Inhibition of SOC/Ca2+/NFAT pathway is involved in the anti-proliferative effect of sildenafil on pulmonary artery smooth muscle cells

<p>Abstract</p> <p>Background</p> <p>Sildenafil, a potent phosphodiesterase type 5 (PDE5) inhibitor, has been proposed as a treatment for pulmonary arterial hypertension (PAH). The mechanism of its anti-proliferative effect on pulmonary artery smooth muscle cells (PASMC) is unclear. Nuclear translocation of nuclear factor of activated T-cells (NFAT) is thought to be involved in PASMC proliferation and PAH. Increase in cytosolic free [Ca²⁺] ([Ca²⁺]_i) is a prerequisite for NFAT nuclear translocation. Elevated [Ca²⁺]_iin PASMC of PAH patients has been demonstrated through up-regulation of store-operated Ca²⁺channels (SOC) which is encoded by the transient receptor potential (TRP) channel protein. Thus we investigated if: 1) up-regulation of TRPC1 channel expression which induces enhancement of SOC-mediated Ca²⁺influx and increase in [Ca²⁺]_iis involved in hypoxia-induced PASMC proliferation; 2) hypoxia-induced promotion of [Ca²⁺]_ileads to nuclear translocation of NFAT and regulates PASMC proliferation and TRPC1 expression; 3) the anti-proliferative effect of sildenafil is mediated by inhibition of this SOC/Ca²⁺/NFAT pathway.</p> <p>Methods</p> <p>Human PASMC were cultured under hypoxia (3% O₂) with or without sildenafil treatment for 72 h. Cell number and cell viability were determined with a hemocytometer and MTT assay respectively. [Ca²⁺]_iwas measured with a dynamic digital Ca²⁺imaging system by loading PASMC with fura 2-AM. TRPC1 mRNA and protein level were detected by RT-PCR and Western blotting respectively. Nuclear translocation of NFAT was determined by immunofluoresence microscopy.</p> <p>Results</p> <p>Hypoxia induced PASMC proliferation with increases in basal [Ca²⁺]_iand Ca²⁺entry via SOC (SOCE). These were accompanied by up-regulation of TRPC1 gene and protein expression in PASMC. NFAT nuclear translocation was significantly enhanced by hypoxia, which was dependent on SOCE and sensitive to SOC inhibitor SKF96365 (SKF), as well as cGMP analogue, 8-brom-cGMP. Hypoxia-induced PASMC proliferation and TRPC1 up-regulation were inhibited by SKF and NFAT blocker (VIVIT and Cyclosporin A). Sildenafil treatment ameliorated hypoxia-induced PASMC proliferation and attenuated hypoxia-induced enhancement of basal [Ca²⁺]_i, SOCE, up-regulation of TRPC1 expression, and NFAT nuclear translocation.</p> <p>Conclusion</p> <p>The SOC/Ca²⁺/NFAT pathway is, at least in part, a downstream mediator for the anti-proliferative effect of sildenafil, and may have therapeutic potential for PAH treatment.</p

The mechanisms by which polyamines accelerate tumor spread

Increased polyamine concentrations in the blood and urine of cancer patients reflect the enhanced levels of polyamine synthesis in cancer tissues arising from increased activity of enzymes responsible for polyamine synthesis. In addition to their de novo polyamine synthesis, cells can take up polyamines from extracellular sources, such as cancer tissues, food, and intestinal microbiota. Because polyamines are indispensable for cell growth, increased polyamine availability enhances cell growth. However, the malignant potential of cancer is determined by its capability to invade to surrounding tissues and metastasize to distant organs. The mechanisms by which increased polyamine levels enhance the malignant potential of cancer cells and decrease anti-tumor immunity are reviewed. Cancer cells with a greater capability to synthesize polyamines are associated with increased production of proteinases, such as serine proteinase, matrix metalloproteinases, cathepsins, and plasminogen activator, which can degrade surrounding tissues. Although cancer tissues produce vascular growth factors, their deregulated growth induces hypoxia, which in turn enhances polyamine uptake by cancer cells to further augment cell migration and suppress CD44 expression. Increased polyamine uptake by immune cells also results in reduced cytokine production needed for anti-tumor activities and decreases expression of adhesion molecules involved in anti-tumor immunity, such as CD11a and CD56. Immune cells in an environment with increased polyamine levels lose anti-tumor immune functions, such as lymphokine activated killer activities. Recent investigations revealed that increased polyamine availability enhances the capability of cancer cells to invade and metastasize to new tissues while diminishing immune cells' anti-tumor immune functions

KEGIATAN PENELITIAN PERGURUAN TINGGI STUDI POTENSI REPRODUKSI KAMBING BERANAK LEBIH DARI MIA EKOR PER KELAHIRAN SEBAGAI DASAR PENMBENTUKAN KELOMPOK KAMBING BERANAK BANYAK

Research on kidding ability of ewes had been conducted at Singorojo, Kendal Resident. The aim of the research was to find out a maternal ability of ewes giving a birth more than two kids (n = 26 head). The sample was chosen by using purposive randomized sampling. Result showed that there was no significantly difference between sample and both single and twins, based on body weight, body height, body tenet!), chest width, chest depth, facial profile, hip hair and udder shape. Characteristic of facial profile, hip hair and udder shape of sample found showed that there was difference between sample goats and both Kacang and Ettawah Crossbred Goats at 3 head (11,54%) and 2 head (3,85%). respectively. Moreover, the identification of sample related to facial profile was facial convex and facial straight at 14 head (53,85%) and 6 head (23,08%), respectively. Dalam usaha ternak proses reproduksi merupakan suatu gerbang untuk menuju ke arah produksi maupun pelestarian suatu ternak. Keberhasilan di bidang reproduksi akan meningkatkan pendapatkan peternak, mempenahankan keberadaan limns ternak, menjaga ketersediaan makanan bergizi asal ternak,sena menyediakan bahan industrO kerajinan. • Dewasa ini, peningkatan populasi ternak ruminansia di Indonesia masth sanuat suit dicapai, meskipun sudah banyak jalan yang ditempuh, apalagi peningkatan kualitas dan kualitas produk ternak ruminan tersebut. Dalam usaha peningkatan populasi kambing dapat ditempuh dengan jalan mencari kambing-kambing yang mempunyai kemainpuan beranak lebih dari dua perkelahiran untuk digunakan sebagai bibit. Berdasarkan hal tersebut nenelitian ini bermaksud mengetahui potensi kambing-kambing yang mempunyai kemainpuan beranak lebih dari dua ekor porkelahiran Metode vang digunakan dalam penelitian adalan metode survei di Kecamatan Singorojo Kabupaten Kendal dengan penentuan sampel secara porposif sedang analisis data inenggunakan uji t.test dan statistik diskriptif. Hasi! penelitian menunjukkan bahwa kambing yang dapat beranak lend' dari dua ekor tidak berbeda dengan kambing beranak lungs& maupun yang beranak kembar dua baik dari segi bobot badan, tinggi badan. panjang badan, Inbar dada, dalam dada, profil muka, bulu paha dan bentuk ambing. Tetapi dilihat ciri-ciri spesifiknya (profil muka, bulu paha dan bentuk ambing) dibandingkan dengan ciri-ciri spesifik kambing kacang maupun kambing peranakan ettawa (PE) dapat dikatakan berlainan, sebab yang menyamai kambing PE 3 ekor (11,54 %) menyamai ciri kambing kacang jenis kambing tersebut 2 ekor (3,85 %). Dan yang mempunyai ciri-ciri diantara kedua jenis kambing (kacang dan etawah) sebanyak 21 ekor (S4,61%) Yang terinci sebagai berikut : terbanyak acialah profil muka lurus, bull] palm banyak dan panjang sena ambing-puling berbentuk rnangkok mencapai 14 ekor (53,85 %) kemudian profil muka cembung, bulu paha panjang dan banyak serta ambing-puting bentuk mangkok 6 ekor (23,03 %). Muka cembung, bulu paha tidak berkembang, ambing-puting berbentuk mangkok I ekor (3,85%)

STUDI POTENSI REPRODUKSI KAMBING BERANAK LEBIll DARI DUA EKOR PER KELAHIRAN SEBAGAI DASAR PENMBENTUKAN KELOMPOK KAMBING BERANAK BANYAK

Research on kidding ability of ewes had been conducted at Singorojo, Kendal Resident. The aim of the research was to find out a maternal ability of ewes giving a birth more than two kids (n = 26 head). The sample was chosen by using purposive randomized sampling. Result showed that there was no significantly difference between sample and both single and twins, based on body weight. body height, body length, chest width, chest depth, facial profile, hip hair and udder shape. Characteristic of facial profile, hip hair and udder shape of sample found showed that there was difference between sample goats and both Kacang and Ettawah Crossbred Goats at 3 head (11,54%) and 2 head (3,85%), respectively. Moreover, the identification of sample related to facial profile was facial convex and facial straight at 14 head (53,85%) and 6 head (23,08%), respectively

Studi Potensi Reproduksi Kambing Beranak Lebih dari Dua Ekor per Kelahiran Sebagai Dasar Pembentukan Kelompok Kambing Beranak Banyak

penelitian ini bermaksud mengetahui potensi kambing-kambing yang mempunyai kemampuan beranak lebih dan dua ekor per kelahiran. Metode yang digunakan dalam penelitian adalah metode survei di Kecamatan Singorojo Kabupaten Kendal dengan penentuan sampel secara porposif sedang analisis data menggunakan uji t.test dan statistik diskriptif. Hasil penelitian menunjukkan bahwa kambing yang dapat beranak lebib dan dua ekor tidak berbeda dengan kambing beranak tunggal maupun yang beranak kembar dua baik dan segi bobot badan, tinggi badan, panjang badan, lebar dada. dalam dada, profil muka, bulu paha dan bentuk ambing. Research on kidding ability of ewes had been conducted at Singorojo, Kendal Resident. The aim of the research vas to find out a maternal ability of ewes giving a birth more than two kids (n = 26 head). The sample was chosen by using purposive randomized sampling. Result showed that there was no significantly difference between sample and both single and twins, based on body weight, body height, body . length, chest width, chest depth, facial profile, hip hair and udder shape. Characteristic of facial profile, hip hair and udder shape of sample found showed that there was difference between sample goats and both Kacang and Ettawah Crossbred Goat

Signal transduction pathways linking polyamines to apoptosis

Polyamines are important multifunctional cellular components and are classically considered as mediators of cell growth and division. Recently polyamines have been also implicated in cell death. Now it appears that polyamines are bivalent regulators of cellular functions, promoting proliferation or cell death depending on the cell type and on environmental signals. This review draws a picture about the role of polyamines in signalling pathways related to apoptotic cell death and the proposed molecular targets of these polycations at the level of the apoptotic cascade. Solid evidence indicates that polyamines may affect the mitochondrial and postmitochondrial phases of apoptosis, by modulating cytochrome c release from mitochondria and activation of caspases. Recently, polyamines have been also implicated in the regulation of the premitochondrial phase of apoptosis, during which upstream apoptotic signal transduction pathways are activated. The studies reviewed here suggest that polyamines may participate in loops involving interaction with signal transduction pathways and activation/expression of proteins that may control cell death or cell growth

Polyamine depletion in aging heart is caused by the impairment of adenylate cyclase system

IT J BIOCHE

Study on the role of endogenous polyamines in glucagon, isoproterenol or serum-mediated induction of tyrosine aminotransferase in cultured heart cells

In confluent and serum-starved embryonic heart cell cultures, the addition of serum (10%), glucagon (GLU, 0.1 μM) or isoproterenol (ISO, 10 μM), causes the onset of ornithine decarboxylase (ODC) activity, with a maximum after 5-6 hr. This is paralleled by polyamine accumulation and by the induction of TAT, which, in the case of GLU and ISO, exhibits maximal activity at 4-3hr respectively, followed by a net decline. Cyclic AMP (cAMP) also accumulates after exposure to GLU or ISO. However, under different conditions of ODC inhibition, serum fails to induce TAT, thus supporting a relevant role of cellular polyamines in serum action. Conversely, cAMP and TAT responses to GLU or ISO are markedly improved under prevention of polyamine accumulation, which also leads to a longer lasting TAT inducibility. The suggestion is made that polyamines are not required in the cAMP-dependent mechanism of TAT induction, but rather in the restoration of the basal activity of the enzyme. © 1988 Academic Press, Inc