Changes In Calcium Homeostasis Research Articles

A Novel Aerosol Foam Formulation of Calcipotriol and Betamethasone Has No Impact on HPA Axis and Calcium Homeostasis in Patients With Extensive Psoriasis Vulgaris.

Background:Fixed combination calcipotriol 50 µg/g (Cal; as hydrate) plus betamethasone 0.5 mg/g (as dipropionate; BD) has been formulated in an innovative aerosol foam.Objective:To assess systemic safety of Cal/BD aerosol foam.Methods:In a multicentre, single-arm, open-label, maximal-use systemic-exposure trial, adult patients with moderate to severe, extensive psoriasis (15%-30% of body surface area, including ≥30% of scalp) applied Cal/BD foam once daily. Endpoints were week 4 abnormal adrenocorticotropic hormone (ACTH) challenge test and change in albumin-corrected serum calcium, 24-hour urinary calcium excretion, and urinary calcium-creatinine ratio.Results:35 patients reaching week 4 exhibited normal ACTH responses. At week 4, changes in calcium homeostasis were minor and not clinically relevant; no patients experienced elevations above normal. Disease severity generally improved, and 49% of patients achieved treatment success according to the Physician’s Global Assessment of Disease Severity.Conclusion:No clinically relevant HPA axis or calcium homeostasis impact was observed with 4 weeks of once-daily Cal/BD foam in patients with extensive psoriasis vulgaris.

Effects of fluvastatin and coenzyme Q10 on skeletal muscle in normo- and hypercholesterolaemic rats

Myalgia and muscle weakness may appreciably contribute to the poor adherence to statin therapy. Although the pathomechanism of statin-induced myopathy is not completely understood, changes in calcium homeostasis and reduced coenzyme Q10 levels are hypothesized to play important roles. In our experiments, fluvastatin and/or coenzyme Q10 was administered chronically to normocholesterolaemic or hypercholaestherolaemic rats, and the modifications of the calcium homeostasis and the strength of their muscles were investigated. While hypercholesterolaemia did not change the frequency of sparks, fluvastatin increased it on muscles both from normocholesterolaemic and from hypercholesterolaemic rats. This effect, however, was not mediated by a chronic modification of the ryanodine receptor as shown by the unchanged ryanodine binding in the latter group. While coenzyme Q10 supplementation significantly reduced the frequency of the spontaneous calcium release events, it did not affect their amplitude and spatial spread in muscles from fluvastatin-treated rats. This indicates that coenzyme Q10 supplementation prevented the spark frequency increasing effect of fluvastatin without having a major effect on the amount of calcium released during individual sparks. In conclusion, we have found that fluvastatin, independently of the cholesterol level in the blood, consistently and specifically increased the frequency of calcium sparks in skeletal muscle cells, an effect which could be prevented by the addition of coenzyme Q10 to the diet. These results support theories favouring the role of calcium handling in the pathophysiology of statin-induced myopathy and provide a possible pathway for the protective effect of coenzyme Q10 in statin treated patients symptomatic of this condition.

Structure-based drug design studies of the interactions of ent-kaurane diterpenes derived from Wedelia paludosa with the Plasmodium falciparum sarco/endoplasmic reticulum Ca²⁺-ATPase PfATP6.

Malaria is responsible for more deaths around the world than any other parasitic disease. Due to the emergence of strains that are resistant to the current chemotherapeutic antimalarial arsenal, the search for new antimalarial drugs remains urgent though hampered by a lack of knowledge regarding the molecular mechanisms of artemisinin resistance. Semisynthetic compounds derived from diterpenes from the medicinal plant Wedelia paludosa were tested in silico against the Plasmodium falciparum Ca2+-ATPase, PfATP6. This protein was constructed by comparative modelling using the three-dimensional structure of a homologous protein, 1IWO, as a scaffold. Compound 21 showed the best docking scores, indicating a better interaction with PfATP6 than that of thapsigargin, the natural inhibitor. Inhibition of PfATP6 by diterpene compounds could promote a change in calcium homeostasis, leading to parasite death. These data suggest PfATP6 as a potential target for the antimalarial ent-kaurane diterpenes.

PMCA4 (ATP2B4) mutation in familial spastic paraplegia causes delay in intracellular calcium extrusion.

BackgroundFamilial spastic paraplegia (FSP) is a heterogeneous group of disorders characterized primarily by progressive lower limb spasticity and weakness. More than 50 disease loci have been described with different modes of inheritance. Recently, we described a novel missense mutation (c.803G>A, p.R268Q) in the plasma membrane calcium ATPase (PMCA4, or ATP2B4) gene in a Chinese family with autosomal dominant FSP. Further to this finding, here we describe the functional effect of this mutation.MethodsAs PMCA4 removes cytosolic calcium, we measured transient changes and the time-dependent decay of cytosolic calcium level as visualized by using fura-2 fluorescent dye with confocal microscopy in human SH-SY5Y neuroblastoma cells overexpressing either wild-type or R268Q mutant PMCA4.ResultsOverexpressing both wild-type and R268Q PMCA4 significantly reduced maximum calcium surge after KCl-induced depolarization as compared with vector control cells. However, cells overexpressing mutant PMCA4 protein demonstrated significantly higher level of calcium surge when compared with wild-type. Furthermore, the steady-state cytosolic calcium concentration in these mutant cells remained markedly higher than the wild-type after SERCA inhibition by thapsigargin.ConclusionOur result showed that p.R268Q mutation in PMCA4 resulted in functional changes in calcium homeostasis in human neuronal cells. This suggests that calcium dysregulation may be associated with the pathogenesis of FSP.

Calpain activation and CaMKIV reduction in spinal cords from hSOD1G93A mouse model.

Amyotrophic Lateral Sclerosis (ALS), a severe neurodegenerative disease, affects the upper and lower motor neurons in the brain and spinal cord. In some studies, ALS disease progression has been associated with an increase in calcium-dependent degeneration processes. Motoneurons are specifically vulnerable to sustained membrane depolarization and excessive elevation of intracellular calcium concentration. The present study analyzed intracellular events in embryonic motoneurons and adult spinal cords of the hSOD1G93A ALS mouse model. We observed activation of calpain, a calcium-dependent cysteine protease that degrades a variety of substrates, and a reduction in calcium-calmodulin dependent protein kinase type IV (CaMKIV) levels in protein extracts from spinal cords obtained at several time-points of hSOD1G93A mice disease progression. However, in cultured embryonic motoneurons these differences between controls and hSOD1G93A mutants are not evident. Our results support the hypothesis that age-dependent changes in calcium homeostasis and resulting events, e.g., calpain activation and CaMKIV processing, are involved in ALS pathogenesis.

Fluoxetine prevents dystrophic changes in a zebrafish model of Duchenne muscular dystrophy.

Duchenne muscular dystrophy (DMD) is a common and relentlessly progressive muscle disease. Some interventions have been identified that modestly slow progression and prolong survival, but more meaningful therapies are lacking. The goal of this study is to identify new therapeutic pathways for DMD using a zebrafish model of the disease. To accomplish this, we performed a non-biased drug screen in sapje, a zebrafish line with a recessive nonsense mutation in dystrophin. We identified 6 positive hits (out of 640 total drugs tested) by their ability to prevent abnormal birefringence in sapje. Follow-up analyses demonstrated that fluoxetine, a selective serotonin reuptake inhibitor (SSRI), provided the most substantial benefit. Morpholino-based experimentation confirmed that modulation of the serotonin pathway alone can prevent the dystrophic phenotype, and transcriptomic analysis revealed changes in calcium homeostasis as a potential mechanism. In all, we demonstrate that monoamine agonists can prevent disease in a vertebrate model of DMD. Given the safe and widespread use of SSRIs in clinical practice, our study identifies an attractive target pathway for therapy development.

Age-related downregulation of the CaV3.1 T-type calcium channel as a mediator of amyloid beta production

Alzheimer's is a crippling neurodegenerative disease that largely affects aged individuals. Decades of research have highlighted age-related changes in calcium homeostasis that occur before and throughout the duration of the disease, and the contributions of such dysregulation to Alzheimer's disease pathogenesis. We report an age-related decrease in expression of the CaV3.1 T-type calcium channel at the level of messenger RNA and protein in both humans and mice that is exacerbated with the presence of Alzheimer's disease. Downregulating T-type calcium channels in N2a cells and the 3xTg-AD mouse model of Alzheimer's disease, by way of pharmacologic inhibition with NNC-55-0396, results in a rapid increase in amyloid beta production via reductions in non-amyloidogenic processing, whereas genetic overexpression of the channel in human embryonic kidney cells expressing amyloid precursor protein produces complementary effects. The age-related decline in CaV3.1 expression may therefore contribute to a pro-amyloidogenic environment in the aging brain and represents a novel opportunity to intervene in the course of Alzheimer's disease pathogenesis.

Angiostatic Factors in the Pulmonary Endarterectomy Material from Chronic Thromboembolic Pulmonary Hypertension Patients Cause Endothelial Dysfunction

Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare disease with persistent thrombotic occlusion or stenosis of the large pulmonary arteries resulting in pulmonary hypertension. Surgical removal of the neointimal layer of these vessels together with the non-resolved thrombus consisting of organized collagen-rich fibrotic areas with partly recanalized regions is the treatment of choice (pulmonary endarterectomy, PEA). The present study investigates endothelial cells isolated from such material as well as factors present in the surgical PEA material, which may contribute to impairment of recanalization and thrombus non-resolution. We observed muscularized vessels and non-muscularized vessels in the PEA material. The isolated endothelial cells from the PEA material showed significantly different calcium homeostasis as compared to pulmonary artery endothelial cells (hPAECs) from normal controls. In the supernatant (ELISA) as well as on the tissue level (histochemical staining) of the PEA material, platelet factor 4 (PF4), collagen type I and interferon-gamma-inducible 10 kD protein (IP-10) were detected. CXCR3, the receptor for PF4 and IP-10, was particularly elevated in the distal parts of the PEA material as compared to human control lung (RT-PCR). PF4, collagen type I and IP-10 caused significant changes in calcium homeostasis and affected the cell proliferation, migration and vessel formation in hPAECs. The presence of angiostatic factors like PF4, collagen type I and IP-10, as recovered from the surgical PEA material from CTEPH patients, may lead to changes in calcium homeostasis and endothelial dysfunction.

Changes in calcitropic hormones, bone markers and insulin-like growth factor I (IGF-I) during pregnancy and postpartum: a controlled cohort study

Pregnancy and lactation cause major changes in calcium homeostasis and bone metabolism. This population-based cohort study presents the physiological changes in biochemical indices of calcium homeostasis and bone metabolism during pregnancy and lactation We describe physiological changes in calcium homeostasis, calcitropic hormones and bone metabolism during pregnancy and lactation. We studied 153 women planning pregnancy (n=92 conceived) and 52 non-pregnant, age-matched female controls. Samples were collected prior to pregnancy, once each trimester and 2, 16 and 36 weeks postpartum. The controls were followed in parallel. P-estradiol (E2), prolactin and 1,25-dihydroxyvitamin D (1,25(OH)2D) increased (p<0.001) during pregnancy, whereas plasma levels of parathyroid hormone (P-PTH) and calcitonin decreased (p<0.01). Insulin-like growth factor I (IGF-I) was suppressed (p<0.05) in early pregnancy but peaked in the third trimester. Postpartum, E2 was low (p<0.05); prolactin decreased according to lactation status (p<0.05). 1,25(OH)2D was normal and IGF-I was again reduced (p<0.05). P-PTH and calcitonin increased postpartum. From early pregnancy, markers of bone resorption and formation rose and fall, respectively (p<0.001). From the third trimester, bone formation markers increased in association with IGF-I changes (p<0.01). Postpartum increases in bone turnover markers were associated with lactation status (p<0.001). During lactation, plasma phosphate was increased, whereas calcium levels tended to be decreased which may stimulate PTH levels during and after prolonged lactation. The increased calcium requirements in early pregnancy are not completely offset by increased intestinal calcium absorption caused by high 1,25(OH)2D since changes in bone markers indicated a negative bone balance. The rise in bone formation in late pregnancy may be initiated by a spike in IGF-I levels. The high bone turnover in lactating women may be related to high prolactin and PTH levels, low E2 levels and perhaps increased parathyroid hormone-related protein levels.

Lethal, Hereditary Mutants of Phospholamban Elude Phosphorylation by Protein Kinase A

The sarcoplasmic reticulum calcium pump (SERCA) and its regulator, phospholamban, are essential components of cardiac contractility. Phospholamban modulates contractility by inhibiting SERCA, and this process is dynamically regulated by β-adrenergic stimulation and phosphorylation of phospholamban. Herein we reveal mechanistic insight into how four hereditary mutants of phospholamban, Arg(9) to Cys, Arg(9) to Leu, Arg(9) to His, and Arg(14) deletion, alter regulation of SERCA. Deletion of Arg(14) disrupts the protein kinase A recognition motif, which abrogates phospholamban phosphorylation and results in constitutive SERCA inhibition. Mutation of Arg(9) causes more complex changes in function, where hydrophobic substitutions such as cysteine and leucine eliminate both SERCA inhibition and phospholamban phosphorylation, whereas an aromatic substitution such as histidine selectively disrupts phosphorylation. We demonstrate that the role of Arg(9) in phospholamban function is multifaceted: it is important for inhibition of SERCA, it increases the efficiency of phosphorylation, and it is critical for protein kinase A recognition in the context of the phospholamban pentamer. Given the synergistic consequences on contractility, it is not surprising that the mutants cause lethal, hereditary dilated cardiomyopathy.

Prospective impact of 5-FU in the induction of endoplasmic reticulum stress, modulation of GRP78 expression and autophagy in Sk-Hep1 cells

Hepatocellular carcinoma (HCC) is one of the most aggressive malignant diseases and is highly resistant to conventional chemotherapy. Therefore, HCC requires more effective prevention and treatment strategies. 5-fluorouracil (5-FU) remains the most widely used chemotherapeutic drug for the treatment of gastrointestinal, breast, head and neck, and ovarian cancers. In pursuit of a novel effective strategy, we have evaluated the potential of 5-FU to promote endoplasmic reticulum (ER) stress and autophagy in Sk-Hep1 HCC cells. We found that 5-FU profoundly induces ER stress in Sk-Hep1 cells and upregulates p53 and activates CHOP/GADD153 and caspase-12. Activation of CHOP/GADD153 and caspase-12 promotes mitochondrial cell death in Sk-Hep1 cells followed by ER stress. Changes in calcium homeostasis and the protein folding machinery cause stress in the ER, leading to apoptotic cell death. Stress in the ER activates autophagy to remove the misfolded protein aggregates and recover from the stress environment. Our study demonstrates that 5-FU-induced ER stress suppresses autophagy and also downregulates GRP78 expression. Activation of autophagy followed by ER stress facilitates the cell survival response. Therefore, the inhibition of protective autophagy may provide a useful pharmacological target. Taken together, these results indicate that 5-FU-induced ER stress activates the mitochondrial apoptotic cell death pathway by downregulating GRP78 and protective autophagy proteins in Sk-Hep1 cells, raising the possibility of using 5-FU as a therapeutic agent to target human HCC.

Fracture Risk in Living Kidney Donors: A Matched Cohort Study

Chronic kidney disease increases the risk of bone fragility fractures (osteoporotic fractures). Living kidney donors lose 50% of their renal mass and show changes in calcium homeostasis. We studied whether living kidney donation increases the risk of fragility fracture. Retrospective matched-cohort study. We reviewed the medical charts of all 2,015 adults in Ontario, Canada, who donated a kidney between 1992 and 2009 (surgeries performed across 5 transplant programs). We linked this information to health care databases and randomly selected 20,150 matched nondonors from the healthiest portion of the general population. Median age was 43 (95% CI, 24-50) years at study enrollment. Donors and nondonors were then followed up for a median of 6.6 years and a maximum of 17.7 years. Living donor nephrectomy. The primary outcome was lower- and upper-extremity fragility fractures. Individuals who reached 66 years or older in follow-up had bisphosphonate prescriptions recorded. The rate of fragility fracture was no higher in donors compared with nondonors (16.4 vs 18.7 events/10,000 person-years; rate ratio, 0.88; 95% CI, 0.58-1.32). Results were similar in multiple additional analyses. There was little difference in the proportion of older adults in follow-up who received a bisphosphonate prescription (17.1% vs 15.2%; P = 0.4). These are interim results. Ongoing surveillance of this and other donor cohorts is warranted to be sure an association does not manifest with longer follow-up. To date, there is no evidence of increased fragility fracture risk in living kidney donors. Our results meet an information need and are reassuring for the safety of the practice.

Endoplasmic Reticulum (ER) Stress inhibition via S‐methyl‐N, N‐diethylthiocarbamate sulfoxide (DETC‐MeSO) in Focal Cerebral Artery Occlusion in Rat

ER functions can be disturbed after excitotoxicity which leads to changes in calcium homeostasis. One approach for protecting neurons from excitotoxic damage is blocking of NMDA receptors with specific antagonists. We investigated the neuroprotective effect of DETC‐MeSO, a partial antagonist of NMDA receptors in the rat stroke model. Focal cerebral ischemia was induced by occlusion of the left middle cerebral artery for 2 hours. DETC‐MeSO (5.6 mg/kg) was administered subcutaneously for 4 days, then rats were sacrificed and infarct size in the left hemisphere was measured by TTC staining. Western Blotting on the core and the penumbra tissue of both hemispheres was done for analysis of the expression of key proteins involved in apoptosis (Bax, Bcl‐2), heat shock proteins (HSP27, HSP70), GRP78, ER stress markers (IRE1, PERK and ATF6 pathways) and p‐AKT. TTC staining showed that DETC‐MeSO can decrease the lesion volume size in the left hemisphere. Up‐regulation of Bcl‐2 to Bax ratio was seen in the core and the penumbra of treatment group. HSP27 and p‐AKT protein expression were increased in the core and the penumbra of treated group, while HSP70 and GRP78 protein expression showed no changes. Our data indicated that the administration of DETC‐MeSO can attenuate ER stress, mostly via IRE1 pathway mediated by down‐regulation of IRE1α, Ask1, JNK and GADD34 proteins and up‐regulation of Bcl‐2 protein.Grant Funding Source: Florida Department of Health

Reticulon Protein-1C: A New Hope in the Treatment of Different Neuronal Diseases.

Reticulons (RTNs) are a group of membrane proteins localized on the ER and known to regulate ER structure and functions. Several studies have suggested that RTNs are involved in different important cellular functions such as changes in calcium homeostasis, ER-stress-mediated cell death, and autophagy. RTNs have been demonstrated to exert a cancer specific proapoptotic function via the interaction or the modulation of specific proteins. Reticulons have also been implicated in different signaling pathways which are at the basis of the pathogenesis of several neurodegenerative diseases. In this paper we discuss the accumulating evidence identifying RTN-1C protein as a promising target in the treatment of different pathologies such as cancer or neurodegenerative disorders.

Amyotrophic Lateral Sclerosis IgGs Enhance the Mobility of Lysotracker-Labelled Vesicles in Cultured Rat Astrocytes

We examined the effect of purified immunoglobulins G (IgG) from amyotrophic lateral sclerosis (ALS) patients on the mobility and exocytotic release from Lysotracker-stained vesicles in cultured rat astrocytes. Time-lapse confocal images were acquired and vesicle mobility analyzed before and after the application of ALS IgG. The vesicle counts were obtained to assess cargo exocytosis from stained organelles. At rest, when mobility was monitored for 2 minutes in bath with Ca2+, two vesicle populations were discovered: i) non-mobile vesicles (6.1%) with total track length (TL) 1 μm, averaging at 3.03±0.01 μm (n=20200). ALS IgG (0.1 mg/ml) from 12 out of 13 patients increased the TL of mobile vesicles by ∼24% and maximal displacement (MD) by ∼26% within 4 minutes, while the IgG from control group did not alter the vesicle mobility. The mobility enhancement by ALS IgG was reduced in extracellular solution devoid of Ca2+, indicating that ALS-IgG vesicle mobility-enhancement involves changes in Ca2+ homeostasis. To examine, if enhanced mobility relates to elevated Ca2+ activity, cells were stimulated by 1 mM ATP, a cytosolic Ca2+ increasing agent, in the presence (2 mM) and in the absence of extracellular Ca2+. ATP stimulation triggered an increase in TL by ∼7% and ∼12%, and a decrease in MD by ∼11% and ∼1%, within 4 minutes respectively. Interestingly none of the stimuli triggered the release of vesicle cargo. It is concluded that ALS IgG-enhanced vesicle mobility in astrocytes engages changes in calcium homeostasis.

Calcium homeostasis and body composition in patients with palmoplantar pustulosis: a case-control study

Palmoplantar pustulosis (PPP) is a common disease strongly associated with smoking, autoimmune comorbidities and a deranged calcium homeostasis. It is unclear whether these changes in calcium homeostasis are a consequence of vitamin D status, abnormal dermal vitamin D synthesis or whether they are substantiated in effects on bone mineral density (BMD). To study the vitamin D status and BMD in patients with PPP. In comparisons with two sets of controls (n=101 for serum analyses and n=5123 for BMD analyses), we therefore aimed to investigate whether PPP (59 cases) was associated with serum levels of 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D, whether patients with PPP had decreased BMD and finally if the dermal expression of 25-hydroxyvitamin D(3) -1α-hydroxylase (CYP27B1) and the vitamin D receptor (VDR) were affected in PPP skin lesions. We found no differences in mean serum 25-hydroxyvitamin D levels between cases and controls, whereas PPP cases displayed 17·8 pmol L(-1) lower (P=0·04) values in 1,25-dihydroxyvitamin D. BMD at the hip, lumbar spine or of total body did not differ substantially between cases and controls. Finally, patients with PPP had lower dermal expression of CYP27B1 and VDR in affected skin lesions. The increase in serum calcium levels and suppressed parathyroid hormone in patients with PPP were not attributable to derangements in vitamin D status and these patients did not have lower BMD.

Changes in the distribution of calbindin D28-k, parvalbumin, and calretinin in the hippocampus of the circling mouse

The circling (cir) mouse strain, a murine model of deafness caused by a spontaneous mutation, exhibits characteristic behaviors of circling and hyperactivity. In an induced-noise paradigm, cir mice display a significant loss in their spatial orientation abilities, and this has been suggested to be due at least in part to changes in calcium homeostasis. Auditory information is transferred from the cochlear nucleus to the hippocampus, where it is processed to modulate motor and sensory activity. Such a pathway could be affected at the cellular level by alterations in neurotransmission, including alterations that involve Ca2+. However, there have been no studies in a hearing deficit model examining the concomitant molecular alterations in the hippocampus. Thus, in the present study we used immunohistochemistry to compare the distribution of the calcium-binding proteins (CaBPs) calbindin D-28k, parvalbumin, and calretinin in the hippocampi of heterozygous (+/cir), homozygous (cir/cir), and wild-type (+/+) mice. The expression of the CaBPs in various hippocampal subfields appeared to be significantly lower in cir mice (+/− and −/−) than in +/+ mice. Such a decrease in CaBP expression in cir/cir mice would alter calcium homeostasis, which in turn could affect the connection of the tri-synaptic circuit of the hippocampus as well as the cortical region. A decrease in CaBPs and the probable resultant glutamate-mediated excitability could contribute to the functional changes that lead to the characteristic behavioral features of cir mice.

Amyotrophic lateral sclerosis immunoglobulins G enhance the mobility of Lysotracker-labelled vesicles in cultured rat astrocytes

We examined the effect of purified immunoglobulins G (IgG) from patients with amyotrophic lateral sclerosis (ALS) on the mobility and exocytotic release from Lysotracker-stained vesicles in cultured rat astrocytes. Time-lapse confocal images were acquired, and vesicle mobility was analysed before and after the application of ALS IgG. The vesicle counts were obtained to assess cargo exocytosis from stained organelles. At rest, when mobility was monitored for 2 min in bath with Ca(2+), two vesicle populations were discovered: (1) non-mobile vesicles (6.1%) with total track length (TL) < 1 μm, averaging at 0.33 ± 0.01 μm (n = 1305) and (2) mobile vesicles (93.9%) with TL > 1 μm, averaging at 3.03 ± 0.01 μm (n = 20,200). ALS IgG (0.1 mg mL(-1)) from 12 of 13 patients increased the TL of mobile vesicles by approx. 24% and maximal displacement (MD) by approx. 26% within 4 min, while the IgG from control group did not alter the vesicle mobility. The mobility enhancement by ALS IgG was reduced in extracellular solution devoid of Ca(2+), indicating that ALS IgG vesicle mobility enhancement involves changes in Ca(2+) homeostasis. To examine whether enhanced mobility relates to elevated Ca(2+) activity, cells were stimulated by 1 mm ATP, a cytosolic Ca(2+) increasing agent, in the presence (2 mm) and in the absence of extracellular Ca(2+). ATP stimulation triggered an increase in TL by approx. 7% and 12% and a decrease in MD by approx. 11% and 1%, within 4 min respectively. Interestingly, none of the stimuli triggered the release of vesicle cargo. Amyotrophic lateral sclerosis-IgG-enhanced vesicle mobility in astrocytes engages changes in calcium homeostasis.

Gene Expression of Calcium Channel Components in Dahl Salt‐Resistant Rat Mesenteric Arteries by RT‐PCR

We aim to determine the modulation in gene expression levels of proteins involved in calcium membrane transport in the vasculature. Calcium homeostasis in resistant arteries has been associated with hypertension. We have studied gene expression of proteins associated with a number of calcium handling components in mesenteric arteries from hypertensive and normotensives rats. Mesenteric artery tissue was isolated from the Dahl salt-sensitive rats on high and low salt diet and homogenized using a sonicator. The RNA was isolated and purified according to Qiagen instructions. cDNA was synthesized, consequently purified and 20 ng of the sample was used for analysis of 60 relevant genes by RT-PCR. We utilize detailed mathematical models of calcium dynamics in vascular cells to relate different expression levels to macroscopic changes in Calcium homeostasis between hypertensive and normotensive vessels.

Mechanism of cytotoxic action of perfluorinated acids. III. Disturbance in Ca 2+ homeostasis

The global distribution of perfluorinated acids (PFAs) in industry and in household is well known. Their increasing environmental occurrence and biomagnification in the living organisms have drawn growing interests in efforts to describe precisely the mechanisms of action in vitro and in vivo. Our previous investigations widely described lipophilicity-dependent cytotoxicity of PFAs as well as the effect of perfluorination of carbon chain on depolarization of plasma membrane potential, acidification or mitochondrial dysfunctions. In this study we presented in dose- and time-dependent manner the impact of PFAs on calcium homeostasis in HCT116 cells. Comparative analysis of cytosolic [Ca 2+] c and mitochondrial calcium [Ca 2+] m carried out by flow cytometry revealed distinct uptake of calcium into mitochondria in correlation to increasing lipophilicity of PFAs. Massive accumulation of [Ca 2+] m was not accompanied by equivalent loss of [Ca 2+] c. Indeed, moderate changes of [Ca 2+] c were observed after incubation with 400 μM PFDoDA reaching 29.83% and 49.17% decrease at 4th and 72nd hour, respectively. At the same time, mitochondrial calcium uptake increased from 2- to more than 4-fold comparing with non-treated cells. Incubation with non-fluorinated decanoic acid (DA) did not cause any changes in calcium homeostasis. Presented data show that PFAs-induced perturbations in calcium distribution seem to be a missing link related to mitochondria dysfunction playing a crucial role in determination of apoptotic cell death. Complete scheme for the mechanism of cytotoxic action of PFAs has been included.