Cadmium-induced autophagy and apoptosis are mediated by a calcium signaling pathway

The cytotoxicity of cadmium (Cd) induced autophagy and apoptosis in MES-13 cells was determined by flow cytometry. Autophagy was also assessed by formation of autophagosomes and processing of LC3. Pharmacological inhibition of autophagy resulted in increased of cell viability, suggesting autophagy plays a role in cell death in Cd-treated mesangial cells. Cd also induced a rapid elevation in cytosolic calcium ([Ca²⁺]_i ), and modulation of [Ca²⁺]_i via treatment with IP ₃R inhibitor or knockdown of calcineurin resulted in a change in the proportion of cell death, suggesting that the release of calcium from the ER plays a crucial role in Cd-induced cell death. Inhibition of Cd-induced ERK activation by PD 98059 suppressed Cd-induced autophagy, and BAPTA-AM eliminated activation of ERK. BAPTA-AM also inhibited Cd-induced mitochondrial depolarization and activation of caspases. These findings demonstrated that Cd induces both autophagy and apoptosis through elevation of [Ca²⁺]_i, followed by Ca²⁺-ERK and Ca²⁺-mitochondria-caspase signaling pathways. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. Received 05 July 2008; received after revision 25 August 2008; accepted 17 September 2008     

Minoxidil-induced cardiac hypertrophy in guinea pigs

To investigate whether during cardiac hypertrophy changes occur in contractile protein composition and in mechanical and energetic properties of the myocardium, contractile protein composition, isometric force and adenosine triphosphate (ATP) consumption were studied in control and hypertrophied guinea-pig hearts. Cardiac hypertrophy was induced by adding minoxidil (120 or 200 mg/l) to the drinking water. Protein analysis was performed by one-dimensional gel electrophoresis. The myosin heavy-chain (MHC) composition was determined in an enzyme-linked immunosorbent assay (ELISA). ATP consumption and force development were simultaneously measured during isometric contraction in chemically skinned trabeculae. Histochemical analysis of cross-sectional area of cardiomyocytes and interstitial space was performed on the left ventricular tissue of 200 mg/l minoxidil-treated and control guinea pigs. Minoxidil treatment (120 and 200 mg/l) significantly increased left ventricular dry weight normalized for body weight by 19 ± 4 and 24 ± 4%, respectively. No significant differences were found in the cellular cross-sectional area, while interstitial space was slightly decreased in minoxidil-treated hearts. In left ventricular trabeculae of 200 mg/l minoxidil-treated guinea pigs, ATPase activity was slightly less than in those of control guinea pigs, whereas force did not differ significantly. Calcium sensitivity of force and ATPase activity were not affected by minoxidil treatment. Gel electrophoresis revealed no difference in contractile protein composition, but a tendency towards a lower amount of α-MHC in the minoxidil-treated hearts was found in ELISA. Received 1 February 1999; accepted 15 March 1999     

Regulation of mitochondrial oxidative phosphorylation by second messenger-mediated signal transduction mechanisms

The mitochondrial oxidative phosphorylation system is responsible for providing the bulk of cellular ATP molecules. There is a growing body of information regarding the regulation of this process by a number of second messenger-mediated signal transduction mechanisms, although direct studies aimed at elucidating this regulation are limited. The main second messengers affecting mitochondrial signal transduction are cAMP and calcium. Other second messengers include ceramide and reactive oxygen species as well as nitric oxide and reactive nitrogen species. This review focuses on available data on the regulation of the mitochondrial oxidative phosphorylation system by signal transduction mechanisms and is organised according to the second messengers involved, because of their pivotal role in mitochondrial function. Future perspectives for further investigations regarding these mechanisms in the regulation of the oxidative phosphorylation system are formulated. Received 11 December 2005; received after revision 14 January 2006; accepted 6 February 2006     

Multiple roles of the DSCR1 (Adapt78 or RCAN1) gene and its protein product Calcipressin 1 (or RCAN1) in disease

The DSCR1 (Adapt78) gene¹ is transiently induced by stresses to temporarily protect cells against further potentially lethal challenges. However, chronic expression of the DSCR1 (Adapt78) gene has now been implicated in several pathological conditions including Alzheimer’s disease, Down syndrome and cardiac hypertrophy. Calcipressin 1 has been shown to function through direct binding and inhibition of the serine threonine protein phosphatase Calcineurin. Pharmacological inhibition of calcineurin, by the immunosuppressive drugs cyclosporin A and FK506, affects a wide variety of diseases. It is, therefore, likely that this endogenous calcineurin inhibitor, calcipressin 1, may also play a role in a variety of human diseases. ¹Please note that the mammalian DSCR1 gene is also called Adapt78 or RCAN1, and its protein products have been named Calcipressin1, MCIP1 and RCAN1. A proposal to adopt a single gene name of RCAN1 and a protein name RCAN1 (for Regulator of Calcineurin) has been endorsed by the HUGO Gene Nomenclature Committee, but final approval must await agreement from a majority of researchers in the field. Received 2 March 2005; received after revision 27 May 2005; accepted 19 July 2005     

Testicular compensatory hypertrophy in the unilaterally adrenalectomized lizardMabuya carinata (Schn.)

Unilateral adrenalectomy in recrudescent and breeding phases of the reproductive cycle caused atrophic changes in the ipsilateral testis, shown by inhibition of spermatogenic and steroidogenic activity of the ipsilateral testis. The contralateral testis showed compensatory hypertrophy. Unilateral adrenalectomy in regressing and quiescent phases of the reproductive cycle did not induce compensatory hypertrophy in the contralateral testis although there were atrophic changes in the ipsilateral testis.     

Induction of a 70,000 dalton protein in hypertrophic rat heart

Summary Two-dimensional gel electrophoresis analysis of the product of in vitro translation of polyadenylated RNAs extracted from rat heart rendered hypertrophic by aortic constriction, shows a new protein species not present in the map of control hearts. The same is also obtained when hypertrophy is induced by treatment with thyroxine.     

Ventricular fibrillation threshold during acute ischemia in hypertrophied rat hearts

Summary Ventricular fibrillation threshold was significantly lower in hypertrophied hearts than in normal hearts. Ischemia produced by coronary occlusion reduced fibrillation threshold in both normal and hypertrophied hearts, but the maximum reduction in fibrillation theshold was observed earlier in hypertrophied hearts.     

Methimazole treatment reduces cardiac hypertrophy and mortality without a concomitant reduction in blood pressure in established Goldblatt two-kidney one clip hypertension

The effects of methimazole, and antithyroid drug, on blood pressure and other parameters were evaluated in the established phase of Goldblatt two-kidney one clip (G2K-1C) hypertension. Methimazole was administered via drinking water for five weeks, starting five weeks after hypertension had been induced. After this period of treatment, similarly high blood pressures were observed in methimazole-treated and non-treated G2K-1C rats, despite the fact that a hypothyroid state had been achieved in methimazole-treated rats. Methimazole-treated G2K-1C rats showed reductions in heart rate, ventricular weight, ventricular/body weight ratio and mortality in comparison with rats not treated with methimazole. These results clearly demonstrate that hypothyroidism induced by methimazole: a) does not reverse G2K-1C hypertension, but b) improves the rate of survival and c) reduces relative cardiac hypertrophy, possibly by the reduction in cardiac work observed in Goldblatt hypothyroid rats.     

Calcium transport by red blood cell membranes from young and adult cattle

Summary It is shown using inside-out membrane vesicles that cattle red cells extrude calcium by means of a calmodulin sensitive Ca-pump whose activity is high in calves and extremely low in adult cows. The deline is not due to loss of calmodulin susceptibility nor to a drop in Ca-affinity.     

If phosphatases go up, memory goes down

Previous work has provided conclusive support for a role of various protein kinases in processes underlying learning and memory formation. While these processes are not yet established in full detail, it is interesting to entertain the idea of protein phosphatases being involved in such mechanisms as well. Recent advances in this respect have provided preliminary support of this view. From the pharmacological as well as the transgenic analysis, it appears that especially the calcineurin/inhibitor-1 cascade plays an important role in the transition of intermediate-term into long-term memory formation.     

Failure of calcium to stimulate Na,K-ATPase in the presence of EDTA

Summary The effect of calcium on Na, K-ATPase activity of rat brain homogenates and its modification by the chelating agent EDTA has been investigated. In the absence of EDTA, free calcium (approximately 10^–6mol/l) stimulates Na,K-ATPase activity; in the presence of EDTA the same concentration of free calcium is without effect on the enzyme. In the absence of EDTA the stimulation by calcium of Na,-K-ATPase activity is enhanced by the additional presence of calmodulin but in the presence of EDTA, even when calmodulin is added to excess, calcium still fails to stimulate the enzyme. The possibility that EDTA interferes with an interaction between a calcium-calmodulin complex and Na,K-ATPase is discussed.The expert technical assistance of Mrs Paula Jarvie is gratefully acknowledged. Thanks are due also to Professor Philip Kuchel for assistance with the calculations to determine the concentrations of metal-ligand complexes in the experimental media.     

Blockade by zinc ions of K+-induced contraction and calcium in guinea pigTaenia coli

Preincubation with 0.3 mM Zn²⁺ markedly inhibited both the tonic response and Ca²⁺ binding at low affinity sites induced by K⁺ (60 mM), with smaller effects on the phasic response and the high affinity Ca²⁺ sites, inTaenia coli. However, when the muscle was kept in Zn²⁺-containing medium following the first stimulation with the K⁺, the phasic response and the high affinity Ca²⁺ sites were more severely inhibited during the second stimulation with K⁺. This probably indicates that Zn²⁺ reduced the tonic tension response to K⁺ mainly by inhibiting Ca²⁺ influx at the cell membranes ofTaenia coli. However, when Zn²⁺ is continuously present, Ca²⁺ is not supplied at the storage sites and is not available for the phasic response to a second stimulation with K⁺.     

Effect of the calmodulin inhibitor R24571 (calmidazolium) on rat embryos cultured in vitro

Summary The possible effects of inhibition of the calcium-binding protein, calmodulin, on mammalian morphogenesis have been investigated by culturing rat embryos in vitro from 9 1/2 to 11 1/2 days of development in the presence of R24571 (calmidazolium), a specific inhibitor of calmoldulin. Embryos cultured in 10^–2 mM R24571 for 48 h show inhibited development and exhibit a range of morphogenetic abnormalities including assymetry and neural tube defects. Embryos exposed to R24571 for the first 24 h of a 48 h culture are more severely affected than embryos exposed to R24571 for the last 24 h.Acknowledgments. We wish to thank Mr C. Veltkamp and Mr B. lewis for their expert help with the scanning electron microscopy and photography.     

利用糠醛废水制备醋酸钙镁融雪剂的工艺及产品性能研究

利用糠醛废水中醋酸含量较高的特点,设计了能够在处理糠醛废水的同时回收利用醋酸,生产环保型融雪剂醋酸钙镁（CMA）的工艺条件。并利用该工艺建立了日产5吨CMA的生产线,对所生产的CMA产品的品质和性能进行了评价。研究结果表明：所设计的工艺路线可以用于实际生产,能够回收利用糠醛废水中的水和醋酸,基本实现零排放。所生产的CMA有效成分含量较高,环境影响很小,融雪能力较好,可用于冬季路面的融雪。     

Some extracellular matrix elements as markers of ‘capillary tunnels’ in hypertrophied rat heart

We studied the distribution of the extracellular matrix proteins fibronectin (FN) and laminin (LM) in the hypertrophied hearts of spontaneously hypertensive rats (SHR), using an immunofluorescence method with specific antibodies. The immunohistochemical reaction was positive in the cytoplasm of some hypertrophied cardiomyocytes. The results showed that FN and LM can be used as markers for tunnels, i.e. intracardiocytic invaginations of the sarcolemma. The tunnels observed contained capillaries.     

Role of lipid peroxidation in ferric lactate-enhanced calcium uptake by Ehrlich carcinoma cells

Comparison of Ca²⁺ uptake by Ehrlich carcinoma cells in presence of ferric lactate or aluminum lactate, and formation of thiobarbituric acid-reactive substances, suggests that lipid peroxidation is associated with but not the cause of calcium overload that can lead to cell injury and death.     

Calcitonin-like peptide in the shrimpPalaemon serratus (Crustacea,Decapoda) during the intermolt cycle

Summary A molecule immunologically related to salmon calcitonin has been detected in the hemolymph of the shrimpPalaemon serratus. Its concentration varies inversely with the calcium level during the molt cycle; a maximum (14 ng/ml) is found in the post-molt stage and a minimum (0.5 ng/ml) during the premolt stage.