Oxygen-glucose deprivation and interleukin-1α trigger the release of perlecan LG3 by cells of neurovascular unit

[Image: see text] Two of the main stresses faced by cells at the NVU as an immediate result of cerebral ischemia are oxygen-glucose deprivation (OGD)/reperfusion and inflammatory stress caused by up regulation of IL-1. As a result of these stresses, perlecan, an important component of the NVU extracellular matrix (ECM), is highly proteolyzed. Here we describe that focal cerebral ischemia in rats results in increased generation of LG3, the c-terminal bioactive fragment of perlecan. Further, in vitro study of the cells of the NVU was performed to locate the source of this increased perlecan-LG3. Neurons, astrocytes, brain endothelial cells and pericytes were exposed to OGD/reperfusion and IL-1α/β. It was observed that neurons and pericytes showed increased levels of LG3 during OGD in their culture media. During in vitro reperfusion, neurons, astrocytes and pericytes showed elevated levels of LG3, but only after exposure to brief durations of OGD. IL-1α and IL-1β treatment tended to have opposite effects on NVU cells. While IL-1α increased or had minimal to no effect on LG3 generation, high concentrations of IL-1β decreased it in most cells studied. Finally, LG3 was determined to be neuroprotective and anti-proliferative in brain endothelial cells, suggesting a possible role for the generation of LG3 in the ischemic brain

Arhgef16, a novel Elmo1 binding partner, promotes clearance of apoptotic cells via RhoG-dependent Rac1 activation

AbstractElmo is an evolutionarily conserved mammalian ortholog of Caenorhabditis elegans CED-12 with proposed roles during the removal of apoptotic cells, cell migration, neurite outgrowth, and myoblast fusion (Katoh and Negishi (2003) [1], Park and Tosello (2007) [2], Grimsley et al. (2004) [3], Hamoud et al. (2014) [4]). Elmo mediates these cellular processes by interacting with various proteins located in the plasma membrane, cytoplasm and nucleus, and by modulating their activities although it has no intrinsic catalytic activity (Park and Tosello (2007) [2], Hamoud et al. (2014) [4], Li et al. (2013) [5], Margaron, Fradet and Cote (2013) [6], and Mauldin et al. (2013)[7]). Because there are a limited number of proteins known to interact with Elmo, we performed a yeast two-hybrid screen using Elmo1 as bait to identify Elmo1-interacting proteins and to evaluate their mode of regulation. Arhgef16 was one of the proteins identified through the screen and subsequent analyses revealed that Arhgef16 interacted with Elmo1 in mammalian cells as well. Expression of Arhgef16 in phagocytes promoted engulfment of apoptotic cells, and engulfment mediated by Arhgef16 increased synergistically in the presence of Elmo1 but was abrogated in the absence of Elmo1. In addition, Arhgef16-mediated removal of apoptotic cells was dependent on RhoG, but independent of Dock1. Taken together, this study suggests that the newly identified Elmo1-interacting protein, Arhgef16, functions synergistically with Elmo1 to promote clearance of apoptotic cells in a RhoG-dependent and Dock1-independent manner

Perlecan Domain V induces VEGf secretion in brain endothelial cells through integrin α5β1 and ERK-dependent signaling pathways.

Perlecan Domain V (DV) promotes brain angiogenesis by inducing VEGF release from brain endothelial cells (BECs) following stroke. In this study, we define the specific mechanism of DV interaction with the α(5)β(1) integrin, identify the downstream signal transduction pathway, and further investigate the functional significance of resultant VEGF release. Interestingly, we found that the LG3 portion of DV, which has been suggested to possess most of DV\u27s angio-modulatory activity outside of the brain, binds poorly to α(5)β(1) and induces less BEC proliferation compared to full length DV. Additionally, we implicate DV\u27s DGR sequence as an important element for the interaction of DV with α(5)β(1). Furthermore, we investigated the importance of AKT and ERK signaling in DV-induced VEGF expression and secretion. We show that DV increases the phosphorylation of ERK, which leads to subsequent activation and stabilization of eIF4E and HIF-1α. Inhibition of ERK activity by U0126 suppressed DV-induced expression and secretion of VEGR in BECs. While DV was capable of phosphorylating AKT we show that AKT phosphorylation does not play a role in DV\u27s induction of VEGF expression or secretion using two separate inhibitors, LY294002 and Akt IV. Lastly, we demonstrate that VEGF activity is critical for DV increases in BEC proliferation, as well as angiogenesis in a BEC-neuronal co-culture system. Collectively, our findings expand our understanding of DV\u27s mechanism of action on BECs, and further support its potential as a novel stroke therapy

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Department of Biological SciencesRAD51 is one of the major players in homologous recombination (HR) for repairing double-strand breaks (DSBs) and also protects replication forks (RFs) for genome maintenance to suppress tumors. RAD51 should be tightly regulated by post-translational modifications (PTMs) or protein-protein interactions to prevent unscheduled HR. c-Abl tyrosine kinase sequentially phosphorylates RAD51 at Y315 and Y54 in response to ionizing radiation (IR). However, the functional significance of these phosphorylations remained elusive. In leukemia cells, BCR-ABL, oncogenic tyrosine kinase constitutively phosphorylates RAD51, but it is unclear what the consequence of such constitutive phosphorylation is in leukemic cells and its impact on genome maintenance or potentially in tumor progression and drug resistance. In this study, Rad51 knock-in (KI) mouse embryonic stem (ES) cell lines and Rad51 Y315F genetically-modified mouse were analyzed to define the roles of Rad51 tyrosine phosphorylation in vivo. I found the followings: 1) RAD51 Y315 residue is phosphorylated by BCRABL in cells 2) the Y54 phosphorylation of RAD51 significantly reduced the formation of IR-induced eGFP-hRAD51 foci (HR defect) 3) Phosphorylation of RAD51 impaired RAD51 self-interaction 4) Overexpression of either RAD51 Y54E or Y315E decreased I-SceI induced DSB repair 5) Rad51 Y315F knock-in mouse increased genomic instability in response to low-dose IR. Taken together, RAD51 tyrosine phosphorylations play roles in DSB repair to maintain genomic integrity.clos

LI-RADS Category Can Be a Post-Surgical Prognostic Factor for Intrahepatic Cholangiocarcinoma in Patients with Liver Cirrhosis or Chronic Hepatitis B

Introduction: The Liver Imaging Reporting and Data System (LI-RADS) categorization has been proposed as a potential prognostic indicator for primary liver neoplasms in patients with liver cirrhosis or chronic hepatitis B. This multicenter study aimed to determine whether LI-RADS categorization can offer additional post-surgical prognostic value for intrahepatic cholangiocarcinoma (ICCA) when used in conjunction with the American Joint Committee on Cancer (AJCC) guidelines. Methods: Patients with high risk for hepatocellular carcinoma, surgically confirmed ICCAs, and available preoperative MRI were enrolled. LI-RADS categorization of ICCAs was performed using MRI features, and multivariate analyses were conducted incorporating LI-RADS category, AJCC staging, and clinicopathologic factors to evaluate their predictive value for postoperative recurrence-free survival (RFS) and overall survival (OS). In patients with early recurrence (<2 years), the percentages of AJCC stage I and LR-M or LR tumor-in-vein (TIV) were calculated, respectively. Results: Among the 166 ICCAs analyzed, 13.3% (22/166) were classified as LR-4/5, 77.7% (129/166) as LR-M, and 9.0% (15/166) as LR TIV. Classifications according to the 8th AJCC guidelines for patients with available post-surgical pathologic data and follow-up imaging were 40.6% (63/155) stage I tumors, 23.9% (37/155) stage II, and 35.5% (55/155) stage III. Multivariate analysis revealed that LI-RADS category (LR-M or LR-TIV) was a significant factor for predicting both RFS (hazard ratio [HR] = 2.86, p = 0.02) and OS (HR = 3.18, p = 0.03). Additionally, AJCC staging (II or III) was a significant factor for RFS (HR = 3.90, p < 0.001) and OS (HR = 3.29, p < 0.001), male sex was a significant factor for RFS (HR = 1.89, p = 0.006) and OS (HR = 2.23, p = 0.002), and positive resection margin was a significant factor for OS (HR = 1.91, p = 0.03). Among the 80 patients with early recurrence, 97.5% displayed LR-M or LR-TIV features, while 11.3% were AJCC stage I patients. Conclusion: The MRI-based preoperative LI-RADS categorization of ICCA provides additional post-surgical prognostic value beyond the AJCC guidelines, with significant implications for both RFS and OS

Optimizing Operating Parameters of Electric Ultra-Low Volume Sprayer with Slightly Acidic Electrolyzed Solution for Efficient Virucidal Activity on Environmental Surfaces

Recently, and considering the COVID-19 pandemic, there has been a growing consensus that the disinfection of surfaces contaminated with pathogenic viral particles is essential. Chemical disinfectant sprays are effective at preventing the spread of infectious human noroviruses (Hu-NoVs) in healthcare and public areas. We assessed the virucidal activity of slightly acidic electrolyzed water (SAEW) spray on fomite surfaces. A multivariate statistical assessment that combined a response surface methodology (RSM) and a Box–Behnken design (BBD) was performed to define the optimal parameters of, and correlations among, experimental conditions. Spraying SAEW disinfectant (oxidation-reduction potential: 1123 mV, pH range: 5.12, available chlorine concentration: 33.22 ppm) resulted in the successful decontamination of Hu-NoV, with a 4-log reduction in viral particles on polyvinyl chloride, stainless steel, ceramic tile, and glass surfaces. Our experimental data revealed optimized treatment conditions for decontaminating Hu-NoV GI.6 and GII.4, using the numerical multiple optimized method (spraying rate: 218 mL/min, spraying time: 4.9 s, spraying distance: 0.9 m). These findings offer significant insights for designing optimal strategic control practices to prevent infectious disease, particularly Hu-NoV, transmission

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, Manho Lee 1, Jaegwan Park 1, Jaeseung G

Current Understanding of Methamphetamine-Associated Metabolic Changes Revealed by the Metabolomics Approach

Metabolomics is a powerful tool used in the description of metabolic system perturbations caused by diseases or abnormal conditions, and it usually involves qualitative and/or quantitative metabolome determination, accompanied by bioinformatics assessment. Methamphetamine is a psychostimulant with serious abuse potential and due to the absence of effective pharmacotherapy and a high recurrence potential, methamphetamine addiction is a grave issue. Moreover, its addiction mechanisms remain unclear, probably due to the lack of experimental models that reflect personal genetic variances and environmental factors determining drug addiction occurrence. The metabolic approach is only recently being used to study the metabolic effects induced by a variety of methamphetamine exposure statuses, in order to investigate metabolic disturbances related to the adverse effects and discover potential methamphetamine addiction biomarkers. To provide a critical overview of methamphetamine-associated metabolic changes revealed in recent years using the metabolomics approach, we discussed methamphetamine toxicity, applications of metabolomics in drug abuse and addiction studies, biological samples used in metabolomics, and previous studies on metabolic alterations in a variety of biological samples—including the brain, hair, serum, plasma, and urine—following methamphetamine exposure in animal studies. Metabolic alterations observed in animal brain and other biological samples after methamphetamine exposure were associated with neuronal and energy metabolism disruptions. This review highlights the significance of further metabolomics studies in the area of methamphetamine addiction research. These findings will contribute to a better understanding of metabolic changes induced by methamphetamine addiction progress and to the design of further studies targeting the discovery of methamphetamine addiction biomarkers and therapeutic targets