A Highly Conserved Region in BRCA2 Suppresses the RAD51-Interaction Activity of BRC Repeats.

Mammary tumors are the most prevalent type of tumors in female dogs. Breast cancer 2, early onset (BRCA2) malignant mutations are associated with tumorigenesis in humans and dogs. BRCA2 plays a pivotal role in homologous recombination repair by recruiting RAD51 recombinase to DNA damage sites to maintain genome stability. To recruit RAD51, BRCA2 must interact with RAD51 via BRC repeats, but the regulation of this interaction has been unclear. In this study, we focused on a highly conserved region (HCR) near BRC repeats. Using co-immunoprecipitation and mammalian two-hybrid assay, we found that HCR suppressed the RAD51-interaction activity of BRC repeats and that substitutions of HCR phosphorylation sites affected it. In canine tumor samples, we found ten mutations, including a novel HCR mutation (I1110M) from canine tumor samples. The effect of four HCR mutations, including I1110M, on the RAD51-interaction activity of BRC repeats was tested. One of the HCR mutations found in canine mammary tumors increased the interaction, but the two mutations found in human breast cancers decreased it. This study suggested that the HCR regulated the RAD51-interacting activity of BRC repeats through HCR phosphorylation and that mutations in HCR may be related to tumorigenesis in both dogs and humans.

Improved effect of fresh ginseng paste (radix ginseng-ziziphus jujube) on hyperuricemia based on network pharmacology and molecular docking.

Background: Hyperuricemia (HUA) is a metabolic disease caused by reduced excretion or increased production of uric acid. This research aims to study the practical components, active targets, and potential mechanism of the "Radix ginseng (RG)-Ziziphus jujube (ZJ)" herb pair through molecular docking, network pharmacology, and animal experiments. Methods: The potential targets of "Radix ginseng (RG)-Ziziphus jujube (ZJ)" herb pair were obtained from the TCMSP database. The therapeutic targets of HUA were acquired from the GendCards, OMIM, PharmGkb, and TTD databases. Protein-protein interaction network (PPI) was constructed in the STRING 11.0 database. The David database was used for enrichment analysis. Molecular Docking was finished by the AutoDock Vina. And we employed Radix ginseng and Ziziphus jujube as raw materials, which would develop a new functional food fresh ginseng paste (FGP) after boiling. In addition, benzbromarone (Ben) (7.8 mg/kg) and allopurinol (All) (5 mg/kg) were used as positive drugs to evaluate the hyperuricemia induced by FGP (400 and 800 mg/kg) potassium oxazine (PO) (100 mg/kg) and hypoxanthine (HX) (500 mg/kg) on mice. Results: The results showed that 25 targets in the "RG-ZJ" herb pair interacted with hyperuricemia. Then protein-protein interaction (PPI) analysis showed that TNF, IL-1ß, and VEGFA were core genes. KEGG enrichment analysis showed that the Toll-like receptor signaling pathway and IL-17 signaling pathway were mainly involved. Meantime, animal experiments showed that FGP could improve the HUA status of mice by reducing serum UA BUN, XO, and liver XO levels (p < 0.05, p < 0.01). Furthermore, we analyzed the main ingredients of FGP by HPLC. We found that the main ingredients of FGP had solid binding activity to the core target of HUA by molecular docking. Conclusion: This study explored the active ingredients and targets of the "RG-ZJ" herb pair on HUA through network pharmacology, molecular docking, and animal experiments. It revealed the improvement of FGP in mice with HUA.

BRCA2 C-Terminal RAD51-Binding Domain Confers Resistance to DNA-Damaging Agents.

Breast cancer type 2 susceptibility (BRCA2) protein is crucial for initiating DNA damage repair after chemotherapy with DNA interstrand crosslinking agents or X-ray irradiation, which induces DNA double-strand breaks. BRCA2 contains a C-terminal RAD51-binding domain (CTRBD) that interacts with RAD51 oligomer-containing nucleofilaments. In this study, we investigated CTRBD expression in cells exposed to X-ray irradiation and mitomycin C treatment. Surprisingly, BRCA2 CTRBD expression in HeLa cells increased their resistance to X-ray irradiation and mitomycin C. Under endogenous BRCA2 depletion using shRNA, the sensitivities of the BRCA2-depleted cells with and without the CTRBD did not significantly differ. Thus, the resistance to X-ray irradiation conferred by an exogenous CTRBD required endogenous BRCA2 expression. BRCA2 CTRBD-expressing cells demonstrated effective RAD51 foci formation and increased homologous recombination efficiency, but not nonhomologous end-joining efficiency. To the best of our knowledge, our study is the first to report the ability of the BRCA2 functional domain to confer resistance to X-ray irradiation and mitomycin C treatment by increased homologous recombination efficiency. Thus, this peptide may be useful for protecting cells against X-ray irradiation or chemotherapeutic agents.

Protective Effect of 20(R)-Ginsenoside Rg3 Against Cisplatin-Induced Renal Toxicity via PI3K/AKT and NF-[Formula: see text]B Signaling Pathways Based on the Premise of Ensuring Anticancer Effect.

Although the protective effect of ginsenoside on cisplatin-induced renal injury has been extensively studied, whether ginsenoside interferes with the antitumor effect of cisplatin has not been confirmed. In this paper, we verified the main molecular mechanism of 20(R)-ginsenoside Rg3 (R-Rg3) antagonizing cisplatin-induced acute kidney injury (AKI) through the combination of in vivo and in vitro models. It is worth mentioning that the two cell models of HK-2 and HepG2 were used simultaneously for the first time to explore the effect of the activation site of tumor-associated protein p53 on apoptosis and tumor suppression. The results showed that a single injection of cisplatin (20 mg/kg) led to weight loss, the kidney index of the mice increased, and creatinine (CRE) and blood urea nitrogen (BUN) levels in mice sharply increased. Continuous administration of R-Rg3 at doses of 10 and 20 mg/kg for 10 days could significantly alleviate this symptom. Similarly, R-Rg3 treatment reduced oxidative stress damage caused by cisplatin. Moreover, R-Rg3 could observably reduce the apoptosis and inflammatory infiltration of renal tubular cells induced by cisplatin. We used western blotting analysis to demonstrate that R-Rg3 restored cisplatin-induced AKI might be related to PI3K/AKT and NF-[Formula: see text]B mediated apoptosis and inflammation pathways. In the meantime, we also verified that R-Rg3 could activate different sites of p53 to control renal cell apoptosis induced by cisplatin without affecting its antitumor effect.

Alleviative effects of 20(R)-Rg3 on HFD/STZ-induced diabetic nephropathy via MAPK/NF-κB signaling pathways in C57BL/6 mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Diabetic nephropathy (DN) is a major complication of diabetes. The kidney disease develops in nearly 20%-40% of type 2 diabetes (T2D) patients. Ginseng is the root of Panax ginseng C. A. Meyer and has been used in prevention and treatment of diseases for more than 2000 years as a traditional oriental medicine. The 20(R)-ginsenoside Rg3, an active saponin isolated from ginseng, can prevent and treat many diseases. The object of this research was to explore the alleviative effects of 20(R)-Rg3 on DN in mice. MATERIALS AND METHODS: The T2D animal model was induced by continuous access to a high fat diet (HFD) combined with a single injection of 100 mg/kg streptozotocin (STZ) in C57BL/6 mice. The mice were treated by oral gavage of the 20(R)-Rg3 (10, 20 mg/kg) for 8 weeks. Functional and histopathological analyses of the kidneys were then performed. Protein expression levels of MAPKs and NF-κB signal pathways in the kidney were evaluated by western blotting. The expressions of HO-1 and NF-κB in the kidney were measured by fluorescent labeling staining. Other assessments including fasting blood glucose (FBG) levels, blood lipids, oxidative indicators, and inflammatory factors were all performed. RESULTS: Abnormally elevated FBG levels were observed in HFD/STZ mice, contributing significantly to the occurrence of DN. Simultaneously, HFD/STZ mice showed the rise of serum total cholesterol (TC), triglyceride (TG), and low-density lipoprotein cholesterol (LDL-C) levels, and the decrease in high density lipoprotein cholesterol (HDL-C). DN was evidenced by the overproduction of malondialdehyde (MDA), decreased levels of superoxide dismutase (SOD) and catalase (CAT) enzymatic activities, high levels of serum blood urea nitrogen (BUN) and creatinine (Cr). Simultaneously, the results of the immunofluorescence assay showed an increased expression level in NF-κB p65 while a decrease in antioxidant enzyme HO-1 was observed. Herein, 20(R)-Rg3 treatment for 8 weeks not only attenuated FBG levels and advanced glycation end products (AGEs) levels but also improved insulin (INS) level, blood lipids, oxidative stress, and renal function by regulating MAPKs and NF-κB signal pathways in DN mice. CONCLUSION: Taken together, the findings from the present study explicitly confirmed that 20(R)-Rg3 exerted ameliorative effects on DN mice via improving anti-oxidative activity and reducing renal inflammation.

Rare Ginsenoside 20(R)-Rg3 Inhibits D-Galactose-Induced Liver and Kidney Injury by Regulating Oxidative Stress-Induced Apoptosis.

Oxidative stress is considered as a major factor in aging and exacerbates aging process through a variety of molecular mechanisms. D-galactose, a normal reducing sugar with high dose can cause the accumulation of reactive oxygen species (ROS) or stimulate free radical production indirectly by the formation of advanced glycation end products in tissues, finally resulting in oxidative stress. 20(R)-ginsenoside Rg3 (20(R)-Rg3), a major and representative component isolated from red ginseng (Panax ginseng C.A Meyer), has been shown to observably have an anti-oxidative effect. We thereby investigated the beneficial effects of 20(R)-Rg3 on D-galactose-induced oxidative stress injury and its underlying mechanisms. Our results showed that continuous injection of D-galactose with 800[Formula: see text]mg/kg/day for 8 weeks increased the levels of alanine aminotransferase (ALT) and blood urea nitrogen (BUN). However, such increases were attenuated by the treatment of 20(R)-Rg3 for 4 weeks. Meanwhile, 20(R)-Rg3 markedly inhibited D-galactose-caused oxidative stress in liver and kidney. The anti-oxidants, including catalase (CAT) and superoxide dismutase (SOD), were elevated in the mice from 20(R)-Rg3-treated group compared with that from D-galactose group. In contrast, a significant decrease in levels of cytochrome P450 E1 (CYP2E1) and the lipid peroxidation product malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE) were observed in the 20(R)-Rg3-treated group. These effects were associated with a significant increase of AGEs. More importantly, 20(R)-Rg3 effectively attenuated D-galactose induced apoptosis in liver and kidney via restoring the upstream PI3K/AKT signaling pathway. Taken together, our study suggests that 20(R)-Rg3 may be a novel and promising anti-oxidative therapeutic agent to prevent aging-related injuries in liver and kidney.

A Pre-post Evaluation of an Ambulatory Nutrition Support Service for Malnourished Patients Post Hospital Discharge: A Pilot Study.

INTRODUCTION: Malnutrition is common among hospitalised patients, with poor follow up of nutrition support post-discharge. Published studies on the efficacy of ambulatory nutrition support (ANS) for malnourished patients post-discharge are scarce. The aims of this study were to evaluate the rate of dietetics follow-up of malnourished patients postdischarge, before (2008) and after (2010) implementation of a new ANS service, and to evaluate nutritional outcomes post-implementation. MATERIALS AND METHODS: Consecutive samples of 261 (2008) and 163 (2010) adult inpatients referred to dietetics and assessed as malnourished using Subjective Global Assessment (SGA) were enrolled. All subjects received inpatient nutrition intervention and dietetic outpatient clinic follow-up appointments. For the 2010 cohort, ANS was initiated to provide telephone follow-up and home visits for patients who failed to attend the outpatient clinic. Subjective Global Assessment, body weight, quality of life (EQ-5D VAS) and handgrip strength were measured at baseline and five months post-discharge. Paired t-test was used to compare pre- and post-intervention results. RESULTS: In 2008, only 15% of patients returned for follow-up with a dietitian within four months post-discharge. After implementation of ANS in 2010, the follow-up rate was 100%. Mean weight improved from 44.0 ± 8.5 kg to 46.3 ± 9.6 kg, EQ-5D VAS from 61.2 ± 19.8 to 71.6 ± 17.4 and handgrip strength from 15.1 ± 7.1 kg force to 17.5 ± 8.5 kg force; P <0.001 for all. Seventy-four percent of patients improved in SGA score. CONCLUSION: Ambulatory nutrition support resulted in significant improvements in followup rate, nutritional status and quality of life of malnourished patients post-discharge.