Human Molecular Genetics (HUM MOL GENET )

Publisher: Oxford University Press

Description

Human Molecular Genetics concentrates on full-length research papers covering a wide range of topics in all aspects of human molecular genetics. These include: the molecular basis of human genetic disease developmental genetics neurogenetics chromosome structure and function molecular aspects of cancer genetics gene therapy biochemical genetics major advances in gene mapping understanding of genome organisation In addition the journal also publishes research on other model systems for the analysis of genes especially when there is an obvious relevance to human genetics. Key features of the journal include: Articles - comprehensive reports and definitive research findings of interest to a broad audience of human molecular geneticists. We encourage inclusion of full experimental details with as many display items (figures and tables) as required to tell the complete story. Reports - descriptions of novel results of biological and genetic importance in the field. Commentaries - these discuss recent papers in the journal or review areas of particular interest in the field. Now in its eighth year of publication Human Molecular Genetics has clearly become one of the leading journals in this exciting frontier of scientific research. With the enthusiastic support of the executive editors and editorial board we intend to ensure that the journal's reputation for quality is reinforced in the years to come.

Impact factor 6.68

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    Impact factor
  • 5-year impact
    7.54
  • Cited half-life
    6.60
  • Immediacy index
    1.55
  • Eigenfactor
    0.11
  • Article influence
    3.08
  • Website
    Human Molecular Genetics website
  • Other titles
    Human molecular genetics
  • ISSN
    0964-6906
  • OCLC
    25594670
  • Material type
    Periodical, Internet resource
  • Document type
    Journal / Magazine / Newspaper, Internet Resource

Publisher details

Oxford University Press

  • Pre-print
    • Author can archive a pre-print version
  • Post-print
    • Author cannot archive a post-print version
  • Restrictions
    • 12 months embargo on science, technology, medicine articles
    • 2 years embargo on arts and humanities articles
    • Some titles may have different embargoes
  • Conditions
    • Pre-print can only be posted prior to acceptance
    • Pre-print must be accompanied by set statement (see link)
    • Pre-print must not be replaced with post-print, instead a link to published version with amended set statement should be made
    • Pre-print on author's personal website, employer website, free public server or pre-prints in subject area
    • Post-print in Institutional repositories or Central repositories
    • Publisher version cannot be used except for Nucleic Acids Research articles
    • Published source must be acknowledged
    • Must link to publisher version
    • Set phrase to accompany archived copy (see policy)
    • Articles in some journals can be made Open Access on payment of additional charge
    • Eligible UK authors may deposit in OpenDepot
    • Publisher will deposit on behalf of NIH funded authors to PubMed Central, Nucleic Acids Research authors must pay their fee first
    • Some titles may use different policies
  • Classification
    ​ yellow

Publications in this journal

  • Marta Biagioli, Francesco Ferrari, Eric M. Mendenhall, Yijing Zhang, Serkan Erdin, Ravi Vijayvargia, Sonia M. Vallabh, Nicole Solomos, Poornima Manavalan, Ashok Ragavendran, Fatih Ozsolak, Jong Min Lee, Michael E. Talkowski, James F. Gusella, Marcy E. MacDonald, Peter J. Park, Ihn Sik Seong
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    ABSTRACT: The CAG repeat expansion in the Huntington's disease gene HTT extends a polyglutamine tract in mutant huntingtin that enhances its ability to facilitate polycomb repressive complex 2 (PRC2). To gain insight into this dominant gain of function, we mapped histone modifications genome-wide across an isogenic panel of mouse embryonic stem cell (ESC) and neuronal progenitor cell (NPC) lines, comparing the effects of Htt null and different size Htt CAG mutations. We found that Htt is required in ESC for the proper deposition of histone H3K27me3 at a subset of ‘bivalent’ loci but in NPC is needed at ‘bivalent’ loci for both the proper maintenance and the appropriate removal of this mark. By contrast, Htt CAG size, though changing histone H3K27me3, is prominently associated with altered histone H3K4me3 at ‘active’ loci. The sets of ESC and NPC genes with altered histone marks delineated by the lack of huntingtin or the presence of mutant huntingtin, though distinct, are enriched in similar pathways with apoptosis specifically highlighted for the CAG mutation. Thus, the manner by which huntingtin function facilitates PRC2 may afford mutant huntingtin with multiple opportunities to impinge upon the broader machinery that orchestrates developmentally appropriate chromatin status.
    Human Molecular Genetics 01/2015;
  • Human Molecular Genetics 01/2015;
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    ABSTRACT: Toll-like receptor 4 (TLR4) recognizes specific structural motifs associated with microbial pathogens and also responds to certain endogenous host molecules associated with tissue damage. In Duchenne muscular dystrophy (DMD), inflammation plays an important role in determining the ultimate fate of dystrophic muscle fibers. In this study, we used TLR4-deficient dystrophic mdx mice to assess the role of TLR4 in the pathogenesis of DMD. TLR4 expression was increased and showed enhanced activation following agonist stimulation in mdx diaphragm muscle. Genetic ablation of TLR4 led to significantly increased muscle force generation in dystrophic diaphragm muscle, which was associated with improved histopathology including decreased fibrosis, as well as reduced pro-inflammatory gene expression and macrophage infiltration. TLR4 ablation in mdx mice also altered the phenotype of muscle macrophages by inducing a shift toward a more anti-inflammatory (iNOS(neg) CD206(pos)) profile. In vitro experiments confirmed that lack of TLR4 is sufficient to influence macrophage activation status in response to classical polarizing stimuli such as IFN-gamma and IL-4. Finally, treatment of dystrophic mice with glycyrrhizin, an inhibitor of the endogenous TLR4 ligand, high mobility group box (HMGB1), also pointed to involvement of the HMGB1-TLR4 axis in promoting dystrophic diaphragm pathology. Taken together, our findings reveal TLR4 and the innate immune system as important players in the pathophysiology of DMD. Accordingly, targeting either TLR4 or its endogenous ligands may provide a new therapeutic strategy to slow disease progression. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
    Human Molecular Genetics 12/2014;
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    ABSTRACT: Reduced activated partial thromboplastin time (aPTT) is a risk marker for incident and recurrent venous thromboembolism (VTE). Genetic factors influencing aPTT are not well understood, especially in populations of non-European ancestry. The present study aimed to identify aPTT-related gene variants in both European Americans (EAs) and African Americans (AAs). We conducted a genetic association study for aPTT in 9,719 EAs and 2,799 AAs from the Atherosclerosis Risk in Communities (ARIC) study. Using the Candidate Gene Association Resource (CARe) consortium candidate gene array, the analyses were based on approximately 50,000 SNPs in ∼2,000 candidate genes. In EAs, the analyses identified a new independent association for aPTT in F5 (rs2239852, p-value=1.9x10(-8)), which clusters with a coding variant rs6030 (p-value=7.8x10(-7)). The remaining significant signals were located on F5, HRG, KNG1, F11, F12, and ABO and have been previously reported in EA populations. In AAs, significant signals were identified in KNG1, HRG, F12, ABO, and VWF, with the leading variants in KNG1, HRG, and F12 being the same as in the EAs; the significant variant in VWF (rs2229446, p-value=1.2x10(-6)) was specific to the AA sample (minor allele frequency=19% in AAs and 0.2% in EAs) and has not been previously reported. This is the first study to report aPTT-related genetic variants in AAs. Our findings in AAs demonstrate transferability of previously reported associations with KNG1, HRG, and F12 in EAs. We also identified new associations at F5 in EAs and VWF in AAs that have not been previously reported for aPTT. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
    Human Molecular Genetics 12/2014;
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    ABSTRACT: Mutations in components of the molecular motor dynein/dynactin lead to neurodegenerative diseases of the motor system or atypical parkinsonism. These mutations are associated with prominent accumulation of vesicles involved in autophagy and lysosomal pathways, and with protein inclusions. Whether alleviating these defects would affect motor symptoms remain unknown. Here we show that a mouse model expressing low levels of disease linked-G59S mutant dynactin p150(Glued) develops motor dysfunction more than 8 months before loss of motor neurons or dopaminergic degeneration is observed. Abnormal accumulation of autophagosomes and protein inclusions were efficiently corrected by lowering dietary protein content, and this was associated with transcriptional upregulations of key players in autophagy. Most importantly this dietary modification partially rescued overall neurological symptoms in these mice after onset. Similar observations were made in another mouse strain carrying a point mutation in the dynein heavy chain gene. Collectively, our data suggest that stimulating the autophagy/lysosomal system through appropriate nutritional intervention has significant beneficial effects on motor symptoms of dynein/dynactin diseases even after symptom onset. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
    Human Molecular Genetics 12/2014;
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    ABSTRACT: Charcot-Marie-Tooth disease (CMT) is the most commonly inherited neurological disorder with a prevalence of 1 in 2,500 people worldwide. Patients suffer from degeneration of the peripheral nerves that control sensory information of the foot/leg and hand/arm. Multiple mutations in the neurofilament light polypeptide gene, NEFL, cause CMT2E. Previous studies in transfected cells showed that expression of disease-associated neurofilament light chain variants results in abnormal intermediate filament networks associated with defects in axonal transport. We have now generated knock-in mice with two different point mutations in Nefl: P8R that has been reported in multiple families with variable age of onset and N98S that has been described as an early onset, sporadic mutation in multiple individuals. Nefl(P8R/+) and Nefl(P8R/P8R) mice were indistinguishable from Nefl(+/+) in terms of behavioral phenotype. In contrast, Nefl(N98S/+) mice had a noticeable tremor and most animals showed a hind-limb clasping phenotype. Immunohistochemical analysis revealed multiple inclusions in the cell bodies and proximal axons of spinal cord neurons, disorganized processes in the cerebellum and abnormal processes in the cerebral cortex and pons. Abnormal processes were observed as early as post-natal day 7. Electron microscopic analysis of sciatic nerves showed a reduction in the number of neurofilaments, an increase in the number of microtubules and a decrease in the axonal diameters. The Nefl(N98S/+) mice provide an excellent model to study the pathogenesis of CMT2E and should prove useful for testing potential therapies. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
    Human Molecular Genetics 12/2014;
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    ABSTRACT: Accurate deleteriousness prediction for nonsynonymous variants is crucial for distinguishing pathogenic mutations from background polymorphisms in Whole Exome Sequencing studies. Although many deleteriousness prediction methods have been developed, their prediction results are sometimes inconsistent with each other and their relative merits are still unclear in practical applications. To address these issues, we comprehensively evaluated the predictive performance of eighteen current deleteriousness-scoring methods, including eleven function prediction scores (PolyPhen-2, SIFT, MutationTaster, Mutation Assessor, FATHMM, LRT, PANTHER, PhD-SNP, SNAP, SNPs&GO, and MutPred), three conservation scores (GERP++, SiPhy and PhyloP) and four ensemble scores (CADD, PON-P, KGGSeq and CONDEL). We found that FATHMM and KGGSeq had the highest discriminative power among independent scores and ensemble scores, respectively. Moreover, to ensure unbiased performance evaluation of these prediction scores, we manually collected three distinct testing datasets, on which no current prediction scores were tuned. In addition, we developed two new ensemble scores that integrate nine independent scores and allele frequency. Our scores achieved the highest discriminative power compared to all the deleteriousness prediction scores tested and showed low false positive prediction rate for benign yet rare nonsynonymous variants, which demonstrated the value of combining information from multiple orthologous approaches. Finally, to facilitate variant prioritization in Whole Exome Sequencing studies, we have pre-computed our ensemble scores for 87,347,044 possible variants in the whole-exome and made them publicly available through the ANNOVAR software and the dbNSFP database. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
    Human Molecular Genetics 12/2014;
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    ABSTRACT: Proper functioning of cilia, hair-like structures responsible for sensation and locomotion, requires nephrocystin-5 (NPHP5) and a multi-subunit complex called the Bardet-Biedl syndrome (BBS)ome, but their precise relationship is not understood. The BBSome is involved in the trafficking of membrane cargos to cilia. While it is known that a loss of any single subunit prevents ciliary trafficking of the BBSome and its cargos, the mechanisms underlying ciliary entry of this complex are not well characterized. Here, we report that a transition zone protein, NPHP5 contains two separate BBS-binding sites and interacts with the BBSome to mediate its integrity. Depletion of NPHP5, or expression of NPHP5 mutant missing one binding site, specifically leads to dissociation of BBS2 and BBS5 from the BBSome and loss of ciliary BBS2 and BBS5 without compromising the ability of the other subunits to traffic into cilia. Depletion of Cep290, another transition zone protein that directly binds to NPHP5, causes additional dissociation of BBS8 and loss of ciliary BBS8. Furthermore, delivery of BBSome cargos, smoothened, VPAC2 and Rab8a, to the ciliary compartment is completely disabled in the absence of single BBS subunits, but is selectively impaired in the absence of NPHP5 or Cep290. These findings define a new role of NPHP5 and Cep290 in controlling integrity and ciliary trafficking of the BBSome, which in turn impinge on the delivery of ciliary cargo. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
    Human Molecular Genetics 12/2014;
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    ABSTRACT: Mitochondrial diseases often exhibit tissue-specific pathologies, but this phenomenon is poorly understood. Here we present regulation of mitochondrial translation by the Mitochondrial Translation Optimization Factor 1, MTO1, as a novel player in this scenario. We demonstrate that MTO1 mediates tRNA modification and controls mitochondrial translation rate in a highly tissue specific manner associated with tissue-specific OXPHOS defects. Activation of mitochondrial proteases, aberrant translation products, as well as defects in OXPHOS complex assembly observed in MTO1 KO mice further imply that MTO1 impacts translation fidelity. In our mouse model, MTO1-related OXPHOS deficiency can be bypassed by feeding a ketogenic diet. This therapeutic intervention is independent of the MTO1-mediated tRNA modification and involves balancing of mitochondrial and cellular secondary stress responses. Our results thereby establish mammalian MTO1 as a novel factor in the tissue-specific regulation of OXPHOS and fine-tuning of mitochondrial translation accuracy. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
    Human Molecular Genetics 12/2014;
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    ABSTRACT: Maternal smoking during pregnancy has been found to influence newborn DNA methylation in genes involved in fundamental developmental processes. It is pertinent to understand the degree to which the offspring methylome is sensitive to the intensity and duration of prenatal smoking. An investigation of the persistence of offspring methylation associated with maternal smoking, and the relative roles of the intra-uterine and postnatal environment, is also warranted. In the Avon Longitudinal Study of Parents and Children, we investigated associations between prenatal exposure to maternal smoking and offspring DNA methylation at multiple time points in approximately 800 mother-offspring pairs. In cord blood, methylation at 15 CpG sites in seven gene regions (AHRR, MYO1G, GFI1, CYP1A1, CNTNAP2, KLF13 and ATP9A) was associated with maternal smoking and a dose-dependent response was observed in relation to smoking duration and intensity. Longitudinal analysis of blood DNA methylation in serial samples at birth, age 7 and age 17 years demonstrated that some CpG sites showed reversibility of methylation (GFI1, KLF13 and ATP9A) whereas others showed persistently perturbed patterns (AHRR, MYO1G, CYP1A1 and CNTNAP2). Of those showing persistence, we explored the effect of postnatal smoke exposure and found that the major contribution to altered methylation was attributed to a critical window of in-utero exposure. A comparison of paternal and maternal smoking and offspring methylation showed consistently stronger maternal associations, providing further evidence for causal intra-uterine mechanisms. These findings highlight the sensitivity of the methylome to maternal smoking during early development and the long-term impact of such exposure. © The Author 2014. Published by Oxford University Press.
    Human Molecular Genetics 12/2014;
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    ABSTRACT: Binding of cellular α-dystroglycan (α-DG) to its extracellular matrix ligands is fully dependent on a unique O-mannose-linked glycan. Disrupted O-mannosylation is the hallmark of the muscular dystrophy-dystroglycanopathy (MDDG) syndromes. SLC35A1, encoding the transporter of CMP-sialic acid, was recently identified as MDDG candidate gene. This is surprising, since sialic acid itself is dispensable for α-DG-ligand binding. In a novel SLC35A1-deficient cell model, we demonstrated a lack of α-DG O-mannosylation, ligand binding and incorporation of sialic acids. Removal of sialic acids from HAP1 wild type cells after incorporation or preventing sialylation during synthesis did not affect α-DG O-mannosylation or ligand binding but did affect sialylation. Lentiviral-mediated complementation with the only known disease mutation p.Q101H failed to restore deficient O-mannosylation in SLC35A1 knockout cells and partly restored sialylation. These data indicate a role for SLC35A1 in α-DG O-mannosylation that is distinct from sialic acid metabolism. In addition, human SLC35A1 deficiency can be considered as a combined disorder of α-DG O-mannosylation and sialylation, a novel variant of the MDDG syndromes. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
    Human Molecular Genetics 12/2014;
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    ABSTRACT: Abnormally phosphorylated Tau protein, the major component of neurofibrillary tangles, is critical in the pathogenesis of Alzheimer's disease and related Tauopathies. We used Drosophila to examine the role of key disease-associated phosphorylation sites on Tau-mediated neurotoxicity. We present evidence that the late-appearing phosphorylation on Ser(238) rather than hyper-phosphorylation per se is essential for Tau toxicity underlying premature mortality in adult flies. This site is also occupied at the time of neurodegeneration onset in a mouse Tauopathy model and in damaged brain areas of confirmed Tauopathy patients suggesting a similar critical role on Tau toxicity in humans. In contrast, occupation of Ser(262) is necessary for Tau-dependent learning deficits in adult Drosophila. Significantly, occupation of Ser(262) precedes and is required for Ser(238) phosphorylation and these temporally distinct phosphorylations likely reflect conformational changes. Because sequential occupation of Ser(262) and Ser(238) is required for the progression from Tau-mediated learning deficits to premature mortality in Drosophila, they may also play similar roles in the escalating symptom severity in Tauopathy patients, congruent with their presence in damaged regions of their brains. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
    Human Molecular Genetics 12/2014;
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    ABSTRACT: Nuclear lamins are involved in many cellular functions due to their ability to bind numerous partners including chromatin and transcription factors, and affect their properties. Dunnigan type familial partial lipodystrophy (FPLD2; OMIM#151660) is caused in most cases by the A-type lamin R482W mutation. We report here that the R482W mutation affects the regulatory activity of SREBP1, a transcription factor that regulates hundreds of genes involved in lipid metabolism and adipocyte differentiation. Using in situ proximity ligation assays, reporter assays and biochemical and transcriptomic approaches, we show that interactions of SREBP1 with lamin A (LMNA) and lamin C (LMNC) occur at the nuclear periphery and in the nucleoplasm. These interactions involve the Ig-fold of A-type lamins and are favored upon SREBP1 binding to its DNA target sequences. We show that SREBP1, LMNA and sterol response DNA elements form ternary complexes in vitro. In addition, overexpression of A-type lamins reduces transcriptional activity of SREBP1. In contrast, both overexpression of LMNA R482W in primary human preadipocytes and endogenous expression of A-type lamins R482W in FPLD2 patient fibroblasts, reduce A-type lamins-SREBP1 in situ interactions and upregulates a large number of SREBP1 target genes. As this LMNA mutant was previously shown to inhibit adipogenic differentiation, we propose that deregulation of SREBP1 by mutated A-type lamins constitutes one underlying mechanism of the physiopathology of FPLD2. Our data suggest that SREBP1 targeting molecules could be considered in a therapeutic context. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
    Human Molecular Genetics 12/2014;
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    ABSTRACT: Olfactomedin domain-containing proteins play roles in fundamental cellular processes, and have been implicated in disorders ranging from glaucoma, cancers, and inflammatory bowel disorder, to attention deficit disorder and childhood obesity. We solved crystal structures of the olfactomedin domain of myocilin (myoc-OLF), the best studied such domain to date. Mutations in myoc-OLF are causative in the autosomal dominant inherited form of the prevalent ocular disorder glaucoma. The structures reveal a new addition to the small family of five-bladed β-propellers. Propellers are most well known for their ability to act as hubs for protein-protein interactions, a function that seems most likely for myoc-OLF, but they can also act as enzymes. A calcium ion, sodium ion, and glycerol molecule were identified within a central hydrophilic cavity that is accessible via movements of surface loop residues. By mapping familial glaucoma-associated lesions onto the myoc-OLF structure, three regions sensitive to aggregation have been identified, with direct applicability to differentiating between neutral and disease-causing non-synonymous mutations documented in the human population worldwide. Evolutionary analysis mapped onto the myoc-OLF structure reveals conserved and divergent regions for possible overlapping and distinctive functional protein-protein or protein-ligand interactions across the broader OLF domain family. While deciphering the specific normal biological functions, ligands, and binding partners for olfactomedin domains will likely continue to be a challenging long-term experimental pursuit, atomic-detail structural knowledge of myoc-OLF is a valuable guide for understanding the implications of glaucoma-associated mutations and will help focus future studies of this biomedically important domain family. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
    Human Molecular Genetics 12/2014;
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    ABSTRACT: Gene therapy is an attractive tool for the treatment of monogenic disorders, in particular for lysosomal storage diseases (LSD) caused by deficiencies in secretable lysosomal enzymes in which neither full restoration of normal enzymatic activity nor transduction of all affected cells are necessary. However, some LSD such as Mucopolysaccharidosis Type IIIB (MPSIIIB) are challenging because the disease's main target organ is the brain and enzymes do not efficiently cross the blood-brain barrier even if present at very high concentration in circulation. To overcome these limitations, we delivered AAV9 vectors encoding for α-N-acetylglucosaminidase (NAGLU) to the Cerebrospinal Fluid (CSF) of MPSIIIB mice with the disease already detectable at biochemical, histological and functional level. Restoration of enzymatic activity in Central Nervous System (CNS) resulted in normalization of glycosaminoglycan content and lysosomal physiology, resolved neuroinflammation, and restored the pattern of gene expression in brain similar to that of healthy animals. Additionally, transduction of the liver due to passage of vectors to the circulation led to whole-body disease correction. Treated animals also showed reversal of behavioural deficits and extended lifespan. Importantly, when the levels of enzymatic activity were monitored in the CSF of dogs following administration of canine NAGLU-coding vectors to animals that were either naïve or had pre-existing immunity against AAV9, similar levels of activity were achieved, suggesting that CNS efficacy would not be compromised in patients seropositive for AAV9. Our studies provide a strong rationale for the clinical development of this novel therapeutic approach as treatment for MPSIIIB. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
    Human Molecular Genetics 12/2014;
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    ABSTRACT: Oligodendrocytes are coupled by gap junctions (GJs) formed mainly by connexin47 (Cx47) and Cx32. Recessive GJC2/Cx47 mutations cause Pelizeaus-Merzbacher-like disease (PMLD), a hypomyelinating leukodystrophy, while GJB1/Cx32 mutations cause neuropathy and chronic or acute-transient encephalopathy syndromes. Cx32/Cx47 double knockout (Cx32/Cx47dKO) mice develop severe CNS demyelination beginning at one month of age leading to death within weeks, offering a relevant model to study disease mechanisms. In order to clarify whether the loss of oligodendrocyte connexins has cell autonomous effects, we generated transgenic mice expressing the wild type (WT) human Cx32 under the control of the mouse proteolipid protein (Plp) promoter, obtaining exogenous hCx32 expression in oligodendrocytes. By crossing these mice with Cx32KO mice, we obtained expression of hCx32 on Cx32KO background. Immunohistochemical and immunoblot analysis confirmed strong CNS expression of hCx32 specifically in oligodendrocytes and correct localization forming GJs at cell bodies and along the myelin sheath. TG(+)Cx32/Cx47dKO mice generated by further crossing with Cx47KO mice showed that transgenic expression of hCx32 rescued the severe early phenotype of CNS demyelination in Cx32/Cx47dKO mice, resulting in marked improvement of behavioral abnormalities at one month of age, and preventing the early mortality. Furthermore, TG(+)Cx32/Cx47dKO mice showed significant improvement of myelination compared to Cx32/Cx47dKO CNS at one month of age, while the inflammatory and astrogliotic changes were fully reversed. Our study confirms that loss of oligodendrocyte GJs has cell autonomous effects and that re-establishment of GJ connectivity by replacement of least one GJ protein provides correction of the leukodystrophy phenotype. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
    Human Molecular Genetics 12/2014;
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    ABSTRACT: Duchenne muscular dystrophy (DMD) is caused by mutations in the dystrophin gene that result in loss of the dystrophin-glycoprotein complex, a laminin receptor that connects the myofiber to its surrounding extracellular matrix. Utrophin, a dystrophin ortholog that is normally localized to the neuromuscular junction, is naturally upregulated in DMD muscle, which partially compensates for the loss of dystrophin. Transgenic overexpression of utrophin causes broad sarcolemma localization of utrophin, restoration of laminin-binding, and amelioration of disease in the mdx mouse model of DMD. We previously demonstrated that overexpression of sarcospan, a dystrophin- and utrophin-binding protein, ameliorates mdx muscular dystrophy. Sarcospan boosts levels of utrophin to therapeutic levels at the sarcolemma, where attachment to laminin is restored. However, understanding the compensatory mechanism is complicated by concomitant upregulation of α7β1 integrin, which also binds laminin. Similar to the effects of utrophin, transgenic overexpression of α7 integrin prevents DMD disease in mice and is accompanied by increased abundance of utrophin around the extra-synaptic sarcolemma. In order to investigate the mechanisms underlying sarcospan 'rescue' of muscular dystrophy, we created double-knockout mice to test the contributions of utrophin or α7 integrin. We show that sarcospan-mediated amelioration of muscular dystrophy in DMD mice is dependent on the presence of both utrophin and α7β1 integrin, even when they are individually expressed at therapeutic levels. Furthermore, we found that association of sarcospan into laminin-binding complexes is dependent on utrophin and α7β1 integrin. Published by Oxford University Press 2014. This work is written by (a) US Government employee(s) and is in the public domain in the US.
    Human Molecular Genetics 12/2014;