The human CCR4-NOT deadenylase complex consists of at least nine enzymatic and non-enzymatic subunits. Accumulating evidence suggests that the non-enzymatic subunits are involved in the regulation of mRNA deadenylation, although their precise roles remain to be established. In this study, we addressed the function of the CNOT1 subunit by depleting its expression in HeLa cells. Flow cytometric analysis revealed that the sub G(1) fraction was increased in CNOT1-depleted cells. Virtually, the same level of the sub G1 fraction was seen when cells were treated with a mixture of siRNAs targeted against all enzymatic subunits, suggesting that CNOT1 depletion induces apoptosis by destroying the CCR4-NOT-associated deadenylase activity. Further analysis revealed that CNOT1 depletion leads to a reduction in the amount of other CCR4-NOT subunits. Importantly, the specific activity of the CNOT6L immunoprecipitates-associated deadenylase from CNOT1-depleted cells was less than that from control cells. The formation of P-bodies, where mRNA decay is reported to take place, was largely suppressed in CNOT1-depleted cells. Therefore, CNOT1 has an important role in exhibiting enzymatic activity of the CCR4-NOT complex, and thus is critical in control of mRNA deadenylation and mRNA decay. We further showed that CNOT1 depletion enhanced CHOP mRNA levels and activated caspase-4, which is associated with endoplasmic reticulum ER stress-induced apoptosis. Taken together, CNOT1 depletion structurally and functionally deteriorates the CCR4-NOTcomplex and induces stabilization of mRNAs, which results in the increment of translation causing ER stress-mediated apoptosis. We conclude that CNOT1 contributes to cell viability by securing the activity of the CCR4-NOT deadenylase.
Apoptosis ; Caspases, Initiator ; genetics ; metabolism ; Cell Survival ; Endoplasmic Reticulum ; enzymology ; Enzyme Activation ; Flow Cytometry ; HEK293 Cells ; HeLa Cells ; Humans ; Protein Subunits ; genetics ; metabolism ; RNA Stability ; RNA, Messenger ; analysis ; RNA, Small Interfering ; genetics ; metabolism ; Ribonucleases ; metabolism ; Stress, Physiological ; Transcription Factor CHOP ; genetics ; metabolism ; Transcription Factors ; genetics ; metabolism ; Transfection

Background/Aims: The objective of this study was to elucidate the histological structure of the absent microsurface patterns (MSPs) that were visualized by magnifying endoscopy with narrow-band imaging (M-NBI). Methods: The study included consecutive gastric epithelial neoplasias for which M-NBI findings and histological findings could be compared on a one-to-one basis. The lesions were classified as absent MSPs and present MSPs based on the findings obtained using M-NBI. Of the histopathological findings for each lesion that corresponded to M-NBI findings, crypt opening densities, crypt lengths, crypt opening diameters, intercrypt distances, and crypt angles were measured and compared. Results: Thirty-six lesions were included in the analysis; of these, 17 lesions exhibited absent MSP and 19 lesions exhibited present MSP. Comparing the histological measurements for absent MSPs vs. present MSPs, median crypt opening density was 0.9 crypt openings/mm vs. 4.8 crypt openings/mm (p<0.001), respectively. The median crypt length, median crypt opening diameter, median intercrypt distance, and median crypt angle were 80.0 μm vs. 160 μm (p<0.001), 40.0 μm vs. 44.2 μm (p=0.09), 572.5 μm vs. 166.7 μm (p<0.001), and 21.6 degrees vs. 15.5 degrees (p<0.001), respectively. Conclusions Histological findings showed that lesions exhibiting absent MSPs had lower crypt opening density, shorter crypt length, greater intercrypt distance, and larger crypt angle.

We conducted a questionnaire survey on shift and on-call system targeting under-forty cardiovascular surgeons and obtained responses from 35 surgeons. We report the questionnaire results.

Background/Aims: The objective of this study was to elucidate the histological structure of the absent microsurface patterns (MSPs) that were visualized by magnifying endoscopy with narrow-band imaging (M-NBI). Methods: The study included consecutive gastric epithelial neoplasias for which M-NBI findings and histological findings could be compared on a one-to-one basis. The lesions were classified as absent MSPs and present MSPs based on the findings obtained using M-NBI. Of the histopathological findings for each lesion that corresponded to M-NBI findings, crypt opening densities, crypt lengths, crypt opening diameters, intercrypt distances, and crypt angles were measured and compared. Results: Thirty-six lesions were included in the analysis; of these, 17 lesions exhibited absent MSP and 19 lesions exhibited present MSP. Comparing the histological measurements for absent MSPs vs. present MSPs, median crypt opening density was 0.9 crypt openings/mm vs. 4.8 crypt openings/mm (p<0.001), respectively. The median crypt length, median crypt opening diameter, median intercrypt distance, and median crypt angle were 80.0 μm vs. 160 μm (p<0.001), 40.0 μm vs. 44.2 μm (p=0.09), 572.5 μm vs. 166.7 μm (p<0.001), and 21.6 degrees vs. 15.5 degrees (p<0.001), respectively. Conclusions Histological findings showed that lesions exhibiting absent MSPs had lower crypt opening density, shorter crypt length, greater intercrypt distance, and larger crypt angle.

Basic procedures that cardiovascular surgeons routinely perform are rarely discussed, despite the great variability among facilities. We conducted a questionnaire survey on Extracorporeal Membrane Oxygenation (ECMO) targeting under-forty cardiovascular surgeons and obtained responses from 53 surgeons. We report the questionnaire results.