Evidence is growing that the gut microbiota modulates the host response to chemotherapeutic drugs, with three main clinical outcomes: facilitation of drug efficacy; abrogation and compromise of ...anticancer effects; and mediation of toxicity. The implication is that gut microbiota are critical to the development of personalized cancer treatment strategies and, therefore, a greater insight into prokaryotic co-metabolism of chemotherapeutic drugs is now required. This thinking is based on evidence from human, animal and in vitro studies that gut bacteria are intimately linked to the pharmacological effects of chemotherapies (5-fluorouracil, cyclophosphamide, irinotecan, oxaliplatin, gemcitabine, methotrexate) and novel targeted immunotherapies such as anti-PD-L1 and anti-CLTA-4 therapies. The gut microbiota modulate these agents through key mechanisms, structured as the 'TIMER' mechanistic framework: Translocation, Immunomodulation, Metabolism, Enzymatic degradation, and Reduced diversity and ecological variation. The gut microbiota can now, therefore, be targeted to improve efficacy and reduce the toxicity of current chemotherapy agents. In this Review, we outline the implications of pharmacomicrobiomics in cancer therapeutics and define how the microbiota might be modified in clinical practice to improve efficacy and reduce the toxic burden of these compounds.
Improved delivery of adeno-associated virus (AAV) vectors to the CNS will greatly enhance their clinical utility. Selection of AAV9 variants in a mouse model led to the isolation of a capsid called ...PHP.B, which resulted in remarkable transduction of the CNS following intravenous infusion. However, we now show here that this enhanced CNS tropism is restricted to the model in which it was selected, i.e., a Cre transgenic mouse in a C57BL/6J background, and was not found in nonhuman primates or the other commonly used mouse strain BALB/cJ. We also report the potential for serious acute toxicity in NHP after systemic administration of high dose of AAV.
Recombinant adeno-associated viruses (AAVs) have unique gene-transfer properties that speak to their potential as carriers for gene therapy or vaccine applications. However, the presence of ...neutralizing antibodies to AAV as a result of previous exposure can significantly limit effective gene transfer. In this study, we obtained 888 human serum samples from healthy volunteers in 10 countries around the world. Samples were assayed for neutralizing antibodies to AAV1, AAV2, AAV7, and AAV8, as well as to a novel, structurally distinctAAVvector, rh32.33, in an in vitro transduction inhibition assay. Our data revealed that neutralizing antibodies to AAV2 were the most prevalent antibodies in all regions, followed by antibodies to AAV1. The seroprevalences of antibodies to AAV7 and to AAV8 were lower than that for antibodies to AAV1, and neutralization of AAVrh32.33 was only rarely detected. Our data also indicate a strong linkage of seroreactivity between apparently distinct serotypes that has not been predicted previously in animal models.
In humans, the cGAS-STING immunity pathway signals in response to cytosolic DNA via 2′,3′ cGAMP, a cyclic dinucleotide (CDN) second messenger containing mixed 2′–5′ and 3′–5′ phosphodiester bonds. ...Prokaryotes also produce CDNs, but these are exclusively 3′ linked, and thus the evolutionary origins of human 2′,3′ cGAMP signaling are unknown. Here we illuminate the ancient origins of human cGAMP signaling by discovery of a functional cGAS-STING pathway in Nematostella vectensis, an anemone species >500 million years diverged from humans. Anemone cGAS appears to produce a 3′,3′ CDN that anemone STING recognizes through nucleobase-specific contacts not observed in human STING. Nevertheless, anemone STING binds mixed-linkage 2′,3′ cGAMP indistinguishably from human STING, trapping a unique structural conformation not induced by 3′,3′ CDNs. These results reveal that human mixed-linkage cGAMP achieves universal signaling by exploiting a deeply conserved STING conformational intermediate, providing critical insight for therapeutic targeting of the STING pathway.
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•Binding of CDNs is an evolutionarily ancient STING function, predating interferons•cGAS-STING function is conserved in anemone, >500 million years diverged from humans•Anemone cGAS produces a canonical 3′,3′ linked CDN similar to those in bacteria•Vertebrate 2′,3′ cGAMP signaling exploits a deeply conserved STING conformation
Kranzusch and Wilson et al. use structural and biochemical approaches to characterize human and anemone cGAS-STING immune pathways, demonstrating that the product of human cGAS is a potent STING activator because it targets an ancient, conserved, intermediate conformation of STING.
A major challenge to advance lipid nanoparticles (LNPs) for RNA therapeutics is the development of formulations that can be produced reliably across the various scales of drug development. ...Microfluidics can generate LNPs with precisely defined properties, but have been limited by challenges in scaling throughput. To address this challenge, we present a scalable, parallelized microfluidic device (PMD) that incorporates an array of 128 mixing channels that operate simultaneously. The PMD achieves a >100× production rate compared to single microfluidic channels, without sacrificing desirable LNP physical properties and potency typical of microfluidic-generated LNPs. In mice, we show superior delivery of LNPs encapsulating either Factor VII siRNA or luciferase-encoding mRNA generated using a PMD compared to conventional mixing, with a 4-fold increase in hepatic gene silencing and 5-fold increase in luciferase expression, respectively. These results suggest that this PMD can generate scalable and reproducible LNP formulations needed for emerging clinical applications, including RNA therapeutics and vaccines.
It has been 9 years since Mr. Jesse Gelsinger died from complications of vector administration in a liver gene therapy trial of research subjects with a deficiency of ornithine transcarbamylase ...(OTCD). This study was performed at the Institute for Human Gene Therapy of the University of Pennsylvania (Penn) which I directed. His tragic death provoked a series of events that had implications beyond those directly involved in the clinical trial.
The events surrounding the death of this research subject have been the topic of much coverage and commentary in the popular press. The goal of this article is to share with you my reflections on the OTCD gene therapy trial and lessons that I have learned which may be of value to others engaged in various aspects of translational medicine.
Humoral Immune Response to AAV Calcedo, Roberto; Wilson, James M
Frontiers in immunology,
10/2013, Volume:
4
Journal Article
Peer reviewed
Open access
Adeno-associated virus (AAV) is a member of the family Parvoviridae that has been widely used as a vector for gene therapy because of its safety profile, its ability to transduce both dividing and ...non-dividing cells, and its low immunogenicity. AAV has been detected in many different tissues of several animal species but has not been associated with any disease. As a result of natural infections, antibodies to AAV can be found in many animals including humans. It has been shown that pre-existing AAV antibodies can modulate the safety and efficacy of AAV vector-mediated gene therapy by blocking vector transduction or by redirecting distribution of AAV vectors to tissues other than the target organ. This review will summarize antibody responses against natural AAV infections, as well as AAV gene therapy vectors and their impact in the clinical development of AAV vectors for gene therapy. We will also review and discuss the various methods used for AAV antibody detection and strategies to overcome neutralizing antibodies in AAV-mediated gene therapy.
Intra-arterial administration of an adenovirus serotype 5 (Ad5) vector in a gene therapy trial caused lethal, systemic inflammation in subject 019 with ornithine transcarbamylase deficiency. This ...unanticipated inflammatory response was absent in another subject receiving the same vector dose and in 16 subjects receiving lower vector doses. We hypothesized that an immune memory to a previous natural adenovirus infection enhanced the immune response to high-dose systemic Ad5 vector, causing the exaggerated immune response in subject 019. To investigate this, we found that rabbit polyclonal sera to Ad5 and pooled human immunoglobulin (Ig) inhibited Ad5 vector transduction of non-immune cells in vitro, but enhanced transduction and activation of human dendritic cells (DCs). Sera from approximately 7% of normal human subjects and 50% of patients treated topically with Ad5 vectors enhanced Ad5 transduction and activation of DCs, apparently from formation of Ig-Ad5 immune complexes and binding to DCs through FcγR. Subject 019’s blood substantially increased Ad5-vector activation of human DC primary cultures at levels exceeding those from normal subjects. Although this study is based on one event in a single subject, the results implicate a pre-existing humoral immune response to Ad5 in the lethal systemic inflammatory response that occurred in subject 019.
In order to understand the mechanism underlying a lethal systemic inflammation in an adenoviral vector gene therapy trial, we explored the hypothesis that immune memory to the vector may be a contributing factor. We show that an antibody to the vector capsid from a natural infection enhanced activation of antigen-presenting cells.
Each odorant receptor corresponds to a unique glomerulus in the brain. Projections from different glomeruli then converge in higher brain regions, but we do not understand the logic governing which ...glomeruli converge and which do not. Here, we use two-photon optogenetics to map glomerular connections onto neurons in the lateral horn, the region of the Drosophila brain that receives the majority of olfactory projections. We identify 39 morphological types of lateral horn neurons (LHNs) and show that different types receive input from different combinations of glomeruli. We find that different LHN types do not have independent inputs; rather, certain combinations of glomeruli converge onto many of the same LHNs and so are over-represented. Notably, many over-represented combinations are composed of glomeruli that prefer chemically dissimilar ligands whose co-occurrence indicates a behaviorally relevant “odor scene.” The pattern of glomerulus-LHN connections thus represents a prediction of what ligand combinations will be most salient.
•Lateral horn neurons (LHNs) divide into many distinctive morphology types•Same-type LHNs have similar but non-identical glomerular connectivity•Certain over-represented glomerular combinations wire onto multiple LHN types•Over-represented combinations unite glomeruli co-activated by salient odor scenes
Jeanne et al. use two-photon optogenetics to map connections from olfactory glomeruli onto lateral horn neurons in Drosophila. Certain combinations of glomeruli are over-represented. These are not similarly tuned glomeruli; rather, they are glomeruli whose co-activation signals a salient “odor scene.”
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