Similarity of Chinese and Pakistani oral microbiome.

Oral microbiota is vital for human health and can be affected by various factors (i.e. diets, ethnicity). However, few studies have compared oral microbiota of individuals from different nationalities in the same environment. Here, we explored the assembly and interaction of oral microbial communities of Chinese and Pakistanis in one university. Firmicutes and Proteobacteria were the predominant microorganisms in the oral cavity of Chinese and Pakistanis. Streptococcus and Neisseria were the dominant genera of China, while Streptococcus and Haemophilus were the dominant genera of Pakistanis. In addition, the oral community membership and structure were not influenced by season, Chinese/Pakistani student and gender, reflecting the stability of the human oral microbiome. The beta diversity of oral microbiomes between Chinese and Pakistanis significantly differed in winter, but not in spring. The alpha diversity of Chinese students and Pakistani students was similar. Moreover, oral microbial community of both Chinese and Pakistani students was mainly driven by stochastic processes. The microbial network of Chinese was more complexity and stability than that of Pakistanis. Our study uncovers the characteristics of human oral microbiota, which is of great significance for oral and human health.

Efficacy and safety of the integration of traditional Chinese medicine and western medicine in the treatment of diabetes-associated cognitive decline: a systematic review and meta-analysis.

Objective: In order to offer possible therapeutic treatment evidence for diabetes-associated cognitive decline (DACD), we thoroughly evaluated the effectiveness and safety of combining Traditional Chinese Medicine (TCM) and Western Medicine (WM) in the current study. Methods: The present study employed a comprehensive search strategy across multiple databases, namely, PubMed, EMBASE, Web of Science, the Cochrane Library, China National Knowledge Infrastructure (CNKI), Wanfang Data, Chinese Scientific Journals Database (VIP), and Chinese Biomedical Literature Database (CBM), to identify relevant articles published until July 2023. Subsequently, a systematic review and meta-analysis of randomized controlled trials (RCTs) were conducted to assess the efficacy and safety of integrating TCM with WM for the treatment of DACD. The literature included in this study was assessed using the GRADE criteria and the Cochrane Handbook for Systematic Reviews of Interventions. Statistical analysis was conducted using RevMan 5.4 software. Results: A total of 20 RCTs involving 1,570 patients were ultimately included in this meta-analysis. The pooled results demonstrated that the integration of TCM and WM therapy significantly enhanced the overall effectiveness rate compared to WM therapy alone [OR = 4.94, 95% CI (3.56, 6.85), p < 0.00001]. Additionally, the combination therapy resulted in reductions in fasting blood glucose [MD = -0.30, 95% CI (-0.49, -0.10), p = 0.003], HbA1c [MD = -0.71, 95%CI (-1.03, -0.40), p < 0.00001], TNF-α levels [MD = -8.28, 95%CI (-13.12, -3.44), p = 0.0008], and TCM Syndrome Score [MD = -5.97, 95%CI (-9.06, -2.88), p = 0.0002]. Meanwhile, the combination therapy had a positive effect on MoCA Score [MD = 2.52, 95% CI (1.75, 3.30), p < 0.00001], and MMSE Score [MD = 2.31, 95% CI (1.33, 3.29), p < 0.00001]. In addition, the safety of the combination therapy was comparable to that of the WM alone [OR = 0.40, 95% CI (0.12, 1.31), p = 0.13]. Conclusion: The integration of TCM and WM therapy outperformed WM alone in DACD treatment. Simultaneously, the combination therapy could improve the therapeutic effect on blood glucose, cognitive function, and inflammation to a certain extent with few adverse effects. However, given the constraints imposed by the quality limitations of the incorporated studies, as well as the potential presence of reporting bias, it is imperative that our findings be substantiated through rigorous, large-scale, randomized controlled trials of superior quality in the future.

Distinct circulating cytokine/chemokine profiles correlate with clinical benefit of immune checkpoint inhibitor monotherapy and combination therapy in advanced non-small cell lung cancer.

BACKGROUND: An ever-increasing number of efforts are focused on identifying effective biomarkers for immune checkpoint inhibitors (ICIs). Cytokines and chemokines are critical to tumor growth, metastasis, tumor angiogenesis, and the immune response against tumor cells. In the study here, we determined the correlation between circulating cytokines/chemokines and the clinical benefit of ICIs for non-small cell lung cancer (NSCLC) patients. METHODS: Peripheral blood samples were collected before and during treatment (at 12th week). Plasma levels of cytokines/chemokines and specific stress response markers were measured using the Bio-Plex Pro Human Cytokines Grp I Panel (27-plex), an APEX1 detection kit, and a human LAP(TGF-ß1) immunoassay kit. A Mann-Whitney U-test or Wilcoxon signed-rank test and a Cox proportional hazards model were employed for statistical analysis. RESULTS: In the ICI monotherapy cohort, a high level of IL-6 at pretreatment or an elevation of IL-6, IL-8, FGF2, CXCL10, CCR1, PDFGB, TNF, and APEX1 posttreatment was associated with poor progress-free survival (PFS). A posttreatment elevation (defined herein as change rate) of CXCL10 was also associated with poor overall survival (OS). In the combinational therapy group, a high level of IL-12, IL-17A, FGF2, VEGF, and APEX1 at pretreatment and an elevation of CCL2 posttreatment were associated with poor PFS. A high level of IL-9, FGF2, PDFGB, CCL4, TFGB, and APEX1 at pretreatment and an elevation of IL-13, CSF2, and CCL2 at posttreatment were associated with poor OS of patients receiving combination therapy. CONCLUSIONS: The study here suggests that circulating cytokines/chemokines are feasible, noninvasive biomarkers for predicting clinical benefit of ICI treatment for NSCLC. Distinct circulating factor profiles were observed in individuals receiving ICI monotherapy or combination therapy.

Molecular Detection and Genetic Characterization of Japanese Encephalitis Virus in Animals from 11 Provinces in China.

Japanese encephalitis virus (JEV), which uses a mosquito primary vector and swine as a reservoir host, poses a significant risk to human and animal health. JEV can be detected in cattle, goats and dogs. A molecular epidemiological survey of JEV was conducted in 3105 mammals from five species, swine, fox, racoon dog, yak and goat, and 17,300 mosquitoes from 11 Chinese provinces. JEV was detected in pigs from Heilongjiang (12/328, 3.66%), Jilin (17/642, 2.65%), Shandong (14/832, 1.68%), Guangxi (8/278, 2.88%) and Inner Mongolia (9/952, 0.94%); in goats (1/51, 1.96%) from Tibet; and mosquitoes (6/131, 4.58%) from Yunnan. A total of 13 JEV envelope (E) gene sequences were amplified in pigs from Heilongjiang (5/13), Jilin (2/13) and Guangxi (6/13). Swine had the highest JEV infection rate of any animal species, and the highest infection rates were found in Heilongjiang. Phylogenetic analysis indicated that the predominant strain in Northern China was genotype I. Mutations were found at residues 76, 95, 123, 138, 244, 474 and 475 of E protein but all sequences had predicted glycosylation sites at 'N154. Three strains lacked the threonine 76 phosphorylation site from non-specific (unsp) and protein kinase G (PKG) site predictions; one lacked the threonine 186 phosphorylation site from protein kinase II (CKII) prediction; and one lacked the tyrosine 90 phosphorylation site from epidermal growth factor receptor (EGFR) prediction. The aim of the current study was to contribute to JEV prevention and control through the characterization of its molecular epidemiology and prediction of functional changes due to E-protein mutations.

Deterministic Processes Shape Abundant and Rare Bacterial Communities in Drinking Water.

The deep mechanisms shaping bacterial assembly are a crucial challenge in drinking water ecosystem. However, much less is known about seasonal diversity distributions and assembly mechanisms of abundant and rare bacteria in drinking water. The combination of environmental variables and high-throughput 16S rRNA gene sequencing was conducted to examine the composition, assembly, co-occurrence patterns of abundant and rare bacteria from five drinking water sites across four seasons in one year in China. The results indicated that abundant taxa were mainly composed of Rhizobiales_UG1, Sphingomonadales_UG1, and Comamonadaceae, while rare taxa were Sphingomonadales_UG1, Rhizobiales_UG2, and Rhizobiales_UG1. The richness of rare bacteria was greater than that of abundant ones, and the richness had no differences among seasons. The beta diversity was significantly discrepant in abundant and rare communities and among seasons. Deterministic mechanism accounted for a larger contribution to abundant taxa than rare taxa. Furthermore, water temperature had higher effects on abundant microbiome than rare ones. Co-occurrence network analysis indicated that abundant taxa that occupied frequently in central positions had stronger effect on co-occurrence network. In our study, these results collectively suggested that rare bacteria respond to environmental variables with an analogical pattern to abundant counterparts (similar community assembly), but their ecological diversities, driving forces, and co-occurrence patterns were not equivalent in drinking water.

Multi-omics methods reveal that putrescine and cadaverine cause different degrees of enrichment of high-risk resistomes and opportunistic pathogens in the water and sediment of the Yellow River.

Contamination of antibiotic resistomes due to animal carcass decay has become a serious environmental concern. However, the relationship between main metabolite compounds of corpse decomposition (i.e., putrescine and cadaverine) and antibiotic resistomes remains unclear. To tackle this issue, the response of antibiotic resistance genes (ARGs) and microbiome in aquatic environment to excess putrescine, cadaverine and a mixture of both based on laboratory simulation experiment was investigated by high-throughput quantitative PCR and amplicon sequencing methods. Our results showed putrescine and cadaverine led to the increasing of TC (total carbon) and TN (total nitrogen) both in water and sediment. Under the exposure of putrescine and cadaverine, the total abundance of mobile genetic elements (MGEs) and most ARGs in water was higher than in sediment. In particular, putrescine and cadaverine caused significantly different decreases in alpha diversity of microbial community in water and sediment compared with the control group. Microbial community structures both in water and sediment were also significantly affected by cadaverine and putrescine. Furthermore, putrescine and cadaverine led to different degrees of increases of high-risk ARGs (like mecA) and opportunistic pathogens (like Delftia) in sediment, promoting the prevalence of antibiotic resistant bacteria. In conclusion, our findings revealed the influences of main metabolites of carcass decay on microbiome and resistomes, providing references for risk assessment and pollution management.

Exosome-mediated macrophage regulation for inflammatory bowel disease repair: a potential target of gut inflammation.

Inflammatory bowel disease (IBD), which includes Crohn's disease (CD) and ulcerative colitis (UC), is a complex condition without a definite cause. During IBD, immune cells such as macrophages release proinflammatory cytokines and chemokines, contributing to intestinal barrier integrity dysfunction. IBD is largely influenced by macrophages, which are classified into subtypes M1 and M2. M1 macrophages have been found to contribute to the development of IBD, whereas M2 macrophages alleviate IBD. Hence, agents that cause increased polarization of the M2 phenotype could help repair IBD. Exosomes, as ubiquitous conveyors of intercellular messages, are involved in immune responses and immune-mediated disease processes. Exosomes and their microRNA (miRNA) from healthy cells have been found to polarize macrophages to M2 to repair IBD due to their anti-inflammatory properties; however, those from inflammatory-driven cells and disease cells promote M1 macrophages to perpetuate IBD. Here, we review the biogenesis, biochemical composition, and sources of exosomes, as well as the roles of exosomes as extracellular vesicles in regulation of macrophages to repair IBD.

The source, fate and prospect of antibiotic resistance genes in soil: A review.

Antibiotic resistance genes (ARGs), environmental pollutants of emerging concern, have posed a potential threat to the public health. Soil is one of the huge reservoirs and propagation hotspot of ARGs. To alleviate the potential risk of ARGs, it is necessary to figure out the source and fate of ARGs in the soil. This paper mainly reviewed recent studies on the association of ARGs with the microbiome and the transmission mechanism of ARGs in soil. The compositions and abundance of ARGs can be changed by modulating microbiome, soil physicochemical properties, such as pH and moisture. The relationships of ARGs with antibiotics, heavy metals, polycyclic aromatic hydrocarbons and pesticides were discussed in this review. Among the various factors mentioned above, microbial community structure, mobile genetic elements, pH and heavy metals have a relatively more important impact on ARGs profiles. Moreover, human health could be impacted by soil ARGs through plants and animals. Understanding the dynamic changes of ARGs with influencing factors promotes us to develop strategies for mitigating the occurrence and dissemination of ARGs to reduce health risks.

Hesperidin Inhibits Lung Cancer In Vitro and In Vivo Through PinX1.

New drugs or active leads with high efficiency and low toxicity are needed in the treatment of lung cancer. Natural products are an important source of anti-tumor drugs. At present, there are many molecular-targeted anti-tumor drugs derived from natural products or their derivatives for tumor treatment or in clinical trials. Hesperidin is a flavanone isolated from the Rutaceae plant lime Citrus aurantium L. or Citrus sinensis Osbeck. It has been considered to inhibit cancer cell viability in vitro. However, the effect of hesperidin on lung cancer and its underlying mechanism remain unclear. In this study, we found that the pinX1 expression level is closely related to overall survival and plays an important role in regulating lung cancer cell proliferation, migration, invasion, and senescence. More importantly, hesperidin significantly increased pinX1 protein expression, and knockdown pinX1 by its specific siRNA blocked the protective effects of hesperidin. Moreover, we also assessed that hesperidin at 100 mg/kg is safe in vivo. These findings showed that hesperidin is a potential therapeutic candidate for preventing the progression of lung cancer.

Scaffolding Protein GspB/OutB Facilitates Assembly of the Dickeya dadantii Type 2 Secretion System by Anchoring the Outer Membrane Secretin Pore to the Inner Membrane and to the Peptidoglycan Cell Wall.

The phytopathogenic proteobacterium Dickeya dadantii secretes an array of plant cell wall-degrading enzymes and other virulence factors via the type 2 secretion system (T2SS). T2SSs are widespread among important plant, animal, and human bacterial pathogens. This multiprotein complex spans the double membrane cell envelope and secretes fully folded proteins through a large outer membrane pore formed by 15 subunits of the secretin GspD. Secretins are also found in the type 3 secretion system and the type 4 pili. Usually, specialized lipoproteins termed pilotins assist the targeting and assembly of secretins into the outer membrane. Here, we show that in D. dadantii, the pilotin acts in concert with the scaffolding protein GspB. Deletion of gspB profoundly impacts secretin assembly, pectinase secretion, and virulence. Structural studies reveal that GspB possesses a conserved periplasmic homology region domain that interacts directly with the N-terminal secretin domain. Site-specific photo-cross-linking unravels molecular details of the GspB-GspD complex in vivo. We show that GspB facilitates outer membrane targeting and assembly of the secretin pores and anchors them to the inner membrane while the C-terminal extension of GspB provides a scaffold for the secretin channel in the peptidoglycan cell wall. Phylogenetic analysis shows that in other bacteria, GspB homologs vary in length and domain composition and act in concert with either a cognate ATPase GspA or the pilotin GspS. IMPORTANCE Gram-negative bacteria have two cell membranes sandwiching a peptidoglycan net that together form a robust protective cell envelope. To translocate effector proteins across this multilayer envelope, bacteria have evolved several specialized secretion systems. In the type 2 secretion system and some other bacterial machineries, secretins form large multimeric pores that allow transport of effector proteins or filaments across the outer membrane. The secretins are essential for nutrient acquisition and pathogenicity and constitute a target for development of new antibacterials. Targeting of secretin subunits into the outer membrane is often facilitated by a special class of lipoproteins called pilotins. Here, we show that in D. dadantii and some other bacteria, the scaffolding protein GspB acts in concert with pilotin, facilitating the assembly of the secretin pore and its anchoring to both the inner membrane and the bacterial cell wall. GspB homologs of varied domain composition are present in many other T2SSs.

Transplantation of umbilical cord blood-derived mesenchymal stem cells as therapy for adriamycin induced-cardiomyopathy.

Umbilical cord blood-derived mesenchymal stem cells (UCBMSCs) have been reported to possess cardioprotective effects in diseases. However, its effects on cardiomyopathy remain unclear. This study aimed to the therapeutic effects of UCBMSC transplantation on adriamycin (ADR)-induced cardiomyopathy. UCBMSCs isolated from human UCB were identified by detecting surface markers (CD29, CD90, CD34, and CD45) using flow cytometry. The effect of UCBMSCs on left ventricular end-diastolic dimension (LVEDD), left ventricular systolic end-diastolic diameter (LVESD), left ventricular ejection fraction (LVEF), and left ventricular fraction shortening (LVFS) were determined by echocardiography. Histological changes were observed by HE and Masson staining. The serum levels of collagen-I (Col-I), brain natriuretic peptide (BNP), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), creatine kinase (CK), CK-MB, interleukin (IL)-6, IL-10, and tumor necrosis factor alpha (TNF-α) were measured by corresponding kits. The protein levels of IL-6, IL-10, and TNF-α were measured by Western blotting. The isolated UCBMSCs manifested the positive expression of CD29 and CD90, and the negative expression of CD34 and CD45. UCBMSC transplantation significantly reduced LVEDD and LVESD, and increased LVEF and LVFS in ADR-induced cardiomyopathy model rats. Cardiac injury and high collagen deposition in model rats were alleviated by UCBMSC treatment. Moreover, UCBMSCs decreased the serum levels of Col-I, BNP, AST, LDH, CK, CK-MB, IL-6, IL-10, and TNF-α in model rats. Overall, UCBMSCs exert the therapeutic effects on ADR-induced cardiomyopathy through recovering the myocadiac function and alleviating the inflammatory response.

The association of PD-L1 gene polymorphisms with non-small-cell lung cancer susceptibility and clinical outcomes in a Chinese population.

OBJECTIVE: To investigate the influence of PD-L1 polymorphisms on the susceptibility of non-small-cell lung cancer (NSCLC) and the prognosis of NSCLC patients who undergo platinum-based chemotherapy. MATERIALS AND METHODS: 9 single nucleotide polymorphisms (SNPs) in the PD-L1 gene, including rs822336 (G>C), rs822337 (T>A), rs10815225 (G>C), rs7866740 (C>G), rs866066 (C>T), rs822338 (C>T), rs2890657 (C>G), rs2890658 (C>A), and rs229136 (C>G) were selected for this study. Genotyping was performed in 281 advanced NSCLC patients and 251 healthy volunteers using the matrix assisted laser desorption ionization time-of-flight (MALDI-TOF) method. RESULTS: The G allele of PD-L1 rs7866740 was significantly related to the risk of NSCLC. Compared with the C allele, the G allele an increase the risk of NSCLC (OR=3.532, 95% CI: 1.232-10.129, P=0.001). In terms of the clinical outcomes, PD-L1 rs2890658 C>A was significantly associated with both a worse progression-free survival (adjusted HR=1.367, 95% CI=1.0-1.8, P=0.038) and a worse overall survival (adjusted HR=1.402, 95% CI=1.0-1.9, P=0.026) of NSCLC patients. PD-L1 rs822336 G>C was significantly related to a worse overall survival (adjusted HR=1.393, 95% CI=1.1-1.8, P=0.021). CONCLUSIONS: PD-L1 rs7866740 C>G may play a role in the pathogenesis of NSCLC. PD-L1 rs2890658 C>A and rs822336 G>C are related to the prognoses of patients receiving platinum-based chemotherapy.

A randomized phase 2 trial of apatinib vs observation as maintenance treatment following first-line induction chemotherapy in extensive- stage small cell lung cancer.

Background The 5-year survival rate for extensive-disease small-cell lung carcinoma (ED-SCLC) is only 1%. Recently, apatinib exerted promising effects on cancer patients after failure of first-line chemotherapy. Methods This study enrolled 24 ED-SCLC patients to study the efficacy and toxicity of apatinib in combination with chemotherapy and maintenance therapy. The primary endpoints were overall survival (OS) and progression-free survival (PFS). The secondary endpoints included toxicity and safety. Apatinib was given 250 mg/day during the chemotherapy interval, and as maintenance therapy after 4-6 cycles until the patient progressed, died, or was intolerant to drug toxicity. The study further evaluated the cytotoxicity, cell-cycle arrest and apoptotic induction of apatinib in A549 and H446 cells. Results There was no difference in short-term efficacy between combined and chemotherapy groups. Long-term efficacy showed that the median PFS was 7.8 months and 4.9 months in combination and chemotherapy groups, respectively [p = 0.002, HR(95%CI): 0.18(0.06-0.60)]. The median OS was 12.1 months and 8.2 months in combination and chemotherapy groups, respectively [p = 0.023, HR(95%CI): 0.38 (0.16-0.90)]. Multivariate Cox regression analysis showed that apatinib combined with chemotherapy was an independent prognostic factor for OS and PFS. The ECOG score was an independent prognostic factor affecting OS. In vitro analysis showed that apatinib inhibited cell proliferation and caused cell-cycle arrest and apoptosis. Conclusion Apatinib combination/maintenance therapy showed promising efficacy and safety to extend OS/PFS in ED-SCLC and will be a potent therapeutic option in future practice. Although the scale of this study is small, further research on large sample sizes is needed.

First identification of a novel parvovirus distantly related to human bufavirus from diarrheal dogs in China.

Bufaviruses are small, nonenveloped, single-stranded DNA viruses belonging to the subfamily Parvovirinae. Human bufaviruses were first identified in 2012 in fecal samples from children with diarrhea. A new parvovirus of canines that was first detected in various samples from dogs with enteric and respiratory symptoms in Italy between 2014 and 2018 is closely related to the newly described human bufavirus. To explore the prevalence and genetic diversity of CBuV in Chinese dogs, 540 canine parvovirus (CPV)-positive serum and diarrhea samples were collected in Guangxi Province between 2016 and 2018. Among the samples, 6.25% (5/80) of rectal swabs and 2.5% (5/200) of CPV PCR-positive samples were positive for CBuV. However, the virus was not detected in CPV PCR-negative samples or nasal swabs. Two CBuV isolates were identified from CPV-positive fecal and serum samples by complete sequence analysis, with 99.8%-99.9% NS1 and VP2 protein identity to each another. Sequence analysis indicated that the CBuV GXNN01-2018 isolate VP2 protein shares 99.6% identity with the Italian CBuV ITA/2015/297 isolate and 62.3%-65.5% identity with human bufavirus. Phylogenetic analysis showed that CBuV was significantly distinct from other known bufaviruses and was most closely related to CBuV ITA/2015/297. This is the first report of the existence of CBuV in China, and our findings will strengthen the understanding of the epidemiology of bufaviruses in different animals.

The regulatory role of APE1 in epithelial-to-mesenchymal transition and in determining EGFR-TKI responsiveness in non-small-cell lung cancer.

BACKGROUND: Epithelial-to-mesenchymal transition (EMT) plays a pivotal role in resistance to EGFR tyrosine kinase inhibitors (TKIs) in non-small-cell lung cancer (NSCLC). Our previous study revealed that in osteosarcoma, human apurinic/apyrimidinic endonuclease 1 (APE1) regulates transforming growth factor-ß (TGF-ß), an important player in EMT. We therefore hypothesized a link between APE1 and EGFR-TKI responsiveness in NSCLC. METHODS: The protein levels of APE1 were analyzed in tumors of NSCLC patients receiving EGFR-TKI treatment. The correlation between APE1 expression and progression-free survival (PFS), overall survival (OS), or response rate were analyzed. The impact of APE1 on the response to EGFR-TKIs was measured by exogenous manipulation of APE1 in EGFR-TKI-sensitive and EGFR-TKI-resistant cells. RESULTS: We indicate that low expression of APE1 in tumors is associated with a significantly longer PFS (20.8 months vs 8.4 months, P = 0.008) and a preferential OS (39.0 months vs 17.0 months, P = 0.001), with no difference in initial response rate to EGFR-TKIs. We observed that APE1 protein level was significantly increased in EGFR-TKI-resistant cells and was associated with downregulated E-cadherin and upregulated vimentin. The EMT phenotype, as well as the levels of TGF-ß, was suppressed in APE1 knockdown HCC827/IR and PC-9/ER cells, while the EMT phenotype was promoted in APE1-overexpressed HCC827 and PC-9 cells. Furthermore, a specific APE1 redox inhibitor (ie, E3330) effectively reversed the EMT phenotype and further sensitized the cells to EGFR-TKIs. CONCLUSION: This study revealed a significant role of APE1 in EGFR-TKI resistance via novel regulatory effects on the EMT phenotype in NSCLC.

miR-513a-5p regulates radiosensitivity of osteosarcoma by targeting human apurinic/apyrimidinic endonuclease.

Radiotherapy in osteosarcoma patients is problematic due to radioresistance; therefore, understanding the mechanism of radioresistance is integral to providing effective radiotherapeutic regimens for osteosarcoma. We now report the activity of an miRNA, miR-513a-5p, in stimulating radiosensitivity of osteosarcoma cells in vitro and in vivo. MiR-513a-5p expression is decreased in osteosarcoma tissue from patients and cultured osteosarcoma cell lines. However, exogenous re-expression of this miRNA in osteosarcoma cell lines, including HOS, U2OS and 9901, can induce sensitization to ionizing radiation. We also confirm that miR-513a-5p suppresses APE1 expression, and that both the redox and DNA repair activity of APE1 were decreased in miR-513a-5p expressing cell lines. By suppressing APE1, miR-513a-5p induces the DNA damage response which stimulates apoptosis after irradiation. Our report establishes miR-513a-5p as a radiosensitizing miRNA and identifies its activity in the suppression of APE1, which could directly lead to radiosensitization.

APE1 deficiency promotes cellular senescence and premature aging features.

Base excision repair (BER) handles many forms of endogenous DNA damage, and apurinic/apyrimidinic endonuclease 1 (APE1) is central to this process. Deletion of both alleles of APE1 (a.k.a. Apex1) in mice leads to embryonic lethality, and deficiency in cells can promote cell death. Unlike most other BER proteins, APE1 expression is inversely correlated with cellular senescence in primary human fibroblasts. Depletion of APE1 via shRNA induced senescence in normal human BJ fibroblasts, a phenotype that was not seen in counterpart cells expressing telomerase. APE1 knock-down in primary fibroblasts resulted in global DNA damage accumulation, and the induction of p16INK4a and p21WAF1 stress response pathways; the DNA damage response, as assessed by γ-H2AX, was particularly pronounced at telomeres. Conditional knock-out of Apex1 in mice at post-natal day 7/12 resulted in impaired growth, reduced organ size, and increased cellular senescence. The effect of Apex1 deletion at post-natal week 6 was less obvious, other than cellular senescence, until ∼8-months of age, when premature aging characteristics, such as hair loss and impaired wound healing, were seen. Low APE1 expression in patient cancer tissue also correlated with increased senescence. Our results point to a key role for APE1 in regulating cellular senescence and aging features, with telomere status apparently affecting the outcome.

Stair-Step Pattern of Soil Bacterial Diversity Mainly Driven by pH and Vegetation Types Along the Elevational Gradients of Gongga Mountain, China.

Ecological understandings of soil bacterial community succession and assembly mechanism along elevational gradients in mountains remain not well understood. Here, by employing the high-throughput sequencing technique, we systematically examined soil bacterial diversity patterns, the driving factors, and community assembly mechanisms along the elevational gradients of 1800-4100 m on Gongga Mountain in China. Soil bacterial diversity showed an extraordinary stair-step pattern along the elevational gradients. There was an abrupt decrease of bacterial diversity between 2600 and 2800 m, while no significant change at either lower (1800-2600 m) or higher (2800-4100 m) elevations, which coincided with the variation in soil pH. In addition, the community structure differed significantly between the lower and higher elevations, which could be primarily attributed to shifts in soil pH and vegetation types. Although there was no direct effect of MAP and MAT on bacterial community structure, our partial least squares path modeling analysis indicated that bacterial communities were indirectly influenced by climate via the effect on vegetation and the derived effect on soil properties. As for bacterial community assembly mechanisms, the null model analysis suggested that environmental filtering played an overwhelming role in the assembly of bacterial communities in this region. In addition, variation partition analysis indicated that, at lower elevations, environmental attributes explained much larger fraction of the ß-deviation than spatial attributes, while spatial attributes increased their contributions at higher elevations. Our results highlight the importance of environmental filtering, as well as elevation-related spatial attributes in structuring soil bacterial communities in mountain ecosystems.

Mammalian APE1 controls miRNA processing and its interactome is linked to cancer RNA metabolism.

Mammalian apurinic/apyrimidinic endonuclease 1 is a DNA repair enzyme involved in genome stability and expression of genes involved in oxidative stress responses, tumor progression and chemoresistance. However, the molecular mechanisms underlying the role of apurinic/apyrimidinic endonuclease 1 in these processes are still unclear. Recent findings point to a novel role of apurinic/apyrimidinic endonuclease 1 in RNA metabolism. Through the characterization of the interactomes of apurinic/apyrimidinic endonuclease 1 with RNA and other proteins, we demonstrate here a role for apurinic/apyrimidinic endonuclease 1 in pri-miRNA processing and stability via association with the DROSHA-processing complex during genotoxic stress. We also show that endonuclease activity of apurinic/apyrimidinic endonuclease 1 is required for the processing of miR-221/222 in regulating expression of the tumor suppressor PTEN. Analysis of a cohort of different cancers supports the relevance of our findings for tumor biology. We also show that apurinic/apyrimidinic endonuclease 1 participates in RNA-interactomes and protein-interactomes involved in cancer development, thus indicating an unsuspected post-transcriptional effect on cancer genes.APE1 plays an important role in the cellular response to oxidative stress, and mutations are linked to tumor progression and chemoresistance. Here, the authors characterize the interactions of APE1 with RNA and demonstrate a role in microRNA processing.

Microbial diversity in Chinese temperate steppe: unveiling the most influential environmental drivers.

Temperate steppe is extremely sensitive to the current global changes. However, what are the main environmental variables driving microbial diversity in temperate steppe are still unclear, something that impairs doing predictions about the expected effects of global changes on microbe-mediated ecological functions. This is why, in this study, the relationship between soil microbial diversity and environmental variables in Chinese temperate steppe is investigated. In this study, significant correlations between soil bacterial α-diversity and mean annual precipitation and the aridity index were observed at the whole region scale. No clear correlations between microbial α-diversities and other measured environmental variables were found at the whole temperate steppe region and sub-regions. On the other hand, ß-diversity was strongly related to spatial variables and climate variables for bacteria, while spatial variables and soil organic matters were more related with fungal ß-diversity. In addition, the mean annual temperature was highly correlated with microbial ß-diversity at different spatial scales, suggesting that it could be a good single predictor of soil microbial assemblage in temperate steppe. ß-Diversities are more explained by combined effect of local environmental variables based on variation partitioning analysis, reflecting the community assemblage is more likely driven by species sorting through environmental filtering.