Integrative analysis of microRNA-mediated mitochondrial dysfunction in hippocampal neural progenitor cell death in relation with Alzheimer's disease

Adult hippocampal neurogenesis plays a pivotal role in maintaining cognitive brain function; however, this process diminishes with age, particularly in patients with neurodegenerative disorders. While small, non-coding microRNAs (miRNAs) are crucial for hippocampal neural stem (HCN) cell maintenance, their involvement in neurodegenerative disorders remains unclear. This study aims to elucidate the mechanisms through which miRNAs regulate HCN cell death and their potential involvement in neurodegenerative disorder. We performed a comprehensive microarray-based analysis to investigate changes in miRNA expression in insulin-deprived HCN cells, as an in vitro model for cognitive impairment. Remarkably, miR-150-3p, miR-323-5p, and miR-370-3p which increased significantly over time following insulin withdrawal, induced pronounced mitochondrial fission and dysfunction, ultimately leading to HCN cell death. Notably, these miRNAs collectively target the mitochondrial fusion protein OPA1, with miR-150-3p also targeting MFN2. Furthermore, data-driven analyses involving human subjects within the hippocampus and brain revealed significant reductions of OPA1 and MFN2 in the Alzheimer's disease (AD) patients. Our results indicate that miR-150-3p, miR-323-5p, and miR-370-3p contribute to deficits in hippocampal neurogenesis by modulating mitochondrial dynamics. Our findings provide a novel insight into the intricate connection between miRNAs and mitochondrial dynamics, shedding light on their potential involvement in conditions characterized by deficits in hippocampal neurogenesis, such as AD.

Effects of flow rate accuracy in two-day anticancer drug infusion with disposable pumps on plasma drug concentrations.

BACKGROUND: Elastomeric pumps have a curved infusion rate profile over infusion time. Chemically driven pumps can overcome such limitations of elastomeric pumps and infuse constantly. However, studies on the pharmacokinetic benefit of chemically-driven pumps are insufficient. OBJECTIVE: This study aimed to determine effects of constant infusion with a chemically-driven pump on plasma drug concentrations compared to elastomeric pumps. METHODS: Infusion rate profiles of a chemically driven pump and two elastomeric pumps were measured in vitro tests under three height conditions of drug reservoir. Plasma drug concentrations were estimated using a pharmacokinetic model of 5-fluorouracil (5FU). RESULTS: The chemically-driven pump was more accurate than elastomeric pumps during the total infusion time (Root-mean-square-error (RMSE): 3% vs. 13%) which thus reduced its deviation of plasma 5FU concentration over time to one-fifth of that with an elastomeric pump. The chemically-driven pump had less than 5% of RMSE despite the influence of height difference. CONCLUSION: Although chemically-driven pumps maintained plasma 5FU concentration successfully and elastomeric pumps did not, both pumps were proper for 5FU infusion because the time-dependent changes in infusion rate did not affect the area under the curve. Chemically driven pumps would be more advantageous for drugs that are sensitive to their plasma concentrations.

Mobilization of monocytic myeloid-derived suppressor cells is regulated by PTH1R activation in bone marrow stromal cells.

Myeloid-derived suppressor cells (MDSCs) are bone marrow (BM)-derived immunosuppressive cells in the tumor microenvironment, but the mechanism of MDSC mobilization from the BM remains unclear. We investigated how BM stromal cell activation by PTH1R contributes to MDSC mobilization. PTH1R activation by parathyroid hormone (PTH) or PTH-related peptide (PTHrP), a tumor-derived counterpart, mobilized monocytic (M-) MDSCs from murine BM without increasing immunosuppressive activity. In vitro cell-binding assays demonstrated that α4ß1 integrin and vascular cell adhesion molecule (VCAM)-1, expressed on M-MDSCs and osteoblasts, respectively, are key to M-MDSC binding to osteoblasts. Upon PTH1R activation, osteoblasts express VEGF-A and IL6, leading to Src family kinase phosphorylation in M-MDSCs. Src inhibitors suppressed PTHrP-induced MDSC mobilization, and Src activation in M-MDSCs upregulated two proteases, ADAM-17 and MMP7, leading to VCAM1 shedding and subsequent disruption of M-MDSC tethering to osteoblasts. Collectively, our data provide the molecular mechanism of M-MDSC mobilization in the bones of tumor hosts.

New machine learning-based automatic high-throughput video tracking system for assessing water toxicity using Daphnia Magna locomotory responses.

Daphnia magna is an important organism in ecotoxicity studies because it is sensitive to toxic substances and easy to culture in laboratory conditions. Its locomotory responses as a biomarker are highlighted in many studies. Over the last several years, multiple high-throughput video tracking systems have been developed to measure the locomotory responses of Daphnia magna. These high-throughput systems, used for high-speed analysis of multiple organisms, are essential for efficiently testing ecotoxicity. However, existing systems are lacking in speed and accuracy. Specifically, speed is affected in the biomarker detection stage. This study aimed to develop a faster and better high-throughput video tracking system using machine learning methods. The video tracking system consisted of a constant temperature module, natural pseudo-light, multi-flow cell, and an imaging camera for recording videos. To measure Daphnia magna movements, we developed a tracking algorithm for automatic background subtraction using k-means clustering, Daphnia classification using machine learning methods (random forest and support vector machine), and tracking each Daphnia magna location using the simple online real-time tracking algorithm. The proposed tracking system with random forest performed the best in terms of identification (ID) precision, ID recall, ID F1 measure, and ID switches, with scores of 79.64%, 80.63%, 78.73%, and 16, respectively. Moreover, it was faster than existing tracking systems such as Lolitrack and Ctrax. We conducted an experiment to observe the impact of toxicants on behavioral responses. Toxicity was measured manually in the laboratory and automatically using the high-throughput video tracking system. The median effective concentration of Potassium dichromate measured in the laboratory and using the device was 1.519 and 1.414, respectively. Both measurements conformed to the guideline provided by the Environmental Protection Agency of the United States; therefore, our method can be used for water quality monitoring. Finally, we observed Daphnia magna behavioral responses in different concentrations after 0, 12, 18, and 24 h and found that there was a difference in movement according to the concentration at all hours.

mTOR inhibition as a novel gene therapeutic strategy for diabetic retinopathy.

In addition to laser photocoagulation, therapeutic interventions for diabetic retinopathy (DR) have heretofore consisted of anti-VEGF drugs, which, besides drawbacks inherent to the treatments themselves, are limited in scope and may not fully address the condition's complex pathophysiology. This is because DR is a multifactorial condition, meaning a gene therapy focused on a target with broader effects, such as the mechanistic target of rapamycin (mTOR), may prove to be the solution in overcoming these concerns. Having previously demonstrated the potential of a mTOR-inhibiting shRNA packaged in a recombinant adeno-associated virus to address a variety of angiogenic retinal diseases, here we explore the effects of rAAV2-shmTOR-SD in a streptozotocin-induced diabetic mouse model. Delivered via intravitreal injection, the therapeutic efficacy of the virus vector upon early DR processes was examined. rAAV2-shmTOR-SD effectively transduced mouse retinas and therein downregulated mTOR expression, which was elevated in sham-treated and control shRNA-injected (rAAV2-shCon-SD) control groups. mTOR inhibition additionally led to marked reductions in pericyte loss, acellular capillary formation, vascular permeability, and retinal cell layer thinning, processes that contribute to DR progression. Immunohistochemistry showed that rAAV2-shmTOR-SD decreased ganglion cell loss and pathogenic Müller cell activation and proliferation, while also having anti-apoptotic activity, with these effects suggesting the therapeutic virus vector may be neuroprotective. Taken together, these results build upon our previous work to demonstrate the broad ability of rAAV2-shmTOR-SD to address aspects of DR pathophysiology further evidencing its potential as a human gene therapeutic strategy for DR.

Tumor-Suppressive Effect of Metformin via the Regulation of M2 Macrophages and Myeloid-Derived Suppressor Cells in the Tumor Microenvironment of Colorectal Cancer.

Myeloid-derived suppressor cells (MDSCs) and M2 macrophages in the tumor microenvironment contribute to tumor progression by inducing immune tolerance to tumor antigens and cancer cells. Metformin, one of the most common diabetes drugs, has shown anti-inflammatory and anti-tumor effects. However, the effects of metformin on inflammatory cells of the tumor microenvironment and its underlying mechanisms remain unclarified. In this study, we investigated the effect of metformin on M2 macrophages and MDSCs using monocyte THP-1 cells and a dextran sodium sulfate (DSS)-treated ApcMin/+ mouse model of colon cancer. Metformin decreased the fractions of MDSCs expressing CD33 and arginase, as well as M2 macrophages expressing CD206 and CD163. The inhibitory effect of metformin and rapamycin on MDSCs and M2 macrophages was reversed by the co-treatment of Compound C (an AMP-activated protein kinase (AMPK) inhibitor) or mevalonate. To examine the effect of protein prenylation and cholesterol synthesis (the final steps of the mevalonate pathway) on the MDSC and M2 macrophage populations, we used respective inhibitors (YM53601; SQLE inhibitor, FTI-277; farnesyl transferase inhibitor, GGTI-298; geranylgeranyl transferase inhibitor) and found that the MDSC and M2 populations were suppressed by the protein prenylation inhibitors. In the DSS-treated ApcMin/+ mouse colon cancer model, metformin reduced the number and volume of colorectal tumors with decreased populations of MDSCs and M2 macrophages in the tumor microenvironment. In conclusion, the inhibitory effect of metformin on MDSCs and M2 macrophages in the tumor microenvironment of colon cancers is mediated by AMPK activation and subsequent mTOR inhibition, leading to the downregulation of the mevalonate pathway.

Thermal Gelation for Synthesis of Surface-Modified Silica Aerogel Powders.

A spherical silica aerogel powder with hydrophobic surfaces displaying a water contact angle of 147° was synthesized from a water glass-in-hexane emulsion through ambient pressure drying. Water glass droplets containing acetic acid and ethyl alcohol were stabilized in n-hexane with a surfactant. Gelation was performed by heating the droplets, followed by solvent exchange and surface modification using a hexamethyldisilazane (HMDS)/n-hexane solution. The pH of the silicic acid solution was crucial in obtaining a highly porous silica aerogel powder with a spherical morphology. The thermal conductivity, tapped density, pore volume, and BET surface area of the silica aerogel powder were 22.4 mW·m-1K-1, 0.07 g·cm-3, 4.64 cm3·g-1, and 989 m2·g-1, respectively. Fourier transform infrared (FT-IR) spectroscopy analysis showed that the silica granule surface was modified by Si-CH3 groups, producing a hydrophobic aerogel.

TCTP protein degradation by targeting mTORC1 and signaling through S6K, Akt, and Plk1 sensitizes lung cancer cells to DNA-damaging drugs.

Translationally controlled tumor protein (TCTP) is expressed in many tissues, particularly in human tumors. It plays a role in malignant transformation, apoptosis prevention, and DNA damage repair. The signaling mechanisms underlying TCTP regulation in cancer are only partially understood. Here, we investigated the role of mTORC1 in regulating TCTP protein levels, thereby modulating chemosensitivity, in human lung cancer cells and an A549 lung cancer xenograft model. The inhibition of mTORC1, but not mTORC2, induced ubiquitin/proteasome-dependent TCTP degradation without a decrease in the mRNA level. PLK1 activity was required for TCTP ubiquitination and degradation and for its phosphorylation at Ser46 upon mTORC1 inhibition. Akt phosphorylation and activation was indispensable for rapamycin-induced TCTP degradation and PLK1 activation, and depended on S6K inhibition, but not mTORC2 activation. Furthermore, the minimal dose of rapamycin required to induce TCTP proteolysis enhanced the efficacy of DNA-damaging drugs, such as cisplatin and doxorubicin, through the induction of apoptotic cell death in vitro and in vivo. This synergistic cytotoxicity of these drugs was induced irrespective of the functional status of p53. These results demonstrate a new mechanism of TCTP regulation in which the mTORC1/S6K pathway inhibits a novel Akt/PLK1 signaling axis and thereby induces TCTP protein stabilization and confers resistance to DNA-damaging agents. The results of this study suggest a new therapeutic strategy for enhancing chemosensitivity in lung cancers regardless of the functional status of p53.

A Basic Domain-Derived Tripeptide Inhibits MITF Activity by Reducing its Binding to the Promoter of Target Genes.

The keratinocytes in UV-irradiated skin produce and secrete α-melanocyte-stimulating hormone. α-Melanocyte-stimulating hormone upregulates the expression of MITF in melanocytes through the cAMP‒protein kinase A‒CREB signaling pathway. Thereafter, MITF induces the expression of melanogenic genes, including the tyrosinase gene TYR and TYRP-1 and TYRP-2 genes, which leads to the synthesis and accumulation of melanin. In this study, we examined whether MITF basic region-derived tripeptides can bind to the DNA-binding domain of MITF and inhibit MITF-induced melanogenesis through the inhibition of MITF‒DNA binding. MITF-KGR, a representative MITF-derived tripeptide, suppressed the transcriptional activity of MITF by disrupting its binding to the promoter region of the target genes, which resulted in the inhibition of skin epidermis thickness and melanin synthesis in vivo and in vitro. Our results indicate that MITF-KGR exerts an inhibitory effect on melanogenesis by targeting MITF.

Fabrication of Durable Ni-YSZ Hydrogen Electrode for High-Temperature Solid Electrolyzer Cells.

Solid oxide electrolyzer cells with an Ni-Fe-yttria-stabilized zirconia (Ni-Fe-YSZ) hydrogen electrode as the cathode, lanthanum strontium ferrite (LSCF)-gadolinia-doped ceria (GDC) air electrode as the anode, and YSZ as the electrolyte were fabricated, and the oxidation protection effect of sacrificial Fe particles was investigated. X-ray diffraction analysis indicated that Ni was protected from oxidation under a water vapor atmosphere by sacrificial Fe. Scanning electron microscopy observations suggested that the Ni particles accumulated in the Ni-YSZ hydrogen electrode, which might have been associated with the partial oxidation of Ni during cell operation at 700 °C in 50% H2O/15% H2/35% Ar atmosphere. No appreciable microstructural changes were observed for the Ni-Fe-YSZ hydrogen electrode. Furthermore, the presence of the sacrificial Fe particles could be responsible for the superior durability of the cell, compared with that of the cell featuring the conventional Ni-YSZ hydrogen electrode.

A structurally optimized FXR agonist, MET409, reduced liver fat content over 12 weeks in patients with non-alcoholic steatohepatitis.

BACKGROUND & AIMS: The benefits of farnesoid X receptor (FXR) agonists in patients with non-alcoholic steatohepatitis (NASH) have been validated, although improvements in efficacy and/or tolerability remain elusive. Herein, we aimed to assess the performance of a structurally optimized FXR agonist in patients with NASH. METHODS: In this 12-week, randomized, placebo-controlled study, we evaluated MET409 - a non-bile acid agonist with a unique chemical scaffold - in patients with NASH. Patients were randomized to receive either 80 mg (n = 20) or 50 mg (n = 19) of MET409, or placebo (n = 19). RESULTS: At Week 12, MET409 lowered liver fat content (LFC), with mean relative reductions of 55% (80 mg) and 38% (50 mg) vs. 6% in placebo (p <0.001). MET409 achieved ≥30% relative LFC reduction in 93% (80 mg) and 75% (50 mg) of patients vs. 11% in placebo (p <0.001) and normalized LFC (≤5%) in 29% (80 mg) and 31% (50 mg) of patients vs. 0% in placebo (p <0.05). An increase in alanine aminotransferase (ALT) was observed with MET409, confounding Week 12 changes from baseline (-25% for 80 mg, 28% for 50 mg). Nonetheless, MET409 achieved ≥30% relative ALT reduction in 50% (80 mg) and 31% (50 mg) of patients vs. 17% in placebo. MET409 was associated with on-target high-density lipoprotein cholesterol decreases (mean changes of -23.4% for 80 mg and -20.3% for 50 mg vs. 2.6% in placebo) and low-density lipoprotein cholesterol (LDL-C) increases (mean changes of 23.7% for 80 mg and 6.8% for 50 mg vs. -1.5% in placebo). Pruritus (mild-moderate) occurred in 16% (50 mg) and 40% (80 mg) of MET409-treated patients. CONCLUSION: MET409 lowered LFC over 12 weeks in patients with NASH and delivered a differentiated pruritus and LDL-C profile at 50 mg, providing the first clinical evidence that the risk-benefit profile of FXR agonists can be enhanced through structural optimization. LAY SUMMARY: Activation of the farnesoid X receptor (FXR) is a clinically validated approach for treating non-alcoholic steatohepatitis (NASH), although side effects such as itching or increases in low-density lipoprotein cholesterol are frequently dose-limiting. MET409, an FXR agonist with a unique chemical structure, led to significant liver fat reduction and delivered a favorable side effect profile after 12 weeks of treatment in patients with NASH. These results provide the first clinical evidence that the risk-benefit profile of FXR agonists can be enhanced.

CD99-PTPN12 Axis Suppresses Actin Cytoskeleton-Mediated Dimerization of Epidermal Growth Factor Receptor.

The epidermal growth factor receptor (EGFR), a member of ErbB receptor tyrosine kinase (RTK) family, is activated through growth factor-induced reorganization of the actin cytoskeleton and subsequent dimerization. We herein explored the molecular mechanism underlying the suppression of ligand-induced EGFR dimerization by CD99 agonists and its relevance to tumor growth in vivo. Epidermal growth factor (EGF) activated the formation of c-Src/focal adhesion kinase (FAK)-mediated intracellular complex and subsequently induced RhoA-and Rac1-mediated actin remodeling, resulting in EGFR dimerization and endocytosis. In contrast, CD99 agonist facilitated FAK dephosphorylation through the HRAS/ERK/PTPN12 signaling pathway, leading to inhibition of actin cytoskeletal reorganization via inactivation of the RhoA and Rac1 signaling pathways. Moreover, CD99 agonist significantly suppressed tumor growth in a BALB/c mouse model injected with MDA-MB-231 human breast cancer cells. Taken together, these results indicate that CD99-derived agonist ligand inhibits epidermal growth factor (EGF)-induced EGFR dimerization through impairment of cytoskeletal reorganization by PTPN12-dependent c-Src/FAK inactivation, thereby suppressing breast cancer growth.

Real-time monitoring of oncolytic VSV properties in a novel in vitro microphysiological system containing 3D multicellular tumor spheroids.

As a new class of cancer therapeutic agents, oncolytic viruses (OVs) have gained much attention not only due to their ability to selectively replicate in and lyse tumor cells, but also for their potential to stimulate antitumor immune responses. As a result, there is an increasing need for in vitro modeling systems capable of recapitulating the 3D physiological tumor microenvironment. Here, we investigated the potential of our recently developed microphysiological system (MPS), featuring a vessel-like channel to reflect the in vivo tumor microenvironment and serving as culture spaces for 3D multicellular tumor spheroids (MCTSs). The MCTSs consist of cancer A549 cells, stromal MRC5 cells, endothelial HUVECs, as well as the extracellular matrix. 3D MCTSs residing in the MPS were infected with oncolytic VSV expressing GFP (oVSV-GFP). Post-infection, GFP signal intensity increased only in A549 cells of the MPS. On the other hand, HUVECs were susceptible to virus infection under 2D culture and IFN-ß secretion was quite delayed in HUVECs. These results thus demonstrate that OV antitumoral characteristics can be readily monitored in the MPS and that its behavior therein somewhat differs compared to its activity in 2D system. In conclusion, we present the first application of the MPS, an in vitro model that was developed to better reflect in vivo conditions. Its various advantages suggest the 3D MCTS-integrated MPS can serve as a first line monitoring system to validate oncolytic virus efficacy.

A novel nanoparticle-based theranostic agent targeting LRP-1 enhances the efficacy of neoadjuvant radiotherapy in colorectal cancer.

Neoadjuvant radiotherapy has become an important therapeutic option for colorectal cancer (CRC) patients, whereas complete tumor response is observed only in 20-30% patients. Therefore, the development of diagnostic probe for radio-resistance is important to decide an optimal treatment timing and strategy for radiotherapy-resistant CRC patients. In this study, using the patient-derived xenograft (PDX) mouse model established with a radio-resistant CRC tumor tissue, we found low-density lipoprotein receptor-related protein-1 (LRP-1) as a radio-resistant marker protein induced by initial-dose radiation in radio-resistant CRC tumors. Simultaneously, we discovered a LRP-1 targeting peptide in a radio-resistant CRC PDX through in vivo peptide screening. We next engineered the theranostic agent made of human serum albumin nanoparticles (HSA NPs) containing 5-FU for chemo-radiotherapy and decorating LRP-1-targeting peptide for tumor localization, Cy7 fluorophore for diagnostic imaging. The nanoparticle-based theranostic agent accurately targeted the tumor designated by LRP-1 responding radiation and showed dramatically improved therapeutic efficacy in the radio-resistant PDX model. In conclusion, we have identified LRP-1 as a signature protein of radio-resistant CRC and successfully developed LRP-1-targeting HSA-NP containing 5-FU that is a novel theranostic tool for both diagnostic imaging and neoadjuvant therapy of CRC patients. This approach is clinically applicable to improve the effectiveness of neo-adjuvant radiotherapy and increase the ratio of complete tumor response in radio-resistant CRC.

Circulating Osteocalcin-Positive Cells as a Novel Diagnostic Biomarker for Bone Metastasis in Breast Cancer Patients.

Current diagnosis of bone metastasis (BM) in breast cancer relies on structural changes of bone that occur only in the advanced stage. A sensitive biomarker for detecting early progression of bone metastasis is urgently required. We performed clinical and preclinical studies to investigate diagnostic value of circulating osteocalcin-positive cells (cOC) in breast cancer bone metastasis. Metastatic breast cancer patients (n = 92) with or without bone metastasis (ie, BM+ or BM- ) were enrolled, and cOC were measured at enrollment. Patients were followed up for bone metastasis progression for 18 months. BM+ patients (n = 59) were divided into progressive (PD) or stable disease (SD) groups, based on imaging studies at the end of the 18-month study. The PD group had higher baseline cOC compared with the SD group. Furthermore, higher cOC resulted in reduced BM progression-free survival. Three patients in the BM- group (n = 33) developed new BM during the 18-month study, and these patients had a higher level of baseline cOC compared with the remaining BM- patients. In murine preclinical studies, cOC increased at early time points when micro-metastases were evident only by histology but undetectable by bioluminescence imaging. Also, cOC levels predicted the progression of BM and correlated significantly with BM tumor burden. cOC increased in the early phase of breast cancer BM and can predict BM progression, supporting cOC as a potential novel biomarker. © 2020 American Society for Bone and Mineral Research.

Evaluation of Bystander Infection of Oncolytic Virus using a Medium Flow Integrated 3D In Vitro Microphysiological System.

Replicable oncolytic viruses (OVs) induce tumor cell lysis and release viral progeny. The released progeny virions and cell debris can spread within surrounding tumor cells or blood vessels. These released molecules may also induce bystander damage in additional tumor cells through spreading within surrounding tumor cells or blood vessels. However, this effect has not been clearly demonstrated due to the difficulty of direct observation. Here, the bystander infection of OVs by vessel delivery and selective infection in 3D multicellular tumoroids (MCTs) in an in vitro microphysiological system (MPS) with integrated medium flow is demonstrated. This study uses replicable vesicular stomatitis virus (VSV)-green fluorescence protein (GFP) to identify the location of infection in 3D MCTs. Using this MPS, the oncoselective infection by VSV-GFP and the spreading by delivery of OVs through flow via block-to-block linkage of the primary infected MPS with uninfected 3D MCTs in an integrated MPS is observed. This MPS enables real-time monitoring and various analysis for the bystander infection of OVs. It is expected that the 3D in vitro MPS can be suitable to investigate the oncoselective spreading and bystander infection of OVs.

Negative Regulation of IKKε-Mediated IRF7 Phosphorylation by HSP70.

Immune reactions are controlled by the delicate spatiotemporal orchestration of multiple cells communicating by cytokines. Studies of cytokines that began with the discovery of IFN focused on positive regulatory mechanisms that induce secretion in response to harmful stimuli. However, there is a growing awareness that negative regulatory mechanisms that stop secretion of cytokines at specific times and spaces are also important for a successful immune reaction. Type I IFN is the primary cytokine in innate immunity. Although its induction is a prerequisite for the consequent adaptive immune reaction, its oversecretion can cause destructive tissue damage. IFN regulatory factor 7 (IRF7) is a master transcription factor of type I IFN, and multiple observations indicate the key role of IRF7 and the importance of its negative regulation. In this study, we found that the inducible heat shock protein 70 (HSP70) regulated the early type I IFN response by using mice knockout for HSP70. HSP70 dampened IRF7 activation; the inhibitory effect of HSP70 over IKKε-mediated IRF7 activation originated from simple competitive binding. This suggests the possibility of blocking the feed-forward loop between IRF7 and type I IFN in stress environments with increased expression of HSP70.

Computer simulations of steady concentration peritoneal dialysis.

BACKGROUND: Steady concentration peritoneal dialysis (SCPD), which maintains transperitoneal osmotic gradient by infusing 50% glucose solution throughout the dwell time, has been proposed as a potent treatment for peritoneal dialysis (PD) patients with fluid overload. However, SCPD has yet to be explored theoretically. Here, we investigated SCPD via computer simulations. METHODS: A model was developed by adding the variables for infusing 50% glucose solution to a traditional three-pore model for continuous ambulatory PD. The simulated scenarios involved the instillation of 2-L dialysate, 1.36% or 2.27%, followed by the infusion of 50% glucose solution, varying the rate from 0 mL/h to 90 mL/h. A dwell with 3.86% dialysate was also simulated for the purpose of comparison. Four sets of patient parameters corresponding to peritoneal transport categories were used. RESULTS: The net ultrafiltration (UF) during SCPD increased with time as well as with glucose infusion rate. The glucose absorption and sodium removal of SCPD were slightly higher than those of the conventional dwell with 3.86% dialysate under the condition of the same net UF and dwell time. SCPD resulted in the larger UF and the lower peak intraperitoneal glucose concentration when it was simulated with the higher transport properties. CONCLUSIONS: These simulations indicate that SCPD can improve UF beyond those achievable by a conventional 3.86% glucose exchange while also exhibiting a lower peak osmolarity in the dialysate as compared to a conventional 3.86% dwell. However, further studies are needed to confirm these theoretical findings.

Inhibition of mTOR via an AAV-Delivered shRNA Tested in a Rat OIR Model as a Potential Antiangiogenic Gene Therapy.

Purpose: Recent studies have shown that inhibitors of the mechanistic target of rapamycin (mTOR) play important roles in proliferating endothelial cells within the retinal vasculature. Here we explore the effects of inhibiting mTOR as a potential gene therapeutic against pathological retinal angiogenesis in a rat model of oxygen-induced retinopathy (OIR). Methods: Sprague-Dawley pups were used to generate the OIR model, with a recombinant adeno-associated virus expressing an shRNA (rAAV2-shmTOR-GFP) being administered via intravitreal injection on returning the rats to normoxia, with appropriate controls. Immunohistochemistry and TUNEL assays, as well as fluorescein angiography, were performed on transverse retinal sections and flat mounts, respectively, to determine the in vivo effects of mTOR inhibition. Results: Compared with normal control rats, as well as OIR model animals that were either untreated (20.95 ± 6.85), mock-treated (14.50 ± 2.47), or injected with a control short hairpin RNA (shRNA)-containing virus vector (16.64 ± 4.92), rAAV2-shmTOR-GFP (4.28 ± 2.86, P = 0.00103) treatment resulted in dramatically reduced neovascularization as a percentage of total retinal area. These results mirrored quantifications of retinal avascular area and vessel tortuosity, with rAAV2-shmTOR-GFP exhibiting significantly greater therapeutic efficacy than the other treatments. The virus vector was additionally shown to reduce inflammatory cell infiltration into retinal tissue and possess antiapoptotic properties, both these processes having been implicated in the pathophysiology of angiogenic retinal disorders. Conclusions: Taken together, these results demonstrate the strong promise of rAAV2-shmTOR-GFP as an effective and convenient gene therapy for the treatment of neovascular retinal diseases.

Fabrication of Ce-Promoted Ni/Al2O3 Methane Steam Reforming Catalysts by Impregnation.

CeO2-promoted Ni/Al2O3 catalysts were fabricated by impregnation. The effects of the CeO2 promotion and impregnation order on the microstructural evolution and catalytic durability were investigated for methane steam reforming. The CeO2-promoter nanoparticles resulted in good dispersion and reduced particle size of Ni catalysts. The enhanced durability of CeO2-promoted Ni/Al2O3 catalysts might be associated with the depression of carbon deposition by the presence of CeO2-promoter nanoparticles.