Mechanism Of Action Research Articles

A Potential Role for Oridonin in Cancer Control: Mechanisms of Autophagy and Apoptosis.

Cancer is one of the leading causes of mortality and morbidity worldwide. It is characterized by unmanaged cell proliferation and growth, leading to tumour formation with the potential to metastasize to various organs of the human body. Currently, several common therapeutic approaches exist to treat malignancies, including chemotherapy, surgery, and radi-otherapy, which can be used to prevent the progression of malignancies. However, these ther-apeutic approaches often face challenges due to their cytotoxic impacts and various side ef-fects. Ergo is currently researching a new treatment that effectively reduces cancer progression with minimal side effects. Emerging evidence suggests that harnessing herbal sources, which are both accessible and safe, can be useful in improving various disorders, including cancer. Oridonin, a diterpenoid isolated from the traditional Chinese medicinal herb Rabdosia ru-bescens, has shown significant potential in cancer therapy. Moreover, numerous pharmacolog-ical and biological capacities have been attributed to this naturally active compound, such as anti-oxidative, anti-inflammatory, anti-bacterial, and anti-viral influences. This review sum-marizes the current knowledge on oridonin's mechanisms of action, particularly its effects on autophagy and apoptosis. While apoptosis is a well-established pathway for eliminating cancer cells through DNA fragmentation, autophagy plays a complex role, acting as both a cytopro-tective and cell death mechanism depending on the context. We provide a comprehensive evaluation of the relevant studies, highlighting oridonin's potential in cancer control and iden-tifying areas for further research.

Molecular and energetic analysis of the interaction and specificity of Maximin 3 with lipid membranes: In vitro and in silico assessments.

In this study, the interaction of antimicrobial peptide Maximin 3 (Max3) with three different lipid bilayer models was investigated to gain insight into its mechanism of action and membrane specificity. Bilayer perturbation assays using liposome calcein leakage dose-response curves revealed that Max3 is a selective membrane-active peptide. Dynamic light scattering recordings suggest that the peptide incorporates into the liposomal structure without producing a detergent effect. Langmuir monolayer compression assays confirmed the membrane inserting capacity of the peptide. Attenuated total reflection-Fourier transform infrared spectroscopy showed that the fingerprint signals of lipid phospholipid hydrophilic head groups and hydrophobic acyl chains are altered due to Max3-membrane interaction. On the other hand, all-atom molecular dynamics simulations (MDS) of the initial interaction with the membrane surface corroborated peptide-membrane selectivity. Peptide transmembrane MDS shed light on how the peptide differentially modifies lipid bilayer properties. Molecular mechanics Poisson-Boltzmann surface area calculations revealed a specific electrostatic interaction fingerprint of the peptide for each membrane model with which they were tested. The data generated from the in silico approach could account for some of the differences observed experimentally in the activity and selectivity of Max3.

An Extensive Computational Investigation of Mycobacterium tuberculosis Pantothenate Synthetase Inhibitors from Diverse‐Lib Compounds Library

AbstractAntibiotics have played a crucial role in significantly reducing the incidence of tuberculosis (TB) infection worldwide. Even before the mid‐20th century, the mortality rate of TB onset within five years was around 50 %. So, the introduction of antibiotics has changed the scenario of TB from a serious threat to a manageable one. However, the emergence of resistance to anti‐TB drugs poses a significant challenge. So, to overcome this situation the therapeutic approaches and drug targets need to be reformed. This study focused on finding potential inhibitors by targeting Pantothenate Synthetase, a crucial enzyme for Mycobacterium tuberculosis (Mtb) survival, through computational drug discovery methods. Molecular docking and virtual screening were employed to identify potential inhibitors from Diverse‐lib. Four compounds, namely CID2813602, 24357538, CID753354, and CID4798023, exhibited strong binding energies and stable interaction with the target protein. Further assessment of these compounds through MD simulation and Post MD simulation showed significant dynamic stability. The minimum energy transition calculated using the free energy landscape analysis of these compounds when docked with Pantothenate Synthetase confirmed the stability of each complex due to its minimum energy production. The free binding energy calculation of each complex also showed the intramolecular interaction contributes to the strong binding affinity of the compounds within the enzyme's active site clarifying their mechanisms of action. This research showcases the effectiveness of computational methods in promptly identifying potential anti‐TB drugs, paving the way for future experimental validation and optimization. It holds promise for the development of new treatments targeting drug‐resistant TB strains.

Application of polymer adhesive hydrogel in wound healing

As the global adhesive industry continues to grow, researchers are discovering that polymer adhesives are playing an increasing role in the medical field, polymer adhesives have attracted more and more attention from the medical industry due to their unique advantages, such as hydrogels, have gradually appeared, which can effectively help wound healing. Most of the hydrogels have good biocompatibility and water absorption, and have the advantages of controllable structure, adjustable performance and easy degradation. Compared with traditional wound healing methods, hydrogels effectively reduce additional trauma and leakage and allow for greater tissue integration. This paper reviews the types of polymeric adhesive hydrogels and examples of some of them being artificially modified to be applied to the field of wound healing. Analyzes their mechanism of action and the advantages and shortcomings of their clinical applications, and finally looks into the potential functions and clinical efficacy of hydrogels in the future.

Expanding the antiprotozoal activity and the mechanism of action of n-butyl and iso-butyl ester of quinoxaline-1,4-di-N-oxide derivatives against Giardia lamblia, Trichomonas vaginalis, and Entamoeba histolytica. An in vitro and in silico approach

In this study, n-butyl and iso-butyl quinoxaline-7-carboxylate-1,4-di-N-oxide derivatives were evaluated in vitro against Giardia lamblia (G. lamblia), Trichomonas vaginalis (T. vaginalis), and Entamoeba histolytica (E. histolytica). The potential mechanism of action determination was approached by in silico analysis on G. lamblia and T. vaginalis triosephosphate isomerase (GlTIM and TvTIM, respectively), and on E. histolytica thioredoxin reductase (EhTrxR). Enzyme inactivation assays were performed on recombinant GlTIM and EhTrxR. Compound T-167 showed the best giardicidal activity (IC50 = 25.53 nM) and the highest inactivation efficiency against GlTIM without significantly perturbing its human homolog. Compounds T-142 and T-143 showed the best amoebicidal (IC50 = 9.20 nM) and trichomonacidal (IC50 = 45.20 nM) activity, respectively. Additionally, T-143 had a high activity as giardicial (IC50 = 29.13 nM) and amoebicidal (IC50 = 15.14 nM), proposing it as a broad-spectrum antiparasitic agent. Compounds T-145, and T-161 were the best EhTrxR inhibitors with IC50 of 16 µM, and 18 µM, respectively.

Emerging Frontiers in Cancer Immunotherapy: Recent Advances in CAR-NK Cell and CAR-Macrophage Therapies

Chimeric antigen receptor (CAR) cell therapies have revolutionized the field of cancer treatment with the breakthrough successes of CAR-T cell therapy in hematological malignancies. However, CAR-T cell efficacy in solid tumors has been limited by challenges such as the immunosuppressive tumor microenvironment (TME) and safety concerns like cytokine release syndrome (CRS) and graft-versus-host disease (GvHD). This review focuses on the latest advancements in CAR-NK cell and CAR-macrophage therapies, which offer potential solutions to these limitations. CAR-NK cells exhibit natural cytotoxicity and MHC-independent tumor targeting, providing a safer profile with lower risks of GvHD and CRS compared to CAR-T cells. Innovations in CAR-NK cell therapy includes structural optimizations, gene editing with CRISPR-Cas9, and the development of multispecific CARs, all contributing to enhanced anti-tumor efficacy, especially in solid tumors. Meanwhile, CAR-macrophages are effective in remodeling the TME through phagocytosis and immune activation, addressing the challenges of solid tumor infiltration. This review compares the mechanisms of action, clinical applications, and safety profiles of CAR-NK cells and CAR-macrophages, highlighting the synergistic potential of these therapies. Although clinical research on both therapies is still in its early stages, the promising preclinical and early clinical trial results underscore their potential as alternative immunotherapies for refractory cancers. Future research will focus on overcoming challenges in production scalability, improving in vivo persistence, and personalizing CAR therapies through precision medicine approaches. These two therapies will likely play pivotal roles in the next generation of cancer immunotherapies.

The Association of High Burden Premature Ventricular Contractions with Esophageal/Upper GI Diseases

Six patients in our clinical program who were diagnosed with high burden (>10%) premature ventricular contractions (PVCs) and concomitant significant upper GI disease with no other significant cardiac history demonstrated a significant reduction in the burden of PVCs following surgical or procedural interventions of the upper GI tract (68.34% reduction, p = 0.024). Furthermore, in all cases, the origin of the PVCs was from the base of the right ventricular outflow tract (RVOT). This is the first report in the literature that we are aware of that makes the unique association that we propose a dual mechanism of action of the upper GI and vagally mediated PVCs and through direct, anatomical extrinsic triggering of the right ventricular outflow tract (RVOT) of the heart. These are very preliminary findings that warrant larger clinical and mechanistic studies that if confirmed, may define a new physiologic subset of PVCs for which we propose a new term, “E-PVCs”.

Transcriptome Sequencing-Based Screening of Key Melatonin-Related Genes in Ischemic Stroke

Ischemic stroke (IS) is a complex syndrome of neurological deficits due to stenosis or occlusion of the carotid and vertebral arteries for which there is still no effective treatment. Melatonin, a hormone secreted by the pineal gland, has multiple biological effects, such as antioxidant and anti-inflammatory properties, circadian rhythm regulation, and tissue regeneration, demonstrating potential applications in the treatment of IS. The aim of this study was to investigate key melatonin-regulated genes associated with IS using transcriptome sequencing and bioinformatics analyses and to explore their potential mechanisms of action in the disease process. We obtained gene expression data related to ischemic stroke (IS) from the Gene Expression Omnibus (GEO) database and identified candidate genes using machine learning algorithms. We then assessed the predictive power of these genes using PPI network analysis and diagnostic models. Finally, a series of enrichment analyses identified four key genes: ADM, PTGS2, MMP9, and VCAN. In addition, we determined the mRNA levels of these four key genes in an IS rat model using qPCR and found that all of these genes were significantly upregulated in the IS model compared to the control group, which is consistent with the results of previous analyses. Meanwhile, these genes have biological functions such as regulating vascular tone, participating in the inflammatory response, influencing tissue remodeling, and regulating cell adhesion and proliferation, playing key roles in the pathogenesis of IS. Therefore, we suggest that these four key genes may serve as prospective biomarkers for IS and help predict the risk of developing IS. In conclusion, this study elucidates for the first time the potential role of melatonin in the pathogenesis of IS and lays the foundation for in-depth studies on the functions of these key genes in the pathophysiology of IS and their potential applications in clinical diagnosis and treatment.

Modelling hemodynamics regulation in rats and dogs to facilitate drugs safety risk assessment

Pharmaceutical companies routinely screen compounds for hemodynamics related safety risk. In vitro secondary pharmacology is initially used to prioritize compounds while in vivo studies are later used to quantify and translate risk to humans. This strategy has shown limitations but could be improved via the incorporation of molecular findings in the animal-based toxicological risk assessment. The aim of this study is to develop a mathematical model for rat and dog species that can integrate secondary pharmacology modulation and therefore facilitate the overall pre-clinical safety translation assessment. Following an extensive literature review, we built two separate models recapitulating known regulation processes in dogs and rats. We describe the resulting models and show that they can reproduce a variety of interventions in both species. We also show that the models can incorporate the mechanisms of action of a pre-defined list of 50 pharmacological mechanisms whose modulation predict results consistent with known pharmacology. In conclusion, a mechanistic model of hemodynamics regulations in rat and dog species has been developed to support mechanism-based safety translation in drug discovery and development.

Exploring the Prebiotic Potentials of Hydrolyzed Pectins: Mechanisms of Action and Gut Microbiota Modulation

The intestinal microbiota is a complex ecosystem where the microbial community (including bacteria) can metabolize available substrates via metabolic pathways specific to each species, often related in symbiotic relations. As a consequence of using available substrates and microbial growth, specific beneficial metabolites can be produced. When this reflects the health benefits for the host, these substrates can be categorized as prebiotics. Given that most prebiotic candidates must have a low molecular weight to be further metabolized by the microbiota, the role in the preliminary biological pretreatment is crucial. To provide proper substrates to the intestinal microbiota, a strategy could be to decrease the complexity of polysaccharides and reduce the levels of polymerization to low molecular weight for the target molecules, driving better solubilization and the consequent metabolic use by intestinal bacteria. When high molecular weight pectin is degraded (partially depolymerized), its solubility increases, thereby improving its utilization by gut microbiota. With regards to application, prebiotics have well-documented advantages when applied as food additives, as they improve gut health and can enhance drug effects, all shown by in vitro, in vivo, and clinical trials. In this review, we aim to provide systematic evidence for the mechanisms of action and the modulation of gut microbiota by the pectin-derived oligosaccharides produced by decreasing overall molecular weight after physical and/or chemical treatments and to compare with other types of prebiotics.

A Network Pharmacological Study of Qianjin Sanhuang Decoction in the Treatment of Osteoarthritic Knee Disease

Objective: To predict the action targets of Qianjin Sanhuang decoction in the treatment of knee osteoarthritis through network pharmacology, to explore its potential multi component, multi target, multi, pathway mechanism of action, and to elaborate the relationship between the pharmacological effects of the drug and the disease from the perspective of molecular mechanism. Methods: The Chinese herbal composition of Qianjin Sanhuang decoction was determined by reading ancient texts and reviewing data, and the chemical components of Qianjin Sanhuang decoction were collected through the Traditional Chinese Medicine Systematic Pharmacology Database and Analysis Platform (TCMSP), and the active ingredients of the drug were obtained after oral utilization (OB) and drug-like properties (DL) screening, and the active ingredient target prediction was performed, while the active ingredient targets were retrieved from GeneCards, OMIM, and DisGeNet database to retrieve knee osteoarthritis-related targets. After taking the intersecting targets, a software called cytoscape 3.9.0 was used for mapping, with the goal of constructing a component-target network map, followed by a string database for mapping, with the goal of making a network map of target protein-target protein interactions, and finally, a gene ontology (GO) enrichment analysis and a Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis, this analysis process was performed in the metascape database. Results: A total of 1272 targets related to osteoarthritis of the knee were collected in this study, 89 active ingredients of Qianjin Sanhuang decoction, involving 267 targets, and 121 therapeutic targets involving osteoarthritis of the knee, and the results of GO enrichment analysis showed that it involved the response to inorganic substances, positive regulation of cell migration, response to oxygen content, response to lipopolysaccharide, response to peptides, regulation of cell adhesion, response to extracellular stimuli, negative regulation of cell differentiation, positive regulation of cell death, glandular development, regulation of apoptotic signaling pathways, development of reproductive structures, response to trauma, response to growth factors, regulation of inflammatory response, cellular response to organic recycling compounds, regulation of proteolysis, etc. After KEGG analysis, the results showed that signaling pathways such as AGE-RAGE pathway and HIF-1 pathway were involved. Conclusion: Qianjin Sanhuang decoction can improve the inflammatory response of knee osteoarthritis through potential multi-pathways, multi-targets and multi-pathways, and can have potential therapeutic effects on osteoarthritis.

Antimicrobial and antibiofilm activity of human recombinant H1 histones against bacterial infections.

Histones possess significant antimicrobial potential, yet their activity against biofilms remains underexplored. Moreover, concerns regarding adverse effects limit their clinical implementation. We investigated the antibacterial efficacy of human recombinant histone H1 subtypes against Pseudomonas aeruginosa PAO1, both planktonic and in biofilms. After the in vitro tests, toxicity and efficacy were assessed in a P. aeruginosa PAO1 infection model using Galleria mellonella larvae. Histones were also evaluated in combination with ciprofloxacin (Cpx) and gentamicin (Gm). Our results demonstrate antimicrobial activity of all three histones against P. aeruginosa PAO1, with H1.0 and H1.4 showing efficacy at lower concentrations. The bactericidal effect was associated with a mechanism of membrane disruption. In vitro studies using static and dynamic models showed that H1.4 had antibiofilm potential by reducing cell biomass. Neither H1.0 nor H1.4 showed toxicity in G. mellonella larvae, and both increased larvae survival when infected with P. aeruginosa PAO1. Although in vitro synergism was observed between ciprofloxacin and H1.0, no improvement over the antibiotic alone was noted in vivo. Differences in antibacterial and antibiofilm activity were attributed to sequence and structural variations among histone subtypes. Moreover, the efficacy of H1.0 and H1.4 was influenced by the presence and strength of the extracellular matrix. These findings suggest histones hold promise for combating acute and chronic infections caused by pathogens such as P. aeruginosa.IMPORTANCEThe constant increase of multidrug-resistant bacteria is a critical global concern. The inefficacy of current therapies to treat bacterial infections is attributed to multiple mechanisms of resistance, including the capacity to form biofilms. Therefore, the identification of novel and safe therapeutic strategies is imperative. This study confirms the antimicrobial potential of three histone H1 subtypes against both Gram-negative and Gram-positive bacteria. Furthermore, histones H1.0 and H1.4 demonstrated in vivo efficacy without associated toxicity in an acute infection model of Pseudomonas aeruginosa PAO1 in Galleria mellonella larvae. The bactericidal effect of these proteins also resulted in biomass reduction of P. aeruginosa PAO1 biofilms. Given the clinical significance of this opportunistic pathogen, our research provides a comprehensive initial evaluation of the efficacy, toxicity, and mechanism of action of a potential new therapeutic approach against acute and chronic bacterial infections.

Use of modified human hemangioma tissue cultures and human umbilical vein endothelial cell cultures to gain mechanistic insights into imiquimod treatment for infantile hemangioma.

Infantile hemangiomas (IH) are a common entity encountered by dermatologists, otolaryngologists, and other surgeons. Oral propranolol is a mainstay of treatment for IH and is well-tolerated, though propranolol-refractory IH and other drug-related adverse events are documented and can limit its usage. There are few in vitro testing systems for putative treatment agents. To address this, we modified a tissue culture system for human hemangioma treatment testing to evaluate the treatment impact of the immune modifier, imiquimod. Human umbilical vein endothelial cells (HUVEC) and hemangioma cultures were treated with several concentrations of imiquimod followed by MTT assays, reporter gene assays, PCR, ELISA, and Western blotting for IL-8, VEGF, Cyclin D1, and IFNα and immunohistochemistry for Cyclin D1 and Ki-67. HUVEC showed acute decreases in IL-8, VEGF, and Cyclin D1 promoter activity and increases in IFNα mRNA after imiquimod treatment. Hemangioma samples showed no change in Ki-67 or Cyclin D1 staining after treatment with imiquimod after 27 d, with significantly increased IL-8 and VEGF. From this preliminary analysis, we discerned that hemangioma tissues can be grown in tissue culture and used for drug treatment studies. We also conclude acute and chronic modulation of cell cycle, angiogenesis factors, and immunostimulatory conditions may be associated with imiquimod mechanisms of action in hemangioma involution.

Influence of Magnetic Field on Calcium Carbonate Precipitation: A Critical Review

This review reports a critical study on the effect of magnetic fields on the precipitation process of calcium carbonate scale from hard water. Indeed, the harmful consequences of the water scaling phenomenon urged researchers to find effective solutions. One of the interesting antiscaling processes is the magnetic treatment of water, which triggers a reduction in the precipitation of calcium carbonate on the walls when in contact with hard water. In the present review, we discuss selected examples related to this process in a combined analysis of the latest advances and the mechanism of action of the magnetic field. Despite the diversity of studies investigating this phenomenon, the effectiveness of this treatment remains a controversial issue, and it is not possible to obtain a clear explanation of the phenomenon. This review proposes, finally, interesting hypotheses which can effectively explain the effect of magnetic treatment on the behavior of hard waters and the precipitation of calcium carbonate, which include magnetohydrodynamics and the hydration effect.

The Functional Impact of VX-770 on the Cystic Fibrosis Transmembrane Conductance Regulator Is Enduring and Increases the Constitutive Activity of This Channel in Primary Airway Epithelia Generated from Healthy Donors

VX-770 is a small-molecule CFTR potentiator that is highly efficacious in individuals with cystic fibrosis caused by mutations in CFTR that result in a defect in channel gating. While studies have reported on the mechanism of action of VX-770, there is still more to learn about the impact that it has on CFTR function in various contexts. The aim of the present study was to examine the longevity and stability of the effect of VX-770 on CFTR function in cultured airway epithelia and to measure the consequences of this interaction. The responses to acute and chronic VX-770 exposure were measured in cultures of expanded and re-differentiated primary human nasal epithelial cells. Acute VX-770 exposure resulted in an increase in CFTR-mediated currents in the absence of exogenous compounds that induce the phosphorylation/activation of CFTR, with acute exposure having the same effect as chronic exposure. The functional impact of VX-770 on CFTR was long-lasting in cultured airway epithelia, as they maintained an electrophysiological profile consistent with the saturation of CFTR with VX-770 over time periods of up to 4 days following a short (0.5 min) or low-dose (100 nM) exposure to VX-770 during an analysis in an Ussing chamber. Rinsing the apical surface prior to VX-770 exposure or exposure during the analysis in the Ussing chamber increased the interaction between VX-770 and the CFTR. Importantly, after short, low-dose exposures to VX-770, the CFTR channels in cultured epithelia appeared to remain saturated with VX-770 for extended periods of time, despite the repetitive rinsing of the apical surface. This finding has implications for patients discontinuing the use of VX-770-containing therapies.

Elraglusib induces cytotoxicity via direct microtubule destabilization independently of GSK3 inhibition.

Elraglusib (9-ING-41) is an ATP-competitive inhibitor of glycogen synthase kinase-3 (GSK3) with pre-clinical studies demonstrating broad activity against many tumour types. Promising early-phase clinical trial data led to FDA orphan drug status, and a randomized phase 2 study in combination with cytotoxic chemotherapy in pancreatic cancer has recently completed its recruitment. Similarly, single-agent responses in adult T-cell leukaemia/lymphoma and melanoma, and combination treatment data in several other tumour types have been encouraging. The elraglusib mechanism of action is unknown, but it is unlikely to act through GSK3 inhibition because cytotoxicity is observed below the IC50 for GSK3 and other small molecule GSK3 inhibitors do not produce cytotoxic effects, at least in lymphoma cells. We show here that elraglusib perturbs chromosomal alignment to cause a mitotic arrest in multiple tumour lines. This arrest is caused by direct microtubule depolymerization, which prevents the attachment of kinetochores to microtubules. At clinically relevant doses, these mitotically arrested cells eventually undergo mitotic slippage, leading to gross chromosome missegregation, DNA damage and apoptosis. These effects explain the cytotoxicity of elraglusib because temporarily pausing cell cycle progression with the CDK4/6 inhibitor palbociclib abolishes any drug-induced genotoxicity and apoptosis. In summary, elraglusib acts as a direct microtubule destabilizer both in vitro and across multiple cancer types, resulting in mitotic arrest, DNA damage and apoptosis. These effects likely account for its broad pan-cancer activity, which does not rely upon GSK3 inhibition as they are not replicated by other GSK3 inhibitors.

The TRIKAFTA to treat the Cystic fibrosis

Cystic fibrosis currently has limited treatment options. This review focuses on the therapeutic potential of TRIKAFTA for treating this disease. We have compiled data from the National Institutes of Health (NIH) and analyzed the composition and mechanism of action of TRIKAFTA. Specifically, we examine how TRIKAFTA targets the F508del mutation, a common genetic variant in cystic fibrosis that results in the deletion of three nucleotides, leading to the loss of phenylalanine at position 508 of the CFTR protein. Our findings indicate that the components of TRIKAFTA effectively address this mutation. While this review provides a general research direction, further studies are necessary to fully understand and treat cystic fibrosis.

Targeted hematopoietic stem cell depletion through SCF-blockade

BackgroundHematopoietic stem cell transplantation (HSCT) is a curative treatment for many diverse blood and immune diseases. However, HSCT regimens currently commonly utilize genotoxic chemotherapy and/or total body irradiation (TBI) conditioning which causes significant morbidity and mortality through inducing broad tissue damage triggering infections, graft vs. host disease, infertility, and secondary cancers. We previously demonstrated that targeted monoclonal antibody (mAb)-based HSC depletion with anti(α)-CD117 mAbs could be an effective alternative conditioning approach for HSCT without toxicity in severe combined immunodeficiency (SCID) mouse models, which has prompted parallel clinical αCD117 mAbs to be developed and tested as conditioning agents in clinical trials starting with treatment of patients with SCID. Subsequent efforts have built upon this work to develop various combination approaches, though none are optimal and how any of these mAbs fully function is unknown.MethodsTo improve efficacy of mAb-based conditioning as a stand-alone conditioning approach for all HSCT settings, it is critical to understand the mechanistic action of αCD117 mAbs on HSCs. Here, we compare the antagonistic properties of αCD117 mAb clones including ACK2, 2B8, and 3C11 as well as ACK2 fragments in vitro and in vivo in both SCID and wildtype (WT) mouse models. Further, to augment efficacy, combination regimens were also explored.ResultsWe confirm that only ACK2 inhibits SCF binding fully and prevents HSC proliferation in vitro. Further, we verify that this corresponds to HSC depletion in vivo and donor engraftment post HSCT in SCID mice. We also show that SCF-blocking αCD117 mAb fragment derivatives retain similar HSC depletion capacity with enhanced engraftment post HSCT in SCID settings, but only full αCD117 mAb ACK2 in combination with αCD47 mAb enables enhanced donor HSC engraftment in WT settings, highlighting that the Fc region is not required for single-agent efficacy in SCID settings but is required in immunocompetent settings. This combination was the only non-genotoxic conditioning approach that enabled robust donor engraftment post HSCT in WT mice.ConclusionThese findings shed new insights into the mechanism of αCD117 mAb-mediated HSC depletion. Further, they highlight multiple approaches for efficacy in SCID settings and optimal combinations for WT settings. This work is likely to aid in the development of clinical non-genotoxic HSCT conditioning approaches that could benefit millions of people world-wide.

Elucidation of the Pharmacological Development and Action Mechanism of Remdesivir and Paxlovid in Combatting COVID-19

COVID-19, the disease identified in 2019 as coronavirus disease, stems from an infection by severe acute respiratory syndrome coronavirus 2, or SARS-CoV-2, which possesses a single-stranded RNA genome. Since the onset of the pandemic attributed to COVID-19, a variety of vaccines and antiviral medications have received approval from international regulatory bodies. Two notable antiviral agents, remdesivir and paxlovid, serve as treatments for viral infections. Initially developed to combat Ebola, remdesivir has also demonstrated efficacy against a broad spectrum of coronaviruses (CoV). It is a nucleoside analogue and functions by being incorporated into the RNA chain of the virus and thus induce the early termination of RNA synthesis. Paxlovid comprises two pharmacological agents, nirmatrelvir and ritonavir. The mechanism of nirmatrelvir involves the specific targeting and inhibition of the viral protease’s active site, thereby impeding the viral replication process. By inhibiting the cytochrome CYP3A4 enzyme which metabolites nirmatrelvir, ritonavir acts as a pharmacokinetic enhancer in this combination. The initial section of this review provides a comprehensive analysis of SARS-CoV-2, detailing the mechanisms of its pathogenesis and the subsequent immune responses elicited by the body. Then this article generalizes the history of development, the structure, and the mode of action of remdesivir and paxlovid.

Dihydroberberine alleviates Th17/Treg imbalance in premature ovarian insufficiency mice via inhibiting Rheb/mTOR signaling

BackgroundPremature ovarian insufficiency (POI) is an immune-related condition. Dihydroberberine (dhBBR) plays a regulatory role in maintaining the T-helper 17 (Th17)/regulatory T (Treg) cell balance. This study aimed to explore the action mechanisms of dhBBR on POI.MethodsIn vivo, female BALB/c mice were used as POI models, treated with dhBBR, or injected with recombinant interleukin (rIL)-17 and anti-CD25 monoclonal antibody. Hematoxylin and eosin staining was used to validate the model and assess the therapeutic effects of dhBBR. mRNA expression levels of cytochrome P450 (Cyp)-17a1, Cyp19a1, Cyp11a1, steroidogenic acute regulatory protein, and luteinizing hormone receptor in mouse ovaries were quantified via quantitative polymerase chain reaction (qPCR). Enzyme-linked immunosorbent assay was used to determine the cytokine and sex hormone levels. Immunohistochemical staining for cleaved-caspase 3 and Ki-67 were performed to assess ovarian cell apoptosis and proliferation. Flow cytometry was used to analyze the Th17/Treg cell balance in the ovary and spleen. In vitro cytotoxicity of dhBBR was measured using the cell counting kit-8 assay. GTP-Ras homolog enriched in brain (Rheb) activity was determined via immunofluorescence assay. Co-immunoprecipitation was performed to assess Rheb activity, Th17 or Treg induction, and binding between Rheb and mammalian target of rapamycin (mTOR) after dhBBR treatment. Flow cytometry and qPCR assays were used to verify the effect of dhBBR on CD4 + cell differentiation. Finally, Rheb/mTOR pathway activation was confirmed via western blotting of proteins, including mTOR, p-mTOR, p70S6K, p-p70S6K, 4E-BP1, and p-4E-BP1.ResultsdhBBR improved the ovarian function in a dose-dependent manner. It also decreased ovarian cell apoptosis and increased cell proliferation. It decreased Th1 and Th17 cell proportions but increased Treg cell proportions in the ovaries and spleens of POI model mice. Cell experiments revealed that dhBBR promoted CD4 + cell differentiation into Treg cells. Co-immunoprecipitation revealed Rheb as the dhBBR target that bound to mTOR. However, MHY1485 restored dhBBR-induced changes in forkhead box P3, IL-10, transforming growth factor-β1, IL-17, IL-22, retinoic acid-related orphan receptor-γt and p-mTOR levels in Th17- and Treg-induced CD4 + cells.ConclusionOverall, dhBBR targeted the Rheb/mTOR pathway to promote CD4 + cell differentiation into Treg cells and alleviate POI.