Modulation Of Calcium Influx Research Articles

Modulation of calcium-influx by carboxymethyl tamarind‑gold nanoparticles promotes biomineralization for tissue regeneration

Gold nanoparticles (AuNPs) have been reported to modulate bone tissue regeneration and are being extensively utilized in biomedical implementations attributable to their low cytotoxicity, biocompatibility and simplicity of functionalization. Lately, biologically synthesized nanoparticles have acquired popularity because of their environmentally acceptable alternatives for diverse applications. Here we report the green synthesis of AuNPs by taking the biopolymer Carboxymethyl Tamarind (CMT) as a unique reducing as well as a stabilizing agent. The synthesized CMT-AuNPs were analyzed by UV–vis spectrophotometer, DLS, FTIR, XRD, TGA, SEM and TEM. These results suggest that CMT-AuNPs possess an average size of 19.93 ± 8.52 nm and have long-term stability. Further, these CMT-AuNPs promote the proliferation together with the differentiation and mineralization of osteoblast cells in a “dose-dependent” manner. Additionally, CMT-AuNPs are non-toxic to SD rats when applied externally. We suggest that the CMT-AuNPs have the potential to be a suitable and non-toxic agent for differentiation and mineralization of osteoblast cells in vitro and this can be tested in vivo as well.

Far-Infrared Ameliorates Pb-Induced Renal Toxicity via Voltage-Gated Calcium Channel-Mediated Calcium Influx.

Far-infrared (FIR), characterized by its specific electromagnetic wavelengths, has emerged as an adjunctive therapeutic strategy for various diseases, particularly in ameliorating manifestations associated with renal disorders. Although FIR was confirmed to possess antioxidative and anti-inflammatory attributes, the intricate cellular mechanisms through which FIR mitigates lead (Pb)-induced nephrotoxicity remain enigmatic. In this study, we investigated the effects of FIR on Pb-induced renal damage using in vitro and in vivo approaches. NRK52E rat renal cells exposed to Pb were subsequently treated with ceramic-generated FIR within the 9~14 μm range. Inductively coupled plasma mass spectrometry (ICP-MS) enabled quantitative Pb concentration assessment, while proteomic profiling unraveled intricate cellular responses. In vivo investigations used Wistar rats chronically exposed to lead acetate (PbAc) at 6 g/L in their drinking water for 15 weeks, with or without a concurrent FIR intervention. Our findings showed that FIR upregulated the voltage-gated calcium channel, voltage-dependent L type, alpha 1D subunit (CaV1.3), and myristoylated alanine-rich C kinase substrate (MARCKS) (p < 0.05), resulting in increased calcium influx (p < 0.01), the promotion of mitochondrial activity, and heightened ATP production. Furthermore, the FIR intervention effectively suppressed ROS production, concurrently mitigating Pb-induced cellular death. Notably, rats subjected to FIR exhibited significantly reduced blood Pb levels (30 vs. 71 μg/mL; p < 0.01), attenuated Pb-induced glomerulosclerosis, and enhanced Pb excretion compared to the controls. Our findings suggest that FIR has the capacity to counteract Pb-induced nephrotoxicity by modulating calcium influx and optimizing mitochondrial function. Overall, our data support FIR as a novel therapeutic avenue for Pb toxicity in the kidneys.

A novel peptide 'T14' reflects age and photo-aging in human skin.

T14 is a 14mer peptide derived from the C-terminus of acetylcholinesterase (AChE). Once cleaved, it is independently bioactive of the parent molecule and enhances calcium influx in different cell types, in a range of scenarios: it binds to an allosteric site selectively on the alpha-7 receptor, where it modulates calcium influx and is thus a potential trophic agent, as already reported in a range of normal developmental scenarios. However, if inappropriately activated, this erstwhile beneficial effect converts to a toxic one, resulting in pathologies as disparate as Alzheimer's and various metastatic cancers. Given that epidermal keratinocyte cells have the same ectodermal origin as brain cells, as well as expressing AChE and the alpha-7 receptor, we have explored whether T14 plays a comparable role. Here we report that the T14 immunoreactivity is detectable in human keratinocytes with levels inversely related to age: this decrease is even more apparent with chronic photo-exposure and thus accelerated skin aging. We conclude that T14, an agent promoting cell growth and renewal in other parts of the body, also operates in skin, Moreover, monitoring of keratinocyte T14 levels might offer further insights into the now well reported link between degenerative diseases and epidermal cell profile.

A Novel Bioactive Peptide, T14, Selectively Activates mTORC1 Signalling: Therapeutic Implications for Neurodegeneration and Other Rapamycin-Sensitive Applications.

T14 modulates calcium influx via the α-7 nicotinic acetylcholine receptor to regulate cell growth. Inappropriate triggering of this process has been implicated in Alzheimer's disease (AD) and cancer, whereas T14 blockade has proven therapeutic potential in in vitro, ex vivo and in vivo models of these pathologies. Mammalian target of rapamycin complex 1 (mTORC1) is critical for growth, however its hyperactivation is implicated in AD and cancer. T14 is a product of the longer 30mer-T30. Recent work shows that T30 drives neurite growth in the human SH-SY5Y cell line via the mTOR pathway. Here, we demonstrate that T30 induces an increase in mTORC1 in PC12 cells, and ex vivo rat brain slices containing substantia nigra, but not mTORC2. The increase in mTORC1 by T30 in PC12 cells is attenuated by its blocker, NBP14. Moreover, in post-mortem human midbrain, T14 levels correlate significantly with mTORC1. Silencing mTORC1 reverses the effects of T30 on PC12 cells measured via AChE release in undifferentiated PC12 cells, whilst silencing mTORC2 does not. This suggests that T14 acts selectively via mTORC1. T14 blockade offers a preferable alternative to currently available blockers of mTOR as it would enable selective blockade of mTORC1, thereby reducing side effects associated with generalised mTOR blockade.

Effect of bovine seminal plasma Binder of Sperm Protein 1 on stallion sperm cryopreservation

Proteins present in seminal plasma directly interact with the plasma membrane of spermatozoa, being important for successful sperm maturation and fertilization. The aim of this work was to evaluate the effect of Binder of Sperm Protein 1 (BSP1) from the seminal vesicle of bulls on semen quality of stallions and its effect on freezability of this semen. The BSP1 protein was isolated using the ammonium sulfate technique and lyophilized. Protein presence was observed at the highest concentration of BSP1 (98%) confirmed by SDS-PAGE and Western blot. The effect of addition of BSP1 to stallion semen was tested at concentrations 0 (control), 10, 20 and 40 μg/mL by addition to a commercial freezing extender. Semen from 4 stallions with 5 ejaculates per stallions was used and cryopreserved using a programmable machine (TK 3000®). After thawing (37°C / 30 seconds), samples were submitted to sperm kinematic analysis by CASA (time 0 hour and Thermo Resistance Test - TRT of 1 hour at 37°C), integrity of plasma membranes (iMP) and acrosomal membrane integrity (iAC; epifluorescence microscopy. The percentage values were subjected to arcsin transformation and means were compared using T-test at 5% probability comparing time 0 vs. TRT of 1 hour. No difference was observed for iMP andiAC regardless of BSP1 concentration. At time 0h there was a difference at the highest BSP1 concentration (40 μg/mL) (P <0.05) for ALH and BCF (control 2,53 ± 0,08a and 40 μg 2,40 ± 0,07b). After 1h TRT, the concentration of 40 μg / mL continued to present a significant difference. Hyperactivation is characterized by an increase in average lateral head displacement (ALH, mm), and beat cross frequency (BCF, Hz), possibly due to an increase in calcium influx. Our results indicate exactly the opposite with a significant reduction in these two parameters. These results suggest that in the horse BSP1 acts modulating calcium influx. Mitochondrial function determined by JC-1 showed a significant difference at the concentration of 10 μg/mL of the protein, lower than the other groups. As the bovine has a higher fertility compared to stallion, these results, in addition to the novelty of the work, allow further studies using proteins from heterologous species with the aim of improving seminal quality in stallions. In conclusion, BSP1 may exert an antioxidant effect in relation to the mitochondrial potential of sperm and change sperm kinematics due to a modulation of calcium influx by BSP1 protein. Further investigations are required to evaluate intracellular calcium concentrations after addition of BSP1.

SIRT1 slows the progression of lupus nephritis by regulating theNLRP3 inflammasome through ROS/TRPM2/Ca2+ channel.

Systemic lupus erythematosus (SLE) is a chronic multisystem inflammatory disease associated with autoantibody formation. Lupus nephritis (LN) is one of the most severe organ manifestations of SLE. The inflammatory response is a key factor in kidney injury, and the NLRP3 inflammasome is frequently associated with the pathogenesis of LN. Sirtuin 1 (SIRT1), a nicotinamide adenine dinucleotide (NAD +)-dependent histone deacetylase, is a promising therapeutic target for preventing renal injury. However, the mechanism of SIRT1 in LN remains unclear. Here, we aimed to investigate the mechanism by which SIRT inhibits the NLRP3 inflammasome to slow the progression of LN. We detected the expression of SIRT1 and the infiltration of macrophages in MRL/lpr mice; the results showed that the expression of SIRT1 was decreased, and the symptoms of lupus nephritis were relieved after the use of resveratrol, which upregulated SIRT1. In vitro studies showed that after lipopolysaccharide (LPS) stimulation, SIRT1 expression decreased, and the NLRP3 inflammasome was activated. Upregulation of SIRT1 inhibits NLRP3 inflammasome activation and assembly by interfering with two signalling pathways. First, SIRT1 affects NF-κB expression, transcription, and inflammatory cytokine expression. Second, SIRT1 modulates calcium influx induced by transient receptor potential channel M2 (TRPM2), which could be partly due to the inhibition of reactive oxygen species (ROS) production. Our findings suggest that upregulated SIRT1 inhibits the NLRP3 inflammasome to slow the progression of lupus nephritis by regulating NF-κB and ROS/TRPM2/Ca2+ channels. This study reveals a new anti-inflammatory mechanism of SIRT1, suggesting that SIRT1 may be a potential therapeutic target for the prevention of LN.

Optimizing precision nanoparticle delivery for magneto-mechanically-based calcium modulation.

Modulating calcium influx events through mechanically actuated magnetic nanoparticles (MNPs) at the cell membrane or in the cytosol of neurons has been trending in the past few years. The mechanical force load is a critical parameter that can be fine-tuned through MNPs concentration and the incubation time. Commonly, MNPs get incubated for 24 h to improve the probability of neuronal uptake; however, critical cellular processes such as protein turnover also coincide during that time frame. Hence, we optimized the incubation time for MNPs to be below <24 h while showing similar calcium response events in neurons. To achieve this goal, we recorded transient calcium fluorescence (Fluo-4 AM, 10x Leica DMI-8, 4 fps) in dissociated primary rat cortical neurons (at 14 days in vitro) with starch-amine functionalized MNPs (incubated for 4 h and 24 h) over 12 min, where a magnetic field actuated 40-80 pN forces on the MNPs from 4 min to 8 min. We decomposed the mean somatic calcium signals into a resting concentration (lower envelope) and calcium events (magnitude and frequency) and correlated them with the Sørenson-Dice. All data was compared with the Mann-Whitney U test (N = 4 cultures, single neuron cells: control = 2262, 4 h = 2424, 24 = 1062). Our results showed that both incubation times provided increases in resting concentration and calcium event frequency and decreased event magnitude and synchronous correlation in comparison to the control. Although similar, we observed that the 4 h incubation time increased the calcium event response with higher frequency and decreased event magnitudes and synchronous correlation when compared to the 24 h incubation. Altogether, our results show that shorter MNPs incubation times can make calcium influx more precise and potentially overcome adverse effects stemming from protein turnover.

Back Cover: Consumption of Artificial Sweetener Acesulfame Potassium Increases Preterm Risk and Uterine Contraction with Calcium Influx Increased via Myosin Light Chain Kinase–Myosin Light Chain 20 Related Signaling Pathway

Mol. Nutr. Food Res. 2022, 66, 202200298 DOI: 10.1002/mnfr.202200298 The usage of non-nutrition sweeteners (NNS) is rapidly increasing in the food industry, with Acesulfame Potassium (Ace K) as the most prevalently consumed NNS in soft drinks. Exposure to Ace K increases the preterm risk, cytokine secretion and uterine hypercontraction through the modulation of calcium influx and alters MLCK/MLC20 contraction related protein expression through c-Jun N-terminal kinase signaling transduction. This is reported by Yang-Ching Chen, Shih-Min Hsia, and co-workers in article number 2200298.

COMPARISON OF THE EFFECTS OF PRE-EMPTIF ANALGESIA PREGABALINE 75 WITH 150 MG ON THE GRADE OF PAIN AND CAESARIAN SECTION SEDATION SCORE WITH SUBARAKHNOID BLOCK

In recent years, many studies have been carried out on the pre-emptive analgesia of pregabalin for various types of surgery with varying results. Preemptive analgesia in caesarean section (SC) usually uses pregabalin at a dose of 150 mg, and there have been no studies using low doses (75 mg) Objective This study aimed to determine the effects of pregabalin 75 mg vs 150 mg doses for controlled pain, their sedation score in patients after C-section under spinal anesthesia. Methods This study was a double-blind randomized trial study examining 20 samples of patients who underwent elective C-sections under spinal anesthesia and divided into 2 equal groups, P75 (who received oral pregabalin 75 mg) and P150 (who received pregabalin 150 mg). The Results There were no significant differences in NRS between the 75 vs 150 mg group (p&gt;0.05), and there were significant differences in Ramsay sedation score between the 75 vs 150 mg group on 2 and 6 hours after surgery(p&lt;0.05) and there were no significant differences about the need for fentanyl rescue between 75 vs 150 mg group (p&gt;0.05). Pregabalin has an opioid-sparing effect and larger doses of pregabalin may increase its efficacy. The sedative effect that arises is due to the mechanism of action of pregabalin which binds potently to the 2δ subunit calcium channel and modulates calcium influx at nerve endings, thereby reducing the release of several excitatory neurotransmitters (glutamate), such as the mechanism of action of various intravenous and inhaled anesthetic agents. Preemptive administration of pregabalin 75 mg is recommended for C-section surgery because it might reduce NRS and the need for fentanyl rescue with minimal sedation side effects.

Phyllanthus muellerianus and Ficus exasperata exhibit anti-proliferative and pro-apoptotic activities in human prostate cancer PC-3 cells by modulating calcium influx and activating caspases

Phyllanthus muellerianus (PM) and Ficus exasperata (FE) are plants used against cancers. We evaluated the phytochemical profiles and in vitro antioxidant potentials of PM and FE, and investigate their effects on cell proliferation, intracellular calcium ([Ca2+]i), caspases 3/9, apoptosis, oxidative stress markers, and Bax/cytochrome C expression in PC-3 cells. The phytochemical profiles were evaluated by liquid chromatography-mass spectrometry (LC‐MS), and the antioxidant by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals scavenging method. The cells were incubated for 24 h with 3% tween 80, paclitaxel (5 nM), PM (800 and 1200 µg/ml), and FE (800 and 1200 µg/ml). After treatments, [Ca2+]i, caspases 3/9, apoptosis and oxidative stress parameters were measured using colorimetric kits, while the mRNA levels of Bax and cytochrome C were quantified by RT‐qPCR. Nitidine, phloridzin and linoleic acid were identified in PM, while docosane, cardanol and chlorogenic acid were revealed in FE. The in vitro antioxidant potential of PM was greater than that of FE. Both plants inhibited the growth of PC-3 cells in a dose-dependent manner, but significantly (p < 0.5–0.001) increased [Ca2+]i, apoptosis level, caspase 3/9 activities, reactive oxygen species production and lipid peroxidation, compared with control. Moreover, the activities of superoxide dismutase, catalase and glutathione peroxidase were significantly decreased in the cells incubated with the plant extracts, PM being the most effective. Paclitaxel, PM and FE upregulated Bax and cytochrome C genes in PC-3 cells. PM and FE inhibited the growth of PC-3 cells by modulating the [Ca2+]i and inducing apoptosis through Bax/Cytochrome C/Caspase 3–9 signaling pathway.

Crbn modulates calcium influx by regulating Orai1 during efferocytosis

Calcium flux regulating intracellular calcium levels is essential and modulated for efficient efferocytosis. However, the molecular mechanism by which calcium flux is modulated during efferocytosis remains elusive. Here, we report that Orai1, a Crbn substrate, is upregulated via its attenuated interaction with Crbn during efferocytosis, which increases calcium influx into phagocytes and thereby promotes efferocytosis. We found that Crbn deficiency promoted phagocytosis of apoptotic cells, which resulted from facilitated phagocytic cup closure and was nullified by a CRAC channel inhibitor. In addition, Orai1 associated with Crbn, resulting in ubiquitination and proteasomal degradation of Orai1 and alteration of SOCE-mediated calcium influx. The association of Orai1 with Crbn was attenuated during efferocytosis, leading to reduced ubiquitination of Orai1 and consequently upregulation of Orai1 and calcium influx. Collectively, our study reveals a regulatory mechanism by which calcium influx is modulated by a Crbn-Orai1 axis to facilitate efferocytosis.

Strategies for Neuroprotection in Multiple Sclerosis and the Role of Calcium.

Calcium ions are vital for maintaining the physiological and biochemical processes inside cells. The central nervous system (CNS) is particularly dependent on calcium homeostasis and its dysregulation has been associated with several neurodegenerative disorders including Parkinson’s disease (PD), Alzheimer’s disease (AD) and Huntington’s disease (HD), as well as with multiple sclerosis (MS). Hence, the modulation of calcium influx into the cells and the targeting of calcium-mediated signaling pathways may present a promising therapeutic approach for these diseases. This review provides an overview on calcium channels in neurons and glial cells. Special emphasis is put on MS, a chronic autoimmune disease of the CNS. While the initial relapsing-remitting stage of MS can be treated effectively with immune modulatory and immunosuppressive drugs, the subsequent progressive stage has remained largely untreatable. Here we summarize several approaches that have been and are currently being tested for their neuroprotective capacities in MS and we discuss which role calcium could play in this regard.

Porcine deltacoronavirus (PDCoV) modulates calcium influx to favor viral replication

Ionic calcium (Ca2+) is a versatile intracellular second messenger that plays important roles in cellular physiological and pathological processes. Porcine deltacoronavirus (PDCoV) is an emerging enteropathogenic coronavirus that causes serious vomiting and diarrhea in suckling piglets. In this study, the role of Ca2+ to PDCoV infection was investigated. PDCoV infection was found to upregulate intracellular Ca2+ concentrations of IPI-2I cells. Chelating extracellular Ca2+ by EGTA inhibited PDCoV replication, and this inhibitory effect was overcome by replenishment with CaCl2. Treatment with Ca2+ channel blockers, particularly the L-type Ca2+ channel blocker diltiazem hydrochloride, inhibited PDCoV infection significantly. Mechanistically, diltiazem hydrochloride reduces PDCoV infection by inhibiting the replication step of the viral replication cycle. Additionally, knockdown of CACNA1S, the L-type Ca2+ voltage-gated channel subunit, inhibited PDCoV replication. The combined results demonstrate that PDCoV modulates calcium influx to favor its replication.

Sex hormone intake in female blood donors: impact on haemolysis during cold storage and regulation of erythrocyte calcium influx by progesterone.

Sex hormone intake in blood donors may affect the quality of red blood cell (RBC) products via modulation of RBC function and predisposition to haemolysis during cold storage. The aims of this study were to evaluate the association between female sex hormone intake and RBC storage outcomes, and to examine possible mechanisms by which sex hormones interact with RBCs. Sex hormone intake by race/ethnicity and menopausal status, and association analyses between hormone intake and donor scores of storage, osmotic or oxidative haemolysis, were evaluated in 6,636 female donors who participated in the National Heart, Lung and Blood Institute's RBC-Omics study. A calcium fluorophore, Fluo-3AM, was used to define RBC calcium influx in response to exogenous sex hormones or transient receptor potential cation (TRPC) channel drugs. Sex hormone intake was more prevalent in premenopausal women from all racial groups (18-31%) than in postmenopausal women (4-8%). Hormone intake was significantly (p<0.0001) associated with reduced storage haemolysis in all females, reduced osmotic haemolysis in postmenopausal donors (23.1±10.2% vs 26.8±12.0% in controls, p<0.001), and enhanced susceptibility to oxidative haemolysis in premenopausal women. In vitro, supraphysiological levels of progesterone (10 μmol/L), but not 17β-oestradiol or testosterone, inhibited calcium influx into RBC and was associated with lower spontaneous haemolysis after 30 days of cold storage (0.95±0.18% vs 1.85±0.35% in controls, p<0.0001) or in response to a TRPC6 activator. Sex hormone intake in female donors is associated with changes in RBC predisposition to haemolysis. Menstrual status and the type of hormone preparation may contribute to differences in haemolytic responses of female RBCs to osmotic and oxidative stress. Progesterone modulates calcium influx into RBC via a mechanism that may involve interactions with membrane TRPC6 channels.

Soluble α-Klotho in Liver Cirrhosis and Alcoholism.

Alpha Klotho is a transmembrane protein that serves as co-receptor for FGF23. Ectodomain of membrane bound α Klotho may be shed by membrane bound proteases (activated, among other factors, by tumor necrosis factor (TNF)-α) generating the soluble form of the protein (sKl) that functions as a hormone by itself. It modulates calcium influx into cells, blunts IGF-1/Insulin signaling, promotes synthesis of antioxidants, generally slows down tumor progression, delays cell senescence, is neuroprotective and promotes oligodendrocyte maturation and myelin synthesis, and muscle rejuvenation. It may be involved in inflammation and exerts antifibrogenic effects. Some of these pathways may become altered in alcoholism or liver cirrhosis, but data are scattered and scarce and an update is required. Literature survey. Alcohol consumption in non-alcoholics is inversely related to sKl, but alcoholic cirrhotics showed higher-than-normal sKl values in association with liver function derangement. In hepatoma cells, the intensity of Klotho staining was related to faster tumor progression and a shortened life span. Among severe alcoholic cirrhotics sKl is directly related to serum TNF-α levels, and, inversely, to brain atrophy. Given the antioxidant, anti-inflammatory, and antifibrogenic effects of Klotho, perhaps the increase in cirrhosis (and in other inflammatory conditions, such as sepsis or cancer) reflects an attempt to regulate increased inflammation, but clinical and experimental research is urgently needed in this field.

Purinergic Receptors Profile in the ARPKD Cystic Epithelia

Polycystic kidney diseases (PKD) are a group of inherited nephropathies marked with the formation of fluid‐filled cysts along the nephron. Growing evidence suggests that autocrine and paracrine effects of purinergic signaling via P2 receptors could detrimentally contribute to cyst expansion. However, little is known about purinergic signaling in renal cyst epithelium, which is characterized by loss of polarity, dedifferentiation and other abnormalities which can lead to purinergic signaling remodeling. We have proposed that ATP via associated intracellular signaling can contribute to cystogenesis by modulation of calcium influx. PCK/CrljCrl‐Pkhd1pck/CRL (PCK) rat, an established model of ARPKD, was used here to test this hypothesis. The cystic fluid of PCK rats and their cortical tissues exhibited significantly higher levels of ATP compared to Sprague Dawley (SD) rat kidney cortical interstitium as assessed by highly sensitive for ATP enzymatic biosensors (211±55 vs 1082±147 nM for SD and PCK cortex correspondingly, and 2,078±391 nM for cystic fluid). Confocal calcium imaging of the freshly isolated cystic monolayers revealed a stronger response to ATP in a higher range of concentrations (above 100 μM). The removal of extracellular calcium results in the absence of ATP evoked transient, which pointed towards the extracellular (ionotropic) calcium entry in cyst‐lining cells rather than the metabotropic P2Y‐mediated internal depot. Application of iso‐PPADS (a non‐selective P2X antagonist) resulted in partial blockade of ATP response (calcium release after ATP was 30.1 ± 0.9, 22.2 ± 1.8 and 19.5 ± 3.2 a.u. in control, after incubation with iso‐PPADS, and after washout, respectively) indicating the contribution of P2X4 purinoreceptor in the cystic monolayer. Next, to specifically assess the role of P2X7 in the ATP‐mediated calcium influx, we employed AZ10606120, a potent P2X7 receptor antagonist. Application of AZ10606120 (5 μM) resulted in a bunted calcium response to ATP (32.4 ± 2.2, 13.5 ± 6.4, and 11.1 ± 3.1 a.u. of total calcium release in control, after incubation with AZ10606120, and after washout, respectively), which corroborates the commonly hypothesized role of P2X7 in cyst development. Further use of pharmacological agents (α,β‐methylene‐ATP, 5‐BDBD, and NF449) allowed to narrow down potential candidate receptors and suggested a significant involvement of the P2X4 and/or P2X7 signaling axis in the regulation of cytosolic calcium level in the cystic epithelia. In conclusion, our ex vivo study provides direct evidence that the profile of P2 receptors is altered in the ARPKD cystic epithelia towards the prevalence of P2X4 and/or P2X7 receptors, which opens new avenues for the treatment of this disease.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Journal Club: Pregnancy outcome following maternal exposure to pregabalin may call for concern.

Owing to its anticonvulsive, analgesic, and anxiolytic properties, pregabalin is used to treat epilepsy, neuropathic pain, and anxiety, respectively. Common side effects include dizziness, lethargy, and drowsiness. Pregabalin is a structural analogue of γ-aminobutyric acid and modulates calcium influx on presynaptic nerve terminals by binding to a subunit on voltage-gated calcium channels.1

PS 11-40 MENTHOL INHIBITS ENHANCED STORE-OPERATED CALCIUM ENTRY IN PLATELETS IS ASSOCIATED WITH PERIPHERAL ARTERY DISEASE FROM HYPERTENSION WITH TYPE 2 DIABETES

Objective: Menthol, a natural compound, is responsible for the minty flavor and smell of the mint plant and is widely used in food and drugs. A recent study showed that menthol modifies PLC signaling, which then leads to changes in cellular functions. Platelet dysfunction plays an important role in thrombosis in diabetes with peripheral artery disease (PAD). Store-operated calcium entry (SOCE) and stromal interaction molecule 1 (STIM1) regulate platelet activity by modulating calcium influx. We hypothesized that enhanced SOCE in platelets is associated with diabetes with PAD. Design and Method: We studied the activity of platelets from healthy participants (NT), type 2 diabetic patients (DM) and hypertension with type 2 diabetes (HDM). Platelet calcium influx and protein expression of STIM1 and sarcoendoplasmic reticulum Ca2+-ATPase 3 (SERCA3) were investigated. Results: Compared with that in platelets from DM, calcium influx was significantly increased in platelets from HDM in the absence of extracellular calcium after the discharge of intracellular Ca2+ stores by thapsigargin. Compared with platelets from DM without PAD, platelets from DM with PAD exhibited significantly increased SOCE. Menthol administration completely inhibited calcium influx in platelets from diabetic patients without PAD, but this effect was blunted in those from diabetic patients with PAD. Furthermore, the increased SOC calcium influx was correlated with the ankle brachial index (ABI) in diabetic patients. High glucose significantly up-regulated STIM1 and SERCA3 protein expression and induced the phosphorylation of phospholipase C (PLC) in platelets from healthy participants. This effect was attenuated in the presence of menthol or U73122, an inhibitor of PLC. Similarly, significant increases in STIM1 and SERCA3 protein expression were found in platelets from diabetic patients compared to those from healthy participants. Conclusions: Platelets from hypertension diabetic patients with PAD exhibited enhanced Store-operated calcium influx, which was associated with elevated STIM1/SERCA3 expression via a PLC-dependent pathway and was inhibited by menthol.

The Actin-Binding Protein Drebrin Inhibits Neointimal Hyperplasia.

Vascular smooth muscle cell (SMC) migration is regulated by cytoskeletal remodeling as well as by certain transient receptor potential (TRP) channels, nonselective cation channels that modulate calcium influx. Proper function of multiple subfamily C TRP (TRPC) channels requires the scaffolding protein Homer 1, which associates with the actin-binding protein Drebrin. We found that SMC Drebrin expression is upregulated in atherosclerosis and in response to injury and investigated whether Drebrin inhibits SMC activation, either through regulation of TRP channel function via Homer or through a direct effect on the actin cytoskeleton. Wild-type (WT) and congenic Dbn(-/+) mice were subjected to wire-mediated carotid endothelial denudation. Subsequent neointimal hyperplasia was 2.4±0.3-fold greater in Dbn(-/+) than in WT mice. Levels of globular actin were equivalent in Dbn(-/+) and WT SMCs, but there was a 2.4±0.5-fold decrease in filamentous actin in Dbn(-/+) SMCs compared with WT. Filamentous actin was restored to WT levels in Dbn(-/+) SMCs by adenoviral-mediated rescue expression of Drebrin. Compared with WT SMCs, Dbn(-/+) SMCs exhibited increased TRP channel activity in response to platelet-derived growth factor, increased migration assessed in Boyden chambers, and increased proliferation. Enhanced TRP channel activity and migration in Dbn(-/+) SMCs were normalized to WT levels by rescue expression of not only WT Drebrin but also a mutant Drebrin isoform that binds actin but fails to bind Homer. Drebrin reduces SMC activation through its interaction with the actin cytoskeleton but independently of its interaction with Homer scaffolds.

Acute effect of 3β-hidroxihop-22(29)ene on insulin secretion is mediated by GLP-1, potassium and calcium channels for the glucose homeostasis

The effect of 3β-hidroxihop-22(29)ene (3-BHO) on insulin and glucagon-like peptide 1 (GLP-1) secretion as well as the mechanism of action of the compound in pancreatic islet on glucose homeostasis was investigated. The data from in vivo treatment show that 3-BHO significantly reduces the hyperglycemia by increasing the insulin and GLP-1 secretion, as well as by accumulating hepatic glycogen in hyperglycemic rats. In rat pancreatic β-cell, 3-BHO stimulates the glucose uptake, insulin vesicles translocation to the plasma membrane and thus the insulin secretion through the involvement of potassium channels (ATP- and Ca2+-dependent K+ channels) and calcium channels (L-type voltage-dependent calcium channels (L-VDCC)). Furthermore, this study also provides evidence for a crosstalk between intracellular high calcium concentration, PKA and PKC in the signal transduction of 3-BHO to stimulate insulin secretion. In conclusion, 3-BHO diminishes glycaemia, stimulates GLP-1 secretion and potentiates insulin secretion and increase hepatic glycogen content. Moreover, this triterpene modulates calcium influx characterizing ATP-K+, Ca2+–K+ and L-VDCC channels-dependent pathways as well as PKA and PKC activity in pancreatic islets underlying the signaling of 3-BHO for the secretory activity and contribution on glucose homeostasis.