PBS-treated Mice Research Articles

IFNγ-Stimulated B Cells Inhibit T Follicular Helper Cells and Protect Against Atherosclerosis.

B and T cells are interconnected in the T follicular helper—germinal center B cell (TFH-GC B cell) axis, which is hyperactive during atherosclerosis development and loss of control along this axis results in exacerbated atherosclerosis. Inhibition of the TFH–GC B cell axis can be achieved by providing negative co-stimulation to TFH cells through the PD-1/PD-L1 pathway. Therefore, we investigated a novel therapeutic strategy using PD-L1-expressing B cells to inhibit atherosclerosis. We found that IFNγ-stimulated B cells significantly enhanced PD-L1 expression and limited TFH cell development. To determine whether IFNγ-B cells can reduce collar-induced atherosclerosis, apoE−/− mice fed a Western-type diet were treated with PBS, B cells or IFNγ-B cells for a total of 5 weeks following collar placement. IFNγ-B cells significantly increased PD-L1hi GC B cells and reduced plasmablasts. Interestingly, IFNγ-B cells–treated mice show increased atheroprotective Tregs and T cell-derived IL-10. In line with these findings, we observed a significant reduction in total lesion volume in carotid arteries of IFNγ-B cells-treated mice compared to PBS-treated mice and a similar trend was observed compared to B cell-treated mice. In conclusion, our data show that IFNγ-stimulated B cells strongly upregulate PD-L1, inhibit TFH cell responses and protect against atherosclerosis.

Suppression of lipopolysaccharide-induced corneal opacity by hepatocyte growth factor

Keratitis induced by bacterial toxins, including lipopolysaccharide (LPS), is a major cause of corneal opacity and vision loss. Our previous study demonstrates hepatocyte growth factor (HGF) promotes epithelial wound healing following mechanical corneal injury. Here, we investigated whether HGF has the capacity to suppress infectious inflammatory corneal opacity using a new model of LPS-induced keratitis. Keratitis, induced by two intrastromal injections of LPS on day 1 and 4 in C57BL/6 mice, resulted in significant corneal opacity for up to day 10. Following keratitis induction, corneas were topically treated with 0.1% HGF or PBS thrice daily for 5 days. HGF-treated mice showed a significantly smaller area of corneal opacity compared to PBS-treated mice, thus improving corneal transparency. Moreover, HGF treatment resulted in suppression of α-SMA expression, compared to PBS treatment. HGF-treated corneas showed normalized corneal structure and reduced expression of pro-inflammatory cytokine, demonstrating that HGF restores corneal architecture and immune quiescence in corneas with LPS-induced keratitis. These findings offer novel insight into the potential application of HGF-based therapies for the prevention and treatment of infection-induced corneal opacity.

NR4A1 agonist cytosporone B attenuates neuroinflammation in a mouse model of multiple sclerosis.

Nuclear receptor subfamily 4 group A1 (NR4A1) is an orphan nuclear receptor, which is expressed in the majority of cells. NR4A1 expression in peripheral blood mononuclear cells is low during the preclinical stage of multiple sclerosis. Knockout of the Nr4a1 gene in mice can aggravate the symptoms of experimental autoimmune encephalomyelitis (EAE), which is an animal model of multiple sclerosis. In this study, we intragastrically administered the NR4A1 agonist cytosporone B (Csn-B) to mice after inducing EAE. After treatment with Csn-B, the clinical symptoms in the EAE mice were substantially attenuated compared with that in PBS-treated control mice. The percentages of CD4+ T cells and F4/80+ cells in the central nervous system were decreased. In addition, interferon-γ and interleukin-17 production by proinflammatory Th1/Th17 cells in the central nervous system and interferon-γ levels in splenocytes were decreased after Csn-B treatment. These findings suggest that the NR4A1 agonist Csn-B can alleviate nerve injury after EAE induction, and, therefore, may be useful as a potential treatment for multiple sclerosis.

Exosomes Secreted by Umbilical Cord Blood-Derived Mesenchymal Stem Cell Attenuate Diabetes in Mice.

Mesenchymal stem cell (MSC) therapy is an innovative approach in diabetes due to its capacity to modulate tissue microenvironment and regeneration of glucose-responsive insulin-producing cells. In this study, we investigated the role of MSC-derived exosomes in pancreatic regeneration and insulin secretion in mice with streptozotocin-induced diabetes. Mesenchymal stem cells (MSCs) were isolated and characterized from umbilical cord blood (UCB). Exosomes were isolated and characterized from these MSCs. Diabetes was induced in male C57Bl/6 mice by streptozotocin (STZ; 40 mg/kg body weight, i.p.) for five consecutive days. The diabetic mice were administered (i.v.) with MSC (1 × 105 umbilical cord blood MSC cells/mice/day), their derived exosomes (the MSC-Exo group that received exosomes derived from 1 × 105 MSC cells/mice/day), or the same volume of PBS. Before administration, the potency of MSCs and their exosomes was evaluated in vitro by T cell activation experiments. After day 7 of the treatments, blood samples and pancreatic tissues were collected. Histochemistry was performed to check cellular architecture and β cell regeneration. In body weight, blood glucose level, and insulin level, cell proliferation assay was done to confirm regeneration of cells after MSC and MSC-Exo treatments. Hyperglycemia was also attenuated in these mice with a concomitant increase in insulin production and an improved histological structure compared to mice in the PBS-treated group. We found increased expression of genes associated with tissue regeneration pathways, including Reg2, Reg3, and Amy2b in the pancreatic tissue of mice treated with MSC or MSC-Exo relative to PBS-treated mice. MicroRNA profiling of MSC-derived exosomes showed the presence of miRs that may facilitate pancreatic regeneration by regulating the Extl3-Reg-cyclinD1 pathway. These results demonstrate a potential therapeutic role of umbilical cord blood MSC-derived exosomes in attenuating insulin deficiency by activating pancreatic islets' regenerative abilities.

Influence of fecal microbiota transplantation on gut microbiota composition and neuroinflammation of 3xTg-AD mice.

The gut microbiota, the aggregate of all microbial cells that inhabit the gut, bidirectionally communicates with the brain via cytokines, neurotransmitters, hormones, and secondary metabolites via the gut-brain axis. The gut microbiota is thought to contribute to the development of Alzheimer's disease (AD), characterized by plaque deposition, neurofibrillary tangles, and neuroinflammation. We hypothesize that manipulation of the gut microbiota can alter development of AD pathologies and neuroinflammation via the gut microbiota-brain axis. To further elucidate the role of the gut-brain axis in AD, we performed fecal microbiota transplants (FMT) from aged (52-64 weeks) 3xTg-AD mice, modeling plaques and neurofibrillary tangles, to young 3xTg-AD (n=5) or wild-type mice (n=10). Phosphate buffered saline (PBS) was gavaged into 3xTg-AD (n=5) and wild-type mice (n=10) as a control. For FMT, a fecal slurry from aged 3xTg-AD mice was prepared and given to experimental mice via oral gavage. At 8 weeks, mice were gavaged with FMT or PBS for 5 consecutive days, followed by fortnightly maintenance transplants for 24 weeks. The V4 region of the 16S rRNA gene was sequenced on the Illumina MiSeq. Data were analyzed using QIIME 2. Reverse transcriptase qPCR was used to assess microgliosis, astrocytosis, and Th1/Th2 inflammation in the hippocampus of the FMT cohort at 24 weeks of age. Our results show a shift in microbiome composition in FMT-treated mice when compared to control (PBS-treated) mice. Bacteroides were increased in 3xTg-AD and wild-type mice receiving FMT. At 24 weeks of age, there was no difference in neuroinflammation between mice treated with FMT compared to control (PBS) in 3xTg-AD or wild type mice. We observed partial engraftment of the gut microbiota from aged 3xTg-AD mice in all FMT-treated mice. We demonstrate the ability to transplant an aged gut microbiome into young mice, however we did not observe changes in neuroinflammation at 24 weeks of age. Future studies will evaluate neuroinflammation and neuropathologies at later time points. These studies will contribute to our understanding of how features of the gut microbiota may contribute to AD development.

Intravenous Ig Regulates Anti-Desmoglein 3 IgG Production in B220– Antibody-Producing Cells in Mice with Pemphigus Vulgaris

Intravenous Ig (IVIG) is a treatment option for intractable cases of pemphigus vulgaris (PV), an autoimmune blistering disease caused by autoantibodies against desmoglein 3 (DSG3). To investigate the efficacy of IVIG on autoantibody secretion, we produced PV model mice by adoptive transfer of immunized Dsg3-/- splenocytes to Rag2-/- mice. We found that circulating anti-DSG3 IgG ELISA titer decreased in PV model mice after 5 days of treatment with IVIG compared with PBS-treated mice, whereas the F(ab')2 fragment did not suppress the anti-DSG3 IgG titer. enzyme-linked immunospot assay revealed that IVIG treatment reduced the frequency of anti-DSG3 antibody-secreting cells in the spleen but not in lymph nodes and bone marrow. Moreover, this reduction was observed only in the splenic B220- fraction but not in the B220+ fraction. Furthermore, IVIG decreased the serum levels of anti-DSG3 IgG, even after a significant reduction of its titer, owing to antibody-mediated CD20+ B cell depletion. In addition, IVIG suppressed anti-DSG3 IgG production in B220-CD138+ plasma cells derived from PV model mice exvivo. These results indicate that IVIG reduced autoantibody production in B220- cells containing plasma cells in PV model mice, and this function may indicate one of the mechanisms of action of IVIG on PV.

Natural Killer T Cells Are Involved in Atherosclerotic Plaque Instability in Apolipoprotein-E Knockout Mice.

The infiltration and activation of macrophages as well as lymphocytes within atherosclerotic lesion contribute to the pathogenesis of plaque rupture. We have demonstrated that invariant natural killer T (iNKT) cells, a unique subset of T lymphocytes that recognize glycolipid antigens, play a crucial role in atherogenesis. However, it remained unclear whether iNKT cells are also involved in plaque instability. Apolipoprotein E (apoE) knockout mice were fed a standard diet (SD) or a high-fat diet (HFD) for 8 weeks. Moreover, the SD- and the HFD-fed mice were divided into two groups according to the intraperitoneal injection of α-galactosylceramide (αGC) that specifically activates iNKT cells or phosphate-buffered saline alone (PBS). ApoE/Jα18 double knockout mice, which lack iNKT cells, were also fed an SD or HFD. Plaque instability was assessed at the brachiocephalic artery by the histological analysis. In the HFD group, αGC significantly enhanced iNKT cell infiltration and exacerbated atherosclerotic plaque instability, whereas the depletion of iNKT cells attenuated plaque instability compared to PBS-treated mice. Real-time PCR analyses in the aortic tissues showed that αGC administration significantly increased expressional levels of inflammatory genes such as IFN-γ and MMP-2, while the depletion of iNKT cells attenuated these expression levels compared to those in the PBS-treated mice. Our findings suggested that iNKT cells are involved in the exacerbation of plaque instability via the activation of inflammatory cells and upregulation of MMP-2 in the vascular tissues.

The IL-2/IL-15 Mimetic NL-201 Prevents Myeloma Relapse after ASCT By Expanding Highly Cytolytic T Cells in the Bone Marrow That Are Resistant to Exhaustion

Multiple myeloma (MM) is a bone marrow (BM) resident hematological malignancy that is becoming increasingly recognized as one amenable to immunotherapy, although no therapies have yet provided durable, long-term disease control. Autologous stem cell transplantation (ASCT), the standard of care in eligible patients, provides a window for intervention with immunotherapy due to the induction of inflammation in the context of lymphodepletion at a time where there is also minimal residual disease and a disrupted tumor microenvironment (TME). We have previously established that the addition of T cells to BM grafts results in enhanced long-term myeloma control post-transplant in mice. Novel approaches aimed at improving and/or expanding the endogenous T cell response early post-ASCT may therefore prove highly effective with the benefit of avoiding ex vivo processing associated with other cellular therapies. To explore this, we utilized the IL-2/IL-15 mimetic NL-201: a de novo cytokine mimetic that signals via the beta and gamma subunits of the IL-2 receptor without engaging IL-2Rα (CD25). In pre-clinical studies, NL-201 has demonstrated the ability to signal to effector CD4 and CD8 T cells while avoiding the toxicity usually associated with IL-2 signaling via IL-2Rα.We hypothesized that NL-201 would enhance control of myeloma progression by stimulating T cell proliferation and activation early post-ASCT. We transplanted lethally irradiated Vk*MYC myeloma-bearing B6 recipients with BM and T cells graft from B6 donors and administered NL-201 from D+7 to week 6 (225 μg/kg weekly I.P). NL-201 promoted potent anti-myeloma immunity that was dependent on CD4 and CD8 T cells, but not NK cells (median survival was 68 days for control mice, unreached at >120 days for NL-201 alone or with NK depletion, 86 days for NL-201 with CD8 depletion, and 74 days with CD4 depletion; PBS vs NL-201 p<0.01; PBS vs NL-201 + αNK1.1 p<0.01; NL-201 vs NL-201 + αCD4 or αCD8 p<0.05). To further elucidate potential mechanisms of action we harvested BM from PBS and NL-201-treated mice 2 days after the last dose was administered and performed comprehensive immunophenotyping with high parameter flow cytometry. We grouped recipients based on whether they had controlled myeloma (MM-controlled) or had active disease progression at the time of harvest (MM-relapsed) to reveal immunological phenotypes that were dependent and independent of myeloma in the TME. In these experiments, all NL-201-treated recipients had controlled myeloma at time of harvest. Mechanistically, NL-201 significantly expanded the total number of CD8 T cells in the BM compared to PBS-treated mice with controlled or relapsed MM (PBS-treated mean CD8 T cell number was 1.0 x 10 5/femur vs 7.7 x 10 5/femur in NL-201-treated mice) but did not impact CD8 T cell number in peripheral blood. Memory CD8 T cells (CD44+CD62L+) were preferentially expanded, while the frequency of exhausted CD8 T cells (TOX +PD-1 +TIGIT +CD39 +; T EX) was reduced in NL-201-treated mice compared to both PBS-treated MM-relapsed and MM-controlled mice (75% T EX in PBS MM-relapsed, 15% PBS MM-controlled, 2% in NL-201; p<0.001). Surprisingly, >80% of the memory CD8 T cells in NL-201-treated mice produced granzyme B compared to <10% in PBS-treated mice. Granzyme B production was also observed in conventional CD4 T cells in response to NL-201 treatment, and the frequency of regulatory T cells was reduced by 50% after NL-201 compared to PBS MM-controlled and MM-relapsed mice (p<0.001).NL-201 expanded bone marrow resident cytotoxic memory CD8 and CD4 T cells that are resistant to exhaustion, whilst reducing the frequency of regulatory T cells in the BM TME. Together, these data highlight the promising therapeutic potential of NL-201 in multiple myeloma and support testing NL-201 in clinical trials for the treatment of hematological malignancies. DisclosuresHill: NapaJen Pharma: Consultancy; Roche: Research Funding; Syndax Pharmaceuticals: Research Funding; iTeos Therapeutics: Consultancy, Research Funding; Applied Molecular Transport: Research Funding; Compass Therapeutics: Research Funding; NeoLeukin Therapeutics: Consultancy; Generon Corporation: Consultancy.

Polyethylenimine grafted-chitosan based Gambogic acid copolymers for targeting cancer cells overexpressing transferrin receptors

Recent advancements in gene delivery systems that specifically target a variety of cancer types have increased demand for tissue-specific gene therapy. The current study describes the synthesis of a copolymer (GPgWSC) composed of a polyethylenimine (PEI)-grafted water-soluble chitosan (WSC) and gambogic acid (GA). It was validated as a ligand capable of enabling targeted attachment to transferrin receptors in HCT116 cancer cell lines. GPgWSC demonstrated superior antitumor activity in vitro in HCT116 compared to LoVo or MCF-7 cell lines, facilitated by the apoptotic activity of psiRNA-hBCL2. Pre-incubation of transferrin significantly inhibited GFP expression in the GPgWSC polyplex, demonstrating that GA is an extremely effective transferrin receptor targeting molecule. Additionally, in the HCT116-bearing mouse model, the tumor mass of PBS-treated mice increased to 2270 mm2 after 22 days, but the injection of GPgWSC polyplex significantly reduced the mass-increasing rate as a mass size of 248 mm2.

G-CSF and IL-6 may be involved in formation of endometriosis lesions by increasing the expression of angiogenic factors in neutrophils.

Evidence accumulated in recent years has revealed that neutrophils are involved in the initial establishment of endometriosis, which is well-known as a chronic inflammatory disease. So far, why and how neutrophils promote the formation of early endometriosis are still unclear. In this study, using a mouse model of endometriosis, we demonstrated that endometriosis mice (EMs mice) had a significantly increased number of neutrophils in peritoneal fluids and lesions, and increased levels of granulocyte colony-stimulating factor (G-CSF) and IL-6 in serum and peritoneal fluids compared to the control group. In the neutrophils and uterine fragments co-injection experiment, neutrophils regulated by G-CSF and IL-6 had a similar effect to neutrophils from EMs mice, increasing the number, area, weight and microvessel density (MVD) of endometriotic lesions. Blocking the effect of G-CSF and IL-6 in EMs mice resulted in a decrease in the number, area and weight of endometriotic lesions. Following the depletion of neutrophils in vivo using a anti-Ly6G antibody, the MVD in the lesions of mice treated with neutrophils from EMs mice and neutrophils from pG/pI6 mice were significantly reduced. Neutrophils from EMs mice and neutrophils from pG/pI6 mice altered the expression levels of Mmp9, Bv8 and Trail genes compared to the neutrophils from PBS-treated mice. IL-6 together with G-CSF induced a higher expression of phospho-STAT3 and STAT3 in neutrophils. These findings suggest that neutrophils modulated by G-CSF and IL-6 through the STAT3 pathway alter the expression levels of the angiogenesis-related genes Mmp9, Bv8 and Trail, and may promote the establishment of early endometriosis.

Activated myofibroblasts promote cardiac hypertrophy and systolic dysfunction independently of cardiac fibrosis in experimental autoimmune myocarditis

Abstract Background/Introduction Heart-specific inflammation – myocarditis is a common cause dilated cardiomyopathy which is characterized by pathological tissue remodeling, ventricular stiffening, cardiomyopathy and heart failure. In experimental autoimmune myocarditis (EAM) susceptible mice immunized with alpha myosin heavy chain (αMyHC) and complete Freund's adjuvant (CFA) develop acute myocarditis driven by autoreactive CD4+ T cells that is followed by progressive fibrosis, cardiomyopathy and systolic dysfunction. Purpose The aim of the study was to investigate the role of cardiac fibroblasts and myofibroblasts in myocarditis and post-inflammatory dilated cardiomyopathy in mouse model of EAM. Methods EAM was induced in BALB/c mice by immunization with αMyHC/CFA. We used reporter mice expressing EGFP under collagen type I promoter (Coll-EGFP) and RFP under a control of α-smooth muscle actin (αSMA) promoter (αSMA-RFP) and transgenic αSMA-TK mice with ganciclovir-inducible ablation of proliferating myofibroblasts. Cardiac cells were quantified using flow cytometry. Cardiac fibroblasts (CD45-CD31-EGFP+) were sorted from healthy and myocarditis-positive (day 21) mice using BD FACSAria™ II Cell Sorter and analyzed for the whole genome transcriptomics by RNA sequencing. Echocardiography was performed on Vevo 2100 Imaging System. Cardiac fibrosis was assessed by Trichrome Massons's staining and hydroxyproline assay, whereas cardiac hypertrophy by analysing cross-sectional cardiomyocyte area. Profibrotic gene expression was assessed by qRT-PCR. Results The total number of cardiac fibroblasts (CD45-CD31-EGFP+) and the subset of myofibroblasts (CD45-CD31-EGFP+RFP+) remained unchanged at inflammatory (d21) and fibrotic stages (d40). Analysis of differentially expressed genes (min. 2x fold change, p value &amp;lt;0.05) pointed out activation of immune processes (mainly chemokine production), response to stress, cytoskeletal and extracellular matrix re-organization in cardiac fibroblasts in response to myocarditis. αSMA-TK mice treated with ganciclovir (from day 21) showed comparable percent of fibrotic area, but significantly reduced heart weight, decreased cardiomyocyte hypertrophy and improved ejection fraction and cardiac output at day 40 comparing to PBS-treated mice. Ganciclovir-treated mice showed also attenuated cardiac Acta2 and Srf but markedly enhanced Mmp2 expression. Conclusions In EAM model cardiac fibroblasts actively participate in proinflammatory and profibrotic responses, while activated myofibroblasts contribute to dilated cardiomyopathy development independently of cardiac fibrosis. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): National Science Centre (Poland)

Bleomycin-Induced Lung Injury Increases Resistance to Influenza Virus Infection in a Type I Interferon-Dependent Manner.

Acute lung injury (ALI) results in acute respiratory disease that causes fatal respiratory diseases; however, little is known about the incidence of influenza infection in ALI. Using a ALI-mouse model, we investigated the pro-inflammatory cytokine response to ALI and influenza infection. Mice treated with bleomycin (BLM), which induces ALI, were more resistant to influenza virus infection and exhibited higher levels of type I interferon (IFN-I) transcription during the early infection period than that in PBS-treated control mice. BLM-treated mice also exhibited a lower viral burden, reduced pro-inflammatory cytokine production, and neutrophil levels. In contrast, BLM-treated IFN-I receptor 1 (IFNAR1)-knockout mice failed to show this attenuated phenotype, indicating that IFN-I is key to the antiviral response in ALI-induced mice. The STING/TBK1/IRF3 pathway was found to be involved in IFN-I production and the establishment of an antiviral environment in the lung. The depletion of plasmacytoid dendritic cells (pDCs) reduced the effect of BLM treatment against influenza virus infection, suggesting that pDCs are the major source of IFN-I and are crucial for defense against viral infection in BLM-induced lung injury. Overall, this study showed that BLM-mediated ALI in mice induced the release of double-stranded DNA, which in turn potentiated IFN-I-dependent pulmonary viral resistance by activating the STING/TBK1/IRF3 pathway in association with pDCs.

Modulation of Peripheral CD4+CD25+Foxp3+ Regulatory T Cells Ameliorates Surgical Stress-Induced Atherosclerotic Plaque Progression in ApoE-Deficient Mice.

Systemic inflammation associated with major surgery rapidly accelerates atherosclerotic plaque progression in mice. Regulatory T cells (Tregs) have emerged as important modulators of atherogenesis. In coronary artery disease patients, low frequency of Tregs constitutes an independent risk factor for cardiovascular complications after non-cardiac surgery. In this exploratory analysis, we investigate whether preoperative Treg levels affect surgery-induced atherosclerotic lesion destabilization in a murine model of perioperative stress. After 9 weeks of high-cholesterol diet, atherosclerotic apolipoprotein E-deficient mice with modulated Treg levels were subjected to a 30-minute surgical procedure consisting of general isoflurane anesthesia, laparotomy and moderate blood loss. Controls underwent general anesthesia only. Brachiocephalic arteries were harvested 3 days after the intervention for histomorphological analyses of atherosclerotic plaques. Tregs were depleted by a single dose of anti-CD25 monoclonal antibody (mAb) administered 6 days prior to the intervention. Expansion of Tregs was induced by daily injections of IL-2/anti-IL-2 complex (IL-2C) on three consecutive days starting 3 days before surgery. Isotype-matched antibodies and PBS served as controls. Antibody-mediated modulation was Treg-specific. IL-2C treatment resulted in an eight-fold elevation of peripheral CD4+CD25+Foxp3+ Tregs compared to mice administered with anti-CD25 mAb. In mice treated with PBS and anti-CD25 mAb, surgical stress response caused a significant increase of atherosclerotic plaque necrosis (PBS: p < 0.001; anti-CD25 mAb: p = 0.037). Preoperative Treg expansion abrogated perioperative necrotic core formation (p = 0.556) and significantly enhanced postoperative atherosclerotic plaque stability compared to PBS-treated mice (p = 0.036). Postoperative plaque volume (p = 0.960), stenosis (p = 0.693), lesional collagen (p = 0.258), as well as the relative macrophage (p = 0.625) and smooth muscle cell content (p = 0.178) remained largely unaffected by preoperative Treg levels. In atherosclerotic mice, therapeutic expansion of Tregs prior to major surgery mitigates rapid effects on perioperative stress-driven atherosclerotic plaque destabilization. Future studies will show, whether short-term interventions modulating perioperative inflammation qualify for prevention of cardiovascular events associated with major non-cardiac surgery.

Antisense oligonucleotide treatment rescues UBE3A expression and multiple phenotypes of an Angelman syndrome mouse model

Angelman syndrome (AS) is a severe neurodevelopmental disorder for which only symptomatic treatment with limited benefits is available. AS is caused by mutations affecting the maternally inherited ubiquitin protein ligase E3A (UBE3A) gene. Previous studies showed that the silenced paternal Ube3a gene can be activated by targeting the antisense Ube3a-ATS transcript. We investigated antisense oligonucleotide–induced (ASO-induced) Ube3a-ATS degradation and its ability to induce UBE3A reinstatement and rescue of AS phenotypes in an established Ube3a mouse model. We found that a single intracerebroventricular injection of ASOs at postnatal day 1 (P1) or P21 in AS mice resulted in potent and specific UBE3A reinstatement in the brain, with levels up to 74% of WT levels in the cortex and a full rescue of sensitivity to audiogenic seizures. AS mice treated with ASO at P1 also showed rescue of established AS phenotypes, such as open field and forced swim test behaviors, and significant improvement on the reversed rotarod. Hippocampal plasticity of treated AS mice was comparable to WT but not significantly different from PBS-treated AS mice. No rescue was observed for the marble burying and nest building phenotypes. Our findings highlight the promise of ASO-mediated reactivation of UBE3A as a disease-modifying treatment for AS.

Stachyose inhibits vancomycin-resistant Enterococcus colonization and affects gut microbiota in mice

Vancomycin-resistant Enterococcus (VRE) caused nosocomial infections are rising globally. Multiple measures have been investigated to address this issue, altering gut microbiota through dietary intervention represents one of such effort. Stachyose can promote probiotic growth, which makes it a good candidate for potentially inhibiting VRE infection. This study aimed to determine whether stachyose inhibits VRE colonization and investigated the involvement of gut microbiota this effect of stachyose. In VRE-infection experiment, 6-week old female C57/6 J mice pre-treated with vancomycin were infected with 2 × 108 CFU VRE via gavage. These mice then received oral administration of stachyose or PBS as control for 7days. Two groups of uninfected mice were also received daily gavage of stachyose or PBS for 7 days to observe the impact of stachyose treatment on normal mice. Fresh fecal and colon samples were collected, then VRE colonization, gut microbiota and gene expression were respectively assessed using cultivation, 16s rRNA sequencing and RNA-sequencing in two parallel experiment, respectively. In VRE-infected mice, stachyose treatment significantly reduced VRE colonization on days 9 and 10 post-infection. Stachyose treatment increased the relative abundance of Porphyromonadaceae, Parabacteroides, and Parabacteroides distasonis compared to the PBS-treated infection mice (P < 0.01). Uninfected mice treated with stachyose showed a significant increase in Lactobacillaceae and Lactobacillus compared to the PBS-treated uninfected mice(P < 0.05). RNA-sequencing results showed that stachyose treatment in VRE-infected mice increased expression of genes involved in TNF and IL-17 signaling pathways. Stachyose treatment also up-regulated Hsd17b14, Cyp3a44, Arg1, and down-regulated Pnliprp2, Ces1c, Pla2g4c genes involving in metabolic pathway in uninfected mice. In conclusion, stachyose supplementation can effectively inhibit VRE colonization and probably altering composition of the microbiome, which can in turn result in changes in expression of genes. Stachyose may also benefit health by increasing the abundance of Lactobacillus and expression of genes involving in metabolic pathway in normal mice.

Favipiravir treatment prolongs the survival in a lethal mouse model intracerebrally inoculated with Jamestown Canyon virus.

BackgroundJamestown Canyon virus (JCV) is a mosquito-borne orthobunyavirus that causes acute febrile illness, meningitis, and meningoencephalitis, primarily in North American adults. Currently, there are no available vaccines or specific treatments against JCV infections.Methodology/Principal findingsThe antiviral efficacy of favipiravir (FPV) against JCV infection was evaluated in vitro and in vivo in comparison with that of ribavirin (RBV) and 2’-fluoro-2’-deoxycytidine (2’-FdC). The in vitro inhibitory effect of these drugs on JCV replication was evaluated in Vero and Neuro-2a (N2A) cells. The efficacy of FPV in the treatment of JCV infection in vivo was evaluated in C57BL/6J mice inoculated intracerebrally with JCV, as per the survival, viral titers in the brain, and viral RNA load in the blood. The 90% inhibitory concentrations (IC90) of FPV, RBV, and 2’-FdC were 41.0, 61.8, and 13.6 μM in Vero cells and 20.7, 25.8, and 8.8 μM in N2A cells, respectively. All mice infected with 1.0×104 TCID50 died or were sacrificed within 10 days post-infection (dpi) without treatment. However, mice treated with FPV for 5 days [initiated either 2 days prior to infection (−2 dpi–2 dpi) or on the day of infection (0 dpi–4 dpi)] survived significantly longer than control mice, administered with PBS (p = 0.025 and 0.011, respectively). Moreover, at 1 and 3 dpi, the virus titers in the brain were significantly lower in FPV-treated mice (0 dpi–4 dpi) versus PBS-treated mice (p = 0.002 for both 1 and 3 dpi).Conclusions/SignificanceAlthough the intracerebral inoculation route is thought to be a challenging way to evaluate drug efficacy, FPV inhibits the in vitro replication of JCV and prolongs the survival of mice intracerebrally inoculated with JCV. These results will enable the development of a specific antiviral treatment against JCV infections and establishment of an effective animal model.

Abstract 1844: A CD70 antibody-drug conjugate is highly active and induces long term remission in patient-derived xenograft mouse models of cutaneous T cell lymphoma

Abstract Cutaneous T cell lymphoma (CTCL) is a type of non-Hodgkin's lymphoma in which malignant T cells initially home to the skin followed by systemic dissemination as the disease progresses. CD70 is rarely expressed in normal tissues but is overexpressed in activated T and B lymphocytes. From archival diagnostic specimens of 37 patients, we demonstrate that CD70 is highly expressed in subtypes of mature TCL, especially CTCL. SGNCD70A is a new anti-CD70 antibody-drug conjugate combining a monoclonal antibody to CD70 with a DNA-damaging agent. SGNCD70A inhibited cell growth and induced apoptosis of CD70+ CTCL cell lines and primary tumors from patient-derived xenograft (PDX) mice, but had no inhibitory effect on CD70- lymphoblastic TCL cells and normal T cells. Next, we examined the anti-tumor activity of SGNCD70A in CTCL PDX model. One week after tumor inoculation, mice were treated intraperitoneally with single-dosing of PBS, 100 μg/kg (SGN70A100) or 300 μg/kg (SGN70A300) of SGN-CD70A. SGN-CD70A prolonged survival of treated mice in a dose-dependent fashion compared to untreated mice. Median survival was 21 days, 27.5 days (P=0.041), and 57 days (p&amp;lt;0.01) for the PBS control, SGN70A100 and SGN70A300 group, respectively. To confirm that survival was dictated by disease progression, rather than drug toxicity of SGN-CD70A, we measured tumor burden by cell-free DNA (cfDNA) throughout the course of treatment. We demonstrated that cfDNA paralleled the disease progression and peaked before death of the animals. In contrast, in surviving mice, cfDNA remained at the background level. Importantly, we discovered relapse occurred in SGN70A300 group (3 of 4, 75%) due to persistent disease, not due to acquired resistance to SGN-CD70A. Thus, we investigated whether multiple dosing could lead to complete regression of tumors in PDX model. We treated PDX mice with SGN70A300 weekly (SGN70A300x3) for 3 consecutive weeks. In the SGN70A300x3 group, three of four mice survived beyond day 90 (median &amp;gt;85 days), resulting in markedly prolonged survival compared to the single-dose- and PBS-treated mice with a median survival of 39 days, (P&amp;lt;0.01) and 20 days (P&amp;lt;0.01), respectively. Compared to PBS group, both SGN70A300 and SGN70A300x3 treated mice had delayed tumor growth and cfDNA rise. Furthermore, in SGN70A300 group, cfDNA started to rise seven days before the endpoint of the mice in a range of 30-42 days, while three surviving mice in SGN70A300x3 remained at background cfDNA levels until day 85, indicating that multiple doses of SGN-CD70A decreased overall tumor burden and the occurrence of relapse in CTCL. Our results showed that CD70 is highly expressed in mature TCL, especially in CTCL. Using CTCL PDX models, SGN-CD70A has marked anti-tumor activity, leading to long-term survival of treated mice. Our results provide a rationale for clinical investigation of SGN-CD70A in patients with TCL. Citation Format: Chi-Heng Wu, Chen-Yen Yang, Linlin Wang, Ryan Gill, Frank McCormick, Weiyun Z. Ai. A CD70 antibody-drug conjugate is highly active and induces long term remission in patient-derived xenograft mouse models of cutaneous T cell lymphoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1844.

Abstract 1489: Deposition of genetically engineered T cell attracting antigen presenting cells in the glioma microenvironment with low intensity pulsed ultrasound-based blood-brain barrier opening triggers therapeutic responses in preclinical glioma models

Abstract Introduction: In contrast to brain metastases, gliomas have few antigen-presenting cells (APCs) in the tumor microenvironment, which may limit T cell effector responses. We hypothesized that: (1) an APC could be modified to express a T cell attracting chemokine that could enhance localized immune activation, and (2) that ultrasound-based blood-brain barrier (BBB) opening would enhance delivery of these APCs at the site of tumor antigens. Methods: Murine F4/80 and CD11c expressing APCs were isolated from the bone marrow of C57BL/6 mice and modified via lentiviral transduction to encode the cDNA of immune cell chemokines CXCL9 or CXCL10 and methionine-deficient green fluorescent protein (co-expression) for cell tagging. C57BL/6 mice were implanted with GL261 cells and treated with 1 x 106 CXCL9 or CXCL10 over-expressing APCs intracranially (i.c.), or intravenously (i.v.) with or without ultrasound-based BBB opening. To determine how the CXCL10 expressing APCs were altering the tumor microenvironment, immune cells were isolated from the glioma implanted hemisphere of all treatment groups and analyzed by multicolor flow cytometry. Results: Transduced APCs produced 3,392 pg/ml and 2,987 pg/ml of CXCL9 or CXCL10, respectively. Mice tolerated the treatments well without any adverse events, behavioral changes, or neurological toxicity. Survival analysis of mice treated with CXCL9 expressing APCs using i.c., or i.v. with and without BBB opening ultrasound showed no significant survival benefit compared with PBS-treated control mice. Mice treated i.c. with CXCL10-expressing APCs had significantly improved survival relative to the PBS control group (p&amp;lt;0.05), demonstrating that this cellular therapy required access to the tumor microenvironment in order to be effective. Notably, the most therapeutically efficacious administration route was when the CXCL10-expressing APCs were administered i.v. before ultrasound-based BBB opening even relative to the i.c. administered group (p&amp;lt;0.05). Intravenous administration of CXCL10 APCs combined with ultrasound-based BBB opening also significantly increased the percentage of T cells in the glioma microenvironment relative to all other treatment groups. Conclusions: The delivery of CXCL10-secreting APCs to the glioma microenvironment with ultrasound-based BBB opening was superior to delivery with direct i.c. injection. BBB disruption may have triggered more diffuse dispersal of the APCs throughout the tumor microenvironment or positioned these cells in closer proximity to the T cells emigrating from the vascular space into the localized glioma microenvironment. Citation Format: Aria Sabbagh, Kevin Beccaria, Xiaoyang Ling, Anantha Marisetty, Martina Ott, Ling-Yuan Kong, Dexing Fang, Jun Wei, Carole Desseaux, Guillaume Bouchoux, Michael Canney, Alexandre Carpentier, Amy B. Heimberger. Deposition of genetically engineered T cell attracting antigen presenting cells in the glioma microenvironment with low intensity pulsed ultrasound-based blood-brain barrier opening triggers therapeutic responses in preclinical glioma models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1489.

Abstract LB181: Autologous glioblastoma tumor cells treated with an antisense oligonucleotide against insulin-like growth factor type 1 receptor protect mice against GL261 tumor challenge

Abstract Background: Despite the current standard of care (SOC) established by Stupp et al (N Engl J Med. 2005:10;352:987-96), patients with glioblastoma continue to have a poor prognosis. IGV-001 is a novel immunotherapy that combines irradiated, patient-derived glioblastoma tumor cells and an antisense oligonucleotide against insulin-like growth factor type 1 receptor (IMV-001) in biodiffusion chambers (0.1-micron pore size). We recently evaluated IGV-001 in patients with newly diagnosed glioblastoma (Andrews et al. Clin Cancer Res. 2021; in press). In a subgroup of IGV-001-treated, Stupp-eligible patients with methylated O6-methylguanine-DNA methyl-transferase promoter, median progression free survival was 38.4 months (compared with 6.5 months in a historical SOC; P=0.0008). We sought to unravel the potential mechanism associated with the high degree of effectiveness of IGV-001 in patients using the GL261-luciferase (-Luc) glioblastoma orthotopic murine model. Methodology: Biodiffusion chambers (0.1- or 5-micron pore size for comparison) containing phosphate-buffered saline (PBS) alone or IGV-001 prepared with 1×106 GL261-Luc cells were implanted in the flanks of C57BL/6 albino female mice. The chambers were explanted after 48 hours (as done in the clinical protocol), followed by intracranial tumor challenge with GL261-Luc cells 26 days after chamber removal. Mice were monitored for survival and tumor growth. FluoroSpot assays were conducted to determine IFN-gamma production as a surrogate measure of antitumor Th1 cytotoxic lymphocyte (CTL) activity. Results: No mice died of disease in either IGV-001-treated group and continued to gain weight until the termination of the study, 28 days post-intracranial tumor challenge. In comparison, there was only one survivor in the PBS group at termination with a median survival time (MST) of 20 days (P&amp;lt;0.001). At the endpoint, 54% of all IGV-001-treated mice (0.1- and 5-micron chambers combined) presented with only a minimal GL-261-Luc bioluminescent signal (&amp;lt;1×108 photons/sec). FluoroSpot assays revealed that on day 29, post-chamber implantation, the number of IFN-gamma-producing cells in the peripheral blood was significantly greater (P&amp;lt;0.01) in IGV-001-treated versus PBS-treated mice, regardless of chamber size. Conclusions: These data support the antitumor activity of IGV-001 in newly diagnosed glioblastoma as demonstrated in the phase 1 study. The results suggest that IGV-001 effectiveness is at least in part associated with a systemic immunological effect, resulting in the generation of Th1 antitumor CTLs. Follow-up studies are aimed to determine the MST of mice receiving this immunotherapy and the factors triggering complete versus partial responses using phenotypic evaluation of T-cell activation/exhaustion markers and Th1/Th2 cytokine production. Citation Format: Jenny Zilberberg, Samantha Garcia, Amelia Zellander, David W. Andrews, Mark A. Exley. Autologous glioblastoma tumor cells treated with an antisense oligonucleotide against insulin-like growth factor type 1 receptor protect mice against GL261 tumor challenge [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr LB181.

Dynamic Host Immune and Transcriptomic Responses to Respiratory Syncytial Virus Infection in a Vaccination-Challenge Mouse Model.

Respiratory syncytial virus (RSV) is the major cause of lower respiratory tract infections in children. Inactivated RSV vaccine was developed in the late 1960's, but the vaccine-enhanced disease (VED) occurred to vaccinated infants upon subsequent natural RSV infection. The excessive inflammatory immunopathology in the lungs might be involved in the VED, but the underlying mechanisms remain not fully understood. In this study, we utilized UV-inactivated RSV in the prime/boost approach followed by RSV challenge in BALB/c mice to mimic RSV VED. The dynamic virus load, cytokines, histology and transcriptome profiles in lung tissues of mice were investigated from day 1 to day 6 post-infection. Compared to PBS-treated mice, UV-RSV vaccination leads to a Th2 type inflammatory response characterized by enhanced histopathology, reduced Treg cells and increased IL4+CD4 T cells in the lung. Enhanced production of several Th2 type cytokines (IL-4, IL-5, IL-10) and TGF-β, reduction of IL-6 and IL-17 were observed in UV-RSV vaccinated mice. A total of 5582 differentially expressed (DE) genes between PBS-treated or vaccinated mice and naïve mice were identified by RNA-Seq. Eleven conserved high-influential modules (HMs) were recognized, majorly grouped into regulatory networks related to cell cycle and cell metabolism, signal transduction, immune and inflammatory responses. At an early time post-infection, the vaccinated mice showed obvious decreased expression patterns of DE genes in 11 HMs compared to PBS-treated mice. The extracellular matrix (HM5) and immune responses (HM8) revealed tremendous differences in expression and regulation characteristics of transcripts between PBS-treated and vaccinated mice at both early and late time points. The highly connected genes in HM5 and HM8 networks were further validated by RT-qPCR. These findings reveal the relationship between RSV VED and immune responses, which could benefit the development of novel RSV vaccines.