Gamma Knockout Mice Research Articles

A Protease Activatable Interleukin-2 Fusion Protein Engenders Antitumor Immune Responses by Interferon Gamma-Dependent and Interferon Gamma-Independent Mechanisms.

Cytokines are powerful mediators of immune responses and some, such as interleukin-2 (IL-2), have achieved dramatic responses as cancer immunotherapies. Unfortunately, systemic administration often results in deleterious side effects, prompting exploration of strategies to localize cytokine activity to the tumor microenvironment (TME). To this end, we constructed an IL-2/IL2Ra fusion protein (IL-2FP) with an MMP2/9-specific cleavage site, designed to exploit the dysregulated protease activity in the TME to selectively activate IL-2 in the tumor. To determine if TME protease activity is sufficient to cleave the FP and if FP activity is due to specific cleavage, we created Colon 38 tumor cell lines expressing similar levels of IL-2FPs with either a functional cleavage site [H11(cs-1FP)] or a scrambled, noncleavable sequence [H2(scramFP)]. H11(cs-1FP) tumors demonstrated reduced tumor growth, characterized by regressions not observed in H2(scramFP) tumors. Analysis through qRT-PCR, flow cytometry, and immunohistochemistry indicate robust CD8 responses in the H11(cs-1FP) tumors. Interferon gamma (IFNg) knockout mice revealed that the immune effects of the cleavable FP are mediated through both IFNg-dependent and IFNg-independent mechanisms. Collectively, these data suggest that matrix metalloproteinases (MMPs) in the TME can cleave the IL-2FP specifically, thus enhancing an antitumor response, and provide a rationale for further developing this approach.

Warfarin Impairs the Bone Marrow Microenvironment and Hematopoiesis Via the Periostin/Integrin β3 Pathway

The coagulation system is a complex system comprised of various proteases and other factors which result in the formation of a blood clot, and proteases in general are known to regulate the mobilization of normal hematopoietic stem cells (HSC) from the bone marrow microenvironment (BMM). However, whether the proteases of the coagulation system are involved in the mobilization or maintenance of hematopoietic stem and progenitor cells (HSPC) is unknown.Hypothesizing that the proteases of the coagulation system play a role in the normal physiology of the BMM and that modulation of coagulation factors may have an effect on HSPC, we tested the effects of the anticoagulant warfarin, used in 1% of people worldwide for prophylactic or therapeutic anticoagulation. Indeed, treatment of wildtype mice with warfarin led to a decrease in myeloid cells in peripheral blood, decreased HSC function and mobilization from the BMM and an almost 8 fold reduction of functional HSC. Intrafemoral co-transplantation of warfarin-treated, ex-vivo expanded primary murine bone marrow stromal cells with untreated HSPC led to decreased engraftment of HSPC compared to co-transplantation of vehicle-treated stroma cells suggesting that warfarin may compromise bone marrow stroma. We have implicated periostin, a vitamin K dependent factor produced by bone marrow stroma - binding to integrin β3 and signaling via AKT in HSC - as being the cause of impairment of hematopoiesis during treatment with warfarin.In addition, warfarin treatment of NOD SCID interleukin-2 receptor gamma knockout (NSG) mice or intrafemoral cotransplantation of human warfarin-treated stroma cells and untreated human CD34+ HSC led to reduced engraftment of human CD45+ leukocytes. In corroboration of our murine data we showed that the total leukocyte and monocyte count, as well as the percentage of basophils and eosinophils were significantly reduced in 282 patients receiving warfarin and 89 patients receiving another vitamin K antagonist, fluindione, for anticoagulation compared to untreated healthy controls.In summary, warfarin or vitamin K antagonism treatment impairs HSC function in humans and mice via modification of the BMM and, specifically, by the impairment of the periostin/integrin β3 axis, which we, thereby, implicate also for the maintenance of normal HSC. [Display omitted] DisclosuresFontenay:Celgene: Research Funding.

The pathogenicity of two Neospora caninum goat strains in a BALB/c mouse model

Goats are frequently described as an intermediate host for the protozoan Neospora caninum, manifesting the disease mainly by recurrent abortions with placentitis and encephalitis in fetuses. Several reports of natural and experimental infections in cattle and mice show differences in the immune response, and the outcome of the infection can be variable depending on the species affected and by the behavior of the infective strain. This study describes for the first time two Neospora caninum strains isolated from naturally infected goats from the state of Minas Gerais, Brazil. One placenta and one brain from different goats were processed for a first bioassay in gerbils (Meriones unguiculatus). Subsequently, a second bioassay was performed by inoculating the processed brain samples from gerbils into Interferon gamma (IFN-γ) knockout mice (KO mice). Tachyzoites collected from the peritoneal fluid of the KO mice were inoculated into VERO cell monolayers, where they presented a very slow growth rate. The tachyzoites were also inoculated into BALB/c mice with a dose of 106 tachyzoites per animal. After a 5-week follow up, the animals infected with both of the strains developed a strong polarized Th1 response with increased serum and spleen gene expression levels of pro-inflammatory cytokines (mainly IFN-γ and TNF-α) in the first week. Tissue lesions were mild in the animals infected with both strains. Despite the strong immune response preventing an infection in the visceral organs, the parasite was able to reach the brain, causing progressive brain lesions from the second to fifth week post infection. The NC-goat1-infected mice presented with severe meningoencephalitis, but the NC-goat2-infected animals had considerable histological brain lesions only at week 5. Immunohistochemical analysis of the mouse brains revealed a different pattern of inflammatory cells compared to the naturally infected goats. A severe inflammatory infiltrate of CD3+ T lymphocytes was found in the NC-goat1-infected mice. A more discrete infiltrate of CD3+ T cells was found in the NC-goat2-infected animals. Additionally, IBA1 IHC revealed an intense microglial reaction and monocyte perivascular cuffs in the NC-goat1-infected animals and lower microglia/monocyte infiltrates in the NC-goat2-infected mice. This work contributes knowledge on the pathogenicity of new Neospora caninum strains in mice, comparable with other well-established mouse models of the disease, and demonstrates the importance of studying goats as an intermediate host of this parasite.

Abstract 3185: CAR-T cells can eradicate human uveal melanoma and immune-therapy resistant malignant melanoma in IL-2 transgenic NOD/SCID IL2 receptor gamma knockout mice

Abstract Immune therapies including checkpoint blockade and adoptive T cell transfer show great promise for the treatment of melanoma, with long-term effects in some patients. However, not all patients respond to current immune therapies and are in need of other treatment strategies. For example, around half of the patients with metastatic malignant melanoma will not be cured with available therapies today. For metastatic uveal melanoma (a rare melanoma of the eye) available immune therapies have less effect, and there is currently no approved therapy for these patients. Our objective is to find novel immune therapies with the potential to treat immune-therapy resistant melanoma, with the use of chimeric antigen receptor T cells (CAR-T). So far, no CAR-T therapy is approved for use in solid tumors. We have previously developed a humanized mouse model, where tumor cells and T cells from the same patient are grafted in IL-2 transgenic NOD/SCID IL2 receptor gamma knockout (NOG) mice, and found that responses in the mouse model correlated to responses in the corresponding patients in a clinical trial of adoptive T cell transfer (Jespersen et al, Nature Communications, 2017). In order to test the potential for CAR-T therapy in immune-therapy resistant melanoma in this mouse model, we used TCGA to determine the expression in melanoma biopsies of targets for commercially available CAR-T cells. Interestingly, we were able to use this model to treat immune-therapy resistant malignant melanoma and uveal melanoma patient-derived xenografts with human CAR-T cells and obtain curative responses, but only in IL-2 transgenic mice and not in regular NOG mice. These findings prove potential for the use of CAR-T cell therapy in immune-therapy resistant melanoma, and indicate the utility of this mouse model in the translation of CAR-T therapies. We are currently working on the development of CAR-T cells derived from patient-specific T cells. Citation Format: Elin Forsberg, Mattias Lindberg, Henrik Jespersen, Samuel Alsén, Roger Olofsson Bagge, Marco Donia, Inge Marie Svane, Ola Nilsson, Lars Ny, Lisa Nilsson, Jonas Nilsson. CAR-T cells can eradicate human uveal melanoma and immune-therapy resistant malignant melanoma in IL-2 transgenic NOD/SCID IL2 receptor gamma knockout mice [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3185.

The interleukin-4/PPARγ signaling axis promotes oligodendrocyte differentiation and remyelination after brain injury

The repair of white matter damage is of paramount importance for functional recovery after brain injuries. Here, we report that interleukin-4 (IL-4) promotes oligodendrocyte regeneration and remyelination. IL-4 receptor expression was detected in a variety of glial cells after ischemic brain injury, including oligodendrocyte lineage cells. IL-4 deficiency in knockout mice resulted in greater deterioration of white matter over 14 d after stroke. Consistent with these findings, intranasal delivery of IL-4 nanoparticles after stroke improved white matter integrity and attenuated long-term sensorimotor and cognitive deficits in wild-type mice, as revealed by histological immunostaining, electron microscopy, diffusion tensor imaging, and electrophysiology. The selective effect of IL-4 on remyelination was verified in an ex vivo organotypic model of demyelination. By leveraging primary oligodendrocyte progenitor cells (OPCs), microglia-depleted mice, and conditional OPC-specific peroxisome proliferator-activated receptor gamma (PPARγ) knockout mice, we discovered a direct salutary effect of IL-4 on oligodendrocyte differentiation that was mediated by the PPARγ axis. Our findings reveal a new regenerative role of IL-4 in the central nervous system (CNS), which lies beyond its known immunoregulatory functions on microglia/macrophages or peripheral lymphocytes. Therefore, intranasal IL-4 delivery may represent a novel therapeutic strategy to improve white matter integrity in stroke and other brain injuries.

The Vascular Bone Marrow Niche Influences Outcome in Chronic Myeloid Leukemia

The endosteal bone marrow niche is known to protect leukemic stem cells (LSC) from chemotherapy, but the role of the vascular niche in the bone marrow microenvironment in leukemia is largely unknown. E-selectin, which is expressed on bone marrow endothelial cells, has been described to regulate the dormancy of normal hematopoietic stem cells (HSC) by increasing HSC proliferation (Winkler IG, 2012). In chronic myeloid leukemia (CML), one of the myeloproliferative neoplasias caused by the oncogene BCR-ABL1, E-selectin (Krause DS, 2014) and the adhesion molecule CD44, which is overexpressed on CML-initiating cells (Krause DS, 2006) and to which E-selectin binds (Videira PA, 2018), was shown to be essential for homing and engraftment of LSC. However, exact mechanisms of the interactions between BCR-ABL1, CD44 expression and interactions with the vascular niche are unclear.Hypothesizing that E-selectin influences the cell cycle of leukemic stem cells (LSC) in CML leading to improved eradication of LSC in case of treatment with the tyrosine kinase inhibitor imatinib, we treated murine recipients of CML-initiating cells in the retroviral transduction/transplantation model with the E -selectin inhibitor GMI-1271 (uproleselan, GlycoMimetics, Inc.) and imatinib, considered standard of care in CML. This increased the survival of mice compared to animals treated with imatinib alone and decreased the engraftment of CML-initiating cells in this model, as well as in the majority of mice in a xenotransplantation model of NOD SCID IL2 receptor gamma knockout (NSG) mice injected with human CML cells and treated with uproleselan. Treatment of NSG mice with uproleselan also decreased the contact time of injected human CML cells with the bone marrow endothelium. As shown in in vitro and in vivo experiments treatment with GMI-1271 and non-adhesion to E-selectin increased the cell cycle of BCR-ABL1+ LSC with a concomitant increase in expression of the transcriptional regulator and protooncogene Scl/Tal1. SCL/TAL1 was shown to negatively regulate CD44 expression by binding to the CD44 regulatory element, which was increased in presence of imatinib. In addition, we demonstrated SCL/TAL1 to be an indirect phosphorylation target of BCR-ABL1 and a negative transcriptional regulator of CD44 expression.In confirmation of our findings in mice, we also showed a negative correlation between SCL/TAL1 and CD44 expression in leukocytes of human patients with CML and that increased SCL/TAL1 expression is associated with decreased probability of relapse and increased relapse-free survival in human CML patients after allogeneic hematopoietic stem cell transplantation.In summary, inhibition of E-selectin in murine CML may lead to ‘non-adherence’ of LSC to the vascular niche and improved eradication by imatinib. This is likely due to an increase in cell cycle and an increase of Scl/Tal1 expression, which is shown to be regulated by BCR-ABL1. These data connect the adhesion of LSC in CML to the vascular niche via CD44 with the regulation of CD44 expression by SCL/TAL1 and BCR-ABL1, offering a potential new avenue for treatment. DisclosuresKrause:Glycotope: Consultancy; Glycomimetics Inc. until 06/2016: Consultancy, Research Funding; Merck KgGA in future: Research Funding; European Patent: Patents & Royalties: European Patent No. 16187926.7-1401 “FIBRONECTIN FOR USE IN THE TREATMENT OF LEUKEMIA” .

Microsatellite pattern analysis of Neospora caninum from a naturally infected goat fetus

Neospora caninum is an apicomplexan protozoan responsible for abortion in ruminants. The present study aimed to diagnose an abortion from an Anglo Nubian goat from a dairy herd located in Buenos Aires province, Argentina. The goat delivered a fetus of approximately 3 months gestation that was studied by indirect fluorescent antibody test (IFAT), Immunoblot (IB), histopathology (HP), immunohistochemistry (IHC), and molecular assays (PCR, sequencing and microsatellite genotyping). Interferon gamma knock-out mice were inoculated with a pool of tissues for isolation attempts. The mother had IFAT titers of 1:3200 and 1:400 for N. caninum and Toxoplasma gondii, respectively, as well as positive IB reactions, whereas the fetus was seronegative to both parasites by IFAT and IB. The fetus had severe multifocal necrotizing myocarditis and hepatitis, moderate interstitial pneumonia, and nephritis. Myocardium sample resulted positive by IHC, evidencing clusters of N. caninum tachyzoites within myocardiocytes associated with histopathological lesions. Neospora caninum-DNA was detected by PCR in heart, liver, lungs, kidney, and muscle from the fetus, and was negative for T. gondii by PCR. NC-5 and 18 S rRNA gene fragment sequences showed 100% identity with N. caninum. Inoculated mice bled 30 days post-inoculation resulted seronegative to N. caninum and T. gondii by IFAT, and showed no clinical signs. Multilocus-microsatellite genotyping revealed a genetic profile that differed from previously reported N. caninum genotypes, with unique MS21 and MS10 alleles. These findings indicate that N. caninum was efficiently transmitted from the mother to the fetus. We report the first case of direct detection of N. caninum in a goat fetus in Argentina and N. caninum microsatellite genotyping in naturally infected goat.

Sarcocystis pantherophisi n. sp., from Eastern Rat Snakes (Pantherophis alleghaniensis) as Definitive Hosts and Interferon Gamma Gene Knockout Mice as Experimental Intermediate Hosts.

Here, we report a new species, Sarcocystis pantherophisi n. sp., with the Eastern rat snake (Pantherophis alleghaniensis) as natural definitive host and the interferon gamma gene knockout (KO) mouse as the experimental intermediate host. Sporocysts (n = 15) from intestinal contents of the snake were 10.8 × 8.9 μm. Sporocysts were orally infective to KO mice but not to laboratory-raised albino outbred house mice (Mus musculus). The interferon gamma KO mice developed schizont-associated neurological signs, and schizonts were cultivated in vitro from the brain. Mature sarcocysts were found in skeletal muscles of KO mice examined 41 days postinoculation (PI). Sarcocysts were slender, up to 70 μm wide and up to 3.5 mm long. By light microscopy, sarcocysts appeared thin-walled (<1 μm) without projections. By transmission electron microscopy, the sarcocyst wall was a variant of "type 1" (type 1i, new designation). The parasitophorous vacuolar membrane (pvm) had approximately 100-nm-wide × 100-nm-long bleb-like evaginations interspersed with 100-nm-wide × 650-nm-long elongated protrusions at irregular distances, and invaginations into the ground substance layer (gs) for a very short distance (6 nm). The gs was smooth, up to 500 nm thick, without tubules, and contained a few vesicles. Longitudinally cut bradyzoites at 54 days PI were banana-shaped, 7.8 × 2.2 μm (n = 5). Molecular characterization using 18S rRNA, 28S rRNA, ITS-1, and cox1 genes indicated a close relationship with other Sarcocystis parasites that have snake-rodent life cycles. The parasite in the present study was molecularly and biologically similar to a previously reported isolate (designated earlier as Sarcocystis sp. ex Pantherophis alleghaniensis) from P. alleghaniensis, and it was structurally different from other Sarcocystis species so far described.

CAMK2γ in intestinal epithelial cells modulates colitis-associated colorectal carcinogenesis via enhancing STAT3 activation.

Inflammation is one of the major risk factors for cancer. Here, we show that calcium/calmodulin-dependent protein kinase II gamma (CAMK2γ) in intestinal epithelial cells (IECs) modulates inflammatory signals and promotes colitis-associated cancer (CAC) in mice. We have identified CAMK2γ as a downstream target of colitis-induced WNT5a signaling. Furthermore, we have shown that CAMK2γ protects against intestine tissue injury by increasing IEC survival and proliferation. CAMK2γ knockout mice displayed reduced CAC. Furthermore, we used bone marrow transplantation to reveal that CAMK2γ in IECs, but not immune cells, was crucial for its effect on CAC. Consistently, transgenic over-expression of CAMK2γ in IECs accelerated CAC development. Mechanistically, CAMK2γ in IECs enhanced epithelial STAT3 activation to promote survival and proliferation of colonic epithelial cells during CAC development. These results thus identify a new molecular mechanism mediated by CAMK2γ in IECs during CAC development, thereby providing a potential new therapeutic target for CAC.

Establishment and characterization of a new human myxoid liposarcoma cell line (DL-221) with the FUS-DDIT3 translocation

Myxoid liposarcoma has the pathognomonic fusion oncogene FUS-DDIT3 encoding a chimeric transcription factor. Metastatic risk is higher with an increased round cell component and has been linked to aberrations involving the IGFR/PI3K/AKT pathway. These molecular insights have yet to translate to targeted therapies, and the lack of experimental models is a major hindrance. We describe the initial in-depth characterization of a new cell line (DL-221) and establishment of a mouse xenograft model. The cell line DL-221 was derived from a metastatic pleural lesion showing myxoid and round cell histology. This newly established cell line was characterized for phenotypic properties and molecular cytogenetic profile, using PCR, COBRA-FISH, and western blot. Next-generation whole-exome sequencing was performed to further characterize the cell line and the parent tumor. NOD-SCID-IL2R gamma knockout mice were xenograft hosts. DL-221 cells grew an adhering monolayer and COBRA-FISH showed an aneuploid karyotype with t(12;16)(q13;p11) and several other rearrangements; RT-PCR demonstrated a FUS-DDIT3 fusion transcript type 1. Both the cell line and the original tumor harbored a TP53 compound heterozygous mutation in exon 4 and 7, and were wild-type for PIK3CA. Moreover, among the 1254 variants called by whole-exome sequencing, there was 77% concordance between the cell line and parent tumor. The recently described hotspot mutation in the TERT promoter region in myxoid liposarcomas was also found at C228T in DL-221. Xenografts suitable for additional preclinical studies were successfully established in mice after subcutaneous injection. The established DL-221 cell line is the only published available myxoid liposarcoma cell line that underwent spontaneous immortalization, without requiring SV40 transformation. The cell line and its xenograft model are unique and helpful tools to study the biology and novel potential-targeted treatment approaches for myxoid liposarcoma.

Proinflammatory M1 Macrophages Inhibit RANKL-Induced Osteoclastogenesis.

In response to a defined panel of stimuli, immature macrophages can be classified into two major phenotypes: proinflammatory (M1) and anti-inflammatory (M2). Although both phenotypes have been implicated in several chronic inflammatory diseases, their direct role in bone resorption remains unclear. The present study investigated the possible effects of M1 and M2 macrophages on RANKL-induced osteoclastogenesis. In osteoclastogenesis assays using RAW264.7 cells or bone marrow cells as osteoclast precursors, addition of M1 macrophages significantly suppressed RANKL-induced osteoclastogenesis compared to nonstimulated conditions (M0), addition of M2 macrophages, or no macrophage addition (P < 0.05), suggesting that M1 macrophages can downregulate osteoclastogenesis. This effect was maintained when direct contact between M1 and osteoclast precursors was interrupted by cell culture insertion, indicating engagement of soluble factors released from M1. M1 macrophages developed from interferon gamma (IFN-γ) knockout (IFN-γ-KO) mice lost the ability to downregulate osteoclastogenesis. Antibody-based neutralization of interleukin-12 (IL-12), but not IL-10, produced by M1 macrophages also abrogated M1-mediated downregulation of osteoclastogenesis. Real-time PCR analyses showed that IFN-γ suppressed gene expression of NFATc1, a master regulator of osteoclastogenesis, whereas IL-12 increased the apoptosis of osteoclasts, suggesting molecular mechanisms underlying the possible roles of IFN-γ or IL-12 in M1-mediated inhibition of osteoclastogenesis. These findings were confirmed in an in vivo ligature-induced mouse periodontitis model in which adoptive transfer of M1 macrophages showed a significantly lower level of bone loss and less tartrate-resistant acid phosphatase (TRAP)-positive cell induction than M0 or M2 macrophage transfer. In conclusion, by its secretion of IFN-γ and IL-12, M1, but not M0 or M2, was demonstrated to inhibit osteoclastogenesis.

Epineurial adipocytes are dispensable for Schwann cell myelination

Previous clinical observations and data from mouse models with defects in lipid metabolism suggested that epineurial adipocytes may play a role in peripheral nervous system myelination. We have used adipocyte-specific Lpin1 knockout mice to characterize the consequences of the presence of impaired epineurial adipocytes on the myelinating peripheral nerve. Our data revealed that the capacity of Schwann cells to establish myelin, and the functional properties of peripheral nerves, were not affected by compromised epineurial adipocytes in adipocyte-specific Lpin1 knockout mice. To evaluate the possibility that Lpin1-negative adipocytes are still able to support endoneurial Schwann cells, we also characterized sciatic nerves from mice carrying epiblast-specific deletion of peroxisome proliferator-activated receptor gamma, which develop general lipoatrophy. Interestingly, even the complete loss of adipocytes in the epineurium of peroxisome proliferator-activated receptor gamma knockout mice did not lead to detectable defects in Schwann cell myelination. However, probably as a consequence of their hyperglycemia, these mice have reduced nerve conduction velocity, thus mimicking the phenotype observed under diabetic condition. Together, our data indicate that while adipocytes, as regulators of lipid and glucose homeostasis, play a role in nerve function, their presence in epineurium is not essential for establishment or maintenance of proper myelin.

Abstract 364: Nrf2-PPAR gamma Signaling Suppresses Exaggerated Renal Tubular AT1R Gene Expression and Function and Mitigates Hypertension During Oxidative Stress

Oxidative stress plays an important role in the development of hypertension. Interestingly, angiotensin type 1 receptor (AT1R) function, a major contributor to the etiology of hypertension, is positively regulated by oxidative stress. It is shown that antioxidant treatment can reduce blood pressure (BP) and redox-sensitive transcription factor Nrf2 could provide important clues for antihypertensive properties of antioxidants. Here in we investigated how induction of renal proximal tubular Nrf2 in response to antioxidants will activate PPAR gamma (a pleiotropic nuclear receptor whose ligands exhibit BP reducing effects) which in turn will normalize AT1R expression and reduce BP. Wild type (WT) and renal proximal tubular specific Nrf2 knockout (KO) mice were treated with 10 mM L-buthionine-sulfoximine (BSO, a pro-oxidant) without and with sulforaphane (S, an antioxidant; 5 μM daily by gavage) for 5 wks. BSO-treatment increased oxidative stress, AT1R mRNA, AT1R expression and Ang II-induced activation of renal sodium transporters and these animals exhibited high BP (mm Hg, WT: 102±3, WT-BSO: 123±4, Nrf2 KO: 98±2). However, the onset and severity of hypertension (Nrf2-KO-BSO: 136±4) as well as oxidative stress and AT1R function was more robust in BSO-treated Nrf2 KO compared to WT mice. More importantly, sulforaphane activated Nrf2, reduced oxidative stress, normalized proximal tubular AT1R function and reduced BP (WT-S: 99±5, WT-BSO+S: 106±6) in BSO-treated WT mice but failed to mitigate AT1R function or reduce BP (Nrf2 KO-S: 97±4, Nrf2 KO-BSO+S: 130±3) in Nrf2 KO mice. Further studies showed that BSO-induced hypertension is also more severe in renal proximal tubular specific PPAR gamma KO mice and sulforaphane fails to protect PPAR gamma KO mice from hypertension. Experiments in human renal proximal tubular cells indicated that 1) sulforaphane, via Nrf2 activation, reduced oxidant-induced AT1R upregulation and 2) Nrf2 dependent PPAR gamma activation suppresses AT1R gene transcription. These findings suggest that antioxidants via Nrf2 activation reduce oxidative stress, normalize AT1R signaling and prevent hypertension during oxidative stress. More importantly, Nrf2 induction activates PPAR gamma which suppresses AT1R gene transcription.

Kinetic analysis of cytokines, chemokines, chemokine receptors and adhesion molecules in murine ocular toxoplasmosis

Background/AimsTo investigate the molecules possibly influencing the recruitment and migration of leucocytes in murine ocular toxoplasmosis, the kinetics of the messenger RNA expression levels of cytokines, chemokines, chemokine receptors and...

Abstract 5241: Development of a single Listeria monocytogene-based vaccine simultaneously targeting two antigens

Abstract Previously published studies reported that recombinant Listeria monocytogenes (Lm-LLO)-based vaccines expressing either tumor associated antigens (TAA) or angiogenesis associated antigens fused to an immunogenic fragment of listeriolysin O (LLO) have demonstrated efficacy in mouse models with several types of tumors such as lung, breast, prostate or melanoma. Therefore, we hypothesized that an Lm-LLO vaccine capable of delivering two disparate antigens with two different therapeutic mechanisms would likely have a synergistic effect on decreasing tumor growth by 1) targeting blood vessels, which may enhance effector T cell infiltration into the tumor and 2) improving the therapeutic efficacy of the vaccine. In addition, a dual vaccine construct creates a flexible platform for future use. The Lm-LLO-cHER2 vaccine was developed using a chimeric HER2/neu (cHER2) construct, and was found to regress tumors, elicit a strong T cell immune response and break immune tolerance towards the HER2/neu self-antigen in experimental animals. The Lm-LLO-VEGR2 vaccine has been shown to eradicate established breast tumors, reduce microvascular density, protect against tumor rechallange and metastases, and induce epitope spreading to various regions of the TAA such as HER2/neu. A dual Lm-LLO vaccine was developed that expresses and secretes both the VEGFR2 and cHER2 antigens as LLO-based proteins and is based on a highly attenuated Listeria monocytogenes backbone Lm Δ dal dat actA, which is cleared 48 hours post-injection in interferon gamma knock-out mice. Initial characterization of the dual vaccine indicates that the two antigens cHER2 and VEGFR2 are stably expressed and secreted after two in vivo mouse passages. Currently, we are evaluating the anti-tumor effects and antigen specific immune responses generated by the dual vaccine in mouse models. If successful, this dual vaccine may offer a new immunotherapy for the treatment of cancer in humans. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5241. doi:1538-7445.AM2012-5241

Host mouse strain is not selective for a laboratory adapted strain of Schistosoma mansoni.

We genotyped pooled adult worms of Schistosoma mansoni from infected CF1, C57BL/6, BALB/c, and BALB/c interferon gamma knockout mice in order to establish if mouse strain differences selected for parasite genotypes. We also compared differentiation in eggs collected from liver and intestines to determine if there was differential distribution of parasite strains in the vertebrate host that might account for any genotype selection. We found that mouse strains with differing immune responses did not differ in resistance to infection and did not select for parasite genotypes. Schistosoma mansoni egg allele frequencies were also equally distributed in tissues and the difference between adult and egg allele frequencies was negligible.

Leishmania spp. parasite isolation through inoculation of patient biopsy macerates in interferon gamma knockout mice

Isolation of Leishmania parasite and species identification are important for confirmation and to help define the epidemiology of the leishmaniasis. Mice are often used to isolate pathogens, but the most common mouse strains are resistant to infection with parasites from the Leishmania (Viannia) subgenus. In this study we tested the inoculation of interferon gamma knockout (IFNgamma KO) mice with biopsy macerates from Leishmania-infected patients to increase the possibility of isolating parasites. Biopsies from twenty five patients with clinical signs of leishmaniasis were taken and tested for the presence of parasites. Immunohistochemical assay (IHC) and conventional histopathology detected the parasite in 88% and 83% of the patients, respectively. Leishmania sp. were isolated in biopsy macerates from 52% of the patients by culture in Grace's insect medium, but 13% of isolates were lost due to contamination. Inoculation of macerates in IFNgamma KO mice provides isolation of parasites in 31.8% of the biopsies. Most isolates belong to L. (Viannia) subgenus, as confirmed by PCR, except one that belongs to L. (Leishmania) subgenus. Our preliminary results support the use of IFNgamma KO mice to improve the possibility to isolate New World Leishmania species.

DNA vaccination with T‐cell epitopes encoded within Ab molecules induces high‐avidity anti‐tumor CD8+ T cells

Stimulation of high-avidity CTL responses is essential for effective anti-tumor and anti-viral vaccines. In this study we have demonstrated that a DNA vaccine incorporating CTL epitopes within an Ab molecule results in high-avidity T-cell responses to both foreign and self epitopes. The avidity and frequency was superior to peptide, peptide-pulsed DC vaccines or a DNA vaccine incorporating the epitope within the native Ag. The DNA Ab vaccine was superior to an identical protein vaccine that can only cross-present, indicating a role for direct presentation by the DNA vaccine. However, the avidity of CTL responses was significantly reduced in Fc receptor gamma knockout mice or if the Fc region was removed suggesting that cross presentation of Ag via Fc receptor was also important in the induction of high-avidity CTL. These results suggest that generation of high-avidity CTL responses by the DNA vaccine is related to its ability to both directly present and cross-present the epitope. High-avidity responses were capable of efficient anti-tumor activity in vitro and in vivo. This study demonstrates a vaccine strategy to generate high-avidity CTL responses that can be used in anti-tumor and anti-viral vaccine settings.

Characterization of Antiestrogenic Activity of the Chinese Herb,Prunella vulgaris, Using In Vitro and In Vivo (Mouse Xenograft) Models1

Prunella vulgaris (PV), a commonly used Chinese herb, also known as Self-heal, has a wide range of reported medicinal activities. By screening multiple herbs using the endometrial cancer cell line, ECC-1, and an alkaline phosphatase detection assay, we found that PV displayed significant antiestrogenic activity. We investigated the possible usefulness of antiestrogenic activity using both in vitro and in vivo models of endometrial function. Using the well-differentiated, hormone-responsive endometrial cell line, ECC-1, PV extract, at concentrations that were not toxic to the cells, significantly reduced alkaline phosphatase activity and cell proliferation in response to estrogen in a dose-dependent manner. The expression of CYR61, an estrogen-induced protein, was blocked in ECC-1 cells by both the antiestrogen ICI 182,780 and PV extract. Interestingly, PV extract did not appear to directly inhibit estrogen signaling. Rather, we found that its activities were probably related to an ability to function as an aryl hydrocarbon receptor (AHR) agonist in ECC-1 cells. In support of this hypothesis, we noted that PV induced CYP1A1, CYP1B1, and AHR repressor expression in a dose-dependent manner--responses that were blocked by small interfering RNA treatment to reduce AHR and specific AHR antagonists. Ovariectomized immunodeficient RAG-2/gamma(c) knockout mice implanted with human endometrial xenografts developed implants only when treated with estrogen. Mice treated with estrogen and PV tea in their drinking water had fewer and smaller xenograft implants compared with their estrogen-treated counterparts that drank only water (P < 0.05). Analysis of the resulting implants by immunohistochemistry demonstrated persistent estrogen receptor (ER), but reduced proliferation and CYR61 expression. Mouse uterine tissue weight in PV-treated mice was not different from controls, and cycle fecundity of intact C57 female mice was unaffected by PV tea treatment. PV, or Self-heal, exhibits significant antiestrogenic properties, both in vitro and in vivo. This activity is likely due to the ability of PV-activated AHR to interfere with estrogen. This herb may be useful as an adjunct for the treatment of estrogen-dependent processes like endometriosis and breast and uterine cancers. Full characterization of this herb will likely provide new insights into the crosstalk between AHR and ESR1, with potential for therapeutic applications in women.

A Role for IFN-γ from Antigen-Specific CD8+ T Cells in Protective Immunity toListeria monocytogenes

Whether IFN-gamma contributes to the per-cell protective capacity of memory CD8(+) T cells against Listeria monocytogenes (LM) has not been formally tested. In this study, we generated LM Ag-specific memory CD8(+) T cells via immunization of wild-type (WT) and IFN-gamma-deficient (gamma knockout (GKO)) mice with LM peptide-coated dendritic cells and compared them phenotypically and functionally. Immunization of WT and GKO mice resulted in memory CD8(+) T cells that were similar in number, functional avidity, TCR repertoire use, and memory phenotype. The protective capacity of memory CD8(+) T cells from immunized WT and GKO mice was evaluated after adoptive transfer of equal numbers of WT or GKO cells into naive BALB/c mice followed by LM challenge. The adoptively transferred CD8(+) T cells from GKO donors exhibited a decreased ability to reduce bacterial numbers in the organs of recipient mice when compared with an equivalent number of Ag-matched WT CD8(+) T cells. This deficiency was most evident early (day 3) after infection if a relatively low infectious dose was used; however, transferring fewer memory CD8(+) T cells or increasing the LM challenge dose revealed a more pronounced defect in protective immunity mediated by the CD8(+) T cells from GKO mice. Our studies identified a decrease in Ag-specific target cell lysis in vivo by CD8(+) T cells from GKO mice as the mechanism for the decreased protective immunity after LM challenge. Further studies suggest that the lack of IFN-gamma production by the Ag-specific CD8 T cells themselves diminishes target cell sensitivity to cytolysis, thereby reducing the lytic potency of IFN-gamma-deficient LM-specific memory CD8(+) T cells.