FEBS Open Bio最新文献

To mark the International Day of Women and Girls in Science 2025, we invited Prof Asifa Akhtar, Vice President of the Max Planck Society's Biology and Medicine section, Director at the Max Planck Institute of Immunobiology and Epigenetics in Freiburg, Honorary Professor at the Albert Ludwigs University and recipient of the 2025 FEBS | EMBO Women in Science Award to meet and chat with Klaudia Jaczynska, final year PhD student at Jose Rizo's laboratory in UT Southwestern Medical Center, Dallas, and 2024 FEBS Open Bio Article Prize winner. We invited them to talk about challenges limiting equal representation in science, technology, engineering and mathematics, initiatives to foster supportive environments as a research institute and the importance of highlighting diverse examples of success.

Dimethyl fumarate (DMF) is an anti-inflammatory and immunoregulatory medication used to treat multiple sclerosis (MS) and psoriasis. Its skin sensitization property precludes its topical use, which is unfortunate for the treatment of psoriasis. Isosorbide di-(methyl fumarate) (IDMF), a novel derivative of DMF, was synthesized to circumvent this adverse reaction and unlock the potential of topical delivery, which could be useful for treating psoriasis in the subpopulation of psoriatic MS patients, as well as in the general population. Here, we compared its therapeutic potential of this non-sensitizing derivative with DMF and its therapeutic version Diroximel in three skin- and neuroinflammation models: the lck-GFP zebrafish, activated BV-2 murine microglia and human T-lymphocyte Jurkat cell line. The results provide a comparative evaluation of the bioactivity of these three related chemical entities in models relevant to skin and neuroinflammation and expose several therapeutic advantages unique to IDMF.

FAM136A deficiency has been associated with Ménière's disease. However, the underlying mechanism of action of this protein remains unclear. We hypothesized that FAM136A functions in maintaining mitochondria, even in HepG2 cells. To better characterize FAM136A function, we analyzed the cellular response caused by its depletion. FAM136A depletion induced reactive oxygen species (ROS) and reduced both mitochondrial membrane potential and ATP production. However, cleaved caspase-9 levels did not increase significantly. We next investigated why the depletion of FAM136A reduced the mitochondrial membrane potential and ATP production but did not lead to apoptosis. Depletion of FAM136A induced the mitochondrial unfolded protein response (UPR^mt) and the expression levels of gluconeogenic phosphoenolpyruvate carboxykinases (PCK1 and PCK2) and ketogenic 3-hydroxy-3-methylglutaryl-CoA synthases (HMGCS1 and HMGCS2) were upregulated. Furthermore, depletion of FAM136A reduced accumulation of holocytochrome c synthase (HCCS), a FAM136A interacting enzyme that combines heme to apocytochrome c to produce holocytochrome c. Notably, the amount of heme in cytochrome c did not change significantly with FAM136A depletion, although the amount of total cytochrome c protein increased significantly. This observation suggests that greater amounts of cytochrome c remain unbound to heme in FAM136A-depleted cells.

Malaria, a life-threatening disease caused by Plasmodium parasites, continues to pose a significant global health threat, with nearly 250 million infections and over 600 000 deaths reported annually by the WHO. Fighting malaria is particularly challenging partly due to the complex life cycle of the parasite. However, technological breakthroughs such as the development of the nucleoside-modified mRNA lipid nanoparticle (mRNA-LNP) vaccine platform, along with the discovery of novel conserved Plasmodium antigens such as the E140 protein, present new opportunities in malaria prevention. Importantly, production of recombinant proteins for malaria vaccine evaluation by serological assays often represents an additional hurdle because many Plasmodium proteins are complex and often contain transmembrane domains that make production and purification particularly difficult. This research protocol provides a step-by-step guide for the production and purification of P. berghei and P. vivax E140 protein fragments that can be used to test humoral immune responses against this novel malaria vaccine target. We demonstrate that the purified proteins can be successfully used in enzyme-linked immunosorbent assay (ELISA) to evaluate antigen-specific binding antibody responses in sera obtained from E140 mRNA-LNP-vaccinated mice. Therefore, these proteins can contribute to the development and evaluation of E140-based malaria vaccines.

Neurotransmitter release is triggered in microseconds by the two C₂ domains of the Ca²⁺ sensor synaptotagmin-1 and by SNARE complexes, which form four-helix bundles that bridge the vesicle and plasma membranes. The synaptotagmin-1 C₂B domain binds to the SNARE complex via a 'primary interface', but the mechanism that couples Ca²⁺-sensing to membrane fusion is unknown. Widespread models postulate that the synaptotagmin-1 Ca²⁺-binding loops accelerate membrane fusion by inducing membrane curvature, perturbing lipid bilayers or helping bridge the membranes, but these models do not seem compatible with SNARE binding through the primary interface, which orients the Ca²⁺-binding loops away from the fusion site. To test these models, we performed molecular dynamics simulations of SNARE complexes bridging a vesicle and a flat bilayer, including the synaptotagmin-1 C₂ domains in various configurations. Our data do not support the notion that insertion of the synaptotagmin-1 Ca²⁺-binding loops causes substantial membrane curvature or major perturbations of the lipid bilayers that could facilitate membrane fusion. We observed membrane bridging by the synaptotagmin-1 C₂ domains, but such bridging or the presence of the C₂ domains near the site of fusion hindered the action of the SNAREs in bringing the membranes together. These results argue against models predicting that synaptotagmin-1 triggers neurotransmitter release by inducing membrane curvature, perturbing bilayers or bridging membranes. Instead, our data support the hypothesis that binding via the primary interface keeps the synaptotagmin-1 C₂ domains away from the site of fusion, orienting them such that they trigger release through a remote action.

Previous studies have suggested that women with higher follicle-stimulating hormone (FSH) levels have a greater incidence of osteoarthritis (OA) compared to women with lower FSH despite normal estrogen levels. Our previous studies also showed that FSH has a negative effect on cartilage in postmenopausal OA. However, no studies have investigated the effect of FSH on the synovium. Here, we showed that the FSH receptor (FSHR) is expressed on RAW264.7 cells and BMDM (Bone Marrow-Derived Macrophages), and found that FSH stimulation promotes the production and secretion of inflammatory cytokines in synovial macrophages. In RAW264.7 cells, FSH stimulation enhances phosphorylation and nuclear translocation of P65, suggesting the activation of NFκB signaling, while the knockdown of FSHR eliminates the proinflammatory effect of FSH. To further validate these results, we used an ovariectomy mouse model supplemented with FSH and estrogen, and a mouse model with FSH neutralization. We noted that FSHR was expressed on mouse synovial joint membranes. Furthermore, in ovariectomy mice supplemented with estrogen and treated with FSH, synovial macrophages were significantly increased, while the opposite was the case in the FSH neutralizing group, which suggest that FSH triggers an inflammatory response in the synovial tissue in mice. Taken together, our results indicate that FSH is an important regulator in synovial inflammation via NFκB signaling activation and, to some extent, appears to accelerate the development of osteoarthritis.

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.