Ischemic preconditioning induces lateralization and dephosphorylation of Connexin 43 (Cx43). However, the Cx43 protein that remains at intercalated disks may be phosphorylated by casein kinase 1 (CK1) and protein kinase C (PKC), and both kinases provide cardioprotection from further ischemic injury. Here we explore the channel characteristics of a Cx43 mutant mimicking preconditioning by CK1 and PKC phosphorylation. Whole-cell patch-clamp recordings were performed in cells expressing the mutant Cx43pc (S325,328,330,368D, S365A-Cx43), and the connexin electrical behavior was analyzed at the single channel and macroscopic level. Cx43pc hemichannels opened readily, whereas gap junctions channels displayed amplitudes between the wild-type and CK1 phosphorylated forms, and weaker voltage gating than either counterpart. Ischemic preconditioning and the ensuing phosphorylation of Cx43 by PKC may render junctional channels insensitive to transjunctional voltages, allowing the preservation of intercellular communication in ischemic conditions.

Aging is a complex, multifaceted process that affects all organisms, characterized by functional decline and increased risk of death. Although the molecular and cellular basis of aging has been extensively studied, the roles of bioelectricity, biochemical gradients, and biomechanical gradients in this process remain less understood. This review investigates the current knowledge concerning these factors and their influence on aging at molecular, cellular, and whole organism levels. I examine the connection between steady-state membrane voltage (Vmem) and mitotic division, the relationship between mitochondrial membrane potential and aging, the role of epigenetic modifications in regulating gene expression, and the deliberate manipulation of bioelectric gradients to achieve desired outcomes in aging. This review emphasizes the need for further research to better comprehend the role of bioelectricity and chemical gradients in aging, and to identify potential targets for interventions to delay or alleviate the effects of aging.

Bioelectricity has been studied since the 18th century in every branch of the tree of life. Bioelectricity is involved in cell growth, proliferation, and behavior, which at a tissue-scale level translates in dramatic tissue rearrangements during embryology and somatic development. Although ion fluxes can be measured in single cells, it is not unanimous that a single cell may create and sustain different bioelectrical states within itself by means of electrochemical nonequilibrium phenomena. We address this possibility, with a focus on the pollen tube as a biological model. Pollen tubes are the subject of intense research given its unique properties, evolutionary streamlined to very fast apical growth and sensitivity to external cues that affect chemotropic responses. Pollen tube's functions rely on conspicuous tip-focused ions dynamics, involving the formation of steep ion gradients, with ion concentration differences over an order of magnitude when compared with the shank cytosol. These gradients are thought to be based on the spatial segregation of ion transporters, channels, and pumps along the cell, creating distinct electrochemical environments at the tip and the shank. But how polarity is generated and maintained is still a matter of debate. In the past we hypothesized that opposing electrochemical forces of depolarization at the tip and hyperpolarization in the shank could create a membrane potential gradient spanning from the tip to the shank that would be part of feedback mechanisms essential to cell polarity in these and likely other cell types. In this study, we review the latest progress on understanding apical growth from the perspective of bioelectricity-driven morphogenesis.

The ability to generate distinct spatiotemporal patterns of cytosolic calcium concentration (Ca 2+ cyt ) is a fundamental property of eukaryotic cells and underlies responses to external stimuli as well as directing downstream processes involved in morphogenesis, growth, and even developmental fate. In this review, we consider a number of well-studied and less well-studied photosynthetic plant and algal systems from the point of view of the different Ca 2+ channel types that underlie spatiotemporal Ca 2+ cyt patterns. These include pollen tubes, root hairs, moss protonema, algal rhizoids, and single-celled algae. We show that similar spatial and temporal Ca 2+ cyt patterns can be brought about by the coordinated activities of a range of Ca 2+ channel types. Most significantly, these channel types vary widely between different photosynthetic groups, indicating that the conserved necessity to generate spatiotemporal Ca 2+ signals is satisfied by divergent underlying mechanisms, likely reflecting the different evolutionary pressures on ion transport mechanisms across the photosynthetic eukaryote clades.

Background: Platelets contain cytokines and growth factors, which promote wound healing and tissue regeneration. Platelet concentrates, known as platelet-rich plasma (PRP), are used for tissue repair and regeneration in clinical settings. PRP is conventionally prepared by the centrifugation of blood; therefore, blood cells such as erythrocytes and leukocytes cannot be fully eliminated. The purpose of this study was to establish high purification of platelets using dielectrophoresis (DEP) to eliminate blood cells from platelet concentrates. Materials and Methods: The DEP properties of human blood constituents (erythrocytes, leukocytes, and platelets) were characterized. Based on the characterization of DEP properties, PRP was purified to eliminate blood cells using dielectrophoretic and flow-induced shear forces. Results: Erythrocytes and platelets showed similar DEP responses, whereas the crossover frequency of leukocytes differed from those of erythrocytes and platelets. Blood cells can be eliminated from the PRP under specific DEP conditions and flow rates. Conclusion: Blood cells in PRP can be eliminated using DEP and flow-induced shear, with a high platelet recovery rate.

Background:We are all aware of day-to-day healthy stress, but, when sustained for long periods, stress is believed to lead to serious physical and mental health issues.Materials and Methods:In this study, we investigated the potential effects of transcutaneous auricular vagus nerve stimulation (taVNS) on stress processing as reflected in the electrocardiogram (ECG)-derived biomarkers of stress adaptability. Stress reflecting biomarkers included a range of heart rate variability metrics: standard deviation of N-N intervals (SDNN), root mean squared of successive differences in heartbeat intervals (RMSSD), low-frequency component, high-frequency component and their ratio (LF, HF, and LF/HF).In addition, we created a machine learning model capable of distinguishing between the stimulated and nonstimulated conditions from the ECG-derive data from various subjects and states. The model consisted of a deep convolutional neural network, which was trained on R-R interval (RRI) data extracted from ECG and time traces of LF, HF, LF/HF, SDNN, and RMSSD.Results:Only LF/HF ratio demonstrated a statistically significant change in response to stimulation. Although the LF/HF ratio is expected to increase during exposure to stress, we have observed that stimulation during exposure to stress counteracts this increase or even reduces the LF/HF ratio. This could be an indication that the vagus nerve stimulation decreases the sympathetic activation during stress inducement.Our Machine Learning model achieved an accuracy of 70% with no significant variations across the three states (baseline, stress, and recovery). However, training an analogous neural network to identify the states (baseline, stress, and recovery) proved to be unsuccessful.Conclusion:Overall, in this study, we showed further evidence of the beneficial effect of taVNS on stress processing. Importantly we have also demonstrated the promising potential of ECG metrics as a biomarker for the development of closed-loop stimulation systems.

Background: Platelets protect the body from injury through formation of blood clots, changing from a normal, quiescent state to becoming “activated” in response to external stimuli such as chemical cues, shear stress, and temperature. This causes changes in shape, increased adhesion, and alteration of electrical properties such as membrane potential V m and zeta potential ζ . These electrical phenomena have been regarded as largely unconnected; for example, changes in ζ have been attributed solely to alteration of surface lipid concentration. However, recent reports suggest that cells can alter ζ electrostatically by alteration of V m in red blood cells. We hypothesized that if platelets also modulate ζ through V m , this may provide an alternative mechanism to alter cell-cell interaction. Materials and Methods: We investigated platelets stored at different temperatures (4°C, 22°C, and 37°C) for 24 h, which is known to alter platelet behavior and electrical properties, and compared these with analyses of freshly harvested platelets. These four conditions exhibited unique sets of electrical properties ( V m , ζ , membrane conductance G eff , and cytoplasm conductivity σ cyto ), as well as surface exposure of the adhesion molecule P-selectin. These were analyzed to identify correlations between electrical parameters and platelet activation state. Results: Many parameters exhibit pairwise correlation across all four conditions, in particular between ζ and G eff , and between V m and σ cyto . Furthermore, when the electrical behavior of platelets stored at 4°C (known to activate the cells) was removed from the analysis, additional relationships were observed among the remaining conditions, including those connecting ζ and V m to the amount of P-selectin binding. Conclusion: Results suggest that V m may mechanistically alter the availability of cationic molecules at the cell surface, a process never reported before, with implications for our wider understanding of cell-molecule and cell-cell interaction.

Androgen deprivation therapy (ADT) remains a key treatment for advance prostate cancer (PCa), but resistance leads to terminal castrate-resistant prostate cancer (CRPC). Its development is linked to the emergence of a hypoxic tumor microenvironment and associated hypoxia inducible factor (HIF) signaling, which is known to be modulated by intracellular calcium. ADT is also known to upregulate store-operated calcium entry (SOCE) through voltage-gated calcium channel, CaV1.3. Consequently, the role of CaV1.3 in supporting hypoxic signaling and CRPC biology was explored. Androgen-sensitive PCa LNCaP cells were cultured with and without ADT bicalutamide, alongside ADT-resistant CRPC cells (LNCaP-ABL), either in normal or low oxygen (O2) (1%) conditions. HIF-1α, CaV1.3, and androgen receptor (AR) gene expression was measured by qPCR and protein expression with Western blot in the presence or absence of siCaV1.3. SOCE was determined through Fura-2AM fluorescence measurement. Cell proliferation was quantified by WST-1 assay and survival by colony formation. CaV1.3 expression was increased during ADT but not hypoxia, correlating with an associated increase in SOCE. HIF-1α expression was upregulated by ADT under normal O2 conditions and increased during hypoxia across all cells but with a higher fold change in early ADT-resistant and CRPC cells. Under hypoxic conditions CaV1.3 small interfering RNA resulted in a significant reduction in HIF-1α expression for ADT-sensitive cells but increased in CRPC. A similar pattern was also observed for AR expression. Cell survival was found significantly reduced by siCaV1.3 under hypoxic conditions for all cells, with and without ADT. Whereas cell proliferation under the same conditions was reduced in CRPC only. This study highlights that CaV1.3 can modulated HIF signaling and impact on PCa tumor biology under hypoxia, but further investigation is required to ascertain if this mediated through SOCE or a noncanonical mechanism.