Biochimica et biophysica acta. General subjects最新文献

Background: Primary cell cultures serve as representative model systems for studying the normal physiology and biochemistry of cells. However, various methods exist for culturing these cells, and it remains unclear how these methods impact cell physiology.

Methods: Participants included both non-CRS control individuals and patients diagnosed with chronic rhinosinusitis with nasal polyps (CRSwNP). Human nasal epithelial cells (HNECs) were collected from nasal brushings and cultured under four different conditions: monolayers, air-liquid interface (ALI) cultures, Dome organoids, and ALI organoids, resulting in a total of 40 samples, including nasal brushings. We utilized the latest advances in mass spectrometry (MS) technology to gain new insights into how these different culture methods affect the protein expression of HNECs.

Results: Gene set enrichment analyses comparing nasal brushings from healthy and chronic rhinosinusitis with nasal polyps (CRSwNP) patients to HNECs cultured in various conditions showed that organoid cultures closely resemble nasal brushings. Ultrastructural analysis revealed opposing orientations of differentiated cells in Dome and ALI organoids, with ALI organoids showing increased expression of cilia-related proteins and cilia positioned on the external surface of the organoids. Both ALI and Dome organoids contained ciliated cells; however, cilia beat frequency measurements were more consistent and uniform in ALI organoids compared to Dome organoids.

Conclusions: This research could contribute to future studies aiming to improve our understanding of the pathophysiology and treatment of CRS.

Background: Sulfate in glycans often serves as a determinant of glycan-protein interactions underlying mammalian physiology. Sulfated glycoconjugates in mammals encompass proteoglycans, glycoproteins, and glycolipids, and more than 30 sulfotransferases catalyze carbohydrate sulfation.

Scope of review: We summarize the repertoire of carbohydrate sulfotransferases in humans and their relevance to human physiology, focusing on those that modify N- and O-glycans on glycoproteins and modulate glycan-protein interactions.

Major conclusions: Sulfate is indispensable in some glycan-protein interactions, whereas sialic acid can replace it in some others. The presence of both sulfate and sialic acid enhances some interactions. Regulation of glycan-protein interactions by the combination of sulfate and sialic acid has been actively investigated, while in vivo proof of such interactions may still be limited, particularly for those discovered recently.

General significance: A deeper understanding of glycan-protein interactions regulated by sulfation will advance our understanding of human physiology and contribute to improving human health.

Glycans that terminate in monosaccharides belonging to the sialic acid family of sugars regulate myriad biological processes and are increasingly being recognized as important immunoregulatory targets. These sialoglycans are biosynthesized by sialyltransferase enzymes which catalyze the transfer of CMP-sialic acid to an acceptor glycan. Many sialyltransferases display remarkable substrate tolerance and have therefore been used to incorporate chemically derivatized sialic acids into a variety of glycan structures for diverse applications involving detection and engineering of specific glycans. Sialyltransferase-mediated glycoengineering approaches have been leveraged in chemoenzymatic glycan synthesis and more recently, for sialoglycan assembly on living cell surfaces through a technique called selective exo-enzymatic labeling (SEEL). Here, we highlight the specific chemical modifications of sialic acids that have been shown compatible with diverse recombinant sialyltransferases used in both chemoenzymatic and SEEL workflows. These technologies enabled by sialyltransferases are enhancing our understanding of sialoglycan biology and are well poised to further illuminate the roles of sialoglycans in human health and disease.

Glycosylation is a critical post-translational modification of proteins. The proper function and expression of cell-surface proteins-including receptors, transporters, and cell adhesion molecules-depends on glycosylation. Among the various forms of glycosylation, core fucose applied to N-glycans exhibits distinctive characteristics and plays a significant role in numerous biological processes. Here, we focus on the molecular targets of core fucose and review their functions involved in inflammatory signaling pathways and immune systems. Cytokine receptors and toll-like receptors are important targets of core fucosylation. Additionally, core fucosylation of immunoglobulin G (IgG) plays a significant role in regulating antibody-dependent cellular cytotoxicity (ADCC). Recent studies-including ours-also indicate that the level of core fucose of IgG could serve as a valuable biomarker for monitoring inflammatory status in individuals. Modulation with monosaccharide fucose is a small event for the target molecules, but core fucose exerts a significant impact on inflammation.

The diverse repertoire of cell surface glycans, generated by the coordinated activity of glycosyltransferases and glycosidases, encodes critical biological information that is interpreted by glycan-binding proteins including galectins. Galectin-1 (GAL1), a member of this family, plays key roles across multiple hallmarks of cancer, including angiogenesis and immune evasion, driving resistance to anti-angiogenic and immunotherapeutic strategies through glycosylation-dependent mechanisms. Here, we first review the contribution of GAL1-glycan interactions to therapeutic resistance in cancer, with a particular focus on anti-angiogenic therapies and immunotherapy, and discuss the central role of glycosyltransferases in shaping these responses. While the biosynthesis of 'GAL1-permissive' glycans has been extensively characterized, the contribution of post-synthetic glycan remodeling to GAL1-driven therapeutic resistance remains uncertain. To explore mechanisms underlying GAL1-mediated resistance, we investigated whether tumor- or stromal-derived sialidases (NEU1 or NEU3) modulate sensitivity to vascular endothelial growth factor (VEGF)-targeted therapies by unmasking GAL1-binding glyco-epitopes. In the second part of the study, we present original in vivo experiments using gain- and loss-of-function approaches, demonstrating that, at least in our experimental settings, sialidases do not contribute to resistance to anti-VEGF treatment. Finally, bioinformatic analyses of patient datasets revealed differential regulation of GAL1, as well as specific glycosyltransferases, in patients responding or not to anti-VEGF or anti-PD-1 therapies. Collectively, these findings indicate that glycosyltransferases, particularly MGAT5, GCNT1, and ST6GAL1, coordinately shape the GAL1-specific glycome in settings of therapeutic resistance, whereas glycan remodeling by endogenous sialidases does not play a major role. Whether sialidases influence GAL1-dependent functions in other contexts remains to be explored.

Cancer continues to represent one of the most alarming global public health challenges, with its burden rising across both developed and developing nations. Therefore, it is essential to address this increasing global prevalence of cancer for prevention and proper cancer management which will help to reduce the cancer burden and the death caused by it. Natural compounds have gained increasing attention as potential anticancer agents due to their structural diversity, bioavailability, and comparatively lower toxicity. Among these, flavonoids, naturally occurring secondary metabolites of plants belonging to the polyphenolic class have been extensively reported to exhibit a broad spectrum of pharmacological properties, including notable anticancer activity. Human DNA topoisomerases (Topo), essential nuclear enzymes responsible for maintaining DNA topology during replication, transcription, recombination, and repair, have emerged as well-established and clinically validated targets in anticancer therapy. Several chemotherapeutic agents function by targeting these enzymes; however, their clinical application is often limited by severe toxicity and the development of drug resistance. So, this review comprehensively summarizes naturally occurring flavonoids with demonstrated anticancer potential, with a particular focus on their ability to target and modulate the activity of human DNA topoisomerases. By integrating available biochemical, cellular, and molecular evidence, this article provides critical insights into flavonoid-topoisomerase interactions and their role in cancer inhibition. The information presented herein may serve as a valuable foundation for the rational design and development of novel, flavonoid-based topoisomerase inhibitors, offering a promising alternative approach for next-generation anticancer drug discovery.

Background: Transcription factors (TFs) regulate gene expression and coordinate key cellular processes, including proliferation, differentiation, and immune responses. NFATc1 is a central regulator of immune signaling, while c-Jun mediates stress and oncogenic pathways. Their cooperative DNA binding is critical for controlling complex transcriptional programs, yet existing approaches inadequately capture the real-time kinetics underlying these interactions. This study addresses the lack of dynamic characterization of cooperative NFATc1 and c-Jun DNA binding using surface plasmon resonance (SPR).

Results: Using SPR, we quantified the individual and cooperative DNA-binding kinetics of NFATc1 and c-Jun. NFATc1 binds DNA with a dissociation constant (KD) of (4.11 ± 0.07) × 10^-7 M, while c-Jun shows a slightly stronger affinity KD = (1.95 ± 0.03) × 10^-7 M. Not surprisingly, when forming a heterodimeric complex, the NFATc1-c-Jun binding affinity further lowers the KD = (1.63 ± 0.17) × 10^-7 M, indicating cooperative interaction. More important, kinetic analysis revealed that the association rate (ka) increased more than threefold, from (2.44 ± 0.10) × 10⁵ M^-1 s^-1 to (8.29 ± 0.19) × 10⁵ M^-1 s^-1, while dissociation kinetics remained dynamic. These results demonstrate that NFATc1 facilitates c-Jun recruitment, enhancing cooperative DNA engagement. Together, the findings highlight the unique ability of SPR to resolve cooperative TF-DNA interactions with high temporal precision, providing insights not attainable through conventional techniques.

Significance: This study reveals a kinetic mechanism underlying NFATc1-c-Jun synergistic gene regulation and demonstrates the power of SPR to resolve cooperative TF-DNA interactions in real time, bridging static structural data with dynamic transcriptional regulation.