Human induced pluripotent stem cells (hiPSCs) are an invaluable tool to study molecular mechanisms on a human background. Culturing stem cells at an oxygen level different from their microenvironmental niche impacts their viability. To understand this mechanistically, dermal skin fibroblasts of 52 probands were reprogrammed into hiPSCs, followed by either hyperoxic (20 % O) or physioxic (5 % O) culture and proteomic profiling.
View Article and Find Full Text PDFBackground: Cardiac hypertrophy is characterized by remodeling of the myocardium, which involves alterations in the ECM (extracellular matrix) and cardiomyocyte structure. These alterations critically contribute to impaired contractility and relaxation, ultimately leading to heart failure. Emerging evidence implicates that extracellular signaling molecules are critically involved in the pathogenesis of cardiac hypertrophy and remodeling.
View Article and Find Full Text PDFNeutrophils are not only involved in immune defense against infection but also contribute to the exacerbation of tissue damage after ischemia and reperfusion. We have previously shown that genetic ablation of regulatory Gα proteins in mice has both protective and deleterious effects on myocardial ischemia reperfusion injury (mIRI), depending on which isoform is deleted. To deepen and analyze these findings in more detail the contribution of Gα proteins in resident cardiac vs circulating blood cells for mIRI was first studied in bone marrow chimeras.
View Article and Find Full Text PDFAlterations in the function of K channels such as the voltage- and Ca-activated K channel of large conductance (BK) reportedly promote breast cancer (BC) development and progression. Underlying molecular mechanisms remain, however, elusive. Here, we provide electrophysiological evidence for a BK splice variant localized to the inner mitochondrial membrane of murine and human BC cells (mitoBK).
View Article and Find Full Text PDFVarious disorders are accompanied by histamine-independent itching, which is often resistant to the currently available therapies. Here, it is reported that the pharmacological activation of Slack (Kcnt1, K1.1), a potassium channel highly expressed in itch-sensitive sensory neurons, has therapeutic potential for the treatment of itching.
View Article and Find Full Text PDFAutism spectrum disorder is discussed in the context of altered neural oscillations and imbalanced cortical excitation-inhibition of cortical origin. We studied here whether developmental changes in peripheral auditory processing, while preserving basic hearing function, lead to altered cortical oscillations. Local field potentials (LFPs) were recorded from auditory, visual, and prefrontal cortices and the hippocampus of Bdnf KO mice.
View Article and Find Full Text PDFMutations of large conductance Ca- and voltage-activated K channels (BK) are associated with cognitive impairment. Here we report that CA1 pyramidal neuron-specific conditional BK knock-out (cKO) mice display normal locomotor and anxiety behavior. They do, however, exhibit impaired memory acquisition and retrieval in the Morris Water Maze (MWM) when compared to littermate controls (CTRL).
View Article and Find Full Text PDFMutations of the Na-activated K channel Slack (KCNT1) are associated with terrible epilepsy syndromes that already begin in infancy. Here we report increased severity of acute kainic acid-induced seizures in adult and juvenile Slack knockout mice (Slack) in vivo. Fittingly, we find exacerbation of cell death following kainic acid exposure in organotypic hippocampal slices as well as dissociated hippocampal cultures from Slack in vitro.
View Article and Find Full Text PDF2023 marks the 30th anniversary of the discovery of single-domain antibody fragments in camelids, better known as nanobodies. This was the starting point for their tremendous success story in biomedicine. Here we highlight recent advances in the development of nanobodies for the detection of neutralizing SARS-CoV-2 antibodies, as biosensors for monitoring extracellular metabolites and as tracer molecules for non-invasive imaging of immune cells.
View Article and Find Full Text PDFBackground: Pathophysiologic platelet activation leads to thrombo-occlusive diseases such as myocardial infarction or ischemic stroke. Niemann-Pick C1 protein (NPC1) is involved in the regulation of lysosomal lipid trafficking and calcium ion (Ca) signaling, and its genetic mutation causes a lysosomal storage disorder. Lipids and Ca are key players in the complex orchestration of platelet activation.
View Article and Find Full Text PDFIon channels are non-conventional, druggable oncological targets. The intermediate-conductance calcium-dependent potassium channel (K3.1) is highly expressed in the plasma membrane and in the inner mitochondrial membrane (mitoK3.
View Article and Find Full Text PDFCa-activated K channels of intermediate conductance (IK) are frequently overexpressed in breast cancer (BC) cells, while IK channel depletion reduces BC cell proliferation and tumorigenesis. This raises the question, of whether and mechanistically how IK activity interferes with the metabolic activity and energy consumption rates, which are fundamental for rapidly growing cells. Using BC cells obtained from MMTV-PyMT tumor-bearing mice, we show that both, glycolysis and mitochondrial ATP-production are reduced in cells derived from IK-deficient breast tumors.
View Article and Find Full Text PDFUnlabelled: Women after mastectomy may decide to either have a breast reconstruction or use an external breast prosthesis.
Aim: The aim of the presented research was to evaluate the influence of external breast prosthesis on postural stability in women after mastectomy.
Methods And Procedures: In the study 52 women after unilateral mastectomy took part.
Ion and analyte changes in the tumor microenvironment (TME) alter the metabolic activity of cancer cells, promote tumor cell growth, and impair anti-tumor immunity. Consequently, accurate determination and visualization of extracellular changes of analytes in real time is desired. In this study, we genetically combined FRET-based biosensors with nanobodies (Nbs) to specifically visualize and monitor extracellular changes in K, pH, and glucose on cell surfaces.
View Article and Find Full Text PDFThe transient receptor potential (TRP) ankyrin type 1 (TRPA1) channel is highly expressed in a subset of sensory neurons where it acts as an essential detector of painful stimuli. However, the mechanisms that control the activity of sensory neurons upon TRPA1 activation remain poorly understood. Here, using in situ hybridization and immunostaining, we found TRPA1 to be extensively co-localized with the potassium channel Slack (K1.
View Article and Find Full Text PDFVascular smooth muscle cells (VSMCs) can switch from their contractile state to a synthetic phenotype resulting in high migratory and proliferative capacity and driving atherosclerotic lesion formation. The cysteine-rich LIM-only protein 4 (CRP4) reportedly modulates VSM-like transcriptional signatures, which are perturbed in VSMCs undergoing phenotypic switching. Thus, we hypothesized that CRP4 contributes to adverse VSMC behaviours and thereby to atherogenesis in vivo.
View Article and Find Full Text PDFBackground: Slick, a sodium-activated potassium channel, has been recently identified in somatosensory pathways, but its functional role is poorly understood. The authors of this study hypothesized that Slick is involved in processing sensations of pain and itch.
Methods: Immunostaining, in situ hybridization, Western blot, and real-time quantitative reverse transcription polymerase chain reaction were used to investigate the expression of Slick in dorsal root ganglia and the spinal cord.
The key auditory signature that may associate peripheral hearing with central auditory cognitive defects remains elusive. Suggesting the involvement of stress receptors, we here deleted the mineralocorticoid and glucocorticoid receptors ( and ) using a CaMKIIα-based tamoxifen-inducible Cre/ approach to generate mice with single or double deletion of central but not cochlear MR and GR. Hearing thresholds of MRGR conditional knockouts () were unchanged, whereas auditory nerve fiber () responses were larger and faster and auditory steady state responses were improved.
View Article and Find Full Text PDFNeutrophils are the most numerous cells in the leukocyte population and essential for innate immunity. To limit their effector functions, neutrophils are able to modulate glycolysis and other cellular metabolic pathways. These metabolic pathways are essential not only for energy usage, but also for specialized effector actions, such as the production of reactive oxygen species (ROS), chemotaxis, phagocytosis, degranulation, and the formation of neutrophil extracellular traps (NETs).
View Article and Find Full Text PDFCancer represents a leading cause of death worldwide. Hence, a better understanding of the molecular mechanisms causing and propelling the disease is of utmost importance. Several cancer entities are associated with altered K channel expression which is frequently decisive for malignancy and disease outcome.
View Article and Find Full Text PDFWe have recently demonstrated that the activity of hexokinase 2 is dependent on the intracellular potassium ion (K) concentration ([K]). To analyze the K dependency of the cell metabolism in cell populations, we used an extracellular flux analyzer to assess oxygen consumption and acidification rates as well-established measures of oxidative- and glycolytic metabolic activities. This protocol describes in detail how a potential K sensitivity of the cell metabolism can be elucidated by extracellular flux analysis.
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