Loss of DNA repair mechanisms in cardiac myocytes induce dilated cardiomyopathy

Cardiomyopathy is a progressive disease of the myocardium leading to impaired contractility. Genotoxic cancer therapies are known to be potent drivers of cardiomyopathy, whereas causes of spontaneous disease remain unclear. To test the hypothesis that endogenous genotoxic stress contributes to cardiomyopathy, we deleted the DNA repair gene Ercc1 specifically in striated muscle using a floxed allele of Ercc1 and mice expressing Cre under control of the muscle-specific creatinine kinase (Ckmm) promoter or depleted systemically (Ercc1-/D mice). Ckmm-Cre+/- ;Ercc1-/fl mice expired suddenly of heart disease by 7 months of age. As young adults, the hearts of Ckmm-Cre+/- ;Ercc1-/fl mice were structurally and functionally normal, but by 6-months-of-age, there was significant ventricular dilation, wall thinning, interstitial fibrosis, and systolic dysfunction indicative of dilated cardiomyopathy. Cardiac tissue from the tissue-specific or systemic model showed increased apoptosis and cardiac myocytes from Ckmm-Cre+/- ;Ercc1-/fl mice were hypersensitive to genotoxins, resulting in apoptosis. p53 levels and target gene expression, including several antioxidants, were increased in cardiac tissue from Ckmm-Cre+/- ;Ercc1-/fl and Ercc1-/D mice. Despite this, cardiac tissue from older mutant mice showed evidence of increased oxidative stress. Genetic or pharmacologic inhibition of p53 attenuated apoptosis and improved disease markers. Similarly, overexpression of mitochondrial-targeted catalase improved disease markers. Together, these data support the conclusion that DNA damage produced endogenously can drive cardiac disease and does so mechanistically via chronic activation of p53 and increased oxidative stress, driving cardiac myocyte apoptosis, dilated cardiomyopathy, and sudden death.

An aged immune system drives senescence and ageing of solid organs

Ageing of the immune system, or immunosenescence, contributes to the morbidity and mortality of the elderly1,2. To define the contribution of immune system ageing to organism ageing, here we selectively deleted Ercc1, which encodes a crucial DNA repair protein3,4, in mouse haematopoietic cells to increase the burden of endogenous DNA damage and thereby senescence5-7 in the immune system only. We show that Vav-iCre+/-;Ercc1-/fl mice were healthy into adulthood, then displayed premature onset of immunosenescence characterized by attrition and senescence of specific immune cell populations and impaired immune function, similar to changes that occur during ageing in wild-type mice8-10. Notably, non-lymphoid organs also showed increased senescence and damage, which suggests that senescent, aged immune cells can promote systemic ageing. The transplantation of splenocytes from Vav-iCre+/-;Ercc1-/fl or aged wild-type mice into young mice induced senescence in trans, whereas the transplantation of young immune cells attenuated senescence. The treatment of Vav-iCre+/-;Ercc1-/fl mice with rapamycin reduced markers of senescence in immune cells and improved immune function11,12. These data demonstrate that an aged, senescent immune system has a causal role in driving systemic ageing and therefore represents a key therapeutic target to extend healthy ageing.

Immunogenic Chemotherapy Enhances Recruitment of CAR-T Cells to Lung Tumors and Improves Antitumor Efficacy when Combined with Checkpoint Blockade

Adoptive therapy using chimeric antigen receptor-modified T cells (CAR-T cells) is effective in hematologic but not epithelial malignancies, which cause the greatest mortality. In breast and lung cancer patients, CAR-T cells targeting the tumor-associated antigen receptor tyrosine kinase-like orphan receptor 1 (ROR1) infiltrate tumors poorly and become dysfunctional. To test strategies for enhancing efficacy, we adapted the Kras^LSL-G12D/+;p53^f/f autochthonous model of lung adenocarcinoma to express the CAR target ROR1. Murine ROR1 CAR-T cells transferred after lymphodepletion with cyclophosphamide (Cy) transiently control tumor growth but infiltrate tumors poorly and lose function, similar to what is seen in patients. Adding oxaliplatin (Ox) to the lymphodepletion regimen activates tumor macrophages to express T-cell-recruiting chemokines, resulting in improved CAR-T cell infiltration, remodeling of the tumor microenvironment, and increased tumor sensitivity to anti-PD-L1. Combination therapy with Ox/Cy and anti-PD-L1 synergistically improves CAR-T cell-mediated tumor control and survival, providing a strategy to improve CAR-T cell efficacy in the clinic.

The androgen receptor regulates a druggable translational regulon in advanced prostate cancer

The androgen receptor (AR) is a driver of cellular differentiation and prostate cancer development. An extensive body of work has linked these normal and aberrant cellular processes to mRNA transcription; however, the extent to which AR regulates posttranscriptional gene regulation remains unknown. Here, we demonstrate that AR uses the translation machinery to shape the cellular proteome. We show that AR is a negative regulator of protein synthesis and identify an unexpected relationship between AR and the process of translation initiation in vivo. This is mediated through direct transcriptional control of the translation inhibitor 4EBP1. We demonstrate that lowering AR abundance increases the assembly of the eIF4F translation initiation complex, which drives enhanced tumor cell proliferation. Furthermore, we uncover a network of pro-proliferation mRNAs characterized by a guanine-rich cis-regulatory element that is particularly sensitive to eIF4F hyperactivity. Using both genetic and pharmacologic methods, we demonstrate that dissociation of the eIF4F complex reverses the proliferation program, resulting in decreased tumor growth and improved survival in preclinical models. Our findings reveal a druggable nexus that functionally links the processes of mRNA transcription and translation initiation in an emerging class of lethal AR-deficient prostate cancer.

Validation of a geropathology grading system for aging mouse studies

An understanding of early-onset mechanisms underlying age-related changes can be obtained by evaluating changes that precede frailty and end of life using histological characterization of age-related lesions. Histopathology-based information as a component of aging studies in mice can complement and add context to molecular, cellular, and physiologic data, but there is a lack of information regarding scoring criteria and lesion grading guidelines. This report describes the validation of a grading system, designated as the geropathology grading platform (GGP), which generated a composite lesion score (CLS) for comparison of histological lesion scores in tissues from aging mice. To assess reproducibility of the scoring system, multiple veterinary pathologists independently scored the same slides from the heart, lung, liver, and kidney from two different strains (C57BL/6 and CB6F1) of male mice at 8, 16, 24, and 32 months of age. There was moderate to high agreement between pathologists, particularly when agreement within a 1-point range was considered. CLS for all organs was significantly higher in older versus younger mice, suggesting that the GGP was reliable for detecting age-related pathology in mice. The overall results suggest that the GGP guidelines reliably distinguish between younger and older mice and may therefore be accurate in distinguishing between experimental groups of mice with more, or less, age-related pathology.

Crebbp Loss Drives Small Cell Lung Cancer and Increases Sensitivity to HDAC Inhibition

CREBBP, encoding an acetyltransferase, is among the most frequently mutated genes in small cell lung cancer (SCLC), a deadly neuroendocrine tumor type. We report acceleration of SCLC upon Crebbp inactivation in an autochthonous mouse model. Extending these observations beyond the lung, broad Crebbp deletion in mouse neuroendocrine cells cooperated with Rb1/Trp53 loss to promote neuroendocrine thyroid and pituitary carcinomas. Gene expression analyses showed that Crebbp loss results in reduced expression of tight junction and cell adhesion genes, including Cdh1, across neuroendocrine tumor types, whereas suppression of Cdh1 promoted transformation in SCLC. CDH1 and other adhesion genes exhibited reduced histone acetylation with Crebbp inactivation. Treatment with the histone deacetylase (HDAC) inhibitor Pracinostat increased histone acetylation and restored CDH1 expression. In addition, a subset of Rb1/Trp53/Crebbp-deficient SCLC exhibited exceptional responses to Pracinostat in vivo Thus, CREBBP acts as a potent tumor suppressor in SCLC, and inactivation of CREBBP enhances responses to a targeted therapy.Significance: Our findings demonstrate that CREBBP loss in SCLC reduces histone acetylation and transcription of cellular adhesion genes, while driving tumorigenesis. These effects can be partially restored by HDAC inhibition, which exhibited enhanced effectiveness in Crebbp-deleted tumors. These data provide a rationale for selectively treating CREBBP-mutant SCLC with HDAC inhibitors. Cancer Discov; 8(11); 1422-37. ©2018 AACR. This article is highlighted in the In This Issue feature, p. 1333.

Anti-Inducible Costimulator Monoclonal Antibody Treatment of Canine Chronic Graft-versus-Host Disease

In murine model systems inducible costimulator (ICOS) signaling has been implicated in the formation of chronic graft-versus-host disease (GVHD). Previously, we showed that chronic GVHD can be reproducibly produced in the dog hematopoietic cell transplantation (HCT) model and that ICOS expression is upregulated on T cells in dogs with chronic GVHD. The goal of the present study was to determine whether administration of a short course of anti-canine ICOS mAb could alter the rapid and progressive course of chronic GVHD. Five dogs underwent HCT from dog leukocyte antigen mismatched unrelated donors after total body irradiation. Postgrafting immunosuppression consisted of methotrexate (days 1, 3, 6, and 11) and cyclosporine (days -1 through 78). Anti-ICOS mAb (3 injections, 72 hours apart) was administered upon diagnosis of GVHD. One dog failed to respond to anti-ICOS mAb therapy and succumbed to chronic GVHD in a time course similar to control untreated dogs. Overall, anti-ICOS-treated dogs experienced a significant prolongation in survival from the time of diagnosis of chronic GVHD compared with control dogs. Within the limitations of the number of study dogs we suggest that a short course of anti-ICOS mAb may be useful in the treatment of chronic canine GVHD.

A New Preclinical Paradigm for Testing Anti-Aging Therapeutics

Testing drugs for anti-aging effects has historically been conducted in mouse life-span studies, but are costly and time consuming, and more importantly, difficult to recapitulate in humans. In addition, life-span studies in mice are not well suited to testing drug combinations that target multiple factors involved in aging. Additional paradigms for testing therapeutics aimed at slowing aging are needed. A new paradigm, designated as the Geropathology Grading Platform (GGP), is based on a standardized set of guidelines developed to detect the presence or absence of low-impact histopathological lesions and to determine the level of severity of high-impact lesions in organs from aged mice. The GGP generates a numerical score for each age-related lesion in an organ, summed for total lesions, and averaged over multiple mice to obtain a composite lesion score (CLS). Preliminary studies show that the platform generates CLSs that increase with the age of mice in an organ-dependent manner. The CLSs are sensitive enough to detect changes elicited by interventions that extend mouse life span, and thus help validate the GGP as a novel tool to measure biological aging. While currently optimized for mice, the GGP could be adapted to any preclinical animal model.

In situ programming of leukaemia-specific T cells using synthetic DNA nanocarriers

An emerging approach for treating cancer involves programming patient-derived T cells with genes encoding disease-specific chimeric antigen receptors (CARs), so that they can combat tumour cells once they are reinfused. Although trials of this therapy have produced impressive results, the in vitro methods they require to generate large numbers of tumour-specific T cells are too elaborate for widespread application to treat cancer patients. Here, we describe a method to quickly program circulating T cells with tumour-recognizing capabilities, thus avoiding these complications. Specifically, we demonstrate that DNA-carrying nanoparticles can efficiently introduce leukaemia-targeting CAR genes into T-cell nuclei, thereby bringing about long-term disease remission. These polymer nanoparticles are easy to manufacture in a stable form, which simplifies storage and reduces cost. Our technology may therefore provide a practical, broadly applicable treatment that can generate anti-tumour immunity 'on demand' for oncologists in a variety of settings.

Biopolymers codelivering engineered T cells and STING agonists can eliminate heterogeneous tumors

Therapies using T cells that are programmed to express chimeric antigen receptors (CAR T cells) consistently produce positive results in patients with hematologic malignancies. However, CAR T cell treatments are less effective in solid tumors for several reasons. First, lymphocytes do not efficiently target CAR T cells; second, solid tumors create an immunosuppressive microenvironment that inactivates T cell responses; and third, solid cancers are typified by phenotypic diversity and thus include cells that do not express proteins targeted by the engineered receptors, enabling the formation of escape variants that elude CAR T cell targeting. Here, we have tested implantable biopolymer devices that deliver CAR T cells directly to the surfaces of solid tumors, thereby exposing them to high concentrations of immune cells for a substantial time period. In immunocompetent orthotopic mouse models of pancreatic cancer and melanoma, we found that CAR T cells can migrate from biopolymer scaffolds and eradicate tumors more effectively than does systemic delivery of the same cells. We have also demonstrated that codelivery of stimulator of IFN genes (STING) agonists stimulates immune responses to eliminate tumor cells that are not recognized by the adoptively transferred lymphocytes. Thus, these devices may improve the effectiveness of CAR T cell therapy in solid tumors and help protect against the emergence of escape variants.

Detection of influenza viral gene in European starlings and experimental infection

BACKGROUND

European starlings (Sturnus vulgaris) are common, widely distributed birds in North America that frequently come into contact with agricultural operations. However, starlings have been one of the neglected land-based wild bird species for influenza surveillance.

OBJECTIVES

To study the potential role of starlings in the ecology and epidemiology of influenza virus.

METHODS

We collected 328 digestive and 156 tracheal samples from starlings in Ohio in years 2007 (July) to 2008 (August) and screened for the presence of influenza virus by real-time RT-PCR, standard RT-PCR and virus isolation using embryonated chicken eggs. In addition, we conducted an experimental infection study to evaluate the replication and induction of antibody response by two low pathogenic avian influenza (AI) viruses in starlings.

RESULTS

Although virus isolation was negative, we confirmed 21 influenza positive digestive and tracheal samples by real-time and standard RT-PCR tests. Phylogenetic analysis revealed that five NS genes recovered from Starlings belonged to NS subtype A and were most similar to the NS genes from a wild aquatic bird origin isolate from Ohio. Experimental infection studies using two low pathogenic AI strains showed that starlings could be infected, shed virus, and seroconvert.

CONCLUSIONS

This study shows that starlings can carry influenza virus that is genetically similar to wild aquatic bird origin strains and may serve as a carrier of influenza virus to domestic animals.

Detection of influenza A viruses in eggs laid by infected turkeys

Studies are limited on evaluating the potential of influenza viruses for egg-borne dissemination. In our previous studies, experimental infection of breeder turkeys with A/turkey/Ohio/313053/04 resulted in drastic declines in egg production, and we confirmed high levels of virus replication and an abundant distribution of avian-specific alpha2,3 sialic acid-gal receptors in the oviduct of these turkeys. In the present study, following experimental inoculation of A/turkey/Ohio/313053/04 in breeder turkeys, we detected these viruses in the albumin of eggs using real-time RT-PCR (RRT-PCR) and virus isolation in embryonated chicken eggs. Swabs from egg shells were also found positive by RRT-PCR. This is the first report of the detection of low pathogenic influenza viruses from internal egg contents following experimental infection. The possibility of hatchery contamination by egg-borne influenza viruses, and the spread of virus during movement of contaminated cracked eggs and egg flats, pose concerns regarding viral dissemination of influenza.

The high susceptibility of turkeys to influenza viruses of different origins implies their importance as potential intermediate hosts

Several previous reports and our studies show that waterfowl-origin influenza viruses can be more easily transmitted to domestic turkeys than chickens. Similarly, studies indicate turkeys to be better hosts for low pathogenic avian influenza viruses isolated from commercial poultry operations and live bird markets in comparison to chickens. Low 50% infectious-dose titers of wild bird as well as poultry-adapted viruses for turkeys further suggest that turkeys can be easily infected following a low-dose exposure. Also, interspecies transmission of swine influenza viruses to turkeys occurs frequently. These findings suggest the role of turkeys as suitable intermediate hosts that can be easily infected with influenza viruses of different origins and that turkeys can act as source of infection for other land-based poultry or even mammals.

Pathobiological characterization of low-pathogenicity H5 avian influenza viruses of diverse origins in chickens, ducks and turkeys

We undertook one of the most comprehensive studies on the replication and intraspecies transmission characteristics of low-pathogenicity avian influenza viruses in ducks, chickens and turkeys. Our results indicated that most of these isolates could replicate and be transmitted in poultry without inducing clinical disease. However, differences in transmission to contact control birds were noted, emphasizing the importance of having contact control cage mates in biological characterization experiments. Ducks supported the replication of viruses of wild aquatic bird origin in their respiratory and digestive tracts equally well. The viruses from wild aquatic birds were not effectively transmitted among chickens. In contrast, the wild-bird isolates and viruses of domestic bird origin from live-bird markets and commercial poultry operations replicated and were transmitted more efficiently in turkeys than in chickens or ducks. We also found a lower minimal infectious dose requirement for infection of turkeys compared to chickens and ducks. Our data support an important role of turkeys as being more susceptible hosts for avian influenza viruses than domestic ducks and chickens. These results highlight the role of turkeys as intermediate or bridging hosts in the transmission of influenza viruses from wild birds to land-based domestic poultry or among different land-based bird species.

Species and age related differences in the type and distribution of influenza virus receptors in different tissues of chickens, ducks and turkeys

We undertook one of the most detailed studies on the distribution of α2,3 sialic acid (SA)-galactose (gal) (avian type) and α2,6SA-gal (human type) receptors on different tissues of chickens, ducks and turkeys of varying age groups. On the tracheal epithelium, all 3 bird species expressed strong positive staining (80-90%) for α2,3SA-gal receptors in the 3 different age groups. In addition, a lesser amount of α2,6SA-gal receptors (30-90%) were observed with slight differences in distribution with age and species. The epithelium of the small and large intestine of turkeys and ducks showed negligible staining for α2,6SA-gal receptors whereas the large intestine consistently showed 40-70% positive staining for α2,3SA-gal receptors. In contrast, a greater amount of staining for α2,3SA-gal (50-80%) and α2,6SA-gal (20-50%) receptors were observed along the epithelium of small and large intestine of chickens. Kidney and esophagus sections from the 3 bird species also expressed both avian and human type receptors. In other tissues examined, brain, breast muscles, bursa, spleen, cecal tonsils and oviduct, human type receptors were absent. Though different viral and receptor components may play roles in successful viral replication and transmission, understanding the receptor types and distribution in different tissues of domestic birds might be good initial tool to understand host factors that promote successful influenza viral infection.

Pathobiology of triple reassortant H3N2 influenza viruses in breeder turkeys and its potential implication for vaccine studies in turkeys

Triple reassortant (TR) H3N2 influenza viruses have been isolated from turkeys in the United States since 2003. These TR H3N2 virus infections have been associated with drastic declines in egg production in breeder turkeys although co-infection with multiple agents could have been responsible for exacerbating the clinical signs. In this study, we experimentally confirmed that TR H3N2 influenza virus alone can cause drastic reduction/complete cessation of egg production and pathology of the reproductive tract in 26-week-old breeder turkeys. We confirmed high levels of virus replication and abundant distribution of avian specific alpha2,3 sialic acid-galactose receptors in the oviduct of these turkeys. Although 2-6-week-old turkeys are routinely used for pathogenicity and vaccine protection studies, the low levels of viral shedding and asymptomatic infections in this age group often pose difficulty in interpretation of results. Our study shows that breeder turkeys should be used to assess the potential pathogenicity of TR H3N2 viruses and the viral titers and pathology of the oviduct as well as egg production data can be good measures of protection following in vivo challenge in vaccine efficacy studies.

Pathogenicity and transmission studies of H5N2 parrot avian influenza virus of Mexican lineage in different poultry species

In 2004, a low pathogenic H5N2 influenza virus (A/parrot/CA/6032/04) was identified in a psittacine bird for the first time in the United States. Sequence and phylogenetic analysis of the hemagglutinin gene grouped the parrot isolate under the Mexican lineage H5N2 viruses (subgroup B) with highest similarity to recent chicken-origin isolates from Guatemala. Antigenic analysis further confirmed the close relatedness of the parrot isolate to Mexican lineage viruses, the highest cross-reactivity being demonstrated to Guatemala isolates. In vivo studies of the parrot isolate in chickens, ducks and turkeys showed that the virus, though did not cause any clinical signs, could replicate to high titers in these birds and efficiently transmit to contact control cage mates. The possibility that the parrot harboring the virus was introduced into the United States as a result of illegal trade across the border provides additional concern for the movement of foreign animal diseases from neighboring countries. Considering the potential threat of the virus to domestic poultry, efforts should be continued to prevent the entry and spread of influenza viruses by imposing effective surveillance and monitoring measures.