Integrin activation by a cold atmospheric plasma jet

Current breakthrough research on cold atmospheric plasma (CAP) demonstrates that CAP has great potential in various areas, including medicine and biology, thus providing a new tool for living tissue treatment. In this paper, we explore potential mechanisms by which CAP alters cell migration and influences cell adhesion. We focus on the study of CAP interaction with fibroblasts and corneal epithelial cells. The data show that fibroblasts and corneal epithelial cells have different thresholds (treatment times) required to achieve maximum inhibition of cell migration. Both cell types reduced their migration rates by ~30–40% after CAP compared to control cells. Also, the impact of CAP treatment on cell migration and persistence of fibroblasts after integrin activation by MnCl2, serum starvation or replating cells onto surfaces coated with integrin ligands is assessed; the results show that activation by MnCl2 or starvation attenuates cells\u27 responses to plasma. Studies carried out to assess the impact of CAP treatment on the activation state of β1 integrin and focal adhesion size by using immunofluorescence show that fibroblasts have more active β1 integrin on their surface and large focal adhesions after CAP treatment. Based on these data, a thermodynamic model is presented to explain how CAP leads to integrin activation and focal adhesion assembly

Cold Atmospheric Plasma Inhibits HIV-1 Replication in Macrophages by Targeting Both the Virus and the Cells.

Cold atmospheric plasma (CAP) is a specific type of partially ionized gas that is less than 104°F at the point of application. It was recently shown that CAP can be used for decontamination and sterilization, as well as anti-cancer treatment. Here, we investigated the effects of CAP on HIV-1 replication in monocyte-derived macrophages (MDM). We demonstrate that pre-treatment of MDM with CAP reduced levels of CD4 and CCR5, inhibiting virus-cell fusion, viral reverse transcription and integration. In addition, CAP pre-treatment affected cellular factors required for post-entry events, as replication of VSV-G-pseudotyped HIV-1, which by-passes HIV receptor-mediated fusion at the plasma membrane during entry, was also inhibited. Interestingly, virus particles produced by CAP-treated cells had reduced infectivity, suggesting that the inhibitory effect of CAP extended to the second cycle of infection. These results demonstrate that anti-HIV activity of CAP involves the effects on target cells and the virus, and suggest that CAP may be considered for potential application as an anti-HIV treatment

Targeting the cancer cell cycle by cold atmospheric plasma

Cold atmospheric plasma (CAP), a technology based on quasi-neutral ionized gas at low temperatures, is currently being evaluated as a new highly selective alternative addition to existing cancer therapies. Here, we present a first attempt to identify the mechanism of CAP action. CAP induced a robust ~2-fold G2/M increase in two different types of cancer cells with different degrees of tumorigenicity. We hypothesize that the increased sensitivity of cancer cells to CAP treatment is caused by differences in the distribution of cancer cells and normal cells within the cell cycle. The expression of γH2A.X (pSer139), an oxidative stress reporter indicating S-phase damage, is enhanced specifically within CAP treated cells in the S phase of the cell cycle. Together with a significant decrease in EdU-incorporation after CAP, these data suggest that tumorigenic cancer cells are more susceptible to CAP treatment

Differential Effects of Cold Atmospheric Plasma in the Treatment of Malignant Glioma

Objective Cold atmospheric plasma (CAP) has recently been shown to selectively target cancer cells with minimal effects on normal cells. We systematically assessed the effects of CAP in the treatment of glioblastoma. Methods Three glioma cell lines, normal astrocytes, and endothelial cell lines were treated with CAP. The effects of CAP were then characterized for viability, cytotoxicity/apoptosis, and cell cycle effects. Statistical significance was determined with student\u27s t-test. Results CAP treatment decreases viability of glioma cells in a dose dependent manner, with the ID50 between 90-120 seconds for all glioma cell lines. Treatment with CAP for more than 120 seconds resulted in viability less than 35% at 24-hours posttreatment, with a steady decline to less than 20% at 72-hours. In contrast, the effect of CAP on the viability of NHA and HUVEC was minimal, and importantly not significant at 90 to 120 seconds, with up to 85% of the cells remained viable at 72-hours post-treatment. CAP treatment produces both cytotoxic and apoptotic effects with some variability between cell lines. CAP treatment resulted in a G2/M-phase cell cycle pause in all three cell lines. Conclusions This preliminary study determined a multi-focal effect of CAP on glioma cells in vitro, which was not observed in the non-tumor cell lines. The decreased viability depended on the treatment duration and cell line, but overall was explained by the induction of cytotoxicity, apoptosis, and G2/M pause. Future studies will aim at further characterization with more complex pre-clinical models

Analysis of CAP cytotoxicity.

<p>A. Morphology of MDM after CAP treatment. Macrophages in the CAP-treated area were imaged 1 h and 24 h after treatment (45 sec at 4.5 kV). B. Cell viability was assessed by MTT assay. MTT conversion to formazan was measured at OD₅₇₀.</p

CAP effects on HIV-1 replication.

<p>A. Monocyte-derived macrophages treated with CAP or helium (control) were infected with HIV-1 ADA and viral replication was monitored for 15 days by RT activity in the culture supernatant. B. Results (mean±SD) are presented for RT analysis on day 15 after infection (performed as in panel A) for 7 different donors. ****p<0.0001 by Student’s unpaired two-tail <i>t</i>-test. C. MDM infected with HIV-1 ADA as in A were analyzed 4 h post infection by qPCR for positive-strand cDNA. Cells treated with AZT (3 μM) and uninfected cells are shown as negative controls. Results are presented as mean±SD for four independent infections with cells from one representative donor. ***p = 0.0004 by Student’s unpaired two-tail <i>t</i>-test. D. HIV-infected MDM were analyzed 48 h post-infection by Alu-GAG qPCR for integrated proviral DNA. Results are presented as mean±SD for four independent infections with cells from one representative donor. *p = 0.0494 by Student’s unpaired two-tail <i>t</i>-test. E. HIV-1 ADA was treated with CAP or helium (control) and used to infect MDM. Virus infection was assessed by measuring reverse transcriptase activity in culture supernatant on day 10–15 post-infection. Results (mean±SD) are presented for 6 experiments with MDM from independent donors. ***p<0.001 by Student’s unpaired two-tail <i>t</i>-test.</p

Mechanisms of anti-HIV activity of CAP treatment.

<p>A1. MDM treated with CAP or helium (control) were analyzed by flow cytometry for expression of CCR5 and CD4. A2. Results are presented as mean ± SEM for analysis performed for MDM from two donors. P values (relative to control) were calculated using Student’s unpaired two-tail <i>t</i>-test. B. Fusion between HIV-1 and MDM was analyzed by fluorescence resonance energy transfer-based fusion assay. Cleavage of CCF2 represents virus-cell fusion. C. MDM treated with CAP or helium (control) were infected in triplicate wells with HIV-1 ADA (R5 virus) or VSV-G-psudotyped HIV-1 NL4-3 (X4 virus), and viral production was measured on day 7 by RT activity. Results are presented as mean ± SD. *p = 0.0037, **p = 0.027 relative to control, calculated using Student’s unpaired two-tail <i>t</i>-test. D. MDM treated with CAP or helium (control) were infected with HIV-1 ADA and incubated for 21 days. Virus was collected, adjusted to the same RT activity by dilution, and used to infect indicator TZM-bl cells. Results are presented as mean ± SD for 5 independent replicates. ****p<0.0001 by Student’s unpaired two-tail <i>t</i>-test.</p

Synergistic Assembly of Heavy Metal Clusters and Luminescent Organic Bridging Ligands in Metal–Organic Frameworks for Highly Efficient X‑ray Scintillation

We have designed two metal–organic frameworks (MOFs) to efficiently convert X-ray to visible-light luminescence. The MOFs are constructed from M₆(μ₃-O)₄(μ₃-OH)₄(carboxylate)₁₂ (M = Hf or Zr) secondary building units (SBUs) and anthracene-based dicarboxylate bridging ligands. The high atomic number of Zr and Hf in the SBUs serves as effective X-ray antenna by absorbing X-ray photons and converting them to fast electrons through the photoelectric effect. The generated electrons then excite multiple anthracene-based emitters in the MOF through inelastic scattering, leading to efficient generation of detectable photons in the visible spectrum. The MOF materials thus serve as efficient X-ray scintillators via synergistic X-ray absorption by the metal-cluster SBUs and optical emission by the bridging ligands