Intracellular Quantum Sensing of Free-Radical Generation Induced by Acetaminophen (APAP) in the Cytosol, in Mitochondria and the Nucleus of Macrophages

Acetaminophen overdoses cause cell injury in the liver. It is widely accepted that liver toxicity is initiated by the reactive N-acetyl-para-aminophenol (APAP) metabolite N-acetyl-p-benzoquinone imine (NAPQI), which first depletes glutathione and then irreversibly binds to mitochondrial proteins and nuclear DNA. As a consequence, mitochondrial respiration is inhibited, and DNA strands break. NAPQI also promotes the oxidative stress since glutathione is one of the main free-radical scavengers in the cell. However, so far it is unknown where exactly free radicals are generated. In this study, we used relaxometry, a novel technique that allows nanoscale magnetic resonance imaging detection of free radicals. The method is based on fluorescent nanodiamonds, which change their optical properties based on their magnetic surrounding. To achieve subcellular resolution, these nanodiamonds were targeted to cellular locations, that is, the cytoplasm, mitochondria, and the nucleus. Since relaxometry is sensitive to spin noise from radicals, we were able to measure the radical load in these different organelles. For the first time, we measured APAP-induced free-radical production in an organelle-specific manner, which helps predict and better understand cellular toxicity.

Fluorescent Nanodiamonds for Detecting Free-Radical Generation in Real Time during Shear Stress in Human Umbilical Vein Endothelial Cells

Free-radical generation is suspected to play a key role in cardiovascular diseases. Another crucial factor is shear stress. Human umbilical vein endothelial cells (HUVECS), which form the lining of blood vessels, require a physiological shear stress to activate many vasoactive factors. These are needed for maintaining vascular cell functions such as nonthrombogenicity, regulation of blood flow, and vascular tone. Additionally, blood clots form at regions of high shear stress within a blood vessel. Here, we use a new method called diamond magnetometry which allows us to measure the dynamics of free-radical generation in real time under shear stress. This quantum sensing technique allows free-radical detection with nanoscale resolution at the single-cell level. We investigate radical formation in HUVECs in a microfluidic environment under different flow conditions typically found in veins and arteries. Here, we looked into free-radical formation before, during, and after flow. We found that the free-radical production varied depending on the flow conditions. To confirm the magnetometry results and to differentiate between radicals, we performed conventional fluorescent reactive oxygen species (ROS) assays specific for superoxide, nitric oxide, and overall ROS.

Unfolding the apoptotic mechanism of antioxidant enriched-leaves of Tabebuia pallida (lindl.) miers in EAC cells and mouse model

ETHNOPHARMACOLOGICAL RELEVANCE

Tabebuia pallida (Lindl.) Miers (T. pallida) is a well-known native Caribbean medicinal plant. The leaves and barks of T. pallida are used as traditional medicine in the form of herbal or medicinal tea to manage cancer, fever, and pain. Moreover, extracts from the leaves of T. pallida showed anticancer activity. However, the chemical profile and mechanism of anticancer activity of T. pallida leaves (TPL), stem bark (TPSB), root bark (TPRB) and flowers (TPF) remain unexplored.

AIM OF THE STUDY

The present study was designed to explore the regulation of apoptosis by T. pallida using Ehrlich Ascites Carcinoma (EAC) cultured cells and an EAC mouse model. LC-ESI-MS/MS was used for compositional analysis of T. pallida extracts.

MATERIALS AND METHODS

Dried and powdered TPL, TPSB, TPRB and TPF were extracted with 80% methanol. Using cultured EAC cells and EAC-bearing mice with and without these extracts, anticancer activities were studied by assessing cytotoxicity and tumor cell growth inhibition, changes in life span of mice, and hematological and biochemical parameters. Apoptosis was analyzed by microscopy and expression of selected apoptosis-related genes (Bcl-2, Bcl-xL, NFκ-B, PARP-1, p53, Bax, caspase-3 and -8) using RT-PCR. LC-ESI-MS analysis was performed to identify the major compounds from active extracts. Computer aided analyses was undertaken to sort out the best-fit phytoconstituent of total ten isolated compounds of this plant for antioxidant and anticancer activity.

RESULTS

In EAC mice compared with untreated controls, the TPL extract exhibited the highest cancer cell toxicity with significant tumor cell growth inhibition (p < 0.001), reduced ascites by body weight (p < 0.01), increased the life span (p < 0.001), normalized blood parameters (RBC/WBC counts), and increased the levels of superoxide dismutase and catalase. TPL-treated EAC cells showed increased apoptotic characteristics of membrane blebbing, chromatin condensation and nuclear fragmentation, and caspase-3 activation, compared with untreated EAC cells. Moreover, annexin V-FITC and propidium iodide signals were greatly enhanced in response to TPL treatment, indicating apoptosis induction. Pro- and anti-apoptotic signaling after TPL treatment demonstrated up-regulated p53, Bax and PARP-1, and down-regulated NFκ-B, Bcl-2 and Bcl-xL expression, suggesting that TPL shifts the balance of pro- and anti-apoptotic genes towards cell death. LC-ESI-MS data of TPL showed a mixture of glycosides, lapachol, and quercetin antioxidant and its derivatives that were significantly linked to cancer cell targets. The compound, pelargonidin-3-O-glucoside was found to be most effective in computer aided models.

CONCLUSIONS

In conclusion, the TPL extract of T. pallida possesses significant anticancer activity. The tumor suppressive mechanism is due to apoptosis induced by activation of antioxidant enzymes and caspases and mediated by a change in the balance of pro- and anti-apoptotic genes that promotes cell death.

Not all cells are created equal - endosomal escape in fluorescent nanodiamonds in different cells

Successful delivery of fluorescent nanodiamonds (FNDs) into the cytoplasm is essential to many biological applications. Other applications require FNDs to stay within the endosomes. The diversity of cellular uptake of FNDs and following endosomal escape are less explored. In this article, we quantify particle uptake at a single cell level. We report that FNDs enter into the cells gradually. The number of internalized FNDs per cell differs significantly for the cell lines we investigated at the same incubation time. In HeLa cells we do not see any significant endosomal escape. We also found a wide distribution of FND endosomal escape efficiency within the same cell type. However, compared with HeLa cells, FNDs in HUVECs can easily escape from the endosomes and less than 25% FNDs remained in the vesicles after 4 h incubation time. We believe this work can bring more attention to the diversity of the cells and provide potential guidelines for future studies.

Quantum monitoring of cellular metabolic activities in single mitochondria

Free radicals play a vital role in all kinds of biological processes including immune responses. However, free radicals have short lifetimes and are highly reactive, making them difficult to measure using current methods. Here, we demonstrate that relaxometry measurement, or T1, inherited from the field of diamond magnetometry can be used to detect free radicals in living cells with subcellular resolution. This quantum sensing technique is based on defects in diamond, which convert a magnetic signal into an optical signal, allowing nanoscale magnetic resonance measurements. We functionalized fluorescent nanodiamonds (FNDs) to target single mitochondria within macrophage cells to detect the metabolic activity. In addition, we performed measurements on single isolated mitochondria. We were able to detect free radicals generated by individual mitochondria in either living cells or isolated mitochondria after stimulation or inhibition.

Evaluation of nephroprotective and cytotoxic effect of ethanolic extract of Mikania scandens leaves by using alloxan-induced diabetic nephropathy mice

Background

Diabetic is one of the fundamental persuasive of diabetic nephropathy and significantly sparks off kidney diseases and end stage renal failure globally.

Method

The current research was carried out to evaluate hypoglycemic potential and nephroprotective effect of ethanolic extract of Mikania scandens leaves by using alloxan-induced diabetic nephropathy (DN) mice. The mice were intraperitoneally treated with (200 mg/kg) Mikania scandens leaves extract and standard (120 mg/kg) metformin HCL solution up to 22 days. During this treatment period, we collected blood for evaluation of different types of parameters such as blood glucose level body weight at 0, 15, 22th days, serum creatinine, uric acid, total protein were estimated at the end of the experiment (day 22).

Result

Mikania scandens leaves extract significantly (p < 0.05) lessen blood glucose level, serum creatinine, total protein and uric acid. Apart this, cytotoxicity studies were assessed by Brine Shrimp Lethality Bioassay. By this method, we measure the dose of LC50. The plant has high LC50 dose thus cytotoxicity has ensued at massive amount and safe to administer.

Conclusion

Lowering of serum creatinine, uric acid and total protein recommend that the ethanolic extract of Mikania scandens possess potent nephroprotective activity and assure the traditional avail of this plant in the management of diabetes nephropathy.

Micro Versus Macro - The Effect of Environmental Confinement on Cellular Nanoparticle Uptake

While the microenvironment is known to alter the cellular behavior in terms of metabolism, growth and the degree of endoplasmic reticulum stress, its influence on the nanoparticle uptake is not yet investigated. Specifically, it is not clear if the cells cultured in a microenvironment ingest different amounts of nanoparticles than cells cultured in a macroenvironment (for example a petri dish). To answer this question, here we used J774 murine macrophages and fluorescent nanodiamonds (FND) as a model system to systematically compare the uptake efficiency of cells cultured in a petri dish and in a microfluidic channel. Specifically, equal numbers of cells were cultured in two devices followed by the FND incubation. Then cells were fixed, stained and imaged to quantify the FND uptake. We show that the FND uptake in the cells cultured in petri dishes is significantly higher than the uptake in a microfluidic chip where the alteration in CO2 environment, the cell culture medium pH and the surface area to volume ratio seem to be the underlying causes leading to this observed difference.

Co-circulation of dengue virus type 3-genotype I and type 2-Cosmopolitan genotype in 2018 outbreak in Dhaka, Bangladesh

Dengue virus (DENV) that caused an outbreak in Dhaka, Bangladesh during 2018 was analysed phylogenetically. DENV samples were classified into type 2-Cosmopolitan genotype (54%) and type 3-genotype I (46%), indicating co-circulation of two DENV types and resurgence of type 3 associated with genotype replacement.

Dengue infection in Dhaka City, Bangladesh

Dengue fever (DF) and dengue haemorrhagic fever (DHF) are now endemic in Bangladesh with outbreaks being reported quite frequently. This cross sectional study was done clinically suspected dengue patients were selected from different hospitals of Dhaka city, Bangladesh, from January 2008 to December 2008. The clinical features, risk factors and laboratory findings associated with dengue infection were investigated among 201 clinically suspected patients. Antibodies were detected in 137(68.2%) cases. Of these, 80(58.4%) were primary and 57(41.6%) as secondary dengue cases according to presence of dengue-specific IgM and/or IgG antibodies. Among primary cases, 70(87.5%) were DF and 10(12.5%) were DHF cases, in contrast to secondary cases, where 10(18.1%) were DF and 47(81.9%) were DHF cases. Majority (57.9%) of patients presented with Grade I and 42.1% had Grade II disease. Patients between 16-30 years were the most vulnerable age group (81.3% DF and 71.9% DHF patients). Males out-numbered females with 72.5% male vs. 27.5% female patients having DF and 68.4% male vs. 31.6% female patients having DHF. The monsoon period was the peak season for dengue infection. Headache and arthralgia were the most frequent symptoms in both DF and DHF, but vomiting was more common in DHF. The Tourniquet test was significantly positive among DHF than DF cases (p = 0.001). Platelet count was the only laboratory parameter that showed significantly higher values among DHF than DF cases (p = 0.001).