miR-181a/b downregulation: a mutation-independent therapeutic approach for inherited retinal diseases.

Inherited retinal diseases (IRDs) are a group of diseases whose common landmark is progressive photoreceptor loss. The development of gene-specific therapies for IRDs is hampered by their wide genetic heterogeneity. Mitochondrial dysfunction is proving to constitute one of the key pathogenic events in IRDs; hence, approaches that enhance mitochondrial activities have a promising therapeutic potential for these conditions. We previously reported that miR-181a/b downregulation boosts mitochondrial turnover in models of primary retinal mitochondrial diseases. Here, we show that miR-181a/b silencing has a beneficial effect also in IRDs. In particular, the injection in the subretinal space of an adeno-associated viral vector (AAV) that harbors a miR-181a/b inhibitor (sponge) sequence (AAV2/8-GFP-Sponge-miR-181a/b) improves retinal morphology and visual function both in models of autosomal dominant (RHO-P347S) and of autosomal recessive (rd10) retinitis pigmentosa. Moreover, we demonstrate that miR-181a/b downregulation modulates the level of the mitochondrial fission-related protein Drp1 and rescues the mitochondrial fragmentation in RHO-P347S photoreceptors. Overall, these data support the potential use of miR-181a/b downregulation as an innovative mutation-independent therapeutic strategy for IRDs, which can be effective both to delay disease progression and to aid gene-specific therapeutic approaches.

miR-181a/b downregulation exerts a protective action on mitochondrial disease models.

Mitochondrial diseases (MDs) are a heterogeneous group of devastating and often fatal disorders due to defective oxidative phosphorylation. Despite the recent advances in mitochondrial medicine, effective therapies are still not available for these conditions. Here, we demonstrate that the microRNAs miR-181a and miR-181b (miR-181a/b) regulate key genes involved in mitochondrial biogenesis and function and that downregulation of these miRNAs enhances mitochondrial turnover in the retina through the coordinated activation of mitochondrial biogenesis and mitophagy. We thus tested the effect of miR-181a/b inactivation in different animal models of MDs, such as microphthalmia with linear skin lesions and Leber's hereditary optic neuropathy. We found that miR-181a/b downregulation strongly protects retinal neurons from cell death and significantly ameliorates the disease phenotype in all tested models. Altogether, our results demonstrate that miR-181a/b regulate mitochondrial homeostasis and that these miRNAs may be effective gene-independent therapeutic targets for MDs characterized by neuronal degeneration.

MiR-211 is essential for adult cone photoreceptor maintenance and visual function.

MicroRNAs (miRNAs) are key post-transcriptional regulators of gene expression that play an important role in the control of fundamental biological processes in both physiological and pathological conditions. Their function in retinal cells is just beginning to be elucidated, and a few have been found to play a role in photoreceptor maintenance and function. MiR-211 is one of the most abundant miRNAs in the developing and adult eye. However, its role in controlling vertebrate visual system development, maintenance and function so far remain incompletely unexplored. Here, by targeted inactivation in a mouse model, we identify a critical role of miR-211 in cone photoreceptor function and survival. MiR-211 knockout (-/-) mice exhibited a progressive cone dystrophy accompanied by significant alterations in visual function. Transcriptome analysis of the retina from miR-211-/- mice during cone degeneration revealed significant alteration of pathways related to cell metabolism. Collectively, this study highlights for the first time the impact of miR-211 function in the retina and significantly contributes to unravelling the role of specific miRNAs in cone photoreceptor function and survival.

Evaluation of the Automated QIAsymphony SP/AS Workflow for Cytomegalovirus DNA Extraction and Amplification from Dried Blood Spots.

OBJECTIVE: Human cytomegalovirus (CMV) can be considered the most important agent of congenital infection. Long-term sequelae of congenital infection occur in about 15% of infants asymptomatic at birth. To avoid long-term sequelae or to reduce their burden, it is necessary to identify infected children for early interventions. CMV DNA can be detected in dried blood spots (DBSs). DBSs have been used in several studies for the retrospective diagnosis of congenital CMV (CCMV). It has been proposed to use DBSs for the newborn screening of CMV infection; however, manual methods are not suitable for newborn screening of CCMV. METHODS: We evaluated in an off-label application the use of an automated instrument, the QIAsymphony SP/AS, in combination with the artus CMV QS-RGQ kit and the RotorGene Q real-time polymerase chain reaction system. RESULTS: We analyzed 100 DBSs from newborns positive or negative for plasma CMV DNA with a 94% concordance in positive samples. CONCLUSIONS: We show that the QIAsymphony SP/AS and RotorGene Q workflow is suitable for CMV DNA extraction and detection from DBSs and that the system correctly identified newborns at risk of late sequelae due to CMV infection.

TGF-ß Controls miR-181/ERK Regulatory Network during Retinal Axon Specification and Growth.

Retinal axon specification and growth are critically sensitive to the dosage of numerous signaling molecules and transcription factors. Subtle variations in the expression levels of key molecules may result in a variety of axonal growth anomalies. miR-181a and miR-181b are two eye-enriched microRNAs whose inactivation in medaka fish leads to alterations of the proper establishment of connectivity and function in the visual system. miR-181a/b are fundamental regulators of MAPK signaling and their role in retinal axon growth and specification is just beginning to be elucidated. Here we demonstrate that miR-181a/b are key nodes in the interplay between TGF-ß and MAPK/ERK within the functional pathways that control retinal axon specification and growth. Using a variety of in vivo and in vitro approaches in medaka fish, we demonstrate that TGF-ß signaling controls the miR-181/ERK regulatory network, which in turn strengthens the TGF-ß-mediated regulation of RhoA degradation. Significantly, these data uncover the role of TGF-ß signaling in vivo, for the first time, in defining the correct wiring and assembly of functional retina neural circuits and further highlight miR-181a/b as key factors in axon specification and growth.

MiR-204 is responsible for inherited retinal dystrophy associated with ocular coloboma.

Ocular developmental disorders, including the group classified as microphthalmia, anophthalmia, and coloboma (MAC) and inherited retinal dystrophies, collectively represent leading causes of hereditary blindness. Characterized by extreme genetic and clinical heterogeneity, the separate groups share many common genetic causes, in particular relating to pathways controlling retinal and retinal pigment epithelial maintenance. To understand these shared pathways and delineate the overlap between these groups, we investigated the genetic cause of an autosomal dominantly inherited condition of retinal dystrophy and bilateral coloboma, present in varying degrees in a large, five-generation family. By linkage analysis and exome sequencing, we identified a previously undescribed heterozygous mutation, n.37 C > T, in the seed region of microRNA-204 (miR-204), which segregates with the disease in all affected individuals. We demonstrated that this mutation determines significant alterations of miR-204 targeting capabilities via in vitro assays, including transcriptome analysis. In vivo injection, in medaka fish (Oryzias latipes), of the mutated miR-204 caused a phenotype consistent with that observed in the family, including photoreceptor alterations with reduced numbers of both cones and rods as a result of increased apoptosis, thereby confirming the pathogenic effect of the n.37 C > T mutation. Finally, knockdown assays in medaka fish demonstrated that miR-204 is necessary for normal photoreceptor function. Overall, these data highlight the importance of miR-204 in the regulation of ocular development and maintenance and provide the first evidence, to our knowledge, of its contribution to eye disease, likely through a gain-of-function mechanism.

miR-181a/b control the assembly of visual circuitry by regulating retinal axon specification and growth.

Connectivity and function of neuronal circuitry require the correct specification and growth of axons and dendrites. Here, we identify the microRNAs miR-181a and miR-181b as key regulators of retinal axon specification and growth. Loss of miR-181a/b in medaka fish (Oryzias latipes) failed to consolidate amacrine cell processes into axons and delayed the growth of retinal ganglion cell (RGC) axons. These alterations were accompanied by defects in visual connectivity and function. We demonstrated that miR-181a/b exert these actions through negative modulation of MAPK/ERK signaling that in turn leads to RhoA reduction and proper neuritogenesis in both amacrine cells and RGCs via local cytoskeletal rearrangement. Our results identify a new pathway for axon specification and growth unraveling a crucial role of miR-181a/b in the proper establishment of visual system connectivity and function.

Evaluation of the siemens HIV antigen-antibody immunoassay.

Fourth-generation assays for the simultaneous detection of human immunodeficiency virus (HIV) antigen and antibodies are available on the international market and are currently used for blood donor screening and for HIV diagnosis. In this study we evaluated the performance of the novel automated fourth-generation ADVIA Centaur® HIV Ag/Ab Combo assay. The assay detected seroconversion at the same bleed or at least one bleed earlier in panels with respect to other assays and showed a detection efficacy equal to those of other assays in a low-titer panel. Samples obtained from blood donors (n = 2,778) or from HIV-positive patients (HIV-1 B subtype, n = 82; non-B subtype, n = 71) were also tested, showing a good correlation with other fourth-generation assays. We assessed the performance of 3 fourth-generation assays for detecting in utero transmitted anti-HIV antibodies and found a more specific detection efficiency with the ADVIA Centaur HIV Ag/Ab Combo assay compared to the other fourth-generation assays.

The ADAMTS18 gene is responsible for autosomal recessive early onset severe retinal dystrophy.

BACKGROUND: Inherited retinal dystrophies, including Retinitis Pigmentosa and Leber Congenital Amaurosis among others, are a group of genetically heterogeneous disorders that lead to variable degrees of visual deficits. They can be caused by mutations in over 100 genes and there is evidence for the presence of as yet unidentified genes in a significant proportion of patients. We aimed at identifying a novel gene for an autosomal recessive form of early onset severe retinal dystrophy in a patient carrying no previously described mutations in known genes. METHODS: An integrated strategy including homozygosity mapping and whole exome sequencing was used to identify the responsible mutation. Functional tests were performed in the medaka fish (Oryzias latipes) model organism to gain further insight into the pathogenic role of the ADAMTS18 gene in eye and central nervous system (CNS) dysfunction. RESULTS: This study identified, in the analyzed patient, a homozygous missense mutation in the ADAMTS18 gene, which was recently linked to Knobloch syndrome, a rare developmental disorder that affects the eye and the occipital skull. In vivo gene knockdown performed in medaka fish confirmed both that the mutation has a pathogenic role and that the inactivation of this gene has a deleterious effect on photoreceptor cell function. CONCLUSION: This study reveals that mutations in the ADAMTS18 gene can cause a broad phenotypic spectrum of eye disorders and contribute to shed further light on the complexity of retinal diseases.

Inhibition of autophagy enhances the effects of E1A-defective oncolytic adenovirus dl922-947 against glioma cells in vitro and in vivo.

Oncolytic viruses represent a novel therapeutic approach for aggressive tumors, such as glioblastoma multiforme, which are resistant to available treatments. Autophagy has been observed in cells infected with oncolytic viruses; however, its role in cell death/survival is unclear. To elucidate the potential therapeutic use of autophagy modulators in association with viral therapy, we analyzed autophagy induction in human glioma cell lines U373MG and U87MG infected with the oncolytic adenovirus dl922-947. dl922-947 infection triggered an autophagic cellular response, as shown by the development of acidic vesicular organelles, LC3-I→LC3-II conversion, and reduction of p62 levels. However, on infection, the Akt/mTOR/p70s6k pathway, which negatively regulates autophagy, was activated, whereas the ERK1/2 pathway, a positive regulator of autophagy, was inhibited. Accordingly, MEK inhibition by PD98059 sensitized glioma cells to dl922-947 effects, whereas autophagy induction by rapamycin protected cells from dl922-947-induced death. Treatment with two inhibitors of autophagy, chloroquine and 3-methyladenine, increased the cytotoxic effects of dl922-947 in vitro. In vivo, the growth of U87MG-induced xenografts was further reduced by adding chloroquine to the dl922-947 treatment. In conclusion, autophagy acts as a survival response in glioma cells infected with dl922-947, thus suggesting autophagy inhibitors as adjuvant/neoadjuvant drugs in oncolytic virus-based treatments.

AZD1152 negatively affects the growth of anaplastic thyroid carcinoma cells and enhances the effects of oncolytic virus dl922-947.

Novel therapeutic approaches are required for the treatment of anaplastic thyroid carcinoma (ATC), an incurable disease resistant to current available therapies. Aurora B is an important mitotic kinase involved in chromosome segregation and cytokinesis. It is overexpressed in many cancers including ATC and represents a potential target for chemotherapy. The effects of AZD1152, a specific Aurora B kinase inhibitor, have been evaluated against ATC, showing G(2)/M accumulation, polyploidy and subsequent cell death by mitotic catastrophe upon drug treatment. Only three administrations of AZD1152 significantly reduced the growth of ATC tumour xenogratfs. Oncolytic viruses in association with other forms of treatment have proven highly promising in preclinical and clinical reports. The oncolytic adenovirus dl922-947 is active against ATC cells, and we have evaluated the effects of the association between AZD1152 and dl922-947. In cells treated with virus and drug, we report additive/synergistic killing effects. Interestingly, the phosphorylation of histone H3 (Ser10), the main Aurora B substrate, is inhibited by dl922-947 in a dose-dependent manner, and completely abolished in association with AZD1152. The combined treatment significantly inhibited the growth of ATC tumour xenografts with respect to single treatments. Our data demonstrate that the Aurora B inhibitor AZD1152, alone or in combination with oncolytic virus dl922-947, could represent a novel therapeutic option for the treatment of ATC.