infection may protect the host against bacterial replication to some extent.

Irregular External Gastric Stimulation is Associated with Suppression of Serum Ghrelin Levels and Prolonged Decrease in Weight: A Novel Method for Sustaining Weight Loss

Introduction: Weight regain is a major obstacle for most dietary procedures. Gastric stimulation has been shown to affect hormone levels. Aim: The aim of the present study was to determine the effect of irregular external gastric stimulation on longterm weight reduction. Methods: External gastric stimulation was performed by holding a rotator device on the abdomen of mice for 5 minutes in a regular or irregular manner. Mice were assessed for body weight and serum ghrelin levels. Results: External gastric stimulation was associated with a significant decrease in serum ghrelin levels. Irregular external gastric stimulation was associated with a prolonged effect on body weight reduction compared with regular stimulation. By the end of week 5, the body weight of untreated control mice had increased compared with a slight weight increase in mice treated with regular stimulation, while there was a significant continued decrease in the body weight of mice treated with irregular stimulation. Conclusions: Irregular gastric stimulation is associated with a prolonged effect on weight loss and provides a method for overcoming the brain-gut axis accommodation of weight loss.

Bortezomib-Induced Proinflammatory Macrophages Contribute to Multiple Myeloma Cell Aggressiveness

Multiple myeloma (MM) is a chronic progressive malignancy of plasma cells. Although treatment with the novel proteasome inhibitor, bortezomib, significantly improves patient survival, some patients fail to respond due to the development of de novo resistance. Previous studies revealed that chemotherapy induces pro-tumorigenic host-mediated effects which could explain tumor re-growth and metastasis(Gingis-Velitski, Loven et al. 2011, Katz, Shaked 2014). Here we show that plasma from bortezomib-treated mice significantly increases migration, viability and proliferation of human MM cells in vitro, compared to plasma from control untreated mice. Comparable results were demonstrated with plasma obtained from patients with MM treated with bortezomib. Additionally, bortezomib induces the mobilization of pro-angiogenic bone marrow cells. Mice treated with bortezomib and subsequently intravenously injected with MM cells succumb to MM aggressiveness earlier than mice treated with the vehicle control(Figure 1). We show that pro-inflammatory macrophages contribute to MM cell aggressiveness in response to bortezomib treatment, in part by secreting interleukin-16(IL-16). Blocking IL-16 in conditioned medium obtained from bortezomib-treated macrophages generated reduced viability of MM cells in vitro. Accordingly, co-inoculation of MM cells with pro-inflammatory macrophages from bortezomib-treated mice accelerates MM disease progression. Taken together, our results suggest that, in addition to the known effective anti-tumor activity of bortezomib, this drug can induce host-driven pro-tumorigenic effects that may promote MM aggressiveness. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Thrombopoietin-Mimetic Romiplostim Confers the Complete Survival Rate to Mice Exposed to Lethal Ionizing Radiation

Radiation-related casualties following exposure to a lethal dose of ionizing radiation show severe acute radiation syndromes (ARS) involving bone marrow death and gastrointestinal death. ARS cause decreases in red blood cell count, white blood cell count, platelet count and gastrointestinal dysfunction, finally leading to death caused by systemic bleeding. Therefore, reconstitution and restoration of hematopoiesis is a top priority. Although bone marrow transplantation (BMT) is also available for recovery from radiation-induced bone marrow damage, BMT for victims in radiation accidents has many limitations, including histocompatibility, age constraints, HLA type and the fact that immunosuppression would be required to reduce the risk of graft versus host rejection. In contrast, pharmacological approaches can accommodate a large number of victims with few limitations. Our previous study showed that the combined administration of erythropoietin, granulocytecolony stimulating factor and nandrolone decanoate after lethal ionizing irradiation resulted in the survival of approximately 50% of irradiated mice at day 30. When a c-Mpl agonist (Romiplostim: RP) was added to this protocol, 100% survival was obtained. Finally, we found that RP play a key role in the survival of irradiated mice. In the present study, we examined the effects of RP alone on mice exposed to lethal radiation.RP was administered at a dosage of 50 μg/kg of body weight/day to 8-weekold female C57BL/6JJcl mice for 1, 3, or 5 days immediately following exposure to a lethal 7 Gy dose of 137Cs γ-rays. The condition of each animal was analyzed via morphological evaluations of the small intestine and various parameters such as the numbers of peripheral blood cells, bone marrow cells, and hematopoietic progenitor cells along with cell surface antigen expression. By day 30, all untreated irradiated control mice died, whereas RP administration for 3 or 5 consecutive days after irradiation led to a 100% survival rate among the irradiated mice. At this time, the numbers of peripheral blood cells, bone marrow cells and hematopoietic progenitor cells were not significantly different between RP-untreated non-irradiated and RP-treated irradiated mice. In addition, the expression of macrophages, granulocytes and erythroid progenitors-related cell surface antigens on the bone marrow cells was significantly recovered in RP-treated irradiated mice compared to RP-untreated irradiated mice until day 20 after γ-irradiation. And, to estimate the effects of RP on gastrointestinal tissues in each individual, morphological evaluation H&E stain of the small intestine was performed until day 20 after γ-irradiation. As a result, RP promoted the recovery of gastrointestinal tissues damages in RP-treated irradiated mice compared to RP-untreated irradiated mice.Regarding cell death, radiation-induced gamma-H2AX expression in the nuclear of bone marrow cell was significantly decreased in RP-treated irradiated mice compared to RP-untreated irradiated mice immediately and after a period of 24 hours following a lethal 7 Gy dose of X-irradiation, indicating that the rate of apoptotic bone marrow cells was significantly decreased by RP-treatment. Meanwhile, 53BP1, which is well known as non-homologous end joining (NHEJ) factor, was significantly increased, showing that RP promoted NHEJ DNA repair in bone marrow cells treated with RP. These results demonstrate that c-Mpl agonist RP promotes the recovery of serious damages caused by lethal irradiation to the hematopoietic and gastrointestinal systems, and RP might be a useful radiomitigator in the case of ARS. DisclosuresNo relevant conflicts of interest to declare.

Prostaglandin E2 Signaling through EP4 Receptor Promotes Hematopoietic Stem Cell Niche Regeneration and Enhances Hematopoietic Recovery

High-dose radiation treatment for hematological malignancies such as leukemia, lymphoma or multiple myeloma induces damage to the bone marrow microenvironment that limits hematopoietic regeneration. We previously demonstrated that single administration of dimethyl prostaglandin E2 (dmPGE2) at 24 hrs post lethal irradiation (796 cGys; LD70/30) in mice increases survival and accelerates hematopoietic recovery. Since bone marrow niches regulate hematopoiesis, we investigated whether the effects of PGE2 administration on hematopoietic recovery and survival were dependent on PGE2 signaling in bone marrow stromal cells. Total body irradiation (TBI) severely disrupts bone marrow niche components including MSC, osteoblasts and endothelial cells. Multivariate flow cytometry revealed that exposure of mice to 650 cGy TBI reduced the total number of bone marrow MSC defined as CD45- Ter119- CD31- PDGFR+ CD51+ MSC by 8 fold and reduced functional fibroblast colony formation (CFU-F) by 8.5 fold. Osteoblast (OB) and endothelial cell (EC) counts were reduced by 6.5 fold and 6 fold respectively. Treatment of mice with dmPGE2 at 24 hours post-irradiation substantially rescued MSC and EC, which were 3.5 and 2.2-fold higher compared to un-treated irradiated mice. Histological and flow cytometric analysis indicated that total OB, OB precursors and mesenchymal progenitor cells (MPC) in bone marrow were also enhanced by PGE2 administration. Interestingly, dmPGE2 failed to rescue MSC and OB from aged (24-27 mo/old) mice compared to young (4-6 mo/old) mice. Since PGE2 signals through four receptors (EP1-4), each with unique signaling pathways, we hypothesized that the hematopoietic niche regeneration was due to activation of PGE2 signaling via one or more EP receptors. Treatment of mice with the EP4 receptor agonist L-902,688 following irradiation enhanced the recovery of bone marrow MSC by 3.1 fold and EC by 2.0 fold compared to untreated irradiated control mice. EP1, EP2 and EP3 receptor agonists failed to enhance hematopoietic niche regeneration in irradiated mice. To further investigate the role of EP4 signaling in bone marrow niche reconstruction and hematopoietic recovery, we transplanted BM cells from wild-type mice into syngeneic wild-type or conditional inducible EP4-/- recipients after lethal irradiation, and analyzed stromal cells recovery and hematopoietic reconstitution. At 15 days post-transplantation, chimeric mice with EP4-/- stroma displayed attenuated niche recovery and hematopoietic reconstitution compared to mice with wild-type stroma. PGE2 or EP4 agonist administration increased the expression of the endogenous anti-apoptotic protein Survivin, and enhanced survival of MSC and EC. In conclusion, our study suggests that PGE2 signaling through the EP4 receptor increases hemotopoietic recovery after TBI by enhancing the survival and expansion of MSC and endothelial cells. Furthermore, our data suggest the modulation/regulation PGE2 signaling in hematopoietic niche components could be beneficial to enhance HSC recovery following clinical hematopoietic transplantation. Disclosures No relevant conflicts of interest to declare.

Novel Patient Derived Multiple Myeloma Model Reflects Sensitivity Towards Anticancer Treatment in Multiple Myeloma Patients

Background Appropriate animal models for hematological malignancies are highly attractive, because they allow the study of the tumor biology and underlying disease mechanisms. They also constitute a major prerequisite for rapid bench-to-bedside translation of investigational anticancer therapies. To validate our multiple myeloma patient (pt)-derived xenograft (MM PDX) model (Schueler et al, Expert Opin Biol Ther, 2013), we systematically analyzed a panel of MM PDX with regard to their sensitivity towards standard of care treatment and compared these data with the pts' clinical outcome.Methods Bone marrow (BM) cells of 11 MM pts were implanted intratibialy (i.t.) into 103 NOD/Shi-scid/IL-2Rγnull (NOG) mice (n= 6-18 / pt sample). Mice were treated according to pts' therapy with VCD (Bortezomib, Cyclophosphamide, Dexamethasone), or to evaluate additional treatment options with Rd (Lenalidomide, Dexamethasone). Tumor growth and antitumoral activity in mice were assessed in tumor-bearing mice and compared to untreated control mice as well as to pts' response. Tumor growth in the mouse model was monitored by whole-body fluorescence-based in-vivo-imaging (IVI) using CF750-labeled α-HLA ABC antibody before and during treatment as well as 24h after last treatment cycle as described (Schueler J. PLOSone 2013). Mock-injected animals served as negative controls. Engraftment of human MM cells in murine organs was confirmed by flow cytometry and patho-histological analyses (immunostaining) at the end of the study.Results The pt cohort included a typical MM clientele for referral centers, with a median age of 75 years (range 56-85), median BM infiltration of 80% (20-90), and high- and standard-risk cytogenetics in 5 and 6 pts, respectively. All pts had advanced disease with Durie&Salmon stage III and active/symptomatic MM. All pts received VCD after diagnosis and BM sampling.MM cell engraftment could reliably be determined from experimental day 10 on in all 11 MM PDX models, at all assessed sites, namely within the BM, spleen and peripheral blood (PB) of recipient mice. Individual pt samples displayed distinct tumor growth patterns in vivo. Fluorescence intensity of engrafted murine organs ranged from 2- to 15-fold compared to mock injected control mice. Mean IVI signals in BM of recipient mice were 10-fold higher as compared to spleen signals, qualifying the BM niche as the preferred homing localization of pts' MM cells. Of note, both injected and non-injected BM sites were infiltrated by MM cells 10 days after tumor cell injection. Engraftment of human MM cells in the respective murine organs was confirmed by flow cytometry (HLA ABC, CD138, CD38) and histology and verified MM engraftment via both methods, confirming prior reports (Schüler PLOSone 2013; Groen Blood 2012;120:e9-16, Overdijk MAbs. 2015;7:311-21). The murine engraftment capacity was independent of MM type, disease stage, BM infiltration and cytogenetics of the donor pt.VCD was applied to 9 different MM PDX models and induced partial remission (PR; defined as at least 50% reduction of murine tumor load in BM, spleen and/or PB) in 5 out of 9 tested MM PDX models, whereas 2 cases each showed stable disease (SD) or progression (PD). The response rates in the mouse avatars mirrored the clinical outcome of the respective MM pts in 8/9 cases; only one MM pt showed serological and clinical PR, whereas the corresponding mice displayed SD. Rd induced PR in 1 and PD in a second MM PDX model, underlining the feasibility of MM PDX for drug screening approaches.Conclusions Due to the complex tumor biology, murine models of MM are still challenging. Our data support the preclinical rationale to use i.t.-injected NOG mice, since they closely resemble clinical MM with respect to symptoms, disseminated disease sites and response to anticancer treatment. Possible applications for the MM mouse avatars include development of new anticancer drugs as well as definition of biomarker strategies and selection of treatment options for individual pts with relapsed/refractory MM. The data of our preclinical study may serve as a useful future strategy to guide treatment decisions in refractory pts. The suitability as a drug development tool will be additionally determined performing treatment experiments with novel agents, e.g. elotuzumab or daratumumab. DisclosuresSchueler:Oncotest GmbH: Employment. Klingner:Oncotest GmbH: Employment.

Mitigative Effects of a Combination of Multiple Pharmaceutical Drugs on the Survival of Mice Exposed to Lethal Ionizing Radiation.

It is important to establish an easy-to-use therapeutic protocol for the emergency medical care of patients involved in radiation accidents to reduce the radiation-related casualties. The present study aimed to establish an optimum therapeutic protocol using currently approved pharmaceutical drugs to increase the survival of victims exposed to lethal radiation. Different combinations of four drugs-recombinant human erythropoietin (EPO), granulocyte-colony stimulating factor (G-CSF), c-mpl receptor agonist romiplostim (RP) and nandrolone decanoate (ND)-were administered to mice within 2 h after exposure to a lethal 7 Gy dose of γ-irradiation. On day 30 after irradiation, the condition of the mice was analyzed using various hematological parameters, such as the number of peripheral blood cells, bone marrow cells, hematopoietic progenitor cells and the expression of cell surface antigens. Approximately 10% of the untreated irradiated control mice survived for 21 days, but all of the control mice died by day 30. The combined administration of G-CSF, EPO and RP for five days immediately after irradiation led to a complete survival of the irradiated mice until day 30. However, the treatment with G-CSF, EPO and RP with ND led to only 75% survival at day 30. The hematological analyses showed that the numbers of almost all of hematopoietic cells in the surviving mice treated with effective medications recovered to the levels of non-irradiated mice. The present findings show that the combination of G-CSF, EPO and RP may be a useful countermeasure for victims exposed to accidental lethal irradiation.

BMET-14STAT3 INHIBITION ENHANCES THERAPEUTIC EFFICACY OF RADIATION TREATMENT AGAINST ESTABLISHED BRAIN METASTASIS IN MURINE MELANOMA MODEL

INTRODUCTION: Melanoma patients that develop brain metastasis have a median survival of 6 months. Radiation, a standard of care for local control of melanoma, has been reported to have immune stimulatory capacities. Therefore, we investigated the combinatorial effect of inhibitors of the signal transducer and activator of transcript 3 (STAT3) pathway, a potent mediator of immune suppression, and whole-brain radiation in a murine brain metastasis model. METHODS: C57BL/6 mice were intracerebrally implanted with B16 melanoma, irradiated with 7.5 Gy, and treated with an advanced lipid nanoparticle system that contained miR-124 (LNP-124) that inhibits the STAT3 pathway, or WP1066, a small molecule inhibitor of STAT3. Mice surviving 130+ days after tumor implantation were subcutaneously rechallenged with tumor. RESULTS: Monotherapy (LNP-124, WP1066, or radiation alone) demonstrated longer survival relative to untreated control mice; combination therapies further extended survival compared to single treatment agents. Median survival for mice receiving radiation combined with LNP124 or WP1066 was 65 days and 45.5 days, respectively, compared to 15 days for untreated mice and 19 - 40 days for monotherapy. While no untreated mice (control) survived over 20 days, the survival rate at day 130 for mice receiving combination therapy was almost 40%. Flow cytometry analysis showed higher IL-2 production in T cells from tumor-draining lymph nodes in mice treated with radiation plus STAT3 inhibitor. SUMMARY: These results indicate the combination of STAT3 inhibition and radiation enhances the therapeutic effect against established murine brain metastasis. The implications for this combination on antitumor immunity, immunologic memory and protection from recurrence will also be discussed.