RNAi Knockdown of in Maternal Expression of Prader-Willi Syndrome Genes.

Background/objectives: Euchromatic histone lysine methyltransferase 2 (EHMT2, also known as G9a) is a mammalian histone methyltransferase that catalyzes the dimethylation of histone 3 lysine 9 (H3K9). On human chromosome 15, the parental-specific expression of Prader-Willi Syndrome (PWS)-related genes, such as and , are regulated through the genetic imprinting of the PWS imprinting center (PWS-IC). On the paternal allele, PWS genes are expressed whereas the epigenetic maternal silencing of PWS genes is controlled by the EHMT2-mediated methylation of H3K9 in PWS-IC.

CNS-dominant human FMRP isoform rescues seizures, fear, and sleep abnormalities in Fmr1-KO mice.

Fragile X syndrome is a neurodevelopmental disorder caused by the absence of the mRNA-binding protein fragile X messenger ribonucleoprotein (FMRP). Because FMRP is a highly pleiotropic protein controlling the expression of hundreds of genes, viral vector-mediated gene replacement therapy is viewed as a potential viable treatment to correct the fundamental underlying molecular pathology inherent in the disorder. Here, we studied the safety profile and therapeutic effects of a clinically relevant dose of a self-complementary adeno-associated viral (AAV) vector containing a major human brain isoform of FMRP after intrathecal injection into wild-type and fragile X-KO mice.

Minimum Effective Dose to Achieve Biochemical Correction with Adeno-Associated Virus Vector-Mediated Gene Therapy in Mice with Pompe Disease.

Pompe disease is an autosomal recessive lysosomal storage disorder caused by deficiency of acid α-glucosidase (GAA), resulting in skeletal muscle weakness and cardiomyopathy. Muscle weakness progresses despite currently available therapy, which has prompted the development of gene therapy with adeno-associated virus (AAV) type 2 vectors cross-packaged as AAV8 (2/8). Preclinical studies of gene therapy demonstrated that the minimum effective dose (MED) for biochemical correction with AAV2/8-LSPhGAA was ∼2 × 10 vector genomes (vg)/kg body weight.

Pathogenesis of Hepatic Tumors following Gene Therapy in Murine and Canine Models of Glycogen Storage Disease.

Glycogen storage disease type Ia (GSD Ia) is caused by mutations in the glucose-6-phosphatase (G6Pase) catalytic subunit gene (). GSD Ia complications include hepatocellular adenomas (HCA) with a risk for hepatocellular carcinoma (HCC) formation. Genome editing with adeno-associated virus (AAV) vectors containing a zinc-finger nuclease (ZFN) and a donor transgene was evaluated in adult mice with GSD Ia.

Fenofibrate rapidly decreases hepatic lipid and glycogen storage in neonatal mice with glycogen storage disease type Ia.

Glycogen storage disease type Ia (GSD Ia) is caused by autosomal mutations in glucose-6-phosphatase α catalytic subunit (G6PC) and can present with severe hypoglycemia, lactic acidosis and hypertriglyceridemia. In both children and adults with GSD Ia, there is over-accumulation of hepatic glycogen and triglycerides that can lead to steatohepatitis and a risk for hepatocellular adenoma or carcinoma. Here, we examined the effects of the commonly used peroxisomal proliferated activated receptor α agonist, fenofibrate, on liver and kidney autophagy and lipid metabolism in 5-day-old G6pc -/- mice serving as a model of neonatal GSD Ia.

NLRP12 Regulates Anti-viral RIG-I Activation via Interaction with TRIM25.

Establishing the balance between positive and negative innate immune mechanisms is crucial for maintaining homeostasis. Here we uncover the regulatory crosstalk between two previously unlinked innate immune receptor families: RIG-I, an anti-viral cytosolic receptor activated type I interferon production, and NLR (nucleotide-binding domain, leucine repeat domain-containing protein). We show that NLRP12 dampens RIG-I-mediated immune signaling against RNA viruses by controlling RIG-I's association with its adaptor MAVS.

Bezafibrate Enhances AAV Vector-Mediated Genome Editing in Glycogen Storage Disease Type Ia.

Glycogen storage disease type Ia (GSD Ia) is a rare inherited disease caused by mutations in the glucose-6-phosphatase (G6Pase) catalytic subunit gene (). Absence of G6Pase causes life-threatening hypoglycemia and long-term complications because of the accumulations of metabolic intermediates. Bezafibrate, a pan-peroxisome proliferator-activated receptor (PPAR) agonist, was administered in the context of genome editing with a zinc-finger nuclease-containing vector (AAV-ZFN) and a G6Pase donor vector (AAV-RoG6P).

BST2 inhibits infection of influenza A virus by promoting apoptosis of infected cells.

BST2 is an antiviral factor that inhibits the release of enveloped virus at the plasma membrane via an unusual topology in which its N-terminal is in the cytosol while its C-terminal is anchored by glycophosphatidylinositol (GPI). BST2-deficient cells showed substantially higher release of virions than wild type cells. Influenza-infected BST2-deficient cells showed greatly reduced cytopathic effect (CPE) than wild type cells despite their generally robust virus production.

Structure-based mechanism of action of a viral poly(ADP-ribose) polymerase 1-interacting protein facilitating virus replication.

Poly(ADP-ribose) polymerase 1 (PARP-1), an enzyme that modifies nuclear proteins by poly(ADP-ribosyl)ation, regulates various cellular activities and restricts the lytic replication of oncogenic gammaherpesviruses by inhibiting the function of replication and transcription activator (RTA), a key switch molecule of the viral life cycle. A viral PARP-1-interacting protein (vPIP) encoded by murine gammaherpesvirus 68 (MHV-68) facilitates lytic replication by disrupting interactions between PARP-1 and RTA. Here, the structure of MHV-68 vPIP was determined at 2.

A DNA-sensing-independent role of a nuclear RNA helicase, DHX9, in stimulation of NF-κB-mediated innate immunity against DNA virus infection.

DExD/H-box helicase 9 (DHX9), or RNA helicase A (RHA), is an abundant multifunctional nuclear protein. Although it was previously reported to act as a cytosolic DNA sensor in plasmacytoid dendritic cells (pDCs), the role and molecular mechanisms of action of DHX9 in cells that are not pDCs during DNA virus infection are not clear. Here, a macrophage-specific knockout and a fibroblast-specific knockdown of DHX9 impaired antiviral innate immunity against DNA viruses, leading to increased virus replication.

Correction: Influenza A Virus NS1 Protein Inhibits the NLRP3 Inflammasome.

[This corrects the article DOI: 10.1371/journal.pone.

The structure of the pleiotropic transcription regulator CodY provides insight into its GTP-sensing mechanism.

GTP and branched-chain amino acids (BCAAs) are metabolic sensors that are indispensable for the determination of the metabolic status of cells. However, their molecular sensing mechanism remains unclear. CodY is a unique global transcription regulator that recognizes GTP and BCAAs as specific signals and affects expression of more than 100 genes associated with metabolism.

Downregulation of Poly(ADP-Ribose) Polymerase 1 by a Viral Processivity Factor Facilitates Lytic Replication of Gammaherpesvirus.

Unlabelled: In Kaposi's sarcoma-associated herpesvirus (KSHV), poly(ADP-ribose) polymerase 1 (PARP-1) acts as an inhibitor of lytic replication. Here, we demonstrate that KSHV downregulated PARP-1 upon reactivation. The viral processivity factor of KSHV (PF-8) interacted with PARP-1 and was sufficient to degrade PARP-1 in a proteasome-dependent manner; this effect was conserved in murine gammaherpesvirus 68.

Influenza A Virus NS1 Protein Inhibits the NLRP3 Inflammasome.

The inflammasome is a molecular platform that stimulates the activation of caspase-1 and the processing of pro-interleukin (IL)-1β and pro-IL-18 for secretion. The NOD-like receptor family, pyrin domain containing 3 (NLRP3) protein is activated by diverse molecules and pathogens, leading to the formation of the NLRP3 inflammasome. Recent studies showed that the NLRP3 inflammasome mediates innate immunity against influenza A virus (IAV) infection.

Phosphatidylinositol-3-kinase and Akt are required for RIG-I-mediated anti-viral signalling through cross-talk with IPS-1.

Retinoic acid-inducible gene I (RIG-I) is a cytosolic pattern-recognition receptor that recognizes viruses and triggers anti-viral immune responses. Activation of intracellular RIG-I signalling is mediated through interferon-β (IFN-β) promoter stimulator-1 (IPS-1), an adaptor of RIG-I, which induces IFN regulatory factor (IRF) 3 activation and type I IFN expression. The phosphatidylinositol-3-kinase (PI3K) and Akt pathway is activated in host immune cells upon viral infection.

Murine gammaherpesvirus 68 encoding open reading frame 11 targets TANK binding kinase 1 to negatively regulate the host type I interferon response.

Unlabelled: Upon viral infection, type I interferons, such as alpha and beta interferon (IFN-α and IFN-β, respectively), are rapidly induced and activate multiple antiviral genes, thereby serving as the first line of host defense. Many DNA and RNA viruses counteract the host interferon system by modulating the production of IFNs. In this study, we report that murine gammaherpesvirus 68 (MHV-68), a double-stranded DNA virus, encodes open reading frame 11 (ORF11), a novel immune modulator, to block IFN-β production.

Antiviral activity of angelicin against gammaherpesviruses.

Human gammaherpesviruses including Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV) are important pathogens as they persist in the host and cause various malignancies. However, few antiviral drugs are available to efficiently control gammaherpesvirus replication. Here we identified the antiviral activity of angelicin against murine gammaherpesvirus 68 (MHV-68), genetically and biologically related to human gammaherpesviruses.

Early estrogen-induced gene 1, a novel RANK signaling component, is essential for osteoclastogenesis.

The receptor activator of NF-κB (RANK) and immunoreceptor tyrosine-based activation motif (ITAM)-containing adaptors are essential factors involved in regulating osteoclast formation and bone remodeling. Here, we identify early estrogen-induced gene 1 (EEIG1) as a novel RANK ligand (RANKL)-inducible protein that physically interacts with RANK and further associates with Gab2, PLCγ2 and Tec/Btk kinases upon RANKL stimulation. EEIG1 positively regulates RANKL-induced osteoclast formation, likely due to its ability to facilitate RANKL-stimulated PLCγ2 phosphorylation and NFATc1 induction.

Persistent infection of a gammaherpesvirus in the central nervous system.

Human gammaherpesvirus infections of the central nervous system (CNS) have been linked to various neurological diseases. Murine gammaherpesvirus 68 (MHV-68), genetically related and biologically similar to human gammaherpesviruses, infects the CNS in laboratory mice. However, viral persistency of MHV-68 has not been studied following CNS infection.

The virion-associated open reading frame 49 of murine gammaherpesvirus 68 promotes viral replication both in vitro and in vivo as a derepressor of RTA.

Replication and transcription activator (RTA), an immediate-early gene, is a key molecular switch to evoke lytic replication of gammaherpesviruses. Open reading frame 49 (ORF49) is conserved among gammaherpesviruses and shown to cooperate with RTA in regulating virus lytic replication. Here we show a molecular mechanism and in vivo functions of murine gammaherpesvirus 68 (MHV-68 or γHV-68) ORF49.