scholarly journals Cardiac optogenetics

2013 ◽  
Vol 304 (9) ◽  
pp. H1179-H1191 ◽  
Author(s):  
Emilia Entcheva
Keyword(s):  
Ion Channels ◽  
Mammalian Cells ◽  
High Specificity ◽  
Emerging Technology ◽  
Inhibitory Response ◽  
Research Activity ◽  
Spatiotemporal Resolution ◽  
And Control ◽  
The Impact

Optogenetics is an emerging technology for optical interrogation and control of biological function with high specificity and high spatiotemporal resolution. Mammalian cells and tissues can be sensitized to respond to light by a relatively simple and well-tolerated genetic modification using microbial opsins (light-gated ion channels and pumps). These can achieve fast and specific excitatory or inhibitory response, offering distinct advantages over traditional pharmacological or electrical means of perturbation. Since the first demonstrations of utility in mammalian cells (neurons) in 2005, optogenetics has spurred immense research activity and has inspired numerous applications for dissection of neural circuitry and understanding of brain function in health and disease, applications ranging from in vitro to work in behaving animals. Only recently (since 2010), the field has extended to cardiac applications with less than a dozen publications to date. In consideration of the early phase of work on cardiac optogenetics and the impact of the technique in understanding another excitable tissue, the brain, this review is largely a perspective of possibilities in the heart. It covers the basic principles of operation of light-sensitive ion channels and pumps, the available tools and ongoing efforts in optimizing them, overview of neuroscience use, as well as cardiac-specific questions of implementation and ideas for best use of this emerging technology in the heart.

scholarly journals Arabidopsis Myosin XIK Interacts with the Exocyst Complex to Facilitate Vesicle Tethering during Exocytosis

2020 ◽  
Author(s):  
Weiwei Zhang ◽  
Lei Huang ◽  
Chunhua Zhang ◽  
Christopher J. Staiger
Keyword(s):  
Mammalian Cells ◽  
Secretory Vesicle ◽  
Tail Domain ◽  
Spatiotemporal Resolution ◽  
Dynamic Regulation ◽  
Vesicle Tethering ◽  
Exocyst Complex ◽  
Myosin Xi ◽  
Myosin Motors

ABSTRACTMyosin motors are essential players in secretory vesicle trafficking and exocytosis in yeast and mammalian cells; however, similar roles in plants remain a matter for debate, at least for diffusely-growing cells. Here, we demonstrate that Arabidopsis (Arabidopsis thaliana) myosin XIK, via its globular tail domain (GTD), participates in the vesicle tethering step of exocytosis through direct interactions with the exocyst complex. Specifically, myosin XIK GTD bound directly to the SEC5B subunit of exocyst in vitro and functional fluorescently-tagged XIK colocalized with multiple exocyst subunits at plasma membrane (PM)-associated stationary foci. Moreover, genetic and pharmacological inhibition of myosin XI activity reduced the frequency and lifetime of stationary exocyst complexes at the PM. By tracking single exocytosis events of cellulose synthase (CESA) complexes (CSCs) with high spatiotemporal resolution imaging and pair-wise colocalization analysis of myosin XIK, exocyst subunits and CESA6, we demonstrated that XIK associates with secretory vesicles earlier than exocyst and is required for the recruitment of exocyst to the PM tethering site. This study reveals an important functional role for myosin XI in secretion and provides new insights about the dynamic regulation of exocytosis in plants.

scholarly journals Sensing through Non-Sensing Ocular Ion Channels

2020 ◽  
Vol 21 (18) ◽  
pp. 6925
Author(s):  
Meha Kabra ◽  
Bikash Ranjan Pattnaik
Keyword(s):  
Ion Channels ◽  
Visual Processing ◽  
Signal Transmission ◽  
Dominant Negative ◽  
Dominant Negative Effect ◽  
Cone Dystrophy ◽  
Wide Range ◽  
The Impact

Ion channels are membrane-spanning integral proteins expressed in multiple organs, including the eye. In the eye, ion channels are involved in various physiological processes, like signal transmission and visual processing. A wide range of mutations have been reported in the corresponding genes and their interacting subunit coding genes, which contribute significantly to an array of blindness, termed ocular channelopathies. These mutations result in either a loss- or gain-of channel functions affecting the structure, assembly, trafficking, and localization of channel proteins. A dominant-negative effect is caused in a few channels formed by the assembly of several subunits that exist as homo- or heteromeric proteins. Here, we review the role of different mutations in switching a “sensing” ion channel to “non-sensing,” leading to ocular channelopathies like Leber’s congenital amaurosis 16 (LCA16), cone dystrophy, congenital stationary night blindness (CSNB), achromatopsia, bestrophinopathies, retinitis pigmentosa, etc. We also discuss the various in vitro and in vivo disease models available to investigate the impact of mutations on channel properties, to dissect the disease mechanism, and understand the pathophysiology. Innovating the potential pharmacological and therapeutic approaches and their efficient delivery to the eye for reversing a “non-sensing” channel to “sensing” would be life-changing.

DAPI Method: A Novel Assay to Evaluate the In vitro Impact of Nanomaterials on Mammalian Cells

2006 ◽  
Vol 951 ◽  
Author(s):  
Pavan M. V. Raja ◽  
Jennifer Connolley ◽  
Pulickel M. Ajayan ◽  
Omkaram Nalamasu ◽  
Deanna M. Thompson
Keyword(s):  
Image Analysis ◽  
Mammalian Cells ◽  
Biological Impact ◽  
Simple Estimate ◽  
Aortic Smooth Muscle ◽  
Diphenyltetrazolium Bromide ◽  
Wide Range ◽  
The Impact ◽  
Non Destructive

ABSTRACTThe increasing importance of nanomaterial-related applications has given rise to concerns pertaining to their impact on human health. In vitro mammalian cell-based assays can provide a quick and simple estimate of the possible adverse effects of the nanomaterials. However, recent studies have questioned the efficacy of traditional assays such as the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, in evaluating cell-nanomaterial interactions, implying the need for alternate methods. We applied image analysis to enumerate the DAPI (2-[4-(Aminomethyl) phenyl]-1H-indole-6-carboximidamide, dihydrochloride) – stained cellular nuclei. Image analysis, being non-destructive, capable of automation, and applicable over a wide range of cell seeding densities, offers several advantages compared to older methods like the MTT assay and hemocytometry. Using image analysis, the impact of singlewalled carbon nanotubes (SWNT) on rat aortic smooth muscle cell (SMC) growth kinetics, were examined. Despite the carbon nanomaterial presence, the fluorescent signal from the nuclei was not noticeably impacted over the SWNT range examined (0.00-0.10 mg/ml). We anticipate that this method can also be applied to evaluate the biological impact of other nanomaterials.

scholarly journals Polymerase Mu Is a DNA-Directed DNA/RNA Polymerase

2003 ◽  
Vol 23 (7) ◽  
pp. 2309-2315 ◽  
Author(s):  
Stephanie A. Nick McElhinny ◽  
Dale A. Ramsden
Keyword(s):  
High Specificity ◽  
Strand Break ◽  
Double Strand Break ◽  
Nonhomologous End Joining ◽  
Double Strand Break Repair ◽  
End Joining ◽  
Strand Breaks ◽  
Break Repair ◽  
The Impact

ABSTRACT DNA polymerases are defined as such because they use deoxynucleotides instead of ribonucleotides with high specificity. We show here that polymerase mu (pol μ), implicated in the nonhomologous end-joining pathway for repair of DNA double-strand breaks, incorporates both ribonucleotides and deoxynucleotides in a template-directed manner. pol μ has an approximately 1,000-fold-reduced ability to discriminate against ribonucleotides compared to that of the related pol β, although pol μ's substrate specificity is similar to that of pol β in most other respects. Moreover, pol μ more frequently incorporates ribonucleotides when presented with nucleotide concentrations that approximate cellular pools. We therefore addressed the impact of ribonucleotide incorporation on the activities of factors required for double-strand break repair by nonhomologous end joining. We determined that the ligase required for this pathway readily joined strand breaks with terminal ribonucleotides. Most significantly, pol μ frequently introduced ribonucleotides into the repair junctions of an in vitro nonhomologous end-joining reaction, an activity that would be expected to have important consequences in the context of cellular double-strand break repair.

scholarly journals Physical and Functional Interactions between Cellular Retinoic Acid Binding Protein II and the Retinoic Acid-Dependent Nuclear Complex

1999 ◽  
Vol 19 (10) ◽  
pp. 7158-7167 ◽  
Author(s):  
Laurent Delva ◽  
Jean-Noël Bastie ◽  
Cécile Rochette-Egly ◽  
Radhia Kraïba ◽  
Nicole Balitrand ◽  
...  
Keyword(s):  
Retinoic Acid ◽  
Nuclear Receptors ◽  
Mammalian Cells ◽  
Specific Response ◽  
Independent Manner ◽  
Control Of Gene Expression ◽  
Steady State Levels ◽  
And Control

ABSTRACT Two sorts of proteins bind to, and mediate the developmental and homeostatic effects of, retinoic acid (RA): the RAR and RXR nuclear receptors, which act as ligand-dependent transcriptional regulators, and the cellular RA binding proteins (CRABPI and CRABPII). CRABPs are generally known to be implicated in the synthesis, degradation, and control of steady-state levels of RA, yet previous and recent data have indicated that they could play a role in the control of gene expression. Here we show for the first time that, both in vitro and in vivo, CRABPII is associated with RARα and RXRα in a ligand-independent manner in mammalian cells (HL-60, NB-4, and MCF-7). In the nucleus, this protein complex binds the RXR-RAR-specific response element of an RA target gene (RARE-DR5). Moreover, in the presence of retinoids that bind both the nuclear receptors and CRABPII, enhancement of transactivation by RXRα-RARα heterodimers is observed in the presence of CRABPII. Thus, CRABPII appears to be a novel transcriptional regulator involved in RA signaling.

scholarly journals The Effects of Three Chlorhexidine-Based Mouthwashes on Human Osteoblast-Like SaOS-2 Cells. An In Vitro Study

2021 ◽  
Vol 22 (18) ◽  
pp. 9986
Author(s):  
Giulia Brunello ◽  
Kathrin Becker ◽  
Luisa Scotti ◽  
Dieter Drescher ◽  
Jürgen Becker ◽  
...  
Keyword(s):  
Cell Viability ◽  
Cetylpyridinium Chloride ◽  
Control Cell ◽  
In Vitro Study ◽  
Control Group ◽  
Sterile Saline ◽  
Lack Of Information ◽  
And Control ◽  
The Impact

Several decontamination methods for removing biofilm from implant surfaces during surgical peri-implantitis treatment have been reported, including the intraoperative usage of chlorhexidine (CHX)-based antiseptics. There is a lack of information on possible adverse effects on bone healing. The study aimed to examine the impact of three CHX-based mouthwashes on osteoblast-like cells (SaOS-2) in vitro. Cells were cultured for three days in 96-well binding plates. Each well was randomly treated for either 30, 60 or 120 s with 0.05% CHX combined with 0.05% cetylpyridinium chloride (CPC), 0.1% CHX, 0.2% CHX or sterile saline (NaCl) as control. Cell viability, cytotoxicity and apoptosis were assessed at day 0, 3 and 6. Cell viability resulted in being higher in the control group at all time points. At day 0, the CHX 0.2 group showed significantly higher cytotoxicity values compared to CHX 0.1 (30 s), CHX + CPC (30 s, 60 s and 120 s) and control (60 s and 120 s), while no significant differences were identified between CHX + CPC and both CHX 0.1 and NaCl groups. All test mouthwashes were found to induce apoptosis to a lower extent compared to control. Results indicate that 0.2% CHX presented the highest cytotoxic effect. Therefore, its intraoperative use should be carefully considered.

scholarly journals The Oviductal Extracellular Vesicles’ RNA Cargo Regulates the Bovine Embryonic Transcriptome

2020 ◽  
Vol 21 (4) ◽  
pp. 1303 ◽  
Author(s):  
Stefan Bauersachs ◽  
Pascal Mermillod ◽  
Carmen Almiñana
Keyword(s):  
Gene Expression ◽  
Extracellular Vesicles ◽  
Sequencing Analysis ◽  
Rna Seq ◽  
High Throughput Analysis ◽  
Positive Effects ◽  
Early Embryos ◽  
And Control ◽  
The Impact

Oviductal extracellular vesicles (oEVs) are emerging as key players in the gamete/embryo–oviduct interactions that contribute to successful pregnancy. Various positive effects of oEVs on gametes and early embryos have been found in vitro. To determine whether these effects are associated with changes of embryonic gene expression, the transcriptomes of embryos supplemented with bovine fresh (FeEVs) or frozen (FoEVs) oEVs during in vitro culture compared to controls without oEVs were analyzed by low-input RNA sequencing. Analysis of RNA-seq data revealed 221 differentially expressed genes (DEGs) between FoEV treatment and control, 67 DEGs for FeEV and FoEV treatments, and minor differences between FeEV treatment and control (28 DEGs). An integrative analysis of mRNAs and miRNAs contained in oEVs obtained in a previous study with embryonic mRNA alterations pointed to direct effects of oEV cargo on embryos (1) by increasing the concentration of delivered transcripts; (2) by translating delivered mRNAs to proteins that regulate embryonic gene expression; and (3) by oEV-derived miRNAs which downregulate embryonic mRNAs or modify gene expression in other ways. Our study provided the first high-throughput analysis of the embryonic transcriptome regulated by oEVs, increasing our knowledge on the impact of oEVs on the embryo and revealing the oEV RNA components that potentially regulate embryonic development.

scholarly journals IVF outcomes after hysteroscopic metroplasty in patients with T- shaped uterus

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Esra Uyar ◽  
Deniz Usal ◽  
Belgin Selam ◽  
Mehmet Cincik ◽  
Tayfun Bagis
Keyword(s):  
Unexplained Infertility ◽  
Control Group ◽  
Reproductive Outcomes ◽  
Control Groups ◽  
Ivf Outcomes ◽  
Number Of Patients ◽  
Adverse Pregnancy ◽  
And Control ◽  
The Impact

Abstract Background T- shaped uterus may be associated with infertility and adverse pregnancy outcomes. Hysteroscopic metroplasty may improve the reproductivity for these cases. To our knowledge, there is no data in literature about the clinical consequences of in vitro fertilization (IVF) in patients undergoing hysteroscopic metroplasty for T-shaped uterus. The principal objective of the current study is to assess the impact of hysteroscopic metroplasty for T-shaped uterus on the reproductive outcomes of IVF. Methods IVF outcomes of 74 patients who underwent hysteroscopic metroplasty for T- shaped uterus and 148 patients without any uterine abnormalities and with diagnosis of unexplained infertility (control group) were retrospectively analyzed. Results Patients in metroplasty and control groups were comparable with respect to age, BMI, partner’s age and duration of infertility. Number of patients with a history of pregnancy beyond 20 weeks of gestation was significantly lower in the metroplasty group (4.1% vs 18.2%; p < 0.05). Number of previous unsuccessful cycles and percentage of patients with ≥3 unsuccessful IVF cycles (35.1% vs 17.6%; p < 0.05) were significantly higher in the metroplasty group. There were no significant differences in the reproductive outcomes such as the pregnancy rate, clinical pregnancy or live birth rate between the metroplasty and control groups. There were non-significant trends for higher rates of miscarriage (18.8% vs 8%, p > 0.05) and biochemical pregnancy (20.0% vs 10.7%, p > 0.05) in the metroplasty group compared to the control group. Conclusions Reproductive results of the IVF cycles after hysteroscopic correction of T-shaped uterus were comparable to those of the patients without any uterine abnormalities and with diagnosis of unexplained infertility. Hysteroscopic metroplasty may contribute to improved IVF outcomes in patients with T-shaped uterus.

scholarly journals A fluorescent sensor for spatiotemporally resolved endocannabinoid dynamics in vitro and in vivo

2020 ◽  
Author(s):  
Ao Dong ◽  
Kaikai He ◽  
Barna Dudok ◽  
Jordan S Farrell ◽  
Wuqiang Guan ◽  
...  
Keyword(s):  
Membrane Trafficking ◽  
Basolateral Amygdala ◽  
Fluorescent Sensor ◽  
Brain Slices ◽  
High Specificity ◽  
Cultured Neurons ◽  
Spatiotemporal Resolution ◽  
Wide Range

Endocannabinoids (eCBs) are retrograde neuromodulators that play an important role in a wide range of physiological processes; however, the release and in vivo dynamics of eCBs remain largely unknown, due in part to a lack of suitable probes capable of detecting eCBs with sufficient spatiotemporal resolution. Here, we developed a new eCB sensor called GRABeCB2.0. This genetically encoded sensor consists of the human CB1 cannabinoid receptor fused to circular-permutated EGFP, providing cell membrane trafficking, second-resolution kinetics, high specificity for eCBs, and a robust fluorescence response at physiological eCB concentrations. Using the GRABeCB2.0 sensor, we monitored evoked changes in eCB dynamics in both cultured neurons and acute brain slices. Interestingly, in cultured neurons we also observed spontaneous compartmental eCB transients that spanned a distance of approximately 11 μm, suggesting constrained, localized eCB signaling. Moreover, by expressing GRABeCB2.0 in the mouse brain, we readily observed foot shock-elicited and running-triggered eCB transients in the basolateral amygdala and hippocampus, respectively. Lastly, we used GRABeCB2.0 in a mouse seizure model and observed a spreading wave of eCB release that followed a Ca2+ wave through the hippocampus. Thus, GRABeCB2.0 is a robust new probe for measuring the dynamics of eCB release under both physiological and pathological conditions.

scholarly journals Identification of a cono-RFamide from the venom of Conus textile that targets ASIC3 and enhances muscle pain

2017 ◽  
Vol 114 (17) ◽  
pp. E3507-E3515 ◽  
Author(s):  
Catharina Reimers ◽  
Cheng-Han Lee ◽  
Hubert Kalbacher ◽  
Yuemin Tian ◽  
Chih-Hsien Hung ◽  
...  
Keyword(s):  
Ion Channels ◽  
Muscle Pain ◽  
Disulfide Bonds ◽  
High Specificity ◽  
Snail Species ◽  
Cone Snail ◽  
Neuronal Proteins ◽  
Pathological Pain ◽  
Electrophysiological Characterization

Acid-sensing ion channels (ASICs) are proton-gated Na+ channels that are expressed throughout the nervous system. ASICs have been implicated in several neuronal disorders, like ischemic stroke, neuronal inflammation, and pathological pain. Several toxins from venomous animals have been identified that target ASICs with high specificity and potency. These toxins are extremely useful in providing protein pharmacophores and to characterize function and structure of ASICs. Marine cone snails contain a high diversity of toxins in their venom such as conotoxins, which are short polypeptides stabilized by disulfide bonds, and conopeptides, which have no or only one disulfide bond. Whereas conotoxins selectively target specific neuronal proteins, mainly ion channels, the targets of conopeptides are less well known. Here, we perform an in vitro screen of venoms from 18 cone snail species to identify toxins targeting ASICs. We identified a small conopeptide of only four amino acids from the venom of Conus textile that strongly potentiated currents of ASIC3, which has a specific role in the pain pathway. This peptide, RPRFamide, belongs to the subgroup of cono-RFamides. Electrophysiological characterization of isolated dorsal root ganglion (DRG) neurons revealed that RPRFamide increases their excitability. Moreover, injection of the peptide into the gastrocnemius muscle strongly enhanced acid-induced muscle pain in mice that was abolished by genetic inactivation of ASIC3. In summary, we identified a conopeptide that targets the nociceptor-specific ion channel ASIC3.

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