OCaR1 endows exocytic vesicles with autoregulatory competence by preventing uncontrolled Ca2+ release, exocytosis, and pancreatic tissue damage.

Regulated exocytosis is initiated by increased Ca2+ concentrations in close spatial proximity to secretory granules, which is effectively prevented when the cell is at rest. Here we showed that exocytosis of zymogen granules in acinar cells was driven by Ca2+ directly released from acidic Ca2+ stores including secretory granules through NAADP-activated two-pore channels (TPCs). We identified OCaR1 (encoded by Tmem63a) as an organellar Ca2+ regulator protein integral to the membrane of secretory granules that controlled Ca2+ release via inhibition of TPC1 and TPC2 currents.

Knock-out of dipeptidase CN2 in human proximal tubular cells disrupts dipeptide and amino acid homeostasis and para- and transcellular solute transport.

Aim: Although of potential biomedical relevance, dipeptide metabolism has hardly been studied. We found the dipeptidase carnosinase-2 (CN2) to be abundant in human proximal tubules, which regulate water and solute homeostasis. We therefore hypothesized, that CN2 has a key metabolic role, impacting proximal tubular transport function.

Novel Nongenetic Murine Model of Hyperglycemia and Hyperlipidemia-Associated Aggravated Atherosclerosis.

Objective: Atherosclerosis, the main pathology underlying cardiovascular diseases is accelerated in diabetic patients. Genetic mouse models require breeding efforts which are time-consuming and costly. Our aim was to establish a new nongenetic model of inducible metabolic risk factors that mimics hyperlipidemia, hyperglycemia, or both and allows the detection of phenotypic differences dependent on the metabolic stressor(s).

Development of an AAV9-RNAi-mediated silencing strategy to abrogate TRPM4 expression in the adult heart.

The cation channel transient receptor potential melastatin 4 (TRPM4) is a calcium-activated non-selective cation channel and acts in cardiomyocytes as a negative modulator of the L-type Ca influx. Global deletion of TRPM4 in the mouse led to increased cardiac contractility under β-adrenergic stimulation. Consequently, cardiomyocyte-specific inactivation of the TRPM4 function appears to be a promising strategy to improve cardiac contractility in heart failure patients.

Contribution of NAADP to Glutamate-Evoked Changes in Ca Homeostasis in Mouse Hippocampal Neurons.

Nicotinic acid adenine dinucleotide phosphate (NAADP) is a second messenger that evokes calcium release from intracellular organelles by the engagement of calcium release channels, including members of the Transient Receptor Potential (TRP) family, such as TRPML1, the (structurally) related Two Pore Channel type 1 (TPC1) and TPC2 channels as well as Ryanodine Receptors type 1 (RYR1; Guse, 2012). NAADP evokes calcium release from acidic calcium stores of many cell types (Guse, 2012), and NAADP-sensitive Ca stores have been described in hippocampal neurons of the rat (Bak et al., 1999; McGuinness et al.

Saraf-dependent activation of mTORC1 regulates cardiac growth.

Pathological cardiac hypertrophy is an independent risk for heart failure (HF) and sudden death. Deciphering signaling pathways regulating intracellular Ca homeostasis that control adaptive and pathological cardiac growth may enable identification of novel therapeutic targets. The objective of the present study is to determine the role of the store-operated calcium entry-associated regulatory factor (Saraf), encoded by the Tmem66 gene, on cardiac growth control in vitro and in vivo.

TRPC channels are not required for graded persistent activity in entorhinal cortex neurons.

Adaptive behavior requires the transient storage of information beyond the physical presence of external stimuli. This short-lasting form of memory involves sustained ("persistent") neuronal firing which may be generated by cell-autonomous biophysical properties of neurons or/and neural circuit dynamics. A number of studies from brain slices reports intrinsically generated persistent firing in cortical excitatory neurons following suprathreshold depolarization by intracellular current injection.

Endovascular Therapy for Erectile Dysfunction-Who Benefits Most? Insights From a Single-Center Experience.

Purpose: To report the 1-year outcomes of a single-center, all-comers registry aimed to assess effectiveness and safety of endovascular revascularization for atherosclerotic erectile dysfunction (ED) in an unselected patient cohort.

Materials And Methods: Between April 2016 and October 2017, 50 consecutive patients (mean age 59.6±10.

Methylglyoxal evokes acute Ca transients in distinct cell types and increases agonist-evoked Ca entry in endothelial cells via CRAC channels.

Methylglyoxal (MG) is a by-product of glucose metabolism and its accumulation has been linked to the development of diabetic complications such as retinopathy and nephropathy by affecting multiple signalling pathways. However, its influence on the intracellular Ca homeostasis and particularly Ca entry, which has been reported to be mediated via TRPA1 channels in DRG neurons, has not been studied in much detail in other cell types. In this study, we report the consequences of acute and long-term MG application on intracellular Ca levels in endothelial cells.

Compensatory mechanisms for methylglyoxal detoxification in experimental & clinical diabetes.

Objectives: The deficit of Glyoxalase I (Glo1) and the subsequent increase in methylglyoxal (MG) has been reported to be one the five mechanisms by which hyperglycemia causes diabetic late complications. Aldo-keto reductases (AKR) have been shown to metabolize MG; however, the relative contribution of this superfamily to the detoxification of MG in vivo, particularly within the diabetic state, remains unknown.

Methods: CRISPR/Cas9-mediated genome editing was used to generate a Glo1 knock-out (Glo1) mouse line.

Deletion of Orai2 augments endogenous CRAC currents and degranulation in mast cells leading to enhanced anaphylaxis.

All three members of the Orai family of cation channels-Orai1, Orai2 and Orai3-are integral membrane proteins that can form store-operated Ca channels resembling endogenous calcium release-activated channels (CRAC) in many aspects. Loss of function studies in human and murine models revealed many functions of Orai1 proteins not only for Ca homeostasis, but also for cellular and systemic functions in many cell types. By contrast, the knowledge regarding the contribution of Orai2 and Orai3 proteins in these processes is sparse.

TRPC proteins contribute to development of diabetic retinopathy and regulate glyoxalase 1 activity and methylglyoxal accumulation.

Objective: Diabetic retinopathy (DR) is induced by an accumulation of reactive metabolites such as ROS, RNS, and RCS species, which were reported to modulate the activity of cation channels of the TRPC family. In this study, we use Trpc1/4/5/6 compound knockout mice to analyze the contribution of these TRPC proteins to diabetic retinopathy.

Methods: We used Nanostring- and qPCR-based analysis to determine mRNA levels of TRPC channels in control and diabetic retinae and retinal cell types.

Loss of Glyoxalase 1 Induces Compensatory Mechanism to Achieve Dicarbonyl Detoxification in Mammalian Schwann Cells.

The glyoxalase system is a highly specific enzyme system existing in all mammalian cells that is responsible for the detoxification of dicarbonyl species, primarily methylglyoxal (MG). It has been implicated to play an essential role in preventing the increased formation of advanced glycation end products under certain pathological conditions. We have established the first glyoxalase 1 knock-out model (GLO1) in mammalian Schwann cells using the CRISPR/Cas9 technique to investigate compensatory mechanisms.

Platelet-derived nucleotides promote tumor-cell transendothelial migration and metastasis via P2Y2 receptor.

Tumor cells can activate platelets, which in turn facilitate tumor cell survival and dissemination. The exact mechanisms by which platelets promote metastasis have remained unclear. Here, we show that adenine nucleotides released from tumor cell-activated platelets induce opening of the endothelial barrier to allow transendothelial migration of tumor cells and thereby promote cancer cell extravasation.