Activation of Wnt/ß-catenin signaling by Zeb1 in endothelial progenitors induces vascular quiescence entry.

The establishment of a functional vasculature requires endothelial cells to enter quiescence during the completion of development, otherwise pathological overgrowth occurs. How such a transition is regulated remains unclear. Here, we uncover a role of Zeb1 in defining vascular quiescence entry. During quiescence acquisition, Zeb1 increases along with the progressive decline of endothelial progenitors' activities, with Zeb1 loss resulting in endothelial overgrowth and vascular deformities. RNA sequencing (RNA-seq) and assay for transposase-accessible chromatin sequencing (ATAC-seq) analyses reveal that Zeb1 represses Wif1, thereby activating Wnt/ß-catenin signaling. Knockdown of Wif1 rescues the overgrowth induced by Zeb1 deletion. Importantly, local administration of surrogate Wnt molecules in the retina ameliorates the overgrowth defects of Zeb1 mutants. These findings show a mechanism by which Zeb1 induces quiescence of endothelial progenitors during the establishing of vascular homeostasis, providing molecular insight into the inherited neovascular pathologies associated with human ZEB1 mutations, suggesting pharmacological activation of Wnt/ß-catenin signaling as a potential therapeutical approach.

Hydrogen Generation by Hydrolysis of MgH2-LiH Composite.

As a most promising material for hydrogen generation by hydrolysis, magnesium hydride (MgH2) is also trapped by its yielded byproduct Mg(OH)2 whose dense passivated layers prevent the further contact of intimal MgH2 with water. In this work, LiH, as a destroyer, has been added to promote the hydrogen properties of MgH2. The results demonstrate that even 3 wt % LiH was added into MgH2-G, the hydrogen generation yield can increase about 72% compared to the hydrogen generation yield of MgH2-G. The possible mechanism is that Mg2+ from the hydrolysis of MgH2 preferentially bound with OH- ions from the hydrolysis of LiH to form Mg(OH)2 precipitation, which is dispersed in water rather than coated on the surface of MgH2. Moreover, adding MgCl2 into hydrolysis solution, using ball milling technology, and increasing the hydrolysis temperature can make the hydrolysis rate higher and reaction process more complete. It is noted that a too high weight ratio of LiH with too high of a hydrolysis temperature will make the reaction too violent to be safe in the experiment. We determinate the best experimental condition is that the LiH ratio added into MgH2 is 3 wt %, the hydrolysis temperature is 60 °C, and the concentration of MgCl2 hydrating solution is 1 M. MgH2-LiH composite hydrogen generation technology can meet the needs of various types of hydrogen supply and has broad application prospects.

FGF13 Is Required for Histamine-Induced Itch Sensation by Interaction with NaV1.7.

Itch can be induced by activation of small-diameter DRG neurons, which express abundant intracellular fibroblast growth factor 13 (FGF13). Although FGF13 is revealed to be essential for heat nociception, its role in mediating itch remains to be investigated. Here, we reported that loss of FGF13 in mouse DRG neurons impaired the histamine-induced scratching behavior. Calcium imaging showed that the percentage of histamine-responsive DRG neurons was largely decreased in FGF13-deficient mice; and consistently, electrophysiological recording exhibited that histamine failed to evoke action potential firing in most DRG neurons from these mice. Given that the reduced histamine-evoked neuronal response was caused by knockdown of FGF13 but not by FGF13A deficiency, FGF13B was supposed to mediate this process. Furthermore, overexpression of histamine Type 1 receptor H1R, but not H2R, H3R, nor H4R, increased the percentage of histamine-responsive DRG neurons, and the scratching behavior in FGF13-deficient mice was highly reduced by selective activation of H1R, suggesting that H1R is mainly required for FGF13-mediated neuronal response and scratching behavior induced by histamine. However, overexpression of H1R failed to rescue the histamine-evoked neuronal response in FGF13-deficient mice. Histamine enhanced the FGF13 interaction with NaV1.7. Disruption of this interaction by a membrane-permeable competitive peptide, GST-Flag-NaV1.7CT-TAT, reduced the percentage of histamine-responsive DRG neurons, and impaired the histamine-induced scratching, indicating that the FGF13/NaV1.7 interaction is a key molecular determinant in the histamine-induced itch sensation. Therefore, our study reveals a novel role of FGF13 in mediating itch sensation via the interaction of NaV1.7 in the peripheral nervous system.SIGNIFICANCE STATEMENT Scratching induced by itch brings serious tissue damage in chronic itchy diseases, and targeting itch-sensing molecules is crucial for its therapeutic intervention. Here, we reveal that FGF13 is required for the neuronal excitation and scratching behavior induced by histamine. We further provide the evidence that the histamine-evoked neuronal response is mainly mediated by histamine Type 1 receptor H1R, and is largely attenuated in FGF13-deficent mice. Importantly, we identify that histamine enhances the FGF13/NaV1.7 interaction, and disruption of this interaction reduces histamine-evoked neuronal excitation and highly impairs histamine-induced scratching behavior. Additionally, we also find that FGF13 is involved in 5-hydroxytryptamine-induced scratching behavior and hapten 1-fluoro-2,4-dinitrobenzene-induced chronic itch.

α-Tubulin Acetylation Restricts Axon Overbranching by Dampening Microtubule Plus-End Dynamics in Neurons.

Axon growth is tightly controlled to establish functional neural circuits during brain development. Despite the belief that cytoskeletal dynamics is critical for cell morphology, how microtubule acetylation regulates axon development in the mammalian central nervous system remains unclear. Here, we report that loss of α-tubulin acetylation by ablation of MEC-17 in mice predisposes neurons to axon overbranching and overgrowth. Introduction of MEC-17F183A lacking α-tubulin acetyltransferase activity into MEC-17-deficient neurons failed to rescue axon defects. Moreover, loss of α-tubulin acetylation led to increases in microtubule debundling, microtubule invasion into filopodia and growth cones, and microtubule plus-end dynamics along the axon. Taxol application dampened microtubule hyperdynamics and suppressed axon overbranching and overgrowth in MEC-17-deficient neurons. Thus, our study reveals that α-tubulin acetylation acts as a brake for axon overbranching and overgrowth by dampening microtubule dynamics, providing insight into the role of microtubule post-translational modifications in regulating neural development.

ESE1 is Associated with Neuronal Apoptosis in Lipopolysaccharide Induced Neuroinflammation.

Neuronal apoptosis induced by the over-activation of microglia during neuroinflammation contributes to the pathology of central nervous system (CNS) degenerative diseases. ESE1 regulates apoptosis of intestinal epithelial cells in ulcerative colitis via accelerating NF-κB activation. NF-κB activation participates in neuronal apoptosis. However, the expression and functions of ESE1 in neuronal apoptosis during CNS inflammatory response remain unclear. In present study, ESE1 expression significantly increased in cerebral cortex after lipopolysaccharide (LPS) intracerebroventricular injection. Immunofluorescence staining indicated that ESE1 was located in neurons. Furthermore, there was a concomitant up-regulation of apoptotic markers including active caspase-3, BAX and decreased expression of anti-apoptosis protein Bcl-2. In vitro, ESE1 depletion in cortical primary neurons inhibited active caspase-3 and BAX expression as well as lactate dehydrogenase (LDH) release with up-regulation of Bcl-2, while ESE1 overexpression can exert opposite effects, indicating that ESE1 promoted neuronal apoptosis induced by LPS or LPS exposed microglia conditioned media (CM). ESE1 accelerated NF-κB activation in neurons with CM treatment. Collectively, all these data suggested that ESE1 might boost neuronal apoptosis during neuroinflammation via up-regulating NF-κB activation. These findings have implications on the potential target of ESE1 in CNS inflammation treatment.

Upregulation of PRDM5 Is Associated with Astrocyte Proliferation and Neuronal Apoptosis Caused by Lipopolysaccharide.

PRDM5 (PR domain containing 5) belongs to PRDM family which consists of transcriptional regulators that modulate cellular processes such as cell growth, differentiation and apoptosis. However, the function of PRDM5 in central nervous system (CNS) inflammatory response is unknown. In recent study, an adult rat neuroinflammation model via lipopolysaccharide (LPS) lateral ventricle injection was constructed. PRDM5 expression was increased in activated astrocytes and apoptotic neurons of the adult rat cerebral cortex after LPS injection. In vitro studies showed that the remarkable upregulation of PRDM5 might be involved in rat primary astrocyte proliferation and rat primary neuronal apoptosis in the cerebral cortex following LPS administration. In addition, using PRDM5 RNA interference both in rat primary asrtocytes and neurons, further indicated that PRDM5 was required for astrocyte proliferation and neuronal apoptosis induced by LPS. Our findings on the cellular signaling pathway may provide a new therapeutic strategy against neuroinflammation in the CNS.

SMAD4 is Involved in the Development of Endotoxin Tolerance in Microglia.

Initial exposure of macrophages to LPS induces hyporesponsiveness to a second challenge with LPS, a phenomenon termed LPS tolerance. Smad4 plays important roles in the induction of LPS tolerance. However, the function of Smad4 in microglia remains unknown. Here we show that expression of Smad4 was highly up-regulated in LPS-tolerized mouse cerebral cortex. Smad4 was mostly colocalized with microglia, rarely with neurons. Using a microglia cell line, BV2, we find that LPS activates endogenous Smad4, inducing its migration into the nucleus and increasing its expression. Smad4 significantly suppressed TLR-triggered production of proinflammatory cytokines (IL-6), increased anti-inflammatory cytokine in LPS-tolerized microglia. Moreover, IL-6 concentrations in culture supernatants after second LPS challenge are higher in SMAD4 small interfering RNA (siRNA) BV2 cells than control siRNA BV2 cells, indicating failure to induce tolerance in absence of Smad4 signaling. In our study, we conclude that both in vivo and in vitro, Smad4 signaling is required for maximal induction of endotoxin tolerance.

CDK14 Contributes to Reactive Gliosis via Interaction with Cyclin Y in Rat Model of Spinal Cord Injury.

Cyclin-dependent kinases (CDKs) are perceived as the engine that drives cell cycle progression whereas cyclins are considered to be the gears that are changed to aid the transition between cycle phases. CDK14 is a cdc2-related serine/threonine protein kinase and plays an important role in normal cell cycle progression. However, its distribution and function in the central nervous system (CNS) lesion remain unclear. In this study, we mainly investigated the protein expression and cellular localization of CDK14 during spinal cord injury (SCI). Western blot analysis revealed that the expression of CDK14 was gradually increased and reached a peak at 3 days after SCI. The expression of CDK14 was further analyzed by immunohistochemistry. Double immunofluorescence staining showed that CDK14 was co-expressed prominent in astrocytes. Co-localization CDK14/proliferating cell nuclear antigen (PCNA) were detected in glial cells. cyclin Y, which can interact with CDK14, was detected that had same expression trend was consistent with CDK14 Western blot results in SCI. Double-immunofluorescence staining indicated that CDK14 co-expressed with cyclin Y in some cells. Co-immunoprecipitation had been showed that CDK14 could interact with cyclin Y after acute SCI. Taken together, these data suggested that both CDK14 and cyclin Y may play important roles in spinal cord pathophysiology.

High expression of ErbB3 binding protein 1 (EBP1) predicts poor prognosis of pancreatic ductal adenocarcinoma (PDAC).

Recent studies have identified that ErbB3 binding protein 1 (EBP1) is broadly expressed in various cancer tissues and critically involved in plenty of biological processes in this regard. However, the functional role of EBP1 in pancreatic ductal adenocarcinoma (PDAC) has never been elucidated. In this study, we found that EBP1 could serve as a prognostic biomarker of PDAC. Western blot analysis revealed that EBP1 was remarkably upregulated in PDAC tissues and cell lines. Using immunohistochemical analysis, we showed that the expression of EBP1 was correlated with tumor size (P = 0.004), histological differentiation (P = 0.041), and tumor node metastasis (TNM) stage (P = 0.000). Notably, Kaplan-Meier curve showed that high expression of EBP1 predicted significantly worsened prognosis of PDAC patients (P = 0.001). In addition, knockdown of EBP1 expression suppressed PDAC cell proliferation and retarded cell cycle progression. Furthermore, depletion of EBP1 induced the apoptosis of Panc-1 cells. Of great interest, we found that EBP1 interacted with anti-apoptotic protein, Bcl-xL, and promoted its accumulation. In summary, our results suggest that EBP1 is a novel prognostic indicator and potential therapeutic target of PDAC, shedding new insights into the important role of EBP1 in cancer development.

Up-regulation of VCAM1 Relates to Neuronal Apoptosis After Intracerebral Hemorrhage in Adult Rats.

Vascular cell adhesion molecule 1 (VCAM1) is a member of the Immunoglobulin superfamily and encodes a cell surface sialoglycoprotein expressed in cytokine-activated endothelium. This type I membrane protein mediates leukocyte-endothelial cell adhesion, facilitates the downstream signaling, and may play a role in the development of artherosclerosis and rheumatoid arthritis. Accumulating evidence has demonstrated that VCAM1 exerts an anti-apoptotic effect in several tumor tissues such as ovarian cancer and breast cancer. Intracerebral hemorrhage (ICH) is the second most common subtype of stroke with high morbidity and mortality, which imposes a big burden on individuals and the whole society. These together prompted us to question whether VCAM1 has some association with neuron apoptosis during the pathological process of ICH. An ICH rat model was established and assessed by behavioral tests in order to explore the role of VCAM1 after ICH. Up-regulation of VCAM1 was observed in brain areas surrounding the hematoma following ICH by western blotting and immunohistochemistry. Immunofluorescence manifested VCAM1 was strikingly increased in neurons, but not in astrocytes and microglia. Furthermore, we detected that neuronal apoptosis marker active caspase-3 had co-localizations with VCAM1. At the same time, Bcl-2 was also co-localized with VCAM1. Taken together, our findings suggested that VCAM1 might be involved in the neuronal apoptosis and pathophysiology of ICH.