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Item Ferroxitosis: a cell death from modulation of oxidative phosphorylation and PKM2-dependent glycolysis in melanoma(Impact Journals, LLC, 2014-12-30) Lakhter, Alexander J.; Hamilton, James; Dagher, Pierre C.; Mukkamala, Suresh; Hato, Takashi; Dong, X. Charlie; Mayo, Lindsey D.; Harris, Robert A.; Shekhar, Anantha; Ivan, Mircea; Brustovetsky, Nickolay; Naidu, Samisubbu R.; Department of Dermatology, IU School of MedicineReliance on glycolysis is a characteristic of malignancy, yet the development of resistance to BRAF inhibitors in melanoma is associated with gain of mitochondrial function. Concurrent attenuation of oxidative phosphorylation and HIF-1α/PKM2-dependent glycolysis promotes a non-apoptotic, iron- and oxygen-dependent cell death that we term ferroxitosis. The redox cycling agent menadione causes a robust increase in oxygen consumption, accompanied by significant loss of intracellular ATP and rapid cell death. Conversely, either hypoxic adaptation or iron chelation prevents menadione-induced ferroxitosis. Ectopic expression of K213Q HIF-1α mutant blunts the effects of menadione. However, knockdown of HIF-1α or PKM2 restores menadione-induced cytotoxicity in hypoxia. Similarly, exposure of melanoma cells to shikonin, a menadione analog and a potential PKM2 inhibitor, is sufficient to induce ferroxitosis under hypoxic conditions. Collectively, our findings reveal that ferroxitosis curtails metabolic plasticity in melanoma.Item Identification of TMEM230 mutations in familial Parkinson's disease(Nature Research, 2016-07) Deng, Han-Xiang; Shi, Yong; Yang, Yi; Ahmeti, Kreshnik B.; Miller, Nimrod; Huang, Cao; Cheng, Lijun; Zhai, Hong; Deng, Sheng; Nuytemans, Karen; Corbett, Nicola J.; Kim, Myung Jong; Deng, Hao; Tang, Baisha; Yang, Ziquang; Xu, Yanming; Chen, Piao; Huang, Bo; Gao, Xiao-Ping; Song, Zhi; Liu, Zhenhua; Fecto, Faisal; Siddique, Nailah; Foroud, Tatiana; Jankovic, Joseph; Ghetti, Bernardino; Nicholson, Daniel A.; Krainc, Dimitri; Melen, Onur; Vance, Jeffery M.; Pericak-Vance, Margaret A.; Ma, Yong-Chao; Rajput, Ali H.; Siddique, Teepu; Medical and Molecular Genetics, School of MedicineParkinson's disease is the second most common neurodegenerative disorder without effective treatment. It is generally sporadic with unknown etiology. However, genetic studies of rare familial forms have led to the identification of mutations in several genes, which are linked to typical Parkinson's disease or parkinsonian disorders. The pathogenesis of Parkinson's disease remains largely elusive. Here we report a locus for autosomal dominant, clinically typical and Lewy body-confirmed Parkinson's disease on the short arm of chromosome 20 (20pter-p12) and identify TMEM230 as the disease-causing gene. We show that TMEM230 encodes a transmembrane protein of secretory/recycling vesicles, including synaptic vesicles in neurons. Disease-linked TMEM230 mutants impair synaptic vesicle trafficking. Our data provide genetic evidence that a mutant transmembrane protein of synaptic vesicles in neurons is etiologically linked to Parkinson's disease, with implications for understanding the pathogenic mechanism of Parkinson's disease and for developing rational therapies.Item Increasing serum pre-adipocyte factor-1 (Pref-1) correlates with decreased body fat, increased free fatty acids, and level of recent alcohol consumption in excessive alcohol drinkers(Elsevier, 2014-12) Liangpunsakul, Suthat; Bennett, Rachel; Westerhold, Chi; Ross, Ruth A.; Crabb, David W.; Lai, Xianyin; Witzmann, Frank A.; Department of Medicine, IU School of MedicinePatients with alcoholic liver disease have been reported to have a significantly lower percentage of body fat (%BF) than controls. The mechanism for the reduction in %BF in heavy alcohol users has not been elucidated. In adipose tissue, Pref-1 is specifically expressed in pre-adipocytes but not in adipocytes. Pref-1 inhibits adipogenesis and elevated levels are associated with reduced adipose tissue mass. We investigated the association between serum Pref-1 and %BF, alcohol consumption, and serum free fatty acids (FFA) in a well-characterized cohort of heavy alcohol users compared to controls. One hundred forty-eight subjects were prospectively recruited. The Time Line Follow-Back (TLFB) questionnaire was used to quantify the amount of alcohol consumed over the 30-day period before their enrollment. Anthropometric measurements were performed to calculate %BF. Serum Pref-1 and FFA were measured. Fifty-one subjects (mean age 32 ± 9 years, 88% men) were non-excessive drinkers whereas 97 were excessive drinkers (mean age 41 ± 18 years, 69% men). Compared to non-excessive drinkers, individuals with excessive drinking had significantly higher levels of Pref-1 (p<0.01), FFA (p < 0.001), and lower %BF (p = 0.03). Serum levels of Pref-1 were associated with the amount of alcohol consumed during the previous 30 days. Serum Pref-1 was negatively correlated with %BF, but positively associated with serum FFA. Our data suggest that elevated Pref-1 levels in excessive drinkers might inhibit the expansion of adipose tissue, decreasing %BF in alcoholics. Further work is needed to validate these findings and to better understand the role of Pref-1 and its clinical significance in subjects with heavy alcohol use.Item Molecular characterization of outer membrane proteins of Haemophilus ducreyi as immune targets(1997) Hiltke, Thomas JItem Mutations in the CDP-Choline Pathway for Phospholipid Biosynthesis Bypass the Requirement for an Essential Phospholipid Transfer Protein(Cell Press, 1991) Cleves, Ann E.; McGee, Todd P.; Whitters, Eric A.; Champion, Kathleen M.; Aitken, Jacqueline R.; Dowhan, William; Goebl, Mark; Bankaitis, Vytas A.; Biochemistry and Molecular Biology, School of MedicineSEC14p is the yeast phosphatidylinositol (PI)/phosphatidylcholine (PC) transfer protein, and it effects an essential stimulation of yeast Golgi secretory function. We now report that the SEC14p localizes to the yeast Golgi and that the SEC14p requirement can be specifically and efficiently bypassed by mutations in any one of at least six genes. One of these suppressor genes was the structural gene for yeast choline kinase (CKI), disruption of which rendered the cell independent of the normally essential SEC14p requirement. The antagonistic action of the CKI gene product on SEC14p function revealed a previously unsuspected influence of biosynthetic activities of the CDP-choline pathway for PC biosynthesis on yeast Golgi function and indicated that SEC14p controls the phospholipid content of yeast Golgi membranes in vivo.Item Notch ligand Delta-like 1 promotes in vivo vasculogenesis in human cord blood-derived endothelial colony forming cells(Elsevier, 2015-05) Kim, Hyojin; Huang, Lan; Critser, Paul J.; Yang, Zhenyun; Chan, Rebecca J.; Wang, Lin; Carlesso, Nadia; Voytik-Harbin, Sherry L.; Bernstein, Irwin D.; Yoder, Mervin C.; Department of Pediatrics, IU School of MedicineBACKGROUND AIMS: Human cord blood (CB) is enriched in circulating endothelial colony forming cells (ECFCs) that display high proliferative potential and in vivo vessel forming ability. Because Notch signaling is critical for embryonic blood vessel formation in utero, we hypothesized that Notch pathway activation may enhance cultured ECFC vasculogenic properties in vivo. METHODS: In vitro ECFC stimulation with an immobilized chimeric Notch ligand (Delta-like1(ext-IgG)) led to significant increases in the mRNA and protein levels of Notch regulated Hey2 and EphrinB2 that were blocked by treatment with γ-secretase inhibitor addition. However, Notch stimulated preconditioning in vitro failed to enhance ECFC vasculogenesis in vivo. In contrast, in vivo co-implantation of ECFCs with OP9-Delta-like 1 stromal cells that constitutively expressed the Notch ligand delta-like 1 resulted in enhanced Notch activated ECFC-derived increased vessel density and enlarged vessel area in vivo, an effect not induced by OP9 control stromal implantation. RESULTS: This Notch activation was associated with diminished apoptosis in the exposed ECFC. CONCLUSIONS: We conclude that Notch pathway activation in ECFC in vivo via co-implanted stromal cells expressing delta-like 1 promotes vasculogenesis and augments blood vessel formation via diminishing apoptosis of the implanted ECFC.Item Residues involved in phospholemman channel activity(1997) Chen, ZhenhuiItem Structural and Functional Analyses of Liver Cysts from the BALB/c-cpk Mouse Model of Polycystic Kidney Disease(2009) Muchatuta, Monalisa N.; Gattone, Vincent H.; Witzmann, Frank A.; Blazer-Yost, BonnieLiver cysts arising from hepatic bile ducts are a common extra-renal pathology associated with both autosomal dominant and recessive polycystic kidney disease in humans. To elucidate the functional and structural changes inherent in cyst formation and growth, hepatic bile duct epithelia were isolated from the BALB/ c-cpk mouse model of polycystic kidney disease. Light and transmission electron microscopy revealed substantial fibrosis in the basal lamina surrounding hepatic bile duct cysts isolated from heterozygous (BALB/c-cpk/+) and homozygous (BALB/c-cpk/cpk) animals. Scanning electron microscopy and length analysis of normal, precystic and cystic bile ducts provided the unique observation that primary cilia in cholangiocytes isolated from bile ducts and cysts of animals expressing the mutated cpk gene had lengths outside the minimal and maximal ranges of those in cells lining bile ducts of wild-type animals. Based on the hypothesis that PKD is one of several diseases characterized as ciliopathies, this abnormal variability in the length of the primary cilia may have functional implications. Electrophysiological analyses of freshly isolated cysts indicate that the amiloride-sensitive epithelial Na(+) channel (ENaC) is inactive/absent and cAMP-mediated anion secretion is the electrogenic transport process contributing to cyst fluid accumulation. Anion secretion can be stimulated by the luminal stimulation of adenylyl cyclase.Item The TGF-β Signaling Regulator PMEPA1 Suppresses Prostate Cancer Metastases to Bone(Elsevier, 2015-06-08) Fournier, Pierrick GJ; Juárez, Patricia; Jiang, Guanglong; Clines, Gregory A.; Niewolna, Maria; Kim, Hun Soo; Walton, Holly W.; Peng, C. Xiang Hong; Liu, Yunlong; Mohammad, Khalid S.; Wells, Clark D.; Chirgwin, John M.; Guise, Theresa A.; Department of Medicine, IU School of MedicineTransforming growth factor-β (TGF-β) regulates the expression of genes supporting breast cancer cells in bone, but little is known about prostate cancer bone metastases and TGF-β. Our study reveals that the TGFBR1 inhibitor SD208 effectively reduces prostate cancer bone metastases. TGF-β upregulates in prostate cancer cells a set of genes associated with cancer aggressiveness and bone metastases, and the most upregulated gene was PMEPA1. In patients, PMEPA1 expression decreased in metastatic prostate cancer and low Pmepa1 correlated with decreased metastasis-free survival. Only membrane-anchored isoforms of PMEPA1 interacted with R-SMADs and ubiquitin ligases, blocking TGF-β signaling independently of the proteasome. Interrupting this negative feedback loop by PMEPA1 knockdown increased prometastatic gene expression and bone metastases in a mouse prostate cancer model.