FEBS Open Bio最新文献

Oxidation of lactate under anaerobic dark fermentative conditions poses an energetic problem. The redox potential of the lactate/pyruvate couple is too electropositive to reduce the physiological electron carriers NAD(P)⁺ or ferredoxin. However, the thermophilic, anaerobic, and acetogenic model organism Moorella thermoacetica can grow on lactate but was suggested to have a NAD⁺-dependent lactate dehydrogenase (LDH), based on enzyme assays in cell-free extract. LDHs of thermophilic and anaerobic bacteria are barely characterized but have a huge biotechnological potential. Here, we have purified the LDH from M. thermoacetica by classical chromatography. Lactate-dependent NAD⁺ reduction was observed with high rates. Electron bifurcation was not observed. At pH 8 and 65 °C, the LDH had a specific activity of 60 U·mg^-1 for lactate oxidation, but NADH-driven pyruvate reduction was around four times faster with an activity of 237 U·mg^-1. Since lactate formation is preferred by the enzyme, further modifications of the LDH can be suggested to improve the kinetics of this enzyme making it a promising candidate for biotechnological applications.

FEBS Open Bio remains dedicated to serving the scientific community by ensuring rapid publication of rigorous science and pioneering initiatives to support researchers. In this editorial, we reflect on a year of achievements, and look forward to the new developments planned for 2025.

Effective therapies have yet to be established for pancreatic ductal adenocarcinomas (PDAC) even though it is the most aggressive cancer. In the present study, PDAC was analyzed using novel rat mAbs against membrane proteins in conjunction with flow cytometry and immunohistochemistry. Human epidermal growth receptor (HER)1-4, mesenchymal to epithelial transition factor (MET), sphingosine-1-phospahate receptor 1 (S1PR1), l-type amino acid transporter 1 (LAT1), system x^- _c transporter (xCT), alanine-serine-cysteine transporter (ASCT2), cationic amino acid transporter 1 (CAT1) and variant CD44 (CD44v) were expressed at high frequencies in both in vitro and in vivo PDAC. Internalization of membrane proteins by mAbs and growth inhibition by toxin-linked mAbs were demonstrated in many PDAC cell lines, and mAbs against S1PR1, ASCT2, HER3 and CD44v inhibited the growth of xenografted MIA PaCa-2 PDAC cells. Furthermore, CD44v-high PDAC showed high mRNA expression of HER1-3, MET and CD44v, and was correlated with poor prognosis. Taken together, our results suggest that CD44v, S1PR1, HER3, MET and the above-mentioned cancer-associated amino acid transporters might be promising targets for the diagnosis and treatment of PDAC.

MST2 (STK3) is a major upstream kinase in the Hippo signalling pathway, an evolutionary conserved pathway in regulation of organ size, self-renewal and tissue homeostasis. Its downstream effectors are the transcriptional regulators YAP and TAZ. This pathway is regulated by a variety of factors, such as substrate stiffness or cell-cell contacts. Using a yeast two-hybrid screen, we detected a novel interaction between the kinases MST2 and CDK5, which we further confirmed by co-immunoprecipitation experiments. Cyclin-dependent kinase 5 (CDK5) is an unusual member of the family of cyclin-dependent kinases, involved in tumour growth and angiogenesis. Although a link between CDK5 and Hippo has been previously postulated, the mode of action is still elusive. Here, we show that knockdown of CDK5 causes reduced transcriptional activity of YAP and that CDK5 influences the phosphorylation levels of the Hippo upstream kinase LATS1. Moreover, a phosphoproteomics approach revealed that CDK5 interferes with the phosphorylation of DLG5, another upstream kinase, which regulates the Hippo pathway. Hence, CDK5 seems to act as a signalling hub for integrating the Hippo pathway and other signalling cascades. These interactions might have important implications for the use of CDK5 inhibitors, which are already in clinical use for tumour diseases.

Mice are one of the most common biological models for laboratory use. However, wild-type mice are not susceptible to COVID-19 infection due to the low affinity of mouse ACE2, the entry protein for SARS-CoV-2. Although mice with human ACE2 (hACE2) driven by Ace2 promoter reflect its tissue specificity, these animals exhibit low ACE2 expression, potentially limiting their fidelity in mimicking COVID-19 manifestations and their utility in viral studies. Here, we created and compared hACE2 mouse models generated with different strategies. Our findings show that distinct β-globin insertion within hACE2 cassette significantly influences its expression, with downstream placement enhancing transcription. Moreover, optimizing hACE2 codons (opt-hACE2) improves translation efficiency in multiple tissues. Notably, opt-hACE2 mice displayed more active immune responses and severe COVID-19 phenotypes following SARS-CoV-2 challenge compared to other models. Our study demonstrates the dual regulatory role of β-globin element in transgene transcription and suggests that opt-hACE2 mice might serve as valuable tools for SARS-CoV-2 research.

Retraction: R. Inoue, K. Kamimura, T. Nagoya, N. Sakai, T. Yokoo, R. Goto, K. Ogawa, Y. Shinagawa-Kobayashi, Y. Watanabe-Mori, A. Sakamaki, S. Abe, H. Kamimura, N. Miyamura, H. Nishina, and S. Terai, "Effect of a Neural Relay on Liver Regeneration in Mice: Activation of Serotonin Release from the Gastrointestinal Tract," FEBS Open Bio 8, no. 3 (2018): 449-460, https://doi.org/10.1002/2211-5463.12382. The above article, published online on 16 January 2018, in Wiley Online Library (http://onlinelibrary.wiley.com/),has been retracted by agreement between the journal Editor-in-Chief, Miguel A. De la Rosa; FEBS Press; and John Wiley and Sons Ltd. The journal received a report from a third party which indicated that the Day 2 and Day 4 panels in Figure 3A had been duplicated and rotated. Additional investigation by the journal discovered multiple inappropriate image duplications and overlaps in Figure 6A. The authors responded to an inquiry by the journal, confirmed that images had been duplicated in both figures, and provided what was labelled as the correct data. Following receipt of the authors' explanation and new data, the journal requested an investigation by the authors' institution. The institutional investigation reported that there was insufficient evidence of intentional image manipulation and concluded that the image duplications were due to errors in image preparation by the authors. However, given the extent of the identified issues, the editors have lost confidence in the data presented and consider the conclusions of this manuscript substantially compromised. As a result, the Editor-in-Chief, FEBS Press, and John Wiley and Sons Ltd. have determined that a retraction is necessary. The authors disagree with the retraction.

Mitophagy, a selective clearance of damaged or superfluous mitochondria via autophagy machinery and lysosomal degradation, is an evolutionarily conserved process essential for various physiological functions, including cellular differentiation and immune responses. Defects in mitophagy are implicated in numerous human diseases, such as neurodegenerative disorders, cancer, and metabolic conditions. Despite significant advancements in mitophagy research over recent decades, novel and robust methodologies are necessary to elucidate its molecular mechanisms comprehensively. In this study, we present a detailed protocol for quantitatively assessing mitophagy through flow cytometry using a mitochondria-targeted fluorescent mitophagy receptor, GFP-BNIP3L/NIX. This method offers a rapid alternative to conventional microscopy or immunoblotting techniques for analyzing mitophagy activity. Additionally, this approach can theoretically be adapted to utilize any fluorescent-tagged selective autophagy receptor, enabling the direct and rapid analysis of various types of receptor-mediated selective autophagy.

Hepatocellular carcinoma remains a significant threat to human health. Recent studies have found that the intake of cellular cholesterol contributes to the development and progression of hepatocellular carcinoma, although the exact mechanisms remain unclear. Our analysis of transcriptomic and proteomic databases has identified increased mRNA and protein expression levels of NPC1, a cholesterol intracellular transporter protein, in hepatocellular carcinoma tissues. This increase is significantly associated with a worse prognosis for patients. To corroborate these findings, we performed immunohistochemical staining of NPC1 on liver tissue samples from patients, revealing significantly higher expression levels of NPC1 in hepatocellular carcinoma tissues compared to normal tissues. Subsequent investigations have revealed that NPC1 expression does not significantly influence the proliferation of hepatocellular carcinoma cells in vitro. However, it has a substantial inhibitory effect on the progression of hepatocellular carcinoma tumors when observed in vivo. Utilizing flow cytometry to monitor cellular changes within the tumor microenvironment has led us to discover that NPC1 plays a crucial role in the regulation of neutrophil recruitment within the tumor. Using further neutrophil depletion experiments, we determined that the role of NPC1 in advancing hepatocellular carcinoma progression truly relies on neutrophils. These observations are further reinforced by a comprehensive analysis of clinical databases alongside immunohistochemistry findings. In conclusion, our research suggests that NPC1's overexpression could contribute to hepatocellular carcinoma progression by promoting neutrophil recruitment, positioning NPC1 as a promising new biomarker and therapeutic target for hepatocellular carcinoma.

Proper glycemic control is crucial for patient management in critical care, including perioperative care, and can influence patient prognosis. Blood glucose concentration determines insulin secretion and sensitivity and affects the intricate balance between the glucose metabolism. Human and other animal studies have demonstrated that perioperative drugs, including volatile anesthetics and intravenous anesthetics, affect glucose-stimulated insulin secretion (GSIS). Dexmedetomidine (DEX) decreases insulin release and affects glucose metabolism; however, the specific mechanism underlying this phenomenon remains largely unknown. Thus, we investigated the effect and mechanism of DEX on insulin secretion using mouse and rat pancreatic β-cell-derived MIN6 and INS-1 cell lines and primary pancreatic β-cells/islets extracted from mice. The amount of insulin secreted into the culture medium was determined using an enzyme-linked immunosorbent assay. Cell viability, cytotoxicity, and electrophysiological effects were investigated. Clinically relevant doses of DEX suppressed GSIS in MIN6 cells, INS-1 cells, and pancreatic β-cells/islets. Furthermore, DEX suppressed insulin secretion facilitated by insulinotropic factors. There was no significant difference in oxygen consumption rate, intracellular ATP levels, or caspase-3/7 activity. Electrophysiological evaluation using the patch-clamp method showed that DEX did not affect ATP-sensitive potassium (K_ATP) channels, voltage-dependent potassium channels, or voltage-gated calcium channels. We demonstrated that clinically relevant doses of DEX significantly suppressed GSIS. These findings suggest that DEX inhibits a signaling pathway via α2-adrenoceptor or insulin vesicle exocytosis, resulting in GSIS suppression. Our results support the hypothesis that DEX suppresses insulin secretion and reveal some underlying mechanisms.