Therapeutic Scaffolds Research Articles

A mouse model of volumetric muscle loss and therapeutic scaffold implantation.

Skeletal myofibers naturally regenerate after damage; however, impaired muscle function can result in cases when a prominent portion of skeletal muscle mass is lost, for example, following traumatic muscle injury. Volumetric muscle loss can be modeled in mice using a surgical model of muscle ablation to study the pathology of volumetric muscle loss and to test experimental treatments, such as the implantation of acellular scaffolds, which promote de novo myogenesis and angiogenesis. Here we provide step-by-step instructions to perform full-thickness surgical ablation, using biopsy punches, and to remove a large volume of the tibialis anterior muscle of the lower limb in mice. This procedure results in a reduction in muscle mass and limited regeneration capacity; the approach is easy to reproduce and can also be applied to larger animal models. For therapeutic applications, we further explain how to implant bioscaffolds into the ablated muscle site. With adequate training and practice, the surgical procedure can be performed within 30 min.

PET Imaging Using 89Zr Labeled StarPEG Nanocarriers Reveals Heterogeneous Enhanced Permeability and Retention (EPR) in Prostate Cancer.

The enhanced permeability and retention (EPR) effect controls passive nanodrug uptake in tumors, and may provide a high tumor payload with prolonged retention for cancer treatment. However, EPR-mediated tumor uptake and distribution vary by cancer phenotype. Thus, we hypothesized that a companion PET-imaging surrogate may benefit EPR-mediated therapeutic drug delivery. We developed two 89Zr-radiolabeled nanocarriers based on 4-armed-starPEG40kDa with or without talazoparib (TLZ), a potent PARPi, as surrogates for the PEG-TLZ4 therapeutic scaffold. For PET imaging, PEG-DFB4 and PEG-DFB1-TLZ3 were radiolabeled with 89Zr by replacing one or all four TLZ on PEG-TLZ4 with deferoxamine B (DFB). The radiolabeled nanodrugs [89Zr]PEG-DFB4 and [89Zr]PEG-DFB1-TLZ3 were tested in vivo in prostate cancer subcutaneous xenografts (22Rv1, LTL-545, and LTL-610) and 22Rv1 metastatic models. Their EPR-mediated tumoral uptake and penetration was compared to CT26, a known EPR-high MicroPET/CT images, organ biodistribution, and calculated kinetic parameters showed high uptake in CT26 and LTL-545, moderate to low uptake in LTL-610 and 22Rv1. MicroPET/CT and high-resolution autoradiographic images showed nanocarrier penetration into highly permeable CT26, but heterogeneous peripheral accumulation was observed in LTL-545, LTL-610, and 22Rv1 subcutaneous xenografts and metastatic tumors. CD31 staining of tumor sections showed homogenous vascular development in CT26 tumors and heterogeneity in other xenografts. Both [89Zr]PEG-DFB4 and [89Zr]PEG-DFB1-TLZ3 showed similar accumulation and distribution in subcutaneous and metastatic tumor models. Both nanocarriers can measure tumor model passive uptake heterogeneity. Although heterogeneous, prostate cancer xenografts had low EPR. These starPEG nanocarriers could be used as PET imaging surrogates to predict drug delivery and efficacy.

Novel purine derivatives as selective CDK2 inhibitors with potential anticancer activities: Design, synthesis and biological evaluation

Purine analogues were discovered to be inhibitors of CDK2, suggesting a potential therapeutic scaffold. This paper addresses the design, synthesis, and anticancer evaluation of purine analogues as kinase inhibitors. In the early stages of the investigation, the designed compounds demonstrated a promising docking score and greater protein–ligand stability in MD simulation than the standard, indicating a higher affinity against CDK2. Thus, we synthesised new purine analogues under simple and optimised reaction conditions. Among the studies under NCI-60, 5g and 5i were the most effective, with a percentage GI of 98.09 and 90 against OVCAR-4 and SNB-75, respectively, at a dose of 10 µM. Additionally, 5g and 5i demonstrated 7.80-fold and 1.54-fold greater cytotoxicity against PA-1 and MCF-7, with IC50s of 1.08 µM and 3.54 µM, respectively, compared to seliciclib (8.43 µM and 5.46 µM). In addition, 5g and 5i showed selective cytotoxicity against PA-1 and MCF-7 than normal cells, with selectivity indexes of 26.40 and 15.45, respectively, as compared to the standard (SI=3.83 and 5.91). In the kinase selectivity assay, both compounds demonstrated greater affinity against CDK2 than other kinases, with IC50 of 0.21 µM and 0.59 µM, in contrast to the standard (IC50 = 0.63 µM). Furthermore, 5g confirmed kinase inhibition in the western blot by lowering CDK2, cyclin A2, and other downstream substrates. Moreover, it triggered cell death by apoptosis and cell cycle arrest in G2/M. Taken together, 5g merits further investigation in PKPD research to discover a potential therapeutic candidate against cancer.

PIM Kinase Inhibitors as Novel Promising Therapeutic Scaffolds in Cancer Therapy

Cancer involves the uncontrolled, abnormal growth of cells and affects other tissues. Kinase has an impact on proliferating the cells and causing cancer. For the purpose of treating cancer, PIM kinase is a potential target. The pro-viral Integration site for moloney murine leukaemia virus (PIM) kinases is responsible for the tumorigenesis, by phosphorylating the proteins that control the cell cycle and cell proliferation. PIM-1, PIM-2, and PIM-3 are the three distinct isoforms of PIM kinases. The JAK/STAT pathway is essential for controlling how PIM genes are expressed. PIM kinase is also linked withPI3K/AKT/mTOR pathway in various types of cancers. The overexpression of PIM kinase will cause cancer. Currently, there are significant efforts being made in medication design and development to target its inhibition. A few small chemical inhibitors (E.g., SGI-1776, AZD1208, LGH447) that specifically target the PIM proteins' adenosine triphosphate (ATP)-binding domain have been identified. PIM kinase antagonists have a remarkable effect on different types of cancer. Despite conducting clinical trials on SGI-1776, the first PIM inhibitory agent, was prematurely withdrawn, making it unable to generate concept evidence. On the other hand, in recent years, it has aided in hastening the identification of multiple new PIM inhibitors. Cyanopyridines and Pyrazolo[1,5-a]pyrimidinecan act as potent PIM kinase inhibitors for cancer therapy. We explore the involvement of oncogenic transcription factor c-Mycandmi-RNA in relation to PIM kinase. In this article, we highlight the oncogenic effects, and structural insights into PIM kinase inhibitors for the treatment of cancer.

A potent therapeutic scaffold fusing quinazolinone/melatonin for future colorectal cancer interventions: design, one-pot synthesis, biological and ADME-tox modeling studies

AbstractColorectal cancer is one of the most incident and lethal cancers in the world. The search for new compounds to treat this disease is being motivated by the occurrence of side effects and the rising in the resistance to chemotherapy. We synthesized a new class of conjugates bearing quinazolinone and melatonin which were prepared in good yields (63–93%) through one-pot three-component approach. quinazolinone/melatonin conjugates were proved against SW480 human colorectal adenocarcinoma cells and non-malignant colonic cells (NCM460). The cytotoxic and antiproliferative activities were determined through the sulforhodamine B assay. Compounds 1f, 1g and 1i–l displayed the best activity, being hybrids 1i–l the most selective against malignant cells, causing either a cytostatic and/or cytotoxic effect with evident morphological changes. Moreover, a theoretical drug-like/pharmacokinetics/toxicological study suggested that the hit-promising compounds 1i and 1j would have a great chance to advance to further preclinical studies as anti-cancer therapeutic candidate for oral oncological management. Our study evidently identified the potency of these quinazolinone/melatonin hybrids to be a prototype drug for further investigations toward novel therapeutics treatments of colorectal cancer.

Self-adaptive bioactive scaffolds orchestrate diabetic microenvironment remodeling and vascularized bone regeneration

The repair of diabetic bone defects is still challenging as the innate healing process is impaired by adverse microenvironments such as excessive reactive oxygen species (ROS) and insufficient angiogenesis and osteogenesis. Herein, a self-adaptive biocomposite scaffold that can orchestrate sequential regulation of diabetic microenvironment and vascularized bone regeneration was developed for efficient diabetic bone defect repair. The therapeutic scaffold system was meticulously constructed through the incorporation of hydrogel and 3D-printed architecture. In response to the multiple diabetic microenvironment (high level of glucose and ROS), the hydrogel consisting of Vitamin C-loaded phenylboric acid-grafted poly (glutamic acid)/poly (vinyl alcohol) showed adaptive degradation and antioxidative properties by scavenging the intracellular ROS, as well as promoting M2 polarization of macrophages. Furthermore, the copper-doped bioactive glass-contained 3D-printed polycaprolactone within the scaffold system was demonstrated to enhance the mechanical strength and stimulate the in vitro angiogenic and osteogenic performance by releasing copper and silicon ions. Moreover, in a diabetic rat femoral defect model, the biocomposite scaffold showed better angiogenesis and bone regeneration by following diabetic microenvironment remodeling. Therefore, the designed self-adaptive biocomposite scaffold can promote diabetic bone regeneration by sequentially regulating pathological and regenerative cues. This study offers vital insight into the design of a self-adaptive bioactive scaffold for the treatment of diabetic bone defects.

Injectable Dual Fenton/Enzymatically Cross-Linked Double-Network Hydrogels Based on Acrylic/Phenolic Polymers with Highly Reinforced and Tunable Mechanical Properties.

Injectable hydrogels have been extensively used as promising therapeutic scaffolds for a wide range of biomedical applications, such as tissue regeneration and drug delivery. However, their low fracture toughness and brittleness often limit their scope of application. Double-network (DN) hydrogel, which is composed of independently cross-linked rigid and ductile polymer networks, has been proposed as an alternative technique to compensate for the weak mechanical properties of hydrogels. Nevertheless, some challenges still remain, such as the complicated and time-consuming process for DN formation, and the difficulty in controlling the mechanical properties of DN hydrogels. In this study, we introduce a simple, rapid, and controllable method to prepare in situ cross-linkable injectable DN hydrogels composed of acrylamide (AAm) and 4-arm-PPO-PEO-tyramine (TTA) via dual Fenton- and enzyme-mediated reactions. By varying the concentration of Fenton's reagent, the DN hydrogels were rapidly formed with controllable gelation rate. Importantly, the DN hydrogels showed a 13-fold increase in compressive strength and a 14-fold increase in tensile strength, compared to the single network hydrogels. The mechanical properties, elasticity, and plasticity of DN hydrogels could also be modulated by simply varying the preparation conditions, including the cross-linking density and reagent concentrations. At low cross-linker concentration (<0.05 wt %), the plastic DN hydrogel stretched to over 6,500%, whereas high cross-linker concentration (≥0.05 wt %) induced fully elastic hydrogels, without hysteresis. Besides, DN hydrogels were endowed with rapid self-recovery and highly enhanced adhesion, which can be further applied to wearable devices. Moreover, human dermal fibroblasts treated with DN hydrogels retained viability, demonstrating the biocompatibility of the cross-linking system. Therefore, we expect that the dual Fenton-/enzyme-mediated cross-linkable DN hydrogels offer great potential as advanced biomaterials applied for hard tissue regeneration and replacement.

Customized Flexible Osteoid Electrode for Traumatic Brain Injury Induced Posttraumatic Epilepsy Monitoring

AbstractTraumatic brain injury (TBI)‐induced post‐traumatic epilepsy (PTE) is a serious brain disease that causes the loss of motor functions, cognitive impairments, and even death. Real‐time and long‐term electrophysiological signal monitoring has significant implication for the treatment of patient with TBI. Brain–computer interfaces (BCIs) utilizing flexible electrodes enable accurate epilepsy identification by electrocorticography (ECoG) signal monitoring. In this study, a customized flexible osteoid electrode is developed, which contributes to demands and personal differentiation among patients with TBI. The end product of osteoid electrode after full osseointegration will be a stable and firmly integrated structure within the bone tissue, providing a secure platform for continuous electrophysiological signal monitoring. The flexibility and conductivity of the osteoid electrode enables high‐quality and long‐term epilepsy monitoring. Biocompatibility of the osteoid electrode is also demonstrated by in vitro cell experiments. Simultaneously, the porous osteoid electrode also exhibits osseointegration ability based on potential long‐term ECoG signal monitoring, which suggests its potential for the comprehensive treatment of TBI patients. This work not only introduces a potential therapeutic scaffold for TBI‐related diseases, but also provides promising techniques for clinical ECoG monitoring in patients with TBI.

A Review on Indole as a Cardinal Scaffold for Anticancer Drugs Development

Abstract: Chemotherapy is the mainstay of therapeutic cancer therapy; however, the development of resistance typically makes it less effective. There are continuous efforts by researchers to find novel lead compounds with potent anti-cancer activity. Generally, synthetic or natural heterocyclic compounds have been investigated in detail as a scaffold for cancer therapeutics. Among them, indole, owing to its unique physiochemical and biological properties, provides a promising platform for the development of pharmacophores for drug development against cancer, acting via various mechanisms. Till now, several indole-based derivatives have been identified as anti-cancer agents, which are either being used in clinics or are in various phases of clinical trials, suggesting their importance in anti-cancer drug development. These anti-cancer drugs have been classified into different classes depending on their mechanism of action. For example, histone deacetylase inhibitors (HDAC inhibitors), silent mating type information regulation 2 homolog (SIRT) inhibitors, tubulin inhibitors, proviral insertion site in Moloney murine leukemia virus (Pim) inhibitors, DNA Topoisomerase inhibitors, and kinase inhibitors. In this review, the author's approach is to compile the recent developments on indole-based anti-cancer drugs and provide insight into the respective structureactivity relationships (SARs) of the compounds. We hope the review will provide a thorough understanding to the reader and guide to developing novel and potent indole-based anticancer agents against drug-sensitive and drug-resistant cancer in the future.

Breaking the Tumor Chronic Inflammation Balance with a Programmable Release and Multi-Stimulation Engineering Scaffold for Potent Immunotherapy.

Tumor-associated chronic inflammation severely restricts the efficacy of immunotherapy in cold tumors. Here, a programmable release hydrogel-based engineering scaffold with multi-stimulation and reactive oxygen species (ROS)-response (PHOENIX) is demonstrated to break the chronic inflammatory balance in cold tumors to induce potent immunity. PHOENIX can undergo programmable release of resiquimod and anti-OX40 under ROS. Resiquimod is first released, leading to antigen-presenting cell maturation and the transformation of myeloid-derived suppressor cells and M2 macrophages into an antitumor immune phenotype. Subsequently, anti-OX40 is transported into the tumor microenvironment, leading to effector T-cell activation and inhibition of Treg function. PHOENIX consequently breaks the chronic inflammation in the tumor microenvironment and leads to a potent immune response. In mice bearing subcutaneous triple-negative breast cancer and metastasis models, PHOENIX effectively inhibited 80% and 60% of tumor growth, respectively. Moreover, PHOENIX protected 100% of the mice against TNBC tumor rechallenge by electing a robust long-term antigen-specific immune response. An excellent inhibition and prolonged survival in PHOENIX-treated mice with colorectal cancer and melanoma is also observed. This work presents a potent therapeutic scaffold to improve immunotherapy efficiency, representing a generalizable and facile regimen for cold tumors.

Design of molecular inhibitors against the NuoC protein of Mycobacterium tuberculosis.

Tuberculosis (TB) is one of the main health issues for the international scientific community. The NADH- quinone oxidoreductase subunit C (NuoC) protein belongs to the NADH dehydrogenase family, which plays a critical role in the electron transport chain and ATP synthesis and energy production in Mycobacterium tuberculosis (Mtb). In the present study, Nuoc protein is considered a potential drug target for identifying inhibitors for the protein. The Nuoc protein’s 3D structural features are determined using computational techniques, including active site identification, ADME properties and virtual screening. The NuoC theoretical model was developed using homology modeling techniques and its structure was verified by various validation methods. They provide insight into the conformational changes occurring in the NuoC protein. To identify drug-like compounds virtual screening studies were conducted around the active site using several ligand databases. According to the research residues the amino acid residues ARG98, ARG75 (basic), ASP99, ASP189, ASP98 (acidic), LEU101, LEU194 (nonpolar neutral), THR180 (polar neutral), GLU177(polar neutral), TYR181(polar neutral), PRO102, PRO192 (nonpolar neutral), and HIS191(basic) are important in drug-target interactions. Additionally, docking experiments of TB medications against NuoC were carried out. The study found that the ADME parameters of the selected ligand molecules are more favourable compared to existing TB drugs. This highlights the drug-like activity of the ligand molecules in inhibiting NuoC proteins. The structural data, along with the information about the active site and the selected ligand molecules, can help in identifying new therapeutic scaffolds for the treatment of Tuberculosis.

A Promising Therapeutic Scaffold Fusing Chalcone/Coumarin Targeting Colorectal Cancer: Design, Synthesis, Biological and ADME‐tox Modelling

AbstractEight novel compounds incorporating chalcone and coumarin features, namely chalcone‐coumarin‐ hybrid molecules, were designed, synthetized, and evaluated for their activity against human colorectal carcinoma SW480 cell line. According to the results observed, the hybrid with a 2,3‐dimetoxysubstitution pattern displayed the highest activity at the conditions evaluated, with an IC50 value of 25.18±1.12 μM, being even more active than the reference drug (5‐fluorouracil) and the parental compound (7‐methylcoumarin). In addition, this hybrid compound exhibited significant antiproliferative activity in a time‐ and concentration dependent way, suggesting rather a cytostatic or cytotoxic effect. Moreover, a theoretical drug‐like/pharmacokinetics/toxicological study suggested that the most promising hybrid would have a great chance to advance to further preclinical studies as anti‐cancer therapeutic candidate for oral oncological management. Our study evidently identified the potency of chalcone‐coumarin conjugates, particularly the 2,3‐dimetoxysubstituited molecule to be a prototype drug for further investigations toward novel therapeutics treatments of colorectal cancer.

Endogenous Calcium-Supported dynamic Copper(II)-Crosslinked Gel depot for in situ disulfiram activation and synergistic cancer therapy

The development of smart therapeutic scaffolds to improve chemotherapeutic efficacy and enhance antitumor immunity remains a considerable challenge. In this study, we engineered a therapeutic copper ion-crosslinked gel depot based on alginate to enhance disulfiram (DSF)-mediated cancer chemoimmunotherapy. This gel depot maintained structural stability through ion coordination exchange with the calcium ions in body fluids and continuously created an antitumor diethyldithiocarbamate-copper complex (CuET), which led to the sustained release of various therapeutic agents in vivo. The generated CuET not only had a direct antitumor effect due to its cytotoxicity but also effectively induced the immunogenic death of cancer cells. These factors coregulated the immunosuppressed tumor microenvironment with the released DSF, thus sensitizing the systemic immune response and improving the efficacy of anti-programmed cell death-ligand 1 antibody (aPD-L1)-mediated immune checkpoint blockade. The results indicated that this endogenous calcium-supported therapeutic copper(II)-crosslinked gel depot could effectively improve the tumor immune microenvironment, leading to enhanced synergistic antitumor efficacy in vivo.

Exosomes derived from tumor adjacent fibroblasts efficiently target pancreatic tumors

The application of extracellular vesicles, particularly exosomes (EXs), is rapidly expanding in the field of medicine, owing to their remarkable properties as natural carriers of biological cargo. This study investigates utilization of exosomes derived from stromal cells of tumor adjacent normal tissues (NAF-EXs) for personalized medicine, which can be derived at the time of diagnosis by endoscopic ultrasound. Herein, we show that exosomes (EXs) derived from NAFs demonstrate differential bio-physical characteristics, efficient cellular internalization, drug loading efficiency, pancreatic tumor targeting and delivery of payloads. NAF-derived EXs (NAF-EXs) were used for loading ormeloxifene (ORM), a potent anti-cancer and desmoplasia inhibitor as a model drug. We found that ORM maintains normal fibroblast cell phenotype and renders them incompatible to be triggered for a CAF-like phenotype, which may be due to regulation of Ca2+ influx in fibroblast cells. NAF-EXs-ORM effectively blocked oncogenic signaling pathways involved in desmoplasia and epithelial mesenchymal transition (EMT) and repressed tumor growth in xenograft mouse model. In conclusion, our data suggests preferential tropism of NAF-EXs for PDAC tumors, thus imply feasibility of developing a novel personalized medicine for PDAC patients using autologous NAF-EXs for improved therapeutic outcome of anti-cancer drugs. Additionally, it provides the opportunity of utilizing this biological scaffold for effective therapeutics in combination with standard therapeutic regimen.

Disulfide-constrained peptide scaffolds enable a robust peptide-therapeutic discovery platform.

Peptides present an alternative modality to immunoglobulin domains or small molecules for developing therapeutics to either agonize or antagonize cellular pathways associated with diseases. However, peptides often suffer from poor chemical and physical stability, limiting their therapeutic potential. Disulfide-constrained peptides (DCP) are naturally occurring and possess numerous desirable properties, such as high stability, that qualify them as drug-like scaffolds for peptide therapeutics. DCPs contain loop regions protruding from the core of the molecule that are amenable to peptide engineering via direct evolution by use of phage display technology. In this study, we have established a robust platform for the discovery of peptide therapeutics using various DCPs as scaffolds. We created diverse libraries comprising seven different DCP scaffolds, resulting in an overall diversity of 2 x 1011. The effectiveness of this platform for functional hit discovery has been extensively evaluated, demonstrating a hit rate comparable to that of synthetic antibody libraries. By utilizing chemically synthesized and in vitro folded peptides derived from selections of phage displayed DCP libraries, we have successfully generated functional inhibitors targeting the HtrA1 protease. Through affinity maturation strategies, we have transformed initially weak binders against Notch2 with micromolar Kd values to high-affinity ligands in the nanomolar range. This process highlights a viable hit-to-lead progression. Overall, our platform holds significant potential to greatly enhance the discovery of peptide therapeutics.

Harnessing Engineered Extracellular Vesicles from Mesenchymal Stem Cells as Therapeutic Scaffolds for Bone‐Related Diseases

AbstractMesenchymal stem cells (MSCs) play a crucial role in maintaining bone homeostasis and are extensively explored for cell therapy in various bone‐related diseases. In addition to direct cell therapy, the secretion of extracellular vesicles (EVs) by MSCs has emerged as a promising alternative approach. MSC‐derived EVs (MSC‐EVs) offer equivalent therapeutic efficacy to MSCs while mitigating potential risks. These EVs possess unique properties that enable them to traverse biological barriers and deliver bioactive cargos to target cells. Furthermore, by employing modification and engineering strategies, the therapeutic effects and tissue targeting specificity of MSC‐EVs can be further enhanced to meet specific therapeutic needs. In this review, the mechanisms and advantages of MSC‐EV therapy in diseased bone tissues are highlighted. Through simple isolation and modification techniques, MSC‐EV‐based biomaterials have demonstrated great promise for bone regeneration. Finally, future perspectives on MSC‐EV therapy are presented, envisioning the development of next‐generation regenerative materials and bioactive agents for clinical translation in the field of bone regeneration.

Synthesis, Kinetics and Computational Explorations of 4-Phenylpiperazine Bearing N-(Aryl)-3-substituted-benzamides as Auspicious Tyrosinase Inhibitors.

In the aimed research study, a new series of N-(aryl)-3-[(4-phenyl-1-piperazinyl)methyl]benzamides was synthesized, which was envisaged as tyrosinase inhibitor. The structures of these newly designed molecules were verified by IR, 1H-NMR, 13C-NMR, EI-MS and CHN analysis data. These molecules were screened against tyrosinase and their inhibitory activity explored that these 3-substituted-benzamides exhibit good to excellent potential, comparative to the standard. The Kinetics mechanism was investigated through Lineweaver-Burk plots which depicted that molecules inhibited this enzyme in a competitive mode. Moreover, molecular docking was also performed to determine the binding interaction of all synthesized molecules (ligands) with the active site of tyrosinase enzyme and the results showed that most of the ligands exhibited efficient binding energy values. Therefore, it is anticipated that these molecules might serve as auspicious therapeutic scaffolds for treatment of the tyrosinase associated skin disorders.

Hybrid gelatin-ascorbyl phosphate scaffolds accelerate diabetic wound healing via ROS scavenging, angiogenesis and collagen remodeling

Skin wound healing, particularly diabetic wound healing, is challenging in clinical management. Impaired wound healing is associated with persistent oxidative stress, altered inflammatory responses, unsatisfactory angiogenesis and epithelialization. Magnesium ascorbyl phosphate (MAP), which is an ascorbic acid derivative and active ingredient in cosmetics, has been reported to scavenge reactive oxygen species (ROS), and is considered a potential therapeutic agent for diabetic wounds. Herein, we report a hybrid gelatin-MAP scaffolds that can reduces oxidative stress damage, enhances angiogenesis and collagen remodeling to accelerate diabetic wound repair. Preliminary insights based on network pharmacology indicate that MAP may accelerate wound repair through multiple biological pathways, including extracellular matrix remodeling and anti-apoptosis. In vitro studies showed that the hybrid hydrogel scaffold had suitable mechanical properties, excellent biocompatibility and bioactivity. Further animal experiments demonstrated that the hydrogel accelerated full-thickness wound repair in diabetic mice (repair rate MAP vs Control=91.791±3.306 % vs 62.962±6.758 %) through antioxidant, neuroangiogenesis, collagen remodeling, and up-regulated the expression of the related factors COL-1, CD31, VEGF, and CGRP. Overall, we developed a bioactive hybrid hydrogel encapsulating MAP that synergistically promotes diabetic wound repair through multiple biological effects. This potentially integrated therapeutic scaffold may enrich future surgical approaches for treating diabetic wounds.

Biocatalytic cyclization of small macrolactams by a penicillin-binding protein-type thioesterase.

Macrocyclic peptides represent promising scaffolds for chemical tools and potential therapeutics. Synthetic methods for peptide macrocyclization are often hampered by C-terminal epimerization and oligomerization, leading to difficult scalability. While chemical strategies to circumvent this issue exist, they often require specific amino acids to be present in the peptide sequence. Herein, we report the characterization of Ulm16, a peptide cyclase belonging to the penicillin-binding protein-type class of thioesterases that catalyze head-to-tail macrolactamization of nonribosmal peptides. Ulm16 efficiently cyclizes various nonnative peptides ranging from 4 to 6 amino acids with catalytic efficiencies of up to 3 × 106 M-1 s-1. Unlike many previously described homologs, Ulm16 tolerates a variety of C- and N-terminal amino acids. The crystal structure of Ulm16, along with modeling of its substrates and site-directed mutagenesis, allows for rationalization of this wide substrate scope. Overall, Ulm16 represents a promising tool for the biocatalytic production of macrocyclic peptides.

Estimation of apigenin from Abrus precatorius Linn. leaves extract by validated HPTLC densitometric method coupled with mass spectrometry

Abrus precatorius Linn. is recognised as Indian liquorice, valued for its medicinal properties, containing apigenin, a promising therapeutic scaffold, however, its quantification is lacking. Hence, this study established and validated the high-performance thin layer chromatography method for quantitation of apigenin from methanolic extract of A. precatorius leaves (APM). The optimised mobile phase was toluene: ethyl acetate: formic acid (6:3:1, v/v/v) for separation of apigenin. Apigenin was also confirmed by tandem mass spectrometry. The developed method was sensitive with correlation coefficient (r2 = 0.998) with limit of detection and quantification of 12.66 and 38.38 ng/band respectively. APM extract contained 0.559% w/w apigenin. Spectroscopic analysis confirmed apigenin with m/z value of 271.3. This method has been reported for the first time and proven accurate, precise and specific. As apigenin is a promising therapeutic agent, the established method can be used for quality control and be a template for drug formulation.