Measuring Cell Death by Propidium Iodide Uptake and Flow Cytometry

Bacterial species-specific modulatory effects on phenotype and function of camel blood leukocytes

Background

Recent studies have reported pathogen-species-specific modulating effects on the innate immune system. Escherichia coli, Staphylococcus aureus, and Streptococcus agalactiae are important pathogenic bacteria responsible for different infectious diseases in several animal species. In the present study, a whole blood culture with S. aureus, E. coli, or S. agalactiae and flow cytometry were used to investigate, whether stimulation with different bacterial species induces different immunomodulation patterns in camel leukocytes. The expression of different cell surface myeloid markers and cell adhesion molecules on monocytes and neutrophils was investigated. In addition, the capacity of monocytes and neutrophils to produce reactive oxygen species (ROS) was analyzed.

Results

Stimulation with either of the bacterial species resulted in the expansion of the camel CD14^highMHCII^high monocyte subset with a reduced fraction of CD14^highMHCII^low monocytes. For the CD14^lowMHCII^high monocytes, however, only stimulation with S. aureus or S. agalactiae increased their fractions in blood. Although all bacterial species elicited the upregulation of cell surface MHC class II molecules on granulocytes, the increase was, however, highest on cells stimulated with S. aureus. The expression levels of the two adhesion molecules, CD11a and CD18, on neutrophils and monocytes were differently affected by bacterial stimulation. Functionally, E. coli failed to stimulate ROS production in monocytes, while induced a strong ROS production response in granulocytes. S. agalactiae elicited a week ROS production in granulocytes when compared to the other two pathogens.

Conclusions

The different responsiveness of monocytes and granulocytes toward different bacterial species indicates different host-pathogen interaction mechanisms for the two cell populations. In addition, the phenotypic and functional differences between cells stimulated with E. coli, S. aureus, or S. agalactiae suggests pathogen-species-specific modulating effects of the bacterial pathogens on the camel innate myeloid cells.

Identification of novel genes involved in apoptosis of HIV-infected macrophages using unbiased genome-wide screening

Background

Macrophages, besides resting latently infected CD4+ T cells, constitute the predominant stable, major non-T cell HIV reservoirs. Therefore, it is essential to eliminate both latently infected CD4+ T cells and tissue macrophages to completely eradicate HIV in patients. Until now, most of the research focus is directed towards eliminating latently infected CD4+ T cells. However, few approaches have been directed at killing of HIV-infected macrophages either in vitro or in vivo. HIV infection dysregulates the expression of many host genes essential for the survival of infected cells. We postulated that exploiting this alteration may yield novel targets for the selective killing of infected macrophages.

Methods

We applied a pooled shRNA-based genome-wide approach by employing a lentivirus-based library of shRNAs to screen novel gene targets whose inhibition should selectively induce apoptosis in HIV-infected macrophages. Primary human MDMs were infected with HIV-eGFP and HIV-HSA viruses. Infected MDMs were transfected with siRNAs specific for the promising genes followed by analysis of apoptosis by flow cytometry using labelled Annexin-V in HIV-infected, HIV-exposed but uninfected bystander MDMs and uninfected MDMs. The results were analyzed using student’s t-test from at least four independent experiments.

Results

We validated 28 top hits in two independent HIV infection models. This culminated in the identification of four target genes, Cox7a2, Znf484, Cstf2t, and Cdk2, whose loss-of-function induced apoptosis preferentially in HIV-infected macrophages. Silencing these single genes killed significantly higher number of HIV-HSA-infected MDMs compared to the HIV-HSA-exposed, uninfected bystander macrophages, indicating the specificity in the killing of HIV-infected macrophages. The mechanism governing Cox7a2-mediated apoptosis of HIV-infected macrophages revealed that targeting respiratory chain complex II and IV genes also selectively induced apoptosis of HIV-infected macrophages possibly through enhanced ROS production.

Conclusions

We have identified above-mentioned novel genes and specifically the respiratory chain complex II and IV genes whose silencing may cause selective elimination of HIV-infected macrophages and eventually the HIV-macrophage reservoirs. The results highlight the potential of the identified genes as targets for eliminating HIV-infected macrophages in physiological environment as part of an HIV cure strategy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06346-7.

Immunomodulatory Effects of the Cyclooxygenase Inhibitor Lornoxicam on Phenotype and Function of Camel Blood Leukocytes

Simple Summary

The present study investigated the immunomodulatory effects of the unspecific cyclooxygenase inhibitor lornoxicam on the immunophenotype and some functions of dromedary camel blood leukocytes. Intravenous injection of camels with a single dose of lornoxicam induced a significant change in the camel leukogram, which is characterized by reduced cell numbers of all leukocyte subpopulations. In vitro analysis of cell vitality revealed a pro-apoptotic effect of lornoxicam on camel leukocytes, which may be responsible for the lornoxicam-induced leukocytopenia in vivo. Functional ex vivo and in vitro analysis of the key antimicrobial functions, phagocytosis and ROS production indicates inhibitory effects of lornoxicam on the antimicrobial capacity of the blood phagocytes, monocytes and neutrophils. Furthermore, lornoxicam induced an anti-inflammatory phenotype of monocytes, characterized by reduced expression of major histocompatibility complex (MHC) class II molecules and increased expression of CD163 molecules. The present study identified for the first time inhibitory effects of the COX-inhibitor lornoxicam on some phenotypic and functional properties of camel blood immune cells and recommends considering these effects when using lornoxicam in camel medicine.

Abstract

(1) Background: Lornoxicam is a nonsteroidal anti-inflammatory drug (NSAID) with analgesic, antiphlogistic and antipyretic effects. The improved tolerance of lornoxicam due to the relatively shorter elimination half-life in comparison to other members of the oxicams may favor its application in the management of pain and inflammation in race dromedary camels. There are no studies conducted yet on the immunomodulatory or immunotoxilogic effect of lornoxicam in camels. Therefore, the current study aimed to evaluate the immunomodulatory effects of the cyclooxygenase inhibitor lornoxicam on some phenotypic and functional properties of camel blood leukocytes; (2) Methods: Using flow cytometry, blood leukocyte composition, monocyte phenotype, and antimicrobial functions of neutrophils and monocytes were analyzed ex vivo after a single dose injection with lornoxicam. In addition, the effect of in vitro incubation of camel blood with lornoxicam on leukocyte cell vitality and antimicrobial functions were evaluated; (3) Results: The injection of camels with a single dose of lornoxicam resulted in a significant change in their leukogram with reduced numbers of total leukocytes, neutrophils, eosinophils, monocytes, and lymphocytes. Within the lymphocyte population, the numbers of CD4⁺ T cells, γδ T cells, and B cells decreased significantly in blood after injection of camels with lornoxicam. In addition, injection of lornoxicam resulted in decreased abundance of major histocompatibility complex (MHC) class II molecules and increased abundance of the scavenger receptor CD163 on blood monocytes, indicating an anti-inflammatory phenotype of monocytes. Functionally, administration of lornoxicam decreased the capacity of camel neutrophils and monocytes to uptake bacteria and to produce reactive oxygen species (ROS) after bacterial stimulation. Similarly, the in vitro whole blood incubation with lornoxicam resulted in reduced phagocytosis and ROS production activity of the camel blood phagocytes. Flow cytometric analysis of cell vitality, including cell necrosis and apoptosis, revealed a pro-apoptotic effect of lornoxicam on camel leukocytes; (4) Conclusions: Lornoxicam administration, at the dose and intervals utilized herein, induces significant changes in the phenotype and function of camel blood leukocytes. The reduced cell numbers of all studied leukocyte subpopulations in lornoxicam-treated camels, which seems to be a result of enhanced cell apoptosis, indicates an inhibitory effect rather than a modulatory effect of lornoxicam on the camel immune system, which need to be considered when using lornoxicam in camel medicine.

The ester derivatives obtained by C-ring modification of podophyllotoxin induce apoptosis and inhibited proliferation in PC-3M cells via down-regulation of PI3K/Akt signaling pathway

Podophyllotoxin (PPT) has been reported to have many pharmacological activities, especially its anti-tumor effects. To improve the cytotoxicity and selective effect of PPT, in this study, we have designed and synthesized 20 ester derivatives by introducing Boc-amino acids or organic acids at the C-4 position of PPT. The cytotoxicity of these compounds was evaluated with PC-3M, HemECs, A549, MCF-7 and HepG2 cells. We observed that the proliferation of PC-3M cells was inhibited by all 20 ester derivatives in the largest degree, comparing to the other cell lines. Comparing to PPT (IC₅₀ = 234.90 ± 20.7 nM), eight derivatives had better performance in inhabiting proliferation of PC-3M cells, six of them belong to Boc-amino acid ester derivatives, and the derivative named V-05 (IC₅₀ = 1.28 ± 0.1 nM) had the strongest inhibitation effect. Changes in cell proliferation and apoptotic signaling pathways were studied by DAPI staining, colony formation assay, migration assay, flow cytometry and western blot analysis. We found that V-05 were able to inhibit PC-3M cells proliferation and migration, and induced apoptosis by downregualting p-PI3K, p-Akt and Bcl-2, and upregulating Cleaved caspase-3 and Bax. Our research provides the first insight for the application of PPT derivatives in PC-3M cells, which may offer information to the effective medicine development for human prostate cancer treatment.

A traditional medicine, respiratory detox shot (RDS), inhibits the infection of SARS-CoV, SARS-CoV-2, and the influenza A virus in vitro

BACKGROUND

The ongoing global pandemic of coronavirus disease 2019 (COVID-19) has resulted in the infection of over 128 million people and has caused over 2.8 million deaths as of April 2021 in more than 220 countries and territories. Currently, there is no effective treatment for COVID-19 to reduce mortality. We investigated the potential anti-coronavirus activities from an oral liquid of traditional medicine, Respiratory Detox Shot (RDS), which contains mostly herbal ingredients traditionally used to manage lung diseases.

RESULTS

Here we report that RDS inhibited the infection of target cells by lenti-SARS-CoV, lenti-SARS-CoV-2, and hybrid alphavirus-SARS-CoV-2 (Ha-CoV-2) pseudoviruses, and by infectious SARS-CoV-2 and derived Ha-CoV-2 variants including B.1.1.7, B.1.351, P.1, B.1.429, B.1.2, B.1.494, B.1.1.207, B.1.258, and B.1.1.298. We further demonstrated that RDS directly inactivates the infectivity of SARS-CoV-2 virus particles. In addition, we found that RDS can also block the infection of target cells by Influenza A virus.

CONCLUSIONS

These results suggest that RDS may broadly inhibit the infection of respiratory viruses.

Pre-Senescence Induction in Hepatoma Cells Favors Hepatitis C Virus Replication and Can Be Used in Exploring Antiviral Potential of Histone Deacetylase Inhibitors

Recent evidence suggests that fibrotic liver injury in patients with chronic hepatitis C correlates with cellular senescence in damaged liver tissue. However, it is still unclear how senescence can affect replication of the hepatitis C virus (HCV). In this work, we report that an inhibitor of cyclin-dependent kinases 4/6, palbociclib, not only induced in hepatoma cells a pre-senescent cellular phenotype, including G1 arrest in the cell cycle, but also accelerated viral replicon multiplication. Importantly, suppression of HCV replication by direct acting antivirals (DAAs) was barely affected by pre-senescence induction, and vice versa, the antiviral activities of host-targeting agents (HTAs), such as inhibitors of human histone deacetylases (HDACi), produced a wide range of reactions-from a dramatic reduction to a noticeable increase. It is very likely that under conditions of the G1 arrest in the cell cycle, HDACi exhibit their actual antiviral potency, since their inherent anticancer activity that complicates the interpretation of test results is minimized.

Changes in Cell Vitality, Phenotype, and Function of Dromedary Camel Leukocytes After Whole Blood Exposure to Heat Stress in vitro

The dromedary camel (Camelus dromedarius) is well-adapted to the desert environment with the ability to tolerate increased internal body temperatures rising daily to 41–42°C during extreme hot. This study was undertaken to assess whether in vitro incubation of camel blood at 41°C, simulating conditions of heat stress, differently alters cell vitality, phenotype, and function of leukocytes, compared to incubation at 37°C (normothermia). Using flow cytometry, the cell vitality (necrosis and apoptosis), the expression of several cell markers and adhesion molecules, and the antimicrobial functions of camel leukocytes were analyzed in vitro. The fraction of apoptotic cells within the granulocytes, lymphocytes, and monocytes increased significantly after incubation of camel whole blood at 41°C for 4 h. The higher increase in apoptotic granulocytes and monocytes compared to lymphocytes suggests higher resistance of camel lymphocytes to heat stress. Functionally, incubation of camel blood at 41°C for 4 h enhanced the phagocytosis and ROS production activities of camel neutrophils and monocytes toward S. aureus. Monocytes from camel blood incubated at 41°C for 4 h significantly decreased their expression level of MHC class II molecules with no change in the abundance of CD163, resulting in a CD163^high MHC-II^low M2-like macrophage phenotype. In addition, heat stress treatment showed an inhibitory effect on the LPS-induced changes in camel monocytes phenotype. Furthermore, in vitro incubation of camel blood at 41°C reduced the expression of the cell adhesion molecules CD18 and CD11a on neutrophils and monocytes. Collectively, the present study identified some heat-stress-induced phenotypic and functional alterations in camel blood leukocytes, providing a paradigm for comparative immunology in the large animals. The clinical relevance of the observed changes in camel leukocytes for the adaptation of the camel immune response to heat stress conditions needs further in vitro and in vivo studies.

Antimicrobial activity of fermented Maillard reaction products, novel milk-derived material, made by whey protein and Lactobacillus rhamnosus and Lactobacillus gasseri on Clostridium perfringens

OBJECTIVE

The objective of this study was to evaluate the antimicrobial effects of fermented Maillard reaction products made by milk proteins (FMRPs) on Clostridium perfringens (C. perfringens), and to elucidate antimicrobial modes of FMRPs on the bacteria, using physiological and morphological analyses.

METHODS

Antimicrobial effects of FMRPs (whey protein plus galactose fermented by Lactobacillus rhamnosus [L. rhamnosus] 4B15 [Gal-4B15] or Lactobacillus gasseri 4M13 [Gal-4M13], and whey protein plus glucose fermented by L. rhamnosus 4B15 [Glc-4B15] or L. gasseri 4M13 [Glc-4M13]) on C. perfringens were tested by examining growth responses of the pathogen. Iron chelation activity analysis, propidium iodide uptake assay, and morphological analysis with field emission scanning electron microscope (FE-SEM) were conducted to elucidate the modes of antimicrobial activities of FMRPs.

RESULTS

When C. perfringens were exposed to the FMRPs, C. perfringens cell counts were decreased (p<0.05) by the all tested FMRPs; iron chelation activities by FMRPs, except for Glc-4M13. Propidium iodide uptake assay indicate that bacterial cellular damage increased in all FMRPs-treated C. perfringens, and it was observed by FE-SEM.

CONCLUSION

These results indicate that the FMRPs can destroy C. perfringens by iron chelation and cell membrane damage. Thus, it could be used in dairy products, and controlling intestinal C. perfringens.

Cannabidiol induces autophagy via ERK1/2 activation in neural cells

Autophagy is a lysosomal catabolic process essential to cell homeostasis and is related to the neuroprotection of the central nervous system. Cannabidiol (CBD) is a non-psychotropic phytocannabinoid present in Cannabis sativa. Many therapeutic actions have been linked to this compound, including autophagy activation. However, the precise underlying molecular mechanisms remain unclear, and the downstream functional significance of these actions has yet to be determined. Here, we investigated CBD-evoked effects on autophagy in human neuroblastoma SH-SY5Y and murine astrocyte cell lines. We found that CBD-induced autophagy was substantially reduced in the presence of CB1, CB2 and TRPV1 receptor antagonists, AM 251, AM 630 and capsazepine, respectively. This result strongly indicates that the activation of these receptors mediates the autophagic flux. Additionally, we demonstrated that CBD activates autophagy through ERK1/2 activation and AKT suppression. Interestingly, CBD-mediated autophagy activation is dependent on the autophagy initiator ULK1, but mTORC1 independent. Thus, it is plausible that a non-canonical pathway is involved. Our findings collectively provide evidence that CBD stimulates autophagy signal transduction via crosstalk between the ERK1/2 and AKT kinases, which represent putative regulators of cell proliferation and survival. Furthermore, our study sheds light on potential therapeutic cannabinoid targets that could be developed for treating neurodegenerative disorders.

Cell detachment ratio on pH-responsive chitosan: A useful biometric for prognostic judgment and drug efficacy assessment in oncology

The inherently unpredictable complexity of tumors impedes the widespread practice of the molecular biomarkers in outcome prediction. Alternatively, from the biophysical perspective, this study sought to investigate the applicability of the cell detachment ratio (CDR) derived from pH-responsive chitosan as a biometrical identifier for the disease state in cancer prognostic judgment and drug efficacy assessment. In the targeted therapy model, the repression of tumor dissemination in cells harboring aberrant ErbB signals (human non-small cell lung cancer cell line PC9 and breast cancer cell line BT474) were first demonstrated both in vitro and in vivo. Consequently, the corresponding CDR profile goes synchronously with the extent of cancer regression in response to the medication. Definitive integrins that drive the cell detachment were also verified through CDR examination following the integrin functional blockade. Conclusively, CDR is a promising clinical index for evaluation of the metastatic cell behaviors in terms of the cell detachment.

The antimicrobial efficacy of remote cold atmospheric plasma effluent against single and mixed bacterial biofilms of varying age

Cold atmospheric plasma (CAP) is a minimal food processing technology of increasing interest in the food industry, as it is mild in nature compared to traditional methods (e.g. pasteurisation) and thus can maintain the food's desirable qualities. However, due to this mild nature, the potential exists for post-treatment microbial survival and/or stress adaptation. Furthermore, biofilm inactivation by CAP is underexplored and mostly studied on specific foods or on plastic/polymer surfaces. Co-culture effects, biofilm age, and innate biofilm-associated resistance could all impact CAP efficacy, while studies on real foods are limited to the food product investigated without accounting for structural complexity. The effect of a Remote and Enclosed CAP device (Fourth State Medicine Ltd) was investigated on Escherichia coli and Listeria innocua grown as planktonic cells and as single or mixed bacterial biofilms of variable age, on a biphasic viscoelastic food model of controlled rheological and structural complexity. Post-CAP viability was assessed by plate counts, cell sublethal injury was quantified using flow cytometry, and biofilms were characterised and assessed using total protein content and microscopy techniques. A greater impact of CAP on planktonic cells was observed at higher air flow rates, where the ReCAP device operates in a mode more favourable to reactive oxygen species than reactive nitrogen species. Although planktonic E. coli was more susceptible to CAP than planktonic L. innocua, the opposite was observed in biofilm form. The efficacy of CAP was reduced with increasing biofilm age. Furthermore, E. coli produced much higher protein content in both single and mixed biofilms than L. innocua. Consequently, greater survival of L. innocua in mixed biofilms was attributed to a protective effect from E. coli. These results show that biofilm susceptibility to CAP is age and bacteria dependent, and that in mixed biofilms bacteria may become less susceptible to CAP. These findings are of significance to the food industry for the development of effective food decontamination methods using CAP.

Quantifying cell death induced by doxorubicin, hyperthermia or HIFU ablation with flow cytometry

Triggered release and targeted drug delivery of potent anti-cancer agents using hyperthermia-mediated focused-ultrasound (FUS) is gaining momentum in the clinical setting. In early phase studies, tissue biopsy samples may be harvested to assess drug delivery efficacy and demonstrate lack of instantaneous cell death due to FUS exposure. We present an optimised tissue cell recovery method and a cell viability assay, compatible with intra-cellular doxorubicin. Flow cytometry was used to determine levels of cell death with suspensions comprised of: (i) HT29 cell line exposed to hyperthermia (30 min at 47 °C) and/or doxorubicin, or ex-vivo bovine liver tissue exposed to (ii) hyperthermia (up to 2 h at 45 °C), or (iii) ablative high intensity FUS (HIFU). Flow cytometric analysis revealed maximal cell death in HT29 receiving both heat and doxorubicin insults and increases in both cell granularity (p < 0.01) and cell death (p < 0.01) in cells recovered from ex-vivo liver tissue exposed to hyperthermia and high pressures of HIFU (8.2 MPa peak-to-peak free-field at 1 MHz) relative to controls. Ex-vivo results were validated with microscopy using pan-cytokeratin stain. This rapid, sensitive and highly quantitative cell-viability method is applicable to the small masses of liver tissue typically recovered from a standard core biopsy (5-20 mg) and may be applied to tissues of other histological origins including immunostaining.

A Miniaturized Platform for Multiplexed Drug Response Imaging in Live Tumors

Simple Summary

We have developed an implantable microdevice that is placed into a live tumor, and can directly image how effective various chemotherapy drugs are at inducing cell death, without having to remove or process the tumor tissue. Currently drug optimization is performed by assessing tumor shrinkage after treating a patient with systemic doses of a chemotherapy agent; this only evaluates a single treatment at a time and typically takes weeks-months before an optimal treatment strategy is found (if found at all) for a specific patient. In contrast, using the technology presented here, a personalized cancer treatment strategy can potentially be optimized and tailored to a specific patient’s tumor characteristics within several hours, without requiring surgical tissue removal or prolonged trials of potentially ineffective chemotherapies.

Abstract

By observing the activity of anti-cancer agents directly in tumors, there is potential to greatly expand our understanding of drug response and develop more personalized cancer treatments. Implantable microdevices (IMD) have been recently developed to deliver microdoses of chemotherapeutic agents locally into confined regions of live tumors; the tissue can be subsequently removed and analyzed to evaluate drug response. This method has the potential to rapidly screen multiple drugs, but requires surgical tissue removal and only evaluates drug response at a single timepoint when the tissue is excised. Here, we describe a “lab-in-a-tumor” implantable microdevice (LIT-IMD) platform to image cell-death drug response within a live tumor, without requiring surgical resection or tissue processing. The LIT-IMD is inserted into a live tumor and delivers multiple drug microdoses into spatially discrete locations. In parallel, it locally delivers microdose levels of a fluorescent cell-death assay, which diffuses into drug-exposed tissues and accumulates at sites of cell death. An integrated miniaturized fluorescence imaging probe images each region to evaluate drug-induced cell death. We demonstrate ability to evaluate multi-drug response over 8 h using murine tumor models and show correlation with gold-standard conventional fluorescence microscopy and histopathology. This is the first demonstration of a fully integrated platform for evaluating multiple chemotherapy responses in situ. This approach could enable a more complete understanding of drug activity in live tumors, and could expand the utility of drug-response measurements to a wide range of settings where surgery is not feasible.

Artemisia annua L. Polyphenol-Induced Cell Death Is ROS-Independently Enhanced by Inhibition of JNK in HCT116 Colorectal Cancer Cells

c-Jun N-terminal kinase (JNK) is activated by chemotherapeutic reagents including natural plant polyphenols, and cell fate is determined by activated phospho-JNK as survival or death depending on stimuli and cell types. The purpose of this study was to elucidate the role of JNK on the anticancer effects of the Korean plant Artemisia annua L. (pKAL) polyphenols in p53 wild-type HCT116 human colorectal cancer cells. Cell morphology, protein expression levels, apoptosis/necrosis, reactive oxygen species (ROS), acidic vesicles, and granularity/DNA content were analyzed by phase-contrast microscopy; Western blot; and flow cytometry of annexin V/propidium iodide (PI)-, dichlorofluorescein (DCF)-, acridine orange (AO)-, and side scatter pulse height (SSC-H)/DNA content (PI)-stained cells. The results showed that pKAL induced morphological changes and necrosis or late apoptosis, which were associated with loss of plasma membrane/Golgi integrity, increased acidic vesicles and intracellular granularity, and decreased DNA content through downregulation of protein kinase B (Akt)/β-catenin/cyclophilin A/Golgi matrix protein 130 (GM130) and upregulation of phosphorylation of H2AX at Ser-139 (γ-H2AX)/p53/p21/Bak cleavage/phospho-JNK/p62/microtubule-associated protein 1 light chain 3B (LC3B)-I. Moreover, JNK inhibition by SP600125 enhanced ROS-independently pKAL-induced cell death through downregulation of p62 and upregulation of p53/p21/Bak cleavage despite a reduced state of DNA damage marker γ-H2AX. These findings indicate that phospho-JNK activated by pKAL inhibits p53-dependent cell death signaling and enhances DNA damage signaling, but cell fate is determined by phospho-JNK as survival rather than death in p53 wild-type HCT116 cells.

New triorganotin(iv) compounds with aromatic carboxylate ligands: synthesis and evaluation of the pro-apoptotic mechanism

Three new organotin(iv) carboxylate compounds were synthesized and structurally characterized by elemental analysis and FT-IR and multinuclear NMR (1H, 13C, 119Sn) spectroscopy. Single X-ray crystallography reveals that compound C2 has a monoclinic crystal system with space group P21/c having distorted bipyramidal geometry defined by C3SnO2. The synthesized compounds were screened for drug-DNA interactions via UV-Vis spectroscopy and cyclic voltammetry showing good activity with high binding constants. Theoretical investigations also support the reactivity of the compounds as depicted from natural bond orbital (NBO) analysis using Gaussian 09. Synthesized compounds were initially evaluated on two cancer (HeLa and MCF-7) cell lines and cytotoxicity to normal cells was evaluated using a non-cancerous (BHK-21) cell line. All the compounds were found to be active, with IC50 values less than that of the standard drug i.e. cisplatin. The cytotoxic effect of the most potent compound C2 was confirmed by LDH cytotoxicity assay and fluorescence imaging after PI staining. Apoptotic features in compound C2 treated cancer cells were visualized after DAPI staining while regulation of apoptosis was observed by reactive oxygen species generation, binding of C2 with DNA, a change in mitochondrial membrane potential and expression of activated caspase-9 and caspase-3 in cancer cells. Results are indicative of activation of the intrinsic pathway of apoptosis in C2 treated cancer cells.

Liver Phosphoenolpyruvate Carboxykinase-1 Downregulation via siRNA-Functionalized Graphene Oxide Nanosheets Restores Glucose Homeostasis in a Type 2 Diabetes Mellitus In Vivo Model

Metabolic disorders have been increasing at an alarming rate, and one such example of metabolic disorder is type 2 diabetes mellitus (T2DM). Unregulated gluconeogenesis in T2DM results in increased hepatic glucose output that causes fasting and postprandial hyperglycaemia. Extensive proofs have shown that the downregulation of the key rate-limiting enzyme phosphoenolpyruvate carboxykinase-1 (PCK-1) of gluconeogenesis improved glucose homeostasis in vivo. In the present study, we have synthesized and characterized liver-specific stearic acid conjugated octaarginine (StA-R8) functionalized 4arm-2K-PEGamineylated graphene oxide nanosheets (GPR8) for the delivery of siRNA against PCK-1 in T2DM C57BL/6 mice. We found that a single intravenous administration of siRNA (3 mg/kg BW) conjugated to GPR8 (GPR8:PCK-1_{siRNA(3 mg/kg BW)} conjugate) in an optimized N/P ratio exploited as a therapeutic nanoformulation maintained glucose homeostasis for nearly 4 weeks in the T2DM mice. Efficient silencing of PCK-1 in T2DM liver tissue increased the phosphorylation of serine-256 of FOXO-1, thus showing a marked decrease in hepatic gluconeogenesis. Gluconeogenesis control and consequently glucose output from the liver furthermore partially enhanced liver and muscle insulin sensitivity results in the stimulation of the insulin/AKT-2 signaling pathway which indirectly restored glucose homeostasis in the treated T2DM group. Our therapeutic nanoformulation also improved glycogen storage in the liver and membrane translocation of GLUT4 in the muscle of the treated T2DM group. In conclusion, GPR8:PCK-1_{siRNA (3 mg/Kg BW)} restored glucose homeostasis by controlling the hepatic glucose production and improved peripheral insulin sensitivity as a consequence of reduced hyperglycemia. Thus, the current approach offered an alternative strategy for the therapeutics for T2DM.

p53 Enhances Artemisia annua L. Polyphenols-Induced Cell Death Through Upregulation of p53-Dependent Targets and Cleavage of PARP1 and Lamin A/C in HCT116 Colorectal Cancer Cells

Plant-derived natural polyphenols exhibit anticancer activity without showing any noticeable toxicities to normal cells. The aim of this study was to investigate the role of p53 on the anticancer effect of polyphenols isolated from Korean Artemisia annua L. (pKAL) in HCT116 human colorectal cancer cells. We confirmed that pKAL induced reactive oxygen species (ROS) production, propidium iodide (PI) uptake, nuclear structure change, and acidic vesicles in a p53-independent manner in p53-null HCT116 cells through fluorescence microscopy analysis of DCF/PI-, DAPI-, and AO-stained cells. The pKAL-induced anticancer effects were found to be significantly higher in p53-wild HCT116 cells than in p53-null by hematoxylin staining, CCK-8 assay, Western blot, and flow cytometric analysis of annexin V/PI-stained cells. In addition, expression of ectopic p53 in p53-null cells was upregulated by pKAL in both the nucleus and cytoplasm, increasing pKAL-induced cell death. Moreover, Western bot analysis revealed that pKAL-induced cell death was associated with upregulation of p53-dependent targets such as p21, Bax and DR5 and cleavage of PARP1 and lamin A/C in p53-wild HCT116 cells, but not in p53-null. Taken together, these results indicate that p53 plays an important role in enhancing the anticancer effects of pKAL by upregulating p53 downstream targets and inducing intracellular cell death processes.

Lufenuron induces reproductive toxicity and genotoxic effects in pregnant albino rats and their fetuses

Insecticides and other agrochemicals have become indispensable components of the agricultural system to ensure a notable increase in crop yield and food production. As a natural consequence, chemical residues result in significantly increased contamination of both terrestrial and aquatic ecosystems. The present study evaluated the teratogenic, genotoxic, and oxidative stress effects of residual-level lufenuron exposure on pregnant rats during the organogenesis gestational period of both mother and fetus. The tested dams were divided into three groups; control (untreated), low-dose group (orally administered with 0.4 mg/kg lufenuron) and high-dose group (orally administered with 0.8 mg/kg lufenuron). The dams of the two treatment groups showed teratogenic abnormalities represented by the asymmetrical distribution of fetuses in both uterine horns, accompanied by observed resorption sites and intensive bleeding in the uterine horns, whereas their fetuses suffered from growth retardation, morphologic malformations, and skeletal deformations. Histologic examination of the liver and kidney tissues obtained from mothers and fetuses after lufenuron exposure revealed multiple histopathologic changes. DNA fragmentation and cell cycle perturbation were also detected in the liver cells of lufenuron-treated pregnant dams and their fetuses through comet assay and flow cytometry, respectively. Moreover, lufenuron-induced oxidative stress in the liver of mothers and fetuses was confirmed by the increased malondialdehyde levels and decreased levels of enzymatic antioxidants (glutathione peroxidase and superoxide dismutase). Taken together, it can be concluded that lufenuron has a great potential in exerting teratogenic, genotoxic, and oxidative stresses on pregnant rats and their fetuses upon chronic exposure to residual levels during the organogenesis gestational period. The obtained results in the present study imply that women and their fetuses may have the same risk.

Succinyl chitosan gold nanocomposite: Preparation, characterization, in vitro and in vivo anticandidal activity

Herein, we have successfully synthesized a novel N-Succinyl chitosan/gold nanocomposite (N-SuC/Au NC) using N-SuC and gold(III) chloride, and investigated the biocompatibility and antifungal activity. The synthesized N-SuC/Au NC was characterized by UV-visible spectroscopy, X-ray diffraction, field emission scanning electron microscope, and inductively coupled plasma atomic emission spectroscopy. The N-SuC/Au NC exhibited a strong inhibition effect towards pathogenic Candida albicans. Morphological analysis revealed the destruction of C. albicans cell membrane due to N-SuC/Au NC treatment. The in vitro and in vivo toxicity of N-SuC/Au NC was analyzed with HEK293T mammalian cells and zebrafish larvae, respectively. The synthesized N-SuC/Au NC demonstrated no cytotoxicity towards HEK293T cells up to 1200 μg/mL concentration. The survival rate of the zebrafish larvae at 120 hpf, was found as 100% up to 1200 μg/mL of N-SuC/Au NC exposure. The in vivo studies further confirmed the inhibitory effects of N-SuC/Au NC on the formation of C. albicans hyphae in infected zebrafish muscle tissue.

The fungicide dodine primarily inhibits mitochondrial respiration in Ustilago maydis, but also affects plasma membrane integrity and endocytosis, which is not found in Zymoseptoria tritici

Early reports in the fungus Ustilago maydis suggest that the amphipathic fungicide dodine disrupts the fungal plasma membrane (PM), thereby killing this corn smut pathogen. However, a recent study in the wheat pathogen Zymoseptoria tritici does not support such mode of action (MoA). Instead, dodine inhibits mitochondrial ATP-synthesis, both in Z. tritici and U. maydis. This casts doubt on an fungicidal activity of dodine at the PM. Here, we use a cell biological approach and investigate further the effect of dodine on the plasma membrane in both fungi. We show that dodine indeed breaks the integrity of the PM in U. maydis, indicated by a concentration-dependent cell depolarization. In addition, the fungicide reduces PM fluidity and arrests endocytosis by inhibiting the internalization of endocytic vesicles at the PM. This is likely due to impaired recruitment of the actin-crosslinker fimbrin to endocytic actin patches. However, quantitative data reveal that the effect on mitochondria represents the primary MoA in U. maydis. None of these plasma membrane-associated effects were found in dodine-treated Z. tritici cells. Thus, the physiological effect of an anti-fungal chemistry can differ between pathogens. This merits consideration when characterizing a given fungicide.

Vibrio deploys type 2 secreted lipase to esterify cholesterol with host fatty acids and mediate cell egress

Pathogens find diverse niches for survival including inside a host cell where replication occurs in a relatively protective environment. Vibrio parahaemolyticus is a facultative intracellular pathogen that uses its type 3 secretion system 2 (T3SS2) to invade and replicate inside host cells. Analysis of the T3SS2 pathogenicity island encoding the T3SS2 appeared to lack a mechanism for egress of this bacterium from the invaded host cell. Using a combination of molecular tools, we found that VPA0226, a constitutively secreted lipase, is required for escape of V. parahaemolyticus from the host cells. This lipase must be delivered into the host cytoplasm where it preferentially uses fatty acids associated with innate immune response to esterify cholesterol, weakening the plasma membrane and allowing egress of the bacteria. This study reveals the resourcefulness of microbes and the interplay between virulence systems and host cell resources to evolve an ingenious scheme for survival and escape.

A Recent Overview of Microbes and Microbiome Preservation

Microbes are mediators in almost all ecosystem processes and act as a pivotal game changer in various ecological activities, globally. Therefore, understanding of microbial community structure and related functions in different environmental and micro-environmental niches is not only critical, but also a matter of greatest importance. Due to our inability to cultivate and preserve all sorts of microorganisms, we are losing some ecologically and industrially relevant components of microbial community, due to extinction caused by environmental and climatic variations with time. Intact sample and microbiome preservation are crucial for future cultivation as well as to study the effects of ecological and climatic variations on community functionality and shift with time, using OMICS. Although, methods for pure culture preservation are almost optimized, the techniques of microbiome preservation still remain as an unsolved challenge for microbiologists due to technical and physiological constraints. Present article discusses, recent approaches of microbial preservation with special reference to intact sample, mixed culture and microbiome preservation. It also incorporates recent practices used to achieve the highest viability and metabolic activities in long-term preserved microbiome.

Aquatic toxicity and mode of action of CdS and ZnS nanoparticles in four microalgae species

This study reports the differences in toxic action between cadmium sulfide (CdS) and zinc sulfide (ZnS) nanoparticles (NPs) prepared by recently developed xanthate-mediated method. The aquatic toxicity of the synthesized NPs on four marine microalgae species was explored. Growth rate, esterase activity, membrane potential, and morphological changes of microalgae cells were evaluated using flow cytometry and optical microscopy. CdS and ZnS NPs demonstrated similar level of general toxicity and growth-rate inhibition to all used microalgae species, except the red algae P. purpureum. More specifically, CdS NPs caused higher inhibition of growth rate for C. muelleri and P. purpureum, while ZnS NPs were more toxic for A. ussuriensis and H. akashiwo species. Our findings suggest that the sensitivity of different microalgae species to CdS and ZnS NPs depends on the chemical composition of NPs and their ability to interact with the components of microalgal cell-wall. The red microalga was highly resistant to ZnS NPs most likely due to the presence of phycoerythrin proteins in the outer membrane bound Zn²⁺ cations defending their cells from further toxic influence. The treatment with CdS NPs caused morphological changes and biochemical disorder in all tested microalgae species. The toxicity of CdS NPs is based on their higher photoactivity under visible light irradiation and lower dissociation in water, which allows them to generate more reactive oxygen species and create a higher risk of oxidative stress to aquatic organisms. The results of this study contribute to our understanding of the parameters affecting the aquatic toxicity of semiconductor NPs and provide a basis for further investigations.

Differential Th Cell-Related Immune Responses in Young Physically Active Men after an Endurance Effort

The participation of T cell subsets in the modulation of immunity in athletes triggered by maximal effort was investigated. In total, 80 physically active young men (range 16-20 years) were divided into 5 age groups: 16, 17, 18, 19, and 20 years old. They performed efficiency tests on mechanical treadmills until exhaustion. White blood cell (WBC) and lymphocyte (LYM) counts were determined, and the type 1 (Th1), type 2 (Th2) helper T cells, T helper 17 (Th17), and T regulatory (Treg) cell distribution and plasma levels of selected cytokines were analyzed. An increase in WBC and LYM counts after the test and in Th1 and Treg cells after the test and in recovery was observed. There were no changes in Th2 cells. An increase in interleukins (IL): IL-2 and IL-8 was observed. The IL-6 level was altered in all studied groups. IL-17A and interferon gamma (IFN-γ) levels were increased in all studied groups. The mechanism of differential T cell subset activation may be related to athletes' age. The novel findings of this study are the involvement of Th17 cells in post-effort immune responses and the participation of IL-6 in post-effort and the long-term biological effect of endurance effort.

Toxicity of Carbon, Silicon, and Metal-Based Nanoparticles to the Hemocytes of Three Marine Bivalves

Simple Summary

The growing nanotechnology industry disposes of a variety of nanoparticles with different physiochemical properties in everyday life. However, the dependence of the safety and toxicity of nanoparticles on their physicochemical properties remains unclear. Bivalve molluscs represent an efficient model for the investigation of nanoparticle toxicity owing to their filtrating ability and feeding on particles suspended in the water. Moreover, the blood cells of bivalve molluscs, the hemocytes, have been suggested as a good analog test-object to mammalian immune cells, phagocytes. In this study, we used hemocytes of three marine bivalve species, namely, Crenomytilus grayanus, Modiolus modiolus, and Arca boucardi, to evaluate and compare the toxic effects of 10 different types of nanoparticles. We gave short-term exposure of the nanoparticles to the hemocytes and registered viability and changes in their cell membrane polarization by employing flow cytometry. Metal-based nanoparticles were the most toxic to the cells of all three tested bivalve mollusc species. However, the sensitivity to different nanoparticle types varied between species. Moreover, the registered cell membrane depolarization indicated an early toxic response and raised concern that chronic long-term exposure of nanoparticles (even if they were previously declared as safe) is a serious threat for aquatic organisms.

Abstract

Nanoparticles (NPs) have broad applications in medicine, cosmetics, optics, catalysis, environmental purification, and other areas nowadays. With increasing annual production of NPs, the risks of their harmful influence on the environment and human health are also increasing. Currently, our knowledge about the mechanisms of the interaction between NPs and living organisms is limited. The marine species and their habitat environment are under continuous stress owing to the anthropogenic activities, which result in the release of NPs in the aquatic environment. We used a bioassay model with hemocytes of three bivalve mollusc species, namely, Crenomytilus grayanus, Modiolus modiolus, and Arca boucardi, to evaluate the toxicity of 10 different types of NPs. Specifically, we compared the cytotoxic effects and cell-membrane polarization changes in the hemocytes exposed to carbon nanotubes, carbon nanofibers, silicon nanotubes, cadmium and zinc sulfides, Au-NPs, and TiO₂ NPs. Viability and the changes in hemocyte membrane polarization were measured by the flow cytometry method. The highest aquatic toxicity was registered for metal-based NPs, which caused cytotoxicity to the hemocytes of all the studied bivalve species. Our results also highlighted different sensitivities of the used tested mollusc species to specific NPs.

Cancer cell discrimination and dynamic viability monitoring through wash-free bioimaging using AIEgens

Cancer cell discrimination and cellular viability monitoring are closely related to human health. A universal and convenient fluorescence system with a dual function of wide-spectrum cancer cell discrimination and dynamic cellular viability monitoring is desperately needed, and is still extremely challenging. Herein we present a series of aggregation-induced emission luminogens (AIEgens) (denoted as IVP) which can allow accurate discrimination between cancer and normal cells and dynamic monitoring of cellular viability through mitochondria-nucleolus migration. By regulating the lengths and positions of alkyl chains in IVP molecules, we systematically studied the discrimination behavior of these AIEgens between cancer cells and normal cells and further investigated how they can migrate between the mitochondria and nucleolus based on the change of mitochondrial membrane potential (ΔΨ m). Using IVP-02 as a model molecule, wash-free bioimaging, excellent two-photon properties, and low cytotoxicity were demonstrated. This present work proves that these designed IVP AIEgens show great potential for cancer identification and metastasis monitoring, as well as activity evaluation and screening of drugs.

Label-free platform on pH-responsive chitosan: Adhesive heterogeneity for cancer stem-like cell isolation from A549 cells via integrin β4

Great efforts have been paid to develop methodologies for cancer stem-like cell (CSLC) isolation in anti-cancer research. The major obstacle lies in the lack of generic biomarkers for different cancer types and the requirement of complicated immuno-labeling procedures. The purpose of this study is to establish a label-free platform for CSLC isolation using pH-responsive chitosan. Based on the adhesive heterogeneity, 15.7 ± 1.9 % of human non-small cell lung cancer (NSCLC) cell line A549 detached from the chitosan substrate following medium pH elevation from 6.99 to 7.65 within 1 h. As a result, this subpopulation of cells with low adhesiveness exhibited superior CSLC hallmarks, including self-renewal, invasive and metastatic potential, therapeutic-resistance, colony formation in vitro, as well as nude mice xenograft in vivo for tumorigenesis, in comparison with their high-adhesive counterpart. Furthermore, integrin β4 is decisive in controlling CSLC detachment of NSCLC. Conclusively, this pH-dependent isolation provides new insights into biomaterial-based CSLC isolation.

T helper cell-related changes in peripheral blood induced by progressive effort among soccer players

Objectives

The regulatory mechanisms affecting the modulation of the immune system accompanying the progressive effort to exhaustion, particularly associated with T cells, are not fully understood. We analysed the impact of two progressive effort protocols on T helper (Th) cell distribution and selected cytokines.

Methods

Sixty-two male soccer players with a median age of 17 (16–29) years performed different protocols for progressive exercise until exhaustion: YO-YO (YYRL1) and Beep. Blood samples for all analyses were taken three times: at baseline, post-effort, and in recovery.

Results

The percentage of Th1 cells increased post-effort and in recovery. The post-effort percentage of Th1 cells was higher in the Beep group compared to the YYRL1 group. Significant post-effort increase in Th17 cells was observed in both groups. The post-effort percentage of regulatory T cells (Treg) increased in the Beep group. An increased post-effort concentration of IL-2, IL-6, IL-8 and IFN-γ in both groups was observed. Post-effort TNF-α and IL-10 levels were higher than baseline in the YYRL1 group, while the post-effort IL-17A concentration was lower than baseline only in the Beep group. The recovery IL-2, IL-4, TNF-α and IFN-γ levels were higher than baseline in the YYRL1 group. The recovery IL-4, IL-6, IL-8, TNF-α and IFN-γ values were higher than baseline in the Beep group.

Conclusion

The molecular patterns related to cytokine secretion are not the same between different protocols for progressive effort. It seems that Treg cells are probably the key cells responsible for silencing the inflammation and enhancing anti-inflammatory pathways.

CRISPR-cas3 of Salmonella Upregulates Bacterial Biofilm Formation and Virulence to Host Cells by Targeting Quorum-Sensing Systems

Salmonella is recognized as one of the most common microbial pathogens worldwide. The bacterium contains the clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated (Cas) systems, providing adaptive immunity against invading foreign nucleic acids. Previous studies suggested that certain bacteria employ the Cas proteins of CRISPR-Cas systems to target their own genes, which also alters the virulence during invasion of mammals. However, whether CRISPR-Cas systems in Salmonella have similar functions during bacterial invasion of host cells remains unknown. Here, we systematically analyzed the genes that are regulated by Cas3 in a type I-E CRISPR-Cas system and the virulence changes due to the deletion of cas3 in Salmonella enterica serovar Enteritidis. Compared to the cas3 gene wild-type (cas3 WT) Salmonella strain, cas3 deletion upregulated the lsrFGBE genes in lsr (luxS regulated) operon related to quorum sensing (QS) and downregulated biofilm-forming-related genes and Salmonella pathogenicity island 1 (SPI-1) genes related to the type three secretion system (T3SS). Consistently, the biofilm formation ability was downregulated in the cas3 deletion mutant (Δcas3). The bacterial invasive and intracellular capacity of Δcas3 to host cells was also reduced, thereby increasing the survival of infected host cells and live chickens. By the transcriptome-wide screen (RNA-Seq), we found that the cas3 gene impacts a series of genes related to QS, the flagellum, and SPI-1-T3SS system, thereby altering the virulence phenotypes. As QS SPI-1-T3SS and CRISPR-Cas systems are widely distributed in the bacteria kingdom, our findings extend our understanding of virulence regulation and pathogenicity in mammalian hosts for Salmonella and potentially other bacteria.

Matrices (re)loaded: Durability, viability, and fermentative capacity of yeast encapsulated in beads of different composition during long-term fed-batch culture

Encapsulated microbes have been used for decades to produce commodities ranging from methyl ketone to beer. Encapsulated cells undergo limited replication, which enables them to more efficiently convert substrate to product than planktonic cells and which contributes to their stress resistance. To determine how encapsulated yeast supports long-term, repeated fed-batch ethanologenic fermentation, and whether different matrices influence that process, fermentation and indicators of matrix durability and cell viability were monitored in high-dextrose, fed-batch culture over 7 weeks. At most timepoints, ethanol yield (g/g) in encapsulated cultures exceeded that in planktonic cultures. And frequently, ethanol yield differed among the four matrices tested: sodium alginate crosslinked with Ca2+ and chitosan, sodium alginate crosslinked with Ca2+ , Protanal alginate crosslinked with Ca2+ and chitosan, Protanal alginate crosslinked with Ca2+ , with the last of these consistently demonstrating the highest values. Young's modulus and viscosity were higher for matrices crosslinked with chitosan over the first week; thereafter values for both parameters declined and were indistinguishable among treatments. Encapsulated cells exhibited greater heat shock tolerance at 50°C than planktonic cells in either stationary or exponential phase, with similar thermotolerance observed across all four matrix types. Altogether, these data demonstrate the feasibility of re-using encapsulated yeast to convert dextrose to ethanol over at least 7 weeks.

Fluorescence in situ hybridization (FISH) and cell sorting of living bacteria

Despite the development of several cultivation methods, the rate of discovery of microorganisms that are yet-to-be cultivated outpaces the rate of isolating and cultivating novel species in the laboratory. Furthermore, no current cultivation technique is capable of selectively isolating and cultivating specific bacterial taxa or phylogenetic groups independently of morphological or physiological properties. Here, we developed a new method to isolate living bacteria solely based on their 16S rRNA gene sequence. We showed that bacteria can survive a modified version of the standard fluorescence in situ hybridization (FISH) procedure, in which fixation is omitted and other factors, such as centrifugation and buffers, are optimized. We also demonstrated that labelled DNA probes can be introduced into living bacterial cells by means of chemical transformation and that specific hybridization occurs. This new method, which we call live-FISH, was then combined with fluorescence-activated cell sorting (FACS) to sort specific taxonomic groups of bacteria from a mock and natural bacterial communities and subsequently culture them. Live-FISH represents the first attempt to systematically optimize conditions known to affect cell viability during FISH and then to sort bacterial cells surviving the procedure. No sophisticated probe design is required, making live-FISH a straightforward method to be potentially used in combination with other single-cell techniques and for the isolation and cultivation of new microorganisms.

Increased Cell Detachment Ratio of Mesenchymal-Type Lung Cancer Cells on pH-Responsive Chitosan through the β3 Integrin

Chitosan is sensitive to environmental pH values due to its electric property. This study investigates whether the pH-responsive chitosan assay can provide a simple method to evaluate the aggressive behavior of cancer cells with cell detachment ratio. The epithelial–mesenchymal transition (EMT) is induced with transforming growth factor-β1 (TGF-β1) in the human non-small cell lung cancer cell line (A549). EMT-induced cells and untreated cells are cultured on chitosan substrates at pH 6.99 for 24 h, followed by pH 7.65 for 1 h. The cell detachment ratio (CDR) on pH-responsive chitosan rises with an increasing of the TGF-β1 concentration. The protein array reveals that the expression levels of the α2, α3, α5, β2, and β3 integrins are higher in EMT-induced A549 cells than in untreated cells. A further inhibition assay shows that adding β3 integrin blocking antibodies significantly decreases the CDR of EMT-induced cells from 32.7 ± 5.7% to 17.8 ± 2.1%. The CDR of mesenchymal-type lung cancer cells increases on pH-responsive chitosan through the β3 integrin. Notably, the CDR can be theoretically predicted according to the individual CDR on the pH-responsive chitosan surface, irrespective of heterogeneous cell mixture. The pH-responsive chitosan assay serves as a simple in vitro model to investigate the aggressive behavior of lung cancer including the heterogeneous cell population.

A Novel 3D Scaffold for Cell Growth to Asses Electroporation Efficacy

Tumor electroporation (EP) refers to the permeabilization of the cell membrane by means of short electric pulses thus allowing the potentiation of chemotherapeutic drugs. Standard plate adhesion 2D cell cultures can simulate the in vivo environment only partially due to lack of cell–cell interaction and extracellular matrix (ECM). In this study, we assessed a novel 3D scaffold for cell cultures based on hyaluronic acid and ionic-complementary self-assembling peptides (SAPs), by studying the growth patterns of two different breast carcinoma cell lines (HCC1569 and MDA-MB231). This 3D scaffold modulates cell shape and induces extracellular matrix deposit around cells. In the MDA-MB 231 cell line, it allows three-dimensional growth of structures known as spheroids, while in HCC1569 it achieves a cell organization similar to that observed in vivo. Interestingly, we were able to visualize the electroporation effect on the cells seeded in the new scaffold by means of standard propidium iodide assay and fluorescence microscopy. Thanks to the presence of cell–cell and cell–ECM interactions, the new 3D scaffold may represent a more reliable support for EP studies than 2D cancer cell cultures and may be used to test new EP-delivered drugs and novel EP protocols.

Antibacterial activities, proposed mode of action and cytotoxicity of leaf extracts from Triumfetta welwitschii against Pseudomonas aeruginosa

BACKGROUND

Pseudomonas aeruginosa has become a main cause of Gram-negative infection, particularly in patients with compromised immunity. High rates of resistance to antibiotics are associated with nosocomial infections caused by P. aeruginosa strains. The search for novel antimicrobials has been necessitated by the emergence of antimicrobial resistance in some bacteria Plant-based antimicrobials has great potential to combat microbial infections using a variety of mechanisms. Triumfetta welwitschii plant roots are traditionally used to treat symptoms of diarrhoea and fever, suggesting that it possess antimicrobial and immunomodulatory effects. Since research investigating antimicrobial properties of the roots of Triumfetta welwitschii has been explored, there is need to investigate the antimicrobial activity of its leaf extracts in order to probe their prospective use as new antimicrobial agents that can be used to combat nosocomial infections. The objective of this study was to evaluate the antibacterial activities, the mode of action and cytotoxicity of T. welwitschii leaf extracts.

METHOD

Extracts of T. welwitschii leaves were obtained using eight different solvents, the serial exhaustive extraction method and the cold maceration technique. In vitro antibacterial activity evaluation of the extracts was done on eight bacterial isolates using the broth microdilution method. The mode of action for the most potent extracts was investigated using the rhodamine 6G efflux assay and the propidium iodide-based membrane damage assay. Toxicity of the extracts was evaluated using the haemolytic and MTT (3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) assays.

RESULTS

The results showed that acetone, ethanol and dichlorometane: methanol extracts had the most potent antibacterial activities against Pseudomonas aeruginosa (ATCC 27853). All three extracts caused membrane disruption of P. aeruginosa as shown by nucleic acid leakage. All three extracts were unable to inhibit efflux pumps.

CONCLUSION

The presence of antibacterial activities and low toxicity shown by the extracts indicates that the plant may be a source of effective antibacterial against some bacterial infections caused by P. aeruginosa. The disruption of membrane integrity is one possible mode of action of antibacterial activity of the potent extracts.

Erythrosin B: a versatile colorimetric and fluorescent vital dye for bacteria

Rapidly assaying cell viability for diverse bacteria species is not always straightforward. In eukaryotes, cell viability is often determined using colorimetric dyes; however, such dyes have not been identified for bacteria. We screened different dyes and found that erythrosin B (EB), a visibly red dye with fluorescent properties, functions as a vital dye for many Gram-positive and -negative bacteria. EB worked at a similar concentration for all bacteria studied and incubations were as short as 5 min. Given EB's spectral properties, diverse experimental approaches are possible to rapidly visualize and/or quantitate dead bacterial cells in a population. As the first broadly applicable colorimetric viability dye for bacteria, EB provides a cost-effective alternative for researchers in academia and industry.

Genetically Encoded Photosensitizers as Light-Triggered Antimicrobial Agents

Diseases caused by multi-drug resistant pathogens have become a global concern. Therefore, new approaches suitable for treating these bacteria are urgently needed. In this study, we analyzed genetically encoded photosensitizers (PS) related to the green fluorescent protein (GFP) or light-oxygen-voltage (LOV) photoreceptors for their exogenous applicability as light-triggered antimicrobial agents. Depending on their specific photophysical properties and photochemistry, these PSs can produce different toxic ROS (reactive oxygen species) such as O₂^•− and H₂O₂ via type-I, as well as ¹O₂ via type-II reaction in response to light. By using cell viability assays and microfluidics, we could demonstrate differences in the intracellular and extracellular phototoxicity of the applied PS. While intracellular expression and exogenous supply of GFP-related PSs resulted in a slow inactivation of E. coli and pathogenic Gram-negative and Gram-positive bacteria, illumination of LOV-based PSs such as the singlet oxygen photosensitizing protein SOPP3 resulted in a fast and homogeneous killing of these microbes. Furthermore, our data indicate that the ROS type and yield as well as the localization of the applied PS protein can strongly influence the antibacterial spectrum and efficacy. These findings open up new opportunities for photodynamic inactivation of pathogenic bacteria.

First Results from a Screening of 300 Naturally Occurring Compounds: 4,6-dibromo-2-(2',4'-dibromophenoxy)phenol, 4,5,6-tribromo-2-(2',4'-dibromophenoxy)phenol, and 5-epi-nakijinone Q as Substances with the Potential for Anticancer Therapy

There is a variety of antineoplastic drugs that are based on natural compounds from ecological niches with high evolutionary pressure. We used two cell lines (Jurkat J16 and Ramos) in a screening to assess 300 different naturally occurring compounds with regard to their antineoplastic activity. The results of the compounds 4,6-dibromo-2-(2′,4′-dibromophenoxy)phenol (P01F03), 4,5,6-tribromo-2-(2′,4′-dibromophenoxy)phenol (P01F08), and 5-epi-nakijinone Q (P03F03) prompted us to perform further research. Using viability and apoptosis assays on the cell lines of primary human leukemic and normal hematopoietic cells, we found that P01F08 induced apoptosis in the cell lines at IC50 values between 1.61 and 2.95 μM after 72 h. IC50 values of peripheral blood mononuclear cells (PBMNCs) from healthy donors were higher, demonstrating that the cytotoxicity in the cell lines reached 50%, while normal PBMNCs were hardly affected. The colony-forming unit assay showed that the hematopoietic progenitor cells were not significantly affected in their growth by P01F08 at a concentration of 3 μM. P01F08 showed a 3.2-fold lower IC50 value in primary leukemic cells [acute myeloid leukemia (AML)] compared to the PBMNC of healthy donors. We could confirm the antineoplastic effect of 5-epi-nakijinone Q (P03F03) on the cell lines via the induction of apoptosis but noted a similarly strong cytotoxic effect on normal PBMNCs.

Synthesis, characterization, and anticancer activity of Schiff bases

Five Schiff bases, 2-((3-chlorophenylimino)methyl)-5-(diethylamino)phenol (L1), 2-((2,4-dichlorophenylimino)methyl)-5-(diethylamino)phenol (L2), 5-(diethylamino)-2-((3,5-dimethylphenylimino)methyl)phenol (L3), 2-((2-chloro-4-methylphenylimino)methyl)-5-(diethylamino)phenol (L4), and 5-(diethylamino)-2-((2,6-diethylphenylimino)methyl)phenol (L5) were synthesized and characterized by elemental analysis, FT-IR, ¹H and ¹³C NMR spectroscopy. Three of the compounds (L1, L2, and L4) were analyzed by single crystal X-ray diffraction: L1 and L2 crystallized in orthorhombic P2₁2₁2₁ and Pca2₁ space group, respectively, while L4 crystallized in monoclinic P2₁/c space group. Theoretical investigations were performed for all the synthesized compounds to evaluate the structural details. Drug-DNA interaction studies results from UV-Vis spectroscopy and electrochemistry complement that the compounds bind to DNA through electrostatic interactions. The cytotoxicity of the synthesized compounds was studied against cancer cell lines (HeLa and MCF-7) and a normal cell line (BHK-21) by means of an MTT assay compared to carboplatin, featuring IC₅₀ values in the micromolar range. The pro-apoptotic mechanism for the active compound L5 was evaluated by fluorescence microscopy, cell cycle analysis, caspase-9 and -3 activity, reactive oxygen species production, and DNA binding studies that further strengthen the results of that L5 is a potent drug against cancer.Communicated by Ramaswamy H. Sarma.

Homotrimerization Approach in the Design of Thrombospondin-1 Mimetic Peptides with Improved Potency in Triggering Regulated Cell Death of Cancer Cells

In order to optimize the potency of the first serum-stable peptide agonist of CD47 (PKHB1) in triggering regulated cell death of cancer cells, we designed a maturation process aimed to mimic the trimeric structure of the thrombospondin-1/CD47 binding epitope. For that purpose, an N-methylation scan of the PKHB1 sequence was realized to prevent peptide aggregation. Structural and pharmacological analyses were conducted in order to assess the conformational impact of these chemical modifications on the backbone structure and the biological activity. This structure-activity relationship study led to the discovery of a highly soluble N-methylated peptide that we termed PKT16. Afterward, this monomer was used for the design of a homotrimeric peptide mimic that we termed [PKT16]₃, which proved to be 10-fold more potent than its monomeric counterpart. A pharmacological evaluation of [PKT16]₃ in inducing cell death of adherent (A549) and nonadherent (MEC-1) cancer cell lines was also performed.

Stearoyl-CoA Desaturase 1 Protects Ovarian Cancer Cells from Ferroptotic Cell Death

Activation of ferroptosis, a recently described mechanism of regulated cell death, dramatically inhibits growth of ovarian cancer cells. Given the importance of lipid metabolism in ferroptosis and the key role of lipids in ovarian cancer, we examined the contribution to ferroptosis of stearoyl-CoA desaturase (SCD1, SCD), an enzyme that catalyzes the rate-limiting step in monounsaturated fatty acid synthesis in ovarian cancer cells. SCD1 was highly expressed in ovarian cancer tissue, cell lines, and a genetic model of ovarian cancer stem cells. Inhibition of SCD1 induced lipid oxidation and cell death. Conversely, overexpression of SCD or exogenous administration of its C16:1 and C18:1 products, palmitoleic acid or oleate, protected cells from death. Inhibition of SCD1 induced both ferroptosis and apoptosis. Inhibition of SCD1 decreased CoQ₁₀, an endogenous membrane antioxidant whose depletion has been linked to ferroptosis, while concomitantly decreasing unsaturated fatty acyl chains in membrane phospholipids and increasing long-chain saturated ceramides, changes previously linked to apoptosis. Simultaneous triggering of two death pathways suggests SCD1 inhibition may be an effective component of antitumor therapy, because overcoming this dual mechanism of cell death may present a significant barrier to the emergence of drug resistance. Supporting this concept, we observed that inhibition of SCD1 significantly potentiated the antitumor effect of ferroptosis inducers in both ovarian cancer cell lines and a mouse orthotopic xenograft model. Our results suggest that the use of combined treatment with SCD1 inhibitors and ferroptosis inducers may provide a new therapeutic strategy for patients with ovarian cancer. SIGNIFICANCE: The combination of SCD1 inhibitors and ferroptosis inducers may provide a new therapeutic strategy for the treatment of ovarian cancer patients.See related commentary by Carbone and Melino, p. 5149.

Tibolone attenuates inflammatory response by palmitic acid and preserves mitochondrial membrane potential in astrocytic cells through estrogen receptor beta

Palmitic acid (PA) induces several metabolic and molecular changes in astrocytes, and, it is involved in pathological conditions related to neurodegenerative diseases. Previously, we demonstrated that tibolone, a synthetic steroid with estrogenic, progestogenic and androgenic actions, protects cells from mitochondrial damage and morphological changes induced by PA. Here, we have evaluated which estrogen receptor is involved in protective actions of tibolone and analyzed whether tibolone reverses gene expression changes induced by PA. Tibolone actions on astrocytic cells were mimicked by agonists of estrogen receptor α (ERα) and β (ERβ), but the blockade of both ERs suggested a predominance of ERβ on mitochondria membrane potential. Expression analysis showed a significant effect of tibolone on genes associated with inflammation such as IL6, IL1B and miR155-3p. It is noteworthy that tibolone attenuated the increased expression of TERT, TERC and DNMT3B genes induced by palmitic acid. Our results suggest that tibolone has anti-inflammatory effects and can modulate pathways associated with DNA methylation and telomeric complex. However, future studies are needed to elucidate the role of epigenetic mechanisms and telomere-associated proteins on tibolone actions.

An optogenetic toolbox of LOV-based photosensitizers for light-driven killing of bacteria

Flavin-binding fluorescent proteins (FPs) are genetically encoded in vivo reporters, which are derived from microbial and plant LOV photoreceptors. In this study, we comparatively analyzed ROS formation and light-driven antimicrobial efficacy of eleven LOV-based FPs. In particular, we determined singlet oxygen (¹O₂) quantum yields and superoxide photosensitization activities via spectroscopic assays and performed cell toxicity experiments in E. coli. Besides miniSOG and SOPP, which have been engineered to generate ¹O₂, all of the other tested flavoproteins were able to produce singlet oxygen and/or hydrogen peroxide but exhibited remarkable differences in ROS selectivity and yield. Accordingly, most LOV-FPs are potent photosensitizers, which can be used for light-controlled killing of bacteria. Furthermore, the two variants Pp2FbFP and DsFbFP M49I, exhibiting preferential photosensitization of singlet oxygen or singlet oxygen and superoxide, respectively, were shown to be new tools for studying specific ROS-induced cell signaling processes. The tested LOV-FPs thus further expand the toolbox of optogenetic sensitizers usable for a broad spectrum of microbiological and biomedical applications.

Silica/Polyethylene Glycol Hybrid Materials Prepared by a Sol-Gel Method and Containing Chlorogenic Acid

Chlorogenic acid (CGA) is a very common dietary polyphenolic compound. CGA is becoming very attractive due to its potential use as preventive and therapeutic agent in many diseases, including cancer. Inorganic/organic hybrid materials are gaining considerable attention in the biomedical field. The sol-gel process provides a useful way to obtain functional organic/inorganic hybrids. The aim of this study was to synthesize silica/polyethylene glycol (PEG) hybrids with different percentages of CGA by sol-gel technique and to investigate their impact on the cancer cell proliferation. Synthesized materials have been chemically characterized through the FTIR spectroscopy and their bioactivity evaluated looking by SEM at their ability to produce a hydroxyapatite layer on their surface upon incubation with simulated body fluid (SBF). Finally, their effects on cell proliferation were studied in cell lines by direct cell number counting, MTT, flow cytometry-based cell-cycle and cell death assays, and immunoblotting experiments. Notably, we found that SiO₂/PEG/CGA hybrids exhibit clear antiproliferative effects in different tumor, including breast cancer and osteosarcoma, cell lines in a CGA dependent manner, but not in normal cells. Overall, our results increase the evidence of CGA as a possible anticancer agent and illustrate the potential for clinical applications of sol-gel synthesized SiO₂/PEG/CGA materials.

Forskolin Sensitizes Human Acute Myeloid Leukemia Cells to H3K27me2/3 Demethylases GSKJ4 Inhibitor via Protein Kinase A

Acute myeloid leukemia (AML) is an aggressive hematological malignancy occurring very often in older adults, with poor prognosis depending on both rapid disease progression and drug resistance occurrence. Therefore, new therapeutic approaches are demanded. Epigenetic marks play a relevant role in AML. GSKJ4 is a novel inhibitor of the histone demethylases JMJD3 and UTX. To note GSKJ4 has been recently shown to act as a potent small molecule inhibitor of the proliferation in many cancer cell types. On the other hand, forskolin, a natural cAMP raising compound, used for a long time in traditional medicine and considered safe also in recent studies, is emerging as a very interesting molecule for possible use in cancer therapy. Here, we investigate the effects of forskolin on the sensitivity of human leukemia U937 cells to GSKJ4 through flow cytometry-based assays (cell-cycle progression and cell death), cell number counting, and immunoblotting experiments. We provide evidence that forskolin markedly potentiates GSKJ4-induced antiproliferative effects by apoptotic cell death induction, accompanied by a dramatic BCL2 protein down-regulation as well as caspase 3 activation and PARP protein cleavage. Comparable effects are observed with the phosphodiesterase inhibitor IBMX and 8-Br-cAMP analogous, but not by using 8-pCPT-2'-O-Me-cAMP Epac activator. Moreover, the forskolin-induced enhancement of sensitivity to GSKJ4 is counteracted by pre-treatment with Protein Kinase A (PKA) inhibitors. Altogether, our data strongly suggest that forskolin sensitizes U937 cells to GSKJ4 inhibitor via a cAMP/PKA-mediated mechanism. Our findings provide initial evidence of anticancer activity induced by forskolin/GSKJ4 combination in leukemia cells and underline the potential for use of forskolin and GSKJ4 in the development of innovative and effective therapeutic approaches for AML treatment.

Zoledronic acid induces micronuclei formation, mitochondrial-mediated apoptosis and cytostasis in kidney cells

AIMS

Zoledronic acid (ZA), a FDA approved drug has used widely in the treatment of bone metastasis complications, has been linked to renal toxicity with unclear mechanism. The present study is aimed at investigating the genotoxic and cytotoxic effects of ZA in renal epithelial cells.

MAIN METHODS

The genotoxic effect of ZA in Vero and MDCK cells determined by cytokinesis block micronucleus (CBMN) assay. The cytotoxic effect assessed by analysing cell cycle profile, cell death and mitochondrial membrane potential by flow cytometry using propidium iodide, AnnexinV-FITC/PI and JC1 dye staining, respectively, BAX and Bcl-2 expression by Western blotting and caspase activity by spectrofluorimetry.

KEY FINDINGS

The cytotoxic effect of ZA based on MTT assay revealed variable sensitivities of Vero and MDCK cells, with IC₅₀ values of 7.41 and 109.58 μM, respectively. The CBMN assay has shown prominent dose-dependent (IC_10-50) induction of micronuclei formation in both cells, indicating ZA's clastogenic and aneugenic potential. Further, the ZA treatment led the cells to apoptosis, evident from dose-dependent increase in the percentage of cells in subG1 phase and display of membranous phosphatidylserine translocation. Studies also confirmed apoptosis through mitochondria, evident from the prominent increase in BAX/Bcl-2 ratio, mitochondrial membrane depolarization and caspase-3/7 activity. In addition, ZA reduces cytokinetic activity of renal cells, evident from dose-wise lowered replicative indices.

SIGNIFICANCE

The study depict ZA's potential genotoxic effect along with cytotoxic effect in renal epithelial cells, could be key factors for the development of renal complications associated with it, which prompts renal safety measures in lieu with ZA usage.

An Image-based Assay for High-throughput Analysis of Cell Proliferation and Cell Death of Adherent Cells

In this protocol, we describe a method to monitor cell proliferation and death by live-cell imaging of propidium iodide (PI)-stained adherent mammalian cells. PI is widely used to assess cell death. However, it is usually used in end-point assays. Recently, we implemented the use of PI for real-time cell death assessment by automated imaging. Cells are seeded in a 96-well format, and after attachment, the treatments are added directly to the wells together with PI. Thereafter, cells are subjected to automated time-lapse imaging and quantification by computer software. Combined analyses of phase-contrast and fluorescence images allow assessment of treatment effects on cell proliferation as well as the extent and kinetics of cell death.

Chasing the signaling run by tri-molecular time-lapse FRET microscopy

A feasible design is made to measure three protein/protein interactions to visualize signal pathways by time-lapse Förster resonance energy transfer (FRET) microscopy. When interacting proteins are in close proximity, excitation energy is provided to allow the energy flow from the first molecule to excite the second, followed by energy transfer to the third. By phorbol ester/calcium ionophore stimulation, for example, a real-time complex formation of ectopic IκBα/ERK/WWOX occurs as measured by FRET microscopy, indicative of an ongoing functional signaling. Hyaluronan induces membrane Hyal-2 signaling, which allows FRET measurement of the complex formation of ectopic Smad4/WWOX/Hyal-2 for causing bubbling cell death. If ectopic p53 is recruited to replace Hyal-2, the resulting ectopic Smad4/WWOX/p53 complex induces membrane blebbing without cell death. Together, in this perspective review article, we demonstrate the utilization of time-lapse FRET microscopy to visualize the signaling event via the tri-molecular protein complex formation and their biological outcomes. We show an initial two-protein binding to form the driving force to jumpstart the tri-molecular execution for the signal pathway.