TUSC2 Immunogene Therapy Synergizes with Anti-PD-1 through Enhanced Proliferation and Infiltration of Natural Killer Cells in Syngeneic Kras-Mutant Mouse Lung Cancer Models.

Expression of the multikinase inhibitor encoded by the tumor suppressor gene TUSC2 (also known as FUS1) is lost or decreased in non-small cell lung carcinoma (NSCLC). TUSC2 delivered systemically by nanovesicles has mediated tumor regression in clinical trials. Because of the role of TUSC2 in regulating immune cells, we assessed TUSC2 efficacy on antitumor immune responses alone and in combination with anti-PD-1 in two Kras-mutant syngeneic mouse lung cancer models. TUSC2 alone significantly reduced tumor growth and prolonged survival compared with anti-PD-1. When combined, this effect was significantly enhanced, and correlated with a pronounced increases in circulating and splenic natural killer (NK) cells and CD8+ T cells, and a decrease in regulatory T cells (Tregs), myeloid-derived suppressor cells (MDSCs), and T-cell checkpoint receptors PD-1, CTLA-4, and TIM-3. TUSC2 combined with anti-PD-1 induced tumor infiltrating more than NK and CD8+ T cells and fewer MDSCs and Tregs than each agent alone, both in subcutaneous tumor and in lung metastases. NK-cell depletion abrogated the antitumor effect and Th1-mediated immune response of this combination, indicating that NK cells mediate TUSC2/anti-PD-1 synergy. Release of IL15 and IL18 cytokines and expression of the IL15Rα chain and IL18R1 were associated with NK-cell activation by TUSC2. Immune response-related gene expression in the tumor microenvironment was altered by combination treatment. These data provide a rationale for immunogene therapy combined with immune checkpoint blockade in the treatment of NSCLC. Cancer Immunol Res; 6(2); 163-77. ©2018 AACR.

Role of inhibitor of growth 4 in the suppression of human melanoma cells through the Fas/FasL-mediated apoptosis pathway.

Melanoma, the most aggressive form of skin cancer, is notoriously resistant to all current available therapies. Inhibitor of growth 4 (ING4), a novel member of the ING family of proteins, has previously been shown to play a critical role in the development of multiple tumors by regulating apoptosis, proliferation, cell cycle progress, migration and invasion. However, the functional role of ING4 in human melanoma remains unclear. To fully understand its potential role in human melanoma, in the present study, lentivirus (LV)­ING4 and LV­ING4­short hairpin RNA were constructed and transfected into human melanoma A375 cells. First, the effect of overexpressing or downregulating ING4 on the apoptosis of the transfected melanoma cells and cluster of differentiation (CD)3+ T cells was investigated. In the present study, we found that the late apoptotic cells, and not the early apoptotic cells, were more in LV-ING4 group compared with LV-control, and both the early and late apoptosis of CD3+ T cells was significantly observed in A375 cells transfected with LV-ING4 compared with LV-control. Importantly, it was determined whether the overexpression of ING4 significantly induce apoptotic cell death via Fas/FasL (Fas death receptor/FasL) pathway activation and downregulation of poly(ADP­ribose) polymerase, caspase­3 and caspase­8 in the melanoma cells and CD3+ T cells. These results demonstrated that overexpression of ING4 can induce the apoptosis of melanoma cells and CD3+ T cells through signaling pathways such as the Fas/FasL pathway, and that ING4 gene therapy for melanoma treatment is a novel approach.

Intranasal administration of recombinant Netrin-1 attenuates neuronal apoptosis by activating DCC/APPL-1/AKT signaling pathway after subarachnoid hemorrhage in rats.

Neuronal apoptosis is a crucial pathological process in early brain injury after subarachnoid hemorrhage (SAH). The effective therapeutic strategies to ameliorate neuronal apoptosis are still absent. We intended to determine whether intranasal administration of exogenous Netrin-1 (NTN-1) could attenuate neuronal apoptosis after experimental SAH, specifically via activating DCC-dependent APPL-1/AKT signaling cascade. Two hundred twenty-five male Sprague-Dawley rats were subjected to the endovascular perforation model of SAH. Recombinant human NTN-1 (rNTN-1) was administered intranasally. NTN-1 small interfering RNA (siRNA), APPL-1 siRNA, and AKT inhibitor MK2206 were administered through intracerebroventricular (i.c.v.) injection. SAH grade, neurological score, neuronal apoptosis assessed by cleaved caspase-3 (CC-3) expression and Fluoro-Jade C (FJC) staining, double immunofluorescence staining, and Western blot were examined. Our results revealed that endogenous NTN-1 level was increased after SAH. Administration of rNTN-1 improved neurological outcomes at 24 h and 72 h after SAH, while knockdown of endogenous NTN-1 worsened neurological impairments. Furthermore, exogenous rNTN-1 treatment promoted APPL-1 activation, increased phosphorylated-AKT and Bcl-2 expression, as well as decreased apoptotic marker CC-3 expression and the number of FJC-positive neurons, thereby alleviated neuronal apoptosis. Conversely, APPL-1 siRNA and MK2206 abolished the anti-apoptotic effect of exogenous rNTN-1 at 24 h after SAH. Collectively, intranasal administration of exogenous rNTN-1 attenuated neuronal apoptosis and improved neurological function in SAH rats, at least in apart via activating DCC/APPL-1/AKT signaling pathway.

Low-density lipoprotein receptor-related protein-1 facilitates heme scavenging after intracerebral hemorrhage in mice.

Heme-degradation after erythrocyte lysis plays an important role in the pathophysiology of intracerebral hemorrhage. Low-density lipoprotein receptor-related protein-1 is a receptor expressed predominately at the neurovascular interface, which facilitates the clearance of the hemopexin and heme complex. In the present study, we investigated the role of low-density lipoprotein receptor-related protein-1 in heme removal and neuroprotection in a mouse model of intracerebral hemorrhage. Endogenous low-density lipoprotein receptor-related protein-1 and hemopexin were increased in ipsilateral brain after intracerebral hemorrhage, accompanied by increased hemoglobin levels, brain water content, blood-brain barrier permeability and neurological deficits. Exogenous human recombinant low-density lipoprotein receptor-related protein-1 protein reduced hematoma volume, brain water content surrounding hematoma, blood-brain barrier permeability and improved neurological function three days after intracerebral hemorrhage. The expression of malondialdehyde, fluoro-Jade C positive cells and cleaved caspase 3 was increased three days after intracerebral hemorrhage in the ipsilateral brain tissues and decreased with recombinant low-density lipoprotein receptor-related protein-1. Intracerebral hemorrhage decreased and recombinant low-density lipoprotein receptor-related protein-1 increased the levels of superoxide dismutase 1. Low-density lipoprotein receptor-related protein-1 siRNA reduced the effect of human recombinant low-density lipoprotein receptor-related protein-1 on all outcomes measured. Collectively, our findings suggest that low-density lipoprotein receptor-related protein-1 contributed to heme clearance and blood-brain barrier protection after intracerebral hemorrhage. The use of low-density lipoprotein receptor-related protein-1 as supplement provides a novel approach to ameliorating intracerebral hemorrhage brain injury via its pleiotropic neuroprotective effects.

Therapeutic Effects of Erythroid Differentiation Regulator 1 on Imiquimod-Induced Psoriasis-Like Skin Inflammation.

Psoriasis is a common skin disease accompanied by chronic inflammation. In previous studies, erythroid differentiation regulator 1 (ERDR1) was shown to have a negative correlation with proinflammatory cytokine IL-18. However, the role of ERDR1 in the inflammatory skin disease psoriasis has not been evaluated. In this study, to investigate the role of ERDR1 in psoriasis, recombinant ERDR1 was injected intraperitoneally into a psoriasis mouse model. Recombinant ERDR1 (rERDR1) significantly alleviated the symptoms of psoriasis-like skin inflammation and reduced the mRNA of various psoriasis-related markers, including keratin 14, S100A8, and Th17-related cytokines IL-17 and IL-22, suggesting that rERDR1 exerts therapeutic effects on psoriasis via the regulation of Th17 functions. Additionally, the expression of CCL20, a well-known Th17 attracting chemokine, was determined. CCL20 expression significantly decreased in the rERDR1-injected group compared with the vehicle (PBS)-injected group. CCR6 expression in the psoriatic lesional skin was also decreased by rERDR1 administration, implying the inhibition of CCR6-expressing Th17 cell chemotaxis via the downregulation of CCL20. Taken together, this study provides the first evidence that ERDR1 may be a potential therapeutic target for psoriasis.

Effects of intravitreal injection of netrin-1 in retinal neovascularization of streptozotocin-induced diabetic rats.

BACKGROUND: In a previous study, we confirmed that netrin-1 acts as an antiangiogenic factor by inhibiting alkali burn-induced corneal neovascularization in rats. Here, we continue working on the role of netrin-1 in retinal neovascularization. METHODS: Using an in vitro angiogenesis assay, we detected the effects of netrin-1 on human umbilical vein endothelial cell tube formation, viability and proliferation, migration, and invasion at concentrations of 0.1 µg/mL or 5 µg/mL. We intravitreally injected 0.1 µg/mL or 5 µg/mL netrin-1 into streptozotocin-induced rats to assess retinal neovascularization using retinal electrophysiology and electroretinography, enzyme-linked immunosorbent assay, fundus fluoresce in angiography, measurement of inner blood retinal barrier, retinal hematoxylin-eosin staining, and retinal flat-mount fluorescence assays. RESULTS: Human umbilical vein endothelial cell tube formation, viability and proliferation, migration, and invasion were upregulated by netrin-1 at a concentration of 0.1 µg/mL (P<0.05), while 5 µg/mL netrin-1 had an opposite effect (P<0.05) in our in vitro angiogenesis assay. Retinal electrophysiology testing revealed that intravitreal injection of netrin-1 affected the amplitude of a- and b-waves (a-wave: 0.1 µg/mL netrin-1 =17.67±3.39 µm, 5 µg/mL netrin-1 =28.50±1.31 µm, phosphate-buffered saline [PBS]-treated =17.67±3.39 µm; b-wave: 0.1 µg/mL netrin-1 =44.67±4.80 µm, 5 µg/mL netrin-1 =97.17±9.63 µm, PBS-treated =44.67±4.80 µm) and the expression of VEGF-A (no-treatment rats, 9.29±0.80 pg/mL; PBS-treated rats, 19.64±3.77 pg/mL; 0.1 µg/mL netrin-1 treated rats, 21.37±3.64 pg/mL; 5 µg/mL netrin-1 treated rats, 9.85±0.54 pg/mL, at 6 weeks after induction). By comparing fluoresce in angiography, level of inner blood retinal barrier breakdown (% of control), retinal hematoxylin-eosin staining, and collagen-IV fluorescence assays in the retinas of PBS-treated rats, netrin-1 was found to suppress and reverse retinal neovascularization at a concentration of 5 µg/mL (P<0.05), while 0.1 µg/mL netrin-1 (P<0.05) led to an increase in the number of new retinal blood vessels, after 6 weeks' injection. CONCLUSION: Netrin-1 could play a significant role in retinal neovascularization by dual-direction regulating angiogenesis dependent on dosage.

Neuron Subpopulations with Different Elongation Rates and DCC Dynamics Exhibit Distinct Responses to Isolated Netrin-1 Treatment.

Correct wiring of the nervous system requires guidance cues, diffusible or substrate-bound proteins that steer elongating axons to their target tissues. Netrin-1, the best characterized member of the Netrins family of guidance molecules, is known to induce axon turning and modulate axon elongation rate; however, the factors regulating the axonal response to Netrin-1 are not fully understood. Using microfluidics, we treated fluidically isolated axons of mouse primary cortical neurons with Netrin-1 and characterized axon elongation rates, as well as the membrane localization of deleted in colorectal cancer (DCC), a well-established receptor of Netrin-1. The capacity to stimulate and observe a large number of individual axons allowed us to conduct distribution analyses, through which we identified two distinct neuron subpopulations based on different elongation behavior and different DCC membrane dynamics. Netrin-1 reduced the elongation rates in both subpopulations, where the effect was more pronounced in the slow growing subpopulation. Both the source of Ca(2+) influx and the basal cytosolic Ca(2+) levels regulated the effect of Netrin-1, for example, Ca(2+) efflux from the endoplasmic reticulum due to the activation of Ryanodine channels blocked Netrin-1-induced axon slowdown. Netrin-1 treatment resulted in a rapid membrane insertion of DCC, followed by a gradual internalization. DCC membrane dynamics were different in the central regions of the growth cones compared to filopodia and axon shafts, highlighting the temporal and spatial heterogeneity in the signaling events downstream of Netrin-1. Cumulatively, these results demonstrate the power of microfluidic compartmentalization and distribution analysis in describing the complex axonal Netrin-1 response.

Netrin-1 abrogates ischemia/reperfusion-induced cardiac mitochondrial dysfunction via nitric oxide-dependent attenuation of NOX4 activation and recoupling of NOS.

Despite an established role of mitochondrial dysfunction in cardiac ischemia/reperfusion (I/R) injury, the upstream activators have remained incompletely defined. We have recently identified an innovative role of exogenously applied netrin-1 in cardioprotection, which is mediated by increased nitric oxide (NO) bioavailability. Here, we tested the hypothesis that this "pharmacological" treatment of netrin-1 preserves mitochondrial function via novel mechanisms that are NO dependent. Freshly isolated C57BL6 mouse hearts were perfused using a Langendorff system, and subjected to a 20min global ischemia/60min reperfusion, in the presence or absence of netrin-1. I/R induced marked increases in infarct size, total superoxide and hydrogen peroxide production, activity and protein abundance of NADPH oxidase (NOX) isoform 4 (NOX4), as well as impaired mitochondrial integrity and function, all of which were attenuated by netrin-1. This protective effect of netrin-1 is attributed to cGMP, a downstream effector of NO. The protein levels of NOX1 and NOX2 were however unaffected, and infarct size from NOX1 and NOX2 knockouts was not different from wild type animals. Scavenging of NO with PTIO reversed inhibitory effects of netrin-1 on NOX4, while NO donor attenuated NOX4 protein abundance. In vivo NOX4 RNAi, or sepiapterin perfusion, resulted in recoupling of NOS, decreased infarct size, and blockade of dysfunctional mitochondrial swelling and mitochondrial superoxide production. These data demonstrate that netrin-1 induces cardioprotection through inhibition of NOX4 activity, which leads to recoupling of NOS, augmented NO bioavailability, reduction in oxidative stress, and ultimately preservation of mitochondrial function. The NO-dependent NOX4 inhibition connects with our previously established pathway of DCC/ERK1/2/eNOS/NO/DCC feed-forward mechanism, to maintain NOS in the coupling state to attenuate oxidative stress to preserve mitochondrial function. These findings may promote development of novel therapeutics for cardiac I/R injury. This article is part of a Special Issue entitled "Mitochondria: From Basic Mitochondrial Biology to Cardiovascular Disease".

Wilms tumor gene (WT1) peptide-based cancer vaccine combined with gemcitabine for patients with advanced pancreatic cancer.

Wilms tumor gene (WT1) protein is an attractive target for cancer immunotherapy. We aimed to investigate the feasibility of a combination therapy consisting of gemcitabine and WT1 peptide-based vaccine for patients with advanced pancreatic cancer and to make initial assessments of its clinical efficacy and immunologic response. Thirty-two HLA-A*24:02 patients with advanced pancreatic cancer were enrolled. Patients received HLA-A*24:02-restricted, modified 9-mer WT1 peptide (3 mg/body) emulsified with Montanide ISA51 adjuvant (WT1 vaccine) intradermally biweekly and gemcitabine (1000 mg/m) on days 1, 8, and 15 of a 28-day cycle. This combination therapy was well tolerated. The frequencies of grade 3-4 adverse events for this combination therapy were similar to those for gemcitabine alone. Objective response rate was 20.0% (6/30 evaluable patients). Median survival time and 1-year survival rate were 8.1 months and 29%, respectively. The association between longer survival and positive delayed-type hypersensitivity to WT1 peptide was statistically significant, and longer survivors featured a higher frequency of memory-phenotype WT1-specific cytotoxic T lymphocytes both before and after treatment. WT1 vaccine in combination with gemcitabine was well tolerated for patients with advanced pancreatic cancer. Delayed-type hypersensitivity-positivity to WT1 peptide and a higher frequency of memory-phenotype WT1-specific cytotoxic T lymphocytes could be useful prognostic markers for survival in the combination therapy with gemcitabine and WT1 vaccine. Further clinical investigation is warranted to determine the effectiveness of this combination therapy.

Phase 1b, multicenter, single blinded, placebo-controlled, sequential dose escalation study to assess the safety and tolerability of topically applied AG013 in subjects with locally advanced head and neck cancer receiving induction chemotherapy.

BACKGROUND: Oral mucositis (OM) is a significant toxicity of induction chemotherapy for locally advanced head and neck cancer (LAHNC). The safety and tolerability of AG013, an oral rinse containing recombinant Lactococcus lactis secreting mucosal protectant human trefoil factor 1 (hTFF1), was evaluated in a phase 1b study in LAHNC subjects who received induction with cisplatin, 5-fluorouracil, with or without docetaxel. Preliminary efficacy data were also obtained. METHODS: A total of 25 of 52 LAHNC subjects who were followed during induction cycle 1 developed ulcerative oral mucositis (UOM; World Health Organization grade > 2) and were randomized to AG013:placebo (5:2 ratio) for cycle 2. Dosing schedules of 1, 3, or 6 times daily were evaluated (2 × 10(11) , 6 × 10(11) , and 1.2 × 10(12) colony forming units per day, respectively). OM was evaluated daily from cycle 2, day 1 through 14, using World Health Organization criteria. Pharmacokinetic assessment was also conducted. RESULTS: AG013 bacteria were not detected in blood. Oral live AG013 bacterial and hTFF1 levels in saliva and oral mucosa were equivalent among treatment groups. The most frequently occurring adverse events were nausea, oral pain, fatigue, diarrhea, and mucosal inflammation. Only 12% (3 of 25 adverse events), mainly nausea, were attributed to the investigational medicinal product: AG013 or placebo. Efficacy analysis showed a 35% reduction in percentage of days with UOM in AG013-subjects versus placebo. All placebo subjects experienced ≥ 2 days of UOM, whereas 29% of AG013 subjects had UOM for 0 or 1 day. AG013 use resulted in fewer unscheduled office and emergency room visits. No differences were noted in mouth and throat soreness, opioid use, or gastrostomy tube placement. CONCLUSIONS: AG013 was safe and well tolerated. Preliminary efficacy data support further study.

Netrin-1 protects against L-Arginine-induced acute pancreatitis in mice.

Acute pancreatitis (AP) is a common inflammatory disease mediated by damage to acinar cells and subsequent pancreatic inflammation with infiltration of leukocytes. The neuronal guidance protein, netrin-1, has been shown to control leukocyte trafficking and modulate inflammatory responses in several inflammation-based diseases. The present study was aimed toward investigating the effects of netrin-1 in an in vivo model of AP in mice. AP was induced in C57BL/6 mice by administration of two intraperitoneal injections of L-Arginine (4 g/kg). Mice were treated with recombinant mouse netrin-1 at a dose of 1 µg/mouse or vehicle (0.1% BSA) intravenously through the tail vein immediately after the second injection of L-Arginine, and every 24 h thereafter. Mice were sacrificed at several time intervals from 0 to 96 h after the induction of pancreatitis. Blood and tissue samples of pancreas and lung were collected and processed to determine the severity of pancreatitis biochemically and histologically. Immunohistochemical staining demonstrated that netrin-1 was mainly expressed in the islet cells of the normal pancreas and the AP model pancreas, and the pancreatic expression of netrin-1 was down-regulated at both the mRNA and protein levels during the course of AP. Exogenous netrin-1 administration significantly reduced plasma amylase levels, myeloperoxidase activity, pro-inflammatory cytokine production, and pancreas and lung tissue damages. Furthermore, netrin-1 administration did not cause significant inhibition of nuclear factor-kappa B activation in the pancreas of L-Arginine-induced AP. In conclusion, our novel data suggest that netrin-1 is capable of improving damage of pancreas and lung, and exerting anti-inflammatory effects in mice with severe acute pancreatitis. Thus, our results indicate that netrin-1 may constitute a novel target in the management of AP.

Phase I clinical trial of systemically administered TUSC2(FUS1)-nanoparticles mediating functional gene transfer in humans.

BACKGROUND: Tumor suppressor gene TUSC2/FUS1 (TUSC2) is frequently inactivated early in lung cancer development. TUSC2 mediates apoptosis in cancer cells but not normal cells by upregulation of the intrinsic apoptotic pathway. No drug strategies currently exist targeting loss-of-function genetic abnormalities. We report the first in-human systemic gene therapy clinical trial of tumor suppressor gene TUSC2. METHODS: Patients with recurrent and/or metastatic lung cancer previously treated with platinum-based chemotherapy were treated with escalating doses of intravenous N-[1-(2,3-dioleoyloxy)propyl]-N,N,N-trimethylammonium chloride (DOTAP):cholesterol nanoparticles encapsulating a TUSC2 expression plasmid (DOTAP:chol-TUSC2) every 3 weeks. RESULTS: Thirty-one patients were treated at 6 dose levels (range 0.01 to 0.09 milligrams per kilogram). The MTD was determined to be 0.06 mg/kg. Five patients achieved stable disease (2.6-10.8 months, including 2 minor responses). One patient had a metabolic response on positron emission tomography (PET) imaging. RT-PCR analysis detected TUSC2 plasmid expression in 7 of 8 post-treatment tumor specimens but not in pretreatment specimens and peripheral blood lymphocyte controls. Proximity ligation assay, performed on paired biopsies from 3 patients, demonstrated low background TUSC2 protein staining in pretreatment tissues compared with intense (10-25 fold increase) TUSC2 protein staining in post-treatment tissues. RT-PCR gene expression profiling analysis of apoptotic pathway genes in two patients with high post-treatment levels of TUSC2 mRNA and protein showed significant post-treatment changes in the intrinsic apoptotic pathway. Twenty-nine genes of the 82 tested in the apoptosis array were identified by Igenuity Pathway Analysis to be significantly altered post-treatment in both patients (Pearson correlation coefficient 0.519; p<0.01). CONCLUSIONS: DOTAP:chol-TUSC2 can be safely administered intravenously in lung cancer patients and results in uptake of the gene by human primary and metastatic tumors, transgene and gene product expression, specific alterations in TUSC2-regulated pathways, and anti-tumor effects (to our knowledge for the first time for systemic DOTAP:cholesterol nanoparticle gene therapy). TRIAL REGISTRATION: ClinicalTrials.gov NCT00059605.

Netrin-1 simultaneously suppresses corneal inflammation and neovascularization.

PURPOSE: To investigate the effect of netrin-1 on alkali burn-induced corneal inflammation and neovascularization. METHODS: The expression of netrin-1 and its receptors UNC5A, UNC5B, UNC5C, UNC5D, adenosine 2b receptor (A2BAR), deleted in colorectal cancer (DCC), and neogenin in normal and alkali-burned rat cornea were determined by RT-PCR and/or Western blot analysis, or immunostaining. Topical netrin-1 protein was applied to treat rat corneal alkali-burn injury for 14 consecutive days, started right after the injury or 10 days postinjury. Corneal inflammation and neovascularization were observed under slit lamp microscope. The apoptosis of corneal cells was determined by terminal deoxynucleotidyl transferase-mediated nick end labeling assay. Corneal inflammatory cell infiltration was evaluated by immunostaining of anti-PMN and anti-ED1 antibodies. The expression of epidermal growth factor (EGF), vascular epidermal growth factor (VEGF), and pigment epithelium-derived factor (PEDF) in rat cornea was determined by Western blot analysis. RESULTS: Netrin-1 and its receptor UNC5B were expressed in normal rat corneal epithelium and stromal cells, and their expression decreased after corneal alkali burn. Exogenous netrin-1 administered on rat ocular surfaces resolved alkali burn-induced corneal inflammation, and also suppressed corneal neovascularization. Furthermore, netrin-1 could reverse neovascularization in alkali-burned cornea. The authors found that netrin-1 executed the functions through various mechanisms, including upregulating EGF expression, accelerating epithelial wound healing, inhibiting neutrophil and macrophage infiltration, reducing corneal cell apoptosis, and restoring the equilibrium of VEGF and PEDF in the wounded cornea. CONCLUSIONS: Netrin-1 could dampen inflammation, inhibit, and reverse neovascularization in alkali-burned cornea.

Neuronal guidance molecule netrin-1 attenuates inflammatory cell trafficking during acute experimental colitis.

BACKGROUND: Inflammatory bowel diseases, encompassing Crohn's disease and ulcerative colitis, are characterised by persistent leucocyte tissue infiltration leading to perpetuation of an inappropriate inflammatory cascade. The neuronal guidance molecule netrin-1 has recently been implicated in the orchestration of leucocyte trafficking during acute inflammation. We therefore hypothesised that netrin-1 could modulate leucocyte infiltration and disease activity in a model of inflammatory bowel disease. DESIGN: DSS-colitis was performed in mice with partial genetic netrin-1 deficiency (Ntn-1(+/-) mice) or wild-type mice treated with exogenous netrin-1 via osmotic pump to examine the role of endogenous and therapeutically administered netrin-1. These studies were supported by in vitro models of transepithelial migration and intestinal epithelial barrier function. RESULTS: Consistent with our hypothesis, we observed induction of netrin-1 during intestinal inflammation in vitro or in mice exposed to experimental colitis. Moreover, mice with partial netrin-1 deficiency demonstrated an exacerbated course of DSS-colitis compared to littermate controls, with enhanced weight loss and colonic shortening. Conversely, mice treated with exogenous mouse netrin-1 experienced attenuated disease severity. Importantly, permeability studies and quantitative assessment of apoptosis reveal that netrin-1 signalling events do not alter mucosal permeability or intestinal epithelial cell apoptosis. In vivo studies of leucocyte transmigration demonstrate suppression of neutrophil trafficking as a key function mediated by endogenous or exogenously administered netrin-1. Finally, genetic studies implicate the A2B adenosine receptor in netrin-1-mediated protection during DSS-colitis. CONCLUSIONS: The present study identifies a previously unrecognised role for netrin-1 in attenuating experimental colitis through limitation of neutrophil trafficking.

Kisspeptin-10 is a potent stimulator of LH and increases pulse frequency in men.

CONTEXT: Kisspeptins stimulate GnRH and thus gonadotropin secretion. Kisspeptin-10 is the minimal kisspeptin sequence with full intrinsic bioactivity, but it has not been studied in man. OBJECTIVE: We investigated our hypothesis that kisspeptin-10 increases GnRH and thus LH pulse frequency. DESIGN AND PARTICIPANTS: The dose response of kisspeptin-10 was investigated by administering iv bolus doses (0.01-3.0 µg/kg) and vehicle to healthy men. Effects on LH pulse frequency and size were determined by deconvolution analysis during infusion of kisspeptin-10 for up to 22.5 h. RESULTS: Intravenous bolus kisspeptin-10 resulted in a rapid and dose-dependent rise in serum LH concentration, with maximal stimulation at 1 µg/kg (4.1 ± 0.4 to 12.4 ± 1.7 IU/liter at 30 min, P < 0.001, n = 6). Administration of 3 µg/kg elicited a reduced response vs. 1 µg/kg (P < 0.05). Infusion of kisspeptin-10 at 4 µg/kg · h for 22.5 h elicited an increase in LH from a mean of 5.4 ± 0.7 to 20.8 ± 4.9 IU/liter (n = 4; P < 0.05) and serum testosterone increased from 16.6 ± 2.4 to 24.0 ± 2.5 nmol/liter (P < 0.001). LH pulses were obscured at this high rate of secretion, but a lower dose infusion of kisspeptin-10 (1.5 µg/kg · h) increased mean LH from 5.2 ± 0.8 to 14.1 ± 1.7 IU/liter (n = 4; P < 0.01) and increased LH pulse frequency from 0.7 ± 0.1 to 1.0 ± 0.2 pulses/h (P < 0.05) and secretory burst mass from 3.9 ± 0.4 to 12.8 ± 2.6 IU/liter (P < 0.05). CONCLUSIONS: Kisspeptin-10 boluses potently evoke LH secretion in men, and continuous infusion increases testosterone, LH pulse frequency, and pulse size. Kisspeptin analogues have therapeutic potential as regulators of LH and thus testosterone secretion.

Overexpression of netrin-1 improves neurological outcomes in mice following transient middle cerebral artery occlusion.

Netrin-1 (NT-1) is one of the axon-guiding molecules that are critical for neuronal development. Because of its structural homology to the endothelial mitogens, NT-1 may have similar effects on vascular network formation. NT-1 was shown to be able to stimulate the proliferation and migration of human cerebral endothelial cells in vitro and also promote focal neovascularization in adult brain in vivo. In the present study, we reported the delivery of NT-1 using an adeno-associated virus (AAV) vector (AAV-NT-1) into mouse brain followed by transient middle cerebral artery occlusion (tMCAO). We found that AAV vectors did not elicit a detectable inflammatory response, cell loss or neuronal damage after brain transduction. The level of NT-1 was increased in the AAV-NT-1-transduced tMCAO mice compared with the control mice. Furthermore, the neurobehavioral outcomes were significantly improved in AAV-NT-1-transduced mice compared with the control animals (P<0.05) 7 days after tMCAO. Our data suggests that NT-1 plays a neuronal function recovery role in ischemic brain and that NT-1 gene transfer might present a valuable approach to treat brain ischemic disorders.

Centrally injected kisspeptin reduces food intake by increasing meal intervals in mice.

Kisspeptin is distributed not only in brain areas for regulating reproduction but also in nuclei involved in feeding control. Whether kisspeptin alters food intake is unknown in mice. We examined how kisspeptin-10 influences feeding after intracerebroventricular injection in mice using automated monitoring. Kisspeptin-10 (0.3, 1, and 3 µg/mouse) dose-dependently inhibited the feeding response to an overnight fast by 50, 95, and 90% respectively, during the 2-3 h period postinjection. The 1µg/mouse dose reduced the 4-h cumulative food intake by 28% whereas intraperitoneal injection (10 µg/mouse) did not. The decreased 4-h food intake was due to reduced meal frequency (-45%/4 h), whereas meal size and gastric emptying were not altered. These data suggest that kisspeptin may be a negative central regulator of feeding by increasing satiety.

HIV-Tat-mediated delivery of an LPTS functional fragment inhibits telomerase activity and tumorigenicity of hepatoma cells.

BACKGROUND & AIMS: Human liver-related putative tumor suppressor (LPTS) is a gene that encodes a telomerase inhibitory protein that is similar to human Pin2/TRF1-interacting protein. The LPTS protein binds directly to the telomerase catalytic subunit (human telomerase reverse transcriptase) and suppresses telomerase activity. Telomere maintenance and telomerase activity are required for long-term proliferation of cancer cells, so LPTS might be used in anticancer strategies. METHODS: The carboxy-terminal (functional) fragment of LPTS was fused to the transactivator of transcription of human immunodeficiency virus (Tat)-an 11-amino acid peptide that translocates across the cell membrane; the TAT-fused C-terminal of LPTS (TAT-LPTS-LC) was purified and transduced into cells. Telomerase activity was identified by using the telomeric repeat amplification protocol. The effects of the TAT-LPTS-LC protein on cell proliferation and death were evaluated by colorimetric tetrazolium salt and flow cytometry analyses. Tumor growth was analyzed in nude mice. RESULTS: The purified TAT-LPTS-LC protein was efficiently delivered into the cells, where it suppressed telomerase activity and shortened telomere length. TAT-LPTS-LC inhibited proliferation of telomerase-positive hepatocellular carcinoma BEL-7404 and hepatoblastoma HepG2cells and induced their death; however, it had no effect on telomerase-negative liver cell line L02 and osteosarcoma cell line Saos-2. In mice, tumor formations by BEL-7404 cells were suppressed by TAT-LPTS-LC treatments. CONCLUSIONS: Transduction of hepatoma cells with a fusion protein that contains the C-terminal, functional fragment of LPTS and human immunodeficiency virus Tat (TAT-LPTS-LC) causes telomere shortening, limits proliferation, and inhibits growth of tumors from these cells in mice. TAT-LPTS-LC inhibits telomerase activity and might be developed as an anticancer agent.

Study on the effect of peripheral kisspeptin administration on basal and glucose-induced insulin secretion under fed and fasting conditions in the adult male rhesus monkey (Macaca mulatta).

Kisspeptin (KP)-Kiss1r, a ligand-receptor pair, has recently been implicated as a pivotal regulator of the neuroendocrine reproductive axis. KISS1 (encoding KP) as well as KISS1R (encoding receptor for KP) are expressed in several peripheral tissues including the pancreas. But the specific role of KP in the physiology of pancreas is still incompletely deciphered. This study was designed to examine the effect of peripheral KP administration on basal and glucose-induced plasma insulin (an important pancreatic hormone) secretion under fed and fasting conditions in the adult male rhesus monkey. A set of 4 chair-restraint habituated intact adult male rhesus monkeys were assigned to receive intravenous bolus administration of human kisspeptin-10 (KP10, 50 µg), and vehicle (1 ml) in normal fed and fasting conditions without or with glucose infusions. Plasma concentrations of insulin were measured by using a specific IRMA. Glucose infusion significantly stimulated plasma insulin levels (p<0.005). Vehicle administration did not affect both basal and glucose stimulated insulin in fed as well as in fasting condition. KP10 administration had no effect on the basal insulin levels in both fed and fasting as compared to pretreatment or vehicle treatment levels, while it significantly heightened glucose stimulated insulin levels (p<0.05) in both fed and fasted monkeys. The present results show that KP administration does not affect the basal secretion of insulin under both fed and fasting condition while potentiated the glucose-induced insulin levels in the adult male rhesus monkey. Therefore, these findings suggest a potential role of KP in the physiology of pancreas.

Intraperitoneal kisspeptin-10 administration induces dose-dependent degenerative changes in maturing rat testes.

AIMS: Kisspeptin, a peptide secreted by hypothalamic neurons, is a critical regulator of reproduction and puberty but its role in the regulation of gonadal maturation in sexually immature males is elusive. The present study investigated the effects of 12 days of pulsatile kisspeptin administration on gonadotropins and testosterone release and maturation of immature male gonads. MAIN METHODS: Kisspeptin-10 was administered intraperitoneally at different dosage concentrations (1 µg, 1 ng, and 10 pg) to 5 weeks old prepubertal male rats, twice daily for 12 days. Plasma LH, FSH and testosterone concentrations were measured through competitive-binding radioimmunoassay. Spermatogenesis was studied mainly at stage VII of the spermatogenic cycle through light and electron microscopy. KEY FINDINGS: At the end of the treatments plasma LH and testosterone concentrations were reduced significantly at 1ng and 1µg kisspeptin doses (P<0.05; P<0.01). Type A spermatogonia, preleptotene spermatocytes, pachytene spermatocytes, step 7 spermatids, elongated spermatids and daily sperm production decreased significantly (P<0.05). Sertoli cell efficiency and total support capacity of Sertoli cells were reduced at all doses (P<0.05). Meiotic index decreased (P<0.05) at 1 µg dose only, whereas coefficient of mitosis increased at 1 ng and 1 µg (P<0.01) kisspeptin doses. Histologically, degeneration of seminiferous tubules was evident showing tubular necrosis, multinucleated giant cell formation, intratubular vacuolization, widened lumen and deshaped germ cells. Marked ultrastructural changes characterized by thin basal laminae, enlarged intratubular spaces, abnormal acrosome and disrupted germ cells were noticeable. SIGNIFICANCE: In conclusion long-term kisspeptin-10 administration negatively regulates gonadal maturation in prepubertal testes.