Mosaicism and intronic variants in RB1 gene revealed by next generation sequencing in a cohort of Spanish retinoblastoma patients.

Constitutional variants in the RB1 gene predispose individuals to the development of Retinoblastoma (RB) and the occurrence of second tumors in adulthood. Detection of causal RB1 gene variants is essential to establish the genetic diagnosis and to performing familial studies and counseling. In our cohort of 579 Spanish RB patients, 15% of cases suspected to have a genetic origin remained negative after traditional Sanger sequencing and Multiplex Ligation-dependent Probe Amplification (MLPA) of RB1 gene, likely due to the possibility of mosaicism or non-coding variants.

Cholesterol lowering depletes atherosclerotic lesions of smooth muscle cell-derived fibromyocytes and chondromyocytes.

Drugs that lower plasma apolipoprotein B (ApoB)-containing lipoproteins are central to treating advanced atherosclerosis and provide partial protection against clinical events. Previous research showed that lowering ApoB-containing lipoproteins stops plaque inflammation, but how these drugs affect the heterogeneous population of plaque cells derived from smooth muscle cells (SMCs) is unknown. SMC-derived cells are the main cellular component of atherosclerotic lesions and the source of structural components that determine the size of plaques and their propensity to rupture and trigger thrombosis, the proximate cause of heart attack and stroke.

Acid Sphingomyelinase Deficiency Type B Patient-Derived Liver Organoids Reveals Altered Lysosomal Gene Expression and Lipid Homeostasis.

Acid sphingomyelinase deficiency (ASMD) or Niemann-Pick disease type A (NPA), type B (NPB) and type A/B (NPA/B), is a rare lysosomal storage disease characterized by progressive accumulation of sphingomyelin (SM) in the liver, lungs, bone marrow and, in severe cases, neurons. A disease model was established by generating liver organoids from a NPB patient carrying the p.Arg610del variant in the gene.

Tumor-Derived Pericytes Driven by EGFR Mutations Govern the Vascular and Immune Microenvironment of Gliomas.

The extraordinary plasticity of glioma cells allows them to contribute to different cellular compartments in tumor vessels, reinforcing the vascular architecture. It was recently revealed that targeting glioma-derived pericytes, which represent a big percentage of the mural cell population in aggressive tumors, increases the permeability of the vessels and improves the efficiency of chemotherapy. However, the molecular determinants of this transdifferentiation process have not been elucidated.

The EGFR-TMEM167A-p53 Axis Defines the Aggressiveness of Gliomas.

Despite the high frequency of and genetic alterations in gliomas, little is known about their crosstalk during tumor progression. Here, we described a mutually exclusive distribution between mutations in these two genes. We found that wild-type p53 gliomas are more aggressive than their mutant counterparts, probably because the former accumulate amplifications and/or mutations in and show a stronger activation of this receptor.

Ocoxin Modulates Cancer Stem Cells and M2 Macrophage Polarization in Glioblastoma.

Glioblastoma (GBM) is the most common and devastating primary brain tumor. The presence of cancer stem cells (CSCs) has been linked to their therapy resistance. Molecular and cellular components of the tumor microenvironment also play a fundamental role in the aggressiveness of these tumors.

The Netrin-4/ Neogenin-1 axis promotes neuroblastoma cell survival and migration.

Neogenin-1 (NEO1) is a transmembrane receptor involved in axonal guidance, angiogenesis, neuronal cell migration and cell death, during both embryonic development and adult homeostasis. It has been described as a dependence receptor, because it promotes cell death in the absence of its ligands (Netrin and Repulsive Guidance Molecule (RGM) families) and cell survival when they are present. Although NEO1 and its ligands are involved in tumor progression, their precise role in tumor cell survival and migration remain unclear.

Alternative splicing variants of proinsulin mRNA and the effects of excess proinsulin on cardiac morphogenesis.

Alternative forms of proinsulin mRNA with differential translational capacities and unknown significance are expressed in several developing tissues and in the adult pancreas. In the chick embryo developing heart, we observed low expression of the translationally active transcript of embryonic proinsulin (Pro1B), and predominant expression of the intron 1-unspliced variant, translationally inactive. In the embryonic mouse heart, intron 1-unspliced isoform appeared after E12.

Mitochondrial free [Ca2+] levels and the permeability transition.

Mitochondrial Ca(2+) activates many processes, from mitochondrial metabolism to opening of the permeability transition pore (PTP) and apoptosis. However, there is considerable controversy regarding the free mitochondrial [Ca(2+)] ([Ca(2+)](M)) levels that can be attained during cell activation or even in mitochondrial preparations. Studies using fluorescent dyes (rhod-2 or similar), have reported that phosphate precipitation precludes [Ca(2+)](M) from increasing above 2-3 microM.

Calcium dynamics in bovine adrenal medulla chromaffin cell secretory granules.

The secretory granules constitute one of the less well-known compartments in terms of Ca2+ dynamics. They contain large amounts of total Ca2+, but the free intragranular [Ca2+] ([Ca2+]SG), the mechanisms for Ca2+ uptake and release from the granules and their physiological significance regarding exocytosis are still matters of debate. We used in the present work an aequorin chimera targeted to the granules to investigate [Ca2+]SG homeostasis in bovine adrenal chromaffin cells.

Modulation of Ca(2+) release and Ca(2+) oscillations in HeLa cells and fibroblasts by mitochondrial Ca(2+) uniporter stimulation.

The recent availability of activators of the mitochondrial Ca(2+) uniporter allows direct testing of the influence of mitochondrial Ca(2+) uptake on the overall Ca(2+) homeostasis of the cell. We show here that activation of mitochondrial Ca(2+) uptake by 4,4',4''-(4-propyl-[1H]-pyrazole-1,3,5-triyl)trisphenol (PPT) or kaempferol stimulates histamine-induced Ca(2+) release from the endoplasmic reticulum (ER) and that this effect is enhanced if the mitochondrial Na(+)-Ca(2+) exchanger is simultaneously inhibited with CGP37157. This suggests that both Ca(2+) uptake and release from mitochondria control the ability of local Ca(2+) microdomains to produce feedback inhibition of inositol 1,4,5-trisphosphate receptors (InsP(3)Rs).

The mitochondrial Na+/Ca2+ exchanger plays a key role in the control of cytosolic Ca2+ oscillations.

There is increasing evidence that mitochondria play an important role in the control of cytosolic Ca2+ signaling. We show here that the main mitochondrial Ca2+-exit pathway, the mitochondrial Na+/Ca2+ exchanger, controls the pattern of cytosolic Ca2+ oscillations in non-excitable cells. In HeLa cells, the inhibitor of the mitochondrial Na+/Ca2+ exchanger CGP37157 changed the pattern of the oscillations induced by histamine from a high-frequency irregular one to a lower frequency baseline spike type, surprisingly with little changes in the average Ca2+ values of a large cell population.

Modulation of mitochondrial Ca(2+) uptake by estrogen receptor agonists and antagonists.

Ca(2+) uptake by mitochondria is a key element in the control of cellular Ca(2+) homeostasis and Ca(2+)-dependent phenomena. It has been known for many years that this Ca(2+) uptake is mediated by the mitochondrial Ca(2+) uniporter, a specific Ca(2+) channel of the inner mitochondrial membrane. We have shown previously that this channel is strongly activated by a series of natural phytoestrogenic flavonoids.

Calcium dynamics in catecholamine-containing secretory vesicles.

We have used an aequorin chimera targeted to the membrane of the secretory granules to monitor the free [Ca(2+)] inside them in neurosecretory PC12 cells. More than 95% of the probe was located in a compartment with an homogeneous [Ca(2+)] around 40 microM. Cell stimulation with either ATP, caffeine or high-K(+) depolarization increased cytosolic [Ca(2+)] and decreased secretory granule [Ca(2+)] ([Ca(2+)](SG)).

Direct activation of the mitochondrial calcium uniporter by natural plant flavonoids.

During cell activation, mitochondria play an important role in Ca2+ homoeostasis due to the presence of a fast and specific Ca2+ channel in its inner membrane, the mitochondrial Ca2+ uniporter. This channel allows mitochondria to buffer local cytosolic [Ca2+] changes and controls the intramitochondrial Ca2+ levels, thus modulating a variety of phenomena from respiratory rate to apoptosis. We have described recently that SB202190, an inhibitor of p38 MAPK (mitogen-activated protein kinase), strongly activated the uniporter.