Search Results (1,887)

Differentiation therapy holds significant potential for the treatment of multiple myeloma (MM). We previously identified that the aminopeptidase N (APN) inhibitor Bestatin promotes MM cell differentiation. Herein, we elucidate the underlying molecular mechanisms of this process. Utilizing MM1.S, U266, and RPMI-8226 cell lines, a combination of CCK-8 assays, flow cytometry, Wright–Giemsa staining, Western blotting, qRT-PCR, ELISA, APN enzymatic activity analysis, SA-β-gal staining, and bioinformatic analyses revealed elevated APN expression across all cell types. Bestatin treatment induced MM cell differentiation in a concentration-dependent manner, which was accompanied by the upregulation of the differentiation marker CD49e, increased immunoglobulin light chain secretion, elevated cellular senescence, and a concomitant suppression of cell proliferation and APN enzymatic activity. Mechanistically, Bestatin exerts its effects by downregulating the CD79B/BTK signaling pathway, thereby activating the downstream transcription factor STAT3. Consistent with this axis, direct inhibition of CD79B/BTK alone was sufficient to induce differentiation, while blockade of STAT3 completely abrogated the differentiation-promoting effect of Bestatin. The APN-neutralizing antibody (WM15) yielded consistent results with Bestatin, further validating this regulatory axis. Furthermore, both the CD79B/BTK inhibitor Ibrutinib and the STAT3 agonist GCDA potentiated the cytotoxicity of the clinical MM drug Ixazomib. Bestatin itself synergized with Ixazomib and enhanced the anti-proliferative effect of IL-6. In summary, our findings establish that the APN inhibitor Bestatin induces MM cell differentiation via the CD79B/BTK-STAT3 signaling axis. Targeting this pathway represents a promising strategy to enhance the efficacy of Ixazomib, providing a compelling rationale for novel combination therapies in MM. Full article

Gammaherpesviruses are oncogenic viruses that reprogram host cell metabolism to support viral production. Among these, murine herpesvirus 68 (MHV-68) serves as a model system for studying lytic gammaherpesvirus infection and associated host cell changes. To characterize host transcriptional alterations induced throughout lytic gammaherpesvirus infection and identify novel host pathways that may be therapeutically targeted, we performed temporal bulk RNA-sequencing of mock- and MHV-68-infected NIH 3T3 cells at various timepoints throughout the lytic cycle. Our analysis revealed widespread and progressive host gene expression changes, including robust innate immune pathways and extensive remodeling of metabolic gene expression. We further identified a strong activation of the pentose phosphate pathway (PPP) genes, accompanied by increased abundance in PPP metabolic intermediates. Pharmacological inhibition of the PPP with 6-aminonicotinamide (6-AN) reduced infectious virus production. Moreover, at the intersection of metabolic and transcriptional reprogramming, we identified infection-associated gene expression changes in chromatin-modulating enzymes, including Tet2, and their metabolite co-factors, such as α-KG. Pharmacological inhibition of Ten-Eleven Translocation (TET) enzymatic activity led to a marked decrease in infectious MHV-68 production. Collectively, these findings define a novel metabolic–epigenetic crosstalk that supports productive gammaherpesvirus replication and identifies host pathways that can be targeted to treat lytic gammaherpesvirus infections. Full article

Phosphodiesterase-1 (PDE1) represents an attractive target for the treatment of idiopathic pulmonary fibrosis (IPF). However, the limited chemical diversity of current PDE1 inhibitors has hindered the development of potential anti-IPF drugs, primarily due to an ambiguous understanding of interactions between inhibitors and PDE1. Herein, we report an integrated virtual screening strategy containing pharmacophore modeling, molecular docking, and molecular dynamics simulations, which markedly accelerated the discovery of novel PDE1 inhibitors. Enzymatic assays identified eleven active compounds with moderate inhibition from twenty-six purchased candidates, encompassing nine distinct scaffold types. Notably, 6484-0008 and 6484-0032 exhibited more than 50% inhibition at a concentration of 1 μM. Hydrogen bond analysis and residue-based energy decompositions revealed key recognition mechanisms involving crucial residues Gln421, His373, and Phe424, as well as the unique Thr271 in the flexible H-loop region, providing insights for the rational design of inhibitors with enhanced potency. Full article

Background/Objectives:α-Mangostin, a natural product from Garcinia mangostana L, presents very strong antibacterial activity in plant flavonoids against Staphylococcus aureus. Recently, it was reported that the quinone pool is a key target of α-mangostin against Gram-positive bacteria. Here, the detail centering this action mechanism of α-mangostin killing S. aureus was further explored. Methods: The interactions between α-mangostin and type II NADH:quinone oxidoreductase (NDH-2), a key enzyme in the respiratory chain, were explored through the enzyme kinetic experiments, fluorescence analyses, and molecular simulation. Simultaneously, the effect of α-mangostin on membrane potential was also investigated as a possible non-enzymatic mechanism. Results: it was found that α-mangostin mainly competes the menaquinone-binding sites of NDH-2 with menaquinone, and the half-maximal inhibitory concentration (IC₅₀) of α-mangostin on NDH-2 is 4.95 μM. Fluorescence analyses indicated that α-mangostin can spontaneously bind to NDH-2 to form an α-mangostin–NDH-2 complex. Subsequently, molecular simulation further showed that α-mangostin can dock to the menaquinone-binding sites of NDH-2. In addition, non-enzymatic mechanism showed that α-mangostin can cause membrane potential depolarization and disrupt the proton motive force balance, thereby promoting the cell-membrane destruction of S. aureus. Conclusions: α-Mangostin can mainly interact with the amino acid residues at the menaquinone-binding pocket of NDH-2 to block the electron transfer at the quinone pool in the respiratory chain of S. aureus, which will hinder the energy supply and act synergistically with cell membrane damage, ultimately leading to the death of S. aureus. Simultaneously, it once again proves that the quinone pool is a key target of plant flavonoids against Gram-positive bacteria. Full article

Goat blood, a major slaughterhouse by-product, was systematically valorized into dual-function bioactive peptides through an optimized four-step process. Four blood preparations—whole blood (HB), anticoagulant-treated blood (HBS), red blood corpuscles (BC), and plasma (PM)—were subjected to heat pretreatment (90 °C, 15 min) and enzymatic hydrolysis. Neutrase hydrolysis of heat-pretreated whole blood at 8% substrate concentration for 4 h (HBN-8) yielded optimal protein recovery (44.38%) with dual ACE (88.24%) and DPP-IV (81.13%) inhibition. Ultrafiltration enriched bioactive peptides in the ≤3 kDa fraction (DPP-IV: 87.8%; ACE: 65.5%). LC-MS/MS de novo sequencing identified 14 novel peptide sequences (4–9 amino acids), with the most potent SEC fraction showing IC₅₀ values of 0.89 and 0.45 mg Leu eq./mL for DPP-IV and ACE inhibition, respectively. Critically, simulated gastrointestinal digestion enhanced rather than diminished bioactivity, with ACE inhibition increasing progressively to 60.91% at the intestinal phase, supported by predicted generation of bioactive fragments from parent sequences. Caco-2 assays confirmed peptide safety (100–1000 µg/mL) and demonstrated 10.47% transepithelial transport with retained dual inhibitory activities. This study establishes goat blood as a sustainable source of orally bioavailable, GI-stable peptides for the development of functional foods targeting hypertension and type 2 diabetes. Full article

Protein lactylation, an emerging post-translational modification (PTM) driven by the metabolite lactate, has surfaced as an important regulatory layer contributing to the crosstalk between metabolic reprogramming and cellular functional plasticity in colorectal cancer (CRC). Within the unique “host–microbiota” symbiotic microenvironment of CRC, the Warburg effect—fueled jointly by oncogene activation and microbial metabolism—provides abundant substrates for lactylation. This modification is dynamically regulated by a complex enzymatic system comprising “Writers” (e.g., p300/CREB-binding protein [p300/CBP], alanyl-tRNA synthetase 1/2 [AARS1/2]) and “Erasers” (e.g., histone deacetylases [HDACs] and Sirtuins). Through intricate crosstalk with other PTMs, such as acetylation and ubiquitination, lactylation exerts critical regulatory effects on both the histone epigenetic landscape and non-histone protein functions. Functionally, lactylation not only drives malignant proliferation, invasion, and metastasis but also systematically remodels the immunosuppressive “cold” tumor microenvironment. Furthermore, it confers broad-spectrum resistance to chemotherapy, radiotherapy, targeted therapy, and immunotherapy by orchestrating a ferroptosis defense network, enhancing DNA damage repair (DDR), and activating protective autophagy. This review systematically synthesizes the regulatory networks and biological functions of lactylation in CRC, deeply elucidating the core mechanisms underlying therapy resistance. Finally, we discuss the clinical translational potential of lactylation as a novel diagnostic/prognostic biomarker and therapeutic target, aiming to provide new theoretical foundations and strategic directions for overcoming current bottlenecks in CRC clinical treatment. Full article

Plastic pollution caused by poly(ethylene terephthalate) (PET) highlights the urgent need for efficient biodegradation strategies. However, PET hydrolases such as DuraPETase typically exhibit limited substrate affinity for PET and insufficient operational stability. Although conventional immobilization improves enzyme stability, it often compromises catalytic activity. Here, we design a PET-targeting, orientation-controlled immobilization strategy that overcomes this traditional trade-off and enables efficient PET biodegradation. Guided by rational structural analysis, three Cys variants (R53C, R59C, R224C) were engineered for site-specific covalent attachment to a PDA@SiO₂ support with inherent PET-binding capability. The resulting conjugates (Dura_R53C-PDA@SiO₂, Dura_R59C-PDA@SiO₂, and Dura_R224C-PDA@SiO₂) displayed distinct catalytic and stability profiles. Among them, Dura_R59C-PDA@SiO₂ achieved the optimal balance between activity and stability, retaining kinetic properties comparable to the free enzyme and maintaining 87.6% residual activity after 2 h at 80 °C. Water contact angle measurements confirmed its PET-targeting behavior, as evidenced by the reduction in the PET contact angle from 85° to 45°. In 10-day degradation assays at 50 °C, Dura_R59C-PDA@SiO₂ released a total of 4865.32 μM degradation products, representing a 2.37-fold increase relative to free DuraPETase. These findings demonstrate an effective strategy for industrial enzymatic PET degradation and recycling. Full article

Traditional pharmacotherapy is often constrained by suboptimal bioavailability and systemic toxicity. Biomolecularly inspired nano-drug delivery systems (nano-DDS) have emerged as precise platforms to overcome these barriers by orchestrating molecular interactions at the bio-nano interface. This review systematically evaluates the molecular recognition mechanisms and biochemical principles governing nano-DDS performance. We systematically evaluate how passive targeting relies on the EPR effect—dictated by the nanocarrier’s physicochemical properties—and how active targeting exploits ligand-receptor affinity to enhance cellular uptake. Special emphasis is placed on bioresponsive strategies that utilize pathological cues—such as pH gradients, redox potential, and enzymatic activity—for intelligent, on-demand drug release. Furthermore, we discuss structure-function relationships in lipid, polymeric, and biologically derived systems, highlighting their roles in modulating therapeutic signaling in oncology and inflammatory diseases. Finally, translational hurdles and emerging AI-driven molecular design strategies are critically examined. Full article

Ubiquitination is a key post-translational modification regulating cellular signaling and innate immunity, and its reversal by deubiquitinases (DUBs) represents a critical mechanism exploited by pathogens for immune evasion. While ovarian tumor (OTU) domain-containing DUBs are well characterized in viral systems, their roles in fungal pathogens remain largely unexplored. In this study, we investigated two putative OTU domain-containing proteins derived from the plant pathogenic fungi Melampsora larici-populina (MlpOTU, EGG09943.1) and Taphrina deformans (TdOTU, CCG84064.1). Recombinant MlpOTU and TdOTU proteins were successfully expressed and purified from E. coli and exhibited high solubility and proper folding. Functional analyses in HEK293T cells demonstrated that both proteins significantly reduce global ubiquitination levels, confirming their deubiquitinase activity in vivo. Despite this shared enzymatic function, the two proteins displayed markedly distinct effects on host immune gene expression. MlpOTU selectively suppressed key antiviral effectors, most notably MX1, suggesting a targeted immune evasion strategy. In contrast, TdOTU induced robust upregulation of multiple immune-related genes, including type I interferons, indicating a divergent role. Neither MlpOTU nor TdOTU triggered robust apoptosis, supporting their role as modulators of host signaling rather than cytotoxic effectors. Collectively, these findings provide the first functional evidence that fungal OTU domain-containing proteins act as active deubiquitinases and reveal distinct strategies by which plant pathogens may manipulate host immune responses. This study establishes fungal OTU domains as promising targets for antifungal intervention and broadens our understanding of cross-kingdom evasion mechanisms. Full article

Aminoglycoside resistance is commonly mediated by enzymatic modification, target alteration, or efflux mechanisms; however, acquired resistance has not been characterized in radiation-resistant Deinococcus species. Here, we investigated the occurrence and genomic context of acquired aminoglycoside resistance genes in all publicly available Deinococcus radiodurans genomes. A total of 19 genomes were screened using ResFinder and CARD, followed by comparative genomic analyses. The aadA1 gene was identified in two genomes, being located on the plasmid pSP1 in strain R1 dM1, a known shuttle vector used for genetic manipulation. In contrast, aadA1 was found on a chromosomal contig in strain DRR11, suggesting a possible assembly artifact. Additionally, the aph(3′)-Ia gene was detected in three genomes within a conserved chromosomal region that lacks this gene in reference strains. Sequence similarity analyses indicated that aph(3′)-Ia is associated with laboratory vectors, being consistent with a potential non-natural origin. Considering the high recombination capacity and genomic plasticity of D. radiodurans, these findings suggest that the detected aminoglycoside resistance genes may be derived from laboratory constructs, potentially combined with assembly inconsistencies or chromosomal integration events. Therefore, this study highlights the importance of integrating genomic context with molecular and evolutionary plausibility to avoid misinterpretation of antimicrobial resistance in extremophiles and model organisms, and underscores the importance of complementary raw-read analyses to distinguish natural acquisition from technical or laboratory-derived origins. Full article

Background: Cancer cells exhibit metabolic reprogramming characterized by increased dependence on glutamine to sustain rapid proliferation and biosynthetic demands. Kidney-type glutaminase (KGA), which catalyzes the first and rate-limiting step of glutamine metabolism, represents a promising therapeutic target, particularly in triple-negative breast cancer (TNBC), an aggressive sub-type lacking effective targeted therapies. This study evaluated 2-amino-4-boronobutyric acid (ABBA), a boronic acid-containing glutamine analog, as a potential KGA inhibitor with anticancer activity. Methods: KGA inhibition was assessed using a fluorometric enzymatic assay. Cytotoxic effects were examined in multiple TNBC cell lines. Covalent docking and molecular simulation analysis were performed to characterize interactions between ABBA and the KGA active site. Results: ABBA potently inhibited KGA activity, with an IC₅₀ of approximately 1.0 μM, demonstrating greater efficacy than several non-proteinogenic amino acid analogs. ABBA induced dose-dependent cytotoxicity across multiple TNBC cell lines, with pronounced sensitivity observed in basal sub-type cells and cellular sensitivity correlated with KGA expression levels. Expression of γ-glutamyl transpeptidase 1 (GGT1) was negligible, and, excluding any off-target effects, the observed anticancer effects are primarily attributed to KGA inhibition. Docking analysis indicated that ABBA forms a reversible covalent adduct with the catalytic Ser286 residue of KGA in a boronate tetrahedral geometry resembling transition-state mimics, while molecular simulation demonstrated stabilization of the complex through hydrogen bonding and electrostatic interactions. Conclusions: ABBA is a potent boron-based glutaminase inhibitor with therapeutic potential for targeting glutamine metabolism in TNBC. Further structural optimization and in vivo evaluation are warranted to advance ABBA toward therapeutic development. Full article

Multiple sclerosis (MS) is a chronic, progressive, inflammatory neurodegenerative disease. Oxidative stress and ferroptosis are implicated in MS pathology, contributing to both inflammation and neurodegeneration. Potentially functional variants in genes related to antioxidant defense and ferroptosis were chosen through an extensive selection process to investigate their possible association with the progressive form of MS. The study included 845 MS patients (604 relapsing–remitting (RRMS) and 241 progressive (PMS)). The selected gene variants—GCLC rs572496, GCLM rs2273406, GPX4 rs713041, NQO1 rs1800566 and CAT rs2420388—were genotyped using TaqMan^® technology. mRNA expression levels of the corresponding genes in PBMCs were previously determined by targeted RNA sequencing. Circulatory molecular indicators of antioxidant defense and ferroptosis were quantified using ELISA and colorimetric enzymatic recycling assays. The findings indicate that the GCLC rs572496 variant was significantly associated with MS disease severity and had a significant effect on GCLC mRNA levels. Additionally, the NQO1 rs1800566 variant had a significant effect on NQO1 mRNA expression in PBMCs of MS patients overall. The results suggest further analysis of antioxidant defense and ferroptosis-related gene variants with MS severity and validation of the gained results in larger study groups. Full article

Sirtuin 1 (SIRT1) is an important protein for maintaining cellular homeostasis, and targeting SIRT1 represents a promising strategy for alleviating osteoporosis. The discovery of highly potent and safe SIRT1 activators therefore holds significant translational value for clinical anti-osteoporosis therapies. In this study, we performed deep mining of high-throughput RNA-sequencing (RNA-seq) data from 576 young and aged skeletal stem/progenitor cells (SSPCs) and identified SIRT1 downregulation as a critical hallmark of SSPC ferroptosis during aging-related osteoporosis. In SIRT1 heterozygous deficiency (SIRT1^+/−) mice, we found that SIRT1 deficiency triggered SSPC ferroptosis and induced premature osteoporosis. Computer-aided drug design (CADD) was employed to screen 9634 compounds targeting the SIRT1 active site, leading to the identification of the natural compound Hydroxygenkwanin (HGK) as a novel SIRT1 activator. HGK treatment effectively restored SIRT1 activity, suppressed ferroptosis in SSPCs in vitro, and ameliorated osteoporosis in vivo. Through transcriptomic analysis and lactylation profiling, we further found that HGK can activate SIRT1 and reverse the lactylation-mediated suppression of the enzymatic activities of SOD1 and PRDX1. This mechanism may underlie the ability of HGK to reduce SSPC ferroptosis and alleviate osteoporosis. Overall, our findings suggest that HGK possesses translational potential for the treatment of osteoporosis through SIRT1 activation. Full article

This review examines sorghum digestibility from molecular structure to clinical implications, focusing on compositional factors, processing methods, and health outcomes. We evaluate how sorghum’s unique protein–starch interactions influence digestibility and explore emerging technologies that can modulate these properties for targeted nutritional benefits. Cooked sorghum generally has lower digestibility than raw sorghum and other cereals due to heat-induced protein–starch cross-linking and the formation of disulfide bonds by sorghum proteins (kafirins), which restrict enzymatic access. Enzyme inhibitors in sorghum further reduce starch hydrolysis. This reduced digestibility may negatively impact malnourished individuals and those relying on sorghum as a dietary staple. However, it can be advantageous to individuals with diabetes by lowering postprandial blood glucose levels. Sorghum consumption may also beneficially influence the gut microbiome. Certain processing methods have been shown to significantly enhance digestibility while preserving beneficial bioactive compounds. Improving digestibility through these strategies may enhance sorghum’s value for vulnerable populations while maintaining its metabolic advantages. Balancing increased nutrient bioavailability with preservation of beneficial functional properties is critical for optimizing sorghum as a health-promoting grain across diverse populations. Full article

Plant–pathogen interactions are shaped by dynamic regulatory processes that control immune signaling. Among these, post-translational modifications (PTMs) play central roles in modulating protein activity, stability, and interaction networks. Increasing evidence indicates that Phytophthora effectors target PTM-dependent regulatory systems to suppress host immunity and promote infection. Here, we synthesize current knowledge on how Phytophthora virulence factors manipulate post-translational regulation through two mechanistically distinct strategies: (i) canonical mechanisms, involving direct enzymatic modification of host proteins or the recruitment of host PTM-modifying enzymes, and (ii) non-canonical mechanisms, in which effectors alter the activity, organization, or localization of PTM-associated regulatory systems without directly inducing covalent modification. These processes frequently involve protein–protein interactions and oligomerization-dependent regulation that reshape signaling complexes and enzymatic accessibility. By distinguishing effector-mediated PTM induction from regulatory interference, we provide a mechanistic framework for interpreting how diverse virulence strategies converge on the control of immune signaling pathways, including those governing reactive oxygen species production, transcriptional regulation, hormone signaling, and cell death. We further highlight current limitations in mechanistic understanding and emphasize the need for integrative approaches combining structural biology and proteomics to resolve how effectors reprogram host signaling systems. Full article