Journal of Clinical Investigation (J CLIN INVEST)

Publications in this journal

• Article: SLITRK6 mutations cause myopia and deafness in humans and mice

  Tekin, M. Chioza, B. A. Matsumoto, Y. Diaz-Horta, O. Cross, H. E. Duman, D. Kokotas, H. Moore-Barton, H. L. Sakoori, K. Ota, [......], M. Petersen, M. B. Sreekantan-Nair, A. Gurtz, K. Xia, X. J. Pandya, A. Patton, M. A. Young, J. I. Aruga, J. Crosby, A. H
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  ABSTRACT: Myopia is by far the most common human eye disorder that is known to have a clear, albeit poorly defined, heritable component. In this study, we describe an autosomal-recessive syndrome characterized by high myopia and sensorineural deafness. Our molecular investigation in 3 families led to the identification of 3 homozygous nonsense mutations (p.R181X, p.S297X, and p.Q414X) in SLIT and NTRK-like family, member 6 (SLITRK6), a leucine-rich repeat domain transmembrane protein. All 3 mutant SLITRK6 proteins displayed defective cell surface localization. High-resolution MRI of WT and Slitrk6-deficient mouse eyes revealed axial length increase in the mutant (the endophenotype of myopia). Additionally, mutant mice exhibited auditory function deficits that mirrored the human phenotype. Histological investigation of WT and Slitrk6-deficient mouse retinas in postnatal development indicated a delay in synaptogenesis in Slitrk6-deficient animals. Taken together, our results showed that SLITRK6 plays a crucial role in the development of normal hearing as well as vision in humans and in mice and that its disruption leads to a syndrome characterized by severe myopia and deafness.
  Journal of Clinical Investigation 04/2013;
• Article: Desmoglein-1, differentiation, and disease

  Christoph M. Hammers, John R. Stanley
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  ABSTRACT: Desmoglein-1 (DSG1), a desmosomal protein, maintains the structure of epidermis through its adhesive function. However, heterozygous mutations in DSG1 in humans result in abnormal differentiation, as does downregulation of DSG1 in human skin organ culture, suggesting that it may have important signaling functions. In this issue of the JCI, Harmon et al. elucidate how the binding of the DSG1 cytoplasmic tail to the scaffolding protein Erbin decreases signaling through the Ras-Raf pathway to promote stratification and differentiation of keratinocytes in the epidermis.
  Journal of Clinical Investigation 03/2013;
• Article: iRHOM2 is a critical pathogenic mediator of inflammatory arthritis.

  Issuree PD, Maretzky T, McIlwain DR, Monette S, Qing X, Lang PA, Swendeman SL, Park-Min KH, Binder N, Kalliolias GD, Yarilina A, Horiuchi K, Ivashkiv LB, Mak TW, Salmon JE, Blobel CP
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  ABSTRACT: iRHOM2, encoded by the gene Rhbdf2, regulates the maturation of the TNF-α convertase (TACE), which controls shedding of TNF-α and its biological activity in vivo. TACE is a potential target to treat TNF-α-dependent diseases, such as rheumatoid arthritis, but there are concerns about potential side effects, because TACE also protects the skin and intestinal barrier by activating EGFR signaling. Here we report that inactivation of Rhbdf2 allows tissue-specific regulation of TACE by selectively preventing its maturation in immune cells, without affecting its homeostatic functions in other tissues. The related iRHOM1, which is widely expressed, except in hematopoietic cells, supported TACE maturation and shedding of the EGFR ligand TGF-α in Rhbdf2-deficient cells. Remarkably, mice lacking Rhbdf2 were protected from K/BxN inflammatory arthritis to the same extent as mice lacking TACE in myeloid cells or Tnfa-deficient mice. In probing the underlying mechanism, we found that two main drivers of K/BxN arthritis, complement C5a and immune complexes, stimulated iRHOM2/TACE-dependent shedding of TNF-α in mouse and human cells. These data demonstrate that iRHOM2 and myeloid-expressed TACE play a critical role in inflammatory arthritis and indicate that iRHOM2 is a potential therapeutic target for selective inactivation of TACE in myeloid cells.
  Journal of Clinical Investigation 01/2013;
• Article: The LINC complex is essential for hearing

  Henning F. Horn, Zippora Brownstein, Danielle R. Lenz, Shaked Shivatzki, Amiel A. Dror, Orit Dagan-Rosenfeld, Lilach M. Friedman, Kyle J. Roux, Serguei Kozlov, Kuan-Teh Jeang, Moshe Frydman, Brian Burke, Colin L. Stewart, Karen B. Avraham
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  ABSTRACT: Hereditary hearing loss is the most common sensory deficit. We determined that progressive high-frequency hearing loss in 2 families of Iraqi Jewish ancestry was due to homozygosity for the protein truncating mutation SYNE4 c.228delAT. SYNE4, a gene not previously associated with hearing loss, encodes nesprin-4 (NESP4), an outer nuclear membrane (ONM) protein expressed in the hair cells of the inner ear. The truncated NESP4 encoded by the families’ mutation did not localize to the ONM. NESP4 and SUN domain–containing protein 1 (SUN1), which localizes to the inner nuclear membrane (INM), are part of the linker of nucleoskeleton and cytoskeleton (LINC) complex in the nuclear envelope. Mice lacking either Nesp4 or Sun1 were evaluated for hair cell defects and hearing loss. In both Nesp4–/– and Sun1–/– mice, OHCs formed normally, but degenerated as hearing matured, leading to progressive hearing loss. The nuclei of OHCs from mutant mice failed to maintain their basal localization, potentially affecting cell motility and hence the response to sound. These results demonstrate that the LINC complex is essential for viability and normal morphology of OHCs and suggest that the position of the nucleus in sensory epithelial cells is critical for maintenance of normal hearing.
  Journal of Clinical Investigation 01/2013; 123(2):740.
• Article: 8-Oxoguanine causes neurodegeneration during MUTYH-mediated DNA base excision repair

  Sheng, Z. Oka, S. Tsuchimoto, D. Abolhassani, N. Nomaru, H. Sakumi, K. Yamada, H. Nakabeppu
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  ABSTRACT: 8-Oxoguanine (8-oxoG), a common DNA lesion caused by reactive oxygen species, is associated with carcinogenesis and neurodegeneration. Although the mechanism by which 8-oxoG causes carcinogenesis is well understood, the mechanism by which it causes neurodegeneration is unknown. Here, we report that neurodegeneration is triggered by MUTYH-mediated excision repair of 8-oxoG-paired adenine. Mutant mice lacking 8-oxo-2'-deoxyguanosine triphosphate-depleting (8-oxo-dGTP-depleting) MTH1 and/or 8-oxoG-excising OGG1 exhibited severe striatal neurodegeneration, whereas mutant mice lacking MUTYH or OGG1/MUTYH were resistant to neurodegeneration under conditions of oxidative stress. These results indicate that OGG1 and MTH1 are protective, while MUTYH promotes neurodegeneration. We observed that 8-oxoG accumulated in the mitochondrial DNA of neurons and caused calpain-dependent neuronal loss, while delayed nuclear accumulation of 8-oxoG in microglia resulted in PARP-dependent activation of apoptosis-inducing factor and exacerbated microgliosis. These results revealed that neurodegeneration is a complex process caused by 8-oxoG accumulation in the genomes of neurons and microglia. Different signaling pathways were triggered by the accumulation of single-strand breaks in each type of DNA generated during base excision repair initiated by MUTYH, suggesting that suppression of MUTYH may protect the brain under conditions of oxidative stress.
  Journal of Clinical Investigation 12/2012; 122(12):4344-4361.
• Article: Attenuated adenosine-to-inosine editing of microRNA-376a* promotes invasiveness of glioblastoma cells

  Choudhury Y, Tay FC, Lam DH, Sandanaraj E, Tang C, Ang BT, Wang S
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  ABSTRACT: In the human brain, microRNAs (miRNAs) from the microRNA-376 (miR-376) cluster undergo programmed "seed" sequence modifications by adenosine-to-inosine (A-to-I) editing. Emerging evidence suggests a link between impaired A-to-I editing and cancer, particularly in high-grade gliomas. We hypothesized that disruption of A-to-I editing alters expression of genes regulating glioma tumor phenotypes. By sequencing the miR-376 cluster, we show that the overall miRNA editing frequencies were reduced in human gliomas. Specifically in high-grade gliomas, miR-376a* accumulated entirely in an unedited form. Clinically, a significant correlation was found between accumulation of unedited miR-376a* and the extent of invasive tumor spread as measured by magnetic resonance imaging of patient brains. Using both in vitro and orthotopic xenograft mouse models, we demonstrated that the unedited miR-376a* promoted glioma cell migration and invasion, while the edited miR-376a* suppressed these features. The effects of the unedited miR-376a* were mediated by its sequence-dependent ability to target RAP2A and concomitant inability to target AMFR. Thus, the tumor-dependent introduction of a single base difference in the miR-376a* sequence dramatically alters the selection of its target genes and redirects its function from inhibiting to promoting glioma cell invasion. These findings uncover a new mechanism of miRNA deregulation and identify unedited miR-376a* as a potential therapeutic target in glioblastoma cells
  Journal of Clinical Investigation 10/2012; 122(11).
• Article: Comparing human pancreatic cell secretomes by in vitro aptamer selection identifies cyclophilin B as a candidate pancreatic cancer biomarker.

  Ray P, Rialon-Guevara KL, Veras E, Sullenger BA, White RR
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  ABSTRACT: Most cases of pancreatic cancer are not diagnosed until they are no longer curable with surgery. Therefore, it is critical to develop a sensitive, preferably noninvasive, method for detecting the disease at an earlier stage. In order to identify biomarkers for pancreatic cancer, we devised an in vitro positive/negative selection strategy to identify RNA ligands (aptamers) that could detect structural differences between the secretomes of pancreatic cancer and non-cancerous cells. Using this molecular recognition approach, we identified an aptamer (M9-5) that differentially bound conditioned media from cancerous and non-cancerous human pancreatic cell lines. This aptamer further discriminated between the sera of pancreatic cancer patients and healthy volunteers with high sensitivity and specificity. We utilized biochemical purification methods and mass-spectrometric analysis to identify the M9-5 target as cyclophilin B (CypB). This molecular recognition-based strategy simultaneously identified CypB as a serum biomarker and generated a new reagent to recognize it in body fluids. Moreover, this approach should be generalizable to other diseases and complementary to traditional approaches that focus on differences in expression level between samples. Finally, we suggest that the aptamer we identified has the potential to serve as a tool for the early detection of pancreatic cancer.
  Journal of Clinical Investigation 04/2012;
• Article: Recurrent genomic instability of chromosome 1q in neural derivatives of human embryonic stem cells

  Varela C, Denis J, Polentes J, Feyeux M, Aubert S, Champon B, Piétu G, Peschanski M, Lefort N
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  ABSTRACT: Human pluripotent stem cells offer a limitless source of cells for regenerative medicine. Neural derivatives of human embryonic stem cells (hESCs) are currently being used for cell therapy in 3 clinical trials. However, hESCs are prone to genomic instability, which could limit their clinical utility. Here, we report that neural differentiation of hESCs systematically produced a neural stem cell population that could be propagated for more than 50 passages without entering senescence; this was true for all 6 hESC lines tested. The apparent spontaneous loss of evolution toward normal senescence of somatic cells was associated with a jumping translocation of chromosome 1q. This chromosomal defect has previously been associated with hematologic malignancies and pediatric brain tumors with poor clinical outcome. Neural stem cells carrying the 1q defect implanted into the brains of rats failed to integrate and expand, whereas normal cells engrafted. Our results call for additional quality controls to be implemented to ensure genomic integrity not only of undifferentiated pluripotent stem cells, but also of hESC derivatives that form cell therapy end products, particularly neural lines
  Journal of Clinical Investigation 02/2012;
• Article: Recurrent genomic instability of chromosome 1q in neural derivatives of human embryonic stem cells.

  Recurrent genomic instability of chromosome 1q in neural derivatives of human embryonic stem cells
  [show abstract] [hide abstract]
  ABSTRACT: Human pluripotent stem cells offer a limitless source of cells for regenerative medicine. Neural derivatives of human embryonic stem cells (hESCs) are currently being used for cell therapy in 3 clinical trials. However, hESCs are prone to genomic instability, which could limit their clinical utility. Here, we report that neural differentiation of hESCs systematically produced a neural stem cell population that could be propagated for more than 50 passages without entering senescence; this was true for all 6 hESC lines tested. The apparent spontaneous loss of evolution toward normal senescence of somatic cells was associated with a jumping translocation of chromosome 1q. This chromosomal defect has previously been associated with hematologic malignancies and pediatric brain tumors with poor clinical outcome. Neural stem cells carrying the 1q defect implanted into the brains of rats failed to integrate and expand, whereas normal cells engrafted. Our results call for additional quality controls to be implemented to ensure genomic integrity not only of undifferentiated pluripotent stem cells, but also of hESC derivatives that form cell therapy end products, particularly neural lines.
  Journal of Clinical Investigation 02/2012;
• Article: GATA believe it: new essential regulators of pancreas development

  Rodríguez-Seguí S, Akerman I, Ferrer J
  Journal of Clinical Investigation 01/2012;
• Article: Brown adipose tissue oxidative metabolism contributes to energy expenditure during acute cold exposure in humans

  Véronique Ouellet, Sébastien M. Labbé, Denis P. Blondin, Serge Phoenix, Brigitte Guérin, François Haman, Eric E. Turcotte, Denis Richard, André C. Carpentier
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  ABSTRACT: Recent studies using PET with 18F-fluorodeoxyglucose (18FDG) have shown the presence of brown adipose tissue (BAT). Whether BAT contributes to cold-induced non-shivering thermogenesis has however not been proven in adult humans. Using PET with 11C-acetate, 18FDG and 18F-fluoro-thiaheptadecanoic acid (18FTHA, a fatty acid tracer), BAT oxidative metabolism, glucose and nonesterified fatty acid (NEFA) turnover were quantified in six healthy men under controlled cold exposure condition designed to minimize shivering. Upon cold exposure, we showed significant NEFA uptake in addition to glucose uptake. We demonstrated significant cold-induced activation of oxidative metabolism in BAT, but not in adjoining skeletal muscles and subcutaneous adipose tissue. This was associated with a 1.8-fold increase in total energy expenditure. We found a significant inverse relationship between BAT volume of activity and shivering and significant increase in BAT radio-density, indicating reduced BAT triglyceride content. The present study demonstrates that BAT represents a non-shivering thermogenesis effector in humans.
  Journal of Clinical Investigation 01/2012;
• Article: Adipose tissue remodeling and obesity.

  Sun K, Kusminski CM, Scherer PE
  Journal of Clinical Investigation 06/2011;