Project description:L-type voltage gated Ca channels play a critical role in E-C coupling in cardiac muscle. alpha1C is associated with beta auxiliary subunits (b1-b4), which regulate cardiac Ca channel gating properties. Here we report a preliminary exploratory study suggesting a novel role of beta4 subunit in heart. We observed that overexpression of beta4 subunit increases the expression of a wide variety of endogenous genes related to antiviral activity. This includes genes in the downstream signalling of RIG-1 pathway such as RIG-1, Irf7 and Ifitm3. The increase expression of these factors may have an antiviral protective role against infection.
Project description:Mesenchymal stromal cells (MSCs) are key components of the tumor microenvironment (TME), influencing leukemia progression through poorly understood mechanisms. Here, the bioelectrical properties of MSCs derived from pediatric acute myeloid leukemia (AML) patients (AML-MSCs) are investigated, identifying a significant depolarization of their resting voltage membrane potential (Vmem, -14.7 mV) compared to healthy MSCs (h-MSCs, -28.5 mV), accompanied by downregulation of Calcium channel, voltage-dependent, L type, alpha 1C subunit1.2 (CaV1.2) L-type calcium channel expression. AML-MSCs display increased spontaneous calcium oscillations, suggesting altered ion homeostasis. Notably, h-MSCs exposed to AML blasts undergo a similar Vmem depolarization (-11.8 mV) and CaV1.2 downregulation, indicating that leukemic cells actively reprogram MSCs. Functionally, Vmem depolarization in h-MSCs promotes a pro-leukemic phenotype, whereas hyperpolarization of AML-MSCs restores a normal behavior. CaV1.2 over-expression by lentiviral vectors in AML-MSCs shifts the Vmem toward hyperpolarization and partially reverses their leukemia-supportive properties, in part through CaV1.2 transfer via tunneling nanotubes. These findings reveal that AML blasts impose a bioelectrical signature on MSCs, modulating ion channel activity to sustain a leukemic niche. Targeting this electrical reprogramming through CaV1.2 restoration represents a potential strategy to re-establish homeostasis in the bone marrow microenvironment.
Project description:Defective ion channel turnover and clearance of damaged proteins are associated with aging and neurodegeneration. The L-type CaV1.2 voltage-gated calcium channel mediate depolarization-induced calcium signals in heart and brain. Here, we determined the interaction surface between the L-type calcium channel CaVβ subunit and actin using cross-linking mass spectrometry and protein-protein docking, and uncovered a role in replenishing damaged CaV1.2 channels. Computational and in vitro mutagenesis identified hotspots in CaVβ that decrease its affinity for actin but not for CaV1.2. Coexpression of an actin-association-deficient CaVβ mutant with the CaV1.2 channel downregulated current amplitudes with a concomitant reduction in the number of functionally available channels. Neither alterations in the single-channel properties nor changes in the total number of channels at the cell surface were found, indicating that current inhibition resulted from a build-up of conduction-defective channels. Our findings established CaVβ–actin interaction as a key player for selective monitoring and clearing corrupted CaV proteins to ensure the maintenance of a functional pool of channels and proper calcium signal transduction. The CaVβ–actin molecular model introduces a potentially druggable protein-protein interface to intervene CaV-mediated signaling processes.
Project description:Defective ion channel turnover and clearance of damaged proteins are associated with aging and neurodegeneration. The L-type CaV1.2 voltage-gated calcium channel mediate depolarization-induced calcium signals in heart and brain. Here, we determined the interaction surface between the L-type calcium channel CaVβ subunit and actin using cross-linking mass spectrometry and protein-protein docking, and uncovered a role in replenishing damaged CaV1.2 channels. Computational and in vitro mutagenesis identified hotspots in CaVβ that decrease its affinity for actin but not for CaV1.2. Coexpression of an actin-association-deficient CaVβ mutant with the CaV1.2 channel downregulated current amplitudes with a concomitant reduction in the number of functionally available channels. Neither alterations in the single-channel properties nor changes in the total number of channels at the cell surface were found, indicating that current inhibition resulted from a build-up of conduction-defective channels. Our findings established CaVβ–actin interaction as a key player for selective monitoring and clearing corrupted CaV proteins to ensure the maintenance of a functional pool of channels and proper calcium signal transduction. The CaVβ–actin molecular model introduces a potentially druggable protein-protein interface to intervene CaV-mediated signaling processes.
Project description:Mitochondrial dysfunction and excessive lipid accumulation in non-adipose tissues have been proposed widely as the roots for comorbidities generated by the growing epidemia of type 2 diabetes mellitus. Mouse models of lipotoxic cardiomyopathy have underlined this detrimental situation, but so far the proteins involved in diabetic patients’s induced mitochondrial dysfunction remain unknown. Apolipoprotein O (ApoO), originally found overexpressed in human diabetics hearts (Lamant et al. JBC 2006), is a candidate that was investigated here at the transcriptome level using H9c2 cardiomyoblasts after stable integration of an expression vector (pTT-ApoO) constitutively expressing ApoO.
Project description:The human HEK293 / 293T and rat cardiomyoblast H9c2 cell lines are commonly employed for microRNA-mRNA interaction studies. Here, I provide microRNA sequencing data obtained from each of these lines to better document which microRNAs are endogenously expressed at high or low levels. Small RNA sequencing profiles were generated from cultured HEK293 and H9c2 cells on Illumina HiSeq 2000 instruments.
Project description:Defective ion channel turnover and clearance of damaged proteins are associated with aging and neurodegeneration. The L-type CaV1.2 voltage-gated calcium channel mediate depolarization-induced calcium signals in heart and brain. Here, we determined the interaction surface between the L-type calcium channel CaVβ subunit and actin using cross-linking mass spectrometry and protein-protein docking, and uncovered a role in replenishing damaged CaV1.2 channels. Computational and in vitro mutagenesis identified hotspots in CaVβ that decrease its affinity for actin but not for CaV1.2. Coexpression of an actin-association-deficient CaVβ mutant with the CaV1.2 channel downregulated current amplitudes with a concomitant reduction in the number of functionally available channels. Neither alterations in the single-channel properties nor changes in the total number of channels at the cell surface were found, indicating that current inhibition resulted from a build-up of conduction-defective channels. Our findings established CaVβ–actin interaction as a key player for selective monitoring and clearing corrupted CaV proteins to ensure the maintenance of a functional pool of channels and proper calcium signal transduction. The CaVβ–actin molecular model introduces a potentially druggable protein-protein interface to intervene CaV-mediated signaling processes.
Project description:Defective ion channel turnover and clearance of damaged proteins are associated with aging and neurodegeneration. The L-type CaV1.2 voltage-gated calcium channel mediate depolarization-induced calcium signals in heart and brain. Here, we determined the interaction surface between the L-type calcium channel CaVβ subunit and actin using cross-linking mass spectrometry and protein-protein docking, and uncovered a role in replenishing damaged CaV1.2 channels. Computational and in vitro mutagenesis identified hotspots in CaVβ that decrease its affinity for actin but not for CaV1.2. Coexpression of an actin-association-deficient CaVβ mutant with the CaV1.2 channel downregulated current amplitudes with a concomitant reduction in the number of functionally available channels. Neither alterations in the single-channel properties nor changes in the total number of channels at the cell surface were found, indicating that current inhibition resulted from a build-up of conduction-defective channels. Our findings established CaVβ–actin interaction as a key player for selective monitoring and clearing corrupted CaV proteins to ensure the maintenance of a functional pool of channels and proper calcium signal transduction. The CaVβ–actin molecular model introduces a potentially druggable protein-protein interface to intervene CaV-mediated signaling processes.