BACKGROUNDGinsenoside Rd (GSRd), one of the main active ingredients in traditional Chinese herbal Panax ginseng, has been found to have therapeutic effects on ischemic stroke. However, the molecular mechanisms of GSRd's neuroprotective function remain unclear. Ischemic stroke-induced oxidative stress results in DNA damage, which triggers cell death and contributes to poor prognosis. Oxidative DNA damage is primarily processed by the base excision repair (BER) pathway. Three of the five major DNA glycosylases that initiate the BER pathway in the event of DNA damage from oxidation are the endonuclease VIII-like (NEIL) proteins. This study aimed to investigate the effect of GSRd on the expression of DNA glycosylases NEILs in a rat model of focal cerebral ischemia.

METHODSNEIL expression patterns were evaluated by quantitative real-time polymerase chain reaction in both normal and middle cerebral artery occlusion (MCAO) rat models. Survival rate and Zea-Longa neurological scores were used to assess the effect of GSRd administration on MCAO rats. Mitochondrial DNA (mtDNA) and nuclear DNA (nDNA) damages were evaluated by the way of real-time analysis of mutation frequency. NEIL expressions were measured in both messenger RNA (mRNA) and protein levels by quantitative polymerase chain reaction and Western blotting analysis. Apoptosis level was quantitated by the expression of cleaved caspase-3 and terminal deoxynucleotidyl transferase-mediated dUTP biotin nick end labeling assay.

RESULTSWe found that GSRd administration reduced mtDNA and nDNA damages, which contributed to an improvement in survival rate and neurological function; significantly up-regulated NEIL1 and NEIL3 expressions in both mRNA and protein levels of MCAO rats; and reduced cell apoptosis and the expression of cleaved caspase-3 in rats at 7 days after MCAO.

CONCLUSIONSOur results indicated that the neuroprotective function of GSRd for acute ischemic stroke might be partially explained by the up-regulation of NEIL1 and NEIL3 expressions.

Animals ; Blotting, Western ; Brain Ischemia ; drug therapy ; enzymology ; DNA Damage ; drug effects ; DNA Glycosylases ; genetics ; metabolism ; Ginsenosides ; therapeutic use ; Infarction, Middle Cerebral Artery ; drug therapy ; enzymology ; Male ; N-Glycosyl Hydrolases ; genetics ; metabolism ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo confirm that arsenic (As) induces oxidative DNA damage in phytohemagglutinin (PHA)-stimulated and unstimulated human lymphocytes.

METHODSThe alkaline comet assay combined with specific enzyme (Formamidopyrimidine-DNA glycosylase, FPG) digestion was used to measure As-induced base damage.

RESULTSThe enzyme-sensitive sites were readily detected with the alkaline comet assay after the cells were treated with 10 micromol As for 2 hours. The repair patterns observed for FPG-created DNA single strand breaks (SSBs) in As-treated cells were comparable to those in hydrogen peroxide (H(2)O(2))-treated cells. The enzyme-created SSBs, As-induced base damage, were more significantly revealed in PHA-stimulated lymphocytes. About 63% and 68% of SSBs induced by As and H(2)O(2), respectively, were repaired in PHA-stimulated lymphocytes by 2-hour repair incubation, but about 34% and 43%, respectively, were repaired in unstimulated cells. About 40% and 49% of base damage induced by As and H(2)O(2), respectively, were repaired in PHA-stimulated lymphocytes, but about 19% and 21 %, respectively, were repaired in unstimulated cells.

CONCLUSIONSAs induces oxidative DNA damage in human lymphocytes within micromolar concentrations. Like the damage induced by H(2)O(2), As-induced DNA damage was more slowly repaired in unstimulated lymphocytes.

Adult ; Arsenic ; pharmacology ; DNA Damage ; DNA Repair ; DNA, Single-Stranded ; drug effects ; DNA-Formamidopyrimidine Glycosylase ; Electrophoresis ; methods ; Humans ; Hydrogen Peroxide ; pharmacology ; Lymphocytes ; drug effects ; N-Glycosyl Hydrolases ; Oxidation-Reduction ; Phytohemagglutinins ; pharmacology

Adenosine diphosphate (ADP)-ribosylation is a unique post-translational modification that regulates many biological processes, such as DNA damage repair. During DNA repair, ADP-ribosylation needs to be reversed by ADP-ribosylhydrolases. A group of ADP-ribosylhydrolases have a catalytic domain, namely the macrodomain, which is conserved in evolution from prokaryotes to humans. Not all macrodomains remove ADP-ribosylation. One set of macrodomains loses enzymatic activity and only binds to ADP-ribose (ADPR). Here, we summarize the biological functions of these macrodomains in DNA damage repair and compare the structure of enzymatically active and inactive macrodomains. Moreover, small molecular inhibitors have been developed that target macrodomains to suppress DNA damage repair and tumor growth. Macrodomain proteins are also expressed in pathogens, such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, these domains may not be directly involved in DNA damage repair in the hosts or pathogens. Instead, they play key roles in pathogen replication. Thus, by targeting macrodomains it may be possible to treat pathogen-induced diseases, such as coronavirus disease 2019 (COVID-19).
ADP-Ribosylation ; COVID-19/metabolism* ; DNA Repair/physiology* ; Evolution, Molecular ; Humans ; Models, Biological ; Models, Molecular ; N-Glycosyl Hydrolases/metabolism* ; Poly(ADP-ribose) Polymerases/metabolism* ; Protein Domains ; SARS-CoV-2/pathogenicity*

We evaluated the effect of the conjugate of basic fibroblast growth factor (FGF2) and saporin (FGF2-SAP) on proliferation of cultured keratocytes. Cultured rabbit and human keratocytes were incubated in medium containing 0.01 to 100 nM of chemical conjugate of EGF2 conjugated by disulfide bond to saporin (CCFS1), FGF2 genetically fused to saporin (rFGF2-SAP), FGF2, or saporin for three hours or four days and cell proliferation was quantified four days after the drug treatment. Proliferation of rabbit and human keratocytes was effectively inhibited by three hour and by four day exposure to CCFS1 and rFGF2-SAP in a dose-dependent manner, whereas it was affected minimally by four day exposure to saporin. Their inhibitory effects were detected at concentrations above 0.1 or 1 nM, and were most prominent in serum-stimulated rabbit keratocytes. These results suggest a potential role for FGF2-SAP in limiting proliferation of keratocytes during corneal wound healing.
Animals ; Antineoplastic Agents, Phytogenic/*pharmacology ; Cell Division/drug effects ; Cell Line ; Cells, Cultured ; Corneal Stroma/*cytology/drug effects ; Dose-Response Relationship, Drug ; Fibroblast Growth Factor 2/*pharmacology ; Humans ; Immunotoxins/pharmacology ; *N-Glycosyl Hydrolases ; Plant Proteins/*pharmacology ; Rabbits ; Ribosome Inactivating Proteins, Type 1

Eight saporin peaks were obtained from the purification of seed extracts of Saponaria officinalis L. Saporin peak No. 6 (SAP-6) showed the highest activity in the inhibition of protein synthesis (98%) in an in vitro translation study. An immunotoxin (IT) was prepared from SAP-6 conjugated to a monoclonal anti-CEA antibody 26/5/1 (mab B) using N-succinimidyl pyridyl dithiopropionate (SPDP) and 2-iminothiolane as a cross linker. Under thermal stability study by a DSC (differential scanning calorimetry), the IT showed a denature temperature of 75 degrees C. In in vitro translation studies, the purified IT showed the same activity as SAP-6 at 10(-7) M and 10(-9) M protein concentration at 0, 30 and 60-min incubation effects with mab B and SAP-6 not conjugated at 24-hr incubation periods on human promyelocytic cell line HL 60 and on human colon adenocarcinoma cell lines which were SW 403, LoVo and LS 174 T. SAP-6, mab B and IT had no cytotoxic effect on HL-60. The IT showed a higher cytotoxic effect than SAP-6 in CEA-positive cell lines. The IT demonstrated the highest cytotoxic effect of 51% inhibition of control at 10(-7) M on the LS 174 T.
Antibodies, Monoclonal/*therapeutic use ; Antineoplastic Agents, Phytogenic/administration & dosage/*pharmacology ; Carcinoembryonic Antigen/biosynthesis/*immunology ; Colonic Neoplasms/*pathology/therapy ; Hot Temperature ; Humans ; Immunotoxins/*therapeutic use ; *N-Glycosyl Hydrolases ; Plant Proteins/administration & dosage/*pharmacology ; Ribosome Inactivating Proteins, Type 1 ; Tumor Cells, Cultured/drug effects