Cell cycle arrest mediated by Cd-induced DNA damage in Arabidopsis root tips

Accumulating evidence demonstrates that the aberrant expression of cell cycle regulation and DNA repair genes can result in abnormal cell proliferation and genomic instability in eukaryotic cells under different stresses. Herein, Arabidopsis thaliana (Arabidopsis) seedlings were grown hydroponically on 0.5 × MS media containing cadmium (Cd) at 0–2.5 mg L−1 for 5 d of treatment. Real time quantitative reverse transcription-polymerase chain reaction (qRT-PCR) analysis revealed that expression of DNA damage repair and cell cycle regulation genes, including BRCA1, MRE11, WEE1, CDKA;1 and PCNA1, showed an inverted U-shaped dose-response. In contrast, notably reduced expression was observed for G1-to-S transition-related genes, Histone H4, E2Fa and PCNA2; DSB end processing, GR1; G2-to-M transition-related gene, CYCB1;1; and DNA mismatch repair, MSH2, MSH6 and MLH1 genes in root tips exposed to 0.125–2.5 mg/L Cd for 5 d. Flow cytometry (FCM) analysis revealed significant increases of cells with a 2C nuclear content and with a 4C and 8C nuclear content under Cd stresses of 0.125 and 1–2.5 mg L−1, respectively. Our results suggest that 0.125 mg L−1 Cd-induced DNA damage induced the marked G1/S arrest, leading to accelerated growth in root tips, while 1.0–2.5 mg L−1 Cd-induced DNA damage caused a notable G2/M arrest in root tips, leading to reduced growth in root tips. This may be a protective mechanism that prevents cells with damaged DNA from dividing under Cd stress

Characterization of the micro-environment of the testis that shapes the phenotype and function of testicular macrophages

Tissue-specific macrophages are important for the activation of innate immune responses and general organ homeostasis. Testicular macrophages (TM) reside in the testicular interstitial space and comprise the largest leukocyte population in the testis and are assumed to play a role in maintaining testicular immune privilege. Numerous studies have indicated that the interstitial fluid (IF) surrounding the TM has immunosuppressive properties, which may influence the TM phenotype. However, the identity of the immunosuppressive molecules present in the IF is poorly characterized. In this thesis it is shown that in the rat, IF shifts the M1 phenotype of granulocyte macrophage-colony stimulating factor induced bone marrow derived macrophages towards the M2 phenotype. M2 macrophages polarized by IF mimic the properties of TM such as increased expression of CD163, high secretion of IL-10 and low secretion of TNF-alpha. In addition, IF-polarized macrophages display immunoregulatory functions by inducing the expansion of immunosuppressive regulatory T cells. This thesis provides evidence that PGE2, PGI2, testosterone and corticosterone are important immunoregulatory molecules in the IF, playing a relevant role in determining the phenotype of TM. Except corticosterone, all of these factors are able to inhibit the NF-kB signaling pathway to suppress the production of pro-inflammatory cytokines and thus maintain an immunosuppressive microenvironment of the testis. Corticosterone was found to be the principal immunosuppressive molecule in the IF. Its receptor, the glucocorticoid receptor, was found to be present in TM immunohistochemically. In addition, TM locally produce small amounts of corticosterone, which suppress the expression of inflammatory genes and render TM refractory to inflammatory stimuli. Taken together, these results suggest that testicular corticosterone shapes the immunosuppressive function and phenotype of TM. This steroid hormone may therefore play also an important role in the establishment and maintenance of the immune privilege of the testis.Gewebsspezifische Makrophagen haben eine wichtige Funktion bei der Aktivierung angeborener Immunantworten und der Organhomeostase. Testikuläre Makrophagen (TM) befinden sich im Interstitium des Hodens und stellen die größte Leukozytenpopulation in der männlichen Gonade dar. Es wird angenommen, dass sie eine wichtige Funktion in der Aufrechterhaltung des Immunprivilegs des Hodens ausüben. Studien haben gezeigt, dass die interstitielle Flüssigkeit (IF), wleche die TM umgibt, immunsuppressive Eigenschaften aufweist, die den Phänotyp der TM beeinflussen könnten. Allerdings konnten immunsuppressive Moleküle in der IF bislang kaum charakterisiert werden. In der vorliegenden Arbeit wird für die Ratte als Modell gezeigt, dass die IF den durch Granulozyten- Makrophagen-Kolonie-stimulierenden Faktor (GM-CSF) induzierten M1 Phänotyp von Makrophagen, die aus dem Knochenmark isoliert wurden, in Richtung des M2 Phänotyps verschieben kann. IF-polarisierte M2-Makrophagen zeigen damit charakteristische Eigenschaften von TM, wie z. Bsp. erhöhte Expression von CD163, hohe Level von sezerniertem IL-10 bei geringer TNF-alpha Sekretion. Darüber hinaus zeigen IF-polarisierte Makrophagen immunoregulatorische Funktionen, indem sie die Expansion von immunsuppressiven regulatorischen T-Zellen induzieren. In dieser Studie werden erstmals auch Ergebnisse vorgestellt, die zeigen, dass PGE2, PGI2, Testosteron und Corticosteron wichtige immunregulatorische Moleküle in der IF darstellen und eine wesentliche Rolle bei der Bestimmung des TM-Phänotyps spielen. Mit Ausnahme von Corticosteron sind die genannten Faktoren in der Lage, den NF-kB-Signalweg zu hemmen, und damit die Produktion von entzündungshemmenden Zytokinen zu unterdrücken. Bei Corticosteron war der NFkB Signalweg bei der Immunsuppression nicht blockiert. Corticosteron konnte als wichtigster immunsuppressiver Faktor in der IF identifiziert werden. Dessen Rezeptor, der Glucocorticoidrezeptor, konnte in TM mittels Immunhistochemie gefunden werden. TM produzieren lokal moderate Mengen an Corticosteron, die die Expression inflammatorischer Gene unterdrücken und TM unempfindlich gegenüber entzündlichen Stimuli machen können. Zusammengenommen zeigen diese Ergebnisse, dass testikuläres Corticosteron maßgeblich für die immunsuppressive Funktion und den spezifischen Phänotyp der TM verantwortlich ist. Damit könnte das Steroidhormon auch eine wichtige Rolle bei der Etablierung und Aufrechterhaltung des Immunprivilegs im Hoden spielen

Cadmium-induced genomic instability in Arabidopsis: molecular toxicological biomarkers for early diagnosis of cadmium stress

Microsatellite instability (MSI) analysis, random-amplified polymorphic DNA (RAPD), and methylation-sensitive arbitrarily primed PCR (MSAP-PCR) are methods to evaluate the toxicity of environmental pollutants in stress-treated plants and human cancer cells. Here, we evaluate these techniques to screen for genetic and epigenetic alterations of Arabidopsis plantlets exposed to 0–5.0 mg L−1 cadmium (Cd) for 15 d. There was a substantial increase in RAPD polymorphism of 24.5, and in genomic methylation polymorphism of 30.5–34.5 at CpG and of 14.5–20 at CHG sites under Cd stress of 5.0 mg L−1 by RAPD and of 0.25–5.0 mg L−1 by MSAP-PCR, respectively. However, only a tiny increase of 1.5 loci by RAPD occurred under Cd stress of 4.0 mg L−1, and an additional high dose (8.0 mg L−1) resulted in one repeat by MSI analysis. MSAP-PCR detected the most significant epigenetic modifications in plantlets exposed to Cd stress, and the patterns of hypermethylation and polymorphisms were consistent with inverted U-shaped dose responses. The presence of genomic methylation polymorphism in Cd-treated seedlings, prior to the onset of RAPD polymorphism, MSI and obvious growth effects, suggests that these altered DNA methylation loci are the most sensitive biomarkers for early diagnosis and risk assessment of genotoxic effects of Cd pollution in ecotoxicology

Evaluation of electrode-sample contact impedance under different curing humidity conditions during measurement of AC impedance of cement-based materials

Abstract In this study, a simple method was proposed to calculate electrode-sample contact impedance in the cases of two-point and four-point measurements. The results indicated that when using the saturated calcium hydroxide solution (SCH) as conductive medium, the contact impedance in the four-point measurement is negligible for the impedance range of cement-based materials. The SCH can be used as a reference for correction of the contact impedance. A reasonable combination of curing humidity and different conductive media is recommended for the two-point measurement, which is suitable for testing the ACIS of cement-based materials. In a case of contact impedance not being precisely known, it is highly recommended that a four-point measurement with two different ratios of the length of the sample and the center spacing of the voltage electrodes (L/a) should be conducted to evaluate the effect of the contact impedance following the procedure proposed in this study

Improvement of Cerebral Ischemia-Reperfusion Injury via Regulation of Apoptosis by Exosomes Derived from BDNF-Overexpressing HEK293

Brain-derived neurotrophic factor (BDNF) provides neuroprotective effects towards therapeutic cerebral ischemia-reperfusion (I/R) injury. This view has been proposed by more and more evidence. However, due to the lack of permeability of the blood-brain barrier (BBB) as well as the brief half-life in serum, clinical application is not widespread. To study the participation of exosomes containing BDNF in I/R, we isolated exosomes from BDNF-overexpressing HEK293. The protective outcomes of exosomes in hypoxia/reoxygenation (H/R) experiments were determined by the use of SY-5Y cells. Exosome-BDNF therapy restrained H/R-induced apoptosis by inhibition of the reducing levels of oxidative stress and calcium ions in the cells while maintaining stable levels of mitochondrial membrane potential in brain cells damaged by I/R. We then constructed a cerebral I/R injury model using SD rats to find the function of BDNF in exosome-mediated neuroprotection. The in vivo experiments conducted established that exosomes from BDNF-overexpressing HEK293 cells improved cerebral I/R injury by concealing neuronal apoptosis. Findings gained demonstrated that BDNF is a part of preventing cerebral I/R injury due to exosome mediation by regulating the cellular internal environment and inhibiting apoptosis

Incidence of microscopically positive proximal margins in adenocarcinoma of the gastroesophageal junction.

AIM: To investigate the incidence and risk factors of microscopically positive proximal margins in Chinese patients with adenocarcinoma of the gastroesophageal junction. METHODS: The medical records of 483 patients, who underwent surgical treatment with curative intent for adenocarcinoma of the gastroesophageal junction in a single high-volume tertiary medical center, were reviewed. Demographic, radiographic, endoscopic, pathologic, and treatment-related variables were evaluated. All proximal margins were re-evaluated by two experienced pathologists, and a positive proximal margin was defined as the microscopic presence of invasive tumor cells seen at the esophageal transaction margin submitted en face on final paraffin sections. RESULTS: The incidence of positive proximal margins was 23.81% in this series. Siewert type, depth of tumor invasion, lymph node involvement, presence of vascular or lymphatic invasion, and presence of perineural invasion were significantly associated with positive proximal margins. On multivariate analysis, the presence of vascular or lymphatic invasion and advanced-stage disease were independent risk factors for positive proximal margins in patients with adenocarcinoma of the gastroesophageal junction. CONCLUSION: Residual cancer at proximal resection margins remains a major issue for the surgical treatment of adenocarcinoma of the gastroesophageal junction in China

Recommendation of Crowdsourcing Tasks Based on Word2vec Semantic Tags

Crowdsourcing is the perfect show of collective intelligence, and the key of finishing perfectly the crowdsourcing task is to allocate the appropriate task to the appropriate worker. Now the most of crowdsourcing platforms select tasks through tasks search, but it is short of individual recommendation of tasks. Tag-semantic task recommendation model based on deep learning is proposed in the paper. In this paper, the similarity of word vectors is computed, and the semantic tags similar matrix database is established based on the Word2vec deep learning. The task recommending model is established based on semantic tags to achieve the individual recommendation of crowdsourcing tasks. Through computing the similarity of tags, the relevance between task and worker is obtained, which improves the robustness of task recommendation. Through conducting comparison experiments on Tianpeng web dataset, the effectiveness and applicability of the proposed model are verified

Preparation of Recombinant Human Collagen III Protein Hydrogels with Sustained Release of Extracellular Vesicles for Skin Wound Healing

Existing treatment methods encounter difficulties in effectively promoting skin wound healing, making this a serious challenge for clinical treatment. Extracellular vesicles (EVs) secreted by stem cells have been proven to contribute to the regeneration and repair of wound tissue, but they cannot be targeted and sustained, which seriously limits their current therapeutic potential. The recombinant human collagen III protein (rhCol III) has the advantages of good water solubility, an absence of hidden viral dangers, a low rejection rate and a stable production process. In order to achieve a site-specific sustained release of EVs, we prepared a rhCol III hydrogel by cross-linking with transglutaminase (TGase) from Streptomyces mobaraensis, which has a uniform pore size and good biocompatibility. The release profile of the rhCol III-EVs hydrogel confirmed that the rhCol III hydrogel could slowly release EVs into the external environment. Herein, the rhCol III-EVs hydrogel effectively promoted macrophage changing from type M1 to type M2, the migration ability of L929 cells and the angiogenesis of human umbilical vein endothelial cells (HUVECs). Furthermore, the rhCol III-EVs hydrogel is shown to promote wound healing by inhibiting the inflammatory response and promoting cell proliferation and angiogenesis in a diabetic rat skin injury model. The reported results indicate that the rhCol III-EVs hydrogel could be used as a new biological material for EV delivery, and has a significant application value in skin wound healing

Involvement of Aquaporin 3 in Helicobacter pylori-related gastric diseases.

BACKGROUND: Gastric cancer is one of the most common and lethal malignant cancers worldwide, and numerous epidemiological studies have demonstrated that Helicobacter pylori (H. pylori) infection plays a key role in the development of gastric carcinomas. Our previous studies showed that aquaporin 3 (AQP3) is overexpressed in gastric carcinoma and promotes the migration and proliferation of human gastric carcinoma cells, suggesting that AQP3 may be a potentially important determinant of gastric carcinoma. However, the role of AQP3 in H. pylori carcinogenesis is unknown. METHODS: The AQP3 protein and H. pylori were detected in human gastric tissues by immunohistochemistry and modified Giemsa staining respectively. AQP3 knockdown was obtained by small interfering (si) RNA. Western blot assays and RT-PCR were used to evaluate the change of AQP3 in the human gastric cancer AGS and SGC7901 cell lines after co-culture with H. pylori. Sprague Dawley rats were orally inoculated with H. pylori to establish a rat model colonized by H. pylori. RESULTS: The present study found that AQP3 expression correlated with H. pylori infection status in gastric cancer tissues and corresponding normal mucosa, and H. pylori co-culture upregulated AQP3 expression in human gastric adenocarcinoma cells in vitro via the extracellular signal-regulated kinase signaling pathway. H. pylori infection also increased AQP3 expression in gastric mucosa colonized by H. pylori in a Sprague Dawley rat model. CONCLUSIONS: These findings provide further information to understand the mechanism of H. pylori carcinogenesis and a potential strategy for the treatment of H. pylori-associated gastric carcinoma