Search Results (825)

The γδ T cells belong to a subgroup of T cells known as non-conventional T cells due to their limited T cell receptor (TCR) repertoire and ability to recognize non-peptide antigens. They play a crucial role in combating infections and tumors. Vγ9Vδ2 T cells are typically activated by molecules containing diphosphate groups, collectively known as phosphoantigens (pAgs), through a non-canonical mechanism which involves the intracellular domain of butyrofilin (BTN)3A1 protein. However, no FDA-approved drugs have yet been shown to activate them, and the underlying cellular mechanisms remain unknown. In this study, we combined high-throughput virtual screening of an FDA-approved drug database with in vitro cellular assays to identify potential γδ T cells activators. Our findings demonstrate that Nitazoxanide (NTZ) and Tinidazole induce moderate elicited a statistically significant increase in interferon (IFN)-γ production of Vγ9Vδ2 T cells by their probably interaction with the pAg binding site of BTN3A1. Additionally, NTZ induces expression of CD107a, but only at the highest concentrations tested and promotes the upregulation of HLA-DR in total PBMCs and CD14⁺ monocytes. Blocking BTN3A with a specific antibody led to a marked reduction in all NTZ-induced activations. This work identifies NTZ as a previously unrecognized activator of γδ T cells, highlighting its immunomodulatory potential beyond its known clinical uses. These findings broaden our understanding of γδ T cells pharmacology and suggest new opportunities for drug repurposing and the design of novel chemical scaffolds. Further mechanistic studies will be essential to fully define how NTZ engages the BTN3A–γδ T cells axis. Full article

Bispecific peptides represent an emerging therapeutic platform in immunotherapy, offering simultaneous engagement of two distinct molecular targets to enhance specificity, functional synergy, and immune modulation. Their compact structure and modular design enable precise interaction with protein–protein interfaces and shallow binding sites that are otherwise difficult to target. This review summarizes current design strategies of bispecific peptides, including fused, linked, and self-assembled architectures, and elucidates their mechanisms in bridging tumor cells with immune effector cells and blocking immune checkpoint pathways. Recent developments highlight their potential applications not only in oncology but also in autoimmune and infectious diseases. Key translational challenges, including proteolytic stability, immunogenicity, delivery barriers, and manufacturing scalability, are discussed, along with emerging peptide engineering and computational design strategies to address these limitations. Bispecific peptides offer a versatile and adaptable platform poised to advance precision immunotherapy and expand therapeutic options across immune-mediated diseases. Full article

Background/Objectives: Monoclonal antibody (mAb) stability is critical not only during manufacturing but also at the point of clinical administration. For therapies like tislelizumab (Tevimbra), a programmed death-1 (PD-1) targeting IgG mAb, delays in dosing often result in prepared infusions being discarded, contributing to substantial drug waste despite being engineered for improved stability. Methods: To evaluate the physicochemical in-use stability of tislelizumab in a ready-to-administer format, we mapped degradation pathways, including post-translational modifications (PTMs); peptide alterations; pH and solution characteristics—under 12-month storage (ultra-long), under 1-month storage (0, 7, 14, 21, 28 and 31 days), and under exposure-related forced degradation conditions including room temperature, elevated temperature, pH (acidic/basic), oxidation and UV exposure. Structural analysis was contextualised to the known PD-1 binding site, making stability assessment relevant to tislelizumab’s mechanism-of-action in blocking PD-1. To assess solution stability, a validated size-exclusion chromatography (SEC) assay was applied to all conditions. Results: Aggregation was identified as the primary degradation pathway during ultra-long-term storage. SEC and chemical assessment revealed no measurable changes in protein quantity, aggregation, peptide integrity, or PTM profile over 31 days at 2–8 °C in polyolefin intravenous bags (1.6 mg/mL). Conclusions: These results support the structural and physicochemical stability of tislelizumab under refrigerated conditions. Full article

Animal toxins contain various bioactive peptides and proteins which have evolved to interact in specific ways. As such, they are a good starting point for developing new drugs and vaccines. This paper examines three natural neurotoxins derived from the black mamba (Dendroaspis polylepis), which show significant pharmacological potential: mambalgins, fasciculins and dendrotoxins. All three may be of value in the treatment of pain, cancer and neurodegenerative disease. Mambalgins provide similar pain relief to opioids but without the risk of addiction; they act by selectively blocking acid-sensitive ion channels (ASICs), especially ASIC1a. Thanks to this inhibitory activity they also demonstrate selective activity against glioblastoma, melanoma and leukemia cells as innovative anticancer drugs. Fasciculins are very strong inhibitors of acetylcholinesterase (AChE) and hence offer promise in multi-target drugs and as treatments for treating Alzheimer’s disease. Dendrotoxins such as DTX-K and DTX-I are able to modulate neuronal excitability and synaptic transmission by blocking voltage-gated potassium channels (Kv1.1, Kv1.2, Kv1.6); both have been shown to be effective against cancer cells, and to influence the cardiovascular, immune, and digestive systems. Recent advances in recombinant biotechnology and protein engineering have allowed their safe production with increased therapeutic value. The review examines the translational potential of D. polylepis venom proteins and highlights the need for additional preclinical research on bioactive molecules of toxin origin. Full article

Antiviral peptides (AVPs) are promising therapeutic candidates, yet the rapid growth of sequence data and the field’s emphasis on predictors have left a gap: the lack of an integrated view linking peptide chemistry with biological context. Here, we map the AVP landscape through interactive data mining using Half-Space Proximal Networks (HSPNs) and Metadata Networks (MNs) in the StarPep toolbox. HSPNs minimize edges and avoid fixed thresholds, reducing computational cost while enabling high-resolution analysis. A threshold-free HSPN resolved eight chemically and biologically distinct communities, while MNs contextualized AVPs by source, function, and target, revealing structural–functional relationships. To capture diversity compactly, we applied centrality-guided scaffold extraction with redundancy removal (90–50% identity), producing four representative subsets suitable for modeling and similarity searches. Alignment-free motif discovery yielded 33 validated motifs, including 10 overlapping with reported AVP signatures and 23 apparently novel. Motifs displayed category-specific enrichment across antimicrobial classes, and sequences carrying multiple motifs (≥4–5) consistently showed higher predicted antiviral probabilities. Beyond computational insights, scaffolds provide representative “entry points” into AVP chemical space, while motifs serve as modular building blocks for rational design. Together, these resources provide an integrated framework that may inform AVP discovery and support scaffold- and motif-guided therapeutic design. Full article

In this work, a novel solid polymer electrolyte with a disordered structure has been designed, combining polyethylene glycol (PEG) as the flexible segments and hexamethylene diisocyanate (HDI) as the rigid segments. The synthesis was realized by alternating flexible PEG with rigid HDI through a peptide bond (–CO–NH–), which disrupts the ordered structures of PEG, generating electron-deficient Lewis acid groups. The pathbreaking introduction of HDI blocks not only bridges links between the PEG molecules but also generates electron-deficient Lewis acid groups. Therefore, the original ordered structures of PEG are disrupted by both the alternating chains between PEG and HDI and the Lewis acid groups. As a result, the PEG_H/L4000 electrolytes (PEG molecular weight of 4000) exhibit a strong anion-capture ability that decreases the crystallinity of polymers, which further achieves a high ionic conductivity close to 10⁻³ S·cm⁻¹ with the lithium-ion transference numbers up to 0.88. The symmetric Li|PEG_H/L4000|Li cells maintain a low and stable voltage polarization for more than 800 h at 0.1 mA·cm⁻². Furthermore, the LiFePO₄|PEG_H/L4000|Li all-solid-state cells perform well both in cycling and rate performances. The design of polymer disordered structures for polymer electrolytes provides a new thought for manufacturing all-solid-state lithium-ion batteries with high safety as well as long life. Full article

Since the first paper published by Susan Cole in 1990 detailing multidrug resistance mediated by ABCC1/MRP1, research into the C-subfamily of ATP-binding cassette transporters has continued to uncover a wide range of functionally divergent proteins. However, several orphan transporters remain in the C-subfamily, and the physiological function and substrates of ABCC5, ABCC11, and ABCC12 remain elusive. This review explores the emerging understanding of human ABCC5. Unlike other ABC transporters with well-defined drug export functions, ABCC5’s physiological roles remain only partially understood. While it is known for its involvement in multidrug resistance in cancers, recent studies suggest broader implications in development, metabolism, neurobiology, and male fertility. ABCC5 exports various endogenous substrates, including cyclic nucleotides (cAMP and cGMP), glutamate conjugates like NAAG, and possibly haem. Knockout models in mice, zebrafish, and sea urchins reveal ABCC5’s role in gut formation, brain function, eye development, and iron metabolism. In mice, its deletion results in lower adipose tissue mass, enhanced insulin sensitivity, and neurobehavioral changes resembling schizophrenia, highlighting its role in glutamatergic signalling and circadian regulation. Functionally, ABCC5 appears to impact adipocyte differentiation and GLP-1 release, implicating it in type 2 diabetes susceptibility in humans. Structural studies using human ABCC5 revealed a novel autoinhibitory mechanism involving a peptide segment (C46–S64) that blocks substrate binding, offering new potential for selective inhibitor development. However, this review emphasises caution in targeting ABCC5 for cancer therapy due to its underappreciated physiological function(s), particularly in the brain and male reproductive system. Understanding ABCC5’s substrate specificity, regulatory mechanisms, and functional redundancy with its paralog ABCC12 remains critical for successful therapeutic strategies in humans. Full article

Lipopolysaccharide (LPS), an essential structural molecule in the outer membrane of Gram-negative bacteria, is recognized as a principal trigger of inflammatory responses and oxidative stress. Thus, the control and clearance of LPS is essential to inhibit LPS-induced excessive inflammation, oxidative stress, and liver injury. In recent years, some native bioactive peptides, such as human β-defensin 126 (DEFB126) and thymopentin (TP5), have been reported to have inhibitory effects against LPS-induced inflammation and oxidative stress. However, the cytotoxicity, weak stability, and poor biological activity have hindered their practical application and clinical development. The development of novel hybrid peptides is a promising approach for overcoming these problems. In this study, we designed a novel hybrid peptide [DTP, DEFB126 (1-39)-TP5] that combines the active center of DEFB126 and full-length thymopentin (TP5). Compared to the parental peptides, DTP has a longer half-life, lower cytotoxicity, and greater anti-inflammatory and antioxidant activity. The anti-inflammatory and antioxidant effects of DTP were demonstrated in a murine LPS-induced sepsis model, which showed that DTP successfully inhibited the indicators associated with LPS-induced liver injury; decreased the contents of TNF-α, IL-6, and IL-1β; increased the level of glutathione (GSH); and improved the activities of catalase (CAT) and superoxide dismutase (SOD). Furthermore, our study revealed that the anti-inflammatory and antioxidant activities of DTP were associated with LPS neutralization, blockade of LPS binding to the Toll-like receptor 4/myeloid differentiation factor 2 (TLR4/MD-2) complex, reduction in reactive oxygen species content, and inhibition of the activation of the nuclear factor kappa-B (NF-кB) signaling pathway. These results elucidate the structural and functional properties of the peptide DTP, reveal its underlying molecular mechanisms, and shed light on its potential as a multifunctional agent for applications in agriculture, food technology, and clinical therapeutics. Full article

Breast cancer (BC) is a major cause of cancer-related mortality. Mortalin and Vimentin—two proteins implicated in BC progression and metastasis—have been identified as binding partners of the Secretion Modification Region (SMR) peptide from the HIV Nef protein. These interactions disrupt exosome release and offer novel therapeutic strategies. This study investigates the binding interactions between the SMR peptide, Mortalin, and Vimentin using surface plasmon resonance (SPR), co-immunoprecipitation (Co-IP), and Western blot assays. We also map the SMR binding sites on Mortalin through scanning peptide mapping and then identify a similar site on the Vimentin protein. Based on these data, we propose that the SMR peptide and its analogs interact with specific amino acid sequences in Mortalin and Vimentin, thereby disrupting cellular processes essential for Epithelial–Mesenchymal Transition (EMT) and tumor progression. SPR analysis revealed that the Nef protein exhibited the highest binding affinity to Vimentin (KD = 0.75 ± 1.1 nM) and Mortalin (KD = 3.16 ± 0.03 nM). The SMRwt peptide also demonstrated direct binding to both proteins with micromolar affinities (KD = 6.63 ± 0.74 µM for Vimentin; KD = 20.73 ± 2.33 µM for Mortalin), though the binding affinity was weaker than the full Nef protein. Co-IP experiments using MDA-MB-231, MCF-7, and BT474 BC cell lines confirmed that SMRwt, but not SMRmut, co-immunoprecipitated with Mortalin. Western blot analysis validated these interactions. Further, Mortalin peptide #56, derived from the substrate-binding domain, did not bind the SMR domain or inhibit Nef function. In contrast, peptides #61 and #62 from the C-terminal domain of Mortalin bound the SMR domain and effectively inhibited Nef activity. Notably, Mortalin peptide #61 inhibited SMRwt binding to both Mortalin and Vimentin, disrupting complex formation on the SPR sensor chip. These findings suggest that specific Mortalin-derived peptides can block SMR interactions, offering a potential therapeutic mechanism. Full article

Sugar amino acids (SAAs) represent a privileged class of molecular chimeras that uniquely merge the structural rigidity of carbohydrates with the functional display of amino acids. These hybrid molecules have garnered significant attention as programmable conformational constraints, offering a powerful strategy to overcome the inherent limitations of peptide-based therapeutics, such as proteolytic instability and conformational ambiguity. The strategic incorporation of SAAs into peptide backbones, particularly within cyclic frameworks, allows for the rational design of peptidomimetics with pre-organized secondary structures, enhanced metabolic stability, and improved physicochemical properties. This review provides a comprehensive analysis of the synthetic methodologies developed to access the diverse structural landscape of SAAs, with a focus on modern, stereoselective strategies that yield versatile building blocks for peptide chemistry. A critical examination of the structural impact of SAA incorporation reveals their profound ability to induce and stabilize specific secondary structures, such as β- and γ-turns. Furthermore, a comparative analysis positions SAAs in the context of other widely used peptidomimetic scaffolds, highlighting their unique advantages in combining conformational control with tunable hydrophilicity. We surveyed the application of SAA-containing cyclic peptides as therapeutic agents, with a detailed case study on gramicidin S analogs that underscores the power of SAAs in elucidating complex structure–activity relationships. Finally, this review presents a forward-looking perspective on the challenges and future directions of the field, emphasizing the transformative potential of computational design, artificial intelligence, and advanced bioconjugation techniques to accelerate the development of next-generation SAA-based therapeutics. Full article

Candida species commonly secrete aspartic peptidases (Saps), which are virulence factors involved in nutrient acquisition, colonization, tissue invasion, immune evasion and host adaptation. However, the regulation of Sap production remains poorly characterized in emerging, widespread and multidrug-resistant members of the Candida haemulonii clade (C. auris, C. haemulonii, C. haemulonii var. vulnera and C. duobushaemulonii). This study investigated the influence of temperature, pH and protein substrate on Sap production using bloodstream isolates of the C. haemulonii clade. Sap activity was initially assessed using the enzyme coefficient (Pz) in fungal cells grown on yeast carbon base (YCB) agar supplemented with bovine serum albumin (BSA) to determine optimal conditions for enzymatic production. C. auris and C. duobushaemulonii exhibited the highest Sap activity at 96 h, pH 4.0–5.0, and 37 °C, whereas C. haemulonii and C. haemulonii var. vulnera displayed more variable and isolate-dependent profiles. Sap production was markedly suppressed at pH 6.0. The addition of pepstatin A, an inhibitor of aspartic peptidases, abolished Sap activity and impaired fungal growth in a dose-dependent manner, confirming both the enzymatic identity and its critical role in nitrogen acquisition. Conversely, YCB supplemented with an inorganic nitrogen source (ammonium sulfate) supported fungal growth but did not induce Sap production. To explore substrate specificity, YCB was supplemented with a panel of proteins. Serum albumins (bovine and human) induced the highest Sap production, followed by globulin, gelatin, hemoglobin, collagen and immunoglobulin G, while elastin and mucin elicited the lowest Sap production. Isolate-specific preferences for protein substrates were observed. Finally, fluorometric assays using a Sap-specific fluorogenic peptide substrate confirmed the presence of Sap activity in cell-free supernatants, which was consistently and entirely blocked by pepstatin A. These findings highlight inter- and intraspecies variability in Sap regulation among C. haemulonii clade, stressing the critical roles of substrate availability, pH and temperature in shaping fungal adaptation to host environments. Full article

Heterotetramerization of Kv1.1 and Kv1.2 α-subunits expands the functional diversity of voltage-gated potassium Kv1 channels in the central nervous system (CNS), thus necessitating the study of the properties of these heterochannels, including their interactions with ligands. We report on the expression, electrophysiological, and ligand-binding properties of human heterochannels Kv(1.1-1.2)₂ formed by dimeric concatemers Kv1.1-Kv1.2 fused with fluorescent protein mKate2 in Neuro-2a cells. Kv(1.1-1.2)₂ is a low-voltage-activated, highly active, non-inactivating channel with a fast activation rate. Its activation rate and half-maximum activation voltage are similar to that of the Kv1.1 channel, but differ from that of Kv1.2. This suggests that the membrane expression of Kv(1.1-1.2)₂ may functionally compensate for the absence of membrane presentation of homotetrameric Kv1.1 channels in CNS. Hongotoxin 1 fused with fluorescent protein GFP (HgTx-G) is shown to be a pore-blocking ligand of Kv(1.1-1.2)₂ with a dissociation constant of 100 pM. Using confocal microscopy and competitive binding assay, HgTx-G and cells expressing Kv(1.1-1.2)₂, the apparent dissociation constants of the complexes between Kv(1.1-1.2)₂ and peptides Ce1, Ce4, hongotoxin 1, MeKTx11-1, agitoxin 2, charybdotoxin, and scyllatoxin were evaluated to be 14, 33, 40, 250, 800, and >>3300 pM, respectively. Heterotetramerization of α-subunits has a different effect on the affinity of ligands compared to those for Kv1.1 and Kv1.2 channels. Full article

The corticotropin-releasing factor (CRF) and its type 1 receptor (CRF₁R) play a key role in the regulation of the hypothalamic–pituitary–adrenal (HPA) axis. Dysregulation of the HPA axis is associated with congenital adrenal hyperplasia (CAH) and depression. Non-peptide CRF₁R-selective antagonists displayed antidepressant effects on animal models and are used for the management of CAH. To develop novel non-peptide CRF₁R antagonists, we have previously designed and synthesized a series of substituted pyrimidines. Among these analogs, molecule 43 (M43) binds to CRF₁R with the highest affinity. Based on this finding, we selected M43 for further pharmacological characterization in the present study. The results suggest that M43 is a potent CRF₁R antagonist, blocking the ability of the CRF-related agonist, Tyr⁰-sauvagine, to stimulate (1) cAMP accumulation in HEK 293 cells expressing CRF₁R and (2) the proliferation rate of RAW 264.7 macrophages. Computational studies suggest that the antagonist properties of M43 are mostly attributed to its ability to interact with residues in the allosteric pocket of CRF₁R, comprised of the third, fifth, and sixth transmembrane domain residues, which block activation-associated structural rearrangements of the receptor. Our data will be used to design novel non-peptide CRF₁R antagonists for clinical use. Full article

Self-assembled nanoparticles formed with amphiphilic block or graft copolymers are being extensively studied for their use in a variety of biological and industrial applications, including targeted drug delivery. This study reports a novel strategy to tune the structure of self-assembled nanoparticles for enhancing the cellular uptake by varying the hydrophilic ratio of amphiphilic graft copolymers. We synthesized poly(aspartic acid) (PAsp) substituted with octadecyl chains (C18) at varying degrees of substitution (DS), ranging from 4.5 to 37.5 mol%, which could form self-assemblies in an aqueous solution. As the DS increased, a morphological transition was observed—from spherical assemblies (DS 4.5 and 9.1) to rod-like (DS 19.0), vesicular (DS 25.7), and lamellar-like structures (DS 37.6). Further, Trans-Activator of Transcription (TAT) as the cell penetrating peptide to the synthesized amphiphilic graft copolymers leads to an enhanced cellular uptake of the biomimetic self-assembly. In particular, the lamellar-like self-assemblies resulted in a 1.3-fold increase of cellular uptake, as compared to the spherical self-assemblies, and a 3.6-fold increase, as compared to the vesicles. Therefore, tuning the structure of poly(aspartic acid)s’ self-assemblies was proven as an effective strategy to enhance the cellular uptake, while minimizing invasive cell damage. This new strategy to tune the morphologies of self-assemblies will serve to improve the cell penetrating activity for targeted drug delivery. Full article

Background: Acute SARS-CoV-2 infection may induce cardiac arrhythmias associated with viral myocarditis, which typically disappear in the convalescent phase after healing of the myocardial inflammation. Methods: We report the case of a 37-year-old woman with a childhood history of atrial septal defect repair and stable normofrequent atrial rhythm, who presented two months post-COVID-19 with palpitations and dizziness. Diagnostic evaluation included cardiac magnetic resonance imaging (CMR), 24 h Holter electrocardiogram (ECG) monitoring, and laboratory assessments over a 3-year period. Results: CMR suggested subacute myocarditis, and Holter ECG revealed multiple discernible complex cardiac arrhythmias including atrial bradycardia, intermittent junctional rhythm (JR), atrial fibrillation (AF), and non-sustained ventricular tachycardia. Laboratory results showed a moderate but transient increase in lactate dehydrogenase, persistently mildly elevated N-terminal pro–B-type natriuretic peptide (NT-proBNP), and immunoglobulin A (IgA), with all other cardiac, inflammatory, immunologic, and organ function parameters remaining normal. In spite of chaotic cardiac rhythm with alternating JR, AF, and atrial normofrequent rhythm with frequent blocked supraventricular beats and increasing atrioventricular conduction time, no therapeutic intervention was necessary during follow-up, and a conservative treatment approach was agreed with the patient. Two years post-COVID-19 infection, the patient returned to a normofrequent atrial rhythm with a markedly prolonged PQ time (500 ms) and a different P wave morphology compared to pre-COVID, without other rhythm disturbances. Conclusions: This case demonstrates a rare pattern of post-viral arrhythmias first emerging in the convalescent phase and resolving spontaneously after two years. It underscores the need for long-term rhythm surveillance following COVID-19, even in patients with prior structural heart disease and a stable baseline rhythm. Full article