TOPORS-mediated RAD51 SUMOylation facilitates homologous recombination repair.

Homologous recombination (HR) is critical for error-free repair of DNA double-strand breaks. Chromatin loading of RAD51, a key protein that mediates the recombination, is a crucial step in the execution of the HR repair. Here, we present evidence that SUMOylation of RAD51 is crucial for the RAD51 recruitment to chromatin and HR repair. We found that topoisomerase 1-binding arginine/serine-rich protein (TOPORS) induces the SUMOylation of RAD51 at lysine residues 57 and 70 in response to DNA damaging agents. The SUMOylation was facilitated by an ATM-induced phosphorylation of TOPORS at threonine 515 upon DNA damage. Knockdown of TOPORS or expression of SUMOylation-deficient RAD51 mutants caused reduction in supporting normal RAD51 functions during the HR repair, suggesting the physiological importance of the modification. We found that the SUMOylation-deficient RAD51 reduces the association with its crucial binding partner BRCA2, explaining its deficiency in supporting the HR repair. These findings altogether demonstrate a crucial role for TOPORS-mediated RAD51 SUMOylation in promoting HR repair and genomic maintenance.

Systematic review and meta-analysis of randomization controlled and nonrandomized controlled studies on nurse-led nonpharmacological interventions to improve cognition in people with dementia.

AIMS AND OBJECTIVES: To evaluate nurse-led nonpharmacological interventions for improving cognition in people with dementia. BACKGROUND: Starting in 2006, donepezil was administered worldwide to improve cognition; however, its side effects limited its therapeutic value for long-term use, prompting a need for nonpharmacological interventions to improve cognition. Nurse-led nonpharmacological interventions are especially important because they are effective in terms of resources and costs, reduce patient latency and improve patient safety and satisfaction. METHODS: A systematic review was identified by searching 10 electronic databases. The search period was between 1 January 2007, and 30 September 2021. Languages were limited to English and Korean. The inclusion criteria were studies of nurse-led interventions that evaluated cognition using validated instruments. The exclusion criteria were qualitative research, scale development studies, abstracts and grey literature. Quality appraisal of research was conducted using the Risk of Bias in Nonrandomized Studies of Interventions for quasi-experimental studies and the Risk of Bias 2.0 for randomised controlled studies. This study was conducted in accordance with PRISMA reporting guideline (Appendix S1). The search protocol was registered in the PROSPERO (CRD 42021229358). RESULTS: A total of 24 studies were included in the systematic review, and 15 studies were included in the meta-analysis. Meta-analysis included 8 RCT and 7 quasi-experimental studies. The studies (11 quasi-experimental studies and 9 randomised controlled studies) demonstrated low to moderate quality of evidence for improving the cognition of people with dementia. The meta-analysis showed that nurse-led single nonpharmacological interventions more effectively improved cognition than complex interventions in people with dementia. CONCLUSION: Nurse-led nonpharmacological interventions were effective for improving cognition in people with dementia. RELEVANCE TO CLINICAL PRACTICE: Nurses are qualified professionals with expertise in providing nonpharmacological interventions to improve cognition in people with dementia. Nurse-led nonpharmacological interventions for this purpose should be developed in future research.

Prediction value of the LACE index to identify older adults at high risk for all-cause mortality in South Korea: a nationwide population-based study.

BACKGROUND: As a tool to predict early hospital readmission, little is known about the association between LACE index and all-cause mortality in older adults. We aimed to validate the LACE index to predict all-cause mortality in older adults and also analyzed the LACE index outcome of all-cause mortality depending on the disease and age of the participants. METHODS: We used the National Health Insurance Service (NHIS) cohort, a nationwide claims database of Koreans. We enrolled 7491 patients who were hospitalized at least once between 2003 and 2004, aged ≥65 years as of the year of discharge, and subsequently followed-up until 2015. We estimated the LACE index using the NHI database. The Cox proportional hazards model was used to estimate the hazard ratio (HR) for all-cause mortality. Furthermore, we investigated all-cause mortality according to age and underlying disease when the LACE index was ≥10 and < 10, respectively. RESULTS: In populations over 65 years of age, patients with LACE index ≥10 had significantly higher risks of all-cause mortality than in those with LACE index < 10. (HR, 1.44; 95% confidence interval, 1.35-1.54). For those patients aged 65-74 years, the HR of all-cause mortality was found to be higher in patients with LACE index≥10 than in those with LACE index < 10 in almost all the diseases except CRF and mental illnesses. And those patients aged ≥75 years, the HR of all- cause mortality was found to be higher in patients with LACE index ≥10 than in those with LACE index < 10 in the diseases of pneumonia and MACE. CONCLUSION: This is the first study to validate the predictive power of the LACE index to identify older adults at high risk for all-cause mortality using nationwide cohort data. Our findings have policy implications for selecting or managing patients who need post-discharge management.

Recognition of Targets in SAR Images Based on a WVV Feature Using a Subset of Scattering Centers.

This paper proposes a robust method for feature-based matching with potential for application to synthetic aperture radar (SAR) automatic target recognition (ATR). The scarcity of measured SAR data available for training classification algorithms leads to the replacement of such data with synthetic data. As attributed scattering centers (ASCs) extracted from the SAR image reflect the electromagnetic phenomenon of the SAR target, this is effective for classifying targets when purely synthetic SAR images are used as the template. In the classification stage, following preparation of the extracted template ASC dataset, some of the template ASCs were subsampled by the amplitude and the neighbor matching algorithm to focus on the related points of the test ASCs. Then, the subset of ASCs were reconstructed to the world view vector feature set, considering the point similarity and structure similarity simultaneously. Finally, the matching scores between the two sets were calculated using weighted bipartite graph matching and then combined with several weights for overall similarity. Experiments on synthetic and measured paired labeled experiment datasets, which are publicly available, were conducted to verify the effectiveness and robustness of the proposed method. The proposed method can be used in practical SAR ATR systems trained using simulated images.

Fabrication and Evaluation of Gellan Gum/Hyaluronic Acid Hydrogel for Retinal Tissue Engineering Biomaterial and the Influence of Substrate Stress Relaxation on Retinal Pigment Epithelial Cells.

Cell therapies for age-related macular degeneration (AMD) treatment have been developed by integrating hydrogel-based biomaterials. Until now, cell activity has been observed only in terms of the modulus of the hydrogel. In addition, cell behavior has only been observed in the 2D environment of the hydrogel and the 3D matrix. As time-dependent stress relaxation is considered a significant mechanical cue for the control of cellular activities, it is important to optimize hydrogels for retinal tissue engineering (TE) by applying this viewpoint. Herein, a gellan Gum (GG)/Hyaluronic acid (HA) hydrogel was fabricated using a facile physical crosslinking method. The physicochemical and mechanical properties were controlled by forming a different composition of GG and HA. The characterization was performed by conducting a mass swelling study, a sol fraction study, a weight loss test, a viscosity test, an injection force study, a compression test, and a stress relaxation analysis. The biological activity of the cells encapsulated in 3D constructs was evaluated by conducting a morphological study, a proliferation test, a live/dead analysis, histology, immunofluorescence staining, and a gene expression study to determine the most appropriate material for retinal TE biomaterial. Hydrogels with moderate amounts of HA showed improved physicochemical and mechanical properties suitable for injection into the retina. Moreover, the time-dependent stress relaxation property of the GG/HA hydrogel was enhanced when the appropriate amount of HA was loaded. In addition, the cellular compatibility of the GG/HA hydrogel in in vitro experiments was significantly improved in the fast-relaxing hydrogel. Overall, these results demonstrate the remarkable potential of GG/HA hydrogel as an injectable hydrogel for retinal TE and the importance of the stress relaxation property when designing retinal TE hydrogels. Therefore, we believe that GG/HA hydrogel is a prospective candidate for retinal TE biomaterial.

2-D08 treatment regulates C2C12 myoblast proliferation and differentiation via the Erk1/2 and proteasome signaling pathways.

SUMOylation is one of the post-translational modifications that involves the covalent attachment of the small ubiquitin-like modifier (SUMO) to the substrate. SUMOylation regulates multiple biological processes, including myoblast proliferation, differentiation, and apoptosis. 2-D08 is a synthetically available flavone, which acts as a potent cell-permeable SUMOylation inhibitor. Its mechanism of action involves preventing the transfer of SUMO from the E2 thioester to the substrate without influencing SUMO-activating enzyme E1 (SAE-1/2) or E2 Ubc9-SUMO thioester formation. However, both the effects and mechanisms of 2-D08 on C2C12 myoblast cells remain unclear. In the present study, we found that treatment with 2-D08 inhibits C2C12 cell proliferation and differentiation. We confirmed that 2-D08 significantly hampers the viability of C2C12 cells. Additionally, it inhibited myogenic differentiation, decreasing myosin heavy chain (MHC), MyoD, and myogenin expression. Furthermore, we confirmed that 2-D08-mediated anti-myogenic effects impair myoblast differentiation and myotube formation, reducing the number of MHC-positive C2C12 cells. In addition, we found that 2-D08 induces the activation of ErK1/2 and the degradation of MyoD and myogenin in C2C12 cells. Taken together, these results indicated that 2-D08 treatment results in the deregulated proliferation and differentiation of myoblasts. However, further research is needed to investigate the long-term effects of 2-D08 on skeletal muscles.

Expression of Cyr61 is associated with clinical course in patients with Crohn's disease.

BACKGROUNDS: Cysteine-rich angiogenic inducer 61 (Cyr61) is emerging as an important regulator of tissue homeostasis and wound repair. We aim to explore the colonic mucosal expression of Cyr61 and analyze the association between Cyr61 expression and clinical course in patients with Crohn's disease (CD). METHODS: Endoscopic samples were identified from 83 CD patients with and 372 controls by searching pathological reports. Among them, age- and sex- matched 43 of each group by a propensity score were selected to compare Cyr61 expression by immunohistochemistry (IHC). IHC scores for Cyr61 expression of CD patients were divided into tertiles to evaluate the association with clinical course. We also measured the level of mRNA for Cyr 61 and proinflammatory genes in inflamed and noninflamed colonic mucosal lesions from CD patients. RESULTS: The mean IHC scores for Cyr61 expression was higher in CD patients (86.5) than in controls (46.1, P < 0.001). In CD patients, the mean IHC scores for Cyr61 expression (68.3) was lower in patients with clinical recurrence than in patients without recurrence (92.2, P = 0.01). Cyr61 mRNA levels in inflamed mucosa were twofold higher than those in non-inflamed lesion (P > 0.05) and the mRNA levels of IL-6 and TLR-4 in inflamed mucosa were significantly higher than those in non-inflamed mucosa in CD patients (all P < 0.05). When CD patients were stratified into tertile groups according to IHC scores for Cyr61 expression, clinical recurrence rates tended to be lower in patients with high Cyr61 expression (P for trend = 0.02). Compared with tertile 1 of Cyr61 expression, tertile 3 of Cyr 61 expression was associated with reduced risk of clinical recurrence (OR 0.43, 95% CI 0.20-0.92) after adjustment for age, sex and CD activity index at the time of colonoscopy in CD patients (P = 0.03). CONCLUSIONS: Cyr61 mucosal expression in CD patients was inversely associated with clinical course. Future study need to be considered to evaluate whether Cyr 61 may play a role in activating inflammatory responses and contributing to wound healing and tissue repair in patients with CD.

Optimization of 1,4-bis(arylsulfonamido)naphthalene-N,N'-diacetic acids as inhibitors of Keap1-Nrf2 protein-protein interaction to suppress neuroinflammation.

The protein-protein interaction (PPI) between kelch-like ECH-associated protein 1 (Keap1) and nuclear factor erythroid 2-related factor 2 (Nrf2) is recognized as a promising target for the prevention and treatment of oxidative stress-related inflammatory diseases. Herein, a series of novel 1,4-bis(arylsulfonamido)naphthalene-N,N'-diacetic acid analogs (7p-t and 8c) were designed to further explore the structure-activity relationships of the series. Their activities were measured first with a fluorescence polarization (FP) assay and more potent compounds were further evaluated using a more sensitive time-resolved fluorescence energy transfer (TR-FRET) assay, demonstrating IC50 values between 7.2 and 31.3 nM. In cytotoxicity studies, the naphthalene derivatives did not show noticeable toxicity to human HepG2-C8 and mouse brain BV-2 microglia cells. Among them, compound 7q bearing oxygen-containing fused rings was shown to significantly stimulate the cellular Nrf2 signaling pathway, including activation of antioxidant response element (ARE)-controlled expression of Nrf2 target genes and proteins. More importantly, 7q suppressed up-regulation of several pro-inflammatory cytokines in lipopolysaccharide (LPS)-challenged BV-2 microglial cells, representing a potential therapeutic application for controlling neuroinflammatory disorders.

Design, synthesis, and biological evaluation of potent 1,2,3,4-tetrahydroisoquinoline derivatives as anticancer agents targeting NF-κB signaling pathway.

The multifunctional transcription factor, nuclear factor-κB (NF-κB), is broadly involved in multiple human diseases, such as cancer and chronic inflammation, through abnormal modulations of the NF-κB signaling cascades. In patients with several types of cancer diseases, NF-κB is excessively activated, which could result in the stimulation of proliferation and/or suppression of apoptosis. Herein, we present a new series of 1,2,3,4-tetrahydroisoquinoline derivatives with good anticancer activities against various human cancer cell lines, which are rationally designed based on our novel NF-κB inhibitors. The SAR studies demonstrated that compound 5d with a methoxy group at the R3 position exhibits the most anti-proliferative activity with GI50 values, ranging 1.591 to 2.281 µM. Similar to KL-1156, the compound 5d (HSR1304) blocked NF-κB nuclear translocation step in LPS-stimulated MDA-MB-231 cells, probably leading to cytotoxic potency against tumor cells. Together with known potent NF-κB inhibitors containing diverse core heterocyclic moieties, the 1,2,3,4-tetrahydroisoquinoline derivatives can provide structural diversity, enhancing a potential for the development of a novel class of anticancer drugs.

Discovery of disubstituted xylylene derivatives as small molecule direct inhibitors of Keap1-Nrf2 protein-protein interaction.

The Keap1-Nrf2-ARE system represents a crucial antioxidant defense mechanism that protects cells against reactive oxygen species. Targeting Keap1-Nrf2 protein-protein interaction (PPI) has become a promising drug target for several oxidative stress-related and inflammatory diseases including pulmonary fibrosis, chronic obstructive pulmonary disorder (COPD) and cancer chemoprevention. For the development of a potential therapeutic agent, drug-like properties and potency are important considerations. In this work, we focused on the modification of 4 as a lead through a molecular dissection strategy in an effort to improve its metabolic stability, leading to the discovery of a series of new disubstituted xylylene derivatives. The preliminary SAR of 9a indicated that compound 21a containing S-methylated acetate moieties exhibited comparable potency to the lead compound 4 in a fluorescent polarization assay but with improved metabolic stability in the presence of human liver microsomes.

Discovery of thienothiazolocarboxamide analogues as novel anti-tubercular agent.

In order to identify anti-tubercular agents with a novel scaffold, commercial libraries of small organic compounds were screened against a fluorescent strain of Mycobacterium tuberculosis H37Rv, using a dual phenotypic assay. Compounds were assessed against bacteria replicating in broth medium, as well as inside macrophages, and thienothiazolocarboxamide (TTCA) scaffold was identified as hit in both assays, with submicromolar inhibitory concentrations. Derivatives of TTCA were further synthesized and evaluated for their inhibitory effects on M.tuberculosis H37Rv. In the present study we report the structure-activity relationship of these TTCA derivatives. Compounds 28, 32 and 42 displayed good anti-tubercular activities, as well as favorable ADME and PK properties. Compound 42 exhibited excellent oral bioavailability in mice with high distribution to lungs, within 1 h. It was found to be efficacious in a dose dependent manner in a murine model of M. tuberculosis infection. Hence, compound 42 is now under evaluation as a potential lead candidate for treatment of tuberculosis.

Nrf2 activation through the inhibition of Keap1-Nrf2 protein-protein interaction.

Activation of the transcription factor Nrf2 via the Keap1-Nrf2-ARE signaling system regulates the transcription and subsequent expression of cellular cytoprotective proteins and plays a crucial role in preventing pathological conditions exacerbated by the overproduction of oxidative stress. In addition to electrophilic modulators, direct non-covalent inhibitors that interrupt the Keap1-Nrf2 protein-protein interaction (PPI) leading to Nrf2 activation have attracted a great deal of attention as potential preventive and therapeutic agents for oxidative stress-related diseases. Structural studies of Keap1-binding ligands, development of biochemical and cellular assays, and new structure-based design approaches have facilitated the discovery of small molecule PPI inhibitors. This perspective reviews the Keap1-Nrf2-ARE system, its physiological functions, and the recent progress in the discovery and the potential applications of direct inhibitors of Keap1-Nrf2 PPI.

Development and characterization of a superabsorbing hydrogel film containing Ulmus davidiana var. Japonica root bark and pullulan for skin wound healing.

Ulmus davidiana var. japonica (UD) has widely been used in Korean traditional medicine for the treatment of various types of diseases including inflammation and skin wounds. The UD root bark powders possess gelling activity with an excellent capacity for absorbing water. This distinct property could make the UD root bark powders to be a great material for manufacturing a gel film specifically for the healing of large and highly exudating wounds (e.g., pressure sores and diabetic ulcers). In this research, we separated the UD root bark powder into 4 different samples based on their sizes and then tested their water absorption capacity and flowability. Based on these results, 75-150 µm sized and below 75 µm sized samples of UD root bark powders were chosen, and UD gel films were prepared. The UD gel films showed good thermal stability and mechanically improved properties compared with pullulan only gel film with excellent swelling capacity and favorable skin adhesiveness. Further, in the animal studies with the skin wound mice model, the UD gel films exhibited significant therapeutic effects on accelerating wound closure and dermal regeneration. Overall, this study demonstrated the applicability of UD root bark powders for hydrogel wound dressing materials, and the potential of UD gel films to be superior wound dressings to currently available ones.

Design, synthesis, and evaluation of l-cystine diamides as l-cystine crystallization inhibitors for cystinuria.

To overcome the chemical and metabolic stability issues of l-cystine dimethyl ester (CDME) and l-cystine methyl ester (CME), a series of l-cystine diamides with or without Nα-methylation was designed, synthesized, and evaluated for their inhibitory activity of l-cystine crystallization. l-Cystine diamides 2a-i without Nα-methylation were found to be potent inhibitors of l-cystine crystallization while Nα-methylation of l-cystine diamides resulted in derivatives 3b-i devoid of any inhibitory activity of l-cystine crystallization. Computational modeling indicates that Nα-methylation leads to significant decrease in binding of the l-cystine diamides to l-cystine crystal surface. Among the l-cystine diamides 2a-i, l-cystine bismorpholide (CDMOR, LH707, 2g) and l-cystine bis(N'-methylpiperazide) (CDNMP, LH708, 2h) are the most potent inhibitors of l-cystine crystallization.

Lower expression of endogenous intestinal alkaline phosphatase may predict worse prognosis in patients with Crohn's disease.

BACKGROUNDS: Intestinal alkaline phosphatase (IAP) plays important role in gut homeostasis. We aimed to evaluate the expression of endogenous IAP and to assess the clinical course according to the expression of endogenous IAP in patients with Crohn's disease (CD). METHODS: A total of 32 consecutive patients (14 males) with CD were included in the study. We measured the level of endogenous iAP in inflamed and noninflamed colonic mucosa. To verify the inflammation status, we measured the level of mRNA for IL-6, TNF-α, and TLR-4. We monitored the clinical courses of patients during follow-up after acquisition of biopsy specimens. RESULTS: Median age of patients was 22.5 years (range, 15-49). Median CD activity index (CDAI, range) was 93.7 (22.8~ 154.9). There were colonic involvements in all patients and perianal involvement in 43.8% patients. The mRNA levels of IL-6 (p = 0.005) and TLR-4 (p = 0.013) in inflamed mucosa were significantly higher than those in non-inflamed mucosa. However, there was no difference of expression of TNF-α mRNA (p = 0.345). During a 14-month follow-up (range, 9 months-54 months), there were 19 patients with clinical recurrences. There were 9 patients (9/19, 47.4%) with IAP expression ratio (inflamed to non-inflamed) ≤ 1.0 in patients with clinical recurrence while there was one patient (1/13, 7.7%) with IAP ratio ≤ 1.0 in patients without clinical recurrence (p = 0.024). CONCLUSION: Lower expression of IAP in inflamed mucosa compared to non-inflamed mucosa may be associated with clinical recurrence in patients with CD.

Combined epitaxial self-assembly of block copolymer lamellae on a hexagonal pre-pattern within microgrooves.

The directed self-assembly (DSA) of block copolymers (BCPs) has emerged as an alternative method to replace or complement conventional photolithography as a result of the approximately 10 nm scale of microdomain ordering, the variety of microstructures that can be obtained and its compatibility with current lithographic processes. In DSA, BCP microdomains are controlled via guide patterns and two main techniques are popular: graphoepitaxy and chemoepitaxy assembly. We have demonstrated a simple and feasible technology for a DSA process by combining graphoepitaxy with "inexpensive" chemoepitaxial assembly to improve the alignment of the lamellar microdomains. For chemoepitaxial assembly, the hexagonal surface patterns from cross-linkable, cylinder-forming BCP were used to guide the graphoepitaxial assembly of the overlying BCP lamellar film. When the guiding patterns were prepared on the hexagonal patterns, it was found that the degree of lamellar alignment was significantly improved compared with the lamellar alignment on the homogeneous neutral layers. Simulation results suggested that the underlying hexagonal pattern can assist the lamellar alignment by reducing the large number of orientation states of the lamellar layers. This strategy is applicable to various nanofabrication processes that require a high degree of fidelity in controlling the nanopatterns over large areas with reduced costs.

Pretreatment antimicrobial susceptibility-guided vs. clarithromycin-based triple therapy for Helicobacter pylori eradication in a region with high rates of multiple drug resistance.

OBJECTIVES: Helicobacter pylori eradication rates with clarithromycin-based triple therapy are declining, and an alternative strategy is needed urgently. We sought to compare the efficacy of pretreatment antimicrobial susceptibility-guided vs. clarithromycin-based triple therapy for H. pylori eradication in a region with high rates of multiple drug resistance. METHODS: Consecutive H. pylori-infected patients with gastric epithelial neoplasms were randomized to receive antimicrobial susceptibility-guided therapy or clarithromycin-based triple therapy for 7 days. In patients in whom the infection was not eradicated, antibiotics were given according to an initial antimicrobial susceptibility test as a second-line therapy in both groups. Eradication rates, antibiotics resistance rates, and drug compliance owing to adverse effects were compared between the groups. RESULTS: In total, 114 patients were enrolled, and 112 completed the protocols. Drug compliance and side effects were similar between the groups. The intention-to-treat eradication rates were 94.7% (95% confidence interval (CI)=88.8-100%, 54/57) in the antimicrobial susceptibility-guided group and 71.9% (95% CI=60.2-83.5%, 41/57) in the clarithromycin-based triple therapy group after the initial treatment (P=0.002), whereas the per-protocol (PP) eradication rates were 96.4% (95% CI=91.5-100%, 54/56) in the antimicrobial susceptibility-guided group and 73.2% (95% CI=61.5-84.8%, 41/56) in the clarithromycin-based triple therapy group (P=0.001). In H. pylori with clarithromycin resistance, the eradication failure rate with first-line treatment was lower in the susceptibility-guided therapy group (0%, 0/12) compared with the clarithromycin-based triple therapy group (80.0%, 95% CI=59.7-100%, 12/15) by PP analysis (P<0.001). CONCLUSIONS: Pretreatment antimicrobial susceptibility-guided therapy is more effective than clarithromycin-based triple therapy for H. pylori eradication in a region with high rates of multiple drug resistance.

Vancomycin-lnduced fluorescence and morphological changes in bis(dipeptide)-containing biphenyl supramolecules.

A biphenyl derivative containing two D-Ala-D-Ala moieties was found to form fluorescent nano/microfibers when subjected to self-assembly conditions in aqueous EtOH. Incubation of the nano/microfibers with vancomycin results in the disappearance of the fibers along with a significant decrease in the fluorescence intensity. The detection limit of vancomycin determined by the fluorescence quenching strategy was calculated to be ca. 57 µM. Regeneration of the original fiber structures were obtained in the presence of Ac-Lys(Ac)-D-Ala-D-Ala, a substance known to bind tightly to vancomycin. Other proteins including bovine serum albumin (BSA), casein, elastase, and chymotrypsin were found to cause no morphological and fluorescence changes in the supramolecules. The unique vancomycin-induced phase transition and fluorescence change were not observed with a biphenyl derivative having L-Ala-L-Ala moiety.

Kinetic study and optimization of ginger mediated ochratoxin A reduction: An eco-friendly approach including toxicity evaluation.

Ochratoxin A (OTA) is a toxic secondary metabolite synthesized by certain fungal strains of Penicillium and Aspergillus and is characterized as a Group 2B carcinogen. OTA infiltrates food and feeds through diverse chains, posing health risks to humans and animals. Herein, seven distinct edible plant materials were screened for their OTA reduction activity. Amidst them, ginger juice in aqueous (2.5%, v/v) showed the highest OTA reduction (95.63%), following first-order reaction kinetics (R2 = 0.92) with 0.72 d-1 rate constant. OTA reduction activity of ginger juice was substantially compromised in the presence of salt (> 2.5%) and temperature (> 40 °C). The response surface methodology-based approach employing Box-Behnken experimental design revealed an integrated effect of temperature, pH, and salt concentrations on OTA reduction (27.44-100%) by ginger juice. In addition, heat treatment (100 °C) and dialysis (12-14 kDa cutoff) of ginger juice implied the inclusion of heat-stable small molecules in reducing OTA. Ginger-treated OTA ameliorated hepatocellular carcinoma (HepG2) cell viability and diminished reactive oxygen species (ROS) levels compared to native OTA. In zebrafish embryos, OTA-induced teratogenic effects, diminished hatching (22.91%), and elevated ROS levels leading to embryo mortality (75%), which was significantly reversed by OTA treated with ginger, underscoring the curtailed toxicity of OTA-converted products by ginger.

Structural modification of C2-substituents on 1,4-bis(arylsulfonamido)benzene or naphthalene-N,N'-diacetic acid derivatives as potent inhibitors of the Keap1-Nrf2 protein-protein interaction.

The Keap1-Nrf2-ARE signaling pathway is an attractive therapeutic target for the prevention and treatment of oxidative stress-associated diseases by activating the cellular expression of cytoprotective enzymes and proteins. Small molecule inhibitors can directly disrupt the Keap1-Nrf2 protein-protein interaction (PPI), resulting in elevated levels of Nrf2 protein and subsequent stimulation of related antioxidant responses. Previously, we found that 1,4-bis(arylsulfonamido)benzene or naphthalene-N,N'-diacetic acid derivatives with an ether type C2-substituent on the benzene or naphthalene core exhibited potent inhibitory activities with IC50's in the submicromolar or nanomolar range. We here describe a more detailed structure-activity relationship study around the C2 substituents containing various polar linkers shedding new insight on their binding interactions with the Keap1 Kelch domain. The key observation from our findings is that the substituents at the C2-position of the benzene or naphthalene scaffold impact their inhibitory potencies in biochemical assays as well as activities in cell culture. The biochemical FP and TR-FRET assays revealed that the naphthalene derivatives 17b and 18 with an additional carboxylate at the C2 were the most active inhibitors against Keap1-Nrf2 PPI. In the cell-based assay, the two compounds were shown to be potent Nrf2 activators of the transcription of the Nrf2-dependent genes, such as HMOX2, GSTM3, and NQO1.