Μεσαίες πόλεις : προοπτικές ανάπτυξης - διαφανείς τάσεις στο ελληνικό αστικό σύστημα

<p>HR3∶ 16 hours hypoxia followed by 3 hours reoxygenation.</p

ETB receptor protects the tubulointerstitium in experimental thrombotic microangiopathy

ETB receptor protects the tubulointerstitium in experimental thrombotic microangiopathy.BackgroundThe characteristic features of thrombotic microangiopathy (TMA) include glomerular and peritubular capillary endothelial cell injury with thrombus formation and subsequent ischemic tubulointerstitial damage. The endothelin ETB receptor has been shown to mediate both endothelial cell proliferation and vasodilation, and we therefore hypothesized that blockade of this receptor might promote more severe injury in this model.MethodsTMA was induced in recently established transgenic rats that lack expression of ETB receptor in the kidney; these animals were compared to control rats with TMA both in the short-term (days 1 and 3) when acute glomerular injury was most manifest, and the long-term (day 17) when glomeruli have recovered but tubulointerstitial injury is still present. Renal damage was assessed by histological analysis and blood urea nitrogen (BUN) measurements.ResultsNo difference in the TMA model was observed between rats with and without ETB receptor on days 1 or 3. At day 17, however, rats without the ETB receptor showed more severe tubulointerstitial injury compared with those with ETB receptor, which was associated with higher BUN levels. The tubulointerstitial damage was associated with a more severe loss of peritubular capillaries.ConclusionsThese findings suggest that the ETB receptor may protect peritubular capillaries under the ischemic insult, and serve a defensive role in the tubulointerstitium induced by renal microvascular injury

Mitochondrial Abnormality Facilitates Cyst Formation in Autosomal Dominant Polycystic Kidney Disease

ABSTRACT Autosomal dominant polycystic kidney disease (ADPKD) constitutes the most inherited kidney disease. Mutations in the PKD1 and PKD2 genes, encoding the polycystin 1 and polycystin 2 Ca2+ ion channels, respectively, result in tubular epithelial cell-derived renal cysts. Recent clinical studies demonstrate oxidative stress to be present early in ADPKD. Mitochondria comprise the primary reactive oxygen species source and also their main effector target; however, the pathophysiological role of mitochondria in ADPKD remains uncharacterized. To clarify this function, we examined the mitochondria of cyst-lining cells in ADPKD model mice (Ksp-Cre PKD1flox/flox) and rats (Han:SPRD Cy/+), demonstrating obvious tubular cell morphological abnormalities. Notably, the mitochondrial DNA copy number and peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) expression were decreased in ADPKD model animal kidneys, with PGC-1α expression inversely correlated with oxidative stress levels. Consistent with these findings, human ADPKD cyst-derived cells with heterozygous and homozygous PKD1 mutation exhibited morphological and functional abnormalities, including increased mitochondrial superoxide. Furthermore, PGC-1α expression was suppressed by decreased intracellular Ca2+ levels via calcineurin, p38 mitogen-activated protein kinase (MAPK), and nitric oxide synthase deactivation. Moreover, the mitochondrion-specific antioxidant MitoQuinone (MitoQ) reduced intracellular superoxide and inhibited cyst epithelial cell proliferation through extracellular signal-related kinase/MAPK inactivation. Collectively, these results indicate that mitochondrial abnormalities facilitate cyst formation in ADPKD

A rat model of human FENIB (familial encephalopathy with neuroserpin inclusion bodies)

金沢大学大学院医学系研究科脳細胞分子学FENIB (familial encephalopathy with neuroserpin inclusion bodies) is caused by intracellular accumulation/polymerization of mutant neuroserpins in the endoplasmic reticulum (ER). Transgenic rats overexpressing megsin (Tg meg), a newly identified serine protease inhibitor (serpin), demonstrated intraneuronal periodic-acid Schiff (PAS)-positive inclusions distributed throughout deeper layers of cerebral cortex, CA1 of the hippocampus, and substantia nigra. Hippocampal extracts from Tg meg rats showed increased expression of ER stress proteins, and activation of caspases-12 and -3, associated with decreased neuronal density. Enhanced ER stress was also observed in dopaminergic neurons in the substantia nigra, in parallel with decreased neuronal viability and motor coordination. In each case, PAS-positive inclusions were also positive for megsin. These data suggest that overexpression of megsin results in ER stress, eventuating in the formation of PAS-positive inclusions. Tg meg rats provide a novel model of FENIB, where accumulation of serpins in the ER induces selective dysfunction/loss of specific neuronal populations. © 2006 Elsevier Inc. All rights reserved

Bone marrow stromal cell antigen-1 (CD157) regulated by sphingosine kinase 2 mediates kidney fibrosis

Chronic kidney disease is a progressive disease that may lead to end-stage renal disease. Interstitial fibrosis develops as the disease progresses. Therapies that focus on fibrosis to delay or reverse progressive renal failure are limited. We and others showed that sphingosine kinase 2-deficient mice (Sphk2−/−) develop less fibrosis in mouse models of kidney fibrosis. Sphingosine kinase2 (SphK2), one of two sphingosine kinases that produce sphingosine 1- phosphate (S1P), is primarily located in the nucleus. S1P produced by SphK2 inhibits histone deacetylase (HDAC) and changes histone acetylation status, which can lead to altered target gene expression. We hypothesized that Sphk2 epigenetically regulates downstream genes to induce fibrosis, and we performed a comprehensive analysis using the combination of RNA-seq and ChIP-seq. Bst1/CD157 was identified as a gene that is regulated by SphK2 through a change in histone acetylation level, and Bst1−/− mice were found to develop less renal fibrosis after unilateral ischemia-reperfusion injury, a mouse model of kidney fibrosis. Although Bst1 is a cell-surface molecule that has a wide variety of functions through its varied enzymatic activities and downstream intracellular signaling pathways, no studies on the role of Bst1 in kidney diseases have been reported previously. In the current study, we demonstrated that Bst1 is a gene that is regulated by SphK2 through epigenetic change and is critical in kidney fibrosis

Activation of Sympathetic Signaling in Macrophages Blocks Systemic Inflammation and Protects against Renal Ischemia-Reperfusion Injury

Background: The sympathetic nervous system regulates immune cell dynamics. However, the detailed role of sympathetic signaling in inflammatory diseases is still unclear because it varies according to the disease situation and responsible cell types. This study focused on identifying the functions of sympathetic signaling in macrophages in LPS-induced sepsis and renal ischemia-reperfusion injury (IRI).Methods: We performed RNA sequencing of mouse macrophage cell lines to identify the critical gene that mediates the anti-inflammatory effect of β2-adrenergic receptor (Adrb2) signaling. We also examined the effects of salbutamol (a selective Adrb2 agonist) in LPS-induced systemic inflammation and renal IRI. Macrophage-specific Adrb2 conditional knockout (cKO) mice and the adoptive transfer of salbutamol-treated macrophages were used to assess the involvement of macrophage Adrb2 signaling.Results: In vitro, activation of Adrb2 signaling in macrophages induced the expression of T cell Ig and mucin domain 3 (Tim3), which contributes to anti-inflammatory phenotypic alterations. In vivo, salbutamol administration blocked LPS-induced systemic inflammation and protected against renal IRI; this protection was mitigated in macrophage-specific Adrb2 cKO mice. The adoptive transfer of salbutamol-treated macrophages also protected against renal IRI. Single-cell RNA sequencing revealed that this protection was associated with the accumulation of Tim3-expressing macrophages in the renal tissue.Conclusions: The activation of Adrb2 signaling in macrophages induces anti-inflammatory phenotypic alterations partially via the induction of Tim3 expression, which blocks LPS-induced systemic inflammation and protects against renal IRI