Blood-brain barrier (BBB) leakage plays a key role in cerebral ischemia-reperfusion injury. It is quite necessary to further explore the characteristic and mechanism of BBB leakage during stroke. We induced a focal cerebral ischemia model by transient middle cerebral artery occlusion in male rats for defining the time course of BBB permeability within 120 h following reperfusion and evaluate the specific role of tight junction (TJ) associated proteins claudin-5, occludin, and ZO-1 as well as protein kinase C delta (PKCδ) pathway in BBB leakage induced by reperfusion injury. We verified a bimodal increase in the permeability of the BBB following focal ischemia by Evans blue assay. Two peaks of BBB permeability appeared at 3 h and 72 h of reperfusion after 2 h focal ischemia, respectively. The leak at the endothelial cell was represented at the level of transmission electron microscopy. TTC staining results showed increased infarct size with time after cerebral ischemia reperfusion. The mRNA and protein expression levels of these three TJ associated proteins were significantly decreased compared with the sham-operated group within 120 h of reperfusion, corresponding to the time-dependent change of the biphasic pattern in BBB leakage. The redistribution of claudin-5, occludin, and ZO-1 in ischemia brain microvascular endothelial cells was observed at the same time points. In addition, Western blot assay revealed PKCδ level was also significantly increased in a similar biphasic pattern to above results within 120 h after cerebral ischemia-reperfusion. This study demonstrates the timing of TJ associated proteins claudin-5, occludin, and ZO-1 in light of BBB permeability associated with cerebral ischemia reperfusion, and suggests PKCδ pathway may participate in TJ barrier open and BBB leakage during reperfusion injury in a time-dependent manner.
The PREDICTS project—Projecting Responses of Ecological Diversity In Changing Terrestrial Systems (www.predicts.org.uk)—has collated from published studies a large, reasonably representative database of comparable samples of biodiversity from multiple sites that differ in the nature or intensity of human impacts relating to land use. We have used this evidence base to develop global and regional statistical models of how local biodiversity responds to these measures. We describe and make freely available this 2016 release of the database, containing more than 3.2 million records sampled at over 26,000 locations and representing over 47,000 species. We outline how the database can help in answering a range of questions in ecology and conservation biology. To our knowledge, this is the largest and most geographically and taxonomically representative database of spatial comparisons of biodiversity that has been collated to date; it will be useful to researchers and international efforts wishing to model and understand the global status of biodiversity.
Human use of the land (for agriculture and settlements) has a substantial negative effect on biodiversity globally. However, not all species are adversely affected by land use, and indeed, some benefit from the creation of novel habitat. Geographically rare species may be more negatively affected by land use than widespread species, but data limitations have so far prevented global multi-clade assessments of land-use effects on narrow-ranged and widespread species. We analyse a large, global database to show consistent differences in assemblage composition. Compared with natural habitat, assemblages in disturbed habitats have more widespread species on average, especially in urban areas and the tropics. All else being equal, this result means that human land use is homogenizing assemblage composition across space. Disturbed habitats show both reduced abundances of narrow-ranged species and increased abundances of widespread species. Our results are very important for biodiversity conservation because narrow-ranged species are typically at higher risk of extinction than widespread species. Furthermore, the shift to more widespread species may also affect ecosystem functioning by reducing both the contribution of rare species and the diversity of species’ responses to environmental changes among local assemblages.
Aberrant expression of noncoding RNAs in glioma cells, including long noncoding RNAs (lncRNAs) and microRNAs, may participate in the progression of glioma. Encoded by Growth Arrest-Specific 5 (GAS5) gene, lncRNA Gas5 was reported to be a negative regulator for survival and proliferation of several cancers. Here, Gas5 is found to be downregulated in glioma specimens and U87 and U251 glioma cell lines. We showed that the introduction of Gas5 by plasmid transfection increased the expression of tumor suppressor Bcl-2-modifying factor (bmf) and Plexin C1 via directly targeting and reducing the expression of miR-222. Downregulated expression of miR-222 inhibited U87 and U251 cell proliferation and promoted the apoptosis by upregulating bmf. As downstream signaling molecules of bmf, Bcl-2 and Bax were involved in the process. Meanwhile, knockdown of miR-222 attenuated U87 and U251 cell migration and invasion by upregulating Plexin C1, and cofilin was a crucial regulator targeted by Plexin C1. Gas5 combined with the knockdown of miR-222 resulted in the smallest tumor volumes and the longest survivals of nude mice in vivo. In summary, we show that Gas5 suppresses tumor malignancy by downregulating miR-222, which may serve as a promising therapy for glioma.
Colorectal neoplasia differentially expressed (CRNDE) is the most upregulated long noncoding RNA (lncRNA) in glioma. Herein, the function and potential molecular mechanisms of CRNDE and miR-384 were illustrated in glioma cells. CRNDE overexpression facilitated cell proliferation, migration, and invasion, while inhibited glioma cells apoptosis. Quantitative real-time polymerase chain reaction (PCR) demonstrated that miR-384 was downregulated in human glioma tissues and glioma cell lines. Moreover, restoration of miR-384 exerted tumor-suppressive functions. In addition, the expression of miR-384 was negatively correlated with CRNDE expression. A binding region between CRNDE and miR-384 was confirmed using luciferase assays. Moreover, CRNDE promoted cell malignant behavior by decreasing miR-384 expression. At the molecular level, treatment by CRNDE knockdown or miR-384 overexpression resulted in a decrease of piwi-like RNA-mediated gene silencing 4 (PIWIL4) protein. Besides, PIWIL4 was identified as a target of miR-384 and plays an oncogenic role in glioma. Similarly, downstream proteins of PIWIL4 such as STAT3, cyclin D1, VEGFA, SLUG, MMP-9, caspase 3, Bcl-2, and bcl-xL were modulated when treated with miR-384 and PIWIL4. Remarkably, CRNDE knockdown combined with miR-384 overexpression led to tumor regression in vivo. Overall, these results depicted a novel pathway mediated by CRNDE in glioma, which may be a potential application for glioma therapy.
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