Efficient adsorption of chromium ions from aqueous solutions by plant-derived silica

Nowadays, there is great interest in the use of plant waste to obtain materials for environmental protection. In this study, silica powders were prepared with a simple and low-cost procedure from biomass materials such as horsetail and common reed, as well as wheat and rye straws. The starting biomass materials were leached in a boiling HCl solution. After washing and drying, the samples were incinerated at 700 degrees C for 1 h in air. The organic components of the samples were burned leaving final white powders. These powders were characterized by powder X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, dynamic light scattering (DLS), scanning electron microscopy (SEM), and low-temperature nitrogen sorption. The amorphous powders (biosilica) contained mainly SiO2, as indicated by FTIR analysis. Horsetail-derived silica was chosen for testing the removal of dichromate ions from water solutions. This biosilica had a good ability to adsorb Cr(VI) ions, which increased after modification of the powder with the dodecylamine surfactant. It can be concluded that the applied procedure allowed obtaining high purity biosilica from plant waste with good efficiency. The produced biosilica was helpful in removing chromium ions and showed low cytotoxicity to human endothelial cells, suggesting that it can be safely used in environmental remediation

RIPK4 downregulation impairs Wnt3A-stimulated invasiveness via Wnt/β\beta-catenin signaling in melanoma cells and tumor growth in vivo

Purpose The role of Wnt signaling in oncogenesis and drug resistance is well known. Receptor-interacting protein kinase (RIPK4) contributing to the increased activity of many signaling pathways, including Wnt/$\beta$-catenin, may be an important target for designing new drugs for metastatic melanoma, but its role in melanoma is not fully understood. Methods We tested the effect of genetic manipulation of RIPK4 (CRISPR/Cas9) on xenograft growth. In addition, immunohistochemistry was used to detect active $\beta$-catenin, Ki67 and necrosis in xenografts. Wnt signaling pathway activity was examined using Western blot and Top-Flash. The effect of RIPK4 knockout on melanoma cells in vitro stimulated Wnt3A on wound overgrowth, migration and invasion ability was then evaluated. Results Our study showed that CRISPR/Cas9-mediated RIPK4 knockout (KO) significantly reduced tumor growth in a mouse model of melanoma, particularly of WM266.4 cells. RIPK4 KO tumors exhibited lower percentages of $Ki67^{+}$ cells as well as reduced necrotic area and decreased levels of active $\beta$-catenin. In addition, we observed that RIPK4 knockout impaired Wnt3A-induced activation of LRP6 and $\beta$-catenin, as manifested by a decrease in the transcriptional activity of $\beta$-catenin in Top-Flash in both tested melanoma cell lines, A375 and WM266.4. Prolonged incubation (48 h) with Wnt3A showed reduced level of MMP9, C-myc, and increased SOX10, proteins whose transcription is also dependent on $\beta$-catenin activity. Moreover, RIPK4 knockout led to the inhibition of scratch overgrowth, migration and invasion of these cells compared to their controls. Conclusion RIPK4 knockdown inhibits melanoma tumor growth and Wnt3A stimulated migration and invasion indicating that RIPK4 might be a potential target for melanoma therapy

Vemurafenib and dabrafenib downregulates RIPK4 level

Vemurafenib and dabrafenib are BRAF kinase inhibitors (BRAFi) used for the treatment of patients with melanoma carrying the V600E BRAF mutation. However, melanoma cells develop resistance to both drugs when used as monotherapy. Therefore, mechanisms of drug resistance are investigated, and new molecular targets are sought that could completely inhibit melanoma progression. Since receptor-interacting protein kinase (RIPK4) probably functions as an oncogene in melanoma and its structure is similar to the BRAF protein, we analyzed the impact of vemurafenib and dabrafenib on RIPK4 in melanomas. The in silico study confirmed the high similarity of BRAF kinase domains to the RIPK4 protein at both the sequence and structural levels and suggests that BRAFi could directly bind to RIPK4 even more strongly than to ATP. Furthermore, BRAFi inhibited ERK1/2 activity and lowered RIPK4 protein levels in BRAF-mutated melanoma cells (A375 and WM266.4), while in wild-type BRAF cells (BLM and LoVo), both inhibitors decreased the level of RIPK4 and enhanced ERK1/2 activity. The phosphorylation of phosphatidylethanolamine binding protein 1 (PEBP1) - a suppressor of the BRAF/MEK/ERK pathway - via RIPK4 observed in pancreatic cancer did not occur in melanoma. Neither downregulation nor upregulation of RIPK4 in BRAF- mutated cells affected PEBP1 levels or the BRAF/MEK/ERK pathway. The downregulation of RIPK4 inhibited cell proliferation and the FAK/AKT pathway, and increased BRAFi efficiency in WM266.4 cells. However, the silencing of RIPK4 did not induce apoptosis or necroptosis. Our study suggests that RIPK4 may be an off-target for BRAF inhibitors

Nanosilica from biomass – characteristics, toxicity in relation to eukaryoticcells and bioanalyticalapplication

Zainteresowanie biomasą, jako surowcem do produkcji nanocząstek jest tematem aktualnych badań. W niniejszej pracy sprawdzono możliwość zastosowania nanocząstek krzemionki wytworzonych z biomasy Equisetum arvense L. oraz oceniono ich toksyczność względem komórek śródbłonka ludzkiego. Uzyskany nanoproszek krzemionki został rozdzielony na dwie frakcje różniące się rozmiarami cząstek. Określono wartości EC50 dla toksyczności dwóch frakcji nanocząstek względem komórek śródbłonka. Preparat zawierający cząstki charakteryzujące się rozmiarem rzędu 500 nm został wykorzystany do określenia poziomu adsorpcji metali ciężkich na przykładzie jonów dichromianu. Powierzchnia nanocząstek została również zmodyfikowana przy pomocy surfaktantu dodecyloaminy, co doprowadziło do zwiększenia właściwości adsorpcyjnych nanokrzemionki. Przedstawione wyniki pozwalają sugerować, że nanoproszek krzemionki uzyskany z biomasy Equisetum arvense L. charakteryzuje się niską toksycznością i mógłby znaleźć zastosowanie w zakresie oczyszczania środowiska, między innymi z ciężkich metali.There is an increasing interest in biomass as a raw material for the production of nanoparticles. In this study, the possibility of application of silica nanoparticles obtained from Equisetum arvense L. biomass was checked. The nanomaterial cytotoxicity in relation to endothelial cells was also evaluated. The obtained silica nanoparticles were separated into two fractions differing in size. The EC50 values for both nanoparticle fractions were determined. Nanopowder fraction containing particles characterized by a size of 500 nm was used to determine the level of adsorption of heavy metals, e.i. dichromate ions. The nanoparticle surface was modified using dodecylamine, resulting in increased adsorption properties of the nanosilica. The results suggest that the obtained silica nanopowders from the biomass of Equisetum arvense L. are characterized by low toxicity and could be helpful in environmental protection, among others for the disposal of heavy metals

The role of short isoform of the dopaminergic receptor 2 in inflammatory processes in a human neuronal cell model

Liczne doniesienia sugerują, że występowanie niekontrolowanego stanu zapalnego w tkance nerwowej może prowadzić do stopniowej dysfunkcji neuronów, a w konsekwencji do rozwoju chorób neurodegeneracyjnych. Wykazano, że takie choroby jak PD, AD czy też choroba Huntingtona są regulowane poprzez sygnalizację dopaminergiczną, m. in. za pośrednictwem receptora dopaminergicznego typu 2. Receptor ten występuje w dwóch izoformach – krótkiej i długiej – różniących się dodatkową sekwencją 29 aminokwasów w trzeciej wewnątrzkomórkowej pętli izoformy długiej. Odmienna struktura, a także lokalizacja obu izoform rodzi pytanie, czy obie izoformy podobnie wpływają na sygnalizację komórkową pochodzącą od receptora D2 w momencie indukcji stanu zapalnego. Celem niniejszej pracy było poznanie roli krótkiej izoformy receptora D2 w stanach zapalnych w ludzkim modelu komórek neuronalnych.W badaniach wykorzystano komórki ludzkiej linii neuroblastoma SH-SY5Y, a także komórki linii neuroblastoma SH-SY5Y wykazujące wzmożoną ekspresję D2RS po stymulacji doksycykliną. Oba rodzaje komórek różnicowano kwasem retinowym w celu otrzymania modelu komórek neuronalnych. W przeprowadzanych badaniach sprawdzono ekspresję mRNA genów wybranych cytokin prozapalnych oraz ich stężenia po indukcji stanu zapalnego przy pomocy czynnika martwicy nowotworów oraz po aktywacji receptora D2 specyficznym agonistą. Ponadto sprawdzono również poziom aktywacji wybranych białek związanych z sygnalizacją komórkową.Wśród najważniejszych obserwacji należy wymienić hamowanie produkcji cytokin prozapalnych w modelu komórkowym wykazującym wzmożoną ekspresję D2RS po wywołaniu stanu zapalnego. Ponadto, wykazano, że klasyczne szlaki sygnałowe, takie jak STAT3, NFκB i Akt mogą być zaangażowane w tę odpowiedź. Przedstawione wyniki pozwalają sugerować, że obserwowane działanie przeciwzapalne może mieć miejsce za sprawą aktywacji D2RS i otwierają nowy trend w szukaniu specyficznych agonistów tej izoformy, którzy mogą mieć wysoki potencjał terapeutyczny w wielu chorobach zapalnych układu nerwowego.Numerous reports suggest that the occurrence of uncontrolled inflammation in the nervous tissues may lead to a gradual dysfunction of neurons and, consequently, to the development of neurodegeneration. Diseases such as PD, AD and Huntington's disease have been shown to be regulated by dopaminergic signaling, that is mediated by the type 2 dopaminergic receptor. This receptor has two isoforms – short and long – differing by an additional sequence of 29 aminoacids in the third intra-cellular loop of D2RL. Difference in structure, as well as in localisation of these isoforms raises the question if both isoforms can activate the cell signaling in the same way under inflammatory insults. The aim of this study was to investigate the role of the D2 receptor short isoform in inflammation in the human model of neuronal cells.Human neuroblastoma cells SH-SY5Y and SH-SY5Y neuroblastoma cells showing increased expression of D2RS after stimulation with doxycycline were used in the research. Both cell types were differentiated with retinoic acid to obtain neuron-like models. In this study, mRNA and protein expression of selected pro-inflammatory cytokine after TNF-α-induced inflammation and after D2 receptor with a specific agonist was checked. In addition, the activation level of selected proteins related to cell signaling was also analyzed.The most important observations include the pro-inflammatory cytokine inhibition in the neuronal model showing increased expression of D2RS after induction of inflammation. Moreover, it has been shown that classical signaling pathways such as STAT3, NFκB and Akt can be involved in this response. The presented results suggest that the observed anti-inflammatory effect may be due to D2RS activation and open a new trend in the search for specific agonists of this isoform, which may have high therapeutic potential in many inflammatory diseases of the nervous system