Mechanism Of Action Research Articles

Melasma Management: A Comprehensive Review of Treatment Strategies Including BTX-A.

Botulinum toxin A (BTX-A) is a widely utilized protein derived from the bacterium Clostridium botulinum, known for its effectiveness in treating various medical conditions involving muscle spasticity, involuntary muscle movements, and pain disorders. Beyond its therapeutic applications, BTX-A is also commonly used in cosmetic procedures to address dynamic wrinkles, hyperhidrosis, sebum production, pore size, and overall skin texture. While the use of neurotoxins like BTX-A for treating conditions such as UVB-induced hyperpigmentation, specifically melasma, is an emerging area of interest, it is not yet a widely recognized treatment for this dermatologic condition. This literature review serves to provide a consolidated overview of the current therapeutic implications of BTX-A treatment for melasma and explore its proposed mechanisms of action. This review aims to provide a comprehensive analysis of the current evidence base for the efficacy of BTX-A treatment on melasma. To gain a comprehensive understanding on the current theories regarding BTX-A treatment on melasma, a literature review was conducted on all the available information using PubMed. A combination of keywords was used to maximize the search results, including "botulinum toxin," "melasma," "melanogenesis," "neurotoxin," "cholinergic system," "BTX-A," and "UV-induced melasma." The search was not restricted by date, allowing for the inclusion of articles offering historical context and those providing the most recent findings. Ninety-eight articles were reviewed to provide a consolidated update on the effectiveness of botulinum toxin A in reducing the appearance of melasma and potential mechanisms of action involved in doing so. Melasma is a challenging dermatologic condition due to its chronicity and various intrinsic and extrinsic factors that influence its pathogenesis. While current treatment options for melasma include topical, oral, and light-based therapies, recent studies suggest that BTX-A may hold potential as a viable treatment modality for melasma. Despite the mechanism of action remaining unclear, it is hypothesized that BTX-A inhibition of Ach receptors on melanocytes could play a role in the reduction of melanogenesis. BTX-A treatment in melasma-affected skin demonstrates statistically significant reduction in hyperpigmented lesions associated with melasma.

Quantitative study of competitive and selective immobilization of Pb(II)-Ni(II)-Zn(II)-MB(I) by biogenic monohydrocalcite composite and its potential environmental effects.

The study of the competitive and selective immobilization properties and mechanisms of pollutants immobilized by metastable biogenic monohydrocalcite is of great importance for the assessment of the eco-environmental effects and applications of hydrated calcite at the Earth's poles. Microbial culture technology was used to induce the synthesis of biogenic monohydrocalcite (BMHC), and mineral characterization, batch adsorption experiments and chemical analyses were further used to investigate the sequestration characteristics, mechanism of action, and environmental effects of BMHC on Pb(II)-Ni(II)-Zn(II)-methylene blue (MB) compound pollution. The results show that BMHC is an organic-inorganic mineral composite (about 3.60 % organic matter, Mg/Ca ≈ 0.07). The adsorption and immobilization processes of Pb(II), Ni(II), Zn(II), and MB(I) by BMHC are all better fitted by the pseudo-second-order kinetic equation. The passivation ability of BMHC for contaminants is ranked as Pb(II) ≫ Zn(II) > Ni(II) > MB(I). BMHC exhibits an excellent selective sequestration capacity of Pb(II) (k ≥ 31.89), which is related to the solubility product of the carbonate minerals, the initial concentration of Pb(II), ion exchange and mineral phase transformation. Studies have shown that the synthesis and transformation of monohydrocalcite at the Earth's poles may regulate the biogeochemical cycling of environmental pollutants. The study provides a theoretical basis for the environmental effects and geochemical action of biogenic monohydrocalcite and its applications.

The decline in the clinical relevance of pilocarpine and physostigmine monitored in pharmacology textbooks from 1878 to 2023: nine take-home messages for future (pharmacology) textbook authors.

In a recent study, using hydrogen cyanide as paradigm, we have shown that pharmacological knowledge evolves non-linearly ( https://pubmed.ncbi.nlm.nih.gov/38900251/ ). The aim of this study was to investigate the changes in the presentation of the drugs pilocarpine and physostigmine in textbooks from 1878 to 2023. The categories of structure, molecular mechanism of action, pharmacokinetics, effects, indications, adverse drug reactions, interactions, and contraindications were evaluated. The pharmacological knowledge on the molecular mechanism, chemical structure, and pharmacokinetics of pilocarpine and physostigmine changed the most during the period of 150 years. Until 1944, textbooks did not mention a molecular mechanism of action of pilocarpine and from 1951 onwards they described the activation of muscarinic acetylcholine receptors as the molecular basis of pilocarpine's effect. Until 1944, most textbooks on physostigmine also did not mention the molecular mechanism of action. From 1951 onwards, the reversible inhibition of acetylcholinesterase is mentioned as the mechanism of action of physostigmine. In contrast, in the categories effects, indications, adverse drug reactions, interactions, and contraindications, the detected changes in the pharmacological knowledge presented were comparatively smaller. Older pharmacology textbooks were better than newer ones at discussing changes in knowledge and scientific errors. We noted substantial differences in the presentation of pilocarpine and physostigmine among German and US pharmacology textbooks. We show a decline of the clinical relevance of both drugs and their presentation in pharmacological textbooks with physostigmine being virtually irrelevant. But modern textbooks still discuss physostigmine substantially, fitting to studies on the obsolete drug reserpine ( https://pubmed.ncbi.nlm.nih.gov/38103060/ ). Thus, textbooks often far lag clinical practice. Google Scholar conveys the incorrect impression that physostigmine is clinically more relevant than it is. An exponential decline in prescription numbers is a robust indicator of clinical obsolescence. From our study, we extract nine easily implementable take-home messages for future (pharmacology) textbook authors to ensure that this traditional teaching format will prevail against the competition of allegedly more "modern" teaching media.

Insights into podophyllotoxin lactone features: New cyclolignans as potential dual tubulin-topoisomerase II inhibitors.

Chemomodulation of natural cyclolignans as podophyllotoxin has been a successful approach to obtain semisynthetic bioactive derivates. One example of this approach is the FDA-approved drug etoposide for solid and hematological tumors. It differs from the antimitotic activity of the natural product in its mechanism of action, this drug being a topoisomerase II inhibitor instead of a tubulin antimitotic. Within the molecular requirements for the activity of these compounds, the trans-γ-lactone moiety presented in the parent compound has always been a feature to be explored to chemomodulate its bioactivity. In this study, we have obtained different compounds that comply with the molecular characteristics for antitubulin and antitopoisomerase II activity combined in a single molecule. Furthermore, we explored the influence of the trans-lactone moiety on the final activity, finding that the cis-lactone was also interesting in terms of bioactivity. The best values of cytotoxicity and cell cycle inhibition were obtained for a compound lacking the lactone ring, thus mimicking the podophyllic aldehyde functionalization, a selective antimitotic podophyllotoxin derivate. The analogs with cis-lactone also presented interesting cytotoxic activity. The present study illustrates the potential of the chemomodulation of natural products such as natural cyclolignan podophyllotoxin derivates for the discovery of new antitumor agents.

Praziquantel and factor H recruitment differentially affect the susceptibility of Schistosoma mansoni to complement-mediated damage

BackgroundSchistosomes are highly efficient evaders of human immunity, as evident by their ability to survive in human blood for years. How they protect themselves against the constant attack by a key element of innate immunity, the complement system, has remained unclear. In this study, new light is shed on the interaction between distinct life-cycle stages of Schistosoma mansoni and the human complement system.ResultsWe demonstrate that schistosomula, the young stage assumed immediately after cercaria penetration of the skin, are extremely vulnerable towards complement-mediated killing as only 10-20% survive. The survival rate increases to 70% already within 30 minutes and reaches close to 100% within two hours. Pathway-specific complement inhibitors revealed the alternative pathway of complement activation as the main contributor to killing and damage of the schistosomula. Moreover, the complement regulator factor H is recruited by the schistosomula in this early stage to evade killing. Surviving parasites appear fully viable despite the ongoing complement attack, as demonstrated by the deposition of C3 fragments. However, when exposed to the widely used schistocidal drug praziquantel, the vulnerability of 24 h-old schistosomula towards complement-mediated killing is notably increased; no such effect was observed for mefloquine or oxamniquine. Similar to the younger life-cycle stages, adult worms remain under complement attack. C3 fragments were found all over the outer surface (tegument), deposited mostly on the ridges and not on the tubercles.ConclusionThe recruitment of factor H merits more detailed studies that pinpoint the molecules involved and elucidate the novel possibilities to intercept the uncovered immune evasion therapeutically. That praziquantel and complement work in synergy is surprising and may in the future result in enhanced understanding of the drug’s mechanism of action.

Regenerative capacity of dental mesenchymal stem cells: a systematic review

Background: Oral mesenchymal cells already have wide clinical applications based on their tissue regenerative abilities. The purpose of this study is to present the picture of scientific research on the application of mesenchymal cells. Methods: This review study presents data processing of selected articles on clinical application of oral mesenchymal cells as a future of technology with relatively reduced cost. As inclusion criteria, there are articles that evaluated the regenerative abilities of cells prior to their oral origin. The exclusion criteria are mainly laboratory procedural techniques of manipulation with mesenchymal cells. From 735 articles screened for retrieval, 148 articles were found. After application of exclusion criteria, it was reached in total, about 38 selected articles were analyzed based on combinations of keywords on the PubMed page. These articles were classified based on concrete positive results and evasive results of studies on the role, mechanism of action, and field of application of oral mesenchymal cells. Results: The selection ratio of mesenchymal cells of pulpal origin or of periodontium origin is based on the first type of cells. Regardless of the fact that the trend of their application is again in the oral cavity, in a smaller percentage they tend to be applied for tissue regeneration in other organs. Discussion: There is a lack of “in vivo” type studies. The trend of articles is about review-type studies on the field of application of oral mesenchymal cells. Articles, where the field of application of mesenchymal cells is beyond the oral cavity for the purpose of application in regenerative medicine, occupy a reduced percentage. There are significant differences between differentiating abilities depending on the source from which these cells are taken from the oral cavity. This ability can be modeled by using growth factors, cytokines, bioactive substances, or local anesthetics.

Green Hydrothermal Synthesis of Gallic Acid Carbon Dots: Characterization and Cytotoxic Effects on Colorectal Cancer Cell Line.

Colorectal cancer remains a leading cause of cancer-related deaths worldwide, necessitating the development of novel therapeutic approaches. Carbon dots (CDs) have emerged as promising nanoparticles for biomedical applications due to their unique properties. Gallic acid (GA), a known anticancer agent, is effective against various tumor types. This study explores the potential of gallic acid-derived carbon dots (GA-CDs) as an innovative anticancer agent against HCT-116 colorectal cancer cells, focusing on apoptosis signaling pathways. GA-CDs were synthesized using a one-pot hydrothermal method. Characterization was conducted using transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, and ultraviolet-visible (UV-Vis) absorption spectroscopy. The cytotoxicity of GA and GA-CDs on HCT-116 cells was evaluated using the MTT assay at various concentrations over 24 and 48 hours. Cellular uptake was assessed via fluorescence microscopy, and apoptosis was analyzed using acridine orange/propidium iodide (AO/PI) staining. Total RNA extraction followed by complementary DNA (cDNA) synthesis via RT-PCR was performed, and real time-PCR (Q-PCR) was conducted to examine the expression of apoptosis-related genes Caspase-3, Bax, and Bcl-2. Characterization confirmed the successful synthesis of spherical GA-CDs. GA-CDs exhibited dose- and time-dependent cytotoxicity, with IC50 values of 88.55 µg/mL for GA-CDs and 192.2 µg/mL for GA after 24 hours. Fluorescence microscopy confirmed the efficient uptake of GA-CDs by HCT-116 cells. AO/PI staining showed a significant increase in apoptotic cell numbers after treatment with GA-CDs. Q-PCR analysis revealed overexpression of Caspase-3 and Bax genes in GA-CD-treated cells, though no significant changes were observed in the expression of Bcl-2 or the Bax/Bcl-2 ratio. GA-CDs demonstrated potent anticancer properties by inducing apoptosis and reducing cell viability in HCT-116 cells. These findings suggest the potential of GA-CDs as a novel therapeutic agent for colorectal cancer treatment, warranting further investigation into their mechanism of action and in vivo efficacy.

Fasting as an Adjuvant Therapy for Cancer: Mechanism of Action and Clinical Practice

The fundamental biological characteristics of tumor cells are characterized by irregularities in signaling and metabolic pathways, which are evident through increased glucose uptake, altered mitochondrial function, and the ability to evade growth signals. Interventions such as fasting or fasting-mimicking diets represent a promising strategy that can elicit distinct responses in normal cells compared to tumor cells. These dietary strategies can alter the circulating levels of various hormones and metabolites, including blood glucose, insulin, glucagon, growth hormone, insulin-like growth factor, glucocorticoids, and epinephrine, thereby potentially exerting an anticancer effect. Additionally, elevated levels of insulin-like growth factor-binding proteins and ketone bodies may increase tumor cells’ dependence on their own metabolites, ultimately leading to their apoptosis. The combination of fasting or fasting-mimicking diets with radiotherapy or chemotherapeutic agents has demonstrated enhanced anticancer efficacy. This paper aims to classify fasting, elucidate the mechanisms that underlie its effects, assess its impact on various cancer types, and discuss its clinical applications. We will underscore the differential effects of fasting on normal and cancer cells, the mechanisms responsible for these effects, and the imperative for clinical implementation.

The Present Difficulties and Potential Benefits of Dopaminergic Agents in Parkinson's Disease Treatment

Parkinson's disease (PD) is a progressive neurological condition characterized by bradykinesia, rigidity, tremors, and impaired balance, among other motor impairments. The issue arises from dopaminergic neurons located in the spinal column of the brain. This research report examines the therapeutic potential of dopaminergic medications in the management of Parkinson's disease. The central concept of Parkinson's disease (PD) revolves around the notion that dopaminergic pathways exert significant influence over the regulation of movement. The book examines various dopaminergic medications, elucidating their mechanisms of action and the impact they exert on dopamine signaling. Examples of these medications include levodopa, dopamine agonists, and monoamine oxidase-B (MAO-B) inhibitors. Although dopaminergic medicines initially aid in the treatment of Parkinson's disease (PD), prolonged usage of these medications gives rise to several complications. Experiencing dyskinesias and motor fluctuations, characterized by episodes of involuntary movements and behaviors that are undesired, is a significant challenge. This study investigates the underlying causes of these difficulties and explores potential treatment options, including the use of controlled-release formulations and further therapy. The book discusses the non-motor symptoms of Parkinson's disease (PD), as well as the use of dopaminergic medications to treat mood disorders, autonomic dysfunction, and cognitive loss. Dopaminergic medications remain crucial in reducing motor symptoms and enhancing the quality of life for those with Parkinson's disease. Parkinson's disease (PD) is a complex condition with multiple distinct variations. In order to address its existing challenges and explore its potential implications for future Parkinson's disease medications, a comprehensive and effectively coordinated strategy is required.

Unlocking the Potential of Antimicrobial Maximin Peptides From Bombina maxima Against Staphylococcus aureus: Deciphering Their Mode of Action Through a Mimetic Bacterial Membrane Environment

ABSTRACTAntimicrobial peptides (AMPs) offer a promising strategy to address bacterial resistance by targeting bacterial membranes, bypassing the limitations of receptor site‐based approaches. This study focuses on combating the notorious multidrug resistance of Staphylococcus aureus using AMPs, particularly maximin peptides derived from Bombina maxima. Previous research suggested that maximin peptides could disrupt bacterial membranes among anuran AMPs. This prompted us to screen these maximin peptides to identify those with strong membrane‐targeting abilities against S. aureus. Initially, stability and activity assessments on all 89 peptides involved analyzing hydrogen bond dilution, peptide permeation, and hemolytic activity predictions, leading to the rationalization of four promising candidates: Max_5, Max_13, Max_21, and Max_45. When subjected to membrane simulations, the monomeric state of these peptides displayed partial helix‐coil transitions with significant structural interactions that disrupted the membrane, particularly for Max_5 and Max_13. Additionally, the multimeric states of these two peptides were examined through membrane simulations to elucidate their mechanisms of action. Analyses focusing on membrane thickness, lipid distortions, and curvature revealed that both Max_5 and Max_13 exerted strong membrane‐rupturing effects. These peptides seemed to operate by forming pores, facilitating lipid diffusion, creating cavities, and affecting membrane thickness, which allowed water penetration due to increased membrane fluidity, indicating the barrel‐stave pore model. Despite structural differences between Max_5 and Max_13, both peptides demonstrated similar outcomes, emphasizing their potential for future therapeutic applications. This study highlights the efficacy of computational methods in accelerating the identification of potent antimicrobial peptides, providing a pathway for developing novel antimicrobial therapies.

Inhibition mechanism of potential antituberculosis compound lansoprazole sulfide

Tuberculosis is one of the most common causes of death worldwide, with a rapid emergence of multi-drug-resistant strains underscoring the need for new antituberculosis drugs. Recent studies indicate that lansoprazole-a known gastric proton pump inhibitor and its intracellular metabolite, lansoprazole sulfide (LPZS)-are potential antituberculosis compounds. Yet, their inhibitory mechanism and site of action still remain unknown. Here, we combine biochemical, computational, and structural approaches to probe the interaction of LPZS with the respiratory chain supercomplex III2IV2 of Mycobacterium smegmatis, a close homolog of Mycobacterium tuberculosis supercomplex. We show that LPZS binds to the Qo cavity of the mycobacterial supercomplex, inhibiting the quinol substrate oxidation process and the activity of the enzyme. We solve high-resolution (2.6 Å) cryo-electron microscopy (cryo-EM) structures of the supercomplex with bound LPZS that together with microsecond molecular dynamics simulations, directed mutagenesis, and functional assays reveal key interactions that stabilize the inhibitor, but also how mutations can lead to the emergence of drug resistance. Our combined findings reveal an inhibitory mechanism of LPZS and provide a structural basis for drug development against tuberculosis.

Adeno-Associated Virus-Mediated Dickkopf-1 Gene Transduction Reduces Silica-Induced Oxidative Stress and Silicosis in Mouse Lung.

Aims: Silicosis is a lung disease caused by inhalation of silica particles. Both silica-induced oxidative stress and aberrant activation of the Wnt/β-catenin signaling pathway are potential targets in the treatment of pulmonary fibrosis. Dickkopf-1 (Dkk1), an inhibitor of the Wnt/β-catenin signaling pathway, plays regulatory roles in cell fate determination and immune responses. Our previous study demonstrated that adenoviral vector-mediated Dkk1 gene transfer alleviated the silica-induced mouse silicosis. However, the mechanism of therapeutic action of Dkk1 in silicosis is yet completely understood; together with the drawbacks of adenoviral vectors in gene therapy, we investigated the therapeutic effect and mechanisms of Dkk1 by employing an adeno-associated virus (AAV) vector in a silicosis mouse model. Results: The AAV vector could efficiently transduce the Dkk1 gene in silicotic lung during both the early and the late phases of disease, resulting in an alleviation of silicotic lesions, improvement of pulmonary compliance, and radiological findings. Mechanistic studies further demonstrated that the transduction of Dkk1 inhibited the silica-activated Wnt/β-catenin signaling and reduced the silica-induced reactive oxygen species-producing enzyme NADPH oxidase 4, oxidative stress regulator nuclear factor erythroid 2-related factor 2, and signaling molecules binding immunoglobulin protein and C/EBP homologous protein. In addition, shRNA-mediated downregulation of Dkk1 exacerbated the progression of silicosis in mice, whereas the treatment of ROS scavenger n-acetylcysteine showed a comparable mitigation of silicosis that was seen in the AAV-Dkk1 treatment. Innovation and Conclusion: This study provides an insight into the mechanism by which Dkk1 inhibits the silica-induced Wnt signaling and oxidative stress to mitigate the pathogenesis of lung silicosis and evidence of the potential of AAV-mediated Dkk1 gene transfer as an alternative approach in silicosis treatment. Antioxid. Redox Signal. 00, 000-000.

Abstract 4136621: Efficacy of Empagliflozin in Heart Failure with Preserved Ejection Fraction is related to the presence of echocardiographic features of diastolic dysfunction in the EMPEROR-Preserved trial.

Introduction: Efficacy of SGLT2i empagliflozin in Heart Failure is seen across the LVEF spectrum and in multiple clinical subgroups, with diverse mechanisms of action. We hypothesized that objective echo evidence of diastolic dysfunction (DD) in HFpEF may predict the response to empagliflozin. Methods: We defined DD as the presence of LAVI ≥34 mL/m 2 , E/e ≥13 or LVMi >115 (males) or >95 (females) and created three categories with 0, 1 or ≥2 DD criteria. We report the impact of baseline DD on response to empagliflozin therapy and adverse effects. Analyses were performed using the intention-to-treat principle. For time-to-first-event analyses, differences in treatment effects across the three DD categories were assessed by a Cox proportional hazards model, with pre-specified covariates of age, gender, region, diabetes, LVEF, and eGFR. Total events were assessed using a joint frailty model, with CV death (CVD) as a competing risk. Results: Of 5988 patients in EMPEROR-Preserved 3766 (63%) had no baseline DD, 1619 (27%) one and 603 (10%) ≥2 measures. The percentage of males decreased as DD category increased, 57.2% for none, 54.2% for one and 46.6% for ≥2, p <0.0001. Other demographic features significantly associated with DD categories were race, ethnicity and region and it was more common with age, with lower HR, DBP, body weight and eGFR. DD was more frequent with ischaemic aetiology and higher LVEF, but not with baseline NT−proBNP, DM or COPD. Time to HHF or CVD showed a progressive treatment effect across the three DD categories (interaction p-value 0.0014), with estimated HR’s of 0.91 (none present), 0.64 (1 present) and 0.49 (>=2). A significant treatment-by-subgroup interaction was also observed for the total number of HHF, with estimated HR’s of 0.95 (none present), 0.52 (1 present) and 0.29 (≥2). In the responder analysis, ≥10 point improvement in KCCQ at week 52 showed a treatment induced change that was consistent across DD categories (interaction p-value 0.92). The safety profile was consistent across DD classes. Conclusions: Baseline echocardiographic DD predicted an improved clinical response to Empagliflozin in a graded fashion, suggesting the mode of action may target specific changes in diastolic performance.

Abstract 4136614: The design of novel therapeutics that target the L-type calcium channel to prevent hypertrophic cardiomyopathy

Background: Hypertrophic cardiomyopathy (HCM) is an inherited autosomal dominant disease of the sarcomere. Pathogenic features include ventricular hypertrophy, increased myofilament calcium sensitivity, myocardial fibrosis, and diastolic dysfunction. At the level of the myocyte there is cytoskeletal disarray, hypercontractility and altered mitochondrial function. Mitochondrial dysfunction is considered to be a key driver in HCM pathology. Research question: We previously demonstrated that the L-type Ca 2+ channel plays a role in the development of HCM facilitated by a structural-functional communication with mitochondria that can be regulated via the alpha interaction domain (AID) of the channel. In search of a preventative HCM therapy, we explored the efficacy of amino acid peptide variants that correspond to the AID of the cardiac L-type Ca 2+ channel. Methods and Results: Consistent with in silico predictions , competition binding assays confirmed that 4 variant peptides bound with higher affinity to the beta subunit than the AID peptide. In vitro studies confirmed that 3 of the 4 peptides could decrease the characteristic hypermetabolic state in myocytes isolated from a murine model of human HCM ( cTnI-G203S ). In vivo treatment of cTnI-G203S mice with peptide variants prevented the development of HCM and the development of fibrosis, in the absence of alterations in blood pressure, or kidney and liver function or changes in behaviour. Of note, the peptide variants also significantly improved contractile function. Similar effects were measured in αMHC 403/+ mice expressing the MYH6 mutation. Conclusions: Here we describe a first in class therapy that uniquely targets the L-type Ca 2+ channel to modify mitochondrial function and prevent hypertrophic cardiomyopathy. The peptides may be effective for treatment of HCM broadly because the mechanism of action involves the modification of mitochondrial function and impaired energy metabolism that is a common characteristic and driver of the pathology.

Abstract 4139176: SUMOylation of TP53INP1 Is Involved in miR-30a-5p-Regulated Heart Senescence

Introduction: During natural aging, physiological remodeling of the heart is a critical for the cardiovascular disease and heart failure. miR-30a-5p is related to kidney injury, cancer, and autoimmune diseases. However, whether miR-30a-5p has an effect in cardiac aging has yet to be explored. Hypothesis: This study aimed to characterize the role and mechanism of action of miR-30a-5p in cardiac senescence. Methods: We established miR-30a-5p knockout/overexpressing mouse model. Natural heart aging (18-months-old) and D-galactose-induced aging mouse model were established. The mechanism was explored in D-galactose- or 10-days-cultured cardiomyocytes. Results: miR-30a-5p was downregulated in aged mouse hearts and neonatal rat cardiomyocytes (NRCMs). In vivo, using a combination of echocardiography and different molecular biological approaches, we investigated the role of miR-30a-5p knockout or overexpressed mice on natural- or D-galactose-induced heart aging. In vitro, using RNA-sequence and a series of molecular biology, the mechanism of miR-30a-5p-regulated cardiac senescence was explored in cardiomyocytes. miR-30a-5p knockout mice showed aggravated natural- or D-galactose-induced heart aging compared to wild-type littermate mice, with significantly decreased heart function, increased number of γH2AX-positive cells, reduced telomere length, and upregulated p21 and p53 expression. Cardiac-specific knockdown of miR-30a-5p using adeno-associated virus 9 in D-galactose-induced senescent wild-type mice showed effects similar to those observed in knockout mice. Notably, overexpression of miR-30a-5p in wild-type murine hearts alleviated D-galactose-induced heart senescence by improving heart function, increasing telomere length, decreasing the number of γH2AX-positive cells, and downregulating p53 and p21 expression. This was confirmed in D-galactose-treated or naturally aged NRCMs. Mechanistically, TP53INP1 was identified as a target of miR-30a-5p by mediating the SUMOylation of TP53INP1 and its translocation from the cytoplasm to the nucleus to interact with p53. Further evidence demonstrated that cardiac-specific TP53INP1 deficiency ameliorates miR-30a-5p knockout-aggravated cardiac dysfunction and heart senescence. Conclusions: This study identified miR-30a-5p as a crucial modulator of heart senescence and revealed that the miR-30a-5p–TP53INP1–p53 axis is essential for heart and cardiomyocyte aging.

TIPE2 inhibits melanoma progression through MEK/ERK signaling.

Recent studies have uncovered that TIPE2 is involved in the development of cancer. However, less research has been conducted on the role of TIPE2 in melanoma. Our study aims to elucidate the mechanism of action of TIPE2 in the development of melanoma. We examined TIPE2 expression in paracarcinoma tissue and melanoma tissues and found that TIPE2 expression was downregulated in melanoma tissue compared with paracarcinoma tissue. Overexpression of TIPE2 significantly inhibited the proliferation of melanoma cells in vitro and even inhibited tumor formation in vivo. The CCK8 assay results indicated that TIPE2 overexpression suppressed the proliferation of melanoma cells. The colony-forming ability and wound healing ability of TIPE2-overexpressing melanoma cells were significantly reduced compared with those of control cells. Moreover, immunohistochemistry experiments using a nude mouse tumor model showed consistent results. TIPE2 inhibited the phosphorylation of MEK and ERK. In summary, TIPE2 suppresses the proliferation and migration of melanoma cells by affecting proliferation-related factors and possibly by regulating the MEK/ERK pathway. TIPE2 could be used to inhibit melanoma growth and is a potential drug target for future drug development.

Investigation of the Mechanism of Action of AMPs from Amphibians to Identify Bacterial Protein Targets for Therapeutic Applications

Antimicrobial peptides (AMPs) from amphibians represent a promising source of novel antibacterial agents due to their potent and broad-spectrum antimicrobial activity, which positions them as valid alternatives to conventional antibiotics. This review provides a comprehensive analysis of the mechanisms through which amphibian-derived AMPs exert their effects against bacterial pathogens. We focus on the identification of bacterial protein targets implicated in the action of these peptides and on biological processes altered by the effect of AMPs. By examining recent advances in countering multidrug-resistant bacteria through multi-omics approaches, we elucidate how AMPs interact with bacterial membranes, enter bacterial cells, and target a specific protein. We discuss the implications of these interactions in developing targeted therapies and overcoming antibiotic resistance (ABR). This review aims to integrate the current knowledge on AMPs’ mechanisms, identify gaps in our understanding, and propose future directions for research to harness amphibian AMPs in clinical applications.

CRISPR knockout genome-wide screens identify the HELQ-RAD52 axis in regulating the repair of cisplatin-induced single-stranded DNA gaps.

Treatment with genotoxic agents, such as platinum compounds, is still the mainstay therapeutical approach for the majority of cancers. Our understanding of the mechanisms of action of these drugs is, however, imperfect and continuously evolving. Recent advances highlighted single-stranded DNA (ssDNA) gap accumulation as a potential determinant underlying cisplatin chemosensitivity, at least in some genetic backgrounds, such as BRCA mutations. Cisplatin-induced ssDNA gaps form upon restart of DNA synthesis downstream of cisplatin-induced lesions through repriming catalyzed by the PRIMPOL enzyme. Here, we show that PRIMPOL overexpression in otherwise wild-type cells results in accumulation of cisplatin-induced ssDNA gaps without sensitizing cells to cisplatin, suggesting that ssDNA gap accumulation does not confer cisplatin sensitivity in BRCA-proficient cells. To understand how ssDNA gaps may cause cellular sensitivity, we employed CRISPR-mediated genome-wide genetic screening to identify factors which enable the cytotoxicity of cisplatin-induced ssDNA gaps. We found that the helicase HELQ specifically suppresses cisplatin sensitivity in PRIMPOL-overexpressing cells, and this is associated with reduced ssDNA accumulation. We moreover identify RAD52 as a mediator of this pathway. RAD52 promotes ssDNA gap accumulation through a BRCA-mediated mechanism. Our work identified the HELQ-RAD52-BRCA axis as a regulator of ssDNA gap processing and cisplatin sensitization.

Abstract 4139191: ETX-258 - A GalOmic™ siRNA for the Treatment of Heart Failure Following Myocardial Infarction

Introduction: Heart failure with reduced ejection fraction (HFrEF) remains a significant clinical challenge, evidenced by high hospitalization rates and five-year mortality. Current treatments are limited by side effects, poor patient compliance, and the necessity for gradual drug titration. These challenges highlight the need for new therapies that are both safe and effective in targeting the structural remodeling pivotal to disease progression post-myocardial infarction (MI). e-therapeutics (ETX) uniquely combines computation and RNAi to discover life-transforming medicines. ETX’s RNAi platform, GalOmic™, enables generation of specific, potent, and long-acting siRNA therapies that effectively silence novel gene targets in hepatocytes. This highly specific mechanism of action limits unwanted side effects, positioning it as a promising approach to HFrEF treatment. Methods: Potent siRNAs against a hepatic target with cardioprotective potential were designed in silico. Candidate siRNAs were screened in vitro in HEK293 cells and in vivo in C57BL/6J mice to select the lead GalOmic™ siRNA, ETX-258. MI was induced by ligation of the left anterior descending artery in C57BL/6J mice after which ETX-258 was injected subcutaneously weekly for 6 weeks. Eplerenone, a mineralocorticoid receptor antagonist which is part of the current treatment regimen for HFrEF, was used as a comparator. Cardiac function was assessed by echocardiography at 2-, 4- and 6-weeks post-MI. Cardiac damage and structural remodeling were evaluated using circulating biomarkers of cardiac function and histological assessment. Results: ETX-258 was selected as a highly active siRNA for the treatment of heart failure with a long duration of action. Post-MI treatment with ETX-258 significantly improved key echocardiographic parameters of cardiac function, including ejection fraction and total cardiac output, achieving results comparable to eplerenone. Additionally, both structural cardiac parameters and markers of damage and remodeling showed significant improvements, reaching similar levels in both ETX-258 and eplerenone-treated mice. Conclusions: High unmet need remains for HFrEF patients despite existing therapies. These results highlight the potential of ETX-258 to improve cardiac function and pathogenic structural remodeling post-MI. This, paired with the long duration of action and favorable safety profile of GalOmic™ siRNAs, makes ETX-258 a promising candidate for further clinical development.

Genetic remodeling of soil diazotrophs enables partial replacement of synthetic nitrogen fertilizer with biological nitrogen fixation in maize.

Increasing biological nitrogen (N) fixation (BNF) in maize production could reduce the environmental impacts of N fertilizer use, but reactive N in the rhizosphere of maize limits the BNF process. Using non-transgenic methods, we developed gene-edited strains of Klebsiella variicola (Kv137-2253) and Kosakonia sacchari (Ks6-5687) bacteria optimized for root-associated BNF and ammonium excretion in N-rich conditions. The aim of this research was to elucidate the mechanism of action of these strains. We present evidence from in vitro, in planta and field experiments that confirms that our genetic remodeling strategy derepresses BNF activity in N-rich systems and increases ammonium excretion by orders of magnitude above the respective wildtype strains. BNF is demonstrated in controlled environments by the transfer of labeled 15N2 gas from the rhizosphere to the chlorophyll of inoculated maize plants. This was corroborated in several 15N isotope tracer field experiments where inoculation with the formulated, commercial-grade product derived from the gene-edited strains (PIVOT BIO PROVEN® 40) provided on average 21kg N ha-1 to the plant by the VT-R1 growth stages. Data from small-plot and on-farm trials suggest that this technology can improve crop N status pre-flowering and has potential to mitigate the risk of yield loss associated with a reduction in synthetic N fertilizer inputs.