Enzyme Inhibitors Research Articles

Zinc-Binding Oligonucleotide Backbone Modifications for Targeting a DNA-Processing Metalloenzyme.

A series of chemically-modified oligonucleotides for targeting the DNA repair nuclease SNM1A have been designed and synthesised. Each oligonucleotide contains a modified internucleotide linkage designed to both mimic the native phosphodiester backbone and chelate to the catalytic zinc ion(s) in the SNM1A active site. Dinucleoside phosphoramidites containing urea, squaramide, sulfanylacetamide, and sulfinylacetamide linkages were prepared and employed successfully in solid-phase oligonucleotide synthesis. All the modified oligonucleotides were found to interact with SNM1A in a gel electrophoresis-based assay, demonstrating the first examples of inhibition of DNA damage repair enzymes for many of these groups in oligonucleotides. One strand containing a sulfinylacetamide-linkage was found to have the strongest interaction with SNM1A and was further tested in a real-time fluorescence assay. This allowed an IC50 value of 231 nM to be determined, significantly lower than previously reported substrate-mimics targeting this enzyme. It is expected that these modified oligonucleotides will serve as a scaffold for the future development of fluorescent or biotin-labelled probes for the in vivo study of DNA repair processes.

Evolving the Role of Black Race in Hypertension Therapeutics.

Black race has been used to guide antihypertensive drug selection for Black patients based on predominant between race (same drug) and intra-race (different drugs) BP response patterns. Accordingly, thiazide diuretics and calcium antagonists have been recommended over renin angiotensin system (RAS) inhibitors (angiotensin receptor blockers, angiotensin converting enzyme inhibitors) and beta blockers for Black patients. Current antihypertensive drug prescribing reflects historical guidance as calcium antagonist and thiazide diuretics are prescribed more and RAS blockers less in Black than White patients. Hypertension control rates in Blacks, lag those for Whites despite their greater use of combination drug therapy and lesser use of monotherapy. This is also true across drug regimens containing any of the four recommended classes for initial therapy as well as for evidence-based combination drug therapy (calcium antagonist or thiazide diuretic + RAS blocker) regimens for which there is no known racial disparity in BP response. Current recommendations acknowledge the need for combination drug therapy in most, especially in Black patients. One exemplar comprehensive hypertension control program achieved > 80% control rates in Black and White patients with minimal racial disparity while utilizing a race-agnostic therapeutic algorithm. Black patients manifest robust, if not outsized, BP responses to diet/lifestyle modifications. Importantly, race neither appears to be a necessary nor sufficient consideration for selection of effective drug therapy. Accordingly, we urge the initiation of adequately intense race-agnostic drug therapy coupled with greater emphasis on diet/lifestyle modifications for Black patients as the cornerstone of a race-informed approach to hypertension therapeutics.

Suboptimal monitoring and management in patients with unrecorded stage 3 chronic kidney disease in real-world settings: Insights from REVEAL-CKD.

Clinical practice guidelines for patients with chronic kidney disease (CKD) recommend regular monitoring and management of kidney function and CKD risk factors. However, the majority of patients with stage 3 CKD lack a diagnosis code, and data on the implementation of these recommendations in the real world are limited. To assess the implementation of guideline-directed monitoring and management practices in the real world in patients with stage 3 CKD without a recorded diagnosis code. REVEAL-CKD (NCT04847531) is a multinational, observational study of patients with stage 3 CKD. Eligible patients had ≥2 consecutive estimated glomerular filtration rate (eGFR) measurements indicative of stage 3 CKD recorded >90 and ≤730 days apart, lacked an International Classification of Diseases 9/10 diagnosis code corresponding to CKD any time before and up to 6 months after the second eGFR measurement. Testing of key measures of care quality were assessed. The study included 435,971 patients from 9 countries. In all countries, the prevalence of urinary albumin-creatinine ratio and albuminuria testing was low. Angiotensin-converting enzyme inhibitor, angiotensin receptor blocker and statin prescriptions were highly variable, and sodium-glucose cotransporter-2 inhibitor prescriptions remained below 21%. Blood pressure measurements were recorded in 20.2%-89.9% of patients. Overall, a large proportion of patients with evidence of stage 3 CKD did not receive recommended, guideline-directed monitoring and management. The variability in standard of care among countries demonstrates a clear opportunity to improve monitoring and management of these patients, most likely improving long-term outcomes.

Effects of angiotensin receptor-neprilysin inhibitor on ketone body metabolism in pre-heart failure/heart failure patients

Recently, a mild elevation of the blood ketone levels was found to exert multifaceted cardioprotective effects. To investigate the effect of angiotensin receptor neprilysin inhibitors (ARNIs) on the blood ketone body levels, 46 stable pre-heart failure (HF)/HF patients were studied, including 23 who switched from angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs) to ARNIs (ARNI group) and 23 who continued treatment with ACE inhibitors or ARBs (control group). At baseline, there were no significant differences in the total ketone body (TKB) levels between the two groups. Three months later, the TKB levels in the ARNI group were higher than the baseline values (baseline to 3 months: 71 [51, 122] to 92 [61, 270] μmol/L, P < 0.01). In the control group, no significant change was observed between the baseline and 3 months later. A multiple regression analysis demonstrated that the initiation of ARNI and an increase in the blood non-esterified fatty acid (NEFA) levels at 3 months increased the percentage changes in the TKB levels from baseline to 3 months (%ΔTKB level) (initiation of ARNI: P = 0.017, NEFA level at 3 months: P < 0.001). These results indicate that ARNI administration induces a mild elevation of the blood TKB levels in pre-HF/HF patients.

Efficacy and safety of dual renin-angiotensin system (RAS) blockade for non-elderly diabetic kidney disease patients with preserved eGFR.

Although sodium glucose cotransporter2 inhibitor (SGLT-2I) is widely used in clinical practice, sufficient renin-angiotensin system (RAS) inhibition remains the cornerstone of diabetic kidney disease (DKD) treatment. The aim of this single-center study was to evaluate the efficacy and safety of dual RAS blockade compared with angiotensin-converting enzyme inhibitor (ACEI)/angiotensin II receptor blocker (ARB) monotherapy in non-elderly DKD patients with preserved eGFR (WHO Standard, < 60y). This single-center study was registered in Chinese Clinical Trial Registry (ChiCTR1900024752), and approved by the ethical committee (KY201994). In this study, we recruited non-elderly type 2 diabetes volunteers with initial diagnosis of DKD to receive dual RAS blockade or monotherapy. 150 non-elderly DKD patients with preserved eGFR were recruited. The patients were randomly divided into dual RAS blockade group and monotherapy group. The dual RAS blockade group treatment regimen was an 80mg valsartan plus a 4mg perindopril tert-butylamine per day. At the same time, monotherapy group patients who received the 8mg perindopril tert-butylamine or 160mg valsartan monotherapy. The clinical data of the three groups were compared at baseline and collected during the follow-up period of 12months. The baseline of patients who received dual RAS blockade was similar to that of monotherapy group. After 12months of treatment, the median level of proteinuria in the dual RAS blockade group was significantly lower than that in the monotherapy group. There was no significant difference in the estimated glomerular filtration rate (eGFR) level, potassium, blood pressure and no serious adverse reactions. In non-elderly DKD patients with preserved eGFR, dual RAS blockade is superior to control proteinuria, and does not increase the probability of adverse reactions such as hyperkalemia, hypotension and acute kidney injury in 12months.

Difluorocarbene-Promoted O-O Bond Activation of Peroxy Acids for Electrophilic Carboxylation of Boronic Acids.

In this study, a difluorocarbene-promoted O-O bond activation of peroxy acids is developed through the insertion of difluorocarbene into O-H bond. This activation strategy in synergy with O-B coordination with boronic acids/ester greatly polarizes the O-O bond for in-situ generation of carboxylium species that reacts with the nucleophilic part of boronic acids in a concerted way to produce esters. Good efficiency and functional group tolerance are demonstrated. Application of this method to the functionalization of a boronic acid drug used as HSL enzyme inhibitor produces smoothly the ester derivative. This difluorocarbene-mediated O-O bond activation strategy is conceptually different from traditional radical type methods, and is also complementary to conventional esterification methods with a distinct retro-synthetic disconnection.

Attenuation of adjuvant-induced arthritis with carnosic acid by inhibiting mPGES-1, COX-2, and bone loss in male SD rats

Objective Rheumatoid arthritis (RA), a chronic inflammatory disease, is characterized by joint swelling, cartilage erosion, and bone destruction. This study investigated the therapeutic efficacy of Carnosic acid (CA), a natural compound with anti-inflammatory and antioxidant properties, in an adjuvant-induced arthritis model. Methods Paw swelling and arthritis index were measured. Oxidative stress markers, including lipid peroxidation and antioxidant enzyme levels, were assessed. Synovial tissue was analyzed for pro-inflammatory markers using real-time Q-PCR and Western blotting. The expression of mPGES-1 was determined by Western blotting. Peripheral neuropathic pain was assessed using cold and mechanical allodynia tests. Bone loss was quantitatively assessed through microcomputed tomography (μCT) scanning of femurs and X-ray radiography. Indomethacin-induced gastric ulcers were evaluated. Molecular docking studies were conducted to analyze the binding affinity of CA to mPGES-1. Results The CA treatment not only demonstrated a significant reduction in joint inflammation and paw swelling but also mitigated oxidative stress and improved the antioxidant defence system. CA inhibited microsomal prostaglandin E synthase-1 (mPGES-1) expression and the expression of pro-inflammatory molecules such as inducible nitric oxide synthase (iNOS) and cyclooxygenases-2 (COX-2), thus attenuating the arthritis symptoms without severe gastrointestinal side effects. Additionally, it inhibited the expression of pro-inflammatory molecules such as iNOS and COX-2, contributing to the reduction of arthritis symptoms. Notably, CA treatment prevented the common side effects of traditional RA treatments like corticosteroids and non-steroidal anti-inflammatory drugs (NSAIDs), including weight loss, bone degradation, and gastric ulcers. Conclusions These findings suggest that CA, through specific enzyme inhibition, offers a compelling alternative therapeutic approach for RA. Further research is warranted to explore the potential of CA in other arthritis models and its suitability for human RA treatment.

Antihypertensive drug treatment and the risk for intra-hemodialysis hypotension.

Antihypertensive medications are often prescribed to manage hypertension in hemodialysis (HD) patients, and intradialytic hypotension (IDH) is a common complication in these patients. We investigated the risk of IDH in incident HD patients who initiated treatment with antihypertensive drugs in monotherapy. The study was conducted as an emulation of a randomized clinical trial in 4072 incident HD patients who started anti-hypertensive drug treatment between January 2016 to December 2019. The primary outcome was the occurrence of IDH during HD sessions. The Gener alised Estimating Equation (GEE) analysis was adjusted by inverse probability treatment weighting (IPTW). Calcium channel blocker (CCB) use was associated with an IDH incidence rate of 7.4 events per person-year (95% CI: 6.2-8.6). Compared to CCB use, use of beta and alpha-beta blockers was strongly associated with a higher likelihood of IDH (OR [95% CI] 2.27 [1.50-3.43]). Use of angiotensin converting enzyme (ACE) inhibitors or angiotensin II receptor blockers (OR [95% CI] 1.71 [1.14-2.57]) and diuretics (OR [95% CI] 1.52 [1.07-2.16]) were also associated with higher likelihood of IDH compared to CCB use. The study suggests that using beta and alpha-beta blockers, ACE inhibitors or angiotensin II receptor blockers, and diuretics may increase the risk of IDH in HD patients compared to CCB use.

SLCO1B1 and ABCG2 genotype-informed phenotypes are related to variation in ramipril exposure.

Ramipril is an angiotensin-converting enzyme inhibitor used for hypertension and heart failure management. To date, scarce literature is available on pharmacogenetic associations affecting ramipril. The goal of this study was to investigate the effect of 120 genetic variants in 34 pharmacogenes (i.e., genes encoding for enzymes like CYPs or UGTs and transporters like ABC or SLC) on ramipril pharmacokinetic variability and adverse drug reaction (ADR) incidence. Twenty-nine healthy volunteers who had participated in a single-dose bioequivalence clinical trial of two formulations of ramipril were recruited. A univariate and multivariate analysis searching for associations between genetic variants and ramipril pharmacokinetics was performed. SLCO1B1 and ABCG2 genotype-informed phenotypes strongly predicted ramipril exposure. Volunteers with the SLCO1B1 decreased function (DF) phenotype presented around 1.7-fold higher dose/weight-corrected area under the curve (AUC/DW) than volunteers with the normal function (NF) phenotype (univariate p-value [puv] <0.001, multivariate p-value [pmv] <0.001, β =0.533, R2=0.648). Similarly, volunteers with ABCG2 DF + poor function (PF) phenotypes presented around 1.6-fold higher AUC/DW than those with the NF phenotype (puv=0.011, pmv<0.001, β =0.259, R2=0.648). Our results suggest that SLCO1B1 and ABCG2 are important transporters to ramipril pharmacokinetics, and their genetic variation strongly alters its pharmacokinetics. Further studies are required to confirm these associations and their clinical relevance.

Discontinuation of afterload-reducing drugs decreases left ventricular outflow tract obstruction in hypertrophic obstructive cardiomyopathy

BackgroundHypertrophic cardiomyopathy (HCM), the most common genetic heart disease, is classified into hypertrophic non-obstructive and hypertrophic obstructive cardiomyopathy (HOCM). Patients with HOCM and coexisting heart failure or arterial hypertension are often prescribed afterload-reducing drugs. Although recommended in current guidelines, data on the direct effect of discontinuing afterload-reducing medication are scarce. This study aims to demonstrate the benefit of discontinuing afterload-reducing medication in HOCM patients.MethodsThis monocentric retrospective analysis included 24 patients with HOCM with afterload-reducing medication, including angiotensin-converting enzyme inhibitors, angiotensin-1 receptor blocker and dihydropyridine-calcium channel blocker, at their first outpatient visit. Effects of discontinuing this medication on LVOTO were examined compared to patients with persistent use despite medical advice.Results16 patients discontinued their afterload-reducing drugs, resulting in a significant decrease in median LVOT gradient from 86.5 [60.5–109.3] mmHg to 61.5 [28.3–97.50] mmHg (p = 0.0004). In 6 patients, beta-blocker therapy was initiated simultaneously, or the dose was increased. Regardless, LVOT gradient reduction was also significant in the remaining 10 patients (p = 0.001). The gradient was not changed significantly in the 8 patients continuing their afterload-reducing medication.ConclusionsDiscontinuation of afterload-reducing drugs significantly decreases LVOTO. Our study underscores the significance of abstaining from afterload-reducing drugs in HOCM patients, particularly in patients with concomitant hypertension or heart failure. According to recently published European guidelines, HOCM patients should preferably be treated with beta-blockers or non-dihydropyridine-calcium channel blockers.

Enzyme inhibiting, antibacterial and antioxidant activities of peel, pulp and seed extracts from dau Ha Chau (Baccaurea ramiflora Lour.) fruit of Vietnam

Dau Ha Chau (DHC) was produced by selecting and growing native kinds of Baccaurea ramiflora Lour. in Vietnam, where the fruit is utilized for fresh eating not only due to its distinctive sour-sweet flavor, but also because of its vitamins and minerals for the body. With the aim to enhance the value of this fruit, the peel, pulp, and seed extracts were determined antioxidant, antibacterial and antidiabetic activities. The filtrates from ethanol extract of peel and seed powders and fruit juice from squeezing pulp were evaporated at 58°C to create the extracts. The six methods of TAC, DPPH, ABTS•+, RP, FRAP, and NO• (antioxidant activities), four bacterial strains and two enzymes (associated with type 2 diabetes mellitus) were evaluated. The results showed that the extract of DHC peel exhibited the highest antioxidant activity (EC50 value from the six methods), antibacterial activity (MIC value), enzyme inhibiting activity (IC50 value), total phenolics content and total flavonoids content, at 643.81 µg/mL, 787.42 µg/mL, 651.10 µg/mL, 718.22 µg/mL, 270.38 µg/mL, 662.44 µg/mL, 16 &lt; MIC ≤ 32 mg/mL (against Propionibacterium acnes, Escherichia coli and Bacillus cereus), 32 &lt; MIC ≤ 64 mg/mL (against Staphylococcus aureus), 2780.91 µg/mL (against α-amylase), 541.24 µg/mL (against α-glucosidase), 119.43 mg GAE/g and 207.17 mg QE/g, respectively, whereas the opposite was true for extract of DHC seed. DHC pulp extract came second in all analytical methods. Pearson correlation coefficients with r value (0.63-0.99) showed a reasonably strong relationship between total phenolics and flavonoids contents, and antioxidant and enzyme inhibiting activities. This is the first report on the antioxidant, antibacterial and antidiabetic activities of DHC Ha Chau fruit extracts, which could be developed for medicinal, pharmaceutical, food preservative purposes, or industrial foods in the future.

Productive Growing System of Andrographis paniculata and Inhibitions of Reverse Transcriptase and 3CLpro Enzymes by The Isolated Andrographolide

Productive Growing System of Andrographis paniculata and Inhibitions of Reverse Transcriptase and 3CLpro Enzymes by The Isolated Andrographolide

Superior cuproptotic efficacy of diethyldithiocarbamate-Cu4O3 nanoparticles over diethyldithiocarbamate-Cu2O nanoparticles in metastatic hepatocellular carcinoma

Metastatic hepatocellular carcinoma (HC) is a serious health concern. The stemness of cancer stem cells (CSCs) is a key driver for HC tumorigenesis, apoptotic resistance, and metastasis, and functional mitochondria are critical for its maintenance. Cuproptosis is Cu-dependent non-apoptotic pathway (mitochondrial dysfunction) via inactivating mitochondrial enzymes (pyruvate dehydrogenase “PDH” and succinate dehydrogenase “SDH”). To effectively treat metastatic HC, it is necessary to induce selective cuproptosis (for halting cancer stemness genes) with selective oxidative imbalance (for increasing cell susceptibility to cuproptosis and inducing non-CSCs death). Herein, two types of Cu oxide nanoparticles (Cu4O3 “C(I + II)” NPs and Cu2O “C(I)” NPs) were used in combination with diethyldithiocarbamate (DD, an aldehyde dehydrogenase “ALDH” inhibitor) for comparative anti-HC investigation. DC(I + II) NPs exhibited higher cytotoxicity, mitochondrial membrane potential, and anti-migration impact than DC(I) NPs in the treated human HC cells (HepG2 and/or Huh7). Moreover, DC(I + II) NPs were more effective than DC(I) NPs in the treatment of HC mouse groups. This was mediated via higher selective accumulation of DC(I + II) NPs in only tumor tissues and oxidant activity, causing stronger selective inhibition of mitochondrial enzymes (PDH, SDH, and ALDH2) than DC(I)NPs. This effect resulted in more suppression of tumor and metastasis markers as well as stemness gene expressions in DC(I + II) NPs-treated HC mice. In addition, both nanocomplexes normalized liver function and hematological parameters. The computational analysis found that DC(I + II) showed higher binding affinity to most of the tested enzymes. Accordingly, DC(I + II) NPs represent a highly effective therapeutic formulation compared to DC(I) NPs for metastatic HC.

In vitro larvicidal efficacy of Lantanacamara essential oil and its nanoemulsion and enzyme inhibition kinetics against Anophelesculicifacies

Mosquitoes are important vectors for the transmission of several infectious diseases that lead to huge morbidity and mortality. The exhaustive use of synthetic insecticides has led to widespread resistance and environmental pollution. Using essential oils and nano-emulsions as novel insecticides is a promising alternative approach for controlling vector borne diseases. In the current study, Lantana camara EO and NE were evaluated for their larvicidal and pupicidal activities against Anopheles culicifacies. The inhibitory effect of EO and NE on AChE, NSE (α/β), and GST was also evaluated and compared. GC-MS analysis of oil displayed 61 major peaks. The stable nano-emulsion with an observed hydrodynamic diameter of 147.62 nm was formed using the o/w method. The nano-emulsion exhibited good larvicidal (LC50 50.35 ppm and LC90 222.84 ppm) and pupicidal (LC50 54.82 ppm and LC90 174.58 ppm) activities. Biochemical evaluations revealed that LCEO and LCNE inhibited AChE, NSE (α/β), and GST, displaying LCNE to be a potent binder to AChE and NSE enzyme, whereas LCEO showed higher binding potency towards GST. The nano-emulsion provides us with novel opportunities to target different mosquito enzymes with improved insecticidal efficacy. Due to its natural origin, it can be further developed as a safer and more potent larvicide/insecticide capable of combating emerging insecticide resistance.

Chemical characterization and biological properties of oyster and shiitake mushrooms extracts and their liposomal formulations

In recent years, the production of liposomal formulations using mushroom extracts has gained increasing interest to increase the bioavailability of bioactive compounds in the nutraceutical field. Based on this information, we aimed to determine the antioxidant capacity (by DPPH, ABTS, CUPRAC and FRAP assays) and enzyme inhibition (against cholinesterase, amylase, glucosidase and tyrosinase) activities of alone and liposomal formulations of Pleurotusostreatus (OYE) or Lentinusedodes (SHE) in different extracts solvents which were methanol (MeOH), aqua (Aq), methanol/aqua (MeOH/Aq). The extracts and formulations were chemically characterized using HPLC-DAD. The mean diameter of SL:SHE and SL:OYE (in MeOH/Aq) extended in range between 60 and 165 nm. The entrapment yields of SL:SHE and SL:OYE (in MeOH/Aq) were 63.8% ± 3.7% and 71.2% ± 2.8%, respectively. HPLC-DAD analysis revealed that ferulic and cinnamic acids were main components in the liposomal formulations. Liposomal formulations (in MeOH) showed higher antioxidant activity in the FRAP and CUPRAC assays. SL:SHE (in Aq) showed effective enzyme inhibition activity on acetylcholinesterase, tyrosinase, amylase and glucosidase enzymes. Based on our findings, the liposomal formulations can be a valuable strategy in preparing functional applications with shiitake and oyster mushrooms.

Association between renin-angiotensin antagonism and COVID-19-related mortality in patients with essential hypertension: A single center, retrospective cohort study.

There is conflicting evidence in select mouse models and humans that suggest angiotensin-converting enzyme 2 expression is increased due to treatment with angiotensin converting enzyme inhibitors and angiotensin receptor blockers (ACEI/ARBs). Given the wide range of conditions that these medications treat, further evaluation is necessary to determine safety in the context of COVID-19. We sought to determine the association between use of ACEI/ARBs and COVID-19 severity in patients with essential hypertension. We included 714 patients with essential hypertension diagnosed with COVID-19 and admitted to University of Iowa Healthcare from March 1, 2020 to June 29, 2021. Severity of COVID-19 infection was assessed based on mortality, length of stay in hospital, intensive care unit admission, and use of supplemental oxygen, invasive ventilation, and vasopressors. Multivariable logistic and linear regression analyses were used for binary and continuous outcomes, respectively. Prior exposure to ACEI/ARBs before admission was significantly associated with lower mortality (OR: 0.454, p=.015), shorter length of stay in hospital (p<.001), and decreased adjusted odds of intensive care admission (OR: 0.719; p<.042). The present results suggest that patients with essential hypertension hospitalized with COVID-19 who had a prescription for ACEI/ARBs prior to admission exhibited less severe COVID-19 and lower in-hospital mortality.

Light‐Induced Unlocking Reactivity of Fragments for Fast Target‐Guided Synthesis of Carbonic Anhydrase Inhibitors

We showcase the successful combination of photochemistry and kinetic target‐guided synthesis (KTGS) for rapidly pinpointing enzyme inhibitors. KTGS is a fragment‐based drug discovery (FBDD) methodology in which the biological target (BT) orchestrates the construction of its own ligand from fragments featuring complementary reactive functionalities. Notably, fragments interacting with the protein binding sites leverage their spatial proximity, facilitating a preferential reaction. Consequently, the resulting bivalent ligand exhibits heightened affinity. Within the realm of KTGS strategies, in situ click chemistry stands out as the most widely used to identify potent protein binders. This approach requires significant protein contributions, such as binding interactions and appropriate orientations of fragments, to overcome high activation barriers. This leads to prolonged incubation times and the potential for generating false negatives, thereby limiting this strategy to proteins that are stable enough in buffer. We herein unveil the possibility to integrate photochemistry into the realm of KTGS, accelerating the ligation reaction between fragments to a time scale of minutes. This approach should significantly expand the narrow reactivity window of traditional KTGS reactions, paving the way for the exploration and development of novel photo‐KTGS reactions.

Light-Induced Unlocking Reactivity of Fragments for Fast Target-Guided Synthesis of Carbonic Anhydrase Inhibitors.

We showcase the successful combination of photochemistry and kinetic target-guided synthesis (KTGS) for rapidly pinpointing enzyme inhibitors. KTGS is a fragment-based drug discovery (FBDD) methodology in which the biological target (BT) orchestrates the construction of its own ligand from fragments featuring complementary reactive functionalities. Notably, fragments interacting with the protein binding sites leverage their spatial proximity, facilitating a preferential reaction. Consequently, the resulting bivalent ligand exhibits heightened affinity. Within the realm of KTGS strategies, in situ click chemistry stands out as the most widely used to identify potent protein binders. This approach requires significant protein contributions, such as binding interactions and appropriate orientations of fragments, to overcome high activation barriers. This leads to prolonged incubation times and the potential for generating false negatives, thereby limiting this strategy to proteins that are stable enough in buffer. We herein unveil the possibility to integrate photochemistry into the realm of KTGS, accelerating the ligation reaction between fragments to a time scale of minutes. This approach should significantly expand the narrow reactivity window of traditional KTGS reactions, paving the way for the exploration and development of novel photo-KTGS reactions.

Thymoquinone, artemisinin, and thymol attenuate proliferation of lung cancer cells as Sphingosine kinase 1 inhibitors

Sphingosine-1-phosphate (S1P) formed via catalytic actions of sphingosine kinase 1 (SphK1) behaves as a pro-survival substance and activates downstream target molecules associated with various pathologies, including initiation, inflammation, and progression of cancer. Here, we aimed to investigate the SphK1 inhibitory potentials of thymoquinone (TQ), Artemisinin (AR), and Thymol (TM) for the therapeutic management of lung cancer. We implemented docking, molecular dynamics (MD) simulations, enzyme inhibition assay, and fluorescence measurement studies to estimate binding affinity and SphK1 inhibitory potential of TQ, AR, and TM. We further investigated the anti-cancer potential of these compounds on non–small cell lung cancer (NSCLC) cell lines (H1299 and A549), followed by estimation of mitochondrial ROS, mitochondrial membrane potential depolarization, and cleavage of DNA by comet assay. Enzyme activity and fluorescence binding studies suggest that TQ, AR, and TM significantly inhibit the activity of SphK1 with IC50 values of 35.52 µM, 42.81 µM, and 53.68 µM, respectively, and have an excellent binding affinity. TQ shows cytotoxic effect and anti-proliferative potentials on H1299 and A549 with an IC50 value of 27.96 µM and 54.43 µM, respectively. Detection of mitochondrial ROS and mitochondrial membrane potential depolarization shows promising TQ-induced oxidative stress on H1299 and A549 cell lines. Comet assay shows promising TQ-induced oxidative DNA damage. In conclusion, TQ, AR, and TM act as potential inhibitors for SphK1, with a strong binding affinity. In addition, the cytotoxicity of TQ is linked to oxidative stress due to mitochondrial ROS generation. Overall, our study suggests that TQ is a promising inhibitor of SphK1 targeting lung cancer therapy.

Identification of volatile metabolites produced from levodopa metabolism by different bacteria strains of the gut microbiome

Interspecies pathways in the gut microbiome have been shown to metabolize levodopa, the primary treatment for Parkinson’s disease, and reduce its bioavailability. While the enzymatic reactions have been identified, the ability to establish the resulting macromolecules as biomarkers of microbial metabolism remains technically challenging. In this study, we leveraged an untargeted mass spectrometry-based approach to investigate volatile organic compounds (VOCs) produced during levodopa metabolism by Enterococcus faecalis, Clostridium sporogenes, and Eggerthella lenta. We cultured these organisms with and without their respective bioactive metabolites and detected levodopa-induced shifts in VOC profiles. We then utilized bioinformatics to identify significant differences in 2,6-dimethylpyrazine, 4,6-dimethylpyrimidine, and 4,5-dimethylpyrimidine associated with its biotransformation. Supplementing cultures with inhibitors of levodopa-metabolizing enzymes revealed specific modulation of levodopa-associated diazines, verifying their relationship to its metabolism. Furthermore, functional group analysis depicts strain-specific VOC profiles that reflect interspecies differences in metabolic activity that can be leveraged to assess microbiome functionality in individual patients. Collectively, this work identifies previously uncharacterized metabolites of microbe-mediated levodopa metabolism to determine potential indicators of this activity and further elucidate the metabolic capabilities of different gut bacteria.