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51.
Shohei Kitahata Hinako Ichikawa Yuji Tanaka Tatsuya Inoue Kazuaki Kadonosono 《Biochemistry and Biophysics Reports》2020
Retinal pigment epithelium (RPE) cells is the outermost layer of the retina and RPE dysfunction is a key factor in the disease pathogenesis of age-related macular degeneration (AMD). Transplantation therapy using induced pluripotent stem cell (iPSC)-derived RPEs has recently received much attention as a treatment for AMD. Preserving these cells under the best possible conditions is important, and preservation methods using Y-27632 have been reported. Rho-associated coiled-coil containing kinase (ROCK) inhibitors are known to inhibit cell death, emerging as important drug candidates for stem cell differentiation and regenerative medicine. However, it has recently been shown that ROCK inhibitors may have a vasodilatory effect on human retinal arterioles, a side effect that should ideally be avoided in RPE transplantation. Although ROCK inhibitors hold great potential, optimizing efficacy while minimizing adverse reactions is critical for translation into a clinical treatment. We examined the effect of transient exposure of RPE cells to ROCK inhibitor Y-27632 to determine whether the extracellular presence of the drug is necessary for ongoing Rho/ROCK downregulation. Human RPE cells were subcultured as a suspension for 4 h in drug-free medium following exposure to Y-27632 for 2 h. A Y-27632 concentration of >10 μM improved cell survival beyond 4 h and cell proliferation in recovery culture medium. ROCK2 expression levels were specifically downregulated by Y-27632 in the Rho/ROCK signaling pathway. In conclusion, we demonstrated that the effect of Y-27632 is not dependent on its extracellular availability and can last beyond the 2 h of exposure. The lasting Rho/ROCK signaling pathway downregulation by Y-27632 suggests that RPE cell transplantation with ROCK inhibitor-free media is possible, which can minimize side effects to host tissue and have wider implications for transplantation methods requiring ROCK inhibition. 相似文献
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Nikhil N. Kulkarni Alan M. ONeill Tatsuya Dokoshi Elizabeth W.C. Luo Gerard C.L. Wong Richard L. Gallo 《The Journal of biological chemistry》2021,297(1)
Cathelicidins such as the human 37-amino acid peptide (LL-37) are peptides that not only potently kill microbes but also trigger inflammation by enabling immune recognition of endogenous nucleic acids. Here, a detailed structure–function analysis of LL-37 was performed to understand the details of this process. Alanine scanning of 34-amino acid peptide (LL-34) showed that some variants displayed increased antimicrobial activity against Staphylococcus aureus and group A Streptococcus. In contrast, different substitutions clustered on the hydrophobic face of the LL-34 alpha helix inhibited the ability of those variants to promote type 1 interferon expression in response to U1 RNA or to present U1 to the scavenger receptor (SR) B1 on the keratinocyte cell surface. Small-angle X-ray scattering experiments of the LL-34 variants LL-34, F5A, I24A, and L31A demonstrated that these peptides form cognate supramolecular structures with U1 characterized by inter-dsRNA spacings of approximately 3.5 nm, a range that has been previously shown to activate toll-like receptor 3 by the parent peptide LL-37. Therefore, while alanine substitutions on the hydrophobic face of LL-34 led to loss of binding to SRs and the complete loss of autoinflammatory responses in epithelial and endothelial cells, they did not inhibit the ability to organize with U1 RNA in solution to associate with toll-like receptor 3. These observations advance our understanding of how cathelicidin mediates the process of innate immune self-recognition to enable inert nucleic acids to trigger inflammation. We introduce the term “innate immune vetting” to describe the capacity of peptides such as LL-37 to enable certain nucleic acids to become an inflammatory stimulus through SR binding prior to cell internalization. 相似文献
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Takahiro Iwasaki Takeshi Katayama Kazuhiro Kohama Yaeta Endo Tatsuya Sawasaki 《Molecular biology of the cell》2013,24(6):748-756
In nonapoptotic cells, the phosphorylation level of myosin II is constantly maintained by myosin kinases and myosin phosphatase. During apoptosis, caspase-3–activated Rho-associated protein kinase I triggers hyperphosphorylation of myosin II, leading to membrane blebbing. Although inhibition of myosin phosphatase could also contribute to myosin II phosphorylation, little is known about the regulation of myosin phosphatase in apoptosis. In this study, we have demonstrated that, in apoptotic cells, the myosin-binding domain of myosin phosphatase targeting subunit 1 (MYPT1) is cleaved by caspase-3 at Asp-884, and the cleaved MYPT1 is strongly phosphorylated at Thr-696 and Thr-853, phosphorylation of which is known to inhibit myosin II binding. Expression of the caspase-3 cleaved form of MYPT1 that lacked the C-terminal end in HeLa cells caused the dissociation of MYPT1 from actin stress fibers. The dephosphorylation activity of myosin phosphatase immunoprecipitated from the apoptotic cells was lower than that from the nonapoptotic control cells. These results suggest that down-regulation of MYPT1 may play a role in promoting hyperphosphorylation of myosin II by inhibiting the dephosphorylation of myosin II during apoptosis. 相似文献
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Yuriko Osakabe Naoko Arinaga Taishi Umezawa Shogo Katsura Keita Nagamachi Hidenori Tanaka Haruka Ohiraki Kohji Yamada So-Uk Seo Mitsuru Abo Etsuro Yoshimura Kazuo Shinozaki Kazuko Yamaguchi-Shinozaki 《The Plant cell》2013,25(2):609-624
Osmotic adjustment plays a fundamental role in water stress responses and growth in plants; however, the molecular mechanisms governing this process are not fully understood. Here, we demonstrated that the KUP potassium transporter family plays important roles in this process, under the control of abscisic acid (ABA) and auxin. We generated Arabidopsis thaliana multiple mutants for K+ uptake transporter 6 (KUP6), KUP8, KUP2/SHORT HYPOCOTYL3, and an ABA-responsive potassium efflux channel, guard cell outward rectifying K+ channel (GORK). The triple mutants, kup268 and kup68 gork, exhibited enhanced cell expansion, suggesting that these KUPs negatively regulate turgor-dependent growth. Potassium uptake experiments using 86radioactive rubidium ion (86Rb+) in the mutants indicated that these KUPs might be involved in potassium efflux in Arabidopsis roots. The mutants showed increased auxin responses and decreased sensitivity to an auxin inhibitor (1-N-naphthylphthalamic acid) and ABA in lateral root growth. During water deficit stress, kup68 gork impaired ABA-mediated stomatal closing, and kup268 and kup68 gork decreased survival of drought stress. The protein kinase SNF1-related protein kinases 2E (SRK2E), a key component of ABA signaling, interacted with and phosphorylated KUP6, suggesting that KUP functions are regulated directly via an ABA signaling complex. We propose that the KUP6 subfamily transporters act as key factors in osmotic adjustment by balancing potassium homeostasis in cell growth and drought stress responses. 相似文献
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Chisato Yoshida Atsushi B. Tsuji Hitomi Sudo Aya Sugyo Tatsuya Kikuchi Mitsuru Koizumi Yasushi Arano Tsuneo Saga 《PloS one》2013,8(3)
Small cell lung cancer (SCLC) is an aggressive tumor and prognosis remains poor. Therefore, the development of more effective therapy is needed. We previously reported that high levels of an anti-c-kit antibody (12A8) accumulated in SCLC xenografts. In the present study, we evaluated the efficacy of two antibodies (12A8 and 67A2) for radioimmunotherapy (RIT) of an SCLC mouse model by labeling with the 90Y isotope.