Patient-specific hiPSC-derived cardiomyocytes indicate allelic and contractile imbalance as pathogenic factor in early-stage Hypertrophic Cardiomyopathy.

Hypertrophic Cardiomyopathy (HCM) is often caused by heterozygous mutations in β-myosin heavy chain (MYH7, β-MyHC). In addition to hyper- or hypocontractile effects of HCM-mutations, heterogeneity in contractile function (contractile imbalance) among individual cardiomyocytes was observed in end-stage HCM-myocardium. Contractile imbalance might be induced by burst-like transcription, leading to unequal fractions of mutant versus wildtype mRNA and protein in individual cardiomyocytes (allelic imbalance).

Blood-generating heart-forming organoids recapitulate co-development of the human haematopoietic system and the embryonic heart.

Despite the biomedical importance of haematopoietic stem cells and haematopoietic progenitor cells, their in vitro stabilization in a developmental context has not been achieved due to limited knowledge of signals and markers specifying the multiple haematopoietic waves as well as ethically restricted access to the human embryo. Thus, an in vitro approach resembling aspects of haematopoietic development in the context of neighbouring tissues is of interest. Our established human pluripotent stem cell-derived heart-forming organoids (HFOs) recapitulate aspects of heart, vasculature and foregut co-development.

Functional and structural insights into activation of TRPV2 by weak acids.

Transient receptor potential (TRP) ion channels are involved in the surveillance or regulation of the acid-base balance. Here, we demonstrate that weak carbonic acids, including acetic acid, lactic acid, and CO activate and sensitize TRPV2 through a mechanism requiring permeation through the cell membrane. TRPV2 channels in cell-free inside-out patches maintain weak acid-sensitivity, but protons applied on either side of the membrane do not induce channel activation or sensitization.

Comprehensive assessment of executive functioning following childhood severe traumatic brain injury: clinical utility of the child executive functions battery.

Objectives: To perform a detailed description of executive functioning following moderate-to-severe childhood traumatic brain injury (TBI), and to study demographic and severity factors influencing outcome.

Methods: A convenience sample of children/adolescents aged 7-16 years, referred to a rehabilitation department after a TBI ( = 43), was compared to normative data using a newly developed neuropsychological test battery (Child Executive Functions Battery-CEF-B) and the BRIEF.

Results: Performance in the TBI group was significantly impaired in most of the CEF-B subtests, with moderate to large effect sizes.

Human heart-forming organoids recapitulate early heart and foregut development.

Organoid models of early tissue development have been produced for the intestine, brain, kidney and other organs, but similar approaches for the heart have been lacking. Here we generate complex, highly structured, three-dimensional heart-forming organoids (HFOs) by embedding human pluripotent stem cell aggregates in Matrigel followed by directed cardiac differentiation via biphasic WNT pathway modulation with small molecules. HFOs are composed of a myocardial layer lined by endocardial-like cells and surrounded by septum-transversum-like anlagen; they further contain spatially and molecularly distinct anterior versus posterior foregut endoderm tissues and a vascular network.

Advanced Single-Cell Mapping Reveals that in hESC Cardiomyocytes Contraction Kinetics and Action Potential Are Independent of Myosin Isoform.

Human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) represent an attractive model to investigate CM function and disease mechanisms. One characteristic marker of ventricular specificity of human CMs is expression of the ventricular, slow β-myosin heavy chain (MyHC), as opposed to the atrial, fast α-MyHC. The main aim of this study was to investigate at the single-cell level whether contraction kinetics and electrical activity of hESC-CMs are influenced by the relative expression of α-MyHC versus β-MyHC.

Assessment of everyday executive functioning using the BRIEF in children and adolescents treated for brain tumor.

: Childhood brain tumors (BTs) and their treatment often negatively affect development of executive functions. Previous studies have reported executive functions deficits, particularly through questionnaires of daily life. This study aimed to assess executive functioning in everyday life following pediatric BT, in a larger and more histologically diverse sample than previously, and to study clinical and demographic factors influencing outcome.

Preclinical development of a miR-132 inhibitor for heart failure treatment.

Despite proven efficacy of pharmacotherapies targeting primarily global neurohormonal dysregulation, heart failure (HF) is a growing pandemic with increasing burden. Treatments mechanistically focusing at the cardiomyocyte level are lacking. MicroRNAs (miRNA) are transcriptional regulators and essential drivers of disease progression.

Oxidation of methionine residues activates the high-threshold heat-sensitive ion channel TRPV2.

Thermosensitive transient receptor potential (TRP) ion channels detect changes in ambient temperature to regulate body temperature and temperature-dependent cellular activity. Rodent orthologs of TRP vanilloid 2 (TRPV2) are activated by nonphysiological heat exceeding 50 °C, and human TRPV2 is heat-insensitive. TRPV2 is required for phagocytic activity of macrophages which are rarely exposed to excessive heat, but what activates TRPV2 in vivo remains elusive.

Generation of a CFTR knock-in reporter cell line (MHHi006-A-1) from a human induced pluripotent stem cell line.

CFTR encodes for a chloride ion channel expressed primarily in secretory epithelia in the airways, intestine, liver and other tissues. Mutations in the CFTR gene have been identified in people suffering from Cystic Fibrosis. Here, we established a CFTR knock-in reporter cell line from a human iPSC line (MHHi006-A) using TALEN technology.

Comparing human iPSC-cardiomyocytes versus HEK293T cells unveils disease-causing effects of Brugada mutation A735V of Na1.5 sodium channels.

Loss-of-function mutations of the SCN5A gene encoding for the sodium channel α-subunit Na1.5 result in the autosomal dominant hereditary disease Brugada Syndrome (BrS) with a high risk of sudden cardiac death in the adult. We here engineered human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) carrying the CRISPR/Cas9 introduced BrS-mutation p.

Continuous WNT Control Enables Advanced hPSC Cardiac Processing and Prognostic Surface Marker Identification in Chemically Defined Suspension Culture.

Aiming at clinical translation, robust directed differentiation of human pluripotent stem cells (hPSCs), preferentially in chemically defined conditions, is a key requirement. Here, feasibility of suspension culture based hPSC-cardiomyocyte (hPSC-CM) production in low-cost, xeno-free media compatible with good manufacturing practice standards is shown. Applying stirred tank bioreactor systems at increasing dimensions, our advanced protocol enables routine production of about 1 million hPSC-CMs/mL, yielding ∼1.

Activation of renal ClC-K chloride channels depends on an intact N terminus of their accessory subunit barttin.

ClC-K channels belong to the CLC family of chloride channels and chloride/proton antiporters. They contribute to sodium chloride reabsorption in Henle's loop of the kidney and to potassium secretion into the endolymph by the stria vascularis of the inner ear. Their accessory subunit barttin stabilizes the ClC-K/barttin complex, promotes its insertion into the surface membrane, and turns the pore-forming subunits into a conductive state.

TRPA1 and TRPV1 are required for lidocaine-evoked calcium influx and neuropeptide release but not cytotoxicity in mouse sensory neurons.

Background: Local anaesthetics (LA) reduce neuronal excitability by inhibiting voltage-gated Na+ channels. When applied at high concentrations in the direct vicinity of nerves, LAs can also induce relevant irritation and neurotoxicity via mechanisms involving an increase of intracellular Ca2+. In the present study we explored the role of the Ca2+-permeable ion channels TRPA1 and TRPV1 for lidocaine-induced Ca2+-influx, neuropeptide release and neurotoxicity in mouse sensory neurons.

Reactive metabolites of acetaminophen activate and sensitize the capsaicin receptor TRPV1.

The irritant receptor TRPA1 was suggested to mediate analgesic, antipyretic but also pro-inflammatory effects of the non-opioid analgesic acetaminophen, presumably due to channel activation by the reactive metabolites parabenzoquinone (pBQ) and N-acetyl-parabenzoquinonimine (NAPQI). Here we explored the effects of these metabolites on the capsaicin receptor TRPV1, another redox-sensitive ion channel expressed in sensory neurons. Both pBQ and NAPQI, but not acetaminophen irreversibly activated and sensitized recombinant human and rodent TRPV1 channels expressed in HEK 293 cells.

Inhibition of Voltage-Gated Na+ Channels by Bupivacaine Is Enhanced by the Adjuvants Buprenorphine, Ketamine, and Clonidine.

Background And Objectives: Regional anesthesia includes application of local anesthetics (LAs) into the vicinity of peripheral nerves. Prolongation or improvement of nerve blocks with LAs can be accomplished by coapplication with adjuvants, including buprenorphine, ketamine, and clonidine. While the mechanisms mediating prolonged or improved LA-induced effects by adjuvants are poorly understood, we hypothesized that they are likely to increase LA-induced block of voltage-gated Na channels.

EBIO Does Not Induce Cardiomyogenesis in Human Pluripotent Stem Cells but Modulates Cardiac Subtype Enrichment by Lineage-Selective Survival.

Subtype-specific human cardiomyocytes (CMs) are valuable for basic and applied research. Induction of cardiomyogenesis and enrichment of nodal-like CMs was described for mouse pluripotent stem cells (mPSCs) in response to 1-ethyl-2-benzimidazolinone (EBIO), a chemical modulator of small-/intermediate-conductance Ca-activated potassium channels (SKs 1-4). Investigating EBIO in human pluripotent stem cells (PSCs), we have applied three independent differentiation protocols of low to high cardiomyogenic efficiency.

Lactate is a potent inhibitor of the capsaicin receptor TRPV1.

Tissue ischemia results in an accumulation of lactate and local or systemic lactic acidosis. In nociceptive sensory neurons, lactate was reported to sensitize or activate the transient receptor potential ion channel TRPA1 and acid-sensing ion channels (ASICs). However, it is unclear how lactate modulates the TRPV1 regarded as the main sensor for acidosis in sensory neurons.

H2S and NO cooperatively regulate vascular tone by activating a neuroendocrine HNO-TRPA1-CGRP signalling pathway.

Nitroxyl (HNO) is a redox sibling of nitric oxide (NO) that targets distinct signalling pathways with pharmacological endpoints of high significance in the treatment of heart failure. Beneficial HNO effects depend, in part, on its ability to release calcitonin gene-related peptide (CGRP) through an unidentified mechanism. Here we propose that HNO is generated as a result of the reaction of the two gasotransmitters NO and H2S.

The distinct effects of lipid emulsions used for "lipid resuscitation" on gating and bupivacaine-induced inhibition of the cardiac sodium channel Nav1.5.

Background: Systemic administration of lipid emulsions is an established treatment for local anesthetic intoxication. However, it is unclear by which mechanisms lipids achieve this function. The high cardiac toxicity of the lipophilic local anesthetic bupivacaine probably results from a long-lasting inhibition of the cardiac Na channel Nav1.

The molecular basis for species-specific activation of human TRPA1 protein by protons involves poorly conserved residues within transmembrane domains 5 and 6.

The surveillance of acid-base homeostasis is concerted by diverse mechanisms, including an activation of sensory afferents. Proton-evoked activation of rodent sensory neurons is mainly mediated by the capsaicin receptor TRPV1 and acid-sensing ion channels. In this study, we demonstrate that extracellular acidosis activates and sensitizes the human irritant receptor TRPA1 (hTRPA1).

4-Chloropropofol enhances chloride currents in human hyperekplexic and artificial mutated glycine receptors.

Background: The mammalian neurological disorder hereditary hyperekplexia can be attributed to various mutations of strychnine sensitive glycine receptors. The clinical symptoms of "startle disease" predominantly occur in the newborn leading to convulsive hypertonia and an exaggerated startle response to unexpected mild stimuli. Amongst others, point mutations R271Q and R271L in the α1-subunit of strychnine sensitive glycine receptors show reduced glycine sensitivity and cause the clinical symptoms of hyperekplexia.

Methylglyoxal activates nociceptors through transient receptor potential channel A1 (TRPA1): a possible mechanism of metabolic neuropathies.

Neuropathic pain can develop as an agonizing sequela of diabetes mellitus and chronic uremia. A chemical link between both conditions of altered metabolism is the highly reactive compound methylglyoxal (MG), which accumulates in all cells, in particular neurons, and leaks into plasma as an index of the severity of the disorder. The electrophilic structure of this cytotoxic ketoaldehyde suggests TRPA1, a receptor channel deeply involved in inflammatory and neuropathic pain, as a molecular target.