Melatonin prevents oxidative stress,inflammatory activity,and DNA damage in cirrhotic rats

BACKGROUND Cirrhosis is an important health problem characterized by a significant change in liver parenchyma.In animals,this can be reproduced by an experimental model of bile duct ligation(BDL).Melatonin(MLT)is a physiological hormone synthesized from serotonin that has been studied for its beneficial properties,including its antioxidant potential.AIM To evaluate MLT’s effects on oxidative stress,the inflammatory process,and DNA damage in an experimental model of secondary biliary cirrhosis.METHODS Male Wistar rats were divided into 4 groups:Control(CO),CO+MLT,BDL,and BDL+MLT.MLT was administered(20 mg/kg)daily beginning on day 15 after biliary obstruction.On day 29 the animals were killed.Blood samples,liver tissue,and bone marrow were collected for further analysis.RESULTS BDL caused changes in biochemical and histological parameters and markers of inflammatory process.Thiobarbituric acid(0.46±0.01)reactive substance levels,superoxide dismutase activity(2.30±0.07)and nitric oxide levels(2.48±0.36)were significantly lower(P<0.001)n the groups that received MLT.DNA damage was also lower(P<0.001)in MLT-treated groups(171.6±32.9)than the BDL-only group(295.5±34.8).Tissue damage and the expression of nuclear factor kappa B,interleukin-1β,Nrf2,NQO1 and Hsp70 were significantly lower in animals treated with MLT(P<0.001).CONCLUSION When administered to rats with BDL-induced secondary biliary cirrhosis,MLT effectively restored the evaluated parameters.

Extracellular matrix-templating fibrous hydrogels promote ovarian tissue remodeling and oocyte growth

Synthetic matrices which mimic the extracellular composition of native tissue create a comprehensive model for studying development and disease.Here,we have engineered a composite material which retains cell-secreted ECM for the culture of ovarian follicles by embedding electrospun dextran fibers functionalized with basement membrane binder(BMB)peptide in PEG hydrogels.In the presence of ECM-sequestering fibers,encapsulated immature primordial follicles and ovarian stromal cells aggregated into large organoid-like structures with dense deposition of laminin,perlecan,and collagen I,leading to steroidogenesis and significantly greater rates of oocyte survival and growth.We determined that cell aggregation restored key cell-cell interactions critical for oocyte survival,whereas oocyte growth was dependent on cell-matrix interactions achieved in the presence of BMB.Here we have shown that sequestration and retention of cell-secreted ECM along synthetic fibers mimics fibrous ECM structure and restores the cell-cell and cell-matrix interactions critical for engineering an artificial ovary.

Compressive Stress Enhances Invasive Phenotype of Cancer Cells via Piezo1 Activation

In this study,we hypothesized that Piezo 1 channels mediate the compression-enhanced invasive phenotype of cancer cells via a caveolae-dependent mechanism.To test this hypothesis,we examined in vitro cultured human breast cancer cells for their ability to invade and degrade extracellular matrix in the presence or absence of compressive stress,together with corresponding changes in Piezo1 as well as cytoskeletal remodeling and calcium signaling.Here we show that compressive stress enhanced invasion,matrix degradation,and invadopodia formation of breast cancer cells.We further identified Piezo1 as the putative mechanosensitive cellular component that transmits compression to induce calcium influx,which in turn triggers several downstream pathways.Interestingly,for the first time we observed inv-adopodia with matrix degradation ability on the apical side of the cells, similar to those commonly observed at the cell s ventral side.Furthermore,we demonstrate that Piezo1 and caveolae were both involved in mediating the compressive stress-induced cancer cell invasive phenotype as Piezo 1 and caveolae were often colocalized,and reduction of Cav-1 expression or disruption of caveolae with methyl-β-cyclodextrin led to not only reduced Piezo1 expression but also attenuation of the invasive phenotypes promoted by compressive stress.Taken together,we first observed that in breast cancer cells,simulating uncontrolled growth-induced compressive stress enhanced cancer cell invasion,matrix degradation,and invadopodia and stress fiber formation.Our study also confirmed that Piezo1 channels are highly expressed in breast cancer cells compared to normal breast cells,and is consistent with the data that compressive stress regulates cell migration of breast cancer cells but not normal breast cells.Additionally,we identified that Piezol mediated these processes and the invasive phenotypes also depended on the integrity of caveolae.These findings provide the first demonstration that compressive stress enhances matrix degradation by breast cancer cells and Piezo1 is an essential mechanosensor and transducer for such stress in breast cancer.Additionally,our data supports the model where caveolae might be the'mechanical force foci'which concentrates Piezol to facilitate force sensing and transduction in mammalian cells.Our work may have relevance to human tumors in vivo.As solid tumor experiences high compressive stress due to uncontrolled proliferation and confinement by the stiff extracellular matrix environment,this microenvironment facilitates compression-enhanced cell invasion.The identification of Piezo1’s crucial role in this process provides the first demonstration of the dependence of Piezo1 channels on the response of breast cancer cells to physiological compressive stress.The functional dependence of Piezo1 on caveolae further highlights the importance of membrane organization and composition on forcegated ion channels.Both of these findings underscore the cardinal role that Piezo1 channels play in regulating cell invasion and may inspire further development targeting Piezol as a potential cancer therapeutic target.

Changing the paradigm：the potential for targeted therapy in laryngeal squamous cell carcinoma

Laryngeal squamous cell carcinoma(LSCC) remains a highly morbid and fatal disease. Historically, it has been a model example for organ preservation and treatment stratification paradigms. Unfortunately, survival for LSCC has stagnated over the past few decades. As the era of next-generation sequencing and personalized treatment for cancer approaches, LSCC may be an ideal disease for consideration of further treatment stratification and personalization. Here, we will discuss the important history of LSCC as a model system for organ preservation, unique and potentially targetable genetic signatures of LSCC, and methods for bringing stratified, personalized treatment strategies to the 21^(st) century.

Synergistic and non-specific nucleic acid production by T7 RNA polymerase and Bsu DNA polymerase catalyzed by single-stranded polynucleotides

Point-of-care molecular diagnostic tests show great promise for providing accurate,timely results in lowinfrastructure healthcare settings and at home.The design space for these tests is limited by a variety of possible background reactions,which often originate from relatively weak promiscuous activities of the enzymes used for nucleic acid amplification.When this background signal is amplified alongside the signal of the intended biomarker,the dynamic range of the test can be severely compromised.Therefore,a detailed knowledge of potential side reactions arising from enzyme promiscuity can improve rational design of point-of-care molecular diagnostic tests.Towards this end,we report a previously unknown synergistic reaction between T7 RNA polymerase and Bsu DNA polymerase that produces nucleic acid in the presence of single-stranded DNA or RNA.This reaction occurs in the absence of any previously reported substrates for either polymerases and compromises a theoretical microRNA amplification scheme utilizing these polymerases.