The lack of a clonal renin-secreting cell line has greatly hindered the investigation of the regulatory mechanisms of renin secretion at the cellular, biochemical, and molecular levels. In the present study, we investigated whether it was possible to induce phenotypic switching of the renin-expressing clonal cell line As4.1 from constitutive inactive renin secretion to regulated active renin secretion. When grown to postconfluence for at least two days in media containing fetal bovine serum or insulin-like growth factor-1, the formation of cell-cell contacts via N-cadherin triggered downstream cellular signaling cascades and activated smooth muscle-specific genes, culminating in phenotypic switching to a regulated active renin secretion phenotype, including responding to the key stimuli of active renin secretion. With the use of phenotype-switched As4.1 cells, we provide the first evidence that active renin secretion via exocytosis is regulated by phosphorylation/dephosphorylation of the 20 kDa myosin light chain. The molecular mechanism of phenotypic switching in As4.1 cells described here could serve as a working model for full phenotypic modulation of other secretory cell lines with incomplete phenotypes.

No abstract available.
Education* ; Humans ; Licensure* ; Physical Therapists*

Recent studies have documented that Janus-activated kinase (JAK)-signal transducer and activator of transcription (STAT) pathway can modulate the apoptotic program in a myocardial ischemia/reperfusion (I/R) model. To date, however, limited studies have examined the role of JAK3 on myocardial I/R injury. Here, we investigated the potential effects of pharmacological JAK3 inhibition with JANEX-1 in a myocardial I/R model. Mice were subjected to 45 min of ischemia followed by varying periods of reperfusion. JANEX-1 was injected 1 h before ischemia by intraperitoneal injection. Treatment with JANEX-1 significantly decreased plasma creatine kinase and lactate dehydrogenase activities, reduced infarct size, reversed I/R-induced functional deterioration of the myocardium and reduced myocardial apoptosis. Histological analysis revealed an increase in neutrophil and macrophage infiltration within the infarcted area, which was markedly reduced by JANEX-1 treatment. In parallel, in in vitro studies where neutrophils and macrophages were treated with JANEX-1 or isolated from JAK3 knockout mice, there was an impairment in the migration potential toward interleukin-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1), respectively. Of note, however, JANEX-1 did not affect the expression of IL-8 and MCP-1 in the myocardium. The pharmacological inhibition of JAK3 might represent an effective approach to reduce inflammation-mediated apoptotic damage initiated by myocardial I/R injury.
Animals ; Apoptosis/drug effects ; Cell Movement/drug effects ; Chemokines/pharmacology ; Heart Function Tests/drug effects ; Inflammation/pathology ; Janus Kinase 3/*antagonists & inhibitors/metabolism ; Macrophages/drug effects/metabolism/pathology ; Male ; Mice ; Mice, Inbred C57BL ; Myocardial Reperfusion Injury/drug therapy/*enzymology/physiopathology/*prevention & control ; Myocardium/enzymology/pathology ; Myocytes, Cardiac/drug effects/metabolism/pathology ; Neutrophils/drug effects/metabolism/pathology ; Quinazolines/pharmacology/therapeutic use

The role of the kidney in combating metabolic acidosis has been a subject of considerable interest for many years. The present study was aimed to determine whether there is an altered regulation of renal acid base transporters in acute and chronic acid loading. Male Sprague-Dawley rats were used. Metabolic acidosis was induced by administration of NH4Cl for 2 days (acute) and for 7days (chronic). The serum and urinary pH and bicarbonate were measured. The protein expression of renal acid base transporters [type 3 Na+/H+ exchanger (NHE3), type 1 Na+/HCO3- cotransporter (NBC1), Na-K+ ATPase, H(+)-ATPase, anion exchanger-1 (AE-1)] was measured by semiquantitative immunoblotting. Serum bicarbonate and pH were decreased in acute acid loading rats compared with controls. Accordingly, urinary pH decreased. The protein expression of NHE3, H(+)-ATPase, AE-1 and NBC1 was not changed. In chronic acid loading rats, serum bicarbonate and pH were not changed, while urinary pH was decreased compared with controls. The protein expression of NHE3, H(+)-ATPase was increased in the renal cortex of chronic acid loading rats. These results suggest that unaltered expression of acid transporters combined with acute acid loading may contribute to the development of acidosis. The subsequent increased expression of NHE3, H(+)-ATPase in the kidney may play a role in promoting acid excretion in the later stage of acid loading, which counteract the development of metabolic acidosis.
Acidosis ; Adenosine Triphosphatases ; Ammonium Chloride ; Animals ; Humans ; Hydrogen-Ion Concentration ; Immunoblotting ; Kidney ; Male ; Proton-Translocating ATPases ; Quaternary Ammonium Compounds ; Rats ; Rats, Sprague-Dawley ; Sodium-Hydrogen Antiporter

Gap junction protein, connexin, is expressed in endothelial cells of vessels, glomerulus, and renin secreting cells of the kidney. The purpose of this study was to investigate the role of gap junction in renin secretion and its underlying mechanisms using As 4.1 cell line, a renin-expressing clonal cell line. Renin release was increased proportionately to incubation time. The specific gap junction inhibitor, 18-beta glycyrrhetinic acid (GA) increased renin release in dose-dependent and time- dependent manners. Heptanol and octanol, gap junction blockers, also increased renin release, which were less potent than GA. GA-stimulated renin release was attenuated by pretreatment of the cells with amiloride, nifedipine, ryanodine, and thapsigargin. GA dose-dependently increased intracellular Ca2+ concentration, which was attenuated by nifedipine, nimodipine, ryanodine, and thapsigargin. However, RP-cAMP, chelerythrine, tyrphostin A23, or phenylarsine oxide did not induced any significant change in GA-stimulated increase of intracellular Ca2+ concentration. These results suggest that gap junction plays an important role on the regulation of renin release and intracellular Ca2+ concentration in As 4.1 cells.
Amiloride ; Calcium* ; Cell Line* ; Connexins ; Endothelial Cells ; Gap Junctions* ; Glycyrrhetinic Acid ; Heptanol ; Kidney ; Nifedipine ; Nimodipine ; Renin* ; Ryanodine ; Thapsigargin

One case of ovarian pregnancy. Ovarian Pregnacy is a rare form of ectopic pregnancy. Its estimated overall incidence is highly variable. Ovarian pregnancy occurs in the corpus luteum mostly, and is usually accompanied with the rupture of the ovary and massive hemoperitoneum. It presents as a hemorrhagic ovary and frequently misdiagnosed as a ruptured corpus luteum. Risk factors to ovarian pregnancy include a history of pelvic inflammatory disease (PID), prior pelvic surgery, use of an intrauterine contraceptive device (IUD) and ovulation induction. We have experienced one case of ovarian pregnancy and reviewed it briefly.
Corpus Luteum ; Female ; Hemoperitoneum ; Incidence ; Intrauterine Devices ; Ovary ; Ovulation Induction ; Pelvic Inflammatory Disease ; Pregnancy ; Pregnancy, Ectopic* ; Risk Factors ; Rupture

It is well known that tumor necrosis factor (TNF-a), interleukin-1, platelet-activating factor (PAF) and arachidonic acid metabolites, such as thromboxane and leukotriens, are major mediators involved in the pathogenesis of endotoxic shock. In this study, we have investigated the effect of pentoxifylline (inhibitor of TNF-a release), BN50739 (PAF antagonist), indomethacin (cyclooxygenase inhibitor) and diethylcarbamazine (lipoxygenase inhibitor) on LPS- induced lethality as well as the relationship between major mediators in endotoxic shock. All inhibitors described above except diethylcarbamazine significantly protected mice against LPS- induced lethality. BN50739 and indomethacin were also effective in protection of TNF-a-induced lethality. The elevation of circulating TNF-a by LPS was significantly blocked by BN50739, but not affected by indomethacin. Convulsion appeared shortly after LPS injection was prevented by BN50739 but not by indomethacin, whereas diarrhea and limited movement was prevented by indomethacin but not by BN50739. These results indicate that i) TNF-a, PAF and cyclooxygenase products are important mediators involved in the pathogenesis of septic shock and ii) TNF-a directly influenced the release or production of PAF as well as cyclooxygenase products, and strongly suggest that i) TNF-a and PAF stimulate the release of each other via positive feedback network but TNF-a and cyclooxygenase products do not form the network and ii) PAF and cyclooxygenase product appear not to affect the release of each other.
Animals ; Arachidonic Acid ; Diarrhea ; Diethylcarbamazine ; Gene Expression* ; Indomethacin ; Interleukin-1 ; Mice ; Pentoxifylline ; Prostaglandin-Endoperoxide Synthases ; Seizures ; Shock, Septic ; Tumor Necrosis Factor-alpha*

The ultraviolet radiation (UVR) is known to be a potent modulator of many host immune functions and the exposure of experimental animals to the inflammatory effects of UVR induces depressions in their ability to initiate and effectuate various types of cellular immune responses. In this study, the effects of UV-B (280 320 nm) radiation on resistance to a facultative intracellular bacterium, Listeria monocytogenes (LM), were examined at the cellular level. The numbers of cultivable LM recovered from the spleens of UV-B-irradiated mice were decreased at 2 days postinfection compared with those of untreated control mice. However, the acquired immunity, developed 7 days after immunization with streptomycin (SM)-sensitive LM, in either UV-irradiated, LPS- or IL-1-pretreated mice was less stronger than that developed in untreated, control mice. To elucidate the possible mechanisms underlying the observation that UVR did increase innate immunity but decreased acquired immunity of mice to the infection with LM, the effects of UVR of mice on the production of IFN-r by activated splenocytes and TNF-a by peritoneal macrophages were assessed. Activated splenocytes from UV-irradiated mice exhibited a reduced capacity to produce IFN-r and cultured peritoneal macrophages produced more TNF-a in the presence of LPS during 24 hours after UV radiation. Though TNF-r activity was not detected in the sera of LM-infected mice, intravenous LPS injection induced TNF-r production and UVR decreased TNF activity in sera obtained from LM-infected mice with LPS induction 9 days after irradiation. Although Ia-negative macrophages were predominant in the peritoneal macrophages from untreated control mice, the infection of mice with LM caused a marked increase in Ia expression on peritoneal macrophages. However, UVR resulted in decreased expression of Ia molecule on the peritoneal macrophages during the LM infection. These findings suggest that the dual effects of UVR on the innate and acquired immunity of mice to the LM infection may be associated with altered capacities of splenocytes and peritoneal macrophages of the mice to produce cytokines, in addition to decrease of la molecule expression on the macrophages.
Adaptive Immunity ; Animals ; Cytokines ; Depression ; Immunity, Cellular ; Immunity, Innate ; Immunization ; Listeria monocytogenes* ; Listeria* ; Macrophages ; Macrophages, Peritoneal ; Mice* ; Spleen ; Streptomycin ; Tumor Necrosis Factor-alpha*

No abstract available.
Angiotensin I ; Angiotensin II* ; Angiotensins* ; Autoradiography ; Receptors, Angiotensin* ; Renin* ; Renin-Angiotensin System*

No abstract available.
Angiotensin I ; Angiotensin II* ; Angiotensins* ; Autoradiography ; Receptors, Angiotensin* ; Renin* ; Renin-Angiotensin System*