1,829 research outputs found
Targeting Integrin-β1 Impedes Cytokine-Induced Osteoclast Differentiation: A Potential Pharmacological Intervention in Pathological Osteolysis
Purpose: To examine whether integrin-β1 is essential for osteoclast differentiation and function and if it can be targeted for pharmacological intervention in pathological osteolysis.Methods: Control and Integrin-β1 knockdown RAW 264.7 cells were treated with receptor activator of nuclear factor kappa-B (RANKL) or TNF-α and evaluated for osteoclast differentiation. Osteoclast differentiation and function were evaluated by marker protein analysis, tartrate-resistant acid phosphatase (TRAP) and resorption assays. Furthermore, downstream molecular signaling analysis was probed using small molecule inhibitors and blocking antibodies, and evaluated by immunoblotting.Results: Integrin-β1 knockdown cells showed reduced osteoclast differentiation following TNF-α treatment while no change was seen after RANKL treatment (p < 0.05). Immunoblot-based molecular signaling analysis showed involvement of MAPK kinase signaling in mediating TNF-α/integrin-β1- induced osteoclastogenesis. Finally, when MAPK kinase inhibitor (2.5 and 5 μM; p < 0.05) and integrin- β1 blocking antibody (2.5 and 5 μg/mL; p < 0.05) was used to specifically attenuate TNF-α induced osteoclastogenesis, no change was observed in RANKL-induced osteoclast formation.Conclusion: The data obtained highlight the role of integrin-β1 in TNF-α-induced osteoclastogenesis, but not in RANKL pathway. Given that, inflammatory cytokine secretions such as TNF-α are progressively implicated in pathological osteolysis, targeting this pathway may attenuate osteolysis in pathological bone tissues.Keywords: Osteoclast differentiation, Integrin-β1, Receptor activator of nuclear factor kappa-B, TNFalpha, Mitogen activated protein kinase, Cytokines, Skeletal diseas
An efficient DNA isolation method for tropical plants
Due to interfering components such as polysacharrides, polyphenols, etc, DNA isolation from tropical plants had been challenging. We developed a safe, universal and efficient DNA extraction method, which yielded high-quality DNA from 10 tropical plants including cassava, rubber tree, banana, etc. In the extraction buffer, 2 M NaCl was used to provide a high ionic strength reaction environment, ethylenediaminetetraacetic acid (EDTA), lauroyl sarcosine (LSS) and cetyl trimethyl ammonium bromide (CTAB) could inhibit DNase activity effectively, polyvinylpolypyrrolidone (PVPP) produced a deoxidized reaction environment, and borax enhanced the precipitation of interfering compounds. Ordinary reagents like β-mercaptoethanol, chloroform and phenol were unnecessary in this protocol, which made it safe and friendly to use. PCR and EcoR I enzyme restriction digestion results show that the obtained DNA is good enough for downstream analysis. In conclusion, this protocol is expected to be a preferable DNA extraction protocol for tropical plants.Keywords: DNA extraction, tropical plants, cetyl trimethyl ammonium bromide (CTAB)African Journal of Biotechnology Vol. 12(19), pp. 2727-273
Docosahexaenoic acid has influence on action potentials and transient outward potassium currents of ventricular myocytes
<p>Abstract</p> <p>Background</p> <p>There are many reports about the anti-arrhythmic effects of ω-3 polyunsaturated fatty acids, however, the mechanisms are still not completely delineated. The purpose of this study was to investigate the characteristics of action potentials and transient outward potassium currents (I<sub>to</sub>) of Sprague-Dawley rat ventricular myocytes and the effects of docosahexaenoic acid (DHA) on action potentials and I<sub>to</sub>.</p> <p>Methods</p> <p>The calcium-tolerant rat ventricular myocytes were isolated by enzyme digestion. Action potentials and I<sub>to </sub>of epicardial, mid-cardial and endocardial ventricular myocytes were recorded by whole-cell patch clamp technique.</p> <p>Results</p> <p><b>1.</b> Action potential durations (APDs) were prolonged from epicardial to endocardial ventricular myocytes (<it>P </it>< 0.05). <b>2.</b> I<sub>to </sub>current densities were decreased from epicardial to endocardial ventricular myocytes, which were 59.50 ± 15.99 pA/pF, 29.15 ± 5.53 pA/pF, and 12.29 ± 3.62 pA/pF, respectively at +70 mV test potential (<it>P </it>< 0.05). <b>3.</b> APDs were gradually prolonged with the increase of DHA concentrations from 1 μmol/L to 100 μmol/L, however, APDs changes were not significant as DHA concentrations were in the range of 0 μmol/L to 1 μmol/L. <b>4.</b> I<sub>to </sub>currents were gradually reduced with the increase of DHA concentrations from 1 μmol/L to 100 μmol/L, and its half-inhibited concentration was 5.3 μmol/L. The results showed that there were regional differences in the distribution of action potentials and I<sub>to </sub>in rat epicardial, mid-cardial and endocardial ventricular myocytes. APDs were prolonged and I<sub>to </sub>current densities were gradually reduced with the increase of DHA concentrations.</p> <p>Conclusion</p> <p>The anti-arrhythmia mechanisms of DHA are complex, however, the effects of DHA on action potentials and I<sub>to </sub>may be one of the important causes.</p
Coherent phonon Rabi oscillations with a high frequency carbon nanotube phonon cavity
Phonon-cavity electromechanics allows the manipulation of mechanical
oscillations similar to photon-cavity systems. Many advances on this subject
have been achieved in various materials. In addition, the coherent phonon
transfer (phonon Rabi oscillations) between the phonon cavity mode and another
oscillation mode has attracted many interest in nano-science. Here we
demonstrate coherent phonon transfer in a carbon nanotube phonon-cavity system
with two mechanical modes exhibiting strong dynamical coupling. The
gate-tunable phonon oscillation modes are manipulated and detected by extending
the red-detuned pump idea of photonic cavity electromechanics. The first- and
second-order coherent phonon transfers are observed with Rabi frequencies 591
kHz and 125 kHz, respectively. The frequency quality factor product
fQ_m~2=10^12 Hz achieved here is larger thank k_B T_base/h, which may enable
the future realization of Rabi oscillations in the quantum regime
Strongly-coupled nanotube electromechanical resonators
Coupling an electromechanical resonator with carbon-nanotube quantum dots is
a significant method to control both the electronic charge and the spin quantum
states. By exploiting a novel micro-transfer technique, we fabricate two
strongly-coupled and electrically-tunable mechanical resonators on a single
carbon nanotube for the first time. The frequency of the two resonators can be
individually tuned by the bottom gates, and strong coupling is observed between
the electron charge and phonon modes of each resonator. Furthermore, the
conductance of either resonator can be nonlocally modulated by the phonon modes
in the other resonator. Strong coupling is observed between the phonon modes of
the two resonators, which provides an effective long distance electron-electron
interaction. The generation of phonon-mediated-spin entanglement is also
theoretically analyzed for the two resonators. This strongly-coupled nanotube
electromechanical resonator array provides an experimental platform for future
studies of the coherent electron-phonon interaction, the phonon mediated
long-distance electron interaction, and entanglement state generation
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