[HCO(3)(-)]-regulated expression and activity of soluble adenylyl cyclase in corneal endothelial and Calu-3 cells

BACKGROUND: Bicarbonate activated Soluble Adenylyl Cyclase (sAC) is a unique cytoplasmic and nuclear signaling mechanism for the generation of cAMP. HCO(3)(- )activates sAC in bovine corneal endothelial cells (BCECs), increasing [cAMP] and stimulating PKA, leading to phosphorylation of the cystic fibrosis transmembrane-conductance regulator (CFTR) and increased apical Cl(- )permeability. Here, we examined whether HCO(3)(- )may also regulate the expression of sAC and thereby affect the production of cAMP upon activation by HCO(3)(- )and the stimulation of CFTR in BCECs. RESULTS: RT-competitive PCR indicated that sAC mRNA expression in BCECs is dependent on [HCO(3)(-)] and incubation time in HCO(3)(-). Immunoblots showed that 10 and 40 mM HCO(3)(- )increased sAC protein expression by 45% and 87%, respectively, relative to cells cultured in the absence of HCO(3)(-). Furthermore, 40 mM HCO(3)(- )up-regulated sAC protein expression in Calu-3 cells by 93%. On the other hand, sAC expression in BCECs and Calu-3 cells was unaffected by changes in bath pH or osmolarity. Interestingly, BCECs pre-treated with10 μM adenosine or 10 μM forskolin, which increase cAMP levels, showed decreased sAC mRNA expression by 20% and 30%, respectively. Intracellular cAMP production by sAC paralleled the time and [HCO(3)(-)]-dependent expression of sAC. Bicarbonate-induced apical Cl(- )permeability increased by 78% (P < 0.01) in BCECs cultured in HCO(3)(-). However for cells cultured in the absence of HCO(3)(-), apical Cl(- )permeability increased by only 10.3% (P > 0.05). CONCLUSION: HCO(3)(- )not only directly activates sAC, but also up-regulates the expression of sAC. These results suggest that active cellular uptake of HCO(3)(- )can contribute to the basal level of cellular cAMP in tissues that express sAC

Astrocytic expression of Parkinson's disease-related A53T α-synuclein causes neurodegeneration in mice

<p>Abstract</p> <p>Background</p> <p>Parkinson's disease (PD) is the most common movement disorder. While neuronal deposition of α-synuclein serves as a pathological hallmark of PD and Dementia with Lewy Bodies, α-synuclein-positive protein aggregates are also present in astrocytes. The pathological consequence of astrocytic accumulation of α-synuclein, however, is unclear.</p> <p>Results</p> <p>Here we show that PD-related A53T mutant α-synuclein, when selectively expressed in astrocytes, induced rapidly progressed paralysis in mice. Increasing accumulation of α-synuclein aggregates was found in presymptomatic and symptomatic mouse brains and correlated with the expansion of reactive astrogliosis. The normal function of astrocytes was compromised as evidenced by cerebral microhemorrhage and down-regulation of astrocytic glutamate transporters, which also led to increased inflammatory responses and microglial activation. Interestingly, the activation of microglia was mainly detected in the midbrain, brainstem and spinal cord, where a significant loss of dopaminergic and motor neurons was observed. Consistent with the activation of microglia, the expression level of cyclooxygenase 1 (COX-1) was significantly up-regulated in the brain of symptomatic mice and in cultured microglia treated with conditioned medium derived from astrocytes over-expressing A53T α-synuclein. Consequently, the suppression of COX-1 activities extended the survival of mutant mice, suggesting that excess inflammatory responses elicited by reactive astrocytes may contribute to the degeneration of neurons.</p> <p>Conclusions</p> <p>Our findings demonstrate a critical involvement of astrocytic α-synuclein in initiating the non-cell autonomous killing of neurons, suggesting the viability of reactive astrocytes and microglia as potential therapeutic targets for PD and other neurodegenerative diseases.</p

Deep constrained siamese hash coding network and load-balanced locality-sensitive hashing for near duplicate image detection

We construct a new efficient near duplicate image detection method using a hierarchical hash code learning neural network and load-balanced Locality Sensitive Hashing (LSH) indexing. We propose a deep constrained siamese hash coding neural network combined with deep feature learning. Our neural network is able to extract effective features for near duplicate image detection. The extracted features are used to construct a LSH-based index. We propose a load-balanced LSH method to produce load-balanced buckets in the hashing process. The load-balanced LSH significantly reduces the query time. Based on the proposed load-balanced LSH, we design an effective and feasible algorithm for near duplicate image detection. Extensive experiments on three benchmark datasets demonstrate the effectiveness of our deep siamese hash encoding network and load-balanced LSH

Dahuang Fuzi Decoction Attenuates Renal Fibrosis and Ameliorates Mitochondrial Dysfunction in Chronic Aristolochic Acid Nephropathy

Objectives. The effects of the traditional formula Dahuang Fuzi Decoction (DFD) on chronic aristolochic acid nephropathy (AAN) in mice and its underlying mechanisms were studied. Methods. Mice were randomly divided into the following six groups: the control group, the model group (AAN), the saline-treated group (AAN + vehicle), the normal dose DFD-treated group (AAN + NDFD), the high dose DFD-treated group (AAN + HDFD), and the rosiglitazone treated group (AAN + Rosi). After treating for 8 weeks, 24 h urine and blood samples were collected and the mice sacrificed to study the biochemical parameters associated with renal function. The samples were analyzed for renal fibrosis and mitochondrial dysfunction (MtD) markers. To achieve that, collagen III, collagen I, mitochondrial DNA copy numbers (mtDNA), mitochondrial membrane potential (MMP), ATP content, and ROS production were evaluated. Results. Our results showed that proteinuria, kidney function, and the renal pathological characteristics were improved by DFD and rosiglitazone. The expression of collagen III and collagen I decreased after treating with either DFD or rosiglitazone. Mitochondrial dysfunction based on the increase in ROS production, decrease in mitochondrial DNA copy numbers, and reduction of MMP and ATP content was improved by DFD and rosiglitazone. Conclusions. DFD could protect against renal impairments and ameliorate mitochondrial dysfunction in chronic AAN mice