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Reporter gene imaging (RGI) is described as the methodology that involves imaging of the encoding proteins that can be used as surrogate markers when fused with regulatory regions of the gene of interest. It provides a means to indirectly monitor molecular processes that are implicated in the pathophysiology of several diseases. The modalities utilized in RGI include MRI, PET, SPECT, as well as optical imaging modalities, such as bioluminescence and fluorescence. RGI provides a highly specific way to qualitatively and quantitatively assess cell targeting, transfection, protein expression and other intracellular processes, which are valuable for pharmacodynamic and pharmacokinetic assessment of cellular, gene and oncolytic viral therapeutics.

INTRODUCTION: A possible target for stroke management is modulation of neuroinflammation. Evidence suggests that food components may exert anti-inflammatory properties and thus may reduce stroke-induced brain damage.AIM: To investigate the efficacy of a diet, containing anti-inflammatory ingredients, as treatment for focal ischemic brain damage induced by photothrombotic stroke in the somatosensory cortex of rats.RESULTS: Brain lesions were surrounded by strong astrogliosis on both day 7 and day 21 after stroke and were accompanied by a trend toward globally decreased glucose metabolism on day 7. The investigational diet applied 2 weeks before the ischemia did not affect astrocyte activation on day 7, but reduced it at day 21. The investigational diet applied immediately after the ischemia, increased astrocyte activation on day 7 and completely reversed this effect on day 21. Moreover, postischemic intervention increased glucose metabolism in somatosensory cortex ipsilateral to the lesion on day 7.CONCLUSION: This study reveals potentially beneficial effects of a diet containing elevated amounts of anti-inflammatory nutrients on the recovery from ischemic brain damage. Therefore, dietary intervention can be considered as an adjuvant therapy for recovery from this brain pathology.

Psychosocial stress is a risk factor for the development of depression. Recent evidence suggests that glial activation could contribute to the development of depressive-like behaviour. This study aimed to evaluate in vivo whether repeated social defeat (RSD) induces short- and long-term inflammatory and metabolic alterations in the brain through positron emission tomography (PET). Male Wistar rats ( n = 40) were exposed to RSD by dominant Long-Evans rats on five consecutive days. Behavioural and biochemical alterations were assessed at baseline, day 5/6 and day 24/25 after the RSD protocol. Glial activation (11C-PK11195 PET) and changes in brain metabolism (18F-FDG PET) were evaluated on day 6, 11 and 25 (short-term), and at 3 and 6 months (long-term). Defeated rats showed transient depressive- and anxiety-like behaviour, increased corticosterone and brain IL-1β levels, as well as glial activation and brain hypometabolism in the first month after RSD. During the third- and six-month follow-up, no between-group differences in any investigated parameter were found. Therefore, non-invasive PET imaging demonstrated that RSD induces transient glial activation and reduces brain glucose metabolism in rats. These imaging findings were associated with stress-induced behavioural changes and support the hypothesis that neuroinflammation could be a contributing factor in the development of depression.

Chimeric antigen receptor T cell therapy (CAR-T) has been rolled out as a new treatment for hematological malignancies. For solid tumor treatment, CAR-T has been disappointing so far. Challenges include the quantification of CAR-T trafficking, expansion and retention in tumors, activity at target sites, toxicities, and long-term CAR-T survival. Non-invasive serial in vivo imaging of CAR-T using reporter genes can address several of these challenges. For clinical use, a non-immunogenic reporter that is detectable with exquisite sensitivity by positron emission tomography (PET) using a clinically available non-toxic radiotracer would be beneficial. Here, we employed the human sodium iodide symporter to non-invasively quantify tumor retention of pan-ErbB family targeted CAR-T by PET. We generated and characterized traceable CAR T cells and examined potential negative effects of radionuclide reporter use. We applied our platform to two different triple-negative breast cancer (TNBC) models and unexpectedly observed pronounced differences in CAR-T tumor retention by PET/CT (computed tomography) and confirmed data ex vivo. CAR-T tumor retention inversely correlated with immune checkpoint expression in the TNBC models. Our platform enables highly sensitive non-invasive PET tracking of CAR-T thereby addressing a fundamental unmet need in CAR-T development and offering to provide missing information needed for future clinical CAR-T imaging., Graphical Abstract, CAR-T immunotherapy remains challenging in solid tumors, not least as quantitation of CAR-T in vivo distribution, activity, and fate remains elusive. Fruhwirth and colleagues developed and validated a platform for non-invasive in vivo CAR-T tracking by highly sensitive PET imaging and demonstrated its application in triple-negative breast cancer models. Beyond supporting preclinical CAR-T development, they provide a clinically compatible CAR-T monitoring tool.

Highlights • iPSC-derived hepatocyte-like cells (HLCs) rendered traceable in vivo. • Reproducible lentivirus-based gene transfer during the differentiation process. • Protocol and reporter expression did not negatively impact on HLC maturation. • Proof-of-principle shown for whole-body SPECT/CT-afforded HLC in vivo tracking., Primary hepatocyte transplantation (HTx) is a safe cell therapy for patients with liver disease, but wider application is circumvented by poor cell engraftment due to limitations in hepatocyte quality and transplantation strategies. Hepatocyte-like cells (HLCs) derived from human induced pluripotent stem cells (hiPSC) are considered a promising alternative but also require optimisation of transplantation and are often transplanted prior to full maturation. Whole-body in vivo imaging would be highly beneficial to assess engraftment non-invasively and monitor the transplanted cells in the short and long-term. Here we report a lentiviral transduction approach designed to engineer hiPSC-derived HLCs during differentiation. This strategy resulted in the successful production of sodium iodide symporter (NIS)-expressing HLCs that were functionally characterised, transplanted into mice, and subsequently imaged using radionuclide tomography., Graphical abstract Image, graphical abstract

Neuroinflammation is a common phenomenon in the pathology of many brain diseases. In this paper we explore whether selected vitamins and fatty acids known to modulate inflammation exert an effect on microglia, the key cell type involved in neuroinflammation. Previously these nutrients have been shown to exert anti-inflammatory properties acting on specific inflammatory pathways. We hypothesized that combining nutrients acting on converging anti-inflammatory pathways may lead to enhanced anti-inflammatory properties as compared to the action of a single nutrient. In this study, we investigated the anti-inflammatory effect of combinations of nutrients based on the ability to inhibit the LPS-induced release of nitric oxide and interleukin-6 from BV-2 cells. Results show that omega-3 fatty acids, vitamins A and D can individually reduce the LPS-induced secretion of the pro-inflammatory cytokines by By 2 cells. Moreover, we show that vitamins A, D and omega-3 fatty acids (docosahexaenoic and eicosapentaenoic) at concentrations where they individually had little effect, significantly reduced the secretion of the inflammatory mediator, nitric oxide, when they were combined. The conclusion of this study is that combining different nutrients acting on convergent anti-inflammatory pathways may result in an increased anti-inflammatory efficacy. (C) 2016 Elsevier Ltd. All rights reserved.

Neuroinflammation has been implicated in the pathology of various psychiatric and neurodegenerative disorders. Accumulating evidence suggests that food components can modulate inflammatory processes, and therefore it could be hypothesized that such nutrients might exhibit therapeutic efficacy against these brain diseases. Rice bran is often discarded as a waste product, although it contains a wide range of potentially useful substances. Several rice fiber components from rice bran have been described as having antiinflammatory properties. This review summarizes the evidence supporting a modulatory effect of rice fiber components on symptoms in several animal models for neuroinflammation. In vitro studies on immune cells and in vivo studies on nutritional intervention in animal models of central and peripheral inflammation are discussed in the context of the potential use of rice fiber components for prevention and treatment of brain diseases in which neuroinflammation is involved.

Microscopy and medical imaging are related in their exploitation of electromagnetic waves, but were developed to satisfy differing needs, namely to observe small objects or to look inside subjects/objects, respectively. Together, these techniques can help elucidate complex biological processes and better understand health and disease. A current major challenge is to delineate mechanisms governing cell migration and tissue invasion in organismal development, the immune system and in human diseases such as cancer where the spatiotemporal tracking of small cell numbers in live animal models is extremely challenging. Multi-modal multi-scale in vivo cell tracking integrates medical and optical imaging. Fuelled by basic research in cancer biology and cell-based therapeutics, it has been enabled by technological advances providing enhanced resolution, sensitivity and multiplexing capabilities. Here, we review which imaging modalities have been successfully used for in vivo cell tracking and how this challenging task has benefitted from combining macroscopic with microscopic techniques.

Ulcerative colitis (UC) is a chronic inflammatory disease of the colon that affects an increasing number of patients. High comorbidity is observed between UC and other diseases in which inflammation may be involved, including brain diseases such as cognitive impairment, mental disorders, anxiety, and depression. To investigate the increased occurrence of these brain diseases in patients with UC, non-invasive methods for monitoring peripheral and central inflammation could be applied. Therefore, the goal of this study is to assess the feasibility of monitoring gut and brain inflammation in a rat model of chemically induced colitis by positron emission tomography (PET) with [C-11]PBR28, a tracer targeting the translocator protein (TSPO), which is upregulated when microglia and macrophages are activated.Colitis was induced in rats by intra-rectal injection of 2,4,6-trinitrobenzenesulfonic acid (TNBS). Rats with colitis and healthy control animals were subjected to [C-11]PBR28 PET of the abdomen followed by ex vivo biodistribution in order to assess whether inflammation in the gut could be detected. Another group of rats with colitis underwent repetitive [C-11]PBR28 PET imaging of the brain to investigate the development of neuroinflammation.Eleven days after TNBS injection, ex vivo biodistribution studies demonstrated increased [C-11]PBR28 uptake in the inflamed cecum and colon of rats with colitis as compared to healthy controls, whereas PET imaging did not show any difference between groups at any time. Similarly, repetitive PET imaging of the brain did not reveal any neuroinflammation induced by the TNBS administration in the colon. In contrast, significantly increased [C-11]PBR28 uptake in cerebellum could be detected in ex vivo biodistribution studies on day 11.Inflammation in both the gut and the brain of rats with chemically induced colitis was observed by ex vivo biodistribution. However, these effects could not be detected by [C-11]PBR28 PET imaging in our colitis model, which is likely due to spill-over effects and insufficient resolution of the PET camera.

Microglial-neuronal interactions are essential for brain physiopathology. In this framework, recent data have changed the concept of microglia from essentially macrophagic cells to crucial elements in maintaining neuronal homeostasis and function through the release of neuroprotective molecules. Using proteomic analysis, here we identify copper-zinc superoxide dismutase (SOD1) as a protein produced and released by cultured rat primary microglia. Evidence for a neuroprotective role of microglia-derived SOD1 resulted from experiments in which primary cerebellar granule neurons (CGNs) were exposed to the dopaminergic toxin 6-hydroxydopamine (6-OHDA). Microglial conditioned medium, in which SOD1 had accumulated, protected CGNs from degeneration, and neuroprotection was abrogated by SOD1 inhibitors. These effects were replicated when exogenous SOD1 was added to a nonconditioned medium. SOD1 neuroprotective action was mediated by increased cell calcium from an external source. Further experiments demonstrated the specificity of SOD1 neuroprotection against 6-OHDA compared to other types of neurotoxic challenges. SOD1, constitutively produced and released by microglia through a lysosomal secretory pathway, is identified here for the first time as an essential component of neuroprotection mediated by microglia. This novel information is relevant to stimulating further studies of microglia-mediated neuroprotection in in vivo models of neurodegenerative diseases.

Valproic acid (VPA), a long-standing anti-epileptic and anti-manic drug, exerts multiple actions in the nervous system through various molecular mechanisms. Neuroprotective properties have been attributed to VPA in different models of neurodegeneration, but contrasting results on its improvement of learning and memory have been reported in non-pathologic conditions. In the present study, we have tested on a hippocampal-dependent learning test, the contextual fear conditioning, the effect of chronic VPA administration through alimentary supplementation that allows relatively steady concentrations to be reached by a drug otherwise very rapidly eliminated in rodents. Contextual fear memory was significantly impaired in rats chronically treated with VPA for 4 weeks. To understand the cellular and molecular correlates of this amnesic effect with particular regard to hippocampus, we addressed three putatively memory-related targets of VPA action in this brain area, obtaining the following main results: i) chronic VPA promoted an increase of post-translational modifications of histone H3 (acetylation and phosphorylation) known to favor gene transcription; ii) adult neurogenesis in the dentate gyrus, which has been controversially reported to be affected by VPA, was unchanged; and iii) GSK-3β, a kinase playing a key role in hippocampal plasticity, as well as in learning and memory, was dysregulated by VPA treatment. These results point at GSK-3β dysregulation in the hippocampus as an important parameter in the amnesic effect of VPA. The VPA amnesic effect in the animal model here reported is also supported by some observations in patients and, therefore, it should be taken into account and monitored in VPA-based therapies., The present work was supported from research grants of the University of Bologna to B.M. and A.C.