Hepatitis C Virus (HCV) Infection and Hepatic Steatosis

There are two discrete forms of steatosis that may be found in patients infected with hepatitis C virus (HCV). Metabolic steatosis can coexist with HCV, regardless of genotype, in patients with risk factors such as obesity, hyperlipidemia, and insulin resistance. The second form of hepatic steatosis in HCV patients is a result of the direct cytopathic effect of genotype 3 viral infections. There have been proposed mechanisms for this process but it remains elusive. Both categories of steatosis tend to hasten the progression of liver fibrosis and therefore prompt recognition and management should be initiated in patients with HCV and steatosis. The authors review the current understanding of the relationship between hepatitis C infection and hepatic steatosis and discuss future research directions

Pharmacogenomics of drug efficacy in the interferon treatment of chronic hepatitis C using classification algorithms

Chronic hepatitis C (CHC) patients often stop pursuing interferon-alfa and ribavirin (IFN-alfa/RBV) treatment because of the high cost and associated adverse effects. It is highly desirable, both clinically and economically, to establish tools to distinguish responders from nonresponders and to predict possible outcomes of the IFN-alfa/RBV treatments. Single nucleotide polymorphisms (SNPs) can be used to understand the relationship between genetic inheritance and IFN-alfa/RBV therapeutic response. The aim in this study was to establish a predictive model based on a pharmacogenomic approach. Our study population comprised Taiwanese patients with CHC who were recruited from multiple sites in Taiwan. The genotyping data was generated in the high-throughput genomics lab of Vita Genomics, Inc. With the wrapper-based feature selection approach, we employed multilayer feedforward neural network (MFNN) and logistic regression as a basis for comparisons. Our data revealed that the MFNN models were superior to the logistic regression model. The MFNN approach provides an efficient way to develop a tool for distinguishing responders from nonresponders prior to treatments. Our preliminary results demonstrated that the MFNN algorithm is effective for deriving models for pharmacogenomics studies and for providing the link from clinical factors such as SNPs to the responsiveness of IFN-alfa/RBV in clinical association studies in pharmacogenomics

Magnitude of Stratification in Human Populations and Impacts on Genome Wide Association Studies

Genome-wide association studies (GWAS) may be biased by population stratification (PS). We conducted empirical quantification of the magnitude of PS among human populations and its impact on GWAS. Liver tissues were collected from 979, 59 and 49 Caucasian Americans (CA), African Americans (AA) and Hispanic Americans (HA), respectively, and genotyped using Illumina650Y (Ilmn650Y) arrays. RNA was also isolated and hybridized to Agilent whole-genome gene expression arrays. We propose a new method (i.e., hgdp-eigen) for detecting PS by projecting genotype vectors for each sample to the eigenvector space defined by the Human Genetic Diversity Panel (HGDP). Further, we conducted GWAS to map expression quantitative trait loci (eQTL) for the ∼40,000 liver gene expression traits monitored by the Agilent arrays. HGDP-eigen performed similarly to the conventional self-eigen methods in capturing PS. However, leveraging the HGDP offered a significant advantage in revealing the origins, directions and magnitude of PS. Adjusting for eigenvectors had minor impacts on eQTL detection rates in CA. In contrast, for AA and HA, adjustment dramatically reduced association findings. At an FDR = 10%, we identified 65 eQTLs in AA with the unadjusted analysis, but only 18 eQTLs after the eigenvector adjustment. Strikingly, 55 out of the 65 unadjusted AA eQTLs were validated in CA, indicating that the adjustment procedure significantly reduced GWAS power. A number of the 55 AA eQTLs validated in CA overlapped with published disease associated SNPs. For example, rs646776 and rs10903129 have previously been associated with lipid levels and coronary heart disease risk, however, the rs10903129 eQTL was missed in the eigenvector adjusted analysis

Anisotropic magnetocaloric response in AlFe2B2

Experimental investigations of the magnetocaloric response of the intermetallic layered AlFe2B2 compound along the principle axes of the orthorhombic cell were carried out using aligned plate-like crystallites with an anisotropic [101] growth habit. Results were confirmed to be consistent with density functional theory calculations. Field-dependent magnetization data confirm that the a-axis is the easy direction of magnetization within the (ac) plane. The magnetocrystalline anisotropy energy required to rotate the spin quantization vector from the c-to the a-axis direction is determined as K∼0.9 MJ/m3 at 50 K. Magnetic entropy change curves measured near the Curie transition temperature of 285 K reveal a large rotating magnetic entropy change of 1.3 J kg−1K−1 at μ0Happ = 2 T, consistent with large differences in magnetic entropy change ΔSmag measured along the a- and c-axes. Overall, this study provides insight of both fundamental and applied relevance concerning pathways for maximizing the magnetocaloric potential of AlFe2B2 for thermal management applications

Endothelium- targeted overexpression of Krüppel- like factor 11 protects the blood- brain barrier function after ischemic brain injury

Microvascular endothelial cell (EC) injury and the subsequent blood- brain barrier (BBB) breakdown are frequently seen in many neurological disorders, including stroke. We have previously documented that peroxisome proliferator- activated receptor gamma (PPARγ)- mediated cerebral protection during ischemic insults needs Krüppel- like factor 11 (KLF11) as a critical coactivator. However, the role of endothelial KLF11 in cerebrovascular function and stroke outcome is unclear. This study is aimed at investigating the regulatory role of endothelial KLF11 in BBB preservation and neurovascular protection after ischemic stroke. EC- targeted overexpression of KLF11 significantly mitigated BBB leakage in ischemic brains, evidenced by significantly reduced extravasation of BBB tracers and infiltration of peripheral immune cells, and less brain water content. Endothelial cell- selective KLF11 transgenic (EC- KLF11 Tg) mice also exhibited smaller brain infarct and improved neurological function in response to ischemic insults. Furthermore, EC- targeted transgenic overexpression of KLF11 preserved cerebral tight junction (TJ) levels and attenuated the expression of pro- inflammatory factors in mice after ischemic stroke. Mechanistically, we demonstrated that KLF11 directly binds to the promoter of major endothelial TJ proteins including occludin and ZO- 1 to promote their activities. Our data indicate that KLF11 functions at the EC level to preserve BBB structural and functional integrity, and therefore, confers brain protection in ischemic stroke. KLF11 may be a novel therapeutic target for the treatment of ischemic stroke and other neurological conditions involving BBB breakdown and neuroinflammation.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/155919/1/bpa12831_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/155919/2/bpa12831.pd

Targeting tumour re-wiring by triple blockade of mTORC1, epidermal growth factor, and oestrogen receptor signalling pathways in endocrine-resistant breast cancer

Background Endocrine therapies are the mainstay of treatment for oestrogen receptor (ER)-positive (ER+) breast cancer (BC). However, resistance remains problematic largely due to enhanced cross-talk between ER and growth factor pathways, circumventing the need for steroid hormones. Previously, we reported the anti-proliferative effect of everolimus (RAD001-mTORC1 inhibitor) with endocrine therapy in resistance models; however, potential routes of escape from treatment via ERBB2/3 signalling were observed. We hypothesised that combined targeting of three cellular nodes (ER, ERBB, and mTORC1) may provide enhanced long-term clinical utility. Methods A panel of ER+ BC cell lines adapted to long-term oestrogen deprivation (LTED) and expressing ESR1wt or ESR1Y537S, modelling acquired resistance to an aromatase-inhibitor (AI), were treated in vitro with a combination of RAD001 and neratinib (pan-ERBB inhibitor) in the presence or absence of oestradiol (E2), tamoxifen (4-OHT), or fulvestrant (ICI182780). End points included proliferation, cell signalling, cell cycle, and effect on ER-mediated transactivation. An in-vivo model of AI resistance was treated with monotherapies and combinations to assess the efficacy in delaying tumour progression. RNA-seq analysis was performed to identify changes in global gene expression as a result of the indicated therapies. Results Here, we show RAD001 and neratinib (pan-ERBB inhibitor) caused a concentration-dependent decrease in proliferation, irrespective of the ESR1 mutation status. The combination of either agent with endocrine therapy further reduced proliferation but the maximum effect was observed with a triple combination of RAD001, neratinib, and endocrine therapy. In the absence of oestrogen, RAD001 caused a reduction in ER-mediated transcription in the majority of the cell lines, which associated with a decrease in recruitment of ER to an oestrogen-response element on the TFF1 promoter. Contrastingly, neratinib increased both ER-mediated transactivation and ER recruitment, an effect reduced by the addition of RAD001. In-vivo analysis of an LTED model showed the triple combination of RAD001, neratinib, and fulvestrant was most effective at reducing tumour volume. Gene set enrichment analysis revealed that the addition of neratinib negated the epidermal growth factor (EGF)/EGF receptor feedback loops associated with RAD001. Conclusions Our data support the combination of therapies targeting ERBB2/3 and mTORC1 signalling, together with fulvestrant, in patients who relapse on endocrine therapy and retain a functional ER

Dual Anti-Inflammatory and Anti-Angiogenic Action of miR-15a in Diabetic Retinopathy

AbstractActivation of pro-inflammatory and pro-angiogenic pathways in the retina and the bone marrow contributes to pathogenesis of diabetic retinopathy. We identified miR-15a as key regulator of both pro-inflammatory and pro-angiogenic pathways through direct binding and inhibition of the central enzyme in the sphingolipid metabolism, ASM, and the pro-angiogenic growth factor, VEGF-A. miR-15a was downregulated in diabetic retina and bone marrow cells. Over-expression of miR-15a downregulated, and inhibition of miR-15a upregulated ASM and VEGF-A expression in retinal cells. In addition to retinal effects, migration and retinal vascular repair function was impaired in miR-15a inhibitor-treated circulating angiogenic cells (CAC). Diabetic mice overexpressing miR-15a under Tie-2 promoter had normalized retinal permeability compared to wild type littermates. Importantly, miR-15a overexpression led to modulation toward nondiabetic levels, rather than complete inhibition of ASM and VEGF-A providing therapeutic effect without detrimental consequences of ASM and VEGF-A deficiencies

Negative correlation of single-cell PAX3:FOXO1 expression with tumorigenicity in rhabdomyosarcoma

Rhabdomyosarcomas (RMS) are phenotypically and functionally heterogeneous. Both primary human RMS cultures and low-passage Myf6Cre,Pax3:Foxo1,p53 mouse RMS cell lines, which express the fusion oncoprotein Pax3:Foxo1 and lack the tumor suppressor Tp53 (Myf6Cre,Pax3:Foxo1,p53), exhibit marked heterogeneity in PAX3:FOXO1 (P3F) expression at the single cell level. In mouse RMS cells, P3F expression is directed by the Pax3 promoter and coupled to eYFP. YFPlow/P3Flow mouse RMS cells included 87% G0/G1 cells and reorganized their actin cytoskeleton to produce a cellular phenotype characterized by more efficient adhesion and migration. This translated into higher tumor-propagating cell frequencies of YFPlow/P3Flow compared with YFPhigh/P3Fhigh cells. Both YFPlow/P3Flow and YFPhigh/P3Fhigh cells gave rise to mixed clones in vitro, consistent with fluctuations in P3F expression over time. Exposure to the anti-tropomyosin compound TR100 disrupted the cytoskeleton and reversed enhanced migration and adhesion of YFPlow/P3Flow RMS cells. Heterogeneous expression of PAX3:FOXO1 at the single cell level may provide a critical advantage during tumor progression