[The regulation of tight junction protein via PKCα/β for abnormal permeability of brain microvascular endothelial cells exposed to paraquat]

Objective: To explore if conventional protein kinase C (cPKC: PKCα and PKCβ) contributes to paraquat (PQ) -induced abnormal permeability of mouse brain microvascular endothelial cells (BMECs) via the regulation of tight junction (TJ) proteins. Methods: The immortalized mouse brain endothelial cell line (bEnd.3) was used to establish a monolayer blood-brain barrier (BBB) model. In order to evaluate the function of the in vitro BBB model, the transendothelial electrical resistance (TEER) and permeability were measured by a Millicell-ERS volt-ohmmeter and sodium fluorescent (Na-FLU) , respectively. MTT assay was used to determine the relative survival rate of cells. The dose-response relationship was determined by treating cells with 0, 50, 100, 200, and 300 μmol/L PQ for 24 hours. The time-response relationship was determined by treating cells with 200 μmol/L PQ for 6, 12, 24, 48, and 72 hours. After the treatment of cells with 0, 100, 200, and 300 μmol/L PQ for 24 hours, the protein and mRNA expression levels of ZO-1, Occludin, and Claudin-5 were measured by immunofluorescence (IF) and quantitative real-time RT-PCR (qRT-PCR) , respectively; the expression of PKCα, PKCβ, phosphorylated (p) -PKCα, and p-PKCβ was determined by Western blot. After the treatment of cells with 200? mol/L PQ for 24 hours following the pretreatment with a classical PKC inhibitor (Go 6983, 1 μmol/L) for 1 hour, the protein expression of ZO-1, Occludin, Claudin-5, p-PKCα, and p-PKCβ was measured by Western blot. Results: The TEER of the bEnd. 3 cells increased gradually with the cell culture time, and reached a peak value of 114.3±6.9 Ω·cm(2) on day 6. According to the permeability analysis by Na-FLU, cell permeability gradually decreased with the cell culture time, and reached 1.7±0.2 cm/min on day 6, suggesting a well-behaved barrier function of cells. Compared with the control group, the survival rates of the bEnd.3 cells were significantly reduced after exposure to 100, 200, or 300 μmol/L PQ for 24 hours (P<0.05) , or after exposure to 200 μmol/L PQ for 6, 12, 24, 48, or 72 hours (P <0.05) , indicating a dose-and time-dependent relationship. The IF and qRT-PCR results showed that the protein and mRNA expression levels of ZO-1, Occludin, and Claudin-5 were significantly reduced with the increase in the concentration of PQ (P<0.05) . The Western blot analysis showed that compared with the control group, cells exposed to PQ had significantly higher protein expression of p-PKCα and p-PKCβ and significantly lower protein expression of ZO-1, Occludin, and Claudin-5 (P<0.05) . Compared with the PQ treatment group, the Go 6983 intervention group had significantly higher protein expression of ZO-1, Occludin, and Claudin-5 and significantly lower protein expression of p-PKCα and p-PKCβ (P<0.05) . Conclusion: By activation of cPKC (PKCα and PKCβ) , PQ reduces the protein and mRNA expression of TJ proteins and enhances the permeability of murine BMECs.

[Role of MAPK signaling pathway in epithelial-mesenchymal transition of type II alveolar epithelial cells induced by Paraquat]

Objective: To investigate the roles of p38 mitogen-activated protein kinases (p38 MAPK) , extracellular regulated protein kinases (ERK) and c-Jun N-tenninal kinases (JNK) of MAPK signaling pathway in Paraquat-induced epithelial to mesenchymal transition (EMT) of type II alveolarepithelial cells. Methods: RLE-6NT cells were incubated with different concentrations of PQ (0, 25, 50, 100μmol/L) for 6, 12 and 24 h. Cell morphology alteration was observed under phase-contrast microscopy. Cell viability was determined using an MTT assay. Cell migration ability was detected using scratch wound assay. Protein expression of P-p38 MAP, P-Erk1/2, P-JNK, E-cad, ZO-1, Vimentin and а-SMA were detected by western blot. The level of genes related to fibrosis (COL-I, COL-III, FN and FSP-1) were analyzed via quantitative real-time RT-PCR. Results: Cell morphology started to undergo EMT changes with a phenotype characteristic of mesenchymal cells, including an elongated shape and a lack of tight cell-cell adhesions induced by 100μmol/L PQ treatment in a time-dependent manner. MTT showed that cell viability decreased with increasing PQ concentration (50、100、200、300 μmol/L PQ treatment for 24 h) and increasing treatment time (200 μmol/L PQ treatment for 6, 12, 24, 36, 48 h) . Compared to control group, the expressions of the epithelial phenotype marker E-cad and ZO-1 significantly decreased with PQ treatment (50, 100μmol/L) in a time-dependent manner (P<0.05) . Additionally, the level of the mesenchymal marker (a-SMA, vimentin) dramatically increased with PQ treatment in the same concentration-and time-dependent manner (P<0.05) . Cell migration ability was markedly increased after 24 h of 100 μmol/L PQ treatment compared to control (P<0.05) . The phosphorylated forms of p38 MAPK, Erk1/2, and JNK were increased at 24 h after stimulation with PQ (P<0.05) . This PQ induced (100 μmol/L) phosphorylation was markedly attenuated in the presence of the p38 MAPK, ERK and JNK inhibitors (SB-203580, SP-600125 and PD98059) respectively. Furthermore, RT-PCR showed that PQ significantly induced the upregulation expression of COL I and III mRNA, Fn, and FSP-1 mRNA (P<0.05) . Conclusion: PQ-induced pulmonary fibrosis occurs via EMT, which is mediated by the MAPK pathway.

[Study on the mechanism of brain damage based on structural covariant network to evaluate the brain structure of nicotine addicts]

Objective: To explore the neuromechanism of nicotine dependence, structural covariation networks (SCNs) based on voxel-based morphometry (VBM) were used to study the synergistic changes in gray matter volume in different cerebral cortices of nicotine dependent individuals. Methods: During the period from August 2016 to February 2018, a total of 118 long-term smokers and 57 non-smoking healthy controls (both 18-55 male volunteers) through online platforms and leaflets were recruited. The subjects were scanned with SIEMENS Skyro 3.0T magnetic resonance scanner and underwent routine MRI sequence (preliminary elimination of intracranial lesions) and 3D-T1 (3D-mprage) sequence structure. Two imaging experts used Matlab software platform to carry on segmentation by using SPM8, and to find out the differences between the two groups of brain regions, and differences in brain regions as region of interest (ROI) structure association network analysis. Results: The gray matter volume (GMV) of the right anterior central gyrus and the left inferior parietal lobe in the smoking group decreased(voxels size were 55 and 284, respectively), and no gray matter volume (GMV) area increased. The network structure of covariant analysis found that when the inferior parietal lobe as the seed points, the smoking group showed a rising trend in left parietal lobe and left temporal pole, bilateral middle temporal gyrus, left postcentral gyrus and right middle frontal gyrus gray matter volume, and a downtrend in the right side of the left medial frontal gyrus, superior parietal lobe, bilateral temporal gyrus, left cingulate gyrus and left cerebellum (central) compared with the control group. Conclusion: In long-term smokers, there is a volume change of gray matter in the brain structure. Abnormal changes in the structure covariant network of the inferior parietal lobe can lead to impaired brain function in nicotine dependent patients.

[Structural changes of brain gray matter in male long-term smokers under magnetic resonance imaging]

Objective: To evaluate gray matter structure changes in long-term male smokers by voxel-based morphological method. Methods: Fifty long-term smokers and 37 non-smoking healthy volunteers were scanned with Siemens Skyro 3.0T magnetic resonance scanner from August 2014 to August 2016. The subjects underwent routine MRI (excluding intracranial lesions) sequences and 3D-T1 structural sequences (3D-mprage). SPM8 pretreatment based on Matlab was used to analyze the structural data. All of the data were analyzed by SPM8 software. The data were compared between groups with independent sample t test. Spearman correlation analysis was used to analyze the relationship between gray matter volume (GMV) and smoking data of two groups. Results: The gray matter volume of bilateral thalamic, right supramarginal gyrus, left supramarginal gyrus and left putamen of smoking group were (0.55±0.07), (0.40±0.05), (0.48±0.07) and (0.14±0.04) voxels, respectively, and the gray matter volume of the corresponding gyri in control group were (0.61±0.09), (0.43±0.06), (0.54±0.07) and (0.16±0.03) voxels, respectively; and the gray matter volume of smoking group were all lower than those in control group (t=-3.81, -3.51, -3.86, -2.33, all P<0.05), family wise error (FWE) correction (P<0.05). The gray matter volume of bilateral thalamus, right supramarginal gyrus and left putamen was negatively correlated with smoking index (r=-0.368, -0.189, -0.274, all P<0.05), and also negatively correlated with smoking years (r=-0.391, -0.221, -0.355, all P<0.05), and bilateral thalamus gray matter volume was negatively correlated with daily cigarette smoking (r=-0.186, P<0.05). Conclusion: The changes of brain structure of smokers mainly occur on reward-related pathways and marginal systems, and related to accumulation of cigarette smoking.

Integrative Profiling of Bee Communities from Habitats of Tropical Southern Yunnan (China)

Understanding and managing pollination service is hindered by taxonomic impediments and paucity of data, particularly in the tropics. Herein we apply integrative species delineation and taxonomy to test impacts of land use on the diversity of bee communities within Xishuangbanna (Yunnan, south China), a highly biodiverse tropical region which has undergone extensive land conversion to rubber plantation. 128 Operational Taxonomic Units (OTU) were inferred by an iterative and integrative approach. Bee activity differed significantly across land use samples, although community composition corresponded more to level of vegetation density, when accounting for spatial structure. Species diversity was high in young rubber plantations, although composition overlapped with other species-rich habitats (natural forest edge and river banks), and older plantations (>8 years) showed very low diversity under all measures. Community structures were similar between the natural forest interior and edge, although analysis indicated contrasting drivers of diversity, with clustering in the interior and overdispersion in the forest edge. Further, phylogenetic diversity and derived indices were underestimated when reference data were omitted from analysis. The description of bee communities herein permits more informed choices in land management with respect to ensuring continuation of essential services by bees.

miRNA-directed regulation of VEGF in tilapia under hypoxia condition

The Nile tilapia represents an excellent model for hypoxia tolerance. Vascular endothelial growth factor (VEGF) plays a key role in physiological blood vessel formation and pathological angiogenesis under hypoxia conditions. Tight regulation of VEGF level is necessary for hypoxia adaptation in tilapia. MicroRNAs (miRNAs) function as important regulators of gene expression at the post-transcriptional level, which are usually involved in stress responses. We reasoned that VEGF level could be regulated by miRNAs. Through bioinformatics analysis, we identified a putative miR-204 binding site in the VEGF mRNA. We found that hypoxia leads to a marked up-regulation in VEGF level, but a decrease in miR-204 level. miR-204 directly regulates VEGF expression by targeting its 3'-UTR, and inhibition of miR-204 substantially increases VEGF level in vivo. Moreover, we found that miR-204 loss of function could affect blood O2-carrying capacity, anaerobic metabolism, and antioxidant enzyme activity. Taken together, miR-204 is an endogenous regulator of VEGF expression, which participates in a regulatory circuit that allows rapid gene program transitions upon hypoxia stress.

MicroRNA repertoire for functional genome research in tilapia identified by deep sequencing

The Nile tilapia (Oreochromis niloticus; Cichlidae) is an economically important species in aquaculture and occupies a prominent position in the aquaculture industry. MicroRNAs (miRNAs) are a class of noncoding RNAs that post-transcriptionally regulate gene expression involved in diverse biological and metabolic processes. To increase the repertoire of miRNAs characterized in tilapia, we used the Illumina/Solexa sequencing technology to sequence a small RNA library using pooled RNA sample isolated from the different developmental stages of tilapia. Bioinformatic analyses suggest that 197 conserved and 27 novel miRNAs are expressed in tilapia. Sequence alignments indicate that all tested miRNAs and miRNAs* are highly conserved across many species. In addition, we characterized the tissue expression patterns of five miRNAs using real-time quantitative PCR. We found that miR-1/206, miR-7/9, and miR-122 is abundantly expressed in muscle, brain, and liver, respectively, implying a potential role in the regulation of tissue differentiation or the maintenance of tissue identity. Overall, our results expand the number of tilapia miRNAs, and the discovery of miRNAs in tilapia genome contributes to a better understanding the role of miRNAs in regulating diverse biological processes.

Strategies for hypoxia adaptation in fish species: a review

Aquatic environments exhibit wide temporal and spatial variations in oxygen levels compared to terrestrial environments. Fish are an excellent model for elucidating the underlying mechanisms of hypoxia adaptation. Over the past decade, several hypoxia-related proteins have been reported to act in concert to convey oxygen change information to downstream signaling effectors. Some signaling pathways, such as redox status, AMPK, MAPK and IGF/PI3K/Akt, are known to play a central role in hypoxia adaptation. These networks regulate oxygen-sensitive transcription factors which, in turn, affect the expression of hypoxia adaptation-related genes. This review summarizes current insights into hypoxia adaptation-related proteins and signaling pathways in fish.

microRNA regulation of skin pigmentation in fish

MicroRNAs (miRNAs) are endogenous small non-coding RNAs that play crucial roles in numerous biological processes. However, the role of miRNAs in skin color determination in fish has not been completely determined. Here, we identified that 13 miRNAs are differentially expressed between red and white skin. The analysis of miRNA spatial and temporal expression patterns suggests that miR-429 is potential regulator of skin pigmentation. miR-429 silencing results in a obvious change in skin pigmentation. Bioinformatics analysis and luciferase reporter assay shows that miR-429 directly regulates Foxd3 expression by targeting its 3′ untranslated (3′-UTR) region. miR-429 silencing leads to a significant increase in Foxd3 expression in vivo, thereby repressing the transcription of MITF and its downstream genes such as TYR, TYRP1, or TYRP2. These findings would provide a novel insight into the determination of skin color in fish.

miR-206 regulates the growth of the teleost tilapia (Oreochromis niloticus) through the modulation of IGF-1 gene expression

MicroRNAs (miRNAs) are ~22-nucleotide noncoding RNAs that play a crucial role in regulating muscle development. Our previous study shows that miR-206 is specifically expressed in tilapia skeletal muscle, and exhibits a dynamic expression pattern at different developmental stages. Here, we reveal that miR-206 emerges as a crucial regulator of tilapia growth. miR-206 loss of function leads to the acceleration of tilapia growth. IGF-1 is identified as the target gene of miR-206. miR-206 directly changes IGF-1 expression by targeting its 3' UTR, and inhibition of miR-206 substantially increases the IGF-1 mRNA level in vivo. Thus, miR-206 could be developed as a molecular marker to assist fish breeding.

Genetic analysis of four porcine avian influenza viruses isolated from Shandong, China

A Bayesian phylogenetic analysis of eight separate gene segments indicated A/Swine/Shandong/2/2003 (H5N1), A/Swine/Shandong/na/2003 (H9N2), A/Swine/Shandong/nb/2003 (H9N2) and A/Swine/Shandong/nc/2005 (H9N2) probably represent two multiple reassortant lineages, that had not been described before, with genes coming from H5N1, H9N2 and other lineages from poultry in Asia. Amino acid motifs within the haemagglutinin sequence of A/Swine/Shandong/nb/2003 suggested it may be able to infect people, whereas the sequences of the other three isolates suggested they would not have had that capability. Our analysis emphasizes the need for a comprehensive study of the interactions between H5N1 and H9N2 viruses in Asia that includes sequencing and phylogenetic investigation.