Biallelic variants in LIG3 cause a novel mitochondrial neurogastrointestinal encephalomyopathy

none67si: Abnormal gut motility is a feature of several mitochondrial encephalomyopathies, and mutations in genes such as TYMP and POLG, have been linked to these rare diseases. The human genome encodes three DNA ligases, of which only one, ligase III (LIG3), has a mitochondrial splice variant and is crucial for mitochondrial health. We investigated the effect of reduced LIG3 activity and resulting mitochondrial dysfunction in seven patients from three independent families, who showed the common occurrence of gut dysmotility and neurological manifestations reminiscent of mitochondrial neurogastrointestinal encephalomyopathy. DNA from these patients was subjected to whole exome sequencing. In all patients, compound heterozygous variants in a new disease gene, LIG3, were identified. All variants were predicted to have a damaging effect on the protein. The LIG3 gene encodes the only mitochondrial DNA (mtDNA) ligase and therefore plays a pivotal role in mtDNA repair and replication. In vitro assays in patient-derived cells showed a decrease in LIG3 protein levels and ligase activity. We demonstrated that the LIG3 gene defects affect mtDNA maintenance, leading to mtDNA depletion without the accumulation of multiple deletions as observed in other mitochondrial disorders. This mitochondrial dysfunction is likely to cause the phenotypes observed in these patients. The most prominent and consistent clinical signs were severe gut dysmotility and neurological abnormalities, including leukoencephalopathy, epilepsy, migraine, stroke-like episodes, and neurogenic bladder. A decrease in the number of myenteric neurons, and increased fibrosis and elastin levels were the most prominent changes in the gut. Cytochrome c oxidase (COX) deficient fibres in skeletal muscle were also observed. Disruption of lig3 in zebrafish reproduced the brain alterations and impaired gut transit in vivo. In conclusion, we identified variants in the LIG3 gene that result in a mitochondrial disease characterized by predominant gut dysmotility, encephalopathy, and neuromuscular abnormalities.This work was supported by Telethon Grant GGP15171 to E.B. and R.D.G. and by a donation from Kobe city to the Department of General Pediatrics, Kobe University Graduate School of Medicine (K550003302). S.C. was supported by a Dutch Cancer Foundation grant (KWF11011). V.C. and A.M. were supported by the Italian Ministry of Health (“Ricerca Corrente” funding). R.D.G. is the recipient of grants from University of Ferrara (FAR and FIR funds).openBonora, Elena; Chakrabarty, Sanjiban; Kellaris, Georgios; Tsutsumi, Makiko; Bianco, Francesca; Bergamini, Christian; Ullah, Farid; Isidori, Federica; Liparulo, Irene; Diquigiovanni, Chiara; Masin, Luca; Rizzardi, Nicola; Cratere, Mariapia Giuditta; Boschetti, Elisa; Papa, Valentina; Maresca, Alessandra; Cenacchi, Giovanna; Casadio, Rita; Martelli, Pierluigi; Matera, Ivana; Ceccherini, Isabella; Fato, Romana; Raiola, Giuseppe; Arrigo, Serena; Signa, Sara; Sementa, Angela Rita; Severino, Mariasavina; Striano, Pasquale; Fiorillo, Chiara; Goto, Tsuyoshi; Uchino, Shumpei; Oyazato, Yoshinobu; Nakamura, Hisayoshi; Mishra, Sushil K; Yeh, Yu-Sheng; Kato, Takema; Nozu, Kandai; Tanboon, Jantima; Morioka, Ichiro; Nishino, Ichizo; Toda, Tatsushi; Goto, Yu-Ichi; Ohtake, Akira; Kosaki, Kenjiro; Yamaguchi, Yoshiki; Nonaka, Ikuya; Iijima, Kazumoto; Mimaki, Masakazu; Kurahashi, Hiroki; Raams, Anja; MacInnes, Alyson; Alders, Mariel; Engelen, Marc; Linthorst, Gabor; de Koning, Tom; den Dunnen, Wilfred; Dijkstra, Gerard; van Spaendonck, Karin; van Gent, Dik C; Aronica, Eleonora M; Picco, Paolo; Carelli, Valerio; Seri, Marco; Katsanis, Nicholas; Duijkers, Floor A M; Taniguchi-Ikeda, Mariko; De Giorgio, RobertoBonora, Elena; Chakrabarty, Sanjiban; Kellaris, Georgios; Tsutsumi, Makiko; Bianco, Francesca; Bergamini, Christian; Ullah, Farid; Isidori, Federica; Liparulo, Irene; Diquigiovanni, Chiara; Masin, Luca; Rizzardi, Nicola; Cratere, Mariapia Giuditta; Boschetti, Elisa; Papa, Valentina; Maresca, Alessandra; Cenacchi, Giovanna; Casadio, Rita; Martelli, Pierluigi; Matera, Ivana; Ceccherini, Isabella; Fato, Romana; Raiola, Giuseppe; Arrigo, Serena; Signa, Sara; Sementa, Angela Rita; Severino, Mariasavina; Striano, Pasquale; Fiorillo, Chiara; Goto, Tsuyoshi; Uchino, Shumpei; Oyazato, Yoshinobu; Nakamura, Hisayoshi; Mishra, Sushil K; Yeh, Yu-Sheng; Kato, Takema; Nozu, Kandai; Tanboon, Jantima; Morioka, Ichiro; Nishino, Ichizo; Toda, Tatsushi; Goto, Yu-Ichi; Ohtake, Akira; Kosaki, Kenjiro; Yamaguchi, Yoshiki; Nonaka, Ikuya; Iijima, Kazumoto; Mimaki, Masakazu; Kurahashi, Hiroki; Raams, Anja; MacInnes, Alyson; Alders, Mariel; Engelen, Marc; Linthorst, Gabor; de Koning, Tom; den Dunnen, Wilfred; Dijkstra, Gerard; van Spaendonck, Karin; van Gent, Dik C; Aronica, Eleonora M; Picco, Paolo; Carelli, Valerio; Seri, Marco; Katsanis, Nicholas; Duijkers, Floor A M; Taniguchi-Ikeda, Mariko; De Giorgio, Robert

Lower HIV Provirus Levels Are Associated with More APOBEC3G Protein in Blood Resting Memory CD4+ T Lymphocytes of Controllers <i>In Vivo</i>

<div><p>Immunodeficiency does not progress for prolonged periods in some HLA B57- and/or B27-positive subjects with human immunodeficiency virus type 1 (HIV) infection, even in the absence of antiretroviral therapy (ART). These “controllers” have fewer HIV provirus-containing peripheral blood mononuclear cells than “non-controller” subjects, but lymphocytes that harbor latent proviruses were not specifically examined in studies to date. Provirus levels in resting memory cells that can serve as latent reservoirs of HIV in blood were compared here between controllers and ART-suppressed non-controllers. APOBEC3G (A3G), a cellular factor that blocks provirus formation at multiple steps if not antagonized by HIV virion infectivity factor (Vif), was also studied. HLA-linked HIV control was associated with less provirus and more A3G protein in resting CD4+ T central memory (Tcm) and effector memory (Tem) lymphocytes (provirus: p = 0.01 for Tcm and p = 0.02 for Tem; A3G: p = 0.02 for Tcm and p = 0.02 for Tem). Resting memory T cells with the highest A3G protein levels (>0.5 RLU per unit of actin) had the lowest levels of provirus (<1,000 copies of DNA per million cells) <i>in vivo</i> (p = 0.03, Fisher's exact test). Using two different experimental approaches, Vif-positive viruses with more A3G were found to have decreased virion infectivity <i>ex vivo</i>. These results raise the hypothesis that HIV control is associated with increased cellular A3G that may be packaged into Vif-positive virions to add that mode of inhibition of provirus formation to previously described adaptive immune mechanisms for HIV control.</p></div

I marmi della chiesa di San Salvatore a Monopoli: analisi petrografica e tecniche esecutive.

Nella chiesa di San Salvatore in Monopoli (BA) sono presenti numerosi marmi policromi che nel secolo XVIII sono stati utilizzati dal marmoraro Aniello Gentile per impreziosire l’altare maggiore e le due acquasantiere del luogo di culto. I principali litotipi utilizzati, come da consuetudine della scuola dei marmorari napoletani, vedono la compresenza di tipologie marmoree estratte da cave di epoca barocca accanto a pregiati marmi antichi di riuso generalmente prelevati da edifici di epoca romana o bizantina

Higher cellular A3G protein levels were associated with decreased infectivity and spread of HIV virions after <i>ex vivo</i> activation and infection of primary memory T lymphocytes.

<p>(<b>A</b>) Blood resting CD4+ T central memory (Tcm) and effector memory (Tem) cells sorted from the same uninfected subject were activated and then infected <i>ex vivo</i> with a Vif-positive, CCR5-tropic clinical isolate of HIV. HIV p24 antigen was monitored over time in supernatant fluids from separate Tcm and Tem cell cultures. Virus spread through the culture of Tcm cells more rapidly than it did through the culture of Tem cells previously shown to have higher A3G protein levels (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0076002#pone-0076002-g002" target="_blank">Figure 2</a>). (<b>B</b>) Infectivity of virions produced from Tcm cells was greater than that of virions produced from Tem cells. Infectivity was quantified by luciferase activity normalized by amount of p24 antigen added to TZM-bl reporter cells. Bars represent mean +/− standard deviation (SD).</p

Virion-packaged A3G and infectivity of endogenous viruses produced from activated CD4+ T lymphocytes <i>ex vivo</i>.

<p>(<b>A</b>) Increased virion-packaged A3G protein was associated with decreased infectivity of endogenous viruses produced from activated CD4+ T lymphocytes. Virions released from activated CD4+ T lymphocytes of ART-suppressed (AS) non-controller subjects were analyzed for infectivity using the TZM-bl assay and for virion-associated A3G protein by in-virion Western blotting. CD4+ T lymphocytes were sorted for positivity for CD25, CD69, CD38 and HLA-DR from blood of 5 of the AS non-controller subjects. Activation was maintained in <i>ex vivo</i> cultures by anti-CD3/CD28 antibody coated beads. HIV-1 p24 antigen measurement monitored production of endogenous Vif-positive HIV-1 <i>ex vivo</i>. Virion content was normalized by p24 antigen amount for both infectivity and virion A3G protein measurements. Bars represent mean +/− standard deviation (SD). (<b>B</b>) Virion infectivity was significantly inversely correlated with amount of A3G protein in virions. P value was determined by Spearman correlation.</p

HIV provirus (A) and APOBEC3G protein (B) levels in blood resting CD4+ T memory lymphocytes.

<p>(<b>A</b>) Blood resting CD4+ T central memory (Tcm) and effector memory (Tem) cells from viremic controller (VC) subjects (n = 7) each had lower HIV provirus copy numbers than those cells from antiretroviral therapy suppressed (AS) non-controller subjects (n = 6). <i>Alu</i>-PCR was used to determine HIV provirus copy numbers, as log integrated copies per million cells. (<b>B</b>) Blood resting CD4+ Tcm and Tem cells from VC subjects (n = 4) each had higher APOBEC3G (A3G) protein levels than those cells from AS non-controller subjects (n = 4). Relative light units (RLU) of A3G bands on immunoblots were quantified using Licor Odyssey, with normalization to β-actin. Cells from which A3G protein levels were determined were from 8 of the same time points studied for each subject in Fig. 1(A) (4 for VC and 4 for AS subjects); protein quantitation was possible for only a subset of the subject cells/time points studied in Fig. 1(A). In (<b>A</b>) and (<b>B</b>), lines indicate median values. P values were determined by 2-tailed Mann-Whitney test.</p

Imerslund-GrÄsbeck syndrome and celiac disease: A strange but possible association

The paper describes the unusuala association of Imerslund-GrÄsbeck syndrome and celiac disease

Biallelic variants in LIG3 cause a novel mitochondrial neurogastrointestinal encephalomyopathy

Abnormal gut motility is a feature of several mitochondrial encephalomyopathies, and mutations in genes such as TYMP and POLG, have been linked to these rare diseases. The human genome encodes three DNA ligases, of which only one, ligase III (LIG3), has a mitochondrial splice variant and is crucial for mitochondrial health. We investigated the effect of reduced LIG3 activity and resulting mitochondrial dysfunction in seven patients from three independent families, who showed the common occurrence of gut dysmotility and neurological manifestations reminiscent of mitochondrial neurogastrointestinal encephalomyopathy. DNA from these patients was subjected to whole exome sequencing. In all patients, compound heterozygous variants in a new disease gene, LIG3, were identified. All variants were predicted to have a damaging effect on the protein. The LIG3 gene encodes the only mitochondrial DNA (mtDNA) ligase and therefore plays a pivotal role in mtDNA repair and replication. In vitro assays in patient-derived cells showed a decrease in LIG3 protein levels and ligase activity. We demonstrated that the LIG3 gene defects affect mtDNA maintenance, leading to mtDNA depletion without the accumulation of multiple deletions as observed in other mitochondrial disorders. This mitochondrial dysfunction is likely to cause the phenotypes observed in these patients. The most prominent and consistent clinical signs were severe gut dysmotility and neurological abnormalities, including leukoencephalopathy, epilepsy, migraine, stroke-like episodes, and neurogenic bladder. A decrease in the number of myenteric neurons, and increased fibrosis and elastin levels were the most prominent changes in the gut. Cytochrome c oxidase (COX) deficient fibres in skeletal muscle were also observed. Disruption of lig3 in zebrafish reproduced the brain alterations and impaired gut transit in vivo. In conclusion, we identified variants in the LIG3 gene that result in a mitochondrial disease characterized by predominant gut dysmotility, encephalopathy, and neuromuscular abnormalities