Myristoylated alanine-rich C kinase substrate (MARCKS) is a widely distributed protein kinase C (PKC) substrate and has been implicated in actin cytoskeletal rearrangement in response to extracellular stimuli. Although MARCKS was extensively examined in various cell culture systems, the physiological function of MARCKS in the central nervous system has not been clearly understood. We investigated alterations of cellular distribution and phosphorylation of MARCKS in the hippocampus following kainic acid (KA)-induced seizures. KA (25 mg/kg, i.p.) was administered to eight to nine week-old C57BL/6 mice. Behavioral seizure activity was observed for 2 h after the onset of seizures and was terminated with diazepam (8 mg/kg, i.p.). The animals were sacrificed and analyzed at various points in time after the initiation of seizure activity. Using double-labeling immunofluorescence analysis, we demonstrated that the expression and phosphorylation of MARCKS was dramatically upregulated specifically in microglial cells after KA-induced seizures, but not in other types of glial cells. PKC alpha, beta I, beta II and delta, from various PKC isoforms examined, also were markedly upregulated, specifically in microglial cells. Moreover, immunoreactivities of phosphorylated MARCKS were co-localized in the activated microglia with those of the above isoforms of PKC. Taken together, our in vivo data suggest that MARCKS is closely linked to microglial activation processes, which are important in pathological conditions, such as neuroinflammation and neurodegeneration.
Up-Regulation/drug effects ; Time Factors ; Seizures/chemically induced/*metabolism ; Protein Kinase C-delta/analysis ; Protein Kinase C-alpha/analysis ; Protein Kinase C/*analysis ; Protein Biosynthesis/drug effects ; Phosphorylation/drug effects ; Microscopy, Confocal ; Microglia/cytology/drug effects/*metabolism ; Mice, Inbred C57BL ; Mice ; Membrane Proteins/*analysis/metabolism ; Kainic Acid/*toxicity ; Isoenzymes/analysis ; Intracellular Signaling Peptides and Proteins/*analysis/metabolism ; Immunohistochemistry ; Animals

BACKGROUNDAirway smooth muscle (ASM) is suspected to be a determining factor in the structural change of asthma. However, the role of protein kinase C alpha (PKCalpha) and cyclin D1 involved in the dysfunction of ASM leading to asthmatic symptoms is not clear. In this study, the central role of PKCalpha and cyclin D1 in ASM proliferation in asthmatic rats was explored.

METHODSThirty-six pathogen-free male Brown Norway (BN) rats were randomly divided into 2 groups: control groups (group N1, N2 and N3) and asthmatic groups (group A1, A2, and A3). Groups A1, A2 and A3 were challenged with ovalbumin (OA) for 2 weeks, 4 weeks and 8 weeks respectively. Control animals were exposed to an aerosolized sterile phosphate buffered saline (PBS). The ASM mass and nucleus numbers were studied to estimate the degree of airway remodeling by the hematoxylin-eosin staining method. PKCalpha and cyclin D1 expression in the ASM cells was detected by reverse transcription polymerase chain reaction (RT-PCR) and immunohistochemistry. The relation between PKCalpha and cyclin D1 was assessed by linear regression analysis. PKC agonist phorbol 12-myristate 13-acetate (PMA), PKC inhibitor Ro31-8220 and an antisense oligonucleotide against cyclin D1 (ASOND) were used to treat ASM cells (ASMCs) obtained from the 2 weeks asthmatic rats. The cyclin D1 protein expression level was detected by Western blotting.

RESULTSCompared with the control group, the PKCalpha and cyclin D1 mRNA levels were increased in the asthmatic group. Similar to RT-PCR results, immunohistochemistry analysis for PKCalpha and cyclin D1 expression revealed an increased production in ASMCs after allergen treatment for 2, 4 and 8 weeks compared with the respective control groups. No difference in expression of PKCalpha and cyclin D1 in ASM were found in the 2, 4 or 8 weeks asthmatic rats. There were significant positive correlations between PKCalpha and cyclin D1 expression, both transcriptionally (r = 0.944, P < 0.01) and translationally (r = 0.826, P < 0.01), in ASM. The content of cyclin D1 in asthmatic ASMCs increased after being stimulated by PMA, and decreased when induced by Ro31-8220. ASOND targeting for cyclin D1 lowered the expression of cyclin D1 induced by PMA.

CONCLUSIONSIncreased expression of PKCalpha and cyclin D1 in ASM along with smooth muscle structure changes might implicate PKCalpha and cyclin D1 participation in the proliferation of ASM and contribute to the pathogenesis of asthma after repeated allergen exposure in rats. The results suggested that cyclin D1 might be downstream of PKC signal transduction pathway.

Animals ; Asthma ; pathology ; Cell Proliferation ; Cyclin D1 ; genetics ; physiology ; Lung ; pathology ; Male ; Myocytes, Smooth Muscle ; pathology ; Protein Kinase C-alpha ; genetics ; physiology ; RNA, Messenger ; analysis ; Rats ; Rats, Inbred BN

Pulmonary dysfunction caused by ischemia-reperfusion injury is the leading cause of mortality in lung transplantation. We aimed to investigate the effects of sevoflurane pretreatment on lung permeability, tight junction protein occludin and zona occludens 1 (ZO-1) expression, and translocation of protein kinase C (PKC)-alpha after ischemia-reperfusion. A lung ischemia-reperfusion injury model was established in 96 male Wistar rats following the modified Eppinger method. The rats were divided into four groups with 24 rats in each group: a control (group C), an ischemia-reperfusion group (IR group), a sevoflurane control group (sev-C group), and a sevoflurane ischemia-reperfusion group (sev-IR group). There were three time points in each group: ischemic occlusion for 45 min, reperfusion for 60 min and reperfusion for 120 min; and there were six rats per time point. For the 120-min reperfusion group, six extra rats underwent bronchoalveolar lavage. Mean arterial pressure (MAP) and pulse oxygen saturation (SpO2) were recorded at each time point. The wet/dry weight ratio and lung permeability index (LPI) were measured. Quantitative RT-PCR and Western blot were used to measure pulmonary occludin and ZO-1, and Western blot was used to measure cytosolic and membranous PKC-alpha in the lung. Lung permeability was significantly increased after ischemia-reperfusion. Sevoflurane pretreatment promoted pulmonary expression of occludin and ZO-1 after reperfusion and inhibited the translocation of PKC-alpha. In conclusion, sevoflurane pretreatment alleviated lung permeability by upregulating occludin and ZO-1 after ischemia-reperfusion. Sevoflurane pretreatment inhibited the translocation and activation of PKC-alpha, which also contributed to the lung-protective effect of sevoflurane.
Anesthetics, Inhalation/*therapeutic use ; Animals ; Capillary Permeability/drug effects ; Gene Expression Regulation/drug effects ; Lung/*drug effects/metabolism/pathology ; Lung Diseases/*drug therapy/genetics/metabolism/pathology ; Male ; Methyl Ethers/*therapeutic use ; Protein Kinase C-alpha/*metabolism ; Protein Transport/drug effects ; RNA, Messenger/genetics ; Rats, Wistar ; Reperfusion Injury/*drug therapy/genetics/metabolism/pathology ; Zonula Occludens-1 Protein/analysis/*genetics

In women with preeclampsia (PE), endothelial cell (EC) dysfunction can lead to altered secretion of paracrine factors that induce peripheral vasoconstriction and proteinuria. This study examined the hypothesis that PE sera may directly or indirectly, through human umbilical vein ECs (HUVECs), stimulate phospholipase C-gamma1-1,4,5-trisphosphate (PLC-gamma1-IP3) signaling, thereby increasing protein kinase C-alpha (PKC-alpha) activity, collagen I expression and intracellular Ca2+ concentrations ([Ca2+]i) in human umbilical artery smooth muscle cells (HUASMCs). HUASMCs and HUVECs were cocultured with normal or PE sera before PLC-gamma1 silencing. Increased PLC-gamma1 and IP3 receptor (IP3R) phosphorylation was observed in cocultured HUASMCs stimulated with PE sera (P<0.05). In addition, PE serum significantly increased HUASMC viability and reduced their apoptosis (P<0.05); these effects were abrogated with PLC-gamma1 silencing. Compared with normal sera, PE sera increased [Ca2+]i in cocultured HUASMCs (P<0.05), which was inhibited by PLC-gamma1 and IP3R silencing. Finally, PE sera-induced PKC-alpha activity and collagen I expression was inhibited by PLC-gamma1 small interfering RNA (siRNA) (P<0.05). These results suggest that vasoactive substances in the PE serum may induce deposition in the extracellular matrix through the activation of PLC-gamma1, which may in turn result in thickening and hardening of the placental vascular wall, placental blood supply shortage, fetal hypoxia-ischemia and intrauterine growth retardation or intrauterine fetal death. PE sera increased [Ca2+]i and induced PKC-alpha activation and collagen I expression in cocultured HUASMCs via the PLC-gamma1 pathway.
Adult ; Apoptosis ; Calcium/*metabolism ; Cell Line ; Cell Survival ; Cells, Cultured ; Coculture Techniques ; Collagen Type I/analysis/*metabolism ; Female ; Human Umbilical Vein Endothelial Cells ; Humans ; Muscle, Smooth, Vascular/*cytology/metabolism ; Phospholipase C gamma/genetics/*metabolism ; Pre-Eclampsia/*blood/*metabolism/pathology ; Pregnancy ; Protein Kinase C-alpha/metabolism ; RNA Interference ; *Signal Transduction ; Young Adult

Alcohol influences the neuroadaptation of brain cells where receptors and enzymes like protein kinase C (PKC) exist. Naltrexone acts on opioid receptors. However, other mechanisms of action remain unknown. We prepared SH-SY5Y neuroblastoma cells, and fed them with 150 mM ethanol for 72 h followed by treatment with naltrexone for 24 h. We performed microarray analysis and reverse transcriptase-polymerase chain reaction. Our results showed that PKC epsilon increased 1.90 times and showed an overall decreasing pattern as time increased. Phosphorylated ERK also increased 2.0 times according to the change of PKC epsilon. Integrin alpha7 increased 2.32 times and showed an increasing pattern as time increased. In conclusion, naltrexone influences PKC epsilon neuronal signaling system and endothelial adhesion molecule integrin alpha7 in addition to the well-known opioid system.
Antigens, CD/*metabolism ; Cell Line, Tumor ; Comparative Study ; DNA, Complementary/genetics ; Humans ; Integrin alpha Chains/*metabolism ; Naltrexone/*pharmacology ; *Neuroblastoma/enzymology/metabolism/pathology ; Oligonucleotide Array Sequence Analysis ; Protein Kinase C-epsilon/*metabolism ; Research Support, Non-U.S. Gov't ; Reverse Transcriptase Polymerase Chain Reaction ; Time Factors