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On August 18, 2021, the American Society of Gene and Cell Therapy (ASGCT) hosted a virtual roundtable on adeno-associated virus (AAV) integration, featuring leading experts in preclinical and clinical AAV gene therapy, to further contextualize and understand this phenomenon. Recombinant AAV (rAAV) vectors are used to develop therapies for many conditions given their ability to transduce multiple cell types, resulting in long-term expression of transgenes. Although most rAAV DNA typically remains episomal, some rAAV DNA becomes integrated into genomic DNA at a low frequency, and rAAV insertional mutagenesis has been shown to lead to tumorigenesis in neonatal mice. Currently, the risk of rAAV-mediated oncogenesis in humans is theoretical because no confirmed genotoxic events have been reported to date. However, because insertional mutagenesis has been reported in a small number of murine studies, there is a need to characterize this genotoxicity to inform research, regulatory needs, and patient care. The purpose of this white paper is to review the evidence of rAAV-related host genome integration in animal models and possible risks of insertional mutagenesis in patients. In addition, technical considerations, regulatory guidance, and bioethics are discussed.

Small RNAs processed from transfer RNA are recognized to have regulatory functions distinct from protein synthesis. This rapidly advancing field has led to a constellation of transcript nomenclatures. Building upon the accepted tRNA naming system and linking tRNA-derived small RNAs to their molecular sources, we propose an improved nomenclature. Facilitated by the tDRnamer system, it will promote inter-study comparisons leveraging a biologically-rooted nomenclature for this emerging class of intriguing regulators.

BACKGROUND Gene therapy is a promising treatment for protein deficiency disorders such as hemophilia B. However, low tissue selectivity and efficacy are limitations of systemic vector delivery. The authors hypothesized that selective transfection of rat superficial inferior epigastric artery flaps could provide systemic delivery of coagulation factor IX, preventing the need for systemic vector administration. METHODS Minicircle DNA containing green fluorescent protein, firefly luciferase, and human coagulation factor IX were created. Vector constructs were validated by transfecting adipose-derived stromal cells isolated from Wistar rat superficial inferior epigastric artery flaps and evaluating transgene expression by fluorescence microscopy, bioluminescence, and enzyme-linked immunosorbent assay. Minicircle DNA luciferase (10 and 30 μg) was injected into murine (wild-type, C57/BL/6) inguinal fat pads (n = 3) and followed by in vivo bioluminescence imaging for 60 days. Wistar rat superficial inferior epigastric artery flaps were transfected with minicircle DNA human coagulation factor IX (n = 9) with plasma and tissue transgene expression measured by enzyme-linked immunosorbent assay at 2 and 4 weeks. RESULTS Transfected adipose-derived stromal cells expressed green fluorescent protein for 30 days, luciferase for 43 days, and human coagulation factor IX (21.9 ± 1.2 ng/ml) for 28 days in vitro. In vivo murine studies demonstrated dose-dependence between minicircle DNA delivery and protein expression. Ex vivo rat superficial inferior epigastric artery flap transfection with minicircle DNA human coagulation factor IX showed systemic transgene expression at 2 (266.6 ± 23.4 ng/ml) and 4 weeks (290.1 ± 17.1 ng/ml) compared to control tissue (p < 0.0001). CONCLUSIONS Rat superficial inferior epigastric artery flap transfection using minicircle DNA human coagulation factor IX resulted in systemic transgene detection, suggesting that selective flap or angiosome-based tissue transfection may be explored as a treatment for systemic protein deficiency disorders such as hemophilia B.

SummaryRecombinant adeno-associated viral vectors (rAAVs) are among the most commonly used vehicles for in vivo based gene therapies. However, it is hard to predict which AAV capsid will provide the most robust expression in human subjects due to the observed discordance in vector-mediated transduction between species. We used a primate specific capsid, AAV-LK03, and demonstrated that the limitation of this capsid towards transduction of mouse cells was unrelated to cell entry and nuclear transport but rather due to depleted histone H3 chemical modifications related to active transcription, namely H3K4me3 and H3K27ac, on the vector DNA itself. A single-amino acid insertion into the AAV-LK03 capsid enabled efficient transduction and the accumulation of active histone marks on the vector chromatin in mouse without compromising transduction efficiency in human cells. Our study suggests that the capsid protein itself is involved in determining the chromatin status of the vector genome, most likely during the process of uncoating. Programming viral chromatin states by capsid design may enable facile DNA transduction between vector and host species.

Adeno-associated virus (AAV) is one of the most commonly used vectors for gene therapy, and the applications for AAV-delivered therapies are numerous. However, the current state of technology is limited by the low efficiency with which most AAV vectors transduce skeletal muscle tissue. We demonstrate that vector efficiency can be enhanced by modifying the AAV capsid with a peptide that binds a receptor highly expressed in muscle tissue. When an insulin-mimetic peptide, S519, previously characterized for its high affinity to insulin receptor (IR), was inserted into the capsid, the AAV9 transduction efficiency of IR-expressing cell lines as well as differentiated primary human muscle cells was dramatically enhanced. This vector also exhibited efficient transduction of mouse muscle in vivo, resulting in up to 18-fold enhancement over AAV9. Owing to its superior transduction efficiency in skeletal muscle, we named this vector “enhanced AAV9” (eAAV9). We also found that the modification enhanced the transduction efficiency of several other AAV serotypes. Together, these data show that AAV transduction of skeletal muscle can be improved by targeting IR. They also show the broad utility of this modular strategy and suggest that it could also be applied to next-generation vectors that have yet to be engineered., Graphical Abstract, Skeletal muscle may be used as a “factory” for the production of therapeutic proteins for systemic distribution. In this study, Choe and colleagues detail an approach for enhanced gene delivery to skeletal muscle using AAV vectors modified to utilize insulin receptor, which is highly expressed on differentiated muscle.

Tandem repeats are proposed to contribute to human-specific traits, and more than 40 tandem repeat expansions are known to cause neurological disease. Here, we characterize a human-specific 69 bp variable number tandem repeat (VNTR) in the last intron of WDR7, which exhibits striking variability in both copy number and nucleotide composition, as revealed by long-read sequencing. In addition, greater repeat copy number is significantly enriched in three independent cohorts of individuals with sporadic amyotrophic lateral sclerosis (ALS). Each unit of the repeat forms a stem-loop structure with the potential to produce microRNAs, and the repeat RNA can aggregate when expressed in cells. We leveraged its remarkable sequence variability to align the repeat in 288 samples and uncover its mechanism of expansion. We found that the repeat expands in the 3′-5′ direction, in groups of repeat units divisible by two. The expansion patterns we observed were consistent with duplication events, and a replication error called template switching. We also observed that the VNTR is expanded in both Denisovan and Neanderthal genomes but is fixed at one copy or fewer in non-human primates. Evaluating the repeat in 1000 Genomes Project samples reveals that some repeat segments are solely present or absent in certain geographic populations. The large size of the repeat unit in this VNTR, along with our multiplexed sequencing strategy, provides an unprecedented opportunity to study mechanisms of repeat expansion, and a framework for evaluating the roles of VNTRs in human evolution and disease.

Sensitive detection of two biological events in vivo has long been a goal in bioluminescence imaging. Antares, a fusion of the luciferase NanoLuc to the orange fluorescent protein CyOFP, has emerged as a bright bioluminescent reporter with orthogonal substrate specificity to firefly luciferase (FLuc) and its derivatives such as AkaLuc. However, the brightness of Antares in mice is limited by the poor solubility and bioavailability of the NanoLuc substrate furimazine. Here, we report a new substrate, hydrofurimazine, whose enhanced aqueous solubility allows delivery of higher doses to mice. In the liver, Antares with hydrofurimazine exhibited similar brightness to AkaLuc with its substrate AkaLumine. Further chemical exploration generated a second substrate, fluorofurimazine, with even higher brightness in vivo. We used Antares with fluorofurimazine to track tumor size and AkaLuc with AkaLumine to visualize CAR-T cells within the same mice, demonstrating the ability to perform two-population imaging with these two luciferase systems. NanoLuc substrates with improved solubility and bioavailability, hydrofurimazine and fluorofurimazine, strongly enhance bioluminescence signals in vivo and enable bright dual-color bioluminescent imaging with AkaLuc and AkaLumine.

Homologous recombination (HR)-based gene therapy using adeno-associated viruses (AAV-HR) without nucleases has several advantages over classic gene therapy, especially the potential for permanent transgene expression. However, the low efficiency of AAV-HR remains a major limitation. Here, we tested a series of small-molecule compounds and found that ribonucleotide reductase (RNR) inhibitors substantially enhance AAV-HR efficiency in mouse and human liver cell lines approximately threefold. Short-term administration of the RNR inhibitor fludarabine increased the in vivo efficiency of both non-nuclease- and CRISPR/Cas9-mediated AAV-HR two- to sevenfold in the murine liver, without causing overt toxicity. Fludarabine administration induced transient DNA damage signaling in both proliferating and quiescent hepatocytes. Notably, the majority of AAV-HR events occurred in non-proliferating hepatocytes in both fludarabine-treated and control mice, suggesting that the induction of transient DNA repair signaling in non-dividing hepatocytes was responsible for enhancing AAV-HR efficiency in mice. These results suggest that use of a clinically approved RNR inhibitor can potentiate AAV-HR-based genome-editing therapeutics.

Summary: tRNA-derived small RNAs (tsRNAs) have been implicated in many cellular processes, yet the detailed mechanisms are not well defined. We previously found that the 3′ end of Leu-CAG tRNA-derived small RNA (LeuCAG3′tsRNA) regulates ribosome biogenesis in humans by maintaining ribosomal protein S28 (RPS28) levels. The tsRNA binds to coding (CDS) and non-coding 3′ UTR sequence in the RPS28 mRNA, altering its secondary structure and enhancing its translation. Here we report that the functional 3′ UTR target site is present in primates while the CDS target site is present in many vertebrates. We establish that this tsRNA also regulates mouse Rps28 translation by interacting with the CDS target site. We further establish that the change in mRNA translation occurred at a post-initiation step in both species. Overall, our results suggest that LeuCAG3′tsRNA might maintain ribosome biogenesis through a conserved gene regulatory mechanism in vertebrates. : Kim et al. determined that the LeuCAG3′tsRNA target site in the RPS28 coding sequence (CDS) is conserved in vertebrates and established that the tsRNA regulation of RPS28 mRNA translation is conserved between humans and mice. Their results suggest that the tsRNA-regulated mRNA translation might be a conserved process. Keywords: tRNA-derived small RNAs, tsRNA, tRF, tRNA fragments, ribosomal proteins, translation

Fluorescent indicators are used widely to visualize calcium dynamics downstream of membrane depolarization or G-protein-coupled receptor activation, but are poorly suited for non-invasive imaging in mammals. Here, we report a bright calcium-modulated bioluminescent indicator named Orange CaMBI (Orange Calcium-modulated Bioluminescent Indicator). Orange CaMBI reports calcium dynamics in single cells and, in the context of a transgenic mouse, reveals calcium oscillations in whole organs in an entirely non-invasive manner.

Emerging evidence indicates that tRNA-derived small RNAs (tsRNAs) are involved in fine-tuning gene expression and become dysregulated in various cancers. We recently showed that the 22nt LeuCAG3´tsRNA from the 3´ end of tRNALeu is required for efficient translation of a ribosomal protein mRNA and ribosome biogenesis. Inactivation of this 3´tsRNA induced apoptosis in rapidly dividing cells and suppressed the growth of a patient-derived orthotopic hepatocellular carcinoma in mice. The mechanism involved in the generation of the 3´tsRNAs remains elusive and it is unclear if the 3´-ends of 3´tsRNAs are aminoacylated. Here we report an enzymatic method utilizing exonuclease T to determine the 3´charging status of tRNAs and tsRNAs. Our results showed that the LeuCAG3´tsRNA, and two other 3´tsRNAs are fully aminoacylated. When the leucyl-tRNA synthetase (LARS1) was inhibited, there was no change in the total tRNALeu concentration but a reduction in both the charged tRNALeu and LeuCAG3´tsRNA, suggesting the 3´tsRNAs are fully charged and originated solely from the charged mature tRNA. Altering LARS1 expression or the expression of various tRNALeu mutants were also shown to affect the generation of the LeuCAG3´tsRNA further suggesting they are created in a highly regulated process. The fact that the 3´tsRNAs are aminoacylated and their production is regulated provides additional insights into their importance in post-transcriptional gene regulation that includes coordinating the production of the protein synthetic machinery., Author summary tRNAs were previously considered only as structural RNAs that read the genetic code from mRNAs to add the appropriate amino acids to the growing polypeptide chain. In recent years, it has been discovered that tRNAs can have non-canonical gene regulatory functions through the production of various types of tRNA-generated small RNAs (tsRNAs). We have studied tsRNAs derived from the 3´ end of the mature tRNA (3´tsRNAs). The LeuCAG3´tsRNA promotes the translation of a specific ribosomal protein mRNA by altering mRNA secondary structure, ultimately controlling ribosome biogenesis. This suggests that 3´tsRNAs may represent another means of regulating mRNA translation and protein synthesis. Additionally, the LeuCAG3´tsRNA was shown to be a useful target for treating a humanized hepatocellular carcinoma model in mice. In the current study, we establish a method showing that the 3´tsRNAs are generated from tRNAs that are aminoacylated (attached with an amino acid). Moreover, we found the concentrations of 3´tsRNAs generated in a cell are dictated at least in part by the enzymes that conjugate the specific amino acids with cognate tRNAs. This suggests 3´tsRNA generation is a highly regulated process and further points to the complexity of this additional layer of post-transcriptional gene regulation.

Emerging evidence indicates that tRNA-derived small RNAs (tsRNAs) are involved in fine-tuning gene expression and become dysregulated in various cancers. We recently showed that the 22nt LeuCAG tsRNA from 3’ end of tRNALeu is required for efficient translation of a ribosomal protein mRNA and ribosome biogenesis. Inactivation of this tsRNA induced apoptosis in rapidly dividing cells and suppressed the growth of a patient derived orthotopic hepatocellular carcinoma in mice. The mechanism involved in the generation of the 3’-tsRNAs remains elusive and it is unclear if the 3’-ends of 3’-tsRNAs are aminoacylated. Here we report an enzymatic method utilizing exonuclease T to determine the 3’charging status of tRNAs and tsRNAs. Our results showed that the LeuCAG 3’-tsRNA is fully charged and originated solely from charged mature tRNA. When the leucyl-tRNA synthetase was knocked down, less tsRNA was generated while the mature tRNA was not reduced further supporting that tsRNA generation is regulated. The fact that the 3’-tsRNA is aminoacylated has implications for their biogenesis and provides additional insights into their biological role in post-transcriptional gene regulation.

Recombinant adeno-associated viral (rAAV) vectors continue to gain popularity for in vivo therapeutic gene delivery. Homologous recombination-based gene therapy using rAAV (AAV-HR) without nucleases has several advantages over classical gene therapy, especially when targeting the liver in neonatal/pediatric populations due to its potential for permanent sustained transgene expression. However, the low efficiency of AAV-HR remains a limitation for some clinical applications. Here, we tested series of small molecule compounds with different mechanisms of action in the context of AAV-HR and identified that ribonucleotide reductase (RNR) inhibitors significantly enhanced the AAV-HR efficiency in mouse and human liver cell lines. Furthermore, short term administration of the RNR inhibitor fludarabine increased the in vivo efficiency of both non-nuclease and CRISPR/Cas9-mediated AAV-HR in the murine liver, without causing toxicity. Mechanistic experiments showed that fludarabine administration induced transient DNA damage signaling in both proliferating and quiescent hepatocytes. Surprisingly, in vivo BrdU labeling implicated that the majority of AAV-HR events occurred in non-proliferating hepatocytes in both fludarabine-treated and control mice. These studies suggested that the induction of transient DNA repair signaling in non-dividing hepatocytes was responsible for enhancing the efficiency of AAV-HR in mice during RNR inhibition. In total, we show the use of a clinically approved RNR inhibitor can enhance AAV-HR based genome editing therapeutics.

Recombinant adeno-associated virus (rAAV) vectors have the unique property of being able to perform genomic targeted integration (TI) without inducing a double-strand break (DSB). In order to improve our understanding of the mechanism behind TI mediated by AAV and improve its efficiency, we performed an unbiased genetic screen in human cells using a promoterless AAV-homologous recombination (AAV-HR) vector system. We identified that the inhibition of the Fanconi anemia complementation group M (FANCM) protein enhanced AAV-HR-mediated TI efficiencies in different cultured human cells by ∼6- to 9-fold. The combined knockdown of the FANCM and two proteins also associated with the FANCM complex, RecQ-mediated genome instability 1 (RMI1) and Bloom DNA helicase (BLM) from the BLM-topoisomerase IIIα (TOP3A)-RMI (BTR) dissolvase complex (RMI1, having also been identified in our screen), led to the enhancement of AAV-HR-mediated TI up to ∼17 times. AAV-HR-mediated TI in the presence of a nuclease (CRISPR-Cas9) was also increased by ∼1.5- to 2-fold in FANCM and RMI1 knockout cells, respectively. Furthermore, knockdown of FANCM in human CD34(+) hematopoietic stem and progenitor cells (HSPCs) increased AAV-HR-mediated TI by ∼3.5-fold. This study expands our knowledge on the mechanisms related to AAV-mediated TI, and it highlights new pathways that might be manipulated for future improvements in AAV-HR-mediated TI.

Recombinant adeno-associated virus (rAAV) vectors have the unique ability to promote targeted integration of transgenes via homologous recombination at specified genomic sites, reaching frequencies of 0.1%–1%. We studied genomic parameters that influence targeting efficiencies on a large scale. To do this, we generated more than 1,000 engineered, doxycycline-inducible target sites in the human HAP1 cell line and infected this polyclonal population with a library of AAV-DJ targeting vectors, with each carrying a unique barcode. The heterogeneity of barcode integration at each target site provided an assessment of targeting efficiency at that locus. We compared targeting efficiency with and without target site transcription for identical chromosomal positions. Targeting efficiency was enhanced by target site transcription, while chromatin accessibility was associated with an increased likelihood of targeting. ChromHMM chromatin states characterizing transcription and enhancers in wild-type K562 cells were also associated with increased AAV-HR efficiency with and without target site transcription, respectively. Furthermore, the amenability of a site to targeting was influenced by the endogenous transcriptional level of intersecting genes. These results define important parameters that may not only assist in designing optimal targeting vectors for genome editing, but also provide new insights into the mechanism of AAV-mediated homologous recombination.

Decades after identification as essential for protein synthesis, transfer RNAs (tRNAs) have been implicated in various cellular processes beyond translation. tRNA-derived small RNAs (tsRNAs), referred to as tRNA-derived fragments (tRFs) or tRNA-derived, stress-induced RNAs (tiRNAs), are produced by cleavage at different sites from mature or pre-tRNAs. They are classified into six major types representing potentially thousands of unique sequences and have been implicated to play a wide variety of regulatory roles in maintaining normal homeostasis, cancer cell viability, tumorigenesis, ribosome biogenesis, chromatin remodeling, translational regulation, intergenerational inheritance, retrotransposon regulation, and viral replication. However, the detailed mechanisms governing these processes remain unknown. Aberrant expression of tsRNAs is found in various human disease conditions, suggesting that a further understanding of the regulatory role of tsRNAs will assist in identifying novel biomarkers, potential therapeutic targets, and gene-regulatory tools. Here, we highlight the classification, biogenesis, and biological role of tsRNAs in regulatory mechanisms of normal and disease states.

SUMMARYMaternal drug exposure during pregnancy increases the risks of developmental cardiotoxicity, leading to congenital heart defects (CHDs). In this study, we used human stem cells as anin-vitrosystem to interrogate the mechanisms underlying drug-induced toxicity during cardiomyocyte differentiation, including anticancer tyrosine kinase inhibitor (TKI) drugs (imatinib, sunitinib, and vandetanib). H1-ESCs were treated with these drugs at sublethal levels during cardiomyocyte differentiation. We found that early exposure to TKIs during differentiation induced obvious toxic effects in differentiated cardiomyocytes, including disarranged sarcomere structure, interrupted Ca2+-handling, and impaired mitochondrial function. As sunitinib exposure showed the most significant developmental cardiotoxicity of all TKIs, we further examine its effect with in-vivo experiments. Maternal sunitinib exposure caused fetal death, bioaccumulation, and histopathologic changes in the neonatal mice. Integrative analysis of both transcriptomic and chromatin accessibility landscapes revealed that TKI-exposure altered GATA4-mediated regulatory network, which included key mitochondrial genes. Overexpression of GATA4 with CRISPR-activation restored morphologies, contraction, and mitochondria function in cardiomyocytes upon TKI exposure early during differentiation. Altogether, our study identified a novel crosstalk mechanism between GATA4 activity and mitochondrial function during cardiomyocyte differentiation, and revealed potential therapeutic approaches for reducing TKI-induced developmental cardiotoxicity for human health.HighlightsEarly-stage exposure to TKIs induced cardiotoxicity and mitochondrial dysfunctionGATA4 transcriptional activity is inhibited by TKIsNetwork analysis reveals interactions between GATA4 and mitochondrial genesGATA4-overexpression rescues cardiomyocytes and mitochondria from TKI exposure

Despite early successes using recombinant adeno-associated virus (rAAV) vectors in clinical gene therapy trials, limitations remain making additional advancements a necessity. Some of the challenges include variable levels of pre-existing neutralizing antibodies and poor transduction in specific target tissues and/or diseases. In addition, readministration of an rAAV vector is in general not possible due to the immune response against the capsid. Recombinant adeno-associated virus (AAV) vectors with novel capsids can be isolated in nature or developed through different directed evolution strategies. However, in most cases, the process of AAV selection is not well understood and new strategies are required to define the best parameters to develop more efficient and functional rAAV capsids. Therefore, the use of barcoding for AAV capsid libraries, which can be screened by high-throughput sequencing, provides a powerful tool to track AAV capsid evolution and potentially improve AAV capsid library screens. In this study, we examined how different parameters affect the screen of two different AAV libraries in two human cell types. We uncovered new and unexpected insights in how to maximize the likelihood of obtaining AAV variants with the desired properties. The major findings of the study are the following. (1) Inclusion of helper-virus for AAV replication can selectively propagate variants that can replicate to higher titers, but are not necessarily better at transduction. (2) Competition between AAVs with specific capsids can take place in cells that have been infected with different AAVs. (3) The use of low multiplicity of infections for infection results in more variation between screens and is not optimal at selecting the most desired capsids. (4) Using multiple rounds of selection can be counterproductive. We conclude that each of these parameters should be taken into consideration when screening AAV libraries for enhanced properties of interest.

It is important for brands to appropriately respond when their athlete endorsers are involved in a scandal. The present study examines how consumer evaluations of endorsed brands are influenced by a brand’s response to an endorser scandal. A 2 (brand response strategy type: maintenance vs. termination) × 2 (endorser scandal type: competence-relevant vs. competence-irrelevant) between-subjects experiment is conducted. Specifically, the authors focus on the perceived appropriateness of the response strategy and consumer attitudes toward an endorsed brand. Subjects were recruited from Amazon Mechanical Turk ( N = 111). Consumers perceive that terminating an endorsement contract with a scandalized endorser is more appropriate than maintaining the relationship. This is particularly true when celebrity endorsers are involved in competence-relevant scandals. A further analysis provided support for the idea that perceived “appropriateness” mediates the relationship between competence-relevant scandal and consumer attitude toward an endorsed brand. A termination strategy was considered appropriate when scandalized endorsers engaged in competence-relevant scandals, which eventually lead to more favorable consumer evaluations toward an endorsed brand.

Despite some of the recent examinations of an athlete’s reputational crisis (ARC), their negative spillover effects on endorsed and competing brands have been overlooked. The purpose of this study is to investigate the relationships between perceived severity, athlete endorser credibility (i.e., incompetence, untrustworthiness), and attitudes towards endorsed and competing brands. To enhance theoretical understanding of the phenomenon, the moderating role of consumer knowledge was also tested. Participants were recruited from Amazon Mechanical Turk ( N = 339). A multigroup structural equation model was employed to test the hypothesized model. Results indicated that the severity of an ARC is associated with the perceived incompetence and untrustworthiness of focal athletes. Perceived incompetence is associated with negative evaluation of an endorsed brand. Furthermore, this impact is significantly stronger for consumers with greater knowledge of the athletes than those who are less knowledgeable. Interestingly, competitor brands received negative impact indirectly from the athlete endorsers’ incompetence. This spillover effect is also manifested differently depending on the level of consumer knowledge.

While higher education usually focuses on curriculum development and research to advance sustainability, an alternative approach is to collaborate with business. Collegiate green teams were formed to offer an innovative means to effectively promote business action on sustainability. This paper (a) describes a pilot multidisciplinary student/business internship program, and (b) uses program outcomes and surveys to discern benefits and refine a collaborative approach to taking action on sustainability. Evidence was gathered from participant surveys, administrator's observations, and the managerial assessments of green team reports and presentations to assess the collaborative model. Substantive evidence for effective team building was indicated by high scores among student team participants on measures of team cohesion, viability, satisfaction, and performance. Post-program observations by supervisors further indicated significant team learning and performance on tasks among teams. Collaborative training clearly boosted and broadened engagement among business employees and this spurred action on sustainability. The internship provided students with real-world experience and helped link managers to their local communities.

Transfer-RNA-derived small RNAs (tsRNAs; also called tRNA-derived fragments) are an abundant class of small non-coding RNAs whose biological roles are not well understood. Here we show that inhibition of a specific tsRNA, LeuCAG3′tsRNA, induces apoptosis in rapidly dividing cells in vitro and in a patient-derived orthotopic hepatocellular carcinoma model in mice. This tsRNA binds at least two ribosomal protein mRNAs (RPS28 and RPS15) to enhance their translation. A decrease in translation of RPS28 mRNA blocks pre-18S ribosomal RNA processing, resulting in a reduction in the number of 40S ribosomal subunits. These data establish a post-transcriptional mechanism that can fine-tune gene expression during different physiological states and provide a potential new target for treating cancer. A 22-nucleotide fragment of a transfer RNA regulates translation by binding to the mRNA of a ribosomal protein and increasing its expression, and downregulation of the fragment in patient-derived liver tumour cells reduces tumour growth in mice. The functional roles of small RNA fragments derived from tRNAs are not well known, but evidence is growing that some play a part in various cellular processes. Mark Kay and colleagues show that a 22-nucleotide fragment from the 3′ end of leucine tRNA can regulate translation. The fragment binds to the mRNA of a ribosomal protein to upregulate its expression. When this interaction is suppressed in human cells in culture, cell death occurs. Decreasing the levels of the tRNA fragment with an antisense oligonucleotide can slow the growth of liver tumours in mice. Technologies aimed at reducing expression of this tRNA fragment might have utility in treating cancer.

Hepatocytes represent an important target for gene therapy and editing of single-gene disorders. In α-1 antitrypsin (AAT) deficiency, one missense mutation results in impaired secretion of AAT. In most patients, lung damage occurs due to a lack of AAT-mediated protection of lung elastin from neutrophil elastase. In some patients, accumulation of misfolded PiZ mutant AAT protein triggers hepatocyte injury, leading to inflammation and cirrhosis. We hypothesized that correcting the Z mutant defect in hepatocytes would confer a selective advantage for repopulation of hepatocytes within an intact liver. A human PiZ allele was crossed onto an immune-deficient (NSG) strain to create a recipient strain (NSG-PiZ) for human hepatocyte xenotransplantation. Results indicate that NSG-PiZ recipients support heightened engraftment of normal human primary hepatocytes as compared with NSG recipients. This model can therefore be used to test hepatocyte cell therapies for AATD, but more broadly it serves as a simple, highly reproducible liver xenograft model. Finally, a promoterless adeno-associated virus (AAV) vector, expressing a wild-type AAT and a synthetic miRNA to silence the endogenous allele, was integrated into the albumin locus. This gene-editing approach leads to a selective advantage of edited hepatocytes, by silencing the mutant protein and augmenting normal AAT production, and improvement of the liver pathology., Borel et al. describe two studies based on misfolded human α-1 antitrypsin (A1AT). First, when A1AT is expressed in livers of NSG, mice it allows for reproducible engraftment of human hepatocytes. Second, gene editing of hepatocytes to decrease misfolded protein results in expansion of corrected cells and amelioration of liver disease.

While gene transfer using recombinant adeno-associated viral (rAAV) vectors has shown success in some clinical trials, there remain many tissues that are not well transduced. Because of the recent success in reprogramming islet-derived cells into functional β cells in animal models, we constructed 2 highly complex barcoded replication competent capsid shuffled libraries and selected for high-transducing variants on primary human islets. We describe the generation of a chimeric AAV capsid (AAV-KP1) that facilitates transduction of primary human islet cells and human embryonic stem cell-derived β cells with up to 10-fold higher efficiency compared with previously studied best-in-class AAV vectors. Remarkably, this chimeric capsid also enabled transduction of both mouse and human hepatocytes at very high levels in a humanized chimeric mouse model, thus providing a versatile vector that has the potential to be used in both preclinical testing and human clinical trials for liver-based diseases and diabetes.

Background: Restrictive cardiomyopathy is a rare heart disease associated with mutations in sarcomeric genes and with phenotypic overlap with hypertrophic cardiomyopathy. There is no approved therapy directed at the underlying cause. Here, we explore the potential of an interfering RNA (RNAi) therapeutic for a human sarcomeric mutation in MYL2 causative of restrictive cardiomyopathy in a mouse model. Methods: A short hairpin RNA (M7.8L) was selected from a pool for specificity and efficacy. Two groups of myosin regulatory light chain N47K transgenic mice were injected with M7.8L packaged in adeno-associated virus 9 at 3 days of age and 60 days of age. Mice were subjected to treadmill exercise and echocardiography after treatment to determine maximal oxygen uptake and left ventricular mass. At the end of treatment, heart, lung, liver, and kidney tissue was harvested to determine viral tropism and for transcriptomic and proteomic analysis. Cardiomyocytes were isolated for single-cell studies. Results: A one-time injection of AAV9-M7.8L RNAi in 3-day-old humanized regulatory light chain mutant transgenic mice silenced the mutated allele (RLC-47K) with minimal effects on the normal allele (RLC-47N) assayed at 16 weeks postinjection. AAV9-M7.8L RNAi suppressed the expression of hypertrophic biomarkers, reduced heart weight, and attenuated a pathological increase in left ventricular mass. Single adult cardiac myocytes from mice treated with AAV9-M7.8L showed partial restoration of contraction, relaxation, and calcium kinetics. In addition, cardiac stress protein biomarkers, such as calmodulin-dependent protein kinase II and the transcription activator Brg1 were reduced, suggesting recovery toward a healthy myocardium. Transcriptome analyses further revealed no significant changes of argonaute ( AGO1 , AGO2 ) and endoribonuclease dicer ( DICER1 ) transcripts, and endogenous microRNAs were preserved, suggesting that the RNAi pathway was not saturated. Conclusions: Our results show the feasibility, efficacy, and safety of RNAi therapeutics directed towards human restrictive cardiomyopathy. This is a promising step toward targeted therapy for a prevalent human disease.

While gene transfer using recombinant adeno-associated viral (rAAV) vectors have shown success in some clinical trials, there remain many tissues that are not well transduced. Because of the recent success in reprogramming islet derived cells into functional β-cells in animal models, we constructed two highly complex barcoded replication competent capsid shuffled libraries and selected for high transducing variants on primary human islets. We describe a chimeric capsid (AAV-KP1) that penetrated and transduced primary human islet cells and human embryonic stem cell derived β-cells with up to 10-fold higher efficiency compared to previously studied best in class AAV vectors. Remarkably, this chimeric capsid was also able to transduce both mouse and human hepatocytes at very high levels in a humanized-chimeric mouse model, thus providing a versatile vector which has the potential to be used in both preclinical testing and human clinical trials for both liver-based diseases and diabetes.

We previously developed a mini-intronic plasmid (MIP) expression system in which the essential bacterial elements for plasmid replication and selection are placed within an engineered intron contained within a universal 5′ UTR noncoding exon. Like minicircle DNA plasmids (devoid of bacterial backbone sequences), MIP plasmids overcome transcriptional silencing of the transgene. However, in addition MIP plasmids increase transgene expression by 2 and often >10 times higher than minicircle vectors in vivo and in vitro. Based on these findings, we examined the effects of the MIP intronic sequences in a recombinant adeno-associated virus (AAV) vector system. Recombinant AAV vectors containing an intron with a bacterial replication origin and bacterial selectable marker increased transgene expression by 40 to 100 times in vivo when compared with conventional AAV vectors. Therefore, inclusion of this noncoding exon/intron sequence upstream of the coding region can substantially enhance AAV-mediated gene expression in vivo.

This article provides a framework to guide the construction of transformative stories by social impact organizations (SIOs) including nonprofit organizations, public policy entities, and for-profit social benefit enterprises. This framework is built from the integration of the academic literature on narratives and narrative construction relevant to SIO story construction. This transformative story construction framework outlines how SIOs can assemble and craft authentic and effective stories that convey the organization's impact, engage audiences, and call those audiences to action as well as how SIOs can develop and manage a portfolio of such stories. The framework also provides recommendations to guide the marketplace practice of transformative story construction by SIOs. Finally, the authors pose questions to engage SIOs in collaborative research to refine the practice of constructing stories with the power to transform.

Orange-red fluorescent proteins (FPs) are widely used in biomedical research for multiplexed epifluorescence microscopy with GFP-based probes, but their different excitation requirements make multiplexing with new advanced microscopy methods difficult. Separately, orange-red FPs are useful for deep-tissue imaging in mammals owing to the relative tissue transmissibility of orange-red light, but their dependence on illumination limits their sensitivity as reporters in deep tissues. Here we describe CyOFP1, a bright, engineered, orange-red FP that is excitable by cyan light. We show that CyOFP1 enables single-excitation multiplexed imaging with GFP-based probes in single-photon and two-photon microscopy, including time-lapse imaging in light-sheet systems. CyOFP1 also serves as an efficient acceptor for resonance energy transfer from the highly catalytic blue-emitting luciferase NanoLuc. An optimized fusion of CyOFP1 and NanoLuc, called Antares, functions as a highly sensitive bioluminescent reporter in vivo, producing substantially brighter signals from deep tissues than firefly luciferase and other bioluminescent proteins.