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Hexokinase-3 (HK3) is a member of hexokinase family, which can catalyze the first step of glucose metabolism. It can increase ATP levels, reduce the production of reactive oxygen species, increase mitochondrial biogenesis, protect mitochondrial membrane potential and play an antioxidant role. However, the change of its expression in spinal cord after injury is still unknown. In this study, we investigated the spatio-temporal expression of HK3 in the spinal cords by using a spinal cord injury (SCI) model in adult female Sprague-Dawley rats. Quantitative reverse transcription-PCR and western blot analysis revealed that HK3 could be detected in sham-opened spinal cords. After SCI, it gradually increased, reached a peak at 7 days post-injury (dpi), and then gradually decreased with the prolonging of injury time, but still maintained at a higher level for up to 28 dpi (the longest time evaluated in this study). Immunofluorescence staining showed that HK3 was found in GFAP + , β-tubulin III + and IBA-1 + cells in sham-opened spinal cords. After SCI, in addition to the above-mentioned cells, it could also be found in CD45 + and CD68 + cells. These results demonstrate that HK3 is mainly expressed in astrocytes, neurons and microglia in normal spinal cords, and could rapidly increase in infiltrated leukocytes, activated microglia/macrophages and astrocytes after SCI. These data suggest that HK3 may be involved in the pathologic process of SCI by promoting glucose metabolism. [ABSTRACT FROM AUTHOR]

Previous studies have shown that Apelin-13 upregulates early growth response factor-1 (Egr-1) via the extracellular signal-regulated protein kinase (ERK) signaling pathway. Apelin-13 induces proliferation and migration of vascular smooth muscle cells (VSMCs) as well as the upregulation of osteopontin (OPN) via the upregulation of Egr-1. This study was designed to further explore the activity of Apelin-13 in VSMCs by investigating members of the mitogen-activated protein kinase (MAPK) family, in particular Jun kinase (JNK) and p38 mitogen-activated protein kinase (P38). We also examined whether the phosphatidylinositol 3 kinase (PI3K)/protein kinase B (Akt) and protein kinase C (PKC) signaling pathways were involved in the regulation of Egr-1 by Apelin-13. We treated rat aortic VSMCs with Apelin-13 and examined the expression of JNK, p-JNK, P38, and p-P38 to investigate whether Apelin-13-mediated increases in Egr-1 occurred through the JNK and P38 signaling pathways. We then pretreated VSMCs with the Gi protein inhibitor pertussis toxin (PTX) and the Gq inhibitor YM254890, added Apelin-13 and looked for changes in Egr-1 expression. Finally, we pretreated with the PI3K inhibitor LY294002 and the PKC inhibitor GF109203X, and treated with Apelin-13. Our results showed that JNK and P38 did not participate in Apelin-13-mediated increase in Egr-1. Instead, Apelin-13 upregulation of Egr-1 was mediated by a PTX-sensitive Gi protein. Apelin-13 did increase ERK phosphorylation through the PI3K/Akt and PKC signaling pathways, resulting in changes in Egr-1 expression. These data provide important targets for future studies to modulate vascular remodeling. [ABSTRACT FROM AUTHOR]

Abstract: Diabetic Retinopathy (DR) is one of the most common complications of diabetes and a major cause of blindness worldwide. We studied the transcriptome of the diabetic retina using Series Analysis of Gene Expression (SAGE) technology and observed a 45.6% reduction in transcript levels of glutamine synthetase (GS) in streptozotocin-induced diabetic rats compared with normal rats. RT-PCR and colorimetric enzyme activity assays revealed significant differences in GS mRNA expression and enzyme activity as early as the first month of diabetes development, with a progressive decrease in GS mRNA level and enzyme activity over a 12-month period. Northern blot analysis indicated a linear correlation between the reduction in GS expression and the time course of diabetic retinopathy (r = 0.802, p < 0.0001), which was validated by real-time RT-PCR (r = 0.731, p < 0.001). Our results implicate GS as a possible biomarker for evaluating the severity of developed diabetic retinopathy over the time course of diabetes progression. [Copyright &y& Elsevier]

Background: Prenatal dexamethasone exposure has been reported to increase allergy potential in childhood possibly by interference with normal immunological development in utero. This study investigated the effects of prenatal dexamethasone on T helper cell immune responses in a rat model. Methods: Pregnant rats received either dexamethasone 0.1 mg/kg/day or normal saline from gestational day 14–21. Off-springs were cared for by their biological mother, or cross-fostered by the opposing group. Spleen and blood samples were collected at post-natal day 7 and 120 and tested for mRNA expression and plasma cytokine levels of Th1/Th2/Th17 immune response. Results: Both Th1 (T-bet) and Th2 (GATA-3) mRNA expression were shown to have a significant increase in the prenatal dexamethasone exposure group at day 120 (p<0.05). The plasma levels for Th1 (IFNγ and IL-2) and Th2 (IL-4, IL-5, IL-13) were found to have no significant differences between the two group (p>0.05). The mRNA expression of Th17 (RORγt) showed a significant decrease at post-natal day 120 as well as the plasma level of IL-17A at day 7 (11.21±1.67 vs. 6.23±1.06 pg/ml, p = 0.02). Cross-fostering by a dexamethasone exposed mother resulted in a significant increase in Th1/Th2 mRNA expression (p<0.05) and decrease of Th17. Conclusions: Prenatal dexamethasone exposure increased Th1, Th2 and decreased Th17 expression. Cross-fostering by a dexamethasone exposed mother results in more prominent increase of Th1 and Th2 expression. [ABSTRACT FROM AUTHOR]

Adiponectin and adiponectin receptors (AdipoR1/2) are expressed in various tissues and are involved in the regulation of multiple functions such as energy metabolism and inflammatory responses. However, the effect of adiponectin and AdipoRs in submandibular glands has not been fully evaluated. In the present study, we found that mRNA and protein of both adiponectin and AdipoR1/2 were expressed in rat submandibular glands and in the SMG-C6 cell line, as evidenced by RT-PCR and Western blot analysis. Immunofluorescence staining showed that adiponectin was diffused in the cytoplasm, while AdipoR1/2 was concentrated in the membrane of acinar cells. Saliva flow was significantly increased by full length adiponectin (fAd) or globular adiponectin (gAd) perfusion in isolated rat submandibular glands. 5-Aminoimidazole-4-carboxamide-1-4-ribofuranoside (AICAR), an adenosine monophosphate activated protein kinase (AMPK) activator, also increased saliva secretion. fAd, gAd, and AICAR all increased the average width of apical tight junctions in perfused submandibular glands, and decreased transepithelial electrical resistance (TER) in SMG-C6 cells, suggesting that adiponectin promoted secretion by modulating paracellular permeability. fAd and gAd increased p-AMPK levels, while AraA, an AMPK antagonist, abolished fAd- and gAd-induced changes in secretion, tight junction ultrastructure, and TER. Moreover, both AdipoR1 and AdipoR2 were required for fAd- or gAd-induced p-AMPK and TER responses, suggesting from their inhibition following AdipoR1 or AdipoR2 knockdown, and co-knockdown of AdipoRs by RNA interference. Our results suggest that adiponectin functions as a promoter of salivary secretion in rat submandibular glands via activation of AdipoRs, AMPK, and paracellular permeability. [ABSTRACT FROM AUTHOR]

Abstract: We previously reported that exogenous H2S played roles in protection of respiratory centers against hypoxic injury in medullary slices of neonatal rats. The protective action of endogenous H2S and its relation to antioxidation and down-regulation of c-fos mRNA were investigated in the present study. Perfusion of the slices with l-cysteine (Cys), substrate of cystathionine β-synthase (CBS, H2S synthase), could increase frequency of rhythmic respiratory discharge of the hypoglossal rootlets and prevent respiratory suppression induced by hypoxia, whereas perfusion with hydroxylamine (NH2OH, inhibitor of CBS) could postpone recovery of respiration from hypoxic inhibition. NH2OH also significantly enhanced hypoxia-induced increase in malondialdehyde (MDA) content of the slices. The hypoxia-induced up-regulation of c-fos mRNA could be markedly antagonized by S-adenosyl-l-methionine (SAM, activator of CBS), but greatly increased by NH2OH. Neither NH2OH, Cys nor SAM had any effect on expression of bcl-2 mRNA in hypoxic medullary slices. These results indicate that endogenously generated H2S was involved in protection of the medullary respiratory centers against hypoxic injury partly via antioxidation and down-regulation of c-fos. [Copyright &y& Elsevier]

Abstract: Hydrogen sulfide (H2S) has been shown to play a protective role in injury of cells induced by hypoxia. Little is known however about its effect on medullary hypoxia-induced rhythmic respiratory suppression. In the present study, a decrease in frequency of rhythmic discharge of hypoglossal rootlets was observed in medullary slices of neonatal rats perfused with 95% N2–5% CO2 to produce hypoxia. Perfusion with NaHS (H2S donor) prevented the inhibitory effect of hypoxia on the burst activity of the rootlets, whereas such action of NaHS was suppressed by pretreatment with glibenclamide, a blocker of KATP channels. In addition, the increase in malondialdehyde content and the up-regulation of c-fos mRNA expression of the slices induced by hypoxia was significantly reduced by NaHS. These results indicate that exogenous H2S may protect the medullary respiratory center against hypoxic injury via activation of KATP channels, reduction of lipid peroxidation and down-regulation of c-fos. [Copyright &y& Elsevier]

Abstract: It is well known that fibroblasts can act as a cell vector to express functional protein, like neurotrophin-4 (NT-4). The present study evaluated the effect of NT-4 gene modified fibroblasts grafted into the hippocampus of AD rat model. AD rats were reproduced by bilateral transection of the hippocampal fimbria-fornix. The transplanted fibroblasts steadily expressed NT-4 proteins at least 2 months after transplantation. This correlated with a significant rescue in the number of cholinergic neurons in the host hippocampus. Morris water maze tests demonstrated significant improvements in learning and memory, especially in rats receiving NT-4-modified fibroblasts. The present results showed that NT-4 gene modified fibroblasts could provide a long-term and steady expression of NT-4, and it significantly improved the behavior of AD rats. These findings should have important clinical applications in providing a long-term NT-4 Secretion for the treatment of AD. [Copyright &y& Elsevier]