Search Results (263)

Full-length ACTH molecule and ACTH-related hexapeptide H-PKKRRP-OH are demonstrated by the patch-clamp method to decrease the Na_V1.8 channel activation gating system effective charge in the nociceptive neuron membrane, while ACTH-related tetrapeptide Ac-KKRR-NH₂ has no effect. ACTH(1–24), a fully functional ACTH mimetic, and H-PKKRRP-OH show analgesic effects in the formalin test in vivo. All peptides contain the cationic KKRR motif, but only H-PKKRRP-OH and ACTH(1–24) relieve acute pain, targeting the Na_V1.8 channel as a receptor. This seemingly controversial result is explained by application of conformational analysis and blind docking. Though conformational analysis indicates that both H-PKKRRP-OH and Ac-KKRR-NH₂ contain the cationic functional groups at the earlier suggested characteristic distance of 9–12 Å, Ac-KKRR-NH₂ does not interact with the S4_I voltage sensor of the Na_V1.8 channel activation gating system. The docking demonstrates that an extensive network of ligand–receptor ionic and hydrogen bonds involving D151, E157, R218, and R221 VSD_I residues, essential for the analgesic tripeptide Ac-KKK-NH₂ binding, is formed upon the H-PKKRRP-OH binding. Particularly important are the ionic bonds between the H-PKKRRP-OH C-terminal carboxylate anion and the S4_I R218 and R221 guanidinium groups. The described mechanism of Na_V1.8 channel modulation is fundamentally different from the effect of channel blockers. Full article

Bovine mastitis caused by multidrug-resistant (MDR) Escherichia coli remains a major challenge in the dairy industry due to recurrent infection, excessive lipopolysaccharide (LPS) release, and persistent mammary inflammation. Whole-genome sequencing (WGS) revealed that the clinical isolate was resistant to seven classes of antibiotics and exhibited a marked enrichment of iron uptake systems, which accounted for 27.14% of the 140 virulence genes identified. Upon this, we developed a targeted combination therapy using the iron mimetic gallium nitrate and the antimicrobial peptide thanatin (Tn). A rat model of mastitis was established to evaluate the in vivo therapeutic efficacy of the Tn-gallium nitrate combination. Our results demonstrated that the combination of gallium nitrate and Tn exerted a potent enhanced therapeutic effect in the rat mastitis model. This regimen significantly inhibited bacterial proliferation, neutralized endotoxin activity, and downregulated the expression of pro-inflammatory cytokines. Histopathological evaluation confirmed that the combination therapy effectively protected the alveolar structure and alleviated tissue damage, with a protective effect superior to that of ceftiofur (CEF), the first-line clinical drug. Collectively, our findings demonstrate the therapeutic potential of the combination of thanatin and gallium nitrate in a rat model of mastitis and provide experimental evidence supporting the development of a novel non-antibiotic therapeutic strategy for bovine mastitis caused by multidrug-resistant E. coli. Full article

Protein–protein interactions (PPIs) represent a vast and largely underexplored landscape of therapeutic targets, yet their structural features—including large, flat, and dynamic interfaces—have historically limited their druggability. In this context, cyclic peptides have emerged as a powerful class of PPI modulators, sitting at the interface between biologics and small molecules, and thus garnering key advantages of both classes. Their conformational constraint enhances binding affinity, proteolytic stability and, in some instances, cell permeability, thus enabling access to intracellular targets. This review provides an updated overview of cyclic peptides as modulators of PPIs, focusing on both conceptual foundations and practical strategies for their discovery and optimization. The main discovery approaches include natural sources, de novo design based on secondary structure mimetics, high-throughput screening, and computational approaches. Integration of these complementary strategies is crucial to enhance success rates in the discovery of effective and developable cyclic peptides. Accordingly, the present review aims to provide a practical guide for researchers entering this rapidly growing field, outlining current opportunities, methodological advances, and remaining challenges in the development of cyclic peptide-based PPI modulators. Full article

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder characterized by cognitive decline, the deposition of amyloid-β (Aβ) plaques, the formation of neurofibrillary tangles, and cerebrovascular dysfunction. Evidence suggests that blood-borne lipoproteins play a role in the disease’s pathophysiology by influencing the cerebrovasculature and amyloid metabolism. Low-density lipoprotein (LDL) and very-low-density lipoprotein (VLDL) can contribute to oxidative stress, endothelial dysfunction, vascular dysfunction, and the accumulation of amyloidogenic peptides, thereby exacerbating neurodegeneration. The role of lipoprotein(a) (Lp(a)) remains unclear, whereas high-density lipoprotein (HDL) is recognized for its cerebroprotective properties, including anti-inflammatory and vasoreactive functions. These properties help to maintain neuronal homeostasis and facilitate the clearance of Aβ from the brain. This review summarizes the current evidence regarding the role of lipoproteins in AD and discusses how therapeutic strategies targeting lipoprotein pathways, such as lipid-lowering agents and HDL mimetics developed for cardiovascular diseases, may benefit patients with AD. Full article

Objectives: An ideal cardiotoxicity inhibitor targeting the angiotensin (Ang) II type 1 (AT₁) receptor would be a β-arrestin-biased orthostatic ligand, which inhibits the G protein pathway and activates the β-arrestin pathway. Therefore, this study examined seven Ang II mimetic peptides (MP1–7), Ang A and TRV027 as potential β-arrestin-biased AT₁ receptor ligands to prevent doxorubicin (Dox)-induced cardiotoxicity. Methods: Competition binding study, inositol phosphate (IP) production assay and extracellular signal-regulated kinase (ERK) 1/2 activation were performed using COS7 cells. Changes in phosphorylated Akt (Ser473), c-Jun N-terminal kinase (JNK) (Thr183/Tyr185), Bad (Ser112), Bcl-2 (Ser70), p53 (Ser46), active caspase-8 (Asp384) and active caspase-9 (Asp315) in cell lysates were measured using AT₁ receptor-transfected H9C2 cells. Results: Binding assays showed Ang II and Ang A had the highest affinity, with MP2 and MP7 similar to TRV027. IP production was strong for Ang II and Ang A, minimal for MP1 and MP7, and no stimulation for MP2 and TRV027. Ang II and Ang A significantly activated ERK1/2 in this cell system. MP2 and MP7 in addition to TRV027 also significantly activated ERK1/2, whereas MP1 did not activate it. Dox-activated JNK and Bad, while Ang A, TRV027, MP2, and MP7 inhibited JNK activation without affecting Bad or Akt. Conclusions: MP2, which is a candidate biased ligand for the AT₁ receptor and has similar amino acid sequence to TRV027, along with TRV027, attenuated Dox-induced JNK activation while avoiding excessive G protein-mediated activation. Interestingly, MP7, which showed minimal G protein-mediated activation with β-arrestin-mediated ERK activation, also attenuated Dox-induced JNK activation, a marker of pro-apoptotic stress signaling. Full article

Hydrogel scaffolds have emerged as instructive microenvironments for craniofacial tissue regeneration, moving beyond passive cell carriers toward platforms that regulate cell fate, vascularization, immune remodeling, and tissue-specific architecture. This review synthesizes hydrogel-associated strategies across dental pulp, periodontal ligament, gingival, bone marrow, jawbone, endothelial, oral mucosal, induced pluripotent stem cell (iPSC), extracellular vesicle (EV), exosome, secretome, and acellular systems. The evidence indicates that craniofacial hydrogel performance is governed by reciprocal interactions among biological source, scaffold composition, matrix mechanics, spatial architecture, mineral or ionic signaling, growth factor delivery, vesicle-mediated communication, and inflammatory niche modulation. Mineralized and ion-releasing hydrogels most consistently supported osteogenesis and bone repair, whereas extracellular matrix (ECM)-mimetic, peptide, collagen, fibrin, gelatin methacryloyl (GelMA), alginate, hyaluronic acid (HA), and chitosan-based systems enabled pulp–dentin, periodontal, peri-implant, oral mucosal, and soft-tissue reconstruction. Responsive, antimicrobial, antioxidant, conductive, and immunomodulatory hydrogels further expanded the field by targeting diseased microenvironments rather than regeneration alone. Despite strong preclinical evidence, translation remains limited by heterogeneity in scaffold formulations, biological sources, analytical endpoints, defect models, and long-term functional validation. Future progress will require standardized characterization, tissue-specific design criteria, clinically relevant large-animal models, scalable cell-free technologies, and integrated assessment of regeneration, immunity, vascularization, innervation, mechanics, and safety. Full article

Anticontractile factors secreted by perivascular adipose tissue (PVAT) play an important role in regulating vascular tone. This process is driven by the neurotransmitter norepinephrine (NE), but recent data show that adrenergic innervation in PVAT is sparse. How limited innervation might initiate broad responses through PVAT depots remains unknown. Here, we used Ca²⁺ imaging with genetically encoded sensors, selective drugs, immunolabeling and a conditional ablation model to test the hypothesis that gap junction coupling among PVAT adipocytes contributes to how signals initiated by NE are distributed through PVAT depots. Despite exhibiting differing sensitivities to NE, adipocytes in aortic and mesenteric PVAT and in white adipose tissue displayed robust expression of the gap junction protein connexin-43 (Cx43). Blocking gap junction coupling with the drug carbenoxolone (Cbx) limited NE-evoked Ca²⁺ responses among adipocytes, while blocking Cx43 hemichannels with the mimetic peptide 43Gap26 had no significant effect. Fluorescence recovery after photobleaching (FRAP) in mPVAT was decreased in the presence of Cbx, suggesting impaired gap junction communication. Wire myography recordings of mesenteric arteries showed that the EC₅₀ for NE was higher in samples with intact PVAT than those without; however, this effect was not significantly different in samples from mice that lacked Cx43 in adipocytes. Analysis of multiple connexins showed that adipocytes upregulate Cx26 gene expression when Cx43 is deleted. These observations support the conclusion that Cx43-mediated gap junction coupling among PVAT adipocytes contributes to distributing signals initiated by NE; however, how this mechanism contributes to regulating vessel constriction remains unclear. This, and how potential compensatory mechanisms are enacted in adipocytes lacking Cx43, should be addressed in future work. Full article

Background: Depression and anxiety are prevalent mental health disorders that substantially impact quality of life. The association of incretin mimetics, including glucagon-like peptide-1 (GLP-1) receptor agonists, with symptoms of depression and anxiety remain underexplored in Saudi Arabia. This study was conducted to assess the association between GLP-1 receptor agonist use and symptoms of depression and anxiety and to identify related factors. Methods: A cross-sectional study using convenience sampling was conducted among adults (≥18 years) treated with GLP-1 receptor agonists at King Khalid University Hospital (KKUH) in Riyadh, Saudi Arabia. Data were collected using a questionnaire developed by the research team, in addition to the Arabic versions of the Patient Health Questionnaire-9 (PHQ-9) and the Generalized Anxiety Disorder-7 (GAD-7). Results: A total of 235 participants were included, of whom 48.5% used GLP-1 receptor agonists for both glycemic control and weight loss. Only 31.9% had undergone psychiatric evaluation prior to initiating therapy, and 14.9% had a diagnosed psychiatric disorder. The mean anxiety score (GAD-7) was 4.82 ± 5, and the mean depression score (PHQ-9) was 6.13 ± 4.95. Multivariable analysis showed that higher odds of more severe depression were associated with using diabetes medications for weight loss in addition to diabetes treatment, a history of psychiatric disorders, and holding a bachelor’s degree. Exercising for 101–150 min per week was associated with lower odds of depression. Regarding anxiety, participants who exercised 101–150 min per week had significantly lower odds of anxiety compared with those who did not exercise, while a history of psychiatric disorders was associated with higher odds of more severe anxiety. Conclusions: This study’s findings highlight the importance of integrating both routine psychiatric screening and follow-up into diabetes and obesity management to enhance both psychological well-being and metabolic outcomes. They also reflect the benefit of physical activity for mental health, emphasizing the need to encourage exercise among individuals with diabetes or obesity. Full article

Laccase plays an important role in the detection and degradation of phenolic compounds, but it is limited by its cost and stability. In this study, the laccase-like property of copper peptide (GHK-Cu) has been revealed. In terms of enzymatic reaction kinetics, GHK-Cu has a V_max of 1.735 × 10⁻⁴ mM·s⁻¹ and a K_m of 0.061 mM, demonstrating good substrate affinity and excellent catalytic efficiency. Then, a colorimetry was developed for rapid detection of epinephrine (EP) and 2-aminophenol (2-AP). The linear response range of EP is 20–240 μM, with a limit of detection (LOD) of 9.5 μM. The linear response ranges of 2-AP are 14–100 μM (in ultrapure water) and 2–120 μM (in seawater), with LODs of 2.56 μM and 1.65 μM. In addition, combined with a smartphone platform, a cotton-based sensor has been developed for the detection of 2-AP in seawater. The linear response ranges are 0–0.2 mM and 0.2–1 mM, with LOD of 0.033 mM. The structure of GHK-Cu provides a reference for the development of novel laccase mimetic enzymes. The constructed colorimetry offers an option for the rapid detection of phenolic compounds, and the developed cotton-based sensor enabled rapid and portable detection of 2-AP. Full article

Rotator cuff tendon injury (RCTI) is aggravated by the pro-inflammatory milieu elicited by TLR4 and TREM1 signaling. Hence, tendon tissue engineering approaches require considerations that address these inflammatory episodes to benefit active regenerative responses. The objective of this study was to engineer and evaluate the immunocompatibility of a tendon-mimetic hydrogel composed of a chitosan–polyvinyl alcohol (PVA) blend incorporated with Collagen-I and to assess LR12 delivery for addressing TREM1-driven inflammation in RCTI management. A chitosan–PVA-HEMA-Acrylic acid (CPHA) hydrogel was synthesized by blending the linear natural polysaccharide chitosan and linear synthetic polymer PVA in an aqueous phase, followed by incorporation and redox chain growth with HEMA using acrylic acid (AA). Interpenetration of Collagen-I in CPHA yielded the CPHA-C hydrogel. CPHA and CPHA-C hydrogels displayed ample surface functional moieties provided by the co-polymers, exhibited excellent porosity as revealed by SEM imaging (28.65 ± 6.85 and 41.56 ± 18.00, respectively, for CPHA and CPHA-C), and were amphiphilic, as evident by contact angle analysis (~70 for CPHA and CPHA-C). Both hydrogels displayed a progressive release profile for the TREM1-inhibitory peptide LR12 for 7 days, whereas the LR12-loaded CPHA hydrogel exhibited increased TREM1 inhibition in LPS-challenged RAW264.7 macrophages. CPHA and CPHA-C hydrogels were immunocompatible and masked the oxidative damage in RAW264.7 macrophages, as evident by decreased levels of mitochondrial superoxide and ROS. Additionally, the CPHA hydrogel displayed an increased TGFβ/TLR4 ratio (0.24), whereas the CPHA-C (−0.52) system showed a decreased ratio upon exposure to tenocytes and macrophages. Overall, the findings highlight the potential of CPHA and CPHA-C hydrogels as candidates for tendon regenerative applications. Full article

Diabetic nephropathy (DN) is the leading cause of end-stage renal disease worldwide. During the last few years, remarkable advances have been made in the treatment of DN. Sodium–glucose cotransporter type 2 inhibitors (SGLT2i) consistently prevent or delay albuminuria and renal failure in patients with DN. Prior research from our group highlights the Janus kinase/signal transducers and activators of transcription axis as a critical target in DN. Specifically, the administration of suppression of cytokine signaling 1 (SOCS1) mimetic peptides (MiS1) modulates aberrant signaling, resulting in profound beneficial effects on renal function and structural integrity in experimental DN. The aim of this study was to evaluate the effect of empagliflozin and MiS1 on kidney damage and its associated inflammatory, oxidative stress and lipotoxic mechanisms in an advanced type 2 DN mouse model BTBR ob/ob. Mice were treated for 7 weeks with empagliflozin and MiS1, alone or in combination, and monitored for glycemia, body weight, albuminuria, histopathological damage, podocyte loss, and gene expression related to inflammation, redox balance, and lipid metabolism. Empagliflozin or MiS1 monotherapies significantly reduced albuminuria and structural renal injury, preserved podocyte number, and downregulated genes involved in inflammatory, oxidative, and mitochondrial–lipid metabolic dysregulation, with empagliflozin additionally improving metabolic parameters. Notably, the combined therapy achieved the greatest reduction in albuminuria and histological damage with enhanced suppression of pathogenic inflammatory and metabolic pathways, resulting in superior renoprotection compared with monotherapy. These findings suggested that add-on therapy with SOCS1 peptidomimetics and SGLT2i may help mitigate residual albuminuria and renal damage in type 2 DN. Full article

Herpes simplex virus type 1 (HSV-1) is a neurotropic alphaherpesvirus that interacts dynamically with host cells within structured tissue environments. Conventional two-dimensional (2D) cultures do not fully recapitulate these spatial and microenvironmental features. In this study, we established a three-dimensional (3D) culture system using the self-assembling peptide RADA16-I to generate an extracellular matrix–mimetic hydrogel scaffold. This platform supported the formation of stable Vero cell spheroids that remained viable for more than 30 days. Following HSV-1 infection, viral spread initiated at the spheroid periphery and progressively extended toward the core. Sustained viral replication was detected for up to 22 days, indicating long-term maintenance of infection within the 3D structure. Ultrastructural examination identified viral particles and vesicular compartments consistent with autophagy-related organelles. Comparative analysis of autophagy-associated markers revealed distinct temporal patterns between 2D monolayer cultures and 3D spheroids. In the 3D system, LC3B-II levels progressively increased, accompanied by a reduction in p62, suggesting altered regulation of autophagic flux relative to conventional 2D conditions. These findings demonstrate that the RADA16-I-based 3D culture model supports prolonged HSV-1 infection and reproduces key spatial features of viral dissemination. The differential autophagic responses observed between 2D and 3D systems highlight the influence of cellular architecture on host–virus interactions and support the application of 3D culture platforms for mechanistic studies of HSV-1 pathogenesis. Full article

JNJ-26366821, a novel thrombopoietin mimetic peptide (TPOm), is shown to increase platelets (PLTs) transiently in peripheral blood. We hypothesized that increases in PLT counts may involve stimulation of hematopoiesis via induction of cytokines, growth factors, and microRNAs. Hence, we measured various cytokines, chemokines, and growth factors in serum. Time-course analysis of G-CSF, IL-5, IL-6, IL-9, IL-10, TNFα, IL-1α, and IL-1β expression was significantly altered in the control group at 9.5 Gy compared to a lower non-lethal dose of 7 Gy on days 7 to 15 post-exposure. TPOm pre-treatment significantly ameliorated the changes in expression of these pro-inflammatory cytokines and growth factors. Additionally, we show that TPOm differentially modulates the miRNA expression profiles in the spleen of irradiated mice compared to controls at both early times as well as later times after irradiation. These results suggest a possible role of TPOm in protecting animals from radiation-induced thrombocytopenia and lethality by attenuating radiation-induced inflammatory cytokines and miRNAs. Full article

Caffeoyl hexapeptide-9 (CH-9) is a novel cosmetic peptide designed by conjugating hexapeptide-9 (H-9), a known collagen-mimetic peptide with established skin anti-aging activity, with caffeic acid (CA) via an amide bond, leveraging peptide-drug conjugate (PDC) design principles. In ultraviolet (UV)-irradiated cellular and skin models, CH-9 outperformed H-9 in preserving cell viability, restoring collagen types I, III, and IV, and suppressing interleukin-6 and -8 secretion. Additionally, its direct antioxidant activity, absent in H-9, was demonstrated in vitro by scavenging of hydroxyl and peroxyl radicals. Molecular docking indicated CH-9 interacted with the catalytic domain of matrix metalloproteinase 2 (MMP2), a key enzyme in collagen degradation during photoaging, suggesting a potential inhibition of its activity. Molecular dynamics (MD) simulations revealed an improved insertion of CH-9 into a stratum corneum (SC) lipid bilayer compared to H-9, consistent with enhanced skin permeation in vivo. Moreover, CH-9 exhibited improved aqueous and cosmetic serum stability over CA. In a 28-day clinical study, topical application of CH-9 significantly improved skin elasticity and firmness compared to H-9. This work demonstrates that the PDC-based conjugate CH-9 combines enhanced anti-photoaging efficacy with improved transdermal permeation and stability, highlighting a promising strategy for the development of advanced cosmetic ingredients. Full article

To address the challenges in wound healing, clinical management increasingly demands targeted, adaptive, responsive, and patient-centered strategies. This is especially true for wounds characterized by delayed healing and a high risk of infection. Advances in regenerative medicine and biomaterial technologies are fostering the development of multifunctional approaches that integrate tissue regeneration, antibacterial/antibiofilm activity, immunomodulation, and real-time monitoring. This paper surveys emerging platforms, including both natural and synthetic scaffolds, hydrogels enriched with platelet-derived growth factors, glycosaminoglycan mimetics, bioactive peptides (such as GHK-Cu and antimicrobial peptides), nanoscaffolds, and stimuli-responsive systems. The paper also explores cutting-edge technologies such as water-powered, electronics-free dressings that deliver localized electrical stimulation; biodegradable bioelectric sutures that produce self-sustained mechano-electrical signals; and sensory bandages that monitor pH, moisture, temperature, and bacterial contamination in real-time while enabling on-demand drug release with pro-regenerative, antibacterial, and other therapeutic functionalities. Further therapeutic approaches include natural matrices, exosomes, gene editing, 3D bioprinting, and AI-assisted design. Particular attention is paid to orthopedic applications and orthopedic implant infection. A brief section addresses the still unresolved challenge of articular cartilage regeneration. Interdisciplinary innovation, integrating insights from molecular biology through engineering, plays a central role in translating novel strategies into tailored, clinically effective wound management solutions. Full article