RBM14 promotes DNA end resection during homologous recombination repair.

DNA double-strand break (DSB) repair by homologous recombination (HR) is crucial for the maintenance of genome stability and integrity. In this study, we aim to identify novel RNA binding proteins (RBPs) involved in HR repair because little is known about RBP function in HR. For this purpose, we carry out pulldown assays using a synthetic ssDNA/dsDNA structure coated with replication protein A (RPA) to mimic resected DNA, a crucial intermediate in HR-mediated DSB repair. Using this approach, we identify RNA-binding motif protein 14 (RBM14) as a potential binding partner. We further show that RBM14 interacts with an essential HR repair factor, CtIP. RBM14 is crucial for CtIP recruitment to DSB sites and for subsequent RPA coating and RAD51 replacement, facilitating efficient HR repair. Moreover, inhibition of RBM14 expression sensitizes cancer cells to X-ray irradiation. Together, our results demonstrate that RBM14 promotes DNA end resection to ensure HR repair and may serve as a potential target for cancer therapy.

Longevity-Associated Core Gut Microbiota Mining and Effect of Mediated Probiotic Combinations on Aging Mice: Case Study of a Long-Lived Population in Guangxi, China.

With an ageing population, healthy longevity is becoming an important scientific concern. The longevity phenomenon is closely related to the intestinal microflora and is highly complicated; it is challenging to identify and define the core gut microbiota associated with longevity. Therefore, in this study, 16S rRNA sequencing data were obtained from a total of 135 faecal samples collected as part of the latest sampling and pre-collection initiative in the Guangxi longevity area, and weighted gene co-expression network analysis (WGCNA) was used to find a mediumpurple3 network module significantly associated with the Guangxi longevity phenomenon. Five core genera, namely, Alistipes, Bacteroides, Blautia, Lachnospiraceae NK4A136 group, and Lactobacillus, were identified via network analysis and random forest (RF) in this module. Two potential probiotic strains, Lactobacillus fermentum and Bacteroides fragilis, were further isolated and screened from the above five core genera, and then combined and used as an intervention in naturally ageing mice. The results show a change in the key longevity gut microbiota in mice toward a healthy longevity state after the intervention. In addition, the results show that the probiotic combination effectively ameliorated anxiety and necrosis of hippocampal neuronal cells in senescent mice, improving their antioxidant capacity and reducing their inflammation levels. In conclusion, this longer-term study provides a new approach to the search for longevity hub microbiota. These results may also provide an important theoretical reference for the healthification of the intestinal microflora in the general population, and even the remodelling of the structure of the longevity-state intestinal microflora.

Effect of dietary protein content shift on aging in elderly rats by comprehensive quantitative score and metabolomics analysis.

In the protein nutrition strategy of middle-aged and elderly people, some believe that low protein is good for health, while others believe high protein is good for health. Facing the contradictory situation, the following hypothesis is proposed. There is a process of change from lower to higher ratio of protein nutritional requirements that are good for health in the human body after about 50 years of age, and the age at which the switch occurs is around 65 years of age. Hence, in this study, 50, 25-month-old male rats were randomly divided into five groups: Control (basal diet), LP (low-protein diet with a 30% decrease in protein content compared to the basal diet), HP (high-protein diet with a 30% increase in protein content compared to the basal diet), Model 1 (switched from LP to HP feed at week 4), and Model 2 (switched from LP to HP feed at week 7). After a total of 10 weeks intervention, the liver and serum samples were examined for aging-related indicators, and a newly comprehensive quantitative score was generated using principal component analysis (PCA). The effects of the five protein nutritional modalities were quantified in descending order: Model 1 > HP > LP > Control > Model 2. Furthermore, the differential metabolites in serum and feces were determined by orthogonal partial least squares discriminant analysis, and 15 differential metabolites, significantly associated with protein intake, were identified by Spearman's correlation analysis (p < 0.05). Among the fecal metabolites, 10 were positively correlated and 3 were negatively correlated. In the serum, tyrosine and lactate levels were positively correlated, and acetate levels were negatively correlated. MetaboAnalyst analysis identified that the metabolic pathways influenced by protein intake were mainly related to amino acid and carbohydrate metabolism. The results of metabolomic analysis elucidate the mechanisms underlying the preceding effects to some degree. These efforts not only contribute to a unified protein nutrition strategy but also positively impact the building of a wiser approach to protein nutrition, thereby helping middle-aged and older populations achieve healthy aging.

Study on the antigens and antibodies of Mur and Mia blood groups in southern China.

BACKGROUND: The frequency of Mur and Mia blood group antigens in Asian population is much higher than that in Caucasian population. However, due to the scarcity and high price of commercial detection reagents, there are few studies on antigen and antibody detection and comparative analysis in large samples. OBJECTIVE: To study the occurrence frequency, antigen correlation and antibody properties of Mur and Mia antigens and their corresponding antibodies in southern China. METHODS: Mur and Mia antigens and antibodies in local blood donors and patients were detected by routine serological microplate method. Statistical methods were used to calculate the incidence of two antigens and antibodies and analyze their correlation. RESULTS: Among blood donors, the positive rates of Mur and Mia antigens were 6.4 % and 6.5 % respectively, with no significant difference (P > 0.05). In this region, the incidence of anti-"Mur" and anti-"Mia" was 0.65 % and 0.45 % respectively. But significant difference existed between blood donors and patients (P < 0.05). Among the anti-"Mur" and anti-"Mia" positive patients, most of the antibodies were IgM or IgM + IgG mixed type and had saline activity. CONCLUSION: Mur and Mia antigens and their corresponding antibodies have a high frequency in the population of southern China. In the routine clinical detection of irregular antibodies, Mur or Mia positive (GP.Mur) should be added to screen erythrocytes. Moreover, given the high correlation between Mur and Mia antigens expression on red blood cells, using monoclonal antibodies against Mia could predict the presence of Mur antigen.

Molecular genetic analysis of Mia -positive hybrid glycophorins revealed two novel alleles of GP.Vw and multiple variant transcripts of GYPB existing in both the homozygous GP.Mur and wild-type GPB individuals.

BACKGROUND: The hybrid glycophorins of MNS blood group system express a series of low incidence antigens including Mia , which are commonly found in Southeast Asian populations. In this study, the molecular basis of Mia -positive hybrid glycophorins was firstly clarified in the Chinese Southern Han population. RNA transcripts of GYPB gene in the homozygous GP.Mur individuals were also analyzed. STUDY DESIGN AND METHODS: DNAs were extracted from the whole blood samples of 111 Mia -positive donors. Then, high-resolution melting (HRM) analysis for GYP(B-A-B) was used to analyze the genotypes. Sequencing of GYPB pseudoexon 3 was conducted in the samples with variant melting curves. TA-cloning and subsequent sequencing of GYPA exons 2-4 were performed in the Mia -positive samples with normal GYPB/GYPB genotype by HRM. The transcript analysis of GYPB was conducted in homozygous GP.Mur and wild-type glycophorin B (GPB) individuals using RNA extracted from the cultured erythroblast. RESULTS: The heterozygous GYP*Mur/GYPB (n = 101), homozygous GYP*Mur/GYP*Mur (n = 7) including one novel GYP*Mur allele with an extra GYPA/GYPE specific nucleotide substitution (c.229+110A>T), heterozygous GYP*Bun/GYPB (n = 1) and GYP*Vw/GYPA (n = 2) with two novel GYP*Vw alleles were identified. RNA transcript analysis revealed multiple transcripts of GYPB existing in both homozygous GP.Mur and normal GPB individuals. CONCLUSION: The results showed the genetic diversity of hybrid glycophorins in the Chinese population. Besides, the successful analysis of GYPB transcripts indicates that the cultured erythroblast is a good source for RNA transcript analysis for the protein only expressed on the red blood cells.

TLR4 polymorphisms may increase susceptibility to periodontitis in Pg-positive individuals.

OBJECTIVE: To investigate the correlation between the single nucleotide polymorphisms (SNPs) in the toll-like receptor 4 (TLR4) gene and the susceptibility to chronic periodontitis. DESIGN: 241 Chinese subjects from the cohort of Beijing Shijingshan Community were recruited. Buccal swab samples, the whole unstimulated saliva and periodontal clinical parameters were collected. Human DNA extracted from buccal swab samples were used for genotyping eight SNPs of the TLR4 gene (rs11536889, rs1927906, rs1927911, rs2149356, rs4986790, rs4986791, rs2737190, rs787384) by the Sequenom MassARRAY system. Porphyromonas gingivalis (P. gingivalis) was detected from the deposition of the whole unstimulated saliva through polymerase chain reaction (PCR) method based on 16S rRNA. The correlation between SNPs of TLR4 and chronic periodontitis susceptibility in the whole subjects and the patients detected with P. gingivalis was investigated. RESULTS: The variants of rs4986790 and rs4986791 were not found in 241 Chinese subjects. Moreover, there was no significant difference in the distribution of theother6 SNPs of TLR4 between groups of none/mild -periodontitis and moderate/severe-periodontitis subjects. When combined with P. gingivalis infection, rs1927911 (TT/CC+CT), rs2149356 (TT/GG+GT) and rs2737190 (GG/AA+AG) were independent risk factors of chronic periodontitis. CONCLUSION: Three SNPs of TLR4, i.e., rs1927911 (TT/CC+CT), rs2149356 (TT/GG+GT) and rs2737190 (GG/AA+AG), were associated with moderate/severe chronic periodontitis in Chinese population infected with P. gingivalis. P. gingivalis, which interacted with TLR4 gene plays an important role in the pathogenesis of periodontitis.

[Detection of periodontal pathogens from saliva of type 2 diabetic patients in urban area of Beijing].

OBJECTIVE: To investigate the prevalence of periodontal pathogens from saliva of patients with type 2 diabetes mellitus (T2DM), and to characterize the association between the glucose status and periodontal pathogens in oral cavity. METHODS: All the subjects were hypertension patients under regular care at Beijing hypertension prevention and management institute. Whole unstimulated saliva samples were collected from 45 non-diabetic subjects (non-DM group), 80 well-controlled diabetic patients (DM-well group) and 100 poor-controlled diabetic patients (DM-poor group). DNA was extracted from the salivary deposition, Porphyromonas gingivalis (Pg), Tannerella forsythia (Tf) and Treponema denticola (Td) were detected by polymerase chain reaction (PCR) method based on 16SrRNA. Prevalence and quantity of the pathogens under different glucose states were compared and logistic regression model was set to analyze the factors related to each bacterium. RESULTS: The prevalence of Tf in DM-well group and DM-poor group was significantly lower than that of non-DM group [81% (65/80), 80% (80/100) vs 91% (41/45), P = 0.048], meanwhile the quantity of Tf was also lower than that of non-DM group [1.9(2.6), 2.1(5.3) vs 3.4(6.4)] (P > 0.05). With the worsening of glucose control, the quantity of Tf was declining (P = 0.032). However, the prevalence and the quantity of Pg, Td in 3 groups had no statistical differences (P > 0.05). After adjusting age, gender, number of missing teeth and other periodontal parameters, OR of having Tf in saliva from DM-well group and DM-poor group was 0.58 and 0.53, respectively. CONCLUSIONS: Abnormal blood glucose state may affect the colonization of Tf in oral cavity.