Mutation of caspase-digestion sites in keratin 18 interferes with filament reorganization, and predisposes to hepatocyte necrosis and loss of membrane integrity

Weerasinghe, Sujith V. W.,Ku, Nam-On,Altshuler, Peter J.,Kwan, Raymond,Omary, M. Bishr The Company of Biologists Ltd. 2014 Journal of cell science Vol.127 No.7

<P>Keratin 18 (K18 or KRT18) undergoes caspase-mediated cleavage during apoptosis, the significance of which is poorly understood. Here, we mutated the two caspase-cleavage sites (D238E and D397E) in K18 (K18-DE), followed by transgenic overexpression of the resulting mutant. We found that K18-DE mice develop extensive Fas-mediated liver damage compared to wild-type mice overexpressing K18 (K18-WT). Fas-stimulation of K18-WT mice or isolated hepatocytes caused K18 degradation. By contrast, K18-DE livers or hepatocytes maintained intact keratins following Fas-stimulation, but showed hypo-phosphorylation at a major stress-kinase-related keratin 8 (K8) phosphorylation site. Although K18-WT and K18-DE hepatocytes showed similar Fas-mediated caspase activation, K18-DE hepatocytes were more ‘leaky’ after a mild hypoosmotic challenge and were more susceptible to necrosis after Fas-stimulation or severe hypoosmotic stress. K8 hypophosphorylation was not due to the inhibition of kinase binding to the keratin but was due to mutation-induced inaccessibility to the kinase that phosphorylates K8. A stress-modulated keratin phospho-mutant expressed in hepatocytes phenocopied the hepatocyte susceptibility to necrosis but was found to undergo keratin filament reorganization during apoptosis. Therefore, the caspase cleavage of keratins might promote keratin filament reorganization during apoptosis. Interference with keratin caspase cleavage shunts hepatocytes towards necrosis and increases liver injury through the inhibition of keratin phosphorylation. These findings might extend to other intermediate filament proteins that undergo proteolysis during apoptosis.</P>

Preventing Cooperative Black Hole Attacks in Mobile Ad Hoc Networks: Simulation Implementation and Evaluation

Hesiri Weerasinghe,Huirong Fu 보안공학연구지원센터 2008 International Journal of Software Engineering and Vol.2 No.3

A black hole attack is a severe attack that can be easily employed against routing in mobile ad hoc networks. A black hole is a malicious node that falsely replies for any route requests without having active route to specified destination and drops all the receiving packets. If these malicious nodes work together as a group then the damage will be very serious. This type of attack is called cooperative black hole attack. In [9], we proposed a solution to identifying and preventing the cooperative black hole attack. Our solution discovers the secure route between source and destination by identifying and isolating cooperative black hole nodes. In this paper, via simulation, we evaluate the proposed solution and compare it with other existing solutions in terms of throughput, packet loss percentage, average end-to-end delay and route request overhead. The experiments show that (1) the AODV greatly suffers from cooperative black holes in terms of throughput and packet losses, and (2) our solution proposed in [9] presents good performance in terms of better throughput rate and minimum packet loss percentage over other solutions, and (3) our solution proposed in [9] can accurately prevent the cooperative black hole attacks.

Single-step room temperature synthesis of vanadium oxide nanosheets for seawater/wastewater purification by photothermal evaporation under one sun illumination

Hemal Weerasinghe,Hui-Fen Wu 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.124 No.-

Vanadium dioxide has excellent absorbance in near-infrared (NIR) wavelengths making it a perfect candidatefor photothermal applications based on solar energy. However, up to date, it was mainly applied ina lithium-ion battery. This study is for the second time, to utilize VO2-based nanomaterials as a photothermalmaterial for solar steam generation to purify seawater and wastewater. The study has proposeda straightforward and promising room temperature approach to synthesize a mixture of twovanadium oxide nanosheets with a major fraction of VO2 (B) nanosheets with the major part for VO2. nH2O and a minor fraction of V2O5.nH2O which have demonstrated excellent photothermal capabilityfor water purification. The highest steady state temperature of 87 C was reported by the synthesizednanosheets that were spray coated on cellulose fabric for the solar absorption purpose under one sun illuminationfor water purification. The as-prepared photo absorber was capable of reaching the higheststeady temperature at high speed (within 10 minutes). The synthesized 2D VO2/V2O5.nH2O nanosheetsand cellulose fabric combination of solar steam generator gained a competitive evaporation rate of1.31 kgm-2h1 and a percentage efficiency of 89.7% under one sun illumination. The current approachwas successfully applied to three real-world samples to obtain clean or drinking water. All three samplesshowed excellent improvements in their water quality compared with their initial states in a single distillation. Two samples can even reach the quality of World Health Organization (WHO)-recommendedstandards for drinking water. The current approach has opened a new platform for the utilization ofVO2-based nanosheets for obtaining clean water from seawater and wastewater by solar energyutilization.

스리랑카의 가정에 필요한 빗물모으기 기술

( Aruni Weerasinghe ) 빗물학회 2002 빗물모으기운동 국제워크샵 Vol.2 No.-

Improving Web Service Recommendation using Clustering with K-NN and SVD Algorithms

( Amith M. Weerasinghe ),( Rupasingha A. H. M. Rupasingha ) 한국인터넷정보학회 2021 KSII Transactions on Internet and Information Syst Vol.15 No.5

In the advent of the twenty-first century, human beings began to closely interact with technology. Today, technology is developing, and as a result, the world wide web (www) has a very important place on the Internet and the significant task is fulfilled by Web services. A lot of Web services are available on the Internet and, therefore, it is difficult to find matching Web services among the available Web services. The recommendation systems can help in fixing this problem. In this paper, our observation was based on the recommended method such as the collaborative filtering (CF) technique which faces some failure from the data sparsity and the cold-start problems. To overcome these problems, we first applied an ontology-based clustering and then the k-nearest neighbor (KNN) algorithm for each separate cluster group that effectively increased the data density using the past user interests. Then, user ratings were predicted based on the model-based approach, such as singular value decomposition (SVD) and the predictions used for the recommendation. The evaluation results showed that our proposed approach has a less prediction error rate with high accuracy after analyzing the existing recommendation methods.

Acute MPTP treatment impairs dendritic spine density in the mouse hippocampus

Poornima D. E. Weerasinghe-Mud,Mary Jasmin Ang,Mai Wada,Sung-Ho Kim,Taekyun Shin,Miyoung Yang,Changjong Moon 한국실험동물학회 2021 한국실험동물학회 학술발표대회 논문집 Vol.2021 No.7

Among the animal models of Parkinson"s disease (PD), the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-lesioned mouse model has shown both dopaminergic (DA) damage and related motor control defects, as observed in patients with PD. Recent studies have suggested that the DA system interacts with the synaptic plasticity of the hippocampus in PD. However, little is known about how alterations in the hippocampal structural plasticity are affected by the DA damage in MPTP-lesioned models. In the present study, we investigated alterations in dendritic complexity and spine density in the mouse hippocampus following acute MPTP treatment (22 mg/kg, i.p., four times/day, 2-h intervals). We confirmed that acute MPTP treatment significantly decreased initial motor function and reduced persistently the number of tyrosine hydroxylase-positive DA neurons in the substantia nigra. Golgi staining showed that acute MPTP treatment significantly reduced the spine density of neuronal dendrites in the cornu ammonis 1 (CA1) apical/basal and dentate gyrus (DG) subregions of the mouse hippocampus at 8 and 16 days after treatment, although it did not affect dendritic complexity (e.g., number of crossing dendrites, total dendritic length, and branch points per neuron) in both CA1 and DG subregions at all time points after treatment. Therefore, the present study provides anatomical evidence that acute MPTP treatment affects synaptic structure in the hippocampus during the late phase after acute MPTP treatment in mice, independent of any changes in the dendritic arborization of hippocampal neurons. These findings offer data for the ability of the acute MPTP-lesioned mouse model to replicate the non-nigrostriatal lesions of clinical PD.

Impact of diesel particulate matter on the olfactory bulb of mice: insights from behavioral, histological, and molecular assessments

이정민,Weerasinghe-Mudiyanselage Poornima D. E.,Kim Bohye,Kang Sohi,Kim Joong-Sun,Moon Changjong 대한독성 유전단백체 학회 2024 Molecular & cellular toxicology Vol.20 No.3

Background Diesel particulate matter (DPM) constitutes a significant air pollutant that adversely affects neurological health through the olfactory pathway. Although extensive human epidemiological and animal research exists, the specific mechanisms underlying DPM-induced olfactory dysfunction have not been definitively elucidated. Objective This study aimed to conduct a comprehensive analysis of the behavioral, histological, and molecular changes in the olfactory bulb (OB) of mice following intranasal exposure to 10 mg/kg DPM for a duration of four weeks. Results Exposure to DPM led to notable olfactory impairment in the mice, characterized by an elevation in Iba-1-positive microglia, though without inducing neuronal cell death. Transcriptomic evaluation revealed 84 differentially expressed genes (DEGs) in the OB that met the criteria of fold change greater than 1.5 and a p value less than 0.05. Within this set, 55 genes were upregulated and 29 were downregulated. Gene ontology-based functional analysis revealed that these DEGs were primarily related to sensory organ morphogenesis, energy homeostasis, and the regulation of monocyte aggregation. Subsequent investigation using the Kyoto Encyclopedia of Genes and Genomes database identified enriched pathways connected to neuroactive ligand-receptor interactions and calcium signaling. Conclusion Our findings suggest a plausible association between DPM-induced olfactory dysfunction and disruptions in a range of molecular pathways. This hypothesis is supported by observed alterations in gene expression and the presence of mild neuroinflammation, primarily driven by microglial activation. Background Diesel particulate matter (DPM) constitutes a significant air pollutant that adversely affects neurological health through the olfactory pathway. Although extensive human epidemiological and animal research exists, the specific mechanisms underlying DPM-induced olfactory dysfunction have not been definitively elucidated. Objective This study aimed to conduct a comprehensive analysis of the behavioral, histological, and molecular changes in the olfactory bulb (OB) of mice following intranasal exposure to 10 mg/kg DPM for a duration of four weeks. Results Exposure to DPM led to notable olfactory impairment in the mice, characterized by an elevation in Iba-1-positive microglia, though without inducing neuronal cell death. Transcriptomic evaluation revealed 84 differentially expressed genes (DEGs) in the OB that met the criteria of fold change greater than 1.5 and a p value less than 0.05. Within this set, 55 genes were upregulated and 29 were downregulated. Gene ontology-based functional analysis revealed that these DEGs were primarily related to sensory organ morphogenesis, energy homeostasis, and the regulation of monocyte aggregation. Subsequent investigation using the Kyoto Encyclopedia of Genes and Genomes database identified enriched pathways connected to neuroactive ligand-receptor interactions and calcium signaling. Conclusion Our findings suggest a plausible association between DPM-induced olfactory dysfunction and disruptions in a range of molecular pathways. This hypothesis is supported by observed alterations in gene expression and the presence of mild neuroinflammation, primarily driven by microglial activation.

Investigation of a Pseudo Capacitor with Polyacrylonitrile based Gel Polymer Electrolyte

Harankahawa, Neminda,Weerasinghe, Sandaranghe,Vidanapathirana, Kamal,Perera, Kumudu The Korean Electrochemical Society 2017 Journal of electrochemical science and technology Vol.8 No.2

Pseudo capacitors belong to one group of super capacitors which are consisted with non carbon based electrodes. As such, conducting polymers and metal oxide materials have been employed for pseudo capacitors. Conducting polymer based pseudo capacitors have received a great attention due to their interesting features such as flexibility, low cost and ease of synthesis. Much work has been done using liquid electrolytes for those pseudo capacitors but has undergone various drawbacks. It has now been realized the use of solid polymer electrolytes as an alternative. Among them gel polymer electrolytes (GPEs) are in a key place due to their high ambient temperature conductivities as well as suitable mechanical properties. In this study, composition of a polyacrylonitrile (PAN) based GPE was optimized and it was employed as the electrolyte in a pseudo capacitor having polypyrrole (PPy) electrodes. GPE was prepared using ethylene carbonate (EC), propylene carbonate (PC), sodium thiocyanate (NaSCN) and PAN as starting materials. The maximum room temperature conductivity of the GPE was $1.92{\times}10^{-3}Scm^{-1}$ for the composition 202.5 PAN : 500 EC : 500 PC : 35 NaSCN (by weight). Performance of the pseudo capacitor was investigated using Cyclic Voltammetry technique, Electrochemical Impedance Spectroscopy (EIS) technique and Continuous Charge Discharge (GCD) test. The single electrode specific capacity (Cs) was found out to be 174.31 F/g using Cyclic Voltammetry technique at the scan rate of 10 mV/s and within the potential window -1.2 V to 1.2 V. The same value obtained using EIS was about 84 F/g. The discharge capacity ($C_d$) was 69.8 F/g. The capacity fade over 1000 cycles was rather a low value of 4%. The results proved the suitability of the pseudo capacitor for improving the performance further.

Effects of supplementation of urea-molasses multinutrient block (UMMB) on the performance of dairy cows fed good quality forage based diets with rice straw as a night feeding

Jayawickrama, Dona R.,Weerasinghe, Piyatilak B.,Jayasena, Dinesh D.,Mudannayake, Deshani C. Institute of Agricultural Science 2013 Korean Journal of Agricultural Science Vol.40 No.2

An experiment was conducted to evaluate the effects of nitrogen supplementation through urea-molasses multinutrient block (UMMB) on the performance of dairy cows fed good quality forage based diets with rice straw as a night feeding. A total of 10 multiparous crossbred dairy cows in their early lactation were grouped into two categories based on their breed, parity, body weight, milk yield, milk fat and protein contents and daily fed a chopped CO-3 grass (Pennisetum purpureum ${\times}$ Pennisetum americanum; hybrid Napier) ad-libitum, 1 kg of dairy cow concentrate feed during the day time and 5 kg of rice straw (dry matter basis) at night as the basal diet (control) for 5 wk. In addition to the basal diet, the treatment group received 300 g of crushed UMMB daily throughout the experimental period. Cows were milked twice daily and the milk yields were recorded. Milk and feed samples were collected weekly for chemical analysis. Supplementation of UMMB had no significant effects (p>0.05) on straw intake, daily milk yield, contents and yields of milk constituents such as milk fat, protein, lactose and solids-non-fat. In addition, milk urea nitrogen content were not affected (p>0.05) by UMMB supplementation. However, numerical increments in all the parameters measured were observed during the study in cows fed diets supplemented with UMMB. It can be concluded that nitrogen supplied through UMMB had no effects on production performances of dairy cows in this study.

Changes in the Neuronal Architecture of the Hippocampus in a 6-Hydroxydopamine-Lesioned Rat Model of Parkinson Disease

김보혜,Poornima D. E. Weerasinghe-Mudiyanselage,Mary Jasmin Ang,이정민,강소희,김종춘,김성호,김중선,정채용,신태균,문창종 대한배뇨장애요실금학회 2022 International Neurourology Journal Vol.26 No.S2

Purpose: Parkinson disease (PD) is a progressive neurodegenerative disorder in which dopaminergic (DAergic) systems are destroyed (particularly in the nigrostriatal system), causing both motor and nonmotor symptoms. Hippocampal neuroplasticity is altered in PD animal models, resulting in nonmotor dysfunctions. However, little is known about the precise mechanism underlying the hippocampal dysfunctions in PD. Methods: Striatal 6-hydroxydopamine (6-OHDA) infusions were performed unilaterally in adult Sprague Dawley rats. Both motor and nonmotor symptoms alongside the expression of tyrosine hydroxylase (TH) in the substantia nigra and striatum were confirmed in 6-OHDA-lesioned rats. The neuronal architecture in the hippocampus was analyzed by Golgi staining. Results: During the 7–8 weeks after infusion, the 6-OHDA-lesioned rats exhibited motor and nonmotor dysfunctions (especially anxiety/depression-like behaviors). Rats with unilateral 6-OHDA infusion displayed reduced TH+ immunoreactivity in the ipsilateral nigrostriatal pathway of the brain. Golgi staining revealed that striatal 6-OHDA infusion significantly decreased the dendritic complexity (i.e., number of crossing dendrites, total dendritic length, and branch points) in the ipsilateral hippocampal conus ammonis 1 (CA1) apical/basal and dentate gyrus (DG) subregions. Additionally, the dendritic spine density and morphology were significantly altered in the CA1 apical/basal and DG subregions following striatal 6-OHDA infusion. However, alteration of microglial and astrocytic distributions did not occur in the hippocampus following striatal 6-OHDA infusion. Conclusions: The present study provides anatomical evidence that the structural plasticity in the hippocampus is altered in the late phase following striatal 6-OHDA infusion in rats, possibly as a result of the prolonged suppression of the DAergic system, and independent of neuroinflammation.