Hereditary fructose intolerance mimicking a biochemical phenotype of mucolipidosis: A review of the literature of secondary causes of lysosomal enzyme activity elevation in serum.

We describe a patient with failure to thrive, hepatomegaly, liver dysfunction, and elevation of multiple plasma lysosomal enzyme activities mimicking mucolipidosis II or III, in whom a diagnosis of hereditary fructose intolerance (HFI) was ultimately obtained. She presented before introduction of solid foods, given her consumption of a fructose-containing infant formula. We present the most extensive panel of lysosomal enzyme activities reported to date in a patient with HFI, and propose that multiple enzyme elevations in plasma, especially when in conjunction with a normal plasma α-mannosidase activity, should elicit a differential diagnosis of HFI. We also performed a review of the literature on the different etiologies of elevated lysosomal enzyme activities in serum or plasma. © 2016 Wiley Periodicals, Inc.

Identical Twins Discordant for Metopic Craniosynostosis: Evidence of Epigenetic Influences.

Craniosynostosis, or premature fusion of the cranial sutures, occurs in approximately 1 in 2500 live births. The genetic causes and molecular basis of these disorders have greatly expanded over the last 2 decades, with numerous causative and contributory mutations having been identified. The role of fibroblast growth factor receptor (FGFR) mutations in the etiology of certain eponymous forms of craniosynostosis is now well elucidated; the most common syndromes associated with craniosynostosis are Pfeifer (FGFR1, FGFR2), Apert (FGFR2), Crouzon (FGFR2), Saethre-Chotzen (TWIST1), Jackson-Weiss (FGFR2), Greig (GL13), and Muenke (FGFR3) syndromes. Although pathological expression of these mutations often results in bilateral coronal craniosynostosis, single suture fusions (typically unilateral coronal synostosis) or multiple suture craniosynostosis are possible.The majority of patients diagnosed with craniosynostosis lack an identifiable syndrome or genetic mutation. The etiopathogenesis of these "nonsyndromic" forms of craniosynostosis is believed to involve a complex interplay of genetics, epigenetics, and environmental factors. Evaluation of genes implicated in nonsyndromic craniosynostosis has been conflicting; some evidence demonstrates an interplay between genetic and epigenetic influences while others do not. Certain environmental factors such as teratogenic levels of retinoic acid, maternal metabolic and hematologic disorders, and head growth constraint in utero may increase the likelihood of developing craniosynostosis, but these associations are again tenuous.The authors present 1 of 2 genetically confirmed identical twins discordant for metopic craniosynostosis. The implications of this case are clear: epigenetic influences, environmental influences, or both played a role in the development of this premature suture fusion.

Comparison of the Life Cycles of Genetically Distant Species C and Species D Human Adenoviruses Ad6 and Ad26 in Human Cells.

UNLABELLED: Our understanding of adenovirus (Ad) biology is largely extrapolated from human species C Ad5. Most humans are immune to Ad5, so lower-seroprevalence viruses like human Ad6 and Ad26 are being tested as therapeutic vectors. Ad6 and Ad26 differ at the DNA level by 34%. To better understand how this might impact their biology, we examined the life cycle of the two viruses in human lung cells in vitro. Both viruses infected A549 cells with similar efficiencies, executed DNA replication with identical kinetics within 12 h, and began killing cells within 72 h. While Ad6-infected cells remained adherent until death, Ad26-infected cells detached within 12 h of infection but remained viable. Next-generation sequencing (NGS) of mRNA from infected cells demonstrated that viral transcripts constituted 1% of cellular mRNAs within 6 h and 8 to 16% within 12 h. Quantitative PCR and NGS revealed the activation of key early genes at 6 h and transition to late gene activation by 12 h by both viruses. There were marked differences in the balance of E1A and E1B activation by the two viruses and in the expression of E3 immune evasion mRNAs. Ad6 was markedly more effective at suppressing major histocompatibility complex class I (MHC I) display on the cell surface and in evading TRAIL-mediated apoptosis than was Ad26. These data demonstrate shared as well as divergent life cycles in these genetically distant human adenoviruses. An understanding of these differences expands the knowledge of alternative Ad species and may inform the selection of related Ads for therapeutic development. IMPORTANCE: A burgeoning number of adenoviruses (Ads) are being harnessed as therapeutics, yet the biology of these viruses is generally extrapolated from Ad2 and Ad5. Here, we are the first to compare the transcriptional programs of two genetically distant Ads by mRNA next-generation sequencing (NGS). Species C Ad6 and Ad26 are being pursued as lower-seroprevalence Ad vectors but differ at the DNA level by 34%. Head-to-head comparison in human lung cells by NGS revealed that the two viruses generally conform to our general understanding of the Ad transcriptional program. However, fine mapping revealed subtle and strong differences in how these two viruses execute these programs, including differences in the balance of E1A and E1B mRNAs and in E3 immune evasion genes. This suggests that not all adenoviruses behave like Ad2 and Ad5 and that they may have unique strategies to infect cells and evade the immune system.

A clinicopathologic study of diencephalic pediatric low-grade gliomas with BRAF V600 mutation.

Among brain tumors, the BRAF (V600E) mutation is frequently associated with pleomorphic xanthoastrocytomas (PXAs) and gangliogliomas (GGs). This oncogenic mutation is also detected in ~5 % of other pediatric low-grade gliomas (LGGs) including pilocytic astrocytomas (PAs) and diffuse astrocytomas. In the current multi-institutional study of 56 non-PXA/non-GG diencephalic pediatric LGGs, the BRAF (V600) mutation rate is 36 %. V600-mutant tumors demonstrate a predilection for infants and young children (

Generation of a hypomorphic model of propionic acidemia amenable to gene therapy testing.

Propionic acidemia (PA) is a recessive genetic disease that results in an inability to metabolize certain amino acids and odd-chain fatty acids. Current treatment involves restricting consumption of these substrates or liver transplantation. Deletion of the Pcca gene in mice mimics the most severe forms of the human disease. Pcca(-) mice die within 36 hours of birth, making it difficult to test intravenous systemic therapies in them. We generated an adult hypomorphic model of PA in Pcca(-) mice using a transgene bearing an A138T mutant of the human PCCA protein. Pcca(-/-)(A138T) mice have 2% of wild-type PCC activity, survive to adulthood, and have elevations in propionyl-carnitine, methylcitrate, glycine, alanine, lysine, ammonia, and markers associated with cardiomyopathy similar to those in patients with PA. This adult model allowed gene therapy testing by intravenous injection with adenovirus serotype 5 (Ad5) and adeno-associated virus 2/8 (AAV8) vectors. Ad5-mediated more rapid increases in PCCA protein and propionyl-CoA carboxylase (PCC) activity in the liver than AAV8 and both vectors reduced propionylcarnitine and methylcitrate levels. Phenotypic correction was transient with first generation Ad whereas AAV8-mediated long-lasting effects. These data suggest that this PA model may be a useful platform for optimizing systemic intravenous therapies for PA.

Efficient production of Fah-null heterozygote pigs by chimeric adeno-associated virus-mediated gene knockout and somatic cell nuclear transfer.

UNLABELLED: Hereditary tyrosinemia type I (HT1) results in hepatic failure, cirrhosis, and hepatocellular carcinoma (HCC) early in childhood and is caused by a deficiency in the enzyme fumarylacetoacetate hydrolase (FAH). In a novel approach we used the chimeric adeno-associated virus DJ serotype (AAV-DJ) and homologous recombination to target and disrupt the porcine Fah gene. AAV-DJ is an artificial chimeric AAV vector containing hybrid capsid sequences from three naturally occurring serotypes (AAV2, 8, and 9). The AAV-DJ vector was used to deliver the knockout construct to fetal pig fibroblasts with an average knockout targeting frequency of 5.4%. Targeted Fah-null heterozygote fibroblasts were used as nuclear donors for somatic cell nuclear transfer (SCNT) to porcine oocytes and multiple viable Fah-null heterozygote pigs were generated. Fah-null heterozygotes were phenotypically normal, but had decreased Fah transcriptional and enzymatic activity compared to wildtype animals. CONCLUSION: This study is the first to use a recombinant chimeric AAV vector to knockout a gene in porcine fibroblasts for the purpose of SCNT. In using the AAV-DJ vector we observed targeting frequencies that were higher than previously reported with other naturally occurring serotypes. We expect that the subsequent generation of FAH-null homozygote pigs will serve as a significant advancement for translational research in the areas of metabolic liver disease, cirrhosis, and HCC.

Clinical diagnostic testing for the cytogenetic and molecular causes of male infertility: the Mayo Clinic experience.

PURPOSE: Approximately 8% of couples attempting to conceive are infertile and male infertility accounts for approximately 50% of infertility among couples. Up to 25% of males with non-obstructive infertility have chromosomal abnormalities and/or microdeletions of the long arm of the Y-chromosome. These are detected by conventional chromosome and Y-microdeletion analysis. In this study, we reviewed the results of testing performed in the Mayo Clinic Cytogenetics and Molecular Genetics Laboratories and compared our findings with previously published reports. METHODS: This study includes 2,242 chromosome studies from males ≥18 years of age referred for infertility between 1989 and 2000 and 2,749 Y-deletion molecular studies performed between 2002 and 2009. RESULTS: 14.3% of infertile males tested by karyotyping had abnormalities identified. These include: (258) 47,XXY and variants consistent with Klinefelter syndrome, (3) combined 47,XXY and balanced autosomal rearrangements, (9) 47,XYY, (9) Y-deletions, (7) 46,XX males, (32) balanced rearrangements, and (1) unbalanced rearrangement. 3.6% of males tested for Y-microdeletion analysis had abnormalities identified, 90% of which included a deletion of the AZFc region. CONCLUSIONS: This study highlights the need of males suffering from non-obstructive infertility to have laboratory genetic testing performed. An abnormal finding can have significant consequences to assisted reproductive techniques and fertility treatment, and provide a firm diagnosis to couples with longstanding infertility.

Adenovirus activates complement by distinctly different mechanisms in vitro and in vivo: indirect complement activation by virions in vivo.

Understanding innate immunity is key to improving the safety of adenovirus (Ad) vectors for systemic gene therapy. Ad has been shown to activate complement in vitro, but activation of complement after Ad injection in vivo has not been directly measured. Using complement protein C3a as a marker of complement activation, we show that types 2 and 5 human Ads cause rapid complement activation after intravenous injection in mice. Unexpectedly, the mechanisms in vivo were different than those in vitro. Antibodies were critical for the activation of complement by Ad in vitro, but antibodies were not required in vivo. The classical pathway was required in vitro, whereas complement activation in vivo involved both classical and nonclassical pathways as well as the reticuloendothelial system. Remarkably, the entry-deficient Ad mutant ts1 was completely unable to activate complement in vivo even though it was fully able to activate complement in vitro. This result demonstrates that the complement system senses intravenously injected Ad primarily by detecting the effects of Ad on cells rather than through direct interaction of complement with virions. Encouragingly, shielding Ad with polyethylene glycol was effective at reducing complement activation both in vitro and in vivo. In summary, intravenously injected Ad rapidly activates complement through multiple pathways, but these pathways are different than those identified by in vitro studies. In vitro studies are poorly predictive of in vivo mechanisms because Ad virions activate complement through indirect mechanisms in vivo.

Modification of adenoviral vectors with polyethylene glycol modulates in vivo tissue tropism and gene expression.

Polyethylene glycol (PEG) is a hydrophilic polymer that has been used to coat adenoviral (Ad) vectors to improve their pharmacology. To analyze the effects of PEG on Ad5 tropism, Ad5 was covalently modified with different sizes of PEG and in vitro and in vivo transduction was analyzed. All tested PEGs ablated in vitro transduction. When protein C (PC) and factors VII, IX, and X were added, only factors IX and X increased transduction by the PEGylated vectors with the largest effect by X. Inactivation of these factors with warfarin drastically reduced liver transduction in mice by the PEGylated vectors after intravenous (i.v.) injection. Ad5 conjugated with 5 kd PEG maintained normal liver transduction while conjugation with larger 20 and 35 kd PEGs significantly reduced liver transduction. When intraperitoneal (i.p.) injection was tested, Ad transduced the peritoneum efficiently with only low level liver transduction. When Ad5 was modified with 5 kd PEG, peritoneal transduction was reduced and the virus preferentially transduced the liver. These data demonstrate the effects of different sizes of PEG on in vivo Ad tropism and suggest that this approach may be useful in retargeting and detargeting Ad in vivo.

Polyethylene glycol modification of adenovirus reduces platelet activation, endothelial cell activation, and thrombocytopenia.

Thrombocytopenia is one of the complications for in vivo administration of adenovirus serotype 5 (Ad5) vectors after intravenous injection. In this paper, we investigated the mechanism of Ad5-induced thrombocytopenia and how these effects are attenuated by polyethylene glycol (PEG) modification of Ad5 (Ad-PEG). After intravenous injection, accelerated platelet loss was observed in Ad-injected mice but not in their Ad-PEG-injected counterparts. This platelet loss induced by Ad5 corresponded with increases in coagulation D-dimer levels, splenomegaly, and, later, production of megakaryocytes in the bone marrow. In contrast, these responses were blunted or ablated after injection of Ad-PEG. Ad5 activated both platelets and endothelial cells directly in vitro as evidenced by induction of P-selectin and the formation of von Willebrand factor-platelet strings and in vivo as evidenced by the induction of E-selectin messenger RNA. PEGylation blunted these observed activations. These data suggest that Ad5 may induce thrombocytopenia by direct activation of endothelial cells in addition to its direct effects on platelets. This link provides an important clue for the understanding of the mechanisms of thrombocytopenia associated with Ad5. Given that PEGylation blunted interactions of Ad with platelets and endothelial cells, reduced D-dimer formation, reduced thrombocytopenia, and reduced splenomegaly, these data suggest that this simple vector modification may have utility to improve the safety of Ad vectors for human gene therapy.

Adeno-associated virus serotype 8 gene transfer rescues a neonatal lethal murine model of propionic acidemia.

Propionic acidemia (PA) is an autosomal recessive disorder of metabolism caused by a deficiency of propionyl-coenzyme A carboxylase (PCC). Despite optimal dietary and cofactor therapy, PA patients still suffer from lethal metabolic instability and experience multisystemic complications. A murine model of PA (Pcca(-/-)) of animals that uniformly die within the first 48 hr of life was used to determine the efficacy of adeno-associated viral (AAV) gene transfer as a potential therapy for PA. An AAV serotype 8 (AAV8) vector was engineered to express the human PCCA cDNA and delivered to newborn mice via an intrahepatic injection. Greater than 64% of the Pcca(-/-) mice were rescued after AAV8-mediated gene transfer and survived until day of life 16 or beyond. Western analysis of liver extracts showed that PCC was completely absent from Pcca(-/-) mice but was restored to greater than wild-type levels after AAV gene therapy. The treated Pcca(-/-) mice also exhibited markedly reduced plasma levels of 2-methylcitrate compared with the untreated Pcca(-/-) mice, which indicates significant PCC enzymatic activity was provided by gene transfer. At the time of this report, the oldest treated Pcca(-/-) mice are over 6 months of age. In summary, AAV gene delivery of PCCA effectively rescues Pcca(-/-) mice from neonatal lethality and substantially ameliorates metabolic markers of the disease. These experiments demonstrate a gene transfer approach using AAV8 that might be used as a treatment for PA, a devastating and often lethal disorder desperately in need of new therapeutic options.

Real-time dynamic imaging of virus distribution in vivo.

The distribution of viruses and gene therapy vectors is difficult to assess in a living organism. For instance, trafficking in murine models can usually only be assessed after sacrificing the animal for tissue sectioning or extraction. These assays are laborious requiring whole animal sectioning to ascertain tissue localization. They also obviate the ability to perform longitudinal or kinetic studies in one animal. To track viruses after systemic infection, we have labeled adenoviruses with a near-infrared (NIR) fluorophore and imaged these after intravenous injection in mice. Imaging was able to track and quantitate virus particles entering the jugular vein simultaneous with injection, appearing in the heart within 500 milliseconds, distributing in the bloodstream and throughout the animal within 7 seconds, and that the bulk of virus distribution was essentially complete within 3 minutes. These data provide the first in vivo real-time tracking of the rapid initial events of systemic virus infection.

Rescue, amplification, purification, and PEGylation of replication defective first-generation adenoviral vectors.

Adenoviral gene therapy vectors have been widely studied and used. Their extremely high transduction efficiency and gene delivery in vivo make them attractive for cancer gene therapy approaches. While they are robust, they are also very immunogenic. One approach to mitigate the immunogenicity of adenoviruses and to evade neutralizing antibodies is to coat the virus with the hydrophilic polymer polyethylene glycol (PEG) (1). This chapter details the steps involved when going from recombinant adenoviral vector plasmid all the way to validated PEGylated adenovirus product.

Chemical modification with high molecular weight polyethylene glycol reduces transduction of hepatocytes and increases efficacy of intravenously delivered oncolytic adenovirus.

Oncolytic adenoviruses are anticancer agents that replicate within tumors and spread to uninfected tumor cells, amplifying the anticancer effect of initial transduction. We tested whether coating the viral particle with polyethylene glycol (PEG) could reduce transduction of hepatocytes and hepatotoxicity after systemic (intravenous) administration of oncolytic adenovirus serotype 5 (Ad5). Conjugating Ad5 with high molecular weight 20-kDa PEG but not with 5-kDa PEG reduced hepatocyte transduction and hepatotoxicity after intravenous injection. PEGylation with 20-kDa PEG was as efficient at detargeting adenovirus from Kupffer cells and hepatocytes as virus predosing and warfarin. Bioluminescence imaging of virus distribution in two xenograft tumor models in nude mice demonstrated that PEGylation with 20-kDa PEG reduced liver infection 19- to 90-fold. Tumor transduction levels were similar for vectors PEGylated with 20-kDa PEG and unPEGylated vectors. Anticancer efficacy after a single intravenous injection was retained at the level of unmodified vector in large established prostate carcinoma xenografts, resulting in complete elimination of tumors in all animals and long-term tumor-free survival. Anticancer efficacy after a single intravenous injection was increased in large established hepatocellular carcinoma xenografts, resulting in significant prolongation of survival as compared with unmodified vector. The increase in efficacy was comparable to that obtained with predosing and warfarin pretreatment, significantly extending the median of survival. Shielding adenovirus with 20-kDa PEG may be a useful approach to improve the therapeutic window of oncolytic adenovirus after systemic delivery to primary and metastatic tumor sites.

Systemic delivery of therapeutic viruses.

The treatment of certain diseases will require the systemic delivery of therapeutic genes or viruses. In most cases, intravascular injection is the best delivery method to achieve the systemic distribution of viruses and to enable these agents to reach distant therapeutic sites. However, viruses administered by intravascular injection encounter overlapping barriers that impede their ability to reach their targets, including interactions with blood cells, blood factors and endothelial cells, loss to hepatocytes and macrophages, and destruction by innate and adaptive immune responses. In this review, recent advances in the understanding of the mechanisms determining virus tropism following systemic administration and the pharmacology of therapeutic viruses are described. Adenoviruses are used as a paradigm of these interactions, and factors affecting their therapeutic efficacy and side effects are discussed, as well as how the barriers that impede their ability to reach their targets translate to other therapeutic viruses.

Short-term rescue of neonatal lethality in a mouse model of propionic acidemia by gene therapy.

Propionic acidemia (PA) is a metabolic disorder that causes mental retardation and that can be fatal if untreated. PA is inherited in an autosomal recessive fashion involving mutations in PCCA or PCCB encoding the alpha and beta subunits of propionyl-CoA carboxylase (PCC). Current treatment is based on dietary restriction of substrate amino acids, which attenuates symptoms. However, patients still experience episodes of hyperammonemia that can cause progressive neurologic damage. In this paper, we have tested gene therapy approaches to PA in a stringent mouse model of PCCA deficiency, in which homozygous knockout mice are born but die within 36 hr. In this work, we have delivered first-generation and helper-dependent adenovirus serotype 5 (Ad5) vectors expressing the human PCCA cDNA by intraperitoneal injection into newborn mice. Unmodified Ad5 vectors mediated extensive transduction of the peritoneum with weak liver transduction as determined by luciferase imaging and dsRed expression. In contrast, modification of Ad5 with polyethylene glycol detargeted the virus from the peritoneum and retargeted it for transduction in the liver. When vectors expressing PCCA were injected, significant increases in life span were observed for both the unmodified and polyethylene glycol (PEG)-modified Ad5 vectors. However, this rescue was transient. Similarly, adeno-associated virus serotype 8-mediated transduction also produced only transient rescue. These data show first proof of principle for gene therapy of PA and demonstrate the potential utility of PEG to modify viral tropism in an actual gene therapy application.