Authors: Monzack EL, May LA, Roy S, Gale JE, Cunningham LL
Journal: Cell Death Differ. 2015 May 1. doi: 10.1038/cdd.2015.48.
Hearing loss and balance disorders affect millions of people worldwide. Sensory transduction in the inner ear requires both mechanosensory hair cells (HCs) and surrounding glia-like supporting cells (SCs). HCs are susceptible to death from aging, noise overexposure, and treatment with therapeutic drugs that have ototoxic side effects; these ototoxic drugs include the aminoglycoside antibiotics and the antineoplastic drug cisplatin. Although both classes of drugs are known to kill HCs, their effects on SCs are less well understood. Recent data indicate that SCs sense and respond to HC stress, and that their responses can influence HC death, survival, and phagocytosis. These responses to HC stress and death are critical to the health of the inner ear. Here we have used live confocal imaging of the adult mouse utricle, to examine the SC responses to HC death caused by aminoglycosides or cisplatin. Our data indicate that when HCs are killed by aminoglycosides, SCs efficiently remove HC corpses from the sensory epithelium in a process that includes constricting the apical portion of the HC after loss of membrane integrity. SCs then form a phagosome, which can completely engulf the remaining HC body, a phenomenon not previously reported in mammals. In contrast, cisplatin treatment results in accumulation of dead HCs in the sensory epithelium, accompanied by an increase in SC death. The surviving SCs constrict fewer HCs and display impaired phagocytosis. These data are supported by in vivo experiments, in which cochlear SCs show reduced capacity for scar formation in cisplatin-treated mice compared with those treated with aminoglycosides. Together, these data point to a broader defect in the ability of the cisplatin-treated SCs, to preserve tissue health in the mature mammalian inner ear.
Authors: Mueller GA, Pedersen LC, Glesner J, Edwards LL, Zakzuk J, London RE, Arruda LK, Chapman MD, Caraballo L, Pomés A.
Journal: J Allergy Clin Immunol. 2015 Apr 27. pii: S0091-6749(15)00414-5. doi: 10.1016/j.jaci.2015.03.015. [Epub ahead of print]
BACKGROUND: It is not clear whether cross-reactivity or cosensitization to glutathione S-transferases (GSTs) occurs in tropical and subtropical environments. In the United States, Bla g 5 is the most important GST allergen and lack of coexposure to GSTs from certain species allows a better assessment of cross-reactivity.
OBJECTIVES: To examine the molecular structure of GST allergens from cockroach (Bla g 5), dust mites (Der p 8 and Blo t 8), and helminth (Asc s 13) for potential cross-reactive sites, and to assess the IgE cross-reactivity of sensitized patients from a temperate climate for these allergens for molecular diagnostic purposes.
METHODS: Four crystal structures were determined. Sera from patients allergic to cockroach and mite were tested for IgE reactivity to these GSTs. A panel of 6 murine anti-Bla g 5 mAb was assessed for cross-reactivity with the other 3 GSTs using antibody binding assays.
RESULTS: Comparisons of the allergen structures, formed by 2-domain monomers that dimerize, revealed few contiguous regions of similar exposed residues, rendering cross-reactivity unlikely. Accordingly, anti-Bla g 5 or anti-Der p 8 IgE from North American patients did not recognize Der p 8 or Bla g 5, respectively, and neither showed binding to Blo t 8 or Asc s 13. A weaker binding of anti-Bla g 5 IgE to Der p 8 versus Bla g 5 (∼100-fold) was observed by inhibition assays, similar to a weak recognition of Der p 8 by anti-Bla g 5 mAb. Patients from tropical Colombia had IgE to all 4 GSTs.
CONCLUSIONS: The lack of significant IgE cross-reactivity among the 4 GSTs is in agreement with the low shared amino acid identity at the molecular surface. Each GST is needed for accurate molecular diagnosis in different geographic areas.
Authors: Liu C, Peng J, Matzuk MM, Yao HH
Journal: Nat Commun. 2015 Apr 28;6:6934. doi: 10.1038/ncomms7934
Organogenesis of the ovary is a highly orchestrated process involving multiple lineage determination of ovarian surface epithelium, granulosa cells and theca cells. Although the sources of ovarian surface epithelium and granulosa cells are known, the origin(s) of theca progenitor cells have not been definitively identified. Here we show that theca cells derive from two sources: Wt1(+) cells indigenous to the ovary and Gli1(+) mesenchymal cells that migrate from the mesonephros. These progenitors acquire theca lineage marker Gli1 in response to paracrine signals Desert hedgehog (Dhh) and Indian hedgehog (Ihh) from granulosa cells. Ovaries lacking Dhh/Ihh exhibit theca layer loss, blunted steroid production, arrested folliculogenesis and failure to form corpora lutea. Production of Dhh/Ihh in granulosa cells requires growth differentiation factor 9 (GDF9) from the oocyte. Our studies provide the first genetic evidence for the origins of theca cells and reveal a multicellular interaction critical for the formation of a functional theca.
Authors: Hanaoka H, Nakajima T, Sato K, Watanabe R, Phung Y, Gao W, Harada T, Kim I, Paik CH, Choyke PL, Ho M, Kobayashi H
Journal: Nanomedicine (Lond). 2015 Apr;10(7):1139-47. doi: 10.2217/nnm.14.194
AIM: Effectiveness of Glypican-3 (GPC3)-targeted photoimmunotherapy (PIT) combined with the nanoparticle albumin-bound paclitaxel (nab-paclitaxel) for hepatocellular carcinoma was evaluated.
MATERIALS & METHODS: GPC3 expressing A431/G1 cells were incubated with a phthalocyanine-derivative, IRDye700DX (IR700), conjugated to an anti-GPC3 antibody, IR700-YP7 and exposed to near-infrared light. Therapeutic experiments combining GPC3-targeted PIT with nab-paclitaxel were performed in A431/G1 tumor-bearing mice.
RESULTS: IR700-YP7 bound to A431/G1 cells and induced rapid target-specific necrotic cell death by near-infrared light exposure in vitro. IR700-YP7 accumulated in A431/G1 tumors. Tumor growth was inhibited by PIT compared with nontreated control. Additionally, PIT dramatically increased nab-paclitaxel delivery and enhanced the therapeutic effect.
CONCLUSION: PIT targeting GPC3 combined with nab-paclitaxel is a promising method for treating hepatocellular carcinoma.
Authors: Machiela MJ, Zhou W, Sampson JN, Dean MC, Jacobs KB, Black A, Brinton LA, Chang IS, Chen C, Chen C, Chen K, Cook LS, Crous Bou M, De Vivo I, Doherty J, Friedenreich CM, Gaudet MM, Haiman CA, Hankinson SE, Hartge P, Henderson BE, Hong YC, Hosgood HD 3rd, Hsiung CA, Hu W, Hunter DJ, Jessop L, Kim HN, Kim YH, Kim YT, Klein R, Kraft P, Lan Q, Lin D, Liu J, Le Marchand L, Liang X, Lissowska J, Lu L, Magliocco AM, Matsuo K, Olson SH, Orlow I, Park JY, Pooler L, Prescott J, Rastogi R, Risch HA, Schumacher F, Seow A, Setiawan VW, Shen H, Sheng X, Shin MH, Shu XO, VanDen Berg D, Wang JC, Wentzensen N, Wong MP, Wu C, Wu T, Wu YL, Xia L, Yang HP, Yang PC, Zheng W, Zhou B, Abnet CC, Albanes D, Aldrich MC, Amos C, Amundadottir LT, Berndt SI, Blot WJ, Bock CH, Bracci PM, Burdett L, Buring JE, Butler MA, Carreón T, Chatterjee N, Chung CC, Cook MB, Cullen M, Davis FG, Ding T, Duell EJ, Epstein CG, Fan JH, Figueroa JD, Fraumeni JF Jr, Freedman ND, Fuchs CS, Gao YT, Gapstur SM, Patiño-Garcia A, Garcia-Closas M, Gaziano JM, Giles GG, Gillanders EM, Giovannucci EL, Goldin L, Goldstein AM, Greene MH, Hallmans G, Harris CC, Henriksson R, Holly EA, Hoover RN, Hu N, Hutchinson A, Jenab M, Johansen C, Khaw KT, Koh WP, Kolonel LN, Kooperberg C, Krogh V, Kurtz RC, LaCroix A, Landgren A, Landi MT, Li D, Liao LM, Malats N, McGlynn KA, McNeill LH, McWilliams RR, Melin BS, Mirabello L, Peplonska B, Peters U, Petersen GM, Prokunina-Olsson L, Purdue M, Qiao YL, Rabe KG, Rajaraman P, Real FX, Riboli E, Rodríguez-Santiago B, Rothman N, Ruder AM, Savage SA, Schwartz AG, Schwartz KL, Sesso HD, Severi G, Silverman DT, Spitz MR, Stevens VL, Stolzenberg-Solomon R, Stram D, Tang ZZ, Taylor PR, Teras LR, Tobias GS, Viswanathan K, Wacholder S, Wang Z, Weinstein SJ, Wheeler W, White E, Wiencke JK, Wolpin BM, Wu X, Wunder JS, Yu K, Zanetti KA, Zeleniuch-Jacquotte A, Ziegler RG, de Andrade M, Barnes KC, Beaty TH, Bierut LJ, Desch KC, Doheny KF, Feenstra B, Ginsburg D, Heit JA, Kang JH, Laurie CA, Li JZ, Lowe WL, Marazita ML, Melbye M, Mirel DB, Murray JC, Nelson SC, Pasquale LR, Rice K, Wiggs JL, Wise A, Tucker M, Pérez-Jurado LA, Laurie CC, Caporaso NE, Yeager M, Chanock SJ
Journal: Am J Hum Genet. 2015 Mar 5;96(3):487-97. doi: 10.1016/j.ajhg.2015.01.011
Analyses of genome-wide association study (GWAS) data have revealed that detectable genetic mosaicism involving large (>2 Mb) structural autosomal alterations occurs in a fraction of individuals. We present results for a set of 24,849 genotyped individuals (total GWAS set II [TGSII]) in whom 341 large autosomal abnormalities were observed in 168 (0.68%) individuals. Merging data from the new TGSII set with data from two prior reports (the Gene-Environment Association Studies and the total GWAS set I) generated a large dataset of 127,179 individuals; we then conducted a meta-analysis to investigate the patterns of detectable autosomal mosaicism (n = 1,315 events in 925 [0.73%] individuals). Restricting to events >2 Mb in size, we observed an increase in event frequency as event size decreased. The combined results underscore that the rate of detectable mosaicism increases with age (p value = 5.5 × 10(-31)) and is higher in men (p value = 0.002) but lower in participants of African ancestry (p value = 0.003). In a subset of 47 individuals from whom serial samples were collected up to 6 years apart, complex changes were noted over time and showed an overall increase in the proportion of mosaic cells as age increased. Our large combined sample allowed for a unique ability to characterize detectable genetic mosaicism involving large structural events and strengthens the emerging evidence of non-random erosion of the genome in the aging population.
Authors: Williams JS, Clausen AR, Lujan SA, Marjavaara L, Clark AB, Burgers PM, Chabes A, Kunkel TA
Journal: Nat Struct Mol Biol. 2015 Mar 9. doi: 10.1038/nsmb.2989. [Epub ahead of print]
Ribonucleotides incorporated during DNA replication are removed by RNase H2-dependent ribonucleotide excision repair (RER). In RER-defective yeast, topoisomerase 1 (Top1) incises DNA at unrepaired ribonucleotides, initiating their removal, but this is accompanied by RNA-DNA-damage phenotypes. Here we show that these phenotypes are incurred by a high level of ribonucleotides incorporated by a leading strand-replicase variant, DNA polymerase (Pol) ɛ, but not by orthologous variants of the lagging-strand replicases, Pols α or δ. Moreover, loss of both RNases H1 and H2 is lethal in combination with increased ribonucleotide incorporation by Pol ɛ but not by Pols α or δ. Several explanations for this asymmetry are considered, including the idea that Top1 incision at ribonucleotides relieves torsional stress in the nascent leading strand but not in the nascent lagging strand, in which preexisting nicks prevent the accumulation of superhelical tension.
Authors: Williams LH, Fromm G, Gokey NG, Henriques T, Muse GW, Burkholder A, Fargo DC, Hu G, Adelman K
Journal: Mol Cell. 2015 Mar 11. pii: S1097-2765(15)00095-7. doi: 10.1016/j.molcel.2015.02.003. [Epub ahead of print]
The remarkable capacity for pluripotency and self-renewal in embryonic stem cells (ESCs) requires a finely tuned transcriptional circuitry wherein the pathways and genes that initiate differentiation are suppressed, but poised to respond rapidly to developmental signals. To elucidate transcriptional control in mouse ESCs in the naive, ground state, we defined the distribution of engaged RNA polymerase II (Pol II) at high resolution. We find that promoter-proximal pausing of Pol II is most enriched at genes regulating cell cycle and signal transduction and not, as expected, at developmental or bivalent genes. Accordingly, ablation of the primary pause-inducing factor NELF does not increase expression of lineage markers, but instead causes proliferation defects, embryonic lethality, and dysregulation of ESC signaling pathways. Indeed, ESCs lacking NELF have dramatically attenuated FGF/ERK activity, rendering them resistant to differentiation. This work thus uncovers a key role for NELF-mediated pausing in establishing the responsiveness of stem cells to developmental cues.
Authors: Zhang D, Gao ZG, Zhang K, Kiselev E, Crane S, Wang J, Paoletta S, Yi C, Ma L, Zhang W, Han GW, Liu H, Cherezov V, Katritch V4, Jiang H5, Stevens RC6, Jacobson KA2, Zhao Q1, Wu B1.
Journal: Nature. 2015 Mar 30. doi: 10.1038/nature14287. [Epub ahead of print]
In response to adenosine 5'-diphosphate, the P2Y1 receptor (P2Y1R) facilitates platelet aggregation, and thus serves as an important antithrombotic drug target. Here we report the crystal structures of the human P2Y1R in complex with a nucleotide antagonist MRS2500 at 2.7 Å resolution, and with a non-nucleotide antagonist BPTU at 2.2 Å resolution. The structures reveal two distinct ligand-binding sites, providing atomic details of P2Y1R's unique ligand-binding modes. MRS2500 recognizes a binding site within the seven transmembrane bundle of P2Y1R, which is different in shape and location from the nucleotide binding site in the previously determined structure of P2Y12R, representative of another P2YR subfamily. BPTU binds to an allosteric pocket on the external receptor interface with the lipid bilayer, making it the first structurally characterized selective G-protein-coupled receptor (GPCR) ligand located entirely outside of the helical bundle. These high-resolution insights into P2Y1R should enable discovery of new orthosteric and allosteric antithrombotic drugs with reduced adverse effects.
Authors: Gadalla SM, Wang T, Haagenson M, Spellman SR, Lee SJ, Williams KM, Wong JY, De Vivo I, Savage SA
Journal: JAMA. 2015 Feb 10;313(6):594-602. doi: 10.1001/jama.2015.7
IMPORTANCE: Telomeres protect chromosome ends and are markers of cellular aging and replicative capacity.
OBJECTIVE: To evaluate the association between recipient and donor pretransplant leukocyte telomere length with outcomes after unrelated donor allogeneic hematopoietic cell transplantation (HCT) for patients with severe aplastic anemia.
DESIGN, PARTICIPANTS, AND SETTING: The study included 330 patients (235 acquired, 85 Fanconi anemia, and 10 Diamond-Blackfan anemia) and their unrelated donors who had pre-HCT blood samples and clinical and outcome data available at the Center for International Blood and Marrow Transplant Research. Patients underwent HCT between 1989 and 2007 in 84 centers and were followed-up to March 2013.
EXPOSURES: Recipient and donor pre-HCT leukocyte telomere length classified into long (third tertile) and short (first and second tertiles combined) based on donor telomere length distribution.
MAIN OUTCOMES AND MEASURES: Overall survival, neutrophil recovery, and acute and chronic graft-vs-host disease, as ascertained by transplant centers through regular patient follow-up.
RESULTS: Longer donor leukocyte telomere length was associated with higher survival probability (5-year overall survival, 56%; number at risk, 57; cumulative deaths, 50) than shorter donor leukocyte telomere length (5-year overall survival, 40%; number at risk, 71; cumulative deaths, 128; P = .009). The association remained statistically significant after adjusting for donor age, disease subtype, Karnofsky performance score, graft type, HLA matching, prior aplastic anemia therapy, race/ethnicity, and calendar year of transplant (hazard ratio [HR], 0.61; 95% CI, 0.44-0.86). Similar results were noted in analyses stratified on severe aplastic anemia subtype, recipient age, HLA matching, calendar year of transplant, and conditioning regimen. There was no association between donor telomere length and neutrophil engraftment at 28 days (cumulative incidence, 86% vs 85%; HR, 0.94; 95% CI, 0.73-1.22), acute graft-vs-host disease grades III-IV at 100 days (cumulative incidence, 22% vs 28%; HR, 0.77; 95% CI, 0.48-1.23), or chronic graft-vs-host disease at 1-year (cumulative incidence, 28% vs 30%; HR, 0.81; 95% CI, 0.53-1.24) for long vs short, respectively. Pretransplant leukocyte telomere length in the recipients was not associated with posttransplant survival (HR, 0.91; 95% CI, 0.64-1.30).
CONCLUSIONS AND RELEVANCE: Longer donor leukocyte telomere length was associated with increased 5-year survival in patients who received HCT for severe aplastic anemia. Patient leukocyte telomere length was not associated with survival. The results of this observational study suggest that donor leukocyte telomere length may have a role in long-term posttransplant survival.
Authors: Robbins HA, Pfeiffer RM, Shiels MS, Li J, Hall HI, Engels EA
Journal: J Natl Cancer Inst. 2015 Feb 6;107(4). pii: dju503. doi: 10.1093/jnci/dju503. Print 2015 Apr.
BACKGROUND: Nearly 900 000 people in the United States are living with diagnosed human immunodeficiency virus (HIV) infection and therefore increased cancer risk. The total number of cancers occurring among HIV-infected people and the excess number above expected background cases are unknown.
METHODS: We derived cancer incidence rates for the United States HIV-infected and general populations from Poisson models applied to linked HIV and cancer registry data and from Surveillance, Epidemiology, and End Results program data, respectively. We applied these rates to estimates of people living with diagnosed HIV at mid-year 2010 to estimate total and expected cancer counts, respectively. We subtracted expected from total cancers to estimate excess cancers.
RESULTS: An estimated 7760 (95% confidence interval [CI] = 7330 to 8320) cancers occurred in 2010 among HIV-infected people, of which 3920 cancers (95% CI = 3480 to 4470) or 50% (95% CI = 48 to 54%) were in excess of expected. The most common excess cancers were non-Hodgkin's lymphoma (NHL; n = 1440 excess cancers, occurring in 88% excess), Kaposi's sarcoma (KS, n = 910, 100% excess), anal cancer (n = 740, 97% excess), and lung cancer (n = 440, 52% excess). The proportion of excess cancers that were AIDS defining (ie, KS, NHL, cervical cancer) declined with age and time since AIDS diagnosis (both P < .001). For anal cancer, 83% of excess cases occurred among men who have sex with men, and 71% among those living five or more years since AIDS onset. Among injection drug users, 22% of excess cancers were lung cancer, and 16% were liver cancer.
CONCLUSIONS: The excess cancer burden in the US HIV population is substantial, and patterns across groups highlight opportunities for cancer control initiatives targeted to HIV-infected people.