Inducing late phase of infarct protection in skeletal muscle by remote preconditioning: efficacy and mechanism

We have previously demonstrated that remote ischemic preconditioning (IPC) by instigation of three cycles of 10-min occlusion/reperfusion in a hindlimb of the pig elicits an early phase of infarct protection in local and distant skeletal muscles subjected to 4 h of ischemia immediately after remote IPC. The aim of this project was to test our hypothesis that hindlimb remote IPC also induces a late phase of infarct protection in skeletal muscle and that K(ATP) channels play a pivotal role in the trigger and mediator mechanisms. We observed that pig bilateral latissimus dorsi (LD) muscle flaps sustained 46 +/- 2% infarction when subjected to 4 h of ischemia/48 h of reperfusion. The late phase of infarct protection appeared at 24 h and lasted up to 72 h after hindlimb remote IPC. The LD muscle infarction was reduced to 28 +/- 3, 26 +/- 1, 23 +/- 2, 24 +/- 2 and 24 +/- 4% at 24, 28, 36, 48 and 72 h after remote IPC, respectively (P < 0.05; n = 8). In subsequent studies, hindlimb remote IPC or intravenous injection of the sarcolemmal K(ATP) (sK(ATP)) channel opener P-1075 (2 microg/kg) at 24 h before 4 h of sustained ischemia (i.e., late preconditioning) reduced muscle infarction from 43 +/- 4% (ischemic control) to 24 +/- 2 and 19 +/- 3%, respectively (P < 0.05, n = 8). Intravenous injection of the sK(ATP) channel inhibitor HMR 1098 (6 mg/kg) or the nonspecific K(ATP) channel inhibitor glibenclamide (Glib; 1 mg/kg) at 10 min before remote IPC completely blocked the infarct- protective effect of remote IPC in LD muscle flaps subjected to 4 h of sustained ischemia at 24 h after remote IPC. Intravenous bolus injection of the mitochondrial K(ATP) (mK(ATP)) channel inhibitor 5-hydroxydecanoate (5-HD; 5 mg/kg) immediately before remote IPC and 30-min intravenous infusion of 5-HD (5 mg/kg) during remote IPC did not affect the infarct-protective effect of remote IPC in LD muscle flaps. However, intravenous Glib or 5-HD, but not HMR 1098, given 24 h after remote IPC completely blocked the late infarct-protective effect of remote IPC in LD muscle flaps. None of these drug treatments affected the infarct size of control LD muscle flaps. The late phase of infarct protection was associated with a higher (P < 0.05) muscle content of ATP at the end of 4 h of ischemia and 1.5 h of reperfusion and a lower (P < 0.05) neutrophilic activity at the end of 1.5 h of reperfusion compared with the time-matched control. In conclusion, these findings support our hypothesis that hindlimb remote IPC induces an uninterrupted long (48 h) late phase of infarct protection, and sK(ATP) and mK(ATP) channels play a central role in the trigger and mediator mechanism, respectively.     

MeTaDoR: a comprehensive resource for membrane targeting domains and their host proteins

MOTIVATION: Protein-lipid interactions play a central role in cellular signaling and membrane trafficking and at the core of these interactions are domains specialized in lipid binding and membrane targeting. Considering the importance of these domains, we have created MeTaDoR, a comprehensive resource dedicated to membrane targeting domains (MTDs). RESULT: MeTaDoR begins with a brief introduction about all the important MTDs including their subcellular localization and structural features. Sequences of all known MTDs are then provided in two formats: standard Prosite format and a parsed tab-delimited format that provides a manually curated classification into binding or non-binding. Structures of all MTDs and host proteins known so far are provided with links to PDB and Pfam databases. Membrane-binding orientation of these proteins, whether experimentally determined or proposed, is also provided with links to the appropriate literature. To facilitate molecular dynamics studies of these proteins, the force-field parameters for many non-standard lipids that commonly interact with these proteins are also provided. Finally, an online server for predicting membrane-binding proteins and a search function with various search fields are included. The resource is publicly available and will be updated on a regular basis.     

Identification of putative serum glycoprotein biomarkers for human lung adenocarcinoma by multilectin affinity chromatography and LC-MS/MS

Glycoproteins in human serum play fundamental roles in many biological processes, and also have clinical value as biomarkers for disease progression and treatment. In this study, we isolated glycoproteins from the sera of three healthy individuals and three lung adenocarcinoma patients using multilectin affinity chromatography. The recovered glycoproteins were subjected to treatment with peptide-N-glycosidase F (PNGase F) and in-gel digestion by trypsin. Tryptic peptides were analyzed by nano-LC coupled to ESI-MS/MS and the MS/MS spectra were processed by Bioworks 3.2 and an in-house bioinformatics tool, ProtAn. Approximately 90% of the proteins identified contained more than one potential glycosylation site. Comparison of the serum glycoproteome of healthy and adenocarcinoma individuals revealed 38 cancer-selective proteins. Among them, 60% have previously been reported as low abundance proteins in human sera. We identified several cancer-selective proteins that have been previously characterized as potential indicators of lung cancer in serum or plasma, including haptoglobin (HP), inter-alpha-trypsin inhibitor heavy chain 4 (ITI-H4), complement C3 precursor, and leucine-rich alpha-2-glycoprotein. In addition, plasma kallikrein (KLKB1) and inter-alpha-trypsin inhibitor heavy chain 3 (ITI-H3) were identified as being potentially elevated in the lung cancer group, and were validated by Western blot analysis. Furthermore, approximately 18 kDa plasma kallirein protein fragment was detected at high levels in 25 out of 28 adenocarcinoma patients, while one of the eight normal individuals showed moderate positive. The results suggest that KLKB1 represents a potential candidate serum biomarker of lung cancer.     

Deciphering the proteome of the in vivo diagnostic reagent "purified protein derivative" from Mycobacterium tuberculosis

Purified protein derivative (PPD) has served as a safe and effective diagnostic reagent for 60 years and is the only broadly available material to diagnose latent tuberculosis infections. This reagent is also used as a standard control for a number of in vitro immunological assays. Nevertheless, the molecular composition and specific products that contribute to the extraordinary immunological reactivity of PPD are poorly defined. Here, a proteomic approach was applied to elucidate the gene products in the U.S. Food and Drug Administration (FDA) standard PPD-S2. Many known Mycobacterium tuberculosis T-cell antigens were detected. Of significance, four heat shock proteins (HSPs) (GroES, GroEL2, HspX, and DnaK) dominated the composition of PPD. The chaperone activities and capacity of these proteins to influence immunological responses may explain the exquisite solubility and immunological potency of PPD. Spectral counting analysis of three separate PPD reagents revealed significant quantitative variances. Gross delayed-type hypersensitivity (DTH) responses in M. tuberculosis infected guinea pigs were comparable among these PPD preparations; however, detailed histopathology of the DTH lesions exposed unique differences, which may be explained by the variability observed in the presence and abundance of early secretory system (Esx) proteins. Variability in PPD reagents may explain differences in DTH responses reported among populations.     

Secretome analysis of ionizing radiation-induced senescent cancer cells reveals that secreted RKIP plays a critical role in neighboring cell migration

Cellular senescence is a physiological program of irreversible growth arrest that is considered to play an important role in tumor suppression. Recent studies demonstrated that senescent cells secrete multiple growth regulatory proteins that could alter the behavior of neighboring cells. In this study, we investigated the effect of secretory proteins from ionizing radiation (IR) induced senescent tumor cells on normal and tumor cells. Conditioned medium (CM) from IR-induced senescent MCF7 cells significantly increased cell proliferation, invasion, migration, and wound healing activity in MCF7 cells and HUVECs. Comparative proteomics analysis revealed 24 differentially secreted protein spots including Raf kinase inhibitor protein (RKIP), α-Enolase, AKAP9, and MARK4, and the findings were confirmed by Western blot analysis of IR-induced senescent cancer cells. We found that RKIP was secreted via the classical pathway, and the transfection of small interfering RNA against RKIP suppressed CM-induced migration in MCF7 cells. Treatment with recombinant human RKIP increased the migratory activity of MCF7 cells. Taken together, our results demonstrate that the senescence-associated secretory protein RKIP could be the principal target to prevent the potential effects of the secretome from IR-induced senescent tumor cells on neighboring cell migration.     

Early Gestational Weight Gain Rate and Adverse Pregnancy Outcomes in Korean Women

During pregnancy, many women gain excessive weight, which is related to adverse maternal and neonatal outcomes. In this study, we evaluated whether rate of gestational weight gain (RGWG) in early, mid, and late pregnancy is strongly associated with adverse pregnancy outcomes. A retrospective chart review of 2,789 pregnant Korean women was performed. Weights were recorded at the first clinic visit, during the screening test for fetal anomaly, and during the 50g oral glucose challenge test and delivery, to represent early, mid, and late pregnancy, respectively. A multivariate logistic regression analysis was performed to examine the relationship between RGWG and adverse pregnancy outcomes. At early pregnancy, the RGWG was significantly associated with high risk of developing gestational diabetes mellitus (GDM), pregnancy-induced hypertension (PIH), large for gestational age (LGA) infants, macrosomia, and primary cesarean section (P-CS). The RGWG of mid pregnancy was not significantly associated with any adverse pregnancy outcomes. The RGWG at late pregnancy was significantly associated with a lower risk of developing GDM, preterm birth and P-CS, but with a higher risk of developing LGA infants and macrosomia. When the subjects were divided into three groups (Underweight, Normal, and Obese), based on pre-pregnancy body mass index (BMI), the relationship between early RGWG and adverse pregnancy outcomes was significantly different across the three BMI groups. At early pregnancy, RGWG was not significantly associated to adverse pregnancy outcomes for subjects in the Underweight group. In the Normal group, however, early RGWG was significantly associated with GDM, PIH, LGA infants, macrosomia, P-CS, and small for gestational weight (SGA) infants, whereas early RGWG was significantly associated with only a high risk of PIH in the Obese group. The results of our study suggest that early RGWG is significantly associated with various adverse pregnancy outcomes and that proper preemptive management of early weight gain, particularly in pregnant women with a normal or obese pre-pregnancy BMI, is necessary to reduce the risk of developing adverse pregnancy outcomes.     

Production of inulooligosaccharides from chicory extract by endoinulinase from Xanthomonas oryzae No. 5

Inulooligosaccharides (IOS) production from chicory extract was carried out using endoinulinase obtained from a new isolate, Xanthomonas oryzae No. 5. The IOS production from chicory extract was maximum when 50 g/liter of chicory extract was utilized as the substrate. As the substrate concentration increased, the IOS production accordingly decreased probably due to substrate inhibition. For a comparative study, enzyme reactions were carried out from pure inulin as substrate. Though total IOS contents indicated higher IOS yield with pure inulin compared to that of chicory extract, the distribution of inulooligosaccharide components between pure inulin and chicory extract was not significantly different; i.e. DP5 and higher oligosaccharides are major products in case of both chicory extract and pure inulin as substrate. A considerable amount of oligofructose (about 30%, w/w), which were originally present in chicory extract, resulted in the change of the enzyme kinetics. A reaction pH 7 was found to be most suitable for enzyme reaction. The initial reaction rates increased with increasing enzyme dosage, although the relative composition of the IOS produced remain unchanged.     

Comparing contributions of soil versus root colonization to variations in stomatal behavior and soil drying in mycorrhizal Sorghum bicolor and Cucurbita pepo

In prior studies we learned that colonization of soil can be as important as colonization of roots in determining mycorrhizal influence on the water relations of host plants. Here we use a path analysis modeling approach to test (a) whether quantity of hyphae in soil contributes to variations in stomatal behavior and soil drying, and (b) whether soil colonization or root colonization has a stronger influence on these stomatal and soil drying responses. Experiments were performed on Sorghum bicolor and Cucurbita pepo, with soils and roots colonized by a mixture of Glomus intraradices and Gigaspora margarita. Soil colonization generally made more significant contributions to stomatal conductance than did root colonization. Soil colonization did not make significant direct contributions to soil water potential measures (soil water potential at stomatal closure or soil drying rate), whereas root colonization did contribute a potentially important path to each. The findings further support a role for mycorrhization of the soil itself in contributing to the regulation of stomatal behavior of host plants.     

Production of genetically modified pigs expressing human insulin and C-peptide as a source of islets for xenotransplantation

Transgenic Research - Islet xenotransplantation is a promising treatment for type I diabetes. Numerous studies of islet xenotransplantation have used pig-to-nonhuman primate transplantation models....