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3. Biophysics of microRNA-34a targeting and its influence on down-regulation

Author

Sweetapple, Lara, primary, Kosek, David M, additional, Banijamali, Elnaz, additional, Becker, Walter, additional, Müller, Juliane, additional, Karadiakos, Christina, additional, Baronti, Lorenzo, additional, Guzzetti, Ileana, additional, Schritt, Dimitri, additional, Chen, Alan, additional, Andersson, Emma R, additional, and Petzold, Katja, additional

Published
2024
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5. RNA:RNA interaction in ternary complexes resolved by chemical probing

Author

Banijamali, Elnaz, primary, Baronti, Lorenzo, additional, Becker, Walter, additional, Sajkowska-Kozielewicz, Joanna J., additional, Huang, Ting, additional, Palka, Christina, additional, Kosek, David, additional, Sweetapple, Lara, additional, Müller, Juliane, additional, Stone, Michael D., additional, Andersson, Emma R., additional, and Petzold, Katja, additional

Published
2022
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6. RNA:RNA interaction in ternary complexes resolved by chemical probing

Author

Banijamali, Elnaz, Baronti, Lorenzo, Becker, Walter, Sajkowska-Kozielewicz, Joanna J., Huang, Ting, Palka, Christina, Kosek, David, Sweetapple, Lara, Mu¨ller, Juliane, Stone, Michael D., Andersson, Emma R., and Petzold, Katja

Abstract

RNA regulation can be performed by a second targeting RNA molecule, such as in the microRNA regulation mechanism. Selective 2′-hydroxyl acylation analyzed by primer extension (SHAPE) probes the structure of RNA molecules and can resolve RNA:protein interactions, but RNA:RNA interactions have not yet been addressed with this technique. Here, we apply SHAPE to investigate RNA-mediated binding processes in RNA:RNA and RNA:RNA-RBP complexes. We use RNA:RNAbinding by SHAPE (RABS) to investigate microRNA-34a(miR-34a) binding its mRNA target, the silent information regulator 1(mSIRT1), both with and without the Argonaute protein, constituting the RNA-induced silencing complex (RISC). We show that the seed of the mRNA target must be bound to the microRNA loaded into RISC to enable further binding of the compensatory region by RISC, while the naked miR-34ais able to bind the compensatory region without seed interaction. The method presented here provides complementary structural evidence for the commonly performed luciferase-assay-based evaluation of microRNA binding-site efficiency and specificity on the mRNA target site and could therefore be used in conjunction with it. The method can be applied to any nucleic acid-mediated RNA- or RBP-binding process, such as splicing, antisense RNA binding, or regulation by RISC, providing important insight into the targeted RNA structure.

Published
2023
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7. Efficacy of myonuclear addition may explain differential myofiber growth among resistance-trained young and older men and women

Author

Petrella, John K., Kim, Jeong-su, Cross, James M., Kosek, David J., and Bamman, Marcas M.

Subjects
Aged -- Health aspects, Aging -- Health aspects, Sarcopenia -- Analysis, Hypertrophy -- Analysis, Biological sciences
Abstract

Skeletal muscle stem (satellite) cells supporting growth/regeneration are thought to be activated and incorporated into growing myofibers by both endocrine and locally expressed autocrine/paracrine growth factors, the latter being load sensitive. We recently found that myofiber hypertrophy with resistance training is superior in young men (YM) vs. young women and older adults (Kosek DJ, Kim JS, Petrella JK, Cross JM, and Bamman MM. J Appl Physiol 101: 531-544, 2006). We hypothesized that the advanced myofiber hypertrophy in YM is facilitated by myonuclear addition in response to a milieu promoting stem cell activation. Twenty-six young (27.0 [+ or -] 1 yr, 50% women) and 26 older (63.7 [+ or -] 1 yr, 50% women) adults completed 16 wk of knee extensor resistance training. Vastus lateralis biopsies were obtained at baseline, 24 h after one bout, and after 16 wk. Muscle stem cells were identified immunohistochemically with anti-neural cell adhesion molecule (NCAM+). Muscle transcript levels of IGF-I and mechanogrowth factor (MGF) were determined by RT-PCR. Serum IGF-I, IGF-binding protein (IGFBP)-3, IGFBP-1, total and free testosterone, sex hormone-binding globulin (SHBG), and androstenedione were assessed by radioimmunoassay. Myofiber hypertrophy was twofold greater in YM vs. others, and only YM increased NCAM+ cells per 100 myofibers (49%) and myonuclei per fiber (19%) (P < 0.05). IGF-IEa mRNA was higher in young and increased acutely (29%) with summation by 16 wk (96%) (P < 0.05). MGF mRNA increased only in young after one bout (81%) and by 16 wk (85%) (P < 0.001). Circulating IGF-I was twofold higher in young, whereas IGFBP-1 was lowest in YM (P < 0.05). Among men, free testosterone was 59% higher in YM (P < 0.01). Myonuclear addition was most effectively accomplished in YM, which likely drove the superior growth. satellite cell; aging; sarcopenia; hypertrophy; strength training.

Published
2006

9. Human neuromuscular aging: Sex differences revealed at the myocellular level

Author

Roberts, Brandon M., primary, Lavin, Kaleen M., additional, Many, Gina M., additional, Thalacker-Mercer, Anna, additional, Merritt, Edward K., additional, Bickel, C. Scott, additional, Mayhew, David L., additional, Tuggle, S. Craig, additional, Cross, James M., additional, Kosek, David J., additional, Petrella, John K., additional, Brown, Cynthia J., additional, Hunter, Gary R., additional, Windham, Samuel T., additional, Allman, Richard M., additional, and Bamman, Marcas M., additional

Published
2018
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12. Změny klimatu a jejich možný dopad na mezinárodní politiku a bezpečnost v 21. století

Author

Kosek, David, Chlapcová, Ivana, and Rolenc, Jan Martin

Subjects
dopady, mezinárodní, bezpečnost, změny klimatu, 21. století
Abstract

Práce je zaměřená na problematiku klimatických změn jakožto aktuálního fenoménu, viděnou z pohledu dopadů na mezinárodní bezpečnost. Cílem práce je prezentovat téma klimatických změn právě v bezpečnostních souvislostech a nastínit, kde a jak se mohou dopady projevit. První kapitola charakterizuje pojem environmentální bezpečnosti a jeho souvislost s klimatickými změnami. V druhé kapitole je představen vývoj mezinárodních aktivit v oblasti klimatických změn. Třetí kapitola nastiňuje možné dopady, které změny klimatu na bezpečnost mohou mít a v poslední kapitole jsou rovnány postoje hlavních aktérů, jmenovitě EU a USA, a jejich rozdílnosti v přístupu k řešení. Závěr je shrnutím všech výše získaných poznatků.

Published
2007

22. Ethics and scientific publication

Author

Benos, Dale J., primary, Fabres, Jorge, additional, Farmer, John, additional, Gutierrez, Jessica P., additional, Hennessy, Kristin, additional, Kosek, David, additional, Lee, Joo Hyoung, additional, Olteanu, Dragos, additional, Russell, Tara, additional, Shaikh, Faheem, additional, and Wang, Kai, additional

Published
2005
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24. Cluster analysis to reveal differentially expressed myogenic genes during load-mediated myofiber growth in humans.

Author

Jeong-su Kim, Petrella, John K., Kosek, David J., Mayhew, David L., Cross, James M., and Bamman, Marcas M.

Subjects
GENETIC regulation, MYOBLASTS, GENE expression, ISOMETRIC exercise, CLUSTER analysis (Statistics), MESSENGER RNA, INSULIN-like growth factor-binding proteins
Abstract

We have identified a number of genes up-regulated by acute resistance loading; however, their role in myofiber hypertrophy has not been resolved. We therefore determined which "myogenic" genes were differentially expressed during growth in muscles realizing robust hypertrophy vs. those more resistant. After 16 wk of resistance training (RT), 66 humans were statistically clustered based on changes in mean fiber area (MFA, µm²) as non-responders (NR, n=17), modest responders (MR, +1111 µm², n=32), and extreme responders (XR, +2475 µm², n=17). Target mRNAs were assessed in 3 muscle biopsies (baseline and 24 h after first and last bouts). MGF increased (P<0.05) 62% in MR and 116% in XR with no change in NR. Myogenin also rose (P<0.01) in MR (49%) and XR (100%) with no change in NR. All 3 clusters (P<0.05) increased IGF-IEa, with the largest change in XR (174%). Elevations in MyoD and myf-5 (P<0.05) did not differ by cluster. Myf-6 did not change. Among the factors up-regulated during RT, only MGF and myogenin were differentially increased across clusters. Failure to increase these 2 targets in NR suggests these transcripts (and their protein products) play requisite roles during load-mediated myofiber hypertrophy. As the active IGF-I peptide is the same for MGF and IGF-IEa, mechanotransduction mechanisms that enhance local levels of this growth factor appear more effective in responders. [ABSTRACT FROM AUTHOR]

Published
2007

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