Understanding the Impact of SARS-CoV-2 on Lung Endothelial Cells: Brief Mechanisms Unveiled.

As the world grapples with the coronavirus-19 (COVID) pandemic, more reports are coming in regarding Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in endotheliopathy. It is a vascular condition in which endothelial cell injury or damage inflicts anatomical and functional changes in the endothelium, significantly impacting the physiological process and function. Previously, it was assumed that SARS-CoV-2 infects respiratory epithelial cells via spike glycoproteins present on the surface of the virus. However, severe cases and different autopsy studies described the clandestine role of this virus in infecting endothelial cells other than epithelial cells. It was observed that SARS-CoV-2 targets the pulmonary and extrapulmonary systems to damage the microvasculature and affect respiratory functioning, resulting in the onset of endotheliopathy, thrombosis, inflammation, pulmonary edema, and fibrosis. Such deleterious events are the consequence of the hyperactive immune response initiated by the SARS-CoV-2 infection, leading to pulmonary and extrapulmonary complications. However, the molecular mechanism behind endotheliopathy and other complications caused by this virus is elusive and will be unraveled by covering recent literature in this mini-review.

Short-term buoyant microplastic transport patterns driven by wave evolution, breaking, and orbital motion in coast.

Recently, there has been a notable rise in social and scientific interest regarding microplastic pollution in coasts where waves significantly influence flow patterns and material transport. This study explores typical short-term movement of buoyant microplastics driven by surf zone processes including wave transformation, breaking, and orbital motion. To track microplastics, Lagrangian Particle Tracking Model (PTM) coupled with Eulerian wave-current interaction model appropriate for coastal hydrodynamics was used. From the simulations, several important findings were observed. (i) In alongshore uniform beaches, lighter and larger buoyant microplastics tended to reach beach more readily. (ii) Accurate predictions of microplastic transport in the surf zone required the consideration of wave breaking. (iii) In alongshore non-uniform coastal bathymetry, rip-currents can send buoyant microplastics offshore, beyond the surf zone.

Stem Cell-based therapies for COVID-19-related acute respiratory distress syndrome.

As the number of confirmed cases and resulting death toll of the COVID-19 pandemic continue to increase around the globe - especially with the emergence of new mutations of the SARS-CoV-2 virus in addition to the known alpha, beta, gamma, delta and omicron variants - tremendous efforts continue to be dedicated to the development of interventive therapeutics to mitigate infective symptoms or post-viral sequelae in individuals for which vaccines are not accessible, viable or effective in the prevention of illness. Many of these investigations aim to target the associated acute respiratory distress syndrome, or ARDS, which induces damage to lung epithelia and other physiologic systems and is associated with progression in severe cases. Recently, stem cell-based therapies have demonstrated preliminary efficacy against ARDS based on a number of preclinical and preliminary human safety studies, and based on promising outcomes are now being evaluated in phase II clinical trials for ARDS. A number of candidate stem cell therapies have been found to exhibit low immunogenicity, coupled with inherent tropism to injury sites. In recent studies, these have demonstrated the ability to modulate suppression of pro-inflammatory cytokine signals such as those characterizing COVID-19-associated ARDS. Present translational studies are aiming to optimize the safety, efficacy and delivery to fully validate stem cell-based strategies targeting COVID-19 associated ARDS for viable clinical application.

TJP1 Contributes to Tumor Progression through Supporting Cell-Cell Aggregation and Communicating with Tumor Microenvironment in Leiomyosarcoma.

Leiomyosarcoma (LMS) is a mesenchymal malignancy with a complex karyotype. Despite accumulated evidence, the factors contributing to the development of LMS are unclear. Here, we investigated the role of tight-junction protein 1 (TJP1), a membrane-associated intercellular barrier protein during the development of LMS and the tumor microenvironment. We orthotopically transplanted SK-LMS-1 cells and their derivatives in terms of TJP1 expression by intramuscular injection, such as SK-LMS-1 Sh-Control cells and SK-LMS-1 Sh-TJP1. We observed robust tumor growth in mice transplanted with LMS cell lines expressing TJP1 while no tumor mass was found in mice transplanted with SK-LMS-1 Sh-TJP1 cells with silenced TJP1 expression. Tissues from mice were stained and further analyzed to clarify the effects of TJP1 expression on tumor development and the tumor microenvironment. To identify the TJP1-dependent factors important in the development of LMS, genes with altered expression were selected in SK-LMS-1 cells such as cyclinD1, CSF1 and so on. The top 10% of highly expressed genes in LMS tissues were obtained from public databases. Further analysis revealed two clusters related to cell proliferation and the tumor microenvironment. Furthermore, integrated analyses of the gene expression networks revealed correlations among TJP1, CSF1 and CTLA4 at the mRNA level, suggesting a possible role for TJP1 in the immune environment. Taken together, these results imply that TJP1 contributes to the development of sarcoma by proliferation through modulating cell-cell aggregation and communication through cytokines in the tumor microenvironment and might be a beneficial therapeutic target.

Anti-Tumor Effects of Sodium Meta-Arsenite in Glioblastoma Cells with Higher Akt Activities.

Glioblastoma is a type of aggressive brain tumor that grows very fast and evades surrounding normal brain, lead to treatment failure. Glioblastomas are associated with Akt activation due to somatic alterations in PI3 kinase/Akt pathway and/or PTEN tumor suppressor. Sodium meta-arsenite, KML001 is an orally bioavailable, water-soluble, and trivalent arsenical and it shows antitumoral effects in several solid tumor cells via inhibiting oncogenic signaling, including Akt and MAPK. Here, we evaluated the effect of sodium meta-arsenite, KML001, on the growth of human glioblastoma cell lines with different PTEN expression status and Akt activation, including PTEN-deficient cells (U87-MG and U251) and PTEN-positive cells (LN229). The growth-inhibitory effect of KML001 was stronger in U87-MG and U251 cells, which exhibited higher Akt activity than LN229 cells. KML001 deactivated Akt and decreased its protein levels via proteasomal degradation in U87-MG cells. KML001 upregulated mutant PTEN levels via inhibition of its proteasomal degradation. KML001 inhibited cell growth more effectively in active Akt-overexpressing LN229 cells than in mock-expressing LN229 cells. Consistent with these results, KML001 sensitized PTEN-deficient cells more strongly to growth inhibition than it did PTEN-positive cells in prostate and breast cancer cell lines. Finally, we illustrated in vivo anti-tumor effects of KML001 using an intracranial xenograft mouse model. These results suggest that KML001 could be an effective chemotherapeutic drug for the treatment of glioblastoma cancer patients with higher Akt activity and PTEN loss.

Lagrangian-like Volume Tracking Paradigm for Mass, Momentum and Energy of Nearshore Tsunamis and Damping Mechanism.

There is a gap between model- or theory-based research outputs, which suggest that the runup and amplification of nonbreaking waves generally increase as the sea bottom slopes decrease, and field observations, which indicate that tsunami damage has been rarely reported in places with vast continental shelfs. To resolve this contradiction, we propose a Lagrangian-like volume tracking paradigm to describe the energy, mass, and momentum of travelling nearshore tsunamis and apply the paradigm to analyse the tsunami damping mechanism at typical geophysical scales. The results support the following conclusions: (i) The suggested paradigm is consistent with field observations; continental shelfs with long and mild slopes can effectively diminish tsunami impacts. (ii) Potential energy becomes significant due to the energy transformation process on steeply sloped bathymetries. (iii) On mild-sloped bathymetries, tsunami potential and kinetic energies are conserved until breaking occurs. After breaking, undular bores attenuate tsunami energies effectively. (iv) For extended continental shelf bathymetries, more of the tsunami mass is reflected offshore.

The American cockroach peptide periplanetasin-4 inhibits Clostridium difficile toxin A-induced cell toxicities and inflammatory responses in the mouse gut.

Many reports have shown that crude extracts of the American cockroach have therapeutic effects on inflammation. In a previous study, our research group showed that an antimicrobial peptide (Periplanetasin-2) derived from the American cockroach via de novo transcriptome analysis inhibited apoptosis of human colonocytes and inflammatory responses of the mouse gut caused by Clostridium difficile toxin A. Here, we examined whether Periplanetasin-4 (Peri-4), another antimicrobial peptide identified via de novo transcriptome analysis of the American cockroach, could also inhibit the various toxicities induced by C. difficile toxin A. We found that Peri-4 significantly reduced the cell viability loss and cell apoptosis caused by toxin A in vitro. Peri-4 also ameliorated the severe inflammatory responses seen in the toxin A-induced mouse enteritis model, rescuing the villus disruption and interleukin-6 production induced by luminal injection of toxin A into the mouse gut. Mechanistically, we found that Peri-4 could reduce toxin A-induced reactive oxygen species production to inhibit the activations of p38MAPK and p21Cip1/Waf1 , which are critical for the cell damages induced by toxin A. These results collectively suggest that the Peri-4 may be a potential therapeutic agent for treating toxin A-induced pseudomembranous colitis. Copyright © 2017 European Peptide Society and John Wiley & Sons, Ltd.

Intense focused ultrasound (IFUS) with a modified parameter on facial tightening: A study on its safety and efficacy.

BACKGROUND: Intense focused ultrasound (IFUS) is a novel treatment modality for skin laxity. The delivery of thermal energy to the deeper tissue layers effectively tightens the skin but can also cause significant fat atrophy, limiting its use in patients with a lean face. OBJECTIVES: We sought to evaluate the safety and efficacy of modified IFUS on facial rejuvenation. PATIENTS AND METHODS: This was a retrospective, single-center study of 28 subjects with age-related facial laxity who underwent 3 sessions of IFUS (UltraskinTM, WONTECH Co., Daejeon, Korea) at an interval of four weeks, and then followed up for three months. IFUS was first applied using a 4-MHZ, 4.5-mm transducer followed by a 7-MHZ, 3-mm transducer. Approximately 200-300 treatment lines were applied to the face during each session. Standardized photographs were taken at baseline and follow-ups and were assessed by two independent dermatologists. A questionnaire was used to evaluate patient satisfaction and the incidence of adverse reactions. RESULTS: Twenty-eight subjects with mild-to-moderate age-related facial laxity were included in the study. The mean age of the subjects was 48 (range 29-74) years. About 32.1% of the subjects showed significant improvement and 57.1% showed improvement of facial laxity in their follow-up photographs. All of them (100%) replied that they were either greatly satisfied or satisfied with the results at three-month follow-up. None of the subjects experienced any serious adverse events including fat atrophy after the procedure. CONCLUSION: Modified IFUS (three sessions, four weeks apart, 200-300 treatment lines per session) can be safely performed with good clinical results.

NQO1-Knockout Mice Are Highly Sensitive to Clostridium Difficile Toxin A-Induced Enteritis.

Clostridium difficile toxin A causes acute gut inflammation in animals and humans. It is known to downregulate the tight junctions between colonic epithelial cells, allowing luminal contents to access body tissues and trigger acute immune responses. However, it is not yet known whether this loss of the barrier function is a critical factor in the progression of toxin A-induced pseudomembranous colitis. We previously showed that NADH:quinone oxidoreductase 1 (NQO1) KO (knockout) mice spontaneously display weak gut inflammation and a marked loss of colonic epithelial tight junctions. Moreover, NQO1 KO mice exhibited highly increased inflammatory responses compared with NQO1 WT (wild-type) control mice when subjected to DSS-induced experimental colitis. Here, we tested whether toxin A could also trigger more severe inflammatory responses in NQO1 KO mice compared with NQO1 WT mice. Indeed, our results show that C. difficile toxin A-mediated enteritis is significantly enhanced in NQO1 KO mice compared with NQO1 WT mice. The levels of fluid secretion, villus disruption, and epithelial cell apoptosis were also higher in toxin A-treated NQO1 KO mice compared with WT mice. The previous and present results collectively show that NQO1 is involved in the formation of tight junctions in the small intestine, and that defects in NQO1 enhance C. difficile toxin A-induced acute inflammatory responses, presumably via the loss of epithelial cell tight junctions.

Potassium Acetate Blocks Clostridium difficile Toxin A-Induced Microtubule Disassembly by Directly Inhibiting Histone Deacetylase 6, Thereby Ameliorating Inflammatory Responses in the Gut.

Clostridium difficile toxin A is known to cause deacetylation of tubulin proteins, which blocks microtubule formation and triggers barrier dysfunction in the gut. Based on our previous finding that the Clostridium difficile toxin A-dependent activation of histone deacetylase 6 (HDAC-6) is responsible for tubulin deacetylation and subsequent microtubule disassembly, we herein examined the possible effect of potassium acetate (PA; whose acetyl group prevents the binding of tubulin to HDAC-6) as a competitive/false substrate. Our results revealed that PA inhibited toxin A-induced deacetylation of tubulin and recovered toxin A-induced microtubule disassembly. In addition, PA treatment significantly decreased the production of IL-6 (a marker of inflamed tissue) in the toxin A-induced mouse enteritis model. An in vitro HDAC assay revealed that PA directly inhibited HDAC-6-mediated tubulin deacetylation, indicating that PA acted as a false substrate for HDAC-6. These results collectively indicate that PA treatment inhibits HDAC-6, thereby reducing the cytotoxicity and inflammatory responses caused by C. difficile toxin A.

The Insect Peptide CopA3 Increases Colonic Epithelial Cell Proliferation and Mucosal Barrier Function to Prevent Inflammatory Responses in the Gut.

The epithelial cells of the gut form a physical barrier against the luminal contents. The collapse of this barrier causes inflammation, and its therapeutic restoration can protect the gut against inflammation. EGF enhances mucosal barrier function and increases colonocyte proliferation, thereby ameliorating inflammatory responses in the gut. Based on our previous finding that the insect peptide CopA3 promotes neuronal growth, we herein tested whether CopA3 could increase the cell proliferation of colonocytes, enhance mucosal barrier function, and ameliorate gut inflammation. Our results revealed that CopA3 significantly increased epithelial cell proliferation in mouse colonic crypts and also enhanced colonic epithelial barrier function. Moreover, CopA3 treatment ameliorated Clostridium difficile toxin As-induced inflammation responses in the mouse small intestine (acute enteritis) and completely blocked inflammatory responses and subsequent lethality in the dextran sulfate sodium-induced mouse model of chronic colitis. The marked CopA3-induced increase of colonocyte proliferation was found to require rapid protein degradation of p21(Cip1/Waf1), and an in vitro ubiquitination assay revealed that CopA3 directly facilitated ubiquitin ligase activity against p21(Cip1/Waf1). Taken together, our findings indicate that the insect peptide CopA3 prevents gut inflammation by increasing epithelial cell proliferation and mucosal barrier function.

Antimicrobial Peptide, Lumbricusin, Ameliorates Motor Dysfunction and Dopaminergic Neurodegeneration in a Mouse Model of Parkinson's Disease.

We recently reported that the antimicrobial peptide Lumbricusin (NH2-RNRRWCIDQQA), isolated from the earthworm, increases cell proliferation in neuroblastoma SH-SY5Y cells. Here, we investigated whether Lumbricusin has neurotropic activity in mouse neural stem cells (MNSCs) and a protective effect in a mouse model of Parkinson's disease (PD). In MNSCs isolated from mouse brains, Lumbricusin treatment significantly increased cell proliferation (up to 12%) and reduced the protein expression of p27(Kip1) through proteasomal protein degradation but not transcriptional regulation. Lumbricusin inhibited the 6-OHDA-induced apoptosis of MNSCs, and also showed neuroprotective effects in a mouse PD model, ameliorating the motor impairments seen in the pole, elevated body swing, and rotation tests. These results suggest that the Lumbricusin-induced promotion of neural cell proliferation via p27(Kip1) degradation has a protective effect in an experimental PD model. Thus, the antimicrobial peptide Lumbricusin could possibly be developed as a potential therapeutic agent for the treatment of PD.

Neurotropic and neuroprotective activities of the earthworm peptide Lumbricusin.

We recently isolated a polypeptide from the earthworm Lumbricus terrestris that is structurally similar to defensin, a well-known antibacterial peptide. An 11-mer antibacterial peptide (NH2-RNRRWCIDQQA), designated Lumbricusin, was synthesized based on the amino acid sequence of the isolated polypeptide. Since we previously reported that CopA3, a dung beetle peptide, enhanced neuronal cell proliferation, we here examined whether Lumbricusin exerted neurotropic and/or neuroprotective effects. Lumbricusin treatment induced a time-dependent increase (∼51%) in the proliferation of human neuroblastoma SH-SY5Y cells. Lumbricusin also significantly inhibited the apoptosis and decreased viability induced by treatment with 6-hydroxy dopamine, a Parkinson's disease-mimicking agent. Immunoblot analyses revealed that Lumbricusin treatment increased ubiquitination of p27(Kip1) protein, a negative regulator of cell-cycle progression, in SH-SY5Y cells, and markedly promoted its degradation. Notably, adenoviral-mediated over-expression of p27(Kip1) significantly blocked the antiapoptotic effect of Lumbricusin in 6-hydroxy dopamine-treated SH-SY5Y cells. These results suggest that promotion of p27(Kip1) degradation may be the main mechanism underlying the neuroprotective and neurotropic effects of Lumbricusin.

Effect of antisera from Clostridium difficile-infected mice on toxin-A-induced colonic epithelial cell death signaling.

Clostridium difficile causes mucosal damage and diarrhea by releasing two exotoxins: toxin A and toxin B. C. difficile colitis is associated with alterations in bowel flora and the failure to mount an effective antibody response. The aim of the current study was to investigate whether antitoxin sera prevent toxin-A-induced apoptosis, cytoskeletal disaggregation, cell detachment, and tight junction loss in cultured colonic epithelial cells. Serum samples were isolated from mice that survived a C. difficile infection following antibiotic treatment, and the antitoxin effects of these samples were investigated in toxin-A-exposed HT29 colonic epithelial cells and a toxin-A-induced animal model of gut inflammation. Unchallenged mice did not produce IgG against toxin A, whereas serum (antiserum) from C. difficile-challenged mice showed significant IgG responses against toxin A. Treatment with the antiserum markedly inhibited mucosal damage and inflammation in the toxin-A-treated mouse model. In contrast to control mouse serum, the antiserum also markedly inhibited toxin-A-induced DNA fragmentation, dephosphorylation of paxillin and Epo receptor (EpoR), deacetylation of tubulin, and upregulation of p21(WAF1/CIP1) and p53. Taken together, these results reveal that the generated antitoxin serum has biotherapeutic effects in preventing various C. difficile toxin-A-induced cellular toxicities.

Role of NADH: quinone oxidoreductase-1 in the tight junctions of colonic epithelial cells.

NADH:quinone oxidoreductase 1 (NQO1) is known to be involved in the regulation of energy synthesis and metabolism, and the functional studies of NQO1 have largely focused on metabolic disorders. Here, we show for the first time that compared to NQO1-WT mice, NQO1-KO mice exhibited a marked increase of permeability and spontaneous inflammation in the gut. In the DSS-induced colitis model, NQO1-KO mice showed more severe inflammatory responses than NQO1-WT mice. Interestingly, the transcript levels of claudin and occludin, the major tight junction molecules of gut epithelial cells, were significantly decreased in NQO1-KO mice. The colons of NQO1-KO mice also showed high levels of reactive oxygen species (ROS) and histone deacetylase (HDAC) activity, which are known to affect transcriptional regulation. Taken together, these novel findings indicate that NQO1 contributes to the barrier function of gut epithelial cells by regulating the transcription of tight junction molecules.

Insect peptide CopA3-induced protein degradation of p27Kip1 stimulates proliferation and protects neuronal cells from apoptosis.

We recently demonstrated that the antibacterial peptide, CopA3 (a D-type disulfide dimer peptide, LLCIALRKK), inhibits LPS-induced macrophage activation and also has anticancer activity in leukemia cells. Here, we examined whether CopA3 could affect neuronal cell proliferation. We found that CopA3 time-dependently increased cell proliferation by up to 31 ± 2% in human neuroblastoma SH-SY5Y cells, and up to 29 ± 2% in neural stem cells isolated from neonatal mouse brains. In both cell types, CopA3 also significantly inhibited the apoptosis and viability losses caused by 6-hydroxy dopamine (a Parkinson disease-mimicking agent) and okadaic acid (an Alzheimer's disease-mimicking agent). Immunoblotting revealed that the p27Kip1 protein (a negative regulator of cell cycle progression) was markedly degraded in CopA3-treated SH-SY5Y cells. Conversely, an adenovirus expressing p27Kip1 significantly inhibited the antiapoptotic effects of CopA3 against 6-hydroxy dopamine- and okadaic acid-induced apoptosis, and decreased the neurotropic effects of CopA3. These results collectively suggest that CopA3-mediated protein degradation of p27Kip1 may be the main mechanism through which CopA3 exerts neuroprotective and neurotropic effects.

Cytosine deaminase-expressing human neural stem cells inhibit tumor growth in prostate cancer-bearing mice.

Prostate cancer is the most common malignancy among men. Prostate cancer-related deaths are largely attributable to the development of hormone resistance in the tumor. No effective chemotherapy has yet been developed for advanced prostate cancer. It is desirable if a drug can be delivered directly and specifically to prostate cancer cells. Stem cells have selective migration ability toward cancer cells and therapeutic genes can be easily transduced into stem cells. In one form of gene therapy for cancer, the stem cells carry a gene encoding an enzyme that transforms an inert prodrug into a toxic product. Cytosine deaminase (CD) transforms the pro-drug 5-fluorocytosine into highly cytotoxic 5-fluorouracil (5-FU). The migration of the genetically modified stem cells was monitored by molecular magnetic resonance imaging, after labeling the stem cells with fluorescent magnetic nanoparticles (MNPs). Human neural stem cells encoding CD (HB1.F3.CD) were prepared and labeled with MNP. In tumor-bearing C57B mice, systemically transplanted HB1.F3.CD stem cells migrated toward the tumor and in combination with prodrug 5-FC, the volume of tumor implant was significantly reduced. These findings may contribute to development of a new selective chemotherapeutic strategy against prostate cancer.