Biomolecules

16 pages, 798 KB

Open AccessArticle

Virulence Reduction in Yersinia pestis by Combining Delayed Attenuation with Plasmid Curing

by Svetlana V. Dentovskaya, Rima Z. Shaikhutdinova, Mikhail E. Platonov, Nadezhda A. Lipatnikova, Elizaveta M. Mazurina, Tat’yana V. Gapel’chenkova, Pavel Kh. Kopylov, Sergei A. Ivanov, Alexandra S. Trunyakova, Anastasia S. Vagaiskaya and Andrey P. Anisimov

Biomolecules 2026, 16(1), 40; https://doi.org/10.3390/biom16010040 (registering DOI) - 25 Dec 2025

Abstract

Yersinia pestis caused the three plague pandemics that claimed more than two hundred million human lives. There is still no vaccine that meets all WHO requirements, and many researchers continue to develop plague vaccines using various technological platforms. For example, researchers led by [...] Read more.

Yersinia pestis caused the three plague pandemics that claimed more than two hundred million human lives. There is still no vaccine that meets all WHO requirements, and many researchers continue to develop plague vaccines using various technological platforms. For example, researchers led by Roy Curtiss 3rd have developed a new approach to achieve controlled, delayed attenuation of bacterial pathogens. Mutants generated using this method were superior in protecting Y. pestis-infected mice immunized with strains generated using traditional gene knockout. However, further studies are needed to determine the safety and efficacy of these delayed-attenuated strains in other mammalian species in order to extrapolate on humans the data obtained in accordance with the FDA Animal Rule. Three Y. pestis strains, a Δcrp mutant, a mutant with arabinose-dependent regulated crp expression (araC P_BAD crp) or an araC P_BAD crp mutant cured of plasmid pPst were derived from virulent wild-type strain 231. To evaluate the safety, outbred mice or guinea pigs were immunized subcutaneously with serial tenfold dilutions of mutated strains. For vaccine studies, immunized animals were subcutaneously challenged with 200 LD₁₀₀ (lethal dose in all exposed subjects) of the wild-type Y. pestis strain. The challenge caused the death of 100% of naïve animals in controls. The Y. pestis strain 231Δcrp was nonlethal in mice at a dose of 10⁷ CFs. The LD₅₀ of the 231Δcrp strain in guinea pigs increased by at least 10⁷-fold compared to that of the wild-type strain. The LD₅₀s of the 231P_BAD-crp mutant in mice and guinea pigs were approximately 10⁴-fold and 10⁷-fold higher than those of Y. pestis 231, respectively. The 231P_BAD-crp(pPst¯) strain did not cause death in mice (LD₅₀ > 10⁷ CFU) and guinea pigs (LD₅₀ > 10⁹ CFU) when administered subcutaneously and was capable of inducing intense protective immunity in both species of laboratory animals. Our research has shown once again the necessity of balance between safety and effectiveness demonstrating the feasibility of further investigation of crp mutants as promising candidate plague vaccines. Full article

(This article belongs to the Section Molecular Biology)

29 pages, 1479 KB

Open AccessReview

Immunological Causes of Infertility: Diagnostic Perspectives

by Aleksandra M. Kicińska, Radosław B. Maksym and Grzegorz Szewczyk

Biomolecules 2026, 16(1), 39; https://doi.org/10.3390/biom16010039 (registering DOI) - 25 Dec 2025

Abstract

From an immunological perspective, infertility mechanisms encompass not only fertilization but also implantation, as well as both early and late pregnancy loss. Growing attention is being directed towards the influence of systemic disorders on reproductive outcomes. The immune system plays a fundamental and [...] Read more.

From an immunological perspective, infertility mechanisms encompass not only fertilization but also implantation, as well as both early and late pregnancy loss. Growing attention is being directed towards the influence of systemic disorders on reproductive outcomes. The immune system plays a fundamental and regulatory role in human reproduction. Immunological factors may affect multiple stages of this process, potentially justifying their inclusion in extended diagnostic pathways. The impact of autoimmunity and the presence of various antibodies on reproductive functions is discussed. Special attention is given to the immunomodulatory role of progesterone in reproduction and a state of impaired progesterone action—luteal deficiency. Endometriosis is also highlighted as a disorder both associated with infertility and underpinned by a strong immunological basis. The usefulness of assessing lymphocyte subpopulation balance, cytokine profiles, and Th1/Th2 immune response in the diagnostic work-up of infertility is addressed. Furthermore, the prospect for a role of local and systemic infections, subclinical inflammation and microbial colonization is shown. Tests applied in the evaluation of implantation and placental development disorders are discussed. Adequate immunological diagnostics and accurate identification of the underlying causes of infertility facilitate effective therapeutic strategies and can substantially increase the likelihood of achieving a successful pregnancy. Full article

(This article belongs to the Special Issue Molecular Aspects of Female Infertility)

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20 pages, 8968 KB

Open AccessArticle

Methyl Protodioscin Promotes Ferroptosis of Prostate Cancer Cells by Facilitating Dissociation of RB1CC1 from the Detergent-Resistant Membranes and Its Nuclear Translocation

by Ruonan Wang, Chaoyu Hu, Yi Zhao, Shuhan Wu, Shujuan Cao, Leiming Xu, Dengke Yin and Song Tan

Biomolecules 2026, 16(1), 38; https://doi.org/10.3390/biom16010038 (registering DOI) - 25 Dec 2025

Abstract

Methyl protodioscin (MPD), a furostanol saponin found in the rhizomes of Dioscorea plants, has been shown to effectively inhibit proliferation of prostate cancer cells in vitro and in vivo. However, the mechanism underlying this inhibitory action remains unclear. To elucidate the mechanism, we [...] Read more.

Methyl protodioscin (MPD), a furostanol saponin found in the rhizomes of Dioscorea plants, has been shown to effectively inhibit proliferation of prostate cancer cells in vitro and in vivo. However, the mechanism underlying this inhibitory action remains unclear. To elucidate the mechanism, we used mass spectrometry to analyze protein rearrangements in detergent-resistant membranes (DRMs). Ferroptosis-related factors were identified in cells in vitro and in vivo. MPD induced the expression of acyl-CoA synthetase long chain family member 4 and reduced expression levels of glutathione peroxidase 4 and solute carrier family 7 member 11. Following MPD treatment, RB1-inducible coiled-coil 1 (RB1CC1) dissociated from DRMs and translocated from the cytoplasm to the nucleus. This translocation induced the expression of ferroptosis-related protein coiled-coil-helix-coiled-coil-helix domain containing 3, promoting ferroptosis in prostate cancer cells. As the nuclear translocation of RB1CC1 was promoted by the JNK signaling pathway, SP600125, a JNK inhibitor, prevented the MPD-induced RB1CC1 nuclear translocation. In summary, MPD induced the dissociation of RB1CC1 from DRMs and its subsequent nuclear translocation, contributing to ferroptosis of prostate cancer cells. Full article

(This article belongs to the Special Issue Cellular Signaling in Cancer)

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40 pages, 8001 KB

Open AccessArticle

Steric and Electronic Effects in the Enzymatic Catalysis of Choline-TMA Lyase

by Valentin Gogonea and Stanley L. Hazen

Biomolecules 2026, 16(1), 37; https://doi.org/10.3390/biom16010037 (registering DOI) - 25 Dec 2025

Abstract

An important microbial enzymatic pathway in the gut is choline/phosphatidylcholine degradation in which intestinal microbes utilize dietary choline to produce TMA via the choline utilization cluster polypeptide C (CutC) enzyme, a member of the glycyl radical enzyme family. Our goal in this theoretical [...] Read more.

An important microbial enzymatic pathway in the gut is choline/phosphatidylcholine degradation in which intestinal microbes utilize dietary choline to produce TMA via the choline utilization cluster polypeptide C (CutC) enzyme, a member of the glycyl radical enzyme family. Our goal in this theoretical work was to study the reaction mechanism and elucidate how the enzyme environment (steric and electronic) modulates the reaction path. Dissecting the effect of the enzyme environment on the reaction mechanism and shedding light on how steric and electronic effects affect the reaction path is an insightful and significant contribution of this work. Our theoretical results suggest that the final product of enzyme catalysis might be carbinolamine and not TMA and acetaldehyde. In addition, we found out that Glu₄₉₁ plays the role of a base in this reaction (a disputed fact) by temporarily abstracting a proton from the hydroxylic group of choline sometime during the reaction—with the proton transfer being critical for the reaction to proceed to completion. We also found that the choice of computational protocol not only alters the reaction energetics but can change the reaction path by creating new intermediates and transition states or eliminating existing ones. Full article

(This article belongs to the Section Enzymology)

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16 pages, 3513 KB

Open AccessArticle

Melatonin Administration Attenuates High-Fat-Diet-Induced Renal Damage in Wistar Rats

by Olesia Kalmukova, Anastasiia Zavora, Alena Cherezova, Olexiy Savchuk, Mariia Stefanenko, Mykhailo Fedoriuk, Adam C. Jones, Valentyn Nepomnyashchy, Mykola Dzerzhynskyi, Marharyta Semenikhina, Daria V. Ilatovskaya and Oleg Palygin

Biomolecules 2026, 16(1), 36; https://doi.org/10.3390/biom16010036 (registering DOI) - 25 Dec 2025

Abstract

Obesity is a major contributor to kidney injury, in part through circadian rhythms disruption and oxidative stress. Melatonin, a circadian clock regulator, has been proposed as a protective agent against metabolic and renal complications. We investigated the effects of chronic melatonin supplementation on [...] Read more.

Obesity is a major contributor to kidney injury, in part through circadian rhythms disruption and oxidative stress. Melatonin, a circadian clock regulator, has been proposed as a protective agent against metabolic and renal complications. We investigated the effects of chronic melatonin supplementation on kidney injury and circadian regulation in a rat obesity model. We hypothesized that melatonin administration ameliorates kidney injury induced by a high-calorie diet. Male Wistar rats were fed a normal or hypercaloric diet for six weeks, followed by seven weeks of vehicle or melatonin treatment (30 mg/kg/day in drinking water); biometric parameters and renal injury were assessed. Obese rats exhibited increased visceral adiposity, elevated resistin, renal hypertrophy, fibrosis, tubular degeneration, and glomerular injury, accompanied by higher KIM-1 levels. Melatonin attenuated renal fibrosis, reduced KIM-1, TGFβ, and TNFR1 levels, improved proximal tubule and glomerular damage, and lowered adipose TNF-α levels in the obese groups. In lean controls, melatonin increased nuclear BMAL1 levels, while in obese rats this effect was blunted; of note, BMAL1 accumulated in distal tubular cytoplasm in both melatonin-treated groups. These findings suggest that melatonin mitigates obesity-induced renal pathology through anti-fibrotic inflammation-related mechanisms, while also revealing a novel link between circadian disruption and kidney injury. Our results support melatonin as a therapeutic agent for obesity-related renal disease. Full article

(This article belongs to the Special Issue Melatonin in Normal Physiology and Disease, 2nd Edition)

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13 pages, 1368 KB

Open AccessArticle

Feasibility Study on Inflammasome Proteins as Biomarkers in the Cerebrospinal Fluid of Pediatric Patients with Hydrocephalus Due to Intraventricular Hemorrhage

by MaryLourdes Andreu, Alexandra Castellanos, Robert W. Keane, Juan Pablo de Rivero Vaccari, Jennifer C. Muñoz Pareja, Helen M. Bramlett, W. Dalton Dietrich, Nadine A. Kerr and Heather J. McCrea

Biomolecules 2026, 16(1), 35; https://doi.org/10.3390/biom16010035 (registering DOI) - 25 Dec 2025

Abstract

Pediatric hydrocephalus results from the overproduction, obstruction, or inability to resorb cerebrospinal fluid (CSF), which may lead to ventricular enlargement. Hydrocephalus may be secondary to other pathologies, including intraventricular hemorrhage (IVH). Surgical intervention may include a ventricular access device or a ventriculosubgaleal shunt [...] Read more.

Pediatric hydrocephalus results from the overproduction, obstruction, or inability to resorb cerebrospinal fluid (CSF), which may lead to ventricular enlargement. Hydrocephalus may be secondary to other pathologies, including intraventricular hemorrhage (IVH). Surgical intervention may include a ventricular access device or a ventriculosubgaleal shunt in premature infants who are too small for permanent CSF diversion. Hydrocephalus, an inflammatory pathology, involves activation of the inflammasome. Elevation in pro-inflammatory proteins is often associated with worsening clinical outcomes in pediatric pathologies. Whether inflammasome proteins are reliable biomarkers for pediatric hydrocephalus has not been established. We analyzed CSF samples via an ELLA assay from pediatric hydrocephalic patients with IVH of prematurity vs. controls and compared changes in inflammasome protein concentrations post-reservoir surgery at different time points. The area under the curve was calculated using receiver operator characteristic curves. The levels of apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), caspase-1, and interleukin-18 were significantly elevated in pediatric hydrocephalic patients with IVH vs. controls. Thus, these proteins are reliable biomarkers of the inflammatory response in pediatric hydrocephalus following ROC analysis, with an AUC of 1.0 and high sensitivity and specificity at the corresponding cut-off points. Ongoing work seeks to validate these findings in a larger cohort of pediatric hydrocephalic patients with varying etiologies. Full article

(This article belongs to the Section Molecular Biomarkers)

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3 pages, 1003 KB

Open AccessCorrection

Correction: Onoiu et al. Circulating Lipid Profiles Indicate Incomplete Metabolic Recovery After Weight Loss, Suggesting the Need for Additional Interventions in Severe Obesity. Biomolecules 2025, 15, 1112

by Alina-Iuliana Onoiu, Vicente Cambra-Cortés, Andrea Jiménez-Franco, Anna Hernández-Aguilera, David Parada, Francesc Riu, Antonio Zorzano, Jordi Camps and Jorge Joven

Biomolecules 2026, 16(1), 34; https://doi.org/10.3390/biom16010034 (registering DOI) - 25 Dec 2025

Abstract

In the original publication [...] Full article

(This article belongs to the Section Molecular Biomarkers)

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21 pages, 3986 KB

Open AccessArticle

Heterogeneous Folding Intermediates Govern the Conformational Pathway of the RNA Recognition Motif Domain of the Ewing Sarcoma Protein

by Priyanka Kataria, Vishakha Chaudhary, Chandra Bhushan Mishra, Vijay Kumar, Ravi Datta Sharma and Amresh Prakash

Biomolecules 2026, 16(1), 33; https://doi.org/10.3390/biom16010033 (registering DOI) - 24 Dec 2025

Abstract

The RNA Recognition Motif (RRM) domain of the Ewing sarcoma (EWS) protein plays a pivotal role in RNA binding and gene regulation, being crucial for its function. However, its structural dynamics are yet to be revealed. Herein, we performed 5.5 μs cumulative molecular [...] Read more.

The RNA Recognition Motif (RRM) domain of the Ewing sarcoma (EWS) protein plays a pivotal role in RNA binding and gene regulation, being crucial for its function. However, its structural dynamics are yet to be revealed. Herein, we performed 5.5 μs cumulative molecular dynamics (MD) simulations to investigate the unfolding pathways of the EWS-RRM domain in urea and DMSO across 300–500 K. The unfolding process was characterized by using free-energy landscape (FEL) analysis, hydrogen-bond occupancy, and Gaussian Mixture Model (GMM) clustering. At lower temperatures (300–350 K), the RRM largely retained its native conformation, while extensive unfolding occurred between 400 and 450 K. Results revealed multiple conformational ensembles: native (N), native-like intermediate (I_N), intermediate (I), and unfolded (U) states, underlying the unfolding pathway of RRM. In urea at 400 K, a long-lived I-state dominated, with transient N and I_N-populations, whereas in DMSO, the I_N-state appeared more stable, that transitioned into tightly packed I-states, reflecting a stepwise unfolding via compact intermediates. At 450 K, the protein reached the U-state in both solvents, though unfolding occurred more readily in urea. This study highlights the solvent-dependent unfolding mechanisms and heterogeneous I-states of EWS-RRM, providing insight into its stability, misfolding, and potential relevance to Ewing sarcoma pathogenesis. Full article

(This article belongs to the Section Molecular Biophysics: Structure, Dynamics, and Function)

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24 pages, 1554 KB

Open AccessReview

NFS1 Plays a Critical Role in Regulating Ferroptosis Homeostasis

by Siying Sun, Hanwen Cao, Xuemei Li and Hongfei Liao

Biomolecules 2026, 16(1), 32; https://doi.org/10.3390/biom16010032 - 24 Dec 2025

Abstract

Ferroptosis is an iron-dependent form of regulated cell death (RCD) characterized by intracellular iron homeostasis disruption and lipid peroxide accumulation. It is involved in many pathological processes, including malignant tumors, cardiovascular diseases, inflammatory diseases, and mitochondrial disorders. Cysteine desulfurase (NFS1), a key enzyme [...] Read more.

Ferroptosis is an iron-dependent form of regulated cell death (RCD) characterized by intracellular iron homeostasis disruption and lipid peroxide accumulation. It is involved in many pathological processes, including malignant tumors, cardiovascular diseases, inflammatory diseases, and mitochondrial disorders. Cysteine desulfurase (NFS1), a key enzyme in mitochondrial iron-sulfur (Fe-S) cluster biosynthesis, participates in regulating cellular ferroptosis by maintaining Fe-S cluster homeostasis and modulating the ACO1/IRP1 axis, the Xc⁻–glutathione (GSH)–glutathione peroxidase 4 (GPX4) axis, and the p53/STAT signaling pathway. When the function of NFS1 is abnormal, the intracellular free iron level is elevated, followed by reactive oxygen species (ROS) accumulation and lipid peroxidation. NFS1 expression exhibits significant variation across different tissues. Upregulation of NFS1 in tumors can enhance tumor cell resistance to ferroptosis; thus, it can promote tumor growth, drug resistance, and metastatic ability. Conversely, downregulation of NFS1 in cardiomyocytes and neurons exacerbates ferroptosis and causes functional impairment. Here, we systematically review recent advances in the molecular mechanisms of NFS1-mediated ferroptosis and its role in various disease models, intending to clarify key components in the upstream regulatory network of ferroptosis and explore the application value of NFS1 as a potential therapeutic target. The review shows that NFS1 plays an important role in cellular fate regulation, which has significant clinical application potential in the treatment of cancer and interventions for neurological and cardiovascular diseases. Therefore, it can provide a new theoretical basis and research direction for subsequent mechanism research and targeted therapeutic strategy development. Full article

(This article belongs to the Section Molecular Biology)

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21 pages, 860 KB

Open AccessArticle

Engineering Single-Chain Antibody Fragment (scFv) Variants Targeting A Disintegrin and Metalloproteinase-17 (ADAM-17)

by Masoud Kalantar, Elham Khorasani Buxton, Korey M. Reid, Donald Bleyl, David M. Leitner and Maryam Raeeszadeh-Sarmazdeh

Biomolecules 2026, 16(1), 31; https://doi.org/10.3390/biom16010031 - 24 Dec 2025

Abstract

Metalloproteinases (MPs) are zinc-dependent endopeptidases, including matrix metalloproteinases (MMPs) and a disintegrin and metalloproteinases (ADAMs), implicated in various diseases such as cancer, neurodegenerative disorders, and cardiovascular conditions. Among MPs, ADAM-17, also known as tumor necrosis factor-α (TNF-α)-converting enzyme (TACE), plays a crucial role [...] Read more.

Metalloproteinases (MPs) are zinc-dependent endopeptidases, including matrix metalloproteinases (MMPs) and a disintegrin and metalloproteinases (ADAMs), implicated in various diseases such as cancer, neurodegenerative disorders, and cardiovascular conditions. Among MPs, ADAM-17, also known as tumor necrosis factor-α (TNF-α)-converting enzyme (TACE), plays a crucial role in extracellular matrix remodeling and cytokine release. Dysregulation of ADAM-17 contributes to inflammatory diseases, cancer progression, and immune modulation. While small-molecule inhibitors have been limited by off-target effects and instability, antibody-based approaches offer a more selective strategy. Monoclonal antibodies show promise in blocking ADAM-17 activity, but there are concerns about toxicity due to the lack of selectivity. Enhancing the binding affinity and selectivity of single-chain antibodies requires unraveling the structural details that drive MP targeting. This study uses yeast surface display (YSD) and fluorescence-activated cell sorting (FACS) to engineer single-chain variable fragment (scFv) antibodies with optimized complementarity-determining region 3 of the heavy chain (CDR-H3) conformations. Next-generation sequencing (NGS) was used to identify key residues contributing to high-affinity ADAM-17 binding. These findings offer a framework for designing monoclonal antibodies against ADAM-17 and other MPs, paving the way for novel antibody-based designer scaffolds with applications in developing therapeutics. Full article

(This article belongs to the Special Issue Harnessing Protein Design and Engineering for Therapeutic Applications)

15 pages, 1638 KB

Open AccessReview

The RNA-Binding Protein KSRP Is a Negative Regulator of Innate Immunity

by Vanessa Bolduan, Andrea Pautz and Matthias Bros

Biomolecules 2026, 16(1), 30; https://doi.org/10.3390/biom16010030 - 24 Dec 2025

Abstract

KSRP (KH-type splicing regulatory protein) has emerged as a pivotal regulator of gene expression at multiple levels, acting as a transcription and splicing factor in the nucleus, and mediating AU-rich element (ARE)-dependent mRNA decay, translational silencing, and microRNA (miRNA) maturation in the cytoplasm. [...] Read more.

KSRP (KH-type splicing regulatory protein) has emerged as a pivotal regulator of gene expression at multiple levels, acting as a transcription and splicing factor in the nucleus, and mediating AU-rich element (ARE)-dependent mRNA decay, translational silencing, and microRNA (miRNA) maturation in the cytoplasm. We and others have shown that KSRP acts as a regulator of immune responses, e.g., by dampening the expression of proinflammatory cytokines such as TNF-α, IL-6, IL-8, but also of NOS2, and facilitating the maturation of regulatory miRNAs, including let-7a, miR-129, and miR-155. This review aims to present current knowledge on the regulation of KSRP activity as conferred by miRNAs, phosphorylation, ubiquitination, SUMOylation, and interactions with long non-coding RNAs to enable dynamic responses towards inflammatory stimuli, and the effects of KSRP on innate immune reactions. Here, KSRP acts as an inhibitor by attenuating RIG-I-mediated antiviral signaling, cytokine production, and phagocytosis. In vivo, KSRP deficiency reduced arthritis severity but heightened inflammatory responses in sepsis and enhanced pathogen clearance in invasive pulmonary aspergillosis. These findings position KSRP as a dual regulator that limits tissue damage while constraining antimicrobial immunity. As a perspective, modulation of KSRP activity by applying pharmacological inhibitors may provide strategies to either suppress hyperinflammation in autoimmunity and sepsis or enhance host defense in immunocompromised states. Full article

(This article belongs to the Special Issue Feature Papers in Molecular Biology Section 2025)

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24 pages, 3174 KB

Open AccessArticle

Synthesis and Bioactivity Assessment of Novel Quinolinone–Triazole Hybrids

by Ioanna Kostopoulou, Maria-Anna Karadendrou, Manolis Matzapetakis, Maria Zervou, Georgia-Eirini Deligiannidou, Christos Kontogiorgis, Eleni Pontiki, Dimitra Hadjipavlou-Litina and Anastasia Detsi

Biomolecules 2026, 16(1), 29; https://doi.org/10.3390/biom16010029 - 24 Dec 2025

Abstract

Click chemistry, and particularly the Cu-catalyzed Azide Alkyne Cycloaddition (CuAAC) reaction has gained increased attention in recent years as an invaluable tool for synthesizing pharmaceutical active organic compounds. In this study, quinolinones and triazoles, two bioactive heterocyclic moieties amenable to various substitutions, were [...] Read more.

Click chemistry, and particularly the Cu-catalyzed Azide Alkyne Cycloaddition (CuAAC) reaction has gained increased attention in recent years as an invaluable tool for synthesizing pharmaceutical active organic compounds. In this study, quinolinones and triazoles, two bioactive heterocyclic moieties amenable to various substitutions, were employed to design and synthesize novel quinolinone–triazole hybrid molecules via the CuAAC click reaction under microwave irradiation. The synthesized hybrid molecules and their alkyne precursors were structurally characterized and evaluated for their antioxidant capacity, lipoxygenase (LOX) inhibitory activity, cell viability using HaCaT epithelial cells, and cytotoxicity against two cancer lines. The results indicated that, among the precursors, alkyne 4c exhibits the best combined antioxidant and anti-inflammatory activity (100% lipid peroxidation inhibition, IC₅₀ = 22.5 μM for LOX inhibition); among the hybrid molecules, compound 5a was the most potent (98.0% lipid peroxidation inhibition, IC₅₀ = 10.0 μM for LOX inhibition). Regarding the assessment of HaCaT cell viability, all studied compounds showed encouraging results, with cell viability rates between 61.5% and 100%. Moreover, based on the results of the cytotoxicity against cancer lines A549 and A375, it emerged that the tested compounds exhibited moderate–low or no cytotoxicity. These results highlight the potential of quinolinone–triazole hybrids as valuable candidates in drug discovery. Full article

(This article belongs to the Special Issue Heterocyclic Compounds: Synthesis, Characterization, and Validation)

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25 pages, 3920 KB

Open AccessArticle

Effect of the Icelandic Mutation APP^A673T in the Murine APP Gene on Phenotype of Line 66 Tau Mice

by Anne Anschuetz, Lianne Robinson, Miguel Mondesir, Valeria Melis, Bettina Platt, Charles R. Harrington, Gernot Riedel and Karima Schwab

Biomolecules 2026, 16(1), 28; https://doi.org/10.3390/biom16010028 - 24 Dec 2025

Abstract

The Icelandic mutation in the amyloid precursor protein (APP), APP^A673T, has been identified in Icelandic and Scandinavian populations and is associated with a significantly lower risk of developing Alzheimer’s disease (AD). The introduction of the human APP^A673T form led to [...] Read more.

The Icelandic mutation in the amyloid precursor protein (APP), APP^A673T, has been identified in Icelandic and Scandinavian populations and is associated with a significantly lower risk of developing Alzheimer’s disease (AD). The introduction of the human APP^A673T form led to a reduction in amyloid β-protein (Aβ) production and tau pathology, but the effect of mouse APP^A673T on tau and Aβ pathology is not well studied. We have crossed line 66 (L66) tau transgenic mice that overexpress the P301S aggregation-prone form of tau with C57Bl6/J mice expressing a single-point mutation edited into the murine APP gene via CRISPR-Cas gene editing, known as mAPP^A673T. We have performed ELISA, histopathological, and behavioural analyses of heterozygous male/female L66 and L66 xmAPP^A673T crosses at the age of 6 months to investigate the effect of the murine A673T mutation on tau brain pathology and behavioural deficits in these mice. Using immunohistochemistry, we found only a moderate, yet significant, reduction in mAb 7/51-reactive tau for female L66 x mAPP^A673T compared to L66 mice. Quantification of tau in soluble/insoluble brain homogenate fractions by ELISA confirmed the lack of overt differences between genotypes, as did our extensive behavioural phenotyping using six different paradigms assessing motor function, olfaction, depression/apathy-like behaviour, as well as exploration and sociability. Therefore, the mAPP^A673T mutation has a moderate impact on tau pathology but does not appear to impact motor and neuropsychiatric behaviour in L66 tau transgenic mice. Full article

(This article belongs to the Section Biomacromolecules: Proteins, Nucleic Acids and Carbohydrates)

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35 pages, 1000 KB

Open AccessReview

From Mechanism to Medicine: Peptide-Based Approaches for Cancer Diagnosis and Therapy

by Maria João Gouveia, Joana Campanhã, Francisca Barbosa and Nuno Vale

Biomolecules 2026, 16(1), 27; https://doi.org/10.3390/biom16010027 - 24 Dec 2025

Abstract

Therapeutic peptides have rapidly evolved into multifunctional tools for precision oncology, offering molecular specificity and biocompatibility. Their roles in cancer therapy, however, are inherently overlapping. The same peptide can function as a targeting ligand, a cell-penetrating motif, a therapeutic effector, or a structural [...] Read more.

Therapeutic peptides have rapidly evolved into multifunctional tools for precision oncology, offering molecular specificity and biocompatibility. Their roles in cancer therapy, however, are inherently overlapping. The same peptide can function as a targeting ligand, a cell-penetrating motif, a therapeutic effector, or a structural component of peptide–drug conjugates (PDCs), nanoparticle (NP) systems, and radionuclide constructs. This functional convergence makes rigid classification challenging. In this review, we therefore organize peptide modalities according to their dominant therapeutic function while acknowledging the fluid boundaries between categories. Firstly, we outline the main functional classes of therapeutic peptides, covering their use as targeting ligands and their roles as active agents (i.e., receptor agonists/antagonists, intracellular protein–protein interaction modulators, etc.). Additionally, we summarize their application in peptide–drug conjugates (PDCs), peptide-guided radionuclides, and cancer vaccines, integrating key mechanistic principles and clinical evidence. Finally, we discuss the major translational barriers to clinical use and how they might be overcome. The developments in peptide engineering position them as adaptable, multifunctional platforms capable of improving precision, reducing toxicity, and advancing personalized cancer care. Full article

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28 pages, 4216 KB

Open AccessReview

Oral–Gut Microbial Crosstalk and Therapeutic Applications of Bacterial Extracellular Vesicles

by Wenmei Fu, Ninghan Yang, Jiale Yan, Bing Han, Qin Niu, Zhengyu Li, Rushui Bai and Tingting Yu

Biomolecules 2026, 16(1), 26; https://doi.org/10.3390/biom16010026 - 24 Dec 2025

Abstract

With the accelerating trend of global population aging, oral and gut diseases are imposing a rising socioeconomic burden, both of which have well-known connections to microbial dysbiosis. As the gateway to the human body, the oral cavity exhibits close interactions with the gastrointestinal [...] Read more.

With the accelerating trend of global population aging, oral and gut diseases are imposing a rising socioeconomic burden, both of which have well-known connections to microbial dysbiosis. As the gateway to the human body, the oral cavity exhibits close interactions with the gastrointestinal tract, which includes translocation of bacteria and bacterial extracellular vesicles (BEVs), as well as intermucosal immunity and neural signaling. These oral–gut crosstalk pathways play vital roles in the pathogenesis and progression of oral diseases, such as periodontitis, and gut diseases, such as inflammatory bowel disease (IBD). Focusing on periodontitis and IBD as representative conditions, this review summarizes current understanding of the oral–gut crosstalk and underlying mechanisms. Among diverse interactions, we emphasize BEVs as effective trans-barrier mediators and their therapeutic potentials during oral–gut crosstalk. Beneficial BEVs, notably those from Akkermansia muciniphila (Akk), exert various probiotic roles, including modulating microbial homeostasis, promoting tissue repair and alleviating inflammation, thereby shedding light on the prevention and treatment of oral and gut diseases, even systemic disorders. Full article

(This article belongs to the Section Molecular Medicine)

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29 pages, 4286 KB

Open AccessReview

Mechanistic Insights into the Metabolic Pathways and Neuroprotective Potential of Pentacyclic Triterpenoids: In-Depth Analysis of Betulin, Betulinic, and Ursolic Acids

by Mihai Adrian Socaciu, Zorita Diaconeasa, Dumitrita Rugina, Carmen Socaciu, Remus Moldovan and Simona Clichici

Biomolecules 2026, 16(1), 25; https://doi.org/10.3390/biom16010025 - 24 Dec 2025

Abstract

Due to their complexity, both genotypic and phenotypic, neurodegenerative diseases are one of the main causes of death globally nowadays. Among phytochemicals of high scientific interest, based on experimental studies, pentacyclic triterpenoids (TTs), including mainly betulin, betulinic, and ursolic acid, became targets of [...] Read more.

Due to their complexity, both genotypic and phenotypic, neurodegenerative diseases are one of the main causes of death globally nowadays. Among phytochemicals of high scientific interest, based on experimental studies, pentacyclic triterpenoids (TTs), including mainly betulin, betulinic, and ursolic acid, became targets of scientific research in recent years, especially in terms of their biological activity and pharmacological potential. Due to their anti-inflammatory and antioxidant properties, as well as their involvement in cellular signal transductions, they have been observed to act as anticancer, chemopreventive, and neuroprotective agents. The aim of this review is to update the reader on the diversity, bioavailability, pharmacological properties, and neuroprotective effects of TTs, as biomolecules that can interfere with metabolic mechanisms related to neurodegeneration and restoring of neuronal integrity. Recent data were analyzed, with a particular focus on mechanistic insights related to their neuroprotective effects. Starting with their biosynthetic pathways, bioavailability, and involvement in specific metabolic pathways, their impact on neurological pathology and benefits as natural neuroprotection agents through specific signaling pathways are presented. Furthermore, emphasis will also be put on current challenges and future strategies that could develop TTs into effective compounds for neuroprotection and personalized medicine. Full article

(This article belongs to the Special Issue Advances in Metabolomics in Health and Disease)

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19 pages, 2951 KB

Open AccessReview

Dimerized Power: The Antimicrobial and Antiviral Promise of Biflavonoids

by Hatice Duman, Sercan Karav, Anita Šalić and Dunja Šamec

Biomolecules 2026, 16(1), 24; https://doi.org/10.3390/biom16010024 - 23 Dec 2025

Abstract

Biflavonoids, a unique class of naturally occurring polyphenolic compounds formed by the dimerization of flavonoid units, have attracted increasing scientific interest due to their diverse biological activities and structural complexity. This review provides a comprehensive overview of their natural occurrence, synthetic strategies, and [...] Read more.

Biflavonoids, a unique class of naturally occurring polyphenolic compounds formed by the dimerization of flavonoid units, have attracted increasing scientific interest due to their diverse biological activities and structural complexity. This review provides a comprehensive overview of their natural occurrence, synthetic strategies, and antimicrobial properties, with a particular focus on their antibacterial, antifungal, and antiviral activities. Comparative analyses indicate that biflavonoids often display enhanced or distinct biological effects compared to their monomeric flavonoid counterparts, suggesting that dimerization plays a crucial role in modulating bioactivity. Overall, biflavonoids represent an underexplored yet highly promising group of natural compounds with significant potential for the development of novel antimicrobial and antiviral agents. Continued interdisciplinary research integrating natural product chemistry, pharmacology, and computational modeling will be essential to fully realize their therapeutic potential. Full article

(This article belongs to the Special Issue The Value of Natural Compounds as Therapeutic Agents: 3rd Edition)

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30 pages, 1996 KB

Open AccessReview

Electrochemical Choline Sensing: Biological Context, Electron Transfer Pathways and Practical Design Strategies

by Angel A. J. Torriero, Sarah M. Thiak and Ashwin K. V. Mruthunjaya

Biomolecules 2026, 16(1), 23; https://doi.org/10.3390/biom16010023 - 23 Dec 2025

Abstract

Choline is a central metabolite that connects membrane turnover, neurotransmission, and one-carbon metabolism, and its reliable measurement across diverse biological matrices remains a significant analytical challenge. This review brings together biological context, electrochemical mechanisms, and device engineering to define realistic performance targets for [...] Read more.

Choline is a central metabolite that connects membrane turnover, neurotransmission, and one-carbon metabolism, and its reliable measurement across diverse biological matrices remains a significant analytical challenge. This review brings together biological context, electrochemical mechanisms, and device engineering to define realistic performance targets for choline sensors in blood, cerebrospinal fluid, extracellular space, and milk. We examine enzymatic sensor architectures ranging from peroxide-based detection to mediated electron transfer via ferrocene derivatives, quinones, and osmium redox polymers and assess how applied potential, oxygen availability, and film structure shape electron-transfer pathways. Evidence for direct electron transfer with choline oxidase is critically evaluated, with emphasis on the essential controls needed to distinguish true flavin-based communication from peroxide-related artefacts. We also examine bienzymatic formats that allow operation at low or negative bias and discuss strategies for matrix-matched validation, selectivity, drift control, and resistance to fouling. To support reliable translation, we outline reporting standards that include matrix-specific concentration ranges, reference electrode notation, mediator characteristics, selectivity panels, and access to raw electrochemical traces. By connecting biological requirements to mechanistic pathways and practical design considerations, this review provides a coherent framework for developing choline sensors that deliver stable, reproducible performance in real samples. Full article

(This article belongs to the Section Chemical Biology)

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37 pages, 928 KB

Open AccessReview

The Xenopus Oocyte System: Molecular Dynamics of Maturation, Fertilization, and Post-Ovulatory Fate

by Ken-Ichi Sato

Biomolecules 2026, 16(1), 22; https://doi.org/10.3390/biom16010022 - 23 Dec 2025

Abstract

The Xenopus oocyte has long served as a versatile and powerful model for dissecting the molecular underpinnings of reproductive and developmental processes. Its large size, manipulability, and well-characterized cell cycle states have enabled generations of researchers to illuminate key aspects of oocyte maturation, [...] Read more.

The Xenopus oocyte has long served as a versatile and powerful model for dissecting the molecular underpinnings of reproductive and developmental processes. Its large size, manipulability, and well-characterized cell cycle states have enabled generations of researchers to illuminate key aspects of oocyte maturation, fertilization, and early embryogenesis. This review provides an integrated overview of the cellular and molecular events that define the Xenopus oocyte’s transition from meiotic arrest to embryonic activation—or alternatively, to programmed demise if fertilization fails. We begin by exploring the architectural and biochemical landscape of the oocyte, including polarity, cytoskeletal organization, and nuclear dynamics. The regulatory networks governing meiotic resumption are then examined, with a focus on MPF (Cdk1/Cyclin B), MAPK cascades, and translational control via CPEB-mediated cytoplasmic polyadenylation. Fertilization is highlighted as a calcium-dependent trigger for oocyte activation. During fertilization in vertebrates, sperm-delivered phospholipase C zeta (PLCζ) is a key activator of Ca²⁺ signaling in mammals. In contrast, amphibian species such as Xenopus lack a PLCZ1 ortholog and instead appear to rely on alternative protease-mediated signaling mechanisms, including the uroplakin III–Src tyrosine kinase pathway and matrix metalloproteinase (MMP)-2 activity, to achieve egg activation. The review also addresses the molecular fate of unfertilized eggs, comparing apoptotic and necrotic mechanisms and their relevance to reproductive health. Finally, we discuss recent innovations in Xenopus-based technologies such as mRNA microinjection, genome editing, and in vitro ovulation systems, which are opening new avenues in developmental biology and translational medicine. By integrating classic findings with emerging frontiers, this review underscores the continued value of the Xenopus model in elucidating the fundamental processes of life’s origin. We conclude with perspectives on unresolved questions and future directions in oocyte and early embryonic research. Full article

(This article belongs to the Special Issue Gametogenesis and Gamete Interaction, 2nd Edition)

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