5 research outputs found
Hepatitis B virus PreS2-mutant large surface antigen activates store-operated calcium entry and promotes chromosome instability
[[abstract]]Hepatitis B virus (HBV) is a driver of hepatocellular carcinoma, and two viral products, X and large surface antigen (LHBS), are viral oncoproteins. During chronic viral infection, immune-escape mutants on the preS2 region of LHBS (preS2-LHBS) are gain-of-function mutations that are linked to preneoplastic ground glass hepatocytes (GGHs) and early disease onset of hepatocellular carcinoma. Here, we show that preS2-LHBS provoked calcium release from the endoplasmic reticulum (ER) and triggered stored-operated calcium entry (SOCE). The activation of SOCE increased ER and plasma membrane (PM) connections, which was linked by ER- resident stromal interaction molecule-1 (STIM1) protein and PM-resident calcium release- activated calcium modulator 1 (Orai1). Persistent activation of SOCE induced centrosome overduplication, aberrant multipolar division, chromosome aneuploidy, anchorage-independent growth, and xenograft tumorigenesis in hepatocytes expressing preS2- LHBS. Chemical inhibitions of SOCE machinery and silencing of STIM1 significantly reduced centrosome numbers, multipolar division, and xenograft tumorigenesis induced by preS2-LHBS. These results provide the first mechanistic link between calcium homeostasis and chromosome instability in hepatocytes carrying preS2-LHBS. Therefore, persistent activation of SOCE represents a novel pathological mechanism in HBV-mediated hepatocarcinogenesis
Live Cell Imaging in Microfluidic Device Proves Resistance to Oxygen/Glucose Deprivation in Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes
Analyses of cellular responses to
fast oxygen dynamics are challenging
and require ad hoc technological solutions, especially when decoupling
from liquid media composition is required. In this work, we present
a microfluidic device specifically designed for culture analyses with
high resolution and magnification objectives, providing full optical
access to the cell culture chamber. This feature allows fluorescence-based
assays, photoactivated surface chemistry, and live cell imaging under
tightly controlled pO<sub>2</sub> environments. The device has a simple
design, accommodates three independent cell cultures, and can be employed
by users with basic cell culture training in studies requiring fast
oxygen dynamics, defined media composition, and in-line data acquisition
with optical molecular probes. We apply this technology to produce
an oxygen/glucose deprived (OGD) environment and analyze cell mortality
in murine and human cardiac cultures. Neonatal rat ventricular cardiomyocytes
show an OGD time-dependent sensitivity, resulting in a robust and
reproducible 66 ± 5% death rate after 3 h of stress. Applying
an equivalent stress to human induced pluripotent stem cell-derived
cardiomyocytes (hiPS-CMs) provides direct experimental evidence for
fetal-like OGD-resistant phenotype. Investigation on the nature of
such phenotype exposed large glycogen deposits. We propose a culture
strategy aimed at depleting these intracellular energy stores and
concurrently activate positive regulation of aerobic metabolic molecular
markers. The observed process, however, is not sufficient to induce
an OGD-sensitive phenotype in hiPS-CMs, highlighting defective development
of mature aerobic metabolism <i>in vitro</i>
Live Cell Imaging in Microfluidic Device Proves Resistance to Oxygen/Glucose Deprivation in Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes
Analyses of cellular responses to
fast oxygen dynamics are challenging
and require ad hoc technological solutions, especially when decoupling
from liquid media composition is required. In this work, we present
a microfluidic device specifically designed for culture analyses with
high resolution and magnification objectives, providing full optical
access to the cell culture chamber. This feature allows fluorescence-based
assays, photoactivated surface chemistry, and live cell imaging under
tightly controlled pO<sub>2</sub> environments. The device has a simple
design, accommodates three independent cell cultures, and can be employed
by users with basic cell culture training in studies requiring fast
oxygen dynamics, defined media composition, and in-line data acquisition
with optical molecular probes. We apply this technology to produce
an oxygen/glucose deprived (OGD) environment and analyze cell mortality
in murine and human cardiac cultures. Neonatal rat ventricular cardiomyocytes
show an OGD time-dependent sensitivity, resulting in a robust and
reproducible 66 ± 5% death rate after 3 h of stress. Applying
an equivalent stress to human induced pluripotent stem cell-derived
cardiomyocytes (hiPS-CMs) provides direct experimental evidence for
fetal-like OGD-resistant phenotype. Investigation on the nature of
such phenotype exposed large glycogen deposits. We propose a culture
strategy aimed at depleting these intracellular energy stores and
concurrently activate positive regulation of aerobic metabolic molecular
markers. The observed process, however, is not sufficient to induce
an OGD-sensitive phenotype in hiPS-CMs, highlighting defective development
of mature aerobic metabolism <i>in vitro</i>
Live Cell Imaging in Microfluidic Device Proves Resistance to Oxygen/Glucose Deprivation in Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes
Analyses of cellular responses to
fast oxygen dynamics are challenging
and require ad hoc technological solutions, especially when decoupling
from liquid media composition is required. In this work, we present
a microfluidic device specifically designed for culture analyses with
high resolution and magnification objectives, providing full optical
access to the cell culture chamber. This feature allows fluorescence-based
assays, photoactivated surface chemistry, and live cell imaging under
tightly controlled pO<sub>2</sub> environments. The device has a simple
design, accommodates three independent cell cultures, and can be employed
by users with basic cell culture training in studies requiring fast
oxygen dynamics, defined media composition, and in-line data acquisition
with optical molecular probes. We apply this technology to produce
an oxygen/glucose deprived (OGD) environment and analyze cell mortality
in murine and human cardiac cultures. Neonatal rat ventricular cardiomyocytes
show an OGD time-dependent sensitivity, resulting in a robust and
reproducible 66 ± 5% death rate after 3 h of stress. Applying
an equivalent stress to human induced pluripotent stem cell-derived
cardiomyocytes (hiPS-CMs) provides direct experimental evidence for
fetal-like OGD-resistant phenotype. Investigation on the nature of
such phenotype exposed large glycogen deposits. We propose a culture
strategy aimed at depleting these intracellular energy stores and
concurrently activate positive regulation of aerobic metabolic molecular
markers. The observed process, however, is not sufficient to induce
an OGD-sensitive phenotype in hiPS-CMs, highlighting defective development
of mature aerobic metabolism <i>in vitro</i>
Cinnamic Anilides as New Mitochondrial Permeability Transition Pore Inhibitors Endowed with Ischemia-Reperfusion Injury Protective Effect in Vivo
In
this account, we report the development of a series of substituted
cinnamic anilides that represents a novel class of mitochondrial permeability
transition pore (mPTP) inhibitors. Initial class expansion led to
the establishment of the basic structural requirements for activity
and to the identification of derivatives with inhibitory potency higher
than that of the standard inhibitor cyclosporine-A (CsA). These compounds
can inhibit mPTP opening in response to several stimuli including
calcium overload, oxidative stress, and thiol cross-linkers. The activity
of the cinnamic anilide mPTP inhibitors turned out to be additive
with that of CsA, suggesting for these inhibitors a molecular target
different from cyclophylin-D. In vitro and in vivo data are presented
for (<i>E</i>)-3-(4-fluoro-3-hydroxy-phenyl)-<i>N</i>-naphthalen-1-yl-acrylamide <b>22</b>, one of the most interesting
compounds in this series, able to attenuate opening of the mPTP and
limit reperfusion injury in a rabbit model of acute myocardial infarction