Using C. elegans as a model for neurodegenerative diseases: Methodology and evaluation.

Caenorhabditis elegans is a nematode that has been used as an animal model for almost 50years. It has primitive and simple tissues and organs, making it an ideal model for studying neurological pathways involved in neurodegenerative diseases like Alzheimer's disease (AD) and Parkinson's disease (PD). C.

Enhanced Mitochondria-SR Tethering Triggers Adaptive Cardiac Muscle Remodeling.

Background: Cardiac contractile function requires high energy from mitochondria, and Ca from the sarcoplasmic reticulum (SR). Via local Ca transfer at close mitochondria-SR contacts, cardiac excitation feedforward regulates mitochondrial ATP production to match surges in demand (excitation-bioenergetics coupling). However, pathological stresses may cause mitochondrial Ca overload, excessive reactive oxygen species production and permeability transition, risking homeostatic collapse and myocyte loss.

SLC25A46 promotes mitochondrial fission and mediates resistance to lipotoxic stress in INS-1E insulin-secreting cells.

Glucose sensing in pancreatic β-cells depends on oxidative phosphorylation and mitochondria-derived signals that promote insulin secretion. Using mass spectrometry-based phosphoproteomics to search for downstream effectors of glucose-dependent signal transduction in INS-1E insulinoma cells, we identified the outer mitochondrial membrane protein SLC25A46. Under resting glucose concentrations, SLC25A46 was phosphorylated on a pair of threonine residues (T44/T45) and was dephosphorylated in response to glucose-induced Ca2+ signals.

The role of mitochondria in metabolic disease: a special emphasis on heart dysfunction.

Metabolic diseases (MetDs) embrace a series of pathologies characterized by abnormal body glucose usage. The known diseases included in this group are metabolic syndrome, prediabetes and diabetes mellitus types 1 and 2. All of them are chronic pathologies that present metabolic disturbances and are classified as multi-organ diseases.

Mitochondrial Ca concentrations in live cells: quantification methods and discrepancies.

Intracellular Ca signaling controls numerous cellular functions. Mitochondria respond to cytosolic Ca changes by adapting mitochondrial functions and, in some cell types, shaping the spatiotemporal properties of the cytosolic Ca signal. Numerous methods have been developed to specifically and quantitatively measure the mitochondrial-free Ca concentrations ([Ca ] ), but there are still significant discrepancies in the calculated absolute values of [Ca ] in stimulated live cells.

SR-mitochondria communication in adult cardiomyocytes: A close relationship where the Ca has a lot to say.

In adult cardiomyocytes, T-tubules, junctional sarcoplasmic reticulum (jSR), and mitochondria juxtapose each other and form a unique and highly repetitive functional structure along the cell. The close apposition between jSR and mitochondria creates high Ca microdomains at the contact sites, increasing the efficiency of the excitation-contraction-bioenergetics coupling, where the Ca transfer from SR to mitochondria plays a critical role. The SR-mitochondria contacts are established through protein tethers, with mitofusin 2 the most studied SR-mitochondrial "bridge", albeit controversial.

Spatial Separation of Mitochondrial Calcium Uptake and Extrusion for Energy-Efficient Mitochondrial Calcium Signaling in the Heart.

Mitochondrial Ca elevations enhance ATP production, but uptake must be balanced by efflux to avoid overload. Uptake is mediated by the mitochondrial Ca uniporter channel complex (MCUC), and extrusion is controlled largely by the Na/Ca exchanger (NCLX), both driven electrogenically by the inner membrane potential (ΔΨ). MCUC forms hotspots at the cardiac mitochondria-junctional SR (jSR) association to locally receive Ca signals; however, the distribution of NCLX is unknown.

Increased mitochondrial nanotunneling activity, induced by calcium imbalance, affects intermitochondrial matrix exchanges.

Exchanges of matrix contents are essential to the maintenance of mitochondria. Cardiac mitochondrial exchange matrix content in two ways: by direct contact with neighboring mitochondria and over longer distances. The latter mode is supported by thin tubular protrusions, called nanotunnels, that contact other mitochondria at relatively long distances.

Strategic Positioning and Biased Activity of the Mitochondrial Calcium Uniporter in Cardiac Muscle.

Control of myocardial energetics by Ca signal propagation to the mitochondrial matrix includes local Ca delivery from sarcoplasmic reticulum (SR) ryanodine receptors (RyR2) to the inner mitochondrial membrane (IMM) Ca uniporter (mtCU). mtCU activity in cardiac mitochondria is relatively low, whereas the IMM surface is large, due to extensive cristae folding. Hence, stochastically distributed mtCU may not suffice to support local Ca transfer.

Predicting outcome in 259 fetuses with agenesis of ductus venosus - a multicenter experience and systematic review of the literature (.).

Objective: To evaluate prenatal predictors of postnatal survival in fetuses with agenesis of ductus venosus (ADV).

Methods: This retrospective study reviewed our experience and the literature between 1991 and 2015. Prenatal findings were evaluated and perinatal morbidity and mortality was documented.

Effects of long-term feeding of the polyphenols resveratrol and kaempferol in obese mice.

The effect of the intake of antioxidant polyphenols such as resveratrol and others on survival and different parameters of life quality has been a matter of debate in the last years. We have studied here the effects of the polyphenols resveratrol and kaempferol added to the diet in a murine model undergoing long-term hypercaloric diet. Using 50 mice for each condition, we have monitored weight, survival, biochemical parameters such as blood glucose, insulin, cholesterol, triglycerides and aspartate aminotransferase, neuromuscular coordination measured with the rotarod test and morphological aspect of stained sections of liver and heart histological samples.

Dynamics of mitochondrial Ca2+ uptake in MICU1-knockdown cells.

MICU1 (Ca2+ uptake protein 1, mitochondrial) is an important regulator of the MCU (Ca2+ uniporter protein, mitochondrial) that has been shown recently to act as a gatekeeper of the MCU at low [Ca2+]c (cytosolic [Ca2+]). In the present study we have investigated in detail the dynamics of MCU activity after shRNA-knockdown of MICU1 and we have found several new interesting properties. In MICU1-knockdown cells, the rate of mitochondrial Ca2+ uptake was largely increased at a low [Ca2+]c (<2 μM), but it was decreased at a high [Ca2+]c (>4 μM).

Ca2+ homeostasis in the endoplasmic reticulum measured with a new low-Ca2+-affinity targeted aequorin.

We use here a new very low-Ca(2+)-affinity targeted aequorin to measure the [Ca(2+)] in the endoplasmic reticulum ([Ca(2+)]ER). The new aequorin chimera has the right Ca(2+)-affinity to make long-lasting measurements of [Ca(2+)]ER in the millimolar range. Moreover, previous Ca(2+)-depletion of the ER is no longer required.

Silencing of the Charcot-Marie-Tooth disease-associated gene GDAP1 induces abnormal mitochondrial distribution and affects Ca2+ homeostasis by reducing store-operated Ca2+ entry.

GDAP1 is an outer mitochondrial membrane protein that acts as a regulator of mitochondrial dynamics. Mutations of the GDAP1 gene cause Charcot-Marie-Tooth (CMT) neuropathy. We show that GDAP1 interacts with the vesicle-organelle trafficking proteins RAB6B and caytaxin, which suggests that GDAP1 may participate in the mitochondrial movement within the cell.

Dynamics of mitochondrial [Ca(2+)] measured with the low-Ca(2+)-affinity dye rhod-5N.

Available methods to measure mitochondrial [Ca(2+)] ([Ca(2+)](M)) include both targeted proteins and fluorescent dyes. Targeted proteins usually report much higher [Ca(2+)](M) values than fluorescent dyes, up to two orders of magnitude. However, we show here that the low-Ca(2+)-affinity dye rhod-5N provides [Ca(2+)](M) values similar to those reported by targeted aequorin, suggesting that the discrepancies are mainly due to the higher Ca(2+)-affinity of the fluorescent dyes used.

Monitoring mitochondrial [Ca(2+)] dynamics with rhod-2, ratiometric pericam and aequorin.

The dynamics of mitochondrial [Ca(2+)] ([Ca(2+)](M)) plays a key role in a variety of cellular processes. The most important methods available to monitor [Ca(2+)](M) are fluorescent dyes such as rhod-2 and specifically targeted proteins such as aequorin and pericam. However, significant discrepancies, both quantitative and qualitative, exist in the literature between the results obtained with different methods.

The dynamics of mitochondrial Ca2+ fluxes.

We have investigated the kinetics of mitochondrial Ca(2+) influx and efflux and their dependence on cytosolic [Ca(2+)] and [Na(+)] using low-Ca(2+)-affinity aequorin. The rate of Ca(2+) release from mitochondria increased linearly with mitochondrial [Ca(2+)] ([Ca(2+)](M)). Na(+)-dependent Ca(2+) release was predominant al low [Ca(2+)](M) but saturated at [Ca(2+)](M) around 400muM, while Na(+)-independent Ca(2+) release was very slow at [Ca(2+)](M) below 200muM, and then increased at higher [Ca(2+)](M), perhaps through the opening of a new pathway.

Discordant lower urinary tract obstruction in early twin gestations: management and outcome.

Objective: To report our experience with the management of twin pregnancies discordant for lower urinary tract obstruction.

Methods: Cases of twin pregnancies discordant for lower urinary tract obstruction were identified from our fetal medicine database. Information on ultrasonographic findings, antenatal course, pregnancy complications, and perinatal outcome was obtained by reviewing medical records or contacting the referring obstetricians.